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Angelakis, Vangelis
Alternative names
Publications (10 of 37) Show all publications
Matinrad, N., Andersson Granberg, T., Ennab Vogel, N. & Angelakis, V. (2019). Optimal Dispatch of Volunteers to Out-of-hospital Cardiac Arrest Patients. In: Proceedings of the 52nd Hawaii InternationalConference on System Sciences (HICSS), Hawaii, USA, 8th-11th January 2019: . Paper presented at The 52nd Hawaii InternationalConference on System Sciences (HICSS), Hawaii, USA, 8th-11th January 2019 (pp. 4088-4097). University of Hawai'i at Manoa
Open this publication in new window or tab >>Optimal Dispatch of Volunteers to Out-of-hospital Cardiac Arrest Patients
2019 (English)In: Proceedings of the 52nd Hawaii InternationalConference on System Sciences (HICSS), Hawaii, USA, 8th-11th January 2019, University of Hawai'i at Manoa , 2019, p. 4088-4097Conference paper, Published paper (Refereed)
Abstract [en]

Initiatives with mobile phone dispatched volunteers to out-of-hospital cardiac arrest (OHCA) cases, can be found today in some countries, e.g. Sweden, the Netherlands, Switzerland and Italy. When an OHCA case is reported, an alarm is sent to the registered volunteers’ phones. However, the allocation of which volunteers to send to the automatic external defibrillator (AED) and who to send directly to the patient, is today based on simple rules of thumb. In this paper, we propose a model to optimally select how many and which volunteers to send directly to the patient, and who should pick up and deliver an AED. The results show that the model can help increase the survivability of the patients, compared to simple decision rules.

Place, publisher, year, edition, pages
University of Hawai'i at Manoa, 2019
Keywords
Optimization of and the Use of IT for Healthcare Processes Information Technology in Healthcare Daily emergency, Mixed-integer optimization, Mobile dispatch, SMS life savers, Volunteer management
National Category
Medical Engineering
Identifiers
urn:nbn:se:liu:diva-155670 (URN)9780998133126 (ISBN)
Conference
The 52nd Hawaii InternationalConference on System Sciences (HICSS), Hawaii, USA, 8th-11th January 2019
Available from: 2019-03-25 Created: 2019-03-25 Last updated: 2019-05-28Bibliographically approved
Kosta, A., Pappas, N., Ephremides, A. & Angelakis, V. (2018). Age of Information and Throughput in a Shared Access Network with Heterogeneous Traffic. In: IEEE Global Telecommunications Conference (GLOBECOM), 2018, pp. 1-6.: . Paper presented at IEEE Global Telecommunications Conference (GLOBECOM).
Open this publication in new window or tab >>Age of Information and Throughput in a Shared Access Network with Heterogeneous Traffic
2018 (English)In: IEEE Global Telecommunications Conference (GLOBECOM), 2018, pp. 1-6., 2018Conference paper, Published paper (Refereed)
Abstract [en]

We consider a cognitive shared access scheme consisting of a high priority primary node and a low priority network with N secondary nodes accessing the spectrum. Assuming bursty traffic at the primary node, saturated queues at the secondary nodes, and multipacket reception capabilities at the receivers, we derive analytical expressions of the time average age of information of the primary node and the throughput of the secondary nodes. We formulate two optimization problems, the first aiming to minimize the time average age of information of the primary node subject to an aggregate secondary throughput requirement. The second problem aims to maximize the aggregate secondary throughput of the network subject to a maximum time average staleness constraint. Our results provide guidelines for the design of a multiple access system with multipacket reception capabilities that fulfills both timeliness and throughput requirements.

