• Journal of the Institute of Electronics Engineers of Korea CI
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• v.39 no.4
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• pp.10-18
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• 2002

Network topology design is a multiobjective problem with various design components. The components such as cost, message delay and reliability are important to gain the best performance. Recently, Genetic Algorithms(GAs) have been widely used as an optimization method for real-world problems such as combinatorial optimization, network topology design, and so on. This paper proposed a method of Multi-objective GA for Design of the network topology which is to minimize connection cost and message delay time. A common difficulty in multiobjective optimization is the existence of an objective conflict. We used the prufer number and cluster string for encoding, parato elimination method and niche-formation method for the fitness sharing method, and reformation elitism for the prevention of pre-convergence. From the simulation, the proposed method shows that the better candidates of network architecture can be found.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.9
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• pp.2967-2981
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• 2014

Device-to-Device (D2D) communication is a technology component for long-term evolution-advanced (LTE-A). In D2D communication, users in close proximity to each other can communicate directly without going through a base station; such direct communication can improve spectral efficiency. Although D2D communication brings improvement in spectral efficiency, it also causes interference to the cellular network as a result of spectrum sharing. In particularly, D2D communication can generate interference for each D2D pair when the common wireless medium in a co-located limited area is accessed. Even though the interference management for between the D2D pair and cellular networks has been proposed, the interference reducing methods have still not been fully studied for the D2D pairs. In this paper, we investigate the problem of D2D pair coexistence in which interference is considered between D2D pairs. Using a signal to interference model for a target D2D pair, we provide an analysis of the aggregated throughput of a dense D2D network. For a target D2D pair, we assume that the desired signal and interference signals obey multipath fading and shadow fading. Through analysis, we demonstrate the effect of cluster size such as the number of D2D pairs and the size of the considered area on the network performance. The analytical results are compared with computer simulations. Our work can be used for a rough guideline for controlling the system throughput in a dense D2D network environment.

• KNOM Review
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• v.22 no.3
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• pp.20-24
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• 2019

Blockchain is a distributed ledger-based technology where all nodes participating in the blockchain network are connected to the P2P network. When a transaction is created in the blockchain network, the transaction is propagated and validated by the blockchain nodes. The verified transaction is sent to peers connected to each node through P2P network, and the peers keep the transaction in the memory pool. Due to the nature of P2P networks, the number and type of transactions delivered by a blockchain node is different for each node. As a result, all nodes do not have the same memory pool. Research is needed to solve problems such as attack detection. In this paper, we analyze transactions in the memory pool before solving problems such as transaction fee manipulation, double payment problem, and DDos attack detection. Therefore, this study collects transactions stored in each node memory pool of Bitcoin and Ethereum, a cryptocurrency system based on blockchain technology, and analyzes how much common transactions they have using jacquard similarity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.5
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• pp.907-915
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• 2003

A very efficient packet transmission scheme is needed in the radio environment where radio resource is insufficient as compared with the environment of the wired communication. In general, dual mode packet transmission scheme is used broadly. Packets are transmitted through the dedicated or common chamois according to a switching criterion. The general criteria are the length and generation frequency of packet, that is, large and frequent packets are transmitted using a dedicated channel and small and infrequent packets are transmitted using a common channel. The performance of dual mode packet transmission scheme is closely related to the switching criteria. However, it is very difficult to find the optimal switching point because that is not fixed but variable according to the environment such as traffic load, length of generated packets, and the number of channels. In this paper, a new scheme for the dual mode packet transmission scheme using a dynamic switching threshold is proposed where the switching threshold is not fixed but variable according to the network environment. The performance of the proposed method is analyzed using a simulation. From the simulation results, it is shown that the performance of the proposed scheme is not very influenced by the network environment unlike the conventional dual mode packet transmission scheme.

• Korea journal of population studies
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• v.31 no.3
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• pp.107-130
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• 2008

