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Selective manipulation of micrometric objects in a standard microscopy environment is possible with miniaturized acoustical tweezers., Acoustical tweezers based on focalized acoustical vortices hold the promise of precise contactless manipulation of millimeter down to submicrometer particles, microorganisms, and cells with unprecedented combined selectivity and trapping force. Yet, the widespread dissemination of this technology has been hindered by severe limitations of current systems in terms of performance and/or miniaturization and integrability. Here, we unleash the potential of focalized acoustical vortices by developing the first flat, compact, paired single electrode focalized acoustical tweezers. These tweezers rely on spiraling transducers obtained by folding a spherical acoustical vortex on a flat piezoelectric substrate. We demonstrate the ability of these tweezers to grab and displace micrometric objects in a standard microfluidic environment with unique selectivity. The simplicity of this system and its scalability to higher frequencies open tremendous perspectives in microbiology, microrobotics, and microscopy.

Two mobile robots are initially placed at the same point on an infinite line. Each robot may move on the line in either direction not exceeding its maximal speed. The robots need to find a stationary target placed at an unknown location on the line. The search is completed when both robots arrive at the target point. The target is discovered at the moment when either robot arrives at its position. The robot knowing the placement of the target may communicate it to the other robot. We look for the algorithm with the shortest possible search time (i.e. the worst-case time at which both robots meet at the target) measured as a function of the target distance from the origin (i.e. the time required to travel directly from the starting point to the target at unit velocity). We consider two standard models of communication between the robots, namely wireless communication and communication by meeting. In the case of communication by meeting, a robot learns about the target while sharing the same location with a robot possessing this knowledge. We propose here an optimal search strategy for two robots including the respective lower bound argument, for the full spectrum of their maximal speeds. This extends the main result of Chrobak et al. (in: Italiano, Margaria-Steffen, Pokorný, Quisquater, Wattenhofer (eds) Current trends in theory and practice of computer science, SOFSEM, 2015) referring to the exact complexity of the problem for the case when the speed of the slower robot is at least one third of the faster one. In the wireless communication model, a message sent by one robot is instantly received by the other robot, regardless of their current positions on the line. For this model, we design a strategy which is optimal whenever the faster robot is at most \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sqrt{17}+4\approx 8.123$$\end{document}17+4≈8.123 times faster than the slower one. We also prove that otherwise the wireless communication offers no advantage over communication by meeting.

In this second part, images acquired from the specific trials developed in order to study the phenomenon of bubble sweep-down are analysed. A post-processing method has been developed to analyse the two air entrainment mechanisms described in the first part, for several test configurations. Bubble clouds are described in terms of depth, area and velocity for both vortex shedding and breakingwave bubble clouds. A parametric study is also performed to calculate the influence of each test parameter on the frequency of bubble generation. It is demonstrated that the occurrence of bubble clouds is proportional to the wave height, with a considerable influence of the phase shift between waves and motions. The overall results provide new elements for the understanding and the study of the phenomenon, with the final objective of obtaining a reliable tool that facilitates the design of research vessels. The authors gratefully acknowledge the DGA (the French Government Agency for Defense) and Ifremer for the financial support of this co-financed Ph.D. thesis. We also would like to thank Thomas Bacchetti and Jean-Valery Facq for their assistance in the design and set-up of these experiments, and Alcino Ferreira for the proof-reading of the final paper.

This paper frames a model which summarizes the principal factors and relationships to incorporate human element, as per fatigue engagement, in the strategic and tactical decision making. A characterization of humans as per a dynamic interferer in system is presented. The findings are tested in an U-shaped assembly division of an international motor company. Dual-Resource Constrained sets are proposed. A Multi Agent model architecture, incorporating system dynamics modelling per humans, is implemented. ANOVA is executed for interaction analyses. Results designed optimal job sequence, rest break and task’s sequence, recovery rate and load characters as per enhanced system’s performances. Stable fatigued conditions are under complete recovery. Production rate in system is affected by fatigue that in turn increases with rise in switching rate. Chaotic market behavior prefers decentralized assignment of worker to task. Continuous switching suffers from learning attitude. Chaotic demand impairs fatigue across workforce reporting instable operator fatigue under different allocation rules. Under loudly physical tasks, random assignment is preferable for productivity outcomes. Autonomous control of workers at work considerably impairs fatigue under complete resting schema.

This paper presents three transistors (3T) based Dynamic Random Access Memory (DRAM) cell in which noise, static power, and data retention voltage (DRV) have been reduced. The spesified parameters in the proposed eDRAM gain cell were improved by connecting the source of storage device to the read word line signal instead of supply voltage. As we all know, power consumption plays a vital role in VLSI design and thus, it is enumerated among the top challenges for the semiconductor chip industries. With the intention to maintain the performance of write operation, we diminish DRV and increase the read margin of eDRAM cell with our designed circuit which is introduced as “A Boosted 3T eDRAM gain cell”. It is a kind of eDRAM cell that utilizes a read word line (RWL) via three PMOS transistors instead of NMOS transistors. PMOS devices are preferred as they have radically less gate leakage current, which confer better results for data retention and thus, boost up the read margin of the cell. Simulation results have been obtained by using Cadence Virtuoso Tool at 45 nm technology for the proposed model. Based on simulation results we can conclude that the parameters of the proposed eDRAM gain cell essentially improved as compared with convertional eDRAM gain cell and the achieved parameters are as follows: static power is 0.767 pW, DRV is 142.009 mV and noise is 8.421 nV/Hz1/2.

