Pub Date : 2007-10-22DOI: 10.1109/ICSM.2007.4362624
Bram Adams, H. Tromp, K. Schutter, W. Meuter
The build system forms an indispensable part of any software project. It needs to evolve in parallel with the source code in order to build, test and install the software. Unfortunately, little tool support exists to help maintainers gain insight into the build system, much less to refactor it. In this paper, we therefore present the design and implementation of a re(verse)-engineering framework for build systems named MAKAO. At its heart the framework makes the build's dependency graph available in a tangible way. Aside from visualisation, this enables powerful querying of all build-related data, as well as various filtering techniques to define views on the build architecture. If desired, all this gathered information can be put to use to write aspects for refactoring the build. Afterwards, validation rules can help in assessing failure or success. We applied our implementation on an industrial C system and the Linux 2.6.16.18 kernel, with good results.
{"title":"Design recovery and maintenance of build systems","authors":"Bram Adams, H. Tromp, K. Schutter, W. Meuter","doi":"10.1109/ICSM.2007.4362624","DOIUrl":"https://doi.org/10.1109/ICSM.2007.4362624","url":null,"abstract":"The build system forms an indispensable part of any software project. It needs to evolve in parallel with the source code in order to build, test and install the software. Unfortunately, little tool support exists to help maintainers gain insight into the build system, much less to refactor it. In this paper, we therefore present the design and implementation of a re(verse)-engineering framework for build systems named MAKAO. At its heart the framework makes the build's dependency graph available in a tangible way. Aside from visualisation, this enables powerful querying of all build-related data, as well as various filtering techniques to define views on the build architecture. If desired, all this gathered information can be put to use to write aspects for refactoring the build. Afterwards, validation rules can help in assessing failure or success. We applied our implementation on an industrial C system and the Linux 2.6.16.18 kernel, with good results.","PeriodicalId":263470,"journal":{"name":"2007 IEEE International Conference on Software Maintenance","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115112637","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}
Pub Date : 2007-10-22DOI: 10.1109/ICSM.2007.4362622
Stéphane Ducasse, Damien Pollet, Mathieu Suen, H. Abdeen, Ilham Alloui
Large object-oriented applications are structured over large number of packages. Packages are important but complex structural entities that may be difficult to understand since they play different development roles (i.e., class containers, code ownership basic structure, architectural elements...). Maintainers of large applications face the problem of understanding how packages are structured in general and how they relate to each others. In this paper, we present a compact visualization, named Package Surface Blueprint, that qualifies the relationships that a package has with its neighbours. A Package Surface Blueprint represents packages around the notion of package surfaces: groups of relationships according to the packages they refer to. We present two specific views one stressing the references made by a package and another showing the inheritance structure of a package. We applied the visualization on two large case studies: ArgoUML and Squeak.
{"title":"Package Surface Blueprints: Visually Supporting the Understanding of Package Relationships","authors":"Stéphane Ducasse, Damien Pollet, Mathieu Suen, H. Abdeen, Ilham Alloui","doi":"10.1109/ICSM.2007.4362622","DOIUrl":"https://doi.org/10.1109/ICSM.2007.4362622","url":null,"abstract":"Large object-oriented applications are structured over large number of packages. Packages are important but complex structural entities that may be difficult to understand since they play different development roles (i.e., class containers, code ownership basic structure, architectural elements...). Maintainers of large applications face the problem of understanding how packages are structured in general and how they relate to each others. In this paper, we present a compact visualization, named Package Surface Blueprint, that qualifies the relationships that a package has with its neighbours. A Package Surface Blueprint represents packages around the notion of package surfaces: groups of relationships according to the packages they refer to. We present two specific views one stressing the references made by a package and another showing the inheritance structure of a package. We applied the visualization on two large case studies: ArgoUML and Squeak.","PeriodicalId":263470,"journal":{"name":"2007 IEEE International Conference on Software Maintenance","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115651124","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}
Pub Date : 2007-10-22DOI: 10.1109/ICSM.2007.4362655
Roberta Coelho, Elder Cirilo, U. Kulesza, Arndt von Staa, A. Rashid, C. Lucena
Automated tests have been widely used as a supporting mechanism during software development and maintenance activities. It improves the confidence on software releases as it seeks to uncover regression bugs, and serves as a live documentation which is very useful when evolving systems. Concerning multi agent systems (MASs), some characteristics such as agent autonomy and asynchronous message-based interaction bring a degree of non-determinism which presents new testing challenges. This paper proposes JAT, a framework for building and running MASs test scenarios, which relies on the use of aspect-oriented techniques to monitor the autonomous agents during tests and control the test input of asynchronous test cases. The tool has been developed on top of JADE, a widely used agent platform implemented in Java. We have used JAT on testing 3 different MASs. Our experience shows that JAT can be used to build test scenarios which can achieve high fault-detection effectiveness.
