This paper reviewed the trend and development of semi-solid metal technique. The processes and mechanisms for producing slurry of SSM and its industrial applications have been summarized and discussed. Discussions on ...This paper reviewed the trend and development of semi-solid metal technique. The processes and mechanisms for producing slurry of SSM and its industrial applications have been summarized and discussed. Discussions on the basic rheological theory are presented for more applications. Further consideration of the development and application of SSM technique is also proposed.展开更多
Concurrent engineering (CE) is a systematic approach to integrate concurrent design of products and their related processes. Its objective is to shorten product life cycle, improve product quality and reduce product c...Concurrent engineering (CE) is a systematic approach to integrate concurrent design of products and their related processes. Its objective is to shorten product life cycle, improve product quality and reduce product cost. Modeling the concurrent engineering product development process (CEPDP) is a key part of this process which has attracted the attention of researchers and engineers around the world. This paper focuses on a newly developed and potentially powerful CEPDP modeling philosophy——integrated multi view modeling (IMVM), by which managers can foresee the evolution of a product from its conception to its disposal and consider all the important factors in its production before a project is launched. CEPDP/IMVM is a product oriented modeling method. A modeling environment is used to establish a systematic model including different aspects of the process such as product information, development activities, enterprise resources, and organizational structure. The integration within an IMVM model should accurately reflect the PDPs dynamic characteristics and provide necessary information for monitoring and coordinating processes.展开更多
This article presents a multiscale simulation approach starting at the molecular level for the adsorption process development. A grand canonical Monte Carlo method is used for the prediction of adsorption isotherms of...This article presents a multiscale simulation approach starting at the molecular level for the adsorption process development. A grand canonical Monte Carlo method is used for the prediction of adsorption isotherms of methanol on an activated carbon at the molecular level. The adsorption isotherms obtained in the linear region （or adsorption constant） are exploited as a model parameter required for the adsorption process simulation. The adsorption process model described by a set of partial differential equations （PDEs） is solved by using the conservation element and solution element method, which produces a fast and an accurate numerical solution to PDEs. The simulation results obtained from the adsorption constant estimated at the molecular level are in good agreement with the experimental results of the pulse response. The systematical multiscale simulation approach addressed in this study may be useful to accelerate the adsorption process development by reducing the number of experiments.展开更多
China＇s reform and opening-up policy has brought the country a great development opportunity. The high-speed growth of the economy not only led China to a period of industrialization, urbanization, informatization an...China＇s reform and opening-up policy has brought the country a great development opportunity. The high-speed growth of the economy not only led China to a period of industrialization, urbanization, informatization and agricultural modernization, but also exacerbated the situation of the urban–rural dual structure. Based on the review of current studies, we first used the analytic hierarchy process（AHP） method to evaluate the urban–rural development and transformation level by population transformation index, land transformation index, industrial transformation index and social transformation index between 1996 and 2012 around the Bohai Rim Region. Then, based on the results of each index, we used the exploratory spatial data analysis（ESDA） method to investigate the spatial autocorrelation of the change in the urban–rural development transformation index during the 16-year period using Global Moran＇s I index and Local Moran＇s I index. Finally, we investigated the mechanism of change of the urban–rural development transformation index at county level, summarizing five main factors：（1） the radiation from the surrounding big cities,（2） the acceleration of the urbanization process,（3） the upgrading of the industrial structure,（4） the publishing and implementation of a macro development strategy and regional policy, and（5） natural factors such as topology.展开更多
Today the cycle time of the product develop is requ ir ed to be shortened. At the same time the requirement of the customers becomes mo re and more diverse and complex. The capability of the develop unit is limited b ...Today the cycle time of the product develop is requ ir ed to be shortened. At the same time the requirement of the customers becomes mo re and more diverse and complex. The capability of the develop unit is limited b ecause of the existence of heterogeneous systems and distributed environments. I n this paper, we bring forward a new approach to solve the problem in product de velopment process. We also settle part key technologies in it. A great deal of information from all kinds of sources in the distributed develop ment process is interweaved. The solution to organize the workflow and manage th e information in the process is called for anxiously. We use a new approach