Automatic CAD-structure extraction from 3D point clouds

Jihyeon Kwon,Nakju Lett Doh 한국정보통신학회 2015 2016 INTERNATIONAL CONFERENCE Vol.7 No.1

When we cannot use an original blueprint due to undocumented interior renovation or loss, we have measured and drawn structures manually. However, it is too time-consuming and inconvenient. Moreover, many objects placed in a room often occlude corners and edges of the room, which makes 3D indoor structure modeling more difficult. In this paper, we propose a new method for 3D indoor structure reconstruction which results in a simple CAD-structure with automatic process. For data collection of the indoor environment, we used a 3D laser sensor. For modeling structures, we classify the obtained 3D point clouds as structures and objects. Plane extraction among structure-PCD is followed since an extracted plane is intuitively part of a wall considering that indoor space is enclosed with walls. From the extracted planes, we seek points where three planes intersect since some intersection points are occluded by objects placed at the corner. Then several valid intersection points are determined as real structure points by the Plane-Patch test, eliminating other points that do not really exist. After that, we connect the valid structurepoints belonging to the ceiling, which creates a contour. With this, we can generate a floor plan of an indoor room. Considering the distance between the ceiling and the floor, finally, we reconstruct the 3D indoor structure as a simple CAD model. We applied this method to an indoor environment which consists of four rooms and obtained the results successfully.

저고도 무인기 교통관리 시스템 해외 기술 동향

권지현(Kwon, Jihyeon),홍성권(Hong, Sungkweon),은연주(Eun, Yeonju),전대근(Jeon, Daekeun) 한국항공우주연구원 2016 항공우주산업기술동향 Vol.14 No.2

드론을 활용한 다양한 산업분야의 성장과 낙관적인 경제 효과가 전망됨에 따라 앞으로도 급격한 드론 시장의 발전이 예상된다. 하지만, 드론 운용을 위한 교통관리 체계 미흡으로 안전, 사생활 침해 등의 문제가 대두되고 있다. 본 논문에서는 저고도 공역에서 안전하고 효율적인 무인기 운용을 위해 수립되고 UTM (Unmanned Aircraft System Traffic Management) 운용개념과 발전 로드맵을 해외 사례를 통해 파악해 보았다. 이를 통해, 우리나라 또한 실정에 맞는 저고도 무인기 교통관리 체계를 구축하여 드론의 적극적 활용을 기대해본다. With the growth of the various fields utilizing drones and the optimistic prospect of their economic effects, rapid development of the drone markets is expected. However, many problems such as security and privacy problems have been issued due to lack of traffic management for drone operations. In this paper, we surveyed the concept of operations for UTM (Unmanned Aircraft System Traffic Management) proposed by NASA and EASA for the secure and effective operations of drones in the low altitude airspace. The survey results will be used for the references to build Korean UTM system, which is a core infrastructure for the safe and efficient operations of drones in Korea.

OFDM 시스템에서의 IQ 불균형과 반송파 주파수 옵셋의 추정 및 보상 기법

권지현(Jihyeon Kwon),진영환(Younghwan Jin),안재민(Jaemin Ahn) 한국통신학회 2008 한국통신학회 학술대회 및 강연회 Vol.2008 No.4

Doped porous carbon nanostructure materials as non-precious metal catalysts for oxygen reduction reaction in alkaline and acid media

Kwon, Suk-Hui,Han, Sang-Beom,Kwak, Da-Hee,Song, JiHyeon,Park, Kyung-Won Elsevier 2019 Journal of industrial and engineering chemistry Vol.80 No.-

<P><B>Abstract</B></P> <P>Various doped porous carbon nanomaterials to replace Pt-based catalysts for oxygen reduction reaction (ORR) in acid and alkaline media have been intensively studied. Herein, doped porous carbon nanostructure materials as non-precious metal catalysts for ORR are synthesized using different weight ratios of polyaniline (PANI) to dicyandiamide (DCDA) as carbon source and dopants with iron salt to control the specific surface area and nitrogen doping content. The as-prepared samples exhibit well-defined porous carbon structure that consists of micro- and meso-pores, high specific surface areas, increased amount of nitrogen dopant, and relative content of graphitic N and pyridinic nitrogen N. Among these doped porous carbon nanostructure catalysts, the catalyst synthesized using a proper ratio of PANI to DCDA exhibits significantly improved electrocatalytic performance for ORR, i.e., high half-wave potential, high specific activity, and enhanced stability in both acid and alkaline media, because of the high graphitic N/pyridinic nitrogen N and micro-pore ratios.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Doped porous carbon nanostructures were synthesized using PANI and DCDA. </LI> <LI> The porous carbon nanostructures contained dopants such as Fe and N. </LI> <LI> The doped carbon nanostructures showed highly improved ORR activity. </LI> <LI> The improved properties were due to a well-doped porous carbon nanostructure. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

