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Article
Publication date: 1 August 2003

Xu Rui, Cui Ping‐yuan, Xu Xiao‐fei and Cui Hu‐tao

Because of indeterminateness of the environment and delay of the communication, deep space spacecraft is required to be autonomous. Planning technology is studied in order…

Abstract

Because of indeterminateness of the environment and delay of the communication, deep space spacecraft is required to be autonomous. Planning technology is studied in order to realize the spacecraft autonomy. First, a multi‐agent planning system (MAPS) based on temporal constraint satisfaction is proposed for concurrency and distribution of spacecraft system. Second, timeline concept is used to describe simultaneous activity, continue time, resource and temporal constraints. Third, for every planning agent in the MAPS, its layered architecture is designed and planning algorithm based on the temporal constraint satisfaction is given in detail. Finally, taking some key subsystems of deep space explorer as an example, the prototype system of MAPS is implemented. The results show that with the communication and cooperation of the planning agents, the MAPS is able to produce complete plan for explorer mission quickly under the complex constraints of time and resource.

Details

Aircraft Engineering and Aerospace Technology, vol. 75 no. 4
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 16 August 2019

Lichen Gu, Rui Xu and Nan Wang

The purpose of this paper is to identify the energy losses factors during the hydro-mechanical conversion process at high pressure via a novel reduced order dynamic model.

Abstract

Purpose

The purpose of this paper is to identify the energy losses factors during the hydro-mechanical conversion process at high pressure via a novel reduced order dynamic model.

Design/methodology/approach

A novel reduced order dynamic model of the axial piston motor was proposed, which provides an explicit insight to the compression flow losses and the Coulomb friction losses. A fully coupled dynamic model of the piston motor was obtained based on the array bond graph method. And then, a reduced order model was obtained by the composition analysis of flow and torque of the axial piston motor. After that, the energy losses estimation model was presented to predict the energy loss of the piston motor under a wide range of working conditions. The model was verified by comparing the experimental and simulation results.

Findings

The simulation result indicates that the flow loss caused by oil compression accounts for 59 per cent of the total flow loss, and the Coulomb friction torque accounts for 40 per cent of the total torque loss under a specific working condition. The compression flow loss and Coulomb friction torque are the major factors that lead to the aggravation of energy loss under extreme working conditions of the piston motor.

Originality/value

At high-pressure condition, the compression flow losses due to fluid compressibility cannot be neglected, and the hydro-mechanical losses in varies friction pairs should involve Coulomb friction losses. Flow and torque loss analytical expression in the model involve the design and control parameters of the piston equipment, which can realize the parameter optimization of the piston equipment for the purpose of energy-saving.

Details

Industrial Lubrication and Tribology, vol. 72 no. 5
Type: Research Article
ISSN: 0036-8792

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Case study
Publication date: 1 April 2016

Xu Xiaojun, Hong Rui, Xu Weili, Yang Huaying and Jia Xizi

Against the backdrop of IBM Personal Computer Business's acquisition by Lenovo Group, this case introduces the remodeling process of Lenovo's HR organization and…

Abstract

Against the backdrop of IBM Personal Computer Business's acquisition by Lenovo Group, this case introduces the remodeling process of Lenovo's HR organization and development team, during which the company's 5P principle, namely “Plan (think clearly before making promise), Perform (promise is to be fulfilled), Prioritize (company's interest is top priority), Practice (make progress every day in every year), Pioneering (venture any experiment to be a trailblazer), takes shape. After learning about Lenovo's recruitment of internationalized talents, cross-cultural coaches for senior leaders, cultural development in internationalization and risk aversion in international operations, we can understand what Lenovo's HR team does to avoid conflicts in corporate culture and ethnic culture in cross-border mergers and acquisitions and integration, and how to adjust and change the HR management system.

Details

Management School, Fudan University, vol. no.
Type: Case Study
ISSN: 2632-7635
Published by: Management School, Fudan University

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Article
Publication date: 4 March 2014

Jocelyn L.N. Wong

Studies in teacher research have seldom discussed the effects of writing publications and teachers’ views on it. This paper aims to examine how teachers in China regard…

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912

Abstract

Purpose

Studies in teacher research have seldom discussed the effects of writing publications and teachers’ views on it. This paper aims to examine how teachers in China regard the purpose of writing up research papers and its impact on their professional practice. It also investigates facilitating factors in preparing and writing publications.

