Zetao Ma

Alain Bouscayrol

Walter Lhomme
email: walter.lhomme@univ-lille.fr

Keywords: Hybrid vehicle, urban delivery truck, multi-objective optimization, dynamic programming, electric variable transmission

niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Optimal sizing of the EVT for a hybrid urban delivery truck Zetao Ma * , * * Alain Bouscayrol * Walter Lhomme * Shumei Cui * *

INTRODUCTION

Electrification of vehicles have been proved to be of great potential for fuel saving and emission reduction [START_REF] Chan | The state of the art of electric, hybrid, and fuel cell vehicles[END_REF]; [START_REF] Emadi | Modern Electric, Hybrid Electric, and Fuel Cell Vehicles Fundamentals, Theory, and Design[END_REF]). However, truck manufacturers are reluctant to electrify their products due to two main reasons. One is that fuel saving scale is not very tempting if the truck spends most of its time on the highway. The other is that additional components such as energy buffers (batteries or supercapacitors) and electrical machines to electrify trucks may result in a huge surge of products prices. Nevertheless, [START_REF] Zirn | Hybridisation potentials for heavy trucks considering route topography[END_REF] proves that for those trucks which run in hilly terrain or urban areas, fuel savings are still promising. Also, the raised cost caused by additional components is not significant in the terms of total ownership, including operational costs and components cost, in life span. More importantly, trucks contribute greatly in greenhouse gas emission while the policy of emission restriction is becoming stricter and stricter, particularly for urban areas. Zero emission even is mandatory for specific city regions. Thus, electrification of delivery or distribution trucks is still of great interest.

Due to the low energy density and high cost of batteries, hybridization of the trucks appears to be a more suitable solution nowadays. Researchers and manufactures have worked on the hybrid electric vehicles (HEVs) for decades, offering many topology options for the conventional vehicles, for instance, series HEV, parallel HEV with continu-This work has been achieved within the framework of CE2I project (Intelligent Integrated Energy Converter). CE2I is co-financed by European Union with the financial support of European Regional Development Fund (ERDF), French State and the French Region of Hauts-de-France.

ous variable transmission or gear box and power split HEV with planetary gear set [START_REF] Emadi | Modern Electric, Hybrid Electric, and Fuel Cell Vehicles Fundamentals, Theory, and Design[END_REF]; [START_REF] Lhomme | Energy savings of a hybrid truck using a ravigneaux gear train[END_REF]; [START_REF] Mayet | Influence of a cvt on the fuel consumption of a parallel mediumduty electric hybrid truck[END_REF]), among which power split HEV is the most successful and efficient one. However, different from passenger vehicles, medium or heavy duty trucks have much higher torque demand which would bring low reliability and high maintenance to the planetary gear [START_REF] Lhomme | Energy savings of a hybrid truck using a ravigneaux gear train[END_REF]).

In this paper, an EVT is proposed for a hybrid medium duty truck. EVT is an energy conversion apparatus that can fully decouple the engine from the wheel speed in HEV application [START_REF] Hoeijmakers | The electric variable transmission[END_REF]). Researchers have been studied on this type of energy converter in the last decade ranging from machine or powertrain design, control and optimization [START_REF] Ahmed | Modeling and control of a novel power split hybrid electric vehicle[END_REF]; Cheng et al. (2011a,b); [START_REF] Druant | Torque analysis on a double rotor electrical variable transmission with hybrid excitation[END_REF]; [START_REF] Han | Electromagnetic analysis and design of switched reluctance double-rotor machine for hybrid electric vehicles[END_REF]; [START_REF] Zheng | Research on the cooling system of a 4QT prototype machine used for HEV[END_REF]). EVT-based HEV can achieve almost the same fuel saving as the Prius while no planetary gear set is required [START_REF] Vinot | Improvement of an EVTbased HEV using dynamic programming[END_REF]), which outstand its advantage for trucks.

This paper aims at optimal sizing of an EVT for a hybrid urban delivery truck, seeking the trade-off solutions in energy saving and the EVT size under certain drivability constraints. These constraints comprise maximal acceleration time from standstill to 100 km/h, top speed cruising, maximal grade-ability. To accurately size the EVT, proper design parameters are selected. Instead of sizing both EM1 and EM2 by changing their torque scales [START_REF] Vinot | Global optimized design of an electric variable transmission for hevs[END_REF]), EM1 is scaled by changing its speed and the EM2 is scaled by changing its torque.

The paper is organized as follows. The modelling of the EVT-based truck is presented in Section 2. The optimal sizing problem and a nested optimization method is described in Section 3. To benchmark the fuel economy of every feasible EVT size, in Section 4, the global minimal fuel consumption is obtained by a bi-level DP algorithm. In Section 5, Pareto front of the sizing results is presented.

MODELLING OF THE EVT-BASED TRUCK FOR EMS

Hybrid truck with EVT

The hybrid truck is for delivery mission in urban areas.

The UDDS driving cycle is used to evaluate its fuel economy. Major parameters of this truck is presented in Table 1. The other information of the truck and the UDDS cycle could be found in [START_REF] Hofman | Hybrid component specification optimization for a medium-duty hybrid electric truck[END_REF]. Final drive ratio 0.3

The powertrain (Fig. 1) is composed of an internal combustion engine (ICE), an EVT, its inverters and the battery pack. The EVT could be viewed as a compound of two machines, a double rotor machine denoted as EM1 and a stator machine denoted as EM2. The inner rotor of the double machine is connected to the ICE shaft. The outer rotor of EM1, which also is the rotor of EM2, is linked to the final drive to propel the wheels. With this configuration, the ICE is fully decoupled from the wheel speed, meaning that it could operates at its highly efficient region whatever the driving situation.

The EVT powertrain can operate in three different modes, pure electric mode, starter mode and hybrid mode. In the starter mode, EM1 drags the engine to above its idling speed before the ICE begins to work. Since neither clutch nor brake is utilized in the powertrain, only EM2 could be used in pure electric mode.

Principle of the EVT sizing

This paper aims to size an EVT of the delivery truck, which has already been hybridized with a parallel topology using a continuous variable transmission [START_REF] Mayet | Influence of a cvt on the fuel consumption of a parallel mediumduty electric hybrid truck[END_REF]). To highlight the interest of the EVT, the same truck is considered with an ICE of 90 kW and a battery of 15 kWh. The sizing only deals on the EVT keeping all other components.

It is well known that the fuel consumption of a hybrid vehicle is dependent on both the component sizing and the energy management strategy (EMS). EMS and sizing can thus not be independent. In this paper, the graphical formalism EMR (Energetic Macroscopic Representation) [START_REF] Bouscayrol | Graphic Formalisms for the Control of Multi-Physical Energetic Systems: COG and EMR[END_REF]) is used to organize the control of the system.

The EMR (Energetic Macroscopic Representation) of an EVT-based HEV has already been proposed [START_REF] Cheng | Specifications and design of a PM electric variable transmission for Toyota Prius II[END_REF]) (Fig. 2). As depicted in Fig. 2, the control is split in local control of subsystems when the EMS will deliver the torque and speed reference for the ICE (and its on/off activation). Such a model organization is too complex for developing EMS using optimal theory such as DP. Reduced model are thus proposed to reduce the computation time. Moreover a backward model is required for DP assuming that the local control is well achieved. This backward organization can be systematically derived from the EMR (Mayet et al. ( 2018)) (Fig. 3).

In the following subsection, only the reduced model is presented for the global sizing of the EVT and the development of the vehicle EMS. A more accurate model can be found in [START_REF] Cheng | Specifications and design of a PM electric variable transmission for Toyota Prius II[END_REF]).

Modeling details for the optimal EMS

The modelling of the EVT-based HEV powertrain for the backward searching is presented in this section.

1) Motion relation of the EVT powertrain:

The motion relation of the EVT powertrain in steady state can be described as

T e = -T 1 (1) T d = T 2 -T 1 (2) Ω 1 = Ω e -Ω 2 (3)
where Ω 1 ,Ω 2 and Ω e are the rotating speed of EM1, EM2 and ICE, T 1 and T 2 are the torques of EM1 and EM2, and T e is the engine torque, T d and Ω 2 are the equivalent demanded torque and rotating speed at the input side of the final drive shaft, which could be expressed as

T d = r k f η κ F d Ω 2 = k f v r (4) m dv dt = F d -F res (5)
F res = ρC d v 2 2 + mgf cos θ + mg sin θ + m dv dt (6)
where F d is the demanded tractive force, F res is the resistance force, r is the wheel radius, k f is the final drive ratio, ρ is the air density, C d is the drag coefficient, v is the vehicle velocity, m is the total vehicle mass, g is the gravity, θ is the road slope and κ is the coefficient determined by the torque direction, which can be expressed as

κ = 1, if F d v ≥ 0 -1, otherwise . (7)
2) Modelling of the engine and the electrical drives: Quasi-static modeling is used to model the engine and electrical drives.

The engine model in the backward searching can be represented by

 



Ω e = Ω eref T e = T eref ṁf = ψ e (Ω e , T e ) (8)
where Ω eref and T eref are the reference commands of the engine in the forward simulation (Fig. 2), ṁf is the fuel mass rate, ψ e is a three dimensional table for the brake specific fuel consumption map. Since in the backward searching, the engine inertia is neglected, it is considered that Ω e and T e equal to their reference all the time.

The electrical drives are depicted as power loss maps by

B 1 = ψ 1 (Ω 1 , T 1 ) i 1 = Ω1T1+B1 u b (9) B 2 = ψ 2 (Ω 2 , T 2 ) i 2 = Ω2T2+B2 u b (10)
where B 1 and B 2 are the power losses of the electrical drives respectively, ψ 1 and ψ 2 are the look-up table for the power losses, i 1 and i 2 are the currents of the electrical drives, u b is the battery voltage.

3) Battery modeling:

The battery pack is modeled as a open circuit model [START_REF] Emadi | Modern Electric, Hybrid Electric, and Fuel Cell Vehicles Fundamentals, Theory, and Design[END_REF]). The dynamics of the battery pack can be represented by

dSoC dt = -i b Q b P b = u b i b (11) i b = i 1 + i 2 u b = u oc -R b i b (12)
where SoC is its State-of-Charge, u oc , i b and R b are the open circuit voltage, battery current and internal resistance, Q b is the battery capacity, P b is the net output power of the battery.

