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Advances in Hybrid Information Technology: 1st International Conference, ICHIT 2006, Jeju Island, Korea, November 9-11, 2006, Revised Selected Papers


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Taking Class Importance into Account

José-Luis Polo; Fernando Berzal; Juan-Carlos Cubero

In many classification problems, some classes are more important than others from the users’ perspective. In this paper, we introduce a novel approach, , to address this issue by modeling class importance through weights in the [0,1] interval. We also propose novel metrics to evaluate the performance of classifiers in a weighted classification context. In addition, we make some modifications to the ART classification model [1] in order to deal with weighted classification.

- Data Analysis, Modelling, and Learning | Pp. 1-10

Tolerance Based Templates for Information Systems: Foundations and Perspectives

Piotr Synak; Dominik Ślȩzak

We discuss generalizations of the basic notion of a template defined over information systems using indiscernibility relation. Generalizations refer to the practical need of operating with more compound descriptors, over both symbolic and numeric attributes, as well as to a more entire extension from equivalence to tolerance relations between objects. We briefly show that the heuristic algorithms known from literature to search for templates in their classical indiscernibility-based form, can be easily adapted to the case of tolerance relations.

- Data Analysis, Modelling, and Learning | Pp. 11-19

Reduction Based Symbolic Value Partition

Fan Min; Qihe Liu; Chunlan Fang; Jianzhong Zhang

Theory of Rough Sets provides good foundations for the attribute reduction processes in data mining. For numeric attributes, it is enriched with appropriately designed discretization methods. However, not much has been done for symbolic attributes with large numbers of values. The paper presents a framework for the symbolic value partition problem, which is more general than the attribute reduction, and more complicated than the discretization problems. We demonstrate that such problem can be converted into a series of the attribute reduction phases. We propose an algorithm searching for a (sub)optimal attribute reduct coupled with attribute value domains partitions. Experimental results show that the algorithm can help in computing smaller rule sets with better coverage, comparing to the standard attribute reduction approaches.

- Data Analysis, Modelling, and Learning | Pp. 20-30

Investigative Data Mining for Counterterrorism

Muhammad Akram Shaikh; Jiaxin Wang; Hongbo Liu; Yixu Song

After the tragic events of 9/11, the concern about national security has increased significantly. However, law enforcement agencies, particularly in view of current emphasis on terrorism, increasingly face the challenge of information overload and lack of advanced, automated techniques for the effective analysis of criminal and terrorism activities. Data mining applied in the context of law enforcement and intelligence analysis, called Investigative Data Mining (IDM), holds the promise of alleviating such problems. An important problem targeted by IDM is the identification of terror/crime networks, based on available intelligence and other information. In this paper, we present an understanding to show how IDM works and the importance of this approach in the context of terrorist network investigations and give particular emphasis on how to destabilize them by knowing the information about leaders and subgroups through hierarchical structure.

- Data Analysis, Modelling, and Learning | Pp. 31-41

Data Integration Using Lazy Types

Fernando Berzal; Juan-Carlos Cubero; Nicolás Marín; Maria Amparo Vila

The development of applications that use the different data sources available in organizations require to solve a data integration problem. Most of the methodologies and tools that simplify the task of finding an integrated schema propose conventional object-oriented solutions as the basis for building a global view of the system. As we will see in this work, the use of the conventional object-oriented data model is not as appropriate as we would like when dealing with data variability and we present a novel typing framework, lazy typing, that can be used for obtaining a global schema in the data integration process. This typing framework eases the transparent development of applications that use this integrated schema and reconcile data.

- Data Analysis, Modelling, and Learning | Pp. 42-50

Data Generalization Algorithm for the Extraction of Road Horizontal Alignment Design Elements Using the GPS/INS Data

Sunhee Choi; Junggon Sung

This paper provides the methodologies to extract the road horizontal alignment design elements using the acquisition data from the Global Positioning System (GPS) and Inertial Navigation System (INS). For this study, highly accurate GPS/INS data from the RoSSAV (Road Safety Survey and Analysis Vehicle) were collected, and also extraction algorithm of road horizontal alignment design elements was proposed according to the statistical inference.

- Data Analysis, Modelling, and Learning | Pp. 51-62

Personalized E-Learning Process Using Effective Assessment and Feedback

Cheonshik Kim; Myunghee Jung; Shaikh Muhammad Allayear; Sung Soon Park

The amount and quality of feedback provided to the learner has an impact on the learning process. Personalized feedback is particularly important to the effective delivery of e-learning courses. E-learning delivery methods such as web-based instruction are required to overcome the barriers to traditional-type classroom feedback. Thereby, the feedback for a learner should consist not only of adaptive information about his errors and performance, but also of adaptive hints for the improvement of his solution. Furthermore, the tutoring component is required to individually motivate the learners. In this paper, an adaptive assessment and feedback process model for personalized e-learning is proposed and developed for the purpose of maximizing the effects of learning.

- Data Analysis, Modelling, and Learning | Pp. 63-72

Optimally Pricing European Options with Real Distributions

Chieh-Chung Sheng; Hsiao-Ya Chiu; An-Pin Chen

Most option pricing methods use mathematical distributions to approximate underlying asset behavior. However, it is difficult to approximate the real distribution using pure mathematical distribution approaches. This study first introduces an innovative computational method of pricing European options based on the real distributions of the underlying asset. This computational approach can also be applied to expected value related applications that require real distributions rather than mathematical distributions. The contributions of this study include the following: a) it solves the risk neutral issue related to price options with real distributions, b) it proposes a simple method adjusting the standard deviation according to the practical need to apply short term volatility to real world applications and c) it demonstrates that modern databases are capable of handling large amounts of sample data to provide efficient execution speeds.

- Data Analysis, Modelling, and Learning | Pp. 73-82

Applying Stated Preference Methods to Investigate Effects of Traffic Information on Route Choice

Hye-Jin Cho; Kangsoo Kim

This research is exploring the extent to which providing traffic information on VMS affects drivers’ route choice behaviour. The information include extra delay and charges. Three different charging regimes were tested. Stated preference(SP) surveys were conducted and route choice logit models were estimated. The results show that drivers’ route choice is affected by length of delay and by road user charges on VMS. The fixed charges may be most likely to induce drivers to change their behaviour. Drivers value delay time more highly and they become increasingly sensitive to delay time as it increases.

- Data Analysis, Modelling, and Learning | Pp. 83-92

A Study on Determining the Priorities of ITS Services Using Analytic Hierarchy and Network Processes

Byung Doo Jung; Young-in Kwon; Hyun Kim; Seon Woo Lee

Daegu Metropolitan City is currently in the process of implementing an Intelligent Transportation Systems (ITS) basic plan in order to establish these systems and the foundation of basic services, in addition to setting establishment goals based on the national basic plan of ITS. Some criteria have proven to be very effective at determining the priorities of ITS services, measuring their contribution to solving transportation problems, identifying the services preferred by users, and evaluating ITS systems and related technologies. In this study, the authors prioritize six ITS services using the Analytic Network Process (ANP), which considers mutual dependence between the evaluation items and alternatives. The Analytic Hierarchy Process (AHP), meanwhile, is a one-way process that does not consider the independence of feedback from the services. According to the results of the super decisions ratings, the Regional Traffic Information Center System was chosen to be the top priority project followed by the Urban Arterial Incident Management System and the Bus Information System.

