• Title/Summary/Keyword: Sangwon

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Analysis of Main Factors in aids to Navigation Accidents using a Bayesian Network (베이지안 네트워크를 이용한 항로표지사고 주요 요인 분석)

  • Sangwon Park;Youngsoo Park;Beom-Sik Moon
    • Journal of Navigation and Port Research
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    • v.47 no.6
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    • pp.324-330
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    • 2023
  • Aids to navigation, which provide information about a ship's position, direction, and the location of obstacles, are crucial for uninterrupted maritime services. This study aimed to analyze accidents involving aids to navigation that resulted in service disruptions and identify the key factors associated with these accidents. Aids to navigation accident data from 2000 to 2022 were utilized to achieve this. We categorized accidents by accident type, cause, region, season, and type of navigation aid and established a network through correlation analysis. Bayesian networks based on aids to navigation accidents were assigned prior probabilities, and the factors that increased the probability of accidents for different types of aids to navigation were identified. The findings can be used to infer the causes of unreported aids to navigation accidents and serve as foundational data for the prevention of such accidents.

The Diagnostic Performance of the Length of Tumor Capsular Contact on MRI for Detecting Prostate Cancer Extraprostatic Extension: A Systematic Review and Meta-Analysis

  • Tae-Hyung Kim;Sungmin Woo;Sangwon Han;Chong Hyun Suh;Soleen Ghafoor;Hedvig Hricak;Hebert Alberto Vargas
    • Korean Journal of Radiology
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    • v.21 no.6
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    • pp.684-694
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    • 2020
  • Objective: The purpose was to review the diagnostic performance of the length of tumor capsular contact (LCC) on magnetic resonance imaging (MRI) for detecting prostate cancer extraprostatic extension (EPE). Materials and Methods: PubMed and EMBASE databases were searched up to March 24, 2019. We included diagnostic accuracy studies that evaluated LCC on MRI for EPE detection using radical prostatectomy specimen histopathology as the reference standard. Quality of studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Sensitivity and specificity were pooled and graphically presented using hierarchical summary receiver operating characteristic (HSROC) plots. Meta-regression and subgroup analyses were conducted to explore heterogeneity. Results: Thirteen articles with 2136 patients were included. Study quality was generally good. Summary sensitivity and specificity were 0.79 (95% confidence interval [CI] 0.73-0.83) and 0.67 (95% CI 0.60-0.74), respectively. Area under the HSROC was 0.81 (95% CI 0.77-0.84). Substantial heterogeneity was present among the included studies according to Cochran's Q-test (p < 0.01) and Higgins I2 (62% and 86% for sensitivity and specificity, respectively). In terms of heterogeneity, measurement method (curvilinear vs. linear), prevalence of Gleason score ≥ 7, MRI readers' experience, and endorectal coils were significant factors (p ≤ 0.01), whereas method to determine the LCC threshold, cutoff value, magnet strength, and publication year were not (p = 0.14-0.93). Diagnostic test accuracy estimates were comparable across all assessed MRI sequences. Conclusion: Greater LCC on MRI is associated with a higher probability of prostate cancer EPE. Due to heterogeneity among the studies, further investigation is needed to establish the optimal cutoff value for each clinical setting.

Preparation and Characterization of poly(ethylene-co-vinyl acetate)/Magnesium Hydroxide Composites by Electron Beam Crosslinking (전자빔 가교에 의한 폴리(에틸렌-co-초산 비닐)/수산화 마그네슘 복합재료의 제조 및 평가)

  • Si-Hyeong Lee;Byoung-Min Lee;Hyun-Rae Kim;Sangwon Park;Jong-Seok Park;Yong Seok Kim;Sungmin Park;Jae-Hak Choi
    • Journal of Radiation Industry
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    • v.17 no.3
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    • pp.225-232
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    • 2023
  • In this study, poly(ethylene-co-vinyl acetate)/magnesium hydroxide (EVA/MDH) composites were prepared by electron beam crosslinking. EVA as a matrix resin and MDH as a flame retardant were melt-blended and compression molded to prepare EVA/MDH composites. The prepared EVA/MDH composites were electron beam-irradiated at various absorbed doses of 50~200kGy. The effects of electron beam irradiation on the gel content, tensile strength, elongation-at-break, thermal properties, and flame retardancy of the composites were investigated. The gel content and tensile strength increased, while the elongation-at-break decreased with an increase in the absorbed dose due to the formation of crosslinked network structures. In addition, the thermal stability and flame retardancy improved as the absorbed dose increased. Therefore, the EVA/MDH composites prepared in this study can be used as an insulation material for flame-retardant and heat-resistant wires and cables.

