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Research Collection School Of Computing and Information Systems

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Articles 91 - 120 of 123

Full-Text Articles in Digital Communications and Networking

Energy-Efficient Continuous Activity Recognition On Mobile Phones: An Activity-Adaptive Approach, Zhixian Yan, Vigneshwaran Subbaraju, Dipanjan Chakraborty, Archan Misra, Karl Aberer Jun 2012

Energy-Efficient Continuous Activity Recognition On Mobile Phones: An Activity-Adaptive Approach, Zhixian Yan, Vigneshwaran Subbaraju, Dipanjan Chakraborty, Archan Misra, Karl Aberer

Research Collection School Of Computing and Information Systems

Power consumption on mobile phones is a painful obstacle towards adoption of continuous sensing driven applications, e.g., continuously inferring individual’s locomotive activities (such as ‘sit’, ‘stand’ or ‘walk’) using the embedded accelerometer sensor. To reduce the energy overhead of such continuous activity sensing, we first investigate how the choice of accelerometer sampling frequency & classification features affects, separately for each activity, the “energy overhead” vs. “classification accuracy” tradeoff. We find that such tradeoff is activity specific. Based on this finding, we introduce an activity-sensitive strategy (dubbed “A3R” – Adaptive Accelerometer-based Activity Recognition) for continuous activity recognition, where the choice of …


Spatial Queries In Wireless Broadcast Environments [Keynote Speech], Kyriakos Mouratidis May 2012

Spatial Queries In Wireless Broadcast Environments [Keynote Speech], Kyriakos Mouratidis

Research Collection School Of Computing and Information Systems

Wireless data broadcasting is a promising technique for information dissemination that exploits the computational capabilities of mobile devices, in order to enhance the scalability of the system. Under this environment, the data are continuously broadcast by the server, interleaved with some indexing information for query processing. Clients may tune in the broadcast channel and process their queries locally without contacting the server. In this paper we focus on spatial queries in particular. First, we review existing methods on this topic. Next, taking shortest path computation as an example, we showcase technical challenges arising in this processing model and describe techniques …


On Limitations Of Designing Usable Leakage-Resilient Password Systems: Attacks, Principles And Usability, Qiang Yan, Jin Han, Yingjiu Li, Huijie, Robert Deng Feb 2012

On Limitations Of Designing Usable Leakage-Resilient Password Systems: Attacks, Principles And Usability, Qiang Yan, Jin Han, Yingjiu Li, Huijie, Robert Deng

Research Collection School Of Computing and Information Systems

The design of leakage-resilient password systems (LRPSes) in the absence of trusted devices remains a challenging problem today despite two decades of intensive research in the security community. In this paper, we investigate the inherent tradeoff between security and usability in designing LRPS. First, we demonstrate that most of the existing LRPS systems are subject to two types of generic attacks - brute force and statistical attacks, whose power has been underestimated in the literature. Second, in order to defend against these two generic attacks, we introduce five design principles that are necessary to achieve leakage resilience in the absence …


Towards Fine-Grained Radio-Based Indoor Location, Jie Xiong, Kyle Jamieson Feb 2012

Towards Fine-Grained Radio-Based Indoor Location, Jie Xiong, Kyle Jamieson

Research Collection School Of Computing and Information Systems

Location systems are key to a rich experience for mobile users. When they roam outdoors, mobiles can usually count on a clear GPS signal for an accurate location, but indoors, GPS usually fades, and so up until recently, mobiles have had to rely mainly on rather coarse-grained signal strength readings for location. What has changed this status quo is the recent trend of dramatically increasing numbers of antennas at the indoor AP, mainly to bolster capacity and coverage with multiple-input, multiple-output (MIMO) techniques. In the near future, the number of antennas at the access point will increase several-fold, to meet …


Guest Editorial: Special Issue On Game Theory In Communication Networks, Tansu Alpcan, Rachid El-Azouzi, Nahum Shimkin, Laura Wynter Jun 2011

Guest Editorial: Special Issue On Game Theory In Communication Networks, Tansu Alpcan, Rachid El-Azouzi, Nahum Shimkin, Laura Wynter

Research Collection School Of Computing and Information Systems

The distributed nature of wireline and wireless communication networks gives rise to many challenges in their analysis, control, and management. Development of decentralized control mechanisms that achieve fair allocation of system resources despite the selfish nature of the users is among the major issues in networks research. Consequently, game theoretic methods and approaches have been increasingly utilized to gain a deeper analytical understanding of these complex problems and systems.


