The whole-process project cost management based on building information modeling(BIM)is a new management method,aiming to realize the comprehensive optimization and improvement of project cost management through the a...The whole-process project cost management based on building information modeling(BIM)is a new management method,aiming to realize the comprehensive optimization and improvement of project cost management through the application of BIM technology.This paper summarizes and analyzes the whole-process project cost management based on BIM,aiming to explore its application and development prospects in the construction industry.Firstly,this paper introduces the role and advantages of BIM technology in engineering cost management,including information integration,data sharing,and collaborative work.Secondly,the paper analyzes the key technologies and methods of the whole-process project cost management based on BIM,including model construction,data management,and cost control.In addition,the paper also discusses the challenges and limitations of the whole-process BIM project cost management,such as the inconsistency of technical standards,personnel training,and consciousness change.Finally,the paper summarizes the advantages and development prospects of the whole-process project cost management based on BIM and puts forward the direction and suggestions for future research.Through the research of this paper,it can provide a reference for construction cost management and promote innovation and development in the construction industry.展开更多
On the basis of PDM(product data management) definition and its connotation, the factors to ensure implementation success are analyzed. The definition phase, analysis phase, design phase, build and test phase, and pos...On the basis of PDM(product data management) definition and its connotation, the factors to ensure implementation success are analyzed. The definition phase, analysis phase, design phase, build and test phase, and post production phase during PDM implementation are described. The implementation is divided into ten processes, which consist of the above different phases. The relationships between phases and processes are illustrated. Finally, a workflow is proposed to guide the implementing at a fixed price.展开更多
The basic frame and the design idea of J2EE-based Product Data Management (PDM) system are presented. This paper adopts the technology of Object-Oriented to realize the database design and builds the information model...The basic frame and the design idea of J2EE-based Product Data Management (PDM) system are presented. This paper adopts the technology of Object-Oriented to realize the database design and builds the information model of this PDM system. The integration key technology of PDM and CAD systems are discussed, the isomerous interface characteristics between CAD and PDM systems are analyzed, and finally, the integration mode of the PDM and CAD systems is given. Using these technologies, the integration of PDM and CAD systems is realized and the consistence of data in PDM and CAD systems is kept. Finally, the Product Data Management system is developed, which has been tested on development process of the hydraulic generator. The running process is stable and safety.展开更多
A product data management system for a manufacturing enterprise is to make sure that the proper product data can be communicated to the right people at the right time.This paper describes a system analysis paradigm fo...A product data management system for a manufacturing enterprise is to make sure that the proper product data can be communicated to the right people at the right time.This paper describes a system analysis paradigm for data analysis in a product data management(PDM)development.Three aspects of the paradigm,i.e.,function,structure and behavior are rep- resented.The use of the paradigm explains why so many kinds of objects are necessary in a commercial database matrix and what models are available for developing a PDM application.As another result,a lot of models are derived from the analysis of product data system paradigm to model product data and PDM database definitions.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
PDM (product data management) is one kind of techniques based on software and database, which integrates information and process related to products. But it is not enough to perform the complication of PDM in enterpri...PDM (product data management) is one kind of techniques based on software and database, which integrates information and process related to products. But it is not enough to perform the complication of PDM in enterprises. Then the mechanism to harmonize all kinds of information and process is needed. The paper introduces a novel approach to implement the intelligent monitor of PDM based on MAS (multi agent system). It carries out the management of information and process by MC (monitor center). The paper first puts forward the architecture of the whole system, then defines the structure of MC and its interoperation mode.展开更多
The multidimensional analysis engine data management platform is constructed using big data distributed storage and parallel computing,data warehouse modeling technology,realizing the optimal management and instant qu...The multidimensional analysis engine data management platform is constructed using big data distributed storage and parallel computing,data warehouse modeling technology,realizing the optimal management and instant query of distributed oil and gas production dynamic big data.The centralized management and quick response of the production data of more than 36×10^4 oil,gas and water wells is realized.Multidimensional analysis subject model of oil,gas and water well production is built to pretreat the relevant data.At the level of China National Petroleum Corporation(CNPC),the rapid analysis and applications such as oil and gas production tracking,early production warning of key oilfields,analysis of low production wells and long shutdown wells,classification of reservoir development laws have been realized,and the processing time has been shortened from 1 d to 5 s.The basic unit of oil and gas production analysis is refined from oilfield to single well,making the production management more detailed.The process can be traced step by step according to CNPC,oil field company,field,block and single well,and the oil and gas production performance of each unit can be mastered in real time.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
