Paper Title, Authors, Abstract (Issue 1, Volume 5, 2011)

Pages

Application of the Classical Reliability to Address Optimization Problems in Mesh Networks
Louis A. Petingi

Abstract: In this paper we address optimization problems in wireless networks, specifically tailored for mesh networks, via the application of a classical network reliability measure. In classical reliability theory, a communication network can be modeled as a directed graph G=(V,E), composed of a finite set V of nodes, and a finite set E of links, where the links of the network underlying graph fail independently with known probabilities (nodes are perfectly reliable). Given a set K of terminal nodes and a source node s of K, the Source-to-K-terminal reliability, Rs,K(G), is the probability of the event that the source s will be able to communicate with the terminal nodes thru operational directed paths. Each link represents a stochastic wireless communication channel connecting two nodes of a network whose probability of failure is based upon recent results in Information Theory. We present efficient algorithmic techniques to tackle optimization problems in communication networks such as nodes’ redundancy and areas’ connectivity.
 

Virtual Output Queuing
V. Skorpil, P. Zednicek

Abstract: A new model of the active network element controlled by neural networks has been designed. They are described the Virtual Output Queuing Manager (VOQM) blocks in this paper. They manage and group together virtual output queues. The number of queues in each block depends on the number of ports. Each VOQM has been set a unique input port number which it serves and which is used for packet addressing. The settings are made using the graphical dialog, where you can assign the already mentioned port number, the maximum number of saved packages and their maximum length.
 

OCDMA Indoor Wireless Communications System with Mobile Receiver
Radu Lucaciu, Adrian Mihaescu, Calin Vladeanu

Abstract: In this paper we consider an optical code division multiple access (OCDMA) indoor wireless communication system using spectral encoding and evaluate its performances in cases of classical OCDMA, dynamic OCDMA and OCDMA with deconvolution. We present an analysis of the receiver movementinfluence on the indoor wireless communications system performances. As the receiver moves increasingly away from transmitter the amount of power received in that place will be getting smaller and system performances are affected. Knowledge of the impulse response in different positions in the room allows calculation of the amount by which power is lower at that point. We showed that increasing the power received in that place with the necessary amount, system performance are maintained at the same values, even if the receiver is moving away from transmitter. The bit error rate (BER) was estimated by means of simulations for several scenarios. The simulation results confirm the fact that using deconvolution in OCDMA systems, the multipath interference is reduced and the BER performances are significantly improved for diffuse configuration, as compared to the case without deconvolution.
 

Simulation Model for Performance Evaluation of Advanced SIP based Mobility Management Techniques
Rok Libnik, Gorazd Kandus, Ales Svigelj

Abstract: Wireless technologies have evolved very rapidly in recent years. In the future, operators will need to enable users to use communication' services independently of access technologies, so they will have to support seamless handovers in heterogeneous networks. In this paper, we focus on building the simulation modelfor testing advanced handover procedures. Simulation model based on real operator network measurements was presented, verified and validated. In addition, advanced procedure for SIP based seamless handover in heterogeneous network using congestion detection was described. Its performance was evaluated using the described simulation model. The results have shown that, by using the CAHP C procedure, we can significantly improve the user experience for VoIP application when performing seamless handover in heterogeneous networks.
 

    Paper Title, Authors, Abstract (Issue 2, Volume 5, 2011)

Pages

J-PAKE Based Mutual Authentication Model for EPC Networks
Cristina-Elena Vintila, Victor-Valeriu Patriciu, Ion Bica

Abstract: The LTE architectural model developed by 3GPP proposed solutions to achieve high data rates, lighter network architectures and easier achievement of security requirements. Designed as a fully sustained IP network, the LTE provides unified access to a variety of services networks, via its EPC component. The core network of this LTE/4G architecture is designed to facilitate faster and more secure access to the services desired by the user, while providing a high level of predictability, control and charging for the services accessed. 4G architecture was designed in such a manner that it is also interoperable with existing 3G systems, as well as with non-3GPP systems. When describing such a flexible design, the security constraints cannot be neglected. The access to this 4G network is permitted only in a secure manner. The security of this network is based on its 3G predecessor and is no longer compatible with the 2G system. This paper reviews some of the most command access solutions and model proposed for the 4G core network access. While describing the various designs, it also realizes a comparison between the models proposed and providing capture samples when available. In the second part, the paper proposes an authentication and key exchange model based on the J-PAKE algorithm and analyzes the security areas that can be improved if this model is used, along with its areas that need to be improved.
 

