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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
521

Návrhové vzory v paralelních a distribuovaných systémech / Design Patterns for Parallel and Distributed Systems

Jurnečka, Peter Unknown Date (has links)
This Ph.D. thesis describes proposed notation and method for working with parallel design patterns, which allowes proposing of automatic corrections to existing parallel source code with help of refactoring. In order to define the proposed notation, this work must cover areas of static code analysis, formal description of parallel design patterns and refactoring. Static code analysis is used to analyse the existing parallel source code for definition of places where you want to insert specified design pattern. Formal description of design pattern allows you to automatically apply the pattern to the existing source code. Finally, refactoring allows you to edit an existing source code without changing its functionality. The first part is devoted to the description of the current status in these three areas e.g. code analysis, design patterns and refactoring. The second part is devoted to a description of the methodology and experimental verification of its deployment.
522

Analýza datových toků pro knihovny se složitými vzory interakcí / Data Lineage Analysis of Frameworks with Complex Interaction Patterns

Hýbl, Oskar January 2020 (has links)
Manta Flow is a tool for analyzing data flow in enterprise environment. It features Java scanner, a module using static analysis to determine the flows through Java applications. To analyze an application using some framework, the scanner requires a dedicated plugin. Although Java scanner provides plugins for several frameworks, to be usable for real applications, it is essential that the scanner supports as many frameworks as possible, which requires implementation of new plugins. Application using Apache Spark, a framework for cluster computing, are increasingly popular. Therefore we designed and implemented Java scanner plugin that allows the scanner to analyze Spark applications. As Spark focuses on data processing, this presented several challenges that were not encountered in other frameworks. In particular it was necessary to resolve the data schema in various scenarios and track the schema changes throughout any operations invoked on the data. Of the multiple APIs Spark provides for data processing, we focused on Spark SQL module, notably on Dataset, omitting the legacy RDD. We also implemented support for data access, covering JDBC and chosen file formats. The implementation has been thoroughly tested and is proven to work correctly as a part of Manta Flow, which features the plugin in...
523

High Performance Static Random Access Memory Design for Emerging Applications

Chen, Xiaowei January 2018 (has links)
Memory wall is becoming a more and more serious bottleneck of the processing speed of microprocessors. The mismatch between CPUs and memories has been increasing since three decades ago. SRAM was introduced as the bridge between the main memory and the CPU. SRAM is designed to be on the same die with CPU and stores temporary data and instructions that are to be processed by the CPU. Thus, the performance of SRAMs has a direct impact on the performance of CPUs. With the application of mass amount data to be processed nowadays, there is a great need for high-performance CPUs. Three dimensional CPUs and CPUs that are specifically designed for machine learning are gaining popularity. The objective of this work is to design high-performance SRAM for these two emerging applications. Firstly, a novel delay cell based on dummy TSV is proposed to replace traditional delay cells for better timing control. Secondly, a unique SRAM with novel architecture is custom designed for a high-performance machine learning processor. Post-layout simulation shows that the SRAM works well with the processing core and its design is optimized to work well with machine learning processors based on convolutional neural networks. A prototype of the SRAM is also tapped out to further verify our design.
524

Shepherding Network Security Protocols as They Transition to New Atmospheres: A New Paradigm in Network Protocol Analysis

Talkington, Gregory Joshua 12 1900 (has links)
The solutions presented in this dissertation describe a new paradigm in which we shepherd these network security protocols through atmosphere transitions, offering new ways to analyze and monitor the state of the protocol. The approach involves identifying a protocols transitional weaknesses through adaption of formal models, measuring the weakness as it exists in the wild by statically analyzing applications, and show how to use network traffic analysis to monitor protocol implementations going into the future. Throughout the effort, we follow the popular Open Authorization protocol in its attempts to apply its web-based roots to a mobile atmosphere. To pinpoint protocol deficiencies, we first adapt a well regarded formal analysis and show it insufficient in the characterization of mobile applications, tying its transitional weaknesses to implementation issues and delivering a reanalysis of the proof. We then measure the prevalence of this weakness by statically analyzing over 11,000 Android applications. While looking through source code, we develop new methods to find sensitive protocol information, overcome hurdles like obfuscation, and provide interfaces for later modeling, all while achieving a false positive rate of below 10 percent. We then use network analysis to detect and verify application implementations. By collecting network traffic from Android applications that use OAuth, we produce a set of metrics that when fed into machine learning classifiers, can identify if the OAuth implementation is correct. The challenges include encrypted network communication, heterogeneous device types, and the labeling of training data.
525

