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2011

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Articles 1291 - 1320 of 1795

Full-Text Articles in Computer Sciences

Privacy Analysis Of User Association Logs In A Large-Scale Wireless Lan, Keren Tan, Guanhua Yan, Jihwang Yeo, David Kotz Jan 2011

Privacy Analysis Of User Association Logs In A Large-Scale Wireless Lan, Keren Tan, Guanhua Yan, Jihwang Yeo, David Kotz

Computer Science Technical Reports

User association logs collected from a large-scale wireless LAN record where and when a user has used the network. Such information plays an important role in wireless network research. One concern of sharing these data with other researchers, however, is that the logs pose potential privacy risks for the network users. Today, the common practice in sanitizing these data before releasing them to the public is to anonymize users' sensitive information, such as their devices' MAC addresses and their exact association locations. In this work, we demonstrate that such sanitization measures are insufficient to protect user privacy because the differences …


Software Development For A Three-Dimensional Gravity Inversion And Application To Study Of The Border Ranges Fault System, South-Central Alaska, Rolando Cardenas Jan 2011

Software Development For A Three-Dimensional Gravity Inversion And Application To Study Of The Border Ranges Fault System, South-Central Alaska, Rolando Cardenas

Open Access Theses & Dissertations

The Border Ranges Fault System (BRFS) bounds the Cook Inlet and Susitna Basins, an important petroleum province within south-central Alaska. A primary goal in the research is to test several plausible models of structure along the Border Ranges Fault System using a novel three-dimensional inversion utilizing gravity and magnetic data, constrained with other geophysical, borehole and surface geological information. This research involves the development of inversion modeling software using a Borland C++ compiler as part of the Rapid Application Development (RAD) Studio. The novel inversion approach directly models known geology, and "a priori" uncertainties on the geologic model to allow …


Prediction Of Ribonucleic Acid Secondary Structures Using A Heuristic Backtracking Search, Christopher Roman Cuellar Jan 2011

Prediction Of Ribonucleic Acid Secondary Structures Using A Heuristic Backtracking Search, Christopher Roman Cuellar

Open Access Theses & Dissertations

Ribonucleic acid (RNA) is essential for all forms of life. RNA is made up of a large chain of nucleotide bases: Guanine (G), Uracil (U), Cytosine (C), and Adenine (A). An RNA strand can fold on itself to allow G-C, A-U, and G-U bases to form hydrogen bonds, this is known as a secondary structure. Knowing the secondary structure of an RNA chain is very important because it will allow researchers to better understand its specific functions. RNA will create secondary structures that tend to minimize their free energy. RNA secondary structure prediction is the attempt to predict physical folding …


Estimating Statistical Characteristics Under Interval Uncertainty And Constraints: Mean, Variance, Covariance, And Correlation, Ali Jalal-Kamali Jan 2011

Estimating Statistical Characteristics Under Interval Uncertainty And Constraints: Mean, Variance, Covariance, And Correlation, Ali Jalal-Kamali

Open Access Theses & Dissertations

In many practical situations, we have a sample of objects of a given type. When we measure the values of a certain quantity x for these objects, we get a sequence of values x1, . . . , xn. When the sample is large enough, then the arithmetic mean E of the values xi is a good approximation for the average value of this quantity for all the objects from this class. Other expressions provide a good approximation to statistical characteristics such as variance, covariance, and correlation.

The values xi come from measurements, and measurement is never absolutely accurate.

Often, …


Deciphering The Story Of The Musuem, Eoin Kilfeather Jan 2011

Deciphering The Story Of The Musuem, Eoin Kilfeather

Publications

No abstract provided.


An Event-Based Approach To Describing And Understanding Museum Narratives, Paul Mulholland, Annika Wolff, Trevor Collins, Zdenek Zdrahal Jan 2011

An Event-Based Approach To Describing And Understanding Museum Narratives, Paul Mulholland, Annika Wolff, Trevor Collins, Zdenek Zdrahal

Publications

Current museum metadata tends to be focused around the properties of the heritage object such as the artist, style and date of creation. This form of metadata can index a museum’s collection but cannot express the relations between heritage objects and related concepts found in contemporary museum exhibitions. A modern museum exhibition, rather than providing a taxonomic classification of heritage objects, uses them in the construction of curatorial narratives to be interpreted by an audience. In this paper we outline how curatorial narratives can be represented semantically using our Curate Ontology. The Curate Ontology, informed by a detailed analysis of …


