3,237 research outputs found
An Object-Based Approach to Modelling and Analysis of Failure Properties
In protection systems, when traditional technology is replaced by software, the functionality and complexity of the system is likely to increase. The quantitative evidence normally provided for safety certification of traditional systems cannot be relied upon in software-based systems. Instead there is a need to provide qualitative evidence. As a basis for the required qualitative evidence, we propose an object-based approach that allows modelling of both the application and software domains. From the object class model of a system and a formal specification of the failure properties of its components, we generate a graph of failure propagation over object classes, which is then used to generate a graph in terms of object instances in order to conduct fault tree analysis. The model is validated by comparing the resulting minimal cut sets with those obtained from the fault tree analysis of the original system. The approach is illustrated on a case study based on a protection system from..
A simplified analytical approach for optimal planning of distributed generation in electrical distribution networks
DG-integrated distribution system planning is an imperative issue since the installing of distributed generations (DGs) has many effects on the network operation characteristics, which might cause significant impacts on the system performance. One of the most important characteristics that mostly varies because of the installation of DG units is the power losses. The parameters affecting the value of the power losses are number, location, capacity, and power factor of the DG units. In this paper, a new analytical approach is proposed for optimally installing DGs to minimize power loss in distribution networks. Different parameters of DG are considered and evaluated in order to achieve a high loss reduction in the electrical distribution networks. The algorithm of the proposed approach has been implemented using MATLAB software and has been tested and investigated on 12-bus, 33-bus, and 69-bus IEEE distribution test systems. The results show that the proposed approach can provide an accurate solution via simple algorithm without using exhaustive process of power flow computations
Existence of Solutions for a Class of Quasi-Linear Singular Integro-Differential Equations
2000 Mathematics Subject Classification: 45F15, 45G10, 46B38.An existence theorem is proved for a class of quasi-linear
singular integro-differential equations with Cauchy kernel
Performance of Teaching and Learning Technology Internship Students as Perceived by Their Trainers
The purpose of this descriptive study is to evaluate the performance of teaching and learning technology students of the College of Education, Sultan Qaboos University during their internship experience. Trainers of the interns rated them on 15 items of performance as displayed in the questionnaire of the study. The internal consistency of the questionnaire was significantly high (.96). It was observed that the general level of performance of the interns was high (a mean of 4.40 out of 5) and the ratings of the individual items of performance ranged from 4.04 to 4.59. However, no gender significant differences were observed in the global ratings of males and females. Apart from this, it was found that 2014 cohort interns performed better than earlier cohorts (before 2014). The study reveals other significant findings such as location of internship (public or private sector) did not affect performance of interns. Similarly, type of institution (educational or non-educational) was not a significant factor of performance, however, interns in non-educational institutions performed better (though not significantly) than interns in educational institutions). Interns with higher GPAs outperformed their colleagues with lower GPAs. Keywords: Internship evaluation, supervisors’ ratings of interns, teaching and learning technolog
Alternative Interventions for Children Coping with Chronic Conditions: A Critical Review of the Literature
Reduction of stressors and anxiety levels in adolescents with chronic illnesses is a critical concept in pediatric health care in America today. The many stressors associated with chronic illness include displaying physical and mental differences, social stigma, financial difficulty, and family stress. These stressors may affect the adolescent’s ability to learn and cope in everyday life. The current research was a critical review of the literature examining studies done with adolescents coping with chronic diseases and illnesses. The aim was to analyze the most efficacious non-pharmacological methods for reducing stressors in adolescents with chronic illness. A critical review of the literature of 10 studies was conducted after searching scholarly databases for articles studying physical interventions and their effects on the symptomology of chronic illnesses in youth. We found that physical activity programs are reported to have positive effects on the symptomology, stressors, and overall wellbeing of many children with illnesses, but concluded that more research needs to be conducted in this area before implementing trials of specific exercise interventions due to the high-risk nature of the youth population
Effect of Rosemary and Sweet Marjoram on three Predacious Mites of the Family Phytoseiidae (Acari: Phytoseiidae)
The direct toxicity of two essential oils, Majorana hortensis, Moench and Rosmarinus officinalis L. to adult females of the predacious mites, Amblyseius zaheri Yousef and El-Borolossy, Amblyseius barkeri (Hughes) and Typhlodromus athiasae Porath and Swirski were tested. Rosemary oil was the most toxic to females of A. barkeri and the least to A. zaheri. In contrast,sweet marjoram oil was relatively toxic to T. athiasae and slightly toxic to A. barkeri. Both essential oils,decreased the food consumption rate at the concentration used for A.barkeri and A. zaheri. Females of A. barkeri and A. zaheri suffered a depression in reproduction when treated with 1% of rosemary oil.Both material used seems to be harmless to T. athiasae at 1%
Atypical Presentation of Mollaret’s Meningitis
Mollaret’s meningitis is mostly described in the setting of recurrent attacks of fever along with signs and symptoms of meningitis. It resolves spontaneously without any treatment and in most of the cases no causative organism is identified. Here we present an atypical case of mollaret’s meningitis in which the patient presented with headache and meningismus in the absence of fever
The Role of Green Intellectual Capital in Strengthening the Elements of the Knowledge Economy: An Analytical Descriptive Study of the Opinions of a Sample of Managers in the Oil Products Distribution Company /Iraq- Nineveh
The current research sought to identify the role of the dimensions of green intellectual capital in strengthening the elements of the knowledge economy, by determining the level of the relationship and the impact between them and applying it on the Oil Products Distribution Company in Nineveh, the sample of study was selected intentionally. It consists of (100) managers, as it relies on collecting data and information on the main research tool (questionnaire form), a number of statistical tools have been adopted, namely (correlation coefficient, linear regression). Where many conclusions were presented, the most important of which is indicating a case of the actual contribution of the dimensions of green intellectual capital in strengthening the elements of the knowledge economy in the researched organization. It also made a set of proposals, including the need for more attention to be paid to employing the possibilities and capabilities of green intellectual capital (human, structural, social) towards strengthening the elements of the knowledge economy in the researched organization, in a way that, it contributes to enhancing efforts in support of knowledge economies and achieving added value in all directions
- …