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2006

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Articles 331 - 360 of 5872

Full-Text Articles in Physical Sciences and Mathematics

Runtime Optimization And Load Shedding In Mavstream: Design And Implementation, Balakumar Kendai Dec 2006

Runtime Optimization And Load Shedding In Mavstream: Design And Implementation, Balakumar Kendai

Computer Science and Engineering Theses

In data stream processing systems Quality of Service (or QoS) is extremely important. The system should try its best to meet the QoS requirements specified by a user. On account of this difference, unlike in a database management system, a query cannot be optimized once and executed. It has been shown that different scheduling strategies are useful in trading tuple latency requirements with memory and throughput requirements. In addition, data stream processing systems may experience significant fluctuations in input rates. In order to meet the QoS requirements of data stream processing, a runtime optimizer equipped with several scheduling and load …

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Compensation Of Photobleached Images For A Cell Dynamics System, Sowmya Gopinath Dec 2006

Compensation Of Photobleached Images For A Cell Dynamics System, Sowmya Gopinath

Computer Science and Engineering Theses

Progress in the field of medicine attributes to the discoveries in biology that require an extensive knowledge of cell dynamics. Intracellular Cell Dynamics Analysis System (ICellDAS) is a web based tool aimed at automating sub cellular particle motion estimation, tracking and mobility analysis. The purpose of this tool is to develop a better understanding of specific biology problems by visualizing biological data. For reliable analysis as well as visualization of cell dynamics, it is essential that the acquired images reflect the exact information of the specimen. The goal of the thesis is to design an interface for the ICellDAS project …

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Analyzing Differences In Color Variation Sensitivity Between Experts And Novices To Find A Differentiating Process In Pigmented Skin Lesion Diagnosis, Yu-Chin Chai Dec 2006

Analyzing Differences In Color Variation Sensitivity Between Experts And Novices To Find A Differentiating Process In Pigmented Skin Lesion Diagnosis, Yu-Chin Chai

Computer Science and Engineering Theses

Fatal skin lesions such as melanomas appear as having high color variation to experts but often as having low variation to novices. This thesis investigated if it is possible to find a function representing an expert's color variation sensitivity to skin lesions without explicitly requiring them to provide a diagnosis. Various pigmented skin images with either normal pigmentation or with diseased lesions were evaluated by experts and novices. To determine the best color space for lesion differentiation, an optimization process based on parametric color dimensions in a RGB color space was used to find the parameters of a color transformation …

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Using Part Of Speech Structure Of Text In The Prediction Of Its Readability, Jagadeesh Kondru Dec 2006

Using Part Of Speech Structure Of Text In The Prediction Of Its Readability, Jagadeesh Kondru

Computer Science and Engineering Theses

Readability formulas predict the reading difficulty associated with text. They typically output a U.S. school grade level that indicates the reading ability required of a person in order for him to comprehend that text. Ability to predict text readability is useful because it helps educators select appropriate texts for students and authors write texts accessible to the audience they target. Existing readability formulas are based on countable aspects of the text such as average sentence length and average word length. We propose a new readability formula, the Readability Index, which is based on the part-of-speech structure of sentences in a …

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Ca-Ole- A Collaborative And Adaptive Online Learning Environment, Paola Gomez Dec 2006

Ca-Ole- A Collaborative And Adaptive Online Learning Environment, Paola Gomez

Computer Science and Engineering Theses

Demand for online learning environments has grown in the past few years, and schools have been offering more distance courses to their students. Designing adequate online learning environments is considerably more challenging than conventional Face-To-Face courses; therefore traditional methods can not be used. This thesis proposes the creation of a Collaborative and Adaptive Online Learning Environment (CA-OLE) that provides a structure where instructors can combine their lesson materials with an adaptive system and collaborative tools. CA-OLE innovative approach consists of an adaptive framework that changes the way the learning materials prepared by instructors are presented to the students depending on …

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Personalizing (Re-Ranking) Web Search Results Using Information Present On A Social Network, Sushruth Puttaswamy Dec 2006

