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Local Influence Assessment of the Misclassification Probability in Multiple Discriminant Analysis

  • Jung, Kang-Mo
    • Journal of the Korean Statistical Society
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    • v.27 no.4
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    • pp.471-483
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    • 1998
  • The influence of observations on the misclassification probability in multiple discriminant analysis under the equal covariance assumption is investigated by the local influence method. Under an appropriate perturbation we can get information about influential observations and outliers by studying the curvatures and the associated direction vectors of the perturbation-formed surface of the misclassification probability. We show that the influence function method gives essentially the same information as the direction vector of the maximum slope. An illustrative example is given for the effectiveness of the local influence method.

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Effects of Carbonation on the Microstructure of Cement Materials: Influence of Measuring Methods and of Types of Cement

  • Pham, Son Tung;Prince, William
    • International Journal of Concrete Structures and Materials
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    • v.8 no.4
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    • pp.327-333
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    • 2014
  • The objective of this work was to examine the influence of carbonation on the microstructure of cement materials. Different materials, which were CEM I mortar and paste, CEM II mortar and paste, were carbonated at $20^{\circ}C$, 65 % relative humidity and 20 % of $CO_2$ concentration. The specific surface area and pore size distribution were determined from two methods: nitrogen adsorption and water adsorption. The results showed that: (1) nitrogen adsorption and water adsorption do not cover the same porous domains and thus, we observed conflicts in the results obtained by these two techniques; (2) the CEM II based materials seemed to be more sensible to a creation of mesoporosity after carbonation than the CEM I based materials. The results of this study also helped to explain why observations in the literature diverge greatly on the influence of carbonation on specific surface area.

Stress Intensity Factor Calculation for the Semi-elliptical Surface Flaws on the Thin-Wall Cylinder using Influence Coefficients (영향계수를 이용한 원통용기 표면결함의 응력확대계수의 계산)

  • Jang, Chang-Heui;Moonn, Ho-Rim;Jeong, Ill-Seok
    • Proceedings of the KSME Conference
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    • 2001.06a
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    • pp.280-285
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    • 2001
  • As an integral part of the probabilistic fracture mechanics analysis, stress intensity factor calculation scheme for semi-elliptical surface flaws in thin-walled cylinder has been introduced. The approximation solution utilizes the influence coefficients to calculate the stress intensity factor at the crack tip. This method has been compared with other solution methods including 3-D finite element analysis for cooldown boundary condition. The analysis results confirmed that the simplified methods provided sufficiently accurate stress intensity factor values for axial semi-elliptcal flaws on the surface of the reactor pressure vessel.

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On the influence of polymer surface layer thickness on the adhesion of composite assembly. Differences between initial state and thermal ageing.

  • Benard, Q.;Fois, M.;Picard, C.;Grisel, M.
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.363-363
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    • 2006
  • Bonding of composite materials with an adhesive layer is one of the most promising alternatives to classical bonding techniques. The use of several surface treatments may greatly increase this adhesion behavior at the initial state. Then in order to see the influence of the thickness of polymer matrix on the adhesion of composite assembly, different surface treatment, which can reduce or increase this thickness, are used (peel ply, tear ply, excimer laser). The influence of this specific parameter is not only discussed at the initial state but also after thermal ageing of the whole bonded assembly. Results show that the best performances at the initial state are not obviously the best performances after ageing.

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Surface elasticity and residual stress effect on the elastic field of a nanoscale elastic layer

  • Intarit, P.;Senjuntichai, T.;Rungamornrat, J.;Rajapakse, R.K.N.D.
    • Interaction and multiscale mechanics
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    • v.4 no.2
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    • pp.85-105
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    • 2011
  • The influence of surface elasticity and surface residual stress on the elastic field of an isotropic nanoscale elastic layer of finite thickness bonded to a rigid material base is considered by employing the Gurtin-Murdoch continuum theory of elastic material surfaces. The fundamental solutions corresponding to buried vertical and horizontal line loads are obtained by using Fourier integral transform techniques. Selected numerical results are presented for the cases of a finite elastic layer and a semi-infinite elastic medium to portray the influence of surface elasticity and residual surface stress on the bulk stress field. It is found that the bulk stress field depends significantly on both surface elastic constants and residual surface stress. The consideration of out-of-plane terms of the surface stress yields significantly different solutions compared to previous studies. The solutions presented in this study can be used to examine a variety of practical problems involving nanoscale/soft material systems and to develop boundary integral equations methods for such systems.

