期刊文献+
共找到1,727篇文章
< 1 2 87 >
每页显示 20 50 100
Model-Based Systems Engineering Approach to Design a Human Settlement to Better Serve Displaced People
1
作者 Anicet Adjahossou 《Open Journal of Applied Sciences》 2024年第4期865-880,共16页
The challenge of transitioning from temporary humanitarian settlements to more sustainable human settlements is due to a significant increase in the number of forcibly displaced people over recent decades, difficultie... The challenge of transitioning from temporary humanitarian settlements to more sustainable human settlements is due to a significant increase in the number of forcibly displaced people over recent decades, difficulties in providing social services that meet the required standards, and the prolongation of emergencies. Despite this challenging context, short-term considerations continue to guide their planning and management rather than more integrated, longer-term perspectives, thus preventing viable, sustainable development. Over the years, the design of humanitarian settlements has not been adapted to local contexts and perspectives, nor to the dynamics of urbanization and population growth and data. In addition, the current approach to temporary settlement harms the environment and can strain limited resources. Inefficient land use and ad hoc development models have compounded difficulties and generated new challenges. As a result, living conditions in settlements have deteriorated over the last few decades and continue to pose new challenges. The stakes are such that major shortcomings have emerged along the way, leading to disruption, budget overruns in a context marked by a steady decline in funding. However, some attempts have been made to shift towards more sustainable approaches, but these have mainly focused on vague, sector-oriented themes, failing to consider systematic and integration views. This study is a contribution in addressing these shortcomings by designing a model-driving solution, emphasizing an integrated system conceptualized as a system of systems. This paper proposes a new methodology for designing an integrated and sustainable human settlement model, based on Model-Based Systems Engineering and a Systems Modeling Language to provide valuable insights toward sustainable solutions for displaced populations aligning with the United Nations 2030 agenda for sustainable development. 展开更多
关键词 Humanitarian Settlement Human Settlement Sustainability systems Engineering model-based systems Engineering systems modeling Language
下载PDF
The Impact of Model Based Offset Scaling Technique on the Amplitude Variation with Offset Responses from 3D Seismic Data Acquired from the Tano Basin, Offshore Ghana
2
作者 Striggner Bedu-Addo Sylvester Kojo Danuor Aboagye Menyeh 《International Journal of Geosciences》 CAS 2024年第1期40-53,共14页
Amplitudes have been found to be a function of incident angle and offset. Hence data required to test for amplitude variation with angle or offset needs to have its amplitudes for all offsets preserved and not stacked... Amplitudes have been found to be a function of incident angle and offset. Hence data required to test for amplitude variation with angle or offset needs to have its amplitudes for all offsets preserved and not stacked. Amplitude Variation with Offset (AVO)/Amplitude Variation with Angle (AVA) is necessary to account for information in the offset/angle parameter (mode converted S-wave and P-wave velocities). Since amplitudes are a function of the converted S- and P-waves, it is important to investigate the dependence of amplitudes on the elastic (P- and S-waves) parameters from the seismic data. By modelling these effects for different reservoir fluids via fluid substitution, various AVO geobody classes present along the well and in the entire seismic cube can be observed. AVO analysis was performed on one test well (Well_1) and 3D pre-stack angle gathers from the Tano Basin. The analysis involves creating a synthetic model to infer the effect of offset scaling techniques on amplitude responses in the Tano basin as compared to the effect of unscaled seismic data. The spectral balance process was performed to match the amplitude spectra of all angle stacks to that of the mid (26°) stack on the test lines. The process had an effect primarily on the far (34° - 40°) stacks. The frequency content of these stacks slightly increased to match that of the near and mid stacks. In offset scaling process, the root mean square (RMS) amplitude comparison between the synthetic and seismic suggests that the amplitude of the far traces should be reduced relative to the nears by up to 16%. However, the exact scaler values depend on the time window considered. This suggests that the amplitude scaling with offset delivered from seismic processing is only approximately correct and needs to be checked with well synthetics and adjusted accordingly prior to use for AVO studies. The AVO attribute volumes generated were better at resolving anomalies on spectrally balanced and offset scaled data than data delivered from conventional processing. A typical class II AVO anomaly is seen along the test well from the cross-plot analysis and AVO attribute cube which indicates an oil filled reservoir. 展开更多
关键词 Amplitude Variation with Offset (AVO) model based Offset Scaling Technique Tano Basin