Personalizing (Re-Ranking) Web Search Results Using Information Present On A Social Network, Sushruth Puttaswamy

Computer Science and Engineering Theses

We describe a social search engine paradigm which can be built on top of a classic search engine (e.g. Google, Yahoo, etc.) and a social information network (such as FriendSter). In this thesis, the objective was to design algorithms and develop methods to efficiently combine information available in the underlying systems (Search Engine & Social Information Network) to better satisfy the search needs of a user. We are interested on how to efficiently employ social information to re-order a list of URLs retrieved by querying a search engine. The objective was to re-order the list of URLs in a way …

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Adaptive Load Balancing And Change Visualization For Webvigil, Subramanian Chelladurai Hari Hara Dec 2006

Adaptive Load Balancing And Change Visualization For Webvigil, Subramanian Chelladurai Hari Hara

Computer Science and Engineering Theses

There is a need for selective monitoring, the contents of web pages. Periodical visit for understanding changes to a web page is both inefficient and time consuming. WebVigiL is a system developed for automating the change detection and timely notification of HTML/XML pages based on user specified changes of interest. User interest, specified as a sentinel/profile, is automatically monitored by the system using a combination of learning-based and event-driven techniques. The first prototype concentrated on the functionality of the WebVigiL system. This thesis extends the WebVigiL system in a number of ways. The primary focus of this thesis is the …

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Efficient Main Memory Algorithms For Significant Interval And Frequent Episode Discovery, Sagar Hasmukh Savla Dec 2006

Efficient Main Memory Algorithms For Significant Interval And Frequent Episode Discovery, Sagar Hasmukh Savla

Computer Science and Engineering Theses

There is a considerable research on sequential mining of time-series data. Sensor-based applications such as MavHome require prediction of events for automating the environment using time-series data collected over a period of time. In these applications, it is important to predict tight and accurate intervals of interest to effectively automate the application. Also, detection of frequent patterns is needed for the automation of sequence of happenings. Although, there is a considerable body of work on sequential mining of transactional data, most of them deal with time point data and make several iterations over the entire data set for discovering frequently …

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Automated Software Testing Using Covering Arrays, Chinmay P. Jayaswal Dec 2006

Automated Software Testing Using Covering Arrays, Chinmay P. Jayaswal

Computer Science and Engineering Theses

Modern society is increasingly dependent on the quality of software systems. Software testing is a widely used approach to ensure software quality. Since exhaustive testing is impractical due to resource constraints, it is necessary to strike a balance between test efforts and quality assurance. Interaction testing is one approach to marrying these two qualities. It characterizes the system under test by a set of parameters and the respective test values (domain size) for each parameter. Instead of testing all possible combinations of values for all the parameters, interaction testing constructs a covering array as a test set to cover all …

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End-To-End Optimal Algorithms For Traffic Engineering, Failure Detection And Recovery In Connectionless Networks, Sukruth Srikantha Dec 2006

End-To-End Optimal Algorithms For Traffic Engineering, Failure Detection And Recovery In Connectionless Networks, Sukruth Srikantha

Computer Science and Engineering Theses

In this thesis we propose a novel scheme to achieve intra-domain Traffic Engineering (TE), Failure Detection and Recovery (FR) in connectionless networks. This scheme addresses rate adaptation, load balancing and stability issues of the OSPF protocol namely, network convergence times and route flapping. With the current default settings of the OSPF parameters, the network takes several tens of seconds to recover from a failure. The main component in this delay is the time required to detect the failure using the Hello protocol. Route flap is another undesirable phenomenon and needs to be eliminated to achieve greater stability and robustness in …

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Evading Existing Stepping Stone Detection Methods Using Buffering, Madhu Venkateshaiah Dec 2006

Evading Existing Stepping Stone Detection Methods Using Buffering, Madhu Venkateshaiah

