Pub Date : 2013-12-02DOI: 10.1109/CloudCom.2013.103
Juan Angel Lorenzo del Castillo, Kate Mallichan, Yahya Al-Hazmi
There is an increasing number of cloud platforms emerging in both academia and industry. They often federate resources from multiple infrastructures in order to benefit from the unique features that each presents. After introducing the main capabilities and features of OpenStack, this article addresses the integration of OpenStack-based platforms into larger, heterogeneous multi-cloud infrastructures, taking the EU FP7 BonFIRE project as an integration use case. Ultimately, we aim to contribute to the state of the art and provide guidelines to integrators looking to federate Open Stack testbeds into more complex architectures.
{"title":"OpenStack Federation in Experimentation Multi-cloud Testbeds","authors":"Juan Angel Lorenzo del Castillo, Kate Mallichan, Yahya Al-Hazmi","doi":"10.1109/CloudCom.2013.103","DOIUrl":"https://doi.org/10.1109/CloudCom.2013.103","url":null,"abstract":"There is an increasing number of cloud platforms emerging in both academia and industry. They often federate resources from multiple infrastructures in order to benefit from the unique features that each presents. After introducing the main capabilities and features of OpenStack, this article addresses the integration of OpenStack-based platforms into larger, heterogeneous multi-cloud infrastructures, taking the EU FP7 BonFIRE project as an integration use case. Ultimately, we aim to contribute to the state of the art and provide guidelines to integrators looking to federate Open Stack testbeds into more complex architectures.","PeriodicalId":198053,"journal":{"name":"2013 IEEE 5th International Conference on Cloud Computing Technology and Science","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122924240","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 : 2013-12-02DOI: 10.1109/CloudCom.2013.16
M. Chalkiadaki, K. Magoutis
In this paper we describe the architecture of a quality-of-service (QoS) infrastructure for achieving controlled application performance over the Cassandra distributed storage system. We present an implementation of our architecture and provide results from an evaluation using the Yahoo Cloud Serving Benchmark (YCSB) on the Amazon EC2 Cloud. A key focus of this paper is on a QoS-aware measurement-driven provisioning methodology. Our evaluation provides evidence that the methodology is effective in estimating application resource requirements and thus in achieving the type of controlled performance required by data intensive performance-critical applications. While our architecture is implemented and evaluated in the context of the Cassandra distributed storage system, its principles are general and can be applied to a variety of NoSQL systems.
{"title":"Managing Service Performance in the Cassandra Distributed Storage System","authors":"M. Chalkiadaki, K. Magoutis","doi":"10.1109/CloudCom.2013.16","DOIUrl":"https://doi.org/10.1109/CloudCom.2013.16","url":null,"abstract":"In this paper we describe the architecture of a quality-of-service (QoS) infrastructure for achieving controlled application performance over the Cassandra distributed storage system. We present an implementation of our architecture and provide results from an evaluation using the Yahoo Cloud Serving Benchmark (YCSB) on the Amazon EC2 Cloud. A key focus of this paper is on a QoS-aware measurement-driven provisioning methodology. Our evaluation provides evidence that the methodology is effective in estimating application resource requirements and thus in achieving the type of controlled performance required by data intensive performance-critical applications. While our architecture is implemented and evaluated in the context of the Cassandra distributed storage system, its principles are general and can be applied to a variety of NoSQL systems.","PeriodicalId":198053,"journal":{"name":"2013 IEEE 5th International Conference on Cloud Computing Technology and Science","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125696897","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 : 2013-12-02DOI: 10.1109/CloudCom.2013.124
Marouen Mechtri, D. Zeghlache, E. Zekri, I. Marshall
This paper presents a Cloud Networking Gateway (CNG) Manager, to enable networking of distributed cloud resources by authorized customers and to provide network control and configuration capabilities. The CNG Manager interconnects virtual machines, acquired from distributed heterogeneous resources and multiple providers, using generic gateways according to user connectivity requests. The CNG Manager is integrated with a "Cloud Broker" architecture for evaluation in the multiple providers context. The proposed framework extends and supports the current state of the art in cloud and software defined networks technologies with compatible connectivity control and management capabilities.
