• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.3
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• pp.9-17
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• 2000

In this paper we implement computer simulation system of 4FSK signal MODEM using Quadrature detector and analyze overall tranceiver system. We follow the FLEX wireless paging system standards and construct premodulation filter and data frame. We propose an efficient open loop symbol timing recovery algorithm which takes advantage of 128 bit length preamble pattern and also propose a 32 bit UW pattern which Is based on the optimal UW detection method, and excellent aperiodic autocorrelation characteristic. The BER simulation in the fading channel as well as AWGN is performed with BCH coding and Interleaving to the Quadrature detector system and it is shown that a high coding fain occurs in the fading channel rather than AWGN channel.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.1
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• pp.1-11
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• 2002

This study set up a purpose in the efficient utilization of security target objects. This purpose is the following: Firstly, this study analyzed problem about deleted areas for security described on aerial photography image. Secondly, this study made clustering and labeling to recognize censored areas of image. Finally, this study tried to maximize various utilizability of digital image data through postprocessing algorithm. Based on these courses, the results of this study appeared that brightness value of image increased depending on topography and quantities of topographic features. It was estimated that these was able to utilized by useful estimative data in judging information of topography and topographic features included in the total image. Besides, in the image recognition and postprocessing, the better result value was not elicited than in a mountainous region. Because it was included that a lots of topography and topographic features was similarly recognized with the process for deletion of the existing security target objects in urban and suburb region. This result appeared that the topography and quantities of topographic features absolutely affected the recognition and processing of image.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.5
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• pp.987-999
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• 2014

A PUF is embedded and implemented into a tag or a device, and outputs a noise y with an input of x, based on its own unique physical characteristics. Although x is used multiple times as inputs of PUF, the PUF outputs slightly different noises, ($y_1,{\cdots}y_n$), and also the PUF has tamper-resistance property, hence it has been widely used in cryptographic protocol. In this paper, we study how to design a PUF-based RFID authentication protocol in a secure and an efficient way. Compared with recent schemes, the proposed scheme guarantees both authentication and privacy of backword/forward under the compromise of long-term secrets stored in tag. And also, the most cost and time-consumming procedure, key recovery algorithm used with PUF, has been desgined in the side of RFID reader, not in the tag, and, consequently, gives possibility to minimize costs for implementation and running time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.8
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• pp.1765-1773
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• 1997

The communication systems which include PLL may have cycle clip problem because of channel noise. The cycle slip problem occurs the synchronization loss of communication system and it may be fatal to the synchronous stream cipher system. While continuous resynchronization is used to lessen the risk of synchronization it has some problems. In this paper, we propose the method which solve the problems by using continuous resynchronization with the clock recovery technique. If the counted value of real clock pulse in reference duration is not same as that of normal state, we decide the cycle slip has occurred. The damaged clock by cycle slip is compensated by adding or subtracting the clock pulse according to the type of cycle slip. It reduced the time for resynchronization by twenty times. It means that 17.8% of data for transmit is compressed.

• The KIPS Transactions:PartB
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• v.9B no.5
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• pp.563-570
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• 2002

Robust extraction of 3D facial features and global motion information from 2D image sequence for the MPEG-4 SNHC face model encoding is described. The facial regions are detected from image sequence using multi-modal fusion technique that combines range, color and motion information. 23 facial features among the MPEG-4 FDP (Face Definition Parameters) are extracted automatically inside the facial region using color transform (GSCD, BWCD) and morphological processing. The extracted facial features are used to recover the 3D shape and global motion of the object using paraperspective camera model and SVD (Singular Value Decomposition) factorization method. A 3D synthetic object is designed and tested to show the performance of proposed algorithm. The recovered 3D motion information is transformed into global motion parameters of FAP (Face Animation Parameters) of the MPEG-4 to synchronize a generic face model with a real face.

