Dustin S. Birch, Jayesh B. Narsinghani, D. Herber, Thomas H. Bradley
An ongoing challenge within the field of Systems Engineering is the application of a right‐scoped and consistent approach to modeling human functions and risks within a system lifecycle. Humans interacting with a system can be modeled along a continuum from passive agents with not well‐defined interfaces with the system operations, to essential personnel who are responsible for dynamic interactions that ensure the safety and correct function of the system. This paper seeks to contribute to the integration of a model of human function, response, and reliability into the systems engineering of a complicated system through translation of a Human Factors Hazard Model (HFHM) into the Systems Modeling Language (SysML). The HFHM is constructed as a sequential event tree model of human response to triggering events, where each event's likelihood of failure is modeled by a set of fault trees predicting human failure probabilistically using Human Error Probabilities (HEP). Implementation of this model in SysML is demonstrated through a set of stereotyped structural, behavioral, and parametric diagrams. Integration of the HFHM within SysML demonstrates the benefits of human factors modeling and integration into Model‐Based Systems Engineering (MBSE) processes illustrating executability, reusability, and traceability.
{"title":"Human factors hazard modeling in the systems modeling language","authors":"Dustin S. Birch, Jayesh B. Narsinghani, D. Herber, Thomas H. Bradley","doi":"10.1002/sys.21659","DOIUrl":"https://doi.org/10.1002/sys.21659","url":null,"abstract":"An ongoing challenge within the field of Systems Engineering is the application of a right‐scoped and consistent approach to modeling human functions and risks within a system lifecycle. Humans interacting with a system can be modeled along a continuum from passive agents with not well‐defined interfaces with the system operations, to essential personnel who are responsible for dynamic interactions that ensure the safety and correct function of the system. This paper seeks to contribute to the integration of a model of human function, response, and reliability into the systems engineering of a complicated system through translation of a Human Factors Hazard Model (HFHM) into the Systems Modeling Language (SysML). The HFHM is constructed as a sequential event tree model of human response to triggering events, where each event's likelihood of failure is modeled by a set of fault trees predicting human failure probabilistically using Human Error Probabilities (HEP). Implementation of this model in SysML is demonstrated through a set of stereotyped structural, behavioral, and parametric diagrams. Integration of the HFHM within SysML demonstrates the benefits of human factors modeling and integration into Model‐Based Systems Engineering (MBSE) processes illustrating executability, reusability, and traceability.","PeriodicalId":54439,"journal":{"name":"Systems Engineering","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43150022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cost overruns averaging 45%–50% can occur during the acquisition process of large‐scale complex space programs. The factors that impact the cost overrun are frequently misunderstood and are not identified correctly. This paper investigates the impact of the parameters on the overall cost of a geosynchronous communication satellite program using model‐based global sensitivity analysis. A simulation model with the acquisition data was used to identify the key parameters within the system model that interact with the cost of the program. A system simulation model containing a physics‐based satellite model and a parametric cost model is utilized to conduct variance‐based sensitivity analysis. Data from selected acquisition reports are used to validate the system simulation model. Sobol' analysis is performed on the parameters associated with requirements of the satellite system, operations, and support to maintain the system, including the launch system and ground equipment. The results show that parameters related to the system‐based requirements significantly impact the program cost. These critical parameters, which influence the cost, lay the foundation to quantify the impact of system parameters and their uncertainty on the cost of the system using a simulation‐based model which will aid in the reduction of cost overruns during the design and development of future large‐scale complex engineered systems.
