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Computer Science Faculty Research & Creative Works

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Full-Text Articles in Computer Sciences

An Internet Based Intelligent Argumentation System For Collaborative Engineering Design, Xiaoqing Frank Liu, Samir Raorane, Man Zheng, Ming-Chuan Leu Jan 2006

An Internet Based Intelligent Argumentation System For Collaborative Engineering Design, Xiaoqing Frank Liu, Samir Raorane, Man Zheng, Ming-Chuan Leu

Computer Science Faculty Research & Creative Works

Modern product design is a very complicated process which involves groups of designers, manufacturers, suppliers, and customer representatives. Conflicts are unavoidable in collaboration among multiple stakeholders, who have different objectives, requirements, and priorities. Unfortunately, current web-based collaborative engineering design systems do not support collaborative conflict resolution. In this paper, we will develop an intelligent computational argumentation model to enable management of a large scale argumentation network, and resolution of conflicts based on argumentation from many participants. A web-based intelligent argumentation tool is developed as a part of a web-based collaborative engineering design system based on the above model to resolve …


New Graph Model For Channel Assignment In Ad Hoc Wireless Networks, Maggie Xiaoyan Cheng, S. C. Huang, X. Huang, Weili Wu Dec 2005

New Graph Model For Channel Assignment In Ad Hoc Wireless Networks, Maggie Xiaoyan Cheng, S. C. Huang, X. Huang, Weili Wu

Computer Science Faculty Research & Creative Works

The channel assignment problem in ad hoc wireless networks is investigated. The problem is to assign channels to hosts in such a way that interference among hosts is eliminated and the total number of channels is minimised. Interference is caused by direct collisions from hosts that can hear each other or indirect collisions from hosts that cannot hear each other, but simultaneously transmit to the same destination. A new class of disk graphs (FDD: interFerence Double Disk graphs) is proposed that include both kinds of interference edges. Channel assignment in wireless networks is a vertex colouring problem in FDD graphs. …


A Scalable Correlation Aware Aggregation Strategy For Wireless Sensor Networks, Yujie Zhu, Ramanuja Vedantham, Seung Jong Park, Raghupathy Sivakumar Dec 2005

A Scalable Correlation Aware Aggregation Strategy For Wireless Sensor Networks, Yujie Zhu, Ramanuja Vedantham, Seung Jong Park, Raghupathy Sivakumar

Computer Science Faculty Research & Creative Works

Sensors-to-sink data in wireless sensor networks (WSNs) are typically correlated with each other. Exploiting such correlation when performing data aggregation can result in considerable improvements in the bandwidth and energy performance of WSNs. In order to exploit such correlation, we present a scalable and distributed correlation-aware aggregation structure that addresses the practical challenges in the context of aggregation in WSNs. Through simulations and analysis, we evaluate the performance of the proposed approach with centralized and distributed correlation aware and unaware structures.


Location Management In Mobile Ad Hoc Wireless Networks Using Quorums And Clusters, Maggie Xiaoyan Cheng, David H.-C. Du, Ding-Zhu Du Oct 2005

Location Management In Mobile Ad Hoc Wireless Networks Using Quorums And Clusters, Maggie Xiaoyan Cheng, David H.-C. Du, Ding-Zhu Du

Computer Science Faculty Research & Creative Works

Position-based reactive routing is a scalable solution for routing in mobile ad hoc networks. The route discovery algorithm in position-based routing can be efficiently implemented only if the source knows the current address of the destination. In this paper, a quorum-based location management scheme is proposed. Location servers are selected using the minimum dominating set (MDS) approach, and are further organized into quorums for location update and location query. when a mobile node moves, it updates its location servers in the update quorum; when a node requests the location information of another node, it will send a query message to …


The Maximum Flow Algorithm Applied To The Placement And Distributed Steady-State Control Of Upfcs, Austin Armbruster, Bruce M. Mcmillin, Mariesa Crow, Michael R. Gosnell Oct 2005

The Maximum Flow Algorithm Applied To The Placement And Distributed Steady-State Control Of Upfcs, Austin Armbruster, Bruce M. Mcmillin, Mariesa Crow, Michael R. Gosnell

