We often want a compiler to generate executable code that runs as fast as possible. One consideration toward this goal is to keep values in fast registers to limit the number of slower memory accesses that occur. When there are not enough physical registers available for use, values are ``spilled'' to the runtime stack. The need for spills is discovered during register allocation wherein values in use are mapped to physical registers. One factor in the efficacy of register allocation is the number of values in use at one time (register collisions). Register collision is affected by compiler optimizations that take place before register allocation. Though the main purpose of compiler optimizations is to make the overall code better and faster, some optimizations can actually increase register collisions. This may force the register allocation process to spill. This thesis studies the effects of different compiler optimizations on register collisions.

Creating websites today is not easy as it seems, therefore it is important to know the essential principle when developing new product for users. Knowing the essential principles is not enough, you will also need to know about what users think and feel is important on a website such as Stack Overflow. It is a question-and-answer website where it offers users the ability to post questions and receive answers from other users that uses the same website. This study will identify what is important for young adult developers on the website Stack Overflow and what they think, and feel is required in terms of usability on the website. In this study there will be a theoretical framework and it includes different aspects of usability: learnability, comprehensibility, navigation, flexibility, and discoverability. This theoretical framework has been created to be able to identify what is important for young adult developers on the website Stack Overflow. By using this theoretical framework, we can setup the data collection method which is interview and think-aloud-test. As for analysis of the data, content analysis has been used to analyze the results and the study reached its conclusion. The conclusion is that on a website like Stack Overflow, navigation, flexibility, and comprehensibility are the important aspects for young adult developers.

When starting a new software project, selecting what technology stack to use is one of the most important decisions to make. Selecting a technology stack is a large part of the software architecture design, and the choice of the technology stack is crucial to get right since it can make or break a project and is usually hard and expensive to change in the future. This thesis was conducted to develop guidelines for organisations to use during the technology stack selection process by identifying the essential steps of the technology stack selection process at private sector organisations with multiple development teams that perform in-house development. As well as identifying scenarios where it is reasonable to choose similar technology stacks for different development teams, and scenarios where it is reasonable to select different technology stacks for different development teams. The guidelines aim to help organisations evaluate different solutions and help organisations decide whether it is worth it to choose different technology stacks for different development teams. The guidelines provide the essential steps of technology stack selection, control questions that can be used to evaluate whether a given technology stack would work for an organisation, as well as scenarios where it is reasonable to select similar or different technology stacks for multiple development teams. The guidelines are developed using Design Science Research and semi-structured interviews with software developers, software architects and managers at Husqvarna and other organisations that agreed to participate. The interviews were analysed using thematic content analysis to develop a draft of the guidelines, which was then attached to a survey that was sent out to gather feedback which helped further improve the guidelines and validate that they apply to a broad audience. This thesis does not cover technological aspects of technology stack selection, such as performance or efficiency, nor does it cover programs or tools used to aid the development, like integrated development environments (IDE:s), code-sharing software or team communication tools.

The continued scaling of device dimensions in complementary metal oxide semiconductor (CMOS) technology within the sub-100 nm region requires an alternative high dielectric constant (high-k) oxide layer to counter high tunneling leakage currents, a metallic gate electrode to address polysilicon depletion, boron penetration and high polysilicon sheet resistance, and high mobility channel materials to boost the CMOS performance. Metal gates can also offer improved thermal and chemical stability, but their use requires that we improve our understanding of how the metal alloy phase, crystallographic orientation, and composition affect the electronic properties of the metal alloy-oxide interface. To replace n++ and p++ polysilicon gate electrodes and maintain scaled device performance requires metal gate electrodes with work functions within 0.2 eV of the silicon conduction and valence band edges, i.e., 5.0-5.2 and 4.1-4.3 eV, for PMOS and NMOS devices, respectively. In addition to work function and thermal/chemical stability, metal gates must be integrated into the CMOS process flow. It is the aim of this work to significantly expand our knowledge base in alloys for dual metal gates by carrying out detailed electrical and materials studies of the binary alloy systems of Ru with p-type metal Pt. Three n-type metals systems, Ru-Ta, Ru-Hf and Ru-Nb have also been partially investigated. This work also focuses on high mobility Ge p-MOSFETs for improved CMOS performance. DC magnetron sputtering has been used to deposit binary alloy films on thermally grown SiO2. The composition of the alloy films have been determined by Rutherford backscattering spectrometry and the identification of phases present have been made using x-ray and electron diffraction of samples. The microstructure of the phases of interest has been examined in the transmission electron microscope and film texture was characterized via x-ray diffraction. The electrical characterization includes basic resistivity measurements, and work function extraction. The work function has been determined from MOS capacitor and Schottky diodes. The need for electron and hole mobility enhancement and the progress in the development of high-k gate stacks, has lead to renewed interest in Ge MOSFETs. The p-MOS mobility data for Ge channel devices have been reported. The results indicate greater than 2 x improvements in device mobility as compared to standard Si device. A low frequency noise assessment of silicon passivated Ge p-MOSFETs with a TiN/TaN/HfO2 gate stack has been made. For the first time we also report results on low frequency noise characterisation for a Ge P+- n junctions with and without Ni germanidation.

