Metcalfe’s law states that the value of a network grows as the square of the number of its users(V■N^(2)),which was validated by actual data of Facebook and Tencent in 2013–2015.Since then,the users and the values ...Metcalfe’s law states that the value of a network grows as the square of the number of its users(V■N^(2)),which was validated by actual data of Facebook and Tencent in 2013–2015.Since then,the users and the values of Facebook and Tencent have increased significantly.Is Metcalfe’s law still valid?This paper leverages the latest data of Facebook and Tencent to fit the network effect laws and makes the following observations:1)actual data of network values fit a cube law(V■N^(3))better than Metcalfe’s law;2)actual data of network costs fit a cube law;3)actual data of network sizes show a growth trend matching the netoid function well.We also discuss the underlying factors affecting such observations and the generality of the network effect laws.展开更多
目前正快速发展的社区医疗服务站成为了在人们的生活中发挥着越来越重要的作用,本文便详细地描述了开发医药信息管理系统的需求分析、系统分析、数据流程分析、功能设计等内容。系统以C#语言开发,并使用Microsoft Visual Studio 2010平...目前正快速发展的社区医疗服务站成为了在人们的生活中发挥着越来越重要的作用,本文便详细地描述了开发医药信息管理系统的需求分析、系统分析、数据流程分析、功能设计等内容。系统以C#语言开发,并使用Microsoft Visual Studio 2010平台和SQL Server 2008数据库,实现了信息管理的用户管理、库存管理、药品管理、查询功能以及出库单入库单等管理,并经过在本机windows7系统上运行测试可以很好的应用。展开更多
In 1980s, Robert Metcalfe, the inventor of Ethernet, proposed a formulation of network value in terms of the network size （the number of nodes of the network）, which was later named as Metcalfe＇s law. The law state...In 1980s, Robert Metcalfe, the inventor of Ethernet, proposed a formulation of network value in terms of the network size （the number of nodes of the network）, which was later named as Metcalfe＇s law. The law states that the value V of a network is proportional to the square of the size n of the network, i.e., V α n2. Metcalfe＇s law has been influential and an embodiment of the network effect concept. It also generated many controversies. Some scholars went so far as to state ＂Metcalfe＇s law is wrong＂ and ＂dangerous＂. Some other laws have been proposed, including Sarnoff＇s law （V α n）, Odlyzko＇s law （Vcx nlog（n））, and Reed＇s law （V o〈 2n）. Despite these arguments, for 30 years, no evidence based on real data was available for or against Metcalfe＇s law. The situation was changed in late 2013, when Metcalfe himself used Facebook＇s data over the past 10 years to show a good fit for Metcalfe＇s law. In this paper, we expand Metcalfe＇s results by utilizing the actual data of Tencent （China＇s largest social network company） and Facebook （the world＇s largest social network company）. Our results show that： 1） of the four laws of network effect, Metcalfe＇s law by far fits the actual data the best; 2） both Tencent and Facebook data fit Metcalfe＇s law quite well; 3） the costs of Tencent and Facebook are proportional to the squares of their network sizes, not linear; and 4） the growth trends of Tencent and Facebook monthly active users fit the netoid function well.展开更多
基金the China Postdoctoral Science Foundation under Grant No.2021M693227.
文摘Metcalfe’s law states that the value of a network grows as the square of the number of its users(V■N^(2)),which was validated by actual data of Facebook and Tencent in 2013–2015.Since then,the users and the values of Facebook and Tencent have increased significantly.Is Metcalfe’s law still valid?This paper leverages the latest data of Facebook and Tencent to fit the network effect laws and makes the following observations:1)actual data of network values fit a cube law(V■N^(3))better than Metcalfe’s law;2)actual data of network costs fit a cube law;3)actual data of network sizes show a growth trend matching the netoid function well.We also discuss the underlying factors affecting such observations and the generality of the network effect laws.
文摘目前正快速发展的社区医疗服务站成为了在人们的生活中发挥着越来越重要的作用,本文便详细地描述了开发医药信息管理系统的需求分析、系统分析、数据流程分析、功能设计等内容。系统以C#语言开发,并使用Microsoft Visual Studio 2010平台和SQL Server 2008数据库,实现了信息管理的用户管理、库存管理、药品管理、查询功能以及出库单入库单等管理,并经过在本机windows7系统上运行测试可以很好的应用。
文摘In 1980s, Robert Metcalfe, the inventor of Ethernet, proposed a formulation of network value in terms of the network size （the number of nodes of the network）, which was later named as Metcalfe＇s law. The law states that the value V of a network is proportional to the square of the size n of the network, i.e., V α n2. Metcalfe＇s law has been influential and an embodiment of the network effect concept. It also generated many controversies. Some scholars went so far as to state ＂Metcalfe＇s law is wrong＂ and ＂dangerous＂. Some other laws have been proposed, including Sarnoff＇s law （V α n）, Odlyzko＇s law （Vcx nlog（n））, and Reed＇s law （V o〈 2n）. Despite these arguments, for 30 years, no evidence based on real data was available for or against Metcalfe＇s law. The situation was changed in late 2013, when Metcalfe himself used Facebook＇s data over the past 10 years to show a good fit for Metcalfe＇s law. In this paper, we expand Metcalfe＇s results by utilizing the actual data of Tencent （China＇s largest social network company） and Facebook （the world＇s largest social network company）. Our results show that： 1） of the four laws of network effect, Metcalfe＇s law by far fits the actual data the best; 2） both Tencent and Facebook data fit Metcalfe＇s law quite well; 3） the costs of Tencent and Facebook are proportional to the squares of their network sizes, not linear; and 4） the growth trends of Tencent and Facebook monthly active users fit the netoid function well.
