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  • 1.
    Inganäs, Olle
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Admassie, Shimelis
    University of Addis Ababa, Ethiopia .
    25th Anniversary Article: Organic Photovoltaic Modules and Biopolymer Supercapacitors for Supply of Renewable Electricity: A Perspective from Africa2014In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 26, no 6, 830-847 p.Article, review/survey (Refereed)
    Abstract [en]

    The role of materials in civilization is well demonstrated over the centuries and millennia, as materials have come to serve as the classifier of stages of civilization. With the advent of materials science, this relation has become even more pronounced. The pivotal role of advanced materials in industrial economies has not yet been matched by the influence of advanced materials during the transition from agricultural to modern societies. The role of advanced materials in poverty eradication can be very large, in particular if new trajectories of social and economic development become possible. This is the topic of this essay, different in format from the traditional scientific review, as we try to encompass not only two infant technologies of solar energy conversion and storage by means of organic materials, but also the social conditions for introduction of the technologies. The development of organic-based photovoltaic energy conversion has been rapid, and promises to deliver new alternatives to well-established silicon photovoltaics. Our recent development of organic biopolymer composite electrodes opens avenues towards the use of renewable materials in the construction of wooden batteries or supercapacitors for charge storage. Combining these new elements may give different conditions for introduction of energy technology in areas now lacking electrical grids, but having sufficient solar energy inputs. These areas are found close to the equator, and include some of the poorest regions on earth.

  • 2.
    Säll, Erik
    et al.
    Linköping University, Department of Electrical Engineering.
    Vesterbacka, Mark
    Linköping University, Department of Electrical Engineering. Linköping University, Department of Electrical Engineering, Electronics System.
    6 bit 1 GHz CMOS silicon-on-insulator flash analog-to-digital converter for read channel applications2005In: Proc. European Conf. on Circuit Theory and Design, ECCTD'05, 2005, I/127-I/130 p.Conference paper (Refereed)
    Abstract [en]

    The purpose of this work is to investigate the possibility to implement analog base band circuitry along with digital circuitry in silicon-on-insulator technology. Hence a 6 bit Nyquist rate flash analog-to-digital converter is designed in a 130 nm CMOS silicon-on-insulator technology. The converter is aimed for read channel or ultra-wideband radio applications. The simulations indicate a 170 mW power consumption at a maximum sampling rate of 1 GHz. The supply voltage is only 1.2 V. The effective number of bit is 5.8 bit and the effective resolution bandwidth is 390 MHz. An energy per conversion step of 3.9 pJ indicate that this converter is as efficient as other state-of-the-art converters, without using interpolation or averaging techniques.

  • 3.
    Harikumar, Prakash
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Wikner, Jacob
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    A 0.4 V, sub-nW, 8-bit 1 kS/s SAR ADC in 65 nm CMOS for Wireless Sensor Applications2016In: IEEE Transactions on Circuits and Systems - II - Express Briefs, ISSN 1549-7747, E-ISSN 1558-3791, Vol. 63, no 8, 743-747 p.Article in journal (Refereed)
    Abstract [en]

    This brief presents an 8-bit 1-kS/s successive approximation register (SAR) analog-to-digital converter (ADC), which is targeted at distributed wireless sensor networks powered by energy harvesting. For such energy-constrained applications, it is imperative that the ADC employs ultralow supply voltages and minimizes power consumption. The 8-bit 1-kS/s ADC was designed and fabricated in 65-nm CMOS and uses a supply voltage of 0.4 V. In order to achieve sufficient linearity, a two-stage charge pump was implemented to boost the gate voltage of the sampling switches. A custom-designed unit capacitor of 1.9 fF was used to realize the capacitive digital-to-analog converters. The ADC achieves an effective number of bits of 7.81 bits while consuming 717 pW and attains a figure of merit of 3.19 fJ/conversion-step. The differential nonlinearity and the integral nonlinearity are 0.35 and 0.36 LSB, respectively. The core area occupied by the ADC is only 0.0126 mm2.

  • 4.
    Fazli Yeknami, Ali
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 0.5-V 250-nW 65-dB SNDR Passive ΔΣ Modulator for Medical Implant Devices2013In: Proceedings of the IEEE International Symposium on Circuits and Systems (ISCAS), Beijing, China, 19-23 May, 2013, 2013, 2010-2013 p.Conference paper (Refereed)
    Abstract [en]

    A  0.5-V  ultra-low-power  second-order  DT  DS  modulator  is  presented  in  this  paper  for  medical  implant  devices.  The  modulator  employs  2nd-order  passive  low-pass filter  and  ultra-low-voltage  building  blocks,  including preamplifier, regenerative comparator, and clock controller, in order  to enable operation near 0.5 V supply. A  low-noise and gain-enhanced  single-stage  preamplifier  is  developed  using  a body-driven technique. Passive filter is gain boosted by power-efficient charge-redistribution amplification  scheme. Designed in  a  65nm CMOS  technology,  the modulator  achieves  65  dB peak SNDR over a 500 Hz signal bandwidth, while it consumes 250 nW  from  a  0.5 V  supply. The modulator  is  functional  at 0.45V and obtains 52 dB SNR, while consuming 200 nW.

  • 5.
    Fazli Yeknami, Ali
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 0.7-V 600-nW 87-dB SNDR DT-Delta Sigma Modulator with Partly Body-Driven and Switched Op-amps for Biopotential Signal Acquisition2012In: 2012 IEEE BIOMEDICAL CIRCUITS AND SYSTEMS CONFERENCE (BIOCAS): INTELLIGENT BIOMEDICAL ELECTRONICS AND SYSTEM FOR BETTER LIFE AND BETTER ENVIRONMENT, IEEE , 2012, 336-339 p.Conference paper (Refereed)
    Abstract [en]

    A 0.7 V third-order DT Delta Sigma modulator is presented in this paper for measurement of biopotential signals in portable medical applications. Switched-opamp technique has been adopted in this design to eliminate the critical switches, which leads to low-voltage and low-power consumption. The modulator employs new partially body-driven gain-enhanced amplifiers for low-voltage operation in order to compensate the dc gain degradation. Switched-opamp approach is embedded in amplifiers and CMFB circuits to reduce the power consumption. The major building blocks, such as the proposed Class AB gain-enhanced amplifiers and the low-voltage comparator, use body-biased p-MOS to reduce the threshold voltage, thus providing more voltage headroom in the low voltage environment. Noise analysis, as a critical step in the design of a high resolution ADC, is also provided. Designed in a 65nm CMOS technology, the modulator achieves 87 dB peak SNDR over a 500 Hz signal bandwidth, while it consumes 600-nW from a 0.7 V supply.

  • 6.
    Harikumar, Prakash
    et al.
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Wikner, Jacob
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A 10-bit 50 MS/s SAR ADC in 65 nm CMOS with On-Chip Reference Voltage Buffer2015In: Integration, ISSN 0167-9260, E-ISSN 1872-7522, Vol. 50, 28-38 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents the design of a 10-bit, 50 MS/s successive approximation register (SAR) analog-to-digital converter (ADC) with an onchip reference voltage buffer implemented in 65 nm CMOS process. The speed limitation on SAR ADCs with off-chip reference voltage and the necessity of a fast-settling reference voltage buffer are elaborated. Design details of a high-speed reference voltage buffer which ensures precise settling of the DAC output voltage in the presence of bondwire inductances are provided. The ADC uses bootstrapped switches for input sampling, a double-tail high-speed dynamic comparator and split binary-weighted capacitive array charge redistribution DACs. The split binary-weighted array DAC topology helps to achieve low area and less capacitive load and thus enhances power efficiency. Top-plate sampling is utilized in the DAC to reduce the number of switches. In post-layout simulation which includes the entire pad frame and associated parasitics, the ADC achieves an ENOB of 9.25 bits at a supply voltage of 1.2 V, typical process corner and sampling frequency of 50 MS/s for near-Nyquist input. Excluding the reference voltage buffer, the ADC consumes 697 μW and achieves an energy efficiency of 25 fJ/conversionstep while occupying a core area of 0.055 mm2.

  • 7.
    Ahsan, Naveed
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Svensson, Christer
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Ramzan, Rashad
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Dąbrowski, Jerzy
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Ouacha, Aziz
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Samuelsson, Carl
    Swedish Defence Research Agency (FOI), P.O. Box 1165, SE-581 11 Linköping, Sweden.
    A 1.1V 6.2mW, Highly Linear Wideband RF Front-end for Multi-Standard Receivers in 90nm CMOS2012In: Analog Integrated Circuits and Signal Processing, ISSN 0925-1030, E-ISSN 1573-1979, Vol. 70, no 1, 79-90 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents the design and implementation of a low power, highly linear, wideband RF front-end in 90nm CMOS. The architecture consists of an inverter-like common gate low noise amplifier followed by a passive ring mixer. The proposed architecture achieves high linearity in a wide band (0.5-6GHz) at very low power. Therefore, it is a suitable choice for software defined radio (SDR) receivers. The chip measurement results indicate that the inverter-like common gate input stage has a broadband input match achieving S11 below -8.8dB up to 6GHz. The measured single sideband noise figure at an LO frequency of 2GHz and an IF of 10MHz is 6.25dB. The front-end achieves a voltage conversion gain of 4.5dB at 1GHz with 3dB bandwidth of more than 6GHz. The measured input referred 1dB compression point is +1.5dBm while the IIP3 is +11.73dBm and the IIP2 is +26.23dBm respectively at an LO frequency of 2GHz. The RF front-end consumes 6.2mW from a 1.1V supply with an active chip area of 0.0856mm2.

