• 한국건설관리학회논문집
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• 제15권5호
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• pp.22-30
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• 2014

본 논문은 시기별 국내 건설경기 변화와 해외건설수주 간의 관계성을 벡터오차수정모형을 통해 비교분석하는 것을 목적으로 한다. 분석결과 IMF 외환위기 이후에는 주거용 건설경기가 하락할 경우에만, 해외건설시장 진출이 더욱 활발히 나타나는 것으로 확인되었다. 게다가 IMF 외환이기 이전보다 외환위기 이후에는 국내 주거용 건설경기 변화에 즉각적으로 반응하여 해외건설시장 진출 규모가 확대되는 것으로 나타났다. 이와 같은 현상은 국내 건설업체들의 사업 포트폴리오 상 주거용 건설경기에 매우 민감하게 반응할 수밖에 없음에 기인한다. 즉 국내 주택시장 침체는 국내 건설업체의 경영상태에 심각한 영향을 미치게 되고, 이를 긴급히 타개하기 위하여 해외건설시장 진출 규모를 확대한 것으로 판단된다. 본 연구에서 분석을 통해 확인한 바와 같이 주택경기 침체에 따른 건설업체 경영상태 악화를 개선하기 위하여 해외건설시장 진출의 외연적확대는 오히려 건설업체 경영상태를 더욱더 악화시키는 결과를 초래한 것이다. 이에 따라 급박한 상황에서의 사업 전환은 오히려 수익률 확보보다 회사 내 현금흐름 확보를 위한 수단으로 전락할 수도 있기 때문에 전략적 유연성을 확보할 수 있도록 사업 다각화 수준을 지속적으로 일정 범위 안에서 관리할 필요가 있을 것으로 판단된다.

• 인지과학
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• 제22권4호
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• pp.365-384
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• 2011

변화탐지 과제를 사용한 최근의 시각작업기억 연구는 기억된 표상을 감각적 표상과 대조하는 비교처리 과정이 상대적으로 신속하게 수행될 가능성을 보고하였다[1]. 이러한 가설을 검증하기 위해, 본 연구에서는 기억항목에 대한 공고한 표상 형성이 요구되는 시점 또는 기억항목과 검사항목에 대한 비교 처리가 요구되는 시점에 역행패턴차폐 자극을 제시하여 두 처리 과정에서의 차폐 간섭 효과의 발현 유무를 비교하였다. 실험 1에서는 네 개의 기억항목 또는 검사항목의 제시에 뒤이어 64ms 또는 150ms의 차폐출현간격을 두고 차폐자극이 제시되었으며 피험자는 기억과 검사항목 간 차이 유무를 보고하는 변화탐지 과제를 수행하였다. 실험 결과, 기억항목에 뒤이어 차폐가 제시된 경우(기억차폐 시행)에는 차폐출현간격에 관계없이 변화탐지 정확도가 저조했으나 검사항목에 뒤이어 차폐가 제시된 경우(검사차폐시행)에는 차폐출현간격 64ms 조건에 비해 150ms 조건에서 변화탐지 정확도가 상대적으로 높았다. 실험 2에서는 항목의 개수를 변화시키고(1, 2, 3, 4개) 차폐출현간격을 세분화(117ms, 234ms, 350ms, 584ms)시켜 항목 개수의 증가와 차폐출현간격의 감소에 따른 간섭 효과의 증감패턴을 조사하였다. 기억차폐시행에서는 항목의 개수가 늘어나고 차폐출현간격이 짧아 질수록 점차 증가하는 간섭패턴이 관찰되었으나, 검사차폐시행에서는 이러한 패턴이 상대적으로 미미하였다. 이러한 결과는 시각작업기억의 비교처리과정이 공고화 과정에 비해 상대적으로 신속하고 정확하게 수행된다는 기존 연구의 제안을 지지한다.

• 한국지리정보학회지
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• 제9권3호
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• pp.183-192
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• 2006

최근 우리나라는 지형적, 지리적 조건에 따른 홍수뿐만 아니라 기상이변에 의한 홍수의 발생빈도가 높아 점차 그 피해가 늘어나고 있다. 홍수의 피해는 대규모로 발생하므로 홍수가능지역을 사전에 예측하여 홍수에 의한 피해를 예방할 필요가 있다. 이에 본 연구에서는 홍수기록이 부족한 대규모의 넓은 지역에 대해 홍수가능지역을 예측할 목적으로 DEM과 홍수위를 이용하는 지형학적 방법과 수리모형을 이용하는 수리학적 방법을 사용하여 홍수에 의한 범람가능지역을 예측하였다. 연구대상지역은 과거 홍수에 피해가 가장 컸던 경기도 문산천 유역을 선정하였고, 지형학적 방법과 수리학적 방법을 이용하여 홍수지역을 예측한 결과를 비교 검토하였다. 본 연구의 결과, GIS를 이용하면 광의의 지역에 대해서 개략적인 홍수가능지역을 예측할 수 있었고, 수리모형을 이용하면 정밀하고 정확한 예측이 가능하였다. 위의 두가지 방법을 병행하면 전국 재해지도를 작성할 수 있을 것으로 판단되며, 재해위험에 대한 사전정보를 제공하여 재해에 대비함으로서 피해를 줄일 수 있을 것으로 판단된다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권3호
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• pp.202-207
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• 2016

