• Smart Media Journal
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• v.11 no.2
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• pp.77-83
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• 2022

The neuromorphic architecture uses a spiking neural network (SNN) model to derive more accurate results as more spike values are accumulated through inference experiments. When the inference result converges to a specific value, even if the inference experiment is further performed, the change in the result is smaller and power consumption may increase. In particular, in an AI-based IoT environment, power consumption can be a big problem. Therefore, in this paper, we propose a technique to reduce the power consumption of AI-based IoT by reducing the inference time by adjusting the inference image exposure time in the neuromorphic architecture environment. The proposed technique calculates the next inferred image exposure time by reflecting the change in inference accuracy. In addition, the rate of reflection of the change in inference accuracy can be adjusted with a coefficient value, and an optimal coefficient value is found through a comparison experiment of various coefficient values. In the proposed technique, the inference image exposure time corresponding to the target accuracy is greater than that of the linear technique, but the overall power consumption is less than that of the linear technique. As a result of measuring and evaluating the performance of the proposed method, it is confirmed that the inference experiment applying the proposed method can reduce the final exposure time by about 90% compared to the inference experiment applying the linear method.

• Tunnel and Underground Space
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• v.33 no.3
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• pp.109-125
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• 2023

Disposal repository for high-level radioactive waste secures its safety by means of engineered and natural barriers. The performance of these barriers should be tested and verified through various aspects in terms of short and/or long-term. KAERI has been conducting various in-situ demonstrations in KURT (KAERI Underground Research Tunnel). After completing previous experiment, a conceptual design of an improved in-situ experiment, i.e. K-COIN (KURT experiment of THMC COupled and INteraction), was established and detailed planning for the experiment is underway. Preliminary characterizations were conducted in KURT for siting a K-COIN test site. 15 boreholes with a depth of about 20 m were drilled in three research galleries in KURT and intact rock specimens were prepared for laboratory tests. Using the specimens, physical measurements, uniaxial compression, indirect tension, and triaxial compression tests were conducted. As a result, specific gravity, porosity, elastic wave velocities, uniaxial compressive strength, Young's modulus, Poisson's ratio, Brazilian tensile strength, cohesion, and internal friction angle were estimated. Statistical analyses revealed that there did not exist meaningful differences in intact rock properties according to the drilled sites and the depth. Judging from the uniaxial compressive strength, which is one of the most important properties, all the specimens were classified as very strong rock so that mechanical safety was secured in all the regions.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1759-1760
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• 2006

GPS 수신기에서 항법을 수행하기 위해서 신호탐색, 신호추적, 데이터 동기, 데이터 복조, 측정치 생성 및 위치 계산의 과정을 거쳐야 한다. TTFF(Time To First Fix)는 이러한 시간의 합으로 수신기의 성능을 나타내는 중요 평가지수 중의 하나이다. 일반적인 수신기의 TTFF는 80~90초인 것으로 알려져 있으며, 고속으로 운동하는 항체의 경우, 빠른 TTFF를 필요로 하므로 가장 긴 시간이 소비하는 신호탐색 과정의 시간을 줄여야 한다. 본 논문에서는 고속으로 운동하는 항체에서 GPS 신호의 코드 탐색 시간을 줄이기 위하여 다중 상관기 구조를 가지는 수신기를 설계 하고자한다. 설계한 수신기는 수신된 신호의 코드위상을 여러 개의 상관기에서 동시에 탐색하도록 다중 상관기를 구성하여 코드위상 검색에 소요되는 시간을 단축시킨다. 이를 검증하기 위하여 GPS 모의 신호 발생기를 이용하여 실험을 수행하였다. GPS 신호는 IF 데이터 수집 장치로부터 수집된 신호를 이용하며, 실험 수행 결과 다중 상관기를 이용하였을 때 TTFF가 단축되는 것을 확인하였다.

• The Korean Journal of Zoology
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• v.19 no.1
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• pp.7-14
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• 1976

The release of ovulatory level of LH from the pituitary gland occurred between 51 and 56 hours after PMS treatment in 24-day old female rats. Estradiol given simultaneously with PMS advanced LH release 24 hours. Injections of estradiol $(2.5\\sim 40\\mu g)$ at 0, 24 and 48 hours failed to increase pituitary LH level by 51 hours after the first injection in ovariectomized rats. However, $5 \\mu g$ estradiol at 0, 24 and 48 hours followed by 1 mg progesterone at 48 hours elevated pituitary L level by 51 hours in ovariectomized rats. These results indicate that advancement of PMS-induced ovulation by estradiol in the previous study occurred by means of inducing premature release of LH and estrogen might synergize with progesterone in the regulation of LH in the pituitary gland.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.443-446
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• 2019

빅데이터 분석을 위해 많이 사용하고 있는 기계학습 알고리즘들 중 딥러닝 알고리즘이 많이 활용되고 있으며 분류와 예측에 높은 정확도를 나타내고 있다. 딥러닝 알고리즘의 적용에 따른 많은 장단점들이 있지만, 단점은 분석에 사용되는 특징들이 너무 많다는 것과 분석 모델을 만드는데 사용되는 알고리즘도 여러 가지를 적용하다 보니 분석 시간이 오래 걸린다는 것이다. 이런 단점들은 업무를 파악하면 특징을 최소화할 수 있고 필요로 하는 정보만 선별해서 대표적인 딥러닝 알고리즘 하나에 분석을 하게 되면 분석 시간을 단축시킬 수 있다. 이 실험은 [1], [2]에서 연구한 영화 관객수 예측 모델을 4개의 특징으로 최소화하고 선별된 데이터를 인공신경망 알고리즘 하나로 예측 모델을 생성하였을 때 유의미한 정보를 도출해 낼 수 있는지를 알아보기 위한 것이다. 실험결과는 최종 관객수를 1명 단위까지 정확하게 예측하지는 못했지만 비슷한 수준의 관객수 정보를 예측하였다. 학문적인 접근으로 보았을 때 예측 정확도가 높지 않으면 사용이 불가능한 모델이라고 판단할 수 있지만, 기업 입장으로 접근해 보았을 때 예측 정보가 [1]. [2] 연구 결과에 비해 부족한 수준은 아니다. 총 소요된 시간은 기획 3일, 데이터 수집 및 모델 개발 5일, 분석 시간 10분으로 개발 시간 단축, 업무 효율성 향상, 비용 절감을 기대할 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.413-415
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• 2009

