36 research outputs found
ARQUEOLOGÍA DE LARGAS DISTANCIAS Y CIRCULACIÓN DE OBJETOS E IDEAS EN LA REGIÓN PAMPEANA ARGENTINA
No full textEn los últimos años, retomando algunos antecedentes e incorporando nuevas evidencias, las investigaciones arqueológicas convergen en señalar la circulación macrorregional de bienes y conceptos entre las Sierras Centrales, la Región Pampeana y las Tierras Bajas de Argentina. En este marco, y en continuidad con aportes anteriores, presentamos tres casos de estudio que vinculan materialidades arqueológicas distantes entre 300 y 700 km lineales. El primero refiere a tres vasos efigie o “cara gollete” de cerámica hallados en la zona del Bajo Paraná y Delta, con rasgos afines a las representaciones antropomorfas de Sierras Centrales. El segundo vincula las áreas de Tandilia (Región Pampeana) y Ansenuza (llanura oriental de Sierras Centrales) mediante patrones iconográficos y tecno-decorativos aplicados a recipientes cerámicos. El tercer caso conecta a la Sierra de Comechingones, en el extremo sur de Sierras Centrales, con la Sierra de Cura Malal en la Región Pampeana, a través de correspondencias estilísticas entre imágenes rupestres. Al considerar a la Región Pampeana como un espacio de integración macrorregional, estas relaciones pueden aportar evidencias sobre redes arqueológicas implicadas en la circulación de objetos y conceptos a larga distancia entre las Sierras Centrales y las Tierras Bajas de Argentina.
A distributed virtual sensor scheme for marine fuel engines
No full textThis paper proposes a virtual sensor scheme designed to compensate for sensor fault effects in marine fuel engines. The proposed scheme design follows a distributed approach, where the marine fuel engine is decomposed in several subsystems. Then, for each subsystem we design a monitoring agent that can actively compensate for the effects of sensor faults occurring in the specific subsystem. This is realized using virtual sensors that can estimate the sensor fault in order to reconstruct the faulty measurements. Due to the Differential-Algebraic mathematical description of marine fuel engine dynamics, we design three types of virtual sensors; using adaptive observers, Set Inversion via Interval Analysis (SIVIA) and static models. Simulation results are used to illustrate the efficiency of the method.</p
Analysis and Design Rectangular Patch with Half Rectangular Fractal Techniques
No full textAbstractIn this paper, rectangular patch with half rectangular fractal geometry is designed. The proposed antenna is fabricated on RT/duroid 5880 with relative permittivity 2.2 and having dimensions 40mm x 30mm x 1.56mm. HFSS software is used for the design of this antenna. It operates at four frequency bands 3.19-3.29GHz, 3.98-4.09GHz, 5.4-5.46GHz and 5.97-6.06GHz. The proposed antenna can be used in the military for meteorological purpose and satellite communications. The proposed design has return loss –18.5061dB, -22.1394dB, -4.7404dB and -36.2199dB in frequency bands 3.19-3.29GHz, 3.98-4.09GHz, 5.4-5.46GHz and 5.97-6.06GHz
Analysis and Design of Triple Band Compact Microstrip Patch Antenna with Fractal Elements for Wireless Applications
No full textAbstractThis paper presents the design of triple band compact microstrip patch antenna with fractal elements. The antenna has been designed on FR4 substrate with thickness 1.6mm, dielectric constant 4.4 and resonant frequency of antenna is 3.2GHz. Gain of antenna is improved by addition of fractal elements to the nine corners of the nonagon patch. Introduction of fractal elements improved the gain from 1.24dB to 7.96dB and miniaturization takes place due to the decrease in resonant frequency from 3.38GHz to 2.88GHz on increasing the iteration number. The three iterations of antenna is designed and simulated by using HFSS V13 software and the designed antennas covers the frequency bands of WLAN, WiMax and other wireless applications which comes under the frequency ranges of S-band, C-band and X-band
Quad Staircase Shaped Microstrip Patch Antenna for S, C and X Band Applications
No full textAbstractThis paper presents miniaturization by introducing staircase shape at each edge of the patch of Microstrip Patch Antenna (MPA) which operates in S-band (2-4GHz), C-band (4-8GHz) and X-band (8-12GHz). The proposed antenna operates at 2.44GHz, 5.53GHz, 7.79GHz and 9.39GHz with up to 37% size reduction compared to the basic MPA. Design frequency for the proposed antenna is 2.4GHz which supports multiband behavior. The Rogers RT/Duroid 5880 with relative permittivity 2.2 and height 1.6mm is used as substrate material for design of proposed antenna. Transmission line model is applied to calculate the dimensions of the proposed antenna. Coaxial probe feed is used to feed the proposed antenna because this type of feed provides better impedance matching to source by varying the feed position. Ansoft HFSS V13 (High Frequency Structure Simulator) software is used for the design and simulation of the proposed antenna. The results of the proposed antenna are obtained in terms of Return Loss, Voltage Standing Wave Ratio, Gain and Radiation Pattern which have acceptable values of return loss less than -10dB, VSWR less than 2 at each resonant frequencies and Gain more than 3dB
Neurocomputational Models for Parameter Estimation of Circular Microstrip Patch Antennas
