Computational Science and Its Applications – ICCSA 2009

Requirements conflicts analysis is one of most crucial activities in successful software engineering projects. Activity diagrams are a useful standard for modeling process behaviors of systems. This paper utilizes ontological approach to analyze conflicts in the requirement specifications of activity diagrams. The proposed conflicts analysis method includes a modeling process and a set of conflicts detection rules. Several scenarios of electronic commerce are also provided for demonstrating the validity of the proposed rules. The benefits of the proposed method are threefold: (1) The method provides systematic steps for modeling requirements and ontologies. (2) This method also offers a set of questions for facilitating requirements elicitation about activity diagrams. (3) The proposed rules can systematically assist in requirements conflicts detection.

As globalization has become main phenomena in software development in the US since the year 2000, many software projects have been shipped out to other countries. Although the off-sourcing saves companies a significant amount of cost, Global Software Development (GSD) projects have created a significant challenge to the companies in terms of difference in geographical locations, time zones, and cultures. While 24-hour development model sounds to reduce the time and then the cost of software development, the expected outcome cannot be ensured if the tasks are not allocated to the proper resources in remote teams with considerations of the dependencies and constraints. In this paper, we propose an approach that can be used to reduce the overall time of GSD project development by allocating the tasks to the best possible resources based on an integrated analysis of the constraints and their impact on the overall product development.

Requirement analysis plays a very important role in reliability, cost, and safety of a software system. The use case approach remains the dominant approach during requirement elicitation in industry. Unfortunately, the use case approach suffers from several shortcomings, such as lacking accuracy and being difficult to analyze and validate the dynamic behavior of use cases for concurrency, consistency, etc. This paper proposes an approach for overcoming limitations of the use case approach and applies the approach in Model Driven Development (MDD). Timed and Controlled Petri Nets are used as the formal description and verification mechanism for the acquired requirements. Use cases are used to elicit the requirements and to construct scenarios. After specifying the scenarios, each of them can be transformed into its correspondent Petri-net model. Through analyzing these Petri-net models, some flaws or errors of requirements can be detected. The proposed approach is demonstrated by an E-mail client system.

Software is more and more built from pre-existing components. This is true also for the embedded software domain, and there is a need to consider how development processes need to be changed to best utilize the component-based paradigm, and how processes and technologies must be designed to support each other. To facilitate this change towards component-based embedded software, this paper presents a set of process guidelines, named the Progress Process Guidelines (PPG), which is based on the structure of CMMI. This paper presents the structure of the PPG, and presents and analyzes the PPG parts which most closely relate to system verification, which is typically an important and difficult activity for embedded software.

Project leaders are the most important individuals in projects. A project leader should follow some thinking styles and values which can lead his or her team to success. There is a common notion among software specialists that the more complex a project manager thinks, the better his leadership is. In this paper, we discuss the significance of simple thinking in project leadership. If the leader thinks in a simple way, then the risk of being suffocated in details is less. Complex thinking brings out greater risks of losing the general control of the system because of spending too much time and effort on details and, as a result, more confusion. Not only simplicity, but also psychological factors are important in guiding teams and developing projects in the most effective way. Here, we present a set of qualities for a good project leader in software engineering. In addition to that, we also demonstrate how cognitive and ethical issues affect leadership qualities.

Weyuker proposed the nine properties to evaluate software complexity measures at a time when procedural languages were dominant; however, several researchers have used these properties to evaluate object oriented metrics although the object-oriented (OO) features are entirely different in nature. In this paper, we evaluate each of Weyuker’s properties for its effective evaluation and relevance for OO metrics. In addition, we evaluate eleven OO metrics against language independency and additive property. A set of additional properties for object oriented metrics are also summarized in this paper.

Researchers are taking interest in the computational prediction models to efficiently predict the structure of perovskites. we are using Support Vector Regression, Artificial Neural Network, Multiple Linear Regression and SPuDS program based approaches in predicting the lattice constants (LC) of double perovskites of A

2

BB’O

6

-type. These prediction models correlate the LC to atomic parameters i.e., size of ionic radii, electro-negativity, and oxidation state. These models are developed using training data. Their performance is then estimated for validation data. To investigate the generalization capability, 48 new perovskites are also collected from recent literature. Analysis shows that SVR based proposed models are more accurate and generalized, reducing the prediction error effectively.

A detailed description of the grid implementation on the production computing grid of EGEE of a semiclassical code performing a calculation of atom-diatom reaction rate coefficients is given. An application to the N + N

2

reaction for which a massive computational campaign has been performed is reported.

A detailed description of the grid implementation on the production computing grid of EGEE of FLUSS and MCTDH quantum codes performing a calculation of atom-diatom reaction rate coefficients is given. An application to the N + N

2

reaction for which a massive computational campaign has been performed is reported.

A multiscale tridimensional Chemistry and Transport Model (Chimere) has been implemented on two very different scalable cluster. Its input was generated by specific interfaces built by the authors, adaptating meteo, emissions and boundary conditions data provided by different agencies to the needs of the Model. A prototype grid implementation on a segment of the EGEE Grid has been performed. Preliminary results of an application to the Umbria Region ozone production are also presented.

The design and management of firewall ACLs is a very hard and error-prone task. Part of this complexity comes from the fact that each firewall platform has its own low-level language with a different functionality, syntax, and development environment. Although several high-level languages have been proposed to model firewall access control policies, none of them has been widely adopted by the industry due to a combination of factors: high complexity, no support of important features of firewalls, no common development process, etc. In this paper, a development process for Firewall ACLs based on the Model Driven Architecture (MDA) framework is proposed. The framework supports the market leaders firewall platforms and is user-extensible. The most important access control policy languages are reviewed, with special focus on the development of firewall ACLs. Based on this analysis a new DSL language for firewall ACLs, AFPL2, covering most features other languages do not cover, is proposed. The language is then used as the platform independent meta-model, the first part of the MDA-based framework.

The use of virtual private networks (VPNs) for the communications protection is becoming increasingly common. Likewise, the IPSEC architecture has been gaining ground and, at present, is the solution more used for this purpose. That is the reason why a large number of implementations of IPSEC have been created and put into operation. This work proposes three testing topologies to carry out IPSEC implementation assessment, each of these scenarios will supply an important guide for the determination of objectives, digital evidences to collect and test batteries to develop, in any evaluation of a IPSEC device.

