• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.1
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• pp.141-150
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• 2014

Due to their accessibility and 24-hr availability, convenience stores are an integral part of daily lives. Because they sell a limited number of products and have small shelf space, shelf space allocation and inventory replenishment are important considerations for inventory management that critically affect profit. In this paper, we propose five solutions for the vendor-managed inventory problem of convenience stores that maximize profit while considering stock-out-based product substitutions. The performance of the proposed solutions is evaluated via simulation to reflect the demand uncertainty and marketing activity.

• KDI Journal of Economic Policy
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• v.24 no.1
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• pp.45-112
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• 2002

Enhancing labor market flexibility is currently posted as one of the major economic policy objectives in Korea. However, the labor market effects of specific policies to achieve it have not been sufficiently investigated. This paper takes up the issue of employment protection deregulation and surveys and empirically analyzes its policy effects. Academic researches generally confirm that deregulation tends to promote labor turnover and employment of the disadvantaged groups such as the youth and female by raising the overall efficiency of the economy, but its effects on unemployment is not clear. In the Korean labor market, both job creation and destruction, and labor mobility have increased after the economic crisis of 1998, but they can not be seen as deregulation effects as the changes are confined to the temporary and daily employment whose labor markets are least regulated whereas the regular employment market remains virtally unchanged. Such results suggest that labor market deregulation need to be pursued consistently as a policy goal since the labor demand condition shift and the need for expanding regular employment necessitates it, for which detailed policy agenda for removing market inefficiencies should be carefully arranged.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.3
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• pp.315-319
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• 2020

The modern transportation and mobility sector is expected to encounter high penetration of Electric Vehicles (EVs) because EVs contribute to reducing the harmful emissions from fossil fuel-powered vehicles. With the prospective growth of EVs, sufficient and convenient facilities for fast charging are crucial toward satisfying the EVs' quick charging demand during their trip. Therefore, the Fast Electric Vehicle Charging Stations (FECS) will be a similar role to gas stations. In this paper, we study a charging scheduling problem for the FECS with solar photovoltaic (PV) and an Energy Storage System (ESS). We formulate an optimization problem that minimizes the operational costs of FECS. There are two cost and one revenue terms that are buying cost from main grid power, ESS degradation cost, and revenue from the charging fee of the EVs. Simulation results show that the proposed scheduling algorithm reduces the daily operational cost by effectively using solar PV and ESS.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.64-66
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• 2007

Photovoltaic power systems convert sunlight directly into electricity. A residential PV power system enables a homeowner to generate some or all of their daily electrical energy demand on their own roof, exchanging daytime excess power for future energy needs In this paper, It was suggested that new design method for PV system installation for the purpose of system efficiency improvement. and according to loss parameter compensation method, designed for the PV system and investigated through the simulation practically.

• Industrial Engineering and Management Systems
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• v.12 no.2
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• pp.95-102
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• 2013

It is difficult to determine an appropriate discount price for daily perishable products to increase profit from a long-term standpoint. Even if the discount pricing is efficient to increase profit of the day, consumers memorize the sales price and they might hesitate to purchase the product at a regular price the following day. The authors discussed the inventory clearance pricing for a single period in our previous study by constructing a mathematical model to derive an optimal sales price to maximize the expected profit by considering the reference price effect of demand. This paper extends the discussion to handle the discount pricing for multiple periods. A mathematical analysis is first conducted to reveal the properties on an objective function, which is the present value of total expected profits for multiple periods. An algorithm is then proposed to derive an optimal price for asymmetric consumers. Numerical experiments investigate the characteristics of the objective function and optimal pricings.

• International Journal of High-Rise Buildings
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• v.12 no.1
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• pp.11-18
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• 2023

The urbanity of high-rise buildings does not simply reference their physical characteristics but also encompasses their impact on the overall urban environment and the daily lives of citizens. This involves the economic benefits, social development, urban culture and public activities that high-rise buildings bring to a city. High-rise buildings are an important aspect of urban development and play a crucial role in providing public services in high-density urban habitats. However, to ensure that their contribution to the city is positive, it is essential to take into account their impact on surrounding buildings and the built environment. This paper analyzes their urban attributes and value system and summarizes their current development status. In short, as the demand for public services continues to evolve, it is necessary for high-rise buildings to keep up with these changes by continuously enhancing their urbanity.

