In this paper, the transducer that is suitable for the ultrasonic wireless power transmission system is discussed. The transducer is designed based on the Mason's equivalent circuit theory, basically. Design parameters of the transducer are optimized for by using the multi physics analysis and developed. As results, it is confirmed that the transmission efficiency is drastically improved to more than 50%. This result suggests that the WPT by acoustic wave is practicable.
A battery-less wireless sensor node using a vibration-driven MEMS electret energy harvester has been prototyped. With hybrid high-aspect ratio parylene springs and high-performance electret material based on perfluoro polymer CYTOP, more than 3μW output power can be obtained in a broad range vibration frequency of 26-40 Hz at 1.4 G. By integrating the energy harvester with a power management circuit, low-power-consumption CPU, and RF IC, intermittent wireless transmission with an interval of 80.6 s has been realized.
The wireless power transmission via sheet medium is a novel physical form of communication that utilizes the surface as a medium to provide both data and power transmission services. To efficiently transmit a relatively-large amount of electric power (several watts), we have developed a wireless power transmission system via sheet medium that concentrates the electric power on a specific spot by using phase control of multiple inputs. However, to find the optimal phases of the multiple inputs making the microwave converge on a specific spot in the sheet medium, the prior knowledge of the device's position, and the pre-experiment measuring the output power, are needed. In wireless communication area, it is known that the retrodirective array scheme can efficiently transmit the power in a self-phasing manner, which uses the pilot signals sent by the client devices. In this paper, we apply the retrodirective array scheme to the wireless power transmission system via sheet medium, and propose a power transmission scheme using the phase-adjustment of multiple inputs. To confirm the effectiveness of the proposal scheme, we evaluate its performance by computer simulation and realistic measurement. Both results show that the proposal scheme can achieve the retrodirectivity over the wireless power transmission via sheet medium.
Recently, micro vibration energy harvesters are attracting much attention for wireless sensor applications. To answer the power requirement of practical applications, the design methodology is important. This paper first reviews the fundamental theory of vibration energy harvesting, and then discusses how to design a micro vibration energy harvester at a concept level. For the micro vibration energy harvesters, independent design parameters at the top level are only the mass and stroke of a seismic mass and quality factor, while the frequency and acceleration of vibration input are given parameters determined by the application. The key design point is simply to make the mass and stroke of the seismic mass as large as possible within the available device size. Some case studies based on the theory are also presented. This paper provides a guideline for the development of the micro vibration energy harvesters.
Recently, semiconductor counterfeiting has become an increasingly serious problem. Therefore, techniques to prevent the counterfeit by using random characteristic patterns that are difficult to control artificially have attracted attention. The physical unclonable function (PUF) is one of the techniques. It is a method to derive ID information peculiar to a device by detecting random physical features that cannot be controlled during the device's manufacture. Because information such as the ID information is difficult to replicate, PUF is used as a technique to prevent counterfeiting. Several studies have been reported on PUF. Arbiter PUF, which utilizes the difference in signal propagation delay between selectors, is the typical method of composing PUF using delay characteristics. This paper proposed a new PUF which is based on the arbiter PUF. The proposed PUF introduces new multiplexing selector units. It attempts to generate an effective response using the orders of three signal arrivals. Experiments using FPGAs verify the validity of the proposed PUF. Although Uniqueness is deteriorated, Correctness, Steadiness, Randomness and Resistance against the machine learning attacks are improved in comparison with conventional one.
During the forearm exercise, it is generally understood that the inner muscles work for the task, and the outer muscles work to fix the joints for the efficient work of the inner muscles. For evaluation of the exercise, quantitative measurement of inner muscle activities is necessary. Electromyograph (EMG) and oxygen monitoring using continuous-wave near-infrared spectroscopy (CW-NIRS) have been used for the evaluation because both of them are the modalities of safe, portable and noninvasive measurements of muscle activities. However, these modalities can show the qualitative changes in the muscle activities in the vicinity of the skin surface. Time-resolved diffuse optical tomography (TR-DOT) can quantitatively provide tomographic images of the changes in the oxygenation state of the whole muscles. In vivo experiments of TR-DOT were performed for human forearms under handgrip exercises, and DOT images of the changes in the oxygenation state of the forearms were reconstructed using the algorithm based on the modified generalized pulsed spectrum technique. The DOT images are compared with the MR-images, and it is shown that the activities of the inner muscles of the forearms were active during the handgrip excises.
We have developed a rehabilitation tool used for treatment of patients suffering from hemiplegia and evaluation of the paralysis-stage. The tool consists of a PC and button switches for a computer game so that it is not expensive, available in anywhere, and possible to get a change of air in the patients. In this study, we have evaluated behavior indices such as an operation time to play with the games both in healthy young students and patients with paralysis. From experimental results, it was shown that the recorded behavioral indices showed the strong dependence on the motion control function of a subject. Preceding evaluation of effectiveness in rehabilitation of the developed tool, possible application of the tool in evaluation of the motion control function of the patients with hemiplegia was discussed in this paper.
The three dimensional measurement & modeling system with digital cameras on PC is now making progress and its need and hope is increasingly felt in terrestrial (close-range) photogrammetry for such sectors as cultural heritage preservation, architecture, civil engineering, manufacturing, measurement etc. Therefore, we have developed a system to improve the accuracy of stereo-matching, which is the very core of 3D measurement. As for stereo-matching method, in order to minimize the mismatching and to be robust in geometric distortions, occlusion, as well as brightness change, we invented Coarse-to-Fine Strategy Method by integrating OCM (Orientation Code Matching) with LSM (Least Squares Matching). Thus this system could attain the accuracy of 0.26mm, when we experimented on a mannequin. And when we actually experimented on the archeological ruins in Greece and Turkey, the accuracy was within the range of 1cm, compared with their blue-print plan. Besides, formally workers used to take at least 1.5 month for this kind of survey operation with the existing method, but now workers need only 3 or 4 days. Thus, its practicality and efficiency was confirmed. This paper demonstrates our new system of 3D measurement and stereo-matching with some concrete examples as its practical application.
