• International Journal of Contents
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• v.11 no.2
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• pp.20-30
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• 2015

We propose a new method that specifies objective image quality factors by evaluating an image quality measurement model using random images. In other words, No-Reference variables are used to evaluate the quality of an original image without using any reference for comparison. 1000 portrait images were collected from a web gallery with votes constituting over 30 recommendation values. The bottom-up data collecting process was used to calculate the following image quality factors: total range, average, standard deviation, normalized distribution, z-score, preference percentage. A final grade is awarded out of 100 points, and this method ranks and grades the final estimated image quality preference in terms of total image quality factors. The results of the proposed image quality evaluation model consist of the specific dynamic range, skin tone R, G, B, L, A, B, and RSC contrast. We can present the total for the expected preference points as the average of the objective image qualities. Our proposed image quality evaluation model can measure the preferences for an actual image using a statistical analysis. The results indicate that this is a practical image quality measurement model that can extract a subject's preferred image quality.

• Journal of Integrative Natural Science
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• v.1 no.2
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• pp.79-83
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• 2008

As a new standard for performance measurement, NEMA NU2-2001 was presented recently. In this study, I investigated the spatial resolution, sensitivity, scatter fraction, and noise equivalent count ratio (NECR) in order to know the information of physical characteristics and system performance of GE discovery ST using this new standard. Bismuth germinate crystals ($6{\times}6$ array, $6.3mm{\times}6.3mm{\times}30mm$) were used in discovery ST (energy window:375-650 keV, coincidence window:11.7 nsec). To measure the sensitivity, five aluminum sleeves (Data Spectrum Corp., Chapel Hill, NC., USA, thickness:1.25 mm)-NEMA sensitivity phantom- filled with F-18 solution were used. Successive measurements in 2D and 3D acquisition mode were made with a line source at the center of transaxial field of view and 10 cm off from the center until the count was over 500,000. Spatial resolution was estimated using a point source (F-18, 0.1 mCi) at different locations in the FOV. Scatter fraction and NECR was tested using a NEMA scatter phantom. Dynamic data were acquired for 7 half-lives using F-18 solution. And true to background ratio was averaged at last three frames when the random rate was as small as ignorable for the calculation of scatter fraction. We anticipate this overall evaluated results could be used for the quality assurance and optimized image acquisition for clinical research.

• Journal of the Korean Data and Information Science Society
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• v.22 no.4
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• pp.717-726
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• 2011

The present study was carried out to summarize the effect of green tea in the diabetic rats by meta-analysis related studies. The association measure to test effect of green tea was Hedges' standardized mean difference. In this particular fixed effect model, body weight was significantly increased. Also, blood glucose, triglycerides were significantly decreased. In this case of heterogeneous variable, random effect model was applied. In this model, body weight was significantly increased. Also, blood glucose was significantly decreased in green tea treated group. According to the Meta-regression analysis, duration of injection was not significant for variables.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.10B
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• pp.1216-1221
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• 2011

We propose a multiplexed fiber Bragg grating (FBG) sensor network for vessel monitoring to measure the variation of strain and temperature by environmental perturbation based on code division multiple access (CDMA). The center wavelength of FBG was linearly changed by environmental perturbation such as strain and temperature variation so that we could be monitoring the state of sensors. A RSOA was used as optical broadband source and which was modulated by using pseudo random binary sequence (PRBS) signal. The correlation peak of reflected signal from sensor networks was measured. In this paper, we used the sliding correlation techniques for high speed response and dynamic rage of sensors.

• Journal of IKEEE
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• v.17 no.1
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• pp.29-35
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• 2013

In this paper, we suggest an improved Convex Hull algorithm considering sort in plane point set. This algorithm has low computational complexity since processing data are reduced by characteristic of extreme points. Also it obtains a complete convex set with just one processing using an convex vertex discrimination criterion. Initially it requires sorting of point set. However we can't quickly sort because of its heavy operations. This problem was solved by replacing value and index. We measure the execution time of algorithms by generating a random set of points. The results of the experiment show that it is about 2 times faster than the existing algorithm.

• Computers and Concrete
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• v.15 no.4
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• pp.485-501
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• 2015

Cooling by the flow of water through an embedded cooling pipe has become a common and effective artificial thermal control measure for massive concrete structures. However, an extreme thermal gradient induces significant thermal stress, resulting in thermal cracking. Using a mesoscopic finite-element (FE) mesh, three-phase composites of concrete namely aggregate, mortar matrix and interfacial transition zone (ITZ) are modeled. An equivalent probabilistic model is presented for failure study of concrete by assuming that the material properties conform to the Weibull distribution law. Meanwhile, the correlation coefficient introduced by the statistical method is incorporated into the Weibull distribution formula. Subsequently, a series of numerical analyses are used for investigating the influence of the correlation coefficient on tensile strength and the failure process of concrete based on the equivalent probabilistic model. Finally, as an engineering application, damage and failure behavior of concrete cracks induced by a water-cooling pipe are analyzed in-depth by the presented model. Results show that the random distribution of concrete mechanical parameters and the temperature gradient near water-cooling pipe have a significant influence on the pattern and failure progress of temperature-induced micro-cracking in concrete.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.11a
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• pp.142-145
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• 2014

