• Industrial Engineering and Management Systems
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• 제13권3호
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• pp.304-318
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• 2014

It is necessary for a retailer to improve responsiveness to uncertain customer demand in product sales. In order to solve this problem, this paper discusses an optimal operation for a 2-stage-ordering-production system consisting of a retailer and a manufacturer. First, based on the demand information estimated at first order time $t_1$, the retailer determines the optimal initial order quantity $Q^*_1$, the optimal advertising cost $a^*_1$ and the optimal retail price $p^*_1$ of a single product at $t_1$, and then the manufacturer produces $Q^*_1$. Next, the retailer updates the demand information at second order time $t_2$. If the retailer finds that $Q^*_1$ dissatisfies the demand indicated by the demand information updated at $t_2$, the retailer determines the optimal second order quantity $Q^*_2$ under $Q^*_1$ and adjusts optimally the advertising cost and the retail price to $a^*_2$ and $p^*_2$ at $t_2$. Here, decision-making approaches for two situations are made-a decentralized supply chain (DSC) whose objective is to maximize the retailer's profit and an integrated supply chain (ISC) whose objective is to maximize the whole system's profit. In the numerical analysis, the results of the optimal decisions under DSC are compared with those under ISC. In addition, supply chain coordination is discussed to adjust the unit wholesale price at each order time as Nash Bargaining solutions.

• 보건행정학회지
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• 제21권1호
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• pp.115-131
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• 2011

Several common issues are encountered by countries - Germany, Japan, and the United States - that adopted long-term care (LTC) system. First, the demand for LTC and its associated costs have steeply risen following the implementation of the LTC policy. Second, ensuring the quality of services have been difficult. Third, the coordination of services among providers and between LTC and medical care has been inadequate. Learning from their experience, we suggest ways to improve the LTC system in Korea. The basic approach aims for efficiency over equity in the system. This would require promoting provider competition and consumer choice. We propose several policy options according to the major stakeholders. For consumers, cash benefits at fixed rates and personal savings accounts are feasible options to self-contain the demand and cost of services. On the insurer's side, creating an environment of multiple insurers will engender competition, leading to cost savings and quality care. For providers, delivery of quality services through competition, cost-containment through capitated reimbursements, and coordination of services through integrated delivery system can be achieved. From the assessors' perspective, establishing an information system to monitor the activities of insurers and providers would be important, empowering consumers with information to choose cost-effective service providers. In summary, the suggested approach would provide cost-effective LTC services by guaranteeing consumer choice and promoting major stakeholder accountability. Further studies are needed to test the feasibility of this model in ensuring quality LTC in Korea.

• 한국농공학회논문집
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• 제63권6호
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• pp.1-16
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• 2021

Global warming due to climate change is expected to significantly affect the hydrological cycle of agriculture. Therefore, in order to predict the magnitude of climate impact on agricultural water resources in the future, it is necessary to estimate the water demand for irrigation as the climate change. This study aimed at evaluating the future changes in water demand for irrigation under two Shared Socioeconomic Pathways (SSPs) (SSP2-4.5 and SSP5-8.5) scenarios for paddy rice in Gimje, South Korea. The APEX-Paddy model developed for the simulation of paddy environment was used. The model was calibrated and validated using the H₂O flux observation data by the eddy covariance system installed at the field. Sixteen General Circulation Models (GCMs) collected from the Climate Model Intercomparison Project phase 6 (CMIP6) and downscaled using Simple Quantile Mapping (SQM) were used. The future climate data obtained were subjected to APEX-Paddy model simulation to evaluate the future water demand for irrigation at the paddy field. Changes in water demand for irrigation were evaluated for Near-future-NF (2011-2040), Mid-future-MF (2041-2070), and Far-future-FF (2071-2100) by comparing with historical data (1981-2010). The result revealed that, water demand for irrigation would increase by 2.3%, 4.8%, and 7.5% for NF, MF and FF respectively under SSP2-4.5 as compared to the historical demand. Under SSP5-8.5, the water demand for irrigation will worsen by 1.6%, 5.7%, 9.7%, for NF, MF and FF respectively. The increasing water demand for irrigating paddy field into the future is due to increasing evapotranspiration resulting from rising daily mean temperatures and solar radiation under the changing climate.

• 한국수자원학회논문집
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• 제30권1호
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• pp.45-54
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• 1997

수돗물, 송배수펌프의 운전 등 상수도시설을 합리적인 운용을 위해서는 일, 또는 시간 단위의 급수량 사용량의 추정이 필수적이다고 할 수 있다. 급수량의 추정방식은 회귀모형식 및 시계열 분석방법이 있는데, 본 연구에서는 시계열 분석방법인 ARIMA모형을 이용하여 일일 급수량을 추정하였으며 연구대상 지역으로는 광주광역시를 선정하였다. 일일 급수량을 추정하는데 있어서 시계열장을 15, 30. 60, 90일로 나누어 각각의 시계열장에 대해 시행착오법으로 각 모형에 적용하여 최적의 시계열장을 결정하여, 상수도 일일 급수량을 추정할 수 있는 모형을 제안하고 그 유효성을 잔차분석을 통해 검증하였다. 제안된 모형식은 사고 등의 인위적인 조작(단수 등)이 가해지는 시기를 제외하고는 실측치와 모형의 추정치와의 오차율이 최대 약 12%, 평균 3% 이내로 나타나, 모형의 결과는 상수도 일일 급수량의 추정에 필요한 시설에 적용 가능하다고 판단된다.

