• 전기학회논문지
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• 제57권5호
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• pp.797-802
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• 2008

High Speed Rail Train Control System consists of CTC, IXL and ATC. IXL and ATC perform train control and command via interchanging relevant information between a signal room and CTC. However, it is proved that IXL and ATC are attributed to train delay error since those systems are highly sensitive to trackside conditions. Especially, network error on IXL blocks transmitting signal information to adjacent signal room so that its effects give rise to system overall problems. In order to figure out the measures for which minimizing the occurrence rate of train delay error due to HSR TCS, This paper is performed analysis on communication network structure, the length of SSI network roof and SSI-TFM distance by examining and analyzing the error cases related to IXL in a network aspect.

• Earthquakes and Structures
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• 제4권3호
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• pp.285-297
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• 2013

The effect of soil structure interaction (SSI) on seismic response of a multi-degree-of-freedom structure isolated with a friction pendulum system (FPS) is studied. In the analysis, the soil is considered as an elastic continuum and is modeled using the finite element method. The effect of SSI on response of the structure is evaluated for twenty far-field and twenty near-fault earthquake ground motions. The effect of friction coefficient of sliding material of FPS on SSI is also studied. The results of the study show that the seismic response of the structure increases for majority of the earthquake ground motions due to SSI. The sliding displacement and base shear are underestimated if SSI effects are ignored in the seismic analysis of structures isolated with FPS.

• Earthquakes and Structures
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• 제25권2호
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• pp.79-87
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• 2023

Special moment resisting steel frame structures are now being used commonly in highly seismic regions as seismically reliable structures. However, a very important parameter describing the dynamics of steel structures during earthquake loading, Soil Structure Interaction (SSI), is generally neglected. In this study, the significance of consideration of flexibility of soil in being able to obtain a result closer to reality is asserted. The current paper focuses on calculation of seismic fragility curves special moment resisting steel frame structures under different earthquake loadings for fixed-base and SSI models. The observation of obtained fragility curves lead to the conclusion that the SSI has a considerable effect on component fragility for the steel structures, with its effects decreasing for higher peak ground acceleration. The results show that the structures when considered SSI have a higher probability of exceeding a damage limit state. This observation attests the role of SSI in the accurate study of structural performance.

• 공학교육연구
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• 제23권3호
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• pp.3-12
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• 2020

This study explores the effects of an SSI-based program focused on character and values for engineering college students. The participants were fifty-four students enrolled in the program. Data sources include the students' responses to the Likert-type questionnaire on character and values as well as qualitative data such as classroom dialogues, assignment essays and field notes. The results indicate that the program significantly contributed to the enhancement of the engineering college students' perception of character and values, especially in the sub-components, sustainable development, perspective-taking, and willingness to act. In addition, the qualitative data reveals the nuances of the students' responses in the classroom dialogue and essays related to the sub-components. Based on the results, the author compares the participants' responses to other students in previous research which reported the effects of an SSI-based program on character and values. Compared to the other students, the engineering students in this study cultivated willingness to act through the SSI-based program, without improvement in most of the emotional aspects of character and values.

• Structural Engineering and Mechanics
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• 제76권2호
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• pp.223-237
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• 2020

Transmission towers have come to represent one of the most important infrastructures in today's society, which may suffer severe earthquakes during their service lives. However, in the conventional seismic analyses of transmission towers, the towers are normally assumed to be fixed on the ground without considering the effect of soil-structure interaction (SSI) on the pile-supported transmission tower. This assumption may lead to inaccurate seismic performance estimations of transmission towers. In the present study, the seismic response and failure analyses of pile-supported transmission towers considering SSI are comprehensively performed based on the finite element method. Specifically, two detailed finite element (FE) models of the employed pile-supported transmission tower with and without consideration of SSI effects are established in ABAQUS analysis platform, in which SSI is simulated by the classical p-y approach. A simulation method is developed to stochastically synthesize the earthquake ground motions at different soil depths (i.e. depth-varying ground motions, DVGMs). The impacts of SSI on the dynamic characteristic, seismic response and failure modes are investigated and discussed by using the generated FE models and ground motions. Numerical results show that the vibration mode shapes of the pile-supported transmission towers with and without SSI are basically same; however, SSI can significantly affect the dynamic characteristic by altering the vibration frequencies of different modes. Neglecting the SSI and the variability of earthquake motions at different depths may cause an underestimate and overestimate on the seismic responses, respectively. Moreover, the seismic failure mode of pile-supported transmission towers is also significantly impacted by the SSI and DVGMs.