that is asynchronous and synchronous coupling product development approach based on the network. The approach extends the develop process from the time axis. Then t he activities in the process are organized from the asynchronous and synchronous aspects. The state of every activity projects at the ASN (active semantic netwo rk). The ASN includes decision system, intelligent agent, user interface and net work. The ASN decides the types and states of the activities and deals with the couple relationship among them. The knowledge stored in ASN is open to all users through the relative interfaces. Every specialist keeps contact with their user s relying on collaborative platform implements CSCW (computer support collaborat ive work) that integrated product/process design and development. The lack of gl obal communication in product development process can be prevented in the most d egree. The key technologies that exist in the asynchronous and synchronous coupling pro duct develop approach include: integrated development structure, orderly organiz ation of information, transparent management of process, agile transfer of infor mation and rapid prototype. The development process can be completed quickly by these technologies. The technologies involve wide content. In this paper, we dis cuss some key technologies. We validate the approach by the projectrapid response manufacturing a pplication in the distributed environment. The expensive device, high technology and low using lead to RE (Rapid engineering) and RP (Rapid prototype) service a pplication by the network. RE and RP develop rapidly due to the accelerated prod uct development process. RE and RP application service platform is built in the project.展开更多
Product development process management plays an important role in concurrent engineering (CE). The integration platform is a useful tool for effectively supporting the software development and integration. Based on th...Product development process management plays an important role in concurrent engineering (CE). The integration platform is a useful tool for effectively supporting the software development and integration. Based on the analysis of practical requirements for product development process management for CE, a CORBA-based integration platform of product development process management (IP-PDPM) is designed and developed. The design principles for IP-PDPM are described. The system architecture and functions of the platform are given, the key technologies for the implementation of IP-PDPM are presented, the application integration mechanism and its implementation techniques are also detailed.展开更多
The pharyngeal dental formula of Mylopharyngodon piceus is 4-5 as a rule, and the dentition isasymmetrical. It is difficult to identify each tooth in the larval dentition. In this paper the appearancepattem of tooth g...The pharyngeal dental formula of Mylopharyngodon piceus is 4-5 as a rule, and the dentition isasymmetrical. It is difficult to identify each tooth in the larval dentition. In this paper the appearancepattem of tooth germ with developmental process in this fish is described in detail. The formationpattern of the left dentition is contrasted with that of the right one. In the developmental process,the left pharyngeal dentition lacks teeth at position An3. Thus the left dentition is D-type as designatedby Nakajima(1984), while the right one is A-type.展开更多
A methodology is presented to identify environmental impact minimization alternatives for reaction processes and assess their environmental performance. The potential environmental impact (PEI) scheme can be used to v...A methodology is presented to identify environmental impact minimization alternatives for reaction processes and assess their environmental performance. The potential environmental impact (PEI) scheme can be used to visibly display the transformation relationships among different types of PEI, identify the sources of environmental impacts, and propose alternatives for eliminating or minimizing the impacts. To evaluate the environmental performance of the alternatives effectively, some new indices, such as PEI input rate of non-products, PEI output rate of non-products per profit and the PEI conversion efficiency are proposed. Finally, the application of the methodology is illustrated using an industrial case study.展开更多
DSS have high strength,high corrosion resistance and good welding properties.Comparing with the same corrosion resistance level austenitic stainless steel,DSS decrease largely Ni content and realize the thinning of th...DSS have high strength,high corrosion resistance and good welding properties.Comparing with the same corrosion resistance level austenitic stainless steel,DSS decrease largely Ni content and realize the thinning of thickness design to perfectly optimize properties and decrease costs.Now DSS have been widely used in many fields such as petroleum,chemical industry,paper production,shipbuilding,nuclear power,seawater desalting,vacuum salt production and architecture.Tisco have began the process development and product application research of DSS products from last century and gradually solved a lot of technical problems such as AOD nitrogen alloying control of various content DSS,high temperature deformation mechanism of thermal process,large deformation hot rolling process of coils,the effect of bad phase precipitated during hot treatment process on properties and high efficiency pickling of high Cr/Mo content DSS plates.The various alloy content DSS plates and wide cold rolling coils(3Re60,S32101,S32304,S31803,S32205,S32750 and SUS329J4L)were successfully developed and used in national important constructions,key industries and abroad projects.展开更多
