• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.115-118
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• 2004

An abrupt increase of traffic-load in cellular CDMA systems can cause overload and degrade the quality of service (QoS) due to the insufficient radio resources. In this paper, we propose a joint coverage and resource management (JCRM) scheme which can improve the QoS degradation and spectrum utilization. The JCRM scheme hands over overloaded traffic to the neighboring cells by virtually reducing a heavily loaded cell coverage and allocates radio resources based on the necessary handover probability. The proposed scheme can be applied to the existing cellular CDMA systems as well as adaptive coverage management schemes for next generation mobile communication systems.

• Journal of Communications and Networks
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• v.8 no.2
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• pp.182-186
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• 2006

Previous approaches to sizing the carrier spacing for voice-oriented cellular systems have been based on the outage requirement. However, such a design paradigm needs to be changed as the performance of most upcoming cellular systems employing adaptive modulation and coding (AMC) techniques is more sensitive to throughput than outage. In this paper, we propose a novel approach to determining the carrier spacing which is based on a throughput criterion. The proposed method reflects well the characteristics of throughput-sensitive cellular systems that transport multimedia traffic. Numerical results show that our approach requires less carrier spacing, thus leading to more efficient spectrum utilization.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.61
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• pp.137-146
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• 2000

One of the problems faced in implementing cellular manufacturing systems is machine-part group formation. This paper proposes machine-part grouping algorithms based on Self-Organizing Map(SOM) neural networks and K-Means algorithm in cellular manufacturing systems. Although the SOM spreads out input vectors to output vectors in the order of similarity, it does not always find the optimal solution. We rearrange the input vectors using SOM and determine the number of groups. In order to find the number of groups and grouping efficacy, we iterate K-Means algorithm changing k until we cannot obtain better solution. The results of using the proposed approach are compared to the best solutions reported in literature. The computational results show that the proposed approach provides a powerful means of solving the machine-part grouping problem. The proposed algorithm Is applied by simple calculation, so it can be for designer to change production constraints.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.503-510
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• 2003

In CDMA cellular system, because all users share the frequency resource the signals of other user becomes interference which influences the communication quality. The system capacity defined the number of connected users within a cell is determined by the amount of interference, therefore the exact estimation of interference is important to system performance evaluation. In this paper, we propose an approximated function which calculates other cell interference in terms of Riemann-Zeta function in CDMA cellular systems, and compare with simulation results in other to verify its usefulness. The upper and lower bounds of system capacity calculated with the proposed approximated function gives almost alike result with the simulation. The proposed interference bounds are useful to calculate system capacity and to evaluate some algorithm in a hierarchical cellular systems where various propagation environments are mixed.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.158-163
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• 1998

This paper is our first attempt to construct a information processing system such as the living creatures' brain based on artificial life technique. In this paper, we propose a method of constructing neural networks using bio-inspired emergent and evolutionary concept, Ontogeny of living things is realized by cellular automata model and Phylogeny that is living things adaptation ability themselves to given environment, are realized by evolutionary algorithms. Proposing evolving cellular automata neural systems are calledin a word ECANS. A basic component of ECANS is 'cell' which is modeled on chaotic neuron with complex characteristics, In our system, the states of cell are classified into eight by method of connection neighborhood cells. When a problem is given, ECANS adapt itself to the problem by evolutionary method. For fixed cells transition rule, the structure of neural network is adapted by change of initial cell' arrangement. This initial cell is to become a network b developmental process. The effectiveness and the capability of proposed scheme are verified by applying it to pattern classification and robot control problem.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1649-1655
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• 2005

For systems with coexisting cellular and hot-spot cells in broadband orhogonal frequency and code division multiplexing (OFCDM) systems, a suitable cell search algorithm is proposed fur the common pilot channel (CPICH) in the forward link using separated I/Q channel cell specific codes(CSSC), in which the cellular cell specific scrambling code (CCSSC) is assigned to the in-phase (Q) pilot channel of all cellular cells, and the exclusive hot-spot cell specific scrambling code (HSCSSC) group is assigned to the quadrature (Q) pilot channel of all hot-spot cells. Therefore, the proposed algorithm enables a mobile station (MS) to search quickly for the most desirable hot-spot cell due to reducing the effect of CCSSC, when a MS wants to use a mobile internet. The computer simulation results show that the proposed cell search algorithm can achieve faster cell search time performance, compared to conventional cell search methods.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.8
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• pp.481-490
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• 2000

This paper analyzes interference power, Erlang capacity, the number of handoff occurrences, and call blocking probability with respect to the cell radius, the soft handoff region, and the mobile's velocity in a CDMA hierarchical cellular system. The microcell cellular system has the higher Erlang capacity than the macrocell cellular system. However, the microcell cellular system, which has a high system capacity through frequency reuse has the call blocking probability higher than macrocell cellular system. Also the interference power and the call blocking probability are decreased with the operation of soft handoff. Therefore, this paper presents the optimization of soft handoff region so as to maximize system's Erlang capacity with the low the call blocking probability according to mobile's velocity in the CDMA hierarchial cellular system.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.478-484
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• 2021

Cellular resources including transcriptional and translational machineries in bacteria are limited, yet microorganisms depend upon them to maximize cellular fitness. Bacteria have evolved strategies for using resources economically. Regulatory networks for the gene expression system enable the cell to synthesize proteins only when necessary. At the same time, regulatory interactions enable the cell to limit losses when the system cannot make a cellular profit due to fake substrates. Also, the architecture of the gene expression flow can be advantageous for clustering functionally related products, thus resulting in effective interactions among molecules. In addition, cellular systems modulate the investment of proteomes, depending upon nutrient qualities, and fast-growing cells spend more resources on the synthesis of ribosomes, whereas nonribosomal proteins are synthesized in nutrient-limited conditions. A deeper understanding of cellular mechanisms underlying the optimal allocation of cellular resources can be used for biotechnological purposes, such as designing complex genetic circuits and constructing microbial cell factories.

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.4
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• pp.133-149
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• 1997

The major two steps required to design a cellular layout are cell formation and cell layout. Because of the differences between manufacturing and assembly operations, the logic of cell formation and cell layout between an FMS and an FAS is not the same. Since the time for the assembly operations is usualaly relatively short, the transfer time is thus very crucial for the performance of assembly systems. Transfore in a cellular FAS it is more important to eliminate backtracking operations in assembly planning, not to allow intercellular movements in cell formation, and to arrange machines according to assembly sequence in cell layout. This study presents a method for the integrated layout design in cellular FASs considering the characteristics of FAS, layout, and production factors.

• Journal of Information Processing Systems
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• v.6 no.3
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• pp.403-412
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• 2010

Multi-Relay Networks should accommodate mobile users of various speeds. The cellular system should meet the minimum residency time requirements for handover calls while considering an efficient use of available channels. In this paper, we design speed-sensitive handover under dynamic hierarchical cellular systems, in which mobile users are classified according to the mean speed of mobile users and each class has its cellular layer. In order to meet the minimum residency time, the cell size of each cellular layer is dynamically determined depending on the distributions of mean speeds of mobile users. Since the speed-dependent non-preferred cell can provide a secondary resource, overflow and take-back schemes are adopted in the system. We develop analytical models to study the performance of the proposed system, and show that the optimal cell size improves the blocking probability.