리조트 시설의 형태적 특성에 관한 연구

서기영,이성창,이재혁 대한건축학회 2003 대한건축학회논문집 Vol.19 No.6

The purpose of this study is to provide the design method of the resort facilities to give proper visual characteristics. For this purpose, SD(Semantic Differential Scale) technique was conducted as the main research method and SPSS(Statistical package for the Social Sciences) program was applied for statistical analysis. The results are summarized as follows : (1) The visual factors of resort facilities are defined Harmony, Identification, Order, Entertainment, Decoration and Clearness. (2) There visual factors are closely related to Nature, Shape, Formation, Display, Ornament and Material. (3) Therefore, when planning and designing resort facilities, these relationship can be applied very usefully in systematic fashion.

Vibration suppression of a cantilever beam using magnetically tuned-mass-damper

Bae, Jae-Sung,Hwang, Jai-Hyuk,Roh, Jin-Ho,Kim, Jong-Hyuk,Yi, Mi-Seon,Lim, Jae Hyuk Elsevier 2012 Journal of Sound and Vibration Vol.331 No.26

전국해양문화학자대회(2009~2019)를 통해 본 해양관광 연구의 동향과 전망

이재혁(Yi, Jae-Hyuk) 국립목포대학교 도서문화연구원 2020 島嶼文化 Vol.0 No.56

그림자를 이용한 Mini-LED의 기울기 측정

이재혁(Jae-Hyuk Yi),김기승(Gi-Seung Kim),박윤창(Yoon-Chang Park) 한국산학기술학회 2023 한국산학기술학회논문지 Vol.24 No.8

본 논문은 그림자를 사용하여 Mini-LED의 기울기를 측정하는 방법을 제안한다. SMD의 일종인 Mini-LED는 주로 PCB에 일정 간격으로 실장되어 BLU 제작에 사용되고, 이러한 Mini-LED BLU는 LCD와 함께 TV와 모니터 제작에 사용된다. Mini-LED BLU에서 Mini-LED가 PCB에 경사져서 실장되면, Mini-LED의 가시광 조사 각도 또한 기울어지기 때문에 해당 Mini-LED 위치에서 디스플레이의 밝기 균일도가 저하 된다. 이러한 품질 저하를 방지하기 위해서 PCB에 실장된 Mini-LED의 자세를 검사하고, 불량 Mini-LED를 바로 잡아야 할 필요가 있다. Mini-LED에 사용될 수 있는 3D 측정의 경우, 대표적으로 모아레법과 PMP 방법이 고려될 수 있으나, Mini-LED 표면의 고반사 특성으로 인해 측정이 쉽지 않다. 또한 고반사 표면에 유리한 WSI 측정 방법은 세밀한 측정이 가능하지만, 생산현장에 적용하기에는 검사 시간이 너무 많이 소요된다. 따라서 산악과 건물의 높이를 측정하기 위해 사용되는 그림자를 이용한 측정 기술을 응용하여 Mini-LED의 기울기를 측정하는 방법을 제안한다. 제안된 방법은 2장의 이미지와 간단한 영상처리를 사용하여 Mini-LED의 기울기를 측정한다. 또한 이를 위해 흑백 카메라, 평행광 LED 조명 및 X-Y축 이송 시스템을 이용한 시스템이 고안되었다. 제안된 방법과 WSI 방법의 결과를 비교한 결과 X 방향 기울기 차이는 0.022~1.048도였으며, Y 방향 기울기 차이는 0.003~0.588도였다. Moiré methods and PMP methods are typically considered for 3D measurements that can be used for Mini-LEDs. However, measuring them is not easy due to the highly reflective nature of a Mini-LED surface. The WSI method is favorable for highly reflective surfaces and allows for detailed measurements, but it is too time-consuming for practical application in production environments. Therefore, a method is proposed for measuring the tilt of Mini-LEDs by using shadows, which is similar to the measurement of the heights of mountains and buildings. The proposed method employs two images and simple image processing to measure the tilts of Mini-LEDs. To achieve this, a grayscale camera, parallel LED illumination, and an X-Y axis translation system were used. The results of the proposed method were compared with those of the WSI method, which showed an X-direction tilt difference of 1.048 to 0.022 degrees and a Y-direction tilt difference of 0.588 to 0.003 degrees.

