• Applied Biological Chemistry
• /
• v.25 no.2
• /
• pp.83-92
• /
• 1982

In an anaerobic incubation of uniformly ring-labeled $^{14}C-butachlor$ in two Korean soils for 3 months, very little $^{14}CO_2$ and volatile products were measured. In soil A, 77.52 and 45.36% of the sterile and viable soil radioactivity, respectively, were methanol-extractable and the rest were adsorbed in soil; whereas in soil B, 58.85 and 37.23%, respectively, were methanol-extractable and the rest remained in soil. The adsorption of $^{14}C-butachlor$ depends on the characteristics of the soils. The major metabolite was 2,6-diethyl-N-(butoxymethyl) acetanilide. 2,6-Diethylaniline and 2,6-diethylacetanilide turned out to be the minor metabolites on GLC-MS.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.58 no.1
• /
• pp.81-90
• /
• 2016

The Agricultural Systems Application Platform (ASAP) provides bottom-up modelling and simulation environment for agricultural engineer. The purpose of this study is to expand usability of the ASAP to the second order partial differential equations: elliptic equations, parabolic equations, and hyperbolic equations. The ASAP is a general-purpose simulation tool which express natural phenomenon with capsulized independent components to simplify implementation and maintenance. To use the ASAP in continuous problems, it is necessary to solve partial differential equations. This study shows usage of the ASAP in elliptic problem, parabolic problem, and hyperbolic problem, and solves of static heat problem, heat transfer problem, and wave problem as examples. The example problems are solved with the ASAP and Finite Difference method (FDM) for verification. The ASAP shows identical results to FDM. These applications are useful to simulate the engineering problem including equilibrium, diffusion and wave problem.

• Journal of Information Processing Systems
• /
• v.3 no.2
• /
• pp.43-53
• /
• 2007

The use of agent paradigm in today's applications is hampered by the security concerns of agents and hosts alike. The agents require the presence of a secure and trusted execution environment; while hosts aim at preventing the execution of potentially malicious code. In general, hosts support the migration of agents through the provision of an agent server and managing the activities of arriving agents on the host. Numerous studies have been conducted to address the security concerns present in the mobile agent paradigm with a strong focus on the theoretical aspect of the problem. Various proposals in Intrusion Detection Systems aim at securing hosts in traditional client-server execution environments. The use of such proposals to address the security of agent hosts is not desirable since migrating agents typically execute on hosts as a separate thread of the agent server process. Agent servers are open to the execution of virtually any migrating agent; thus the intent or tasks of such agents cannot be known a priori. It is also conceivable that migrating agents may wish to hide their intentions from agent servers. In light of these observations, this work attempts to bridge the gap from theory to practice by analyzing the security mechanisms available in Aglet. We lay the foundation for implementation of application specific protocols dotted with access control, secured communication and ability to detect tampering of agent data. As agents exists in a distributed environment, our proposal also introduces a novel security framework to address the security concerns of hosts through collaboration and pattern matching even in the presence of differing views of the system. The introduced framework has been implemented on the Aglet platform and evaluated in terms of accuracy, false positive, and false negative rates along with its performance strain on the system.

• Korean Journal of Health Education and Promotion
• /
• v.14 no.1
• /
• pp.47-62
• /
• 1997

