• 대한수학회지
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• 제44권6호
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• pp.1233-1241
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• 2007

We derive a kind of weighted norm inequalities which relate the commutators of potential type operators to the corresponding maximal operators.

• 대한수학회보
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• 제45권3호
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• pp.477-483
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• 2008

In this paper, by introducing parameter r>1, new weighted Ostrowski-Gruss-Cebysev type inequalities for 1/p+11/q=1-1/r are established.

• Journal of Contemporary Eastern Asia
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• 제18권2호
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• pp.118-141
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• 2019

In South Korea, as awareness of gender equality increased since the 1990s, policies for gender equality and social awareness of equality have been established. Until recently, however, the gap between men and women in social and economic activities has not reached the globally desired level and led to social conflict throughout the country. In this study, we analyze the content of online news comments to understand the public perception of gender equality and the details of gender conflict and to grasp the emergence and diffusion process of emerging issues on gender equality. We collected text data from the online news that included the word 'gender equality' posted from January 2012 to June 2017 and also collected comments on each selected news item. Through text mining and the temporal semantic network analysis, we tracked the changes in discourse on gender equality and conflict. Results revealed that gender conflicts are increasing in the online media, and the focus of conflict is shifting from 'position and role inequality' to 'opportunity inequality'.

• 한국환경보건학회지
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• 제39권4호
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• pp.299-311
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• 2013

Background: Environmental hazards are responsible for as much as a quarter of the total world-wide burden of disease. Therefore, appropriate management of environmental hazards is a critical part of the effort to improve human health. This review aims to summarize current issues, topics, and programs at international institutions such as the World Health Organization (WHO) and the Organization for Economic Cooperation and Development (OECD) in the area of environmental health. Results: The WHO European Center for Environmental Health (ECEH) plays a significant role in implementing environmental health policies and also takes the lead in related issues in Europe. It has developed an Environmental Health Information System and environmental health inequality indicators. In the environmental health area, the OECD focuses most on chemical management programs. It foresees that air pollution and chemical risk management will become the leading environmental health issues if appropriate measures are not taken. Several topics were identified that require greater effort in Korea, including cancer as an environment-related disease, an environmental health information system, and environmental health inequality issues. Conclusions: More active roles are expected from Korea in international societies, in part because of the introduction of the Environmental Health Act of 2008, and active involvement in related activities in WHO WPRO/SEARO. Understanding recent developments and concerns at major international organizations like WHO and the OECD will assist in the implementation of effective international collaboration and the identification of a better strategies for improving environmental health performances in Korea.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권12호
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• pp.3037-3054
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• 2013

Interference between primary user (PU) and secondary user (SU) transceivers should be mitigated in order to implement underlay spectrum sharing in cognitive radio networks (CRN). Considering this scenario, an improved joint subcarrier and bit allocation scheme for cognitive user with primary users' cooperation (PU Coop) in CRN is proposed. In this scheme, the optimization problem is formulated to minimize the average interference power level at the PU receiver via PU Coop, which guarantees a higher primary signal to interference plus noise ratio (SINR) while maintaining the secondary user total rate constraint. The joint optimal scheme is separated into subcarrier allocation and bit assignment in each subcarrier via arith-metric geo-metric (AM-GM) inequality with asymptotical optimization solution. Moreover, the joint subcarrier and bit optimization scheme, which is evaluated by the available SU subcarriers and the allocated bits, is analyzed in the proposed PU Coop model. The performance of cognitive spectral efficiency and the average interference power level are investigated. Numerical analysis indicates that the SU's spectral efficiency increases significantly compared with the PU non-cooperation scenario. Moreover, the interference power level decreases dramatically for the proposed scheme compared with the traditional Hughes-Hartogs bit allocation scheme.

