• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.4
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• pp.365-371
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• 1990

In this paper, the authors calculate GDOP(Geometric Dilution of Precision) with the mast and slave transmitting stations at the past and present and simulation positions in the 9970 chain and 5970 chain of the loran C system, and analyzed variations of the GDOP and effective ranges in accordance with the shifting of transmitting stations. The results obtained are as follows; 1) The line 3.0 of equi-GDOP map that the Z slave station of 9970 chain is Guam island is falled on with line 2.0 of it's map that it is Yap island approximately, and units of GDOP of calculating with Guam island are increased then them with Yap island on the south parts of mast station. 2) If the control right of Z slave station of 9970 chain could be not transfered to japan and be closed on account of the territorial problems, the units of GDOP to calculate without it's station at any positions are very increased and the accuracy is down on the south parts of mast station. The line 5.0 of it's map is falled on with line 2.0 in case of Yap island, its Z station, and line 3.0 in case of Guam island with Z slave station approximately. 3) The X slave station of 9970 chain and 5970 chain are required rearrangement for the purpose of accurating position fix and expending service area in view of propagation route of wave and arrangement of transmitting station.

• Journal of Communications and Networks
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• v.11 no.2
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• pp.175-186
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• 2009

A new medium access control (MAC) scheme embedding physical channels into multiband carrier sense multiple access/collision avoidance (CSMA/CA) networks is proposed to provide strict quality of service (QoS) guarantee to high priority users. In the proposed scheme, two priority classes of users, primary and secondary users, are supported. For primary users physical channels are provided to ensure strict QoS, whereas secondary users are provided with best-effort service using CSMA/CA modified for multiband operation. The performance of the proposed MAC scheme is investigated using a new multiband CSMA/CA Markov chain model capturing the primary user activity and the operation of secondary users in multiple bands. The throughput of secondary users is obtained as a function of the primary user activity and other CSMA/CA parameters. It is shown that the new MAC scheme yields larger throughput than the conventional single-band CSMA/CA when both schemes use the same bandwidth.

• Journal of Information Technology Applications and Management
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• v.21 no.4
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• pp.225-245
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• 2014

ICT based convergence application is one of the most prevalent industrial issue these days. Despite of criticalness and potential economic opportunities of the ICT based convergence, theoretical research to analyze the feasibility and estimate the economic impact of the application is rather limited. This paper is intended to fill this research gap. In this respect, we develop theoretical framework to quantitatively estimate the differential benefits of convergent applications, which necessarily include underling ICT technology's contribution attributes extractions, and resulting value increments engendered from user's process effectiveness when ICT based service application is adopted. The research model to assess the differential value of the ICT based service application is developed, grounded on theoretical framework of TPC (Technology-to-performance chain) and contingency fit theories. Scenario based survey method is adopted, and SmartPLS 2.0. is used for statistical analysis of the structural equation model using 312 questionnaire. Valid statistical results are presented to provide useful insight.

• 한국디지털정책학회:학술대회논문집
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• 2004.05a
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• pp.525-544
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• 2004

The Purpose of this study is to examine logistics characteristics related to electronic commerce and to suggest improvement of logistics Service in electronic commerce. This paper concerns the logistics functions which are essential for completing a commerce process even under the EC environment and provides ways to improve the logistics performance. Electronic commerce have introduced two scenes; dramatic change of the existing distribution surroundings and noticeable achievement of the economic advance and social efficiency. But, in the same scene, electronic commerce can be a threat to business condition, especially logistics management. It suggests that for activation of EC it is necessary to strengthen the strategic alliances, introduce GPS and use the third party logistics positively to prepare for the settlements of traffic problems, support the introduction of integrated logistics service and logistics information system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.2
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• pp.84-91
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• 2002

The progress of information technology triggered the rapid progress of tourism industry and the industry has now grown to be the biggest and the highest value added producing industry. Tourism industry is characterized by its high information dependency and is subject to the frequent changes of schedule. Therefore, dynamic cooperations between the service provider and the service agent is essential. One of the latest trend in information technology is the popular adoption of XML as the standard means of document exchange in the internet environment. This paper proposes a supply chain management system which enhances the productivity and customer satisfaction in the tourism industry by exploiting the exchange of information in XML among the tourism society, which consists of the producer, the agents, and the consumer. This Paper is especially addressed to the applicability of e-SCM for the productivity enhancement in the tourism industry, which is known as the leading service industry in the internet environment.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.4
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• pp.99-106
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• 2017