- Data Analysis, Modelling, and Learning | Pp. 93-102

An Introduction of Indicator Variables and Their Application to the Characteristics of Congested Traffic Flow at the Merge Area

Sang-Gu Kim; Youngho Kim; Taewan Kim; YoungTae Son

Research on the merge area has mainly dealt with free flow traffic and research on the congested traffic at the merge area is rare. This study investigates the relationship between mainline traffic and on-ramp traffic at three different segments of the merge area. For this purpose, new indicators based on traffic variables such as flow, speed, and density are used. The results show that a negative relationship exists between mainline and on-ramp flow. It is also found that the speed and the density of the right two lanes in the mainline traffic are significantly affected by the on-ramp flow. Based on the correlation analysis of the indicators, it is confirmed that the right two lanes of the freeway mainline are influenced by the ramp flow. The revealed relationships between mainline and on-ramp traffic may help to analyze the capacity of the downstream freeway segment of the merge area in congested traffic.

- Data Analysis, Modelling, and Learning | Pp. 103-113

Image Resize Application of Novel Stochastic Methods of Function Recovery

Daniel Howard; Joseph Kolibal

A novel family of stochastic methods developed for function recovery tasks is presented and its properties are discussed in some detail. A new image resize facility based on these new methods is applied to an image and this compares favorably in quality to the application to this image of an equivalent facility from a popular commercial graphics package.

- Imaging, Speech, and Complex Data | Pp. 114-127

Automatic Face Analysis System Based on Face Recognition and Facial Physiognomy

Eung-Joo Lee; Ki-Ryong Kwon

An automatic face analysis system is proposed which uses face recognition and facial physiognomy. It first detects human’s face, extracts its features, and classifies the shape of facial features. It will analyze the person’s facial physiognomy and then automatically make an avatar drawing using the facial features. The face analysis method of the proposed algorithm can recognize face at real-time and analyze facial physiognomy which is composed of inherent physiological characteristics of humans, orientalism, and fortunes with regard to human’s life. The proposed algorithm can draw the person’s avatar automatically based on face recognition. We conform that the proposed algorithm could contribute to the scientific and quantitative on-line face analysis fields as well as the biometrics.

- Imaging, Speech, and Complex Data | Pp. 128-138

Moving Cast Shadow Elimination Algorithm Using Principal Component Analysis in Vehicle Surveillance Video

Wooksun Shin; Jongseok Um; Doo Heon Song; Changhoon Lee

Moving cast shadows on object distort figures which causes serious detection deficiency and analysis problems in ITS related applications. Thus, shadow removal plays an important role for robust object extraction from surveillance videos. In this paper, we propose an algorithm to eliminate moving cast shadow that uses features of color information about foreground and background figures. The significant information among the features of shadow, background and object is extracted by PCA transformation and tilting coordinates system. By appropriate analyses of the information, we found distributive characteristics of colors from the tilted PCA space. With this new color space, we can detect moving cast shadow and remove them effectively.

- Imaging, Speech, and Complex Data | Pp. 139-148

Automatic Marker-Driven Three Dimensional Watershed Transform for Tumor Volume Measurement

Yong-su Chae; Desok Kim

Molecular imaging can detect abnormal functions of living tissue. Functional abnormality in gene expression or metabolism can be represented as altered volume or probe intensity. Accurate measurement of volume and probe intensity in tissue mainly relies on image segmentation techniques. Thus, segmentation is a critical technique in quantitative analysis. We developed an automatic object marker-driven three dimensional(3D) watershed transform for quantitative analysis of functional images. To reduce the discretization error in volume measurement less than 5%, the size criteria for digital spheres were investigated to provide the minimum volume. When applied to SPECT images, our segmentation technique produced 89% or higher accuracy in the volume and intensity of tumors and also showed high correlation with the ground truth segmentation (> 0.93). The developed 3D method did not require interactive object marking and offered higher accuracy than a 2D watershed approach. Furthermore, it computed faster than the segmentation technique based on the marker-driven gradient modification.

- Imaging, Speech, and Complex Data | Pp. 149-158

A Study on the Medical Image Transmission Service Based on IEEE 802.15.4a

Yang-Sun Lee; Jae-Min Kwak; Sung-Eon Cho; Ji-Woong Kim; Heau-Jo Kang

In this paper, the transmission service for medical image is proposed via IEEE 802.15.4a on WPAN environment. Also, transmission and receiving performance of medical image using TH UWB-IR system is evaluated on indoor multi-path fading environment. On the results, the proposed scheme can solve the problem of interference from the medical equipment in same frequency band, and minimize the loss due to the indoor multi-path fading environment. Therefore, the transmission with low power usage is possible.

- Imaging, Speech, and Complex Data | Pp. 159-167

Detecting Image Based Spam Email

Wanli Ma; Dat Tran; Dharmendra Sharma

Image based spam email can easily circumvent widely used text based spam email filters. More and more spammers are adapting the technology. Being able to detect the nature of email from its image content is urgently needed. We propose to use OCR (optical character recognition) technology to extract the embedded text from the images and then assess the nature of the email by the extracted text using the same text based engine. This approach avoids maintaining an extra image based detection engine and also takes the benefit of the strong and reasonably mature text based engine. The success of this approach relies on the accuracy of the OCR. However, regardless of how good an OCR is, misrecognition is unavoidable. Therefore, a Markov model which has the ability to tolerate misspells is also proposed. The solution proposed in this paper can be integrated smoothly into existing spam email filters.

- Imaging, Speech, and Complex Data | Pp. 168-177

Efficient Fixed Codebook Search Method for ACELP Speech Codecs

Eung-Don Lee; Jae-Min Ahn

There are several sub-optimal search techniques for fast algebraic codebook search of ACELP speech codecs. Focused search method, depth-first tree search method and pulse replacement methods are used to reduce computational complexity of algebraic codebook search. In previous pulse replacement methods, the computational load is increased as the pulse replacement procedure is repeated. In this paper, we propose a fast algebraic codebook search method based on iteration-free pulse replacement. The proposed method is composed of two stages. At the first stage, an initial codevector is determined by the backward filtered target vector or the pulse-position likelihood-estimate vector. At the second stage, after computing pulse contributions for every track the pulse replacement is performed to maximize the search criterion over all combination replacing the pulses of the initial codevector with the most important pulses for every track. The performance of the proposed algebraic codebook search method is measured in terms of the segmental signal to noise ratio (SNRseg) and PESQ (Perceptual Evaluation of Speech Quality) using various speech data. Experimental results show that the proposed method is very efficient in computational complexity and speech quality comparing to previous pulse replacement methods.

