Mihaela Mitici

Graduate of the Stochastic Operations Group, Department of Applied Mathematics

Contact:
E-mail: m.a.mitici’at’utwente.nl
Phone: +31 53 489 3040

 

 

 

 

 

 

Abstract thesis (download)

“Performance analysis of data retrieval in wireless sensor networks”

In this thesis, we employ the theory of stochastic processes and queueing, combinatorial theory, stochastic dynamic programing to analyze the performance of wireless sensor networks, with a focus on data retrieval time, energy consumption and measurement reliability constraints.

Firstly, we analyze the time needed to retrieve a fixed number of sensor measurements from a wireless sensor network. Based on these measurements, an aggregate is obtained. We take into account aspects such as transmission interference, limited, stochastic energy availability induced by the fact that the sensors harvest energy from the environment, limited transmission bandwidth. We analyze the retrieval time of measurements under centralized and decentralized sensor transmission schedules. The degree of difference between the two types of schedules, which we derive in this thesis, indicates the degree of improvement that distributed schedules can achieve.

Secondly, we consider wireless caches, randomly deployed in the plane, that store a data file in a distributed manner. We provide an exact characterization of the Pareto front of two conflicting objectives concerning the cost of deploying the caches in the plane and the energy cost of retrieving the data file from these caches. We analyze the Pareto front under a partitioning and a network coding data caching strategy. Pareto dominance is proven for the network coding strategy.

Thirdly, we consider the case where sensed data is retrieved by querying either the sensor network or a central database. We formulate an optimal query processing strategy with respect to the response time of queries and the quality (freshness) of the query data. We employ a discrete-time Markov decision process, which is derived by non-standard, exponential uniformization of a continuous-time Markov decision process with a drift. We compare numerically the performance of this optimal policy with several heuristics, and show under which system parameters these heuristics perform close to the optimal with respect to the query response time and data quality.

The results derived in this thesis aim to provide a formal, theoretical support for the design of wireless sensor network applications related to the retrieval of reliable data, with a goal of assisting the implementation of such applications.

Research interests:

·

Data retrieval and compression in wireless sensor networks

·

Network Coding

·

Scheduling

·

Random graphs

Publications:

·

M. Mitici, M. Onderwater, M. de Graaf, J. van Ommeren, N. van Dijk, J. Goseling, and R.J. Boucherie, Optimal Query Assignment for Wireless Sensor Networks, AEUE International Journal of Electronics and Communications, vol. 69, pages 1102-1112, 2015. pdf

·

Mitici, Jasper Goseling, Maurits de Graaf and Richard J. Boucherie, Decentralized vs. Centralized Scheduling in Wireless Sensor Networks For Data Fusion, In Proceedings of the 39th IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Florence, 2014. pdf

·

Mihaela Mitici, Jasper Goseling, Maurits de Graaf and Richard J. Boucherie, Energy-Delay Trade-off of Wireless Data Collection in the Plane, In Proceedings of the 4th joint WIC/IEEE SP Symposium on Information Theory and Signal Processing in the Benelux, Eindhoven, 2014. pdf

·

M. Mitici, J. Goseling, M. de Graaf, and R.J. Boucherie, Deployment versus data retrieval costs for caches in the plane, IEEE Wireless Communications Letters, vol. 3, pages 385-388, 2014. pdf

·

M. Mitici, J. Goseling, M. de Graaf, and R.J. Boucherie, Optimal Deployment of Caches in the Plane, In Proceedings of IEEE Global Conference on Signal and Information Processing, pages 863-866, 2013. pdf

·

Bansal, N., Bourne, D.P., Firat, M., Graaf, M. de, Kapodistria, S., Kumar, K., Meerman, C., Mitici, M., Nardi, F.R., Rijk, B. de, Sarswat, S. & Scardia, L. (2013). Optimization of lifetime in sensor networks. In M.A.A. Boon (Ed.), Conference Paper: Proceedings of the 84th European Study Group Mathematics with Industry (SWI 2012), (pp. 39-69).

Conference and Seminar Presentations

·

4th joint WIC/IEEE SP Symposium on Information Theory and Signal Processing in the Benelux, Eindhoven, The Netherlands, May 2014.

·

37th Dutch National Operations Research Conference, Lunteren, The Netherlands,January 2013.

Posters

·

39th International Conference on Acoustics, Speech and Signal Processing, Florence, Italy, May 2014.

·

1st IEEE Global Conference on Signal and Information Processing, Texas, USA, December 2013.

·

ICT.Open, Rotterdam,The Netherlands, October 2012.

·

Intelligent Sensor Networks (ISN), Apeldoorn, October 2012.

Teaching activities

·

Teaching assistant, Stochastic Processes: Renewal Processes, Martingales, Branching Processes, Brownian Motion, Master course, Fall 2014.

·

Teaching assistant, Stochastic Processes, Master course, Fall 2013.

Awards

·

Best Presentation Award at the 4th joint WIC/IEEE SP Symposium on Information Theory and Signal Processing in the Benelux, May 2014.

·

“Open Horizons” scholarship for MSc in Operations Research at University of Amsterdam, Bucharest, Romania, 2010-2011.

SYMPOSIUM