• Title/Summary/Keyword: Sound Power

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The Relationships among High School Students' Conceptual Understanding of Molecular Structure and Cognitive Variables (분자 구조에 대한 고등학생들의 개념 이해도와 인지 변인의 관계)

  • Noh, Tae-Hee;Seo, In-Ho;Cha, Jeong-Ho;Kim, Chang-Min;Kang, Suk-Jin
    • Journal of The Korean Association For Science Education
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    • v.21 no.3
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    • pp.497-505
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    • 2001
  • In this study, the relationships among students' conceptual understanding of molecular structure and cognitive variables were investigated for 165 high school students. After they had learned 'High School Chemistry II' for two semesters, the tests of conception concerning molecular structure, spatial visualization ability, logical thinking ability, mental capacity, and learning approach were administered. The results indicated that students' conceptual understanding of molecular structure was not sound, and several misconceptions were found. The scores of the conception test were significantly correlated with all the cognitive variables studied. Multiple regression analyses were conducted to examine the predictive influences of students' cognitive variables on their conceptual understanding. Meaningful learning approach was the most significant predictor and were followed by logical thinking ability, rote learning approach, and mental capacity. However, spatial visualization ability did not have the predictive power.

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The Interdisciplinary Research on Cultural Technology (문화기술에 관한 간학제적 연구 -미디어아트를 통한 혼합현실형 공공 문화콘텐츠를 중심으로-)

  • Lim, Kyung-Ho;Yoon, Joon-Sung
    • 한국HCI학회:학술대회논문집
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    • 2009.02a
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    • pp.1359-1362
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    • 2009
  • Digital media technology has power of influence as extended in not only science and technology but also our society and culture. These phenomenon is explained as 'digital convergence'. Edmond Couchot argue the term 'hybridization'. Yvonne Spielmann and Jay David Bolter also argue that digital hybrid artworks across and integrates a diverse range of modes of representation, such as image, text, sound, space and bodily modes of expression. They must also address communicative interaction in the convergence of real and virtual spaces. In this paper, I noticed mixed reality environment which is seen as the form of hybrid between real and virtual object. And I discuss about this phenomenon as the study of interdisciplinary between art and science.

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A sensor controller for map building of home service robot using low cost PSD sensor (저가형 PSD센서를 이용한 홈서비스 로봇의 Map building용 센서 제어시스템)

  • Hyun, Wong-Keun;Lee, Chang-Hwan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.10
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    • pp.1897-1904
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    • 2006
  • Home service robot must recognize and build map for indoor and components of the house such as furniture and chair etc. The previous researcher has developed a indoor map building system by using CCD camera and ultra sonic sensor. %no stems have some problem in such a way that (1) a distun resolution can be changed according to the number of pixel when we use a CCD camera system, (2) a measured distance can be decreased when it transmitted to the rubber because of being absorbed the sound energy. This paper represents an intelligent sensor controller of module has been developed by using optic PSD(Position Sensitive Detector) sensor any at a low price. To deduce the switching noise from beam power module and diffused reflection noise, we proposed a heuristic soft filter. The performance of the developed system was compared with ultra sonic sensor system by detecting the indoor wall environment. Some experiments were illustrated for the validity of the developed system.

A Study on the Fashion Sensibilities of Korean Clubbers (한국 클러버(Clubber)의 패션 스타일 연구)

  • Kim, Ji-Lyang;Choy, Hyon-Sook
    • Journal of the Korean Society of Costume
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    • v.58 no.4
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    • pp.155-170
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    • 2008
  • Club culture is the global trend for youth in 21st century. Club is the space that is created with close relationship among music, dance and fashion. It is also experimental cultural art space with endlessly transforming style. Furthermore it is a space for independent minor culture which represents speciality than generality of cultural appetite and style of club. Cultural communities formed around club and their parties have placed as a strong subculture trend based on youth age group. What they are creating as a subculture could be our tomorrow's main trend and clubbers also could be our major power sources for future. Therefore it is necessary to pay attention to club culture. The purposes of this research are to identify the concept of clubber, to analyzes their basic club culture characteristics and elements, and to find out unique fashion styles of Korean clubber in comparison with the origin. To study club fashion style's origin and background, this study searched a theoretical flow from 1930's to 1990's. Then, Korean clubber's style is derived by comparing background and origin of Korean club culture with those of abroad. To analyze in various point of view, theoretical backgrounds about social, cultural, dresses, and design were considered. Since research target is a visual image, street fashion is analyzed on through, music channels and magazines from 1930's to present as well as designer's art photographies. Internet sites', cub culture association's and sound association's photos were also extracted. as a visual evidences to offer actual evidences. Geological targets are selected among Korean club culture's origin such as Hong-Ik University area, Shin-chon, Chungdam-dong and Apgujung-dong areas. The results of this study are as follows. Firstly, clubber's fashion style influenced magnificently on major fashion design instead of being just youngster's resistance toward control group and it is contributing to our fashion culture to enrich it. Secondly, fashion styles of korean clubbers are based on those of western sub-culture, but with a unique localized history.

