• Smart Structures and Systems
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• 제20권2호
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• pp.151-162
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• 2017

In practical engineering, the friction damper is a widely used energy dissipation device because of its large deformation capacity, stable energy dissipation capability, and cost effectiveness. While based on conventional friction dampers, the double-sliding friction damper (DSFD) being proposed is different in that it features two sliding friction forces, i.e., small and large sliding friction forces, rather than a single-sliding friction force of ordinary friction dampers. The DSFD starts to deform when the force sustained exceeds the small-sliding friction force, and stops deforming when the deformation reaches a certain value. If the force sustained exceeds the large sliding friction force, it continues to deform. Such a double-sliding behavior is expected to endow structures equipped with the DSFD better performance in both small and large earthquakes. The configuration and working mechanism of the DSFD is described and analyzed. Quasi-static loading tests and finite element analyses were conducted to investigate its hysteretic behavior. Finally, time history analysis of the single-degree-of-freedom (SDOF) and multi-degree-of-freedom (MDOF) systems were performed to investigate the seismic performance of DSFD-equipped structures. For the purpose of comparison, tests on systems equipped with conventional friction dampers were also performed. The proposed DSFD can be realized perfectly, and the DSFD-equipped structures provide better performances than those equipped with conventional friction dampers in terms of interstory drift and floor acceleration. In particular, for the MDOF system, the DSFD helps the structural system to have a uniform distributed interstory drift.

• Asian Pacific Journal of Cancer Prevention
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• 제16권15호
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• pp.6561-6568
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• 2015

Background: Smokeless tobacco (SLT) has long been realized as an important component of the fight for global tobacco control. It still remains a major problem in countries like India, Bangladesh and Nepal. The objective of this study was to estimate the trends of SLT use in three countries of the SEARO WHO office. Materials and Methods: We used data from national surveys in three countries (Bangladesh, India and Nepal) to estimate trends in prevalence of current SLT use. All available nationally representative data sources were used. Estimates were weighted, age standardized and given along with 95% confidence intervals. Significance of linear trend in prevalence over time was tested using the Cochrane-Armitage test for trend. A p value of less than 0.05 was considered statistically significant. Results: We identified three surveys for Bangladesh, three for India and four for Nepal that met the selection criteria (such as Demographic and Health Surveys, WHO-STEPwise approach to Surveillance and Global Adult Tobacco Surveys). A significantly increasing trend was noticed in the prevalence of current SLT use among Bangladeshi men (20.2% to 23%, p=0.03). In India, a similar significantly increasing trend was seen among men (27.1% to 33.4%, p<0.001) and women (10.1% to 15.7%, p<0.001). In Nepal, there was a no significant trend among both men (39.1% to 31.6%, p=0.11) and women (5.6% to 4.7%, p=0.49). Conclusions: In the study countries SLT use has remained at alarmingly high levels. Usage trends do not show any signs of decline in spite of control efforts. Tobacco control measures should focus more on controlling SLT use.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.191-194
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• 1995

This paper evaluates the influences of sex on the human emotions while coexisting with robots. When we consider human vision, robot's motion is the most important parameter which influences human emotions and must be well controlled for males and females emotions. On the other hand, when we consider human touch of sense, which is effective for cooperation transmitting mutual forces, the softness of robot is an important parameter for human emotions and must be also well controlled for males and females emotions. From these points of view, at first, we evaluate robot's motion under four different shapes of velocity pattern while handing over a cup to humans. Second, we evaluate robot's softness realized by impedance control. From the first experiment, we concluded that the conditions of choosing an adequate maximum velocity value and locating the velocity peak at the center or the first half of the duration are necessary for male's emotions. In addition, the smooth velocity decrease in the last part of the velocity pattern's duration is desired for female's emotions. From the second experiment, we concluded that females prefer lighter values of virtual impedance characteristics than males and any small increase on the heaviness of virtual impedance values is followed by the negative exponential change on human emotions.

• 한국환경복원기술학회지
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• 제16권1호
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• pp.245-257
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• 2013

Lately, besides promoting the biodiversity of the natural ecosystems, there is a demand for climate change mitigation features that will reduce greenhouse gases and prevent disasters that will bring damages such as torrential rains. However, there was not a lot of discussion on the soils that are key in these features. Therefore, this paper proposes a network (Gold Network) as an alternative that will solve the problem that was filed earlier by figuring out how to compose the soil environment. First, in order to maximize the ecological status and value of the soil, a soil network can be proposed through the vertical and horizontal connections of the fragmented soil. Second, there is a need to understand and research the organic system of the ecosystems as well as the complex perspective of the ecosystem services, not only the fragmentary perspectives of the soil remediation, planting improvements or the other existing elements. Third, there is a need to apply the integrated perspective of the Landscape Ecology, Ecological Engineering and Restoration Ecology for the connectivity of the soil (network) due to it being in the execution of the soil network. If a soil network was to be built, a fundamental ecological network would be realized to not only promote biodiversity but also to prepare effective adaptation to climate change.