• Journal of Digital Convergence
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• v.19 no.12
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• pp.145-150
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• 2021

In order to continuously perform quarantine in public places, it is not easy to secure manpower, but using self-driving-based robots can solve problems caused by manpower. Self-driving-based quarantine robots can continuously prevent the spread of harmful viruses and diseases in public institutions and hospitals without additional manpower. The location of the autonomous driving function was estimated by applying the Pinnacle filter algorithm, and the UV sterilization system and chlorine dioxide injection system were applied for quarantine. The driving time is more than 3 hours and the position error is 0.5m.Soon, the stop-avoidance function was operated at 95% and the obstacle detection distance was 1.5 m, and the automatic charge recovery was charged by moving to the charging cradle at the remaining 10% of the battery capacity. As a result of quarantine with an unmanned quarantine system, UV sterilization is 99% and chlorine dioxide is sterilized more than 95%, which can contribute to reducing enormous social costs.

• Korean Journal of Heritage: History & Science
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• v.50 no.2
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• pp.80-93
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• 2017

This study proposes a new scientific measurement method for damaged epigraph. In this new method, the Chinese characters are converted and coordinates are created for this measurement. This method is then used to decipher partially damaged characters from the parts of the coordinated characters that are damaged and intact. The Chinese characters are divided into 9 square parts by the position of their Chinese Radicals. The unknown characters are then compared and deciphered dependent upon the character shape in 9 square parts that have been created. This method is more scientific, accurate, and makes it easier to find related characters than deciphering through contexts, which is current method. When creating a new software based on this algorithm, it will be especially useful in deciphering an old manuscript or a epigraph that made ancient Chinese characters which are not currently in use. This study will also be helpful in deciphering semi-cursive styled or cursive styled epigraph, as well as semi-cursive styled or cursive styled damaged characters during follow-up research.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.4
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• pp.93-102
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• 2019

As interest in wellness grows, There is a lot of research about monitoring individual health using wearable devices. Accordingly, a variety of methods have been studied to distinguish exercise from daily activities using wearable devices. Most of these existing studies are machine learning methods. However, there are problems with over-fitting on individual person's learning, data discontinuously recognition by independent segmenting and fake activity. This paper suggests a detection method for exercise activity based on the physiological response principle of heart rate up and down during exercise. This proposed method calculates activity intensity and heart rate from triaxial and photoplethysmography sensor to determine a heart rate recovery, then detects exercise by estimating activity intensity or detecting a heart rate rising state. Experimental results show that our proposed algorithm has 98.64% of averaged accuracy, 98.05% of averaged precision and 98.62% of averaged recall.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.1
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• pp.29-40
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• 2005

In this paper we consider the security of recently proposed software-orienred stram cipher HELIX, SCREAM, MUGI, and PANAMA against algebraic attacks. Algebraic attack is a key recovery attack by solving an over-defined system of multi-variate equations with input-output pairs of an algorithm. The attack was firstly applied to block ciphers with some algebraic properties and then it has been mon usefully applied to stream ciphers. However it is difficult to obtain over-defined algebraic equations for a given cryptosystem in general. Here we analyze recently proposed software-oriented stream ciphers by constructing a system of equations for each cipher. furthermore we propose three design considerations of software-oriented stream ciphers.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.779-790
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• 2022

Fuzzy extractor is a biometric encryption that generates keys from biometric data where input values are not always the same due to the noisy data, and performs authentication securely without exposing biometric information. However, if a user registers biometric data on multiple servers, various attacks on helper data which is a public information used to extract keys during the authentication process of the fuzzy extractor can expose the keys. Therefore many studies have been conducted on reusable fuzzy extractors that are secure to register biometric data of the same person on multiple servers. But as the key length increases, the studies presented so far have gradually increased the number of key recovery processes, making it inefficient and difficult to utilize in security systems. In this paper, we design an efficient and reusable fuzzy extractor based on LWE with the same or similar number of times of the authentication process even if the key length is increased, and show that the proposed algorithm is reusably-secure defined by Apon et al.[5].