• Title/Summary/Keyword: central feature

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CFD based simulations of flutter characteristics of ideal thin plates with and without central slot

  • Zhu, Zhi-Wen;Chen, Zheng-Qing;Gu, Ming
    • Wind and Structures
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    • v.12 no.1
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    • pp.1-19
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    • 2009
  • In this paper, the airflow around an ideal thin plate (hereafter referred to as ITP) with various ratios of central slot is simulated by using the finite-difference-method (FDM)-based Arbitrary-Lagrangian-Eulerian descriptions for the rigid oscillating body. The numerical procedure employs the second-order projection scheme to decouple the governing equations, and the multigrid algorithm with three levels to improve the computational efficiency in evaluating of the pressure equation. The present CFD method is validated through comparing the computed flutter derivatives of the ITP without slot to Theodorsen analytical solutions. Then, the unsteady aerodynamics of the ITP with and without central slot is investigated. It is found that even a smaller ratio of central slot of the ITP has notable effects on pressure distributions of the downstream section, and the pressure distributions on the downstream section will further be significantly affected by the slot ratio and the reduced wind speeds. Continuous increase of $A_2^*$ with the increase of central slot may be the key feature of the slotted ITP. Finally, flutter analyses based on the flutter derivatives of the slotted ITP are performed, and moreover, flutter instabilities of a scaled sectional model of a twin-deck bridge with various ratios of deck slot are investigated. The results confirm that the central slot is effective to improve bridge flutter stabilities, and that the flutter critical wind speeds increase with the increase of slot ratio.

Immunocytochemical Mapping of Serotonergic Neurons in Postembrvonic Brains of Cabbage Butterfly Pieris rcpce (배추흰나비 유충, 용, 성충의 뇌에 분포하는 세로토닌 면역반응성 신경원)

  • 이봉희;심재원
    • The Korean Journal of Zoology
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    • v.35 no.4
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    • pp.428-438
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    • 1992
  • The serotonin-immunoreactive (5-HTil neurons have been investigated in the brains of lanra, pupa and adult from Pieris ropae. There are ca. 54 5-HTi neurons in 5-instar larva, ca. 20 in 2-dav-old pupa and ca. 118 in 1-day-old adult, respectively. Most of these 5-HTi neurons are interneurons, but efferent and afferent 5-HTi neurons were also observed. Most of the 5-HTi neurons project into the central neuropils of postembrvonic brains. The larval brain contains abundant 5-HTi processes in the central neuropils, including those in three cerebral commissures. But in the pupal brain the 5-HTi processes are restricted in small numbers to the given regions of central neuropil. The adult brain contains a large number of 5-HTi processes in mushroom body, central body complex, lateral protocerebrum, protocerebral bridge, antennal lobe, and tritocerebral and suboesophageal neuropils. However, the 5-HTi processes are not found in the optic lobe of the brains. One prominent feature of the 5-HTi fibers in the postembrvonic brains is the fact that they are greatly arborized.

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An improved collapse analysis mechanism for the face stability of shield tunnel in layered soils

  • Chen, Guang-hui;Zou, Jin-feng;Qian, Ze-hang
    • Geomechanics and Engineering
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    • v.17 no.1
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    • pp.97-107
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    • 2019
  • Based on the results of Han et al. (2016), in the failure zone ahead of the tunnel face it can be obviously identified that a shear failure band occurs in the lower part and a pressure arch happens at the upper part, which was often neglected in analyzing the face stability of shield tunnel. In order to better describe the collapse failure feature of the tunnel face, a new improved failure mechanism is proposed to evaluate the face stability of shield tunnel excavated in layered soils in the framework of limit analysis by using spatial discretization technique and linear interpolation method in this study. The developed failure mechanism is composed of two parts: i) the rotational failure mechanism denoting the shear failure band and ii) a uniformly distributed force denoting the pressure arch effect. Followed by the comparison between the results of critical face pressures provided by the developed model and those by the existing works, which indicates that the new developed failure mechanism provides comparatively reasonable results.

