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31.
Image analysis is an interesting research area with a large variety of challenging applications. Researchers have worked from
decades on this topic, as witnessed by the scientific literature. However, document image analysis is the special case in
image analysis as their spatial properties are different from natural images. Therefore, the main focus of this paper is to
describe image denoising issues in general and document image issues in particular. Since the field of document processing
is relatively new, it is also dynamic, so current methods have room for improvement and innovations are still being made.
Several algorithms proposed in the literature are described. Critical discussions are reported about the current status of
the field and open problems are highlighted. It is also demonstrated that, there are rarely definitive techniques for all
cases of a certain problem. We surveyed the state of art, analyzed recent trends and tried to identify challenges for future
research in this field. 相似文献
32.
In this study effects of the preparation method on the characteristic properties and CO oxidation activities of Ag2O/Co3O4 catalysts were investigated. Catalysts were prepared by two different methods: sol gel and co-precipitation. N2 physisorption measurements, X-ray diffraction, and scanning electron microscopy measurements were used to characterize the catalysts. CO oxidation activity tests were carried out under 1% CO, 21% O2, and the remainder He feed condition between 20° and 200°C. According to the N2 physisorption measurements, catalysts prepared by the co-precipitation method have a higher surface area than the catalysts prepared by the sol-gel method. Co3O4 and AgCoO2 phases were obtained from catalysts prepared by both techniques. In addition to these phases, metallic silver peaks were obtained by increasing calcination temperature. SEM micrographs of the catalysts showed that catalysts have uniform particles. Increasing the calcination temperature caused the formation of different-sized agglomerates and an increase in the gaps between agglomerates. The best activity was obtained from the Ag2 O/Co3 O4 catalyst calcined at 200°C and prepared by the co-precipitation method. This catalyst gave 50% CO conversion at 106°C. The other two catalysts gave 100% CO conversion at a higher temperature of 200°C. 相似文献
33.
Reviews the book, Cross-cultural research methods in psychology edited by David Matsumoto and Fons J. R. Van de Vijver (see record 2010-22491-000). The purpose of this book is to further the potential of cross-cultural psychology by helping researchers to understand the unique difficulties inherent in the field and the current methodologies used to advance quality research. Matsumoto and van de Vijver have compiled a comprehensive yet simply organized volume that speaks to the theoretical and analytic issues met by graduate students and advanced researchers alike. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
34.
Additional rolling fatigue experiments as well as pure sliding, bending, and scratching tests of the Si3 N 4 sand-blasted steel surface have been carried out. Acquired results reconfirm the extraordinary tenacity of the self-attaching Si3 N 4 surface layer in terms of both anti-fatigue and antiwear characteristics, especially in the “hybrid” ball bearing. It appears that this Si3 N 4 sand layer can be identified as a complex, self-organizing, and adaptive system. 相似文献
35.
A. E. Saba A. E. El Sherif E. M. Elsayed 《JOM Journal of the Minerals, Metals and Materials Society》2007,59(10):53-57
Copper is usually present in concentrations less than 5 g/L−1 in dilute waste solutions. The low concentrations make these solutions unsuitable for the electro-flow owinning processes
via conventional electrolysis cells. Unconventional, two-and three-dimensional electrode cells with relatively large cathodic
area are essential for such treatment. Different types of cells are mentioned in the literature. Among these cells, the two-dimensional
Swiss-roll cell (SR) is considered in this study. The effects of cathodic current densities, initial copper concentrations,
free sulfuric acid concentration, the presence of iron and zinc cations, and the rate of flow of the solution on both the
cathodic current efficiency and power consumption were studied. Copper was removed from synthetic and industrial mixtures
of Cu/Fe/Zn sulfate solutions to less than 5 ppm with power consumptions of 10.326 kWh/kg−1 and 8.61 kWh/kg−1, respectively. The correlation between the SR cell and packed-column cell on such treatment was also considered. 相似文献
36.
