69 research outputs found
Hybrid and dynamic static criteria models for test case prioritization of web application regression testing
No full textIn software testing domain, different techniques and approaches are used to support the process of regression testing in an effective way. The main approaches include test case minimization, test case selection, and test case prioritization. Test case prioritization techniques improve the performance of regression testing by arranging test cases in such a way that maximize fault detection could be achieved in a shorter time. However, the problems for web testing are the timing for executing test cases and the number of fault detected. The aim of this study is to increase the effectiveness of test case prioritization by proposing an approach that could detect faults earlier at a shorter execution time. This research proposed an approach comprising two models: Hybrid Static Criteria Model (HSCM) and Dynamic Weighting Static Criteria Model (DWSCM). Each model applied three criteria: most common HTTP requests in pages, length of HTTP request chains, and dependency of HTTP requests. These criteria are used to prioritize test cases for web application regression testing. The proposed HSCM utilized clustering technique to group test cases. A hybridized technique was proposed to prioritize test cases by relying on assigned test case priorities from the combination of aforementioned criteria. A dynamic weighting scheme of criteria for prioritizing test cases was used to increase fault detection rate. The findings revealed that, the models comprising enhanced of Average Percentage Fault Detection (APFD), yielded the highest APFD of 98% in DWSCM and 87% in HSCM, which have led to improve effectiveness prioritization models. The findings confirmed the ability of the proposed techniques in improving web application regression testing
Multiscale design of nonlinear materials using a shape optimization scheme based on an interface-enriched GFEM
No full textMotivated by key advances in manufacturing techniques, the tailoring of materials with specific macroscopic properties has been the focus of active research in mechanical engineering and materials science over the past decade. The key challenge in this line of work is how to optimize the material microstructure to achieve a desired macroscopic constitutive response. The overwhelming majority of this type of inverse design work relies on topology optimization based, primarily, on linear theory.
In this work, we develop and implement a method to design particulate composites at the mesoscale using a shape optimization scheme to minimize or maximize a nonlinear cost function at the macroscale while satisfying a set of constraints associated, for example, with the volume fraction of inclusions or with the manufacturing technique. The optimization method relies on three key ‘modules’: multiscale modeling, sensitivity analysis, and optimization.
The multiscale modeling is based on a nonlinear finite element solver, which combines a classical homogenization scheme with a NURBS-based Interface-enriched Generalized Finite Element Method (NIGFEM) used to capture accurately and efficiently the displacement field in a heterogeneous material with a finite element discretization that does not conform to the material interfaces. Damage evolution is captured using a three-parameter isotropic damage model able to simulate a wide range of failure responses.
The proposed gradient-based shape optimization scheme relies on the stationary nature of the non-conforming meshes used to discretize the periodic unit cell, thereby avoiding mesh distortion issues that plague conventional finite-element-based shape optimization studies. In the current approach, the finite element approximation space used in the NIGFEM is augmented with NURBS to allow for the accurate capture of the weak discontinuity present along complex, curvilinear material interfaces. NURBS are also used to parameterize the design geometry precisely and compactly by a small number of design variables.
To compute the derivatives of the cost and constraint functions with respect to the design variables, we also formulate an analytic nonlinear sensitivity, which is simplified by the fact that only the enrichment control points on material interfaces move, appear or disappear during the shape optimization process. The derivations uncover subtle but important new terms involved in the sensitivity of shape functions and their spatial derivatives. Our analytic nonlinear shape sensitivity avoids the technical difficulties encountered in the finite difference or semi-analytical schemes when the boundary intersects an element very close to a node in a non-conforming mesh. In these situations, the boundary may move to another element during the design perturbation step, resulting in changes of the mesh topology, making the differentiation of the stiffness matrix and load vector problematic.
