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221.
Abraham Y Salman H Suwinska K Eichen Y 《Chemical communications (Cambridge, England)》2011,47(21):6087-6089
Cyclo[2]benzimidazole is a new host for anions that turns on its luminescence up to 150 fold upon binding. Photoexcited cyclo[2]benzimidazole undergoes an efficient non-radiative deactivation through an excited-state intramolecular proton-transfer (ESIPT) mechanism. Upon binding an anion, the ESIPT pathway is blocked, resulting in an increase in the luminescence efficiency. 相似文献
222.
This paper describes the experimental procedure to identify the predominant frequencies of the high speed testing machine
by conducting modal analysis. The effects due to the predominant frequencies of the system and loading rate on the magnitude
of system ringing and the flow stress were analyzed by using a single degree-of-freedom (SDOF) spring-mass-damper model. The
system was then used to study the dynamic tensile behavior of two engineering materials, i.e., polyethylene (PE) fabric-cement
composite and Alkaline Resistant (AR) glass fabrics at an intermediate strain rate. The stress oscillations in the response
of these materials due to system ringing were addressed. The failure behavior of each material was studied by examining high
speed digital camera images of specimens during the test. The validity of the dynamic tensile tests was investigated by examining
the condition of dynamic stress equilibrium—a criterion used in split Hopkinson pressure bar (SHPB) tests. The results show
that the quantitative criterion for a valid SHPB test is also applicable to dynamic tensile tests of these materials at the
intermediate strain rate. 相似文献
223.
Conventional training simulators commonly use a hexapod configuration to provide motion cues. While widely used, studies have
shown that hexapods are incapable of producing the range of motion required to achieve high fidelity simulation required in
many applications. A novel alternative is the Atlas motion platform. This paper presents a new generalized kinematic model
of the platform which can be applied to any spherical platform actuated by three omnidirectional wheels. In addition, conditions
for slip-free and singularity-free motions are identified. Two illustrative examples are given for different omnidirectional
wheel configurations. 相似文献
224.
Lara Turner Abraham P. Punnen Yash P. Aneja Horst W. Hamacher 《Mathematical Methods of Operations Research》2011,73(1):19-27
In the generalized balanced optimization problem (GBaOP) the objective value \({\max_{e \in S}{|c(e)-k\max(S)|}}\) is minimized over all feasible subsets S of E = {1, . . . , m}. We show that the algorithm proposed in Punnen and Aneja (Oper Res Lett 32:27–30, 2004) can be modified to ensure that the resulting solution is indeed optimal. This modification is attained at the expense of increased worst-case complexity, but still maintains polynomial solvability of various special cases that are of general interest. In particular, we show that GBaOP can be solved in polynomial time if an associated bottleneck problem can be solved in polynomial time. For the solution of this bottleneck problem, we propose two alternative approaches. 相似文献
225.
Exact and approximate solutions for the reliability of a circular shaft, simultaneously subjected to a bending moment and a torque, are derived and compared. The closed-form solution is obtained in terms of an equivalent bending moment having a noncentral chi-square distribution, whereas the approximate solution is derived via the Hasofer-Lind reliability index. Comparison shows a remarkably high accuracy of the index.On leave from the Technion, Israel Institute of Technology, Haifa, Israel 相似文献
226.
Christophe Abraham 《Journal of multivariate analysis》2005,95(1):50-65
We provide the rate of convergence of the Bayes action derived from non smooth loss functions involved in Bayesian robustness. Such loss functions are typically not twice differentiable but admit right and left second derivatives. The asymptotic limit of three measures of global robustness is given. These measures are the range of the Bayes actions set associated with a class of loss functions, the maximum regret of using a particular loss when the subjective loss belongs to a given class and the range of the posterior expected loss when the loss ranges over a given class. An application to prior robustness with density ratio classes is provided. 相似文献
227.
We explore the consequences of certain commutativity hypotheses on a single nilpotent element or the set N of all nilpotent elements. We give several sufficient conditions for N to be an ideal. We present some nontrivial examples, including an example in which N is commutative (in fact, N
2 = {0}) and N is not an ideal.
Received: April 27, 2006. Revised: July 31, 2006. 相似文献
228.
We present a new approach that permits efficient performance analysis of kanban systems with general demand processes, material
arrival processes, and service times. The approach is based on parametric characterization of the traffic processes (arrival
and departure) in the network and uses two-moment approximations to estimate performance measures at individual stations.
We derive traffic flow constraints that are particular to closed queuing networks with synchronization stations and use these
to establish relationships between the parameters characterizing arrival and departure processes at the stations in the network.
The resultant set of non-linear equations is solved to estimate network performance measures. Numerical studies show that
the approach is not only fast but also reasonably accurate when compared to simulation. These studies also provide insights
with respect to the impact of different types of variability on the performance of a kanban system. This work also provides
a fundamental building block that can be used in the analysis of multi-stage kanban systems.
AMS Subject Classifications 68M20, 60K20, 90B05, 90B30 相似文献
229.
Abraham Neyman 《International Journal of Game Theory》1997,26(2):223-227
Any correlated equilibrium of a strategic game with bounded payoffs and convex strategy sets which has a smooth concave potential, is a mixture of pure strategy profiles which maximize the potential. If moreover, the strategy sets are compact and the potential is strictly concave, then the game has a unique correlated equilibrium. 相似文献
230.
Martin Dyer Abraham D. Flaxman Alan M. Frieze Eric Vigoda 《Random Structures and Algorithms》2006,29(4):450-465
We analyze Markov chains for generating a random k‐coloring of a random graph Gn,d/n. When the average degree d is constant, a random graph has maximum degree Θ(log n/log log n), with high probability. We show that, with high probability, an efficient procedure can generate an almost uniformly random k‐coloring when k = Θ(log log n/log log log n), i.e., with many fewer colors than the maximum degree. Previous results hold for a more general class of graphs, but always require more colors than the maximum degree. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2006 相似文献