Free-Space Optical (FSO) can provide high-speed communications when the effect of turbulence is not serious. However, Space-Time-Block-Code (STBC) is a good candidate to mitigate this seriousness. This paper proposes a hybrid of an Optical Code Division Multiple Access (OCDMA) and STBC in FSO communication for last mile solutions, where access to remote areas is complicated. The main weakness effecting a FSO link is the atmospheric turbulence. The feasibility of employing STBC in OCDMA is to mitigate these effects. The current work evaluates the Bit-Error-Rate (BER) performance of OCDMA operating under the scintillation effect, where this effect can be described by the gamma-gamma model. The most obvious finding to emerge from the analysis is that the BER can be enhanced by orders of magnitude for different numbers of users and different values of scintillation effects using a MIMO
Bending effects on the transmission of optical signal are investigated on a single mode
optical fiber (SMOF) of 10 m length, core radius of 5 μm and optical refractive index difference
0.003. The bending radii (R) were between 0.08 and 0.0015 m. A great decrease in the amplitude is
shown for radii below 0.01 m. Sudden break down occurs for radii less than 0.0015 m. Birefringence
(B) is difficult to measure for long fibers. Meanwhile, B was found by comparing with calibrated
fiber of the same properties but of length of 0.075 m. The results show an increase in propagation
constant (Δβ) and the decrease in beat length (Lb), and show that bending decreases the critical radius
of curvature (Rc) related to B. The chang
This research dealt with highlighting the images of marriage through the modern means of communication and the legal ruling for it. Dowry even be knotted on them; because they are then one of the parties to the contract and contracted in one contract, and this is prohibited by law and law and common sense.
It turns out that it is permissible to advertise marriage through the Internet in accordance with the rules and standards that preserve values and morals and safeguard dignity and chastity. The acts in Islamic law are vested with intentions. If intentions are true, then the act is true, and Internet marriage is what falls under this order.<
... Show MoreMeans of communication has a great impact on all fields of awareness including health awareness by increasing the knowledge of community about health and developing their abilities to improve human health and cultural awareness. According to the importance of health awareness for a community to develop their intellectual and physical integrity, the researcher has found that it is essential to know the role of means of communication as a source of information for many students being active and main segments to build their society intellectually, socially and economically.
The research has focused on the study of health awareness among students and their health knowledge derived from the means of communicat
... Show MoreThe research aims to build a communication apprehention scale for student (females) from preparatory schools .research sample included (400)students (females) were selected from the preparatory . to build a tool for the researchers are several steps , todetermine the meaning of communication apprehention and formulation of the items of the seale according to the linkert method .
paid recent developments in the information and communications technology and the accompanying developments in the global market to pay particular accounting information users to demand more sophistication in terms of corporate financial reporting systems, which led to the emergence of a new type of reporting (financial reporting in real time). where is the information and communications technology mainstay Nations for the development and progress, thanks to the development of technology that have made the transmission of information easily conducted and high speed to all who need it, communication is instantaneous and the flow of information via the internet dramatically exceeded the border temporal and spatial anywhere in the w
... Show MoreAbstract
The aim of the current research is to identify the level of administrative applications of expert systems in educational leadership departments in light of the systems approach. To achieve the objectives of the research, the descriptive-analytical and survey method was adopted. The results showed that the level of availability of the knowledge base for expert systems in educational leadership departments (as inputs) was low. The level of availability of resources and software for expert systems in educational leadership departments (as transformational processes) came to be low, as well as the level of availability of the user interface for expert systems in educational leadership departments (as outputs
... Show MoreVideo copyright protection is the most generally acknowledged method of preventing data piracy. This paper proposes a blind video copyright protection technique based on the Fast Walsh Hadamard Transform (FWHT), Discrete Wavelet Transform (DWT), and Arnold Map. The proposed method chooses only frames with maximum and minimum energy features to host the watermark. It also exploits the advantages of both the fast Walsh Hadamard transform (FWHT) and discrete wavelet transforms (DWT) for watermark embedding. The Arnold map encrypts watermarks before the embedding process and decrypts watermarks after extraction. The results show that the proposed method can achieve a fast embedding time, good transparency, and robustness against various
... Show MoreAbstract: The aim of this study was to identify the Distress Tolerance among the Employees in Media and Communication in Baghdad.and to identify the significance of the differences between sex ,scientific specialization ,age,and marital status. and the researcher used the Distrees Tolerance measure for Simon &Gahar 2005. The sample of the study consisted of(37)Employees.The Scale of Distrees Tolerance were used as the study tools after being checked for their Validity and Reliability. The research results indicated that employees have high scores on the scale of stress tolerance and that there are statistically significant differences between the age groups and between married and unmarried people a
... Show MoreZ-scan has been utilized for studying the non-linear properties and optical limiting behaviors of the dye Copper Phthalocyanine thin films. The refractive index is negative, which indicates a self-defocusing behavior and non-linear absorption coefficient (