• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.833-841
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• 2021

During the postulated severe accident of nuclear reactor, eutectic reaction leads to low-temperature melting of fuel cladding and early failure of core structure. In order to model eutectic melting with the moving particle semi-implicit (MPS) method, the eutectic reaction model is developed to simulate the eutectic reaction phenomenon. The coupling of mass diffusion and phase diagram is applied to calculate the eutectic reaction with the uniform temperature. A heat transfer formula is proposed based on the phase diagram to handle the heat release or absorption during the process of eutectic reaction, and it can combine with mass diffusion and phase diagram to describe the eutectic reaction with temperature variation. The heat transfer formula is verified by the one-dimensional melting simulations and the predicted interface position agrees well with the theoretical solution. In order to verify the eutectic reaction models, the eutectic reaction of uranium and iron in two semi-infinite domains is simulated, and the profile of solid thickness decrease over time follows the parabolic law. The modified MPS method is applied to calculate Transient Reactor Test Facility (TREAT) experiment, the penetration rate in the simulations are agreeable with the experiment results. In addition, a hypothetical case based on the TREAT experiment is also conducted to validate the eutectic reaction with temperature variation, the results present continuity with the simulations of TREAT experiment. Thus the improved method is proved to be capable of simulating the eutectic reaction in the severe accident.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.167-175
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• 2019

Recently, health examination centers have been changing from auxiliary medical facilities to key and independent medical facilities. However, it is not easy to improve medical facilities, including health examination centers, due to the variable characteristics of the relationship between humans and space. Therefore, this study was done to develop a pedestrian-based discrete event simulation analysis program to examine the problems and develop methods for improvement. The program was developed to analyze five evaluation indices and the density of examinees. The problems were derived by analyzing the required time, capacity, and queue size for each examination through simulations. We reduced the examination time and moving distance, increased the capacity, and distributed the queues by adjusting the medical services and relocating the examination rooms. The results were then quantitatively verified by simulations.

• Fire Science and Engineering
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• v.32 no.6
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• pp.40-45
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• 2018

The omnidirectional surveillance camera uses the object detection algorithm to level the object by unit so that broadband surveillance can be performed using a fisheye lens and then, it was a field experiment with a system composed of an omnidirectional surveillance camera and a tracking (PTZ) camera. The omnidirectional surveillance camera accurately detects the moving object, displays the squarely, and tracks it in close cooperation with the tracking camera. In the field test of flame detection and temperature of the sensing camera, when the flame is detected during the auto scan, the detection camera stops and the temperature is displayed by moving the corresponding spot part to the central part of the screen. It is also possible to measure the distance of the flame from the distance of 1.5 km, which exceeds the standard of calorific value of 1 km 2,340 kcal. In the performance test of detecting the flame along the distance, it is possible to be 1.5 km in width exceeding $56cm{\times}90cm$ at a distance of 1km, and so it is also adaptable to forest fire. The system is expected to be very useful for safety such as prevention of intrinsic or surrounding fire and intrusion monitoring if it is installed in a petroleum gas storage facility or a storing place for oil in the future.

• Journal of Bio-Environment Control
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• v.31 no.1
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• pp.52-59
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• 2022

Pest control treatment was carried out using an unmanned automatic pesticide spraying system that can spray pesticides on crops while moving autonomously to control pests in vegetable greenhouse. As a result of examining the control effect on tomato and strawberry on thrips (Frankliniella occidentalis) and greenhouse whitefly (Trialeurodes vaporariorum) pests, 85.6% of yellow flower thrips were found in tomatoes and 87.5% in strawberries, and 81.7% (tomato) and 80.6% (strawberry) of greenhouse whitefly. In addition, the control effect according to the pesticide treatment method showed a control effect of 81.7% of the chemical spraying treatment by manpower and 83.9% of the automatic moving pesticide spraying treatment (F=22.1, p < 0.001). When comparing the control effect between the two treatment sections, there was no significance, but the automatic transfer spraying treatment showed a 2.2% higher effect. On the other hand, as a result of comparing the spraying time of the drug, the automatic unmanned control sprayer had a spraying time of 5 min/10a, which took about 25 min less than the conventional manpower spraying time of 25-30 min/10a. Based on these results, it was judged that the automatic transfer spraying method could be usefully used for efficient pest control in the facility greenhouse during the peak period of development.

• Journal of National Security and Military Science
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• s.1
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• pp.155-190
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• 2003

The objective of this study is to provide basic information for planning and practicing social welfare services for married nurse officers serving in the Korean military. For such a purpose, this study identifies the difficulties which married nurse officers have faced and the necessary services which are supposed to alleviate them. The data were collected by sending a questionnaire to 114 married nurse officers from July 16 to August 10, 2001. The results of this study are as follows: First, the married nurse officers were relatively dissatisfied with such domains as child care and education, health, and housing. And among the thirty-four problems, the married nurse officers expressed the most serious dissatisfaction with the difficulty in attending the events held in child's school, lack of children's dormitory run by the military, difficulty in adjusting to the school due to frequent house-moving, and limited access to dental care. Second, the married nurse officers needed services in domains such as housing, child care and education, and health. Specifically, they wanted the military-run housing, child care facility within military hospitals, maternity leave for child care and education, extension of risk allowances, and support for BOQ. Third, with regard to the seriousness of problems as well as the priority of services, the married nurse officers gave higher priority to such domains as child care and education, health, and housing. These results indicate that married nurse officers were to the largest extent concerned with these three domains and that they had the urgent need for services relevant to those domains. The importance of routine need assessments as well as solutions to the family-related problems for married nurse officers is therefore suggested in this study.

