• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2778-2791
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• 2017

In the age of big data, distributed data providers need to ensure the privacy, while data analysts need to mine the value of data. Therefore, how to find the privacy-utility tradeoff has become a research hotspot. Besides, the adversary may have the background knowledge of the data source. Therefore, it is significant to solve the privacy-utility tradeoff problem in the distributed environment with side information. This paper proposes a distributed privacy-utility tradeoff method using distributed lossy source coding with side information, and quantitatively gives the privacy-utility tradeoff region and Rate-Distortion-Leakage region. Four results are shown in the simulation analysis. The first result is that both the source rate and the privacy leakage decrease with the increase of source distortion. The second result is that the finer relevance between the public data and private data of source, the finer perturbation of source needed to get the same privacy protection. The third result is that the greater the variance of the data source, the slighter distortion is chosen to ensure more data utility. The fourth result is that under the same privacy restriction, the slighter the variance of the side information, the less distortion of data source is chosen to ensure more data utility. Finally, the provided method is compared with current ones from five aspects to show the advantage of our method.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.543-546
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• 2004

The inverse Compton scattering of the cosmic microwave background (CMB) radiation with electrons in the intracluster medium which has a temperature gradient, was examined by the third-order perturbation theory of the Compton scattering. A new type of the spectrum distortion of the CMB was found and named as gradient T Sunyaev-Zel'dovich effect (gradT SZE). The spectrum has an universal shape. There is a zero distortion point, the cross over frequency, at 326GHz. When the hotter region locates closer to an observer, the intensity becomes brighter than the CMB in the frequency region lower than the cross over frequency and fainter than the CMB in the frequency region higher than the cross over frequency. When the cooler region locates closer to an observer, the distorted part of the spectrum has an opposite sign to the above case. The amplitude of the spectrum distortion does not de-pend on the electron density and depends on the heat conductivity and the total temperature variation along a line of sight. Therefore, the gradT SZE provides an unique opportunity to measure thermally nonequilibrium electron momentum distribution function in the ICM and combined with the X-ray measurements of the electron temperature distribution provides an opportunity of direct measurement of the heat conductivity in the ICM.

• Journal of Broadcast Engineering
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• v.25 no.6
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• pp.882-897
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• 2020

Recently, the use of immersive media contents representing Panorama and 360° video is increasing. Since the viewing angle is limited to generate the content through a general camera, image stitching is mainly used to combine images taken with multiple cameras into one image having a wide field of view. However, if the parallax between the cameras is large, parallax distortion may occur in the stitched image, which disturbs the user's content immersion, thus an image stitching overcoming parallax distortion is required. The existing Seam Optimization based image stitching method to overcome parallax distortion uses energy function or object segment information to reflect the location information of objects, but the initial seam generation location, background information, performance of the object detector, and placement of objects may limit application. Therefore, in this paper, we propose an image stitching method that can overcome the limitations of the existing method by adding a weight value set differently according to the type of object to the energy value using object detection based on deep learning.

• Journal of Korea Multimedia Society
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• v.11 no.2
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• pp.206-213
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• 2008

Animation are consist of consecutive various images, and there are figure and ground. The value of figure image as character in animation consider more significant than the background image, it can be detected many literature reviews on that subject. It, however, is also a critical element for completing animation, in reality, it is not found many academical achievements on this subject. The background images imply the information of environment and atmosphere, and elucidates where the story happen, therefore character move, talk and express themselves there. In terms of academic endeavour to extend the knowledge on animation, this paper is one of vital researches to be suggest on background image study. The main purpose of this study is to classify the background images in the ways of three categories such as painting concepts of concrete, semi-abstract, and abstract to camera concept of deep-focus, out-focus, and distortion. It is to instigate for the study of background images, in the practical view. And it will be utilizing the basic theories of cognitive psychology, painting and camera techniques, in the ways of It is analysed to frequency of use, reality, amount of information, perspective, and role of background image. This study is to provide a basic theory of visual classification on background image for practicing animations and researching on this subject.

• Fashion & Textile Research Journal
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• v.15 no.6
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• pp.874-885
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• 2013

This study analyzes the visage in fashion illustration based on the deconstructed visage of Francis Bacon's paintings as well as analyzes fashion illustration works since 2000. The deconstructed visages in Francis Bacon's paintings are classified as blurring, elimination, distortion and division. The expressive methods and meanings in fashion illustration (according to categorization) are as follow. Blurring shows an ambiguous visage organ by the sweeping of the brush, removal of a boundary among the visage, body and clothes, gradation of organic line like visage shapes, stretching of the a plat combined to visage and fragmentation of visage. It represents an uncertainty of the fashion theme and image interpretation, impossibility of figure by ambiguity, fantastic effect and the induction of the uncanny. Elimination shows the background color's painting of a photo-montage, overlap of a cutting of visage's part and background of a plat, elimination of the visage and the elimination of eyes, nose or lips. It represents a weakened identity, the reinforcement of anonymity, creation of a violent image, and uncanny unfamiliarity. Distortion shows a distorted visage by free drawing, and unconscious drawing line, fluid digital body, combination of an unconscious curve, and an eccentric combination of the accidental. It represents the relief of specialty about realistic existence, hypothetical immateriality and fantasy. Division shows overlapped visages with different angles, the weird combination of a plural visage and different species and a plural breakaway of direction, and the position of several organs. It represents motion by power's trace, non-territory of species, ambiguity and uncertainty and the uncanny.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.191-195
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• 2005

