464 research outputs found

    Application of neural network observer for on-line estimation of salient-pole synchronous generators' dynamic parameters using the operating data

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    Parameter identification is critical for modern control strategies in electrical power systems which is considered both dynamic performance and energy efficiency. This paper presents a novel application of ANN observers in estimating and tracking Salient-Pole Synchronous Generator Dynamic Parameters using time-domain, on-line disturbance measurements. The data for training ANN Observers are obtained through off-line simulations of a salient-pole synchronous generator operating in a one-machine-infinite-bus environment. The Levenberg-Marquardt algorithm has been adopted and assimilated into the back-propagation learning algorithm for training feed-forward neural networks. The inputs of ANNs are organized in conformity with the results of the observability analysis of synchronous generator dynamic parameters in its dynamic behavior. A collection of ANNs with same inputs but different outputs are developed to determine a set of the dynamic parameters. The ANNs are employed to estimate the dynamic parameters by the measurements which are carried out within each kind of fault separately. The trained ANNs are tested with on-line measurements to identify the dynamic parameters. Simulation studies indicate the ANN observer has a great ability to identify the dynamic parameters of salient-pole synchronous generator. The results also show that the tests which have given better results in estimation of each dynamic parameter can be obtained

    Assessing iranian adolescent girls' needs for sexual and reproductive health information

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    Purpose To explore the views and experiences of adolescent girls and key adults regarding the necessity of providing sexual and reproductive health (SRH) information and services for adolescent girls in Iran. Methods This was a qualitative study; the data were coded and categorized in content analysis by MAXQDA10 and were gathered through focus groups with adolescent girls and their mothers and semi-structured interviews with school counselors, sociologists, health providers, state and nongovernmental directors of health programs, clergy, and health policy makers in the Iranian cities of Mashhad, Tehran, Shahroud, and Qom. Results There were six main reasons for the need to provide SRH services for adolescent girls: a lack of adequate knowledge about SRH, easy access to inaccurate information sources, cultural and social changes, increasing risky sexual behaviors among adolescents, religion's emphasis on sex training of children and adolescents, and the existence of cultural taboos. Conclusions Most participants confirmed the necessity of providing SRH services for adolescent girls, so instead of talking about provision or non-provision of these services, it is important for policy makers to plan and provide SRH services that can be consistent with cultural and religious values for adolescent girls. © 2014 Society for Adolescent Health and Medicine. All rights reserved

    Determination of LC50 of copper in Litopenaeus vannamei

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    We determined the LC50 of copper (as CUSO_4) and it's Maximum Allowable Concentration (MAC) for Litopenaeus vannamei. The study was performed in 2003 for which bioassays were used for acute toxicity tests in a period of 96 hours during which water parameters such as water temperature, pH, dissolved oxygen, hardness, alkalinity were also measured. Ten treatments and three replicates for each treatment were used. A LC50 of 86.71, 27.28, 7.98 and 3.90mg/1 and also Maximum Allowable Concentration of 8.671, 2.728, 0.798 and 0.390mg/1 were determined at 24, 48, 72 and 96 hours post exposure. Results showed that L. vannamei is relatively resistant to copper. Hence, short period application of copper to white shrimp farms for controlling algal bloom is judged harmless to the fish

    Family medicine in Iran: facing the health system challenges

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    OBJECTIVE: This study aimed to understand the perspectives of policy makers and decision makers of Iran's health system about the implementation of family medicine in Iran urban areas. MATERIALS/PATIENTS & METHODS: This study is a qualitative study with framework analysis. Purposive semi-structured interviews were conducted with Policy and decision makers in the five main organizations of Iran health care system. The codes were extracted using inductive and deductive methods. RESULTS: According to 27 semi-structured interviews were conducted with Policy and decision makers, three main themes and 8 subthemes extracted, including: The development of referral system, better access to health care and the management of chronic diseases. CONCLUSION: Family medicine is a viable means for a series of crucial reforms in the face of the current challenges of health system. Implementation of family medicine can strengthen the PHC model in Iran urban areas. Attempting to create a general consensus among various stakeholders is essential for effective implementation of the project. BACKGROUND: In response to the current fragmented context of health systems, it is essential to support the revitalization of primary health care in order to provide a stronger sense of direction and integrity. Around the world, family medicine recognized as a core discipline for strengthening primary health care setting

    High-Sensitivity and Compact Time Domain Soil Moisture Sensor Using Dispersive Phase Shifter for Complex Permittivity Measurement

