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International audience; The development of endocavitary dual-mode probes is essential for the accurate treatment of many deep seated cancers which require a high imaging resolution and the capacity to selectively treat focal areas in the region of interest. The MULTIP project is aimed at using state-of-art piezoelectric technologies to design dual-mode ultrasonic probes for cancer-foci treatment and monitoring. In order to allow an efficient surgery planning, the technical study has been accompanied by a volume processing study permitting the design of the ultrasonic imaging/therapy process based on high-resolutionhigh-quality MRI images. Several prototypes were designed based on a simulation study and implemented: 1) two successive wide-band dual-mode transducer allowing imaging at high resolution (6 MHz) on a wide field of view, and therapy at 3 MHz with a good transduction efficiency (48% and 70%); 2) a therapy-only transducer matrix adapted to the desired curvature with a high transduction efficiency (70%). Finally, a registration study of MRI volumes on ultrasound volumes has shown that, because of the texture of the ultrasound images, it is more efficient to search at registering the surfaces of the volumes once they have been segmented in each modality, rather than trying to register the two data volumes directly.

Potential applications of High Intensity Therapeutic Ultrasound (HITU) are numerous. Some commercial devices already exist to treat for instance prostate cancers or uterine fibroids. Strong technical and clinical research effort is also being made to validate systems and treatment procedures for various organs: for instance, breast, liver, kidney, thyroid and even brain. Many other applications are under investigation or to be explored in the future. This diversity of applications leads to requirements for the transducer which are specific to each application and significantly different from one case to another. In this paper, specifications of HITU transducers are discussed in relation to different conditions of use. The first criterion that determines the design of the transducer is the way chosen to reach the organ to be treated: treatment can be performed from outside the body, through a natural cavity or by interstitial means. The size and geometry of the radiating surface, the acoustic power level and the operation frequency are then specified for each configuration. Starting from these requirements, a dedicated transducer is designed. Different technological solutions are available including piezocomposite technologies widely used in current HITU transducer design. An important point to take into account at this stage is the imaging method used for locating the area to be treated, positioning the transducer and finally monitoring the treatment. Ultrasound Imaging or Magnetic Resonance Imaging is generally chosen in HITU procedures. The HITU transducer has to be compatible with the specified imaging environment. After manufacture, the performance of the transducer is evaluated with respect to expected characteristics. Specific methods have been developed for this purpose such as, for instance, the radiation force balance with a liquid target to evaluate the total output power or acoustic holography to estimate acoustic field parameters. All recent developments in HITU transducer design and characterisation are driven by the needs of HITU procedures to provide a better medical service: quicker treatment, less expensive total procedure including hospitalisation time, safety for the patient, and efficiency evaluated with respect to alternative methods. These developments will be reinforced by the availability of dedicated imaging methods allowing better monitoring of the treatment, but also by the elaboration of standards currently under preparation concerning the characterisation of HITU systems from the acoustic and safety point of view.

Interstitial ultrasound applicators can be a minimally invasive alternative for treating targets that are unresectable or are inaccessible by extracorporeal methods. Dual-mode transducers for ultrasound imaging and therapy were developed to address the constraints of a miniaturized applicator and real-time treatment monitoring. We propose an original treatment strategy that combines ultrasound imaging and therapy using a dual-mode transducer rotating at 8 revolutions per second. Real-time B-mode imaging was interrupted to emit high-intensity ultrasound over a selected therapy aperture. A full 360 degrees image was taken every 8th rotation to image the therapy aperture. Numerical simulations were performed to study the effect of rotation on tissue heating, and to study the effect of the treatment sequence on transducer temperature. With the time-averaged transducer surface intensity held at 12 W/cm(2) to maintain transducer temperature below 66 degrees C, higher field intensities and deeper lesions were produced by narrower therapy apertures. A prototype system was built and tested using in vitro samples of porcine liver. Lesions up to 8 mm were produced using a time-averaged transducer surface intensity of 12 W/cm(2) applied for a period of 240 s over a therapy aperture of 40 degrees. Apparent strain imaging of the therapy aperture improved the contrast between treated and spared tissues, which could not be differentiated on B-mode images. With appropriate limits on the transducer output, real-time imaging and deep thermal ablation are feasible and sustainable using a rotating dual-mode transducer.

