• Title/Summary/Keyword: 510(k)

Search Result 1,196, Processing Time 0.036 seconds

3-레벨 T-type 인버터에 적용 가능한 저가형 게이트 드라이버 설계 (A Low Cost Gate Drive Circuit Design Based on Bootstrap Circuit for 3-level T-type Inverter)

  • 정준형;김동빈;박상우;염한범;김장목
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2014년도 전력전자학술대회 논문집
    • /
    • pp.510-511
    • /
    • 2014
  • 본 논문에서는 3-레벨 T-type 인버터에 적용 가능한 저가형 게이트 드라이버 회로를 설계하였다. 게이트 드라이버 회로는 구조가 간단하고 가격 대비 효율적인 부트스트랩 회로가 적용되었다. 3-레벨 NPC 인버터와 비교했을때 T-type 인버터는 구조적 특징으로 인해 NPC 인버터와는 다른 게이트 드라이브 회로가 필요하다. 그러므로 본 논문에서는 T-type 인버터에 적용되는 부트스트랩 게이트 드라이버 회로를 설계하였으며 안정적인 회로 동작을 위한 부트스트랩 캐패시터의 용량 선정식을 제안하였다. 설계한 게이트 드라이버 회로는 시뮬레이션을 통해 검증하였다.

  • PDF

초등학생들의 기호식품 선호도 등에 대한 조사연구 (A research study of school children's preferences for insanitary food near school)

  • 조현식;김원식;김양수;최선미;추현민
    • 대한위생학회:학술대회논문집
    • /
    • 대한위생학회 2005년도 정기학술심포지움
    • /
    • pp.50-63
    • /
    • 2005
  • Cheap, low quality food products that are unhealthy are prevailing among children. These low quality products are stirring up the urge to purchase among children and so it is pointed out as a problem. In order to arrive at a solution for the indication of negligence on the side of manufacturing, processing, circulation, and marketing management, a survey asking about interests and preferences on insanitary food products was held during May 2, 2005 to June 30. The subjects were 540 students and 510 parents form 5 elementary schools located at Gwangjin Gu, Seoul including Ja-yang elementary school, etc. This study aims at arranging measures against insanitary food products and contribution to maintenance of children's health.

  • PDF

Acute Hepatic Failure Induced by Xylitol Toxicosis in Two Dogs

  • Lim, Chae-Young;Yoo, Jong-Hyun;Kim, Chun-Geun;Park, Chul;Park, Hee-Myung
    • 한국임상수의학회지
    • /
    • 제25권6호
    • /
    • pp.510-513
    • /
    • 2008
  • Two dogs were referred due to vomiting, depression and anorexia after ingestion of xylitol gum. Both dogs were presented with hepatic failure and one dog had concurrent renal failure. Aggressive supportive treatment was performed, but these dogs died. Necropsy of one dog revealed acute hepatic necrosis, severe renal damages, and hemoperitoneum. This case report demonstrates potential hazard of xylitol toxicity for dogs with clinicopathological and pathological findings.

Nonlinear Acoustic-Pressure Responses of Oxygen Droplet Flames Burning in Gaseous Hydrogen

  • Chung, Suk-Ho;Kim, Hong-Jip;Sohn, Chae-Hoon;Kim, Jong-Soo
    • Journal of Mechanical Science and Technology
    • /
    • 제15권4호
    • /
    • pp.510-521
    • /
    • 2001
  • A nonlinear acoustic instability of subcritical liquid-oxygen droplet flames burning in gaseous hydrogen environment are investigated numerically. Emphases are focused on the effects of finite-rate kinetics by employing a detailed hydrogen-oxygen chemistry and of the phase change of liquid oxygen. Results show that if nonlinear harmonic pressure oscillations are imposed, larger flame responses occur during the period that the pressure passes its temporal minimum, at which point flames are closer to extinction condition. Consequently, the flame response function, normalized during one cycle of pressure oscillation, increases nonlinearly with the amplitude of pressure perturbation. This nonlinear response behavior can be explained as a possible mechanism to produce the threshold phenomena for acoustic instability, often observed during rocket-engine tests.

  • PDF

System Generator를 이용한 SRF-PLL 설계 및 FPGA구현 (Design of SRF-PLL and FPGA Implementation using System Generator)

  • 배형진;조종민;안현성;차한주
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2016년도 전력전자학술대회 논문집
    • /
    • pp.509-510
    • /
    • 2016
  • 본 논문은 계통연계형 인버터의 위상추종기법인 SRF-PLL을 모델링하고, FPGA에 구현하기 위해 System Generator를 이용하여 설계하였다. SRF-PLL의 비례-적분 이득은 소신호 해석을 하여 일반화를 통해 입력전압의 크기에 관계없이 적용가능하며, 주파수 응답에서 65도 위상여유를 갖는 안정한 이득을 산정하였다. FPGA 구현을 위해 MATLAB/SIMULINK와 연동 가능한 System Generator를 이용하여 SRF-PLL을 모델링하였으며, MATLAB 기반의 시뮬레이션과 실험을 통하여 위상추종 특성을 분석하였다.

