• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제7권10호
• /
• pp.2479-2496
• /
• 2013

Increasing demand for Full High-Definition (FHD) video and Ultra High-Definition (UHD) video services has led to active research on high speed video processing. Widespread deployment of multi-core systems has accelerated studies on high resolution video processing based on parallelization of multimedia software. Even if parallelization of a specific decoding step may improve decoding performance partially, such partial parallelization may not result in sufficient performance improvement. Particularly, entropy decoding has often been considered separately from other decoding steps since the entropy decoding step could not be parallelized easily. In this paper, we propose a parallelization technique called Integrated Multi-Threaded Parallelization (IMTP) which takes parallelization of the entropy decoding step, with other decoding steps, into consideration in an integrated fashion. We used the Simultaneous Multi-Threading (SMT) technique with appropriate thread scheduling techniques to achieve the best performance for the entire decoding step. The speedup of the proposed IMTP method is up to 3.35 times faster with respect to the entire decoding time over a conventional decoding technique for H.264/AVC videos.

• 전력전자학회논문지
• /
• 제17권6호
• /
• pp.500-506
• /
• 2012

In this paper, a non-isolated high step-up and high efficiency boost converter is proposed. By using the 3-level boost converter structure, the proposed converter can obtain higher voltage gain than conventional high step-up converters. The voltage spike of the switching device is well clamped by using the clamp circuit composed of a clamp diode and a capacitor and the energy of the leakage inductor of coupled inductor is effectively transferred to output. Due to the 3-level structure, the equivalent switching frequency of the coupled inductor is doubled, which results in reduced inductor size. A 500 W prototype converter is built and tested to verify performance of the proposed converter.

• Journal of Power Electronics
• /
• 제18권1호
• /
• pp.11-22
• /
• 2018

This paper presents a single switch, high step-up, non-isolated dc-dc converter suitable for renewable energy applications. The proposed converter is composed of a coupled inductor, a passive clamp circuit, a switched capacitor and voltage lift circuits. The passive clamp recovers the leakage inductance energy of the coupled inductor and limits the voltage spike on the switch. The configuration of the passive clamp and switched capacitor circuit increases the voltage gain. A wide continuous conduction mode (CCM) operation range, a low turn ratio for the coupled inductor, low voltage stress on the switch, switch turn on under almost zero current switching (ZCS), low voltage stress on the diodes, leakage inductance energy recovery, high efficiency and a high voltage gain without a large duty cycle are the benefits of this converter. The steady state operation of the converter in the continuous conduction mode (CCM) and discontinuous conduction mode (DCM) is discussed and analyzed. A 200W prototype converter with a 28V input and a 380V output voltage is implemented and tested to verify the theoretical analysis.

• 전력전자학회논문지
• /
• 제3권2호
• /
• pp.131-137
• /
• 1998

태양전지의 출력특성은 일사량, 온도와 부하에 의해 크게 변동하기 때문에 가능한 한 많은 에너지를 얻기 위해서는 태양전지의 출력을 항상 최대로 제어할 필요가 있다. 또한 가정용 부하는 교류부하인 반면에 태양전지의 출력은 직류이므로 태양광 발전 시스템에서는 인버터가 필수적이며, 단위역률을 갖는 정현파 전류 및 전압을 계통에 공급해 주어야 한다. 본 논문에서는 계통연계형 태양광 발전시스템을 승압쵸퍼와 전압형 인버터로 구성하였다. 전력비교에 따른 시비율을 변화시켜 일사량과 온도변화에 관계없이 항상 최대출력점을 추적하도록 승압쵸퍼를 제어하였고, 전압형 인버터는 위상동기를 위해서 계통전압을 검출하여 계통전압과 인버터 출력을 동상 운전하므로 고역률과 저고조파 출력으로 부하와 계통에 전력이 공급되도록 제어하였다.

• 전력전자학회논문지
• /
• 제6권5호
• /
• pp.400-409
• /
• 2001

대용량 승압형 응용을 위한 새로운 위상천이 병렬입력/직렬출력 듀얼 컨버터가 제안된 바 있다. 제안된 컨버터는 종래의 펄스 폭 변조(PWM) 방식의 병렬입력/직렬출력 듀얼 컨버터에 비해 낮은 스위치 전압 스트레스를 보여 저 손실의 소자를 사용할 수 있으므로 높은 효율을 보인다. 또한, 출력 캐패시터의 실효(RMS) 전류 스트레스가 낮고 입력 전류와 출력 전압의 맥동이 작으며, 제어 입력에 대한 출력 전압의 동역학(dynamics)이 빠른 장점이 있다. 본 논문에서는 제안된 컨버터의 정상상태 동작을 심도 있게 분석하고 그 수학적 모델 및 정상상태 해를 제시하며, 제안된 컨버터의 특징을 종래의 PWM 방식의 컨버터와의 비교를 통해 정량적으로 분석한다. 또한, 제안된 회로의 동작, 특성 및 유효성을 검증하기 위해 800W급 24-350Vdc 사양의 시작품으로부터의 실험 결과를 제시한다.

