• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 1999년도 춘계공동학술대회:정보화시대의 지식경영
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• pp.426-426
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• 1999

;There are many sources of uncertainty in a typical production and inventory system. There is uncertainty as to how many items customers will demand during the next day, week, month, or year. There is uncertainty about delivery times of the product. Uncertainty exacts a toll from management in a variety of ways. A spurt in a demand or a delay in production may lead to stockouts, with the potential for lost revenue and customer dissatisfaction. Firms typically hold inventory to provide protection against uncertainty. A cushion of inventory on hand allows management to face unexpected demands or delays in delivery with a reduced chance of incurring a stockout. The proposed strategies are used for the design of a probabilistic inventory system. In the traditional approach to the design of an inventory system, the goal is to find the best setting of various inventory control policy parameters such as the re-order level, review period, order quantity, etc. which would minimize the total inventory cost. The goals of the analysis need to be defined, so that robustness becomes an important design criterion. Moreover, one has to conceptualize and identify appropriate noise variables. There are two main goals for the inventory policy design. One is to minimize the average inventory cost and the stockouts. The other is to the variability for the average inventory cost and the stockouts The total average inventory cost is the sum of three components: the ordering cost, the holding cost, and the shortage costs. The shortage costs include the cost of the lost sales, cost of loss of goodwill, cost of customer dissatisfaction, etc. The noise factors for this design problem are identified to be: the mean demand rate and the mean lead time. Both the demand and the lead time are assumed to be normal random variables. Thus robustness for this inventory system is interpreted as insensitivity of the average inventory cost and the stockout to uncontrollable fluctuations in the mean demand rate and mean lead time. To make this inventory system for robustness, the concept of utility theory will be used. Utility theory is an analytical method for making a decision concerning an action to take, given a set of multiple criteria upon which the decision is to be based. Utility theory is appropriate for design having different scale such as demand rate and lead time since utility theory represents different scale across decision making attributes with zero to one ranks, higher preference modeled with a higher rank. Using utility theory, three design strategies, such as distance strategy, response strategy, and priority-based strategy. for the robust inventory system will be developed.loped.

• 전자공학회논문지C
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• 제36C권11호
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• pp.64-74
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• 1999

본 논문에서는 연결 에지 추가 기법을 이용하여 주어진 클락 스큐를 만족시키면서 동시에 총 배선 길이를 증가시키지 않는 새로운 클락 배선 최적화 알고리즘을 제안한다. 고속의 동기식 집적 회로에서는 클락 스큐가 회로의 속도를 제한하는 주된 요소로 작용하므로 성능의 향상을 위해서는 클락 스큐를 최소화해야 한다. 일반적으로 클락 스큐를 최소화하면 총 배선 길이가 증가하므로 오동작하지 않는 클락 스큐 범위 내에서 클락 배선을 수행한다. 이를 이용하여 본 논문에서는 제로 스큐 트리에 연결 점 이동 방법을 적용하여 총 배선길이와 지연 시간을 감소시킨다. 제안하는 알고리즘은 클락 트리의 두 노드 사이에 연결 에지를 추가하여 일반적인 그래프 형태의 클락 토폴로지를 구성하여 주어진 클락 스큐 범위를 만족시키고 동시에 총 배선장의 증가를 억제한다. 연결 에지를 구성하는 두 노드를 선택하기 위한 새로운 비용 함수를 고안하였다. 클락 트리 상에서 지연 시간의 차이가 크면서 거리가 가까운 두 노드를 연결함으로서 싱크 사이의 지연 시간의 차를 감소시켜서 클락 스큐를 감소시킨다. 또한 클락 신호선의 지연 시간 최소화를 위하여 배선 토폴로지 설계 및 배선 폭 조절 알고리즘을 개발하였다. 본 논문에서 제안하는 알고리듬을 C 프로그램 언어로 구현하여 실험한 결과 주어진 스큐 범위를 만족시키면서 지연 시간을 감소시키는 효과를 얻을 수 있었다

• 한국건설관리학회논문집
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• 제11권6호
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• pp.54-64
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• 2010

