• Journal of the Korean Society of Industry Convergence
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• v.21 no.2
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• pp.71-78
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• 2018

In this paper, we propose the performance enhancement of solar individual string power generation system using booster power control for voltage compensation. The proposed control method determines the variable voltage for the compensator using direct power control (DPC) modeling applied to motion factor estimation. This method also maintains excellent dynamic response to the characteristics of direct power control (DPC) by calculating the mismatch ratio of the arrestered PV modules. The validity of the proposed algorithm is verified through simulation and experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.731-736
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• 2000

The vibration of an axially moving string is studied when the string has geometric non-linearity and translating acceleration. Based upon the von karman strain theory, The equation for the longitudinal vibration is linear and uncoupled, while the equation for the transverse vibration is non-linear and coupled between the longitudinal and transverse deflections. The governing equations are discretized by using the Galerkin approximation. With the discretized nonlinear equations, the time responses are investigated by using the generalized-${\alpha}$ method.

• Journal of Industrial Technology
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• v.19
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• pp.321-329
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• 1999

An automated manufacturing process mechanism for string musical instruments has been designed in this study. In contrast to other manufacturing products, classical string instruments try to preserve their traditional design shapes even in these days and involve variety of wood working(carpentry) characteristics including highly skilled curved surfaces treatments. Great efforts have been put to develop an integrated and automated system for improved product quality and process control, reduced physical labors, better safety etc. They, however, have been limited to devise jigs and tools with regard to selected processes due to lack of technology and research man-powers. We carefully examined the products and process characteristics, and an automated mechanism which overcome prevailing drawbacks has been derived.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.154-157
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• 2008

In korea, PV business has been growing fast since 2000. There are many ways to build PV module Among them, BIPV system(BIPV : building integrated system) using PV modules as external wall has been carried out research on and invested much. I suggest another way to apply the BIPV system BIPV SU(string unit) module is easier and faster to be installed and more economical than other BIPV module. In this paper. I will show how to make, and how to install this BIPV SU module.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.4
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• pp.69-76
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• 2008

The self-organizing feature map(SOFM) among a number of neural network uses a randomized small valued initial weight vectors, selects the neuron whose weight vector best matches input as the winning neuron, and trains the weight vectors such that neurons within the activity bubble are moved toward the input vector. On the other hand, the modified method in this research uses a predetermined initial weight vectors of the 1-dimensional string, gives the systematic input vector whose position best matches obstacles, and trains the weight vectors such that neurons within the activity bubble are move toward the opposite direction of input vector. According to simulation results one can conclude that the method using string and the modified neural network is useful tool to mobile robot for the global path planning.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.416-420
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• 2002

This Paper describes a matched-filter type strain sensor system using optical fiber Bragg grating (FBG) sensor. Matched-filter type uses another wavelength-matched FBG filter to track wavelength shift in the FBG sensor. Filter FBG is attached on a fiber stretcher and stretched by PZT actuator. To overcome the nonlinearity and hysteresis of the PZT actuator that degrades system accuracy, a string resonator which can measure an absolute strain is employed. And the effect of vibration modes on string resonator is investigated particularly regarding its sensitivity and stability.

• Journal of KSNVE
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• v.10 no.5
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• pp.838-842
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• 2000

The vibration of an axially moving string is studied when the string has geometric non-linearity and translating acceleration. Based upon the von karman strain theory, the equations of motion are derived considering the longitudinal and transverse deflection. The equation for the longitudinal vibration is linear and uncoupled, while the equation for the transverse vibration is non-linear and coupled between the longitudinal and transverse deflections. These equations are discretized by using the Galerkin approximation after they are transformed into the variational equations, i.e. the weak forms so that the admissible and comparison functions can be used for the bases of the longitudinal and transverse deflections respectively. With the discretized nonlinear equations, the time responses are investigated by using the generalized-$\alpha$ method.

• Journal of Korean Association for Spatial Structures
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• v.13 no.4
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• pp.49-56
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• 2013

Beam string structures(BSS) are one kind of efficient structure system because the bending moment in the beams is reduced greatly through the struts and the strings. As the struts in BSS are used as middle supports to the beam and always in compression, the buckling of the struts should be avoided. This paper investigates the lateral buckling of the struts in BSS. Firstly, the strut of a one-strut BSS is simplified into an analytical model by considering load is formulated and some special cases of the model are analyzed. Finally, the lateral buckling load of the strut is numerically examined by means of parameter studies. It is known that, because on end of the struts is jointed to the beam while the other end is connected to the strings, the buckling of the struts not only depends on the length of the struts and the stiffness of the joints, but also depends on the rise and the lateral stiffness of the beam, the layout of the strings and the number of the struts.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.3
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• pp.390-396
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• 2015

This paper proposes a method to reduce flicker when running an AC-power direct-drive type multiple string LED driver IC. The proposed method greatly decreases flicker using one capacitor and P-type MOSFET transistor (PMOS). The flicker index (FI) was reduced by over 40% through experiments, and less than half of the conventional external components are used in the passive valley fill circuit, which gives an advantage in the cost and utilization in the design of LED lighting modules. The 0.35 um 700 V BCD process was used to manufacture this LED driver.

• Journal of the Korean Solar Energy Society
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• v.29 no.1
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• pp.58-63
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• 2009

In this paper, the power loss due to PV module mismatch in PV string is analyzed and a mismatch compensation method is proposed to improve the efficiency of PV system. The analysis of mismatch loss using PV model simulation reveals that the mismatch module may decrease the total efficiency because the MPPT function of power conditioner make the PV system operate at the local maximum point. The mismatch loss can be severe if the maximum power point current of mismatch module is less than that of string. The proposed compensation method which is simply implemented with a buck type converter shows the possibility to remove the mismatch loss. The effectiveness of the analysis and compensation method is verified by a prototype experiment.