• Title/Summary/Keyword: Gradients

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Efficient Image Deblurring using Edge Prediction (에지 예측을 기반으로 한 효율적인 영상 디블러링 -선명한 에지 예측을 기반으로 한 장의 영상으로부터의 모션 블러 제거-)

  • Cho, Sung-Hyun;Lee, Seung-Yong
    • 한국HCI학회:학술대회논문집
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    • 2009.02a
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    • pp.27-33
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    • 2009
  • We propose an efficient method for single image motion deblurring using edge prediction. Previous methods for motion deblurring from a single image have been based on total variation or natural image statistics. In contrast, our method predicts sharp edges by applying bilateral and shock filters and manipulating image gradients directly, and estimates motion blur using the predicted sharp edges. Sharp edge prediction makes our method possible to deblur efficiently with less computation. Results show that our method can effectively and efficiently restore images degraded by large complex motion blur.

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Electrical Stimulation System Design for Pharyngeal Dysfunction of Stroke Patients (뇌졸중 환자의 인두기능 회복을 위한 전기자극기 설계)

  • 김성민;배하석
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.1232-1235
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    • 2004
  • The purpose of this study is to design electrical stimulation system for pharyngeal dysfunction(dysphagia) in stroke patients. Pharyngeal muscle group activity is important, because contracting muscles provide the driving force at the initiation of the swallow and generate the pressure gradients necessary for bolus movement into the esophagus. Although we have many treatment methods for dysphagia, electrical stimulation system will be useful for stroke patients having dysphagia. Electrical stimulation can be divided into the body stimulation and electrodes. The body stimulation is divided again into frequency counter, time control and current measurement part. These parts are to control the current intensity, frequency and stimulating time. And they can be variable according to the patient's clinical assessment. The electrode plays a role to deliver the current from the system to the muscle. Also the position of the electrode can be variable according to the treatment method. We performed the clinical experiment with the stroke patient who has swallowing disorder. The videofluoroscopy was used for the observation. From the result of clinical experiment based on electrical stimulation, we expected that the dysfunction(in pharynx) level of the patient can be improved. However we could not have enough effectiveness of the treatment because of the number of patients, patient's adaptation and treatment period. We will design the optimized electrical stimulation system based on enough clinical experiment in the future.

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Inhibititory Activity of Flavonoid Acetates on the Histamine Release from IgE-Sensitized Mast Cells

  • Shin, Wha-Woo;Kim, Chun-Re;Choi, Se-Woong;Kim, Sung-Jin;Cho, Seung-Kil;Kim, Chang-Jong
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1996.04a
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    • pp.255-255
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    • 1996
  • Flavonoids are the large class of plant-derived polyphenolic compounds with a broad spectrum of biological actions including anti-inflammatory, anti-allergic and anti-asthmatic activities. It has been reported that quercetin and some other flavonoids inhibit the histamine release from mast cells. Disodium cromoglycate, a kind of biflavonoid, have been used as a anti-asthmatic agent. Therefore, the following study was undertaken to characterize tile structure-activity relationships of flavonoids in the inhibition of histamine release, from IgE-sensitized mast cells. Flavonoid acetate were synthesized by addition of acetic anhydride to the flavonoids dissolved in pyridine. According In the Mota method, IgE-rich serum was made in rats sensitized with Pertussis vaccine and ovalbumin. Rat abdominal mast cells were harvested and purified over tile discontineous Percoll gradients, Mast cells were preincubated in RPMI with IgE-rich serum and further incubated with flavonoids. Histamine contents released from mast cells were determined fluorospectrophotometrically after stimulation with ovalbumin. (omitted)

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A Numerical Model for the Freeze-Thaw Damages in Concrete Structures

