• International conference on construction engineering and project management
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• 2011.02a
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• pp.213-220
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• 2011

In the current construction industry where various stakeholders take part, BIM Data exchange using standard format can provide a more efficient working environment for related staffs during the life-cycle of the building. Currently, the formats used to exchange the data from 3D-CAD application to structure energy analysis at the design stages are IFC, the international standard format provided by IAI, and gbXML, developed by Autodesk. However, because of insufficient data compatibility, the BIM data produced in the 3D-CAD application cannot be directly used in the energy analysis, thus there needs to be additional data entry. The reasons for this are as follows: First, an IFC file cannot contain all the data required for energy simulation. Second, architects sometimes write material names on the drawings that are not matching to those in the standard material library used in energy analysis tools. DOE-2.2 and Energy Plus are the most popular energy analysis engines. And both engines have their own material libraries. However, our investigation revealed that the two libraries are not compatible. First, the types and unit of properties were different. Second, material names used in the library and the codes of the materials were different. Furthermore, there is no material library in Korean language. Thus, by comparing the basic library of DOE-2, the most commonly used energy analysis engine worldwide, and EnergyPlus regarding construction materials; this study will analyze the material data required for energy analysis and propose a way to effectively enter these using semantic web's ontology. This study is meaningful as it enhances the objective credibility of the analysis result when analyzing the energy, and as a conceptual study on the usage of ontology in the construction industry.

• Korean Journal of Construction Engineering and Management
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• v.17 no.2
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• pp.31-38
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• 2016

In a construction project, the portion for maintenance costs for a building is considerable compared to the initial construction cost. As such, Life Cycle Cost (LCC) analysis is being increasingly utilized to assess the design value of engineering work in Korea. Additionally, the Public Procurement Service in Korea announced that it will be mandatory for all domestic construction projects to adopt BIM. Furthermore, the paradigm for architectural design has shifted from 2D to 3D, and to BIM, which includes a data management system. Within this background, however, there is currently no adequate BIM-based LCC analysis software and the requirements of cost estimation for repair and replacement cost for a building is not completely adequate in BIM tools such as Revit and Archicad. Therefore, this study suggests a process of cost estimation for repair and replacement (R&R) cost based on IFC data. First, we analyzed existing R&R criteria and defined BIM-based requirements when calculating R&R costs. These requirements were extracted from relevant IFC data. Subsequently, this was saved to a database and a BIM-based database was built for R&R cost estimation. Finally, this database was connected with external databases such as R&R Criteria DB and Cost Information DB to calculate R&R costs. This process is expected to improve upon the traditional process of cost estimation of R&R cost by applying a BIM model. The proposed process can contribute to a further standardizing of BIM-based LCC analysis thru application to initial construction costs, energy costs, and other maintenance costs.

• Journal of environmental and Sanitary engineering
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• v.22 no.4
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• pp.45-54
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• 2007

With the rapid development of economy, scientific technology, and medical technology, as the current society is also changing competitively, we are compelled to have many psychological and problems such as pressure, mental stress and tension as well as physical problems. Therefore, the more current industries develops, the more attention is given to health in preventive level rather than treatment level. Contemporary people have paid more attention to management of health and have a desire for beautiful and healthy life. In other words, their interest in consistent management of their health and beauty are getting stronger. To satisfy the desire to live healthily and beautifully, many natural therapies that can be applied for actual living have been developed, which the public are willing to accept. Therefore, this study is to specifically demonstrate the followings through interviews with the customers who have armoatherapy: What effect customers' knowledge on aromatherapy, frequency of use, expenses, experiences of side-effects, and perception on its effect on skin care will have on customer satisfaction and intention to reuse the service. The results are presented as follows: Though customers' perception on aroma is high, they usually use it only on their faces. So is should be promoted in various ways. It is demonstrated that customers' satisfaction has a significant effect on their intention to reuse it.

• Journal of Korean Society of Rural Planning
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• v.13 no.3
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• pp.23-32
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• 2007

In Korea, a regulation of visual impact evaluation on development plan in natural environment is provided at the Natural Environment Conservation Act, but it was difficult to obtained the effectiveness enough to conserve natural landscape. So, the visual impact review on development plan is introduced to the act, through the revision of the Natural Environment Conservation Act in 2005. The basic directions of visual impact review are preservation, restoration, view protection, and harmony. The items of review are as follows; (1) development alternations for the provided plan, (2) executive reduction plan of visual impacts including consideration of growth of plants, (3) deliberation process between persons or parties concerned, etc. For rapid settlement of visual impact review system, it needs that the validity, the reliability, and the objectivity should be confirmed through steady research about reasonable guidance of review.

