Dissertations / Theses on the topic 'SINK (Computer system)'

In this investigation, a single phase fluid is used to study the coupling between natural convection heat transfer within an enclosure and forced convection through computer covering case to cool the electronic chip. Two working fluids are used (water and air) within a rectangular enclosure and the air flow through the computer case is created by an exhaust fan installed at the back of the computer case. The optimum enclosure size configuration that keeps a maximum temperature of the heat source at a safe temperature level (85℃) is determined. The cooling system is tested for varying values of applied power in the range of 15−40𝑊. The study is based on both numerical models and experimental observations. The numerical work was developed using the commercial software (ANSYS-Icepak) to simulate the flow and temperature fields for the desktop computer and the cooling system. The numerical simulation has the same physical geometry as those used in the experimental investigations. The experimental work was aimed to gather the details for temperature field and use them in the validation of the numerical prediction. The results showed that, the cavity size variations influence both the heat transfer process and the maximum temperature. Furthermore, the experimental results ii compared favourably with those obtained numerically, where the maximum deviation in terms of the maximum system temperature, is within 3.5%. Moreover, it is seen that using water as the working fluid within the enclosure is capable of keeping the maximum temperature under 77℃ for a heat source of 40𝑊, which is below the recommended electronic chips temperature of not exceeding 85℃. As a result, the noise and vibration level is reduced. In addition, the proposed cooling system saved about 65% of the CPU fan power.

In this investigation, a single phase fluid is used to study the coupling between natural convection heat transfer within an enclosure and forced convection through computer covering case to cool the electronic chip. Two working fluids are used (water and air) within a rectangular enclosure and the air flow through the computer case is created by an exhaust fan installed at the back of the computer case. The optimum enclosure size configuration that keeps a maximum temperature of the heat source at a safe temperature level (85°C) is determined. The cooling system is tested for varying values of applied power in the range of 15-40W. The study is based on both numerical models and experimental observations. The numerical work was developed using the commercial software (ANSYS-Icepak) to simulate the flow and temperature fields for the desktop computer and the cooling system. The numerical simulation has the same physical geometry as those used in the experimental investigations. The experimental work was aimed to gather the details for temperature field and use them in the validation of the numerical prediction. The results showed that, the cavity size variations influence both the heat transfer process and the maximum temperature. Furthermore, the experimental results ii compared favourably with those obtained numerically, where the maximum deviation in terms of the maximum system temperature, is within 3.5%. Moreover, it is seen that using water as the working fluid within the enclosure is capable of keeping the maximum temperature under 77°C for a heat source of 40W, which is below the recommended electronic chips temperature of not exceeding 85°C. As a result, the noise and vibration level is reduced. In addition, the proposed cooling system saved about 65% of the CPU fan power.

The importance of communication is vital in wartime. The capability of having all the position information of the allied and enemy forces in a single Tactical Information Display System (TIDS), maintains a great advantage for deciding what to do before the enemy reacts. A Naval Information Distributing System (NIDS) is developed for building an effective communication infrastructure between the war ships. In the designed network, besides the mobile platforms (ships), some fixed platforms (land stations) are used to transfer the information coming from these mobile platforms to all the other platforms. To demonstrate the performance and effectiveness of the Naval Information Distribution System, a discrete event simulation model is developed on a Geographic Information System. The goal of this thesis is to describe and experimentally evaluate an effective and feasible information sharing and routing system for Navy.

The increasing demand for online commerce has led to an increasing demand of autonomous vehicles in the logistics sector. The work in this thesis aims to improve the obstacle detection of autonomous forklifts by using 3D sensor technology. Three different products were compared based on a number of criteria. These criteria were provided by Toyota Material Handling, a manufacturer of autonomous forklifts. One of the products was chosen for developing a prototype. The prototype was used to determine if 3D camera technology could provide sufficient obstacle detection in a warehouse environment. The determination was based on the prototype's performance in a series of tests. The tests ranged from human to pallet detection, and were aimed to fulfill all criteria. The advantages and disadvantages of the chosen camera is presented. The conclusion is that the chosen 3D camera cannot provide sufficient obstacle detection due to certain environmental factors.