1 Introduction The 21st century is coming and the world iron and steel making technology is facing an important technical evolution at this century turnover,which is reflected in two aspects:①Rapid development of tra...1 Introduction The 21st century is coming and the world iron and steel making technology is facing an important technical evolution at this century turnover,which is reflected in two aspects:①Rapid development of traditional iron&steel making technology with continuous regeneration;②Three major frontier techniques of metallurgy(smelting reduction;near-net-shape continuous展开更多
Since the launch of the economic reform and opening to the outside world, China has seen rapid growth in its export of mechanical and electrical products, with its export
Based on the analysis of the development process system status of domestic and foreign civil aircraft airborne system suppliers,this paper proposes the overall construction idea of"a set of civil aircraft process...Based on the analysis of the development process system status of domestic and foreign civil aircraft airborne system suppliers,this paper proposes the overall construction idea of"a set of civil aircraft process system"based on IPD(Integrated product development)in the organization.The development stage,process,activity and task are the logical framework elements of the system construction."Based on process decomposition,vertical stratification,horizontal segmentation,combination of special and common,process customized to tools,role and process integration,giving full consideration to the interface between supplier management and process modules"etc.are the concrete ideas.Moreover,formulate top⁃level system construction standards,implemented by process system management tool platform,so that the process system and development work can be effectively integrated to effectively guide the development work of airborne system suppliers,and meet the quality and airworthiness requirements of civil aircraft development.Through the development application of a certain type of flight control system,the process system and tool platform were verified and optimized in practice.展开更多
With the continuous development of science and technology, there will be greater breakthroughs in the field of aviation science and technology which also puts forward higher requirements for the project management of ...With the continuous development of science and technology, there will be greater breakthroughs in the field of aviation science and technology which also puts forward higher requirements for the project management of aviation product development. In recent years, with the gradual deepening of the aviation project management work research, many project management modes and project management methods have been gradually applied to the aviation product development project management work. Relevant staff needs to constantly improve their own quality, carefully formulate the project management methods and measures, form the aviation project management measures with their own development characteristics and promote the development of Chinas aviation industry.展开更多
Tsinghua-TOYO Research and Development Center of Magnesium and Aluminum Alloys Processing Technology was officially established between Tsinghua University and TOYO Machinery & Metal Co. on Feb. 26, 2002, which is...Tsinghua-TOYO Research and Development Center of Magnesium and Aluminum Alloys Processing Technology was officially established between Tsinghua University and TOYO Machinery & Metal Co. on Feb. 26, 2002, which is a non-independent legal research organization located in Department of Mechanical Engineering of Tsinghua University. The center was equipped with one set of 650t automatic magnesium and aluminum alloys diecasting machine and necessary accessories including the melting furnaces for magnesium alloys and aluminum alloys, an accurate magnesium pump to transfer the magnesium alloys to the shot sleeve of the die casting machine, a die temperature controller, and data logging systems for cavity pressure and die temperature distributions, etc. The center is aimed to the research and development of magnesium and aluminum die casting process and their related technologies, and the main research contents include:展开更多
In recent years,automation has become a key focus in software development as organizations seek to improve efficiency and reduce time-to-market.The integration of artificial intelligence(AI)tools,particularly those us...In recent years,automation has become a key focus in software development as organizations seek to improve efficiency and reduce time-to-market.The integration of artificial intelligence(AI)tools,particularly those using natural language processing(NLP)like ChatGPT,has opened new possibilities for automating various stages of the development lifecycle.The primary objective of this study is to evaluate the effectiveness of ChatGPT in automating various phases of software development.An artificial intelligence(AI)tool was developed using the OpenAI—Application Programming Interface(API),incorporating two key functionalities:1)generating user stories based on case or process inputs,and 2)estimating the effort required to execute each user story.Additionally,ChatGPT was employed to generate application code.The AI tool was tested in three case studies,each explored under two different development strategies:a semi-automated process utilizing the AI tools and a traditional manual approach.The results demonstrated a significant reduction in total development time,ranging from 40%to 51%.However,it was observed that the generated content could be inaccurate and incomplete,necessitating review and debugging before being applied to projects.In conclusion,given the increasing shift towards automation in software engineering,further research is critical to enhance the efficiency and reliability of AI tools,particularly those that leverage natural language processing(NLP)technologies.展开更多
