• Geomechanics and Engineering
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• v.7 no.5
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• pp.495-524
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• 2014

To investigate the soil-pile interactive performance under lateral loads, a set of laboratory model tests was conducted on remoulded test bed of soft clay and medium dense sand. Then, a simplified boundary element analysis had been carried out assuming floating pile. In case of soft clay, it has been observed that lateral loads on piles can initiate the formation of a gap, soil heave and the tension crack in the vicinity of the soil surface and the interface, whereas in medium dense sand, a semi-elliptical depression zone can develop. Comparison of test and boundary element results indicates the accuracy of the solution developed. However, in the boundary element analysis, the possible shear stresses likely to be developed at the interface are ignored in order to simplify the existing complex equations. Moreover, it is unable to capture the influence of base restraint in case of a socketed pile. To bridge up this gap and to study the influence of the initial stress state and interface parameters, a field based case-study of laterally-loaded pile in layered soil with socketed tip is explored and modelled using the finite element method. The results of the model have been verified against known field measurements from a case-study. Parametric studies have been conducted to investigate the influence of the coefficient of lateral earth pressure and the interface strength reduction factor on the results of the model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1519-1526
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• 2013

This study reviewed the capturing performance of a canopy hood used in some melting processes of a casting manufacturing factory through a site survey. In addition, this study compared and evaluated the flow field and pressure field for the plans to enhance the hazardous air pollutants collection capacity by using CFD model. The case-2(flange attached + double hood) can be improved in terms of collection performance, but is expected to increase in hood static pressure by about 70% more than the existing structure, so it was shown that its site applicability is not good. It is judged that the shape of case-3(flange attached + double cone attached) is most suitable to improve the suction efficiency. This is because a double cone is installed at the center of the opening to concentrate the flow rate on the edge of the hood and control the hume rising to the center of the hood without a static pressure rise via the slope of the cone.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.281-281
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• 2014

The field emission properties of GaN are reported in the present study. To be a good field emitter, it requires a low work function, high aspect ratio, and strong mechanical stability. In the case of GaN, it has a quite low work function (4.1eV) and strong chemical/mechanical/thermal stabilities. However, so far, it was difficult to fabricate vertical GaN nanostructures with a high aspect ratio. In this study, we successfully achieved vertically well aligned GaN nanostructures with chemical vapor-phase etching methods [1] (Fig. 1). In this method, we chemically etched the GaN film using hydrogen chloride and ammonia gases at high temperature around $900^{\circ}C$. This process effectively forms vertical nanostructures without patterning procedure. This favorable shape of GaN nanostructures for electron emitting results in excellent field emission properties such as a low turn-on field and long term stability. In addition, we observed a uniform fluorescence image from a phosphor film attached at the anode part. The turn-on field for the GaN nanostructures is found to be about $0.8V/{\mu}m$ at current density of $20{\mu}A$/cm^2. This value is even lower than that of typical carbon nanotubes ($1V/{\mu}m$). Moreover, threshold field is $1.8V/{\mu}m$ at current density of $1mA$/cm^2. The GaN nanostructures achieved a high current density within a small applied field range. We believe that our chemically etched vertical nanostructures are the promising structures for various field emitting devices.

• Journal of Families and Better Life
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• v.33 no.4
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• pp.51-65
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• 2015

Case management is becoming increasingly more important in the field of social welfare. The purpose of this study was to examine the practice of case management at community child centers and to identify factors influencing their performance. In addition, this study also analysed the performance level of case management at each stage and the factors influencing the level at each stage. For the purpose of this study, data obtained from about 181 community child center workers in Busan, Ulsan and Gyeongsangnamdo were analyzed. According to the results of the analysis, in Model 1 which represents the category of socio-demographic and personal factors, three factors namely gender, experience in case management, and interpersonal skills were found to be significantly influential and they have an explanatory power of 21.5%. Under the category of organizational factors in Model 2, four factors were found to be influential: experience in case management, interpersonal skills, availability of case management guidelines, and holding case conferences. These factors account for 33% explanatory power, 11.5% higher than that of Model 1. In Model 3 which represents the third category of community network literacy, three factors namely interpersonal skills, availability of case management guidelines, and ability to utilize networks were found to influence case management at community child centers, and they have an explanatory power of 43.4%, 10.4% higher than that of Model 2. For the practice of social welfare, these findings have the implication that community child center workers need to improve their interpersonal skills by cultivating communication skills, collaborative problem-solving skills, conflict-management skills, and other relevant skills. Furthermore, it is necessary to provide specific guidelines for case management, to have regular case conferences, to establish a community network, and to reinforce cooperation and mutual support among institutions within the network.