Orientador: Hans Kurt Edmund Liesenberg<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação<br>Made available in DSpace on 2018-08-11T00:52:22Z (GMT). No. of bitstreams: 1 Kollross_Diogo_M.pdf: 31909718 bytes, checksum: 107b2440c38f63fc3880fa52f54ea0d7 (MD5) Previous issue date: 2007<br>Resumos: Sistemas reativos têm grande importância em muitas áreas da engenharia e da computação, mas a qualidade e maturidade das metodologias e ferramentas de apoio ao desenvolvimento deixam a desejar em relação às voltadas a sistemas transformacionais. Uma das metodologias de destaque é a Arquitetura Orientada a Modelos, onde os sistemas reativos são descritos por modelos que podem ser diretamente traduzidos em formas executáveis. A linguagem mais bem sucedida na modelagem de sistemas reativos é Statechart, que deu origem a variações como os diagramas de máquinas de estado do padrão UML e à linguagem Xchart. Essa linguagem é uma extensão de Statechart que introduz construções para controle de processos externos, história de ativações e hierarquização de eventos. Para superar as limitações da ferramenta já existente para edição de diagramas Xchart conhecida como Smart, foi desenvolvido o editor Sins (Sins 1s Not Smart), implementado como plugin para o ambiente integrado de desenvolvimento Eclipse. Com o editor Sins é possível editar os diagramas através de manipulação direta, diagramar a especificação automaticamente e gerar o código fonte correspondente na linguagem textual TEXchart. O algoritmo de layout implementado é uma variação do algoritmo de Sugiyama, modificado para melhorar a legibilidade do dia:grama ao garantir a consistência na apresentação de suas estruturas e gerar mapas semelhantes aos desenhados livremente<br>Abstract: Reactive systems have great importance in many areas of Engineering and Computing, but the quality and maturity of the development support methodologies and tools Iack when compared to those directed to transformational systems. One of the outstanding methodologies is Model Oriented Architecture, where the reactive systems are described by models that can be directly translated to executable form. The best succeeded language for modeling of reactive systems is Statechart, which is the origin of variations like state machine diagrams from the UML standard and the Xchart Language. This language is an extension of Statechart that introduces eIements for external process control, activation history and hierarchization of events. To overcome the limitations of the already existing tool for the edition of Xchart diagramas known as Smart, the Sins editor was developed (Sins Is Not Smart), implemented as a plugin for the Eclipse IDE. With the Sins editor it is possible to edit diagramas through direct manipulation, layout the specification automatically and generate the corresponding source code in the textual Language TEXchart. The implemented layout algorithm is a variation of the Sugiyama algorithm, modified for better legibility of the diagram by assuring consistency in the presentation of its structures and generation of layouts similar to those freely drawn<br>Mestrado<br>Sistemas de Computação<br>Mestre em Ciência da Computação

This thesis presents the effect of dispersion and Multi Access Interference (MAI) of optical fiber on the Bit Error Rate (BER) performance of a Direct Sequence Optical Code Division Multiple Access (DS-OCDMA) network by means of intensity modulation and optical receiver correlators. By using Matlab simulations, Signal-to-Noise Ratio (SNR) versus Received Optical Power (ROP) of an OCDMA transmission system can be evaluated with a so-called 7-chip m-sequence for different numbers of system users. This can be done for the ROP versus BER for various lengths of single mode optical fiber by taking into consideration the dispersion effect in the optical fiber. Matlab simulations can be performed in order to illustrate the reduction of the dispersion index gamma, or to visualize different scenarios, e.g., what amount of transmitted power is required in order to obtain a BER of 10-9 when the length of the optical fiber is increased.

Ökande sjukskrivningar och allt fler som lider av psykisk ohälsa är idag ett problem i Sverige. En aktör vars involvering kan förstärkas när det kommer till att främja hälsa är arbetsgivaren. Det övergripande syftet med denna studie var att få en djupare förståelse för hur arbetsgivaren kan hjälpas i sin roll i sjukskrivningsprocessen och för att motverka psykisk ohälsa. Detta gjordes i samverkan med digitalbyrån NetRelations i Stockholm för projektet Stöd för rätt sjukskrivning (SRS) som ägs av Sveriges Kommuner och Landsting. SRS har det övergripande målet att förbättra för alla inblandade i sjukskrivnings- och rehabiliteringsprocessen. Behoven som identifierats i denna studie togs fram för att vara till grund för hur SRS kan utvecklas med arbetsgiven som användare. En kvalitativ ansats valdes och en tematisk analys gjordes utifrån data från fem intervjuade chefer inom den privata sektorn i Sverige. Huvudresultatet är att arbetsgivaren för att kunna öka en individs arbetsförmåga och arbeta preventivt mot psykisk ohälsa har behov av (1) mer kunskap om sjukskrivning, (2) att enklare kunna identifiera när någon mår dåligt, (3) att få stöd för bedömning av insatser, (4) att få hjälp med kommunikation och samverkan och (5) att ha tillgång till verktyg och information riktad mot arbetsgivare. Behoven har stöd i tidigare forskning om vad som skapar en frisk arbetsplats och kan om tillgodosedda i framtiden innebära att anställdas arbetsförmåga ökar. För att arbetsgivare ska ta till sig information och stöd krävs utifrån resultatet att den är noga utformad för dessa som användare. Resultaten har en betydelse dels för det fortsatta arbetet inom SRS, men också för att visa på hur vi kan inkludera arbetsgivaren för att skapa ett friskare Sverige.