• 한국통신학회논문지
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• 제33권8A호
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• pp.805-814
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• 2008

Both EPCglobal Generation-2 (Gen2) for passive RFID systems and Intelleflex for semi-passive RFID systems use probabilistic slotted ALOHA with Q algorithm, which is a kind of dynamic framed slotted ALOHA (DFSA), as the tag anti-collision algorithm. A better tag anti-collision algorithm can reduce collisions so as to increase the efficiency of tag identification. In this paper, we introduce and analyze the estimation methods of the number of slots and tags for DFSA. To increase the efficiency of tag identification, we propose two new tag anti-collision algorithms, which are Chebyshev's inequality (CHI) algorithm and hybrid Q algorithm, and compare them with the conventional Q algorithm and adaptive adjustable framed Q (AAFQ) algorithm, which is mentioned in Part I. The simulation results show that AAFQ performs the best in Gen2 scenario. However, in Intelleflex scenario the proposed hybrid Q algorithm is the best. That is, hybrid Q provides the minimum identification time, shows the more consistent collision ratio, and maximizes throughput and system efficiency in Intelleflex scenario.

• 전자공학회논문지
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• 제52권12호
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• pp.89-98
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• 2015

본 논문에서는 임의적으로 발생하는 폴리토프 불확실성과 외란을 고려한 시간지연시스템의 강인비약성 $H_{\infty}$ 제어기설계 알고리듬을 다룬다. 먼저 임의적으로 발생하는 불확실성과 외란을 가지는 시간지연시스템을 설계하고, Lyapunov 안정성 분석과 $H_{\infty}$ 성능지수를 기반으로 강인비약성 $H_{\infty}$ 제어기가 존재하기 위한 충분조건을 선형행렬부등식(LMI, linear matrix inequality)의 형태로 제시한다. 구한 충분조건은 변수치환과 슈어 여수(Schur complement) 정리를 바탕으로 파라미터의 함수를 포함한 파라미터화 선형행렬부등식(PLMI, parameterized linear matrix inequality)으로 표현할 수 있으므로 PLMI의 모든 해로부터 제어기이득과 비약성을 만족하는 제어기 섭동영역 및 $H_{\infty}$ 성능을 만족하는 노옴 한계치 ${\gamma}$를 한번에 구할 수 있다. 마지막으로 예제와 모의실험에서 제안한 강인비약성 $H_{\infty}$ 제어기가 임의적으로 발생하는 불확실성 및 외란, 시간지연이 있더라도 폐루프시스템을 안정화시키고 $H_{\infty}$ 성능을 보장함을 확인하고 확정적인 불확실성을 기반으로 설계한 제어기와 성능을 비교한다.

• International Journal of Control, Automation, and Systems
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• 제4권6호
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• pp.682-688
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• 2006

This paper deals with the delay-dependent and rate-independent stabilization of systems with multiple unknown time-varying delays and time-varying structured uncertainties. All the linear matrix inequalities based conditions are derived by employing free-weighting matrices to express the relationships between the terms in the Leibniz-Newton formula. The criteria do not require any tuning parameters. Numerical examples demonstrate the validity of the method.

• International Journal of Control, Automation, and Systems
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• 제5권3호
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• pp.349-354
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• 2007

This paper considers the problem of designing static output feedback controllers for nonlinear systems represented by Takagi-Sugeno (T-S) fuzzy models. Based on linear matrix inequality technique, a new method is developed for designing fuzzy stabilizing controllers via static output feedback. Furthermore, the result is also extended to $H_{\infty}$ control. Examples are given to illustrate the effectiveness of the proposed methods.

• 정보교육학회논문지
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• 제11권4호
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• pp.433-445
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• 2007

정보사회로의 진입과 함께 정보격차는 사회 불평등을 초래하는 새로운 요소로 등장하였다. 특히 학교에서 ICT 활용교육, e-러닝, u-러닝이 점차 확대됨에 따라 학생층에서 나타나는 정보격차는 교육 기회의 불평등으로까지 이어질 우려를 낳고 있다. 이에 따라 학교 구성원들의 정보격차 실태에 대한 관심이 높아지고 있다. 본 연구에서는 학생 및 교사의 정보화 수준과 정보격차 현황을 파악하기 위하여, 경남도내 초중등 학생과 교사를 대상으로 설문조사를 실시하였다. 정보화 수준의 측정은 3개 하위 지수(접근, 역량, 활용)에 대한 가중 평균으로 계산하였다. 조사결과 학생과 교사 집단 모두 역량지수에서 가장 큰 격차를 보였다. 또한 역량지수와 활용지수와의 상관관계를 분석한 결과 두 집단 모두 정적상관을 보여 정보 역량의 차이가 정보격차를 이해하는데 중요한 요인임을 알 수 있었다.