• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.11 no.1
• /
• pp.167-176
• /
• 1991

Finite element programs are developed, adopting the hyperbolic model and the Cam-clay model. In the hyperbolic model, a new model taking into account the volume change during shear is proposed and a new technique considering the density change underneath a footing is proposed. And a computing algorithm considered as more reasonable than existing one is presented. In the Cam-clay model, the deveoloped program is applied to sand, the case not recorded much, and then it is tried to analiza the behavior of sand from the viewpoint of the critical state concept. For this, the conventional CD triaxial compression tests and the footing model tests are carried out. The results are improved by 60 percent by using the modified hyperbolic model proposed. When the Cam-clay model is applied to sand, a model reflecting the overconsolidation effects and a computing algorithm accounting for the strain softening are needed. The results obtained by using the Cam-clay model are not much influenced by the value of the initial poisson's ratio, but those of the modified hyperbolic model are much influenced by that. So th values of the initial poisson's ratio must be selected deliberately in the numerical analysis.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2003.09a
• /
• pp.33-33
• /
• 2003

목적 : 현재 국내에서 사용되고 있는 방사선치료계획 장비는 거의 모든 방사선종양학과에서 외국 회사의 제품을 사용하고 있는 실정이다. 본 연구는 국내 기술로 개발된 3 차원 조형 방사선치료계획 장비인 Core Plan의 선량계산 알고리즘의 정확성 및 방사선 치료계획 장비로서의 유용성에 관해 평가하고 본 장비의 특징에 대해 간략히 소개하고자 한다. 재료 및 방법 : 본 연구는 2002 년 11 월에 가톨릭대학교 성모병원 방사선종양학과와 서울씨앤제이의 연구계약에 의해 시행되었다. 본 장비에 대한 평가는 방사선분포 및 계산상의 정확성과 임상적용시의 유용성의 관점에서 시행되었다. 본 장비에서 이용된 광자선 선량계산은 Clarkson-Cunningham 모델이며 전자선 선량계산은 2.5D Hogstrom 알고리즘이다. 방사선분포 및 계산상의 정확성 평가를 위하여 방사선치료 장비는 본 병원이 보유한 Clinac 2100CD (Varian, USA)를 이용하였고 폴리스티렌 팬텀과 필름 및 이온 전리함을 이용하여 방사선분포 및 계산상의 정확성을 평가하였다. 방사선분포의 평가 방법은 필름을 이용한 방사선분포의 중심부단면 선량분포와 CorePlan 에서 재현된 방사선분포의 동일면 선량분포를 비교하였다. 임상적용은 2003 년 3 월부터 7 월까지 방사선치료를 받은 50 명의 환자를 대상으로 분석하였다. 본 시험에 적용된 환자는 본 병원이 보유한 3 차원 방사선치료계획 장비인 Prowess 3D (SSGI Inc., USA)를 이용하여 실제 치료된 환자들이며 이 환자를 대상으로 CorePlan에서 동일하게 재현하여 비교하였다. 결과 및 결론 : 방사선분포 및 계산상의 정확성 평가에서는 실제 측정된 결과와 CorePlan에서 재현된 결과가 모두 $\pm$3% 이내로 평가되었다. 50 명의 환자를 대상으로 시행한 임상시험 결과 Prowess 3D에서 나타낸 결과와 비교하여 두경부에서는 1.678%, 흉부 1.578%, 복부 1.271%의 선량값의 오차를 보였다. 본 연구를 진행하는 과정에서 많은 부분의 프로그램 수정이 있었으며 실제임상에 필요한 부분에 대한 추가 및 보완이 이루어졌다. 앞으로 진행될 과정은 실제임상의 사용에 필요한 부분의 계속적인 업그레이드와 전자선에 대한 방사선분포 및 계산정확성 평가, 임상적용에 있어서 Prowess3D 뿐만 아니라 다양한 방사선 치료계획 장비와의 비교를 할 예정이다.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.38 no.1
• /
• pp.49-56
• /
• 2014

In this study, the generation efficiency of the limited area of a concentrator solar cell was increased by using a solar concentrator and a tracking device. Heat generated by the solar cell was collected using a thermal absorber for supplying hot water or heating. Thus, the concentrator solar cell system provided electricity and heat simultaneously. Tracking of the sun by detecting the sun's position, repositioning of heating device towards the east after sunset, and shutting down of system after sunset were successfully implemented using an illuminance sensor (CdS) and Simulink, a commercial software package. We performed parametric analysis of the velocity, fin installation, and entrance location with respect to the operating temperature of the concentrator solar cell. A heat transfer simulation model was developed for comparing the actual temperature profiles of the concentrator solar cell and thermal absorber, and good agreement was found between the results of the simulations and the experiments.

