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Articles 481 - 510 of 666

Full-Text Articles in Computer Sciences

Mimic: An Active Covert Channel That Evades Regularity-Based Detection, Kush Kothari Jan 2010

Mimic: An Active Covert Channel That Evades Regularity-Based Detection, Kush Kothari

Computer Science and Engineering Theses - Archive

A covert timing channel is a hidden communication channel based on network timing that an attacker can use to sneak secrets out of a secure system. Active covert channels, in which the attacker uses a program to automatically generate innocuous traffic to use as a medium for embedding the covert channel, are especially problematic, as they allow the attacker to output large amounts of secret data. A promising technique for detecting covert timing channels focuses on using entropy-based tests. This technique can reliably detect known covert timing channels by using a combination of entropy (EN) and conditional entropy (CE) to …

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Target Tracking With Lucas-Kanade Optical Flow And Particle Filters Through Affine Transforms And Occlusion, Justin Graham Jan 2010

Target Tracking With Lucas-Kanade Optical Flow And Particle Filters Through Affine Transforms And Occlusion, Justin Graham

Computer Science and Engineering Theses - Archive

This paper investigates a hybrid approach derived from Lucas-Kanade optical flow tracking and particle filters that is capable of tracking objects through occlusion and affine transformations. This approach is inspired by aircraft sensor pod infrared and electro-optical tracking applications. For aircraft based sensors, it is important that a tracking system be able to track through rotations as the aircraft orbits a targeting area. It is also of use to handle cases where the target may be momentarily occluded due to other vehicles or obstacles in the area. The main focus of this investigation is to find a technique that performs …

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A Framework For Real-Time Fault Detection And Response In Multi-Agent Teams, Matthew B. Middleton Jan 2010

A Framework For Real-Time Fault Detection And Response In Multi-Agent Teams, Matthew B. Middleton

Computer Science and Engineering Theses - Archive

This thesis details the creation of a fault detection and response framework that can be applied to mobile multi-agent teams. This framework unites existing concepts of conditioned based maintenance and real-time machine diagnostics with a high-level matrix based discrete event command and control system that can respond to detected mechanical faults in agents in real-time. This allows for automatic corrective actions to be taken when an agent experiences failure if redundant resources are available to replace the failed unit or for the mission planner to be notified that the mission is no longer achievable given the operating conditions of the …

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Real Time Hardware And Software Systems For Micro Air Vehicle Flight Control Testing, Christopher Dale Mcmurrough Jan 2010

Real Time Hardware And Software Systems For Micro Air Vehicle Flight Control Testing, Christopher Dale Mcmurrough

Computer Science and Engineering Theses - Archive

The trend of increasing capabilities of micro scale electrical, mechanical, and computing systems is opening up the possibilities of new unmanned vehicle platforms. Both unmanned aerial and ground vehicles have traditionally been created from large conventional platforms such as automobiles, rotorcraft, and fixed wing aircraft. These conventional chassis designs are durable and proven, but the benefits of automating these types of platforms are limited by their inherent human-centric design. Many real-world applications would benefit greatly from vehicle classes designed with unconventional means such as biologically inspired locomotion. Micro air vehicles are a class of vehicles that have recently began moving …

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Fast Jamming Detection In Wireless Sensor Networks, Kartik Siddhabathula Jan 2010

Fast Jamming Detection In Wireless Sensor Networks, Kartik Siddhabathula

Computer Science and Engineering Theses - Archive

Non-dedicated medium of communication for Wireless Sensor Networks (WSN) makes them vulnerable to jamming attack where an adversary injects strong signal or noises to interfere with the transmission and thus block the channel. In applications such as border security, people are particularly interested in the areas where the channel is currently jammed. It is therefore crucial to be able to detect the jamming attacks as fast as possible. Existing studies have shown that the most effective indicator of jamming attacks is the packet delivery ratio (PDR). However, current PDR-based schemes use end-to-end packet delivery ratio, which requires one to observe …

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Fast And Energy-Efficient Technique For Jammed Region Mapping In Wireless Sensor Networks, Nabila Rahman Jan 2010

Fast And Energy-Efficient Technique For Jammed Region Mapping In Wireless Sensor Networks, Nabila Rahman

Computer Science and Engineering Theses - Archive

Wireless sensor networks (WSNs) have great practical importance for surveillance systems to perform monitoring by acquiring and sending information about intrusions into a secured area. Very little human intervention is required for WSNs, which is one of the most desirable features of them and thus making them a cheaper and safer alternative for securing large area such as international borders. Jamming attacks in WSNs can be applied to disrupt communications among the sensor nodes in the network by barring the reception of wireless signals of the sensor nodes' transceivers. Since it is difficult to prevent jamming attacks, detection and mapping …

