Context. Procedural Terrain Generation refers to the algorithmical creation of terrains with limited or no user input. Terrains are an important piece of content in many video games and other forms of simulations. Objectives. In this study a tile-based approach to creating endless terrains is investigated. The aim is to find if real-time performance is possible using the proposed method and possible performance increases from utilization of the GPU. Methods. An application that allows the user to walk around on a seemingly endless terrain is created in two versions, one that exclusively utilizes the CPU and one that utilizes both CPU and GPU. An experiment is then conducted that measures performance of both versions of the application. Results. Results showed that real-time performance is indeed possible for smaller tile sizes on the CPU. They also showed that the application benefits significantly from utilizing the GPU. Conclusions. It is concluded that the tile-based approach works well and creates a functional terrain. However performance is too poor for the technique to be utilized in e.g. a video game.

A novel approach is proposed for modeling of structurally variable regions in proteins. In this approach, a prerequisite sequence-structure alignment is examined for regions where the target sequence is not covered by the structural template. These regions, extended with a number of residues from adjacent stem regions, are submitted to fold recognition. The alignments produced by fold recognition are integrated into the initial alignment to create a multiple alignment where gaps in the main structural template are covered by local structural templates. This multiple alignment is used to create a protein model by existing protein modeling techniques. Several alternative parameters are evaluated using a set of ten proteins. One set of parameters is selected and evaluated using another set of 31 proteins. The most promising result is for loop regions not located at the C- or N-terminal of a protein, where the method produces an average RMSD 12% lower than the loop modeling provided with the program MODELLER. This improvement is shown to be statistically significant.

The aim of this work is to investigate whether threaded Android-applications written in C or C++ are more time-efficient than threaded Android-applications written in Java. The first part of the work was to perform a literature analysis in order to find out which types of algorithms were used in previous studies comparing the performance between non-threaded Android-applications written in Java and C/C++. Another literature analysis was performed where the outcome was to find suitable threaded versions of algorithms that could be used to compare the difference in time-consumption between algorithms implemented in Java and C/C++. Results have shown that for simple arithmetic operations and sorting functions, it is still possible to gain performance in terms of time-efficiency by implementing applications in C/C++. However, there are clear indications that these gains are smaller than they are in the non-threaded case. In algorithms dealing with string operations, the Java-version was significantly more time-efficient than the C++-version

This thesis is an analysis of frameworks which support multithreading application devel-opment on platform Java. In particular this thesis analyses the overview of libraries which supports multithreading development in this language. Provided features are shown and described by the code examples. The thesis describes the principles of concurrent pro-gramming. Although multithreaded applications undoubtedly have many advantages, one of the goals of the thesis is to highlight the possible risks associated with their use. By the analysis of Java platform, I used method of description, analysis, synthesis and comparison. This thesis is composed of theoretical part, which defines the basic concepts and principles of concurrent applications. Theoretical parts also contain recherché of works, which deal with the topic of concurrent programming. In the analytical part are described and evaluated changes at various versions of Java language. Benefit of this work is clear documentation and evaluation of Java language concurrent utilities, from the oldest version of Java 1 to latest Java 8. So this work can help those, who need to learn how to develop concurrent applications in Java.

Context - Software applications on the web are more commonly used nowadays than before. As a result of this, the performance needed to run the applications is increasing. One method to increase performance is writing multi-threaded code using Web Workers in JavaScript. Objectives - We will investigate how using Web Workers can increase responsiveness, raw computational power and decrease load time. Additionally, we will conduct a survey that targets software developers to find out their opinions about performance in web applications, multi-threading and more specifically Web Workers. Realization (Method) - We created three experiments that concentrate on the areas mentioned above. The experiments are hosted on a web server inside an isolated Docker container to eliminate external factors as much as possible. To complement the experiments we sent out a survey to collect information of developers' opinions about Web Workers. The criteria for the selection of developers were some JavaScript experience. The survey contained questions about their opinions on switching to a multi-threaded workflow on the web. Do they experience performance issues in today's web applications? Could Web Workers be useful in their projects? Results - Responsiveness shifted from freezing the website to perfect responsiveness when using Web Workers. Raw computational power increased at best 67% when using eight workers with tasks that took between 100 milliseconds and 15 seconds. Over 15 seconds, sixteen workers improved the computational power further with around 3% - 9% compared to eight workers. At best the completion time decreased with 74% in Firefox and 72% in Chrome. Using Web Workers to help with load time gave a big improvement but is somewhat restricted to specific use cases. Conclusions - Using Web Workers to increase responsiveness made an immense difference when moving tasks that is affecting the users responsiveness to background threads. Completion time for big computational tasks was quicker in use cases where you can split the workload to separate portions and use multiple threads in parallel to complete the tasks. Load time can be improved with Web Workers by completing some tasks after the page is done loading, instead of waiting for all tasks to complete and then load the page. The survey indicated that many have performance in mind and would consider writing code in a multi-threaded way. The knowledge about multi-threading and Web Workers was low. Although, most of the participants believe that Web Workers would be useful in their current and future projects, and are worth the effort to implement.

