Blockchain,like any other complex technology,needs a strong testing methodology to support its evolution in both research and development contexts.Setting up meaningful tests for permissionless blockchain technology i...Blockchain,like any other complex technology,needs a strong testing methodology to support its evolution in both research and development contexts.Setting up meaningful tests for permissionless blockchain technology is a notoriously complex task for several reasons:software is complex,a large number of nodes are involved,the network is non-ideal,etc.Developers usually adopt small virtual laboratories or costly real devnets based on real software.Researchers usually prefer simulations of a large number of nodes based on simplified models.In this paper,we aim to obtain the advantages of both approaches,i.e.,performing large,realistic,inexpensive,and flexible experiments,using real blockchain software within a virtual environment.To do that,we address the challenge of running large blockchain networks in a single physical machine,leveraging Linux and Docker.We analyze a number of problems that arise when large blockchain networks are emulated,and we provide technical solutions for all of them.Finally,we describe two experiences of emulating fairly large blockchain networks on a single machine:adopting both research-oriented and production-oriented software and involving more than 3000 containers.展开更多
Due to the rapid development of mobile Internet services, such as Skype and WeChat, traditional telecom services have suffered a large decline in the business volumes in recent years. Thus, telecom operators pay much ...Due to the rapid development of mobile Internet services, such as Skype and WeChat, traditional telecom services have suffered a large decline in the business volumes in recent years. Thus, telecom operators pay much attention to analyzing the changes of the enterprise performance, in order to adjust market strategies in time. In this paper, we propose a new methodology to analyze the operation data of telecom operators dynamically,which can characterize the changing process of the operating states and predict the developing trends. In particular, the proposed methodology contains two steps: migration pattern analysis and trajectory pattern analysis.Firstly, migration analysis is based on the changing of operating states between two points-in-time, which is referred to as the migration paths. Applying the clustering analysis to the migration paths can obtain the migration patterns, which characterize the changing feature of telecom operators during a short period, e.g. one month. Secondly, we combine a sequence of consecutive migration paths to obtain the migration trajectory. Through analyzing different trajectories based on the hierarchical cluster method and the Markov chain model, we obtain the trajectory patterns,which describe the changing progress during a relatively long period, e.g. one year. Based on the trajectory patterns, we can predict the possible performance changes. Finally, we apply the proposed method to a Chinese telecom operator for an empirical research, and has obtained a lot of development rules which provides insights into current telecom.展开更多
中国企业创新创业调查(Enterprise Survey for Innovation and Entrepreneurship in China,简称ESIEC)的主要目的之一,就是通过对中小微企业的调查填补中小企业创新数据缺失的空白。本文首先对创新测度和创新调查相关的理论和文献进行...中国企业创新创业调查(Enterprise Survey for Innovation and Entrepreneurship in China,简称ESIEC)的主要目的之一,就是通过对中小微企业的调查填补中小企业创新数据缺失的空白。本文首先对创新测度和创新调查相关的理论和文献进行了梳理,其次对ESIEC的问卷设计进行了介绍,然后对ESIEC的企业创新数据的基本事实进行了分析,最后用CDM(Crepon,Duguet,and Mairessec)模型分析了中小微企业中研发、创新和生产率之间的关系。结果表明,在ESIEC的中小微企业中,研发、创新和生产率之间的关系与文献结论一致。相比中国现有的创新方面的微观数据,本文所依托的ESIEC具有以下四个方面的突出优势:①涵盖多维度的创新测度和较为全面的创新方面的信息,不仅有与国际通用创新调查数据相同的调查信息,还考虑了中国的经济特色,包含了一些与高质量发展相关的指标;②调查对象包含了小微企业;③调查对象不仅包含制造业,还包含多种服务业;④与国际上很多微观层面的创新调查采用线上或电话调查不同,ESIEC采用了由受过严格训练的访员面对面调查企业负责人或高管的方式。总之,ESIEC数据可以被很好地用来分析中国中小微企业的创新活动。初步分析结果表明,基于ESIEC的创新分析结果与文献一致:①企业规模对企业的研发投入决策起着至关重要的作用;②研发促进了产品创新和流程创新;③产品创新和流程创新都能促进劳动生产率。因此,ESIEC数据具有良好的可靠性,并且可以与欧盟创新调查(CIS)和美国的年度商业调查(ABS)进行可比性分析。展开更多
基金supported by project SERICS(PE00000014)under the MUR National Recovery and Resilience Plan funded by the European Union-NextGenerationEU.
