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Adaptation of the Kademila Routing for Tactical Networks, Journal of Telecommunications and Information Technology, 2011, nr 1
Get PDFIn this paper a modification of the widely used Kademlia peer-to-peer system to tactical networks is proposed. We first take a look at the available systems today to cover the range of possibilities peer-to-peer systems offer. We identify candidates for use in military networks. Then we compare two candidate systems in an environment with highly dynamic participants. The considered environment is focused on the special conditions in tactical networks. Then we give rationale for choosing Kademlia as a suitable system for tactical environments. Since Kademlia is not adapted to military networks, a modification to this system is proposed to adapt it to the special conditions encountered in this environment. We show that optimizations in the routing may lead to faster lookups by measuring the modified algorithm in a simulation of the target environment. We show also that the proposed modification can be used to extend the battery lifetime of mobile peer-to-peer nodes. Our results show that peer-to-peer systems can be used in military networks to increase their robustness. The modifications proposed to Kademlia adapt the system to the special challenges of military tactical networks
Web Services Efficiency in Disadvantaged Environment, Journal of Telecommunications and Information Technology, 2011, nr 1
Get PDFThe article presents results of web services (WSs) efficiency tests carried out in the testbed emulating disadvantaged network environment. The authors discuss the advantage of different WS adaptation techniques that allow to minimize the XML message size (i.e. compression, filtering and binary coding) and the size of JPEG image attachment (i.e., resolution reduction, decreasing colour depth, JPEG compression). The presented results show the efficiency of selected methods that adapt the web services realization to the possibilities of the network. The article is summarized by conclusions and recommendations in terms of sending XML SOAP messages in disadvantaged networks
Multi Queue Approach for Network Services Implemented for Multi Core CPUs, Journal of Telecommunications and Information Technology, 2011, nr 3
Get PDFMultiple core processors have already became the dominant design for general purpose CPUs. Incarnations of this technology are present in solutions dedicated to such areas like computer graphics, signal processing and also computer networking. Since the key functionality of network core components is fast package servicing, multicore technology, due to multi tasking ability, seems useful to support packet processing. Dedicated network processors characterize very good performance but at the same time high cost. General purpose CPUs achieve incredible performance, thanks to task distribution along several available cores and relatively low cost. The idea, analyzed in this paper, is to use general purpose CPU to provide network core functionality. For this purpose parameterized system model has been created, which represents general core networking needs. This model analyze system parameters influence on system performance
Active – Passive: On Preconceptions of Testing, Journal of Telecommunications and Information Technology, 2011, nr 3
Get PDFIn telecommunications and software engineering, testing is normally understood to be essentially active: a tester is said to stimulate, control, and enforce. Passive testing does not fit this paradigm and thus remains the niche research subject, which bears on the scope and depth of the obtained results. It is argued that such limited understanding of testing is one of its many community-bound preconceptions. It may be acceptable in the current engineering approach to testing, but can and should be challenged in order to converge on the core concepts of the proposed science of testing (“testology”). This methodological work aims at establishing that there are no fundamental reasons for admitting the dominant role of the active element in testing. To show this, external (also extra- technical) areas are consulted for insight, direct observations, and metaphors. The troublesome distinction between (passive) testing and monitoring, as well as unclear relations between testing and measurements, are also addressed
A Comparative Study of Single- and Dual-Threshold Voltage SRAM Cells, Journal of Telecommunications and Information Technology, 2011, nr 4
Get PDFIn this paper, a comparison has been drawn between 5 transistor (5T), 6T and 7T SRAM cells. All the cells have been designed using both single-threshold (conventional) and dual-threshold (dual-Vt) voltage techniques. Their respective delays and power consumption have been calculated at 180 nm and 65 nm CMOS technology. With technology scaling, power consumption decreases by 80% to 90%, with some increase in write time because of the utilization of high-Vt transistors in write critical path. The results show that the read delay of 7T SRAM cell is 9% lesser than 5T SRAM cell and 29% lesser than 6T SRAM cell due to the lower resistance of the read access delay path. While read power of 5T SRAM cell is reduced by 10% and 24% as compared to 7T SRAM, 6T SRAM cell respectively. The write speed, however, is degraded by 1% to 3% with the 7T and 5T SRAM cells as compared to the 6T SRAM cells due to the utilization of single ended architecture. While write power of 5T SRAM cell is reduced by up to 40% and 67% as compared to 7T SRAM, 6T SRAM cell respectively