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    This article presents a time domain transmissometry soil moisture sensor (TDT-SMS) using a dispersive phase shifter (DPS), consisting of an interdigital capacitor that is loaded with a stacked four-turn complementary spiral resonator (S4-CSR). Soil moisture measurement technique of the proposed sensor is based on the complex permittivity sensing property of a DPS in time domain. Soil relative permittivity which varies with its moisture content is measured by burying the DPS under a soil mass and changing its phase difference while excited with a 114-MHz sine wave (single tone). DPS output phase and magnitude are compared with the reference signal and measured with a phase/loss detector. The proposed sensor exhibits accuracy better than ±1.2% at the highest volumetric water content (VWC = 30%) for sandy-type soil. Precise design guide is developed and simulations are performed to achieve a highly sensitive sensor. The measurement results validate the accuracy of theoretical analysis and design procedure. Owning the advantages of low profile, low power consumption, and high sensitivity makes the proposed TDT-SMS a good candidate for precision farming and internet of things (IoT) systems

    Low-profile dual-band pixelated defected ground antenna for multistandard IoT devices.

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    A low-profile dual-band pixelated defected ground antenna has been proposed at 3.5 GHz and 5.8 GHz bands. This work presents a flexible design guide for achieving single-band and dual-band antenna using pixelated defected ground (PDG). The unique pixelated defected ground has been designed using the binary particle swarm optimization (BPSO) algorithm. Computer Simulation Technology Microwave Studio incorporated with Matlab has been utilized in the antenna design process. The PDG configuration provides freedom of exploration to achieve the desired antenna performance. Compact antenna design can be achieved by making the best use of designated design space on the defected ground (DG) plane. Further, a V-shaped transfer function based on BPSO with fast convergence allows us to efficiently implement the PDG technique. In the design procedure, pixelization is applied to a small rectangular region of the ground plane. The square pixels on the designated defected ground area of the antenna have been formed using a binary bit string, consisting of 512 bits taken during each iteration of the algorithm. The PDG method is concerned with the shape of the DG and does not rely on the geometrical dimension analysis used in traditional defected ground antennas. Initially, three single band antennas have been designed at 3.5 GHz, 5.2 GHz and 5.8 GHz using PDG technique. Finally, same PDG area has been used to design a dual-band antenna at 3.5 GHz and 5.8 GHz. The proposed antenna exhibits almost omnidirectional radiation performance with nearly 90% efficiency. It also shows dual radiation pattern property with similar patterns having different polarizations at each operational band. The antenna is fabricated on a ROGERS RO4003 substrate with 1.52 mm thickness. Reflection coefficient and radiation patterns are measured to validate its performance. The simulated and measured results of the antenna are closely correlated. The proposed antenna is suitable for different applications in Internet of Things

    Impacts of using a social robot to teach music to children with low-functioning autism

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    This article endeavors to present the impact of conducting robot-assisted music-based intervention sessions for children with low-functioning (LF) autism. To this end, a drum/xylophone playing robot is used to teach basic concepts of how to play the instruments to four participants with LF autism during nine educational sessions. The main findings of this study are compared to similar studies conducted with children with high-functioning autism. Our main findings indicated that the stereotyped behaviors of all the subjects decreased during the course of the program with an approximate large Cohen’s d effect size. Moreover, the children showed some improvement in imitation, joint attention, and social skills from the Pre-Test to Post-Test. In addition, regarding music education, we indicated that while the children could not pass a test on the music notes or reading music phrases items because of their cognitive deficits, they showed acceptable improvements (with a large Cohen’s d effect size) in the Stambak Rhythm Reproduction Test, which means that some rhythm learning occurred for the LF participants. In addition, we indicated that parenting stress levels decreased during the program. This study presents some potential possibilities of performing robot-assisted interventions for children with LF autism

    Inhibitory Effects of Several Essential Oils towards Salmonella typhimurium, Salmonella paratyphi A and Salmonella paratyphi B

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    Plant essential oils are natural products extracted from plants and because of their antimicrobial properties can be used as natural additives in foods. They are also useful for decontamination of food-borne pathogens and can be a safe additive in foods. The antimicrobial activities of essential oils belonging to Saturiea hortensis, Thymus vulgaris, Mentha polegium, Cuminum cyminum, Lavandula officinalis and Mentha viridis L. (spearmint) were investigated at different concentrations (0.1, 0.3, 0.5, 1, 2, 5 and 10%v/v) against Salmonella typhimurium, Salmonella paratyphi A and Salmonella paratyphi B by using the agar well diffusion method. Essential oils showed inhibitory effect on Salmonella spp. in the agar well diffusion assay. In addition, the capability of essential oils for decontamination of minced row beef, ground beef, minced raw chicken and minced raw fish inoculated with Salmonella spp. at 0.1 and 0.5%v/v were assessed. Reduction of the Salmonella spp. population was observed following the inoculation of the cultures with 0.1 and 0.5%v/v essential oils
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