• Journal of Sensor Science and Technology
• /
• v.10 no.4
• /
• pp.250-258
• /
• 2001

In this study, a lightning warning system (LWS) which can predict a lightning return stroke is developed, and the LWS is based on the measurement of electric field intensity at the ground level. The LWS consist of a rotation-type field mill as an electric field sensor, an impedance changer, a two-stage amplifier, and a microprocessor unit. From the calibration experiment, the frequency bandwidth and the maximum resolution of the LWS are $DC{\sim}200\;[Hz]$ and 73 [V/m], respectively. Also, the LWS can measure the electric field strength caused by a thunderstorm up to 18.7 [kV/m] at the ground. To ensure the sensing ability of the developed LWS in an actual situation, computer simulation using thundercloud models was carried out, and the result showed that the LWS can monitor the movement of thunderclouds within 6 [km] from the observation site.

• Journal of the Korean Magnetics Society
• /
• v.6 no.3
• /
• pp.158-164
• /
• 1996

The magnetic and magneto-optical properties of the Tb/Co multilayers as a function of the layer thickness and the ratio of Tb/Co thicknesses were studied. When the thickness of Tb layer was $12{\AA}$, the maximum perpendicular anisotropy energy and the maximum thickness ratio which displays the perpendicular anisotropy were obtained. This result indicated that the Tb-Tb and Co-Co pairs as well as the Tb-Co pairs contribute to the perpendicular anisotropy. The Kerr rotation angle, $({\theta}_k)$ was proportional to the perpendicular anisotropy energy and was inversely proportional to the average spin dispersion angle, $(\alpha)$. The maximum $({\theta}_k)$ of $0.28^{\circ}$ was obtained in the film of $12{\AA}$ Tb and the thickness ratio of 1.55. The abnormal hysteresis loops were appeared during the aging treatment because the coercivity difference between the Co layer and the Tb layer was increased by the preferential oxidation of Tb.

• Cartoon and Animation Studies
• /
• s.15
• /
• pp.237-249
• /
• 2009

Interest in and study on 3 dimensional pictures has been continued since visual media showing moving images was invented. From simple anaglyph wearing glasses to hologram making perfect 3 dimensional objects by recording phase data of reflected light, as well as amplitude and wave, speed and scope of technical development are quicker and wider, respectively. However, despite such development of technology, there is still lack of study on aesthetical, industrial and contents developing area, except for technology of 3 dimensional images. Unlike the interest in 3 dimensional images, even a theoretical frame for the approach to theoretical areas of 3 dimensional images has not been established. Especially, few experiment and study on directing aesthetics have been conducted, with exception of areas in entertainment documentaries for 3 dimensional feeling or some latest 3D animations. As a result, this study will try to find alternatives to directing aesthetics of realistic 3 dimensional movies to be developed in future by studying directing grammar and aesthetics of digital 3 dimensional movies and finding and analyzing difference between 3 dimensional images and 2 dimensional images drawn on the plane.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 2009.11a
• /
• pp.127-130
• /
• 2009

