Data stream processing can be applied in scenarios where high throughput and real-time response is required. In distributed environments, preprocessing at sensor nodes is beneficial. Processing logic is deployed at sensor nodes and data is processed while streaming through the nodes. However, updating the logic is difficult in such a continuously running environment. Volatile operator states get lost if nodes are restarted for an update. The challenge is to update the operators during the runtime with the preservation of their states. We developed a data stream processing solution which is capable of adapting the logic on-the-fly. States are copied while migrating from the original to new logic. For implementation, we utilized the dynamic component system OSGi. In this paper we present methods for state selection and transfer from the input buffers of the running operators. The state values to be transferred are limited to a minimum quantity. The state transfer methods allow a faster migration compared to other approaches and a guaranteed output, which makes our system real-time compatible.
{"title":"On-the-Fly Adaptation of Data Stream Queries","authors":"Bernhard Wolf, I. Behrens","doi":"10.1109/ISORC.2010.22","DOIUrl":"https://doi.org/10.1109/ISORC.2010.22","url":null,"abstract":"Data stream processing can be applied in scenarios where high throughput and real-time response is required. In distributed environments, preprocessing at sensor nodes is beneficial. Processing logic is deployed at sensor nodes and data is processed while streaming through the nodes. However, updating the logic is difficult in such a continuously running environment. Volatile operator states get lost if nodes are restarted for an update. The challenge is to update the operators during the runtime with the preservation of their states. We developed a data stream processing solution which is capable of adapting the logic on-the-fly. States are copied while migrating from the original to new logic. For implementation, we utilized the dynamic component system OSGi. In this paper we present methods for state selection and transfer from the input buffers of the running operators. The state values to be transferred are limited to a minimum quantity. The state transfer methods allow a faster migration compared to other approaches and a guaranteed output, which makes our system real-time compatible.","PeriodicalId":142767,"journal":{"name":"2010 13th IEEE International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"362 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115946001","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}
Stefan Henkler, Simon Oberthür, H. Giese, Andreas Seibel
The next generation of advanced mechatronic systems is expected to enhance their functionality and improve their performance by context-dependent behavior. Therefore, these systems require to represent information about the complex environment and changing sets of collaboration partners internally. This requirement is in contrast to the usually assumed static structures for embedded systems. In this paper, we present a model-driven approach which overcomes this situation by supporting dynamic data structures while still guaranteeing that valid worst-case execution times can be derived. It supports a flexible resource management which avoids to operate with the prohibitive coarse worst-case boundaries but instead supports to run applications in different profiles which guarantee different resource requirements and put unused resources in a profile at other applications' disposal. By supporting the proper estimation of worst case execution time (WCET) and worst case number of iteration (WCNI) at runtime, we can further support to create new profiles, add or remove them at runtime in order to minimize the over-approximation of the resource consumption resulting from the dynamic data structures required for the outlined class of advanced systems.
{"title":"Model-Driven Runtime Resource Predictions for Advanced Mechatronic Systems with Dynamic Data Structures","authors":"Stefan Henkler, Simon Oberthür, H. Giese, Andreas Seibel","doi":"10.1109/ISORC.2010.17","DOIUrl":"https://doi.org/10.1109/ISORC.2010.17","url":null,"abstract":"The next generation of advanced mechatronic systems is expected to enhance their functionality and improve their performance by context-dependent behavior. Therefore, these systems require to represent information about the complex environment and changing sets of collaboration partners internally. This requirement is in contrast to the usually assumed static structures for embedded systems. In this paper, we present a model-driven approach which overcomes this situation by supporting dynamic data structures while still guaranteeing that valid worst-case execution times can be derived. It supports a flexible resource management which avoids to operate with the prohibitive coarse worst-case boundaries but instead supports to run applications in different profiles which guarantee different resource requirements and put unused resources in a profile at other applications' disposal. By supporting the proper estimation of worst case execution time (WCET) and worst case number of iteration (WCNI) at runtime, we can further support to create new profiles, add or remove them at runtime in order to minimize the over-approximation of the resource consumption resulting from the dynamic data structures required for the outlined class of advanced systems.","PeriodicalId":142767,"journal":{"name":"2010 13th IEEE International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"149 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131807402","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. Loyall, M. Gillen, Aaron M. Paulos, James R. Edmondson, Pooja Varshneya, D. Schmidt, L. Bunch, M. Carvalho, Andrew J. Martignoni
Service-oriented architecture (SOA) middleware has emerged as a powerful and popular distributed computing paradigm due to its high-level abstractions for composing systems and hiding platform-level details. Control of some details hidden by SOA middleware is necessary, however, to provide managed quality of service (QoS) for SOA systems that need predictable performance and behavior. This paper presents a policy-driven approach for managing QoS in SOA systems. We discuss the design of several key QoS services and empirically evaluate their ability to provide QoS under CPU overload and bandwidth-constrained situations.