Obtaining The Secondary Impedance Of Single-Sided Linear Induction Motor With A Double Layer Reaction Rail: A New Approach, Ali̇ Suat Gerçek, Vedat Mehmet Karsli Jan 2011

Obtaining The Secondary Impedance Of Single-Sided Linear Induction Motor With A Double Layer Reaction Rail: A New Approach, Ali̇ Suat Gerçek, Vedat Mehmet Karsli

Turkish Journal of Electrical Engineering and Computer Sciences

In the performance calculations of single-sided linear induction motor (SLIM),the equivalent circuit technique (ECT) is used. In this paper, a new approach is proposed for obtaining the secondary impedance of single-sided linear induction motor (SLIM) with a double layer reaction rail by using the layered secondary model. The proposed method improves the ECT technique by considering the saturation effect and the non-linear complex equivalent relative permeability. This study also examines the contributions of other electromagnetic effects, such as longitudinal end effect and transverse edge effect as well. Our method is applied to the SLIM and computed results of the method …


A Logic Method For Efficient Reduction Of The Space Complexity Of The Attribute Reduction Problem, Mehmet Hacibeyoğlu, Fati̇h Başçi̇ftçi̇, Şi̇rzat Kahramanli Jan 2011

A Logic Method For Efficient Reduction Of The Space Complexity Of The Attribute Reduction Problem, Mehmet Hacibeyoğlu, Fati̇h Başçi̇ftçi̇, Şi̇rzat Kahramanli

Turkish Journal of Electrical Engineering and Computer Sciences

The goal of attribute reduction is to find a minimal subset (MS) R of the condition attribute set C of a dataset such that R has the same classification power as C. It was proved that the number of MSs for a dataset with n attributes may be as large as (_{n/2}^n) and the generation of all of them is an NP-hard problem. The main reason for this is the intractable space complexity of the conversion of the discernibility function (DF) of a dataset to the disjunctive normal form (DNF). Our analysis of many DF-to-DNF conversion processes showed that approximately …


Performance Evaluation Of Nonparametric Ica Algorithm For Fetal Ecg Extraction, Yusuf Sevi̇m, Ayten Atasoy Jan 2011

Performance Evaluation Of Nonparametric Ica Algorithm For Fetal Ecg Extraction, Yusuf Sevi̇m, Ayten Atasoy

Turkish Journal of Electrical Engineering and Computer Sciences

Fetal electrocardiograms (FECG) contain important indications about the health and condition of the fetus. In this respect, it is crucial to apply a robust algorithm to ECG data for extraction of the FECG signal. Most of the independent component analysis (ICA) algorithms used for this purpose rely on simple statistical models. Such algorithms can fail to separate desired signals when the assumed statistical model is inaccurate. Statistical models can be estimated accurately using kernel density estimation methods. Therefore, the kernel density estimation method was used in this paper for building an ICA algorithm (nonparametric ICA: NpICA) and the algorithm was …


A Vision Based Feedback Mechanism For 6-Dof Stewart Platform, Utku Büyükşahi̇n Jan 2011

A Vision Based Feedback Mechanism For 6-Dof Stewart Platform, Utku Büyükşahi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

Eyes are the most ubiquitous sensors of humankind. However, ``Vision Based Sensors" are not as common as what this fact would suggest. A survey of the previous work on image processing would reveal that the bulk of the research in this area have been conducted since the year 2000. These facts clearly show that image processing is the technology of our century, and is very open to further development. In this work, a system that combines a classical mechanism of the 20th century with the recent technology of the 21st century is presented and the design, theoretical background, the software …


Designing A Knowledge Distribution Simulator, Martin Hill, Graham Fletcher Jan 2011

Designing A Knowledge Distribution Simulator, Martin Hill, Graham Fletcher

Australian Information Warfare and Security Conference

To make good decisions, we need to be suitably informed. 'Good' and 'Suitably' in this case depend on the informational needs of the decision and the mechanisms of getting the information to the decision maker in time. The trade-offs in qualities, quantities, timeliness, impacts on other activities, and so on are infamously wickedly complex, and usually buried in a clutter of special circumstances, personality characteristics, environments unsuitable for study, and so on. Decision-making systems can be explored using case studies and exercises, but these are limited by the expense and time of using real people. A virtual simulator for large …