The implementation of product development process management (PDPM) is an effective means of developing products with higher quality in shorter lead time. It is argued in this paper that product, data, person and acti...The implementation of product development process management (PDPM) is an effective means of developing products with higher quality in shorter lead time. It is argued in this paper that product, data, person and activity are basic factors in PDPM With detailed analysis of these basic factors and their relations in product developmed process, all product development activities are considered as tasks and the management of product development process is regarded as the management of task execution A task decomposition based product development model is proposed with methods of constructing task relation matrix from layer model and constraint model resulted from task decomposition. An algorithm for constructing directed task graph is given and is used in the management of tasks. Finally, the usage and limitation of the proposed PDPM model is given with further work proposed.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
基金the National Natural Science foundation of China! (59995440)
文摘This paper reviewed the trend and development of semi-solid metal technique. The processes and mechanisms for producing slurry of SSM and its industrial applications have been summarized and discussed. Discussions on the basic rheological theory are presented for more applications. Further consideration of the development and application of SSM technique is also proposed.
文摘Concurrent engineering (CE) is a systematic approach to integrate concurrent design of products and their related processes. Its objective is to shorten product life cycle, improve product quality and reduce product cost. Modeling the concurrent engineering product development process (CEPDP) is a key part of this process which has attracted the attention of researchers and engineers around the world. This paper focuses on a newly developed and potentially powerful CEPDP modeling philosophy——integrated multi view modeling (IMVM), by which managers can foresee the evolution of a product from its conception to its disposal and consider all the important factors in its production before a project is launched. CEPDP/IMVM is a product oriented modeling method. A modeling environment is used to establish a systematic model including different aspects of the process such as product information, development activities, enterprise resources, and organizational structure. The integration within an IMVM model should accurately reflect the PDPs dynamic characteristics and provide necessary information for monitoring and coordinating processes.
基金the Basic Research Program of the Korea Science & Engineering Foundation (KoSEF, No. R01-2006-000-10786-0).
文摘This article presents a multiscale simulation approach starting at the molecular level for the adsorption process development. A grand canonical Monte Carlo method is used for the prediction of adsorption isotherms of methanol on an activated carbon at the molecular level. The adsorption isotherms obtained in the linear region （or adsorption constant） are exploited as a model parameter required for the adsorption process simulation. The adsorption process model described by a set of partial differential equations （PDEs） is solved by using the conservation element and solution element method, which produces a fast and an accurate numerical solution to PDEs. The simulation results obtained from the adsorption constant estimated at the molecular level are in good agreement with the experimental results of the pulse response. The systematical multiscale simulation approach addressed in this study may be useful to accelerate the adsorption process development by reducing the number of experiments.
基金National Natural Science Foundation of China,No.41130748No.41471143
文摘China＇s reform and opening-up policy has brought the country a great development opportunity. The high-speed growth of the economy not only led China to a period of industrialization, urbanization, informatization and agricultural modernization, but also exacerbated the situation of the urban–rural dual structure. Based on the review of current studies, we first used the analytic hierarchy process（AHP） method to evaluate the urban–rural development and transformation level by population transformation index, land transformation index, industrial transformation index and social transformation index between 1996 and 2012 around the Bohai Rim Region. Then, based on the results of each index, we used the exploratory spatial data analysis（ESDA） method to investigate the spatial autocorrelation of the change in the urban–rural development transformation index during the 16-year period using Global Moran＇s I index and Local Moran＇s I index. Finally, we investigated the mechanism of change of the urban–rural development transformation index at county level, summarizing five main factors：（1） the radiation from the surrounding big cities,（2） the acceleration of the urbanization process,（3） the upgrading of the industrial structure,（4） the publishing and implementation of a macro development strategy and regional policy, and（5） natural factors such as topology.
