• Proceedings of the IEEK Conference
• /
• 2002.07a
• /
• pp.662-665
• /
• 2002

This paper describes a novel converter to implement high-speed binary-to-residue conversion for moduli 2$^{n}$ - 1, 2$^{n}$ , 2$^{n}$ +2$^{\alpha}$/($\alpha$$\in$｛0,1,…,n-1｝) without using look-up table. In our implementation, the high-speed converter can be achieved, because of the modulo addition time is independent of the word length of operands by using the Signed-Digit (SD) adders inside the modulo adders. For a LSI implementation of residue SD number system with ordinary binary system, the proposed binary-to-residue converter is the efficient circuit.cient circuit.

• Proceedings of the IEEK Conference
• /
• 2003.07d
• /
• pp.1475-1478
• /
• 2003

When multimedia contents are adapted to different terminals in the ubiquitous computing environment, the contents' modalities can be converted variously. In this paper, we present an efficient user preference that enable user to specify his choices on the modalities of the adapted contents. We also propose the methods to systematically integrate the user preference into the content adaptation process. This modality conversion preference has been developed as a description tool for MPEG-21 Digital Item Adaptation (DIA).

• 전기의세계
• /
• v.25 no.5
• /
• pp.63-69
• /
• 1976

Among various types of photo-electric energy conversion element which can transfer solar energy into electric energy through the photo voltaic effect, Si solar cells were investigated on photoelectric characteristics, improvements of its efficiency and economical evaluation for its production cost. To study the above subjects, we decided best conditions on fabricating of thin film Si solar cell by epitaxial growth and knew that the thin solar cell by epitaxial growth was more efficient than that by diffusion process. And also higher photo voltaic output was obtained as a effect of SiO as antireflection coating by several methods, i.e. vacuum evaporating techniques of electrode to decrease the contact resistance and to form best ohmic contact, and concentration techniques of sun's ray by lenz or both-sided illumination through special structure for reflection using mirrors.

• Annual Conference on Human and Language Technology
• /
• 1997.10a
• /
• pp.439-445
• /
• 1997

한글 워드프로세서의 한자 사용이 필수적인 요소이다. 일상 생황에서 의사를 전달하기 위해서는 한국어로 사용하지만, 글이나 작문을 이용하여 의사를 전달할 때는 한글이 주를 이루고 문맥 안에 함축된 의미로 한자를 사용하면 정확하게 의사가 전달된다. 현재의 한글 워드프로세서에서는 한자 순위 변환 시스템의 키의 검색 횟수가 많고 또한 복합한자 변환 시스템에서는 실행 횟수가 많은 단점을 가지고 있다. 본 논문에서는 보다 효율적인 키의 검색 횟수를 줄이기 위해 효율적인 한자 순위 변환 알고리즘과 실행횟수를 줄이기 위해 개선된 복합한자 변환 알고리즘을 사용한다. 이러한 알고리즘은 검색과 실행 속도를 빠르게 함은 물론 한글 한자 변환시스템 처리에 도움을 줄 수 있다.

• Journal of Power Electronics
• /
• v.9 no.6
• /
• pp.866-873
• /
• 2009

In general, the output voltage level of a PV array varies widely at various irradiances and temperatures. The MPP (Maximum Power Point) range of a medium- or high-power PV PCS is normally 450~830Vdc or 300~600Vdc. This means the PV PCS should operate in a wide range of modulation indexes. The PV PCS should satisfy the harmonic current requirement that the TDD (Total demand distortion) shall not exceed 5%. This paper proposes a new PWM control method for a medium- or high-power PV PCS which increases the efficiency of power conversion in all operation ranges with acceptable harmonic ripple currents. This paper compares and analyzes appropriate PWM schemes for the PV PCS in the view points of conversion efficiency and current harmonics.

