On the Experimental Evaluation of Vehicular Networks: Issues, Requirements and Methodology Applied to a Real Use Case

One of the most challenging fields in vehicular communications has been the experimental assessment of protocols and novel technologies. Researchers usually tend to simulate vehicular scenarios and/or partially validate new contributions in the area by using constrained testbeds and carrying out minor tests. In this line, the present work reviews the issues that pioneers in the area of vehicular communications and, in general, in telematics, have to deal with if they want to perform a good evaluation campaign by real testing. The key needs for a good experimental evaluation is the use of proper software tools for gathering testing data, post-processing and generating relevant figures of merit and, finally, properly showing the most important results. For this reason, a key contribution of this paper is the presentation of an evaluation environment called AnaVANET, which covers the previous needs. By using this tool and presenting a reference case of study, a generic testing methodology is described and applied. This way, the usage of the IPv6 protocol over a vehicle-to-vehicle routing protocol, and supporting IETF-based network mobility, is tested at the same time the main features of the AnaVANET system are presented. This work contributes in laying the foundations for a proper experimental evaluation of vehicular networks and will be useful for many researchers in the area.Comment: in EAI Endorsed Transactions on Industrial Networks and Intelligent Systems, 201

The behavior of statically-indeterminate structural members and frames with cracks present

Arts et Métiers ParisTech, invitation en tant que professeur invité de Paul C. Paris au LAMEFIPCrack stability is discussed as affected by their presence in statically-indeterminate beams, frames, rings, etc. loaded into the plastic range. The stability of a crack in a section, which has become plastic, is analyzed with the remainder of the structure elastic and with subsequent additional plastic hinges occurring. The reduction of energy absorption characteristics for large deformations is also discussed. The methods of elastic–plastic tearing instability are incorporated to show that in many cases the fully plastic collapse mechanism must occur for complete failure.The authors acknowledge Arts et Metiers Paris Tech and Foundation Arts et Metiers for the financial support of the Prof. P.C. Paris’ stay at LAMEFIP in 2008 and 2009. The encouragement of Prof. Ivan Iordanoff, Director of LAMEFIP, is also acknowledged with thanks

Proposition of Dynamic Virtual Link for IPv6 GeoNetworking (GN6) in ETSI

A proposition to ETSI ITS WP3.First, we describe the limitation of Draft EN 302 636-6-1 V0.1.2 (2012-11). Note that this study is based on year November 2012 versions of the ETSI Standards and that the standards constantly evolve. As a result, parameters, primitives and virtual links on GN6ASL may have changed at the time of reading. To overcome the limitation, we propose Dynamic Virtual Link (DVL)

Extended interface ID for virtual link selection in GeoNetworking to IPv6 Adaptation Sub-layer (GN6ASL)

Proposition to ETSI TC ITS WP3 about Draft EN 302 636-6-1 V0.1.2 (2012-11).We describe the limitation of Draft EN 302 636-6-1 V0.1.2 (2012-11). Note that this study is based on year December 2012 versions of the ETSI Standards and that the standards constantly evolve. As a result, parameters, primitives and virtual links on GN6ASL may have changed at the time of reading. We propose a solution to allocate different IPv6 address on each virtual interface in order to distinguish them without changing the addressing scheme in MAC address and GeoNetworking address. The proposition complies also with Dynamic Geographical Virtual Link (DVL)

Echocardiography during submaximal isometric exercise in children with repaired coarctation of the aorta compared with controls

Objective Patients with repaired coarctation (RCoA) remain at higher risk of cardiac dysfunction, initially often only detected during exercise. In this study, haemodynamics of isometric handgrip (HG) and bicycle ergometry (BE) were compared in patients with RCoA and matched controls (MCs). Methods Case-control study of 19 children with RCoA (mean age 12.9 +/- 2.3 years; mean age of repair 7 months) compared with 20 MC. HG with echocardiography followed by BE was performed in both groups. Results During HG (blood pressure) BP increased from 114 +/- 11/64 +/- 4 mm Hg to 132 +/- 14/79 +/- 7 mm Hg, without significant differences. During HG as well as BE, HR increased less in patients with RCoA. There were no significant differences in (left ventricle) LV dimensions or LV mass. The RCoA group had diastolic dysfunction: both at rest and during HG they had significantly higher transmitral E and A velocities and lower tissue Doppler E' and A' velocities. E/E' was higher, reaching statistical significance during HG (p<0001). Conventional parameters of systolic function (FS and EF) were similar at rest and HG. More sensitive tissue Doppler S' was significantly lower at rest in CoA subjects (5.1 +/- 1.5 cm/s vs 6.5 +/- 1 +/- 1 cm/s; p<0.01), decreasing further during HG by 5% in the CoA group (NS) while unchanged in controls. Conclusions We provide first evidence that HG with echocardiography is feasible, easy and patient-friendly. A decreased systolic (tissue Doppler) and impaired diastolic LV function was measured in the RCoA group, a difference that tended to increase during HG

