Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 9 of 9

Full-Text Articles in Physical Sciences and Mathematics

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 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.


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.


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.


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 …


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 …


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.


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 …