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| 2. |
- Zhao, Ming, et al.
(författare)
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Masked data analysis for storage reliability model with initial failures
- 2018
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Ingår i: Safety and Reliability - Safe Societies in a Changing World - Proceedings of the 28th International European Safety and Reliability Conference, ESREL 2018. - : CRC Press/Balkema. - 9780815386827 ; , s. 2565-2572
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Konferensbidrag (refereegranskat)abstract
- Storage reliability is of importance for the products that largely stay in storage in their total life-cycle such as warning systems for harmful radiation detection, rescue systems, many kinds of defense systems, etc. The storage reliability of a product is commonly defined as the probability that the product can perform its specific function for a period of specific storage time under specific storage environment. Logically, the failures of the product in storage should be identified with the same criteria as in its operation process. However, the failure data in storage may be observed indirectly through the maintenance or inspection activities. Nevertheless, when the storage reliability is concerned in general, the reliability model should take into consideration the possibility that the operational reliability does not start at 100%, for example, the one-shot product may have only 96% operational reliability when they are newly produced. In this paper, the storage reliability model with possibly initial failures, which are usually neglected at the beginning of storage in most of storage models, is studied on the statistical analysis method when the masked data are observed. The parametric estimation procedure, based on the Least Squares method, is developed generally by applying an EM-like (Expectation and Maximization) algorithm for the storage data in which some information about which components have caused the system failures is not known, namely the failure data are masked. The estimates of the model parameters including the initial reliability are formalized. In the case of exponentially distributed storage lifetime and series system, a numerical example is provided to illustrate the method and procedure though the method is not limited to such case. The results should be useful for planning a storage environment, decision-making concerning the maximum length of storage, maintenance strategy optimization and identifying the production quality.
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| 3. |
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| 4. |
- Hu, W, et al.
(författare)
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Iterative Strategy Analyze During Agile Development
- 2012
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Ingår i: Weidianzixue yu jisuanji [Microelectronics & Computer]. - 1000-7180. ; 29:5, s. 165-169
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, We used characteristic of the Unified Modeling Language （UML） use case model in describing the function of the system＇ s and the iteration sequence of agile development process to obtain a new iteration sequence based on the risk an value of the various use cases in UML use case diagrams. An obvious advantage of doing so is to ensure high-risk and high-value use cases will be first developed, so that the use cases will be repeatedly tested in the next iteration, thereby increasing overall system reliability.
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| 5. |
- Hu, W., et al.
(författare)
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Requires analysis based on software maintainability
- 2014
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Ingår i: ICRMS 2014 - Proceedings of 2014 10th International Conference on Reliability, Maintainability and Safety. - 9781479919925 ; , s. 354-357
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Konferensbidrag (refereegranskat)abstract
- Requirements analysis is the most important phase of the software life cycle process. Some studies have shown the most faults of software are from the requirements phase. Therefore, the quality of Software Requirements Specification has become the key to project success, which correctness, consistency, no ambiguity of software requirements specification is more important. This paper presents a classification method based on natural language processing techniques and grey similar correlation. The first step of this method is that keywords refined from various functional requirements through segmentation of natural language processing, thus made up of heavy weight vector based on the weight of functional requirements, such a functional requirement corresponds to a weight vector. The second step is that the related technology of grey system is used to compute grey correlation coefficient between two weight vectors, in order to construct a correlation matrix. Finally, the appropriate statistical tools are used to classify functional requirements statements. The clustering results based on this method can provide work guidance for requirement analysts, software developers, software testers, software maintenance.
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| 6. |
- Hu, W, et al.
(författare)
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VDM++ Formalization of UML Class Diagram
- 2012
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Ingår i: Weidianzixue yu jisuanji [Microelectronics & Computer]. - 1000-7180. ; 29:6, s. 104-107
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this paper is to use the most widely used formal language-VDM ＋ ＋ that has characteristics of accuracy and consistent in describing syntax and semantic of the system model, combined with VDMTOOLS and Rational Rose tool to transform the various elements of the UML class model into representation of VI）M＋ ＋. This method achieves the various elements contained UML class model about the syntax and semantics checking, and further improves the quality of UML modeling.
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| 7. |
- Jandrić, Petar, et al.