Series
IEEE Global Communications Conference ; 2018
Keywords
Throughput, Receivers, Information age, Delays, Aggregates, Queueing analysis
National Category
Electrical Engineering, Electronic Engineering, Information Engineering Telecommunications
Identifiers
urn:nbn:se:liu:diva-154649 (URN)10.1109/GLOCOM.2018.8647212 (DOI)000465774300065 ()978-1-5386-4727-1 (ISBN)978-1-5386-4728-8 (ISBN)
Conference
IEEE Global Telecommunications Conference (GLOBECOM)
Note

Funding agencies: European Unions Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant [642743]

Available from: 2019-02-25 Created: 2019-02-25 Last updated: 2019-06-28
Elshatshat, M. A., Papadakis, S. & Angelakis, V. (2018). Improving the Spectral Efficiency in Dense Heterogeneous Networks Using D2D-Assisted eICIC. In: 2018 IEEE 23rd International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD): . Paper presented at 2018 IEEE 23rd International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD), 17-19 Sept. 2018, Barcelona, Spain (pp. 32-37). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Improving the Spectral Efficiency in Dense Heterogeneous Networks Using D2D-Assisted eICIC
2018 (English)In: 2018 IEEE 23rd International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD), Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 32-37Conference paper, Published paper (Refereed)
Abstract [en]

Heterogeneous networks (HetNets) that consist of macro base stations (MBSs) and small base stations (SBSs) are a key architectural drive for achieving the high spectral efficiency (SE) in 5G and beyond. Moreover, device-to-device (D2D) communications underlaying mobile networks can provide reliable communications and add SE gains. A major challenge in HetNets is the inter-cell interference (ICI) due to the coexistence of multiple tiers of base stations (BSs). To tackle this challenge, the enhanced inter-cell interference coordination (eICIC) scheme was adopted by 3GPP. In eICIC the MBSs mute their transmission during the so-called ᅵalmost blank subframesᅵ (ABS). This muting strategy causes resources reduction to the MBS users (MUEs). We propose the use of D2D communications to forward the transmission from the SBS to the MUEs during ABS subframes, by using inactive UEs to relay the downlink transmission, when the destination UEs are outside the coverage of the BS. We use a heuristic resource allocation (RA) algorithm based on the traffic load at the SBSs that integrates eICIC with D2D communications to avoid the service degradation during the time-domain muting. Simulation results of a HetNet with D2D-eICIC show that the SE of our approach outperforms other interference management approaches.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
Series
International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD), ISSN 2378-4865, E-ISSN 2378-4873 ; 23
Keywords
Device-to-device communication;Relays;Interference;Downlink;Uplink;Base stations;Resource management;HetNets;D2D;SE;eICIC;ABS and RA
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-152765 (URN)10.1109/CAMAD.2018.8514945 (DOI)000454615800006 ()9781538661512 (ISBN)9781538661505 (ISBN)9781538661529 (ISBN)
Conference
2018 IEEE 23rd International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD), 17-19 Sept. 2018, Barcelona, Spain
Note

Funding agencies: European Unions Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant [642743]

Available from: 2018-11-20 Created: 2018-11-20 Last updated: 2019-01-21Bibliographically approved
Mohapatra, P., Pappas, N., Lee, J., Quek, T. Q. .. & Angelakis, V. (2018). Secure Communications for the Two-user Broadcast Channel with Random Traffic. IEEE Transactions on Information Forensics and Security, 13(9), 2294-2309
Open this publication in new window or tab >>Secure Communications for the Two-user Broadcast Channel with Random Traffic
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2018 (English)In: IEEE Transactions on Information Forensics and Security, ISSN 1556-6013, E-ISSN 1556-6021, Vol. 13, no 9, p. 2294-2309Article in journal (Refereed) Published
Abstract [en]

In this work, we study the stability region of the two-user broadcast channel (BC) with bursty data arrivals and security constraints. It is assumed that one of the receivers has a secrecy constraint, i.e., its packets need to be kept secret from the other receiver, which is defined based on SINR. The receiver with secrecy constraint has full-duplex capability to send a jamming signal for improving its service rate. The stability region of the two-user BC with secrecy constraint is characterized for the general decoding case. Then, assuming two different decoding schemes the respective stability regions are derived. The fullduplex operation of receiver results in self-interference, and the effect of imperfect self-interference cancelation on the stability region is also investigated. The stability region of the BC with a secrecy constraint, where the receivers do not have full duplex capability can be obtained as a special case of the results derived in this paper. In addition, the paper considers the problem of maximizing the saturated throughput of the queue for which there is no secrecy constraint under minimum service guarantees for the other queue. The results provide new insights on the effect of the secrecy constraint on the stability region of the BC. It is found that the stability region with secrecy constraint is sensitive to the degree of self-interference cancelation.