• Journal of Applied Biological Chemistry
• /
• v.54 no.4
• /
• pp.290-295
• /
• 2011

This study was carried out to investigate the quality of soil, irrigation water, and status of agrochemicals application in relation to good agriculture practices system in the major cultivation area of Disocorea batatas. The concentrations of heavy metals as Cd, Pb, Cu, and Zn in soils and irrigation waters were lower than those of standard level for Environmental Conservation Act of Soil and Water in Korea. The dominant weed have been appeared Digitaria sanguinalis and Portulaca oleraceamite. The dominant insect pests and plant pathogens have been appeared aphid and anthracnose. Average yearly application of pesticide was 2 to 4 times for herbicide and 4 to 6 times for plant pathogens and insect pests. In order to safety production of medicinal crops could be achieved by proper cultivation management such as minimum application of agro-chemicals, effective use of by-product fertilizer, and technology development of organic farming.

• Korean Journal of Adult Nursing
• /
• v.15 no.4
• /
• pp.660-669
• /
• 2003

Purpose: The purpose of this study was to identify the effects of self-efficacy promoting program on self-efficacy, self-care, and anxiety in cancer patients receiving chemotherapy. Method: A quasi-experimental nonequivalent control group pre and post design was used. Subjects were 52 cancer patients who received chemotherapy in a hospital. Twenty-six patients were assigned to the experimental and the control groups, respectively. For the experimental group, the CD image for fifteen minutes and two consultations for about ten minutes each were applied. For the control group, ordinary hospital care was applied. The data was collected before and 2 weeks after chemotherapy. Result: The scores of self-efficacy and self-care of the experimental group was higher than those of the control group while the state of anxiety of the experimental group was not lower than that of the control group at posttest. Conclusion: The self-efficacy promoting program about prevention of infection and hemorrhage increased cancer patients' self-efficacy and self-care but did not decrease anxiety. Further study is needed to find other factors to decrease anxiety and nurses need to consider the concept of self-efficacy in cancer patients receiving chemotherapy when they plan to increase cancer patients' self-care.

• Journal of Korean Home Economics Education Association
• /
• v.15 no.3
• /
• pp.59-73
• /
• 2003

This study aims to review and analyze the contents related to environment among curriculum of Technology$.$Home Economics subject; to produce multimedia learning materials and web-based materials for effective environmental education: and to find the way to effectively utilize them in schools. The data were analyzed by t-test with SPSS Win 10.0 program. The results of this study are as follows; First, the textbook carries a lot of contents concerning the environment. Second, the multimedia materials help students to understand environmental issues and strengthen their attitudes of environmental problems very effectively. Third, after using the instructional multimedia materials, the students showed significantly different results.

• Fire Science and Engineering
• /
• v.34 no.4
• /
• pp.29-35
• /
• 2020

This study was conducted to examine the performance in the space for a single alarm type detector installed in a single house. Three types of houses were used, including two types of one-story and two-story houses. A computer simulation program was used to predict the sound pressure level in response to the occurrence of an alarm sound in a residential space. The characteristics of the sound source applied to the simulation were directly measured and used as input data. As a result of simulation, it was found that the sound pressure level in the kitchen and living room generally met the standard when the alarm sound of the detector occurred. However, the sound pressure level in the bedroom was predicted to be at least 20 dB (A) lower than the American Fire Protection Association standard of 75 dB (A). Therefore, a plan should be prepared to maintain a sufficient sound level in the bedroom space inside the house, and efforts will be needed to ensure safe evacuation in case of fire by establishing relevant standards.