In this work, we present a mobile e-payment scenario where the merchant entity has important connectivity restrictions, which is only able of communicating through short distance connections (Wi-Fi or Bluetooth). To protect the exchange of messages, our work describes a payment protocol centered in the client which applies digital signature with recovery using self-certified public keys. Additionally, security aspects have been analyzed and protocol implementation specifications have been presented.

Recently, Liu et al. have proposed an efficient scheme for a remote user authentication using smart cards suited for a multi-server environment. This work reviews Liu et al,’s scheme and provides a security analysis on the scheme. Our analysis shows that Liu et al.’s scheme does not achieve its fundamental goal not only of mutual authentication bur also of password security. We demonstrate these by mounting a user impersonation attack and an off-line password guessing attack, respectively, on Liu et al.’s scheme.

Group key exchange protocols allow a group of parties communicating over a public network to come up with a common secret key called a

session key

. Due to their critical role in building secure multicast channels, a number of group key exchange protocols have been suggested over the years for a variety of settings. Among these is the so-called EKE-M protocol proposed by Byun and Lee for password-based group key exchange in the

different password authentication model

, where group members are assumed to hold an individual password rather than a common password. While the announcement of the EKE-M protocol was essential in the light of the practical significance of the different password authentication model, Tang and Chen showed that the EKE-M protocol itself suffers from an undetectable on-line dictionary attack. Given Tang and Chen’s attack, Byun et al. have recently suggested a modification to the EKE-M protocol and claimed that their modification makes EKE-M resistant to the attack. However, the claim turned out to be untrue. In the current paper, we demonstrate this by showing that Byun et al.’s modified EKE-M is still vulnerable to an undetectable on-line dictionary attack. Besides reporting our attack, we also figure out what has gone wrong with Byun et al.’s modification and how to fix it.

Smart card based authenticated key exchange allows a user with smartcards and the server to authenticate each other and to agree on a session key which can be used for confidentiality or data integrity. In the paper, we propose a two-round smart card based AKE (Authenticated Key Exchange) protocol using biometric information which provides mutual authentication but only requires symmetric cryptographic operations. This paper proposes a new protocol which is best suitable in pervasive computing environments thus providing efficiency in number of rounds, forward secrecy and security against known-key attack.

A receipt used for electronic voting is a key component of voting techniques designed to provide voter verifiability. In this paper, we propose electronic voting scheme involving issuing a receipt based on the cut-and-choose mechanism. Compared with Chaum

et al

.’s scheme[3], this scheme does not require large amounts of physical ballots and trust assumptions on tellers. Furthermore, it is as efficient and user-friendly as any of the existing electronic voting schemes issuing receipts described in the relevant literature. They only require simple comparisons between the screen and the receipt during voter’s voting process. This scheme is provably secure under the fact that the ElGamal encryption cryptosystem is semantically secure. We implemented the proposed scheme in according to the defined implementation requirement and provide the security analysis of the scheme.

Shi, Jang and Yoo recently proposed a provable secure key distribution and authentication protocol between user, service provider and key distribution center(KDC). The protocol was based on symmetric cryptosystem, challenge-response, Diffie-Hellman component and hash function. Despite the claim of provable security, the protocol is in fact insecure in the presence of an active adversary. In this paper, we present the imperfection of Shi et al.’s protocol and suggest modifications to the protocol which would resolve the problem.

The performance of space time block code (STBC) pulse position modulation-time hopping (PPM-TH) ultra-wide band (UWB) systems with double binary turbo coding is analyzed and simulated in multi-user environments. The channel model is considered as a modified Saleh and Valenzuela (SV) model which was suggested as a UWB indoor channel model by the IEEE 802.15.SG3a in July 2003. In order to apply the STBC scheme to the UWB system considered in this paper, the Alamouti algorithm for real-valued signals is employed because UWB signals with the pulse modulation have the type of real signal constellation. The system performance is evaluated in terms of bit error probability. From the simulation results, it is demonstrated that the double binary turbo coding technique offers considerable coding gain with reasonable encoding and decoding complexity. Also, it is demonstrated that the performance of the STBC-UWB system can be substantially improved by increasing the number of iterations in the decoding process for a fixed code rate. Also, it is confirmed that the double binary turbo coding and STBC schemes are very effective in increasing the number of simultaneous users for a given bit error probability requirement. The results of this paper can be applied to implement the down-link of the PPM-TH UWB system.

This paper evaluates the pseudo noise (PN) code acquisition with delay diversity receiver for a time hopping-ultra wideband (TH-UWB) system. The detection, overall miss detection, and false alarm probabilities, and mean acquisition time are evaluated over the hypothesis of multiple synchronous states (

H

1

cells) in the uncertainty region of the PN code. And the code acquisition performance is evaluated when the correlator output are non-coherently combined by using equal gain combining (EGC) scheme. A constant false alarm rate (CFAR) criterion is applied to the threshold setting rule. From the simulation results, it is demonstrated that the proposed acquisition system with delay diversity receiver achieves a remarkable diversity gain with reasonable complexity. The proposed acquisition scheme can be applied to the UWB base stations in order to enhance the acquisition performance with low complexity.

IEEE 802.11 is the most famous protocol for implementation of wireless local area network (WLAN). To access the medium, IEEE 802.11 uses carrier sense multiple access with collision avoidance (CSMA/CA) mechanism, called distributed coordination function (DCF). Although DCF uses binary exponential backoff (BEB) algorithm to avoid frame collisions, wireless resources are wasted due to a lot of collisions under the condition that there are many contending stations. To solve this problem, a binary negative-exponential backoff (BNEB) algorithm has been proposed and its saturation throughput was evaluated under erroneous channel condition. As extention of our previous work, this paper evaluates performance of BNEB algorithm via mathematical analysis and simulations under saturation and erroneous channel condition in terms of the MAC delay and throughput. Also, we compare the performance of DCF with BEB to that with BNEB under normal traffic and erroneous channel condition by intensive simulations. From the results, BNEB yields better performance than BEB in general.