We used Subaru observations of A1689 (z = 0.183) to derive an accurate, model-independent mass profile for the entire cluster, r$\le$2Mpc/h, by combining magnification bias and distortion measurements. The projected mass profile steepens quickly with increasing radius, falling away to zero at r${\~}$1.0Mpc/h, well short of the anticipated virial radius. Our profile accurately matches onto the inner profile, r $\le$200kpc/ h, derived from deep HST / ACS images. The combined ACS and Subaru information is well fitted by an NFW profile with virial mass, $(1.93 \pm 0.20) {\times}10^{15} M_{\bigodot}$, and surprisingly high concentration, $C_{vir} = 13.7^{+1.4}_{-1.1}$, significantly larger than theoretically expected ($C_{vir} {\le}4$), corresponding to a relatively steep overall profile. These results are based on a reliable sample of background galaxies selected to be redder than the cluster E/SO sequence. By including the faint blue galaxy population a much smaller distortion signal is found, demonstrating that blue cluster members significantly dilute the true signal for r $\le$ 400kpc/ h. This contamination is likely to affect most weak lensing results to date.

• Progress in Medical Physics
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• v.2 no.2
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• pp.183-192
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• 1991

Ophthalmoscopy following the intravenous injection of fluorescein has gained great diagnostic importance in ophthalmology. This technique provides sequential evaluation of the anatomic and physiologic status of the choroidal and retinal vasculature. In order to detect the changes between fluorescein ocular fundus image frames, the direct subtraction of the two frames is inadequate because of geometric distortions and background gray level differences in two images. In this study, a scheme for the correction of the geometric distortions is proposed. Precise control point coordinate values for transformation functions are manually determined after the process including a series of blood vessel detection and thinning, and one frame is mapped to another, and then a geometric distortion corrected image is obtained. When the corrected image is used in interframe change detections, a sucessful result is ensured.

• Journal of the Ergonomics Society of Korea
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• v.28 no.4
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• pp.91-99
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• 2009

A visual stress may provoke migraine, cephalalgia, intervene a long term reading and learning capability and reduce the productivity of a laborer who uses computer for a good while. In this study, a web based screening tool for visual stress was developed, it applied to 72 visually normal young persons in parallel with traditional questionnaire about symptoms of visual stress. To estimate visual stress, It is proposed to measure difference of visual search time of Han Gul characters as targets between visual stressful pattern and non-visual stressful pattern as global background of characters. As a result of test, 5 subjects were screened whose mean visual search time in the stressful pattern with 6 CPD spatial frequency increase significantly more than in none stressful pattern(t-test, one-tailed, p=$1.0407\times10^{-11}$). 2 of them were diagnosed as mild visual stress syndrome in the clinic. None had visual distortion and 50% of subjects had visual discomfort in results of the questionnaire. Correlation between visual search time increase rate and normalized number of visual discomfort may be slight(C. coefficient=0.1355). This study may contribute as a basic research for screening person with migraine, visual reading disabilities and VDT syndrome. It is required to apply the test to visual reading disabilities, migraine with visual distortion and/or visual discomfort as well as normal person for higher reliability of the screening tool.

• Journal of Power Electronics
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• v.16 no.1
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• pp.297-309
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• 2016

Grid-connected inverters (GCIs) with an LCL output filter have the ability of attenuating high-frequency (HF) switching ripples. However, by using only grid-current control, the system is prone to resonances if it is not properly damped, and the current distortion is amplified significantly under highly distorted grid conditions. This paper proposes a synchronous reference frame equivalent proportional-integral (SRF-EPI) controller in the αβ stationary frame using the parallel virtual resistance-based active damping (PVR-AD) strategy for grid-interfaced distributed generation (DG) systems to suppress LCL resonance. Although both a proportional-resonant (PR) controller in the αβ stationary frame and a PI controller in the dq synchronous frame achieve zero steady-state error, the amplitude- and phase-frequency characteristics differ greatly from each other except for the reference tracking at the fundamental frequency. Therefore, an accurate SRF-EPI controller in the αβ stationary frame is established to achieve precise tracking accuracy. Moreover, the robustness, the harmonic rejection capability, and the influence of the control delay are investigated by the Nyquist stability criterion when the PVR-based AD method is adopted. Furthermore, grid voltage feed-forward and multiple PR controllers are integrated into the current loop to mitigate the current distortion introduced by the grid background distortion. In addition, the parameters design guidelines are presented to show the effectiveness of the proposed strategy. Finally, simulation and experimental results are provided to validate the feasibility of the proposed control approach.

• Journal of the Korean Society of Radiology
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• v.10 no.4
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• pp.247-253
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• 2016

Ultrasound devices diagnose many disease, which is widely used, can not be standardized quantitative evaluated in order to evaluate sonography image of quality. Therefore, in this papers, aims to get correct image in order to accurate diagnosis by figuring out the appropriate parameter based on each target by measuring distortion which results in the analyzation of the sensitivity of SNR and the histogram of signal by manipulating parameter of 8 mm target in ATS-539 multipurpose phantom. Equipment using Acuson sequoia 512, convex probe and utilizes multi-objective phantom. experiment method is that first you put the phantom on the flat and acquire 85 sheets of image, changing frequency(2,3,4 MHz, harmonic 3, 4, 4.5 MHz), Focus(2, 4, 6 unit), and Dynamic Range(58, 68, 78, 88, 98) for a 8 mm structure. through the Image J program. The sensitivity angle of 8mm target through Image J program is gauged by each separate target SNR and the distorted angle subtract and measure Histogram of background from Histogram of signal and take top 40% from the given result value above. According to parameter variation we found out proper parameter by acquiring SNR of sensitivity and distortion data for aspect of transition. The more this findings have Focus, the lower distortion value and at 4 MHz frequency this result have high SNR and low distortion value. Dynamic Range got an appropriate image on 88 and 98. It is considered on the basis of the experimental data, the probability of disease diagnosis will get higher.