Temperature Dependence of Tensile Properties in Single Crystal Superalloy CMSX-4 (단결정 초내열 합금 CMSX-4의 온도에 따른 인장특성의 변화)

  • Baig-Gyu Choi;Jeonghyeon Do;Joong Eun Jung;Sangwon Lee;In Soo Kim
    • Journal of Korea Foundry Society
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    • v.44 no.3
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    • pp.59-69
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    • 2024
  • The tensile properties of the single crystal superalloy CMSX-4 were examined at various temperatures. In the heat-treated state, some portion of the eutectic γ-γ' remained, and a uniform cuboidal γ' particles existed across the entire material. The yield strength and tensile strength reached highest at 750℃ and decreased with raising testing temperature. The elongation was lowest at 650℃ due t℃oncentrated deformation near the fracture area. However, the elongation increased at higher temperatures due to uniform deformation throughout the entire specimen. Fracture surface analysis tested at 850℃ and 950℃ revealed that cracks originated from casting defects. TEM observations conducted after the tensile test indicated that the primary deformation mechanism at room temperature involved dislocation shearing within the γ' phase. However, the increased strength both at 750℃ where stacking faults generated and at 650℃ was caused by the increased resistance of γ' phase to dislocation. The strength decreased because the movement of dislocations became easier due to the thermal activation process at and above 850℃.

The Origin of Changseung and Ongjung Stone (장승의 기원과 옹중석)

  • Chung, Seung Mo
    • Korean Journal of Heritage: History & Science
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    • v.46 no.1
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    • pp.160-175
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    • 2013
  • There is the need to make a sharp distinction as regards JANGSEUNGs (Korean traditional totem poles) that are different in origin, history and function. This study is to identify the functions of the figures, as well as to trace stone JANGSEUNGs to their origins. In this regard, researched were conducted into the origins of JANGSEUNGs and their changes in history. There was a tradition in the GORYEO Dynasty (an ancient dynasty in the Korean Peninsula) that it erected JANGSAENGs (the archaic name of JANGSEUNGs) or allied stone figures within temples; especially, 'TONGDOSA GUKJANGSAENG SEOKPYO (a stone JANGSAENG that was erected by the royal command and is at the entrance of TONGDO Temple located in YANGSAN, South GYEONGSANG Province, South Korea)' functions as a stone monument rather than as a stone sign. In the engraved inscription, it is written that it should be erected in the form of PANA as before. 'PANA' refers to 'ZHONGKUI', a god in Chinese Taoism believed to exorcise devils that spread diseases. The inscription is to define the territory of TONGDO Temple. The article on HAN JUN GYEOM in a book 'WORAKGI (a travelogue on WORAK Mountain in North CHUNGCHEONG Province, South Korea)' written by HEO MOK makes it possible to guess the scale of GUKJANGSAENGs erected in DOGAP Temple. The stones, on which 'GUKJANGSAENG' or 'HWANGJANGSAENG' were engraved, are not JANGSAENGs but are demarcation posts. In the JOSEON Dynasty (the last dynasty in the Korean Peninsula) JANGSAENGs functioned as signposts. Unlike JANGSAENGs in temples, they were made of wood. At first, the word 'JANGSAENG' was written '長生' in Chinese characters, but in the JOSEON Dynasty another character '木 (wood)' was added to them, and thus the orthography was likely to change into 'JANGSEUNG.' In the JOSEON Dynasty, in addition, optative or geomantic figures were not called 'JANGSEUNG.' Historically, for instance, there has been no case where 'DOL HARBANGs (stone figures found only in JEJU ISLAND, South Korea)' are called 'JANGSEUNG.' In a book 'TAMRA GINYEON (a historical record on JEJU Island, South Korea)' it is written that KIM MONG GYU, JEJU governor, erected ONGJUNG Stones outside the fortress gate. ONGJUNG Stones usually refer to stone statues erected in front of ancient kings or dignitaries' mausoleums. Moreover, they were geomantic figures erected to suppress miasma. A magazine 'GWANGJUEUPJI (a journal on old GWANGJU, South Korea, 1899)' shows that two two ONGJUNG Stones were so erected that they might look at each other to suppress miasma from a pathway through which lucks lose. On the two stone figures located in BUAN-EUP, North JEOLLA Province, South Korea, inscriptions 'SANGWON JUJANGGUN' and 'HAWON DANGJANGGUN' were engraved. The words are to identify the figures' sexes. They are a kind of optative geomantic figures, and therefore there is no reason to call them 'JANGSAENG' or 'JANGSEUNG' or 'DANGSAN.' The words 'SANGWON' and 'HAWON' are closely associated with Taoism. Since then, the words have been widely used as inscriptions on stone figures in temples, and subsequently are used for JANGSEUNGs. A hatted ONGJUNG Stone, found in BUKANSAN Fortress, disappeared and other ones may be being buried somewhere. Meanwhile, ONGJUNG Stones in JEJU Island and stone figures in BUAN-EUP have hardly been displaced and thus have properly functioned. Stone figures, made in those days, seem to be most similar in function to JANGSAENGs made during the GORYEO Dynasty. Specifically, like earlier JANGSAENGs, stone figures made during the early to mid-18th century were likely to function not only as optative figures but as boundary stones. Most of stone figures in temples were made whenever the land use survey was conducted throughout the nation, but given that at the same period of time, the commonalty filed many lawsuits against grave sites, temples might erect many stone figures to mark their territories. Currently, wooden or stone figures are commonly called 'JANGSEUNG', but they were erected in different epochs and for different reasons. Their origins are to be sought in stone figures that functioned not only as optative figures in temples but as boundary stones during the GORYEO Dynasty.

