연구논문 : 철도교통소음의 특성에 관한 연구

최형일 ( Hyung Il Choi ),박상일 ( Sang Ill Park ),염동익 ( Dong Ick Yeom ) 한국환경과학회 2007 한국환경과학회지 Vol.16 No.7

A Matching Strategy to Recognize Occluded Number

최형일(Hyung-Il Choi),김계영(Gye-Young Kim),Thi Thuong Pham 한국컴퓨터정보학회 2011 한국컴퓨터정보학회 학술발표논문집 Vol.19 No.1

This paper proposes a method of occluded number recognition by matching interest points. Interest points of input pattern are found via SURF features extracting and matched to interest points of clusters in database following three steps: SURF matching, coordinate matching and SURF matching on coordinate matched points. Then the satisfied interest points are counted to compute matching rate of each cluster. The input pattern will be assigned to cluster having highest matching rate. We have experimented our method to different numerical fonts and got encouraging results.

컴퓨터 시각시스템에 있어서 매칭 및 제어전략에 관한 연구

최형일(Hyung-Il Choi) 한국인지과학회 1989 인지과학 Vol.1 No.2

깊이영상에서 실시간 얼굴 검출을 위한 I-MCTBoost

최형일(Hyung-Il Choi),원선희(Sun-Hee Weon),주성일(Sung-Il Joo) 한국컴퓨터정보학회 2014 韓國컴퓨터情報學會論文誌 Vol.19 No.3

본 논문에서는 실시간 얼굴 검출을 위한 부스팅 기반 분류 방법을 제안한다. 제안하는 방법에서는 조명과 얼굴크기 및 변형에 강건하게 얼굴을 검출하기 위해 깊이영상을 이용하고, 깊이차이특징을 사용하여 I-MCTBoost 분류기를 통해 학습 및 인식을 수행한다. I-MCTBoost는 약분류기로 구성된 강분류기들의 연결을 통해 인식을 수행한다. 약분류기의 학습 과정은 깊이차이특징을 생성하고, 이중에서 8개의 특징을 조합하여 약분류기를 구성하며 이때 각 특징은 2진비트(binary bit)로 표현된다. 강분류기는 정해진 약분류기의 개수만큼 반복적으로 약분류기를 선택하는 과정을 통해 학습이 이루어지며, 학습 과정에서 학습 샘플의 가중치를 갱신하고 학습 데이터를 추가하여 강건한 분류를 수행할 수 있도록 한다. 본 논문에서는 깊이차이특징에 대해 설명하고 이를 이용한 I-MCTBoost의 약분류기 학습 방법과 강분류기 학습 방법에 대해 제안한다. 마지막으로 제안된 분류기를 기존 MCT를 이용한 분류기와 정성적, 정량적 분석을 통해 비교하고 제안한 분류기의 타당성과 효율성을 입증한다. This paper proposes a method of boosting-based classification for the purpose of real-time face detection. The proposed method uses depth images to ensure strong performance of face detection in response to changes in lighting and face size, and uses the depth difference feature to conduct learning and recognition through the I-MCTBoost classifier. I-MCTBoost performs recognition by connecting the strong classifiers that are constituted from weak classifiers. The learning process for the weak classifiers is as follows: first, depth difference features are generated, and eight of these features are combined to form the weak classifier, and each feature is expressed as a binary bit. Strong classifiers undergo learning through the process of repeatedly selecting a specified number of weak classifiers, and become capable of strong classification through a learning process in which the weight of the learning samples are renewed and learning data is added. This paper explains depth difference features and proposes a learning method for the weak classifiers and strong classifiers of I-MCTBoost. Lastly, the paper presents comparisons of the proposed classifiers and the classifiers using conventional MCT through qualitative and quantitative analyses to establish the feasibility and efficiency of the proposed classifiers.

국소개선기법을 이용한 삼각격자 균질화

최형일(Hyung-il Choi),전상욱(Sangook Jun),이동호(Dong-ho Lee),이도형(Dohyung Lee) 한국항공우주학회 2005 韓國航空宇宙學會誌 Vol.33 No.8

본 연구에서는 삼각격자 균질화를 위하여, 확장된 위상학적 개선과정과 국소 최적화 기 반 평활화를 결합한 국소 개선기법을 제안하였다. 먼저 격자의 연결 구조를 확장된 위상 학적 개선과정을 적용하여 최적의 연결구조로 개선한다. 다음으로 격자의 질을 나타내는 비틀림척도를 최대화하기 위해 국소 최적화 기반 평활화를 수행한다. 이 국소 개선기법을 이용하여, 두 가지 격자 예제에 대하여 삼각격자 균질화를 수행하였다. 이 예들을 통하여, 본 연구에서 제안한 국소 개선알고리듬이 삼각격자의 질을 크게 향상시켜주는 경제적이며 효과적인 방법임을 보여준다. 또한, 이 기법은 적응격자 세분화의 격자 재생성과정에도 용이하게 적용될 수 있다. This paper proposes a local improvement method that combines extended topological clean up and optimization-based smoothing for homogenizing triangular grid system. First extended topological clean up procedures are applied to improve the connectivities of grid elements. Then, local optimization-based smoothing is performed for maximizing the distortion metric that measures grid quality. Using the local improvement strategy, we implement the grid homogenizations for two triangular grid examples. It is shown that the suggested algorithm improves the quality of the triangular grids to a great degree in an efficient manner and also can be easily applied to the remeshing algorithm in adaptive mesh refinement technique.

