• Imaging Science in Dentistry
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• v.45 no.2
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• pp.81-87
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• 2015

Purpose: Contrast, sharpness, enhancement, and density can be changed in digital systems. The important question is to what extent the changes in these variables affect the accuracy of caries detection. Materials and Methods: Forty eight extracted human posterior teeth with healthy or proximal caries surfaces were imaged using a photostimulable phosphor (PSP) sensor. All original images were processed using a six-step method: (1) applying "Sharpening 2" and "Noise Reduction" processing options to the original images; (2) applying the "Magnification 1:3" option to the image obtained in the first step; (3) enhancing the original images by using the "Diagonal/"option; (4) reviewing the changes brought about by the third step of image processing and then, applying "Magnification 1:3"; (5) applying "Sharpening UM" to the original images; and (6) analyzing the changes brought about by the fifth step of image processing, and finally, applying "Magnification 1:3." Three observers evaluated the images. The tooth sections were evaluated histologically as the gold standard. The diagnostic accuracy of the observers was compared using a chi-squared test. Results: The accuracy levels irrespective of the image processing method ranged from weak (18.8%) to intermediate (54.2%), but the highest accuracy was achieved at the sixth image processing step. The overall diagnostic accuracy level showed a statistically significant difference (p=0.0001). Conclusion: This study shows that the application of "Sharpening UM" along with the "Magnification 1:3" processing option improved the diagnostic accuracy and the observer agreement more effectively than the other processing procedures.

• Proceedings of the Technology Innovation Conference
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• 2005.02a
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• pp.124-139
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• 2005

In the early stage, the radio communication industry was widely accepted as a monopoly industry, so it has been controled and managed by government. But the advanced technology in Information and Technology industry has led constant increase of demand and dramatic change of communication market. Furthermore it is expected that frequency resource is to be short by market change due to wire-wireless integration. That is why the effort to utilize and manage limited frequency resource efficiently is being executed around the world. Not only newly developing and allocating the spectrum but also reallocating the existing spectrum important are, since transforming inefficiently used existing spectrum to new service can increase producer's surplus and social welfare. The economic approach to valuate the spectrum and spectrum usage right is necessary different from the traditional cost based approach, and through this approach I expect active transaction of spectrum. In this paper the real option methodology is used for valuation of spectrum, considering spectrum user's option right based on future revenue. In detail, the matter of withdrawing and reallocating the existing analog radio broadcasting spectrum is evaluated in this paper, The digitalization of a broadcasting service is widely spreaded around the world in terms of technology and service utility, and analog TV broadcasting has already been decided to be transformed to digital TV broadcasting. It was planned to convert analog radio broadcasting to DAB service before adopting DMB service, but nowadays this issue is not on the table anymore. However if the increasing demand of digital voice and broadcasting service is considered, this kind of research to valuate a spectrum is needed urgently. The result of this research shows that when the redeployment of spectrum is done, social welfare will increases. The point of the reallocation time and value are suggested by the monte carlo simulation through ROVM. In this paper, I use real option to valuate the spectrum and provide the point of the reallocation time and reasonable guideline, and moreover, the suitable information of this paper is expected to reduce risk and loss in policy practice.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.634-636
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• 1995

This paper presents a new distance relay modeling techniques which avoids unnecessary computational procedure. A general-purpose simulation language, called MODELS, has been added to the software ATP(Alternative Transients Program) providing a new option to perform numerical and logical manipulations of variables of an electrical system. This language has been designed to replace the previous option TACS (Transient Analysis of Control Systems) which permits to simulate a control system in conjunction with a large power network. One purpose of this study is to build a structure for modeling of digital distance relays within EMTP MODELS. Contrary to the traditional methods, the new method using MODELS reduce the number of simulation steps in modeling the distance relay.

• Archives of Reconstructive Microsurgery
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• v.7 no.2
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• pp.108-113
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• 1998

Reverse digital artery flaps were performed successfully to resurface the fingertip defect in 13 patients as noninnervated pattern and in 12 patients as innervated pattern from March 1993 to February 1996. No loss of flap in this series was noted. Refinements in flap design and surgical technique resulted in favourable functional and ethetic results. The average two-point discrimination of the reconstructed fingertip was 7.2mm and 4.5mm in the noninnervated and innervated flaps, respectively. This flap is an one of the ideal and reliable option for reconstruction of fingertip defects.

• Journal of Power Electronics
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• v.19 no.3
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• pp.613-624
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• 2019

Digital current control techniques are an attractive option for DC-DC converters. In this paper, a digital predictive peak current control algorithm is presented for buck converters that allows the inductor current to track the reference current in two switching cycles. This control algorithm predicts the inductor current in a future period by sampling the input voltage, output voltage and inductor current of the current period, which overcomes the problem of hardware periodic delay. Under the premise of ensuring the stability of the system, the response speed is greatly improved. A real-time parameter identification method is also proposed to obtain the precision coefficient of the control algorithm when the inductance is changed. The combination of the two algorithms achieves adaptive tracking of the peak inductor current. The performance of the proposed algorithms is verified using simulations and experimental results. In addition, its performance is compared with that of a conventional proportional-integral (PI) algorithm.