As the evolution of high speed downlink packet access (HSDPA), long-term evolution (LTE) has being standardized by the 3rd generation partnership project (3GPP). In the existing mobile communication networks, voice traffic is delivered through circuit-switched networks, but to the contrary in LTE, all kinds of traffic are transferred through packet-switched networks based on IP. In order to provide quality of service (QoS) in wireless networks, radio resource management (RRM) is very important. To reduce network congestion and guarantee certain level of QoS for on-going calls, call admission control (CAC), in part of RRM, accepts or rejects service requests. In this paper, we proposed resource-estimated CAC algorithm and evaluated the performance of the proposed CAC algorithm. The result shows that the proposed algorithm can maximize PRB utilization and guarantee certain level of QoS.

The problem of content delivery with a required QoS is currently one of the most important. In ad-hoc networks it is IEEE 802.11 EDCA which tries to face this problem. This paper describes several EDCA line topology configurations with mixed priorities of nodes. Detailed conclusions about the innovative results help to understand the behavior of EDCA in the presence of hidden and exposed nodes. They reveal a strong unfairness in medium access between certain nodes dependent on their placement. They prove that for short lines a frequent inversion in the throughput levels of high and low priority traffic occurs and makes reliable content exchange impossible. The importance of the strength of the exposedness and hiddenness of nodes is also discussed. Furthermore, the usefulness of the four-way handshake mechanism is argued and descriptions of the known solutions to the hidden and exposed node problems are given. Finally, novel conclusions about EDCA are provided.

In cooperative amplify-and-forward (AF) system using spatially distributed relays, there exist some relay paths degrading performance because of noise enhancement. In order to alleviate the deteriorating effect of such paths, we propose adaptive generalized selection combining (GSC)/MRC and iterative GSC/MRC switching techniques based on cyclic-redundancy-check (CRC) error detection. The adaptive GSC (with order

N

)/MRC switching with

K

relays operates as follows: the destination performs initial data detection by combining the strongest

N

( < 

K

 + 1) paths, and CRC is checked for error detection. If an error is detected, MRC with all the

K

 + 1 paths is then performed. To further generalize, the iterative GSC/MRC is employed in an iterative manner conditioned on successive error detection. Our simulation results show that the proposed schemes show better diversity performance than conventional one in terms of the bit-error rate (BER), when an appropriate CRC generator polynomial is used depending on the frame size. The diversity gain of the proposed schemes become far prominent when imperfect channel estimation is assumed at the destination.

In this paper, we suggest and implement an enhanced Wireless Broadband (WiBro) Net.-based five senses multimedia technology using Web-map-oriented mobile Mash-up. The WiBro Net. in this applicative technology supports and allows Web 2.0-oriented various issues such as user-centric multimedia, individual multimedia message exchange between multi-users, and a new media-based information and knowledge sharing / participation without spatiotemporal-dependency. To inspect applicability and usability of the technology, we accomplish various experiments, which include 1) WiBro Net.-based real-time field tests and 2) ISO 9241/11 and /10-based surveys on the user satisfaction by relative experience in comparison with the AP-based commercialized mobile service. As a result, this application provides higher data rate transmission in UP-DOWN air-link and wider coverage region. Also, its average System Usability Scale (SUS) scores estimated at 83.58%, and it relatively held competitive advantage in the specific item scales such as system integration, individualization, and conformity with user expectations.

Among the various inter-agent communication models proposed for multi-agent systems so far, several group communication schemes have been issued to guarantee the transparent communication among the agents. However, in mobile agent environments where each agent has mobility in the network, those schemes are not sufficient to fully handle the topological change caused by the migration of mobile agents. Also, these group communication schemes should be secure in order for them to be practical. In this paper, we propose a secure group communication scheme which applies the hierarchical overlay ring structure of mobile agents. The proposed scheme uses the ring channel in order to cope adaptively with the change of ring topology. The ring channel has the fundamental information to construct the ring and is managed by only the mobile agent platforms. Therefore, each mobile agent does not need to directly handle the ring channel and can perform group communication regardless of the changing ring topology.

In this paper, we propose a novel code acquisition scheme called enhanced multiple-shift (EMS) for optical code division multiple access (CDMA) systems. By using multiple thresholds, the proposed EMS scheme provides a shorter mean acquisition time (MAT) than that of the conventional mutiple-shift (MS) scheme. The simulation results demonstrate that the MAT of EMS scheme is shorter than that of MS scheme in both single-user and multi-user environments.

Binary offset carrier (BOC) signal synchronization is based on the correlation between the received and locally generated BOC signals. Thus, the multiple side-peaks in BOC autocorrelation are one of the main error sources in synchronizing BOC signals. Recently, new correlation functions with no side-peak were proposed for sine and cosine phased BOC signal synchronization, respectively, by the authors [3]. In this paper, we propose new correlation functions with no side-peak for alternative BOC (AltBOC) and composite BOC (CBOC) signals by using the similar approach to the previous work.

IEEE 802.11 Distributed Coordination Function (DCF) guarantees fair transmission opportunity to stations. Channel occupation of low rate stations in IEEE 802.11 Wireless Local Area Network (WLAN) causes the performance anomaly resulting in the degradation of overall network throughput. Using cooperative communications between a high rate station and a low rate station, performance anomaly can be mitigated in IEEE 802.11 WLAN. In this paper, we propose a new cooperative Medium Access Control (MAC) protocol to remedy the performance anomaly and to improve transmission opportunities for low rate stations. We show that the proposed cooperative MAC protocol can enhance overall performance (e.g., throughput and MAC delay).

In wireless ad-hoc networks, all nodes need to have functions able to authenticate each other and so it is critical to know the trustworthiness of each node in such environments. This paper proposes an authentication system for ad-hoc networks, based on a clustering and trust model. Firstly, methods of solving authentication problems, which occur in ad-hoc networks, are discussed. Next, fuzzy logic inference is introduced, which is used as a trust evaluation method for each node and provides both local and global trust values. The reputation is used in the calculation of the trust value. Using the trust value of a trustor, a more sophisticated trust value can be computed. If a node moves from one cluster to another, the trust level of the node is determined by the certificate issued by the previous introducers. In addition, it is demonstrated that the proposed model can monitor and isolate malicious nodes in order to provide enhancements to the network’s overall authentication rate.

