Structural analysis of Arabic handwriting: segmentation and recognition

In this paper, a structural method of recognising Arabic handwritten characters is proposed. The major problem in cursive text recognition is the segmentation into characters or into representative strokes. When we segment the cursive portions of words, we take into account the contextual properties of the Arabic grammar and the junction segments connecting the characters to each other along the writing line. The problem of overlapping characters is resolved with a contour-following algorithm associated with the labelling of the detected contours. In the recognition phase, the characters are gathered into ten families of candidate characters with similar shapes. Then a heterarchical analysis follows that checks the pattern via goal-directed feedback control.     

Analysis of a loss-of-flow accident resulting from the primary pump shaft break transient of the NUR research reactor

ABSTRACT

This paper presents a combined experimental and numerical simulation approach to investigating safety issues related to postulated loss-of-flow accident (LOFA) cases, which are more likely to occur in the NUR Research Reactor (Algeria).

The transients investigated at nominal-power operating conditions are related to the loss of flow resulting from an instantaneous shaft break in the main cooling pump of the NUR reactor.

The investigations are based on hydrodynamic and thermal hydraulic experiments to assess the reactor cooling system’s behavior.

3D Monte Carlo neutron transport calculations were performed with the (MCNP) code to determine the resulting neutronic properties of the core. In the accident analysis, a model of the primary cooling system was applied via the RELAP5 code. The experimental data and RELAP5 predictions showed good agreement. Additionally, the LOFA due to the transient scenario of the pump shaft break was compared with the LOFA due to normal loss of the coolant pump power transient. The results obtained from the transient (LOFA) studies revealed that in both cases, the lower limit of the minimum critical heat flux ratio and minimum onset of flow instability ratio for NUR is satisfied with a sufficient margin.     

Modified PSO algorithm for multi-objective optimization of the cutting parameters

Economic profit of machining is essentially based on the optimal selection of cutting parameters. In this paper, a multi-objective particle swarm optimization approach is introduced to optimize the cutting parameters in turning processes: cutting speed, feed rate and cutting depth. The proposed model presents the problem in form of a multi-objective problem with production rate and used tool life objectives and has a set of constraints that represent the important limitations to be satisfied. To obtain the non dominated solutions and build the Pareto front graph, a modified dynamic neighborhood particle swarm optimization (DNPSO) technique is used. In addition, a fuzzy-based mechanism is employed to extract the best compromise solution. The results on an illustrative sample reveal the capabilities of the proposed DNPSO approach to generate well-distributed Pareto optimal solutions. Comparison with multi-objective deterministic approach (Min?CMax) shows the superiority of the proposed approach and confirms its potential for solving multi-objective problems.     

Hydrodynamic study involving a maxblend impeller with yield stress fluids

In the present study, the hydrodynamic characteristics of the Maxblend impeller have been investigated. A commercial CFD package (CFX 12.0) was used to solve the 3D hydrodynamics and to characterize the flow patterns at every point. A shear thinning fluid with yield stress was modeled in the laminar regime and transition regime. The study focused on the effect of fluid rheology, agitator speed, impeller clearance from the tank bottom and blade size on the fluid flow and power consumption. Predictions have been compared with literature data and a satisfactory agreement has been found.     

Search-based model transformation by example

Model transformation (MT) has become an important concern in software engineering. In addition to its role in model-driven development, it is useful in many other situations such as measurement, refactoring, and test-case generation. Roughly speaking, MT aims to derive a target model from a source model by following some rules or principles. So far, the contributions in MT have mostly relied on defining languages to express transformation rules. However, the task of defining, expressing, and maintaining these rules can be difficult, especially for proprietary and non-widely used formalisms. In some situations, companies have accumulated examples from past experiences. Our work starts from these observations to view the transformation problem as one to solve with fragmentary knowledge, i.e. with only examples of source-to-target MTs. Our approach has two main advantages: (1) it always proposes a transformation for a source model, even when rule induction is impossible or difficult to achieve; (2) it is independent from the source and target formalisms; aside from the examples, no extra information is needed. In this context, we propose an optimization-based approach that consists of finding in the examples combinations of transformation fragments that best cover the source model. To that end, we use two strategies based on two search-based algorithms: particle swarm optimization and simulated annealing. The results of validating our approach on industrial projects show that the obtained models are accurate.     

