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Articles 331 - 360 of 666

Full-Text Articles in Computer Sciences

Performance Evaluation Of Matrix Operations On Map-Reduce Query Language, Ahmed Abdul Hameed A Ulde May 2016

Performance Evaluation Of Matrix Operations On Map-Reduce Query Language, Ahmed Abdul Hameed A Ulde

Computer Science and Engineering Theses - Archive

Non-Negative matrix factorization is well-known complex machine learning algorithm which is also used in collaborative filtering. Collaborative filtering technique is used in recommendation systems and these techniques aim at predicting the missing values in user-item association matrix. User-item association matrix contains number of users as rows and number of movies as columns and the values are the ratings given by user to respective movies. These matrices have large dimensions, missing values and needs parallel processing. Map reduce query language (MRQL) is a query processing and optimization system for large-scale, distributed data analysis, built on top of Apache hadoop, spark, hama …

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Spatio-Temporal Patterns Of Gps Trajectories Using Association Rule Mining, Vivek Kumar Sharma May 2016

Spatio-Temporal Patterns Of Gps Trajectories Using Association Rule Mining, Vivek Kumar Sharma

Computer Science and Engineering Theses - Archive

The availability of location-tracking devices such as GPS, Cellular Networks and other devices provides the facility to log a person or device locations automatically. This creates spatio-temporal datasets of user's movement with features like latitude,longitude of a particular location on a specific day and time. With the help of these features different patterns of user movement can be collected,queues and analyzed.In this research work, we are focused on user's movement patterns and frequent movements of users on a particular place,day or time interval. To achieve this we used Association Rule mining concept based on Apriori algorithm to find interesting movement …

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Processing Queries Over Partitioned Graph Databases: An Approach And It's Evaluation, Jay Dilipbhai D. Bodra May 2016

Processing Queries Over Partitioned Graph Databases: An Approach And It's Evaluation, Jay Dilipbhai D. Bodra

Computer Science and Engineering Theses - Archive

Representation of structured data using graphs is meaningful for applications such as road and social networks. With the increase in the size of graph databases, querying them to retrieve desired information poses challenges in terms of query representation and scalability. Independently, querying and graph partitioning have been researched in the literature. However, to the best of our knowledge, there is no effective scalable approach for querying graph databases using partitioning schemes. Also, it will be useful to analyze the quality of partitioning schemes from the query processing perspective. In this thesis, we propose a divide and conquer approach to process …

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Localization And Control Of Distributed Mobile Robots With The Microsoft Kinect And Starl, Nathan Hervey May 2016

Localization And Control Of Distributed Mobile Robots With The Microsoft Kinect And Starl, Nathan Hervey

Computer Science and Engineering Theses - Archive

With the increasing availability of mobile robotic platforms, interest in swarm robotics has been growing rapidly. The coordinated effort of many robots has the potential to perform a myriad of useful and possibly dangerous tasks, including search and rescue missions, mapping of hostile environments, and military operations. However, more research is needed before these types of capabilities can be fully realized. In a laboratory setting, a localization system is typically required to track robots, but most available systems are expensive and require tedious calibration. Additionally, dynamical models of the robots are needed to develop suitable control methods, and software must …

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Adwire: Add-On For Web Item Review System, Rajeshkumar Ganesh Kannapalli May 2016

Adwire: Add-On For Web Item Review System, Rajeshkumar Ganesh Kannapalli

Computer Science and Engineering Theses - Archive

Past few decades have seen a widespread use and popularity of online review sites such as Yelp, TripAdvisor, etc. As many users depend upon reviews before deciding upon a product, businesses of all types are motivated to possess an expansive arsenal of user feedback (preferably positive) in order to mark their reputation and presence in the Web (e.g., Amazon customer reviews). In spite of the fact that a huge extent of buying choices today are driven by numeric scores (e.g., movie rating in IMDB), detailed reviews play an important role for activities like purchasing an expensive mobile phone, DSLR camera, …

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A Data Driven, Hospital Quality Of Care Portal For The Patient Community, Sreehari Balakrishna Hegden May 2016

A Data Driven, Hospital Quality Of Care Portal For The Patient Community, Sreehari Balakrishna Hegden

Computer Science and Engineering Theses - Archive

With the recent changes in health services provision, patients are members of a consumer driven health care system. However, the health care consumers are not presented with adequate opportunities to enhance their position in choosing high quality hospital services. As a result, the demand for active patient participation in the choice of quality and safe hospital services remained unaddressed. In this research work, we developed MediQoC (Medicare Quality of Care), a data driven web portal for Medicare patients, their caregivers and the health care insurance policy designers to grant access to data-driven information about hospitals, and quality of care indicators. …

