• Management Science and Financial Engineering
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• v.12 no.2
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• pp.87-110
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• 2006

In a hierarchical road network, all roads can be classified according to their attributes such as speed limit, number of lanes, etc. By splitting the whole road network into the subnetworks of the highlevel and low-level roads, we can reduce the size of the network to be calculated at once, and find a path in the way that drivers usually adopt when searching out a travel route. To exploit the hierarchical property of road networks, we define a convenient path and propose an algorithm for finding convenient paths. We introduce a parameter indicating the driver's tolerance to the difference between the length of a convenient path and that of a shortest convenient path. From this parameter, we can determine how far we have to search for the entering and exiting gateway. We also propose some techniques for reducing the number of pairs of entries and exits to be searched in a road network. A result of the computational experiment on a real road network is given to show the efficiency of the proposed algorithm.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.10a
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• pp.321-333
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• 2005

With the limited frequency spectrum and an increasing demand for cellular communication services, the problem of channel assignment becomes increasingly important. However, finding a conflict free channel assignment with the minimum channel span is NP hard. As demand for services has expanded in the cellular segment, sever innovations have been made in order to increase the utilization of bandwidth. The innovations are cellular concept, dynamic channel assignment and hierarchical network design. Hierarchical network design holds the public eye because of increasing demand and quality of service to mobile users. We consider the frequency assignment problem and the base station placement simultaneously. Our model takes the candidate locations emanating from this process and the cost of assigning a frequency, operating and maintaining equipment as an input. In addition, we know the avenue and demand as an assumption. We propose the network about the profit maximization. This study can apply to GSM(Global System for Mobile Communication) which has 70% portion in the world. Hierarchical network design using GA(Genetic Algorithm) is the first three-tier (Macro, Micro, Pico) model, We increase the reality through applying to EMC (Electromagnetic Compatibility Constraints). Computational experiments on 72 problem instances which have 15${\sim}$40 candidate locations demonstrate the computational viability of our procedure. The result of experiments increases the reality and covers more than 90% of the demand.

• International Journal of Advanced Culture Technology
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• v.2 no.1
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• pp.1-13
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• 2014

In next-generation wireless networks, provisioning of IP-based network architecture and seamless transmission services are very important issues for mobile nodes. For this reason, a mobility management mechanism to support global roaming is highly regarded. These technologies bring a broader life by using a global roaming account through the connection of multiple devices or technology to mobile users; they also provide real-time multimedia services. This paper presents a comprehensive performance analysis of fast handover for hierarchical mobile IPv6 (F-HMIPv6), hierarchical mobile IPv6 (HMIPv6), Proxy Mobile IPv6 (PMIPv6), and fast Proxy Mobile IPv6 (FPMIPv6) using the fluid-flow model and random-walk model. As a result, the location update cost of the PMIPv6 and FPMIPv6 is better than that of HMIPv6 and F-HMIPv6. These results suggest that the network-based mobility management technology is superior to the hierarchical mobility management technology in the mobility environment.

• Journal of Arbitration Studies
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• v.13 no.2
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• pp.489-517
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• 2004

The resolution of the 1993 Uruguay Round and the opening of Korea's construction market in '97 marked the beginning of the globalization of Korea's domestic construction market. Consequently, the process led to changes in contracting procedures, as well as disputes in construction management. With globalization came a rapid realization of reasonable values, which forced the hierarchical vertical relationship between the owners, constructors, and subcontractors into a more equal, horizontal relationship. Once the hierarchical relationship was altered, the late 1990's witnessed a dramatic increase in managerial disagreements, in addition to escalating legal disputes and expenditures. The horizontal relationship was a new concept and brought forth many complexities. Unfortunately, because all of this was new, management of construction disputes was elementary at best. Anticipation of disputes is the key to effective dispute management. This includes thorough reviews of contract documents, document management, construction records, and checklists. Also necessary is the education of owners and contractors with pertinent knowledge concerning dispute management. The following paper focuses on the importance of observing construction disputes in order to facilitate management thereof.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.5
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• pp.187-198
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• 2008

This paper develops a framework for efficient resource management within the grid service environment. Resource management is the core element of the grid service; therefore, GridRMF(Grid Resource Management Framework) is modeled and developed in order to respond to such variable characteristics of resources as accordingly as possible. GridRMF uses the participation level of grid resource as a basis of its hierarchical management. This hierarchical management divides managing domains into two parts: VMS(Virtual Organization Management System) for virtual organization management and RMS(Resource Management System) for metadata management. VMS mediates resources according to optimal virtual organization selection mechanism, and responds to malfunctions of the virtual organization by LRM(Local Resource Manager) automatic recovery mechanism. RMS, on the other hand, responds to load balance and fault by applying resource status monitoring information into adaptive performance-based task allocation algorithm.

• Journal of the Korean Data and Information Science Society
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• v.20 no.5
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• pp.895-903
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• 2009

The penalized partial likelihood based on restricted maximum likelihood method has been widely used for the inference of frailty models. However, the standard-error estimate for frailty parameter estimator can be downwardly biased. In this paper we show that such underestimation can be corrected by using hierarchical likelihood. In particular, the hierarchical likelihood gives a statistically efficient procedure for various random-effect models including frailty models. The proposed method is illustrated via a numerical example and simulation study. The simulation results demonstrate that the corrected standard-error estimate largely improves such bias.

• Journal of the Korean Operations Research and Management Science Society
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• v.18 no.1
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• pp.1-18
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• 1993

The family disaggregation model of hierarchical production planning (HPP) is the problem of (0 -1) mixed integer programming that minimizes the total sum of setup costs and inventory holding costs over the planning horizon. This problem is hard in a practical sense since optimal solution algorithms have failed to solve it within reasonable computation times. Thus effective familoy disaggregation algorithm should be developed for HPP. The family disaggregation algorithm developed in this paper consists of the first stage of finding initial solutions and the second stage of improving initial solutions. Some experimental results are given to verify the effectiveness of developed disaggregation algorithm.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1998.10a
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• pp.330-330
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• 1998

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1991.10a
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• pp.338-338
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• 1991

• International conference on construction engineering and project management
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• 2015.10a
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• pp.183-187
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• 2015

The Risk Management (RM) is applied for managing uncertainty of project. In this circumstance, the competences of RM have a direct effect on the performance of its application. Especially, as the RM, one of the project management areas, is a peopleoriented management field, the individual behavioral competences are significant for a risk manager. Therefore, this paper describes the development of individual behavioral competences for construction project risk manager. For this, the research classifies the individual behavioral competences of RM. And, the Exploratory Factor Analysis (EFA) are applied to verify a validity of the competences. Likewise, a reliability analysis using Cronbach's alpha values is performed to test internal consistency. Based on the results, the authors carry out the Focus Group Interview (FGI) on expert panels of construction RM to confirm the hierarchical model of the individual behavioral competences. It is concluded that the proposed hierarchical model of individual behavioral competences helps construction companies to diagnose the competences of their project risk manager for progressing.