• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.124-131
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• 2013

The most important thing in Plasma simulation is the etching process in which etch rate is calculated based on feature profile. Although there are various components to consider in calculating etch rate such as Ion Flux, Neutral, gas, and temperature, Addressing of this paper is limited to Ion Flux. This paper propose a scan method to compute Ion Flux faster for Plasma simulation. Also, this paper experiments and compares generally used Monte Carlo method and the proposed method based on gaussian and cosine distribution. Lastly, this paper proves that the proposed method can calculate accurate Ion Flux more efficiently than Monte Carlo method.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.55-60
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• 2004

In this study, the configuration and tension of a towing cable for side-scan sonar are predicted in an ambient flow and at an unsteady towing condition. The governing equation of three-dimensional dynamic analysis for a flexible cable is solved using a finite difference method. We successfully predict the configuration and tension of a side-scan sonar and designed the towing system. It is found in static analyses that the side-scan sonar must be towed to keep a its stable depth at a reasonable speed. The study also reveals in the transient analyses that the dominant component affecting the top tension is the tangential drag force for the larger towing speed than the critical speed, and the self weight of a towed instrument for the smaller towing speed than. It should be maneuvered for a towing vessel with good consideration for the impact effect in a cable due to tension peak when a towing speed is suddenly increase. The developed program can be applicable for three-dimensional dynamic analysis of a towing system for various marine survey instruments.

• Journal of the Korean Society for Nondestructive Testing
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• v.9 no.1
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• pp.30-38
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• 1989

Since the nuclear power plants in Korea have been operated in 1979, the nondestructive testing (NDT) of pressure vessels and/or piping welds plays an important role for maintaining the safety and integrity of the plants. Ultrasonic method is superior to the other NDT method in the viewpoint of the detectability of small flaw and accuracy to determine the locations, sizes, orientations, and shapes. As the service time of the nuclear power plants is increased, the radiation level from the components is getting higher. In order to get more quantitative and reliable results and secure the inspector from the exposure to high radiation level, automation of the ultrasonic equipments has been one of the important research and development(R & D) subject. In this research, it was attempted to visualize the shape of flaws presented inside the specimen using a Modified C-Scan technique. In order to develope Modified C-Scan technique, an automatic ultrasonic scanner and a module to control the scanner were designed and fabricated. IBM-PC/XT was interfaced to the module to control the scanner. Analog signals from the SONIC MARK II were digitized by Analog-Digital Converter(ADC 0800) for Modified C-Scan display. A computer program has been developed and has capability of automatic data acquisition and processing from the digital data, which consist of maximum amplitudes in each gate range and locations. The data from Modified C-Scan results was compared with shape from artificial defects using the developed system. Focal length of focused transducer was measured. The automatic ultrasonic equipment developed through this study is essential for more accurate, reliable, and repeatable ultrasonic experiments. If the scanner are modified to meet to appropriate purposes, it can be applied to automation of ultrasonic examination of nuclear power plants and helpful to the research on ultrasonic characterization of the materials.

• Journal of KIISE
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• v.44 no.2
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• pp.208-212
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• 2017

Flash SSDs have many advantages over the existing hard disks such as energy efficiency, shock resistance, and high I/O throughput. For these reasons, in combination with the emergence of innovative technologies such as 3D-NAND and V-NAND for cheaper cost-per-byte, flash SSDs have been rapidly replacing hard disks in many areas. However, the existing database engines, which have been developed mainly assuming hard disks as the storage, could not fully exploit the characteristics of flash SSDs (e.g. internal parallelism). In this paper, in order to utilize the internal parallelism intrinsic to modern flash SSDs for faster query processing, we implemented a prefetching method using asynchronous input/output as a new functionality for secondary index scans in MySQL InnoDB engine. Compared to the original InnoDB engine, the proposed prefetching-based scan scheme shows three-fold higher performance in the case of 16KB-page sizes, and about 4.2-fold higher performance in the case of 4KB-page sizes.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.1
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• pp.57-62
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• 1999

Polycrystaline thin film transistors are fabricated on the transparent glass substrate by a lamp-scan annealing. The line-shaped lamp scanning method, which is profitable for large area process, effectively radiated silicon film on glass substrate. Amorphous silion film absorbs the light which is emitted from halogen-lamp and it transformed into crystalline silicon by metal-induced lateral crystallization. In order to enhance the annealing effect, capping layer was deposited on the whole substrate. When the scan speed was 1-2mm/sec, lateral crystallization of amorphous silicon under capping layer was 18~27${\mu}m/scan$. The thin film transistor fabricated by this method shows high electron mobility over 130$cm^2/V{\cdot}sec$

• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.89-94
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• 2020

This paper proposes a better shielding method to over sampling technique. The new method uses aluminum foil for RF shielding. As a result of the phantom test, when the over-sampling technique was applied, the aliasing artifact was reduced by about 94% compared to before the application, and the case where the aluminum shielding band was applied was also reduced by about 92% compared to before application. In addition, the scan time also increased by more than 3 times in the case of the over-sampling technique, while it was found that there was no change from before the application of the aluminum shielding band Therefore, it was confirmed that the shielding band using aluminum foil can effectively remove aliasing artifacts without increasing the scan time..