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Event Recognition From Ambient Assistive Living Technologies, Eric William Becker Jan 2010

Event Recognition From Ambient Assistive Living Technologies, Eric William Becker

Computer Science and Engineering Dissertations - Archive

As the population ages and technology advances, a need exists for creating ambient intelligent systems to be placed within the home environment. Attitudes towards technology have been changing, and home monitoring is now considered a less expensive and desirable alternative. Ideally, such systems should be small, wireless, and take the minimum of effort and cost to install and place within the home. In order to detect human activity in an assistive environment, key questions about the construction and operation of the technology and methods needed to detect that activity. To that end, a computational framework has been created inside an …

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Advanced Software Testing Techniques Based On Combinatorial Design, Wenhua Wang Jan 2010

Advanced Software Testing Techniques Based On Combinatorial Design, Wenhua Wang

Computer Science and Engineering Dissertations - Archive

Combinatorial testing refers to a testing strategy that applies the principles of combinatorial design to the domain of software test generation. Given a system with k parameters, combinatorial testing requires all the combinations involving t out of k parameters be covered at least once, where t is typically much smaller than k. The key insight behind combinatorial testing is that while the behavior of a system may be affected by many parameters, most faults are caused by interactions involving only a small number of parameters. Empirical studies have shown that combinatorial testing can dramatically reduce the number of tests while …

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Information-Driven Data Gathering In Wireless Sensor Networks, Jing Wang Jan 2010

Information-Driven Data Gathering In Wireless Sensor Networks, Jing Wang

Computer Science and Engineering Dissertations - Archive

Since the advance of wireless technology enables the mass production of low-cost, small-sized sensor nodes, sensor nodes can be densely deployed in an area for high tolerance to node failure or to achieve better coverage statistically. The redundancy of sensor nodes results in the temporal and spatial correlation of sensory data, which motivates the information-driven data gathering approaches for wireless sensor networks (WSNs).Since existing approaches target at the sensory data that are already highly correlated with each other, little attention has been paid to the idea of changing the sampling schedules of the sensor nodes to reduce the correlation among …

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Combating Dos Attacks In Wireless Networks Using Lightweight Key Mangement Schemes, Qi Dong Jan 2010

Combating Dos Attacks In Wireless Networks Using Lightweight Key Mangement Schemes, Qi Dong

Computer Science and Engineering Dissertations - Archive

The unique features of wireless networks lead to many attractive applications in both military and civilian operations. Wireles networking devices usually use batteries as power supply, which requires all the operations to be as efficient as possible. Since the resources such as the battery energy and wireless communication channels are critical in wireless networks, the attacker my try to disable the system operation by launching denial of service (DoS) attacks. Specifically, the attacker prevents the system from working by using up or blocking the limited resources.This dissertation includes three studies on security mechanisms to combat DoS attacks using lightweight key …

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Reinforcement Learning Based Strategies For Adaptive Wireless Sensor Network Management, Kunalbhai Shah Jan 2010

Reinforcement Learning Based Strategies For Adaptive Wireless Sensor Network Management, Kunalbhai Shah

Computer Science and Engineering Dissertations - Archive

In wireless sensor networks (WSN), resource-constrained nodes are expected to operate in highly dynamic and often unattended environments. WSN applications need to cope with such dynamicity and uncertainty intrinsic in sensor networks, while simultaneously trying to achieve efficient resource utilization. A middleware framework with support for autonomous, adaptive and distributed sensor management, can simplify development of such WSN applications. We present a reinforcement learning based WSN middleware framework to enable autonomous and adaptive applications with support for efficient resource management. The uniqueness of our framework lies in using a bottom-up approach where each sensor node is responsible for its resource …

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A Privacy Enhanced Situation-Aware Middleware Framework For Ubiquitous Computing Environments, Gautham V. Pallapa Jan 2009

A Privacy Enhanced Situation-Aware Middleware Framework For Ubiquitous Computing Environments, Gautham V. Pallapa

Computer Science and Engineering Dissertations - Archive

The Ubiquitous Computing paradigm integrates myriads of small, inexpensive, heterogeneous networked devices, including sensors, distributed throughout the environment, with the intent of enabling context awareness in systems deployed to monitor the environment. This is accomplished by monitoring events, such as access, or utilization of resources, and obtaining knowledge about user activities, and interactions with other entities in the environment. Existing context-aware systems predominantly encapsulate the occurred activities either by using Event-Condition-Action rules, where an instance of the event performs as a trigger, or by prediction mechanisms, such as Dynamic Bayesian Networks, which compute decisions, based on the information obtained. However, …

