• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.191-194
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• 2003

Through using aspheric lens can result in advantages such as an improved optical transfer function, a reduced distortion path or the realization of special image field curvatures. Using the diamond turning method for generating aspherics, the company claim to be able to generate surfaces with a form error of less than $0.33\;{\mu}\;m$ and a surface roughness of less than $0.025\;{\mu}\;m$. In this paper, we are manufacturing thermal image aspheric lens. Thermal image system is electro-optical imaging device which can make visible the difference of infrared energy naturally emitted by objected. In the result of aspherical surface, the form accuracy of about $0.24\;{\mu}\;m$ P-V was obtained and the surface roughness Ra $0.004\;{\mu}\;m$. Also, a brief review of Ultra-precision system Korea photonics technology institute(KOPTI) is present in this paper.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.2
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• pp.112-121
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• 2008

Nowaday the supply chain competitiveness is emphasized more and more than a company's own competitiveness. One of the most important processes in import and export is a publication over the Bill of Loading. In the publication of those bills S/R(shipping request) and check B/L for reviewing are circulated among consignors, forwarders, shipping companies and airlines by fax and e-mail. Or there should be expensive a One to One system, like an EDI. Each party has to re-input S/R data to their own systems and check it several times. The S/R data are converted digital to analog type and analog to digital repeatedly to check in the process. As the process goes by there can be not only input data errors but also waste of time and cost. ECR(electronic character recognition) is a technology can solve the Problem. Considering the data structure of documents in many systems used ECR samples SIR data from documents written in the digital type. But it is not enough with it only. To make N to N composition in reality more efficient we make a documents hub on the web reengineering the existing process to One to One relation. The ECR documents hub system has given us beneficial effects over a year throughout a field test.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.6
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• pp.333-339
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• 2009

The objective of this study is to predict optimal intermediate pressure of a 2-stage compression heat pump system using river water. To determine the maximum performance of the 2-stage compression heat pump system, the experimental evaluations on the 2-stage compression cycle were carried out under various operating conditions. Electronic expansion valves were applied to control intermediate pressure and superheat. Based on the experimental data, an empirical correlation for predicting optimal intermediate pressure which considering cycle operating parameters was developed. The present correlation was verified by comparing the predicted data with the measured data. The predictions showed a good agreement with the measured data within a relative deviation of ${\pm}4%$ at various operating conditions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.9-15
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• 2013

In this paper, automatic recognition of an accident and whether service delivery and risk driving through the giving of the driver to correct driving habits before and after the accident to reproduce highly scalable video Smart Mobile Blackbox DVR (SMBD, Smart Mobile Blackbox DVR) Computer of the model was designed. SMBD on embedded systems equipped with wireless capabilities to sleep in the car accident point and the image information by wireless communications, by notification in the control center, 24-hour emergency rescue service and traffic information can be provided. The vehicle ECU (Electronic Control Unit) of the vehicle information and sensor data in conjunction with wireless eCall (Emergency Call) services can be realized.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.868-874
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• 2010

In this paper, we propose a design of automated electronic sanction system for management of six sigma projects. The proposed system performs diverse operations such as registering and choosing enterprise-wide enhancement project, managing schedules of the project, verifying the validity of the project, and thus managing the whole life cycle of the project. Each six sigma project is stored in the database repository for facilitation of its later use. The proposed system has been effectively applied in a Korean company, and thus, through the proposed system, we expect the effects of innovation-related and enhancement-related activities which six sigma is fundamentally pursuing.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.193-193
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• 2008

In this paper, a MMIC diplexer with a low pass and high pass filter are designed and fabricated using an InGaP/GaAs process. The design of this diplexer is based on its stabilization of the low insertion loss since it is important in the in-building system (IBS). The IBS integrates wire and wireless signal between the cable television (CATV) and the personal communication system. In this design, a dual-mode operation of diplexer is fabricated with the frequency of 0 Hz to 900 MHz and 1.7 GHz to 2.2 GHz for CATV and personal communication. respectively. The topolygy of the designed diplexer is based on the L-C filter. This diplexer fabricated by nanoENS Inc. which is foundry service company, was measured by using the facilities of the Kwangwoon University RFIC center. The fabricated chip size is $1.6\times1.4mm^2$ and it has abroad frequency range from 0 Hz to 2.2 GHz.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.194-194
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• 2008

Boron doped ZnO:Al(AZOB) thin films were prepared on glass substrates by dc magnetron sputtering. Influence of the annealing treatment on the electrical and optical properties of AZOB thin films were investigated. The lowest resistivity of $1.6\times10^{-3}\Omega$-cm was obtained at an annealing temperature of $400^{\circ}C$. The average transmittance of the films is over 80% in the visible range. It was also shown that by introducing boron impurity into AZO system improve the uniformity, the resistivity, and thermal stability of ZnO-based conducting thin films.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.1
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• pp.27-33
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• 2012

Internet Data Centers (IDC), as essential facilities for modern IT industry, typically have scores of MW of concentrated electric loads. Uninterruptible Power Supplies (UPS) are necessary for the power feed system of IDCs because of stable power requirement. Thus, conventional AC power feed systems of IDCs have three cascaded power conversion stages such as (AC-DC), (DC-AC), and (AC-DC), which results in very low conversion efficiency. On the contrary, DC power feed systems need just a single power conversion stage (AC-DC) supplying AC mains power to DC server loads, which gives comparatively high conversion efficiency and reliability. This paper compares the efficiencies between 220V AC power feed system and 300V DC power feed system on equal load conditions which were established in Mok-Dong IDC of Korea Telecom company (KT). Experimental results show that the total operation efficiency of the 300V DC power feed system is around 15% higher than that of the 220V AC power feed system.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.11
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• pp.1725-1732
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• 2013

This paper deals with an approach to boost the public sector SI market in Korea. In order to promote competition powers of the software industry in Korea, a software industry promotion law has been issued, which restricts large SI companies from competing in the public sector system integration market. However, naturally many SI projects in public sectors are too large and complicated to be carried by small and medium size companies. This paper proposes an approach to reform the SI market for those small and medium size SI companies.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1450-1458
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• 2018

Commutation failures can deteriorate the availability of high-voltage direct current (HVDC) links and may lead to outage of the HVDC system. Most commutation failures are caused by voltage reduction due to ac system faults on inverter side. The commutation failure process can be divided into two stages. The first stage, from the occurrence to the clearing of faults, is called 'Deterioration Stage'. The second stage, from the faults clearing to restoring the power system stability, is called 'Recovery Stage'. Based on the analysis of the commutation failure process, this paper proposes a direct-current fuzzy controller including prevention and recovery controller. The prevention controller reduces the direct current to prevent Commutation failures in the 'Deterioration Stage' according to the variation of ac voltage. The recovery controller magnifies the direct current to speed up the recovery of power system in the 'Recovery Stage', based on the recovery of direct voltage. The validity of this proposed fuzzy controller is further proved by simulation with CIGRE HVDC benchmark model in PSCAD/EMTDC. The results show the commutation failures can be mitigated by the proposed direct-current fuzzy controller.