Features are commonly used to describe functional and nonfunctional aspects of software. To effectively evolve and reuse features, their location in software assets has to be known. However, locating features is often difficult given their crosscutting nature. Once implemented, the knowledge about a feature's location quickly deteriorates, requiring expensive recovering of these locations. Manually recording and maintaining traceability information is generally considered expensive and error-prone. In this paper, we argue to the contrary and hypothesize that such information can be effectively embedded into software assets, and that arising costs will be amortized by the benefits of this information later during development. We test this hypothesis in a study where we simulate the development of a product line of cloned/forked projects using a lightweight code annotation approach. We identify annotation evolution patterns and measure the cost and benefit of these annotations. Our results show that not only the cost of adding annotations, but also that of maintaining them is small compared to the actual development cost. Embedding the annotations into assets significantly reduced the maintenance cost because they naturally co-evolve with the assets. Our results also show that a majority of these annotations provides a benefit for feature-related code maintenance tasks, such as feature propagation and migrating clones into a platform.
{"title":"Maintaining feature traceability with embedded annotations","authors":"Wenbin Ji, T. Berger, M. Antkiewicz, K. Czarnecki","doi":"10.1145/2791060.2791107","DOIUrl":"https://doi.org/10.1145/2791060.2791107","url":null,"abstract":"Features are commonly used to describe functional and nonfunctional aspects of software. To effectively evolve and reuse features, their location in software assets has to be known. However, locating features is often difficult given their crosscutting nature. Once implemented, the knowledge about a feature's location quickly deteriorates, requiring expensive recovering of these locations. Manually recording and maintaining traceability information is generally considered expensive and error-prone. In this paper, we argue to the contrary and hypothesize that such information can be effectively embedded into software assets, and that arising costs will be amortized by the benefits of this information later during development. We test this hypothesis in a study where we simulate the development of a product line of cloned/forked projects using a lightweight code annotation approach. We identify annotation evolution patterns and measure the cost and benefit of these annotations. Our results show that not only the cost of adding annotations, but also that of maintaining them is small compared to the actual development cost. Embedding the annotations into assets significantly reduced the maintenance cost because they naturally co-evolve with the assets. Our results also show that a majority of these annotations provides a benefit for feature-related code maintenance tasks, such as feature propagation and migrating clones into a platform.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130061571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The EASy-Producer product line environment is a novel open-source tool that supports the lightweight engineering of software product lines and variability-rich software ecosystems. It has been applied in several industrial case studies, showing its practical applicability both from a stability and a capability point of view. The tool set integrates both, interactive configuration capabilities and a DSL-based approach to variability modeling, configuration definition and product derivation. The goal of the tutorial is to provide the participants with an overview of the tool. However, the main focus will be on a brief introduction of the DSLs. After participating in the tutorial, the participants will understand the capabilities of the toolset and will have a basic practical understanding of how to use it to define software ecosystems and derive products from them.
{"title":"EASy-Producer: from product lines to variability-rich software ecosystems","authors":"Klaus Schmid, Holger Eichelberger","doi":"10.1145/2791060.2791112","DOIUrl":"https://doi.org/10.1145/2791060.2791112","url":null,"abstract":"The EASy-Producer product line environment is a novel open-source tool that supports the lightweight engineering of software product lines and variability-rich software ecosystems. It has been applied in several industrial case studies, showing its practical applicability both from a stability and a capability point of view. The tool set integrates both, interactive configuration capabilities and a DSL-based approach to variability modeling, configuration definition and product derivation. The goal of the tutorial is to provide the participants with an overview of the tool. However, the main focus will be on a brief introduction of the DSLs. After participating in the tutorial, the participants will understand the capabilities of the toolset and will have a basic practical understanding of how to use it to define software ecosystems and derive products from them.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123166911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mostly all innovative driving functions are realized by software and many of them are safety-related. This leads to an increasing complexity when analyzing, in respect to ISO 26262, the dependencies between functions in general as well as the functional or technical variance in particular. Major challenges arise while developing innovative automotive functions: (1) The increasing variety of development artifacts, (2) inconsistencies due to the integration of different models and data, (3) a high effort concerning traceability between various artifacts, and (4) finally the management of changes in these artifacts as well as the extensive reuse thereof. In this paper we propose a process for a model-based change impact analysis, which is already integrating well established engineering disciplines: model-based development, software product line engineering (SPLE) and safety engineering. With respect to change requests, a holistic handling of variants in a software product line (SPL) and its corresponding variability including safety artifacts are necessary to ensure an efficient development which complies with the automotive safety standard ISO 26262. In particular, we describe engineering tasks and preconditions to achieve a process to support an integrated change impact analysis. The assessment of the change impact is essential for a systematic reuse of safety-related engineering artifacts for different product variants. Thus, we achieve both, a decrease of development costs and an increase in quality of safety-critical innovative functions.
