• 산업경영시스템학회지
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• 제39권4호
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• pp.137-146
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• 2016

In recent years, business environment is faced with multi uncertainty that have not been suffered in the past. As supply chain is getting expanded and longer, the flow of information, material and production is also being complicated. It is well known that development service industry using application software has various uncertainty in random events such as supply and demand fluctuation of developer's capcity, project effective date after winning a contract, manpower cost (or revenue), subcontract cost (or purchase), and overrun due to developer's skill-level. This study intends to social contribution through attempts to optimize enterprise's goal by supply chain management platform to balance demand and supply and stochastic programming which is basically applied in order to solve uncertainty considering economical and operational risk at solution supplier. In Particular, this study emphasizes to determine allocation of internal and external manpower of developers using S&OP (Sales & Operations Planning) as monthly resource input has constraint on resource's capability that shared in industry or task. This study is to verify how Stochastic Programming such as Markowitz's MV (Mean Variance) model or 2-Stage Recourse Model is flexible and efficient than Deterministic Programming in software enterprise field by experiment with process and data from service industry which is manufacturing software and performing projects. In addition, this study is also to analysis how profit and labor input plan according to scope of uncertainty is changed based on Pareto Optimal, then lastly it is to enumerate limitation of the study extracted drawback which can be happened in real business environment and to contribute direction in future research considering another applicable methodology.

• 한국화재소방학회논문지
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• 제27권1호
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• pp.20-25
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• 2013

본 연구에서 부속실 단독 가압 구조인 급기가압 제연설비의 성능 확보에 영향을 주는 주요 매개 변수를 분석하고 공급유량과 누설면적 변화에 따라서 풍도와 부속실 차압 형성 관계를 실험적으로 분석하였다. 이를 위해서 3층 규모의 총 10개의 구획공간으로 구성된 모형 구조물과 방화문의 개폐력 측정장치를 제작하였으며, 각 구획공간과 외기의 차압, 방연풍속을 측정하기 위한 제어 계측 장비를 구성하였다. 그 결과 댐퍼의 차압조절 범위가 45 Pa~55 Pa인 경우 공급유량과 부속실 차압 크기에 따라서 45 Pa 이하인 저압 영역, 45 Pa~55 Pa 구간인 차압조절 영역 그리고 55 Pa 이상인 과압 영역을 구분하였으며, 저압 영역에서는 부속실, 차압조절 영역에서는 부속실과 댐퍼 그리고 과압 영역 에서는 댐퍼의 누설면적이 차압 형성에 중요한 관계를 갖고 있는 것을 확인하였다.

• 한국농공학회논문집
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• 제60권2호
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• pp.121-132
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• 2018

Along with climate change, it is reported that the extreme climate events such as severe drought could cause difficulties of agricultural water supply. To minimize such damages, it is necessary to secure the agricultural water resources by using or saving the amount of irrigation water efficiently. The objectives of this study were to develop paddy water management scenarios and to evaluate their effectiveness on water saving. Three water management scenarios (a) deep irrigation with ponding depth of 20~80 mm (control, CT), (b) no/intermittent irrigation until paddy cracks (water management A, WM-A), and (c) intermittent irrigation with ponding depth under 20 mm (water management B, WM-B) were developed. Water saving effects were analyzed using monitored data from experimental paddy fields, and agricultural water supply was analyzed on a reservoir-scale using MASA model. The observed irrigation amounts were reduced by 21 % and 17 % for WM-A and WM-B compared to CT, respectively, and mainly occurred by the increase of effective rainfall. The simulation results showed that water management scenarios could reduce irrigation by 21~51 % and total inflow by 10~24 % compared to CT. The long-term simulated water level change of agricultural reservoir resulted in the decrease of dead level occurrence for WM-A and WM-B. The study results showed that WT-A and WT-B have more benefit than CT in the aspect of agricultural reservoir water supply.