{"title":"JAT: A Test Automation Framework for Multi-Agent Systems","authors":"Roberta Coelho, Elder Cirilo, U. Kulesza, Arndt von Staa, A. Rashid, C. Lucena","doi":"10.1109/ICSM.2007.4362655","DOIUrl":"https://doi.org/10.1109/ICSM.2007.4362655","url":null,"abstract":"Automated tests have been widely used as a supporting mechanism during software development and maintenance activities. It improves the confidence on software releases as it seeks to uncover regression bugs, and serves as a live documentation which is very useful when evolving systems. Concerning multi agent systems (MASs), some characteristics such as agent autonomy and asynchronous message-based interaction bring a degree of non-determinism which presents new testing challenges. This paper proposes JAT, a framework for building and running MASs test scenarios, which relies on the use of aspect-oriented techniques to monitor the autonomous agents during tests and control the test input of asynchronous test cases. The tool has been developed on top of JADE, a widely used agent platform implemented in Java. We have used JAT on testing 3 different MASs. Our experience shows that JAT can be used to build test scenarios which can achieve high fault-detection effectiveness.","PeriodicalId":263470,"journal":{"name":"2007 IEEE International Conference on Software Maintenance","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117122670","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}
Pub Date : 2007-10-22DOI: 10.1109/ICSM.2007.4362641
Abram Hindle, Michael W. Godfrey, R. Holt
Studying the release-time activities of a software project - that is, activities that occur around the time of a major or minor release - can provide insights into both the development processes used and the nature of the system itself. Although tools rarely record detailed logs of developer behavior, we can infer release-time activities from available data, such as logs from revision control systems, bug tracking systems, etc. In this paper, we discuss the results of a case study in mining patterns of release-time behavior from the revision control systems of four open source database systems. We partitioned the development artifacts into four classes - source code, tests, build files, and documentation - to be able to characterize the behavioral patterns more precisely. We found, for example, that there were consistent activity patterns around release time within each of the individual projects; we also found that these patterns did not persist across systems, leading us to hypothesize that the four projects follow different but consistent development patterns of activity around releases.
{"title":"Release Pattern Discovery: A Case Study of Database Systems","authors":"Abram Hindle, Michael W. Godfrey, R. Holt","doi":"10.1109/ICSM.2007.4362641","DOIUrl":"https://doi.org/10.1109/ICSM.2007.4362641","url":null,"abstract":"Studying the release-time activities of a software project - that is, activities that occur around the time of a major or minor release - can provide insights into both the development processes used and the nature of the system itself. Although tools rarely record detailed logs of developer behavior, we can infer release-time activities from available data, such as logs from revision control systems, bug tracking systems, etc. In this paper, we discuss the results of a case study in mining patterns of release-time behavior from the revision control systems of four open source database systems. We partitioned the development artifacts into four classes - source code, tests, build files, and documentation - to be able to characterize the behavioral patterns more precisely. We found, for example, that there were consistent activity patterns around release time within each of the individual projects; we also found that these patterns did not persist across systems, leading us to hypothesize that the four projects follow different but consistent development patterns of activity around releases.","PeriodicalId":263470,"journal":{"name":"2007 IEEE International Conference on Software Maintenance","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116292863","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}
Pub Date : 2007-10-22DOI: 10.1109/ICSM.2007.4362650
Xinyi Dong, Michael W. Godfrey
Uncovering, modelling, and understanding architectural level dependencies of software systems is a key task for software maintainers. However, current dependency analysis techniques for object-oriented software are targeted at the class or method level; this is because most dependencies - such as instantiates, references, and calls - must be interpreted in the context of one or more class hierarchies. In this paper, we propose an approach, called the high-level object dependency graph (HODG), that captures all possible usage dependencies among coarse-grained entities. Based on the new model, we further propose a set of dependency analysis methods. Finally, we present an exploratory case study using HODGs - supported by an automated analysis tool - of the Apache Ant build system; we show how HODG analysis can help maintainers capture external properties of coarse-grained entities, and better understand the nature of their interdependencies.
