Carpathian Journal of Electronic and Computer Engineering

Volume 4, Number 1 - 2011

Establishing direct connection between two remote wireless clients
B. Almasi - University of Debrecen/Faculty of Informatics, Debrecen, Hungary
Abstract: Wireless clients are usually placed into private address realm (private network) in the Internet. The clients in the private address realm are able to communicate to each other in the same private network, and using special boxes (NAT boxes) the clients can also communicate to the public internet. This solution "hides" the wireless clients from the outside public internet world: they are unreachable from the outside world, or from other private networks.
In special situations the requirement of the direct connection between two wireless clients (located in different private networks) may occur. One widely used solution for this kind of problem is the special configuration of the NAT boxes (called "port forwarding"), but also there are many cases, where the NAT box configuration is not allowed (e.g. the applied security policy does not allow it). In this paper we would like to introduce a software based solution for the mentioned situation: The solution (named UDPTUN) establishes a direct tunnel connection between two clients located in different private networks (without changing or touching the configuration of the NAT boxes).

Hardware Controllers for Data Acquisition with Usage in FPGA Implementation of Control Systems
, B. Alecsa and A. Onea Automatic Control and Applied Informatics Department, "Gheorghe Asachi" Technical University, Iasi, Romania
Abstract: This paper presents a method to design hardware interfaces for serial analog to digital (ADC) and digital to analog converters (DAC). Also, an architecture for hardware implementation of control systems based on these interfaces and handshake signals is proposed. The described hardware was implemented inside a Spartan-3E FPGA device, and a control system based on the deadbeat algorithm was implemented as a case study. The algorithm was applied to control the speed of a direct current (DC) motor. Simulation of the algorithm and experimental results prove the effectiveness of the hardware implementation.
The main contribution is the method for design of control hardware implemented in FPGA, using high abstraction level software tools.

The theoretical and experimental study of claw pole alternators
Author: Cristian BARZ, Department Electrical Engineering, Faculty of Engineering, North University of Baia Mare,,Constantin OPREA, Department Electrical Engineering, Faculty of Engineering, North University of Baia Mare.
Abstract: In spite of the large amount of papers covering topics related to wireless sensor networks, a comprehensive overview of hardware platforms used to implement the network nodes is missing. There are several papers presenting particular approaches to implement wireless sensor nodes, there are also a few papers giving a brief presentation of hardware platform evolution in the last decade. This paper gives a survey of available hardware platforms, overviews their sensing, computing and communicating capabilities and focuses on the devices used to implement these platforms.

An Overview of Hardware Platforms Used In Wireless Sensor Nodes
Attila Buchman, University of Debrecen, Faculty of Informatics, Department of Informatics Systems and Networks, Debrecen, Hungary
Abstract: This paper presents a distributed control scheme for microgrids operation, modeled as multi-agent system and distributed constraint optimization problem. The case study and algorithm present how the local decisions and the communications ability of the agents may provide solutions in the optimal and effective control of the microgrids.

The Study of Transient Regimes for a Shell-Type Transformer
O. Chiver, L. Neamt, M. Horgos, S. Oniga and A. Buchman, North University of Baia Mare/ Department of Electrical, Electronic and Computers Engineering, Baia Mare, Romania
Abstract: The transient no-load regime and transient sudden short-circuit regime, of a small power shell-type transformer, will be studied in this paper. Will be determined the current variation in the primary circuit both analytically and by numerical analysis based on finite elements method (FEM). The software used for study is MagNet, developed by the Infolytica Company.


Hardware Support for Fine-Grain Multi-Threading in LEON3
M. Danek, L. Kafka, L. Kohout, J. Sykora, U TIA AV C R, v.v.i., Signal Processing, Pod Voda renskou ve z i 4, Praha 8, 182 08, Czech Republic
Abstract: The article describes instruction set extensions for a variant of multi-threading called micro-threading for the LEON3 SPARCv8 processor. An architecture of the developed processor ispresented and its key blocks described - cache controller, register file, thread scheduler. The processor has been implemented in a Xilinx Virtex2Pro and Virtex5 FPGAs. The extensions are evaluated in terms of extra resources needed, and the overall performance of the developed processor is shown for a simple DSP computation typical for embedded systems.

