• 한국산업정보학회논문지
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• 제11권1호
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• pp.1-6
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• 2006

Queueing models are good models for fragments of communication systems and networks, so their investigation is interesting for theory and applications. Theses queues may play an important role for the validation of different decomposition algorithms designed for investigating more general queueing networks. So, in this paper we illustrate that the batch size distribution affects the loss probability, which is the main performance measure of a finite buffer queues.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2007년도 춘계학술대회
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• pp.26-31
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• 2007

An ad hoc network is a collection of mobile nodes without any Infrastructure. However, ad hoc networks are vulnerable to attacks such as routing disruption and resource consumption; thus, routing protocol security is needed This paper proposes a secure and efficient routing protocol for mobile ad hoc networks, where only one-way hash function are used to authenticate nodes in the ROUTE REQUEST, while additional public-key cryptography is used to guard against active attackers disguising a node in the ROUTE REPLY.

• 산업경영시스템학회지
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• 제18권36호
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• pp.153-158
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• 1995

Finding shortest paths in networks is the fundamental problem in network theory and has numerous in Operations Research and related fields. The purpose of this study is to present a algorithm for solving the length of the shortest paths from a fixed node in a general network in which the arc distance can be arbitrary value. This algorithm has a worst computational bound of $n^3/4$ additions and $n^3/4$ comparisons, which is lower the worst computational bounds of other available algorithms.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권8호
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• pp.3224-3242
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• 2020

Internet of Things (IoT) networks composed of a large number of sensors and actuators generate a huge volume of data and control commands, which should be enforced by strong data reliability. The end-to-end data reliability of IoT networks is an essential industrial enabler. Blockchain technology can provide strong data reliability and integrity within IoT networks. We designed a lightweight end-to-end blockchain network that applies to common IoT applications. Its enhanced modular architecture and lightweight consensus mechanism guarantee its practical applicability for general IoT applications. In addition, the proposed blockchain network is highly software compatible because it adopts the Hyperledger development environment. Directly embedding the proposed blockchain middleware platform in small computing devices proves its practicability.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1993년도 추계학술대회발표논문집; 서강대학교, 서울; 25 Sep. 1993
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• pp.133-133
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• 1993

• 산업공학
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• 제18권3호
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• pp.277-287
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• 2005

In this paper, we deal with a new techno-economic modeling and analysis for optical access networks. In deploying the fiber-to-the-home (FTTH) architecture, network planner needs to consider the following techno-economic issues: when do we need to upgrade existing local access network to FTTH network? how much do we invest to maximize profit? In order to answer these techno-economic questions, we need to consider the impact of emerging technologies and business environment. Toward this end, we develop a new techno-economic modeling to deal with the inherent complexity of technology evolution and cost economics. In particular, the new modeling approach provides us with an techno-economic analysis of technology alternatives such as ethernet passive optical network (E-PON) and wavelength division multiplex passive optical network (WDM-PON). In this analysis, we focus on the impact of critical factors such as the cost characteristic of proposed architecture and digital subscriber line (DSL) subscriber's churn-in to FTTH service and churn-out. We develop mixed integer-programming models for finding the evolution path of local access networks to broadband network architectures.

• 대한지리학회지
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• 제29권2호
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• pp.117-136
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• 1994

오늘날 첨단산업의 발전과 더불어 산업의 공간구조 변화가 지역적인 차원은 물론 국제적인 차원에서 일어나고 있으며 신산업지구의 등장은 그 좋은 예라고 볼 수 있다. 신산 업지구는 소기업 중심의 유연적 전문화에 의해서만 형성되는 것이 아니라 생산체계, 생산의 네트워크, 뿌리내림(embeddedness), 기업의 규모 등 4가지 요인과 관련하여 다양한 형태로 형성발전하는 역동성을 가지고 있다. 신산업지구는 기본적으로 네트워크의 유형에 따라 4개 의 기본유형과 5개의 혼합형으로 구분될 수 있는데, 이들은 위의 4가지 요인 외에도 기업간 권한의 계층성, 협력과 경쟁, 제도적 요인, 매몰비용(sunk costs) 등에 의해서 그 특성이 구 분되며 사례를 확인할 수 있다. 9개의 유형은 모두 첨단산업과 관련지을 수 있으나, 첨단산 업의 발전과 더불어 혼합형 산업지구가 형성발전될 가능성이 더 크다. 과거의 산업지구는 역사적 우연성에 의해서 형성되는 경우가 흔하였지만 오늘날 첨단산업과 관련한 산업지구는 정책과 전략이 그 형성과 발전에 중요하다. 따라서 제도적 지원체계의 마련, 매몰비용의 절 감, 국제화에 대한 대응 등의 여러 가지 전략이 추진되어야 신산업지구의 형성과 역동적인 발전이 가능하다.

• 산업기술연구
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• 제21권B호
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• pp.91-98
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• 2001

In this paper, center detection and motion analysis of a moving object are studied. Kohonen's self-organizing neural network models are used for the moving objects tracking and time delay neural networks are used for dynamic characteristic analysis. Instead of objects brightness, neuron projections by Kohonen Networks are used. The motion of target objects can be analyzed by using the differential neuron image between the two projections. The differential neuron image which is made by two consecutive neuron projections is used for center detection and moving objects tracking. The two differential neuron images which are made by three consecutive neuron projections are used for the moving trajectory estimation. It is possible to distinguish 8 directions of a moving trajectory with two frames and 16 directions with three frames.

• Management Science and Financial Engineering
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• 제10권1호
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• pp.53-75
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• 2004

Most existing studies on time-dependent networks have been focused on finding a minimum delay path given a departure time at the origin. There, however, frequently happens a situation where users can select any departure time in a certain time interval and want to spend as little time as possible on traveling the networks. In that case. the delay spent on traveling networks depends on not only paths but also the actual departure time at the origin. In this paper, we propose a new problem in time-dependent networks whose objective is to find an optimal departure time given possible departure time interval at the origin. From the optimal departure time, we can obtain a path with minimum delay among all paths for possible departure times at the origin. In addition, we present an algorithm for finding an optimal departure time by enumerating trees which remain shortest path tree for a certain time interval.

• 대한산업공학회지
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• 제17권2호
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• pp.87-95
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• 1991

The exact solution of the closed queueing networks(CQN) is known only for the product form (BCMP) queueing networks. Various computational algorithms are available to derive system throughput(the rate at which a system completes units of computational work) of the networks. However, the computational expense of an exact solution is often excessive when there are multiple classes of cutomers. Instead of computing the exact values, it may be sufficient to derive bounds on the performance measures. Techniques for obtaining bounds on BCMP queueing networks have appeared in the past years. This paper also presents bounds on throughput in CQN models with multiple classes of customers.