{"title":"System-level Usage Dependency Analysis of Object-Oriented Systems","authors":"Xinyi Dong, Michael W. Godfrey","doi":"10.1109/ICSM.2007.4362650","DOIUrl":"https://doi.org/10.1109/ICSM.2007.4362650","url":null,"abstract":"Uncovering, modelling, and understanding architectural level dependencies of software systems is a key task for software maintainers. However, current dependency analysis techniques for object-oriented software are targeted at the class or method level; this is because most dependencies - such as instantiates, references, and calls - must be interpreted in the context of one or more class hierarchies. In this paper, we propose an approach, called the high-level object dependency graph (HODG), that captures all possible usage dependencies among coarse-grained entities. Based on the new model, we further propose a set of dependency analysis methods. Finally, we present an exploratory case study using HODGs - supported by an automated analysis tool - of the Apache Ant build system; we show how HODG analysis can help maintainers capture external properties of coarse-grained entities, and better understand the nature of their interdependencies.","PeriodicalId":263470,"journal":{"name":"2007 IEEE International Conference on Software Maintenance","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127045222","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}
Pub Date : 2007-10-22DOI: 10.1109/ICSM.2007.4362629
Pavan Kumar Chittimalli, M. J. Harrold
This paper presents a technique that leverages an existing regression test-selection algorithm to compute accurate, updated coverage data on a version of the software, Pi+1, without rerunning any test cases that do not execute the changes from the previous version of the software, Pi, to Pi+1-Users of our technique can avoid the expense of rerunning the entire test suite on Pi+1 or the inaccuracy produced by previous approaches that estimate coverage data for Pi+1 or reuse outdated coverage data from Pi. This paper also presents a tool, RECOVER, that implements our technique, along with a set of empirical studies. The studies show the inaccuracies that can exist when an application-regression-test selection-uses estimated and outdated coverage data. The studies also show that the overhead incurred by our technique is negligible.
{"title":"Re-computing Coverage Information to Assist Regression Testing","authors":"Pavan Kumar Chittimalli, M. J. Harrold","doi":"10.1109/ICSM.2007.4362629","DOIUrl":"https://doi.org/10.1109/ICSM.2007.4362629","url":null,"abstract":"This paper presents a technique that leverages an existing regression test-selection algorithm to compute accurate, updated coverage data on a version of the software, Pi+1, without rerunning any test cases that do not execute the changes from the previous version of the software, Pi, to Pi+1-Users of our technique can avoid the expense of rerunning the entire test suite on Pi+1 or the inaccuracy produced by previous approaches that estimate coverage data for Pi+1 or reuse outdated coverage data from Pi. This paper also presents a tool, RECOVER, that implements our technique, along with a set of empirical studies. The studies show the inaccuracies that can exist when an application-regression-test selection-uses estimated and outdated coverage data. The studies also show that the overhead incurred by our technique is negligible.","PeriodicalId":263470,"journal":{"name":"2007 IEEE International Conference on Software Maintenance","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132472830","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}
Pub Date : 2007-10-22DOI: 10.1109/ICSM.2007.4362618
Neil Walkinshaw, M. Roper, M. Wood
Identifying and isolating the source code associated with a particular feature is a problem that frequently arises in many maintenance tasks. The delocalised nature of object-oriented systems, where the code associated with a feature is distributed across many interrelated objects, makes this problem particularly challenging. This paper presents an approach that combines landmark' methods that have a key role in the execution of a particular feature with slicing to create a call graph of related code. The size of this call graph is constrained by the identification of 'barrier' methods which exclude parts of the graph that are not of interest. The approach is supported by a tool, and the evaluation on three open-source systems yields encouraging results and demonstrates the practical applicability of the technique.
