刍议郑州市引黄工程的误区与对策

黄河水资源是郑州市发展的基础资源,但郑州市近些年来在黄河水资源的利用方面没有统一规划与管理,致使引黄水利工程重复建设、水利工程盲目开建停建、引黄设备闲置等现象存在,在水资源水量分配方面也与郑州市的发展不相适应。针对诸多问题,本文提出了个人的见解及解决问题的对策。     

国际放射防护委员会所用的组织权重因子的演变

本文阐述国际放射防护委员会所采用辐射致部危险度和组织权重因子的改变。着重介绍ＩＣＲＰ１９９０年建议书中有关辐射危害的估算方法，在总危害中不仅考虑到辐射诱发致死癌症的概率，还考虑辐射诱发非致死癌症的概率，在受照者所有后代产生的严重遗传疾患的概率，以及这些有害作用所致的预期寿命损失。     

关于复合水气交替注入（WAG）驱油中粘性指进的预测模型

本文运用不可调参数建立了一个关于复合水气交替注入驱油中粘性指进问题的预测模型。利用该模型可生成一个可应用在常规复合模拟程序中的拟函数，且已成功地运用在三种类型实例中，包括一个简单的非均质油藏。     

山西省高校知识竞争力指数的测度与评价

对区域知识竞争力指数的测度与评价是衡量一个区域知识竞争力优劣的有效方法。本文从知识竞争力的角度,运用管理统计软件SPSS及SWOT分析法,对2010年度山西省14所高校的知识竞争力指数进行了总排名及关键要素排名,并做了总体评价,提出提升山西高校知识竞争力的总体策略。     

Distributed Proportional-spatial Derivative control of nonlinear parabolic systems via fuzzy PDE modeling approach

In this paper, a distributed fuzzy control design based on Proportional-spatial Derivative (P-sD) is proposed for the exponential stabilization of a class of nonlinear spatially distributed systems described by parabolic partial differential equations (PDEs). Initially, a Takagi-Sugeno (T-S) fuzzy parabolic PDE model is proposed to accurately represent the nonlinear parabolic PDE system. Then, based on the T-S fuzzy PDE model, a novel distributed fuzzy P-sD state feedback controller is developed by combining the PDE theory and the Lyapunov technique, such that the closed-loop PDE system is exponentially stable with a given decay rate. The sufficient condition on the existence of an exponentially stabilizing fuzzy controller is given in terms of a set of spatial differential linear matrix inequalities (SDLMIs). A recursive algorithm based on the finite-difference approximation and the linear matrix inequality (LMI) techniques is also provided to solve these SDLMIs. Finally, the developed design methodology is successfully applied to the feedback control of the Fitz-Hugh-Nagumo equation.     

The right view from the wrong location: depth perception in stereoscopic multi-user virtual environments

Stereoscopic depth cues improve depth perception and increase immersion within virtual environments (VEs). However, improper display of these cues can distort perceived distances and directions. Consider a multi-user VE, where all users view identical stereoscopic images regardless of physical location. In this scenario, cues are typically customized for one "leader" equipped with a head-tracking device. This user stands at the center of projection (CoP) and all other users ("followers") view the scene from other locations and receive improper depth cues. This paper examines perceived depth distortion when viewing stereoscopic VEs from follower perspectives and the impact of these distortions on collaborative spatial judgments. Pairs of participants made collaborative depth judgments of virtual shapes viewed from the CoP or after displacement forward or backward. Forward and backward displacement caused perceived depth compression and expansion, respectively, with greater compression than expansion. Furthermore, distortion was less than predicted by a ray-intersection model of stereo geometry. Collaboration times were significantly longer when participants stood at different locations compared to the same location, and increased with greater perceived depth discrepancy between the two viewing locations. These findings advance our understanding of spatial distortions in multi-user VEs, and suggest a strategy for reducing distortion.