Creep-age-forming of a thick Al-Cu-Li sheet is studied. An industrial stamping press is used to form a double curvature panel at a reduced scale. This forming, which includes several relaxation steps, is modelled using ABAQUS. A material model describing an elasto-viscoplastic behaviour with anisotropy effect has been identified and implemented in ABAQUS using Fortran subroutine. The numerical model is validated by comparing experiments and numerical results in terms of deformed shapes and an improved forming cycle is suggested. This paper is part of the METAFOR project managed by IRT Jules Verne (French Institute in Research and Technology in Advanced Manufacturing Technologies for Composite, Metallic and Hybrid Structures). The authors wish to associate the industrial and academic partners of this project; respectively ACB, STELIA, AIRBUS, CONSTELLIUM, ENSAM.

This article presents a summary of the Strategic Management Accounting (SMA) literature. In its first part, the article shows how authors define SMA (by its characteristics, its practices and methods) and compares SMA to Strategic Cost Management (SCM). The second part of the article discusses the empirical research work conducted in the SMA/SCM field and its main results. The article then questions the theoretical contribution of the SMA/SCM literature and its limitations before proposing a framework which relates the concepts of costs, value and price, and incorporates many of the practices usually connected to SMA.

This paper examines the relationship among IT capability, operations strategy decisions and operational performance. Using primary data from a sample of European firms, the authors test a model of fit between two specific IT capability-building decisions and three competitive priorities, and they analyze the impact of IT capability alignment on several dimensions of process performance. After uncovering three stylized configurations, they note that firms tend to adopt internally coherent IT capability-building decisions but they find only mixed evidence of alignment between IT capability-building decisions and competitive priorities. Interestingly, however, failing to achieve alignment has negative performance consequences but only for firms that develop limited IT capability. Their results suggests that IT plays a central role in the fulfillment of a firm’s operations strategy, not only for firms that pursue differentiation and are interested in improving the effectiveness of their customer-oriented functions, but also for firms seeking efficiency improvements in back-office operations. Although it is, a priori, more expensive, the development of advanced IT capability can support cost leadership strategies more effectively than a frugal approach, as long as IT projects are used to generate operational knowledge and thus improve process efficiency. At the same time, their results cast further doubt on the value of frugal IT capability, even for firms that strive to reduce cost.

Whereas systems integration is recognized as an important organizational capability, the mechanisms through which it creates value as well as the environmental contingencies that delimit its effectiveness remain unclear, particularly when firms deliver integrated solutions embodying products and services. Focusing on IT solution providers, we investigate the effectiveness of systems integration with respect to three specific approaches to solution design: breadth, modularity, and customization. We find a complementarity effect between systems integration and solution design approaches: if firms pursue customization or rely on a broad set of heterogeneous knowledge bases, systems integration becomes fundamental. Conversely, if firms adopt a modular design, systems integration is redundant and even counterproductive. We also find evidence of complementarity between breadth and customization, but not between breadth and modularity nor between customization and modularity.

The important role of entrepreneurship in the dynamics of the arts sector and the influence of the leader’s personality make succession a key issue in creative industries. What happens to an artistic organization when its founder leaves? How does it evolve? Can it adopt a style of management that is compatible with the founder’s absence? This article focuses on the case of Groupe Bernard Loiseau, an iconic French company in the culinary arts whose owner and chef died suddenly. It sheds light on how the question of succession and that of style were addressed in this organization and how they are addressed in artistic organizations in general.

International audience; Shadowing is believed to degrade the quality of service (QoS) in wireless cellular networks. Assuming log-normal shadowing, and studying mobile's path-loss with respect to the serving base station (BS) and the corresponding interference factor (the ratio of the sum of the path-gains form interfering BS's to the path-gain from the serving BS), which are two key ingredients of the analysis and design of the cellular networks, we discovered a more subtle reality. We observe, as commonly expected, that a strong variance of the shadowing increases the mean path-loss with respect to the serving BS, which in consequence, may compromise QoS. However, in some cases, an increase of the variance of the shadowing can significantly reduce the mean interference factor and, in consequence, improve some QoS metrics in interference limited systems, provided the handover policy selects the BS with the smallest path loss as the serving one. We exemplify this phenomenon, similar to stochastic resonance and related to the ''single big jump principle'' of the heavy-tailed log-nornal distribution, studying the blocking probability in regular, hexagonal networks in a semi-analytic manner, using a spatial version of the Erlang's loss formula combined with Kaufman-Roberts algorithm. More detailed probabilistic analysis explains that increasing variance of the log-normal shadowing amplifies the ratio between the strongest signal and all other signals thus reducing the interference. The above observations might shed new light, in particular on the design of indoor communication scenarios.

