R. Lachmann, Sascha Lity, Sabrina Lischke, Simon Beddig, Sandro Schulze, Ina Schaefer
Software product lines have potential to allow for mass customization of products. Unfortunately, the resulting, vast amount of possible product variants with commonalities and differences leads to new challenges in software testing. Ideally, every product variant should be tested, especially in safety-critical systems. However, due to the exponentially increasing number of product variants, testing every product variant is not feasible. Thus, new concepts and techniques are required to provide efficient SPL testing strategies exploiting the commonalities of software artifacts between product variants to reduce redundancy in testing. In this paper, we present an efficient integration testing approach for SPLs based on delta modeling. We focus on test case prioritization. As a result, only the most important test cases for every product variant are tested, reducing the number of executed test cases significantly, as testing can stop at any given point because of resource constraints while ensuring that the most important test cases have been covered. We present the general concept and our evaluation results. The results show a measurable reduction of executed test cases compared to single-software testing approaches.
{"title":"Delta-oriented test case prioritization for integration testing of software product lines","authors":"R. Lachmann, Sascha Lity, Sabrina Lischke, Simon Beddig, Sandro Schulze, Ina Schaefer","doi":"10.1145/2791060.2791073","DOIUrl":"https://doi.org/10.1145/2791060.2791073","url":null,"abstract":"Software product lines have potential to allow for mass customization of products. Unfortunately, the resulting, vast amount of possible product variants with commonalities and differences leads to new challenges in software testing. Ideally, every product variant should be tested, especially in safety-critical systems. However, due to the exponentially increasing number of product variants, testing every product variant is not feasible. Thus, new concepts and techniques are required to provide efficient SPL testing strategies exploiting the commonalities of software artifacts between product variants to reduce redundancy in testing. In this paper, we present an efficient integration testing approach for SPLs based on delta modeling. We focus on test case prioritization. As a result, only the most important test cases for every product variant are tested, reducing the number of executed test cases significantly, as testing can stop at any given point because of resource constraints while ensuring that the most important test cases have been covered. We present the general concept and our evaluation results. The results show a measurable reduction of executed test cases compared to single-software testing approaches.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"46 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":"125137461","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}
T. Berger, Daniela Rabiser, J. Rubin, P. Grünbacher, Adeline Silva, Martin Becker, M. Chechik, K. Czarnecki
The notion of features is commonly used to describe the functional and non-functional characteristics of a system. In software product line engineering, features often become the prime entities of software reuse and are used to distinguish the individual products of a product line. Properly decomposing a product line into features, and correctly using features in all engineering phases, is core to the immediate and long-term success of such a system. Yet, although more than ten different definitions of the term feature exist, it is still a very abstract concept. Definitions lack concrete guidelines on how to use the notion of features in practice. To address this gap, we present a qualitative empirical study on actual feature usage in industry. Our study covers three large companies and an in-depth, contextualized analysis of 23 features, perceived by the interviewees as typical, atypical (outlier), good, or bad representatives of features. Using structured interviews, we investigate the rationales that lead to a feature's perception, and identify and analyze core characteristics (facets) of these features. Among others, we find that good features precisely describe customer-relevant functionality, while bad features primarily arise from rashly executed processes. Outlier features, serving unusual purposes, are necessary, but do not require the full engineering process of typical features.
{"title":"What is a feature?: a qualitative study of features in industrial software product lines","authors":"T. Berger, Daniela Rabiser, J. Rubin, P. Grünbacher, Adeline Silva, Martin Becker, M. Chechik, K. Czarnecki","doi":"10.1145/2791060.2791108","DOIUrl":"https://doi.org/10.1145/2791060.2791108","url":null,"abstract":"The notion of features is commonly used to describe the functional and non-functional characteristics of a system. In software product line engineering, features often become the prime entities of software reuse and are used to distinguish the individual products of a product line. Properly decomposing a product line into features, and correctly using features in all engineering phases, is core to the immediate and long-term success of such a system. Yet, although more than ten different definitions of the term feature exist, it is still a very abstract concept. Definitions lack concrete guidelines on how to use the notion of features in practice. To address this gap, we present a qualitative empirical study on actual feature usage in industry. Our study covers three large companies and an in-depth, contextualized analysis of 23 features, perceived by the interviewees as typical, atypical (outlier), good, or bad representatives of features. Using structured interviews, we investigate the rationales that lead to a feature's perception, and identify and analyze core characteristics (facets) of these features. Among others, we find that good features precisely describe customer-relevant functionality, while bad features primarily arise from rashly executed processes. Outlier features, serving unusual purposes, are necessary, but do not require the full engineering process of typical features.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"73 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":"116616057","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. Muñoz-Fernández, Gabriel Tamura, I. Raicu, R. Mazo, C. Salinesi
Model simulation has demonstrated its usefulness in evaluation and decision-making for improving preliminary versions of artefacts before production. Particularly, one of the main goals of simulation is to verify model properties based on data collected from its execution. In this paper, we present the simulation capabilities of our REFAS framework for specifying requirements models for dynamic software products lines and self-adaptive systems. The simulation is controlled by a feedback loop and a reasoning engine that operates on the functional and non-functional requirements. The paper contribution is threefold. First, REFAS allows developers to evaluate and improve requirements models through their simulation capabilities. Second, REFAS provides rich feedback in its interactive simulations for the human modeller to make informed decisions to improve her model. Third, REFAS automates the generation of simulation scenarios required to verify the model adequacy and correctness. We evaluate our contribution by comparing the application of REFAS to a case study used in other approaches.