Self-learning Semantic-distance-based Answering System with Automatic Morpheme Recognition
: L. Dudas, Department of Information Engineering, University of Miskolc, Miskolc, Hungary
Abstract: At the beginning of the 21st century humanity has accumulated a very large amount of static data and facts. The problem is to make it active, to produce knowledge. One of the keys to this is restructuring, representing data in a new way. The emphasis is on the dynamic associations between data elements. Instead of storing distinct atoms of knowledge the goal is to build up a network of facts and methods that mirrors the relations found among them in the world, moreover in the human brain. One of the difficult tasks in this endeavor is to capture the meaning. The most feasible knowledge representation method for this purpose is the semantic network. This powerful technique has its new Renaissance in our days. This article offers a new definition of the meaning of a sentence for a human and presents a simple technique for searching for sentences having meanings close to the meaning of a given sentence. In some languages the morpheme structure of words plays a particularly important role in this process. This paper presents an automatic morpheme learning technique integrated in the answering system, using the Hungarian language as an example. Keywords: NLP, self-learning, semantic distance, answering system, meaning, morpheme recognition.

On the Statistical Analysis of Wireless Sensor vs. Wired Data Network Traffics
Z. Gal, Service Center for Informatics, University of Debrecen, Debrecen, Hungary, Gy. Terdik, Faculty of Informatics, University of Debrecen, Debrecen, Hungary
Not only the infrastructure of Wireless Sensor Network (WSNs) and classical wired IP data networks are very different but the statistical characteristics of data flows transferred on these environments have technology specific features, too. Based on the dynamic evolution in the last years WSNs became important elements of the small physical sizednetwork architecturesand are included as basic components in the Internet of Things (IoT) new concept. The challenge to transmit packets on optimum wireless path with minimum energy consumption affects all layer (physical, data link, network, transport, application) services of the WSN protocol stack. Wireless IP data technologies like GSM/UMTS/WiFi/WiMAX are utilized with success in WAN/MAN networks in contrast with WSN, which is usable only for small distances and reduced transfer capacity of bytes. Because of the energy consumption minimization the channel access mechanism should be simple as much as possible. Classical IP traffics in LAN/WAN environment do not confront with consequences of the energy constraints. The MAC algorithms are much more sophisticated than for WSNs. The difference in the layer functions implies difference in the traffic characteristics of this two network types. In this paper WSN and IP WAN/MAN data flows are analyzed as time series. Thesensor data flows were collected with TinyDB tools at the Intel Berkeley Research lab in 2004. The high speed IP data flows are available from public database of TIER links1. These significantly different types of data flowsare investigated based on Levy flights modeling. Long range dependence, self-similarity aspects of the inter-arrival time and the epoch ID time series are studied with sophisticated statistical analysis methods.


Handling Event-Driven Scenarios in CPS Application Simulations
Madalin Gavrilescu, Gabriela Magureanu, Dan Pescaru and Ionel Jian, Politehnica University of Timisoara, Romania
Abstract: The development process of the embedded distributed applications raises specific issues which concern the academic research. One of them refers to the need of performing simulations as realistic as possible for the whole embedded system before deploying the application on the hardware devices. This approach enables error detection in early stages of development and predicts the network's behavior. In this case event-driven simulators are preferred over other types of simulators. This paper proposes an XML-based event-driven model specification of the distributed network, allowing the developer to describe specific simulation scenarios for the distributed application. It also proposes a reusable event oriented programming model for handling such event-driven scenarios independently of a specific simulation environment. The presented approach contributes to the reduction of the number of lines of code required for implementing a distributed application, by an average of 20% compared to the application implementation from scratch. In special situations the improvement can reach up to 45% compared to the classic simulation development process, depending on the application goals.