The battery pack is used to absorb the electric power generated by the electrical machines or to provide additional power along with the engine to propel the powertrain. The power flow in the electric path should satisfy the balance relation:

P b = T 1 Ω 1 + B 1 + T 2 Ω 2 + B 2 . ( 13
)

OPTIMAL SIZING PROBLEM FORMULATION AND OPTIMIZATION METHOD

The multi-objective optimization problem is to search the optimal EVT size for the delivery truck while guaranteeing certain performances of drivability as below

   t acc ≤ 26 s v max ≥ 100 km/h θ max ≥ 9 % (14)
where t acc is the acceleration time from standstill to 100 km/h, v max is the highest velocity of the truck and θ max is the maximal slope that the truck can achieve when climbing at 15 km/h. It should be pointed out the engine size are fixed due to the performance of top speed cruising. In our case, a 90 kW engine is large enough to maintain the vehicle cruising at 100 km/h without the assistance of the battery. Also, the battery capacity is fixed to 15 kWh for 20 km pure electric driving range. Only the EVT size is investigated.

Sizing parameters of the EVT

Determining the specification of an electrical machine for vehicle traction requires many technical requirements, for instance, maximal speed, maximal torque and speed ratio (the maximum speed divided by the rated speed) [START_REF] Emadi | Modern Electric, Hybrid Electric, and Fuel Cell Vehicles Fundamentals, Theory, and Design[END_REF]). Especially, the difficulty increases since the efficiency map should be known on advance when evaluating the vehicle efficiency or fuel consumption. To reduce the complexity, we should choose proper design parameters for EM1 and EM2.

As depicted in Section 2, EM1 should balance the engine torque in steady state, which means that the maximal EM1 torque T 1max should be large enough to cover the maximal engine torque T emax of the selected engine. While for EM2, since its rotor is directly linked to the final drive, its maximal speed Ω 2max could be predetermined by the top speed requirement. These prerequisites are expressed by

T 1max = T emax Ω 2max = i f vmax r . ( 15
)
With these predetermined parameters, the remaining parameters to specify EM1 are its maximal speed and speed ratio. While for EM2, the remaining parameters are its maximal torque and speed ratio. For permanent magnets synchronous machine, the speed ratio could be chosen from 2.0 to 5.0, depending on its field weakening ability. To simplify the searching, the speed ratios of both EM1 and EM2 are fixed to a compromised value of 3.0, which is reasonable in machine design [START_REF] Han | Research on Modular Cascade Machines System for Electrical Vehicles[END_REF]). Now the left work is to determine the maximal speed for EM1 and the maximal torque for EM2. For consistency, we use the power rating to evaluate the machine size as

P 1max = T 1max Ω1max χ1 P 2max = T 2max Ω2max χ2 (16)
where P 1max and P 2max are the maximal power of EM1 and EM2, Ω 1max is the maximal EM1 speed, T 2max is the maximal EM2 torque, χ 1 and χ 2 are the machines speed ratios.

Due to the lack of data, most of the published papers utilize only one efficiency map to search the electrical machine size by multiplying a torque scale or speed scale [START_REF] Kim | Comprehensive design methodology of input-and output-split hybrid electric vehicles: In search of optimal configuration[END_REF]; Vinot et al. ( 2016)). To be more accurate, the program proposed in [START_REF] Han | Research on Modular Cascade Machines System for Electrical Vehicles[END_REF]) is used to generate the efficiency maps for different sizes of EM1 and EM2. The program has been proved to be quite accurate in the initial design of electric vehicles. In this program, only maximal torque, maximal speed and speed ratio are required for the approximation of machine efficiency. Utilizing this program, efficiency maps of different machines can be obtained.

Multi-objective sizing of the EVT

The sizing problem includes two objectives, one is to minimize the fuel consumption under the UDDS driving cycle while the other is to minimize the EVT size.

The cost function of the fuel consumption J f could be expressed by

J f = t f 0 ( ṁf (ω e , T e , x on ) + m e δ(u on )) dt ( 17
)
where t f is the total driving time on the cycle, u on is a control signal that turns the ICE on or off, m e is a constant that depicts the extra fuel consumption associated to the engine starting, and δ is the Dirac delta function

δ(u on ) = +∞, if u on = 1 0, otherwise. (18)
The relation between u on and the engine state is x + on = x on + u on (19) where x + on is the right time limit of x on , when x + on may jump to the other binary value, depending on u on .

The cost function of the EVT size J m is defined as the sum of the maximal power ratings of EM1 and EM2:

J m = P 1max + P 1max .

(20) With the different cost functions, the multi-objective sizing problem can be summarized as min J f , J m subject to:

t acc ≤ 26 s v max ≥ 100 km/h θ max ≥ 9 % (21)

Optimization method

In the optimal sizing problem ( 21), the objective is to find the minimal EVT size and the best fuel economy while guaranteeing the drivability performances. A nested optimization method is applied to exhaustively search the EVT size. Firstly, for every machine combination in the EM1 set and EM2 set, the minimal acceleration time, top speed and maximal grade-ability are verified. To obtain the minimal acceleration time, DP could be applied into the acceleration process, [START_REF] Kim | Comprehensive design methodology of input-and output-split hybrid electric vehicles: In search of optimal configuration[END_REF]. For the top speed cruising and grade-ability, the verification can be built by static searching. Machine combinations do not satisfy these basic requirements are discarded. For those feasible machine combinations, the fuel consumption is further evaluated by the proposed DP algorithm in Section 4. After the exhaustive searching, the Pareto front of the J f and J m can be depicted.

BI-LEVEL DP ALGORITHM FOR EMS

To evaluate the fuel economy of each selected EVT size, DP is used to benchmark the global minimal fuel consumption. However, DP would bring huge computation burden when exhaustive searching is applied to find the Pareto front. To reduce the computation time, a bi-level DP algorithm is formulated in this section.

The optimization problem of energy management for the EVT powertrain under charge-sustaining condition can be summarized as min J f (Ω e , T e , u on , x on ) subject to: (1) -(13)

x on (0) = 0, SoC(t 0 ) = SoC(t f )

x on ∈ {0, 1}, u on ∈ {-1, 0, 1} i b ∈ [i bmin , i bmax ], SoC ∈ [SoC min , SoC max ] T e ∈ x on [T emin (Ω e ), T emax (Ω e )], Ω e ∈ [Ω emin , Ω emax ] T 1 ∈ [T 1min (Ω 1 ), T 1max (Ω 1 )], Ω 1 ∈ [Ω 1min , Ω 1max ] T 2 ∈ [T 2min (Ω 2 ), T 2max (Ω 2 )], Ω 2 ∈ [Ω 2min , Ω 2max ] (22)
In the optimization problem ( 22), there are two independent continuous control signals including T e and Ω e , one discrete control signal u on and two states x on and SoC.

To solve this mix-integer problem, backward searching, also known as DP [START_REF] Bellman | Dynamic Programming[END_REF], is utilized under the assumption that the driving cycle is known on advance. DP has been widely used in the global optimization of the hybrid electric vehicles for different topics [START_REF] Kim | Comprehensive design methodology of input-and output-split hybrid electric vehicles: In search of optimal configuration[END_REF]; [START_REF] Maamria | On the use of dynamic programming in eco-driving cycle computation for electric vehicles[END_REF]). However, it requires huge computation effort to solve this optimization problem due to its large scale of complexity. To reduce the computation burden of the DP search, the optimal energy management is formulated as a bi-level algorithm.

Firstly, substitute (1)-( 3) into (13), the electric power can be written as

T d Ω 2 -P b = T e Ω e -B 1 (T e , Ω e ) -B 2 (T d -T e , Ω 2 ) (23)
Then, a variable change P c is introduced to replace T e as the control variable:

P c (T e , Ω e ) = T e Ω e -B 1 (T e , Ω e -Ω 2 ) -B 2 (T d -T e , Ω 2 ) (24)
While the power balance of the hybrid powertrain can be derived as T d Ω 2 = P b + P c (25) With this formulation, the ICE, EM1 and EM2 are considered as a compound unit whose net output power P c propels the powertrain together with the battery. Then the optimization problem in ( 22) could be reformulated as min J f (P c , u on , x on ) subject to: (11)

x on (0) = 0

x on ∈ {0, 1} u on ∈ {-1, 0, 1} SoC(t 0 ) = SoC(t f ) i b ∈ [i bmin , i bmax ] SoC ∈ [SoC min , SoC max ] P d = P c + P b P c ∈ [P cmin (T d , Ω 2 ), P cmax (T d , Ω 2 )]. ( 26
)
Since the driving cycle is known on advance, for given Ω 2 and T d , the optimum mapping from P c to ṁf could be obtained before the DP begins. While during the DP searching, the fuel consumption from one SoC node to another could be directly obtained by interpolation of the optimal P c ∼ ṁf map, leaving P c as the only continuous control signal.

OPTIMAL SIZING OF THE EVT FOR THE DELIVERY TRUCK

Feasible sets of the design space

Before the Pareto design, the feasible set of the EVT size should be found to meet the requirement of performance constraints in ( 14). The feasible sets determined by the performance constraints are presented in Fig. 4-Fig. 6 respectively, which are denoted as shaded regions. From Fig. 4-6, it could seen that both EM1 and EM2 have influence on the acceleration performance, top speed and grade-ability. The influence of EM1 on the powertrain comes from its connection to the engine. As depicted in Section 2, EM1 is used to delivery the engine torque in hybrid mode. Once EM1 limits the engine output, the powertrain drivability will also be affected. EM2 has a more significant impact on the drivability, due to its direct linking to the final drive.

Finally, the feasible space for Pareto design could be depicted as intersection of feasible sets acquired from different performance constraints, as shown in the shaded region in Fig. 7.

NYTruck ZeroEmission

Fuel economy of the delivery truck

The fuel consumption of the delivery truck under the UDDS driving cycle over the feasible set is presented in Fig. 8, through DP. In the feasible set, the minimal fuel consumption is about 16.85 L/100km. The fuel economy of the delivery truck could be improved by 21.63 % compared to the conventional truck with a gear box. It could be seen that hybrid delivery truck with EVT can provide considerable fuel saving.

Pareto front of the EVT size and the fuel consumption

The pareto front [START_REF] Miettinen | Nonlinear Multiobjective Optimization[END_REF]) of the EVT size and the fuel consumption are depicted in Fig. 9. It could be seen that the minimal fuel consumption could be obtained when the EVT power rating reaches around 159 kW. At this point, the EM1 power rating is about 60kW and the EM2 power rating is about 98.5kW. Also, in the terms of fuel economy, a larger EVT size may increase the fuel consumption. Since the fuel consumption difference between the minimal power rating point and the minimal fuel consumption point is quite small (only 0.3 %), the smallest EVT size could be even considered for the delivery truck. This paper presents the optimal sizing of EVT for the hybrid delivery truck. The optimal sizing problem is formulated and solved by exhaustive searching. A bi-level DP method is developed to optimize the fuel consumption under UDDS driving cycle for fair comparison and benchmark. Simulation results show that promising fuel saving potential (21 % reduction) could be expected when using an EVT to the delivery truck. Also, for the truck application under UDDS driving cycle, a minimal EVT size could be chosen as long as it could satisfy the performance requirement since its fuel saving is already closed to the best potential.

