• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.6
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• pp.476-483
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• 2009

Cosmic ray is composed of nuclear particles moving at a light speed. The cosmic ray affects the performance and the reliability of semiconductor devices by ionizing the semiconductor material. In this study, the radiation effects of protons, electrons, and photons, which compose the cosmic ray, on the GOS(Geostationary Orbit Satellite) were evaluated using the Monte-Carlo N-Particle code. The GOS was chosen due to the comparatively long exposure to the cosmic ray as it stays in the geostationary orbit more than 10 years. As the absorbed dose of semiconductor from electrons is much larger than those of protons, photons, and the secondary radiation, most of the radiation exposure of the semiconductors in the GOS results from that of electrons. When we compare the calculated absorbed dose with the radio-resistance of semiconductor, the Intel 486 of the Intel company is not suitable for the GOS applications due to its low radio-resistance. However RH3000-20 of MIPS and Motorola 602/603e can be applied to the Satellite when the aluminium shield is thicker than 3 mm.

• Korean Journal of Materials Research
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• v.21 no.12
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• pp.650-654
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• 2011

In this paper, the effects of conventional and newly developed elastomer modified underfill materials on the mechanical shock reliability of BGA board assembly were studied for application in mobile electronics. The mechanical shock reliability was evaluated through a three point dynamic bending test proposed by Motorola. The thermal properties of the underfills were measured by a DSC machine. Through the DSC results, the curing condition of the underfills was selected. Two types of underfills showed similar curing behavior. During the dynamic bending reliability test, the strain of the PCB was step increased from 0.2% to 1.5% until the failure circuit was detected at a 50 kHz sampling rate. The dynamic bending reliability of BGA board assembly using elastomer modified underfill was found to be superior to that of conventional underfill. From mechanical and microstructure analyses, the disturbance of crack propagation by the presence of submicron elastomer particles was considered to be mainly responsible for that result rather than the shear strength or elastic modulus of underfill joint.

• Journal of Power Electronics
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• v.11 no.2
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• pp.194-201
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• 2011

The air flow supplied to a fuel cell system is one of the most significant factors in determining fuel efficiency. The conventional method of controlling the air flow is to fix the oxygen supply at an estimated constant rate for optimal efficiency. However, the actual optimal point can deviated from the pre-set value due to temperature, load conditions and so on. In this paper, the maximum efficiency point tracking (MEPT) algorithm is proposed for finding the optimal air supply rate in real time to maximize the net-power generation of fuel cell systems. The fixed step MEPT algorithm has slow dynamics, thus it affects the overall efficiency. As a result, the variable step MEPT algorithm is proposed to compensate for this problem instead of a fixed one. The complete small signal model of a PEM Fuel cell system is developed to perform a stability analysis and to present a design guideline. For a design example, a 1kW PEM fuel cell system with a DSP 56F807 (Motorola Inc) was built and tested using the proposed MEPT algorithm. This control algorithm is very effective for a soft current change load like a grid connected system or a hybrid electric vehicle system with a secondary energy source.

• The Transactions of the Korea Information Processing Society
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• v.4 no.5
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• pp.1371-1379
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• 1997

Undetectable faults in a digital circuit are faults that no input patterms can detect.Identifying these faults in test geferation process is very time- consuming especially for sequential circuits .In this paper we present a new algorithm to identify unedtectable faults in sequential cirouits .In the alorithm. we identify uninitializable fip-flops and then, faults that prevent intialization of the fkip-flops(FPIs)are identified, finally propagation path of the FPI is checked. Time complexity of this algorithm is porportional to the product of the number of flip flops with at lest a self loop and the number of gates in the circuit. Experiments were performed on the ISCAS89 benchmark ciruits to show the feadibility of the proposed algorithm.We could identify large amount of undetectable faults(up to 50% of the number of flip-flops)in circuits with uninitializable flip-flops. Consider-ing that most of the time in test generation is cinsumed in identifying undetecatable faults, performance of test generator can be improved by using this algorithm as a pre-processing of test generation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.8
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• pp.1226-1237
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• 1993