Pseudo Random Number Generation on FPGA
Tamas Herendi, University of Debrecen/Faculty of Informatics, Debrecen, Hungary.
Abstract: The aim of the present paper is to show the theoretical background of the construction of uniformly distributed (UD) pseudo random number (PRN) sequences with good properties and efficient implementation on FPGA.

Hardware Assisted IEEE 1588 Clock Synchronization for Linux Based Network Embedded Systems
Tamas Kovacshazy, Blint Ferencz, Budapest University of Technology and Economics, Department of Measurement and Information Systems, Budapest Hungary
Abstract: The paper introduces the IEEE 1588 Clock Synchronization technology primarily developed for Ethernet based Network Embedded Systems and presents a hardware assisted PTP implementation for the Linux operating system (kernel version of 2.6.30 or later) on the x86 architecture. Our software is based on the standard PTPd available for UNIX like operating systems offering only software time stamping. The modified software uses the Linux standard SO_TIMESTAMPING socket option to communicate with the Ethernet Network Interface Controller driver, so it is supposed to work with any other Ethernet Interface Controllers with proper driver support. Our test system utilizes selected Gigabit Ethernet Interface Controllers supporting hardware time stamping donated by Intel. The initial results show that clock accuracy (masterslave clock difference) less than one microsecond is achievable with our software even in the case of high network traffic and slave node (a node that synchronizes its clock to a master clock) load in standard Linux. The paper also investigates how the coefficients of the clock servo influence initial time convergence and tracking behavior in case of disturbance such as changing network traffic and slave node load.


Intelligent thermometer with speech function implemented in FPGA
C. Lung ,North University of Baia Mare/Electronic and Computer Engineering, Baia Mare, Romania
Abstract: This paper presents the design of an embedded system for the assistance of persons with handicaps, implemented into the Spartan 3E Starter Board. The unit is defined in VHDL, and it targets a Xilinx Spartan-3E FPGA. Some of the modules are generic and can be easily reused without changes in other designs. The circuit was designed on a Windows XP PC using Xilinx ISE12.3 CAD tool. The main goal of this project is to implement a embedded system, which is able to control wireless ZigBee networks, read temperature from remote sensors and say this value using digital speech synthesizer implemented in FPGA.

Energy Monitoring of Mobile Voice Communications
Author: M. Marcu, and C. Milos, "Politehnica" University of Timisoara/ Faculty of Automation and Computers, Timisoara, Romania
Voice communication remains one of the main functions of mobile devices even though new features and applications are available. Currently there are a lot of voice communications technologies running on different types of mobile devices. The multitude and complexity of devices that implement a large spectrum of multimedia and wireless communication protocols require closer evaluation and understanding in respect to their energy efficiency. In this work we tried to identify, model and estimate the energy consumption of voice communications on mobile devices. We used TAPI (Telephony API) to identify ongoing and incoming calls and next to estimate their energy consumption.

Design and Analysis of FSO Systems Using the Software Package "FSO System Simulator (FSO SystSim)" - Statistical Model
P. Misencik, J. Turan , L. Ovsenik, Department of Electronics and Multimedia Communications, Faculty of Electrical Engineering and Informatics, University of Technology Kosice, Leta 9, 042 00 Kosice
Abstract: - This paper deals with the modeling of Free Space Optics (FSO) communication links using the software package "FSO SystSim", which was designed and implemented at KEMT FEI TUKE. Simulation of FSO communications links is of great importance in designing and understanding the context of such connection, depending on various parameters, both technical and constantly changing atmospheric parameters of the transmission optical channel. Paper briefly describes the statistical model used in this programming tool, and describes experiments carried out by the FSO SystSim.

