• 소성∙가공
• /
• 제8권1호
• /
• pp.29-37
• /
• 1999

An analysis system for sheet metal forming(SAT_STAMP) has been developed to improve the design and tryout process by predicting the deformation behavior more precisely. This analysis system consists of forming analysis, springback analysis and post processor modules. The more accurate prediction of stress history can be achieved due to the improved contact algorithm. Continuous simulation of sequential processes can be carried out conveniently without interruption by the improved data management of the developed system. The error of data transfer between forming analysis and springback analysis is minimized using the proper shell element. Several benchmark test results and practical results are presented to show the effectiveness and reliability of this program.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 춘계학술대회 논문집
• /
• pp.1025-1030
• /
• 1997

In this study,the procedure of interpolation surface modeling on bicubic spline patch equation and NC machining are presented. The procedure consists of three parts : patch modeling,cutter location data generation,post processing and NC milling machining. For generation of the cutter location data,tangent vectors and units normal vectors on the patch must be calculated. In order to investigate the properties of the interpolation surface created by bicubic spline patch, two kinds of end conditions, clamped end condition and relaxed end condition,were applied in this study. The shape of the patch depends on the magnitide of the tangent vectors and twist vectors at the corners of bicubic surface patch. the patch generated by relaxed end condition more approximated to the surface patch which was given.

• Journal of information and communication convergence engineering
• /
• 제8권5호
• /
• pp.581-585
• /
• 2010

A grid was sandwiched between two cascaded imaging plates. Using a fan-beam X-ray tube and a single exposure scheme, the two imaging plates, respectively, recorded grid-less and grid type information of the object. Referring to the mathematical model of the Grid-less and grid technique, it was explained that the collected components whereas that of imaging plates with grid was of high together with large scattered components whereas that of imaging plate with grid was of low and suppressed scattered components. Based on this assumption and using a Gaussian convolution kernel representing the effect of scattering, the related data of the imaging plates were simulated by computer. These observed data were then employed in the developed post-processing estimation and restoration (kalman-filter) algorithms and accordingly, the quality of the resultant image was effectively improved.

• 한국전자통신학회논문지
• /
• 제5권1호
• /
• pp.51-57
• /
• 2010

본 논문은 일반적인 기상관측 부이시스템에서의 전자시스템설계에 관한 것이다. 주로 기지국, 데이터처리, 파워시스템설계 등의 기상관축 부이용 전자통신시스템 설계에 관한 것이다. 연구결과 시스템 설계가 기지국에서 부이를 통하여 배터리 사용시간을 확인하였고, 추가적인 파워의 소비 없이 자체적으로 부이에서의 작용함을 알 수 있다.

• 한국정밀공학회지
• /
• 제8권4호
• /
• pp.84-94
• /
• 1991

In order to achieve high accuracy of teaching and increase productivity using industrial robots in polishing process of dies, an off-line task programming system was developed on IBM-PC/386 under WINDOWS 3.0 operating system. The internal structure and the machematical basis of CAMPoli are described. Surface modeling technique of polishing dies with sculptured surfaces is introduced by poing data interpolation methodology through the use of CL-data transmitted from conventional CAM system. Tool selection, polishing speed, polishing pressure and kinds of tool motions can be determined and selected by user specified polishing variables. Task creation and verification of polishing path via computer graphics simulation of polishing tool can be done by the menu- driven function of CAMPoli system. Post-processing module is attached to generate robot language. Some simulation results are provided as verification means of the system.

• 한국ITS학회 논문지
• /
• 제8권1호
• /
• pp.76-81
• /
• 2009

ITS용 WSN과 같이 작고 건전지로 동작하는 송신 노드에서는 MCU의 성능이 낮고 메모리의 크기도 충분하지 않으며 소비전력을 줄이는 것이 매우 중요하다. 본 논문에서는 이런 환경에서 TCP/IP 통신을 할 때에 사용되는 TCP헤더 옵션 필드와 추가적인 체크섬 필드를 이용하여, 전송하는 데이터의 크기가 메모리의 크기에 제한을 받지 않고, 데이터 처리 시간과 소비전력을 감소시키는 방식이 제안되고 성능이 분석되었다.

• 대한원격탐사학회지
• /
• 제36권4호
• /
• pp.527-534
• /
• 2020

This study aims to monitor the displacement of the bridges using Stanford Method for Persistent Scatterers (StaMPS) time-series Persistent Scatterer Interferometric Synthetic Aperture Radar analysis. For case study bridges: Kimdaejung bridge and Deokyang bridge, we acquired 60 and 33 Cosmo-Skymed Synthetic Aperture Radar (SAR) data over the Mokpo region and Yeosu region, respectively from 2013 to 2019. With single-look interferograms, we estimated the long-term time-series displacements over the bridges. The time-series displacements were estimated as -8.8 mm/year and -1.34 mm/year at the mid-span over the selected bridges: Kimdaejung and Deokyang bridge, respectively. This time-series displacement provides reliable and high spatial resolution information to monitor the structural behavior of the bridge for preventing structural behaviors.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 춘계학술대회 논문집
• /
• pp.820-825
• /
• 2008

In the article 16 of the domestic rolling stock crashworthiness regulations, the collision acceleration level during collision accidents should remain under the maximum 7.5g and the average 5g. By the way, the accelerations obtained in crash simulations and tests contain many kinds of high frequency components due to numerical oscillations or noisy signals. So, this paper aims to develop reliable post-processing methods to filter high frequency oscillations and extract the rigid body motions of passenger rail cars. For this study we used the 1-dimensional dynamic model of KHST (Korean high-speed train), and evaluated acceleration data at the driver's area in the first power car and the passenger area in the following trailer.

• 디지털산업정보학회논문지
• /
• 제6권2호
• /
• pp.199-207
• /
• 2010

Recently, large amount of information in IDS(Intrusion Detection System) can be un manageable and also be mixed with false prediction error. In this paper, we propose a data mining methodology for IDS, which contains uncertainty based on training process and post-processing analysis additionally. Our system is trained to classify the existing attack for misuse detection, to detect the new attack pattern for anomaly detection, and to define border patter between attack and normal pattern. In experimental results show that our approach improve the performance against existing attacks and new attacks, from 0.62 to 0.84 about 35%.

• Journal of the Korean Data and Information Science Society
• /
• 제25권6호
• /
• pp.1557-1567
• /
• 2014

In this paper, I propose a general hypothesis that after the enactment of the Sarbanes-Oxley Act (SOA) financial statements convey more accurate and reliable corporate information to investors who in turn reflect such improvements in stock prices and test four practical hypotheses that simultaneously feature the degree of information asymmetry, forecast bias, and investor reaction to biased earnings information. The empirical results unanimously suggest that the post-SOA investors take advantage of the improvement in informational efficiency and accuracy and actively adjust for analyst forecast bias in earnings forecasts. The SOA indeed appears to achieve its primary goal of investor protection.