Computer Science Faculty Research & Creative Works

The bulk power system is one of the largest man-made networks and its size makes control an extremely difficult task. This paper presents a method to control a power network using UPFCs set to levels determined by a maximum flow (max-flow) algorithm. The graph-theory-based max-flow is applied to the power system for UPFC placement and scheduling. A distributed version of max-flow is described to coordinate the actions of the UPFCs distributed in a power network. Two sample power systems were tested using max-flow for UPFC placement and settings. The resulting system characteristics are examined over all single-line contingencies and the …


Structured Object-Oriented Co-Analysis/Co-Design Of Hardware/Software For The Facts Powers System, Matt Ryan, Sojan Markose, Xiaoqing Frank Liu, Bruce M. Mcmillin Sep 2005

Structured Object-Oriented Co-Analysis/Co-Design Of Hardware/Software For The Facts Powers System, Matt Ryan, Sojan Markose, Xiaoqing Frank Liu, Bruce M. Mcmillin

Computer Science Faculty Research & Creative Works

There are several approaches to the hardware/software design in embedded systems, ranging from the traditional sequential methods which focus on the determination of the hardware architecture prior to software design, to newer object-oriented approaches that attempt to apply software engineering methods to hardware design without a systematic process. This paper discusses a structured object-oriented methodology for the integrated co-analysis and co-design of hardware/software systems using an extended high order object-oriented modeling technique (HOOMT). This methodology offers a uniform method for hardware and software developers to jointly develop the specifications for and partitioning of the hardware and software components of a …


Sink-To-Sensors Congestion Control, Ramanuja Vedantham, Raghupathy Sivakumar, Seung Jong Park Sep 2005

Sink-To-Sensors Congestion Control, Ramanuja Vedantham, Raghupathy Sivakumar, Seung Jong Park

Computer Science Faculty Research & Creative Works

The problem of congestion in sensor networks is significantly different from conventional ad-hoc networks and has not been studied to any great extent thus far. In this paper, we focus on providing congestion control from the sink to the sensors in a sensor field. We identify the different reasons for congestion from the sink to the sensors and show the uniqueness of the problem in sensor network environments. We propose a scalable, distributed approach that addresses congestion from the sink to the sensors in a sensor network. Through ns2 based simulations, we evaluate the proposed framework, and show that it …


Achieving Minimum Coverage Breach Under Bandwidth Constraints In Wireless Sensor Networks, Maggie Xiaoyan Cheng, Lu Ruan, Weili Wu Aug 2005

Achieving Minimum Coverage Breach Under Bandwidth Constraints In Wireless Sensor Networks, Maggie Xiaoyan Cheng, Lu Ruan, Weili Wu

Computer Science Faculty Research & Creative Works

This paper addresses the coverage breach problem in wireless sensor networks with limited bandwidths. In wireless sensor networks, sensor nodes are powered by batteries. To make efficient use of battery energy is critical to sensor network lifetimes. When targets are redundantly covered by multiple sensors, especially in stochastically deployed sensor networks, it is possible to save battery energy by organizing sensors into mutually exclusive subsets and alternatively activating only one subset at any time. Active nodes are responsible for sensing, computing and communicating. While the coverage of each subset is an important metric for sensor organization, the size of each …


Proving Secure Properties Of Cryptographic Protocols With Knowledge Based Approach, Xiaochun Cheng, Xiaoqi Ma, Maggie Xiaoyan Cheng, Scott C.-H. Huang Jul 2005

Proving Secure Properties Of Cryptographic Protocols With Knowledge Based Approach, Xiaochun Cheng, Xiaoqi Ma, Maggie Xiaoyan Cheng, Scott C.-H. Huang

Computer Science Faculty Research & Creative Works

Cryptographic protocols have been widely used to protect communications over insecure network environments. Existing cryptographic protocols usually contain flaws. To analyze these protocols and find potential flaws in them, the secure properties of them need be studied in depth. This paper attempts to provide a new framework to analyze and prove the secure properties in these protocols. A number of predicates and action functions are used to model the network communication environment. Domain rules are given to describe the transitions of principals' knowledge and belief states. An example of public key authentication protocols has been studied and analysed.