국가 간 문화의 차이에 의하여 생활습관이나 방식이 많이 다르게 나타난다. 그 중에서도 음식은 다른 분야보다 많은 차이를 나타난다. 특히 음식의 종류에 따라 사용되는 음식도구 중 디자인요소가 동일하고 유사한 것이 있거나 다른 요소와 기능을 갖는 경우도 있다. 따라서 각 국가 간의 음식도구를 유니버설 하게 사용할 수 있는 도구 디자인 연구가 필요하다. 본 연구의 목적은 음식에 대한 행동분석프로세스를 개발하여 국가 간 음식문화의 차이에서 오는 공통점과 차이점을 찾아내어 공용으로 사용할 수 있는 음식도구의 디자인요소를 창의성의 관점에서 제안하기 위한 연구이다. 본 연구의 연구방법과 내용으로는 첫째, 음식에 대한 소비자행동 분석 프로세스의 개발 및 관찰을 통하여 행동분석에 대한 이론적 고찰과 현장에서 일어나고 있는 행동분석을 접목하여 음식행동분석프로세스를 개발하였다. 둘째로, 개발된 프로세스를 이용하여 국가 간 음식의 주문부터 평가까지의 과정을 비교 분석하고 나타난 현상에 대한 문제점 파악 및 이에 대한 결과물을 각 국가별 학생들을 대상으로 음식도구에 대한 디자인 개발을 진행하였다. 셋째, 국가별 개발된 디자인 안을 대상으로 선호도, 요인분석, 상관분석을 통하여 국가별 선호요소와 창의성평가요소의 상관관계를 알아보았다. 본 연구를 통하여 얻어지는 효과는 개발된 프로세스를 이용하여 국가별, 음식별, 행동별, 식당형태별로 비교분석이 가능하도록 하게 하고 얻어진 결과를 이용하여 구체적으로 음식도구 디자인에 이용할 수 있으며 국가간 동일 아이템을 디자인 교육시간에 진행시켜 대학의 디자인교육의 비교를 통하여 상호간에 협력과 상호보완으로 새로운 아이디어를 공유, 아이디어 전개에 도움이 될 수 있다.

• Journal of KIISE:Software and Applications
• /
• v.27 no.5
• /
• pp.463-472
• /
• 2000

In this paper, we consider the problem of realizing associative memories via cellular neural network(CNN). After introducing qualitative properties of the CNN model, we formulate the synthesis of CNN that can store given binary vectors with optimal performance as a constrained optimization problem. Next, we observe that this problem's constraints can be transformed into simple inequalities involving linear matrix inequalities(LMIs). Finally, we reformulate the synthesis problem as a generalized eigenvalue problem(GEVP), which can be efficiently solved by recently developed interior point methods. Proposed method can be applied to both space varying template CNNs and space-invariant template CNNs. The validity of the proposed approach is illustrated by design examples.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.3
• /
• pp.240-248
• /
• 2016

As a new technical approach, the achievement of an eco-environmental leisure boat with a photovoltaic system is attempted by simultaneously actuating nine photovoltaic solar panels, in association with an applied sail control system by use of wind. In this approach, the photovoltaic system consists of a solar module, an inverter, a battery, and relevant components, while the sail control device is equipped with a sail up/down and mast-turning instrument. Furthermore, this research conducts a performance evaluation of the manufactured prototype and acquires the purposed quantity value and the development purpose items. The significant items-sail up/down speed (seconds) and mast turning angle (degrees)-are evaluated during the performance test. In the process of the performance evaluation, a wind direction sensitivity of 90% and a maximum instant charging power of 900 W were also obtained. In addition, the maximum sail time is evaluated in order to acquire the optimum quantity.

• Journal of The Korean Association For Science Education
• /
• v.36 no.1
• /
• pp.159-166
• /
• 2016

This study analyzed perceptions and difficulties in applying Flipped Learning with an interview method grounded on understanding and experience of Flipped Learning in science class. The interviewees selected were six teachers working in Seoul and Gyeonggi Province. Three teachers having over two years of experience in operating Flipped Learning in science were selected, one each from elementary, middle, and high school and another three teachers who had just started to operate Flipped Learning this year were chosen, one each from elementary, middle, and high school. According to the result of a 3-step interview conducted with the participating teachers, they indicated very high satisfaction with the implementation of Flipped Learning in elementary, middle, and high school science classes. They responded that Flipped Learning was particularly more helpful for inquiry activity. The teachers, however, felt burdened by the class preparation and had difficulty in organizing the class. To explore ways to get rid of the difficulties in Flipped Learning, this author discussed the textbook system where one could draw various implications for improving the current class.

