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Research Collection School Of Computing and Information Systems

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On Security Notions For Steganalysis, Kisik Chang, Robert H. Deng, Feng Bao, Sangjin Lee, Hyungjun Kim, Jongin Lim Dec 2004

On Security Notions For Steganalysis, Kisik Chang, Robert H. Deng, Feng Bao, Sangjin Lee, Hyungjun Kim, Jongin Lim

Research Collection School Of Computing and Information Systems

There have been some achievements in steganalysis recently. Many people have been making strides in steganalysis. They have approached steganalysis from different angles; from information theory to complexity theory. Anderson gave a possibility that there is a provable secure steganographic system, but there had not been complexity theoretical approaches for years. In 2002, Katzenbeisser and Petitcolas defined the conditional security of steganography and gave a possibility for a practical, provable secure steganography for the first time, and Hopper et al. introduced a provable secure steganographic algorithm in the sense of complexity theory. Chang et al. also tried to define the …


U-Commerce: Emerging Trends And Research Issues, H. Galanxhi-Janaqi, Fiona Fui-Hoon Nah Dec 2004

U-Commerce: Emerging Trends And Research Issues, H. Galanxhi-Janaqi, Fiona Fui-Hoon Nah

Research Collection School Of Computing and Information Systems

Ubiquitous commerce or u-commerce is the combination of traditional e-commerce and wireless, television, voice and silent commerce. U-commerce implies ubiquity, universality, uniqueness and unison. It is not a replacement for other types of commerce, but an extension of them. While bringing many benefits, there are challenges and impediments to overcome. Research is needed to assess the value of u-commerce and to address its related issues and challenges. Questions that need to be addressed are: What is the value of u-commerce? What are the ways to maximize the benefits and value of u-commerce? Is it the right technology and what directions …


Vertical Sensitivity For The Information Security Health Rating Of Enterprises, Arcot Desai Narasimhalu, Nagarajan Dayasindhu, Raghavan Subramanian Dec 2004

Vertical Sensitivity For The Information Security Health Rating Of Enterprises, Arcot Desai Narasimhalu, Nagarajan Dayasindhu, Raghavan Subramanian

Research Collection School Of Computing and Information Systems

INFOSeMM Maturity model was developed jointly by SMU and Infosys. It is recognized that different industry verticals will have different levels of recommended maturity levels. This paper articulates the need for developing the industry vertical benchmarks.


Method For Identifying Individuals, Manoj Thulasidas Dec 2004

Method For Identifying Individuals, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A method and system for identifying a subject comprises obtaining a digitised recording of an electrocardiogram measurement of the subject to be identified, the digitised recording being a cyclic waveform having a peak amplitude. The digitised recording is normalised to reduce variations due to physiological effects, and the normalised recording is processed to determine a feature vector in the frequency domain. The distance between the determined feature vector and a predetermined feature vector is measured to identify the subject.


Factors Impacting E-Government Development, Keng Siau, Y. Long Dec 2004

Factors Impacting E-Government Development, Keng Siau, Y. Long

Research Collection School Of Computing and Information Systems

E-government is a way for governments to use new technologies such as the Internet to provide citizens with more convenient access to government information and services, to improve the quality of services, and to provide greater opportunities for citizens to participate in democratic institutions and processes. This research investigates factors impacting e-government development. Based on the growth theory and human capital theory from the economics literature, we hypothesize that information and computer technology, and human development are two factors impacting e-government development. The hypotheses were empirically tested using secondary data from the United Nations and the United Nations Development Programme. …


Two-Echelon Repairable Item Inventory System With Limited Repair Capacity Under Nonstationary Demands, Hoong Chuin Lau, Huawei Song Nov 2004

Two-Echelon Repairable Item Inventory System With Limited Repair Capacity Under Nonstationary Demands, Hoong Chuin Lau, Huawei Song

Research Collection School Of Computing and Information Systems

We study a repairable item inventory system under limited repair capacity and nonstationary Poisson demands, motivated by corrective maintenance of military equipment. Our goal is to minimize the cost of both spare and repair resource allocation. We propose an efficient analytical model that combines optimization modeling and queuing theory.


Corrective Maintenance Optimization In An Air Force, Hoong Chuin Lau, K. Y. Neo, W. C. Wan Nov 2004

Corrective Maintenance Optimization In An Air Force, Hoong Chuin Lau, K. Y. Neo, W. C. Wan

Research Collection School Of Computing and Information Systems

Successful military mission planning and execution depend critically on equipment serviceability and resupply. Due to the stochastic nature of demands, the forecast of optimal spares and resources needed to guarantee the level of serviceability is a complex problem, especially in a multi-echelon setting. In this paper, we propose a decision-support concept and software tool known as Corrective Maintenance Optimizer (CMO) that helps to optimize system availability, through proper allocation of spare parts, both strategically and operationally.


