• Title/Summary/Keyword: Lee Sam

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Grid Method Applied for Establishing the Ecological and Natural Map: A Review Based on Results of Surveys of Endangered Mammals

  • Yong-Ki, Kim;Jeong-Boon, Lee;Sung Je, Lee;Jang Sam, Cho;Hyosun, Leem
    • Proceedings of the National Institute of Ecology of the Republic of Korea
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    • v.4 no.1
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    • pp.9-15
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    • 2023
  • We analyzed data of endangered mammals in the 1st grade zone of the Ecological and Natural Map of Korea that were obtained through 202 field surveys over six years. Five endangered mammal species were identified including otters, long-tailed gorals, martens, leopard cats, and flying squirrels. The total number of habitat traces collected was 918, of which 897 traces (97.7%) were excrement types. The total surveyed distance was 697.7 km and there were 2,184 grids of 250×250 m each. Of these grids, 441 or 20.2% were confirmed as habitats of endangered mammals. Moreover, we analyzed results of repeated surveys in the same area by converting them into individual one-time surveys, accounting for 23.1% of the total area. The flying squirrel showed a low correlation with the frequency of field surveys but showed many habitats in a specific season. Leopard cats and martens were correlated with the frequency of field surveys. Results of analysis confirm that the grid method used for establishing the Ecological and Natural Map is unsuitable for the habitat division of flying squirrels, otters, leopard cats, and martens, and it does not reflect the actual habitats of these four species. Therefore, we propose that the concept of the habitat grid of species must be reevaluated and improved, specifically for endangered mammals.

An Empirical Inquiry into Psychological Heuristics in the Context of the Korean Distribution Industry within the Stock Market

  • Jeong-Hwan LEE;Se-Jun LEE;Sam-Ho SON
    • Journal of Distribution Science
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    • v.21 no.9
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    • pp.103-114
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    • 2023
  • Purpose: This paper aims to assess psychological heuristics' effectiveness on cumulative returns after significant stock price changes. Specifically, it compares availability and anchoring heuristics' empirical validity due to conflicting stock return predictions. Research Design, Data, and Methodology: This paper analyzes stock price changes of Korean distribution industry stocks in the KOSPI market from January 2004 to July 2022, where daily fluctuations exceed 10%. It evaluates availability heuristics using daily KOSPI index changes and tests anchoring heuristics using 52-week high and low stock prices as reference points. Results: As a result of the empirical analysis, stock price reversals did not consistently appear alongside changes in the daily KOSPI index. By contrast, stock price drifts consistently appeared around the 52-week highest stock price and 52-week lowest stock price. The result of the multiple regression analysis which controlled for both company-specific and event-specific variables supported the anchoring heuristics. Conclusions: For stocks related to the Korean distribution industry in the KOSPI market, the anchoring heuristics theory provides a consistent explanation for stock returns after large-scale stock price fluctuations that initially appear to be random movements.

The Effect of Water-Filtered Infrared-A (wIRA) on Body Core and Body Surface Temperatures in Anesthetized Rabbits Maintained with Isoflurane

  • Geonho Choi;Dongseok Kim;Eungmo Tae;Ilgwon Jung;Sang-Kwon Lee;Won-Jae Lee;Sung-Ho Yun;Young-Sam Kwon;Min Jang
    • Journal of Veterinary Clinics
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    • v.40 no.1
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    • pp.44-49
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    • 2023
  • The purpose of this study was to evaluate body temperature changes in rabbits anesthetized using water-filtered infrared-A (wIRA). Ten rabbits were used for this study. For the experimental group (wIRA group; wG, n = 5), the experimental equipment was used and irradiated using wIRA. The control group (CG, n = 5) did not have any warming device. There were no significant differences in heart rate, respiration rate, and end tidal CO2 (EtCO2) between wG and CG. After 80 min, the core body temperature of wG rabbits was significantly higher than that of CG rabbits. The surface body temperature was significantly higher while receiving wIRA support at all time points after 5 min. In conclusion, in rabbits under inhalation anesthesia, the surface body temperature was better maintained than the core body temperature when using wIRA.

