• 한국물환경학회지
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• 제27권2호
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• pp.200-209
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• 2011

The purpose of the study is to optimally manage sewage treatment plant with analysis of phosphorus contribution and improvement of water quality contributing rate in the effect of inflowing point of effluent and Pal-Dang lake after reducing T-P discharge from large scale public sewage treatment plant at upstream of Pal-Dang lake. Also, this study, for enforcement of T-P in effluent, plans optimal management of effluent T-P through examining propriety of environmental, technological, and economical aspect such as water quality standard of domestic and foreign T-P and related policy. In regarding optimal management of T-P discharged from public sewage treatment plant located in upstream of Pal-Dang lake, the study drew following conclusions. With the optimal management of public sewage treatment plant, it showed that a pollution level became higher in the order of Sumgang E in South-Han river, C in Dalcheon, B1 B2, A in North-Han river, and J in Kyungancheon, and it is required reduction of T-P first. The highest value in analysis of benefit-costs from sewage treatment plant in the selected research area was Kyungan B, and the others are with the order of Jojong A, Bokha A, Kyungan A, and Yanghwa A. With result of this study, all 14 areas are required more enforced phosphorus treatment. The study resulted that the most top priority areas were Hangang F, Sumgang B, and Gyungan A, top priority areas were Bokha A, Dalcheon B, and Cheongmi A, priority areas were Hangang E, Heukcheon A, Gyungan B, and Jojong A, and potential areas were Sumgang A, Yanghwa A, Dalcheon A, and Hangang D. It seems to be appropriate to apply 0.2 mg/L of T-P treatment for water supply source reservation, 0.5 mg/L for the other areas by locally, and 0.2~0.5 mg/L for biological nitrogen phosphorus treatment method and 0.5~1 mg/L for Conventional Activated Sludge by technologically. Also, it may be appropriate to apply 0.2 mg/L for the most top priority area(I), 0.3 mg/L for the top priority area(II), 0.4 mg/L for priority area(III), and 0.5 mg/L for potential area(IV) by the separation of priority area.

• 품질경영학회지
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• 제31권3호
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• pp.185-192
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• 2003

In this paper, the properties on the optimal replacement policies for the general failure model are developed. In the general failure model, two types of system failures may occur : one is Type I failure (minor failure) which can be removed by a minimal repair and the other, Type II failure (catastrophic failure) which can be removed only by complete repair. It is assumed that, when the unit fails, Type I failure occurs with probability 1-p and Type II failure occurs with probability p, $0\leqp\leq1$. Under the model, the system is minimally repaired for each Type I failure, and it is repaired completely at the time of the Type II failure or at its age T, whichever occurs first. We further assume that the repair times are non-negligible. It is assumed that the minimal repair times in a renewal cycle consist of a strictly increasing geometric process. Under this model, we study the properties on the optimal replacement policy minimizing the long-run average cost per unit time.

• 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.

• 품질경영학회지
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• 제18권2호
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• pp.1-8
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• 1990

Replacement policies based on both the system age and the random repair cost are studied. The system is replaced when it reaches age T (Policy A), or when it fails for the first time after age T (Policy B). If the system fails before age T, the repair cost is estimated and repair is then undertaken if the estimated cost is less than a predetermined limit L ; otherwise, the system is replaced. After repair, the system is as good as new with probability (1-p) or is as good as old with probability P. The expected cost rate is obtained, its behavior is examined, and way of obtaining optimal T and L is explored.

• 한국농공학회논문집
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• 제48권7호
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• pp.73-86
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• 2006

Concentrated poultry production in the State of Alabama, U.S.A. results in excessive poultry litter. Application of poultry litter to pastures and row crops serves as a cheap alternative to commercial fertilizer. However, over the years, poultry litter application to perennial forage crops in the Appalachian Plateau region of North Alabama has resulted in phosphorus (P) buildup in soils. Phosphorus index (P-index) and comprehensive nutrient management plans (CNMP) are often used as a best management practice (BMP) for proper land application of litter. Because nutrient management planning is often not done for small animal feeding operations (AFOs), and also because, in case of excess litter, litter transportation infrastructure has not been developed, over application of poultry litter to near by area is a common practice. To alleviate this problem, optimal poultry litter management and transportation infrastructure needs to be developed. This paper presents a methodology to optimize poultry litter application and transportation through efficient nutrient management planning and transportation network analysis. The goal was accomplished through implementation of three important modules, a P-Index module, a CNMP module, and a transportation network analysis module within ArcGIS, a Geographic Information System (GIS). The CNMP and P-Index modules assist with land application of poultry litter at a rate that is protective of water quality, while the transportation network analysis module helps transport excess litter to areas requiring litter in the Appalachian Plateau and Black Belt (a nutrient-deficient area) regions. Once fully developed and implemented, such a system will help alleviate water quality problems in the Appalachian Plateau region and poor soil fertility problems in the Black Belt region by optimizing land application and transportation. The utility of the methodology is illustrated through a hypothetical case study.

