• Journal of the Korean Operations Research and Management Science Society
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• v.16 no.1
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• pp.45-58
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• 1991

The importance of marketing mix variables, replacement demand, and competition in a new product growth model has been cited by many researchers. In this paper, these factors are integrated with an aim to model company sales of competing durables. Based on the most popular new product growth model, numerous extensions and incorporations of contributions from related research fields are tried. Model parameters are estimated by the Kalman filter. And, the proposed model is applied to the sales of four consumer durable goods. Empirical applications show the benefits, as well as the limitations of the proposed model.

• Journal of the Korea Institute of Building Construction
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• v.5 no.1 s.15
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• pp.81-88
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• 2005

As a part of efforts for conformity of demand to high quality of concrete and for solution of economic problem, blast-furnace slag has been utilized by means of cement replacement. With utilization of blast-furnace slag, superior performance can be ensured, environmental pollution can be prevented and economical advantage can be obtained. But blast-furnace slag has a lot of disadvantages like retardation of strength manifestation etc. in field construction, so properties examination of concrete using blast-furnace slag instead of cement is necessary. For upper necessity, it is planed that basic data for utilization and performance management of blast-furnace slag by means of cement replacement is presented with experimental comparison and investigation of engineering properties of concrete according to the replacement ratio and fineness of blast-furnace slag.

• Korean System Dynamics Review
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• v.3 no.1
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• pp.79-104
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• 2002

A system dynamics project is going on for forecasting automobile market in Korea. The project is made up of three stages, and the first stage has been wrapped up. As the first attempt, most efforts have been focused on the sound foundation rather than the exact forecast. The model consists of three sectors; the supply sector, the demand sector, and the population sector. The supply sector is a simple stock and flow diagrams representing the supply capacities of all automobile types. The major effort is made on the demand sector and the population sector. The demands are divided into three categories; replacement demands, new demands, and additional demands. The model applies “one car per person" concept, and assumes there will be no additional demands for a while. The replacement demands are calculated based on a simple stock and flow diagram. The new demands are calculated via Bass models; each bass model represents a diffusion for each age group. The population is divided into 101 age groups (age 0 to age 100). The model has been calibrated with past 10 year data (1990 - 1999), and tested for the next two years (2000-2001). The results ware acceptable, although a fine tuning is required. Now the second stage is going on, and most of efforts are made how to incorporate the economic and cultural factors.

• Korean journal of food and cookery science
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• v.32 no.4
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• pp.492-502
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• 2016

Purpose: The purposes of this study were to identify the segments of the Home Meal Replacement (HMR) market according to food-related lifestyle of Japanese consumers, and to investigate its demographic characteristics, the HMR purchase status and needs of new HMR product development. Methods: A total of 2,720 domestic consumers living in Japan were surveyed using a self-administered questionnaire and 488 responses were returned. Excluding responses with significant missing data, 467 responses were used for data analysis. Results: As a result of cluster analysis, three consumer segments were identified. The diet-highly concerned segment had the highest food-related lifestyle score, followed by the diet-moderately concerned segment, and the diet-unconcerned segment (p<0.001). A significant difference in demographic characteristics among the three segments was found with respect to the type of residence (p<0.05). There were significant differences in the main place (p<0.01) and average expense (p<0.001) for HMR purchases by food-related lifestyle segments. In the case of new HMR products that need further development, 'low-sodium products' had the highest demand scores in all three segments. In the diet-highly concerned segment, the mean scores of demand for new products were significantly higher than those in the other segments (p<0.001). Conclusion: The findings of this study can be used to develop new products for the Japanese' HMR market. The segments identified in this study should be updated and revised regularly to reflect changes in the characteristics of each food-related lifestyle segment.

• Journal of the Korean Society of Systems Engineering
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• v.18 no.1
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• pp.1-13
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• 2022

The Yongin Light Rail train was manufactured by Bombardier Transportation in Canada in 2008 and is a privately invested railway line that has been operating in Yongin-si, Gyeonggi-do, since 2013. When the frequency of train failure increases due to aging, and there is a delay in the delivery period of imported parts used in the Bombardier manufactured trains, timely vehicle maintenance may not be performed due to lack of parts. To solve this problem, it is necessary to build a 'vehicle parts maintenance demand forecasting system' that analyzes the accurate and actual maintenance demand annual based on the condition of vehicle parts. The full scope of analysis in this paper analyzes failure data from various angles after opening of Yongin light rail vehicle to analyze failure patterns for each part and identify replacement cycles according to possible failures and consumption of parts. Based on this study, it is expected that Yongin Light Rail's maintenance system will change from the existing time-based replacement (TBM) concept to the condition-based maintenance (CBM) concept. It is expected that this study will improve the efficiency of the Yongin Light Rail maintenance system and increase vehicle availability. This paper is a fundamental for establishing of a system for predicting the replacement timing of vehicle parts for Yongin Light Rail. It reports the results of data analysis on some vehicle parts.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.101-103
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• 1998