(författare)
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Teaching in the Age of Covid-19
- 2020
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Ingår i: Postdigital Science and Education. - : Springer Science and Business Media LLC. - 2524-4868 .- 2524-485X. ; 2:3, s. 1069-1230
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A collection of 84 author's testimonies and workspace photographs between 18 March and 5 May 2020.
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| 8. |
- Wang, X., et al.
(författare)
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Reliability analysis and evaluation of gas supply system
- 2009
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Ingår i: ICMET'09 - Proceedings of the 2009 International Conference on Mechanical and Electrical Technology. - Beijing. - 9780791802946 ; , s. 245-249
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, the reliability model and the evaluation methods were neatly used with combining the engineering practice of the noise laboratory supply system, and this study give a quantitative evaluation result of the reliability system. It provides the scientific basis for improving the engineering design and increasing the reliability. This research results can be extended to similar projects, such as fuel supply system. From an engineering point of view, it is an innovation that the filter in the system is identified to be a "series - parallel mixed" structure by considering its physical structure and performance requirement.
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| 9. |
- Yang, Bin, et al.
(författare)
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A review of advanced air distribution methods - theory, practice, limitations and solutions
- 2019
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Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788 .- 1872-6178. ; 202
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Tidskriftsartikel (refereegranskat)abstract
- Ventilation and air distribution methods are important for indoor thermal environments and air quality. Effective distribution of airflow for indoor built environments with the aim of simultaneously offsetting thermal and ventilation loads in an energy efficient manner has been the research focus in the past several decades. Based on airflow characteristics, ventilation methods can be categorized as fully mixed or non-uniform. Non-uniform methods can be further divided into piston, stratified and task zone ventilation. In this paper, the theory, performance, practical applications, limitations and solutions pertaining to ventilation and air distribution methods are critically reviewed. Since many ventilation methods are buoyancy driving that confines their use for heating mode, some methods suitable for heating are discussed. Furthermore, measuring and evaluating methods for ventilation and air distribution are also discussed to give a comprehensive framework of the review.
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| 10. |
- Yang, H., et al.
(författare)
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Numerical investigations of Re-independence and influence of wall heating on flow characteristics and ventilation in full-scale 2D street canyons
- 2021
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Ingår i: Building and Environment. - : IEEE. - 0360-1323 .- 1873-684X. ; 189
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Tidskriftsartikel (refereegranskat)abstract
- Validated by wind tunnel data, this study numerically investigates the integrated impacts of wind and thermal buoyancy on urban turbulence, ventilation and pollutant dispersion in full-scale 2D deep street canyons (aspect ratio AR = H/W = 3 and 5, W = 24 m). Isothermal urban airflows for such deep street canyons can be Reynolds-number-independent when reference Reynolds number (Re) exceeds the critical Re (Rec~106,107 when AR = 3, 5), i.e. AR = 5 experiences two main vortices and one-order smaller NEV* (~10−3, the normalized net escape velocity) than AR = 3 with a single main vortex (NEV*~10−2). With sufficiently large Re (Re > Rec) and the same air-wall temperature difference (Ri = 2.62, 4.36 when AR = 3, 5), four uniform wall heating patterns were considered, including leeward-wall heating (L-H), windward-wall heating (W–H), ground heating (G-H), and all-wall heating (A-H). Various indicators were adopted to evaluate street ventilation and pollutant dilution capacity (e.g. age of air (τ,s), NEV*, pollutant transport rates (PTR)). Full-scale wall heating produces a strong upward near-wall buoyancy force, which significantly influences flow patterns and improves street ventilation for most cases. When AR = 3, L-H strengthens the single-vortex airflow. When AR = 5, L-H converts the isothermal double vortices into a single-clockwise vortex. For both ARs, W–H reverses the main clockwise vortex to an enhanced counterclockwise one, moreover G-H and A-H cause a more complicated multi-vortex pattern than isothermal cases. Overall, when AR = 3, L-H and W–H increase NEV* by 68% and 40% than the isothermal case. When AR = 5, four wall heating patterns all raise NEV* considerably (by 150%–556%). For both ARs, the L-H, W–H and A-H amplify the contribution of mean flows on removing pollutants but reduce that by turbulent diffusion compared with isothermal cases.
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