When some sensors in Wireless Sensor Networks (WSNs) fail or become energy-exhausted, redundant mobile sensors might be moved to cover the sensing holes created by the failed sensors. Within rugged terrains where wheeled sensors are unsuitable, other types of mobile sensors, such as hopping sensors, are needed. In this paper, we address the problem of relocating hopping sensors to the detected sensing holes. The recently studied tendency for this problem considered the shortest path to relocate the sensors; however, even when multiple suppliers are considered, the previous works merely use the shortest path algorithm repeatedly. As a result, the migration distribution is imbalanced, since specific clusters on the obtained paths could be used repeatedly. In this paper, we first analyze the impact of using multiple suppliers to relocate the hopping sensors, and propose a

R

elocation

A

lgorithm using the

M

ost

Di

sjointed

P

aths (RAMDiP). Simulation results show that the proposed RAMDiP guarantees a balanced movement of hopping sensors and higher movement success ratio of requested sensors than those of the representative relocation scheme, MinHopExt.

This paper proposes a hybrid hard/soft decode-and-forward (DF) relaying protocol with distributed turbo code (DTC), based on error detection in cooperative communications. In order to improve the performance in outage case of the channel between source and relay in uplink transmission, the relay decides whether to hard or soft decode the received signal based on the error detection before forwarding to the destination. Our simulation results show that the proposed hybrid hard/soft DF relaying outperforms conventional relaying protocols, in terms of the bit-error rate (BER) performance, in uplink cooperative communications with DTC. This is because the proposed scheme does not amplify the noise and propagate error to the destination by decoding adaptively with the help of error detection code or the use of known threshold in signal-to-noise ratio (SNR).

This paper proposes and measures the performance of an error control scheme for reliable message multicast on vehicular telematics networks, aiming at improving successful delivery ratio for the safety applications. Periodically triggered by an access point on the mobile gateway, the error recovery procedure collects the error reports from the reachable vehicles and decides the packet to retransmit considering available network bandwidth. The control scheme basically selects the message vehicles have missed most, giving additional precedence to messages belonging to a vehicle that is about to leave the gateway. The performance measurement result obtained via simulation using a discrete event scheduler shows that the proposed scheme can enhance the number of recovered messages by up to 12 % compared with the maximum selection scheme, showing better recovery ratio almost all ranges of given parameters.

A mobile agent is regarded as an attractive technology when developing distributed applications in mobile and ubiquitous computing environments. In this paper, we present ODDUGI, a java-based ubiquitous mobile agent system. The ODDUGI mobile agent system provides fault tolerance, security, location management and message delivery mechanisms in a multi-region mobile agent computing environment. We describe the architecture, design concepts and main features of the ODDUGI. In addition, we present the One-Touch Campus Service application developed on the basis of ODDUGI in mobile and ubiquitous computing environments.

Energy efficiency is one of the primary challenges to the successful application of wireless sensor networks (WSNs) since sensors can not be recharged easily once they are deployed. By carefully select the multi-hop number, energy consumption during routing process can be largely reduced and network lifetime can get prolonged. Although it is commonly agreed that multi-hop transmission is more energy efficient than direct transmission, especially when the source node is far away from sink node, how to determine the optimal hop number in both theoretical and practical network environment with constraint conditions is still a nontrivial problem. In this paper, we focus on theoretical deduction of the optimal hop number under one dimensional linear network environment. Then, we extend the deduced results to the practical sensor network. We also provide the selection of sub-optimal hop number under practical sensor network when the sensors are randomly deployed. The preliminary simulation results show that our optimal hop number based routing algorithm can save much more energy than many popular routing algorithms for WSNs.

Wireless Sensor Network (WSN) applications nowadays are an emerging avenue in which sensor localization is an essential and crucial issue. Many algorithms have been proposed to estimate the coordinate of sensors in WSNs, however, the attained accuracy in real-world applications is still far from the theoretical lower bound, Crame-Rao Lower Bound (CRLB), due to the effects of fading channels. In this paper, we propose a very simple and light weight statistical model for rang-based localization schemes, especially for the most typical localization algorithms based on received signal strength (RSS) and time-of-arrival (TOA). Our proposed method infers only the order or the nomination of given distances from measurement data to avoid significant bias caused by fading channels or shadowing. In such way, it radically reduces the effects of the degradation and performs better than existing algorithms do. With simulation of fading channels and irregular noises for both the RSS-based measurement and the TOA-based measurement, we analyze and testify both the benefits and the drawbacks of the proposed models and the localization scheme.

Swarm Intelligence (SI) inspired routing algorithms have become a research focus in recent years due to their self-organizing nature, which is very suitable to the routing problems in Mobile Ad hoc Networks (MANETs). Network topology information can be collected and updated in a distributed and autonomous way via the local interaction among ant-like agents inspired by SI. In this paper we make a comprehensive survey about various SI inspired routing algorithms for MANETs. These algorithms are explained and compared in detail based on a number of network metrics including packet delivery ratio, delay, routing overhead, delay jitter, goodput and throughput etc. It is our hope that the readers can get some hints for their future research work in the realm of SI inspired routing problems from the discussion and simulation results we provide in this paper.

This paper proposes an analysis framework which enables us to analyze the moving patterns of moving objects. To show the effectiveness of the framework, we applied the framework to analyze moving patterns of taxis based on the real-life location history data accumulated from the Taxi Telematics system developed in Jeju, Korea. The analysis aims at obtaining value-added information necessary to provide empty taxis with location recommendation services for the efficient operations of taxis. The proposed framework provides the flow chart which would have a quick look around the overall analysis process and help quickly deal with the same or similar analysis, while saving the temporal and economic costs. Data mining tool used in the framework is Enterprise Miner (E-Miner) in SAS which is one of the most widely used statistics packages and can effectively address huge amounts of log data. Especially, we perform the refined analysis by means of doing repeatedly the well-known k-means clustering method under various spatial or temporal conditions. The paper proposes the refined data mining process 1) extracting the interested dataset about meaningful information driven from the previous cluster results, 2) performing again the detailed clustering with the extracted dataset, and 3) finally extracting the value-added information such as the good pick-up spots or 4) returning the feedback. As a result, the spatiotemporal pattern analysis within the each refined clustering method makes it possible to recommend that the empty taxis go to the nearby cluster location with a high pick-up frequency statistically, resulting in the reduction of empty taxi ratio.