Job Scheduling With Unfixed Availability Constraints, Hoong Chuin Lau, C. Zhang Nov 2004

Job Scheduling With Unfixed Availability Constraints, Hoong Chuin Lau, C. Zhang

Research Collection School Of Computing and Information Systems

Standard scheduling theory assumes that all machines are continuously available throughout the planning horizon. In many manufacturing and service management situations however, machines need to be maintained periodically to prevent malfunctions. During the maintenance period, a machine is not available for processing jobs. Hence, a more realistic scheduling model should take into account machine maintenance activities. In this paper, we study the problem of job scheduling with unfixed availability constraints on a single machine. We first propose a preliminary classification for the scheduling problem with unfixed availability constraints based on maintenance constraints, job characteristics and objective function. We divide our …


Finding Constrained Frequent Episodes Using Minimal Occurrences, Xi Ma, Hwee Hwa Pang, Kian-Lee Tan Nov 2004

Finding Constrained Frequent Episodes Using Minimal Occurrences, Xi Ma, Hwee Hwa Pang, Kian-Lee Tan

Research Collection School Of Computing and Information Systems

Recurrent combinations of events within an event sequence, known as episodes, often reveal useful information. Most of the proposed episode mining algorithms adopt an apriori-like approach that generates candidates and then calculates their support levels. Obviously, such an approach is computationally expensive. Moreover, those algorithms are capable of handling only a limited range of constraints. In this paper, we introduce two mining algorithms - episode prefix tree (EPT) and position pairs set (PPS) - based on a prefix-growth approach to overcome the above limitations. Both algorithms push constraints systematically into the mining process. Performance study shows that the proposed algorithms …


Accommodating Instance Heterogeneities In Database Integration, Ee Peng Lim, Roger Hsiang-Li Chiang Nov 2004

Accommodating Instance Heterogeneities In Database Integration, Ee Peng Lim, Roger Hsiang-Li Chiang

Research Collection School Of Computing and Information Systems

A complete data integration solution can be viewed as an iterative process that consists of three phases, namely analysis, derivation and evolution. The entire process is similar to a software development process with the target application being the derivation rules for the integrated databases. In many cases, data integration requires several iterations of refining the local-to-global database mapping rules before a stable set of rules can be obtained. In particular, the mapping rules, as well as the data model and query model for the integrated databases have to cope with poor data quality in local databases, ongoing local database updates …


A Periodic-Review Inventory Model With Application To The Continuous-Review Obsolescence Problem, Yuyue Song, Hoong Chuin Lau Nov 2004

A Periodic-Review Inventory Model With Application To The Continuous-Review Obsolescence Problem, Yuyue Song, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

In this paper we consider a stochastic-demand periodic-review inventory model with sudden obsolescence. We characterize the structure of the optimal policy and propose a dynamic programming algorithm for computing its parameters. We then utilize this algorithm to approximate the solution to the continuous-review sudden obsolescence problem with general obsolescence distribution. We prove convergence of our approximation scheme, and demonstrate it numerically against known closed-form solutions of special cases.


Anonymous Secure Routing In Mobile Ad-Hoc Networks, Bo Zhu, Zhiguo Wan, Mohan S. Kankanhalli, Feng Bao, Robert H. Deng Nov 2004

Anonymous Secure Routing In Mobile Ad-Hoc Networks, Bo Zhu, Zhiguo Wan, Mohan S. Kankanhalli, Feng Bao, Robert H. Deng

Research Collection School Of Computing and Information Systems

Although there are a large number of papers on secure routing in mobile ad-hoc networks, only a few consider the anonymity issue. In this paper, we define more strict requirements on the anonymity and security properties of the routing protocol, and notice that previous research works only provide Weak Location Privacy and Route Anonymity, and are vulnerable to specific attacks. Therefore, we propose the Anonymous Secure Routing (ASR) protocol that can provide additional properties on anonymity, i.e. Identity Anonymity and Strong Location Privacy, and at the same time ensure the security of discovered routes against various passive and active attacks. …


Spatial Queries In Wireless Broadcast Systems, Baihua Zheng, Wang-Chien Lee, Dik Lun Lee Nov 2004

Spatial Queries In Wireless Broadcast Systems, Baihua Zheng, Wang-Chien Lee, Dik Lun Lee