동영상에서의 객체 추적 알고리즘에 대한 활발한 연구가 진행되고 있음에도 불구하고 실시간 객체추적을 위해서는 여전히 정확도, 복잡도 등에서의 성능향상이 필요하다. 압축영역 기반 방식에서는 전역 움직임 보상(GMC : Global Motion Compensation)과정을 거쳐 추적하려는 객체와 배경을 구분한다. 전역 움직임 보상방법은 프레임 전 영역을 대상으로 하는 연산으로 전체 추적 시스템에서 차지하는 복잡도가 높다. 본 논문은 관심영역(ROI : Region Of Interest) 기반 전역 움직임 보상방법을 이용한 ST-MRF(Spatio-Temporal Markov Random Field)기반 추적기 고속화 방법을 제안한다. 관심영역을 기반으로 전역 움직임 보상을 적용함으로써 객체와 배경을 분리할 뿐만 아니라 알고리즘의 복잡도를 효과적으로 줄일 수 있다. 제안하는 방법의 추적성능은 평균 precision 87.29%, recall 82.58%, F-measure 83.78%로 기존방법과 비교하여 약 1%의 차이를 유지하였으며 전체 시스템의 수행시간은 평균 29.95ms로 기존방법과 비교하여 1.74배의 속도향상을 보였다.

• Korean Journal of Remote Sensing
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• v.25 no.3
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• pp.295-309
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• 2009

In this study, an iterative maximum a posteriori (MAP) approach using a Bayesian model of Markovrandom field (MRF) was proposed for despeckling images that contains speckle. Image process is assumed to combine the random fields associated with the observed intensity process and the image texture process respectively. The objective measure for determining the optimal restoration of this "double compound stochastic" image process is based on Bayes' theorem, and the MAP estimation employs the Point-Jacobian iteration to obtain the optimal solution. In the proposed algorithm, MRF is used to quantify the spatial interaction probabilistically, that is, to provide a type of prior information on the image texture and the neighbor window of any size is defined for contextual information on a local region. However, the window of a certain size would result in using wrong information for the estimation from adjacent regions with different characteristics at the pixels close to or on boundary. To overcome this problem, the new method is designed to use less information from more distant neighbors as the pixel is closer to boundary. It can reduce the possibility to involve the pixel values of adjacent region with different characteristics. The proximity to boundary is estimated using a non-uniformity measurement based on standard deviation of local region. The new scheme has been extensively evaluated using simulation data, and the experimental results show a considerable improvement in despeckling the images that contain speckle.

• Journal of the Optical Society of Korea
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• v.16 no.4
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• pp.372-380
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• 2012

The optical method Digital Speckle Correlation Measurement (DSCM) has been extensively applied due its capability to measure the entire displacement field over a body surface. A formula of displacement measurement errors by the gradient-based DSCM method was derived. The errors were found to explicitly relate to the image grayscale errors consisting of sub-pixel interpolation algorithm errors, image noise, and subset deformation mismatch at each point of the subset. A power-law dependence of the standard deviation of displacement measurement errors on the subset size was established when the subset deformation was rigid body translation and random image noise was dominant and it was confirmed by both the numerical and experimental results. In a gradient-based algorithm the basic assumption is rigid body translation of the interrogated subsets, however, this is in contradiction to the real circumstances where strains exist. Numerical and experimental results also indicated that, subset shape function mismatch was dominant when the order of the assumed subset shape function was lower than that of the actual subset deformation field and the power-law dependence clearly broke down. The power-law relationship further leads to a simple criterion for choosing a suitable subset size, image quality, sub-pixel algorithm, and subset shape function for DSCM.

• Journal of Distribution Science
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• v.19 no.12
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• pp.57-69
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• 2021

Purpose: This study aims to measure whether the business performance of Padang restaurants in North Jakarta is primarily affected by service distribution strategy and other factors, specifically the local-based organizational culture and entrepreneurial orientation. Research design, data and methodology: This quantitative research has used Structural Model-Partial Least Square (PLS-SEM) with SMART PLS 3.0 as the analytical tool. The study's sample focus is the owner or person in charge of the Padang restaurant business in North Jakarta. Data has been collected using a questionnaire instrument with a Likert scale scale ('1-strongly disagree' to '5-strongly agree'). A total of 86 samples with a random technique were obtained from three areas in North Jakarta: Kelapa Gading, Pademangan, and Penjaringan. Results: Interestingly, this research finds that service distribution strategy does not affect business performance, either directly or indirectly. Business performance in this study is affected by entrepreneurial orientation. In additional results, the local organizational culture significantly affects the entrepreneurial orientation, but does not affect the business performance in terms of management process. Conclusions: This study provides practical implications for restaurant businesses regarding the use of local cultural concepts to consider strategies for survival in today's challenging times while continuing operations during limitations.