• Polymer(Korea)
• /
• v.39 no.3
• /
• pp.468-474
• /
• 2015

Electrically conductive polymer nanocomposites were prepared by the inclusion of graphene-based nanofillers. Graphene oxide (GO) and reduced graphene oxide wrapped by poly(styrene sulfonate) (PSS-RGO) were used as nanofillers to make good dispersion with the aqueous dispersion of polystyrene (PS) particles. GO sheets were synthesized by the modified Hummers' method from graphite, and PSS-RGO sheets were prepared by the reduction of GO-dispersed PSS solution with hydrazine monohydrate. Morphology and properties of PS/GO and PS/PSS-RGO nanocomposites via latex technology were investigated. Both nanofillers showed well dispersed morphology in PS matrix. Rheological and electrical percolation thresholds were 0.28 and 0.51 wt% for GO, and 0.50 and 1.01 wt% for PSS-RGO respectively. It is speculated that PS/GO nanocomposites showed better conductivity than PS/PSS-RGO counterparts due to the partial recovery of GO by thermal reduction during molding.

• Journal of Korea Multimedia Society
• /
• v.15 no.1
• /
• pp.93-100
• /
• 2012

Recently, the security monitoring and control systems based on spatial information in various field are operated and being developed according to evolve the spatial information technology. Especially, the CCTV monitoring and control system can be used in various field as a typical system. However, the security vulnerability problems have become an issue because the system connected by computer network and getting bigger than before. Therefore we studied security vulnerabilities of CCTV monitoring and control system which is being developed and operated. In addition, it is important to consider disaster and terrorism with unauthorized changes on location information. Therefore we analyzed the performance of observation when the cameras are break down as a result by hacking to CCTV monitoring and control system.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.408-408
• /
• 2012

반세기가 지나는 동안 우리는 반도체의 크기가 계속해서 작아지는 것을 경험해왔다. 반도체 디바이스들의 차원이 100 nm 이하로 작아지면서, 나노와이어나 나노튜브로 이루어진 나노 소자들은 필연적으로 양자효과[1] 같은 저차원효과가 나타나게 된다. 특히 1차원 반도체 구조에서는 전자상태 밀도의 변화에 수반되는 전자-포논의 상호작용이 감소되어 전자이동도가 증가할 것으로 예측되었고, 이러한 이동도의 증가는 그동안 나노와이어나 나노튜브의 전기 전도도 증가가 일어난 실험적 데이터를 설명하는 이론적 받침이 되었다[2]. 한편 일차원 반도체 구조 체에서는 채널의 저차원화에 따른 전기장의 불균일성이 심화되고 이로 인하여 벌크와 매우 다른 전기수송 특성이 나타날 수 있는데 이러한 점이 그동안 간과되어 왔다. 본 연구에서는 시뮬레이션을 통하여 양자효과를 배제한 정전기적인 저차원 효과만으로도 전기 전도도가 증가할 수 있음을 보이고자 한다. 우리는 푸아송 방정식과 표동-확산 방정식을 SILVACO사의 ATLAS 3D 시뮬레이터를 이용하여 풀었다. 이 시뮬레이션에 사용된 실리콘 나노와이어는 길이를 $2{\mu}m$로 고정시키고 다양한 정사각형 단면적을 가진 구조로 하였다. 여기서 정사각형의 한변을 10nm 에서 100 nm까지 변화시켰다. 실리콘 채널의 도핑농도가 $1{{\times}}1016cm-3$일 경우, 낮은 전압, 즉 < 0.5 V 이하 영역에서는 벌크와 같은 선형적인 전류-전압 특성이 나타나지만, 그 이상의 전압 영역에서는 전류-전압 그래프가 위로 휘어지며(super-linear) 전기전도도가 확연히 증가함을 알 수 있었다. 예를 들어 2 V에서는 벌크에 비하여 흐르는 전류가 2배나 더 향상되었다. 이런 비선형적인 성질은 높은 전압을 인가하였을 때 나노와이어 채널 전반에 걸쳐 charge neutrality가 깨지게 되고 전하밀도가 증가하여 전도도 증가가 일어나는 것으로 밝혀졌다. 이 결과는 기존의 나노선에서의 전기전도도 증가 현상을 설명할 수 있는 대안을 제공할 수 있다.