{"title":"Identifying key parameters impacting cost in large‐scale complex space programs using simulation‐based global sensitivity analysis","authors":"N. S. Basha, Leifur Þ. Leifsson, C. Bloebaum","doi":"10.1002/sys.21656","DOIUrl":"https://doi.org/10.1002/sys.21656","url":null,"abstract":"Cost overruns averaging 45%–50% can occur during the acquisition process of large‐scale complex space programs. The factors that impact the cost overrun are frequently misunderstood and are not identified correctly. This paper investigates the impact of the parameters on the overall cost of a geosynchronous communication satellite program using model‐based global sensitivity analysis. A simulation model with the acquisition data was used to identify the key parameters within the system model that interact with the cost of the program. A system simulation model containing a physics‐based satellite model and a parametric cost model is utilized to conduct variance‐based sensitivity analysis. Data from selected acquisition reports are used to validate the system simulation model. Sobol' analysis is performed on the parameters associated with requirements of the satellite system, operations, and support to maintain the system, including the launch system and ground equipment. The results show that parameters related to the system‐based requirements significantly impact the program cost. These critical parameters, which influence the cost, lay the foundation to quantify the impact of system parameters and their uncertainty on the cost of the system using a simulation‐based model which will aid in the reduction of cost overruns during the design and development of future large‐scale complex engineered systems.","PeriodicalId":54439,"journal":{"name":"Systems Engineering","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47724553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Laux, Kathryn C. Seigfried-Spellar, Laura Martínez Guerra, Gianna S. Lint
Sex trafficking is the fastest‐growing organized criminal activity. Trafficking organizations are driven by profit and provide a service due to existing demand. We examined the feasibility of applying risk assessment methods to understand the problem of sex trafficking from a systems perspective. Focusing on Indiana, we recruited and trained subject matter experts (SMEs) in risk assessment methodologies utilized in Six Sigma (SS); specifically Cause and Effect (C&E) Matrix and Failure Mode and Effects Analysis (FMEA). The research team developed a sex trafficking business process map (BPM) and prioritized activities by applying a C&E Matrix to identify the process steps with the potential for disruption. The most common failure modes (FMEA) identified by the SMEs included the trafficker or customer being caught followed by the victim being rescued. We conclude that an SS risk assessment approach is a viable framework in understanding the system of sex trafficking. Limitations and future research suggestions are discussed.
{"title":"Applying risk assessment methods to the sex trafficking process: A feasibility study","authors":"C. Laux, Kathryn C. Seigfried-Spellar, Laura Martínez Guerra, Gianna S. Lint","doi":"10.1002/sys.21658","DOIUrl":"https://doi.org/10.1002/sys.21658","url":null,"abstract":"Sex trafficking is the fastest‐growing organized criminal activity. Trafficking organizations are driven by profit and provide a service due to existing demand. We examined the feasibility of applying risk assessment methods to understand the problem of sex trafficking from a systems perspective. Focusing on Indiana, we recruited and trained subject matter experts (SMEs) in risk assessment methodologies utilized in Six Sigma (SS); specifically Cause and Effect (C&E) Matrix and Failure Mode and Effects Analysis (FMEA). The research team developed a sex trafficking business process map (BPM) and prioritized activities by applying a C&E Matrix to identify the process steps with the potential for disruption. The most common failure modes (FMEA) identified by the SMEs included the trafficker or customer being caught followed by the victim being rescued. We conclude that an SS risk assessment approach is a viable framework in understanding the system of sex trafficking. Limitations and future research suggestions are discussed.","PeriodicalId":54439,"journal":{"name":"Systems Engineering","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41728765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Karimaghaei, R. Cloutier, Aurangzeb Khan, J. Richardson, A. Phan
Currently, a wide range of newly designed devices are based on high‐end quantum technologies. To successfully design a quantum system, it is necessary to appropriately address the increasing complexity which exists in the development procedure of the system. A suitable approach to deal with this problem is to employ systems engineering models and integrate them with domain engineering tools. The model‐based systems engineering (MBSE) methodology is commonly used to analyze, design, manufacture, and test various complex systems. In this paper, the MBSE approach is chosen for the development of quantum dot solar cells as a typical quantum system and to deal with the complexity existing in this procedure. The analysis, manufacturing, and verification, validation, and testing (VV&T) for this system are described using SysML in Cameo Systems Modeler software to represent the role of models in this regard. Then a detailed design is performed in MATLAB and integrated with SysML to identify how changing various parameters during the system development process affects the overall system performance. This technique facilitates the communication between different engineering teams and helps to manage the complexity in the entire system lifecycle.
