• Journal of applied mathematics & informatics
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• v.31 no.3_4
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• pp.577-594
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• 2013

In this paper, we study the global stability and the existence of almost periodic solution of high-order Hopfield neural networks with distributed delays of neutral type. Some sufficient conditions are obtained for the existence, uniqueness and global exponential stability of almost periodic solution by employing fixed point theorem and differential inequality techniques. An example is given to show the effectiveness of the proposed method and results.

• Journal of the Economic Geographical Society of Korea
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• v.13 no.2
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• pp.159-180
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• 2010

Research on regional innovation has recently emphasized the significance and necessities of global networks. However, theoretical arguments have not provided the answers for how global networks are actually formed and work, and the related discussions have not been cohesive while introducing separate concepts originated from diverse disciplines without connecting them with each other. This paper intends to critically review theoretical concepts on spatialities of regional innovation networks and demonstrate limits of each concept, arguing that a synthetic perspective is necessary for understanding how global innovation networks work. The author introduces, specifically, the concept of transnational ethnic communities, which has been recently given much attention to investigate global innovation networks, and provide its theoretical and policy implications.

• Journal of Internet Computing and Services
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• v.10 no.5
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• pp.1-12
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• 2009

A routing policy based on BGP community routing permits to select a specific route for particular network by making use of user-defined routing policies. Especially, community based routing policy is recently getting a great concern to enhance overall performance in the global research networks which are generally inter-connected large number of different characterized networks. In this paper, we analyze the community routing which has been applied in existing global research networks in the network performance point of view, and catch hold of problems caused by the routing performance in a new global research network. Then, we suggest an effective community routing policy model along with an interconnection architecture of research networks, in order to make correct some wrong routings and resolve an asymmetric routing problem, for a new global research network. Our work is expected to be utilized as an enabling base technology to improve the network performance of future global research networks as well as commercial networks.

• Journal of the Korean Mathematical Society
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• v.48 no.2
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• pp.223-240
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• 2011

In this paper, the problem on periodic solutions of the bidirectional associative memory neural networks with both periodic coefficients and periodic time-varying delays is discussed. By using degree theory, inequality technique and Lyapunov functional, we establish the existence, uniqueness, and global asymptotic stability of a periodic solution. The obtained results of stability are less restrictive than previously known criteria, and the hypotheses for the boundedness and monotonicity on the activation functions are removed.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1074-1077
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• 2002

This paper proposes an adaptive pricing system with scheduling to balance the demand for contents and to realize an effective use of resources in contents delivery networks. In the proposed adaptive pricing system, the table of the service levels and prices (tariff) is shown to each user at the start of service and each user chooses one of the service classes. These prices are decided adaptively reflecting the congestion state of the networks. Then, by the proposed scheduling algorithm, these requests are scheduled so as to keep the service level agreements completely.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.84-86
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• 2010

Time information and time synchronization are fundamental building blocks in wireless sensor networks since many sensor network applications need time information for object tracking, consistent state updates, duplicate detection and temporal order delivery. Various time synchronization protocols have been proposed for sensor networks because of the characteristics of sensor networks which have limited computing power and resources. However, none of these protocols have been designed with time representation scheme in mind. Global time format such as UTC TOD (Universal Time Coordinated, Time Of Day) is very useful in sensor network applications. In this paper we propose time keeping and synchronization method for global time presentation in wireless sensor networks.

• Journal of the Economic Geographical Society of Korea
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• v.26 no.4
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• pp.408-420
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• 2023

As the cultural industry might be regarded as the most intimate industry to the general public, it is relatively easy to be widely accepted. With the development of the internet, not only people in various countries have been closely connected, but production networks around the world might also be connected with each other. This article will use data and case studies to clarify how global production networks operate in the development of the cultural industry. By taking the relatively novel point of contact of connection between global production networks and the development of the cultural industry, it summarizes the development models of the film, television and music sectors in the Korean cultural industries. The study found that the development model of the film, television and music industry from the 1990s to the present could be divided into four phases, and most firms are now in the outsourcing and expansion phase. Relying on the huge production networks, these two industries are likely to be improving their popularity and added value through global cooperation.

• Journal of applied mathematics & informatics
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• v.29 no.1_2
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• pp.211-225
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• 2011

In this paper, a class of bi-directional associative memory (BAM) fuzzy cellular neural networks with distributed delays and impulses is formulated and investigated. By employing an integro-differential inequality with impulsive initial conditions and the topological degree theory, some sufficient conditions ensuring the existence and global exponential stability of equilibrium point for impulsive BAM fuzzy cellular neural networks with distributed delays are obtained. In particular, the estimate of the exponential convergence rate is also provided, which depends on the delay kernel functions and system parameters. It is believed that these results are significant and useful for the design and applications of BAM fuzzy cellular neural networks. An example is given to show the effectiveness of the results obtained here.

• Journal of the Korean Mathematical Society
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• v.48 no.4
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• pp.727-747
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• 2011

By employing coincidence degree theory and using Halanay-type inequality technique, a sufficient condition is given to guarantee the existence and global exponential stability of periodic solutions for the two-dimensional discrete-time Cohen-Grossberg BAM neural networks. Compared with the results in existing papers, in our result on the existence of periodic solution, the boundedness conditions on the activation are replaced with global Lipschitz conditions. In our result on the existence and global exponential stability of periodic solution, the assumptions in existing papers that the value of activation functions at zero is zero are removed.

• Journal of applied mathematics & informatics
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• v.28 no.3_4
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• pp.583-596
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• 2010

In this paper, the problem of delay-dependent stability analysis for cellular neural networks systems with time-varying delays was considered. By using a new Lyapunov-Krasovskii function, delay-dependant stability conditions of the delayed cellular neural networks systems are proposed in terms of linear matrix inequalities (LMIs). Examples are provided to demonstrate the reduced conservatism of the proposed stability results.