본 연구는 한국 보건전문가들의 보건행동을 조사하고, 보건행동간의 상호 관련 요인과 보건행동에 영향을 미치는 인구학적 요인을 분석하는데 그 목적이 있다. 본 연구 대상으로는 한국보건협회 산하의 8개의 보건 관련 학회 중에서 보건교육과 가장 관련이 있는 한국보건교육학회(212명)와 한국보건 간호학회 (124명) 회원 336명이 선정되었다. 본 연구의 도구는 미국에서 이미 실시된 여러 보건행동 연구를 기초로 하여 focus group discussion, back-translation, 전문가들의 panel discussion, 그리고 pilot test(사전조사)를 통하여 한국인의 보건행동 연구를 위해 타당하게 개발되었다. 본 연구를 위하여 1995년 약 두달동안(11월, 12월), 3차에 걸친 우편설문조사를 실시하여 64.3%의 응답회수율을 보였고, 응답자들의 보건행동을 분석하기 위해서 factor analysis(요인분석)와 ANOVA (변량분석) 방법을 사용하였다. 본 연구의 결과는 다음과 같다. 1. 조사응답자의 분포는 남자가 33.8%, 여자가 66.2%였고, 응답자의 80.3%가 석사 이상의 학위를 소유하고 있었다. 응답자들의 전공분야는 다양하였고, 그들 중에서 36.3%가 간호학, 24.4%가 공중보건학을 전공하였다. 응답자 중 과반수 이상이 학교에 근무하였고, 서울에 거주하였으며, 응답자의 평균 직장 근무연수는 14년 이였다. 2. 응답자들의 보건행동에 대한 요인분석 적용의 적합성을 사전검증하기 위하여 Bartlett’s Test of Sphericity (630.37, p〈.00)를 실시하였다. 응답자들의 보건행동을 요인분석한 결과, 17개의 보건행동으로 구성된 네가지 보건행동요인들이 추출되었다. 응답자들의 네가지 보건행동요인들은 다음과 같다: (1) 규칙적인 식사 및 과일 섭취 (2) 음주 및 흡연 (3) 외식,간식 및 카페인 음료 섭취 (4) 운동 및 휴식 3. 응답자들의 인구학적 요인과 네가지 보건행동요인들과의 관계를 분석한 결과, 성별(F=69.59, df=1,203, p〈.05), 교육정도(F=3.48, df=3,199, p〈.05) 그리고 직장(F=4.04, df=3,201, p〈.05)에 따라 음주 및 흡연 행동에 커다란 차이를 보였다. 또한 응답자의 직장 근무연수(F=2.39, df=5,185, p〈.05)에 따라 운동 및 휴식 행동에 커다란 차이를 보였다.

• Journal of the Korean Ceramic Society
• /
• v.42 no.5 s.276
• /
• pp.308-313
• /
• 2005

In this study the electrical conductivity of excess BaO in $BaTiO_3$ was measured to investigate the relationship between defects and solubility in the temperature range of $900^{\circ}C$ to $1300^{\circ}C$ under various oxygen partial pressure. First of all, quenched $BaTiO_3$ powders of various Ba/Ti ratios were analysed by X-ray diffraction to confirm whether second phase is formed or not. As the results, we observed the solubility of BaO in the temperature range of $1200^{\circ}C$ to $1400^{\circ}C$, and it was also found that the conductivity minima move to lower $PO_2$ with increasing excess BaO within solubility limit.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.04b
• /
• pp.165-170
• /
• 2004

MLCC의 주재료인 $BaTiO_3$는 금속전극의 산화를 방지하기 위해 환원분위기에서 소결하는데 이는 비화학양론적 조성 및 전기적 성질, 결함 그리고 상의 변화를 가져온다. 본 연구에서는 상의 변화를 다양한 온도 범위에서 BaO 또는 $TiO_2$를 첨가시킨 $BaTiO_3$ powder을 가지고 급냉시킨 후 이를 X-선 회절 분석을 통하여 이들의 이차상 형성 여부 등을 조사하였다. $1320^{\circ}C$에서는 $TiO_2$의 고용도가 BaO의 고용도에 비해 상당히 큰 값을 가짐을 알 수 있었다. 이런 결과를 바탕으로 Ba/Ti 비, 산소분압 및 온도에 따른 $BaTiO_3$의 전기전도도 거동에 의하면, 고용범위내에서 BaO 첨가량이 증가할수록 전기전도도의 최소점은 낮은 산소분압쪽으로 이동함을 관찰하였으며 이는 $Ti^{4+}$빈자리에 따른 산소빈자리가 형성되는 결함 모델로 설명되어진다.