下载PDF
A Custom Manipulator for Dental Implantation Through Model-Based Design 被引量:1
3
作者 Anitha Govindhan Karnam Anantha Sunitha Sivanathan Kandhasamy 《Intelligent Automation & Soft Computing》 SCIE 2023年第1期351-365,共15页
This paper presents a Model-Based Design(MBD)approach for the design and control of a customized manipulator intended for drilling and position-ing of dental implants accurately with minimal human intervention.While p... This paper presents a Model-Based Design(MBD)approach for the design and control of a customized manipulator intended for drilling and position-ing of dental implants accurately with minimal human intervention.While performing an intra-oral surgery for a prolonged duration within a limited oral cavity,the tremor of dentist's hand is inevitable.As a result,wielding the drilling tool and inserting the dental implants safely in accurate position and orientation is highly challenging even for experienced dentists.Therefore,we introduce a customized manipulator that is designed ergonomically by taking in to account the dental chair specifications and anthropomorphic data such that it can be readily mounted onto the existing dental chair.The manipulator can be used to drill holes for dental inserts and position them with improved accuracy and safety.Further-more,a thorough multi-body motion analysis of the manipulator was carried out by creating a virtual prototype of the manipulator and simulating its controlled movements in various scenarios.The overall design was prepared and validated in simulation using Solid works,MATLAB and Simulink through Model Based Design(MBD)approach.The motion simulation results indicate that the manipulator could be built as a prototype readily. 展开更多
关键词 model based design multi-body motion simulation custom manipulator orthodontic implants mathematical approach
下载PDF
Feedback Scheduling of Model-based Networked Control Systems with Flexible Workload 被引量:4
4
作者 Xian-Ming Tang Jin-Shou Yu 《International Journal of Automation and computing》 EI 2008年第4期389-394,共6页
In this paper,a novel control structure called feedback scheduling of model-based networked control systems is proposed to cope with a flexible network load and resource constraints.The state update time is adjusted a... In this paper,a novel control structure called feedback scheduling of model-based networked control systems is proposed to cope with a flexible network load and resource constraints.The state update time is adjusted according to the real-time network congestion situation.State observer is used under the situation where the state of the controlled plant could not be acquired.The stability criterion of the proposed structure is proved with time-varying state update time.On the basis of the stability of the novel system structure,the compromise between the control performance and the network utilization is realized by using feedback scheduler. Examples are provided to show the advantage of the proposed control structure. 展开更多
关键词 model-based networked control system state update time stability criterion feedback scheduling.
下载PDF
Redesigning the Model of Book Evaluation in the Polish Performance-based Research Funding System 被引量:2
5
作者 Emanuel Kulczycki Przemyslaw Korytkowski 《Journal of Data and Information Science》 CSCD 2018年第4期61-73,共13页
Purpose: This study aims to present the key systemic changes in the Polish book evaluation model to focus on the publisher list, as inspired by the Norwegian Model. Design/methodology/approach: In this study we recons... Purpose: This study aims to present the key systemic changes in the Polish book evaluation model to focus on the publisher list, as inspired by the Norwegian Model. Design/methodology/approach: In this study we reconstruct the framework of the 2010 and 2018 models of book evaluation in Poland within the performance-based research funding system. Findings: For almost 20 years the book evaluation system in Poland has been based on the verification of various technical criteria(e.g. length of the book). The new 2018 model is based on the principle of prestige inheritance(a book is worth as much as its publisher is) and is inspired by the publisher list used in the Norwegian Model. In this paper, we argue that this solution may be a more balanced policy instrument than the previous 2010 model in which neither the quality of the publisher nor the quality of the book played any role in the evaluation.Research limitations: We work from the framework of the 2018 model of book evaluation specified in the law on higher education and science from 20 July 2018, as implementation acts are not available yet. Practical implications: This study may provide a valuable point of reference on how structural reforms in the research evaluation model were implemented on a country level. The results of this study may be interesting to policy makers, stakeholders and researchers focused on science policy. Originality/value: This is the very first study that presents the new framework of the Polish research evaluation model and policy instruments for scholarly book evaluation. We describe what motivated policy makers to change the book evaluation model, and what arguments were explicitly raised to argue for the new solution. 展开更多