Interoperability Gap Challenges For Learning Object Repositories & Learning Management Systems, Robert T. Mason Jan 2011

Interoperability Gap Challenges For Learning Object Repositories & Learning Management Systems, Robert T. Mason

CCAC Theses and Dissertations

An interoperability gap exists between Learning Management Systems (LMSs) and Learning Object Repositories (LORs). Learning Objects (LOs) and the associated Learning Object Metadata (LOM) that is stored within LORs adhere to a variety of LOM standards. A common LOM standard found in LORs is the Sharable Content Object Reference Model (SCORM) Content Aggregation Model (CAM). In contrast, LMSs are independent computer systems that manage and deliver course content to students via a web interface. This research addressed three important issues related to the interoperability gap: (a) a lack of a metadata standard that defined the format of how student assessment …


Computer Music Composition Using Crowdsourcing And Genetic Algorithms, Jessica Faith Keup Jan 2011

Computer Music Composition Using Crowdsourcing And Genetic Algorithms, Jessica Faith Keup

CCAC Theses and Dissertations

When genetic algorithms (GA) are used to produce music, the results are limited by a fitness bottleneck problem. To create effective music, the GA needs to be thoroughly trained by humans, but this takes extensive time and effort. Applying online collective intelligence or "crowdsourcing" to train a musical GA is one approach to solve the fitness bottleneck problem. The hypothesis was that when music was created by a GA trained by a crowdsourced group and music was created by a GA trained by a small group, the crowdsourced music would be more effective and musically sound. When a group of …


The Blended Learning Experience Of Community College Students, Anita Bleffert-Schmidt Jan 2011

The Blended Learning Experience Of Community College Students, Anita Bleffert-Schmidt

CCAC Theses and Dissertations

Blended learning has sometimes been calledthe best of both worlds, combining the advantages of face-to-face instruction with the advantages of online learning. It has been in existence for over a decade, and more research needed to be done to determine its efficacy and desirability for community colleges. The goal of this dissertation was to document the ways in which blended learning has changed the community college learning experience.

The investigation took place at Ulster County Community College, a small rural college in upstate New York. A mixed method, triangulation design was used. Quantitative data were collected from the college's student …


The Impact Of The User Interface On Simulation Usability And Solution Quality, Bruce Ray Montgomery Jan 2011

The Impact Of The User Interface On Simulation Usability And Solution Quality, Bruce Ray Montgomery

CCAC Theses and Dissertations

This research outlines a study that was performed to determine the effects of user interface design variations on the usability and solution quality of complex, multivariate discrete-event simulations. Specifically, this study examined four key research questions: what are the user interface considerations for a given simulation model, what are the current best practices in user interface design for simulations, how is usability best evaluated for simulation interfaces, and specifically what are the measured effects of varying levels of usability of interface elements on simulation operations such as data entry and solution analysis. The overall goal of the study was to …


A Domain Aware Genetic Algorithm For The P-Median Problem, Dennis Vickers Jan 2011

A Domain Aware Genetic Algorithm For The P-Median Problem, Dennis Vickers

CCAC Theses and Dissertations

The p-median problem is an NP-complete combinatorial optimization problem often used in the fields of facility location and clustering. Given a graph with n nodes and an integer p < n, the p-median problem seeks a set of p medians such that the sum of the distances of the n nodes from their nearest median is minimized. This dissertation develops a genetic algorithm that generates solutions to the p-median problem that improves on previously published genetic algorithms by implementing operators that exploit domain specific information. More specifically, this GA explores the following:

(1) The advantages of using "good" solutions generated using extant heuristics in the initial generation of chromosomes.

(2) The effectiveness of a crossover operation that exchanges centers in the same neighborhood rather than exchanging arbitrarily chosen subsets of centers.

(3) The efficacy of using a biased mutation operator that favors replacing existing medians from less fit chromosomes with non-median nodes from the same neighborhood as the median being replaced.

