• Journal of Korea Port Economic Association
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• v.30 no.1
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• pp.73-96
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• 2014

Competitiveness of container ports has been traditionally evaluated by capability of individual ports to provide services to customers or their service quality. However, since container ports are connected by container shipping networks to varying degrees, the status of the ports in liner shipping service networks also determines competitiveness of the ports. Sometimes same ports may play different roles in different forms of shipping networks. Shipping network connections that formulate in container ports therefore have more significant impact on their performance than service capabilities they have. This study aims to explore how the shipping and port network has been structured and changed in the past and to examine the network characteristics of ports using Social Network Analysis(SNA). In this SNA study, nodes in the network are the ports-of-call of the liner shipping services and links in the network are connections realized by vessel movements, such that the liner shipping networks determine the port networks. This study, therefore, investigates the liner shipping networks and through its results demonstrates the network characteristics of the ports that are represented by the four centrality indices. This provides port authorities and terminal operating companies with managerial implications to enhance competitiveness from customers' perspectives.

• Information Systems Review
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• v.19 no.2
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• pp.21-35
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• 2017

The advancement of IT and the "Fourth Industrial Revolution" blurred the boundary between industries. The importance of strategic cooperation between enterprises is emphasized. IT companies must consider their existing business areas and create new territories to drive changes in the industry. They must also secure their competitive edge and manage economic costs to enable them to compete with their global counterparts. By utilizing their resources effectively, these firms can create value through inter-firm cooperation. This study analyzes the collaborative network of global IT companies using social network analysis and examines the effect of this network on firm performance. Collaborative linkages and betweenness centrality, which represent the bridging position of a firm in a network, significantly affect firm performance. This result highlights the importance of the structural position of a firm in a cooperative network of IT companies. This study also characterizes clusters in a network of IT companies. Most of these clusters comprise a combination of IT companies in diverse IT industries. These clusters suggest that these companies engage in multilateral cooperation without boundaries to maximize their business capabilities. This study offers practical implications for establishing a cooperative strategy and framework that can capture business trends in the IT industry from a macroscopic view. This study also visualizes collaborative networks in a multifaceted way using social network analysis to provide researchers and business practitioners with an informative viewpoint.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.6
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• pp.597-611
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• 2009

With the advent of ubiquitous computing society, many advanced technologies have enabled wireless sensor networks which consist of small sensor nodes. However, the sensor nodes have limited computing resources such as small size memory, low battery life, short transmission range, and low computational capabilities. Thus, decreasing energy consumption is one of the most significant issues in wireless sensor networks. In addition, numerous applications for wireless sensor networks are recently spreading to various fields (health-care, surveillance, location tracking, unmanned monitoring, nuclear reactor control, crop harvesting control, u-city, building automation etc.). For many of them, supporting security functionalities is an indispensable feature. Especially in case wireless sensor networks should provide a sufficient variety of security functions, sensor nodes are required to have more powerful performance and more energy demanding features. In other words, simultaneously providing security features and saving energy faces a trade-off problem. This paper presents a novel energy-efficient security architecture in an IEEE 802.15.4-based wireless sensor network called the Hybrid Adaptive Security (HAS) framework in order to resolve the trade off issue between security and energy. Moreover, we present a performance analysis based on the experimental results and a real implementation model in order to verify the proposed approach.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.177-181
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• 2013

As smart devices and OS with communication capabilities based latest NFC (Near Field Communication) have been spreaded, many applications with using existing RFID are being replaced to NFC. Smart NFC technology and existing services and devices can be easily combined convergence and advantage of smart phones, such as authentication and billing, medical care, the creation of a new paradigm of Network Communication are to be expected. By developing H/W, S/W of the Smart NFC Security Authenticator(SNSA), satisfying with wireless communication test results within accepted reference value, analyzing and testing the impact of topology, the signal performance of Daisy Chain Topology was much better than Star Topology's.