A new web product data management architecture is presented. The three-tier web architecture and Simple Object Access Protocol (SOAP) are combined to build the web-based product data management (PDM) system which incl...A new web product data management architecture is presented. The three-tier web architecture and Simple Object Access Protocol (SOAP) are combined to build the web-based product data management (PDM) system which includes three tiers: the user services tier, the business services tier, and the data services tier. The client service component uses the server-side technology, and Extensible Markup Language (XML) web service which uses SOAP as the communication protocol is chosen as the business service component. To illustrate how to build a web-based PDM system using the proposed architecture, a case PDM system which included three logical tires was built. To use the security and central management features of the database, a stored procedure was recommended in the data services tier. The business object was implemented as an XML web service so that client could use standard internet protocols to communicate with the business object from any platform. In order to satisfy users using all sorts of browser, the server-side technology and Microsoft ASP.NET was used to create the dynamic user interface.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
This paper is concerned with the development of product data management (PDM) systems--WPDM systems based on web technologies. As a tool to integrate information, traditional PDM system has many benefits for the com...This paper is concerned with the development of product data management (PDM) systems--WPDM systems based on web technologies. As a tool to integrate information, traditional PDM system has many benefits for the companies in such aspects as improving design productivity, better control over projects and so on. With the maturing of web technologies, the advantages of WPDM system are obvious. We will show these advantages in detail in Part 3. WPDM system is built on three-tier application model to provide security and flexibility, they are back-end, middle layer and front-end. The basic designs in each layer will be briefly introduced in Part 4. In the future, WPDM will be extended to integrate with other applications to provide a complete web-based engineering environment.展开更多
The Three Gorges Hydropower Plant is the one with the largest installed capacity in the world today and has a decisive and important influence upon the security of the national power grids. It has been operated stably...The Three Gorges Hydropower Plant is the one with the largest installed capacity in the world today and has a decisive and important influence upon the security of the national power grids. It has been operated stably and supplied the East China, Central China, South China, Sichuan and Chongqing with clean renewable energy. This paper presents the management of the project’s dispatch, operation and maintenance and puts forward new ideas and new methods for the plant management, which may provide valuable references for the operation of oversized hydropower plants.展开更多
introduced are the main implementation contents and brought out is a cycle optimal PDMimplementation methodology by phases through studying requirements of enterprises' datamanagement and summarizing the existing ...introduced are the main implementation contents and brought out is a cycle optimal PDMimplementation methodology by phases through studying requirements of enterprises' datamanagement and summarizing the existing method. The implementation contents include documentsmanagement product structure and configuration management, product classification and codingmanagement, workflow management and software encapsulation. It divides the PDM implementationinto preparing, software selechon and training, implementation plan making, concrete implementingand evaluating. By the cycle of the last two pheses, the successful implementation of PDM can beobtained. This methodology has been used in the CIMS project of two companies and proved to bepractical.展开更多
An enhanced system architecture of Web-based product structure and configuration management system along with its, functions are is presented. The key techniques, such as construction of object models of product str...An enhanced system architecture of Web-based product structure and configuration management system along with its, functions are is presented. The key techniques, such as construction of object models of product structure and product configuration, hybrid approach method in product configuration management, sharing and integration of heterogeneous product data, integration with other sub-systems, are discussed too. A prototype system is developed by J2EE technology.展开更多
In concurrent engineering, effective process management is the key to improve the efficiency and quality of product development. Although in project management system, workflow management system and PDM system, proces...In concurrent engineering, effective process management is the key to improve the efficiency and quality of product development. Although in project management system, workflow management system and PDM system, process management functions are provided, they can not meet the needs of product development. In this paper, we integrate the project management, workflow management and product management technique together and a concurrent engineering oriented integrated product development process management system is proposed. The system structure, integrated product development model and running method are introduced. The practice proves this system is powerful in supporting product development process.展开更多
