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Copyright of Scientific Chronicles / Epistimonika Chronika is the property of Tzaneio General Hospital and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Academia is the property of Library & Information Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recently, studies of squirrel-cage induction machines validate the idea that these machines follow the double-cage induction model; however, the manufacturers categorize these machines as single-cage machines. There are many references that use the squirrel-model for squirrel-cage machines, then machine parameters increase from 5 to 7. In the laboratory, parameter determination is performed to estimate 5 parameters; however, 7 parameters have to be determined. Also, the DC test is not an exact test and is used for approximate estimation. Therefore, locked rotor test equations are changed and an overload test is added. After measurements in the laboratory according to the equations of this paper, a MATLAB program is prepared and 7 parameters are determined in a loop until reaching the desired error. This paper demonstrates that laboratory squirrel-cage machines have to be corrected using the 7-parameter model. Furthermore, this paper shows the necessity of new laboratory test equations for squirrel-cage machines. Then a numerical method is used to determine the machine parameters. [ABSTRACT FROM AUTHOR]

In this paper, a decentralized energy management system is presented for intelligent microgrids with the presence of distributed resources using reinforcement learning. Due to the unpredictable nature of renewable energy resources, the variability of load consumption, and the nonlinear model of batteries, the design of a microgrid energy management system is associated with many challenges. In addition, centralized control structures in large-scale systems increase computational volume and complexity in control algorithms. In this paper, a fully decentralized multi-agent structure for a microgrid energy management system is proposed and the Markov decision process is used to model the stochastic behavior of agents in the microgrid. Electrical and thermal distributed resources, batteries, and consumers are considered intelligent and independent agents. They have the learning ability to explore and exploit the environment in a fully decentralized manner and achieve their optimal policies. The proposed method for hourly microgrid management is model-independent and based on learning. The method maximizes the profits of all manufacturers, minimizes consumer costs, and reduces the dependence of the microgrid on the maingrid. Finally, using real data from renewable energy sources and consumers, the accuracy of the proposed method in the Iranian electricity market is simulated and verified. [ABSTRACT FROM AUTHOR]

Magnetic Induction Tomography (MIT) is a promising modality for noninvasive imaging due to its contactless and nonionizing technology. In this imaging method, a primary magnetic field is applied by excitation coils to induce eddy currents in the material to be studied, and a secondary magnetic field is detected from these eddy currents using sensing coils. The image (spatial distribution of electrical conductivity) is then reconstructed using measurement data, the initial estimation of electrical conductivity, and the iterative solution of forward and inverse problems. The inverse problem can be solved using one-step linear, iterative nonlinear, and special methods. In general, the MIT inverse problem can be solved by Gauss-Newton iterative method with acceptable accuracy. In this paper, this algorithm is extended and the zoning technique is employed for the reduction of unknown coefficients. The simulation results obtained by the proposed method are compared with the real conductivity coefficients and the mean relative error rate is reduced to 24.22%. On the other hand, Gauss-Newton iterative method is extended for solving the inverse problem of the MIT, and sensitivity measurement matrices are extracted in different experimental and normalization conditions. [ABSTRACT FROM AUTHOR]

Islanding is one of the important challenges in power networks in the presence of distributed generation which is considered an undesirable incident due to the possibility of damage to operators, network equipment, and consumers. Therefore, it is necessary to quickly detect islanding and make a decision regarding the connection status of local distributed generation units in the network. In this paper, a passive islanding detection method is proposed using adaptive threshold-based instantaneous frequency droop characteristic. The proposed threshold limit is dynamically changed depending on under-studied conditions to discriminate the island from load changes, capacitor bank switching, motor start-up, and short circuit types. Two medium voltage networks of Cigre and 34-bus IEEE are used to evaluate the proposed method. The simulations are performed in Digsilent software and the proposed method is implemented in MATLAB software. The simulation results indicate that the island is correctly detected with appropriate accuracy in a short period of time from other disturbances in the presence of wind, solar and diesel types of distributed generations. [ABSTRACT FROM AUTHOR]

