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A method for automatic detection of burning through of short circuit CO_2 arc welding is presented. It is based on the extraction of arc signal features as well as classification of the obtained features using self-organize featur...
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A method for automatic detection of burning through of short circuit CO_2 arc welding is presented. It is based on the extraction of arc signal features as well as classification of the obtained features using self-organize feature map (SOM) neural networks in order to get the weld quality information, for example, to determine if there is defect in the product. This is important for the on-line monitoring of weld quality especially in robotic welding and lay the foundation for the further real-time control of weld quality.
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The purpose of this study is to extract defect-forecasting method by influencing factors of the apartment construction with become the nationwide concern due to recent tremendous casualties on Korean apartment housing For this, th...
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The purpose of this study is to extract defect-forecasting method by influencing factors of the apartment construction with become the nationwide concern due to recent tremendous casualties on Korean apartment housing For this, the study tried to forecast defect occurrence by presenting a regression formula when the defect factors Analysed to have affected the defect occurrence were interwoven with each other; the construction company, the construction method and contract method.
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The burn-in test time is an important parameter of the complex batch processing machine scheduling problem. The omission of the loss of quality deviations in manufacturing generates a non-comprehensive and imperfect result in the ...
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The burn-in test time is an important parameter of the complex batch processing machine scheduling problem. The omission of the loss of quality deviations in manufacturing generates a non-comprehensive and imperfect result in the optimisation of burn-in time, which hinders the identification of proactive and economical optimisation strategies to prevent infant failure in manufacturing. To solve this problem, this study visualises and quantifies for the first time the hidden loss caused by quality deviations in manufacturing and uses it as a newly added constraint to optimise the burn-in time. Firstly, a quality loss model composed of visible yield loss and warranty costs related to measurable but undetectable reliability vulnerabilities is defined. Secondly, the loss effects of growing defects are measured during the burn-in test, and the optimal burn-in time expressed by the proposed quality loss model is traded off between the additional burn-in cost and the decreased quality loss for an acceptable low infant failure rate. Finally, the effectiveness of the proposed optimisation approach is demonstrated using actual data from a control board with a high infant failure rate. Results show that the proposed method can systematically combine the fundamental loss of quality deviations in the optimisation of burn-in time, which supplements the commonly used optimality criteria, with the upstream loss of quality deviations in the form of manufacturing defects.
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Before any investigation takes place, I think it is necessary to define exactly the families of the components form mg the release agent: Lubricants and release agents arc O/W (oil in water) emulsions. The anhydrous fraction (on a...
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Before any investigation takes place, I think it is necessary to define exactly the families of the components form mg the release agent: Lubricants and release agents arc O/W (oil in water) emulsions. The anhydrous fraction (on average from 20 to 30 percent) supplies the intrinsic properties to the film which forms on the die after water evaporation (both the one contained in the concentrate and, especially, the one used for the dilution, which normally corresponds to 99-98 percent of the whole diluted product applied on the die). Beside this ensemble of active principles a Package of Surfactants has the double function to realize the concentrated emulsion and to increase the filming power of the diluted product applied on the die at each cycle. At present, completely anhydrous products are being developed, but they arc not the object of the present study, as they represent an operating solution which, on my opinion, is not practicable in most cases, if applied at each cycle. In fact, most operators agree by now, that the functions of the release agent are principally two []: 1. to build a film able to lubricate and release the alloy injected into the cavity of the die; 2. to take off heat at each cycle be means of the evaporation of the dilution water. It is evident that the anhydrous products don't perform the second function which, as we will see, is very important, particularly in production conditions where cycle times are constantly being reduced (automation of production phases, increase of productivity, etc.). Independently of the physical form in which the product is supplied to the final user, the main property of the film that forms on the die is the composition of the anhydrous fraction, that will have a certain effect on some of the main process variables. In the following paragraph, the most important intrinsic properties and the relevant effects on the production out-put, will be described.
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The construction sector accounts for a significant portion of the total final energy use and carbon emissions worldwide. Despite efforts to reduce energy consumption through energy efficiency improvements in buildings, the measure...
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The construction sector accounts for a significant portion of the total final energy use and carbon emissions worldwide. Despite efforts to reduce energy consumption through energy efficiency improvements in buildings, the measures proposed by the construction sector are falling short. Among several causes which lead buildings to perform differently to what was defined in the design stage, commonly referred to as the 'energy performance gap', the occurrence of quality defects has been acknowledged. This paper aims to identify through an in-depth literature review, quality defects which undermine the thermal performance of buildings by comparing the studies' findings with regard to defect characteristics and attributes; major causes and influencing factors; and their impact on the energy performance of construction projects. This review also aims to highlight areas where more research is needed if the expected thermal performance of buildings is to be achieved. Understanding the generation process and effects of defects on the energy efficiency of buildings can support the implementation of appropriate quality management systems in construction projects and thus contribute to the achievement of the intended energy performance targets.
