Hamburg University of Technology

Displaying 1-19 of 19 results

  • White Papers // Jan 2013

    A Method for Access Authorisation Through Delegation Networks

    Owners of systems and resources usually want to control who can access them. This must be based on having a process for authorizing certain parties, combined with mechanisms for enforcing that only authorized parties are actually able to access those systems and resources. In distributed systems, the authorization process can...

    Provided By Hamburg University of Technology

  • White Papers // Apr 2012

    From Insider Threats to Business Processes That Are Secure-by-Design

    The authors argue that insider threat is a placeholder term that accompanies the transition from securing IT infrastructures to securing the socio-technical systems made possible by these IT infrastructures. The term insider in its literal interpretation loses meaning in a context where there are no stable perimeters one can refer...

    Provided By Hamburg University of Technology

  • White Papers // Jul 2011

    Methodologies for Comparing Clustering Algorithms in Wireless Sensor Networks

    This paper presents general methodologies for comparing distributed algorithms, which are exemplified by clustering algorithms in sensor networks. Significant metrics for evaluating the algorithms are introduced including aspects of a structural, analytical and simulative comparison. Finally a short, exemplary comparison of two clustering algorithms HEED and WCA is made. In...

    Provided By Hamburg University of Technology

  • White Papers // Jun 2011

    Design Considerations for a Universal Smart Energy Module for Energy Harvesting in Wireless Sensor Networks

    This paper presents the design of a universal energy module for nodes in wireless sensor networks. It supports a wide range of energy harvesters and energy storage systems. The focus is on the efficient conversion and storage of energy and to provide a smart platform for higher level energy management...

    Provided By Hamburg University of Technology

  • White Papers // Jun 2011

    Participatory Design of Web 2.0 Applications in SME Networks

    In increasingly complex and dynamic markets, Small and Medium-sized Enterprises (SME) face new challenges. Amongst others, these are innovativeness and technological expertise. In order to counteract the challenges, SMEs cooperate in corporate networks. Here, information and communication technologies are main drivers. At this point, Web 2.0 technologies are uttermost important....

    Provided By Hamburg University of Technology

  • White Papers // May 2011

    Construction of Connected Dominating Sets in Large-Scale MANETs Exploiting Self-Stabilization

    Available algorithms for the distributed construction of connected dominating sets in mobile ad hoc networks are inapplicable or suffer from a high complexity. This is mainly due to the resource-restricted nature of wireless devices, such as sensor nodes, and the error-prone character of the communication medium. This paper introduces and...

    Provided By Hamburg University of Technology

  • White Papers // May 2011

    Prediction Accuracy of Link-Quality Estimators

    The accuracy of Link-Quality Estimators (LQE) is mission-critical in many application scenarios in Wireless Sensor Networks (WSN), since the link-quality metric is used for routing decisions or neighborhood formation. Link-quality estimation must offer validity for different timescales. Existing LQEs describe and approximate the current quality in a single value only....

    Provided By Hamburg University of Technology

  • White Papers // Jan 2011

    A Low Complexity Transmitter Structure for OFDM-FDMA Uplink Systems

    The Orthogonal Frequency Division Multiplex (OFDM) transmission technique can efficiently deal with the effects of multi-path propagation in the broadband radio channel. It also has a high system inherent flexibility for designing a multiple access scheme by combining the conventional TDMA, FDMA and CDMA approaches with the OFDM modulation scheme....

    Provided By Hamburg University of Technology

  • White Papers // Jun 2010

    Performance of Energy-Efficient TDMA Schemes in Data-Gathering Scenarios With Periodic Sources

    Energy-efficient transportation of periodical sensor readings towards a single sink in wireless sensor networks is a challenging task. In general, two data-gathering strategies exist: on-demand and bulk data forwarding. For both strategies, cross-layer techniques are a promising approach, where TDMA is tailored to the underlying routing tree. Therefore, different TDMA...