- Imaging, Speech, and Complex Data | Pp. 178-187

Conventional Beamformer Using Post-filter for Speech Enhancement

Soojeong Lee; Kiho Choi; Soonhyob Kim

This paper presents a combined handsfree speech enhancement method based on a spatialpost-filter. The scheme uses a linear microphone array to capture a speech signal that has been corrupted by babble noise, car noise, and interference signals. Simulation results for real environment show that the proposed structure achieves a maximum interference suppression of 12 dB, an improvement of 6 dB over the delay and sum beamformer. Furthermore, the system is robust in the presence of distortion as opposed to the generalized sidelobe canceller. The subjective evaluation has shown that the combined system of delay and sum with the minimum mean square error estimator using a noncausal signal to noise ratio (SNR) estimator obtained 3.8 points on a fivepoint.

- Imaging, Speech, and Complex Data | Pp. 188-197

Bandwidth Extension of a Narrowband Speech Coder for Music Delivery over IP

Young Han Lee; Hong Kook Kim; Mi Suk Lee; Do Young Kim

In this paper, we propose a bandwidth extension (BWE) algorithm of a narrowband speech coder for music delivery services over IP networks. The proposed BWE algorithm is based on an embedded structure of using a baseline coder followed by an enhancement layer. To minimize the bit-rate increase by the enhancement layer, the proposed algorithm shares spectral envelope and excitation parameters between the baseline coder and the enhancement layer. In this paper, we choose the iLBC as the baseline coder and mel-frequency cepstral coefficients (MFCCs) are used to reconstruct higher frequency components at the enhancement layer. By doing this, the bit-rate of the proposed BWE coder is 15.45 kbit/s which is just 0.25 kbit/s higher than the iLBC. We compare the quality of the proposed BWE coder with that of the iLBC, and it is shown from an informal listening test that the proposed BWE coder provides significantly better quality than the iLBC for all four different kinds of music genres such as pop, classical, jazz and rock.

- Imaging, Speech, and Complex Data | Pp. 198-208

A User-Oriented GIS Search Service Using Ontology in Location-Based Services

Hyunsuk Hwang; Seonghyun Shin; Changsoo Kim

Geographical Information Systems (GIS) technology plays an increasingly important role in Location-Based Services (LBS), which include applications such as car navigation, tour guide information, route-guide information, and tracking systems. Most GIS applications focus on showing the stored information on a map, not providing user-oriented map services to register user’s preferred information. We propose an ontology-based approach to register and to search personal information on maps. We also implement a GIS search prototype considering user preferences using favorite food information and having a connection function to Web sites on the map using our digital map format. Our contribution is to provide a personalized service by connecting LBS/GIS services and ontology technology.

- Imaging, Speech, and Complex Data | Pp. 209-218

A Filtered Retrieval Technique for Structural Information

Young-Ho Park; Yong-Ik Yoon; Jong-Woo Lee

We present a filtered retrieval technique for structural information on internet-scale knowledge such as large-scale XML data in the Web. The technique evaluates XML standard queries on heterogeneous XML documents using information retrieval technique based on the relational tables in relational database management systems. The XML standard queries, XPath queries, in their general form are partial match queries, and these queries are particularly useful for searching documents of heterogeneous schemas. Thus, our technique is geared for partial match queries expressed as the queries. This indexes the elements in label paths, which are sequences of node labels, like keywords in texts, and finds the label paths matching a given query.

- Imaging, Speech, and Complex Data | Pp. 219-228

An Analysis of a Lymphoma/Leukaemia Dataset Using Rough Sets and Neural Networks

Kenneth Revett; Marcin Szczuka

In this paper, we describe a rough sets approach to classification and attribute extraction of a lymphoma cancer dataset. We verify the classification accuracy of the results obtained from rough sets with a two artificial neural network based classifiers (ANNs). Our primary goal was to produce a classifier and a set of rules that could be used in a predictive manner. The dataset consisted of a number of relevant clinical variables obtained from patients that were suspected of having some form of blood based cancer (lymphoma or leukaemia). Of the 18 attributes that were collected for this patient cohort, seven were useful with respect to outcome prediction. In addition, this study was able to predict with a high degree of accuracy whether or not the disease would undergo metastases.

- Applications of Artificial Intelligence | Pp. 229-239

A Frequency Adaptive Packet Wavelet Coder for Still Images Using CNN

N. Venkateswaran; J. Vignesh; S. Santhosh Kumar; S. Rahul; M. Bharadwaj

We present the packet wavelet coder implemented with Cellular Neural Network architecture as an example of the applications of cellular neural networks. This paper also demonstrates how the cellular neural universal machine (CNNUM) architecture can be extended to image compression. The packet wavelet coder performs the operation of image compression, aided by CNN architecture. It uses the highly parallel nature of the CNN structure and its speed outperforms traditional digital computers. In packet wavelet coder, an image signal can be analyzed by passing it through an analysis filter banks followed by a decimation process, according to the rules of packet wavelets. The Simulation results indicate that the quality of the reconstructed image is improvised by using packet wavelet coding scheme.

- Applications of Artificial Intelligence | Pp. 240-248

Reduced RBF Centers Based Multi-user Detection in DS-CDMA Systems

Jungsik Lee; Ravi Sankar; Jaejeong Hwang

The major goal of this paper is to develop a practically implemental radial basis function neural network based multi-user detector for direct sequence code division in multiple access systems. This work is expected to provide an efficient solution by quickly setting up the proper number of radial basis function centers and their locations required in training. The basic idea in this research is to select all the possible radial basis function centers by using supervised -means clustering technique, select the only centers which locate near seemingly decision boundary, and reduce them further by grouping some of the centers adjacent to each other. Therefore, it reduces the computational burden for finding the proper number of radial basis function centers and their locations in the existing radial basis function based multi-user detector, and ultimately, make its implementation practical.

- Applications of Artificial Intelligence | Pp. 249-257

Approximate Life Cycle Assessment of Product Concepts Using a Hybrid Genetic Algorithm and Neural Network Approach

Kwang-Kyu Seo; Won-Ki Kim

Environmental impact assessment of products has been a key area of research and development for sustainable product development. Many companies copy these trends and they consider environmental criteria into the product design process. Life Cycle Assessment (LCA) is used to support the decision-making for product design and the best alternative can be selected by its estimated environmental impacts and benefits. The need for analytical LCA has resulted in the development of approximate LCA. This paper presents an optimization strategy for approximate LCA using a hybrid approach which incorporate genetic algorithms (GAs) and neural networks (NNs). In this study, GAs are employed to select feature subsets to eliminate irrelevant factors and determine the number of hidden nodes and processing elements. In addition, GAs will optimize the connection weights between layers of NN simultaneously. Experimental results show that a hybrid GA and NN approach outperforms the conventional backpropagation neural network and verify the effectiveness of the proposed approach.

