• 융합정보논문지
• /
• 제11권3호
• /
• pp.125-131
• /
• 2021

모든 장비는 지속적인 사용에 의해 공정의 생산성과 경제성은 감소한다. 그러므로 일정 시점에서는 공정평균이동 문제라는 설비에 대한 예방보전이 필요하다. 설비의 보전시기를 결정함에 있어, 우리는 기존 연구에서 부분적으로 진행되어 온 보전모형들을 확장하고 통합함으로써 다양한 상황이 발생하는 생산 현장을 반영한 보전모형을 제시하고자 한다. 이를 구현하기 위해 제품규격은 상하한의 양쪽을 설정했으며, 적합품에 대해 품질손실함수를 도입했다. 마모수준에 대한 공정분산은 상수가 아닌 함수로 설정했으며, 특히 제품생산량과 보전비용에 있어서는 마모수준에 대한 함수를 개발하여 적용했다. 이로써 본 연구는 현장의 다양한 공정에 대부분 적용할 수 있는 보전모형이 될 것으로 생각한다. 추후 연구에서는 보전모형을 구성하는 부적합비용, 품질손실비용, 보전비용에 더하여 제품판매로 인한 수익 항목을 추가한 전체 수익 최대화 문제로 전개할 수 있을 것이며, 크게는 본 연구의 모형에 고장률을 도입한 보전모형으로의 확장도 생각해 볼 수 있을 것이다.

• 산업경영시스템학회지
• /
• 제44권1호
• /
• pp.45-50
• /
• 2021

Machines and facilities are physically or chemically degenerated by continuous usage. The representative type of the degeneration is the wearing of tools, which results in the process mean shift. According to the increasing wear level, non-conforming products cost and quality loss cost are increasing simultaneously. Therefore, a preventive maintenance is necessary at some point. The problem of determining the maintenance period (or wear limit) which minimizes the total cost is called the 'process mean shift problem'. The total cost includes three items: maintenance cost (or adjustment cost), non-conforming cost due to the non-conforming products, and quality loss cost due to the difference between the process target value and the product characteristic value among the conforming products. In this study, we set the production volume as a decreasing function rather than a constant. Also we treat the process variance as a function to the increasing wear rather than a constant. To the quality loss function, we adopted the Cpm+, which is the left and right asymmetric process capability index based on the process target value. These can more reflect the production site. In this study, we presented a more extensive maintenance model compared to previous studies, by integrating the items mentioned above. The objective equation of this model is the total cost per unit wear. The determining variables are the wear limit and the initial process setting position that minimize the objective equation.

• 품질경영학회지
• /
• 제21권1호
• /
• pp.199-213
• /
• 1993

The function-cost matrix table is not constant, but can be changed by many factors including equipment capacity, level of production technique, fluctuation of production volume, and the continuous development of products. Such changes would give the VE analysists additional work burden. By using computer. in this study, much of the time and effort of the function evaluation could be saved, and the efficiency of the analysis could also be enhanced. The application of the function evaluation data of R Company, as a case analysis, to the function evaluation computer program developed in this study resulted in the faster management of function-cost matrix table and function evaluation.

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

• 영어영문학
• /
• 제56권5호
• /
• pp.973-998
• /
• 2010

This paper aims at assessing the significance of Lyrical Ballads of 1798, the agreed inaugurator of English Romanticism, in terms of such key concepts as poetic "experiments," "conversation," and the authorial function. The 1798 volume marks an interesting incidence in which an author with no tangible substantiality can wield his authorial function over his works. The volume is signed without the named proper noun-its author is neither William Wordsworth nor Samuel Taylor Coleridge. The figure of the author in this case is realized by the poems he writes; he produces, and is produced by, his works-a fact that constitutes part of the poetic experiments manifested in the Advertisement. Working under this reciprocal production, the Author of the 1798 volume and his poems are collectively aiming at establishing a new class of poetry and an interpretive community. The notion of "conversation" is a key element in the thematic, stylistic ties among individual poems. Poems of the 1798 volume effect multi-layered, "blended" voices. Readers are expected to draw out the topological interweaving among poems through the practices of dialogic reading. In this light, the sequential necessity of "The Rime" and "Tintern Abbey" should be emphasized. They are stitched together in a logic of textual placement and the transition from one to the other is never arbitrary. Most of all, they are working under the same authorial function, complementing each other, and addressing the same poetic project in different textual locations. As an inaugural work of English Romanticism, Lyrical Ballads of 1798 in fact makes so many things happen and yet again anticipates something yet to come with elusiveness. The value of this poetic experiments should be judged not only by what is claimed in it, but what it sets out to do and "how far" it will be performed, as implied in the Advertisement. The efficacy of the volume, more than anything else, is dependent upon the performative power of words.

