• Journal of the Korean Data and Information Science Society
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• v.24 no.5
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• pp.1077-1088
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• 2013

High-dimensional data analysis arises from almost all scientific areas, evolving with development of computing skills, and has encouraged penalized estimations that play important roles in statistical learning. For the past years, various penalized estimations have been developed, and the least absolute shrinkage and selection operator (LASSO) proposed by Tibshirani (1996) has shown outstanding ability, earning the first place on the development of penalized estimation. In this paper, we first introduce a number of recent advances in high-dimensional data analysis using the LASSO. The topics include various statistical problems such as variable selection and grouped or structured variable selection under sparse high-dimensional linear regression models. Several unsupervised learning methods including inverse covariance matrix estimation are presented. In addition, we address further studies on new applications which may establish a guideline on how to use the LASSO for statistical challenges of high-dimensional data analysis.

• Journal of the Korean Data and Information Science Society
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• v.25 no.1
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• pp.245-254
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• 2014

The traditional methods of simulating daily precipitation have paid little attention to the inherent dependence structure between the total precipitation amount and the precipitation frequency for a fixed period of time. To address this issue, we propose a new simulation algorithm using copula in order to incorporate the dependence into the traditional methods. The algorithm consists of two parts: First, while reflecting the observed dependence, we generate the total precipitation amount (S) and the frequency (N) during the period of interest; then we simulate the daily precipitation whose aggregation matches the pair of (N; S) generated in the first part. Our result shows that the proposed method substantially improves the traditional methods.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.3
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• pp.273-279
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• 2009

In this paper, we address the problem of detecting incorrect sonar measurements. We use ideas from the inconsistency of information among sonar measurements together with the sound pressure of the wave from the sonar sensor to develop a new method, called the comparison of the sound pressure (CSP), to detect incorrect sonar readings. The inconsistency of information in cells can be a clue that indicates candidates for incorrect measurements, and the sound pressure of the wave from the sonar sensor determines incorrect readings among the candidates. From various experiments, the proposed method is confirmed that it is better than existing method at deciding the state of sonar measurements.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.481-484
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• 2000

In this paper, we describe the design and implementation of IPv6 LAN. The legacy protocol for Internet is IPv4(IP version 4). The ability of IPv4 is not enough for modern real time multimedia communication services. So IPv6(IP version 6) protocol was suggested to resolve the problems of IPv4. We implemented IPv6 LAN using sTLA(sub Top Level Aggregation identifier) address and KOREN(KOrea Research and Experimental Network). Our IPv6 LAN is connected with 6TAP(Chicago), WIDE(Tokyo), and SingAREN(Singapore). We used a dedicated router, Windows 2000 PC host FreeBSD PC host, Solaris 7 workstation and Solaris 8 workstation for IPv6 NDP(Neighbor Discovery Protocol) protocol test. To support all data services including voice and video, IP protocol should be enhanced because the characteristics of modern network services are requiring QoS(Quality of Service) functions, auto-configuration, security, mobility and so on. So a new IP protocol, IPv6, has been developing to meet the requirements. In this paper, we introduce the implementation method and configuration information of IPv6 LAN.

• Proceedings of the Korea Association of Information Systems Conference
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• 2000.05a
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• pp.171-175
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• 2000

The firewall is normally an intermediate system between the secure internal networks and the less secure external networks. It is intended to keep corporate systems safe from intruders, hackers, and accidental entry into the corporate system. The primary types of firewalls are screening routers, proxy servers, and stateful inspectors. Encryption is another form of firewall protection which is being incorporated along with other firewall methods. Before choosing a firewall architecture, a company must have the right mind set about the threat. The future will see more integration of firewall technologies and the increased use of standards in the industry. It must also determine what are the possible consequences of a breach in security and then develop a system to counter the threat. Additionally, new firewall technologies will address the potential dangers associated with the use of Java applets and Active X-controls on the Internet.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.3
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• pp.15-21
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• 2000

The Intelligent Manufacturing Systems (IMS) Rapid Product Development (RPD) Project is an international partnership formed to build a pre-competitive research and development program that will address the integration of new technologies in manufacturing and provide an infrastructure for industry to cooperate much more closely in the product development cycle. In this explanatory paper, a research trend of the RPD project is briefly presented, together with its background and state-of-the-art, focusing on objectives and target results of its sub-projects which include rapid development of functional parts and tools, validation and reverse engineering, and information logistic system.

• Asia pacific journal of information systems
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• v.25 no.3
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• pp.423-444
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• 2015

Ideation is a process of generating new ideas or solutions using online crowd-sourcing technologies. This process has the potential to change the ways by which government agencies innovate and solve problems. Although increasingly more government agencies are implementing online ideation programs to tap into their employees' ideas and creativity, little is known about the unique challenges and effective practices of such programs. Thus, many government agencies are undergoing trial and error and often reinventing the wheel. This research aims to address this problem. By analyzing a focus group session and four cases of U.S. federal government ideation programs designed for their employees, this research identifies important organizational and technological challenges and effective practices. Furthermore, effective practices are grouped into different phases of ideation process and strategic vs. tactical levels to provide more meaningful and actionable insights. This research is an important step towards building a theoretical foundation for government ideation programs. The implications and limitations of this study are discussed.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06b
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• pp.216-220
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• 2008

본 논문에서는 도로명과 건물 번호에 기초한 새주소 체계를 우편 물류 환경에 도입하므로 발생되는 문제점과 영향 요소를 기술하며 각각의 영향 요소에 대한 구체적인 대응을 모색한다. 새주소 체계는 우편물의 접수 및 구분 및 배달 과정에서 모두 영향을 주며 현재의 정보 시스템이나 우편물 구분 장치에도 직.간접을 영향을 주어 단기적으로는 새로운 주소 체계를 관리하는 우편 주소 관리 시스템 도입이 요구되고, 아울러 기존의 지번 주소와 새주소의 매칭 테이블 구축 및 집배구 수작업 구분 환경 개선 등이 요구되며, 중.장기적으로는 새주소 DB 구축을 통한 우편물 구분 장치의 새주소 인식 기능 개선 및 새주소 체계에 적하한 우편번호 및 집배구 체계 도입이 필요하다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.3
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• pp.405-416
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• 2013

ZigBee is a wireless sensor network protocol recognized as a next-generation standard infrastructure for WBAN and Smart Grid. Security plays an important role in several ZigBee applications. Especially, strict membership control should be enforced when the membership is changed during the join and leave operations in ZigBee. In this paper, we investigate the security weakness of the current leave operation in ZigBee and propose a new security scheme to address it as well as its security and performance analysis.

• Journal of information and communication convergence engineering
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• v.10 no.1
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• pp.21-26
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• 2012

As the new requirements for wireless sensor networks are emerging, real-time communications is becoming a major research challenge because resource-constrained sensor nodes are not powerful enough to accommodate the complexity of the protocol. In addition, an efficient energy management scheme has naturally been a concern in wireless sensor networks for a long time. However, the existing schemes are limited to meeting one of these two requirements. To address the two factors together, we propose real-time communications with two approaches, a protocol for satisfied conditions and one for unsatisfied. Under the satisfied requirement, existing real-time protocol is employed. On the other hand, for the unsatisfied requirement, the newly developed scheme replaces the existing scheme by adjusting the transmission range of some surplus nodes. By expanding the transmission range, the end-to-end delay is shortened because the number of intermediate nodes decreases. These nodes conserve their energy for real-time communications by avoiding other activities such as sensing, forwarding, and computing. Finally, simulation results are given to demonstrate the feasibility of the proposed scheme in high traffic environments.