Place, publisher, year, edition, pages
IEEE Signal Processing Society, 2018
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-146030 (URN)10.1109/TIFS.2018.2818076 (DOI)000431896200013 ()
Funder
ELLIIT - The Linköping‐Lund Initiative on IT and Mobile Communications
Note

Funding agencies: National Research Foundation of Korea, Korea Government (MSIP) [2017R1C1B2009280]; DGIST Research and Development Program of the Ministry of Science and ICT [17-ST-02]; DGIST Research and Development Program of the Ministry of Science and ICT under ELLIIT

Available from: 2018-03-22 Created: 2018-03-22 Last updated: 2018-05-30Bibliographically approved
Kosta, A., Pappas, N. & Angelakis, V. (2017). Age of Information: A New Concept, Metric, and Tool. Boston - Delft: Now Publishers Inc.
Open this publication in new window or tab >>Age of Information: A New Concept, Metric, and Tool
2017 (English)Book (Refereed)
Abstract [en]

In an increasingly networked world in which information is becoming increasingly actual, how can a system know with certainty just how fresh the information on a remote system is? Much work has been done on delay or latency in systems, but only recently has the concept of the freshness of information in or about a system become quantifiable. This is termed the Age of Information.

Age of Information provides a whole new set of metrics and tools that can be used to characterize the freshness of information in communications, control and, indeed, information systems. In its early development, this monograph provides the reader with an easy-to-read tutorial-like introduction into this novel approach of dealing with information within systems. A critical summary of the work to date details the concept for the reader. A description of the fundamentals of the performance metrics is then presented before showing how the approach can be used as a tool in improving metrics in other contexts.

The survey and tutorial nature of this monograph will save any researcher or student considerable time in understanding the basics of Age of Information, which is destined to become an important research topic in networked systems.

Place, publisher, year, edition, pages
Boston - Delft: Now Publishers Inc., 2017. p. 110
Series
Foundations and Trends® in Networking, ISSN 1554-057X, E-ISSN 1554-0588 ; 12(3)
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-149022 (URN)10.1561/1300000060 (DOI)9781680833607 (ISBN)9781680833614 (ISBN)
Available from: 2018-06-25 Created: 2018-06-25 Last updated: 2019-05-09Bibliographically approved
Kosta, A., Pappas, N. & Angelakis, V. (2017). Age of Information: A New Concept, Metric, and Tool. Foundations and Trends in Networking, 12(3), 162-259
Open this publication in new window or tab >>Age of Information: A New Concept, Metric, and Tool
2017 (English)In: Foundations and Trends in Networking, ISSN 1554-057X, Vol. 12, no 3, p. 162-259Article in journal (Refereed) Published
Abstract [en]

Age of information (AoI) was introduced in the early 2010s as a notion to characterize the freshness of the knowledge a system has about a process observed remotely. AoI was shown to be a fundamentally novel metric of timeliness, significantly different, to existing ones such as delay and latency. The importance of such a tool is paramount, especially in contexts other than transport of information, since communication takes place also to control, or to compute, or to infer, and not just to reproduce messages of a source. This volume comes to present and discuss the first body of works on AoI and discuss future directions that could yield more challenging and interesting research.