With the advent of virtual money such as bit coins, interest in the block chain is increasing. Block Chain is a technology that supports Distributed Ledger and is a versatile technology applicable to various fields. Currently, the block chain is conducting research for various applications such as virtual money, trade finance, marketplace, power market, image contents service, and IoT. The technologies that make up the block chain are smart contract, digital signature/hash function and consensus algorithm. And these technologies operate on P2P networks. In this paper, we have studied e-mail system based on the ethereum which is one of the block chain based technologies. Most legacy mail systems use SMTP and the POP3/IMAP protocol to send and receive e-mail, and e-mail use S/MIME to protect the e-mail. However, S/MIME is vulnerable to DDoS attacks because it is configured centrally. And it also does not provide non-repudiation of mail reception. To overcome these weaknesses, we proposed an e-mail system model based on ethereum. The proposed model is able to cope with DDoS attack and forgery prevention by using block chain based technology, and reliable recording and management among block chain participants are provided, so that it is possible to provide a non-repudiation function of e-mail transmission and reception.

• Asian Journal of Business Environment
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• v.2 no.2
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• pp.35-39
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• 2012

Purpose - Today's world is rapidly changing due to swift changes in organization's infrastructures and supply chain is becoming an important factor which affects the organization's global competitiveness. Research design / data / methodology - Researchers indicated that environment uncertainty is considered an external driving force to establish a unique supply chain. Market competition, reducing the gap of performance and quality between the products are compelling the practitioners and researcher to change the paradigm of managing the business processes effectively and efficiently. Results - In old times, supply chain of any organization was measured on the basis of inventory turns, defect rats, lead times, stock buffering and service level. But, Lee H.L. in 2004, published an article in Harvard Business Review who proposed three A (Adaptable, Agile and Aligned) termed as "Triple-A" of successful supply chain. Conclusions - He claimed that organizations can compete through the creation of Triple-A supply chain. Hence, the basic aim of this review paper is to develop basic insights regarding what is Triple-A of supply chain, its importance and functioning in today's competitive world.

• The Journal of Asian Finance, Economics and Business
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• v.4 no.2
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• pp.69-74
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• 2017

The purpose of this research is to be acquainted with the awareness and approval of halal supply chain among Indian manufacturers and distribution network members for haulage and warehousing activities from the perception of respective service suppliers. A total of 20 respondents, which consist of 10 transportation companies and 10 warehousing companies from the State of Andhra Pradesh in India were selected for the study by using purposive sampling method. The principal focal points of the discussions are on awareness and adoption of halal transportation and warehousing services chosen for the study in the comprehensive halal supply chain. A total of 90 percent and 70 percent of respondents from the transportation and warehousing companies respectively agreed that they know only about the concept of halal but do not have any exposure and ken on the halal supply chain. However, findings of this research won't have extensive validity in the market, gaining an enough familiarity with the halal supply chain in the Indian social context is of immense importance. This is a pioneering attempt aimed to investigate the awareness and adoption levels of halal supply chain among Indian businessmen which are precious for supply chain companies to customize their services in the country as well to the world of academia.

• Journal of KIISE
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• v.44 no.7
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• pp.719-725
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• 2017

To reduce management costs and improve performance, the European Telecommunication Standards Institute (ETSI) introduced the concept of network function virtualization (NFV), which can implement network functions (NFs) on cloud/datacenters. Within the NFV architecture, NFs can share physical resources by hosting NFs on physical nodes (commodity servers). For network service providers who support NFV architectures, an efficient resource allocation method finds utility in being able to reduce operating expenses (OPEX) and capital expenses (CAPEX). Thus, in this paper, we analyzed the network service chain embedding problem via an optimization formulation and found a close-optimal solution based on the Markov approximation framework. Our simulation results show that our approach could increases on average CPU utilization by up to 73% and link utilization up to 53%.

• Journal of Korea Port Economic Association
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• v.28 no.3
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• pp.91-110
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• 2012

In the modern management literature, knowledge has been recognized as a new strategic resource enabling a firm to create its competitiveness. Shipping companies under fierce competitive structure need to pay attentions to the utility of knowledge management. A shipping firm may develop its unique service capability by classifying, sharing, and transferring the data, information and knowledge obtained from both inside and outside its global service network. The current study attempts to analyze influential relationships between liner shipping firms' knowledge management and service capabilities. In order to achieve this goal, this study designed a knowledge chain model measuring shipping companies' knowledge management levels and tested its validity and reliability based on a total of 80 replied questionnaires from national and foreign liners. The empirical result presents that supportive and primary activities composing a knowledge chain could exert significant positive influences on the enforcement of shipping service capabilities. This research shows that the utility of knowledge management is adoptable in the maritime industry, and recommends that shipping firms should recognize strategic importance of knowledge and actively pursue knowledge management at an entire firm level.