A Review on Microbialites: a Korean Perspective (미생물암에 대하여: 한국적 관점)

  • Lee, Jeong-Hyun
    • The Journal of the Petrological Society of Korea
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    • v.24 no.4
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    • pp.291-305
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    • 2015
  • Microbialites are defined as rocks formed by microbial organisms. After their first appearance around 3.5 billion years ago, microbialites occur in various depositional environments throughout geological periods. Microbial organisms form microbialites by trapping and binding detrital sediments and/or precipitating carbonate cements, resulting in formation of various microstructures and mesostructures. Four major types of microbialites are distinguished based on their mesostructures: stromatolite, thrombolite, dendrolite, and leiolite. In the geological records, occurrences of microbialites are influenced by calcium carbonate saturation of seawater and interaction of microbialites with metazoans. Stromatolites mainly flourished during the Precambrian, and diminished as level of atmospheric carbon dioxide declined. On the other hand, thrombolites, mainly formed by calcified microbes, began to flourish from the Neoproterozoic. As metazoans diversified in the Phanerozoic, proportion of the microbialites within sedimentary record declined. Since then, microbialites only occasionally flourished during the Phanerozoic, such as shortly after mass-extinction events. In the Korean Peninsula, microbialites occur in the Neoproterozoic Sangwon System, the Early Paleozoic Joseon Supergroup, and the Cretaceous Gyeongsang Supergroup, which form different shapes according to their age and depositional environments. By performing detailed studies on these Korean microbialites, it is possible to understand how microbes affected geological records and sedimentary environments, as well as their interaction with other organisms.

Design and Performance Analysis of an Off-Axis Three-Mirror Telescope for Remote Sensing of Coastal Water (연안 원격탐사를 위한 비축 삼반사경 설계와 성능 분석)

  • Oh, Eunsong;Kang, Hyukmo;Hyun, Sangwon;Kim, Geon-Hee;Park, YoungJe;Choi, Jong-Kuk;Kim, Sug-Whan
    • Korean Journal of Optics and Photonics
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    • v.26 no.3
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    • pp.155-161
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    • 2015
  • We report the design and performance analysis of an off-axis three-mirror telescope as the fore optics for a new hyperspectral sensor aboard a small unmanned aerial vehicle (UAV), for low-altitude coastal remote sensing. The sensor needs to have at least 4 cm of spatial resolution at an operating altitude of 500 m, $4^{\circ}$ field of view (FOV), and a signal to noise ratio (SNR) of 100 at 660 nm. For these performance requirements, the sensor's optical design has an entrance pupil diameter of 70 mm and an F-ratio of 5.0. The fore optics is a three-mirror system, including aspheric primary and secondary mirrors. The optical performance is expected to reach $1/15{\lambda}$ in RMS wavefront error and 0.75 in MTF value at 660 nm. Considering the manufacturing and assembling phase, we determined the alignment compensation due to the tertiary mirror from the sensitivity, and derived the tilt-tolerance range to be 0.17 mrad. The off-axis three-mirror telescope, which has better performance than the fore optics of other hyperspectral sensors and is fitted for a small UAV, will contribute to ocean remote-sensing research.

