The growing interest in the use of chaotic techniques for enabling secure communication in recent years has been motivated by the emergence of a number of wireless services which require the service provider to provide low bit error rates (BER) along with information security. This paper investigates the feasibility of using chaotic communications over Multiple-Input-Multiple-Output (MIMO) channels. While the use of Chaotic maps can enhance security, it is seen that the overall BER performance gets degraded when compared to conventional communication schemes. In order to overcome this limitation, we have proposed the use of a combination of Chaotic modulation and Alamouti Space Time Block Code. The performance of Chaos Shift Keying (CSK) with 2×1 and 2×2 Alamouti schemes for different chaotic maps over wireless channels has been studied. It has been shown that the use of these schemes can …
Las diferencias entre el pretérito perfecto simple y el imperfecto son uno de los temas más complejos de la lengua española, no sólo para el estudiante, sino para el profesor, puesto que sistematizar los casos y hacerlos fácilmente comprensibles al alumno es tarea difícil. Los profesores de lengua, cuyas investigaciones han dado lugar a una serie de teorías y de corrientes metodológicas y didácticas que permiten enfocar la enseñanza de una lengua extranjera de manera muy distinta a como se hacía tradicionalmente. Vamos a repasar muy brevemente cuáles son estas teorías.
En primer lugar es necesario señalar en qué consiste el aprendizaje de una segunda lengua:
"El aprendizaje de una segunda lengua (L2) es el
... Show MorePsoriasis is a long-lasting autoimmune disease that is characterized by swollen skin patches. Normally, these skin patches are dark, swollen, itchy and scaly. The single application of the innate TLR7/8 ligand Imiquimod (IMQ) in mice easily induces a dermatitis that closely resembles human psoriasis, critically dependent on the axis of IL-23/IL-17. Artemisia dracunculus prepared as an ointment and has been used topically to mice before imiquimod application. The results of the current study showed that A. dracunculus ointment can significantly reduce psoriasis area and severity index in (A. dracunculus ointment + imiquimod group as compared with both control group and (vehicle ointment + imiquimod) group.
Background: In dentistry, dentist takes the advantages of soft lining materials due to the viscoelastic properties. The major problem is the adhesion of the soft liner with the denture base material. Materials and Methods: Heat cured of high impact acrylic resin specimens prepared with dimensions 75x13x13mm for shear bond strength test, soft lining material (Refit and Mollosil) with a 3-mm thickness and used to join each two acrylic blocks. Also four specimens with the same previous dimensions utilized for chemical and physical surface analysis. The specimens grouped as control (without plasma) and experiment (with oxygen plasma) treated high impact acrylic specimens. Results: Plasma treatment increased the shear bond strength for both Refi
... Show MoreFour samples of the Se55S20Sb15Sn10 alloy were prepared using the melting point method. Samples B, C and D were irradiated with (6.04×1010, 12.08×1010 and 18.12×1010 (n.cm-2s -1 ) of thermal neutron beam from a neutron source (241Am-9Be) respectively, while sample A was left not irradiated. The electrical properties were assessed both before and after the radiation. All irradiated and non-irradiated samples show three conduction mechanisms, at low temperatures, electrical conductivity is achieved by electron hopping between local states near the Fermi level. At intermediate temperatures, conduction occurs by the jumping of electrons between local states at band tails. At high temperatures, electrons transfer between extended stat
... Show MoreThis research aims to:
1 – Make a proposed module for (aesthetics) for the second stage - Department of Art Education under education theories.
2 - Verification from the effect of the proposed module on student achievement and motivation towards learning aesthetics material.
To verification the second goal we wording these two hypotheses:
1- There are no individual differences with statistically significant at level (0.05) between the student's scores average. (Experimental group ) who studied according to the proposed module and the average student's scores (control group) who studied in the usual way for the achievement test for the Aesthetics material.
2- There are no individual differences with statistically signifi
This study aimed identify the teachers of sociology. In the development of creative thinking. I have students in middle school .llvra literary. In schools. Second Karkh From the perspective of the teachers and the students themselves numbered (41), a teacher and a school. As The study population encompassed of some students the fourth and fifth preparatory stage in the Karkh II schools, totaling 200 male and female students. As the study sample were consisted of (7) and a teacher (34) and accented (85) of male students (115) were female student The researcher the questionnaire which consisted of (39) items And to achieve the objectives of the study it was ascertained sincerity And stability. And
... Show MoreThe aim of this research is to show the level of banking leadership trends in the importance of organizational confidence and its reflection in the dimensions of the strategic position the research was applied in a bank (Al- Mansour Investment, Business Bay), and the Questionnaire Was adopted as a tool to collect data and information from the number of the sample (15) who are in allocation (Department Manager, Department Manager Department Manager, Division Officer, Unit Officer) and he used the statistical program (spss) to calculate (standard deviation, arithmetic mean, percentages, regression, analysis,F-test coefficient of determination R2, Coefficieent, square Kay and the research reached a number of conclusions, the mos
... Show MoreThe issue of Palestinian prisoners inside the prisons of the Israeli occupation is considered
a humanitarian issue par excellence، as it affects every Palestinian family as a
result of the absence of a husband، wife or son.
Almost no Palestinian house is vacant without one or more prisoners، and even women،
children and the elderly are not spared from these arrests.
The problem of the study was to identify the role of public relations in the Ministry
of Detainees and Ex-Prisoners Affairs in educating the Palestinian public about the
issue of prisoners، the nature of this role and the means used to bring support and
solidarity with this important and sensitive issue through the applied study on the
employee
Witnessing the global arena many changes in the political, economic, social, scientific and technological have left their mark on the world as a whole, these changes require necessarily Advancement of the profession of auditing, and improve their performance, especially after the mixer skepticism the health of approach and the method followed by a check in the major audit firms global view as for the external audit of an active role in providing services to members of the community in various sectors, were to be provide these services to the highest level of quality.To ensure the quality of the audit process to be a proper planning is based on a scientific basis to be the substrate a strong underlying different audit works, and if planni
... Show MoreThis work is devoted to a comparative study of the phenomenon of enantiosemy in Russian and Arabic.Everyone knows the term antonyms - words of the same part of speech, opposite in meaning, such as: Day and night, white and black, truth and lies. But in Russian, Arabic and other languages there is an interesting phenomenon, which consists in the fact that one word has two opposite meanings. Such a phenomenon in linguistics is called enantiosemy (from the Greek words enantios - "opposite" and sema - "sign")