Slow eye movement as a possible predictor of reaction delays to auditory warning alarms in a drowsy state

In recently developed intelligent vehicles, warning alarms are often used to prompt avoidance behaviours from drivers facing imminent hazardous situations. However, when critical reaction delays to auditory stimulation are anticipated, the alarm should be activated earlier to compensate for such delays. It was found that reaction times to an auditory stimulus significantly increased in the presence of slow eye movement (SEM), which is known to occur frequently during the wake-sleep transition. The reaction delay could not be attributed to temporal effects such as fatigue and was invariant regardless of response effectors (finger or foot). Moreover, it was found that applied pedal force decreased immediately after an auditory stimulus interrupted SEM. Consequently, it was concluded that SEM can be a good predictor of reaction delays to auditory warning alarms when drivers are in a drowsy state. STATEMENT OF RELEVANCE: The present study demonstrated that simple auditory reaction time significantly increased when SEM emerged. In the design of vehicle safety systems using warning alarms to prompt avoidance behaviours from drivers, such reaction delays during SEM must be taken into account.     

Three-dimensional scanner of a pipe with tilt detection

The 3D quantitative measurement system for a sewer pipe is introduced. Two parallel lasers are rotated by the motor and draw the two annular streaks on the inside surface of the pipe. The circular laser streaks are recorded by the CCD camera. The measurement of the cross-section is established by analyzing the recorded streaks. The tilt of the robot against the axis of the pipe is detected by the deviation between two parallel lasers. It enables us to measure the vertical cross section of the pipe regardless the tilt of the system to the pipe. Experimental result shows the feasibility of the system. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Learning Monotone Log-Term DNF Formulas under the Uniform Distribution

Based on the uniform distribution PAC learning model, the learnability for the class of monotone disjunctive normal form formulas with at most O (log n ) terms, denoted O (log n )-term MDNF, is investigated. Using the technique of restriction, an algorithm that learns O (log n )-term MDNF by examples in polynomial time is given. Received February 2, 1998, and in revised form April 8, 1999, and in final form June 30, 1999.     

Switching in polystyrene and polymethyl methacrylate thin films: effect of preparation conditions of the polymers

Switching without any break in the electrodes was observed in polystyrene and polymethyl methacrylate films by controlling the current using a high resistance connected in series with the sample. The effect of the method of polymerization on the switching characteristics were studies for both polymers. Polymers were prepared by -ray irradiation or by catalytic or noncatalytic thermal polymerization. The switching characteristics gave poor reproducibility for the catalytically polymerized polystyrene, but no difference was observed for the three types of polymethyl methacrylate from different origins. In the case of polystyrene, the lower the molecule weight, the higher was the threshold voltage. With polymethyl methacrylate such a dependence was not observed. In both polymers the on-state is relatively stable. When the samples in the on-state were heated above 100° C, they were converted to the offstate. No dots or breaks on the sample were detected by scanning electron microscopy (SEM) after switching has occurred.     

Fatigue behaviour of precipitation-hardening medium C steels containing Cu

The presence of Cu precipitates counteracts the cyclic softening present in ordinary quenched and tempered steels. This is expected to result in an increase in fatigue limit. The fatigue crack propagation rate (dc/dN) at constant K in the Cu-C steels was shown to depend on heat-treatment and carbon content. To maximize yield strength and minimize ¦da/dN¦_K for tempering at 500° C, one must choose a low C content and temper for a short time; ¦da/dN¦_K in 0.28 wt % C-1.45 wt % Cu tempered for 13 min was one-third that for 0.45 wt % C-1.45 wt% Cu tempered for 200 min. There is also an advantage in adding Cu while simultaneously lowering the Ccontent. The dc/dN data are discussed in terms of the yield strength and the energy to form a unit area of fatigue crack, U, which was measured using foil strain gauges. The quantity (¦dc/dN ¦_{K y} ² U) where _y is the cyclic yield stress, was found to be nearly constant. In the 0.28 wt % C-1.45wt % Cu alloy, short ageing times at 500° C resulted in greater resistance to initiation of cracks at notches for low Ks than long ageing times.     

Development of revolving drop surface tensiometer

A revolving drop surface tensiometer, which measures the surface tension of a small amount of liquid, is proposed. A remarkable feature of this device is that while using the pendant drop method, it employs a centrifugal force to deform the liquid droplet. The centrifugal force induces a large distortion of the droplet, which enables an accurate measurement of the surface tension to be made. In our experimental setup, the centrifugal force can be increased so that the apparent acceleration becomes up to 100 times larger than that due to gravity, and the capability of this method to measure surface tensions was demonstrated with ethylene glycol.     

Pressure wave propagation in air-water bubbly and slug flow

Related to nuclear reactor safety problems, such as the loss of coolant accident caused by some small crevasses in nuclear reactor, choked flows after postulated breaks of hot and cold legs of pressurized water reactors and the boiling flow instability in parallel channels, the characteristics of pressure wave propagation were investigated experimentally for the air-water bubbly and slug two-phase flow in a vertical pipe. Pressure wave was generated from the small pressure disturbance by the up-and-down movement of piston in the test section. Air void fraction was up to 0.7 and superficial liquid velocity was up to 1.5 m/s as experimental conditions. The experimental results show that the pressure wave propagation velocity in bubbly flow decreases acutely with the increase of air void fraction from 0 to 0.05. In slug flow, it is constant when the air void fraction is less than 0.5 but increases gradually when the void fraction increases beyond 0.5. The attenuation coefficient of pressure wave increases with the increase of air void fraction in bubbly flow. The dependency of pressure wave propagation velocity on angle frequency ω in air-water flow shows the dispersion characteristic. The propagation velocity and attenuation coefficient increases gradually with the increase of angle frequency. However, the increase vanishes slowly as the angle frequency reaches 250 Hz in bubbly flow. The propagation of pressure wave in bubbly flow is independent of the superficial velocity of fluids in the range of experiment.     

Development of specimen and test method for strength analysis of MEMS micromirror

Specimens and fracture test methods for strength analysis of MEMS micromirrors were proposed. Bending and combined loading tests were performed, and torsion strength was estimated from those results. Two-parameter Weibull distribution was used to evaluate the fracture stresses estimated from the FEM model. The resulting scale and shape parameters were 787 MPa and 7.77 for the bending test and 517 MPa and 5.28 for the combined loading test. There was a difference in strength between the results of the bending and combined loading tests. From the load factor analysis, it was found that both geometry and stress distribution have to be considered to estimate the strength of MEMS since flaws are non-uniformly distributed. It was also found that torsional strength can be estimated on the safe side using the results of the combined loading test.     

共析钢中片层状渗碳体冷轧后的形态变化

The pearlitic transformation and the deformation behavior of lamellar cementite after cold rolling in eutectoid steels Fe-0. 76%C-0. 137%Mn (mass fraction) were studied by means of Formastor-F (Full Automatic Transformation Testing Instrument) and field emission scanning electronic microscopy (FESEM) observation. Fine and coarse pearlite were obtained in the eutectoid steels austenitized at 900℃ for 15min, then hold at 620℃ for 90 s and 690℃ for 7 h, respectively. Thedeformation behavior of cold rolled lamellar cementite could be classified as: cleavage fracture, inhomogeneous slip, fragmentation, thinning or necking, and homogeneous bending. The cementite lamellae with the thickness of more than 100 um could be deformed plastically.