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1 – 10 of over 1000
Article
Publication date: 14 June 2011

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 study…

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

Article
Publication date: 7 December 2022

Qing-Wen Zhang, Pin-Chao Liao, Mingxuan Liang and Albert P.C. Chan

Quality failures in grid infrastructure construction would cause large-scale collapses in power supply and additional expenditures by reworks and repairs. Learning from quality…

Abstract

Purpose

Quality failures in grid infrastructure construction would cause large-scale collapses in power supply and additional expenditures by reworks and repairs. Learning from quality failures (LFQF) extracts experience from previous quality events and converts them into preventive measures to reduce or eliminate future construction quality issues. This study aims to investigate the influence factors of LFQF in the construction of grid infrastructure.

Design/methodology/approach

The related factors of LFQF, including quality management (QM) practices, quality rectification, and individual learning, were identified by reviewing literature about organizational learning and extracting experience from previous failures. A questionnaire survey was distributed to the grid companies in North, Northeast, Northwest, East, Central, and Southwest China. 381 valid responses collected and analyzed using structural equation modeling (SEM) to test the influence of these factors on LFQF.

Findings

The SEM results support that QM practices positively affect individual learning and LFQF. Quality rectification indirectly impacts LFQF via individual learning, while the results did not support the direct link between quality rectification and LFQF.

Practical implications

The findings strengthen practical insights into extracting experience from poor-quality issues and continuous improvement. The contributory factors of LFQF found in this study benefit the practitioners by taking effective measures to enhance organizational learning capability and improve the long-term construction quality performance in the grid infrastructure industry.

Originality/value

Existing research about the application of LFQF still stays at the explorative and conceptual stage. This study investigates the related factors of LFQF, including QM practices, quality rectification, and individual learning, extending the model development of learning from failures (LFF) in construction QM.

Details

Engineering, Construction and Architectural Management, vol. 31 no. 4
Type: Research Article
ISSN: 0969-9988

Keywords

Article
Publication date: 27 September 2013

Martin Dixon

The purpose of this paper is to analyse whether title to land is secure in England and Wales when registered under the Land Registration Act 2002, in particular when a title is…

651

Abstract

Purpose

The purpose of this paper is to analyse whether title to land is secure in England and Wales when registered under the Land Registration Act 2002, in particular when a title is registered without the proprietor being able to establish good title under pre‐registration rules of property law.

Design/methodology/approach

This paper analyses reported judgments, with particular emphasis on the decision in Walker v. Burton [2012].

Findings

The paper identifies an uncertainty at the heart of the registration system: the uncertainty as to the extent to which a registered title may be rectified to remove the proprietor. This is acute when it appears that the registered proprietor has no claim to the land other than by reason of his registration. There may be a difference in this regard between intangible property titles and tangible titles.

Originality/value

The Land Registration Act 2002 is meant to replace registration of title with title by registration. The real force of this is only now being realised and there are few reported judgements, and less consistency, working out what this means in practice.

Details

International Journal of Law in the Built Environment, vol. 5 no. 3
Type: Research Article
ISSN: 1756-1450

Keywords

Article
Publication date: 16 October 2017

Chengtao Cai, Bing Fan, Xiangyu Weng, Qidan Zhu and Li Su

Because of their large field of view, omnistereo vision systems have been widely used as primary vision sensors in autonomous mobile robot tasks. The purpose of this article is to…

201

Abstract

Purpose

Because of their large field of view, omnistereo vision systems have been widely used as primary vision sensors in autonomous mobile robot tasks. The purpose of this article is to achieve real-time and accurate tracking by the omnidirectional vision robot system.

Design/methodology/approach

The authors provide in this study the key techniques required to obtain an accurate omnistereo target tracking and location robot system, including stereo rectification and target tracking in complex environment. A simple rectification model is proposed, and a local image processing method is used to reduce the computation time in the localization process. A target tracking method is improved to make it suitable for omnidirectional vision system. Using the proposed methods and some existing methods, an omnistereo target tracking and location system is established.