Power Transmission Control Using Distributed Max-Flow, Bruce M. Mcmillin, Austin Armbruster, Mariesa Crow, Michael R. Gosnell Jul 2005

Power Transmission Control Using Distributed Max-Flow, Bruce M. Mcmillin, Austin Armbruster, Mariesa Crow, Michael R. Gosnell

Computer Science Faculty Research & Creative Works

Existing maximum flow algorithms use one processor for all calculations or one processor per vertex in a graph to calculate the maximum possible flow through a graph's vertices. This is not suitable for practical implementation. We extend the max-flow work of Goldberg and Tarjan to a distributed algorithm to calculate maximum flow where the number of processors is less than the number of vertices in a graph. Our algorithm is applied to maximizing electrical flow within a power network where the power grid is modeled as a graph. Error detection measures are included to detect problems in a simulated power …


Energy Balanced Broadcasting Through Delayed Intelligence, Michael R. Gosnell, Ryan Arbarelli, Maggie Xiaoyan Cheng, Bruce M. Mcmillin May 2005

Energy Balanced Broadcasting Through Delayed Intelligence, Michael R. Gosnell, Ryan Arbarelli, Maggie Xiaoyan Cheng, Bruce M. Mcmillin

Computer Science Faculty Research & Creative Works

Ad hoc wireless networks are growing in popularity and usefulness, however they rely on broadcasting as a fundamental process for routing. Improvements to broadcasting have made ad hoc networks more feasible, but sometimes benefit only specific situations. Delayed intelligence (DI) is proposed as a new load balancing approach where small delays are introduced to allow distributed responsibility delegation. Preliminary results show delayed intelligence, when applied in existing broadcasting methods such as passive clustering, can be used to improve the energy disparity and therefore extend ad hoc network lifetime.


Collaborative Global Software Development And Education, Xiaoqing Frank Liu Jan 2005

Collaborative Global Software Development And Education, Xiaoqing Frank Liu

Computer Science Faculty Research & Creative Works

In this position paper, challenges and issues with collaborative global software development and education are discussed. Suggestions are made to improve and strengthen software engineering education to adapt to it.


Consistency Management Among Replicas In Peer-To-Peer Mobile Ad Hoc Networks, Sanjay Kumar Madria, Takahiro Hara Jan 2005

Consistency Management Among Replicas In Peer-To-Peer Mobile Ad Hoc Networks, Sanjay Kumar Madria, Takahiro Hara

Computer Science Faculty Research & Creative Works

Recent advances in wireless communication along with peer-to-peer (P2P) paradigm have led to increasing interest in P2P mobile ad hoc networks. In this paper, we assume an environment where each mobile peer accesses data items held by other peers which are connected by a mobile ad hoc network. Since peers' mobility causes frequent network partitions, replicas of a data item may be inconsistent due to write operations performed by mobile peers. In such an environment, the global consistency of data items is not desirable by many applications. Thus, new consistency maintenance based on local conditions such as location and time …


Adaptive Replication And Access Control Of Multimedia Data In A P2p Environment, Sanjay Kumar Madria, Sanjeev Agarwal Jan 2005

Adaptive Replication And Access Control Of Multimedia Data In A P2p Environment, Sanjay Kumar Madria, Sanjeev Agarwal

Computer Science Faculty Research & Creative Works

This paper explores some of the ideas and solutions related to replication and access control of multimedia data in a hierarchical P2P environment. We provided overview of the techniques to generate multiresolution of multimedia data and explored error recovery and access control issues.


