When designing large-sized complex machinery products, the design focus is always on the overall per- formance; however, there exist no design theory and method based on performance driven. In view of the defi- ciency...When designing large-sized complex machinery products, the design focus is always on the overall per- formance; however, there exist no design theory and method based on performance driven. In view of the defi- ciency of the existing design theory, according to the performance features of complex mechanical products, the performance indices are introduced into the traditional design theory of ＂Requirement-Function-Structure＂ to construct a new five-domain design theory of ＂Client Requirement-Function-Performance-Structure-Design Parameter＂. To support design practice based on this new theory, a product data model is established by using per- formance indices and the mapping relationship between them and the other four domains. When the product data model is applied to high-speed train design and combining the existing research result and relevant standards, the corresponding data model and its structure involving five domains of high-speed trains are established, which can provide technical support for studying the relationships between typical performance indices and design parame- ters and the fast achievement of a high-speed train scheme design. The five domains provide a reference for the design specification and evaluation criteria of high speed train and a new idea for the train＇s parameter design.展开更多
Product data management (PDM) has been accepted as an important tool for the manufacturing industries. In recent years, more and mor e researches have been conducted in the development of PDM. Their research area s in...Product data management (PDM) has been accepted as an important tool for the manufacturing industries. In recent years, more and mor e researches have been conducted in the development of PDM. Their research area s include system design, integration of object-oriented technology, data distri bution, collaborative and distributed manufacturing working environment, secur ity, and web-based integration. However, there are limitations on their rese arches. In particular, they cannot cater for PDM in distributed manufacturing e nvironment. This is especially true in South China, where many Hong Kong (HK) ma nufacturers have moved their production plants to different locations in Pearl R iver Delta for cost reduction. However, they retain their main offices in HK. Development of PDM system is inherently complex. Product related data cover prod uct name, product part number (product identification), drawings, material speci fications, dimension requirement, quality specification, test result, log size, production schedules, product data version and date of release, special tooling (e.g. jig and fixture), mould design, project engineering in charge, cost spread sheets, while process data includes engineering release, engineering change info rmation management, and other workflow related to the process information. Accor ding to Cornelissen et al., the contemporary PDM system should contains manageme nt functions in structure, retrieval, release, change, and workflow. In system design, development and implementation, a formal specification is nece ssary. However, there is no formal representation model for PDM system. Theref ore a graphical representation model is constructed to express the various scena rios of interactions between users and the PDM system. Statechart is then used to model the operations of PDM system, Fig.1. Statechart model bridges the curr ent gap between requirements, scenarios, and the initial design specifications o f PDM system. After properly analyzing the PDM system, a new distributed PDM (DPDM) system is proposed. Both graphical representation and statechart models are constructed f or the new DPDM system, Fig.2. New product data of DPDM and new system function s are then investigated to support product information flow in the new distribut ed environment. It is found that statecharts allow formal representations to capture the informa tion and control flows of both PDM and DPDM. In particular, statechart offers a dditional expressive power, when compared to conventional state transition diagr am, in terms of hierarchy, concurrency, history, and timing for DPDM behavioral modeling.展开更多
Before the implementation of product data management (PDM) system, person model and enterprise process model (EPM) must be firstly established. For the convenience of project management, all the related users must be ...Before the implementation of product data management (PDM) system, person model and enterprise process model (EPM) must be firstly established. For the convenience of project management, all the related users must be allocated to the “Person User Role Group” net. Based on the person model and the direction of information flow, the EPM is established subsequently. The EPM consists of several release levels, in which the access controls are defined. The EPM procedure shows the blueprint of the workflow process structure. The establishment of person model and EPM in an enterprise has been instanced at the end of this paper.展开更多
