• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2040-2043
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• 2003

General-purpose MPEG-2 video transcoders must be able to achieve any conversion between 18 ATSC (Advanced television system committee) video formats for DTV (digital television), e.g., scan format, size format, and frame rate format conversion. Especially, scan format conversion is hard to implement because frame rate and size format conversion often happen together. This paper proposes a fast motion estimation(ME) algorithm for MPEG-2 video transcoding supporting scan format conversion. Firstly, we extract and compose a set of candidate motion vectors (MV's) from the input bit-stream to comply with the re-encoding format. Secondly, the best MV is chosen among several candidate MV's by using a weighted median selector. Simulation results show that the proposed ME algorithm reduces significantly transcoding complexity with a minor PSNR degradation.

• Investigative Magnetic Resonance Imaging
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• v.10 no.2
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• pp.108-116
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• 2006

Purpose : High-resolution spiral-scan imaging is performed at 3 Tesla MRI system. Since the gradient waveforms for the spiral-scan imaging have lower slopes than those for the Echo Planar Imaging (EPI), they can be implemented with the gradient systems having lower slew rates. The spiral-scan imaging also involves less eddy currents due to the smooth gradient waveforms. The spiral-scan imaging method does not suffer from high specific absorption rate (SAR), which is one of the main obstacles in high field imaging for rf echo-based fast imaging methods such as fast spin echo techniques. Thus, the spiral-scan imaging has a great potential for the high-speed imaging in high magnetic fields. In this paper, we presented various high-resolution images obtained by the spiral-scan methods at 3T MRI system for various applications. Materials and Methods : High-resolution spiral-scan imaging technique is implemented at 3T whole body MRI system. An efficient and fast higher-order shimming technique is developed to reduce the inhomogeneity, and the single-shot and interleaved spiral-scan imaging methods are developed. Spin-echo and gradient-echo based spiral-scan imaging methods are implemented, and image contrast and signal-tonoise ratio are controlled by the echo time, repetition time, and the rf flip angles. Results : Spiral-scan images having various resolutions are obtained at 3T MRI system. Since the absolute magnitude of the inhomogeneity is increasing in higher magnetic fields, higher order shimming to reduce the inhomogeneity becomes more important. A fast shimming technique in which axial, sagittal, and coronal sectional inhomogeneity maps are obtained in one scan is developed, and the shimming method based on the analysis of spherical harmonics of the inhomogeneity map is applied. For phantom and invivo head imaging, image matrix size of about $100{\times}100$ is obtained by a single-shot spiral-scan imaging, and a matrix size of $256{\times}256$ is obtained by the interleaved spiral-scan imaging with the number of interleaves of from 6 to 12. Conclusion : High field imaging becomes increasingly important due to the improved signal-to-noise ratio, larger spectral separation, and the higher BOLD-based contrast. The increasing SAR is, however, a limiting factor in high field imaging. Since the spiral-scan imaging has a very low SAR, and lower hardware requirements for the implementation of the technique compared to EPI, it is suitable for a rapid imaging in high fields. In this paper, the spiral-scan imaging with various resolutions from $100{\times}100$ to $256{\times}256$ by controlling the number of interleaves are developed for the high-speed imaging in high magnetic fields.

• Journal of the Korean Society of Radiology
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• v.10 no.5
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• pp.299-305
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• 2016

Despite of the development of medical equipments and technology. Pancreatic cancer has maked high false positive rate and low survival rate compared to other cancers. Therefore, early catch of pancreatic cancer is the only way to enhance the viability. It is important to find the exact location of the pancreas cancer in early stage. The method of optimum scan for early detection of pancreatic cancer on PET/CT exam is proposed. Examined the anatomical region that potentially can be missing from the supine position of ordinary pet/ct exam. The characteristics and usefulness of angle variation ($0^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, $90^{\circ}$) of patients scan position is analyzed. The proposed scan method (named JJ-projection) is bringing advantage of anatomical discrimination by separating stomach, liver, gallbladder duodenum and pancreas. ROC curve analysis is shows to advantage of the JJ-Projection method. The sensitivity has increased 4.6% than the supine delay scan method, the results sensitivity has increased from 91% to 95.2%. The specificity has increased from 75.1% to 84%. Compared with the results observed in cancer by biological biopsy, The accuracy has increased from 86.8% to 94.1%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.866-869
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• 2000

