Auditory information processing is very important in the darkness where vision information is extremely limited. Barn owls have excellent hearing information processing function. Barn owls can detect a sound source in the high accuracy of less than two degrees in both of the vertical and horizontal directions. When they perform the sound source localization, the barn owls use the interaural time difference for localization in the horizontal plane, and the interaural level difference for localization in the vertical plane. We are constructing the two-dimensional sound source localization model using pulse-type hardware neuron models based on sound source localization mechanism of barn owl for the purpose of the engineering application.
In this paper, we propose a pulse-type hardware model for level difference detection based on sound source localization mechanism of barn owl. Firstly, we discuss the response characteristics of the mathematical model for level difference detection. Next we discuss the response characteristics of the hardware mode. As a result, we show clearly that this proposal model can be used as a sound source localization model of vertical direction.

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In this paper, we propose a new design method for linear phase FIR (Finite Impulse Response) filters with discrete coefficients. In a hardware implementation, filter coefficients must be represented as discrete values. The design problem of digital filters with discrete coefficients is formulated as the integer programming problem. Then, an enormous amount of computational time is required to solve the problem in a strict solver. Recently, ACO (Ant Colony Optimization) which is one heuristic approach, is used widely for solving combinational problem like the traveling salesman problem. In our method, we formulate the design problem as the 0-1 integer programming problem and solve it by using the ACO. Several design examples are shown to present effectiveness of the proposed method.

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Regenerative medicine is a promising therapy for injuries and diseases of the central nervous system (CNS). Implantation of stem cell-derived neurons into the recipient tissue is one of the key processes of the therapy. How the implanted cells establish functional connections with the intact neurons, and whether the established connections are maintained stably for a long time, remain unknown. Here, we report a novel co-culture device for visualizing interconnections between primary and differentiated neuronal cultures, and long-term monitoring of neuronal activity. A circular micro-chamber surrounded by another chamber is aligned on a microelectrode array (MEA). These chambers are interconnected through 36 micro-tunnels. Stem cell-derived neurons were cultured in the inner circular chamber, and primary neurons taken from mouse cortices were cultured in the surrounding chamber. Neurites outgrew into the micro-tunnels from both primary and differentiated neurons. The immunofluorescence images indicate that synaptic connections are formed between them. Propagation of electrical activity was observed 6 days after starting co-culture. More than half of the spontaneous activity was initiated from primary neurons, and probability of activity propagation to the stem cell-derived neurons gradually increased with culture days. These results suggest that our device is feasible for long-term monitoring of interaction between stem cell-derived cells and the recipient tissue.

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Perceptual integration and segregation of alternating tone sequence differing in frequency (ABA-ABA-…) depend on the frequency differences (ΔFs) between A and B tones and the inter-tone intervals (ITIs) between successive tones. In the auditory cortex, tonotopic separation, forward suppression and multisecond habituation have been considered as possible neural mechanisms of this perceptual phenomenon. These mechanisms, however, cannot completely account for the van Noorden's perceptual boundary and the temporally continuous perception of auditory streaming. Here we examined the temporal changes of the functional network properties in the auditory cortex in response to tone sequences with different ΔFs and ITIs. Specifically, we recorded local field potentials using microelectrode arrays from anesthetized rats and constructed the functional network based on phase synchrony in gamma-band oscillation. Consequently, the networks consisted of sub-networks highly correlated with the place code of frequency, i.e., tonotopic map, and the sub-network selective to B tones lasted for a prolonged period at large ΔF. Such characteristic substructures of functional network are a possible candidate of neural basis of auditory stream segregation.

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The multilateration is an aircraft surveillance system for airport surface movement utilizing hyperbolic positioning. The system performances are sometimes degraded by multipath signals in an airport apron area. ENRI has proposed an enhanced multilateration system named as OCTPASS (Optically Connected Passive Surveillance System), that has an interference immunity in multipath environment. This paper describes evaluation results for OCTPASS prototype equipments.

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This paper presents the locomotion control of micro electro mechanical systems (MEMS) micro robot. MEMS micro robot demonstrates the locomotion control by the pulse-type hardware neural networks (P-HNN). P-HNN generates oscillatory patterns of electrical activity such as living organisms. The basic component of P-HNN is pulse-type hardware neuron model (P-HNM). P-HNM has same basic features of biological neurons such as threshold, refractory period, spatio-temporal summation characteristics and enables the generation of continuous action potentials. P-HNN was constructed by MOSFETs, can be integrated by CMOS technology. Same as the living organisms P-HNN realized the robot control without using software programs, or A/D converters. The size of micro robot fabricated by the MEMS technology was 4×4×3.5 [mm]. The frame of robot was made of silicon wafer, equipped with rotary type actuators, link mechanisms and 6 legs. MEMS micro robot emulated the locomotion method and the neural networks of the insect by rotary actuators, link mechanisms and P-HNN. As a result, we show that P-HNN can control the forward and backward locomotion of fabricated MEMS micro robot, and also switched the direction by inputting the external trigger pulse. The locomotion speed was 19.5 [mm/min] and the step width was 1.3 [mm].