With the globalization and diversification of the market and the rapid development of Information Technology (IT) and Artificial Intelligence (AI),the digital revolution of manufacturing is coming.One of the key techn...With the globalization and diversification of the market and the rapid development of Information Technology (IT) and Artificial Intelligence (AI),the digital revolution of manufacturing is coming.One of the key technologies in digital manufacturing is product digital modeling.This paper firstly analyzes the information and features of the product digital model during each stage in the product whole lifecycle,then researches on the three critical technologies of digital modeling in digital man- ufacturing-product modeling,standard for the exchange of product model data and digital product data management.And the potential signification of the product digital model during the process of digital manufacturing is concluded-product digital model integrates primary features of each stage during the product whole lifecycle based on graphic features,applies STEP as data ex- change mechanism,and establishes PDM system to manage the large amount,complicated and dynamic product data to implement the product digital model data exchange,sharing and integration.展开更多
In this paper, an open architecture and its implementation for product data management are presented. The system architecture, product data definition model, and a set of components of the architecture are discussed i...In this paper, an open architecture and its implementation for product data management are presented. The system architecture, product data definition model, and a set of components of the architecture are discussed in detail. Especially, the principle and some mechanism of one of the components, an object oriented database management system GH-EODB, are discussed in more detail. The architecture is extensible and adaptable.展开更多
Tea is a very important cash crop in Rwanda, as it provides crucial income and employment for farmers in poor rural areas. From 2017 to 2020, this study was intended to determine the impact of seasonal rainfall on tea...Tea is a very important cash crop in Rwanda, as it provides crucial income and employment for farmers in poor rural areas. From 2017 to 2020, this study was intended to determine the impact of seasonal rainfall on tea output in Rwanda while still considering temperature, plot size (land), and fertiliser for tea plantations in three of Rwanda’s western, southern, and northern provinces, western province with “Gisovu” and “Nyabihu”, southern with “Kitabi”, and northern with “Mulindi” tea company. The study tested the level of statistical significance of all considered variables in different formulation of panel data models to assess individual behaviour of independent variables that would affect tea production. According to this study, a positive change in rainfall of 1 mm will increase tea production by 0.215 percentage points of tons of fresh leaves. Rainfall is a statistically significant variable among all variables with a positive impact on tea output Qitin Rwanda’s Western, Southern, and Northern provinces. Rainfall availability favourably affects tea output and supports our claim. Therefore, there is a need for collaboration efforts towards developing sustainable adaptation and mitigation options against climate change, targeting tea farming and the government to ensure that tea policy reforms are targeted towards raising the competitiveness of Rwandan tea at local and global market.展开更多
针对金刚石滚轮是一种回转体零件以及其加工制造过程中信息化集成程度低等特点,对金刚石滚轮的特征信息提取、特征加工方案决策、数控程序后置处理等关键技术进行了研究,采用了产品模型数据交换标准STEP AP 242,实现对金刚石滚轮的制造...针对金刚石滚轮是一种回转体零件以及其加工制造过程中信息化集成程度低等特点,对金刚石滚轮的特征信息提取、特征加工方案决策、数控程序后置处理等关键技术进行了研究,采用了产品模型数据交换标准STEP AP 242,实现对金刚石滚轮的制造特征信息提取,使用STEP AP 242和PDM相结合的集成方式,将金刚石滚轮三维模型作为制造加工信息的载体,并选择SolidWorks作为CAD和CAM软件,以及选择Aras Innovator作为PDM平台,使用C#编程语言和数据库技术开发了金刚石滚轮CAD/CAPP/CAM/PDM集成系统,并进行了实例验证。展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.51275432,51505390)Sichuan Application Foundation Projects(Grant No.2016JY0098)Independent Research Project of TPL(Grant No.TPL1501)
文摘When designing large-sized complex machinery products, the design focus is always on the overall per- formance; however, there exist no design theory and method based on performance driven. In view of the defi- ciency of the existing design theory, according to the performance features of complex mechanical products, the performance indices are introduced into the traditional design theory of ＂Requirement-Function-Structure＂ to construct a new five-domain design theory of ＂Client Requirement-Function-Performance-Structure-Design Parameter＂. To support design practice based on this new theory, a product data model is established by using per- formance indices and the mapping relationship between them and the other four domains. When the product data model is applied to high-speed train design and combining the existing research result and relevant standards, the corresponding data model and its structure involving five domains of high-speed trains are established, which can provide technical support for studying the relationships between typical performance indices and design parame- ters and the fast achievement of a high-speed train scheme design. The five domains provide a reference for the design specification and evaluation criteria of high speed train and a new idea for the train＇s parameter design.