This Master thesis aims to increase the effectivity of the machining of pneumatic cylinders specific components. In the first chapter, the concurrent approach to the manufacture of corrosion resistant austenitic piston rod. This approach consists of the technological procedure, the analysis of the cutting tools used in the process and the cutting conditions. The machining process deals with low durability of cutting tools and the necessity of continual supervision by the operator. Therefore, an alternate design of cutting tools and cutting conditions is suggested in the next chapter. The new design has been tested in manufacture process. In the last chapter, the concurrent and the innovative approach are compared. By choosing the proper cutting tools and cutting conditions it was managed to increase the durability of cutting tools and to increase the effectivity of the whole manufacture process.

No description available.

Similarity searches are an essential component to most bioinformatic applications. They form the bases of structural motif identification, gene identification, and insights into functional associations. With the rapid increase in the available genetic data through a wide variety of databases, similarity searches are an essential tool for accessing these data in an informative and productive way. In our chapter, we provide an overview of similarity searching approaches, related databases, and parameter options to achieve the best results for a variety of applications. We then provide a worked example and some notes for consideration. Homology detection is one of the most basic and fundamental problems at the heart of bioinformatics. It is central to problems currently under intense investigation in protein structure prediction, phylogenetic analyses, and computational drug development. Currently discriminative methods for homology detection, which are not readily interpretable, are substantially more powerful than their more interpretable counterparts, particularly when sequence identity is very low. Here I present a computational graph-based framework for homology inference using physiochemical amino acid properties which aims to both reduce the gap in accuracy between discriminative and generative methods and provide a framework for easily identifying the physiochemical basis for the structural similarity between proteins. The accuracy of my method slightly improves on the accuracy of PSI-BLAST, the most popular generative approach, and underscores the potential of this methodology given a more robust statistical foundation.

In the automotive industry, Al-Si alloy is widely used for manufacturing of various engine parts. Machinability of die-cast Al-12Si alloy is challenging due to severe abrasion and adhesion wear of the tools. Form tapping is a common method for generating internal threads in engine blocks. It is usually a finishing process on a production line. An unexpected tap failure may lead to significant scrap and high rework costs. The objective of this research was to investigate the wear mechanisms of high-speed steel form taps when machining Al-12Si alloy. This research involved replicating the same process conditions as the industry partner to determine a feasible solution without changing the tap geometry or process parameters. A critical region of wear on the crest was identified where the aluminum adhesion was acute. Intense abrasion wear occurred on the crest and flanks due to hard silicon precipitates. In this study, two methods were proposed for measuring linear and volumetric wear on the chamfered threads. The second and third chamfered threads experienced the most significant wear on the tap. To improve wear-resistance of the form tap, PVD surface coatings were deposited on it. The preliminary tests of 12 surface coatings showed coating-delamination mostly on the critical region. A progressive wear study of the TiAlN coating showed an improvement in tap performance over the ZrN coating currently used. By the 4320th hole, the volumetric wear of the TiAlN coated tap was reduced by nearly 200% and 50% when compared against the uncoated and ZrN coated taps, respectively. / Thesis / Master of Applied Science (MASc)

Due to the ever increasing complexity of safety-critical applications, handwritten code is being replaced by automatically generated code derived from a high level specification. Code generation from high level specification requires a model of computation with an underlying formalism and correctness-preserving refinement steps to generate the lower level application code. Such software synthesis techniques are said to be 'correct-by-construction'. Synchronous programming languages such as Esterel, LUSTRE, which are based on a synchronous model of computation are used for sequential code generation. They work on a synchrony assumption (zero time intraprocess computation and zero time inter process communication) at the specification level. Early versions of synchronous languages followed an execution pattern where an iteration of software was mapped to an interval between ticks of an external reference clock. Since this external reference tick was unrelated to variables (or signals) within the software, redundant operations such as reading of ports, computation of guards were performed for each tick. In this dissertation, we highlight some of these performance issues and missed optimization opportunities. Also we show how a multi-clock (or polychronous) formalism, where each variable has an independent rate of execution associated with it, can avoid these problems. An existing polychronous language named SIGNAL, creates a hierarchy of clocks based on the rate of execution of individual variables, to form a root clock which acts a reference tick. We seek to replace the clock analysis with a technique to form a unique order of events without a reference time line. For this purpose, we present a new polychronous formalism termed Multi-rate Instantaneous Channel connected Data Flow (MRICDF). Our new synthesis technique inspects the specification to identify a master trigger at a Boolean equation level to act as the reference tick. Furthermore, we attempt to make polychronous specification based software synthesis more accessible to practicing engineers, by constructing a software tool EmCodeSyn, with a visual environment for specification and a more intuitive analysis technique. Our Boolean approach to sequential synthesis of embedded software has multiple implementations, each of which utilizes existing academic software tools. Optimizations are proposed to minimize synthesis time by simplifying the input to these external tools. Weaknesses in causal loop analysis techniques applied by existing synthesis tools are highlighted and solutions for performing time efficient loop analysis are integrated into EmCodeSyn. We have also determined that a part of the non-synthesizable polychronous specifications can be used to generate correct multi-threaded code. Additionally, we investigate composition of polychronous modules and propose properties that are necessary to guarantee agreement on shared signals. / Ph. D.