Research Collection School Of Computing and Information Systems

Owing to the advent of wireless networking and personal digital devices, information systems in the era of mobile computing are expected to be able to handle a tremendous amount of traffic and service requests from the users. Wireless data broadcast, thanks to its high scalability, is particularly suitable for meeting such a challenge. Indexing techniques have been developed for wireless data broadcast systems in order to conserve the scarce power resources in mobile clients. However, most of the previous studies do not take into account the impact of location information of users. In this paper, we address the issues of …


On Semantic Caching And Query Scheduling For Mobile Nearest-Neighbor Search, Baihua Zheng, Wang-Chien Lee, Dik Lun Lee Nov 2004

On Semantic Caching And Query Scheduling For Mobile Nearest-Neighbor Search, Baihua Zheng, Wang-Chien Lee, Dik Lun Lee

Research Collection School Of Computing and Information Systems

Location-based services have received increasing attention in recent years. In this paper, we address the performance issues of mobile nearest-neighbor search, in which the mobile user issues a query to retrieve stationary service objects nearest to him/her. An index based on Voronoi Diagram is used in the server to support such a search, while a semantic cache is proposed to enhance the access efficiency of the service. Cache replacement policies tailored for the proposed semantic cache are examined. Moreover, several query scheduling policies are proposed to address the inter-cell roaming issues in multi-cell environments. Simulations are conducted to evaluate the …


The D-Tree: An Index Structure For Planar Point Queries Location-Based Wireless Services, Jianliang Xu, Baihua Zheng, Wang-Chien Lee, Dik Lun Lee Nov 2004

The D-Tree: An Index Structure For Planar Point Queries Location-Based Wireless Services, Jianliang Xu, Baihua Zheng, Wang-Chien Lee, Dik Lun Lee

Research Collection School Of Computing and Information Systems

Location-based services (LBSs), considered as a killer application in the wireless data market, provide information based on locations specified in the queries. In this paper, we examine the indexing issue for querying location-dependent data in wireless LBSs; in particular, we focus on an important class of queries, planar point queries. To address the issues of responsiveness, energy consumption, and bandwidth contention in wireless communications, an index has to minimize the search time and maintain a small storage overhead. It is shown that the traditional point-location algorithms and spatial index structures fail to achieve either objective or both. This paper proposes …


Logistics Network Design With Differentiated Delivery Lead Time: A Chemical Industry Case Study, Michelle Lee Fong Cheong, Rohit Bhatnagar, Stephen C. Graves Nov 2004

Logistics Network Design With Differentiated Delivery Lead Time: A Chemical Industry Case Study, Michelle Lee Fong Cheong, Rohit Bhatnagar, Stephen C. Graves

Research Collection School Of Computing and Information Systems

Most logistics network design models assume exogenous customer demand that is independent of the service time or level. This paper examines the benefits of segmenting demand according to lead-time sensitivity of customers. To capture lead-time sensitivity in the network design model, we use a facility grouping method to ensure that the different demand classes are satisfied on time. In addition, we perform a series of computational experiments to develop a set of managerial insights for the network design decision making process.


Structuring Home Video By Snippet Detection And Pattern Parsing, Zailiang Pan, Chong-Wah Ngo Oct 2004

Structuring Home Video By Snippet Detection And Pattern Parsing, Zailiang Pan, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Hand-held camcorders have been popularly used in capturing and documenting daily lives. Nonetheless, searching for personal memories in home videos is still a laborious task. This paper describes novel approaches in detecting snippets and patterns in home videos for content indexing. To deal with the fact that most shots are long and with handshake artifacts, a motion analysis algorithm based on Kalman filter and finite state machine is proposed to decompose videos into tables of snippets. Each snippet is represented by a set of moving and static patterns. The moving patterns are automatically detected and tracked, while the static patterns …


Clip-Based Similarity Measure For Hierarchical Video Retrieval, Yuxin Peng, Chong-Wah Ngo Oct 2004

Clip-Based Similarity Measure For Hierarchical Video Retrieval, Yuxin Peng, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

This paper proposes a new approach and algorithm for the similarity measure of video clips. The similarity is mainly based on two bipartite graph matching algorithms: maximum matching (MM) and optimal matching (OM). MM is able to rapidly filter irrelevant video clips, while OM is capable of ranking the similarity of clips according to the visual and granularity factors. Based on MM and OM, a hierarchical video retrieval framework is constructed for the approximate matching of video clips. To allow the matching between a query and a long video, an online clip segmentation algorithm is also proposed to rapidly locate …