Place, publisher, year, edition, pages
Deft: Now Publishers Inc., 2017
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-149054 (URN)10.1561/1300000060 (DOI)9781680833607 (ISBN)9781680833614 (ISBN)
Available from: 2018-06-26 Created: 2018-06-26 Last updated: 2019-05-09Bibliographically approved
Avgouleas, I., Pappas, N. & Angelakis, V. (2017). Scheduling Services on an IoT Device Under Time-Weighted Pricing. In: Conference Proceedings IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC): Workshop on "Communications for Networked Smart Cities". Paper presented at IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), Montreal, QC, Canada, October 08-13, 2017 (pp. 1-5). IEEE conference proceedings
Open this publication in new window or tab >>Scheduling Services on an IoT Device Under Time-Weighted Pricing
2017 (English)In: Conference Proceedings IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC): Workshop on "Communications for Networked Smart Cities", IEEE conference proceedings, 2017, p. 1-5Conference paper, Published paper (Refereed)
Abstract [en]

The emerging vision of smart cities necessitates the use of Internet of Things (IoT) network devices to implement sustainable solutions that will improve the operations of urban areas. A massive amount of smart cities services may demand allocation of computational resources, such as processing power or storage, that IoT devices offer. Within this context, we present an IoT network device comprising interfaces with one specific computational resource available. The efficient utilization of available IoT resources would improve the Quality of Service (QoS) of the IoT network that serves the smart city. All resource allocations must be completed within a given scheduling window and every service is parametrized by a pricing weight function to indicate its tolerance to be served at the beginning of the scheduling window. We propose a mathematical optimization formulation to minimize the total cost of allocating all demands within the scheduling window considering the tolerance level of each service at the same time. Moreover, we prove that the problem is computationally hard and we provide numerical results to gain insight into the impact of different pricing weight functions on the allocations’ distribution within the scheduling window.

Place, publisher, year, edition, pages
IEEE conference proceedings, 2017
Series
Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), E-ISSN 2166-9589 ; 2017
National Category
Telecommunications Communication Systems
Identifiers
urn:nbn:se:liu:diva-140105 (URN)10.1109/PIMRC.2017.8292656 (DOI)000426970903002 ()9781538635292 (ISBN)9781538635315 (ISBN)9781538635308 (ISBN)9781538635322 (ISBN)
Conference
IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), Montreal, QC, Canada, October 08-13, 2017
Funder
EU, FP7, Seventh Framework Programme
Available from: 2017-08-29 Created: 2017-08-29 Last updated: 2019-05-10Bibliographically approved
Li, Y., Pappas, N., Angelakis, V., Pioro, M. & Yuan, D. (2016). On the Resilient Network Design of Free Space Optical Wireless Network for Cellular Backhauling. In: Murat Uysal, Carlo Capsoni, Zabih Ghassemlooy, Anthony Boucouvalas, Eszter Udvary (Ed.), Optical Wireless Communications: (pp. 485-510). Springer
Open this publication in new window or tab >>On the Resilient Network Design of Free Space Optical Wireless Network for Cellular Backhauling
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2016 (English)In: Optical Wireless Communications / [ed] Murat Uysal, Carlo Capsoni, Zabih Ghassemlooy, Anthony Boucouvalas, Eszter Udvary, Springer, 2016, p. 485-510Chapter in book (Refereed)
Abstract [en]

With the densification of nodes in cellular networks, free space optics (FSO) connections are becoming an appealing low cost and high rate alternative to copper and fiber backhaul solutions for wireless communication systems. To en- sure a reliable cellular backhaul, provisions for redundant, disjoint paths between the nodes must be made in the design phase. This chapter aims at finding a cost- effective solution to upgrade the cellular backhaul with pre-deployed optical fibers using FSO links and mirror components. A novel integer linear programming model to approach optimal FSO backhaul design, guaranteeing K-disjoint paths connecting each node pair is presented. Next, a column generation method to a path-oriented mathematical formulation is developed. Applying the method in a sequential man- ner enables high computational scalability. Realistic scenarios are used to demon- strate the proposed approaches which efficiently provide optimal or near-optimal solutions, and thereby allow for accurately dealing with the trade-off between cost and reliability. 