• Anxiety and mood
• /
• v.11 no.1
• /
• pp.47-53
• /
• 2015

Objective : Generalized anxiety disorder (GAD) is a common anxiety disorder characterized by excessive worries and anxiety symptoms. To distinguish between pathological and normal worries, this study compared the contents and severity of worries among patients with GAD with those of matched non-psychiatric control Methods : Thirty outpatients with GAD receiving treatment at the psychiatric department of Hanyang University Guri Hospital were recruited. As a matched control group, we selected 30 adults without psychiatric history who participated in the Anxiety Disorder Survey, during the Mental Health Exposition held in Seoul in April, 2014. Matched demographic data were age, sex, education, and household income. Self-questionnaires included demographic data, contents of worry (10 categories of worries and each severity), and the Pennsylvania State Worry Questionnaire (PSWQ). Results : There was no statistical difference in the contents of worry between patient and control groups. However, the total PSWQ scores significantly higher in the GAD group. Conclusion : Our findings suggest that patients and non-patients worry about the similar contents and worries in GAD cannot be differentiated by what people worry about. Only the severity of worry was a distinguishable feature. Our finding supported inclusion of the diagnostic criterion of "excesslve wornes" in GAD.

• Ocean and Polar Research
• /
• v.27 no.2
• /
• pp.189-195
• /
• 2005

Several models predict large and potentially abrupt ocean circulation changes due to anthropogenic greenhouse-gas emissions. These circulation changes drive-in the models-considerable oceanic oxygen trend. A sound estimate of the observed oxygen trends can hence be a powerful tool to constrain predictions of future changes in oceanic deepwater formation, heat and carbon dioxide uptake. Estimating decadal scale oxygen trends is, however, a nontrivial task and previous studies have come to contradicting conclusions. One key potential problem is that changes in the historical observation network might introduce considerable errors. Here we estimate the likely magnitude of these errors for a subset of the available observations in the Southern Ocean. We test three common data analysis methods south of Australia and focus on the decadal-scale trends between the 1970's and the 1990's. Specifically, we estimate errors due to sparsely sampled observations using a known signal (the time invariant, temporally averaged, World Ocean Atlas 2001) as a negative control. The crossover analysis and the objective analysis methods are for less prone to spatial sampling location biases than the area averaging method. Subject to numerous caveats, we find that errors due to sparse sampling for the area averaging method are on the order of several micro-moles $kg^{-1}$. for the crossover and the objective analysis method, these errors are much smaller. For the analyzed example, the biases due to changes in the spatial design of the historical observation network are relatively small compared to the tends predicted by many model simulations. This raises the possibility to use historic oxygen trends to constrain model simulations, even in sparsely sampled ocean basins.

• Journal of Welding and Joining
• /
• v.26 no.2
• /
• pp.62-68
• /
• 2008

Effects of gravitational orientation on gas tungsten arc welding (GTAW) for 304 stainless steel were studied to determine the critical factors for weld pool formation, such as weld surface deformation and weld pool shape. This study was accomplished through an analytical study of weld pool stability as a function of primary welding parameters (arc current and arc holding time), material properties (surface tension and density), and melting efficiency (cross-sectional area). The stability of weld pool shape and weld surface deformation was confirmed experimentally by changing the welding position. The arc current and translational velocity were the major factors in determining the weld pool stability as a function of the gravitational orientation. A 200A spot GTAW showed a significant variation of the weld pool formation as the arc held longer than 3 seconds, however the weld pool shape and surface morphology for a 165A spot GTAW were 'stable', i.e., constant regardless of the gravitational orientation. The cross-sectional area of the weld (CSA) was one of the critical factors in determining the weld pool stability. The measured CSA ($13.5mm^2$) for the 200A spot GTAW showed a good agreement with the calculated CSA ($14.9mm^2$).

• Korean Journal of Plant Tissue Culture
• /
• v.24 no.5
• /
• pp.273-277
• /
• 1997

The sesquiterpene cyclase (SC) was induced and its products were accumulated in the culture media of Hyoscyamus muticus hairy roots by addition of Rhizoctonia solani extracts. The cumulative production of solavetivone was nearly doubled by integrated extraction of the products from the media during the 24 h accumulation period. Western blots with monoclonal antibodies against SC show that the enzyme levels are the same for both extracted and non-extracted cultures. SC activities measured in vitro with radioactive substrate are not significantly different. These results suggest that productivity is controlled by substrate availability within the terpenoid pathway, and feedback regulation precedes the branch-point enzyme sesquiterpene cyclase.