• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.581-582
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• 2010

This paper performed the basic study for developing the Photodynamic Therapy Equipment for medical treatment. We developed the equipment palpating cell proliferation using a high brightness LED. This equipment was fabricated using a micro-controller and a high brightness LED, and designed to enable us to control light irradiation time, intensity, frequency and so on. Especially, to control the light irradiation frequency, FPGA was used, and to control the change of output value, TLC5941 was used. Control stage is divided into 30 step by program. Consequently, the current value could be controlled by the change of level in Continue Wave(CW) and Pulse Width Modulation(PWM), and the output of a high brightness LED could be controlled stage by stage.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.130-132
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• 2007

Recently, regulation for THD(Total Harmonic Distortion) such as IEC 61000-3-2, IEEE 519 is being reinforced about a product which directly connects to AC line in order to prevent distortion of common power source in electronic equipment and electrical machinery. In order to satisfy these regulations, conventional circuits were used two-stage structure attached power factor correction circuit at ahead of converter but this method complicate the circuit and then a number of element increases thereupon the cost of production rises. In this paper, we propose a high efficiency single-stage 300W PFC flyback converter, that improved power factor and efficiency than conventional two-stage power module.

• Journal of Drive and Control
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• v.10 no.1
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• pp.7-13
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• 2013

Port size 80mm or above large-flow type solenoid valves are extensively used in dust collector and power plants. These multi-stage solenoid valve have few problem. first, multi-solenoid valves are almost depend on imports and there are weak in the brine environment and the low energy efficiency. Because these problem, increased the necessity of research on the development of large flow and high pressure type solenoid valves. In this study, describe the design method of multi-stage solenoid test bench and confirm the influence valve performance on several parameter such as diaphragm orifice diameter. At first, each part has modeled by AMESim simulation tool and combining them. This AMESim virtual multi-stage solenoid valve found influence valve performance on the valve parameter. Finally developed the multi-stage solenoid valve and verified that performance on experimental result.

• Health Policy and Management
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• v.18 no.4
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• pp.85-110
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• 2008

In this study, we explore the long-term demand forecasting of high-price medical equipments based on logistic and Bass diffusion model. We analyze the specific pattern of each equipment's diffusion curve by interpreting the parameter estimates of Bass diffusion model. Our findings are as follows. First, ultrasonic imaging system, CT are in the stage of maturity and so, the future demands of them are not too large. Second, medical image processing unit is between growth stage and maturity stage and so, the demand is expected to increase considerably for two or three years. Third, MRI is in the stage of take-off and Mammmography X-ray system is in the stage of maturity but, estimates of the potential number of adopters based on logistic model is considerably different to that based on Bass diffusion model. It means that additional data for these two equipments should be collected and analyzed to obtain the reliable estimates of their demands. Fourth, medical image processing unit have the largest q value. It means that the word-of-mouth effect is important in the diffusion of this equipment. Fifth, for MRI and Ultrasonic system, q/p values have the relatively large value. It means that collective power has an important role in adopting these two equipments.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.13 no.2
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• pp.1-13
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• 2018

This study examines the relationship between the organizational general characteristics (industry, size, location, development stage, and company age) and success factors of Korean venture firms using secondary data. Among the industries with the highest sales figures in 2016 are food / fiber / (non) metals, and the smallest category was software development. The sectors with the highest net profit were computer / semiconductor / electronic components, and the smallest category was telecommunication equipment / broadcasting equipment. The industries with the largest sales growth rate are IT / broadcasting services and software development. The industries with the highest net profit margin of sales are energy / medical / precision, and the smallest is telecommunication equipment / broadcasting equipment. In terms of the number of employees, venture firms with more than 100 employees have the largest sales and net profit, with employees between 1 and 9 have the smallest. However, these results are predictable. In general, the number of employees is highly correlated with sales and net profit. Rather, the sales growth rate and the net profit margin of sales may be meaningful. In particular, with employees between 50 ~ 99, the growth rate of sales and the net profit margin of sales were high. In terms of location, Seoul / Incheon / Gyeonggi were the regions with the highest sales and Daejeon / Sejong / Chungcheong / Gangwon were the least regions. Gwangju / Jeolla / Jeju and Seoul / Incheon / Gyeonggi were almost similar in the areas with the largest net profit. However, Daejeon / Sejong / Chungcheong / Gangwon had the lowest net profit. Unusually, the areas with the highest sales growth rate and the highest net profit margin of sales were Gwangju / Jeolla / Jeju, and the smallest areas were Busan / Jeonnam / Ulsan In the relationship between the stage of development and the performance of the company, the sales of maturity and decline stages were the highest and establishing stage was the lowest. Net profit was also the highest in mature stage and the smallest in establishing stage. The sales growth rate shows a typical pattern in the order of establishing stage, early growth stage, high growth stage, maturity stage, and decline stage. In terms of business performance, sales and net profit are the highest with 21 years or more of company age, and the smallest is less than 3 years. In addition, the sales growth rate was the highest in three years or less, and the net profit margin of sales was the highest in 4 to 10 years. This study can present lots of useful implications by suggesting integrated research model and examining the success factors of Korean venture firms and presenting the application methods of secondary data in analyzing the current status of venture industry in Korea.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.4
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• pp.389-395
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• 2016