Place, publisher, year, edition, pages
Springer, 2016
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-143277 (URN)10.1007/978-3-319-30201-0_22 (DOI)978-3-319-30201-0 (ISBN)
Projects
EU Marie Curie Actions project SOrBet (FP7-PEOPLE- 2013-IAPP: 612361)COST Action IC1101 OPTICWISE (Optical Wireless Communications – An Emerging Technology)European FP7 Marie Curie IOF project 329313
Available from: 2017-11-29 Created: 2017-11-29 Last updated: 2017-12-06Bibliographically approved
He, Q., Angelakis, V., Ephremides, A. & Yuan, D. (2016). Polynomial Complexity Minimum-Time Scheduling in a Class of Wireless Networks. IEEE Transactions on Control of Network Systems, 3(3), 322-331
Open this publication in new window or tab >>Polynomial Complexity Minimum-Time Scheduling in a Class of Wireless Networks
2016 (English)In: IEEE Transactions on Control of Network Systems, ISSN 2325-5870, Vol. 3, no 3, p. 322-331Article in journal (Other academic) Published
Abstract [en]

We consider a wireless network with a set of transmitter-receiver pairs, or links, that share a common channel, and address the problem of emptying finite traffic volume from the transmitters in minimum time. This, so called, minimum-time scheduling problem has been proved to be NP-hard in general. In this paper, we study a class of minimum-time scheduling problems in which the link rates have a particular structure. We show that global optimality can be reached in polynomial time and derive optimality conditions. Then we consider a more general case in which we apply the same approach and obtain an approximation as well as lower and upper bounds to the optimal solution. Simulation results confirm and validate our approach.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2016
Keywords
algorithm, interference, optimality, scheduling, wireless networks
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-112446 (URN)10.1109/TCNS.2015.2512678 (DOI)000384701100010 ()
Note

At the time for thesis presentation publication was in status: Manuscript

Available from: 2014-11-27 Created: 2014-11-27 Last updated: 2019-07-15Bibliographically approved
Pappas, N., Gunnarsson, J., Kratz, L., Kountouris, M. & Angelakis, V. (2015). Age of Information of Multiple Sources with Queue Management. In: 2015 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC): . Paper presented at IEEE International Conference on Communications (ICC) (pp. 5935-5940). IEEE
Open this publication in new window or tab >>Age of Information of Multiple Sources with Queue Management
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2015 (English)In: 2015 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC), IEEE , 2015, p. 5935-5940Conference paper, Published paper (Refereed)
Abstract [en]

We consider a system of multiple sources generating status update packets, which need to be sent by a single transmitter to a destination over a network. In the model we study, the packet generation time may vary at each source, and the packets go through the network with a random delay. Each update carries a time stamp of its generation, allowing the destination to calculate for each source the so called Age of Information, which measures the timeliness of each status update arriving. Considering that queuing delay can unnecessarily increase the age of a critical status update, we propose here a queue management technique, in which we maintain a queue with only the latest status packet of each source, overwriting any previously queued update from that source. This simple technique drastically limits the need for buffering and can be applied in systems where the history of source status is not relevant. We show that this scheme results in significantly less transmissions compared to the standard M/M/1 queue model. Furthermore, the proposed technique reduces the per source age of information, especially in settings not using queue management with high status update generation rates.

Place, publisher, year, edition, pages
IEEE, 2015
Series
IEEE International Conference on Communications, ISSN 1550-3607
National Category
Civil Engineering
Identifiers
urn:nbn:se:liu:diva-127295 (URN)10.1109/ICC.2015.7249268 (DOI)000371708106026 ()978-1-4673-6432-4 (ISBN)
Conference
IEEE International Conference on Communications (ICC)
Available from: 2016-04-20 Created: 2016-04-19 Last updated: 2019-05-09
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