  • Cho Tae-Jun
    • Journal of the Korea Concrete Institute
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    • v.17 no.5 s.89
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    • pp.857-868
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    • 2005
  • This paper deals with the accumulated damage in concrete structures due to the cyclic freeze-thaw as an environmental load. The cyclic ice body nucleation and growth processes in porous systems are affected by the thermo-physical and mass transport properties, and gradients of temperature and chemical potentials. Furthermore, the diffusivity of deicing chemicals shows significantly higher value under cyclic freeze-thaw conditions. Consequently, the disintegration of concrete structures is aggravated at marine environments, higher altitudes, and northern areas. However, the properties of cyclic freeze-thaw with crack growth and diffusion of chloride ion effects are hard to be identified in tests, and there has been no analytic model for the combined degradations. The main objective is to determine the driving force and evaluate the reduced strength and stiffness by freeze-thaw. For the development of computational model of those coupled deterioration, micro-pore structure characterization, pore pressure based on the thermodynamic equilibrium, time and temperature dependent super-cooling with or without deicing salts, nonlinear-fracture constitutive relation for the evaluation of internal damage, and the effect of entrained air pores (EA) has been modeled numerically. As a result, the amount of ice volume with temperature dependent surface tensions, freezing pressure and resulting deformations, and cycle and temperature dependent pore volume has been calculated and compared with available test results. The developed computational program can be combined with DuCOM, which can calculate the early aged strength, heat of hydration, micro-pore volume, shrinkage, transportation of free water in concrete. Therefore, the developed model can be applied to evaluate those various practical degradation cases as well.

A Real-time Pedestrian Detection based on AGMM and HOG for Embedded Surveillance

  • Nguyen, Thanh Binh;Nguyen, Van Tuan;Chung, Sun-Tae
    • Journal of Korea Multimedia Society
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    • v.18 no.11
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    • pp.1289-1301
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    • 2015
  • Pedestrian detection (PD) is an essential task in various applications and sliding window-based methods utilizing HOG (Histogram of Oriented Gradients) or HOG-like descriptors have been shown to be very effective for accurate PD. However, due to exhaustive search across images, PD methods based on sliding window usually require heavy computational time. In this paper, we propose a real-time PD method for embedded visual surveillance with fixed backgrounds. The proposed PD method employs HOG descriptors as many PD methods does, but utilizes selective search so that it can save processing time significantly. The proposed selective search is guided by restricting searching to candidate regions extracted from Adaptive Gaussian Mixture Model (AGMM)-based background subtraction technique. Moreover, approximate computation of HOG descriptor and implementation in fixed-point arithmetic mode contributes to reduction of processing time further. Possible accuracy degradation due to approximate computation is compensated by applying an appropriate one among three offline trained SVM classifiers according to sizes of candidate regions. The experimental results show that the proposed PD method significantly improves processing speed without noticeable accuracy degradation compared to the original HOG-based PD and HOG with cascade SVM so that it is a suitable real-time PD implementation for embedded surveillance systems.

Study on the Simulation of the 4-Stroke Cycle Spark Ignition Engines (First Paper) (4 행정 사이클 스파크 점화기관의 시뮬레이션에 관한 연구 (제1보))

  • 윤건식;우석근;서문진;신승한
    • Journal of Advanced Marine Engineering and Technology
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    • v.25 no.6
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    • pp.1260-1271
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    • 2001
  • The simulation program which predicts the gas behavior in a spark ignition engine has been developed and verified by the comparison with the experimental results foy the MPI engine, naturally aspirated and turbochared engines with a carburettor. First paper describes the calculations of the behavior of gas in the intake and exhaust system. The generalized method of characteristics including friction, heat transfer, area change and entropy gradients was used to analyse the pipe flow The constant-Pressure model was applied for the analysis of the flow through engine valved, and the constant-pressure perfect-mixing model was applied for the flow at manifold junction. The concept of the sudden area change was used for the muffler and catalytic convertor. Fer the plenum chamber in an MPI engine, constant-pressure model and constant-volume model were both examined. Through the comparison of predicted results with experiments, the simulation program was verified by showing good prediction of the behavior of IC engine qualitatively and quantitatively under wide range of operating conditions.

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Temporal and spatial variation in the distribution of life history phases of Chondrus crispus (Gigartinales, Rhodophyta)

