• Journal of KIISE:Information Networking
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• v.33 no.3
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• pp.277-287
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• 2006

Most of the existing broadband access networks based on DSL, cable modem, and Ethernet support the best-effort internet access service, and adopt the flat rate pricing mechanism. It is almost impossible to provide the differentiated communication services, in current broadband access networks, for the different users and/or the different application services. Currently, however, the advances in multimedia, communication, and security technologies push the interactive and/or streaming multimedia services and VPN services to be widely deployed over Internet, and they require more QoS-sensitive services than the best-effort service. Though various QoS technologies such as RSVP-based IntServ and DiffSern were already developed and under standardization in Internet world, it is impractical to replace the existing QoS-unaware access networks with the QoS-enabled ones at a time to deploy QoS-sensitive services. In this paper, after analyzing current broadband access network architectures and the status of QoS support, we propose a practical approach to support multimedia QoS in the broadband access networks. The approach will be based on the integration of the differentiated pricing and the DiffServ technology. And it will be a step-wise approach to support backward compatibility with the legacy broadband access networks as much as possible.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.10
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• pp.3810-3830
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• 2015

In this paper, we investigate the differential game theoretic approach for distributed dynamic cooperative power control in cognitive radio ad hoc networks (CRANETs). First, a payoff function is defined by taking into consideration the tradeoff between the stock of accumulated power interference to the primary networks and the dynamic regulation of the transmit power of secondary users (SUs). Specifically, the payoff function not only reflects the tradeoff between the requirement for quickly finding the stable available spectrum opportunities and the need for better channel conditions, but also reveals the impact of the differentiated types of data traffic on the demand of transmission quality. Then the dynamic power control problem is modeled as a differential game model. Moreover, we convert the differential game model into a dynamic programming problem to obtain a set of optimal strategies of SUs under the condition of the grand coalition. A distributed dynamic cooperative power control algorithm is developed to dynamically adjust the transmit power of SUs under grand coalition. Finally, numerical results are presented to demonstrate the effectiveness of the proposed algorithm for efficient power control in CRANETs.

• The Journal of Information Systems
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• v.31 no.1
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• pp.115-146
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• 2022

Purpose The purpose of this study is to find meaningful insights using regression analysis to resolve the digital divide between generations. In the analysis process of this study, social network analysis was applied to approach it with a perspective differentiated from the existing statistical techniques. Design/methodology/approach This study used a social network analysis methodology that transforms and analyzes government-led survey data into relational data. First, the cross-sectional data were converted into relational data, and a continuous core-periphery model and multidimensional scaling method were applied. Afterwards, the relationship between various factors affecting the digital divide and the difference in influence were analyzed by generation. Findings According to the network analysis results, it can be seen that all generations commonly use 'information and news search' and 'living information service'. However, it can be seen that the centrally used services of each generation are clearly different from each other, and the degree of linkage between the services is also clearly different. In addition, it can be seen that the relationship between factors influencing the digital divide by generation is also different.

• Journal of Educational Research in Mathematics
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• v.8 no.1
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• pp.41-58
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• 1998

In this paper, we designed an open class teaching model in level-based team arrangements. In this way, teaching lesson plans were newly developed in order to teach students in open classroom environments. Both teachers and students required enough time to be acquainted with the new approach. However, empirical data analyses of mid-term and final examinations as well as survey data mathematical achievements indicated that most of the students have shown interests in mathematical activities and confidences on their mathematical abilities. Furthermore, there were few students who seemed to be isolated from mathematical activities. In particular, most students didn't seem to get lower grades than expected from other teachers who hesitated to apply the new model.

• Korean Journal of Adult Nursing
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• v.21 no.6
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• pp.603-616
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• 2009

Purpose: The purpose of this study was to examine the subjective opinions of first-generation Korean-Americans about survival. Methods: The Q-methodology which provides a method of analyzing the subjectivity of each item was used. The 34 selected Q-statements from each of 38 subjects were classified into a shape of normal distribution using a 9 point scale. The collected data was analyzed using a QUANL/WIN program. Results: Four types of survival attitudes from 38 first-generation Korean-Americans were identified. Type I was a satisfaction type based on belief, Type II was an effort type based on purpose, Type III was an isolation type based on ethnicity, and Type IV was a compromise type based on adaptation. Results of this study indicate that approaches to a minority's survival strategies need to be differentiated taking this typology and various subject characteristics into account. Conclusion: This information may provide a basic understanding for healthcare providers who work with first-generation Korean-Americans.