• 전자공학회논문지D
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• 제34D권3호
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• pp.60-73
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• 1997

By introducing a compressive-strained quanternary InGaAsP quantum-wells instead of a conventional ternary InGaAs quantum-wells in 1.55.mu.m DFB-LD, the lasing performances canb e improved and the problems caused by the thickness non-uniformity and the compositional abruptness among the hetero-interpaces canb e relaxed. In this paper, we investigated an iptimum InGaAsP/InGaAsP multiple-quantum-well(MQW) structure as an active layer in a direct-modulated 1.55.mu. DFB-LD from the view point of threshold current, chirping charcteristics, and resonance frequency. The optimum compressive-strained MQW structure was revealed as InGaAsP/InGaAsP structure with strain amount of about 1.2%, number of wells $N_{w}$ of 7, well width $L_{w}$ of 58.agns.. The threshold current density J of 500A/c $m^{2}$, the linewidth enhancement factor a of 1.8, and differential resonance frequency of d $f_{r}$/d(I-I)$^{1}$2/=2GHz/(mA)$^{1}$2/(atI=2 $I_{th}$) were expected in 1.55.mu.m .gamma./4-shifted DFB-LD with the cavity length of 400.mu.m long and kL value of 1.25. These values are considerably improved ones compared to those of 1.55um DFB-LD with InGaAs/InGaAsP MQW which have enhancement factor and the resonance frequence frequency by the detuning of lasing wavelength and gain-peak wavelength. It was found that the linewidth enhancement factor of 20% and differential resonance frequency of 35% without the degradation of the threshold current density could be enhanced in the range of -15nm~-20nm detuning which can be realized by controlling the thickness and Incomposition of InGaAsP well. well.and Incomposition of InGaAsP well. well.

• 한국콘텐츠학회논문지
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• 제5권5호
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• pp.287-295
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• 2005

본 논문에서는 유비쿼터스 컴퓨팅 기술의 여러 응용 서비스에서 가장 핵심적인 요소 기술 중의 하나인 사용자의 상황인식시스템에 대하여 기술한다. 제안하는 시스템은 실험 대상자의 우측 상완에 착용하는 $SenseWear(R)PRO_2R$ Armband (BodyMedia사)에 내장된 2차원 가속도센서를 이용하여, 센서에서 출력되는 가속도 변화량의 절대치의 평균치인 MAD(mean of absolute difference)를 계산하여 활동량을 정량화 하였으며, PC 기반의 눕기, 앉기, 걷기, 뛰기 4단계 동작의 인체동작상태 구분과 한정된 응급상활을 인지하는 퍼지추론 시스템으로 구현하였다. 본 시스템으로 측정한 수직방향의 MAD는 눕기, 앉기, 걷기, 뛰기에서 각각 0.204 g/s, 0.373 g/s, 2.808 g/s, 16.243 g/s이었다. 이들을 이용하여 분석한 인체동작 인식률은 눕기, 앉기, 걷기 뛰기에 대하여 각각 96.7 %, 93.0 %, 95.2 %, 98.4 %로 나타났으며, 제한된 상황에서의 응급상황인식률은 100 %이었다.

• 복식문화연구
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• 제15권1호
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• pp.152-168
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• 2007

The aim of this study is to shed light on essentials of Suprematist artists focusing on Malevich and their works in relation to modem design, and to examine their roles in the modem design industry compared to those of modem designers. The study obtains the following result on Suprematist artists and their works in Russian avant-garde in terms of modem design. Firstly, Suprematist artists had a great deal of interest in practical design although it seemed Suprematist were replaced by utilitarianism in avant-garde during the Russian revolution. Secondly, Suprematist artists were the first artists to bring the birth of modem design trends by applying their art in geometric forms to clothing and fabric design as well as ornaments and handicraft. Thirdly, the artists' attempt to work with needle workers made it possible to set achievements in design and modem decorative art exhibitions in various fields of art-life. As for the role of modem designers, Suprematist artists including Malevich have significant meanings as follows: Firstly, Malevich was a creative, future-oriented artistic designer who realized zaum of painting on the stage and created suprematistic mode in a cosmic point of view in order to agree with the environment. Secondly, Suprematist artists knew the importance of works that were produced by craftsmen and worked together with them. Therefore, the designers could maintain fabric decoration in difficult conditions knowing the importance of the high value-added industry. Thirdly, they were artists in real life who embodied the ideas and theories of Suprematist in sample works by recognizing the need of changes in life environment: they planned to set a new visual world in art but did not confine the idea only to painting.

