# ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING

Online ISSN: 1319-8025
Publications
Conference Paper
In this study a broadcast routing algorithm has been developed for a faulty hypercube parallel processing system using cube algebra. Without any restriction to the number of the faulty nodes, the routing from the source node to the destination node is implemented minimally. The developed routing algorithm has been visually simulated via the prepared data routing simulator program. It has been observed that this algorithm can be applied to various routing problems

Conference Paper
A novel approach for an efficient network-on-chip using a modified Fat Tree is presented. Contention is eliminated and latency is reduced through an improved topology and router architecture. The adopted topology increases performance without a substantial increase in the routing cost. This is achieved by using an improved buffer-less, paremeterizable router architecture. The proposed router architecture is simple to implement yet can achieve the required packet collision avoidance. Simulation results that show the level of performance achieved by both the topology and the router architecture are presented. A throughput of more than 90% is achieved way above the 40-50% usually seen in other networks on chips.

Conference Paper
In this paper, an image restoration algorithm is proposed to identify nonlinear and noncausal blur function using artificial neural networks. Image and degradation processes include both linear and nonlinear phenomena. The proposed neural network model combines an adaptive auto-associative network with a random Gaussian process, is used to restore the blurred image and blur function, simultaneously. The noisy and blurred images are modeled as nonlinear continuous associative networks, whereas autoassociative part determines the image model coefficients and the hetero-associative part determines the blur function of the image degradation process. The self-organization like structure of the proposed neural network provides the potential solution of the blind image restoration problem. The estimation and restoration are implemented by using an iterative gradient based algorithm to minimize the error function.

Conference Paper
Quantum state swapping is required for long-distance quantum communication. Quantum state swapping protocols are based on the quantum controlled-NOT (CNOT) or similar quantum logic operations, which are very difficult to implement experimentally. Here we present a feasible scheme for the implementation of Quantum state swapping based on planar lightwave circuit (PLC) implementation of quantum CNOT gate. This quantum gate is realized by using Mach-Zehnder interferometer. By using planar lightwave circuit in implementation, the width of waveguides and the length of CNOT gate were obtained 12 micron and 2.8 cm respectively.

Conference Paper
This paper presents an on-line testing and diagnosis approach of microcontroller. The proposed approach has been achieved through both fault masking and fault diagnosis algorithms. Concurrent testing technique through using triple modular redundancy (TMR) is required to mask the operational faults and specially tolerate the transient faults. For permanent faults and in parallel with TMR, an on-line and non-concurrent fault detection and diagnostic technique is used to locate the faulty elements. The fault detection and diagnostic technique uses a set of assembly programs that test the entire microcontroller instruction-sets called macros. The macros are able to excite all of the microcontroller functions. A macro is associated to each machine-level instruction; and composed of a few instructions, aimed at activating the target instruction with some operand values representing the macro parameters and propagates the results of its execution to an observable memory positions. A Simulation study has been done using Xilinx Foundation tool, VHDL, and an FPGA Vertix chip.

Conference Paper
This paper presents a multiobjective differential evolution (MODE) based approach to solve the optimal power flow (OPF) problem. OPF problem has been treated as a true multiobjective constrained optimization problem. Different objective functions and different operational constraints have been considered in the problem formulation. A clustering algorithm is applied to manage the size of the Pareto set. Also, an algorithm based on fuzzy set theory is used to extract the best compromise solution. Simulation results on IEEE-30 bus test system show the effectiveness of the proposed approach in solving true multi-objective OPF and also finding well distributed Pareto solutions.

Conference Paper
An insensitive current mode versatile first order filter section with single input and multiple outputs is realized. The realization uses two multi outputs current conveyors, only one grounded resistor and one grounded capacitor. The realized current mode section provides low-pass, high-pass and all-pass responses at different outputs without any component matching constraint. The all-pass section is then cascaded with the current mode non-inverting integrator to realize a current mode multiphase sinusoidal oscillator. Thus the realized current mode oscillator provides eight phase sinusoidal outputs with equal magnitudes. The current mode outputs are loaded with same valued resistive load to achieve the eight phase voltage mode sinusoidal outputs with equal magnitudes. All the realization were designed and simulated using PSPICE. The simulation results thus obtained, verify the theory.

