• 대기
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• 제27권2호
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• pp.133-150
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• 2017

This study evaluates CMIP5 model performance on rainy season evolution in the East Asian summer monsoon. Historical (1986~2005) simulation is analyzed using ensemble mean of CMIP5 19 models. Simulated rainfall amount is underestimated than the observed and onset and termination of rainy season are earlier in the simulation. Compared with evolution timing, duration of the rainy season is uncertain with large model spread. This area-averaged analysis results mix relative differences among the models. All model show similarity in the underestimated rainfall, but there are quite large difference in dynamic and thermodynamic processes. The model difference is shown in horizontal distribution analysis. BEST and WORST group is selected based on skill score. BEST shows better performance in northward movement of the rain band, summer monsoon domain. Especially, meridional gradient of equivalent potential temperature and low-level circulation for evolving frontal system is quite well captured in BEST. According to RCP8.5, CMIP5 projects earlier onset, delayed termination and longer duration of the rainy season with increasing rainfall amount at the end of 21st century. BEST and WORST shows similar projection for the rainy season evolution timing, meanwhile there are large discrepancy in thermodynamic structure. BEST and WORST in future projection are different in moisture flux, vertical structure of equivalent potential temperature and the subsequent unstable changes in the conditional instability.

• Structural Engineering and Mechanics
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• 제52권6호
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• pp.1193-1208
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• 2014

A simulation of failures on responsible elements is only one form of the extreme structural behavior analysis. By understanding the dynamic behavior in incidental situations, it is possible to make a special structural design from the point of the largest axial force, stress and redundancy. The numerical realization of one such simulation analysis was performed using FEM in this paper. The boundary parameters of transient analysis, such as overall structural damping coefficient, load accelerations, time of load fall and internal forces in the responsible structural elements, were determined on the basis of the dynamic experimental parameters. The structure eigenfrequencies were determined in modal analysis. In the study, the basic incidental models were set. The models were identified by many years of monitoring incidental situations and the most frequent human errors in work with heavy structures. The combined load models of structure are defined in the paper since the incidents simply arise as consequences of cumulative errors and failures. A feature of a combined model is that the single incident causes the next incident (consecutive timing) as well as that other simple dynamic actions are simultaneous. The structure was observed in three typical load positions taken from the crane passport (range-load). The obtained dynamic responses indicate the degree of structural sensitivity depending on the character of incident. The dynamic coefficient KD was adopted as a parameter for the evaluation of structural sensitivity.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1992년도 봄 학술발표회 논문집
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• pp.111-117
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• 1992

In order to design and construct a safe and economic underground structure, it is essential to understand the structural behavior of underground openings considering the effect of the sequential excavation. Therefore, this paper includes the study of initial stress distribution before excavation and stress redistribution due to the sequential excavation. And discussion on numerical simulation techniques for the sequential excavation is also included. Then, the underground structure is analyzed using the finite element and distinct element methods of analysis considering the effect of the sequential excavation. Based on the results of the analysis, the followings are discussed: shape of the openings, effect and timing of structural reinforcements. methods and sequence of excavation.

• 대한기계학회논문집B
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• 제32권11호
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• pp.878-883
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• 2008

The spray characteristics of a high pressure 6-hole injector were examined in a single cylinder optical direct injection spark ignition (DISI) engine. The effects of injection timing, in-cylinder charge motion, fuel injection pressure and coolant temperature were investigated using the 2-dimensional Mie scattering technique. It was confirmed that the in-cylinder charge motion played a major role in the fuel spray distribution during the induction stroke while the propagation of fuel spray was restrained during the compression stroke by the increasing pressure and the upward moving piston. In additions, it was confirmed that the liquid fuel droplets existing at the sprays edges were vaporized by the increase of the coolant temperature.

• The Journal of the Acoustical Society of Korea
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• 제23권3E호
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• pp.79-84
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• 2004

In this paper, the AEC(acoustic echo canceller) is designed and implemented using VHDL(VHSIC hardware description language). The designed Echo Canceller employs the pipeline and the master-slave structure, and is realized with FPGA. As an adaptive algorithm, the Normalized LMS algorithm is used. For the coefficient adjustment, the Stochastic Iteration Algorithm(SIA) which uses only current residual values is used and the number of registers are evidently reduced and convergence speed is also much improved comparing to existing methods by using EAB of FPGA for FIR filter structure of transceiver. The designed Echo Canceller is verified with the test board implemented for this paper. From the timing simulation echo signals at about 1500 sampling data are converged and ERLE is improved by about 42-dB.