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Development of downsized digital cameras causes a lot of undesirable shaking blurred images. In order to restore these images, we need to estimate PSF (Point Spread Function) from them. It has been proposed to estimate PSF using cepstrum images. There are PSF features in the cepstrum images of blurred images. We can estimate PSF by searching pixels in the cepstrum images. However cepstrum images also show features of ground-truth images, so we can't estimate the PSF accurately. We propose estimation method of PSF by using GA. We adopt the cepstrum images as a fitness function, thus the estimation results aren't affected by other features in cepstrum images. We have just confirmed the effectiveness of our proposed method by using some simulations.

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The total number of deaths by traffic accidents was 4,863 in 2010 and the percentage of pedestrians in the deaths tended to increase in Japan. In recent years, to provide measures for accident avoidance has been urgently required for the people on the roads or streets including pedestrians and cyclists, so called “vulnerable road users”. In the present study, technologies to detect pedestrians by forward images with cameras installed in vehicles are under development. The purpose in this study is to improve the technologies to detect and track pedestrians with a high degree of accuracy of images with a single camera. In this study, the authors predicted pedestrians' activities by monitoring pedestrians for a given length of time and developed an algorithm to recognize pedestrians and to track the pedestrian movements with a higher degree of accuracy. The effectiveness of the algorithm was investigated by pedestrians' images on real-world roads. Regarding detecting the pedestrian feature descriptor, the authors newly found that an ECoHOG accumulating the integration of gradient intensities was the best method to decrease both the undetectable and excessive detectable ratio. Therefore, the usage of the new method by images captured on the real road was validated.

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In this paper, we consider a multi-objective optimization method in order to obtain a preferred solution for the buffer material optimal design problem in the high-level radioactive wastes geological disposal. The buffer material optimal design problem is formulated as a constrained multi-objective optimization problem. Its Pareto optimal solutions are distributed evenly on whole bounds of the feasible region. Hence, we develop a search method to find a preferred solution easily for a decision maker from the Pareto optimal solutions which are distributed evenly and vastly. In the preferred solution search method, the visualization technique of a Pareto optimal solution set using the self-organizing map is introduced into the satisficing trade-off method which is the interactive method to obtain a Pareto optimal solution that satisfies a decision maker. We confirm the effectiveness of the preferred solution search method in the buffer material optimal design problem.

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In this paper, we present a new type of hybrid methods for global optimization with Particle Swarm Optimization (PSO) and Differential Evolution (DE), which have attracted interests as heuristic and global optimization methods recently. Concretely, “p-best solutions” as the targets of PSO's particles are actuated by DE's evolutional mechanism in order to promote PSO's global searching ability. The presented hybrid method works effectively because PSO acts as a local optimizer and DE plays a role as a global optimizer. To evaluate performance of the hybridization, our method is applied to some benchmarks and is compared with the separated PSO and DE. Through computer simulations, it is certified that the proposed hybrid method performs fairy better than their separated algorithm.

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In this paper, as one of global optimization methods for 0-1 combinatorial optimization problems with constraints, a continuous relaxation approach is presented, in which the continuous variables are transformed into binary variables through a sorting procedure of continuous variables taking the constraints into consideration. The new type of relaxation approach enables us to apply Particle Swarm Optimization, which is effective heuristic method for global optimization with continuous variables. Here, our presented approach is interpreted as one of evolutional computing methods because the transformation of continuous variables into binary ones corresponds to transform genotype into phenotype, which is reverse to a relation in usual evolutional computing.

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The effect of an outage caused by a disaster is serious to the society, because the power distribution line is a common basic infrastructure for life support. And the time estimation of emergency restoration process of power distribution line after a disaster is an emerging problem for the safety and security of the society. But the time estimation is a difficult problem and the only practical method in use is a simple approximation method, which doesn't take account of geographical characteristics of the objective area. So, we developed a method which can take account of the influences caused by the geographical characteristics of the objective area on the estimation of the emergency restoration. In this article, we describe an experimental analysis by the method.

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In software development process of embedded real-time systems, the design of the task cooperation process is very important. The cooperating process of such tasks is specified by task cooperation patterns. Adoption of unsuitable task cooperation patterns has fatal influence on system performance, quality, and extendibility. In order to prevent repetitive work caused by the shortage of task cooperation performance, it is necessary to verify task cooperation patterns in an early software development stage. However, it is very difficult to verify task cooperation patterns in an early software developing stage where task program codes are not completed yet. Therefore, we propose a verification method using task skeleton program codes and a real-time kernel that has a function of recording all events during software execution such as system calls issued by task program codes, external interrupts, and timer interrupt. In order to evaluate the proposed verification method, we applied it to the software development process of a mechatronics control system.

