• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.95-117
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• 2006

In this paper, we describe the optimization of the link-level performance and the complexity of floating-point and fixed-point methods in IEEE 802.16e OFDMA/TDD mobile modem. In floating-point design, we propose the channel estimation methods for downlink traffic channel and select the optimized method using computer simulation. So we also propose efficent algorithms for time and frequency synchronization, Digital Front End and CINR estimation scheme to optimize the system performance. Furthermore, we describe fixed-point method of uplink traffic and control channels. The superiority of the proposed algorithm is validated using the performances of Detection, False Alarm, Missing Probability and Mean Acquisition Time, PER Curve, etc. For fixed-point design, we propose an efficient methodology for optimized fixed-point design from floating-point At last, we design fixed-point of traffic channel, time and frequency synchronization, DFE block in uplink and downlink. The tradeoff between performance and complexity are optimized through computer simulations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.4002-4006
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• 2014

The automotive exhaust gases generated by the vehicles containing carbon monoxide, hydrocarbons and lead, is a large concern because of their harm to human health or the living environment. To reduce exhaust gas, it is important to develop a variety of techniques that are currently being used by elemental analysis to determine the optimal conditions. In this study, the anti-freeze coolant contained in the exhaust gas was examined, which can affect the emissions. The effects of the commercially available coolant from five domestic companies on the HC, NOx and $CO_2$ emissions were analyzed to determine the optimal amount of antifreeze. In addition, antifreeze products from the five companies were analyzed with respect to driving time of the cooling fan and the correlation of the NOx emission analysis. The temperature of the engine oil was matched using a manual gear of small passenger inspection standard speed $40{\pm}2Km/h$ so the vehicle could meet the specifications for inspection $90{\sim}93^{\circ}C$. The Company D fan operation time resulted in the shortest antifreeze, $CO_2$ and NOx emissions.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.301-305
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• 2007

The performance of polymer electrolyte membrane fuel cell could be decreased due to coolant leaked from connection part. Micro pump was used to put small amount of coolant and investigate the effect on fuel cell. The stoichiometric ratio of hydrogen/air was 1.5/2.0, both side of gas was fully humidified, and current density of $400mA/cm^2$ was used as standard condition in this experiment. Constant current method was used to check performance recovery from coolant effect in 3 cell stack. The performance was recovered when coolant was injected in cathode side. On the other hand, the performance was not recovered when coolant was injected in anode side. Ethylene glycol could be converted to CO in oxidation process and cause poisoning effect on platinum catalyst or be adhered on GDL and cause gas diffusion block effect resulting performance decrease. Water with nitrogen gas was supplied in anode side to check performance recovery. Polarization curve, cyclic voltammetry, electrochemical impedance spectroscopy was used to check performance, and gas chromatography was used to check coolant concentration. Constant current method was not enough in full recovery of performance. However, water injection method was proved good method in full recovery of performance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.12
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• pp.79-90
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• 2000

In this paper, a high-performance floating point unit, which is suitable for high-performance superscalar microprocessors and supports IEEE 754 standard, is designed. Floating-point arithmetic unit (AU) supports all denormalized number processing through hardware, while eliminating the additional delay time due to the denormalized number processing by proposing the proposed gradual underflow prediction (GUP) scheme. Contrary to the existing fixed-radix implementations, floating-point divide/square root unit adopts a new architecture which determines variable length quotient bits per cycle. The new architecture is superior to the SRT implementations in terms of performance and design complexity. Moreover, sophisticated exception prediction scheme enables precise exception to be implemented with ease on various superscalar microprocessors, and removes the stall cycles in division. Designed floating-point AU and divide/square root unit are integrated with and instruction decoder, register file, memory model and multiplier to form a floating-point unit, and its function and performance is verified.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.10a
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• pp.233-236
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• 1997

