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Amirijoo, Mehdi
Publications (10 of 24) Show all publications
Zhao, Y., Yin, F., Gunnarsson, F., Amirijoo, M. & Hendeby, G. (2016). Gaussian Process for Propagation modeling and Proximity Reports Based Indoor Positioning. In: 2016 IEEE 83rd Vehicular Technology Conference (VTC Spring): . Paper presented at 2016 IEEE 83rd Vehicular Technology Conference: VTC2016-Spring, 15–18 May 2016, Nanjing, China (pp. 1-5). IEEE
Open this publication in new window or tab >>Gaussian Process for Propagation modeling and Proximity Reports Based Indoor Positioning
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2016 (English)In: 2016 IEEE 83rd Vehicular Technology Conference (VTC Spring), IEEE , 2016, p. 1-5Conference paper, Published paper (Refereed)
Abstract [en]

The commercial interest in proximity services is increasing. Application examples include location-based information and advertisements, logistics, social networking, file sharing, etc. In this paper, we consider network-based positioning based on times series of proximity reports from a mobile device, either only a proximity indicator, or a vector of RSS from observed nodes. Such positioning corresponds to a latent and nonlinear observation model. To address these problems, we combine two powerful tools, namely particle filtering and Gaussian process regression (GPR) for radio signal propagation modeling. The latter also provides some insights into the spatial correlation of the radio propagation in the considered area. Radio propagation modeling and positioning performance are evaluated in a typical office area with Bluetooth-Low-Energy (BLE) beacons deployed for proximity detection and reports. Results show that the positioning accuracy can be improved by using GPR.

Place, publisher, year, edition, pages
IEEE, 2016
National Category
Communication Systems
Identifiers
urn:nbn:se:liu:diva-128255 (URN)10.1109/VTCSpring.2016.7504255 (DOI)000386528400206 ()9781509016983 (ISBN)
Conference
2016 IEEE 83rd Vehicular Technology Conference: VTC2016-Spring, 15–18 May 2016, Nanjing, China
Available from: 2016-05-24 Created: 2016-05-24 Last updated: 2019-02-12Bibliographically approved
Kang, W., Son, S. H., Stankovic, J. A. & Amirijoo, M. (2008). I/O-Aware Deadline Miss Ratio Management in Real-Time Embedded Databases. In: IEEE Real-Time Systems Symposium,2008: . Paper presented at Real-Time Systems Symposium. USA: IEEE
Open this publication in new window or tab >>I/O-Aware Deadline Miss Ratio Management in Real-Time Embedded Databases
2008 (English)In: IEEE Real-Time Systems Symposium,2008, USA: IEEE , 2008Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
USA: IEEE, 2008
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-41071 (URN)10.1109/RTSS.2007.19 (DOI)55037 (Local ID)978-0-7695-3062-8 (ISBN)55037 (Archive number)55037 (OAI)
Conference
Real-Time Systems Symposium
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2018-01-13
Amirijoo, M., Gunnarsson, S., Hansson, J. & Son, S. H. (2008). Quantifying and Suppressing the Measurement Disturbance in Feedback Controlled Real-Time Systems. Real-time systems, 40(1), 44-76
Open this publication in new window or tab >>Quantifying and Suppressing the Measurement Disturbance in Feedback Controlled Real-Time Systems
2008 (English)In: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, Vol. 40, no 1, p. 44-76Article in journal (Refereed) Published
Abstract [en]

In the control of continuous and physical systems, the controlled system is sampled sufficiently fast to capture the dynamics of the system. In general, this property cannot be applied to the control of computer systems as the measured variables are often computed over a data set, e.g., deadline miss ratio. In this paper we quantify the disturbance present in the measured variable as a function of the data set size and the sampling period, and we propose a feedback control structure that suppresses the measurement disturbance. The experiments we have carried out show that a controller using the proposed control structure outperforms a traditional control structure with regard to performance reliability.