{"title":"Feature Location and Extraction using Landmarks and Barriers","authors":"Neil Walkinshaw, M. Roper, M. Wood","doi":"10.1109/ICSM.2007.4362618","DOIUrl":"https://doi.org/10.1109/ICSM.2007.4362618","url":null,"abstract":"Identifying and isolating the source code associated with a particular feature is a problem that frequently arises in many maintenance tasks. The delocalised nature of object-oriented systems, where the code associated with a feature is distributed across many interrelated objects, makes this problem particularly challenging. This paper presents an approach that combines landmark' methods that have a key role in the execution of a particular feature with slicing to create a call graph of related code. The size of this call graph is constrained by the identification of 'barrier' methods which exclude parts of the graph that are not of interest. The approach is supported by a tool, and the evaluation on three open-source systems yields encouraging results and demonstrates the practical applicability of the technique.","PeriodicalId":263470,"journal":{"name":"2007 IEEE International Conference on Software Maintenance","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133229568","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}
Pub Date : 2007-10-22DOI: 10.1109/ICSM.2007.4362638
Xiao Qu, Myra B. Cohen, Katherine M. Woolf
Regression testing is an expensive part of the software maintenance process. Effective regression testing techniques select and order (or prioritize) test cases between successive releases of a program. However, selection and prioritization are dependent on the quality of the initial test suite. An effective and cost efficient test generation technique is combinatorial interaction testing, CIT, which systematically samples all t-way combinations of input parameters. Research on CIT, to date, has focused on single version software systems. There has been little work that empirically assesses the use of CIT test generation as the basis for selection or prioritization. In this paper we examine the effectiveness of CIT across multiple versions of two software subjects. Our results show that CIT performs well in finding seeded faults when compared with an exhaustive test set. We examine several CIT prioritization techniques and compare them with a re-generation/prioritization technique. We find that prioritized and re-generated/prioritized CIT test suites may find faults earlier than unordered CIT test suites, although the re-generated/prioritized test suites sometimes exhibit decreased fault detection.
{"title":"Combinatorial Interaction Regression Testing: A Study of Test Case Generation and Prioritization","authors":"Xiao Qu, Myra B. Cohen, Katherine M. Woolf","doi":"10.1109/ICSM.2007.4362638","DOIUrl":"https://doi.org/10.1109/ICSM.2007.4362638","url":null,"abstract":"Regression testing is an expensive part of the software maintenance process. Effective regression testing techniques select and order (or prioritize) test cases between successive releases of a program. However, selection and prioritization are dependent on the quality of the initial test suite. An effective and cost efficient test generation technique is combinatorial interaction testing, CIT, which systematically samples all t-way combinations of input parameters. Research on CIT, to date, has focused on single version software systems. There has been little work that empirically assesses the use of CIT test generation as the basis for selection or prioritization. In this paper we examine the effectiveness of CIT across multiple versions of two software subjects. Our results show that CIT performs well in finding seeded faults when compared with an exhaustive test set. We examine several CIT prioritization techniques and compare them with a re-generation/prioritization technique. We find that prioritized and re-generated/prioritized CIT test suites may find faults earlier than unordered CIT test suites, although the re-generated/prioritized test suites sometimes exhibit decreased fault detection.","PeriodicalId":263470,"journal":{"name":"2007 IEEE International Conference on Software Maintenance","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129342305","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}
Pub Date : 2007-10-22DOI: 10.1109/ICSM.2007.4362648
Xiaoyu Zheng, Mei-Hwa Chen
Large-scale multi-tier web applications are inherently dynamic, complex, heterogeneous and constantly evolving. Maintaining such applications is important yet inevitably expensive. First, the size of the test suite of an evolving system will be continuously growing. Second, to ensure that the changes will not affect the quality of the systems, regression testing is frequently performed. To effectively and efficiently maintain web applications after each change, obsolete test cases must be removed and regression testing should selectively re-test. To this end there is a need for an inter-tier change impact analysis, which requires a coherent model rendering inter-tier dependence information. We present a technique that makes use of an integrated inter-connection dependence model to analyze cross-tier change impacts. These are then used to select affected test cases for regression testing and to identify repairable test cases for reuse, or to discard obsolete non-repairable test cases. Our empirical study shows that with this technique, the maintenance cost of the target system can be significantly reduced.