• 한국태양에너지학회 논문집
• /
• 제28권5호
• /
• pp.1-7
• /
• 2008

Flashed steam system is one of the important geothermal power production methods. In this paper, optimum operations and performances of single and double flash systems are presented. It is shown that double flash system can produce about 26.5% more power than single flash system. Temperature of geothermal water($T_R$) is the most important parameter in the geothermal system. Optimum single and double flash temperatures and net power produced with these optimum conditions are expressed as a function of $T_R$ in this study. Thus net power output from geothermal resources can be estimated with the results of this work. Condenser Temperature($T_{con}$) is also important and the net power production can be shown as a function of ($T_R-T_{con}$. Volume flow rate per unit power is also to be considered as the condenser temperature decreases.

• 대한수의학회지
• /
• 제42권3호
• /
• pp.299-308
• /
• 2002

The purpose of this morphometric study was to obtain detailed quantitative information on all cell types in the testis interstitium of Korean ring-necked pheasants combined with data on changes in the steroidogenic function of the testis during the breeding and nonbreeding seasons. Animals collected during the breeding season, testis weights, sperm production, serum testosterone levels, leuteinizing hormone-stimulated testosterone secretion, and the length of the seminiferous tubules were significantly (p < 0.05) increased as compared to the nonbreeding season. Seminiferous tubules occupied 93.25% of testis volume in the breeding season. Leydig cells constituted 0.82% of the testicular volume. The mean volume of an Leydig cell was $1039{\mu}m^3$, and each testis contained about 24.53 million Leydig cells. Testes of the pheasants during the nonbreeding season displayed a 98% reduction in testis volume that was associated with a decrease in the absolute volume of seminiferous tubules (98% reduction), tubular lumen(100%), interstitium(90%), blood vessels(84%), lymphatic spaces(97%), Leydig cells(79%), mesenchymal cells(51%), and myoid cells(61%). The number of Leydig cells, mesenchymal cells, myoid cells per testis in the breeding season was higher (p < 0.05) than in the nonbreeding season. Although the average volume of a Leydig cell was 74% lower in the nonbreeding season, the average volume of a myoid and mesenchymal cell remained unchanged. These results demonstrate that there are a striking differences in the testicular structure of the Korean ring-necked pheasant in the breeding and nonbreeding seasons. Every structural parameter of the Leydig cell was pasitively correlated with both serum and LH-stimulated secretion concentrations of testosterone. Correlation of changes in hormonal status with morphometric alterations of all Leydig cell suggests that the Korean-ring necked pheasant may be used as a model to study structure-function relations in the avian testis.

• Journal of Forest and Environmental Science
• /
• 제28권1호
• /
• pp.30-36
• /
• 2012

The total yield of Pinus koraiensis stands was reviewed along forest function by using goal programming, which is one of the operations research techniques. The 4 kinds of management goals are set to identify timber production in the Research Forest of Kangwon National University. As a result, scenario 1 was estimated the best timber production over 2,073 ha area and also 588 ha in the third quarter was showed the most timber harvest. The rate of timber harvest was separated by 10 to 50 percent in non-timber forest function in the scenario 1 and that model was applied to the Research Forest of Kangwon National University. The structure of the area and volume is showed to be balanced quarterly when rate of timber harvest at 10 to 20 percent.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
• /
• pp.137-142
• /
• 2001

Since recent production system becomes that of the small quantity, large volume with high quality production, accurate and high speed inspection system is required. In such situation, noncontact 3D measurement system which utilized CCD cameras is useful technique in terms of system cost, speed of data acquisition, measuring accuracy and application. However, it has low accuracy compared with contact 3D measurement system because of the camera distortion, non uniformity of laser distribution and so on. For those reasons, in this paper precision enhancement method is studied considering radial camera distortion, and laser distribution. A distortion correction method is applied even to the standard lens. The laser slit beam trajectory is determined by 3 method: based of the Gaussian function signal approximation, the median method, the center of gravity method and the peak point of the Gaussian function method.

• 대한조선학회논문집
• /
• 제57권1호
• /
• pp.45-51
• /
• 2020

In this study, we developed an allocation optimization system for supply chain management in the shipbuilding and offshore construction industry. Supply chain operation is a way of operating manufacturing company responsible for the procurement of outfitting parts. The method about how to allocate the manufacturing volume to each partner company includes important decisions. According to the allocation method, the stability of the material supplied to the final installation process is guaranteed. We improved the allocation method that was previously decided by the person in charge. Based on the optimization engine, a system is developed that can automatically allocate the production volume. For optimization model configuration, factors affecting the volume allocation were analyzed and modeled as constraint factors. A target function is defined to minimize the difference in the load variance of each partner company. In order to use the same type of volume allocation engine for various outfitting products, the amount of work done by the partner company was standardized. We developed an engine that can allocate the same production load of each production partner. Using this engine, the operating system was developed and applied to the actual offshore project. It has been confirmed that the work load variance of suppliers can be maintained uniformly using the optimization engine rather than manual method. By this system, we stabilize the manufacturing process of partner suppliers.