• Journal of Information Technology Applications and Management
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• v.22 no.3
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• pp.115-128
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• 2015

Although the telecommunications service industry has become a basic infrastructure component of the information and communication technology (ICT) industry, it is now losing its reputation as a cash cow due to achieving a saturation of service subscribers, especially in South Korea. With the exception of improving network speeds, network operators are experiencing difficulties in creating new innovations. Therefore, new innovations for the telecommunications service industry should be identified in conjunction with government policies for industry promotion. To examine the innovative capabilities of a specific industry, innovation system theories were used as a framework for research. However, existing innovation systems are limited with regard to explaining the openness of relationships and user participation which are general properties of the ICT industry. Moreover, as sources of innovative activity, additional values such as financial support and collaboration are more appropriate. This study presents a new innovation system based on innovation values. We analyze the telecommunications service industry and prioritize the importance of telecommunication policies within South Korea. An in-depth interview with experts based on the innovation system framework is conducted first. Next, innovation factors derived from the interview are applied within an analytic hierarchy process (AHP), leading to a prioritization of innovation factors for the telecommunications service industry.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.2
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• pp.24-30
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• 2014

In this paper, a new remote terminal unit(hereafter RTU) is proposed to manage a wide range of applications and a variety of sensors (eg, pressure, water quality, temperature and humidity sensors, the amount of pollutants, $CO_2$, etc.) to monitor and control the facility such as water treatment plant, intake and effluent pumping station, water tank and distribution network. Fault status of local sensor devices and network are alerted by using the embedded fault handling capabilities of the RTU in the system and also sent to the fault handling server, by which fault can be easily monitored to users. The developed system was applied to one of K-water branch offices in Geoje city and improved its reliability and stability for controlling and monitoring water facility.

• Journal of KIISE:Software and Applications
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• v.31 no.9
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• pp.1150-1160
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• 2004

In this paper, we propose a new 3D video coding method for heterogeneous display systems and network infrastructure over enhanced Access Grid (e-AG) using spatio-temporal scalability defined in MPEG-2. The proposed encoder produces several bit-streams for providing temporally and spatially scalable 3D video service. The generated bit-streams can be nelivered with proper spatio-temporal resolution according to network bandwidths and processing speeds, visualization capabilities of client systems. The functionality of proposed spatio-temporal scalability can be exploited for construction of highly scalable 3D video service in heterogeneous distributed environments.

• Korean Management Science Review
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• v.29 no.1
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• pp.153-168
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• 2012

Order allocation is one of the most important decision-making problems of firms having significant influences on performances of themselves and the whole supply chain. Existing researches about order allocation have mainly focused on evaluating capabilities of directly connected suppliers so that it is hard to consider effects and interactions from undirected connections over multiple lower-layers. To alleviate the limitation, this paper proposed a novel approach to order allocation using structural hole. By applying the concept of structural hole to the supply network, we could evaluate the structural supplying powers of firms with respect to both of direct and indirect connections. In the proposed approach, we derived a methodology to measure the potential supplying power of each firm by modifying the effective size as one of the measurements of structural hole and then, proposed its application, the structural hole based order allocation strategy. Furthermore, we conducted the agent based modeling of supply chain to perform the decision-making process of order allocation and simulated the proposed strategy. As a results, by coping with the variance of demand more stably, it could improve the performance of supply chain from the aspects of fill rate, inventory level and demand-supply balance.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.10
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• pp.761-765
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• 2009

This research aims an optimal placement of Mobile Base Station (MBS) under HAP based network configurations with the restrictions of HAP capabilities. With clustering algorithm based on BIRCH, mobile ground nodes are clustered and the centroid of the clusters will be the location of MBS. The hierarchical structure of BIRCH enables mobile node management by CF tree and the restrictions of maximum nodes per MBS and maximum radio coverage are accomplished by splitting and merging clusters. Mobility models based on Jeju island are used for simulations and such restrictions are met with proper placement of MBS.

• Korea Multimedia Society
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• v.12 no.4
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• pp.28-40
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• 2008

Vehicular ad hoc networks (VANETs) are a practical application class of wireless ad hoc networks, which consist of moving vehicles equipped with radio communication capabilities that collaborate to form a temporary network. This paper addresses issues and protocols of multihop routing in such emerging networks in the context of safety and infotainment applications. Due to the highly dynamic mobility of vehicles, frequent link breakage and short connection time are inevitable and, thus, the routing is a challenging task and interest for many researchers and industrial community. The frequent and dynamic change of topology makes the topology-based routing unreliable but the position-based routing more effective. The position-based routing consists of the location service which maps a node id to a geo-graphical position and the forwarding scheme which selects the next hop based on geo-graphical information of the node, its neighbors and the destination. The routing techniques are further categorized into geographical forwarding, trajectory forwarding and opportunistic forwarding based on the forwarding scheme. In this paper, we first present the distinguished properties of VANETs and the challenges and intractable issues posed in designing the routing protocols, followed by the comprehensive survey of existing routing protocols. Then, the different routing protocols designed for VANETs are compared in terms of characteristics, performance and application domains.