To improve quality of the ground surface, we have to consider a number of parameters. But it is difficult to make experiment with many parameters. Most of all experiments try to search optimal grinding condition with conservative factors such as feed rate, depth of cut, wheel rotating speed, etc. But This paper attempts to view the significance of some different factors effecting on the surface roughness by introducing helical scan grinding method and material removal rate. The design of experiment is used to find the optimal grinding condition which minimizes the surface roughness value bout optical glass material. To analyze experimental results, ANOVA(ANalysis of VAriation) is used. Discussion on the result about helical scan grinding is also given.

• Fashion & Textile Research Journal
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• v.22 no.5
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• pp.650-659
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• 2020

The present study provides reference data required for the design of clothing for the elderly by analyzing the body surface area during fitness motion based on 3D scan data of Korean elderly women. This study was conducted with the procedures of (1) survey of motions and main muscles for fitness, (2) acquisition of 3D scan data, and (3) analysis of rate of change for body surface area during fitness motion. Acquisition of 3D body scan data was obtained from seven elderly females (age: 64-77). We selected 66 anatomical landmarks (40 upper body and 22 lower body) by referring to previous studies. Body surface was segmented by connecting the landmarks marked on the 3D scan data acquired. Analysis of body surface area was conducted in terms of the change rate of surface area in 9 postures of elbow 0°, 90° and 180° for flexion, shoulder 90°, 180° for flexion, shoulder 0°, 180° for abduction, hip 90° for flexion, and knee 90° for flexion compared to the those in the standing posture. The amount of changes in body surface area were 12%-62% in the upper body, 15%-77% in the arm, and 10%-51% in the lower body. A future study on the rate of change of body surface length is needed; in addition, a study on how to apply the results of body surface area and body surface length analysis to clothing pattern design is also necessary.

• Childhood Kidney Diseases
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• v.21 no.2
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• pp.107-113
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• 2017

Purpose: This study aimed to evaluate the relationships between 99mTecnicium-dimercaptosuccinic acid (DMSA) scan findings and clinical parameters including age and fever duration. Methods: The positive rates for abnormal DMSA scans were analyzed according to the age of patients, fever duration prior to admission, and total fever duration. DMSA scan findings were divided into 3 categories: single defect, multifocal defects, and discrepant defects. We evaluated the detection rates of vesicoureteral reflux according to DMSA scan lesions. Results: Among a total 320 cases, 141 (44.1%) had abnormal DMSA scans. The infant group (0-1 year of age) had a shorter total fever duration, and a lower C-reactive protein (CRP) value and DMSA positive rate (39.8% vs. 60.6%, P=0.002) compared to children group (2-15 years of age). Patients with abnormal scans had a longer total fever duration and higher CRP compared to those with normal scans. The positivity rate of abnormal scans did not differ between the patients with a short fever duration prior to admission of ${\leq}2$ days and those with longer fever duration of ${\geq}3$ days. However, patients with longer total fever duration had a higher rate of abnormal DMSA scans (P=0.02). Among cases with a single defect, multifocal defects, and discrepant defects, vesicoureteral reflux was observed in 22.4%, 60% and 70.6% of cases, respectively (P=0.004). Conclusion: Although DMSA scan has limitations in early diagnosis, DMSA scan findings may aid in the prediction of the severity of systemic inflammation and detection of vesicoureteral reflux.

• Journal of KIISE:Information Networking
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• v.31 no.2
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• pp.171-178
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• 2004

Port scanning detection systems should rather satisfy a certain level of the requirement for system performance like a low rate of “False Positive” and “False Negative”, and requirement for convenience for users to be easy to manage the system security with detection systems. However, public domain Real Time Scan Detection Systems have high rate of false detection and have difficulty in detecting various scanning techniques. In addition, as current real time scan detection systems are based on command interface, the systems are poor at user interface and thus it is difficult to apply them to the system security management. Hence, we propose TkRTSD(Tcl/Tk Real Time Scan Detection System) that is able to detect various scan attacks based on port scanning techniques by applying a set of new filter rules, and minimize the rate of False Positive by applying proposed ABP-Rules derived from attacker's behavioral patterns. Also a GUI environment for TkRTSD is implemented by using Tcl/Tk for user's convenience of managing network security.

