Eugen Dedu

Distributed control architecture for smart surfaces

This paper presents a distributed control architecture to perform part recognition and closed-loop control of a distributed manipulation device. This architecture is based on decentralized cells able to communicate with their four neighbors thanks to peer-to-peer links. Various original algorithms are proposed to reconstruct, recognize and convey the object levitating on a new contactless distributed manipulation device. Experimental results show that each algorithm does a good job for itself and that all the algorithms together succeed in sorting and conveying the objects to their final destination. In the future, this architecture may be used to control MEMS-arrayed manipulation surfaces in order to develop Smart Surfaces, for conveying, fine positioning and sorting of very small parts for micro-systems assembly lines.

An Exhaustive Comparison Framework for Distributed Shape Differentiation in a MEMS Sensor Actuator Array

The Smart Surface1 project aims at designing an integrated micro-manipulator based on an array of micromodules connected in a 2D array network. Each micromodule has a sensor, an actuator and a processing unit. One of the aims of the processing unit is to recognize the shape of the part that is put on top of the smart surface. This recognition or more precisely this differentiation is done through a distributed algorithm that we call a criterion. The aim of this article is to present the ECO framework, which is able to test exhaustively the efficiency of different differentiation criteria, in terms of differentiation efficiency, memory and processing power needed. The tests show that ECO is of great help for choosing the best criteria to implement inside our smart surface.

Coordination and Computation in Distributed Intelligent MEMS

Over the last decades, research on microelectromechanical systems (MEMS) has focused on the engineering process which has led to major advances. Future challenges will consist in adding embedded intelligence to MEMS systems to obtain distributed intelligent MEMS. One intrinsic characteristic of MEMS is their ability to be mass-produced. This, however, poses scalability problems because a significant number of MEMS can be placed in a small volume. Managing this scalability requires paradigm-shifts both in hardware and software parts. Furthermore, the need for actuated synchronization, programming, communication and mobility management raises new challenges in both control and programming. Finally, MEMS are prone to faulty behaviors as they are mechanical systems and they are issued from a batch fabrication process. A new programming paradigm which can meet these challenges is therefore needed. In this article, we present CO2Dim, which stands for Coordination and Computation in Distributed Intelligent MEMS. CO2DIM is a common project between France and Hong-Kong building a new programming environment which includes a language, based on a joint development of programming and control capabilities, a simulator and real hardware.

Hybrid prognostic approach for Micro-Electro-Mechanical Systems

This paper presents a hybrid prognostic approach which is applied on electro-thermally actuated MEMS valve. The method can be applied on different categories of MEMS to assess their health state, calculate the remaining useful life (RUL) and take appropriate decisions to anticipate the failures. In this paper a detailed description of the proposed method is presented. It consists of combining both degradation and nominal behavior models in order to estimate the current and future MEMS health states. A test bed for several MEMS is designed to acquire data in relation with the health state of the MEMS. The data processing obtained with this platform aims at deriving degradation models. Physical modeling is used to build the nominal behavior model of the valve. To show the effectiveness of the proposed method and in order to validate the implementation of Prognostics and Health Management (PHM) models on MEMS, two simulated degradations of the valve MEMS are considered.

Video quality estimation of DCCP streaming over wireless networks

This paper describes a streaming architecture simulation model above network simulator 2 (NS2) which allows to define specific transport properties. Multimedia contents are specific because they are time-dependent and they can undergo small deterioration if necessary. We simulate such a congestion control that has the ability to decrease the multimedia quality in case of network congestion in order to decrease packet losses and packet delivery delays. We integrate this video TFRC congestion control inside DCCP (datagram congestion control protocol) and TFRC (TCP friendly rate control). The transcoding of the multimedia contents is realized thanks to the NetMoVie simulation model which is an RTP mixer. We compare the adaptive transport solution to the classic transport solution without any adaptive mechanism. The peak signal-to-noise ratio (PSNR) of the received multimedia contents is measured and compared for better visualization.

