• 한국환경보건학회지
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• 제32권5호
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• pp.469-477
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• 2006

When denitrification was connected with a single stream process by using biofilter and sulfur-limestone, it was found that such connection enabled highly efficient nitrification without special unit operation of microorganisms or injection of external carbon sources which is being shown in general biological treatment processes. It was observed that in the trickling filter bed, decomposition of organic substances and highly efficient nitrification by both the forced pressure feed trickling and the air fan were simultaneously done. In the denitrification tank where sulfur-limestone was mixed at a certain ratio, limestone was used by autotrophic microorganisms as a source of supply for alkalinity, and nitrate $NO_{3}^{-}$-N was denitrified into nitrogen gas. And in the sulfur-limestone autotrophic denitrification, $NO_{3}^{-}-N\;or\;NO_{2}^{-}-N$ was denitrified as a sulfur compound in reduction state was oxidized into a final output of $SO_{4}^{-2}$. The mean concentration of the discharge water was 8.6 mg/l for T-N and 0.8 mg/l for T-P, respectively, and their mean treatment efficiency was 79.2% and 80.8%, respectively. Implementing highly efficient denitrification without injection of an external organic carbon source or internal return, it is concluded that the proposed process is suitable for a sewerage in a small village with the merits of low power consumption and easy maintenance.

• Journal of electromagnetic engineering and science
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• 제11권3호
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• pp.143-151
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• 2011

This paper presents a survey of recent wireless power transfer systems. The issue of wireless power transfer is to achieve a highly efficient system with small positioning errors of the facilities setting. Several theories have been presented to obtain precise system design. This paper presents a summary of design theory for short range power transfer systems and detailed formulations based on a circuit model and an array of infinitesimal dipoles. In addition to these theories, this paper introduces a coil array scheme for improving the efficiency for off axis coils. In the microwave range, tightly coupled resonators provide a highly efficient power transfer system. This paper present san-overlay resonator array consisting of half wavelength microstrip line resonators on the substrate with electromagnetically coupled parasitic elements placed above the bottom resonators. The tight couplings between the waveguide and the load resonator give strong power transmission and achieve a highly efficient system, and enables a contact-less power transfer railroad. Its basic theory and a demonstration of a toy vehicle operating with this system are presented. In the last topic of this paper, harmonic suppression from the rectenna is discussed with respect to acircular microstrip antenna with slits and stubs.

• 융합보안논문지
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• 제5권1호
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• pp.85-92
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• 2005

고도로 분산된 컴퓨팅 환경에서 역할 기반 접근제어를 함에 있어서 속성 인증서를 사용한 역할의 효율적 관리 방법을 모색하고자 한다. 역할은 그룹화되며, 속성인증서를 통해 관리된다. 유비쿼터스 컴퓨팅 환경과 같은 고도의 분산 컴퓨팅 환경에서는 광범위한 통제 구조를 가질 수 없으므로 이를 고려한 속성 인증서 관리 기법으로 속성 인증서의 전송 방법, 그룹 키의 관리 방법 등이 고려되어야한다. 본 논문에서는 네트워크 상의 효율적 속성 인증서 관리 기법을 모색하며, 그의 기반이 되는 역할의 그룹화를 논한다. 역할을 그룹화하여 관계구조 트리를 구성하고, 분산된 환경에서 안전하고 효율적인 역할의 갱신과 분배를 달성한다. 규모 확장성을 위해 멀티 캐스팅 패킷을 사용한 속성 인증서 분배를 하며, 그에 따른 네트워크 상의 패킷 손실율을 고려한 성능분석을 하여 역할 그룹을 두어 속성 인증서를 구조화하는 것이 성능을 향상시킴을 정량적으로 보인다.

