Fraunhofer-Institut für Angewandte Informationstechnik FIT

Filters

46
1
Reset filters

Settings
Now showing 1 - 10 of 46
No Thumbnail Available
Publication

TrustMUSE: A model-driven approach for trust management

2014 , Vinkovits, M. , Reiners, R. , Zimmermann, A.

With the increasing acceptance of Trust Management as a building block of distributed applications, the issue of providing its benefits to real world applications becomes more and more relevant. There are multiple Trust Management frameworks ready to be applied; however, they are either unknown to developers or cannot sufficiently be adapted to applications use cases. In our research, we have defined a meta model to modularize Trust Management, where each element in the model has clearly defined dependencies and responsibilities also enforced by a complete API. Based on this model, we were able to develop a process supported by a number of tools that enables non-security expert users to find an applicable Trust Management solution for their specific problem case. Our solution collectively called the TrustMUSE system has evolved over an iterative user-centered development process: starting with multiple focus group workshops to identify requirements, and having multip le prototypes to conduct usage observations. Our user evaluation has shown that our system is understandable for system designers, and is able to support them in their work.

View
No Thumbnail Available
Publication

Reconstructing normality. The use of infrastructure leftovers in crisis situations as inspiration for the design of resilient technology

2013 , Al-Akkad, A. , Ramirez, L. , Denef, S. , Boden, A. , Wood, L. , Büscher, M. , Zimmermann, A.

In this paper, we examine challenges people face in situations of disrupted network infrastructures and how people use surviving portions of technology to cope with these challenges. We show how an important aspect in crises is the disturbance of services caused by disruptions in underlying technological structures. In such situations, people resort to all possible means to "reconstruct normality" in the sense of restoring their ability to communicate. For doing so, people often make creative use of the remains of the technological landscape. Building on the analysis of interviews with crises witnesses and first responders, external reports and scientific literature, we propose and describe three categories of mechanisms involving the creative use of surviving technology in crisis situations. We argue that studying these mechanisms can provide a key source of inspiration to define qualities of resilient architectures, and use these mechanisms as creative input to propose architectural qualities that can potentially make communication systems more resilient in the face of crises.

View
No Thumbnail Available
Publication

User study: Involving civilians by smart phones during emergency situations

2011 , Al-Akkad, A. , Zimmermann, A.

This paper concerns a preliminary user study to determine the acceptance of a mobile application that is supposed to involve civilians during emergencies. In particular, the focus is on bystanders. Their intervention during emergencies constitutes a delicate issue, since they were traditionally considered as a rather annoying party being merely observers of incidents. However, with the ubiquity and ever-increasing capabilities of cell phones there might emerge a great potential to flip the coin and to benefit from bystanders playing from now on a contributive role. To examine this hypothesis, we conducted semi-structured interviews with 24 persons. The result of our study shows that people are willing to use such mobile assisting system, and thus we take it as a positive starting signal to continue our research into this direction considering the elicited user constraints.

View
No Thumbnail Available
Publication

Middleware for building pervasive systems

2009 , Al-Akkad, A. , Pramudianto, F. , Jahn, M. , Zimmermann, A.

Pervasive software succeeds when it is leveraged permeable into the background of everyday life and work supporting users more properly to fulfill their tasks than they used to do it with pre-existing techniques. Hence, we hypothesize, that a particular pervasive system may comprise certain styles of intelligent networking embedded systems, secure communication patterns, context-aware assisting, novel techniques of interaction and many more sophisticated features. Building such highly flexible systems poses diverse challenges for an underlying middleware platform. This paper reports - from a developers' point of view - on experiences we gained from using a generic middleware framework that targets the rapid development of pervasive systems. Based on two case studies, conducted in the healthcare and home automation domain, we describe in detail how we designed and deployed two prototypical ubiquitous applications. We elaborate the difficulties our designated middleware framework helped to us to overcome, and at th e same time look on the intrinsic complexity networked embedded systems constitute. Finally, we conclude with a set of lessons learned for designing pervasive systems and sketch ideas for future work.

View
No Thumbnail Available
Publication

Tweeting 'when online is off'? Opportunistically creating mobile ad-hoc networks in response to disrupted infrastructure

2014 , Al-Akkad, A. , Raffelsberger, C. , Boden, A. , Ramirez, L. , Zimmermann, A.

