Issue 1, Volume 2, 2008

On the Level-Crossing Probability in a Queue with Autcorrelated Arrivals
by Andrzej Chydzinski, Lukasz Chrost

Abstract: In this paper the probability that the queue size is kept below some threshold in time interval of a given length is studied. In particular, a formula for this probability is shown in terms of generating functions. In addition to analytical results, a set of numerical results is presented. These numerical results reveal a surprising phenomenon. Namely, when the arrival process is strongly autocorrelated, the level-crossing probability may depend very little on the system load. As IP traffic is often strongly autocorrelated, it is likely that this phenomenon may be observed in queues of packets in Internet routers.

Keywords:
Level-crossing probability, single-server queue
Full Paper, pp. 1-9

A Source Code Generator Based on UML Specification
by Kresimir Fertalj, Mario Brcic

Abstract: This paper presents a application generator based on UML specification. The tool is capable of generating the source code in various programming languages from the same specification. The main characteristics of the existent tools are explained in brief. Main generator capabilities and merits are presented as well as an example of usage based on a relatively simple scenario. The tool extensibility is described as a mean of making the tool to suit a wide range of needs.

Keywords:
Application generator, CASE, source code templates, UML, XML/XSL transformations
Full Paper, pp. 10-19

A Novel Method to Modify VAD used in ITU-T G.729B for Low SNRs
by H. Farsi, M. A. Mozaffarian, H. Rahmani

Abstract: Voice Activity Detection (VAD) Systems have various standards. One of the famous and practical standards is ITU-U G.729B. In G.729B, VAD decision, compare with other standards and new methods, has poor performance for voice frames especially in low Signal-to-Noise Ratios (SNRs). However, since this standard has good properties that we try to modify its low performance in adverse environments. One point that we focus on this standard is trying to have minimum changes. Therefore we use some new methods without major modification on basic structure. In this methodology we use some parameters in the first part and connect it to the main block.
We compare the proposed method, using objective parameters, with basic version of G.729B standard and ETSI AMR option 1 and 2. This comparison study in various types of noises like Gaussian, Vehicle and Babble noise.

Keywords:
Geometrically Adaptive Energy Threshold, LPFing method, Periodicity Estimation, True Envelope LPC, Voice Activity Detection
Full Paper, pp. 20-29

Performance Analysis of TCP Congestion Control Algorithms
by Habibullah Jamal, Kiran Sultan

Abstract: The demand for fast transfer of large volumes of data, and the deployment of the network infrastructures is ever increasing. However, the dominant transport protocol of today, TCP, does not meet this demand because it favors reliability over timeliness and fails to fully utilize the network capacity due to limitations of its conservative congestion control algorithm. The slow response of TCP in fast long distance networks leaves sizeable unused bandwidth in such networks. A large variety of TCP variants have been proposed to improve the connection’s throughput by adopting more aggressive congestion control algorithms. Some of the flavors of TCP congestion control are loss-based, high-speed TCP congestion control algorithms that uses packet losses as an indication of congestion; delay-based TCP congestion control that emphasizes packet delay rather than packet loss as a signal to determine the rate at which to send packets. Some efforts combine the features of loss-based and delay-based algorithms to achieve fair bandwidth allocation and fairness among flows. A comparative analysis between different flavors of TCP congestion control namely Standard TCP congestion control (TCP Reno), loss-based TCP congestion control (HighSpeed TCP, Scalable TCP, CUBIC TCP), delay-based TCP congestion control (TCP Vegas) and mixed loss-delay based TCP congestion control (Compound TCP) is presented here in terns of congestion window verses elapsed time after the connection is established.

Keywords:
Congestion control, High-speed networks, TCP
Full Paper, pp. 30-38

Issue 3, Volume 2, 2008

Improvement Program for Heat Balance Analysis Fuel to Steam Efficiency Boiler and Wireless Transducer Controlled
by Nattapong Phanthuna, Thaweesak Trongtirakul

Abstract: This research is mainly purposed two objects, firstly, to improves and applies the sensors that were installed before with the PIC18F458 microcontroller at 2.4 GHz of frequency. Lastly, to increase the efficiency of combustion system processes in the industrial groups by heat balance analysis with wireless transferring. As a result of, both objectives can be advantages such increase the efficiency of steam generating, reduce the costs, and friendly environment. The results that the efficiency has been raised by 15 – 25% and can transfer into MESH network successfully.