Medical imaging is a vital component of high intensity focused ultrasound (HIFU) therapy, which is gaining clinical acceptance for tissue ablation and cancer therapy. Imaging is necessary to plan and guide the application of therapeutic ultrasound, and to monitor the effects it induces in tissue. Because they can transmit high intensity continuous wave ultrasound for treatment and pulsed ultrasound for imaging, dual-mode transducers aim to improve the guidance and monitoring stages. Their primary advantage is implicit registration between the imaging and treatment axes, and so they can help ensure before treatment that the therapeutic beam is correctly aligned with the planned treatment volume. During treatment, imaging signals can be processed in real-time to assess acoustic properties of the tissue that are related to thermal ablation. Piezocomposite materials are favorable for dual-mode transducers because of their improved bandwidth, which in turn improves imaging performance while maintaining high efficiency for treatment. Here we present our experiences with three dual-mode transducers for interstitial applications. The first was an 11-MHz monoelement designed for use in the bile duct. It had a 25 × 7.5 mm 2 aperture that was cylindrically focused to 10 mm. The applicator motion was step-wise rotational for imaging and therapy over a 360°, or smaller, sector. The second transducer had 5-elements, each measuring 3.0 × 3.8 mm 2 for a total aperture of 3.0 × 20 mm 2 . It operated at 5.6 MHz, was cylindrically focused to 14 mm, and was integrated with a servo-controlled oscillating probe designed for sector imaging and directive therapy in the liver. The last transducer was a 5-MHz, 64-element linear array designed for beam-formed imaging and therapy. The aperture was 3.0 × 18 mm 2 with a pitch of 0.280 mm. Characterization results included conversion efficiencies above 50%, pulse-echo bandwidths above 50%, surface intensities up to 30 W / cm 2 , and axial imaging resolutions to 0.2 mm. The second transducer was evaluated in vivo using porcine liver, where coagulation necrosis was induced up to a depth of 20 mm in 120 s. B-mode and M-mode images displayed a hypoechoic region that agreed well with lesion depth observed by gross histology. These feasibility studies demonstrate that the dual-mode transducers had imaging performance that was sufficient to aid the guidance and monitoring of treatment, and could sustain high intensities to induce coagulation necrosis in vivo.

Interstitial probes have been shown as effective devices to deliver high-intensity ultrasound therapy. Here, cylindrically-focused dual-mode transducers with either one or 5-elements were characterized, and a monoelement probe was evaluated in vitro. In therapy mode, the transducers were maximally efficient (or =70%) at 5.6 MHz with surface intensities up to 20 W/cm(2). In imaging mode, fractional bandwidths were 46% and 50+/-4% (ave+/-std) for the monoelement and 5-element transducers respectively. Axial and lateral resolutions were 0.5 mm and 1.0 mm, respectively, for both transducers as measured with a point scatterer in the focal plane. After characterization, the oscillating probe was used to image and apply therapy to porcine liver. B-mode images over a 140 degrees sector were formed before and after therapy, which was applied for 90 s at each of 5 angles separated by 20 degrees (e.g. -40 degrees , -20 degrees, 0 degrees, 20 degrees, 40 degrees) to form a composite lesion. Transducer surface intensity was 18 W/cm(2). Therapy was interrupted at 125 ms intervals to collect pulse/echo data along the therapy axes. Data were displayed in real-time as an M-mode image to monitor therapy. B-mode images adequately represented the liver tissue. M-mode image data agreed well with the formation of lesions in the liver.