In this paper, we present a system that enables people to post and receive tweets despite disruptions of existing network infrastructure. Our system opportunistically deploys mobile ad hoc networks (MANETs) based on Wi-Fi in which people can communicate with each other in a peer-to-peer fashion. A MANET per se constitutes an isolated island, but as people carry devices around that can join other MANETs, eventually people can transport previously collected data to the online world. Compared to other systems that aim to enable communication in crisis, our system differs in two ways: it does not rely on existing network infrastructure, and it exploits established protocols and standards allowing it to run on off-the-shelf, commercially available smartphones. We evaluated our prototype with a group of students and practitioners. Overall, we received positive feedback on the potential of our technology, but also were pointed to limitations requiring future work.

View
No Thumbnail Available
Publication

Defining a trust framework design process

2013 , Vinkovits, M. , Zimmermann, A.

Trust Management researchers have created several sound frameworks for well-defined problems based on their deep understanding of the field and the current state of the art. However, Trust Management experts are rarely contacted for the design of distributed business applications. Developers of these kinds of business applications are not familiar with latest results and are only aware of a very limited set of applicable solutions. This hinders the adaption of these novel security solutions into provided future services. To support the integration of Trust Management into these areas we defined a design process, which can be applied systematically by developers. Based on the design process they can use their scenario knowledge to narrow down their design space and finally select from a limited set of applicable implementations the best fit. We extended the static TrustFraMM meta-description of Trust Management in a way to enable it to support the exploration and exclusion of existing trust functionality implementations. We built our process on a number of requirements collected through our user-centered design approach. We also provide a possible visualization of the process which we evaluated using a paper prototype. Our process had a positive user acceptance among the questioned users.

View
No Thumbnail Available
Publication

Utilizing cell phones for bystander intervention during emergencies

2011 , Al-Akkad, A. , Reiners, R. , Zimmermann, A.

Due to the ubiquity and ever-increasing capabilities of cell phones, they have been exploited for mobile data collection in diverse domains [1]. In this position paper, we hypothesize that bystanders can contribute to the handling of emergencies by means of usage of smart phones. To examine our hypothesis, we conducted at first 24 interviews, as described in [2]. Time staggered we also interviewed two persons who experienced the crisis at a stampede [3] at the Love Parade music festival in Germany in the year of 2010. Based on the results of both studies, we draw conclusions for the design of a potential mobile emergency app being dedicated for bystanders.

View
No Thumbnail Available
Publication

Help beacons: Design and evaluation of an ad-hoc lightweight S.O.S. system for smartphones

2014 , Al-Akkad, A. , Ramirez, L. , Boden, A. , Randall, D. , Zimmermann, A.

We present the design and evaluation of a lightweight mobile S.O.S. system that facilitates ad-hoc communication between first responders and victims in emergency situations. Our approach leverages established protocols and standards in unforeseen ways to provide a platform supporting the creation of short-lived communication links. The system comprises two mobile applications: One victim application that allows the broadcasting of distress signals by a novel use of Wi-Fi SSIDs; and a responder application that allows first responders to discover and trace the people broadcasting the signals. The main difference of our system with other platforms enabling communication in crisis situations is that our system is independent from existing network infrastructure and runs on off-the-shelf, commercially available smartphones. We describe the results of our evaluation process in the context of both a design evaluation during a real world emergency response exercise and of two user workshops in preparation for an upcoming large-scale exercise.

View
No Thumbnail Available
Publication

Context adaptive systems

2011 , Oppermann, R. , Zimmermann, A.

View
No Thumbnail Available
Publication

Incentives for maintaining high-quality source code

2010 , Prause, C. , Reiners, R. , Dencheva, S. , Zimmermann, A.

Source code is a medium of communication between human developers. Understandability is the key to maintainable and reusable code. Yet code developed collaboratively with weak ownership is a common property resource that su ers from di usion of responsibility, and hence gradual deterioration. Such misbehavior is usually dealt with with strict usage regulations, e.g. coding rules enforced by reviews. Instead, we take for granted a way to privatize code - e.g. based on authorship information obtained from Subversion - and discuss di fferent ways to reward well-mannered coding, while focussing on friendly self-organization and low coercive power in scienti c environments.

View