Saba Mylvaganam 《Particulate Science and Technology》2003,21(3):293-301
Acoustic emission (AE) has been used in many applications in the field of particle science and technology. AE sensors have been used in particle concentration measurements both in gas-continuous and oil-continuous flows in the oil and gas industry. To avoid formation sand flowing into pipelines, leading to erosion of valves and in many cases even to complete blockage of the flow of oil and gas, AE sensors are almost exclusively used in sand monitoring and control. These are very often among standard sensors stipulated by the operators of oil and gas production facilities in offshore, on shore, and subsea applications. Special types of sensor design have led to easy mounting of these AE sensors, which are very often clamp-on devices. This article presents a brief overview of AE-based particle monitoring in general and focuses on flange-mounted sensors in the monitoring of particle flow. By using two or more AE sensors located suitably in the process line, the particle velocity can also be evaluated, as is shown in examples using correlation in this article. The AE sensors can easily be adapted to detect malfunctioning of the process line, whether pneumatic lines or silos, just by analyzing the time series of signals from strategically based AE sensors along the process lines. Some examples are given based on recent measurement data. Finally, the article presents an overview of possibilities for improved particle flow monitoring using a multisensor suite incorporating AE sensors with other sensors/detectors such as those derived from capacitance, resistance, gamma ray, microwave, and optical devices. Artificial intelligence (AI) techniques, such as fuzzy logic and neural network algorithms, used in handling the data from these sensors lead to faster and more reliable control. Some of these topics are addressed also. 相似文献
37.
SangUk Han Farzaneh Saba SangHyun Lee Yasser Mohamed Feniosky Peña-Mora 《Accident; analysis and prevention》2014
It is not unusual to observe that actual schedule and quality performances are different from planned performances (e.g., schedule delay and rework) during a construction project. Such differences often result in production pressure (e.g., being pressed to work faster). Previous studies demonstrated that such production pressure negatively affects safety performance. However, the process by which production pressure influences safety performance, and to what extent, has not been fully investigated. As a result, the impact of production pressure has not been incorporated much into safety management in practice. In an effort to address this issue, this paper examines how production pressure relates to safety performance over time by identifying their feedback processes. A conceptual causal loop diagram is created to identify the relationship between schedule and quality performances (e.g., schedule delays and rework) and the components related to a safety program (e.g., workers’ perceptions of safety, safety training, safety supervision, and crew size). A case study is then experimentally undertaken to investigate this relationship with accident occurrence with the use of data collected from a construction site; the case study is used to build a System Dynamics (SD) model. The SD model, then, is validated through inequality statistics analysis. Sensitivity analysis and statistical screening techniques further permit an evaluation of the impact of the managerial components on accident occurrence. The results of the case study indicate that schedule delays and rework are the critical factors affecting accident occurrence for the monitored project. 相似文献
38.
39.
Karsten J. Quint Stefan Hartmann Steffen Rothe Nicolas Saba Kurt Steinhoff 《Computational Mechanics》2011,48(1):81-96
An accurate prediction of the temperature distribution in space and time plays an important role in many industrial applications,
in particular when phase transformations are involved. In this article the thermo-physical properties of steel 51CrV4 (SAE
6150) are determined and used in numerical simulations. For the simulation of the temperature field a semi-discrete approach
is used, consisting of a finite element approximation in space and a high order Runge– Kutta integration in time. Several
adaptive high-order time integration method (stiffly accurate diagonally implicit Runge–Kutta methods) are applied and their
computational efficiency is investigated. The theoretical rates of convergence are achieved for all problems, including the
non-linear case. Whereas the second order accurate method of Ellsiepen with time adaptive step-size control proves to be most
efficient. Further, the influence of the material model on the simulation results is studied and the numerical results are
verified by experiments. The best correlation of the simulation and experimental data is achieved using temperature-dependent
parameters. 相似文献
40.
This study examined 117 patients with mild cervical atypia or atypical squamous cells of uncertain significance; it was found that 25% had histologically proven CIN lesions by colposcopically-directed punch biopsy or cone biopsy. 18% were found to have at least CIN 2 lesions and there was 1 case of invasive cancer. These data strongly support the recommendation of early colposcopic referral in patients with mild cervical atypia. 相似文献