기업은 이익창출을 위해 자본과 비용을 투입하고 재무적 타당성을 분석하여 투자의 가부를 결정한다. 일반적으로 실물자산의 투자가 창출하는 현금흐름은 투자분석시의 결과와는 달리 불확실하게 변화하고 실물자산이 내포한 여러 경영상의 유연성이 유발하는 비대칭수익구조도 사업의 가치에 영향을 미친다. 실물자산의 투자가 수반하는 다양한 경영상의 유연성들 중, 경영진이 특정 기간 동안 투자를 지연할 수 있는 투자지연의 의사결정은 시장에서 새로운 정보가 유입되면 합리적인 대응을 가능케하여 사업의 가치를 증가시키는 것으로 알려져 왔으나 투자시기의 결정에 관한 연구는 부족해왔다. 그러므로 본 연구는 투자지연이 유효한 실물자산의 투자에서 합리적인 투자시기의 결정을 위해 투자지연에 의한 사업가치의 증분과 손실회복비용을 옵션 가격결정 및 관련 금융 경제이론에 기반하여 추정하고 이를 수학적 변분원리를 이용하여 최적의 투자시기 탐색을 위한 이론 모델을 구성 한 후 부동산 실물자산인 REITs(Real Estate Investment Trusts)의 사례에 적용 및 분석함으로써 실물자산의 투자시기 결정을 위한 이론적인 틀을 제시하고자 한다.

• 한국콘텐츠학회논문지
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• 제2권4호
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• pp.51-58
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• 2002

전자상거래 사용자의 폭발적인 증가는 전자상거래 시스템의 급격한 로드 증가와 네트워크 트래픽을 증가시키고 있다. 또한 전자상거래 시스템에서 동영상을 포함한 자료가 점차 늘어나고 있고 이에 따라 인터넷 서비스 제공업자들은 시스템의 관리와 회선의 유지를 위해 막대한 비용을 지불하고 있다. 이러한 시스템의 로드와 네트워크의 트래픽 증가는 웹 고객의 서비스 요청에 대한 응답 속도의 지연을 가져오게 되며 이는 고객만족도를 감소시켜 e-비지니스 기업의 경쟁력을 떨어뜨리는 중대한 요인으로 작용하고 있다. 본 연구에서는 마이크로소프트사의 최신 버전인 닷넷을 기반으로 한 전자상거래 시스템에서, 응답 지연 속도를 개선한 전자상거래 시스템을 설계하고 실험을 통해 성능을 분석하였다. 실험 결과 제안한 시스템은 웹 고객의 다양한 요구에 대해 개선된 응답 속도와 빠른 적응성을 가질 수 있으며, 특히 전자상거래 시스템에 대해 동시에 발생하는 다수의 다중 사용자의 요구로 인해 발생되는 응답 속도의 지연을 막을 수 있을 것으로 기대된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권5호
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• pp.1708-1734
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• 2022

In the development of logistics system, the breakthrough of important technologies such as technology platform for logistics information management and control is the key content of the study. Based on Javascript and JQuery, the logistics system realizes real-time monitoring, collection of historical status data, statistical analysis and display, intelligent recommendation and other functions. In order to strengthen the cooperation of warehouse storage, enhance the utilization rate of resources, and achieve the purpose of real-time and visual supervision of transportation equipment and cargo tracking, this paper studies the VNF dynamic deployment and SFC routing problem in the network load change scenario based on the logistics system. The BIP model is used to model the VNF dynamic deployment and routing problem. The optimization objective is to minimize the total cost overhead generated by each SFCR. Furthermore, the application of the SFC mapping algorithm in the routing topology solving problem is proposed. Based on the concept of relative cost and the idea of topology transformation, the SFC-map algorithm can efficiently complete the dynamic deployment of VNF and the routing calculation of SFC by using multi-layer graph. In the simulation platform based on the logistics system, the proposed algorithm is compared with VNF-DRA algorithm and Provision Traffic algorithm in the network receiving rate, throughput, path end-to-end delay, deployment number, running time and utilization rate. According to the test results, it is verified that the test results of the optimization algorithm in this paper are obviously improved compared with the comparison method, and it has higher practical application and promotion value.

• 대한전자공학회논문지TC
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• 제47권1호
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• pp.69-76
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• 2010

FTTH(Fiber To The Home)가입자 망에 있어 패킷단위의 정보처리를 위한 3 비트, 4 비트의 전광학 헤더인식 과정을 설명하고 실험을 성공적으로 수행하였다. 패킷의 목적지를 나타내는 3, 4 비트 헤더정보에 따른 하나의 신호가 각각 8개, 16개의 타임슬롯 상의 지정된 한 곳에 나열되었다. RN(remote node)에서의 self-routing을 위해 제안된 헤더인식 기술은 TDM 방식의 원리를 응용하여 스위치와 지연라인만을 사용함으로써 매우 간단한 회로를 구성하여 높은 신뢰도와 낮은 비용으로 가입자 망을 구축할 수 있다. 또 RN으로부터 각 가입자의 독립 전송선로를 확립함으로써 TDM-PON 방식의 최대 취약점이었던 광 신호의 감쇄와 보안성의 문제를 해결할 수 있다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1685-1688
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• 2002