  • 8.
    Krishnamurthy, R.K.
    et al.
    Microprocessor Res. Labs., Intel Corp., Hillsboro, OR .
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Balamurugan, G.
    Microprocessor Res. Labs., Intel Corp., Hillsboro, OR .
    Shanbhag, R.
    Microprocessor Res. Labs., Intel Corp., Hillsboro, OR .
    Soumyanath, K.
    Microprocessor Res. Labs., Intel Corp., Hillsboro, OR .
    Borkar, S.Y.
    Microprocessor Res. Labs., Intel Corp., Hillsboro, OR .
    A 130-nm 6-GHz 256x32 bit leakage-tolerant register file2002In: IEEE Journal of Solid-State Circuits, ISSN 0018-9200, Vol. 37, no 5, 624-632 p.Article in journal (Refereed)
    Abstract [en]

    Describes a 256-word × 32-bit 4-read, 4-write ported register file for 6-GHz operation in 1.2-V 130-nm technology. The local bitline uses a pseudostatic technique for aggressive bitline active leakage reduction/tolerance to enable 16 bitcells/bitline, low-Vt usage, and 50% keeper downsizing. Gate-source underdrive of -V cc on read-select transistors is established without additional supply/bias voltages or gate-oxide overstress. 8% faster read performance and 36% higher dc noise robustness is achieved compared to dual-Vt bitline scheme optimized for high performance. Device-level measurements in the 130-nm technology show 703× bitline active leakage reduction, enabling continued Vt scaling and robust bitline scalability beyond 130-nm generation. Sustained performance and robustness benefit of the pseudostatic technique against conventional dynamic bitline with keeper-upsizing is also presented

  • 9.
    Säll, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Electronics System.
    A 1.8V 10-bit 80MS/s Low Power Track-and-Hold Circuit in a 0.18µm CMOS Process2003In: IEEE International Symposium on Circuits and Systems, ISCAS,2003, 2003Conference paper (Other academic)
    Abstract [en]

    A 10-bit low power track-and-hold (T&H) circuit aimed for the front-end of a pipelined analog-to-digital (A/D) converter has been designed. The T&H is sampling at 80MS/s, has a 30MHz analog bandwidth and was designed in a 0.18um CMOS process with a supply voltage of 1.8 Volt. A switched capacitor topology applying correlated double sampling is used for the T&H circuit and the amplifier is a folded cascode OTA with gain boosting. This paper describes the design of the complete T&H, including the derivation of the specifications as well as a straightforward approach for designing the transmission gate switches.

  • 10.
    Fazli Yeknami, Ali
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 2.1 mu W 80 dB SNR DT Delta I pound modulator for medical implant devices in 65 nm CMOS2013In: Analog Integrated Circuits and Signal Processing, ISSN 0925-1030, E-ISSN 1573-1979, Vol. 77, no 1, 69-78 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents a simple and robust low-power Delta I pound modulator for accurate ADCs in implantable cardiac rhythm management devices such as pacemakers. Taking advantage of the very low signal bandwidth of 500 Hz which enables high oversampling ratio, the objective is to obtain high SNDR and low power consumption, while limiting the complexity of the modulator to a second-order architecture. Significant power reduction is achieved by utilizing a two-stage load-compensated OTA as well as the low-V-T devices in analog circuits and switches, allowing the modulator to operate at 0.9 V supply. Fabricated in a 65 nm CMOS technology, the modulator achieves 80 dB peak SNR and 76 dB peak SNDR over a 500 Hz signal bandwidth. With a power consumption of 2.1 mu W, the modulator obtains 0.4 pJ/step FOM. To the authors knowledge, this is the lowest reported FOM, compared to the previously reported second-order modulators for such low-speed applications. The achieved FOM is also comparable to the best reported results from the higher-order Delta I pound modulators.

  • 11.
    Yeknami, Ali Fazli
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 2.1 uW 76 dB SNDR DT-ΔΣ Modulator for Medical Implant Devices2012In: NORCHIP 2012, IEEE , 2012, 1-4 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a low-power 2nd-order discrete-time (DT) ΔΣ analog-to-digital converter (ADC) aimed for medical implant devices. The designed ΔΣ modulator with two active integrators (filters) employs power-efficient two-stage load-compensated OTAs with minimal load and rail-to-rail output swing, which provides higher power-efficiency than the two-stage Miller OTA. The modulator, implemented in a 65nm CMOS technology with a core area of 0.033 mm2, achieves 76-dB peak SNDR over a 500 Hz signal bandwidth, while consuming 2.1 µW from a 0.9 V supply voltage. Compared to previously reported modulators for such signal bandwidths, the achieved performance (FOM of 0.4 pJ/step) make the presented modulator one of the best among sub-1-V modulators in term of most commonly used figure of merit.

  • 12.
    Mesgarzadeh, Behzad
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 24-mW, 0.02-mm2, 1.5-GHz DLL-Based Frequency Multiplier in 130-nm CMOS2006In: Proceedings of the IEEE International System-on-Chip Conference (SoCC), 2006, 257-260 p.Conference paper (Other academic)
    Abstract [en]

    This paper presents a low-power small-area DLL-based frequency multiplier. Instead of using edge combiner-based clock synthesis scheme, the proposed frequency multiplier utilizes a ring oscillator, which is controlled by a DLL. An injection-locked slave ring oscillator is used for jitter suppression. The implementation of the proposed structure in 130-nm CMOS occupies an area of 0.02 mm2. It operates in the frequency range of 100 MHz to 1.5 GHz while consuming 24-mW power from a 1.2-V supply at 1.5 GHz. The measured output phase noise at 1.5 GHz is ¿100.1 dBc/Hz at a 4-MHz frequency offset.

  • 13.
    Fazli Yeknami, Ali
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 270-mV  ΔΣ Modulator Using Gain-Enhanced, Inverter-Based Amplifier2013Manuscript (preprint) (Other academic)
    Abstract [en]

    An ultra-low-voltage low-power switched-capacitor ΔΣ modulator running at a supply voltage as low as 270 mV is presented for medical implant devices. To reduce the supply voltage and power consumption, an inverter-based amplifier is used in the integrator, whose DC-gain and gain-bandwidth (GBW) are boosted by a simple current-mirror output stage. The full feedforward loop topology offers low integrators internal swing, supporting ultra-low-voltage operation. The entire modulator operates at 270 mV supply only, while the switches are driven by charge pump clock doubler. Designed in 65 nm CMOS and clocked at 256 kHz, the simulation results show that the converter achieves 64.4 dB signal-to-noise-ratio (SNR) and 61 dB signal-to-noise-and-distortionratio (SNDR) in 1 kHz bandwidth while consuming 0.85 "W power.

  • 14.
    Mesgarzadeh, Behzad
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 2-GHz 7-mW Digital DLL-Based Frequency Multiplier in 90-nm CMOS2008In: ESSCIRC 2008 - Proceedings of the 34th European Solid-State Circuits Conference, Bristol, UK: IOP Institute of Physics , 2008, 86-89 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a low-power low-jitter digital DLL-based frequency multiplier in 90-nm CMOS. In order to reduce the jitter and power consumption due to dithering in the lock condition, digital DLL operates in the open-loop mode after locking. To keep track of any potential phase error introduced by the environmental variations, a compensation mechanism is employed. The proposed frequency multiplier operates at 2-GHz utilizing a 1-V supply. It occupies 0.037 mm2 of active area and dissipates 7-mW power at 2-GHz. The measured peak-to-peak and rms clock jitter at the output of the frequency multiplier are 9.5 ps and 1.6 ps, respectively.   

  • 15.
    Fritzin, Jonas
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Svensson, Christer
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A +32dBm 1.85GHz Class-D Outphasing RF PA in 130nm CMOS for WCDMA/LTE2011In: Proceedings of the IEEE European Solid-State Circuits Conference (ESSCIRC), IEEE , 2011, 127-130 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a Class-D outphasing RF Power Amplifier (PA) which can operate at a 5.5V supply and deliver +32dBm at 1.85 GHz in a standard 130nm CMOS technology. The PA utilizes four on-chip transformers to combine the outputs of eight Class-D stages. The Class-D stages utilize a cascode configuration, driven by an AC-coupled low-voltage driver, to allow a 5.5 V supply in the 1.2/2.5 V 130nm process without excessive device voltage stress. Spectral and modulation requirements were met when a WCDMA and an LTE signal (20 MHz, 16-QAM) were applied to the outphasing PA. At +28.0 dBm channel power for the WCDMA signal, the measured ACLR at 5 MHz and 10 MHz offset were −38.7 dBc and −47.0 dBc, respectively. At +24.9 dBm channel power for the LTE signal, the measured ACLR at 20MHz offset was −34.9 dBc. To the authors' best knowledge, the PA presented in this work has a 3.9 dB higher output power compared to published CMOS Class-D RF PAs.

  • 16.
    Zhang, Dai
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 3-nW 9.1-ENOB SAR ADC at 0.7 V and 1 kS/s2012In: ESSCIRC, 2012, Institute of Electrical and Electronics Engineers , 2012, 369-372 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a 10-bit SAR ADC in 65 nm CMOS for medical implant applications. The ADC consumes 3-nW power and achieves 9.1 ENOB at 1 kS/s. The ultra-low-power consumption is achieved by using an ADC architecture with maximal simplicity, a small split-array capacitive DAC, a bottom-plate sampling approach reducing charge injection error and allowing full-range input sampling without extra voltage sources, and a latch-based SAR control logic resulting in reduced power and low transistor count. Furthermore, a multi-Vt circuit design approach allows the ADC to meet the target performance with a single supply voltage of 0.7 V. The ADC achieves a FOM of 5.5 fJ/conversion-step. The INL and DNL errors are 0.61 LSB and 0.55 LSB, respectively.