Fig. 1 .

 1 Fig. 1. Archtitecture of the studied EVT-based HEV.

Fig. 2 .Fig. 3 .

 23 Fig. 2. EMR and control scheme of the EVT-based HEV.

Fig. 4 .Fig. 5 .

 45 Fig. 4. Feasible EVT size for acceleration performance.NYTruck ZeroEmission

Fig. 7 .

 7 Fig. 6. Feasible EVT size for grade-ability.

Fig. 8 .

 8 Fig. 8. Fuel consumption under UDDS truck cycle over the feasible design space

Fig. 9 .

 9 Fig. 9. Pareto front of the sizing and the fuel consumption

Table 1 .

 1 Truck parameters

	Parameter	Value
	Total mass	7258 kg
	Frontal area	6.9 m 2
	Wheel radius	0.397 m
	Inertia of rotating parts 20 kgm 2


A Pam

Alain Bouscayrol
email: alain.bouscayrol@univ-lille.fr

P Fiani

F Faval

P Barrade

Integration of the Road Slope in the Optimization of the Energy Management Strategy of a parallel HEV

Keywords: Road slope, Optimization, Energy Management Strategy, Hybrid Electric Vehicle I EMR PICTOGRAMS

Optimization methods for Energy Management Strategy (EMS) are more and more used to minimize the fuel consumption of Hybrid Electric Vehicles (HEV). For off-line techniques, such as dynamic programming, from a given driving cycle, an algorithm is defined to determine the optimal power flows of the vehicle. Most of the time, the optimization is achieved by not considering the resistive force due to the road slope, which can be very high in certain roads depending on the mass of the vehicle. This paper aims to quantify the accurate fuel consumption economy when the road slope is integrated or not in the EMS optimization problem of a parallel HEV using dynamic programming.

INTRODUCTION

The world mobility continues struggling with some economic and environmental threats (IEA, 2015). Electric vehicles are certainly a promising solution for mobility improvement. Unfortunately, the low autonomy and the long charging time of their batteries are major constraints. Hybrid electric vehicles (HEV) are more and more used to avoid those constraints [START_REF] Chan | Electric, Hybrid and Fuel Cell Vehicles: Architectures and Modeling[END_REF].

In the development phase of HEVs, simulation is an important step. Indeed, control schemes and Energy Management Strategies (EMS) are developed and validated using physical models [START_REF] Guzzella | Supervisory Control Algorithms[END_REF]. According to the objective of the simulation or the study, assumptions are made in the modelling to allow fast testing [START_REF] Gao | Modeling and Simulation of Electric and Hybrid Vehicles[END_REF] [START_REF] Chan | Electric, Hybrid and Fuel Cell Vehicles: Architectures and Modeling[END_REF] (Aziz et al., 2011) [START_REF] Denis | Power Split Strategy Optimization of a Plug-in Parallel Hybrid Electric Vehicle[END_REF]. For the EMS development of HEV, the resistive force due to road slope is rarely considered. However, it might lead to some error on the fuel consumption estimation, especially if the vehicle mass is important. Indeed, the force due to the road slope, called also gradient force, depends on the slope, the mass of the vehicle and the gravity [START_REF] Ehsani | Modern Electric, Hybrid Electric, and Fuel Cell Vehicles[END_REF]. Then, if the road slope is important, the required traction power can be large. In fact, most of the time, the road slope is neglected because of the lack of parameters on the used driving cycles. For example, standard driving cycles such as NEDC or WLTC do not consider any slope. Techniques have even been developed to determine the road slope [START_REF] Bae | Road Grad and Vehicle Parameter Estimation for Longitudinal Control using GPS[END_REF] (Hellstrom et al., 2007) [START_REF] Mangan | Development of a Novel Sensorless Longitudinal Road Gradient Estimation Method Based on Vehicle CAN Bus Data[END_REF] [START_REF] Sebsadji | Road Slope and Vehicle Dynamics Estimation[END_REF] [START_REF] Sahlholm | Road Grade Estimation for Look-ahead Vehicle Control using Multiple Measurement Runs[END_REF]. This estimation is mainly used to determine the gradeability of the vehicle in function of the vehicle mass and the gearbox ratio [START_REF] Yamsani | Gradeability for Automobiles[END_REF]. This paper aims to quantify the effective fuel consumption of a plug-in parallel HEV when the resistive force due to the road slope is considered or not. In that aims, dynamic programming (DP) is used to solve the optimization problem of the EMS of the vehicle. For the EMS optimization, a backward approach is used for the vehicle model. A forward model of the vehicle, organized by the Energetic Macroscopic Representation (EMR) (Bouscayrol et al., 2000) [START_REF] Bouscayrol | Graphic Formalism for the Control of Energetic Multiphysics Systems[END_REF] will help in validating the optimal EMS. Section II presents the organization of the complete forward model and control scheme of the studied vehicle thanks to EMR. In Section III, the road slope is not considered for the identification of an optimal EMS. In Section IV, an optimized EMS considering the road slope is achieved using dynamic programming and validated on the forward model.

II. GLOBAL MODELLING AND CONTROL OF THE STUDIED VEHICLE

A. EMR of the studied Vehicle

The studied vehicle is a plug-in parallel hybrid powertrain composed of an ICE of 43 kW and an electric drive of 20 kW with a li-ion battery (Figure 1). The vehicle weight is 1.3 t. [START_REF] Johnson | Battery Performance models in ADVISOR[END_REF].

𝑣 𝑏𝑎𝑡 = 𝑉 𝑐𝑜 (𝑆𝑜𝐶) -𝑅 𝑏𝑎𝑡 (𝑆𝑜𝐶)𝑖 𝑏𝑎𝑡 (1)
Electric drive -The electric drive is composed of a voltage source inverter and an induction machine. A dynamic model could be developed. But, in a macroscopic study for EMS identification, a comparison between the dynamic model of the electric drive and a static model based on its efficiency map shows less than 1% error in the energy consumption (Letrouvé et al., 2010). By using the efficiency map for the electric drive, the torque of the induction machine is then determined (2). where 𝑘 = { 1 𝑓𝑜𝑟 𝑃 𝑏𝑙𝑡 ≥ 0 -1 𝑓𝑜𝑟 𝑃 𝑏𝑙𝑡 < 0

The complex structure of the clutch makes its model too difficult to achieve. Moreover, when comparing a study with clutch to a study without clutch, the energy impact is very low (1%) due to its short time use (Letrouvé et al., 2009). An ideal clutch is thus considered in this study. Considering that the vehicle moves on a straight line, an equivalent wheel is used for the model. So, the clutch, the gearbox, the differential and the wheels, can be considered as one mechanical power converter which converts a rotational movement to a linear movement. The wheel force, Fwh, is obtained with the beltpulley torque and the equivalent ratio and efficiency of the mechanical power converter, kmt and ηmt. The same logic is used for the speeds, to determine the speed in the machines side of the clutch, Ωclu, with the vehicle velocity, vveh. The aims of the control of the vehicle is to deliver the right tuning input to the system in order to achieve a given objective, which is the vehicle velocity. The inversion of the EMR leads to the control scheme. To build the control scheme, each relationship type in the model is inverted. According to EMR rules, if the relationship in the model has no delay, the inversion is directly achieved. But, if the relationship yields a delay, then, a closed-loop control is needed in the inversion. By the inversion of the EMR, the control scheme of the plug-

ED Battery ICE GB Ω blt T blt F wh k mt Ω em T em T ice_ref Ω ice T ice ICE F res v veh v veh Road v bat i bat Bat T em_ref T blt_ref F wh_ref v veh_ref T ice_ref F env v veh Road V veh_mea SoC F wh (2) (1) (4) (3) (6) (7) (5) Model Local Control Electric Drive Mechanical Transmission Chassis (9)
in parallel HEV is deduced (Figure 2). Estimations are made for non-measurable variables like Fres.

For the EMS study, this paper is focused on the power flow distribution between the electric drive and the ICE (9). So, it is assumed that the braking is fully electric. The EMS delivers the requested torque of the ICE.

𝑇 𝑒𝑚_𝑟𝑒𝑓 = 1 𝑘 𝑏𝑙𝑡 (𝑇 𝑏𝑙𝑡_𝑟𝑒𝑓 -𝑇 𝑖𝑐𝑒_𝑟𝑒𝑓 ) (9)

III. OPTIMAL EMS OF THE VEHICLE NEGLECTING THE ROAD SLOPE

A. Backward Model for Dynamic Programming Dynamic programming (DP) is widely used to determine the optimum behaviour of a system [START_REF] Guzzella | Vehicle propulsion systems, introduction to modelling and optimization[END_REF]. However, future events must be known in advance in order to determine the optimum. This makes the dynamic programming unusable in real time, in the context of parallel HEV where future constraints applied to the vehicle by the environment are difficult to be predicted. Nevertheless, it allows to obtain a theoretical optimum. So, its result can be a benchmark for other real-time usable methods.

The principle developed in this contribution is then to identify an optimal behaviour of the parallel HEV using a backward modelling approach where future events can be taken into account. In the second step, the optimized EMS is tested on forward-based model such as that one presented in Figure 2 for tests and pre-validation of results in a real-time configuration.

Then, in order to use DP for determining an optimized EMS, a "backward" model is required. EMR can be easily converted into a backward model [START_REF] Mayet | Comparison of different models and simulation approaches for the energetic study of a subway[END_REF]. This "backward" model is based on equation (10). It is a model simplification as the control is now considered ideal. The total traction force is calculated based on the velocity of the vehicle, the acceleration, the resistive force. The "backward" model of the plug-in parallel HEV can be deduced from EMR (Figure 3). Optimization by dynamic programming is based on the principle of optimality of Bellman [START_REF] Bellman | Dynamic Programming[END_REF]. The principle is to divide the problem in locally optimized subproblems which will lead to an overall optimization of the system.

B. Optimal EMS neglecting the road slope

The goal is there to minimize the ICE fuel consumption. The minimal consumption is the sum of the minimal consumptions between two operating points of the ICE. The cost function is defined as the fuel consumption. The equation that solves the optimization problem of this cost function is given (11). To solve this matter for minimizing the cost function, constraints are set on the SoC of the battery and the distribution coefficient (12). The cost function and the defined constraints allow to calculate the optimal SoC of the battery that gives the minimal cost for each point of the driving cycle. The ideal evolution of the SoC is then calculated to achieve the minimum of the fuel consumption. Based on this approach, the optimized EMS using DP is determined (Figure 4). It defines the optimal requested torque of the ICE.