Design and Analysis of FSO Systems Using the Software Package "FSO System Simulator (FSO SystSim)" - Steady Model
P. Misencik, J. Turan and L. Ovsenik Department of Electronics and Multimedia Communications, Faculty of Electrical Engineering and Informatics, University of Technology Kosice, park Komenskeho 13, 042 00 Kosice
Abstract:This paper describes a software package FSO System Simulator (FSO SystSim) which was designed and implemented at KEMT FEI TUKE. Simulation of FSO communication link is of great importance in designing and understanding the context of such connection depending on various parameters (technical and constantly changing atmospheric parameters of the transmission optical channel). Paper briefly describes the static model used in this programming package and describes experiments carried out by the FSO SystSim.

Corrected Simple Solar Irradiance Model for Mono-Si Photovoltaic Potential Estimation
L. Neamt, North University /Department of Electrical, Electronic and Computer Engineering, Baia Mare, Romania, Mirela Coman, North University /Department of Preparation, Geology and Environmental Engineering, Baia Mare, Romania.
Abstract: Photovoltaic (PV) systems are important alternative for fossil fuel resources conversion. The minimum environmental impact, maintenance, the availability of solar energy, and the technological level achieved are some advantages of conversion from solar to electrical energy. Calculation of PV potential is, these days, mainly tributary to solar maps or databases. A simplified model, with general application and having a comparable accuracy with above mentioned methods, is a useful tool for designers. The input data for corrected method are the geographical parameters of the site and the temperatures recorded by meteorological stations; the solar radiation data are not needed (these data are not usual data recorded by meteorological stations). At the end of the work the PV potential for Baia Mare City was determined using temperature data recorded by North University Meteorological Station..


Hardware Implemented Neural Networks used for Hand Gestures Recognition
S. Oniga, University of Debrecen/Informatics Systems and Networks, Debrecen, Hungary,, I.Orha, North University of Baia Mare/Electronic and Computer Engineering, Baia Mare, Romania,
Abstract: This paper presents hardware implementation of Artificial Neural Networks (ANN) that are used for human hand's natural gestures recognition. Main goal of this project is to implement a recognition system that recognizes data gathered from various sensors placed on a bracelet. This easy to use interface can be used even by elderly or impaired people to control electronic/electric devices only with hand gestures.

Alternative control method of the smart house: natural gestures
Stefan Oniga, Osan Anca Roxana, Alexan Alexandru Iulian, North University of Baia Mare, Romania
Abstract: - Due to the rapid increase of house automation use it is clear that alternative methods of control are needed. This paper presents a control method based on the person's gestures that allows a high degree of control especially on devices that have binary states (on/off). The gesture based interface is suitable for the control of the smart house because it offers a simple yet powerful control mechanism that is appropriate even for children, elderly persons and persons with disabilities due to the intuitive interface. In order to test the functionality of this control method, a smart house control system has been implemented. A bracelet has been implemented using the C language into an Atmega168 microcontroller based board. This bracelet is capable of sensing hand movements, and with the help of a location identification system, even the person's location. The main control system has been implemented using VHDL into a Xilinx Spartan-3E FPGA and it is capable of domestic device control and GUI display.

On the Energy Constraint in Wireless Sensor Networks
M. Popa, G. Girban Politehnica University/Faculty of Automation and Computers, Timisoara, Romania
Abstract:- Wireless Sensor Networks (WSNs) is one of the most promising technologies in our days. They can be found in a wide area of applications from domestic to military ones. A WSN is made by a number of tiny battery powered sensor nodes, having sensing, processing and communicating possibilities. In most cases the replacement or replenishment of the batteries is difficult or impossible, so the energy is the main constraint in designing and maintaining WSNs. This paper presents an overview and taxonomy of the solutions for the energy constraint. They are divided in solutions for energy conservation and for energy replenishment. Next, the solutions are grouped in node level and network level. A section is foreseen for describing the authors' approach. It consists in software power consumption monitoring, at node level, during network employment. This information can be used for energy efficient communication and for strategies for conserving the energy at the node level.


Simple vision for microcontroller
Sebastian Sabou, Claudiu Lung , Ioan Orha North University of Baia Mare, Romania
Abstract: Using an microcontroller with interface to simple image sensor for simple visual processing algorithms or as simple interface RS232 sensor connection.

