• Title/Summary/Keyword: Structure and function

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A Continuous Sliding Surface Transformed VSS by Saturation Function for MIMO Uncertain Linear Plants (다입출력 불확실 선형 플랜트를 위한 포화함수에 의한 연속 슬라이딩 면 변환 가변구조시스템)

  • Lee, Jung-Hoon
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.7
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    • pp.127-134
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    • 2015
  • In this note, a continuous sliding surface transformed variable structure systems by the saturation function is presented for MIMO uncertain linear plants. A discontinuous sliding surface transformed VSS is proposed theoretically. The closed loop exponential stability together with the MIMO existence condition of the sliding mode on the predetermined sliding surface is investigated. For practical applications, a continuous approximation of the discontinuous VSS is made by means of the saturation function. The discontinuity of the control input as the inherent property of the VSS is much improved in view of the practical aspects. Through a design example and simulation studies, the usefulness of the proposed continuous transformed VSS controller is verified.

Higher order DC for block ciphers with 2-block structure (2-블록 구조 블록 암호에 대한 고차 차분 공격)

  • 박상우
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.9 no.3
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    • pp.27-38
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    • 1999
  • We study on the security for the block ciphers with 20block structure which have provable security against DC and LC on the view point of higher order DC, 2-block structures are classified three types according to the location of round function such as C(Center)-type R(Right)-type and L(Left)-type We prove that in the case of 4 rounds encryption function these three types provide the equal strength against higher order DC and that in the case of 5 or more rounds R-type is weaker than C-type and L-type.

Simple Graphs for Complex Prediction Functions

  • Huh, Myung-Hoe;Lee, Yong-Goo
    • Communications for Statistical Applications and Methods
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    • v.15 no.3
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    • pp.343-351
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    • 2008
  • By supervised learning with p predictors, we frequently obtain a prediction function of the form $y\;=\;f(x_1,...,x_p)$. When $p\;{\geq}\;3$, it is not easy to understand the inner structure of f, except for the case the function is formulated as additive. In this study, we propose to use p simple graphs for visual understanding of complex prediction functions produced by several supervised learning engines such as LOESS, neural networks, support vector machines and random forests.

Bacterial Community Structure and Function Shift in Rhizosphere Soil of Tobacco Plants Infected by Meloidogyne incognita

  • Wenjie, Tong;Junying, Li;Wenfeng, Cong;Cuiping, Zhang;Zhaoli, Xu;Xiaolong, Chen;Min, Yang;Jiani, Liu;Lei, Yu;Xiaopeng, Deng
    • The Plant Pathology Journal
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    • v.38 no.6
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    • pp.583-592
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    • 2022
  • Root-knot nematode disease is a widespread and catastrophic disease of tobacco. However, little is known about the relationship between rhizosphere bacterial community and root-knot nematode disease. This study used 16S rRNA gene sequencing and PICRUSt to assess bacterial community structure and function changes in rhizosphere soil from Meloidogyne incognita-infected tobacco plants. We studied the rhizosphere bacterial community structure of M. incognita-infected and uninfected tobacco plants through a paired comparison design in two regions of tobacco planting area, Yuxi and Jiuxiang of Yunnan Province, southwest China. According to the findings, M. incognita infection can alter the bacterial population in the soil. Uninfested soil has more operational taxonomic unit numbers and richness than infested soil. Principal Coordinate Analysis revealed clear separations between bacterial communities from infested and uninfested soil, indicating that different infection conditions resulted in significantly different bacterial community structures in soils. Firmicutes was prevalent in infested soil, but Chloroflexi and Acidobacteria were prevalent in uninfested soil. Sphingomonas, Streptomyces, and Bradyrhizobium were the dominant bacteria genera, and their abundance were higher in infested soil. By PICRUSt analysis, some metabolism-related functions and signal transduction functions of the rhizosphere bacterial community in the M. incognita infection-tobacco plants had a higher relative abundance than those uninfected. As a result, rhizosphere soils from tobacco plants infected with M. incognita showed considerable bacterial community structure and function alterations.

Reliability Analysis of Tripod Support Structure for Offshore Wind Turbine using Stress Concentration Factor (응력집중계수를 이용한 해상풍력터빈 트라이포드 지지구조물의 신뢰성해석)

  • Lee, Sang Geun;Kim, Dong Hyawn
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.28 no.2
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    • pp.92-100
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    • 2016
  • Reliability analysis of tripod support structure for offshore wind turbine was performed. Extreme distribution function of peak response due to wind and wave loads was estimated by applying peak over threshold(POT) method. Then, stress based limit state function was defined by using maximum stress of support structure which was obtained by multiplying beam stress and concentration factor. The reliability analysis result was compared when maximum stress was calculated from shell element. Reliability index was evaluated using first order reliability method(FORM).

Security Properties of Domain Extenders for Cryptographic Hash Functions

  • Andreeva, Elena;Mennink, Bart;Preneel, Bart
    • Journal of Information Processing Systems
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    • v.6 no.4
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    • pp.453-480
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    • 2010
  • Cryptographic hash functions reduce inputs of arbitrary or very large length to a short string of fixed length. All hash function designs start from a compression function with fixed length inputs. The compression function itself is designed from scratch, or derived from a block cipher or a permutation. The most common procedure to extend the domain of a compression function in order to obtain a hash function is a simple linear iteration; however, some variants use multiple iterations or a tree structure that allows for parallelism. This paper presents a survey of 17 extenders in the literature. It considers the natural question whether these preserve the security properties of the compression function, and more in particular collision resistance, second preimage resistance, preimage resistance and the pseudo-random oracle property.

Frequency Domain Analysis for Hydrodynamic Responses of Floating Structure using Desingularized Indirect Boundary Integral Equation Method (비특이화 간접경계적분방정식 방법을 이용한 부유식 구조물의 유체동역학적 거동에 대한 주파수영역 해석)

  • Oh, Seunghoon;Jung, Dongho;Cho, Seok-kyu;Nam, Bo-woo;Sung, Hong Gun
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.1
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    • pp.11-22
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    • 2019
  • In this paper, a Rankine source method is applied and validated to analyze the hydrodynamic response of a three-dimensional floating structure in the frequency domain. The boundary value problems for radiation and diffraction problem are solved by using a desingularized indirect boundary integral equation method (DIBIEM). The DIBIEM is simpler and faster than conventional methods based on the numerical surface integration of Green's function because the singularities of Green's function are located outside of fluid regions. In case of floating structure with complex geometry, it is difficult to desingularize the singularities of Green's function consistently. Therefore a mixed approach is carried out in this study. The mixed approach is partially desingularized except singularities of the body. Wave drift loads are calculated by the middle-field formulation method that is mathematically simple and has fast convergence. In order to validate the accuracy of the developed program, various numerical simulations are carried out and these results are analyzed and compared with previously published calculations and experiments.