• The Journal of Asian Finance, Economics and Business
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• v.5 no.2
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• pp.139-149
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• 2018

In the contemporary era of smart tourism, travelers face more accommodation options than ever before. The rapid expansions of alternative accommodation sector are partially owing to the growth of electronic commerce and the rise of online intermediary platforms. Online travel agencies serve as a critical distribution channel for tourism sectors, and the significance is further increased for small and micro entrepreneurs whose direct communication channels are scarce. Considering the holistic process of customer experience started with a third-party online intermediary, this study explores basic and extended attributes of small and medium-sized alternative accommodation where the comparative value is created. In order to achieve the objective, a research design was developed to synthesize the qualitative evidence. The synthesis encompasses both theoretical and practical perspectives, from a systematic review and opinions of academic professionals to an in-depth interview with an industry expert and the current practices of online travel agencies. This study suggests that the sources of value creation for alternative accommodation are not always consistent with those of the traditional. Accounting for the temporal and spatial dynamics in customer experience, the findings of this study provide insights on the comparative value of alternative accommodation, to both academic and industry audiences.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.471-479
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• 2012

In cellular femto systems, femto Base stations(f-BSs) can be installed unnecessarily and overcrowded in small areas. This will cause an interference problem and it can impact on the capacity, blocking probability, and coverage of femtocells in the shared channel systems. In this paper, we propose a load distribution scheme by using forced handover and probabilistic subchannel scheduling policy to resolve the problem. The proposed scheme operates in distributed manner though communication with neighboring f-BSs, and includes self-detection of overcrowded area and radio resource management based on measurements. We evaluate the performance of the proposed scheme in terms of average cell throughput and average throughput per users.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5A
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• pp.457-463
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• 2011

This paper proposes theorthogonal reference vectors selection method of the subspace interference alignment. The proposed method selects multiple orthogonal reference vectors instead of using one reference vector for all users at the same time. The proposed scheme selects a reference vector which maximizes a sum-rate for a certain cell, generates orthogonal vectors to the previous selected vector and selects the one of orthogonal vectors whose sum rate is maximized for each cell. Larger channel gain and sum-rate than the previous method can be obtained by selection degree of freedom. The computer simulation demonstrates the proposed method gives higher sum-rate compared with that of the previous reference vector selection method.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.629-633
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• 2008

Frequently occurring flood and drought have increased the necessity of an effective water resources control and management of river flows. Therefore, the simulation of the flow distribution in natural rivers is very important to the solution of a wide variety of practical flow problems in water resources engineering. Usually in many flow problems, two-dimensional approach can provide good estimates of complex flow features in the flow around islands and obstructions, flow at confluence and flow in braided channel. The objective of this study is to examine validation of developed an accurate and robust two-dimensional finite element method with wet and dry simulation in complex natural rivers. Milyang river, and Kumho river and Keum river were performed for tests. The results were compared with those of existing model. The suggested model displayed reasonable flow distribution compared with existing model in dry area for application of natural river flow. As a result of this study, the developed general two-dimensional model provide a reliable results for flow distribution of wet and dry domain, it could be further developed to basis for extending to water quality and sediment transport analysis.

• 한국디지털정책학회:학술대회논문집
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• 2004.05a
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• pp.675-690
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• 2004

A new way of teaching on the Internet can be called Web Based Instruction (WBI). WBI goes far above and beyond teaching in the school. It will have an impact on overall educational activity that will dramatically change many existing educational processes and persuade most teachers to change their conventional teaching methods. The main purposes of this research were to make a comparative study of academic achievement between expository lecture and web-based instruction, and to identify the difference in academic achievement of learning tasks in pre- and post- experiments of WBI. The conclusions of this study were as follows. First. there are no differences in academic achievement between expository lecture and teacher- directed web based instruction. Second, there are no differences in academic achievement between expository lecture and teacher-assisted web based instruction. Third, there is difference in academic achievement between teacher-assisted web based instruction and teacher-directed web based instruction. Fourth, there are no differences in academic achievement of reading tasks in pre- or post- experiments of teacher-directed web based instruction. On the basis of the research results and discussion, we finally present a Web-Application-Model (WAM) to encourage the usage of Internet as a useful teaching channel.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.2
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• pp.103-111
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• 2011

Recently, wireless mesh networks are used in various application areas. However, wireless mesh networks have limited bandwidth by the wireless transmission property, and have severe throughput degradation in multi-hop transmission in single channel wireless mesh networks. To solve this problem and support QoS, a lot of routing protocols have been proposed in mesh networks. In this paper, we propose a wireless mesh networks architecture with MPLS for QoS service. The path and traffic management from the application could be independent from QoS routing protocols by using the MPLS in wirelss mesh networks. In this paper, we design a MPLS-based mesh router with IEEE 802.11e for traffic differentiation and investigate the operation by implementation and test.

