• 한국응용곤충학회지
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• 제57권4호
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• pp.261-269
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• 2018

아카시아진딧물은 다양한 기주식물을 먹이로 하는 곤충으로 전 세계적으로 분포하고 있다. 본 연구는 아카시아진딧물 약충의 발육기간, 무시성충의 수명과 번식능력을 조사하기 위하여 10.0, 15.0, 20.0, 25.0, 30.0, $32.5^{\circ}C$ 정온조건에서 실험을 실시하였다. 조사된 모든 항온조건에서 아카시아진딧물은 성공적으로 성충으로 발육하였고 발육율은 온도가 상승할수록 증가하였다. 아카시아진딧물 약충시기별 발육영점온도와 유효적산일은 선형회귀분석 방법을 이용하여 계산하였다. SSI모델을 이용하여 발육최저, 최고한계를 추정하였다. 아카시아진딧물 전체약충기간의 발육영점온도와 유효적산일은 각각 $5.3^{\circ}C$과 128.4DD였다. SSI모델을 이용한 아카시아진딧물의 발육최저, 최고온도는 $17.0^{\circ}C$과 $34.6^{\circ}C$였으며 이들간의 차이는 $17.5^{\circ}C$였다. 전체약충기간의 발육완료분포모형은 3-매개변수 Weibull함수를 이용하여 나타내었다. 온도와 관련된 아카시아진딧물의 생물적 특성을 생명표분석을 통해 나타내었다. 내적자연증가율은 $25^{\circ}C$에서, 개체군순증가율은 $20^{\circ}C$에서 가장 높았다. 다른 지역에 서식하는 아카시아진딧물의 생물적 특성을 비교 분석하였다.

• 사회복지연구
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• 제48권3호
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• pp.209-232
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• 2017

본 연구는 한국의 심각한 노인빈곤문제 해결을 위해 노인소득보충급여제도 도입 방안을 제시한다. 이를 위해 노인소득보충급여제도를 운용하고 있는 선진국의 경험을 토대로 한국의 노인소득보충급여 모델을 설계하고, 모델의 정책적 효과와 재원규모를 실증 분석하였다. 분석결과를 통한 정책적 시사점은 다음과 같다. 먼저, 보충급여가 빈곤에 처한 노인의 상당수를 포괄가능하며, 노인의 빈곤 및 소득불평등 감소에 상당한 영향을 주는 것으로 나타났다. 둘째, 보충급여제도는 기초연금보다 재원효율성 제고 측면에서 더 효과적이다. 동일한 금액을 보장할 때 기초연금보다 보충급여의 재원규모가 훨씬 적었다. 마지막으로 기초연금과 보충급여제도의 조합에 따라 정책적 효과와 재원규모의 차이가 발생해 정책적 우선순위에 따라 적절한 조합을 구성하여 견고한 노후소득보장체계를 구축하여야 하겠다.

• 한국심리학회지 : 문화 및 사회문제
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• 제19권3호
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• pp.389-407
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• 2013

본 연구는 문제해결능력과 자살사고와의 관계에서 우울의 매개효과를 검증하고자 하였다. 이를 위해 대학생 548명을 대상으로 지각된 문제해결능력 척도, 우울 척도 및 자살사고 척도를 실시하였다. 이들 변인들 간의 관계를 알아보기 위해 상관 분석하였고, 우울의 매개효과를 검증하기 위하여 회귀분석을 실시하였다. 연구 결과 문제해결능력과 우울 및 자살사고 간에 유의한 정적 상관을 보였고, 문제해결능력과 자살사고 간의 관계에서 우울의 매개효과가 검증되었다. 즉 지각된 문제해결능력은 자살사고에 직접 영향을 미치기보다는 우울을 매개로 간접적으로 영향을 미치는 것으로 확인되었다. 이 같은 연구결과는 자살사고에 영향을 미치는 우울과 문제해결능력에 대한 중재의 중요성을 시사하였다.

• Structural Engineering and Mechanics
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• 제49권1호
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• pp.1-22
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• 2014

A seismic evaluation is made of the response to horizontal ground shaking of cantilever retaining walls using the finite element model in three dimensional space whose verification is provided analytically through the modal analysis technique in case of the assumptions of fixed base, complete bonding behavior at the wall-soil interface, and elastic behavior of soil. Thanks to the versatility of the finite element model, the retained medium is then idealized as a uniform, elastoplastic stratum of constant thickness and semi-infinite extent in the horizontal direction considering debonding behavior at the interface in order to perform comprehensive soil-structure interaction (SSI) analyses. The parameters varied include the flexibility of the wall, the properties of the soil medium, and the characteristics of the ground motion. Two different finite element models corresponding with flexible and rigid wall configurations are studied for six different soil types under the effects of two different ground motions. The response quantities examined incorporate the lateral displacements of the wall relative to the moving base and the stresses in the wall in all directions. The results show that the wall flexibility and soil properties have a major effect on seismic behavior of cantilever retaining walls and should be considered in design criteria of cantilever walls. Furthermore, the results of the numerical investigations are expected to be useful for the better understanding and the optimization of seismic design of this particular type of retaining structure.

