• 정보처리학회논문지A
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• 제13A권2호
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• pp.157-162
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• 2006

최근의 고성능 컴퓨팅 플랫폼들은 공유 메모리 다중 프로세서(SMP: Shared Memory Multiprocessor) 시스템, 대규모 병렬 프로세서 (Massively Parallel Processor) 시스템, 여러 개의 컴퓨팅 노드들을 연결한 클러스터(Cluster) 시스템 등으로 분류된다. 이러한 고성능 컴퓨팅 시스템들은 높은 수준의 컴퓨팅 성능을 요구하는 과학 기술용 응용 프로그램들을 위하여 사용된다. 이러한 응용 프로그램들의 실행시 최적의 성능을 얻기 위해서는 적절한 컴퓨팅 플랫폼과 프로그래밍 방식의 선택이 중요하다. 본 연구 논문에서는 여러 방식의 병렬 프로그래밍 모델을 사용하여 개발된 SPEC HPC2002 벤치마크 suite을 위한 최적의 컴퓨팅 플랫폼과 프로그래밍 모델을 그들의 성능 분석 및 평가 작업을 통하여 찾아간다.

• ETRI Journal
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• 제25권2호
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• pp.65-72
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• 2003

To achieve cost and size reductions, we developed a low cost manufacturing technology for RF substrates and a high performance passive process technology for RF integrated passive devices (IPDs). The fabricated substrate is a conventional 6" Si wafer with a 25${\mu}m$ thick $SiO_2$ surface. This substrate showed a very good insertion loss of 0.03 dB/mm at 4 GHz, including the conductive metal loss, with a 50 ${\Omega}$ coplanar transmission line (W=50${\mu}m$, G=20${\mu}m$). Using benzo cyclo butene (BCB) interlayers and a 10 ${\mu}m$ Cu plating process, we made high Q rectangular and circular spiral inductors on Si that had record maximum quality factors of more than 100. The fabricated inductor library showed a maximum quality factor range of 30-120, depending on geometrical parameters and inductance values of 0.35-35 nH. We also fabricated small RF IPDs on a thick oxide Si substrate for use in handheld phone applications, such as antenna switch modules or front end modules, and high-speed wireless LAN applications. The chip sizes of the wafer-level-packaged RF IPDs and wire-bondable RF IPDs were 1.0-1.5$mm^2$ and 0.8-1.0$mm^2$, respectively. They showed very good insertion loss and RF performances. These substrate and passive process technologies will be widely utilized in hand-held RF modules and systems requiring low cost solutions and strict volumetric efficiencies.

• Transactions on Electrical and Electronic Materials
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• 제17권6호
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• pp.317-328
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• 2016

Over the past few decades, CMOS current comparators have been used in a wide range of applications, including analogue circuits, MVL (multiple-valued logic) circuits, and various electronic products. A current comparator is generally used in an ADC (analog-to-digital) converter of sensors and similar devices, and several techniques and approaches have been implemented to design the current comparator to improve performance. To this end, this paper presents a bibliographical survey of recently-published research on different current comparator topologies for low-power and high-speed applications. Moreover, several aspects of the CMOS current comparator are discussed regarding the design implementation, parameters, and performance comparison in terms of the power dissipation and operational speed. This review will serve as a comparative study and reference for researchers working on CMOS current comparators in low-power and high-speed applications.

• Journal of Electrical Engineering and Technology
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• 제2권1호
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• pp.68-80
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• 2007

This paper covers switched reluctance generator (SRG) and its comparison with induction and synchronous machines for distributed generation. The SRG is simple in design, robust in construction, and fault tolerant in operation; it can also withstand very high temperatures. However, the performance and cost of the SRG power electronics driver are highly affected by the topology and design of the converter. IGBT and MOSFET based converters are not suitable for very high power applications. This paper presents thyristor-based resonant converters which are superior candidates for very high power applications. Operations of the converters are analyzed and their characteristics and dynamics are determined in terms of the system parameters. The resonant converters are capable of handling high currents and voltages; these converters are highly efficient and reliable as well. Therefore, they are suitable for high power applications in the range of 1MW or larger for distributed generation.