Findings

The experiments are conducted with all the necessary stages involved in obtaining a high-performance omnistereo vision system. The proposed correction algorithm can process the image in real time. The experimental results of the improved tracking algorithm are better than the original algorithm. The statistical analysis of the experimental results demonstrates the effectiveness of the system.

Originality/value

A simple rectification model is proposed, and a local image processing method is used to reduce the computation time in the localization process. A target tracking method is improved to make it suitable for omnidirectional vision system. Using the proposed methods and some existing methods, an omnistereo target tracking and location system is established.

Details

Industrial Robot: An International Journal, vol. 44 no. 6
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 23 October 2007

Jie Zhao, Shuchun Yu and Hegao Cai

The paper seeks to develop a stereo vision system based on a new binocular device. It aims to present an explicit‐implicit correction method to correct radial and tangential…

Abstract

Purpose

The paper seeks to develop a stereo vision system based on a new binocular device. It aims to present an explicit‐implicit correction method to correct radial and tangential distortion of image synchronously. It also aims to propose a step‐rotation rectification method to rectify epipolar error between stereo pairs.

Design/methodology/approach

Least squares technique was used in solving the explicit‐implicit correction model. When the step‐rotation rectification method was implemented, the technology of rotating image space was used.

Findings

The paper finds that the stereo vision system based on a new binocular device can be used in different circumstances, and it can obtain more eyeshot of cameras. The explicit‐implicit correction method can eliminate radial and tangential distortion of images, and the solution to this method is so easy that it can be solved by least squares technique. The theory of step‐rotation rectification is simple, and it is effective for rectifying epipolar error.

Practical implications

The explicit‐implicit correction method and step‐rotation rectification method can be used in correcting image distortion and epipolar error in stereo pairs collected by a stereo vision system. The new binocular device can be used in building a stereo vision system.

Originality/value

A new binocular device is developed in the paper. Explicit distortion method and implicit distortion method are united to correct image distortion. A step‐rotation rectification method is proposed to rectify epipolar error.

Details

Industrial Robot: An International Journal, vol. 34 no. 6
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 17 May 2021

Yuki Hidaka

The purpose of this paper is to develop a novel coupled analysis method for synchronous rectification alternators.

Abstract

Purpose

The purpose of this paper is to develop a novel coupled analysis method for synchronous rectification alternators.

Design/methodology/approach

An ideal diode module is embedded in a rectification circuit. The resistance of the diode module is set such that it is equal to the on-resistance of the MOS-FET modules in the generation mode. In a mode without power generation, the motor voltage is less than the bus voltage; a sufficiently large value is defined for simulating the infinite resistance.

Findings

Because there is no need to decide the switch timing in advance, only one round of coupled analysis is needed to evaluate the synchronous rectification alternators.

Research limitations/implications

As limited case study is denoted in this paper, much more case studies are needed to be discussed.

Practical implications

By using the proposed method, it can be fulfilled that generation characteristic of automotive alternators can be evaluated without using the control simulation or pre-conducted analysis to decide the switch timing.

Social implications

By using the proposed method, it can be fulfilled that generation characteristic of automotive alternators can be evaluated without using the control simulation or pre-conducted analysis to decide the switch timing.

Originality/value

In the proposed methods, the definition of diode module differs from that of a conventional coupled analysis.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 40 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 3 August 2020

Swapnali Makdey, Rajendra Patrikar and Mohammad Farukh Hashmi

A “spin-diode” is the spintronics equivalent of an electrical diode: applying an external magnetic field greater than the limit of spin-diode BT flips the spin-diode between an…

Abstract

Purpose

A “spin-diode” is the spintronics equivalent of an electrical diode: applying an external magnetic field greater than the limit of spin-diode BT flips the spin-diode between an isolating state and a conducting state [1]. While conventional electrical diodes are two-terminal devices with electrical current between the two terminals modulated by an electrical field, these two-terminal magneto resistive devices can generally be referred to as “spin-diodes” in which a magnetic field modulates the electrical current between the two terminals.