The Revised Korean Practice Parameter for the Treatment of Attention-Deficit Hyperactivity Disorder (II) - Diagnosis and Assessment - (주의력결핍 과잉행동장애 한국형 치료 권고안 개정안(II) - 진단 및 평가 -)

  • Lee, Moon-Soo;Park, Su-Bin;Kim, Gyung-Mee;Kim, Hyun-Jin;Park, Sangwon;Kim, Yunsin;Lee, Young Sik;Kweon, Yong-sil;Shin, Dongwon
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.28 no.2
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    • pp.58-69
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    • 2017
  • Attention-deficit hyperactivity disorder (ADHD) is a highly prevalent, impairing, and comorbid disorder that persists into adulthood. ADHD should be diagnosed in the same manner as other common adult mental health disorders. The three most important components in the comprehensive evaluation of patients with ADHD are the clinical interview, medical examination, and completion and scoring of behavior rating scales. The diagnostic evaluation of ADHD should include questions about the symptoms, family history, prior evaluation and treatment of ADHD, as well as other problems including alcohol and drug use. Screening interviews or rating scales, as well as interviews, should be used. When it is feasible, clinicians may wish to supplement these components of the evaluation with the objective assessments of the ADHD symptoms, such as through psychological tests. These tests are not essential to reaching a diagnosis, however, or to treatment planning, but may yield further information about the presence and severity of cognitive impairments that could be associated with some cases of ADHD. As comorbidity is the rule rather than the exception, clinicians should carefully screen for comorbid disorders as part of a comprehensive assessment of ADHD. To receive a diagnosis of ADHD, the person must be experiencing significant distress or impairment in his or her daily functioning, and must not meet the criteria for other mental disorders which might better account for the observed symptoms, such as mental retardation, autism or other pervasive developmental disorders, mood disorders and anxiety disorders. This report aims to suggest practice guidelines for the assessment and diagnosis of children, adolescents and adults with ADHD in Korea.

Evaluation of Capability for Practicing CM at Risk in Korea (국내 시공책임형 건설사업관리 수행을 위한 기업 역량 평가)

  • Ryu, HanGuk;Lee, Sangwon;Choi, Jaehyun
    • Korean Journal of Construction Engineering and Management
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    • v.21 no.2
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    • pp.79-87
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    • 2020
  • The Korean domestic construction management at risk (CMAR) market is in the process of completing the pilot project execution under the leadership of the Ministry of Land, Infrastructure and Transport as of December 2019. The government starts practicing CMAR an alternative delivery method widely in order to diversify delivery methods and enhance construction technology. The CMAR market is thus expected to grow. This study was conducted to improve CMAR firms' capability by developing self-assessment tools for them to evaluate current capability more effectively. As a result of defining standard core capability and additional elements categorized by project execution phase and management area, and performing evaluation from the CMAR project participants, it was found that the general project management capability in the pre-design and procurement phase and quality management area was lower compared to the construction phase and other areas. In addition, the capability of cost management area was lower in spite of its high importance. Communication and coordination, process optimization, and target values achievement were at the initial level of capability and continuous improvement was required.

Dual infections of Tomato mosaic virus (ToMV) and Tomato yellow leaf curl virus (TYLCV), or Tomato mosaic virus (ToMV) and Tomato chlorosis virus (ToCV), detected in tomato fields located in Chungcheongnam-do in 2017

  • Choi, Go-Woon;Kim, Boram;Ju, Hyekyoung;Cho, Sangwon;Seo, Eunyoung;Kim, Jungkyu;Park, Jongseok;Hammond, John;Lim, Hyoun-Sub
    • Korean Journal of Agricultural Science
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    • v.45 no.1
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    • pp.38-42
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    • 2018
  • Demand for tomatoes has been increasing every year as people desire more healthy food. In Korea, tomatoes are mainly grown in the Chungnam, Chunnam and Kyungnam provinces. Recently, reports of whitefly-transmitted viral diseases have increased due to newly emerging whitefly pressures caused by climate change in Korea. Specifically, in 2017, the main tomato growing areas, Buyeo and Nonsan in Chungnam, showed damage typical of viral infection; therefore, we investigated viral diseases in these areas. We collected samples with virus-like symptoms and found that not only whitefly transmitted Tomato yellow leaf curl virus (TYLCV) and Tomato chlorosis virus (ToCV) were detected but also Tomato mosaic virus (ToMV, for which no specific vector is known) and Tomato spotted wilt virus (TSWV, transmitted by thrips). The ToMV-infected samples were mostly co-infected with either TYLCV or ToCV. Mixed infections of different combinations of TYLCV, ToCV and ToMV were detected with the mixed infection of two whitefly-transmitted viruses (TYLCV and ToCV) causing the most severe symptoms. According to the CP sequence of each virus, the 100% identities were shown to be Mexico/ABG73017.1 (TYLCV), Greece/CDG34553.1 (ToCV), China/AKN79752 (TSWV), and Australia/NP078449.1 (ToMV). Based on the sequence data, we presumed that these tomato infecting viruses were transmitted through insects and seeds introduced from neighboring countries.