• Title/Summary/Keyword: Time Scales

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Optimal placement of MR dampers for 20-story nonlinear benchmark building (20층 비선형 벤치마크 빌딩에 대한 MR 유체 감쇠기의 최적위치 결정)

  • 장종우;조상원;윤우현;이인원
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.10a
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    • pp.153-160
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    • 2003
  • The objective of optimal placement of dampers for a structure is to maximize the effective-ness of the vibration control with the same number of dampers. While many optimal placement methods of linear viscous dampers have been proposed and used, there are only a few methods for MR dampers. Here some optimal location indices for M dampers are proposed, which are similar to those for linear viscous dampers and show how large the structural responses on each floor are. Every time an additional MR damper is implemented, the optimal location index on each floor is measured, and then the next damper is installed on the floor with the maximum location index. In these sequential procedures, the peak interstory drift, the peak interstory velocity and the absolute acceleration of each floor are selected as the optimal location indeices. Four different earthquakes with various scales are loaded to the 20-story nonlinear benchmark building model (Otori et al. 2000, 2002). Passive On/on algorithms are used in order to represent the control algorithm of M dampers.

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Design Considerations of Auditory Feedback for Enhancing The Usability of Portable Digital Electronic Products (휴대용 디지털 전자제품의 사용성 향상을 위한 청각적 피드백의 고려)

  • Kim, Hyeong-Seok;Park, Min-Yong
    • Journal of the Ergonomics Society of Korea
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    • v.19 no.3
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    • pp.51-60
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    • 2000
  • Non-verbal sound feedback, called earcon, has been used for portable digital electronic products to give appropriate information for the selected function. This study evaluated usability based on user cognition time, error rate, and subjective satisfaction using 20 male and female subjects. The study compared five major user functions from a portable digital electronic product with currently available earcons and the same functions from the product with the new earcons (suggested by this study) which considered user cognitive characteristics, such as loudness, pitch, melody, and length. For subjective evaluation, the study assessed various earcons by subjective impression of sounds using the seven-point rating scales. Major statistical results indicated that the new earcons significantly reduced user error rates and generally improved user performance functions, such as 'play, off, stop, fast forward, and rewind.'

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The Relations of Child Care Quality and Teachers' Participation in Children's Play (어린이집의 질적 수준 및 교사의 놀이참여와 아동의 놀이행동 간의 관계)

  • Song, Hye-Rin;Rhee, Unhai
    • Korean Journal of Child Studies
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    • v.25 no.6
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    • pp.225-240
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    • 2004
  • Subjects were 15 teachers and 143 children at 15 child-care centers in Seoul that varied by quality of care. The Child Care Program Observation Scale(Rhee et at., 2003) was employed to observe the quality of the centers. Information on teachers' participation in play was collected by 20 units of observation for each teacher using a rating scale developed by the author. Children's behaviors were observed with time sampling method in 12 categories of play behaviors based on Social and Cognitive Play Scales(Rubin et al., 1978). Children's play behaviors varied by quality of child-care centers and teachers' participation in play. When child-care quality was high, teachers' participated actively in children's play and children showed developmentally appropriate play behaviors.

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Development of Shape Measurement System using 3 Dimension (3차원을 이용한 형상측정기 개발)

  • Lee, M.H.;Park, K.S.;Bae, J.I.;Kim, J.K.;Ahn, D.S.;Song, D.S.
    • Proceedings of the KIEE Conference
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    • 2001.07d
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    • pp.2628-2630
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    • 2001
  • This paper developed a 3D inspection system. The system consists of two parts : one includes hardwares such as actuators, linear scales and a probe, etc. the other involves softwares for management and control of the system. Compared with existing 3D measurement systems, this system achieved automatically the inspection. This automatic inspection makes the system have some advantages to reduce a measurement time and to be easily used by operators.

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Development of Automatic 3D Measurement System for Molding Inspection (금형 부품 검사를 위한 3차원 측정기 개발)

  • Eom, S.I.;Lee, Y.J.;Song, D.S.;Bae, J.I.;Lee, M.H.
    • Proceedings of the KIEE Conference
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    • 1999.07g
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    • pp.3070-3072
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    • 1999
  • We developed an automatic 3D inspection system. The system consists of two parts : one includes hardwares such as actuators, linear scales and a probe, etc. the other involves softwares for management and control of the system. Compared with existing 3D measurement systems, this system achieved automatically the inspection. This automatic inspection makes the system have some advantages to reduce a measurement time and to be easily used by operators.