目前，许多新设计的器件都是基于高端量子技术。为了成功地设计量子系统，有必要适当地解决系统开发过程中日益复杂的问题。处理这个问题的合适方法是使用系统工程模型，并将它们与领域工程工具集成。基于模型的系统工程（MBSE）方法通常用于分析、设计、制造和测试各种复杂系统。本文选择MBSE方法来开发量子点太阳能电池作为一个典型的量子系统，并处理该过程中存在的复杂性。使用Cameo Systems Modeler软件中的SysML描述了该系统的分析、制造、验证、验证和测试（VV&T），以表示模型在这方面的作用。然后在MATLAB中进行详细设计，并与SysML集成，以确定系统开发过程中各种参数的变化如何影响系统的整体性能。这种技术有助于不同工程团队之间的沟通，并有助于管理整个系统生命周期中的复杂性。
{"title":"A model‐based systems engineering framework for quantum dot solar cells development","authors":"M. Karimaghaei, R. Cloutier, Aurangzeb Khan, J. Richardson, A. Phan","doi":"10.1002/sys.21655","DOIUrl":"https://doi.org/10.1002/sys.21655","url":null,"abstract":"Currently, a wide range of newly designed devices are based on high‐end quantum technologies. To successfully design a quantum system, it is necessary to appropriately address the increasing complexity which exists in the development procedure of the system. A suitable approach to deal with this problem is to employ systems engineering models and integrate them with domain engineering tools. The model‐based systems engineering (MBSE) methodology is commonly used to analyze, design, manufacture, and test various complex systems. In this paper, the MBSE approach is chosen for the development of quantum dot solar cells as a typical quantum system and to deal with the complexity existing in this procedure. The analysis, manufacturing, and verification, validation, and testing (VV&T) for this system are described using SysML in Cameo Systems Modeler software to represent the role of models in this regard. Then a detailed design is performed in MATLAB and integrated with SysML to identify how changing various parameters during the system development process affects the overall system performance. This technique facilitates the communication between different engineering teams and helps to manage the complexity in the entire system lifecycle.","PeriodicalId":54439,"journal":{"name":"Systems Engineering","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44679242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The public–private partnership (PPP) mode entails a variety of risks because the government, private enterprises, financial institutions, and other participants have different interests. To prevent private enterprise violations, dynamic government regulation of PPP risk‐sharing is necessary. Game theory is used here to examine the game behavior of government regulators, private enterprises, intermediary agencies, and the public in the stage of tracking management after the initial risk‐sharing of the project. Primarily, this study analyzes whether private enterprises provide fully compliant reporting and whether government departments check the information by investigating the behavioral motivations behind strategic choices. The primary contribution of this study was to construct a game model of government due diligence inspection under the condition of public participation in regulation. The results of simulations revealed the behavioral characteristics and stability of the participants of PPP in terms of decision‐making. Furthermore, a sensitivity analysis between the state variables and several auxiliary variables was used to reveal the internal relationships of the participants’ strategic choices. This paper offers new insights into reducing violation behavior, protecting the public interest from harm, reducing government departments’ regulatory costs, and promoting effective regulation with public participation.
