Hot water defrosting of a horizontal flat plate cooling surfaceDégivrage par eau chaude d'une surface de refroidissement de plaque plane horizontale

Removal of frost from an jupward facing horizontal cooling plate at a subfreezing temperature using a hot water spray is studied experimentally. The variation of the frost layer with time is approximately linear. A simple analytical model predicts the trend of the frost thickness-time change.     

An FPGA implementation of a neural optimization of block truncation coding for image/video compression

This paper presents a Field Programmable Gate Array (FPGA) implementation for image/video compression using an improved block truncation coding (BTC) image compression technique. The improvement is achieved by employing a Hopfield neural network (HNN) to calculate a cost function upon which a block is classified as either a high- or a low-detail block. Accordingly, different blocks are coded with different bit rates and thus resulting in better compression ratios. The paper formulates the utilization of HNN within the BTC algorithm in such a way that a viable FPGA implementation is produced. The implementation exploits the inherent parallelism of the BTC/HNN algorithm to provide efficient algorithm-to-architecture mapping. The Xilinx VirtexE BTC implementation has shown to provide a processing speed of about 1.113 × 10⁶ of pixels per second with a compression ratio which varies between 1.25 and 2 bits/pixel, according to the image nature.     

A multi-level analysis of factors affecting software developers’ intention to reuse software assets: An empirical investigation

Reuse of software assets in application development has held promise but faced challenges. In addressing these challenges, research has focused on organizational- and project-level factors while neglecting grass-root level adoption of reusable assets. Our research investigated factors associated with individual software developers’ intention to reuse software assets and integrated them in TAM. Towards that end, 13 project managers were interviewed and 207 software developers were surveyed in India. Results revealed that the technological-level (infrastructure), and individual-level factors (reuse-related experience and self-efficacy) were major determinants. Implications are discussed.     

Evaluation of Augmented Reality for Rapid Assessment of Earthquake-Induced Building Damage

This paper discusses the feasibility of using augmented reality (AR) to evaluate earthquake-induced building damage. In the proposed approach, previously stored building information is superimposed onto a real structure in AR. Structural damage can then be quantified by measuring and interpreting key differences between the real and augmented views of the facility. Proof-of-concept experiments were performed in conjunction with large-scale cyclic shear wall tests. In these, CAD images of the walls were superimposed onto the wall specimens. Then, as the wall specimens were deformed under applied loading, the horizontal drifts between the walls and the augmented images were computed using two different techniques and compared with actual wall drifts. The obtained results highlight the potential of using AR for rapid damage detection and indicate that the accuracy of structural displacements measured using AR is a direct function of the accuracy with which augmented images can be registered with the real world. The limitations of the technology, considerations for field implementation, and the potential for other related applications of AR are also discussed.     

On consensus algorithms design for double integrator dynamics

This paper considers the consensus problem of double integrator multi-agent systems where: (i) each agent is subject to input saturations, and (ii) the velocity (second state) of each agent is not available for feedback. We present new consensus algorithms that handle simultaneously the above mentioned situations. Sufficient conditions are derived such that consensus algorithms developed for first- and second-order multi-agent systems in ideal situations can be used to account for input saturations and remove the requirement of velocity measurements. To illustrate the effectiveness of the proposed approach, we propose solutions to two different second-order consensus problems in the case where the input is saturated and the velocity states are not available for feedback and simulation results are provided in each case.     

Behavior of bridge girders with corrugated webs under monotonic and cyclic loading

The focus of this study is to investigate the behavior of plate girders with trapezoidally corrugated webs under fatigue loading. Six girders were tested under both monotonic and cyclic four-point loading arrangements. A relationship between the stress range, F_r, and the number of cycles to failure, N, was developed for the girders. The results from the fatigue tests were related to the current AASHTO specifications and compared with the test results of different types of girders carried out by others. Nonlinear finite element analyses were conducted to study the effects of the different geometrical parameters of this type of girders on the stress concentrations at different locations and to explain the findings of the experimental study. Two sources of stress concentration leading to fatigue cracking were isolated and evaluated; one is dependent on the radius of curvature between the web folds and the other depends on the inclination angle of the inclined fold. An analytical technique based on fracture mechanics is also proposed to enable designers to determine the fatigue life of corrugated web steel girders.     

Arabic handwritten digit recognition

In this paper, we fill a gap in the literature by studying the problem of Arabic handwritten digit recognition. The performances of different classification and feature extraction techniques on recognizing Arabic digits are going to be reported to serve as a benchmark for future work on the problem. The performance of well known classifiers and feature extraction techniques will be reported in addition to a novel feature extraction technique we present in this paper that gives a high accuracy and competes with the state-of-the-art techniques. A total of 54 different classifier/features combinations will be evaluated on Arabic digits in terms of accuracy and classification time. The results are analyzed and the problem of the digit ‘0’ is identified with a proposed method to solve it. Moreover, we propose a strategy to select and design an optimal two-stage system out of our study and, hence, we suggest a fast two-stage classification system for Arabic digits which achieves as high accuracy as the highest classifier/features combination but with much less recognition time.     

Performance of glass fiber reinforced polymer bars under elevated temperatures

This paper investigates the residual tensile properties of newly developed glass fiber reinforced polymer (GFRP) bars after being subjected to elevated temperatures for different periods. A total of 120 GFRP specimens were tested in this study. Half of the samples were covered with concrete while the other half were bare bars. The specimens were subjected to three different controlled temperatures (100, 200 and 300 °C) for three different periods (1, 2, and 3 h). Test results showed that almost no losses were observed in the tensile modulus after all exposure periods and temperatures. Losses in the tensile strength, proportional to the level of temperature and exposure period, were recorded. The bars with concrete cover showed higher residual tensile strength compared to their counterparts without coating. The concrete cover was more effective at the lowest temperature level (100 °C) and at the shortest time period (1 h). Scanning Electronic Microscopy (SEM) technique was also used to investigate the effect of elevated temperature on the degradation mechanism of the GFRP bars. The results showed that increasing the temperature level affected the resin matrix surrounding the glass fibers and consequently affected the bond between the fibers and the matrix.     

Virtual-water content of agricultural production and food trade balance of Tunisia

This article is devoted to the assessment of Tunisian agricultural production and food trade balance water-equivalent. A linear regression model relating annual rainfall to crop yields is developed to estimate the agricultural production water-equivalent. Its implementation is based on national data for crop and animal production, leading to food demand water-equivalent quantification. Results highlight the relationship between agricultural and water policies and provide a picture of food security in the country in relation to local agricultural production, and to virtual water fluxes related to foodstuffs trade balance.     

Maximal limited similarity-based rough set model

Non-symmetric similarity relation-based rough set model (NS-RSM) is viewed as mathematical tool to deal with the analysis of imprecise and uncertain information in incomplete information systems with “?” values. NS-RSM relies on the concept of non-symmetric similarity relation to group equivalent objects and generate knowledge granules that are then used to approximate the target set. However, NS-RSM results in unpromising approximation space when addressing inconsistent data sets that have lots of boundary objects. This is because objects in the same similarity classes are not necessarily similar to each other and may belong to different target classes. To enhance NS-RSM capability, we introduce the maximal limited similarity-based rough set model (MLS-RSM) which describes the maximal collection of indistinguishable objects that are limited tolerance to each other in similarity classes. This allows accurate computation to be done for the approximation space. Furthermore, approximation accuracy comparisons have been conducted among NS-RSM and MLS-RSM. The results demonstrate that MLS-RSM model outperforms NS-RSM and can approximate the target set more efficiently.