An Exploratory Study on a Relationship between Changes in Cultivated Area of Major Crops and Farm Income by regions - From Comparative Analysis to Optimal Portfolio Analysis -

Jang, Ikhoon,Kim, Yeonjin,Choi, Dohyeong,Choe, Young Chan,Jung, Guhyun Korean Society of Food and Agricultural Informatio 2019 Agribusiness and Information Management Vol.11 No.1

This study is exploratory research on a relationship between changes in cultivated area of major crops and farm income by regions. We investigated level of income, volatility of income, and migration of suitable region by climate changes as factors influencing changes in cultivated area. Research processes are as follows. First, we classify the regions where cultivated areas are expanded or reduced through the trends of cultivated area by region and crop during recent 10 years. Second, we compare the changes in income related factors between groups during the same periods. Finally, the results from portfolio analysis show changes in stable income-based optimal crops. From these procedures, we found that the changes in cultivated area are not simply explained by income-related factors. In cases of vegetables, however, we also found that high volatility of income could contribute to reduce cultivated area of the crops. The results from portfolio analysis are not always consistent in all of cases. This means that crop selection can be decided by other factors than stable income.

An Exploratory Study on a Relationship between Changes in Cultivated Area of Major Crops and Farm Income by regions1 - From Comparative Analysis to Optimal Portfolio Analysis -

Ikhoon Jang,Yeonjin Kim,Dohyeong Choi,Young Chan Choe,Guhyun Jung 한국농식품정보과학회 2019 Agribusiness and Information Management Vol.11 No.1

This study is exploratory research on a relationship between changes in cultivated area of major crops and farm income by regions. We investigated level of income, volatility of income, and migration of suitable region by climate changes as factors influencing changes in cultivated area. Research processes are as follows. First, we classify the regions where cultivated areas are expanded or reduced through the trends of cultivated area by region and crop during recent 10 years. Second, we compare the changes in income related factors between groups during the same periods. Finally, the results from portfolio analysis show changes in stable income-based optimal crops. From these procedures, we found that the changes in cultivated area are not simply explained by income-related factors. In cases of vegetables, however, we also found that high volatility of income could contribute to reduce cultivated area of the crops. The results from portfolio analysis are not always consistent in all of cases. This means that crop selection can be decided by other factors than stable income.

천식환자가구를 통해 알아본 축축함 지수와 실내공기질의 연관성

김연진(Yeonjin Kim),이나경(Nakyung Lee),이지윤(Jiyoon Lee),장유리(Yuri Jang),한주희(Joohee Han),이정은(Jungeun Lee),박수정(Sujung Park),이상운(Sangwoon Lee),하세가와 겐이치(Hasegawa Kenichi),김성렬(Sungroul Kim) 한국생활환경학회 2021 한국생활환경학회지 Vol.28 No.4

Dampness deteriorates indoor air quality. This study aims at finding out the relationship between dampness score and levels of common indoor air quality indicators including CO₂, PM2.5, temperature, relative humidity and concentrations of indoor fungi. A survey was used to develop a dampness score and the indoor air quality was measured using a real-time indoor air quality sensing monitor (ESCORT, South Korea) and a collector for fungi measurement (KAS-110, Kemik Corporation, Seongnam, SouthKorea) among asthmatics’ home. A statistical package was used to evaluate the relationship between dampness score and indoor air quality variables. The spearman correlation coefficient between the dampness score and carbon dioxide was .642 indicating a strong correlation (p<.05). A significant correlation between the dampness score and the concentration of mold in the bedroom was also found ( .315, p<.05). The correlation coefficient between the dampness score and the relative humidity was .40 (p<.05). The correlation coefficients between the dampness score and PM2.5 or temperature were .02 or .014, respectively. This study found that dampness score was mainly determined by indoor CO₂, fungi concentration and relative humidity.

Construction of a Polyheterocyclic Benzopyran Library with Diverse Core Skeletons through Diversity-Oriented Synthesis Pathway

Oh, Sangmi,Jang, Hwan Jong,Ko, Sung Kon,Ko, Yeonjin,Park, Seung Bum American Chemical Society 2010 Journal of combinatorial chemistry Vol.12 No.4

<P>In this study, a divergent and practical solid-phase parallel diversity-oriented synthesis (DOS) strategy was successfully applied for the construction of five discrete core skeletons embedded with privileged benzopyranyl substructure. The diversity of these core skeletons was expanded through the introduction of various substituents at the R, R(1), and R(2) positions from a single key intermediate in five different pathways. More importantly, we efficiently maximized the molecular diversity through the transformation of the core skeleton itself by using the library-to-library concept and created a distinctively different collection of small molecules with the same building blocks. A 434-member polyheterocyclic benzopyran library was constructed on a scale of about 10 mg with the potential for further diversification. Without further purification, the average purity of the library is 85%.</P>

