• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.1498-1502
• /
• 2007

본 연구에서는 격자기반의 레이더강우 등과 같은 향후 제공될 분포형 강수를 활용하기 위해 국내 유역에서 GIS와 연계한 물리적 기반의 수문학적 분포형모형의 적용성을 검토하고, 향후 저수지 유입량 예측을 위해 수자원공사 현업에서 실시간 물관리에 사용하고 있는 개념적기반의 집중형모형인 Kwater홍수분석모형과 실시간 홍수조절을 목적으로 미국 오클라호마대학의 백스터교 수측에서 개발된 물리적기반의 분포형모형인 Vflo모형을 이용하여 낙동강권역의 남강댐유역을 대상으로 유출해석을 수행하여 양 모형의 구조적인 장단점 등을 비교분석하였다. 입력이 되는 분포형 강우는 지상관측강우, 레이더추정강우를 적용하였고, GIS수문매개변수를 ArcGIS 및 ArcView를 활용하여 DEM, 토지피복도, 토양도 등의 기본 GIS자료들로 부터 추출, 물리적기반의 분포형모형(Vflo)의 입력인자로 사용하여 모형의 초기설정을 향상시켰다. 모형에서 계산된 방법이 물리성을 구비하여 타당한 매개변수의 값으로 현실의 유출량을 재현할 수 있는지를 실제 유역 규모의 스케일로 검증하고자 하였으며 홍수기 댐유역의 유출모의를 위한 모형의 장단점을 파악하고 분포형모형의 향후 실용화 가능성을 검토하였다. 모형 수행 결과, 모형보정은 물리적기반의 분포형모형인 Vflo모형이 집중형모형인 Kwater모형에 비하여 GIS를 이용하여 지형공간 자료와 토양, 토지피복과 같은 물리적 특성을 사용한 모형의 초기 설정을 향상시킴에 따라 평균적으로 첨두유량에서 $\pm254\;cms$, 유출량에서 $\pm14\;mm$, 첨두도달 시간차에서 $\pm15$분 이내의 정확도 향상을 가져왔다. 물리적 기반의 분포형모형인 Vflo모형은 남강댐유역 대다수 관측소에서 별다른 매개변수의 보정없이도 합리적이고 유용한 결과를 보여주었다. 이러한 결과는 GIS와 연계한 물리적기반의 분포형모형이 향후 돌발홍수나 게릴라성 집중호우 등의 악기상에 대응하여 레이더 등의 정확하고 신뢰할만한 강우예측이 입력자료로 생성되었을 때 다목적댐 저수지 운영에 있어서 리드타임을 충분히 확보하여 안정적이고 예측가능한 홍수조절을 수행할 수 있는 가능성을 보여주었다고 사료된다.

• Journal of the Korea Safety Management & Science
• /
• v.15 no.1
• /
• pp.217-229
• /
• 2013

As customers' demands for diversified small-quantity products have been increased, there have been great efforts for a firm to respond to customers' demands flexibly and minimize the cost of inventory at the same time. To achieve that goal, in SCM perspective, many firms have tried to control the inventory efficiently. We present an mathematical model to determine the near optimal (s, S) policy of the supply chain, composed of multi suppliers, a warehouse and multi retailers. (s, S) policy is to order the quantity up to target inventory level when inventory level falls below the reorder point. But it is difficult to analyze inventory level because it is varied with stochastic demand of customers. To reflect stochastic demand of customers in our model, we do the analyses in the following order. First, the analysis of inventory in retailers is done at the mathematical model that we present. Then, the analysis of demand pattern in a warehouse is performed as the inventory of a warehouse is much effected by retailers' order. After that, the analysis of inventory in a warehouse is followed. Finally, the integrated mathematical model is presented. It is not easy to get the solution of the mathematical model, because it includes many stochastic factors. Thus, we get the solutions after the stochastic demand is approximated, then they are verified by the simulations.

• Journal of Digital Convergence
• /
• v.11 no.3
• /
• pp.175-180
• /
• 2013

To compete global marketplace, many firms are adopting product families to increase variety, satisfy customer requirements, shorten lead-times and reduce costs. The key to a successful product family is the platform from which it is derived. When designing product families, it is important to resolve the tradeoff between product commonality and distinctiveness. To measure the commonality within a product family, it is necessary to develop the commonality index. It utilizes different parameters such as the number of common components, their cost, their manufacturing processes and so on. This paper present a new product family assessment index using the benchmarking method and considering environmental performance called green product family index(GPFI). Through the comparison analysis between some previous developed commonality indices and GPFI, we verify the suitability and effectiveness. Eventually, the proposed a new green product family assessment index can be helpful to design and develop the environmentally conscious product families.