Mutual Coupling of Near Collocated Monopoles
Motti Haridim, Boris Levin, Michael Bank, Yoav Trabelsi, S. Tapuchi

Abstract: The electrical characteristics of two monopoles with different lengths located in the near region of each other are analyzed. The self and mutual impedances of both radiators are calculated, the mutual coupling between two monopoles is considered. It is shown that as in the case of two monopoles with equal lengths the structure of two monopoles with different lengths can be modeled as a combination of two-wire transmission line and monopole with stepped change of equivalent radius. The current distribution along each conductor is found. Also the method is applied to the multiplewire radiator. Calculations are based on the folded dipoles theory, on the theory of electrically coupled lines located under ground, and on the superposition principle.
 

Physician Burnout in General Practitioners Reflections upon Prevention and Treatment
Susanne Fuchs, Elke Mesenholl-Strehler, P. C. Endler

Abstract: Austrian general practitioners in the medical profession were the subject of a survey based upon the Maslach Burnout Inventory and supplementary items (Tirol, 95 respondents). The term "burnout" refers to emotional and physical exhaustion, apathy, cynicism, a reduced sense of work satisfaction and social withdrawal, which – apart from internal factors – may be caused by work overload, a lack of ―control? options, i.e. self-determination, inadequate financial compensation, a breakdown of social community, absence of fairness or conflicting values. The boundary between the concepts of burnout and depression is hard to demarcate. The former originated in the field of psychoanalysis but was subsequently expanded through insights from sociology. More than one third (35.8%) of respondents considered themselves to be at risk for burnout, with 27.2% showing elevated values for emotional exhaustion, 3.2% for depersonalisation and 10.0% for cynicism. The average values lay outside of the range which might warrant therapeutic intervention, however. The study did not reveal any noteworthy correlations based upon either age or gender (p > 0.05). Medical professionals licensed under the national health insurance plan tended to evidence higher degrees of burnout than did professionals practicing outside this framework (―physicians of choice?), as did those practicing in smaller communities. Availment of supervision services and participation in depth-psychologically oriented Balint groups had a favourable effect on the degree of burnout (10% lower values for cynicism, p < 0.01; - 10%; 6.5% higher values for personal accomplishment, p < 0.01). The results were compared with other studies about general practitioners and studies about other occupational groups. Specifics of physician burnout are presented and discussed including various prevention measures and treatment. It seems necessary to facilitate and implement further study, using standardized as well as larger sample sizes. In order to find sustainable methods to fight burnout, long-term surveys are considered to be indispensable. This article is based on an initial study report published in German in the Wiener Medizinische Wochenschrift [1]. The authors thank the WMW for their permission to publish the present expanded version of this report. The research work was carried out at the Interuniversity College Graz, Castle of Seggau, Austria within the framework of a study program focusing on group analysis [2,3].
 

The Influence of Doppler Effects in HAP-OFDMA Systems
Michael Bank, S. Tapuchi, M. Haridim, Miriam Bank, B. Hill, U. Mahlab, J. Gavan

Abstract: We consider the impact of Doppler frequency shift on the Orthogonal Frequency Division Multiple Access (OFDMA) signal and Frequency Bank Signal (FBS) transmitted over High Altitude Platforms ( HAPs). Theoretical analysis and simulations show that OFDMA systems perform well when the Doppler frequency shift is smaller than 2% of carrier frequency separation. These conditions correspond to operation frequency of 2GHz and train velocities up to 120 km/h. FBS method, on the other hand, allows working under more severe Doppler effects, namely a Doppler shift of up to 6 - 8 %, hence enabling higher carrier frequency bands and higher vehicle speeds.
 