• 한국정보통신학회논문지
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• 제19권10호
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• pp.2269-2274
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• 2015

본 논문은 S 형태의 folded 커플링(coupling) 구조를 이용하여 세로 측의 크기를 줄인 λg/4 단락형 협대역 스터브(stub) 대역통과 여파기에 대해 제안을 한다. 제안된 여파기는 스터브의 구현을 위해 스터브의 임피던스 값 변화 없이 스터브의 위치를 변화시켜, 그에 따른 Qe(External Quality Factor) 값을 이용하여 협대역 대역통과 여파기를 구현 한다. 또한 협대역 대역통과 여파기의 전송선로 부분에 S 형태의 커플링(coupling) 구조를 집적시켜, 여파기의 가로 측 크기를 줄이도록 한다. 제안된 여파기의 중심 주파수는 5.8GHz, 대역폭은 3.4 % 이며, 삽입손실 및 반사손실은 각각 1.46 dB 및 16.5 dB의 측정결과를 얻었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.471.2-471.2
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• 2014

We demonstrate here that an improvement in precursor film density (green density) leads to a great enhancement in the photovoltaic performance of CuInSe2 (CISe) thin film solar cells fabricated with Cu-In nanoparticle precursor films via chemical solution deposition. A cold-isostatic pressing (CIP) technique was applied to uniformly compress the precursor film over the entire surface (measuring 3~4 cm2) and was found to increase its relative density (particle packing density) by ca. 20%, which resulted in an appreciable improvement in the microstructural features of the sintered CISe film in terms of lower porosity, reduced grain boundaries, and a more uniform surface morphology. The low-bandgap (Eg=1.0 eV) CISe PV devices with the CIP-treated film exhibited greatly enhanced open-circuit voltage (VOC, from 0.265 V to 0.413 V) and fill factor (FF, from 0.34 to 0.55), as compared to the control devices. As a consequence, an almost 3-fold increase in the average power conversion efficiency, 3.0 to 8.2% (with the highest value of 9.02%), was realized without an anti-reflection coating. A diode analysis revealed that the enhanced VOC and FF were essentially attributed to the reduced reverse saturation current density (j0) and diode ideality factor (n). This is associated with the suppressed recombination, likely due to the reduction in recombination sites such as grain/air surfaces (pores), inter-granular interfaces, and defective CISe/CdS junctions in the CIP-treated device. From the temperature dependences of VOC, it was confirmed that the CIP-treated devices suffer less from interface recombination.

• 한국정보통신학회논문지
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• 제21권10호
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• pp.1943-1949
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• 2017

최근 메이커 문화는 스스로 '만들다'라는 개념을 하이테크놀로지 최신 기술을 통해 실현시키고 있다. 개인의 제작 방법 및 정보를 인터넷을 통해 서로 공유함으로서 메이커 운동으로 빠르게 확산되고 있다. 메이커 운동을 선도하는 국가들은 메이커 운동을 사물인터넷 관점에서 새로운 가치 창조 및 경제 성장의 동력이 될 것이라고 전망하고 있다. DIY (Do It Yourself)를 통해 제작하고 개발된 다양한 사물인터넷 디바이스와 서비스를 등록하고, 상호 연동하여 서비스를 실현할 수 있는 다양한 형태의 개방형 IoT (Internet of Things) 플랫폼을 개발하고 있다. 일반적인 개방형 IoT 플랫폼들은 전문적인 API (Application Programming Interface) 분석 능력이 필요하며, 까다로운 플랫폼 등록조건과 절차로 인해 일반 사용자들의 접근이 어려운 실정이다. 본 논문에서는 일반 메이커 사용자의 관점에서 보다 간편한 구조의 사물인터넷 디바이스와 서비스 애플리케이션을 제작하고, 실제 서비스로 구동 할 수 있는 개방형 IoT 플랫폼을 구성하고자 한다.