{"title":"Dynamic Policy-Driven Quality of Service in Service-Oriented Systems","authors":"J. Loyall, M. Gillen, Aaron M. Paulos, James R. Edmondson, Pooja Varshneya, D. Schmidt, L. Bunch, M. Carvalho, Andrew J. Martignoni","doi":"10.1109/ISORC.2010.13","DOIUrl":"https://doi.org/10.1109/ISORC.2010.13","url":null,"abstract":"Service-oriented architecture (SOA) middleware has emerged as a powerful and popular distributed computing paradigm due to its high-level abstractions for composing systems and hiding platform-level details. Control of some details hidden by SOA middleware is necessary, however, to provide managed quality of service (QoS) for SOA systems that need predictable performance and behavior. This paper presents a policy-driven approach for managing QoS in SOA systems. We discuss the design of several key QoS services and empirically evaluate their ability to provide QoS under CPU overload and bandwidth-constrained situations.","PeriodicalId":142767,"journal":{"name":"2010 13th IEEE International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125385757","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 design and implementation of Real-Time Embedded Systems is now heavily relying on Model-Driven Engineering (MDE) as a central place to define and then analyze or implement a system. MDE toolchains are taking a key role as to gather most of functional and not functional properties in a central framework, and then exploit this information. Such toolchain is based on both 1) a modeling notation, and 2) companion tools to transform or analyse models. In this paper, we present a MDE-based process for system optimisation based on an architectural description. We first define a generic evaluation pipeline, define a library of elementary transformations and then shows how to use it through Domain-Specific Language to evaluate and then transform models. We illustrate this process on an AADL case study modeling a Generic Avionics Platform.
{"title":"A MDE-Based Optimisation Process for Real-Time Systems","authors":"Olivier Gilles, J. Hugues","doi":"10.1109/ISORC.2010.38","DOIUrl":"https://doi.org/10.1109/ISORC.2010.38","url":null,"abstract":"The design and implementation of Real-Time Embedded Systems is now heavily relying on Model-Driven Engineering (MDE) as a central place to define and then analyze or implement a system. MDE toolchains are taking a key role as to gather most of functional and not functional properties in a central framework, and then exploit this information. Such toolchain is based on both 1) a modeling notation, and 2) companion tools to transform or analyse models. In this paper, we present a MDE-based process for system optimisation based on an architectural description. We first define a generic evaluation pipeline, define a library of elementary transformations and then shows how to use it through Domain-Specific Language to evaluate and then transform models. We illustrate this process on an AADL case study modeling a Generic Avionics Platform.","PeriodicalId":142767,"journal":{"name":"2010 13th IEEE International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114120066","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}
D. Arney, S. Fischmeister, Insup Lee, Yoshihito Takashima, Mark H. Yim
Modular robots are a powerful concept for robotics. A modular robot consists of many individual modules so it can adjust its configuration to the problem. However, the fact that a modular robot consists of many individual modules makes it a highly distributed, highly concurrent real-time system, which are notoriously hard to program. In this work, we present our programming framework for writing control applications for modular robots. The framework includes a toolset that allows a model-based programing approach for control application of modular robots with code generation and verification. The framework is characterized by the following three features. First, it provides a complex programming model that is based on standard finite state machines extended in syntax and semantics to support communication, variables, and actions. Second, the framework provides compositionality at the hardware and at the software level and allows building the modular robot and its control application from small building blocks. And third, the framework supports formal verification of the control application to aid the gait and task developer in identifying problems and bugs before the deployment and testing on the physical robot.
{"title":"Model-Based Programming of Modular Robots","authors":"D. Arney, S. Fischmeister, Insup Lee, Yoshihito Takashima, Mark H. Yim","doi":"10.1109/ISORC.2010.16","DOIUrl":"https://doi.org/10.1109/ISORC.2010.16","url":null,"abstract":"Modular robots are a powerful concept for robotics. A modular robot consists of many individual modules so it can adjust its configuration to the problem. However, the fact that a modular robot consists of many individual modules makes it a highly distributed, highly concurrent real-time system, which are notoriously hard to program. In this work, we present our programming framework for writing control applications for modular robots. The framework includes a toolset that allows a model-based programing approach for control application of modular robots with code generation and verification. The framework is characterized by the following three features. First, it provides a complex programming model that is based on standard finite state machines extended in syntax and semantics to support communication, variables, and actions. Second, the framework provides compositionality at the hardware and at the software level and allows building the modular robot and its control application from small building blocks. And third, the framework supports formal verification of the control application to aid the gait and task developer in identifying problems and bugs before the deployment and testing on the physical robot.","PeriodicalId":142767,"journal":{"name":"2010 13th IEEE International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127646594","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}
Publish/subscribe middleware is being increasingly used to devise large-scale critical systems. Although several reliable publish/subscribe solutions have been proposed, none of them properly address the problem of assuring message dissemination even if network omissions happen without breaking any temporal constraints. In order to fill this gap, we have investigated how to guarantee a resilient and timely event dissemination despite of message losses. The contribution of this paper is on proposing a FEC approach, where encoding functionality is placed at the root and on a subset of interior nodes in the multicast tree, combined to a gossiping algorithm. Simulation-based experiments demonstrate that the proposed approach allows all the interested subscribers to receive all the published messages and the adopted resiliency mean does not affect the timeliness of the multicast protocol.