수신 신호의 연판정 값을 이용한 길쌈부호의 파라미터 암맹 판별 기법

이지현(Jihyeon Lee),권순희(Soonhee Kwon),신동준(Dong-Joon Shin) 한국통신학회 2019 韓國通信學會論文誌 Vol.44 No.11

Medial and Lateral Canthal Reconstruction with an Orbicularis Oculi Myocutaneous Island Flap

Han, Jihyeon,Kwon, Sung Tack,Kim, Suk Wha,Jeong, Eui Cheol Korean Society of Plastic and Reconstructive Surge 2015 Archives of Plastic Surgery Vol.42 No.1

Background The eyelid and canthal areas are common locations for cutaneous tumors. The medial canthus includes, among many other apparatuses, the canthal tendon and lacrimal canaliculi, and its characteristic thin and supple skin is hard to mimic and restore using tissue from other regions. Accordingly, reconstruction of the canthal area can prove challenging for surgeons. Although various methods, such as skin grafts and local flaps from adjacent regions, have been utilized for reconstructive purposes, they present known disadvantages. However, we were able to successfully reconstruct both lateral and medial canthal area defects by using orbicularis oculi myocutaneous island flaps. Methods Our study included seven patients who underwent medial or lateral canthal region reconstruction, using orbicularis oculi myocutaneous island flaps, between 2011 and 2014, following either cutaneous tumor excision or traumatic avulsion injury. Results Five patients had basal cell carcinoma, one had squamous cell carcinoma of the eyelid, and one had sustained a traumatic avulsion injury of the eyelid and canthal area. Entire flap loss was not observed in any patient, but one-a heavy smoker-showed partial flap loss, which healed with secondary intention and yielded acceptable results. Donor site morbidity was not observed, and all patients were satisfied with their surgical outcomes. Conclusions The canthal regions can be successfully reconstructed with orbicularis oculi myocutaneous island flaps. These flaps offer several key advantages, including similarity in texture, color, and thickness to the recipient site and a negligible incidence of donor site morbidity.

드론 영상의 객체 탐지 결과를 이용한 인파 밀집구역의 위험 지역 분석

송지현(Jihyeon Song),권영해(Younghae Kwon),유성재(Seongjae Yu),박재국(Jaekook Park) 대한공간정보학회 2023 한국공간정보학회 학술대회 Vol.2023 No.12

카이랄 나노소재의 광학 및 구조 분석법

권준영(Junyoung Kwon),염지현(Jihyeon Yeom) 한국고분자학회 2021 고분자 과학과 기술 Vol.32 No.3

광릉숲, 태화산, 가리왕산 활엽수림에서 낙엽에 의한 수종별 엽면적지수 추정

권보람 ( Boram Kwon ),전지현 ( Jihyeon Jeon ),김현석 ( Hyun Seok Kim ),이명종 ( Myong Jong Yi ) 한국농림기상학회 2016 한국농림기상학회지 Vol.18 No.1