Computer Science and Engineering Theses

To gain anonymity and complicate their apprehension, attackers launch attacks not from their own systems but from previously compromised systems called stepping stones. An effective way to detect stepping stones is by comparing of incoming and outgoing connections in a network to find correlations. For the sake of simplicity, earlier approaches ignore that an attacker can add chaff to a traffic stream. But in reality, the attacker may be able to modify applications to use cover traffic. We loosen some assumptions made by earlier researchers and propose a simple buffering technique that could be used by an attacker to evade …

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A Distributed Sensor Data Management Infrastructure Based On 802.15.4/Zigbee Networks, Tianqiang Li Dec 2006

A Distributed Sensor Data Management Infrastructure Based On 802.15.4/Zigbee Networks, Tianqiang Li

Computer Science and Engineering Theses

Wireless sensor networks consist of a certain number of autonomous devices with sensor, every device has certain detection functionality like light, temperature pressure etc. Communication by using the radio frequency make these spatially distributed devices feasible to oversee the activities in a large scale of area/space. 802.15.4/ZigBee networks are slated to run in the unlicensed frequencies. It is a packet-based radio protocol aimed at very low-cost, battery-operated widgets and sensors that can intercommunicate and send low-bandwidth data to each other. This thesis covers the content of a software solution of data management for an 802.15.4 networks. Its main contribution lies …

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Tracing And Replay Of Real-Time Concurrent Programs In Vxworks, Daxa Keshavji Patel Dec 2006

Tracing And Replay Of Real-Time Concurrent Programs In Vxworks, Daxa Keshavji Patel

Computer Science and Engineering Theses

Real-time concurrent programs are difficult to analyze, debug and test because of the existence of race conditions. In particular, cyclic debugging requires the ability to reproduce a failed execution. That is, when a failure is observed during a test run, it is often necessary to reproduce the test run as an effort to locate the bug that has caused the failure. However because of the variations in thread scheduling and signal latency, a real-time concurrent execution may not be reproduced simply by re-executing the program under test. In this thesis, we describe a language-based framework for tracing and replay of …

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Performance Analysis Of The Beacon Period Contraction Mechanism In Wimedia Mac For Uwb, Shenjin Sun Dec 2006

Performance Analysis Of The Beacon Period Contraction Mechanism In Wimedia Mac For Uwb, Shenjin Sun

Computer Science and Engineering Theses

The WiMedia MAC for UWB based WPANs is currently preferred among standards for wireless network since it requires non-infrastructure for ad hoc network, and also supports for Quality of Service (QoS). Without infrastructure, coordination of devices within radio range is achieved by the exchange of beacon frames, which is an overhead in WiMedia MAC, since no data transmission is allowed during Beacon Period (BP). In a dynamic network, devices might leave or join in, so beacon slots will be released or reoccupied with the changing of network. And BP contraction mechanism is aimed at reusing the released beacon slots in …

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Holographic Patterning Of Polymer Dispersed Liquid Crystal Materials For Diffractive Optical Elements, Robert Allan Ramsey Dec 2006

Holographic Patterning Of Polymer Dispersed Liquid Crystal Materials For Diffractive Optical Elements, Robert Allan Ramsey

Physics Dissertations

Liquid crystals are a soft condensed matter phase that share properties with both isotropic liquids and crystalline solids. Composite materials formed from both low molecular weight liquid crystals and polymers are of both fundamental and technological importance. One method for preparing dispersions of polymers and liquid crystals is polymerization-induced phase separation. Photo-polymerization induced phase separation utilizes a mixture of a liquid crystal and a photo curable polymer contained between two indium tin-oxide (ITO) coated glass substrates. Irradiation of the homogeneous pre-polymer mixture initiates polymerization, which in turn induces a phase separation between the polymer and liquid crystal. Holographically patterned polymer …

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Finding A Length-Constrained Maximum-Sum Or Maximum-Density Subtree And Its Application To Logistics, Hoong Chuin Lau, Trung Hieu Ngo, Bao Nguyen Nguyen Dec 2006

Finding A Length-Constrained Maximum-Sum Or Maximum-Density Subtree And Its Application To Logistics, Hoong Chuin Lau, Trung Hieu Ngo, Bao Nguyen Nguyen