• Journal of Digital Convergence
• /
• v.12 no.5
• /
• pp.125-130
• /
• 2014

The competitiveness in today's global market forces many companies to develop families of products to provide enough variety for the marketplace. The challenge when designing a product family is in resolving the tradeoff between product commonality and distinctiveness. Simultaneously it is necessary to consider environmental performance to design a product family as well as to shorten lead-times, improve quality and reduce costs. This paper proposes a metaheuristic algorithm based redesign methodology for green product family considering environmental performance. The proposed method uses a genetic algorithm as metaheuristic algorithm and green product family index (GPFI) to support green product family design. In addition, it provides the redesign methodology such as product family level and component level. A case study used table lamps as an product family's example shows the verification and effectiveness of the proposed method.

• Journal of Digital Convergence
• /
• v.18 no.10
• /
• pp.175-180
• /
• 2020

Through case studies for insurance service marketing using artificial intelligence(AI) in the insurtech industry, it investigated how innovative technologies(artificial intelligence, machine learning etc.) are being used in the insurance ecosystems. In particular, through domestic and international case studies, it was examined by Lemonade's service of insurance contracts and getting the indemnity and AI company's service of calculating the compensation through a medical certificate image based on OCR, which brought disruptive innovations using artificial intelligence. As a result of the case analysis, these services have drastically shortened the lead time of insurance contracts and payment through machine learning using numerous customer data based on artificial intelligence. And accurate and reasonable compensation was calculated in the estimation of indemnity, which has a lot of disputes between customers and insurance companies. It was able to increase customer satisfaction and customer value.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2005.10a
• /
• pp.303-309
• /
• 2005

This paper will suggest how can we guarantee terminal QoS like ship waiting time ratio and ship residing time applying RFID(Radio Frequence Identification) technology, raising up rapidly as a fundamental solution of new growing industry, to port information system. Also, lead time of whole port logistics can be decreased for reduction of loading & discharging time resulted from productivity improvement of Twinlift G/C(Gantry Crane) and Y/T(Yard Tract) etc as applying RFID technology to terminal operation. The purpose of this paper is suggesting of new business model of u-Port that port QoS can be guaranteed from mutual agreement of each terminals RFID technology applied and focusing on the implementation plan.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.38 no.4
• /
• pp.109-116
• /
• 2015

This paper is concerned with the single vendor single buyer integrated production inventory problem. To make this problem more practical, space restriction and lead time proportional to lot size are considered. Since the space for the inventory is limited in most practical inventory system, the space restriction for the inventory of a vendor and a buyer is considered. As product's quantity to be manufactured by the vendor is increased, the lead time for the order is usually increased. Therefore, lead time for the product is proportional to the order quantity by the buyer. Demand is assumed to be stochastic and the continuous review inventory policy is used by the buyer. If the buyer places an order, then the vendor will start to manufacture products and the products will be transferred to the buyer with equal shipments many times. The mathematical formulation with space restriction for the inventory of a vendor and a buyer is suggested in this paper. This problem is constrained nonlinear integer programming problem. Order quantity, reorder points for the buyer, and the number of shipments are required to be determined. A Lagrangian relaxation approach, a popular solution method for constrained problem, is developed to find lower bound of this problem. Since a Lagrangian relaxation approach cannot guarantee the feasible solution, the solution method based on the Lagrangian relaxation approach is proposed to provide with a good feasible solution. Total costs by the proposed method are pretty close to those by the Lagrangian relaxation approach. Sensitivity analysis for space restriction for the vendor and the buyer is done to figure out the relationships between parameters.

• The Journal of Bigdata
• /
• v.7 no.1
• /
• pp.99-111
• /
• 2022

A simulation technique can be used to analyze performance measures and support decision makings in manufacturing systems considering operational uncertainty and complexity. The simulation requires an input modeling procedure to reflect the target system's characteristics. However, data collection to build a simulation is quite limited when a target system includes manual productions with a lot of operational time such as construction equipment assembly lines. This study proposes a procedure for simulation input modeling using video data when it is difficult to collect enough input data to fit a probability distribution. We conducted a video-data analysis and specify input distributions for the simulation. Based on the proposed procedure, simulation experiments were conducted to evaluate key performance measures of the target system. We also expect that the proposed procedure may help simulation-based decision makings when obtaining input data for a simulation modeling is quite challenging.