Epidemioclinical Feature of Early-Onset Colorectal Cancer at-Risk for Lynch Syndrome in Central Iran

  • Zeinalian, Mehrdad;Hashemzadeh-Chaleshtori, Morteza;Akbarpour, Mohammad Javad;Emami, Mohammad Hassan
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.11
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    • pp.4647-4652
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    • 2015
  • Background: Colorectal cancer (CRC) is becoming one of the most complicated challenges of human health, particularly in developing countries like Iran. In this paper, we try to characterize CRC cases diagnosed < age 50 at-risk for Lynch syndrome within central Iran. Materials and Methods: We designed a descriptive retrospective study to screen all registered CRC patients within 2000-2013 in Poursina Hakim Research Center (PHRC), a referral gastroenterology clinic in central Iran, based on being early-onset (age at diagnosis ${\leq}50years$) and Amsterdam II criteria. We calculated frequencies and percentages by SPSS 19 software to describe clinical and family history characteristics of patients with early-onset CRC. Results: Overall 1,659 CRC patients were included in our study of which 413 (24.9%) were ${\leq}50years$ at diagnosis. Of 219/413 successful calls 67 persons (30.6%) were reported deceased. Family history was positive for 72/219 probands (32.9%) and 53 families (24.2%) were identified as familial colorectal cancer (FCC), with a history of at-least three affected members with any type of cancer in the family, of which 85% fulfilled the Amsterdam II Criteria as hereditary non-polyposis colorectal cancer (HNPCC) families (45/219 or 20.5%). Finally, 14 families were excluded due to proband tumor tissues being unavailable or unwillingness for incorporation. The most common HNPCC-associated extracolonic-cancer among both males and females of the families was stomach, at respectively 31.8 and 32.7 percent. The most common tumor locations among the 31 probands were rectum (32.3%), sigmoid (29.0%), and ascending colon (12.9%). Conclusions: Given the high prevalence of FCC (~1/4 of early-onset Iranian CRC patients), it is necessary to establish a comprehensive cancer genetic counseling and systematic screening program for early detection and to improve cancer prognosis among high risk families.

Sex Differences in the memories for emotional stimuli (정서적 자극에 대한 기억에 있어서의 남녀 차이에 관한 연구)

  • 박수애;안진경
    • Science of Emotion and Sensibility
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    • v.6 no.3
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    • pp.29-43
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    • 2003
  • This study examined the difference in memories for emotional stimuli. After giving participants the memory task instruction that they should remember the given stimuli, the emotion-induced photographs and the neutral photographs were presented. To minimize the possibility to regulate the expressions of their mood which induced by emotional stimuli and to find out whether the antecedent-focused emotion regulation process would damaged the memory of emotional stimuli in men, participant's memory was measured directly after the presentation of each photograph by free reflection method. Also Sex differences in memories about emotional and neutral stimuli were measured and compared. Women memorized stimuli more than men, and as expected, women remembered more about the emotional stimuli than neutral ones. The analysis of sex difference about central and peripheral features indicated that women remembered central features of emotional stimulus more than those of neutral ones, but that men had no difference between central features of emotional stimuli and those of neutral ones. These results showed that men's damaged memories of emotional stimuli were caused by the antecedent-focused emotion regulation process.

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Face Recognition By Combining PCA and ICA (주 요소와 독립 요소 분석의 통합에 의한 얼굴 인식)

  • Yoo Jae-Hung;Kim Kang-Chul;Lim Chang-Gyoon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.4
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    • pp.687-692
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    • 2006
  • In a conventional ICA(Independent Component Analysis) based face recognition method, PCA(Principal Component Analysis) first is used for feature extraction, ICA learning method then is applied for feature enhancement in the reduced dimension. It is not considered that a necessary component can be located in the discarded feature space. In the new ICA(NICA), learning extracts features using the magnitude of kurtosis (4-th order central moment or cumulant). But, the pure ICA method can not discard noise effectively. The synergy effect of PCA and ICA can be achieved if PCA is used for noise reduction filter. Namely, PCA does whitening and noise filtering. ICA performs feature extraction. Experiment results show the effectiveness of the new ICA method compared to the conventional ICA approach.

