Sequential Inverse Optimal Control of Discrete-Time Systems

This paper presents a novel sequential inverse optimal control(SIOC)method for discrete-time systems,which calculates the unknown weight vectors of the cost function in real time using the input and output of an optimally controlled discrete-time system.The proposed method overcomes the limitations of previous approaches by eliminating the need for the invertible Jacobian assumption.It calculates the possible-solution spaces and their intersections sequentially until the dimension of the intersection space decreases to one.The remaining one-dimensional vector of the possible-solution space’s intersection represents the SIOC solution.The paper presents clear conditions for convergence and addresses the issue of noisy data by clarifying the conditions for the singular values of the matrices that relate to the possible-solution space.The effectiveness of the proposed method is demonstrated through simulation results.

On Decay of Solutions and Spectral Property for a Class of Linear Parabolic Feedback Control Systems

Unlike regular stabilizations, we construct in the paper a specific feedback control system such that u(t) decays exponentially with the designated decay rate, and that some non-trivial linear functionals of u decay exactly faster than . The system contains a dynamic compensator with another state v in the feedback loop, and consists of two states u and v. This problem entirely differs from the one with static feedback scheme in which the system consists only of a single state u. To show the essential difference, some specific property of the spectral subspaces associated with our control system is studied.

The Effect of Traction Position in Cervical Traction Therapy Based on Dynamic Simulation Models

This study describes the development of a cervical traction therapy simulation model that evaluates two types of the traction positions, namely the sitting position and the inclined position. An anatomically correct human skeleton model and two mechanical traction device models were constructed in simulations using a physics engine. The anterior and posterior intervertebral separations were measured at both positions with a series of traction forces (60N to 200N) and traction angles (10°? to 40°?). The result suggested that the sitting position caused the subject to lean forward and as a result led to excessive anterior compression when traction angle is over 20 degrees. The inclined position creates greater intervertebral separations on both the anterior and posterior sides than the sitting position. This suggests that the inclined position may be more effective in increasing intervertebral separation than the sitting position.

Measurement and Evaluation of the Autonomic Nervous Function in Daily Life

We developed a smart-phone based system to measure the activities of autonomic nervous system during everyday life. Using commonly marketed smart phones, by touching your fingertips on the phone’s camera over a short time of about 30 seconds, it will detect changes in the brightness of the blood flow and in turn analyze your heart rate variability. By using this system, about 100,000 cases were measured and from this large amount of data regarding heart rate variability, we evaluated the autonomic nervous function in their daily life. As a result, for the correlation between autonomic nervous system and age, we found that as the increase of age, the total power becomes decreased and the sympathetic nervous system tends to increase between thirties and fifties. For the correlation between autonomic nervous system and BMI (Body Mass Index), it is found that in general, the higher the BMI, the lower the total power and the stronger the sympathetic nervous system. In other words, people who are fat are lower about the total power and stronger about the sympathetic nervous system. In addition, for the correlation between autonomic nervous system and one day life, it is found that total power and sympathetic function tend to increase, while as evening approaches, sympathetic function tends to become suppressed.

Activation of Human Prefrontal Cortex to Pleasant and Aversive Taste Using Functional Near-Infrared Spectroscopy

The aim of the study was to investigate the representation of taste in human prefrontal cortex (PFC), in particular, to compare the representation of a pleasant and an aversive taste using functional near-infrared spectroscopy (fNIRS), so as to obtain further understanding of the taste preference mechanism. The pleasant stimulus used was sweet taste (10% sucrose), and the unpleasant stimulus was sour taste (1% critic acid). Based on event-related design, the experiments were performed with 16 healthy volunteers using the OEG-16 fNIRS sensor. A general linear model was used to analyze the collected data. For the concentration change of oxygenated hemoglobin (ΔoxyHb), we found that significant deactivation was induced by sweetness and sourness in parts of the frontopolar area, orbitofrontal area and dorsolateral prefrontal cortex in bilateral hemisphere of human brain. And the right PFC showed different levels of activation between sweetness and sourness. In addition, brain activities were more sensitive to sourness than sweetness. Finally, we confirmed that the PFC was involved in sweet and sour taste processing, and fNIRS provided an alternative way for studying taste-related brain function under more natural conditions.

