• Journal of Welding and Joining
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• 제7권4호
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• pp.30-37
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• 1989

Effect of heat treatment on mechanical properties of an overlay weldment was investigated. Over welding was carried out on the structural C-Mn mild steel substrate to take required test specimens. Shielded metal arc welding process with 13Cr-0.2Ni stick electrode was applied. The heat treatment temperatures and holding times were $450{\circ}C., 550{\circ}C., 650{\circ}C., 750{\circ}C., 850{\circ}C.$ and 0.5hr, 2hr, 10hr, respectively. Mechanical tests and microscopic inspection were also carried out to investigate welds soundness. Test results indicated that carbon migration was dominant near bonded zone. At temperature of around 650.deg. C, carburized layer and decarburized layer were formed remarkably along overlay welds region and C-Mn mild steel region, respectively. The wideth of these layers became wider with increasing heat treatment temperature and/or holding time at the elevated temperature, and this relationship agreed with Larson-Miller parameter. Side bending test results demonstrated that the crack free region of overlay welds could be deduced from the relationship between temperature and holding time.

• 보건의료산업학회지
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• 제3권1호
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• pp.66-77
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• 2009

This study was carried out to find out the of attitude and knowledge to blood donors in college and University students to provide basic data necessary for managing current blood donation system. The data were collected from 844 students from september 8 to 21, 2008 by using a self-administered questionnaire. The results were as follows: The major demographic characteristics were female 55.8% and the age group of 20-24s 60.5%, no religion 43.5%, blood type A 34.8% and so on. The major motivation for blood donation were to obtain a blood donation certificate to knowing necessary to blood donation 27.1%, take a voluntary service scored and souvenir 18.7%, and worthwhile and pride 9.9%. The experience the blood donation was 53.8%(male 69.2%, female 41.6%) of participants. Students who had more knowledge and desirable attitude about blood donation experienced more blood donations. It is important to clarify factors affecting blood donation practice and to encourage the public education and campaign which enable public has accurate knowledge and positive attitude about blood donation.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2010년도 학술대회 초록집
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• pp.27-27
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• 2010

There have been several studies about empirical relation between seismic source parameters(e.g., focal mechanisms, depths, magnitudes, etc.) and T-wave observation. In order to delineate the relation, numerical and theoretical approaches to figure out T-wave excitation mechanism are required. In an attempt to investigate source radiation and wave scattering effects in the oceanic crust on T-wave envelopes, we perform three-dimensional numerical modeling to synthesize T-wave envelopes. We first calculate seismic P- and SV-wave energy on the seafloor using the Direct Simulation Monte Carlo based on the Radiative Transfer Theory, which enables us to take into account both realistic seismic source parameters and wave scattering in heterogeneous media, and then estimate excited T-wave energy by normal mode computation. The numerical simulation has been carried out considering the following different conditions: source types (strike and normal faults), source depths (shallow and deep), and wave propagation through homogeneous and heterogeneous Earth media. From the results of numerical modeling, we confirmed that T-wave envelopes vary according to spatial seismic energy distributions on the seafloor for the various input parameters. Furthermore, the synthesized T-wave envelopes show directional patterns due to anisotropic source radiation, and the slope change of T-wave envelopes caused by focal depth. Seismic wave scattering in the oceanic crust is likely to control the shape of envelopes.

• 대한안전경영과학회지
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• 제14권4호
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• pp.125-136
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• 2012

In most child-care facilities, homeroom teachers take the responsibilities for safety education, which has been conducted in class hours on a regular basis. It was found that most homeroom teachers are lacking in teacher training opportunities, and the younger they are, the less training experience they get. Teachers with fewer teaching careers had a greater interest in safety education and training courses. In addition, homeroom teachers have been utilizing monthly toddler magazines as a method to acquire knowledges for safety education and prevention of safety accidents. The safety accidents which have most frequently occurred in care-care facilities turned out to be stumble and tear, and infants aged 3 years or younger were found to be easily exposed to the safety accidents mainly due to the frolic between peers during the free-choice activity time. The homeroom teachers recognized only traffic safety education among the range of safety training courses, which varied depending on teaching career such as traffic safety education and indoor/outdoor safety environment training, etc. In addition, it turned out that the safety training methods were limited to the utilization of discussion techniques, role-playing, description and demonstration.

• Architectural research
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• 제20권4호
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• pp.103-108
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• 2018

Wandering behavior is a serious problem among the elderly in nursing homes, yet it has received relatively little study As multi-family houses built before the '80s in South Korea were designed, it did not take account into issues related to parking so that at present parking became a big issue. The Seoul Metropolitan Government tried various ways to sort out the parking problem in multi-family house areas, but inadequate parking and illegal parking are still an ongoing problem. Thus, the purpose of this study was to examine current situation on resident parking only and illegal parking centered on a congested area of multi-family houses in Seoul and present the improvement plan of parking problems through case investigation home and abroad. As the result of the survey, it has been identified that the subject area consists of 506 households in total and 186 parking spaces and also, 100 cars in parking space or parking lot in housing space and 143 in illegal parking. Green parking business and open access parking system were suggested as solution plan for parking problem. Thus, it is expected that through green parking business for 6 houses and the parking lot of elementary schools around, the illegal parking problem would be sorted out.