关键词 Book evaluation Norwegian model Performance-based research funding system Poland Publisher list
下载PDF
On the model-based networked control for singularly perturbed systems 被引量:1
6
作者 Hongwang YU Zhiming WANG Yufan ZHENG 《控制理论与应用(英文版)》 EI 2008年第2期153-162,共10页
In this paper, the control of a two-time-scale plant, where the sensor is connected to a linear controller/ actuator via a network is addressed. The slow and fast systems of singularly perturbed systems are used to pr... In this paper, the control of a two-time-scale plant, where the sensor is connected to a linear controller/ actuator via a network is addressed. The slow and fast systems of singularly perturbed systems are used to produce an estimate of the plant state behavior between transmission times, by which one can reduce the usage of the network. The approximate solutions of the whole systems are derived and it is shown that the whole systems via the network control are generally asymptotically stable as long as their slow and fast systems are both stable. These results are also extended to the case of network delay. 展开更多
关键词 model-based networked control systems Singularly perturbed control systems Asymptotically stable Globally practical stability
下载PDF
Auxiliary Model Based Multi-innovation Stochastic Gradient Identification Methods for Hammerstein Output-Error System
7
作者 冯启亮 贾立 李峰 《Journal of Donghua University(English Edition)》 EI CAS 2017年第1期53-59,共7页
Special input signals identification method based on the auxiliary model based multi-innovation stochastic gradient algorithm for Hammerstein output-error system was proposed.The special input signals were used to rea... Special input signals identification method based on the auxiliary model based multi-innovation stochastic gradient algorithm for Hammerstein output-error system was proposed.The special input signals were used to realize the identification and separation of the Hammerstein model.As a result,the identification of the dynamic linear part can be separated from the static nonlinear elements without any redundant adjustable parameters.The auxiliary model based multi-innovation stochastic gradient algorithm was applied to identifying the serial link parameters of the Hammerstein model.The auxiliary model based multi-innovation stochastic gradient algorithm can avoid the influence of noise and improve the identification accuracy by changing the innovation length.The simulation results show the efficiency of the proposed method. 展开更多
关键词 Hammerstein output-error system special input signals auxiliary model based multi-innovation stochastic gradient algorithm innovation length
下载PDF
3DV quality model based depth maps for view synthesis in FTV system
8
作者 张秋闻 安平 +2 位作者 张艳 张兆杨 王元庆 《Journal of Shanghai University(English Edition)》 CAS 2011年第4期335-341,共7页
Depth maps are used for synthesis virtual view in free-viewpoint television (FTV) systems. When depth maps are derived using existing depth estimation methods, the depth distortions will cause undesirable artifacts ... Depth maps are used for synthesis virtual view in free-viewpoint television (FTV) systems. When depth maps are derived using existing depth estimation methods, the depth distortions will cause undesirable artifacts in the synthesized views. To solve this problem, a 3D video quality model base depth maps (D-3DV) for virtual view synthesis and depth map coding in the FTV applications is proposed. First, the relationships between distortions in coded depth map and rendered view are derived. Then, a precisely 3DV quality model based depth characteristics is develop for the synthesized virtual views. Finally, based on D-3DV model, a multilateral filtering is applied as a pre-processed filter to reduce rendering artifacts. The experimental results evaluated by objective and subjective methods indicate that the proposed D-3DV model can reduce bit-rate of depth coding and achieve better rendering quality. 展开更多
关键词 free-viewpoint television (FTV) 3D video quality model base depth maps (D-3DV) view synthesis
下载PDF
Knowledge-Based Multifaceted Modeling Methodology for Open Complex Giant Systems
9
作者 Qin, Shiyin 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1997年第3期34-42,共9页
In this paper, the structure characteristics of open complex giant systems are concretely analysed in depth, thus the view and its significance to support the meta synthesis engineering with manifold knowledge models... In this paper, the structure characteristics of open complex giant systems are concretely analysed in depth, thus the view and its significance to support the meta synthesis engineering with manifold knowledge models are clarified. Furthermore, the knowledge based multifaceted modeling methodology for open complex giant systems is emphatically studied. The major points are as follows: (1) nonlinear mechanism and general information partition law; (2) from the symmetry and similarity to the acquisition of construction knowledge; (3) structures for hierarchical and nonhierarchical organizations; (4) the integration of manifold knowledge models; (5) the methodology of knowledge based multifaceted modeling. 展开更多
关键词 Knowledge based multifaceted modeling Open complex giant systems Metasynthesis engineering Interpretive structural modeling.