Experiment and Dynamic Simulation of Cervical Tractions in Inclined and Sitting Positions

This study aims to validate the accuracy of a cervical traction therapy simulation model by comparing the intervertebral separations of six asymptomatic male adults when traction was applied to their cervical spines. The subjects were tested on two mechanical traction devices, representing the inclined and sitting positions. A total of 55 radiographic images of their cervical spines were taken before and during traction. The result showed statistically significant intervertebral space changes in the inclined position but the changes in the sitting position were not statistically significant. The observed changes of the cervical spine were used to adjust parameters of the traction therapy model, which contains a human model with cervical spine built with springs and dampers and two traction devices in inclined and sitting positions. A series of traction forces and traction angles were applied to the model to simulate the actual parameters used in the experiment and the new model was used to evaluate the two traction positions. The result suggested that inclined position creates greater intervertebral separations on the posterior sides. Differences in separations due to age were not observed in both positions. The result also suggested that the inclined position provides better control in positioning the separations at different spinal segments than the sitting position.

Integrated GIS, Remote Sensing and Survey Data for Damage Assessment of Buildings in Tsunami Event, Ishinomaki City, Japan

The 2011 Tsunami event in the eastern coastal area of Japan caused a huge amount of damages or devastations on buildings. To this date, several field surveys have been conducted which provide detailed information about inundation areas and building damage characteristics in attacking east coastal areas by this tsunami. In this study, building damage data of Ishinomaki city, with special attention to the plain coast affected area, are classified and analyzed using data surveyed by the Ministry of Lands, Infrastructure and Transportation of Japan (MLIT) for more than 52,000 structures. The classification includes information on six levels of damage, four types of building materials and damages due to tsunami inundation for each building material which are necessary information for an effective hazard mitigation. Notably, damage level percentage distribution of different building materials is plotted for different inundation depth ranges in several sets of figures. This graphic illustration not only shows a better resistant performance of Reinforced Concrete (RC) and steel buildings over wood or other buildings for all inundation depth ranges, but also can explain clearly the inundation-induced damage behavior for each building material as well as the threshold depth for each damage level. Moreover, this research contains an analysis of vulnerable areas due to the coastal topography and the geographical factors. Surveyed data provided by Geospatial information authority of Japan (GSI) that classifies Ishinomaki plain coast area into three classes are compared with the damage map produced using an Analytical Hierarchy Process (AHP) methodology in ArcGIS 10.2 environment. The influence of key geographical features on tsunami-induced building damage, notably Kitakami river and water canals flooding, is taken into account with respect to the weighting of factors. A good agreement produced building damage map with surveyed GSI data shows the power of a GIS tool based on the AHP approach for tsunami damage assessment. The results of this study are useful to understand the damage behavior of buildings with different structural materials located in coastal areas vulnerable to the tsunami disaster.

On Energy-based Robust Passive Impedance Control of a Robot Manipulator

Passivity is an important requirement for a robot to interact with human or other dynamic environments stably and safely as in robotic rehabilitations. Considering the time-varying objective impedance center, under the condition that the robot＇s dynamics is known, previous research has already proposed a passive impedance control approach which adjusts a scaling parameter of the robot＇s desired velocity with respect to the robot＇s mechanic energy so as to maintain the robot＇s passivity. In this research, we furture take into account of the robot＇s dynamical model uncertainties and propose a robust passive impedance control. Computer simulations of a 2-link manipulator interacting with a dynamic wall show the effectiveness of our robust control approach.

On Observer-based Passive Robust Impedance Control of a Robot Manipulator

This paper studies the passive impedance control of a robot manipulator with model uncertainty to perform manipulation tasks while interacting with dynamic environment. Impedance control is a powerful approach for the robot to perform mechanical tasks while interacting with dynamic environment. However, in our previous research, it was clarified that, the time varying impedance center as well as the robot＇s model uncertainty influences the robot＇s passivity, which may lead to serious safety problem for both the robot as well as its environment. In order for the robot to keep its passivity as well as to realize desired objective impedance, in this paper, a novel observer based control design is proposed. Computer simulations of a 2-1ink manipulator interacting with a dynamic wall show the effectiveness of our control approach.

Passive Velocity Field Control of a Redundant Cable-Driven Robot with Tension Limitations

This paper proposes a novel dynamic control approach for a cable-driven robot with high redundant actuation and cable tension limitations to perform tracking task while interacting with environment. In order for a cable-driven exoskeleton robot to execute the task smoothly and safely, it is necessary to consider the tracking motion performance as well as passivity when interacting with the environment under the conditions of the actuation cables＇ redundancy and the pulling limitation. With the additional consideration of the maximum limitation of the cable tension, cable-driven robot actually can only apply a certain range of feasible wrench on the external environment, which makes the task executed by robot be restricted. In order to make designed wrench be feasible and keep the desired trajectory tracking ability, we present a new control method by extending PVFC （passive velocity field control） method considering tracking stability and passivity. The approach augmented a higher dimensional virtual flywheel dynamics in a specific orthogonal complement space of the cable＇s actuation space. After the final adjustment of the designed wrench with respect to the cable＇s constraint, this method is capable of driving the cable robot to complete the trajectory tracking task and realize the passivity.