퍼지 관계 개념을 응용한 퍼지 정보 검색은 형태론에 입각한 기존의 정보 검색과는 달리 문서와 용어의 의미론에 근거하는 정보검색을 할 수 있다. 퍼지 정보 검색은 문헌의 집합 용어의 집합으로 나누고 문헌과 용어의 관계성을 문서 $\times$ 용어이 관계 행렬로 나타내며 퍼지 관계곱 연산을 이용하여 시소러스(thesaurus)를 형성하고 사용자로부터 주어진 질의 적합한 문서를 제공한다. 그러나 이러한 퍼지 관계곱 연산은 매우 큰 시간 복합도를 요구하는 연산이고 퍼지값은 부동소수점으로 표현해야하므로 대용량의 문서 시스템에 적용할 수 없어 비현실적이다. 부동소수점 연산은 연산속도가 느리고 저장공간도 많이 요구하므로 부동소수점 연산을 비트 연산으로 대체할 수 있다면 처리속도와 처리공간에 있어 성능 향상을 기대할 수 있다. 본 연구는 퍼지 정보 검색의 시소러스 형성에 있어 $\alpha$-cut 적용의 시기를 조정하여 성능을 향상하는 방법을 제안한다.

• Journal of the Korean Chemical Society
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• v.58 no.1
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• pp.9-16
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• 2014

In a borate buffer solution, the growth kinetics and the electronic properties of passive film on nickel were investigated, using the potentiodynamic method, chronoamperometry, and single- or multi-frequency electrochemical impedance spectroscopy. The oxide film formed during the passivation process of nickel has showed the electronic properties of p-type semiconductor, which follow from the Mott-Schottky equation. It was found out that the passive film ($Ni(OH)_2$) of Ni formed in the low electrode potential changes to NiO and NiO(OH) while the electrode potential increases.

• Journal of IKEEE
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• v.26 no.2
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• pp.240-248
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• 2022

Floating-point images that express pixel information as real numbers are used in HDR images. There have been various researches on efficient median filter algorithms, but most of them are applicable to 8-bit depth images and there are only a few number of algorithms applicable to floating-point images, including Gil and Werman's algorithm. In this paper, we propose a median filter algorithm that works efficiently on floating-point images by improving Kim's algorithm, which improved Gil and Werman's algorithm. Experimental results show that the execution time is improved by about 10% compared to the Kim's algorithm by reducing the redundant work for the repetitively used binary search tree and applying the inverted index.

• Journal of the Korean Geotechnical Society
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• v.19 no.2
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• pp.65-74
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• 2003

Most of land reclamation projects are being implemented along the south and west coastal lines of the Korean Peninsula. The earth structures and in-ground LNG tank, and buildings can be constructed using artificial freezing method on the reclaimed land to control the uplift pressure caused by capillary forces. In this study, upon freezing a saturated soil in a closed-system from the top, a considerable frost heaving pressure was developed. Decomposed granite soils, silty soil, and sandy soil were used in the laboratory freeze test which is sometimes subjected to thermal gradients under closed-systems. A major concern has been the ability to predict the frost heaving pressure over the results of relatively short-term laboratory tests. The frost heaving pressure arising within the soil samples and the temperature of the samples inside were monitored with time elapse. The degree of saturation versus heaving pressure curve is presented for each soil sample and the maximum pressure is closely related to this curve. TDR apparatus was used to measure the volumetric water content by the measurement of unfrozen water contents of frozen soils. Unfrozen water increased in soils containing a high percentage of fine-grained particles. In fine-grained soils with strong attractive farces between soil grains and water molecules, additional water is attracted into the pores leading to further volume changes and ice segregation.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.4
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• pp.24-29
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• 1983

In this paper, a floating-point processor which satisfied the subset of the proposed IEEE standard has been designed and realized by TTL chips. This processor consists of a floating-point arithmetic unit and a control sequencer. AHPL has been used in the design of sequencer. The execution times for the arithmetic operations were measured and compared with other microprocessor. The results had shown faster operations compared to the Z-80 processor. Though this processor was built by TTL chips, it could be fabricated as a one-chip processor.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.183-195
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• 2012

We propose a variable-latency Decimal Floating Point(DFP) adder which adopts the dual data path scheme. It is to speed addition and subtraction of operand that has identical exponents. The proposed DFP adder makes use of L. K. Wang's operand alignment algorithm, but operates through high speed data-path in guaranteed accuracy range. Synthesis results show that the area of the proposed DFP adder is increased by 8.26% compared to the L. K. Wang's DFP adder, though critical path delay is reduced by 10.54%. It also operates at 13.65% reduced path than critical path in case of an operation which has two DFP operands with identical exponents. We prove that the proposed DFP adder shows higher efficiency than L. K. Wang's DFP adder when the ratio of identical exponents is larger than 2%.