Distinguishing addiction and high engagement in the context of online game playing

This study considered whether the distinction between core and peripheral criteria for behavioral addiction, previously drawn with respect to computing activities in general, applies in the specific area of Massively Multiplayer Online Game playing. Questionnaire items were administered over the Internet to 442 game players. Factor-analysis of the data supported the previous findings for computing in general. An addiction factor loaded on items tapping previously identified core criteria (conflict, withdrawal symptoms, relapse and reinstatement and behavioral salience) and a (non-pathological) engagement factor loaded on items tapping previously identified peripheral criteria (cognitive salience, tolerance and euphoria). Analysis of response frequencies supported the existence of a developmental process whereby peripheral criteria are met before core criteria. Players who might be considered addicted using a monothetic classification system involving only the core criteria were shown to spend a significantly greater amount of time playing per week than those endorsing only the peripheral criteria. It is concluded that the study supports the idea that it is inappropriate to use some of the previously used criteria for addiction when researching or diagnosing computer-related addictions. Implications of the present findings for Internet-mediated data collection methodologies are also discussed.     

PAM-TH-UWB系统抗UMTS干扰性能分析

分析了UMTS／WCDMA系统所产生的干扰对PAM—IR-UWB系统的影响，推导出了UWB系统在存在UMTS干扰下的误比特率公式，解析分析了UWB发射信号的基本参数与抗UMTS干扰能力之间的关系。数值计算和仿真验证了分析的正确性和UWB系统抗UMTS干扰的能力。     

形成三星星座的最优脉冲变轨的控制与仿真

由于火箭发射入轨精度的限制,无法直接发射形成星座,星座的形成需要变轨。该文针对三星星座,进行星座发射中的最优脉冲式变轨研究,文中基于卫星相对运动状态转移方程,推出了星座双脉冲式变轨控制的理论解;利用遗传算法,对双脉冲式变轨的脉冲控制量进行了优化仿真;探讨了星座脉冲式变轨的工程实现途径,为工程应用和研究提供参考。     

单级齿轮箱内部冲击振动的传播衰减特性研究

齿轮箱箱体表面的振动信号包含了丰富的内部状态信息,因此成为系统动态特性辨识和结构故障诊断的主要依据。考虑到啮合刚度,以及加工误差或齿面缺陷的激励作用,从内部激励源到表面拾振点之间形成了多级、多界面的振动传递过程,沿不同路径的传播、衰减特性直接决定了振动信号采集的质量。建立某单级齿轮箱的有限元模型,通过模态叠加法完成了该结构的冲击响应分析,研究了沿不同传播路径的界面传播与衰减情况,并通过振动幅值能量和能量传播损耗率两个参数实现了衰减特性的定量分析。最终通过齿轮箱试验台的脉冲响应试验,验证了数值仿真的准确性,并建立了可信的齿轮箱冲击振动衰减规律。     

Theoretical Investigation of Some High‐Performance Novel Amine Azide Propellants

Monomethylhydrazine (MMH) is currently the most widely used hypergolic propellant, due to its high performance and low ignition delay. However, its toxicity is a major concern. The present work aims at developing high‐performance hypergolic fuels that are based on tertiary amine azide functionality. A number of potential amine azide candidates have been proposed, and some of their physical and chemical properties have been computed using state‐of‐the‐art molecular modeling techniques. Gas‐phase heats of formation have been calculated using the CBS‐QB3 method, and the first‐principle COSMO‐RS method has been used to compute heats of vaporization and vapor pressures. A density correlation, based on molecular‐volume calculation, has been established to predict the densities of the candidate molecules. Finally, the liquid‐phase heats of formation and densities have been used to predict the specific and density impulses of the proposed candidate molecules. The results show that many of the molecules proposed here have much higher density impulse than that of MMH, and may be considered for experimental studies.     

Flicker visibility and related visual discomfort in 3‐D displays with LED backlight

Abstract— In this paper, the perception of flicker in time‐sequential or field‐sequential 3‐D LC TVs driven by LED backlights is described. The seriousness of the perceived flicker and its influence on visual discomfort is investigated for various backlight operational modes. Results show that display backlights presenting different temporal light distribution have significant contribution to flicker visibility and visual discomfort. The display dimension, 2‐D or 3‐D, affects visual discomfort but not flicker visibility. The relationship between visual discomfort and flicker visibility is proportional when rendering 2‐D images, but not in the case of 3‐D images. Finally, a simple model is presented to evaluate visual discomfort related to flicker in 2‐D rendering.     

基于粒子群算法的图像椒盐噪声去除算法

针对图像中的椒盐噪声消除问题,提出了一种基于粒子群算法的自适应开关中值滤波算法。提出的滤波器算法主要由两大阶段组成:噪声检测阶段和噪声滤除阶段。与标准中值滤波相比,提出的自适应开关中值滤波算法能够生成污染图像的噪波图。通过噪波图可以得到图像的污染和未污染像素信息。在滤除过程中,滤波器计算出未污染相邻像素的中值并且替换污染像素。仿真实验结果证实了所提算法的有效性,其能够有效地提高图像的峰值信噪比和图像质量;相比现有其他方法,所提算法的去噪效果更好。     

Young’s modulus evolution during heating,re-sintering and cooling of partially sintered alumina ceramics

The Young modulus of partially and fully sintered alumina ceramics, obtained by firing to different temperatures (range 1200–1600°C), has been determined via impulse excitation, and the evolution of Young’s modulus of partially sintered alumina with temperature has been monitored from room temperature to 1600°C. As expected, the room-temperature Young modulus of the partially sintered materials is lower than all theoretical predictions. With increasing temperature Young’s modulus decreases, until the original firing temperature is exceeded and sintering (densification) continues, resulting in a steep Young’s modulus increase. During heating and cooling the temperature dependence obeys a master curve for alumina, unless the temperature of the original firing is excessively low.     

模型预测算法在温度控制中的应用

介绍一种控制算法及在温度控制中的应用，它用系统的脉冲响应建立“预测模型”，这样的模型包含了关于系统动态的主要信息．温度过程的脉冲响应容易在线测取，故而省去了费力很大的“建模”工作．现场整定参数只有一个，使用方便，该算法仿真和试用结果令人满意     

A new approach on vibration analysis of locally nonlinear stiffness and damping system

The nonlinear force induced by spring and damping of 2-degree-of-freedom locally nonlinear vibrating system is regarded as applied force, and its mathematical model is established in this paper. Then impulse response temporal method of linear vibrating system is applied in the system, the response of locally nonlinear vibrating system is obtained by convolution integration between unit impulse response of corresponding linear system and equivalent nonlinear force, and numerical simulation of the model is attained. Finally, the feasibility of the new method on the domain of locally nonlinear vibrating system is verified by comparing the results, which supplies a new method to solve approximately vibration response of locally nonlinear vibrating systems.