Estimation of an Object＇s Physical Parameter by Force Sensors of a Dual-arm Robot

We are developing a nursing-care robot for physical care tasks. The concept of this robot is to promote the cared persons by the robot to activate their own motion ability as long as possible. This may lead to the improvement of the cared person＇s movement volition and movement abilities. In order to realize safe and human friendly robot care tasks, full body manipulation is an important technology, for which it is necessary to estimate the subject＇s center of gravity from the contact positions and forces with the robot＇s two arms. In this paper, we estimate the center of gravity of object based on the contact point and the contact force estimated by force sensor on both robot arms. The position of gravity center is important to realize care tasks stably. We performed experiments and simulations for the single point contact and dual points contact cases using a cylindrical object. As a result, it is found that although some errors were recognized in the experiments compared with the simulations, the relations between the contact positions and such errors were observed. Such experimental error mainly comes from the difference of shape between the real robot and the model of the robot in simulation.

基于块相关框架的多参考微扰理论和多参考耦合簇理论

传统单参考电子相关方法已经发展成熟,但很多时候无法正确描述共价键解离、双(多)自由基和激发态等电子之间相关性非常强的体系。近年来发展的多参考微扰理论和多参考耦合簇理论以多个行列式的线性组合为参考波函数,采用不同的方式有效考虑电子之间的动态相关,对强关联体系的描述取得了显著的改进。但根据理论出发点和精度要求的不同发展出了许多多参考理论,仍无一个公认的、令人满意的方案。本文将结合与常见电子相关方法在理论框架和计算精度上的比较,详细阐述块相关理论的基本原理,并介绍基于块相关的"另类"多参考电子相关方法。最后本文还简单展望了多参考电子相关方法今后的发展趋势。

Reflection-type holographic disk-type memory using three-dimensional speckle-shift multiplexing

This review presents a reflection-type holographic memory using three-dimensional(3D)speckle-shift multiplexing. First, the schematic of the proposed memory system was described. Then,experimental demonstrations of multiplexing in plane and along the depth direction were presented. The estimated storage capacity of single layer recording was introduced and the maximum storage capacity was discussed. To increase the storage capacity, the multi-layered recording was described. In the multilayered recording, the storage capacity can be increased by appropriate arrangement of holograms in each layer.

IMPLEMENTATION OF 3-VALUED PARACONSISTENT LOGIC PROGRAMMING TOWARDS DECISION MAKING SYSTEM OF AGENTS

Due to the rapid development of applications of artificial intelligence and robotics in recent years, the necessity of reasoning and decision making with uncertain and inaccurate information is increasing. Since robots in the real world are always exposed to behavioral inaccuracies and uncertainty arising from recognition methods, they may occasionally encounter contradictory facts during reasoning on action decision. Paraconsistent logic programming is promising to make appropriate action decisions even when an agent is exposed to such uncertain information or contradictory facts, but there has been no implementation of this programming to the best of our knowledge. We propose a resolution algorithm for the 3-valued paraconsistent logic programming system QMPT0 and its implementation on SWI-Prolog. We also describe an application of the 3-valued paraconsistent logic programming regarding agent decision making.

Brain Response to Aversive Taste for Investigating Taste Preference

To clarify the intrinsic food preference mechanism, we investigated brain neurophysiological responses to unpleasant gustatory stimuli using electroencephalogram (EEG) and near-infrared hemoencepalogram (NIR-HEG) simultaneously. A conventional delayed response task based on Go/Nogo paradigm was adopted to extract real brain response components from spontaneous background signals. We found excessive evoked EEG potential responses to both bitter and sour stimuli, while we didn’t find excessive changes in purified water condition. These potentials appeared before P3, hence, they potentially predicted unconscious attention to the gustatory stimuli. We also identified a late contingent negative variation (CNV) and corresponding P3 for sour stimulus. In addition, NIR-HEG responses showed relative changes for every stimulus and we considered that these NIR-HEG signal changes were attributed to the prefrontal cortex activity for regulating negative emotional valence against aversive tastes typically including sour and bitter. In spite of limitation to timing accuracy of taste presentations, the early markers found in this study could be fundamentals for investigating individual food preference.

