• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.4
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• pp.739-747
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• 2015

Masking technique that is most widely known as countermeasure against power analysis attack prevents leakage for sensitive information during the implementations of cryptography algorithm. it have been studied extensively until now applied on block cipher algorithms. Masking countermeasure have been applied to international standard SEED algorithm. Masked SEED algorithm proposed by Cho et al, not only protects against first order power analysis attacks but also efficient by reducing the execution of Arithmetic to Boolean converting function. In this paper, we analyze the vulnerability of Cho's algorithm against first order power analysis attacks. We targeted additional pre-computation to improve the efficiency in order to recover the random mask value being exploited in first order power analysis attacks. We describe weakness by considering both theoretical and practical aspects and are expecting to apply on every device equipped with cho's algorithm using the proposed attack method.

• Journal of The Korean Astronomical Society
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• v.51 no.3
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• pp.65-71
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• 2018

The near real-time speckle masking reconstruction technique has been developed to accelerate the processing of solar images to achieve high resolutions for ground-based solar telescopes. However, the reconstruction of solar subimages in such a speckle reconstruction is very time-consuming. We design and implement a new parallel speckle masking reconstruction algorithm based on the Compute Unified Device Architecture (CUDA) on General Purpose Graphics Processing Units (GPGPU). Tests are performed to validate the correctness of our program on NVIDIA GPGPU. Details of several parallel reconstruction steps are presented, and the parallel implementation between various modules shows a significant speed increase compared to the previous serial implementations. In addition, we present a comparison of runtimes across serial programs, the OpenMP-based method, and the new parallel method. The new parallel method shows a clear advantage for large scale data processing, and a speedup of around 9 to 10 is achieved in reconstructing one solar subimage of $256{\times}256pixels$. The speedup performance of the new parallel method exceeds that of OpenMP-based method overall. We conclude that the new parallel method would be of value, and contribute to real-time reconstruction of an entire solar image.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.121-130
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• 2014

This paper is the second investigation on the effects of intake flow control methods on the part load performance in a spark ignition engine. In the previous work, two control methods, port throttling and masking, were compared with respect to lean misfire limit, fuel consumption and emissions. In this work, the effects of these two methods on EGR characteristics were studied and simultaneously the differences between EGR and lean combustion as a dilution method were investigated. The results show that EGR limit is expanded up to 23% and 3 ~ 5% improvement in the fuel consumption are achieved around 8 ~ 13% rates by the flow controls comparing with 10% limit and 1.5% reduction around 3% rate of non-control case. The masking method is more effective on the limit expansion than throttling as like as lean misfire limit; however there is no substantial difference in fuel consumptions improvement regardless the control methods except high load condition. Also it is observed that there exist critical EGR rates around which the combustion performance and NOx formation change remarkably and these rates generally coincide with optimum rates for the fuel consumption. In addition, dilution with fresh air is much more advantageous than that of the exhaust gas from the view point of dilution limit and fuel consumption, while utilization of the exhaust gas is more effective on NOx reduction in spite of considerably small dilution compared with the use of fresh air. Finally, the improvement of fuel consumption by massive EGR is highly dependent on the EGR limit at which the engine runs stably, therefore the stratified combustion technique might be a best solution for this purpose.

• The Korean Journal of Applied Statistics
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• v.34 no.2
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• pp.167-175
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• 2021

Semi-supervised learning uses both labeled data and unlabeled data. Recently consistency regularization is very popular in semi-supervised learning. Unsupervised data augmentation (UDA) that uses unlabeled data augmentation is also based on the consistency regularization. The Kullback-Leibler divergence is used for the loss of unlabeled data and cross-entropy for the loss of labeled data through UDA learning. UDA uses techniques such as training signal annealing (TSA) and confidence-based masking to promote performance. In this study, we propose to use Jensen-Shannon divergence instead of Kullback-Leibler divergence, reverse-TSA and not to use confidence-based masking for performance improvement. Through experiment, we show that the proposed technique yields better performance than those of UDA.