文摘Today the cycle time of the product develop is requ ir ed to be shortened. At the same time the requirement of the customers becomes mo re and more diverse and complex. The capability of the develop unit is limited b ecause of the existence of heterogeneous systems and distributed environments. I n this paper, we bring forward a new approach to solve the problem in product de velopment process. We also settle part key technologies in it. A great deal of information from all kinds of sources in the distributed develop ment process is interweaved. The solution to organize the workflow and manage th e information in the process is called for anxiously. We use a new approach that is asynchronous and synchronous coupling product development approach based on the network. The approach extends the develop process from the time axis. Then t he activities in the process are organized from the asynchronous and synchronous aspects. The state of every activity projects at the ASN (active semantic netwo rk). The ASN includes decision system, intelligent agent, user interface and net work. The ASN decides the types and states of the activities and deals with the couple relationship among them. The knowledge stored in ASN is open to all users through the relative interfaces. Every specialist keeps contact with their user s relying on collaborative platform implements CSCW (computer support collaborat ive work) that integrated product/process design and development. The lack of gl obal communication in product development process can be prevented in the most d egree. The key technologies that exist in the asynchronous and synchronous coupling pro duct develop approach include: integrated development structure, orderly organiz ation of information, transparent management of process, agile transfer of infor mation and rapid prototype. The development process can be completed quickly by these technologies. The technologies involve wide content. In this paper, we dis cuss some key technologies. We validate the approach by the projectrapid response manufacturing a pplication in the distributed environment. The expensive device, high technology and low using lead to RE (Rapid engineering) and RP (Rapid prototype) service a pplication by the network. RE and RP develop rapidly due to the accelerated prod uct development process. RE and RP application service platform is built in the project.
文摘Product development process management plays an important role in concurrent engineering (CE). The integration platform is a useful tool for effectively supporting the software development and integration. Based on the analysis of practical requirements for product development process management for CE, a CORBA-based integration platform of product development process management (IP-PDPM) is designed and developed. The design principles for IP-PDPM are described. The system architecture and functions of the platform are given, the key technologies for the implementation of IP-PDPM are presented, the application integration mechanism and its implementation techniques are also detailed.
基金This project was funded by the International Cooperation of japan-Chinathe National Natural Science Foundation of China
文摘The pharyngeal dental formula of Mylopharyngodon piceus is 4-5 as a rule, and the dentition isasymmetrical. It is difficult to identify each tooth in the larval dentition. In this paper the appearancepattem of tooth germ with developmental process in this fish is described in detail. The formationpattern of the left dentition is contrasted with that of the right one. In the developmental process,the left pharyngeal dentition lacks teeth at position An3. Thus the left dentition is D-type as designatedby Nakajima(1984), while the right one is A-type.
基金National Natural Science Foundation of China(No.20176045)Major State Basic Research Development Program(No.G20000263)
文摘A methodology is presented to identify environmental impact minimization alternatives for reaction processes and assess their environmental performance. The potential environmental impact (PEI) scheme can be used to visibly display the transformation relationships among different types of PEI, identify the sources of environmental impacts, and propose alternatives for eliminating or minimizing the impacts. To evaluate the environmental performance of the alternatives effectively, some new indices, such as PEI input rate of non-products, PEI output rate of non-products per profit and the PEI conversion efficiency are proposed. Finally, the application of the methodology is illustrated using an industrial case study.
文摘DSS have high strength,high corrosion resistance and good welding properties.Comparing with the same corrosion resistance level austenitic stainless steel,DSS decrease largely Ni content and realize the thinning of thickness design to perfectly optimize properties and decrease costs.Now DSS have been widely used in many fields such as petroleum,chemical industry,paper production,shipbuilding,nuclear power,seawater desalting,vacuum salt production and architecture.Tisco have began the process development and product application research of DSS products from last century and gradually solved a lot of technical problems such as AOD nitrogen alloying control of various content DSS,high temperature deformation mechanism of thermal process,large deformation hot rolling process of coils,the effect of bad phase precipitated during hot treatment process on properties and high efficiency pickling of high Cr/Mo content DSS plates.The various alloy content DSS plates and wide cold rolling coils(3Re60,S32101,S32304,S31803,S32205,S32750 and SUS329J4L)were successfully developed and used in national important constructions,key industries and abroad projects.