We apply the NIGFEM shape optimization scheme to several 2D and 3D structural problems including some benchmark and application examples to demonstrate the performance and accuracy of the method. Based on the multiscale approach, we also design the microstructure of a periodic particulate composite to optimize the volume fraction and distribution of the inclusions for a desired macroscopic nonlinear stress-strain curve.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2018-12-01The student, Ahmad Raeisi Najafi, accepted the attached license on 2016-07-26 at 15:58.The student, Ahmad Raeisi Najafi, submitted this Dissertation for approval on 2016-07-26 at 16:00.This Dissertation was approved for publication on 2016-07-28 at 08:47.DSpace SAF Submission Ingestion Package generated from Vireo submission #10089 on 2017-02-28 at 14:35:36Made available in DSpace on 2017-03-01T16:36:34Z (GMT). No. of bitstreams: 2
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Previous issue date: 2016-07-28Embargo set by: Seth Robbins for item 98558
Lift date: 2019-03-01T16:37:19Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 98558 on 2019-03-02T10:15:30Z
Prevalence and antibiotic resistance pattern of bacteria isolated from urinary tract infections in Northern Iran
No full textBackground: This study aimed to investigate the bacteria associated with urinary tract infection (UTI) and antibiotic susceptibility pattern of the isolates during 2013–2015 in Northern Iran. Materials and Methods: Overall 3798 patients with clinical symptoms of UTI were subjected as samples, and they were cultured and pure isolated bacteria were identified using biochemical tests and subjected to antibiogram assessment using disc diffusion method. Results: Totally, 568 (14.96%) from 3798 patients had positive UTI. Four hundred and ninety-seven (87.5%) from 568 isolated bacteria were resistant to at least one antibiotic. Escherichia coli, Staphylococcus spp., and Pseudomonas spp. were the most prevalent bacteria. Isolated bacteria indicated the highest antibiotic resistance to methicillin (76.06%) and ampicillin (89.29%) and also revealed the most sensitivity to imipenem (99.1%) and amikacin (91.57%). Statistical analysis of the resistance pattern trend during 3 years indicated the insignificant increase (P > 0.05) in antibiotic resistance of the isolates. Conclusion: The results of this study revealed a great concern for emerging UTI-related multidrug-resistant strains of bacteria causing UTI in Iran
The interrelationship between choice of course of study abroad and participation in online social networks
No full textThis thesis examines how the choice of course of study abroad interrelates with participation in online social networks, and provides an application of semiotics to research in choice and decision making in higher education and information systems research. The study itself is justified by the increasing need to consider students’ choice of course of study as a separate phenomenon from their choice of institution or host country. Alongside the adoption of a more nuanced view of student selection, the author also recognises the need to understand the role of online social networks within the decision-making process for selecting higher education courses. This work adopts an interpretivist philosophy and utilises a comparative case study method, drawing upon semi-structured interviews with international MBA students in addition to relevant documentation. The thesis finds a strong interplay between the choice of course of study abroad and participation in online social networks
Effect of walnut kernel septum membranes hydroalcoholic extract on the shelf life of traditional butter
No full textIncorporation of natural ingredients antioxidants in edible fats can profitably affect their oxidative stability during production and storage. The purposes of the current work were to assess the antioxidant and antimicrobial effect of walnut kernel septum membranes hydroalcohol extract (WHE) in traditional butter (TB). Antioxidant characterization of the extract was screened through methods of DPPH, reducing power and total phenolic assays. After preparation of traditional butter from yogurt, WHE was incorporated into TB at three different concentrations; 0.05, 0.1 and 0.5 and compared with a control, BHT and tocopherol treated samples (200 mg of BHT and tocopherol/kg). Microbiological studies (Staphylococcus aureus, Coliforms, Psychrotrophic bacteria, yeasts and molds) were done during 90 days of storage time. Changes in Anisidine value (AV), acid value, peroxide value (PV) free fatty acids (FFA), Schaal and Totox value were monitored at 45-day intervals. Sensory evaluation was done using 10 semi-trained panelists based on the 5-point hedonic scale. It was found that the total phenolic content of WHE was 368.86 mg GAE/g. The BHT had higher antioxidant activity than WHE inhibiting 92.3 of the DPPH radical at 600 μg/mL. Peroxide value of TB treated with tocopherol, BHT and WHE 0.5 was 0.29 ± 0.07, 0.39 ± 0.07 and 0.52 ± 0.04 respectively. Furthermore, the WHE incorporated butter has shown low levels of free fatty acids, Schaal and Totox value when compared to control treatment. The WHE 0.5 incorporated sample had the most antimicrobial activity and it inhibited the growth of all the microorganisms (except Staphylococcus aureus) used in the study. Among the treated TB, the samples treated with the control and WHE 0.05 had the highest sensory attributes score. The study showed that WHE could be an excellent natural origin of antimicrobial and antioxidant agents which can be used in butter. © 2019 The Author
The Determinants of Hypertension and Commitment to Implementing a Nutrition Program Based on the Pender Health Promotion Model
No full textBackground and objective: The high prevalence of hypertension and its serious complications on body organs have made the disease a major health problem in all communities across the world. Given the high burden of hypertension, the present study was aimed at investigating the determinants factors of hypertension and commitment to implementing a nutritional program based on the Pender Health Promotion Model.
Methods:Across-sectional survey was conducted on 420 patients with hypertension supervised by the urban health centers of Gorgan city health district. Sampling technique was random multi-stage cluster sampling. Data was collected using a standard questionnaire based on the Pender Health Promotion Model (HPM). To analyze, descriptive methods and inferential statistical tests including independent t-test, one-way ANOVA, pearson correlation coefficient and linear regression model were used through SPSS version 18. The significance level was considered less than 0.05.