{"title":"Inter-cloud Networking Gateway Architecture","authors":"Marouen Mechtri, D. Zeghlache, E. Zekri, I. Marshall","doi":"10.1109/CloudCom.2013.124","DOIUrl":"https://doi.org/10.1109/CloudCom.2013.124","url":null,"abstract":"This paper presents a Cloud Networking Gateway (CNG) Manager, to enable networking of distributed cloud resources by authorized customers and to provide network control and configuration capabilities. The CNG Manager interconnects virtual machines, acquired from distributed heterogeneous resources and multiple providers, using generic gateways according to user connectivity requests. The CNG Manager is integrated with a \"Cloud Broker\" architecture for evaluation in the multiple providers context. The proposed framework extends and supports the current state of the art in cloud and software defined networks technologies with compatible connectivity control and management capabilities.","PeriodicalId":198053,"journal":{"name":"2013 IEEE 5th International Conference on Cloud Computing Technology and Science","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125076486","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 : 2013-12-02DOI: 10.1109/CloudCom.2013.17
Wei Cai, Conghui Zhou, Victor C. M. Leung, Min Chen
Mobile cloud gaming provides a whole new service model for the video game industry to overcome the intrinsic restrictions of mobile devices and piracy issues. However, the diversity of end-user devices and frequent changes in network quality of service and cloud responses result in unstable Quality of Experience (QoE) for game players. A cognitive cloud gaming platform, which could overcome the above problem by learning about the game player's environment and adapting the cloud gaming service accordingly, does not currently exist. To fill this void, we design and implement a component-based gaming platform that supports click-and-play, intelligent resource allocation and partial offline execution, to provide cognitive capabilities across the cloud gaming system. Extensive experiments have been performed to show that intelligent partitioning leads to better system performance, such as overall latency.
{"title":"A Cognitive Platform for Mobile Cloud Gaming","authors":"Wei Cai, Conghui Zhou, Victor C. M. Leung, Min Chen","doi":"10.1109/CloudCom.2013.17","DOIUrl":"https://doi.org/10.1109/CloudCom.2013.17","url":null,"abstract":"Mobile cloud gaming provides a whole new service model for the video game industry to overcome the intrinsic restrictions of mobile devices and piracy issues. However, the diversity of end-user devices and frequent changes in network quality of service and cloud responses result in unstable Quality of Experience (QoE) for game players. A cognitive cloud gaming platform, which could overcome the above problem by learning about the game player's environment and adapting the cloud gaming service accordingly, does not currently exist. To fill this void, we design and implement a component-based gaming platform that supports click-and-play, intelligent resource allocation and partial offline execution, to provide cognitive capabilities across the cloud gaming system. Extensive experiments have been performed to show that intelligent partitioning leads to better system performance, such as overall latency.","PeriodicalId":198053,"journal":{"name":"2013 IEEE 5th International Conference on Cloud Computing Technology and Science","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132082423","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 : 2013-12-02DOI: 10.1109/CloudCom.2013.28
Xiaolong Cui, Xuelian Lin, Chunming Hu, Richong Zhang, Chengzhang Wang
MapReduce is a widely used programming model for large scale data processing. In order to estimate the performance of MapReduce job and analyze the bottleneck of MapReduce job, a practical performance model for MapReduce is needed. Many works have been done on modeling the performance of MapReduce jobs. However, existing performance models ignore some important factors, such as I/O congestions and task failures over cluster, which may significantly change the execution costs of MapReduce job. This paper, aiming at predicting the execution time of a MapReduce job, presents an enhanced performance model that takes the resource contention and task failures into consideration. In addition, the experimental results show that the model is more accurate than those without considering the contention and failure factors.