유격을 고려한 노즈 랜딩기어의 비선형 쉬미 해석

이미선(Mi-Seon Yi),황재업(Jae-Up Hwang),배재성(Jae-Sung Bae),황재혁(Jae-Hyuk Hwang) 한국항공우주학회 2010 韓國航空宇宙學會誌 Vol.38 No.10

본 논문에서는 유격을 고려한 항공기 전방 착륙 장치의 쉬미 현상을 연구하였다. 쉬미는 항공기의 이착륙 시 랜딩기어가 주행도중 측방향과 조향방향으로 진동에 놓이는 현상이다. 이 현상은 스트럿의 낮은 강성, 랜딩기어 내부의 마찰과 유격, 휠의 불균형이나 마모된 부품 등으로 인해 발생하며, 항공기의 안정성을 저하시킨다. 유격은 비선형 요소이기 때문에 기술 함수로 선형화 하여 주파수 영역에서 안정성해석을 수행하였고, 4차 Runge - Kutta를 이용하여 시간영역에서 안정성해석을 수행하였다. 본 연구에서는 수치적인 해석법을 통해 쉬미현상의 선형 동특성과 비선형 동특성을 조사하였다. 유격을 고려한 비선형 수치 해석결과, 선형 임계속도보다 낮은 속도에서 제한주기진동이 발생하는 등, 유격으로 인해 쉬미 안정성이 저감되는 결과를 관찰하였다. In this paper, we studied the shimmy phenomena of an aircraft nose landing gear considering free-play. Shimmy is a self-excited vibration in lateral and torsional directions of a landing gear during either the take-off or landing. This phenomena is caused by a couple of conditions such as low torsional stiffness of the strut, friction and free-play in the gear, wheel imbalance, or worn parts, and it may make an aircraft unstable. Free-play non-linearity is linearized by the described function for a stability analysis in a frequency domain, and time marching is performed using the fourth-order Runge-Kutta method. We performed the numerical simulation of the nose landing gear shimmy and investigated its linear and nonlinear characteristics. From the numerical results, we found limit-cycle-oscillations at the speed under linear shimmy speed for the case considering free-play and it can be concluded that the shimmy stability can be decreased by free-play.

전자기식 충격흡수구조의 설계를 위한 동특성 해석 및 실험

이미선,배재성,황재혁,임재혁,Yi, Mi-Seon,Bae, Jae-Sung,Hwang, Jae-Hyuk,Im, Jae-Hyuk 항공우주시스템공학회 2012 항공우주시스템공학회지 Vol.6 No.1

A shock absorber with magnetic effects is suggested for a lunar space-ship expected to launch in 2025. The device consists of a copper steel combined tube, two magnets, and a piston. The piston is designed to move a magnet through the tube when it is pushed by an external impact. While the magnet is moving in the tube, it generates the eddy current force with the copper part of the tube and it also makes the large friction force with the steel part of the tube. Beside, it gets resistive forces against its movement such as the magnetic force with a steel-ring at the first time of the movement and the repulsive force with a same pole opposed magnet at the end time of the movement. In this thesis, results of analyses and experiments of each force are represented and the expected performance of the electromagnetic shock absorber is drawn from the results.

