1,002 research outputs found
Controlled one dimensional diffusions with switching costsâaverage cost criterion
AbstractThis paper deals with a one-dimensional controlled diffusion process on a compact interval with reflecting boundaries. The set of available actions is finite and the action can be changed only at countably many stopping times. The cost structure includes both a continuous movement cost rate depending on the state and the action, and a switching cost when the action is changed. The policies are evaluated with respect to the average cost criterion. The problem is solved by looking at, for each stationary policy, an embedded stochastic process corresponding to the state intervals visited in the sequence of switching times. The communicating classes of this process are classified into closed and transient groups and a method of calculating the average cost for the closed and transient classes is given. Also given are conditions to guarantee the optimality of a stationary policy. A Brownian motion control problem with quadratic cost is worked out in detail and the form of an optimal policy is established
A simulation-based aid for organisational decision-making
Effective decision-making of modern organisation often requires deep understanding of various aspects of organisation such as organisational goals, organisational structure, business-as-usual operational processes. The large size of the organisation, its socio-technical characteristics, and fast business dynamics make this endeavor challenging. Industry practice relies on human experts for comprehending various aspects of organisation thus making organisational decision-making a time-, effort- and intellectually-intensive endeavor. We are working on a specific instance of this problem in bespoke software development space. This paper proposes
a model-based simulation approach to organisational decision-making. We illustrate how this is applied to a real life problem from software service industr
Galactic Foreground Constraints from the Python V Cosmic Microwave Background Anisotropy Data
We constrain Galactic foreground contamination of the Python V cosmic
microwave background anisotropy data by cross correlating it with foreground
contaminant emission templates. To model foreground emission we use 100 and 12
m dust emission templates and two point source templates based on the PMN
survey. The analysis takes account of inter-modulation correlations in 8
modulations of the data that are sensitive to a large range of angular scales
and also densely sample a large area of sky. As a consequence the analysis here
is highly constraining. We find little evidence for foreground contamination in
an analysis of the whole data set. However, there is indication that
foregrounds are present in the data from the larger-angular-scale modulations
of those Python V fields that overlap the region scanned earlier by the UCSB
South Pole 1994 experiment. This is an independent consistency cross-check of
findings from the South Pole 1994 data.Comment: 15 pages, 1 figure, ApJ accepted versio
Unveiling Advanced Computational Applications in Quantum Computing: A Comprehensive Review
The field of advanced computing applications could experience a significant impact from quantum computing, which is a rapidly developing field with the potential to revolutionize numerous areas of science and technology. In this review, we explore into the various ways in which complex computational problems could be tackled by utilizing quantum computers, including machine learning, optimization, and simulation. One potential application of quantum computers is in machine learning, where they could be used to improve the accuracy and efficiency of algorithms. Complex optimization problems, such as those encountered in logistics and finance, can be addressed using quantum computers as well. Furthermore, the utilization of quantum computers could enable the simulation of intricate systems, such as molecules and materials, leading to significant applications in fields like Physics and Material Technology. Although quantum computers are currently in the early stages of development, they possess the potential to propel numerous areas of science and technology forward in a significant manner. Further research and development are needed to fully realize the potential of quantum computing in the field of advanced computing applications
Ammonia-hyperproducing bacteria from New Zealand ruminants
Pasture-grazed dairy cows, deer, and sheep were tested for the presence of ammonia-hyperproducing (HAP) bacteria in roll tubes containing a medium in which tryptone and Casamino Acids were the sole nitrogen and energy sources. Colonies able to grow on this medium represented 5.2, 1.3, and 11.6% of the total bacterial counts of dairy cows, deer, and sheep, respectively. A total of 14 morphologically distinct colonies were purified and studied further. Restriction fragment length polymorphisms of 16S rRNA genes indicated that all isolates differed from the previously described HAP bacteria,Clostridium aminophilum, Clostridium sticklandii, and Peptostreptococcus anaerobius. Carbon source utilization experiments showed that five isolates (C2, D1, D4, D5, and S1) were unable to use any, or very few, of the carbon sources tested. Biochemical tests and phylogenetic analyses of 16S ribosomal DNA sequences indicated that all isolates were monensin sensitive; that D1 and S1 belonged to the genusPeptostreptococcus, that D4 and D5 belonged to the familyBacteroidaceae, where D4 was similar to Fusobacterium necrophorum; and that C2 was most similar to an unidentified species from the genus Eubacterium. Growth on liquid medium containing tryptone and Casamino Acids as the sole nitrogen and energy source showed that D1, D4, and S1 grew rapidly (specific growth rates of 0.40, 0.35, and 0.29 hâ1, respectively), while C2 and D5 were slow growers (0.25 and 0.10 hâ1, respectively). Ammonia production rates were highest in D1 and D4, which produced 945.5 and 748.3 nmol/min per mg of protein, respectively. Tests of individual nitrogen sources indicated that D1 and D4 grew best on tryptone, S1 grew equally well on Casamino Acids or tryptone, and C2 and D5 grew poorly on all nitrogen sources. The intact proteins casein and gelatin did not support significant growth of any of the isolates. These isolates extend the diversity of known HAP rumen bacteria and indicate the presence of significant HAP bacterial populations in pasture-grazed New Zealand ruminants
Median Statistics, H_0, and the Accelerating Universe
(Abridged) We develop median statistics that provide powerful alternatives to
chi-squared likelihood methods and require fewer assumptions about the data.
