1,626 research outputs found
Classical supravalvar aortic stenosis and peripheral pulmonary stenosis
Supravalvar aortic stenosis as well as peripheral pulmonary stenosis are rare forms of congenital
heart disease, which occur, however, relatively frequently in association. This article reports and
discusses the classical findings of SVAS and PPS upon clinical examination and imaging in a sixyear-old
girl that presented with repeated respiratory tract infections and failure to thrive.peer-reviewe
Effect of Introduction of Fault and Imperfect Debugging on Release Time
One of the most important decisions related to the efficient management of testing phase of software development life cycle is to determine when to stop testing and release the software in the market. Most of the testing processes are imperfect once. In this paper first we have discussed an optimal release time problem for an imperfect faultdebugging model due to Kapur et al considering effect of perfect and imperfect debugging separately on the total expected software cost. Next, we proposed a SRGM incorporating the effect of imperfect fault debugging and error generation. The proposed model is validated on a data set cited in literature and a release time problem is formulated minimizing the expected cost subject to a minimum reliability level to be achieved by the release time using the proposed model. Solution method is discussed to solve such class of problem. A numerical illustration is given for both type of release problem and finally a sensitivity analysis is performed
Multi-criteria media mix decision model for advertising multiple product with segment specific and mass media
Judicious media planning decisions are crucial for successful advertising of products. Media planners extensively use mathematical models supplemented with market research and expert opinion to devise the media plans. Media planning models discussed in the literature largely focus on single products with limited studies related to the multi-product media planning. In this paper we propose a media planning model to allocate limited advertising budget among multiple products advertised in a segmented market and determine the number of advertisements to be given in different media. The proposed model is formulated considering both segment specific and mass media vehicles to maximize the total advertising reach for each product. The model also incorporates the cross product effect of advertising of one product on the other. The proposed formulation is a multi-objective linear integer programming model and interactive linear integer goal programming is discussed to solve the model. A real life case study is presented to illustrate the application of the proposed model
Laser Proximity Sensor for Fuel-air Explosive Bomb
Present study deals with design and development aspects of a diode laser proximity sensorbased on principle of optical triangulation. This sensor incorporates a laser transmitter and anoptical receiver. The beam divergence of laser transmitter and look angle of receiver are orientedin such a way that they intersect at a predetermined measuring segment. The sensor can be setto give signal output at predetermined distance from the target. Theoretical studies have beencarried out to determine the minimum power required for transmitter with a trade-off between S/Nratio, aperture of receiver optics, reflectivity of target and range requirement. The scattered laserradiation from the target in this segment is utilised in deriving a signal output to detonate thebomb at a predetermined distance from the target. The laser proximity sensor has been developedfor 3 ± 0.5 m operational range and has qualified various environmental tests and live fuel-airexplosive bomb trials
Review of Grid Interconnection Requirements and Synchronization Controllers for Dispersed Minigrids
As of 2019, the world population without electricity access is estimated to 770 million with most of these communities residing in sub-Saharan Africa. Nevertheless, between 2000 and 2019 the Indian population with electricity access has grown from 43% to 99%. Minigrids have played a major role in the efforts of increasing access to electricity in rural areas. However, interconnecting minigrids to each-other or to the main grid remains still a challenge both due to lack of clear protocols and of technically matured controllers to manage the synchronization. In this paper, a review of existing interconnection guidelines is presented and their relevance for the interconnection of minigrids is assessed. Furthermore, existing synchronization controllers are reviewed highlighting their applicability for minigrids.acceptedVersio
A PERFORMANCE MODELING AND DECISION SUPPORT SYSTEM FOR A FEED WATER UNIT OF A THERMAL POWER PLANT
