• 한국산학기술학회논문지
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• 제14권6호
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• pp.2717-2726
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• 2013

본 연구는 청소년 탄력성이 학습동기에 직접적으로 미치는 영향을 연구함으로써 외적보호요인 강화 이론을 검증하는 것이다. 연구방법은 경기도 E시에 소재한 일반고 고등학생을 대상으로 2013년 3월 5일부터 1주일간 설문조사를 실시하였다. 자료 분석은 빈도분석, 일원변량분석, 상관분석, 다중회귀분석 등으로 분석하였다. 분석결과는 가정차원의 상호작용, 지역사회차원의 돌봄과 기대가 높을수록 내재적 학습동기의 '수행과정에 주의를 집중'이 높았다. 그리고 학교차원의 돌봄과 기대가 높을수록, 학교차원의 상호작용이 낮을수록 내재적 학습동기의 '적절한 모험성과 도전추구'가 높게 나타났다. 연구결과, 청소년 탄력성의 외적보호요인을 강화함으로써 내재적 학습동기를 높일 수 있음을 입증하였다. 본 연구의 시사점은 청소년 문제와 학업중단사태를 해결하기 위한 프로그램 개발 및 정책에 활용할 수 있는 이론적 근거를 제시하였다는 것이다.

• 한국산학기술학회논문지
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• 제14권5호
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• pp.2131-2139
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• 2013

본 연구는 청소년 탄력성과 자살충동과의 상관성을 명확하게 파악하여, 외적보호요인을 강화하는 보다 효과적인 청소년 자살예방 대안 제시를 목적으로 한다. 연구대상은 경기도에 소재하는 일반고 고등학교 1학년 남녀 학생 243명이며 2013년 3월 5일부터 1주일간 설문조사를 실시하였다. 분석방법은 빈도분석, 상관분석, 다중회귀분석, t-test, 일원변량분석 등을 실시하였고, 실증분석은 모두 유의수준 5%에서 검증하였다. 연구결과는 자살충동과 탄력성은 부의 상관관계가 있었으며, 특히 가정차원의 상호작용이 높을수록, 또래차원과 학교차원의 돌봄과 기대가 높을수록 자살충동이 낮았다. 본 연구의 시사점은 청소년 탄력성이 자살충동에 미치는 영향에 대한 연구결과를 바탕으로 자살예방정책마련을 위한 자료가 될 것으로 사료된다.

• 한국보육지원학회지
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• 제8권1호
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• pp.25-44
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• 2012

본 연구는 지난 10년간의 보육교사 이직의도와 관련된 선행연구를 바탕으로 이직의도를 억제하는 변인들의 효과크기를 메타분석을 통해 검증하였고 메타회귀분석을 통해 조사시기와 조사지역에 따른 변화추이를 검증하였다. 연구대상으로는 분석을 위해 효과크기 변환이 가능한 논문 33편을 선정하였다. 연구결과 이직의도와 관련된 억제변인군의 효과크기는 조직외면적, 직무, 조직내면적변인군 순으로 나타났고, 세변인군 모두 중간효과크기를 가지고 있는 것으로 나타났다. 조직외면적변인군의 하위변인은 근로시간의 효과크기가 가장 큰 것으로 나타났으며, 직무변인군의 하위변인은 교사효능감과 직무만족이 큰 효과크기를 가진 것으로 나타났다. 또한 조직내면적변인군의 하위변인은 대인관계와 원장과의 관계의 관계가 큰 효과크기를 가진 것으로 나타났다. 조사대상, 조사년도에 따른 이직의도 억제와 관련된 변인의 메타회귀분석 결과 모든 연구 개념들이 통계적으로 유의미한 차이가 없는 것으로 나타났다. 그러나 변인들에 대한 상관분석 결과, 복지후생은 수도권외지역보다 수도권지역일 수록 효과크기가 큰 것으로 나타났다.