Results: The results showed that 386 (91.9%) had no drug changes based on doctor comment and 352 (83.8%) did not use any drugs to control blood pressure. Statistical tests reported that commitment to implementing nutrition program had a remarkable differences with perceived barriers (p=0.001), self-efficacy (p=0.001), feelings related to behavior (p=0.001), situational determinants (P=0.038), and interpersonal factors (p=0.001).
Conclusion: The score of most constructs of the HPM was moderate; therefore, designing the effective interventions using HPM may be helpful in controlling hypertension.
Paper Type:Research Article. کلیدواژهها [English
The Determinants of Hypertension and Commitment to Implementing a Nutrition Program: Application of Pender Health Promotion Model
No full textBackground and objective: The high prevalence of hypertension and its serious complications on body organs have made the disease a major health problem in all communities across the world. Given the high burden of hypertension, the present study was aimed at investigating the determinants factors of hypertension and commitment to implementing a nutritional program based on the Pender Health Promotion Model. Methods:Across-sectional survey was conducted on 420 patients with hypertension supervised by the urban health centers of Gorgan city health district. Sampling technique was random multi-stage cluster sampling. Data was collected using a standard questionnaire based on the Pender Health Promotion Model (HPM). To analyze, descriptive methods and inferential statistical tests including independent t-test, one-way ANOVA, pearson correlation coefficient and linear regression model were used through SPSS version 18. The significance level was considered less than 0.05. Results: The results showed that 386 (91.9%) had no drug changes based on doctor comment and 352 (83.8%) did not use any drugs to control blood pressure. Statistical tests reported that commitment to implementing nutrition program had a remarkable differences with perceived barriers (p=0.001), self-efficacy (p=0.001), feelings related to behavior (p=0.001), situational determinants (P=0.038), and interpersonal factors (p=0.001). Conclusion: The score of most constructs of the HPM was moderate; therefore, designing the effective interventions using HPM may be helpful in controlling hypertension. Paper Type:Research Article
Chemical Composition and Antifungal Effect of Echinophora platyloba Essential Oil against Aspergillus flavus, Penicillium expansum and Fusarium graminearum
No full textMolds are one of the most important causes of food spoilage that produce toxic substances called mycotoxins, which endanger the consumer health. The adverse effects of synthetic food preservatives consumption made researches to focus on application of natural preservatives in order to increase shelf life of food as well as prevention of harmful effects of chemical preservatives. The present study was conducted to investigate the effects of Echinophora platyloba essential oil on spore growth of Aspergillus flavus, Penicillium expansum and Fusarium graminearum. The essential oil composition of E. platyloba was analyzed by gas chromatography–mass spectrometry (GC-MS) and its antifungal effect was evaluated by disk diffusion and micro dilution methods. Results revealed that the MIC values of essential oil for A. flavus, P. expansum and F. graminearum were 0.625 mg.mL-1, 0.625 mg.mL-1 and 0.3125 mg.mL-1 and the MFC values were 0.625 mg.mL-1, 1.250 mg.mL-1 and 0.625 mg.mL-1. The essential oil had the highest and the lowest anti-fungal effect on F. graminearum and A. flavus respectively. In conclusion, due to notable antifungal effects of E. platyloba essential oil, it can be practically applied as a natural alternative to chemical preservatives in food industry
Effects of Ramadan fasting on common upper gastrointestinal disorders: A review of the literature
No full textIntroduction: Ramadan is the ninth month of Muslim's calendar during which Muslims fast. Ramadan lasts 29-30 days based on the visual sightings of the crescent moon. Fasting during Ramadan has significant health effects. The present study aimed at reviewing the literature of the impact of Ramadan fasting on upper gastrointestinal disorders. Methods: MEDLINE and Google Scholar were searched by using ((“Ramadan” R fasting”) AND( "Upper Gastrointestinal Tract" OR "Gastrointestinal Diseases" OR "Dyspepsia" OR "Gastroesophageal Reflux" OR "Peptic Ulcer" OR "Gastrointestinal Hemorrhage")) as keywords in the title and abstract. Relevant, non- duplicate full articles written in English were reviewed. Results: Gastric acid and pepsin secretion increase during Ramadan fasting, probably associated with dyspeptic symptoms. Regarding peptic ulcer frequency, results are inconsistent. However, peptic ulcer complications such as gastrointestinal bleeding and peptic ulcer perforation increase during Ramadan fasting. Conclusion: Fasting during Ramadan seems to be beneficial for healthy individuals, but in people with gastrointestinal disorders, it might be harmful as it increases the risk of complications. Therefore, taking medical advice before Ramadan fasting is highly recommended to people suffering from gastrointestinal symptoms
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