• Journal of Korean Society for Quality Management
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• v.39 no.4
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• pp.507-515
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• 2011

MIL-HDBK-217 has played a pivotal role in reliability prediction of electronic equipments for more than 30 years. Recently, RIAC developed a new methodology $217Plus^{TM}$which officially replaces MIL-HDBK-217. Sensitivity analysis of the 217Plus component models to various parameters has been performed and meaningful observations have been drawn in this study. We first briefly reviewed the $217Plus^{TM}$ methodolog and compared it with the conventional model, MIL-HDBK-217. We then performed sensitivity analysis $217Plus^{TM}$ component models to various parameters. Based on the six parameters and an orthogonal array selected, we have performed indepth analyses concerning parameter effects on the model. Our result indicates that, among various parameters, operating temperature and temperature rise during operation have the most significant impacts on the life of a component, and thus a design robust to high temperature is the most importantly required. Next, year of manufacture, duty cycle, and voltage stress are weaker but may be significant when they are in heavy load conditions. Although our study is restricted to a specific type of diodes, the results are still valid to other cases. The results in this study not only figure out the behavior of the predicted failure rate as a function of parameters but provide meaningful guidelines for practical applications.

• Journal of Korean Society for Quality Management
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• v.41 no.1
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• pp.135-148
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• 2013

Purpose: This paper presents a method to evaluate the stockpile reliability of propelling charge for performance and storage safety with storage time. Methods: We consider a performance failure level is the amount of muzzle velocity drop which is the maximum allowed standard deviation multiplied by 6. The lifetime for performance is estimated by non-linear regression analysis. The state failure level is assumed that the content of stabilizer is below 0.2%. Because the degradation of stabilizer with storage time has both distribution of state and distribution of lifetime, it must be evaluated by stochastic process method such as gamma process. Results: It is estimated that the lifetime for performance is 59 years. The state distribution at each storage time can be shown from probability density function of degradation. It is estimated that the average lifetime as $B_{50}$ life is 33 years from cumulative failure distribution function curve. Conclusion: The lifetime for storage safety is shorter than for performance and we must consider both the lifetime for storage safety and the lifetime performance because of variation of degradation rate.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1605-1611
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• 2017

In this study, the characteristic lifetime of power facilities such as power transformers and GIS were investigated as the basis of power facility asset management. It is difficult to obtain the operation and failure data of the facilities in Korea. Therefore, the number of failures of the electric power facilities was calculated from the operation data and hazard rate shown in the overseas literatures, and the statistical analysis was performed using the Weibull distribution function. As a result of extracting and analyzing the data of the UK National Grid for power transformers, the characteristic lifetime (scale parameter) of 116.45 years was considered to be a very appropriate value for power transformer management and can be used as a comparative data of the analysis of the domestic transformers. As for the GIS, based on the Bays and Bay-Years data and the hazard rate according to the operation years of the 123kV GIS in Germany, it is found out that the characteristic lifetime of GIS is not so meaningful. It is necessary to decide a maintenance strategy and lifetime expectancy considering the characteristics of the design, materials and manufacturing process of GIS.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.4
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• pp.327-332
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• 2019

Recently, inverter control systems have attracted immense attention to increase the energy efficiency. However, such systems use repeated on/off high currents for linear operation control, instead of the prevalent step variable current control method. Hence, there arise concerns of personal and property damage, especially due to the durability, explosive characteristics, and operating speed of the fuse, which is responsible for safety and is one of the internal components using current control. Therefore, in this paper, we propose an IEC60127-4 SMD sub-miniature fuse, consisting of Ag-Cu alloys and ceramic powder for arc soothing. The IEC60127-4 SMD sub-miniature fuse has high durability and cut-off capacity, and operates safely in dangerous circumstances caused by the inverter control system.

• Journal of Engineering Education Research
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• v.11 no.1
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• pp.64-75
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• 2008

A new product development and product realization process (PRP) is a circulating and feedback process by generating ideas through creative problem solving process. The early stages of PRP correspond to conceptual design and product development, in which a large portion of product life cycle cost can be saved. The optimal design method for this stage is a robust design suggested by Taguchi. Quality must be 'engineered in' since it can not be 'inspected out.' A robust design is an engineering methodology to improve the quality of a product by minimizing the efforts of variations without eliminating the causes. The objective of this study is to propose a scheme and a case study of robust design for exploring design parameters, and introduce a creative problem solving process. Major research subjects include a creative problem solving process, robust design procedure and their implementation. For the experiment of Taguchi method, a toy catapult is adopted. For the creativity development, a short project is assigned to devise a similar tool with the toy catapult. A reference model is suggested to compare and evaluate their ideas.

• Korean Journal of Construction Engineering and Management
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• v.14 no.4
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• pp.35-45
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• 2013

Facility Management is the longest in the building of life cycle. Because it occupies more than 80% of cost, the phase of Facility Management has to be managed and has to be perceived as important as design and construction phase. The method to manage building more efficiently is the introduction of Facility Management System used by CAD and database. But information Requirement is now input by hand in the most Facility Management System. This study aims to analyze the example of applying BIM in the Korea or abroad and the errors of this were deducted by many phase. Lastly, the possible solution is suggested in order to be used in the Facility Management System. This study's benchmarking is COBIE which is developed by the COE(Corps of Engineers) and now popular in the world. The suggestion in this study is the method that I have already mentioned is helpful for a designer to do modeling when a designer uses BIM S/W(software). To be more specific, the method plays a side role in helping data input considering the phase of Facility Management.