• Journal of the Korean Vacuum Society
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• v.22 no.2
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• pp.45-54
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• 2013

The cryopump of the pulse tube type has been developed successfully, and manufacturing of a prototype pump is finished under leading of Woosung Vacuum. The target pumping speed of the prototype pump is above 3,600 L/s for nitrogen with the intake port of 14 inches I.D (16 inches O.D). For designing optimally the pump structure including the charcoal array, thermal shield, and baffle, the pumping speed was simulated for various configurations through Monte Carlo method. Pumping performances of the protype cryopump manufactured on the basis of optimal design were conformed experimentally with a standard test system and procedures. The measured $N_2$ pumping speed of the prototype cryopump was 4,600 L/s which agreed well with simulated one and exceeded the target value.

• Journal of KIISE:Software and Applications
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• v.32 no.9
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• pp.920-926
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• 2005

Nearest neighbor algorithms classify an unseen input instance by selecting similar cases and use the discovered membership to make predictions about the unknown features of the input instance. The usefulness of the nearest neighbor algorithms have been demonstrated sufficiently in many real-world domains. In nearest neighbor algorithms, it is an important issue to assign proper weights to the attributes. Therefore, in this paper, we propose a new method which can automatically assigns to each attribute a weight of its importance with respect to the target attribute. The method has been implemented as a computer program and its effectiveness has been tested on a number of machine learning databases publicly available.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6B
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• pp.1203-1210
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• 1999

Coefficients of the adaptive filter are misadjusted by primary signals which are uncorrelated with reference signals of the adaptive filter. In this paper, the normalized sign algorithm is analyzed and compared with the NLMS algorithm by the steady state performance and the transient characteristics when target signals are included in primary signals. The excess mean square error of the NLMS algorithm is proportional to the power of target signals. That of normalized sign algorithm is proportional to the square root of the target signal power. However, the convergence speed of the normalized sign algorithm is slower than that of NLMS algorithm. In this paper, it is shown that theoretical analysis of the steady state performance and the transient characteristics are well consisted with the results of computer simulation.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.520-525
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• 1997

액체금속로의 안전성과 경제성을 향상시키는데 중요한 요소로 부각된 면진설계기술을 개발하기 위하여 고감쇠 면진베어링의 축소모델을 제작하고, 성능확인을 위한 다양한 시험을 실시하였다. 면진베어링의 성능을 나타내는 전단강성, 감쇠특성, 항복하중특성값, 전단변형능력 등에 대한 시험결과 전단강성은 목표값에 비하여 작았지만 감쇠값과 전단변형은 목표값에 근접하였다. 이를 이용한 면진 원자로건물의 지진응답을 분석한 결과 면진베어링은 건물의 지진응답 가속도를 대폭 줄여주는 것으로 나타났다.

• Journal of Korean Society of Steel Construction
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• v.18 no.5
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• pp.585-596
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• 2006

This study focuses on the seismic behavior of 3-, 9-, and 20-story steel moment resisting frame (MRF) structures designed in accordance with the 2000 International Building Code using different Response Modification factors (R factors), i.e., 8, 9, 10, 11, and 12. For a detailed case study, 30 different structures were evaluated for 20 ground motions representing the hazard level, which is equal to a 2% probability in 50 years (2% in 50 years). The results showed that the current R factors provide conservative designs for the 3- and 9-story buildings for the Collapse Prevention performance objective. the 20-story buildings, which were designed without using the minimum requirement of spectral acceleration CS prescribed in IBC 2000, did not satisfy the seismic performance for Collapse Prevention performance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.180-187
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• 2017

Major design targets such as test cell type, cell flow, cell bypass ratio, approach velocity, cell depression, front cell distortion, noise level and vibration level to construct a new 150,000 lbf thrust aircraft engine test facility were established. Based on the final aerodynamic and acoustic performance tests conducted at the newly constructed test facility, it was found that the new test facility is judged to be excellent and meets design targets.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.241-242
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• 2010

분산 Job Scheduling 문제에서 Makespan 은 항상 타 성능지표를 대표하는 단일 목표치 (Objective)가 되기 어려운 측면이 있다. 그러나 기존의 Job Scheduler 관련 제안들은 Makespan 만을 단일 목표치로 최적화 시킴으로써, 성능적 우수성을 입증하는 한계점이 있었다. 그러므로 본고에서는 Makespan 및 Throughput 을 동시에 최소화하여 개별 가중치로 정량화될 수 있는 다양한 성능 요구사항에 적합한 복수 대안 (Scheduling Alternatives)들을 제공할 수 있는 GA 기반 스케줄링 기법에 대해 제안한다.

• Annual Conference on Human and Language Technology
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• 2020.10a
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• pp.518-523
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• 2020

본 논문에서는 목적 지향 대화 시스템을 위한 대화 상태 추적 시스템과 사용자 시뮬레이터를 설계 및 제안한다. 사용자 시뮬레이터는 작성된 대화 상태 추적 시스템을 평가하기 위한 용도로 사용된다. 본 논문에서 제안하는 대화 상태 추적 시스템은 대화 기록과 함께 사전에 학습된 대화 기록 및 규칙/통계 기반 추론 시스템의 추론 결과를 입력으로 받는다. 그리고 입력된 발화 기록 중 마지막 사용자 발화의 사용자 목표와 개체명 그리고 다음 시스템 발화의 화행을 추론한다. 또한, 작성된 대화 상태 추적기의 성능을 평가하고 분석하기 위해, 주어진 환경에서 시스템과 대화를 수행하며 대화 시스템의 성능을 평가하는 사용자 시뮬레이터를 구현 및 적용하였다. 본 연구에서 수행된 실험과 분석을 통해, 규칙 및 통계 기반의 기반 시스템을 이용해 목표 시스템의 성능 개선이 가능함을 보인다. 또한, 제안하는 사용자 시뮬레이터는 규칙과 통계를 이용해 평가 코퍼스 없이 여러 상황에 대해 대화 시스템의 성능을 평가할 수 있다.

• Disaster Prevention Review
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• v.14 no.2
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• pp.61-62
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• 2012

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.11
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• pp.2131-2141
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• 2015

In this paper, we analyze ADC effect in IBFD system. Also, we design IBFD system with ADC effect, and evaluate BER performance of the system according to power of self-interference. Firstly, we describe a fundamentals of general IBFD system. And then we calculate and analyze characteristics of desired signal before and after ADC when residual self-interference is added to desired signal after RF cancellation. In this calculation, we have confirm some conditions for selection of # of ADC bit. Finally, we design IBFD system with ADC effect, and evaluate BER performance of the system by using Simulink simulation tool. As simulation results, we have confirmed that when power of residual self-interference is high before ADC, IBFD system must use high-bit ADC for decreasing quantization step. Also, we have confirmed that quantization step should be lower than one-third of amplitude of desired signal for effective communication with good performance.