A High-Throughput Routing Metric For Reliable Multicast In Multi-Rate Wireless Mesh Networks, Xin Zhao, Jun Guo, Chun Tung Chou, Archan Misra, Sanjay Jha Apr 2011

A High-Throughput Routing Metric For Reliable Multicast In Multi-Rate Wireless Mesh Networks, Xin Zhao, Jun Guo, Chun Tung Chou, Archan Misra, Sanjay Jha

Research Collection School Of Computing and Information Systems

We propose a routing metric for enabling highthroughput reliable multicast in multi-rate wireless mesh networks. This new multicast routing metric, called expected multicast transmission time (EMTT), captures the combined effects of 1) MAC-layer retransmission-based reliability, 2) transmission rate diversity, 3) wireless broadcast advantage, and 4) link quality awareness. The EMTT of one-hop transmission of a multicast packet minimizes the amount of expected transmission time (including that required for retransmissions). This is achieved by allowing the sender to adapt its bit-rate for each ongoing transmission/retransmission, optimized exclusively for its nexthop receivers that have not yet received the multicast packet. We model …


Pgtp: Power Aware Game Transport Protocol For Multi-Player Mobile Games, Bhojan Anand, Jeena Sebastian, Soh Yu Ming, Akhihebbal L. Ananda, Mun Choon Chan, Rajesh Krishna Balan Feb 2011

Pgtp: Power Aware Game Transport Protocol For Multi-Player Mobile Games, Bhojan Anand, Jeena Sebastian, Soh Yu Ming, Akhihebbal L. Ananda, Mun Choon Chan, Rajesh Krishna Balan

Research Collection School Of Computing and Information Systems

Applications on the smartphones are able to capitalize on the increasingly advanced hardware to provide a user experience reasonably impressive. However, the advancement of these applications are hindered battery lifetime of the smartphones. The battery technologies have a relatively low growth rate. Applications like mobile multiplayer games are especially power hungry as they maximize the use of the network, display and CPU resources. The PGTP, presented in this paper is aware of both the transport requirement of these multiplayer mobile games and the limitation posed by battery resource. PGTP dynamically controls the transport based on the criticality of game state …


Enhancing Brand Equity Through Flow: Comparison Of 2d Versus 3d Virtual World, Fiona Fui-Hoon Nah, Brenda Eschenbrenner, David Dewester Dec 2010

Enhancing Brand Equity Through Flow: Comparison Of 2d Versus 3d Virtual World, Fiona Fui-Hoon Nah, Brenda Eschenbrenner, David Dewester

Research Collection School Of Computing and Information Systems

This research uses the theory of flow to examine the effect of 2D versus 3D virtual world environments on brand equity and use intention. The results suggest that a 3D virtual world environment has both positive (indirect) and negative (direct) effects on brand equity. The positive, indirect effect of the 3D virtual world environment occurs through feelings of telepresence and enjoyment, both of which contribute positively to brand equity and, in turn, induces a higher behavioral intention. The negative, direct effect can be explained using distraction-conflict theory, where attentional conflict is faced by users of a highly interactive and rich …


Effects Of National Culture On Types Of Knowledge Sharing In Virtual Communities, Keng Siau, J. Erickson, Fiona Fui-Hoon Nah Oct 2010

Effects Of National Culture On Types Of Knowledge Sharing In Virtual Communities, Keng Siau, J. Erickson, Fiona Fui-Hoon Nah

Research Collection School Of Computing and Information Systems

Organizations are using virtual communities to facilitate knowledge management and to enhance communication among employees, customers, and other interested individuals. Individual users can use virtual communities to engage in knowledge sharing. Professional communicators need to understand and adapt to a globalized and “flat” world, where people across different cultures interact freely and easily with one another in virtual communities. An intriguing question regarding virtual communities relates to whether national culture affects communication and types of knowledge sharing. This study examines the influence of US and Chinese national cultures on types of knowledge-sharing activities in virtual communities. The findings indicate that …


Co-Creation And Collaboration In A Virtual World: A 3d Visualization Design Project In Second Life, Keng Siau, Fiona Fui-Hoon Nah, B. Mennecke, S. Schiller Oct 2010

Co-Creation And Collaboration In A Virtual World: A 3d Visualization Design Project In Second Life, Keng Siau, Fiona Fui-Hoon Nah, B. Mennecke, S. Schiller

Research Collection School Of Computing and Information Systems

One of the most successful and useful implementations of 3D virtual worlds is in the area of education and training. This paper discusses the use of virtual worlds in education and describes an innovative 3D visualization design project using one of the most popular virtual worlds, Second Life. This ongoing project is a partnership between IBM and three universities in the United States: the University of Nebraska-Lincoln, Iowa State University, and Wright State University. More than 400 MBA students have participated in this project by completing a creative design project that involves co-creation and collaboration in Second Life. The MBA …