下载PDF
Model-Based Degree Estimation of Unbalance and Misalignment in Flexible Coupling-rotor System 被引量:5
10
作者 LI Changyou XU Minqiang +2 位作者 GUO Song WANG Yuewu WANG Rixin 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2009年第4期550-556,共7页
The condition of rotor system must be assessed in order to develop condition-based maintenance for rotating machinery. It is determined by multiple variables such as unbalance degree, misalignment degree, the amount o... The condition of rotor system must be assessed in order to develop condition-based maintenance for rotating machinery. It is determined by multiple variables such as unbalance degree, misalignment degree, the amount of bending deformation of the shaft, occurrence of shaft crack of rotor system and so on. The estimation of the degrees of unbalance and misalignment in flexible coupling-rotor system is discussed. The model-based approach is employed to solve this problem. The models of the equivalent external loads for unbalance and misalignment are derived and analyzed. Then, the degrees of unbalance and misalignment are estimated by analyzing the components of the equivalent external loads of which the frequencies are equal to the 1 and 2 times running frequency respectively. The equivalent external loads are calculated according to the dynamic equation of the original rotor system and the differences between the dynamical responses in normal case and the vibrations when the degree of unbalance or misalignment or both changes. The denoise method based on bandpass filter is used to decrease the effect of noise on the estimation accuracy. The numerical examples are given to show that the proposed approach can estimate the degrees of unbalance and misalignment of the flexible coupling-rotor system accurately. 展开更多
关键词 model-based approach degree estimation MISALIGNMENT UNBALANCE rotor system flexible coupling
下载PDF
A Systems Approach to Assessing Sustainability Capacity in Kalobeyei Refugee Settlement in Turkana County, Kenya
11
作者 Anicet Adjahossou 《Open Journal of Applied Sciences》 2024年第4期833-848,共16页
Refugee settlements face several challenges in transitioning from a temporary planning approach to more sustainable settlements. This is mainly due to an increase in the number of forcibly displaced people over the la... Refugee settlements face several challenges in transitioning from a temporary planning approach to more sustainable settlements. This is mainly due to an increase in the number of forcibly displaced people over the last few decades, and the difficulties of sustainably providing social services that meet the required standards. The development of refugee settlements assumed that forcibly displaced people would return to their places or countries of origin. Unfortunately, displacement situations are prolonged indefinitely, forcing these people to spend most of their lives in conditions that are often deplorable and substandard, and therefore unsustainable. In most cases, the establishment of refugee settlements is triggered by an emergency caused by an influx of forcibly displaced people, who need to be accommodated urgently and provided with some form of international assistance and protection. This leaves little or no time for proper planning for long-term development as required. In addition, the current approach to temporary settlement harms the environment and can strain limited resources with ad hoc development models that have exacerbated difficulties. As a result, living conditions in refugee settlements have deteriorated over the last few decades and continue to pose challenges as to how best to design, plan, and sustain settlements over time. To contribute to addressing these challenges, this study proposes a new methodology supported by Model-Based Systems Engineering (MBSE) and a Systems Modeling Language (SysML) to develop a typical sustainable human settlement system model, which has functionally and operationally executed using a Systems Engineering (SE) approach. To assess the sustainability capacity of the proposed system, this work applies a matrix of crossed impact multiplication through a case study by conducting a system capacity interdependence analysis (SCIA) using the MICMAC methodology (Cross-impact matrix multiplication applied to classification) to assess the interdependency that exist between the sub-systems categories to deliver services at the system level. The sustainability analysis results based on capacity variables influence and dependency models shows that development activities in the settlement are unstable and, therefore, unsustainable since there is no apparent difference between the influential and dependent data used for the assessment. These results illustrate that an integrated system could improve human settlements’ sustainability and that capacity building in service delivery is beneficial and necessary. 展开更多