Article
Various theoretical models have been applied to evaluate the sound velocity values at 298.15 K for the ternary system of galactose with aqueous amylase and compared with experimental values. The validity of Nomoto (NR), Van Deal-Vangeal (IMR), Impedance dependence relation (IDR), Collision factor theory (CFT) and Nutsch-Kuhnkies (NK) methods is checked and a comparative study of these models is made. The non-ideal behavior of the systems is explained in terms of molecular interactions of the constituents of the mixture. KeywordsUltrasonic velocity–Galactose– α-Amylase–Theoretical models

Article
This paper tackles the problem of payload uncertainties through polytopic system formulation and robust controller design for a 2DOF parallel manipulator. Typically, such platforms are used as a base for different payloads, e.g. satellite antenna and camera in oceangoing crafts. Traditionally, these kinds of manipulators are modeled through a time varying nonlinear model, thus providing the rationale for a nonlinear or adaptive controller. Uncertainties due to load variations present a significant challenge for robust control design. In this paper, the authors have proposed a novel and practical approach to solve the variant payload dilemma for the stabilized platform. The novelty lies in extracting different linear models with distinct load conditions using the system identification method and quantifying them into a convex hull to formulate a polytopic system. A regulator is then designed by mixed H 2/H ∞ synthesis with pole-placement constraints in a linear matrix inequality (LMI) framework to compensate output disturbances. The results are compared with a Riccati-based H ∞ loop shaping controller. It is shown through simulations and experiments that an LMI design is a better choice for achieving robustness as well as performance. The hallmark of this work is the successful testing of the control strategy on a stabilized platform with heavy asymmetric satellite antenna to reject the tides’ effect in a deep, turbulent sea.

Article
Chromium compounds have received considerable attention because they have been used extensively in such industrial applications as electro-plating, steelmaking, tanning of leather goods, and as corrosion inhibitors. The use of flat sheet supported liquid membranes (FSSLMs) to remove metals from wastewaters has been actively undertaken by both the scientific and industrial communities. The present work deals with carrier-facilitated membrane transport of Cr(VI) from acidic media across a FSSLM using the organic extractant reagent Alamine 336. The efficiency of the membrane transport was optimized as a function of pH, diluent type, strip phase (NaOH) concentration, feed and strip phase mixing speed, extractant type and concentration, and support type. Various initial feed phase Cr(VI) concentrations were studied under the optimum conditions. At a 2,000ppm optimum feed phase concentration, the FSSLM showed no significant loss in permeability and retained the same transport ability over 49 h. Under that condition, the extraction of Cr(VI) was found to be >99% and the mass flux and permeation coefficient were calculated using related equations as 7.35× 10−6 kg m−2 s and 7.88× 10−6 m s−1, respectively. KeywordsCr(VI) extraction–Flat sheet supported liquid membrane (FSSLM)–Alamine 336–Tertiary amine extractants–Facilitated mass transport

Article
The aim of this study was to obtain a description of the neutral lutetium spectrum. We calculated the radiative parameters (wavelengths, weighted oscillator strengths and transition probabilities) for electric dipole (E1) transitions for some excited levels in neutral lutetium (Lu I, Z = 71). Two configuration interaction methods were used: the multiconfiguration Hartree–Fock method developed by Fischer within the Breit-Pauli relativistic framework (MCHF + BP), and Cowan’s relativistic Hartree–Fock (HFR) method. Results obtained have been compared with each other and with other works. A discussion of these calculations for Lu I in this study has also been in view of the MCHF + BP and HFR methods. KeywordsRelativistic correction–Wavelength–Oscillator strength–Transition probability

Article
The aim of this study was to compare the efficacy of three ASTM saturation techniques for measuring the water absorption of concrete. The water absorption of two ordinary concretes was determined based on the cold water, boiling water and vacuum saturation techniques. The concretes were produced with water to cement (w/c) ratios of 0.50 and 0.60 and tested at 7 and 28 days. The vacuum saturation was more effective than the cold water and boiling water saturation methods. The vacuum saturation technique produced up to 13.1% more water absorption than the boiling water saturation method and up to 20.2% more water absorption than the cold water saturation method. Thus the present study suggests that the vacuum saturation technique is more efficient than both cold water and boiling water saturation methods to measure the water absorption of concrete. KeywordsConcrete–Mixture proportions–Saturation techniques–Water absorption

Article
Chlorins are potential photosensitizers for photodynamic therapy because of their intense absorption in the red spectral region. In this study, the effect of pH on the absorption and fluorescence of Sn(IV) chlorin e6 dichloride trisodium salt was investigated. Absorption, fluorescence emission and fluorescence excitation spectra of the photosensitizer were recorded at different pH values in an analytical buffer solution with and without fetal bovine serum (FBS). In the neat buffer solution, changing the pH resulted in small shifts in both absorption and emission spectra. The shape of the excitation spectra also changed slightly, with shoulders almost vanishing below pH5. Also, a pronounced reduction of the fluorescence intensity was observed upon acidification. The fluorescence intensity gradually decreased as the concentration of FBS was increased without shifting fluorescence maxima. The absorbance of the photosensitizer in different solvents was recorded and revealed that Sn(IV) chlorin e6 is highly soluble in polar solvents. KeywordsSn(IV) chlorin e6–Titration curve–Acidification–Fluorescence–Absorption–Emission

