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Article

Ruan Li

The paper aims to study the effects of the combination of synchronous Web-based teaching with visually creative teaching on art students’ creativity. The twenty-first…

Abstract

Purpose

The paper aims to study the effects of the combination of synchronous Web-based teaching with visually creative teaching on art students’ creativity. The twenty-first century is the society of information technology and knowledge-based economy. To cope with the information society, teaching methods would be changed. Traditional chalk and talk can no longer adapt to the changing society. In addition to passing down the tradition, new ideas should also be introduced. In the informational age, the internet becomes an essential living element and synchronous Web-based teaching breaks through the obstacle of space, provides instant and multiple communication channels and creates alternative creativity learning environment.

Design/methodology/approach

With experimental design, totally, 208 students in Fujian University of Technology, as the research objects, were led to a 15-week (3 hours per week for total 45 hours) experimental teaching. The study uses analysis of variance for discussing the effect of synchronous Web-based teaching on art students’ creativity and further understanding the effect of the combination of synchronous Web-based teaching with visually creative teaching on art students’ creativity.

Findings

The research results show significant effects of synchronous Web-based teaching on creativity, visually creative teaching on creativity and the combination of synchronous Web-based teaching with visually creative teaching on the promotion of creativity.

Research limitations/implications

First, the sample size taken in this study was not large enough to fully reflect the results of the study. The survey sample didn’t cover all the major cities in China, which had a small coverage and couldn’t reflect the research situation of the whole country. Second, the evaluation criteria for artistic students’ creativity were too broad. More specific evaluation rules should be set and the creativity standards should be graded to better guide the implementation of art courses and the cultivation of students’ creativity.

Practical implications

The synchronous Web-based learning environment provides favorable individual thinking space to effectively reduce disturbance among classmates. Synchronous Web-based teaching shares sound, pictures and even films with each other to enrich the learning media. What is more, teachers would be more convenient and fast to deal with materials or handouts or rapidly updating materials and avoiding the loss of handouts.

Originality/value

This paper studied the effects of the combination of synchronous Web-based teaching with visually creative teaching on art students’ creativity, which was a meaningful and innovative topic. And this study can provide more enlightenment and reference for future education.

Details

The Electronic Library, vol. 37 no. 5
Type: Research Article
ISSN: 0264-0473

Keywords

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Article

Silvio John Camilleri and Christopher J. Green

– The main objective of this study is to obtain new empirical evidence on non-synchronous trading effects through modelling the predictability of market indices.

Abstract

Purpose

The main objective of this study is to obtain new empirical evidence on non-synchronous trading effects through modelling the predictability of market indices.

Design/methodology/approach

The authors test for lead-lag effects between the Indian Nifty and Nifty Junior indices using Pesaran–Timmermann tests and Granger-Causality. Then, a simple test on overnight returns is proposed to infer whether the observed predictability is mainly attributable to non-synchronous trading or some form of inefficiency.

Findings

The evidence suggests that non-synchronous trading is a better explanation for the observed predictability in the Indian Stock Market.

Research limitations/implications

The indication that non-synchronous trading effects become more pronounced in high-frequency data suggests that prior studies using daily data may underestimate the impacts of non-synchronicity.

Originality/value

The originality of the paper rests on various important contributions: overnight returns is looked at to infer whether predictability is more attributable to non-synchronous trading or to some form of inefficiency; the impacts of non-synchronicity are investigated in terms of lead-lag effects rather than serial correlation; and high-frequency data is used which gauges the impacts of non-synchronicity during less active parts of the trading day.

Details

Studies in Economics and Finance, vol. 31 no. 4
Type: Research Article
ISSN: 1086-7376

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Article

Tarik Abdulahovic, Sercan Teleke, Torbjorn Thiringer and Jan Svensson

The purpose of this paper is to investigate the influence of time steps, integration methods, and saturation modeling on the accuracy of the synchronous machine model…

Abstract

Purpose

The purpose of this paper is to investigate the influence of time steps, integration methods, and saturation modeling on the accuracy of the synchronous machine model. This model is compared with the PSCAD built‐in synchronous machine model in order to compare the accuracy of one of the most used synchronous machine models in a commercially available software versus a well‐documented and widely accepted state‐space synchronous machine model.

