Optimal Design of a Steel Box Girder Bridge Considering Life Cycle Cost

신영석,박장호,하동호 대한토목학회 2009 KSCE JOURNAL OF CIVIL ENGINEERING Vol.13 No.6

Life cycle cost has come to occupy an important position in the design of bridges and many researchers have made an effort to develop cost models to take life cycle cost into account rationally. This paper derived load carrying capacity curves including repair and rehabilitation histories for members of bridge and performed optimal design of a steel box girder bridge consisting of concrete deck, steel box girders and piers considering life cycle cost. Total life cycle cost for the service life is calculated as sum of initial cost, damage cost, maintenance cost, repair and rehabilitation cost, and user cost. The optimization method is applied to the design of bridge members with minimal value. The objective function is set to the annual cost, which is obtained by dividing the total life cycle cost by the service life, and constraints are formulated on the basis of Korean Standards. The optimal design is performed for various service lives and the effect of design factors is investigated. The results suggest that although it is not easy to consider various cost factors accurately, those cost factors which are affected by the various environmental conditions and uncertainties should be considered. Life cycle cost has come to occupy an important position in the design of bridges and many researchers have made an effort to develop cost models to take life cycle cost into account rationally. This paper derived load carrying capacity curves including repair and rehabilitation histories for members of bridge and performed optimal design of a steel box girder bridge consisting of concrete deck, steel box girders and piers considering life cycle cost. Total life cycle cost for the service life is calculated as sum of initial cost, damage cost, maintenance cost, repair and rehabilitation cost, and user cost. The optimization method is applied to the design of bridge members with minimal value. The objective function is set to the annual cost, which is obtained by dividing the total life cycle cost by the service life, and constraints are formulated on the basis of Korean Standards. The optimal design is performed for various service lives and the effect of design factors is investigated. The results suggest that although it is not easy to consider various cost factors accurately, those cost factors which are affected by the various environmental conditions and uncertainties should be considered.

연구개발 단계에서 Modeling & Simulation을 활용한 무기체계 수명주기비용 산출 방안 연구

권면재(Myeon-Jae Kwon),박영민(Young-Min Park),계영진(Young-Gin Kye),신주환(Ju-Hwan Shin),조현주(Hyun-Ju Cho) 한국산학기술학회 2022 한국산학기술학회논문지 Vol.23 No.3

최근 방위사업에서는 무기체계의 수명주기 전 단계에서 효율성과 연계성을 강화하고 전체 최적화를 달성하고자 총수명주기체계관리 정책을 확대 적용하고 있다. 이로 인해 전 수명주기 단계를 관리하기 위한 수명주기관리계획서의 작성이 요구되며, 수명주기 간 무기체계의 경제적인 운영을 위해 지속적으로 수명주기비용을 산출하고 관리해야 한다. 수명주기비용의 절감 기회는 대부분 연구개발 단계에 존재하므로, 연구개발 단계에서 수명주기비용에 대한 충분한 분석 및 검토가 이루어져야 한다. 본 연구에서는 연구개발 단계에서 수명주기비용 M&S 도구를 활용하여 수명주기비용을 추정하였으며, 수명주기비용 구조를 모델링하고 각 비용 요소별 산출 방안을 제시하였다. 또한, 추정된 수명주기비용의 타당성을 검증하기 위해 공학적 분석 방법에 의해 산출된 수명주기비용과 비교 분석을 수행하였다. 본 연구 결과는 무기체계 수명주기비용 관리의 기초자료로 활용될 것으로 기대된다. 본 연구에서 반영하지 못했던 몇몇 비용요소에 대해 추후 소요군의 실 데이터를 확보하고, 관련 규정 및 지침이 마련되면 후속연구에 포함하여 보다 정확한 수명주기비용을 산출할 예정이다. Recently, the Total Life Cycle System Management policy is being extended to the defense industry to strengthen the efficiency and connectivity and achieve optimization throughout the life cycle of weapon systems. As a result, it is required to prepare a Life Cycle Sustainment Plan to manage the entire life cycle. In addition, Life Cycle Cost must also be continuously calculated and managed for the economical operation of a weapon system. Since most of the opportunities to reduce the Life Cycle Cost exist in the R&D phase, sufficient analysis and review of the Life Cycle Cost should be conducted in the R&D phase. This study estimated the Life Cycle Cost using the M&S tool in the R&D stage. The Life Cycle Cost structure was modeled and a method for calculating each cost element was presented. Also, a comparative analysis was performed with the Life Cycle Cost calculated by the engineering analysis method to verify the validity of the estimated Life Cycle Cost. The results of this study are expected to be used as basic data for life cycle cost management of weapon systems. In future, when some cost elements that were not reflected in this study are obtained from the military and related regulations and guidelines are prepared, they will be reflected in the follow-up studies.