• Journal of Digital Convergence
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• v.16 no.5
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• pp.33-42
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• 2018

This paper is based on the suggestions of the prior research on the buyer feedback, the selection of various product options, and the payment procedure improvements for Korea ON-line E-Procurement System(KONEPS), and this is to confirm the necessity of improvement and satisfaction from the viewpoint of the workers of the public and subordinate organizations the purchasing and using of the computer equipment in the actual KONEPS(Korea ON-line E-Procurement System). Based on the basic questionnaires and in-depth interviews, this paper conducts the qualitative case studies on IT and non - IT workers who had purchasing experiences for equipment at public institutions and government agencies in Gyeongbuk province. As results of the study, it was confirmed that the improvement is necessary for the buyer feedback and option selection part, and that there is a difference among the work experience for the simplification of the payment procedure and the satisfaction. In addition, the biggest contribution in the provided research is to categorize and to analyze the opinions on the use of public and relevant subordinate research participants. Additional work will be needed for a large number of workers in public and subordinate organizations who have purchasing experiences for handling various procurement products and those working in the metropolitan area and other public and subordinate agencies.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.107-107
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• 2003

GPS Receiver는 위성에 위치 정보와 시간 정보등을 제공하고 navigation을 관리하며 이에 관련된 signal을 processing하는 역할을 한다. 2005년에 발사 예정인 KOMPSAT-2 위성에는 Alcatel에서 제작된 Topstar 3000이 사용된다. Topstar 3000은 RF 부분과 digital 처리부분으로 구성된 GPS core부분과 MLD-STD_1553, DC-DC converter, 그리고 Ovened-controlled Oscillator(OCXO)부분으로 구성되는 option module 부분으로 구성되어 있다. 본 논문에서는 GPS Signal Simulator로 KOMPSAT-2의 실제 궤도를 구현해서 Sun-Point Mode와 Earth-Point Mode 등 여러가지 Mode 에서 GPS Receiver의 시간, 위치, 속도 정보의 정확성에 대한 성능이 분석된다.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.4
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• pp.205-210
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• 2003

A 3-Transistor cell CMOS OTP ROM array using standard CMOS antifuse (AF) based on permanent breakdown of MOSFET gate oxide is proposed, fabricated and characterized. The proposed 3-T OTP cell for ROM array is composed of an nMOS AF, a high voltage (HV) blocking nMOS, and cell access transistor, all compatible with standard CMOS technology. The experimental results show that the proposed structure can be a viable technology option as a high density OTP ROM array for modern digital as well as analog circuits.

• Imaging Science in Dentistry
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• v.43 no.3
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• pp.185-190
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• 2013

Purpose: The aim of the present study was to evaluate the measurement accuracy of endodontic file length on periapical digital radiography after application of noise reduction digital enhancement. Materials and Methods: Thirty-five human single-rooted permanent teeth with canals measuring 20-24 mm in length were selected. ISO #08 endodontic files were placed in the root canals of the teeth. The file lengths were measured with a digital caliper as the standard value. Standard periapical digital images were obtained using the Digora digital radiographic system and a dental X-ray unit. In order to produce the enhanced images, the noise reduction option was applied. Two blinded radiologists measured the file lengths on the original and enhanced images. The measurements were compared by repeated measures ANOVA and the Bonferroni test (${\alpha}=0.05$). Results: Both the original and enhanced digital images provided significantly longer measurements compared with the standard value (P<0.05). There were no significant differences between the measurement accuracy of the original and enhanced images (P>0.05). Conclusion: Noise reduction digital enhancement did not influence the measurement accuracy of the length of the thin endodontic files on the digital periapical radiographs despite the fact that noise reduction could result in the elimination of fine details of the images.

• Archives of Reconstructive Microsurgery
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• v.18 no.2
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• pp.79-83
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• 2009

Purpose: Avulsion injuries of digits have been presented for a long time as complex management problems. Despite of microsurgical advances, it is difficult to achieve good functional results and their management remains somewhat controversial. However, in a finger there are three transverse digital palmar arches. The middle and distal transverse digital palmar arches are consistently large(almost 1 mm) and may be used for arterial vessel repairs either proximally or distally, depending on the length and direction needed. 39-year-old man presented with avulsion amputation of the ulnar three digits, was operated using only arterial anastomosis with rerouting the transverse digital palmar arches. Methods: Replantation was performed using the artery-only technique. Because the digital arteries had been damaged, we did that the transverse digital palmar arches were transposed in an inverted Y to I configuration and were lengthened with rerouting them for the purpose of direct anastomosis of the digital artery. Venous drainage was provided by an external bleeding method with partial nail excision and external heparin irrigation. Results: The authors conclude that complete avulsion amputations with only soft tissue at the distal to insertion of the flexor digitorum superficialis tendon were salvageable with acceptable functional results. All three fingers survived. Conclusion: With technical advancements, the transverse digital palmar arches play an important role for finger amputation. Three digital palmar arches give us additional treatment option for the finger amputation. In this case, replantation with only-arterial anastomosis was successful and we obtained good aesthetic and functional outcome.