    Provided By Hamburg University of Technology

  • White Papers // Jan 2010

    Survivability Analysis Under Non-Uniform Stochastically Dependent Node Damages

    In this paper, the authors analyze survivability of a wireless sensor network under a non-uniform damage model. The analysis assumes statistically dependent damages or node failures. Specifically, the damage process is represented by a non homogeneous Poisson-Boolean model. Network traffic surviving the damage process is analyzed using survivability measures like...

    Provided By Hamburg University of Technology

  • White Papers // Aug 2009

    Randomized Self-Stabilizing Algorithms for Wireless Sensor Networks

    Wireless Sensor Networks (WSNs) pose challenges not present in classical distributed systems: resource limitations, high failure rates, and ad hoc deployment. The lossy nature of wireless communication can lead to situations, where nodes lose synchrony and programs reach arbitrary states. Traditional approaches to fault tolerance like replication or global resets...

    Provided By Hamburg University of Technology

  • White Papers // Aug 2009

    Computing Bridges, Articulations, and 2-Connected Components in Wireless Sensor Networks

    This paper presents a simple distributed algorithm to determine the bridges, articulation points, and 2-connected components in asynchronous networks with an at least once message delivery semantics in time O(n) using at most 4m messages of length O(lg n). The algorithm does not assume a FIFO rule for message delivery....

    Provided By Hamburg University of Technology

  • White Papers // Aug 2009

    A Roadmap for Hardware and Software Support for Developing Energy-Efficient Sensor Networks

    Support for developing energy-efficient applications for wireless sensor networks is still scarce. In this paper a roadmap of a combined hardware and software approach is presented. The main idea is to collect state information and trace energy consumption of an application running in a testbed of real sensor nodes. Wireless...

    Provided By Hamburg University of Technology

  • White Papers // Aug 2009

    TinyMoBot: A Platform for Mobile Sensor Networks

    In many application scenarios of wireless sensor networks parts or the whole network consist of mobile sensor nodes. Currently, no common platform is available. This paper describes a project that has developed a mobile sensor node, based on standard components: a Crossbow IRIS mote and LEGO MINDSTORMS NXT components, i.e.,...

    Provided By Hamburg University of Technology

  • White Papers // Aug 2009

    Lifetime Prediction for Supercapacitor-Powered Wireless Sensor Nodes

    Energy-aware task scheduling is a novel research direction for wireless sensor networks. It depends on accurate models for lifetime prediction. In other terms, nodes must be aware of present and future energy resources. This paper addresses the first step towards reaching this goal: it explores discharging-characteristics of supercapacitors, discusses analytical...

    Provided By Hamburg University of Technology

  • White Papers // Aug 2009

    RFID for Mobile Applications

    The availability of fast anti-collision algorithms is crucial for most RFID applications. This paper aims to evaluate these algorithms for applications in which it is not intended to identify the entirety of moving objects but to detect as much tags as needed to allow orientation. The navigation of Automated Guided...

    Provided By Hamburg University of Technology

  • White Papers // Mar 2009

    Efficient Slot Assignment for the Many-to-One Routing Pattern in Sensor Networks

    In this paper an efficient TDMA slot assignment for the many-to-one routing pattern in wireless sensor networks is presented and analyzed. This assignment scheme is based on a simple to implement heuristic, named Spatial Path-based Reuse (SPR). By considering several metrics, the superiority of this heuristic with respect to energy...

    Provided By Hamburg University of Technology

  • White Papers // Feb 2009

    Cooperative Multiaccess for Wireless Metropolitan Area Networks: An Information-Centric Approach

    Multiaccess wireless networks have emerged as an active research field but, until now, previous work has mainly centered on integrating wireless LANs with cellular networks. With mobile WiMAX deployments increasing, many expect fierce competition between 3GPP and WiMAX Forum mobile broadband technologies. Authors take a different approach in this paper...

    Provided By Hamburg University of Technology

  • White Papers // Dec 2006

    The Early Phases of Innovation: Opportunities and Challenges of Public-Private Partnership

    Innovations have acquired a key-role in the growth and competition strategies of firms in today's globalized world. Governments in many, in developed as well as in developing, countries recognize the need to promote innovations and fund innovative projects; particularly those carried out in cooperation with other public sector institutions such...

