Abstract: A recommendation guarantee system includes a first acquisition unit configured to acquire sequentially changing biological information on each of a plurality of providers providing a service, a storage unit configured to store a plurality of pieces of provider information including the biological information, the pieces of provider information respectively corresponding to the providers, a second acquisition unit configured to acquire request information on the service, and a selection unit configured to (i) extract an item related to an item included in the request information from the respective pieces of provider information as an environmental condition, and obtain a degree of reliability relating to each provider based on the biological information included in the respective pieces of provider information, and (ii) select the provider providing the service based on the request information, the environmental condition, and the degree of reliability.

Abstract: In a sleep quality estimation device, a respiration sensor detects the respiratory waveform of a subject. A sleep stage estimation unit estimates the sleep stage of the subject during sleep based on the respiratory waveform detected by the respiration sensor. In a sleep rhythm model database, models associated with the appearance probability of ?-wave for the sleep stage during sleep are recorded. A sleep quality estimation unit estimates the appearance time of ?-wave of the subject during sleep based on the sleep stage of the subject estimated by the sleep stage estimation unit and the models associated with the appearance probability of ?-wave for the sleep stage recorded in the sleep rhythm model database, and estimates the sleep quality of the subject based on the appearance time of ?-wave.

Abstract: In a sensor device which detects pressure variations owing to displacements of a body surface of a subject by respiration through variations of the output impedance of a piezoelectric vibrator, the pressure variations can be more efficiently transmitted to the piezoelectric vibrator. The sensor device, attached to a subject's body surface, comprises a contact piece contacting the body surface; a displacement-signal convertor which converts the displacements of the body surface into electrical signals; and an outputting device which outputs the electrical signals to an external unit; the sensor device is clamped between the body surface of the subject and an upper edge portion of a subject's bottom garment, and the contact piece is arranged in one side surface of a housing, and a stopping member which can be attached with the upper edge portion of the bottom garment in the other side surface of the housing.

Abstract: In a sensor device which detects pressure variations owing to displacements of a body surface of a subject by respiration through variations of the output impedance of a piezoelectric vibrator, the pressure variations owing to displacements can be more efficiently transmitted to the piezoelectric vibrator. The sensor device, attached to a subject's body surface and detecting displacements of the body surface accompanying respiration of the subject, comprises a contact piece having a contact surface which contacts the body surface when the sensor device is attached to the body surface; a displacement-signal convertor which is connected with the contact piece and converts the displacements of the body surface into electrical signals; and an outputting device which outputs the electrical signals to an external unit; wherein the contact surface of the contact piece is a curved surface projecting outward in a direction from its periphery to its center.

Abstract: In a sleep quality estimation device, a respiration sensor detects the respiratory waveform of a subject. A sleep stage estimation unit estimates the sleep stage of the subject during sleep based on the respiratory waveform detected by the respiration sensor. In a sleep rhythm model database, models associated with the appearance probability of ?-wave for the sleep stage during sleep are recorded. A sleep quality estimation unit estimates the appearance time of ?-wave of the subject during sleep based on the sleep stage of the subject estimated by the sleep stage estimation unit and the models associated with the appearance probability of ?-wave for the sleep stage recorded in the sleep rhythm model database, and estimates the sleep quality of the subject based on the appearance time of ?-wave.

Abstract: A stimulatory effect estimation device includes a stimulus generator 3 which applies a stimulus to a back seat passenger, an electroencephalogram 2 which measures the brain waves of the back seat passenger, a memory 4, and an ECU 5 which specifies the brain wave indexes of stimulatory effects which surface in response to the stimuli both when the passenger is awake and when the passenger is asleep from the brain waves measured by the electroencephalogram 2 when a stimulus is applied from the stimulus generator 3 while the passenger is awake and the brain waves measured by the electroencephalogram 2 when a stimulus is applied from the stimulus generator 3 while the passenger is asleep.

Abstract: A method of monitoring variation in either or both respiration and heartbeat of an animal comprising the steps of vibrating a piezoelectric vibrator by continuously or intermittently applying an AC voltage of a frequency corresponding to a natural resonance frequency of the vibrator to the piezoelectric vibrator under such condition that the vibrator is placed directly or indirectly in contact with the surface of the animal's body; collecting a current generated by the vibrator under vibration; and calculating an impedance of the vibrator from a value of the current and a value of the AC voltage applied to the vibrator so as to continuously or intermittently detect variation of the impedance by lapse of time is effective to monitor variation of respiration and/or heartbeat of animals including humans who are in sleep or under exercise and take a variety of positions with high sensitivity.

Abstract: Since a change in a heart beat is dominated by the autonomic nerve which originates in the brain stem, it is difficult for an object person to control the heart beat at his or her own will. Therefore, frequency analysis, such as fine fluctuation analysis, is needed in order to estimate the body motion of the object person and is not suitable for instant processing. In contrast, according to this embodiment, an arithmetic unit 30 of a sleep state estimation device 1 estimates the state of the object person on the basis of the identity of each cycle of a breathing waveform of an object person M as the feature amount of the breathing waveform. The object person M can control a change in breathing at his or her own will.

Abstract: A stimulatory effect estimation device includes a stimulus generator 3 which applies a stimulus to a back seat passenger, an electroencephalogram 2 which measures the brain waves of the back seat passenger, a memory 4, and an ECU 5 which specifies the brain wave indexes of stimulatory effects which surface in response to the stimuli both when the passenger is awake and when the passenger is asleep from the brain waves measured by the electroencephalogram 2 when a stimulus is applied from the stimulus generator 3 while the passenger is awake and the brain waves measured by the electroencephalogram 2 when a stimulus is applied from the stimulus generator 3 while the passenger is asleep.