Paper Title, Authors, Abstract (Issue 1, Volume 4, 2010)

Pages

Estimation of Pause Length Set by Storyteller at Sentence Boundary in Nursery Tale: Design of Synthesized Speech to Support Listener's Comprehension
Hideji Enokizu, Kazuhiro Uenosono, Seiichi Komiya

Abstract: In the present study, we examined the pause length which the storyteller sets at each sentence boundary in the story text to support children’s comprehension and proposed one method of estimating the pause length preliminarily to apply to the speech synthesis. While reading the story text, the reader constructs the situation model that is the mental microworld described in each sentence. Unlike the reader who can read the text at his own pace, however, the listener must hear the story at the storyteller’s reading pace. Therefore we assumed that the experienced storyteller can set the pause length at each sentence boundary necessary for the listener to construct the situation model. If the listener is a young child, this assumption is true. Then we focused on the relationship between the mental operations for constructing the situation model and the pause length set by the experienced storyteller to help the listener comprehend the story. Specifically, we devised a knowledge representation with multilayered frame structure corresponding to the situation model to predict the mental operations for constructing the situation model. The knowledge representation was named as the situation frame. The results indicated that the storyteller controlled the pause length on the basis of several operations. The formula, that can estimate the pause length from the operation needed to construct the situation frame, seems to provide us the reasonable method to determine the pause length in the synthesized speech preliminarily.
 

Power Line Modelling for Creating PLC Communication System
P. Mlynek, M. Koutny, J. Misurec

Abstract: The article presents a design of the power line communication model. This model is composed of communication model, model of power line and noise model. The communication model is realized as the OFDM system, power line are modelled from transfer function of two-port network or from transfer function of multipath signal environment. Noise model are modelled as white noise, which gets a spectral colouring by a filter. On the resulting PLC communication model was shown comparison of different modulation technique and coding scheme. The different levels of mapping the carrier frequencies in OFDM were simulated on the proposed model from the viewpoint of comparing symbol error with signal to noise ratio and the interference effect to symbols rearrange in the constellation diagram were simulated as well.
 

Optical ZCZ Code Generators Using Sylvester-type Hadamard Matrix
Takahiro Matsumoto, Shinya Matsufuji

Abstract: In this paper, we propose the construction of two code generators for optical ZCZ codes of Zcz = 4n??2 with positive n and Zcz = 1 using the Sylvester-type Hadamard matrix, which are called ROM-type and non ROM-type code generators. The optical ZCZ code is a set of pairs of binary and bi-phase sequences with zero correlation zone. An optical code division multiple access (CDMA) system using optical ZCZ code can remove co-channel interference and influence of multi-path. This ROM-type code generator can be constructed by a ROM and an up-counter. Similarly, the non ROM-type code generator can be constructed by an up-counter and logic gates. The ROM-type and non ROM-type code generators are implemented on a field programmable gate array (FPGA) corresponding to 600; 000 logic gates, and the non ROM-type code generator can reduce logic elements and memory bits than the ROM-type code generator, and can operate faster than the ROM-type code generator.
 

Handoff Tactics for NEMO and Integrated Network
Hui-Min Huang, Jia-Lin Chang

Abstract: Our aims to revise the handoff method for NEMO and integrated 3G and NEMO network. These methods include horizontal handoff in NEMO and vertical handoff in integrated 3G and NEMO network. This paper took advantage of the NEMO’s characteristics to propose a novel horizontal handoff method. Beside, we adopt the conception of hierarchical network and propose HO to assist the vertical handoff. Our method decreases handoff latency, control packets and network latency for handoff. The simulation shows that the handoff latency be decreased by about 3000ms for horizontal handoff. The average result shows that our method decreases control packet by about 47.3% and network latency by about 38.7% for vertical handoff. The simulated results demonstrate our method is better than the traditional NEMO system.
 