An analytical solution to the mapping relationship between bridge structures vertical deformation and rail deformation of high-speed railway

  • Feng, Yulin;Jiang, Lizhong;Zhou, Wangbao;Lai, Zhipeng;Chai, Xilin
    • Steel and Composite Structures
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    • v.33 no.2
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    • pp.209-224
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    • 2019
  • This paper describes a study of the mapping relationship between the vertical deformation of bridge structures and rail deformation of high-speed railway, taking the interlayer interactions of the bridge subgrade CRTS II ballastless slab track system (HSRBST) into account. The differential equations and natural boundary conditions of the mapping relationship between the vertical deformation of bridge structures and rail deformation were deduced according to the principle of stationary potential energy. Then an analytical model for such relationship was proposed. Both the analytical method proposed in this paper and the finite element numerical method were used to calculate the rail deformations under three typical deformations of bridge structures and the evolution of rail geometry under these circumstances was analyzed. It was shown that numerical and analytical calculation results are well agreed with each other, demonstrating the effectiveness of the analytical model proposed in this paper. The mapping coefficient between bridge structure deformation and rail deformation showed a nonlinear increase with increasing amplitude of the bridge structure deformation. The rail deformation showed an obvious "following feature"; with the increase of bridge span and fastener stiffness, the curve of rail deformation became gentler, the track irregularity wavelength became longer, and the performance of the rail at following the bridge structure deformation was stronger.

Circumnuclear gas around the central AGN in a cool-core cluster, A1644-South

  • Baek, Junhyun;Chung, Aeree;Kim, Jae-Woo;Jung, Taehyun
    • The Bulletin of The Korean Astronomical Society
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    • v.45 no.1
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    • pp.30.2-31
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    • 2020
  • We present the properties of circumnuclear gas associated with the AGN located in the center of Abell 1644-South. A1644-S is the main cluster in a merging system, which is also known for gas sloshing in its core as seen in X-ray. The X-ray emission of A1644-S shows a rapidly declining profile, indicating the presence of cooling gas flow. This flow of cool gas may fuel the supermassive black hole embedded in the brightest cluster galaxy, leading to the activation of the central AGN. Indeed, we find a parsec-scale bipolar jet feature in the center of A1644-S in our recent KaVA observation, which implies that its central AGN is likely to have been (re)powered quite recently. In order to verify the hypothesis that cooling gas flow in the cluster core can (re)activate the central AGN, we probe the cold gas properties of the central 1 kpc region of A1644-S using the archival VLA and ALMA data. Based on the spatially resolved morphology and kinematics of HI and CO gas, we challenge to identify inflow/outflow gas streams and clumps. We study the role of circumnuclear cool gas in fueling the centrally located cluster AGN in the cool-core environment. We also discuss how the feedback due to the (re)powered AGN affects the surrounding medium.

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A Study on the Drift Effect of Instrument Channel for Nuclear Power Plant (원전 계측 채널 Drift에 관한 연구)

  • Kim, In Hwan;Kim, Hyeong Taek;Kim, Yun Jung
    • Journal of Energy Engineering
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    • v.23 no.3
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    • pp.96-101
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    • 2014
  • The Instrument Channel setpoints of the Reactor Protection System(RPS) and the Engineered Safety Feature Actuation System(ESFAS) ensures the safety of Nuclear Power Plants (NPPs), and the actuation of the protection system should be guaranteed on power change condition. The goal of this study is to verify the appropriateness of the sensor drift and rack drift which are important factors for setpoints evaluation and to improve the setpoints margin using the operation data, design specifications and operation manuals of the NPPS.

A Visualization System for Multiple Heterogeneous Network Security Data and Fusion Analysis

  • Zhang, Sheng;Shi, Ronghua;Zhao, Jue
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.6
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    • pp.2801-2816
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    • 2016
  • Owing to their low scalability, weak support on big data, insufficient data collaborative analysis and inadequate situational awareness, the traditional methods fail to meet the needs of the security data analysis. This paper proposes visualization methods to fuse the multi-source security data and grasp the network situation. Firstly, data sources are classified at their collection positions, with the objects of security data taken from three different layers. Secondly, the Heatmap is adopted to show host status; the Treemap is used to visualize Netflow logs; and the radial Node-link diagram is employed to express IPS logs. Finally, the Labeled Treemap is invented to make a fusion at data-level and the Time-series features are extracted to fuse data at feature-level. The comparative analyses with the prize-winning works prove this method enjoying substantial advantages for network analysts to facilitate data feature fusion, better understand network security situation with a unified, convenient and accurate mode.