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Computer Engineering Commons

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2008

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Articles 511 - 522 of 522

Full-Text Articles in Computer Engineering

A Summary Of Recent Developments On Metamaterial-Based And Metamaterial-Inspired Efficient Electrically Small Antennas, Aycan Erentok, Richard W. Ziolkowski Jan 2008

A Summary Of Recent Developments On Metamaterial-Based And Metamaterial-Inspired Efficient Electrically Small Antennas, Aycan Erentok, Richard W. Ziolkowski

Turkish Journal of Electrical Engineering and Computer Sciences

This paper summarizes our recent research efforts to realize efficient electrically small antenna (EESA) systems based on ideal analytical and numerical metamaterial-based antenna systems, and physically realized metamaterial-inspired antenna designs. Our theoretical and numerical studies of the radiation and resonance behaviors of the proposed metamaterial-based EESA systems, as well as our efforts to conceptualize structures which might be used to build them, have led to the discovery of several realizable metamaterial-inspired EESA systems. The measurement results confirm the numerical performance predictions.


Dual-Band Split-Ring Antenna Design For Wlan Applications, S. Cumhur Başaran, Yunus E. Erdemli̇ Jan 2008

Dual-Band Split-Ring Antenna Design For Wlan Applications, S. Cumhur Başaran, Yunus E. Erdemli̇

Turkish Journal of Electrical Engineering and Computer Sciences

A dual-band microstrip antenna based on split-ring elements is introduced for WLAN (2.4/5.2 GHz) applications. The proposed split-ring antenna (SRA) has a compact novel design which provides about 2% impedance-bandwidth without a need for additional matching network. Analysis and design of the proposed microstrip antenna is carried out by means of full-wave simulators based on the finite-element method.


Overview Of Biocreative Ii Gene Mention Recognition, Larry Smith, Lorraine K. Tanabe, Rie Johnson Nee Ando, Cheng-Ju Kuo, I-Fang Chung, Chun-Nan Hsu, Yu-Shi Lin, Roman Klinger, Christoph M. Friedrich, Kuzman Ganchev, Manabu Torii, Hongfang Liu, Barry Haddow, Craig A. Struble, Richard J. Povinelli, Andreas Vlachos, William A. Baumgartner, Lawrence Hunter, Bob Carpenter, Richard Tzong-Han Tsai, Hong-Jie Dai, Feng Liu, Yifei Chen, Chengjie Sun, Sophia Katrenko, Pieter Adriaans, Christian Blaschke, Rafael Torres, Mariana Neves, Preslav Nakov, Anna Divoli, Manuel Maña-López, Jacinto Mata, W John Wilbur Jan 2008

Overview Of Biocreative Ii Gene Mention Recognition, Larry Smith, Lorraine K. Tanabe, Rie Johnson Nee Ando, Cheng-Ju Kuo, I-Fang Chung, Chun-Nan Hsu, Yu-Shi Lin, Roman Klinger, Christoph M. Friedrich, Kuzman Ganchev, Manabu Torii, Hongfang Liu, Barry Haddow, Craig A. Struble, Richard J. Povinelli, Andreas Vlachos, William A. Baumgartner, Lawrence Hunter, Bob Carpenter, Richard Tzong-Han Tsai, Hong-Jie Dai, Feng Liu, Yifei Chen, Chengjie Sun, Sophia Katrenko, Pieter Adriaans, Christian Blaschke, Rafael Torres, Mariana Neves, Preslav Nakov, Anna Divoli, Manuel Maña-López, Jacinto Mata, W John Wilbur

Electrical and Computer Engineering Faculty Research and Publications

Nineteen teams presented results for the Gene Mention Task at the BioCreative II Workshop. In this task participants designed systems to identify substrings in sentences corresponding to gene name mentions. A variety of different methods were used and the results varied with a highest achieved F1 score of 0.8721. Here we present brief descriptions of all the methods used and a statistical analysis of the results. We also demonstrate that, by combining the results from all submissions, an F score of 0.9066 is feasible, and furthermore that the best result makes use of the lowest scoring submissions.


