2,120 research outputs found

    A Temporal Framework for Hypergame Analysis of Cyber Physical Systems in Contested Environments

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    Game theory is used to model conflicts between one or more players over resources. It offers players a way to reason, allowing rationale for selecting strategies that avoid the worst outcome. Game theory lacks the ability to incorporate advantages one player may have over another player. A meta-game, known as a hypergame, occurs when one player does not know or fully understand all the strategies of a game. Hypergame theory builds upon the utility of game theory by allowing a player to outmaneuver an opponent, thus obtaining a more preferred outcome with higher utility. Recent work in hypergame theory has focused on normal form static games that lack the ability to encode several realistic strategies. One example of this is when a player’s available actions in the future is dependent on his selection in the past. This work presents a temporal framework for hypergame models. This framework is the first application of temporal logic to hypergames and provides a more flexible modeling for domain experts. With this new framework for hypergames, the concepts of trust, distrust, mistrust, and deception are formalized. While past literature references deception in hypergame research, this work is the first to formalize the definition for hypergames. As a demonstration of the new temporal framework for hypergames, it is applied to classical game theoretical examples, as well as a complex supervisory control and data acquisition (SCADA) network temporal hypergame. The SCADA network is an example includes actions that have a temporal dependency, where a choice in the first round affects what decisions can be made in the later round of the game. The demonstration results show that the framework is a realistic and flexible modeling method for a variety of applications

    Accelerating Malware Detection via a Graphics Processing Unit

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    Real-time malware analysis requires processing large amounts of data storage to look for suspicious files. This is a time consuming process that (requires a large amount of processing power) often affecting other applications running on a personal computer. This research investigates the viability of using Graphic Processing Units (GPUs), present in many personal computers, to distribute the workload normally processed by the standard Central Processing Unit (CPU). Three experiments are conducted using an industry standard GPU, the NVIDIA GeForce 9500 GT card. The goal of the first experiment is to find the optimal number of threads per block for calculating MD5 file hash. The goal of the second experiment is to find the optimal number of threads per block for searching an MD5 hash database for matches. In the third experiment, the size of the executable, executable type (benign or malicious), and processing hardware are varied in a full factorial experimental design. The experiment records if the file is benign or malicious and measure the time required to identify the executable. This information can be used to analyze the performance of GPU hardware against CPU hardware. Experimental results show that a GPU can calculate a MD5 signature hash and scan a database of malicious signatures 82% faster than a CPU for files between 0 96 kB. If the file size is increased to 97 - 192 kB the GPU is 85% faster than the CPU. This demonstrates that the GPU can provide a greater performance increase over a CPU. These results could help achieve faster anti-malware products, faster network intrusion detection system response times, and faster firewall applications

    Framing of the Texas Snowstorm on Twitter

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    This study investigates Framing Theory as it pertains to Twitter as the modern social sphere for communication and acquisition of news. There isn’t much work examining how the news frames the cause of global climate change on Twitter. This paper aims to study how five notable news publishers of different media political biases communicate through Twitter about the Texas Snowstorm that occurred in February, 2021. Through a content analysis of 119 tweets regarding a climate change induced storm of record-breaking, freezing temperatures; this study reveals the news’s fixation on the effects of the issue instead of the causes

    Detection of cystic structures using pulsed ultrasonically induced resonant cavitation

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    Apparatus and method for early detection of cystic structures indicative of ovarian and breast cancers uses ultrasonic wave energy at a unique resonance frequency for inducing cavitation in cystic fluid characteristic of cystic structures in the ovaries associated with ovarian cancer, and in cystic structures in the breast associated with breast cancer. Induced cavitation bubbles in the cystic fluid implode, creating implosion waves which are detected by ultrasonic receiving transducers attached to the abdomen of the patient. Triangulation of the ultrasonic receiving transducers enables the received signals to be processed and analyzed to identify the location and structure of the cyst

    Vapor Compression Distillation Subsystem (VCDS) component enhancement, testing and expert fault diagnostics development, volume 1