This thesis investigates the in-plane shear performance of full-scale walls made from compressed earth blocks. Compressed earth blocks are a type of masonry where the blocks are composed of compressed soil and typically dry-stacked without mortar. Prior research has demonstrated that the in-plane shear strength of these blocks falls far short of capacities predicted by conventional masonry building codes, requiring new testing to develop effective and safe designs for seismic conditions. This thesis specifically studies the effects of block type and the use of grouted shear keys at the block head joints. Three full-scale walls were constructed and tested under in-plane, cyclic loading. To compare the effect of block type on shear strength, one wall was constructed from Rhino blocks as used by the Center for Vocational Building Technology, while another used V-Lock blocks designed by the Vermeer Corporation. Apart from differences in size and interlock mechanism, the standard Rhino blocks have shear keys at the head joints which are not present on the V-Lock blocks. To examine the effect of these shear keys, a third wall was built from Rhino blocks with the shear keys removed. The two standard block types displayed no major difference in strength that could not be attributed to grouted area or the presence/absence of the head joint shear keys. The Rhino block wall with shear keys reached a higher peak load relative to the grouted area but experienced a brittle drop in capacity after peaking, while the other two walls exhibited an extended loading plateau after the initial peak. All walls failed with cracking and block sliding along the main diagonals, a failure mode similar to conventional masonry. Proposals are made for modifying the equations for shear capacity from the Masonry Standards Joint Committee (MSJC) 2013 code for use in designing compressed earth block shear walls.

Control-flow hijack attacks on software exploit vulnerabilities in the software’s memory handling. Over the years, various security mitigations have been developed to counter these attacks. However, compatibility issues have hindered the adoption of such measures in some legacy systems. This thesis focuses on the case of the legacy DOS system and examines whether a DOS system running the DOS/4GW protected mode extender can provide control-flow protection against an attack exploiting a buffer overflow vulnerability in the well-known retro game Duke Nukem3D. To investigate this, three model programs were created, and designed with memory models that share memory layout characteristics with the target retro game’s executable. Experimental attacks were then conducted on these models, aiming to identify an effective attack vector for the target vulnerability. The underlying theory suggests that memory models that segregate application data into distinct memory segments could potentially safeguard against the demonstrated attack. However, attempts to implement such a memory model within an application proved unsuccessful. The challenge that remains is to prove the existence of memory models under DOSprotected mode that can effectively shield Duke Nukem 3D, or other legacy games, from the control-flow hijack attack demonstrated in this thesis.

In manufacturing, requirements are an essential aspect of the development process. A requirements view provides a perspective on how requirements are incorporated into the design and architecture of a system. Requirements documents for different product versions at a company like Alstom contain operational scenarios and Given-When-Then requirements, a specific format for expressing functional requirements. Operational scenarios are examples of how the product will be used in real-world situations, and they can also be useful for identifying and specifying functional and nonfunctional requirements. Currently, operational scenarios are manually linked to Given-When-Then requirements. This thesis presents a conceptual design that streamlines the requirements engineering process and allows for easier linking operational scenarios to Given-When-Then requirements.

No description available.

This thesis develops and presents a new remanufacturing MRP time-phased scheduling algorithm utilizing a critical path concept, as in the project management field, for incorporation into remanufacturing production planning MRP calculations. The algorithm automates the remanufacturing lead time allowance calculation for child subassemblies and component parts in the form of Stack Time, and as such creates a linkage between the parent remanufacturing routing operation to which a remanufactured subassembly or component part is allocated for further processing, and the parent routing operation from which it is disassembled. This new MRP scheduling algorithm is optimal for calculating the total planned production time of remanufacturing production routings, and is appropriate for even large, complex, multilevel BOM structures.

No description available.