한국멸종위기담수어종열목어(Brachymystax lenok tsinlingensis)의유전적 다양성과집단구조: 미래복원을위한보존의미a

Ji Eun Jang,Jae Hwan Kim,Ji Hyoun Kang,Song Yi Baek,Hwang Goo Lee,Jun Kil Choi,Jae Seok Choi,Hyuk Je Lee 한국환경생태학회 2016 한국환경생태학회 학술대회지 Vol.2016 No.1

Brachymystax lenok tsinlingensis (family Salmonidae), cold freshwater fish, is endemic to Asia. This species is currently distributed throughout Russia, Mongolia, China and the Korean Peninsula. B. lenok tsinlingensis in South Korea was severely affected by anthropogenic activities such as habitat destruction, agricultural run-off and water pollution, and hence this fish has recently been dramatically decreased in its population sizes and become now critically endangered. To recover the number of individuals of B. lenok tsinlingensis, stocking or translocation programs have been conducted continuously by local governments since 1970s. However, these programs made little effort to clarify populations that may have originated from stocked, translocated or introduced fish. An understanding of genetic characteristics of endangered populations is critical to develop effective conservation and restoration plans especially because genetic diversity ensues their future fate. Therefore, we assessed the “conservation status” of this species by estimating the level of genetic diversity and genetic structure among ten geographic populations including restored populations via reinforcement and supplementation. Also, we aimed to trace the genetic origins of the newly translocated population (Chiak) through a restoration practice program. Moreover, we inferred the phylogenetic relationships among Korean lenok populations as well as across the Northeast Asia. Two hundred eighteen individuals of B. lenok tsinlingensis were sampled from ten localities (Yanggu, Injae, Seorak, Bangtae and Hongcheon: North Han River basin; Pyeongchang, Chiak and Jeongseon: South Han River basin; Taebaek and Bonghwa: Nakdong River basin in South Korea). Based on mitochondrial DNA (mtDNA) control region and eight nuclear microsatellite loci, we found extremely low levels of within-population genetic diversity, which suggests small effective population sizes (Ne) within populations. For mtDNA control region, each population housed one, or at most, two haplotypes that are restricted to the respective localities, meaning that these ‘genetically unique’ lineages will be lost permanently if the local populations undergo extinction. The overall values of haplotype diversity (h) and nucleotide diversity (π) for the entire Korean population were 0.703 ± 0.024 and 0.021 ± 0.010, respectively. In the case of microsatellites, average number of alleles across the eight loci for the entire population was 9.1 and allelic richness (AR) per population ranged from 2.375 to 4.144 (mean = 3.104). The values of observed heterozygosity (HO) and expected heterozygosity (HE) were similar to each other [HO: 0.400 ~ 0.590 (mean = 0.518); HE: 0.407 ~ 0.608 (mean = 0.504)]. The inbreeding coefficient (FIS) values were generally low, ranging from 0.048 to 0.279. Consequently, the majority of the populations (except Yanggu and Pyeongchang) were not significantly deviated from Hardy-Weinberg equilibrium (HWE), suggesting random mating at these loci tested. In addition, we found that Korean lenok populations were significantly genetically isolated from each other, with private mtDNA haplotypes and microsatellite alleles, indicating limited gene flow among populations, strong effects of genetic drift due to small Ne, or a combination of both. The Mantel test of microsatellites revealed a significant correlation (r = 0.414, P = 0.04) between genetic and geographic distances for pairwise comparisons among the ten populations, while that of mtDNA showed a lack of correlation. Given the shared identical mtDNA haplotype and similar microsatellite allelic distributions between Chiak and Hongcheon populations, we suggest that the restored (introduced) Chiak population would be inferred to be genetically originated from Hongcheon population. Phylogenetic relationships among Northeast Asian populations showed that South Korean lineages have more recently diverged from China (Yellow River), than between North Korea and Russia. Although the phylogenetic relationship would be expected to be associated with geography, South-North Korea and China populations with a similar latitude was more phylogenetically closely related. These findings may suggest a possible scenario for the historical movements of B. lenok tsinlingensis in Northeast Asia during Last Glacial Maximum (LGM). It would be supported by the line of evidence that most lenok populations migrated to southward from Northern Asia such as Russia and Mongolia during LGM because the Korean Peninsula was landlocked as inland epoch and functioned as a southern shelter with Yellow River. For this reason, the Korean Peninsula is suggested to be an important geographical region for better understanding phylogenetic relationships and evolutionary histories of B. lenok tsinlingensis across the Northeast Asia. Despite large efforts made to develop several restoration programs in South Korea for B. lenok tsinlingensis, it is still unknown whether these past restoration efforts were successful or fruitless, mainly because of little attention paid to post-restoration monitoring research. Hence, there was a lack of their published official records. In the future, conservation and restoration projects of the Korean lenok populations should consider the genetic data for a better understanding of their ecological and evolutionary trajectories. And finally, we hope that our findings here can help inform on the future effective conservation and restoration plans for B. lenok tsinlingensis populatio ns in South Korea.

