• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.3
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• pp.57-62
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• 2022

Recently, the tracking radar continues research to develop a new operation algorithm that can acquire and track a target in various environments. In general, modeling similar to the real target and environment is used to develop a new operation algorithm, but there is a limit to modeling the real environment. In this paper, a RAW data storage device was developed to efficiently develop a new operation algorithm required for the tracking radar using millimeter wave to acquire and track the target. The RAW data storage equipment is designed so that the signal processing device of the tracking radar using millimeter wave can save the RAW data output from 8 channels to OOOMSPS. RAW data storage equipment consists of data acquisition equipment and data storage equipment. The data acquisition equipment was implemented using a commercial Xilinx KCU 105 Evaluation KIT capable of high-speed data communication interface, and the data storage equipment was implemented by applying a computer compatible with the commercial Xilinx KCU 105 Evaluation KIT. In this paper, the performance of the implemented RAW data storage equipment was verified through repeated interlocking tests with the signal processing device of the millimeter wave tracking radar.

• Journal of Food Hygiene and Safety
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• v.27 no.3
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• pp.233-246
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• 2012

In this study, we investigated the applicability of the photostimulated luminescence(PSL), thermoluminescence(TL) and electron spin resonance(ESR) methods for various foods which are not allowed to be irradiated in Korea. All 15 foods including sesame, almond, peanut, cocoa powder etc. were analyzed. Samples were irradiated at 1~10 kGy using a $^{60}Co$ gamma-ray irradiator. In PSL study, the photon counts of all the unirradiated samples showed negative(lower than 700). The photon counts irradiated(1 kGy) dried shrimp, roasted peanut and seasoned peanut showed positive(higher than 5,000) and the other samples were negative or intermediate(> 700 and < 5,000). In TL analysis, results showed that it is possible to apply TL method to all foods containing minerals. In ESR measurements, the ESR signal(single-line) intensity of irradiated foods was higher than non-irradiated foods. In particular, the specific ESR signals of irradiation-induced crystalline sugar, cellulose and bone radical were detected in dried plum, raisin, dried cherry, mango(dried, frozen), rambutan, cocoa(powder), cinnamon, parsley, carrot, broccoli, dried arrow squid, dried pollack and dried shrimp. According to the results, PSL, TL and ESR methods were successfully applied to detect the irradiated foods because TL method is not able to detect the irradiated foods rarely composed of minerals. ESR is also a difficult method to detect the changes of ESR signal patterns of food. It is concluded that TL analysis or ESR assay is suitable for detection of irradiated samples and a combined method is recommendable for enhancing the reliability of detection results.

• The Journal of Korean Society for Radiation Therapy
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• v.23 no.2
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• pp.97-102
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• 2011

Purpose: IMRT QA using 2Dimensional array detector is carried out with condition for discrete dose distribution clinically. And it can affect uncertainty of evaluation using gamma method. We analyze gamma index variation according to grid size and suggest validate range of grid size for IMRT QA in Hospital. Materials and Methods: We performed QA using OniPro I'mRT system software version 1.7b on 10 patients (head and neck) for IMRT. The reference dose plane (grid size, 0.1 cm; location, [0, 0, 0]) from RTP was compared with the dose plane that has different grid size (0.1 cm, 0.5 cm, 1.0 cm, 2.0 cm, 4.0 cm) and different location (along Y-axis 0 cm, 0.2 cm, 0.5 cm, 1.0 cm). The gamma index variation was evaluated by observing the level of changes in Gamma pass rate, Average signal, Standard deviation for each case. Results: The average signal for each grid size showed difference levels of 0%, -0.19%, -0.04%, -0.46%, -8.32% and the standard deviation for each grid size showed difference levels of 0%, -0.30%, 1.24%, -0.70%, -7.99%. The gamma pass rate for each grid size showed difference levels of 0%, 0.27%, -1.43%, 5.32%, 5.60%. The gamma evaluation results according to distance in grid size range of 0.1 cm to 1.0 cm showed good agreement with reference condition (grid size 0.1 cm) within 1.5% and over 5% in case of the grid size was greater than 2.0 cm. Conclusion: We recognize that the grid size of gamma evaluation can make errors of IMRT QA. So we have to consider uncertainty of gamma evaluation according to the grid size and apply smaller than 2 cm grid size to reduce error and increase accuracy clinically.

