RPA분류기의 성능 향상을 위한 OHC알고리즘

이형일(Hyeong-il Lee) 한국멀티미디어학회 2003 멀티미디어학회논문지 Vol.6 No.5

700℃ 고온 배관에 Type 316L 스테인리스강의 적용성 분석

이형연(Hyeong-Yeon Lee),남기언(Ki-Eun Nam),윤정(Jung Yoon),김현일(Hyeong-Il Kim),어재혁(Jahyuk Eoh) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.11

Elevated temperature design and evaluations on Type 316L stainless steel piping in a 700℃ large-capacity thermal energy storage verification test loop (TESET) under commissioning at KAERI have been conducted. The hot leg piping with sodium coolant of 700℃ connect the main components of loop heater, hot tank and air-to-sodium heat exchanger. The design rules of ASME B31.1 and RCC-MRx provide design procedures for high-temperature piping in the creep range for Type 316L stainless steel. However, many material properties needed for design evaluations are not available over the temperature of 550℃ to 700℃. A series of high-temperature material strength tests were conducted in this study, and other essential material properties from previous test works on low cycle fatigue tests and creep tests were used for the design evaluations. The lack of material properties and design coefficients was determined based on the material tests associated with high-temperature design on the 700℃ piping. It was shown that Type 316L stainless steel can be used for a limited time duration in a high-temperature piping system of the TESET test facility subjected to 700℃ coolant.

열에너지 저장 시설의 Type 316L 스테인리스강 700°C 배관의 설계 및 건전성 평가

이형연(Hyeong-Yeon Lee),남기언(Ki-Eun Nam),윤정(Jung Yoon),김현일(Hyeong-Il Kim),어재혁(Jahyuk Eoh) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.5

Type 316L 스테인리스강의 700°C 고온 설계 물성 결정

이형연(Hyeong-Yeon Lee),남기언(Ki-Eun Nam),김현일(Hyeong-Il Kim),어재혁(Jahyuk Eoh) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.3

젤화 촉매의 종류 및 함량에 따른 경질 폴리우레탄 폼의 기계적 물성 변화

이형일(Hyeong Il Lee),이기윤(Kee Yoon Lee) 한국고분자학회 2015 폴리머 Vol.39 No.4

본 연구에서는 polyester계 polyol과 polymeric-methylene diphenyl diisocyanate(polymeric-MDI)를 사용하여 발포체를 형성할 때 아민계 젤화 촉매인 dimethylcyclohexyl amine(DMCHA)과 칼륨계 젤화 촉매인 potassium octoate(PO)가 발포체의 기계적 강도와 발포 셀의 분포에 미치는 영향에 대해 연구하였다. 첨가제로는 pentamethyl diethylene triamine(PMDETA) 촉매, 물, 발포제, 정포제를 사용하였다. 발포방식은 free rising test와 mold 공법을 사용하였다. Universal testing machine(UTM)을 통해 굴곡강도를 측정하였다. 굴곡강도는 free rising test의 경우 DMCHA 촉매의 함량에 따라 약 0.20에서 약 0.12 MPa로 감소하였으나 mold 공법의 경우 약 1.10에서 약 1.35 MPa로 증가하여 반대의 경향을 보였다. PO 촉매의 함량에 따른 영향도 DMCHA 촉매와 유사하였다. 또한 scanning electron microscope(SEM)으로 젤화 촉매의 함량에 따라 cell population density(CPD)가 증가하는 것을 확인하였고, 발포 셀의 크기 분포가 좁아지는 것을 확인하였다. The mechanical properties and the cell distributions of rigid polyurethane foams were studied on the effects of the contents of gelling catalysts of amine(dimethylcyclohexyl amine(DMCHA)) and potassium type(potassium octoate (PO)) after the processing of foaming with polyester polyol and polymeric-methylene diphenyl diisocyanate (polymeric-MDI). The additives such as pentamethyl diethylene triamine(PMDETA), water, blowing agents and surfactant were used. The processing methods of foaming were the free rising test and the expanding method in the mold. Flexural strengths were measured by the universal testing machine (UTM). As the contents of catalyst DMCHA increased, flexural strengths decreased from 0.20 to 0.12MPa at the free rising test. However they increased from 1.10 to 1.35MPa at the expanding method in the mold. Effects of flexural strengths on the contents of catalyst PO were similar with catalyst DMCHA. Also it was verified that cell population densities (CPD) increased and the cell size distributions became narrow as the contents of gelling catalysts increased.

