• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.616-622
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• 2016

The heating load using solar hot water is lower in summer than in the other seasons. This decreased heating load leads to the overheating solar collectors and related components. To prevent overheating of the solar collectors, air cooling and shading shields were used. On the other hand, it requires additional mechanical components, and reduces the system reliability. The geothermal heat dump system to release the high temperature heat (over $150^{\circ}C$) transferred from the heat pipe solar collectors was investigated in the present study. Research on the heat dump to cool the solar collector is rare. Therefore, the present study was carried out to collect possible data of a geothermal heat dump to cool the solar collector. A helical type geothermal heat exchanger was buried at a 1.2m depth. Experimentally and numerically, the geothermal heat dump was investigated in terms of the effects of parameters, such as the quantity of solar radiation, aperture area of the collector and the mass flow rate. A pipe length of 50m on the geothermal heat exchanger was suitable with a 0.33 kg/s flow rate. The water reservoir was a possible co-operation solution linked to the geothermal heat exchanger.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2221-2231
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• 2017

In this paper, we surveyed previous cases, network protocols (such as Wi-Fi, Zigbee, Z-wave, and WirelessHart) and propagation characteristics on the application of maintaining equipments for instrumentation and control (I&C) using wireless communication techniques inside the nuclear power plant (NPP). In addition, we compared and analyzed the difference of detailed regulations with respect to the electromagnetic interference (EMI) and radio frequency interference (RFI) in the Regulatory Guide 1.180 rev. 1 (RG. 1.180) for adopting the wireless communication techniques inside the NPP, and other regulations, such as MIL-STD 461E and IEC 61000-4, that are recognized in the KINS/RG-N03.09 (Rev. 2). Furthermore, we investigated evaluating factors about electromagnetic properties by considering indoor environments, wave scattering, shielding effectiveness, and the indoor wave attenuation model that were not included in the current electromagnetic compatibility regulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.22-30
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• 2017

This paper presents the research results of a light weight through topology optimization and structural safety evaluation through structural analysis of a pressure system structure installed in an off-shore plant. Conducting a structure design according to the wind load and the dynamic load at sea in addition to a self-load and structure stability evaluation are very important for structures installed in off-shore plants. In this study, the wind and dynamic load conditions according to the DNV classification rule was applied to the analysis. The topology optimization method was applied to the structure to obtain a lightweight shape. Phase optimization analysis confirmed the stress concentration portion. Topology optimization analysis takes the shape by removing unnecessary elements in the design that have been designed to form a rib shape. Based on the analysis results about the light weight optimal shape, a safety evaluation through structural analysis and suitability of the shape was conducted. This study suggests a design and safety evaluation of an off-shore plant structure that is difficult for structural safety evaluations using an actual test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.694-702
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• 2017

In the case of an elevated railway station, structure borne noise and vibration due to structural limitations allow the load and vibration from railway vehicles to be directly transmitted to the station structure, resulting in an increase in the number of civil complaints from customers and staff of the station. The floating slab track system, which is well known as one of the solutions for reducing the noise and vibration from elevated railway stations, usually contains rubber mounts or rubber pads under the railway slab which act as a damper. These types of device have the disadvantage that is difficult to predetermine the exact stiffness and damping ratio under the nonlinear loads resulting from train services. In this study, an isolator with a friction type of wedge is introduced, which can be applied to floating slab track systems and to be designed with precisely the required stiffness. Furthermore, a comparative analysis of the stiffness between the designed and experimental values is carried out, while the damping ratio, which is closely related to the friction wedge blocks, is deduced according to the train load condition. The performance tests of the isolator were conducted in accordance with the DIN 45673-7 standard which includes both static and dynamic load tests. The load conditions for the performance tests are designed to conform to the DIN standard related to the weight of the train and rail track, in order to perform vertical and horizontal load tests, so as to ensure the secure structural safety of the railway. Also, by checking the change aspect of the friction coefficients of the friction elements according to the loading rate, the vibration reduction performance of the friction type isolator with variable loading rate conditions is examined.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.3
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• pp.113-122
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• 2007

The rapid growth of aerial survey and remote sensing technology has enabled the rapid acquisition of very large amounts of geographic data, which should be analyzed using real-time visualization technology. The level of detail(LOD) algorithm is one of the most important elements for realizing real-time visualization. We chose the triangulated irregular network (TIN) method to generate normalized digital elevation model(DEM) data. First, we generated TIN data using contour lines obtained from a two-dimensional(2D) digital map and created a 2D grid array fitting the size of the area. Then, we generated normalized DEM data by calculating the intersection points between the TIN data and the points on the 2D grid array. We used constrained Delaunay triangulation(CDT) and ray-triangle intersection algorithms to calculate the intersection points between the TIN data and the points on the 2D grid array in each step. In addition, we simulated a three-dimensional(3D) terrain model based on normalized DEM data with real-time visualization using a Microsoft Visual C++ 6.0 program in the DirectX API library and a quad-tree LOD algorithm.