• 한국사회복지학
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• 제55권
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• pp.255-281
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• 2003

본 연구는 아내폭력가정 자녀들을 대상으로 그들의 적응과 관련된 변인들을 탐색하는데 목적을 두고 있다. 구체적으로, 쉼터아동과 일반아동들이 내 외적 적응행동에서 차이가 있는지 확인하였다. 폭력 경험의 유형에 따라 표출하는 문제행동이 다른지 살펴보고, 적응력이 높은 아동과 부적응이 심한 집단을 구별하는 요인들을 발견하였다. 또한 어떤 보호요인들이 어떤 경로를 통해서 적응에 영향을 미치는지 검증하였다. 본 연구의 표본은 가정폭력 쉼터에 거주한 72명 아동과 그들 어머니, 그리고 76명 비폭력가정 아동과 어머니들이다. 일원변량분석, 로지스틱 회귀모델, 경로분석을 사용해서 밝혀진 결과를 요약하면 다음과 같다. 첫째, 아내폭력가정 아동은 비교집단보다 학업성취도가 낮고, 우울/불안 수준이 높으며, 더 공격적이거나 잦은 횟수의 비행행동을 보이고 있었다. 둘째, 아내폭력만 목격한 아동과 아내폭력 목격과 동시에 신체적 폭력도 경험한 집단을 구별하는 요인은 공격성과 비행행동으로 밝혀졌다. 셋째, 학업성취도에 대한 보호요인은 사회적 지지이며, 비행행동의 예측요인은 어머니의 학력, 소득, 아동의 연령, 사회적 지지로 나타났다. 넷째, 아내폭력은 아동의 적응행동에 직접적인 영향을 미치고 있었으며, 아울러 학업성취도와 자존감을 매개로 하여 간접효과를 갖는 것으로 나타났다. 다섯째, 아내폭력은 어머니의 우울 정서 또는 아동의 사회적 지지에 의해 학업성취도에 간접적으로 영향을 미치는 것으로 밝혀졌다. 이러한 결과를 바탕으로 폭력가정 아동의 적응력을 높이기 위한 실천적 방법들이 제시되었다.

• Journal of Mechanical Science and Technology
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• 제18권4호
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• pp.592-596
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• 2004

Corrosion is never avoided in the use of materials with various environments. The underwater hull is normally protected against rusting by several coatings of anti-corrosive paint. The purpose of ICCP(Impressed Current Cathodic protection) system is to eliminate the rusting or corrosion, which occurs on metal immersed in seawater. The anode of ICCP system is controlled by an external DC source with converter. The function of anode is to conduct the protective current into seawater. The proposed algorithm includes the harmonic suppression control strategy and the optimum protection strategy and has tried to test the requirement current density for protection, the influence of voltage, the protection potential. This paper was studied the variation of potential and current density with environment factors, time and velocity, and the experimental results will be explained.

• 보건교육건강증진학회지
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• 제22권4호
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• pp.137-154
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• 2005

Objectives: This study aims to examine the positive effects of developmental assets on the prevention of health risk behaviors among Korean adolescents. The framework of developmental assets was introduced as building blocks for healthy child and adolescent development by Benson and his colleagues. These assets represent positive external environmental factors and internal personal qualities which strongly influence the quality of life of adolescents. Methods: In 2001, we administered self-reported questionnaires to 3,739 girls and boys in grade 9 at eight schools in two cities, Chinju and Suwon in South Korea. The data was compiled into a 'Korean Youth Health Related Behaviors and Developmental Assets Survey' and then analyzed Youth health risk behaviors, which we measured in terms of their frequency, included tobacco, alcohol, and substance use, sexual intercourse, anti-social behaviors, violence, feelings of social isolation at school, depression or attempted suicide, absenteeism from school, gambling. Results: Overall, with respect to developmental assets, the Korean adolescents surveyed only 12.6 of the 40 assets, and 88 percent of adolescents had 20 or fewer of the assets. Based on their number of developmental assets(DA), adolescents were categorized into four groups: Group I(DA 0-10): Group II(DA 11-20): Group III(DA 21-30): Group IV(DA 31-40). We examined the differences in the frequency of each health risk behavior across the four groups, Group I-IV, and found that the frequency of most health risk behaviors decreased as the number of developmental assets increased. Conclusion: We therefore concluded that in order to make effective approaches for the prevention of health risk behaviors among adolescents, we should consider and develop more comprehensive and adolescents-based policy and programs to promote various aspects of adolescents' health and quality of life.

• Corrosion Science and Technology
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• 제15권6호
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• pp.271-280
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• 2016

An approach to achieving the ambitious goal of cost effectively extending the safe operation life of energy pipeline to 100 years is the application of health monitoring and life prediction tools that are able to provide both long-term remnant pipeline life prediction and in-situ pipeline condition monitoring. A critical step is the enhancement of technological capabilities that are required for understanding and quantifying the effects of key factors influencing buried steel pipeline corrosion and environmentally assisted materials degradation, and the development of condition monitoring technologies that are able to provide in-situ monitoring and site-specific warning of pipeline damage. This paper provides an overview of our current research aimed at developing new sensors and electrochemical cells for monitoring, categorising and quantifying the level and nature of external pipeline and coating damages under the combined effects of various inter-related variables and processes such as localised corrosion, coating cracking and disbondment, cathodic shielding, transit loss of cathodic protection.