- Applications of Artificial Intelligence | Pp. 258-268

A Solution for Bi-level Network Design Problem Through Nash Genetic Algorithm

Jong Ryul Kim; Jung Bok Jo; Hwang Kyu Yang

This paper presents a Nash genetic algorithm (Nash GA) as a solution for a network design problem, formulated as a bi-level programming model and designs a backbone topology in a hierarchical Link-State (LS) routing domain. Given that the sound backbone topology structure has a great impact on the overall routing performance in a hierarchical LS domain, the importance of this research is evident. The proposed decision model will find an optimal configuration that consists of backbone router for Backbone Provider (BP), router for Internet Service Provider (ISP), and connection link properly meeting two-pronged engineering goals: i.e., average message delay and connection costs. It is also presumed that there are decision makers for BP and the decision makers for ISP join in the decision making process in order to optimize the own objective function. The experiment results clearly indicates that it is essential to the effective operations of hierarchical LS routing domain to consider not only the engineering aspects but also specific benefits from systematical layout of backbone network, which presents the validity of the decision model and Nash GA.

- Applications of Artificial Intelligence | Pp. 269-280

An Alternative Measure of Public Transport Accessibility Based on Space Syntax

Chulmin Jun; Jay Hyoun Kwon; Yunsoo Choi; Impyeong Lee

The local governments of major cities in Korea are giving focus on public transportation to reduce congestion and improve accessibility in city areas. In this regards, the proper measurement of accessibility is now a key policy requirement for reorganizing the public transport network. However, Public transport routing problems are considered to be highly complicated since a multi-mode travel generates different combinations of accessibility. While most of the previous research efforts on measuring transport accessibility are found at zone-levels, an alternative approach at a finer scale such as bus links and stops is presented in this study. We propose a method to compute the optimal route choice of origin-destination pairs and measure the accessibility of the chosen mode combination based on topological configuration. The genetic algorithm is used for the computation of the journey paths, whereas the space syntax theory is used for the accessibility. The resulting accessibilities of bus stops are calibrated by O-D survey data and the proposed process is tested on a CBD of Seoul using the city GIS network data.

- Applications of Artificial Intelligence | Pp. 281-291

Adaptive Routing Algorithm Using Evolution Program for Multiple Shortest Paths in DRGS

Sung-Soo Kim; Seung B. Ahn

There are several search algorithms for the shortest path problem: the Dijkstra algorithm and Bellman-Ford algorithm, to name a few. These algorithms are not effective for dynamic traffic network involving rapidly changing travel time. The evolution program is useful for practical purposes to obtain approximate solutions for dynamic route guidance systems (DRGS). The objective of this paper is to propose an adaptive routing algorithm using evolution program (ARAEP) that is to find the multiple shortest paths within limited time when the complexity of traffic network including turn-restrictions, U-turns, and P-turns exceeds a predefined threshold.

- Applications of Artificial Intelligence | Pp. 292-301

Particle Swarm Optimization for a Multi-UCAV Cooperative Task Scheduling

Xiaohua Huo; Lincheng Shen; Tao Long

Task scheduling is one of the core steps to effectively exploit the capabilities of cooperative control of multiple uninhabited combat aerial vehicles(UCAVs) team. The main function of multi-UCAV cooperative task scheduling is to allocate tasks which should be implemented by vehicles, and arrange the sequence of these tasks to be carried out for each vehicle simultaneously, while optimizing the team objective and satisfying various constrains of vehicles and tasks. By analyzing the characters of tasks and UCAVs, we presented a general mathematical model based on a combinatorial optimization. By defining a suitable particle structure, the Particle Swarm Optimization (PSO) algorithm was applied to solve this problem. Adaptive weight values and stochastic turbulence strategies were added to the algorithm. Simulation results indicate that the PSO algorithm proposed in this paper is a feasible and efficient approach for task scheduling in multi-UCAV cooperative control.

- Applications of Artificial Intelligence | Pp. 302-311

Expert System Using Fuzzy Petri Nets in Computer Forensics

Hyun-Uk Hwang; Min-Soo Kim; Bong-Nam Noh

In the past, computer forensics was only used by means of investigation. However, nowadays, due to the sharp increase of awareness of computer security, computer forensics becomes very significant even to the nonprofessionals, and it needs inference as well as the integrity and reliability of the procedure. In this paper, we describe the inference rules using Fuzzy Petri Nets and adapt the collected data in a compromised system to a proposition for inference of the intrusion information. The inferred results are expressed as formalized 5W1H format. The COMFEX(COMputer Forensic EXpert system) is inferable, even if the data is damaged in certain section, and the inference function of uncertainty is improved. This is useful to a system administrator who has weak analyzing ability of hacking, and it has improved capacity of managing the system security.

- Applications of Artificial Intelligence | Pp. 312-322

MMORPG Map Evaluation Using Pedestrian Agents

Christian Anthony L. Go; Tristan Basa; Won-Hyung Lee

Massive Multiplayer Online Role-Playing Games (MMO- RPG) increasingly become places of social engagement, by providing spaces for social interaction and relationship beyond home and workplace. The center of this is the virtual environment, in which players interact. Today’s savvy players are demanding progressive, more playable and navigable game environments. Traditional methods of the game map evaluation, though reliable, do not offer a quantitative measure of players’ discomfort and efficiency. This paper introduces a complementary method of the MMORPG map evaluation by utilizing pedestrian agents. The agents employ calculable measures of walking efficiency and discomfort, providing objective criteria, against which the game maps are evaluated. Thus, they promote social interaction by improving the space wherein the players interact.

- Applications of Artificial Intelligence | Pp. 323-332

The Analysis of Game Playing Experiences: Focusing on Massively Multiplayer Online Role-Playing Game

Seungkeun Song; Joohyeon Lee; Jun Jo

The purpose of this study is to (1) develop an analytic framework to systematically code the players’ cognitive process during Massively Multiplayer Online Role-Playing Game (MMORPG) gameplay, and (2) to empirically explore the players’ cognitive process. To construct the analytical framework of MMORPG gameplay, previous studies regarding gameplay and problem solving theory are reviewed. The specific gameplay actions and contents are derived by using a concurrent protocol analysis method. Consequently, gameplay actions are categorized into kinematics, perception, function, representation, methodology, and simulation. A new framework suitable for MMORPG gameplay is built. In order to study the players’ cognitive process, the empirical experiment is executed during MMORPG gameplay. As a result of this study, we find a new problem space in the methodological scheme of gameplay. This study concludes with a number of key implications for game design in order to improve the quality of future gaming products.

