• Journal of Institute of Control, Robotics and Systems
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• v.4 no.6
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• pp.747-752
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• 1998

Ultrasonic sensors have been widely used to recognize the working environment for a mobile robot. However, their intrinsic problems, such as specular reflection, wide beam angle, and slow propagation velocity, require an excessive number of sensors to be integrated for achieving the sensing goal. This paper proposes a new measurement scheme which uses only two sets of ultrasonic sensors to determine the location and the type of a target surface. By measuring the time difference between the returned signals from the target surface, which are generated by two transmitters with 1 ㎳ difference, it classifies the type and determines the size of the target surface. Since the proposed sensor system uses only two sets of ultrasonic sensors to recognize and localize the target surface, it significantly simplifies the sensing system and reduces the signal processing time so that the working environment can be recognized in real time.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.3
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• pp.433-436
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• 2012

We propose a novel micro surface plasmon resonance (SPR) sensor system based on polymer materials. The proposed SPR system consists of the incident medium with polymer waveguide and the gold thin film for sensing area. Using a polymer optical waveguide instead of a prism in SPR sensing system offers miniaturization, low cost, and potable sensing capability. The whole device performance was analyzed using the finite-difference time domain method. The optimum gold thickness in the attenuated total reflection mirror of polymer waveguide is around 50 nm and the resonance angle to generate surface plasmon wave is 68 degrees.

• Proceedings of the Acoustical Society of Korea Conference
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• 1996.10a
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• pp.14-18
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• 1996

쐐기각이 다른 4종류의 쐐기형 흡음타일을 설계,제작하고 각각의 흡음타일에 대한 음파 반사계수를 측정하였다. 흡음타일의 정면에서 측정한 반사계수는 실험한 4개의 타일중 쐐기의 꼭지각이 30$^{\circ}$일 때 최소값을 갖고 120$^{\circ}$ 일 때 최대값을 가졌다. 쐐기형 흡음타일의 꼭지각이 클수록 그 반사계수가 증가되는 것을 확인하였다. 또한 쐐기의 꼭지각이 같은 종류의 타일헤서는 본 실험에 사용한 10kHz~30kHz 입사음파의 주파수와 측정한 반사계수는 무관함을 보였다. 그리고 쐐기형 흡음타일 후면에서 측정한 반사계수는 타입에 관계없이 일정하게 나타났다.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.957-960
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• 2002

We propose an optical configuration of a hybrid-aligned nematic liquid crystal cell for reflective displays by which we can achieve wide viewing angle and uniform reflection spectrum.

• Journal of Fashion Business
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• v.9 no.4
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• pp.170-177
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• 2005

Velvet fabric has soft touch, subtle luster, and good draping property. Threedimensional simulated models of cylindrical monofilaments constituting the velvet fabric were prepared. Image analysis techniques were used to measure the reflected light from the surface of velvet fabrics and the simulated images of the pile fibers. As the angle of incidence increased, the reflectance from the velvet surface became lower. Most of the reflection came from the tips of the cut piles. Crushed velvet type also was modeled using slant cylinder models on top of a base plate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.3
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• pp.753-762
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• 1996

In this paper, aperture coupled stacked microstrip array antennas are proposed and their operating characteristics are analyzed based on analytical. In order to evaluate mutual coupling between slot-coupled microstrip patches in finite array, analysis uses the reciprocity theorem and the spectral domain Green's functions for dielectric slab in a moment method solution for the unknown patches and solts current distrbution. By introducing an N-port equivalent network, the impedance matrix of an affay of N-element slot-coupled patches is evaluated directly from its network current matix of order N$^{2}$, and it can be programmed to be run on a PC. Numerical results show mutual coupling, radiation pattern, active reflection coefficient versus scan angle, radiation efficiency and active element gain pattern.

• Korean Journal of Optics and Photonics
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• v.13 no.6
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• pp.515-520
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• 2002

The variation of the optical pass length between incident and reflective beam in a multilayer thin film reflection mirror is investigated. This variation is caused mainly by environmental parameters around the optical system, such as the air pressure, temperature, humidity and $CO_2$concentration. In this paper, a new method for measuring optical pass length variation is proposed. This optical pass length is measured against the above parameters by experiment. From the experimental results, it is clarified that the optical pass length is mostly effected by humidity changes.

• Journal of the Optical Society of Korea
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• v.12 no.3
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• pp.174-177
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• 2008

The luminance properties of FFL(Flat Fluorescent Lamp) backlights have been investigated in detail for the first time. The on-axis luminance gain as well as viewing-angle characteristics on various combinations of optical films were obtained from FFL backlight and compared to the results of conventional CCFL(cold-cathode fluorescent lamps) backlights. It was found that the on-axis luminance gains achieved by using optical films in the FFL backlight were lower than those in the CCFL backlight indicating that the recycling processes occurring between optical films and light sources/reflection sheet are not so effective in the FFL backlight due to the much larger area of, and thus higher absorption probability of the FFL. This result suggests that new optical films should be developed for FFL backlight and other flat-lamp backlight technologies.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.5
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• pp.590-595
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• 2003

In this paper, we propose a new method to the speed control of soccer robot using messy Genetic Algorithm(mGA). In order to arrive in the target of the soccer robot within the smallest time ,we propose the speed control function with several parameters which represent the reflection ratio distance and angle error. Also, we propose the algorithm for searching these parameters by using messy Genetic Algorithm. As a result of finding the optimal parameters, we can move the robot the most quickly in the target under the complex environment.

• Steel and Composite Structures
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• v.27 no.4
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• pp.439-451
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• 2018

In the present investigation, a plane P (longitudinal) wave is made incident upon a transversely isotropic magnetothermoelastic solid slab of uniform thickness, interposed between two different semi-infinite viscoelastic solids. The transversely isotropic magnetothermoelastic sandwiched layer is homogeneous with combined effects of two temperature, rotation and Hall current in the context of GN Type-II and Type-III (1993) theory of thermoelasticity. The amplitude ratios of various reflected and refracted waves are obtained by using appropriate boundary conditions. The effect of energy dissipation on various amplitude ratios of longitudinal wave with angle of incidence are depicted graphically. Some cases of interest are also deduced from the present investigation.