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    Vapor compression distillation technology for phase change recovery of potable water from wastewater has evolved as a technically mature approach for use aboard the Space Station. A program to parametrically test an advanced preprototype Vapor Compression Distillation Subsystem (VCDS) was completed during 1985 and 1986. In parallel with parametric testing, a hardware improvement program was initiated to test the feasibility of incorporating several key improvements into the advanced preprototype VCDS following initial parametric tests. Specific areas of improvement included long-life, self-lubricated bearings, a lightweight, highly-efficient compressor, and a long-life magnetic drive. With the exception of the self-lubricated bearings, these improvements are incorporated. The advanced preprototype VCDS was designed to reclaim 95 percent of the available wastewater at a nominal water recovery rate of 1.36 kg/h achieved at a solids concentration of 2.3 percent and 308 K condenser temperature. While this performance was maintained for the initial testing, a 300 percent improvement in water production rate with a corresponding lower specific energy was achieved following incorporation of the improvements. Testing involved the characterization of key VCDS performance factors as a function of recycle loop solids concentration, distillation unit temperature and fluids pump speed. The objective of this effort was to expand the VCDS data base to enable defining optimum performance characteristics for flight hardware development

    Land Cover And Landscape Composition Change Of The Caatinga: A Case Study From São Francisco Valley Area

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    Land use change impacts range from collective global climate effects to local degradation of ecosystem services available to humans. Consequently, understanding regional land use change has many ramifications. In northeastern Brazil, the caatinga, a semi-arid scrub vegetation rich in endemic species, has undergone extensive area loss and degradation due to increasing human populations, expansion of agriculture due to growth in irrigation, and recently infrastructure development for inter-basin transfer of water to support economic development. This research focuses on land use change of caatinga in Pernambuco State and North Central Bahia State along the São Francisco River. Landsat imagery from 1989 to 2008 is used to (1) detect the degree and direction of land use change, and (2) quantify changes in landscape structure, and (3) examine spatial variation in landscape structural changes. Change analysis highlights the loss of caatinga vegetation cover, especially along the São Francisco River where irrigation and urban cover expanded both along andfurther away from the river. Transformation of landscape composition and structure varies from extensive coalescence of agriculture along the river, to increased spatial complexity and caatinga fragmentation further from the river, to spatially localized fragmentation of caatinga vegetation even further from the river

    Comparative analysis of the effect of tricalcium silicate cement and mineral trioxide aggregate on the cellular composition of the pulp after the vital amputation in experimental animals.

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    The purpose of the study was to determine the effect of tricalcium silicate cement on the protective process of pulp in the treatment of reversible pulpitis. There was carried out an experiment on 3-month-old male rabbits to study  morphofunctional changes in the pulp tissue with modeling of reversible pulpitis followed by vital amputation with coating of the pulp with tricalcium silicate (8 animals, study group) and mineral trioxide aggregate (MTA) (8 animals, comparison group). In 2 and 6 weeks dental tissues were fixed by 10% formalin solution and after decalcification and done routine procedures, histological sections were made, stained with hematoxylin and eosin. After the application of tricalcium silicate cement in 2 weeks, the odontoblast density changed to 3.92±1.03×103/mm2 from 8.3±1.02×103/mm2 of cell density in the intact group. The number of neutrophils also plays a big role in the regeneration of inflamed pulp. Thus, in 2 weeks the number of neutrophils made up 6.39±2.61x102 per 1 mm2, which is 3 times less than after mineral trioxide aggregate usage – 19.49±2.85x102per 1 mm2. It was established that the processes of rheological disorders with impaired lymph circulation are replaced by the restoration of the cellular component. In such a way the proposed vital amputation was examined for reversible pulpitis and it revealed similar clinical and pathological effectiveness with a positive regenerative process with formation of a sufficient number of odontoblasts (7.98±1.51×103/mm2) for the subsequent formation of a hard tissue bridge, which consists of collagen fibers in the form of a frame. The main goal of vital amputation procedure is regeneration (proliferation) of the pulp with a short-term signs of alteration and exudation, which is provided by the choice of material for the pulp covering. Thus, after the vital amputation of the pulp, followed by the use of tricalcium silicate cement 6 weeks after, the number of neutrophils was 1.39±0.72x102per 1 mm2, which is 5 times less than after using mineral trioxide aggregate

    When two worlds collide: A story about collaboration, witnessing and life story research with soldiers returning from war

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    The story we share here stems from our research with British military personnel who are adapting to life with a physical and/or psychological disability after serving in the Iraq or Afghanistan wars. Throughout our research, we have struggled to answer the kinds of questions that plague qualitative researchers: How might we gain insights into intense, traumatic, even life-changing experiences? Should we be inviting individuals to recount or revisit such potent moments from their lives? What interpretive framework might we draw on to make sense of what are sometimes senseless experiences? How can we share any ensuing understanding with others without diluting, diminishing or disrespecting the lives of soldiers or their families? The story we share here – which responds to Denzin’s (2003) challenge to reanimate life and Erickson’s (2010) provocation to do so with greater modesty, visibility, and reflexivity – offers one answer to these questions
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