Effect of Internet on Societies
Ali A. Sakr, Faculty of Engineering, Kafrel-Sheikh University, Egypt,
Abstract:The Internet affects the behavior of the young generations, it causes a mixture of virtual publicity, amentia and idiopathy. Internet addicts suffer some radiation defects due to their long sessions, this may result in blood ionization, leukemia or eye cataract. The paper presents a statistical study on health engineering concerning the effects of Internet on the Arab Society. It presents also some guides for a better Internet use.

Investigating the Precision of the TSC-based Packet Timestamping
Tamas Skopko, Peter Orosz, University of Debrecen/Faculty of Informatics, Debrecen, Hungary
Abstract: With the emergence of gigabit per second and higher bandwidth networks, software based packet capturing faced severe performance challenges in two areas: lossless packet acquisition at high arrival rate and high precision timestamping. Many research projects proposed hardware based network monitoring solutions in order to eliminate these performance bottlenecks. In contrast, the common microsecond resolution software based packet processing has not been enhanced to meet the measurement requirements of high performance networks. In a previous paper, we already proposed an alternative packet capturing solution that is based on the libpcap library and supports 10-9 second resolution timestamping. We are now evaluating the performance of the proposed solution in practice. Experimental evidence shows that our approach represents the inter-arrival times of the incoming packets with a higher precision since the measured time values are generated with a lower overhead and stored in the native resolution.


Holistic modelling of a combined Photovoltaic, Wind and Fuel Cell power system
A. Tisan, M. Cirstea, Anglia Ruskin University, Cambridge, UK
Abstract: The research work presented in this paper is focused on the holistic modelling of a combined Photovoltaic (PV), Wind and Fuel Cell, (FC) power system. The modelling approach is based on the Handel C programming language and is using the DK5 modelling / design environment from Mentor Graphics. The aim of the research was to achieve a combined model of a photovoltaic - wind-fuel cell energy system, enabling an holistically optimized digital control system design, followed by its rapid Field Programmable Gate Array (FPGA) prototyping. Initially, the functional simulations of the integrated system were performed, than, the controller design was downloaded in hardware onto a RC10 development board containing a Xilinx Spartan FPGA and was successfully tested experimentally. This approach enables the design and fast hardware implementation of efficient controllers for Distributed Energy Resource (DER) hybrid systems.

Inverse Mojette Transform Implementation and the MTTool
Vasarhelyi Jozsef,University of Miskolc/Department of Automation and Communication Technology, Miskolc, Hungary, Turan Jan, University of Kosice, Department of Electronics and Multimedia Communications, 041 20 Kosice, Slovak Republic, Szoboszlai Peter, Magyar Telekom Plc., Budapest, Hungary
Abstract:The Mojette Transform (MOT) is originated from France introduced by J-P. Guedon. There are several different variations of MOT applications nowadays which are used in different areas such as tomography, internet distributed data bases, encoding, multimedia error correction, or The Mojette Transform Tool (MTTool) which was created for testing purposes, etc. This paper presents the some aspects of the MTTool and IMOT implementation The logic circuitry of the IMOT compared with the MOT shows that the reconstruction process is more complicated. The MOT and IMOT hardware implementations are based on the sliding window method and the stepping window method.

The impact of servers breakdown on the performance of proxy cache servers
Tamas Berczes, Janos Sztrik, Faculty of Informatics, University of Debrecen, Hungary, Attila Hazy, Department of Applied Mathematics, University of Miskolc, Hungary.
Abstract: An open Jackson-type queuing network model is proposed to study the impact of the servers breakdown on the overall response times toWeb requests. The primary aim of the present paper is to modify the performance model of the Proxy Cache Server to a more realistic case when both the Proxy Cache Server and the Web server are unreliable. The main performance and reliability measures are derived, and some numerical calculations are carried out by the help of the MOSEL tool. The numerical results are graphically displayed to illustrate the effect of the non-reliability of the servers on the mean response time.