Containment queries for XML documents is one of the most important query types, and thus the efficient support for this type of query is crucial for XML databases. Recently, object-relational database management system (ORDBMS) vendors try to store and retrieve XML data in their products. In this paper, we propose an extensible index to support containment queries over the XML data stored as BLOB type in ORDBMSs. That is, we describe how to implement an index using the extensibility feature of an ORDBMS, and describe its usage. The main advantage of this index is user’s productivity in handling XML data in SQL language.

Modern wireless networks assume the inclusion of effective monitoring systems in its structure. These monitoring systems trace parameters of a network condition for maintenance of the control and safety. The problem of tracing data flows between clients that belong to some special set is examined. This can be realized by placement of special devices on the network channels. We propose model and method for the cost-consuming placement of such devices. The hypernets are used for a network representation. The low bound for the percentage of covered flows is obtained.

The host-based protocols, Mobile IPv6 protocol (MIPv6), Hierarchical Mobile IPv6 (HMIPv6), and Fast Mobile IPv6 (FMIPv6), require that the mobile terminals include the mobility functions. To address this issue, Proxy MIPv6 (PMIPv6), a network-based protocol, has recently emerged. Despite its advantage of easier practical application, PMIPv6 still has some weak points, disconnection and transmission delay, during handover. This paper, therefore, proposes a scheme that reduces handover latency by simplifying the user authentication procedure required when a mobile node (MN) enters a new wireless network domain. And it also saves transmission cost by storing packets in the optical buffering module of the local mobility anchor (LMA) and retransmitting those packets after handover phase. Performance evaluation conducted using an analysis model indicates that the proposed scheme shows a performance improvement of 33% over standard PMIPv6 in terms of handover latency, and 67% over Seamless handover scheme in terms of the transmission cost due to the retransmission of buffered packets.

Wireless link capacity within a sensor network has direct impact on its performance and throughput. Due to dense sensor deployment, interference seems to be a key factor for varying radio link capacity and also for congestion at hot spot region. Thus it is important to handle interference while removing in-network hot spots. The main goal of this paper is to achieve maximum utilization of link capacity for each sensor node controlling congestion related packet losses. Therefore in this paper we proposed an interference and capacity aware data transport protocol for sensor networks which performs rate control over congested wireless links. Proposed approach identifies the congested links that exists in hot spots and then adapts data transmission rate of corresponding sensor nodes. Perception of radio link interferences i.e. intra-path and inter-path interferences are used to estimate the capacity of each link. Finally simulation outputs have demonstrated the effectiveness of the proposed task and showed a noticeable performance in terms of packet delivery ratio, packet delivery latency and sensor’s runtime buffer size.

Vehicular Ad Hoc Networks (VANETs) have received large attention in recent times. There are many applications bringing out the new research challenges in the VANET environment such as vehicle to vehicle communication, road-side vehicle networking etc. Road-side data access in the two intersecting roads of downtown area in VANET is the main consideration of this paper. Caching is a common technique for saving network traffic and enhance response time, especially in wireless environments where bandwidth is often a scare resource. In this paper, a novel Road-Side Information Station (RIS) data distribution model with cache scheme in VANET for the data access in the two intersecting roads of downtown area is proposed. The performance of the proposed scheme is tested through simulations. The simulation results reveal that the proposed scheme can significantly improve the response time, and the network performance.

Supporting multimedia traffic is one of the major challenges for the next generation of wireless personal area networks (WPANs). Especially, the IEEE 802.15.4 WPAN standards specify how to guarantee real-time traffic with a type of time division multiple access (TDMA), called the guaranteed time slots (GTS). The GTS mechanism has led many researchers to design techniques aiming to support various real-time applications within the delay jitter. Since the IEEE 802.15.4 standards can operate at low data rate up to 250Kbps, it is limited to guarantee real-time multimedia traffic except voice. The voice traffic has bidirectional characteristics and may go through the multihop in WPAN which can support short-range communications among electronic devices. In this paper, we introduce a virtual cut-through GTS allocation mechanism, namely VC-GTS allocation, for voice traffic in multihop IEEE 802.15.4 systems. The proposed scheme can support bidirectional voice traffic and delivery the traffic to the destination through multihop paths with the minimum end-to-end delay time. The most important thing is that our proposed scheme achieves low delay time and packet error rate without a complex allocation algorithm in multihop IEEE 802.15.4 networks. Our simulation results show that our new scheme outperforms the basic IEEE 802.15.4 GTS mechanism.

Recently, ubiquitous location-based services (u-LBS) has been utilized in a variety of practical and mission-critical applications such as security services, personalization services, location-based entertainment, and location-based commerce. The essence of u-LBS is actually the concept of

location-awareness

where location-aware devices perform more intelligent services for users by utilizing their locations. In order to realize/achieve this concept, a mobile device should continuously monitor the real-time contextual changes of a user; this is what we call

location-based monitoring

. In this paper, we discuss the research and technical issues on designing location-based real-time monitoring systems in u-LBS along with three major subjects: (1) high-performance spatial index, (2) monitoring query processing engine, and (3) distributed monitoring system with dynamic load balancing capability and energy-efficient management.

Given a set of elements

N

, a partition consists on dividing the set of elements into two or more disjoint clusters that cover all elements. A cluster contains a non-empty subset of elements. The number of clusters of a partition is less than or equal to |

N

|. Different partitioning algorithms for the same application will produce different partitions from the same set of elements. To compute the distance and find the consensus partition (also called as consensus clustering) between two or more partitions are important and interesting problems that arise in many applications such as bioinformatics and data mining. However, different distance functions between two or more partitions will usually need to be computed by different algorithms. In this paper, we discuss the k partition-distance problem which can be applied in bioinformatics. Given a set of elements

N

with k partitions, the k partition-distance problem is to delete the minimum number of elements from each partition such that all remaining partitions become identical. However, this problem has been shown to be NP-complete when

k

 > 2. We will present the first known approximation algorithm with performance ratio 2 to solve this problem in

$O(k*\rho*|N|)$

time, where

ρ

is the maximum number of clusters of these

k

partitions. Then we perform our algorithm for simulation of random data and actual the set of organisms based on DNA markers. It will show that our approximation solution is at most twice the partition-distance of the optimal solution in practice.