• Computers and Concrete
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• 제19권4호
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• pp.413-417
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• 2017

Concrete is a material popularly used in construction. Due to the load-bearing and external environmental factors during utilization or manufacturing, its surface is prone to flaws, such as crack and leak. To repair these superficial defects and ultimately and avoid the deterioration of the concrete's durability, numerous concrete surface protective coatings and crack repair products have been developed. Currently, studies are endeavoring to exploit the mineralization property of microbial strains for repairing concrete cracks be the repairing material for crack rehabilitation. This research aims to use bacteria, specifically B. pasteurii, in crack rehabilitation to enhance the flexural and compression strength of the repaired concrete. Serial tests at various bacterial concentrations and the same $Urea-CaCl_2$ medium concentration of 70% for crack rehabilitation were executed. The results prove that the higher the concentration of the bacterial broth, the greater the amount of calcium carbonate precipitate was induced, while using B. pasteurii broth was for crack rehabilitation. The flexural and compression strengths of the repaired concrete test samples were the greatest at 100% bacterial concentration. Compared to the control group (bacterial concentration of 0%), the flexural strength had increased by 32.58% for 1-mm crack samples and 51.01% for 2-mm crack samples, and the compression strength had increased by 28.58% and 23.85%, respectively. From the SEM and XRD test results, a greater quantity of rectangular and polygonal crystals was also found in samples with high bacterial concentrations. These tests all confirm that using bacteria in crack rehabilitation can increase the flexural and compression strength of the repaired concrete.

• Journal of Magnetics
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• 제16권1호
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• pp.36-41
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• 2011

If gas is leaking out of gas pipelines, it could cause a huge explosion. Accordingly, it is important to ensure the integrity of gas pipelines. Traditionally, over the years, gas-operating companies have used the ILI system, which is based on axial magnetic flux leakage (MFL), to inspect the gas pipelines. Relatively, there is a low probability of detection (POD) for the axial defects with the axial MFL-based ILI. To prevent the buried pipeline from corrosion, it requires a protective coating. In addition to the potential damage to the coating by environmental factors and external forces, there could be defects on the damaged coating area. Thus, it is essential that nondestructive evaluation methods for detecting axial defects (axial cracks, axial groove) and damaged coating be developed. In this study, an electromagnetic acoustic transducer (EMAT) sensor was designed and fabricated for detecting axial defects and coating disbondment. In order to validate the performances of the developed EMAT sensor, experiments were performed with specimens from axial cracks, axial grooves, and coating disbondment. The experimental results showed that the developed EMAT sensor could detect not only the axial cracks (minimum 5% depth of wall thickness) and axial grooves (minimum 10% depth of wall thickness), but also the coating disbondment.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4146-4158
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• 2022

Ultra-high performance concrete (UHPC) has been widely utilized in military and civil protective structures to resist intensive loadings attributed to its excellent properties, e.g., high tensile/compressive strength, high dynamic toughness and impact resistance. At present, aiming to improve the defects of the traditional vertical concrete cask (VCC), i.e., the external storage facility of spent fuel, with normal strength concrete (NSC) shield, e.g., heavy weight and difficult to fabricate/transform, the feasibility of UHPC applied in the shield of VCC is numerically examined considering its high radiation and corrosion resistance. Firstly, the finite element (FE) analyses approach and material model parameters of NSC and UHPC are verified based on the 1/3 scaled VCC tip-over test and drop hammer test on UHPC members, respectively. Then, the refined FE model of prototypical VCC is established and utilized to examine its dynamic behaviors and damage distribution in accidental tip-over and end-drop events, in which the various influential factors, e.g., UHPC shield thickness, concrete ground thickness, and sealing methods of steel container are considered. In conclusion, by quantitatively evaluating the safety of VCC in terms of the shield damage and vibrations, it is found that adopting the 300 mm-thick UHPC shield instead of the conventional 650 mm-thick NSC shield can reduce about 1/3 of the total weight of VCC, i.e., about 50 t, and 37% floor space, as well as guarantee the structural integrity of VCC during the accidental drop simultaneously. Besides, based on the parametric analyses, the thickness of concrete ground in the VCC storage site is recommended as less than 500 mm, and the welded connection is recommended for the sealing method of steel containers.