Article
A new method was developed for the determination of trifluoperazine hydrochloride (TFPH) at trace levels in pharmaceuticals. This method involved formation of a TFPH-Pt(IV) complex at a specific pH, and extraction of this complex into an organic solvent. Flame atomic absorption spectrometry was used to measure the absorbance of platinum in the complex, and indirectly determine the concentration of TFPH. Under the optimized conditions, the linear dynamic range, detection limit, relative standard deviation (n=5), and the recoveries of the standard addition method were 2−60μg mL−1, 0.085μg mL−1, 1.58−2.03, and 102.24 ± 0.43, respectively. The proposed method was applied to the determination of TFPH in the drug Stelazine (5 mg of TFPH per tablet) by both direct and standard addition procedures and gave results of 4.89 and 4.88 mg of TFPH per tablet. This method was compared statistically with the determination of TFPH by UV–Vis spectroscopy, and the difference in the precision from these methods was insignificant at the 95% confidence level. KeywordsTrifluoperazine hydrochloride–Platinum(IV)–Stelazine–Atomic absorption spectroscopy–Indirect method

Article
Provisioning of quality of service (QoS) is a key issue in visible light communication (VLC) system as well as in other wireless communication systems. Due to the fact that QoS requirements are not as strict for all traffic types, more calls of higher priority traffic classes can be accommodated by blocking some more calls of lower priority traffic classes. Diverse types of high data rate traffic are supported by existing wireless communication systems while the resource is limited. Hence, priority based resource allocation can ensure the service quality for the calls of important traffic class. The fixed guard channels to prioritize any class of calls always reduce the channel utilization. In this paper we propose a priority based dynamic channel reservation scheme for higher priority calls that does not reduce the channel utilization significantly. The number of reserved channels for each of the individual traffic classes is calculated using real-time observation of the call arrival rates of all the traffic classes. The features of the scheme allow reduction of the call blocking probability of higher priority calls along with the increase of the channel utilization. The proposed Markov Chain model is expected to be very much effective for the queuing analysis especially for the priority scheme of any number of traffic classes. The numerical results show that the proposed scheme is able to attain reasonable call blocking probability of higher priority calls without sacrificing channel utilization.

Article
Bis(dibutyldithiocarbamato)metal complexes of cadmium and zinc were synthesized as precursors for growth of thin films of cadmium sulfide (CdS) and zinc sulfide (ZnS) by aerosol-assisted chemical vapor deposition on glass substrates. The decomposition of the precursor complexes was observed by thermogravimetric analysis, and it took place at 350–450°C with toluene used as the solvent. The CdS and ZnS films were analyzed by X-ray powder diffraction, scanning electron microscopy and energy-dispersive X-ray analysis. The preferred orientation of the crystallites within the films changed with respect to the deposition temperature. The scanning electron microscopy and energy-dispersive X-ray analysis results showed the uniform distribution of CdS and ZnS in the films, which makes them useful photoconducting materials on a structured surface. KeywordsCadmium sulfide–Zinc sulfide–Photoconductors–Aerosol-assisted chemical vapor deposition

Article
In this work, computer-aided finite element analysis to determine conditions for flashless cold forging of a connecting rod is presented. The workpiece specifications were calculated by developing mathematical relations between the volumes of the die cavity and workpiece. The three dimensional FE simulation was made using DEFORM-F3 V 6.0 and geometrical modeling of the die and workpiece was performed with SOLIDWORKS 2007 4.0. The workpiece modeled was of AISI 1045 steel and the die material was die steel (AISI D2). The aspect ratios for the bigger eye, smaller eye and column of the connecting rod were optimized to obtain the minimum flash volume without underfilling. Three workpiece geometries were modeled: cylindrical, pre-form 1 (dumbbell shape with fillet) and pre-form 2 (dumbbell shape without fillet). Pre-form 2 was found to be the optimum workpiece to obtain flashless forging without underfilling, while minimizing the material volume and forging load. KeywordsCold forging–Flashless forging–Underfilling–Plastic deformation–Optimization–Connecting rod

Article
Preserving forests and their value to us is indispensable to human life. When making forest preservation plans and managing forests efficiently, it is necessary to use three dimensional (3D) models of the forest regions. Apart from the traditional and photogrammetric methods used for producing these maps, the LIght Detection and Ranging (LIDAR) measurement technique with its various advantages has been used in recent years. This paper explains the principle of the operation of the LIDAR measurement system and discusses the determination of digital elevation models (DEM) of forest areas and their usage in 3D models. This test study aims to convert the scattered distributed 3D datasets obtained from airborne LIDAR technology to a digital elevation model with a regular grid format. One of the most significant aspects of this process, the interpolation method, which affects the quality of the final product when generating the digital elevation model, is examined with respect to data density and distribution, grid size interval and terrain type. KeywordsLIDAR–Three dimensional modeling–Forestlands–Digital elevation model–Interpolation methods