    Paper Title, Authors, Abstract (Issue 2, Volume 4, 2010)

Pages

WiMAX Network Design for Cost Minimization and Access Data Rate Guarantee Using Multi-hop Relay Stations
Chutima Prommak, Chitapong Wechtaison

Abstract: Network cost and network quality of services are important concerns in the widespread deployment of WiMAX networks. This paper presents a novel network design and optimization model for mobile WiMAX access networks utilizing multi-hop relays. The proposed model aims to determine optimal locations of base stations and relay stations so that the network can guarantee quality of services in term of the access data rate and the service coverage to serve potential user traffic demand in the target service area. Numerical network design results demonstrate that the proposed model can improve the user access data rate up to 60% and enhance the network service coverage up to 12% compared with the other existing models in literature.
 

Modeling VoIP Traffic on Converged IP Networks with Dynamic Resource Allocation
Imad Al Ajarmeh, James Yu, Mohamed Amezziane

Abstract: The exponential growth of reliable IP networks provides a suitable and cost-efficient replacement for the legacy TDM based voice networks. In this paper we propose a new framework for modeling Voice over IP (VoIP) traffic based on a nonhomogeneous Poisson process (NHPP). We show that the NHPP can provide an exact fit for the call arrival data, and can also be approximated to a normal model under heavy traffic condition. The overall goal of traffic engineering is to minimize call blocking and maximize system resource utilization. Our study which is based on hundreds of millions of call arrival information shows that the Poisson process fails to model the traffic behavior of modern IPbased telecommunication systems. This failure is due to using fixed call arrival rate and static resource allocation scheme. Our proposed framework solves the two problems by modeling call arrivals as a function of time. This time-dependent function supports a dynamic resource allocation mechanism that can be easily applied to converged IP networks. The proposed model is validated by real traffic data, and is also applied to predict the behavior of future data. We conducted statistical tests which demonstrate the validity of our model and the goodness-of-fit of predicted data and actual data. Our statistical results also show that the NHPP can safely be approximated by a normal process under heavy traffic conditions.
 

A Compact Internal Planar Antenna with a Capacitive Tuner for 3G and 4G Mobile Phone Application
Cheng-Hung Lin, Kwong-Kau Tiong, Jwo-Shiun Sun, YD Chen, Guan-Yu Chen

Abstract: There have been many antenna designs studied and developed in 3G mobile phone application. Multiband operation has become a basic requirement for internal antennas to be used in the mobile phone for wireless communication system. These papers are evaluated the multiband antenna operation for the application in 3G wireless communication systems. In recent years, a 4G system is in development and expected to supply the better quality of data throughput operation. In this paper, a high performance planar antenna [1, 2] with a capacitive tuner as the primary radiator for 4G operation is presented. A prototype of the proposed planar antenna with a compact area size of 60mmx13mmx8mm is implemented, and the antenna shows a wide operating bandwidth of about 350MHz and 550MHz for low band and high band respectively, making it easy to cover the LTE700, CDMA850/1900, GSM850/900/1800/1900, and UMTS2100 bands for wireless communication for the 3G/4G systems in a mobile phone application. The multipath fading is a critical task in the wireless communication systems. In order to solve the problem; we consider the diversity technique in the system [3]. Therefore, a secondary antenna design with the receiver function used in the wireless communication systems is studied. The compact size of the secondary antenna is 60mmx7mmx8mm, and the antenna can generate three resonant modes to cover the CDMA850, CDMA1900, and UMTS2100 MHz for the system applications. The secondary antenna shows the bandwidth of about 210MHz and 360MHz for low band and high band bandwidth respectively. The study mainly focuses on the current trends in development of compact and low profile multi-media PDA and Smartphone, and provides planar antennas design suitable for application in 3G/4G wireless communicating systems [4, 5]. The proposed antennas are easily fabricated by the flexible planar antenna at low cost and embedded into the mobile phone. A 50 ohms microstrip line is used to excite the planar antenna. The performed data including return loss, antenna gain, current distribution and radiation patterns are presented [6, 7]. The SAR results of the proposed antenna are also analyzed in phantom head and body modes. The antenna design can have the high efficiency and low SAR value. All of the performances tell that the proposed antenna is proper to applied in the wireless communication system.
 

