• Proceedings of the Korean Operations and Management Science Society Conference
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• 1991.10a
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• pp.464-464
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• 1991

We address the problem of designing a physical CATV network with switched-star topology in which the broadband interactive service is provided. There are two types of decision variables: One is where to place conduit paths, and the other is how many cable units to be installed on each link traversed by an established conduit path. Due to the serious drawback of the conventional approach partitioning the problem into two subproblems, the unified approach handled in one setting is used here to attack the whole problem without dividing into two ones. In this paper, we present a mathematical design model and propose an efficient solution method exploiting the nice structure of it. In addition to this physical design, some results on logical network configuration have also been made. Finally, computaional experiments are conducted to illustrate the efficiency of our design approach.

• Journal of Communications and Networks
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• v.17 no.4
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• pp.384-393
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• 2015

This paper proposes an insect behavior-inspired routing algorithm for large-scale wireless mesh networks. The proposed algorithm is adapted from the behavior of an insect called Bombyx mori, a male silkmoth. Its unique behavior is its flying technique to find the source of pheromones. The algorithm consists of two steps: the shortest-path algorithm and the zigzag-path algorithm. First, the shortest-path algorithm is employed to transmit data. After half of the total hops, the zigzag-path algorithm, which is based on the movement of the male B. mori, is applied. In order to adapt the biological behavior to large-scale wireless mesh networks, we use a mesh topology for implementing the algorithm. Simulation results show that the total energy used and the decision time for routing of the proposed algorithm are improved under certain conditions.

• Proceedings of the IEEK Conference
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• summer
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• pp.159-164
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• 2004

This paper aims towards designing and implementation of a new adaptive Peer to Peer (P2P) network that cluster itself on the basis of semantic proximity. We also developed an algorithm to classify the nodes to form the semantic groups and to direct the queries to appropriate groups without any human intervention. This is done using Bloom filters to summarise keywords of the documents shared by a peer. The queries are directed towards the appropriate clusters instead of flooding them. The proposed topology supports a system for maintaining a global, omnipresent trust value for each peer in an efficient manner both in terms of decision time and network load.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.5
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• pp.283-289
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• 2003

This paper proposes an expert system which can determine automatically the shunting routes corresponding to the given shunting works by considering totally the train operating environments in the station. The expert system proposes the multiple shunting routes with priority of selection based on heuristic search strategy. Accordingly, system operator can select a shunting route with the safety and efficiency among the those shunting routes. The expert system consists of a main inference engine and a sub inference engine. The main inference engine determines the shunting routes with selection priority using the segment routes obtained from the sub inference engine. The heuristic rules are extracted from operating knowledges of the veteran route operator and station topology. It is implemented in C computer language for the purpose of the implementation of the inference engine using the dynamic memory allocation technique. And, the validity of the builted expert system is proved by a test case for the model station.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.2
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• pp.259-266
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• 1992

For CAD/CAPP integration, part information on not only geometry but also machining characteristics should be delivered and commonly used between designers and process planners. In this study, the machining features, as linking factors of the integration, are represented as the combination of functional features and atomic features and grouped into a hierarchical database. And the feature based modelling approach is used by generating information on the machining features in design stage. These features are drawn by analyzing real decision rules of process planners. The database using the machining features is built and used for application modules of process planning, operation planning and standard time estimation.

• Structural Engineering and Mechanics
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• v.7 no.6
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• pp.551-559
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• 1999

This paper presents some simple thinking on an age-old question that given a bridge of a certain span and loading, from the point of view of the structural efficiency, where should the bridge deck be positioned? Generally, this decision is made for other reasons than structural efficiency such as aesthetics and the analyst is often presented with a fait accompli. Using the recently invented Evolutional Structural Optimisation (ESO) method, it is possible to demonstrate that having the deck at different vertical locations can lead to a very different mass and shape for each structural form resembling cable-stayed and cable-truss bridges. By monitoring a performance index which is the function of stresses and volume of discretised finite elements, the best optimised structure can be easily determined and the bridge deck positioning problem can be efficiently solved without resorting to any complex analysis procedures.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.1
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• pp.52-68
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• 2019

Aiming at the optimal placement of communication relay nodes (OPCRN) problem in manned/unmanned aerial vehicle cooperative engagement system, this paper designed a kind of fully connected broadband backbone communication topology. Firstly, problem description of OPCRN was given. Secondly, based on problem analysis, the element attributes and decision variables were defined, and a bi-level programming model including physical layer and logical layer was established. Thirdly, a hierarchical artificial bee colony (HABC) algorithm was adopted to solve the model. Finally, multiple sets of simulation experiments were carried out to prove the effectiveness and superiority of the algorithm.

• Journal of KIISE:Information Networking
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• v.34 no.5
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• pp.328-339
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• 2007

Conventional topology-based routing protocols are not suitable for inter-vehicular communication, where frequent route updates are necessary due to continuous and abrupt changes in network topology Position-based routing protocols are widely accepted to better serve their purpose in such a scenario as they do not require path discovery or maintenance. However they have to deal with the overhead of the location service and inaccurate position information. This paper proposes the MMFP (Multi-hop MAC Forwarding Protocol) for inter-vehicle communication that relies on reachability information collected from received packets in making a forwarding decision without path discovery. The MMFP is designed as an extension to the IEEE 802.11 MAC layer to ensure accuracy in its time-critical operations. This paper also presents some simulation results that demonstrate the superior performance of the MMFP over AODV in a realistic inter-vehicular communication.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1B
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• pp.1-10
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• 2007

We propose a new approach to accommodate bidirectional asymmetric traffic demands as well as unexpected dynamic internet traffic variation in the WDM mesh network by using optical networking technologies. In the proposed scheme, an intermediate node determines the optical path based on the switching statistics of IP router of the node which characterizes the Internet traffic variation, which in effect provides a dynamic and distributed traffic control over the network. It is expected to reduce the efficiency deterioration of RWA(Routing and Wavelength Assignment) due to the real-time variation of Internet traffic so that expandability and flexibility of the network can be enhanced. In this paper, we describe a methodology for traffic behavior analysis at a node, and the decision policy of the establishment/release of optical path. In addition, we evaluate the performance of the proposed scheme through the computer simulations.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.3
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• pp.223-230
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• 2001

Since self-organizing map (SOM) preserves the topology of ordering in input spaces and trains itself by unsupervised algorithm, it is Llsed in many areas. However, SOM has a shortcoming: structure cannot be easily detcrmined without many trials-and-errors. Structure-adaptive self-orgnizing map (SASOM) which can adapt its structure as well as its weights overcome the shortcoming of self-organizing map: SASOM makes use of structure adaptation capability to place the nodes of prototype vectors into the pattern space accurately so as to make the decision boundmies as close to the class boundaries as possible. In this scheme, the initialization of weights of newly adapted nodes is important. This paper proposes a method which optimizes SASOM with genetic algorithm (GA) to determines the weight vector of newly split node. The leanling algorithm is a hybrid of unsupervised learning method and supervised learning method using LVQ algorithm. This proposed method not only shows higher performance than SASOM in terms of recognition rate and variation, but also preserves the topological order of input patterns well. Experiments with 2D pattern space data and handwritten digit database show that the proposed method is promising.