Thyroid hormone levels within reference range are associated with heart rate, cardiac structure, and function in middle-aged men and women

Background: Triiodothyronine (T3) has many effects on the heart, and marked changes in cardiac function and structure occur in patients with (subclinical) thyroid disease. We investigated whether between-subject variation in thyroid hormone levels within the euthyroid range is also associated with heart rate and echocardiographic heart function and structure. Methods: Subjects were selected from the Asklepios study (n=2524), a population-representative random sample of patients aged between 35 and 55 years, free from overt cardiovascular disease at baseline. Analyses were restricted to 2078 subjects (1013 women and 1065 men), not using antihypertensive or thyroid medication nor having antithyroperoxidase antibody levels above clinical cut-off or thyrotropin (TSH) levels outside the reference range. All subjects were phenotyped in-depth and underwent comprehensive echocardiography, including diastolic evaluation. Thyroid function parameters were determined by automated electrochemiluminescence. Results: Heart rate was robustly positively associated with (quartiles of) free T3 (FT3) and T3, both in subjects with TSH levels within reference (0.27-4.2 μU/L) and in narrow TSH range (0.5-2.5 μU/L; p<0.0001). FT3 and T3 were negatively associated with left ventricular (LV) end-diastolic volume but positively associated with relative wall thickness. Total T3 (TT3) was associated with enhanced ventricular contraction (as assessed by tissue Doppler imaging). Free thyroxine, FT3, and TT3 were positively associated with late ventricular filling, and TT3 was associated with early ventricular filling. Conclusion: We have demonstrated a strong positive association between thyroid hormone levels within the euthyroid range and heart rate, and more subtle effects on cardiac function and structure. More specifically, we suggest a smaller LV cavity size (with increased relative wall thickness), an enhanced atrial and ventricular contraction, and LV relaxation with higher circulating thyroid hormones. These results illustrate that variation in thyroid hormone levels, even within the reference range, exerts effects on the heart

A framework for IP and non-IP multicast services for vehicular networks

International audienceEnabling drivers to be connected to the Internet and/or Vehicular Ad-hoc networks, is one of the main challenges of the future networking. This enables drivers to benefit from the existing Internet services as well as emerging ITS applications based on IP or non-IP communications (e.g geonetworking). Many of ITS applications such as fleet management require multicast data delivery. Existing works on this subject tackle mainly the problems of IP multicasting inside the Internet or geocasting in VANETs. This paper presents a new framework that enables Internet-based multicast services on top of VANETs. We introduce a self-configuring multicast addressing scheme based on the geographic locations of the vehicles coupled with a simplified approach that locally manages the group membership to allow packet delivery from the Internet. Moreover, we propose an approach that selects the appropriate network-layer protocol for either geocasting or IP multicasting depending on the vehicles' context and the application requirements. Finally, we present the integration of the designed framework to the ITS reference architecture

Triiodothyronine and free thyroxine levels are differentially associated with metabolic profile and adiposity-related cardiovascular risk markers in euthyroid middle-aged subjects

Background: We previously showed that in healthy young men a less favorable body composition is associated with higher FT3 levels within the euthyroid range. Besides, a higher FT3-to-FT4 ratio has been related to a less favorable metabolic phenotype and more placental growth in pregnant women. In the present study, we therefore investigated whether serum TSH, thyroid hormone levels and the FT3-to-FT4 ratio are associated with metabolic and adiposity-related cardiovascular risk markers in a healthy population of middle-aged euthyroid men and women. Methods: Thyroid parameters were measured in 2524 generally healthy subjects from the Asklepios study (35-55yrs, mean age 46 years). Analyses were restricted to 2315 subjects (1138 women and 1177 men), not using thyroid medication, not having anti-TPO levels above clinical cut-off values nor TSH levels outside the reference range (0.27-4.2 mU/L). Twenty-seven percent of the women and 47.5% of the men were overweight, while 13% of women and 17% of men were obese. Twenty percent of the subjects were active smokers. Serum thyroid function parameters were determined by electrochemiluminescence. Results: (F) T3 and the FT3-to-FT4 ratio were positively related to BMI, waist circumference and components of the metabolic syndrome, i.e. triglycerides, systolic and diastolic blood pressure and fasting plasma glucose, and negatively with HDL-cholesterol levels, whereas FT4 was negatively associated to BMI, waist circumference and triglycerides (all p-values <0.001). TSH related positively to total cholesterol levels (p<0.01), triglycerides and to systolic and diastolic blood pressure (all p<0.001). The FT3-to-FT4 ratio was further positively associated to the adiposity-related inflammation markers interleukin-6 (IL6) and high-sensitive CRP (hs-CRP) and to pulse wave velocity. All associations were adjusted for sex, age, height and smoking and most associations persisted after additional adjustment for weight or waist circumference. Conclusion: In healthy euthyroid middle-aged men and women, higher (F) T3 levels, lower FT4 levels and thus a higher FT3-to-FT4 ratio are consistently associated with various markers of unfavorable metabolic profile and cardiovascular risk