• Journal of Korea Society of Industrial Information Systems
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• v.4 no.2
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• pp.7-13
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• 1999

This paper propose a fuzzy regression method using fuzzy neural networks when a membership value is attached to each input -output pair. First, an architecture of fuzzy neural networks with fuzzy weights and fuzzy biases is shown. Next, a cost function is defined using the fuzzy output from the fuzzy neural network and the corresponding target output with a membership value. A learning algorithm is derived from the cost function. The derived learning algorithm trains the fuzzy neural network so that the level set of the fuzzy output includes the target output. Last, the proposed method is applied to the quality evaluation problem of injection molding

• Journal of the Korean Solar Energy Society
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• v.27 no.3
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• pp.23-28
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• 2007

In this study, we analyzed the maximum output power characteristics of crystalline silicon photovoltaic module by change of environmental effects. The electrical, optical and thermal property of PV modules were investigated during outdoor test period about 70 days. There was a fluctuation in maximum output power by change in transmittance caused by environment effects like rain, snow and dust. The effects of external environmental change were analyzed using climate data. Also local thermal temperature variation and transmittance imbalance on surface of PV module which might lead degradation of constituent material were detected using infrared camera. The further analysis is describe in the following paper.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.349-354
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• 1999

Electro-Optical Camera (EOC) is the main payload of the KOMPSAT-1 satellite to perform the mission of cartography that builds up a digital map of Korean territory including a digital terrain elevation map. This paper discusses the issues of the digital image simulation of EOC for the generation of EOC simulated scene as taken by EOC at 685km altitude on orbit. For the purpose, simulation work has been performed with the sensor models of EOC and the satellite platform motions models through image chain analysis from the illumination source (Sun) to a simulated image output in digital number. MODTRAN fur radiance calculation, MTF models of optics, detector and motions of EOC for system point spread function (PSF), and signal chain equations for digital number output are described. Several noise models of EOC are also considered. The final output is the EOC simulated image in digital number. The simulation technique can be used in several phase of a spaceborne electro-optical system development project, feasibility study phase, design, manufacturing, test phases, ground image processing phases, and so on.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2051-2053
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• 1998

In spite of nonlinear or step-changing load and line disturbances, the inverter for the UPS must provide the pure sinusoidal output voltage with low THD(Total Harmonics Distortion). This paper proposes an inverter controller for the UPS which has a good dynamic response characteristic and robustness for applying industrial world directly. The inverter output voltage is controlled instantaneously with a double regulation loop by a TMS320C31 Digital Signal Processor so that it has very good dynamic response for nonlinear or step-changing load and line disturbances. To improve the voltage utilization and response characteristics, the Space Vector Modulation(SVM) technique is adapted for the switching method of this system. The characteristics of the proposed control system were verified by simulations and experiments.

• ETRI Journal
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• v.45 no.2
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• pp.193-202
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• 2023

We demonstrate the transmission of uncompressed 4K videos over the photonics-based terahertz (THz) wireless link using a directly modulated distributed feedback laser diode (DFB-LD). For optical heterodyne mixing and data modulation, a DFB-LD was employed and directly modulated with a 5.94-Gb/s non-return-to-zero signal, which is related to a 6G-serial digital interface standard to support ultra-high-definition video resolution. We derived the optimal frequency of the THz carrier by varying the wavelength difference between DFB-LD output and Tunable LD output in the THz signal transmitter to obtain the best transmission performances of the uncompressed 4K video signals. Furthermore, we exploited the negative laser-to-filter detuning for the adiabatic chirp management of the DFB-LD by the intentional discrepancy between the center wavelength of the optical band-pass filter and the output wavelength of the DFB-LD. With the help of the abovementioned methods, we successfully transmitted uncompressed 4K video signals over the 2.3-m wireless transmission distance without black frames induced by time synchronization error.

