Estimating network effects in China’s mobile telecommunications

A model is proposed along with empirical investigation to prove the existence of network effects in China’s mobile telecommunications market. Futhernore, network effects on China’s mobile telecommunications are estimated with a dynamic model. The structural parameters are identified from regression coefficients and the results are analyzed and compared with another literature. Data and estimation issues are also discussed. Conclusions are drawn that network effects are significant in China’s mobile telecommunications market, and that ignoring network effects leads to bad policy making.

Drivers for Inter-city Innovation Networks Across Chinese Cities:Modelling Physical Versus Intangible Effects

Cross-region innovation is widely recognized as an important source of the long-term regional innovation capacity.In the recent past,a growing number of studies has investigated the network structure and mechanisms of cross-region innovation collaboration in various contexts.However,existing research mainly focuses on physical effects,such as geographical distance and high-speed railway connections.These studies ignore the intangible drivers in a changing environment,the more digitalized economy and the increasingly solidified innovation network structure.Thus,the focus of this study is on estimating determinants of innovation networks,especially on intangible drivers,which have been largely neglected so far.Using city-level data of Chinese patents(excluding Hong Kong,Macao,and Taiwan Province of China),we trace innovation networks across Chinese cities over a long period of time.By integrating a measure on Information and Communications Technology(ICT)development gap and network structural effects into the general proximity framework,this paper explores the changing mechanisms of Chinese innovation networks from a new perspective.The results show that the structure of cross-region innovation networks has changed in China.As mechanisms behind this development,the results confirm the increasingly important role of intangible drivers in Chinese inter-city innovation collaboration when controlling for effects of physical proximity,such as geographical distance.Since digitalization and coordinated development are the mainstream trends in China and other developing countries,these countries'inter-city innovation collaboration patterns will witness dramatic changes under the influence of intangible drivers.

Effects of Reduced Frequency on Network Configuration and Synchronization Transition

Synchronization of networked phase oscillators depends essentially on the correlation between the topological structure of the graph and the dynamical property of the elements. We propose the concept of ＇reduced frequency＇, a measure which can quantify natural frequencies of each pair of oscillators. Then we introduce an evolving network whose linking rules are controlled by its own dynamical property. The simulation results indicate that when the linking probability positively correlates with the reduced frequency, the network undergoes a first-order phase transition. Meanwhile, we discuss the circumstance under which an explosive synchronization can be ignited. The numerical results show that the peculiar butterfly shape correlation between frequencies and degrees of the nodes contributes to an explosive synchronization transition.

Wavelet network based predistortion method for wideband RF power amplifiers exhibiting memory effects

RF power amplifiers (PAs) are usually considered as memoryless devices in most existing predistortion techniques. Nevertheless, in wideband communication systems, PA memory effects can no longer be ignored and memoryless predistortion cannot linearize PAs effectively. After analyzing PA memory effects, a novel predistortion method based on wavelet networks (WNs) is proposed to linearize wideband RF power amplifiers. A complex wavelet network with tapped delay lines is applied to construct the predistorter and then a complex backpropagation algorithm is developed to train the predistorter parameters. The simulation results show that compared with the previously published feed-forward neural network predistortion method, the proposed method provides faster convergence rate and better performance in reducing out-of-band spectral regrowth.

Diffusion mechanism simulation of cloud manufacturing complex network based on cooperative game theory

Cloud manufacturing is a specific implementation form of the "Internet + manufacturing" strategy. Why and how to develop cloud manufacturing platform(CMP), however, remains the key concern of both platform operators and users. A microscopic model is proposed to investigate advantages and diffusion forces of CMP through exploration of its diffusion process and mechanism. Specifically, a three-stage basic evolution process of CMP is innovatively proposed. Then, based on this basic process, a more complex CMP evolution model has been established in virtue of complex network theory, with five diffusion forces identified. Thereafter, simulations on CMP diffusion have been conducted. The results indicate that, CMP possesses better resource utilization,user satisfaction, and enterprise utility. Results of simulation on impacts of different diffusion forces show that both the time required for CMP to reach an equilibrium state and the final network size are affected simultaneously by the five diffusion forces. All these analyses indicate that CMP could create an open online cooperation environment and turns out to be an effective implementation of the "Internet + manufacturing" strategy.

STUDY ON THE OPTIMIZATION OF TRANSPORT CONTROL POLICY IN COMMUNICATION NETWORK

In communication networks with policy-based Transport Control on-Demand (TCoD) function,the transport control policies play a great impact on the network effectiveness. To evaluate and optimize the transport policies in communication network,a policy-based TCoD network model is given and a comprehensive evaluation index system of the network effectiveness is put forward from both network application and handling mechanism perspectives. A TCoD network prototype system based on Asynchronous Transfer Mode/Multi-Protocol Label Switching (ATM/MPLS) is introduced and some experiments are performed on it. The prototype system is evaluated and analyzed with the comprehensive evaluation index system. The results show that the index system can be used to judge whether the communication network can meet the application requirements or not,and can provide references for the optimization of the transport policies so as to improve the communication network effectiveness.