Open Innovation In Platform Competition, Mei Lin May 2010

Open Innovation In Platform Competition, Mei Lin

Research Collection School Of Computing and Information Systems

We examine the competition between a proprietary platform and an open platform,where each platform holds a two-sided market consisted of app developers and users.The open platform cultivates an innovative environment by inviting public efforts todevelop the platform itself and permitting distribution of apps outside of its own appmarket; the proprietary platform restricts apps sales solely within its app market. Weuse a game theoretic model to capture this competitive phenomenon and analyze theimpact of growth of the open source community on the platform competition. We foundthat growth of the open community mitigates the platform rivalry, and balances the developernetwork sizes on …


Continuous Spatial Assignment Of Moving Users, Hou U Leong, Kyriakos Mouratidis, Nikos Mamoulis Apr 2010

Continuous Spatial Assignment Of Moving Users, Hou U Leong, Kyriakos Mouratidis, Nikos Mamoulis

Research Collection School Of Computing and Information Systems

Consider a set of servers and a set of users, where each server has a coverage region (i.e., an area of service) and a capacity (i.e., a maximum number of users it can serve). Our task is to assign every user to one server subject to the coverage and capacity constraints. To offer the highest quality of service, we wish to minimize the average distance between users and their assigned server. This is an instance of a well-studied problem in operations research, termed optimal assignment. Even though there exist several solutions for the static case (where user locations are fixed), …


Managing Media Rich Geo-Spatial Annotations For A Map-Based Mobile Application Using Clustering, Khasfariyati Razikin, Dion Hoe-Lian Goh, Ee Peng Lim, Aixin Sun, Yin-Leng Theng, Thi Nhu Quynh Kim, Kalyani Chatterjea, Chew-Hung Chang Apr 2010

Managing Media Rich Geo-Spatial Annotations For A Map-Based Mobile Application Using Clustering, Khasfariyati Razikin, Dion Hoe-Lian Goh, Ee Peng Lim, Aixin Sun, Yin-Leng Theng, Thi Nhu Quynh Kim, Kalyani Chatterjea, Chew-Hung Chang

Research Collection School Of Computing and Information Systems

With the prevalence of mobile devices that are equipped with wireless Internet capabilities and Global Positioning System (GPS) functionality, the creation and access of user-generated content are extended to users on the go. Such content are tied to real world objects, in the form of geospatial annotations, and it is only natural that these annotations are visualized using a map-based approach. However, viewing maps that are filled with annotations could hinder the serendipitous discovery of data, especially on the small screens of mobile devices. This calls for a need to manage the annotations. In this paper, we introduce a mobile …


Searching Blogs And News: A Study On Popular Queries, Aixin Sun, Meishan Hu, Ee Peng Lim Jul 2008

Searching Blogs And News: A Study On Popular Queries, Aixin Sun, Meishan Hu, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Blog/news search engines are very important channels to reach information about the real-time happenings. In this paper, we study the popular queries collected over one year period and compare their search results returned by a blog search engine (i.e., Technorati) and a news search engine (i.e., Google News). We observed that the numbers of hits returned by the two search engines for the same set of queries were highly correlated, suggesting that blogs often provide commentary to current events reported in news. As many popular queries are related to some events, we further observed a high cohesiveness among the returned …


Insults In Your Inbox, M. Thulasidas Sep 2007

Insults In Your Inbox, M. Thulasidas

Research Collection School Of Computing and Information Systems

Email is a boon at work, but aggressive staff may use it to inflict humiliation. Most of its impact has been positive. An email from the big boss to all@yourcompany, for instance, is a fair substitute for a general communication meet- ing. In smaller teams, email often saves meetings and increases productivity.


Maximizing Broadcast And Multicast Traffic Load Through Link-Rate Diversity In Wireless Mesh Networks, Chun Tung Chou, Bao Hua Liu, Archan Misra Jun 2007

Maximizing Broadcast And Multicast Traffic Load Through Link-Rate Diversity In Wireless Mesh Networks, Chun Tung Chou, Bao Hua Liu, Archan Misra

Research Collection School Of Computing and Information Systems

This paper studies some of the fundamental challenges and opportunities associated with the network-layer broadcast and multicast in a multihop multirate wireless mesh network (WMN). In particular, we focus on exploiting the ability of nodes to perform link-layer broadcasts at different rates (with correspondingly different coverage areas). We first show how, in the broadcast wireless medium, the available capacity at a mesh node for a multicast transmission is not just a function of the aggregate pre-existing traffic load of other interfering nodes, but intricately coupled to the actual (sender, receiver) set and the link-layer rate of each individual transmission. We …


