• Journal of Korea Multimedia Society
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• v.7 no.5
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• pp.689-697
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• 2004

Rapid advances in mobile computing and the availability of wireless communications will soon provide mobile users with the ability to access data regardless of the location of the user or of the data. SRA(Static Replica Allocation) that is traditional scheme has been used for the replication method on the server. This replicates the data on the replica server after a moving host has been transferred to the cell. This strategy is simple and can easily relocate data. However, if a mobile user does not exist in the cell, the replicated data can be deleted in order to maintain data consistency. In addition to, if the mobile host leaves from replicated cell, it is difficult to access data in terms of replication route. Therefore, this paper proposes a new method of relocation based on data consistency strategy called USRAC(User Selection Replica Allocation based on Consistency) and also analyzes access cost according to the moving rate of mobile users, according to the access rate of mobile hosts, and according to the number of cells of mobile users and mobile hosts.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.12
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• pp.907-917
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• 2006

In this paper, we propose a strategy to improve fault-tolerance and scalability of replicated services in mobile agent systems by applying an appropriate passive replication protocol for each replicated service according to whether the service is deterministic or non-deterministic. For this purpose, two passive replication protocols, PRPNS and PRPDS, are designed for non-deterministic and deterministic services respectively. They both allow visiting mobile agents to be forwarded to and execute their tasks on any node performing a service agent, not necessarily the primary agent. Especially, in the protocol PRPDS, after a backup service agent has received each mobile agent request and obtained its delivery sequence number from the primary service agent, the backup is responsible for processing the request and coordinating with the other replica service agents. Therefore, our strategy using the two proposed protocols can promise high scalability of replicated services a large number of mobile agents attempt to access in mobile agent systems. Our simulation results show that the proposed strategy performs much better than the one using only the traditional passive replication protocol.

• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.265-275
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• 2002

A default server strategy is a very popular scheme for managing location and state information of mobile hosts in cellular networks. But the communication cost increases if the call requests are frequent and the distant between the default server and the client is long. Still more any connection to a mobile host cannot be established when the default server of the destination mobile host fails. These problems can be solved by replicating default server and by letting nearest replicated default server process the query request which is sent from a client. It is important to allocate replicated default servers efficiently in networks and determine the number of replicated default servers. In this paper, we suggest and evaluate a default server replication strategy to reduce communication costs and to improve service availabilities. Furthermore we propose and evaluate an optimized allocation algorithm and an optimal replication degree for replicating: dofault servers in nn grid networks and binary tree networks.

• Journal of the Korean Operations Research and Management Science Society
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• v.14 no.1
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• pp.88-96
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• 1989

General measure in the reliability is the k-terminal reliability, which is the probability that the specified vertices are connected by the working edges. To compute the k-terminal reliability components are usually assumed to be statistically independent. In this study the modeling and analysis of the k-terminal reliability are investigated when dependency among components is considered. As the size of the network increases, the number of the joint probability parameter to represent the dependency among components is increasing exponentially. To avoid such a difficulty the structured-event-based-reliability model (SERM) is presented. This model uses the combination of the network topology (physical representation) and reliability block diagram (logical representation). This enables us to represent the dependency among components in a network form. Computational algorithms for the k-terminal reliability in SERM are based on the factoring algorithm Two features of the ractoring algorithm are the reliability preserving reduction and the privoting edge selection strategy. The pivoting edge selction strategy is modified by two different ways to tackle the replicated edges occuring in SERM. Two algorithms are presented according to each modified pivoting strategy and illustrated by numerical example.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.12
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• pp.3133-3151
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• 2012

The optimal price strategy selection of two bounded rational cognitive mobile virtual network operators (MVNOs) in a duopoly spectrum sharing market is investigated. The bounded rational operators dynamically compete to sell the leased spectrum to secondary users in order to maximize their profits. Meanwhile, the secondary users' heterogeneous preferences to rate and price are taken into consideration. The evolutionary game theory (EGT) is employed to model the dynamic price strategy selection of the MVNOs taking into account the response of the secondary users. The behavior dynamics and the evolutionary stable strategy (ESS) of the operators are derived via replicated dynamics. Furthermore, a reward and punishment mechanism is developed to optimize the performance of the operators. Numerical results show that the proposed evolutionary algorithm is convergent to the ESS, and the incentive mechanism increases the profits of the operators. It may provide some insight about the optimal price strategy selection for MVNOs in the next generation cognitive wireless networks.

• Journal of KIISE:Software and Applications
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• v.34 no.5
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• pp.487-501
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• 2007

To achieve high resource utilization for multi-issue DSPs, production compiler commonly includes variants of iterative modulo scheduling algorithm. However, excessive cyclic data dependences, which exist in communication and media processing loops, unduly restrict modulo scheduling freedom. As a result, replicated functional units in multi-issue DSPs are often under-utilized. To address this resource under-utilization problem, our paper describes a novel compiler preprocessing strategy for effective modulo scheduling. The preprocessing strategy proposed capitalizes on two new transformations, which are referred to as cloning and dismantling. Our preprocessing strategy has been validated by an implementation for StarCore SC140 DSP compiler.