<p>ENGLISH ABSTRACT: The present paper discusses the performance modeling and decision support system for a feed water unit of a thermal power plant using the concept of performance analysis and modeling. A feed water unit ensures a proper supply of water for the sound functioning of a thermal power plant. The decision support system for a feed water unit has been developed with the help of performance modeling using a probabilistic approach. After drawing a transition diagram, differential equations are generated. After that, steady state probabilities are determined. Some decision matrices are also developed, which provide various performance levels for different combinations of failure and repair rates of all subsystems. Based upon various availability values obtained in decision matrices and plots of failure rates / repair rates of various subsystems, the performance of each subsystem is analyzed, and maintenance decisions are made for all subsystems.</p><p>AFRIKAANSE OPSOMMING: Vertoningsanalise en –modellering word gedoen vir die toevoerwatersisteem van ‘n termiese kragstasie. Toevoerwater is ‘n belangrike factor vir die doeltreffende bedryf van ‘n kragstasie. Die vertoningsanalise en –model is probalisties van aard. ‘n Toestandoorgangsdiagram en bypassende differensiaalvergelykings word gebruik, gevolg deur bepaling van die bestandige sisteemtoestand. Bykomende aandag word gegee aan relevante subsisteme. Die vertoning van subsisteme word gebasseer op verskeie beskikbaarheidswaardes om sodoende instandhouding to optimiseer.</p>
On the fourth-order accurate compact ADI scheme for solving the unsteady Nonlinear Coupled Burgers' Equations
The two-dimensional unsteady coupled Burgers' equations with moderate to
severe gradients, are solved numerically using higher-order accurate finite
difference schemes; namely the fourth-order accurate compact ADI scheme, and
the fourth-order accurate Du Fort Frankel scheme. The question of numerical
stability and convergence are presented. Comparisons are made between the
present schemes in terms of accuracy and computational efficiency for solving
problems with severe internal and boundary gradients. The present study shows
that the fourth-order compact ADI scheme is stable and efficient
High-energy gamma-ray emission from the inner jet of LS I+61 303: the hadronic contribution revisited
LS I+61 303 has been detected by the Cherenkov telescope MAGIC at very high
energies, presenting a variable flux along the orbital motion with a maximum
clearly separated from the periastron passage. In the light of the new
observational constraints, we revisit the discussion of the production of
high-energy gamma rays from particle interactions in the inner jet of this
system. The hadronic contribution could represent a major fraction of the TeV
emission detected from this source. The spectral energy distribution resulting
from p-p interactions is recalculated. Opacity effects introduced by the photon
fields of the primary star and the stellar decretion disk are shown to be
essential in shaping the high-energy gamma-ray light curve at energies close to
200 GeV. We also present results of Monte Carlo simulations of the
electromagnetic cascades developed very close to the periastron passage. We
conclude that a hadronic microquasar model for the gamma-ray emission in LS I
+61 303 can reproduce the main features of its observed high-energy gamma-ray
flux.Comment: 6 pages. Sligth improvements made. Accepted version by Astrophysics
and Space Scienc
Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage: Proposal of an Evidence-Based Combined Clinical and Imaging Reference Standard
Aneurysmal subarachnoid hemorrhage is associated with high morbidity and mortality, with delayed neurologic deficits from delayed cerebral ischemia contributing to a large portion of the adverse outcomes in this patient population. There is currently no consensus reference standard for establishing the diagnosis of delayed cerebral ischemia either in the research or clinical settings, ultimately limiting strategies for preventing delayed infarction and permanent neurologic deficits. There are currently both clinical and imaging-based criteria for the diagnosis of delayed neurologic deficits and vasospasm, respectively, however, neither clinical nor angiographic assessment alone has been shown to identify patients who develop adverse outcomes from delayed infarction. Thus, the purpose of this work is to propose a 3-tiered combined imaging and clinical reference standard based on evidence from the literature to standardize the diagnosis of delayed cerebral ischemia, both to allow consistency across research studies and to ultimately improve outcomes in the clinical setting
Two-Photon, Two-gluon and Radiative Decays of Heavy Flavoured Mesons
Here we present the two-photon and two-gluon decay widths of the S-wave
() and P-wave () charmonium and bottonium
states and the radiative transition decay widths of , and
systems based on Coulomb plus power form of the inter-quark potential
() with exponent . The Schrdinger equation is solved
numerically for different choices of the exponent . We employ the masses
of different states and their radial wave functions obtained from the study to
compute the two-photon and two-gluon decay widths and the E1 and M1 radiative
transitions. It is found that the quarkonia mass spectra and the E1 transition
can be described by the same interquark model potential of the with
for and for systems, while the M1
transition (at which the spin of the system changes) and the decay rates in the
annihilation channel of quarkonia are better estimated by a shallow potential
with .Comment: 27 Pages, 8 figure
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