Business Networks in the Internationalization of B-to-B-Services: Empirical Findings and Framework
Jukka Ojasalo, Katri Ojasalo

Abstract: This article aims at increasing the knowledge of business networks in the internationalization of b-to-b-services. The literature includes vast amount of knowledge of internationalization of a firm in general. A great deal of this literature is based on the concept of incremental stepwise internationalization process and empirical findings in manufacturing companies. So far, little knowledge exists of internationalization of b-to-b-services via business networks. Thus, there is a need to examine this are further. This article increases the knowledge by developing a framework which integrates the drivers and the process of internationalization of b-to-b-services. The drivers include both general drivers of services internationalization, as well as internationalization drivers from company’s domestic or international network. The process includes special characteristics of internationalization of b-to-b-services, decision to enter to foreign network, advantages and challenges of network approach, and ways of establishing relationships in foreign networks. The framework is based on literature analysis and empirical findings.
 

Using Self Organizing Neural Networks to Improve Optical Network Design
Alexandru Smeureanu, Stefan D. Dumitrescu, Liviu A. Cotfas, Andreea Diosteanu

Abstract: The paper presents a model for data (IP) communication network design that uses self organizing neural networks and graph theory adapted algorithms to improve its reliability and efficiency. The resulting architecture is a layered hierarchical network; the first layer represents the core of the network and has a ring topology while the second layer has a tree topology with a maximum depth constraint. The model is aimed towards providing a close to optimal solution for large problem configurations that are unsolvable in polynomial time.
 

    Paper Title, Authors, Abstract (Issue 3, Volume 5, 2011)

Pages

Communication Scheme based on the Concept of Media Biotope
Hidetsugu Suto

Abstract: A communication scheme is described that is based on the concept of “media biotope.” In this concept, communication medium structures are discussed using the analogy of an eco-biotope. In the proposed communication scheme, communities created using the local media are connected with and mutually affect each other. The local media revitalize local communities and help them keep their autonomy. The traditional scheme for communication media as described by Shannon and Weaver's is expanded in order to discuss the concept of media biotope. In the traditional scheme, an information sender and a receiver are required. In contrast, in the proposed scheme, the information sender is not defined, and receivers obtain information by observing and recognizing signs in the environment around them. Then, the properties of communication media, i.e., scale, connectivity, generality, and design, are discussed. In the concept of media biotope, the range of the medium must be comparatively small, and each community created through the medium should have connections. Many people should be able to freely participate in the mediums. Furthermore, these communities must be autonomous and stable like a bio-system created through an eco-biotope. Furthermore, examples of communication mediums designed for creating media biotope are shown.
 

Broadcasting and Routing Algorithms for the Extended OTIS-Cube Network
Jehad A. Al-Sadi

Abstract: This paper introduces a routing algorithm for the Extended OTIS-n-Cube Networks. The recently proposed network has many good topological features such as regular degree, semantic structure, low diameter, and ability to embed graphs and cycles. Broadcasting approaches such as constructing a Hamiltonian cycle, Spanning Tree, and One to all broadcasting are important aspects for any topology to embed due to the importance of broadcast messages within networks. This paper also presents such approaches for the extended OTIS-n-Cube Interconnection network. Examples are presented for different network sizes to show that broadcasting approaches for the Extended OTIS-n-Cube give better performance compared to similar approaches for the OTIS-n-Cube.
 

The Role of Simple and Common Technology in Welfare by Using the Internet
Hidetoshi Wakamatsu

Abstract: We discuss simple and common technology as a possible role of engineers in dealing with the various problems of the elderly and also the weak amid the changing society due to lengthening life-spans and declining birthrates. We first describe the conditions surrounding such people that they must face up to and interact with in their life-span. From several major social perspectives, what sort of welfare we wish to realize for the need of closely cooperative relationships with our belonging community. Under the evaluation of historical contribution of welfare technology taking into account of their limits and vulnerability, our approach is hereby discussed from a different policy with mainly securing the cultural backgrounds of individual persons in need, in which relating systems with multiple functions based on high-tech do not necessarily for their widespread use. Thus, we mention the importance of wide-area networks, featuring public benefits, easy replacement of old ones and convenience, in which our technology is marked by safety, reliability and flexibility. The Internet can be effectively used on policies of management including configuration for the cooperation because of its overall convenience with favorable economics and easy-to-handle equipment. We thereby present opinions from technical viewpoints that have been derived from our struggle with comprehensive engineering issues related to developing and practical utilization of basic functions for the beneficiaries. Although our argument and views cover some, not all, pertinent aspects, we will try to illustrate and advocate the roles and possibilities that we, the engineers, can play from the viewpoint of desirable progress in technology for welfare. Finally, we will mention the build-up of appropriate conceptual means for future welfare based on our simple and common technology.
 