Article
Motivated by the study of von Neumann regular skew groups as carried out by Alfaro, Ara and del Rio in 1995 we investigate regular and biregular Hopf module algebras. If $A$ is an algebra with an action by an affine Hopf algebra $H$, then any $H$-stable left ideal of $A$ is a direct summand if and only if $A^H$ is regular and the invariance functor $(-)^H$ induces an equivalence of $A^H$-Mod to the Wisbauer category of $A$ as $A# H$-module. Analogously we show a similar statement for the biregularity of $A$ relative to $H$ where $A^H$ is replaced by $R=Z(A)\cap A^H$ using the module theory of $A$ as a module over $A\otimes A^{op} \bowtie H$ the envelopping Hopf algebroid of $A$ and $H$. We show that every two-sided $H$-stable ideal of $A$ is generated by a central $H$-invariant idempotent if and only if $R$ is regular and $A_m$ is $H$-simple for all maximal ideals $m$ of $R$. Further sufficient conditions are given for $A# H$ and $A^H$ to be regular.

Article
We show that the equivalence between several possible characterizations of Frobenius algebras, and of symmetric Frobenius algebras, carries over from the category of vector spaces to more general monoidal categories. For Frobenius algebras, the appropriate setting is the one of rigid monoidal categories, and for symmetric Frobenius algebras it is the one of sovereign monoidal categories. We also discuss some properties of Nakayama automorphisms.

Article
The various canonical subcategories of the category Hopf R of Hopf algebras over a commutative ring R, like those of (co)commutative Hopf algebras or Hopf algebras whose antipode is bijective or of order 2, are shown to be locally presentable categories and reflective and coreflective in their respective supercategories. The reflectivity results provided only hold for commutative von Neumann regular rings, while most of the coreflectivity results are valid over any ring. As a consequence one gets existence of free commutative Hopf algebras over coalgebras and cofree cocommutative Hopf algebras over algebras. KeywordsCommutative and cocommutative Hopf algebras–Bijective antipode–Reflections and coreflections

Article
The notion of crossed product with a coquasi-Hopf algebra H is introduced and studied. The result of such a crossed product is an algebra in the monoidal category of right H-comodules. We give necessary and sufficient conditions for two crossed products to be equivalent. Then, two structure theorems for coquasi-Hopf modules are given. First, these are relative Hopf modules over the crossed product. Second, the category of coquasi-Hopf modules is trivial, namely equivalent to the category of modules over the starting associative algebra. In deep connection with the crossed product is the notion of a cleft extension over a coquasi-Hopf algebra, introduced by the author in a previous paper. A Morita context of Hom spaces is constructed in order to explain these extensions, which are shown to be equivalent with crossed product with invertible cocycle.

Article
By using cocycle deformation, we construct a certain class of Hopf algebras, containing the quantized enveloping algebras and their analogues, from what we call pre-Nichols algebras. Our construction generalizes in some sense the known construction by (generalized) quantum doubles, but unlike in the known situation, it saves us from difficulties in checking complicated defining relations.

Article
In this paper, we establish the Composition-Diamond lemma for free differential algebras. As applications, we give Groebner-Shirshov bases for free Lie-differential algebra and free commutative-differential algebra, respectively.

Article
In the last decennia two generalizations of the Hopf algebra of symmetric functions have appeared and shown themselves important, the Hopf algebra of noncommutative symmetric functions NSymm and the Hopf algebra of quasisymmetric functions QSymm. It has also become clear that it is important to understand the noncommutative versions of such important structures as Symm the Hopf algebra of symmetric functions. Not least because the right noncommmutative versions are often more beautiful than the commutaive ones (not all cluttered up with counting coefficients). NSymm and QSymm are not truly the full noncommutative generalizations. One is maximally noncommutative but cocommutative, the other is maximally non cocommutative but commutative. There is a common, selfdual generalization, the Hopf algebra of permutations of Malvenuto, Poirier, and Reutenauer (MPR). This one is, I feel, best understood as a Hopf algebra of endomorphisms. In any case, this point of view suggests vast generalizations leading to the Hopf algebras of endomorphisms and word Hopf algebras with which this paper is concerned. This point of view also sheds light on the somewhat mysterious formulas of MPR and on the question where all the extra structure (such as autoduality) comes from. The paper concludes with a few sections on the structure of MPR and the question of algebra retractions of the natural inclusion of Hopf algebras of NSymm into MPR and section of the naural projection of MPR onto QSymm.