Surface Characteristics and Tracking Resistance of Epoxy Insulating Materials against Ultraviolet (자외선 열화에 의한 에폭시 절연재료의 표면특성과 내트래킹성)

  • Cho, Han-Goo;Yoo, Dae-Hoon;Kang, Hyung-Kyung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.495-496
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    • 2008
  • This paper describes the influence of Ultra-violet irradiation on time to tracking resistance of epoxy insulating materials by use of the inclined plane test. And, the influence of surface degradation was evaluated through several method such as measurement of contact angle, surface roughness, using a scanning electron microscopy. As the 1000 hours of the surface degradation with UV-CON, the flashover time decreases at different rates depending on epoxy resin and silicone rubber specimen. As the duration of the surface degradation with UV-CON is prolonged, the contact angle of epoxy resin decreases at the rate of degradation time, while that of silicone rubber was not exchanged. It is assumed that this phenomenon is related to the decrease in hydrophobicity of the surface of the materials. Also, as to epoxy resin, the decrease of hydrophobicity due to surface degradation with UV-CON is greater than that resulting from surface degradation with WOM. The UV radiation produced chalking and crazing on the surface of the insulating materials specimen.

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Micro-EHL Analysis of a Ball Joint Contact with Surface Roughness (표면 거칠기를 고려한 볼 조인트 접촉의 미세 탄성유체윤활 해석)

  • 김태종
    • Tribology and Lubricants
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    • v.19 no.3
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    • pp.123-132
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    • 2003
  • The effect of surface texture on elastohydrodynamic lubrication (EHL) point contact of a ball Joint mechanism in small reciprocating compressors is studied numerically by using multigrid method. Pressure and film thickness profiles have been calculated for surface roughness with waviness of different orientations and transverse ridge and dent at minimum and maximum Hoes M parameter conditions. The influence of the amplitude and the wavelength of the surface roughness was also studied. Results show that the oblique waviness with orientation angle of 30$^{\circ}$generates the smallest minimum film thickness as compared with those of longitudinal, transverse, and other oblique roughness. The influence of transverse waviness on the minimum film thickness is smaller than for the longitudinal waviness case.

Influence on a density of micro-scale dimple for surface texturing on friction control (마찰제어를 위한 Surface texturing의 Micro-scale dimple 밀도영향)

  • Chae, Young-Hun;Kim, Seock-Sam
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.945-950
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    • 2004
  • Surface texturing of tribological application is another attractive technology of friction reducing. Also, reduction of friction is therefore considered to be a necessary requirement for improved efficiency of machine. In this paper attempts to investigate the effect of density for micro-scale dimple pattern on bearing steel flat mated with pin-on-disk. We demonstrated the lubrication mechanism for a Stribeck curve, which has a relationship between the friction coefficient and a dimensionless parameter for lubrication condition. It is found that friction coefficient is depended on the density of surface pattern. It was thus verified that micro-scale dimple could affect the friction reduction.Lubrication condition regime has an influence on the friction coefficient induced the density of micro dimple.

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알루미늄의 常溫壓接에 관한 硏究 II

  • 강문진;이철구;엄기원
    • Journal of Welding and Joining
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    • v.4 no.1
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    • pp.32-39
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    • 1986
  • This paper was studied about the influence of oxidized films on workability in cold pressure welding. In preceding studies, the principal foci of the studies about pressure welding were considered several factors(surface manufacturing methods, surface roughness, pressure welding speed and surface temperature). But the influence to the growth of oxidation have hardly known well. So the purpose of this paper consists in solving the question above and proposing the optimal states of the pressure welding. Therefore the results obtained is as the following; When the oxidation time is within about 2 minutes, the bonding strength is very good after surface manufacturing of the neighboring to be bonded. The more surfaces are fine the more bonding strength is excellent. Above all, the optimal condition of cold pressure welding is the state that the characteristic value is 38% with smooth surface and without oxidation.

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Run-to-Run Process Control and the Analysis of Process Parameters using Design of Experiment in Surface Finishing (실험계획법에 의한 파라미터 분석과 Run to Run 제어를 이용한 폴리싱 공정 제어)

  • 안병운;박성준;이상조;윤종학
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.92-96
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    • 2004
  • In this paper, polishing method using bonded magnetic abrasive particle has been applied to the micro mold polishing. Through process control using the Run-to-Run control, it tried to form the surface roughness In order to grasp the influence of the surface roughness which is reached by selection of control factor and the factor, a design of experiment was been processed. The study is processed with a purpose of to embody and to maintain the surface roughness of nano scale by the basis of an influence between a control factor and the factors which has been selected in this way. As a result, the result of the process control converged at a target value of surface roughness Ra 10nm and Rmax 50nm

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