• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.453-454
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• 2007

This paper proposes the calculation method of voltage sensitivity index using CBEMA power acceptability curves and the voltage curves of the load bus to which momentary events occur. Voltage sensitivity index is represented by areas between two curves. Voltage sensitivity index is a parameter that depicts the ratio of a load disruption. The correlation between the installation cost of compensation devices and the voltage sag index on the bus can be used the validity of compensation.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.3
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• pp.437-444
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• 2015

Satellite selection and exclusion techniques have been applied to the global navigation satellite system (GNSS) with the aim of achieving a balance between navigational performance and computational efficiency. Conventional approaches to satellite selection based on the best dilution of precision (DOP) are excessively computational and complicated. This paper proposes a new method that applies a geometric sensitivity index of individual GNSS satellites. The sensitivity index is derived using the inner product of the line of sight (LOS) vector of each satellite. First, the LOS vector is computed, which accounts for the geometry between the satellite and user positions. Second, the inner product of each pair of LOS vectors is calculated, which indicates the proximities of the satellites to one another. The proximity can be determined according to the sensitivity of each satellite. A post-processing test was conducted to verify the reliability of the proposed method. The proposed index and the results of a conventional approach that measures the dilution of precision (DOP) were compared. The test results demonstrate that the proposed index produces results that are within 96% of those of the conventional approach and reduces the computational burden. This index can be utilized to estimate the sensitivity of individual satellites, obtaining a navigation solution. Therefore, the proposed index applies to satellite selection and exclusion as well as to the sensitivity analyses of multiple GNSS applications.

• Current Optics and Photonics
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• v.5 no.4
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• pp.444-449
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• 2021

A photonic crystal coupled-cavity waveguide created on silicon-on-insulator is designed to act as a refractive-index-sensing device at midinfrared wavelengths around 4 ㎛. To realize high sensitivity, effort is made to engineer the structural parameters to obtain strong modal confinement, which can enhance the interaction between the resonance modes and the analyzed sample. By adjusting some parameters, including the shape of the cavity, the width of the coupling cavity, and the size of the surrounding dielectric columns, a high-sensitivity refractive-index sensor based on the optimized photonic crystal coupled-cavity waveguide is proposed, and a sensitivity of approximately 2620 nm/RIU obtained. When an analyte is measured in the range of 1.0-1.4, the sensor can always maintain a high sensitivity of greater than 2400 nm/RIU. This work demonstrates the viability of high-sensitivity photonic crystal waveguide devices in the midinfrared band.

• 전자공학회논문지 IE
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• v.46 no.2
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• pp.18-21
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• 2009

The optical fiber refractive index sensors were fabricated using etching method and their refractive index characteristics have been investigated. Good sensitivity was shown at the region of 1.452-1.46 refractive index and operating point was shifted by wavelength. The sensitivity of sensor increased with decreasing cladding thickness and was stable with heat treatment. The hysteresis under cyclic refractive index changes was negligible.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.44 no.10
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• pp.1290-1294
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• 1995

In this paper, a new voltage collapse proximity index (VCPI) based on system apparent power loss sensitivity is proposed. The newly proposed index .lambda.$^{Sloss}$ reaches -.inf. at system voltage collapse point and can be represented by .root..lambda.$^{Ploss}$$^{2}$+.lambda.$^{Qloss}$$^{2}$ where .lambda.$^{Ploss}$ and .lambda.$^{Qloss}$ are the VCPI based on the system active and reactive power loss sensitivity respectively. These indices can be used for the system VAR investment. .DELTA.Q [VAR] is invested, step by step, by the priority of the VCPI index given for each bus. The indices use information from normal power flow equations and their Jacobians. Computation time for deriving .lambda.$^{Sloss}$ is almost same as that for power flow calculation. Two case studies prove the effectiveness of the .lambda.$^{Sloss}$ index and the VAR investment algorithm proposed.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.221-223
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• 2003

In this paper, a sensitivity index is proposed for identifying the location of FACTS in the power system with PSS. The index can be calculated by using the bus impedance matrix of the power system. This index that is related with sensitivity matrix is included in the network and not in operating condition for power system. This index is applied to IEEE 9 bus test system.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.1
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• pp.92-100
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• 2003

Using a quarter car model, an analytic method for performance estimation of a vehicle suspension system with respect to frequency response, RMS response and performance index is presented. From frequency response function, compromization of response performance to the whole frequency range is verified and from RMS response and performance index, sensitivity of ride md handling characteristics are examined. Using a full car model, sweet area(stable ride area) are determined and performance sensitivity is estimated according to the change of feedback gains. In order to esimate the output sensitivity, response we is displayed using a 3-dimensional contour plot. Design data n suggested for optimal design parameter esimation, which maximize the performance of the given suspension system.

• Transactions of Materials Processing
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• v.20 no.7
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• pp.498-503
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• 2011

The strain rate sensitivity index, m, plays an important role in plastic deformation at elevated temperatures. It is affected by strain rate, temperature, and the microstructure of the material. The strain rate sensitivity index has been used as a constant in numerical analysis of plastic forming at a specified strain rate and temperature. However, the value of m varies as deformation proceeds at an elevated temperature and a certain strain rate. Thus, in this present study, the value of m has been characterized as a function of strain by multiple tensile jump tests for AZ31 magnesium alloy sheet, and the variation of m has been discussed in conjunction with the microstructural observations before and after deformation. The experimental results show that the variation of m is dependent on the temperature and strain rate. Grain growth with dynamic recrystallization also affects the variation of m.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.44 no.1
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• pp.21-24
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• 1995

The larger and the more complicated the system size and configuration grow, the more serious the system loss problem becomes. Exessive system loss causes severs system voltage depression, which even may result in system voltage collapse. This paper proposes an effective tool for minimizing the system power loss by optimal re-location of the static condenser based on the system loss sensitivity index .lambda.$_{Q}$. It is possible to determine the optimal location and amount of VAR investment for minimizing the system loss by priority of .lambda.$_{Q}$ index given for each bus. Several computational techniques for avoiding divergency of the load flow solution are proposed. The loss sensitivity index .lambda.$_{Q}$ uses information of normal power flow equations and their Jacobians. Two case studies proved the effectiveness of the algorithm proposed.posed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1464-1473
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• 1990

Optimal design parameters are estimated from the sensitivity function and performance index variation. Suspension design modification for performance improvement and basic materials for practical applications are presented. The linear quarter model of a vehicle suspension is analyzed in order to represent the utilities of sensitivity analysis, and sensitivity function is determined in the frequency domain. The change of frequency response function is predicted, which depends on the design parameter variation and the property is verified by computer simulation. As an investigation results of sensitivity function for the vibrational amplitude of sprung mass to road profile input, it is shown that the most sensitive parameters are the suspension damping and the suspension stiffness. In order to identify the effects of these two parameters to the performance of suspension system, the performance index variation according to the changes of parameters is considered and then optimal design parameters are determined. It is verified that the system response is improved noticeably in the both of frequency and time domain after the design modification with the optimal parameters.