• Current Optics and Photonics
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• v.3 no.4
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• pp.329-335
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• 2019

Wide FOV imaging systems are important for acquiring rich visual information. A conventional catadioptric imaging system deploys a camera in front of a curved mirror to acquire a wide FOV image. This is a cumbersome setup and causes unnecessary occlusions in the acquired image. In order to reduce both the burden of the camera deployment and the occlusions in the images, this study uses a secondary planar mirror in the catadioptric imaging system. A compact design of the catadioptric imaging system and a condition for the position of the secondary planar mirror to satisfy the central imaging are presented. The image acquisition model of the catadioptric imaging system with a secondary planar mirror is discussed based on the principles of geometric optics in this study. As a backward mapping, the acquired image is restored to a distortion-free image in the experiments.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.92-98
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• 2024

This meta-analysis systematically reviewed studies on mirror therapy focused on arm and hand function in stroke patients, aiming to comprehensively assess the efficacy of mirror therapy interventions and furnish empirical support for its potential application and future development in the context of stroke rehabilitation. A rigorous search for articles published in international journals up to the year 2022 was conducted. Various assessment tools were employed to calculate effect sizes, evaluating the impact of mirror therapy on arm and hand function in stroke patients. Utilizing a random-effects model, mean effect sizes were determined, yielding a total effect size of 0.545. The effect sizes for the Brunnstrom Recovery Stage (BRS), Box and Block Test (BBT), Modified Barthel Index (MBI), Fugl-Meyer Assessment (FMA), and grip strength test were 0.957, 0.596, 0.490, 0.488, and 0.417, respectively. In summary, we suggest that mirror therapy engenders positive changes in functional recovery among stroke patients, establishing a foundation for its tailored clinical application based on individual subject characteristics.

• Korean Journal of Optics and Photonics
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• v.14 no.4
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• pp.443-448
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• 2003

A study on optimum design of the lightweight mirror of a satellite camera is presented. An optical surface deformation of the lightweight mirror, which is a principal component of the camera system, is an important factor affecting the optical performance of the whole camera system. In this study, optimum design of the lightweight mirror is presented. Total weight of the mirror to reduce the optical surface deformation and the launching cost is used as an objective function. Peak-to-valley value and natural frequency of the mirror are given as constraints to the optimization problem. The sensitivities of the objective function and constraint are calculated by a finite difference method. The optimization procedure is carried out by the commercial optimizer, DOT. As a verification of the optimum design of the mirror, two design examples are treated. In the real application example, the lightweight mirror with 600mm effective diameter is treated. The optimized results with various design variables, which are obtained by considering thickness limitations, are analyzed.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.94-102
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• 2013

We propose the mirror active element pattern (AEP) method for the radiation pattern computation of linear array antennas versus scan angles. The computation time for the radiation pattern of linear array antennas using the mirror AEP method is reduced by almost half compared to that using the AEP method because the number of AEPs of elements obtained by the full-wave simulation necessary for the radiation pattern computation of linear array antennas is reduced by almost half. The difference between the radiation patterns of linear array antennas obtained by the full-wave simulation and mirror AEP method is very small for wide scan angle range when the radiation pattern of an antenna element is symmetric.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.4
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• pp.93-103
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• 2002

A new current mirror for high-accuracy current-mode signal processing and integrated circuit design was proposed. The current mirror adopts the technique of an adaptive feedback to reduce the input impedance and the output stage of regulated cascode current mirror to increase the output impedance. Simulation results show that the current mirror has input impedance of 0.9Ω, the output impedance of 415 MΩ, and current gain of 0.96 at the supply voltage Vcc=5V. The power dissipation is 1.5㎽. In order to certify the applicability of the proposed current mirror, a voltage-to-current converter using the current mirror is designed. Simulation results show that the converter has good agreement with theoretical equation and has three times better conversion characteristics when compared with voltage-to-current converter using Wilson current mirror.

