• Journal of the Korea Society of Computer and Information
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• v.17 no.5
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• pp.9-19
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• 2012

As the clock frequency increases, CPU performance improves continuously. However, power and thermal problems in the CPU become more serious as the clock frequency increases. For this reason, utilizing the GPU to reduce the workload of the CPU becomes one of the most popular methods in recent high-performance computer systems. The GPU is a specialized processor originally designed for graphics processing. Recently, the technologies such as CUDA which utilize the GPU resources more easily become popular, leading to the improved performance of the computer system by utilizing the CPU and GPU simultaneously in executing various kinds of applications. In this work, we analyze the temperature and the energy efficiency of the computer system where the CPU and the GPU are utilized simultaneously, to figure out the possible problems in upcoming high-performance computer systems. According to our experimentation results, the temperature of both CPU and GPU increase when the application is executed on the GPU. When the application is executed on the CPU, CPU temperature increases whereas GPU temperature remains unchanged. The computer system shows better energy efficiency by utilizing the GPU compared to the CPU, because the throughput of the GPU is much higher than that of the CPU. However, the temperature of the system tends to be increased more easily when the application is executed on the GPU, because the GPU consumes more power than the CPU.

• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.153-158
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• 2020

In this study, the thermal and stress analyses were performed by applying a temperature condition of 100℃ at CPU cooler model. The value of heat flux value is shown to be the most at the lower rod area. The upper part becomes, the smaller the heat flow rate. The highest temperature is shown at the bottom of the CPU cooler model. Overall, the upper part becomes, the smaller the temperature becomes. Based on the temperature analysis, the thermal deformation caused by expansion, the deformation becomes smaller as the upper part of the overlapping plates. The great deformation happens at the bent area of the small rod as the lower part of model and the least deformation is shown at the lowest floor of model. In addition, the maximum thermal stress of 570.63 MPa happens at the floor below model. The stress is shown to decrease as the upper part of the overlapping plates becomes. But the stress is shown to increase somewhat at the middle part of model. By applying the study result on the thermal and stress analyses of CPU cooler, this study is seen to be suitable for the aesthetic convergence.

• Journal of the Korean Data and Information Science Society
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• v.16 no.4
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• pp.871-877
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• 2005

The purpose of this paper is to identify the CPU temperatures on traffic processing between two servers system. To test this model, this research applies multi-generator and resource reservation protocol that produce various types of traffics. The empirical results indicate that $56^{\circ}C\mp9^{\circ}C$ of CPU temperature is suitable when 250-300 traffics with 10-15kb per a packet are supplied. And also, no jitter delay time is showed in these cases.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.4
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• pp.255-265
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• 2008

This paper presents the optimization process of evaporator for a vapor compression cooling system for high heat flux CPU. The CPU thermal capacity was given by 300W. Evaporating temperature and mass flow rate were $18^{\circ}C$ and 0.00182kg/s respectively. R134a was used as a working fluid. Channel width(CW) and height(CH) were selected as design factors. And thermal resistance, surface temperature of CPU, degree of superheat, and pressure drop were taken as objective responses. Fractional factorial DOE was used in screening phase and RSM(Response Surface Method) was used in optimization phase. As a result, CW of 2.5mm, CH of 2.5mm, and CL of 484mm were taken as an optimum geometry. Surface temperature of CPU and thermal resistance were $33^{\circ}C\;and\;0.0502^{\circ}C/W$ respectively. Thermal resistance of evaporator designed in this study was significantly lower than that of other cooling systems such as water cooling system and thermosyphon system. It was found that the evaporator considered in this work can be a excellent candidate for a high heat flux CPU cooling system.

• Resources Recycling
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• v.25 no.6
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• pp.3-12
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• 2016

In this study, Au distribution in F-PGA chip and W-BGA chip were examined to recover Au effectively from CPU chips. The result showed that 80.8% and 89.8% of Au exist in terminal of F-PGA chip and bare die of W-BGA chip, respectively. Based on the fact that Au exists in specific parts of the chips, an CPU chip dismantling apparatus was developed. The experimental variables were roller rotating speed, heat temperature of IR heater and heating time. Terminals of F-PGA chips were completely recovered under the temperature of $300^{\circ}C$ and the residence time of 90 s. Bare dies of W-BGA chips were completely recovered as well under the temperature of $300^{\circ}C$, the roller rotating rate of 90 rpm and the residence time of 90 s.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.8
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• pp.821-828
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• 2012