• Clean Technology
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• v.23 no.1
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• pp.42-53
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• 2017

Numerical analysis was done to evaluate the fluid distribution inside of the mixing quencher to increase the reaction efficiency of the aqueous hydrogen peroxide solution in the scrubbing column which is used for simultaneous desulfurization and denitrification. Effective injection of the aqueous hydrogen peroxide ($H_2O_2$) solution in the mixing quencher has major effects for improving the reaction efficiency in the scrubbing column by enhancing the mixing of the aqueous $H_2O_2$ solution with the exhaust gas. The current study is to optimize the array of nozzles and the spray angles of the aqueous $H_2O_2$ solution in the mixing quencher by using the computational method. Main concerns of the analysis are how to enhance the uniformity of the $H_2O_2$ concentration distribution in the internal flow. Numerical analysis was done to check the distribution of the internal flow in the mixing quencher in terms of RMS values of the $H_2O_2$ concentration at the end of quencher. The concentration distribution of $H_2O_2$ at the end of is evaluated with respect to the different array of the nozzle pipes and the nozzle tip angles, and we also analyzed the turbulence formation and fluid mixing in the zone. The effect of the spray angle was evaluated with respect to the mixing efficiency in different flow directions. The optimized mixing quencher had the nozzle array at location of 0.3 m from the inlet duct surface and the spray angle is $15^{\circ}$ with the co-current flow. The RMS value of the $H_2O_2$ concentration at the end of the mixing quencher was 12.4%.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.1
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• pp.28-42
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• 2009

In the wake of categorizing the design changes occurred during the period from 2004 till the first half of 2006 in Choongcheong province area, based on purpose and reason of design changes identified by the Korea National Housing Corp, it included 11 types such as the image of the apartment complex, scenic elements, consideration by the user, prevention of the defect, constructability, site conditions, incompatibility between the activities, superordinate standard, prevention of civic complaints, design details and others, along with 47 subordinate elements. And the evaluation intended to identify the corelation between the number and time of design change approval, frequency and scale of design change by type and the cost variations indicated that; firstly, enhancing the image of the apartment complex proved to be the main reason for design changes, accounting for 22% in terms of frequency and 54.9% in terms of cost variation. Secondly, the higher the increase in cost by design change aimed at improving the image of the complex, the lower the decrease in cost by design change for uncertain reasons, dubbed the inverse proportional relations, indicating that the design changes for uncertain reasons were mostly aimed at reducing the construction cost. Thirdly, with regard to the number of design change approval and the time of the initial approval, twice or less and 90 days or less before completion of the construction work, respectively, accounted for $52{\sim}53%$, indicating the design change deliberation and approval tended to have been carried out collectively in the form of ex post facto approval, which seemed to be attributable to the attempt of reducing the construction cost or budget problem, as a result of comparing with the cases in which the cost was reduced.

• Information Systems Review
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• v.18 no.1
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• pp.79-103
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• 2016

The Korean Army has to construct a system that will enable it to cope immediately with the flexible military relationships in Northeast Asia by systematizing and improving the efficiency of operations. These improvements include building a smart and strong army, concentrating on cost-effective combat skills, maximizing the utilization of private resources, and establishing a military structure based on information and technology. Accordingly, this study proposes solutions to solve the problems affecting the success of outsourcing in the defense industry. Unlike outsourcing in other government ministries, outsourcing in the national defense sector may be unrealistic because this strategy is related to the renovation project of the Ministry of the National Defense. In general, the objective of outsourcing in the defense industry, similar to other businesses, is to improve efficiency and not to reduce troops and national defense budget. Several factors, such as identification and security guarantee, risk reduction, cost saving, quality improvement, the reliability of enterprise, and professional technology, are necessary to ensure outsourcing success in the national defense sector. In terms of effectiveness, the improvement in service quality significantly influences outsourcing success in the national defense sector. Eventually, the national defense forces must be strengthened to prevent the provocative actions of North Korea and other threats by improving identification, sense of national security, and quality unlike the current outsourcing of the government, as well as emulating German GEBB or PMC, which utilizes social capital.

• Therapeutic Science for Rehabilitation
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• v.1 no.1
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• pp.29-38
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• 2012

Introduction : This study reviews the main areas of cognitive rehabilitation including executive dysfunction, memory dysfunction, perceptual dysfunction, attention deficit, and dysfunctions in activities of daily living in order to apply to the adaptation of occupational therapy. Body : Cognition programs based on the virtual reality are being used not only to evaluate but to train the overall components of human's cognition. Because the cognitive program is concentrating on the real environment, it is known to bring a remarkable transitional effect to the actual environment, compared to the basic computer-based evaluation and training. Applying virtual reality to the rehabilitation program can develop and advance the high technology and can result in a major effect on the innovative treatment technology. Conclusions : In this process, virtual reality is expected to be researched more in the near future. Particularly in the cognitive realm, it is imperative for researchers to pay attention to the improved transitional effect of the virtual reality toward the actual environment, rather than the already existing method of evaluations. Therefore, application of the virtual reality for the cognitive training should be researched for various types of subjects in the diverse aspects of congnitive function. Application of the virtual reality in the cognitive function has its unlimited potential, thus the rehabilitation program integrated with not only evaluation but training and education is expected extensively in the future.

• Journal of the Korean Applied Science and Technology
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• v.35 no.2
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• pp.412-422
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• 2018

The purpose of this study was to investigate effects of 12-weeks aerobic exercise and taekwondo exercise on brain wave activation and brain-derived neurotrophic factors in undergraduate male students. Twenty four male subjects participated in this study. They were separated into a Control group(CG; n=8), Aerobic training group (ATG; n=8) and Taekwondo training group(TTG; n=8). ATG and TTG participated in Aerobic exercise training and Taekwondo exercise training for 12 weeks, 50~80 minutes per day, 3 times a week at 60~80% HRR respectively. All data were analyzed by repeated measures two-way ANOVA. As a result, there were no significant differences in the body composition and brain activation in all groups. However BDNF increased significantly after 12 weeks in the aerobic training groups(ATG). It is suggest that 12 weeks of regular Taekwondo exercise training did not statistically affect brain activation and neurotrophic factors in undergraduate students.