• The Transactions of the Korea Information Processing Society
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• v.5 no.10
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• pp.2627-2640
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• 1998

In this paper, we analyze the performance of the virtual cell system[1] for the transmission of IP datagrams in mobile computer communications. A virtual cell consistsof a group of physical cells shose base stationsl are implemented b recote bridges and interconnected via high speed datagram packet switched networks. Host mobility is supported at the data link layer using the distributed hierachical location information of mobile hosts. Given mobility and communication ptems among physical cells, the problem of deploying virtual cells is equivalent to the optimization cost for the entire system where interclster communication is more expesive than intracluster communication[2]. Once an iptimal partitionof disjoint clusters is obtained, we deploy the virtual cell system according to the topology of the optimal partition such that each virtual cell correspods to a cluser. To analyze the performance of the virtual cell system, we adopt a BCMP open multipel class queueing network model. In addition to mobility and communication patterns, among physical cells, the topology of the virtual cell system is used to determine service transition probabilities of the queueing network model. With various system parameters, we conduct interesting sensitivity analyses to determine network design tradeoffs. The first application of the proposed model is to determine an adequate network bandwidth for base station networking such that the networks would not become an bottleneck. We also evaluate the network vlilization and system response time due to various types of messages. For instance, when the mobile hosts begin moving fast, the migration rate will be increased. This results of the performance analysis provide a good evidence in demonsratc the sysem effciency under different assumptions of mobility and communication patterns.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.5
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• pp.62-70
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• 2016

Ensuring walkability in a city where pedestrians and vehicles coexist is an issue of critical importance. The relative relationship between vehicle transit and walkability improvements complicates the evaluation of walkability, which thus necessitates the formation of a quantitative standard by which a methodological measurement of walkability can be achieved inside the pedestrian network. Therefore, a model is determined whereby quantitative indices such as, but not limited to, experiences of accessibility, mobility, and convenience within the network are estimated. This research proposes the integration of space syntax theory and the logit path choice model in the evaluation of walkability. Space syntax theory assesses adequacy of the constructed pedestrian network through calculation of the link integration value, while the logit model estimates its safety, mobility, and accessibility using probability. The advantage of the integrated model hence lies in its ability to sufficiently reflect such evaluation measures as the integration value, mobility convenience, accessibility potential, and safety experienced by the demand in a quantitative manner through probability computation. In this research, the Dial Algorithm is used to arrive at a solution to the logit model. This process requires that the physical distance of the pedestrian network and the perceptive distance of space syntax theory be made equivalent. In this, the research makes use of network expansion to reflect wait times. The evaluation index calculated through the integrated model is reviewed and using the results of this sample network, the applicability of the model is assessed.

• Journal of Korean Society of Transportation
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• v.21 no.2
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• pp.95-105
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• 2003

Because the basic assumptions of deterministic user equilibrium assignment that all network users have perfect information of network condition and determine their routes without errors are known to be unrealistic, several stochastic assignment models have been proposed to relax this assumption. However. it is not easy to solve such stochastic assignment models due to the probability distribution they assume. Also. in order to avoid all path enumeration they restrict the number of feasible path set, thereby they can not preciously explain the travel behavior when the travel cost is varied in a network loading step. Another problem of the stochastic assignment models is stemmed from that they use heuristic approach in attaining optimal moving size, due to the difficulty for evaluation of their objective function. This paper presents a logit-based stochastic assignment model and its solution algorithm to cope with the problems above. We also provide a stochastic user equilibrium condition of the model. The model is based on path where all feasible paths are enumerated in advance. This kind of method needs a more computing demand for running the model compared to the link-based one. However, there are same advantages. It could describe the travel behavior more exactly, and too much computing time does not require than we expect, because we calculate the path set only one time in initial step Two numerical examples are also given in order to assess the model and to compare it with other methods.

• Korean Journal of Childcare and Education
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• v.9 no.3
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• pp.309-342
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• 2013

This study analyzes the development process of national childcare curriculum, the goal and contents of the 3rd Standard Childcare Curriculum for Childcare Center in order to suggest the successful way to improve the 3rd Standard Childcare Curriculum. After its establishment in 2007, significant changes had been made to the Standard Childcare Curriculum in order to improve the quality of childcare: Nuri Curriculum for age 5 in 2011, second revision of Standard Childcare Curriculum in 2012, creation of Nuri Curriculum for age 3-4, revision of Nuri Curriculum for age 5, and third Standard Childcare Curriculum in 2013. The third Standard Childcare Curriculum is specified as infants age 0-1, age 2, and age 3-5(Nuri Curriculum). For a successful settlement of the 3rd Standard Childcare Curriculum, first, we need in depth analysis of the Nuri Curriculum by age classification. Second, there should be an effort to link the Standard Childcare Curriculum with elementary school education in practical manner. Further, we need to solve the payroll gap problem between teachers in charge of Nuri Curriculum and infant classes. Finally, teachers should be given more respect, and equivalent teaching qualification standard should be made between childcare and early childhood education.

• The Journal of the Korea Contents Association
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• v.22 no.4
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• pp.592-608
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• 2022

This study conducted a group reminiscence program for the elderly who use the elderly daycare center. And this study verified the effectiveness of the elderly's mental health related quality of life to identify the relationship between the participating elderly and the non-participating elderly in a group reminiscence program. To this end, in order to examine the effectiveness of a group reminiscence programs for the elderly using the daycare center on MHRQoL, and the difference between the experimental group and the control group was compared with the non-equivalent control group pre-post test design. The research results are as follows. First, the experimental group that conducted the group reminiscence program in this study had a higher quality of life than the control group that did not participate the group reminiscence program. Second, significant results were found in vitality and mental health in the sub-factors of MHRQoL of the experimental group, and emotional role restriction and social function did not show significant results. Based on the results of this study, to develop and improve programs that encompass the entire sub-areas of MHRQoL, and to implement programs that positively affect the psycho-social intervention for the elderly persons. Finally, it was suggested to link and cooperate with senior welfare centers and general social welfare centers.