Aligning principal and agent’s incentives: A principal–agent perspective of social networking sites

The viability of networked communities depends on the creation and disclosure of user-generated content and the frequency of user visitation (Facebook 10-K Annual Report, 2012). However, little is known about how to align the interests of user and social networking sites. In this study, we draw upon the principal-agent perspective to extend Pavlou et al.’s uncertainty mitigation model of online exchange relationships (2007) and propose an empirically tested model for aligning the incentives of the principal (user) and the agent (service provider). As suggested by Pavlou et al., we incorporated a multi-dimensional measure of trust: trust of provider and trust of members. The proposed model is empirically tested with survey data from 305 adults aged 20-55. The results support our model, delineating how real individuals with bounded rationality actually make decision about information disclosure under uncertainty in the social networking site context. There is show little to no relationship between online privacy concerns and information disclosure on online social network sites. Perceived benefits provide the linkage between the incentives of principal (user) and agent (provider) while usage intensity demonstrated the most significant impact on information disclosure. We argue that the phenomenon may be explained through Communication Privacy Management Theory. The present study enhances our understanding of agency theory and human judgment theory in the context of social media. Practical implications for understanding and facilitating online social exchange relationships are also discussed.     

电化学界面处离子分布、静电势和ξ势的研究

Density functional theory is applied to predicting the structures and electrostatic potentials of planar electrochemical surfaces within the framework of the restricted primitive model where small ions are represented by charged hard spheres of equal diameter and the solvent is assumed to be a continuous dielectric medium. The hard-sphere contribution to the excess Helmholtz energy functional is evaluated using the modified fundamentalmeasure theory and the electrostatic contribution is obtained from the quadratic functional Taylor expansion using the second-order direct correlation function from the mean-spherical approximation. Numerical results for the ionic density profiles and the mean electrostatic potentials near a planar surface of various charge densities are in excellent agreement with molecular simulations. In contrast to the modified Gouy-Chapman theory, the present density functional theory correctly predicts the second layer formation and charge inversion of charged surfaces as observed in simulations and in experiments. The theory has also been tested with the zeta potentials of positively charged polystyrene particles in aqueous solutions of KBr. Good agreement is achieved between the calculated and experimental results.     

螺旋槽管外含高浓度不凝组分蒸汽冷凝传热研究

分析了含高浓度不凝组分蒸汽在立式螺旋槽管表面强制对流冷凝的传热机理。在不凝性组分体积百分浓度超过９０％时，螺旋槽管的强化传热效果不明显，而含量为４４％～９０％时，螺旋槽管总换热系数比光滑管提高２０％～３５％。     

A unified model for the structure of polymers in semidilute solution

A model is developed to analyse the concentration dependence of the range ξ_? of the monomer pair correlation function. In semidilute solution, three concentration regimes are found for semiflexible molecules and the crossover points between the various regimes are predicted in terms of the characteristic ratio of the chains in dilute solution and in terms of the Flory interaction parameter χ. A simple physical interpretation is given which explains the concentration dependence of ξ_? based on binary contacts initially and then ternary contacts at higher concentration. Temperature-concentration diagrams are developed for several common polymer-solvent systems.     

声纹认证前端音频预处理SOPC设计

针对声纹身份认证一体化设计需求,基于SystemVue和Quartus Ⅱ平台,利用DSP Builder技术,在EP2C35F芯片上完成了用于声纹特征提取的前端音频预处理模块的SOPC设计。主要通过SystemVue设计数字音频滤波器参数,然后结合Simulink平台完成基于线性相位结构和分布式(DA)算法的低通滤波器结构设计,最后通过Signal Compiler转换为HDL语言完成设计。实验结果表明,系统可以有效限制音频信号的带宽,减少带外噪声;利用DSP Builder设计具有线性相位结构和DA算法的滤波器,设计周期短,占用逻辑资源少,其运算速度有很大提高;MATLAB理论计算也验证了设计的正确性。     

基于全散度的C-V模型阈值法

为了提高传统C-V模型的收敛速度并降低其对噪声的敏感性,提出基于全散度的C-V模型及其快速阈值分割算法。将Bregman散度与全散度统一获得新的全散度,并将其引入C-V模型的拟合偏差项,提高图像灰度值与分割区域平均灰度偏差值计算的鲁棒性。同时,采用变分水平集理论获得基于直方图的快速阈值计算方法。实验结果表明,该方法分割效果及收敛速度得到提高,且具有较好的鲁棒性和抗噪性。     

蔗渣浆低浓黑液多聚物粘度对温度依赖性的关联模型

利用聚合物自由体积理论模拟了蔗渣浆低浓黑液对粘度对温度的依赖性的数学模型，最终得出黑液多聚物粘度与温度的相关式：η=A1exp[B1/(T-T0)]。利用示差扫描量热分析技术（DSC）得出了蔗渣黑液多聚物中连续相与分散相的转变曲线，并获得了表观温度T0的平均值为255K；通过实验数据拟合可回归出蔗渣黑液多聚物在不同浓度时的系数A1和B1值。因此，使用该粘度的数学模型可估算蔗渣低浓（接近40％固含量）黑液多聚物在操作温度范围内（20－100℃）的粘度值。     

Novel multi-objective resource allocation and activity scheduling for fourth party logistics

In order to reduce logistic costs, the scheduling of logistic tasks and resources for fourth party logistics (4PL) is studied. Current scheduling models only consider costs and finish times of each logistic resource or task. Not generally considered are the joint cost and time between two adjacent activities for a resource to process and two sequential activities of a task for two different resources to process are ignored. Therefore, a multi-objective scheduling model aiming at minimizing total operation costs, finishing time and tardiness of all logistic tasks in a 4PL is proposed. Not only are the joint cost and time of logistic activities between two adjacent activities and two sequential activities included but the constraints of resource time windows and due date of tasks are also considered. An improved nondominated sorting genetic algorithm (NSGA-II) is presented to solve the model. The validity of the proposed model and algorithm are verified by a corresponding case study.