Abstract. This paper develops an optimal planning tool for VAR devices in the presence of a doubly fed induction generator (DFIG) based wind farm. The probabilistic wind power output associated with the capability curve of DFIG wind generator has been incorporated in the proposed formulation in order to examine its effect on the new VAR devices investment cost and compare the results with the current practice of the regulated power factor range of 0.95 leading and 0.95 lagging. The proposed method is stated as an optimization problem so that the objective function is to simultaneously minimize the sum of the annual investment cost of the new VAR devices as well as the annual expected energy loss cost. The objective function is achieved while simultaneously satisfying the investment constraints of the new VAR devices and several operating constraints including the effect of the wind park active power output and its associated VAR capability limits as well as the voltage security limits to enhance power system voltage stability.

Abstract . Information security has many aspects such as authentication, privacy, integrity and non-repudiation. This paper studies implementation of information security through cryptography and steganography. Cryptography can be loosely defined as the scramblingof data so that only an intended authorized user can unscramble it. Cryptography allows secure transfer of information over space (transmission over a communication channel) or over time (storage within a computer memory). Steganography is the related concept of hiding some piece of information within another piece of information (possibly of another type), such that the hidden information would be accessibly only to some intended authorized users. This paper offers a tutorial overview of cryptography and steganography from the perspective of a multi-key multi-stage software package (named EDSP forEncryption Decryption Software Package). This package serves as a pedagogical aid accompanying this current tutorial, though it is, admittedly, neither highly advanced nor particularly novel. It employs a one-time pad technique, wherein a key is used only once. The EDSPcombines a multitude of strong cryptographic algorithms, secret (symmetric) key ones together with public (asymmetric) key ones including the well-known RSA and El-Gamal algorithms, whose cryptanalyses show their relative unbreakability in front of strong attacks. Depending on the number of algorithms used, low, medium and high levels of security are achieved. Several random keys are generated and used only once through any encryption or decryption process. Depending on the size of message being encrypted, these keys are used through several schemes which are determined by the user. The package supports Arabic and English texts and can be enhanced toinclude more languages. It can be used with a variety of platforms with no specific hardware required. The package has a built-in capability of converting images into text and vice -verse, a key step in utilizing its cryptographic features for steganographic purposes. The steganography method is basically applied in the EDSP through converting any image into a text file or vice versa. However, hiding a secret image into another image is also performed and provided in the package. The paper briefly overviews the mathematics of pertinent operations, describes the capabilities of the developed package, and demonstrates its usefulness via illustrative examples. As an offshoot, the paper highlights contributions of the Arabs (during the glorious Islamic era) tocryptography, in general, and to cryptanalysis, in particular.

Abstract. The effects of surface polishing on the thermoelectric properties of InSb crystals have been studied. For this purpose, we grew high -quality InSb crystals. This crystal has the real surface and we call it “as prepared”. Also, a cleaned surface was obtained by polishing processes. A detailed work for comparing the measured thermoelectric in the pre-mentioned two cases was done. This included the study of the crystals by means of X-ray diffraction and the scanning electron microscopy images (SEM). The goal is to find out the influence of the surface treatment on the values of thermoelectric power (α). This was done over a wide range of temperatures (200-500K). Unique-results were obtained for the first time first time, and were represented using useful histograms.

Abstract. Eight samples were prepared according to the concentration of Ba-content (0, 10, 20, 30, 40, 55, 60 and 70 %). In the present research, full structural Investigations for of the [(PbxBa1-x) 0.81La0.125] TiO3ceramic compounds were accomplished using x-ray diffraction technique. The results extracted includes: the lattice parameters, the grain size and the percentage of crystallinity % of the compound. The investigation of the structural properties of this compound is useful for studying the dielectric and related properties such as the piezoelectric applications. Among the unique results found in the present investigation, we found that above 40 % of Ba, the compound is no longer tetragonal but it is converted into the cubic system (structural transformation).