For data transmission over strictly band-limited non-ideal channels, different types of filters with arbitrary responses are needed. In this paper. we proposed two efficient techniques for the design of such FIR filters whose response is specified in either the time or the frequency domain. In particular when a fractionally-spaced structure is used for the transceiver, these filters can be efficiently designed by making use of characteristics of oversampling. By using a minimum mean-squared error criterion, we design a fractionally-spaced FIR filter whose frequency response can be controlled without affecting the output error. With proper specification of the shape of the additive noise signals, for example, the design results in a receiver filter that can perform compromise equalization as well as phase splitting filtering for QAM demodulation. The second method ad-dresses the design of an FIR filter whose desired response can be arbitrarily specified in the frequency domain. For optimum design, we use an iterative optimization technique based on a weighted least mean square algorithm. A new adaptation algorithm for updating the weighting function is proposed for fast and stable convergence. It is shown that these two independent methods can be efficiently combined together for more complex applications.

• The KIPS Transactions:PartA
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• v.18A no.6
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• pp.265-270
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• 2011

Even though 32-bit ISA based microprocessors are widely used more and more, 16-bit ISA based processors are still being frequently employed for embedded systems. Intel 8086, 80286, Motorola 68000, and ADChips AE32000 are the representatives of the 16-bit ISA based processors. However, due to less expressiveness of the 16-bit ISA from its narrow bit width, we need to execute more 16-bit instructions for the same implementation compared to 32-bit instructions. Because the number of executed instructions is a very important factor in performance, we have to resolve the problem by improving the expressiveness of the 16-bit ISA. In this paper, we propose a new pair register allocation algorithm to enhance an original graph-coloring based register allocation algorithm. Also, we explain about both the performance result and further research directions.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.7
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• pp.26-33
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• 1999

In order to examine the effect of beam location n the performance of bridge type piozoresistive silicon accelerometer, three sensors having different location of beams were simulated by FEN(finite element method) and fabricated by RIE(reactive ion etching) and KOH etching method using SDB(silicon direct bonding) wafer, Results of the FEM simulation present that the 1st resonace frequency and Z axis sensitivity of each sensor are identical but the 2nd, and the 3rd resonace frequency and X, Y axis sensitivity are different. Even though the 1st resonance frequency and Z axis sensitivity measured from fabricated sensors do not perfectly coincide with each other, all 3 type sensors present 180 ~ 220N/G of Z sensitivity at 5 V supply voltage and 1.3 ~ 1.7kHz of the 1st resonance frequency and about 2% of lateral sensitivity.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.6
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• pp.51-58
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• 2002

In this paper, a 155/311 Mb/s MUX/DEMUX chip using ECL macrocell away has been developed with a single device. This device for a 2.5 Gb/s SDH based transmission system is to interleave the parallel data of 51 Mb/s into 155 Mb/s(or 311 Mb/s) serial data output, and is to interleave a serial input bit stream of 155 Mb/s(or 311 Mb/s) into the parallel output of 51 Mb/s. The input and output of the device ate TTL compatible at the low-speed end, but 100k ECL compatible at the high-speed end. The device has been fabricated with Motorola ETL3200 macrocell away The fabricated chip shows the typical phase margin of 180 degrees and output data skew less than 220ps at the high-speed end.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.215-220
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• 2006