• Journal of Hydrogen and New Energy
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• v.18 no.4
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• pp.422-431
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• 2007

Polymer electrolyte membrane fuel cell(PEMFC) is very interesting power source due to high power density, simple construction and operation at low temperature. But it has problems such as high cost, improvement of performance and effect of temperature. These problems can be approached to be solved by using mathematical models which are useful tools for analysis and optimization of fuel cell performance and for heat and water management. In this paper, the present work is to develop an electrochemical model to examine the electrochemical process inside PEM fuel cell. A complete set of considerations of mass, momentum, species and charge is developed and solved numerically with proper account of electrochemical kinetics. When depth of gas channel becomes thinner, diffusion of reactant makes well into gas diffusion layer(GDL) and the performance increases. Although at low current region there is little voltage difference between experimental data of PEM fuel cell and numerical data. When the porosity size of gas diffusion layer for PEM fuel cell is bigger, oxygen diffusion occurs well and oxygen mass fraction appears high in catalyst layer.

• Journal of Information Technology Applications and Management
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• v.15 no.1
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• pp.261-270
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• 2008

Wireless Mesh Networks (WMNs) have emerged as one of the new hot topics in wireless communications. WMNs have been suggested for use in situations in which some or all of the users are mobile or are located in inaccessible environments. Unconstrained transmission in a WMN may lead to the time overlap of two or more packet receptions, called collisions or interferences, resulting in damaged useless packets at the destination. There are two types of collisions; primary collision, due to the transmission of the stations which can hear each other, and hidden terminal collision, when stations outside the hearing range of each other transmit to the same receiving stations. For a WMN, direct collisions can be minimized by short propagation and carrier sense times. Thus, in this paper we only consider hidden terminal collision while neglecting direct collisions. To reduce or eliminate hidden terminal collision, code division multiple access (CDMA) protocols have been introduced. The collision-free property is guaranteed by the use of spread spectrum communication techniques and the proper assignment of orthogonal codes. Such codes share the fixed channel capacity allocated to the network in the design stage. Thus, it is very important to minimize the number of codes while achieving a proper transmission quality level in CDMA WMNs. In this paper, an efficient heuristic code assignment algorithm for eliminating hidden terminal collision in CDMA WMNs with general topology.

• International Commerce and Information Review
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• v.11 no.1
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• pp.177-197
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• 2009

In this study we presented the plans to activate the Internet Shopping Mall for GWmart under its present situation recording a rapid growth in sales and recognized as a local new distribution channel since its early stage, using the analysis that affects the purchases of consumers. On studying the reliance of a shopping mall, only the shopping mall image and the efficiency in providing information are significant. Regarding the concentration on the shopping site by shoppers, what becomes significant are the efficiency in providing information and the convenience in searching for products, which is one of the important factors in increasing sales, does not affect the reliance of a shopping mall and the concentration on the shopping site by shoppers. Therefore, this finding suggests that it is not easy to access the internet shopping mall when consumers go shopping for certain products. Because of this, it is necessary to change the design and structure of internet shopping mall to focus on the consumers. Moreover, this study showed that the efficiency in providing information to customers and the image of the shopping mall do not affect the consumers' intention to purchase, which means that shopping mall lacks in its information service and the management of its structure. To address this, it is required to advance the User Interface and contents of internet shopping mall.

• Journal of Communications and Networks
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• v.7 no.3
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• pp.337-352
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• 2005

In this paper, a fuzzy logic implementation of the random early detection (RED) mechanism [1] is presented. The main objective of the proposed fuzzy controller is to reduce the loss probability of the RED mechanism without any change in channel utilization. Based on previous studies, it is clear that the performance of RED algorithm is extremely related to the traffic load as well as to its parameters setting. Using fuzzy logic capabilities, we try to dynamically tune the loss probability of the RED gateway. To achieve this goal, a two-input-single-output fuzzy controller is used. To achieve a low packet loss probability, the proposed fuzzy controller is responsible to control the $max_{p}$ parameter of the RED gateway. The inputs of the proposed fuzzy controller are 1) the difference between average queue size and a target point, and 2) the difference between the estimated value of incoming data rate and the target link capacity. To evaluate the performance of the proposed fuzzy mechanism, several trials with file transfer protocol (FTP) and burst traffic were performed. In this study, the ns-2 simulator [2] has been used to generate the experimental data. All simulation results indicate that the proposed fuzzy mechanism out performs remarkably both the traditional RED and Adaptive RED (ARED) mechanisms [3]-[5].