• Korean Journal of Computational Design and Engineering
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• v.15 no.3
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• pp.212-221
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• 2010

Proposed in the paper is a methodology to generate kinematic template for 3D JIG models. Recently, according to increase of the rate of automatic facility in manufacturing system, the 3D manufacturing and verification research and development have been issued. So, unlike in the past, moving 3D facilities are very various like JIGs, turn table, AS/RS worked in the automated manufacturing industry. Because 3D mesh models are used in these kinds of 3D simulation, users have to define the kinematic information manually. This 3D mesh data doesn't have parametric information and design history of the 3D model unlike the design level data. So, it is lighter than 3D design level data and more efficient to render on the 3D virtual manufacturing environment. But, when user wants to find a common axis located between the links, the parameter information of the model has to reconstruct for defining kinematic construction. It takes a long time and very repetitive to define an axis and makes a joint using 3D mesh data and it is non-intuitive task for user. This paper proposed template model that provides kinematic information of the JIG. This model is kinds of a state diagram to describe a relation between links. So, this model can be used for a kinematic template to the JIG which has a same mechanism. The template model has to be registered in the template library to use in the future, after user made the model of the specific type of the 3D JIG model.

• Journal of Animal Environmental Science
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• v.13 no.2
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• pp.121-128
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• 2007

To develop the composting system to reduce the use of bulking agent, continuous composting was performed with farmer scale facility, The plant comprises a horizontal pit reactor closed inside a greenhouse and equipped with a turning machine moving on rails. The pit was 9m wide and 50m long and the maximum height of loaded materials was $1.8m^2$. The materials remained in the reactor for 5 months. During the composting process, temperature and water content measured and water balance was evaluated. The reaction temperature of composting was changed $30{\sim}50^{\circ}C$ and high in the middle and low in under composting piles. The moisture contents of the compost were approximately 70% during the experiment. The amount of effluent was 10.6% and $3.16m^3$ of pig slurry per $1m^3$ of bulking agent was treated during continuous composting process. BOD and SS reduction of the effluent in continuous composting was 86.5% and 92.2%, respectively. Indoor relative humidity in night time was changed between 80 and 100%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.3
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• pp.479-486
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• 2002

In this study, the progressive inelastic deformation, so called, thermal ratchet phenomenon which can occur in high temperature structures of liquid metal reactor was simulated with thermal ratchet structural test facility and 316L stainless steel test cylinder. The thermal ratchet deformation at the reactor baffle cylinder of the liquid metal reactor can occur due to the moving temperature distribution along the axial direction as the sodium free surface moves up and down under the cyclic heat-up and cool-down transients. The ratchet deformation was measured with the laser displacement sensor and LVDTs after cooling the structural specimen which is heated up to 55$0^{\circ}C$ with steep temperature gradients along the axial direction. The temperature distribution of the test cylinder along the axial direction was measured with 28 channels of thermocouples and was used for the ratchet analysis. The thermal ratchet deformation was analyzed with the constitutive equation of nonlinear combined hardening model which was implemented as ABAQUS user subroutine and the analysis results were compared with those of the test. Thermal ratchet load was applied 9 times and the residual displacement after 9 cycles of thermal load was measured to be 1.79mm. The ratcheting deformation shapes obtained by the analysis with the combined hardening model were in reasonable agreement with those of the structural tests.

• Korean Institute of Interior Design Journal
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• v.19 no.6
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• pp.224-232
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• 2010

This paper aims to identify the characteristics and the current situation of the architectural characteristics, children's characters using facilities, and status of management and utilization by surveying 'Day Service for Children' in Tokyo-do. First, About the status of management and utilization, 'Day Service for Children' is operated by a local government, NPO corporate group and social welfare corporate. There are not big differences of the care program or running hours depending on operating principals but there are differences depending on staff organization, number of children and space constitution. Also, infants ratio at 'Day Service for Children' is high for the purpose of detecting disability early and supporting their development early. They have diverse disabilities but developmental disabilities' ratios high and most children are using both this facility and normal nursery centers together. Samples for proper child care based on status of space constitutions were installing lock, raising door knobs and using softer floor materials which are for children's safety. For the problem of space utilization, most comments were about lack of space which is not enough for teaching and training materials. Therefore, as an example, observation rooms for parents and teachers were sometimes used as storages and it changes teachers' moving direction, staying area and behavior zone. The programs of 'Day Service for Children' are divided to group teaching and private one. It will be the best if they have separate spaces such as group class room, private class room and play room. When they were operated by NPO corporate group or Social welfare corporate, there are many cases that their space was not properly zoned for each activity.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.3
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• pp.68-79
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• 2008

Ground vehicle borne system which is named RoSSAV(Road Safety Survey and Analysis Vehicle) developed in KICT(Korea Institute of Construction Technology) can collect road geometric data. This system therefore is able to evaluate the road safety and analyze road deficient sections using data collected along the roads. The purpose of this study is to extract road geometric data for 3D road modeling in dangerous road section and The system should be able to quickly provide more accurate data. Various sensors(circular laser scanner, GPS, INS, CCD camera and DMI) are installed in moving object and collect road environment data. Finally, We extract 3d road geometry(center, boundary), road facility and slope using integrated multi-sensor data.