International audience; This paper proposes a Fuzzy Dedicated Observers (FDOS) method using a Nonlinear Unknown Input Fuzzy Observer (UIFO) with a Fuzzy Fault Tolerant Control (FFTC) algorithm for fuzzy Takagi-Sugeno (TS) systems subject to sensor faults. FDOS provide residuals for detection and isolation of sensor faults which can affect a TS model. Parallel Distributed Compensation (PDC) is employed to design the fuzzy Fault Tolerant Controller from a TS fuzzy model. Sufficient stabilization conditions of the FFTC systems are given, which are formulated in terms of Linear Matrix Inequalities (LMIs). The LMIs can be efficiently solved using convex optimization techniques. Based on the derivation and simulation of the proposed FFTC approach, the stability of the closed-loop system in the event of sensor failures and unknown inputs is guaranteed. A wind Energy System (WES) with a Doubly-Fed Induction Generator (DFIG) example is illustrated to show the effectiveness of the proposed design method.

International audience; The six axis robots are widely used in automotive industry for their good repeatability (as defined in the ISO92983) (painting, welding, mastic deposition, handling etc.). In the aerospace industry, robot starts to be used for complex applications such as drilling, riveting, fiber placement, NDT, etc. Given the positioning performance of serial robots, precision applications require usually external measurement device with complexes calibration procedure in order to reach the precision needed. New applications in the machining field of composite material (aerospace, naval, or wind turbine for example) intend to use off line programming of serial robot without the use of calibration or external measurement device. For those applications, the position, orientation and path trajectory precision of the tool center point of the robot are needed to generate the machining operation. This article presents the different conditions that currently limit the development of robots in robotic machining applications. We analyze the dynamical behavior of a robot KUKA KR240-2 (located at the University of Bordeaux 1) equipped with a HSM Spindle (42000 rpm, 18kW). This analysis is done in three stages. The first step is determining the self-excited frequencies of the robot structure for three different configurations of work. The second phase aims to analyze the dynamical vibration of the structure as the spindle is activated without cutting. The third stage consists of vibration analysis during a milling operation.

International audience; This paper proposes a method to vibration analysis in order to on-line monitoring of milling process quality. Adapting envelope analysis to characterize the milling tool materials is an important contribution to the qualitative and quantitative characterization of milling capacity and a step by modeling the three-dimensional cutting process. An experimental protocol was designed and developed for the acquisition, processing and analyzing three-dimensional signal. The vibration envelope analysis is proposed to detect the cutting capacity of the tool with the optimization application of cutting parameters. The research is focused on Hilbert transform optimization to evaluate the dynamic behavior of the machine/ tool/workpiece.

International audience; Being an optimizing technology, model predictive control (MPC) can now be found in a wide variety of application fields. The main and most obvious control goal to be achieved in a wastewater treatment plant is to fulfill the effluent quality standards, while minimizing the operational costs. In order to maintain the effluent quality within regulation-specified limits, the MPC strategy has been applied to the Benchmark Simulation Model 1 (BSM1) simulation benchmark of wastewater treatment process. After the discussion of open loop responses of outputs to manipulated inputs and measured influent disturbances, the strategies of feedback by linear dynamic matrix control (DMC), quadratic dynamic matrix control (QDMC) and nonlinear model predictive control (NLMPC), and improvement by feedforward based on influent flow rate or ammonium concentration have been investigated. The simulation results indicate that good performance was achieved under steady influent characteristics, especially concerning the nitrogen-related species. Compared to DMC and QDMC, NLMPC with penalty function brings little improvement. Two measured disturbances have been used for feedforward control, the influent flow rate and ammonium concentration. It is shown that the performance of feedforward with respect to the influent ammonium concentration is much higher than for the feedforward with respect to the influent flow rate. However, this latter is slightly better than the DMC feedback. The best performance is obtained by combining both feedforward controllers with respect to the influent ammonium concentration and flow rate. In all cases, the improvement of performance is correlated with more aeration energy consumption

Recently, IEEE 802.15.4a has specified a UWB PHY for low-rate commutation with ranging capability for wireless personnel area and sensor network applications [1]. Related work is reported on low-rate energy-efficient UWB radios [2-4]. However, they are not fully standard compliant or localization enabled. 802.15.4a supports three bands of operation, i.e., sub-1GHz band (249.6 to 749.6MHz), low band (3.1 to 4.8GHz) and high band (6.0 to 10.6GHz) with 16 channels in total. A combination of the burst position modulation (BPM) and binary phase shift keying (BPSK) is adopted. With different coding rate, bursts per symbol, and chips per burst, the mean pulse repetition rate (PRF) could vary from 3.9 to 62.4MHz for data throughput of 120kHz to 31.2MHz. This work presents an UWB RF transceiver which supports 12 channels, variable date rate, and ranging capability as specified in IEEE802.15.4a. Published version