    Provided By Hamburg University of Technology

  • White Papers // Jul 2011

    Methodologies for Comparing Clustering Algorithms in Wireless Sensor Networks

    This paper presents general methodologies for comparing distributed algorithms, which are exemplified by clustering algorithms in sensor networks. Significant metrics for evaluating the algorithms are introduced including aspects of a structural, analytical and simulative comparison. Finally a short, exemplary comparison of two clustering algorithms HEED and WCA is made. In...

    Provided By Hamburg University of Technology

  • White Papers // Mar 2009

    Efficient Slot Assignment for the Many-to-One Routing Pattern in Sensor Networks

    In this paper an efficient TDMA slot assignment for the many-to-one routing pattern in wireless sensor networks is presented and analyzed. This assignment scheme is based on a simple to implement heuristic, named Spatial Path-based Reuse (SPR). By considering several metrics, the superiority of this heuristic with respect to energy...

    Provided By Hamburg University of Technology

  • White Papers // Aug 2009

    Randomized Self-Stabilizing Algorithms for Wireless Sensor Networks

    Wireless Sensor Networks (WSNs) pose challenges not present in classical distributed systems: resource limitations, high failure rates, and ad hoc deployment. The lossy nature of wireless communication can lead to situations, where nodes lose synchrony and programs reach arbitrary states. Traditional approaches to fault tolerance like replication or global resets...

    Provided By Hamburg University of Technology

  • White Papers // Aug 2009

    Computing Bridges, Articulations, and 2-Connected Components in Wireless Sensor Networks

    This paper presents a simple distributed algorithm to determine the bridges, articulation points, and 2-connected components in asynchronous networks with an at least once message delivery semantics in time O(n) using at most 4m messages of length O(lg n). The algorithm does not assume a FIFO rule for message delivery....

    Provided By Hamburg University of Technology

  • White Papers // Aug 2009

    A Roadmap for Hardware and Software Support for Developing Energy-Efficient Sensor Networks

    Support for developing energy-efficient applications for wireless sensor networks is still scarce. In this paper a roadmap of a combined hardware and software approach is presented. The main idea is to collect state information and trace energy consumption of an application running in a testbed of real sensor nodes. Wireless...

    Provided By Hamburg University of Technology

  • White Papers // Aug 2009

    TinyMoBot: A Platform for Mobile Sensor Networks

    In many application scenarios of wireless sensor networks parts or the whole network consist of mobile sensor nodes. Currently, no common platform is available. This paper describes a project that has developed a mobile sensor node, based on standard components: a Crossbow IRIS mote and LEGO MINDSTORMS NXT components, i.e.,...

    Provided By Hamburg University of Technology

  • White Papers // Aug 2009

    Lifetime Prediction for Supercapacitor-Powered Wireless Sensor Nodes

    Energy-aware task scheduling is a novel research direction for wireless sensor networks. It depends on accurate models for lifetime prediction. In other terms, nodes must be aware of present and future energy resources. This paper addresses the first step towards reaching this goal: it explores discharging-characteristics of supercapacitors, discusses analytical...

    Provided By Hamburg University of Technology

  • White Papers // Jan 2010

    Survivability Analysis Under Non-Uniform Stochastically Dependent Node Damages

    In this paper, the authors analyze survivability of a wireless sensor network under a non-uniform damage model. The analysis assumes statistically dependent damages or node failures. Specifically, the damage process is represented by a non homogeneous Poisson-Boolean model. Network traffic surviving the damage process is analyzed using survivability measures like...

    Provided By Hamburg University of Technology

  • White Papers // Apr 2012

    From Insider Threats to Business Processes That Are Secure-by-Design

    The authors argue that insider threat is a placeholder term that accompanies the transition from securing IT infrastructures to securing the socio-technical systems made possible by these IT infrastructures. The term insider in its literal interpretation loses meaning in a context where there are no stable perimeters one can refer...

