A Family of Interleaved High Step-Up DC-DC Converters by Integrating a Voltage Multiplier and an Active Clamp Circuits

A family of interleaved current-fed high step-up dc-dc converters are introduced and analyzed here by combining a voltage multiplier (VM) and an active clamp circuit for high-voltage high-power applications. Low input currents and output voltages ripples values and high voltage-gains characteristics of these converters make them suitable for lots of dc-dc applications. All power devices operate entirely under soft switching conditions, even when wide load and input voltage variations are applied. Thus, they can be designed at high switching frequencies to reduce passive components sizes to achieve high-power density, one of the main targets of the power electronics researches. Also, their input and output ports common ground simplifies the gate-drives and control circuits. To verify the given analyses and simulations, a 120-320 V to 1 kV, 50-1300 W three-stage two-leg prototype converter has been implemented at 100 kHz. Based on the experimental results, maximum efficiency of 96.5% is achieved.Comment: 14 pages, 15 figure

Relationship between self-esteem and burnout in nurses

زمینه و هدف: عزت نفس عامل اصلی و اساسی در سازگاری عاطفی- اجتماعی بوده و بر تمام سطوح زندگی از جمله بر فعالیت های فرد تأثیر می گذارد. با توجه به شیوع بالای فرسودگی شغلی در میان پرستاران، این مطالعه با هدف تعیین ارتباط بین عزت نفس و فرسودگی شغلی پرستاران انجام شد. روش بررسی: در این مطالعه توصیفی- همبستگی، 300 پرستار شاغل در بخش های ICU، سوختگی و اورژانس بیمارستان های آموزشی شهر اهواز در سال 1392 به روش سرشماری انتخاب و وارد مطالعه شدند. داده ها به وسیله پرسشنامه های اطلاعات دموگرافیک، فرسودگی شغلی ماسلاچ و عزت نفس کوپر اسمیت جمع آوری و عزت نفس و فرسودگی شغلی پرستاران مورد ارزیابی قرار گرفت. یافته ها: در این مطالعه اکثریت پرستاران (248 نفر) مؤنث (7/82) بودند و میانگین سنی نمونه ها 92/4±76/30 سال بود. میانگین نمره عزت نفس پرستاران 74/28±91/81 به دست آمد. نتایج فرسودگی نشان داد اکثر پرستاران به جز در بعد شدت خستگی هیجانی و مسخ شخصیت، در سایر ابعاد دچار سطوح متوسط فرسودگی شغلی بودند. تنها میان عزت نفس و فراوانی کفایت فردی همبستگی معنی داری وجود داشت (035/0P=، 105/0-r=). بین عزت نفس و سایر ابعاد فرسودگی همبستگی مشاهده شد؛ اما این ارتباط از نظر آماری معنی دار نبود (0.0

Bridging the semantic gap for software effort estimation by hierarchical feature selection techniques

Software project management is one of the significant activates in the software development process. Software Development Effort Estimation (SDEE) is a challenging task in the software project management. SDEE is an old activity in computer industry from 1940s and has been reviewed several times. A SDEE model is appropriate if it provides the accuracy and confidence simultaneously before software project contract. Due to the uncertain nature of development estimates and in order to increase the accuracy, researchers recently have focused on machine learning techniques. Choosing the most effective features to achieve higher accuracy in machine learning is crucial. In this paper, for narrowing the semantic gap in SDEE, a hierarchical method of filter and wrapper Feature Selection (FS) techniques and a fused measurement criteria are developed in a two-phase approach. In the first phase, two stage filter FS methods provide start sets for wrapper FS techniques. In the second phase, a fused criterion is proposed for measuring accuracy in wrapper FS techniques. Experimental results show the validity and efficiency of the proposed approach for SDEE over a variety of standard datasets

Using Theory CMOS Active Inductors in Low Noise Amplifier

ABSTRACT In this paper we present LNA with active inductor circuits are employed to assess their suitability for providing a tuning function in HEMT circuits. Comparisonof measurement and simulation ofan active inductor shows the high quality factor. Simulations ofthe low noise amplifier show the advantages of active inductorswith similar performance even in regard to the nois