{"title":"Modeling the Performance of MapReduce under Resource Contentions and Task Failures","authors":"Xiaolong Cui, Xuelian Lin, Chunming Hu, Richong Zhang, Chengzhang Wang","doi":"10.1109/CloudCom.2013.28","DOIUrl":"https://doi.org/10.1109/CloudCom.2013.28","url":null,"abstract":"MapReduce is a widely used programming model for large scale data processing. In order to estimate the performance of MapReduce job and analyze the bottleneck of MapReduce job, a practical performance model for MapReduce is needed. Many works have been done on modeling the performance of MapReduce jobs. However, existing performance models ignore some important factors, such as I/O congestions and task failures over cluster, which may significantly change the execution costs of MapReduce job. This paper, aiming at predicting the execution time of a MapReduce job, presents an enhanced performance model that takes the resource contention and task failures into consideration. In addition, the experimental results show that the model is more accurate than those without considering the contention and failure factors.","PeriodicalId":198053,"journal":{"name":"2013 IEEE 5th International Conference on Cloud Computing Technology and Science","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132050807","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 : 2013-12-02DOI: 10.1109/CloudCom.2013.169
R. Hammad, M. Odeh, Z. Khan
The e-Learning domain is evolving rapidly due to a number of factors and amongst these are the two key factors: i) availability of new ICT tools and technologies such as cloud computing, ontologies and smart phones, and ii) application of various learning theories and the development of new learning models. The latter is anticipated to generate new sets of requirements for the development of new e-Learning for the cloud environment. This paper is an attempt towards developing a generic requirements model for hybrid cloud-based e-Learning systems with particular reference to e-learning systems' requirements in general, pedagogical requirements, technical requirements including non-functional requirements, and the mapping of these requirements to cloud-based e-learning environments.
{"title":"Towards A Generic Requirements Model for Hybrid and Cloud-based e-Learning Systems","authors":"R. Hammad, M. Odeh, Z. Khan","doi":"10.1109/CloudCom.2013.169","DOIUrl":"https://doi.org/10.1109/CloudCom.2013.169","url":null,"abstract":"The e-Learning domain is evolving rapidly due to a number of factors and amongst these are the two key factors: i) availability of new ICT tools and technologies such as cloud computing, ontologies and smart phones, and ii) application of various learning theories and the development of new learning models. The latter is anticipated to generate new sets of requirements for the development of new e-Learning for the cloud environment. This paper is an attempt towards developing a generic requirements model for hybrid cloud-based e-Learning systems with particular reference to e-learning systems' requirements in general, pedagogical requirements, technical requirements including non-functional requirements, and the mapping of these requirements to cloud-based e-learning environments.","PeriodicalId":198053,"journal":{"name":"2013 IEEE 5th International Conference on Cloud Computing Technology and Science","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131895443","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 : 2013-12-02DOI: 10.1109/CloudCom.2013.43
José Simão, L. Veiga
Current clouds SLAs include compensation for customers (i.e. resource renters) with credits when average availability drops below a certain point. However, this credit scheme is too inflexible because consumers lose a non measurable quantity of performance and are only compensated later (i.e. in the next charging cycle). We propose to schedule cloud isolation and execution units, i.e. virtual machines (VMs), driven by the partial utility of applying a certain amount of resources (CPU, memory or bandwidth) to a given VM. This partial utility metric, specified by the customer, allows the provider to transfer resources between VMs. This is particularly relevant for private clouds where resources are not so abundant. We have defined a cost model that incorporates the partial utility the client gives to a certain level of depreciation when VMs are allocated in an over commit environment. CloudSim, a state of the art cloud simulator, was extended to support our partial utility-driven scheduling model. Using simulation scenarios with synthetic and real workloads, we show that our proposed scheduling strategy brings benefits to providers (i.e. revenue, resource utilization) and clients (i.e. workloads' execution time) by incorporating a SLA-based depreciation of computational power, allowing for more VMs to be allocated.
