143 research outputs found

    A Strategy Optimization Approach for Mission Deployment in Distributed Systems

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    In order to increase operational efficiency, reduce delays, and/or maximize profit, almost all the organizations have split their mission into several tasks which are deployed in distributed system. However, due to distributivity, the mission is prone to be vulnerable to kinds of cyberattacks. In this paper, we propose a mission deployment scheme to optimize mission payoff in the face of different attack strategies. Using this scheme, defenders can achieve “appropriate security” and force attackers to jointly safeguard the mission situation

    Understanding Satisfaction of Knowledge Contributors in Transactional Virtual Communities from A Cost-Benefit Tradeoff Perspective

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    Knowledge sharing behavior in virtual communities has long been an important area of research. Prior related research has primarily focused on relational virtual community (RVC) where knowledge sharing is regarded as a social exchange behavior, heavily depending on the social concerns such as reciprocity, identification and norms. The objective of our study is to investigate knowledge contributors’ satisfaction in a distinct type of virtual communities (transactional virtual communities, TVCs), where knowledge sharing is mainly guided under the principle of economic exchange, and cost-benefit tradeoff is the primary motives for knowledge sharing. Drawing upon the goal attainment theory, we examine the effects of two types of benefits (e.g., extrinsic and intrinsic benefit) and two types of costs (e.g., actual and opportunity cost) on knowledge contributors’ satisfaction, as well as the mediating role of perceived net goal attainment. A field survey with 205 subjects in a specific TVC in China was conducted to test the research model. We find that knowledge contributors’ perceptions of extrinsic and intrinsic benefits and opportunity cost significantly influence their satisfaction through the full mediation of perceived net goal attainment. Implications and future research are discussed

    Determination of the Form Factors for the Decay B0 --> D*-l+nu_l and of the CKM Matrix Element |Vcb|

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    We present a combined measurement of the Cabibbo-Kobayashi-Maskawa matrix element Vcb|V_{cb}| and of the parameters ρ2\rho^2, R1R_1, and R2R_2, which fully characterize the form factors of the B0D+νB^0 \to D^{*-}\ell^{+}\nu_\ell decay in the framework of HQET, based on a sample of about 52,800 B0D+νB^0 \to D^{*-}\ell^{+}\nu_\ell decays recorded by the BABAR detector. The kinematical information of the fully reconstructed decay is used to extract the following values for the parameters (where the first errors are statistical and the second systematic): ρ2=1.156±0.094±0.028\rho^2 = 1.156 \pm 0.094 \pm 0.028, R1=1.329±0.131±0.044R_1 = 1.329 \pm 0.131 \pm 0.044, R2=0.859±0.077±0.022R_2 = 0.859 \pm 0.077 \pm 0.022, F(1)Vcb=(35.03±0.39±1.15)×103\mathcal{F}(1)|V_{cb}| = (35.03 \pm 0.39 \pm 1.15) \times 10^{-3}. By combining these measurements with the previous BABAR measurements of the form factors which employs a different technique on a partial sample of the data, we improve the statistical accuracy of the measurement, obtaining: ρ2=1.179±0.048±0.028,R1=1.417±0.061±0.044,R2=0.836±0.037±0.022,\rho^2 = 1.179 \pm 0.048 \pm 0.028, R_1 = 1.417 \pm 0.061 \pm 0.044, R_2 = 0.836 \pm 0.037 \pm 0.022, and F(1)Vcb=(34.68±0.32±1.15)×103. \mathcal{F}(1)|V_{cb}| = (34.68 \pm 0.32 \pm 1.15) \times 10^{-3}. Using the lattice calculations for the axial form factor F(1)\mathcal{F}(1), we extract Vcb=(37.74±0.35±1.25±1.441.23)×103|V_{cb}| =(37.74 \pm 0.35 \pm 1.25 \pm ^{1.23}_{1.44}) \times 10^{-3}, where the third error is due to the uncertainty in F(1)\mathcal{F}(1)

    Study of the Exclusive Initial-State Radiation Production of the DDˉD \bar D System

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    A study of exclusive production of the DDˉD \bar D system through initial-state r adiation is performed in a search for charmonium states, where D=D0D=D^0 or D+D^+. The D0D^0 mesons are reconstructed in the D0Kπ+D^0 \to K^- \pi^+, D0Kπ+π0D^0 \to K^- \pi^+ \pi^0, and D0Kπ+π+πD^0 \to K^- \pi^+ \pi^+ \pi^- decay modes. The D+D^+ is reconstructed through the D+Kπ+π+D^+ \to K^- \pi^+ \pi^+ decay mode. The analysis makes use of an integrated luminosity of 288.5 fb1^{-1} collected by the BaBar experiment. The DDˉD \bar D mass spectrum shows a clear ψ(3770)\psi(3770) signal. Further structures appear in the 3.9 and 4.1 GeV/c2c^2 regions. No evidence is found for Y(4260) decays to DDˉD \bar D, implying an up per limit \frac{\BR(Y(4260)\to D \bar D)}{\BR(Y(4260)\to J/\psi \pi^+ \pi^-)} < 7.6 (95 % confidence level)

    Optimal Tradable Credit Scheme Design with Recommended Credit Price

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    As an interesting research topic in transportation field, tradable credit scheme (TCS) has been extensively explored in the latest decade. Existing studies implicitly assumed that travelers are clear about the equilibrium credit price and make their trips accordingly. However, this may not be the case in reality, since the credit price is endogenously determined by the credit-trading behavior, especially in the early stages after the implementation of a TCS. Considering travelers’ uncertainty on the equilibrium credit price, this paper aims to investigate the impacts of perception error on credit price and how to accommodate such errors by an appropriate scheme design. Transferring the perception error on credit price to a given and fixed value released by central authority, we first investigate the impacts of recommended credit price under a given TCS. The numerical results imply that it is necessary to simultaneously consider the choice of recommended credit price and charging scheme in TCS design. Regarding this, we combine the goals of social welfare and public acceptance of the scheme and propose a bilevel biobjective programming (BLBOP) model, by which the net economic benefit is maximized while the gap between the recommended and realized credit prices is minimized. Through two numerical examples, it is found that the rise in perception variance could intensify the contradiction effect between the two objectives. Additionally, a nonnegligible price gap must be allowed to occur to maintain the effectiveness of a TCS
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