关键词 Humanitarian Settlement systems Engineering (SE) SUSTAINABILITY Capacity Assessment model-based systems Engineering (MBSE) systems modeling Language (SysML)
下载PDF
A Triple Nexus Water-Energy-Housing (WEH) Framework Modelling towards Improved Decision-Making in Humanitarian Operations
12
作者 Anicet Adjahossou 《Open Journal of Applied Sciences》 2024年第4期927-949,共23页
Given the challenges facing most humanitarian operations worldwide, a change of approach is needed to ensure greater sustainability of humanitarian settlements right from the planning stage. Some studies attribute uns... Given the challenges facing most humanitarian operations worldwide, a change of approach is needed to ensure greater sustainability of humanitarian settlements right from the planning stage. Some studies attribute unsustainability to inadequate provision of basic resources and highlight the apparent bottlenecks that prevent access to the meaningful data needed to plan and remedy problems. Most operations have relied on an “ad hoc ism” approach, employing parallel and disconnected data processing methods, resulting in a wide range of data being collected without subsequent prioritization to optimize interconnections that could enhance performance. There have been little efforts to study the trade-offs potentially at stake. This work proposes a new framework enabling all subsystems to operate in a single system and focusing on data processing perspective. To achieve this, this paper proposes a Triple Nexus Framework as an attempt to integrate water, energy, and housing sector data derived from a specific sub-system within the overall system in the application of Model-Based Systems Engineering. Understanding the synergies between water, energy, and housing, Systems Engineering characterizes the triple nexus framework and identifies opportunities for improved decision-making in processing operational data from these sectors. Two scenarios illustrate how an integrated platform could be a gateway to access meaningful operational data in the system and a starting point for modeling integrated human settlement systems. Upon execution, the model is tested for nexus megadata processing, and the optimization simulation yielded 67% satisfactory results, demonstrating that an integrated system could improve sustainability, and that capacity building in service delivery is more than beneficial. 展开更多
关键词 Humanitarian Settlement Nexus Framework WATER ENERGY HOUSING Sustainability systems Engineering (SE) model-based systems Engineering (MBSE) systems modeling Language (SysML)
下载PDF
Integrating Knowledge-Based Simulation with Aspiration-Directed Model-based Decision Support System
13
作者 Feng Shan & Li D. Xu(Department of Automatic Control Engineering,Huazhong University of Science and Technology Wuhan, Hubei 430074, China)(Department of Management Science and Information systems Wright State University, Dayton, OH 45435, USA) 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1996年第2期25-33,共9页
This paper reports an aspiration-directed, model-based decision support system (AMDSS) integrated with a knowledge-based simulation system. The system is designed to study China's mid-range economic development st... This paper reports an aspiration-directed, model-based decision support system (AMDSS) integrated with a knowledge-based simulation system. The system is designed to study China's mid-range economic development strategy. The capacity of the system is enhanced by the knowledge-based component which provides a knowledge-based simulation environment for model management. Currently the system has passed the stage of prototype and achieves its implementation capacity. The paper first presents the mathematical aspects of decision making including aspiration-directed decision making, then discusses the architecture of the system. The purpose of the paper is to provide insights into how such an integrated system could provide decision support for complex decision analysis. 展开更多
关键词 Knowledge-based simulation model-based reasoning Decision support system
下载PDF
Nonlinear Systems Identification via an Input-Output Model Based on a Feedforward Neural Network
14
作者 O. L. Shuai South China University of Technology, Gungzhou, 510641, P.R. China S. C. Zhou S. K. Tso T. T. Wong T.P. Leung The Hong Kong Polytechnic University, HungHom, Kowloon, HK 《International Journal of Plant Engineering and Management》 1997年第4期45-50,共6页
This paper develops a feedforward neural network based input output model for a general unknown nonlinear dynamic system identification when only the inputs and outputs are accessible observations. In the developed m... This paper develops a feedforward neural network based input output model for a general unknown nonlinear dynamic system identification when only the inputs and outputs are accessible observations. In the developed model, the size of the input space is directly related to the system order. By monitoring the identification error characteristic curve, we are able to determine the system order and subsequently an appropriate network structure for systems identification. Simulation results are promising and show that generic nonlinear systems can be identified, different cases of the same system can also be discriminated by our model. 展开更多
