An optofluidic router in a low-cost (PDMS) platform for rapid parallel sample analysis

En col·laboració amb la Universitat de Barcelona (UB), la Universitat Autònoma de Barcelona (UAB) i l'Institut de Ciències Fotòniques (ICFO)Optofluidic system for (bio)chemical applications are becoming more demanding in terms of num- ber of control points, number of light sources and readout equipment. So far, most of these sys- tems require several light sources/detectors for suitable performance, increasing their complexity and cost. In this work, we present an easily integrated, fluidically controlled optical router that fa- cilitates coupling of several light sources or detectors. By using PDMS mirrors and phaseguides, the switching liquid is guided and pinned in desired angles, so that the incident light undergoes total internal reflection and can be reflected towards the output channels without any movable parts. The developed router presents ideal performance for lab on a chip applications, achieving switching frequencies between 0.07 ± 0.025 and 4 ± 2 Hz, depending on the flow rate of the switching liquid. The cross-talk levels are at 20 dB from channel output power to static noise level. With the use of parabolic mirrors, channel coupling efficiencies decrease just 2.38 dBm over four channels. The dynamic switching noise reduces the cross-talk levels by 2-5 dB, depending on the incorporation of ink-apertures. The insertion loss of these devices ranges from 17.34 to 25.42 dB. These results prove the viability of the fluidically controlled router in the low-cost PDMS platform. The intended goal of this work has been to simplify and speed up parallel sample analysis with the router integrated into a multiple path photonic component on a single chip. Development on this front is ongoing to rapidly measure methadone concentrations on chip

Robotic Wireless Sensor Networks

In this chapter, we present a literature survey of an emerging, cutting-edge, and multi-disciplinary field of research at the intersection of Robotics and Wireless Sensor Networks (WSN) which we refer to as Robotic Wireless Sensor Networks (RWSN). We define a RWSN as an autonomous networked multi-robot system that aims to achieve certain sensing goals while meeting and maintaining certain communication performance requirements, through cooperative control, learning and adaptation. While both of the component areas, i.e., Robotics and WSN, are very well-known and well-explored, there exist a whole set of new opportunities and research directions at the intersection of these two fields which are relatively or even completely unexplored. One such example would be the use of a set of robotic routers to set up a temporary communication path between a sender and a receiver that uses the controlled mobility to the advantage of packet routing. We find that there exist only a limited number of articles to be directly categorized as RWSN related works whereas there exist a range of articles in the robotics and the WSN literature that are also relevant to this new field of research. To connect the dots, we first identify the core problems and research trends related to RWSN such as connectivity, localization, routing, and robust flow of information. Next, we classify the existing research on RWSN as well as the relevant state-of-the-arts from robotics and WSN community according to the problems and trends identified in the first step. Lastly, we analyze what is missing in the existing literature, and identify topics that require more research attention in the future

Covert Ephemeral Communication in Named Data Networking

In the last decade, there has been a growing realization that the current Internet Protocol is reaching the limits of its senescence. This has prompted several research efforts that aim to design potential next-generation Internet architectures. Named Data Networking (NDN), an instantiation of the content-centric approach to networking, is one such effort. In contrast with IP, NDN routers maintain a significant amount of user-driven state. In this paper we investigate how to use this state for covert ephemeral communication (CEC). CEC allows two or more parties to covertly exchange ephemeral messages, i.e., messages that become unavailable after a certain amount of time. Our techniques rely only on network-layer, rather than application-layer, services. This makes our protocols robust, and communication difficult to uncover. We show that users can build high-bandwidth CECs exploiting features unique to NDN: in-network caches, routers' forwarding state and name matching rules. We assess feasibility and performance of proposed cover channels using a local setup and the official NDN testbed

ABC: A Simple Explicit Congestion Controller for Wireless Networks

We propose Accel-Brake Control (ABC), a simple and deployable explicit congestion control protocol for network paths with time-varying wireless links. ABC routers mark each packet with an "accelerate" or "brake", which causes senders to slightly increase or decrease their congestion windows. Routers use this feedback to quickly guide senders towards a desired target rate. ABC requires no changes to header formats or user devices, but achieves better performance than XCP. ABC is also incrementally deployable; it operates correctly when the bottleneck is a non-ABC router, and can coexist with non-ABC traffic sharing the same bottleneck link. We evaluate ABC using a Wi-Fi implementation and trace-driven emulation of cellular links. ABC achieves 30-40% higher throughput than Cubic+Codel for similar delays, and 2.2X lower delays than BBR on a Wi-Fi path. On cellular network paths, ABC achieves 50% higher throughput than Cubic+Codel