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Model-based groupware solution for distributed real-time collaborative 4D planning via teamwork
Construction planning plays a fundamental role in construction project management that requires team working among planners from a diverse range of disciplines and in geographically dispersed working situations. Model-based four-dimensional (4D) computer-aided design (CAD) groupware, though considered a possible approach to supporting collaborative planning, is still short of effective collaborative mechanisms for teamwork due to methodological, technological and social challenges. Targeting this problem, this paper proposes a model-based groupware solution to enable a group of multidisciplinary planners to perform real-time collaborative 4D planning across the Internet. In the light of the interactive definition method, and its computer-supported collaborative work (CSCW) design analysis, the paper discusses the realization of interactive collaborative mechanisms from software architecture, application mode, and data exchange protocol. These mechanisms have been integrated into a groupware solution, which was validated by a planning team in a truly geographically dispersed condition. Analysis of the validation results revealed that the proposed solution is feasible for real-time collaborative 4D planning to gain a robust construction plan through collaborative teamwork. The realization of this solution triggers further considerations about its enhancement for wider
groupware applications
Quasiparticle scattering in two dimensional helical liquid
We study the quasiparticle interference (QPI) patterns caused by scattering
off nonmagnetic, magnetic point impurities, and edge impurities, separately, in
a two dimensional helical liquid, which describes the surface states of a
topological insulator. The unique features associated with hexagonal warping
effects are identified in the QPI patterns of charge density with nonmagnetic
impurities and spin density with magnetic impurities. The symmetry properties
of the QPI patterns can be used to determine the symmetry of microscopic
models. The Friedel oscillation is calculated for edge impurities and the decay
of the oscillation is not universal, strongly depending on Fermi energy. Some
discrepancies between our theoretical results and current experimental
observations are discussed.Comment: 12 pages, appendices added. Accepted for publication in Physical
Review B (submitted, October 2009
An Energy Sharing Game with Generalized Demand Bidding: Model and Properties
This paper proposes a novel energy sharing mechanism for prosumers who can
produce and consume. Different from most existing works, the role of individual
prosumer as a seller or buyer in our model is endogenously determined. Several
desirable properties of the proposed mechanism are proved based on a
generalized game-theoretic model. We show that the Nash equilibrium exists and
is the unique solution of an equivalent convex optimization problem. The
sharing price at the Nash equilibrium equals to the average marginal disutility
of all prosumers. We also prove that every prosumer has the incentive to
participate in the sharing market, and prosumers' total cost decreases with
increasing absolute value of price sensitivity. Furthermore, the Nash
equilibrium approaches the social optimal as the number of prosumers grows, and
competition can improve social welfare.Comment: 16 pages, 7 figure
Empirical properties of inter-cancellation durations in the Chinese stock market
Order cancellation process plays a crucial role in the dynamics of price
formation in order-driven stock markets and is important in the construction
and validation of computational finance models. Based on the order flow data of
18 liquid stocks traded on the Shenzhen Stock Exchange in 2003, we investigate
the empirical statistical properties of inter-cancellation durations in units
of events defined as the waiting times between two consecutive cancellations.
The inter-cancellation durations for both buy and sell orders of all the stocks
favor a -exponential distribution when the maximum likelihood estimation
method is adopted; In contrast, both cancelled buy orders of 6 stocks and
cancelled sell orders of 3 stocks prefer Weibull distribution when the
nonlinear least-square estimation is used. Applying detrended fluctuation
analysis (DFA), centered detrending moving average (CDMA) and multifractal
detrended fluctuation analysis (MF-DFA) methods, we unveil that the
inter-cancellation duration time series process long memory and multifractal
nature for both buy and sell cancellations of all the stocks. Our findings show
that order cancellation processes exhibit long-range correlated bursty
behaviors and are thus not Poissonian.Comment: 14 pages, 7 figures and 5 table
Does engaging in government initiated corporate social responsibility activities improve corporate innovation? Evidence from China
The Chinese government initiated a nationwide poverty alleviation
campaign in 2016. Many Chinese listed firms engaged in
poverty alleviation campaign and made significant contributions.
In this study, we investigate the relationship between firms’ poverty
alleviation campaign and firm innovation performance. Using
a large sample of 3140 Chinese A-share listed firms on Shenzhen
and Shanghai Stock Exchange from 2016 to 2019, this study demonstrates
that firms’ poverty alleviation campaign contribute to
the improvement of firm innovation performance. These results
are more pronounced for firms with higher internet search volume.
Overall, our findings provide important support for listed
firms to engage in CSR activities initiated by governmen
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