{"title":"A process to support a systematic change impact analysis of variability and safety in automotive functions","authors":"Michael Käßmeyer, M. Schulze, Markus Schurius","doi":"10.1145/2791060.2791079","DOIUrl":"https://doi.org/10.1145/2791060.2791079","url":null,"abstract":"Mostly all innovative driving functions are realized by software and many of them are safety-related. This leads to an increasing complexity when analyzing, in respect to ISO 26262, the dependencies between functions in general as well as the functional or technical variance in particular. Major challenges arise while developing innovative automotive functions: (1) The increasing variety of development artifacts, (2) inconsistencies due to the integration of different models and data, (3) a high effort concerning traceability between various artifacts, and (4) finally the management of changes in these artifacts as well as the extensive reuse thereof. In this paper we propose a process for a model-based change impact analysis, which is already integrating well established engineering disciplines: model-based development, software product line engineering (SPLE) and safety engineering. With respect to change requests, a holistic handling of variants in a software product line (SPL) and its corresponding variability including safety artifacts are necessary to ensure an efficient development which complies with the automotive safety standard ISO 26262. In particular, we describe engineering tasks and preconditions to achieve a process to support an integrated change impact analysis. The assessment of the change impact is essential for a systematic reuse of safety-related engineering artifacts for different product variants. Thus, we achieve both, a decrease of development costs and an increase in quality of safety-critical innovative functions.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130440660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The benefits offered by cloud technologies have compelled enterprises to adopt the Software-as-a-Service (SaaS) model for their enterprise software needs. A SaaS has to be configured or customized to suit the specific requirements of every enterprise that subscribes to it. IT service providers have to deal with the problem of testing many such configurations created for different enterprises. The software gets upgraded periodically and the configurations need to be tested on an ongoing basis to ensure business continuity. In order to run the testing organization efficiently, it is imperative that the test cycle is automated. Developing automated test scripts for a large number of configurations is a non-trivial task because differences across them may range from a few user interface changes to business process level changes. We propose an approach that combines the benefits of model driven engineering and variability modeling to address this issue. The approach comprises of the Enterprise Software Test Modeling Language to model the test cases. We use the Common Variability Language to model variability in the test cases and apply model transformations on a base model to generate a test model for each configuration. These models are used to generate automated test scripts for all the configurations. We describe the test modelling language and an experiment which shows that the approach can be used to automatically generate variations in automated test scripts.
{"title":"Automated testing of software-as-a-service configurations using a variability language","authors":"Sachin Patel, Vipul Shah","doi":"10.1145/2791060.2791072","DOIUrl":"https://doi.org/10.1145/2791060.2791072","url":null,"abstract":"The benefits offered by cloud technologies have compelled enterprises to adopt the Software-as-a-Service (SaaS) model for their enterprise software needs. A SaaS has to be configured or customized to suit the specific requirements of every enterprise that subscribes to it. IT service providers have to deal with the problem of testing many such configurations created for different enterprises. The software gets upgraded periodically and the configurations need to be tested on an ongoing basis to ensure business continuity. In order to run the testing organization efficiently, it is imperative that the test cycle is automated. Developing automated test scripts for a large number of configurations is a non-trivial task because differences across them may range from a few user interface changes to business process level changes. We propose an approach that combines the benefits of model driven engineering and variability modeling to address this issue. The approach comprises of the Enterprise Software Test Modeling Language to model the test cases. We use the Common Variability Language to model variability in the test cases and apply model transformations on a base model to generate a test model for each configuration. These models are used to generate automated test scripts for all the configurations. We describe the test modelling language and an experiment which shows that the approach can be used to automatically generate variations in automated test scripts.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132186273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The process of Developing Software Product Line Architectures can be a complex task. However, the use of Model Driven Engineering (MDE) techniques can facilitate the development of SPLAs by introducing Domain Specific Languages, Graphical Editors, and Generators. Together these are considered the sacred triad of MDE. Key to understanding MDE and how it fits into SPLAs is to know exactly what each part of the trinity means, how it relates to the other parts, and what the various implementations are for each. This tutorial has its foundations in years of industrial experience with large and complex SPLAs in various industries. This tutorial continues to be updated each year to include recent and critical innovations in MDE and SPL. This year will include information on key Model Transformation, Constraints and Textual Modeling Languages targeted at Software Product Lines. Additionally, it will cover advances in Software Product Line migration technologies which include techniques as to how to effectively migrate legacy systems toward and MDE/SPLA architecture and implementation. This year's tutorial includes extensive industrial experience on the testing of large and complex SPLAs. The goal of this tutorial is to educate attendees on what MDE technologies are, how exactly they relate synergistically to Software Product Line Architectures, and how to actually apply them using an existing Eclipse implementation.