Social Network Structures In Open Source Software Development Teams, Y. Long, Keng Siau Apr 2007

Social Network Structures In Open Source Software Development Teams, Y. Long, Keng Siau

Research Collection School Of Computing and Information Systems

Drawing on social network theories and previous studies, this research examines the dynamics of social network structures in open source software (OSS) teams. Three projects were selected from SourceForge.net in terms of their similarities as well as their differences. Monthly data were extracted from the bug tracking systems in order to achieve a longitudinal view of the interaction pattern of each project. Social network analysis was used to generate the indices of social structure. The finding suggests that the interaction pattern of OSS projects evolves from a single hub at the beginning to a corel periphery model as the projects …


Introduction: Special Issue For The Selected Papers In The Fourth International Conference On Intelligent Multimedia Computing And Networking (Immcn) 2005, Chong-Wah Ngo, Hong-Va Leong Jan 2007

Introduction: Special Issue For The Selected Papers In The Fourth International Conference On Intelligent Multimedia Computing And Networking (Immcn) 2005, Chong-Wah Ngo, Hong-Va Leong

Research Collection School Of Computing and Information Systems

This special issue introduces seven papers selected from the IMMCN’ 2005, covering a wide range of emerging topics in multimedia field. These papers receive high scores and good comments from the reviewers in their respective areas of intelligent and nextgeneration networking, technology and application, multimedia coding, content analysis and retrieval. The seven papers are extended to 20 pages and then gone through another review process before the final publication. In this issue, we have two papers for video streaming, two papers for multimedia applications, one paper for video coding, and two papers for image and video retrieval.


A Survey On Networking Games In Telecommunications, E. Altman, T. Boulogne, R. El-Azouzi, T. Jiménez, Laura Wynter Jan 2006

A Survey On Networking Games In Telecommunications, E. Altman, T. Boulogne, R. El-Azouzi, T. Jiménez, Laura Wynter

Research Collection School Of Computing and Information Systems

In this survey, we summarize different modeling and solution concepts of networking games, as well as a number of different applications in telecommunications that make use of or can make use of networking games. We identify some of the mathematical challenges and methodologies that are involved in these problems. We include here work that has relevance to networking games in telecommunications from other areas, in particular from transportation planning.


Synthesizing E-Government Stage Models – A Meta-Synthesis Based On Meta-Ethnography Approach, Keng Siau, Y. Long May 2005

Synthesizing E-Government Stage Models – A Meta-Synthesis Based On Meta-Ethnography Approach, Keng Siau, Y. Long

Research Collection School Of Computing and Information Systems

The growing interest in e-government raises the question of stages in e-government development. A few stage models for e-government have been proposed. Without a common e-government stage model, different research in e-government may be based on different stage models. This presents a difficulty in comparing and understanding different research results. In this research, we synthesize the existing e-government stage models so that there is a common frame of reference for researchers and practitioners in the area.


Synthesizing E-Government Stage Models – A Meta-Synthesis Based On Meta-Ethnography Approach, Keng Siau, Y. Long May 2005

Synthesizing E-Government Stage Models – A Meta-Synthesis Based On Meta-Ethnography Approach, Keng Siau, Y. Long

Research Collection School Of Computing and Information Systems

The growing interest in e-government raises the question of stages in e-government development. A few stage models for e-government have been proposed. Without a common e-government stage model, different research in e-government may be based on different stage models. This presents a difficulty in comparing and understanding different research results. In this research, we synthesize the existing e-government stage models so that there is a common frame of reference for researchers and practitioners in the area.


The Value Of Mobile Applications: A Utility Company Study, Fiona Fui-Hoon Nah, Keng Siau, Hong Sheng Feb 2005

The Value Of Mobile Applications: A Utility Company Study, Fiona Fui-Hoon Nah, Keng Siau, Hong Sheng

Research Collection School Of Computing and Information Systems

The value proposition of mobile applications i.e. the net value of the benefits and costs associated with the adoption and adaptation of mobile applications is discussed. A means-ends network that depicts the fundamental relationships among the objectives such as efficiency, effectiveness, customer satisfaction, security, cost, and employee acceptance, was developed. The network is useful to researchers as it highlights the issues, concerns, and values of mobile applications. The network help the managers and practitioners to achieve their companies' objectives of implementing mobile and wireless applications.


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.