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A New Real-Time Approach For Website Phishing Detection Based On Visual Similarity, Omid Asudeh May 2016

A New Real-Time Approach For Website Phishing Detection Based On Visual Similarity, Omid Asudeh

Computer Science and Engineering Theses - Archive

Phishing attacks cause billions of dollars of loss every year worldwide. Among several solutions proposed for this type of attack, visual similarity detection methods have a good amount of accuracy. These methods exploit the fact that malicious pages mostly imitate some visual signals in the targeted websites. Visual similarity detection methods usually look for the imitations between the screen-shots of the web-pages and the image database of the most targeted websites. Despite their accuracy, the existing visual based approaches are not practical for the real-time purposes because of their image processing overhead. In this work, we use a pipeline framework …

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Fault Localization Based On Combinatorial Testing, Laleh Shikh Gholamhosseinghandehari May 2016

Fault Localization Based On Combinatorial Testing, Laleh Shikh Gholamhosseinghandehari

Computer Science and Engineering Dissertations - Archive

Combinatorial testing is a software testing strategy that has received a significant amount of attention from academia and industry. After executing a combinatorial test set, the execution status, i.e., pass or fail, of each test is obtained. If there is one or more failed tests, the next task is fault localization, i.e. localizing the fault in the source code. This dissertation addresses the problem of how to perform fault localization by leveraging the result of combinatorial testing. The major contribution of this dissertation is a fault localization approach called BEN that consists of two major phases: 1) failure-inducing combination identification, …

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Towards Better Usability Of Query Systems For Massive Ultra-Heterogeneous Graphs: Novel Approaches Of Query Formulation And Query Specification, Nandish Jayaram May 2016

Towards Better Usability Of Query Systems For Massive Ultra-Heterogeneous Graphs: Novel Approaches Of Query Formulation And Query Specification, Nandish Jayaram

Computer Science and Engineering Dissertations - Archive

There is a pressing need to tackle the usability challenges in querying massive, ultraheterogeneous entity graphs which use thousands of node and edge types in recording millions to billions of entities (persons, products, organizations) and their relationships. Widely known instances of such graphs include Freebase, DBpedia and YAGO. Applications in a variety of domains are tapping into such graphs for richer semantics and better intelligence. Both data workers and application developers are often overwhelmed by the daunting task of understanding and querying these data, due to their sheer size and complexity. To retrieve data from graph databases, the norm is …

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A Game Theoretic Framework For Temporal And Agent Abstractions In Multiagent Learning, Danielle Clement May 2016

A Game Theoretic Framework For Temporal And Agent Abstractions In Multiagent Learning, Danielle Clement

Computer Science and Engineering Dissertations - Archive

A major challenge in the area of multiagent reinforcement learning is addressing the issue of scale as systems get more and more complex. Systems with multiple agents attempting to explore and learn about the world they inhabit concurrently require more time and resources to learn optimal responses. Increasing the number of agents within a system dramatically increases the cost to represent the problem and calculate the solution. Single agent systems address part of the scaling problem through the use of temporal abstractions, or mechanisms to consider a sequence of many actions as a single temporal “step”. This concept has been …

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The Impact Of Cues And User Interaction On The Memorability Of System-Assigned Random Passwords, Mahdi Nasrullah Al Ameen May 2016

The Impact Of Cues And User Interaction On The Memorability Of System-Assigned Random Passwords, Mahdi Nasrullah Al Ameen

Computer Science and Engineering Dissertations - Archive

Given the choice, users produce passwords reflecting common strategies and patterns that ease recall but offer uncertain and often weak security. Addressing this usability-security tension in user authentication remains the key research issue in password studies for decades. In this thesis, we aim to understand how humans' cognitive abilities could be leveraged to design more secure and memorable authentication schemes. To achieve this goal, we draw upon multiple theories from cognitive psychology and implement them in the context of improving memorability for system-assigned random passwords. We argue that while the system assigns random passwords, it should also help users with …

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Detecting Real-Time Check-Worthy Factual Claims In Tweets Related To U.S. Politics, Fatma Dogan Dec 2015

Detecting Real-Time Check-Worthy Factual Claims In Tweets Related To U.S. Politics, Fatma Dogan

Computer Science and Engineering Theses - Archive

In increasing democracy and improving political discourse, political fact-checking has come to be a necessity. While politicians make claims about facts all the time, journalists and fact-checkers oftentimes reveal them as false, exaggerated, or misleading. Use of technology and social media tools such as Facebook and Twitter has rapidly increased the spread of misinformation. Thus, human fact-checkers face difficulty in keeping up with a massive amount of claims, and falsehoods frequently outpace truths. All U.S. politicians have successively adopted Twitter, and they make use of Twitter for a wide variety of purposes, a great example being making claims to enhance …

