• Journal of radiological science and technology
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• v.20 no.2
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• pp.34-43
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• 1997

There are 4 types of equipment in diagnostic radiography. These are single phase, three phase, inverter type and condenser type X-ray generators. It is very confusing to make an adequate exposure factor and to know the usage of different type of X-ray generators. In this experiment, I explored a comparative study of outputs in 4 different type of X-ray units. I expect that this experiment could be helpful for manufacturer to make both the X-ray equipment better, In terms of Ideal exposure factors, thereby reducing the patient dose. Experimental results are as follow : 1) X-ray output The ratio of X-ray output of single, three phase and inverter type of X-ray generator was 1 : 1.6 : 2 without absorber and 1 : 2 : 2.6 with 20 mm aluminium absorber. 2) Beam quality The X-ray beam quality of single phase generator was proved to be softer than three phase and inverter type of generators by 0.4 mmAL and 0.55 mmAl HVL respectively. 3) Reproducibility Linearity of X-ray output Retroducibility of X-ray output met the regulation below CV 0.05 and linearity also met the regulation below 0.1 in 4 types of diagnostic X-ray generators. 4) The comparison of incident dose Three phase X-ray generator was 20% higher than two other X-ray generators in radiation dose to make same film density.

• Journal of radiological science and technology
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• v.42 no.4
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• pp.285-290
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• 2019

Magnetic resonance imaging is a technique specialized in soft tissue imaging with high contrast resolution without in vivo ionization and has been widely used in various clinical settings. In particular, the recent increase in social stress factors has been used in the diagnosis of pituitary adenoma, the incidence increases rapidly. Recently, due to the development of magnetic resonance imaging, it is possible to diagnose micro pituitary adenoma, but despite the use of contrast medium, there has been a difficulty in diagnosing the pituitary adenoma due to its small size and noise. In order to solve this problem, a proposed method of separating signal components image and noise components image from a measured image is applied, and the improvement of diagnostic efficiency is attempted by removing noise. As a result, it was confirmed that the image quality was improved as a whole by applying SNR for 30 subjects data. It is expected that this study will be useful as a pre-processing method for improving the image quality and developing diagnostic indicators of pituitary adenoma.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7C
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• pp.671-680
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• 2009

The diagnostic medical images(CT, MRI) in PACS require large storage and long transmission time. A simple and cheap way of overcoming these limitations is to increase the compression ratio. However, this requires a clinical validation for accurate diagnostic applications. The aim of this paper is to improve the compression efficiency of lossless JPEG2000 for diagnostic CT images by performing a visual-Iossless threshold filtering in high frequency subband. A proposed method, based on 5/3 reversible DWT, provides different subband-threshold values according to the compression ratio and gives the high subjective quality to reconstructed diagnostic CT images.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.11
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• pp.1067-1071
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• 2006

Prior to destructive testing, diagnostic tests were performed in ten high voltage motors. Diagnostic tests included polarization infer, ac current, dissipation factor$(tan{\delta})$ and partial discharge magnitude. The rewind of motet slater insulation at rated voltage is assessed by the results of these tests. After completing the diagnostic tests, the stator windings of motors were subjected to gradually increasing ac voltage, until the insulation punctured. No. 8 motor failed near rated voltage of 19.0 kV. The breakdown voltage of No. 4 motet was 7.0 kV which is lower that expected for good quality coils in 6.6 kV class motors. The failure was located in a line-end coil at the exit from the core slot. These two motors began operation in 1994. While testing No. 7 motor, flashover occurred between the stator winding and the stator frame at 15 kV. The relationship between the diagnostic test and the drop in insulation breakdown voltage was analyzed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.200-203
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• 2006

Prior to destructive testing, diagnostic tests were performed in eight high voltage motors. Diagnostic tests included polarization index, ac current, dissipation factor($tan{\delta}$) and partial discharge magnitude. The rewind of motor stator insulation at rated voltage is assessed by the results of these tests. After completing the diagnostic tests, the stator windings of motors were subjected to gradually increasing ac voltage, until the insulation punctured. No. 1 motor failed near rated voltage of 12.96 kV. The breakdown voltage of No. 4 motor was 6.99 kV which is lower that expected for good quality coils in 6.6 kV class motors. The failure was located in a line-end coil at the exit from the core slot. These two motors began operation in 1994. While testing No. 7 motor, flashover occurred between the stator winding and the stator frame at 15 kV. The relationship between the diagnostic test and the drop in insulation breakdown voltage was analyzed.

• Journal of Biomedical Engineering Research
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• v.40 no.3
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• pp.97-104
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• 2019

To examine different types of influenza diagnostic test kits automatically, automated rapid influenza diagnostic test method based on image recognition is proposed in this paper. First, the proposed methods classify a variety of the rapid influenza diagnostic test kit based on support vector machine that analyzes the kits' feature point. Then, to improve the accuracy of test, the proposed methods match the histogram of both the target image of influenza kit and the input image of influenza kit for minimizing the effect of environment factors, such as lighting and exposure variations. And, to minimize the effect from composition of the hand-helds devices, the proposed methods extract the feature point and match point-by-point between target image of influenza kit and input image of influenza kit. Experimental results of 124 experimental group show that the proposed methods significantly have effectiveness, which shows 90% accuracy in moderate antigen, for the preliminary examination of influenza, and provides the opportunity for taking action against influenza.

• Journal of the Korea Safety Management & Science
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• v.16 no.4
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• pp.433-439
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• 2014

Beam quality is changed about magnetic field of bending magnet. Evaluation of beam quality using PDD(Percentage Depth Dose) at 10cm depth at recommendation of AAPM(America Academy of Pain Medicine). However this evaluation shows fragmentary element. Therefore this study is applied to three value, 10cm divided by 5cm depth PDD, 20cm divided by 10cm depth PDD, 30cm divided by 20cm depth PDD, at change the magnetic field. PDD is measured at magnetic field changed ${\pm}1%$, ${\pm}2%$ at 6MV(Mega Voltage), 10MV photon. The plan technique is 3 portal plan using Core-Plan at human pelvic phantom. Conventional and presented methods are compared at maximum and minimum dose. The presented method increased discernment of relieve the unequal distribution and energy area than conventional method. Henceforth, application of presented method will be considered. Development of energy measurement method and detector miniaturization will be needed about continuous study.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.476-483
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• 2000

Like other vehicles, the suspension elements of railway rolling stock have influence on running stability and ride quality. Thus, faults detection for suspension elements is important to prevent an accidents of train and to ensure safety against derailment. This study was started to grasp the feasibility of diagnostic method for the suspension elements of bogie without disassembling. Through several tests by running test rig, we found that fault detection for suspension elements was possible. Here, we describe some results.

• Proceedings of the Korean Society of Medical Physics Conference
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• 1999.11a
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• pp.238-239
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• 1999

• Journal of radiological science and technology
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• v.14 no.2
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• pp.33-36
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• 1991