دانلود گزارش کارورزی و کار آموزی

چکیده : 

Experimental data are now widely available for the size of craters resulting from hypervelocity impacts of millimetre scale projectiles

onto water ice targets. At such size scales the bowl shaped crater formed in ductile materials, or in larger scale impacts, is here surrounded

by a large spallation zone due to the brittle nature of the ice. Modelling of these impacts therefore has to take account of this

spallation. Here we used the iSALE2 hydrocode to simulate such impacts and compared the results to experimental data. We found that

it was possible to reproduce the experimental data over a range of speeds (1–7 km s1) for aluminium and copper projectiles. Initially, to

reproduce the large spallation regions around the craters it was assumed that above a certain degree of damage, material was removed by

spallation. However this simple one-parameter model failed to model the crater depth adequately. Accordingly, to obtain the best agreement

of the simulations with the experimental data, a two-step ice strength was introduced, whereby above a critical amount of damage

(0.95), the yield strength reduced from 1 MPa (intact) to 70 kPa (damaged). As a result, experimental data for crater depth and diameter

and the results of the simulations agree to within 6% for diameter and 5% for depth over the impact energy range used in the experiments

(1–240 J).

چکیده : 

A long temporal series of simulated ionograms was generated with a superimposed secular variation of 14 km/century on the hmF2

parameter. These ionograms were interpreted by the automatic scaling program Autoscala. By applying four different empirical formulas,

four artificial series of hmF2 were generated and then processed with the same methods used by other authors for real data sets. Data

analysis of the simulated ionograms revealed the artificially imposed long-term trend. These results lead to the conclusion, that regardless

of the empirical formula used, the accuracy of hmF2 from ionosonde measurements would be adequate to observe a long-term trend of

14 km/century.

چکیده : 

The Wind spacecraft’s Faraday cups (FC) continue to produce high-quality, in situ observations of thermal protons (i.e., ionized

hydrogen) and a-particles (i.e., fully ionized helium) in the solar wind. By fitting a Wind/FC ion spectrum with a model velocity distribution

function (VDF) for each particle species, values for density, bulk velocity, and temperature can be inferred. Incorporating measurements

of the background magnetic field from the Wind Magnetic Field Investigation (MFI) allows perpendicular and parallel

temperature components to be separated. Prior implementations of this analysis averaged the higher-cadence Wind/MFI measurements

to match that of the Wind/FC ion spectra. However, this article summarizes recent and extensive revisions to the analysis software that,

among other things, eliminate such averaging and thereby account for variations in the direction of the magnetic field over the time taken

to measure the ions. A statistical comparison reveals that the old version consistently underestimates the temperature anisotropy of ion

VDF’s: averaging over fluctuations in the magnetic field essentially blurs the perpendicular and parallel temperature components, which

makes the plasma seem artificially more isotropic. The new version not only provides a more accurate dataset of ion parameters (which is

well suited to the study of microkinetic phenomena), it also demonstrates a novel technique for jointly processing particle and field data.

Such methods are crucial to heliophysics as wave-particle interactions are increasingly seen as playing an important role in the dynamics

of the solar wind and similar space plasmas.

چکیده :

This paper proposes a benchmark for comparing SES gradients across countries, based on

gross domestic product apportioned to members of differing wealth categories within

countries. Using this approach, we estimate absolute wealth in 360 populations in 36

developing countries and model its relationship with overweight (BMI 25) among nonpregnant

women ages 18–49. A simple model based on absolute wealth alone strongly

predicts odds of overweight (), a relationship that holds both between countries

and between different groups in the same country (10 populations for each of 36

countries). Moreover, world region modifies this relationship, accounting for an additional

22% of variance (). This allows us to extract a basic pattern: rising rates of

overweight in lower and middle income countries closely track increasing economic

resources, and the shape of that gradient differs by region in systematic ways.