{"title":"Leveraging model driven engineering in software product line architectures","authors":"B. Trask, Angel Roman","doi":"10.1109/SPLC.2008.64","DOIUrl":"https://doi.org/10.1109/SPLC.2008.64","url":null,"abstract":"The process of Developing Software Product Line Architectures can be a complex task. However, the use of Model Driven Engineering (MDE) techniques can facilitate the development of SPLAs by introducing Domain Specific Languages, Graphical Editors, and Generators. Together these are considered the sacred triad of MDE. Key to understanding MDE and how it fits into SPLAs is to know exactly what each part of the trinity means, how it relates to the other parts, and what the various implementations are for each. This tutorial has its foundations in years of industrial experience with large and complex SPLAs in various industries. This tutorial continues to be updated each year to include recent and critical innovations in MDE and SPL. This year will include information on key Model Transformation, Constraints and Textual Modeling Languages targeted at Software Product Lines. Additionally, it will cover advances in Software Product Line migration technologies which include techniques as to how to effectively migrate legacy systems toward and MDE/SPLA architecture and implementation. This year's tutorial includes extensive industrial experience on the testing of large and complex SPLAs. The goal of this tutorial is to educate attendees on what MDE technologies are, how exactly they relate synergistically to Software Product Line Architectures, and how to actually apply them using an existing Eclipse implementation.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115230877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One of the challenges of implementing a product line process is finding the appropriate tools for automation. One of our larger customers was implementing a product line process by-hand in a labor intensive and fragile way. We collaborated with them to evolve our distributed version control system, BitKeeper, into a tool that could handle their performance and product line requirements. The resulting product line generated several complex CPUs (around a billion transistors each). In this paper, we describe their by-hand process for producing different variations of a computer processor; we'll provide some background on the distributed version control system they were using; we'll describe the architectural changes implemented in BitKeeper for supporting product line work flows; we'll describe some of the changes we did to increase performance and provide some benchmark results comparing BitKeeper to Git, and we'll describe the work flow resulting from using the new architecture to replace their by-hand process. In the final section we'll discuss the current limitations of the existing tool, and describe how we plan on evolving it to overcome those limitations.
{"title":"Preliminary product line support in BitKeeper","authors":"Larry W. McVoy","doi":"10.1145/2791060.2791110","DOIUrl":"https://doi.org/10.1145/2791060.2791110","url":null,"abstract":"One of the challenges of implementing a product line process is finding the appropriate tools for automation. One of our larger customers was implementing a product line process by-hand in a labor intensive and fragile way. We collaborated with them to evolve our distributed version control system, BitKeeper, into a tool that could handle their performance and product line requirements. The resulting product line generated several complex CPUs (around a billion transistors each). In this paper, we describe their by-hand process for producing different variations of a computer processor; we'll provide some background on the distributed version control system they were using; we'll describe the architectural changes implemented in BitKeeper for supporting product line work flows; we'll describe some of the changes we did to increase performance and provide some benchmark results comparing BitKeeper to Git, and we'll describe the work flow resulting from using the new architecture to replace their by-hand process. In the final section we'll discuss the current limitations of the existing tool, and describe how we plan on evolving it to overcome those limitations.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129043710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper describes a demonstration of pure::variants, a commercial tool for variant and variability management for product lines. The demonstration shows how flexible product line (PL) architectures can be built, tested and maintained by using the modeling and integration capabilities provided by pure::variants [2].
{"title":"Using pure::variants across the product line lifecycle","authors":"Danilo Beuche","doi":"10.1145/2791060.2791114","DOIUrl":"https://doi.org/10.1145/2791060.2791114","url":null,"abstract":"The paper describes a demonstration of pure::variants, a commercial tool for variant and variability management for product lines. The demonstration shows how flexible product line (PL) architectures can be built, tested and maintained by using the modeling and integration capabilities provided by pure::variants [2].","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"129 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123083167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Engineering a Collective Adaptive System (CAS) requires the support of a framework for quantitative modeling and analysis of the system. In order to jointly address variability and quantitative analysis, we apply the Product Lines paradigm, considered at the level of system engineering, to a case study of the European project QUANTICOL, by first defining a reference feature model and then adding feature attributes and global quantitative constraints, in the form of a Clafer attributed feature model. ClaferMOOVisualizer is subsequently used for quantitative analyses and multi-objective optimization of the resulting attributed feature model.