The effect of the Iranian health transformation plan on hospitalization rate: Insights from an interrupted time series analysis

Background: Healthcare policy- and decision-makers make efforts to build and maintain high-performing and effective health systems, implementing effectiveness programs and health reforms. In May 2014, the Iranian Ministry of Health and Medical Education has launched a series of ambitious reforms, known as the Health Transformation Plan (HTP). This study aimed to determine the effect of the HTP on hospitalization rate in Iranian public hospitals affiliated to the Ministry of Health and Medical Education. Methods: This study was designed as a quasi-experimental, counterfactual study utilizing the interrupted time series analysis (ITSA), comparing the trend of hospitalization rate before and after the HTP implementation in 16 hospitals in the Lorestan province. Data was collected from March 2012 to February 2019. Results: In the first month of the HTP implementation, an increase of 2.627 95% CI: 1.62-3.63 was noted (P < 0.001). Hospitalization rate increased by 0.68 95% CI: 0.32-0.85 after the HTP implementation compared to the first month after the launch of the HTP (P < 0.001). After the HTP implementation, monthly hospitalization rate per 1000 persons significantly increased by 0.049 95% CI: 0.023-0.076 (P < 0.001). Conclusions: The HTP implementation has resulted in an increased hospitalization rate. Health planners should continue to further improve this service. ITSA can play a role in evaluating the impact of a given health policy. © 2020 The Author(s)

Mapping Listvenite Occurrences in the Damage Zones of Northern Victoria Land, Antarctica Using ASTER Satellite Remote Sensing Data

Listvenites normally form during hydrothermal/metasomatic alteration of mafic and ultramafic rocks and represent a key indicator for the occurrence of ore mineralizations in orogenic systems. Hydrothermal/metasomatic alteration mineral assemblages are one of the significant indicators for ore mineralizations in the damage zones of major tectonic boundaries, which can be detected using multispectral satellite remote sensing data. In this research, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) multispectral remote sensing data were used to detect listvenite occurrences and alteration mineral assemblages in the poorly exposed damage zones of the boundaries between the Wilson, Bowers and Robertson Bay terranes in Northern Victoria Land (NVL), Antarctica. Spectral information for detecting alteration mineral assemblages and listvenites were extracted at pixel and sub-pixel levels using the Principal Component Analysis (PCA)/Independent Component Analysis (ICA) fusion technique, Linear Spectral Unmixing (LSU) and Constrained Energy Minimization (CEM) algorithms. Mineralogical assemblages containing Fe 2+ , Fe 3+ , Fe-OH, Al-OH, Mg-OH and CO3 spectral absorption features were detected in the damage zones of the study area by implementing PCA/ICA fusion to visible and near infrared (VNIR) and shortwave infrared (SWIR) bands of ASTER. Silicate lithological groups were mapped and discriminated using PCA/ICA fusion to thermal infrared (TIR) bands of ASTER. Fraction images of prospective alteration minerals, including goethite, hematite, jarosite, biotite, kaolinite, muscovite, antigorite, serpentine, talc, actinolite, chlorite, epidote, calcite, dolomite and siderite and possible zones encompassing listvenite occurrences were produced using LSU and CEM algorithms to ASTER VNIR+SWIR spectral bands. Several potential zones for listvenite occurrences were identified, typically in association with mafic metavolcanic rocks (Glasgow Volcanics) in the Bowers Mountains.Comparison of the remote sensing results with geological investigations in the study area demonstrate invaluable implications of the remote sensing approach for mapping poorly exposed lithological units, detecting possible zones of listvenite occurrences and discriminating subpixel abundance of alteration mineral assemblages in the damage zones of the Wilson-Bowers and Bowers-Robertson Bay terrane boundaries and in intra-Bowers and Wilson terranes fault zones with high fluid flow. The satellite remote sensing approach developed in this research is explicitly pertinent to detecting key alteration mineral indicators for prospecting hydrothermal/metasomatic ore minerals in remote and inaccessible zones situated in other orogenic systems around the world