Application Routing Load Balancing (ARLB) is a novel load balancing mode that combines QoS routing and load balancing in per application to support QoS far real-time application based on wired network. Zone Routing Protocol (ZRP) is a recent hybrid proactive/reactive routing approach in an attempt to achieve scalability of ad-hoc network. This routing approach has the potential to be efficient in the generation of control traffic than traditional routing schemes. Up to now, without proper load balancing tools, the ZRP can actually guarantee QoS for delay-sensitive applications when congestion occurred in ad-hoc network. In this paper, we propose the ARLB to improve QoS fur delay-sensitive applications based on ZRP in ad-hoc network when congestion occurred and to be forwarding mechanism fur route coupling to support QoS for real-time applications. The critical point is that the routing metric of ARLB is originally designed for wired network environment. Therefore, we study and present an appropriate metric or cost computation routing of ARLB for recently proposed ZRP over ad-hoc network environment.

• Industrial Engineering and Management Systems
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• 제14권4호
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• pp.372-378
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• 2015

In labor-intensive enterprise, such as garment factory, assembly line is widely used as a manufacturing process for reducing costs and production time. However, for the sake of the various working capacity of worker, idle or delay may happen and influence the rear processes. If these unforeseeable delay happened continuously, it may influence the whole manufacturing process and a model, which is called limited-cycle model with multiple periods (LCMwMP), is assumed to evaluate the influence risk. In order to minimize the risk, the assignment of the workers is focused on. In this paper, we deal with an assembly line as LCMwMP model when two kinds of workers exist, whose efficiency is assumed to two different groups. We consider an optimization problem for finding an assignment of workers to the line that minimizes total expected risk, which is exchanged to expected cost by reset model of LCMwMP. First, reset model as a simple model of LCMwMP is introduced. Then, some hypotheses of the rules of the optimal worker assignment are proposed and some numerical experiments are researched assuming the processing time as Erlang distribution. Finally, the other rules on other certain conditions are discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권8호
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• pp.2764-2782
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• 2021

Existing city-level boundary nodes identification methods need to locate all IP addresses on the path to differentiate which IP is the boundary node. However, these methods are susceptible to time-delay, the accuracy of location information and other factors, and the resource consumption of locating all IPes is tremendous. To improve the recognition rate and reduce the locating cost, this paper proposes an algorithm for city-level boundary node identification based on bidirectional approaching. Different from the existing methods based on time-delay information and location results, the proposed algorithm uses topological analysis to construct a set of candidate boundary nodes and then identifies the boundary nodes. The proposed algorithm can identify the boundary of the target city network without high-precision location information and dramatically reduces resource consumption compared with the traditional algorithm. Meanwhile, it can label some errors in the existing IP address database. Based on 45,182,326 measurement results from Zhengzhou, Chengdu and Hangzhou in China and New York, Los Angeles and Dallas in the United States, the experimental results show that: The algorithm can accurately identify the city boundary nodes using only 20.33% location resources, and more than 80.29% of the boundary nodes can be mined with a precision of more than 70.73%.

• 전자공학회논문지S
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• 제34S권10호
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• pp.33-51
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• 1997

On ATM-based wired/wireless integrated network, we apply the connection re-routing method[1] which reduced the inter-cluster handoff delay by reserving VPI/VCLs for possible inter-cluster handoff calls in advance. Additionally, we propose wired resource reservation methods, which are ausiliary method and split method, for handoff QoS guarantee of various expected services. The characteristics of these methods reserve wired connection resources based on the information on the possible inter-cluster handoff calls. With mathematical analysis, we also propose each algorithm and cost function for deciding an optimal amount in reserving resources. With numberical examples, we can see that the auxiliary method effectively reduces the cost in all cases(.alpha.>.betha., .alpha.=.betha., and .alpha.<.betha.). The split method has a little cost-reduction effects, when handoffs call does not have priority over new calls (that is, .alpha..leq..betha.) and the total capacity is relatively large. In other cases, the split method, however, has effective cost-reduction effects. The numerical resutls show that these reservation methods ca flexibly cope with the time-variant environment and meet the QoS requriements on the inter-cluster handoff calls.