The Capacitated Arc Routing Problem (CARP) occurs in applications like urban waste collection or winter gritting. It is usually defined in literature on an undirected graph G = (V, E) , with a set V of n nodes and a set E of m edges. A fleet of identical vehicles of capacity Q is based at a depot node. Each edge i has a cost (length) ci and a demand qi (e.g. an amount of waste), and it may be traversed any number of times. The edges with non-zero demands or tasks require service by a vehicle. The goal is to determine a set of vehicle trips (routes) of minimum total cost, such that each trip starts and ends at the depot, each task is serviced by one single trip, and the total demand handled by any vehicle does not exceed Q . To the best of our knowledge the best published method is a memetic algorithm first introduced in 2001. This article provides a new extension of the NSGA II (Non-dominated Sorting Genetic Algorithm) template to comply with the stochastic sight of the CARP. The main contribution is: - to introduce mathematical expression to evaluate both cost and duration of the longest trip and also standard deviation of these two criteria. - to use a NGA-II template to optimize simultaneously the cost and the duration of the longest trip including standard deviation. The numerical experiments managed on the thee well-known benchmark sets of DeArmon, Belenguer and Benavent and Eglese, prove it is possible to obtain robust solutions in four simultaneous criteria in rather short computation times.

Deep‐seated tumours can be treated by high intensity interstitial ultrasound using a miniature transducer brought in contact with the target. A dual mode transducer was designed for performing simultaneous imaging. Two therapeutic strategies are envisaged in this study. First, the transducer can be rotated step‐by‐step and therapy interrupted periodically for acquiring echo lines. In a second approach, fast rotation of the transducer allows 2D‐imaging and therapy is applied transiently over a small angular sector. Simultaneous imaging and therapy were performed in vitro with the designed transducer (2.5×7.5mm2, cylindrically focused at 10mm, 11MHz) following these two approaches. Up to 10mm deep lesions were obtained with the immobile transducer emitting an intensity of 17W/cm2 for 120s. M‐mode images were constructed on‐line during treatment. For the second strategy, the transducer rotated at a 7 rotations per second pace. Each turn, imaging was interrupted for ≈0.02s in order to perform therapy at insta...

High intensity focused ultrasound has been shown to be very effective for thermally ablating localised tumours through extracorporeal or endocavitary routes. More recently, miniature interstitial ultrasound probes have been investigated for the treatment of deep-seated tumours. All treatments must be performed under imaging guidance in order to bring the probe focus precisely on the targeted site and to monitor the treatment on-line. Imaging objectives and constraints may vary depending on the targeted organs, access routes, and treatment process. MRI provides high contrast images and is presently recognized as the gold standard for thermal mapping. MRI compatible high intensity ultrasound transducers have been designed for this purpose. Conventional B mode imaging is efficient at visualising scattering gas bodies. Many other ultrasound techniques have been tested and are likely to be further developed in order to make use of the large potential of ultrasound for targeting and monitoring the treatments. More recently it has been shown that dual mode transducers can be used for both imaging and therapeutic objectives. This again opens new possibilities for extracorporeal, endo-cavitary and interstitial applications. In all the cases, the therapeutic transducer has to be designed with the chosen imaging modality in mind

A cylindrical ultrasonic array has been developed for operating environments that can reach extremes of 175 C and 20,000 psi. The array is a key component of the PharUSIT (Phased Array Ultrasonic Transducer for Inspection of Tubing), a research demonstrator developed for borehole applications. The full array consists of 800 elements (10 rings of 80 elements each) and can provide a whole range of beam-forming versatilities and capabilities in 3D, such as variable focusing, beam steering, electronic scanning, etc, all accomplished without mechanical movements. Special piezocomposites have been developed for the transduction layer, and new polymeric composites have been formulated for the backing material. The center frequency was chosen to be about 500 kHz to accommodate attenuation of the propagation media. A novel technique utilizing custom flexible circuit provides electrical connections between the array and the front-end electronics. Special fabrication processes have been developed to construct the array in a cylindrical geometry. A customized testing protocol has been implemented to demonstrate the survivability of the array technology and to evaluate the performance characteristics of individual elements under high-temperature/high-pressure conditions. Data from electroacoustic measurements such as electrical impedance, bandwidth, sensitivity, angular directivity, and inter-element cross-talks will be shown