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Attributes Selection And Package Design To Maximize Visibility Of Objects, Md Zahiduzzaman Miah Jan 2009

Attributes Selection And Package Design To Maximize Visibility Of Objects, Md Zahiduzzaman Miah

Computer Science and Engineering Dissertations - Archive

In recent years, there has been significant interest in the development of ranking functions and efficient top-k retrieval algorithms to help users in ad-hoc search and retrieval in databases (e.g., buyers searching for products in a catalog). We introduce a complementary problem: how to guide a seller in selecting the best attributes of a new tuple (e.g., a new product) to highlight so that it stands out in the crowd of existing competitive products and is widely visible to the pool of potential buyers. For example, assume one wants to sell an iPod in e-commerce site, but the title allows …

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Energy Efficient Routing Structures And Wakeup Schemes For Wireless Sensor Networks, Byoung Lee Jan 2009

Energy Efficient Routing Structures And Wakeup Schemes For Wireless Sensor Networks, Byoung Lee

Computer Science and Engineering Dissertations - Archive

Wireless sensor networks, which consist of a large number of sensor nodes and a base station, are used for many applications aimed at collecting information. Each sensor node is equipped with a small amount of battery, limited memory, finite radio range and small CPU. It gathers required information and it sends the information to the base station. The large number of sensors can cover a large area by cooperating with each other to build a multi-hop wireless network. However, the small amount of battery is one of the critical concerns because sensor network life time depends on battery longevity. It …

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Enabling Context-Aware Applications In Smart Environments‏, Roman Arora Jan 2009

Enabling Context-Aware Applications In Smart Environments‏, Roman Arora

Computer Science and Engineering Theses - Archive

Recognizing human activities is an important feature for the development of contextaware applications that are so fundamental to enabling assistive environments. Only once these applications are able to determine the activities that their inhabitants are performing can they assist the individuals and their special needs. In order to do this, it is necessary to build models that can accurately capture and recognize the observed patterns. Equally important is the need to manage and distribute the information that has been inferred, and to provide Quality of Service (QoS) guarantees so that context-aware applications can react effectively to emergent situations. In this …

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Query Auditing Against Partial Disclosure, Mayur Motgi Jan 2009

Query Auditing Against Partial Disclosure, Mayur Motgi

Computer Science and Engineering Theses - Archive

Many government agencies, businesses, and nonprofit organizations need to collect, analyze, and report data about individuals in order to support their short-term and long-term planning activities. Statistical Databases therefore contain confidential information such as income, credit ratings, type of disease, or test scores of individuals. Such data are typically stored online and analyzed using sophisticated database management systems (DBMS) and software packages. On one hand, such database systems are expected to satisfy user requests of aggregate statistics related to non-confidential and confidential attributes. On the other hand, the system should be secure enough to guard against a user's ability to …

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Peon: Privacy-Enhanced Opportunistic Networks With Applications In Assistive Environments, Gauri Vakde Jan 2009

Peon: Privacy-Enhanced Opportunistic Networks With Applications In Assistive Environments, Gauri Vakde

Computer Science and Engineering Theses - Archive

Opportunistic Networking holds a great deal of potential for making communications easier and more flexible in pervasive assistive environments. However, security and privacy must be addressed to make these communications acceptable with respect to protecting patient privacy. We propose Privacy-Enhanced Opportunistic Networking (PEON), a system for using opportunistic networking in privacy-preserving way. PEON uses concepts from anonymous communications, re-routing messages through groups of peer nodes to hide the relation between the sources and destinations. We describe a set of protocols that explore a practical range of trade-offs between privacy and communication costs by modifying how closely the protocol adheres to …

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Web Application Integration Using Mashups, Ronda Hilton Jan 2009

Web Application Integration Using Mashups, Ronda Hilton

Computer Science and Engineering Theses - Archive

The HTML DOM is the W3C standard data model for HTML documents. A web page may be viewed as a tree structure with data nodes at each level, according to the HTML DOM, to enable web applications to access it dynamically. If a web page mashes up more than one web application, the data from one web application may flow as input into another. The user may manually transfer such data piecemeal by using the mouse to cut and paste the displayed text. Instead of this tedious and error-prone repetitious method of data transfer, the mashup may contain a software …

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Pseudo-Hierarchical Ant-Based Clustering Using A Heterogeneous Agent Hierarchy And Automatic Boundary Formation, Jeremy Bernard Brown Jan 2009

