Monitoring is an important run time correctness checking mechanism. This paper introduces the notions of monitorability and strong monitorability for partially observable stochastic systems, and gives necessary and sufficient conditions characterizing them. It also presents important decidability and complexity results for checking these properties for finite state systems. Furthermore, it presents general monitoring techniques for the case when systems are modeled as quantized probabilistic hybrid automata, and the properties are specified as safety or liveness automata. Experimental results showing the effectiveness of the methods are given.

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The selective laser melting of tin bronze (CuSn10) powder was performed with a laser energy density intensity level at 210, 220, and 230 J/mm2. The composition was homogeneous with almost all tin dissolved into the matrix. The grain size of the obtained alpha copper phase was around 5 μm. The best properties were achieved at 220 J/mm2 laser energy density with a density of 8.82 g/cm3, hardness of 78.2 HRB (Rockwell Hardness measured on the B scale), yield strength of 399 MPa, tensile strength of 490 MPa, and an elongation that reached 19%. “Balling effect” appeared and resulted into a decrease of properties when the laser energy density increased to 230 J/mm2.

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The dynamic responses of slender cylinders with high aspect ratios undergoing vortex-induced vibrations (VIV) are studied.In detail, a three-dimensional model predicting the VIV responses in both the In-Line and Cross-Flow directions of slender cylinders is proposed based on the nonlinear equation governing the dynamic deformation and a wake oscillator. The tension in the cylinder is estimated according to the incoming stream velocities. To predict the VIV responses, the cylinder is discretized into finite segments, and the vibrations of each segment are estimated from solving the governing equation when the excitation forces are modelled using the Van Der Pol's wake oscillator. Considering that the wake oscillator model estimates the excitation forces according to the dynamics of the cylinder, it reveals the interactions between the flow and the dynamics of the cylinder. In order to verify the model calculating the mean tension, the VIV responses, which has been experimentally tested, is numerically studied. The comparison between the numerically predicted and experimentally measured responses shows that, the approach, especially the novel tension model, proposed herein is reliable as the frequency

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