3D hydrodynamics involving multiple eccentric impellers in unbaffled cylindrical tank

In this paper, the numerical predictions of 3D hydrodynamics and power consumption in a vessel stirred by mul-tiple eccentrical y located impel ers are presented. The vessel is a flat-bottomed cylindrical one equipped with six-curved bladed impel ers. Aqueous solutions of xanthan gum are used, which have a shear thinning behavior with yield stress. The influence of several parameters on the mixing efficiency has been investigated, namely:the stirring rate, fluid rheology, impeller number and impeller clearance from the tank bottom. Our predicted results are compared with other experimental data and a satisfactory agreement is found.     

Fluorinated functionalized EDOT-based conducting films

Three ethylenedioxithiophene (EDOT) derivatives bearing either perfluoro- or ether perfluoro-alkyl chains were synthesized with the objective to prepare films with dry and chemically immobilized lubrication properties. The corresponding fluorinated PEDOT films were deposited on platinum surface by electropolymerization. Cyclic voltammetry (CV) and electrochemical quartz crystal microbalance (EQCM) analyses (both quartz resonant frequency and resonant admittance) of the growing steps are described. The electroactive behavior of the films versus their doping level was followed by electrochemical impedance spectroscopy (EIS) through equivalent circuit fitting procedure and compared to their CV responses. Hysteresis in fit parameters corresponding to capacity and film resistance between the forward and the backward scans are observed and discussed. Control of the chemical structures and charge effects on PEDOT chains are followed by an XPS analysis. From these analyses, it appears that the fluorinated side-arm does not alter both the growing and the electrical properties of the films in respect to the pristine PEDOT taken as reference.     

Empirical studies to assess the understandability of data warehouse schemas using structural metrics

Data warehouses are powerful tools for making better and faster decisions in organizations where information is an asset of primary importance. Due to the complexity of data warehouses, metrics and procedures are required to continuously assure their quality. This article describes an empirical study and a replication aimed at investigating the use of structural metrics as indicators of the understandability, and by extension, the cognitive complexity of data warehouse schemas. More specifically, a four-step analysis is conducted: (1) check if individually and collectively, the considered metrics can be correlated with schema understandability using classical statistical techniques, (2) evaluate whether understandability can be predicted by case similarity using the case-based reasoning technique, (3) determine, for each level of understandability, the subsets of metrics that are important by means of a classification technique, and assess, by means of a probabilistic technique, the degree of participation of each metric in the understandability prediction. The results obtained show that although a linear model is a good approximation of the relation between structure and understandability, the associated coefficients are not significant enough. Additionally, classification analyses reveal respectively that prediction can be achieved by considering structure similarity, that extracted classification rules can be used to estimate the magnitude of understandability, and that some metrics such as the number of fact tables have more impact than others.

Effect of natural pozzolana and polypropylene fibers on the performance of lime mortar for old buildings restoration

The main objective of this research is to elaborate a mortar based on lime (L), pozzolana (PZ) and polypropylene fibers (PP) to restore and renovate the stone constructions while maintaining their initial comfort. Unlike the new buildings, in rehabilitation, we have to deal with the existing ones. For this purpose, mortars samples from an old building, chosen as cases of study, were taken and chemically analyzed in order to reproduce their equivalent mortars. Three different mortars were made and studied. A lime based mortar (M1), lime-pozzolana based mortar (M2) and lime-pozzolana based mortar with polypropylene fibers (M3). In order to preserve the thermal comfort offered by the old building, the thermal conductivity and the mechanical proprieties were studied. The adhesion of each mortar was also tested on several support types (concrete, concrete block, brick and natural stone). Finally, the three studied mortars were applied on the facade of the chosen building. The results are satisfactory on both levels aesthetic and adhesion. The incorporation of polypropylene fibers was more promising regarding thermal comfort. Moreover, their use lightened the matrix and improved the tensile strength.     

A Concept Formation Based Approach to Object Identification in Procedural Code

Legacy software systems present a high level of entropy combined with imprecise documentation. This makes their maintenance more difficult, more time consuming, and costlier. In order to address these issues, many organizations have been migrating their legacy systems to emerging technologies. In this paper, we describe a computer-supported approach aimed at supporting the migration of procedural software systems to the object-oriented (OO) technology. Our approach is based on the automatic formation of concepts, and uses information extracted directly from code to identify objects. The approach tends, thus, to minimize the need for domain application experts.