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The building industry is noted for its repeated building defects causing cost increases and time delays during construction. In Spain, despite the Ley de Ordenacion de la Edification (Building Regulation Act), which establishes a ...
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The building industry is noted for its repeated building defects causing cost increases and time delays during construction. In Spain, despite the Ley de Ordenacion de la Edification (Building Regulation Act), which establishes a general framework to promote overall building quality, construction defects in residential buildings remain a pervasive problem. An analysis of 3647 construction defects is presented which identified the location within the building, subcontractors and building element in 68 residential building developments undertaken by two large Spanish contractors. The research reveals that the most common defects that arise during construction are related to the stability of the structure and inappropriate installation of roofs and facades. These technical faults are caused by poor workmanship rather than by the quality of the materials or products used. By comparing these results with a previous study on defects after handover, it can be concluded that while the nature of defects during construction is basically technical, at handover it is aesthetic or technical.
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Software quality is an important topic of software development and it is always challenging to deliver high-quality software. The major challenges, to complete the software, are time and cost without losing the software quality. S...
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Software quality is an important topic of software development and it is always challenging to deliver high-quality software. The major challenges, to complete the software, are time and cost without losing the software quality. Software quality has a significant impact on software performance. The acceptability, success, and failure of software are depending on its level of quality and number of defects. Software defects are one of the fundamental factors that can determine the time of software delivery. In addition, defects or errors need to be eliminated before software delivery. Software companies spend a lot to reduce code defects. The aim is to detect defects early with cheaper methods. This paper proposes a code quality scanner to decrease the code defects. The proposed solution is a combination of code scanner and code review. Moreover, the paper presents results using quantitative analysis to show the effectiveness of the proposed solution. The results are found encouraging.
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One of the key aspects of project management is to deliver a high-quality product and at the same time balance the cost and lead-time constraints. Hence, care should be taken to ensure that neither too much nor too little effort i...
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One of the key aspects of project management is to deliver a high-quality product and at the same time balance the cost and lead-time constraints. Hence, care should be taken to ensure that neither too much nor too little effort is spent to build quality into the product. In product development scenarios in particular, it is very important to use the right project management practices to achieve the needed quality level and simultaneously respect the project lead-time and cost factors. This article provides insight into a simple, pragmatic, proactive project management method that can be used to measure product reliability (as early as code reading). The highlight of this reliability model is that it can be used in projects or organizations without adding any burden to the project management team, thus leading to a more global acceptance of this model.
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This article is a case study of how an automobile door manufacturer developed and uses a Quality Improvement Data Management System based on existing in-process inspection records, specifically those for metal surface defects on t...
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This article is a case study of how an automobile door manufacturer developed and uses a Quality Improvement Data Management System based on existing in-process inspection records, specifically those for metal surface defects on the outer door. The authors explain their belief that automotive suppliers who do not capitalise on the potential value of their quality records to steer quality improvement are missing out on a ready source of competitive advantage. The main features of the system are its ability to stratify the inspection data into numerous dimensions, focus on visual presentation of the information, integration of simple statistical tools, such as defect concentration diagrams, and ease of use. These features were desired by potential users including the quality manager, quality engineers, and quality improvement teams, and guided the system design. The system design and software implementation are described, and example applications to real production records are provided.
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We present a study of 600 Java software networks with the aim of characterizing the relationship among their defectiveness and community metrics. We analyze the community structure of such networks, defined as their topological di...
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We present a study of 600 Java software networks with the aim of characterizing the relationship among their defectiveness and community metrics. We analyze the community structure of such networks, defined as their topological division into subnetworks of densely connected nodes. A high density of connections represents a higher level of cooperation between classes, so a well-defined division in communities could indicate that the software system has been designed in a modular fashion and all its functionalities are well separated. We show how the community structure can be an indicator of well-written, high quality code by retrieving the communities of the analyzed systems and by ranking their division in communities through the built-in metric called modularity. We found that the software systems with highest modularity possess the majority of bugs, and tested whether this result is related to some confounding effect. We found two power laws relating the maximum defect density with two different metrics: the number of detected communities inside a software network and the clustering coefficient. We finally found a linear correlation between clustering coefficient and number of communities. Our results can be used to make predictive hypotheses about software defectiveness of future releases of the analyzed systems.
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