Ilyong Yoon Byoungho Lee Soojin Park 《Photonics Technology Letters, IEEE》2006,18(6):776-778

A new fiber depolarizer employing a polarization beam splitter loop structure is proposed and demonstrated. The depolarizer is devised for broad-band operation and the depolarization of narrow linewidth light source without any help of polarization controllers or Faraday rotator mirrors. A polarizing method is developed that shows good performance without polarization control unit. Therefore, the proposed depolarizer can be cost-effective and easily configured. From experiments, low output degree of polarization less than 10% is obtained for a narrow linewidth light source.  相似文献   

    

Young‐Keun Yoon  Heon‐Jin Hong  Ik‐Guen Choi 《ETRI Journal》2007,29(2):234-236

Interference effects of ultra‐wideband devices using the frequency band from 3.1 to 10.6 GHz on wireless broadband are evaluated. The ultra‐wideband emission power spectral density that would be necessary to protect a wireless broadband station is considered. Also, an analytic scheme based on a system level simulation of a WiBro system is proposed.  相似文献   

    

Jang‐Uk Shin  Su Hwan Oh  Yoon‐Jung Park  Sang‐Ho Park  Young‐Tak Han  Heekyung Sung  Kwang Ryong Oh 《ETRI Journal》2007,29(4):452-456

Very compact 4‐channel 200‐GHz‐spacing external cavity lasers (ECLs) were fabricated by hybrid integration of reflection gratings and superluminescent laser diodes on a planar lightwave circuit chip. The fifth‐order gratings as reflection gratings were formed using a conventional contact‐mask photo‐lithography process to achieve low‐cost fabrication. The lasing wavelength of the fabricated ECLs matched the ITU grid with an accuracy of ×0.1 nm, and optical powers were more than 0.4 mW at the injection current of 80 mA for all channels. The ECLs showed single mode operations with more than 30 dB side lobe suppression.  相似文献   

    

Jangwoon Park  Yoon Chang  Wongi Hong  Myungeun Lee  Ahreum Han  Youngjoo Chae  Gilsoo Cho  Heecheon You 《人机工程学与制造业中的人性因素》2014,24(3):318-327

In parallel to the social trend of green consumerism and well‐being, the demand for naturally colored organic cotton (NaCOC) continually increases in the textile and clothing industry. The present study examined the effects of NaCOC color, scouring method, and age on the visual sensibility of NaCOC. Two age groups (20s and 30s; 40s and 50s) of women rated three color sets of NaCOC specimens (ivory, green, and coyote brown) treated by two chemical scouring methods (Na₂CO₃ and NaOH) and two bioscouring methods (enzyme and boiling water) using 7‐point scales of nine visual sensibilities (bright‐dark; clear‐murky; heavy‐light; vivid‐subdued; warm‐cool; fresh‐stale; strong‐weak; showy‐plain; and luxurious‐cheap). Preferred scouring methods by NaCOC color and/or age group were recommended for each visual sensibility (e.g., preferred scouring methods for fresh sensibility are Na₂CO₃ for ivory NaCOC, Na₂CO₃ and NaOH for green NaCOC, and boiling water for coyote brown NaCOC). In addition, the representative visual sensibilities of each NaCOC color (e.g., those of coyote brown NaCOC are dark, murky, heavy, vivid, warm, stale, strong, plain, and luxurious sensibilities) were identified for the women participants. Last, it was demonstrated that a bioscouring method can replace the traditional chemical methods for selected visual sensibilities (e.g., boiling water for luxurious sensibility). © 2012 Wiley Periodicals, Inc.  相似文献   

    

Dong Hwan Kim  Ji‐Yoon Kang  Kyo‐Il Lee 《野外机器人技术杂志》2000,17(10):527-547

The focus of this work is on a robust tracking control design for a 6 DOF parallel manipulator in the presence of nonlinearity and fast (or slowly) time‐varying uncertainty. Two types of controllers are presented. The controls are based on the Lyapunov approach and guarantee a practical stability. The controls utilize the information of link displacements and its velocities. The first control scheme uses the quadratic Lyapunov function and other uses the geometry dependent Lyapunov function, which excludes the inverse matrix computation on the inertia matrix. Also, the hydraulic dynamics is considered in the control design and control performance. The control performances of the proposed algorithms are verified by simulations and experiments. © 2000 John Wiley & Sons, Inc.  相似文献   

    

S. Kim  M. Yoon  †  S.-M. Whang  ‡  B. Tversky§  & J.B. Morrison¶ 《Journal of Computer Assisted Learning》2007,23(3):260-270

Abstract  Although animations are believed to be effective in learning and teaching, several studies have failed to confirm this. Nevertheless, animations might be more attractive and motivating. Fourth and sixth grade students learned the operation of a bicycle pump from graphics that were: (i) presented simultaneously; (ii) presented successively; (iii) self-paced, or (iv) animated. The presentation mode affected evaluation of perceived comprehensibility, interestingness, enjoyment and motivation, but not comprehension test score. Fourth graders who were low in need for cognition rated the animations as more enjoyable and motivating, whereas sixth graders rated self-paced graphics as more interesting and motivating. The evaluations of sixth graders correspond to results of many studies on learning. Animations are not more effective than equivalent static graphics in learning, and they are not seen as more motivating by sixth graders.  相似文献   

    

Yoon Chang  Jussi Kantola  Hannu Vanharanta 《人机工程学与制造业中的人性因素》2007,17(6):511-520

The aim of this research was to study the nature of creative tension of engineering students in South Korea. The creative tension was analyzed according to relevant competences in project managers' work role. Most of the subjects who participated in this study were part‐time students who worked as managers in manufacturing and industrial companies. The application used for collecting and analyzing data was the project managers' work‐role–based competence application, Cycloid. Data were collected on the Internet by self‐evaluation. The constructed competence model of the Cycloid application was added into the Evolute self‐evaluation system utilizing fuzzy logic. The application was able to identify students' current state and personal aims and the creative tension essential for their personal development. The Cycloid application can be utilized in developing the professional competencies of individuals, teams, and organizations. © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 511–520, 2007.  相似文献   

    

Jeong‐Doo Yi  Joon‐Yeon Kim  Tae‐Woo Kim  Hak‐Cheol Yang  Jeong‐Nam Kim  Yoon‐Hyoung Cho 《Journal of the Society for Information Display》2005,13(11):883-888

Abstract— We propose a PDP having a new structure and driving scheme. An auxiliary electrode was inserted between X and Y electrodes. Driving and discharge stability was determined using a test panel. A 42‐in. SD (852 × 480) panel and a 42‐in. HD (1366 × 768) panel were also made having this new structure, and we verified the increase in luminous efficacy and the reduction of ionic losses. We achieved a luminous efficacy of 2.35 lm/W in an SD panel and 1.97 lm/W in a HD panel. Finally, we investigated the characteristics and merits of the new structure.  相似文献   

    

Min Soo Kim  Sin‐Hye Park  Seon‐Young Han  Yun‐Ho Kim  Eun‐Jung Lee  Jung Han Yoon Park  Young‐Hee Kang 《Molecular nutrition & food research》2014,58(4):698-708

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Joo Dong Park  Jae W. Park  Won B. Yoon 《Journal of texture studies》2013,44(3):247-252

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