• 시큐리티연구
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• 제37호
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• pp.137-163
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• 2013

이 연구는 미국 공립학교의 사례를 통해 학교 내 안전을 미치는 요인과 학교 내 안전에 효율적인 경비형태를 분석함으로서 국내 학교 내 안전을 높일 적절한 방안을 제시하는데 그 목적이 있다. 이 연구는 학교 내에서 발생하는 범죄를 종속변수로 하는 중범죄모델과 범죄의 유형에는 포함되지 않더라도 학생들의 안전을 위협할 수 있는 비행행위 및 집단행위로 범위를 한정시켜 종속변수로 하는 학교폭력모델로 나뉜다. 첫 번째, 학교 내 안전에 영향을 미치는 요인의 분석결과, 중범죄안전 모델과 학교폭력 안전 모델의 설명력은 각각 10.3%, 12%이며, 중범죄안전 모델을 살펴보면 학생을 대상으로 한 안전교육(t=2.521, p=0.012), 학교활동 부모참여(t=11.733, p=0.000), CPTED활동(t=3.206, p=0.001), 학교 내 경비활동(t=2.983, p=0.003)이 통계적으로 유의미하게 중범죄로 부터의 안전에 긍정적인 영향을 미치는 요인으로 나타났다. 학교폭력안전 모델에서도 유사하게 학교활동의 부모참여(t=10.399, p=0.000), CPTED활동(t=7.238, p=0.000), 학교내 경비활동(t=4.018, p=0.000)이 통계적으로 유의미하게 학교폭력으로 부터의 안전에 영향을 미치는 요인으로 나타났다. 두 번째, 어떠한 유형의 경비활동이 학교 내 안전을 높이는지 분석한 결과, 중범죄안전 모델과 학교폭력안전 모델, 두가지 모델의 설명력은 각각 4.4%, 3.9%이며, 중범죄 안전 모델에서는 학교에서 실행하는 경비활동 중 지역경찰과의 협조(t=2.112, p=0.035), 교칙관리(t=3.309, p=0.001), 경비순찰활동(t=2.548, p=0.011)이 통계적으로 유의미하게 중범죄로 부터의 안전에 영향을 미치는 요인으로 나타났고, 학교폭력안전 모델에서는 경비활동 중 지역경찰과의 협조(t=2.364, p=0.018), 교칙관리(t=4.142, p=0.000)가 통계적으로 유의미하게 중범죄로 부터의 안전에 영향을 미치는 요인으로 나타났다. 이 연구의 결과에 따라 교사에 대한 교육보다 학생에 대한 교육이 학교 내 안전에 긍정적이고, 학교 운영에 부모참여도 교육과 마찬가지로 지속적이고 계속적인 참여가 학교안전을 위해 필요하다. CPTED활동의 경우, 미국의 사례의 결과를 그대로 받아들여 강화하는 방안을 마련하고, 경비활동에 관하여는 가시성을 높이고 지역경찰과의 협조를 원활히 하는 방안이 학교 내 안전에 긍정적 영향 줄 것이다.

