Torsten Braun - Academia.edu (original) (raw)
Papers by Torsten Braun
A mobile ad-hoc network is a collection of wireless terminals that can be deployed rapidly and is... more A mobile ad-hoc network is a collection of wireless terminals that can be deployed rapidly and is self-organising. Integrating ad-hoc networks with a well-established cellular network can improve communication and security, as well as enrich the cellular services. How can secure data communications based on temporarily acquired broadband access between two users not knowing each other be achieved?
Computer Communications, 2006
Application Level Multicast is a promising approach to overcome the deployment problems of IP lev... more Application Level Multicast is a promising approach to overcome the deployment problems of IP level multicast. In this paper, we propose an algorithm to compute a set of n-1 backup multicast delivery trees from the default multicast tree. Each backup multicast tree is characterized by the fact that exactly one link of the default multicast tree is replaced by a backup link from the set of available links. The trees can be calculated individually by each of the nodes. The so-called backup multicast tree algorithm can calculate this set of trees with a complexity of O (m log n). This is identical to the complexity of well known minimum spanning tree algorithms. The backup multicast tree algorithm is the basis for the reduced multicast tree algorithm that can calculate a tree, which results from the default multicast tree by removing a particular node and by replacing the links of the removed node. We show mechanisms that can be used to choose these explicit backup trees.
Lecture Notes in Computer Science, 2005
We propose the so-called backup tree algorithm to compute a set of n-1 backup multicast delivery ... more We propose the so-called backup tree algorithm to compute a set of n-1 backup multicast delivery trees from the default multicast tree for application level multicast. For each backup multicast tree exactly one link of the default multicast tree is replaced by a backup link from the set of available links. The backup tree algorithm calculates the n-1 trees with a complexity of O (m log n).
XTP and VMTP on Multiprocessor Architectures
The processing of data units inside a communication node became to be the bottleneck in communica... more The processing of data units inside a communication node became to be the bottleneck in communications, because pro- tocol processing did not increase in the same order of magni- tude as the networks' bandwidth. For that reason, new and efficient approaches to surmount this bottleneck have been proposed. First, the development of new protocols and, second, the use of dedicated hardware platforms have a number of advantages. Throughout this paper the integration of these advantages will be presented using the light-weight protocols XTP (1) and VMTP (2) on multiprocesso r architectures. Measurement and simulation results proof the performance gain of the selected approach. The results show that XTP and VMTP are more appropriate for implementations on parallel architectures than comparable OSI protocols.
Lecture Notes in Computer Science, 1999
The objectives of the CATI project (Charging and Accounting Technology for the Internet) include ... more The objectives of the CATI project (Charging and Accounting Technology for the Internet) include the design, implementation, and evaluation of charging and accounting mechanisms for Internet services and Virtual Private Networks (VPN). They include the enabling technology support for open, Internet-based Electronic Commerce platforms in terms of usage-based transport service charging as well as high-quality Internet transport services and its advanced and flexible configurations for VPNs. In addition, security-relevant and trust-related issues in charging, accounting, and billing processes are investigated. Important application scenarios, such as an Internet telephony application as well as an Electronic Commerce shopping network, demonstrate the applicability and efficiency of the developed approaches. This work is complemented by an appropriate cost model for Internet communication services, including investigations of suitable usage-sensitive pricing models.
Computer Communications - COMCOM, 2006
Application Level Multicast is a promising approach to overcome the deployment problems of IP lev... more Application Level Multicast is a promising approach to overcome the deployment problems of IP level multicast by establishing deliv- ery trees using overlay links among end systems. This paper presents algorithms to support traffic engineering, to improve the reliability of multicast delivery, and to facilitate secure group communications. First, we introduce the so-called backup multicast tree algorithm to compute a set of n � 1 backup multicast delivery trees from the default multicast tree. Each backup multicast tree has exactly one link of the default multicast tree that is replaced by a backup link from the set of available links. The algorithm can calculate this set of trees with a complexity of O (m log n), which is identical with the complexity of well known minimum spanning tree algorithms. The so-called reduced multicast tree algorithm is based on the backup multicast tree algorithm and can calculate a tree from the default multicast tree by removing a particular node and ...