The Future Solutions and Technologies of Public Safety Communications - DSiP Traffic Engineering Solution for Secure Multichannel Communication
John Holmstrom, Jyri Rajamaki, Taina Hult

Abstract: Importance of reliable telecommunication is constantly increasing. A new multichannel data communication concept presented in this paper, provides a uniform way to communicate over virtually any type of communications media in such a way that multiple, sometimes parallel communication paths appear as a single robust, uninterruptable, secure and reliable communication link between communicating peers. The solution named DSiP (Distributed Systems intercommunication Protocol) makes it possible to distribute all telecommunication among several operators and methods, resulting in a true multichannel communication system. The DSiP-multichannel routing solution increases reliability, security and integrity in telecommunication and allows regular communication methods to be used in mission critical telemetry systems. This is achieved by splitting risks between operators and communication channels; better routing and priority capabilities; taking security and intrusion risks into account; and adding modularity.
 

Intellectual Property Development through Informative and Persuasive Communication
Ion Petrescu, Camelia Stefanescu

Abstract: The paper suggests that the readers should look at how informative and persuasive communication influences the development of intellectual property. The more the informative and persuasive communication is practiced within an organization through a greater diversity of shapes, perfectly applicable to its activity field, quickly responding to its needs, the more the influence of communication on the development of intellectual property is positioned in a better balance.
 

Blind Channel Equalization in Impulse Noise
Rubaiyat Yasmin, Tetsuya Shimamura

Abstract: This paper presents a robust blind channel equalization technique in impulse noise environments. To suppress impulse noise effectively, the combination of order statistics (OS) and adaptive thresholding is considered. We implement nonlinear adaptation with the OS operation based on the Sato error criterion. The adaptive threshold is calculated using the variance of the input signal. Computer simulations demonstrate that a significant improvement in both the bit error rate and mean square error is achieved for communication channel models with a mixture of additive white Gaussian noise and impulse noise, in which two different impulse noise generation models with different noise generation probability are considered.
 

    Paper Title, Authors, Abstract (Issue 4, Volume 5, 2011)

Pages

Security of Transport Telematic Solutions
Tomas Zelinka, Miroslav Svitek, Zdenek Lokaj, Martin Srotyr

Abstract: Intelligent Transport Systems (ITS) solutions require availability of the secure seamless communications solutions and coverage of the widely spread areas is typically demanded. Different solutions require different levels of the telecommunications service quality. These parameters are linked with ITS service performance parameters used to quantify services parameters. Even though quite extensive range of wireless data services with reasonable coverage are provided by public telecommunications providers practically all services are provided with no guaranteed data service quality and security. ITS requirements can be better resolved if typically used public solution can be combined with both other public and private services where and when it is needed. Such solution requires implementation of the relevant flexible system architecture supported by the efficient decision processes. This paper is, however, primarily concentrated on the telecommunications security issues quantified by specific security performance parameter. Level of telecommunications service security depends on the ITS service requirement and its mutual relation is not typically trivial to be identified. "Car to Infrastructure" and "Car to Car" communication as well as vehicles on board data communication via Controlled Area Network (CAN) bus are areas with progressive growth of transferred data volumes. Such type of networking increase potential of the appearance of the intruder attacks, namely, if the security of the wide area networks is not carefully enough treated. Probability of hazards appearances principally grows if these networks are integrated in the dynamically organized wide area ones. That is also reason why relevant telecommunications security treatment is more and more understood as the crucial part of the ITS telecommunications solution. Besides of available “off shelf” security tools solution based on the non-public universal identifier with dynamical extension and data availability control according to the actor role or category is presented.
 

