• Title/Summary/Keyword: Level set methods

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A Saliency-Based Focusing Region Selection Method for Robust Auto-Focusing

  • Jeon, Jaehwan;Cho, Changhun;Paik, Joonki
    • IEIE Transactions on Smart Processing and Computing
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    • v.1 no.3
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    • pp.133-142
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    • 2012
  • This paper presents a salient region detection algorithm for auto-focusing based on the characteristics of a human's visual attention. To describe the saliency at the local, regional, and global levels, this paper proposes a set of novel features including multi-scale local contrast, variance, center-surround entropy, and closeness to the center. Those features are then prioritized to produce a saliency map. The major advantage of the proposed approach is twofold; i) robustness to changes in focus and ii) low computational complexity. The experimental results showed that the proposed method outperforms the existing low-level feature-based methods in the sense of both robustness and accuracy for auto-focusing.

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A SIMPLE APPROACH FOR ESTIMATING ANNUAL EVAPOTRANSPIRATION WITH CLIMATE DATA IN KOREA

  • Im Sangjun;Kim Hyeonjun;Kim Chulgyum;Jang Cheolhee
    • Water Engineering Research
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    • v.5 no.4
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    • pp.185-193
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    • 2004
  • Estimates of annual actual evapotranspiration are needed in water balance studies, water resources management projects, and many different types of hydrologic studies. This study validated a set of 5 empirical equations of estimating annual actual evapotranspiration with climate data on 11 watersheds, and evaluated the further applicability of these forms in estimating annual runoff on watershed level. Five empirical equations generally overestimated annual evapotranspiration, with relative errors ranging $3.3\%$ to $47.2\%$. The results show that Schreiber formula can be applicable in determining annual evapotranspiration in sub-humid region that is classified by aridity index, while Zhang equation gave better results than the remaining methods in humid region. The mean differences for annual evapotranspiration bias over 11 watersheds are Zhang, Schreiber, Budyko, Pike, and Ol'dekop formula from lowest to highest. The empirical equations provide a practical tool to help water resources managers in estimating regional water resources on ungauged large watershed.

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Software Taskset Processing Evaluation Based on a Mixed Debugging Process

  • Kim, U-Jung;Lee, Chong-Hyung
    • Communications for Statistical Applications and Methods
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    • v.19 no.4
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    • pp.571-577
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    • 2012
  • Modules that consist of software are respectively coded in the early development phase and the modules are unified as a software. After unification, the software is repeatedly tested with a given taskset (the set of module tasks that are tested simultaneously) until a required performance level is satisfied. In this paper, we expand the one-module software debugging model of Jang and Lee (2011) to a multi-module debugging model and derive the taskset completion probability and the mean of the completed tasksets under the assumption that the processing times of module tasks given in a taskset are mutually dependent.

Combination of isogeometric analysis and extended finite element in linear crack analysis

  • Shojaee, S.;Ghelichi, M.;Izadpanah, E.
    • Structural Engineering and Mechanics
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    • v.48 no.1
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    • pp.125-150
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    • 2013
  • This paper intends to present an application of isogeometric analysis in crack problems. An isogeometric formula is developed based on NURBS basis functions - enriched and adopted via X-FEM enrichment functions. The proposed method which is represented by the combination of the two above-mentioned methods, first by using NURBS functions models the geometry exactly and then by defining level set function on domain, identifies available discontinuity in elements. Additional DOFs are allocated to elements containing the crack and X-FEM enrichment functions enrich approximate solution. Moreover, a subelement refinement technique is used to improve the accuracy of integration by the Gauss quadrature rule. Finally, several numerical examples are illustrated to demonstrate the effectiveness, robustness and accuracy of the proposed method during calculation of crack parameters.

HMM-Based Transient Identification in Dynamic Process

  • Kwon, Kee-Choon
    • Transactions on Control, Automation and Systems Engineering
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    • v.2 no.1
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    • pp.40-46
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    • 2000
  • In this paper, a transient identification based on a Hidden Markov Model (HMM) has been suggested and evaluated experimentally for the classification of transients in the dynamic process. The transient can be identified by its unique time dependent patterns related to the principal variables. The HMM, a double stochastic process, can be applied to transient identification which is a spatial and temporal classification problem under a statistical pattern recognition framework. The HMM is created for each transient from a set of training data by the maximum-likelihood estimation method. The transient identification is determined by calculating which model has the highest probability for the given test data. Several experimental tests have been performed with normalization methods, clustering algorithms, and a number of states in HMM. Several experimental tests have been performed including superimposing random noise, adding systematic error, and untrained transients. The proposed real-time transient identification system has many advantages, however, there are still a lot of problems that should be solved to apply to a real dynamic process. Further efforts are being made to improve the system performance and robustness to demonstrate reliability and accuracy to the required level.