  • 17.
    Zhang, Dai
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices.
    A 3-nW 9.1-ENOB SAR ADC at 0.7 V and 1 kS/s2013Conference paper (Other academic)
    Abstract [en]

    This paper presents a 10-bit SAR ADC in 65 nm CMOS for medical implant applications. The ADC consumes 3-nW power and achieves 9.1 ENOB at 1 kS/s. The ultra-low-power consumption is achieved by using an ADC architecture with maximal simplicity, a small split-array capacitive DAC, a bottom-plate sampling approach reducing charge injection error and allowing full-range input sampling without extra voltage sources, and a latch-based SAR control logic resulting in reduced power and low transistor count. Furthermore, a multi-Vt circuit design approach allows the ADC to meet the target performance with a single supply voltage of 0.7 V. The ADC achieves a FOM of 5.5 fJ/conversion-step. The INL and DNL errors are 0.61 LSB and 0.55 LSB, respectively.

  • 18.
    Zhang, Dai
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Bhide, Ameya
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 53-nW 9.12-ENOB 1-kS/s SAR ADC in 0.13-um CMOS for medical implant devices2011In: Proceedings of the IEEE European Solid-State Circuits Conference (ESSCIRC), Helsinki, Finland: IEEE Solid-State Circuits Society, 2011, 467-470 p.Conference paper (Refereed)
    Abstract [en]

    This paper describes an ultra-low-power SAR ADC in 0.13-um CMOS technology for medical implant devices. It utilizes an ultra-low-power design strategy, imposing maximum simplicity in ADC architecture, low transistor count, low-voltage low-leakage circuit techniques, and matched capacitive DAC with a switching scheme which results in full-range sampling without switch bootstrapping and extra reset voltage. Furthermore, a dual-supply scheme allows the SAR logic to operate at 400mV. The ADC has been fabricated in 0.13-um CMOS. In 1.0-V single-supply mode, the ADC consumes 65nW at a sampling rate of 1kS/s, while in dual-supply mode (1.0V for analog and 0.4V for digital) it consumes 53nW (18% reduction) and achieves the same ENOB of 9.12. 24% of the 53-nW total power is due to leakage. To the authors' best knowledge, this is the lowest reported power consumption of a 10-bit ADC for such sampling rates.

  • 19.
    Zhang, Dai
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Bhide, Ameya
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 53-nW 9.1-ENOB 1-kS/s SAR ADC in 0.13-μm CMOS for Medical Implant Devices2012In: IEEE Journal of Solid-State Circuits, ISSN 0018-9200, Vol. 47, no 7, 1585-1593 p.Article in journal (Refereed)
    Abstract [en]

    This paper describes an ultra-low power SAR ADC for medical implant devices. To achieve the nano-watt range power consumption, an ultra-low power design strategy has been utilized, imposing maximum simplicity on the ADC architecture, low transistor count and matched capacitive DAC with a switching scheme which results in full-range sampling without switch boot-strapping and extra reset voltage. Furthermore, a dual-supply voltage scheme allows the SAR logic to operate at 0.4 V, reducing the overall power consumption of the ADC by 15% without any loss in performance. The ADC was fabricated in 0.13-mu m CMOS. In dual-supply mode (1.0 V for analog and 0.4 V for digital), the ADC consumes 53 nW at a sampling rate of 1 kS/s and achieves the ENOB of 9.1 bits. The leakage power constitutes 25% of the 53-nW total power.

  • 20.
    Vangal, Sriram R.
    et al.
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    Hoskote, Yatin V.
    Intel Microprocessor Technology Labs.
    Borkar, Nitin Y.
    Intel Microprocessor Technology Labs.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 6.2 GFLOPS Floating Point Multiply-Accumulator with Conditional Normalization2006In: IEEE Journal of Solid-State Circuits, ISSN 0018-9200, Vol. 41, no 10, 2314-2323 p.Article in journal (Refereed)
    Abstract [en]

    A pipelined single-precision floating-point multiply-accumulator (FPMAC) featuring a single-cycle accumulate loop using base 32 and internal carry-save arithmetic with delayed addition is described. A combination of algorithmic, logic, and circuit techniques enables multiply-accumulate operations at speeds exceeding 3 GHz with single-cycle throughput. The optimizations allow removal of the costly normalization step from the critical accumulate loop. This logic is conditionally powered down using dynamic sleep transistors on long accumulate operations, saving active and leakage power. In addition, an improved leading-zero anticipator (LZA) and overflow prediction logic applicable to carry-save format is presented. In a 90-nm seven-metal dual-VT CMOS process, the 2 mm2 custom design contains 230K transistors. The fully functional first silicon achieves 6.2 GFlops of performance while dissipating 1.2 W at 3.1 GHz, 1.3-V supply

  • 21.
    Aamir, Syed Ahmed
    Linköping University. Linköping University, Department of Electrical Engineering.
    A 65nm, Low Voltage, Fully Differential, SC Programmable Gain Amplifier for Video AFE2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to rapid growth of home entertainment consumer market, video technology has been continuously pushed to deliver sharper pictures with higher resolution. This has brought about stringent requirements on the video analog front end, which often coupled with the low power and low voltage regulations had to deal with short channel effects of the deep submicron CMOS processes.

    This thesis presents the design of a fully differential programmable gain amplifier, as a subcircuit of a larger video digitizing IC designed at division of Electronic Systems. The switched capacitor architecture of the PGA does not only buffer the signal, but performs compensation for the sync-tip of analog video signal.

    The pseudo differential OTA eliminates tail current source and maintains high signal swing and has efficient common mode feedforward mechanism. When coupled with a similar stage provides inherent common moode feedback without using an additional SC-CMFB block.

    The PGA has been implemented using a 65 nm digital CMOS process. Expected difficulties in a 1.2 V OTA design make themselves evident in 65 nm, which is why cascaded OTA structures were inevitable for attaining gain specification of 60 dB. Nested Miller compensation with a pole shifting source follower, stabilizes the multipole system. The final circuit attains up to 200 MHz bandwidth and maintains high output swing of 0.85 V. High slew rate and good common mode and power supply rejection are observed. Noise requirements require careful design of input differential stage. Although output source follower stabilized the system, it reduces significant bandwidth and adds to second order non-linearity.

  • 22.
    Khan, H.R.
    et al.
    Electronic Engineering Department, NED University of Engineering and Technology, Karachi, Pakistan.
    Wahab, Q.
    Electronic Engineering Department, NED University of Engineering and Technology, Karachi, Pakistan.
    Fritzin, Jonas
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Wahab, Qamar
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    A 900 MHz 26.8 dBm differential Class-E CMOS power amplifier in German Microwave Conference Digest of Papers, GeMIC 2010, vol , issue , pp 276-2792010In: German Microwave Conference Digest of Papers, GeMIC 2010, 2010, 276-279 p.Conference paper (Refereed)
    Abstract [en]

    A 900 MHz differential Class-E amplifier with finite dc inductance has been designed in CMOS. The large inductance of RF choke has been replaced with a finite inductance that provides the required inductive reactance of the class E amplifier. Resonance circuit is realized without series inductor by novel use of lattice LC balun. The amplifier delivers 26.8 dBm power to a 50 O load from a 2.2 V supply. A maximum Power Added Efficiency (PAE) of 43% is achieved.

  • 23.
    Hsu, Steven
    et al.
    Intel Corp., Hillsboro, USA.
    Chatterjee, Bhaskar
    Dpt El.and Computer Engineering University of Waterloo, Ontario, Canada.
    Sachdev, Manjo
    Dpt El. and Comupter Engineering University of Waterloo, Ontario, Canada.
    Alvandpour, Atila
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Electronic Devices.
    Krishnamurthy, Ram
    Intel Corp., Hillsboro, USA.
    Borkar, Shekhar
    Intel Corp., Hillsboro, USA.
    A 90nm 6.5GHz 256x64b dual supply register file with split decoder scheme.2003In: Symposium on VLSI circuits,2003, Tokyo: Business Center fo Academic Societies Japan , 2003, 237- p.Conference paper (Refereed)
  • 24.
    Vesterbacka, Mark
    et al.
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Palmkvist, Kent
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Wanhammar, Lars
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A CAD tool for synthesis of maximally fast lattice wave digital filters1999In: Proc. National Conf. on Radio Science and Communication, RVK'99, 1999, 456-460 p.Conference paper (Other academic)
    Abstract [en]

    A synthesis tool has been developed that implements the scheduling and the hardware mapping of maximally fast, bit-serial lattice wave digital filters. Such implementa­tions are of interest for use in high-speed applications or in low-power applications after supply voltage scaling. The tool generates a synthesizable VHDL hardware netlist from a set of coefficients describing the filter. The VHDL netlist is further mapped to an ASIC using tools from Mentor Graphics. Currently the tool is capable of synthesizing two lattice wave digital filter structures as well as optimizing the structure for cases like the birecip­rocal form of the filter.