Using published …


Experimental Analysis Of An Alternator Excited With Photovoltaic Cells For Small Power Plants, Kami̇l Ri̇fat İrfan Güney, Nevzat Onat Jan 2011

Experimental Analysis Of An Alternator Excited With Photovoltaic Cells For Small Power Plants, Kami̇l Ri̇fat İrfan Güney, Nevzat Onat

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, an automatic voltage regulator fed by photovoltaic (PV) cells was designed for use in small power alternators. The design aimed to increase the energy output of the alternator and to ensure necessary current output from the PV cells to support the synchronous generator excitation system. For energy transformation from small renewable energy sources, designers have favored the use of alternators that produce higher quality electric power, rather than asynchronous generators. We also address the designed system's suitability for real-life application, examining the steady-state performance of the photovoltaic cell excited alternator (PVCEA) with various loads and its behavior …


The Application Of Data Mining Techniques To Interrogate Western Australian Water Catchment Data Sets, Ajdin Sehovic Jan 2011

The Application Of Data Mining Techniques To Interrogate Western Australian Water Catchment Data Sets, Ajdin Sehovic

Theses : Honours

Current environmental challenges such as increasing dry land salinity, waterlogging, eutrophication and high nutrient runoff in south western regions of Western Australia may have both cultural and environmental implications in the near future. Advances in computer science disciplines, more specifically, data mining techniques and geographic information services provide the means to be able to conduct longitudinal climate studies to predict changes in the Water catchment areas of Western Australia.

The research proposes to utilise existing spatial data mining techniques in conjunction of modern open-source geospatial tools to interpret trends in Western Australian water catchment land use. This will be achieved …


Let's Not Kill All The Privacy Laws (And Lawyers), Fred H. Cate, Christopher Kuner, Christopher Millard, Dan Jerker B. Svantesson Jan 2011

Let's Not Kill All The Privacy Laws (And Lawyers), Fred H. Cate, Christopher Kuner, Christopher Millard, Dan Jerker B. Svantesson

Articles by Maurer Faculty

No abstract provided.


Privacy -- An Elusive Concept, Fred H. Cate, Christopher Kuner, Christopher Millard, Dan Jerker B. Svantesson Jan 2011

Privacy -- An Elusive Concept, Fred H. Cate, Christopher Kuner, Christopher Millard, Dan Jerker B. Svantesson

Articles by Maurer Faculty

No abstract provided.


Editorial, Fred H. Cate, Christopher Kuner, Christopher Millard, Dan Jerker B. Svantesson Jan 2011

Editorial, Fred H. Cate, Christopher Kuner, Christopher Millard, Dan Jerker B. Svantesson

Articles by Maurer Faculty

No abstract provided.


Wiki Behavior In The Workplace: Emotional Aspects Of Content Development, Deborah A. Gears Jan 2011

Wiki Behavior In The Workplace: Emotional Aspects Of Content Development, Deborah A. Gears

CCAC Theses and Dissertations

Wikis have been found to be an easy-to-use, low-cost, and Internet-based technology useful in creating and mobilizing knowledge. Wikis hosted within firms (corporate wikis) have become a popular way for employees to share information and collaborate.

Preliminary research suggested that as few as 6% of wiki consumers contributed to the development of wiki pages. Conventional approaches argued that employees judged the costs of participating in wikis (e.g., authoring or changing material, reading messages, following an argument, and posting responses) to exceed the benefits of participating in wikis (e.g., recognition, reputation etc.) - thus many people "lurked" but did not post. …


Autonomous Entropy-Based Intelligent Experimental Design, Nabin Kumar Malakar Jan 2011

Autonomous Entropy-Based Intelligent Experimental Design, Nabin Kumar Malakar

Legacy Theses & Dissertations (2009 - 2024)

The aim of this thesis is to explore the application of probability and information theory in experimental design, and to do so in a way that combines what we know about inference and inquiry in a comprehensive and consistent manner.


Distributed Replica Placement With Network Coordinates, Fan Ping Jan 2011

Distributed Replica Placement With Network Coordinates, Fan Ping

Legacy Theses & Dissertations (2009 - 2024)

Recent years have witnessed a proliferation of large scale distributed systems that manage massive amounts of data at diverse geographic locations. In such systems, the overall system performance can be significantly affected by the round-trip time between computing nodes. Thus, efficiently and accurately measuring or estimating network latency is a key requirement.