Analysis Of Information Remaining On Hand Held Devices For Sale On The Second Hand Market, Andrew Jones, Craig Valli, Iain Sutherland Jan 2008

Analysis Of Information Remaining On Hand Held Devices For Sale On The Second Hand Market, Andrew Jones, Craig Valli, Iain Sutherland

Research outputs pre 2011

The ownership and use of mobile phones, Personal Digital Assistants and other hand held devices is now ubiquitous both for home and business use. The majority of these devices have a high initial cost, a relatively short period before they become obsolescent and a relatively low second hand value. As a result of this, when the devices are replaced, there are indications that they tend to be discarded. As technology has continued to develop, it has led to an increasing diversity in the number and type of devices that are available, and the processing power and the storage capacity of …


Source Localisation In Wireless Sensor Networks Based On Optimised Maximum Likelihood, Mohammed Rahman, Daryoush Habibi, Iftekhar Ahmad Jan 2008

Source Localisation In Wireless Sensor Networks Based On Optimised Maximum Likelihood, Mohammed Rahman, Daryoush Habibi, Iftekhar Ahmad

Research outputs pre 2011

Maximum likelihood (ML) is a popular and effective estimator for a wide range of diverse applications and currently affords the most accurate estimation for source localisation in wireless sensor networks (WSN). ML however has two major shortcomings namely, that it is a biased estimator and is also highly sensitive to parameter perturbations. An Optimisation to ML (OML) algorithm was introduced that minimises the sum-of-squares bias and exhibits superior performance to ML in statistical estimation, particularly with finite datasets. This paper proposes a new model for acoustic source localisation in WSN, based upon the OML estimation process. In addition to the …


An Improved Fec Scheme For Mobile Wireless Communication At Vehicular Speeds, Iftekhar Ahmad, Daryoush Habibi, Ziaur Rahman Jan 2008

An Improved Fec Scheme For Mobile Wireless Communication At Vehicular Speeds, Iftekhar Ahmad, Daryoush Habibi, Ziaur Rahman

Research outputs pre 2011

WiMAX has emerged as a promising wireless communication technology with potential to deliver high throughput and guaranteed quality of service to the end applications. Recent studies suggest that while WiMAX (802.16e) is capable of delivering a data rate of up to 75 Mbps for fixed wireless communications, data rate decreases drastically for mobile wireless communications, often providing a data rate less than 1 Mb/s when the mobile nodes travel at vehicular speeds. High bit error rate caused at high vehicular speeds is the key reason for low throughput. In noisy mobile communication environments, standard error control mechanisms like the transmission …


Performance Evaluation Of Ieee 802.15.4 For Mobile Sensor Network, Kartinah Zen, Daryoush Habibi, Alexander Rassau, Iftekhar Ahmad Jan 2008

Performance Evaluation Of Ieee 802.15.4 For Mobile Sensor Network, Kartinah Zen, Daryoush Habibi, Alexander Rassau, Iftekhar Ahmad

Research outputs pre 2011

The IEEE 802.15.4 standard medium access control (MAC) protocol for low rate wireless personal area networks (LRWPAN) is design mainly for static sensor networks and its capability to support mobile sensor networks has not yet been established. To the best knowledge of authors, this is the first paper that evaluates the suitability of IEEE 802.15.4 MAC in mobile sensor networks environment. We evaluate the performance based on node's speed and beacon order, and observe the effect on energy usage, packet delivery ratio and time required to associate with its coordinator. From the experiment we observe that the moving nodes experienced …


Improving Mobile Sensor Connectivity Time In The Ieee 802.15.4 Networks, Kartinah Zen, Daryoush Habibi, Iftekhar Ahmad Jan 2008

