• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.121-122
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• 2002

중금속은 산업화 이후 오늘날까지 개발도상국뿐만 아니라 선진국에서도 지속적인 모니터링을 하며 관리하고 있는 환경오염물질이다. 납(Pb)과 카드뮴(Cd)은 산업화된 도시의 대기, 수질 및 토양의 모든 환경 매체에 분포하고 있는 환경오염물질이다(Lopez-Artiguez et al., 1993; Buchet et al., 1983). 특히, 환경중의 카드뮴 노출은 생물학적 반감기가 길기 때문에 특별히 더 중요한 의미를 가지는 잘 알려진 유독성의 물질이며(Buchet et al., 1983; Muller and Anke, 1994; Ikeda et al., 1989, 1995), 장기간의 직업상의 노출과 환경노출에 기인하는 독성의 영향도 최근 연구되어지고 있다(Jarup et al., 1998). (중략)

• Information and Communications Magazine
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• v.23 no.5
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• pp.114-126
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• 2006

본 논문에서는 USN 임베디드 시스템을 활용한 재난재해 방지 서비스의 설계 및 실증 시험내용을 기술한다. '하르방' 프로젝트로 명명된 본 연구에서는 최근 활발하게 연구되고 있는 USN 기술을 한라산 국립공원의 등산로에 적용함으로써, 고정밀의 기상 정보를 실시간으로 제공하고 재난재해 상황 감시 및 상황 발생을 실시간으로 알려 조기에 상황 대응이 가능하도록 하였다. 현재 독자적으로 연구개발이 이루어지고 있는 BcN, IPv6, USN 기술을 하나로 융합한 차세대 유비쿼터스 네트워크의 구조 연구는 향후 관련산업을 선도함은 물로, 실제 응용에서도 범국가적인 정밀하고 광범위한 기상예보와 재난재해 방지 시스템으로서의 역할을 수행할 것으로 예상된다.

• The tire
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• s.86
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• pp.29-36
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• 1980

'77년 10월에 미일양국의 고무과학자 약 50명은 고무의 도시 미국의 Akron대학 고분자학과 연구소에서 「고무상 탄성체에 관한 미일 세미나」를 개최하였다. 그 때 특수강연으로서 노벨 과학자인 Flory 교수의 "고무 탄성론의 진보" 외에 D.McIntyre교수(Akron대학)의 "Guayule고무의 분자구조", E, Compos Lopez 박사(멕시코 국립응용화학연구소소장)의 "Guayule고무의 응용"의 두 강연이 있었다. 그 후 새로운 고무 연구에 관해서는 일본학술진흥회와 멕시코의 과학기술회의간에 과학자교류협정까지 이루어지고, Guayule고무에 대한 연구가 많이 진행되고 있다. 또 미국화학회 고무부회에서도 Guayule고무의 성질에 관한 연구발표회가 있는 등 미국에서도 관심 뿐만 아니라, 이미 연구과정이 많이 진보되고 있는 중이다. 그리고 일본에서도 최근 많은 총설이 발표되었으므로 아울러 참조하고자 한다.<편집자주>

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.205-210
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• 2004

The interaction of disk galaxies with intergalactic winds has been invoked as a possible mechanism of the generation of galactic warps. Here we discuss conditions under which intergalactic flows can be relevant for warping field galaxies. Constraints include the heating of the outer disk, the level of asymmetry in the vertical distribution of the volume gas density, the angular frequency of the warp, the symmetry of galactic warps amplitude between the approaching and receding sides of the galaxy, and the speed of the intergalactic flow whether subsonic or supersonic. These constraints are discussed in this paper in reference to the proposal of Lopez-Corredoira et al. that warps can be a natural consequence of accretion flows onto the disk.