• Journal of Korean Society for Quality Management
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• v.31 no.1
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• pp.90-108
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• 2003

This study deals with a case analysis on the implementation of ISO 9000/14000 Integrated Management System. The intention is to provide some general guidelines, in particular, to small-to-medium-sized companies that are planning to introduce the Integrated Management System. First we briefly review each of the ISO 9000 series, ISO 14000 series and Integrated Management System. We then investigate the case of a small-sized company that have built and is successfully operating the Integrated Management System. We start with introducing the company, and then examine the background and the procedure for implementing the Integrated Management System. We investigate effects of the Integrated Management System, which are the main focus of this paper. This study is meaningful in that, to our best knowledge, it is the first field report appearing in the literature in regard to the actual implementation of ISO 9000/14000 Integrated Management System in Korea.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.4
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• pp.25-31
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• 2009

In development phase of the Aircraft Systems, the reliability prediction of electronic equipments are usually performed using MIL-HDBK-217. The reliability of fielded electronic systems, however, used to be underestimated with MIL-HDBK-217. To solve this problem, some alternatives are suggested and Telcordia SR-332 is among them. In this case study, the reliability of ESU which controls gas turbine engine is predicted using Telcordia SR-332 along with the development test data. The predicted reliabilities of ESU using Telcordia SR-332 and MIL-HDBK-217 are also compared. As a result this case study showed that the predicted reliability using Telcordia SR-332 was better close to field(operation) reliability than MIL-HDBK-217.

• Journal of Hydrogen and New Energy
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• v.33 no.6
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• pp.674-683
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• 2022

In this study, we examined the case of Fukushima Hydrogen Research Field (FH2R) Namie hydrogen town. We found that the case has three aspects of socio-technical experiment: a living-scale test-bed of hydrogen technologies, activities for enhancing social acceptability, and a designed module for policy transfer to diffuse. This study aims to provide a benchmark for planning a green hydrogen city in near future.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.599-602
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• 2003

The objective of this study is to analyze the function of the paddy-field in purifying water quality. This study was carried out is based on the data in the six case studies. To improve purification function of paddy field, the following farming management is required. 1) A guideline to control the inlet and outlet of the paddy plot is need to minimize drainage water by means of a reasonable irrigation management. 2) A guideline for fertilizer application in consideration of loading nutrients dissolved in irrigation water. 3) The reuse system of agricultural drainage water is required to minimize impacts on water quality of surface water(reservoir and river).

• Journal of the Korean housing association
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• v.26 no.1
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• pp.19-30
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• 2015

As the number of homeless is increasing, there have been worries for social burden and social insecurity, along with crisis in human dignity. The purpose of this research is to identify characteristics of a Supportive Housing (SH) project which is considered best practice in dealing with homeless problem. A field visit walk through observation and in-depth interview was utilized as the main research method. As results, overall management, spatial and service characteristics were delineated, and its meaning and uniqueness were discussed, as well as, comparison with Korean conditions. In conclusion, the characteristics of the Supportive Housing were more realistically revealed through a current field case to inspire to explore housing for Korea. Besides current concerns were linked and implication to Korean adaptation was suggested. This study is unique in that SH of USA is firstly introduced in such details.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1156-1163
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• 2010

The bi-directional high pile load test(BDH PLT) does not have weaknesses found in the existing bi-directional low pile load test(BDL PLT); it has strong economics, is unbound by load capacity limit and secures quality stability of working piles. In this study, Verification the field found a very high capacity level of stability and reliability of the BDH PLT, as well as outstanding field applicability. Field verifications reaffirmed the advantage of the BDH PLT device, which was capable of loading 90 MN capacities as maximum. It was also found to be durable enough to load high capacity with ease.