  • 25.
    Evangelista, Pietro
    et al.
    IRAT-CNR and Department of Management and Engineering, University of Naples Federico II, Italy.
    Huge-Brodin, Maria
    Linköping University, Department of Management and Engineering, Logistics Management. Linköping University, The Institute of Technology.
    Isaksson, Karin
    Linköping University, Department of Management and Engineering, Logistics Management. Linköping University, The Institute of Technology.
    Sweeney, Edward
    National Institute for Transport and Logistics, Dublin Institute of Technology, Ireland.
    A case study investigation on purchasing green transport and logistics services2012In: Purchasing & Supply Management in a Changing World: IPSERA 2012 Conference Proceedings / [ed] Esposito, E., Evangelista, P., Pastore, G., Raffa, M., Napoli, Italia: Edizioni Scientifiche Italiane , 2012, WP17-1-WP17-13 p.Conference paper (Refereed)
    Abstract [en]

    n the context of green supply chain management, green purchasing has received increased attention over the past decade and the strategic importance of introducing green aspects into purchasing practices has been recognised. Despite this growing importance, little has been written in relation to purchasing green transport and logistics services. Considering the strong environmental impact associated with transport and logistics activities, much remains to be learned concerning buyer’s practices when sourcing more sustainable services from third party logistics companies (3PLs). The aim of this paper is to explore practices of buying green transport and logistics services in three different European countries (Italy, Ireland and Sweden) using a multiple case study research approach. The paper analyses how general environmental company ambitions and environmental purchasing practices are reflected when green transport and logistics services are purchased. The results of the paper indicate that while the case companies show a relatively high concern of green issues at company level, a lower importance is attributed to green issues at the purchasing function level. When green concerns in purchasing transport and logistics services are analysed the level of importance decrease dramatically. It emerges a conflicting attitude among the overall company level and the purchasing of transport and logistics services. This suggests that there is the potential for improvements especially in the area of green collaboration in buyer and supplier relationships. 

  • 26.
    Strand, Joel
    et al.
    Linköping University, Department of Management and Engineering, Production Economics.
    Strandänger, Louise
    Linköping University, Department of Management and Engineering, Production Economics.
    A case study on how an e-tailer can use a multiple criteria ABC analysis to identify risk in the selection of suppliers2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Purpose – The purpose of this master thesis is to explore how an e-tailer selling bulky items can use a multiple criteria ABC analysis to make its purchasing process more effective, while balancing richness and reach, with the performance measurements of profitability, total asset turnover and inventory turnover. The purpose will be accomplished through a single case study on an e-tailer active on the Swedish furniture and home furnishing market.

    Methodology – This thesis applies a multiple criteria ABC-analysis to a single case study. The approach is semi-deductive as theory is combined with interviews on how to match and adapt theory about inventory control and purchasing with the specific requirements of an e-tailer selling bulky items.

    Findings – This thesis has resulted in a set of recommendations that aim to make the purchasing process of an e-tailer more effective. That is, capital and inventory space will be better allocated to the e-tailer’s more profitable items. Among other things, this thesis shows how dead articles can be identified and how a purchaser can prioritize more profitable articles over less profitable ones when making procurement decisions. The other recommendations are for the e-tailer to investigate the possibilities of decoupling the supply chain by keeping stock at the suppliers’ premises, to match the supplier reliability with their importance in the supply chain, and lastly to explore possibilities of drop shipment. Further, the main finding is that a comparison between the A-, B-, and C-classes and the reliability of the suppliers, highlights a gap and a possible risk. Put differently, the importance of a specific item for the business should be reflected in the choice of supplier and the multiple criteria ABC analysis is the tool to illustrate the importance.

    Keywords – E-commerce, E-tailer, richness, reach, transaction cost, ABC analysis, multiple criteria ABC, MCABC, inventory turnover ratio, supplier selection, purchasing

    Paper type – Masters thesis

  • 27.
    Wetterö, Jonas
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology . Linköping University, Faculty of Health Sciences.
    Pettersson, Sofia
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Surgery .
    Holmgren Peterson, Kajsa
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    A cellular imaging CDIO project for 2nd semester students in engineering biology2006In: World Transactions on Engineering and Technology Education, ISSN 1446-2257, Vol. 5, no 2, 279-282 p.Article in journal (Refereed)
    Abstract [en]

    The demand for exact engineering within the life sciences is growing and the Engineering Biology programme at Linköping University, Linköping, Sweden, prepares students for a career at this interface. Conceive – Design – Implement – Operate (CDIO) was recently pioneered in an introductory project course. Groups of six to seven students apply a LIPS scalable project model from traditional engineering educational environments on, for example, a cellular imaging task in a hospital setting, prior to taking courses in cell biology/optics. Besides facilitating the implementation of CDIO in higher courses, students gain early career insight and enhance their communication skills. A customer (senior teacher) needs to visualise structures in cells, and the student group is contracted to deliver an applied and optimised method to meet specified requirements. The customer reviews deliverables before the tollgates and communicates with the student project leader. Other students are responsible for documentation and subsystems. The project is allocated laboratory facilities and hardware, and two fictitious subcontractors supply samples and consumables. Extra teachers perform supervision and methodological consultation. In summary, CDIO is indeed applicable and rewarding in cellular imaging, yet is also challenging.

  • 28.
    Fritzin, Jonas
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Svensson, Christer
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A Class-D outphasing RF amplifier with harmonic suppression in 90nm CMOS2010In: Proceedings of the ESSCIRC, 2010, Seville: IEEE , 2010, 310-313 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a low-power Class-D stage featuring a new harmonic reduction technique, which cancels the 3rd harmonic and reduces the 5th harmonic. The technique creates a voltage level of VDD/2 from a single supply voltage to shape the drain voltage, uses only digital circuits and eliminates the short-circuit current present in inverter-based Class-D stages. From a single Class-D stage operating at 900MHz, the measured output power is +5.1dBm with Drain Efficiency (DE) and Power-Added Efficiency (PAE) of 73% and 59% for a 1.2V supply, while 2nd to 4th harmonics are measured to be -37dBc without any filtering. Connecting two Class-D stages to a PCB-mounted transformer in an outphasing configuration, the overall amplifier is linear enough to amplify EDGE 8-PSK and WCDMA modulated signals at 900MHz without pre-distortion of the input signals or any other linearization technique.

  • 29.
    Fritzin, Jonas
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Mesgarzadeh, Behzad
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A Class-D Stage with Harmonic Suppression and DLL-Based Phase Generation2012In: 2012 IEEE 55TH INTERNATIONAL MIDWEST SYMPOSIUM ON CIRCUITS AND SYSTEMS (MWSCAS), Lida Ray Technologies Inc., , 2012, 45-48 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a Class-D stage with 3rd harmonic suppression operating at 2V(DD) (i.e., twice the nominal supply voltage). A DLL-based phase generator is used to generate the phases of the driving signals and by modifying the driver stage 5th harmonic suppression is also possible. The output stage and drivers are based on inverters only, where the short-circuit current is eliminated in the output stage. Operating at 1 GHz, the simulated output power is +19.4 dBm utilizing a 1-V supply and a 5-Omega load, with Drain Efficiency (DE) and Power-Added Efficiency (PAE) of 72% and 52%, respectively, including power dissipation in the DLL-based phase generator and drivers. The 3rd harmonic is suppressed 23 dB (-33 dBc) compared to a conventional Class-D stage.

  • 30.
    Bengtsson, Mikael
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A clock driver with reduced EMI2014Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A clock driver that works on the principle of charging and discharging the clock network in a VLSI circuit in two steps is investigated in a few different configurations. The aim of the design is twofold:

    • to reduce the power consumption
    • to reduce the third harmonic of the clock signal, and thereby the EMI (electromagnetic interference) emitted by the clock network.

    The first should be possible to accomplish as the clock interconnect network gets charged by half the voltage during each rising transition, and the second should be possible to accomplish by carefully time the rising and falling transitions, so that the third Fourier coefficient of the resulting wave form cancels.

    The drivers are loaded by eight 16-bit adders. The drivers’ power consumption, and the spectrum of the output signal, are investigated under varying clock frequencies, power supply voltage, and driver architecture. The results are compared to a conventional square wave clock.

    The results are that while the third harmonics of the resulting output sees an improvement in all the investigated cases over the square wave clock, the power savings are, for higher clock frequencies, more than completely canceled by the extra power needed in the logic stage which controls these drivers. On the other hand, the power consumption of the new driver appears to drop below that of the conventional driver when the clock frequency drops below approximately 100MHz.

    A few suggestions for further investigations of new designs and clock wave forms are given.

  • 31.
    Shutova, T
    et al.
    Umeå University.
    Klimov, VV
    Russian Academy of Sciences.
    Andersson, Bertil
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Samuelsson, G
    Umeå University.
    A cluster of carboxylic groups in PsbO protein is involved in proton transfer from the water oxidizing complex of Photosystem II2007In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1767, no 6, 434-440 p.Article in journal (Refereed)
    Abstract [en]

    The hypothesis presented here for proton transfer away from the water oxidation complex of Photosystem II (PSII) is supported by biochemical experiments on the isolated PsbO protein in solution, theoretical analyses of better understood proton transfer systems like bacteriorhodopsin and cytochrome oxidase, and the recently published 3D structure of PS II (Pdb entry IS5L). We propose that a cluster of conserved glutamic and aspartic acid residues in the PsbO protein acts as a buffering network providing efficient acceptors of protons derived from substrate water molecules. The charge delocalization of the cluster ensures readiness to promptly accept the protons liberated from substrate water. Therefore protons generated at the catalytic centre of PSII need not be released into the thylakoid lumen as generally thought. The cluster is the beginning of a localized, fast proton transfer conduit on the lumenal side of the thylakoid membrane Proton-dependent conformational changes of PsbO may play a role in the regulation of both supply of substrate water to the water oxidizing complex and the resultant proton transfer.