• Journal of Digital Convergence
• /
• v.12 no.6
• /
• pp.135-144
• /
• 2014

In devising technological innovation strategies and implementing successful technological innovation, some of the most important factors may be to determine whether to protect technological innovation and to choose how to protect it. Traditionally, technological innovation has been emphasized to obtain compensation as much as possible for innovation in terms of economics and strategy. However, it can be regarded as a very complicated problem to determine such a protection and its level. Generally speaking, enterprises have some common mechanisms to secure compensation for technological innovation, which are known to be patents, secrecy and lead time advantage. From the standpoint of enterprises, it is very important what strategies should be devised to secure profits for technological innovation. According to some domestic and oversea research results revealed that specific patents are not the best way to Appropriability for technological innovation, while also implying that there exist several different kinds of mechanisms to Appropriability for technological innovation in each industry. Nevertheless, since it shouldn't be ignored that most of the researches have overlooked the characteristics of Korean enterprises and industrial differences, this study intends to clarify the effectiveness of technological innovation Appropriability mechanisms reflecting actual circumstances and industrial characteristics in Korea while classifying them. Also The questionnaires and delphi method used in this study. As the result of analysis, in the entire industries, the priorities turned out to be in the order of Superior sales and service efforts, Leadtime advantage, Complementary manufacturing.

• 전기의세계
• /
• v.18 no.1
• /
• pp.33-37
• /
• 1969

한전은 1968년 11월 3일 오전 10시 04분을 기하여 154KV 전계통의 직접접지방식 전환을 단행하였다. 종전의 P.C(소고선륜) 중성점접지방식을 직접접지방식으로 전환한것으로서 전력사상 특기 할 만한 근대화사업이며 다년간을 두고 추진해온 중요과제였다. 전력계통의 확대와 복잡화는 선진국가에서도 실시하고 있는 직접접지방식의 채택을 불가변하게 하였고 또한 1차 AID송배전차관도 이의 채택을 조건부로 승인되었던 것으로서 1968년 이후에 건설되는 송변전기기는 직접접지계에서만 운전할 수 있는 절연Level 650KV급이 도입되어 부산화력발전소 3호기가 준공되는 1968년 10월말까지는 직접접지전환이 반드시 이루어져야 하는 실정에 놓여 있었다. 그런데 직접접지방식의 단점인 인접통신선에 미치는 유도장해를 해결하는 문제가 다년간을 두고 진지하게 검토되어 왔으나 해결이 늦어지고 있었다. 사유는 154KV 계통에 인근된 통신선이라면 체신부, 내무부, 교통부, 국방부등 여러기관의 것이 있는데, 유도장해보안방법과 유도보상비문제에 대하여 전력측(상공부, 한전)과 통신측(상기의 체신부등)의 견해차가 해소되지 않기 때문이었다. 그것이 1968년 5월에 와서 전력.통신쌍방이 범국가적입장에서 제반애로를 무릅쓰고 최소한의 투자로 가능한 범위내의 보안책으로서 우선 Arrester 보안방식을 채택하기로 합의되어 경제장관회의를 거쳐 시공하기에 이른것이다. 이 란을 빌려 이 사업의 필요성과 경위및 통신선유도장해방지를 위한 보안방식내용을 간단히 소개함으로써 앞으로 이 분야의 항구적인 유도대책연구에 다소나마 참고가 된다면 다행으로 생각하겠다.면서 예측강우의 질이 저하되기 시작하였으나 QPM을 합성함으로써 생산한 BQPF는 보다 신뢰성있고 양호한 결과를 얻을 수 있었다. 이러한 결과들은 향후 정량적 분포형강우 예측을 이용한 실시간 홍수유출 예측시 댐운영자는 리드타임(홍수선행시간)을 충분히 확보함으로서 안정적이고 예측 가능한 홍수조절을 하는데 도움을 줄 수 있을 것으로 기대된다. 이와 같이 다양한 단기저수지 유입량의 예측정보 제공으로 다목적댐 저수지 운영모형의 효용성을 제고하여 향후 실제 저수지 유입량 예측에 이용함으로써 저수지 단기운영효율 개선에 기여할 수 있을 것으로 사료된다.다. 이것은 여름철 강수량이 증가하고, 호우발생빈도, 특히 8월의 강수일수가 증가하고 있다는 것과 밀접한 관련이 있다. 여름과 가을에 우리나라에 영향을 미치는 태풍의 수는 뚜렷한 추세를 보이지 않으나, 2002년 루사, 2003년 매미로 인하여 각각 6조원, 4조원 이상의 막대한 피해가 발생하였다. 태풍에 의한 피해액은 GDP 대비 약 0.9%(태풍 루사)로 최근 경제상장률과 비교해 보면, 상당한 비율을 차지한다. 우리나라에 영향을 미치는 태풍은 연근해의 해수면 온도가 높아지면 세기가 강해질 가능성이 높다. 폭설과 한파일수도 평년대비 최근 10년 감소하였고 일최저기온이 영하 $10^{\circ}C$ 이하인 날도 연간 발생일수가 감소하였다. 최근 10년간 우리나라 기후의 변화특성은 기온상승과 더불어 서리종료일이 앞당겨지고 열대야가 증가하고 폭설, 한파, 겨울철 일최저기온 영하 10도 이하인 날의 감소 등이 나타나고, 여름철 재해의 원인인 호우일수는 증가하는 추세이다.