Uniview är mjukvara som främst används som presentations- och visualiseringsverktyg vid pla- netarium. För att utforska nya användningsområden av Uniview vill man på Sciss integrera sin mjukvara med headsets för virtuell verklighet. Den här studien redogör för de metoder och verk- tyg som användes i utvecklingen av en prototyp, vars syfte är att visa om detta är en eftersträvans- värd tillämpning av planetariemjukvaran.Prototypen byggdes i spelmotorn Unity och är ett exempel på flitigt återanvändande av kod och mjukvara, till exempel användes ramverket Spout för att överföra bildinformation från Uniview. För att göra prototypen utfördes en snabb kravspecifikation bestående av målgruppsidentifiering, val av funktioner och formgivning. En genomförbarhetsstudie gjordes för att bestämma vilka tek- nologier som skulle användas i implementationen. Prototypen implementerades sedan enligt ob- jektorienterade designprinciper och mönster.Användningstestning av den producerade prototypen indikerade att virtuell verklighet hade pot- ential som användningsområde för Uniview. / Uniview is a software primarily used as a presentation and visualisation tool at planetariums. To explore new ways to make use of Uniview, Sciss wants to integrate their software with head mounted displays for virtual reality. This study describes the methods and tools used to develop a prototype with the purpose of exploring if this is a worthwhile application of the planetarium software.The prototype was built in the game engine Unity and is an example of industrious reuse of code and software, for example the framework Spout was used to transfer images from Uniview. The prototype went through a short process of requirements specification with identification of target audience, choice of functionality and layout design. A feasibility study was done in order to find out what technologies should be used in the implementation. The prototype was then implemen- ted according to object-oriented design principles and patterns.User testing of the produced prototype indicated that virtual reality had potential as an applicat- ion scope for Uniview.

This thesis studies the control algorithms used by a team of ECAVs (Electronic Combat Air Vehicle) to deceive a network of radars to detect a phantom track. Each ECAV has the electronic capability of intercepting the radar waves, and introducing an appropriate time delay before transmitting it back, and deceiving the radar into seeing a spurious target beyond its actual position. On the other hand, to avoid the errors and increase the reliability, have a complete coverage in various atmosphere conditions, and confronting the effort of the belligerent intruders to delude the sentinel and enter the area usually a network of radars are deployed to guard the region. However, a team of cooperating ECAVs could exploit this arrangement and plans their trajectories in a way all the radars in the network vouch for seeing a single and coherent spurious track of a phantom. Since each station in the network confirms the other, the phantom track is considered valid. This problem serves as a motivating example in trajectory planning for the multi-agent system in highly constrained operation conditions. The given control command to each agent should be a viable one in the agent limited capabilities, and also drives it in a cumulative action to keep the formation. In this thesis, three different approaches to devise a trajectory for each agent is studied, and the difficulties for deploying each one are addressed. In the first one, a command center has all information about the state of the agents, and in every step decides about the control each agent should apply. This method is very effective and robust, but needs a reliable communication. In the second method, each agent decides on its own control, and the members of the group just communicate and agree on the range of control they like to apply on the phantom. Although in this method much less data needs to communicate between the agents, it is very sensitive to the disturbances and miscalculations, and could be easily fell apart or come to a state with no feasible solution to continue. In the third method a differential geometric approach to the problem is studied. This method has a very strong backbone, and minimizes the communication needed to a binary one. However, less data provided to the agents about the system, more sensitive and infirm the system is when it faced with imperfectionalities. In this thesis, an object oriented program is developed in the Matlab software area to simulate all these three control strategies in a scalable fashion. Object oriented programming is a naturally suitable method to simulate a multi-agent system. It gives the flexibility to make the code more iv close to a real scenario with defining each agent as a separated and independent identity. The main objective is to understand the nature of the constrained dynamic problems, and examine various solutions in different situations. Using the flexibility of this code, we could simulate several scenarios, and incorporate various conditions on the system. Also, we could have a close look at each agent to observe its behavior in these situations. In this way we will gain a good insight of the system which could be used in designing of the agents for specific missions.