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Flux Monitoring of Intraday Variable Sources with KVN Yonsei Radio Telescope

  • Lee, Jee-Won;Sohn, Bong-Won;Byun, Do-Young;Lee, Jeong-Ae;Park, Pulun;Kim, Min-Joong;Kim, Sung-Soo S.
    • Bulletin of the Korean Space Science Society
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    • 2010.04a
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    • pp.34.3-34.3
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    • 2010
  • We present the results of flux monitoring of BL Lac object 0716+71 and 0954+65 at 22GHz and 43GHz. Both of the flat spectrum radio sources are known as Intraday variables (IDVs) which are characterized by fast flux variation on time scales of a day or less. In general, the IDV phenomenon is interpreted as the effect of refractive scintillation in the interstellar medium or the evidence of source intrinsic flux variation. The observations were made simultaneously at 22GHz and 43GHz with KVN Yonsei 21m radio telescope.

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Reflectance Measurements of Soil Variability

  • Sudduth, K.A.;Hong, S.Y.;Hummel, J.W.;Kitchen, N.R.
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.1194-1196
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    • 2003
  • Variations in soil physical and chemical properties can affect agricultural productivity and the environmental implications of crop production. These variations are present and may be important at regional, field, and sub-field (precision agriculture) scales. Because traditional measurements are time-consuming and expensive, reflectance-based estimates of soil properties such as texture, organic matter content, water content, and nutrient status are attractive. Soil properties have been related to reflectance measured with laboratory, in-field, airborne, and satellite sensors. Both multispectral and hyperspectral instruments have been used, with both natural and artificial illumination. Varying levels of accuracy have been obtained, with the best results (r > 0.95) using hyperspectral reflectance data to estimate soil organic matter and water content.

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Dielectric Characteristics of Magnetic Tunnel Junction

  • Kim, Hong-Seog
    • The Journal of Engineering Research
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    • v.6 no.2
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    • pp.33-38
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    • 2004
  • To investigate the reliability of the MTJs on the roughness of insulating tunnel barrier, we prepared two MTJs with the different uniformity of barrier thickness. Namely, the one has uniform insulating barrier thickness; the other has non-uniform insulating barrier thickness as compared to different thing. As to depositing amorphous layer CoZrNb under the pinning layer IrMn, we achieved MTJ with uniform barrier thickness. Toinvestigate the reliability of the MTJs dependent on the bottom electrode, time-dependent dielectric breakdown (TDDB) measurements were carried out under constant voltage stress. The Weibull fit of out data shows clearly that $t_{BD}$ scales with the thickness uniformity of MTJs tunnel barrier. Assuming a linear dependence of log($t_{BD}$) on stress voltages, we obtained the lifetime of $10^4$years at a operating voltage of 0.4 V at MTJs comprising CoNbZr layers. This study shows that the reliabilityof new MTJs structure was improved due to the ultra smooth barrier, because the surface roughness of the bottom electrode influenced the uniformity of tunnel barrier.

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Particle Tracking Microrheology and its application to dilute viscoelastic materials (입자추적 미세유변학의 묽은 점탄성 물질에 대한 응용)

  • Yim Yoon-Jae;Lee Sung-Sik;Ahn Kyung-Hyun;Lee Seung-Jong
    • Proceedings of the Korean Society of Rheology Conference
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    • 2006.06a
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    • pp.61-64
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    • 2006
  • Soft materials, such as polymer solutions, gels and filamentous protein materials in cells, show complicated behavior due to their complex structures and dynamics with multiple characteristic time and length scales. Several complementary techniques have been developed to measure viscoelastic of soft materials. Especially, particle tracking microrheology, using the Brownian motion of particles in a medium to get rheological properties, has recently been improved both theoretically and experimentally. Compared to other conventional methods, video particle tracking microrheology has some advantages such as small sample volume, detecting spatial variation of local rheological properties, and less damage to sample materials. With these advantages, microrheology is more suitable to measure the properties of complex materials than other mechanical rheometries.

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A Study On Preprocessing of Fingerprint Image Using Multi-Scale Roof Edges (다척도 지붕에지 검출방법을 이용한 지문영상의 전처리에 대한 연구)

  • Kim Soo Gyeam
    • Journal of Advanced Marine Engineering and Technology
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    • v.29 no.2
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    • pp.217-224
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    • 2005
  • A new roof edge detection method based on multi level scales of wavelet function is proposed in this paper roof edge and its direction are obtained in this new methods at one time. Besides. scale characteristics of detecting roof edge is analyzed. And a few new methods on fingerprint image pre-processing are described. A method segmenting foreground/background of fingerprint images is proposed, in which Prior estimation of direction field is not required any more. A segmentation method based on multi-scale roof edges is implemented. and the valid scale range of the method is defined. too. And the method is used to segment ridges and valleys in fingerprint images simultaneously The exact direction fields made up of the direction of each point in ridges can be obtained when detecting ridges exactly based on the roof edge detector, in comparison with the traditional coarse estimation of direction fields. Obviously. it will establish a solid foundation for the sequent fingerprint identification.