The Potency of Abamectin Formulations against the Pine Wood Nematode, Bursaphelenchus xylophilus

Jong-won Lee(Jong-won Lee),Abraham Okki Mwamula(Abraham Okki Mwamula ),Jae-hyuk Choi(Jae-hyuk Choi),Ho-wook Lee(Ho-wook Lee),Yi Seul Kim(Yi Seul Kim),Jin-Hyo Kim(Jin-Hyo Kim),Dong Woon Lee(Dong Woon L 한국식물병리학회 2023 Plant Pathology Journal Vol.39 No.3

Abamectin offers great protection against Bursaphelenchus xylophilus, a well-known devastating pathogen of pine tree stands. Trunk injection of nematicides is currently the most preferred method of control. This study aimed to evaluate the potency of the commonly used formulations of abamectin against B. xylophilus. Twenty-one formulations of abamectin were evaluated by comparing their sublethal toxicities and reproduction inhibition potentials against B. xylophilus. Nematodes were treated with diluted formulation concentrations in multi-well culture plates. And, populations pre-exposed to pre-determined concentrations of the formulations were inoculated onto Botrytis cinerea culture, and in pine twig cuttings. Potency was contrastingly different among formulations, with LC95 of 0.00285 and 0.39462 mg/ml for the most, and the least potent formulation, respectively. Paralysis generally occurred at an application dose of 0.06 μg/ ml or higher, and formulations with high sublethal toxicities caused significant paralysis levels at the tested doses, albeit the variations. Nematode reproduction was evident at lower doses of 0.00053-0.0006 μg/ml both on Botrytis cinerea and pine twigs, with significant variations among formulations. Thus, the study highlighted the inconsistencies in the potency of similar product formulations with the same active ingredient concentration against the target organism, and the need to analyze the potential antagonistic effects of the addi-tives used in formulations.

다발성 림프절종대를 동반한 정맥동 조직구증이 연관된 순수 적혈구 무형성증 1예

정재혁,서영배,최종현,박상민,최기영,김경천,배효근,이순,임재원 大韓血液學會 2000 大韓血液學會誌 Vol.35 No.3

Clinical practice guideline for the diagnosis and treatment of pediatric obesity: recommendations from the Committee on Pediatric Obesity of the Korean Society of Pediatric Gastroenterology Hepatology and Nutrition

Yi, Dae Yong,Kim, Soon Chul,Lee, Ji Hyuk,Lee, Eun Hye,Kim, Jae Young,Kim, Yong Joo,Kang, Ki Soo,Hong, Jeana,Shim, Jung Ok,Lee, Yoon,Kang, Ben,Lee, Yeoun Joo,Kim, Mi Jin,Moon, Jin Soo,Koh, Hong,You, Je The Korean Pediatric Society 2019 Clinical and Experimental Pediatrics (CEP) Vol.62 No.1

The Committee on Pediatric Obesity of the Korean Society of Pediatric Gastroenterology, Hepatology and Nutrition newly developed the first Korean Guideline on the Diagnosis and Treatment of Obesity in Children and Adolescents to deliver an evidence-based systematic approach to childhood obesity in South Korea. The following areas were systematically reviewed, especially on the basis of all available references published in South Korea and worldwide, and new guidelines were established in each area with the strength of recommendations based on the levels of evidence: (1) definition and diagnosis of overweight and obesity in children and adolescents; (2) principles of treatment of pediatric obesity; (3) behavioral interventions for children and adolescents with obesity, including diet, exercise, lifestyle, and mental health; (4) pharmacotherapy; and (5) bariatric surgery.