• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.261-267
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• 2004

In undeniable digital signature scheme, the signature can not be verified without the signer's cooperation. The undeniable signature scheme can be used to computerize many applications which can not be done by a conventional digital signature scheme. In this study, we propose the undeniable digital multi-signature scheme which requires many signers and designated verifier. The multi-signature can be verified only in cooperation with all signers. The proposed scheme satisfies undeniable property and it is secure against active attacks such as modification and denial of the multi-signature by signers. We also discuss practical applications such as joint copyright protection on digital contents.

• Asian Journal of Innovation and Policy
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• v.5 no.2
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• pp.185-196
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• 2016

A digital cable broadcasting service is a multimedia broadcasting service that provides high definition and various supplementary services by using digital transmission. Korea implemented a complete digital broadcasting service by 2012. This study applied a choice experiment to investigate consumer preferences, and it calculated the marginal willingness to pay for this service. Moreover, we employed a multinomial probit model to relax the assumption that all respondents have the same preference for attributes being valued. The results suggest that respondents value channels, definition, video-on-demand (VOD) service, pay-per-view (PPV) service, and commerce based on TV (T-commerce). On the other hand, online gaming may be less important as an attribute for digital cable broadcasting service in Korea.

• Journal of information and communication convergence engineering
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• v.11 no.4
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• pp.282-287
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• 2013

A real-time digital holographic display is the core technology for the next-generation 3DTV. Holographic display requires a considerably large amount of calculation. If generating a large number of digital holograms is intended, the amount of calculation and the time required increase exponentially. This is a significant obstacle in a real-time hologram service. This paper proposes an algorithm that increases the speed of generating a Fresnel hologram by using a recursive addition operation covering the entire coordinate array of a digital hologram. The 3D object designed to calculate the digital hologram uses a depth-map image produced by computer graphics. The proposed algorithm is a technique that performs the computer-generated holography (CGH) operation with only recursive addition of all of the hologram's coordinates by analyzing the regularity between the 3D object and the digital hologram coordinates. The experimental results show that the proposed algorithm increases the operation speed by 70% over the technique using the conventional CGH equation and by more than 30% over the previously proposed recursive technique.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2001.05a
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• pp.100-105
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• 2001

The space in today's digital era is developing in a new direction with the changing paradigm, which is different from that in the analog era. The space that appeals to the advanced technology mobilizes all the five senses of the space user with the technical elements of the more variable fields and aesthetic productions, and creates an interactive environment by motivating the user's active participation through the digital media. The environmental device called digital media connects the function pace with living performance. Unlike in the analog space, the different sides of the digital media space create a human consciousness that corresponds to the realistic ambience, further contributing to the lively condition. For the main production technique in the digital medias performance-active space, there are electronic image production, changeable production, impromptu-active production, light and sound production, and total artistic production that lead to the progressive interaction between man and space.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.859-861
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• 2003

In order to present a space in details, it is indispensable to acquire 3D shape and texture simultaneously from the same platform. 3D shape is acquired by Laser Scanner as point cloud data, and texture is acquired by CCD sensor. Positioning data is acquired by IMU (Inertial Measurement Unit). All the sensors and equipments are assembled on a hand-trolley. In this research, a method of integrating the 3D shape and texture for automated construction of Digital Surface Model is developed. This Digital Surface Model is applied for efficient feature extraction. More detailed extraction is possible , because 3D Digital Surface Model has both 3D shape and texture information.

• Imaging Science in Dentistry
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• v.50 no.1
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• pp.53-64
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• 2020

Purpose: The aim of this study was to determine the prevalence of incidental findings(IFs) on digital dental panoramic radiographs(DPRs) of asymptomatic patients attending a general dental practice. Materials and Methods: This was a retrospective study of 6,252 consecutive digital (photostimulatable phosphor) DPRs of patients who visited a Canadian general dental practice for a complete new patient examination. The IFs were grouped into dental-related anomalies, radiopacities and radiopacities in the jaws, changes in the shape of the condyles, and other findings in the jaws, such as tonsilloliths and mucosal antral pseudocysts. Their prevalence was determined. Results: Thirty-two percent of the DPRs showed at least 1 IF. The highest prevalence was found for dental-related anomalies(29% of all DPRs), of which impacted teeth were the most prevalent finding (24% of all DPRs), followed by idiopathic osteosclerosis(6% of all DPRs). A lower prevalence was noted for tonsilloliths(3%), and the prevalence of root tips, mucosal antral pseudocysts, and anomalies in condylar shape was approximately 1% each. Conclusion: The observed prevalence of 32.1% for IFs of any type underscores the need for a dental practitioner to review the entire DPR when a patient presents for an initial dental examination (or check-up) or for dental hygiene. Only a single IF (a central giant cell granuloma) provoked alarm, as it was initially considered malignant. Similarly, impacted teeth and suspected cysts need careful evaluation upon discovery to determine how they may be optimally managed.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.66.1-66.1
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• 2012

Although all printed cost-less radio frequency identification (RFID) tags have been considered as a core tool for bringing up a ubiquitous society, the difficulties in integrating thin film transistors (TFTs), diodes and capacitors on plastic foils using a single in-line printing method nullify their roles for the realization of the ubiquitous society1,2. To prove the concept of all printed cost-less RFID tag, the practical degree of the integration of those devices on the plastic foils should be successfully printed to demonstrate multi bit RFID tag. The tag contains key device units such as 13.56 MHz modulating TFT, digital logic gates and 13.56 MHz rectifier to generate and transfer multi bit digital codes via a wireless communication (13.56 MHz). However, those key devices have never been integrated on the plastic foils using printing method yet because the electrical fluctuation of fully printed TFTs and diodes on plastic foils could not be controlled to show the function of desired devices. In this work, fully gravure printing process in printing 13.56 MHz operated 32 bit RFID tags on plastic foils has been demonstrated for the first time to prove all printed RFID tags on plastic foils can wirelessly generate and transfer 32 bit digital codes using the radio frequency of 13.56 MHz. This result proved that the electrical fluctuations of printed TFTs and diodes on plastic foils should be controlled in the range of maximum 20% to properly operate 32 bit RFID tags.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1987.04a
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• pp.82-85
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• 1987

This paper describes the technology for the improvement of subxdriber loop utilization. Nearly all customer loops are now carried at voice frequency on individual wire pairs. Reenct digital technology improvements together with the increasing cost of wire, have resulted in some penetration of carrier systems into the loop plant. Moreover the increasing use of local digital switching systems should permit digital carrier systems to become an important factor in the loop plant in the future.

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.323-324
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• 2009

In this paper, we use multi-point sources to illuminate the sample in digital holographic microscopy. The resolution of digital holographic microscopy is enhanced without shifting the CCD camera. The specimen is illuminated from many directions by using multi-point sources which are easily created by a lens-array. The high frequency information of specimen can be captured at a fixed position of CCD camera. All information is then synthesized to increase the resolution.

• Journal of Electrical Engineering and information Science
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• v.3 no.2
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• pp.139-144
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• 1998

This paper describes the design of a variable rate QPSK demodulator for digital satellite TV system. This true variable-rate demodulator employs a unique architecture to realize an all digital synchronization and detection algorithm. Data-flow based design approach enabled a seamless transition from high level design optimization to physical layout. The demodulator has been integrated with Viterbi decoder, de-interleaver, and Ree-Solomon decoder to make a single chip Digital Video Broadcast (DVB) receiver. The receiver IC has been fabricated with a 0.5mm CMOS TLM process and proved fully functional in a real-world set-up.