• The Journal of the Acoustical Society of Korea
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• v.21 no.2E
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• pp.56-62
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• 2002

This paper describes a new method of stability evaluation for an estimated impulse response of a plant. It is difficult for the conventional stability evaluation equation to be used in an adaptive feedforward control system which uses an immeasurable acoustic transfer system of a real plant, because the equation requires an exact true impulse response of the plant. Therefore, the usefulness of the conventional equation is limited in a computer simulation. The proposed method is applicable to not only a computer simulation but also a real feedforward adaptive control system. It is found that the system is stable when the value of misadjustment is below -10 dB through computer simulations and experiments. And also, it is proved that the error signal is stable through the verification using filtered reference and filtered error LMS methods.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.615-616
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• 2008

Generally, distance between sensor nodes is measured using received signal strength indicator (RSSI) in wireless sensor network (WSN). Since RSSI is not absolutely accurate and stable in indoor environment, the performance of position estimation largely depends on estimation methods. In this paper, performance evaluation is presented to compare trilateration based positioning technique and collaborative ranging (CR) technique. From evaluation results, CR method is shown to be better than trilateration based method in terms of accuracy and precision.

• Journal of the Korean Society for Railway
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• v.9 no.5 s.36
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• pp.612-617
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• 2006

As the on-board electric devices determine the performances of vehicles, production of reliable devices is important. To keep the reliability of devices constant, management of performance evaluation of the on-board devices is crucial. Because temperature has a serious effect on failures of the components of the devices, its measurement is the first step for good management. In this study, we described performance characteristics of domestic auxiliary block developed through G7 project. We measured the performances of auxiliary block during test running by the developed on-line measurement system. After we save the input real-time data from each signal of Korean High Speed Train through the network line, we can acquire necessary information through post-processing program. We verify the motor block characteristics of Korean High Speed Train by this system.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.25-29
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• 2010

Safety of railroad is result of reliability which is received from test & evaluation of system. Railroad system is consisted of various sub system such as vehicle, supply of electric power, signal, communication, rail track construction, operation. To secure safety of railroad, evaluation about parts, assembly, sub system, whole system etc.. that compose railroad is essential. In this paper, I wish to describe for results that analyze korean tilting vehicle's derailment coefficient developed by national research achievement. Confirmed that is possible even if speed up, curved line department running speed that estimate korean tilting vehicle's running safety in curved line track of Jungang Line about 20 km/h than present operating speed.

• Progress in Superconductivity
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• v.3 no.2
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• pp.159-162
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• 2002

We have detected cracks inside multi-layer metal sheets with nondestructive evaluation system consisting of SQUID gradiometer. Double D-shape coil was carefully designed with computer simulation for spatial distribution of magnetic field. It was aligned and placed in between SQUID and metal sheets in order to reduce the field effect to SQUID and to maximize eddy current in the sheets. The metal plate in bottom of the metal stack contained artificial cracks which were scanned by an X-Y scanning system. The information of crack position and size could be estimated by analysis of SQUID signal. Details of the results will be discussed .

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1587-1591
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• 2009

Safety of railroad is result of reliability which is received from test & evaluation of system. Railroad system is consisted of various sub system such as vehicle, supply of electric power, signal, communication, rail track construction, operation. To secure safety of railroad, evaluation about parts, assembly, sub system, whole system etc.. that compose railroad is essential. In this paper, I wish to describe for results that analyze korean tilting vehicle's derailment coefficient developed by national research achievement. Result that evaluation korean tilting vehicle's running safety, verified that secure even if speed-up 30 km/h than operating speed of present in curved track.

• Journal of the Korea Safety Management & Science
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• v.11 no.3
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• pp.209-216
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• 2009

A development in method of evaluating the measurement precisions using approximate F tests and variance components from expected mean square (EMS) is investigated. The research proposes three-factor mixed measurement models with the fixed and random factors. Unrestricted and unconstrained design work was rarely studied, while restricted and constrained designs have been significantly discussed. The unrestricted and unconstrained designs assume to be an independence of interaction. The proposed evaluation method about the measurement precisions can be extended to four-factor random measurement model or mixed measurement model. The study also presents the three evaluation indexes of precisions such as R&RTR (Reproducibility & Repeatability-To-Total Precision Ratio), PTR (Precision-To-Tolerance Ratio), and SNR (Signal-To-Noise Ratio). Numerical examples are proposed to evaluate the approximate F tests with Satterthwaite degrees of freedom and three indexes using the measurement precisions from EMS.