  • 32.
    Tan, Nianxiong
    et al.
    Micro Electron. Res. Center, Ericsson Components AB, Stockholm .
    Wikner, Jacob
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A CMOS digital-to-analog converter chipset for telecommunication1997In: IEEE Circuits & Devices, ISSN 8755-3996, E-ISSN 1558-1888, Vol. 13, no 2, 11-16 p.Article in journal (Refereed)
    Abstract [en]

    Describes a DAC chipset developed specifically for telecommunication applications. The DAC chipset is implemented in Ericsson's in-house 0.6-micron CMOS process and operates on a supply voltage ranging from 1.5 V to 5 V with the number of bits ranging from 10 to 14 bits, and data rate from 50 Msamples/s@1.5 V to over 100 Msamples/s@5 V

  • 33.
    Gunnarsson (Lidestam), Helene
    et al.
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Rönnqvist, Mikael
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Carlsson, Dick
    Södra Cell AB, Växjö, Sweden.
    A combined terminal location and ship routing problem2006In: Journal of the Operational Research Society, ISSN 0160-5682, Vol. 57, no 8, 928-938 p.Article in journal (Refereed)
    Abstract [en]

    In this paper, we consider a combined terminal location and ship routing problem at Södra Cell AB. The purpose is to supply the customers' annual demand for pulp products while minimizing the distribution costs. Customers are supplied with various pulp products from pulp mills in Scandinavia by ships, trains, or lorries. The ship routes go from the pulp mills to terminals in Europe. From each terminal, the products are transported to customers by lorry, train, or barge. Some customers can be supplied directly from the pulp mills by trains or lorries. We have developed a mathematical model to select which terminals to use and, at the same time, determine the shipping routes. The mixed integer programming model was solved directly using a commercial solver. When the number of routes generated is large, the time required to obtain an optimal solution is too long. Hence, we have developed heuristics in order to obtain an acceptable solution in reasonable time. In addition to the basic case, five different scenarios were tested. Our heuristics provide solutions that are within 0.12% of the optimal ones.

  • 34.
    Hassanli, Kourosh
    et al.
    Isfahan University of Technology, Iran.
    Masoud Sayedi, Sayed
    Isfahan University of Technology, Iran.
    Wikner, Jacob
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    A compact, low-power, and fast pulse-width modulation based digital pixel sensor with no bias circuit2016In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 244, 243-251 p.Article in journal (Refereed)
    Abstract [en]

    A high-speed and compact in-pixel light-to-time converter (LTC), with low power consumption and wide dynamic range is presented. By using the proposed LTC, a digital pixel sensor (DPS) based on a pulse width modulation (PWM) scheme has been designed and fabricated in a standard 180-nm, single-poly, six-metal complementary metal oxide semiconductor (CMOS) technology. The prototype chip consists of a 16 x 16 pixel array with an individual pixel size of 21 x 21 mu m(2) and a fill factor of 39% in the 180-nm CMOS technology. Experimental results show that the circuit operates at supply voltages down to 800 mV and achieves an overall dynamic range of more than 140 dB. The power consumption at 800 mV supply and room light intensity is approximately 2.85 nW. (C) 2016 Elsevier B.V. All rights reserved.

  • 35.
    Ledin, Staffan
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems.
    A Comparison of Radix-2 Square Root Algorithms Using Digit Recurrence2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    When designing an electronic system, it might be desirable to implement a custom square root calculator unit to ensure quick calculations. The different questions when it comes to square root units are many. What algorithms are there? How are these algorithms implemented? What are the benefits and disadvantages of the different implementations? The goal of this thesis work is to try to answer these questions. In this paper, several different methods of calculating the radix-2 square root by digit recurrence are studied, designed and compared. The three main algorithms that are studied are the restoring square root algorithm, the non-restoring square root algorithm and the SRT (Sweeney, Robertson, Tocher) square root algorithm. They are all designed using the same technology and identical components where applicable. This is done in order to ensure that the comparisons give a fair assessment of the viability of the different algorithms. It is shown that the restoring and non-restoring square root algorithms perform similarly when using 65 nm technology, a 16 bit input, full data rate and 1.2 V power supply. The restoring square root algorithm have a slight edge when the systems are not pipelined, while the non-restoring algorithm performs slightly better when the systems are fully pipelined. The SRT square root algorithm perform worse than the other two in all cases.

  • 36.
    Lesen, Eva
    et al.
    Nordic School for Public Health.
    Sandstrom, Tatiana Z
    Nordic School for Public Health.
    Carlsten, Anders
    Medical Prod Agency.
    Jönsson, Anna K
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pharmacology.
    Mardby, Ann-Charlotte
    University of Gothenburg.
    Andersson Sundell, Karolina
    Nordic School for Public Health.
    A comparison of two methods for estimating refill adherence to statins in Sweden: the RARE project2011In: Pharmacoepidemiology and Drug Safety, ISSN 1053-8569, E-ISSN 1099-1557, Vol. 20, no 10, 1073-1079 p.Article in journal (Refereed)
    Abstract [en]

    Purpose To analyse and compare refill adherence to statins estimated with two different methods with a focus on sensitivity to definitions. less thanbrgreater than less thanbrgreater thanMethods Individuals aged 18-85 years who filled a statin prescription for the first time in 1.5 years during 1 January-30 June 2007 were followed until emigration or death or until 2 years after their first statin purchase. The data were collected via linkage between the Swedish Prescribed Drug Register, the National Patient Register and the Total Population Register. Days supply was estimated based on amount dispensed and prescribed dosage. Refill adherence was estimated with the continuous measure of medication acquisition (CMA) and the maximum gap method (cut-off 45days). The impact of altering definitions, for example, regarding hospitalisations, length of observation period and management of overlapping supply, was analysed. less thanbrgreater than less thanbrgreater thanResults The study included 36661 individuals (mean age 64 years, 47% women). The median proportion of days with statins was 95%, and 76% were classified as adherent with a cut-off at andgt;= 80% with CMA. With the maximum gap method, 65% were adherent. Disregarding hospitalisations did not alter the results. Emigration or death at least one year after statin initiation was associated with a lower adherence with both methods, and a shorter observation period and adding overlapping supply to the subsequent prescription increased the adherence estimates. less thanbrgreater than less thanbrgreater thanConclusions The choice of method and definitions, particularly regarding the management of overlapping supplies and the length of observation period, has a substantial impact on estimates of refill adherence to statins.

  • 37.
    Karlsson, Fredrik
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Moshfegh, Bahram
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    A comprehensive investigation of a low-energy building in Sweden2007In: Renewable Energy, ISSN 0960-1481, Vol. 32, no 11, 1830-1841 p.Article in journal (Refereed)
    Abstract [en]

    In Sweden, the building sector alone accounts for almost 40% of the total energy demand and people spend more than 80% of their time indoors. Reducing energy demand in the buildings is essential to the achievement of a sustainable built environment. At the same time, it is important to not deteriorate people's health, well-being and comfort in buildings. Thus, designing healthy and energy efficient buildings are one of the most challenging tasks for building scientists. A low-energy building that uses less than half of the purchased energy of a comparable typical Swedish building has been investigated from different viewpoints in an attempt to represent the building at different system levels. First, the ventilation performance in different rooms using the tracer gas method is reported. Second, results from simulations and in situ measurements are used to analyse the building's power demand and energy performance. The household's behaviour and their impact on energy usage as well as acceptance are reported. Finally, the CO2 emissions with regard to the energy usage are analysed on the basis of different supply energy forms from surrounding energy systems, for example a Swedish and European electricity mix, or district heating as a substitute for electrical heating.

  • 38.
    Svensson, Klas
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Rohdin, Patrik
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Moshfegh, Bahram
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    A computational parametric study on the development of confluent round jet arrays2015In: European journal of mechanics. B, Fluids, ISSN 0997-7546, E-ISSN 1873-7390, Vol. 53, 129-147 p.Article in journal (Refereed)
    Abstract [en]

    In this study, Computational Fluid Dynamics (CFD) and response surface methodology is employed in a parametrical investigation of an in-line array of confluent round jets. Confluent round jet arrays are common within several fields of engineering, as detailed knowledge of the flow field development of confluent round jets is of great importance to design engineers working with, for example, chemical mixing, multiple jet burners, waste water disposal systems or ventilation supply devices. In this paper, five independent factors affecting flow field development are investigated with a multi-variable approach using a Box–Behnken design method.

    The results include decay of maximum velocity, turbulence intensity, location of merging and combined points and development of volumetric flow rate. Dimensionless nozzle spacing, S/d0S/d0, is an important design parameter and has a large impact on several properties, such as merging and combined points, decay of maximum velocity, and development of turbulence intensity. Other factors, such as the number of jets per row and inlet velocity, are also of importance. The analysis of decay in maximum velocity led to the definition of a new zone of development, referred to as the Confluent Core Zone (CCZ), as its behaviour is reminiscent of the potential core of a single jet. The CCZ has uniform velocity, lacks considerable decay in streamwise velocity and has a rather low turbulence intensity. The CCZ has a characteristic footprint in confluent round jet arrays, and its properties are investigated in detail.

    The development of volumetric flow can be divided into two regions. The initial region, close to the nozzles, features a high entrainment but decreasing entrainment rate. As the jets combine, the entrainment rate is lower, but rather constant. While S/d0S/d0 is generally an important design parameter, there is no direct correlation between S/d0S/d0 and entrainment rate of the combined jet.

  • 39.
    Setijono, Djoko
    Linköping University, Department of Management and Engineering, Quality Technology and Management . Linköping University, The Institute of Technology.
    A conceptual framework for managing the performance of construction supply chain2009In: International Journal of Productivity and Quality Management, ISSN 1746-6474, Vol. 5, no 1, 1-20 p.Article in journal (Refereed)
    Abstract [en]

    This paper conceptualises four different states of the construction supply chain (fragmented supply markets, process integration, work clusters, and pools of suppliers) as the result of intersecting two strategic dimensions: industrial 'modes' (i.e. from project to process) and the extent of integration in which partnership exists (i.e. from less to highly integrated supply chain). Improvement methodologies such as TQM and lean thinking provide management philosophy, methods and tools to improve the performance of the construction supply chain towards its 'ideal' practice (value creation). Since benchmarking is an important mechanism for managing performance in the construction industry, the actors in a construction supply chain need to identify and develop relevant value-related (performance) measures and their impacts on gaining/maintaining partners' trust and their willingness to collaborate.

