• Journal of Korean Institute of Industrial Engineers
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• v.26 no.4
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• pp.296-305
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• 2000

Virtual wavelength path (VWP) is the optical path when a wavelength conversion is possible in a wavelength division multiplexing (WDM) network that is transmission infrastructure for the next generation high speed backbone networks. To achieve efficient design for VWP networks, we must consider VWP routing, wavelength assignment, and wavelength conversion while satisfying many technical constraints of the WDM networks. In this study we propose an integrated model for efficient VWP design in WDM networks. We also develope a 3-phase algorithm, each of which deals with routing, wavelength assignment and route and wavelength reassignment, respectively. In our computational experiments, phase 1 algorithm can solve the problem to the optimality for medium size test networks. Phase 2 algorithm is an efficient heuristic based on a reduced layered network and can give us an effective wavelength assignment. Finally, phase 3 algorithm reconfigure VWP routing and its wavelength assignment to concentrate wavelength conversion nodes in the suggested VWP network.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.3
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• pp.139-146
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• 2016

This study proposes a methodology to analyse social networks among participating design engineers during product development projects. The proposed methodology enables product development managers or the participating design engineers to make a proper decision on product development considering the performance of participating design engineers. It considers a product development environment where an integrated product data management (PDM) system manages the product development data and associated product development processes consistently in its database, and all the design engineers share the product development data in the PDM database for their activities in the product development project. It provides a novel approach to build social networks among design engineers from an operational product development data in the PDM database without surveys or monitoring participating engineers. It automatically generates social networks among the design engineers from the product data and relationships specified by the participants during the design activities. It allows analysts to gather operational data for their analysis without additional efforts for understanding complex and unstructured product development processes. This study also provides a set of measures to evaluate the social networks. It will show the role and efficiency of each design engineers in the social network. To show the feasibility of the approach, it suggests an architecture of social network analysis (SNA) system and implemented it with a research-purpose PDM system and R, a statistical software system. A product configuration management process with synthetical example data is applied to the SNA system and it shows that the approach enables analysts to evaluate current position of design engineers in their social networks.

• Journal of the Korean Geographical Society
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• v.47 no.2
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• pp.226-244
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• 2012

This paper aims to analyze the process of the evolution of Gumi electronics industrial cluster and to understand the role of governments for local industrial dynamics. Gumi was a typical satellite platform type new industrial district up to mid-1990s. At that time, Gumi industrial park was the agglomeration of branch plants headquartered in Capital Region with weak local linkages. During the last two decades, however, Gumi has evolved to an electronics industrial cluster with considerable local interfirm linkages and innovation activities of SMEs. Recognizing government industrial policies is critical in understanding the process of the evolution of Gumi electronics cluster. At the early stage, the state was the developer and locator of business activities within the confines of the Gumi industrial park. In recent years, central government's innovative cluster policy contributed to strengthening networks among firms, universities, and research centers to form local innovation networks as well as networks between large branch plants and SMEs. Gumi city and Gyungsangbuk-do promoted innovative activities of SMEs through the supports of cooperative networks between universities and SMEs. The increasing roles of SMEs and local governments in addition to the large branch plants and the central government have become the basis of the evolution of industrial cluster in Gumi.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.640-643
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• 2004

As the size of a network increases, the network complexity and maintenance cost is high. In literatures, many cost factors of multistage interconnection networks were intensively investigated. However, in some parts, these types of cost definition are not satisfactory enough since they don't relate the cost measure to technology closely and also fail to incorporate exact tradeoffs in designing the network. In this paper, we propose some cost effective measures which combine the cost factors with performance-related reliability measures, and compare several networks for a guidance to select a certain case depending on the principal concerns for use.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.77-79
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• 2000

Industrial communication networks have attracted much attention in the area of decentralized control systems for factory automation and computer integrated manufacturing. In this paper, we investigate the rate-based traffic control of industrial communication networks employing LonWorks to improve the performance measures of throughput, fairness, and error rates. To this end, we utilize the Feedback channel information through the additional network monitoring node and make the overall system closed-loop. We demonstrate the improved performance of the controlled network system by the experimentation upon an implemented lab-scale network system.