{"title":"Game analysis of social capital violations and government regulation in public–private partnership risk sharing","authors":"Yan Li, Xinyu Wang","doi":"10.1002/sys.21657","DOIUrl":"https://doi.org/10.1002/sys.21657","url":null,"abstract":"The public–private partnership (PPP) mode entails a variety of risks because the government, private enterprises, financial institutions, and other participants have different interests. To prevent private enterprise violations, dynamic government regulation of PPP risk‐sharing is necessary. Game theory is used here to examine the game behavior of government regulators, private enterprises, intermediary agencies, and the public in the stage of tracking management after the initial risk‐sharing of the project. Primarily, this study analyzes whether private enterprises provide fully compliant reporting and whether government departments check the information by investigating the behavioral motivations behind strategic choices. The primary contribution of this study was to construct a game model of government due diligence inspection under the condition of public participation in regulation. The results of simulations revealed the behavioral characteristics and stability of the participants of PPP in terms of decision‐making. Furthermore, a sensitivity analysis between the state variables and several auxiliary variables was used to reveal the internal relationships of the participants’ strategic choices. This paper offers new insights into reducing violation behavior, protecting the public interest from harm, reducing government departments’ regulatory costs, and promoting effective regulation with public participation.","PeriodicalId":54439,"journal":{"name":"Systems Engineering","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45380510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohamed Elkamel Hamdane, Saad Harous, E. Kerkouche, Nabil Messaoudi
AADL—architecture analysis and design language—has proven to be important in developing real‐time embedded systems. However, its formalization capability is still limited, which makes it difficult to produce a consistent model; particularly, in the case where several models are combined together. Therefore, using formal verification is an effective way to meet the consistency requirements of the AADL model. This paper proposes a model‐based engineering approach that uses timed automata (TA) formalism to aggregate multiple AADL models into a single composite model. Based on the set of input AADL models, the proposed approach creates a consistent composed model as well as support model checking verification. The effectiveness of this contribution is evaluated through two case studies; a multicamera surveillance system and a drone system.
{"title":"Improving consistency of AADL models: A composition approach","authors":"Mohamed Elkamel Hamdane, Saad Harous, E. Kerkouche, Nabil Messaoudi","doi":"10.1002/sys.21653","DOIUrl":"https://doi.org/10.1002/sys.21653","url":null,"abstract":"AADL—architecture analysis and design language—has proven to be important in developing real‐time embedded systems. However, its formalization capability is still limited, which makes it difficult to produce a consistent model; particularly, in the case where several models are combined together. Therefore, using formal verification is an effective way to meet the consistency requirements of the AADL model. This paper proposes a model‐based engineering approach that uses timed automata (TA) formalism to aggregate multiple AADL models into a single composite model. Based on the set of input AADL models, the proposed approach creates a consistent composed model as well as support model checking verification. The effectiveness of this contribution is evaluated through two case studies; a multicamera surveillance system and a drone system.","PeriodicalId":54439,"journal":{"name":"Systems Engineering","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46328870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The methods and procedures within United States naval aviation to certify an aircraft safe for flight are well established. However, these methods and procedures are based on clearing a system that is operated or monitored by a human. A fully autonomous system will not have a human in or on the loop and will therefore require a new method for certifying it safe for flight. This paper details how to use run time assurance as the framework for a safety of flight certification of autonomous behavior within United States naval aviation. We present an aerial refueling task with run time assurance as use case for the framework for certification. Within the use case we then give more details on the mechanics of using RTA to enable autonomous functionality within naval aviation.
{"title":"Using a run time assurance approach for certifying autonomy within naval aviation","authors":"Donald H. Costello, Huan Xu","doi":"10.1002/sys.21654","DOIUrl":"https://doi.org/10.1002/sys.21654","url":null,"abstract":"The methods and procedures within United States naval aviation to certify an aircraft safe for flight are well established. However, these methods and procedures are based on clearing a system that is operated or monitored by a human. A fully autonomous system will not have a human in or on the loop and will therefore require a new method for certifying it safe for flight. This paper details how to use run time assurance as the framework for a safety of flight certification of autonomous behavior within United States naval aviation. We present an aerial refueling task with run time assurance as use case for the framework for certification. Within the use case we then give more details on the mechanics of using RTA to enable autonomous functionality within naval aviation.","PeriodicalId":54439,"journal":{"name":"Systems Engineering","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47900729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Karen V. Czachorowski, Cecilia Haskins, M. Mansouri
The offshore oil and gas upstream supply chain operations are part of a complex system with many stakeholders and intricate relationships. Traditionally, these operations are managed manually, which leads to inefficiencies. Despite the innovative and engineering‐orientated approaches adopted in other technical operations of the industry, the supply chain activities remain unchanged, relying heavily on legacy systems. However, cutting‐edge technology opportunities are available for adoption in supply chain management systems in the oil and gas industry. Such a transformative upgrade relies on first understanding the operational inefficiencies and preparing an accurate picture for how these operations should be performed. This study adopts a systemic approach to examine the oil and gas offshore supply chain operations of a case company to identify areas for improvement. The objective is to address the following research questions: (1) what is the current “AS‐IS” supply chain operations support; and (2) what is the desired “TO‐BE” state for these operations. This research adopts a soft systems lenses applied in an action research project to capture and analyze existing operations. The research revealed that information exchange is a major barrier, and that technology and organizational gaps are the primary hindrance for a digital transformation. The conclusion is that there is a need for a higher level of data exchange and increased data quality in any proposed transformation.