기업수명주기가 판매관리비의 비대칭적 원가행태에 미치는 영향

고영우,권수영,황문호 韓國公認會計士會 2009 회계·세무와 감사 연구 Vol.49 No.-

과거 연구에 의하면, 매출액 증가시의 판매관리비 변동폭이 매출액 감소시의 판매관리비 변동폭보다 크게 나타나는 판매관리비의 하방경직적 원가행태가 관찰되었다. 본 연구는 이러한 선행연구 결과에 기초하여, 판매관리비의 하방경직성이 기업의 수명주기에 따라 차별적으로 나타나는지를 분석한다. 구체적으로, 성장기의 기업은 시장을 확대시키려는 전략적 목표에 따라 투자 및 판매관리비의 지출을 꾸준히 증가시키는 경향이 있어 하방경직적인 원가행태가 두드러질 것으로 예상된다. 반면에, 성숙기나 쇠퇴기의 기업은 이익을 극대화시키고자 원가절감 전략을 펴거나 기정자원에 대한 투자를 감소시키는 경향이 있어 판매관리비의 하방경직성은 약화되거나 나타나지 않을 것으로 보인다. 1989년부터 2007년에 걸쳐 거래소에 상장된 7,420 기업-년도를 대상으로 위 가설을 검증한 결과, 예측한 바와 같이 성장기의 기업에서는 매출액 증가시의 판매관리비 증가폭이 매출액 감소시의 판매관리비 감소폭에 비해 2배 가까이 높은 하방경직성이 나타났으나, 쇠퇴기의 기업에서는 오히려 매출액 감소시의 판매관리비 감소폭이 매출액 증가시의 판매관리비 증가폭보다 큰 상방경직성이 발견되었다. 이는 판매관리비의 하방경직성이 성장기 기업에서 나타나는 차별적 속성임을 보여주는 한편 기업수명주기가 판매관리비의 비대칭적 원가행태를 결정하는 주요 요인임을 나타내고 있다. 본 연구는 원가의 비대칭성 존재 여부를 분석한 선행연구들과 달리, 원가의 비대칭성에 대한 새로운 원인을 기업의 전략적 목표와 연계하여 제시하고 있다는 점에서 차별적 의의를 가지는 것으로 판단된다. Previous studies demonstrate that costs decrease less when activities fall than they increase when activities rise by an equivalent amount, indicating that selling, general and administrative (SG&A) costs are sticky(Noreen and Soderstrom 1994, 1997; Cooper and Kaplan 1998; Anderson et al. 2003; Ahn et al. 2004; Lee et al. 2004). Based on these findings, we examine whether the stickiness of SG&A costs varies with firm life cycle. Anderson et al.(2003) suggest that the stickiness of SG&A costs occurs if managers decide to retain unutilized resources rather than incur adjustment costs(ex. severance pay for dismissed employee, search and training costs for new employee) when volume declines. This reasoning implies that the stickiness of SG&A costs is eventually determined by managers' consideration of corporate strategies they pursue. Govindarajan and Shank(1993) suggest three strategies(mission) that a business unit can adopt. They are build, hold, and harvest. Build strategy implies a goal of increased market share, even at the expense of short-term earnings and cash flow. While harvest strategy pursues a goal of maximizing short-term earnings and cash flow even at the expense of market share. Since the acquisition of market share is highly valued in early life cycle stages(Anthony and Ramesh 1992), it is reasonable to expect the manager of growth firm will adopt build strategy, . To the contrary, the manager of decline firm will adopt harvest strategy, because there are few chances to expand their market. Business firms are evolving entities and firm life cycles are distinctive phases that result from change in external/internal factors, which arise from strategic activities undertaken by the firm. This study anticipates that the different strategy of each life cycle will induce the different asymmetrical behavior of SG&A costs. We expect that firms at the growth stage continuously spend investing and SG&A expenditures in order to pursue the strategy to expand a market so that the property of sticky costs are more pronounced at the growth stage. On the other hand, firms at the maturity/decline stages may take the harvest strategy to maximize their profits and reduce their expenditures on investments. Thus, the tendency of sticky costs is likely to be attenuated for firms at the maturity/decline stages. Based on life cycle indicators used in Anthony and Ramesh(1992), this paper classifies samples into GROWTH, MATURE and DECLINE life cycle stages. The life cycle indicators are sales growth rate, capital expenditures, firm age, and market-to-book ratio. We replace dividend ratio used by Anthony and Ramesh(1992) with market-to-book ratio. This is due to the difference in the dividend policy of Korea is quite different from that of U.S(Kwon 1996), while the market-to-book ratio is believed to be a stable proxy reflecting future profitability of a company(Bens et al. 2002) over the countries. For about 71% of the sample, life cycle stage does not change from year t to year t+1, which means that the life cycle measure is valid. Our sample is obtained from the Kis-Value and TS-2000, listed on Korean Stock Exchange from 1989 to 2007. The constraints of sample selection procedures yield a final sample of 7,420 firm-year observations. To test our hypotheses, we adopt the empirical model of Anderson et al(2003). The model enables measurement of the SG&A response to contemporaneous changes in sales revenue. We add dummy variables reflecting the life cycles to the model. For firms at the growth stage, the rate of increase in SG&A costs with an increase in sales is almost twice as much as the rate of decrease in SG&A costs with a decrease in sales. SG&A costs of growth firm increase on average 0.58% per 1% increase in sales but 0.28% decrease per 1% decrease in sales. On the other hand, for firms at the decline stage, the rate of decrease in SG&A costs with an decrease in sales is greater than the rate of increase in SG&A costs with an increase in sales. That is SG&A costs of decline firm increase on average 0.34% per 1% increase in sales but -0.46% decrease per 1% decrease in sales. These results indicate that firm life cycle is an important factor in determining the asymmetric behavior of SG&A costs with the change in sales.

