دانلود گزارش کارورزی و کار آموزی

نویسنده : 

Arash Rahman Æ Saeed Setayeshi Æ Mojtaba Shamsaei Zafarghandi

DOI : 10.1007/s00146-008-0186-x

Instinctive complication of human society and lack of a

natural methodology for surveying and studying complicated

social processes, has led the social scientists to take

advantage of artificial society in related categories

(Baptista et al. 2000; Bar-Yam 1997; Hales 1998, 2001;

Rahman and Setayeshi 2006; Rahman et al. 2008c).

The research presented in this article is a part of a newly

appeared course in which the agents interact with each other

for the purpose of simulating social and economic processes

(Rahman et al. 2008c; Wikipedia Encyclopedia et al. 2007).

This new course has been referred to by different titles such

as agent based communicational economics, evolutionary

economics or simulated socio-economics.

In this research, the agents in an artificial society not

only cooperate and communicate with each other in order

to receive more welfare and resources, but they contribute

one-fifth of their assets for benefit of the poor in the

society. The objective is to study the effects of a combined

mechanism (including receiving and utilizing one-fifth of

agents’ assets in addition to the existence of cooperation

and communication in an artificial society) on wealth

distribution among a population. Our study has been

accomplished by methods:

Abstract In this chapter we present the process of laser-matter interaction above the

plasma ignition threshold intensity. The physics of the pulsed laser ablation process

at high intensities is very complex since it involves, besides direct laser-solid interactions,

the process of plasma formation and expansion, and the laser-plasma interaction.

Inverse Bremsstrahlung and photoionization processes is considered to be the

main absorption mechanisms of the laser light within the ablation plumes produced

on metallic targets. Plasma kinetics including electron impact excitation/ionization

and recombination processes, as well as the energy transfer from electrons to ions and

neutral species are considered. Section 4.1 presents the main phenomena involved in

production of the ablation plasma and in laser-plasma interaction during PLA: plasma

formation and evolution. In this section, plasma heating, self focusing, critical density,

shielding, and plume expansion is discussed. Interaction of plasma plume with

obstacles is also treated in Sect. 4.1.3. Experimental methods for analyzing the main

phenomena involved in laser-plasma interaction (i.e. optical and mass spectroscopy,

high speed imaging) are presented in Sect. 4.2. The most important parameters

which characterize the laser-ablated plumes (density and the temperature) are usually

determined by optical techniques (i.e. interferometry, Thomson-scattering and plasma

spectroscopy) which can be used to reveal the characteristic features of plasma, as

well as to estimate and describe qualitatively and quantitatively its properties. The

theoretical models for describing the laser-plasma interaction allow one to estimate

the spatial–temporal distribution of the plasma parameters such as temperature, density

and pressure. Among themodels describing the dynamics of the expanding ablation

vapour/plasma plume, Monte Carlo simulations and hydrodynamic equations

approaches have been widely used. The numerical results on the ablation plasmawere

validated by comparison to the experimental data obtained by using optical emission

and absorption spectroscopy, mass spectrometry, time-of-flight and charge collection

measurements. Section 4.3 presents inmore detail theoretical results obtained within

the photo-thermal model on the characteristics of the ablation plasma in relation to

the ablation rate in nanosecond irradiation regime.

Abstract. The paper presents a naturalness preserving transform (NPT) based

collusion and compression resistant watermarking technique for video. An image

that is statistically similar to a video frame is chosen as the watermark and

this image is embedded independently in consecutive frames of the video. To

enhance the resistance to inter frame collusion based attacks, a non-overlapping

block matching is used to determine the region for placing the watermark in

consecutive frames. Only a trace of the watermark image is embedded which

enhances the robustness of the watermark to different attacks. When a frame

and the image become substantially different, another image is chosen as the

watermark. The size of the watermark determines the quality of the watermarked

video frames. Watermark extraction is blind and requires only the region

where the watermark was originally placed. The reconstruction process is

iterative and bestows immunity the watermark against noise and lossy compression.

Analysis indicates that the watermark is sufficiently immune to second

order inter-frame statistical attacks and is quite robust to image level compression.

Experimental results confirm these theoretical findings and demonstrate

the resistance of the technique to temporal frame averaging, additive noise and

JPEG based compression. However, the technique is limited by the fact that the

original video sequence (frames) is required for reconstruction based recovery

of the watermark from the watermarked video sequence.

Fracture mechanics is a branch of solid mechanics which deals with the behavior of

the material and conditions in the vicinity of a crack and at the crack tip. While the

concept of linear elastic fracture mechanics has been well developed for more than

past 40 years and successfully applied to metallic structures, several civil engineering

materials such as cementitious materials, rocks, and fiber-reinforced composites

commonly known as quasibrittle need a different fracture mechanics approach to

model the fracture process. Cementitious materials can be modeled at various scales

like the nano-, micro-, meso-, and macrolevels. At mesolevel, they can be considered

as a two-phase particulate composite, i.e., the matrix and the reinforcement.

In the cement pastes, mortar, and concrete, the matrices can be considered as the

hydrated cement gels, cement paste, and mortar, respectively, whereas the reinforcements

in the corresponding materials can be taken as unhydrated cement particles,

fine aggregates, and coarse aggregates.

A B S T R A C T

Many have speculated about the current state of Internet

advertising (IA), how it compares to advertising in general (GA),

and its implications for traditional marketing models and practices.

Although many estimates exist regarding who uses the Internet as

well as guidelines about how best to design IA, little is known

about Internet users’ attitudes toward IA, much less what

characterizes these attitudes. To test this, a national sample of over

400 participants with at least some exposure to the Internet was

surveyed. The results revealed no majority opinion of IA:

approximately a third of respondents liked, disliked, and felt

neutrally toward IA, respectively. A regression analysis indicated that

enjoyment of looking at Internet advertisements, its informativeness,

and its utility for making behavioral (purchasing) decisions . . .