Konrad Meier

Interfaces for timeline-based mobile video browsing

Browsing video on mobile devices such as smartphones and PDAs requires new interface designs and interaction concepts because of their small screen sizes. In this paper, we present four different interfaces which enable users to skim video at different replay speed levels: An interface supporting flicking similar to text browsing on an iPhone™, an elastic slider, and two variations which also allow for interactive speed manipulation. Based on a heuristic evaluation with all four designs, revised versions of the two most promising ones have been implemented. A comparative user study proved the usefulness of the proposed designs. Both interfaces showed the same performance (measured in time needed to solve typical browsing tasks) but achieved different results in subjective user assessments.

Assessing location privacy in mobile communication networks

In this paper we analyze a class of location disclosure in which location information from individuals is generated in an automated way, i.e. is observed by a ubiquitous infrastructure. Since such information is valuable for both scientific research and commercial use, location information might be passed on to third parties. Users are usually aware neither of the extent of the information disclosure (e.g. by carrying a mobile phone), nor how the collected data is used and by whom. In order to assess the expected privacy risk in terms of the possible extent of exposure, we propose an adversary model and a privacy metric that allow an evaluation of the possible privacy loss by using mobile communication infrastructure. Furthermore, a case study on the privacy effects of using GSM infrastructure was conducted with the goal of analyzing the side effects of using a mobile handset. Based on these results requirements for a privacy-aware mobile handheld device were derived.

Hierarchical reactive control for a team of humanoid soccer robots

Humanoid soccer serves as benchmark problem for artificial intelligence research and robotics. Every year, more teams are competing, e.g., in the RoboCup Humanoid league. As the robots manage the basic skills of walking, kicking, and getting up better, teams can focus on soccer skills and team coordination. The complexity of soccer behaviors and team play calls for structured behavior engineering.

Timeline-based video browsing on handheld devices

Small screen sizes and limited interaction possibilities appear to be the main challenges when developing video browsing interfaces for mobile devices, such as smartphones and PDAs. In this demo, we present several pen-based designs for interactive video browsing on a PDA. Each implementation enables users to skim a video along the timeline at different speeds and granularity levels. Using the whole touch-sensitive screen as input area, different pen movements are mapped to different browsing behaviors, offering more functionality and creating a better user experience.

Emulation-as-a-Service - The Past in the Cloud

Until now, emulation of legacy architectures has mostly been seen as a tool for hobbyists and as technical nostalgia. However, in a world in which research and development is producing almost entirely digital artifacts, new and efficient concepts for preservation and re-use are required. Furthermore, a significant amount of todays cultural work is purely digital. Hence, emulation technology appeals to a wider, non-technical, user-group since many of our digital objects cannot be re-used properly without a suitable runtime environment. This article presents a scalable and cost-effective Cloud-based Emulation-as-a-Service (EaaS) architecture, enabling a wide range of non-technical users to access emulation technology in order to re-enact their digital belongings. Together with a distributed storage and data management model we present an implementation from the domain of digital art to demonstrate the practicability of the proposed EaaS architecture.

Reclaiming Location Privacy in Mobile Telephony Networks—Effects and Consequences for Providers and Subscribers

Mobile telephony (e.g., Global System for Mobile Communications [GSM]) is todays most common communication solution. Due to the specific characteristics of mobile communication infrastructure, it can provide real added value to the user and various other parties. Location information and mobility patterns of subscribers contribute not only to emergency planning, general safety, and security, but are also a driving force for new commercial services. However, there is a lack of transparency in todays mobile telephony networks regarding location disclosure. Location information is generated, collected, and processed without being noticed by subscribers. Hence, by exploiting subscriber location information, an individuals privacy is threatened. We develop a utility-based opponent model to formalize the conflict between the additional utility of mobile telephony infrastructure being able to locate subscribers and the individuals privacy. Based on these results, measures were developed to improve an individuals location privacy through a user-controllable GSM software stack. To analyze and evaluate the effects of specific subscriber provider interaction, a dedicated test environment will be presented, using the example of GSM mobile telephony networks. The resulting testbed is based on real-life hardware and open-source software to create a realistic and defined environment that includes all aspects of the air interface in mobile telephony networks and thus, is capable of controlling subscriber–provider interaction in a defined and fully controlled environment.