Människor använder sig allt mer av digitala hälsoplattformar, vilket gör att det genereras mängder av hälsodata från användarnas digitala aktiviteter. Syftet med detta examensarbetet är att med hjälp av en konceptdriven designforskning framställa ett designkoncept för att hantera denna stora mängd hälsodata. Målet med konceptet är att det ska skapa en möjlighet för individer att själva hantera och få tillgång till sin hälsodata som genereras, för att i sin tur även kunna utnyttja det till något meningsfullt.  Med hjälp av en metodologisk guide har konceptet utvecklats, för att ta fram teoretiskt förankrade egenskaper och sammanställa dem till ett koncept i form av en modell. För att få in extern kritik av konceptet involverades tio användare, vilket i sin tur ledde till revidering och kontextualisering av HealthLab. I resultatet presenteras slutgiltligt koncept av Healthlab. Konceptet ska fungera som en multiplattform vars syfte är att samla in externa hälsodata, för att användarna ska få in flera aspekter i deras träning, som ska i sin tur hjälpa till att bidra till en bättre träningsupplevelse. Det slutgiltiga resultatet av HealthLab är tänkt att vara en framtidsvision för att vägleda och väcka nya tankesätt hos forskare och designers.<br>People are increasingly using digital health platforms, which means that lots of health data is generated from users' digital activities. The purpose of this paper is to develop a design concept to manage this large amount of health data, with the help of concept-driven design research. The goal of the concept is to create an opportunity for individuals to manage and access their generated health data, in order to use it for something meaningful.  With the aid of a methodological guide, the concept has been developed, to create theoretically anchored qualities and to compile them into a concept in the form of a model. To get external criticism of the concept, ten users were involved, which in turn led to revision and contextualisation of HealthLab. In the result, a final concept model is presented of HealthLab. The concept will serve as a multiplatform whose purpose is to collect external health data so that users can get several aspects of their training, which in turn will contribute to a better training experience. The final result of HealthLab is intended to be a vision for the future to guide and awaken new ways of thinking among researchers and designers.

碩士<br>國立交通大學<br>機械工程系<br>89<br>Recently, with the continuing increase of CPU’s frequency and system power dissipation in notebook personal computers, high performance thermal solutions such as heat pipe, heat sink, thermal spreader, and fans have witnessed an increasing number of applications in the notebook personal computers. Among them, active heat sinks are main elements in heat transfer system of a notebook PC. Therefore, based on the consideration of heat transfer, cost and space in notebook PC, the optimum design of active heat sinks is a very important subject. The objective of this research is to study notebook personal computer CPU heat sinks by STAR-CD software. The numerical simulation is performed by considering a conjugate problem which solved both flow and heat transfer in air stream and heat conduction in the fins of heat sinks. Simulation results showed local, average heat transfer coefficients of the fin and distribute temperature from bottom to top of fin. Secondly, based on the consideration of volume, cost, and dissipation of heat sinks, an optimum design, under various demands of heat—transferred amount of 13,17,21,25watts power of CPU individually, is explored by theoretical analysis to decrease the temperature generated from CPU. The results offered better references in designing heat transfer system in notebook PC.

碩士<br>國立交通大學<br>機械工程系<br>88<br>With the continuing increase of CPU and system power dissipation in notebook personal computers, high performance thermal solutions such as heat pipe, heat sink, thermal spreader, and fans have witnessed an increasing number of applications in the notebook personal computers. But notebook power consumption has been increasing rapidly; cooling techniques to remove the heat generated within the notebook have been evolving relatively slowly. This paper describes various cooling solutions using heat pipes for cooling of notebook personal computer. Namely, (1) heat pipes with heat spreader plate. (2) heat pipes with heat sink and fans. For transient heat transfer problem with uniform initial temperature, the Laplace transformation method is considerably powerful. However, it is difficult and complicated to solve the inverse transform of the subsidiary equation of the given differential equation. The technique of Fourier series can be used in order to obtain the inverse transform. The aim of this research is to analyze the cooling system of notebook personal computer. Using Laplace transform and finite Fourier’s series attempted a solution of governing partial equation for transient conduction in a medium. This solution procedure was a continuous form. The solution can be used to compute the temperature and flux distribution at any point throughout the medium. When increase velocity and size of heat spreader, heat dissipation increased effectively. In optimum design of heat sink, when heat flux approaches the maximum value, the ratio of fin thickness to fin spacing is about 1:1. The results of this work are presented in dimensional and dimensionless form for the convenience of parametric study and design analysis.