• Journal of Information Technology Applications and Management
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• 제15권3호
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• pp.79-90
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• 2008

With the corporate environment nowadays being surrounded by plenty of information, the sharing of information among businesses through mutual cooperation tops the list of hot issues. Predictions of demands from the customer, business, or consumer by sharing information can affect the inventory and order production system. However, notwithstanding the importance of sharing information, empirical studies on quantitative use of information still remain insufficient in spite of many a discussion now being made on the sharing of information. This paper proposes to examine the ways meteorological information may affect the rises in the achievements of supply chains in distributive businesses, the kind of information that noticeably affects the consumer behavioral patterns in the distributive businesses but rarely perceived as a form of information shared by businesses. This study is based on a model in which meteorological information has been added as the one used to predict demands, after the beer distribution game has been modified to fit the current status, and simulations under an assumptive situation, where decisions are made on a daily basis, were conducted 50 times for a period of 1000 days for the generalization of the results, while at the same time a Duncan Test was conducted to determine the threshold to use the meteorological information that will be most profitable to the retailer, wholesaler, supplier and the supply chain as a whole. Our findings indicate that corporations have thresholds that vary from business to business depending upon the ratio of backlog costs to inventory costs. At the same time, our findings also show that there existed effective thresholds depending upon the ratio of backlog costs to inventory costs for the performance of the overall supply chain.

• 디지털융복합연구
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• 제11권9호
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• pp.103-111
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• 2013

SCM의 관리 포인트가 공급중심에서 수요관리 중심으로 옮겨짐에 따라, 정확한 수요 예측을 위한 많은 기법들이 제시되어 왔다. 이 중 변수간의 인과관계 분석을 통한 수요예측이 많이 이루어지고 있음에도 불구하고, 연관된 변수들 간의 상관구조는 상관계수에 의존하였고, 이는 예측의 정확성을 저하시키는 요인으로 작용하였다. 본 논문에서는 기존 방법의 문제점들을 보완하며, SCM에서 발생하는 Heavy Tail형 데이터의 상관구조를 정밀하게 모델링할 수 있는 방법을 제시한다. 상관구조를 파악할 수 있는 프레임웍인 코플라 함수 중에서 Student's t-코플라 함수를 통하여 수요 예측모형을 수립하고, 관련 파라미터를 추정하는 기법을 실험과 함께 제시하였다. 이를 통해, 수요예측에 필요한 변수들 간의 상관구조 파악이 보다 명확해지며, 이는 SCM상의 채찍효과의 완화로 이어져, 안정된 공급 사슬 네트웍의 관리에 기여할 것으로 기대된다.

• 한국농공학회논문집
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• 제63권5호
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• pp.95-105
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• 2021

Drought is a disaster that causes prolonged and wide scale damage. Recently, the severity and frequency of drought occurrences, and drought damage have been increased significantly due to climate change. As a result, a quantitative study of drought factors is needed to better understand and prevent future droughts. In the case of agricultural drought, several existing studies examine the economic damage caused by droughts and their causes, but these studies are not well suited to estimating crop-oriented agricultural drought damage and the factors that absolutely affect agricultural drought. This study determines which factors most affect agricultural drought. It examines meteorological factors and those related to agricultural water supplied by irrigation facilities. Rice paddy production per unit area is lower than the average from the last two years where agricultural drought occurred. We compare the relative frequency of agricultural drought impacts with irrigation facilities, effective reservoir storage, the number of water supply facilities, and the meteorological drought index such as Standardized Precipitation Index (SPI). To identify factors that affect agricultural drought, we correlate rice paddy production anomalies with irrigation water supply for the past two years. There was a high positive correlation between rice paddy production and irrigation water usage, and there was a low or moderate negative correlation between rice paddy production anomalies compared to the average of the past two years and SPI. As a result, agricultural water supply by irrigation facilities was judged to be more influential than meteorological factors in rice paddy production. This study is expected to help local governments establish policies related to agricultural drought response.

• 한국화재소방학회논문지
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• 제32권6호
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• pp.15-21
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• 2018

본 연구에서는 급기가압 조건에서 거실, 부속실 및 계단실로 구성된 복합 구획 공간에 대해 화재해석을 수행하고 가압 및 환기 조건에 따른 화재 연기의 유동 특성을 분석하였다. 화재 해석은 유효누설면적을 측정하기 위해 제작된 누기율 시험설비에 대하여 수행하였으며, 화재의 거시적 특성과 각 구획에 대한 유동 및 압력 특성의 분석을 통해 급기가압 조건에서의 화염 및 연기 거동에 대한 이해를 증진시키고자 하였다. 화재 해석 결과는 화재 발열량의 크기가 환기 시스템에 의해 공급되는 공기량에 의해서 민감하게 영향을 받게 됨을 보여주었다. 거실과 부속실에서의 속도분포 분석 결과를 통해 급기가압의 조건에서도 화재 연기가 문의 상층부를 통해 부속실로 유출될 수 있음을 확인하였다. 이를 통하여 급기가압 제연시스템의 설계와 적용에 있어서 화재 크기와 공간적 특성과 같은 요인을 고려하는 것이 매우 중요하다는 것을 확인할 수 있었다.