Comments On "A Practical (T, N) Threshold Proxy Signature Scheme Based On The Rsa Cryptosystem", Guilin Wang, Feng Bao, Jianying Zhou, Robert H. Deng Oct 2004

Comments On "A Practical (T, N) Threshold Proxy Signature Scheme Based On The Rsa Cryptosystem", Guilin Wang, Feng Bao, Jianying Zhou, Robert H. Deng

Research Collection School Of Computing and Information Systems

In a (t, n) threshold proxy signature scheme based on RSA, any t or more proxy signers can cooperatively generate a proxy signature while t-1 or fewer of them can't do it. The threshold proxy signature scheme uses the RSA cryptosystem to generate the private and the public key of the signers. In this article, we discuss the implementation and comparison of some threshold proxy signature schemes that are based on the RSA cryptosystem. Comparison is done on the basis of time complexity, space complexity and communication overhead. We compare the performance of four schemes: Hwang et al., Wen et …


A Survey Of Online E-Banking Retail Initiatives, P. Southard, Keng Siau Oct 2004

A Survey Of Online E-Banking Retail Initiatives, P. Southard, Keng Siau

Research Collection School Of Computing and Information Systems

Customer demand is forcing banks to provide their services online. There are two successful paths they can take: to grow, or to specialize in providing localized services and information.


Are Use Case And Class Diagrams Complementary In Requirements Analysis? An Experimental Study On Use Case And Class Diagrams In Uml, Keng Siau, Lihyunn Lee Oct 2004

Are Use Case And Class Diagrams Complementary In Requirements Analysis? An Experimental Study On Use Case And Class Diagrams In Uml, Keng Siau, Lihyunn Lee

Research Collection School Of Computing and Information Systems

Despite the status of united modeling language (UML) as the de facto standard for object oriented modeling, it has received controversial reviews. The most controversial diagram in UML is the use case diagram. Some practitioners claim that use case diagrams are not valuable in requirements analysis and some have even argued that use case diagrams should not be part of UML. This research examined the values of use case diagram in interpreting requirements when use case diagrams are used in conjunction with class diagrams. In other words, the study investigated the possible synergetic values and relationships between the use case …


Informal Animation Sketching: Requirements And Design, Richard C. Davis, James A. Landay Oct 2004

Informal Animation Sketching: Requirements And Design, Richard C. Davis, James A. Landay

Research Collection School Of Computing and Information Systems

We present an interface design for creating informal animations from sketches. Current tools for creating animation are extremely complex. This makes it difficult for designers to prototype animations and nearly impossible for novices to create them at all. Simple animation systems exist but severely restrict the types of motion that can be represented. To guide our design of an animation sketching interface, we conducted field studies into the needs of professional and novice animators. These studies show the wide variety of motions that users desire in informal animations and indicate how to prioritize these types of otion. The interface described …


A Novel Log-Based Relevance Feedback Technique In Content-Based Image Retrieval, Steven C. H. Hoi, Michael R. Lyu Oct 2004

A Novel Log-Based Relevance Feedback Technique In Content-Based Image Retrieval, Steven C. H. Hoi, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Relevance feedback has been proposed as an important technique to boost the retrieval performance in content-based image retrieval (CBIR). However, since there exists a semantic gap between low-level features and high-level semantic concepts in CBIR, typical relevance feedback techniques need to perform a lot of rounds of feedback for achieving satisfactory results. These procedures are time-consuming and may make the users bored in the retrieval tasks. For a long-term study purpose in CBIR, we notice that the users' feedback logs can be available and employed for helping the retrieval tasks in CBIR systems. In this paper, we propose a novel …


Dynamic Access Control For Multi-Privileged Group Communications, Di Ma, Robert H. Deng, Yongdong Wu, Tieyan Li Oct 2004

Dynamic Access Control For Multi-Privileged Group Communications, Di Ma, Robert H. Deng, Yongdong Wu, Tieyan Li

Research Collection School Of Computing and Information Systems

Recently, there is an increase in the number of group communication applications which support multiple service groups of different access privileges. Traditional access control schemes for group applications assume that all the group members have the same access privilege and mostly focus on how to reduce rekeying messages upon user joining and leaving. Relatively little research effort has been spent to address security issues for group communications supporting multiple access privileges. In this paper, we propose a dynamic access control scheme for group communications which support multiple service groups with different access privileges. Our scheme allows dynamic formation of service …


Airconn: A Framework For Tiered Services In Public Wireless Lan Hot Spots, A. Acharya, C. Bisdikian, Archan Misra, Y. Ko Oct 2004

Airconn: A Framework For Tiered Services In Public Wireless Lan Hot Spots, A. Acharya, C. Bisdikian, Archan Misra, Y. Ko

Research Collection School Of Computing and Information Systems

Access to the data services via wireless LANs at private and public hot spot sites is becoming commonplace. The goal of the airConn project is to define an architecture and a prototype implementation that enable the provision of premium and non-premium service tiers for both transient and nontransient users of wireless hot spots. airConn provides for dynamic renegotiation of service tiers and facilitates various billing modes. Thus, it enables service providers to increase their revenue opportunities via multiple flexibility manageable service offerings.