Article
Let $(A,\Delta)$ be a multiplier Hopf algebra. In general, the underlying algebra $A$ need not have an identity and the coproduct $\Delta$ does not map $A$ into $A\otimes A$ but rather into its multiplier algebra $M(A\otimes A)$. In this paper, we study {\it some tools} that are frequently used when dealing with such multiplier Hopf algebras and that are typical for working with algebras without identity in this context. The {\it basic ingredient} is a unital left $A$-module $X$. And the basic construction is that of extending the module by looking at linear maps $\rho:A\to X$ satisfying $\rho(aa')=a\rho(a')$ where $a,a'\in A$. We write the module action as multiplication. Of course, when $x\in X$, and when $\rho(a)=ax$, we get such a linear map. And if $A$ has an identity, all linear maps $\rho$ have this form for $x=\rho(1)$. However, the point is that in the case of a non-unital algebra, the space of such maps is in general strictly bigger than $X$ itself. We get an {\it extended module}, denoted by $\bar X$ (for reasons that will be explained in the paper). We study all sorts of more complicated situations where such extended modules occur and we illustrate all of this with {\it several examples}, from very simple ones to more complex ones where iterated extensions come into play. We refer to cases that appear in the literature. We use this basic idea of extending modules to explain, in a more rigorous way, the so-called {\it covering technique}, which is needed when using {\it Sweedler notations} for coproducts and coactions. Again, we give many examples and refer to the existing literature where this technique is applied.

Article
This work is devoted to study new bialgebra structures related to 2-associative algebras. A 2-associative algebra is a vector space equipped with two associative multiplications. We discuss the notions of 2-associative bialgebras, 2-bialgebras and 2-2-bialgebras. The first structure was revealed by J.-L. Loday and M. Ronco in an analogue of a Cartier-Milnor-Moore theorem, the second was suggested by Loday and the third is a variation of the second one. The main results of this paper are the construction of 2-associative bialgebras, 2-bialgebras and 2-2-bialgebras starting from an associative algebra and the classification of these structures in low dimensions.

Article
This study was conducted in northeast Algeria along the Tunisian border. The principal goal of this study was to characterize the groundwater quality of the Mafragh Watershed and the space variation. Hydrochemical analyses of salinity (Cl, SO4), organic pollution (BOD5, dissolved oxygen DO) and dissolved metals (Fe, Cu, Zn) were conducted at 22 stations located in the proximity of the Kebir East and Bounamoussa rivers, which constitute the Mafragh Watershed. Sampling was conducted during the end of the high-water period (May 2007). This study revealed a DO content of 5mg/l, as well as high BOD5 (40mg/l), Cl (400mg/l) and SO4 (250mg/l) values. Conversely, metals did not show high concentrations, with Fe ranging from 0.01 to 0.032mg/l, and Cu and Zn being near the detection limit. KeywordsWatershed–Salinity–Organic pollution–Metal pollution

Article
A direct current plasma enhanced chemical vapor deposition (DC PECVD) apparatus was designed and constructed to synthesize high purity vertically well-aligned carbon nanotubes (VACNTs) at relatively low temperatures. The effect of C2H2 concentration and plasma current on CNT growth was investigated. The DC PECVD synthesis of CNTs consisted of two steps: (1) reduction with gaseous H2 and NH3 to form catalyst nanoparticles, and (2) subsequent CNT growth in the presence of gaseous H2 and C2H2. High-resolution transmission electron microscopy images confirmed the presence of multi-walled carbon nanotubes (MWCNTs). Their graphitic structure was then confirmed by Raman spectroscopy. Scanning electron microscopy (SEM) results illustrated the relationship between the plasma, C2H2 concentration and CNT growth. Deviation of acetylene flow rate from an optimal rate led to deterioration of CNT growth. Comparing SEM images of CNTs grown with and without plasma showed that plasma had an important role in VACNT formation. KeywordsCarbon nanotubes–PECVD–Vertical-aligned growth–MOSFET

Article
Geoelectrical measurements using a vertical electrical sounding method were conducted in the southern Amman district, central Jordan. The objectives of the study were to identify formations that may present freshwater aquifers, and to estimate the relationship between groundwater resources and geological structures. Data collected at 23 locations were first interpreted with curve-matching techniques, using theoretically calculated master curves. The initial earth models were double-checked and reinterpreted using a one-dimensional inversion program to obtain the final subsurface stratigraphic units, including the water-bearing aquifer. The geoelectrical cross section showed that the subsurface consists of five geoelectric units. The aquifer is underlain by the last unit comprised of limestone (of Campanian age) of the Balqa Group deposits. The depth of the top of the Campanian limestone (B2/A7 aquifer) ranges between 180 and 290m. The resistivity of the aquifer varies between 50 and 200ohm m, indicating the existence of good quality water. KeywordsGeoelectrical measurements–Vertical electrical sounding–Groundwater aquifer–Central Jordan