This thesis describes initial language extensions to the Modelica language to define a more general language called PDEModelica, with built-in support for modeling with partial differential equations (PDEs). Modelica® is a standardized modeling language for objectoriented, equation-based modeling. It also supports component-based modeling where existing components with modified parameters can be combined into new models. The aim of the language presented in this thesis is to maintain the advantages of Modelica and also add partial differential equation support. Partial differential equations can be defined using a coefficient-based approach, where a predefined PDE is modified by changing its coefficient values. Language operators to directly express PDEs in the language are also discussed. Furthermore, domain geometry description is handled and language extensions to describe geometries are presented. Boundary conditions, required for a complete PDE problem definition, are also handled. A prototype implementation is described as well. The prototype includes a translator written in the relational meta-language, RML, and interfaces to external software such as mesh generators and PDE solvers, which are needed to solve PDE problems. Finally, a few examples modeled with PDEModelica and solved using the prototype are presented. / <p>Report code: LiU-Tek-Lic-2002:63.</p>

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<p> </p> <p>Productive programmable accelerators, like GPUs, have been developed for generations to support programming features. The ever-increasing performance improves the usability of programming features on GPUs, and these programming features further ease the porting of code and data structure from CPU to GPU. However, GPU programming features, such as function call or runtime polymorphism, have not been well explored or optimized.</p> <p>I identify efficient and productive GPU programming as a potential area to exploit. Although many programming paradigms are well studied and efficiently supported on CPU architectures, their performance on novel accelerators, like GPUs, has never been studied, evaluated, and made perfect. For instance, programming with functions is a commonplace programming paradigm that shapes software programs with modularity and simplifies code with reusability. A large amount of work has been proposed to alleviate function calling overhead on CPUs, however, less paper talked about its deficiencies on GPUs. On the other hand, polymorphism amplifies an object’s behaviors at runtime. A body of work targets</p> <p>efficient polymorphism on CPUs, but no work has ever discussed this feature under GPU contexts.</p> <p><br></p> <p>In this dissertation, I discussed those two programming features on GPU architectures. First, I performed the first study to identify the deficiency of GPU polymorphism. I created micro-benchmarks to evaluate virtual function overhead in controlled settings and the first GPU polymorphic benchmark suite, ParaPoly, to investigate real-world scenarios. The micro-benchmarks indicated that the virtual function overhead is usually negligible but can</p> <p>cause up to a 7x slowdown. Virtual functions in ParaPoly show a geometric meaning of 77% overhead on GPUs compared to the function’s inlined version. Second, I proposed two novel techniques that determine an object’s type only by its address pointer to improve GPU polymorphism. The first technique, Coordinated Object</p> <p>Allocation and function Lookup (COAL) is a software-only technique that uses the object’s address to determine its type. The second technique, TypePointer, needs hardware modification to embed the object’s type information into its address pointer. COAL achieves 80%  and 6% improvements, and TypePointer achieves 90% and 12% over contemporary CUDA and our type-based SharedOA.</p> <p>Considering the growth of GPU programs, function calls become a pervasive paradigm to be consistently used on GPUs. I also identified the overhead of excessive register spilling with function calls on GPU. To diminish this cost, I proposed a novel Massively Multithreaded Register Windowing technique with Variable Size Register Window and Register-Conscious Warp Scheduling. Our techniques improve the representative workloads with a geometric</p> <p>mean of 1.18x with only 1.8% hardware storage overhead.</p>