• The Journal of Advanced Prosthodontics
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• v.4 no.3
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• pp.153-157
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• 2012

PURPOSE. The study was conducted to compare the radiographic and clinical methods of measuring the horizontal condylar guidance (HCG) values. MATERIALS AND METHODS. The condylar guidance was measured using the radiographic (CT scan) and three clinical methods i.e. the wax protrusive records, Lucia jig record and intraoral central bearing device in 12 patients aged between 20-40 years irrespective of sex. The records were taken and transferred on the semi-adjustable articulator to record the HCG values. The CT scan was taken for 3D reconstruction of the mid facial region. Frankfort horizontal plane (FHP) and a line extending from the superior anterior most point on the glenoid fossa to the most convex point on the apex of articular eminence (AE) was marked on the CT scan. An angle between these two lines was measured on both right and left sides to obtain condylar inclination angle. Three interocclusal protrusive wax and jig records were taken and transferred to the semi adjustable articulator. Three readings were recorded on each side. Similarly the records were taken and transferred to the same articulator using the intra oral central bearing device to record the readings. RESULTS. The statistical analysis showed insignificant differences in the HCG values between the right and left sides [(P=.589 (CT), P=.928 (wax), P=.625 (jig), P=.886 (tracer)]. The clinical methods provided low Pearsons correlation values [(R = 0.423 (wax), R = 0.354 (jig), R = 0.265 (tracer)] for the right as well as the left sides when compared with the CT values. Among the clinical methods, jig and wax method showed strong level of association which is statistically significant while the intra-oral tracer showed weak association with the other two methods. CONCLUSION. The right and left HCG values were almost similar. The CT scan showed higher HCG values than the clinical methods and among the clinical methods, values obtained from all the methods were comparable.

• The Korean Journal of Nuclear Medicine
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• v.21 no.2
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• pp.151-154
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• 1987

Total 114 patients were studied prospectively with radioiodine uptake (RAIU) and $^{99m}TcO_4^-$ thyroid scan to design a very simple, rapid and inexpensive method measuring the thyroid uptake on thyroid scan. After the RAIU was obtained at 24 hours after P.O. of $^{131}I$, Thyroid scan was performed at 20 minutes after LV. of $^{99m}TcO_4^-$ and the bilateral salivary glands were included in the scan field. Pinhole collimated and computer assisted gamma camera was used. Three regions of interest were set on each salivary gland and on the thyroid by automatic edge detection method. Mean counts per pixel were calculated for each ROI and the salivary-thyroid ratio (STR) was defined as; $$STR(%)=\frac{Mean\;counts\;per\;pixel\;of\;salivary\;glands\;(KC)}{Mean\;counts\;per\;pixel\;of\;thyroid\;gland\;(KC)}\times100$$ 114 cases consisted of 41 normal, 55 hyperthyroid and 18 hypothyroid patients and correlation between the STR and the RAID were evaluated in total and each group. The STR and the RAID showed reverse linear regression in 114 cases (r= -0.8, P=0) and closer correlation was shown in hyperthyroid group (r= -0_9, p=0). Mean STR in normal group was 47.6%. In predicting the RAID by STR, sensitivity and specificity were 88.3% and 64.9% in 114 cases and 95.3% and 83.3% in hyperthyroid group. It is recommended that the STR be used in place of the RAID giving same information at saving time, money and radiation exposure.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.203-209
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• 2003

In this study, the configuration and tension of a towing cable for side-scan sonar are predicted in an ambient flow and at an unsteady towing condition. The governing equation of three-dimensional dynamic analysis for a flexible cable is solved using a finite difference method. We successfully predict the configuration and tension of a side-scan sonar and designed the towing system. It is found in static analyses that the side-scan sonar must be towed to keep a its stable depth at a reasonable speed. The study also reveals in the transient analyses that the dominant component affecting the top tension is the tangential drag force for the larger towing speed than the critical speed, and the soft weight of a towed instrument for the smaller towing speed than. It should be maneuvered for a towing vessel with good consideration for the impact effect in a cable due to tension peak when a towing speed is suddenly increase. The developed program can be applicable for three-dimensional dynamic analysis of a towing system for various marine survey instruments.

• Interaction and multiscale mechanics
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• v.3 no.2
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• pp.173-191
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• 2010

Damage detection plays a very important role to the maintenance of bridge structures. Traditional damage detection methods are usually based on structural dynamic properties, which are acquired from pre-installed sensors on the bridge. This is not only time-consuming and costly, but also suffers from poor sensitivity to damage if only natural frequencies and mode shapes are concerned in a noisy environment. Recently, the idea of using the dynamic responses of a passing vehicle shows a convenient and economical way for damage detection of bridge structures. Inspired by this new idea and the well-established tap test in the field of non-destructive testing, this paper proposes a new method for obtaining the damage information through the acceleration of a passing vehicle enhanced by a tapping device. Since no finger-print is required of the intact structure, this method can be easily implemented in practice. The logistics of this method is illustrated by a vehicle-bridge interaction model, along with the sensitivity analysis presented in detail. The validity of the method is proved by some numerical examples, and remarks are given concerning the potential implementation of the method as well as the directions for future research.