• 한국해양공학회지
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• 제35권3호
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• pp.229-237
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• 2021

A numerical hydrodynamic performance analysis of the pitch-type multibody wave energy converter (WEC) is carried out based on both linear potential flow theory and computational fluid dynamics (CFD) in the unidirectional wave condition. In the present study, Salter's duck (rotor) is chosen for the analysis. The basic concept of the WEC rotor, which nods when the pressure-induced motions are in phase, is that it converts the kinetic and potential energies of the wave into rotational mechanical energy with the proper power-take-off system. This energy is converted to useful electric energy. The analysis is carried out using three WEC rotors. A multibody analysis using linear potential flow theory is performed using WAMIT (three-dimensional diffraction/radiation potential analysis program), and a CFD analysis is performed by placing three WEC rotors in a numerical wave tank. In particular, the spacing between the three rotors is set to 0.8, 1, and 1.2 times the rotor width, and the hydrodynamic interaction between adjacent rotors is checked. Finally, it is confirmed that the dynamic performance of the rotors slightly changes, but the difference due to the spacing is not noticeable. In addition, the CFD analysis shows a lateral flow phenomenon that cannot be confirmed by linear potential theory, and it is confirmed that the CFD analysis is necessary for the motion analysis of the rotor.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권6호
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• pp.1981-1995
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• 2021

When a person tries to conceal emotions, real emotions will manifest themselves in the form of micro-expressions. Research on facial micro-expression recognition is still extremely challenging in the field of pattern recognition. This is because it is difficult to implement the best feature extraction method to cope with micro-expressions with small changes and short duration. Most methods are based on hand-crafted features to extract subtle facial movements. In this study, we introduce a method that incorporates optical flow and deep learning. First, we take out the onset frame and the apex frame from each video sequence. Then, the motion features between these two frames are extracted using the optical flow method. Finally, the features are inputted into an improved MobileNetV2 model, where SVM is applied to classify expressions. In order to evaluate the effectiveness of the method, we conduct experiments on the public spontaneous micro-expression database CASME II. Under the condition of applying the leave-one-subject-out cross-validation method, the recognition accuracy rate reaches 53.01%, and the F-score reaches 0.5231. The results show that the proposed method can significantly improve the micro-expression recognition performance.

• 한국항행학회논문지
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• 제27권3호
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• pp.274-280
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• 2023

Fix-to-Fix 항법은 항공기 조종사가 항행 중 현재 지점에서 원하는 특정 지점으로 이동할 때 예상 Heading을 구하기 위해 사용하는 방법이다. 하지만 이 항법은 경험에 의한 주먹구구식 방법에 기반을 두고 있기 때문에 대략적인 방향만 알 수 있을 뿐 정확한 값을 알 수는 없다. 게다가 원하는 지점에 가까워져 Radial차가 작아져 HSI상의 Bearing Pointer와 Course Indicator가 인접하게 되면, 이 방법조차 사용하기 까다로워 예상 Heading은 더욱 구하기 어렵게 된다. 이러한 한계를 해결하기 위해 삼각함수의 극한을 Fix-to-Fix 항법에 도입하였다. 본 논문에서는 Fix-to-Fix 항법을 할 때 이러한 한계를 보완할 수 있는, 삼각함수의 극한을 활용한 두 가지 방법을 제시하고 그 오차를 분석하였다.

• 이베로아메리카
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• 제12권2호
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• pp.383-428
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• 2010

To make a critical revision on the inherited social problems throughout the time in Mexico, not always turns out to be easy task, especially when the subject is lent to approach it from diverse perspective, one of them, the educative one. To analyze the low quality of the educative supply is complex subject. One of the maximum profits of institutional revolutionary Mexico was the creation of the Public Education Ministry in 1921. In the post-revolutionary and modern period, the seventies were characterized to be applied to the growth the infrastructure and the fortification of the educative system following the policy of "modernization and development". From the eighties, to lift the quality of the education was considered like one of the specific rules in the strategy of the call "educative revolution". In the nineties, through political programs and agreements, structural changes within the educative system were carried out with the intention to lift the quality of the services. In synthesis, the perspective in the educative policy of Mexico during the last thirty years of century xx, or post-revolutionary period, can be understood, from at least five specific conditions: educative profits in cover, modifications in the educational programs and contents, profits in the political agreements between the agents who take part within the educative system, changes and modifications to the laws applicable to the education, and; the search of the fairness through the compensatory programs. This paper tries to give answer to questions such as: The educative system reflects the ideals of the revolution? The present educative system is the product of a truncated revolution or the fruit of an untimely democracy?

• 영어영문학
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• 제58권6호
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• pp.1085-1101
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• 2012

This study, guided by Engeström's (1999, 2001) activity theory which owes its theoretical lineage to sociocultural theory, explores how roles (peer feedback givers and receivers) and tasks are distributed among EFL students who engage in peer response. More specifically, as an extension of previous research of focusing on "stances" ESL students adopt, I investigate whether different roles in peer response groups make a difference in the nature of peer response and identify what underlays the different roles in peer group interaction. In addition, I examine whether different roles to the peer response create tensions and contradictions in peer response and how these created conflicts lead to changes in peer response activity system. The data I wish to consider is first-person narratives elicited from two EFL college students. I use Won's and Choi's (both pseudonyms) stories as a heuristic, which is a method that allowing one to proceed fruitfully in finding information. Foregrounded in this study are the students' different roles in the same peer response activity. A division of labor exists between Won/Choi and their peers - the way tasks are divided up and the way roles are structured. Yet Won and Choi adopted rather divergent roles when participating in peer response activity and carried out qualitatively different peer response activities. It is obvious here that the distribution of their roles in carrying out this particular peer response is shaped by Won' and Choi's perception about the validity of their peers' responses.