Search results

The purpose of this paper is to address the problem of control in a typical chaotic power system. Chaotic oscillations cannot only extremely endanger the stabilization of the power system but they can also not be controlled by adding the traditional controllers. So, the sliding mode control based on a fuzzy supervisor can sufficiently ensure perfect tracking and controlling in the presence of uncertainties. Closed-loop stability is proved using the Lyapunov stability theory. The simulation results show the effectiveness of the proposed method in damping chaotic oscillations of the power system, eliminating control signal chattering and also show less control effort in comparison with the methods considered in previous literatures.

The sliding mode control based on a fuzzy supervisor can sufficiently ensure perfect tracking and controlling in the presence of uncertainties. Closed-loop stability is proved using the Lyapunov stability theory.

Closed-loop stability is proved using the Lyapunov stability theory. The simulation results show the effectiveness of the proposed method in damping chaotic oscillations of power system, eliminating control signal chattering and also less control effort in comparison with the methods considered in previous literatures.

Main contributions of the paper are as follows: the chaotic behavior of power systems with two uncertainty parameters and tracking reference signal for the control of generator angle and the controller signal are discussed; designing sliding mode control based on a fuzzy supervisor in order to practically implement for the first time; while the generator speed is constant, the proposed controller will enable the power system to go in any desired trajectory for generator angle at first time; stability of the closed-loop sliding mode control based on the fuzzy supervisor system is proved using the Lyapunov stability theory; simulation of the proposed controller shows that the chattering is low control signal.

Business is about building relationships and hence relationship building is becoming increasingly important for cross‐cultural management. Current research findings in this area have mainly focused on relationship marketing or on cultural dimensions of business relationships. This preliminary study attempts to break the boundary and aims to explore relationship building from a culture‐specific perspective while in corporating a social constructivist dimension. Specifically, it compares relationship building across four cultures including European, New Zealand, Chinese, Indian and South African cultures. The research method is interpretive, based on an analysis of interview results with business executives from the four target cultures.

E‐commerce plays an important role in today’s business environment, and that role will continue to grow each year. eMarketer predicts that by “2004, world wide e‐commerce revenues are expected to total USD 2.7 trillion”. E‐commerce continues to grow in the United States. “The Census Bureau of the Department of Commerce announced today that the estimate of U.S. retail e‐commerce sales for the first quarter of 2004, not adjusted for seasonal, holiday, and trading‐day differences, was $15.5 billion, an increase of 28.1 per cent (±2.9 per cent) from the first quarter of 2003.” “According to a new study by RoperASW and AOL Time Warner, Europeans spent on average EUR430 on line between August and October 2002.” This compares with an average spend of EUR543 per head in the US over the same period.

The purpose of this paper is to present a novel nitrile butadiene rubber (NBR) packaging structure, which can solve the problems of the low sensitivity, narrow frequency band and fluctuating frequency response curve of the MEMS bionic vector hydrophone.

A 0.05-mm-thick NBR sound-transparent cap was designed by theoretical analysis and simulation to reduce the signal attenuation caused by the packaging structure, and the frequency band of the hydrophone has been extended to 4 kHz. In this work, the vector hydrophone was fabricated by the MEMS technology and packaged with the NBR sound-transparent cap. The performance indicators were calibrated in the National Defence Underwater Acoustics Calibration Laboratory of China.

The results show that the sensitivity of NBR-packaged hydrophone reaches −170 dB (±2 dB), and the difference is less than 1 dB compared to bare chip. And the frequency band is 50 Hz-4 kHz. The hydrophone also has good directional pattern in the form of an 8-shape, and the pressure-resisting ability is more than 2 MPa.

The packaging structure significantly increases the sensitivity of the hydrophone and broadens the frequency band, providing a new method in the packaging design for MEMS hydrophone.

In recent years, numerous banks have introduced live chat systems to their mobile banking (m-banking) applications to help customers address problems that arise while using m-banking. However, few researchers have investigated bank customers' perceptions of live chat in the context of m-banking, known as mobile chat. The present study attempts to fill this research gap and identify potential factors affecting bank customers' intention and attitude toward using mobile chat from the perspective of functional and expected advantages.

A research model was developed integrating three technological characteristics of mobile chat (mobility, reachability and convenience) identified from the mobile service and self-service technology literature with user beliefs involving performance expectancy, effort expectancy and facilitating conditions specified by the unified theory of acceptance and use of technology. The proposed model was evaluated using data collected from a field survey of 268 customers with experience in Internet or m-banking at an international bank in Taiwan. The mediating effects of attitude on the relationship between intention and its predictors were also measured.

The results suggest that reachability and convenience influence performance expectancy whereas effort expectancy is affected by all the technological characteristics. Additionally, customers' intention is determined by attitude, effort expectancy and facilitating conditions whereas their attitude depends on the three constructs of user beliefs.