• Journal of Communications and Networks
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• v.11 no.3
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• pp.211-228
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• 2009

After clarifying the underlying problems in a secure network storage, we introduce two important requirements, leakageresilience and availability in higher levels respectively, for data keys that are used to protect remotely-stored data. As a main contribution of this paper, we give a new security layer for overlay networks by proposing a leakage-resilient authentication and data management system. In this system, we specifically propose a single mode and a cluster mode where the latter provides a higher level of both leakage-resilience and availability for the data key.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.1
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• pp.153-163
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• 2007

An adaptive framework paradigm where the bandwidth values of the ongoing calls vary according to the trafficsituations is one of the promising concepts for overcoming poor resource conditions due to handoffs in mobilecellular networks. However, quantifying the level of bandwidth degradation of the ongoing calls in an adaptiveframework is important in view of Quality of Service (QoS) Provisioning. Therefore we introduce new QoSparameters, the Degradation Degree Ratio (DDR), which represents the average portion of the degradationdegree during degradation pehod of a call, and the Degradation Area Ratio (DAR), which represents the averageratio of a call's degradation level considering both the period and the degree of degradation jointly in multi-levelbandwidth service. We also develop a new analytical model for estimating the QoS measures such as theDegradation Pehod Ratio (DPR), DDR and DAR. We show how to calculate the QoS measures and illustrate themethod by numerical examples. The proposed model can be used to determine the optimal parameter of theCAC scheme and analyze the sensitivity ofthe QoS parameters in adaptive networks.

• Journal of Industrial Technology
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• v.26 no.A
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• pp.147-152
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• 2006

Wireless Sensor Networks provide a new paradigm for sensing and disseminating information from various environments, with the potential to serve many and diverse applications. Recent advancement in wireless communications and electronics has enabled the development of low-cost sensor networks. The sensor networks can be used for various application areas. For different application areas, there are different technical issues that researchers are currently resolving. The current state of the art of sensor networks is captured in this article, where solutions are discussed under their related protocol stack layer sections. This article also points out the open research issues and intends to spark new interests and developments in this field. In order to evaluate the application of field monitoring system, lab tests, field test and FEM analysis are conducted. Therefore the accuracy of RFID wireless sensor data is verified.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3955-3966
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• 2014

With the exponentially increasing Internet traffic and emergence of more versatile and heterogeneous applications, the design of datacenter networks (DCNs) is subject to unprecedented requirements for larger capacity and more flexible switching granularities. Envisioning Optical-Orthogonal Frequency Division Multiplexing (O-OFDM) as a promising candidate for such a scenario, we motivate the use of O-OFDM as the underlying switching technology in order to provide sufficient switching capacity and elastic bandwidth allocation. For this purpose, this article reviews the recent progresses of DCN deployment and assesses the scenario where the O-OFDM transmission and switching technology is employed in the underlying transport plane. We discuss the key issues of the datacenter-oriented O-OFDM optical networks, and in particular, elaborate on a number of open issues and solutions including system interconnection architecture, routing and resource assignment, survivability, and energy-efficiency.

• Journal of Korea Society of Industrial Information Systems
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• v.6 no.2
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• pp.1-6
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• 2001

This paper proposes a pattern classification method of interval vectors by interval neural networks. The proposed method can be applied to pattern classification where attribute values of each sample are given as interval numbers. First, an architecture of interval neural networks is proposed for dealing with interval input vectors. Next, a learning algorithm is derived from the cost function. a cost function is defined using the interval output from the interval neural network and the corresponding target output. Last, using numerical examples, the proposed approach is illustrated and compared with other approach based on the standard back-propagation neural networks.