Trends and Differences of Applying Intelligence to an Agent, Journal of Telecommunications and Information Technology, 2011, nr 4
Get PDFThe agent technology has recently become one of the most vibrant and fastest growing areas in information technology. On of the most promising characteristics of agent is its intelligence. Intelligent agent is the agent that percepts its environment, collects all information about its environment that it needs, processes these information and then generate proper actions according to these information. This paper discusses trends and differences between two main types of intelligence that can be applied to agent: accumulative intelligence and dynamic intelligence. Accumulative intelligence is discussed with its two perspectives: moment perspective and historical perspective. Auto-vehicle driver is also discussed as an application example of accumulative intelligence. Also, MOSAIC, Mimesis, and MINDY models are reviewed as the pioneering works of dynamic intelligence
Localization in Wireless Sensor Networks Using Heuristic Optimization Techniques, Journal of Telecommunications and Information Technology, 2011, nr 4
Get PDFMany applications of wireless sensor networks (WSN) require information about the geographic location of each sensor node. Devices that form WSN are expected to be remotely deployed in large numbers in a sensing field, and to self-organize to perform sensing and acting task. The goal of localization is to assign geographic coordinates to each device with unknown position in the deployment area. Recently, the popular strategy is to apply optimization algorithms to solve the localization problem. In this paper, we address issues associated with the application of heuristic techniques to accurate localization of nodes in a WSN system. We survey and discuss the location systems based on simulated annealing, genetic algorithms and evolutionary strategies. Finally, we describe and evaluate our methods that combine trilateration and heuristic optimization
Providing QoS Guarantees in Broadband Ad Hoc Networks, Journal of Telecommunications and Information Technology, 2011, nr 4
Get PDFThis paper presents a novel QoS architecture for IEEE 802.11 multihop broadband ad hoc networks integrated with infrastructure. The authors describe its features, including MAC layer measurements, traffic differentiation, and admission control. The modules required by the network elements as well as their integration are also presented. Additionally, the paper presents results which validate its correct operation and prove its superiority over plain IEEE 802.11. The authors are convinced that the proposed solution will provide QoS support for a variety of services in future mobile ad hoc networks
An Efficient Chaotic Interleaver for Image Transmission over IEEE 802.15.4 Zigbee Network, Journal of Telecommunications and Information Technology, 2011, nr 2
Get PDFThis paper studies a vital issue in wireless communications, which is the transmission of images over wireless networks. IEEE ZigBee 802.15.4 is a short-range communication standard that could be used for small distance multimedia transmissions. In fact, the ZigBee network is a wireless personal area network (WPAN), which needs a strong interleaving mechanism for protection against error bursts. This paper presents a novel chaotic interleaving scheme for this purpose. This scheme depends on the chaotic Baker map. A comparison study between the proposed chaotic interleaving scheme and the traditional block and convolutional interleaving schemes for image transmission over a correlated fading channel is presented. The simulation results show the superiority of the proposed chaotic interleaving scheme over the traditional schemes
Mobile Telematic Applications Based on Object Positioning, Journal of Telecommunications and Information Technology, 2010, nr 1
Get PDFGlobal positioning systems makes possible to build a new telematic systems, enabling various applications and services in many branches of economy. A special area of such applications are various transport and transport related tasks. Among them, of a high importance are applications applied to mobile objects, for example, to all kinds of vehicles, called mobile telematic services.The paper presents features of such a services, with a special emphasis of the services being fore- seen in Galileo satellite positioning system. Even conditions concerning such a service constructions are discussed, having in mind mainly necessity of complementary communications between a positioned object and related surrounding, including co-users of the movement area infrastructure as well as broader environment