Design/methodology/approach

This is a qualitative study which mainly analyses interview data gathered from 14 teachers, who have experience in writing publications, from three schools in Shanghai, China. Documentary analysis includes selected published journal papers and book chapters of the interviewees.

Findings

Findings show that teachers perceive producing publications as serving both an instrumental purpose of career advancement and a developmental purpose of enhancing their individual professional competency which in turn improves the quality of the teaching profession through knowledge transfer and knowledge transportation.

Research limitations/implications

Contributing factors to help teachers to write include the provision of systematic training courses for teachers and the development of network and research partners.

Originality/value

Findings of this study help school leaders and teacher educators better their understanding of improving the quality of practice of teachers through equipping them with a “stance of inquiry”. Findings suggest ways to provide relevant support to enhance the writing capacity of teachers. More importantly, a revision of the existing teacher promotion system may make the practice of writing publications of more direct value to teachers’ daily practice.

Details

International Journal of Educational Management, vol. 28 no. 3
Type: Research Article
ISSN: 0951-354X

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Article
Publication date: 1 February 2011

Rui Xu and Diane Sparks

Shang, (from which Qun evolved), came into being before Ku, and was used to cover the lower body. Combined with the upper garment Yi, Ku and Shang

Abstract

Shang, (from which Qun evolved), came into being before Ku, and was used to cover the lower body. Combined with the upper garment Yi, Ku and Shang constituted a complete outfit in the traditional Chinese clothing system. This article briefly describes the development and evolution of Chinese Ku. It postulates that the opening and closing rise of Ku, was a metaphor for the spirit and the cultivation of Chinese literati. Qun, as a kind of lower cover, was actually unable to cover the body completely. Ku, the Chinese trousers for protection of legs, covered the lower limbs, but was not adopted by the Chinese literati in ancient times. Therefore, half-openness of the skirt and half-closeness of the rise of Ku, metaphorically representing half fantasy and half reality, were combined to complete the covering. This system for covering the body with a clothing combination that was partly open (thus exposing parts of the body) reveals an interesting aspect of Chinese traditional culture. Contemporary designers may find unique inspiration through the study of Chinese traditional clothing systems, for current fashion designs that have rich historical significance.

Details

Research Journal of Textile and Apparel, vol. 15 no. 1
Type: Research Article
ISSN: 1560-6074

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Article
Publication date: 2 November 2015

Cheng Gao, Rui-Na Xu and Pei-Xue Jiang

Lattice Boltzmann method (LBM) is employed to explore friction factor of single-phase fluid flow through porous media and the effects of local porous structure including…

Abstract

Purpose

Lattice Boltzmann method (LBM) is employed to explore friction factor of single-phase fluid flow through porous media and the effects of local porous structure including geometry of grains in porous media and specific surface of porous media on two-phase flow dynamic behavior, phase distribution and relative permeability. The paper aims to discuss this issue.

Design/methodology/approach

The 3D single-phase LBM model and the 2D multi-component multi-phase Shan-Chen LBM model (S-C model) are developed for fluid flow through porous media. For the solid site, the bounce back scheme is used with non-slip boundary condition.

Findings

The predicted friction factor for single-phase fluid flow agrees well with experimental data and the well-known correlation. Compared with porous media with square grains, the two-phase fluids in porous media with circle grains are more connected and continuous, and consequently the relative permeability is higher. As for the factor of specific porous media surface, the relative permeability of wetting fluids varies a little in two systems with different specific surface areas. In addition, the relative permeability of non-wetting fluid decreases with the increasing of specific surface of porous media due to the large flow resistance.

Originality/value

Fluid-fluid interaction and fluid-solid interaction in the SC LBM model are presented, and schemes to obtain immiscible two-phase flow and different contact angles are discussed. Two-off mechanisms acting on the wetting fluids is proposed to illustrate the relative permeability of wetting fluids varies a little in two systems with different specific surface.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 25 no. 8
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 17 October 2008

Rui Xu and Donald C. Wunsch

The purpose of this paper is to provide a review of the issues related to cluster analysis, one of the most important and primitive activities of human beings, and of the…

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1664

Abstract

Purpose

The purpose of this paper is to provide a review of the issues related to cluster analysis, one of the most important and primitive activities of human beings, and of the advances made in recent years.