A Study on the Prediction of Stock Return in Korea's Distribution Industry Using the VKOSPI Index

  • Jeong-Hwan LEE;Gun-Hee LEE;Sam-Ho SON
    • Journal of Distribution Science
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    • v.21 no.5
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    • pp.101-111
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    • 2023
  • Purpose: The purpose of this paper is to examine the effect of the VKOSPI index on short-term stock returns after a large-scale stock price shock of individual stocks of firms in the distribution industry in Korea. Research design, data, and methodology: This study investigates the effect of the change of the VKOSPI index or investor mood on abnormal returns after the event date from January 2004 to July 2022. The significance of the abnormal return, which is obtained by subtracting the rate of return estimated by the market model from the rate of actual return on each trading day after the event date, is determined based on T-test and multifactor regression analysis. Results: In Korea's distribution industry, the simultaneous occurrence of a bad investor mood and a large stock price decline, leads to stock price reversals. Conversely, the simultaneous occurrence of a good investor mood and a large-scale stock price rise leads to stock price drifts. We found that the VKOSPI index has strong explanatory power for these reversals and drifts even after considering both company-specific and event-specific factors. Conclusions: In Korea's distribution industry-related stock market, investors show an asymmetrical behavioral characteristic of overreacting to negative moods and underreacting to positive moods.

A case report of an unusual temporomandibular joint mass: Nodular fasciitis

  • Han-Sol Lee;Kyu-Young Oh;Ju-Hee Kang;Jo-Eun Kim;Kyung-Hoe Huh;Won-Jin Yi;Min-Suk Heo;Sam-Sun Lee
    • Imaging Science in Dentistry
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    • v.53 no.1
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    • pp.83-89
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    • 2023
  • Nodular fasciitis (NF) is a benign myofibroblastic proliferation that grows very rapidly, mimicking a sarcoma on imaging. It is treated by local excision, and recurrence has been reported in only a few cases, even when excised incompletely. The most prevalent diagnoses of temporomandibular joint(TMJ) masses include synovial chondromatosis, pigmented villonodular synovitis, and sarcomas. Cases of NF in the TMJ are extremely rare, and only 3 cases have been reported to date. Due to its destructive features and rarity, NF has often been misdiagnosed as a more aggressive lesion, which could expose patients to unnecessary and invasive treatment approaches beyond repair. This report presents a case of NF in the TMJ, focusing on various imaging features, along with a literature review aiming to determine the hallmark features of NF in the TMJ and highlight the diagnostic challenges.

A Study of the Microstructure Properties and Mechanical/electrochemical Behavior of Ti Alloy for Fastening (체결용 Ti 합금의 미세조직 특성 및 기계적/전기화학적 거동 분석 연구)

  • Lee, H.J.;Anaman, Sam Yaw;Choi, J.M.;Lee, K.H.;Park, L.J.;Cho, H.H.
    • Transactions of Materials Processing
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    • v.31 no.3
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    • pp.151-159
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    • 2022
  • Ti alloys are used in a wide range of applications, especially for aviation and medical purposes, because of their high specific strength and excellent corrosion properties. When subjected to various manufacturing processes, one of the most popular Ti alloys, Ti-6Al-4V, exhibits a variety of microstructural and mechanical properties that makes it an attractive lightweight metal. The purpose of this study was to analyze the microstructure and mechanical properties of Ti alloy wires. Subsequently, the microstructure and electrochemical behavior of Ti alloy bolts produced from these wires were analyzed. The Ti alloy wires are manufactured with different diameters (6.22, 7.81 mm alloys), and their microstructures are measured using electron backscatter diffraction. Recrystallization was observed to occur significantly in the 7.81 alloy than in the 6.81 alloy, and the strain distribution of 7.81 alloy is seen to be likely more uniform than 6.22 alloy. Ti alloy bolt was then forged under moderate temperature by using the 7.81 alloy. Results of the electrochemical analysis indicate that the Ti alloy bolt has excellent corrosion resistance.

Multifunctional Marine Exploration Robot for Fish Farm Management (양식장 관리를 위한 다기능 해양탐사 로봇)

  • Yeo, Sang-Sam;Park, Joo-Ryeoll;Lee, Dong-Kyu;Kim, Myeong-Gi;Yu, Ju-Young;Lee, Sang Hyeop
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2021.07a
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    • pp.489-490
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    • 2021
  • 본 연구에서는 해양사고 처리 중 발생하는 인명사고 발생률을 감소시키고, 효율적으로 양식장을 관리하는 것을 전제로 카메라와 센서를 다기능 해양탐사 로봇에 적용하고자 한다. 현재의 양식장 관리 시스템은 수온 체크만 할 수 있게 되어있다. 이러한 시스템은 양식어에게 적합한 환경을 제공해주기 쉽지 않다. 본 논문은 이러한 문제점들을 개선하기 위해 기존의 해양 처리시스템과 양식 시스템 대신 카메라와 수온 센서, pH 농도 센서, 초음파 거리 센서, DC 모터, 블루투스 모듈을 적용한 다기능 해양탐사 로봇 기술을 제안한다. 기존의 시스템과는 다르게 안전하고 효율적으로 환경을 분석하고, 제어할 수 있다.