Optimalizace odhadu vzdálenosti v bezdrátové ad-hoc síti / Distance Estimation in Wireless Ad-hoc Network

Botta, Miroslav January 2011 (has links)
The work deals with processing of radio received signal strength in IEEE 802.15.4 which communicates in 2.4 GHz ISM band. The signal is processed by the three approximation methods. They are tested for their effectiveness for measuring in different radio environments. Furthermore, the work deals with calculation of the most efficient coefficients for distance calculating by radio transmission fucntions. It defines the issues of such solutions on practical examples. The work also deals with the experimental algorithm for implementing dynamic calibration of the coefficients. It describes the design, processing and verification of this system in practice.
526

Posouzení existující železobetonové konstrukce / Assessment of existing reinforced concrete structures

Pospíšil, Ondřej January 2014 (has links)
This master’s thesis is concerned with the static load capacity assessment of the reinforced concrete facility in the sports and recreational compound Kraví Hora in Brno, which is up to be reconstructed. The calculation results, overall assessment and static security suggestions are interpreted in the summary of the thesis.
527

Mobilisering, statisk eller dynamisk stretch för ökad dorsalflexion i fotleden : en litteraturstudie / Mobilisation, static or dynamic stretch for increased ankle dorsiflexion : a review of current literature

Palmblad, Oscar, Daniel, Alvesköld January 2020 (has links)
Bakgrund: Fotleden används dagligen och en nedsatt fotledsrörlighet kan orsaka många problem för personer i vardagen. Knäböj är en rörelse som används både i vardagen samt i träningssammanhang och kräver en god dorsalflexion i fotleden. Det är därför värdefullt att som fysioterapeut veta vilken metod som ökar dorsalflexion inför ett rehabiliteringsprogram där knäböj ingår. Syfte: Sammanställa litteraturen gällande akuta effekter av dynamisk och statisk stretching samt posterior talocrural glide på dorsalflexion i talocruralleden hos friska individer, definierat som personer utan fysiologisk sjukdom eller trauma med eventuell påverkan på fotleden. Studien syftar även till att värdera graden av evidens för behandlingarna. Metod: Litteratursökning utfördes i databasen PubMed. Slutligen inkluderades åtta studier med sammanlagt 141 deltagare. Samtliga studier kvalitetsgranskades enligt PEDro scale, därefter användes SBU:s GRADE för evidensbedömning. Resultat: Statistisk signifikant ökning på dorsalflexion för samtliga metoder med liknande utslag på rörlighet, med liten fördel för statisk stretch. Kvalitetsgranskning enligt PEDro scale visar på att fem studier anses vara av måttlig till hög kvalitet och tre anses vara av låg kvalitet. Otillräckligt vetenskapligt underlag för posterior talocrural glide, statisk och dynamisk stretch på dorsalflexion. Konklusion: Statisk stretch, dynamisk stretch och posterior talocrural glide ökar dorsalflexionen efter minst två minuters behandling. Evidensen talar för att samtliga metoder ger liknande utfall på dorsalflexionen med en liten fördel för statisk stretch, men fler studier behövs för att bekräfta resultatet. / Background: Demands are put on the ankle daily. Limited ankle range of motion can present problems during daily activities. The squat is a movement performed both in everyday life as well as in the context of training and requires ample dorsiflexion of the ankle. Therefore, it is of value to physiotherapists to know which method should be used to increase dorsiflexion in a rehabilitation protocol where the squat is included. Objective: To provide an overview of the acute effects of static and dynamic stretching as well as posterior talocrural glide in healthy individuals without physiological diseases or trauma relating to the ankle. The study will also assess the level of evidence surrounding each of these methods. Method: The database PubMed was used to search for the included studies. A total of eight studies was included in this review, with a total of 141 participants. Study quality was judged using PEDro scale, after which SBU’s GRADE was used to determine the level of evidence for each method. Result: A statistically significant increases present for each of the methods, with similar outcomes on the dorsiflexion. Assessing the quality of the included studies with PEDro scale resulted in five studies of moderate to high quality and three of low quality. Evidence supporting posterior talocrural glide, static and dynamic stretching is deemed insufficient according to SBU’s GRADE. Conclusion: Dorsiflexion is increased after two minutes of static and dynamic stretching as well as posterior talocrural glide. The evidence suggests that similar increases are present with each method, with static stretch showing a slightly higher result. However further research is required to confirm the result.
528

Efekt proprioceptivního tréninku pro zlepšení rovnováhy analyzované počítačovou dynamickou Posturografií / Proprioception Training Effectiveness for Improving Balance analysed by Computerized Dynamic Posturography