• Membrane and Water Treatment
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• 제15권2호
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• pp.59-66
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• 2024

This study evaluated the performance of a membrane aerated biofilm reactor (MABR) for nitrogen removal from a high-strength ammonia nitrogen-containing wastewater. The experimental setup consisted of four compartments that are sequentially anaerobic and aerobic to achieve complete nitrogen removal. The last compartment of the reactor setup contained a membrane bioreactor (MBR) to reduce sludge production in the system and to obtain a better-quality effluent. Continuous experiment over a period of 47 days showed that MABR exhibited excellent NH₄⁺-N removal efficiency (99.5%) compared to the control setup without MABR (56.5%). The final effluent NH₄⁺-N concentration obtained in the MABR was 2.99±1.56 mg/L. In contrast to NH₄⁺-N removal, comparable TOC removal values in the MABR and the control reactor (99.2% and 99.3%, respectively) showed that air supply through MABR is much more critical for denitrification than for organic removal. Further study to understand the effect of air supply rate and holding pressure on NH₄⁺-N removal in MABR revealed that an increase in both these parameters positively impacted reactor performance. These parameters are related to oxygen supply to the biofilm formed over the membrane surface, which in turn influenced NH₄⁺-N removal in MABR. Among the two different strategies to control biofilm over the membrane surface, results showed that scouring for a duration of 10 min on a weekly basis, along with mixing air supply, could be an effective method.

• 농촌의학ㆍ지역보건
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• 제49권3호
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• pp.235-256
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• 2024

Background: The adequate provision of medical care relies on the availability of a suitable number of healthcare professionals. To ensure stability in healthcare delivery, it is crucial for a country to accurately estimate and address the supply of doctors. This study aims to contribute to the formulation of effective policies for securing and distributing doctor manpower, with a focus on medically underserved areas at both the national and local government levels. Methods: Employing the system dynamics methodology, this research utilizes stock and flow diagrams, including level and rate diagrams, to quantitatively analyze the cumulative structure of the doctor supply and demand system. Results: The analysis reveals a substantial shortage of clinical doctors in Gyeongsangnam-do, amounting to 15,477 as of 2021. Projections indicate a need for an additional 7,570 doctors by the year 2050 to maintain the current healthcare service level. Examination of medical treatment rights and distribution across cities and counties indicates an insufficiency in doctor supply relative to demand in the majority of regions. Alternative scenarios, such as increasing medical school enrollments and adjusting retirement ages, were explored, yet none provided a sufficient resolution to the shortage. Conclusion: The findings underscore an impending exacerbation of the doctor shortage in Gyeongsangnam-do if the existing system is perpetuated. Addressing this issue necessitates not only augmenting the number of medical school students and adapting retirement age policies but also implementing diverse strategies employed successfully in other countries. This study serves as a foundational step in informing evidence-based policies aimed at securing an ample and appropriately distributed doctor workforce for sustainable healthcare delivery.

• 한국조경학회지
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• 제49권2호
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• pp.113-127
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• 2021

공원녹지와 물길을 연결하는 조경계획기법이 보편화되었지만, 대규모 계류형 수경시설의 운영과 관리상의 문제가 빈번하게 발생하고 있다. 이에 본 연구는 전주·완주 혁신도시를 대상으로 빗물을 이용한 계류형 수경시설의 지속가능한 관리와 운영을 모색할 수 있는 설치방안을 검토하였다. 이 연구의 목적을 수행하기 위해 수원지와 수로 부분으로 나누어 각각의 시나리오를 설정하였다. 첫째, 수원지에 관한 시나리오는 수로와 수원지에 필요한 유지용수량과 저장공간을 산정하기 위해 물수지를 분석하였다. 분석 결과, 수로 부분 자체는 676.8톤/월의 급수가 필요하지만, 수원지의 생태적 또는 경관적 측면을 고려하여 3,018톤~5,512톤의 저장 공간과 0.75m~1.37m의 수심 유지가 요구되었다. 둘째, 수로에 관한 시나리오는 계류형 수경시설의 유지관리에 효과적인 설비의 계통을 선정하는 것이다. 이를 위해 용수를 고지대로 압송하여 흘려보내는 단일순환계통과 각각의 수공간에 별도 공급하여 독립 운전하는 다중순환계통을 비교 분석하였다. 그 결과, 소규모 동력장치에 의해 독자적으로 운전하는 다중순환계통이 용수공급에 필요한 운전시간을 최소화 할 수 있어 더 효과적인 것으로 나타났다.