    Paper Title, Authors, Abstract (Issue 3, Volume 4, 2010)

Pages

Performance Improvement of a Wire Dipole using Novel Resonant EBG Reflector
C. Yotnuan, P. Krachodnok, R. Wongsan

Abstract: Electromagnetic band-gap (EBG) structure exhibits unique electromagnetism properties that have led to a wide-range application of electromagnetic devices. This paper presented the high-directive gain antenna consisting of a wire dipole, which is horizontally lied above the novel EBG structure. The structure of EBG would be as resonator and dipole's reflector that eliminate the surface waves at edges of reflector and the back lobe of this antenna, respectively. In addition, the near-field distribution inside gap is studied to show the different distances of gap, which influence to the resonant frequency, bandwidth, and directive gain of this antenna. Consequently, we have achieved a maximum directive gain of 9.06 dBi, which is higher than a dipole with traditional ground plane. The bandwidth for -10 dB is about 15.86% at the center frequency of 5.8 GHz. Since the proposed structure remains simple but it can provide higher directive gain and larger bandwidth covering the IEEE standard (802.11a/g), the antenna, therefore, is expected to be the low cost innovation for WLAN applications.
 

Anomaly Detection in Wireless Sensor Networks using Self-Organizing Map and Wavelets
S. Siripanadorn, W. Hattagam, N. Teaumroong

Abstract: This paper proposes an anomaly detection scheme which is able to detect anomalies accurately by employing only important features of data signals, instead of using all the sensor data traces. The contribution of this paper centers on anomaly detection by using Discrete Wavelet Transform (DWT) combined with a competitive learning neural network called self-organizing map (SOM) in order to accurately detect abnormal data readings while using just half of the data size. Experiment results from synthetic and real data injected with synthetic faults collected from a WSN show that the proposed algorithm outperforms the SOM algorithm by up to 18% and DWT algorithm by up to 35% in presence of bursty faults with marginal increase of false alarm rate. Furthermore, in the real-world datasets experiments show that our proposed algorithm can maintain acceptable anomaly detection accuracy as well as the SOM algorithm while using just half of the input data.
 

Entrepreneurship and its Effects on the Romanian Labour Market
Renata Nitu Antonie, Emoke-Szidonia Feder, Nicoleta Sirghi, Camelia Hategan

Abstract: In the conditions that, Romania has to assure the premises necessary to pass on the stage of innovation based competitiveness, must assert the most efficient capitalisation of the human capital in the economy, through the exploitation of the entrepreneurial spirit, of the creative and innovative qualities of the active population. In these circumstances, based on the research model of the entrepreneurial process, depending on the stage of economic development and on the competitive level of the country, the paper aims to identify, on one hand, the existing relations between the conditions of the entrepreneurial framework and entrepreneurship, and on other hand, the possible impacts of entrepreneurship upon the dynamics of the labour market. Through the research model we propose to identify the cause-effect relationship between entrepreneurship and labour market, with and without using time-lagged variables.
 

    Paper Title, Authors, Abstract (Issue 4, Volume 4, 2010)

Pages

The Analysis of the Error Estimation and Ambiguity of 2-D Time Difference of Arrival Localization Method
J. Vesely, P. Hubacek

Abstract: This article is focused on the analysis of the error estimation and the ambiguity of the TDOA (Time Difference of Arrival) localization method in the 2-D space. First, the algorithm of hyperbolic equations solution is presented as a background for a derivation of a covariance matrix. Next, the covariance matrix is derived in analytical form. Finally, the conditions of the covariance matrix solvability are shown. The analytical solution of the covariance matrix is the main contribution of this article.
 

Implementation of an Adaptive Synchronizing Protocol for Energy Saving in Wireless Sensor Networks
Dragos Mihai Ofrim, Dragos Ioan Sacaleanu, Bogdan Alexandru Ofrim, Rodica Stoian

Abstract: In this paper we present an efficient protocol intended to save energy inside wireless sensor networks, thus increasing their lifetime. We offer a detailed description of the network model, topology, energy management and data synchronization to properly evaluate the performance of the proposed Adaptive Synchronizing Protocol. We simulated the proposed protocol and measured the network lifetime which proved to be significantly improved compared to the lifetime of the networks using a Non-Adaptive Synchronization model.