Failure Cost와 Life Cycle Cost를 고려한 연속시스템에 대한 최적 장치 선택에 관한 연구

진상화,김용하,송희열,여영구,김인원 한국안전학회 2004 한국안전학회지 Vol.19 No.4

In this study, the required life cycle cost is evaluated in consideration of the equipment's availability during its life cycle. In order to meet the maximum availability required by the process, the failure cost and life cycle cost is assessed, The optimal equipment selection method is presented according to the analysis of the failure cost and life cycle cost. For the systems in which equipments are connected serially, the optimal equipments are selected by minimizing the life cycle cost and satisfying the required system availability goal. In addition, the selection methods and life cycle cost are analyzed according to the cost variation of the equipment. By using the life cycle evaluation procedure, the failure cost and maintenance cost needed during the life cycle of the equipment can be presented.

원가관리 집중편차와 원가관리활동 그리고 성과간의 관계

김달곤,김순기 대한경영학회 2004 大韓經營學會誌 Vol.17 No.3

Traditional cost management systems have focused primarily on recurring conversion costs. Life-cycle management focuses on those activities that occur prior to production to ensure the lowest total life-cycle cost. Previous studies show that about 85 to 90 percent of a product's life-cycle cost is determined by decisions made early in the cycle. The supposition of cost management model is that investment in prior to production activities will bring rewards from reduced costs. In this study, the degree of cost management deviation is conceptualized. This means a deviation between the ideal and present ranking in the likelihood of cost management of each life-cycle stage. This study analysed that the effect of its deviation on cost management activity and performance variables. However, there are no difference in these variables. The major reason is that most of companies are the design ability is insufficient. Therefore, the companies must endeavor in order to raise a design ability. Traditional cost management systems have focused primarily on recurring conversion costs. Life-cycle management focuses on those activities that occur prior to production to ensure the lowest total life-cycle cost. Previous studies show that about 85 to 90 percent of a product's life-cycle cost is determined by decisions made early in the cycle. The supposition of cost management model is that investment in prior to production activities will bring rewards from reduced costs. In this study, the degree of cost management deviation is conceptualized. This means a deviation between the ideal and present ranking in the likelihood of cost management of each life-cycle stage. This study analysed that the effect of its deviation on cost management activity and performance variables. However, there are no difference in these variables. The major reason is that most of companies are the design ability is insufficient. There