𝐽 * = 𝑚𝑖𝑛(𝐽) = ∑ 𝐿 (𝑆𝑜𝐶(𝑖), 𝑇 𝑖𝑐𝑒_𝑟𝑒𝑓 (𝑖)) . ∆ 𝑁-1 𝑖=0 (11)
where: J, the cost function is the fuel Consumption. L is the lowest cost function between two samples (fuel flow). i, is the actual point on the driving cycle, and, Δ as an illustration.

{ 𝑆𝑜𝐶 𝑚𝑖𝑛 ≤ 𝑆𝑜𝐶(𝑖) ≤ 𝑆𝑜𝐶 𝑚𝑎𝑥 𝑆𝑜𝐶(𝑖 𝑒𝑛𝑑 ) = 𝑆𝑜𝐶(𝑖 𝑠𝑡𝑎𝑟𝑡 ) 𝑇 𝑖𝑐𝑒 ̌≤ 𝑇 𝑖𝑐𝑒_𝑟𝑒𝑓 (𝑖) ≤ 𝑇 𝑖𝑐𝑒 ̂ (12)
The road slope is a parameter that is difficult to determine. Generally, most of the time it is not considered for the EMS optimization. This EMS is determined neglecting the rod slope. The results of the DP-EMS with the backward model gives a fuel consumption around the 3.99L/ 100 km (Figure 6). The constraints on the battery SoC are well respected. The DP-EMS determined without road slope is applied to the forward model considering the road slope for the evaluation of the real performances of the obtained DP-EMS in a more realistic simulation approach. Comparative results are presented in Figure 7.

The fuel consumption is increased up to 9% when the DP-EMS is applied to the forward model (with road slope) compared to the backward model. In fact, because the road slope is considered in the forward model, the traction power increases in some parts of the cycle, and the optimality, which was defined by the DP without the road slope, cannot be respected anymore. The consequence is that the ICE does not operate in its optimal areas. The fuel consumption is thus higher than expected.

Figure 7: Results for DP-EMS (no road slope)

The physical limitations on the system has a big effect on the fuel consumption (Figure 8). In fact, a zoom in the torques of the ICE and the induction machine shows that, in some areas, in the backward model (without road slope), the ICE was used to charge the battery while powering the vehicle. But, in the forward model (with road slope), because of the increase of the traction power, the ICE is requested to deliver more power. Even, in some areas, the power delivered by the ICE is not sufficient to power the vehicle at that speed, because of its physical limitations. The battery is then used to supply the rest of the traction power. This causes the increase of the fuel consumption and the depletion of the SoC of the battery. In this section, the road slope is considered for the EMS development. Based on the same approach, the optimized EMS using DP with the road slop is determined (Figure 9). It determines the requested torque of the ICE. The simulations are made through the same real-life driving cycle (Figure 5). But in this case the road slope is considered. The velocity of the vehicle, the elevation, the road slope and the evolution of Fslop, in function of the distance are presented by Figure 10. The DP-EMS with road slope is run with the forward model and compared to the results with the backward model (Figure 11).

The reference velocity is well achieved. In terms of fuel consumption, overall, the difference is less than 1%. It is related to the difference between the forward modelling approach and the backward. In fact, in the backward modelling approach, the control is assumed ideal. But in the forward model, a closed-loop control is developed to assure the tracking of the reference vehicle velocity. However, the constraints on the SoC of the battery are respected. That indicates that the model reduction with the backward organization does not lead to an important error. The effect of the road slope is quite obvious on the fuel consumption (TABLE I). Furthermore, when neglected in the optimization of the EMS, if the defined EMS is applied on the model with road slope, the fuel consumption increases up to 9%. That percentage represents the error that is made in the model by not considering the road slope. In fact, when the road slope is considered in the optimization of the EMS, there is no error on the model.

It is better then, to consider the road slope in the optimization problem in order to keep the optimality of the system.

V. CONCLUSION

Two different models of a plug-in parallel HEV has been studied for the optimization of the EMS. They are based on consideration or not of the road slope of a real-life driving cycle. Dynamic programming has been used for the optimization of the EMS with two backward models considering or not the road slope. Each EMS algorithm has been applied to the forward model considering the road slope as in the real case. There is no error on the model when the road slope is considered in the EMS optimization. But the error is 9% when the road slope is not considered in the EMS optimization. Furthermore, when the road slope is considered, the EMS can assure of the optimality of the system. So, in the case of high gradients for important mass vehicles, it is better to considered the road slope for the EMS studies and optimization in order to avoid unreliable results.

Figure 1 :

 1 Figure 1: plug-in parallel HEV structure Battery -The battery is considered as voltage source, Vbat, composed of an open circuit voltage, Voc, in series with an internal resistance, Rbat, in function of the battery State-of-Charge (SoC) and the current, ibat[START_REF] Johnson | Battery Performance models in ADVISOR[END_REF].

  with: k = -𝑠𝑖𝑔𝑛(𝑇 𝑒𝑚 Ω 𝑒𝑚 )(2)Internal combustion engine (ICE) -The ICE is considered as a mechanical controlled torque source. A static model (isoconsumption map), which delivers the ICE torque, Tice, in function of a reference torque, Tice-ref, is developed.𝑇 𝑖𝑐𝑒 = 𝑇 𝑖𝑐𝑒_𝑟𝑒𝑓 (3)Mechanical transmission -The mechanical transmission is composed of a belt-pulley coupling, a clutch, a gearbox with five gear ratios, a differential, the wheels, and the chassis of the vehicle. The belt-pulley output torque, Tblt, is obtained by the sum of the torques of both the induction machine and the ICE, in function of the ratio, kblt, and the efficiency, ηblt. The ICE speed is the same as the input speed of the clutch, Ωclu.{ 𝑇 𝑏𝑙𝑡 = 𝜂 𝑏𝑙𝑡 𝑘 (𝑘 𝑏𝑙𝑡 𝑇 𝑒𝑚 + 𝑇 𝑖𝑐𝑒 ) Ω 𝑒𝑚 = 𝑘 𝑏𝑙𝑡 Ω 𝑐𝑙𝑢 (4)

  the vehicle determines the vehicle motion by its mass. So, the vehicle velocity, vveh, is determined by using the dynamic relationship of a mass in translating movement. The road of the vehicle characterizes the equivalent resistive force, Fres, to the vehicle motion. The equivalent resistive force is composed of the rolling force, Frol, the aerodynamic force, Faero, and the force due to the road slope, Fslop. The lather depends on the mass of the vehicle, the gravity, 𝑔, and the slope (8).𝐹 𝑟𝑒𝑠 = 𝐹 𝑎𝑒𝑟𝑜 + 𝐹 𝑟𝑜𝑙 + 𝐹 𝑠𝑙𝑜𝑝(7) where: 𝐹 𝑠𝑙𝑜𝑝 = 𝑀 𝑣𝑒ℎ 𝑔(sin 𝛼) with α, the road slope (8)EMR is a graphical formalism used to organize models of complex systems. Energy sources are depicted by green pictograms, energy storages by crossed orange rectangles, energy converters by orange squares or circles and energy distribution elements by overlapped squares (see appendix). The complete EMR of the vehicle is presented by Figure 2 (Pam et al., 2017).

Figure 2 :

 2 Figure 2: EMR and control of the plug-in parallel HEV

Figure 3 :

 3 Figure 3: Backward EMR-based model of the parallel HEV

Figure 4 :

 4 Figure 4: DP-EMS calculation (no road slope)Some simulations have been made through a real driving cycle covering a distance of 188 km in "Canton de Vaud / Switzerland" from Lausanne and back (Figure5).

Figure 5 :

 5 Figure 5: Travelling map in "Canton de Vaud / Switzerland"

Figure 6 :

 6 Figure 6: Results of DP-EMS without road slope C. Validation on the vehicle forward model

Figure 8 :

 8 Figure 8: Analysis of the physical limitations IV. OPTIMAL EMS OF THE VEHICLE INTEGRATING THE ROAD SLOPE A. Optimal EMS integrating the Road Slope

Figure 9 :

 9 Figure 9: DP-EMS calculation (with road slope)

Figure 10 :

 10 Figure 10: Real-life Driving cycle in "Switzerland"

Figure 11 :

 11 Figure 11: Results for DP-EMS (with road slope)

ACKNOWLEDGMENT

  This paper was written in the goal of a PhD thesis. The authors would like to gratefully thank the ANRT (French agency of technologic research) for its financial support and the French network on HEVs: MEGEVH. REFERENCES A. Aziz, M. S. Shafqat, M. A. Qureshi, I. Ahmad, 2011. "Performance Analysis of Power Split Hybrid Electric Vehicles using Autonomie". IEEE -Stud. Conf. on Research and Development, December 2011. A. Bouscayrol, B. Davat, B. de Fornel, B. François, J. P. Hautier, F. Meibody-Tabar, M. Pietrzak-David, 2000. "Multimachine Multiconverter System: application for electromechanical drives", European Physics Journal -Applied Physics, vol. 10, no. 2, pp. 131-147, May 2000.

TABLE I .

 I Fuel consumption comparison

		DP-EMS	DP-EMS
		(no road slope)	(with road slope)
	Backward model	3,99 L / 100 km	4,01 L / 100 km
	Forward model	4,35 L / 100 km	4,03 L / 100 km
	Error	9 %	0,4 %


Anne Freyens
email: anne.freyens@dumg-toulouse.fr0672056666

Marion Monti
email: marion_m_94@hotmail.com

Lauriane Vignocan
email: vignocan.lauriane@neuf.fr

Pierre Mesthe
email: pierre.mesthe@dumg-toulouse.fr

Femmes victimes de violences sexuelles : attitudes attendues de la part de leur médecin Women Victimes of Sexual Violence : attitudes expected from their doctor

Keywords: Sexual violence, general medicine, women, expectations, medical consultation, guidelines

Background: In France, 20.4% of women report having experienced at least one form of sexual violence in their lifetime. (ONDRP, INSEE. Living environment and security). Of these, 26% saw a doctor following this incident and 8% told them about it. (Inserm, Ined, ANRS. Context of sexuality in France. 2006). Objective: In view of this high prevalence, it seemed important to explore the expectations of these women during a general medical consultation in order to improve their care. Method: This qualitative study was conducted through semi-structured individual interviews conducted between April and December 2015. The interviews were conducted with 14 adult women who had experienced sexual violence. They were between 19 and 50 years of age and had varied socio-epidemiological profiles. Results: The general practitioner was perceived as a primary care professional for them, and they expected mainly from him/her: a non-judgmental listening, a referral to psychologists and specialized associations, as well as certain precautions during the clinical examination. The women wanted him/her to be trained to deal with sexual violence. It would be necessary for the general practitioner to be able to recognize the evocative signs and to be trained in the physical and psychological consequences of sexual violence. Conclusion: At first glance, caring for a patient who is a victim of sexual violence may seem complex to the doctor. But according to the women, it only takes a short time for their general practitioner to be helpful.