• 한국경영과학회지
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• 제29권1호
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• pp.57-70
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• 2004

Given a tree network on which each node has its own demand and also stands for a candidate location of a potential facility. such as plant or warehouse, the f-median problem on the network (PMPOT) is to select less than or equal to P number of facility locations so that the whole demand on a node is satisfied from only one facility and the total demand occurred on the network can be satisfied from those facilities with the minimum total cost, where the total cost Is the sum of transportation costs and the fixed costs of establishing facilities. Tamir(1996) developed an O(p n$^2$) algorithm for PMPOT which is known to be the best algorithm In terms of the time complexity, where n is the number of nodes in the network, but he didn't make any comments or explanation about implementation details for finding the optimal solution. In contrast to Tamir's work, Kariv and Hakimi(1979) developed O(p$^2$n$^2$) algorithm for PMPOT and presented O(n$^2$) algorithm for finding the optimal solution in detail. In this paper, we not only develop another O(p n$^2$) dynamic programming algorithm for PMPOT that is competitive to Tamir's algorithm in terms of the time complexity, but also present O(n) algorithm that is more efficient than kariv and Hakimi's algorithm in finding the optimal solution. finally, we implement our algorithm on a set of randomly generated problems and report the computational results.

• Nutrition Research and Practice
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• 제14권3호
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• pp.218-229
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• 2020

BACKGROUND/OBJECTIVES: Type 2 Diabetes mellitus (T2DM) is a hereditary disease that is also strongly dependent on environmental factors, lifestyles, and dietary habits. This study explored the relationship between lifestyle habits and glycosylated hemoglobin management in T2DM patients to provide empirical outcomes to improve T2DM management and patient health literacy. SUBJECTS/METHODS: This study enrolled 349 diabetic patients with more than 5 care visits to a Diabetes Mellitus care network under the Health Management Plan led by Taiwan Department of Health (DOH). Based on relevant literature, an Outpatient Record Form of Diabetes Mellitus Care was designed and lipid profile tests were conducted for data collection and analysis. RESULTS: When modeling the data, the results showed that the odds for HbA1c > 7.5% in T2DM patients duration over 10 years was 3.785 (P = 0.002) times that in patients with disease duration of fewer than 3 years. The odds of HbA1c > 7.5% in illiterate patients was 3.128 (P = 0.039) times that in patients with senior high school education or above. The odds of HbA1c > 7.5% in patients with other chronic illness was 2.207 (P = 0.019) times that in participants without chronic illness. Among 5 beneficial lifestyle habits, the odds of HbA1c > 7.5% in patients with 2 or 3 good habits were 3.243 (P = 0.003) and 3.424 (P = 0.001) times that in patients with more than 3 good habits, respectively. CONCLUSION: This empirical outcome shows that maintaining a good lifestyle improves T2DM management and patients' knowledge, motivation, and ability to use health information. Patients with longer disease duration, education, or good lifestyle habits had optimal HbA1c management than those in patients who did not. Thus, effective selfmanagement and precaution in daily life and improved health literacy of diabetic patients are necessary to increase the quality of T2DM care.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2002년도 춘계공동학술대회
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• pp.772-777
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• 2002

In this paper, economic screening procedures with dichotomous performance variable T and continuous screening variable X are considered when the rejected items are reprocessed. Two models are considered; normal and logistic models. It is assumed that X given T is normally distributed in the normal model, and $P(T=1{\mid}X=x)$ Is given by a logistic function in the logistic model. Profit models are constructed which involve four price/cost components; selling price, cost from an accepted nonconforming item, and reprocessing and inspectioncosts. Methods of finding the optimal screening procedures are presented and numerical examples are given.

• Asian-Australasian Journal of Animal Sciences
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• 제14권9호
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• pp.1326-1330
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• 2001

This study analyzed the lowest production cost and the greatest profit to be obtained from marketing hogs to determine the optimal operation scale for family-owned farrow-to-finish farms. Data were collected from 39 farrow-to-finish farms with 500 to 5,000 inventories for two consecutive years, and treated with GLM and quadratic regression models using the REG procedure. Analysis results indicated that farms capable of marketing 2,933 and 3,286 hogs annually had the lowest production cost and the greatest profit, respectively. Further analysis attributed the lowest production cost or the highest return in farms with an optimal scale of 3,000 to a higher survival rate of the herd, as well as lower expenses in veterinary medicine, labor, utilities and fuel, transportation, and depreciation. A similar feed conversion efficiency was observed for all the farms studied. Obviously, the cost efficiencies were associated with the economy of the operation scale of hog production until it reached 3,000 hogs marketed annually for a family-run unit. Beyond the optimal scale of 3,000 hogs, good stockmanship was more difficult to maintain and the herd management deteriorated as increasing mortality confirms. It is conclude that, unless advanced management is applied, the operation scale should not expand beyond 3,000 hogs.