Design/methodology/approach

In the paper, a synchronous condenser with the saturation phenomenon is modeled using state‐space equations in the rotating dq‐reference frame and is implemented both in Matlab/Simulink and PSCAD. Integration methods of up to the fifth order are implemented for increased accuracy. The saturation modeling includes modeling of the saturation in both d‐ and q‐axis. A steady‐state and dynamic performance comparison towards the built‐in PSCAD synchronous machine model is performed. The saturation modeling does not include the saturation of the leakage fluxes.

Findings

When the forward Euler method is used, in order to obtain less than 5 percent error, the time step should not exceed 5 μs. The third‐order Runge‐Kutta method is the preferred choice and it provides desired accuracy when the time step is equal or smaller than 1,000 μs. The built‐in PSCAD model satisfies the error criteria for time steps smaller than 300 μs. A small discrepancy of 2 percent is found during the steady‐state test.

Originality/value

The paper presents the performance of the higher order integration methods in an EMTP‐type software environment where the trapezoidal integration method is most often used. It provides a good guide for building an owner‐defined model. A comparison of a dynamic performance between the publicly documented state‐space and a synchronous machine models commonly used for power system transient studies is presented.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 29 no. 3
Type: Research Article
ISSN: 0332-1649

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Article

Bolanle A. Olaniran

The increased pressure to incorporate communication technologies into learning environments has intensified the attention given to the role of computer‐mediated…

Abstract

Purpose

The increased pressure to incorporate communication technologies into learning environments has intensified the attention given to the role of computer‐mediated communication (CMC) in academic settings. However, the issue of how and why these technologies, especially synchronous CMC applications, has been given less attention in pedagogical literature. This paper aims to address this problem.

Design/methodology/approach

The paper provides issues for consideration in the deployment of synchronous CMC in educational settings.

Findings

Shows that there are differences in asynchronous and synchronous CMC with related issues of productivity of student learning and control.

Originality/value

This paper outlines advantages and disadvantages of using synchronous CMC in education while offering practical guides.

Details

Campus-Wide Information Systems, vol. 23 no. 3
Type: Research Article
ISSN: 1065-0741

Keywords

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Article

Josh DeSantis, Ryan Boyd, Kyle Marks, Jake Putsch and Terrance Shepler

Successful technology integration into the teaching of social studies is imperative in the twenty-first century classroom. This study sought to answer the following…

Abstract

Purpose

Successful technology integration into the teaching of social studies is imperative in the twenty-first century classroom. This study sought to answer the following questions: do synchronous and asynchronous technology integration increase a student’s understanding of social studies content? Are synchronous technology-integrated social studies lessons more effective than asynchronous technology-integrated social studies lessons? How do students perceive the effectiveness of a synchronous technology-integrated lesson vs the effectiveness of an asynchronous technology-integrated lesson? The paper aims to discuss these issues.

Design/methodology/approach

This paper presents the results of a quasi-experimental research project comparing the learning outcomes of students who participated in synchronous and asynchronous technology-augmented lessons.

Findings

The results of this study found that synchronous and asynchronous technology-enhanced lessons are both viable pedagogies for increasing a student’s understanding of social studies content. The results also yielded no statistical significance between the effectiveness of the synchronous instruction vs asynchronous instruction. However, a statistical significance exists when analyzing a student’s perception of their own learning. Students participating in synchronous technology-integrated instruction reported a higher confidence in the lesson’s ability to teach them, when compared to that of the asynchronous population.

Originality/value

By continuing to seek new ways to integrate technology effectively into classrooms, social studies teachers can design lessons more effectively to meet the needs of today’s social studies students. The need to understand the learning outcomes of various technology-integrated approaches will continue to grow as more technologies become available to social studies teachers.