{"title":"REFAS: a PLE approach for simulation of self-adaptive systems requirements","authors":"J. Muñoz-Fernández, Gabriel Tamura, I. Raicu, R. Mazo, C. Salinesi","doi":"10.1145/2791060.2791102","DOIUrl":"https://doi.org/10.1145/2791060.2791102","url":null,"abstract":"Model simulation has demonstrated its usefulness in evaluation and decision-making for improving preliminary versions of artefacts before production. Particularly, one of the main goals of simulation is to verify model properties based on data collected from its execution. In this paper, we present the simulation capabilities of our REFAS framework for specifying requirements models for dynamic software products lines and self-adaptive systems. The simulation is controlled by a feedback loop and a reasoning engine that operates on the functional and non-functional requirements. The paper contribution is threefold. First, REFAS allows developers to evaluate and improve requirements models through their simulation capabilities. Second, REFAS provides rich feedback in its interactive simulations for the human modeller to make informed decisions to improve her model. Third, REFAS automates the generation of simulation scenarios required to verify the model adequacy and correctness. We evaluate our contribution by comparing the application of REFAS to a case study used in other approaches.","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":"129048223","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}
Feature-oriented software development still register few cases of adoption in industry. At least to some extent, such lower adotion might derive from the lack of evidence of its gains in the overall software project costs. This Ph.D thesis aims to improve the state-of-the-art by adding evidence to the body of knowledge on the adoption of Software Product Line (SPL) hybrid composition approahces.
{"title":"Understanding hybrid SPL composition impact on the refactoring into SPL","authors":"A. R. Santos","doi":"10.1145/2791060.2796539","DOIUrl":"https://doi.org/10.1145/2791060.2796539","url":null,"abstract":"Feature-oriented software development still register few cases of adoption in industry. At least to some extent, such lower adotion might derive from the lack of evidence of its gains in the overall software project costs. This Ph.D thesis aims to improve the state-of-the-art by adding evidence to the body of knowledge on the adoption of Software Product Line (SPL) hybrid composition approahces.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"162 12","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114106760","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}
Édipo Luis Féderle, T. Ferreira, T. Colanzi, S. Vergilio
The Product Line Architecture (PLA) design is a complex task, influenced by many factors such as feature modularization and PLA extensibility, which are usually evaluated according to different metrics. Hence, the PLA design is an optimization problem and problems like that have been successfully solved in the Search-Based Software Engineering (SBSE) area, by using metaheuristics such as Genetic Algorithm. Considering this fact, this paper introduces a tool named OPLA-Tool, conceived to provide computer support to a search-based approach for PLA design. OPLA-Tool implements all the steps necessary to use multi-objective optimization algorithms, including PLA transformations and visualization through a graphical interface. OPLA-Tool receives as input a PLA at the class diagram level, and produces a set of good alternative diagrams in terms of cohesion, feature modularization and reduction of crosscutting concerns.
{"title":"OPLA-tool: a support tool for search-based product line architecture design","authors":"Édipo Luis Féderle, T. Ferreira, T. Colanzi, S. Vergilio","doi":"10.1145/2791060.2791096","DOIUrl":"https://doi.org/10.1145/2791060.2791096","url":null,"abstract":"The Product Line Architecture (PLA) design is a complex task, influenced by many factors such as feature modularization and PLA extensibility, which are usually evaluated according to different metrics. Hence, the PLA design is an optimization problem and problems like that have been successfully solved in the Search-Based Software Engineering (SBSE) area, by using metaheuristics such as Genetic Algorithm. Considering this fact, this paper introduces a tool named OPLA-Tool, conceived to provide computer support to a search-based approach for PLA design. OPLA-Tool implements all the steps necessary to use multi-objective optimization algorithms, including PLA transformations and visualization through a graphical interface. OPLA-Tool receives as input a PLA at the class diagram level, and produces a set of good alternative diagrams in terms of cohesion, feature modularization and reduction of crosscutting concerns.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"24 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":"132904856","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}
Lothar Hotz, Yibo Wang, Matthias Riebisch, Olaf Götz, Josef Lackhove
Automation systems in industry are often software-intensive systems consisting of software and hardware components. During their development several engineers of different disciplines are involved, such as mechanical, electrical and software engineering. Each engineer focuses on specific system aspects to be developed. To enable an efficient development, product lines especially with feature models for variability modeling are promising technologies. In order to reduce the complexity of both feature models and development process, views on feature models can be applied. The use of views for filtering purposes constitutes an established method. However, views also enable further options missing in current approaches, such as evaluations regarding requirements, including non-functional ones. This paper presents an approach for evaluation across multiple views to enable collaborative development for developers who focus on different system aspects. We validate our approach by applying it in an industrial project for the planning of flying saws.