• The Korean journal of internal medicine
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• v.39 no.4
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• pp.547-554
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• 2024

The incidence and mortality of colorectal cancer (CRC) have decreased through regular screening colonoscopy, surveillance, and endoscopic treatment. However, CRC can still be diagnosed after negative colonoscopy. Such CRC is called interval CRC and accounts for 1.8-9.0% of all CRC cases. Most cases of interval CRC originate from missed lesions and incompletely resected lesions. Interval CRC can be minimized by improving the quality of colonoscopy. This has led to a growing interest in and demand for high-quality colonoscopy. It is important to reduce the risk of CRC and its associated mortality by improving the quality of colonoscopy. In this review article, we provide an overview of colonoscopy quality indicators, including bowel preparation adequacy, the cecal intubation rate, the adenoma detection rate, the colonoscopy withdrawal time, appropriate polypectomy, and complication of the procedure. Because colonoscopy is a highly endoscopist-dependent procedure, colonoscopists should be well-acquainted with quality indicators and strive to apply them in daily clinical practice for the prevention of CRC.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.327-334
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• 2006

In tomato perlite bag culture, the available water content was analyzed for several sorts of perlite so that the irrigation safety was investigated and thus the irrigation strategy controlled by time clock was established. The reduction trends of water content in perlite bags were monitored for tomatoes, of which fruits were harvested until the fifth cluster. The amount of daily reduction of water in the bag was on the decrease as the total water in the bag was decreased. In terms of time interval from when the water content based on weight was reduced more than 50g to when it was dropped again, the longest time interval in a day was retarded gradually. It means plant activity was recovered later than the previous day. The available water content in perlite bag of 40 liters was about 30% which was 12 kg in weight, which satisfied daily water demand of 6 tomato plants. The appropriate time irrigated by time clock was recommended for the case that it was irrigated 5 or 10 times a day with the daily integrated solar radiation of 601 or $1,519W/m^2$.

• Research in Community and Public Health Nursing
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• v.14 no.1
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• pp.106-119
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• 2003

This study was executed to develop the model of the format of the day care center which supplies the total service on the health care in the day time and social program related with the work and to evaluate the processing courses which was adjusted for 3 years from March 1999 to December 2001 in order to improve the quality of life of the family who experience dementia, dementia prevention, and the old and the burden of daily activities. The processing courses of this business model were evaluated to the confirmation on the health condition, application of the nursing processes, and the precise medical examination, and 20 sorts of social programs. The methods used in this model were the simplified MMSE-K, Ability for ,Daily Life(ADL), Instrumental Activities of Daily Living(IADL), and nursing process, and so on. The execution effects of this model are as follows. 1. It can contribute to the delay in the dementia process of the old people who are related with the dementia and maintenance and improvement of the health by confirming the stopping of the process of the dementia as the objective estimation method while the dementia symptom is maintained as the current condition through the medical and social total services. 2. The reduction of the burden for the daily care of the subject people and their families for the old people who are concerned with the dementia helped to improve the quality of life of the subject people and their family by enabling them to have jobs. 3. It enabled them to positively cope with the demand for the health and nursing of the local residents related to the old people. 4. It enabled them to enhance the recognition for the socialization of the local social organization and residents for the old people. 5. It enabled them to reinforce the related system among the local social organizations, and develop and provide the various social programs which are proper for the old people.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1581-1589
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• 2013

The aim of this study is to suggest a methodology for calculating the peak-hour ratio of passengers at urban railway stations by reflecting the characteristics of passenger demand patterns and the land use inventory of stations. To achieve this, urban railway stations in Seoul are divided into three groups by using factor analysis and cluster analysis. For each station group, we calculate five and four variables related to the passenger demand patterns and the land use inventory of stations, respectively, as well as the peak-hour ratios of passengers. Among these nine variables, average daily passengers and the location quotient (LQ) index for business services are selected as the classification criteria for station groups based on statistical tests. Using the two variables, a group allocation process is suggested to estimate the peak-hour ratio of passengers for a newly-constructed station. Evaluation results based on thirteen stations show that the proposed methodology produces lower errors than the currently-used guideline does. The results of this study contribute to establishing efficiently construction and operation plans for newly-constructed stations.