Background: Forest ecosystems are increasingly seen as multi-functional production systems, which should provide, besides timber and economic benefits, also other ecosystem services related to biological diversity, r...Background: Forest ecosystems are increasingly seen as multi-functional production systems, which should provide, besides timber and economic benefits, also other ecosystem services related to biological diversity, recreational uses and environmental functions of forests. This study analyzed the performance of even-aged rotation forest management (RFM), continuous cover forestry (CCF) and any-aged forestry (AAF) in the production of ecosystem services. AAF allows both even-aged and uneven-aged management schedules. The ecosystem services included in the analyses were net present value, volume of harvested timber, cowberry and bilberry yields, scenic value of the forest, carbon balance and suitability of the forest to Siberian jay. Methods: Data envelopment analysis was used to derive numerical efficiency ratios for the three management systems. Efficiency ratio is the sum of weighted outputs (ecosystem services) divided by the sum of weighted inputs. The linear programing model proposed by Charnes, Cooper and Rhodes was used to derive the weights for calculating efficiency scores for the silvicultural systems. Results and conclusions: CCF provided more ecosystem services than RFM, and CCF was more efficient than RFM and AAF in the production of ecosystem services. Multi-objective management provided more ecosystem services (except harvested timber) than single-objective management that maximized economic profitability. The use of low discount rate (resulting in low cutting level and high growing stock volume) led to better supply of most ecosystems services than the use of high discount rate. RFM where NPV was maximized with high discount rate led to particularly poor provision of most ecosystem services. In CCF the provision of ecosystem services was less sensitive to changes in discount rate and management objective than in RFM.展开更多
Based on the key function of version management in PDM system, this paper discusses the function and the realization of version management and the transitions of version states with a workflow. A directed aeyclic grap...Based on the key function of version management in PDM system, this paper discusses the function and the realization of version management and the transitions of version states with a workflow. A directed aeyclic graph is used to describe a version model. Three storage modes of the directed acyelic graph version model in the database, the bumping block and the PDM working memory are presented and the conversion principle of these three modes is given. The study indicates that building a dynamic product structure configuration model based on versions is the key to resolve the problem. Thus a version model of single product object is built. Then the version management model in product structure configuration is built and the application of version management of PDM syster is presented as a case.展开更多
Engineering Change (EC) management for a Product Lifecycle Management (PLM) system, including EC data model, EC evaluation and EC implementation is presented. A method of dynamic and parallel EC evaluation is proposed...Engineering Change (EC) management for a Product Lifecycle Management (PLM) system, including EC data model, EC evaluation and EC implementation is presented. A method of dynamic and parallel EC evaluation is proposed, which breaks an EC evaluation task into several subtasks. Such subtasks can be dynamically and simultaneously proceeded, disassembled and communicated by different specialists, and at the same time a set of EC objects is created. This approach provides flexible and effective evaluation of the EC. The EC implementation followed will further ensure the completeness and consistency of EC data.展开更多
In this paper,contribution of sources to the efficiency of Turkish investment trust companies is investigated by eight models which are constructed by different combinations of inputs of DEA analyze structure.Input or...In this paper,contribution of sources to the efficiency of Turkish investment trust companies is investigated by eight models which are constructed by different combinations of inputs of DEA analyze structure.Input oriented CRS based data envelopment analysis(DEA)and also Malmquist Productivity Index are applied for the time period of 2009—2016.Inputs of the CRS model are preferred as financial investments,cash and cash equivalents,cost of sales,and total sales while net profit and net sales are outputs of the models.It is reached at the conclusion that only management of investments is providing better results than only focusing on cash or cost management.In addition,effects and contribution of investment management parameter when it is added to the other ones is found more.展开更多
文摘The whole-process project cost management based on building information modeling(BIM)is a new management method,aiming to realize the comprehensive optimization and improvement of project cost management through the application of BIM technology.This paper summarizes and analyzes the whole-process project cost management based on BIM,aiming to explore its application and development prospects in the construction industry.Firstly,this paper introduces the role and advantages of BIM technology in engineering cost management,including information integration,data sharing,and collaborative work.Secondly,the paper analyzes the key technologies and methods of the whole-process project cost management based on BIM,including model construction,data management,and cost control.In addition,the paper also discusses the challenges and limitations of the whole-process BIM project cost management,such as the inconsistency of technical standards,personnel training,and consciousness change.Finally,the paper summarizes the advantages and development prospects of the whole-process project cost management based on BIM and puts forward the direction and suggestions for future research.Through the research of this paper,it can provide a reference for construction cost management and promote innovation and development in the construction industry.
文摘On the basis of PDM(product data management) definition and its connotation, the factors to ensure implementation success are analyzed. The definition phase, analysis phase, design phase, build and test phase, and post production phase during PDM implementation are described. The implementation is divided into ten processes, which consist of the above different phases. The relationships between phases and processes are illustrated. Finally, a workflow is proposed to guide the implementing at a fixed price.
基金Sponsored by Scientific Technology Development Project of Heilongjiang (Grant No.WH05A01) and Scientific Research Foundation of Harbin Institute of Technology(Grant No.HIT.MD2003.21).