{"title":"Flexible SLAs in the Cloud with a Partial Utility-Driven Scheduling Architecture","authors":"José Simão, L. Veiga","doi":"10.1109/CloudCom.2013.43","DOIUrl":"https://doi.org/10.1109/CloudCom.2013.43","url":null,"abstract":"Current clouds SLAs include compensation for customers (i.e. resource renters) with credits when average availability drops below a certain point. However, this credit scheme is too inflexible because consumers lose a non measurable quantity of performance and are only compensated later (i.e. in the next charging cycle). We propose to schedule cloud isolation and execution units, i.e. virtual machines (VMs), driven by the partial utility of applying a certain amount of resources (CPU, memory or bandwidth) to a given VM. This partial utility metric, specified by the customer, allows the provider to transfer resources between VMs. This is particularly relevant for private clouds where resources are not so abundant. We have defined a cost model that incorporates the partial utility the client gives to a certain level of depreciation when VMs are allocated in an over commit environment. CloudSim, a state of the art cloud simulator, was extended to support our partial utility-driven scheduling model. Using simulation scenarios with synthetic and real workloads, we show that our proposed scheduling strategy brings benefits to providers (i.e. revenue, resource utilization) and clients (i.e. workloads' execution time) by incorporating a SLA-based depreciation of computational power, allowing for more VMs to be allocated.","PeriodicalId":198053,"journal":{"name":"2013 IEEE 5th International Conference on Cloud Computing Technology and Science","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122023199","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 : 2013-12-02DOI: 10.1109/CloudCom.2013.102
D. Bernstein, Y. Demchenko
This paper presents the current work of the IEEE Intercloud Testbed project. The notion of an Intercloud has been an active research topic. Within the IEEE several researchers formed a Standards Working Group (IEEE P2302) where a specific set of conventions, formats, and protocols were proposed. It was decided by those in the Standards Working Group that due to the scale, variability of component Compute Clouds, and lack of insight into extremely large Compute Cloud operational issues, such a system could not realistically be fully defined without live experimentation. Therefore it was decided to set up a specifically structured organization within the IEEE in parallel to the Standards Working Group, to provide a structure for a live, experimental testbed. This paper describes the innovative organizational structure and various policies were used to provide the desire context. Also covered are how we sorted the issues around governance of the namespace, and the technical details of reference "Root" and "Exchange" functions. Ongoing work includes the plan to bootstrap the new testbed.
{"title":"The IEEE Intercloud Testbed -- Creating the Global Cloud of Clouds","authors":"D. Bernstein, Y. Demchenko","doi":"10.1109/CloudCom.2013.102","DOIUrl":"https://doi.org/10.1109/CloudCom.2013.102","url":null,"abstract":"This paper presents the current work of the IEEE Intercloud Testbed project. The notion of an Intercloud has been an active research topic. Within the IEEE several researchers formed a Standards Working Group (IEEE P2302) where a specific set of conventions, formats, and protocols were proposed. It was decided by those in the Standards Working Group that due to the scale, variability of component Compute Clouds, and lack of insight into extremely large Compute Cloud operational issues, such a system could not realistically be fully defined without live experimentation. Therefore it was decided to set up a specifically structured organization within the IEEE in parallel to the Standards Working Group, to provide a structure for a live, experimental testbed. This paper describes the innovative organizational structure and various policies were used to provide the desire context. Also covered are how we sorted the issues around governance of the namespace, and the technical details of reference \"Root\" and \"Exchange\" functions. Ongoing work includes the plan to bootstrap the new testbed.","PeriodicalId":198053,"journal":{"name":"2013 IEEE 5th International Conference on Cloud Computing Technology and Science","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114944822","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 : 2013-12-02DOI: 10.1109/CloudCom.2013.65
José Simão, N. Rameshan, L. Veiga
Cloud platforms are becoming more prevalent in every computational domain, particularly in e-Science. A typical scientific workload will have a long execution time or be data intensive. Providing an execution environment for these applications, which belong to different tenants, has to deal with the horizontal scaling of execution flows (i.e. threads) and an effective allocation of resources that takes into account the effective progress made by each tenant. While this is trivial for Bag-of-Tasks and embarrassingly parallel jobs, it is hard for HPC single-process multi-threaded applications because they cannot be scaled up automatically just by adding more virtual machines to execute the workload. In this paper we present MengTian, a distributed execution environment or platform capable of addressing the issues above. It encompasses several extensions to the Java execution environment, ranging from middleware to the virtual machine code and libraries. Our Java-based platform provides a Single System Image abstraction supported by a Partially Global Address Space to transparently spawn threads across a cluster of machines. It monitors progress with different levels-of-detail and accounts and restricts resource consumption. The overall goal is to redistribute resources among different JVM instances, increasing the unitary outcome of the progress vs. resource usage ratio over time.
