- KonferenzbeitragTowards integration of user interaction and context event processing in intelligent living environments(ARCS 2012 Workshops, 2012) Lehmann, Simon; Schäfer, Jan; Dörner, Ralf; Schwanecke, Ulrich; Mühl, Gero; Richling, Jan; Herkersdorf, AndreasEvent processing plays a significant role in the current development of intelligent living environments. It ranges from processing of information produced by a magnitude of sensors to gain insight into the activities of the inhabitants on a more global scale, to the processing of immediate and rather short-lived events of user input on and around interactive systems embedded in common household furniture like tabletops or tablets. Based on the work conducted separately in those two fields, we found that the still evolving field of complex event processing (CEP) provides the methods and tools to handle those distinct use-cases equally. Especially the application to interactive systems, while being novel and uncommon, is well suited and further shows the broad applicability of CEP. The comparison of the two application fields shows that, even though the events occurring in them are distinguished by their intention, commonalities do exist and provide integration points. Furthermore, the integration of those applications within the context of smart homes allows to provide demand-oriented resource management, which realizes self adaptation and control.
- KonferenzbeitragA robust generation technique of common information based on characteristic of multipath fading channel by shaking handheld devices(ARCS 2012 Workshops, 2012) Iwamoto, Tomohiro; Tagashira, Shigeaki; Arakawa, Yutaka; Fukuda, Akira; Mühl, Gero; Richling, Jan; Herkersdorf, AndreasA rapid increase in handheld devices with wireless communication capabilities, such as cellular phones and smart phones, enables data communication in face-toface situations. The easy realization of secure data communication in such situations is necessary for ensuring safe and reliable networking environments as short-range wireless networks become more popular. One approach involving the generation of secret keys in each communication device using variations of the received signal strength indication (RSSI) values has been proposed in literature. However, it has a problem in that there are positions where eavesdroppers are able to obtain RSSI values that are highly correlated with those of legitimate devices. To address this problem, we propose a filtering technique that eliminates eavesdroppable parts from RSSI variations. Additionally, it is important to shake either one or both of two legitimate devices to change the propagation, considering that the elimination exploits the periodicity of the shake. Furthermore, we implemented a prototype system realizing the proposed method and evaluated its effectiveness. The results indicate that the proposed method can increase the robustness of common information, which is generated into the secret key without degrading its generation speed.
- KonferenzbeitragGoal-snapping: an empirical evaluation of object snapping in tangible and multi-touch interfaces(ARCS 2012 Workshops, 2012) Schmitt, Sebastian; Luderschmidt, Johannes; Haubner, Nadia; Lehmann, Simon; Dörner, Ralf; Schwanecke, Ulrich; Mühl, Gero; Richling, Jan; Herkersdorf, AndreasWe present “Goal-snapping”, a novel approach for applying snapping techniques to tangible and multi-touch interfaces. It can be used to support users in accomplishing basic tasks such as aligning, sorting or grouping of virtual objects. As using snapping on large surfaces poses challenges in interaction design, we identify and discuss according parameters in Goal-snapping. For sorting and aligning, we propose to use snappers that attract objects within a target zone and visually arrange them to present an overview. For exchanging objects among users, we propose that each user has a target snapper that acts as a goal to which objects can be flicked. A user study has shown that although participants embrace the use of snapping to automatically group objects in a sorting task, snapping does not accelerate the completion time and increases the error rate by accidently snapped objects. In a long distance positioning task, the use of snapping significantly increases task completion.
- KonferenzbeitragCellular location determination - reliability and trustworthiness of GSM location data(ARCS 2012 Workshops, 2012) Zahoransky, Richard M.; Rechert, Klaus; Meier, Konrad; Wehrle, Dennis; Suchodoletz, Dirk von; Mühl, Gero; Richling, Jan; Herkersdorf, AndreasWhile using mobile telephony networks, the serving network infrastructure is able to determine the mobile station's location. Until now, cellular telephony has been built on self-contained infrastructure, i.e. all network components have been certified and especially users have been unable to take over control over their mobile equipment's behavior. With the rising awareness on privacy issues, software-based mobile phone network stacks became available and thereby a new freedom degree for mobile subscribers is introduced. While slight modification to the mobile phones behavior will not impair with the general functionality of the network, cellular location determination becomes less reliable and trustworthy. We discuss user imposed measures to detect external location determination attempts and to obfuscate generated location information. With a dedicated testbed setup, the effects of location obfuscation were evaluated.