Article
In this paper, two kinds of frequency–amplitude formulation are used to solve the generalized conservative nonlinear equation in the form of u¢¢+u+u2n-1Ö{1+e2u4m}=0{{u}^{\prime\prime}+u+u^{2n-1}\sqrt{1+\varepsilon^{2}u^{4m}}=0} for any arbitrary power of n and m. This equation is a general form of plasma physics equations and the Duffing equation. A frequency analysis is carried out and the relationship between the angular frequency and the initial amplitude is obtained in closed analytical form. This equation is analyzed in three cases: as a plasma physics equation, as a higher order Duffing equation and as an equation with irrational restoring force. Comparison with the exact integration method is also made, revealing that the present method leads to accurate solutions. KeywordsConservative nonlinear oscillators–Frequency–amplitude formulation–Plasma physics–Duffing equation

Article
In this article, we consider some subordination and superordination results involving the Dziok–Srivastava linear operator and the Srivastava–Owa fractional integral operator for certain normalized analytic functions in the open unit disk. Moreover, we discuss the existence of univalent solutions for fractional differential equations involving the Dziok–Srivastava linear operators. Some well-known results are introduced as special cases. KeywordsDziok–Srivastava linear operator–Srivastava–Owa fractional integral operator–Univalent solution–Subordination–Superordination

Article
In this study, we have investigated the application of an external RC shear wall as a method of improving the performance of reinforced concrete (RC) frames in an earthquake. We produced a series of eight RC frames, each of which was modeled at a 1/3 scale with two floors and two spans. These frames were of the same size and had design and construction deficiencies commonly encountered in the RC buildings in Turkey. We tested four of the eight frames without any strengthening, under reversed cyclic lateral loadings resembling earthquake loads. The remaining four frames we tested under the same conditions after strengthening them with RC external shear walls. We arranged the axial force loads applied to the columns of the test models in two different ways to result in tensile and compression failure. The test results were analyzed on the basis of a comparison using static push over analysis. The results of the experimental tests and analytical studies showed that the RC external shear wall improved the seismic character of the existing RC frame as much as RC infill walls, therefore this method can be used as an alternative strengthening method. Also, the method provides effective, practical and economical strengthening that minimizes the need for additional works and does not restrict the use of the RC building. KeywordsReinforced-concrete frame–Strengthening–External shear wall–Tensile and compression failures–Earthquake effect–Analytical and experimental method

Article
We consider the possible discovery potential for single production of charged heavy leptons via anomalous interactions at the envisaged Compact Linear Collider (CLIC) by taking into account initial state radiation (ISR) and beamstrahlung effects. We calculate the production cross sections and decay widths of charged heavy leptons in the context of anomalous interactions at center of mass energies $\sqrt{s}=1$ and 3 TeV. The signal and corresponding backgrounds are studied in detail for the mass range 300-1900 GeV.

Article
Tire failures, including catastrophic tread separation and blowouts, are common events that lead to serious road accidents in Saudi Arabia. In this paper, a field investigation of eight different brands of tires in Saudi Arabia was performed to understand the reasons for tire failure. Their performances were monitored in the field for a period of 10 months and then subjected to laboratory tests to investigate the effect of field conditions on the mechanical properties of the tires at the end of the performance period. The selected tires were chosen based on a previous survey conducted to determine tires which failed commonly and rarely the best four and the worst four brands in terms of failure rate were selected for this study. Field performance was measured via the strength and ductility of the tire materials, in addition to the failure events reported during the service period. Laboratory tests were performed on used and new tires to determine the effect of in-service conditions on tire properties. The laboratory tests included strength, peeling, tensile, elongation, bead unseating, endurance, and high-speed performance tests. With regard to the new tires, all the tested brands passed the internationally adopted tire quality control tests. However, the results indicated some differences between the frequently and infrequently failed tires in terms of some physical properties and the percentage of failed tires during field use. KeywordsTire failure–Tire ductility–Bead unseating–Strength test–Tire accidents–Tire performance

Article
The purpose of this paper is to revisit the infinite Lie group theoretical framework of hydrodynamics developped by V. Arnold in 1966. First of all, we extend this approach from the Lie pseudogroup of volume preserving transformations to an arbitrary Lie pseudogroup. Then we prove that, contrary to what could be believed from the work of Arnold which is of a purely analytical nature, the same results can be obtained from a purely formal point of view. Finally, we provide the analogue for both the so-called "body" and "space" dynamical equations. We conclude by showing that even this new approach can be superseded by dynamics on Lie groupoids, along ideas pioneered by the brothers E. and F. Cosserat or H. Weyl at the beginning of the last century, on the condition to change the underlying philosophy.