Research Collection School Of Computing and Information Systems

We study the problem of finding a length-constrained maximum-density path in a tree with weight and length on each edge. This problem was proposed in [R.R. Lin, W.H. Kuo, K.M. Chao, Finding a length-constrained maximum-density path in a tree, Journal of Combinatorial Optimization 9 (2005) 147–156] and solved in O(nU) time when the edge lengths are positive integers, where n is the number of nodes in the tree and U is the length upper bound of the path. We present an algorithm that runs in O(nlog2n) time for the generalized case when the edge lengths are positive real numbers, which …

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Surface Modification Of Pigments And Its Role In Offset Ink Setting, Wei Gu Dec 2006

Surface Modification Of Pigments And Its Role In Offset Ink Setting, Wei Gu

Electronic Theses and Dissertations

Ink setting affects offset print quality issues such as print mottle and print gloss. It is known that ink setting depends on many factors, such as the nature of the substrate, the properties of the coating, and the ink formulation. However, the role of pigment surface chemistry in offset ink setting is unknown. From an experimental perspective, it is difficult to determine the role of the surface chemistry as it requires paper coatings that are similar in physical properties and differ only in the pigment surface chemistry. The aim of this study was two-fold. The first was to apply methods …

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Expression And Characterization Of Hyperthermophilic Aqujfex Pyrophilus Flagellin Protein In Mesophilic Bacterial Systems, Srivani V. Mukkamala Dec 2006

Expression And Characterization Of Hyperthermophilic Aqujfex Pyrophilus Flagellin Protein In Mesophilic Bacterial Systems, Srivani V. Mukkamala

Masters Theses

The structural protein flagellin, FlaA derived from hyperthermophilic Aquifex pyrophilus, a rod shaped eubacterial species that grows near hydrothermal vents at an optimum growth temperature of 85 °C forms elongated thermostable flagella nanotubes. FlaA was successfully over-expressed for the first time using pET28c plasmid in E. coli BL21 cells at 37 °C. The protein was isolated from inclusion bodies that were solubilized by alkaline pH, refolded by dialysis and purified by chromatographic techniques. The FlaA was characterized by fluorescence, light scattering and circular dichroism. The FlaA was not in the correct folded form to form flagella as efforts to …

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Modeling Soil Erosion In The Upper Green River, Ky, Narcisa Pricope Dec 2006

Modeling Soil Erosion In The Upper Green River, Ky, Narcisa Pricope

Masters Theses & Specialist Projects

Off-site soil erosion has tremendous impacts on the present state of most river systems throughout the United States, contributing sediments to channels mainly as nonpoint pollution resulting from land-use and agricultural practices and leading to sedimentation downstream and downwind, a decrease in the transport capacity of streams, increase in the risk of flooding, filling reservoirs, and eutrophication. A primary focus in examining the problems associated with soil erosion arid ultimately in proposing control measures should be on identifying the sources of the sediment. Therefore, a model that would be able to assess soil erosion needs to start by identifying the …

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Assessment Of Atrazine In A Rural Water Source: Rough River Lake, Kentucky, Scotty Sharp Dec 2006

Assessment Of Atrazine In A Rural Water Source: Rough River Lake, Kentucky, Scotty Sharp

Masters Theses & Specialist Projects

Atrazine [2-chloro- 4-(ethylamino)-6-(isopropylamino)-l,3,5-triazine], a widely used herbicide in US corn production, impacts quality of drinking water for many rural water supply systems. Four systems at Rough River Lake, Kentucky, have had high levels of atrazine in raw water and in some cases finished water that have exceeded the legal limit of 3 parts per billion (ppb). The Rough River Lake watershed is 1,700-km2, much of which is located in limestone karst. A hypothesis was developed stating that there would be higher concentrations of atrazine in the northeast section of the Rough River Watershed, located in Hardin County, due to the …

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Flash Flooding In Eastern Kentucky: An Analysis Of The 3-4 August 2001 Event, Christina Henry Dec 2006

Flash Flooding In Eastern Kentucky: An Analysis Of The 3-4 August 2001 Event, Christina Henry