文摘Product data management (PDM) has been accepted as an important tool for the manufacturing industries. In recent years, more and mor e researches have been conducted in the development of PDM. Their research area s include system design, integration of object-oriented technology, data distri bution, collaborative and distributed manufacturing working environment, secur ity, and web-based integration. However, there are limitations on their rese arches. In particular, they cannot cater for PDM in distributed manufacturing e nvironment. This is especially true in South China, where many Hong Kong (HK) ma nufacturers have moved their production plants to different locations in Pearl R iver Delta for cost reduction. However, they retain their main offices in HK. Development of PDM system is inherently complex. Product related data cover prod uct name, product part number (product identification), drawings, material speci fications, dimension requirement, quality specification, test result, log size, production schedules, product data version and date of release, special tooling (e.g. jig and fixture), mould design, project engineering in charge, cost spread sheets, while process data includes engineering release, engineering change info rmation management, and other workflow related to the process information. Accor ding to Cornelissen et al., the contemporary PDM system should contains manageme nt functions in structure, retrieval, release, change, and workflow. In system design, development and implementation, a formal specification is nece ssary. However, there is no formal representation model for PDM system. Theref ore a graphical representation model is constructed to express the various scena rios of interactions between users and the PDM system. Statechart is then used to model the operations of PDM system, Fig.1. Statechart model bridges the curr ent gap between requirements, scenarios, and the initial design specifications o f PDM system. After properly analyzing the PDM system, a new distributed PDM (DPDM) system is proposed. Both graphical representation and statechart models are constructed f or the new DPDM system, Fig.2. New product data of DPDM and new system function s are then investigated to support product information flow in the new distribut ed environment. It is found that statecharts allow formal representations to capture the informa tion and control flows of both PDM and DPDM. In particular, statechart offers a dditional expressive power, when compared to conventional state transition diagr am, in terms of hierarchy, concurrency, history, and timing for DPDM behavioral modeling.
文摘Before the implementation of product data management (PDM) system, person model and enterprise process model (EPM) must be firstly established. For the convenience of project management, all the related users must be allocated to the “Person User Role Group” net. Based on the person model and the direction of information flow, the EPM is established subsequently. The EPM consists of several release levels, in which the access controls are defined. The EPM procedure shows the blueprint of the workflow process structure. The establishment of person model and EPM in an enterprise has been instanced at the end of this paper.
文摘With the globalization and diversification of the market and the rapid development of Information Technology (IT) and Artificial Intelligence (AI),the digital revolution of manufacturing is coming.One of the key technologies in digital manufacturing is product digital modeling.This paper firstly analyzes the information and features of the product digital model during each stage in the product whole lifecycle,then researches on the three critical technologies of digital modeling in digital man- ufacturing-product modeling,standard for the exchange of product model data and digital product data management.And the potential signification of the product digital model during the process of digital manufacturing is concluded-product digital model integrates primary features of each stage during the product whole lifecycle based on graphic features,applies STEP as data ex- change mechanism,and establishes PDM system to manage the large amount,complicated and dynamic product data to implement the product digital model data exchange,sharing and integration.
基金the High Technoloey Research and Development Programme of China
文摘In this paper, an open architecture and its implementation for product data management are presented. The system architecture, product data definition model, and a set of components of the architecture are discussed in detail. Especially, the principle and some mechanism of one of the components, an object oriented database management system GH-EODB, are discussed in more detail. The architecture is extensible and adaptable.
文摘Tea is a very important cash crop in Rwanda, as it provides crucial income and employment for farmers in poor rural areas. From 2017 to 2020, this study was intended to determine the impact of seasonal rainfall on tea output in Rwanda while still considering temperature, plot size (land), and fertiliser for tea plantations in three of Rwanda’s western, southern, and northern provinces, western province with “Gisovu” and “Nyabihu”, southern with “Kitabi”, and northern with “Mulindi” tea company. The study tested the level of statistical significance of all considered variables in different formulation of panel data models to assess individual behaviour of independent variables that would affect tea production. According to this study, a positive change in rainfall of 1 mm will increase tea production by 0.215 percentage points of tons of fresh leaves. Rainfall is a statistically significant variable among all variables with a positive impact on tea output Qitin Rwanda’s Western, Southern, and Northern provinces. Rainfall availability favourably affects tea output and supports our claim. Therefore, there is a need for collaboration efforts towards developing sustainable adaptation and mitigation options against climate change, targeting tea farming and the government to ensure that tea policy reforms are targeted towards raising the competitiveness of Rwandan tea at local and global market.
文摘针对金刚石滚轮是一种回转体零件以及其加工制造过程中信息化集成程度低等特点,对金刚石滚轮的特征信息提取、特征加工方案决策、数控程序后置处理等关键技术进行了研究,采用了产品模型数据交换标准STEP AP 242,实现对金刚石滚轮的制造特征信息提取,使用STEP AP 242和PDM相结合的集成方式,将金刚石滚轮三维模型作为制造加工信息的载体,并选择SolidWorks作为CAD和CAM软件,以及选择Aras Innovator作为PDM平台,使用C#编程语言和数据库技术开发了金刚石滚轮CAD/CAPP/CAM/PDM集成系统,并进行了实例验证。
