• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.31-37
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• 2021

As the size of buildings increases due to urbanization due to the development of industry, the need to purify the air and maintain a comfortable indoor environment is also increasing. With the development of monitoring technology for refrigeration systems, it has become possible to manage the amount of electricity consumed in buildings. In particular, refrigeration systems account for about 40% of power consumption in commercial buildings. Therefore, in order to develop the refrigeration system failure diagnosis algorithm in this study, the purpose of this study was to understand the structure of the refrigeration system, collect and analyze data generated during the operation of the refrigeration system, and quickly detect and classify failure situations with various types and severity . In particular, in order to improve the classification accuracy of failure types that are difficult to classify, a three-step diagnosis and classification algorithm was developed and proposed. A model based on SVM and LGBM was presented as a classification model suitable for each stage after a number of experiments and hyper-parameter optimization process. In this study, the characteristics affecting failure were preserved as much as possible, and all failure types, including refrigerant-related failures, which had been difficult in previous studies, were derived with excellent results.

• Journal of the Korean GEO-environmental Society
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• v.21 no.8
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• pp.5-13
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• 2020

During the construction of underground space expansion of old facilities, it is necessary to secure temporary residence space for existing residents as well as noise and vibration issues during construction, and in the case of commercial, industrial, and social use, damage is expected from suspension of the use of facilities. There is a need for a technology that minimizes noise and vibration during underground expansion, enabling the use of existing facilities even during construction. In this study, a practical underground extension model is proposed by analyzing the behavior of the temporary structure and the surrounding ground as a result of measurement at each construction stage for a actual construction site. In order to solve the problems that occurred during construction, the basement slabs were placed in advance after the initial excavation. The measurement results (building inclinometer, crack measurement system, structure inclinometer and surface settlement meter) at the site were reviewed to analyze the behavior of the temporary structure and surrounding ground. As a result, it was confirmed that the inclinometer of the building and the structural inclinometer showed a tendency that the displacement after the slab line was placed was reduced or converged. The placement of basement slabs during underground extension not only relived the noise and vibration problems during construction, but also secured the stability of structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.2
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• pp.109-116
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• 2007

The purpose of this paper is to evaluate the fire resistant performances of load-bearing wall using both composite and steel stud panel infilled with light-weight formed mortar under axial loading according to KS F 2257(1999). The minimum requirement of 2 hours fire resistant rating is needed for the residential and commercial buildings under the fire regulation of Korea. From test results, it is found that two types of specimen composed of the hybrid stud and steel stud panel filled with light-weight formed mortar fited in with the requirement of 2 hours fire resisting rate for the load-bearing wall. In the conclusions, the specimen with hybrid stud shows predominating fire-resistant performance on the adiabatic effects rather than that of the steel stud specimen.

• The Journal of the Korea Contents Association
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• v.8 no.8
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• pp.285-292
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• 2008

This study was initiated to evaluate the Phosphorus(P) leaching potential in the putting green soils and P uptake by the turfgrass in the golf course using the P fertilizers. The turfgrass, Floradwarf bermudagrass(Cynodon dactylon L. PERS,) was planted and grown in the mixture of sand and peat moss in this lysimeter study. Five representative P fertilizers, such as, ammonium polyphosphate (APP), monopotassium phosphate (MKP), MAP(monoammonium phosphate), 0-20-20(liquid), and concentrated superphosphate(CSP, solid) were used in this study. Based on the total P quantity of leachate collected during the whole 12 weeks, MKP and APP are the first group of P fertilizers contributing to the leaching of P, then MAP and 0-20-20 are the second group of P fertilizers causing the P leaching. Finally, CSP is the third group of P fertilizer resulting in the P leaching. However, most of P applied and collected in the lysimeter were leached during the first period of two and four weeks, compared to that of P leached during the second period of six, eight, ten, and twelve weeks. Applications of MAP, APP and CSP, MKP and 0-20-20 in order produced the largest amount of total dry matter. However, APP, MKP and MAP, CSP and 0-20-20 in order showed the largest amount of P uptake. Therefore, based on the data of P leaching, dry matter production, and plant P uptake, it appears that CSP, 0-20-20, and MAP are the environmentally sound fertilizers recommended in the turfgrass putting green soil of golf course.