It has been shown that a very deep and selective interstitial thermal therapy can be performed using a rotating flat miniature ultrasound transducer. This heating modality would be significantly improved by implementing imaging and monitoring. The space limitations in interstitial applications require combining imaging and therapy on the same transducer. In conventional endoscopic ultrasound imaging, a miniprobe can be positioned inside the lumen of an organ and fast rotation of a single element transducer enables real time peripheral imaging of the lumen. Based on this idea, we proposed an original therapeutic strategy. Imaging can be interrupted for a short period of time corresponding to an angle Deltaalpha in order to apply high intensity ultrasound for thermal ablation. First, theoretical simulations were conducted. A 1D thermal model of the transducer demonstrated that this operating mode is not critical for the transducer. Simulations using the BioHeat Transfer Equation showed that Deltaalpha=pi/4 induced efficient therapy. An applicator was built in order to test this treatment strategy. The active element consisted in a 2.5 times 7.5 mm2 dual mode single element transducer operating at a frequency of 11 MHz. The applicator was driven in rotation at 7-turns per second pace. Experiments were performed in vitro on porcine liver. Ultrasound images were reconstructed and the size of the -6 dB point spread function at focal distance was 0.55 mm times 0.25 mm. The electronics for performing the therapeutic strategy considered above was set up. Up to 8 millimeters-deep thermal lesions were obtained with Deltaalpha=pi/4 and peak intensity of 110 W/cm 2. This work demonstrated that thermal lesions can be performed with a fast-rotating dual mode transducer. This approach enabled real-time image-guided therapy

International audience; The Capacitated Arc Routing Problem (CARP) is a combinatorial optimization problem in which vehicles with limited capacity must treat a set of arcs in a network, to minimize the total cost of the trips. The SCARP is a stochastic version with random demands on the arcs. The management rules used for instance in waste collection enable to derive mathematical expressions for objectives like the expected total cost. A memetic algorithm (MA) for the SCARP is proposed and compared with two deterministic versions based on average demands. All solutions are evaluated by simulation, to see how they are affected by random fluctuations of demands. This evaluation confirms the expected cost computed by the MA and shows its ability to provide robust solutions, without significant enlargement of the cost of planned trips.

The development of therapeutic ultrasound requires specially adapted transducers for the generation of high intensity focused beams. New piezocomposite technologies have been developed to take into account the high power requirements and constraints like the high degree of focussing, the capability to withstand thermal shocks, the requirement for safe and reliable transducers, the compatibility with MRI and Ultrasonic imaging systems. This approach enables a wide variety of shapes and the design of array transducers for electronic focusing, scanning and steering of the therapeutic beam. Recent results will be presented on power and efficiency aspects. The feasibility of highly focused transducers with several array structures as well as the combination of these technologies with MRI and Ultrasonic imaging systems will be illustrated through various examples.

International audience

After a presentation of the problem: crew scheduling for drivers in an urban transit company, we exhibit the difficulties of this kind of optimization problem.

For scheduling in manufacturing systems, the make-span, or total flow time, is the difference between the output date of the last job on the last machine, and the input date of the first job on the first machine. The problem is to find a schedule which minimises the make-span.

Miniature dual‐mode transducers can be used for minimally invasive treatment of deep‐seated tumors. While in contact with the tissue, the transducer guides and monitors localized necrosis. Here, an oscillating 5‐element piezo‐composite transducer was characterized, and then evaluated in vitro using porcine liver. Each element was 3.0 x 3.8 mm2 with a geometric cylindrical focus of 14 mm. The transmit frequency was determined by the maximal electro‐acoustic efficiency, 65%, which was found at 5.6 MHz. The transmit‐receive impulse response was 400 ns long at ‐6 dB, and the ‐6 dB fractional bandwidth, centered at 5.6 MHz, was 30%. Axial and lateral resolution measured with a 0.1 mm diameter wire was 0.5 mm and 2.0 mm, respectively. For therapy, all elements radiated simultaneously, and for imaging, independently. Treatment was performed at increments of 20° to form a composite volume of necrosis. At each angle, ultrasound was applied for 60 s at a transducer surface intensity of 15 W/cm2. Pulse‐echo data wer...