{"title":"Resource-Aware Scaling of Multi-threaded Java Applications in Multi-tenancy Scenarios","authors":"José Simão, N. Rameshan, L. Veiga","doi":"10.1109/CloudCom.2013.65","DOIUrl":"https://doi.org/10.1109/CloudCom.2013.65","url":null,"abstract":"Cloud platforms are becoming more prevalent in every computational domain, particularly in e-Science. A typical scientific workload will have a long execution time or be data intensive. Providing an execution environment for these applications, which belong to different tenants, has to deal with the horizontal scaling of execution flows (i.e. threads) and an effective allocation of resources that takes into account the effective progress made by each tenant. While this is trivial for Bag-of-Tasks and embarrassingly parallel jobs, it is hard for HPC single-process multi-threaded applications because they cannot be scaled up automatically just by adding more virtual machines to execute the workload. In this paper we present MengTian, a distributed execution environment or platform capable of addressing the issues above. It encompasses several extensions to the Java execution environment, ranging from middleware to the virtual machine code and libraries. Our Java-based platform provides a Single System Image abstraction supported by a Partially Global Address Space to transparently spawn threads across a cluster of machines. It monitors progress with different levels-of-detail and accounts and restricts resource consumption. The overall goal is to redistribute resources among different JVM instances, increasing the unitary outcome of the progress vs. resource usage ratio over time.","PeriodicalId":198053,"journal":{"name":"2013 IEEE 5th International Conference on Cloud Computing Technology and Science","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116259108","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 : 2013-12-02DOI: 10.1109/CloudCom.2013.100
J. Prüfer
This paper applies economic governance theory to the cloud computing industry. We analyze which governance institution may be best suited to solve the problems stemming from asymmetric information about the true level of data protection, security, and accountability offered by cloud service providers. We conclude that certification agencies - private, independent organizations which award certificates to cloud service providers meeting certain technical and organizational criteria - are the optimal institution available. Those users with high valuation for accountability will be willing to pay more for the services of certified providers, whereas other users may patronize uncertified providers.
{"title":"How to Govern the Cloud? Characterizing the Optimal Enforcement Institution that Supports Accountability in Cloud Computing","authors":"J. Prüfer","doi":"10.1109/CloudCom.2013.100","DOIUrl":"https://doi.org/10.1109/CloudCom.2013.100","url":null,"abstract":"This paper applies economic governance theory to the cloud computing industry. We analyze which governance institution may be best suited to solve the problems stemming from asymmetric information about the true level of data protection, security, and accountability offered by cloud service providers. We conclude that certification agencies - private, independent organizations which award certificates to cloud service providers meeting certain technical and organizational criteria - are the optimal institution available. Those users with high valuation for accountability will be willing to pay more for the services of certified providers, whereas other users may patronize uncertified providers.","PeriodicalId":198053,"journal":{"name":"2013 IEEE 5th International Conference on Cloud Computing Technology and Science","volume":"755 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117007202","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：