• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.2
• /
• pp.227-233
• /
• 2001

Electromagnetic field characteristics of Reverberation chamber, which could be applicable for an alternative test facility of electromagnetic interference and radiated electromagnetic susceptibility have been investigated. To obtain the required field uniformity of reverberation chamber, Schroeder method Quadratic Residue Diffuser was designed to be applied to chamber. In this paper, 3 different types of diffusers depending on diffuser's periodic direction have been used to investigate field characteristics of each type by using FDTD numerical method. The results show all 3 types of reverberation chambers have below $\pm$3 dB tolerance of field uniformity characteristics, and the symmetrical, type 3, structure show better results among them.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.11 no.5
• /
• pp.839-848
• /
• 2000

This paper presents the results of an electromagnetic field analysis for a reverberation chamber that is an alternative method of a shielded anechoic chamber, which is widely used for the analysis and measurement of electromagnetic interference and immunity test. Inside the defined test volume of the rectangular and triangular type, the Schroeder Quadratic Residue Diffuser was employed. FDTD(Finite-Difference Time-Domain) simulation method was applied to produce the field characteristics inside those reverberation chambers. According to the results, field uniformities on the aforementioned two types of reverberation chambers were correlated within $\pm$3dB, and $\pm$4.4dB tolerances, and rectangular type reverberation chamber shows an independent polarization result.

• Journal of the Korean Geophysical Society
• /
• v.2 no.4
• /
• pp.241-250
• /
• 1999

Reflection coefficients of the seafloor have been calculated from the amplitude ratio of secondary to primary water bottom reflection in seismic data obtained from Bransfield Strait, Antarctic Peninsula. Test processing for the coefficients shows that moving average is effective to reduce severe fluctuation of the coefficient measured at each point. Relationship between the coefficients and the properties of water bottom is analyzed to illuminate geological environment. In the central Bransfield Basin, the magnitude of reflection coefficients decreases as it is distant from the sedimentary sources. Reflection coefficients range from 0.12 to 0.2 near the continental slope of the basin, and from 0.1 to 0.12 in the basin floor. In the western Bransfield basin, reflection coefficients between 0.2 to 0.3 are obtained from the area eroded by glacial movement. On the volcanic structures near Deception Island, the coefficients show relatively high values more than 0.2. Paleo-geological structures uplifted by tectonic movement and outcropped by glacial erosion have relatively high coefficients.

• Industry Promotion Research
• /
• v.2 no.1
• /
• pp.1-7
• /
• 2017

In the case of manufacturing companies, various types of data are collected. Many of these data can be used as useful information for product reliability evaluation. In this study, we first look at data that can be collected by a manufacturing company and related to products, technology, finance, and customers. Next, we will look at the company's business management system, scientific journals, test and marketing survey data, etc., as sources of data. Next, look at what kind of data is collected over the product life cycle to evaluate the reliability of the product. In the development stage of the product, reliability test is performed for each component, and reliability data is collected by performing reliability test at the subsystem and system level. On the other hand, at the manufacturing stage, data on the functional test and the design change test of the product are collected, and at the field stage, the problem of the product is detected in the field and collected in the form of data. Finally, let's look at what you need to do to make a reasonable analysis later in your data collection.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2006.05a
• /
• pp.281-284
• /
• 2006

최근 산업용 내장형 소프트웨어는 높은 부가가치를 창출할 수 있는 분야로 각광을 받고 있다. 최근 산업용 기기의 하드웨어뿐 아니라 내장형 소프트웨어에 대한 품질 시험 및 인증을 위한 기반 연구가 활발히 수행되고 있다. 본 연구는 산업용 소프트웨어 국제표준 적합성 인증」사업 추진과 관련하여 산업용 소프트웨어의 통신 기능에 대한 성능 평가 시험을 위하여 다양한 통신 프로토콜을 지원하는 시뮬레이션 소프트웨어를 개발한 것이다 소프트웨어는 산업용 통신 프로토콜인 필드버스 방식(Profibus, DeviceNet, CAN, RS232C, RS485, RS422등) 및 이더넷 기반의 TCP/IP 프로토콜에 대한 통신 시뮬레이션 시험 기능을 가지고 있으며, 프로토콜별 패킷 프레임을 사용자가 임의적으로 설정할 수 있게 하여 다양한 통신환경에서의 시뮬레이션 시험을 지원하고 각 프로토콜은 단방향 및 양방향시험을 모두 지원한다. 본 논문에서는 프로토콜별 시험 항목 및 방법을 소개하고 시뮬레이선 시스템의 하드웨어와 소프트웨어 구성 및 운영환경을 기술하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2009.11a
• /
• pp.325-328
• /
• 2009