Keywords:
Wireless Data Transferring, Cogeneration energy, Boiler, Heat Balance
Full Paper, pp. 69-76

Processing Data for Colored Noise using a Dynamic State Estimator
by Marius-Constantin O. S. Popescu, Onisifor V. Olaru, Nikos E. Mastorakis

Abstract: This paper treats data reduction in array processing for the spatially colored noise case. The purpose is to reduce the computational complexity of the applied signal processing algorithms by mapping the data into a space of lower dimension by means of a linear transformation. We discuss ways to implement the transformation and show that it suffices to estimate the array covariance matrix instead of the noise covariance matrix in the design process of the optimal transformation. Computer simulations are given that illustrate the problem of interference from out-of-band-sources that result when a beamspace transformation is designed to focus on a particular sector. The presents an dynamic state estimator. The method uses ANN based bus load prediction for the prediction step in the DSE.

Keywords:
Adaptive data reduction, colored noise, dynamic state estimation, load prediction
Full Paper, pp. 77-86

Empirical Results for the use of Facial Expressions and Body Gestures in e-learning Tools
by Marwan Alseid, Dimitrios Rigas

Abstract: In this paper, an empirical study investigating the use of avatars as virtual lecturers in e-learning interfaces is described. The primary focus is to present and discuss the experimental results related to users’ views and evaluations of individual facial expressions and body gestures used in the experimental e-learning tools in both the presence and absence of interactive context. Three different e-learning platforms were built to be tested in the experiment each of which used a human-like avatar as a virtual lecturer in the presentation of three different lessons about class diagram notation. The experiment has been carried out employing the within-subject approach with 48 users each of them participated individually. The obtained results demonstrated the importance of specific expressions and gestures that can be used by virtual lecturers in e-learning tools to improve users’ motivation and interest about the presented learning material. These results highlighted the need for further research to evaluate more facial expressions and body gestures.

Keywords:
Avatar, Body gestures, E-Learning, Facial expressions, Multimodal metaphors, Usability
Full Paper, pp. 87-94

Issue 2, Volume 2, 2008

An Adequate Design for Large Data Warehouse Systems: Bitmap Index Versus B-Tree Index
by Morteza Zaker, Somnuk Phon-Amnuaisuk, Su-Cheng Haw

Abstract: Two of the most common processes in database design community include data normalization and denormalization which play pivotal roles in the underlying performance. Today data warehouse queries comprise a group of aggregations and joining operations. As a result, normalization process does not seem to be an adequate option since several relations must combine to provide answers for queries that involve aggregation. Further, denormalization process engages a wealth of administrative tasks, which include the documentation structure of the denormalization assessments, data validation, and data migration schedule, among others. It is the objective of the present paper to investigate the possibility that, under certain circumstances, the above-mentioned justifications cannot provide justifiable reasons to ignore the effects of denormalization. To date, denormalization techniques have been applied in several database designs one of which is hierarchical denormalization. The findings provide empirical data that show the query response time is remarkably minimized once the schema is deployed by hierarchical denormalization on a large dataset with multi-billion records. It is, thus, recommended that hierarchical denormalization be considered a more preferable method to improve query processing performance.

Keywords:
Data warehouse, Bitmap index, B-tree index, Query processing
Full Paper, pp. 39-46

An Effective Early Detection System for the Potential Marketable Items from the Initial Learning Datasets
by Masakazu Takahashi, Kazuhiko Tsuda

Abstract: It is hard to detect the potential marketable items from the transaction data, all the more distinguish the marketable ones or not among the new released items. Concerning to the conventional extracting method is base on the item time-series analyses of the same category. On the other hand, one of the extraction methods for the issue is to make use of the recommendation algorithms. As for the recommendation functions, although the conventional recommendation system is in common among the Internet businesses, those engines provide the proper results; therefore, there need to improve recommendation algorithms. From those research backgrounds, this paper, we focus on detecting algorithms analyses for the marketable item among the new released items with improvement of the recommendation engine. We have gathered the ID (Identification)-POS (Point-Of-Sales) data from a local grocery store in Japan, and defined the index of the trend leader with the criteria for the day and the sales number.?From the analysis of the gathered data, we have extracted trend leaders among the customers. Using the results of the recommendation engine, we are able to make detailed decisions in the following three points: 1) to make appropriate recommendations to the other group member based on the transitions of the trend leaders' preferences; 2) to evaluate the effect of the recommendation with the trend leaders’ preferences; and 3) to improve the retail management processes: prevention from the stock-out, sales promotion for early purchase effects and the increase of the numbers of sales.