The Forest Overlay Network, Logan Stafman Jan 2011

The Forest Overlay Network, Logan Stafman

All Computer Science and Engineering Research

Forest is an overlay network designed for large real-time distributed systems. In particular, we’re interested in virtual worlds that provide high-quality interaction over a constantly changing pattern of communication. Forest is suitable for applications in which many entities send data to a large set of constantly changing entities. By using tree-structured channels, we can create logically isolated private networks which support both unicast and multicast routing. In this paper, we will discuss the core components of Forest and measure the performance of the control elements of the network. We will also provide examples of control sequences and the roles played …


Mercury Blastn Biosequence Similarity Search System: Technical Reference Guide, Jeremy Buhler Jan 2011

Mercury Blastn Biosequence Similarity Search System: Technical Reference Guide, Jeremy Buhler

All Computer Science and Engineering Research

This guide documents the operation of the Mercury BLASTN system for hardware-accelerated DNA similarity search. It includes detailed information on the syntax and limitations of the system's component commands, as well as a description of the system's hardware platform suitable for administrators who need to maintain a Mercury BLASTN system. Mercury BLASTN is a product of the High Performance COmputational Biology Group at Washington University.


Efficient Deadlock Avoidance For Streaming Computation With Filtering, Jeremy Buhler, Kunal Agrawal, Peng Li, Roger D. Chamberlain Jan 2011

Efficient Deadlock Avoidance For Streaming Computation With Filtering, Jeremy Buhler, Kunal Agrawal, Peng Li, Roger D. Chamberlain

All Computer Science and Engineering Research

In this report, we show that deadlock avoidance for streaming computations with filtering can be performed efficiently for a large class of DAG topologies. We first give efficient algorithms for dummy interval computation in series-parallel DAGs, then generalize our results to a larger graph family, the CS4DAGs, in which every undirected cycle has exactly one source and one sink. Our results show that, for a large set of application topologies that are both intuitively useful and formalizable, the streaming model with filtering can be implemented safely with reasonable compilation overhead.


Hierarchical Scheduling For Multicores With Multilevel Cache Hierarchies, Kunal Agrawal, Jim Sukha Jan 2011

Hierarchical Scheduling For Multicores With Multilevel Cache Hierarchies, Kunal Agrawal, Jim Sukha

All Computer Science and Engineering Research

Cache-locality is an important consideration for the performance in multicore systems. In modern and future multicore systems with multilevel cache hierarchies, caches may be arranged in a tree of caches, where a level k cache is shared between Pk processors, called a processor group, and Pk increases with k. In order to get good performance, as much as possible, subcomputations that share more data should execute on processors which share a lower-level cache. Therefore, the number of cache misses in these systems depends on the scheduling decisions, and a scheduler is responsible for not just achieving good load-balance and low …


Near Optimal Rate Selection For Wireless Control Systems, Abusayeed Saifullah, Chengjie Wu, Paras Babu Tiwari, You Xu, Yong Fu, Chenyang Lu, Yixin Chen Jan 2011

Near Optimal Rate Selection For Wireless Control Systems, Abusayeed Saifullah, Chengjie Wu, Paras Babu Tiwari, You Xu, Yong Fu, Chenyang Lu, Yixin Chen

All Computer Science and Engineering Research

With the advent of industrial standards such as WirelessHART, process industries are now gravitating towards wireless control systems. Due to limited bandwidth in a wireless network shared by multiple control loops, it is critical to optimize the overall control performance. In this paper, we address the scheduling-control co-design problem of determining the optimal sampling rates of feedback control loops sharing a WirelessHART network. The objective is to minimize the overall control cost while ensuring that all data flows meet their end-to-end deadlines. The resulting constrained optimization based on existing delay bounds for WirelessHART networks is challenging since it is non-differentiable, …


Distributed Channel Allocation Algorithms For Wireless Sensor Networks, Abusayeed Saifullah, You Xu, Chenyang Lu, Yixin Chen Jan 2011

Distributed Channel Allocation Algorithms For Wireless Sensor Networks, Abusayeed Saifullah, You Xu, Chenyang Lu, Yixin Chen

All Computer Science and Engineering Research

Interference between concurrent transmissions can cause severe performance degradation in wireless sensor networks (WSNs). While multiple channels available in WSN technology such as IEEE 802.15.4 can be exploited to mitigate interference, channel allocation can have a significant impact on the performance of multi-channel communication. This paper proposes a set of distributed algorithms for near-optimal channel allocation in WSNs with theoretical bounds. We first consider the problem of minimizing the number of channels needed to remove interference in a WSN, and propose both receiver-based and link-based distributed channel allocation protocols. For WSNs with an insufficient number of channels, we formulate a …