Article
Combinatorial optimization problems are generally NP hard problems that require large run-times when solved using iterative heuristics. Parallelization using distributed or shared memory computing clusters thus becomes a natural choice to speed up the execution times of such problems. In this paper, several parallel schemes based on an asynchronous multiple-Markov-chain (AMMC) model are explored to parallelize simulated annealing (SA), used for solving a multiobjective VLSI cell placement problem. The different parallel schemes are investigated based on the speedups and solution qualities achieved on an inexpensive cluster of workstations. The problem requires the optimization of conflicting objectives (interconnect wire-length, power dissipation, and timing performance), and fuzzy logic is used to integrate the costs of these objectives. The goal is to develop effective AMMC-based parallel SA schemes to achieve near linear speedups while maintaining or achieving higher solution qualities in less time and to analyze these parallel schemes against the common critical performance factors. KeywordsAsynchronous MMC–Parallel SA schemes–Multiobjective cell placement–Cluster-of-workstations

Article
In this paper, we discuss some recent results on graphs attached to rings. In particular, we deal with comaximal graphs, unit graphs, and total graphs. We then define the notion of cototal graph and, using this graph, we characterize the rings which are additively generated by their zero divisors. Finally, we glance at graphs attached to other algebraic structures. KeywordsChromatic index–Chromatic number–Clique number–Comaximal graph–Connectedness–Cototal graph–Counit graph–Diameter–Finite ring–Girth–Hamiltonian cycle–Hamiltonian graph–Planarity–Total graph–Unit element–Unit graph–Weakly perfect graph–Zero-divisor graph

Article
The search for techniques to improve software quality and achieve robust, reliable, and maintainable software is ongoing. Refactoring, an approach that improves the internal structure of software without affecting its external behavior, is one method that aims to achieve better quality. Refactoring to patterns is another. The goal of this paper is to investigate whether refactoring to patterns improves software quality. This is done empirically by examining the metric values of external quality attributes for different software systems before and after refactoring to patterns is applied. We found no consistent improvement trends in the software quality attributes. This is because each refactoring to patterns technique has a particular purpose and effect, and hence affects software quality attributes differently. KeywordsSoftware refactoring–Software metrics–Refactoring to patterns–Quality improvement–Empirical study

Article
Refactoring is the process of improving the design of existing code by changing its internal structure without affecting its external behavior. Refactoring tends to improve software quality by improving design, improving readability and reducing ‘bugs’. There are many different refactoring methods, each having a particular purpose and effect. Consequently, the effect of refactoring methods on software quality attributes may vary. Moreover, it is often unclear to software designers how to use refactoring methods to improve specific quality attributes. In this paper, we propose a classification of refactoring methods based on their measurable effect on software quality attributes. This, in turn, helps software designers choose appropriate refactoring methods that will improve the quality of their designs, based on the design objectives. It also enables them to predict the quality drift caused by using particular refactoring methods. KeywordsSoftware refactoring–Software metrics–Software quality attributes–Refactoring classification

Article
Let L(S){\mathcal{L}(S)} denote the set of lower bounds of a set S in partially ordered set T and let G + denote the positive cone of a partially ordered group G. We study directed groups G with the (pR) property: if x1,x2,¼,xn Î G+{x_{1},x_{2},\ldots,x_{n}\in G^{+}} such that L(x1,x2,¼,xn) ¹ L(0),{\mathcal{L}(x_{1},x_{2},\ldots,x_{n})\not=\mathcal{L}(0),} then there is a strictly positive element l≤ x i in G. Calling these groups pre-Riesz, we show that Conrad’s F-condition which was stated for lattice-ordered groups can still be stated for pre-Riesz groups and has similar effects modulo minor changes in definitions of basic elements and bases. As applications of our work we study integral domains whose groups of divisibility and groups of *-invertible *-ideals, for finite character star operations *, are pre-Riesz and pre-Riesz satisfying Conrad’s F-condition. KeywordsGroup of divisibility–F-condition–Pre-Riesz group–Homogeneous element–Basis–PSP domain

Article
Introducing the concept of basic displacement functions (BDFs), a new beam element is presented for the analysis of rotating tapered beams. BDFs are obtained using the energy method; i.e., the unit-load method. Following the basic principles of structural mechanics, it is shown that the shape functions and consequently the structural matrices can be derived in terms of BDFs. The method is a combination of flexibility and stiffness methods and is considered as the logical extension of the conventional finite element method. The method is employed for both static and free vibration analyses of different types of tapered beams, and the results compare well with those in the literature. Finally, the effects of the taper ratio, hub radius and rotating speed parameter on the natural frequencies and static deflection are investigated. The results obtained are satisfactory even for only a few elements. KeywordsBasic displacement functions–Shape functions–Non-prismatic rotating beam–Free vibration–Static analysis