Recently, Particle Swarm Optimization (PSO), gained vast attention and applied to variety of engineering optimization problems because of its simplicity and efficiency. The performance of the PSO algorithm can be further improved by hybrid techniques. There are numerous hybrid PSO algorithms published in the literature where researchers combine the benefits of PSO with other heuristic algorithms. In this paper, we propose a cooperative line search particle swarm optimization (CLS-PSO) algorithm by integrating local line search technique and standard PSO (S-PSO). The performance of the proposed hybrid algorithm, examined through six typical nonlinear optimization problems, is reported. Our experimental results show that CLS-PSO outperforms S-PSO.

We propose some new approaches to the problem of obtaining the reliability polynomial of a random graph. The meaning of coefficients of the reliability polynomial in one of its presentation is used for the significant reducing of calculations while the factoring method underlies. Experiments shows significant speeding up in compare with well known package Maple 11 (up to 2000 times on the standard lattice example).

Numerous data structures are developed to organize data and their relations. Point set data in GIS are managed mostly through TIN (Triangulated Irregular Network) or grid structure. Both methods have some disadvantages which will be discussed in this paper. In order to remove these weaknesses, a novel method will be introduced which is based on tree graph data structure. Tree graph data structure is a kind of data structure which shows the relationship between points by using some tree graphs. This paper assesses the commonly used point structures. It then introduces a new algorithm to address the issues of previous structures. The new data structure is inspired by snow falling process in natural environment. In order to evaluate the proposed data structure, a Digital Train Model (DTM) of sample points is constructed and compared with the generated DTM of TIN model. The RMSE of proposed method is 0.585933 while the one which is obtained by TIN method is 0.748113. The details of which are presented in the paper.

Dependability can be verified at the integration phase of the software development life cycle. However the dependability verification processes that inspect software dependability in the late period of development have an effect in the development cost (e.g. time, human resources). Therefore, it is a very important issue to verify any nonfunctional requirements in the early stages of the development process. In this paper, we propose a software dependability analysis methodology of distributed component based software by using HQPNs (Hierarchically Combined Queuing Petri Nets) modeling. We prove the validity of the proposed methodology by applying it to a video conference system development.

In this paper, we propose a new approach for the pricing of bond options using the relation between the Heath-Jarrow-Morton (HJM) model and the Brace-Gatarek-Musiela (BGM) model. To derive a closed-form solution (CFS) of bond options on the HJM model with the BGM model, we first consider about basic concepts of the HJM model in which is hard to achieve the CFS of bond options. The second obtains the bond pricing equation through the fact that the spot rate is equal to the instantaneous forward rate. Furthermore, we derive the formula of the discount bond price using restrictive condition of Ritchken and Sankarasubramanian (RS). Finally, we get a CFS of bond options using the relation between the HJM volatility function

σ

f

(

t

,

T

) and the BGM volatility function

λ

(

t

,

T

) and give the analytic proof of bond pricing. In particular, we can confirm the humps in the pricing of bond call option occur while the graph of bond put option are decreasing functions of the maturity as the value of

δ

(tenor) and

σ

r

(volaitility of interest rate) are increasing with two scenarios. This result means a simple and reasonable estimate for the pricing of bond options under the proposed conditions.

In [1] a formulation of anonymity based on metrics of Probabilistic Applied Pi processes was proposed. As an extension to [1], we consider to neglect all the internal interactions in the definition of metric. In other words, the new metric between two processes turns out to be 0 when these two processes are weakly bisimilar (strongly bisimilar in [1]). Upon metric, the degree of probabilistic anonymity is modelled for general anonymous systems where there are no explicit senders or receivers. In addition, we devise an algorithm to calculate the metric between two finite processes. As a running example, we analyze the classical anonymous protocol — Probabilistic Dining Cryptographer Problem — to illustrate the effectiveness of our approach.

Variational data assimilation consists in estimating control parameters of a numerical model in order to minimize the misfit between the forecast values and some actual observations. The gradient based minimization methods require the multiplication of the transpose jacobian matrix (adjoint model), which is of huge dimension, with the derivative vector of the cost function at the observation points. We present a method based on a

modular graph

concept and two algorithms to avoid these expensive multiplications. The first step of the method is a propagation algorithm on the graph that allows computing the output of the numerical model and its linear tangent, the second is a backpropagation on the graph that allows the computation of the adjoint model. The YAO software implements these two steps using appropriate algorithms. We present a brief description of YAO functionalities.

With highly dynamic, structured P2P system needs very high maintenance cost. In this paper we propose a Clone Node Protocol to reduce the maintenance cost of structured P2P system by a mechanism of clone nodes. In order to verify the efficiency of CNP, we achieve a Clone Node Chord structure based on CNP, i.e. CNChord. Furthermore, we implement a bidirectional CNChord (BCNChord) in order to reduce query time of CNChord. Theoretical analysis and experimental results show that CNChord can greatly reduce the cost of maintaining P2P structure and BCNChord can effectively improve the query speed. In a word, CNP can effectively reduce the maintenance cost of structured P2P.

SCADA is a set of systems with a higher automatic level of the long-distance pipeline. When the sub-transmission stations in the state of full load, the automatic control of sub-output capacity is quite stable working at certain settings. However, partly sub-transmission stations sub-output capacity is far less than the design of sub-output capacity in actual projects, which makes the PLC parameter of the control system in the stations difficult to set. And unstable sub-output often appears. This paper gives the optimizing design to achieve stable sub-output in small flow, and gives the algorithms to achieve better effects for sub-output control on the practical spots under the condition of unchanging the original structure of the system.