Copyright of Scientific Chronicles / Epistimonika Chronika is the property of Tzaneio General Hospital and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Academia is the property of Library & Information Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Academia is the property of Library & Information Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: The role of entrepreneurs and entrepreneurship in any economy's economic growth and development is evident. The literature argues that entrepreneurship is essential for the dynamism of the modern market economy and a greater entry rate of new businesses, which can foster competition and economic growth. Entrepreneurs are the engine of sustainable economic growth and innovation within an economy. Factors determining entrepreneurship can be financial, institutional, economic, and framework conditions. The literature treated human capital's effects on entrepreneurship in isolation, while in reality, its effects depend on access to financial capital, and the human capital's effects on entrepreneurship are contingent on financial development levels. The main objective of this paper is to investigate the impact of human capital on entrepreneurship, considering the role of financial development in selected factor-driven and innovation-driven economies. This paper re-explores the integrated findings in the literature regarding human capital's effects on entrepreneurial outcomes, aiming to broaden the analysis by focusing on the effects of higher education on entrepreneurship rates and the role of financial development. Methods: The sample consists of 17 countries, and the selected factor-driven (or transition from stage 1 to stage 2) countries, including Iran, Kazakhstan, India, Vietnam, Pakistan, Philippines, and Algeria, and innovation-driven ones, including the United States, Netherlands, France, Spain, Japan, Germany, Italy, Switzerland, and Sweden. Data were collected from the World Bank's World Development Indicators, the Worldwide Governance Indicators, International Financial Statistics, the International Monetary Fund, and the Global Entrepreneurship Monitor. For each category of countries, three models were estimated according to the three indicators of financial development separately and using tabular and consolidated data from 2012 to 2020. Results: the research results showed that in innovation-driven economies, the benefits of tertiary enrollment rates in entrepreneurship are high when the level of financial development is low. For factor-driven economies, the effect of tertiary enrollment rates in entrepreneurship is higher when levels of financial development are high. In other words, in these countries, financial development and human capital complement each other to strengthen entrepreneurship. Conclusion: The literature exploring education's effects on entrepreneurship levels revealed integrated results. The analysis results of the present study suggested one main reason: literature ignored the complex and significant interaction between human capital and financial capital. In innovation-driven economies, without adequate financial capital, countries benefit greatly from a rise in tertiary enrollment rates as the educated cohort receives skills in grabbing entrepreneurial opportunities. Thus, a boost in the entrepreneurship rate can be observed. However, once financial development improves for countries, the boost in entrepreneurship provided by human capital is reduced. Quite simply, the impact of higher education on entrepreneurship rates is strongest in countries with the lowest levels of capital availability and financial development. In contrast, in factor-driven economies, the results indicate that the impact of human capital on entrepreneurship will increase with the expansion of financial development. In other words, higher levels of human capital for an individual lead to expanded job opportunities within existing companies and businesses, increasing the opportunity cost for the individual to become an entrepreneur. The effect of higher education on entrepreneurship rates becomes more positive and stronger in factor-driven economies with the highest levels of capital availability and financial development. Finally, considering the non-linear effects of human capital on entrepreneurship, the results showed that while the substitutability relationship between human and financial capital exists at all levels of tertiary enrollment rates in innovation-driven economies, in factor-driven economies, a supplementary effect was observed between financial development and tertiary enrollment rates. [ABSTRACT FROM AUTHOR]

Copyright of Byzantion Nea Hellás is the property of Universidad de Chile, Facultad de Filosofia y Humanidades and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Scientific Chronicles / Epistimonika Chronika is the property of Tzaneio General Hospital and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Academia is the property of Library & Information Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Academia is the property of Library & Information Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Academia is the property of Library & Information Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper consists of three case studies regarding the stage topography of Aeschylus’ Seven against Thebes. These case studies revolve around the following questions: (i) whether the Theban acropolis on which the play is set would require the use of an elevated structure such as a raised stage; (ii) how the characters’ entrances and exits are semiotised, and whether a semiotically active skēnē can be extrapolated from the script; and (iii) what indications are provided by the script on the arrangement of the gods’ statues in the acting area. With regard to (i), it is argued that the hypothesis of a raised stage is not warranted by the text of Septem. With regard to (ii), the paper attempts to reconstruct the play’s imaginary topography, especially in relation to the semiotic function of the parodoi, and argues that Septem requires no theatrically functional skēnē. Finally, with regard to (iii), the paper advocates a circular arrangement of the gods’ statues around the periphery of the orchestra. Discussion of these case studies is informed throughout by an awareness of the methodological problems and limitations associated with any attempt to reconstruct the visual aspect of early Greek theatre; these are brief ly surveyed in an introductory section. The paper also offers tentative suggestions for control mechanisms which may mitigate the effect of the aforementioned methodological limitations. [ABSTRACT FROM AUTHOR]

The commutation torque ripple adversely affects the performance of the six-phase inverter of the BLDC motor with trapezoidal back EMF and creates vibration and noise for industrial applications. In this paper, the motor model is obtained in non-commutation times and during the commutation period, and according to that, a suitable method to reduce the torque ripple, by equalizing the slope of the current disconnected from the motor and the slope of the current connected to the motor during commutation, is presented. At low speeds, torque ripple is reduced using predictive pulse width modulation technique. With this method, the duty cycle of the switch involved in the commutation is predicted and applied to the switch during the commutation intervals. At high speeds, this reduction is done using quasi z-source converter and selector circuit. The quasi z-source converter and the selector circuit increase the input voltage of the inverter during commutation intervals and increase its value to four times the back EMF voltage of the motor, thus reducing the torque ripple at high speeds. The theoretical and analytical results are verified using the simulations performed in the PLECS software. [ABSTRACT FROM AUTHOR]