چکیده : 

This paper looks at health outcomes, health behaviors, and health screening with respect

to participation in Early Childhood Care and Education. With information on health status

at multiple periods in time, we are able to look at whether healthier children select into

early childhood education (as measured by center-based preschool care and Head Start),

as well as whether early childhood education has immediate and near-term effects on a

range of health status measures. There is some evidence that child obesity is ameliorated

by participation in center-based preschool or Head Start and this finding is supported by

clear evidence of improved nutrition and increased levels of health screening. Effects on

other health outcomes such as asthma, ear infections, and respiratory problems may be

partially masked by unobserved heterogeneity

چکیده : 

In order to protect water and other sensitive areas from spray drift, and make the best use of mitigation

measures, an evaluation of drift risk should be made prior to a spray application. The objective of this

work was to develop a practical, interactive tool to evaluate the risk of spray drift for specific weather

and field situation, and propose effective measures to mitigate this risk. This should help the pesticide

user to make better decisions in order to reduce potential spray drift contamination. The Drift Evaluation

Tool (DET) is intended to be used by the pesticide users and advisors, and hence raise their awareness on

the effect of factors influencing spray drift and on mitigation measures to reduce drift risk. The aim was to

offer a simple and practical application software that would be user-friendly and educative to encourage

its wide use. The operator communicates with the software via its simple and intuitive visual interface.

He is guided through three pages and asked to select in the proposed lists of options the parameters that

best reflect his actual situation. On the first page the user determines the application site: within or

beyond the zone of awareness (buffer zone plus boom width), i.e. whether or not risk of drift need to

be considered. On the next page he determines actual weather and field conditions: wind direction

and velocity, air temperature and humidity, crop height and adjacent structures. Once the items are

selected the Drift Risk Value SITUATION (%) (DRVS) is calculated and expressed both in figure and graphically.

Thus, the user can see directly how variations in weather and field conditions may affect the spray

drift risk. Depending on the risk level appropriate practical recommendation appears on the screen.

چکیده : 

This paper describes SOLARCALC 7.0, a new implementation of a computer program designed for the analysis

of hemispherical photographs. Our aim was to recode, optimize, enhance and recompile the previous version

of SOLARCALC program using REALBASIC, a modern, cross-platform BASIC language programming environment.

The main improvements of the new version are described as follows: Programming and layout – a

revision and enhancement of the original source code in a new, redesigned and user-friendly interface;

Calculations – the possibility of allowing calculations for a growing season length, the possibility of defining

the number of zenith and azimuth angles used for the calculations, the calculations of direct, indirect

and total site factors, the inclusion of two versions of the Standard Overcast (SOC) sky weighting formula,

the ability to compute leaf area index using two different methods and to compute the sky view factor,

the ability to compute the total daily extraterrestrial radiation, the capacity of handling grayscale and

color images and to manually or automatically threshold the images. The performance of the new version

of SOLARCALC was assessed using a series of hemispherical images taken along a light gradient. Comparisons

of calculated canopy light and structural indices between the new version of the program and GLA (Gap

Light Analyser) show highly significant positive correlations (), indicating that SOLARCALC performs

similarly to GLA across a variety of forest canopy openings. The incorporated modifications in the new version

of the program allows for more detailed and more versatile analyses of hemispherical photographs

and as such, represent a significant improvement in comparison with the previous version of the program.

Finally, one of the most salient feature of SOLARCALC compared to other similar software is the possibility

of using compiled versions of the program compatible with Macintosh, Windows and Linux/Unix

operating systems, localised in English, French and Spanish languages.

چکیده : 

Attribute selection is one of the important problems encountered in pattern recognition, machine learning,

data mining, and bioinformatics. It refers to the problem of selecting those input attributes or features

that are most effective to predict the sample categories. In this regard, rough set theory has been shown

to be successful for selecting relevant and nonredundant attributes from a given data set. However, the

classical rough sets are unable to handle real valued noisy features. This problem can be addressed by

the fuzzy-rough sets, which are the generalization of classical rough sets. A feature selection method is

presented here based on fuzzy-rough sets by maximizing both relevance and significance of the selected

features. This paper also presents different feature evaluation criteria such as dependency, relevance,

redundancy, and significance for attribute selection task using fuzzy-rough sets. The performance of different

rough set models is compared with that of some existing feature evaluation indices based on the

predictive accuracy of nearest neighbor rule, support vector machine, and decision tree. The effectiveness

of the fuzzy-rough set based attribute selection method, along with a comparison with existing feature

evaluation indices and different rough set models, is demonstrated on a set of benchmark and microarray

چکیده : 

This letter presents correction of E-model for the quality estimation of the packetized speech signal

in the case of burst packet loss. The current estimation depends on the method of calculation, i.e. on

the duration of speech signal segment, which is to be packetized by one packet. This inconsistency in

estimation is described, and the correction of this imperfection is proposed. It is explained that the Packetloss

Robustness Factor is dependent, besides coder, on the duration of speech signal segment, which is

packetized by one packet.