Improving Mobile Sensor Connectivity Time In The Ieee 802.15.4 Networks, Kartinah Zen, Daryoush Habibi, Iftekhar Ahmad

Research outputs pre 2011

In the IEEE 802.15.4 medium access control (MAC) protocol for wireless sensor networks, a sensor node needs to associate with a coordinator before it starts sending or receiving data. The sensor node will mostly choose the nearest coordinator to associate with. However, this method is not suitable for a constantly moving sensor node because it will end up switching coordinators too often due to short connectivity time. The IEEE 802.15.4 has a simplistic and inadequate method of choosing a coordinator in this context. In this paper, we introduce a method to increase the mobile sensor node connectivity time with its …


Self-Restraint Admission Control For Ad-Hoc Wlans, Hushairi Zen, Daryoush Habibi, Iftekhar Ahmad Jan 2008

Self-Restraint Admission Control For Ad-Hoc Wlans, Hushairi Zen, Daryoush Habibi, Iftekhar Ahmad

Research outputs pre 2011

Admission control is an important mechanism for sustaining throughput and supporting quality of service (QoS) for real-time traffic in a wireless local area network (WLAN). In an adhoc WLAN scenario where no access point (AP) is available, admission control has to be self-managed by each node. We propose a self-restraining admission control mechanism that works by monitoring the congestion level of the network in the adhoc WLAN. Wireless nodes can listen to all nodes within their range and be aware of the collision rates. A node wishing to join the network measures the current collision rate, and predicts the post-admission …


Converging Voice, Video And Data In Wlan With Qos Support, Hushairi Zen, Daryoush Habibi, Justin Wyatt, Iftekhar Ahmad Jan 2008

Converging Voice, Video And Data In Wlan With Qos Support, Hushairi Zen, Daryoush Habibi, Justin Wyatt, Iftekhar Ahmad

Research outputs pre 2011

Providing quality of service (QoS) for converging traffic in wireless local area network (WLAN) is still a major issue for the researchers and industries. Due to the limited bandwidth and exposure to unpredictable interferences in a wireless environment, efficient management and optimization of the access protocols are essential to provide acceptable QoS for real-time traffic and fairness to best-effort traffic. In this paper, we investigate the throughput and delay performance of the legacy IEEE 802.11 and the 802.11e when carrying converging data in WLAN. We evaluate our recently proposed protocol known as wireless token network protocol (WTN) and show that …


Creating Preservation-Ready Web Resources, Joan A. Smith, Michael L. Nelson Jan 2008

Creating Preservation-Ready Web Resources, Joan A. Smith, Michael L. Nelson

Computer Science Faculty Publications

There are innumerable departmental, community, and personal web sites worthy of long-term preservation but proportionally fewer archivists available to properly prepare and process such sites. We propose a simple model for such everyday web sites which takes advantage of the web server itself to help prepare the site's resources for preservation. This is accomplished by having metadata utilities analyze the resource at the time of dissemination. The web server responds to the archiving repository crawler by sending both the resource and the just-in-time generated metadata as a straight-forward XML-formatted response. We call this complex object (resource + metadata) a CRATE. …


Efficient Corona Training Protocols For Sensor Networks, Alan A. Bertossi, Stephan Olariu, Cristina M. Pinotti Jan 2008

Efficient Corona Training Protocols For Sensor Networks, Alan A. Bertossi, Stephan Olariu, Cristina M. Pinotti

Computer Science Faculty Publications

Phenomenal advances in nano-technology and packaging have made it possible to develop miniaturized low-power devices that integrate sensing, special-purpose computing, and wireless communications capabilities. It is expected that these small devices, referred to as sensors, will be mass-produced and deployed, making their production cost negligible. Due to their small form factor and modest non-renewable energy budget, individual sensors are not expected to be GPS-enabled. Moreover, in most applications, exact geographic location is not necessary, and all that the individual sensors need is a coarse-grain location awareness. The task of acquiring such a coarse-grain location awareness is referred to as training. …