• 품질경영학회지
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• 제38권4호
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• pp.540-548
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• 2010

We consider the problem of selecting the most profitable initial process mean and length of production cycle for manufacturing processes subject to a constant linear trend during the same cycle that varies after resetting the processes. Assuming that the quality characteristic of interest is normally distributed, the optimum initial process mean and the length of production cycle are jointly obtained by minimizing the expected loss per unit time. We assume that the quality loss function due to the deviation from the target value is quadratic and resetting loss is constant. We consider both cases of symmetric and asymmetric quality loss function. An illustrative example is given and sensitivity analysis performed.

• 한국컴퓨터정보학회논문지
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• 제19권12호
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• pp.171-175
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• 2014

NP-완전인 상자 포장 문제의 일종인 사탕수수 설탕 생산 문제에 대해, Gu$\acute{e}$ret et al.은 $O(m^4)$ 수행 복잡도의 선형계획법으로 해를 얻고자 하였다. 반면에, 본 논문에서는 사탕수수 설탕 생산 문제는 다항시간으로 해를 찾아가는 규칙이 존재한다는 가정하에, 최대 손실량을 가진 로트를 우선 생산하는 탐욕 규칙인 O(mlogm)의 다항시간 복잡도로 해를 구할 수 있는 알고리즘을 제안하였다. 제안된 방법은 설탕 함유량 손실 기울기를 내림차순으로 정렬한 후, 해당 슬롯 생산능력의 로트들을 선택하는 방법과 해당 슬롯에서 수명을 다하는 로트들과 마지막으로 선택된 로트들과 교환하는 방법을 적용하였다. 실험 결과, 제안된 알고리즘은 사탕수수 설탕 생산 문제에 대해 선형계획법의 $O(m^4)$를 O(mlogm) 으로 단축시키면서도 보다 좋은 결과를 얻었다.

• 산업경영시스템학회지
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• 제42권4호
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• pp.145-152
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• 2019

All machines deteriorate in performance over time. The phenomenon that causes such performance degradation is called deterioration. Due to the deterioration, the process mean of the machine shifts, process variance increases due to the expansion of separate interval, and the failure rate of the machine increases. The maintenance model is a matter of determining the timing of preventive maintenance that minimizes the total cost per wear between the relation to the increasing production cost and the decreasing maintenance cost. The essential requirement of this model is that the preventive maintenance cost is less than the failure maintenance cost. In the process mean shift model, determining the resetting timing due to increasing production costs is the same as the maintenance model. In determining the timing of machine adjustments, there are two differences between the models. First, the process mean shift model excludes failure from the model. This model is limited to the period during the operation of the machine. Second, in the maintenance model, the production cost is set as a general function of the operating time. But in the process mean shift model, the production cost is set as a probability functions associated with the product. In the production system, the maintenance cost of the equipment and the production cost due to the non-confirming items and the quality loss cost are always occurring simultaneously. So it is reasonable that the failure and process mean shift should be dealt with at the same time in determining the maintenance time. This study proposes a model that integrates both of them. In order to reflect the actual production system more accurately, this integrated model includes the items of process variance function and the loss function according to wear level.

• 농촌지도와개발
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• 제12권1호
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• pp.109-118
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• 2005

This study was carried out to identify the major characteristics of plug seedling farm's management. Thirty glasshouse farms were surveyed out of 42 farms that adopted plug seedling production technology in Korea. The major objectives of this survey were to determine the technical capability of the glasshouse farmers, and to analyze the significant differences in terms of production performance and management capabilities. The major results of the survey were as follows : 1) The production quantity of plug seedlings of the superior group was 43% higher than the inferior group. 2) The plug seedling loss rate of the superior roup was lower by 4% than the inferior group. 3) The income of superior group was 4.2 million Won per $1,000m^2$, while the income of the inferior group was only 0.45 million Won. 4) The cause of low production of grafted plug seedlings was primarily due to the lack of technical knowledge and skills. 5) The results indicated that the technical knowledge level and production skills of grafting plug seedling should be improved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.2046-2047
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• 2007

This paper is about the energy efficiency calculation of operating electric motors in production facilities. The most important 1st step to efficient operation of plants is the evaluation of the energy efficiency of the production facilities in that plant. Through this procedure, we can decide that which facilities i.e. induction motors, in this paper, should do maintenance or not. There are mainly 2 types of energy which are used in production facilities, the one is electric energy and the other is heat energy but in order to make calculation simple, in this paper, we are only focusing on electric energy, efficiency and energy loss of the electric motors under operation conditions. As a case study, we chose electric motors in a certain process in a production facilities, and calculated efficiency and loss by using measured data.

• Animal Bioscience
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• 제35권4호
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• pp.624-630
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• 2022

Objective: The aim of this study was to investigate the expression level of filaggrin-2 (FLG2) in correlation with drip loss. Methods: The muscle samples were randomly taken from a local meat supplier. Samples were taken from Longissimus lumborum muscles to evaluate the drip loss (n = 100). Five muscles per group (low and high drip loss) were selected to evaluate FLG2 mRNA and protein expression levels. Results: mRNA of FLG2 gene was not significantly different in pigs with different levels of drip loss (p>0.05). Statistical analysis revealed that FLG2 protein expression levels were significantly different between the drip loss groups. Western blot revealed that the high drip loss group had higher FLG2 protein expression level than the low drip loss group (p<0.001). Moreover, immunohistochemistry revealed the high signal intensity was on the muscle cell membrane and cytoplasm. Conclusion: FLG2 protein might play roles in drip loss of pork and will provide the basis for information to improving meat quality traits in pigs.