Increasing heat generation in CPUs can hamper effective recirculation and by-pass because of the large temperature difference between the exhaust and the intake air through a server room. This increases the overall temperature inside a data center and decreases the efficiency of the data center's cooling system. The purpose of the data center's cooling system is to separate the intake and exhaust air by controlling the computer room air-conditioner(CRAC). In this study, ICEPAK is used to conduct a numerical analysis of a data center's cooling system. The temperature distribution and the entire room are analyzed for different volumetric flow rates. The optimized volumetric flow rate is found for each CPU power. The heat removal and temperature distribution for CPU powers of 100, 120, and 140 W are found to be the best for a volumetric flow rate of $0.15m^3/s$. The numerical analysis is verified through RTI indicators, and the results appear to be the most reliable when the RTI value is 81.

• Journal of ILASS-Korea
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• v.19 no.1
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• pp.19-24
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• 2014

In this study, the cooling performance of a liquid CPU cooler using the water/propylene glycol(PG)-based $Al_2O_3$ nanofluids is experimentally investigated. Water/PG-based $Al_2O_3$ nanofluids are manufactured by two-step method with ultrasonic energy for 10 hours. The volume fractions of the nanofluids are 0.25% and 0.35%. Thermal conductivity and viscosity of the nanofluids are measured to theoretically predict the thermal performance of the liquid CPU cooler using performance factor. Performance factor results indicate that the cooling performance of the liquid CPU cooler can be improved using the manufactured nanofluids. To evaluate the cooling performance of the liquid CPU cooler experimentally, temperature differences between ambient air and heater are measured for base fluid and nanofluids respectively. Based on the results, it is shown that performance of the liquid CPU cooler using $Al_2O_3$ nanofluids is improved maximum up to 8.6% at 0.25 Vol.%.

• Journal of Korea Multimedia Society
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• v.15 no.7
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• pp.920-930
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• 2012

In this paper, we designed and built a wired temperature controller system which is based on ASIC for a wireless temperature controller system based on FPGA. FPGA devices and wireless controller systems are growing quickly especially for industrial systems for sensing temperature and humidity. FPGA can set up a desired system and a CPU, and directly set up or change a peripheral device based on an IP quickly for an affordable price. This wireless system is easy to install in the field where there are lots of changes and the system is complex. It also has advantages for maintenance. In this study, we are using a 32 bit RISC CPU based on MicroBlaze, with a touch interface, peripheral device, and porting the embedded Linux. Also, we added wireless communication using ZigBee. With this system we provide remote monitoring and control through the web by adding a web server. Compared to the original system, we say not only a performance improvement, but also more efficient development and cheaper costs. In this study, we focused especially on building a better development environment and a more effective user interface.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.264-269
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• 2007

The microchannel waterblock has a good capability in the cooling of electronic devices. The object of this paper is to study on thermal performance of microchannel water block for cooling of CPU in desktop. The effects of header shape, liquid flow rate, and inlet temperature on the thermal performances of microchannel waterblock are investigated experimentally. Three types of waterblock with different header shape are manufactured from the micro milling and brazing processing. The experiments are conducted using water, over a liquid flow rate ranging from 0.7 to 2.0 LPM and inlet temperature ranging from 20 to $35^{\circ}C$. Waterblocks are attached both horizontally and vertically on the test section to anticipate a performance of waterblock under the actual state in computer. The base temperature and thermal resistance decrease with increasing of liquid flow rate. It was found that the sample #1 was appropriate for the prototype of liquid cooling system.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.1-2
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• 2020

비디오 서비스들이 등장함에 따라, 이를 위한 데이터 센터의 수요도 증가하였다. 이러한 데이터 센터의 서버들은 서로 다른 주변 온도를 보이는데, 높은 주변 온도는 높은 CPU 온도를 유도한다. 높은 CPU 온도를 낮추기 위해 CPU의 전압 및 주파수를 낮추는 온도 조절 정책이 수행되어 서버의 성능을 저하시킨다. 특히, 서로 다른 사양의 이기종 서버들에서는 주변 온도에 영향으로 인해 서버들의 성능이 역전될 수도 있다. 본 논문에서는 이기종 서버들에서 서로 다른 주변 온도가 서버의 성능에 미치는 영향을 중심으로 비디오 트랜스코딩 성능을 비교 분석한다.