Masters Theses & Specialist Projects

Limited research exists concerning flash flooding in the United States. However, flash floods can occur anywhere and cause more fatalities than any other weather related natural disaster. Eastern Kentucky experienced an average of 41 flash floods per year (1993-2002), yet little research exists for this region. Therefore, this paper presents an analysis of the particularly devastating flash flood event of 3-4 August 2001, which resulted in $15 million worth of property damage and two deaths. Previous studies indicate that flash floods typically occur under relatively 'benign' conditions, the most common characteristics being a quasi-stationary system and high atmospheric moisture. The …

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Clique Percolation For Finding Naturally Cohesive And Overlapping Document Clusters, Wei Gao, Kam-Fai Wong, Yunqing Xia, Ruifeng Xu Dec 2006

Clique Percolation For Finding Naturally Cohesive And Overlapping Document Clusters, Wei Gao, Kam-Fai Wong, Yunqing Xia, Ruifeng Xu

Research Collection School Of Computing and Information Systems

Techniques for find document clusters mostly depend on models that impose strong explicit and/or implicit priori assumptions. As a consequence, the clustering effects tend to be unnatural and stray away from the intrinsic grouping natures of a document collection. We apply a novel graph-theoretic technique called Clique Percolation Method (CPM) for document clustering. In this method, a process of enumerating highly cohesive maximal document cliques is performed in a random graph, where those strongly adjacent cliques are mingled to form naturally overlapping clusters. Our clustering results can unveil the inherent structural connections of the underlying data. Experiments show that CPM …

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A Statistical Analysis Of Wide Binary Evolution, Kyle Burton Johnston Dec 2006

A Statistical Analysis Of Wide Binary Evolution, Kyle Burton Johnston

Theses and Dissertations

Post main sequence (MS) mass loss causes orbital separation amplification in fragile (i.e. common proper motion) binary star systems. Components typically have separations around -1000 a.u. Such wide pairs experience negligible tidal interactions and mass transfer between companions; they evolve as two separate but coeval stars. In this paper we will attempt to model how post-MS mass loss statistically distorts a frequency distribution of fragile binary separations. Understanding this process provides a robust test of current theories of stellar evolution and sets constraints on the dynamics of the Galactic disk.

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Cosign: A Parallel Algorithm For Coordinated Traffic Signal Control, Shih-Fen Cheng, Marina A. Epelman, Robert L. Smith Dec 2006

Cosign: A Parallel Algorithm For Coordinated Traffic Signal Control, Shih-Fen Cheng, Marina A. Epelman, Robert L. Smith

Research Collection School Of Computing and Information Systems

The problem of finding optimal coordinated signal timing plans for a large number of traffic signals is a challenging problem because of the exponential growth in the number of joint timing plans that need to be explored as the network size grows. In this paper, the game-theoretic paradigm of fictitious play to iteratively search for a coordinated signal timing plan is employed, which improves a system-wide performance criterion for a traffic network. The algorithm is robustly scalable to realistic-size networks modeled with high-fidelity simulations. Results of a case study for the city of Troy, MI, where there are 75 signalized …

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Dynamic Multi-Linked Negotiations In Multi-Echelon Production Scheduling Networks, Hoong Chuin Lau, Guan Li Soh, Wee Chong Wan Dec 2006

Dynamic Multi-Linked Negotiations In Multi-Echelon Production Scheduling Networks, Hoong Chuin Lau, Guan Li Soh, Wee Chong Wan

Research Collection School Of Computing and Information Systems

In this paper, we are concerned with scheduling resources in a multi-tier production/logistics system for multi-indenture goods. Unlike classical production scheduling problems, the problem we study is concerned with local utilities which are private. We present an agent model and investigate an efficient scheme for handling multi-linked agent negotiations. With this scheme we attempt to overcome the drawbacks of sequential negotiations and negotiation parameter settings. Our approach is based on embedding a credit-based negotiation protocol within a local search scheduling algorithm. We demonstrate the computational efficiency and effectiveness of the approach in solving a real-life dynamic production scheduling problem which …

