Kouichi Yamada

Monolithic uncooled infrared image sensor with 160 by 120 pixels

This paper presents the key design features of an uncooled infrared image sensor with 160 by 120 pixels. This sensor has a monolithic structure using micromachining technology. These features concern the configuration of the readout circuit, the structure of the infrared detector, and the thermal isolation structure in a pixel. The first feature is a simple readout circuit that includes neither an amplifier nor a switching transistor in the pixel. The second feature is the use of a thin film resistive bolometer made of polysilicon as the infrared detector. The detector has a P+-P--N+ diode structure which operates as a bolometer and cuts off current passes through non-selected pixels. The forward resistance of the diode can be tailored by adjusting the shape and impurity concentration of the P- region. Finally, a microbridge structure for the thermal isolation is made in each pixel by using the micromachining technology. The bolometer is monolithically integrated on this structure. Since polysilicon is generally used in the conventional Si-LSI process, this choice of detector material makes it possible to manufacture the image sensor using only current Si-LSI facilities, and realize a low cost uncooled infrared camera.

Pit Shape At Overwriting Of Thermal Magneto-Optical Recording

The pit shape in magnetic field modulation recording is obtained from temperature profile which is calculated by using three dimensional thermal diffusion equations considering the movement of laser spot. The pit edge shape changes more elliptically with increasing disk velocity. The calculated frequency response does not degrade so much as the pit edge shape changes. The influence of disk velocity to the frequency response is less than that of recorded pit duty. These calculation method is useful for obtaining the recording characteristics of read-write channel, when various parameters are changed, without experiments.

Motion control of tumbling spacecraft by repetitive impulse inputs

An angular momentum control of a tumbling spacecraft by applying repetitive impulses from a space robot arm is discussed. By assuming inputs by the arm, the direction, size and timing of the input forces are relatively free to choose. At each control cycle, however, torques parallel to the contact direction cannot be generated. Therefore, the design of controller is not straightforward. To solve this difficulty, the equations of rotational motion are rewritten into simpler forms by applying appropriate coordinates transformation. Then a discrete controller is designed so that the component of the. angular momentum parallel to the contact direction is damped out by choosing the directions of input forces properly. Numerical simulations are given to show that the angular momentum is efficiently damped.

Interchangeability of optical disks

The aim of this study is to improve interchangeability to ISO standard optical disks. The compensation of the write condition and the expansion of dynamic range of servo circuits using control track data have been tried. The results were satisfactory.

Productivity Improvement and Stress Reduction by Showing Information to a Surveillance Worker

System surveillance is a function required for continuous operation of a system which consists of various apparatus and networks. Many service providers try to raise their productivity. Their methods show some information to a surveillance worker after the alarm occurs. As another method of the rationalization, a surveillance system shows some information to the worker on the waiting time. The simulated environment of surveillance has been built. There are three kinds of screens that are shown to the subject on waiting state. Passive case test uses passive waiting screen that displays no information. Directed case test uses directed waiting screen that displays operation method. Active case test uses active waiting screen that displays list of surveillance objects and can be scrolled by subject. Subjects’ stress are performed by R-R interval. By comparing 12 subjects, it was confirmed that they are working efficiently in the test which display some information, and active case test that encourages voluntary browsing allows subjects to relax. It is an effective method of a productivity improvement and stress reduction to display the information that encourage voluntary browsing on waiting time.

Evaluation of the Productivity Improvement by Information Presentation in Surveillance Service

System surveillance is a function required for continuous operation of a system which consists of various apparatus and networks. Many service providers try to raise their productivity. Their methods are to show some information to a operator after alarm occurs. As another method of the rationalization, a surveillance system shows some information to the operator in the waiting time. We have built the simulated environment of surveillance and compared 12 subjects. Operators are working efficiently most in the type which displays the information. It is an effective method of a productivity improvement to display the information on waiting time.

Productivity improvement and stress reduction by the information presented to workers

System surveillance is a function required for continuous operation of a system which consists of various apparatus and networks. Many service providers try to raise their productivity. Their methods are to show some information to a operator after alarm occurs. As another method of the rationalization, a surveillance system shows some information to the operator in the waiting time before alarm occurs. This study evaluates the difference in productivity and stress of the work by way of the use of the waiting time. This will reveal the appropriate usage of waiting time. We have built the simulated environment of surveillance system and compared 12 subjects. Operators are working efficiently most in the type which displays the information. Display of information about the indication of operation is enhanced subjects of stress. Display of information to encourage voluntary browsing is allowed to relax the subject. It is an effective method of a productivity improvement and stress reduction to display the information that encourage voluntary browsing on waiting time.

The effect and reaction of information presentation in surveillance services

Surveillance services are passive work. The surveillance operators are continuously waiting for an alarm. By adding active work to waiting time, the alarm process and disposal time of surveillance operator becomes short. We built a simulated environment of surveillance, and compared physiological reaction of subjects whose experiences were different. As a result, alarm disposal time is shortened in cases where active work was added. The physiological reaction of the subject with a small amount of experience shows little difference both cases. The subject with large amounts of experience shows high tension and little stress in the case of adding active work. We conclude that adding active work to surveillance improves the productivity of surveillance service and to stabilizes the work in the surveillance operator with many amounts of experiences.