Testbed for Mobile Telephony Networks

Mobile telephony and mobile communication are both crucial and critical infrastructures for todays society and contribute to its security and safety. In contrast to landline telephony with its physically protectable medium, mobile telephony utilizes air and electromagnetic waves as communication medium, which cannot be easily protected. Due to the specific design and the openly shared medium, mobile communication infrastructure is particularly vulnerable to threats linked to a wide range of security issues and failures caused by overload and blocking. Especially in critical situations like human stampede or natural disasters, the network could break down while remaining physically intact. That is contrary to the desired behavior in catastrophe scenarios, as the infrastructure is meant to provide emergency call functionality and communication for the rescue teams. While traditional usage scenarios even for major events are well researched, there is a lack of knowledge on how to make mobile telephony networks more resilient to unpredictable load in disaster events. We propose a test environment to analyze such scenarios using the example of GSM mobile telephony networks. Furthermore, we identify relevant network parameters and discuss their impact on network resilience. The resulting test bed is based on real hardware and open-source software in order to create a realistic and defined environment which includes all aspects of the air interface in mobile telephony networks and is capable of simulating an overload situation in a defined and fully controlled environment.

Dynamic provisioning of a HEP computing infrastructure on a shared hybrid HPC system

Experiments in high-energy physics (HEP) rely on elaborate hardware, software and computing systems to sustain the high data rates necessary to study rare physics processes. The Institut fr Experimentelle Kernphysik (EKP) at KIT is a member of the CMS and Belle II experiments, located at the LHC and the Super-KEKB accelerators, respectively. These detectors share the requirement, that enormous amounts of measurement data must be processed and analyzed and a comparable amount of simulated events is required to compare experimental results with theoretical predictions. Classical HEP computing centers are dedicated sites which support multiple experiments and have the required software pre-installed. Nowadays, funding agencies encourage research groups to participate in shared HPC cluster models, where scientist from different domains use the same hardware to increase synergies. This shared usage proves to be challenging for HEP groups, due to their specialized software setup which includes a custom OS (often Scientific Linux), libraries and applications. To overcome this hurdle, the EKP and data center team of the University of Freiburg have developed a system to enable the HEP use case on a shared HPC cluster. To achieve this, an OpenStack-based virtualization layer is installed on top of a bare-metal cluster. While other user groups can run their batch jobs via the Moab workload manager directly on bare-metal, HEP users can request virtual machines with a specialized machine image which contains a dedicated operating system and software stack. In contrast to similar installations, in this hybrid setup, no static partitioning of the cluster into a physical and virtualized segment is required. As a unique feature, the placement of the virtual machine on the cluster nodes is scheduled by Moab and the job lifetime is coupled to the lifetime of the virtual machine. This allows for a seamless integration with the jobs sent by other user groups and honors the fairshare policies of the cluster. The developed thin integration layer between OpenStack and Moab can be adapted to other batch servers and virtualization systems, making the concept also applicable for other cluster operators. This contribution will report on the concept and implementation of an OpenStack-virtualized cluster used for HEP workflows. While the full cluster will be installed in spring 2016, a test-bed setup with 800 cores has been used to study the overall system performance and dedicated HEP jobs were run in a virtualized environment over many weeks. Furthermore, the dynamic integration of the virtualized worker nodes, depending on the workload at the institutes computing system, will be described.