Details

Social Studies Research and Practice, vol. 12 no. 3
Type: Research Article
ISSN: 1933-5415

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Article

Mohamed Arbi Khlifi and Habib Rehaoulia

When magnetic saturation in ac machines is evolved, the theory of main flux saturation in d-q axes remains the best. Because of its simplicity, it is the most used in…

Abstract

Purpose

When magnetic saturation in ac machines is evolved, the theory of main flux saturation in d-q axes remains the best. Because of its simplicity, it is the most used in either motoring or generating mode for synchronous or asynchronous machines. Although, it is considered as a global way of introducing the iron saturation, compared to other methods, today, its fidelity has no contest in predicting complex ac machine operations. For this purpose, the aims of this paper consists of modeling these machines whatever the state-space variables values are taking into account the magnetic saturation. Two unified procedures are proposed. The first one deals with a common approach to establishing a complete and detailed model synthesis in d-q axes. The second also presents a unified approach to introducing magnetic saturation of the iron core in the characteristic equations. The analysis takes the salient pole synchronous machine as a general case of study. Then the approaches are extended to undamped and smooth air gap synchronous machines as well as induction machines. The paper aims to discuss these issues.

Design/methodology/approach

The present paper, which is a first part of a work under study dealing with a unified method to derive multiple models of saturated ac machines, is intended to the description of an alternative method and its application for induction and synchronous machines. It mainly consists of the following parts: first, after writing the stator and rotor space vector d-q equations, the number of possible models is immediately discussed. By considering the currents and fluxes as state-space variables, 14 models are obtained for AC induction machine (IM and SM). They are classified into three families, current (three), flux (three) and mixed models (eight). Second, in order to easily introduce the magnetic saturation in the 14 developed models, a method is presented. It consists of just elaborating the model with the winding currents as state variables, then deriving all the other models from it. Third, to emphasize the influence of the presence of magnetic saturation, in each model, each inductance along the d and q axes is written with a fundamental expression which exists with or without saturation and an additional one due purely to saturation. Hence the additional terms can be studied and quantified in an easy way or simply removed when linear case is assumed. Fourth, adopting such strategy to write the different coefficients of the models had led to the definition of common saturation factors. In turn, the definition of common saturation factors had allowed the definition of different groups of models within each family. Fifth, an alternative to evaluate the static and dynamic saturation coefficients is also proposed. It is shown that by proper fitting of the experimental magnetizing curve, all saturation coefficients can be written only in terms of which is simply the magnitudes ratio of the magnetizing flux and current. Sixth, although the theory of the main flux saturation is now admitted, an investigation was carried out on a self-excited induction generator and the build-up of voltage and current phases of a standalone alternator, to prove the equivalence between the all developed models.

Findings

The number of models based on the state-space variables choice, of a saturated ac machine, is reviewed. A simple method consisting of elaborating just the winding currents model, with magnetic saturation and deriving all the other models from it, is presented. In this study special interest was particularly focussed on either novel models or existing models cited in the literature but cannot be obtained by other approaches. In all cases, if the differential equations of the machine are formulated in terms of a set of variables other than the winding currents, a noticeable reduction in the size of equations may be obtained and consequently less time computing. The approach seems to be able to derive any possible model whatever the state-space variables and the type of the ac machine and hence can be classified as a general approach.

Practical implications

The experiments of synchronous and induction machine transients prove the validity of the method.

Originality/value

By suitable choice of state-space characteristic vectors among the fluxes and the currents, a synthesis of AC machine models in d-q axes is established. To introduce magnetic saturation in each model, an approach-based uniquely on the elaboration of the winding currents model is exposed and applied. In addition, the analysis gives a detailed classification of all found models taking into account the state variables nature as well as the cross-coupling coefficient considered as a saturation factor. The study is completed with a simple alternative to evaluate all saturation factors by just calculating the static magnetizing inductance.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 35 no. 1
Type: Research Article
ISSN: 0332-1649

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Article

Huaishu Li, Yanhui Lai, Wu Qiang and Xiang Dong

In order to research the law of the low‐frequency power oscillation which often exists in the synchronous generator rectification system, the purpose of this paper is to…

Abstract

Purpose

In order to research the law of the low‐frequency power oscillation which often exists in the synchronous generator rectification system, the purpose of this paper is to study theoretical analysis and numerical calculation on the static stability of the system.