- KonferenzbeitragPhysiological Data in Future Livinig Environments(ARCS 2012 Workshops, 2012) Pfeiffer, Matthias; Stockhausen, Claudia; Reitz, Katharina; Krömker, Detlef; Mühl, Gero; Richling, Jan; Herkersdorf, AndreasIn this paper we develop three ideas for possible scenarios in future living environments. These ideas are based on technology which is present at the moment but may be deficient or not used in living environments. This paper focuses on showing possibilities, while knowing but neglecting actual practical problems. After introducing the potentials of physiological data, we present ideas for different scenarios. The first is concerned with games, trying to neglect the age differences of users and even up the difficulties in game-play. In the second scenario we show a concept for a supportive kitchen utilizing a brain computer interface and gesture detection. In the last scenario we present a draft for smart notification based on mental load. The ideas in this paper are not limited to elders or handicapped people, but most of them can be used to improve their lives.
- Editiertes BuchARCS 2012 Workshops(2012) Mühl, Gero; Richling, Jan; Herkersdorf, Andreas
- KonferenzbeitragFlexible scheduling and thread allocation for synchronous parallel tasks(ARCS 2012 Workshops, 2012) Kessler, Christoph W.; Hansson, Erik; Mühl, Gero; Richling, Jan; Herkersdorf, AndreasWe describe a task model and dynamic scheduling and resource allocation mechanism for synchronous parallel tasks to be executed on SPMD-programmed synchronous shared-memory MIMD parallel architectures with uniform, unit-time memory access and strict memory consistency, also known in the literature as PRAMs (Parallel Random Access Machines). Our task model provides a two-tier programming model for PRAMs that flexibly combines SPMD and fork-join parallelism within the same application. It offers flexibility by dynamic scheduling and late resource binding while preserving the PRAM execution properties within each task, the only limitation being that the maximum number of threads that can be assigned to a task is limited to what the underlying architecture provides. In particular, our approach opens for automatic performance tuning at run-time by controlling the thread allocation for tasks based on run-time predictions. By a prototype implementation of a synchronous parallel task API in the SPMD- based PRAM language Fork and experimental evaluation with example programs on the SBPRAM simulator, we show that a realization of the task model on a SPMD- programmable PRAM machine is feasible with moderate runtime overhead per task.
- KonferenzbeitragThe spectral relation between the cube-connected cycles and the shuffle-exchange network(ARCS 2012 Workshops, 2012) Riess, Christian; Strehl, Volker; Wanka, Rolf; Mühl, Gero; Richling, Jan; Herkersdorf, AndreasWe investigate the relation between the spectral sets (i. e., the sets of eigenvalues, disregarding multiplicities) of two d-dimensional networks popular in parallel computing: the Cube-Connected Cycles network CCC(d) and the Shuffle-Exchange network SE(d). We completely characterize their spectral sets. Additionally, it turns out that for any odd d, the SE(d)-eigenvalues set is precisely the same as the CCC(d)- eigenvalues set. For any even d, however, the SE(d)-eigenvalues form a proper subset of the set of CCC(d)-eigenvalues.
- KonferenzbeitragI/O-efficient approximation of graph diameters by parallel cluster growing – a first experimental study(ARCS 2012 Workshops, 2012) Ajwani, Deepak; Beckmann, Andreas; Meyer, Ulrich; Veith, David; Mühl, Gero; Richling, Jan; Herkersdorf, AndreasA fundamental step in the analysis of a massive graph is to compute its diameter. In the RAM model, the diameter of a connected undirected unweighted graph can be efficiently 2-approximated using a Breadth-First Search (BFS) traversal from an arbitrary node. However, if the graph is stored on disk, even an external memory BFS traversal is prohibitive, owing to the large number of I/Os it incurs. Meyer [Mey08] proposed a parametrized algorithm to compute an approximation of graph diameter with fewer I/Os than that required for exact BFS traversal of the graph. The approach is based on growing clusters around randomly chosen vertices `in parallel' until their fringes meet. We present an implementation of this algorithm and compare it with some simple heuristics and external-memory BFS in order to determine the trade-off between the approximation ratio and running-time achievable in practice. Our experiments show that with carefully chosen parameters, the new approach is indeed capable to produce surprisingly good diameter approximations in shorter time. We also confirm experimentally, that there are graph-classes where the parametrized approach runs into bad approximation ratios just as the theoretical analysis in [Mey08] suggests.
- KonferenzbeitragAchieving scalability for job centric monitoring in a distributed infrastructure(ARCS 2012 Workshops, 2012) Hilbrich, Marcus; Müller-Pfefferkorn, Ralph; Mühl, Gero; Richling, Jan; Herkersdorf, AndreasJob centric monitoring allows to observe jobs on remote computing resources. It may offer visualisation of recorded monitoring data and helps to find faulty or misbehaving jobs. If installations like grids or clouds are observed monitoring data of many thousands of jobs have to be handled. The challenge of job centric monitoring infrastructures is to store, search and access data collected in huge installations like grids or clouds. We take this challenge with a distributed layer based architecture which provides a uniform view to all monitoring data. The concept of this infrastructure called SLAte and an analysis of the scalability is provided in this paper.