  • PDF

회전자저항동정을 갖는 유도전동기의 속도센서리스 벡터제어 (Speed Sensorless Vector Control of Induction Motors with the Identification of Rotor Resistance)

  • 김상욱;최세완;김영조;김영석
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1996년도 하계학술대회 논문집 A
    • /
    • pp.510-513
    • /
    • 1996
  • This paper consists of the speed sensorless vector control of induction motors with the estimation of rotor resistance. In the application of variable-speed induction motor drives, if an inaccurate rotor resistance is used because the rotor resistance can change due to skin effects and temperature variables, it is difficult to achieve a collect field orientation. In this paper, to overcome these difficulties adaptive algorithm is designed for rotor resistance identification at the beginning of the transient state. And an adaptive flux observer is used for the purpose of estimating rotor flux and speed in the speed sensorless scheme. Computer simulations are carried out to verity the validity of the proposed algorithm.

  • PDF

Development of a Genistein-enriched Doenjang Using Corn $\beta$-Glucosidase

  • Oh, Jee-Hwan;Suh, Joo-Won;Kim, Jin-Yong;Lee, In-Hyung
    • Food Science and Biotechnology
    • /
    • 제17권5호
    • /
    • pp.1021-1024
    • /
    • 2008
  • Genistein, one of the isoflavones in doenjang, is generally known to prevent various cancers, osteoporosis, climacterium, and menopause symptoms, and has better bioavailability and healthful physiological effects than its glucoside, genistin. In both traditional and commercial doenjangs, genistein content ranged from 370 to 1,510 mg/kg, however, significant amounts of genistin also existed at the level of 190 to 350 mg/kg. After treating with corn $\beta$-glucosidase, over 84% of genistin in doenjang was converted to genistein. However, physiochemical characteristics such as pH, viscosity, 2-thiobarbituric acid (TBA) value, and color were not changed significantly after corn $\beta$-glucosidase treatments. Therefore, this study shows that the improved doenjang with the increased genistein content can be produced using corn $\beta$-glucosidase.

An Adaptive Energy-Efficient and Low-Latency MAC Protocol for Wireless Sensor Networks

  • Liu, Hao;Yao, Guoliang;Wu, Jianhui;Shi, Longxing
    • Journal of Communications and Networks
    • /
    • 제12권5호
    • /
    • pp.510-517
    • /
    • 2010
  • In this paper, an adaptive MAC protocol (variable load adaptive (VLA)-MAC) is proposed for wireless sensor networks. This protocol can achieve high energy efficiency and provide low latency under variable-traffic-load conditions. In the case of VLA-MAC, traffic load is measured online and used for adaptive adjustment. Sensor nodes transmit packets in bursts under high load conditions to alleviate packet accumulation and reduce latency. This also removes unnecessary listen action and decreases energy consumption in low load conditions. Simulation results show that the energy efficiency, latency, and throughput achieved by VLA-MAC are higher than those achieved by some traditional approaches.

모바일 단말기에서 멀티미디어 콘텐츠를 위한 상황인식 사용제어 모델 (Context-aware Usage Control Model for Contents on Mobile Devices)

  • 노진욱;오현수;장혜영;조성제
    • 한국정보과학회:학술대회논문집
    • /
    • 한국정보과학회 2006년도 가을 학술발표논문집 Vol.33 No.2 (C)
    • /
    • pp.507-510
    • /
    • 2006
  • 본 논문에서는 모바일 DRM(Digital Rights Management) 상의 멀티미디어 파일에 적용할 수 있는 상황인식 기반의 사용제어 모델을 제안한다. 특히, 위치 및 시간 등의 상황 정보에 기반하여 모바일 콘텐츠에 대한 접근 및 사용을 제어하는 '동적인 역할기반 접근제어'(dynamic role-based access control)를 지원하는 프로토타입 시스템을 임베디드 보드 상에서 구현하여 테스트하였다.

  • PDF

타원 곡선 암호 기반의 프라이버시와 완전한 전방향 안전성을 제공하는 UMTS-AKA 프로토콜 (ECC-based UMTS-AKA Protocol Providing Privacy and Perfect Forward Secrecy)

  • 김대영;최용강;김상진;오희국
    • 한국정보보호학회:학술대회논문집
    • /
    • 한국정보보호학회 2006년도 하계학술대회
    • /
    • pp.506-510
    • /
    • 2006
  • 3G 이동통신기술중 하나인 UMTS(Universal Mobile Telecommunications System)에서는 무선 구간의 안전한 통신을 위해 UMTS-AKA(Authentication and Key Agreement) 프로토콜이 사용된다. 그러나 SN(Serving Network)과 HN(Home Network)의 통신량 소비 문제, SQN(SeQuence Number) 동기화 문제 등 여러 가지 문제점이 제기되었다. 본 논문에서는 기존 프로토콜의 문제점과 IMSI(International Mobile Subscriber Identity)의 노출로 인한 프라이버시 문제점을 해결하고, ECDH(Elliptic Curve Diffie Hellman) 기법으로 완전한 전방향 안전성을 제공하는 프로토콜을 제안한다.

  • PDF