Spatially constrained coordinated navigation for a multi-robot system

In this paper we present a method for navigating a multi-robot system through an environment while additionally maintaining a predefined set of constraints. Examples for constraints are the requirement to maintain a direct line-of-sight between robots or to ensure that the multi-robot system maintains communication. Our approach is based on graph structures that model movements and constraints separately, in order to cover different kind of robots and a large class of possible constraints. Additionally, the separation of movement and constraint graph allows us to use known graph algorithms like Steiner tree heuristics or the multi-point relay algorithm to solve the problem of finding a target configuration for the robots. To connect the movements of the robots with the given constraints, we introduce separated connection graphs which allow assembling valid navigation plans fast. This paper presents some theoretical insight into the problem of coordinated navigation for multi-robot systems with spatial constraints as well as a practical solution. Experiments in simulation and with real robots show the feasibility of the approach.     

End of life management of industrial robots

End of life management (EOL) is currently a hot topic in the electronics industry. Currently, mostly IT equipment and goods of consumer electronics are considered. In the nearest future automation equipment has also to be taken into account. There are three possibilities depending on the age and kind of the device: resell–reuse–recycle, called the “3Rs”. For recycling fully or semi-automated disassembly will gain in importance in the nearest future also for robots. Producers of robots have to take into account EoL because of regulations and laws as well as according to ethical codes contributing to protection of the environment. Based on previous works a real example will be presented and discussed.     

UNICORE 6 — Recent and Future Advancements

UNICORE is a European Grid Technology with more than 10 years of history. Originating from the Supercomputing domain, the latest version UNICORE 6 has turned into a general-purpose Grid technology that follows established standards and offers a rich set of features to its users. The paper starts with an architectural insight into UNICORE 6, highlighting the workflow features, standards and the different clients. Next, the current state of advancement is presented by describing recent developments. The paper closes with an outlook on future planned developments.     

0.18μm铜金属双重镶嵌工艺中空间成像套刻精度分析

由于空间成像套刻(Overlay)技术的预算随集成电路(IC)设计规范的紧缩而吃紧,因此,Overlay测量技术准确度的重要意义也随之提高。通过对后开发(AfterDevelopDI)阶段和后蚀刻(AfterEtchFI)阶段的Overlay测量结果进行比较,研究了0.18μm设计规范下的铜金属双重镶嵌工艺过程中的Overlay准确度。在确保对同一个晶圆进行后开发(DI)阶段和后蚀刻(FI)阶段测试的条件下,我们对成品晶圆的5个工艺层进行了比较。此外,还利用CD-SEM(线宽-扫描电子显微镜)测量了某个工艺层(PolyGate)上的芯片内Overlay,并与采用分割线方法的光学Overlay测量结果进行了比较。发现对芯片内overlay的校准存在着严重的局限性,即在应用CD-SEM时缺乏合适的结构进行Overlay测量。我们还将继续为大家提供定量的比较结果,同时也会向大家推荐组合的CD-SEM测量结构,使其能够被应用到今后的光刻设计中。     

Composite Nanostructures of TiO2 and ZnO for Water Splitting Application: Atomic Layer Deposition Growth and Density Functional Theory Investigation

The commercialization of solar fuel devices requires the development of novel engineered photoelectrodes for water splitting applications which are based on redundant, cheap, and environmentally friendly materials. In the current study, a combination of titanium dioxide (TiO₂) and zinc oxide (ZnO) onto nanotextured silicon is utilized for a composite electrode with the aim to overcome the individual shortcomings of the respective materials. The properties of conformal coverage of TiO₂ and ZnO layers are designed on the atomic scale by the atomic layer deposition technique. The resulting photoanode shows not only promising stability but also nine times higher photocurrents than an equivalent photoanode with a pure TiO₂ encapsulation onto the nanostructured silicon. Density functional theory calculations indicate that segregation of TiO₂ at the ZnO surfaces is favorable and leads to the stabilization of the ZnO layers in water environments. In conclusion, the novel designed composite material constitutes a promising base for a stable and effective photoanode for the water oxidation reaction.     

Interdigitated back‐contact heterojunction solar cell concept for liquid phase crystallized thin‐film silicon on glass

We present an interdigitated back‐contact silicon heterojunction system designed for liquid‐phase crystallized thin‐film (~10 µm) silicon on glass. The preparation of the interdigitated emitter (a‐Si:H(p)) and absorber (a‐Si:H(n)) contact layers relies on the etch selectivity of doped amorphous silicon layers in alkaline solutions. The etch rates of a‐Si:H(n) and a‐Si:H(p) in 0.6% NaOH were determined and interdigitated back‐contact silicon heterojunction solar cells with two different metallizations, namely Al and ITO/Ag electrodes, were evaluated regarding electrical and optical properties. An additional random pyramid texture on the back side provides short‐circuit current density (j_SC) of up to 30.3 mA/cm² using the ITO/Ag metallization. The maximum efficiency of 10.5% is mainly limited by a low of fill factor of 57%. However, the high j_SC, as well as V_OC values of 633 mV and pseudo‐fill factors of 77%, underline the high potential of this approach. Copyright © 2015 John Wiley & Sons, Ltd.     

Performance of PKI-based security mechanisms in mobile ad hoc networks

Security for ad hoc network environments has received a lot of attention as of today. Previous work has mainly been focussing on secure routing, fairness issues, and malicious node detection. However, the issue of introducing and conserving trust relationships has received considerably less attention. In this article, we present a scalable method for the use of public key certificates and their revocation in mobile ad hoc networks (MANETs). With the LKN-ad hoc security framework (LKN-ASF) a certificate management protocol has been introduced, bringing PKI technology to MANETs. In addition a performance analysis of two different revocation approaches for MANETs will be presented.     

Analysis of the Stakeholder Engagement in the Deployment of Renewables and Smart Grid Technologies

The implementation of higher shares of renewables in a global energy mix has to be accompanied by simultaneous deployment of enabling smart grid technologies (SGTs). This combination will inevitably lead to a revolutionary change in a conventional energy system, particularly, the shifting role of consumers to prosumers. But resistance may arise from such a dramatic shift, since it is associated with high uncertainty in conjunction with increasing responsibilities of all stakeholders, the urgent need of effective control, and the development of a process. To ensure the positive influence, coherent actions of all players, and appropriate treatment of the spots of resistance, the analysis of the interplay between key stakeholders has been done. The paper introduces the framework for stakeholders' analysis, applies it on the European Union (EU) example, and provides recommendations to reduce the resistance of SGTs deployment.