기업수명주기와 자본비용

하석태 ( Ha Seok-tae ) 한국세무회계학회 2020 세무회계연구 Vol.0 No.65

[연구목적] 본 연구는 현금흐름패턴에 따른 기업수명주기 구분의 유용성을 검증하기 위하여, 자본조달비용 측면에서 기업수명주기에 따라 기업의 자본비용에 차이가 있는지를 분석 하였다. [연구방법] 기업수명주기에 관한 선행연구를 토대로 성숙기의 기업이 다른 기업수명주기의 기업보다 자본비용이 낮을 것으로 예상하고, 회귀분석을 통하여 성숙기의 기업이 자본비용에 미치는 영향을 분석하였다. 여기에서 자본비용은 채권자 관점에서 타인자본비용과 주주 관점 에서 자기자본비용으로 측정하였다. [연구결과] 분석결과 성숙기의 기업은 다른 기업수명주기의 기업들보다 타인자본비용과 자기자본비용이 낮은 것으로 나타났다. 이는 다른 기업수명주기 여부더미 변수를 포함한 연구 모형에서도 성숙기의 기업은 다른 기업수명주기의 기업보다 타인자본비용과 자기자본비용 이 낮은 것으로 나타났고, 이익잉여금을 포함한 연구모형에서도 성숙기의 기업은 다른 기업 수명주기의 기업보다 타인자본비용과 자기자본비용이 낮은 것으로 나타났다. 이는 성숙기의 기업이 다른 기업수명주기의 기업보다 투자자들에게 유용한 회계정보를 제공함으로써 자본 비용의 증가를 발생시킬 수 있는 정보위험이 낮아져 나타난 결과로 보인다. [연구의 시사점] 이상의 결과는 현금흐름패턴에 따른 기업수명주기의 구분이 채권자와 주 주들에게 기업의 정보위험을 평가할 수 있는 정보로서 유용함을 시사한다. [Purpose] This study investigates whether there is a difference in the cost of capital at firms according to the firm life cycle to verify the usefulness of the firm life cycle classification measured by cash flow pattern. [Methodology] We expected that firm in the mature stage has a lower cost of capital than firms in other firm life cycle stages, based on prior research on the firm life cycle. And the effect of firms in the mature stage on the cost of capital has analyzed through regression analysis. We have measured the cost of debt capital(the viewpoint of the creditor) and the cost of equity capital(the perspective of the shareholder). [Findings] As a result of the analysis, we find that the cost of debt and equity capital of firms in the mature stage has a lower others’ cost of capital. Also, results at the research model, including the firm life cycle variables or retained earnings variable, show that firms in the mature stage a lower others’ cost of capital. It means that the cost of debt and equity capital in the mature stage is lower than other firm life cycle stages. These results mean that firms in the mature stage have a higher quality of accounting information and higher continuity of income than firms in other firm life cycles, thus lowering the risk of information lead to decrease costs of capital. [Implications] The results suggest that the firm life cycle is useful for creditors and shareholders to evaluate the firm’s information risk.

교량의 생애주기비용 최적설계

박장호,신영석 한국안전학회 2010 한국안전학회지 Vol.25 No.6

The importance of the life cycle cost (LCC) analysis for bridges has been recognized over the last decade. However, it is difficult to predict LCC precisely since the costs occurring throughout the service life of the bridge depend on various parameters such as design, construction, maintenance, and environmental conditions. This paper presents a methodology for the optimal life cycle cost design of a bridge. Total LCC for the service life is calculated as the sum of initial cost, damage cost, maintenance cost, repair and rehabilitation cost, user cost, and disposal cost. The optimization method is applied to design of a bridge structure with minimal cost, in which the objective function is set to LCC and constraints are formulated on the basis of Korean Bridge Design Code. Initial cost is calculated based on standard costs of the Korea Construction Price Index and damage cost on damage probabilities to consider the uncertainty of load and resistance. Repair and rehabilitation cost is determined using load carrying capacity curves and user cost includes traffic operation costs and time delay costs. The optimal life cycle cost design of a bridge is performed and the effects of parameters are investigated

생애 신뢰성에 기초한 강교의 LCC최적설계

이광민(Lee Kwang-Min),조효남(Cho Hyo-Nam),차철준(Cha Cheol-Jun),김성헌(Kim Seong-Hun) 대한토목학회 2006 대한토목학회논문집 A Vol.26 No.1A