• 통상정보연구
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• 제18권1호
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• pp.209-233
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• 2016

최근 스마트폰을 포함한 각종 모바일 기기들은 여러 분야에서 전통적 개인용 컴퓨터를 차츰 대체해 나가고 있으며, 컴퓨터와 인터넷에 이은 새로운 컴퓨팅 패러다임을 구축해 나가고 있다. 그러나 PC와 다른 사용 환경과 모바일 기기의 하드웨어적 특성으로 인해 스마트폰 애플리케이션의 시스템, 정보, 서비스의 품질은 애플리케이션의 이용성(Usability)과 애플리케이션 이용을 통하여 얻을 수 있는 사용자의 개인적 성과(Performance)에 많은 영향을 미칠 것으로 예상된다. 이에 본 연구는 스마트폰의 물리적, 환경적 사용 여건에서 스마트폰 애플리케이션의 시스템, 정보, 서비스 품질이 애플리케이션의 이용성을 매개로 애플리케이션을 통한 사용자마다의 개인별 이용성과에 미치는 영향을 실증적으로 살펴 보았다. 최근의 애플리케이션 이용자를 대상으로 설문조사를 실시하였고 구조방정식을 통하여 자료를 분석하였다. 분석 결과 본 연구는 스마트폰 애플리케이션의 시스템, 정보, 서비스 품질이 애플리케이션의 지각된 이용성을 매개로 사용자의 애플리케이션 이용성과에 통계적으로 유의한 영향을 미치고 있음을 확인할 수 있었다.

• Computers and Concrete
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• 제23권6호
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• pp.459-470
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• 2019

Apart from strength properties, durability, toughness and workability are also important criteria in defining the performance of a concrete structure. Hence "High Performance Concrete (HPC)" is introduced. It is different from high strength concrete and can have various applications. In this paper, the properties (Mechanical and Durability) of High Performance Concrete blended with bagasse ash at 5%, 10%, 15% and 20% are studied. However, it is difficult to analyze the performance based on different properties obtained from different experiments. Hence it is necessary to combine all the criteria/properties into a single value to obtain a result by a technique called Analytical Hierarchy Process (AHP).It is an effective tool for dealing with complex decision making, and may aid the decision maker to set priorities and make the best decision. In addition, the AHP incorporates a useful technique for checking the consistency of the decision maker?s evaluations, thus reducing the bias in the decision making process.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.312-315
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• 2004

This paper presents a tuning-free conditional integration anti-windup strategy for induction machine with Proportional-Integral (PI) type speed controller. The on/off condition of integral action is determined by the frequency domain analysis of machine torque command without a prior knowledge of set-point changes. There are no tuning parameters to be selected by users for anti-windup scheme. In addition, the dynamic performance of the proposed scheme assures a desired tracking response curve with minimal oscillation and settling time even in the change of operating conditions. This algorithm is useful in many high performance induction machine applications not to allow the oscillation and overshoot of speed/torque responses. The main idea can be extended to general applications such as chemical processes and industrial robots.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.207-210
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• 2005

Ubiquitous computing is one of the key technology areas in the "Project on Development of Ubiquitous computing and network technology" promoted by the Ministry of Science and Technology as a frontier business of the $21^{st}$ century in Korea, which is based on the new concept merging physical space and computer-based cyber space. With recent advances in Micro Electro Mechanical System (MEMS) technology, low cost and low-power consumption wireless micro sensor nodes have been available. Using these smart sensor nodes, there are many activities to monitor real world, for example, habitat monitoring, earthquake monitoring and so on. In this paper, we introduce web-based real environment monitoring system incorporating wireless sensor nodes. It collects sensing data produced by some wireless sensor nodes and stores them into a database system to analyze. Our environment monitoring system is composed of a networked camera and environmental sensor nodes, which are called Mica2 and developed by University of California at Berkeley. We have modified and ported network protocols over TinyOS and developed a monitoring application program using the MTS310 and MTS420 sensors that are able to observe temperature, relative humidity, light and accelerator. The sensed data can be accessed user-friendly because our environment monitoring system supports web-based user interface. Moreover, in this system, we can setup threshold values so the system supports a function to inform some anomalous events to administrators. Especially, the system shows two useful pre-processed data as a kind of practical uses: a discomfort index and a septicity index. To make both index values, the system restores related data from the database system and calculates them according to each equation relatively. We can do enormous works using wireless sensor technologies, but just environment monitoring. In this paper, we show just one of the plentiful applications using sensor technologies.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.188-189
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• 2007

Conventional active-clamp forward converter shows good performance in low power applications, however it suffers from a high voltage stress of switch and is not suitable for high input voltage applications. To solve this problem, a new multi-level active-clamp forward converter is proposed in this paper. Utilizing low rating switches, the proposed converter features high efficiency and low cost promising for high input voltage applications.

• 융복합기술연구소 논문집
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• 제9권1호
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• pp.1-6
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• 2019

Matrix multiplication is a fundamental mathematical operation that has numerous applications across most scientific fields. In this paper, we presents a parallel GPU computation algorithm for dense matrix-matrix multiplication using OpenGL compute shader, which can play a very important role as a fundamental building block for many high-performance computing applications. Experimental results on NVIDIA Quad 4000 show that the proposed algorithm runs about 208 times faster than previous CPU algorithm and achieves performance of 75 GFLOPS in single precision for dense matrices with matrix size 4,096. Such performance proves that our algorithm is practical for real applications.