In this paper, a three-level framework is proposed to determine the optimal scheduling of a Multi-Area Active Distribution Network in the presence of inter-area Soft Open Points (SOPs). In this framework, the uncertainty of renewable generation and forecasted demand is modeled using information gap decision theory in a risk-averse manner. Coordinated scheduling of Controllable Distributed Generators (CDGs) and SOPs, inter-area energy exchanges and energy trading with upstream network considering the uncertainties are the contribution of the presented method. To improve the computational efficiency and to achieve the optimal solution, the scheduling problem is modeled as a second-order conic programming in which the operational and security constraints of the network, CDG limitations, and operational constraints of SOPs are accurately modeled and the problem is solved by executing CPLEX solver in MATLAB environment. A case study on IEEE 33-bus test system showcases the superiority of the proposed model compared to meta-heuristic algorithms such as particle swarm optimization, genetic algorithm, and gravitational search algorithm. [ABSTRACT FROM AUTHOR]

Low-frequency noise modeling and estimation is a critical issue in the design of analog and digital circuits, especially for short-channel CMOS technologies. The conventional noise models do not fit the experimental results adequately at frequencies close to DC for amplifiers and close to the carrier frequency for oscillators. Furthermore, measuring this noise necessitates the use of specialized and expensive equipment. In this paper, the bound of carrier trapping and releasing are extracted while examining the characteristics of low-frequency noise using the EMD method, and an innovative model based on carrier number fluctuations is proposed. The method introduces a low-cost measurement system for low=frequency noise. The performance accuracy of this measurement system and the proposed model is evaluated and compared with conventional noise modeling methods. The evaluation results demonstrate the success of the proposed measurement setup and model in estimating near-DC noise. [ABSTRACT FROM AUTHOR]

The presence of electric vehicle technology in distribution networks as controllable resources provides advantages such as voltage regulation, power peaking, and loss reduction. This technology has a positive effect on the performance of the distribution network, but the simultaneous presence of electric vehicles and distributed generation sources requires optimal planning because the lack of access to an application reduces the life of these technologies and can cause blackouts in the power network. Therefore, in this study, the dynamic reconfiguration of the distribution network in the simultaneous presence of distributed generation sources and electric vehicles is proposed. Also, the time-of-use mechanism has been proposed as one of the demand response applications to improve the power consumption of subscribers. The objective functions in this study include the reduction of energy loss, operational cost and energy not supplied as the objective function of reliability. In general, the optimization problem of distribution network reconfiguration is complex and non-convex. Also, considering the effect of distributed generation units and electric vehicles makes the problem more complicated than before. Therefore, finding a practical method to solve the optimization problem is one of the main challenges of this paper. For this purpose, a novel hybrid algorithm based on a combination of an improved particle swarm optimization-artificial bee colony is presented to overcome the complexities of the optimization problem. The proposed method has [ABSTRACT FROM AUTHOR]

Traditionally, photovoltaic power plants use Maximum Power Point Tracking (MPPT) algorithms to produce maximum electrical energy. However, with the increase of grid-installed photovoltaic power plants, power system operators have faced new challenges such as overload, overvoltage, and proper performance during grid voltage disturbances. As a result, network standards and codes have been updated in the direction of photovoltaic systems that are more controllable and compatible with the network. To provide various grid support functions, such as frequency response and voltage support, the Constant Power Generation (CPG) control algorithm is established by grid codes. For this purpose, MPPT algorithms have been replaced by flexible power point tracking (FPPT) algorithms. This paper proposes an algorithm to control photovoltaic systems based on a multi-level cascaded full-bridge (CHB) inverter to achieve constant power generation control by the FPPT method. The required power reference is distributed among the sub-modules of the CHB converter according to the available power of each sub-module in such a way that, as much as possible, each sub-module is loaded equally. Then, the FPPT algorithm with an adaptive voltage step is used to set the power of each submodule in its reference value. The voltage step is calculated adaptively based on the observed condition (transient or steady state) so that the tracking performance has fast dynamics. The effectiveness of the proposed algorithm is evaluated by simulating a 500-kW photovoltaic system directly connected to a 4.7 kV grid. [ABSTRACT FROM AUTHOR]