An fNIRS Research on Prefrontal Cortex Activity Response to Pleasant Taste

Functional Near-Infrared Spectroscopy (fNIRS), as a non-invasive neuroimaging technique, was used to monitor the activation of prefrontal lobe on human brain during sweet taste processing. The primary aim of the present study was to find the region of interest (ROI) which is related to sweetness, and make further understanding of the central organization of taste. Based on event-related design, the experiments were performed with 16 volunteers by sweet taste stimulus. It was confirmed that the prefrontal cortex (PFC) is involved in sweet taste processing and fNIRS provided an alternative way for studying taste-related brain function under more natural conditions. This study might be effective for detecting the accession area in the cortex of sweet taste and helpful for studying on human feeding and taste disease like taste dyspepsia or disorder.

On Human Autonomic Nervous Activity Related to Behavior, Daily and Regional Changes Based on Big Data Measurement via Smartphone

This research uses a large amount of autonomic nervous system data (approximately 100,000 entries) to investigate the relationship between human autonomic nervous activity and behaviors, daily and regional changes. Data were measured via a heart rate variability analysis system that utilizes the camera of smartphones. This system was developed by the authors during previous research. The relations between autonomic nervous system and behaviors, total power and sympathetic nervous activity were found to rise after waking, while during leisure time, the total power rises and sympathetic nervous activity is inhibited. Concerning the relationship between autonomic nervous system and day of the week, it was found that total power decreases from the middle through the latter part of the week (namely, Wednesday, Thursday, and Friday), while it rises on Saturday, while the sympathetic nervous activity is suppressed on Saturday. Regarding the relationship between autonomic nervous system and region, it was found that total power is lower in the Kanto region of Japan than in others. This study also shows statistical proof (using a large amount of measurement data) to ideas held by the public for years. Thus, the data can be considered meaningful to the society, and the authors hope that it helps to improve work-life balance.

On Human Autonomic Nervous Activity Related to Weather Conditions Based on Big Data Measurement via Smartphone

This research uses our previously-developed smartphone camera-based heart rate change analysis system to survey the correlation between weather patterns and the autonomic nervous activity across a big data set of approximately 200,000 entries. The results showed a trend in which a significant decrease was seen in sympathetic nervous activity in both males and females—the higher the temperature. In addition, a significant increase was seen in the sympathetic nervous system in both males and females—the higher the atmospheric pressure. Lastly, a significant decrease was seen in the sympathetic nervous system in both males and females—the more precipitation there was. These results accord with prior research and with human biological phenomena, and we were able to use a data set of approximately 200,000 entries to statistically demonstrate our hypothesis. We believe this represents a valuable set of reference data for use in the health care.

An fNIRS-Based Study on Prefrontal Cortex Activity during a Virtual Shopping Test with Different Task Difficulties in Brain-Damaged Patients

We developed a Virtual Shopping Test with three different task levels for assessment of daily cognitive function using virtual reality technology. The objective of present study was to investigate the difference on task performance, brain activation and subjective assessment in relation to the difficulty levels of the tasks. Subjects were asked to buy specific 2 items in Task 1, 4 items in Task 2, and 6 items in Task 3 at a virtual mall. The tasks and questionnaires were conducted on 10 convalescent brain-damaged patients and 6 healthy young adults. Hemodynamic changes in the prefrontal cortex (PFC) during activation due to the tasks were examined using functional near-infrared spectroscopy. As the result, the mean total time was significantly longer for the patients than for healthy subjects. PFC showed a greater response for related Task 2 than Task 1 in shopping and moving phase in patient group. The patients evaluated Tasks 1 and 2 are more difficult and bring more psychological load than healthy adults subjectively. That is, although the healthy adults did not show large difference in their task performances as well as PFC responses, they can evaluate the differences between three task levels, subjectively, while which could not be for the patients means that patients could not distinguish the difference of the tasks, subjectively. The results suggest that 4-item shopping task might be enough difficulty level that causes brain activation for the brain-damaged patients.

Mixed Music Analysis with Extended Specmurt

This paper introduces a mixed music analysis method using extended specmurt analysis. Conventional specmurt can only analyze a multi-pitch music signal from a single instrument and cannot analyze a mixed music signal that has several different types of instruments being played at the same time. To analyze a mixed music signal, extended specmurt is proposed. We regard the observed spectrum extracted from the mixed music as the summation of the observed spectra corresponding to each instrument. The mixed music has as many unknown fundamental frequency distributions as the number of instruments since the observed spectrum of a single instrument can be expressed as a convolution of the common harmonic structure and the fundamental frequency distribution. The relation among the observed spectrum, the common harmonic structure and the fundamental frequency distribution is transformed into a matrix representation in order to obtain the unknown fundamental frequency distributions. The equation is called extended specmurt, and the matrix of unknown components can be obtained by using a pseudo inverse matrix. The experimental result shows the effectiveness of the proposed method.