• 대한한의학방제학회지
• /
• 제30권4호
• /
• pp.281-291
• /
• 2022

Objectives : In this study, acute oral toxicity test of pomace Schisandra chinensis extracts was conducted in order to up-cycling to a high value-added industry using by-products discarded in the production process of Schisandra chinensis products and active ingredients such as dibenzocyclooctadiene lignans in Schisandra chinensis. Methods : Pomace Schisandra chinensis extracts were orally administered to SD-rats(female, n=3) without a control group according to the 'OECD guidelines'. After, mortality and clinical signs were observed, and the deceased animals were subjected to an autopsy. In addition, acute oral toxicity test was sequentially performed in step I (300 mg/kg), step II(300 mg/kg), step III(2,000 mg/kg), and step IV(2,000 mg/kg) according to the mortality. Results : There were no abnormalities caused by pomace Schisandra chinensis extracts in step I and step II. However, one animal each died in step III and step IV. In addition, clinical signs(salivation, decrease in food intake, prone position, decrease of locomotor activity, loss of locomotor activity, convulsion, hypothermia, lacrimation, staining around mouth, soiled perineal region, reddish urine, chromaturia, decrease of fecal volume, lying on side, blackish stool, no stool, compound-colored stool, refusal to feed, excitement, hypersensitivity, rigidity, dorsal position, etc.) were observed. But, no clinical signs were observed from 5th day, and experiment animals recovered completely. Conclusions : As a result of this study, pomace Schisandra chinensis extracts may exhibit acute toxicity at concentrations of 2,000 to 5,000 mg/kg, and the GHS classification was designated as 'Category 5'.

• Journal of Power Electronics
• /
• 제18권2호
• /
• pp.343-355
• /
• 2018

A wide-voltage-conversion range bidirectional DC-DC converter is proposed in this paper. The topology is comprised of one typical LC energy storage component and a special common grounded asymmetric H-bridge with four active power switches/anti-parallel diodes. The narrow output PWM voltage is generated from the voltage difference between two normal (wider) output PWM voltages from the asymmetric H-bridge with duty cycles close to 0.5. The equivalent switching frequency of the output PWM voltage is double the actual switching frequency, and a wide step-down/step-up ratio range is achieved. A 300W prototype has been constructed to validate the feasibility and effectiveness of the proposed bidirectional converter between the variable low voltage side (24V~48V) and the constant high voltage side (200V). The slave active power switches allow ZVS turn-on and turn-off without requiring any extra hardware. The maximum conversion efficiency is 94.7% in the step-down mode and 93.5% in the step-up mode. Therefore, the proposed bidirectional topology with a common ground is suitable for energy storage systems such as renewable power generation systems and electric vehicles with a hybrid energy source.

• 한국가정과교육학회지
• /
• 제2권1호
• /
• pp.123-142
• /
• 1990

The aim of this study is to apply lesson design of high school home economics to model which consists of six steps of instructional procedure among various models for instructional design, Through thesis, central content of each step was written as follows; 1) At the step of establishment of terminal instructional objectives, educational objectives, terminal instructional objectives was analyzed and specific instructional objectives was extracted. 3) At the step of diagnosis of entering behavior, ability of prior learning and ability of preliminary learning were evaluated, which was used as establishing instructional strategy and doing individual guidance. 4)At the step of determining instructional strategy, instructional strategy should be extracted by considering instructional event which is adequate to content of instruction. Instructional strategy consists of five main factor, factors, those are, activity of introduction of instruction, presentation of content of instruction and information, participation of learner and learning activity, identification of learning result, and subsequent treatment after evaluation. 5)Specific activity at the step of selection and development of instructional media consists of reidentification of instructional objectives determination of learning type, drawing up instructional media analysis sheet, synthesis of selected media, and explanatory note of selected media. In order to increase efficiency of instruction at the step of determining instructional strategy, this step should be considered simultaneously. 6)The step of try-out and evaluation of instructional design should be efficient when designed instruction was inputted at class after evaluation of each step of instructional design.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.3-11
• /
• 2002

This paper presents the trend of low voltage and high current technology for DC-DC converters. It can be said that the output voltage of the on-board power supply has been rapidly moving forward a low voltage in proportion to the minuteness of the semiconductors. As for as its speed is concerned, the change of the market situation seems to be faster than that of R&D for the low voltage and high current products put out by power supply manufacturers. Here, the present situation and the trend of non-isolated type step-down DC-DC converter and isolated type DC-DC converter called "Brick" will be taken up mainly from the fellowing point of view. -low voltage and high current keeping up with the current demand for the latest telecommunication networks and broadband. -build-up of the total solution for dispersion system power supply. In this paper, an explanation is given to mainly concerning to the newest products in the supplier's position.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2011년도 전력전자학술대회
• /
• pp.340-341
• /
• 2011

본 논문에서는 높은 승 강압비를 갖는 양방향 DC-DC 컨버터에 대한 최적의 스위칭 기법을 제안한다. 제안한 컨버터는 CCM에서도 소프트 스위칭이 가능하여 스위칭 손실뿐만 아니라 인덕터의 발열도 줄일 수 있다. 또한 모든 소자의 전압 정격과 수동소자의 부피도 기존 양방향 컨버터 보다 작아 고효율 및 고전력밀도의 달성을 기대 할 수 있다. 1.5kW 시작품의 실험을 통해 본 논문의 타당성을 검증하였다.