Islanding is one of the important challenges in power networks in the presence of distributed generation which is considered an undesirable incident due to the possibility of damage to operators, network equipment, and consumers. Therefore, it is necessary to quickly detect islanding and make a decision regarding the connection status of local distributed generation units in the network. In this paper, a passive islanding detection method is proposed using adaptive threshold-based instantaneous frequency droop characteristic. The proposed threshold limit is dynamically changed depending on under-studied conditions to discriminate the island from load changes, capacitor bank switching, motor start-up, and short circuit types. Two medium voltage networks of Cigre and 34-bus IEEE are used to evaluate the proposed method. The simulations are performed in Digsilent software and the proposed method is implemented in MATLAB software. The simulation results indicate that the island is correctly detected with appropriate accuracy in a short period of time from other disturbances in the presence of wind, solar and diesel types of distributed generations. [ABSTRACT FROM AUTHOR]

The present paper examines the dramatic significance and the theatrical function of babies and baby-items in Euripides’ plays in which they appear as concrete stage props. More specifically, this paper examines the element of realism inherent in this sort of material (οἰκεῖα πράγματα), which bears strongly on the everyday and the domestic, and further examines the ways in which realism is transformed in order to serve purely dramatic purposes. In one section, the discussion focuses on the on-stage presence of the baby Opheltes in the opening scenes of Hypsipyle and on the κρόταλα with which the protagonist tries to amuse or comfort him while delivering her monody. In another section, the discussion focuses on Ion’s birth tokens in the climactic recognition-scene of Ion. On both occasions, special emphasis is laid on the subtle ways in which the poet manipulates realism in order to reinforce pathos and generate empathetic effect. [ABSTRACT FROM AUTHOR]

Copyright of Scientific Chronicles / Epistimonika Chronika is the property of Tzaneio General Hospital and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Scientific Chronicles / Epistimonika Chronika is the property of Tzaneio General Hospital and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: The irreplaceable role of cities in economic, cultural and political development of countries, their challenges and problems and the difficulty of their management has resulted in an increasing significance of theories, experiences and strategies concerning city transformation. In the relevant literature, numerous concepts and approaches try to offer images of future of cities. One of these concepts is smart cities. Also, participative foresight can play a role in creating future images of cities. This study seeks to offer recommendations on how to create local and brand-new images of futures of cities in Iran and improve the quality of urban foresight practices. Method: A thick report of an event ethnography has been given from a foresight workshop conducted in Isfahan municipality about futures of Isfahan, 1420, based on observations, field notes by ethnographers and the theoretical interpretation of them. Findings: Utilization of participative deliberation and foresight techniques and event ethnography to create images of future is the innovative dimension of this paper. Conclusion: Adding materiality to future, deconstruction of technological utopianism discourse, conceptualization of foresight as a social capacity deriving from civic epistemologies and agonism, moving beyond used futures, and creation of neologisms can improve urban foresight practices. [ABSTRACT FROM AUTHOR]

Copyright of Scientific Chronicles / Epistimonika Chronika is the property of Tzaneio General Hospital and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Scientific Chronicles / Epistimonika Chronika is the property of Tzaneio General Hospital and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

After a short historical account of the reception of Aristophanes in early twentieth-century Greece, this paper explores analogies with and inf luences from Aristophanic comedy in Kostas Karyotakis’ work. It is argued that his poem Mikri asymphonia eis A meizon and the short story Oneiropolos draw upon Frogs and Clouds, respectively, in a way suggesting Karyotakis’ modernist reading of Aristophanes, against the trend of his time to perceive the ancient dramatist as an author of pornographic revues. [ABSTRACT FROM AUTHOR]

Although the ‘theatre of the three great tragedians’ has attracted more scholarly attention than any other theatrical structure, and justifiably so, due primarily to the lack of firm archaeological evidence, the arguments presented in the research are often utterly contradictory. Utilizing the recent unprecedented partial discovery of traces left by the much-vaunted ikria bench posts, in conjunction with a re-examination of the monument and the literary and epigraphic evidence pertaining to it, this paper seeks to reconstruct the morphological and functional features of the theatre of Dionysus in the era of the three great tragedians, and the changes made to it between the late 6th century and ca. 350 bc. More specifically, it is shown that this innovative theatre was built as a permanent structure ab initio, while matters pertaining to the monumentality of the Periclean theatre are explored, along with the attempt to start building a stone theatre whose design was integrated with that of the Odeum of Pericles (by Ictinus?), the evidence of innovative architectural solutions, and — centrally — morphological and functional issues pertaining to the much-discussed ‘tragic stage’. [ABSTRACT FROM AUTHOR]

Copyright of Issues in Ethnology Anthropology is the property of Issues in Ethnology Anthropology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)