Mukhtar, Mahera January 2020 (has links)
Effectiveness of Proprioception Training for Improving Balance Analyzed by Computerized Dynamic Posturography The Master thesis, based on conduction of an experimental study. The aim of this experimental study was to find out how one-time proprioceptive training can help in improving the balance. The method used for analyzing the balance was done on Neurocom as it is considered a validated technique for testing balance. Then proprioceptive training was performed for the static and dynamic stability effect. For instance, both side legs were trained and focused on the "short foot"/ "three point standing" by Janda, followed by static single leg standing with eyes open and then closed; secondly Dynamic standing by adding arm or leg movement while maintain the posural stability progressively. All based on the knowledge acquired during the Master Degree Physiotherapy program at FTVS UK. The participant's characteristic in the research are between the ages of 20 to 30 years, with no specific diagnose. All the 40 participants were divide into 2 groups, 20 of each. The Control group and the Experimental group (Proprioception intervention), each group has had their balance tested twice on the Neurocom (CDP). The control group was measured first and after 20 minutes they were measured again. The experimental group was...
529

Vliv ochlazení periferních částí dolních končetin na posturalní stabilitu / Influence of cooling of peripheral parts of lower extremities on postural stability

Havelková, Jana January 2019 (has links)
This thesis examines the effect of cooling of peripheral parts of lower limbs on postural stability. The introduction describes the mechanisms how cold effects the human organism and individual tissues exposed to cold, such as skin, muscles, tendons, ligaments and nerves. In addition, postural stability, etiology of balance disorders and their implications are described. The aim of the practical part of the thesis is to assess the impact of cooling of feet on postural stability and also to determine the duration of such an effect. Static stability was assessed on 26 healthy individuals with a Zebris FDT-H instrument. The cooling procedure was carried out with 10-12řC water over a period of 12 minutes. Postural stability was measured 3 times during the experiment: before the cooling, immediately after the cooling and 1 minute after the cooling. The measured variables were: the 95% COP (Centre of Pressure) confidence ellipse area, COP trajectory and COP average velocity and the distribution of weight on the soles. The impact of the cooling procedure on the 95% confidence area was statistically significant. The results of other measurements also demonstrated increased values of measured variables after the cooling procedure. The persistence of the cooling effect was evaluated by comparing the first...
530

Usage of Dynamic Analysis to Strengthen Control-Flow Analysis

Priyam Biswas (9761951) 14 December 2020 (has links)
<div>System programming languages such as C and C++ are ubiquitously used for systems software such as browsers and servers due to their flexibility and high performance. However, this flexibility comes with a price of lack of memory and type safety.</div><div><br></div><div>Control-Flow Hijacking (CFH), by taking advantage of the inherent lack of memory and type safety, has become one of the most common attack vectors against C/C++ programs. In such attacks, an attacker attempts to divert the normal control flow of the program to an attacker-controlled location. The most prominent defense against these kind of attacks is Control-Flow Integrity (CFI), which restricts the attack surface by limiting the set of possible targets for each indirect control-flow transfer. However, current analyses for the CFI target sets are highly conservative. Due to the ambiguity and imprecision in the analyses, CFI restricts adversaries to an over-approximation of the possible targets of individual indirect call sites. State-of-the-art CFI approaches fail to protect against special attack classes such as over-writing variadic function arguments. Furthermore, mitigation of control-flow attacks is not explored to its full potential in the context of language boundaries in current literature. Hence, we need effective solution to improve the precision of the CFI approaches as well as strong protection mechanisms against commonly abused corner cases.</div><div><br></div><div>We leverage the effectiveness of dynamic analysis in deriving a new approach to efficiently mitigate control-flow hijacking attacks. We present Ancile, a novel mechanism to improve the precision of the CFI mechanism by debloating any extraneous targets from the indirect control-flow transfers. We replaced the traditional static analysis approach for target discovery with seed demonstrated fuzzing. We have evaluated the effectiveness of our proposed mechanism with standard SPEC CPU benchmarks and other popular C and C++ applications.</div><div><br></div><div>To ensure complete security of C and C++ programs, we need to shield commonly exploited corners of C/C++ such as variadic functions. We performed extensive case studies to show the prevalence of such functions and their exploits. We also developed a sanitizer, HexVASAN, to effectively type-check and prevent any attack via variadic functions. CFH attacks, by abusing the difference of managed languages and their underlying system languages, are very frequent in client and server side programs. In order to safe-guard the control-flows in language boundaries, we propose a new mechanism, FitJit, to enforce type integrity. Finally, to understand the effectiveness of the dynamic analysis, we present Artemis, a comprehensive study of binary analysis on real world applications.</div>

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