The Applicability of the Cultural Management Studies for International Tourism Researches

Minjoo Kim,Yeonjin Jang 관광경영학회 2002 관광경영연구 Vol.14 No.-

국제관광은 오래 전부터 관광학 연구의 주요분야로 인식되어 왔으나 아직 학적 체계를 이루지 못하고 있다. 기존에 수행된 국제관광 연구는 국제관광의 경제적 효과나 문화간 접촉에 따른 충격, 문화 변용 등의 한정된 관심에 머무르고 있으며, 관광경영 분야에는 몇몇 연구가 수행된 바 있으나 국내외적으로 주목할만한 연구를 찾아보기 어려운 실정이다. 본 연구는 이러한 문제의식 하에 국제화라는 시대적 조류 속에서 관광경영 연구가 실천적 유용성을 갖기 위한 지향점과 답보상태에 있는 국제관광 연구의 활로를 모색하기 위하여, 심리학, 경영학 등 다른 학문분야에서 이루어진 다문화 연구의 적용가능성을 탐색하였다. 그 동안에 축적된 다문화 또는 비교문화 연구들은 국제관광 현상을 설명하는 이론적 준거틀로 사용할만한 여지가 충분히 있으며, 국제관광의 거래 과정이 문화간 접촉을 수반한다는 점에서 관광산업의 조직행동 및 소비자행동 연구에 공헌할 수 있을 것으로 판단된다. 본 연구에서는 관광학 연구에 적용가능하며 다양한 명제를 도출할 수 있는 문화 연구들을 정리하기 위하여 기존의 문화 연구 중에서 다문화간 커뮤니케이션, 고유문화가 소비자 행동과 조직행동에 미치는 영향 등 비교적 미시적인 초점 하에 이루어진 연구들을 소개하고 응용가능성을 논의하였으며, 관광경영 분야에서 다루어진 비교문화 관련 연구도 요약 정리하였다. 본 연구는 광범위한 영역을 다루고 있어서 문화연구의 관광 분야 적용 가능성에 대한 세부전공별 논의가 미흡하고 실증적 연구가 아니라는 점에서 탐색적 연구들이 흔히 갖는 한계를 지닌다. 향후 이 분야에 관련하여 보다 진전된 연구들을 기대한다.

Multi-functional nitrogen self-doped graphene quantum dots for boosting the photovoltaic performance of BHJ solar cells

Moon, Byung Joon,Jang, Dawon,Yi, Yeonjin,Lee, Hyunbok,Kim, Sang Jin,Oh, Yelin,Lee, Sang Hyun,Park, Min,Lee, Sungho,Bae, Sukang Elsevier 2017 Nano energy Vol.34 No.-

<P><B>Abstract</B></P> <P>The tunable heteroatom doping density in graphene quantum dots (GQDs) can provide unique opportunities for advanced electrochemical and opto-electronic applications with control of intrinsic properties that allow exploiting new phenomena. Herein, we report a facile one-step synthesis of the nitrogen-doped high-crystallinity GQDs (nGQDs) from poly-acrylonitrile (PAN)-based CFs using the solvo-thermal cutting method. Interestingly, the optical properties of nGQDs can be simply controlled by varying the heat treatment temperature of the CFs with different N contents. We also conduct an in-depth study on the optical properties of nGQDs according to the variation of N atom density that can be readily modulated by controlling the graphitization temperature of CFs, via both experimental and computational analyses. The synthesized nGQDs are blended with PEDOT:PSS as an anodic buffer layer to induce efficient hole extraction and energy-down-shift in organic photovoltaic (OPV) devices that provide an enhanced power conversion efficiency (PCE) from 7.5% to 8.5%. Because of the wide absorption band, high carrier extraction, and non-toxicity, these nGQDs are demonstrated to be excellent probes for high-performance opto-electronic applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Facile one-step synthesis of the substitutional N-doped GQDs (nGQDs) from PAN-based carbon fibers (CFs), </LI> <LI> Regulating the concentration of heteroatoms and N-bonding configurations by altering the heat treatment temperature of CFs. </LI> <LI> As-prepared nGQDs have not only a high degree of optical tunability but also have outstanding crystallinity. </LI> <LI> Efficient down energy conversion and charge transport have been confirmed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Experimental Demonstration of in Situ Stress-Driven Optical Modulations in Flexible Semiconducting Thin Films with Enhanced Photodetecting Capability

Lee, Seung Min,Jang, Woosun,Mohanty, Bhaskar Chandra,Yoo, Jisu,Jang, Jin Woo,Kim, Da Bin,Yi, Yeonjin,Soon, Aloysius,Cho, Yong Soo American Chemical Society 2018 Chemistry of materials Vol.30 No.21