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This paper presents an assist control method for flexible parts conveyance task using power assist type conveyance system. The assist control method should be designed so as to not only suppress the vibration but also reduce degradation of operating feel. For this purpose, multiple impulse shaped signals are used as feedforward signals in order to reduce the vibration of flexible parts during conveyance.
In addition, adjustment time is introduced to adjust input timing of impulse shaped signal and to suppress vibration. Moreover, in order to improve the degradation of operating feel, the smaller amplitudes of the three impulse shaped signals are used and input repeatedly. The effectiveness of the proposed system was verified experimentally.

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In this paper, the modeling error between a real system to be controlled and its T-S fuzzy model is considered, and fuzzy estimator is employed to cope with the error. As a result, it reaches an adaptive controller that has two parts: one is obtained by solving certain linear matrix inequalities (LMIs) (fixed part) and another one is acquired by the fuzzy estimator in which the related parameters are tuned by adaptive law (variable part). The proposed controller can guarantee the closed-loop system to be uniformly asymptotically stable. Also, simulation results are provided to illustrate that the proposed controller is more effective to deal with a system than the regular controller when using the T-S fuzzy model.

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In control theory, SMC is a nonlinear control method. The main strength of SMC is its robustness SMC can be used in the design of state observer. Therefore, the design method of the VSS observer that has robustness is proposed. The actual control is addition of the equivalent control and the nonlinear control. Nonlinear control is applied for control of state errors. Furthermore, a system becomes stable by applying the nonlinear control. We derive new nonlinear control. The control uses a composition of the discrete time slide mode observer and the error presumption observer. Thereby, an applicable condition can be eased.

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In order to discretize continuous dynamics with variable structures, Euler integrators are often used. However, Euler integrators include large discretization errors, so that they deteriorate performances of the discretized dynamics. Use of Richardson extrapolation (RE) and fractional delay (FD) can reduce the discretization errors. However, Euler integrators using RE and FD directly have infinite gains at their Nyquist frequencies, and they are unsuitable for integrations of the dynamics with variable structures. In this paper, we propose an improved integrator which is suitable for integrations of the dynamics with variable structures. The proposed method consists of a high forward gain and a feedback structure with a high-precision differentiator. To realize the high-precision differentiator, RE and a high sampling rate (HSR) instead of FD are used, and those are implemented by FPGA. Its effectiveness is verified by software simulations, hardware in the loop (HIL) simulations, and experiments.

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In recent years, various networks have come to exist in our surroundings. Not only the internet and airline routes can be thought of as networks: protein interactions are also networks. An “economic network design problem” can be discussed by assuming that a vertex is an economic player and that a link represents some connection between economic players. In this paper, the Airlines network is taken up as an example of an “economic network design problem”, and the Airlines network which the profit of the entire Airlines industry is maximized is clarified. The Airlines network is modeled based on connections models proposed by Jackson and Wolinsky, and the utility function of the network is defined. In addition, the optimization simulation using the evolutionary computation is shown for a domestic airline in Japan.

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In order to observing a waveform of a high symbol-rate optical signal, all optical signal sampling technique using a periodically poled LiNbO₃ (PPLN) wavelength converter is experimentally investigated. An optical gate is realized by a chirped PPLN having 2.2-nm QPM wavelength range where caused difference frequency generation between a high symbol rate optical signal and short pulses for sampling. An experiment of optical signal sampling is carried out by injecting an optical pulse train with 2.8-ps time width and an 160 Gb/s signal to the PPLN thus basic operation of the proposed scheme is confirmed.

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A transcutaneous optical information transmission system (TOITS) offers the most promising method for noninvasively transmitting the information to control a total artificial heart (TAH). We had used light-emitting diode (LED) and photo diode (PD) with different wavelengths for full-duplex bidirectional communication in the TOITS. In this study, reduction of optical crosstalk in full-duplex bidirectional communication was investigated by using a combination of two orthogonal polarizers with the same wavelength. As a result, we confirmed that optical crosstalk could be prevented for communication through a cow's skin (3.5 mm thick) and that the signal waveform could be transmitted satisfactorily.

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A culture device requiring no medium replacement for a long time was developed to study pharmacological and electrophysiological effects on cultured cardiomyocytes. The survival rate of the cultured cardiomyocytes in the device was higher than that in a normal culture dish for the culture duration of one to two weeks. The result suggests that this culture device using molecular diffusion can be utilized for long-term culture of cardiomyocytes without any pumps.

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In our development of a new monitoring system for human utterance, we investigated temporal variation when a participant verbalized five Japanese vowels by using an acceleration sensor attached to the lower teeth. We then analyzed the variation by wavelet transform and obtained the temporal spectral density. We were able to observe the frequencies corresponding to voice sound and the lower jaw movements. The results indicated that the possibility of speech recognition with not only voice sounds but also lower jaw movements by our system.

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We aim to develop the method that automatically detects the cracks from the images that were taken from the concrete inner surface in tunnels, etc. Assuming that the images are taken from the mobile mapping systems, we have considered the method utilizing the crack's projection model on the projection plane of moving cameras. By the prototype, we tried to process the 2mm/pixel images in order to detect the 0.3mm-wide cracks, which have registered as the real crack by the human inspectors. As the result, most of the cracks were detected.

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