タイトルロゴ
事業紹介

カオスとは
Chaos refers to a phenomenon whose behavior is extremely complex, erratic and unstable and is incapable of predicting the state of the far future, despite the generation system of the phenomenon is based on a set of firm rules (deterministic rules). There are 5 characteristics that make up the properties of chaos:

1.
Sensitive to initial values (replication by controling initial values is very rare)
2.
Hold a wide power spectrum with no distinct shape in frequency components
3.
Neighboring orbits passing the subspace of the attractor are approximately in the same direction
4.
Correlation function rapidly becomes zero along with time
5.
Largest Lyapunov exponent is positive
6.
Have a non-integer fractal dimension
Characteristics of 2, 4, 5 and 6 are also found in random signals. The characteristic of 3 is also found in quasi-periodically signals.

生体情報とカオス

Cannon's "homeostasis" is said the basic principle in physiology that pursues the principles of life phenomena.
Homeostatis is a term coined from the Greek words of homeo meaning "the same" and statis meaning "the state" by Walter B. Cannon, an American physiologist, and refers to the function that maintains the composition and the physical conditions of the living body at a constant state. It has been said that homeostatis should be preserved  for a living body to maintain life and there was an automatic adjustment feature made from a negative feedback circuit within the body.
When applying the concept of homeostatis to vital signs (such as heart rate, respiration, blood pressure and body temperature whose are directly related to the maintenance of life), it was thought that there was a feedback mechanism in a human body, which compensate for any outside disturbance that causes deviation from a constant state (normal values), and the more these values were stable, the more the control system of a living body was functioning well . However, the fact is even when a human is lying still, the beating interval of his/her heart is not constant, and shows considerable erratic fluctuations (heart-rate fluctuation). Respiration, blood pressure and body temperature are also the same. About heart-rate fluctuations, It is known that elder humans and sick humans have less fluctuations.
In the field of physiology, from the mid of the 1980's, there was a flurry of reports indicating that biological signals such as heart-rate fluctuations and brain waves may be chaotic. And a review of chaos (T. Elbert, W. J. Ray, Z. Kowalik, J. E. Skinner, K. E. Graf and N. Birbaumer, Physiol. Rev. 74 (1994) 1) was published in Physiological Review, an authoritative magazine in the field of physiology . In the field of physiology, research on chaos is getting common .


生体情報計測・・・『揺らぎ』の測定について

指尖容積脈波の測定

Bio-information of the human body is called vital signs and include body temperature, blood pressure, pulse rate, etc. As the vital sign to use, we measure the amount of blood flowing in the vessels at the fingertip, and construct time-series waves from it. The advantage of using a fingertip rather than a heart, is that fingertip pulse waves contain more information such as the nerve system than heart pulse waves. This is because fingertips locate at the end of the body. The measured vital signs show so complex (chaotic) behavior that we use nonlinear (chaos) analysis and calculate Lyapunov exponents from the measured waves.

測定で何がわかるか

It is said that physical immunity is important for human beings to maintain health, and declining in physical immunity cause various illnesses. We defend ourselves against declining in physical immunity by many ways as proper eating habits, adequate rest, medicine and physical exercise. On the other hand, even though mental immunity is also extremely important for human beings, there was no way to measure our mental immunity in the past. However, as the result of our psychological and bio-informatics research, we found the value of Lyapunov exponents of the fingertip plethysmogram and the mental immunity are closely related as described below.

精神的免疫力

Mental immunity refers to human's adaptability, communication skill, ability of self-expression, flexibility of the mind, etc. against changes in the environment we face throughout our lives. To maintain our lives, we human beings skillfully manage various changes, encounters and attacks through adaptation, engagement, handling and self-expression. Those are exactly the effectiveness of the mental immunity. Mental immunity is one of the most important index for the human life. Mental immunity dynamically changes time by time based on his/her condition and emotion such as delight, anger, sorrow and pleasure. The mental immunity dynamically fluctuates in occasions such as, for example, when you concentrate on work or lose concentration, when you are strongly motivated, when you are uncomfortable to communicate with a certain type of people or when you enjoy communication with people you like. It can be said that he/she has high mental immunity when one can motivate and drive oneself to perform a difficult task. The value of mental immunity (the Lyapunov exponents value) is used to fluctuate dynamically. Permanently high or permanently low state of mental immunity with no fluctuation can be said an abnormal condition for human being. Excessive tension or stress will show a continuous high value. On other hand, state of dementia caused by depression or aging will show a continuous low value. Up to now, we have reported a various of researches about relationship between the mental immunity and the Lyapunov exponents. Among these are, correlation between lower values in the Lyapunov exponents and lesser communication skill caused by aging or progression of dementia, relationship between the Lyapunov exponents and work errors, verification of the mental turning point of 3 year old children seen in worldwide in respect to the Lyapunov exponents values. As the result of our researches, it can be said for human beings that our mental immunity is desirable to have constantly moderate fluctuation regardless of the age.
Just as one becomes ill when one lose physical immunity, The mental immunity may be considered as a synonymous word of the "vitality of the mind" whose term was a vague sense up to now. The "vitality of the mind" have not been able to quantitatively measure, but now we believe it can be grasped by measuring the "fluctuation" using the Lyapunov exponents.

研究紹介

Our prime purpose of research is to establish ways that allow us to scientifically explore human life and body. By focusing on the chaotic characteristics of human beings, we have now two major research themes such as the relationship between cognitive psychology and fluctuation of bio-information measured by the Lyapunov exponents values, and relationship between visual impressions and presented picture image. In order to fulfill our research, we have adopted data mining and text mining as methods for analyzing experiment and survey data.
For the first theme, we have developed a system that calculates and displays fluctuation values of pulse waves using chaos analysis, and also a graphical presentation system and a database system for further grasping the fluctuation in long term. These systems are used to conduct researches to explore relationship between bio-information and various fields such as the anxieties or depressions of working people, the growth of children, affection of mothers/problem behavior of children, human emotion caused by scent, music and laugh, and so on. We also have a plan to develop a compact device that is user friendly and handy to carry so that anyone and at anywhere can measure pulse waves. Our plan of development and sales of such a device is with manufacturing partners and sales partners. For the accumulation of data, our plan is to develop a database in Internet with companies who have rich of experience and skill about data security. Cellular phones is also one of our target of platform.
The research of our second theme is focused on human's sight. we pursue the way to measure from image data how much these images give human good impression. We conducted researches on relationship between human's preferable impression and the fractal dimensions of presented picture images. 
With our two research themes, we expect our researches will be applied in variety of fields including welfare/nursing care, psychotherapy, child growth and education.

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