In intelligent vehicle and highway systems (IVHS), lateral and headway vehicle control is used to maintain stable driving. Headway control keeps the controlled vehicle an appropriate distance from vehicles directly ahead. Each vehicle needs to have an obstacle detection system installed to monitor distances to the preceding vehicle and its relative speed.In the future, headway control systems for consumer use must be cheap and capable of operating in all environmental conditions. To enable such equipment to be built, a dual mode millimeterwave radar has been proposed. It would be able to operate in both radar mode, in which it would measure the distance to the leading vehicle, and in communication mode, in which it would exchange data with a vehicle ahead of it. By operating in two modes alternately, the dual mode radar can provide the headway control system with all the data needed to control the distances to the leading vehicles, their speeds, acceleration conditions, and the leading vehicle's steering angle and brake signal. The data can then be used for stable control of the vehicles. This paper describes the concept of the dual mode radar systeim and the results of the experiments undertaken.

In this study, a new method of noninvasive sensor system is developed to detect mechanical stresses induced in minute living cells and tissues. The bending mode of vibration, excited impulsively by piezoelectric ceramics, is utilized in a small clamped-free beam type vibrator which is mounted on micromanipulator system. Experimental studies have been carried out by using living egg cell of killifish and also three dimensionally tissue-engineered regenerated cartilage. The method has shown enough capabilities as a micro-sensor to detect mechanical stresses which are environmentally induced in living cells. Also, it has suggested a possibility to provide useful information to decide whether three dimensionally cultured cartilage tissue has enough biomechanical properties for transplantation treatment of damaged cartilage.

As one of the cellular responses to external mechanical stimulation, it is presumable that the cell adjusts the cytoskeletal mechanical strength globally as well as locally. However, the methodologies to validate this hypothesis are extremely limited and expensive. In this study, a new micro device, utilizing dynamic response of a piezoelectric vibrator, is developed, which works not only to evaluate local mechanical property, but also to enforce local mechanical stimulation onto cultured living adhesive cells. Experimental studies have been carried out by applying actin (the major component of cytoskeleton) polymerization inhibitor, cytochalasin D, to normal human osteoblast. The studies show the present device's sensing capability to detect changes of mechanical property, induced by external mechanical stimulation, of cultured normal human osteoblast. Also, the method shows that the cellular response against static and dynamic mechanical stimulation differs depending on the condition of actin cytoskeleton.

In this study, a new three-dimensional micro vibration stage is developed, in which a doubly steric L-shaped clamped-free beam type vibrator is utilized. The developed three-dimensional micro vibration stage, which has very simple structure and is quite easily sterilized, is extended to control system of cell culture. Focusing on osteoblast character which is sensitive to external mechanical stimuli, a normal human osteoblast is chosen as a test subject. Dynamic stimulation is applied to the normal human osteoblast utilizing the developed three-dimensional vibration stage. In order to estimate effect of dynamic stimulation upon cultured cell, we define parameters of projected area and slenderness ratio of the cultured normal human osteoblast. Statically cultured cells of 4th and 6th passage were provided for experiments. It was observed that the projected area of normal human osteoblast increased, while the slenderness ratio decreased according to the number of cell passage increasing. Shape of the 6th passage of dynamically stimulated cells was not similar to that of same passage of control, but to that of 4th passage of control. From the viewpoint of morphology, the present study has shown the significant effect of dynamic stimulation upon cultured cells.

No abstract