An on-demand chaotic noise injection strategy for Broadcast Scheduling Problem (BSP) based on an adjacency matrix is described in this paper. Packet radio networks have many applications especially for military purposes while finding an optimized scheduling to transmit data is proven to be a NP-hard domain problem. The objective of the proposed method is to find an optimal time division multiple access (TDMA) frame based on maximizing channel utilization. The proposed method benefits from an on-demand noise injection policy which, unlike previous Noise Chaotic Neural Networks (NCNN) that suffers from blind injection policy, injects noise based on the status of neuron and its neighborhoods. The experimental result shows that in most cases the on-demand noise injection finds the best solution with minimal average time delays and maximum channel utilization in comparison to previous methods.

The research tracks the spread of co-occurrence phenomena over the zonal space. Spread patterns of spatio-temporal co-occurrences over zones (SPCOZs) represent the spread structures over the zones for the subsets of features whose events co-locate in space and time. SPCOZs are of great use in many applications, such as tracking the evolutions of infectious diseases and ecological disasters in space and time. However, finding SPCOZs is computationally expensive due to large size of history data sets, exponential number of feature combinations, and complex interest measures. In this paper, we propose a novel Spread Pattern Tree (SP-Tree) to index the spread elements of the SPCOZs which holds the monotonic property with the size of the co-occurrences. We also propose an efficient mining algorithm (SPCOZ-Miner) for mining SPCOZs. The experimental evaluation with both synthetic and real-world data sets shows our algorithm is effective and much more efficient than a straight approach.

The main purpose of pulmonary nodule detection is to classify nodule from the lung computed tomography (CT) images. The variability of class is mainly expected to the grey-level variance, texture differences and shape. The purpose of this study is to develop a nodule detector based on Two-dimensional Principal Component Analysis (2DPCA). We extract the features using 2DPCA from nodule candidate images. Nodule candidates are then classified using threshold. The proposed method significantly reduces false positive (FP) rate. We applied it to Lung Imaging Database Consortium (LIDC) database of National Cancer Institute (NCI). The experimental results show the effectiveness and efficiency of the proposed method. The proposed method achieved 80.60% detection rate with 0.0391 FPs per slice.

The paper presents an original statistical approach dedicated to the evaluation of two time intervals which are useful in various chaotic applications, namely: the transient time and the minimum statistical independence sampling distance. The overall procedure relies on Smirnov tests based on two-sample statistic, Kolmogorov-Smirnov tests based on one-sample statistic, a Monte Carlo analysis and an original statistical independence test. The experimental study was performed on the logistic map for different values of its parameter, values considered of much interest in the literature. The proposed statistical approach may guide another experimenter to extend the analysis for other logistic map parameters and also for other chaotic maps.

Personal Health Records (PHRs) and other emerging health information technologies create the potential for the capture and storage of a much greater quantity and quality of health data in the future. PHRs in particular provide a likely more privacy supporting form of electronic health data storage. This paper discusses how new health information technologies can support richer future health record data and how these records can provide a foundation for current and future applications of computational science approaches, supporting what might be called Computational Health.

This paper proposes an approach to decision analysis for complex industrial process without enough knowledge of input-output model, which is based on the two-class SVM method. It first proposes a SVM Based Decision Analysis Model to improve the accuracy of determinant of whether a decision is acceptable/ unacceptable by verifying the ‘soft margin’ of a SVM. This makes it only allow misclassification of only one class in a two-class classification. Then a granular-based approach is presented to solving this model. It is proved that this granular approach can reach an upper bound of the original SVM model. An algorithm then is presented to determine whether a decision is acceptable. According to our analysis and experiments, the two types of SVM have better accuracy on judging its target class then traditional SVM, and the granular-based SVM solving can reduce the running time.

In this paper we present the improved Fast Time Series Evaluation(IFTSE) algorithm that can fast and efficiently track the objects in bad environment conditions. Object tracking in intelligent surveillance system is an important part to identify suspicious objects’ behavior. But object tracking is exhaustive and time-consuming process and we cannot also efficiently search the trajectory of detected objects due to bad conditions (e.g. bad camera capacity, dust particles in the air, lighting changes). To demonstrate the performance of the proposed IFTSE algorithm for tracking the objects, we introduce evaluation metrics. A prototype tracking system that IFTSE algorithm is employed is implemented using Visual C++. We increase true positive rate by approximately 6% and reduce false alarm rate by approximately 2% and reduce id change by approximately 30%.

Efficient skin detection can be considered as a primary work for so many vital applications in the image processing arena. For the last few years researchers have been trying in several ways to solve this problem. But most of the methods suffer from accuracy and reliability when applied to a variety of images. This happens due to some significant factors such as error in skin model, use of predefined threshold. We combine these issues by proposing an improved approach for skin detection that uses Dempster Shafer Theory of evidence to build a skin prediction model with better reliability. The proposed approach gives higher accuracy for a variety of skin images than existing methods in considerable computation time (similar to Bayesian classifier) and suitable for real-time applications.

In this paper, we propose a novel shot boundary detection algorithm using Generalized Eigenvalue Decomposition (GED). We derive a theorem that discuss about some new features of GED which could be used in the video processing algorithms. Our innovative explanation utilizes this theorem in the detecting of boundaries of video shots. Experimental results and comparison with publicly available shot detection systems on TRECVID 2006 datasets are reported.

The assessment of content quality (CQ) in social media adds a layer of complexity over traditional information quality assessment frameworks. Challenges arise in accurately evaluating the quality of content that has been created by users from different backgrounds, for different domains and consumed by users with different requirements. This paper presents a comprehensive review of 19 existing CQ assessment related frameworks for social media in addition to proposing directions for framework improvements.

Many drawbacks has been found in Hu’s moment Invariant or known as Geometric Moment Invariant (GMI). Due to its flexibility, GMI is still widely used by the researchers until now. This paper proposes an alternative approach, Weighted Aspect Moment Invariant (WAMI) by combining Weighted Central Moment (WCM) and Aspect Moment Invariant (AsMI) to solve GMI’s drawbacks in term of noise and unequal data scaling. Various insect images are used in this study with two different sizes as simulation images. The simulation results show that the proposed WAMI improves inter-class and intra-class criteria for unequally scaling data compared to AsMI.

