Due to complexity and intractability reasons, most of the analytical studies on the reliability of communication paths in mobile ad hoc networks are based on the assumption of link independence. In this paper, an analytical framework is developed to characterize the random behavior of a multihop path and derive path metrics to characterize the reliability of paths. This is achieved through the modeling of a multihop path as a PDMP (piecewise deterministic Markov process). Two path based metrics are obtained as expectations of functionals of the process: the mean path duration and the path persistence. We show that these metrics are the unique solution of a set of integro-differential equations and provide a recursive scheme for their computation. Finally, numerical results illustrate the computation of the metrics; these results are compared with independent link approximation results.

We consider the estimation of the arrival rate and the service time moments of a M/G/1 queue with probing, i.e., with special customers (probes) entering the system. The probe inter-arrival times are i.i.d. and probe service times follow a general positive distribution. The only observations used are the arrival times, service times and departure times of probes. We derive the main equations from which the quantities of interest can be estimated. Two particular probe arrivals, deterministic and Poisson, are investigated.

We use a probing strategy to estimate the time dependent traffic intensity in an Mt/Gt/1 queue, where the arrival rate and the general service-time distribution change from one time interval to another, and derive statistical properties of the proposed estimator. We present a method to detect a switch from a stationary interval to another using a sequence of probes to improve the estimation. At the end, we compare our results with two estimators proposed in the literature for the M/G/1 queue.

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Abstract. This paper investigates connectivity in one-dimensional ad hoc networks by means of the distribution of the minimum hop count between source and destination nodes.We derive the exact probability distribution of the minimum hop count from the location density of relay nodes in the multihop path selected with the Most Forward within Radius (MFR) scheme. The probability that the source and destination nodes are connected (provided by Ghasemi and Nadser-Esfahani (2006)) can be obtained by summing the probability masses for each possible value of the minimum hop count, which provides new insights to the connectivity probability. Numerical results show the effect of the number of nodes and the transmission range on the minimum hop count.

This paper deals with the problem of the locomotion of robots with two legs with a design inspired by human locomotion (anthropomorphic bipedal robots). The future intention of the research group is to consolidate a robotic platform capable of interacting side by side with the human being, in particular by providing services to people. We propose a dynamic bipedal walking scheme based on a simulated model of inverted pendulum and using the Zero Moment Point (ZMP) as a control strategy. To solve the problem of closed-loop control, the strategy estimates the robot's Center of Mass (CoM) continuously. The formulation, analysis, solution and implementation is done on the Nao robot from Aldebaran Robotics. The strategy was encoded in a NAOqi module in Python, and executed in a Nao V5. The behavior of the robot during the walk demonstrated the success of the strategy. Keyword-Bipedal robot, Center of mass, Dynamic walking, Locomotion, Zero moment point I. INTRODUCTION Despite the great progress made in recent years in robot control, and in particular in the area of bipedal walking schemes, many problems remain open to solution in this area [1]. The inherent complexity of these robots makes their control a difficult task, even with the most advanced hardware. This paper focuses on the predictive control of the model of a bipedal robot, which, following the previous experiences of other research projects of the group, uses an approximation of the behaviour of the leg to an inverted pendulum [2]. The proposed model is estimated in real time, using a simplified method with an approximation of the robot's Centre of Mass (CoM). The formulation, analysis, solution and implementation is done on the Nao robot from Aldebaran Robotics [3]. We selected the Nao robot for its great versatility, its wide range of movements that allows it to perform various tasks [4], which can be controlled through a simple programming algorithm [5]. The path planning for autonomous robots in human environments is one of the areas of greater research in robotics. In the case of robots with legs the possibilities of movement are greater, and therefore the problem is more complex [6]. Thanks to this type of displacement robots have the possibility to navigate rough terrain, unlike the flat floors used by robots with wheels. To do this, legged robots should support their legs in the surrounding environment regions that meet a certain number of characteristics, generally similar to those in flat environments. The rest of the environment does not require these characteristics, reason why they have in general a greater capacity of displacement. The problem of walking robots with legs can be divided into two: the problem of route planning in the environment, and the problem of robot movement along this route [7]. In the first case, a global path planning scheme is usually proposed. These planning schemes consider the placement of the foot in the environment, the configurations of the contact with the terrain, and the connectivity of these configurations. Ac...

This work presents a risk analysis performed to stationary Li-ion batteries within the framework of the STABALID project. The risk analysis had as main objective analysing the variety of hazards and dangerous situations that might be experienced by the battery during its life cycle and providing useful information on how to prevent or manage those undesired events. The first task of the risk analysis was the identification of all the hazards (or risks) that may arise during the battery life cycle. Afterwards, the hazards identified were mapped in the different stages of the battery life cycle and two analyses were performed for each stage: an internal problem analysis and an external peril analysis. For both, the dangerous phenomena and the undesirable events resulting from each hazard was evaluated in terms of probability of occurrence and severity. Then, a risk assessment was carried out according to a predefined risk matrix and a preliminary set of risk mitigation measures were proposed to reduce their probability of occurrence and/or their severity level. The results obtained show that it is possible to reduce the probability of occurrence/severity of all the risks associated to the battery life cycle to acceptable or tolerable levels.

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