文摘Blockchain,like any other complex technology,needs a strong testing methodology to support its evolution in both research and development contexts.Setting up meaningful tests for permissionless blockchain technology is a notoriously complex task for several reasons:software is complex,a large number of nodes are involved,the network is non-ideal,etc.Developers usually adopt small virtual laboratories or costly real devnets based on real software.Researchers usually prefer simulations of a large number of nodes based on simplified models.In this paper,we aim to obtain the advantages of both approaches,i.e.,performing large,realistic,inexpensive,and flexible experiments,using real blockchain software within a virtual environment.To do that,we address the challenge of running large blockchain networks in a single physical machine,leveraging Linux and Docker.We analyze a number of problems that arise when large blockchain networks are emulated,and we provide technical solutions for all of them.Finally,we describe two experiences of emulating fairly large blockchain networks on a single machine:adopting both research-oriented and production-oriented software and involving more than 3000 containers.
基金partially supported by NSFC (71371034 and 71372194)Beijing Natural Science Foundation (9162011)
文摘Due to the rapid development of mobile Internet services, such as Skype and WeChat, traditional telecom services have suffered a large decline in the business volumes in recent years. Thus, telecom operators pay much attention to analyzing the changes of the enterprise performance, in order to adjust market strategies in time. In this paper, we propose a new methodology to analyze the operation data of telecom operators dynamically,which can characterize the changing process of the operating states and predict the developing trends. In particular, the proposed methodology contains two steps: migration pattern analysis and trajectory pattern analysis.Firstly, migration analysis is based on the changing of operating states between two points-in-time, which is referred to as the migration paths. Applying the clustering analysis to the migration paths can obtain the migration patterns, which characterize the changing feature of telecom operators during a short period, e.g. one month. Secondly, we combine a sequence of consecutive migration paths to obtain the migration trajectory. Through analyzing different trajectories based on the hierarchical cluster method and the Markov chain model, we obtain the trajectory patterns,which describe the changing progress during a relatively long period, e.g. one year. Based on the trajectory patterns, we can predict the possible performance changes. Finally, we apply the proposed method to a Chinese telecom operator for an empirical research, and has obtained a lot of development rules which provides insights into current telecom.
文摘中国企业创新创业调查(Enterprise Survey for Innovation and Entrepreneurship in China,简称ESIEC)的主要目的之一,就是通过对中小微企业的调查填补中小企业创新数据缺失的空白。本文首先对创新测度和创新调查相关的理论和文献进行了梳理,其次对ESIEC的问卷设计进行了介绍,然后对ESIEC的企业创新数据的基本事实进行了分析,最后用CDM(Crepon,Duguet,and Mairessec)模型分析了中小微企业中研发、创新和生产率之间的关系。结果表明,在ESIEC的中小微企业中,研发、创新和生产率之间的关系与文献结论一致。相比中国现有的创新方面的微观数据,本文所依托的ESIEC具有以下四个方面的突出优势:①涵盖多维度的创新测度和较为全面的创新方面的信息,不仅有与国际通用创新调查数据相同的调查信息,还考虑了中国的经济特色,包含了一些与高质量发展相关的指标;②调查对象包含了小微企业;③调查对象不仅包含制造业,还包含多种服务业;④与国际上很多微观层面的创新调查采用线上或电话调查不同,ESIEC采用了由受过严格训练的访员面对面调查企业负责人或高管的方式。总之,ESIEC数据可以被很好地用来分析中国中小微企业的创新活动。初步分析结果表明,基于ESIEC的创新分析结果与文献一致:①企业规模对企业的研发投入决策起着至关重要的作用;②研发促进了产品创新和流程创新;③产品创新和流程创新都能促进劳动生产率。因此,ESIEC数据具有良好的可靠性,并且可以与欧盟创新调查(CIS)和美国的年度商业调查(ABS)进行可比性分析。