Place, publisher, year, edition, pages
Springer, 2008
Keywords
Adaptive scheduling, Feedback control, Measurement disturbance, System disturbance
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-12639 (URN)10.1007/s11241-008-9048-3 (DOI)
Available from: 2007-10-17 Created: 2007-10-17 Last updated: 2017-12-14
Tesanovic, A., Amirijoo, M., Nilsson, D., Norin, H. & Hansson, J. (2007). Dynamically Reconfigurable QoS-aware Embedded Systems (2ed.). In: Raj Kamal (Ed.), Embedded Systems: Status and Perspective: . USA: American Scientific Publisher
Open this publication in new window or tab >>Dynamically Reconfigurable QoS-aware Embedded Systems
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2007 (English)In: Embedded Systems: Status and Perspective / [ed] Raj Kamal, USA: American Scientific Publisher , 2007, 2, p. -633Chapter in book (Other academic)
Abstract [en]

This book, equally applicable for a CSE or ECE course, gives an extensive account of Embedded Systems, keeping a balanced coverage of hardware and software concepts. Adhering to syllabus needs, this title is ‘microprocessor’ and ‘software design methodology’ specific, giving due weightage to architecture, programming and design aspects.

Place, publisher, year, edition, pages
USA: American Scientific Publisher, 2007 Edition: 2
Keywords
Embedded system, QoS, reconfigurable system
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-38144 (URN)41945 (Local ID)978-0-07-340456-1 (ISBN)0-07-340456-X (ISBN)41945 (Archive number)41945 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2018-01-13Bibliographically approved
Amirijoo, M., Hansson, J., Son, S. H. & Gunnarsson, S. (2007). Experimental Evaluation of Linear Time-Invariant Models for Feedback Performance Control in Real-Time Systems. Real-time systems, 35(3), 209-238
Open this publication in new window or tab >>Experimental Evaluation of Linear Time-Invariant Models for Feedback Performance Control in Real-Time Systems
2007 (English)In: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, Vol. 35, no 3, p. 209-238Article in journal (Refereed) Published
Abstract [en]

In recent years a new class of soft real-time applications operating in unpredictable environments has emerged. Typical for these applications is that neither the resource requirements nor the arrival rates of service requests are known or available a priori. It has been shown that feedback control is very effective to support the specified performance of dynamic systems that are both resource insufficient and exhibit unpredictable workloads. To efficiently use feedback control scheduling it is necessary to have a model that adequately describes the behavior of the system. In this paper we experimentally evaluate the accuracy of four linear time-invariant models used in the design of feedback controllers. We introduce a model (DYN) that captures additional system dynamics, which a previously published model (STA) fails to include. The accuracy of the models are evaluated by validating the models with regard to measured data from the controlled system and through a set of experiments where we evaluate the performance of a set of feedback control schedulers tuned using these models. From our evaluations we conclude that second order models (e.g., DYN) are more accurate than first order models (e.g. STA). Further we show that controllers tuned using second order models perform better than controllers tuned using first order models.

Place, publisher, year, edition, pages
Springer Science+Business Media B.V., 2007
Keywords
Feedback control scheduling, Modeling, Model validation, System identification
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-12636 (URN)10.1007/s11241-006-9008-8 (DOI)
Available from: 2007-10-17 Created: 2007-10-17 Last updated: 2017-12-14
Amirijoo, M., Son, S. H. & Hansson, J. (2007). QoD Adaptation for Achieving Lifetime Predictability of WSN Nodes Communicating over Satellite Links. In: International Conference on Networked Sensing Systems INSS,2007: . Paper presented at Networked Sensing Systems (pp. 19-26). IEEE
Open this publication in new window or tab >>QoD Adaptation for Achieving Lifetime Predictability of WSN Nodes Communicating over Satellite Links
2007 (English)In: International Conference on Networked Sensing Systems INSS,2007, IEEE , 2007, p. 19-26Conference paper, Published paper (Refereed)
Abstract [en]

