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Institution

Texas A&M University

EducationCollege Station, Texas, United States
About: Texas A&M University is a education organization based out in College Station, Texas, United States. It is known for research contribution in the topics: Population & Finite element method. The organization has 72169 authors who have published 164372 publications receiving 5764236 citations.


Papers
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Journal ArticleDOI
TL;DR: A procedure is developed for the maximum-likelihood estimation of the unknown constants and variances included in the general mixed analysis of variance model, involving fixed and random factors and interactions, and applies to all cases where the design matrices satisfy certain conditions.
Abstract: SUMMARY A procedure is developed for the maximum-likelihood estimation of the unknown constants and variances included in the general mixed analysis of variance model, involving fixed and random factors and interactions. The method applies to all cases where the design matrices satisfy certain conditions. The consistency and asymptotic efficiency of the estimates are discussed. Tests of hypotheses and confidence regions are derived. In this paper we develop a procedure for maximum-likelihood estimation for the general mixed analysis of variance model, defined in (1) below, involving any number of fixed and random factors and possibly interactions of any order. We do not specify 'equal numbers' or indeed any other experimental balance for our procedure, but we do require that our design matrices satisfy certain conditions of estimability for the parameters. In the case of balanced designs the estimation problem for the constants and variances involved in the linear model has been extensively treated: confining ourselves to just one reference on variance estimation, optimality properties of the classical analysis of variance procedures have already been demonstrated for various balanced designs (e.g. Graybill, 1961). However, results for unbalanced factorial and nested data are much more restricted: Henderson (1953) has suggested a method of unbiased estimation of variance components for the unbalanced two-way classification but his method is computationally cumbersome for a mixed model and when the number of classes is large. Searle & Henderson (1961) have suggested a simpler method also for the unbalanced two-way classification with one fixed factor containing a moderate number of levels and a random factor permitted to have quite a large number of levels. Bush & Anderson (1963) have investigated for the two-way classification random model the relative efficiency of Henderson's (1953) method and two other methods, A and B, based on the respective methods of fitting constants and weighted squares of means described by Yates (1934) for experiments based on a fixed effects model which also provide unbiased estimates of variance components. Possibilities of generalizations are indicated. In all the above methods the estimates of any constants in the model are computed from the 'Aitken Type' weighted least squares estimators based on the exact variance-covariance matrix of the experimental responses which involves the unknown variance ratios. The estimation of the latter is then based on various unbiased procedures so that little is known about any optimality properties of any of the resulting estimators. However, all these methods reduce to the well-known procedures based on minimal sufficient statistics in the special cases of balanced designs. The method of maximum-likelihood estimation here developed differs from the above in that maximum-likelihood equations are used and solved for both the estimates of constants

614 citations

Journal ArticleDOI
TL;DR: It is shown by examples that optimum and robust controllers, designed by using the H/sub 2/, H/ sub /spl infin//, l/sup 1/, and /spl mu/ formulations, can produce extremely fragile controllers, in the sense that vanishingly small perturbations of the coefficients of the designed controller destabilize the closed-loop control system.
Abstract: We show by examples that optimum and robust controllers, designed by using the H/sub 2/, H/sub /spl infin//, l/sup 1/, and /spl mu/ formulations, can produce extremely fragile controllers, in the sense that vanishingly small perturbations of the coefficients of the designed controller destabilize the closed-loop control system. The examples show that this fragility usually manifests itself as extremely poor gain and phase margins of the closed-loop system. The calculations given here should raise a cautionary note and draw attention to the larger issue of controller sensitivity which may be important in other nonoptimal design techniques as well.

613 citations

Proceedings ArticleDOI
01 Aug 2000
TL;DR: Simulation results show that the proposed algorithm is able to schedule transmissions such that the bandwidth allocated to different flows is proportional to their weights.
Abstract: Fairness is an important issue when accessing a shared wireless channel. With fair scheduling, it is possible to allocate bandwidth in proportion to weightsof the packet flows sharing the channel. This paper presents a fully distributed algorithm for fair scheduling in a wireless LAN. The algorithm can be implemented without using a centralized coordinator to arbitrate medium access. The proposed protocol is derived from the Distributed Coordination Function in the IEEE 802.11 standard. Simulation results show that the proposed algorithm is able to schedule transmission such that the bandwidth allocated to different flows is proportional to their weights. An attractive feature of the proposed approach is that it can be implemented with simple modifications to the IEEE 802.11 standard.

612 citations

Journal ArticleDOI
TL;DR: It is envisioned that MOFs can be a promising nanoplatform by adopting advanced small molecule systems into the tunable framework with room for postsynthetic modification, following the finding of size controllability covering a broad range in the nano regime.
Abstract: The understanding of nanomaterials for targeted cancer therapy is of great importance as physical parameters of nanomaterials have been shown to be strong determinants that can promote cellular responses. However, there have been rare platforms that can vastly tune the core of nanoparticles at a molecular level despite various nanomaterials employed in such studies. Here we show targeted photodynamic therapy (PDT) with Zr(IV)-based porphyrinic metal–organic framework (MOF) nanoparticles. Through a bottom-up approach, the size of MOF nanoparticles was precisely tuned in a broad range with a designed functional motif, built upon selection of building blocks of the MOF. In particular, molecular properties of the porphyrinic linker are maintained in the MOF nanoparticles regardless of their sizes. Therefore, size-dependent cellular uptake and ensuing PDT allowed for screening of the optimal size of MOF nanoparticles for PDT while MOF nanoparticle formulation of the photosensitizer showed better PDT efficacy t...

612 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a simulation of the transition and free-molecular regime of pressure-driven liquid flow in a shear-driven and separated liquid flow model.
Abstract: Basic Concepts and Technologies * Governing Equations and Slip Models * Shear-Driven and Separated Micro Flows * Pressure-Driven Micro Flows: Slip Flow Regime * Pressure-Driven Flows: Transition and Free- Molecular Regimes * Thermal Effects in Micro Scales * Prototype Applications of Gas Micro Flows * Electrokinetically-Driven Liquid Micro Flows * Numerical Methods for Continuous Simulation * Numerical Methods for Atomistic Simulation

612 citations


Authors

Showing all 72708 results

NameH-indexPapersCitations
Yi Chen2174342293080
Scott M. Grundy187841231821
Evan E. Eichler170567150409
Yang Yang1642704144071
Martin Karplus163831138492
Robert Stone1601756167901
Philip Cohen154555110856
Claude Bouchard1531076115307
Jongmin Lee1502257134772
Zhenwei Yang150956109344
Vivek Sharma1503030136228
Frede Blaabjerg1472161112017
Steven L. Salzberg147407231756
Mikhail D. Lukin14660681034
John F. Hartwig14571466472
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20241
2023211
2022938
20218,664
20208,925
20198,426