• Journal of applied mathematics & informatics
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• v.17 no.1_2_3
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• pp.787-796
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• 2005

We generalize a characterization of classical orthogonal polynomials and obtain a two-variable analogue. Also an example is given arising from a second order partial differential equation.

• Journal of Korean Society for Quality Management
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• v.32 no.4
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• pp.220-228
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• 2004

The orthogonality is an important property in the experimental designs. When we use nearly orthogonal arrays, we need evaluate the degree of the orthogonality of given experimental designs. Graphical methods for evaluating the degree of the orthogonality of nearly orthogonal arrays are suggested.

• Korean Journal of Mathematics
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• v.7 no.1
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• pp.61-69
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• 1999

We determine sparse orthogonal matrices of order $n$ which is fully indecomposable by weaving.

• Korean Journal of Mathematics
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• v.7 no.2
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• pp.281-283
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• 1999

The structure of orthogonal groups of quaternion algebras is studied.

• Journal of the Chungcheong Mathematical Society
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• v.20 no.1
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• pp.47-49
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• 2007

We compute the special orthogonal group of certain lattice of signature (2, 1).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.4
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• pp.80-87
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• 2007

This paper will suggest that the 1 cross orthogonal loop type sensor improves on the orthogonal loop form sensor-head, which is available a calibration of the linear birefringence, when a fiber optic current sensor was composed. An output characteristics of the 1 cross orthogonal loop form, a general closed loop form, the orthogonal loop form are compared by the IEC(International Electrotechnical Commission) 60044-8 standard, and the state of polarization is compared with three forms. As a result, when the closed loop form was changed to the orthogonal loop form, retardation decreased 15.3[%]. When the closed loop form was changed to the 1 cross orthogonal loop type, the retardation decreased 33.8[%]. As a result of the Faraday Effect measurement, the 1 cross orthogonal loop form has the highest output characteristic and the lowest error ratio. It met the 0.5 class of the IEC 60044-8 standard. Thus, in application of the 1cross orthogonal loop form, the possibility to develop high reliability fiber optic current sensors that have a high output and stable error ratio rises is increased.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.1
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• pp.34-41
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• 2010

In this paper, we analyze and simulate co-channel interference (CCI) mitigation method for cooperative communication systems employing decode-and-forward relays. In co-channel interference mitigation method, A source transmits signals that are encoded by orthogonal code. Then, the receiver can distinguish its own signals form the received signals by using the orthogonal code which is already known to the receiver. The orthogonal codes applied to this paper are orthogonal Gold codes. However, we can employ other codes, which have orthogonality, as the orthogonal code. In addition, we utilize a space time block coding (STBC) scheme for enhancing the system performance by obtaining additional array gain.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1601-1607
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• 2009

As a general rule, the orthogonal modulation scheme which is widely used for wireless communications is not appropriate for the high speed data transmission applications due to the low bandwidth efficiency. Therefore, to increase the bandwidth efficiency of the conventional orthogonal modulation, we propose the multi-code trans-(bi-)orthogonal modulation in this paper. It is the combined scheme of multi-code modulation and trans-orthogonal modulation. We can know that the bandwidth efficiency of the proposed scheme is better than that of the conventional orthogonal modulation. Additionally, the receiver complexity of the proposed scheme is lower than that of the conventional orthogonal modulation. The proposed scheme can be used for the physical layer of the high speed wireless digital data transmission applications such as multimedia communications system and high speed personal area networks.

• Journal of applied mathematics & informatics
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• v.17 no.1_2_3
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• pp.343-350
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• 2005

In this paper we prove two results about tilings of orthogonal polygons. (1) P be an orthogonal polygon with rational vertex coordinates and let R(u) be a rectangle with side lengths u and 1. An orthogonal polygon P can be tiled with similar copies of R(u) if and only if u i algebraic and the real part of each of its conjugates is positive; (2) Laczkovich proved that if a triangle $\Delta$ tiles a rectangle then either $\Delta$ is a right triangle or the angles of $\Delta$ are rational multiples of $\pi$. We generalize the result of Laczkovich to orthogonal polygons.

• Journal of Communications and Networks
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• v.5 no.4
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• pp.328-343
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• 2003

Orthogonal pulse-shape modulation using Hermite pulses for ultra-wideband communications is reviewed. Closedform expressions of cross-correlations among Hermite pulses and their corresponding transmit and receive waveforms are provided. These show that the pulses lose orthogonality at the receiver in the presence of differentiating antennas. Using these expressions, an algebraic model is established based on the projections of distorted receive waveforms onto the orthonormal basis given by the set of normalized orthogonal Hermite pulses. Using this new matrix model, a number of pulse-shape modulation schemes are analyzed and a novel orthogonal design is proposed. In the proposed orthogonal design, transmit waveforms are constructed as combinations of elementary Hermites with weighting coefficients derived by employing the Gram-Schmidt (QR) factorization of the differentiating distortion model’s matrix. The design ensures orthogonality of the vectors at the output of the receiver bank of correlators, without requiring compensation for the distortion introduced by the antennas. In addition, a new set of elementary Hermite Pulses is proposed which further enhances the performance of the new design while enabling a simplified hardware implementation.