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Qp-Subdue: Processing Queries Over Graph Databases, Ankur Goyal Dec 2015

Qp-Subdue: Processing Queries Over Graph Databases, Ankur Goyal

Computer Science and Engineering Theses - Archive

Graphs have become one of the preferred ways to store structured data for various applications such as social network graphs, complex molecular structure, etc. Proliferation of graph databases has resulted in a growing need for effective querying methods to retrieve desired information. Querying has been widely studied in relational databases where the query optimizer finds a sequence of query execution steps (or plans) for efficient execution of the given query. Until now, most of the work on graph databases has concentrated on mining. For querying graph databases, users have to either learn a graph query language for posing their queries …

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Lung Cancer Subtype Classification From Whole Slide Histopathological Images, Dheeraj Ganti Dec 2015

Lung Cancer Subtype Classification From Whole Slide Histopathological Images, Dheeraj Ganti

Computer Science and Engineering Theses - Archive

Lung Cancer is one of the most serious diseases causing death for human be- ings. The progression of the disease and response to treatment di ers widely among patients. Thus it is very important to classify the type of tumor and also able to predict the clinical outcomes of patients. Majority of lung cancers is Non-Small Cell Lung Cancer (NSCLC) which constitutes of 84 % of all the type of lung cancers. The two major subtypes of NSCLC are Adenocarcinoma (ADC) and Squamous Cell Car- cinoma (SCC). Accurate classi cation of the lung cancer as NSCLC and its subtype classi …

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Quantitative Analysis Of Scalable Nosql Databases, Surya Narayanan Swaminathan Dec 2015

Quantitative Analysis Of Scalable Nosql Databases, Surya Narayanan Swaminathan

Computer Science and Engineering Theses - Archive

NoSQL databases are rapidly becoming the customary data platform for big data applications. These databases are emerging as a gateway for more alternative approaches outside traditional relational databases and are characterized by efficient horizontal scalability, schema-less approach to data modeling, high performance data access, and limited querying capabilities. The lack of transactional semantics among NoSQL databases has made the application determine the choice of a particular con- sistency model. Therefore, it is essential to examine methodically, and in detail, the performance of different databases under different workload conditions. In this work, three of the most commonly used NoSQL databases: MongoDB, …

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Speaker Identification In Live Events Using Twitter, Minumol Joseph Dec 2015

Speaker Identification In Live Events Using Twitter, Minumol Joseph

Computer Science and Engineering Theses - Archive

The prevalence of social media has given rise to a new research area. Data from social media is now being used in research to gather deeper insights into many different fields. Twitter is one of the most popular microblogging websites. Users express themselves on a variety of different topics in 140 characters or less. Oftentimes, users “tweet” about issues and subjects that are gaining in popularity, a great example being politics. Any development in politics frequently results in a tweet of some form. The research which follows focuses on identifying a speaker’s name at a live event by collecting and …

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Interactive Dashboard For User Activity Using Network Flow Data, Lalit Kumar Naidu Dec 2015

Interactive Dashboard For User Activity Using Network Flow Data, Lalit Kumar Naidu

Computer Science and Engineering Theses - Archive

Data visualization is critical in analytical systems containing multi-dimensional dataset and problems associated with increasing data size. It facilitates the data explanation process of reasoning data and discovering trends with visual perception that are otherwise not evident within the data in its raw form. The challenge involved in visualization is presenting data in such a way that helps end users in the process of information discovery with simple visuals. Interactive visualizations have increasingly become popular in recent years with prominent research in the field of information visualization. These techniques are heavily used in web-based applications to present myriad forms of …

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Performance Comparison Of Spatial Indexing Structures For Different Query Types, Neelabh Pant Jan 2015

Performance Comparison Of Spatial Indexing Structures For Different Query Types, Neelabh Pant

Computer Science and Engineering Theses - Archive

R-Trees are among the most popular multidimensional access methods suitable for indexing two dimensional spatial data and point data. R-Trees are found in most of the spatial database systems for indexing the spatial data. The data include points, lines and polygons which are retrieved and stored efficiently. There are many Spatial Database Systems which have incorporated R-Trees, for example, IBM Informix, Oracle Spatial, PostgreSQL and many others.Another version of R-Tree is R*-Tree which is also used for the same purpose i.e. indexing spatial data. R*-Tree has also been incorporated in an open source software SQLite with an extension of Spatialite. …