    Provided By Hamburg University of Technology

  • White Papers // Feb 2009

    Cooperative Multiaccess for Wireless Metropolitan Area Networks: An Information-Centric Approach

    Multiaccess wireless networks have emerged as an active research field but, until now, previous work has mainly centered on integrating wireless LANs with cellular networks. With mobile WiMAX deployments increasing, many expect fierce competition between 3GPP and WiMAX Forum mobile broadband technologies. Authors take a different approach in this paper...

    Provided By Hamburg University of Technology

  • White Papers // Jan 2011

    A Low Complexity Transmitter Structure for OFDM-FDMA Uplink Systems

    The Orthogonal Frequency Division Multiplex (OFDM) transmission technique can efficiently deal with the effects of multi-path propagation in the broadband radio channel. It also has a high system inherent flexibility for designing a multiple access scheme by combining the conventional TDMA, FDMA and CDMA approaches with the OFDM modulation scheme....

    Provided By Hamburg University of Technology

  • White Papers // Jun 2011

    Design Considerations for a Universal Smart Energy Module for Energy Harvesting in Wireless Sensor Networks

    This paper presents the design of a universal energy module for nodes in wireless sensor networks. It supports a wide range of energy harvesters and energy storage systems. The focus is on the efficient conversion and storage of energy and to provide a smart platform for higher level energy management...

    Provided By Hamburg University of Technology

  • White Papers // May 2011

    Construction of Connected Dominating Sets in Large-Scale MANETs Exploiting Self-Stabilization

    Available algorithms for the distributed construction of connected dominating sets in mobile ad hoc networks are inapplicable or suffer from a high complexity. This is mainly due to the resource-restricted nature of wireless devices, such as sensor nodes, and the error-prone character of the communication medium. This paper introduces and...

    Provided By Hamburg University of Technology

  • White Papers // May 2011

    Prediction Accuracy of Link-Quality Estimators

    The accuracy of Link-Quality Estimators (LQE) is mission-critical in many application scenarios in Wireless Sensor Networks (WSN), since the link-quality metric is used for routing decisions or neighborhood formation. Link-quality estimation must offer validity for different timescales. Existing LQEs describe and approximate the current quality in a single value only....

    Provided By Hamburg University of Technology

  • White Papers // Jun 2010

    Performance of Energy-Efficient TDMA Schemes in Data-Gathering Scenarios With Periodic Sources

    Energy-efficient transportation of periodical sensor readings towards a single sink in wireless sensor networks is a challenging task. In general, two data-gathering strategies exist: on-demand and bulk data forwarding. For both strategies, cross-layer techniques are a promising approach, where TDMA is tailored to the underlying routing tree. Therefore, different TDMA...

    Provided By Hamburg University of Technology

  • White Papers // Aug 2009

    RFID for Mobile Applications

    The availability of fast anti-collision algorithms is crucial for most RFID applications. This paper aims to evaluate these algorithms for applications in which it is not intended to identify the entirety of moving objects but to detect as much tags as needed to allow orientation. The navigation of Automated Guided...

    Provided By Hamburg University of Technology

  • White Papers // Dec 2006

    The Early Phases of Innovation: Opportunities and Challenges of Public-Private Partnership

    Innovations have acquired a key-role in the growth and competition strategies of firms in today's globalized world. Governments in many, in developed as well as in developing, countries recognize the need to promote innovations and fund innovative projects; particularly those carried out in cooperation with other public sector institutions such...

    Provided By Hamburg University of Technology

  • White Papers // Jan 2013

    A Method for Access Authorisation Through Delegation Networks

    Owners of systems and resources usually want to control who can access them. This must be based on having a process for authorizing certain parties, combined with mechanisms for enforcing that only authorized parties are actually able to access those systems and resources. In distributed systems, the authorization process can...

    Provided By Hamburg University of Technology

  • White Papers // Jun 2011

    Participatory Design of Web 2.0 Applications in SME Networks

    In increasingly complex and dynamic markets, Small and Medium-sized Enterprises (SME) face new challenges. Amongst others, these are innovativeness and technological expertise. In order to counteract the challenges, SMEs cooperate in corporate networks. Here, information and communication technologies are main drivers. At this point, Web 2.0 technologies are uttermost important....

    Provided By Hamburg University of Technology