• 한국과학교육학회지
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• 제35권3호
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• pp.431-442
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• 2015

본 연구에서는 '집단지성 촉진 전략을 활용한 SSI 수업모형(CI기반 SSI 수업모형)'을 중학교 영재학급 학생들을 대상으로 적용하여 그 효과를 탐색해 보았다. 특히, 집단지성의 원리를 적용했을 때 더욱 향상될 것으로 기대되는 역량 즉, 협업능력, 정보 기술 및 미디어 활용능력, 비판적 사고력과 문제 해결력, 의사소통 능력에 초점을 맞추어 살펴보았다. 또한 학생들이 CI기반 SSI 수업모형에 적용된 집단지성의 원리의 효과를 어떻게 인식하는지도 함께 살펴보았다. 본 연구는 서울에 위치한 중학교 영재학급 학생 20명을 대상으로 하였으며, 이 학생들은 약 1년에 걸쳐 토요일마다 격주로 수업에 참여하였다. 학생들은 과학기술 사회에서 요구되는 시민역량 검사지에 수업 전, 중간, 후에 응답하였으며, 수업이 진행되는 동안 수업관찰 및 학생들과의 그룹면담을 실시하였다. 연구결과, CI기반 SSI 수업은 학생들의 과학기술 사회 시민으로서 갖추어야 할 핵심 역량의 여러 요소들이 향상될 수 있는 가능성을 보여주었다. 비록 통계적으로 유의미한 차이는 아니었으나, 수업 및 면담자료에 대한 추가 분석은 이 가능성에 대해 어느 정도 뒷받침해주었다. 첫째, 학생들은 웹 플랫폼을 활용하여 조원들과 활발하게 정보공유를 함으로써 생각의 확장을 경험하였다. 둘째, 학생들은 수업에 참여하면서 다양한 관점에 대한 포용력이 다소 향상되었다. 셋째, 학생들은 토의주제에 대해 미리 자료를 수집하고 스스로 독립적인 시간을 가짐으로써 조별 토의에 보다 적극적으로 참여하게 되었으며, 조원간의 소통도 더 원활해졌다고 응답하였다. 마지막으로, 학생들은 협업의 가치에 대해 인지하게 되고, 협업을 통해 더 나은 산출물을 낼 수 있다는 경험을 하게 되었다.

• Journal of Preventive Medicine and Public Health
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• 제30권2호
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• pp.392-401
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• 1997

Generally working environment and worker's health status of small scale industries (SSI) which employ less than 50 workers are known to be poorer than those of large scale industries(LSI) which employ more than 500 workers. However, according to the analysis of occupational injuries in Korea, prevalence rate of occupational injuries of SSI was 3.1 times as high as LSI. But there was no difference in prevalence rate of occupational disease and werkers with suspected occupational disease(D1) between SSI and LSI. To confirm these two different facts, we surveyed working environment and worker's health status of SSI and LSI in Kyeungin industrial complex. Workers in SSI were 10,878 and workers in LSI were 8,291 and number of hazardous agents in SSI were 3,554 and those of LSI were 1,916. We found following results. First, proportion of male workers and workers who were less than 30 yens old and more than 50 yens old was higher in SSI compared to LSI. Second, worker in SSI had more liver disease, viral hepatitis, and pneumoconiosis than in LSI, and there were more worker with suspected occupational disease, general disease, and worker needed close observation in SSI. But these effects had not statistical significance under the condition controlled by age and sex with logistic regression. Third, the numbers measured for specific chemicals, organic solvents, and heavy metals in SSI was more than in LSI. However there was on difference in the excess rate of each hazardous agent between SSI and LSI. As the above results workers' health status in SSI was poorer than in LSI, but these results were mainly due to the population structure difference. Although there were some limitation of this study and problems of sensitivity and validity for periodic health examination and working environment evaluation method, the concept that working environment and worker's health status in SSI should be reviewed. In future the study that will reveal the real weak point of SSI should be performed.

