<p dir="ltr">The presence of digital devices in various settings, from workplaces to personal spaces, necessitates reliable and secure data storage solutions. These devices store data on non-volatile media like Solid State Drives (SSDs) and Hard Disk Drives (HDDs), ensuring data preservation even after power loss. Files, fundamental units of data storage, are created, modified, and deleted through user activities like application installations or file management. File systems, acting as the backbone of the system, manage these files on storage devices.</p><p dir="ltr">This research explores how three key factors: (1) different operating systems running various file system types (ext4, NTFS, FAT, etc.), (2) different disk types (SSD and HDD), and (3) common user activities (system shutdowns, reboots, web browsing, downloads, etc.) influence the persistence of deleted files.</p><p dir="ltr">This research aims to fill a gap in the understanding by looking at how these factors influence how quickly new information overwrites deleted files. This is especially important for digital forensics, where investigators need to be sure they can find all the evidence on a device. The research will focus on how operating systems handle deleted files and how everyday activities affect the chances of getting them back. This can ultimately improve data security and make digital forensics more reliable.</p>

The price of the tools for making prototypes and small series of products, as well as the cost of additional changes in the tool are quite high and increase the price of the final product. A flexible tool provides an advantageous solution to create a wide variety of molds. In this thesis the area of flexible tooling is introduced. An experimental mechanism has been manufactured and tested. With the help of a methodical approach several solutions for a flexible tool design have been proposed. Based on the evaluation of all given criteria, the most suited version has been designed and manufactured. The tool has been tested and evaluated for the thermoforming process. Improvements and potential applications have been suggested. The results show that the flexible tool has some limitations but has a broad potential use in several applications.

A key factor in creating software of good quality is that the requirements for the project being developed are as unambiguous and clear as possible, so the developers will be able to develop the product quickly and effectively. So, there is a need for tools that help requirements engineers create quality requirements. The attributes that define a poorly written requirement are called bad smells. In this thesis we investigate the NALABS tools bad smell detecting capabilities when analyzing industrial requirements. First, we performed a literature study to investigate what types of bad smells exist for requirements and how they were specified. After that we used a case study to examine how many smells and of what categories the NALABS tool detects, when it analyzes industrial requirements. Lastly, we used a small experiment to examine how accurately NALABS detects smells, by designing a simple console application that counted instances of bad smell words in a set of keywords that were from the NALABS tool. The results we gathered gave us an indication that NALABS detects bad smells in all the categories of bad smells that are implemented in it, to a varying degree. Through this thesis we hope to extend the knowledge about bad requirements smells, clarify what attributes of a requirement might be a bad smell, and investigate to what degree the NALABS tool can detect bad smells in industrial requirements.

Finding a way to automate the generation of test data is a crucial aspect of software testing. Testing comprises 50% of all software development costs [Korel90]. Finding a way to automate testing would greatly reduce cost and labor involved in the task of software testing. One of the ways to automate software testing is to automate the generation of test data inputs. For example, in statement coverage, creating test cases that will cover all of the conditions required when testing that program would be costly and time-consuming if undertaken manually. Therefore, a way must be found that allows the automation of creating test data inputs to satisfy all test requirements for a given test. One such way of automating test data generation is the use of genetic algorithms. Genetic algorithms use the creation of generations of test inputs, and then choose the most fit test inputs, or those test inputs that are most likely to satisfy the test requirement, as the test inputs that will be passed to the next generation of inputs. In this way, the solution to the test requirement problem can be found in an evolutionary fashion. Current research suggests that comparison of genetic algorithms with random test input generation produces varied results. While results of these studies show promise for the future use of genetic algorithms as an answer to the issue of discovering test inputs that will satisfy branch coverage, what is needed is additional experimental research that will validate the performance of genetic algorithms in a test environment. This thesis makes use of the EvoSuite plugin tool, which is a software plugin for the IntelliJ IDEA Integrated Development Environment that runs using a genetic algorithm as its main component. The EvoSuite tool is run against 22 Java classes, and the EvoSuite tool will automatically generate unit tests and will also execute those unit tests while simultaneously measuring branch coverage of the unit tests against the Java classes under test. The results of this thesis’ experimental research are that, just as the literature indicates, the EvoSuite tool performed with varied results. In particular, Fraser’s study of the EvoSuite tool as an Eclipse plugin was accurate in depicting how the EvoSuite tool would come to perform as an IntelliJ plugin, namely that the EvoSuite tool would perform poorly for a large number of classes tested.

The thesis is focused on testing of the cutting tools for machining on five axis machine tools and possibility of implementation of designed experiments in this area. The theoretical section focuses attention on analysis of specific features during five axis machining, including chip cross section and particularity of tool testing under high speed cutting conditions with consideration of dynamic stability of cutting tools. In the thesis force loading of the tool is discussed as well as its measurement process, considering force development caused by tool wear and data analysis. Description of designed experiment and its application to the area of tool testing is included as well. All theoretical predictions are followed by experimental verifying by extensive number of experimental tests, including evaluation of cutting tool condition, influence of hard coatings on cutting power of the tools, etc. For each of testing conditions are designed specific methods of processing of gathered data as well as evaluation of power of the cutting tools. Gathered data were processed by means of statistical evaluation and by statistical methods of designed experiments. The thesis contains also the extensive number of records and analysis, documented by means of light microscopy as well as electron microscopy.

The thesis is focused on testing of the cutting tools for machining on five axis machine tools and possibility of implementation of designed experiments in this area. The theoretical section focuses attention on analysis of specific features during five axis machining, including chip cross section and particularity of tool testing under high speed cutting conditions with consideration of dynamic stability of cutting tools. In the thesis force loading of the tool is discussed as well as its measurement process, considering force development caused by tool wear and data analysis. Description of designed experiment and its application to the area of tool testing is included as well. All theoretical predictions are followed by experimental verifying by extensive number of experimental tests, including evaluation of cutting tool condition, influence of hard coatings on cutting power of the tools, etc. For each of testing conditions are designed specific methods of processing of gathered data as well as evaluation of power of the cutting tools. Gathered data were processed by means of statistical evaluation and by statistical methods of designed experiments. The thesis contains also the extensive number of records and analysis, documented by means of light microscopy as well as electron microscopy.