건설폐기물의 현장 재활용을 위한 공정개선 효과

최형일 ( Hyung Il Choi ),정경훈 ( Kyung Hoon Cheong ),채희정 ( Hee Jeoung Chae ),김연풍 ( Youn Poong Kim ),조도호 ( Do Ho Jo ),설동화 ( Dong Hwa Seol ),김정애 ( Jeung Ae Kim ) 조선대학교 공학기술연구원 2008 공학기술논문지 Vol.1 No.1

The conclusions of this study are summarized below: First, as a result of the evaluation of the mobility of the sorting and separating devices that are moved to and operated at the sites where construction waste is generated, very satisfactory results, namely about 2 days (13. 15 hr) to finish sorting and separating construction waste, were drawn. Second, 142.1 tons per hour were sorted and separated (treatment ability) on average. In terms of volume, about 32.6% of the treatment ability was higher than the suggested 80 ㎥/hr, at 106.1 ㎥/hr. Third, as a result of a grain test conducted on the 10~25 mm of recycled aggregates produced after injecting a good quality of sorted and separated waste concrete into the existing crushing and pulverizing process it was found that about 76.3% of the recycled aggregates remained in the 10 mm grains. For the absorption rate, 6.42% in the grains of less than 10 mm. 3.93% in the 10~25 mm grains, and 6.12% in the 25~40 mm grains were demonstrated. The moisture content was about 8.8% in the less than 10 mm grains, 4.74% in the 10~25 mm grains, and 6.11 % in the 25~40 mm grains. Fourth, in the case of operating sorting and separating devices for the on-site recycling of construction wastes, the noise level was found to be about 44.5~76.0 dB (A) around the target facilities and about 54.8~79.4 dB (A) within the working radius after measuring the levels of noise, vibration and dispersed dust, in view of the effort to minimize disputes and civil petitions deriving from noise, vibration and dispersed dust. The concentration of dispersed dust generated - when simultaneously operating the sorting process of the forward treatment for construction wastes and the production process for recycled aggregates - was about 0.089~0.707 mg/㎥ in the area around the facilities and was about 0.158~0.335 mg/㎥ at the site boundary. These levels actually met the permitted dust exposure level of 2~10 mg/㎥ of the first type to the third type of dispersed dust in relation to the working environment.

감성 인터페이스 에이전트

최형일(Hyung-Il Choi) 한국정보과학회 2000 정보과학회지 Vol.18 No.5

한 쌍의 실린더를 가지는 점성구동 마이크로 펌프의 성능 해석

최형일,조성찬,맹주성,Choi, Hyung-Il,Cho, Sung-Chan,Maeng, Joo-Sung 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.9

Since the viscous effect increases as the size of device decreases, viscous-driven micropump is a promising mechanism in microscale applications. In the present study, a dual-rotor type pump which contains two counter-rotating cylinders for improving performance characteristics is proposed. First, for flows in the single-rotor type pump, the present unstructured grid simulation method is validated by comparing its results to the previous results. Next, the performance of the dual-rotor type pump is evaluated by the parametric studies and is compared to that of the previous single-rotor type pump. The flow characteristics are qualitatively similar to those of single-rotor type pump. However, the performance of the micropump with tandem rotors is still better than that of previous pumping type, e.g. much larger flow rate, smaller driving region, higher efficiency, and wider operation range.

전 속도영역 유동을 위한 비정렬격자 압력기반해법

최형일,이도형,맹주성,Choi, Hyung-Il,Lee, Do-Hyung,Maeng, Joo-Sung 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.11

This article proposes a pressure based method for predicting flows at all speeds. The compressible SIMPLE algorithm is extended to unstructured grid framework. Convection terms are discretized using second-order scheme with deferred correction approach. Diffusion term discretization is based on structured grid analogy that can be easily adopted to hybrid unstructured grid solver. This method also uses node centered scheme with edge based data structure for memory and computing time efficiency of arbitrary grid types. Both incompressible and compressible benchmark problems are solved using the above methodology. The demonstration of this method is extended to slip flow problem that has low Reynolds number but compressibility effect. It is shown that the proposed method can improve efficiency in memory usage and computing time without losing any accuracy.

알루미늄 부식을 적용한 활성슬러지법에서 질소 및 인 제거

최형일,정경훈,박상일,백계진,Choi Hyung Il,Cheong Kyung Hoon,Park Sang Il,Paik Ke Jin 한국환경보건학회 2005 한국환경보건학회지 Vol.31 No.2

A laboratory experiment was performed to investigate simultaneous removal of phosphorus and nitrogen from raw sewage by intermittently aerated activated sludge process packed with aluminum and silver plate. Two continuous experimental process, i.e. an intermittently aerated activated sludge process, and an intermittently aerated activated sludge process with an aluminum and silver plate packed into the reactor were compared. The pitting corrosion of aluminum does not affect the performance of the biological treatment. The amounts of Al eluted from aluminum plate 17 mg to 60.6 mg in this experimental conditions, and Al/P mole ratio were from 3.31 to 11.25. The total nitrogen removal efficiency in Run E were $60.6\%$ at the HRT of 12 hours. The effluent $PO_4-P$ concentration as low as $1.0\;mg/\iota$ could have been obtained during the continuous experiment in Run E at HRT of 12 hours.