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Stefan Unterschütz

Picture of Stefan Unterschütz
Dr.-Ing. Stefan Unterschütz

I studied at the Hamburg University of Technology and graduated in information technology (Informatik-Ingenieurwesen) in September 2009. Now I'm working as a research assistant at the Institute of Telematics.

Projects

Publications

Christian Renner, Stefan Unterschütz, Volker Turau and Kay Römer. Perpetual Data Collection with Energy-Harvesting Sensor Networks. ACM Transactions on Sensor Networks, 11(12):1–12, November 2014.
[BibTeX] [Abstract] [DOI]
@Article{Telematik_RUTR_2013_SCIS, author = {Christian Renner and Stefan Untersch{\"u}tz and Volker Turau and Kay R{\"o}mer}, title = {Perpetual Data Collection with Energy-Harvesting Sensor Networks}, pages = {1-12}, journal = {ACM Transactions on Sensor Networks}, volume = {11}, number = {12}, month = nov, year = 2014, }
Abstract: A sustainable, uniform, and utility-maximizing operation of energy-harvesting sensor networks requires methods for aligning consumption with harvest. This article presents a lightweight algorithm for online load adaptation of energy-harvesting sensor nodes using supercapacitors as energy buffers. The algorithm capitalizes on the elementary relationship between state of charge and voltage that is characteristic for supercapacitors. It is particularly designed to handle the nonlinear system model, and it is lightweight enough to run on low-power sensor node hardware. We define two energy policies, evaluate their performance using real-world solar-harvesting traces, and analyze the influence of the supercapacitor’s capacity and imprecisions in harvest forecasts. To show the practical merit of our algorithm, we devise a load adaptation scheme for multihop data collection sensor networks and run a 4-week field test. The results show that (i) choosing a duty cycle a priori is infeasible, (ii) our algorithm increases the achievable work load of a node when using forecasts, (iii) uniform and steady operation is achieved, and (iv) depletion can be prevented in most cases.
Stefan Unterschütz. Methodologies and Protocols for Wireless Communication in Large-Scale, Dense Mesh Networks. PhD Thesis, Hamburg University of Technology, Hamburg, Germany, 2014.
[BibTeX] [Abstract] [URL]
@PhdThesis{Telematik_Unterschuetz_2014_Diss, author = {Stefan Untersch{\"u}tz}, title = {Methodologies and Protocols for Wireless Communication in Large-Scale, Dense Mesh Networks}, publisher = {Cuvillier Verlag, G{\"o}ttingen, Germany}, school = {Hamburg University of Technology}, address = {Hamburg, Germany}, edition = {1st}, year = 2014, isbn = {978-3-95404-707-9}, }
Abstract: This dissertation examines concepts for wireless communication in large-scale, dense mesh networks, which can be used in future for plant control or building automation. It is shown that recent communication approaches for resource-constrained, IEEE 802.15.4 hardware do not scale well. This motivates the development of methodologies and protocols for reliable wireless communication in large-scale networks. This work covers the following topics: a "toolbox" for the development, programming, testing, and simulation of communication protocols for embedded systems; the decomposition of large networks into smaller subnets; concepts for scalable broadcasting and routing; the realization of selected network services such as emergency shutdowns and software updates.
Andreas Pfahl, Michael Randt, Carsten Holze and Stefan Unterschütz. Autonomous Light-Weight Heliostat with Rim Drives. Solar Energy, 92:230–240, June 2013.
[BibTeX]
@Article{Telematik_U_2013_HELIOMESH, author = {Andreas Pfahl and Michael Randt and Carsten Holze and Stefan Untersch{\"u}tz}, title = {Autonomous Light-Weight Heliostat with Rim Drives}, pages = {230-240}, journal = {Solar Energy}, volume = {92}, month = jun, year = 2013, }

The complete list of publications is available separately.

Supervised Theses

Completed Theses