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Les For Wing Tip Vortex Around An Airfoil, Jiangang Cai Dec 2006

Les For Wing Tip Vortex Around An Airfoil, Jiangang Cai

Mathematics Dissertations

The wing tip vortex is very important because of its effects on the noise generation, blade/vortex interactions on helicopter blades, propeller cavitations on ships, and other fields. The objective of this work is to use the numerical simulation with high order accuracy and high resolution to investigate the formation and the near field evolution of a wing tip vortex at high Reynolds number. The computational domain includes a rectangular half-wing with a NACA 0012 airfoil section, a rounded wing tip and the surrounding boundaries. The wing has an aspect ratio of 0.75. The angle of attack is 10 degrees. The …

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Formal Analysis And Systematic Construction Of Two-Factor Authentication Scheme, Guomin Yang, Duncan S. Wong, Huaxiong Wang, Xiaotie Deng Dec 2006

Formal Analysis And Systematic Construction Of Two-Factor Authentication Scheme, Guomin Yang, Duncan S. Wong, Huaxiong Wang, Xiaotie Deng

Research Collection School Of Computing and Information Systems

One of the most commonly used two-factor authentication mechanisms is based on smart card and user’s password. Throughout the years, there have been many schemes proposed, but most of them have already been found flawed due to the lack of formal security analysis. On the cryptanalysis of this type of schemes, in this paper, we further review two recently proposed schemes and show that their security claims are invalid. To address the current issue, we propose a new and simplified property set and a formal adversarial model for analyzing the security of this type of schemes. We believe that the …

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Plans As Products Of Learning, Samin Karim, Budhitama Subagdja, Liz Sonenberg Dec 2006

Plans As Products Of Learning, Samin Karim, Budhitama Subagdja, Liz Sonenberg

Research Collection School Of Computing and Information Systems

This paper presents motivations and current related work in the field of plan learning. Additionally, two approaches that achieve plan learning are presented. The two presented approaches are centred on the BDI framework of agency and have particular focus on plans, which, alongside goals, are the means to fulfil intentions in most pragmatic and theoretical realisations of the BDI framework. The first approach is a hybrid architecture that combines a BDI plan extractor and executor with a generic low-level learner. The second approach uses hypotheses to suggest incremental refinements of a priori plans. Both approaches achieve plan generation that is …

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Online Advertising By The Comparison Challenge Approach, Jae Wong Lee, Jae Kyu Lee Dec 2006

Online Advertising By The Comparison Challenge Approach, Jae Wong Lee, Jae Kyu Lee

Research Collection School Of Computing and Information Systems

To enhance the effectiveness of online comparisons from a manufacturer's point of view, we develop a framework for the comparison challenge approach. To develop the comparison challenge framework, we analyze 12 factors that determine the characteristics of comparison and propose models of valuable comparison challenges using the CompareMe and CompareThem strategies. We demonstrate the approaches with the example of PC selection. To help plan the comparison challenges, we formulate a mathematical programming model that maximizes the total value of comparison under the constraints of comparison opportunity and budgetary limitation. The model is applied to eight comparison scenarios, and its performance …

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Towards Effective Content-Based Music Retrieval With Multiple Acoustic Feature Composition, Jialie Shen, John Shepherd, Ngu Ahh Dec 2006

Towards Effective Content-Based Music Retrieval With Multiple Acoustic Feature Composition, Jialie Shen, John Shepherd, Ngu Ahh

Research Collection School Of Computing and Information Systems

In this paper, we present a new approach to constructing music descriptors to support efficient content-based music retrieval and classification. The system applies multiple musical properties combined with a hybrid architecture based on principal component analysis (PCA) and a multilayer perceptron neural network. This architecture enables straightforward incorporation of multiple musical feature vectors, based on properties such as timbral texture, pitch, and rhythm structure, into a single low-dimensioned vector that is more effective for classification than the larger individual feature vectors. The use of supervised training enables incorporation of human musical perception that further enhances the classification process. We compare …

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