Topology Control Of Ad Hoc Wireless Networks For Energy Efficiency, Maggie Xiaoyan Cheng, Mihaela Cardei, Jinhua Sun, Xiaochun Cheng, Lusheng Wang, Yinfeng Xu, Ding-Zhu Du Dec 2004

Topology Control Of Ad Hoc Wireless Networks For Energy Efficiency, Maggie Xiaoyan Cheng, Mihaela Cardei, Jinhua Sun, Xiaochun Cheng, Lusheng Wang, Yinfeng Xu, Ding-Zhu Du

Computer Science Faculty Research & Creative Works

In ad hoc wireless networks, to compute the transmission power of each wireless node such that the resulting network is connected and the total energy consumption is minimized is defined as a Minimum Energy Network Connectivity (MENC) problem, which is an NP-complete problem. In this paper, we consider the approximated solutions for the MENC problem in ad hoc wireless networks. We present a theorem that reveals the relation between the energy consumption of an optimal solution and that of a spanning tree and propose an optimization algorithm that can improve the result of any spanning tree-based topology. Two polynomial time …


Tcp Performance Over Mobile Ad Hoc Networks: A Quantitative Study, Vaidyanathan Anantharaman, Seung Jong Park, Karthikeyan Sundaresan, Raghupathy Sivakumar Mar 2004

Tcp Performance Over Mobile Ad Hoc Networks: A Quantitative Study, Vaidyanathan Anantharaman, Seung Jong Park, Karthikeyan Sundaresan, Raghupathy Sivakumar

Computer Science Faculty Research & Creative Works

In this paper, we study the performance of the transmission control protocol (TCP) over mobile ad-hoc networks. We present a comprehensive set of simulation results and identify the key factors that impact TCP's performance over ad-hoc networks. We use a variety of parameters including link failure detection latency, route computation latency, packet level route unavailability index, and flow level route unavailability index to capture the impact of mobility. We relate the impact of mobility on the different parameters to TCP's performance by studying the throughput, loss-rate and retransmission timeout values at the TCP layer. We conclude from our results that …


A Scalable Approach For Reliable Downstream Data Delivery In Wireless Sensor Networks, Seung Jong Park, Ramanuja Vedantham, Raghupathy Sivakumar, Ian F. Akyildiz Jan 2004

A Scalable Approach For Reliable Downstream Data Delivery In Wireless Sensor Networks, Seung Jong Park, Ramanuja Vedantham, Raghupathy Sivakumar, Ian F. Akyildiz

Computer Science Faculty Research & Creative Works

There exist several applications of sensor networks where reliability of data delivery can be critical. While the redundancy inherent in a sensor network might increase the degree of reliability, it by no means can provide any guaranteed reliability semantics. In this paper, we consider the problem of reliable sink-to-sensors data delivery. We first identify several fundamental challenges that need to be addressed and are unique to a wireless sensor network environment. We then propose a scalable framework for reliable down-stream data delivery that is specifically designed to both address and leverage the characteristics of a wireless sensor network, while achieving …


Interactive Dna Sequence And Structure Design For Dna Nanotechnology And Dna Computation, Mingjun Zhang, Chaman Sabharwal, Weimin Tao, Tzyh-Jong Tarn, Ning Xi, Guangyong Li Jan 2004

Interactive Dna Sequence And Structure Design For Dna Nanotechnology And Dna Computation, Mingjun Zhang, Chaman Sabharwal, Weimin Tao, Tzyh-Jong Tarn, Ning Xi, Guangyong Li

Computer Science Faculty Research & Creative Works

DNA sequence and structure design are very important for DNA nanotechnology and DNA computation. A computer aided design tool is needed for exploring DNA sequence and structure of interests before experimental synthesis, which is a very time and labor consuming process. In this paper, an interactive DNA sequence and structure design software tool called DNA shop is proposed and implemented.


A Change Impact Dependency Measure For Predicting The Maintainability Of Source Code, Xiaoqing Frank Liu Jan 2004

A Change Impact Dependency Measure For Predicting The Maintainability Of Source Code, Xiaoqing Frank Liu

Computer Science Faculty Research & Creative Works

We first articulate the theoretic difficulties with the existing metrics designed for predicting software maintainability. To overcome the difficulties, we propose to measure a purely internal and objective attribute of code, namely change impact dependency, and show how it can be modeled to predict real change impact. The proposed base measure can be further elaborated for evaluating software maintainability.


Micro Spies, Georae W. Zobrist Jan 2004

Micro Spies, Georae W. Zobrist

Computer Science Faculty Research & Creative Works

No abstract provided.