• 대한불안의학회지
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• 제10권2호
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• pp.151-156
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• 2014

Objective : The aim of this study is to analyze the relationship among job stress, depression, and suicidal ideation in firefighters, particularly the mediating effects of depression. Methods : The subjects were 2,136 firefighters in Gangwon-do, who completed the short form of Korean occupational stress scale (KOSS-SF), Korean version of the Beck depression inventory (K-BDI), and the revised scale for suicide ideation (SSI) online in mental health promotion service of firefighters. The data was analyzed with correlation analysis among the variables, and the multiple regression analysis method of Bar-on and Kenny (1986) was used. Results : Job stress showed positive correlations with depression (r=0.493, p <0.01) and suicidal ideation (r=0.296, p<0.01). Depression showed a positive correlation with suicidal ideation (r=0.561, p<0.01). The result of analyzing the mediating effect of depression showed that depression was a full mediator variable between job stress and suicidal ideation. Conclusion : Based on the results, it is very likely that job stress may affect suicidal ideation via depression. These results suggested that the preventive interventions emphasized on depression may be helpful for reduction of suicide in firefighters.

• Structural Engineering and Mechanics
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• 제89권4호
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• pp.421-436
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• 2024

This research addresses experimentally the relationship between the excitation frequency and both hoop and axial wall stresses in a water storage tank. A low-density polyethylene tank with six different aspect ratios (water level to tank radius) was tested using a shake table. A laminar box with sand represents a soil site to simulate Soil-Structure Interaction (SSI). Sine excitations with eight frequencies that cover the first free vibration frequency of the tank-water system were applied. Additionally, Ricker wavelet excitations of two different dominant frequencies were considered. The maximum stresses are compared with those using a nonlinear elastic spring-mass model. The results reveal that the coincidence between the excitation frequency and the free-vibration frequency of the soil-tank-water system increases the sloshing intensity and the rigid-like body motion of the system, amplifying the stress development considerably. The relationship between the excitation frequency and wall stresses is nonlinear and depends simultaneously on both sloshing and uplift. In most cases, the maximum stresses using the nonlinear elastic spring-mass model agree with those from the experiments.

• 한국과학교육학회지
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• 제42권1호
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• pp.111-125
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• 2022

ENACT 프로젝트는 과학기술과 관련한 사회쟁점(SSI)에 관심을 갖고 쟁점해결에 참여해보는 경험을 통해 사회적 책임감을 함양하는 교육프로그램으로, 본 연구에서는 ENACT 프로젝트 수행을 통해 예비 과학교사들의 과학기술자의 사회적 책임에 대한 인식이 어떻게 변화하는지 탐색해보았다. 32명의 예비 과학교사가 비교과활동으로 약 3개월에 걸쳐 자발적으로 참여하였으며, ENACT 모형 즉, 쟁점발견, 쟁점탐색, 미래상황 예측, 과학·기술·공학적 쟁점해결, 사회적 실천의 5단계에 따라 진행하였다. 예비 과학교사들의 과학기술자의 사회적 책임에 대한 인식 변화를 탐색하기 위해 혼합연구방법을 이용하였으며, 이를 위해 과학기술자의 사회적 책임인식을 측정하는 검사도구(VSRoSE)와 조별 면담 자료를 수집하였다. 연구결과, 예비 과학교사들은 VSRoSE 전체 및 8개 하위요인 중 5개 요인에서 통계적으로 유의미한 향상을 나타내었다. 각 하위 요인별 예비 교사들의 면담을 분석한 결과, 이들은 과학기술에 대한 인식론적 탐색을 강조하는 Cycle I과 쟁점해결과 실천을 강조하는 Cycle II를 수행하는 과정에서 과학기술자의 사회적 역할에 대해 고민할 수 있는 기회를 충분히 갖게 되었음을 확인하였다. 특히 프로젝트 참여 전 과학기술이 인간과 환경, 사회에 미치는 영향을 고려해야 한다는 것에 초점을 두었던 예비 교사들의 인식은, 프로젝트 참여 후 사회적 필요와 요구를 반영하고 지역사회 문제 해결을 위해 대중과 협력·소통하며 정책에 참여해야 하는 것까지 확장해서 이해하는 모습을 보였다. 위 결과를 기반으로 과학기술관련 사회쟁점 교육과 교사교육에 있어 본 연구의 시사점을 제시하였다.

