Florian Fuchs

Distributed Negotiation-Based Task Planning for a Flexible Manufacturing Environment

In a flexible manufacturing environment a group of autonomous agents such as autonomous mobile robots and intelligent manufacturing units is supposed to cooperate and avoid bad interaction. Thus they must have the capability to build a common multi-agent plan through detailed adequate agreements and take into consideration the group goals as well as those of the individual agents.

Adaptive and fault-tolerant service composition in peer-to-peer systems

Service-orientation enables dynamic interoperation of distributed services and facilitates seamless service provision or runtime creation of new applications. This dynamic service composition is particularly powerful in peer-to-peer (P2P) systems which offer scalability through self-management and autonomy. However, P2P service composition is nontrivial due to permanent peer churn and lack of central control. Existing approaches reduce composite service initialization to an NP-hard path finding problem. Thus, peer failure adaptation is costly and runtime consideration of peer logons or load changes is not practicable. This paper introduces logical peer groups for service composition. They enable runtime composite service reconfiguration including the migration of services to other peers. A prototype implementation is presented and the algorithms are evaluated through both formal and empirical analysis. The evaluation shows that the approach results in significant reduction of computational complexity, improves fault-tolerance and enables adaptation of logons and load changes which has not been possible so far.

Context-aware personalization for mobile multimedia services

With the increasing amount of digital multimedia content, the user is more and more overstrained. A promising solution for this problem is personalization that assists the user in selecting content with respect to the users interest. Since the capabilities of mobile devices increased significantly in the recent years, the number of mobile multimedia services grows steadily. The mobile services are confronted with a much more changing environment than stationary services. This additional information enables even more precise personalization. This paper introduces an approach for context-aware personalization of mobile multimedia services. We developed a generic framework for application developers that can easily be configured and extended with application-specific algorithms matching content and context. In the proposed system, content selection is performed in a distributed way.

Implicit Authorization for Social Location Disclosure

Being increasingly equipped with highly-accurate positioning technologies, today’s mobile phones enable their owners to transmit their current position over the cellular network and share it with others. So-called location-based community services make use of this possibility, for example for locating friends, co-workers or family members. Of course, these services give target persons control about the way location data may be accessed by others. So far, this is done by the target explicitly granting or denying permissions through authorization policies or ad-hoc authorization. Unfortunately, apart from bringing along high management effort, the concept of explicit authorization in such a privacy-sensitive application entails the disadvantage of social difficulties. In this paper we introduce the concept of implicit authorization, which has reciprocity as its central element: Another person is granted access to a certain target’s location information implicitly by the target accessing the information of that other person as well. The technique aims to reduce social pressure on the target person when deciding whether a certain person may locate her or not. Also, the target person is relieved from management overhead. Several realizations of implicit authorization are proposed. They differ in the service pattern (reactive/proactive) they are useful for and the way a once given access grant is revoked.

Implicit Authorization for Accessing Location Data in a Social Context

Being increasingly equipped with highly-accurate positioning technologies, todays mobile phones enable their owners to transmit their current position over the cellular network and share it with others. So-called location-based community services make use of this possibility, for example for locating friends or family members. Such services give target persons control about the way location data may be accessed by others. So far, this is done by the target explicitly granting or denying permissions through authorization policies or ad-hoc authorization. Unfortunately, apart from bringing along high management effort, the concept of explicit authorization in such a privacy-sensitive application entails the disadvantage of social difficulties. In this paper we introduce the concept of implicit authorization, where an inquirer is granted access to the required information as the result of a certain activity of the target that is not solely dedicated to managing its own location information. In the proposed realization of implicit authorization, access to ones own information is granted implicitly by accessing the information of another person. The approach is analyzed theoretically and computationally. It turns out that management overhead is minimized while guaranteeing better social acceptability

Supporting proactive Location-Aware services in cellular networks

Location-aware services (LAS) adapt content and service execution to the user’s current physical location. In today’s cellular networks, only reactive LASs are offered. The user has to explicitly request the service before the network determines her current location and starts service execution. However, in the future the user would like to see proactive LASs, which are automatically triggered as soon as she enters a pre-defined point of interest. In contrast to reactive LASs, this requires that the network performs a continuous user tracking, which entails expensive point-to-point signaling at the air interface.

Towards Entity-Centric Wide-Area Context Discovery

Mobile computing leads to different usage situations for the same service due to the mobility of the user. Context aware services (CASs) try to exploit information about the current usage situation in order to better satisfy the users needs. Especially on a large-scale, CASs face the problem of discovering appropriate context information services (CISs), which are capable of delivering a particular type of context information about a particular entity. The mapping between CISs and entities, however, is highly dynamic, especially when entities are mobile and CISs have only limited coverage areas. New mechanisms are needed for organizing CISs and their currently covered entities in a scalable, robust and decentralized way so that they can be discovered by (potentially mobile) CASs when required. As a possible solution we present the design of an entity-centric wide- area context discovery service based on distributed hashtables. It requires no dedicated infrastructure, and ontologies are used for achieving interoperability. The concept is evaluated by a prototype based on the OpenDHT infrastructure. Experimental results demonstrate the feasibility and performance of the approach.

Optimizing Position Updates for kNN - Is It Worth It?

Keeping a mobile device always up-do-date about the k nearest neighbor (kNN) points of interest (PoIs) is a common challenge of location based services. The challenge lies in the fact that the set of PoIs available at the device needs to always remain correct and fresh while the mobile user may be constantly moving about. To this end, in a very simple approach, the position of the device could be continuously updated with the server- side, whenever it changes. Since this simple approach creates a potential communication overhead, several optimizations have been proposed in literature, all of which significantly reduce the amount of messages sent over the air. However, location based service (LBS) developers have been left clueless until today about whether deploying those complex strategies into their systems actually improves battery life sig- nificantly - which is arguably the most important aspect for the end user. As a way to remedy, this paper critically examines optimized kNN tracking, based on real-life data sets and in the light of actual battery drainage.

Smart Monitoring for Physical Infrastructures

Infrastructures are the backbone of today’s economies. Physical Infrastructures such as transport and energy networks are vital for ensuring the functioning of a society. They are strained by the ever increasing demand for capacity, the need for stronger integration with other infrastructures, and the relentless push for higher cost efficiency.

From Personal Assistance to Industrial Solutions – A Generic Ambient Intelligence Architecture and Framework (Von persönlicher Assistenz zu industriellen Lösungen – eine generische Architektur und ein generisches Framework für Ambient Intelligence)

Summary Ambient Intelligence refers to the vision of computationally-enriched environments that are sensitive and responsive to the presence, intention and activity of people. We extend this vision from personal to the business and industrial domain and describe a technological framework that can be leveraged in both worlds. Zusammenfassung Ambient Intelligence repräsentiert die Vision von elektronisch angereicherten Umgebungen, die sensitiv auf die Präsenz, Absichten und Aktivitäten von Personen reagieren. Wir erweitern diese Vision von der privaten in die geschäftliche und industrielle Domäne und beschreiben ein Technologie-Framework, das in beiden Domänen eingesetzt werden kann.