Article
Recent experimental evidence has shown that face-centered-cubic materials that are not normally associated with deformation twinning will twin during moderate high-current pulsed electron beam (HCPEB) processing. In this paper, we present an experimental investigation of deformation twinning in pure multi-crystalline nickel exposed to HCPEB irradiation from a Nadezhda-2 HCPEB device. The samples, which were irradiated with various numbers of pulses, were examined. The formation of a large number of twin lamellae on the treated surface was observed in the regions without surface melting. Moreover, a large strain located at the twin lamellae deformation was found. Transmission electron microscope analysis revealed that the deformation twinning was indeed triggered during the HCPEB irradiation. This suggests that the very high stresses and superfast strain rates induced via the rapid heating and cooling caused by the HCPEB irradiation lead to deformation twinning in coarse-grained nickel. KeywordsHigh-current pulsed electron beams (HCPEB)–Pure nickel–Deformation–Twin

Article
We give a formal concept of (right) wide Morita context between two 0-cells in arbitrary bicategory. We then construct a new bicategory with the same 0-cells as the oldest one, and with 1-cells all these (right) wide Morita contexts. An application to the (right) Eilenberg-Moore bicategory of comonads associated to the bimodules bicategory is also given.

Article
For any k-coalgebra C it is shown that similar quasi-finite C-comodules have strongly equivalent coendomorphism coalgebras; (the converse is in general not true). As an application we give a general result about codepth two coalgebra homomorphisms. Also a notion of codepth two bicomodule is introduced. The last section applies similarity to an endomorphism ring theorem for quasi-Frobenius (QF) bimodules and then to finite depth ring extensions. For QF extensions, we establish that left and right depth two are equivalent notions as well as a converse endomorphism theorem, and characterize depth three in terms of separability and depth two.

Article
In this paper we study some bootstrap properties of normalized extreme generalized order statistics under the assumption of a nondegenerate limit. The inconsistency, weak consistency and strong consistency of bootstrapping normalized extreme generalized order statistics for an appropriate choice of re-sample size are investigated when the normalizing constants are either known or unknown. A simulation study is given as an illustrative numerical example to explain how the suggested procedure is a very efficient tool for modeling extremes. KeywordsWeak consistency–Strong consistency–Extreme generalized order statistics–Bootstrap–Monte Carlosimulation

Article
Turaev introduced the notions of group coalgebras, Hopf group coalgebras and quasitriangular Hopf group coalgebras. Virelizier studied algebraic properties of Hopf π-coalgebras. In this paper, we give the definitions of a (crossed) left H-π-modules over a (crossed) Hopf π-coalgebra H, and show that the categories of (crossed) left H-π-modules are both monoidal categories. Finally, we show that a family R={Ra, b Î Ha ÄHb}a, b Î p{R=\{R_{\alpha, \beta} \in H_{\alpha} \otimes H_\beta\}_{\alpha, \beta\in\pi}} of elements is a quasitriangular structure of a crossed Hopf π-coalgebra H if and only if the category of crossed left H-π-modules over H is a braided monoidal category with braiding defined by R. KeywordsCrossed left H-π-modules–Braided monoidal category

Article
We give the definition of a bundle over a simplicial set in a similar way to that in general bundle theory. We define certain transition functions, called compatible transition functions, for the given bundle, as well as so-called admissible trivializations. Conversely, we give the description of an associated bundle over the realization of the simplicial set and trivializations for a given set of transition functions. KeywordsSimplicial set–Realization–Bundle theory–Transition function

Article
Quantum principal bundles or principal comodule algebras are re-interpreted as principal bundles within a framework of Synthetic Noncommutative Differential Geometry. More specifically, the notion of a noncommutative principal bundle within a braided monoidal category is introduced and it is shown that a noncommutative principal bundle in the category opposite to the category of vector spaces is the same as a faithfully flat Hopf-Galois extension. Comment: 18 pages

Article
In this paper, motion equations for the synchro-drive robot Nomad 200 are solved by using Linde Buzo Gray (LBG) clustering neural networks. The trajectories of the Nomad 200 are assumed to be composed of straight line segments and curves. The structure of the curves is determined by only two parameters, turn angle and translational velocity in the curve. The curves of the trajectories are found by using artificial neural networks (ANN) and the LBG clustered ANN. In this study a clustering method is used to improve the learning and test the performance of the ANN. In general, the LBG algorithm is used in image processing as a quantizer. This is the first publication where the LBG algorithm is successfully used in clustering ANN data sets. Thus, the best training data set of the ANN is achieved and minimum error values are obtained. It is shown that LBG-ANN models are better than the classic ANN models. KeywordsMobile robot–Neural networks–Clustering–Linde Buzo Gray algorithm

Top-cited authors
• Thapar Institute of Engineering & Technology, Patiala
• International Islamic University Malaysia
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