• 대한공업교육학회지
• /
• v.37 no.2
• /
• pp.161-179
• /
• 2012

The purpose of this study was to develop 'energy education' program for Creative Activities in middle school. The subject of this study was carried out with secondary student of middle school in Daegu. The development of 'energy education' program for middle school creative activies was carried out preparation, development and application. The details of each phase are as follows; The preparation phase was consised of collecting and research datas, energy education programs andliterature review for development of program. The development phase was developed through program that based on setting goals, designing of teaching-learning plans, development of materials of teaching and evaluation. The improvement phase was to modufy energy education instructional materials by running CD validity test of the expert, (2) preliminary tests and field trials of students. More than 65% of students to take class of this program agreed with the program of 'energy education' in class of creative activities was appropriate.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.1033-1036
• /
• 2013

A study about collision resolution is needed because huge file, video and multimedia information are transmitted to wireless LAN. CSMA/CR protocol guarantees fairness, but doesn't consider QoS. To practicalize CSMA/CR protocol in saturation fully-connected single hop network environments, this paper proposes method of collision compensation. previous CSMA/CR protocol chooses CR Slot only considering fairness, but this paper chooses front CR Slot for compensation of collision to station experiencing collisions. The station transmits jam signal and has channel priority of transmission. So transmitting efficiency and successful transmission probability rise. This proposed simple method can offer benefit to station experiencing collisions without additional hardware cost.

• Proceedings of the Korea Society of Mathematical Education Conference
• /
• 2006.04a
• /
• pp.25-37
• /
• 2006

영재를 위한 수학교육은 우리의 당면과제 중 하나이다. 능력 있는 학생들의 학습이 속진에 한정되는 것 보다는 심화자료 및 수학적 소프트웨어와 함께 하는 것이 더 의미 있을 것으로 기대된다. 본 연구는 스프레트쉬트를 사용한 수학적 아이디어의 탐구에 관한 것이다. 다음에 대해 논의하기로 하겠다. i) 스프레드쉬트는 비전통적이면서도 이용이 용이하며, 수학적 통찰을 위한 매개물이다. ii) 풍부하고, 흥미릅고, 가치있는 수학적 주제에 대해 스프레드쉬트를 이용할 수 있다. iii) 스프레드쉬트를 사용하여 학생들이 수학적 아이디어에 대한 흥미를 고취시킬 수 있다. iv) 스프레드쉬트는 학생들에게 그들의 창의적인 시각화 기술을 공개할 기회를 줌으로써 수학에 대한 폭넓은 도식적 이해를 제공한다. v) animation을 포함한 스프레드쉬트 도식들의 적절한 사용은 유익하면서도 흥미롭다. vi) 학생들은 일상생활에 나타나는 수학의 흥미로움을 발견할 것이다. vii) 교사는 지금의 지도방식에 스프레드쉬트를 통합할 수 있다. 특히 스프레드쉬트는 다음과 같은 면모도 가지고 있다. i) 창의적인 수학적 스프레드쉬트 모델들의 실제 과정들이 그 자체로써 수학적 개념발달에 이용될수 있다. ii) 스프레드쉬트 모델은 심화된 주제의 탐색을 위한 의미 있는 탐구과제를 제공한다. iii) 스프레드쉬트는 현장에서 사용되는 실제적 수학 도구이다. - 과학자나 공학도들의 사용도 증가되고 있다. 이것의 사용은 학생들이 현장에서 사용할 기술을 취득하게 할 수 있고, 같은 컴퓨터의 소프트웨어를 사용하는 가족의 대화 수단이 되기도 한다. 본 연구에서 우리는 스프레드쉬트의 4가지 실증적 예를 들어 보겠다. 또한 다른 영역에서 발전된 스프레드쉬트 모델의 몇 가지 도식적 산출물도 포함 할 것이다. 우리는 가장 대중적인 스프레드 쉬트인 Microsoft Excel 프로그램을 사용하였다. Excel의 수행과 Excel 연산의 설명을 담은 CD와 함께 다양한 사례들에 대한 논의는 (8)을 참고하기 바란다. 본고에서는 graphic animation 기술, 스크롤바의 사용을 간단하게 개괄하겠다. '동적형상들(movies)'를 만들 수 있는 간단한 매크로의 사용 등의 내용들은 각 자료를 사용할 수 있는 Excel 파일의 예와 함께 [1]과 [8]에 설명하였었다. 많은 인쇄물과 on-line 참고문헌, 매체자료들도 함께 제공하였다.