A cylindrical ultrasonic array has been developed for operating environments that can reach extremes of 175 C and 20,000 psi. The array is a key component of the PharUSIT* (Phased Array Ultrasonic Transducer for Inspection of Tubing), a research demonstrator developed for borehole applications. The full array consists of 800 elements (10 rings of 80 elements each) and can provide a whole range of beam‐forming versatilities and capabilities in 3‐D, such as variable focusing, beam steering, electronic scanning, etc, all accomplished without mechanical movements. Special piezo‐composites have been developed for the transduction layer, and new polymeric composites have been formulated for the backing material. The center frequency was chosen to be about 500 kHz to accommodate attenuation of the propagation media. A novel technique utilizing custom flexible circuit provides electrical connections between the array and the front‐end electronics. Special fabrication processes have been developed to construct the...

International audience; Reconfigurable Manufacturing Systems (RMS) have been defined in (Mehrabi et al., 2000) as an effective approach to deal with unpredictable and high-frequency market changes that are facing industries. To cope with such changes, the production systems must be adaptive and able to evolve in order to consider 1) changes in parts of existing products; 2) fluctuations in demands; 3) evolution in legal regulations and 4) evolution in process technology. Meanwhile, the scheduled operations remain partially manual like material handling, carrying and processing jobs as stressed by (Napolitano, 2012). The assignment of operators to operations must include personal skills, training and experience in order to match the competences and/or functionalities required by the operations to be performed (Ferjani et al., 2017; Grosse et al., 2015). In RMS, the sequential execution of operations may depends on the job operation sequence that can refer to Flow-shop, Job-shop, etc. Including flexibility for processing operations remains possible at each step of the job-sequence. Meanwhile, reconfigurability is the capacity of a set of machines to be reconfigured in a period of time, which can be seen as setup times. Machine activation delay may include cleaning the working zone, loading, positioning and unloading the parts (jobs) and can imply costs coming from energy expenditures, equipment maintenance and labor as stressed by (Borgia et al., 2013). Hence, in RMS a solution is composed by a set of configurations applied sequentially and thus a sequence-dependent processing time of operations and sequence dependent setup times have to be considered in such a production system. If sequence depend setup times are features of several research projects in the scheduling community as stressed in (Sharma and Jain, 2016; Shen et al., 2018), these works generally consider setup times at the operation level, whereas several modifications of the system may occur in RMS requiring several resources to be inactive during reconfigurations...

Sedentary behavior and inactivity are behaviors that are associated with obesity. The aim of this study was to classify 109 adult participants of various BMI in different homogeneous clusters on the basis of time spent at four physical activity levels. The cluster analysis tree shows three distinct clusters. The clusters significantly differed in BMI, hip circumference, and time spent in sedentary and active behaviors. The largest difference between clusters dealt with sedentary time: higher in CL2 (13 normal weight and 33 overweight) than in CL1 (33 normal weight and 20 overweight) and CL3 (9 normal weight and 1 overweight). Overweight is also associated with brief time in light- or moderate-intensity activities. However, some normal-weight adults had the same sedentary pattern as obese individuals. Factors other than physical activity or sedentary time might be more directly involved in body weight excess.