Applying median statistics to Huchra's compilation of nearly all estimates of
the Hubble constant, we find a median value H_0=67 km/s/Mpc. Median statistics
assume only that the measurements are independent and free of systematic
errors. This estimate is arguably the best summary of current knowledge because
it uses all available data and, unlike other estimates, makes no assumption
about the distribution of measurement errors. The 95% range of purely
statistical errors is +/- 2 km/s/Mpc. The statistical precision of this result
leads us to analyze the range of possible systematic errors in the median,
which we estimate to be roughly +/- 5 km/s/Mpc (95% limits), dominating over
the statistical errors. A Bayesian median statistics treatment of high-redshift
Type Ia supernovae (SNe Ia) apparent magnitude versus redshift data from Riess
et al. yields a posterior probability that the cosmological constant Lambda > 0
of 70 or 89%, depending on the prior information used. The posterior
probability of an open universe is about 47%. Analysis of the Perlmutter et al.
high-redshift SNe Ia data show the best-fit flat-Lambda model favored over the
best-fit Lambda = 0 open model by odds of 366:1; corresponding Riess et al.
odds are 3:1 (assuming prior odds of 1:1).Median statistics analyses of the SNe
Ia data do not rule out a time-variable Lambda model, and may even favor it
over a time-independent Lambda and a Lambda = 0 open model.Comment: Significant revisions include discussion of systematic errors in the
median of H_0. Accepted for publication in The Astrophysical Journal, v548,
February 20, 2001 issue. 47 pages incl. figures and table
FORMULATION AND IN VITROEVALUATION OF FLOATING TABLETS OF CEFPODOXIME PROXETIL
Objective: The objective of research work was to formulate and evaluate the floating drug delivery system containing Cefpodoxime Proxetil using polymer HPMC K4M, Guar Gum.Methods: Effervescent floating tablets containing Cefpodoxime proxetil were prepared by direct compression technique using varying concentrations of different grades of polymer.Results: Physical parameters like hardness, weight variation, thickness and friability were within pharmacopoeial limit. Percentage drug content in all floating tablet formulations was found to be 90% to 110%. The floating time was found to be more than 12 H. floating lag time was found to be 10ñ2.99 second. Formulation batch F8 was selected as an optimum formulation, as possessing less disintegration time, higher water absorption ratio and good content uniformity i.e. within acceptable limit.% drug release of formulation batch F8 was found to be 96.66% in 0.1 N HCL.Conclusion: The FT-IR studies of batch F8 was carried out which showed the peak values within the spectrum corresponding to the peak values of pure drug
Effects of Foreground Contamination on the Cosmic Microwave Background Anisotropy Measured by MAP
We study the effects of diffuse Galactic, far-infrared extragalactic source,
and radio point source emission on the cosmic microwave background (CMB)
anisotropy data anticipated from the MAP experiment. We focus on the
correlation function and genus statistics measured from mock MAP
foreground-contaminated CMB anisotropy maps generated in a spatially-flat
cosmological constant dominated cosmological model. Analyses of the simulated
MAP data at 90 GHz (0.3 deg FWHM resolution smoothed) show that foreground
effects on the correlation function are small compared with cosmic variance.
However, the Galactic emission, even just from the region with |b| > 20 deg,
significantly affects the topology of CMB anisotropy, causing a negative genus
shift non-Gaussianity signal. Given the expected level of cosmic variance, this
effect can be effectively reduced by subtracting existing Galactic foreground
emission models from the observed data. IRAS and DIRBE far-infrared
extragalactic sources have little effect on the CMB anisotropy. Radio point
sources raise the amplitude of the correlation function considerably on scales
below 0.5 deg. Removal of bright radio sources above a 5 \sigma detection limit
effectively eliminates this effect. Radio sources also result in a positive
genus curve asymmetry (significant at 2 \sigma) on 0.5 deg scales. Accurate
radio point source data is essential for an unambiguous detection of CMB
anisotropy non-Gaussianity on these scales. Non-Gaussianity of cosmological
origin can be detected from the foreground-subtracted CMB anisotropy map at the
2 \sigma level if the measured genus shift parameter |\Delta\nu| >= 0.02 (0.04)
or if the measured genus asymmetry parameter |\Delta g| >= 0.03 (0.08) on a 0.3
(1.0) deg FWHM scale.Comment: 26 pages, 7 figures, Accepted for Publication in Astrophysical
Journal (Some sentences and figures modified
Using White Dish CMB Anisotropy Data to Probe Open and Flat-Lambda CDM Cosmogonies
We use data from the White Dish experiment to set limits on cosmic microwave
background radiation anisotropies in open and spatially-flat-Lambda cold dark
matter cosmogonies. We account for the White Dish calibration uncertainty, and
marginalize over the offset and gradient removed from the data. Our 2-sigma
upper limits are larger than those derived previously. These upper limits are
consistent with those derived from the -DMR data for all models tested.Comment: 17 pages of latex. Uses aasms4.sty. 4 figures included. Submitted to
ApJ
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