Analysis of coseismic effect on temperature in the Three Gorges well network

Through the Three Gorges well network, we examine different coseismic changes in water temperature caused by local earthquakes since 2008, and offer a mechanistic explanation.The relations between the coseismic changes in water temperature and the parameters of distant and local earthquakes are deduced.

COMMENTS ON THE HOLISTIC ACTION OF ACUPUNCTURE IN VIEW OF ITS INFLUENCE ON NERVE-ENDOCRINE-IMMUNE NETWORK

In the present paper, the author makes some comments on the holistic action of acupuncture from the regulative effect on the nerve-endocrine-immune network, and the close relationship between the nerve-endocrine-immune network and the meridian-collateral system of TCM. The wholism concept of TCM refers to the organism being an integrated entirety, and the regulatory effect of acupuncture on functional activities of the organism relies on the integral connection of the acupoint-meridian-collateral-zangfu-organ system. When stimulated with acupuncture, the human body will brings its potential force into full play in preventing and treating diseases.

Measuring Effectiveness in E-Commerce Networks

The revolution of information technology within the p ast twenty years has dramatically changed the picture of our economy. Numerous n ew possibilities of communication have let competition advantages for many compa nies and even advantageous macroeconomic consequences emerge on national and international level. Through newly developed information technologies the knowl edge base of market participants improves with a concurrent reduction of the inf ormation obtaining costs. As a result considerable competition advantages develo p for those companies acting in E-commerce networks. These advantages of the la test development lead to macroeconomic effects on national level, if the effecti veness and efficiency increasing possibilities are used more strongly than in ot her countries. Positive international effects arise since the allocation effic iency is increased through intensified competition between different market pa rticipants in various countries. This in turn leads to an increase in wo rldwide prosperity. This causal chain however is not yet realistic to the whole extent, as such an i ncreased transparency of information is not necessarily accepted by all market p articipants. Otherwise a considerable productivity increase would already have o ccurred in industrial countries. Overall the question arises, whether the change s in the competition situation make single enterprises technically more effectiv e, concurrently however deteriorate the efficiency of the entire market through informational asymmetries. To answer these and further questions and to measure the effectiveness and effic iency of various E-commerce networks an interdisciplinary analysis platform is to be developed. With the help of this platform, it should be possible to examin e single and macroeconomic questions, reveal temporal connections and to analyse aspects of business management and national economy, information management, em ployment politics and finance politics. For this, various part-models for the i ndividual knowledge disciplines have to be generated and brought together in the platform. This platform allows various users to make the right decisions (effec tiveness) with the help of the developed models and to competently estimate the effects (efficiency). Currently models of the individual knowledge disciplines (business management, e conomics, computer science) are being developed within the research project EEE. con. This project deals with the question of Supply Chain Management (SCM), E-P rocurement, with the implementation of inter-organisational information systems , as well as various market, competition and organisation models. The department of economics and computer science from Prof. Dr.-Ing. habil. W. Dangelmaier particularly deals with the development of an agent controlled SCM- communication model which is part of the E-commerce analysis platform. Both are described in this paper. Furthermore, a unified modelling language in order to allow a prototypic implementation of the analysis tool and to make the work with other project participants and external participants easier is decided upon wit hin this project.

Adaptive evolvement of information age C^4ISR structure

Command, control, communication, computing, intel- ligence, surveillance and reconnaissance （C^4ISR） in information age is a complex system whose structure always changes ac- tively or passively during the warfare. Therefore, it is important to optimize the structure, especially in ambiguous and quick-tempo modern warfare. This paper proposes an adaptive evolvement mechanism for the C^4ISR structure to survive the changeable warfare. Firstly, the information age C^4ISR structure is defined and modeled based on the complex network theory. Secondly, taking the observe, orient, decide and act （OODA） model into consideration, four kinds of loops in the C^4ISR structure are pro- posed and their coefficient of networked effects （CNE） is further defined. Then, the adaptive evolvement mechanisms of the four kinds of loops are presented respectively. Finally, taking the joint air-defense C^4ISR as an example, simulation experiments are im- plemented, which validate the evolvement mechanism and show that the information age C41SR structure has some characteristics of small-world network and scale-free network.

Understanding cashless payments in India

Background:This paper analyzes India’s gradual transition towards a cashless economy.Methods:We present a theoretical model that evaluates decisions by consumers and sellers to adopt cashless payments.We then use data from surveys conducted in 2011 and 2014(from World Bank’s Global Findex),as well as household and enterprise surveys conducted in 2009-2010 to estimate the amount of cashless transactions prevalent in India and identify the avenues that are successful and those that are not.We analyze instruments(cards versus point-of-sale versus mobile),micro units(individuals versus households versus retailers),and sectors to identify and estimate the enablers and bottlenecks.Results:We find that the most crucial enabler of cashless payments are inflows of funds into the accounts.Conclusion:Based on our findings,we suggest possible policy interventions.