This paper presents a practical and realistic Life-Cycle Cost (LCC) optimum design methodology of steel bridges considering time effect of bridge reliability under environmental stressors such as corrosion and heavy truck traffics. The LCC functions considered in the LCC optimization consist of initial cost, expected life-cycle maintenance cost and expected life-cycle rehabilitation costs including repair/replacement costs, loss of contents or fatality and injury losses, road user costs, and indirect socio-economic losses. For the assessment of the life-cycle rehabilitation costs, the annual probability of failure which depends upon the prior and updated load and resistance histories should be accounted for. For the purpose, Nowak live load model and a modified corrosion propagation model considering corrosion initiation, corrosion rate, and repainting effect are adopted in this study. The proposed methodology is applied to the LCC optimum design problem of an actual steel box girder bridge with 3 continuous spans (40 m+50 m+40 m=130 m), and various sensitivity analyses of types of steel, local corrosion environments, average daily traffic volume, and discount rates are performed to investigate the effects of various design parameters and conditions on the LCC-effectiveness. From the numerical investigation, it has been observed that local corrosion environments and the number of truck traffics significantly influence the LCC-effective optimum design of steel bridges, and thus realized that these conditions should be considered as crucial parameters for the optimum LCC-effective design. 본 논문에서는 생애주기동안 발생하는 부식이나 일평균교통량 및 중차량의 통행량와 같은 사용환경에 의존하는 강교의 생애신뢰성에 기초한 생애주기비용(Life-Cycle Cost: 이하 LCC) 최적설계 방법론을 제안하였다. 강교 최적설계를 위한 LCC는 초기비용, 생애주기 기대유지관리비용, 생애주기 기대직접복구비용과 인적 혹은 물적손실비용, 도로이용자비용, 그리고 사회­경제 손실비용을 포함하는 간접복구비용을 현재가치의 합으로 정식화하였다. 이러한 LCC비용항목 중에서 생애주기 복구비용의 산정을 위해서는 하중과 저항이력에 의존하는 누적손상확률로부터 산정되는 연피손확률이 고려되어야한다. 이를 위해 본 논문에서는 Nowak의 활하중 모델(1993)과 부식개시, 부식률, 그리고 재도장영향을 고려한 수정된 부식모델을 제안하였다. 이와같이 본 연구에서 제안된 LCC 최적설계 방법론은 3 경간연속(40 m+50 m+40 m=130 m)의 실제 강박스거더교에 적용되었고, 강재종류, 부식환경, 교통량 및 할인율에 따른 LCC의 효율성에 대해 비교ㆍ고찰하였다. 적용예를 통해 부식환경, 일평균교통량, 그리고 중차량의 통행량, 할인율 등은 강교 LCC최적설계에 매우 중요한 영향을 미칠 수 있음을 알 수 있었으며, 이러한 교량의 사용환경인자들은 경우에 따라 LCC 최적설계에 대한 주요 변수로 고려되어야 할 것으로 판단된다.

Applying a Life-Cycle Assessment to the Ultra Pure Water Process of Semiconductor Manufacturing

Tien, Shiaw-Wen,Chung, Yi-Chan,Tsai, Chih-Hung,Yang, Yung-Kuang,Wu, Min-Chi The Korean Society for Quality Management 2005 The Asian Journal on Quality Vol.6 No.3

A life-cycle assessment (LCA) is based on the attention given to the environmental protection and concerning the possible impact while producing, making, and consuming products. It includes all environmental concerns and the potential impact of a product's life cycle from raw material procurement, manufacturing, usage, and disposal (that is, from cradle to grave). This study assesses the environmental impact of the ultra pure water process of semiconductor manufacturing by a life-cycle assessment in order to point out the heavy environmental impact process for industry when attempting a balanced point between production and environmental protection. The main purpose of this research is studying the development and application of this technology by setting the ultra pure water of semiconductor manufacturing as a target. We evaluate the environmental impact of the Precoat filter process and the Cation/Anion (C/A) filter process of an ultra pure water manufacturing process. The difference is filter material used produces different water quality and waste material, and has a significant, different environmental influence. Finally, we calculate the cost by engineering economics so as to analyze deeply the minimized environmental impact and suitable process that can be accepted by industry. The structure of this study is mainly combined with a life-cycle assessment by implementing analysis software, using SimaPro as a tool. We clearly understand the environmental impact of ultra pure water of semiconductor used and provide a promotion alternative to the heavy environmental impact items by calculating the environmental impact during a life cycle. At the same time, we specify the cost of reducing the environmental impact by a life-cycle cost analysis.

강교의 도장방식에 따른 안전수명간 생애주기비용분석

조선규,한상철,김은겸 한국산업안전학회 2002 한국안전학회지 Vol.17 No.2

Life Cycle Cost analysis technique is introduced to evaluate cost-effectiveness of two paint systems of steel bridges. The systems are a conventional paint system and a galvanized paint system. The all costs during safe life such as initial cost, repainting costs, disposal costs are considered for the life cycle cost analysis. The NIST model is used and BridgeLOC 1.0 developed by the NIST is utilized as the life cycle cost analysis tool. It is concluded that, in spite of expensive initial cost, the durable paints system may be cost-effective compared with conventional paint system.