Pseudo-Hierarchical Ant-Based Clustering Using A Heterogeneous Agent Hierarchy And Automatic Boundary Formation, Jeremy Bernard Brown

Computer Science and Engineering Theses - Archive

The behavior and self-organization of ant colonies has been widely studied and served as the inspiration and source of many swarm intelligence models and related clustering algorithms. Unfortunately, most models that directly mimic ants produce too many clusters and converge too slowly. A wide range of research has attempted to address this issue through various means, but a number of problems remain: 1) Ants must still physically move from one cluster to another through intermediate locations, 2) current methods for remote relocation of an item only consider one movement at time to a particular location and do not consider patterns …

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An Auction Mechanism For Grid Scheduling And Resource Allocation In The Context Of Atlas, Tengkok Aaron Thor Jan 2009

An Auction Mechanism For Grid Scheduling And Resource Allocation In The Context Of Atlas, Tengkok Aaron Thor

Computer Science and Engineering Dissertations - Archive

The technological advancements in the areas of computing and networking over the recent years have led to an emerging infrastructure known as Computational Grids, which provides users with the flexibility of pervasive access to enormous computational resources hosted at remote locations. Effective resource management and job scheduling poses a challenge when constraints such as resource utilization, response time, global and local policies need to be taken into account, while dealing with potentially independent sources of jobs, computational, and storage resources. It must be ensured that scheduling decisions made are still valid by the time a job is to be executed, …

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Design And Analysis Of Application Architecture For Opportunistic Networks Using Ad Hoc Wi-Fi, Sankalp Vinod Shere Jan 2009

Design And Analysis Of Application Architecture For Opportunistic Networks Using Ad Hoc Wi-Fi, Sankalp Vinod Shere

Computer Science and Engineering Theses - Archive

In recent years, the number of smartphone users has increased by many folds. In fact, it is estimated to reach 100 million by 2013. Current generation of smartphones has better storage, battery, computing capabilities and they come equipped with short range communication technologies like Bluetooth and Wi-Fi. These improved capabilities coupled with staggering rise in number of users, has prompted growing interest in smartphone applications that help users to communicate with each other directly and over the internet. In particular as a result, when a large number of mobile users can communicate directly with each other during opportunistic contacts when …

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Reactive Control Composition For Mobile Manipulators, Binu George Mathew Jan 2009

Reactive Control Composition For Mobile Manipulators, Binu George Mathew

Computer Science and Engineering Theses - Archive

A mobile manipulator is a manipulator mounted on a mobile platform. Due to this combination it has increased mobility compared to a fixed manipulator and increased dexterity compared to a mobile platform. At the same time it has a significantly higher number of degrees of freedom than fixed manipulators or mobile platforms and an increased task and workspace. In particular, the size of the workspace of the manipulator is restricted only by the workspace limitations of the mobile platform and the obstacles around the goal location. In addition, the extra degrees of freedom increase the number of ways in which …

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Design And Analysis Of A Mobile File Sharing System For Opportunistic Networks, Gautam Ravendra Chavan Jan 2009

Design And Analysis Of A Mobile File Sharing System For Opportunistic Networks, Gautam Ravendra Chavan

Computer Science and Engineering Theses - Archive

In the past several years, wireless mobile devices with advanced computing, sensing, and storing capabilities have been increasingly developed by handset manufacturers, deployed by wireless carriers, and accepted by consumers. A prominent example is the vast success of Apple's iPhone, which witnessed a sale of 1 million units during the first 3 days of sales for its new version iPhone 3GS. As a result of the increasing popularity of these mobile devices, users can carry, utilize, and exchange information embedded therein, ideally wherever they go and whenever they want. A prominent scenario is where information is exchanged among users when …

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The Reputation System For Robust, Structured P2p Systems, Apurv Ashok Dhadphale Jan 2009

The Reputation System For Robust, Structured P2p Systems, Apurv Ashok Dhadphale

Computer Science and Engineering Theses - Archive

Structured peer-to-peer systems are distributed communication systems that typically use Distributed Hash Table (DHT) indexing to efficiently locate the resources. These networks are highly scalable and can route the messages correctly even for the extremely dynamic environment. But these networks are vulnerable; even a small fraction of malicious nodes can bias the lookup results when they are present on a lookup path. In our thesis, we address this problem of reliably searching the insecure p2p networks. We propose a reputation system to reduce the number of failed lookups and make the networks more robust. For our study, the concept is …

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Liquid: A Detection Resistant Covert Timing Channel Based On Ipd Shaping, Robert J. Walls Jan 2009