Wheel loaders are utilized not only on construction sites, but also for general purposes, such as manufacturing and transportation. Therefore, during the basic design stage of this type of working device equipment, the designer should consider specifications as well as working performance. In this research, a characteristic analysis program was developed for use in the basic design stage of construction equipment using multibody dynamics analysis. In addition, through the optimization of its links, improvements to the lifting capability of a Z-bar-linkage-type wheel loader were suggested. Using the developed program and process, it is possible to reduce the time required for the basic design of the working device.

• Journal of Practical Engineering Education
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• v.6 no.1
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• pp.37-42
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• 2014

The automated visual inspection system (machine vision system) for quality assurance is important factory automation equipment in the manufacturing industries, such as display, semiconductor, etc. There is a lot of demand for the machine vision engineers. However, there are no technical training courses for machine vision technologies in vocational schools, colleges and universities. In this paper, we present the implementation of line scan camera based equipment for technical training of the automated visual inspection system. The training system consists of the X-Y stage which is widely used in machine vision industries and its variable image resolution are set to $10-30{\mu}m$. Additionally, this training system can attach the industrial illumination, either the direct illuminator or coaxial illuminator, for verifying the effect of illuminations. This means that the trainee can have a practical training in various equipment conditions and the training system is similar to the automated visual inspection system in industries.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.201-207
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• 2005

디스플레이 장치를 제조함에 있어 Lithography 공정은 매우 중요한 공정으로 인식되고 있으나 아직까지 Lithography 장비의 국내 기술개발 수준은 선진사에 비해 많이 뒤져있다고 볼 수 있다. 최근 디스플레이 산업의 폭발적인 성장과 더불어 보다 확실하고 안정적인 생산을 위해서는 Lithography 장비의 국산화 기술개발이 시급한 상황이다. 본 연구는 Lithography 장비를 구성하는 핵심기술요소 중 Stage 최적화에 대하여 현재 국내외에서 개발된 또는 개발중인 제품들을 비교 분석하고, 최적화 설계를 위해 필요한 조건들에 대하여 고찰해보았다.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.221-226
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• 2012

In this paper, wideband two-stage amplification stage was designed, fabricated and evaluated. The proposed amplification stage with a novel gain control method have a high gain, low noise and high linearity performance. It is consisted of common emitter amplifier as the first stage, cascode gain control amplifier as second stage and power detector which sense the received signal strength. The proposed amplification stage shows a total gain of 29 dB~37 dB, noise fiugre of 1.5 dB at operating band and high linearity performance as the IMD (third intermodulation distortion) level is below the noise level of the measurement equipment at the control voltage 2.0 V generated from power detector under the strong electric field condition.

• Plant Journal
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• v.16 no.1
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• pp.28-33
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• 2020

This study analyzes the requirements for international standardization by studying the approach to international standardization of equipment and bulk materials in the offshore oil & gas industry, and describes the prioritization of standardized equipment and the result of standardization in the first stage. Currently, international standardization activities can be classified into three activities. First, international standardization activities of bulk materials led by three major domestic shipbuilders, second, JIP33 equipment standardization activities led by IOGP, and finally, And standardization activities of UEJIP equipment centered on classification society. This study classifies various international standards applied in the offshore oil & gas industry, and introduces the activities of standardization activities of class-leading equipment and actual application examples.