关键词 nonlinear dynamic systems identification neural networks based Input Output model identification error characteristic curve
下载PDF
The Flemish Performance-based Research Funding System: A Unique Variant of the Norwegian Model 被引量:5
15
作者 Tim C.E.Engels Raf Guns 《Journal of Data and Information Science》 CSCD 2018年第4期45-60,共16页
The BOF-key is the performance-based research funding system that is used in Flanders, Belgium. In this paper we describe the historical background of the system, its current design and organization, as well as its ef... The BOF-key is the performance-based research funding system that is used in Flanders, Belgium. In this paper we describe the historical background of the system, its current design and organization, as well as its effects on the Flemish higher education landscape. The BOFkey in its current form relies on three bibliometric parameters: publications in Web of Science, citations in Web of Science, and publications in a comprehensive regional database for SSH publications. Taken together, the BOF-key forms a unique variant of the Norwegian model: while the system to a large extent relies on a commercial database, it avoids the problem of inadequate coverage of the SSH. Because the bibliometric parameters of the BOF-key are reused in other funding allocation schemes, their overall importance to the Flemish universities is substantial. 展开更多
关键词 Performance-based research funding systems Flanders(Belgium) Norwegian model Web of Science VABB-SHW
下载PDF
Multi-agent Based Hierarchy Simulation Models of Carrier-based Aircraft Catapult Launch 被引量:18
16
作者 王维军 屈香菊 郭林亮 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2008年第3期223-231,共9页
With the aid of multi-agent based modeling approach to complex systems, the hierarchy simulation models of carrier-based aircraft catapult launch are developed. Ocean, carrier, aircraft, and atmosphere are treated as ... With the aid of multi-agent based modeling approach to complex systems, the hierarchy simulation models of carrier-based aircraft catapult launch are developed. Ocean, carrier, aircraft, and atmosphere are treated as aggregation agents, the detailed components like catapult, landing gears, and disturbances are considered as meta-agents, which belong to their aggregation agent. Thus, the model with two layers is formed i.e. the aggregation agent layer and the meta-agent layer. The information communication among all agents is described. The meta-agents within one aggregation agent communicate with each other directly by information sharing, but the meta-agents, which belong to different aggregation agents exchange their information through the aggregation layer first, and then perceive it from the sharing environment, that is the aggregation agent. Thus, not only the hierarchy model is built, but also the environment perceived by each agent is specified. Meanwhile, the problem of balancing the independency of agent and the resource consumption brought by real-time communication within multi-agent system (MAS) is resolved. Each agent involved in carrier-based aircraft catapult launch is depicted, with considering the interaction within disturbed atmospheric environment and multiple motion bodies including carrier, aircraft, and landing gears. The models of reactive agents among them are derived based on tensors, and the perceived messages and inner frameworks of each agent are characterized. Finally, some results of a simulation instance are given. The simulation and modeling of dynamic system based on multi-agent system is of benefit to express physical concepts and logical hierarchy clearly and precisely. The system model can easily draw in kinds of other agents to achieve a precise simulation of more complex system. This modeling technique makes the complex integral dynamic equations of multibodies decompose into parallel operations of single agent, and it is convenient to expand, maintain, and reuse the program codes. 展开更多
关键词 multi-agent system (MAS) multi-agent based modeling (MABM) TENSOR carrier-based aircraft catapult launch hierarchy simulation model
下载PDF
Reliability Evaluation Optimal Selection Model of Component-Based System
17
作者 Guo Yong Wan Tian Tian +1 位作者 Ma Pei Jun Su Xiao Hong 《Journal of Software Engineering and Applications》 2011年第7期433-441,共9页