文摘1 Introduction The 21st century is coming and the world iron and steel making technology is facing an important technical evolution at this century turnover,which is reflected in two aspects:①Rapid development of traditional iron&steel making technology with continuous regeneration;②Three major frontier techniques of metallurgy(smelting reduction;near-net-shape continuous
文摘Since the launch of the economic reform and opening to the outside world, China has seen rapid growth in its export of mechanical and electrical products, with its export
文摘Based on the analysis of the development process system status of domestic and foreign civil aircraft airborne system suppliers,this paper proposes the overall construction idea of"a set of civil aircraft process system"based on IPD(Integrated product development)in the organization.The development stage,process,activity and task are the logical framework elements of the system construction."Based on process decomposition,vertical stratification,horizontal segmentation,combination of special and common,process customized to tools,role and process integration,giving full consideration to the interface between supplier management and process modules"etc.are the concrete ideas.Moreover,formulate top⁃level system construction standards,implemented by process system management tool platform,so that the process system and development work can be effectively integrated to effectively guide the development work of airborne system suppliers,and meet the quality and airworthiness requirements of civil aircraft development.Through the development application of a certain type of flight control system,the process system and tool platform were verified and optimized in practice.
文摘With the continuous development of science and technology, there will be greater breakthroughs in the field of aviation science and technology which also puts forward higher requirements for the project management of aviation product development. In recent years, with the gradual deepening of the aviation project management work research, many project management modes and project management methods have been gradually applied to the aviation product development project management work. Relevant staff needs to constantly improve their own quality, carefully formulate the project management methods and measures, form the aviation project management measures with their own development characteristics and promote the development of Chinas aviation industry.
文摘Tsinghua-TOYO Research and Development Center of Magnesium and Aluminum Alloys Processing Technology was officially established between Tsinghua University and TOYO Machinery & Metal Co. on Feb. 26, 2002, which is a non-independent legal research organization located in Department of Mechanical Engineering of Tsinghua University. The center was equipped with one set of 650t automatic magnesium and aluminum alloys diecasting machine and necessary accessories including the melting furnaces for magnesium alloys and aluminum alloys, an accurate magnesium pump to transfer the magnesium alloys to the shot sleeve of the die casting machine, a die temperature controller, and data logging systems for cavity pressure and die temperature distributions, etc. The center is aimed to the research and development of magnesium and aluminum die casting process and their related technologies, and the main research contents include:
文摘In recent years,automation has become a key focus in software development as organizations seek to improve efficiency and reduce time-to-market.The integration of artificial intelligence(AI)tools,particularly those using natural language processing(NLP)like ChatGPT,has opened new possibilities for automating various stages of the development lifecycle.The primary objective of this study is to evaluate the effectiveness of ChatGPT in automating various phases of software development.An artificial intelligence(AI)tool was developed using the OpenAI—Application Programming Interface(API),incorporating two key functionalities:1)generating user stories based on case or process inputs,and 2)estimating the effort required to execute each user story.Additionally,ChatGPT was employed to generate application code.The AI tool was tested in three case studies,each explored under two different development strategies:a semi-automated process utilizing the AI tools and a traditional manual approach.The results demonstrated a significant reduction in total development time,ranging from 40%to 51%.However,it was observed that the generated content could be inaccurate and incomplete,necessitating review and debugging before being applied to projects.In conclusion,given the increasing shift towards automation in software engineering,further research is critical to enhance the efficiency and reliability of AI tools,particularly those that leverage natural language processing(NLP)technologies.
文摘The implementation of product development process management (PDPM) is an effective means of developing products with higher quality in shorter lead time. It is argued in this paper that product, data, person and activity are basic factors in PDPM With detailed analysis of these basic factors and their relations in product developmed process, all product development activities are considered as tasks and the management of product development process is regarded as the management of task execution A task decomposition based product development model is proposed with methods of constructing task relation matrix from layer model and constraint model resulted from task decomposition. An algorithm for constructing directed task graph is given and is used in the management of tasks. Finally, the usage and limitation of the proposed PDPM model is given with further work proposed.
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.