Evaluating the trade-off between energy efficiency and QoE in wireless mesh networks
2012 4th International Conference on Communications and Electronics, ICCE 2012, 2012
ABSTRACT The increasing usage of wireless networks creates new challenges for wireless access pro... more ABSTRACT The increasing usage of wireless networks creates new challenges for wireless access providers. On the one hand, providers want to satisfy the user demands but on the other hand, they try to reduce the operational costs by decreasing the energy consumption. In this paper, we evaluate the trade-off between energy efficiency and quality of experience for a wireless mesh testbed. The results show that by intelligent service control, resources can be better utilized and energy can be saved by reducing the number of active network components. However, care has to be taken because the channel bandwidth varies in wireless networks. In the second part of the paper, we analyze the trade-off between energy efficiency and quality of experience at the end user. The results reveal that a provider's service control measures do not only reduce the operational costs of the network but also bring a second benefit: they help maximize the battery lifetime of the end-user device.
Service-Centric Networking
2011 IEEE International Conference on Communications Workshops (ICC), 2011
Content-centric networking is a novel paradigm for the Future Internet. This paper argues that co... more Content-centric networking is a novel paradigm for the Future Internet. This paper argues that content-centric net- working should be generalized towards a service-centric net- working scheme. We propose a service-centric networking design based on an object-oriented approach, in which content and ser- vices are considered objects. We show implementation architec- tures for example services and how these can benefit from
INVESTIGATION ON THE EVOLUTION OF AN INDOOR ROBOTIC LOCALIZATION SYSTEM BASED ON WIRELESS NETWORKS
Applied Artificial Intelligence, 2013
ABSTRACT This work addresses the evolution of an artificial neural network ANN to assist in the p... more ABSTRACT This work addresses the evolution of an artificial neural network ANN to assist in the problem of indoor robotic localization. We investigate the design and building of an autonomous localization system based on information gathered from wireless networks WN. The article focuses on the evolved ANN, which provides the position of a robot in a space, as in a Cartesian coordinate system, corroborating with the evolutionary robotic research area and showing its practical viability. The proposed system was tested in several experiments, evaluating not only the impact of different evolutionary computation parameters but also the role of the transfer functions on the evolution of the ANN. Results show that slight variations in the parameters lead to significant differences on the evolution process and, therefore, in the accuracy of the robot position.
Journal of Systems Architecture, 2014
ABSTRACT Abstract The application of pesticides and fertilizers in agricultural areas is of cruci... more ABSTRACT Abstract The application of pesticides and fertilizers in agricultural areas is of crucial importance for crop yields. The use of aircrafts is becoming increasingly common in carrying out this task mainly because of their speed and effectiveness in the spraying operation. However, some factors may reduce the yield, or even cause damage (e.g. crop areas not covered in the spraying process, overlapping spraying of crop areas, applying pesticides on the outer edge of the crop). Weather conditions, such as the intensity and direction of the wind while spraying, add further complexity to the problem of maintaining control. In this paper, we describe an architecture to address the problem of self-adjustment of the UAV routes when spraying chemicals in a crop field. We propose and evaluate an algorithm to adjust the UAV route to changes in wind intensity and direction. The algorithm to adapt the path runs in the UAV and its input is the feedback obtained from the wireless sensor network (WSN) deployed in the crop field. Moreover, we evaluate the impact of the number of communication messages between the UAV and the WSN. The results show that the use of the feedback information from the sensors to make adjustments to the routes could significantly reduce the waste of pesticides and fertilizers.
In this paper, the EuQoS Consortium offers its first architecture release in order to provide an ... more In this paper, the EuQoS Consortium offers its first architecture release in order to provide an initial view on how end to end QoS is provided over multiple and heterogeneous networks. The EuQoS end to end Architecture has two views; a network deployment view across a number of autonomous systems (AS) domains and a software view within an AS.
The provision of guaranteed Quality of Service (QoS) in the Internet requires appropriate system ... more The provision of guaranteed Quality of Service (QoS) in the Internet requires appropriate system support for both resource allocation and charging. Differentiated Services is an approach for the former which targets a high level of scal- ability. The inclusion of flow-based charging characteristics, such as QoS, extent of service usage and traffic destination dependencies, into Differentiated Service models requires specific
Wireless Sensor Network by Torsten Braun
Communications of the ACM, 2012
wIR eLess senso R n eT woR Ks (WSNs) play a key role in the emerging "real-world Internet," with ... more wIR eLess senso R n eT woR Ks (WSNs) play a key role in the emerging "real-world Internet," with several large-scale WSNs being deployed; see, for example, Bernat 2 and Dudek et al. However, WSN development is inherently complex, involving hardware design, embedded and distributed programming, heterogeneity, scale, and unpredictable environmental changes. Addressing this complexity, testbed-based experimentation (recommended by Weiser 32 ) is increasingly the norm for developing and optimizing WSN systems in a controllable environment prior to deployment.
