White-light Viewed from the Musical Perspective as Art Technology

Dongjae Lee,Wonhyung Lee 중앙대학교 영상콘텐츠융합연구소 2018 TechArt :Journal of Arts and Imaging Science Vol.5 No.3

Numerical Development of a Porous Medium Approach to Study Flow Characteristics in a Pin Fin Plate Heat Exchanger

Dongjae Kwon(권동재),Jonghyo Lee(이종효),Namkwon Lee(이남권),Sukkee Um(엄석기) 한국자동차공학회 2021 한국자동차공학회 학술대회 및 전시회 Vol.2021 No.11

Model Predictive Control for an Aerial Manipulator Opening a Hinged Door

Dongjae Lee,Dohyun Jang,Hoseong Seo,H.Jin Kim 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10

Aerial manipulation has been widely studied to be employed in various tasks such as exploration and transportation. To incorporate aerial manipulation into more sophisticated tasks like pulling or pushing a heavy cargo, an active interaction with surrounding structures should be considered. Unlike physical contact with a static structure which was mainly studied in previous papers, interaction with a movable structure requires a consideration of dynamics of the structure which makes the scenario more complex. In this paper, an aerial manipulator opening a hinged door is presented. Coupled dynamics between an aerial manipulator and a hinged door is derived, and a model predictive control (MPC) algorithm using iterative Linear Quadratic Regulator (iLQR) method for the derived dynamic equation is proposed. Through our proposed control strategy, sub-optimal state and input trajectories robust to model uncertainties while satisfying input constraints are generated. Our dynamic model and control algorithm are validated through simulations.

Dual-colour generation from layered colloidal photonic crystals harnessing “core hatching” in double emulsions

Lee, Jun Hyuk,Choi, Gwan H.,Park, Kyung Jin,Kim, Dongjae,Park, Juhyun,Lee, Seungwoo,Yi, Hyunmin,Yoo, Pil J. The Royal Society of Chemistry 2019 Journal of Materials Chemistry C Vol.7 No.23

<P>Colloidal photonic crystals (CPCs), which possess intrinsic colourization characteristics due to their internal periodic structure, have been extensively exploited for various optical applications. However, conventional droplet-based synthesis of CPCs has shown simple structure and mono-colour generating properties since they generally require a protective shell as the outermost confining layer, and the lattice spacing inside the CPCs is invariantly determined, which hinders further tunability for structural and optically responsive properties. To enhance the tunability for structural and optically responsive properties of CPCs, here, we present a means to induce a spontaneous core-hatching process of selectively removing the CPC-encapsulating oil layer in double emulsion droplets by harnessing interfacial instability. By virtue of the reinforced interconnectivity between colloidal polyvinylpyrrolidone (PVP)-decorated polystyrene (PS) nanoparticles, isolated CPCs can retain their structural integrity even without a protective outer shell. As a result, the hatched CPCs can be further re-ordered into a core-shell-like structure having dual internal spacings and dual-colour generation properties. PVP chains decorated on the PS nanoparticles dictate the lattice spacing not only through solvent swelling but also by imparting structural stability <I>via</I> formation of hydrogen bonds. Furthermore, the degree of hatching of CPCs can be modulated to either core-shell-like CPCs (complete hatching) or Janus-like CPCs (partial hatching). Therefore, the work presented here offers a new approach to create uniquely structured and multicoloured CPCs with stimulus responsiveness while fully utilizing the advantages of the double emulsion templating method.</P>

Correlation Between the Optical and the Structural Properties in SrZrO3 Nanocrystals

Lee Dongjae,이윤상 한국물리학회 2012 새물리 Vol.62 No.10

We used optical and photoluminescence spectroscopic techniques to investigate the optical and the structural properties of SrZrO_3nanocrystals (NCs) synthesized by using the combustion method. As-synthesized SrZrO_3 NCs were post-annealed at various annealing temperatures and under various ambient conditions. The absorption spectra of SrZrO_3 NCs are composed of a fundamental bandgap feature and an in-gap state just below it. With increasing annealing temperature, the bandgap of the NCs becomes larger, and the in-gap state absorption becomes weaker. At the same time, the violet-blue emission, which is clearly identified even at room temperature, is dramatically suppressed. These optical characteristics are in accord with the development of the peaks shown in the X-ray diffraction pattern with increasing annealing temperature. We also examined the possible contribution of the SrCO_3 impurity phase to the optical properties of the SrZrO_3 NCs.

Chronic osteomyelitis with septic arthritis caused by Scedosporium apiospermum

( Dongjae Lee ),( Sun Hee Park ),( Joonhong Park ),( Taijoon Ahn ) 대한내과학회 2015 대한내과학회 추계학술대회 Vol.2015 No.1

We present a rare case of chronic recurrent septic arthritis of knee joint with chronic osteomyelitis caused by Scedosporium apiospermum. A 67-year-old man was admitted to the hospital after sustaining degloving injury of left lower leg with a farm tractor. Wound infection followed injury and coryneform bacteria grew on wound culture of left leg. Despite repeated debridement and prolonged antibiotic therapy, knee swelling and pain recurred. Once infection signs and symptoms resolved after a year-long treatment, he underwent knee joint replacement surgery. One week after joint replacement, fluctuations were noticed on the lateral side of proximal tibia, then incisional debridement was performed. Wound culture of 4 different sites showed the growth of mould, which was later identified as Scedosporium apiospermum by using RNA sequencing of the 18s ribosomal RNA. It was presumed that S. apiosperum was inoculated when he sustained the injury. He received voriconazole without removing prosthesis and infection signsregressed. S. apiospermum is an unusual pathogen of bone and joint infection. Fungal joint infection is not easily diagnosed clinically and difficult to isolate the pathogen. Early diagnosis will reduce morbidity and mortality. Careful suspicion of fungal infection in case of recurrent chronic bone and joint infection will improve the prognosis of patients.