• The Korean Journal of Ecology
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• 제9권1호
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• pp.59-71
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• 1986

Net production, dead material increments were measured, and annual respiration loss was simulated through a year to determine the gross production at the Phragmites longivalvis, Carex scabrifolia and Zoysia sinica stand on Okryudeung, a sand bar of the Nagdong river estuary. The maximum live biomass for above-ground organs of the three stands occured in October, i.e., 1, 985, 744 and 1, 013g/m2, and belowground net productions were estimated to be 650, 440 and 412g/m2, respectively. Materials died or shedding from live aboveground organs during the growth season were estimated to be 167, 81 and 0 g/$m^2$. From the results of simulation, annual variation of respiratiion was primarily dependent on the annual variation of temperature through a year. For annual respiration loss in three stands, 21.893, 6.147 and 5.036kg $CO_2/m^2$ were calculated, respectively. Corresponding gross productions were 72, 203, 22, 109 and 19, 909kcal/$m^2$. Respiration of belowground organs corresponded to 65%, 66% and 37% of the total plant respiration, and annual respiration loss accounted for 85%, 78% and 71% of the annual gross production. In view of efficiency of solar energy utilization, 5.8%, 1.8% and 1.6% of incident light energy were converted to gross production of plants during a year. With incident light energy during the growth season from April to September, energy utilizations for net production were estimated to be 1.2%, 0.4% and 0.6% at the three stands.

• Journal of the Korean Data and Information Science Society
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• 제21권6호
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• pp.1051-1060
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• 2010

도금공정에서는 도금두께의 규격한계는 주어지지만 대부분의 경우 목표치는 주어지지 않는다. 목표치가 주어지지 않았을 때 일반적으로 규격의 중심점이 목표치로 사용된다. 하지만 공정능력치가 크다면 규격의 중심을 목표치로 사용하는 것은 총 손실비용면에서 최선의 선택이 아니다. 이 논문에서는 총 손실비용을 생산비용과 손실함수의 합으로 정의하였고 기대 총 손실비용을 최소화 하는 목표치를 제안하였다. 그리고 그때의 공정능력치의 감소가 미미한 것을 보였다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권4호
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• pp.534-540
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• 2003

This study was conducted to investigate the effect of supplementation of galacto-oligosaccharides (GOS) on methane emission, nutrient digestibility, energy utilization and blood metabolites by Holstein cows fed silages. In two sequential digestion and respiratory trials, two non-lactating Holstein cows were arranged to a balanced incomplete block design. Experimental diets consisted of two silage types; orchardgrass (Dactylis glomerata L.) based silage (OS), mixed silage (orchardgrass based silage and alfalfa (Medicago sativa L.) silage) (MS), while two GOS levels were without supplementation (0) and 2% of dry matter intake supplementation (2). Four combination diets were OS-0, OS-2, MS-0 and MS-2. Significant effects of silage types and GOS supplementation levels were not observed for DM and OM intake. Whereas the digestibility of OM, NDF and ADF was significantly (p<0.05) higher in cows fed OS with and without GOS compared cows fed MS diets. As percentage of GE intake, fecal energy loss for OS diets was significantly (p<0.05) declined than for MS diets. In contrast, cows fed MS diets had lower (p<0.05) urine energy loss as a proportion of GE intake compared to OS diets. Energy loss as CH4 and heat production was numerically increased when cows fed both OS and MS with GOS supplementation. Compared to OS, CH4 emission in cows fed MS was numerically decreased by 10.8 %. Methane conversion ratio (energy loss as CH4 per unit of GE intake) for OS-0, OS-2, MS-0 and MS-2 were 7.1, 7.2, 6.8 and 7.0, respectively. Plasma of glucose and urea-N concentration were significantly (p<0.05) elevated from 1 h to 6 h after feeding, otherwise total protein in plasma was declined (p<0.01) at 6 after feeding.

• 산업경영시스템학회지
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• 제43권3호
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• pp.95-100
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• 2020

Machines and facilities are physically or chemically degenerated by continuous usage. One of the results of this degeneration is the process mean shift. The representative type of the degeneration is wear of tool or machine. According to the increasing wear level, non-conforming products cost and quality loss cost are increasing simultaneously. Therefore a periodic preventive resetting the process is necessary. The total cost consists of three items: adjustment cost (or replacement cost), non-conforming cost due to product out of upper or lower limit specification, and quality loss cost due to difference from the process target value and the product characteristic value among the conforming products. In this case, the problem of determining the adjustment period or wear limit that minimizes the total cost is called the 'process mean shift' problem. It is assumed that both specifications are set and the wear level can be observed directly. In this study, we propose a new model integrating the quality loss cost, process variance, and production volume, which has been conducted in different fields in previous studies. In particular, for the change in production volume according to the increasing in wear level, we propose a generalized production quantity function g(w). This function can be applied to most processes and we fitted the g(w) to the model. The objective equation of this model is the total cost per unit wear, and the determining variables are the wear limit and initial process setting position that minimize the objective equation.