Location Privacy in Mobile Telephony Networks -- Conflict of Interest between Safety, Security and Privacy

Mobile telephony (e.g. GSM) is todays most common communication solution. Due to the specific characteristics of mobile communication infrastructure it can provide further real added value to different third parties. Using location information and mobility patterns, it not only contributes to emergency planning as well as safety and security, but also is a driving force behind new commercial services. However, by exploiting the subscribers location information and mobility patterns, an individuals privacy is threatened. We discuss this problem based on an opponent model and show how users may regain control over their mobile handset using a software GSM network stack. %While such behavior is rational for an individual subscriber and may not impair the technical functionality of the mobile infrastructure, the additional safety and security provided by the networks will decrease and/or be prevented.

Telefonie an Universitäten

Die letzte Dekade hat einen beschleunigten Wandel der Technologien in der Telefonie gesehen. Im gleichen Zuge haben sich die Kosten der Infrastrukturen und Gespräche erheblich verändert, was sich auch an den verschiedenen Landesverträgen für den Mobilfunkbereich ablesen lässt. Universitäten und Forschungseinrichtungen, die eigene Telefonanlagen betreiben, sollten sich daher bei anstehenden Migrationen auf VoIP und ihren zukünftigen Personalplanungen für die Telefonie von Überlegungen leiten lassen, wie ihre Kommunikationslandschaft in ein paar Jahren aussehen soll [1]. Mitarbeiter erwarten eine höhere Mobilität und Flexibilität. Für den Arbeitgeber sind sicherlich eine weitergehende Benutzerselbstadministration und die Einbindung in bestehende IdentityManagement-Strukturen interessant. Bei diesen Entwicklungen sollen Punkte wie Kostenentwicklungen oder Auswirkungen auf die Privatsphäre nicht außer Acht gelassen werden. Die Welt der Telefonkommunikation hat sich, angestoßen durch die rasante Verbreitung von Mobilfunknetzen, in den letzten zwei Dekaden erheblich verändert [2, 3]. Mit der zunehmenden Verbreitung des mobilen Internets kam mit den Smartphones eine neue Klasse sehr mächtiger Minicomputer auf, die das Kommunikationsverhalten heutiger Nutzer zusätzlich beeinflussen. Telefonie in der Universität oder in der Forschungseinrichtung bietet für viele Wissenschaftler/innen nur einen weiteren Kommunikationskanal und ist nicht mehr das einzige zur Verfügung stehende Mittel. Zur Fernkommunikation hat sich inzwischen eine größere Konkurrenz durch weiterer Dienste wie E-mail, Instant Messaging, Skype oder Soziale Netze etabliert. Viele Einrichtungen standen in den vergangenen Jahren und stehen in der Zukunft vor der Aufgabe, ihre Telefoninfrastrukturen grundlegend zu erneuern. Hierzu zählen die Ablösung alter Telefonanlagen zumeist nach dem Analogoder ISDN-Standard und das Rollout neuer VoIP-Infrastrukturen. Diese teilweise erheblichen Investitionen sollten von den Gedanken begleitet werden, was zukünftige Benutzer vom Medium Telefonie erwarten und wie sich diese Erwartungen in die Forschungsund Arbeitslandschaften der Zukunft nahtlos integrieren lässt. Eine denkbare Konsequenz könnte in der Reduktion der drahtgebundenen Inhouse-Telefonie auf ein gerätemäßig deutlich weniger umfangreiches Kerngeschäft liegen, welche den überwiegenden Teil der telefonischen Mitarbeiterkommunikation über Mobilgeräte unter Einbeziehung der Infrastrukturen Dritter, wie beispielsweise Mobilfunkprovider, abwickelt. Dieser Artikel beleuchtet hierzu eine Reihe von Überlegungen für zukünftige Entwicklungen aus der Perspektive verschiedener Bereiche, wie Installationsund laufende Kosten, Einbindung in bestehende Identity Management Infrastrukturen, Benutzerselbstadministration, Abrechnungsmodalitäten, allgemeine technologische Weiterentwicklung, Versorgungssicherheit sowie verschiedener Aspekte der Privatsphäre. Diese theoretischen Überlegungen wer-