Existing work on

k

nearest neighbor (

k

NN) in spatial/mobile query processing focuses on single object types. Furthermore, they do not consider optimum path in KNN. In this paper, we focus on multiple type

k

NN whereby the interest points are of multiple types. Additionally, we also consider an optimum path to reach the interest points. We propose three different query types involving multiple object types. Our algorithms adopt the network Voronoi Diagram (NVD). We describe two ways to solve multiple types of KNN queries: one is to create NVD for each object type, and two is to create one NVD for all objects. The comparison between these two approaches is presented in performance evaluation section.

Publish-Subscribe paradigm has been widely employed in Real-Time applications. However, the existing technologies and models only support a simple binary concept of matching: an event either matches a subscription or it does not; for instance, a production monitoring event will either match or not match a subscription for production anomaly. Based on adaptive Quality of Service (QoS) management, we propose a novel publish/subscribe model, which is implemented as a critical service in a real-time database

Agilor

. We argue that publications have different relevance to a subscription. On the premise of guaranteeing deadline

d

, a subscriber approximately receives

k

most relevant publications, where

k

and

d

are parameters defined by each subscription. After the architecture of our model is described, we present negotiations between components and scalable strategies for adaptive QoS management. Then, we propose an efficient algorithm to select different strategies adaptively depending on estimation of current QoS. Furthermore, we experimentally evaluate our model on real production data collected from manufacture industry to demonstrate its applicability in practice.

This paper studies a networking packet management for a protocol processor in a network terminal. The network terminal is to handle high-speed data streams, more than 10 Gb/s. We developed an algorithm, which distributes the packet losses evenly among the different applications. Our experimental results show that the proposed algorithm improves the packet loss ratio more than 15% compared to conventional dynamic algorithm.

In pervasive ad-hoc networks, there is a need for devices to be able to communicate securely, despite the lack of apriori shared security associations and the absence of an infrastructure such as a PKI. Previous work has shown that through the use of short verification strings exchanged over manual authentication channels, devices can establish secret session keys. We examine a construction of such a cryptographic digest function for deriving the verification string, and propose an improved construction, with weaker assumptions. We further provide a concrete instantiation which is efficient, based on finite fields.

The accurate prediction of Web navigation patterns has immense commercial value as the Web evolves into a primary medium for marketing and sales for many businesses. Often these predictions are based on complex temporal models of users’ behavior learned from historical data. Such an approach, however, is not readily understandable by business people and hence less likely to be used. In this paper, we consider several key and practical Web navigation patterns and present Bayesian models for their learning and prediction. The navigation patterns considered include pages (or page categories) visited in first

N

positions, type of visit (short or long), and rank of page categories visited in first

N

positions. The patterns are learned and predicted for specific users, time slots, and user-time slot combinations. We employ Bayes rule and Markov chain in our learning and prediction models. The focus is on accuracy and simplicity rather than modeling the complex Web user behavior. We evaluate our models on four weeks of Web navigation data. Prediction models are learned from the first three weeks of data and the predictions are tested on last week’s data. The results confirm the high accuracy and good efficiency of our models.

Many IP forwarding engines have employed TCAM for lookup operations due to its capability of storing variable-sized network prefixes. Power consumption has been one of the most important issues in TCAM-based engines. In contrast, SRAM can be operated with low power and latency but it cannot store variable-sized data directly. While it may need several accesses per lookup, TCAM needs only one access because of its parallel search. In this paper we propose a hybrid IP forwarding engine which elaborately combines TCAM and SRAM to allow both low power and high throughput. It consists of three stages based on different kinds of memories. Each stage may or may not be operated depending on a given IP address to maximize performance and save energy. Experiment results show that the proposed engine is at least 7.3 times faster than the normal TCAM-based engine with only 1.8% energy of that engine.

Individuals have different backgrounds, motivation and preferences in their own learning processes. Web-based systems that ignore these differences have difficulty in meeting learners’ needs effectively. One of these individual differences is the learning style. For providing adaptively incorporated learning styles, firstly learning styles of learners have to be identified. There are many different learning models in literature. This study is based on Felder and Silverman’s Learning Styles Model and investigates only active/reflective and visual/verbal dimensions of this model. Instead of filling out a questionnaire, learner behaviors are analyzed with the help of literature-based approaches so that learning styles of learners can be detected.

Nowadays, the research of focused crawler approaches the field of semantic web, along with the appearance of increasing semantic web documents and the rapid development of ontology mark-up languages. Semantic focused crawlers are a series of focused crawlers enhanced by various semantic web technologies. In this paper, we make a survey in this research field. We discover eleven semantic focused crawlers from the existing literature, and classify them into three categories – ontology-based focused crawlers, metadata abstraction focused crawlers and other semantic focused crawlers. By means of a multi-dimensional comparison, we conclude the features of these crawlers and draw the overall state of the art of this field.

Research and developments in Semantic Grid computing has gained much attention in areas of knowledge discovery, medical sciences, business world, among others. Dealing with large domain ontology in this computing environment and its complexity becomes a daunting task. The idea of ontology tailoring is to cope up and minimize the complexity in dealing with large domain ontology and to provide services for ontology reuse, extension, addition, merging, and replace. In this paper, we tackle the task in developing the models to provide the above-mentioned services and the framework for workflow composition in ontology tailoring using UML-based design. Workflow validations were conducted to verify towards realizing a workable ontology tailoring schemes.

Utilizing the Contourlet’s advantages of multiscale, localization, directionality and anisotropy, a new SAR image segmentation algorithm based on hidden Markov tree (HMT) in Contourlet domain and dempster-shafer (D-S) theory of evidence is proposed in this paper. The algorithm extends the hidden Markov tree framework to Contourlet domain and fuses the clustering and persistence of Contourlet transform using HMT model and D-S theory, and then, we deduce the maximum a posterior (MAP) segmentation equation for the new fusion model. The algorithm is used to segment the real SAR images. Experimental results and analysis show that the proposed algorithm effectively reduces the influence of multiplicative speckle noise, improves the segmentation accuracy and provides a better visual quality for SAR images over the algorithms based on HMT-MRF in the wavelet domain, HMT and MRF in the Contourlet domain, respectively.