A stereo vision-based obstacle detection system in vehicles

Obstacle detection is a crucial issue for driver assistance systems as well as for autonomous vehicle guidance function and it has to be performed with high reliability to avoid any potential collision with the front vehicle. The vision-based obstacle detection systems are regarded promising for this purpose because they require little infrastructure on a highway. However, the feasibility of these systems in passenger car requires accurate and robust sensing performance. In this paper, an obstacle detection system using stereo vision sensors is developed. This system utilizes feature matching, epipoplar constraint and feature aggregation in order to robustly detect the initial corresponding pairs. After the initial detection, the system executes the tracking algorithm for the obstacles. The proposed system can detect a front obstacle, a leading vehicle and a vehicle cutting into the lane. Then, the position parameters of the obstacles and leading vehicles can be obtained. The proposed obstacle detection system is implemented on a passenger car and its performance is verified experimentally.     

Measurement of Mechanical Properties of Thin Film by Membrane Deflection Test

Micro-tensile properties of Au thin films were measured using a membrane deflection testing system. During the membrane deflection test, the deflection of the film was measured by an out-of-plane electronic speckle pattern interferometric (ESPI) system. From the measurement, the tensile loads and strains exerted on the membrane film during the deflection of the film could be determined. Quantitative analysis of the phase maps of the ESPI speckle patterns corresponding to the respective different deflection levels provided the deflection distribution along the testing section of the film. Test pieces were fabricated by electromachining process using 0.5 and 1. 0 μm thick Au films which were deposited on the silicon wafer by sputtering technique. Tensile properties, including elastic modulus, yield and tensile strength, were evaluated in the tensile stress-strain curve determined from the load-deflection relation. These properties were compared to those obtained from the micro-tensile tests. It was found that the yield and tensile strengths obtained from the deflection tests were lesser than those from the micro-tensile tests. Furthermore, the thickness effect, showing the increasing tendency of yield strength with decreasing thickness, was experimentally examined.     

Statistically Steady Incompressible DNS to Validate a New Correlation for Turbulent Burning Velocity in Turbulent Premixed Combustion

Incompressible 3-D DNS is performed in non-decaying turbulence with single step chemistry to validate a new analytical expression for turbulent burning velocity. The proposed expression is given as a sum of laminar and turbulent contributions, the latter of which is given as a product of turbulent diffusivity in unburned gas and inverse scale of wrinkling at the leading edge. The bending behavior of U _T at higher u′ was successfully reproduced by the proposed expression. It is due to decrease in the inverse scale of wrinkling at the leading edge, which is related with an asymmetric profile of FSD with increasing u′. Good agreement is achieved between the analytical expression and the turbulent burning velocities from DNS throughout the wrinkled, corrugated and thin reaction zone regimes. Results show consistent behavior with most experimental correlations in literature including those by Bradley et al. (Philos Trans R Soc Lond A 338:359–387, 1992), Peters (J Fluid Mech 384:107–132, 1999) and Lipatnikov et al. (Progr Energ Combust Sci 28:1–74, 2002).     

Ferroelectrically Switching Helical Columnar Assembly Comprising Cisoid Conformers of a 1,2,3‐Triazole‐based Liquid Crystal

The 1,2,3‐triazole molecule, which is a product of click chemistry, possesses a high dipole moment and can be a useful polar motif for ferroelectric columnar liquid crystal (LC) materials—though it has not been used to date. Herein, we report the helical assembly and ferroelectric switching properties of a columnar liquid crystal comprising a naphthalene core and 1,2,3‐triazolyl linkages. The molecule assembles into a double‐stranded helical columnar LC structure (Col_hel). The X‐ray simulations of cisoid and transoid columnar models suggest that the helical assembly comprises cisoid conformers with a non‐zero dipole moment. The helical columns in the Col_hel phase are aligned homeotropically under an electric field. The ferroelectric switching of the axial polarization can be observed in the temperature range of 105–115 °C in the Col_hel phase, wherein the triazolyl hydrogen bonding along the column axis is weakened. The ferroelectric switching event is attributed to the rotation of the polar triazolyl units in response to the electric field.     

Accuracy evaluation of blood flow distribution in the Fontan circulation: effects of resolution and velocity noise

Journal of Visualization - This study analyzes the accuracy of the Fontan circulation using four-dimensional (4D) flow magnetic resonance imaging (MRI) for a variety of spatial resolution and noise...     

Anomalous magnetic properties of MnO nanoclusters

In this communication, we experimentally report, for the first time, that the MnO nanoclusters with cluster diameters of 5-10 nm show a ferromagnetic behavior with a phase transition from ferromagnetic to paramagnetic phases at 27 K even though their bulk phase is antiferromagnetic. We observed large coercivities up to 9500 Oe and a large remanence of 1.72 emu/g at 2 K, which are typically observed values for ferromagnetic materials. Although it is not clear, this abnormal ferromagnetic behavior of MnO nanoclusters may arise from cluster size effects.     

High-spin states in odd-odd 168Lu

High-spin states of odd-odd ¹⁶⁸Lu were observed up to 18ħ for the first time using the ¹⁵⁹Tb(¹³C, 4nγ)¹⁶⁸Lu reaction at E _13C= 58.5 MeV. γ-γ coincidence, E _γ singles, excitation function, and the DCO ratios were measured. Two rotational bands with signature splitting were populated, among which the lower-energy band is identified as π 7/2⁺[404] ⊗ν 5/2⁺[642] in view of alignment and energy systematics. Received: 27 October 1997     

Slope Estimates of Artin–Schreier Curves

Let X/F_p be an Artin–Schreier curve defined by the affine equation y ^p –y=f(x) where f(x)F_p[x] is monic of degree d. In this paper we develop a method for estimating the first slope of the Newton polygon of X. Denote this first slope by NP₁(X/F_p). We use our method to prove that if p>d2 then NP₁(X/F_p)(p–1)/d/(p–1). If p>2d4, we give a sufficient condition for the equality to hold.     

Accurate and Inaccurate Conceptions About Osmosis That Accompanied Meaningful Problem Solving

This study focused on the knowledge of six outstanding science students who solved an osmosis problem meaningfully. That is, they used appropriate and substantially accurate conceptual knowledge to generate an answer. Three generated a correct answer; three, an incorrect answer. This paper identifies both the accurate and inaccurate conceptions about osmosis of each correct and incorrect solver. The investigation consisted of a presolving clinical interview, think-aloud solving of the problem, and retrospective report of the solving. Of the 12 accurate conceptions identified here, two were especially important in enabling these solvers to generate a correct answer. Of the 8 inaccurate conceptions, either of 2 blocked a correct answer. Four, however, accompanied (and could therefore be concealed by) a correct answer. Teachers could use this information to make a meaningful solving of this problem accessible to more students and to identify more effectively students' inaccurate conceptions about osmosis.