{"title":"Reliable Event Dissemination over Wide-Area Networks without Severe Performance Fluctuations","authors":"C. Esposito, Domenico Cotroneo, S. Russo","doi":"10.1109/ISORC.2010.14","DOIUrl":"https://doi.org/10.1109/ISORC.2010.14","url":null,"abstract":"Publish/subscribe middleware is being increasingly used to devise large-scale critical systems. Although several reliable publish/subscribe solutions have been proposed, none of them properly address the problem of assuring message dissemination even if network omissions happen without breaking any temporal constraints. In order to fill this gap, we have investigated how to guarantee a resilient and timely event dissemination despite of message losses. The contribution of this paper is on proposing a FEC approach, where encoding functionality is placed at the root and on a subset of interior nodes in the multicast tree, combined to a gossiping algorithm. Simulation-based experiments demonstrate that the proposed approach allows all the interested subscribers to receive all the published messages and the adopted resiliency mean does not affect the timeliness of the multicast protocol.","PeriodicalId":142767,"journal":{"name":"2010 13th IEEE International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130441054","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}
High–integrity systems are deployed in order to realize safety–critical applications. To meet the rigorous requirements in this domain, these systems require a sophisticated approach to design, verfication, and certification. Not only safety consideration shave an impact on a product’s overall dependability, but also security has to be taken into account. In this paper we analyze the Time–Triggered System–on–Chip (TTSoC) architecture, which is a novel architecture for Multi–Processor System–on–Chip (MPSoC) devices, regarding its security properties. We discuss essential compliance criteria to the Multiple Independent Layers of Security (MILS) architecture, which is a industry–ready architecture for embedded high–integrity systems. We found that both architectures share intrinsic properties and we are able to show that the TTSoC architecture implements the core requirements of a MILS Separation Kernel and thus realizes its elementary security policies by design.
部署高完整性系统是为了实现安全关键应用。为了满足这个领域的严格要求,这些系统需要一种复杂的方法来设计、验证和认证。不仅安全考虑对产品的整体可靠性有影响,而且安全性也必须考虑在内。本文分析了时间触发片上系统(TTSoC)架构,这是一种多处理器片上系统(MPSoC)器件的新架构,它的安全性能。我们讨论了多独立安全层(Multiple Independent Layers of Security, MILS)体系结构的基本遵从性标准,这是一种适用于嵌入式高完整性系统的行业就绪体系结构。我们发现这两种体系结构共享内在属性,并且我们能够证明TTSoC体系结构实现了MILS分离内核的核心需求,从而通过设计实现了其基本安全策略。
{"title":"A System-on-a-Chip Platform for Mixed-Criticality Applications","authors":"Armin Wasicek, C. E. Salloum, H. Kopetz","doi":"10.1109/ISORC.2010.43","DOIUrl":"https://doi.org/10.1109/ISORC.2010.43","url":null,"abstract":"High–integrity systems are deployed in order to realize safety–critical applications. To meet the rigorous requirements in this domain, these systems require a sophisticated approach to design, verfication, and certification. Not only safety consideration shave an impact on a product’s overall dependability, but also security has to be taken into account. In this paper we analyze the Time–Triggered System–on–Chip (TTSoC) architecture, which is a novel architecture for Multi–Processor System–on–Chip (MPSoC) devices, regarding its security properties. We discuss essential compliance criteria to the Multiple Independent Layers of Security (MILS) architecture, which is a industry–ready architecture for embedded high–integrity systems. We found that both architectures share intrinsic properties and we are able to show that the TTSoC architecture implements the core requirements of a MILS Separation Kernel and thus realizes its elementary security policies by design.","PeriodicalId":142767,"journal":{"name":"2010 13th IEEE International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131235923","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}
Formal verification plays an important role in demonstrating the quality of safety-critical systems such as nuclear power plants. We have used the VIS verification system to determine behavioral equivalence between two successive revisions in developing the KNICS RPS (Reactor Protection System) in Korea. The VIS accepts a high-level programming language Verilog as input, and its verification results contain valuable information about one reason of the failure. However the VIS offers no graphical interface, and partially displays relevant information necessary to understand the full verification scenario accurately. Many nuclear engineers and verification experts found the information insufficient, and it makes hard to the wide use of the VIS verification system in industry. This paper proposes the VIS Analyzer, a visual assistant for VIS verification and analysis, which can help nuclear engineers take full benefits of VIS without being overwhelmed by incomplete and low-level details. The VIS Analyzer automates the VIS verification processes such as equivalence checking and model checking, and displays the verification results in visual formats. We used a recent case study introduced in to demonstrate its effectiveness and usefulness.