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Evaluating The Effectiveness Of Ben In Localizing Different Types Of Software Fault, Jaganmohan Chandrasekaran Jan 2015

Evaluating The Effectiveness Of Ben In Localizing Different Types Of Software Fault, Jaganmohan Chandrasekaran

Computer Science and Engineering Theses - Archive

Debugging refers to the activity of locating software faults in a program and is considered to be one of the most challenging tasks during software development. Automated fault localization tools have been developed to reduce the amount of effort and time software developers have to spend on debugging. In this thesis, we evaluate the effectiveness of a fault localization tool called BEN in locating different types of software faults. Assuming that combinatorial testing has been performed on the subject program, BEN leverages the result obtained from combinatorial testing to perform fault localization. Our evaluation focuses on how the following three …

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Sparse Representation Based Classification: Towards Efficiency And Accuracy, Soheil Shafiee Jan 2015

Sparse Representation Based Classification: Towards Efficiency And Accuracy, Soheil Shafiee

Computer Science and Engineering Dissertations - Archive

With the fast growing deployment of machine intelligence in several real-life applications, there are always increasing needs for faster and more precise machine learning algorithms, especially classification and object recognition. One of the most recent methods proposed for this purpose is Sparse Representation-based Classification (SRC) which works based on the emerging theory of Compressive Sensing. SRC shows excellent classification results in comparison to many well-known classification approaches. However, despite its high recognition power, SRC suffers from high computational and memory costs as it directly uses all original ground truth data as representatives to build its training model. Given high recognition …

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Design And Analysis Of Place-Based Opportunistic Networks, Yanliang Liu Jan 2015

Design And Analysis Of Place-Based Opportunistic Networks, Yanliang Liu

Computer Science and Engineering Dissertations - Archive

The swift growth and popularization of wireless technology and mobile smart phones have unfolded various opportunities and challenges before researchers' eyes. Opportunistic networks is one of the interesting and challenging topics. Generally speaking, opportunistic networks exploit the potential capability of existing mobile devices carried by people to provide pervasive computing service, such as data forwarding, without pre-planted infrastructures. The movement of mobile devices introduced by human activity plays a crucial role in the functionality of opportunistic networks, since it influences the contacts between different mobile devices. It is wellknown that human movement presents these place-centered features: intermittent hops between places …

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Tools For Program Understanding And Reverse-Engineering Of Mobile Applications, Tuan Anh Nguyen Jan 2015

Tools For Program Understanding And Reverse-Engineering Of Mobile Applications, Tuan Anh Nguyen

Computer Science and Engineering Dissertations - Archive

Mobile software development is evolving rapidly. Software development includes computer programing, documenting, testing and bug fixing processes. These processes need a detail understanding of the application logic which often requires reverse-engineering their artifacts. My thesis identifies and addresses the following three problems in mobile software development, specifically in program understanding and reverse-engineering for mobile application development. (1) There is no graphical on-phone debugger. (2) The second problem is that mobile software programmers have to manually re-implement the conceptual screen drawings or sketches of graphical artists in code, which is cumbersome and expensive. (3) Companies try to “go mobile” (by developing …

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Human Factors In Textual Password-Based Authentication, S M Taiabul Haque Jan 2015

Human Factors In Textual Password-Based Authentication, S M Taiabul Haque

Computer Science and Engineering Dissertations - Archive

Despite being the most commonly used method of authentication on the Web, textual password-based authentication is by no means a panacea as long as usability is concerned. In this dissertation work, we address some usability issues of textual password-based authentication and propose solutions to them. In our first work, we examine the problem of multiple password management and identify the mental model of users for managing multiple password-protected accounts. We propose a hierarchy of password importance and use an experiment to examine the degree ofsimilarity between passwords for lower-level (e.g. news portal) and higher-level (e.g. banking) websites in this hierarchy. …

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Simultaneous Optimization Of Performance, Energy, And Temperature While Allocating Tasks To Multi-Cores, Hafiz Fahad Sheikh Jan 2015

Simultaneous Optimization Of Performance, Energy, And Temperature While Allocating Tasks To Multi-Cores, Hafiz Fahad Sheikh

Computer Science and Engineering Dissertations - Archive

Multi-core processors have emerged as a solution to the problem of ever-increasing demands for computing power. However, higher power dissipation levels resulting into thermal problems and increasing cooling costs are major factors limiting their scalability into larger systems. Therefore, dynamic thermal management (DTM) and dynamic power management (DPM) of multi/many-core systems have emerged as important areas of research. The existing resource management approaches are either energy-aware or thermal-aware. In this dissertation, we focus on a new problem of simultaneous performance (P), energy (E), and temperature (T) optimized scheduling (PETOS) for allocating tasks to multi-core systems. To allocate a set of …