If the components in a component-based software system come from different sources, the characteristics of the components may be different. Therefore, evaluating the reliability of a component-based system with a fixe... If the components in a component-based software system come from different sources, the characteristics of the components may be different. Therefore, evaluating the reliability of a component-based system with a fixed model for all components will not be reasonable. To solve this problem, this paper combines a single reliability growth model with an architecture-based reliability model, and proposes an optimal selecting approach. First, the most appropriate model of each component is selected according to the historical reliability data of the component, so that the evaluation deviation is the smallest. Then, system reliability is evaluated according to both the relationships among components and the using frequency of each component. As the approach takes into account the historical data and the using frequency of each component, the evaluation and prediction results are more accurate than those of using a single model. 展开更多
关键词 OPTIMAL EVALUATION Approach LIKELIHOOD Estimation Reliability EVALUATION COMPONENT-baseD system OPTIMAL SELECTION model (OSM)
下载PDF
Thermodynamic modeling of the La-Mg-Y system and Mg-based alloys database 被引量:2
18
作者 DU Zhenmin GUO Cuiping LI Changrong ZHANG Weijing 《Rare Metals》 SCIE EI CAS CSCD 2006年第5期492-500,共9页
As an example of the La-Mg-Y system, the method how to set up the themaodynamic model of individual phases was introduced in the process of thermodynamic optimization. The solution phases (liquid, body-centered cubic... As an example of the La-Mg-Y system, the method how to set up the themaodynamic model of individual phases was introduced in the process of thermodynamic optimization. The solution phases (liquid, body-centered cubic, face-centered cubic, hexagonal close-packed and double hexagonal close-packed) were modeled with the Redlich-Kister equation. The compound energy model has been used to describe the thermodynamic functions of the intermetallic compounds in the La-Mg-Y systems. The compounds Mg2Y, Mg24Y5, Mg12La, Mg17La2, Mg41Las, Mg3La and Mg2La in the La-Mg-Y system were treated as the formulae (Mg,Y)2(La,Mg,Y), Mg24(La,Mg,Y)4Y, Mg12(La, Y), Mg17(La,Y)2, Mg41(La,Y)5, Mg3(La,Mg,Y) and Mg2(La, Y), respectively. A model (La, Mg,Y)0.5(La,Mg,Y)0.5 was applied to describe the compound MgM formed by MgLa and MgY in order to cope with the order-disorder transition between body-centered cubic solution (A2) and MgM with CsCl-type structure (B2) in the La-Mg-Y system. The Gibbs energies of individual phases were optimized in the La-Mg, La-Y and La-Mg-Y systems by CALPHAD technique. The projection of the liquidus surfaces for the La-Mg-Y system was predicted. The Mg-based alloys database including 36 binary and 15 ternary systems formed by Mg, Al, Cu, Ni, Mn, Zn and rare earth elements was set up in SGTE standard. 展开更多
关键词 La-Mg-Y system thermodynamic modeling CALPHAD technique order-disorder transition Mg-based alloys database
下载PDF
Model Calculation of ln γ_i^0 for Solute Elements in Copper-base Alloy Systems
19
作者 王福明 李文超 +1 位作者 张宁欣 韩其勇 《Rare Metals》 SCIE EI CAS CSCD 1998年第4期48-53,共6页
A calculation formula of ln γ i 0 for solute element i in liquid alloys was derived by use of free volume theory and Miedema formation enthalpy model. The values of ln γ i 0 of solute elements in liqui... A calculation formula of ln γ i 0 for solute element i in liquid alloys was derived by use of free volume theory and Miedema formation enthalpy model. The values of ln γ i 0 of solute elements in liquid copper at 1273 K were obtained. The results obtained show that the coincidence rate of sign (positive or negative) was 90% for the calculated and experimental values, which were basically in the same magnitude. 展开更多
关键词 Free volume theory Miedema formation model Activity coefficient γ i 0 Copper base alloy system
下载PDF
Optimization of fault management system in power plants based on DD-RCM and TPN
20
作者 陈丽娟 杨欣 夏安邦 《Journal of Southeast University(English Edition)》 EI CAS 2006年第4期519-522,共4页
A method of optimizing the fault management system in power plants based on DD-RCM (resultchain based modeling for digital developing) and TPN (temporal Petri net) is proposed. First, the model of the fault manage... A method of optimizing the fault management system in power plants based on DD-RCM (resultchain based modeling for digital developing) and TPN (temporal Petri net) is proposed. First, the model of the fault management system was set using DD-RCM. Then, it was transformed to the temporal Petri net model by corresponding rules. Secondly, relationships among all the activities, such as choice, conflict, synchronization and concurrency, were confirmed according to the Petri net model and described employing the reengineering algorithm of incidence matrix. Thirdly, the Petri net model was reduced by combining reduction rules and conflict, synchronization relationships to optimize the fault management system in power plants. Finally, the functionality of the reduced net was proved by the temporal logic of the temporal Petri net. 展开更多
关键词 result-chain based modeling for digital developing (DD-RCM) temporal Petri net incidence matrix reduction rules
下载PDF
上一页 1 2 87 下一页 到第
使用帮助 返回顶部