This manuscript addresses the Dial-A-Ride Problem (DARP) using Private Vehicles and Alternative Nodes (DARP-PV-AN). The DARP consists of creating vehicle routes in order to ensure a set of users’ transportation requests. Each request corresponds to a client needing to be transported from his/her origin to his/her destination. Routing costs have to be minimized while respecting a set of constraints like time windows and maximum route length.In the classical DARP, vehicles have to start from a depot and come back to it at the end of their route. In the DARP-PV-AN, the on-demand transportation service can be done either by a public fleet or by clients that use their private vehicles. The use of these vehicles adds more flexibility and unclog the public transportation fleet by allowing clients to organize their own transportation. However, it also raises some privacy concerns. The DARP-PV-AN addresses these concerns and focuses on location privacy, i.e. the ability to prevent third parties from learning clients’ locations, by keeping both original and final location private. This is addressed by setting several pickup/delivery nodes for the transportation requests, thus masking the private address.The DARP-PV-AN is first solved in a mono-objective context. A compact mixed integer linear model is presented and an Evolutionary Local Search (ELS) is proposed to compute solutions of good quality for the problem. These methods are benchmarked on a modified set of benchmark instances. A new set of realistic instances is also provided to test the ELS in a more realistic way. A second approach solving the mono-objective DARP-PV-AN is proposed. Based on a hybrid metaheuristic, it combines three methods: a genetic algorithm, a Branch and Bound method, and Integer Linear Programming (ILP) to solve the Weighted Set Cover Problem (WSCP). This approach is tested on the new instances and compared to the previously proposed ELS.This hybrid method is then tuned to solve the DARP-PV-AN in a bi-objective context. In order to do this, the multi-objective algorithm NSGA-II is used, always associated with a Branch and Bound method and bi-objective WSCP solving by ILP (Integer Linear Programming). For the bi-objective WSCP resolution, different aggregation methods were tested and compared. This approach is also tested on the new instances, modified to treat them in a bi-objective framework., Ce manuscrit aborde le problème du transport à la demande (Dial-A-Ride Problem – DARP) utilisant des véhicules privés et des sommets alternatifs (Dial-A-Ride Problem using Private Vehicles and Alternative Nodes – DARP-PV-AN). Le DARP consiste à créer des tournées de véhicules afin d’effectuer les transports de différents clients. Chaque requête correspond à un client ayant besoin d’être transporté de son point d’origine à son point de destination. Les différents coûts de transport doivent être minimisés tout en respectant un ensemble de contraintes comme les fenêtres de temps ou encore la durée maximale d’une tournée.Dans le DARP classique, les véhicules partent d’un dépôt et doivent y revenir à la fin de leur tournée. Dans le DARP-PV-AN proposé, le service de transport à la demande peut être assuré par les véhicules classiques (appelés véhicules publics) ou par les clients utilisant leurs propres véhicules (appelés véhicules privés). L’utilisation de ces véhicules ajoute plus de flexibilité et permet aux clients d’organiser leurs propres transports. Cependant, cela soulève également des problèmes de confidentialité. Le DARP-PV-AN propose également une solution à ces problèmes et met l’accent sur la confidentialité des adresses, c’est-à-dire la possibilité d’empêcher des tiers de connaître la localisation des clients en préservant leurs lieux de départ et d’arrivée. Pour cela, plusieurs sommets d’origine/destination sont ajoutés pour chaque demande de transport.Le DARP-PV-AN est tout d’abord traité dans un cadre mono-objectif. Un modèle linéaire est présenté et une métaheuristique de type ELS (Evolutionary Local Search) est proposée pour calculer des solutions de bonne qualité. Ces deux méthodes sont testées sur un ensemble d’instances classiques. Un nouvel ensemble d’instances dédiées au DARP-PV-AN est également fourni pour tester la méthode ELS.Une seconde approche de résolution du DARP-PV-AN mono-objectif est proposée. Basée sur une métaheuristique hybride, elle est divisée en trois parties. Un algorithme génétique est couplé à une méthode de « séparation et évaluation » (Branch and Bound) ainsi qu’à l’utilisation de la programmation linéaire en nombre entier (PLNE) pour résoudre le problème de couverture par ensembles avec poids (Weighted Set Cover Problem – WSCP). Cette approche est testée sur les nouvelles instances et est comparée à l’ELS proposé précédemment.Cette méthode hybride est ensuite adaptée pour résoudre le DARP-PV-AN dans un contexte bi-objectif. Pour cela, un algorithme génétique de type NSGA-II est utilisé. Ce dernier est associé à une méthode de Branch and Bound et à la résolution du WSCP bi-objectif par PLNE. Pour la résolution du WSCP bi-objectif, différentes méthodes d’agrégation ont été testées et comparées. Cette approche est également testée sur les nouvelles instances qui ont été modifiées pour les aborder dans un contexte bi-objectif.