{"title":"VIS Analyzer: A Visual Assistant for VIS Verification and Analysis","authors":"S. Jeong, Junbeom Yoo, S. Cha","doi":"10.1109/ISORC.2010.41","DOIUrl":"https://doi.org/10.1109/ISORC.2010.41","url":null,"abstract":"Formal verification plays an important role in demonstrating the quality of safety-critical systems such as nuclear power plants. We have used the VIS verification system to determine behavioral equivalence between two successive revisions in developing the KNICS RPS (Reactor Protection System) in Korea. The VIS accepts a high-level programming language Verilog as input, and its verification results contain valuable information about one reason of the failure. However the VIS offers no graphical interface, and partially displays relevant information necessary to understand the full verification scenario accurately. Many nuclear engineers and verification experts found the information insufficient, and it makes hard to the wide use of the VIS verification system in industry. This paper proposes the VIS Analyzer, a visual assistant for VIS verification and analysis, which can help nuclear engineers take full benefits of VIS without being overwhelmed by incomplete and low-level details. The VIS Analyzer automates the VIS verification processes such as equivalence checking and model checking, and displays the verification results in visual formats. We used a recent case study introduced in to demonstrate its effectiveness and usefulness.","PeriodicalId":142767,"journal":{"name":"2010 13th IEEE International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114541509","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}
Organic Computing is a new and promising research area. Inspired by nature, organic computing research wants to learn and adopt from techniques and properties of nature. The goal is to acquire the so called Self-X properties like self-organization and self-healing. Taking the hormone system of mammals as a role model, the artificial hormone system(AHS) was designed to map tasks on processing elements using artificial hormones. In previous publications we presented the idea of an organic middleware and first theoretical results. As we want to run this middleware in an embedded scenario we will now present an implementation of the AHS written in pure ANSI C and show first real-world scenarios and results of test series.
{"title":"Implementing and Evaluating the AHS Organic Middleware - A First Approach","authors":"Alexander von Renteln, U. Brinkschulte","doi":"10.1109/ISORC.2010.26","DOIUrl":"https://doi.org/10.1109/ISORC.2010.26","url":null,"abstract":"Organic Computing is a new and promising research area. Inspired by nature, organic computing research wants to learn and adopt from techniques and properties of nature. The goal is to acquire the so called Self-X properties like self-organization and self-healing. Taking the hormone system of mammals as a role model, the artificial hormone system(AHS) was designed to map tasks on processing elements using artificial hormones. In previous publications we presented the idea of an organic middleware and first theoretical results. As we want to run this middleware in an embedded scenario we will now present an implementation of the AHS written in pure ANSI C and show first real-world scenarios and results of test series.","PeriodicalId":142767,"journal":{"name":"2010 13th IEEE International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115767594","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}
Testing services offered at runtime is gaining more and more importance. This arises because the number of applications in which services don't know each other a priori grows and occurring faults can cause high costs. The approach proposed here uses testing to assure QoS properties like e.g. real-time features and functionality of services. A challenge of testing is not to overload the service providing systems. Furthermore tests also have to adapt automatically to the currently offered services as well as to the usage of these services. We present an approach for testing services, which fulfills these challenges and is based on a genetic algorithm. To rate a functional result, the majority vote is used.
{"title":"Test Case Generation for Non-functional and Functional Testing of Services","authors":"Simone Meixler, U. Brinkschulte","doi":"10.1109/ISORC.2010.20","DOIUrl":"https://doi.org/10.1109/ISORC.2010.20","url":null,"abstract":"Testing services offered at runtime is gaining more and more importance. This arises because the number of applications in which services don't know each other a priori grows and occurring faults can cause high costs. The approach proposed here uses testing to assure QoS properties like e.g. real-time features and functionality of services. A challenge of testing is not to overload the service providing systems. Furthermore tests also have to adapt automatically to the currently offered services as well as to the usage of these services. We present an approach for testing services, which fulfills these challenges and is based on a genetic algorithm. To rate a functional result, the majority vote is used.","PeriodicalId":142767,"journal":{"name":"2010 13th IEEE International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122654879","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}