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ISSN: 1998-4480
Year 2011
All papers of the journal were peer reviewed by two
independent reviewers. Acceptance was granted when both
reviewers' recommendations were positive.
Main
Page
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.
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1-9 |
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.
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10-17 |
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.
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18-25 |
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.
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26-35 |
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.
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37-44 |
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.
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45-52 |
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].
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53-60 |
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.
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61-68 |
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.
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69-78 |
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.
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79-86 |
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.
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87-94 |
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.
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95-102 |
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.
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103-114 |
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.
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115-122 |
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.
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123-131 |
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.
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132-140 |
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.
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141-148 |
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.
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149-156 |
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.
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157-164 |
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.
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165-174 |
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.
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175-182 |
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