Purpose: The purpose of this study is main factors (environmental conditions, pattern spacing, pattern material) that effect the ion-migration of PCB. Methods: Recently, the electronic components are becoming more high density of electronic device, so that electronic circuits have smaller pitches between the patten and more vulnerable to insulation failure. so the reliability of electric insulation of device has become an ever important issue as device contact pitches of pattern. Usually, ion-migration occurs in high temperature and high humidity environment as voltage is applied to the circuit. Under high temperature and high humidity, voltage applied electronic components respond to applied voltages by metals's electrochemical ionization and a conducting filament forms between the anode and cathode across a nonmetallic medium. This leads to short-circuit failure of the electronic component. Results: we studied ion-migration that occurs in accordance with the main factors (environmental conditions, pitches, pattern material). The PCB pattern material was made by two different types of material (free solder, OSP) for this research and pitches of pattern is 0.15mm, 0.3mm, 0.5mm. PCB was experimented in the environmental conditions (high temperature $120^{\circ}C$, high temperature and high humidity $85^{\circ}C$, 85%RH) and was analyzed for ion-migration through the experiment results. Conclusion: We confirmed that environmental condition, pitches of pattern, pattern material had effect on ion-migration of PCB.

• 한국농공학회논문집
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• 제60권4호
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• pp.105-111
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• 2018

Institutional inertia anti-disaster standard was presented mainly on the upper surface, it is necessary to improve to the soil type standard and uplift the resistance standard greenhouse that are vulnerable to strong winds. In this study, we carried out a field test using the load control method in order to evaluate the uplift resistance of continuous foundation of greenhouse with different depths of the rafters. Institutional inertia anti-disaster standard of greenhouse foundation did not protect the greenhouse structure from the damages caused by strong winds and heavy snow. Therefore, field tests for behavior characteristics of continuous greenhouse foundation were carried out to ensure stable facility cultivation. The field test condition was evaluated using different embedded depth as follows: 30cm, 40cm, 50cm and spacing 50cm, 60cm, 70 cm. As a result of the uplift resistance field tests using the load control method, the minimum uplift resistance was found to be over 90kg and uplift resistance displacement was 9.4mm. Uplift resistance of the continuous greenhouse foundation was in the range of 90-180 kg according to embedded depth and spacing. Using the test condition, there was no constant trend in the uplift resistance.

• The Journal of Korean Physical Therapy
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• 제15권1호
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• pp.155-170
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• 2003

Lumbar segmental instability is considered to represent a significant sub-group within the chronic low back pain population. This condition has a unique clinical presentation that displays its symptoms and movement dysfunction within the neutral zone of the motion segment. The loosening of the motion segment secondary to injury and associated dysfunction of the local muscle system renders it biomechanically vulnerable in the neutral zone. There in evidence of muscle dysfunction related to the control of the movement system. There is a clear link between reduced proprioceptive input, altered slow motor unit recruitment and the development of chronic pain states. Dysfunction in the global and local muscle systems in presented to support the development of a system of classification of muscle function and development of dysfunction related to musculoskeletal pain. The global muscles control range of movement and alignment, and evidence of dysfunction is presented in terms of imbalance in recruitment and length between the global stability muscles and the global mobility muscles. The local stability muscles demonstrate evidence of failure of aeequate segmental control in terms of allowing excessive uncontrolled translation or specific loss of cross-sectional area at the site of pathology Motor recruitment deficits present as altered timing and patterns of recruitment. The evidence of local and global dysfunction allows the development of an integrated model of movement dysfunction. The clinical diagnosis of this chronic low back pain condition is based on the report of pain and the observation of movement dysfunction within the neutral zone and the associated finding of excessive intervertebral motion at the symptomatic level. Four different clinical patterns are described based on the directional nature of the injury and the manifestation of the patient's symptoms and motor dysfunction. A specific stabilizing exercise intervention based on a motor learning model in proposed and evidence for the efficacy of the approach provided.

