• Journal of Digital Contents Society
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• v.19 no.8
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• pp.1545-1554
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• 2018

In order to support the mobility of the wireless devices, at least two APs (Access Points) must be arranged in a single AP area to maintain communication area. In the WLAN (Wireless LAN) environment, seamless handover is one of the most important issues in terms of effective utilization of wireless networks and maximization of services for users. On the other hand, SDN (Software-Defined Networking), which is emerging rapidly in recent years, is revolutionizing network management in terms of flexibility, fine control, and convenience. SDN originally reduces latency time or increases network robustness by real-time flow table control reducing or bypassing paths between switches in LAN-based data centers. In this study, we apply OpenFlow, a SDN platform focused on wired LAN, to a dense WLAN environment using legacy APs to implement and evaluate seamless handover for streaming services of digital contents.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.2
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• pp.19-29
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• 2004

In this paper, the beam steering dipole phased array antenna systems for IMT-2000 base station have been designed. The designed beam steering dipole phased array antenna systems are constituted by the antenna part and the beam steering control system part. The antenna part is designed by the proposed flat dipole for the broadband characteristics, and the 8${\times}$8 dipole way antenna is constructed by the Proposed flat dipole for the directional radiation pattern. Besides the vertical Power divider is designed for the vertical power distribution. The beam steering control system part is designed the horizontal power divider for the horizontal power distribution, the 4-bit phase shifters and the driving circuit of phase shifters for the horizontal beam tilting. In order to evaluate a performance of the designed antenna systems, they were fabricated and the radiation characteristics were measured. From the measured results, we found that the horizontal beams were tilted by the each control signals, and the measured radiation characteristics showed good agreement with the design goals.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.1019-1034
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• 2022

Malware attacks become more prevalent in the hyper-connected society of the 4th industrial revolution. To respond to such malware, automation of malware detection using artificial intelligence technology is attracting attention as a new alternative. However, using artificial intelligence without collateral for its reliability poses greater risks and side effects. The EU and the United States are seeking ways to secure the reliability of artificial intelligence, and the government announced a reliable strategy for realizing artificial intelligence in 2021. The government's AI reliability has five attributes: Safety, Explainability, Transparency, Robustness and Fairness. We develop four elements of safety, explainable, transparent, and fairness, excluding robustness in the malware detection model. In particular, we demonstrated stable generalization performance, which is model accuracy, through the verification of external agencies, and developed focusing on explainability including transparency. The artificial intelligence model, of which learning is determined by changing data, requires life cycle management. As a result, demand for the MLops framework is increasing, which integrates data, model development, and service operations. EXE-executable malware and documented malware response services become data collector as well as service operation at the same time, and connect with data pipelines which obtain information for labeling and purification through external APIs. We have facilitated other security service associations or infrastructure scaling using cloud SaaS and standard APIs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.2
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• pp.343-350
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• 2010

In the existing design of web server architecture, data encryption technique is used to keep the reliability, stability, and safety of web service. But the use of data encryption technique wastes the work of cpu while decreasing throughput of web server and increasing average response time so that it shows negative effect on the capacity of web application server. Also, the latest web applications require security and safety for the safe internet communication. Therefore, this paper suggests the improved web server which uses thread pool and Non-blocking I/O adding new web service modules to the existing web server for the safe web service, provides reliability and safety to show the safe web service capacity. And we compare and evaluate the safety and capacity through experiment on the existing traditional Tomcat based web server and the proposed system to evaluate the safety and capacity of the proposed web server system.

• Korean Journal of Legislative Studies
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• v.25 no.2
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• pp.141-177
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• 2019

This paper explains cross-national variation of CPI(corruption perception index) centering on legal culture. By critically reviewing previous researches on effects of British common law system on corruption, we define legal culture as citizens' perception of their legal system. Specifically, measuring legal culture with respect to courts fairness and courts accessibility, we test two hypotheses on effects of legal culture on corruption. A cross-national comparison of 78 countries with OLS regression analyses reveals that courts fairness tends to lower the level of corruption while courts accessibility does not have a significant effect on corruption. Based on this result, we suggest policy implications for judicial reform as well as anti-corruption measure, which puts more emphasis on reforming legal practice that hinders courts fairness than increasing legal service supply. In addition, as the essence of legal culture lies in citizens' shared perception of the legal system, we argue that a broad and solid citizens' consciousness of fair and equitable legal procedures is indispensable in preventing corruption.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.3
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• pp.895-905
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• 2018