• Proceedings of the KIPE Conference
• /
• 2011.07a
• /
• pp.504-505
• /
• 2011

Decreasing actual greenhouse gas will be difficult if it is not solved addressed in architectural fields. Zero emission building or zero energy building, maximize the efficiency of energy, which means the building can operate by their own renewable energy facility without any other supplying. To be a zero emission building, a building needs realization of high efficiency low energy consumption, construction of building its own energy production facilities and lastly a power grid connection. According to increasing of DC load about TV, LED lighting, computer, IT in building for living and business, it is expected the save of energy when the system of AC power distribution change into the system of DC power distribution. Renewable energy exists a big different rate produced by outside environment. When electrical power overproduce, it can supply for system. Otherwise, if electrical power produce less, it can receive supply from system. Send and receive power can lead to zero to annual standard. This paper shows the simulation about efficient control of power conversion which is related to DC power distribution of architecture and DC output of renewable energy by using L-type converter.

• Korean Management Science Review
• /
• v.30 no.3
• /
• pp.55-70
• /
• 2013

In this study we suggested two optimization models to determine conversion weight of convertible bonds. The problem of this study is same as that of Park and Shim [1]. But this study used Value-at-Risk (VaR) for risk measurement instead of CVaR, Conditional-Value-at-Risk. In comparison with conventional Markowitz portfolio models, which use the variance of return, our models used VaR. In 1996, Basel Committee on Banking Supervision recommended VaR for portfolio risk measurement. But there are difficulties in solving optimization models including VaR. Benati and Rizzi [5] proved NP-hardness of general portfolio optimization problems including VaR. We adopted their approach. But we developed efficient algorithms with time complexity O(nlogn) or less for our models. We applied examples of our models to the convertible bond issued by a semiconductor company Hynix.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1996.04a
• /
• pp.100-103
• /
• 1996

Presented in this study is an algorithmic procedure to obtain polyhedral model from a compound surface. The compound surface in this study denotes a collection of trimmed surfaces without topological relations. The procedure consists of two main modules: CAD data interface, and surface conversion to polyhedral model. The interface module gets geometric information from CAD databases, and makes topological information by scanning the geometric information. We are investigating CATIA system as a data source system. In the surface conversion module, a shell(compound surface with topological information) is approximated to a triangular-faceted polyhedral surface model through node sampling and triangulation steps. The obtained polyhedral model should obey the vertex-to-vertex rule and meet tolerance requirements. Since the polyhedral model has a simple data structure and geometry processing for it is very efficient and robust, the polyhedral model can be used in various applications, such as surface rendering in computer graphics, FEM model for engineering analysis, CAPP for surface machining, data generation for SLA, and NC tool path generation.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.10
• /
• pp.1757-1762
• /
• 2007

Recently, the demand for the low cost power conversion equipment is rapidly increased. To develop this three phase voltage source inverter, optimum power conversion equipment to system is designed. The optimum operation method to minimize the power loss also satisfy the life time of the power electronics that is request in the present industry. In this paper, the efficient operating method to change of the acceleration, jerk, and switching frequency in the interval of acceleration is selected to optimize the power loss and life time of the power electronics by using the elevator model. So, we proposed the method that 50[A] rating power electronics is adopted in 9[kW] load.

• Journal of the Korean Applied Science and Technology
• /
• v.17 no.1
• /
• pp.15-21
• /
• 2000

The catalytic hydroxylation of several cycloalkanes in dichloromethane have been investigated using In(Ⅲ)-, Tl(Ⅲ)-porphyrin complexes as a catalyst and NaClO, $NaClO_{2}$, $H_{2}O_{2}$ as a terminal oxidant. Porphyrins were TPP and ($F_{20}$)TPP (TPP = tetraphenylporphyrin) and substrates were cyclopentane, cyclohexane, cycloheptane and cyclooctane. The substrate conversion yield was discussed according to the substituent effect and hinderance effect of metalloporphyrin and the radius effect of non-redox metal ion. The conversion yield of cycloalkane followed the order of $ C_{5} $ < $ C_{6}$ < $ C_{7}$ = $ C_{8}$. In this experimental condition $NaClO_2$ was rather efficient terminal oxidant than NaClO and $H_{2}O_{2}$.