• Journal of Convergence Society for SMB
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• v.4 no.3
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• pp.21-25
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• 2014

Group communications are becoming popular in Internet applications such as video conferences, on-line chatting programs, games, and gambling. Secure and efficient group communication is needed for message integration, confidentiality, and system usability. However, the conventional group key agreement protocols are too much focused on minimizing the computational overhead by concentrating on generating the common group key efficiently for secure communication. As a result, the common group key is generated efficiently but a failure in authentication allows adversaries to obtain valuable information during the group communication. After achieving the secure group communication, the secure group communication should generate the group key efficiently and distribute it to group members securely, so the balance of security and system usage must be considered at the same time. Therefore, this research proposes the software architecture model of a secure and efficient group communication that will be imbedded into networking applications.

• ETRI Journal
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• v.33 no.3
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• pp.393-400
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• 2011

A systematic approach for the design of two-stage class AB CMOS unity-gain buffers is proposed. It is based on the inclusion of a class AB operation to class A Miller amplifier topologies in unity-gain negative feedback by a simple technique that does not modify quiescent currents, supply requirements, noise performance, or static power. Three design examples are fabricated in a 0.5 ${\mu}m$ CMOS process. Measurement results show slew rate improvement factors of approximately 100 for the class AB buffers versus their class A counterparts for the same quiescent power consumption (< 200 ${\mu}W$).

• ETRI Journal
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• v.32 no.1
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• pp.157-159
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• 2010

Tree-based routing Ethernet (TRE) is a recent Ethernet architecture that enables shortcut links to improve performance compared to spanning tree protocols. However, TRE can only use shortcuts that arrive directly at bridges located in the branch of the destination. TRE+ extends the topology knowledge of a bridge to 2 hops away, thus unveiling new shortcuts to the destination branch. Simulations show a major performance improvement of TRE+ compared to TRE, with results close to shortest paths in some topologies.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.72.3-72.3
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• 2016

A massive envelope and a strong bipolar outflow are the two most distinct structures of youngest protostellar systems. We present observational results from the Combined Array for Research in Millimeter-wave Astronomy (CARMA) toward the youngest (Class 0) protostellar system L1157. At an angular resolution of 5 arcseconds, we mapped its well-developed outflow in CO 2-1 over a span of approximately 5 arcminutes. Additionally, we imaged the central envelope with CO isotopes, CS, CN, and N2H+ with an angular resolution of about 2 arcseconds. We show that the bipolar outflow may be represented with a two jet model and constrain its physical properties such as precession/rotation directions, velocities, inclinations, and position angles via cube data fitting. In addition, we discuss the kinematic features of the envelope detected in CO isotopes and N2H+ and present the radius-dependent dust opacity spectral index.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.304-306
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• 2016

In the recent years ransomware has become one of the most popular malware used by criminals. This particular type of malware is notorious for locking users' data or systems and unscrambling it only after the victims pay a fee. With more and more individuals, companies and public agencies being targeted and the ransom being as high as $17,000, the need for countermeasures against this kind of malware is greater than ever. This paper explores how the malware infects and encrypts its victims. Then, it suggests mitigation techniques based on how the ransomware spreads, making special emphasis on countermeasures in order to protect end-users.

• ETRI Journal
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• v.30 no.4
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• pp.535-545
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• 2008

This paper introduces a systematic top-down and bottom-up design methodology to assist the designer in the implementation of continuous-time (CT) cascade sigma-delta (${\Sigma}{\Delta}$) modulators. The salient features of this methodology are (a) flexible behavioral modeling for optimum accuracy-efficiency trade-offs at different stages of the top-down synthesis process, (b) direct synthesis in the continuous-time domain for minimum circuit complexity and sensitivity, (c) mixed knowledge-based and optimization-based architectural exploration and specification transmission for enhanced circuit performance, and (d) use of Pareto-optimal fronts of building blocks to reduce re-design iterations. The applicability of this methodology will be illustrated via the design of a 12-bit 20 MHz CT ${\Sigma}{\Delta}$ modulator in a 1.2 V 130 nm CMOS technology.