Improving Transliteration With Precise Alignment Of Phoneme Chunks And Using Contextual Features, Wei Gao, Kam-Fai Wong, Wai Lam Oct 2004

Improving Transliteration With Precise Alignment Of Phoneme Chunks And Using Contextual Features, Wei Gao, Kam-Fai Wong, Wai Lam

Research Collection School Of Computing and Information Systems

Automatic transliteration of foreign names is basically regarded as a diminutive clone of the machine translation (MT) problem. It thus follows IBM’s conventional MT models under the sourcechannel framework. Nonetheless, some parameters of this model dealing with zero-fertility words in the target sequences, can negatively impact transliteration effectiveness because of the inevitable inverted conditional probability estimation. Instead of source-channel, this paper presents a direct probabilistic transliteration model using contextual features of phonemes with a tailored alignment scheme for phoneme chunks. Experiments demonstrate superior performance over the source-channel for the task of English-Chinese transliteration.


Indexing And Matching Of Polyphonic Songs For Query-By-Singing System, Tat-Wan Leung, Chong-Wah Ngo Oct 2004

Indexing And Matching Of Polyphonic Songs For Query-By-Singing System, Tat-Wan Leung, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

This paper investigates the issues in polyphonic popular song retrieval. The problems that we consider include singing voice extraction, melodic curve representation, and database indexing. Initially, polyphonic songs are decomposed into singing voices and instruments sounds in both time and frequency domains based on SVM and ICA. The extracted singing voices are represented as two melodic curves that model the statistical mean and neighborhood similarity of notes. To speed up the matching between songs and query, we further adopt proportional transportation distance to index the songs as vantage point trees. Encouraging results have been obtained through experiments.


Deformable Object Model Matching By Topological And Geometric Similarity, Kwok-Leung Tan, Rynson W. H. Lau, Chong-Wah Ngo Oct 2004

Deformable Object Model Matching By Topological And Geometric Similarity, Kwok-Leung Tan, Rynson W. H. Lau, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

In this paper, we present a novel method for efficient 3D model comparison. The method is designed to match highly deformed models through capturing two types of information. First, we propose a feature point extraction algorithm, which is based on “Level Set Diagram”, to reliably capture the topological points of a general 3D model. These topological points represent the skeletal structure of the model. Second, we also capture both spatial and curvature information, which describes the global surface of a 3D model. This is different from traditional topological 3D matching methods that use only low-dimension local features. Our method can …


Blocking Reduction Strategies In Hierarchical Text Classification, Ee Peng Lim, Aixin Sun, Wee-Keong Ng, Jaideep Srivastava Oct 2004

Blocking Reduction Strategies In Hierarchical Text Classification, Ee Peng Lim, Aixin Sun, Wee-Keong Ng, Jaideep Srivastava

Research Collection School Of Computing and Information Systems

One common approach in hierarchical text classification involves associating classifiers with nodes in the category tree and classifying text documents in a top-down manner. Classification methods using this top-down approach can scale well and cope with changes to the category trees. However, all these methods suffer from blocking which refers to documents wrongly rejected by the classifiers at higher-levels and cannot be passed to the classifiers at lower-levels. We propose a classifier-centric performance measure known as blocking factor to determine the extent of the blocking. Three methods are proposed to address the blocking problem, namely, threshold reduction, restricted voting, and …


Compliant Encryption Of Jpeg2000 Codestreams, Yongdong Wu, Robert H. Deng Oct 2004

Compliant Encryption Of Jpeg2000 Codestreams, Yongdong Wu, Robert H. Deng

Research Collection School Of Computing and Information Systems

This paper presents a compliant encryption method for JPEG 2000 codestreams such that the encryption process does not introduce superfluous JPEG2000 markers in the protected codestream, i.e., the protected codestream preserves the syntax of the original codestream. The proposed encryption method works with any standard ciphers, incurs no storage overhead, introduces negligible computational cost and maintains all the desirable properties of the original JPEG 2000 codestream such as error resilience and scalability.