• Korean Journal of Optics and Photonics
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• v.24 no.3
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• pp.111-119
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• 2013

A large aspheric mirror is a key component for large astronomical telescopes and high resolution satellite cameras. Since it is large and has an aspheric form, it is much more difficult to fabricate it compared to the similar size of spherical mirror. Especially, the opto-mechanical design and analysis is critical to reduce the deformation of mirror surface due to the external forces such as gravity or temperature change, as the mirror size is larger and lightweighting ratio is increased. The design requirements for the mirror are different depending on the particular ground and space applications because the environmental conditions are changed. In this paper, we explain the opto-mechanical design and analysis for ground and space applications that are among the most difficult to achieve among several technologies related to development of the large aspheric mirror.

• Korean Journal of Optics and Photonics
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• v.28 no.4
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• pp.146-152
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• 2017

Alignment of the mirrors composing a space telescope is an important process for obtaining high optical resolution and performance of the camera system. The alignment of mirrors using cube mirrors requires a relative coordinate mapping between the mirror and the cube mirror before optical-system integration. Therefore, to align the spacecraft camera mirrors, the relative coordinates of the vertex of each mirror and the corresponding cube mirror must be accurately measured. This paper proposes a new method for finding the vertex position of a primary mirror, by using an optical fiber and alignment segments of a computer-generated hologram (CGH). The measurement system is composed of an optical testing interferometer and a multimode optical fiber. We used two theodolites to measure the relative coordinates of the optical fiber located at the mirror vertex with respect to the cube mirror, and achieved a measurement precision of better than $25{\mu}m$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.116-121
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• 2005

To realize the tap coefficient of a finite impulse response(FIR) filter or the twiddle factor of a fast Fourier transform(FFT) using a current-mode analog circuit, a high accurate current-attenuator circuit is needed This paper introduces an accuracy enhancement technique in the current-mode signal processing. First of all, the DC of set-current error in a conventional current-attenuator using a gate-ratioed orient mirror circuit is analyzed and then, the current-attenuator circuit with a negligibly small DC offset-current error is introduced. The circuit consists of N-output current mirrors connected in parallel with me another. The output current of the circuit is attenuated to 1/N of the input current. On the basis of the Kirchhoff current law, the current scale ratio is determined simply by the number of the current mirrors in the N-current mirrors connected in parallel. In the proposed current-attenuator circuit the scale accuracy is limited by the ac gain error of the current mirror. Considering that a current mirror has a negligibly small ac gain error, the attainable maximum scale accuracy is theoretically -80[dB] to the input current.

• Journal of Korean Classical Literature and Education
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• no.15
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• pp.163-189
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• 2008

This paper is to reveal the relation between the epic of and paranoid personality disorder. I assume that the fact of not recognizing one's own face should be pathological problem. People who suffer from paranoid personality disorder show mistrust and anxiety. I expect that people who don't recognize their own faces from can be related to paranoid personality disorder. The epic of from "An Outline of Korean Folklore Literature" is related to the epic of mistrust and anxiety. The wife from distrusts her husband. She is in fear of being abandoned. She has a doubt that her husband has an affair, so she might lose him. After searching the epic of , I found some peculiarity of people's behave. When you have doubts about your lover, so you are in anxiety, it's hard to think logically. You keep digging for clues expecting that you would prove the unknown truth. It becomes really impossible to make a sense out of you. You cannot be persuaded. These all symptoms are related to paranoid personality disorder. Not every version of from "An Outline of Korean Folklore Literature" is all about symptoms. There are some versions show the solution. Separation for a specified period, self-examination, and recovery of distrust can be the way of solving the problem. In the scene of literary therapy practice, the epic of can be used for the treatment of paranoid personality disorder.

• Journal of the Korea Convergence Society
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• v.10 no.9
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• pp.161-166
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• 2019

This study examines the flows near the different side mirrors by analyzing the flow due to air resistance at A, B and C models of automotive side mirrors. Model A is a square-shaped side-mirror. Model B is a triangular side-mirror and model C is an oval-shaped side-mirror. The air resistance of the side-mirror while driving is reduced and the automotive power can be reduced by changing the design of automotive side-mirror. As analysis result, as the pressure of air resistance against side mirror becomes larger, it can be seen that the air flow rate becomes great. Therefore, it can be estimated that the smaller the pressure of air resistance, the smaller the flow rate and the better the air flow. Therefore, it can be acknowledged that model B is the best model. As the design data of the automotive side mirror obtained on the basis of this study result are utilized, the esthetic sense can be shown while driving a car at real life.