  • 40.
    Lakemond, Nicolette
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Project management, Innovations and Entrepreneurship .
    van Echtelt, F
    Wynstra, F
    A Configuration Typology for Involving Purchasing Specialists in Product Development2001In: ICFAI Journal of supply chain management, ISSN 0972-9267, Vol. 37, no 4, 11-27 p.Article in journal (Refereed)
    Abstract [en]

      

  • 41.
    Daneva, Maria
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mathematics, Optimization .
    Lindberg, Per Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Mathematics, Optimization .
    A Conjugate Direction Frank-Wolfe Method with Applications to the Traffic Assignment Problem2003In: Operations Research Proceedings 2002: Selected Papers of the International Conference on Operations Research (SOR 2002), Klagenfurt, September 2-5, 2002" / [ed] Leopold-Wildburger, U, Springer , 2003, -550 p.Chapter in book (Other academic)
    Abstract [en]

    This proceedings volume contains a selection of papers presented at the International Conference on Operations Research (SOR 2002).The contributions cover the broad interdisciplinary spectrum of Operations Research and present recent advances in theory, development of methods, and applications in practice. Subjects covered are Production, Logistics and Supply Chain Production, Marketing and Data Analysis, Transportation and Traffic, Scheduling and Project Management, Telecommunication and Information Technology, Energy and Environment, Public Economy, Health, Agriculture, Education, Banking, Finance, Insurance, Risk Management, Continuous Optimization, Discrete and Combinatorial Optimization, Stochastic and Dynamic Programming, Simulation, Control Theory, Systems Dynamics, Dynamic Games, Game Theory, Auctioning and Bidding, Experimental Economics, Econometrics, Statistics and Mathematical Economics, Fuzzy Logic, Multicriteria Decision Making, Decision Theory.

  • 42.
    Sharifimajd, Babak
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    A Continuum Framework for Modeling the Excitation–Contraction Coupling of Smooth Muscle2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Excitation-contraction coupling of smooth muscle refers to a chain of coupled physiological processes which convert a stimulus to a mechanical response. These processes can be disassociated into ionic transport during cell membrane excitation, activation of myosin light chains, and muscle contraction caused by actin-myosin interaction (filament sliding). This thesis concerns the development of a framework which allows to model the smooth muscle excitation-contraction coupling constitutively by applying the principle of virtual power and dissipation inequality. In doing so, the transport of ions through membrane channels is characterized by an ionic flux and an ionic supply, both governed by an electrochemical potential energy. By letting the Helmholtz free energy to be dependent on the myosin light chain configurations during contraction, the myosin light chain activation process, i.e., myosin phosphorylation, is included. The activation process links the membrane excitation to the filament sliding. A contractile element is presented to replicate the active deformation caused by the filament sliding within the smooth muscle cell. This deformation is coupled to the overall deformation of the muscle tissue by assuming a distinct principal alignment for the contractile elements.

    By employing this framework, an electro-chemo-mechanical model is derived by which the mechanical response of smooth muscle to an electrical stimulus is determined. This model is evaluated by comparing the model response to the experimental isometric stress data obtained from rat uterine smooth muscle tissue. By implementing this model in a finite element program, human uterine contractions during labor are simulated. This simulation determines important clinical factors, e.g., intrauterine pressure and provides the opportunity to investigate the effect of physiological and structural parameters on the uterine contractility.

    Finally, a methodology to accommodate individualized parameters from intrauterine pressure measurements is established. This methodology allows to develop models with potentials of being used clinically to diagnose difficulties during labor and delivery.

    List of papers
    1. A continuum model for skeletal muscle contraction at homogeneous finite deformations
    Open this publication in new window or tab >>A continuum model for skeletal muscle contraction at homogeneous finite deformations
    2013 (English)In: Biomechanics and Modeling in Mechanobiology, ISSN 1617-7959, E-ISSN 1617-7940, Vol. 12, no 5, 965-973 p.Article in journal (Refereed) Published
    Abstract [en]

    The contractile force in skeletal muscle models is commonly postulated to be the isometric force multiplied by a set of experimentally motivated functions which account for the muscle’s active properties. Although both flexible and simple, this approach does not automatically guarantee a thermodynamically consistent behavior. In contrast, the continuum mechanical model proposed herein is derived from fundamental principles in mechanics and guarantees a dissipative behavior. Further, the contractile force is associated with a friction clutch which provides a simple and well-defined macroscopic model for cycling cross-bridges. To show the performance of the model, it is specialized to standard experiments for rabbit tibialis anterior muscle. The results show that the model is able to capture important characteristics of skeletal muscle.

    Place, publisher, year, edition, pages
    Springer, 2013
    Keyword
    Skeletal muscle, Contractile element, Dissipation inequality, Strain-energy function, Continuum model
    National Category
    Other Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-85805 (URN)10.1007/s10237-012-0456-x (DOI)000324378900008 ()
    Funder
    Swedish Research Council
    Available from: 2012-11-28 Created: 2012-11-28 Last updated: 2015-09-02Bibliographically approved
    2. A continuum model for excitation–contraction of smooth muscle under finite deformations
    Open this publication in new window or tab >>A continuum model for excitation–contraction of smooth muscle under finite deformations
    2014 (English)In: Journal of Theoretical Biology, ISSN 0022-5193, E-ISSN 1095-8541, Vol. 355, 1-9 p.Article in journal (Refereed) Published
    Abstract [en]

    The main focus in most of continuum based muscle models is the muscle contraction dynamics while other physiological processes governing muscle contraction, e.g., the cell membrane excitation and the activation, are ignored. These latter processes are essential to initiate contraction and to determine the amount of generated force, and by excluding them, the developed model cannot replicate the true behavior of the muscle in question. The aim of this study is to establish a thermodynamically and physiologically consistent framework which allows to model smooth muscle contraction by including cell membrane excitability and kinetics of myosin phosphorylation, along with dynamics of smooth muscle contraction. The model accounts for these processes through a set of coupled dissipative constitutive equations derived by applying the first principles. To show the performance of the derived model, it is evaluated for two different cases: a mechanochemical study of pig taenia coli cells where the excitation process is excluded, and a complete excitation–contraction process of rat myometrium. The results show that the model is able to replicate important aspects of the smooth muscle EC process acceptably.

    Place, publisher, year, edition, pages
    Elsevier, 2014
    Keyword
    Smooth muscle excitation–contraction, Smooth muscle continuum model, The membrane model, Hodgkin-Huxley model, Hai-Murphy model
    National Category
    Other Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-100778 (URN)10.1016/j.jtbi.2014.03.016 (DOI)000337865100001 ()
    Available from: 2013-11-12 Created: 2013-11-12 Last updated: 2015-09-02Bibliographically approved
    3. Simulating uterine contraction by using an electro-chemo-mechanical model
    Open this publication in new window or tab >>Simulating uterine contraction by using an electro-chemo-mechanical model
    2016 (English)In: Biomechanics and Modeling in Mechanobiology, ISSN 1617-7959, E-ISSN 1617-7940, Vol. 15, no 3, 497-510 p.Article in journal (Refereed) Published
    Abstract [en]

    Contractions of uterine smooth muscle cells consist of a chain of physiological processes. These contractions provide the required force to expel the fetus from the uterus. The inclusion of these physiological processes is, therefore, imperative when studying uterine contractions. In this study, an electro-chemo-mechanical model to replicate the excitation, activation, and contraction of uterine smooth muscle cells is developed. The presented modeling strategy enables efficient integration of knowledge about physiological processes at the cellular level to the organ level. The model is implemented in a three-dimensional finite element setting to simulate uterus contraction during labor in response to electrical discharges generated by pacemaker cells and propagated within the myometrium via gap junctions. Important clinical factors, such as uterine electrical activity and intrauterine pressure, are predicted using this simulation. The predictions are in agreement with clinically measured data reported in the literature. A parameter study is also carried out to investigate the impact of physiologically related parameters on the uterine contractility.

    Place, publisher, year, edition, pages
    Springer, 2016
    Keyword
    Excitation-contraction model of uterine smooth muscle; Uterus contraction; Intrauterine pressure; Uterine electrical activity
    National Category
    Applied Mechanics
    Identifiers
    urn:nbn:se:liu:diva-121013 (URN)10.1007/s10237-015-0703-z (DOI)000376014800002 ()26162461 (PubMedID)
    Available from: 2015-09-02 Created: 2015-09-02 Last updated: 2016-06-13Bibliographically approved
    4. Identification of the mechanical parameters for the human uterus in vivo using intrauterine pressure measurements
    Open this publication in new window or tab >>Identification of the mechanical parameters for the human uterus in vivo using intrauterine pressure measurements
    2017 (English)In: International Journal for Numerical Methods in Biomedical Engineering, ISSN 2040-7939, E-ISSN 2040-7947, Vol. 33, no 1, 1-11 p.Article in journal (Refereed) Published
    Abstract [en]

    There are limited experimental data to characterize the mechanical response of human myometrium. A method is presented in this work to identify mechanical parameters describing the active response of human myometrium from the in vivo intrauterine pressure measurements. A finite element model is developed to compute the intrauterine pressure during labor in response to an increase in the intracellular calcium ion concentration within myometrial smooth muscle cells. The finite element model provides the opportunity to tune mechanical parameters in order to fit the computed intrauterine pressure to in vivo measurements. Since the model is computationally expensive, a cheaper meta-model is generated to approximate the model response. By fitting the meta-model response to the in vivo measurements, the parameters used to determine the active response of human myometrial smooth muscle are identified.