碩士<br>淡江大學<br>電機工程學系碩士在職專班<br>96<br>This thesis, based on Complex Programmable Logic Device (CPLD), mainly concerns with the design and implementation of a Fuzzy Logic controller (FLC) so as to adjust the fan speed via controlling the fan out driving circuit of a dc motor or shut down the system for protection when necessary. The information of the temperature of the system and the output voltage of the dc-motor fan out driving circuit are acquired by a thermal sensor and analog to digital (A/D) sensors. The major modules included in the FLC chip are fuzzifier circuit, rule-based circuit,inference engine circuit, and defuzzifier circuit, which, in response to different levels of temperature, carries out the designated fuzzy operations. This in turn produces a pulse width modulation (PWM) signal to adjust the dc-motor fan speed so as to remove the heat. This thesis presents a smart heat sink design for computer thermal fan speed control and system protection, which enables the system to work in a stable, efficient and quiet manner.

Increasing power dissipation and chip densities in the rapidly evolving electronics cooling industry are causing an ever increasing need for the tools and methods necessary for electronic systems design and optimisation. Modern electronic systems have the capacity to produce significant amounts of heat which, if not removed efficiently, could lead to component failure. The most common technique of heat removal is by making use of a heat spreader, or so¬-called heat sink. These devices are excellent heat conductors with a large surface area to volume ratio, and cooled through either natural or forced convection. Despite the advantages of these devices, there are serious consequences involved in the application of heat sinks. The required size of a heat sink may limit the miniaturisation of a product, while inadequate design, due to a lack of understanding of the flow physics, may lead to premature component failure. It is therefore crucial that an optimal heat sink design is achieved for every particular application. In the past, both heat sink design and optimisation have occurred mostly through experimental characterisation of heat sinks, which was not always particularly successful or accurate. Recent rapid developments in computer technology have led to the availability of various computational fluid dynamics or CFD software packages, with the capability of solving the discretized form of the conservation equations for• mass, momentum, and energy to provide a solution of the flow and heat fields in the domain of interest. This method of using the fundamental flow physics is currently the most complete way to determine the solution to the heat sink design and optimisation problem. It does unfortunately have the drawback of being computationally expensive and excessively time consuming, with commercial software prices being financially restrictive to the average designer. The electronics cooling community has subsequently identified the need for so-called "compact models" to assist in the design of electronic enclosures. Compact models use available empirical relations to solve the flow field around a typical heat sink. Current models require significantly less computational power and time compared to CFD analysis, but have the drawback of reduced accuracy over a wide range of heat sink geometries and Reynolds numbers. This is one of the reasons that compact modelling of heat sinks remain an international research topic today. This study has focused on the CFD modelling of a variety of forced flow longitudinal fin heat sinks with tip clearance. Tip clearance allows the flow to bypass the heat sink and downgrade its thermal performance. The flow bypass phenomenon, general flow behaviour, and pressure loss characteristics were investigated in detail. Thermal modelling of the heat sinks was left for future study. The flow information provided by the CFD analysis was combined with data available from literature to develop an improved compact flow model for use in a variety of practical longitudinal fin heat sinks. The new compact model leads to a 4.6 % improvement in accuracy compared to another leading compact model in the industry, and also provides more localised flow information than was previously available from compact modelling. <p The study therefore contributed significantly towards the general understanding and prediction of forced flow behaviour in longitudinal fin heat sinks with tip bypass, using both CFD analysis and the compact modelling approach. The new improved compact model may now be extended and incorporated together with the relevant flow details from the CFD analysis in a total package, solving for the flow and heat fields of forced flow longitudinal fin heat sinks. The study therefore assists in the global effort of making the confident and accurate use of compact modelling in modem electronic systems design and optimisation a practical reality.<br>Dissertation (M Eng (Mechanical Engineering))--University of Pretoria, 2007.<br>Mechanical and Aeronautical Engineering<br>unrestricted