Packet routing in 3D nanonetworks: A lightweight, linear-path scheme

Packet routing in nanonetworks requires novel approaches, which can cope with the extreme limitations posed by the nano-scale. Highly lossy wireless channels, extremely limited hardware capabilities and non-unique node identifiers are among the restrictions. The present work offers an addressing and routing solution for static 3D nanonetworks that find applications in material monitoring and programmatic property tuning. The addressing process relies on virtual coordinates from multiple, alternative anchor point sets that act as \emph{viewports}. Each viewport offers different address granularity within the network space, and its selection is optimized by a packet sending node using a novel heuristic. Regarding routing, each node can deduce whether it is located on the linear segment connecting the sender to the recipient node. This deduction is made using integer calculations, node-local information and in a stateless manner, minimizing the computational and storage overhead of the proposed scheme. Most importantly, the nodes can regulate the width of the linear path, thus trading energy efficiency (redundant transmissions) for increased path diversity. This trait can enable future adaptive routing schemes. Extensive evaluation via simulations highlights the advantages of the novel scheme over related approaches.

A hybrid prognostics approach for MEMS: From real measurements to remaining useful life estimation

Abstract This paper presents a hybrid prognostics approach for Micro Electro Mechanical Systems (MEMS). This approach relies on two phases: an offline phase for the MEMS and its degradation modeling, and an online phase where the obtained degradation model is used with the available data for prognostics. In the online phase, the particle filter algorithm is used to perform online parameters estimation of the degradation model and predict the Remaining Useful Life (RUL) of MEMS. The effectiveness of the proposed approach is validated on experimental data related to an electro-thermally actuated MEMS valve.

A taxonomy of the parameters used by decision methods for adaptive video transmission

Nowadays, video data transfers account for much of the Internet traffic and a huge number of users use this service on a daily base. Even if videos are usually stored in several bitrates on servers, the video sending rate does not take into account network conditions which are changing dynamically during transmission. Therefore, the best bitrate is not used which causes sub-optimal video quality when the video bitrate is under the available bandwidth or packet loss when it is over it. One solution is to deploy adaptive video, which adapts video parameters such as bitrate or frame resolution to network conditions. Many ideas are proposed in the literature, yet no paper provides a global view on adaptation methods in order to classify them. This article fills this gap by discussing several adaptation methods through a taxonomy of the parameters used for adaptation. We show that, in the research community, the sender generally takes the decision of adaptation whereas in the solutions supported by major current companies the receiver takes this decision. We notably suggest, without evaluation, a valuable and realistic adaptation method, gathering the advantages of the presented methods.

A Framework to Calibrate a MEMS Sensor Network

The Smart Surface project aims at designing an integrated micro-manipulator based on an array of micromodules connected with a 2D array topology network. Each micromodule comprises a sensor, an actuator and a processing unit. One of the aims of the processing unit is to differentiate the shape of the part that is put on top of the Smart Surface. From a set of shapes this differentiation is done through a distributed algorithm that we call a criterion. The article presents Sensor Network Calibrator (SNC), a calibrator which allows to parametrize the Smart Surface and to determine the necessary number of sensors required by our Smart Surface. The tests will show that SNC is of great importance for choosing the number of sensors, and therefore to determine the size of the sensors grid.

Optimal Path Evolution in a Dynamic Distributed MEMS-Based Conveyor

We consider a surface designed to convey fragile and tiny micro-objects. It is composed of an array of decentralized blocks that contain MEMS valves. We are interested in the dynamics of the optimal path between two blocks in the surface. The criteria used for optimal paths are related to the degradation of the MEMS, namely its remaining useful life and its transfer time. We study and analyze the evolution of the optimal path in dynamic conditions in order to maintain as long as possible a good performance of the conveying surface. Simulations show that during usage the number of optimal paths increases, and that position of sources greatly influences surface lifetime.