    Place, publisher, year, edition, pages
    John Wiley & Sons, 2017
    Keyword
    human uterine smooth muscle mechanics, intrauterine pressure, parameter identification, response surface methodology
    National Category
    Applied Mechanics Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-121014 (URN)10.1002/cnm.2778 (DOI)000393964900001 ()26915913 (PubMedID)2-s2.0-84962638845 (Scopus ID)
    Note

    At the time of the thesis presentation this publication was in status Manuscript.

    Available from: 2015-09-02 Created: 2015-09-02 Last updated: 2017-03-27Bibliographically approved
  • 43.
    Spiegler, Virginia L M
    et al.
    Cardiff University, Wales .
    Naim, Mohamed M
    Cardiff University, Wales .
    Wikner, Joakim
    Linköping University, Department of Management and Engineering, Production Economics. Linköping University, The Institute of Technology.
    A control engineering approach to the assessment of supply chain resilience2012In: International Journal of Production Research, ISSN 0020-7543, E-ISSN 1366-588X, Vol. 50, no 21, 6162-6187 p.Article in journal (Refereed)
    Abstract [en]

    There is no consensus on the supply chain management definition of resilience. To aid in evaluating the dynamic behaviour of such systems we need to establish clearly elucidated performance criteria that encapsulate the attributes of resilience. A literature review establishes the latter as readiness, responsiveness and recovery. We also identify robustness as a necessary condition that would complement resilience. We find that the Integral of the Time Absolute Error (ITAE) is an appropriate control engineering measure of resilience when it is applied to inventory levels and shipment rates. We use the ITAE to evaluate an often used benchmark model of make-to-stock supply chains consisting of three decision parameters. We use both linear and nonlinear forms of the model in our evaluation. Our findings suggest that optimum solutions for resilience do not yield a system that is robust to uncertainties in lead-time. Hence supply chains will experience drastic changes in their resilience performance when lead-time changes.

  • 44.
    Keshmiri, Vahid
    et al.
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, Faculty of Science & Engineering.
    Larsen, C.
    Umeå University, Sweden.
    Edman, L.
    Umeå University, Sweden.
    Forchheimer, Robert
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, Faculty of Science & Engineering.
    Tu, Deyu
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, Faculty of Science & Engineering.
    A Current Supply with Single Organic Thin-Film Transistor for Charging Supercapacitors2016In: THIN FILM TRANSISTORS 13 (TFT 13), ELECTROCHEMICAL SOC INC , 2016, Vol. 75, no 10, 217-222 p.Conference paper (Refereed)
    Abstract [en]

    We present a current supply, comprising a single organic thin-film transistor (OTFT), for the charging of supercapacitors. The current supply takes power from the electric grid (115 V AC, US standard), converts the AC voltage to a quasi-constant DC current (similar to 0.1 mA) regardless of the impedance of the load, and charges the supercapacitor. Solution-processed OTFTs based on the popular polymeric semiconductor poly(3-hexylthiophene- 2,5-diyl) have been developed to rectify the 115 V AC voltage. A diodeconfigured OTFT was used as a half-wave rectifier. The single OTFT current supply was demonstrated to charge a 220 mF supercapacitor to 1 V directly using 115 V AC voltage as the input. This work paves the road towards all-printable supercapacitor energy-storage systems with integrated chargers, which enable direct charging from a power outlet.

  • 45.
    Nilsson, Marcus
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Westring, Alexander
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A decision support system for an improved article placement2017Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Warehouse storage is an important part of a business’ supply chain. This is where articles temporary are stored before they either are carried on to the next step of the production or to be delivered to the customers of the company. The largest part of the stock keeping often devoted to the order picking. Order picking includes the activities that are occurring when an article is being picked from its stored position and is being transported to the next step of the flow of the materials. The most time- consuming part of the order picking process are often the time to pinpoint and to get the hold of an article. This implies quite likely that an enhancement of the productivity could be realized, inter alia, through cut the transport distances. SKF Mekan AB is an industrial corporation whose primary occupation is to manufacture bearing housings. Currently, the business has a flawed inventory for stock keeping. A great many of the articles stored in the inventory, entitled 104C, are placed in regard to their measures, without any thought in regard of how frequently the articles are picked. In addition, the article placement that is used today is outdated, which has resulted in that a lot of articles are lacking a specific placement in the inventory. The purpose of storing articles in the inventory 104C is to cope with fluctuations in the next step of the manufacturing, which is the processing factory. The aim of the study is to find out how the article placement looks in the current situation and how decisions concerning article placement are determined and what issues occurs due to this. A decision support system has been developed which purpose is to give SKF Mekan AB decision basis regarding where the different kinds of articles should be placed to attain an increased efficiency in business’ stock keeping. The decision support system is adaptable to the extent that the user can adjust the parameters that are determining the article placement. The study has been accomplished by means of observations and interviews. With the help of the observations, the layout of the warehouse and the article placement has been mapped out and with the help of the interviews; the results concerning work models and decision-making of article placement has been answered. Through the observations and the interviews appeared that 42.5 % of the stocked pallets were misplaced and that 15.6 % of the stocked pallets lacked a specific placement in the warehouse. This results in that the truck operators has a hard time localizing the pallets, which leads to inefficient labouring. This causes delays in the next step of the supply chain; i. e. the processing factory, meaning the personnel has to wait for the articles to be delivered. With the articles picking frequency and the principle of family grouping as point of reference for the article placement SKF Mekan AB should be able to eliminate non-value adding activities in the supply chain, which should lead to an increased potential of profitability.

  • 46.
    Ojani, Amin
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Mesgarzadeh, Behzad
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A DLL-based Injection-Locked Frequency Synthesizer for WiMedia UWB2012In: 2012 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS (ISCAS 2012), IEEE , 2012, 2027-2030 p.Conference paper (Refereed)
    Abstract [en]

    A WiMedia ultrawideband (UWB) frequency synthesizer is designed for band group #1. A very fast hopping is achieved by using a delay-locked loop (DLL) architecture which utilizes a novel variable gain voltage-controlled delay line (VCDL) scheme to compensate the phase error generated at the hopping instant. Fast-settling DLL allows an injection-locked oscillator (ILO) to be employed to reduce the current consumption in the edge combiner (EC). Simulated in STM 65-nm CMOS technology, synthesizer hopping time is less than two reference cycles. Phase noise at 3432 MHz is -124 dBc/Hz at 1 MHz offset. The adjacent spur level from the Monte Carlo simulation is -34 dBc. Excluding CML divider, the synthesizer draws 6.7 mW from a 1.2 V supply.

  • 47.
    Korishe, Abdulah
    Linköping University, Department of Electrical Engineering, Electronics System.
    A Driver Circuit for Body-Coupled Communication2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The main concept of Body-Coupled Communication (BCC) is to transmit the electrical information through the human body as a communication medium by means of capacitive coupling. Nowadays the current research of wireless body area network are expanding more with the new ideas and topologies for better result in respect to the low power and area, security, reliability and sensitivity since it is first introduced by the Zimmerman in 1995. In contrast with the other existing wireless communication technology such as WiFi, Bluetooth and Zigbee, the BCC is going to increase the number of applications as well as solves the problem with the cell based communication system depending upon the frequency allocation. In addition, this promising technology has been standardized by a task group named IEEE 802.15.6 addressing a reliable and feasible system for low power in-body and on-body nodes that serves a variety of medical and non medical applications.

    The entire BAN project is divided into three major parts consisting of application layer, digital baseband and analog front end (AFE) transceiver. In the thesis work a strong driver circuit for BCC is implemented as an analog front end transmitter (Tx). The primary purpose of the study is to transmit a strong signal as the signal is attenuated by the body around 60 dB. The Driver circuit is cascaded of two single-stage inverter and an identical inverter with drain resistor. The entire driver circuit is designed with ST65 nm CMOS technology with 1.2 V supply operated at 10 MHz frequency, has a driving capability of 6 mA which is the basic requirement. The performance of the transmitter is compared with the other architecture by integrating different analysis such as corner analysis, noise analysis and eye diagram. The cycle to cycle jitter is 0.87% which is well below to the maximum point and the power supply rejection ratio (PSRR) is 65 dB indicates the good emission of supply noise. In addition, the transmitter does not require a filter to emit the noise because the body acts like a low pass filter.

    In conclusion the findings of the thesis work is quite healthy compared to the previous work. Finally, there is some point to improve for the driver circuit in respect to the power consumption, propagation delay and leakage power in the future.   

  • 48.
    Wang, Qunzhi
    et al.
    Department of Industrial Engineering and Management Tokyo Institute of Technology.
    Tang, Ou
    Linköping University, The Institute of Technology. Linköping University, Department of Production Economics.
    Tsao, De-bi
    Department of Industrial Engineering and Management Tokyo Institute of Technology.
    A flexible contract strategy in a supply chain with an inflexible production mode2006In: International Journal of Operational Research, ISSN 1745-7645, Vol. 1, no 3, 228-248 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents a flexible supply contract with call options model for an inflexible supply chain, where the supplier only has an opportunity to produce one batch due to a long lead-time limitation. In such systems, there are eventually two decision points. At the beginning of the planning horizon, the supplier offers a wholesale price, and possibly also option purchasing and exercising prices. In addition to a firm initial order, the buyer can purchase options to adjust order quantity later. The supplier then determines the production volume. At the second decision point, with updated forecast, the buyer finalises the order quantity by exercising options. We formulate both the buyer's and the supplier's profit functions. Furthermore, we develop explicit expressions to determine the buyer's optimal decisions, and calculate the supplier's optimal decisions numerically. In numerical study, we illustrate that such a flexible contract strategy improves both the buyer's and supplier's profits. Copyright © 2006 Inderscience Enterprises Ltd.