• Earthquakes and Structures
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• 제12권6호
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• pp.689-697
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• 2017

Nowadays, there are a great number of various structures that have been retrofitted by using different FRP Composites. Due to this, more researches need to be conducted to know more the characteristics of these structures, not only that but also a comparison among them before and after the retrofitting is needed. In this research, a model steel structure is tested using a bench-scale earthquake simulator on the shake table, using recorded micro tremor data, in order to get the dynamic behaviors. Beams of the model steel structure are then retrofitted by using CFRP composite, and then tested on the Quanser shake table by using the recorded micro tremor data. At this stage, it is needed to evaluate the dynamic behaviors of the retrofitted model steel structure. Various types of methods of OMA, such as EFDD, SSI, etc. are used to take action in the ambient responses. Having a purpose to learn more about the effects of FRP composite, experimental model analysis of both types (retrofitted and no-retrofitted models) is conducted to evaluate their dynamic behaviors. There is a provision of ambient excitation to the shake table by using recorded micro tremor ambient vibration data on ground level. Furthermore, the Enhanced Frequency Domain decomposition is used through output-only modal identification. At the end of this study, moderate correlation is obtained between mode shapes, periods and damping ratios. The aim of this research is to show and determine the effects of CFRP Composite implementation on structural responses of the model steel structure, in terms of changing its dynamical behaviors. The frequencies for model steel structure and the retrofitted model steel structure are shown to be 34.43% in average difference. Finally, it is shown that, in order to evaluate the period and rigidity of retrofitted structures, OMA might be used.

• Wind and Structures
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• 제30권6호
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• pp.633-648
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• 2020

The objective of this work was to investigate the interference effects of two-parallel bridge decks on aerodynamic coefficients, vortex-induced vibration, flutter instability and flutter derivatives. The two bridges have significant difference in cross-sections, dynamic properties, and flutter speeds of each isolate bridge. The aerodynamic static tests and aeroelastic tests were performed in TU-AIT boundary layer wind tunnel in Thammasat University (Thailand) with sectional models in a 1:90 scale. Three configuration cases, including the new bridge stand-alone (case 1), the upstream new bridge and downstream existing bridge (case 2), and the downstream new bridge and the upstream existing bridge (case 3), were selected in this study. The covariance-driven stochastic subspace identification technique (SSI-COV) was applied to identify aerodynamic parameters (i.e., natural frequency, structural damping and state space matrix) of the decks. The results showed that, interference effects of two bridges decks on aerodynamic coefficients result in the slightly reduction of the drag coefficient of case 2 and 3 when compared with case 1. The two parallel configurations of the bridge result in vortex-induced vibrations (VIV) and significantly lower the flutter speed compared with the new bridge alone. The huge torsional motion from upstream new bridge (case 2) generated turbulent wakes flow and resulted in vertical aerodynamic damping H1^* of existing bridge becomes zero at wind speed of 72.01 m/s. In this case, the downstream existing bridge was subjected to galloping oscillation induced by the turbulent wake of upstream new bridge. The new bridge also results in significant reduction of the flutter speed of existing bridge from the 128.29 m/s flutter speed of the isolated existing bridge to the 75.35 m/s flutter speed of downstream existing bridge.

• 대한불안의학회지
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• 제16권2호
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• pp.76-82
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• 2020

Objective : Previous studies have shown that depression, anxiety and embitterment are highly related to suicide. This study aims to investigate the mediating effect of embitterment between depression, anxiety and suicide. Methods : A total of 174 participants with depressive and anxiety disorders were evaluated with STAI-S, STAI-T, PHQ-9, PTED scale, SSI and suicide attempt history. A mediation analysis using bootstrapping was utilized in order to estimate the indirect effects of depression and anxiety on suicide through embitterment. Results : Embitterment significantly mediated the relationship between depression and suicidal ideation [b=0.291, 95% CI(0.18, 0.40)], and also it mediated the relationship between depression and suicide attempt [b=0.066, 95% CI(0.02, 0.16)]. Although a direct effect of anxiety on suicide attempt was not significant, but embitterment significantly mediated the relationship between anxiety and suicide attempt Conclusion : This suggests that embitterment may be a significant important factor to consider in the relationship between depression, anxiety and suicide. Understanding the mediating role of embitterment on suicide may helpful to prevent suicide.