Blockchain Management in Smart Grid

Power Supply and Smart Grid represent specific business,which must be managed by permissioned(private)blockchain.Despite its disadvantages-time consuming,expensive,and losing from network effect-the permissioned blockchain offers balance,guarantees stability,and provides physical limitations for usage of validating nodes only in the network.The management of permissioned blockchain is necessary for tracing the processes in it.The author has represented the moment following topics:the idea for applying blockchain in business environment,blockchain technology-as a linked list with a new key on each step,node structure and information models for node management with a large granularity,detail models for node management with accent on configuration and performance and managed objects classes for installation of blockchain network with accent on security and performance,models for blockchain network management and five scenarios for blockchain transactions management.The paper represents a stage of project Blockchain in Smart Grid:describing of Managed Objects classes for functional areas of blockchain life cycle:Provision,Configuration,Maintenance,Security(developed),Accounting,Performance,and Subscriber control.The author uses the life cycle of telecommunications networks as a reference.The models are designed for user interface developers,university professors,and students.

ANALYSIS OF FREEMIUM BUSINESS MODEL CONSIDERING NETWORK EXTERNALITIES AND CONSUMER UNCERTAINTY

An emerging business model increasingly used by companies in the online software market is to provide both a free basic version and a paid premium version for a service or a product to customers. Such a setting is often called freemium model. The existence of the free version can reduce the customer uncertainty regarding the evaluation of the commercial software and make use of network effect to improve the firm＇s profit. However, the freemium model may also have the cannibalization effect which can hurt the profit. Hence, the from needs to determine the optimal content for the free version and the optimal price for the premium version to maximize its profit. In this paper, thst, we obtain the optimal decisions of the freemium model and their properties. Second, we compare the freemium model with the traditional charge-for-everything model that all content of the product need to be charged in terms of the profit, customer welfare, and social welfare. The results show that when customer underestimates the value of the software significantly and the true value of the software is high enough, the freemium model can generate higher profit, higher customer welfare, and higher social welfare. Otherwise, the freemium model may not deliver the desired results.

A case study on the shareholder network effect of stock market data:An SARMA approach

One of the key research problems in financial markets is the investigation of inter-stock dependence.A good understanding in this regard is crucial for portfolio optimization.To this end,various econometric models have been proposed.Most of them assume that the random noise associated with each subject is independent.However,dependence might still exist within this random noise.Ignoring this valuable information might lead to biased estimations and inaccurate predictions.In this article,we study a spatial autoregressive moving average model with exogenous covariates.Spatial dependence from both response and random noise is considered simultaneously.A quasi-maximum likelihood estimator is developed,and the estimated parameters are shown to be consistent and asymptotically normal.We then conduct an extensive analysis of the proposed method by applying it to the Chinese stock market data.

The abundance effect on network nestedness is stronger for parasitic than herbivory interactions

It has been suggested that the importance of network architecture to species diversity and stability should be based on preference networks(comprised of niche differentiations),rather than observational networks,because species abundance may significantly affect interaction frequencies.Considering that resource abundance is usually greater for herbivores than parasites,we hypothesize that the abundance effect is stronger for parasitic than herbivory interactions.To test this hypothesis,we collected 80 quantitative observational networks including 34 herbivorous and 46 parasitic networks from the published literature,and derived preference networks by removing the effects of species abundance.We then determined the network nestedness using both weighted NODF and spectral radius.We also determined species degree distribution,interaction evenness,weighted connectance and robustness for both observational and preference networks.The observational networks(including both herbivory and parasitic networks)were more nested judged by weighted NODF than spectral radius.Preference networks were less nested for parasitic than herbivory networks in terms of both weighted NODF and spectral radius,possibly because removing the abundance effect increased interaction evenness.These trends indicate that the abundance effect on network nestedness is stronger for parasitic than herbivory networks.Weighted connectance and robustness were greater in most preference networks than observational networks,indicating that preference networks may have high network stability and community persistence compared with observational ones.The data indicate that future network analyses should not only address the structural difference between mutualistic and antagonistic interactions,but also between herbivory and parasitic interactions.

Facebook and Tencent Data Fit a Cube Law Better than Metcalfe’s Law

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.

Tencent and Facebook Data Validate Metcalfe＇s Law

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.

VALUE-ADDED SERVICE INVESTING AND PRICING STRATEGIES FOR A TWO-SIDED PLATFORM UNDER INVESTING RESOURCE CONSTRAINT

Investing on value-added service （VAS） amplifies users＇ participation and platform profit. However, the investing resource is usually limited in practice. This paper investigates VAS investing and pricing strategies for a two-sided platform under investing resource constraint. We reveal that with VAS investment, Subsidizing can still be done to enlarge users＇ demand, even when the investing cost becomes higher. For optimal pricing strategies, the network effect will be the dominating determinant if the gap between two marginal cross-side benefits （i.e. the benefit that users obtain when each new user join the other side of the platform） is large. Interestingly, we show that with the increase of the marginal investing cost, users might either be priced higher or lower. If the marginal investing cost increases to a high level, and the gap between the two marginal cross-side benefits is large, lowering the access fee for users possessing the higher eross-side network effect does not necessarily compensate more profit loss caused by higher cost. Moreover, after VAS is developed, raising the access fee for those whose marginal investing benefit is large does not necessarily generate more profit as well. The opposite strategy further enlarges users＇ utility, and promotes the investment to benefit more users.