A 3-Dimensional Localization Algorithm for Mobile Wireless Multimedia Sensor Networks
Dragos Ofrim, Dragos Sacaleanu, Rodica Stoian, Vasile Lazarescu

Abstract: This article exposes a specific localization algorithm for Wireless Multimedia Sensor Networks. Its hybrid structure is designed for 3-dimensional positioning of the multimedia sensor nodes using in-situ measurements and minimizes the error of localization by proposing an efficient trajectory estimation pattern along with a periodic calibration of the sensor nodes’ coordinates. A periodic validation of the coordinates is performed by implementing a classical anchor-based localization algorithm. Providing a decreased error of localization, the suggested algorithm considerably reduces the localization delay, essential to mobile nodes, and offers an insignificant rise in network traffic as well as energy consumption throughout the positioning process. To further reduce the overall energy consumption, an adaptive sampling rate technique is proposed.
 

Increasing Lifetime in Grid Wireless Sensor Networks through Routing Algorithm and Data Aggregation Techniques
Dragos I. Sacaleanu, Dragos M. Ofrim, Rodica Stoian, Vasile Lazarescu

Abstract: The major problem for Wireless Sensor Networks (WSN) is the limited energy supply of the sensors. The research in this area is focused on making smaller sensors with low power consumption. Some of the most common techniques in prolonging the lifetime of the sensor network are data compression, routing algorithms, data aggregation, scheduling and synchronization. In this paper, an adaptive routing algorithm (ARA) suited especially for grid WSN is presented. The algorithm takes into account the residual energy of the sensor nodes and configures the paths in order to maximize the network lifetime. It also presented data aggregations techniques based on temporal and spatial correlation characteristic to for monitoring and data acquisition sensor networks. Tests were performed on an OmNET++ simulating platform, comparing ARA with already existing algorithms for grid WSN and highlighting the advantages of using the routing algorithm together with the data aggregation technique. Additionally, a test to determine the most energy effective place of the sink in the network and a comparison between square and hexagonal topology for WSN are performed.
 

Linearization of Doherty Amplifier with Second Harmonics and Fourth-Order Nonlinear Signals
Natasa Males Ilic, Aleksandar Atanaskovic, Bratislav Milovanovic

Abstract: In this paper, influence of the second harmonics and fourth-order nonlinear signals on the efficiency and linearity of three-stage Doherty amplifier loaded with harmonic control circuits is analyzed. Amplifier is designed with LDMOSFETs in carrier and peaking amplifiers with the same periphery and in periphery relations 1:2.5:2.5. The signals for linearization are extracted at the output of peaking cells. The carrier and peaking amplifiers are loaded with the harmonic control circuit that provides the optimal impedance for the signals for linearization and either an open or short circuit for the third harmonics. Analysis of three-stage Doherty amplifier linearization with the approach where signals for linearization are adjusted in amplitude and phase and inserted at both carrier cell input and output have been performed in simulation by ADS. Afterwards, the linearization technique effects to Doherty amplifier have been proofed experimentally on a standard two-way Doherty amplifier. Measurements of the third- and fifth-order intermodulation product suppression in case when the signals for linearization are included into the amplifier input have been carried out.
 

Optimization of FTTH Network in Kosovo through the Implementation of GPON Architecture and Analysis of the Cost of the Implementation
Nebi Caka, Astrit Hulaj

Abstract: Having regard to the fact that existing access networks in Kosovo are mainly based on copper wires, the access networks will present significant limitations in future in providing broadband services such as IPTV, video on demand, video games, videoconferencing, internet, distance learning, etc. One solution would be implementation of FTTH network in Kosovo as the access network. This would eliminate restrictions on the copper wire access network and should provide a safety network for a long period of time. There are several architectures and technologies of FTTH network, but as most appropriate and most favorable architecture and technology for implementation in Kosovo is proposed PON architecture, namely its GPON standard. This paper will analyze the advantages and disadvantages of the proposed architecture of PON, respectively GPON standard, and will be given the reasonableness of their implementation. It will analyze the concrete possibilities of practical implementation of a FTTH network in terms of Kosovo, depending on the location and the opportunities that exist for this realization. It will also analyze the implementation cost of a FTTH network, where as a model network for such analysis is used the connection of the 10 houses. At the end, will be analyzed and discussed the results of measurements performed for two wavelengths: λ = 1310 nm and λ = 1550 nm.