• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.12 no.3
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• pp.153-160
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• 2008

A size-biased Poisson distribution is defined. Its characterization by using a recurrence relation for first order negative moment of the distribution is obtained. Different estimation methods for the parameter of the model are also discussed. R-Software has been used for making a comparison among the three different estimation methods.

• 한국약용작물학회:학술대회논문집
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• 2011.04a
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• pp.252-253
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• 2011

• Journal of Biomedical Engineering Research
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• v.7 no.1
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• pp.41-44
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• 1986

The objective of tissue characterization is to provide quantitative information about the physical state of tissue interrogated by an ultrasound beam. In the computer simulation, it was found that the echoes were composed of the interferences of the ultrasonic waves reflected from both sides of the thin object, and could be separated by the spectral correlation method. Also, the phantom study demonstrates that thickness of the thin acryl layer beyond the resolution of common ultrasonic imaging systems can be measured- using this method.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2300-2302
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• 2005

Metal-Semiconductor-Metal type photodetector was fabricated with AlGaAs/InGaAs Quantum Well FET structures using simplified processing steps. The DC and RF responses were measured by 850nm wavelength injection laser. A DC responsivity in the quasisaturated regime was 0.45 A/W in CW measurements, and a bandwidth measured using a 850nm 40 ps pulsed laser was 16GHz. An electrical equivalent circuit model was extracted from measured S-parameter.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.103-104
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• 2015

Solar energy has proven to be a potential clean energy source to help offset the large consumption of fossil. Nowadays, many research projects aim to enhance photovoltaic (PV) system performance and functionality. This research focuses on integrating self-monitor capability into dc-dc converters that control PV panels to detect a fault in series-connected PV cells, called hot spotting. A detection method using ac parameter characterization is proposed and its operation is examined through simulation.

• Journal of the Korean Mathematical Society
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• v.59 no.3
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• pp.469-494
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• 2022

In this paper, we study the boundedness of a class of inhomogeneous Journé's product singular integral operators on the inhomogeneous product Lipschitz spaces. The consideration of such inhomogeneous Journé's product singular integral operators is motivated by the study of the multi-parameter pseudo-differential operators. The key idea used here is to develop the Littlewood-Paley theory for the inhomogeneous product spaces which includes the characterization of a special inhomogeneous product Besov space and a density argument for the inhomogeneous product Lipschitz spaces in the weak sense.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.4
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• pp.491-498
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• 2012

A Ground Based Augmentation System (GBAS) is an enabling technology for an aircraft's precision approach based on a Global Navigation Satellite System (GNSS). However, GBAS is vulnerable to interference, so effective GNSS interference detection and mitigation methods need to be employed. In this paper, an intentional GNSS interference detection and characterization algorithm is proposed. The algorithm uses Automatic Gain Control (AGC) gain and adaptive notch filter parameters to classify types of incoming interference and to characterize them. The AGC gain and adaptive lattice IIR notch filter parameter values in GNSS receivers are examined according to interference types and power levels. Based on those data, the interference detection and characterization algorithm is developed and Monte Carlo simulations are carried out for performance analysis of the proposed method. Here, the proposed algorithm is used to detect and characterize single-tone continuous wave interference, swept continuous wave interference, and band-limited white Gaussian noise. The algorithm can be used for GNSS interference monitoring in an excessive Radio Frequency Interference environment which causes loss of receiver tracking. This interference detection and characterization algorithm will be used to enhance the interference mitigation algorithm.

• Korean journal of food and cookery science
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• v.4 no.1
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• pp.17-26
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• 1988

The polysaccharide produced by pseudomonas elodea, Gellan gum, was rheologically characterized, compared with agar. Rheological properties were determined from the change in the value of intrinsic viscosity with the pH and salt concentration. At the range of pH 2∼ll and salt 0∼0.16M KC1, the intrinsic viscosity of Gellan gum ranged from 8.8 to 21.2dl/g and agar ranged from 1.97 to 11.46d1/g. In the absence of salt, the intrinsic viscosity of Gellan gum increased as the pH of solution increased up to neutral pH then decreased slightly at alkaline pH, whearas the intrinsic viscosity of agar increased as the pH of solution increased up to pH 9 then decreased slightly. Intrinsic viscosity of Gellan gum and agar decreased with an increase in salt concentration. The chain stiffness parameter for the Gellan gum was 0.033. The overlap parameter of Gellan gum and agar were 0.047g/dl and 0.087g/dl, respectively. Gellan gum and agar were shear rate dependent or pseudoplastic. The yield stress and proportionality constant of Gellan gum increased slightly as the concentration increase, on the other hand, the shear index of Gellan gum showed a maximum at 0.75g/dl and gradually decreased as the concentration increase. The apparent viscosity of Gellan gum and agar decreased as the temperature increase. A lower concentration of the divalent cations calcium and magnesium is required to obtain maximum gel strength than for the monovalent cations sodium and potassium.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.229-238
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• 2002

This paper introduces the surface roughness parameter, Rs to the characterization of joint roughness and quantitatively illustrates the influence of joint roughness on the joint shear strength. A new peak shear strength criterion for rock joints using Rs is suggested. The results show that the surface roughness parameter, Rs can appropriately reflect the degree of roughness for the rock joint surfaces tested in this study A measuring interval of 2mm and profile length of 5cm can be used to characterize the joint roughness of the rock core size surfaces; however, the scale of fluctuation, $\delta_\alpha$ should be considered to extend the surface roughness parameter, Rs to the large-scale field rock joint surfaces. For the smooth joint roughness, sliding of the rock cores is the principal shear mechanism; however, the breakage of roughness from the rock cores is inferred for rougher joint roughness.

• Current Optics and Photonics
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• v.6 no.5
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• pp.445-452
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• 2022

We developed an adaptive optics test bench using an optical simulator and two rotating phase plates that mimicked the atmospheric turbulence at Bohyunsan Observatory. The observatory was reported to have a Fried parameter with a mean value of 85 mm and standard deviation of 13 mm, often expressed as 85 ± 13 mm. First, we fabricated several phase plates to generate realistic atmospheric-like turbulence. Then, we selected a pair from among the fabricated phase plates to emulate the atmospheric turbulence at the site. The result was 83 ± 11 mm. To address dynamic behavior, we emulated the atmospheric disturbance produced by a wind flow of 8.3 m/s by controlling the rotational speed of the phase plates. Finally, we investigated how closely the atmospheric disturbance simulation emulated reality with an investigation of the measurements on the optical table. The verification confirmed that the simulator showed a Fried parameter of 87 ± 15 mm as designed, but a little slower wind velocity (7.5 ± 2.5 m/s) than expected. This was because of the nonlinear motion of the phase plates. In conclusion, we successfully mimicked the atmospheric disturbance of Bohyunsan Observatory with an error of less than 10% in terms of Fried parameter and wind velocity.