• 대한전자공학회논문지SP
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• 제45권4호
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• pp.78-83
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• 2008

보간 필터는 샘플링된 데이터의 사이 값을 추정하는 회로로서 시간 복원 시스템에 널리 사용된다. 다항식 보간은 주어진 점의 정보를 가지고 각 다항식의 계수를 계산하여 추정하는 위치의 값을 계산하는 것이다. 본 논문에서는 Lagrange 3차 보간 방정식에서 주어진 계수를 제안한 ${\delta}$함수로 변환하는 보조 필터를 이용하여 보간 성능을 개선시키는 방법을 제안한다. 예제를 이용하여 제안한 구조와 기존 보간 회로 구조와 비교하였을 때 효율적임을 입증한다.

• 한국컴퓨터산업학회논문지
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• 제2권9호
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• pp.1183-1190
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• 2001

본 논문에서는 아날로그의 비디오 신호를 디지털로 부호화하는데 기존과 다른 파이프라인 방식을 사용하도록 하였다. 부호화기의 전체 동작을 화소 클럭비에 따른 파이프라인 구조로 설계하여 각 하위 블록들의 동작 타이밍을 확보하여 시스템을 안정화시켰으며 고정된 계수와 곱셈의 경우 기존의 ROM 테이블 또는 곱셈기 방식을 사용하지 않고 쉬프트와 덧셈기 방식으로 설계함으로써 시스템의 복잡도를 줄이며 논리 게이트 수를 15%줄이는 효과를 보였다. 설계된 부호화기는 각각의 하위 블록으로 나누어 VHDL로 설계하였고, Max+plusII를 이용한 FPGA로 동작 확인을 하였다.

• 인문언어
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• 제5권
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• pp.221-264
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• 2003

This paper takes issue with the idea of language as a 'serial-time structure' as opposed to the 'real-time event' of speech, an idea entrenched in Chomskyan model of linguistic theory. The discussion centers around the leitmotif question: Is language constructed entirely from a finite set of apriori discrete symbol types, as the 'competence vs performance' dichotomy implies\ulcorner A set of linguistic patterns examined in this study, largely with regard to phonological considerations, points to the evidence to the contrary. That is, while the patterns may be said to be linguistically distinct, they are not discretely, different, i.e. not different enough to be reliably differentiated. It is demonstrated that much of current research in phonology, including the most recent Optimality Theory, is misdirected in that it falsely presupposes a discrete universal phonetic inventory. The main thrust of the present study is that there is no sharp boundary between 'competence' defined as the formal, symbolic, discrete time domain of language and human cognition on the one hand and 'performance' as the continuous, fuzzy, real-time domain of human physiology on the other.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.585-588
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• 2007

We studied the effect of self-erase discharge on the luminous efficacy of ac PDPs. We observed through discharge current analysis to confirm that the selferase discharge occurred mainly between sustain cathode and address electrode, which have an influence on the luminous efficacy. The amount and timing of the self-erase discharge was varied to observe its effect on the luminous efficacy. It has been found that the luminous efficacy could be improved by the self-erase discharge when it is adjusted to occur right before the main discharge in the small gap structure. In the long gap structure, on the contrary, the luminous efficacy could be increased when the self-erase discharge is suppressed. Also, various waveforms to control self-erase discharge are suggested and tested in the panel experiments.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
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• pp.169-172
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• 2001

In this paper, it used a different pipeline method from conventional method which is encoding the video signal of analog with digital. It designed with pipeline structure of 4 phases as the pixel clock ratio of the whole operation of the encoder, and secured the stable operational timing of the each sub-blocks, it was visible the effect which reduces a gate possibility as designing by the ROM table or the shift and adder method which is not used a multiplication flag method of case existing of multiplication of the fixed coefficient. The designed encoder shared with the each sub-block and it designed the FPGA using MAX+PLUS2 with VHDL.