文摘The basic frame and the design idea of J2EE-based Product Data Management (PDM) system are presented. This paper adopts the technology of Object-Oriented to realize the database design and builds the information model of this PDM system. The integration key technology of PDM and CAD systems are discussed, the isomerous interface characteristics between CAD and PDM systems are analyzed, and finally, the integration mode of the PDM and CAD systems is given. Using these technologies, the integration of PDM and CAD systems is realized and the consistence of data in PDM and CAD systems is kept. Finally, the Product Data Management system is developed, which has been tested on development process of the hydraulic generator. The running process is stable and safety.
文摘A product data management system for a manufacturing enterprise is to make sure that the proper product data can be communicated to the right people at the right time.This paper describes a system analysis paradigm for data analysis in a product data management(PDM)development.Three aspects of the paradigm,i.e.,function,structure and behavior are rep- resented.The use of the paradigm explains why so many kinds of objects are necessary in a commercial database matrix and what models are available for developing a PDM application.As another result,a lot of models are derived from the analysis of product data system paradigm to model product data and PDM database definitions.
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PDM (product data management) is one kind of techniques based on software and database, which integrates information and process related to products. But it is not enough to perform the complication of PDM in enterprises. Then the mechanism to harmonize all kinds of information and process is needed. The paper introduces a novel approach to implement the intelligent monitor of PDM based on MAS (multi agent system). It carries out the management of information and process by MC (monitor center). The paper first puts forward the architecture of the whole system, then defines the structure of MC and its interoperation mode.
基金Supported by the China National Science and Technology Major Project(2016ZX05016-006).
文摘The multidimensional analysis engine data management platform is constructed using big data distributed storage and parallel computing,data warehouse modeling technology,realizing the optimal management and instant query of distributed oil and gas production dynamic big data.The centralized management and quick response of the production data of more than 36×10^4 oil,gas and water wells is realized.Multidimensional analysis subject model of oil,gas and water well production is built to pretreat the relevant data.At the level of China National Petroleum Corporation(CNPC),the rapid analysis and applications such as oil and gas production tracking,early production warning of key oilfields,analysis of low production wells and long shutdown wells,classification of reservoir development laws have been realized,and the processing time has been shortened from 1 d to 5 s.The basic unit of oil and gas production analysis is refined from oilfield to single well,making the production management more detailed.The process can be traced step by step according to CNPC,oil field company,field,block and single well,and the oil and gas production performance of each unit can be mastered in real time.
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.
基金the National Key Project Foundation of China (No. 2001BA201A0605) and partially supported by the State Key Lab for Mechanical Transmission..
文摘A new web product data management architecture is presented. The three-tier web architecture and Simple Object Access Protocol (SOAP) are combined to build the web-based product data management (PDM) system which includes three tiers: the user services tier, the business services tier, and the data services tier. The client service component uses the server-side technology, and Extensible Markup Language (XML) web service which uses SOAP as the communication protocol is chosen as the business service component. To illustrate how to build a web-based PDM system using the proposed architecture, a case PDM system which included three logical tires was built. To use the security and central management features of the database, a stored procedure was recommended in the data services tier. The business object was implemented as an XML web service so that client could use standard internet protocols to communicate with the business object from any platform. In order to satisfy users using all sorts of browser, the server-side technology and Microsoft ASP.NET was used to create the dynamic user interface.
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This paper is concerned with the development of product data management (PDM) systems--WPDM systems based on web technologies. As a tool to integrate information, traditional PDM system has many benefits for the companies in such aspects as improving design productivity, better control over projects and so on. With the maturing of web technologies, the advantages of WPDM system are obvious. We will show these advantages in detail in Part 3. WPDM system is built on three-tier application model to provide security and flexibility, they are back-end, middle layer and front-end. The basic designs in each layer will be briefly introduced in Part 4. In the future, WPDM will be extended to integrate with other applications to provide a complete web-based engineering environment.
文摘The Three Gorges Hydropower Plant is the one with the largest installed capacity in the world today and has a decisive and important influence upon the security of the national power grids. It has been operated stably and supplied the East China, Central China, South China, Sichuan and Chongqing with clean renewable energy. This paper presents the management of the project’s dispatch, operation and maintenance and puts forward new ideas and new methods for the plant management, which may provide valuable references for the operation of oversized hydropower plants.