Design/methodology/approach

Current modulation and rectification are an important subject of electronics as well as spintronics spin diode is two-terminal magnetoresistive devices in which change in resistance in response to an applied magnetic field; this magnetoresistance occurs due to a variety of phenomena and with varying magnitudes and directions.

Findings

In this paper, an efficient rectifying spin diode is introduced. The resulting spin diode is formed from graphene gallium and indium quantum dots and antimony-doped molybdenum disulfide. Converting an alternating bias voltage to direct current is the main achievement of this model device with an additional profit of rectified spin-current. The non-equilibrium density functional theory with a Monte Carlo sampling method is used to evaluate the flow of electrons and rectification ratio of the system.

Originality/value

The results indicate that spin diode displaying both spin-current and charge-current rectification should be possible and may find practical application in nanoscale devices that combine logic and memory functions.

Details

Circuit World, vol. 47 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 26 June 2023

Argaw Gurmu, M. Reza Hosseini, Mehrdad Arashpour and Wellia Lioeng

Building defects are becoming recurrent phenomena in most high-rise buildings. However, little research exists on the analysis of defects in high-rise buildings based on data from…

Abstract

Purpose

Building defects are becoming recurrent phenomena in most high-rise buildings. However, little research exists on the analysis of defects in high-rise buildings based on data from real-life projects. This study aims to develop dashboards and models for revealing the most common locations of defects, understanding associations among defects and predicting the rectification periods.

Design/methodology/approach

In total, 15,484 defect reports comprising qualitative and quantitative data were obtained from a company that provides consulting services for the construction industry in Victoria, Australia. Data mining methods were applied using a wide range of Python libraries including NumPy, Pandas, Natural Language Toolkit, SpaCy and Regular Expression, alongside association rule mining (ARM) and simulations.

Findings

Findings reveal that defects in multi-storey buildings often occur on lower levels, rather than on higher levels. Joinery defects were found to be the most recurrent problem on ground floors. The ARM outcomes show that the occurrence of one type of defect can be taken as an indication for the existence of other types of defects. For instance, in laundry, the chance of occurrence of plumbing and joinery defects, where paint defects are observed, is 88%. The stochastic model built for door defects showed that there is a 60% chance that defects on doors can be rectified within 60 days.

Originality/value

The dashboards provide original insight and novel ideas regarding the frequency of defects in various positions in multi-storey buildings. The stochastic models can provide a reliable point of reference for property managers, occupants and sub-contractors for taking measures to avoid reoccurring defects; so too, findings provide estimations of possible rectification periods for various types of defects.

Details

Construction Innovation , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1471-4175

Keywords

Article
Publication date: 8 April 2016

Xiaonan Zhang, Sanyuan Shi, Hongyu Zhao, Man Lu and Xuguang Li

This paper aims to first analyze the reasons of a brick-wooden building tilts in Yunnan province in China. Then, a jacking method which combines the stress release methods and the…

Abstract

Purpose

This paper aims to first analyze the reasons of a brick-wooden building tilts in Yunnan province in China. Then, a jacking method which combines the stress release methods and the excavation of stress release trench were put forward.

Design/methodology/approach

This method uses the anchor static pile to guarantee the safety of the building in the process of rectifying.

Findings

The practice showed that the inclination rate of the building was stable in the process of jacking, which proved the efficiency of the proposed method.

Originality/value

It has a great value for similar rectification projects, and for the protection of cultural heritage and ancient buildings have a positive effect.

Details

World Journal of Engineering, vol. 13 no. 2
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 1 February 1995

Hana Kasalová

Examines an attempt at implementation of a total quality managementprogramme in a university hospital in the Czech Republic where patientsatisfaction was found to be very high…

1309

Abstract

Examines an attempt at implementation of a total quality management programme in a university hospital in the Czech Republic where patient satisfaction was found to be very high. Tentatively ascribes the “generosity error” to the historic experience of the population. Demonstrates that this factor may be compensated for by a mathematical process (“rectification”), which is derived from the assessment of every respondent’s general scale.

Details

International Journal of Health Care Quality Assurance, vol. 8 no. 1
Type: Research Article
ISSN: 0952-6862

Keywords

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