Recognizable-Image Selection for Fingerprint Recognition With a Mobile-Device Camera

Dongjae Lee,Kyoungtaek Choi,Heeseung Choi,Jaihie Kim IEEE 2008 IEEE Transactions on Cybernetics Vol.38 No.1

<P>This paper proposes a recognizable-image selection algorithm for fingerprint-verification systems that use a camera embedded in a mobile device. A recognizable image is defined as the fingerprint image which includes the characteristics that are sufficiently discriminating an individual from other people. While general camera systems obtain focused images by using various gradient measures to estimate high-frequency components, mobile cameras cannot acquire recognizable images in the same way because the obtained images may not be adequate for fingerprint recognition, even if they are properly focused. A recognizable image has to meet the following two conditions: First, valid region in the recognizable image should be large enough compared with other nonrecognizable images. Here, a valid region is a well-focused part, and ridges in the region are clearly distinguishable from valleys. In order to select valid regions, this paper proposes a new focus-measurement algorithm using the secondary partial derivatives and a quality estimation utilizing the coherence and symmetry of gradient distribution. Second, rolling and pitching degrees of a finger measured from the camera plane should be within some limit for a recognizable image. The position of a core point and the contour of a finger are used to estimate the degrees of rolling and pitching. Experimental results show that our proposed method selects valid regions and estimates the degrees of rolling and pitching properly. In addition, fingerprint-verification performance is improved by detecting the recognizable images.</P>

A Study of Musical Emotions with a Statistical Approach

Dongjae Lee,Wonhyung Lee 중앙대학교 영상콘텐츠융합연구소 2017 TechArt :Journal of Arts and Imaging Science Vol.4 No.2

Accuracy of genotype imputation based on reference population size and marker density in Hanwoo cattle

( Dooho Lee ),( Yeongkuk Kim ),( Yoonji Chung ),( Dongjae Lee ),( Dongwon Seo ),( Tae Jeong Choi ),( Dajeong Lim ),( Duhak Yoon ),( Seung Hwan Lee ) 한국축산학회 2021 한국축산학회지 Vol.63 No.6

Recently, the cattle genome sequence has been completed, followed by developing a commercial single nucleotide polymorphism (SNP) chip panel in the animal genome industry. In order to increase statistical power for detecting quantitative trait locus (QTL), a number of animals should be genotyped. However, a high-density chip for many animals would be increasing the genotyping cost. Therefore, statistical inference of genotype imputation (low-density chip to high-density) will be useful in the animal industry. The purpose of this study is to investigate the effect of the reference population size and marker density on the imputation accuracy and to suggest the appropriate number of reference population sets for the imputation in Hanwoo cattle. A total of 3,821 Hanwoo cattle were divided into reference and validation populations. The reference sets consisted of 50k (38,916) marker data and different population sizes (500, 1,000, 1,500, 2,000, and 3,600). The validation sets consisted of four validation sets (Total 889) and the different marker density (5k [5,000], 10k [10,000], and 15k [15,000]). The accuracy of imputation was calculated by direct comparison of the true genotype and the imputed genotype. In conclusion, when the lowest marker density (5k) was used in the validation set, according to the reference population size, the imputation accuracy was 0.793 to 0.929. On the other hand, when the highest marker density (15k), according to the reference population size, the imputation accuracy was 0.904 to 0.967. Moreover, the reference population size should be more than 1,000 to obtain at least 88% imputation accuracy in Hanwoo cattle.

Ad - Hoc 네트워크 환경에서 무선 TCP 성능 향상 기법

이동재(DongJae Lee),송주석(JooSeok Song) 한국정보과학회 2003 한국정보과학회 학술발표논문집 Vol.30 No.2Ⅲ

Ad-hoc 네트워크 환경은 자유롭고 예측할 수 없는 통신 노드들의 이동으로 인해 기본적인 TCP 혼잡 제어가 상당히 나쁜 영향을 미치게 된다. 기본적인 기본의 TCP에 대한 에러 감지(detection) 및 복구(recovery)는 새로운 환경에 맞추어 개선되어야 한다. 이 논문에서는 잦은 경로변경 현상을 네트워크의 피드백 없이도 패킷의 순서가 바뀌어 전달됨을 이용하여 알아내고, 이를 처리하여 성능을 향상시킬 수 있는 기법을 제안한다. 또한 오랜 시간의 네트워크 단절에 따른 성능감소문제를 수신자(Receiver)가 검사하여 해결할 수 있는 기법을 제안한다.