- Applications of Artificial Intelligence | Pp. 333-343

How to Overcome Main Obstacles to Building a Virtual Telematics Center

Bong Gyou Lee

This paper describes the limiting factors for building a virtual Telematics center which integrates ITS (Intelligent Transportation Systems) information collected by the system of each of the three government agencies. It also provides some details into how some of the obstacles and barriers can be solved such as data standardization, system mechanisms and regulations. There are very few papers and case studies regarding real problems and solutions for integrating systems of different organizations in general, and Telematics, in particular. The processes and outcomes of implementing systems in this study can be useful to develop other ITS and Telematics systems.

- Hybrid, Smart, and Ubiquitous Systems | Pp. 344-351

Real-Time Travel Time Estimation Using Automatic Vehicle Identification Data in Hong Kong

Mei Lam Tam; William H. K. Lam

This paper proposes a real-time traveler information system (RTIS) for estimating current travel times using automatic vehicle identification (AVI) data in Hong Kong. The current travel times, in RTIS, are estimated by real-time AVI data, the off-line travel time estimates and the related variance-covariance relationships between road links. The real-time AVI data adopted for RTIS are Autotoll tag data in Hong Kong; whereas the off-line link travel time estimates and their variance-covariance matrices are obtained from a traffic flow simulator. On the basis of integration of these real-time and off-line traffic data, the current traffic conditions on Hong Kong major roads can be estimated at five-minute intervals. A case study is carried out in Kowloon Central urban area to collect observed data for validation of the results of the proposed RTIS.

- Hybrid, Smart, and Ubiquitous Systems | Pp. 352-361

A Context-Aware Elevator Scheduling System for Smart Apartment Buildings

Ohhoon Kwon; Hyokyung Bahn; Kern Koh

Ubiquitous computing technologies are becoming increasingly a part of our daily lives. For example, in the ubiquitous home environments, plenty of context information can be obtained from various home sensors, and this information can be exploited for smart home activities. This paper presents a new elevator scheduling system for smart apartment buildings that exploits the ubiquitous sensor technologies. In the proposed elevator scheduling system, floor sensors are located at each floor of the apartment building and detect the candidate elevator passengers’ behavior before they come to the elevator door and push the elevator call button. The detected information is then delivered to the elevator scheduling system through the building network and the elevator scheduling system utilizes this information in the efficient control of the elevator. Through extensive simulations with various passengers’ traffic conditions, we show that the proposed system performs better than the conventional elevator scheduling system in terms of the passengers’ average waiting time, the maximum waiting time, and the energy consumption of the elevator significantly.

- Hybrid, Smart, and Ubiquitous Systems | Pp. 362-372

A MOM-Based Home Automation Platform

Chun-Yuan Chen; Chi-Huang Chiu; Shyan-Ming Yuan

While there have been many home networking technologies such as UPnP and INSTEON, appliances supporting different home networking technologies cannot collaborate to finish Home Automation (HA). Although many studies of interoperability among home networking technologies have been done, researches on further HA in heterogeneous environments are still lacking. This paper proposes the MOM-based Home Automation Platform (MHAP), which accomplishes event-driven HA in incompatible home networks. MHAP is independent of any home networking technology and integrates home networking technologies in the home gateway. For users, MHAP provides the easy-to-use and standardized way to configure complex HA scenarios by rules. Through introducing Message Oriented Middleware (MOM) and Open Service Gateway Initiative (OSGi), MHAP offers reliable automatic operations, fault tolerant and reconfigurable HA, high extensibility and large scalable collaboration among appliances, other MHAP gateways and Internet services.

- Hybrid, Smart, and Ubiquitous Systems | Pp. 373-384

An Error Sharing Agent for Multimedia Collaboration Environment Running on Pervasive Networks

Eung Nam Ko

This paper presents the design of an error sharing agent for multimedia collaboration environment which is running on RCSM. RCSM means Reconfigurable Context-Sensitive Middleware. RCSM provides an object-based framework for supporting context-sensitive applications. It has other services in optional components. A good example of other services in RCSM is a distance education system for multimedia collaboration environment. We propose an adaptive error hooking agent based on a hybrid software architecture CARV(Centralized Abstraction and Replicated View). This system can be automatically enforced according to different situations such as wired or wireless network environment.

- Hybrid, Smart, and Ubiquitous Systems | Pp. 385-394

A Hybrid Intelligent Multimedia Service Framework in Next Generation Home Network Environment

Jong Hyuk Park; Jungsuk Song; Byoung-Soo Koh; Deok-Gyu Lee; Byoung-Ha Park

In Next Generation Home network Environment (NGHE), multimedia service will be a key concept of advanced intelligent and secure services which are different from the existing ones. In this paper, we propose a Hybrid Intelligent Multimedia Service Framework (HIMSF) which is mixed with application technologies like intelligent home Infrastructure or multimedia protection management through the ubiquitous sensor network based technology to provide a proper multimedia service suitable for NGHE. The proposed framework provides an inter-operability among heterogeneous equipments regarding home network appliances like wireless devices, electronic appliances, PC. In addition, it provides adaptive application services.

- Hybrid, Smart, and Ubiquitous Systems | Pp. 395-403

Integration of Artificial Market Simulation and Text Mining for Market Analysis

Kiyoshi Izumi; Hiroki Matsui; Yutaka Matsuo

It is important to understand and to provide a rationale for the actions of users in financial markets. Simulations of artificial financial markets are one means by which to address these needs, and this paper describes how to integrate the technique of text mining with a simulation of an artificial financial market to enhance the value and usefulness of the simulation. The procedure that is proposed consists of extracting the economic trends from the text data that is circulating in the real world and to input these economic trends into the market simulation. We show how this was experimentally tested as a decision support system for an exchange rate policy and how it suggested that the applied combination of interest rate and intervention operations was effective for stabilization of the yen-dollar rate in 1994 and 1995.

- Hybrid, Smart, and Ubiquitous Systems | Pp. 404-413

Agent-Based Intelligent Decision Support for the Home Healthcare Environment

Louie Cervantes; Yong-Seok Lee; Hyunho Yang; Sung-hyun Ko; Jaewan Lee

This paper brings together the multi-agent platform and artificial neural network to create an intelligent decision support system for a group of medical specialists collaborating in the pervasive management of healthcare for chronic patients. Artificial intelligence is employed to support the management of chronic illness through the early identification of adverse trends in the patient’s physiological data. A framework based on software agents that proxy for participants in a home healthcare environment is presented. The proposed approach enables the agent-based home healthcare system to identify the emergent chronic conditions from the patterns of symptoms and allows the appropriate remediation to be initiated and managed transparently.