• IEMEK Journal of Embedded Systems and Applications
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• v.19 no.1
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• pp.19-25
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• 2024

This paper proposes an artificial intelligence-based personal information area object detection optimization method in an embedded system to de-identify personal information in video data. As an object detection optimization method, first, in order to increase the detection rate for personal information areas when detecting objects, a gyro sensor is used to collect the shooting angle of the image data when acquiring the image, and the image data is converted into a horizontal image through the collected shooting angle. Based on this, each learning model was created according to changes in the size of the image resolution of the learning data and changes in the learning method of the learning engine, and the effectiveness of the optimal learning model was selected and evaluated through an experimental method. As a de-identification method, a shuffling-based masking method was used, and double-key-based encryption of the masking information was used to prevent restoration by others. In order to reuse the original image, the original image could be restored through a security key. Through this, we were able to secure security for high personal information areas and improve usability through original image restoration. The research results of this paper are expected to contribute to industrial use of data without personal information leakage and to reducing the cost of personal information protection in industrial fields using video through de-identification of personal information areas included in video data.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1072-1075
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• 1996

In hot rolling process at steel plant, cooling of the rolled strip at the exit of the rolling mill is one of the most important processes that would decide the quality of products. To guarantee the thermal equity over the strip, the device called an edge-masking unit is being used. That is installed between the strip and the sprayers to cover the side edge of the strip from spraying water. The accuracy of positioning the bracket is the key to this operation. A machine vision technique can be applied to measure the position of the side edges before an as-rolled strip enters into the cooling facility to rectify the error of preset position of the bracket. This paper shows the simulation result of applying the machine vision technique to measuring the position of a strip and suggests the solution for the target.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.294-299
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• 2001

The old technique of sandblasting which has been used for decoration of glass surface has recently been developed into a powder blasting technique for various materials, capable of producing micro structures larger than 100 m. This paper describes the performance of powder blasting technique in micro-line grooving of glass and the effect of the number of nozzle scanning on the depth and width of line groove. Experimental results showed that increasing the no. of nozzle scanning resulted in the increase of depth and width in grooves. Increase of width which may cause several problems in the precision machining results from wear of mask film.

• Journal of Technologic Dentistry
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• v.22 no.1
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• pp.49-55
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• 2000

In manufacturing the all-ceramic crown whick look close to natural teeth, the effectiveness of the improved technique is expectected the technique of the heat treatment of gold plating coating die was experimented of a refractory cast model. The following results were obtainde 1. An advantage of build up on east die with out manufacturing veneer, crown, core, or masking(reduction of technical process, and retrenchment of time and money) 2. Esthetically more close to natural teeth than other technique 3. Easy to remove a refractors cast die 4. In manufacturing ceramo-metal crown the enomous effectiveness was obtainde on applying in the areas of cervical margin, the metal surface, and in the treatment of pinhole.

• Journal of the Korean Graphic Arts Communication Society
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• v.8 no.1
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• pp.71-87
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• 1990

This paper presents a simple algorithm to obtain three dimensional information of an object. In the preprocessing of the stereo matching,feature point informations of stero image must be less sensitive to noise and well liked the correspondance problem. This paper described a simple technique of struture feature extraction of 3-D object and used edge-end point expanding method for unconnected line instade of Hough transform. The feature such as corner point and their angles are used for matching problem. The experimental results show that the described algorithm is a useful method for stereo correspondence problem.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.2
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• pp.837-856
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• 2016

Underwater image enhancement has received considerable attention in last decades, due to the nature of poor visibility and low contrast of underwater images. In this paper, we propose a new automatic underwater image enhancement algorithm, which combines nonsubsampled contourlet transform (NSCT) domain enhancement techniques with the mechanism of the human visual system (HVS). We apply the multiscale retinex algorithm based on the HVS into NSCT domain in order to eliminate the non-uniform illumination, and adopt the threshold denoising technique to suppress underwater noise. Our proposed algorithm incorporates the luminance masking and contrast masking characteristics of the HVS into NSCT domain to yield the new HVS-based NSCT. Moreover, we define two nonlinear mapping functions. The first one is used to manipulate the HVS-based NSCT contrast coefficients to enhance the edges. The second one is a gain function which modifies the lowpass subband coefficients to adjust the global dynamic range. As a result, our algorithm can achieve contrast enhancement, image denoising and edge sharpening automatically and simultaneously. Experimental results illustrate that our proposed algorithm has better enhancement performance than state-of-the-art algorithms both in subjective evaluation and quantitative assessment. In addition, our algorithm can automatically achieve underwater image enhancement without any parameter tuning.