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A Study for Recent major Cyber incidents and preventive measures (최근 주요 침해사고 유형과 예방 대책)

  • Jung, Ye-bin;Ha, Seong-hyeon;Lee, Se-Ho;Choi, Sang-Yong;Kim, Jeung-Sam;Lee, Jong-Rak
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2020.07a
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    • pp.99-102
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    • 2020
  • 인터넷 사용 인구가 증가하면서 이제 사이버공간은 우리 생활에서 중요한 인프라가 되었다. 최근 인터넷 침해사고의 추세는 주로 금전적인 이익을 얻기 위하여 발생하고 있으며, 그 수법이 갈수록 지능적이고 복합적인 기법들을 사용하여 대응과 분석이 점점 어려워지고 있다. 인터넷 침해사고는 이제 특정 개인, 기업의 문제가 아닌 사회적, 국가적 이슈가 되고 있다. 이처럼 인터넷 등 정보통신의 발달에 따른 생활의 편리함 등 순기능과 함께 해킹 등과 같은 역기능도 피할 수 없는 상황이다. 침해사고에 대한 대응은 특정 계급에 국한되는 것이 아니라 사이버공간을 이용하든 모든 사용자가 대비를 해야한다. 사이버 위협에 지속적으로 대비하고, 침해사고 예방 및 대응 수준과 사용자들의 보안 인식을 높혀 개인, 기업, 국가의 안전을 보장해야 할 것이다. 이에 본 연구에서는 침해사고 사례를 바탕으로 분석해 개인 인터넷 이용자들에게 인터넷 침해사고 예방 및 대응요령을 제공한다.

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Optimization of Aerosolizable Messenger RNA Lipid Nanoparticles for Pulmonary Delivery

  • Se-Hee Lee;Jong Sam Lee;Dong-Eun Kim;Keun-Sik Kim
    • Biomedical Science Letters
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    • v.29 no.4
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    • pp.231-241
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    • 2023
  • Messenger RNA (mRNA)-based vaccines and treatments have recently emerged as a promising strategy. Naked mRNA presents various limitations for direct delivery. Therefore, in this paper, Lipid Nanoparticles (LNPs) were utilized for the delivery of mRNA. Lipid nanoparticle (LNP) mRNA systems are highly effective as vaccines, but their efficacy for pulmonary delivery has not yet been fully established. Additionally, research on effective delivery systems and administration methods for vaccines is required to resolve the stability and degradation issues associated with naked mRNA delivery. This study aimed to determine mRNA delivery efficiency via the inhalation of a lipid nanoparticle (LNP) formulation designed specifically for pulmonary delivery. To this purpose, we built a library of seven LNP configurations with different lipid molar and N/P ratios and evaluated their encapsulation efficiency using gel retardation assay. Among the tested LNPs, LNP1, LNP2-2, and LNP3-2 demonstrated high transfection efficiency in vitro based on FACS analyses luciferase assays, and intracellular accumulation tests. The mRNA delivery efficiencies of the selected LNPs after inhalation and intravenous injection were compared and evaluated. LNP2-2 showed the highest mRNA expression in healthy mouse lungs when aerosolized and was found to be non-toxic. These results indicate that LNP2-2 is a promising carrier for lung mRNA delivery via inhalation.

Solitary fibrous tumor in the temporalis muscle: a case report and literature review

  • Jun Ho Choi;Soo Hyuk Lee;Jae Ha Hwang;Kwang Seog Kim;Sam Yong Lee
    • Archives of Craniofacial Surgery
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    • v.24 no.5
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    • pp.230-235
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    • 2023
  • Solitary fibrous tumor (SFT) is an infrequently occurring neoplasm most commonly observed in the pleura, but it can develop in the head and neck region in occasional cases. However, no reports have described SFT in the temporalis muscle. Herein, we present the first known case of SFT in the temporalis muscle. A 47-year-old man complained of a painless palpable mass on his right temple. Facial enhanced computed tomography identified a 4.0×2.9×1.4 cm mass presenting as a vascular tumor in the right temporalis muscle under the zygomatic arch. The mass was excised from the right temporalis muscle under general anesthesia. A histopathologic examination revealed that the mass was an SFT. No complications occurred after surgery, including functional disability or sensory loss. The patient was followed up for 3 months without complications. Although SFT in extrapulmonary regions is rare, it should be considered in the differential diagnosis of masses that occur in the temporal area.