Design/methodology/approach

Different from the common three‐phase synchronous generator operating in large power networks, the stability of synchronous generator rectification systems is much more difficult to analyze because of its nonlinear loads. Some papers have analyzed the stability of the synchronous generator rectification system and presented different parameter conditions of system stability, but since factors that influence the system stability are complex, the essence of this kind of oscillation is not completely known yet. By considering rectification systems as an equivalent to DC circuits, the correct circuit model which is necessary to analyze the rectification systemic stability is set up, the changing law and relationship of various parameters under mini‐disturbances is analyzed, a linear differential equation about the DC‐side average current is derived, the stability of the synchronous generator rectification system is analyzed and deduced by using Hull criterion, all parameters influencing system stability are calculated and analyzed, and their ranges for a stable rectification system are given. Also, the reason why and how the parameters affect system stability is explained.

Findings

The operational stability of synchronous generator rectification systems is completely and correctly recognized.

Practical implications

The paper has a reference value for the design and safe operation of synchronous generator rectification systems.

Originality/value

The paper puts forward system stability criterion and gives a rational physical explanation about system stability.

Details

Kybernetes, vol. 40 no. 5/6
Type: Research Article
ISSN: 0368-492X

Keywords

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Article

Desmond Doran

The paper presents a case study of Ikeda Hover Ltd, a synchronous seat supplier to Nissan Manufacturing UK Ltd. The case study explores the differences between…

Abstract

The paper presents a case study of Ikeda Hover Ltd, a synchronous seat supplier to Nissan Manufacturing UK Ltd. The case study explores the differences between just‐in‐time (JIT) and synchronous supply from both the buyer and supplier perspective, as well as examining the importance of effective supply chain management, effective use of appropriate technologies and the importance of quality within the context of a synchronous buyer‐supplier relationship. The findings of this case study suggest that whilst synchronous supply results in notable benefits for both buyer and supplier the journey to achieving synchronicity is difficult and such a supply system may be limited to the supply of a small number of key components or high value component systems.

Details

European Business Review, vol. 13 no. 2
Type: Research Article
ISSN: 0955-534X

Keywords

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Article

Carmen Taran

While synchronous and asynchronous distance education options have fulfilled the promise to reduce travel costs and decrease the number of human resources necessary for…

Abstract

Purpose

While synchronous and asynchronous distance education options have fulfilled the promise to reduce travel costs and decrease the number of human resources necessary for training delivery, many corporations are faced with the need to produce learning even at a faster pace in order to gain and sustain competitive advantage. This means a paradigm shift in the distance education arena: in order to reduce the time to produce and deliver training, subject matter experts (SMEs) are asked to step up to the plate and assume additional roles in the instructional design process. This research addresses these issues.

Design/methodology/approach

This research, conducted within the training department of a large telecommunications company, focuses on enabling SMEs to teach online, using synchronous instructional methods and a rapid e‐learning approach.

Findings

Based on student performance records and satisfaction survey results, it was concluded that SMEs are able to reduce training development time, deliver workshops online and maintain acceptable quality of instruction. SMEs' training background did not impact student achievement or satisfaction. Practical implications for corporate training development related to synchronous online training are also included.

Originality/value

The originality of the paper resides in the fact that the guidelines that emerged from this research are a step forward towards the expansion of rapid e‐learning as it applies to synchronous online training and to helping SMEs to teach online.

Details

Campus-Wide Information Systems, vol. 23 no. 3
Type: Research Article
ISSN: 1065-0741

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Article

Mitchell Wing and Jacek F. Gieras

The increased use of permanent magnet synchronous motors in small to medium power applications has made it imperative that these motors' performance can be modelled…

Abstract

The increased use of permanent magnet synchronous motors in small to medium power applications has made it imperative that these motors' performance can be modelled successfully. The accuracy of calculating the synchronous reactances determines the success of the modelling technique. An analytical method and the finite element method are used to calculate the synchronous reactances of two prototype synchronous motors. The calculations are compared with measurement for both motors. The results show that the finite element method is more reliable in obtaining synchronous reactances than the analytical method for rotor designs that are very intricate, although both methods show reasonable accuracy.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 14 no. 4
Type: Research Article
ISSN: 0332-1649

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