Biup3: Boundary Topological Invariant Of 3d Objects Through Front Propagation At A Constant Speed, Xiaoqing Frank Liu Jan 2004

Biup3: Boundary Topological Invariant Of 3d Objects Through Front Propagation At A Constant Speed, Xiaoqing Frank Liu

Computer Science Faculty Research & Creative Works

Topological features constitute the highest abstraction in object representation. Euler characteristic is one of the most widely used topological invariants. The computation of the Euler characteristic is mainly based on three well-known mathematical formulae, which calculate either on the boundary of object or on the whole object. However, as digital objects are often non-manifolds, none of the known formulae can correctly compute the genus of digital surfaces. In this paper, we show that a new topological surface invariant of 3D digital objects, called BIUP/sup 3/, can be obtained through a special homeomorphic transform: front propagation at a constant speed. BIUP/sup …


A Generic Oo Architecture Language For Semantics Analysis Of Oo Specification, Xiaoqing Frank Liu Jan 2004

A Generic Oo Architecture Language For Semantics Analysis Of Oo Specification, Xiaoqing Frank Liu

Computer Science Faculty Research & Creative Works

Formal specification enables a rigorous analysis and model checking for ensuring the correctness of specification. Formal OO specification methods are of mathematical nature and the semantics of specification is purposely defined such that it is not related to the semantics of code. We propose a new language, which will lay a common semantics ground for both specification and code.


Interactive Dna Sequence And Structure Design For Dna Nanoapplications, Mingjun Zhang, Chaman Sabharwal, Weimin Tao, Tzyh-Jong Tarn, Ning Xi, Guangyong Li Jan 2004

Interactive Dna Sequence And Structure Design For Dna Nanoapplications, Mingjun Zhang, Chaman Sabharwal, Weimin Tao, Tzyh-Jong Tarn, Ning Xi, Guangyong Li

Computer Science Faculty Research & Creative Works

DNA sequence and structure design is very important for DNA nanoapplications. A computer-aided design tool is needed for exploring DNA sequence and structure of interests before experimental synthesis, which is a time- and labor-consuming process. In this paper, an interactive DNA sequence and structure design software tool called DNA shop is proposed and implemented. The visualization tool can generate DNA structures by specifying, selecting, and moving DNA sequences around and display corresponding structures. Using the tool, DNA sequence and structure can be visually inspected in three-dimensional space before experimental studies.


Priority Assessment Of Software Requirements From Multiple Perspectives, Xiaoqing Frank Liu, Chandra Sekhar Veera, Yan Sun, Kunio Noguchi, Yuji Kyoya Jan 2004

Priority Assessment Of Software Requirements From Multiple Perspectives, Xiaoqing Frank Liu, Chandra Sekhar Veera, Yan Sun, Kunio Noguchi, Yuji Kyoya

Computer Science Faculty Research & Creative Works

The development of complex software systems involves collecting software requirements from various stakeholders. Often stakeholder perceptions conflict during the requirements elicitation phase. An effective technique to resolve such a conflict is needed. We presented a framework that prioritizes software requirements gathered from multiple stakeholders by incorporating inter-perspective relationships, which is not addressed by existing priority assessment techniques. We use a relationship matrix to analyze the impact between requirements and facilitate the integration process which assesses their priorities based on their relationships from multiple perspectives. It allows the development team to resolve conflicts effectively and concentrate their valuable time and resources …


Sensor Networks: An Overview, Malik Tubaishat, Sanjay Kumar Madria Jan 2003

Sensor Networks: An Overview, Malik Tubaishat, Sanjay Kumar Madria

Computer Science Faculty Research & Creative Works

Advances in hardware and wireless network technologies have created low-cost, low-power, multifunctional miniature sensor devices. These devices make up hundreds or thousands of ad hoc tiny sensor nodes spread across a geographical area. These sensor nodes collaborate among themselves to establish a sensing network. A sensor network can provide access to information anytime, anywhere by collecting, processing, analyzing and disseminating data. Thus, the network actively participates in creating a smart environment.