Optimizing Proportionally Fair Prices, Laura Wynter Sep 2004

Optimizing Proportionally Fair Prices, Laura Wynter

Research Collection School Of Computing and Information Systems

We demonstrate the non-uniqueness of proportional fairness prices, and show that the model of Kelly et al. [9] falls into the category of models that can be generalized to allow optimization of the link prices, with a view toward profit maximization. However, through this framework, we also show that the total revenue that can be obtained through proportional fairness pricing on a network is unique.


Stochastic Analysis And Performance Evaluation Of Wireless Schedulers, R. Rom, Hwee-Pink Tan Feb 2004

Stochastic Analysis And Performance Evaluation Of Wireless Schedulers, R. Rom, Hwee-Pink Tan

Research Collection School Of Computing and Information Systems

In the last few years, wireless scheduling algorithms have been proposed by supplementing wireline scheduling algorithms with a wireless adaptation scheme. However, Quality of Service (QoS) bounds have either been derived for flows that perceive error-free conditions or a static worst-case channel condition. Such an assumption of the channel condition is unrealistic, since channel errors are known to be bursty in nature. Hence, these bounds are inadequate to characterize the scheduler's QoS performance. Our research focuses on performing an extensive analysis of wireless scheduling in order to derive statistical QoS performance bounds under realistic channel conditions. In this paper, we …


A New Look At The Multiclass Network Equilibrium Problem, Patrice Marcotte, Laura Wynter Jan 2004

A New Look At The Multiclass Network Equilibrium Problem, Patrice Marcotte, Laura Wynter

Research Collection School Of Computing and Information Systems

The multiclass network equilibrium problem is expressed in general as a nonmonotone, asymmetric, variational inequality problem. We show that in spite of the nonmonotonicity of the cost operator, the problem may actually satisfy a weaker property, induced by the hierarchical nature of the travel cost interactions. This property allows a natural decomposition approach, not otherwise available, that admits provably convergent algorithms. We present one such algorithm, easily implementable using a solver for the single-class network equilibrium problem, together with a convergence proof.


A Fit-Gap Analysis Of E-Business Curricula Vs. Industry Need, S. Davis, Keng Siau, K. Dhenuvakonda Dec 2003

A Fit-Gap Analysis Of E-Business Curricula Vs. Industry Need, S. Davis, Keng Siau, K. Dhenuvakonda

Research Collection School Of Computing and Information Systems

The alignment of e-business academic programs with the e-business market is examined using a fit-gap analysis. Two high-end business schools, ranked independently by US News and Business Week, were chosen as sample. A total of 391 different e-commerce courses were identified, which were classified into 24 categories. Out of these, there are two broad and distinct tracks in e-business curricula, with one track paving the way for an e-business career with a prevailing focus on the business aspect and the other track leading to a career focusing on technology and Web-based systems development. Industry demand for e-business professionals and the …


Creating A Virtual Store Image, P. Katerattanakul, Keng Siau Dec 2003

Creating A Virtual Store Image, P. Katerattanakul, Keng Siau

Research Collection School Of Computing and Information Systems

A study was conducted to describe some of the factors that needed to be considered for a virtual store. It was revealed that the growth of e-commerce and online businesses has made it essential to understand the critical attributes of image for a virtual store. Store image was described as the way in which the store was defined by customers and several studies. The study compiled 77 designs and features into a list used to construct a survey. Four hundred and twenty-seven potential customers were requested to rate the significance of each item on the list. The information gathered identified …


Building Customer Trust In Mobile Commerce, Keng Siau, Zixing Shen Apr 2003

Building Customer Trust In Mobile Commerce, Keng Siau, Zixing Shen

Research Collection School Of Computing and Information Systems

Customer trust, which is crucial for the growth and success of mobile commerce, is discussed. Building customer trust is a complex process that involves technology and business practices as well as movement from initial trust formation to continuous trust development. Gaining customer trust involves consideration of its three components: competence trust, predictability trust and goodwill trust. From a customer's perspective, competence trust in e-commerce is built upon the Internet vendor's skills, expertise and operational abilities.


Enterprise Integration With Erp And Eai, Jinyoul Lee, Keng Siau, Soongoo Hong Feb 2003

Enterprise Integration With Erp And Eai, Jinyoul Lee, Keng Siau, Soongoo Hong

Research Collection School Of Computing and Information Systems

The Integration of enterprise with the ERP (enterprise resource planning) and EAI (enterprise application integration) is discussed. The ERP supports the centralized business strategy while EAI accomodates the decentralized business processes. The changes brought in by the internet technology led the internalization and extrenalization to move together. The agility and the flexibility in the organizations would be achieved by a greater degree of communication, coordination and cooperation in human factors and information technologies. The enterprise integration fulfills the needs of both internal business processes and external customer by internalization and externalization.