Liquid: A Detection Resistant Covert Timing Channel Based On Ipd Shaping, Robert J. Walls

Computer Science and Engineering Theses - Archive

Covert timing channels provide a way to surreptitiously leak information from an entity in a higher-security level to an entity in a lower level. The difficulty of detecting or eliminating such channels makes them a desirable choice for adversaries that value stealth over throughput. When one considers the possibility of such channels transmitting information across network boundaries, the threat becomes even more acute. A promising technique for detecting covert timing channels focuses on using entropy-based tests. This method is able to reliably detect known covert timing channels by using a combination of entropy and conditional entropy to detect anomalies in …

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An Integrated Framework For Qos-Aware Data Reporting In Wireless Sensor Networks, Hyun Jung Choe Jan 2009

An Integrated Framework For Qos-Aware Data Reporting In Wireless Sensor Networks, Hyun Jung Choe

Computer Science and Engineering Dissertations - Archive

Wireless sensor networks are being deployed in a wide variety of applications such as environment monitoring, smart buildings, security, machine surveillance system, and so on.The deployment of sensor networks for a specific sensing application enhances the ability to control and examine the physical environments while collecting meaningful information from the monitoring area.In densely deployed networks, the sensor nodes located in an adjacent area detect the targeted phenomena in its sensing range and report the gathered (raw or processed) data to designated sinks via single-hop or multi-hop communication paths.Although the correlation of data from proximity sensors cause overheads in terms of …

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Autonomous Abstraction Of Policies Based On Policy Homomorphism, Srividhya Rajendran Jan 2009

Autonomous Abstraction Of Policies Based On Policy Homomorphism, Srividhya Rajendran

Computer Science and Engineering Dissertations - Archive

A life long learning agent performing in a complex and dynamic environment needs the ability to learn increasingly complex tasks over time. These agents over their lifetime have to learn new tasks, adapt the policies of already learned tasks and extract and reuse the knowledge gained to learn new, more complex tasks. To do this, they need methods that allow them to autonomously extract knowledge from the already learned policy instances and reuse the knowledge gained to learn related tasks in novel environments.This dissertation presents a novel approach that enables an agent to autonomously abstract reusable skills and concepts using …

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Autonomic Trust Management In Dynamic Systems, Brent Lagesse Jan 2009

Autonomic Trust Management In Dynamic Systems, Brent Lagesse

Computer Science and Engineering Dissertations - Archive

Research in pervasive computing is aimed at creating environments where users can seamlessly benefit from ubiquitous computing resources despite the complexity of the environment. Providing security in such systems is a difficult task since traditional security mechanisms often require significant user attention and do not scale well to large, mobile, and open environments. To combat this problem, distributed trust has been proposed to provide security in pervasive systems. While much research has been performed in the area, many vulnerabilities and insufficiencies still exist, especially in mobile ad-hoc systems that cannot support distributed trust mechanisms requiring pre-existing infrastructure and cooperation. Dynamic …

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Subcellular Structure Modeling And Tracking For Cell Dynamics Study, Quan Wen Aug 2008

Subcellular Structure Modeling And Tracking For Cell Dynamics Study, Quan Wen

Computer Science and Engineering Dissertations - Archive

The introduction of sensitive and fast electronic imaging devices and the development of biological methods to tag proteins of interest by green fluorescent proteins (GFP) have made a full understanding of live cell dynamics achievable. With the latest hardware technology, such as high speed laser scanning confocal Microscopy (LSCM), it has now become critical to develop automatic quantitative data analysis tools to keep pace with and to fully exploit the functionalities of state-of-the-art hardware. One task of such tools is the motility analysis of subcellular structures. This dissertation provides a series of computational approaches for studying subcellular structure motility. Firstly, …

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Enhanced Bioinformatics Data Modeling Concepts And Their Use In Querying And Integration, Feng Ji Aug 2008

Enhanced Bioinformatics Data Modeling Concepts And Their Use In Querying And Integration, Feng Ji

Computer Science and Engineering Dissertations - Archive

In bioinformatics research, scientists usually face the problems of modeling complex data types and integrating diverse resources. Traditional data models such as EER lack the expressing power to capture many characteristics that are common in bioinformatics data. We first propose extensions to the ER model that allow accurate representation of many of these characteristics. We then utilize these concepts in an integrative system to provide an easy-to-use interface for biologists to construct queries. Our research utilizes the enhanced conceptual modeling concepts to create a prototype mediator for querying multiple data sources. The various relationships between different biological entities are all …

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