  • Garbary, David J.;Tompkins, Elizabeth;White, Katelyn;Corey, Peter;Kim, Jang-K.
    • ALGAE
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    • v.26 no.1
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    • pp.61-71
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    • 2011
  • Thirty populations of Chondrus crispus Stackhouse from Nova Scotia were collected during the years 1993 to 2011. Taken from estuaries, wave exposed open coasts, high intertidal rock pools and shallow subtidal habitats, the populations were evaluated for relative abundance of tetrasporophytic and gametophytic life history phases. Over 2,800 thalli were characterized using the resorcinol-acetal test to distinguish the kappa- and lambda-carrageenan containing fronds of gametophytes and tetrasporophytes, respectively. These populations had $77{\pm}5%$ gametophytes (mean ${\pm}95%$ confidence interval), with most populations having gametophyte : sporophyte ratios ranging from 2 : 1 to 9 : 1. No population had a dominance of tetrasporophytes, although two populations had 1 : 1 ratios. A meta-analysis of our data along with previously published accounts showed no significant changes in gametophyte dominance with respect to hypothesized gradients of wave exposure, salinity, or water depth. Significant changes occurred in ratios at five sites where replicate sampling occurred in different years. We conclude that C. crispus in Maritime Canada has a natural ratio of 3 : 1 or greater in stable conditions, and that lower ratios represent recovery from disturbance in which bare substratum is created that is subsequently colonized by carpospores from remaining gametophytic thalli.

A Hydrodynamic Solution for the Lateral Spreading of a River Plume (하천수 플룸 횡방향 퍼짐의 해석해)

  • Yu, Hong-Sun;Lee, Jun
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.5 no.4
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    • pp.302-306
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    • 1993
  • Assuming Gaussian distribution of the density difference between a turbulent jet river plume and its ambient saline water, a hydrodynamic solution for the lateral spreading of a river plume is developed. Two advantages can be expected from the assumption we made. Firstly, we need not consider mixing processes in the plume in dealing with this Problem. Secondly, by Putting pressure gradients which can be obtained from the density distribution, into the equation of motion, we can solve them easily. We compared the analytic solution with the fold data of the Nakdong river plume and found reasonably good correspondence.

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Normal and Micro Gravity Experiments on Propagation Speed of Tribrachial Flame of Propane in Laminar Jets (정상 및 미소중력장에서 프로판 층류 제트 삼지 화염의 전파속도에 관한 실험적 연구)

  • Lee, J.;Won, S.H.;Jin, S.H.;Fujita, O.;Ito, K.;Chung, S.H.
    • Journal of the Korean Society of Combustion
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    • v.7 no.3
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    • pp.47-54
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    • 2002
  • The propagation speed of tribrachial flame in laminar propane jets has been investigated experimentally under normal and micro gravity conditions. The displacement speed was found to vary nonlinearly with axial distance because flow velocity along stoichiometric contour was comparable to the propagation speed of tribrachial flame for the present experiment. Approximate solutions for velocity and concentration accounting density difference and virtual origins have been used in determining the propagation speeds of tribrachial flame. Under micro gravity condition, the results showed that propagation speed of tribrachial flame is largely affected by the mixture fraction gradients, in agreement with previous studies. The limiting maximum value. of propagation speeds under micro gravity conditions are in good agreement with the theoretical prediction, that is, the ratio of maximum propagation speed to the stoichiometric laminar burning velocity is proportional to the square root of the density ratio of unburned to burnt mixture.

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Evidence for Sulfite Proton Symport in Saccharomyces cerevisiae

  • Park, Hoon;Alan T. Bakalinsky
    • Journal of Microbiology and Biotechnology
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    • v.14 no.5
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    • pp.967-971
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    • 2004
  • The kinetics of sulfite uptake were examined in a wild-type laboratory strain of Saccharomyces cerevisiae to determine if carrier-mediated sulfite uptake involved a proton symport, as previous studies on sulfite uptake have suggested both an active process and facilitated diffusion. Accumulation of intracellular sulfite was initially rapid and linear up to 50 sec. Uptake was saturable at final concentrations equal to or greater than 3 mM sulfite, and increased 2-fold in the presence of 2% glucose. Uptake was significantly reduced in cells pretreated with 100-500 $\mu$M carbonyl cyanide mchlorophenylhydrazone (CCCP) or 2,4-dinitrophenol (DNP), both of which dissipate proton gradients. Uptake was also significantly inhibited in the presence of 1 mM arsenate, an inhibitor of ATP synthesis. Extracellular alkalization was observed in cells incubated with 1-2 mM sulfite in a weak tartrate buffer at pH 3.5 and 4.5. These findings suggest that the bisulfite ion, $HSO_3^-$, an anionic form of sulfite, is taken up by a carrier-mediated proton symport. A met16 sull sul2 mutant, impaired in both sulfite formation and sulfate uptake, was found able to grow on a medium with sulfite as the sole Sulfur source, indicating that the sulfate transporters Sul1p and Sul2p are not required for sulfite uptake.