오늘날 우리는 모바일 기기의 눈부신 성장과 보급으로 인해 누구나 손쉽게 모바일 게임을 즐길 수 있게 되었다. 많은 게임 제작 업체들은 모바일 게임개발에 총력을 기울이고 있고, 단말기 제조업체들 역시 게임 전용폰을 출시하는 등 모바일 게임에 대한 호응이 고조되고 있는 상황이다. 이는 모바일 게임이 시간과 공간적 개념을 뛰어넘는 이동성(Mobility)이라는 큰 장점을 가지고 있기 때문이다. 그러나 이러한 장점에도 불구하고 현재까지 모바일 게임의 컨텐츠는 기존의 다른 게임에 비해 그다지 큰 차별성을 가지고 있지 않다. 고스톱이나 단순한 퍼즐게임 등이 호응을 얻고 있기는 하지만 '이동성' 이라는 큰 장점을 살리기 위해서는 거 적극적이고 새로운 개념의 접근이 필요하기 때문이다. 더구나 요즘은 PSP 와 같은 막강한 휴대용 게임기가 등장하면서 휴대폰에서 즐기는 모바일 게임은 작은 화면이나 낮은 메모리 등의 한계로 인해 점점 더 그 자리를 내어주고 있는 실정이다. 그렇다면 '이동성'을 적극적으로 활용할 수 있는 모바일 개임 제작에 대한 새로운 접근방식은 어떻게 이루어져야 할까? 이를 위한 효과적인 방법으로 본 논문에서는 게임의 무대를 우리가 살고 있는 '현실-Reality'로 옮겨 올 것을 제안한다. 그렇게 되면 게이머는 모바일 기기가 가진 제약에서 벗어나 그 자신이 직접 현실세계를 배경으로 한 게임캐릭터가 되고, 물리적 이동에 따라 게임이 진행되는 전혀 새로운 방식의 모바일 게임을 경험할 수 있게 될 것이다. 현재 국내외적으로 이러한 실험적 시도가 조금씩 이루어지고 있기는 하지만 아직 호응은 그리 높지 않다. 그리하여 본 논문에서는 그러한 사례들을 조망하고 가장 효과적인 방법을 국내의 현실에 적합하게 적용할 새로운 모바일 게임의 방식을 제안하고자 한다. 연구사례로 제안 할 모바일 게임은 인터넷 미니홈피, GPS, 멀티미디어 메시지, 카메라 폰, 전자상거래의 기능을 통합하여 활용하는 'Dice Adventure Meeting'이라는 이름의 모바일 미팅 게임이며, 게임의 구체적인 시나리오를 살펴보면서 현실을 배경으로 한 새로운 모바일 개임의 제작에 대한 접근방법을 제시하고자 한다.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.26-32
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• 2006

다양한 정보기기들이 출현함에 따라 UI가 제품성공의 중요한 요인으로 부각되고 있다. 이러한 중요성을 인식하고 Microsoft, Nokia, HP, Motorola 등 해외 선진기업들은 UI 연구에 주력해 오고 있다. 국내 기업들도 2000년대부터 본격적으로 기업 내 UI팀을 구성하기 시작하여 점점 그 규모와 역할을 확대해 나가고 있지만, 개발시간의 촉박함, 체계적인 방법론에 대한 인식 부족, 전문인력부족 등으로 인해 UI업무가 효율적으로 진행되지 못하고 있다. 선진기업과 경쟁하기 위해서는 사용자 경험 측면에 대한 투자가 시급하며, 국내 UI전문가의 역할이 크게 요구되고 있는 시점이다. 따라서 기업 내 UI업무의 현주소를 파악하고 통합적인 고객체험 디자인을 목표로 하는 UI팀의 발전방향을 모색하고, 비전을 제시하는 것을 연구의 목적으로 삼는다. 본 연구의 방법으로는 문헌조사와 선행연구를 통해 UI, UX의 개념과 UI관련 조직의 구성과 역할을 살펴보고, 국내 모바일 및 전자제품 제조사, 유무선 인터넷을 기반으로 하는 컨텐츠 서비스 업체의 UI실무자를 대상으로 한 인터뷰와 설문조사를 통해 현재 기업 내 UI팀의 현황(조직구성, 업무의 범위 및 프로세스, 조직 내에서의 위상 등)을 분석하였다. 그 결과 다음과 같은 문제점들이 도출되었다. 첫째 조직구조상의 문제점, 둘째 업무 프로세스상의 문제점, 셋째 전문인력의 부족 등이다. 본 연구를 통해 기업 내 UI팀의 역할과 위상이 그 중요도에 비해 미약한 것으로 나타났다. 따라서 향후 통합적인 UX디자인을 접목한 미래 지향적 UI팀으로써 전체 프로세스 과정에 비전을 제시하기 위해서는 다양한 분야의 전문가들로 구성된 독립적 UI팀 구성이 이루어져야 한다. 또한 기획, 디자인, 개발 등 타 부서와의 보다 적극적인 업무교류를 통해 사용자의 입장을 대변하는 역할을 해야 한다.