지상파 DMB가 널리 보급되고, 이를 활용한 재난경보서비스가 시험방송을 준비 중이다. 그러나 검증되지 않은 수신기들이 대량으로 출시되어 BIFS 대란과 같은 문제점도 발생하였다. 재난경보방송은 정확한 정보 전달이 매우 중요하므로, 이와 같은 문제가 발생하지 않도록 하기 위한 '지상파 디지털멀티미디어방송(DMB) 재난경보방송 수신기 표준적합성 시험'을 두고 있다. 이 표준을 분석한 결과 추가되어야 할 시험 방목이 몇 가지 발견되었다. 이 논문에서는 '지상파 디지털멀티미디어방송(DMB) 재난경보방송'의 메시지 포맷을 분석하여 각 필드가 모순되는 경우와, 사용하지 않는 값이라 명시하였으나 시험 항목에 누락된 부분을 파악하여 보충하였다. 이러한 시험 항목을 이용하면 표준을 보완하고, 결함이 더 적은 수신기를 개발하는데 도움이 될 것이다.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.1
• /
• pp.1-8
• /
• 2013

Recently, the automotive technology has developed with electronics and information technology as convergence technology while vehicles had been regarded as machines. Moreover, vehicles are becoming more intelligent and safer devices, assembly of advanced technologies by customers' demand. Even though all of installations of vehicle have attracted as diverting devices, it cause drivers' mistakes like delay of response on traffic condition. Here, we proposed the Field Operational Test (FOT) environment which could be used as driving and road conditions collector(Vehicle motion, Traffic condition, Driver input, Driver state, etc.) for researches about Driver Friendly Intelligent System(SCC, LDWS, etc.), Human Vehicle Interface(Driving Workload, etc.) and Economic Drive Model. Furthermore driving patten and fuel consumption patten of drivers were analyzed by measured data and direction of future research was suggested.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.49 no.12
• /
• pp.981-988
• /
• 2021

This paper presents a decentralized guidance algorithm for swarm flight of fixed-wing UAVs (Unmanned Aerial Vehicles). Considering swarm flight missions, we assume four representative swarm tasks: gathering, loitering, waypoint/path following, and individual task. Those tasks require several distinct maneuvers such as path following, flocking, and collision avoidance. In order to deal with the required maneuvers, this paper proposes an integrated guidance algorithm based on vector field, augmented Cucker-Smale model, and potential field methods. Integrated guidance command is synthesized with heuristic weights designed for each guidance method. The proposed algorithm is verified through flight tests using up to 19 small fixed-wing UAVs.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2017.06a
• /
• pp.139-142
• /
• 2017

지상파 방송 3사(KBS, MBC, SBS)는 2017년 5월 31일부터 지상파 UHD(Ultra High Definition Television) 본방송을 개시하였다. ATSC(Advanced Television Systems Committee) 3.0 표준방식으로 이루어진 세계 최초 지상파 UHD 본방송으로써, 국내뿐만 아니라 미국, 일본, 유럽의 DTV선진국에서도 많은 관심을 보이고 있다. 본 논문에서는 시험방송 기간에 방송사와 가전사가 공동으로 실시한 ATSC 3.0 기반 지상파 UHD 본방송을 위한 물리계층 필드테스트 결과에 대해 살펴보고자 한다.

• Journal of Advanced Navigation Technology
• /
• v.21 no.4
• /
• pp.325-331
• /
• 2017

As a GPS stability problem arises, MLAT system is spotlighted as an alternative technology of ADS-B. MLAT system has a high position accuracy as much as ADS-B. Also, MLAT receives the mode A,C,S, and 1090ES(ADS-B) signals from the mounted aircraft transponder. MLAT receives signals from several receiver units and calculates aircraft positions. MLAT has ADS-B level positioning accurarcy using GPS and can calculate the position information with objects independently. According to global environment changes, Local area multiltilateration(LAM) surveillance system is under development for moving vehicles and aircraft detection in airport. These are still under testing in Tae-an Airfield. In the paper, we analyzed the performance by comparing the calculated position data from MLAT to RTK. In order to confirm the position accuracy of MLAT and the deviation of position data between fixed target and moving target on the ground during the field test in Tae-an Airfield.