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The Effects of Task-Oriented Exercise Program on Balance Ability in Patients with Acute Stroke

  • Kang, Tae-Woo;Kim, Beom-Ryong
    • The Journal of Korean Physical Therapy
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    • v.30 no.4
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    • pp.112-116
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    • 2018
  • Purpose: This study aimed to identify the effects of a task-oriented exercise program on balance in patients with acute stroke. Methods: Twenty participants with hemiparesis resulting from acute stroke volunteered to participate in this study. They were randomly assigned to either the experimental or control group, with 10 patients per group. Both groups underwent a task-oriented exercise program averaging 30 minutes daily for 4 weeks. Balance was assessed before and after the 4-week training period. Before and after the intervention, we conducted a paired t-test to compare the within-group changes and an independent t-test to compare the between-group differences. The statistical significance level was set at p=0.05 for all the variables. Results: Both groups showed significant within-group and between-group changes in balance (p<0.05) after the intervention. Conclusion: This study provides valuable information for future studies in this field. Further research using a larger sample and longer experiment spans can corroborate the results of our study.

On the Evaluation of In-Vehicle Dynamic Characteristics and On-Road Dynamic Stability(Angle of Rotation) of Rearview Mirror (리어뷰 미러의 실차 동특성 및 주행시 동적 안정성(회전각)에 대한 평가)

  • Jung, Seung-Kyun;Lee, Keun-Soo;Kim, Jeung-Han
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.11a
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    • pp.385-386
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    • 2008
  • Dynamic stability of the vehicle rearview mirror is an important factor for the driver's visual perception (image blur) when driving down the road and regarded as one of the vehicle level N&V performance of visible component vibration. Several projects within GM identified a set of objective metrics and validation methods that can replace current existing subjective evaluation of mirror stability. This paper presents objective evaluation results for assessing dynamic stability (angle of rotation) of the vehicle rearview mirrors using both in-lab FRF measurements and on-road testing.

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Hormone-Mimic Chemicals and Their Possible Endocrine Disruption - Development of Testing Methods -

  • Imai, Kiyoshi
    • Toxicological Research
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    • v.17
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    • pp.313-317
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    • 2001
  • The Ministry of Health and Welfare of Japan has set up six research groups concerning the endocrine disrupting chemicals. One of these projects was "A study on development of testing methodology for health effects due to exposure of environmental endocrine disruptors". In this paper, three topics are described. In OECD collaboration for pre-validation of uterotrophic assay, the most sensitive response to ethnyl estradiol was noted in the ovarectomized rats treated subcutaneously for 7 days. Secondly, it was suggested that changes of the serum $\alpha_{2u}$-globulin level may be a sensitive parameter for detecting the estrogenic activities of chemicals. Finally, development of the sexually dimorphic nucleus of preoptic area in the brain oj male rats was inhibited by the treatment with estrogenic chemicals, and their masculine behaviors and reproductive abilities were impaired after sexual maturation. In conclusion, these parameters are considered to be sensitive endpoints for testing estrogenic chemicals.chemicals.

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A Study on the Underdrainage of Wet Paddy Fields by Using P.V.C. Pipes (PVC관을 이용한 배수연구)

  • 주재홍
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.12 no.2
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    • pp.1960-1964
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    • 1970
  • Underdrainage has been studied by using PVC suction pipes in the low and wet Paddy field: Fist, three test plot and three control plots were set and drainage methods and Soil tempratures in the test plots have been examined. The experiment was conducted making use of the 'NONG-RIM No, 4'(Wheat) 'DOWON' (rice barley), a recommended variety. Test period was from September, to December, 1969. The experimental methodsand results obtained through this experimontation are as follows: 1) Ground water level in the test plot goes down by 34 cm. 2) In sprouting, control plot is earlier than test plot by three days. 3) The rate of sprouting is equal.

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Numerical investigation of gaseous detonation observed in the elasto-plastic metal tubes (탄소성 금속관 내 가스 폭굉의 수치적 연구)

  • Gwak, Min-cheol;Do, Yeong-dea;Park, Jeong-su;Yoh, Jai-ick
    • 한국연소학회:학술대회논문집
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    • 2012.11a
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    • pp.85-87
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    • 2012
  • We present a numerical investigation on gaseous (ethylene-air mixture) detonation in the elastoplastical metal tubes to understand the wall effects associated with the developing detonation instability. The acoustic disturbances originating from the rapidly expanding tube walls reach the detonating flame surface, thereby causing flame distortions and total energy losses. The compressible Navier-Stokes equations with equation of state for gas and elasto-plastic deformation field equations for inert tubes are solved simultaneously to understand the complex multi-material interaction in the rapidly expanding gas pipe. In order to track governing variables across the material interface, we use the hybrid particle level-set and ghost fluid methods to precisely estimate the interfacial quantities. Features observed from the deforming (thin) tube show substantially different behavior when a detonation propagates in the rigid (thick) tube with no acoustically responding wall conditions.

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