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49
Theory of Algorithms for Unconstrained Optimization
, 1992
"... this article I will attempt to review the most recent advances in the theory of unconstrained optimization, and will also describe some important open questions. Before doing so, I should point out that the value of the theory of optimization is not limited to its capacity for explaining the behavio ..."
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Cited by 86 (1 self)
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this article I will attempt to review the most recent advances in the theory of unconstrained optimization, and will also describe some important open questions. Before doing so, I should point out that the value of the theory of optimization is not limited to its capacity for explaining the behavior of the most widely used techniques. The question
Power Modeling for High Level Power Estimation
 IEEE Transactions on Very Large Scale Integration (VLSI) Systems
, 2000
"... In this paper, we propose a modeling approach that captures the dependence of the power dissipation of a combinational logic circuit on its input/output signal switching statistics. The resulting power macromodel, consisting of a single fourdimensional table, can be used to estimate the power consu ..."
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Cited by 23 (1 self)
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In this paper, we propose a modeling approach that captures the dependence of the power dissipation of a combinational logic circuit on its input/output signal switching statistics. The resulting power macromodel, consisting of a single fourdimensional table, can be used to estimate the power consumed in the circuit for any given input/output signal statistics. Given a lowlevel (typically gatelevel) description of the circuit, we describe a characterization process by which such a table model can be automatically built. The four dimensions of our tablebased model are the average input signal probability, average input transition density, average spatial correlation coe#cient and average output zerodelay transition density. This approach has been implemented and models have been built for many benchmark circuits. Over a wide range of input signal statistics, we show that this model gives very good accuracy, with an RMS error of about 4% and average error of about 6%. Except for one...
Aggregating disparate estimates of chance
, 2004
"... We consider a panel of experts asked to assign probabilities to events, both logically simple and complex. The events evaluated by different experts are based on overlapping sets of variables but may otherwise be distinct. The union of all the judgments will likely be probabilistic incoherent. We ad ..."
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Cited by 19 (4 self)
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We consider a panel of experts asked to assign probabilities to events, both logically simple and complex. The events evaluated by different experts are based on overlapping sets of variables but may otherwise be distinct. The union of all the judgments will likely be probabilistic incoherent. We address the problem of revising the probability estimates of the panel so as to produce a coherent set that best represents the group’s expertise.
Stoichiometric model of Escherichia coli metabolism: Incorporation of growthrate dependent biomass composition and mechanistic energy requirements
 Biotech. Bioeng. 1997
"... Abstract: A stoichiometric model of metabolism was developed to describe the balance of metabolic reactions during steadystate growth of Escherichia coli on glucose (or metabolic intermediates) and mineral salts. The model incorporates 153 reversible and 147 irreversible reactions and 289 metabolit ..."
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Cited by 19 (0 self)
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Abstract: A stoichiometric model of metabolism was developed to describe the balance of metabolic reactions during steadystate growth of Escherichia coli on glucose (or metabolic intermediates) and mineral salts. The model incorporates 153 reversible and 147 irreversible reactions and 289 metabolites from several metabolic data bases for the biosynthesis of the macromolecular precursors, coenzymes, and prosthetic groups necessary for synthesis of all cellular macromolecules. Correlations describing how the cellular composition changes with growth rate were developed from experimental data and were used to calculate the drain of precursors to macromolecules, coenzymes, and prosthetic groups from the metabolic network for the synthesis of those macromolecules at a specific growth rate. Energy requirements for macromolecular polymerization and proofreading, transport of metabolites, and maintenance of transmembrane gradients were included in the model rather than a lumped maintenance energy term. The underdetermined set of equations was solved using the Simplex algorithm, employing realistic objective functions and constraints; the drain of precursors, coenzymes, and prosthetic groups and the energy requirements for the synthesis of macromolecules served as the primary set of constraints. The model accurately predicted experimentally determined metabolic fluxes for aerobic growth on acetate or acetate plus glucose. In addition, the model predicted the genetic and metabolic regulation that must occur for growth under different conditions, such as the opening of the glyoxylate shunt during growth on acetate and the branching of the tricarboxylic acid cycle under anaerobic growth. Sensitivity analyses were performed to determine the flexibility of pathways and the effects of different rates and growth conditions on the distribution of
Application of a New Adjoint Newton Algorithm to the 3D ARPS Storm Scale Model Using Simulated Data
, 1997
"... The adjoint Newton algorithm (ANA) is based on the first and secondorder adjoint techniques allowing one to obtain the "Newton line search direction" by integrating a "tangent linear model" backward in time (with negative time steps). Moreover, the ANA provides a new technique ..."
