The HUD is what allows players to interact with the game world and therefore the visual representation of it is of importance to usability. Usability being broken down into three components: effectiveness, efficiency and satisfaction. To study the subject a third person action game was made for the purpose. The game contained two different HUD versions to test different approaches to UI design. Results for the study were, in relation to usability, inconclusive due to a lack of participants and varying degrees of experience within the pool of participants. Preferences were gathered however, and preferences towards the stylized HUD were shown. Further study is promising as other genres could more easily adapt theories from other software fields.

During the past few years we have witnessed an emergence of Wide Area Networks in the Internet of Things area. There are several new technologies like LoRa, Wi-SUN, Sigfox, that offer long range communication and low power for low-bitrate applications. These new technologies enable new application scenarios, such as smart cities, smart agriculture, and many more. However, when these networks co-exist in the same frequency band, they may cause problems to each other since they are heterogeneous and independent. Therefore it is very likely to have frame collisions between the different networks. In this thesis we first explore how tolerant these networks are to Cross Technology Interference (CTI). CTI can be described as the interference from heterogeneous wireless technologies that share the same frequency band and is able to affect the robustness and reliability of the network. In particular, we select two of them, LoRa and Wi-SUN and carry out a series of experiments with real hardware using several configurations. In this way, we quantify the tolerance of cross technology interference of each network against the other as well as which configuration settings are important. The next thing we explored is how well channel sensing mechanisms can detect the other network technologies and how they can be improved. For exploring these aspects, we used the default Clear Channel Assessment (CCA) mechanism of Wi-SUN against LoRa interference and we evaluated how accurate it is. We also improved this mechanism in order to have higher accuracy detection against LoRa interference. Finally, we propose an architecture for WSNs which will enable flexible reconfiguration of the nodes. The idea is based on Software Defined Network (SDN) principles and could help on our case by reconfiguring a node in order to mitigate the cross-technology interference from other networks.

For the majority of the computers existence, we humans have interacted with them in a similar way, usually with a strict one-to-one relationship between user and machine. This is reflected by the design of most computers, operating systems and user applications on the market today, which are typically intended to only be operated by a single user. When computers are used for teamwork and cooperation, this design philosophy can be restricting and problematic. This paper investigates the development of shared software intended for multiple users and the impact of the single user bias in this context. A prototype software system was developed in order to evaluate different development methods for shared applications and discover potential challenges and limitations with this kind of software. It was found that the development of applications for multiple users can be severely limited by the target operating system and hardware platform. The authors conclude that new platforms are required to develop shared software more efficiently. These platforms should be tailored to provide robust support for multiple concurrent users. This work was carried out together with SAAB Air Traffic Management in Växjö, Sweden and is a bachelor's thesis in computer engineering at Linnaeus University.

Microsoft HoloLens is a headmounted augmented reality system providing users the ability to experience three-dimensional virtual content. This could be used in applications aimed at industry where users could use augmented reality to easily access information and receive instructions. For this to be suitable for industry, the system must be robust. One property of robustness was chosen for this thesis: system performance in conditions of different levels of light. A prototype implementing a use case for future industry was developed, as well as two additional smaller applications to facilitate experiments. Experiments were performed to investigate how different light levels affects the functionality in a 3D holographic application running on HoloLens and how the visibility of virtual content was affected in conditions with bright and heterogeneous backgrounds. The results showed that the functionality of the holographic application was not significantly affected except in very dark conditions, and that bright and messy backgrounds pose a problem to hologram visibility.

Lantmäteriet is developing an application that can show a three-dimensional representation of Sweden based on the data that Lantmäteriet has. The purpose of this application is to be able to crowdsource improvements and changes to the map data that Lantmäteriet has, it will also be able to be used to improve a case's information for easier and faster turnaround at Lantmäteriet. In this Project, I examine how best to use this map data to generate nature such as vegetation in this application to improve usability, and make it easier for the user to know where they are in the application. During the process, I designed a nature generator that uses polygon triangulation to better generate nature.

GraphQL is a query language for web APIs and a service for carrying out server requeststo interact with the data from the API. Research show that even for simple GraphQL queriesboth the size of the response object and the execution times to retrieve these objects may beprohibitively large and that current implementations of the language suffers from this issue.This thesis explores the implementation of an algorithm for calculating the exact size of theresponse object from a GraphQL query, and the performance based evaluation of the implementation. A proof of concept of a server using the implementation of the algorithm and subsequent tests of thecalculation times for particularly problematic queries sent to the server, show that the implementationscales well and could serve as a way to stop these queries from executing.

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Context. Apache Cassandra is an open-source, scalable, NoSQL database that distributes the data over many commodity servers. It provides no single point of failure by copying and storing the data in different locations. Cassandra uses a ring design rather than the traditional master-slave design. Virtualization is the technique using which physical resources of a machine are divided and utilized by various virtual machines. It is the fundamental technology, which allows cloud computing to provide resource sharing among the users.  Objectives. Through this research, the effects of virtualization on Cassandra are observed by comparing the virtual machine arrangement to physical machine arrangement along with the overhead caused by virtualization.  Methods. An experiment is conducted in this study to identify the aforementioned effects of virtualization on Cassandra compared to the physical machines. Cassandra runs on physical machines with Ubuntu 14.04 LTS arranged in a multi node cluster. Results are obtained by executing the mixed, read only and write only operations in the Cassandra stress tool on the data populated in this cluster. This procedure is repeated for 100% and 66% workload. The same procedure is repeated in virtual machines cluster and the results are compared.  Results. Virtualization overhead has been identified in terms of CPU utilization and the effects of virtualization on Cassandra are found out in terms of Disk utilization, throughput and latency.  Conclusions. The overhead caused due to virtualization is observed and the effect of this overhead on the performance of Cassandra has been identified. The consequence of the virtualization overhead has been related to the change in performance of Cassandra.

An increasing number of applications covered various fields generate transactional data or other time-stamped data which all belongs to time series data. Time series data mining is a popular topic in the data mining field, it introduces some challenges to improve accuracy and efficiency of algorithms for time series data. Time series data are dynamical, large-scale and high complexity, which makes it difficult to discover patterns among time series data with common methods suitable for static data. One of hierarchical-based clustering methods called BIRCH was proposed and employed for addressing the problems of large datasets. It minimizes the costs of I/O and time. A CF tree is generated during its working process and clusters are generated after four phases of the whole BIRCH procedure. A drawback of BIRCH is that it is not very scalable. This thesis is devoted to improve accuracy and efficiency of BIRCH algorithm. A sliding window BIRCH algorithm is implemented on the basis of BIRCH algorithm. At the end of thesis, the accuracy and efficiency of sliding window BIRCH are evaluated. A performance comparison among SW BIRCH, BIRCH and K-means are also presented with Silhouette Coefficient index and Calinski-Harabaz Index. The preliminary results indicate that the SW BIRCH may achieve a better performance than BIRCH in some cases.