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91.
We apply the recently improved version of the 0–1 test for chaos to real experimental time series of laser droplet generation process. In particular two marginal regimes of dripping are considered: spontaneous and forced dripping. The outcomes of the test reveal that both spontaneous and forced dripping time series can be characterized as chaotic, which coincides with the previous analysis based on nonlinear time series analysis. 相似文献
92.
93.
The Raman spectra of mixed crystals of [(NH4)1?x K x ]2 SO4 in the region 50–3400 cm?1 at 293 K and below 223 K have been reported. At room temperature 293 K, as the concentration of K+ ion increases in the crystal up to 50%, the frequencies of the totally symmetric vibrations of SO 4 2? and NH 4 + ions increase and thereafter the frequency of SO 4 2? vibration decreases and attains the value in K2SO4. This change in frequency up to 50% of potassium concentration is due to the breaking of hydrogen bonds of the type N-H...O. The behaviour of Raman intensities of A g (v 1) mode of SO 4 2? for various concentrations (x=0, 0·03, 0·11, 0·5, 0·85) suggest that the phase transition changes from first order type to one of second order. The phase transition in mixed crystals of [(NH4)1?x K x ]2 SO4 can be a cooperative phenomenon arising from a coupling between (NH4)+ ions through hydrogen bonds with the distorted SO 4 2? ions in the low temperature phase. 相似文献
94.
In a Talbot interferometer the self image of a periodic pattern, such as a Ronchi ruling of period d, illuminated by a monochromatic plane wavefront of wavelength λ, is formed at distances which are integral multiples of 2d2/λ. A refracting object placed in front of the Ronchi ruling distorts the self image. A computer generated pattern can be designed, such that, when placed in a self imaging plane, a uniform intensity or a distinct moire pattern characterising a standard object is obtained. A method of computing the required patterns and experimental results for some aspherical objects are described. 相似文献
95.
We consider the control of an infinite capacity shuttle which transports passengers between two terminals. The passengers
arrive at each terminal according to a compound Poisson process and the travel time from one terminal to the other is a random
variable following an arbitrary distribution. The following control limit policy is considered: dispatch the shuttle at terminali, at the instant that the total number of passengers waiting at terminali reaches or exceeds a predetermined control limitm
i
. The objective of this paper is to obtain the mean waiting time of an arbitrary passenger at each terminal for given control
valuesm
1 andm
2. We also discuss a search procedure to obtain the optimal control values which minimize the total expected cost per unit
time under a linear cost structure. 相似文献
96.
We consider the problem of determining lot sizes of multiple items that are manufactured by a single capacitated facility. The manufacturing facility may represent a bottleneck processing activity on the shop floor or a storeroom that provides components to the shop floor. Items flow from the facility to a downstream facility, where they are assembled according to a specified mix. Just-in-time (JIT) manufacturing requires a balanced flow of items, in the proper mix, between successive facilities. Our model determines lot sizes of the various items based on available capacity and four attributes of each item: demand rate, holding cost, set-up time and processing time. Holding costs for each item accrue until the appropriate mix of items is available for shipment downstream. We develop a lot-sizing heuristic that minimizes total holding cost per time unit over all items, subject to capacity availability and the required mix of items. 相似文献
97.
An index fund is a portfolio of shares designed to replicate the investment performance of a market index. The index represents the behaviour of the market as a whole. This paper describes the selection of an index fund which minimizes expected tracking error. Using a multivariate model of returns on shares, a development of a univariate model by Taylor, the selection problem is formulated as a quadratic programme. The effects of various constraints on tracking error are demonstrated. Several policies for the readjustment of a fund are examined in the context of the differing objectives of fund managers. As a general rule, regular readjustment is shown to be a more expensive policy than irregular updating. 相似文献
98.
This paper is concerned with a combined production-transportation scheduling problem. The problem comprises a simple, two-machine, automated manufacturing cell, which either stands alone or is a subunit of a complete flexible manufacturing system. The cell consists of two machines in series with a dedicated part-handling device such as a crane or robotic arm for transferring parts from the first machine to the second. The loading of a new piece on the first machine and the ejection of a finished piece from the second machine are performed by dedicated automated mechanisms. The introduction of parts into the system is done n at a time, whereby the parts are reshuffled into a sequence that minimizes completion time. All processing and transfer times are considered deterministic—a reasonable assumption for a cell comprising a robotic transfer device and two CNC machining units. What complicates the problem is the assumption of a non-negligible time for the transfer device to return (empty) from the second machine to the first. The operation is a generalization of a two-machine flowshop problem, and is formulated as a specially structured, asymmetric travelling salesman problem. An approximate polynomial time 0(n log n) algorithm is proffered. The procedure incorporates a lower bound using the Gilmore–Gomory algorithm for the no-wait, two-machine flowshop problem. 相似文献
99.
Summary. In this paper, we derive a posteriori error estimates for the finite element approximation of quadratic optimal control problem
governed by linear parabolic equation. We obtain a posteriori error estimates for both the state and the control approximation.
Such estimates, which are apparently not available in the literature, are an important step towards developing reliable adaptive
finite element approximation schemes for the control problem.
Received July 7, 2000 / Revised version received January 22, 2001 / Published online January 30, 2002
RID="*"
ID="*" Supported by EPSRC research grant GR/R31980 相似文献
100.