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Cited by 12 (1 self)
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The adjoint Newton algorithm (ANA) is based on the first and secondorder adjoint techniques allowing one to obtain the "Newton line search direction" by integrating a "tangent linear model" backward in time (with negative time steps). Moreover, the ANA provides a new technique to find "Newton line search direction" without using gradient information. The error present in approximating the Hessian (the matrix of second order derivatives) of the cost function with respect to the control variables in the quasiNewton type algorithm is thus completely eliminated, while the storage problem related to storing the Hessian no longer exists since the explicit Hessian is not required in this algorithm. The ANA is applied here, for the first time, in the framework of 4D variational data assimilation to the adiabatic version of the Advanced Regional Prediction System (ARPS), a 3dimensional, compressible, nonhydrostatic stormscale model. The purpose is to assess the feasibility and efficiency ...
A Solid Model Based Virtual Hairy Brush
 Proc. of Eurographics 2002, Saarbrucken
, 2002
"... We present the detailed modeling of the hairy brush used typically in Chinese calligraphy. The complex model, which includes also a model for the ink and the paper, covers the various stages of the brush going through a calligraphy process. The model relies on the concept of writing primitives, wh ..."
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Cited by 11 (4 self)
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We present the detailed modeling of the hairy brush used typically in Chinese calligraphy. The complex model, which includes also a model for the ink and the paper, covers the various stages of the brush going through a calligraphy process. The model relies on the concept of writing primitives, which are the smallest units of hair clusters, to reduce the load on the simulation. Each such primitive is constructed through the general sweeping operation in CAD and described by a NURBS surface. The writing primitives dynamically adjust themselves during the virtual writing process, leaving an imprint on the virtual paper as they move. The behavior of the brush is an aggregation of the behavior of all the writing primitives. A software system based on the model has been built and tested, which can be used as a standalone system for creating calligraphic artwork in real time or integrated as a specialeffect feature into a design software program. Samples of imitation artwork from using the system were obtained and found to be nearly indistinguishable from the real artwork.
PostLayout TimingDriven Cell Placement Using an Accurate Net Length Model with Movable Steiner Points
"... This paper presents a new algorithm for timingdriven cell placement using the notion of movable Steiner points that capture the net topology. The proposed algorithm improves the timing closure at the backend of the EDA design flow. Unlike conventional flows that perform placement and routing in tw ..."
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Cited by 10 (0 self)
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This paper presents a new algorithm for timingdriven cell placement using the notion of movable Steiner points that capture the net topology. The proposed algorithm improves the timing closure at the backend of the EDA design flow. Unlike conventional flows that perform placement and routing in two separate steps and use rough estimates of the net lengths during placement, our algorithm uses accurate net lengths by considering the net topologies during the Elmore delay calculation step and dynamically updates the routing during the concurrent placement of Steiner points and cells. The simultaneous placement and routing problem is formulated as a mathematical program with a small number of variables and solved by the HanPowell method. Experimental results demonstrate the effectiveness of the new approach compared to the conventional flows.
Adaptive traffic signal control using approximate dynamic programming. Transportation Research Part C: Emerging Technologies 17(5):456–474
, 2009
"... This paper develops an adaptive traffic signal control method that optimizes performance over time. The adaptive controller, instead of retrieving control parameters from a library according to changes in traffic, allows the value of control parameters to be slowly timevarying so that controller’s ..."
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Cited by 6 (1 self)
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This paper develops an adaptive traffic signal control method that optimizes performance over time. The adaptive controller, instead of retrieving control parameters from a library according to changes in traffic, allows the value of control parameters to be slowly timevarying so that controller’s behavior conforms to new circumstance. The adaptive controller is developed on Approximate Dynamic Programming (ADP). By replacing the lookup table containing real value of each state combination with an approximate function, ADP obviates the limit of Dynamic programming in cases of high dimensionality and of incomplete information. Approximation is progressively improved by employing online learning techniques. In this paper, we investigate ADP approach with reinforcement learning and perturbation learning. Through numerical examples, this paper shows that an adaptive controller based on ADP method is operational at isolated intersections while offering potentials for network control. It also shows that a simple linear approximation is sufficient to provide practical significance and to improve performance substantially towards theoretical limit. 1
Interactive Design of Constrained Variational Curves
, 1995
"... A constrained variational curve is a curve that minimizes some energy functional under certain interpolation constraints. Modeling curves using constrained variational principles is attractive, because the designer is not bothered with the precise representation of the curve (e.g. control points) ..."
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Cited by 5 (0 self)
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A constrained variational curve is a curve that minimizes some energy functional under certain interpolation constraints. Modeling curves using constrained variational principles is attractive, because the designer is not bothered with the precise representation of the curve (e.g. control points). Until now, the modeling of variational curves is mainly done by means of constraints. If such a curve of least energy is deformed locally (e.g. by moving its control points) the concept of energy minimization is lost. In this paper we introduce deform operators with builtin energy terms. We have tested our ideas in a prototype system for modeling uniform Bspline curves.