<P>Flexible semiconducting thin films have a broad coverage of future competitive electronic and optoelectronic devices. Although the stress present in thin films has been long known to affect optical properties, the experimental verification of the optical modulations in flexible systems has not been available so far. Here, we propose an in situ deposition process of inducing intentional compressive or tensile stress in the flexible thin films, ultimately to define the actual level of optical bandgap and photosensitivity modulations using an example of narrow bandgap p-type semiconductor of PbS thin films. We experimentally and theoretically prove the stress dependency of bandgap changes from 1.43 to 1.73 eV in the strain range of −0.88 to +0.88%. A metal-semiconductor-metal device with compressive strain-induced PbS thin film exhibited a higher photoresponse compared to the unstrained ones, because of combined effects of favorable band edge positions as well as generation of a higher number of electron-hole pairs due to absorption of a wider range of photon energies owing to its lower bandgap.</P> [FIG OMISSION]</BR>

Enhancing recurrent laryngeal nerve localization during transoral endoscopic thyroid surgery using augmented reality: a proof-of-concept study

Moon Young Oh*,Yeonjin Choi*,Taesoo Jang,Eun Kyung Choe,Hyoun-Joong Kong,Young Jun Chai 대한외과학회 2025 Annals of Surgical Treatment and Research(ASRT) Vol.108 No.3

Purpose: During transoral endoscopic thyroidectomy, preserving the recurrent laryngeal nerve (RLN) is a major challenge because visualization of this nerve is often obstructed by the thyroid itself, increasing the risk of serious complications. This study explores the application of an augmented reality (AR) system to facilitate easier identification of the RLN during transoral endoscopic thyroidectomy. Methods: Three patients scheduled for transoral endoscopic thyroidectomy were enrolled in this proof-of-concept study. Preoperative computed tomography scans were used to create an AR model that included the thyroid, trachea, veins, arteries, and RLN. The model was overlaid onto real-time endoscopic camera images during live surgeries. Manual registration of the AR model was performed using a customized controller. The model was aligned with surgical landmarks such as the trachea and common carotid artery. Manual registration accuracy was assessed using the Dice similarity coefficient (DSC) to evaluate the alignment between the real RLN and the RLN of the AR model. Results: The 3 patients included were female (mean age, 33.3 ± 15.7 years), and the mean tumor size was 1.0 ± 0.3 cm. All patients underwent transoral endoscopic thyroidectomy of the right lobe. Final histopathological diagnoses comprised 2 papillary thyroid carcinomas and one follicular adenoma. The manual registration accuracy was 0.60, 0.70, and 0.57 for patients 1, 2, and 3, respectively, with a mean value of 0.6 ± 0.1. Conclusion: The application of an AR system during transoral endoscopic thyroidectomy proved feasible and demonstrated potential for improving the localization of anatomical structures, particularly the RLN, as indicated by a moderate DSC.

컴퓨터교육 : 보안교육 ; NXT 기반의 염도센서 보정 알고리즘 연구

박병훈 ( Byunghoon Park ),장연진 ( Yeonjin Jang ),오영빈 ( Youngbin Oh ),서지민 ( Jimin Seo ),장명호 ( Myungho Jang ),김희주 ( Heeju Kim ),김석희 ( Seokhee Kim ),김동정 ( Dongjung Kim ),정대용 ( Daeyong Jung ),임종범 ( Jongbeom Li 한국컴퓨터교육학회 2013 한국컴퓨터교육학회 학술발표대회논문집 Vol.17 No.1

``나트륨의 과다섭취가 성인병의 요인이 된다``는 최근 연구 결과를 바탕으로 염분 섭취에 대한 관심이 증대 되면서 저염도 식품 등 염도 측정이 필요한 분야에서 염도 측정의 높은 정확도를 요구하고 있다. 본 연구에서는 기존 염도 측정과 관련된 분야의 연구 결과를 활용해서 NXT 기반의 염도센서를 제작하고, 제작한 염도센서에서 산출된 결과 값을 이용하여 저염도 측정 과정에서 발생할 수 있는 염도 측정의 부정확함을 개선하고자 한다. 이를 위해 NXT 기반의 염도센서에서 나오는 저항값을 토대로 정확한 염도값을 구하기 위한 보정 알고리즘을 연구하였고 이를 프로그래밍하여 구현하였다. 실험을 통해 저염도 구간에서의 염도측정의 정밀함을 개선하는 결과를 얻었다.

모형선 제작을 위한 다중 판 네스팅

최준호(Junho Choi),장연진(Yeonjin Jang),오민재(Min-Jae Oh) 한국정보통신학회 2024 한국정보통신학회논문지 Vol.28 No.3