• Journal of Power System Engineering
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• v.3 no.4
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• pp.69-78
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• 1999

In the single-input and single-output system, the parameter of plant is scalar polynomial, but in the multiple input and multiple output, it accompanies, being matrix polynomial, the consideration of observable controlability index or problems non-commutation in matrix polynomial as well as degree, and it is more complex to deal with. Therefore, it is thought that a full research on the single-input and single-output system is not sufficient. This paper proposes that problems of minimum variance self-tuning regulator by using numerical calculation example of multivariable system and pole assignment self-tuning regulator.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1997.10a
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• pp.197-200
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• 1997

Each company is more interested in the productivity to achieve cost reduction and profit maximization through productivity improvement. With this trend, we show the method to measure productivity using TPM(Total Productivity Model) which considers all the input factors of the company instead of using partial productivity such as labor and/or capital productivity We also examine the relation of productivity versus output, profit versus output and profit versus productivity of the case company by actually applying the TPM and suggest the optimal level of profit and output for this company.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.791-794
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• 2004

This paper made an induction heating inverter. The inverter is the $20\~40[kHz]$ a resonant inverter which uses a high frequency. We use this inverter and use induction heating. A phasor shift ordered a gate signal to adjust an inverter's output. We verified an output waveform according to the situation of a gate signal through the simulation. We made the inverter really and got the result.

• Korea Trade Review
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• v.46 no.1
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• pp.83-111
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• 2021

This paper conducts a Structural Dcomposition Analysis on the structure of factors contributing to the output growth of Korean Maritime and Port Industry during year 2000~ year 2017. Some of results are as follows. The output growth rates of the industry (yearly average 4.3%) was far lower than the average growth rates of Service as well as of Manufacturing Industries (yearly average 9% and 6.8%, respectively) due to the lower output growth of Maritime Industry. Among the growth contributing factors, change in domestic demand for final goods is the first contributing factor, and then change in technology, change in export and import substitution for intermediate goods are followed in order, but import substitution for final goods decreased its output. However, in each respective sub-periods of pre-global financial crisis and post-global financial crisis, change in the export, especially change in the export of Maritime Industry is the dominant determinant of output change in the Maritime and Port Industry in opposite ways. In the periods of the former the increase in the export of Maritime Industry overwhelmingly led the output growth of the Maritime and Port industry, but in the periods of the latter the decrease in its export was the culprit of lower output growth of the industry. On the other hand, among all industries of service and manufacturing sectors, Wholesale and Retail industry is the leading industry in contributing to the output growth of the Maritime and Port Industry, and Transportation Equipment industry is the leading industry among all manufacturing industries.

• Current Photovoltaic Research
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• v.8 no.4
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• pp.124-128
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• 2020

Output power of photovoltaic (PV) modules installed outdoors decreases every year due to environmental conditions such as temperature, humidity, and ultraviolet irradiations. In order to promote the installation of PV modules, the reliability must be guaranteed. One of the important factors affecting reliability is intermetallic compounds (IMC) layer formed in ribbon solder joint. For this reason, various studies on soldering properties between the ribbon and cell have been performed to solve the reliability deterioration caused by excessive growth of the IMC layer. However, the IMC layer of the PV module interconnected by multi-wires has been studied less than using the ribbon. It is necessary to study soldering characteristics of the multi-wire module for improvement of its reliability. In this study, we analyzed the growth of IMC layer of the PV module with multi-wire and the degradation of output power through damp-heat test. The fabricated modules were exposed to damp-heat conditions (85 ºC and 85 % relative humidity) for 1000 hours and the output powers of the modules before and after the damp-heat test were measured. Then, the process of dissolving ethylene vinyl acetate (EVA) as an encapsulant of the modules was performed to observe the IMC layer. The growth of IMC layer was evaluated using OM and FE-SEM for cross-sectional analysis and EDS for elemental mapping. Based on these results, we investigated the correlation between the IMC layer and output power of modules.