• The Journal of the Korea Contents Association
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• v.13 no.1
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• pp.456-466
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• 2013

The most important thing to develop real estate asset would be a feasibility study. To secure feasibility of development projects, reducing and minimizing the cost of land and construction also would be the important thing. To analyze optimal land-value for real estate development projects, I have collected 204 balance sheets of development projects in South Korea. With the help of statistical technology, I could have selected useful data from those balance sheets. After detailed analysis of statistical data, I could have reached conclusion that the most important factor to earning rate would be land cost per unit ground area under the constraint of given sale price. So far the main pattern of feasibility study of development projects was land cost and construction cost. However, by this study, I have found a new fact that construction cost has little effect to earning rate and land cost per unit ground area is the most effect to earning rate especially in residential facilities rather than commercial ones.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.1006-1009
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• 2015

Power-line communication technology is proposed to identify power transformers to serve customers in 3 phase -4 wires power distribution systems. Mathematical models for 3-phase power transformers, 3-phase wire lines, and customer loads are described to investigate the transmission characteristics of high frequency power line carrier. From the analysis, distribution line cable circuits have only a limited ability to carry higher frequencies. Typically power transformers in the distribution system prevent propagating the higher frequency carrier signal. The proposed method uses the limited propagation ability to identify the power transformer to serve customers. A novel power transformer identification system is designed and implemented. The system consists of a transmitter and a receiver with power-line communication module. Some experiments are conducted to verify the theoretical concepts in a big commercial building. Also some simulations are done to help and understand the concepts by using MATLAB Simulink simulator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3213-3219
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• 2014

Currently, increase of greenhouse gas has had a signigicant impact on climate change in urbanization. As a result, the government has been looking for ways to take advantage of the trees that generate oxygen and reduce carbon dioxide for the prevention of climate change. It is essential to extract individual tree for calculating the amount of carbon dioxide reduction of trees. Aerial LIDAR data have three-dimensional information of building as well as trees as form of point clouds. In this study, automated model was developed to extract individual tree using aerial LIDAR data. For this purpose, we established a methodology for extracting trees and then proceeded the process of developing it as an automated model based on model builder of ArcGIS Software. In order to evaluate the applicability of the developed model, the model was compared with commercial software in study area located in Yongin City. Through the experimental result, the proposed model was extract trees 9.91% higher than commercial software. From this results, it was found that the model effectively extracted trees.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.2
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• pp.8-15
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• 2006

To reduce costs and address other practical concern related to architectural lighting, we have been involved in various aspects of advanced daylighting design and control. If we look toward future building trends, we see that the advanced has already successfully deployed such complex lighting control systems. This paper takes a broad view of what advanced manufacturers have done to develop energy efficient lighting control technologies such as sensors, lumen maintenance, time of day scheduling, peak demand reduction and so forth. First of all strategies, daylighting controls would also need to be commissioned to respond to the specific daylighting signature of the zone. To translate the daylight in term of the amount of energy savings, an electric lighting system is designed and automatic on-off control system integrated with the contribution of daylighting has been applied to the operating of the artificial lighting. The lighting analysis program, Lumen-Micro predicts the optimal layout of conventional fluorescent and incandescent lighting fixtures to meet the designed lighting level and calculates unit power density, which translates the demanded amount of lighting energy.

• Korean Journal of Food Science and Technology
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• v.34 no.1
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• pp.96-102
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• 2002

The levels of biologically active compounds, such as isoflavone, total saponin, dietary fiber, soy oligosaccharides, and lecithin from each serving size of commercial soy products, were quantitatively determined from the raw soybean, soymilk, tofu, isolated soy protein (ISP), soybean paste(toenjang), natto, and tempeh from local and foreign market. Soy flour, natto, and soymilk contained 489.1 mg, 308.3 mg, and 138.1 mg of isoflavone in each 100 g of dry matter, respectively. The ratios of aglycone to glucoside of soybean paste and tempeh showed relatively high level compared with other tested soy products. Commercial soymilk showed the highest ratio of soluble fiber to total dietary(59%). The higher levels of dietary fiber (20.1 g) and lecithin (1.13 g) were also found in tofu. The lecithin and saponin content of isolated soy protein(ISP) were highest (0.63 g and 0.65 g/ 100 g of dry matter) among the tested samples. In conclusion, soy flour showed the highest level of biologically active compounds, such as saponin, isoflavone, dietary fiber, and soy oligosaccharides. But when the evaluation was based on the serving size, soymilk containing 31.5 mg of isoflavone, 2.59 g of dietary fiber, 0.57 g of oligosaccharides, 0.10 g of lecithin, and 0.11 g of saponin showed similarity to those of the tested soybeans(20 g).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.559-562
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• 2017

In city, tracing of power transmission lines is difficult due to compound installation of overhead and underground lines, transposition, bad view caused by trees or big buildings. It is hard problem for electrical technician on site to trace power transformers or power lines to serve customers in 3 phase -4 wires power distribution systems. It is necessary that the correct and fast tracing method is required for load balancing among distribution lines. Old technology use to trace off-lines with high power impulse injection. Our proposed method use to trace live lines with very small power high frequency signal injection. Typical power transformers in the distribution system prevent propagating the higher frequency carrier signal. The proposed method uses the limited propagation ability to identify the power transformer to serve customers. Two end communication terminals are required to be synchronized between them for determination on electrically same phases. Challenging issue is to achieve synchronization without GPS providing synchronizing time. A novel power transformer and wire identification system is designed and implemented. The system consists of a transmitter and a receiver with power-line communication module. Some experiments are conducted to verify the theoretical concepts in a big commercial building. Also some simulations are done to help and understand the concepts by using MATLAB Simulink simulator.