Weighted average indoor positioning algorithm that uses LEDs and image sensors

We propose a weighted average indoor positioning algorithm, which is an improved version of the M.S. Rahman’s algorithm, for the calculation of unknown positions in a visible light communication system consisting of light-emitting diodes (LEDs) and image sensors. The algorithm considers the LED illumination intensity as a key factor, and the generalized Lambert illumination model is adopted to estimate the LED illumination intensity of each pixel in the images obtained at the sensors. The LED illumination intensity is normalized as a weighting factor, following the determination of the center position of the LED image. Simulations showed that the average signal-to-noise ratio in our positioning system was 19.3 dB. The simulation results also showed that the root mean square positioning error was reduced from 6.6 to 3.7 cm when the resolution of the image sensor was 3000 pixels per cm, which is comparable to the error in the widely used M.S. Rahman’s algorithm. The distance between the centers of the lenses and the focal lengths of the lenses also affects the positioning error. After the simulations, the relationship between the positioning error and the lens distance or focal length is deduced. It is observed that this algorithm has lesser positioning errors than the M.S. Rahman’s algorithm.     

Remote mobile manipulation with the centauro robot: Full‐body telepresence and autonomous operator assistance

Solving mobile manipulation tasks in inaccessible and dangerous environments is an important application of robots to support humans. Example domains are construction and maintenance of manned and unmanned stations on the moon and other planets. Suitable platforms require flexible and robust hardware, a locomotion approach that allows for navigating a wide variety of terrains, dexterous manipulation capabilities, and respective user interfaces. We present the CENTAURO system which has been designed for these requirements and consists of the Centauro robot and a set of advanced operator interfaces with complementary strength enabling the system to solve a wide range of realistic mobile manipulation tasks. The robot possesses a centaur‐like body plan and is driven by torque‐controlled compliant actuators. Four articulated legs ending in steerable wheels allow for omnidirectional driving as well as for making steps. An anthropomorphic upper body with two arms ending in five‐finger hands enables human‐like manipulation. The robot perceives its environment through a suite of multimodal sensors. The resulting platform complexity goes beyond the complexity of most known systems which puts the focus on a suitable operator interface. An operator can control the robot through a telepresence suit, which allows for flexibly solving a large variety of mobile manipulation tasks. Locomotion and manipulation functionalities on different levels of autonomy support the operation. The proposed user interfaces enable solving a wide variety of tasks without previous task‐specific training. The integrated system is evaluated in numerous teleoperated experiments that are described along with lessons learned.     

用于蓝宝石光盘的数字化数据存储

为了解决长时数据存储的难题,开展了以数字格式在蓝宝石光盘表面写入数据的研究工作。根据艾林方程,分析了利用常用无机材料进行数据存储的数据失效时间。描述了在蓝宝石材料为基底的光盘上以数字格式记录数据的基本工艺流程,重点介绍了用于蓝宝石光盘的离子束刻蚀系统。实验结果显示,蓝宝石光盘表面刻蚀的信息坑宽度为0.6μm,深度为0.2μm,磁道节距为1.6μm,符合ISO/IEC 10149:1995规定的CD-ROM格式数据存储要求,表明采用本文提出的方法实现蓝宝石光盘的数字化数据存储是可行的。此外,这种基本工艺流程不仅适用于蓝宝石光盘,同样适用于其它以高度稳定的材料(如石英玻璃)作为基底的光盘。     

Human-Specific Regulation of Neurotrophic Factors MANF and CDNF by microRNAs

Mesencephalic astrocyte derived neurotrophic factor (MANF) and cerebral dopamine neurotrophic factor (CDNF) are novel evolutionary conserved trophic factors, which exhibit cytoprotective activity via negative regulation of unfolded protein response (UPR) and inflammation. Despite multiple reports demonstrating detrimental effect of MANF/CDNF downregulation, little is known about the control of their expression. miRNAs—small non-coding RNAs—are important regulators of gene expression. Their dysregulation was demonstrated in multiple pathological processes and their ability to modulate levels of other neurotrophic factors, glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF), was previously reported. Here, for the first time we demonstrated direct regulation of MANF and CDNF by miRNAs. Using bioinformatic tools, reporter assay and analysis of endogenous MANF and CDNF, we identified that miR-144 controls MANF expression, and miR-134 and miR-141 downregulate CDNF levels. We also demonstrated that this effect is human-specific and is executed via predicted binding sites of corresponding miRNAs. Finally, we found that miR-382 suppressed hCDNF expression indirectly. In conclusion, we demonstrate for the first time direct regulation of MANF and CDNF expression by specific miRNAs, despite the fact their binding sites are not strongly evolutionary conserved. Furthermore, we demonstrate a functional effect of miR-144 mediated regulation of MANF on ER stress response markers. These findings emphasize that (1) prediction of miRNA targets based on evolutionary conservation may miss biologically meaningful regulatory pairs; and (2) interpretation of miRNA regulatory effects in animal models should be cautiously validated.     

Local anodic oxidation by atomic force microscopy for nano-Raman strain measurements on silicon-germanium thin films

Nanolithography based on local anodic oxidation (LAO) by atomic force microscopy is a promising technique for patterning strained film nanostructures on the silicon substrates. Due to its versatility and precise control, LAO is suited for preparing well defined calibration structures for local strain measurements. We investigated silicon-germanium patterns prepared by LAO and subsequent selective anisotropic wet etching. By combining the nanolithography and etching, dedicated strain test structures with a line width of 65 nm were achieved and utilized for calibration of tip-enhanced Raman measurements.     

Experimental study of the Ca–Mg–Zn system using diffusion couples and key alloys

Nine diffusion couples and 32 key samples were prepared to map the phase diagram of the Ca–Mg–Zn system. Phase relations and solubility limits were determined for binary and ternary compounds using scanning electron microscopy, electron probe microanalysis and x-ray diffraction (XRD). The crystal structure of the ternary compounds was studied by XRD and electron backscatter diffraction. Four ternary intermetallic (IM) compounds were identified in this system: Ca₃Mg_xZn_15−x (4.6 ⩽ x ⩽ 12 at 335 °C, IM1), Ca_14.5Mg_15.8Zn_69.7 (IM2), Ca₂Mg₅Zn₁₃ (IM3) and Ca_1.5Mg_55.3Zn_43.2 (IM4). Three binary compounds were found to have extended solid solubility into ternary systems: CaZn₁₁, CaZn₁₃ and Mg₂Ca form substitutional solid solutions where Mg substitutes for Zn atoms in the first two compounds, and Zn substitutes for both Ca and Mg atoms in Mg₂Ca. The isothermal section of the Ca–Mg–Zn phase diagram at 335 °C was constructed on the basis of the obtained experimental results. The morphologies of the diffusion couples in the Ca–Mg–Zn phase diagram at 335 °C were studied. Depending on the terminal compositions of the diffusion couples, the two-phase regions in the diffusion zone have either a tooth-like morphology or contain a matrix phase with isolated and/or dendritic precipitates.