• 대한지구과학교육학회지
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• 제7권3호
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• pp.338-346
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• 2014

In this study, find out of recognition of the effect of science, society and ethical aspects on natural disasters and understanding degree of knowledge applying for SSI class aimed at elementary pre-service teachers by developing SSI training program of the 'Earth and Space' field. Also, after SSI class application we examined the change perceptions of elementary pre-service teachers. SSI training program was that elementary pre-service teachers participated in the SSI class of a variety of subjects in the field of 'Earth and Space' and directly joined in the decision-making process and reflectional discussion with colleagues as conducted in this class reflective discussion with the pre-primary teachers pre-service teachers. Elementary pre-service teachers were understanding of the nature of the science and to understand in more depth about the SSI class characteristics. This study, second grade 115 people who was taking 'science and teaching materials' course in B National University of Education at B city participated. In order to apply for SSI class, one semester based on 15 weeks until seven weeks were science and teaching materials and based on the nature of science, after 8 weeks we set the theme of the contents related to the Earth and space and give lesson applied for SSI. During 8 weeks, test subjects 4 classes were taking 50 minutes a week 100 minutes. First time has theoretical lessons in topics related to the 'Earth and space' and on the second week, each classes participate in the decision-making processes respectivly by dicussing and debating on the first week's topic as regarding social and moral aspects of it. We obtained the following results. First, elementary pre-service teachers were acquiring the results of 67% in the knowledge aspects of the 'Earth and space'. This result was determined that most of the elementary pre-service teachers were liberal arts in high school. Second, while participating in the SSI class, elementary pre-service teachers were concretely aware of the nature of SSI and the characteristics of the class. Third, the elementary pre-service teacher are thaught that introduction education courses about 'Earth and space' are needed but most of the students responded that this would require a lot of effort of teachers. This was derived from not familiar class form that did not fulfill in the science teaching methods until now.

• Earthquakes and Structures
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• 제13권6호
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• pp.561-572
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• 2017

Seismic base isolation has been accepted as one of the most popular design procedures to protect important structures against earthquakes. However, due to lack of information and experimental data the application of base isolation is quite limited to nuclear power plant (NPP) industry. Moreover, the effects of inelastic behavior of soil beneath base-isolated NPP have raised questions to the effectiveness of isolation device. This study applies the wavelet analysis to investigate the effects of soil-structure interaction (SSI) on the seismic response of a base-isolated NPP structure. To evaluate the SSI effects, the NPP structure is modelled as a lumped mass stick model and combined with a soil model using the concept of cone models. The lead rubber bearing (LRB) base isolator is used to adopt the base isolation system. The shear wave velocity of soil is varied to reflect the real rock site conditions of structure. The comparison between seismic performance of isolated structure and non-isolated structure has drawn. The results show that the wavelet analysis proves to be an efficient tool to evaluate the SSI effects on the seismic response of base-isolated structure and the seismic performance of base-isolated NPP is not sensitive to the effects in this case.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.337-344
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• 2006

This paper is concerned with the simplified criterion given in ASCE 4-98, for determining whether soil-structure interaction (SSI) analysis is required for seismic response analysis of nuclear power plant structures. In this study, the criterion is evaluated for a couple of example structures including an existing nuclear power plant and the Hualien large-scale seismic test building. Forced vibration analysis and seismic response analysis are carried out using the simple stick model with soil springs and an elaborated SSI analytical model. From the numerical analyses, it is found that the criterion may not allow the fixed-base analysis for bedrock with shear wave velocity of greater than 1,100m/s which is a well-known criterion for a rock site. In addition, it is indicated that peak amplification as well as the peak broadening specified in NRC RG 1.122. shall be considered to include the effects of SSI.