Résumé

Patients et méthodes

Recrutement

Des femmes volontaires pour partager leur vécu ont été recrutées par les voies suivantes :

• Création d'une adresse mail commune, afin de communiquer avec tous les intervenants de ce travail de recherche (associations, femmes, directeurs de thèse).

• Contact avec des associations (Annexe 4) et avec des cabinets médicaux pour un affichage au sein de leurs locaux ou sur leurs portails Web (Annexe 5).

• Extension à des réseaux sociaux ainsi que des adresses mails et des contacts personnels.

Les critères d'inclusion retenus pour les entretiens étaient : le genre féminin, un âge supérieur à 18 ans, avoir été victime de violences sexuelles et être volontaire pour participer à l'étude. Nous avons retenu 14 volontaires en adéquation avec tous les critères inclusifs cités ci-dessus, et qui ont accepté de remplir une fiche de renseignement socio-épidémiologiques. Ce groupe comportait une variété de statuts conjugaux, relationnels et de professions : 6 célibataires, 5 séparées ou divorcées, 3 mariées ou en couple ; 5 étudiantes, une femme sans profession, 2 enseignantes, une manager en informatique, une gardienne d'enfants, une chercheuse en physique, une agent administrative, une artiste et une auxiliaire de vie. Leur niveau d'étude allait de l'absence de diplôme au doctorat. Elles étaient toutes de nationalité française dont une La saturation théorique des données (Glaser & Strauss,1967) « le point de saturation théorique est atteint lorsque, de la collecte des données, n'émerge plus rien de vraiment nouveau ni de vraiment consistant ») a marqué la fin de la réalisation des entretiens, un entretien supplémentaire a été réalisé pour confirmer la saturation.

14 entretiens ont été réalisés, d'une durée de 48 minutes en moyenne. L'entretien le plus court a duré 9 minutes contre 2h25 pour le plus long (selon la capacité à s'exprimer plus ou moins facilement sur le sujet).

Les résultats

Les attentes des femmes : être écoutées, orientées, accompagnées

Concernant leur santé, les femmes décrivaient pour la plupart des symptômes physiques dont des troubles ostéo-articulaires « Le matin je peux pas me lever, je tombe par terre, j'ai plus de jambes, j'ai les poignets et les pieds qui font comme ça… » -Laurie ; des pathologies gynécologiques ou des douleurs abdominales

Discussion

Les résultats qui corroborent d'autres études

Concernant les profils des femmes, elles avaient des âges différents, avec des niveaux socio-économiques variés et ayant tous types de profession, ce qui correspond aux donnés socio-épidémiologiques retrouvées dans la littérature (Leroy [START_REF] Sharma | Prise en charge des violences sexuelles en Médecine Générale : étude qualitative auprès de 17 médecins généralistes[END_REF] [START_REF] Ait Boughima | Les violences sexuelles intraconjugales (étude descriptive de 28 cas)[END_REF]. Les symptômes à la fois psychologiques et physiques présentés par les femmes de ce travail étaient proches de ceux évoqués dans d'autres études : douleurs abdominales, gynécologiques, ostéo-articulaires, syndromes anxieux ou dépressifs, troubles du sommeil ou du comportement alimentaire, troubles sexuels… (Guillet-May and Thiebaugeorges, 2006) [START_REF] Campbell | Health consequences of intimate partner violence[END_REF] [START_REF] Sharma | Prise en charge des violences sexuelles en Médecine Générale : étude qualitative auprès de 17 médecins généralistes[END_REF] [START_REF] Gamet | Violences sexuelles des mineurs en France : comment les médecins peuvent devenir des interlocuteurs privilégiés des victimes ?[END_REF] [START_REF] Coles | General practice service use and satisfaction among female survivors of childhood sexual abuse[END_REF]) [START_REF] Lacambre | Clinique et prise en charge des Auteurs de Violences Sexuelles[END_REF]. La prise en charge des femmes victimes de violences sexuelles a été reconnue comme étant du ressort du médecin généraliste, notion retrouvée également dans de nombreux écrits (Friedman et al., 1992) (Palisse, n.d.) Les attentes principales des femmes étaient conformes à celles présentes dans la littérature : les écouter sans jugement, les orienter vers des associations ou des aides psychologiques et les accompagner en les encourageant à faire valoir leurs droits [START_REF] Nguyen | sexuelles faites aux femmes : le point de vue des patientes[END_REF] [START_REF] Lacambre | Clinique et prise en charge des Auteurs de Violences Sexuelles[END_REF]. Les violences sexuelles sont une source de syndrome de stress post-traumatique [START_REF] Louville | Clinique du psychotraumatisme[END_REF] [START_REF] Breslau | Traumatic events and posttraumatic stress disorder in an urban population of young adults[END_REF] avec des conséquences sur le vécu au quotidien, de l'image de soi, du déshabillage, de l'examen médical, de la vie sexuelle… d'où l'importance d'un soutien psychologique et d'un accompagnement adapté [START_REF] Bisson | Psychological therapies for chronic post-traumatic stress disorder (PTSD) in adults[END_REF]. Les femmes ont abordé également le caractère trop onéreux des psychothérapies qui pouvait être un frein à leur prise en charge.

A propos du dépistage systématique des violences sexuelles en consultation :

Les résultats de l'étude étaient plus mitigés que ceux de la littérature concernant le caractère systématique du dépistage des violences sexuelles en consultation de médecine générale. Les travaux déjà effectués montrent un retour plus positif des patients à ce propos [START_REF] Friedman | Inquiry about victimization experiences. A survey of patient preferences and physician practices[END_REF] [START_REF] Thombs | A brief two-item screener for detecting a history of physical or sexual abuse in childhood[END_REF] [START_REF] Coid | Sexual violence against adult women primary care attenders in east London[END_REF].

De nombreuses femmes de notre étude pensaient que la réalisation de ce dépistage dépendait du motif de consultation et de la relation entre elles et le médecin.

A propos de la formation spécifique :

La formation des médecins aux violences sexuelles était une attente des femmes. En

  Contexte : En France, 20,4% des femmes déclarent avoir subi au moins une forme de violences sexuelles au cours de leur vie. (ONDRP, INSEE. Cadre de vie et sécurité). Parmi elles, 26% ont vu un médecin suite à cet incident et 8% lui en ont parlé. (Inserm, Ined, ANRS. Contexte de la sexualité en France. 2006). Objectif : Devant cette forte prévalence, il semblait important d'explorer les attentes de ces femmes lors d'une consultation de médecine générale afin d'améliorer leur prise en charge. Méthode : Cette étude qualitative a été réalisée grâce à des entretiens semidirigés individuels menés entre avril et décembre 2015. Les entretiens ont été réalisés auprès de 14 femmes majeures ayant vécu des violences sexuelles. Elles étaient âgées de 19 à 50 ans et avaient des profils socio-épidémiologiques variés. Résultats : Le médecin généraliste était perçu comme un professionnel de premier recours pour elles, et elles attendaient principalement de sa part : une écoute sans jugement, une orientation notamment vers des psychologues et des associations spécialisées ainsi que certaines précautions lors de l'examen clinique. Les femmes souhaitaient qu'il soit formé à la prise en charges des violences sexuelles. Il serait nécessaire pour le médecin généraliste de savoir reconnaître les signes évocateurs et d'être formé aux conséquences physiques et psychologiques des violences sexuelles. Conclusion : Au premier abord, la prise en charge d'une patiente victime de violences sexuelles peut sembler complexe pour le médecin. Mais selon les femmes, il suffit de peu pour que leur généraliste soit aidant. MOTS-CLES : Violences sexuelles, médecine générale, femmes, attentes, consultation, guide Introduction En France entre 2010 et 2012, 0,4% des femmes ont été victimes de viols ou de tentatives de viols (ONDRP and INSEE, n.d.) et 20,4% des femmes déclarent avoir subi au moins une forme de violences sexuelles au cours de la vie (Bajos, N., & Bozon, M. (Eds.). (2008). Enquête sur la sexualité en France. Pratiques, genre et santé. Paris: La Découverte) dont 59% l'ont été pour la première fois avant 18 ans. Parmi ces femmes, 26% ont été vues par un médecin suite à cet incident et 8% lui en ont parlé. Afin d'améliorer la prise en charge des violences sexuelles faites aux femmes, un plan gouvernemental a été instauré depuis 2004 (Plan Gouvernemental. Plan global de lutte contre les violences faites aux femmes 2005-2007 : 10 mesures pour l'autonomie des femmes. 2004). Il propose des stratégies concrètes de prise en charge aux professionnels de santé comme l'importance d'un dépistage systématique pendant la consultation, le soutien de la victime dans ses démarches et son orientation vers le réseau de partenaires de soins. Peu d'études ont interrogé ces femmes victimes sur ce qu'elles attendaient d'une prise en prise en charge par leur médecin généraliste. L'objectif de la recherche était de recueillir et d'identifier les attentes des femmes ayant vécu des violences sexuelles en matière de prise en charge par leur médecin généraliste ainsi que leur avis sur le dépistage systématique des violences sexuelles en consultation.

  franco-algérienne. (Annexe 1) Un tableau regroupe les caractéristiques des médecins généralistes des femmes participant à l'étude. (Annexe 2) Méthode du recueil des données Une méthode qualitative a été menée au travers d'entretiens individuels semi-dirigés. Le guide d'entretien a évolué au cours de la recherche pour l'améliorer. (Annexe 3) Les entretiens ont été réalisés d'avril à décembre 2015 dans différentes régions : Ile de France, Midi Pyrénées, Aquitaine et Languedoc Roussillon. Le lieu de la rencontre était choisi par la femme. L'enregistrement était fait sur dictaphone ou téléphone portable. La fiche de données socio-épidémiologiques et un consentement étaient remplis et signés par chaque femme. Au début des entretiens, un pseudonyme était choisi pour garantir l'anonymat. Chacun des entretiens a été retranscrit intégralement. L'accord d'un Comité d'Ethique (Annexe 4) a été obtenu afin de procéder à l'analyse des données Les femmes rencontrées avaient toutes vécu différents types de violences sexuelles. On retrouvait majoritairement des viols et des attouchements. Etaient retrouvés également des IVG forcées, des pratiques sexuelles imposées, des refus de contraception, des tentatives de viols. Des faits d'exhibitionnisme et de prostitution ont aussi été rapportés. Pour chaque entretien, une analyse longitudinale (contexte d'énonciation) a été effectuée. Puis, l'analyse transversale des verbatim a comporté une phase de séquençage et a respecté un double codage indépendant par deux chercheurs assurant la triangulation des données. Enfin, la catégorisation et la thématisation ont été réalisées à l'aide d'un tableau Excel ©. Le principe de réflexivité a été pris en compte tout au long de la recherche, en tentant de faire abstraction d'un maximum des représentations personnelles des chercheurs.