- Hybrid, Smart, and Ubiquitous Systems | Pp. 414-424

An Aware-Environment Enhanced Group Home: AwareRium

Hideaki Kanai; Toyohisa Nakada; Goushi Tsuruma; Susumu Kunifuji

We have constructed “AwareRium”, an enhanced group home with ubiquitous technology to establish person-centered care. The group home is a facility that provides care for Alzheimer’s and dementia patients. The group home is effective in curbing the progress of Alzheimer’s dementia. A small number of elderly persons with no relations in need of care, support, or supervision, such as Alzheimer’s and dementia patients, can live together in the group home. In this paper, we describe the design concept of AwareRium and the sensing and projection devices installed therein. We present two support systems for position awareness using these devices in AwareRium: a system for finding lost objects and a system for identifying and noticing dangers in order to prevent dangers in the group home.

- Hybrid, Smart, and Ubiquitous Systems | Pp. 425-436

The Situation Dependent Application Areas of EPC Sensor Network in u-Healthcare

Yoonmin Hwang; Garam Park; Eunji Ahn; Jaejeung Rho; Jonwoo Sung; Daeyoung Kim

Electronic product code (EPC) sensor network is a collection of objects for sensing data. It is crucial to ubiquitous society. It can provide an application service based on situation dependency with its properties. The situation dependency is an emerging concept which can collect location-based and personalized information. With the situation dependency, many industries can serve ubiquitous service for independent users. u-Healthcare is one of ubiquitous service to provide seamless medical treatment. The concept of situation dependency is applied in u-Healthcare with EPC sensor network technology. Due to specialized four properties of EPC sensor network which are driven from this paper, the situation dependency is well-established in u-Healthcare service. In this paper, we defined value and architecture of u-Healthcare service and we analyzed application areas of u-Healthcare.

- Hybrid, Smart, and Ubiquitous Systems | Pp. 437-446

Ubiquitous Healthcare System Using Context Information Based on the DOGF

Chang-Sun Shin; Dong-In Ahn; Dong-Seok Kim; Su-Chong Joo

This paper proposed the Ubiquitous Healthcare System using context information for the personalized healthcare services in a home network environment. The context information is generated by location, health, and home environment information collected from sensors/devices equipped in home. This system is designed on the Distributed Object Group Framework (DOGF) supporting the functions which manage context information, applications and devices as one or more logical units in healthcare home environment. Especially, the system provides the continuous healthcare multimedia service by generating the context information based on resident’s location through the Mobile Proxy and the Context Provider as components of the DOGF. For verifying the execution of our system, we implemented the seamless multimedia service, the prescription/advice service and the schedule notification/alarm service according to a healthcare scenario in home. Finally, we showed the execution results of healthcare home services by using service devices existed in the residential space.

- Hybrid, Smart, and Ubiquitous Systems | Pp. 447-457

Load Balancing Using Dynamic Replication Scheme for the Distributed Object Group

Romeo Mark A. Mateo; Marley Lee; Jaewan Lee

CORBA is the most widely used middleware for implementing distributed application. Currently, object implementations facilitate object group model to organize the object services. In addition to the complexity of designing the object groups, researchers also seek to improve the quality of service (QoS) by various means such as implementing load balancing to the system. This paper deals with the proposed load balancing service of distributed object groups. The proposed load balancing service uses the dynamic replication scheme which is mechanized by flow balance assumption (FBA) that derives from the arrival and service rate to execute request forwarding to new objects. The proposed on-demand replication scheme adjusts the number of replicated objects based on the arrival rate to minimize the waiting time of clients. It consists of procedures such as intercepting the request and executing on-demand activation of objects. The result of the simulation shows the improvement of the total mean client request completion time of the system as compared to other load balancing schemes.

- Hardware and Software Engineering | Pp. 458-468

Design and Implementation of a Performance Analysis and Visualization Toolkit for Cluster Environments

Tien-Hsiung Weng; Hsiao-Hsi Wang; Tsung-Ying Wu; Ching-Hsien Hsu; Kuan-Ching Li

The low cost and wide availability of PC-based clusters have made them excellent alternatives to supercomputing. However, while Network of Workstations are readily available, there is an increasing need for performance tools that support these computing platforms in order to achieve even higher performance. Strategies that may be considered toward such performance achievement we may list are: performance data analysis, algorithm design, parallel program restructuring, among others. Introduced in this paper is a toolkit that generates performance data and graphical charts of pure MPI, pure OpenMP, as well as hybrid MPI/OpenMP parallel applications, reflecting to its sequence of execution over time and cache behavior, with the use of DP*Graph representation, a parallel version of timing graph. That is, parallel applications have their execution sequence in a cluster system platform shown through graphical charts composed by sequential codes, parallel threads, dependencies and communication structures, symbols defined in DP*Graph. It is discussed the implementation of this toolkit, as also some of its features, together with experimental use of the toolkit on parallel applications such as matrix multiplication (parallel implementation using MPI) and SPICE3 (parallel implementation using OpenMP).

- Hardware and Software Engineering | Pp. 469-479

Enterprise Application Framework for Constructing Secure RFID Application

Hyundong Lee; Kiyeal Lee; Mokdong Chung

In the ubiquitous environment, anyone could easilyaccess all shared informations which means it also has many serious drawbacks, such as security problems. Therefore the ubiquitous environment should provide a security service. This paper suggests an Enterprise Application Framework(EAF) which includes a security module as well as a business process module for constructing secure RFID application. The security module includes user authentication mechanism, key sharing mechanism, and authorization mechanism. Thus, this framework is expected to provide more secure management in the ubiquitous environments such as RFID applications.

- Hardware and Software Engineering | Pp. 480-489

A GDB-Based Real-Time Tracing Tool for Remote Debugging of SoC Programs

Myeong-Chul Park; Young-Joo Kim; In-Geol Chun; Seok-Wun Ha; Yong-Kee Jun

Since embedded systems based on System-on-a-Chip(SoC) have limited resources, debugging programs in such systems requires a remote debugging system that has enough resources. However, existing JTAG based remote debugging system that uses GDB in Linux environment does not provide tracing function, so it is hard to monitor the executions of SoC program in real time. This paper adds a tracing facility to existing GDB remote debugging system to provide a real time monitoring tool. To demonstrate a real time tracing of synthetic program, Intel a Xscale PXA series processor based target system is used.

- Hardware and Software Engineering | Pp. 490-499

A Novel Buffer Cache Scheme Using Java Card Object with High Locality for Efficient Java Card Applications

Won-Ho Choi; Ha-Yong Jeon; Rhys Rosholt; Gwang Jung; Min-Soo Jung

Java Card technology enables smart cards and other devices with very limited memory to run small applications. It provides users with a secure and interoperable execution platform that can store and update multiple applications on a single device. However, a major difficulty with Java Card is its low execution speed caused by hardware limitations. In this paper, we propose a novel scheme about how to improve the execution speed of Java Card. The key idea of our approach is a buffer cache scheme that uses RAM instead of EEPROM to improve the execution speed of Java Card. The proposed scheme reduces I/O count, especially EEPROM writing. Our scheme is based on the high locality of Java Card objects and the use of RAM that is several magnitude faster than EEPROM.