Design/methodology/approach

The paper investigates the clustering algorithms rooted in machine learning, computer science, statistics, and computational intelligence.

Findings

The paper reviews the basic issues of cluster analysis and discusses the recent advances of clustering algorithms in scalability, robustness, visualization, irregular cluster shape detection, and so on.

Originality/value

The paper presents a comprehensive and systematic survey of cluster analysis and emphasizes its recent efforts in order to meet the challenges caused by the glut of complicated data from a wide variety of communities.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 1 no. 4
Type: Research Article
ISSN: 1756-378X

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Book part
Publication date: 4 July 2019

Reyhan Can and Işın Dizdarlar

This study is concerned with markets operating in Turkey in the Istanbul Stock Exchange (BIST), which have been observed and studied in relation to herd behavior. During…

Abstract

This study is concerned with markets operating in Turkey in the Istanbul Stock Exchange (BIST), which have been observed and studied in relation to herd behavior. During the research part of the study, the existence of herd behavior was investigated with the help of the daily closing price data of the firms in BIST between January 2011 and December 2017. In the research section of the study, the authors used regression analysis. In the analysis, the authors used the index value of the BIST whole Index. The average value of the index value of BIST whole Index was taken. Then, according to this average, 1% percentile and 5% percentile were taken. In the periods in the 1% percentile (at the dates) the result was that herd behavior was present. The herd behavior was observed for the periods (for dates) included in the percentile of 1%. On the other hand, the results of the analysis for the 5% percentile show that the herd behavior is only seen in the upper extremes.

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Article
Publication date: 13 April 2012

Mohamed El‐Attar

Security is a vital requirement for software systems. Misuse case models allow system designers to inject security considerations within their designs early in the…

Abstract

Purpose

Security is a vital requirement for software systems. Misuse case models allow system designers to inject security considerations within their designs early in the development cycle rather than patching an end system with security mechanisms after it was developed. The notation and syntactical rules of misuse case models are relatively simple. However, misuse case modeling practitioners are highly vulnerable to modeling pitfalls, creating defective models that can have catastrophic effects downstream in the development cycle. This paper seeks to present a framework that unitizes antipatterns to help remedy defective misuse case models and poor modeling practices.

Design/methodology/approach

A repository of antipatterns was constructed and formatted to be machine‐readable whenever possible so that it can be utilized by the proposed framework. The feasibility of the proposed approach was then demonstrated using a real‐world misuse case model of an online bookstore system.

Findings

The results indicate that the overall quality and clarity of the bookstore misuse case model is improved by applying the proposed technique and framework.

Research limitations/implications

This research work presents a series of domain‐independent antipatterns. Users of this framework may be interested to develop domain‐dependent antipatterns to better suit their modeling and development needs.

Originality/value

The proposed approach will help misuse case modelers, especially novice ones, to improve the quality of their current models as well as future models.

Details

Business Process Management Journal, vol. 18 no. 2
Type: Research Article
ISSN: 1463-7154

Keywords

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Article
Publication date: 6 September 2011

Cui Hutao, Cheng Xiaojun, Xu Rui and Cui Pingyuan

The purpose of this paper is to propose an attitude control algorithm for spacecraft with geometric constraints.

Abstract

Purpose

The purpose of this paper is to propose an attitude control algorithm for spacecraft with geometric constraints.

Design/methodology/approach

The geometric constraint is reformulated as a quadratic form when quaternion is used as attitude parameter, then the constraint is proved to be nonconvex and is further transformed to a convex one. By designing a new constraint formulation to satisfy the real constraint in the predictive horizon, the attitude control problem is reshaped to a convex planning problem which is based on receding horizon control.

Findings

The proposed algorithm is more effective in handling geometric constraints than previous research which used single step planning control.

Practical implications

With novel improvements to current methods for steering spacecraft from one attitude to another with geometric constraints, great attitude maneuver path can be achieved to protect instruments and meanwhile satisfy mission requirements.

Originality/value

The attitude control algorithm in this paper is designed especially for the satisfaction of geometric constraints in the process of attitude maneuver of spacecraft. By the application of this algorithm, the security of certain optical instruments, which is critical in an autonomous system, can be further assured.

Details

Aircraft Engineering and Aerospace Technology, vol. 83 no. 5
Type: Research Article
ISSN: 0002-2667

Keywords

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