Keywords:
Collaborative Filtering System, Customer Preference, Dual-Directed Recommendation, Recommendation Systems, Service Science and Management Engineering
Full Paper, pp. 47-58

A Usability Evaluation of Multimodal Metaphors for Customer Knowledge Management
by Mutlaq B. Alotaibi, Dimitrios I. Rigas

Abstract: Many factors explain why customers are reluctant to exchange knowledge, but this paper places emphasis on the influence of designing interactive interfaces. The paper describes an empirical investigation carried out to evaluate the usability of incorporating multimodal interaction metaphors into Electronic Customer Knowledge Management Systems (E-CKMS) interfaces. To address this aim, a comparative evaluation was conducted on three E-CKMS interaction modes designed for this study. The control condition was text with graphics E-CKMS (VCKMS), and the experimental conditions were both multimodal. The multimodal platforms used a combination of speech, earcons, and auditory icons (MCKMS), and another combination of speech, earcons, and avatars with facial expressions (ACKMS). Three independent groups of users (n=20 for each group) evaluated the three platforms by performing eight common tasks of three different types and increasing complexity. Results suggested that the experimental conditions were more usable than the control in terms of efficiency and user satisfaction.

Keywords:
Expressive Avatars, Facial Expressions, Usability Evaluation, Customer Knowledge Management
Full Paper, pp. 59-68

Issue 4, Volume 2, 2008

On the Enhanced Hyper-hamiltonian Laceability of Hypercubes
by Tsung-Han Tsai, Tzu-Liang Kung, Jimmy J. M. Tan, Lih-Hsing Hsu

Abstract: A bipartite graph is hamiltonian laceable if there exists a hamiltonian path between any two vertices that are in different partite sets. A hamiltonian laceable graph G is said to be hyperhamiltonian laceable if, for any vertex v of G, there exists a hamiltonian path of G?fvg joining any two vertices that are located in the same partite set different from that of v.

Keywords:
Path embedding, Hamiltonian laceable, Hyperhamiltonian laceable, Interconnection network, Hypercube
Full Paper, pp. 95-101

Emotional Agents in Computer Games
by Khalil Shihab, Nida Chalabi

Abstract: In this paper, we consider emotion as a factor in the decision-making process and actions taken by an agent can be represented by a model, called "emotional model" created with specific focus on computer games development. It is designed to explore people’s behavior in certain circumstances, while under specified emotional states. Special attention was given to the thought process and actions displayed in the hypothetical scenarios. We characterized thoughts and actions associated with each scenario and emotional state. Each particular action or proof of steps taken in the thought process was given a percentage value directly proportional to answers given by the test population. Finally, we developed an experimental game program for the evaluation of our emotional decision making model. The aim of the evaluation was to find out how real life agents reacted in certain situations and what processes the human mind runs through when thinking and acting upon certain situations.

Keywords:
Emotional Model, Computer Game, Evaluation, Intelligent Agents
Full Paper, pp. 102-107

A Study into Fostering Entrepreneurship in Information Communication Technology (ICT)
by Geoff D. Skinner

Abstract: The paper details the findings of a recent research project in the realms of Information and Communication Technologies (ICT) and Innovation Management. The major issues considered by the project included: investigation of the possible inherent entrepreneurial nature of ICT; how to foster ICT innovation; and examination of the inherent difficulties currently found within the ICT industry of Australia in regards to supporting the development of innovative and creative ideas. The study was completed over a twelve month period with a focus on Internet technologies and their related innovators. The results of the research, included herein, have provided a number of unique contributions to the field in addition to a set of successful industry perspectives on ICT innovation. In particular how to manage and increase the opportunities for an entrepreneur in Australia to continue economic growth in the ICT sector.

Keywords:
Information and Communication Technology, Collaboration, Technological Innovation, Entrepreneurship, Technical Creativity
Full Paper, pp. 108-116