Abstract: An alertness device includes: a respiration sensor that obtains respiratory data of a person; a calculation unit; a waveform generation unit that generates a respiratory interval (RI) waveform which is a transition in a predetermined time period of an RI which is an interval for one respiration; and a determination unit. The calculation unit calculates an average value of the RI and RrMSSDn in a predetermined time period. In a case where an average value of the subsequent RI is greater than an average value of the RI directly previous to the subsequent RI and in a case where the RrMSSDn of the subsequent RI is greater than a value which is obtained by multiplying the RrMSSDn of the previous RI by a constant ?, the determination unit determines on the basis of values calculated by the calculation unit that the person is in a state of low alertness.

Abstract: A wakefulness-maintenance apparatus applies a stimulus, which is not perceived to be unpleasant to most seated persons, to a seated person, and effectively maintaining the wakefulness of the seated person. After a control device provided to the wakefulness-maintenance apparatus stimulates the seated person using a first stimulus at a timing close to a human heartbeat, if an index showing the wakefulness of the seated person departs within a predetermined time from a standard indicating that the wakefulness has been maintained, the control device drives a stimulus device to stimulate the seated person using a second stimulus having a timing that differs from the first stimulus.

Abstract: An alertness device includes a heart rate sensor configured to obtain an electrocardiographic signal of a person, a calculation unit configured to calculate the electrocardiographic signal obtained from the heart rate sensor, a waveform generation unit configured to generate an RRI waveform from an electrocardiographic waveform of the electrocardiographic signal, and a determination unit configured to determine the alertness of the person based on the electrocardiographic signal. The calculation unit replicates a same number of RRI waveforms as that of anchors, each anchor being a point where a certain RRI is shorter than an adjacent preceding RRI, moves the time axes of the replicated RRI waveforms such that the anchors of the replicated RRI waveforms are in phase with each other, and calculates a PRSA signal defined as an RRI average for each time axis. The determination unit determines the alertness based on the RRIs and the PRSA signals.

Abstract: An alertness device includes: a respiration sensor that obtains respiratory data of a person; a calculation unit; a waveform generation unit that generates a respiratory interval (RI) waveform which is a transition in a predetermined time period of an RI which is an interval for one respiration; and a determination unit. The calculation unit calculates an average value of the RI and RrMSSDn in a predetermined time period. In a case where an average value of the subsequent RI is greater than an average value of the RI directly previous to the subsequent RI and in a case where the RrMSSDn of the subsequent RI is greater than a value which is obtained by multiplying the RrMSSDn of the previous RI by a constant ?, the determination unit determines on the basis of values calculated by the calculation unit that the person is in a state of low alertness.

Abstract: An alertness device includes a heart rate sensor configured to obtain an electrocardiographic signal of a person, a calculation unit configured to calculate the electrocardiographic signal obtained from the heart rate sensor, a waveform generation unit configured to generate an RRI waveform from an electrocardiographic waveform of the electrocardiographic signal, and a determination unit configured to determine the alertness of the person based on the electrocardiographic signal. The calculation unit replicates a same number of RRI waveforms as that of anchors, each anchor being a point where a certain RRI is shorter than an adjacent preceding RRI, moves the time axes of the replicated RRI waveforms such that the anchors of the replicated RRI waveforms are in phase with each other, and calculates a PRSA signal defined as an RRI average for each time axis. The determination unit determines the alertness based on the RRIs and the PRSA signals.

Abstract: A wakefulness-maintenance apparatus applies a stimulus, which is not perceived to be unpleasant to most seated persons, to a seated person, and effectively maintaining the wakefulness of the seated person. After a control device provided to the wakefulness-maintenance apparatus stimulates the seated person using a first stimulus at a timing close to a human heartbeat, if an index showing the wakefulness of the seated person departs within a predetermined time from a standard indicating that the wakefulness has been maintained, the control device drives a stimulus device to stimulate the seated person using a second stimulus having a timing that differs from the first stimulus.

Abstract: A sleepiness assessment value P1 is set to be an average heart rate HR (S130). A sleepiness assessment value P2 is set to be a standard deviation ? of a respiration interval RespI for one minute (S150). A sleepiness assessment value P3 is set to be a value that is obtained by dividing, by one minute, an integrated value of a square of an average heartbeat interval RRIavg in a case where a variation in which a heartbeat interval RRI increases occurs (in a case where an RRI count value Xi is a value of one) (S190). A sleepiness assessment value P4 is set to a value that is obtained by averaging a variation ratio in a case where a variation in which the respiration interval RespI increases occurs (in a case where an RRI count value Yi is a value of one) (S210).

Abstract: A sleepiness assessment value P1 is set to be an average heart rate HR (S130). A sleepiness assessment value P2 is set to be a standard deviation ? of a respiration interval RespI for one minute (S150). A sleepiness assessment value P3 is set to be a value that is obtained by dividing, by one minute, an integrated value of a square of an average heartbeat interval RRIavg in a case where a variation in which a heartbeat interval RRI increases occurs (in a case where an RRI count value Xi is a value of one) (S190). A sleepiness assessment value P4 is set to a value that is obtained by averaging a variation ratio in a case where a variation in which the respiration interval RespI increases occurs (in a case where an RRI count value Yi is a value of one) (S210).