{"title":"Applying the product lines paradigm to the quantitative analysis of collective adaptive systems","authors":"M. T. Beek, A. Fantechi, S. Gnesi","doi":"10.1145/2791060.2791100","DOIUrl":"https://doi.org/10.1145/2791060.2791100","url":null,"abstract":"Engineering a Collective Adaptive System (CAS) requires the support of a framework for quantitative modeling and analysis of the system. In order to jointly address variability and quantitative analysis, we apply the Product Lines paradigm, considered at the level of system engineering, to a case study of the European project QUANTICOL, by first defining a reference feature model and then adding feature attributes and global quantitative constraints, in the form of a Clafer attributed feature model. ClaferMOOVisualizer is subsequently used for quantitative analyses and multi-objective optimization of the resulting attributed feature model.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128407599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Product lines that use automated tools to configure shared assets (e.g., software or requirements or test cases or user documentation) based on product descriptions have long been known to bring about substantial development cost avoidance when compared to clone-and-own or product-specific development techniques. Now, however, it can be shown that the cost avoidance for configuring multiple shared assets is superlinear -- that is, the overall cost avoidance exceeds the sum of the that brought about by working with each of the shared assets in isolation. That is, a product line that configures (for example) requirements and code will avoid more cost than the sum of code-based plus requirements-based cost avoidance. In addition, we also observe a superlinear effect in terms of the number of products in the portfolio as well. This paper explores why these effects occur, and presents analytical and empirical evidence for their existence from one of the largest and most successful product lines in the literature, the AEGIS Weapon System. The result may lead to new insight into the economics of product line engineering in the systems engineering realm.
{"title":"The more you do, the more you save: the superlinear cost avoidance effect of systems product line engineering","authors":"Susan P. Gregg, Rick Scharadin, P. Clements","doi":"10.1145/2791060.2791065","DOIUrl":"https://doi.org/10.1145/2791060.2791065","url":null,"abstract":"Product lines that use automated tools to configure shared assets (e.g., software or requirements or test cases or user documentation) based on product descriptions have long been known to bring about substantial development cost avoidance when compared to clone-and-own or product-specific development techniques. Now, however, it can be shown that the cost avoidance for configuring multiple shared assets is superlinear -- that is, the overall cost avoidance exceeds the sum of the that brought about by working with each of the shared assets in isolation. That is, a product line that configures (for example) requirements and code will avoid more cost than the sum of code-based plus requirements-based cost avoidance. In addition, we also observe a superlinear effect in terms of the number of products in the portfolio as well. This paper explores why these effects occur, and presents analytical and empirical evidence for their existence from one of the largest and most successful product lines in the literature, the AEGIS Weapon System. The result may lead to new insight into the economics of product line engineering in the systems engineering realm.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131663044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Chavarriaga, Carlos Rangel, Carlos Noguera, R. Casallas, V. Jonckers
Electrical Transformers are complex devices that exhibit an enormous variability depending on the intended power transformation, environmental conditions, standards imposed and customer particularities. Incomplete information or inconsistencies in the specifications can lead to re-processes and higher bid times. This paper presents our experience on using multiple feature models to specify custom Electrical Transformer as a Configuration Process. This process facilitates the elicitation of knowledge from multidisciplinary experts using several feature models, one per domain and per standard and defining relationships among them. This separation of domains eases the analysis and validation of the models. To support the process, we have developed some tools to separate, merge and analyze these models. The final feature models are tested configuring and comparing products from existing company catalogs. We consider that the same strategy can be used in other contexts where experts on multiple disciplines participate.
{"title":"Using multiple feature models to specify configuration options for electrical transformers: an experience report","authors":"J. Chavarriaga, Carlos Rangel, Carlos Noguera, R. Casallas, V. Jonckers","doi":"10.1145/2791060.2791091","DOIUrl":"https://doi.org/10.1145/2791060.2791091","url":null,"abstract":"Electrical Transformers are complex devices that exhibit an enormous variability depending on the intended power transformation, environmental conditions, standards imposed and customer particularities. Incomplete information or inconsistencies in the specifications can lead to re-processes and higher bid times. This paper presents our experience on using multiple feature models to specify custom Electrical Transformer as a Configuration Process. This process facilitates the elicitation of knowledge from multidisciplinary experts using several feature models, one per domain and per standard and defining relationships among them. This separation of domains eases the analysis and validation of the models. To support the process, we have developed some tools to separate, merge and analyze these models. The final feature models are tested configuring and comparing products from existing company catalogs. We consider that the same strategy can be used in other contexts where experts on multiple disciplines participate.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131769984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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