강화학습을 이용한 다중 에이전트 제어 전략

이형일(Hyeong-il Lee) 한국멀티미디어학회 2003 멀티미디어학회논문지 Vol.6 No.5

정보이득 분할을 이용한 분류기법의 지배적 초월평면 생성기법

이형일(Hyeong-Il Lee) 한국컴퓨터정보학회 2014 韓國컴퓨터情報學會論文誌 Vol.19 No.1

중첩형 일반화 사례 (NGE, Nested Generalized Exemplar) 기법은 거리 기반 분류를 최적 일치 규칙으로 사용하며, 노이즈에 대한 내구력을 증가시켜 주는 동시에 모델 크기를 감소시키는 장점이 있다. NGE 학습 중 생성된 교차(cross)나 중첩(overlap) 현상은 분류성능을 저해하는 요인으로 작용한다. 따라서 본 논문은 NGE 학습 중 생성된 교차나 중첩 현상이 발생한 초월 평면에대해 상호정보가 가장 큰 구간을 분리하여, 새로운 초월평면을 구성하게 하여, 분류성능 향상시키고 초월평면의 개수를 감소시키는 기법인 DHGen(Dominant Hyperrectangle Generation) 알고리즘을 제안하였다. 제안한 DHGen은 분류성능면에서 kNN과 유사하고 NGE이론으로 구현한 EACH보다 우수함을 UCI Machine Learning Repository에서 벤치마크데이터를 발췌한 실험자료로 입증하였다. NGE(Nested Generalized Exemplar Method) can increase the performance of the noisy data at the same time, can reduce the size of the model. It is the optimal distance-based classification method using a matching rule. NGE cross or overlap hyperrectangles generated in the learning has been noted to inhibit the factors. In this paper, We propose the DHGen(Dominant Hyperrectangle Generation) algorithm which avoids the overlapping and the crossing between hyperrectangles, uses interval weights for mixed hyperrectangles to be splited based on the mutual information. The DHGen improves the classification performance and reduces the number of hyperrectangles by processing the training set in an incremental manner. The proposed DHGen has been successfully shown to exhibit comparable classification performance to k-NN and better result than EACH system which implements the NGE theory using benchmark data sets from UCI Machine Learning Repository.

차량용 터보차져의 소음도표 작성 및 응용

이형일(Lee, Hyeong-Il) 한국소음진동공학회 2010 한국소음진동공학회 논문집 Vol.20 No.5

A test facility which can simultaneously measure turbocharger operating condition variables and vibro-acoustic emission in the situations that are quite similar to real internal combustion engine operating conditions has been introduced. Using this facility, a new method sweeping from full open throttle to deep surge region along constant speed curves can be utilized instead of the stationary method that has been traditionally used to obtain turbocharger compressor maps. Data covering an extensive range of the compressor performance map have been collected and analyzed. An experimental study is performed to define a noise diagram that correlates vibro-acoustic measurements to aerothermodynamic operating conditions. An instrumentation set in the facility allows the automatic definition of the operating point on the turbine and compressor map of the turbocharger. Also, radiated sound pressure and casing vibration data corresponding to the point are obtained by a microphone in the vicinity of the compressor casing and an accelerometer on the casing. The major source(s) of noise at specific operating point on the map can be easily identified with these maps. Also, acoustic characteristics of a given turbocharger at the vicinity of the surge as well as in the surge are also defined. Finally, the possibility to define mild surge region of a turbocharger using vibro-acoustic measurements is studied.

초월평면 최적화를 이용한 최근접 초월평면 학습법의 성능 향상 방법

이형일(Hyeong-il Lee) 한국지능시스템학회 2003 한국지능시스템학회논문지 Vol.13 No.3

메모리기반 추론에서 기억공간의 효율적인 사용과 분류성능의 향상을 위하여 제안된 NGE이론에 기반한 최근접 초월평면법은 학습자료를 초월평면상에 투영시켜 생성된 초월평면을 이용한다. 이때 학습자료에 포합될 수 있는 오류자료가 그대로 초월평면에 포함되어 분류의 정확성을 저해하는 요인으로 작용하는 단점을 가지고 있다. 본 논문에서는 기존의 최근접 초월평면의 단점을 보완한 초월평면 최적화(OH : Optimizing Hyperrectangle) 방법을 제안한다. 제안된 방법은 특징가중치 벡터를 초월평면마다 할당하여 학습하고, 학습 후 생성된 모든 초월평면에 대해 특징별 최빈구간을 추출하여 최적초월평면을 구성하여 분류 시 사용한다. 제안된 방법은 EACH시스템과 마찬가지로 k-NN분류기에서 필요로 하는 메모리 공간의 40%정도를 사용하며, 분류에 있어서는 EACH시스템 보다 우수한 인식 성능을 보이고 있다. NGE (Nested Generalized Exemplars) proposed by Salzberg improved the storage requirement and classification rate of the Memory Based Reasoning. It constructs hyperrectangles during training and performs classification tasks. It worked not bad in many area, however, the major drawback of NGE is constructing hyperrectangles because its hyperrectangle is extended so as to cover the error data and the way of maintaining the feature weight vector. We proposed the OH (Optimizing Hyperrectangle) algorithm which use the feature weight vectors and the ED(Exemplar Densimeter) to optimize resulting Hyperrectangles. The proposed algorithm, as well as the EACH, required only approximately 40% of memory space that is needed in k-NN classifier, and showed a superior classification performance to the EACH. Also, by reducing the number of stored patterns, it showed excellent results in terms of classification when we compare it to the k-NN and the EACH.

복강내 방광파열의 치료에 있어 술 후 카테터 유치 방법간의 치료 효과 비교

이형일 ( Lee Hyeong Il ),김대곤 ( Kim Dae Gon ),하달봉 ( Ha Dal Bong ) 대한외상학회 2002 大韓外傷學會誌 Vol.15 No.2

Background : Primary bladder repair with a suprapubic catheter is considered to be effective for managing intraperitoneal bladder ruptures. We compared the outcomes obtained by using an indwelling suprapubic and urethral catheter together with those obtai