The study of Korean diaspora has focused on migration, adaptation, and identity of overseas Koreans in China, the CIS, Japan, and the United States. However, the contemporary concept of a diaspora is a way of understanding migration, cultural difference, identity politics, and so on. Thus, this more broadly defined diaspora is used to mean a dispersion of people of a common national origin or of common beliefs living in exile. As of 2007, it is estimated that there are about 7 million Koreans living in 170 countries outside the Korean peninsula. Some have left Korea involuntarily and some others voluntarily. But most of them actively try to maintain their identity and culture as Koreans. With the large number of overseas Koreans, there has recently been the recognition of the importance of networking among overseas Koreans in the 21st century. The purpose of this paper is to emphasize the necessity of Korean Global Network of overseas Koreans. In doing so, this paper reviewed the case of Jewish and Chinese network. Then, this paper indicates the problems in the networking of overseas Koreans and suggests the policy implications for Korean Global Network. Above all, there should be changes in the government's policy towards overseas Koreans in the direction of organizing networks of overseas Koreans to coexist with the mother country. The government should adopt a policy to restore trust in overseas Koreans. It should take a pragmatic approach to the mutual interests in the socioeconomic relations instead of taking a political approach to overseas Koreans.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7B
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• pp.1261-1267
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• 1999

Frame relay (FR) service via an FR interface over a common asynchronous transfer mode (ATM) backbone network requires an FR-to-ATM interworking unit (IWU), the functionality of which directly impacts the engineering of the overall network in terms of capacity required, quality of service (QoS), and the interference among different types of services. This paper presents performance analysis of frame relay traffic in IWU. Additionally frame relay traffic policing using leaky bucket algorithm in this traffic model is carried out through computer simulation. Three measurements, the percentage of frames accepted as committed, the percentage of frames that accepted but marked eligible for diacard, and the percentage of frames that accepted that are discarded because of insufficient number of credits, are simulated variously in this paper.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.5
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• pp.1967-1983
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• 2020

The goal of this paper is to analyze and build an algorithm to recognize hand gestures applying to smart home applications. The proposed algorithm uses image processing techniques combing with artificial neural network (ANN) approaches to help users interact with computers by common gestures. We use five types of gestures, namely those for Stop, Forward, Backward, Turn Left, and Turn Right. Users will control devices through a camera connected to computers. The algorithm will analyze gestures and take actions to perform appropriate action according to users requests via their gestures. The results show that the average accuracy of proposal algorithm is 92.6 percent for images and more than 91 percent for video, which both satisfy performance requirements for real-world application, specifically for smart home services. The processing time is approximately 0.098 second with 10 frames/sec datasets. However, accuracy rate still depends on the number of training images (video) and their resolution.

• STI Policy Review
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• v.5 no.1
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• pp.57-74
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• 2014

This review organises the fragmented management literature on platform business according to a conceptual map and a meta-theoretical scheme. Since the early 2000s, numerous researchers have examined platform business and two-sided networks with platform business and strategy being an important business innovation model for many industries, creating value primarily by enabling direct interactions. Platforms such as Google or Amazon contain a common set of rules and components in most user transactions. Thirty-two core papers and books on Strategic Management Journal, Industrial Economics and Operation Management-related disciplines are reviewed, with further observations on how cumulative research streams on the platform are carried out independently from each academic perspective. The first of the two arguments in this paper is that because interactive relationships bridge the platform and stakeholders such as end-users and developers, it is crucial for platform companies to be aware of their relationship with stakeholders in order to support and sustainably provide content to their platform. The second is that integrative perspectives are essential due to the low number of interdisciplinary investigations conducted thus far. The paper's final section deals with implications for theory and practice, concluding that integrative studies and interactive relationship studies should be the main research streams in future platform research.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.667-672
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• 2009

Gathering information and systemization of infrastructure disaster management is to reduce uncertainties in making decisions and maximize the number of alternations. The key objects of a sensor-based progress report and propagation automation systems are to provide objective data, realize and support decision making and deliver them to a certain area, department, manager and other people rapidly. The major findings and results of this study are as follows. 1) Application of international standard-based alerting protocol(CAP; Common Alerting Protocol). 2) Development of database of existing progress report and propagation manual in order to achieve networking of safety management on major social infrastructure of the nation. 3) Development middleware application programs to progress report and propagation data using SMS, FAX, EMS, VMS, MMS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10B
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• pp.876-884
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• 2008

In this paper, we propose an asynchronous MAC protocol to minimize energy usage and to maximize data throughput for a wireless sensor network in multi channel environments. Our proposed SPMC-MAC (Slim Preamble Multi-Channel Media Access Control) adopts the preamble sliming mechanism proposed in [6] that takes advantage of the knowledge about the wakeup time of the receiver node. The preamble contains the receiver's ID and a randomly selected channel ID for data communication, and it is transmitted over a dedicated common channel. The power control has the benefit of keeping an appropriate number of nodes with the communication range, resulting in reduced collision and interference. We compare our SPMC-MAC and X-MAC extensively in terms of energy consumption and throughput using mathematical analysis and simulation.