• 국제학술발표논문집
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• The 7th International Conference on Construction Engineering and Project Management Summit Forum on Sustainable Construction and Management
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• pp.176-182
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• 2017

The housing market is divided into several sub-markets that operate independently. One of them is the distinction between rental and sales markets. Simultaneously, since the housing is a commodity as well as an asset, it has a close relationship between the rental market and the sales market. Due to the unique structure of Korea, it is difficult to apply the general method to analyze the housing market. This means there is a great deal of concern about side effects from the policy. Actually, the government's subsequent regulation of speculative demand in the future may be necessary to prevent market overheating, but at the same time, there is a fear that the rent will rise. Although changes in policy direction may be inevitable due to changes in market conditions, frequent and sudden changes in policy cause confusion in market participants, causing unrest in the housing market. This study aims to derive main factors and correlation with other housing market factor. These factors will be a base of qualitative housing market model to analyze the market effect of the demand-supply shift. Modeling is based on the system dynamics methodology, which is useful for identifying interactions between variables reflecting various variables in the housing market. The model discussed in this study is expected to provide integrated insight into the key variables of the housing market, away from the monopolistic thinking. It can also be useful as a means of assessing the effectiveness of policies.

• 한국방재안전학회논문집
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• 제6권3호
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• pp.19-27
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• 2013

21세기 녹색성장 시대의 도래와 함께 경제 사회 문화적으로 점차 안정화되면서 사람들은 홍수와 가뭄으로부터 완전한 해방을 기대함과 동시에 생활 터전의 일부로써 친수공간에서 생태적 교류를 갈망하고 있다. 이러한 시대적 요구의 변화에 적응하기 위해서는 하천관리 정책의 포커스도 기존의 단순한 수해방지를 탈피한 재해예방과 함께 자연의 환경적 생태적 관점을 고려한 종합적인 하천관리가 절실히 요구되고 있다. 따라서 본 연구에서는 이러한 측면을 반영하여 하천이 재해예방과 함께 자연환경과 조화를 이룰 수 있게 정비 관리될 수 있는 해법을 제안하였다. 이를 위해 필요한 것은 유역종합치수계획에 의한 치수정책, 국가주도의 하천관리, 돌발홍수 대처능력 강화, 그리고 자연형 하천정비의 확대 등의 추진이 환경적으로 건전하고 지속가능한 개발에 접근하는 것이라고 본다.

• 산업공학
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• 제25권3호
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• pp.338-346
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• 2012

Regarding the green environment, it is important to boost the spread of environmentally friendly vending machines and to operate the vehicles for their inventory replenishments while minimizing emissions of greenhouse gases. In general, the vending machine management company lacks capability to operate the supply chain effectively in an integrated way under the dynamic, complex, and stochastic environment. This paper presents a decision support system, termed DSSVM, for the operations of the general and smart vending machine supply chains with stock-out-based, one stage item substitution in a green logistics environment. The DSSVM supports the estimation of item demand and substitution probabilities, determination of operation parameters, supply chain analysis, what-if analysis, and $CO_2$ analysis for which various analytical models are employed.

• 한국병원경영학회지
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• 제25권2호
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• pp.69-75
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• 2020

Purposes: This study aims to investigate the number of cataract surgeries and predict future trends using 13-year data. Methodology: Trends investigation and comparison of prediction methods was conducted to determine better prediction model using Major Surgery Statistics from Korean Statistical Information Service in 2006-2018. ARIMA(Auto Regressive Integrated Moving Average) was selected and prediction was conducted using R program. Findings: As a results, the number of surgeries will continue to increase. The trends was predicted to increase during January-April, and it declined over time and was the lowest in August. Pratical Implications: Therefore, it is necessary that management will be needed by continuously investigating and predicting the demand and trend for surgery to prepare an alternative to the increase.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.43-44
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• 2022

Recently, there is a demand for a fast and efficient method for measuring displacement during construction or maintenance of new buildings. As the number of safety accidents caused by structural collapse increases, the integrated management plan of the measurement and management system has become a platform and data is shared with stakeholders, so that it is possible to establish safety management in advance according to the displacement of the structure.

• 한국경영과학회지
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• 제32권1호
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• pp.93-104
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• 2007

We consider a supply chain where products are shipped to warehouse from manufacturing system to customers. Products are supplied from either in-house regular manufacturing or the secondary source such as subcontractor. The inventory in warehouse is controlled by base-stock policy, that is, whenever a demand arrives from customer, an order is released to the manufacturing system. Unsatisfied demand is backlogged. The manufacturing system is modeled as M/M/s+1/c queueing system, and the orders exceeding the given limit care blocked and lost. The steady state distribution of the outstanding orders and the throughput of the manufacturing system are functions of the level of engagement In the secondary source. There is a profit obtained from throughput and cost not only due to the engagement of the secondary source in the manufacturing system but also inventory positions. We want to maximize the total production profit minus the total cost of the production system by simultaneously determining the optimal level of engagement of the secondary source and the optimal base-stock level of the inventory. We develop two algorithms : one without guarantee of the optimal solution but with the small number of computations, the other optimal but with more computations.