In this paper we propose an architecture consisting of a particular type of node, namely a communication server that collects and aggregates data, and establishes a link between the users and the sensor nodes through satellite communication. A key challenge with satisfying a lifetime requirement of the communication server is the unpredictability of the sensor data volume arriving at the communication server and the transmission power of the satellite terminal. To provide lifetime predictability we propose an approach that automatically adjusts the quality of the data such that the specified lifetime if achieved. We have shown through an extensive evaluation that the approach manages to provide an actual lifetime within 2% of the specified lifetime despite variations in workload and communication link quality.

Place, publisher, year, edition, pages
IEEE, 2007
Keywords
wireless sensor network
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-37483 (URN)10.1109/INSS.2007.4297382 (DOI)36167 (Local ID)1-4244-1231-5 (ISBN)36167 (Archive number)36167 (OAI)
Conference
Networked Sensing Systems
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2018-01-13
Amirijoo, M. (2007). QoS Control of Real-Time Data Services under Uncertain Workload. (Doctoral dissertation). : Institutionen för datavetenskap
Open this publication in new window or tab >>QoS Control of Real-Time Data Services under Uncertain Workload
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Real-time systems comprise computers that must generate correct results in a timely manner. This involves a wide spectrum of computing systems found in our everyday life ranging from computers in rockets to our mobile phones. The criticality of producing timely results defines the different types of realtime systems. On one hand, we have the so-called hard real-time systems, where failing to meet deadlines may result in a catastrophe. In this thesis we are, however, concerned with firm and soft real-time systems, where missing deadlines is acceptable at the expense of degraded system performance. The usage of firm and soft real-time systems has increased rapidly during the last years, mainly due to the advent of applications in multimedia, telecommunication, and e-commerce. These systems are typically data-intensive, with the data normally spanning from low-level control data, typically acquired from sensors, to high-level management and business data. In contrast to hard real-time systems, the environments in which firm and soft real-time systems operate in are typically open and highly unpredictable. For example, the workload applied on a web server or base station in telecommunication systems varies according to the needs of the users, which is hard to foresee. In this thesis we are concerned with quality of service (QoS) management of data services for firm and soft real-time systems. The approaches and solutions presented aim at providing a general understanding of how the QoS can be guaranteed according to a given specification, even if the workload varies unpredictably. The QoS specification determines the desired QoS during normal system operation, and the worst-case system performance and convergence rate toward the desired setting in the face of transient overloads. Feedback control theory is used to control QoS since little is known about the workload applied on the system. Using feedback control the difference between the measured QoS and the desired QoS is formed and fed into a controller, which computes a change to the operation of the real-time system. Experimental evaluation shows that using feedback control is highly effective in managing QoS such that a given QoS specification is satisfied. This is a key step toward automatic management of intricate systems providing real-time data services.

Place, publisher, year, edition, pages
Institutionen för datavetenskap, 2007. p. 244
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1143
Keywords
real-time system, database, feedback control
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-10016 (URN)978-91-85895-49-6 (ISBN)
Public defence
2007-11-15, Planck, Fysikhuset, Linköpings universitet, 13:15 (English)
Opponent
Supervisors
Available from: 2007-10-17 Created: 2007-10-17 Last updated: 2018-01-13
Amirijoo, M., Brännström, P., Hansson, J., Gunnarsson, S. & Son, S. (2007). Toward Adaptive Control of QoS-Importance Decoupled Real-Time Systems. In: IEEE International Workshop on Feedback Control Implementation and Design in Computing Systems and Networks,2007.
Open this publication in new window or tab >>Toward Adaptive Control of QoS-Importance Decoupled Real-Time Systems
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2007 (English)In: IEEE International Workshop on Feedback Control Implementation and Design in Computing Systems and Networks,2007, 2007Conference paper, Published paper (Refereed)
Abstract [en]

This paper deals with differentiated services in real-time systems. Tasks submitted to a real-time system are differentiated with respect to importance and QoS requirements. We use feedback control to enforce the requirements in QoS and ensure a hierarchical admission policy based on the importance of the tasks. The results show that the requirements are met during steady state when the workload is constant. The feedback control approach does not satisfactorily manage QoS when there is a sudden and significant workload change (transient state) due to the time-variant nature of the system. To address this, we present preliminary and promising results using adaptive control, and report on some challenges we are facing when applying the theory.