No full textAbstractNeurocomputational models eliminates the complex, lengthy and time consuming mathematical procedures for design, analysis and calculating performance parameters of Microstrip antenna. No single ANN based model has been proposed till date for calculating all parameters of circular microstrip antennas simultaneously. This paper presents a Neuro-Computational (NC) approach for estimation of all performance parameters such as Return Loss (RL), Voltage Standing Wave Ratio (VSWR), resonant frequency (fr), Band-Width (BW), Gain(G), Directivity(D) and antenna efficiency(η) of Circular Microstrip Patch Antenna (CMPA) simultaneously. The difficulty in calculating the parameters of these antennas lies due to the involvement of a large number of physical parameters including their associated optimal values. It is indeed very difficult to formulate an exact numerical solution merely on practical observations based empirical studies. In order to circumvent this problem, an alternative solution is achieved using artificial neural network (ANN). Feed-Forward Back-Propagation Artificial Neural Network (FFBP-ANN) trained with Levenberg-Marquardt algorithm is used for estimation of different performance parameters of CMPA. The results of NC estimation are in very agreement with simulated, measured and theoretical results
A comparison of teacher perceptions between a mentorship model in British Columbia
No full textThe purpose of this research study was to examine the experiences of two teachers who experienced different mentorship models – the Newly Qualified Teacher (NQT) year in England and a mentorship program in British Columbia (BC). This narrative study was conducted using semi-structured interviews with the two participants, which were “restoried” into a chronological narrative. Descriptive and second level-coding were used to find themes between both experiences. The findings of the study reveal three similarities between the teachers’ experiences of mentorship: personal relationship between mentor and mentee, practical support, and additional support. The data also revealed three significant differences: the starting point of mentorship for both participants, the role of mentor and the difference in release time. The findings of the study suggest that a wide gap exists between the need and the level of mentorship programming offered for novice teachers in the BC school system. This study contributes to the existing scholarship on teacher mentorship by examining teachers’ perceptions of mentorship supports. The study provides several recommendations for mentorship practices, which are particularly timely as BC moves forward with implementing new mentorship models across the province. These recommendations include proving release time, scheduling time for observations and encouraging TTOC’s to participate in mentorship programs
Primary teachers' experiences in a play-based learning PLC
No full textThis study investigated primary teachers’ perceptions of their experiences participating in a Professional Learning Community (PLC) about Play-Based Learning and their feelings of self-efficacy towards implementing Play-Based Learning. The literature surrounding PLC participation and teacher efficacy consists largely of quantitative studies. This study utilized a phenomenological approach to collect data through participants’ responses to an online open-ended questionnaire and follow-up phone interview. Four themes emerged from the data on primary teachers’ participation in a Play-Based Learning PLC. They are: value in PLC participation, value Play-Based Learning, shared teaching resources to implement Play-Based Learning, and enhanced self-efficacy towards implementing Play-Based Learning. The findings support the role of PLCs, specifically teacher-led PLCs, in developing primary teachers’ collaboration for improving teacher efficacy. The results of this study also support the concept of implementing Play-Based Learning in primary grade classrooms as a way of providing developmentally appropriate learning opportunities
Servant leadership strategies and their impact on teacher professional learning
No full textThis study investigates servant leadership characteristics and their impact on teacher professional learning. This research targets the subject area of Applied Design, Skills, and Technologies
(ADST) from the revised BC Ministry of Education curriculum in 2016. This phenomenological study used a purposeful sampling of participants that, through a series of interviews, explored their professional learning experiences using a servant leadership lens. As ADST is a recently created content area, supporting literature came from the areas of Science, Technology, Engineering, and Math (STEM); Science, Technology, Engineering, Art, and Math (STEAM); and Project Based Learning (PBL). This paper looks at how elements of servant leadership can build a solid foundation of relational trust and support for those teaching in ADST. Furthermore, it examines how that foundation can have an impact on teacher professional learning and growth
Perceptions of support for early career teachers engaged in generative dialogue
No full textEarly career teachers (ECTs) face a number of challenges, and in this study, generative dialogue was introduced as a framework to provide support for ECTs. A review of the literature on ECTs indicates that support plays a critical role in addressing the challenges they face, and that factors such as isolation and connection, professional learning, and teacher dialogue all relate to this issue of support. This study applies a generative dialogue framework to a series of dialogue sessions where ECTs engaged in conversations with one another about teaching and learning. The ECTs in the study were asked about their perceptions of support before and after the sessions, and then were interviewed after the final generative dialogue session. These teachers spoke about the challenges they face as ECTs, and they explained the importance of dialogue, collegial relationships, professional learning, and personal growth as it related to the implementation of generative dialogue. Finally, a series of next steps were identified in continuing this work with generative dialogue