{"title":"Evaluation across multiple views for variable automation systems","authors":"Lothar Hotz, Yibo Wang, Matthias Riebisch, Olaf Götz, Josef Lackhove","doi":"10.1145/2791060.2791082","DOIUrl":"https://doi.org/10.1145/2791060.2791082","url":null,"abstract":"Automation systems in industry are often software-intensive systems consisting of software and hardware components. During their development several engineers of different disciplines are involved, such as mechanical, electrical and software engineering. Each engineer focuses on specific system aspects to be developed. To enable an efficient development, product lines especially with feature models for variability modeling are promising technologies. In order to reduce the complexity of both feature models and development process, views on feature models can be applied. The use of views for filtering purposes constitutes an established method. However, views also enable further options missing in current approaches, such as evaluations regarding requirements, including non-functional ones. This paper presents an approach for evaluation across multiple views to enable collaborative development for developers who focus on different system aspects. We validate our approach by applying it in an industrial project for the planning of flying saws.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"103 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":"116297161","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}
This work studies systematic reuse in the context of self-adaptive software systems. In our work, we realized that managing variability for such platforms is different compared to traditional platforms, primarily due to the run-time variability and system uncertainties. Motivated by the fact that recent trends show that self-adaptation will be used more often in future system generation and that software reuse state-of-practice or research do not provide sufficient support, we have investigated the problems and possibly resolutions in this context. We have analyzed variability for these systems, using a systematic reuse prism, and identified a research gap in variability management. The analysis divides variability handling into four activities: (1) identify variability, (2) constrain variability, (3) implement variability, and (4) manage variability. Based on the findings we envision a reuse framework for the specific domain and present an example framework that addresses some of the identified challenges. We argue that it provides basic support for engineering self-adaptive software systems with systematic reuse. We discuss some important avenues of research for achieving the vision.
{"title":"Harnessing variability in product-lines of self-adaptive software systems","authors":"Nadeem Abbas, J. Andersson","doi":"10.1145/2791060.2791089","DOIUrl":"https://doi.org/10.1145/2791060.2791089","url":null,"abstract":"This work studies systematic reuse in the context of self-adaptive software systems. In our work, we realized that managing variability for such platforms is different compared to traditional platforms, primarily due to the run-time variability and system uncertainties. Motivated by the fact that recent trends show that self-adaptation will be used more often in future system generation and that software reuse state-of-practice or research do not provide sufficient support, we have investigated the problems and possibly resolutions in this context. We have analyzed variability for these systems, using a systematic reuse prism, and identified a research gap in variability management. The analysis divides variability handling into four activities: (1) identify variability, (2) constrain variability, (3) implement variability, and (4) manage variability. Based on the findings we envision a reuse framework for the specific domain and present an example framework that addresses some of the identified challenges. We argue that it provides basic support for engineering self-adaptive software systems with systematic reuse. We discuss some important avenues of research for achieving the vision.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"130 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":"127098068","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}
Dennis Reuling, Johannes Bürdek, Serge Rotärmel, Malte Lochau, U. Kelter
Testing every member of a product line individually is often impracticable due to large number of possible product configurations. Thus, feature models are frequently used to generate samples, i.e., subsets of product configurations under test. Besides the extensively studied combinatorial interaction testing (CIT) approach for coverage-driven sample generation, only few approaches exist so far adopting mutation testing to emulate faults in feature models to be detected by a sample. In this paper, we present a mutation-based sampling framework for fault-based product-line testing. We define a comprehensive catalog of atomic mutation operators on the graphical representation of feature models. This way, we are able (1) to also define complex mutation operators emulating more subtle faults, and (2) to classify operators semantically, e.g., to avoid redundant and equivalent mutants. We further introduce similarity-based mutant selection and higher order mutation strategies to reduce testing efforts. Our implementation is based on the graph transformation engine Henshin and is evaluated concerning effectiveness/efficiency trade-offs.
