• Journal of the Korean Society for Precision Engineering
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• v.31 no.4
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• pp.297-301
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• 2014

The biggest factors, which lower the machining accuracy of machine, are thermal deformation and chatter vibration. In this article, we introduce the development case of a device and technology that can automatically compensate thermal deformation errors of machine during long-time processing on the machine tool's CNC (Computerized Numerical Controller) in real time. In machine processing, the data acquisition of temperature signal in real time and auto-compensation of the machine origin of machine tools depending on thermal deformation have significant influence on improving the machining accuracy and the rate of operation. Thus, we attempts to introduce the related contents of the development we have made in this article : The development of a device that embedded the acquisition part of temperature data, linear regression to get compensation value, compensation model of neural network and a system that compensates the machine origin of machine tool automatically during manufacturing process on the CNC.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.294-298
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• 1997

In the magnetic resonance imaging, the fast spin echo imaging technique is a widely used clinical imaging method, since its scanning time is much shorter than the conventional spin echo imaging and it gives the almost same image quality. However, the fast spin echo technique has two times longer imaging time or the dual echo acquisition which can obtain a spin density image and a $T_2$-weighted image simultaneously. To overcome such a drawback, this paper proposes a new fast dual echo imaging technique which can give the same quality images at the single echo imaging time. The proposed technique reduces the imaging time by overlapping most of echo train data for each image reconstruction. In order to verify its validity and usability the human head experimental results which were obtained at the 0.3T permanent MRI system are presented.

• Journal of Electrical Engineering and Technology
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• v.5 no.1
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• pp.16-20
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• 2010

Recently, the smart grid has become a hot issue and interest in related power sources have increased accordingly. The implementation of a smart grid can enable many generation resources to be linked to the power system, including small-scale reactors for the purpose of co-generation. Research on small-scale reactors is being carried out all over the world. Similarly, Korea is also conducting research on multi-purpose regional energy systems using nuclear energy. This paper proposes a real-time data acquisition and analysis system for small-scale reactors, and is known as the REX-10 (Regional Energy rX 10 MVA). This analysis requires real-time simulations for the power system since it needs data communication with a remote REX-10. A RTDS (Real Time Digital Simulator) has been used for the simulation, and a SCADA/HMI system interfaced with the RTDS is proposed for the purpose of monitoring and control of the regional energy system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1188-1191
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• 2003

In this paper, we focus our attention on the improvement of locking time and jitter parameter and propose the new structure of PLL which combined with the FVC, FOVI Matcher(FVC-Output and VCO-input Matching Circuit), Control Circuit and the conventional charge pump PLL. Using fast operation characteristics of the FVC, the circuit matching FVC-Output and VCO-input (FOVI Matcher) made to synchronize very fast. Fast locking time is usually required for application where the PLL has to settle rapidly if they switch from an idle mode to a normal mode and to track high-frequency data bit rate in data recovery systems. After a fast acqusition is achieved by the using the FVC, the conventional PLL operates for removing the phase error between the reference signal and the feedback signal. Therefore this structure can improve the trade-off between acquisition behavior and locked behavior.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.67-72
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• 2002

Real-time techniques are motivated by a number of factors including the potential for direct acquisition of diagnostic quality images, facilitation of patient-specific imaging parameters, and reduced examination time. Real-time MRI includes not only a rapid pulse sequence but also high speed image reconstruction and easy interactivity. The frame rate of the real-time technique used should be matched to the physiological timeframes under study. Principal applications thusfar have been in localization, fluoroscopic triggering, guidance of other processes, and potentially in the generation of diagnostic images of moving structures.

• The Bulletin of The Korean Astronomical Society
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• v.29 no.2
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• pp.58.2-58.2
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• 2004

• 한국항공운항학회:학술대회논문집
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• 2004.11a
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• pp.266-269
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• 2004

• 재활복지
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• v.22 no.1
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• pp.27-49
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• 2018

The purpose of this study was to analyze the relationship between social interaction, role acquisition, and self-identity of people with physical disabilities participating in daily sports. In order to accomplish the purpose of this study, people with physical disabilities residing in Busan, Gyeongnam, and Gyeongbuk were set as a population. Among them, 384 people with physical disabilities participating in daily sports were sampled using convenience sampling. Data were analyzed by frequency analysis, exploratory factor analysis, reliability analysis, multiple regression analysis, and simple regression analysis using the SPSS 23.0 program. The results were as follows. As a result of analyzing the effects of participation level of daily sports for people with physical disabilities on social interaction, role acquisition, and self-identity, first, participation period had a significant effect on ego-identity. Second, participation time did not have a statistically significant effect on social interaction, role acquisition, and self-identity. Third, participation frequency had a significant effect on social interaction, role acquisition, and self-identity. In addition, social interaction, role acquisition, and self-identity showed a statistically significant correlation with positive effects as a result of analyzing the relationship between social interaction, role acquisition, and self-identity.

• Journal of Korea Multimedia Society
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• v.10 no.6
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• pp.726-736
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• 2007

In this paper, real-time image scanning system using linescan cameras is designed. The system is specially designed to diagnose and analyse the conditions of tunnels such as crack widths through the captured images. The system consists of two major parts, the image acquisition system and the image merging system. To save scanned image data into storage media in real-time, the image acquisition system has been designed with two different control and management modules. The control modules are in charge of controlling the hardware device and the management modules handle system resources so that the scanned images are safely saved to the magnetic storage devices. The system can be mounted to various kinds of vehicles. After taking images, the image merging system generates extended images by combining saved images. Several tests are conducted in laboratory as well as in the field. In the laboratory simulation, both systems are tested several times and upgraded. In the field-testing, the image acquisition system is mounted to a specially designed vehicle and images of the interior surface of the tunnel are captured. The system is successfully tested in a real tunnel with a vehicle at the speed of 20 km/h. The captured images of the tunnel condition including cracks are vivid enough for an expert to diagnose the state of the tunnel using images instead of seeing through his/her eyes.

• Restorative Dentistry and Endodontics
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• v.38 no.3
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• pp.146-153
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• 2013

Objectives: Aluminum step wedge (ASW) equivalent radiodensity (eRD) has been used to quantify restorative material's radiodensity. The aim of this study was to evaluate the effects of image acquisition control (IAC) of a digital X-ray system on the radiodensity quantification under different exposure time settings. Materials and Methods: Three 1-mm thick restorative material samples with various opacities were prepared. Samples were radiographed alongside an ASW using one of three digital radiographic modes (linear mapping (L), nonlinear mapping (N), and nonlinear mapping and automatic exposure control activated (E)) under 3 exposure time settings (underexposure, normal-exposure, and overexposure). The ASW eRD of restorative materials, attenuation coefficients and contrasts of ASW, and the correlation coefficient of linear relationship between logarithms of gray-scale value and thicknesses of ASW were compared under 9 conditions. Results: The ASW eRD measurements of restorative materials by three digital radiographic modes were statistically different (p = 0.049) but clinically similar. The relationship between logarithms of background corrected grey scale value and thickness of ASW was highly linear but attenuation coefficients and contrasts varied significantly among 3 radiographic modes. Varying exposure times did not affect ASW eRD significantly. Conclusions: Even though different digital radiographic modes induced large variation on attenuation of coefficient and contrast of ASW, E mode improved diagnostic quality of the image significantly under the underexposure condition by improving contrasts, while maintaining ASW eRDs of restorative materials similar. Under the condition of this study, underexposure time may be acceptable clinically with digital X-ray system using automatic gain control that reduces radiation exposure for patient.