뉴스기사를 구성하는 NOD데이터는 VOD(Video on Demand) 데이터와는 달리 미디어의 종류 및 크기, 시간적인 접근 지역성, 사용자와 상호 작용성 등의 차이점을 가질 뿐만 아니라 새로운 뉴스기사가 수시로 생성되고 사용자가 인기도가 높은 기사와 최신의 뉴스기사에 더 많이 접근하는 특성을 가진다. 본 논문에서는 현재 서비스중인 전자신문의 로그파일을 분석하여 NOD 뉴스기사의 인기도가 Zipf분포와 다름을 보이고, 뉴스기사의 생명주기Lifr Cycle)에 따른 접근 확률분포 제시한다. NOD 데이터의 접근 편기성으로 인하여 데이터 캐싱을 통한 NOD 서버의 성능 향상을 기대할 수 있으나 뉴스기사의 생명주기가 짧고 접근시간대별로 사용자 접근형태가 변하는 등의 이유로 단순히 인기도만 고려한 캐싱은 빈번한 데이터 재배치 문제로 인해 높은 캐시 관리비용을 야기한다. 따라서 본 논문에서는 뉴스 기사의 접근 편기성에 나타나는 인기도(popularity)와 생명주기를 조합한 척도를 제안하고 이를 이용한 재배치를 제안한다.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1511-1518
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• 2017

Renewable energy hybrid systems look into the process of choosing the finest arrangement of components and their sizing with suitable operation approach to deliver effective, consistent and cost effective energy source. This paper presents hybrid renewable energy system (HRES) solar photovoltaic, downdraft biomass gasifier, and fuel cell based generation system. HRES electrical power to supply the electrical load demand of academic research building sited in $23^{\circ}12^{\prime}N$ latitude and $77^{\circ}24^{\prime}E$ longitude, India. Fuzzy logic programming discover the most effective capital and replacement value on components of HRES. The cause regarding fuzzy logic rule usage on HOMER pro (Hybrid optimization model for multiple energy resources) software program finds the optimum performance of HRES. HRES is designed as well as simulated to average energy demand 56.52 kWh/day with a peak energy demand 4.4 kW. The results shows the fuel cell and battery bank are the most significant modules of the HRES to meet load demand at late night and early morning hours. The total power generation of HRES is 23,794 kWh/year to the supply of the load demand is 20,631 kWh/year with 0% capacity shortage.

• Journal of the Korea Institute of Building Construction
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• v.10 no.2
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• pp.41-50
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• 2010

This study presented a model that can enable a reliability analysis for the repair and replacement cycle of a building by using background repair and replacement data and expert opinion as foundation data and applying Monte Carlo Simulation. The presented model offers the time of the repair and replacement of building elements for the period of a year, and supports the prediction of repair and replacement and expenses demand in advance while planning the maintenance of a building. In addition, the model will significantly reduce the risks to the building owner with regard to maintenance decisions. In addition, when a person in charge of the maintenance of large-scale building assets is having difficulties making decisions regarding the repair and replacement of existing building elements due to a lack of background data to support a long-term policy on the repair and replacement requirements, an engineering solution that can ensure the adequacy of this is provided. In summary, it can be largely divided into three study results. First, a method of estimating the repair and replacement cycle that can deal with the development of a construction system was developed. Second, a probabilistic methodology that can quantify the risk of the repair and replacement cycle was proposed. Third, the proposed model can be used as a means of supporting designer and constructor in making decisions for the life cycle plan of a building during a construction project.

• Journal of Biomedical Engineering Research
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• v.41 no.6
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• pp.256-263
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• 2020

The importance of quality control has been emphasized to maintain safety of patients and satisfaction of medical service with medical devices used in clinic. Accordingly, objective evaluation method and standards consistently has been brought up for demand to replace outdated medical devices in appropriate time and to maintain the quality of medical service. Though many studies made suggestions methods to determine what medical devices to be replaced first, these methods were difficult in practice for its complex evaluation criteria and long time to evaluate. Therefore, in this study, a simple evaluation method is developed to identify and prioritize medical devices that are ought to be replaced. For the development of this simple evaluation method, four major characteristics of technology, safety, finance, and user satisfaction, which are considered in clinics to evaluate medical device replacement, and 14 minor attributes are distinctively selected. Each characteristic is assessed in binary form of "YES" or "NO" to minimize its subjective nature. Using this method to evaluate sampled medical devices belonging to four different characteristics, devices are suggested to be replaced in the current financial year or in the following financial year, or re-evaluated by the end of this financial year. Such results of evaluation can amend the subjective nature of existing evaluation method and give objective standards more promptly.

• Journal of Korea Planning Association
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• v.54 no.4
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• pp.71-78
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• 2019

Due to the rapid pace of low fertility and aging of Korea, population decline is rapidly progressing in the outskirts of the province and county. Demand for public transport is decreasing due to suburban population declines, while local government funding for maintenance of the bus system is expected to increase gradually. The government and municipalities are promoting the introduction of Demand Responsive Transport (DRT) in order to reduce the burden of financial support for buses while enhancing mobility of the residents in vulnerable areas. However, most DRTs in Korea have been operated mainly in the areas that are not provided with public transportation services. Although DRT is able to reduce the financial burden of local governments, it is not easy to be introduced because of the objection of the existing bus users. In this study, 11 out of 61 towns with poor public transportation services in Gyeongsangnam-Do were selected for the introduction of DRT to replace bus services by using village characteristics. The results of this study are expected to be used as a basis for decision making to use DRT instead of bus service for the burden of bus financing for local governments.