{"title":"Fault-based product-line testing: effective sample generation based on feature-diagram mutation","authors":"Dennis Reuling, Johannes Bürdek, Serge Rotärmel, Malte Lochau, U. Kelter","doi":"10.1145/2791060.2791074","DOIUrl":"https://doi.org/10.1145/2791060.2791074","url":null,"abstract":"Testing every member of a product line individually is often impracticable due to large number of possible product configurations. Thus, feature models are frequently used to generate samples, i.e., subsets of product configurations under test. Besides the extensively studied combinatorial interaction testing (CIT) approach for coverage-driven sample generation, only few approaches exist so far adopting mutation testing to emulate faults in feature models to be detected by a sample. In this paper, we present a mutation-based sampling framework for fault-based product-line testing. We define a comprehensive catalog of atomic mutation operators on the graphical representation of feature models. This way, we are able (1) to also define complex mutation operators emulating more subtle faults, and (2) to classify operators semantically, e.g., to avoid redundant and equivalent mutants. We further introduce similarity-based mutant selection and higher order mutation strategies to reduce testing efforts. Our implementation is based on the graph transformation engine Henshin and is evaluated concerning effectiveness/efficiency trade-offs.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"100 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":"126964633","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}
As the complexity of avionic systems increases, the aerospace industry is turning to product-line engineering and model-based development to better manage complexity and reduce cost. This paper describes a method and a pattern catalog for modeling avionics product lines in SysML, a standard systems modeling language. The method is designed to satisfy aerospace systems and software development standards, and the patterns provide guidance for expressing variability in SysML. The paper also reports on the experience in applying the method and the patterns to model families of propeller controllers and fuel controllers for turbo engines.
{"title":"Modeling aerospace systems product lines in SysML","authors":"Jesús Padilla, K. Czarnecki","doi":"10.1145/2791060.2791104","DOIUrl":"https://doi.org/10.1145/2791060.2791104","url":null,"abstract":"As the complexity of avionic systems increases, the aerospace industry is turning to product-line engineering and model-based development to better manage complexity and reduce cost. This paper describes a method and a pattern catalog for modeling avionics product lines in SysML, a standard systems modeling language. The method is designed to satisfy aerospace systems and software development standards, and the patterns provide guidance for expressing variability in SysML. The paper also reports on the experience in applying the method and the patterns to model families of propeller controllers and fuel controllers for turbo engines.","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":"121810395","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}
Clément Quinton, Rick Rabiser, Michael Vierhauser, P. Grünbacher, L. Baresi
In many domains systems need to run continuously and cannot be shut down for reconfiguration or maintenance tasks. Cyber-physical or cloud-based systems, for instance, thus often provide means to support their adaptation at runtime. The required flexibility and adaptability of systems suggests the application of Software Product Line (spl) principles to manage their variability and to support their reconfiguration. Specifically, Dynamic Software Product Lines (dspl) have been proposed to support the management and binding of variability at runtime. While spl evolution has been widely studied, it has so far not been investigated in detail in a dspl context. Variability models that are used in a dspl have to co-evolve and be kept consistent with the systems they represent to support reconfiguration even after changes to the systems at runtime. In this short paper we present a classification of the required operations for jointly evolving problem and solution space in a dspl. We analyze the impact of such operations on the consistency of a dspl and propose an approach to deal with the described issues. We describe a runtime monitoring system used in the domain of industrial automation software as an example of a dspl evolving at runtime to motivate and explain our work.
{"title":"Evolution in dynamic software product lines: challenges and perspectives","authors":"Clément Quinton, Rick Rabiser, Michael Vierhauser, P. Grünbacher, L. Baresi","doi":"10.1145/2791060.2791101","DOIUrl":"https://doi.org/10.1145/2791060.2791101","url":null,"abstract":"In many domains systems need to run continuously and cannot be shut down for reconfiguration or maintenance tasks. Cyber-physical or cloud-based systems, for instance, thus often provide means to support their adaptation at runtime. The required flexibility and adaptability of systems suggests the application of Software Product Line (spl) principles to manage their variability and to support their reconfiguration. Specifically, Dynamic Software Product Lines (dspl) have been proposed to support the management and binding of variability at runtime. While spl evolution has been widely studied, it has so far not been investigated in detail in a dspl context. Variability models that are used in a dspl have to co-evolve and be kept consistent with the systems they represent to support reconfiguration even after changes to the systems at runtime. In this short paper we present a classification of the required operations for jointly evolving problem and solution space in a dspl. We analyze the impact of such operations on the consistency of a dspl and propose an approach to deal with the described issues. We describe a runtime monitoring system used in the domain of industrial automation software as an example of a dspl evolving at runtime to motivate and explain our work.","PeriodicalId":339158,"journal":{"name":"Proceedings of the 19th International Conference on Software Product Line","volume":"54 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":"122897204","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}
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：