• International Commerce and Information Review
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• v.11 no.3
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• pp.311-335
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• 2009

This study investigates the factors barrier the performance of Korean manufacturing firms in China. Also an empirical data use the field survey of Korean manufacturing firms in China. as a result, First, we find that employment-cost factor, that is rising labor costs, a change of occupation is an effect the performance of Korean manufacturing firms in China. Second, business beginning year and by 7 region factor is very significant on the performance of Korean FDI firms in china. And then, Korean corporate investment in China is a desirable form of long-term investment shall be determined. also we know that regions of China, differentiated investment approach is effective. finally, The result shows that FDI to China is need of the long term plan, and In actual use, these FDI should be applied flexibly in china business environment.

• Knowledge Management Research
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• v.7 no.1
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• pp.65-80
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• 2006

Recently, Korean economy is boosted by the active introduction of many venture businesses full of entrepreneurship. It has been widely accepted implicitly that success of the venture business originates from unique style of knowledge management. This assumption looks natural when we consider the fact that success of the venture business heavily depends on differentiated intelligent asset or knowledge. However, such implicit belief has never been tested empirically. To fill the research void like this, this paper proposes an empirical derivation of key success factors from the venture businesses listed in KOSDAQ. To add rigor to our results, we performed regression analysis by using the derived key success factors as independent variables, and introducing organization efficiency, job satisfaction, and accomplishment motivation as dependent variables. Regression results showed that our approach is justified from the statistical perspective.

• Journal of Korean Society of Transportation
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• v.12 no.1
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• pp.43-54
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• 1994

The major concern of this paper is to investigate the properties of a stochastic equilibrium for each model system in terms of a consumer welfare measure. The primary assumption for this study is that a trip-maker would choose the trip from his origin zone which maximizes his personal welfare. This assumption, finally, leads to a singly constrained gravity model. The consumer welfare measure is derived from the concept of expected welfare of randomly sampled trip-makers. Each of the four different models considered in this paper is differentiated depending on the complexity of its model or the definition of its travel function. In this study, three different regions are chosen for the purpose of taking into account the effects of different zone-systems on the properties of a stochastic equilibrium : (i) Archerville region (5 zone) ; (ii) San Francisco Bay regions (30 zones) ; (iii) Houston, TX region (199 zones). It is concluded that almost identical, "global" consumer welfare values can be obtained in some cases of the gravity-type trip distribution models based on a stochastic equilibrium.

• Journal of Information Technology Applications and Management
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• v.17 no.1
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• pp.141-155
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• 2010

We develop an intelligent information system in a multilayer electronic supply chain network. Using the internet for supply chain management (SCM) is a key interest for contemporary managers and researchers. It has been realized that the internet can facilitate SCM by making real time information available and enabling collaboration between trading partners. Here, we propose a multi-agent system to analyze the performance of the elements of a supply network based on the attributes of the information flow. Each layer consists of elements which are differentiated by their performance throughout the supply network. The proposed agents measure and record the performance flow of elements considering their web interactions for a dynamic route selection. A dynamic programming approach is applied to determine the optimal route for a customer in the end-user layer.

• BMB Reports
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• v.48 no.4
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• pp.193-199
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• 2015

Degenerative retinal diseases affect millions of people worldwide, which can lead to the loss of vision. However, therapeutic approaches that can reverse this process are limited. Recent efforts have allowed the possibility of the stem cell-based regeneration of retinal cells and repair of injured retinal tissues. Although the direct differentiation of pluripotent stem cells into terminally differentiated photoreceptor cells comprises one approach, a series of studies revealed the intrinsic regenerative potential of the retina using endogenous retinal stem cells. Muller glial cells, ciliary pigment epithelial cells, and retinal pigment epithelial cells are candidates for such retinal stem cells that can differentiate into multiple types of retinal cells and be integrated into injured or developing retina. In this review, we explore our current understanding of the cellular identity of these candidate retinal stem cells and their therapeutic potential for cell therapy against degenerative retinal diseases. [BMB Reports 2015; 48(4): 193-199]