• 한국전자파학회논문지
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• 제23권5호
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• pp.606-612
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• 2012

W-CDMA 단말기에 적용 가능한 고효율 다중 모드 balanced 전력증폭기 구조를 제안하였다. 제안된 전력증폭기는 2단 증폭기로 구성되었고, 낮은 전력 영역 및 중간 전력 영역에서 효율을 증가시키기 위해 stage-bypass 기법과 부하 임피던스 스위칭 기법이 적용되었다. 이를 통해 4가지의 고효율 전력 모드를 구현하였으며, 제안된 구조를 실험적으로 검증하기 위해 GaAs HBT 전력증폭기를 설계 및 제작하였고, 측정하였다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.291-294
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• 2007

Countries in the world are setting up policies to implement anti-global warning measures to actively cope with the Agreement on Climate Change. Rising problems related to energy and environment prompted research and development efforts to highly efficient electric instrument and environmentally friendly products to secure resources and save energy Korea's high dependency on imported energy and its lack in natural resources make it urgently necessary to develop energy efficient instrument and equipment that can save energy. Every household now uses a transformer, which is very important instrument among others. A variety of technologies to manufacture transformers are currently used along with efforts to develop new materials. Development nit of high efficient transformers is called for by the time and has direct economic impact on suppliers and consumers. In addition, it is desirable to install a transformer that is trustworthy, secure, low on loss, anti-incident capable, small, anti-flammable, environmentally friendly, cost-efficient high-frequency resistant and easy for maintenance. To do this, it is necessary to look deeper into a highly efficient transformer that can save energy. This paper will discuss the types and characteristics of various transformers and propose ways to save energy and raise efficiency tv analyzing a environmentally friendly amorphous transformer.

• Journal of the Korean Statistical Society
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• 제35권4호
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• pp.441-452
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• 2006

Here an efficient regression type estimator for a stratified population mean is proposed under the two-phase sampling scheme. While constructing the proposed estimator, it is assumed that the first auxiliary variable x is directly and highly correlated with the study variable y, and the second auxiliary variable z is directly and highly correlated with the first auxiliary variable x. However the variable z is not directly correlated with the variable y, but they are just correlated with each other only due to their direct and high correlation with the variable x. The proposed regression type estimator is found to be always more efficient than the existing estimators defined under the same situation.

• Journal of Information Display
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• 제9권4호
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• pp.11-14
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• 2008

A highly efficient organic light-emitting diode (OLED) with an in-cell polarizer made of an imprinted liquid crystalline polymer (LCP) layer doped with dichroic dye molecules is presented. The in-cell polarizer was found to be capable of effectively polarizing the emission light of the OLED and of significantly improving the luminance through the periodic microstructures fabricated using an imprinting method. This type of OLED with an imprinted in-cell polarizer is useful for efficient light source applications in liquid crystal displays (LCDs).

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1516-1519
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• 2008

We report extremely low doping technology in phosphorescent organic light emitting diodes(PHOLEDs). Highly efficient red PHOLEDs with excellent energy transfer characteristics even under 1 % doping condition have been demonstrated. Results reveal efficient host-dopant system to realize highly efficient PHOLEDs and useful cost saving way by reduction of expensive Ir complex dopants.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.803-805
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• 2009

A highly efficient blue organic light-emitting diode (OLED) was fabricated by using a novel polymer host, poly[3-(carbazol-9-ylmethyl)-3-methyloxetane]. The resultant solution-processed device showed a markedly high efficiency of 29.7 lm/W at 100 cd/$m^2$ by doping 24 wt% blue dye bis(3,5-difluoro-2-(2-pyridyl)-phenyl-(2-carboxy pyridyl) iridium (III).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2886-2891
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• 2008

The purpose of this study is to develop a highly-efficient and compact steam reformer for PEMFC changing the burner types. For the purpose some of the Can type flat burners were adopted and the results were compared with 'O' company's typical cylinderical flat burner. We used commercial STAR-CD tools for numerical calculation. We found the optimum Can type STR burner and this type of burner was highly efficient comparing with typical burner.