文摘introduced are the main implementation contents and brought out is a cycle optimal PDMimplementation methodology by phases through studying requirements of enterprises' datamanagement and summarizing the existing method. The implementation contents include documentsmanagement product structure and configuration management, product classification and codingmanagement, workflow management and software encapsulation. It divides the PDM implementationinto preparing, software selechon and training, implementation plan making, concrete implementingand evaluating. By the cycle of the last two pheses, the successful implementation of PDM can beobtained. This methodology has been used in the CIMS project of two companies and proved to bepractical.
基金Supported by the National High-Tech. R&D Program for CIMS China (Grant No. 2001AA412180)
文摘An enhanced system architecture of Web-based product structure and configuration management system along with its, functions are is presented. The key techniques, such as construction of object models of product structure and product configuration, hybrid approach method in product configuration management, sharing and integration of heterogeneous product data, integration with other sub-systems, are discussed too. A prototype system is developed by J2EE technology.
文摘In concurrent engineering, effective process management is the key to improve the efficiency and quality of product development. Although in project management system, workflow management system and PDM system, process management functions are provided, they can not meet the needs of product development. In this paper, we integrate the project management, workflow management and product management technique together and a concurrent engineering oriented integrated product development process management system is proposed. The system structure, integrated product development model and running method are introduced. The practice proves this system is powerful in supporting product development process.
文摘Background: Forest ecosystems are increasingly seen as multi-functional production systems, which should provide, besides timber and economic benefits, also other ecosystem services related to biological diversity, recreational uses and environmental functions of forests. This study analyzed the performance of even-aged rotation forest management (RFM), continuous cover forestry (CCF) and any-aged forestry (AAF) in the production of ecosystem services. AAF allows both even-aged and uneven-aged management schedules. The ecosystem services included in the analyses were net present value, volume of harvested timber, cowberry and bilberry yields, scenic value of the forest, carbon balance and suitability of the forest to Siberian jay. Methods: Data envelopment analysis was used to derive numerical efficiency ratios for the three management systems. Efficiency ratio is the sum of weighted outputs (ecosystem services) divided by the sum of weighted inputs. The linear programing model proposed by Charnes, Cooper and Rhodes was used to derive the weights for calculating efficiency scores for the silvicultural systems. Results and conclusions: CCF provided more ecosystem services than RFM, and CCF was more efficient than RFM and AAF in the production of ecosystem services. Multi-objective management provided more ecosystem services (except harvested timber) than single-objective management that maximized economic profitability. The use of low discount rate (resulting in low cutting level and high growing stock volume) led to better supply of most ecosystems services than the use of high discount rate. RFM where NPV was maximized with high discount rate led to particularly poor provision of most ecosystem services. In CCF the provision of ecosystem services was less sensitive to changes in discount rate and management objective than in RFM.
基金the Scientific Technology Development Project of Heilongjiang(Grant No.WH05A01 and GB05A103)Scientific Technology Development Project of Harbin
文摘Based on the key function of version management in PDM system, this paper discusses the function and the realization of version management and the transitions of version states with a workflow. A directed aeyclic graph is used to describe a version model. Three storage modes of the directed acyelic graph version model in the database, the bumping block and the PDM working memory are presented and the conversion principle of these three modes is given. The study indicates that building a dynamic product structure configuration model based on versions is the key to resolve the problem. Thus a version model of single product object is built. Then the version management model in product structure configuration is built and the application of version management of PDM syster is presented as a case.
基金Supported by Fujian Province Natural Science Foundation (A04400066)Xiamen Science and Technology Program(3502Z20055028)
文摘Engineering Change (EC) management for a Product Lifecycle Management (PLM) system, including EC data model, EC evaluation and EC implementation is presented. A method of dynamic and parallel EC evaluation is proposed, which breaks an EC evaluation task into several subtasks. Such subtasks can be dynamically and simultaneously proceeded, disassembled and communicated by different specialists, and at the same time a set of EC objects is created. This approach provides flexible and effective evaluation of the EC. The EC implementation followed will further ensure the completeness and consistency of EC data.
文摘In this paper,contribution of sources to the efficiency of Turkish investment trust companies is investigated by eight models which are constructed by different combinations of inputs of DEA analyze structure.Input oriented CRS based data envelopment analysis(DEA)and also Malmquist Productivity Index are applied for the time period of 2009—2016.Inputs of the CRS model are preferred as financial investments,cash and cash equivalents,cost of sales,and total sales while net profit and net sales are outputs of the models.It is reached at the conclusion that only management of investments is providing better results than only focusing on cash or cost management.In addition,effects and contribution of investment management parameter when it is added to the other ones is found more.