광릉숲, 태화산 서울대 학술림, 가리왕산의 낙엽활 엽수림에서 연간 낙엽·낙지 생산량과 가을철 낙엽에 의한 수종별 엽면적지수를 산출하고, 간접적인 방법의 것과 비교하였다. 연간 낙엽·낙지 생산량은 천이 단계 증가에 따른 임분의 바이오매스 축적량이나 수종 구성 등에 따라 그 양과 비율이 다르게 나타났으며(Table 2), 특히 수종마다 낙엽의 양에 차이는 있지만 모든 임분에서 여름철 이후에 집중되는 경향을 보여(Fig. 1), 가을철의 한시적인 낙엽 수집만으로도 최대엽면적지수의 추정은 유효한 것으로 나타났다. 더욱이, 이러한 낙엽의 수집으로 낙엽의 양 뿐만 아니라 수종마다 SLA와 탈락시기를 정확하게 추정할 수 있었고 (Table 3), 간접방법으로는 불가능하기 때문에 국내에서는 시도되지 않았던 각 수종별 엽면적지수를 국내 최초로 산출 할 수 있었다(Fig. 2). 본 연구를 통하여 수종별 낙엽량과 엽면적지수는 각 수종의 흉고단면적과 유의한 상관관계를 보였으나, 간접방법에 의한 전체 엽면 적지수를 흉고단면적의 비율을 곱하여 수종별 엽면적지수로 추정하는 것은 상당한 오차가 발생할 수 있음을 알 수 있었다(Fig. 3). 또한 간접방법에 의한 엽면적지수는 잎의 양이 늘고 밀집도가 높아질수록 과소평가되는 오류가 발생하기 쉽기 때문에(Fig. 4, 5), 직접방법에 의한 엽면적지수와의 평가는 필수적임을 확인할 수 있었다. 따라서, 낙엽에 의한 직접적인 엽면적지수의 측정을 시도함으로써 다양한 수종이 공존하는 우리나라 온대 활엽수림에서 임분의 수종 구성과 밀도, 천이단계, 입지환경 등에 따른 낙엽량과 수종별 엽면적지수의 변화 양상을 정량적으로 확인 할 수 있었다. Annual litterfall production and leaf area index (LAI, m2/m2) were estimated using litter traps in Gwangneung, Mt. Taewha and Mt. Gariwang. Annual total litter fall production including branch, bark, others was the highest in Gwangneung(7497.3±326.5 kg/ha/yr), which had the highest basal area at late successional stage, and followed by Mt. Taewha(5929.1±225.8 kg/ha/yr) and Mt. Gariwang(3,210.1±220.1 kg/ha/yr). Mt. Gariwang had the lowest litterfall production due to high elevation and short growing season even with the higher stand density and basal area than Mt. Taewha. Similarly, LAI, which was calculated by multiplying the mass of leaf litter with specific leaf area, was the highest in Gwangneung(5.99±0.69) and followed by Mt. Taewha(5.20±0.24) and Mt. Gariwang(4.06±0.42) and the upper canopy species had the highest leaf area index in every sites (Gwangneung : 4.72, Mt. Taewha : 3.08, Mt. Gariwang : 2.19). However, species specific LAI estimation based on the relationship between basal area and leaf area was limited due to upper canopy species non-proportionality of basal area with LAI. In addition, the comparison between direct and indirect LAI measurement showed the importance of canopy clumping, especially at high density. Our study emphasized the necessity of direct LAI measurement using litter fall traps especially at temperate deciduous forest with diverse species.

Catalytic pyrolysis of waste printed circuit boards

( Hyunjin Kim ),( Jihyeon Seo ),( Haneul Shim ),( Youngeun Kang ),( Young-min Kim ),( Sumin Pyo ),( Young-kwon Park ) 한국폐기물자원순환학회 2022 ISSE 초록집 Vol.2022 No.-

Owing to the increased amount of electrical and electronic equipment, caused by the usage amount increase and further accelerated the exchange period of hardware, such as personal computer, smart phone, display equipment, and so on, the amount of electronic waste (e-waste) had been largely increased in recent decades. Printed circuit board (PCB) is a main component of electrical and electronic equipment and difficult to be recycled due to its harmful effect caused by the high halogen contents. In addition, the multilayer structure of PCB, consisted with additives, polymers, paper, and inorganics, makes it difficult to use the simple pyrolysis product as fuel or chemical feedstocks. Therefore, the catalytic pyrolysis was applied to increase the selectivity toward to the value-added products in this study. For the experiments, the tandem micro reactor-gas chromatography/mass spectrometry was used for the simple pyrolysis in the 1^st furnace and sequential catalytic upgrading of pyrolysis products in the 2^nd furnace. The product distribution produced at different temperature and by the use of different catalysts was analyzed and discussed to optimize the process operation for the chemical recycling of PCB. The obtained results suggested that the product oil quality can be increased by applying catalytic pyrolysis process increasing the yield of aromatic hydrocarbons with the decrease oxygen contents.