A Study on the Detection Range of Acoustic Instruments for Fisheries (수산음향계측장치의 탐지범위에 대한 연구)

  • Park, Ju-Sam
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.41 no.1
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    • pp.54-63
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    • 2005
  • Detection ranges of acoustic instruments mainly used for fisheries and their research are derived as the range bordered by a certain signal-to-noise ration (SNR) thershold. The SNR is depicted by several factors on transmitting and receiving, sound propagation, scattering by objects, and mainly self-ship noise. The detection ranges are shown for several fisheries instrument, such as echo sounder, quantiative echo sounder, and bio-telemetry system. The results can be used for designing the instruments, examining the capability of user's own instruments, and interpreting obtained data or echograms. Increasing transmitting power is not as effective for high frequencies as for low frequencies to increase the detection range. Comparison of volume backscattering strengths obtained by the quantitative echo sounder at several frequencies should be done within the same detection range. By applying the concept of the detection range for the bio-telemetry receiver beams, the number of the beams and the beamwidths can be determined.

Development and Evaluation of Real-time Acoustic Detection System of Harmful Red-tide Using Ultrasonic Sound (초음파를 이용한 유해적조의 실시간 음향탐지 시스템 개발 및 평가)

  • Kang, Donhyug;Lim, Seonho;Lee, Hyungbeen;Doh, Jaewon;Lee, Youn-Ho;Choi, Jee Woong
    • Ocean and Polar Research
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    • v.35 no.1
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    • pp.15-26
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    • 2013
  • The toxic, Harmful Algal Blooms (HABs) caused by the Cochlodinium polykrikoides have a serious impact on the coastal waters of Korea. In this study, the acoustic detection system was developed for rapid HABs detection, based on the acoustic backscattering properties of the C. polykrikoides. The developed system was mainly composed of a pulser-receiver board, a signal processor board, a control board, a network board, a power board, ultrasonic sensors (3.5 and 5.0 MHz), an environmental sensor, GPS, and a land-based control unit. To evaluate the performance of the system, a trail was done at a laboratory, and two in situ trials were conducted: (1) when there was no red tide, and (2) when there was red tide. In the laboratory evaluation, the system performed well in accordance with the number of C. polykrikoides in the received level. Second, under the condition when there was no red tide in the field, there was a good correlation between the acoustic data and sampling data. Finally, under the condition when there was red tide in the field, the system successfully worked at various densities in accordance with the number of C. polykrikoides, and the results corresponded with the sampling data and monitoring result of NFRDI (National Fisheries Research & Development Institute). From the laboratory and field evaluations, the developed acoustic detection system for early detecting HABs has demonstrated that it could be a significant system to monitor the occurrence of HABs in coastal regions.

Current Status and future of Vermicomposting Industry in Korea (지렁이 퇴비화 운영사례 및 개선방향)

  • Kim, Jong-Oh;Lee, Chang-Ho;Choi, Hun-Gun
    • Journal of the Korea Organic Resources Recycling Association
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    • v.9 no.4
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    • pp.89-98
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    • 2001
  • Present vermicomposting technology needs the broad land. Because of the high land cost, the land saving technology such as multistage must be needed. And present operation practices are mostly based on human power, mechanization and automation is needed. Also, present control practices based on individual experience need the scientific base control system. Even though the rough estimation of organic waste treatment showed that vermicompostiong could obtain more benefits than costs. But, the estimation is based on an ideal case without considering the technical and market. Generally, vermicomposting is considered as the more expensive technology than composting. Therefore, the practical proof the economic factor would be the most important to the market increase. Vermicomposting as the recycling technology has better condition than incineration and landfill. Propagation and advocating focused on its environmentally sound aspects would be needed continuously. Especially, demonstration and distribution of household vermicomposting would be a good approach. Vermicomposting facilities area was becoming larger, and earthworm feeding materials were also expanding to various organic sludges. These trends showed that vermicomposting is being enlightened to treat and recycle the organic wastes.