Public opinion polls have a strong influence on modern society as a means of examining the tendency of social groups on specific issues. As the influence of the polls increases, the problem of forgery and falsification of the results becomes an important issue. So, to guarantee the reliability of the results, our society needs novel mechanisms. As one of such mechanisms, the Ethereum blockchain is an environment for developing decentralized applications with the reliable blockchain technology. Ethereum decentralized applications can utilize smart contracts to provide services for users in transparent and reliable ways. In this paper, we propose a polling method that guarantees reliability using the blockchain technology, which is a distributed ledger technique that makes forgery or falsification actually impossible. The proposed method provides a robust verification function on the results of the associated polls for individual voters and verification organizations. Also, we present a distributed opinion polling application running on our private Ethereum blockchain network, showing the effectiveness of the proposed method.

• Journal of Convergence for Information Technology
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• v.12 no.4
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• pp.270-277
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• 2022

Today, due to the serviceization of the economy, volume and position Global trade in Services have gradually increased. Stable and fair trade can be achieved through solid international trade law. Multilateral discussions on service trade agreement have been stagnant, but have recently shown considerable outcome. Service trade agreement(GATS) deal with various service trade barriers in member countries that hinder free trade in services. Recently, a group of WTO members have established the 「Joint Initiative on Services Domestic Regulation」. The agreement aims to ensure that licensing and qualification requirements and procedures, as well as technical standards do not constitute unnecessary barriers to services trade. This study is to understand the type and statistics of service trade barriers that affect actual service transactions. At the same time, It aims to examine the progress of discussions on multilateral service trade agreement for resolving service trade barriers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.206-215
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• 2007

Ad-Hoc network technology is a mobile internet technology of the future that will be used widely not only in Mobile Network but also in Wireless Personal Area Network (WPAN) and Ubiquitous Network For this to occur, distributed routing protocol design, loop prevention for link information reduction in overhead for control messages and route restoration algorithm must be improved or complemented. Security techniques that can guarantee safe com-munication between Ad-Hot nodes net also be provided. This study proposes and evaluates a new authentication mechanism for MANET. The mechanism segregates the roles of certification authority to keep with the dynamic mobility of nodes and handle rapid and random topological changes with minimal over-head. That is, this model is characterized by its high expandability that allows the network to perform authentication service without the influence of joining and leaving nodes. The efficiency and security of this concept was evaluated through simulation.

• Journal of IKEEE
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• v.5 no.1 s.8
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• pp.100-110
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• 2001

In this paper, we investigated several buffer management schemes for the design of shared-memory type ATM switches, which can enhance the utilization of switch resources and can support quality-of-service (QoS) functionalities. Our results show that dynamic threshold (DT) scheme demonstrate a moderate degree of robustness close to pushout(PO) scheme, which is known to be impractical in the perspective of hardware implementation, under various traffic conditions such as traffic loads, burstyness of incoming traffic, and load non-uniformity across output ports. Next, we considered buffer management strategies to support QoS functions, which utilize parameter values obtained via connection admission control (CAC) procedures to set tile threshold values. Through simulations, we showed that the buffer management schemes adopted behave well in the sense that they can protect regulated traffic from unregulated cell traffic in allocating buffer space. In particular, it was observed that dynamic partitioning is superior in terms of QoS support than virtual partitioning.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.886-888
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• 2005

고품질의 확장성 있는 서비스를 제공함으로써 다수의 사용자의 요청을 처리하고 시스템을 견고하게 유지할 수 있는 인터넷 서버를 구현하기 위한 한 가지 방법은 비동기 입출력 기능(AIO)을 이용하는 것이다. 기존의 고전적인 입출력 방식인 poll()/select()에 비해 AIO는 CPU 부하를 비롯한 시스템 자원의 낭비를 줄일 수 있으며, 입출력 완료를 기다리면서 블록되지 않으므로 시스템 부하를 감소할 수 있다. 본 논문에서는 리눅스 커널에 구현되어 있는 파일 기반 AIO기능을 네트워크 소켓 상에서 동작할 수 있도록 확장 구현하였으며, 그 구조에 대하여 자세히 설명하였다. 또한 클라이언트-서버 구조를 모델링한 실험을 통해 기존 메커니즘과의 성능 차이를 비교하였다.