A mobile ad-hoc network is a collection of wireless terminals that can be deployed rapidly and is... more A mobile ad-hoc network is a collection of wireless terminals that can be deployed rapidly and is self-organising. Integrating ad-hoc networks with a well-established cellular network can improve communication and security, as well as enrich the cellular services. How can secure data communications based on temporarily acquired broadband access between two users not knowing each other be achieved?
Computer Communications, 2006
Application Level Multicast is a promising approach to overcome the deployment problems of IP lev... more Application Level Multicast is a promising approach to overcome the deployment problems of IP level multicast. In this paper, we propose an algorithm to compute a set of n-1 backup multicast delivery trees from the default multicast tree. Each backup multicast tree is characterized by the fact that exactly one link of the default multicast tree is replaced by a backup link from the set of available links. The trees can be calculated individually by each of the nodes. The so-called backup multicast tree algorithm can calculate this set of trees with a complexity of O (m log n). This is identical to the complexity of well known minimum spanning tree algorithms. The backup multicast tree algorithm is the basis for the reduced multicast tree algorithm that can calculate a tree, which results from the default multicast tree by removing a particular node and by replacing the links of the removed node. We show mechanisms that can be used to choose these explicit backup trees.
Lecture Notes in Computer Science, 2005
We propose the so-called backup tree algorithm to compute a set of n-1 backup multicast delivery ... more We propose the so-called backup tree algorithm to compute a set of n-1 backup multicast delivery trees from the default multicast tree for application level multicast. For each backup multicast tree exactly one link of the default multicast tree is replaced by a backup link from the set of available links. The backup tree algorithm calculates the n-1 trees with a complexity of O (m log n).
XTP and VMTP on Multiprocessor Architectures
The processing of data units inside a communication node became to be the bottleneck in communica... more The processing of data units inside a communication node became to be the bottleneck in communications, because pro- tocol processing did not increase in the same order of magni- tude as the networks' bandwidth. For that reason, new and efficient approaches to surmount this bottleneck have been proposed. First, the development of new protocols and, second, the use of dedicated hardware platforms have a number of advantages. Throughout this paper the integration of these advantages will be presented using the light-weight protocols XTP (1) and VMTP (2) on multiprocesso r architectures. Measurement and simulation results proof the performance gain of the selected approach. The results show that XTP and VMTP are more appropriate for implementations on parallel architectures than comparable OSI protocols.
Lecture Notes in Computer Science, 1999
The objectives of the CATI project (Charging and Accounting Technology for the Internet) include ... more The objectives of the CATI project (Charging and Accounting Technology for the Internet) include the design, implementation, and evaluation of charging and accounting mechanisms for Internet services and Virtual Private Networks (VPN). They include the enabling technology support for open, Internet-based Electronic Commerce platforms in terms of usage-based transport service charging as well as high-quality Internet transport services and its advanced and flexible configurations for VPNs. In addition, security-relevant and trust-related issues in charging, accounting, and billing processes are investigated. Important application scenarios, such as an Internet telephony application as well as an Electronic Commerce shopping network, demonstrate the applicability and efficiency of the developed approaches. This work is complemented by an appropriate cost model for Internet communication services, including investigations of suitable usage-sensitive pricing models.
Computer Communications - COMCOM, 2006
Application Level Multicast is a promising approach to overcome the deployment problems of IP lev... more Application Level Multicast is a promising approach to overcome the deployment problems of IP level multicast by establishing deliv- ery trees using overlay links among end systems. This paper presents algorithms to support traffic engineering, to improve the reliability of multicast delivery, and to facilitate secure group communications. First, we introduce the so-called backup multicast tree algorithm to compute a set of n � 1 backup multicast delivery trees from the default multicast tree. Each backup multicast tree has exactly one link of the default multicast tree that is replaced by a backup link from the set of available links. The algorithm can calculate this set of trees with a complexity of O (m log n), which is identical with the complexity of well known minimum spanning tree algorithms. The so-called reduced multicast tree algorithm is based on the backup multicast tree algorithm and can calculate a tree from the default multicast tree by removing a particular node and ...