• 농업생명과학연구
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• 제44권5호
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• pp.15-22
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• 2010

울릉도 자생 우산고로쇠나무군락의 합리적인 관리를 위한 기초정보를 제공하기 위하여 식생구조와 토양환경을 분석하였다. 층위별 중요치는 상층에서는 우산고로쇠나무가 120.7, 중층과 하층에서는 동백나무의 중요치가 각각 61.8, 15.7로 가장 높게 나타났다. 우산고로쇠나무의 중층과 하층에서의 중요치는 각각 37.5, 2.6이었다. 하층에서는 산림청 지정 취약종인 회솔나무가 출현하였다. 층위별 종다양도는 상층 0.674, 중층 0.947, 하층 1.312, 균재도는 상층 0.706, 중층 0.805, 하층 0.938이었다. 우산고로쇠나무 군락의 토양 pH는 5.79, 유기물함량은 7.2%, 전질소 함량은 0.33%, 유효인산 함량은 51.1ppm로 나타났다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2016년도 학술발표회
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• pp.198-198
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• 2016

The Citarum River Basin is the biggest river basin in West Java Province, Indonesia and it plays strategic roles in providing water for irrigation, domestic and industrial uses, and power generation, besides controlling the flood during rainy season. Flowing through seven major cities makes the river flow and water demand are vulnerable to land use change around the river. The present water resources management has involved the regulator, operator, and users in deciding an appropriate water management plan for the entire basin. The plan includes an operation plan for three reservoirs, construction or maintenance of the river channel, and water allocation for all users along the river. Following this plan, a smaller operation group will execute and evaluates the plan based on the actual flow condition. Recently, a deforestation, environment degradation, river sedimentation, a rapid growth of population and industry, also public health become new issues that should be considered in water basin planning. Facing these arising issues, a new development program named ICWRMIP was established to advance the existing management system. This program includes actions to strengthen institutional collaboration, do the restoration and conservation of the river environment, improve water quality and public health, also advance the water allocation system. At present, the water allocation plan is created annually based on a forecasted flow data and water usage prediction report. Sometimes this method causes a difficulty for the operator when the actual flow condition is not the same as the prediction. Improving existing system, a lot of water allocation studies, including a development of the database and water allocation simulation model have been placed to help stakeholders decide the suitable planning schemes. In the future, this study also tries to contribute in advancing water allocation planning by creating an optimization model which ease stakeholders discover a suitable water allocation plan for individual users.

• Annals of Occupational and Environmental Medicine
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• 제34권
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• pp.8.1-8.11
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• 2022

Background: As self-employed workers are vulnerable to health problems, this study aimed to analyze mental health problems and sleep disturbances among self-employed workers compared with paid workers in Korea. Methods: A total of 34,750 workers (23,938 paid workers and 10,812 self-employed workers) were analyzed from the fifth Korean Working Condition Survey, which included 50,205 households collected by stratified sampling in 2017. To compare mental health problems and sleep disturbance among self-employed workers and paid workers, multivariate logistic regression analyses were performed. Results: The odds ratio in self-employed workers compared with paid workers was 1.25 (95% confidence interval [CI]: 1.09-1.42) for anxiety, 1.11 (95% CI: 1.04-1.17) for overall fatigue, 1.11 (95% CI: 1.04-1.20) for difficulty falling asleep, 1.10 (95% CI: 1.02-1.18) for difficulty maintaining sleep and 1.24 (95% CI: 1.16-1.32) for extreme fatigue after waking up. Conclusions: Self-employed workers in Korea have a higher risk of self-reported mental health problems and sleep disturbances than paid workers. Further studies with a longitudinal design and structured evaluation are required to investigate the causal relationship between health problems and self-employment.

• Nuclear Engineering and Technology
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• 제44권3호
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• pp.343-354
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• 2012

Primary water stress corrosion cracking (PWSCC) is a major safety concern in the nuclear power industry worldwide. PWSCC is known to initiate only in the condition in which sufficiently high tensile stress is applied to alloy 600 tube material or alloy 82/182 weld material in pressurized water reactor operating environments. However, it is still uncertain how much tensile stress is re-quired to generate PWSCC or what causes such high tensile stress. This study was performed to pre-dict the magnitude of weld residual stress and operating stress and compare it with previous experi-mental results for PWSCC initiation. For the study, a pressurizer safety nozzle was selected because it is reported to be vulnerable to PWSCC in overseas plants. The assessment was conducted by nu-merical analysis. Before performing stress analysis for plant conditions, a preliminary mock-up ana-lysis was done. The result of the preliminary analysis was validated by residual stress measurement in the mock-up. After verification of the analysis methodology, an analysis under plant conditions was conducted. The analysis results show that the stress level is not high enough to initiate PWSCC. If a plant is properly welded and operated, PWSCC is not likely to occur in the pressurizer safety nozzle.