  « J'avais tout le temps mal au ventre, tout le temps » -Lotus. Les troubles psychologiques étaient fréquents « Je fais énormément de crises d'angoisse » -Anne ; « Tout ce qui m'intéressait c'était de mourir » -Marmar. Elles parlaient d'anxiété, de dépression, de troubles du comportement alimentaire... La majorité des femmes considère la prise en charge des victimes de violences sexuelles et de leurs symptômes comme étant du ressort du médecin généraliste. « Ça ressort plus de la médecine générale, parce quand on a mal au ventre, qu'on est constipée, qu'on a une éruption de boutons, c'est pas chez le psychiatre qu'on va » ; « Quand j'étais au fond du trou, c'était chez mon médecin traitant que j'allais » -Zébrette. « Elle accepte que je sois dans sa salle d'attente en train de pleurer même si j'ai pas rendez-vous. Je reste dans la salle d'attente, pour moi c'est une protection quoi » -Anne. Ça permettrait d'avoir des consultations qui sont remboursées » -Zébrette Le genre et l'âge du médecin ne semble pas être une caractéristique discriminante dans notre échantillon. « J'irais plus vers un homme, parce que les femmes sont pas toujours objectives » -Marie. « C'est un choix, je cherche les femmes » -Lotus . « Homme ou femme peu importe. Peut-être femme ça serait plus simple » -Marie. Par contre elles accordent de l'importance à la formation. « Les médecins généralistes doivent se former, à part eux, je vois pas en quels professionnels on ferait suffisamment confiance pour en parler » -Sybille. De façon plus générale, plusieurs femmes nous ont rappelé qu'un motif de consultation pouvait en cacher un autre. Ainsi, elles attendaient de leur médecin qu'il cherche plus profondément le véritable motif de consultation. « Je me suis souvent sentie traitée à la légère en fait. Parce que tous mes symptômes cachaient quelque chose de plus profond, donc c'était toujours la surface qui était prise en charge » -La Mouette « J'aimerais juste qu'il m'aide à aller mieux » -Marie « Je venais reprendre de l'oxygène, essayer de comprendre, essayer d'avancer » -Lotus « Je crois que c'est très important, dans le sens où on peut le détecter, et du coup peut-être faire des choses pour que ça ne se passe plus » -Nina « J'avais des symptômes physiques, je ne venais pas forcément chercher une pilule miracle. Je venais chercher une explication » « Faut arrêter de droguer les gens » -La mouette « Aucun médecin ne m'a dit que j'avais le droit de porter plainte avant mes 18 ans […] or j'aurais eu besoin de savoir que j'étais une victime légitime auprès de la justice, et je pense que j'aurais porté plainte plus rapidement » -Sybille « Le message à faire passer à quelqu'un à qui ça vient d'arriver, c'est « On peut s'en sortir ». C'est pas une maladie hein, c'est important » -Karen Ces femmes ont manifesté la volonté de rencontrer des psychologues, psychiatres, associations et groupes de paroles. « Elle aurait peut-être eu plus connaissance du réseau associatif, et même me conseiller l'association ». Elles attendaient de leur médecin un certain nombre de savoir-être : ne pas juger, ne pas remettre en question leur statut de victimes, instaurer un climat de confiance et être sensibilisé au féminisme. « Quelqu'un qui ne va pas faire du slut-shaming, qui va pas me dire « c'est ta faute parce que tu étais habillée en jupe » Elles ont également manifesté la volonté d'être orientées vers des aidants : « Elle aurait pu juste me conseiller un psychiatre » -Sybille. « Elle aurait peut-être eu plus connaissance du réseau associatif et même me conseiller l'association… » -Nina. « Ça peut être bien ça je pense. Un accompagnement thérapeutique comportemental pour ce genre de chose, en travail de groupe, avec des personnes qui ont vécu des choses similaires » -Marie L'examen clinique nécessitait une attention particulière. « Je suis survivante de l'inceste, de viol, je peux pas me déshabiller facilement » -La Mouette. « Ce que j'ai du mal, c'est qu'on me touche » -Anne. « Me laissant relever moi-même par exemple mon T-shirt, si elle veut prendre ma tension ou vérifier quelque chose et tout. Alors que chez d'autres médecins, ils font des gestes automatiques, te soulèvent la manche comme ça. Ouais, j'aime pas trop ça. Là je préfère quelqu'un qui vraiment parle et me dise je vais faire ça, là on va vérifier ça » -Anaïs Leur avis sur le dépistage systématique « Y a beaucoup de gens qui n'en parlent pas, donc c'est au moins leur donner une chance d'en parler » -Anne. « Enfin, si on me pose la question, je vais peut-être dire non, mais après ça va me trotter dans la tête » -La mouette. « Moi-même je vais pas aller dire à mon médecin « j'angoisse, c'est peut-être lié au fait que je me suis fait agresser il y a 3 ans. C'est pas une histoire que j'amène comme ça » -Anaïs « Ça peut paraître gênant pour certaines personnes » -Elise « Si je vais me faire soigner pour une angine, je vois pas en quoi ça le concerne » -Sophie Concernant le dépistage systématique, les réponses données par les femmes ont été éclectiques allant du « pertinent » au « dérangeant ». Une grande majorité a mis en avant que cette question permettait d'ouvrir une réflexion. « Enfin, si on me pose la question, je vais peut-être dire non, mais après ça va me trotter dans la tête ». Le ressenti était donc plutôt en faveur d'un dépistage lors des entrevues.

  France des progrès sont à noter : création d'un nouvel item 10 à l'ECNi « violences sexuelles », des enseignements spécifiques sont dispensés dans certaines facultés ("DUMG Toulouse -Enseignement théorique à jour 2014," n.d.) ("Catalogue-deformation-des-professionnels-MDDF-Edition-2012.pdf," n.d.), l'existence d'un espace dédié aux professionnels sur www.stop-violences-femmes.gouv.frPropositions des femmes pour améliorer le vécu des consultations avec leur médecin traitant et la prise en charge des femmes victimes de violences sexuelles :Selon les femmes de notre étude, le médecin généraliste, peu importe son âge ou son genre, devrait être formé à l'abord et à l'écoute des violences et aux psychotraumatismes qui en découlent. Il/elle ne devrait pas être dans le jugement et ne pas remettre en question le statut de victime ou les dires des patientes. Plusieurs études dont une revue de littérature suisse (Cousin G, Schmid Mast M. Rev Med Suisse. 2010 Jul 28;6(257):1444-7) montrent une préférence des patientes à consulter des praticiens du même sexe en ce qui concerne les examens intimes. Les patients parleraient également plus facilement aux médecins femmes. Selon les recommandations de la 7ème Conférence de consensus de la Fédération Française de Psychiatrie concernant les conséquences des maltraitances sexuelles (novembre 2003), la consultation doit permettre à la victime d'exprimer sa souffrance sans être remise en cause, de recueillir sa parole, d'être examinée sous une forme respectueuse. Le praticien doit l'aider à anticiper le parcours ultérieur. Du fait du polymorphisme de la clinique, chaque médecin doit avoir reçu une formation lui permettant d'évoquer le diagnostic devant des signes en rupture avec le comportement antérieur de la personne, non expliqué par les étiologies habituelles. En cas de difficulté, il doit pouvoir avoir accès rapidement à un centre-ressource. Les femmes interrogées dans notre échantillon insistaient sur l'importance de l'instauration par le médecin d'un climat de confiance propice à l'expression, à l'écoute et au fait qu'il soit sensibilisé aux symptômes physiques et aux conséquences psychologiques pouvant résulter d'une agression sexuelle. Savoir écouter, poser des questions sans curiosité déplacée et expliquer la prise en charge faisaient également partie des attentes. L'examen physique nécessiterait des précautions particulières comme de leur expliquer le déroulement de l'examen et les raisons de cet examen ainsi que de leur demander leur accord avant de les toucher ou de soulever un vêtement. Les contacts physiques, le déshabillage et l'examen gynécologique pouvant rappeler les violences vécues. Les femmes souhaitaient être accompagnées et éventuellement orientées vers un psychologue, psychiatre, associations, groupes de parole, sites internet, livres, sans pour autant se voir systématiquement prescrire des médicaments psychotropes. Elles attendaient d'être encouragées par leur médecin à faire valoir leurs droits, en leur expliquant notamment qu'elles pouvaient porter plainte à tout âge. Elles avaient un besoin marqué d'être rassurées et d'entendre de leur médecin qu'elles pouvaient s'en sortir. Le concept de « patient-expert » : L'originalité de la discussion de l'information recueillie se trouve davantage dans l'éclairage apportée par le concept de « patients experts » lancé en France dès 2011. Le patient-expert est réflexif, il cherche de l'information sur ce qui lui arrive et sur ses réactions. Il accumule un savoir expérientiel qui peut compléter et orienter le savoir clinique du praticien. « Le patient-expert « parfait » refusera dans sa relation au médecin le modèle paternaliste pour lui préférer le modèle dit informatif » (Boudier F. 2012) Cette recherche plaçant l'expérience des femmes au centre du débat a permis de prendre en compte les propositions de femmes victimes de violences sexuelles sur ce qu'elles souhaitaient lors de leur prise en charge en médecine générale. Il ne s'agit pas ici d'un consensus, il serait intéressant de réaliser une recherche sur base de ces résultats afin d'obtenir le consensus d'un groupe de femmes et de « patientes expertes » sur ces propositions. Permettre aux femmes agressées sexuellement de s'exprimer sur leurs attentes est un abord original car peu utilisé dans la littérature. Le choix de la méthode qualitative donne un caractère explorateur et novateur à ce travail. Des limites peuvent être relevées : aucune femme de plus de 50 ans n'a pu être recrutée et beaucoup de femmes interrogées avaient déjà parlé de leur histoire de violences sexuelles. Conclusion Au premier abord, la prise en charge d'une patiente victime de violences sexuelles peut sembler complexe pour le médecin. Mais selon ces femmes, il suffit de peu pour que leur généraliste soit aidant. Le dépistage systématique peut être un outil dans la prise en charge des violences sexuelles. Cependant, il est nécessaire que le médecin généraliste sache aussi reconnaître les signes évocateurs, qu'il soit sensibilisé et formé aux répercussions sur la santé des violences sexuelles et à leur prise en charge. Des recommandations existent pour reconnaître, soigner et prévenir les maltraitances sexuelles à tout âge. Pour aller plus loin, il serait intéressant que d'autres travaux étudient les attentes des hommes ayant vécu des violences sexuelles. En effet, les femmes ne sont pas les seules à en être victimes. Les auteurs ne déclarent aucun conflit d'intérêt

Aucun financement n'a été demandé pour cette étude

Remerciements aux femmes ayant accepté de participer à l'étude ainsi


domain: info.info-ai stat sdv

text:
M.D I C Conforto

Chafik Samir

F Chausse

A A Goldstein

B Pereira

M.D Emmanuel Coudeyre
email: ecoudeyre@chu-clermontferrand.fr

Ph.D F Samir

Ph.D A Chausse

M.D B Goldstein

Ph.D Pereira

Comparison of psychometric properties between the Labin, a new electronic dynamometer, and the Jamar: Preliminary results in healthy subjects

Keywords: Handgrip, Strength, Dynamometer Mots-clés : Poignée, Force, Dynamomètre

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Institutional review board

All the authors declare that they do not have any conflict of interest to declare.