• The Transactions of the Korea Information Processing Society
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• v.4 no.7
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• pp.1694-1705
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• 1997

In the future mobile computing environment, it will be generalized that a mobile host with portable Laptop of Palmtop accesses to database through wireless communication channel. For solving the problems which are caused from low bandwidth of wireless communication, mobile hosts cache the datum used frequently on them. Thus the mobile hosts must always retain the cache consistency for the correctness of the cached datum. the cache consistency is mainly affected from the unrestricted host mobility and the disconnection of the communication between mobile hosts and mobile support station. In this situation, the strategy to retain efficiently cache consistency is required. In this paper, we propose a strategy using updatable message for retaining the cache consistency, in the mobile computing environment, with replicated database supporting 2 phase commit protocol. This strategy makes use of a updatable message to resolve the cache consistency problem, since mobile host crosses the boundary of cell. In using of this updatable, it find out and cache only the update data of missing invalidation message. As a result, the proposed strategy utilizes network bandwidth efficiently because it is not need to delete all the cached datum with any datum change.

• Journal of the military operations research society of Korea
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• v.28 no.1
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• pp.47-66
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• 2002

Instead of using signal-to-noise ratio, we attempt to optimize both the mean and variance responses using dual response optimization technique. The alternative experimental strategy analyzes a robust parameter design problem to obtain the best settings that give a target condition on the mean while minimizing its variance. The mean and variance are treated as the two responses of interest to be optimized. Unlike to the crossed array and combined array approaches, our experimental setup requires replicated runs for each control factor's treatment under noise sampling. When the postulated response models are true, they enable the coefficients to be estimated and the desired performance measure to be analyzed more efficiently. The procedure and illustrative example are given for the dual response optimization techniques of nonlinear goal programming.

• Journal of Digital Convergence
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• v.11 no.10
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• pp.263-275
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• 2013

M&A is an important strategic decision made to ensure the competitiveness of companies and cases of M&A have been increasing in recent years. But the success of an M&A is not assured. In order to succeed, there should first be a well managed strategic leadership by the CEO and an integration strategy. Companies need also to overcome the resistance to change among members. A successful example of an M&A is that of LG Chem and Hyundai Petrochemical. By using this M&A as a case study, the influence of the CEO's Strategic Leadership, and the Integration Strategy on Resistance, Acceptance and Performance were assessed. For this study, research was conducted on CEO Strategic Leadership and Integration Strategy before members of LG Chem (DAESAN PLANT) were interviewed on the M&A's implementation by LG Chem's HR staff, management and members. The results show that CEO strategic leadership and the integration strategy are major change drivers and that they are important to the early stabilization of M&A companies. Finally, suggestions are made as to how such success may be replicated for other companies undergoing M&A in the future.

• Journal of Distribution Science
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• v.14 no.6
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• pp.81-87
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• 2016

Purpose - In recent, a research finds that advanced selling can influence a consumer's choice(Kim et al., 2013). Advanced selling is defined as the new product launching strategy which company allows consumers to preorder new product before its release(Chu & Zhang, 2011). Prior researches have focused on the benefits of advanced selling(e.g., information gathering for demand prediction, an advantage for pricing strategy, and so on) for companies using this strategy(Chen, 2001; Chu & Zhang, 2011; Li & Zhang, 2013; Tang et al., 2004; Xie & Shugan, 2009). However, Kim et al.(2013) find it can also influence a consumer's choice. In detail, they suggest that when consumers use advanced selling, they are likely to prefer high-performance options rather than low-price options based on construal level theory(Trope & Liberman, 2003). In this paper, we tried to expand the prior researches for finding the mechanism of the influence of advanced selling on a consumer's choice. The purpose of this research is to test the mediating effect on the influence of advanced selling. Research design, data, and methodology - To find the mechanism of the influence of advanced selling, we designed an experiment for testing mediation effect. we recruited 93 students from a university. We assigned participants into one of two groups using randomization method. The participants with each group were given a scenario describing the sales strategy. Finally, they made a choice between high-performance option and low-price option. Sequentially, they also responded some questions for testing mediation effect. Results - First, we replicated prior research to test the influence of advanced selling. As a result, we could find that consumers prefer the high-performance option when they preorder it to purchase at the time of consumption. Thus, the replication result is the same as prior research. Second, we tested that advanced selling can influence the perception of temporal distance. The results confirmed that consumers perceived longer temporal distance in advanced selling condition(β = 1.575, SE = 0.272, p < 0.001). Third, we predicted that temporal distance can increase the importance of desirable attributes and decrease the importance of feasible attributes. The results suggested that temporal distance decreased significantly the importance of attributes related to feasibility(β = -0.19, SE = 0.07, p < 0.01), however, it had non-significant effect on increasing the importance of desirable attributes. Finally, we used Sobel-test for testing mediation effect, and it confirmed that the importance of feasible attributes had mediating role of the influence of advanced selling(Sobel test statistic = -2.110, SE = 0.111, p < 0.05). Conclusions - In this paper, we tried to find the mechanism of the influence on advanced selling from a consumer's choice. With an experiment, we confirmed that the importance of feasible attributes could mediate the effect on advanced selling. Therefore, we suggested some theoretical and practical contributions from this research. Finally, we discussed research limitations and suggested future research topics.