Line Integral Convolution for Real‐Time Illustration of Molecular Surface Shape and Salient Regions

We present a novel line drawing algorithm that illustrates surfaces in real‐time to convey their shape. We use line integral convolution (LIC) and employ ambient occlusion for illustrative surface rendering. Furthermore, our method depicts salient regions based on the illumination gradient. Our method works on animated surfaces in a frame‐coherent manner. Therefore, it yields an illustrative representation of time‐dependent surfaces as no preprocessing step is needed. In this paper, the method is used to highlight the structure of molecular surfaces and to illustrate important surface features like cavities, channels, and pockets. The benefit of our method was evaluated with domain experts. We also demonstrate the applicability of our method to medical visualization.     

Adaptive Surface Visualization of Vessels with Animated Blood Flow

The investigation of hemodynamic information for the assessment of cardiovascular diseases (CVDs) gained importance in recent years. Improved flow measuring modalities and computational fluid dynamics (CFD) simulations yield in reliable blood flow information. For a visual exploration of the flow information, domain experts are used to investigate the flow information combined with its enclosed vessel anatomy. Since the flow is spatially embedded in the surrounding vessel surface, occlusion problems have to be resolved. A visual reduction of the vessel surface that still provides important anatomical features is required. We accomplish this by applying an adaptive surface visualization inspired by the suggestive contour measure. Furthermore, an illustration is employed to highlight the animated pathlines and to emphasize nearby surface regions. Our approach combines several visualization techniques to improve the perception of surface shape and depth. Thereby, we ensure appropriate visibility of the embedded flow information, which can be depicted with established or advanced flow visualization techniques. We apply our approach to cerebral aneurysms and aortas with simulated and measured blood flow. An informal user feedback with nine domain experts, we confirm the advantages of our approach compared with existing methods, e.g. semi‐transparent surface rendering. Additionally, we assessed the applicability and usefulness of the pathline animation with highlighting nearby surface regions.     

Adaptive texture space shading for stochastic rendering

When rendering effects such as motion blur and defocus blur, shading can become very expensive if done in a naïve way, i.e. shading each visibility sample. To improve performance, previous work often decouple shading from visibility sampling using shader caching algorithms. We present a novel technique for reusing shading in a stochastic rasterizer. Shading is computed hierarchically and sparsely in an object‐space texture, and by selecting an appropriate mipmap level for each triangle, we ensure that the shading rate is sufficiently high so that no noticeable blurring is introduced in the rendered image. Furthermore, with a two‐pass algorithm, we separate shading from reuse and thus avoid GPU thread synchronization. Our method runs at real‐time frame rates and is up to 3 × faster than previous methods. This is an important step forward for stochastic rasterization in real time.     

Error analysis of estimators that use combinations of stochastic sampling strategies for direct illumination

We present a theoretical analysis of error of combinations of Monte Carlo estimators used in image synthesis. Importance sampling and multiple importance sampling are popular variance‐reduction strategies. Unfortunately, neither strategy improves the rate of convergence of Monte Carlo integration. Jittered sampling (a type of stratified sampling), on the other hand is known to improve the convergence rate. Most rendering software optimistically combine importance sampling with jittered sampling, hoping to achieve both. We derive the exact error of the combination of multiple importance sampling with jittered sampling. In addition, we demonstrate a further benefit of introducing negative correlations (antithetic sampling) between estimates to the convergence rate. As with importance sampling, antithetic sampling is known to reduce error for certain classes of integrands without affecting the convergence rate. In this paper, our analysis and experiments reveal that importance and antithetic sampling, if used judiciously and in conjunction with jittered sampling, may improve convergence rates. We show the impact of such combinations of strategies on the convergence rate of estimators for direct illumination.     

Low Rank Parity Check Codes and their application in Power Line Communications smart grid networks

We investigate the use of Low Rank Parity Check Codes, originally designed for cryptography applications in the context of Power Line Communication. Particularly, we propose a new code design and an efficient probabilistic decoding algorithm. The main idea of decoding Low Rank Parity Check Codes is based on calculations of vector spaces over a finite field . Low Rank Parity Check Codes can be seen as the identical of Low Density Parity check codes. We compare the performance of this code against the Reed‐Solomon Code through a Power Line Communication channel.     

Performance of terahertz channel with multiple input multiple output techniques

Terahertz (THz) communication is being considered as a potential solution to mitigate the demand for high bandwidth. The characteristic of THz band is relatively different from present wireless channel and imposes technical challenges in the design and development of communication systems. Due to the high path loss in THz band, wireless THz communication can be used for relatively short distances. Even, for a distance of few meters (>5m), the absorption coefficient is very high and hence the performance of the system is poor. The use of multiple antennas for wireless communication systems has gained overwhelming interest during the last two decades. Multiple Input Multiple Output (MIMO) Spatial diversity technique has been exploited in this paper to improve the performance in terahertz band. The results show that the Bit Error Rate (BER) is considerably improved for short distance (<5m) with MIMO. However, as the distance increases, the improvement in the error performance is not significant even with increase in the order of diversity. This is because, as distance increases, in some frequency bands the signal gets absorbed by water vapor and results in poor transmission. Adaptive modulation scheme is implemented to avoid these error prone frequencies. Adaptive modulation with receiver diversity is proposed in this work and has improved the BER performance of the channel for distance greater than 5m.     

UPS设计新概念在线互动式与传统在线式设计比较

人们普遍认为UPS技术只有后备式和在线式两种,面对UPS技术第三代-在线互动式,人们缺乏充分的认识。本文对在线互动式与传统在线式进行了比较和分析。     

用微机绘制一元线性回归的拟合直线(之二)(绘制金属电阻～温度关系曲线)

介绍TurboC编程序,在《用双臂电桥（Kelvinbridge）测量低电阻》的实验中根据测定一段铜丝用在不同温度时的一组低电阻值,用最小二乘法实现直线拟舍,求得铜的电阻温度系数和这一段铜丝在0℃时的电阻值,并绘制出金属电阻～温度R（t）（Ω）～t（℃））关系曲线     

用遗传算法辅助设计的人工神经网络计算配电网线损

利用遗传算法（ＧＡ）辅助设计的人工神经网络（ＡＮＮ）进行配电网线损计算。首先通过ＧＡ来确定ＡＮＮ的三个参数（隐含层中神经元个数、学习速率和动量因子）,然后应用ＢＰ型神经网络来拟合影响线损的特征参数与线损之间的复杂关系,在此基础上提出了计算配网线损的简单、准确而实用的方法。实例计算结果表明,该算法比现有其它计算配网线损的方法更为准确。     

树型分支电网单相断线兼接地故障特征

当树型分支电网的某一点发生断线兼线地短路时,在只限于起端电压,电流可测的条件下,故障诊断的关键是区分真、伪故障点。