최근 지능형 로봇의 필요성과 활용성이 증가하면서 로봇의 형태와 사용 방법이 다양하게 발전하고 있다. 하드웨어적인 로봇의 발전은 과거부터 현재까지 많은 발전을 거듭해 왔으나, 로봇의 지능과 기능을 모듈화 하여 서비스 할 수 있는 방법은 많이 연구되지 못하였다. 지능로봇 서비스는 로봇의 형태와 사용 방법에 따라 서비스를 다르게 적용할 수 있을 뿐만 아니라, 다양한 응용 개발이 가능하여 쉽고 빠르게 로봇에 적용이 가능하다. 또한 컴포넌트 기반의 시뮬레이션 서비스를 개발함으로서 사용자(End User)의 설계 및 개발 시간 단축과 테스트 및 시뮬레이션 시간을 획기적으로 단축할 수 있다. 따라서 본 논문에서는 VPL 활용을 위한 지능로봇 시뮬레이션 서비스 컴포넌트 개발 연구 방법을 소개하고 제안한다. VPL은 인간친화적인 GUI환경으로 로봇 시뮬레이션 프로그램을 개발 할 수 있는 RDS 프로그램 방법이며, 다양한 서비스 개발을 통해 다양한 환경 그리고 다양한 시뮬레이션 로봇의 실험이 가능하다. 본 연구에서는 C# 언어를 사용하여 지능로봇 서비스 컴포넌트 개발 사례를 소개하고 실제 로봇 시뮬레이션 프로그램에 적용하여 실험하였다. 따라서 향후 많은 로봇 서비스 컴포넌트의 응용 개발과 로봇 산업, 교육 분야에 큰 도움이 될 것으로 기대한다.

• Journal of Korean Society of Steel Construction
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• v.24 no.4
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• pp.423-433
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• 2012

This paper summarizes full-scale gravity-load test results on CFT column-to-RC flat plate connections reinforced with shearhead. CFT construction has many structural and constructional advantages over conventional steel and RC column construction and is gaining wide acceptance. Meanwhile the use of RC flat plate system in the basement and residential floors of tall buildings is often mandatory to reduce story height and enable rapid construction in domestic practice. Combining CFT column and flat plate floor is expected to result in further rapid construction. However, the issues related to connecting CFT column to RC flat plate have not been fully addressed yet. Several promising connecting schemes by using steel shearhead were proposed and tested in this study. Test results showed that the proposed connection can exhibit the punching shear strength higher than RC flat plate counterparts. An empirical formula that can reasonably predicts the punching shear strength of the proposed connection was also proposed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5A
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• pp.426-435
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• 2005

this paper, we made out blocking probability analysis for a new authentication structure for reducing the certificate acquisition time which is one of the factors that should be improved in a conventional wireless PKI. A conventional key exchange method simply performs the key exchange setup step based on discrete algebraic subjects. But the mutual-authentication procedure of wireless PKI for reducing authentication time uses an elliptical curve for a key exchange setup step. Besides, we proposed advanced handover method and blocking probability analysis for wireless PKI. Proposed handover method shows reduced handover processing time than conventional method since it can reduce CRL retrieval time. Also, we compared proposed authentication structure and conventional algorithm, and simulation results show that proposed authentication method outperforms conventional algorithm in all environment regardless of call arrival rate, queue service rate, queue size

• Journal of the Korean GEO-environmental Society
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• v.13 no.5
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• pp.13-24
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• 2012

In this study, the in-situ model test has been conducted and used to estimate and analyze consolidation behavior of the ground by using the miniature test that reconstructs economically geotechnical behavior of in-situ full scale structure. To analogize the relation among effective stress, void ratio and coefficient of permeability at the self-weight consolidation stage, the low stress seepage consolidation test has been conducted and the involution function of constitutive equation had been obtained from the result of the curve fitted seepage consolidation test result. As a result of the numerical analysis that had been conducted on the representative section using a constitute equation, final settlement was similar with those of self-weight consolidation of the centrifugal model test. But, it was more or less smaller. It seems that these trends are caused by the difference between estimated values.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.2
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• pp.125-134
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• 2015

This is the third paper on the combustion characteristics of the landfill gas in a constant volume combustion chamber for a large displacement volume commercial engine. It is the first in this series to discuss the effects of the torch device on combustion. The results show that an optimum orifice ratio exists regardless of the torch volume, and a few adverse effects on the combustion are observed for an excessively small orifice ratio. In addition, the torch ignition decreases the initial burn duration, and the decrease in the heat transfer caused by this decreased duration contributes to an increase in the peak combustion pressure. Finally, the torch mostly plays a positive role in shortening the main burn duration when the combustion condition is worsened by a lower methane fraction. Yet, the torch decreases the initial burn duration rather than the main burn as the methane fraction increases.