{"title":"Maintaining Multi-Tier Web Applications","authors":"Xiaoyu Zheng, Mei-Hwa Chen","doi":"10.1109/ICSM.2007.4362648","DOIUrl":"https://doi.org/10.1109/ICSM.2007.4362648","url":null,"abstract":"Large-scale multi-tier web applications are inherently dynamic, complex, heterogeneous and constantly evolving. Maintaining such applications is important yet inevitably expensive. First, the size of the test suite of an evolving system will be continuously growing. Second, to ensure that the changes will not affect the quality of the systems, regression testing is frequently performed. To effectively and efficiently maintain web applications after each change, obsolete test cases must be removed and regression testing should selectively re-test. To this end there is a need for an inter-tier change impact analysis, which requires a coherent model rendering inter-tier dependence information. We present a technique that makes use of an integrated inter-connection dependence model to analyze cross-tier change impacts. These are then used to select affected test cases for regression testing and to identify repairable test cases for reuse, or to discard obsolete non-repairable test cases. Our empirical study shows that with this technique, the maintenance cost of the target system can be significantly reduced.","PeriodicalId":263470,"journal":{"name":"2007 IEEE International Conference on Software Maintenance","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131553424","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}
Pub Date : 2007-10-22DOI: 10.1109/ICSM.2007.4362617
D. Brand, M. Buss, V. Sreedhar
An important part of software maintenance is fixing software errors and bugs. Static analysis based tools can tremendously help and ease software maintenance. In order to gain user acceptance, a static analysis tool for detecting bugs has to minimize the incidence of false alarms. A common cause of false alarms is the uncertainty over which inputs into a program are considered legal. In this paper we introduce evidence-based analysis to address this problem. Evidence-based analysis allows one to infer legal preconditions over inputs, without having users to explicitly specify those preconditions. We have found that the approach drastically improves the usability of such static analysis tools. In this paper we report our experience with the analysis in an industrial deployment.
{"title":"Evidence-Based Analysis and Inferring Preconditions for Bug Detection","authors":"D. Brand, M. Buss, V. Sreedhar","doi":"10.1109/ICSM.2007.4362617","DOIUrl":"https://doi.org/10.1109/ICSM.2007.4362617","url":null,"abstract":"An important part of software maintenance is fixing software errors and bugs. Static analysis based tools can tremendously help and ease software maintenance. In order to gain user acceptance, a static analysis tool for detecting bugs has to minimize the incidence of false alarms. A common cause of false alarms is the uncertainty over which inputs into a program are considered legal. In this paper we introduce evidence-based analysis to address this problem. Evidence-based analysis allows one to infer legal preconditions over inputs, without having users to explicitly specify those preconditions. We have found that the approach drastically improves the usability of such static analysis tools. In this paper we report our experience with the analysis in an industrial deployment.","PeriodicalId":263470,"journal":{"name":"2007 IEEE International Conference on Software Maintenance","volume":"165 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131007452","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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