• Journal of Korean Institute of Industrial Engineers
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• v.20 no.4
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• pp.135-149
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• 1994

Demand forecasting is to estimate the demand of customers for products and services. Since the future is uncertain in nature, it is too difficult for us to predict exactly what will happen. Therefore, when the forecasting is performed upon the uncertain future, it is realistic to estimate the value of demand as an interval or a fuzzy number instead of a crisp number. In this paper, we propose a demand forecasting method using the standard back-propagation algorithm and then we extend the method to the case of interval inputs. Next, we demonstrate that the proposed method using the interval neural networks can represent the fuzziness of forecasting values as intervals. Last, we propose a demand forecasting method using the transformed input variables that can be obtained by taking account of the degree of influence between an input and an output.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.3
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• pp.219-225
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• 2006

We consider a routing and wavelength assignment (RWA) for the efficient operation of WDM networks. For a given physical network, a set of selected pairs of nodes, the number of required connections for each selected pair of nodes, and a set of available wavelengths, the RWA is to realize as many connections as possible without wavelength collision. We give an integer programming formulation and an algorithm based on column generation. Though the proposed algorithm does not guarantee optimal solutions, test results show that the algorithm gives probably good solutions.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.4
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• pp.571-578
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• 1998

In this paper, we deal with a node weighted Steiner Ring Problem (SRP) arising from the deployment of Synchronous Optical Networks (SONET), a standard of transmission using optical fiber technology. The problem is to find a minimum weight cycle (ring) covering a subset of nodes in the network considering node and link weights. We have developed two mathematical models, one of which is stronger than the other in terms of LP bounds, whereas the number of constraints of the weaker one is polynomially bounded. In order to solve the problem optimally, we have developed some preprocessing rules and valid inequalities. We have also prescribed an effective heuristic procedure for providing tight upper bounds. Computational results show that the stronger model is better in terms of computation time, and valid inequalities and preprocessing rules are effective for solving the problem optimally.

• IE interfaces
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• v.14 no.2
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• pp.148-157
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• 2001

This paper considers a network restoration algorithm for all-optical WDM networks. As the increasing traffic and transmission speed, any failure on the networks will lead to loss of huge data and disruption of the services. Therefore, a network restoration algorithm is necessary for the high-speed all-optical networks. This paper suggests a distributed restoration algorithm for line or channel level failures under the dynamic rerouting. For the algorithm, some measures for performance evaluation are explicitly derived and simulation studies are exploited to evaluate its usability by SLAM(Simulation Language for Alternative Modeling) II.

• World Technopolis Review
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• v.1 no.1
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• pp.56-64
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• 2012

This paper provides a case study to explore the Kitakyushu case as a good referential example on STP development for rejuvenation of declining industrial city. The major data for the case, basically, has been sourced from some materials published by the municipality of Kitakyushu City, the website of the Kitakyushu Science and Research Park (KSRP) etc. The City of Kitakyushu has promoted the KSRP development to overcome industrial decline and stimulate city renaissance as a new industrial city. The core of the development was to develop a high-level education and research environment by gathering several HEIs into one campus. Based on the environment, the Kitakyushu Foundation for the Advancement of Industry and Science and Technology (FAIS) played the critical role as a coupler to make various networks and boost industry-academiaadministration innovation. The KSRP, and then, has been designated as a project area of some cluster projects initiated by the central government. It means that local projects can be synchronized, synergized and synthesized with national projects in the KSRP. In addition, through a series of the environmental approach from the Kitakyushu Eco-town Project to the Low Carbon Society Project, the development of the KSRP is being extended into the region. In the Kitakyushu case, networking is the essence of the KSRP development from the planning stage. First of all, the plan put emphasis on networking of academia for the knowledge creation based on competitive collaboration that is expected as the mainspring of rejuvenating declining industrial area and making a new industrial city that the plan aimed. Then, the roles of two organizations are very important for networking, especially networking of networks: the Campus Management Committee as an interface and the FAIS as a coupler. STP development without some strategic considerations for networking as the way of interaction among its participants cannot be a tool to promote innovation and rejuvenate a declining industrial area. The Kitakyushu case mentioned above explains the matter clearly.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.271-275
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• 2005

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.

• Journal of Korean Institute of Industrial Engineers
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• v.34 no.2
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• pp.181-189
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• 2008

Survivability of a network is one of the most important issues in designing present-day communication networks. For the past few decades, a lot of researches have proposed the mathematical models to evaluate the survivability of networks. In this paper, we attempt to survey such researches and classify them based on how these researches measure the survivability of a network.

• Journal of Industrial Technology
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• v.12
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• pp.37-49
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• 1992

We proposed an integrated simulator scheme for communication networks. The network modeling and Analysis methologies are firstly discussed along the design procedure of a network simulator, and then, the structure, kernel, and user interfaces are defined for the simulator. Finally, for the verification of our approach, simulations are performed for a simple queueing network and a pure ALOHA system using Ptolemy, a multi-paradigm simulation enviroment.

• Knowledge Management Research
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• v.2 no.1
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• pp.133-144
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• 2001

Clusters mean geographic concentrations of interconnected companies and institutions in a particular field. Geographic, cultural, and institutional proximity provides companies with special access, closer relationships, better information, powerful incentives, and other advantages that are difficult to tap from a distance. And clusters are the knowledge-sharing networks which are composed of co-existence of related industries and supporting industries, sophisticated demand, sponsor of various exhibitions and events, liaison of peripheries and clusters, liaison of clusters and clusters, and governments' willingness for promoting clusters' development.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1996.10a
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• pp.211-216
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• 1996

This paper propose a fuzzy regression method using fuzzy neural networks when a membership value is attached to each input-output pair. First, an architecture of fuzzy nerual networks with fuzzy weights and fuzzy biases is shown. Next a cost function is defined using the fuzzy output from the fuzzy neural network and the corresponding target output with a membership value.A learning algorithm is derived from the cost function. The derived learning algorithm trains the fuzzy neural network so that the level set of the fuzzy output includes the target output. Last, the proposed method is applied to the quality evaluation problem of injection molding.