Detecting And Representing Relevant Web Deltas In Whoweda, Sanjay Kumar Madria, Wee Keong Ng, Sourav S. Bhowmick Jan 2003

Detecting And Representing Relevant Web Deltas In Whoweda, Sanjay Kumar Madria, Wee Keong Ng, Sourav S. Bhowmick

Computer Science Faculty Research & Creative Works

In this paper, we present a mechanism for detecting and representing changes, given the old and new versions of a set of interlinked Web documents, retrieved in response to a user''s query. In particular, we show how to detect and represent Web deltas, i.e., changes in the Web documents that are relevant to a user''s query in the context of our Web warehousing system called WHOWEDA (Warehouse of Web Data). In WHOWEDA, Web information is materialized views stored in Web tables in the form of Web tuples. These Web tuples, represented as directed graphs, can be manipulated using a set …


Two Distributed Algorithms For E-Ticket Validation Protocols For Mobile Clients, H. Mohanty, Sanjay Kumar Madria, T. Suman Kumar Reddy, R. K. Ghosh Jan 2003

Two Distributed Algorithms For E-Ticket Validation Protocols For Mobile Clients, H. Mohanty, Sanjay Kumar Madria, T. Suman Kumar Reddy, R. K. Ghosh

Computer Science Faculty Research & Creative Works

The e-ticket (electronic ticket) validation problem has relevance in mobile computing environment because of the multiple submission of a ticket that is possible due to intermittent disconnections and mobility of hosts. Here, we propose protocols that are not only sensitive to disconnection but also to location. One of the proposed protocols is the variant of the distributed protocol proposed by Pedone (2000) for Internet users. This shows that a distributed protocol for static network can be restructured for distributed computation in a mobile computing environment. We have also proposed another protocol that uses a hierarchical location database of mobile hosts …


Representation Of Web Data In A Web Warehouse, Sourav S. Bhowmick, Sanjay Madria, Wee Keong Ng Jan 2003

Representation Of Web Data In A Web Warehouse, Sourav S. Bhowmick, Sanjay Madria, Wee Keong Ng

Computer Science Faculty Research & Creative Works

We believe that, to manage Web data effectively, there is a need to build a data warehouse of Web data, i.e. a Web warehouse. in this paper, we focus on how to represent and store relevant hyperlinked Web documents effectively in a Web warehouse called WHOWEDA (WareHouse of WEb DAta) for further querying and manipulation. We present a simple and general model for representing metadata, structure and content of Web documents and hyperlinks in WHOWEDA. We discuss node and link objects which are used to represent Web documents and hyperlinks respectively in WHOWEDA. These objects are first class objects in …


An Intelligent Early Warning System For Software Quality Improvement And Project Management, Xiaoqing Frank Liu, Gautam Kane, Monu Bambroo Jan 2003

An Intelligent Early Warning System For Software Quality Improvement And Project Management, Xiaoqing Frank Liu, Gautam Kane, Monu Bambroo

Computer Science Faculty Research & Creative Works

One of the main reasons behind unfruitful software development projects is that it is often too late to correct the problems by the time they are detected. It clearly indicates the need for early warning about the potential risks. In this paper, we discuss an intelligent software early warning system based on fuzzy logic using an integrated set of software metrics. It helps to assess risks associated with being behind schedule, over budget, and poor quality in software development and maintenance from multiple perspectives. It handles incomplete, inaccurate, and imprecise information, and resolve conflicts in an uncertain environment in its …


Load-Sensitive Transmission Power Control In Wireless Ad-Hoc Networks, Seung Jong Park, Raghupathy Sivakumar Dec 2002

Load-Sensitive Transmission Power Control In Wireless Ad-Hoc Networks, Seung Jong Park, Raghupathy Sivakumar

Computer Science Faculty Research & Creative Works

Transmission power control in ad-hoc networks has hitherto been used only for achieving connectivity of networks. It has been implicitly assumed that the optimal throughput performance in ad-hoc networks can be achieved when using the minimum transmission power required to keep the network connected. However, in this paper we argue that such an assumption remains valid only under high node densities, which is not the characteristic of typical ad-hoc networks. Using both throughput and throughput per unit energy as the optimization criteria, we demonstrate that the optimal transmission power depends on several network characteristics such as the number of stations, …