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The Impact Of Different Cues On The Memorability Of System-Assigned Recognition-Based Textual Passwords, Kanis Fatema Jan 2015

The Impact Of Different Cues On The Memorability Of System-Assigned Recognition-Based Textual Passwords, Kanis Fatema

Computer Science and Engineering Theses - Archive

To ensure memorability, users employ predictable patterns when creating new passwords. These patterns make passwords easy to guess, which not only increases risks to users but also for the entire system. In contrast, system-assigned textual passwords offer security but suffer from poor memorability. Previous research investigated the idea of textual recognition, in which the user would be assigned a word from a list and asked to recall the word later. The recall rate for this scheme was shown to be no better than memorizing a sequence of randomly assigned letters, but the researchers suggested that memorability may be improved if …

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Enabling Exploratory Mining Over Hidden Databases, Saravanan Thirumuruganathan Jan 2015

Enabling Exploratory Mining Over Hidden Databases, Saravanan Thirumuruganathan

Computer Science and Engineering Dissertations - Archive

Almost all popular websites (such as Amazon, EBay, microblogs such as Twitter, Instagram, collaborative content sites such as IMDB, Yelp etc) are powered internally by large data repositories. We designate them as hidden databases as their underlying data is accessible only through proprietary form-like interfaces that require users to query the system by entering desired values for a few attributes. Further, these web databases also impose a number of restrictions. For example, the top-k output constraint ensures that when there are a large number of tuples matching the query, only a few of them (top-k) are preferentially selected and returned …

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Methods For Large-Scale Machine Learning And Computer Vision, Yeqing Li Jan 2015

Methods For Large-Scale Machine Learning And Computer Vision, Yeqing Li

Computer Science and Engineering Dissertations - Archive

With the advance of the Internet and information technology, nowadays people can easily collect and store tremendous amounts of data such as images and videos. Developing machine learning and computer vision to analysis and learn from the gigantic data sets is an interesting yet challenging problem. Inspired by the trend, this thesis focus on developing large-scale machine learning and computer vision techniques for the purpose of handling various kinds of problems on gigantic data sets. With respect to the problem of image classification, we employ the technique of sub-selection, which uses partial observations to efficiently approximate the original high dimensional …

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Biomedical Parameter Measurements Using Video Processing, Negar Ziaee Nasrabadi Jan 2015

Biomedical Parameter Measurements Using Video Processing, Negar Ziaee Nasrabadi

Computer Science and Engineering Theses - Archive

For quite some time, patients’ cardiovascular parameters have been measured by sensors connected to their body. One way of measuring these parameters is pulse oximetry by using an optical technique. It uses a photodetector to detect light absorption changes of red and infrared light. These two types of light serve as two sources of illumination. These current types of methods for monitoring parameters are often viewed as uncomfortable by the patient, and therefore are not desirable for frequent and long periods of monitoring. Furthermore, these methods can potentially produce a psychologically influenced bias from the patient because the patient is …

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Advanced Sparsity Techniques In Medical Imaging And Image Processing, Chen Chen Jan 2015

Advanced Sparsity Techniques In Medical Imaging And Image Processing, Chen Chen

Computer Science and Engineering Theses - Archive

In the past decades, sparsity techniques has been widely applied in the fields of medical imaging, computer vision, image processing, compressive sensing, machine learning etc., and gained great success. In this work, we propose new models of sparsity techniques, which is an extension to the standard sparsity used in the existing works and in the vein of structure sparsity families. First, we introduce the wavelet tree sparsity in natural images. It shows that the tree sparsity regularization often outperforms the existing standard sparsity based techniques in magnetic resonance imaging. Second, we extend the tree sparsity to forest sparsity on multi-channel …

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Gait Analysis On A Smart Floor For Health Monitoring, Oluwatosin Oluwadare Jan 2015

Gait Analysis On A Smart Floor For Health Monitoring, Oluwatosin Oluwadare

Computer Science and Engineering Theses - Archive

Gait analysis is the investigation of an individual pattern of walking. Based on studies in Psychophysics, it has been shown that the human gait contains unique information that is useful for the evaluation of foot and gait pathologies. The goal of this project is to use a floor mounted pressure sensor system capable of measuring a significant number of parameters relevant to gait to predict and detect anomalous behavior. The system consists of an array of pressure sensors mounted under floor tiles and computer hardware responsible for data collection. The method used in this project is unique since most systems …

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