Introduction

Strength is only one of the elements of grasping, which also requires sensation, eye-motor coordination, and memory. Many factors intrinsic to an individual influence this force. For instance, men are generally stronger than women [START_REF] Agnew | Hand function related to age and sex[END_REF][START_REF] Peters | Revised normative values for grip strength with the Jamar dynamometer[END_REF]. Grip strength increases with age, peaking at around 30 to 45 years, and then diminishes. The dominant hand's grip strength is approximately 10% greater than the non-dominant hand's, particularly in right-handed people. Left-handed people usually have equal strength in their two hands [START_REF] Petersen | Grip strength and hand dominance: challenging the 10% rule[END_REF]. A person's type of work or leisure activity also influences their grip strength [START_REF] Josty | Grip and pinch strength variations in different types of workers[END_REF].

Impaired grasping is common and has an impact on social and professional quality of life, hence its assessment is vital. Grip strength is frequently measured in clinical settings, for instance during follow-up, rehabilitation, prognosis [START_REF] Pincus | Quantitative measures to assess, monitor and predict morbidity and mortality in rheumatoid arthritis. Baillie ̀re[END_REF], pre-surgery strength assessment, injury assessment, and evaluation of work-readiness.

A number of instruments for measuring grip strength are available, but not all have proven validity.

Validity is an instrument's ability to actually measure what is asked. It is evaluated by comparing a tool against its gold standard and is expressed using a correlation coefficient that indicates the strength of association between the two instruments [START_REF] Fess | The need for reliability and validity in hand assessment instruments[END_REF]. Reliability is the fact that repeating a measurement yields the same result. It is expressed using an intraclass correlation coefficient [START_REF] Koo | A Guideline of Selecting and Reporting Intraclass Correlation Coefficients for Reliability Research[END_REF].

The Jamar is a hydraulic hand dynamometer developed in 1954 by Bechtol [START_REF] Bechtol | Grip test; the use of a dynamometer with adjustable handle spacings[END_REF]. It assesses maximal grip strength in kilograms (kg) between the fingers and thenar eminence. It is currently the gold standard for measuring maximal grip strength [START_REF] Mathiowetz | Reliability and validity of grip and pinch strength evaluations[END_REF][START_REF] Hamilton | Grip strength testing reliability[END_REF][START_REF] Peolsson | Intra-and inter-tester reliability and reference values for hand strength[END_REF] and is recommended by the American Society of Hand Therapist [START_REF] Fess | Guidelines for evaluating assessment instruments[END_REF]. Yet its use is limited, particularly in the elderly and in patients with advanced neuromuscular diseases. To our knowledge, there are currently no validated electronic instruments that can display a grip force curve relative to time on a computer.

The Labin is an electronic dynamometer prototype being developed at the LIMOS laboratory in Clermont-Ferrand, France. It comprises a strength handle connected to a pressure sensor that is, in turn, connected to a computer. When the subject squeezes the handle, a curve showing force in kilograms relative to time is displayed in real-time on the screen. This study sought to compare the Labin electronic dynamometer for measuring maximal grip strength with the gold standard, the Jamar, in healthy subjects. A secondary aim was to compare the two tools in terms of discomfort during use.

Material and methods

Study and population

This was a single-center exploratory study. Healthy subjects were enrolled between March and April 2016 in the Physical Medicine and Rehabilitation and Geriatrics Department of the Clermont-Ferrand university hospital. They were recruited on a voluntary basis and were not patients of the principal investigator's department. The subjects included had to be between 20 and 60 years of age, be volunteers and give consent. Subjects were not included if they had prior surgery or injury of the upper extremities, cognitive disorders, neurological disease, entrapment neuropathy of the upper extremities, diabetes, thyroid dysfunction, any skin disorder of the hand, or chronic alcohol dependence. The following characteristics were recorded: age, sex, body mass index, dominant hand, occupation, and leisure activity (sports, musical instrument, and DIY or craftwork).

The study protocol was approved by the research ethics committee of South-East France (Sud-Est 6), No. 2015-A1732-47, and the "Agence Nationale de Sécurité du Médicaments et des Produits de Santé (ANSM)": No. DMDPT-BLOC/MM/2015-A01732-47. The study was registered on ClinicalTrial.gov as NCT 028476. The trial was conducted in compliance with both Good Clinical Practices and the Declaration of Helsinki, in accordance with French law. All participants provided their written consent to participate in the study after being informed in detail about the study's procedures.

Measurements

Subjects were positioned according to the recommendations of the American Society of Hand Therapists: comfortably seated in a chair without armrests, feet flat on the floor, buttocks against the back of the chair, hips and knees flexed at 90° angles, shoulder adducted and in neutral rotation, elbow flexed 90°, forearms in neutral position, and wrist in 0-30° extension and 0-15° ulnar deviation. The dynamometer was handed over vertically and in line with the forearm to maintain the standardized positions. The Jamar was in the second handle position, as recommended in the literature.

Both dynamometers were calibrated before starting the trials. The tool was zeroed by performing a blank measurement for 5 seconds. All subjects had a trial run (during which they were not encouraged) so they could familiarize themselves with the dynamometer.

The measurement was then made as described in the literature [START_REF] Innes | Handgrip strength testing: A review of the literature[END_REF][START_REF] Shechtman | Reliability and validity of the DynEx dynamometer[END_REF]. The mean of three 5second maximal grip strength trials, with a 30-second pause between trials on the same hand, was calculated. Subjects performed three trials with the right hand and then, after a 2-minute break, three with the left. The same session was conducted with the second instrument after a 5-10-minute break. The testing sequence (Jamar and then Labin or Labin and then Jamar) was randomized. The operator encouraged the subject during each trial. The subject could not see the curve being displayed by the Labin [START_REF] Innes | Handgrip strength testing: A review of the literature[END_REF][START_REF] Shechtman | Reliability and validity of the DynEx dynamometer[END_REF].

Subjects were then asked to rate the handgrip's discomfort on a simple verbal scale from 0 to 10. A higher score on the discomfort scale indicated greater discomfort. The observers were trained and were involved consistently so as to limit interexaminer variability.

Statistical analysis

The sample size was estimated to validate the Labin electronic dynamometer for measuring maximal grip strength compared to the gold standard Jamar. More precisely, it was decided to include 30 healthy subjects to highlight a correlation coefficient greater than 0.5 (expected value) for a two-sided type I error at 5% and a statistical power equal to 80% using Fisher's z test comparing a correlation value to a reference value (0 as the null hypothesis).

Statistical analyses were performed using Stata software (version 13, StataCorp, College Station, US). Continuous data were expressed as mean and standard-deviation (SD) or median [interquartile range] depending on whether they were normally distributed. The Shapiro-Wilk test was used to confirm the Gaussian normality assumption. The reproducibility was measured with the intraclass correlation coefficient (ICC) estimated with a random-effects effects model considering between-subject and within-subject variability. The patient was considered as a random effect and the following fixed effects were studied: hand dominance (yes/no), dynamometer (Jamar/Labin) and their interactions, and trials. The normality of residuals was studied using the Shapiro-Wilk test. A logarithmic transformation was applied to achieve normality of the dependent variable and Sidak's type I error correction was applied to consider multiple comparisons. The standard error of the measurement (SEM) (= SD * √(1-ICC)) was calculated. Good accuracy is said to be equivalent to SEM ≤ 1/2 (SD). The concordance between quantitative measurements was analyzed using Lin's concordance coefficient. Concordance coefficients and ICCs are presented with 95% confidence intervals. Finally, a paired t-test was performed to compare the discomfort between the Labin and Jamar dynamometers.

Results

We enrolled 34 healthy subjects. The sample population comprised 18 women and 16 men. Mean age was 39 years ± 12 and mean body mass index was 22.4 ± 3 kg/cm². Thirty-one subjects were right-handed and three were left-handed, hence 91% of the population were right-handed. Most subjects had sedentary (79%) and non-manual (88%) jobs, exercised regularly (77%), did not play a musical instrument (79%), and did not engage in DIY or craftwork (70%). Subject characteristics are detailed in Table 1.

The mean force measured in the three trials are summarized in Table 2. The reproducibility evaluated using the Jamar's ICC was 0.91 [0.84; 0.95] for the dominant hand and 0.90 [0.83; 0.95] for the non-dominant hand. For the Labin, the ICC was 0.81 [0.69; 0.89] for the dominant hand and 0.86 [0.76; 0.92] for the non-dominant hand. Mean force measured with the dominant hand was 32.8 ± 12 kg with the Jamar and 32.6 ± 11.7 kg with the Labin (random-effects model: p=0.83).

Mean force measured for the non-dominant hand was 30.1 ± 11 kg with the Jamar and 29.6 ± 10 kg with the Labin (random-effects model: p=0.55). Furthermore, no significant difference was found between Labin and Jamar (random-effects model: p=0.58, -0.27 [-1.24; 0.69]). There was a significant difference between the dominant and non-dominant hands for the Jamar (p<0.001) and Labin trials (p<0.001), but the interaction was not significant (p=0.80). For the dominant hand, the SEM was 3.6 for the Jamar and 5.2 for the Labin, less than half of the respective standarddeviations.

The Lin concordance coefficient between the Labin and Jamar measurements was 0.90 [0.83; 0.96] for the dominant hand and 0.83 [0.72; 0.93] for the non-dominant hand (Fig. 1). During the tests, we subjectively observed differences in curve profile (Fig. 2) between genders: Male subjects had less uniform results over the three measurements of the same hand.