The development of user behavioral research in intelligent customer engagement is lacking in the m-banking literature. This study sheds light on Internet banking and m-banking customers' viewpoints and the salient determinants of their intention and attitude toward using mobile chat. Therefore, the findings allow a broader understanding of customer engagement applications in the banking sector.

The research findings would help banks not only better understand how to deploy useful mobile applications for improving the effectiveness of their mobile service development but also develop adequate mobile strategies to engage with customers more intelligently.

This research provides valuable insight into the relationship between the adoption of intelligent customer engagement tools and the improvement of customer support performance in the context of m-banking. Moreover, this study is among the first to identify the potential mobile technological factors that might affect bank customer expectations from mobile chat applications.

The purpose of this paper is to estimate Google search engine’s ranking function from a search engine optimization (SEO) perspective.

The paper proposed an estimation function that defines the query match score of a search result as the weighted sum of scores from a limited set of factors. The search results for a query are re-ranked according to the query match scores. The effectiveness was measured by comparing the new ranks with the original ranks of search results.

The proposed method achieved the best SEO effectiveness when using the top 20 search results for a query. The empirical results reveal that PageRank (PR) is the dominant factor in Google ranking function. The title follows as the second most important, and the snippet and the URL have roughly equal importance with variations among queries.

This study considered a limited set of ranking factors. The empirical results reveal that SEO effectiveness can be assessed by a simple estimation of ranking function even when the ranks of the new and original result sets are quite dissimilar.

The findings indicate that web marketers should pay particular attention to a webpage’s PR, and then place the keyword in URL, the page title, and snippet.

There have been ongoing concerns about how to formulate a simple strategy that can help a website get ranked higher in search engines. This study provides web marketers much needed empirical evidence about a simple way to foresee the ranking success of an SEO effort.

European Union (EU) indicators on poverty and social exclusion employ only two child breakdowns: the proportion of children living in households with incomes below 60% of the national median using the modified OECD equivalence scale and the proportion of children living in workless households. The UK also uses these indicators in the Opportunities for All series. This article first develops a new indicator of child poverty based on income, subjective and deprivation indicators which may be more reliable than income alone. It then explores the extent to which income poverty and worklessness represent international variation in child well‐being using an index that we have developed. The conclusions are that: (1) relative income poverty and worklessness are poor indicators of child well‐being, especially for some of the new EU countries; (2) deprivation has a stronger association with overall well‐being than relative income poverty or worklessness; (3) there are a number of other single indicators of child well‐being that could be used as proxies for overall child well‐being; and (4) The EU (and the UK) could easily develop its own index of child well‐being.

This paper proposes a framework for director evaluation in the context of Chinese state-owned enterprises (SOEs), taking into account the influences of traditional and modern Chinese ideologies.

Following the Delphi method, a series of semi-structured interviews were conducted with Chinese SOE directors.

The framework used has been validated by examining seven dimensions of virtue and four dimensions of competence functions in Chinese SOEs. Effective and representative characteristics of each dimension are identified through interviews.

First, through this research, indicators of virtue have been materialized and those of competence have been specified in a broader range. Second, this research provides advice for training of candidate directors whose experience were in private firms before they step in as SOE directors.

Carbon nanotubes (CNTs) with exceptional mechanical, thermal and electrical properties are considered to be ideal for reinforcing high-performance structures. The interfacial stresses between the CNTs and surrounding matrix are important phenomena which critically govern the mechanical properties of CNTs-reinforced nanocomposites. A number of methods have been proposed to investigate the stress transfer across the CNT/matrix interface, such as experimental measurement and molecular dynamics (MDs). Experimental tests are difficulty and expensive. MDs simulations, on the other hand, are computationally inefficient. The purpose of this paper is to present a reasonably simplified model. Incorporating the simplified model, the analytical expressions of the interface stresses including the shear stress and longitudinal normal stress are obtained.

The analytical model consists of two concentric cylinders, namely a single-walled carbon nanotube (SWCNT) cylinder and a matrix cylinder, as the representative volume element (RVE). The interfacial stress analysis is performed using the shear lag model for the axisymmetric RVE. Analytical solutions for the normal stresses in the SWCNT and matrix, and the interfacial shear stress across the SWCNT/matrix interface are obtained. The proposed model has a great ability to theoretical prediction of the stress transfer between the matrix and CNTs.

In order to demonstrate the simulation capabilities of the proposed model, parametric studies are conducted to investigate the effects of the volume fraction of SWCNT and matrix modulus on the stress transfer. The axial stress in the matrix is decreasing with the increase of the volume fraction and decrease of the matrix modulus. As a result of more loads can be transferred to the SWCNT for a large volume fraction and small matrix modulus. These results show that using a large volume fraction and a small matrix modulus improves the efficiency of the stress transfer from the matrix to the CNTs.

A simple but accurate model using a simplified 2D RVE for characterizing the stress transfer in CNT-reinforced nanocomposites is presented. The predictions from the current method compare favourably with those by existing experimental, analytical and computational studies. The simple and explicit expressions of the interfacial stresses provide valuable analysis tools accessible to practical users.