- Hardware and Software Engineering | Pp. 500-510

Design and Implementation of the Decompiler for Virtual Machine Code of the C++ Compiler in the Ubiquitous Game Platform

YangSun Lee; YoungKeun Kim; HyeokJu Kwon

The ubiquitous game platform implemented by our team is composed of a C++ compiler, a java translator, and a virtual machine. The EVM (Embedded Virtual Machine) is a stack-based solution that supports object-oriented languages such as C++ and java. It uses the SIL (Standard Intermediate Language) as an intermediate language, which consists of an operation code set for procedural and object-oriented languages. The existing C++ compilers are used to execute programs after translating them into a target machine code. The downside of this method is its low practicality, along with its platform-dependency. To resolve this matter, we developed a C++ compiler that generates virtual machine codes based on platform-independent stacks that are not target machine codes. This paper presents a decompiler system that converts a C++ compiler generated intermediate language, namely SIL, to a representation of a C++ program. This method optimizes the simulation needed for the generation of exacted SIL code, and a solution that can verify the SIL code generation through a C++ program represented in the decompiler. Furthermore, the ease of extracting the meaning of a program, as opposed to assembly-structured SIL codes, allows much more convenience in changing the software structure and correcting it to improve performance.

- Hardware and Software Engineering | Pp. 511-521

Mobile Pharmacology

Patrik Eklund; Johan Karlsson; Annica Näslund

In mobile usage scenarios, patient care involving point of care considerations build upon increasingly complex information and information structures. Furthermore, communication of information must be enabled regardless of space and time. Decision support and guidelines are expected to communicate with other subsystems, such as those provided by information sources and hardware devices. As also these subsystems may build upon intelligence and involve their own usage scenarios, this implies further complications also the knowledge representation and software engineering tasks. In these developments, public health problems provide case studies with potentially rather huge impacts. Examples are provided e.g. by guidelines involving pharmacological treatment. Knowledge and reasoning need to interact with information management, and often involves utility of various devices. Well organized databases for pharmacological information are necessary for successful engineering of mobile extensions in these case studies. The public is now also one of the driving forces in these developments. As electronic prescriptions and generic substitutes are appreciated by the public, we experience how knowledge in its various forms provide success stories in this field.

- Hardware and Software Engineering | Pp. 522-533

Wireless Control System for Pet Dogs in a Residential Environment

Ji-Won Jung; Dong-Sung Kim

This paper concerns a wireless control system (WCS) for pet dogs using wireless sensor networks (WSNs) in a residential environment. The developed WCS is composed of a central control system, a wireless auto-feeder, a small-sized guidance robot, and wireless sensing devices. The developed system uses luminance, temperature, and sound data from a pet dog and the surrounding environment. The presented design method provides an efficient way to control and monitor the pet dog using WSNs. The implemented system can be used as a design framework of portable devices for pet dog control within a residential network.

- Hardware and Software Engineering | Pp. 534-545

Intelligent Embedded Real-Time Software Architecture for Dynamic Skill Selection and Identification in Multi-shaped Robots

Laxmisha Rai; Soon Ju Kang

This paper presents an intelligent embedded, modular software and hardware architecture for multi-shaped robots using real-time dynamic skill identification and selection. It is a layered architecture with reusable and reconfigurable modules, which can embed in an expert system as both hardware and software modules and demonstrated with snake robot and physically reconfigured four-legged robot as examples. The intelligent dynamic selection and synchronization of selected behaviors enable the mobile robot to perform many tasks in complex situations. The architecture proposed is applicable to multi-shaped robots, for dynamic selection of behaviors during reconfiguration, where the hardware and software modules can be reused during reconfiguration. Related videos of these robots can be viewed at:

- Hardware and Software Engineering | Pp. 546-556

The Accurate Performance Evaluation of Time Hopping UWB Systems with Pulse Based Polarity

Jang-Woo Park; Kyung-Ryoung Cho; Nam-Hong Jo; Sung-Eon Cho

The bit rate performance of the time hopping impulse radio UWB system with the pulse based polarity is analyzed. It is well known that the pulse polarity helps reduce the spectral spike appearing in the conventional impulse radio system. This paper provides the method for accurately modeling the multiple access interference(MAI) in the system with the pulse polarity. The characteristic function is used to consider the MAI. We also show the MAI can be simplified as Gaussian random variable when the number of pulses representing an information symbol or the pulse rate becomes large. It is obtained directly from approximating the Characteristic Function of the MAI in case of the large number of pulses. Some results have been shown to prove validity for our method. The results also show with the total processing gain fixed, increasing the pulse rates proves the system performance. But the system without the pulse polarity does not.

- Networking and Telecommunications | Pp. 557-565

Improvement of Adaptive Modulation System with Optimal Turbo Coded V-BLAST Technique

Kyunghwan Lee; Kwangwook Choi; Sangjin Ryoo; Kyoungwon Lee; Mingoo Kang; Intae Hwang; Taejin Jung; Daejin Kim; Cheolsung Kim

In this paper, we propose and analyze the Adaptive Modulation System with optimal Turbo Coded V-BLAST (Vertical-Bell-lab Layered Space-Time) technique that adopts the extrinsic information from MAP (Maximum A Posteriori) Decoder with Iterative Decoding as a priori probability in two decoding procedures of a V-BLAST scheme; the ordering and the slicing. Also, comparing with the Adaptive Modulation System using conventional Turbo Coded V-BLAST technique that is simply combined a V-BLAST scheme with a Turbo Coding scheme, we observe how much throughput performance can be improved. As a result of a simulation, it has been proved that the proposed system achieves a higher throughput performance than the conventional system in the whole SNR (Signal to Noise Ratio) range. Specifically, the result shows that the maximum throughput improvement is about 350 kbps.

- Networking and Telecommunications | Pp. 566-575

Header Compression of RTP/UDP/IP Packets for Real Time High-Speed IP Networks

Kyung-shin Kim; Moon-sik Kang; In-tae Ryoo

In this paper, a new header compression scheme considering BCB (Basic Compression Bits) or NCB (Negotiation Compression Bits). The header compression scheme can be used for reducing the header size by eliminated repeated fields in the packet header. Here, the efficiency of the compression of the dynamic field in RTP/UDP/IP packets is very important in real-time high-speed IP networks. Our new compression method with SN and TS fields can be applicable to IPHC (Internet Protocol Header Compression), ROHC (Robust Header Compression Protocol), and other header compression schemes. The performance of the proposed scheme is discussed via simulation results.