  • 49.
    Klein, Richard
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, Faculty of Arts and Sciences. Stockholm Environment Institute, Sweden.
    Juhola, Sirkku
    University of Helsinki, Finland; Aalto University, Finland .
    A framework for Nordic actor-oriented climate adaptation research2014In: Environmental Science and Policy, ISSN 1462-9011, E-ISSN 1873-6416, Vol. 40, 101-115 p.Article in journal (Refereed)
    Abstract [en]

    The past ten years have seen a substantial increase in research on climate change adaptation, but a large gap remains between adaptation research and action. Adaptation researchers have either failed to demonstrate the relevance of their findings to practitioners and policymakers, or stakeholders have based their views and decisions on other kinds of information. In addition, in sectors such as agriculture, forestry, nature conservation, urban planning, water management and energy supply, adaptation has been studied separately from mitigation, which contradicts the reality of many practitioners. This paper identifies five bottlenecks to the use of adaptation research in adaptation practice and policy. These bottlenecks have gone unnoticed because the traditional framing of adaptation does not adequately consider the notion of agency, often rendering stakeholder interactions ineffective. Knowledge and use of actor-oriented theory when analysing and discussing adaptation needs and options could serve to find ways to overcome the bottlenecks and narrow the gap between research and action. The paper presents a novel framework for actor-oriented adaptation research that is being conducted within the Nordic Centre of Excellence for Strategic Adaptation Research (NORD-STAR). It frames climate adaptation as addressing both the impacts of climate change and the consequences of climate policy. Two methodological approaches - modelling and visualisation, and policy analysis - are applied to three thematic issues: land-use change, energy transitions, and insurance and finance.

  • 50.
    Noroozi, Sayeh
    Linköping University, Department of Management and Engineering, Production Economics. Linköping University, The Institute of Technology.
    A Framework for Sales and Operations Planning in Process Industries2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis studies Sales and Operations Planning (S&OP) in process industries. S&OP is a planning process which has a role of balancing demand and supply at an aggregate level. S&OP has traditionally been considered as a generic process meaning that it is independent from the context of the industry in which it is implemented. Process industries do; however, have specific characteristics which affect their planning and control processes, including S&OP. Therefore, the aim in this thesis is to reconcile these two contradictory stances and furthermore investigate how the specific properties in process industries should be included into an S&OP framework. Such a differentiated framework aims to support process industries to design/implement their S&OP process based on their unique requirements in relation to their markets, products and processes while it also takes into account the specific characteristics regarding the continuous production. Consequently, the process industries would realize the expected benefits from S&OP process to a greater extent.

    The study starts with a literature review on S&OP in process industries in order to build the knowledge foundation for subsequent studies. The results show that the underlying difference between process industries and discrete industries is the object continuity which affects the selection of production processes including resources. Thus, process industries are often hybrids in the sense that their production processes include both continuous production, when the transformed object (material) is continuous, and discrete production when the object (material) turns into discrete products after the discretization point. In other words, process industries deploy both continuous production and discrete production while discrete industries use only discrete production. The specific characteristics of process industries are actually related to the continuous production part and influence the planning processes as well. As the result of this study, the continuous production characteristics that can affect the S&OP process are identified.

    In the continuation of the thesis and in order to provide a typology for planning and control purposes, the object type (continuous and discrete) is combined with two other dimensions i.e. mode type (onetime, intermittent and continuous) and driver type (customer order driven and forecast driven) into a planning and control typology. The mode type addresses the repetitivity of the flow and the driver type takes into account the trigger of the flow. Each dimension has a transition point – i.e. the discretization point for the object type, mode interface point for the mode type and customer order decoupling point for the driver type – and represents a hybrid situation since different production environments are required before and after each transition point. The typology aims to illustrate how each dimension affects the planning and control issues as well as how the dimensions are interrelated and how this combination influence the managerial decisions. The typology integrates the concepts from both process industries and discrete industries and thus, is applicable for both.

    Thereafter the typology is applied to the S&OP process and an integrated framework is suggested based on the three dimensions with specific focus on process industries. In this framework, the effects of hybridities within each dimension and cross-hybridities between the dimensions on the S&OP process are also considered. The importance of hybridities and cross-hybridities lies in the fact that the planning of the hybrid systems is a complex task due to the varying managerial decisions before and after the transition points. Finally, implementation steps for the suggested S&OP framework are outlined for the process industries in order to position themselves in the framework, identify the implementing procedures, and obtain potential benefits based on the differentiated S&OP process.

    List of papers
    1. Sales and operations planning in the process industry: A literature review
    Open this publication in new window or tab >>Sales and operations planning in the process industry: A literature review
    2017 (English)In: International Journal of Production Economics, ISSN 0925-5273, E-ISSN 1873-7579, Vol. 188, 139-155 p.Article in journal (Refereed) Published
    Abstract [en]

    This paper provides a systematic literature review of Sales and Operations Planning (S&OP) in process industries. The aim is to investigate the present state of S&OP in process industries in comparison to discrete manufacturing industries and to identify the desired future state of the S&OP process based on the specific characteristics of process industries. The findings of this paper show that this issue has not received much attention in the academic world. Hence there is a need for conceptual models with focus on process industries’ specific characteristics. Process industries are actually hybrids of continuous production and discrete production (respectively, upstream and downstream of the discretization point) and the specific characteristics of process industries are related to the continuous production part. Thus, in this paper, the characteristics upstream of the discretization point are investigated and the integration of them in the S&OP process of the process industries is stressed.

    Place, publisher, year, edition, pages
    Elsevier, 2017
    Keyword
    Sales and operations planning, Process industry, Discretization point
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-106705 (URN)10.1016/j.ijpe.2017.03.006 (DOI)000401381300013 ()
    Note

    The original title in manuskript fiorm of this article was Sales and operations planning in the process industry.

    Funding agencies: Swedish Foundation for Strategic Research (SSF)

    Available from: 2014-05-19 Created: 2014-05-19 Last updated: 2017-06-13Bibliographically approved
    2. A modularised typology for flow design based on decoupling points - a holistic view on process industries and discrete manufacturing industries
    Open this publication in new window or tab >>A modularised typology for flow design based on decoupling points - a holistic view on process industries and discrete manufacturing industries
    2016 (English)In: Production planning & control (Print), ISSN 0953-7287, E-ISSN 1366-5871, Vol. 27, no 16, 1344-1355 p.Article in journal (Refereed) Published
    Abstract [en]

    Management of production activities covers a wide range of decisions. In this paper, a modularised approach is suggested that, through configuration, generates a case-specific flow design. The approach is based on identification of decision categories that are generic and fundamental in the flow design, covering both discrete manufacturing industries and process industries. Each decision category identifies a unique property of the flow which changes at a particular point: this is termed a decoupling point. A three-dimensional modularised typology is developed by combining three different decision categories. Cases from the steel industry and the tooling industry are used to illustrate how the typology can be applied. The modularised approach provides a typology for the application of both qualitative and quantitative methods for flow management, including planning, control and performance management.

    Place, publisher, year, edition, pages
    TAYLOR & FRANCIS LTD, 2016
    Keyword
    Typology; decoupling point; planning and control; process industry; modularisation
    National Category
    Production Engineering, Human Work Science and Ergonomics
    Identifiers
    urn:nbn:se:liu:diva-132245 (URN)10.1080/09537287.2016.1220649 (DOI)000384468200004 ()
    Note

    Funding Agencies|Swedish Foundation for Strategic Research [PIC-LI]; Process Industrial IT and Automation (PiiA) - VINNOVA; Swedish Energy Agency, Formas; Swedish industry [2014-05110]

    Available from: 2016-10-24 Created: 2016-10-21 Last updated: 2017-04-11
    3. A modularized framework for sales and operations planning with focus on process industries
    Open this publication in new window or tab >>A modularized framework for sales and operations planning with focus on process industries
    2016 (English)In: Production & Manufacturing Research, ISSN 2169-3277, Vol. 4, no 1, 65-89 p.Article in journal (Refereed) Published
    Abstract [en]

    This paper suggests a modularized sales and operations planning (S&OP) framework, consisting of content and process. The framework’s content is based on a typology of decoupling points in which the effect of decoupling points on the decision variables in S&OP is studied. The framework’s process takes a step back and addresses the need for a more elaborate design to precede the operational use of S&OP content for different production contexts. The framework supports both process industries (PIs) and discrete manufacturing industries (DIs), and recognizes their specific requirements and reflects them in their S&OP. The differentiating characteristics of PIs and DIs are emphasized through three different decoupling points, namely: discretization decoupling point, control mode decoupling point, and customer order decoupling point. The suggested framework aims to fill the gap in the literature regarding the lack of aggregate planning processes that match the PIs’ specific requirements by reflecting the differentiating characteristics of PIs in S&OP.

    Place, publisher, year, edition, pages
    Taylor & Francis, 2016
    National Category
    Economics and Business Other Mechanical Engineering Software Engineering
    Identifiers
    urn:nbn:se:liu:diva-133240 (URN)10.1080/21693277.2016.1200502 (DOI)
    Available from: 2016-12-15 Created: 2016-12-15 Last updated: 2017-04-11Bibliographically approved
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