The complexity of chip design has been exponentially rising, resulting in increased complexity and costs in chip verification. This rise in complexity results in increased time to market and increases risks of chip in fabrication, that can be catastrophic and result in major losses. For this reason, it is necessary for companies to ensure the verification testbenches used are predictable and reusable. The SystemVerilog language is a Hardware Verification Language that adopts the object-oriented principles. It is a highly suitable language for verification environments as it offers functional coverage, constrained random testing and assertions. The Universal Verification Methodology package consists of SystemVerilog libraries used for the industry grade verification environments. The Universal Verification Methodology takes advantages of features and design patterns from software engineering in general and Object-oriented Programming in particular, such as data hiding to raise the level of abstraction, generic programming to increase reusability, polymorphism for inter-operability, etc. There is a lot of pressure on the performance of today’s verification teams. This thesis develops a functional verification environment for the Avalon Streaming Interface while incorporating design practices that make the environment far more robust and reusable. The study focuses on instilling properties in the Verification environment that help save verification time. / Komplexiteten i chipdesign har ökat exponentiellt, vilket resulterat i ökad komplexitet och ökade kostnader vid chipverifiering. Denna ökning i komplexitet resulterar i längre tid till marknaden och ökar riskerna vid tillverkning av kiselchip, vilket kan vara katastrofalt och leda till stora förluster. Av denna anledning är det nödvändigt för företag att säkerställa att de testbänkar som används vid verifiering är förutsägbara och återanvändbara. Språket SystemVerilog är ett verifieringsspråk för maskinvara med objektorienterade egenskaper. Det är mycket lämpligt i verifieringsmiljöer eftersom det erbjuder funktionell täckning, målmässigt begränsade slumpmässiga tester samt påstenden i form av assertions. Biblioteket Universal Verification Methodology består av SystemVerilog-funktioner som används vid verifiering i industrimiljöer. Den universella verifieringsmetoden drar fördel av funktioner och designmönster från mjukvaruteknik i allmänhet och Objektorienterad Programmering i synnerhet, genom att gömma data för att höja abstraktionsnivån, generisk programmering för att öka återanvändbarheten, polymorfism för interoperabilitet, etc. Det är mycket press på prestandan för dagens verifieringslag. Denna avhandling utvecklar en funktionell verifieringsmiljö för ett Avalon Streaming Interface samtidigt som det integrerar designpraxis vilket gör miljön mycket mer robust och återanvändbar. Studien fokuserar på att inkludera egenskaper i verifieringsmiljön vilka hjälper till att spara verifieringstid.

A Windows based post processor for the design of reinforced concrete space frames is developed. The post processor is capable of designing beams and columns of reinforced concrete space frames in accordance with the ACI specification. The program is developed in C++ using the object oriented programming approach. The objects used in the program represents a one to one analogy with objects in the real world. The computer model of a structure is composed of objects like members, joints, loads, beams and columns. The development of the post processor is discussed and the program architecture is presented. The design results obtained from the post processor are compared with those obtained from several commercial structural design programs to ensure the correctness of the design. It was concluded that the application of object oriented programming techniques results in programs that are easier to develop and maintain and also greatly reduces the effort required for developing applications for graphical user interfaces. / Master of Science

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The way in which application systems and software are built has changed dramatically over the past few years. This is mainly due to advances in hardware technology, programming languages, as well as the requirement to build better software application systems in less time. The importance of mondial (worldwide) communication between systems is also growing exponentially. People are using network-based applications daily, communicating not only locally, but also globally. The Internet, the global network, therefore plays a significant role in the development of new software. Distributed object computing is one of the computing paradigms that promise to solve the need to develop clienVserver application systems, communicating over heterogeneous environments. This study, of limited scope, concentrates on one crucial element without which distributed object computing cannot be implemented. This element is the communication software, also called middleware, which allows objects situated on different hardware platforms to communicate over a network. Two of the most important middleware standards for distributed object computing today are the Common Object Request Broker Architecture (CORBA) from the Object Management Group, and the Distributed Component Object Model (DCOM) from Microsoft Corporation. Each of these standards is implemented in commercially available products, allowing distributed objects to communicate over heterogeneous networks. In studying each of the middleware standards, a formal way of comparing CORBA and DCOM is presented, namely meta-modelling. For each of these two distributed object infrastructures (middleware), meta-models are constructed. Based on this uniform and unbiased approach, a comparison of the two distributed object infrastructures is then performed. The results are given as a set of tables in which the differences and similarities of each distributed object infrastructure are exhibited. By adopting this approach, errors caused by misunderstanding or misinterpretation are minimised. Consequently, an accurate and unbiased comparison between CORBA and DCOM is made possible, which constitutes the main aim of this dissertation. / Computing / M. Sc. (Computer Science)