On the 10-point discomfort scale, the Labin scored a mean of 4.5 ± 2 while the Jamar was 3.9 ± 2.1, with no significant difference (p = 0.15, effect-size = 0.30 [-0.18; 0.78]).

Discussion

Numerous tools are currently used to measure grip strength. Electronic dynamometers are coming onto the market, but to our knowledge none can provide real-time measurements and display a curve on a computer screen.

In our study, the Labin's validity was 0.91 for the dominant hand and 0.86 for the non-dominant hand, which we deemed acceptable. Some authors use a correlation coefficient value between two tools of more than 0.75 as a criterion of strong association [START_REF] Portney | Foundations of clinical research : Applications to practice[END_REF]. For others, only a coefficient greater than 0.9994 is acceptable [START_REF] Fess | A method for checking Jamar dynamometer calibration[END_REF]. A significant difference between dominant and non-dominant hands was highlighted for the Labin and Jamar dynamometers.

We found good reproducibility for both dynamometers, meaning they can display the same result in a subject regardless of the operator and regardless of when the measurement is made. Thus we consider the Labin to be reliable in clinical practice, particularly in medical settings involving a number of healthcare professionals and long-term patient follow-up.

The Labin has good measurement precision because it uses a pressure sensor and shows force in kilograms relative to time in real-time on the screen, whereas for the Jamar, the human eye measures the value indicated by the needle. The newness of this prototype means there is no true gold standard that is completely equivalent. Since the Jamar comes the closest, it was chosen as the reference in this study. There were no significant differences in discomfort between the two dynamometers. The most frequent criticism of the Labin was the instability of its handle, while that of the Jamar was the hardness of the material it is made of. It should be noted that a new Labin model is being made for market launch that is more comfortable to hold.

Of the potential biases in our study, the fact the Jamar was standardized in the second handle position may have caused difficulty for subjects with small hands and may thus have underestimated their grip strength.

We noted that peak force tended to decrease during the trials. The subjects' maximal force was often obtained in the first measurement despite the breaks and the lack of pain stated by the subjects. The difference in the value obtained between the first and third measurements may have been caused by a number of factors. For instance, the subjects may have lacked strength because of fatigue, or, on the contrary, may have improved because of a learning or competitive effect [START_REF] Mathiowetz | Reliability and validity of grip and pinch strength evaluations[END_REF].

Regarding the study population, our sample comprised of more sedentary workers than physical workers and few laborers such as manual workers, despite recruiting from a fairly wide range of occupations.

As for handedness, the ratio of right-handed to left-handed subjects was fairly representative of that in the general population. We noted that two of the three left-handed subjects had greater strength with the right hand. This may be due to the fact that left-handed people are often ambidextrous and that, despite being left-handed, their right hand is their force producing hand and their left hand is their stabilizing hand.

All of these results suggest the Labin could be used in pathological conditions, particularly in geriatrics, rheumatology, hand surgery, or in patients with neuromuscular deficits. It has been shown that muscle strength may be correlated with an inability to get back up after a fall in the elderly or with morbidity in patients with rheumatoid arthritis [START_REF] Pincus | Quantitative measures to assess, monitor and predict morbidity and mortality in rheumatoid arthritis. Baillie ̀re[END_REF].

Our interest in the Labin is that it may, in addition to quantitative analysis, be able to show grip strength qualitatively thanks to the continuous nature of the force curve. Indeed, additional data may be extracted from this curve, such as mean time to reach maximum force, endurance (as shown by the length of the curve between two peaks), and difference relative to a perfect signal (area under the curve). It may be worthwhile to draw up pathologic curve profiles and potentially detect a lack of endurance in certain patients who are nevertheless able to achieve a peak force within the normal range.

Conclusion

In our study, we have shown the Labin electronic dynamometer has acceptable validity and reproducibility. With the Labin, we may be able to perform innovative grip strength analysis on a quantitative and qualitative level. Its use is promising in pathological conditions, particularly in geriatrics, rheumatology, hand surgery, and neuromuscular diseases. Further studies will be needed to validate the Labin in these patient populations.

Financial disclosure and conflict of interest:

All the authors declare they have no conflict of interest.

Figure legends

  Nationale de Sécurité du Médicaments et des Produits de Santé (ANSM): N° DMDPT-BLOC/MM/2015-A01732-47 Commission de Protection des Personnes (CPP) Sud-Est VI: N° 2015-A1732-47 Trial registry: Clinical Trials: N° NCT 028476 Financial disclosure and conflict of interest:

Fig. 1 .Fig. 2 .

 12 Fig. 1. Handgrip strength correlation between the Labin and Jamar dynamometers Fig. 2. Labin curve profile over three trials

Table titles Table 1 .

 titles1 Patient characteristics

Table 2 .

 2 Strength measured during the three trials with the Jamar and Labin dynamometers

	Appendices
	Appendix 1. Labin

FIGURES


Mathieu Hatt

François Lucia

Ulrike Schick

Dimitris Visvikis

Multicentric validation of radiomics findings: challenges and opportunities

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Predicting patients' outcome after treatment is challenging. Usual clinical variables and standard exploitation of imaging fails to deliver actionable predictive models with sufficient accuracy in a number of cancer types and associated treatments, including cervical cancer, one of the most frequent malignant tumour in women with over 500 000 cases annually worldwide, associated with 270 000 deaths [START_REF] Bray | Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries[END_REF]. For women diagnosed with locally advanced cervical cancer (LACC), treatment in Western countries is usually pelvic external beam radiotherapy (EBRT) in association with cisplatin-based chemotherapy (CRT), followed by brachytherapy (BT). Alternatively, preoperative neoadjuvant chemotherapy (NACT) is increasingly being considered in Asian countries in order to reduce tumour volumes and allow for a surgical removal. Within this context, there is a crucial need to identify biomarkers predictive of outcome, in order to personalize treatment. Radiomics has emerged as a potential solution to provide such biomarkers from available routine pre-treatment images, by considering that the content of images can be extracted through machine (deep) learning, beyond the capabilities of the human eye, even the expertly-trained one [START_REF] Visvikis | Artificial intelligence, machine (deep) learning and radio(geno)mics: definitions and nuclear medicine imaging applications[END_REF]. The resulting features can be mined, similarly to other -omics domains, in order to identify the relevant ones. One advantage of radiomics is that it exploits diagnostic images that are available already, so it does not require additional exams (imaging or biological).

Despite a number of encouraging results, radiomics faces challenges that have until now prevented its widespread use in clinical practice. These include false-positives [START_REF] Welch | Vulnerabilities of radiomic signature development: The need for safeguards[END_REF], the lack of standards and resulting limited reproducibility [START_REF] Vallières | Responsible Radiomics Research for Faster Clinical Translation[END_REF], the lack of fully automated detection and delineation, and the lack of multicentric validation [START_REF] Upadhaya | Comparison of Radiomics Models Built Through Machine Learning in a Multicentric Context With Independent Testing: Identical Data, Similar Algorithms, Different Methodologies[END_REF]. This last point is addressed within the context of LACC by the study by Sun, et al. recently published in EBioMedicine [START_REF] Sun | Radiomic analysis for pretreatment prediction of response to neoadjuvant chemotherapy in locally advanced cervical cancer: A multicentre study[END_REF]. They investigated the prediction of response to NACT in LACC using radiomic features extracted from pre-treatment magnetic resonance imaging (MRI) T1 and T2 sequences. They included 275 patients from 8 cohorts (5 were used as a training set, 3 as the testing set). IBSI (image biomarkers standardization initiative)-compliant radiomic features were extracted from the two MRIs, as well as from both the intratumoural and the peritumoural regions manually delineated by radiologists. In the training set, a support vector machine with recursive feature elimination was exploited to identify the most relevant features. Then a random forest was used to build models, which were then evaluated in the testing set. Importantly, the robustness of the findings was evaluated by training/testing the models on different training and testing sets. The models based on a single sequence and single tumour region reached AUCs ≥0.94, with 100% specificity but limited sensitivity (76% at best). Those based on combinations of sequences reached AUCs ≥0.98, with 100% specificity and sensitivity up to 84% for the best model. Moreover, these results were robust to different splitting of the data into training and testing sets. In a subset of 232 patients for which the clinical variables (age, FIGO stage, gross type) were available, the radiomic models significantly outperformed the model based on clinical features (AUC of 0.6). This is in line with the results of Lucia, et al. with the radiomic model reaching an accuracy of 0.90-0.97 versus 0.56-0.60 for the clinical model [START_REF] Lucia | External validation of a combined PET and MRI radiomics model for prediction of recurrence in cervical cancer patients treated with chemoradiotherapy[END_REF].

© 2019 published by Elsevier. This manuscript is made available under the CC BY NC user license https://creativecommons.org/licenses/by-nc/4.0/ Version of Record: https://www.sciencedirect.com/science/article/pii/S2352396419305778 One challenging aspect of multicentric radiomic studies is the sensitivity of radiomic features with respect to the variability of scanner models, acquisition protocols and reconstruction algorithms and parameters. Recently, a radiomic model exploiting FDG positron emission tomography (PET) and MRI apparent coefficient diffusion (ADC) map to predict outcome in LACC was validated in a multicentric context (3 different centers), thanks to the use of the ComBat harmonization technique [START_REF] Lucia | External validation of a combined PET and MRI radiomics model for prediction of recurrence in cervical cancer patients treated with chemoradiotherapy[END_REF]. In that respect, the study of Sun, et al. showed that z-score normalization [START_REF] Chatterjee | Creating robust predictive radiomic models for data from independent institutions using normalization[END_REF] of each slice of the MR images intensities as well as of the features of each patient could allow good performance, despite different 3.0-T and 1.5-T MRI scanner models from several different vendors across the 8 centres.

One important limitation of the study by Sun, et al. is that regions of interest were manually delineated. Although reproducibility was evaluated through blind analysis by two radiologists, a fully automated delineation will need to be developed so the proposed radiomic model can be exploited clinically. Artificial intelligence has already shown the potential of highly accurate image segmentation within the multimodality imaging context [START_REF] Guo | Deep Learning-Based Image Segmentation on Multimodal Medical Imaging[END_REF]. Another limitation is that clinical data were not available for all patients, compromising the comparison between the radiomic models and standard clinical variables carried out only on a subsample of the overall study population. Finally, the models might not be directly applicable to cohorts in the Western countries for which treatment management differ.

Nonetheless, the work by Sun, et al. contributes to the growing number of studies that show validating radiomic models in a multicentric context is feasible. Such results may help the radiomics approach to translate faster into the clinical routine practice.

Author Disclosure

The authors declare no conflicts of interest.