• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.39 no.1
• /
• pp.64-72
• /
• 2016

In this paper, we utilize a Gaussian process to predict the power consumption in the air-conditioning system. As the power consumption in the air-conditioning system takes a form of a time-series and the prediction of the power consumption becomes very important from the perspective of the efficient energy management, it is worth to investigate the time-series model for the prediction of the power consumption. To this end, we apply the Gaussian process to predict the power consumption, in which the Gaussian process provides a prior probability to every possible function and higher probabilities are given to functions that are more likely consistent with the empirical data. We also discuss how to estimate the hyper-parameters, which are parameters in the covariance function of the Gaussian process model. We estimated the hyper-parameters with two different methods (marginal likelihood and leave-one-out cross validation) and obtained a model that pertinently describes the data and the results are more or less independent of the estimation method of hyper-parameters. We validated the prediction results by the error analysis of the mean relative error and the mean absolute error. The mean relative error analysis showed that about 3.4% of the predicted value came from the error, and the mean absolute error analysis confirmed that the error in within the standard deviation of the predicted value. We also adopt the non-parametric Wilcoxon's sign-rank test to assess the fitness of the proposed model and found that the null hypothesis of uniformity was accepted under the significance level of 5%. These results can be applied to a more elaborate control of the power consumption in the air-conditioning system.

• Korean Journal of Construction Engineering and Management
• /
• v.19 no.3
• /
• pp.43-51
• /
• 2018

Facility Management (FM) phase in building lifecycle management is the most crucial phase concerning building value and life cycle cost management. Nevertheless, systematic and rational FM process is not yet constructed, leading to failure of facility value and cost management from accurate and proactive FM. This is because there has been minimal approach regarding construction of optimal FM process based on rational FM data analysis. The purpose of this study is to provide optimal FM process with quantitative FM data analysis method using spatial data. This study investigated existing FM data structure and derive the limitation of it from both expert interview and practical FM material analysis. As a solution for this limitation, this study provided optimal FM process with MTBF (Mean Time Between Failure), which is quantitative FM data analysis method. The effect of the provided process was validated with a case study. It is expected that this process allows rational and objective FM data analysis, resulting in accurate and proactive FM. And it is expected that it can be used as a useful basic data for developing an effective system for the FM process.

• Journal of Korean Society for Atmospheric Environment
• /
• v.33 no.5
• /
• pp.521-528
• /
• 2017

In the combustion treatment of explosive gases with a high heating value such as $H_2$ and $NH_3$ used in semiconductor and chemical processes, the heat recovery modeling and exergy analysis of the process using the Aspen Plus simulator and its thermodynamic data were performed to examine the recovery of high temperature thermal energy. The heat recovery process was analyzed through this process modeling while the exergy results clearly confirmed that the rigorous reaction mainly occurs in the condenser and the chamber. In addition, the process modeling demonstrated that approximately 95% of the exergy is destructed on the basis of the exergies injected and the exergy being exhausted. Using the exergy technique, which can quantitatively analyze the energy, we could understand the energy flow in the process and confirm that our heat recovery process was efficiently designed.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.33 no.3
• /
• pp.201-206
• /
• 2009

The focus of this work is placed on the analysis of the mixture formation process under the evaporative diesel-free spray conditions. In order to examine homogeneity of mixture within the vapor phase region of the injected spray, image analysis was carried out based on the entropy of statistical thermodynamics. As an experimental parameter, the injection pressure and ambient gas density were selected, and effects of the injection pressure and density variation of ambient gas on the mixture formation process in the evaporative diesel spray were investigated. In the case of application of the thermodynamic entropy analysis to evaporative diesel spray, the value of the dimensionless entropy always increases with increase in time from injection start. Consequently, the dimensionless entropy in the case of the higher injection pressure is higher than that of lower injection pressure during initial injection period.

• Journal of Technology Innovation
• /
• v.13 no.1
• /
• pp.73-89
• /
• 2005

As a scientific educational facility, the role of science museum has been enlarged. However there are few study to evaluate the public value of science museum. This paper applies a conjoint analysis to measuring the public value of science museum. At first, this paper chose the attributes of science museum and derived the marginal willingness to pay, As a result, the choice works for selecting a preferred option among three alternatives were within respondents' ability and the derived marginal willingness-to-pay estimates were statistically different from zero. This paper contributes to complementing the existing valuation methods by estimating the attributes of science museum and providing policy-makers with useful methodological framework and quantitative information in the decision-making process related to the policy of cultural facilities.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.26 no.7
• /
• pp.946-957
• /
• 2002