Evaluating the trade-off between energy efficiency and QoE in wireless mesh networks
2012 4th International Conference on Communications and Electronics, ICCE 2012, 2012
ABSTRACT The increasing usage of wireless networks creates new challenges for wireless access pro... more ABSTRACT The increasing usage of wireless networks creates new challenges for wireless access providers. On the one hand, providers want to satisfy the user demands but on the other hand, they try to reduce the operational costs by decreasing the energy consumption. In this paper, we evaluate the trade-off between energy efficiency and quality of experience for a wireless mesh testbed. The results show that by intelligent service control, resources can be better utilized and energy can be saved by reducing the number of active network components. However, care has to be taken because the channel bandwidth varies in wireless networks. In the second part of the paper, we analyze the trade-off between energy efficiency and quality of experience at the end user. The results reveal that a provider's service control measures do not only reduce the operational costs of the network but also bring a second benefit: they help maximize the battery lifetime of the end-user device.
Service-Centric Networking
2011 IEEE International Conference on Communications Workshops (ICC), 2011
Content-centric networking is a novel paradigm for the Future Internet. This paper argues that co... more Content-centric networking is a novel paradigm for the Future Internet. This paper argues that content-centric net- working should be generalized towards a service-centric net- working scheme. We propose a service-centric networking design based on an object-oriented approach, in which content and ser- vices are considered objects. We show implementation architec- tures for example services and how these can benefit from
INVESTIGATION ON THE EVOLUTION OF AN INDOOR ROBOTIC LOCALIZATION SYSTEM BASED ON WIRELESS NETWORKS
Applied Artificial Intelligence, 2013
ABSTRACT This work addresses the evolution of an artificial neural network ANN to assist in the p... more ABSTRACT This work addresses the evolution of an artificial neural network ANN to assist in the problem of indoor robotic localization. We investigate the design and building of an autonomous localization system based on information gathered from wireless networks WN. The article focuses on the evolved ANN, which provides the position of a robot in a space, as in a Cartesian coordinate system, corroborating with the evolutionary robotic research area and showing its practical viability. The proposed system was tested in several experiments, evaluating not only the impact of different evolutionary computation parameters but also the role of the transfer functions on the evolution of the ANN. Results show that slight variations in the parameters lead to significant differences on the evolution process and, therefore, in the accuracy of the robot position.
Journal of Systems Architecture, 2014
ABSTRACT Abstract The application of pesticides and fertilizers in agricultural areas is of cruci... more ABSTRACT Abstract The application of pesticides and fertilizers in agricultural areas is of crucial importance for crop yields. The use of aircrafts is becoming increasingly common in carrying out this task mainly because of their speed and effectiveness in the spraying operation. However, some factors may reduce the yield, or even cause damage (e.g. crop areas not covered in the spraying process, overlapping spraying of crop areas, applying pesticides on the outer edge of the crop). Weather conditions, such as the intensity and direction of the wind while spraying, add further complexity to the problem of maintaining control. In this paper, we describe an architecture to address the problem of self-adjustment of the UAV routes when spraying chemicals in a crop field. We propose and evaluate an algorithm to adjust the UAV route to changes in wind intensity and direction. The algorithm to adapt the path runs in the UAV and its input is the feedback obtained from the wireless sensor network (WSN) deployed in the crop field. Moreover, we evaluate the impact of the number of communication messages between the UAV and the WSN. The results show that the use of the feedback information from the sensors to make adjustments to the routes could significantly reduce the waste of pesticides and fertilizers.
In this paper, the EuQoS Consortium offers its first architecture release in order to provide an ... more In this paper, the EuQoS Consortium offers its first architecture release in order to provide an initial view on how end to end QoS is provided over multiple and heterogeneous networks. The EuQoS end to end Architecture has two views; a network deployment view across a number of autonomous systems (AS) domains and a software view within an AS.
The provision of guaranteed Quality of Service (QoS) in the Internet requires appropriate system ... more The provision of guaranteed Quality of Service (QoS) in the Internet requires appropriate system support for both resource allocation and charging. Differentiated Services is an approach for the former which targets a high level of scal- ability. The inclusion of flow-based charging characteristics, such as QoS, extent of service usage and traffic destination dependencies, into Differentiated Service models requires specific
Communications of the ACM, 2012
wIR eLess senso R n eT woR Ks (WSNs) play a key role in the emerging "real-world Internet," with ... more wIR eLess senso R n eT woR Ks (WSNs) play a key role in the emerging "real-world Internet," with several large-scale WSNs being deployed; see, for example, Bernat 2 and Dudek et al. However, WSN development is inherently complex, involving hardware design, embedded and distributed programming, heterogeneity, scale, and unpredictable environmental changes. Addressing this complexity, testbed-based experimentation (recommended by Weiser 32 ) is increasingly the norm for developing and optimizing WSN systems in a controllable environment prior to deployment.