{"title":"Minding the gap between the front and back offices: A systemic analysis of the offshore oil and gas upstream supply chain for framing digital transformation","authors":"Karen V. Czachorowski, Cecilia Haskins, M. Mansouri","doi":"10.1002/sys.21652","DOIUrl":"https://doi.org/10.1002/sys.21652","url":null,"abstract":"The offshore oil and gas upstream supply chain operations are part of a complex system with many stakeholders and intricate relationships. Traditionally, these operations are managed manually, which leads to inefficiencies. Despite the innovative and engineering‐orientated approaches adopted in other technical operations of the industry, the supply chain activities remain unchanged, relying heavily on legacy systems. However, cutting‐edge technology opportunities are available for adoption in supply chain management systems in the oil and gas industry. Such a transformative upgrade relies on first understanding the operational inefficiencies and preparing an accurate picture for how these operations should be performed. This study adopts a systemic approach to examine the oil and gas offshore supply chain operations of a case company to identify areas for improvement. The objective is to address the following research questions: (1) what is the current “AS‐IS” supply chain operations support; and (2) what is the desired “TO‐BE” state for these operations. This research adopts a soft systems lenses applied in an action research project to capture and analyze existing operations. The research revealed that information exchange is a major barrier, and that technology and organizational gaps are the primary hindrance for a digital transformation. The conclusion is that there is a need for a higher level of data exchange and increased data quality in any proposed transformation.","PeriodicalId":54439,"journal":{"name":"Systems Engineering","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46644111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The increase in available data from sensors embedded in industrial equipment has led to a recent rise in the use of industrial predictive maintenance. In the aircraft industry, predictive maintenance has become an essential tool for optimizing maintenance schedules, reducing aircraft downtime, and identifying unexpected faults. Despite this, there is currently no comprehensive survey of predictive maintenance applications and techniques solely devoted to the aircraft manufacturing industry. This article is an in‐depth state‐of‐the‐art systematic literature review of the different data types, applications, projects, and opportunities for predictive maintenance in this industry. The goal of this review is to identify, and highlight the challenges and opportunities for future research in this field. This review found that the current focus of research is too biased towards aircraft engines due to a lack of publicly available data sets, and that greater automation is an important step to optimize aircraft maintenance to its full potential.
{"title":"Predictive maintenance analytics and implementation for aircraft: Challenges and opportunities","authors":"Izaak Stanton, K. Munir, Ahsan Ikram, M. El-Bakry","doi":"10.1002/sys.21651","DOIUrl":"https://doi.org/10.1002/sys.21651","url":null,"abstract":"The increase in available data from sensors embedded in industrial equipment has led to a recent rise in the use of industrial predictive maintenance. In the aircraft industry, predictive maintenance has become an essential tool for optimizing maintenance schedules, reducing aircraft downtime, and identifying unexpected faults. Despite this, there is currently no comprehensive survey of predictive maintenance applications and techniques solely devoted to the aircraft manufacturing industry. This article is an in‐depth state‐of‐the‐art systematic literature review of the different data types, applications, projects, and opportunities for predictive maintenance in this industry. The goal of this review is to identify, and highlight the challenges and opportunities for future research in this field. This review found that the current focus of research is too biased towards aircraft engines due to a lack of publicly available data sets, and that greater automation is an important step to optimize aircraft maintenance to its full potential.","PeriodicalId":54439,"journal":{"name":"Systems Engineering","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2022-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48717726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：