- Networking and Telecommunications | Pp. 576-585

Repetition Coding Aided Time-Domain Cancellation for Inter-Carrier Interference Reduction in OFDM Systems

Jeong-Wook Seo; Jae-Min Kwak; Won-Gi Jeon; Jong-Ho Paik; Sung-Eon Cho; Dong-Ku Kim

In this paper, an enhanced time-domain cancellation method is proposed for inter-carrier interference (ICI) reduction in OFDM systems. The conventional time-domain cancellation neglects the effect of channel variation in cyclic prefix during the time-domain cancellation and does not work well in deep fades. In order to supplement the conventional method, the simple repetition (de-)coding and the modulation order increasing are employed in the time-domain cancellation. The repetition coding provides reliable symbols in the regeneration operation, and the modulation order increasing maintains or increases the spectral efficiency. Simulation results indicate that the proposed method using 16QAM significantly improves the BER performance compared to the conventional method using QPSK, while maintains the spectral efficiency. Moreover, the proposed method using 64QAM concurrently improves both the BER performance and the spectral efficiency.

- Networking and Telecommunications | Pp. 586-595

On Scheduling Transmissions for Hidden Terminal Problems in Dynamic RFID Systems

Ching-Hsien Hsu; Jong Hyuk Park; Kuan-Ching Li

The problem of scheduling transmissions of dynamic Radio Frequency Identification (RFID) systems has been recently studied. One of the common problems, reader collision avoidance has instigated researchers to propose different heuristic algorithms. In this paper, we present a prime based First Come Higher Priority (FCHP) transmission scheduling method for reader collision problems that caused by hidden terminal. FCHP is a simple mechanism for coordinating simultaneous transmissions among multiple readers. A significant improvement of this approach is that FCHP prevents reader collisions by giving contention free scheduling. The second advantage of the proposed technique is that FCHP is adaptive in both static and dynamic RFID environments. The simulation results show that the proposed technique provides superior performance in both static and dynamic instances. The FCHP is shown to be effective in terms of system throughput, system efficiency and easy to implement.

- Networking and Telecommunications | Pp. 596-606

Efficient RFID Authentication Protocol for Minimizing RFID Tag Computation

Keunwoo Rhee; Jin Kwak; Wan S. Yi; Chanho Park; Sangjoon Park; Hyungkyu Yang; Seungjoo Kim; Dongho Won

RFID systems have become vital technology for realizing ubiquitous computing environments. However, features of RFID systems present potential security and privacy problems. In an effort to resolve these problems, many kinds of security and privacy enhancement technologies have been researched. However, solutions produced to date still have flaws and are not sufficiently effective for real RFID systems such as the EPCglobal network. Therefore, in this paper, to make RFID systems more secure and efficient, improved technology based on password, is proposed. The proposed technology combines an encryption algorithm with a password-derived key, and can be applied to low-cost RFID systems for enhancing the security and privacy of these systems.

- Networking and Telecommunications | Pp. 607-616

Design of WLAN Secure System Against Weaknesses of the IEEE 802.1x

Seong-pyo Hong; Jong-an Park; Seung-jo Han; Jae-young Pyun; Joon Lee

The IEEE 802.1x framework, what was known to have adjusted the IEEE 802.11b’s weakness in client authentication is a port-based control mechanism that introduces the logical port idea and performs authentication through the AP or the bridge system. Unfortunately, there are two problems in existing access authentication scheme for wireless LAN, the IEEE 802.1x. One of the problems is that it is possible for a malicious user to disguise as a right authenticator because he/she does not take into account the authentication of authenticators. The other problem is that a malicious user can force an authentication Server to waste computational resource by continuously accessing requests. In this paper, we propose a Wireless LAN secure system that offers secure encrypted communication and user authentications. The purpose of the WLAN secure system that this study suggests is to improve the weakness in security of IEEE 802.1x and to guarantee a secure encrypted communication.

- Networking and Telecommunications | Pp. 617-627

A Sophisticated Base Station Centralized Simple Clustering Protocol for Sensor Networks

Giljae Lee; Yoonjoo Kwon; Woojin Seok; Jaiseung Kwak; Okhwan Byeon

In wireless sensor networks, energy efficiency has been a key factor. So far, many energy-efficient routing protocols have been proposed and much attention has been paid to cluster-based routing protocols due to their advantages. However, some cluster-based sensor network routing protocols need location information of the sensor nodes in the network to construct clusters efficiently. Owing to the cost, it is not feasible to know the locations of all sensor nodes in the sensor network. In this paper, we propose a sophisticated base station centralized simple clustering protocol (SBCSP). The proposed protocol utilizes the remaining energy of each sensor node, standard deviation of their energy consumed and the number of cluster heads changed depending on the number of sensor nodes alive in the sensor network. Throughout the performance experiments, we show that SBCSP has better performance than low-energy adaptive clustering hierarchy (LEACH).

- Networking and Telecommunications | Pp. 628-637

Plus-Tree: A Routing Protocol for Wireless Sensor Networks

Yongsuk Park; Eun-Sun Jung

We study tree-based routing protocols for wireless sensor networks. The existing tree-based algorithm has a few shortcomings; (1) it may take a long path since sensor node must transmit packets via either its parent or its children nodes and (2) it is vulnerable to a link failure since the tree has to be reconstructed in case of a single link failure. We propose Plus-Tree, a routing protocol, which overcomes the shortcomings and improves the performance of the existing protocol. A node in Plus-Tree may have neighbor links other than tree links that can be used for alternative path. Simulation results show that Plus-Tree performs better than the existing tree-based protocol with respect to hop counts.

- Networking and Telecommunications | Pp. 638-646

Optimization and Routing Discovery for Ad Hoc Wireless Networks: A Cross Layer Approach

Reizel Casaquite; Won-Joo Hwang

Wireless communication links are time-varying in nature, causing degradation of network’s performance; this however, could be alleviated by allowing cross layer interaction in the protocol stack. Hence, optimization problems formulated in this paper considered parameters from the physical, MAC, and network layers where an optimal transmission power vector that minimizes the overall transmission power of the network, satisfying the SINR, required data rate, and maximum transmission power constraints was formulated to exist. Distributed algorithms for the joint scheduling, power control and routing were also derived and an energy-aware routing algorithm which maximizes network lifetime was proposed. The energy consumed by each node in the routing path and delays associated on each transmission were considered as link cost such that a route with minimum link cost is utilized. Basically, the routing algorithm searched an energy-efficient route, satisfying the energy constraint of each node in a routing path at a tolerable delay.

- Networking and Telecommunications | Pp. 647-658

Analysis of the Characteristics of Rain Attenuation in the 12.25GHz Band for Wireless Networking

Dong You Choi

Quantitative analysis and prediction of radio attenuation is required in order to improve reliability of satellite-earth communication links and for economically efficient design. For this reason, many countries have made efforts to develop their own rain attenuation prediction models which are fit for their rain environment. In this study the slant path length adjustment factor and rain height proposed in Korea and Japan was applied to ITU-R model (P.618-5, P.618-8), which is most widely used in the world. Their results were compared to measured data of rain attenuation and their effectiveness and validity were examined through evaluating the Pearson correlation coefficient.

- Networking and Telecommunications | Pp. 659-668


Tipo: libros

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Springer Nature

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Reino Unido

Fecha de publicación