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A Study on control of weld pool and torch position in GMA welding of steel pipe by using sensing systems (파이프의 가스메탈아크 용접에 있어 센서 시스템을 이용한 용융지 제어 및 용접선 추적에 관한 연구)

  • 배강열;이지형;정수원
    • Journal of Welding and Joining
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    • v.16 no.5
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    • pp.119-133
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    • 1998
  • To implement full automation in pipe welding, it si most important to develop special sensors and their related systems which act like human operator when detecting irregular groove conditions. In this study, an automatic pipe Gas Metal Arc Welding (GMAW) system was proposed to full control pipe welding procedure with intelligent sensor systems. A five-axes manipulator was proposed for welding torch to automatically access to exact welding position when pipe size and welding angle were given. Pool status and torch position were measured by using a weld-pool image monitoring and processing technique in root-pass welding for weld seam tracking and weld pool control. To overcome the intensive arc light, pool image was captured at the instance of short circuit of welding power loop. Captured image was processed to determine weld pool shape. For weld seam tracking, the relative distance of a torch position from the pool center was calculated in the extracted pool shape to move torch just onto the groove center. To control penetration of root pas, gap was calculated in the extracted pool image, and then weld conditions were controlled for obtaining appropriate penetration. welding speed was determined with a fuzzy logic, and welding current and voltage were determined from a data base to correspond to the gap. For automatic fill-pass welding, the function of human operator of real time weld seam control can be substituted by a sensor system. In this study, an arc sensor system was proposed based on a fuzzy control logic. Using the proposed automatic system, root-pass welding of pipe which had gap variation was assured to be appropriately controlled in welding conditions and in torch position by showing sound welding result and good seam tracking capability. Fill-pass welding by the proposed system also showed very successful result by tracking along the offset welding line without any control of human operator.

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A Study on the Costume Play Fashion (코스튬플레이 패션에 대한 연구)

  • 이은영;백천의
    • Journal of the Korea Fashion and Costume Design Association
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    • v.3 no.2
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    • pp.75-86
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    • 2001
  • The article is alms to investigate the characteristics, the originality, and the interest of fashion design of costume play, which is recently specifically popularized among young fashion mania. The influence of commercialization power of the Disneyland and the animation characters of Japanese caricatures makes the costume play to be one of the main new generation culture. Since the costume play just begins at this moment, the full understanding of the costume play is hard because of the small amount of the materials and happenings of the phenomena. However it reveals the design trends and creativity of the new generation. As the investigation of costume play fashion and the types of costume play, the following results are obtained. 1. The originality of the costume play is thought to be induced from the mask which is used against the ghost in primitive ages, the fancy parade of halloween festival, commercial advertisements of Disneyland, the Japanese caricatures, and the animation games. 2. The distinctive characteristics of Korean costume play shows the massive behaviour, which is different from the individualized costume play in Japan. This facts show the parts of the interest culture of the persons who has the equal interest. The costume play is applied as the sound showing culture, in which the young generation express and enjoy themselves by"kki" - the passion of young energy. 3. The boom of costume play introduce the increased number of costume play shop, pro model, and designer. It also introduce the interest of the new fashion design for the young generations. Thus it is expected the new fashion infra structure in near future.ar future.

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Implementation of Ceramic Flat speaker with a D Class Audio Amplifier (D 클래스 오디오 앰프의 세라믹 평판스피커 구현)

  • Yang, Won-Woo;Lee, Sun-Bok;Song, Young-Jun;Lee, Je-Hoon;Hong, You-Sik;Ahn, Jae-Hyeong
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.48 no.6
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    • pp.56-61
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    • 2011
  • A class-D audio amplifier is widely used in coil speaker. This paper presented the technique for applying a class-D audio amplifier to the ceramic flat speaker. This technique can be achieved by employing a matching transmitter in order to replace class-G amplifier that is drven by voltage level to class-D amplifier employing power driving method. Consequently, the presented technique can improve the efficiency by making the voltage driving level a litter larger. We evaluate the sound-level efficiency using the various mediums such as wood, plastic, and paper. From the simulation results, the proposed technique employing a class-D audio amplifier rather than a class-G one showed a 10% improvement. The proposed system can be applicable for the mobile appliances as an external slim speaker.