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991.
This study examines the reasons underlying gender swapping and its impacts on online gaming behavior. While previous studies considered gender swapping to be an abnormal or rare exception in one's self‐presentation, this study hypothesized that people swap genders as a rational choice based on practical benefits. An online survey was conducted with 318 male players of MMORPGs in Korea. Players swapped gender in games to gain benefits from other players under the condition of anonymity rather than to represent their own gender identity. Men playing female avatars displayed more socially amiable behaviors conventionally characterized as more feminine. Moreover, players were more willing to purchase virtual goods to decorate their gender swapped avatars, mediated by their emotional attachment to their avatar. 相似文献
992.
B-spline curve extension is an important operation in computer aided design systems. In this paper, we present a new extension algorithm for B-spline curves. The algorithm uses curve unclamping to generate a uniform B-spline curve segment from the original curve and gradually extends the segment to pass through every target point. Algorithms of uniform B-spline curves are used such that our algorithm has a low time cost and can easily handle arbitrary-order derivative constraints at the target points. Generalization for non-uniform rational B-spline curve extension is also discussed, and examples show the efficiency of our method. 相似文献
993.
Most automatic steering systems for large tractors are designed with hydraulic systems that run on either constant flow or constant pressure. Such designs are limited in adaptability and applicability. Moreover, their control valves can unload in the neutral position and eventually lead to serious hydraulic leakage over long operation periods. In response to the problems noted above, a multifunctional automatic hydraulic steering circuit is presented. The system design is composed of a 5-way-3- position proportional directional valve, two pilot-controlled check valves, a pressure-compensated directional valve, a pressurecompensated flow regulator valve, a load shuttle valve, and a check valve, among other components. It is adaptable to most open-center systems with constant flow supply and closed-center systems with load feedback. The design maintains the lowest pressure under load feedback and stays at the neutral position during unloading, thus meeting the requirements for steering. The steering controller is based on proportional-integral-derivative (PID) running on a 51-microcontroller-unit master control chip. An experimental platform is developed to establish the basic characteristics of the system subject to stepwise inputs and sinusoidal tracking. Test results show that the system design demonstrates excellent control accuracy, fast response, and negligible leak during long operation periods. 相似文献
994.
A <Emphasis Type="Italic">K</Emphasis> self-adaptive SDN controller placement for wide area networks
As a novel architecture, software-defined networking (SDN) is viewed as the key technology of future networking. The core idea of SDN is to decouple the control plane and the data plane, enabling centralized, flexible, and programmable network control. Although local area networks like data center networks have benefited from SDN, it is still a problem to deploy SDN in wide area networks (WANs) or large-scale networks. Existing works show that multiple controllers are required in WANs with each covering one small SDN domain. However, the problems of SDN domain partition and controller placement should be further addressed. Therefore, we propose the spectral clustering based partition and placement algorithms, by which we can partition a large network into several small SDN domains efficiently and effectively. In our algorithms, the matrix perturbation theory and eigengap are used to discover the stability of SDN domains and decide the optimal number of SDN domains automatically. To evaluate our algorithms, we develop a new experimental framework with the Internet2 topology and other available WAN topologies. The results show the effectiveness of our algorithm for the SDN domain partition and controller placement problems. 相似文献
995.
能够无创定量测量人体组织弹性模量的声辐射力脉冲超声弹性成像方法,已经逐渐成为进行肝硬化分期和乳腺癌良恶性判别等临床诊断的重要工具。但是,在临床实践中也发现,弹性模量测量的稳定性会受到测量深度和组织各向异性等多种因素的影响。因此,如何通过算法的改进提高声辐射力脉冲超声弹性成像测量结果的可靠性,一直是该领域所关注的重要课题之一。文章对现有的基于拉东变换的剪切波速度估计算法进行了多种方式的改进,并利用自主研发的声辐射力定量超声弹性成像系统所采集的超声射频数据,对几种方法得出的剪切波速度测量结果进行了比较。这些改进算法可以被分为两类:(I)在以“时间-侧向位置”为坐标的位移矩阵上进行拉东变换;(II)在以“时间-深度”为坐标的位移矩阵上进拉东变换。第一类算法试图找到在某一个特定深度上剪切波侧向传播的最佳拟合轨迹,而第二类算法则试图直接找到在整个测量深度范围内,剪切波波前通过每个侧向位置的准确时间点。文章在标准弹性仿体和离体猪肉组织样本上进行了测量实验,比较了在不同深度位置上重复测量结果的可靠性,以及这些算法的耗时情况。实验结果将有助于我们找到一种兼顾测量稳定性和计算速度的新型剪切波速度估计算法,并将其应用到声辐射力脉冲超声弹性成像中,提高其测量结果的可靠性和在临床应用中的价值。 相似文献
996.
997.
998.
A Maximum Principle via Malliavin calculus for combined stochastic control and impulse control of forward‐backward systems 下载免费PDF全文
We consider a combined stochastic control and impulse control problem of forward‐backward systems driven by Lévy processes, where both the system coefficients and the objective performance functional are allowed to be random, non‐Markovian; the information available to the controller is partial information. Applying a Malliavin calculus approach, we derive a maximum principle for this control problem, where the adjoint processes are explicitly represented by the parameters and the states of the system. Finally, we give two examples of applications. © 2015 Chinese Automatic Control Society and Wiley Publishing Asia Pty Ltd 相似文献
999.
In this paper, by introducing a function with nonlinear gains and developing sliding surfaces with integral action in the dynamic surface control (DSC) recursive procedure, a novel DSC strategy is proposed. The drawbacks of conventional DSC methods, such as being sensitive to the design constant of the first order low‐pass filter and being unable to achieve zero steady‐state error for step reference signal, are overcome. Moreover, improvement of transient performance and reduction of control effort can be obtained. The stability analysis shows that the proposed new approach can guarantee semi‐global uniform ultimate boundedness (SGUUB) of all closed‐loop signals and that the ultimate tracking error bound in regulation can be made arbitrarily small. 相似文献
1000.
硫熏强度是亚法糖厂澄清工段的关键工艺参数之一;硫熏强度过低会影响澄清效果,过高会造成成品糖二氧化硫残留过高;目前由于缺乏合适的硫熏强度在线测量装置,该参数主要采用人工取样和离线化验的检测方式,化验滞后时间较长,难以根据该指标及时指导实际生产的问题;为此文章采用极限学习机(ELLM)方法建立了硫熏强度软测量模型,并与基于支持向量机(SVM)、径向基函数(RBF)神经网络和反向传播(BP)神经网络的硫熏强度软测量模型进行对比分析;结果显示,基于ELM的硫熏强度软测量模型具有训练收敛速度快、模型精度高和泛化性能好等优点,可以满足实际糖厂澄清工段的要求. 相似文献