Amicable brand relationships between consumers and brands are connected with consumers' positive attitude and strong attachment to the brands; therefore, it is necessary to examine the factors which affect consumers in forming brand relationships. Through theoretical review, two variables, brand association and brand communication, were manifested as important factors in building brand relationships. The purposes of this study were to identify the different types of brand association, and to examine the influence of brand association and brand communication on brand relationships. The survey which focused on ten casual wear brands and 739 young female students was conducted from August 20 to September 12, 2000. Spss 8.0 was used for factor analysis and regression analysis. Brand association was further delineated into brand value association and brand personality association and each variable consisted of several factors. Both performance value and emotional value among brand value association factors and both pride and sincerity among brand personality association factors showed goons influence on building brand relationship. Brand communication showed significant influence on brand relationship directly and indirectly.

• International Journal of Advanced Culture Technology
• /
• v.7 no.2
• /
• pp.34-41
• /
• 2019

The purpose of this study was to examine the meaning and structure of the experience of female college students. For this purpose, 22 female college students, regardless of age, participated in the interview three times in total. Interview data were processed through the analysis and interpretation process using the phenomenological research method, Giorgi method. As a result, 34 semantic units were derived, then divided into 14 subcomponents, and then divided into 6 categories. As a result of analysis, the spiritual value of female college students was composed of "family", "friendly person", "professional person", "empathy", "reflection" and "trust". Based on the above meaning, the structure of the spiritual value of female college students can conclude that they were a continuation of life that forms a strong sense of value and empathy and trust with patience with family and friends. Based on this, intervention on spiritual well-being of female college students suggests that intervention to form values based on empathy and trust based on family and close friends is implemented.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.38 no.4
• /
• pp.39-44
• /
• 2015

The VHTR (Very High Temperature gas-cooled nuclear Reactor) has been considered as a major heat source and the most safe generation IV type reactor for mass hydrogen production to prepare for the hydrogen economy era. The VHTR satisfies goals for the GIF (Generation IV International Forum) policy such as sustainablility, economics, reliability and proliferation resistance and physical protection, and safety. As a part of a VHTR economic analysis, we have studied the VHTR construction cost and operation and maintenance cost. However, it is somewhat difficult to expect the ripple effect on the whole industry due to the lack of information about Inter-industries relationship. In many case, the ripple effect are based on experts' knowledge or uncertain qualitative assumptions. As a result, we propose quantitative analysis techniques for ripple effects such as the production inducement effect, added value inducement effect, and employment inducement effect for VHTR 600MWt${\times}$4 modules construction and operation ripple effect based on NOAK (Nth Of A Kind). Because inducement effect values have been published annually, we predict inducement effect's relation function and estimated values including production inducement effect value, added value inducement effect value, and employment inducement effect value using time series and estimated values are verified with published inducement effects' value. This paper presents a new method for the ripple effect and preliminary ripple effect consequence using a time series analysis and inter-industry table. This ripple effect analysis techniques can be applied to effect expectation analysis as well as other type reactor's ripple effect analysis including VHTR for process heat.

• Tribology and Lubricants
• /
• v.19 no.1
• /
• pp.1-8
• /
• 2003

Recently, PM-high speed steel(PM-HSS) has reportedly been a good alternative material for rolling mill because of its superior performance to conventional HSS. This paper has been aimed to investigate the possibility for application to rolling contact element for PM-HSS by X-ray diffraction technique. The X-ray elastic constant for PH-HSS has been found by X-ray diffraction during the four-point bending test. Residual stress and half-value breadth on the contact surface during rolling contact fatigue process by X-ray diffraction have also been measured. The result of this study shows that the application of X-ray diffraction technique to PM-HSS could be as possible alternative material as conventional HSS. Half-value breadth on rolling contact surface by X-ray diffraction is not changed during rolling contact fatigue process. On the other hand, the residual stress is changed. This suggests that dislocation reaction has been hardly occurred in rolling contact, depending on super-saturated carbon in PM-HSS.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.10 no.5
• /
• pp.26-30
• /
• 2011

Currently, many researches are carried out about tilting index table, which is one of the main component of 5-axis machine tool. The performance of the tilting index table is associated the rotational accuracy which is very important factor for high precision machining because it have an effect on machining error. In this paper, a tilting index table is developed, and the rotational accuracy of the tilting index table using a laser measurement equipment is measured. In addition, a correction value is obtained from the measured value through compensation, and the correction value is used to improve the accuracy of the table. Comparative analysis is carried out for the accuracy of the table before and after compensation. This paper can be used by a reference for performance and reliability advancement of tilting index table.