• The KIPS Transactions:PartA
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• v.16A no.2
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• pp.79-88
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• 2009

In boundary scan architecture, test stimuli are shifted in one at a time and applied to the on-chip system logic. The test results are captured into the BSR and are examined by subsequent shifting. In this paper, we developed a continuous capture test architecture and test procedure using TPG based on boundary scan is used to performance test. In this architecture, test patterns of TPG are applied to CUT with system clock rate, and response of CUT is continuously captured by CBSR(Continuous Capture Boundary Scan Register) at the same rate and the captured results is shifted to TDO at the same rate. The suggested a continuous capture test architecture and test procedure is simulated by Altera Max+Plus 10.0. The simulation results shows the accurate operation and effectiveness of the proposed test architecture and procedure.

• The Korean Journal of Nuclear Medicine Technology
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• v.19 no.2
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• pp.63-67
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• 2015

Purpose Among various causes that influence image quality degradation, various methods for decrease in Artifact occurred by respiration of patients are being used. Among them, this study intended to evaluate CTAC Shift correction method and additional scan compare to the Scan(Q static scan) using respiratory gated system. Materials and Methods This study was conducted on 10 patients, and used PET-CT Discovery 710 (GE Healthcare, MI, USA) and Varian's RPM system. 5.18 Mbq per kg of $^{18}F$-FDG was injected on patients, asked them to take a rest for 1 hour in the bed, and conducted test after urination. Images were visualized through Q static scan, CTAC Shift correction method, Additional scan based on the Whole body scan(WBS) with Artifact. Decrease in Artifact was compared in each image, conducted Gross Evalution, and measured changes of SUVmax. Results For image obtained through the CTAC Shift correction method through WBS with Artifact, 12~56%, Q static scan image showed 17~54% of change rate and Additional Scan showed -27~46% of change rate. In Blind Test, the CTAC Shift correction image showed the highest point with 4 points, Q static scan image showed 3.5 points, and Additional scan image showed 3.4 points. The standardized WBS scan through Oneway ANOVA and three types of Scan method showed significant difference(p<0.05), and did not show significant difference between the three Scan methods(p>0.05). However, the three Scan methods showed significant difference in Blind test. Conclusion Additional scan and Q static scan require more time than the CTAC Shift correction method, there is concern about excessive exposure to patients by CT rescan and Q static scan is difficult to apply on patients with inconsistent respiration or irregular respiration cycle due to pain. For CTAC Shift correction method, limited correction is possible and the range is limited as well. It is considered as a useful method of improving diagnostic value when hospitals use the system appropriately and develop various advantageous factors of each method.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.9
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• pp.165-170
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• 2001

In normal grinding abrasive particles of a grinding wheel rotate on planes parallel to the direction of workpiece fred. which may induce continued scratch lines on ground surface as the workpiece feeds. Instead in helical scan grinding the planes make an angle, called a helical angle, with the feeding direction. Thus scratch lines produced by abrasive particles per one revolution are discontinued which implies that the generation of scratch lines are suppressed by the helical scan grinding. In this study some experimental works have been done on the helical scan grinding of glass to find the effects of grinding conditions on the surface roughness and estimate the optimal grinding conditions. The helical angle, fred rate, material removal rate and the wheel speed are taken as factors for three kinds of grinding wheels i.e., coarse(#140 mesh), medium(#400) and fine(#800) diamond wheels. The experiments are scheduled by Taguchi technique and ANOVA has been carried out for the interpretation of the results. As a result of this study effects of the factors are verified quantitatively showing that the major factors are changed according to the wheel's mesh size and the helical angle is one of the influencing factors on the surface quality.