Keywords
real-time system, quality of service, QoS, control theory, system identification, differentiated services
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-38143 (URN)41926 (Local ID)41926 (Archive number)41926 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2018-01-13
Larsson, E., Amirijoo, M., Karlsson, D. & Eles, P. I. (2007). What Impacts Course Evaluation?. In: 12th SIGCSE Conf. on Innovation and Technology in Computer Science Education,2007: . Paper presented at 12th SIGCSE Conf. on Innovation and Technology in Computer Science Education,2007 (pp. 333-333).
Open this publication in new window or tab >>What Impacts Course Evaluation?
2007 (English)In: 12th SIGCSE Conf. on Innovation and Technology in Computer Science Education,2007, 2007, p. 333-333Conference paper, Published paper (Refereed)
Abstract [en]

Today most universities are using course evaluations. However, course evaluations are often discussed and questioned. This paper reports on a survey where we aim at finding out (1) if students have a preconceived notion of a course, (2) if course evaluation scores can be predicted early in a course, (3) if exam throughput impacts course evaluation, and (4) if web-based evaluation reflects the general opinion from students. The results from the study indicate that students do not let preconceived notion impact nor does exam throughput matter to course evaluation. Further, the final web-based results seem to correlate with opinion of students attending lectures. However, the evaluation grades tend to be defined early in the course; hence first impression lasts.

Keywords
education, computer science, course evaluation
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-39297 (URN)10.1145/1268784.1268901 (DOI)47830 (Local ID)978-1-59593-610-3 (ISBN)47830 (Archive number)47830 (OAI)
Conference
12th SIGCSE Conf. on Innovation and Technology in Computer Science Education,2007
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2018-01-13
Amirijoo, M., Tesanovic, A., Andersson, T., Hansson, J. & Son, S. H. (2006). Finite Horizon QoS Prediction of Reconfigurable Firm Real-Time Systems. In: IEEE International Conference on Embedded and Real-Time Computing Systems and Applications,2006 (pp. 233). Los Alamitos, California, USA: IEEE Computer Society
Open this publication in new window or tab >>Finite Horizon QoS Prediction of Reconfigurable Firm Real-Time Systems
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2006 (English)In: IEEE International Conference on Embedded and Real-Time Computing Systems and Applications,2006, Los Alamitos, California, USA: IEEE Computer Society , 2006, p. 233-Conference paper, Published paper (Refereed)
Abstract [en]

Updating real-time system software is often needed in response to errors and added requirements to the software. Stopping a running application, updating the software, and then restarting the application is not suitable for systems with high availability requirements. On the other hand, dynamically updating a system may increase the execution time of the tasks, thus, degrading the performance of the system. Degradation is not acceptable for performance-critical real-time systems as there are strict requirements on the performance. In this paper we present an approach that enables dynamic reconfiguration of a real-time system, where the performance of the system during a reconfiguration satisfies a given worst-case performance specification. Evaluation shows that the presented method is efficient in guaranteeing the worst-case performance of dynamically reconfigurable firm real-time systems. 

Place, publisher, year, edition, pages
Los Alamitos, California, USA: IEEE Computer Society, 2006
Keywords
Real-time system, modeling, feedback control, software engineering
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-34200 (URN)21000 (Local ID)21000 (Archive number)21000 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2018-01-13
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