• Imaging Science in Dentistry
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• v.44 no.1
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• pp.31-35
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• 2014

Purpose: This study was performed to investigate the effect of image enhancement of periapical radiographs according to the diagnostic task. Materials and Methods: Eighty digital intraoral radiographs were obtained from patients and classified into four groups according to the diagnostic tasks of dental caries, periodontal diseases, periapical lesions, and endodontic files. All images were enhanced differently by using five processing techniques. Three radiologists blindly compared the subjective image quality of the original images and the processed images using a 5-point scale. Results: There were significant differences between the image quality of the processed images and that of the original images (P< 0.01) in all the diagnostic task groups. Processing techniques showed significantly different efficacy according to the diagnostic task (P< 0.01). Conclusion: Image enhancement affects the image quality differently depending on the diagnostic task. And the use of optimal parameters is important for each diagnostic task.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.244-249
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• 1998

In this paper, the hybrid state space self-tuning control technique Is studied within the framework of fuzzy systems and dual-rate sampling control theory. We show that fuzzy modeling techniques can be used to formulate chaotic dynamical systems. Then, we develop the hybrid state space self-tuning fuzzy control techniques with dual-rate sampling for digital control of chaotic systems. An equivalent fast-rate discrete-time state-space model of the continuous-time system is constructed by using fuzzy inference systems. To obtain the continuous-time optimal state feedback gains, the constructed discrete-time fuzzy system is converted into a continuous-time system. The developed optimal continuous-time control law is then convened into an equivalent slow-rate digital control law using the proposed digital redesign method. The proposed technique enables us to systematically and effective]y carry out framework for modeling and control of chaotic systems. The proposed method has been successfully applied for controlling the chaotic trajectories of Chua's circuit.

• Journal of IKEEE
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• v.19 no.2
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• pp.176-185
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• 2015

The study aims to a design hybrid frequency synthesizer in spectrum analyzer and to propose new techniques designed for evasion of in-band spurious. The study focuses on calculating the exact location of multiple phase locked loop of hybrid frequency synthesizer and spurious of direct digital synthesizer to evade in-band spurious outside of frequency range that the user wants to see and thereby simulating technique to improve input related spurious of spectrum analyzer for algorithm. The proposed technique is designed to calculate spurious evasion algorithm in central processing system when in-band spurious arises, and to move output frequency of DDS(direct digital synthesizer) into the place where no in-band spurious exists thereby improving performance of frequency synthesizer. The study used simulation and result representation to prove the effectiveness of the proposed technique.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.939-942
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• 2003

Design verification problem is emerging as an important issue to detect any design errors at the early stage of the design. Conventionally, design verifications have been done using a simulation technique. However, this technique has been proved not to cover all potential design errors. Therefore, formal technique is often used to verify digital circuits as an alternative. In this paper we adopted formal verification technique and verified some important properties derived from our pipelined digital systems, using SMV (Symbolic Model Verifier). Our example shows that model checking method (one of formal verification techniques) can be effectively performed in verifying the large digital systems.

• Applied Microscopy
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• v.45 no.2
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• pp.101-105
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• 2015

Numerous digital image analysis techniques have been developed with regard to transmission electron microscopy (TEM) with the help of programming. DigitalMicrograph (DM, Gatan Inc., USA), which is installed on most TEMs as operational software, includes a script language to develop customized software for image analysis. Based on the DM script language, this work provides a script source listing for quantitative strain measurements based on a geometric phase analysis.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.144-144
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• 2002

Analysis techniques using stereo-photos of object is used widely in close-range-photogrammetry field. but, there is difficulty to use metric camera for specialist. In this study, stereo images were acquired using metric camera and general digital camera about slide in Youngdong area. And they were generated two DEMs based metric camera and digital camera. And it was analyzed the correlation of two DEMs. Therefore, in research that was presented effectiveness of digital camera take the place of metric camera for slope analysis.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1540-1542
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• 2005

In SMPS, digital control techniques are adopted widely. But Digital controlled SMPS has poor performance of regulation and transient response than analog controlled SMPS. Delay time of control computing and low frequency of updating duty ratio make digital controlled SMPS poor performance. This paper proposed the optimized control computation to increase not only frequency of updating duty ratio but also switching frequency of SMPS.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.914-916
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• 2003

Most current 3D digital maps are 2.5 dimension models based on DEM, which can only be recognized, browsed and operated by a special software, far from meeting the needs of a modern digital city (global) with the distributed, isomerous and multiple application on the real 3D representation and open sharing models. In this paper, a new generation digital city oriented 3D digital map is studied. Firstly, a real 3D digital map representation is presented. And then, some key techniques and methods for browser-based 3D digital map’s representation, display and operation are introduced, which can realized the open sharing of 3D map in distributed, isomerous and multiple application environment. Furthermore, the scale driving technique of proposed 3D digital map is also studied. And currently, some developments based on some of the above methods are being carried to provide key and general platform for other application software’s development.

• Convergence Security Journal
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• v.13 no.6
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• pp.25-33
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• 2013

Digital certificate must be used for electronic financial transactions in Korea. But because digital certificate is based ActiveX of Internet Explorer, it is difficult to use digital certificate in other web browsers. It interrupts a development of various authentication technology and a growth of related industry. Also digital certificate can be leaked because of being stored in harddisk or USB. The government eased obligatory use of digital certificate and opened doors to other authentication techniques. But any other authentication techniques are not used because they are not approved as alternative technology. The revised bills with digital certificate abolition as the main agenda have been submitted to the National Assembly. Whether the revised bills pass or not will be decided by a regular session of the National Assembly depending on the calculation and dynamics composition of related industry. In this paper, a controversy over obligatory use of digital certificate is examined and measures are found.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1886-1898
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• 2015

In today’s era of advanced technological developments, the threats to the authenticity and integrity of digital images, in a nutshell, the threats to the Image Forensics Research communities have also increased proportionately. This happened as even for the ‘non-expert’ forgers, the availability of image processing tools has become a cakewalk. This image forgery poses a great problem for judicial authorities in any context of trade and commerce. Block matching based image cloning detection system is widely researched over the last 2-3 decades but this was discouraged by higher computational complexity and more time requirement at the algorithm level. Thus, for reducing time need, various dimension reduction techniques have been employed. Since a single technique cannot cope up with all the transformations like addition of noise, blurring, intensity variation, etc. we employ multiple techniques to a single image. In this paper, we have used Fuzzy logic approach for decision making and getting a global response of all the techniques, since their individual outputs depend on various parameters. Experimental results have given enthusiastic elicitations as regards various transformations to the digital image. Hence this paper proposes Fuzzy based cloning detection and classification system. Experimental results have shown that our detection system achieves classification accuracy of 94.12%. Detection accuracy (DAR) while in case of 81×81 sized copied portion the maximum accuracy achieved is 99.17% as regards subjection to transformations like Blurring, Intensity Variation and Gaussian Noise Addition.