In this paper, a robust current control system for a synchronous reluctance electrical motor by an ILQ (Inverse Linear Quadratic) design method is proposed newly. First, for performing simultaneously decouple and large region linearization of an d-q axes system in the synchronous reluctance electrical motor using nonlinear state feedback, it is derived that a linear current-voltage state equation linearized model by the d-q axes decouple of the synchronous reluctance electrical motor. Next, according to the ILQ design method, an optimum solution and an optimal condition that achieve the robust current control system for the synchronous reluctance electrical motor are analytically derived, then the robust current control system can be designed. Finally, in practical experiments, we compare the proposed method with the PI (Proportional Integral) control method, the creativity and the usefulness of the proposed method are confirmed by experimental results.
We describe a simulation model based on an avian ecosystem for determining what causes birdsong evolution. It is already known that songbirds communicate with a “birdsong.” This birdsong is used in territorial and courtship behaviors. Some previous researches have suggested that songs related to territorial behaviors should have simple structures while those related to courtship behaviors should have complex ones. We suspect that birdsongs are constantly evolving to achieve a suitable balance between the two behaviors while considering the surrounding environment. We consider avian habitat density to be one of the most important environmental factors influencing birdsong evolution and therefore created different densities in a simulation model. In this paper, we propose a birdsong acquisition model by sexual selection that contains both territorial and courtship behaviors. We conducted simulations with the proposed model and determined that the evolution of birdsongs differs depending on a bird's habitat density. The experimental results suggest that a bird's habitat density influences the structure of birdsongs, as well.
Robot arm control and having meal aid system with eye based HCI is proposed. The proposed system allows disabled person to select desirable food from the meal tray by their eyes only. Robot arm which is used for retrieving the desirable food is controlled by human eye. At the tip of the robot arm, tiny camera is equipped. Disabled person wear a glass of which a single Head Mount Display: HMD and tiny camera is mounted so that disabled person can take a look at the desired food and retrieve it by looking at the food displayed onto HMD. Experimental results show that disabled person can retrieve the desired food successfully. It also is confirmed that robot arm control by eye based HCI is much faster than that by hands.
This paper proposes a new and more reliable method for template matching that is using the first derivation edge-direction. A template image is separated into local block areas and sum of inferior angle between edge-directions of target image and edge-directions of template image are calculated in all block areas. For each block, a coordinate that is the highest similarity of edge-directions gets a vote and a target coordinate is decided by its result. The experimental results show that the proposed method was robust to the debased target image with the conventional methods.
Constructing processes of image transformation manually requires a lot of effort, so several methods to automate it with machine learning, such as neural networks or genetic programming, have been proposed. Most of them are just constructed image filters that calculate an output value from values in local area in each pixel independently. However in several tasks, like area detections, the information of more distant area is helpful to processing. In this paper, we introduce a new neural network model for automatic construction of image transformation. The proposed model is composed of a regular array of the identical evolutionary neural networks, represented Real Valued Flexibly Connected Neural Network (RFCN) we previously proposed, and each RFCN connects with neighbor RFCNs. The proposed model is represented Cellular RFCN (CRFCN). Because of the local connections, each RFCN can consider information of distant area indirectly. We apply CRFCN to three kinds of image transformation tasks comparing with other methods and examine the effectiveness.
In this paper, a stock trading model is proposed using a graph-based evolutionary algorithm named Genetic Network Programming-Sarsa (GNP-Sarsa) with multi-subroutines. The method is developed for discovering the frequent transitions of GNP, which can be seen as the repetitive subgraphs, i.e., building blocks with useful knowledge over the entire graph structure, and modularizing them as subroutines. The important points of the subroutines mechanism are as follows: First, the nodes and node connections discovered in the subroutines are reused to create effective trading rules. Second, the evolution can be achieved so quickly by narrowing the search space with subroutines. Last, as the kinds of subroutines increase, the generalization ability is improved since more generalized frequent transitions of GNP, i.e., building blocks are found instead of precisely modeling the training data, which leads to the overiftting problem. The following two experiments are discussed: 1) varying the number of subroutine nodes in the main GNP and 2) varying the kinds of subroutines to be generated. Simulation results on the stock markets show that the proposed method can generate more efficient and generalized trading models and obtain much higher profits.
In this paper, Rationally oriented Forgettable Profit Sharing method (RFPS) for reinforcement learning is proposed. Although the Profit Sharing (PS) provides good performances in real environments, its learning is often slow in long term tasks because it is difficult to determine the adequate discount rate which satisfies the Miyazaki rational theorem. There are several rationality-relaxed PS methods which work well for such tasks. However, these PS may result in many irrational loops. The proposed method fulfills the rationality by forgetting the reinforced irrational loops. This method can be easily combined with ordinary PS methods and performs well in long term tasks. The simulation results show that the proposed method can learn more efficiently than the conventional PS methods.
This paper proposed a new technique which makes the strategy trees for the derivative (option) trading investment decision based on the behavioral finance theory and optimizes it using evolutionary computation, in order to achieve high profitability. The strategy tree uses a technical analysis based on a statistical, experienced technique for the investment decision. The trading model is represented by various technical indexes, and the strategy tree is optimized by the genetic programming(GP) which is one of the evolutionary computations. Moreover, this paper proposed a method using the prospect theory based on the behavioral finance theory to set psychological bias for profit and deficit and attempted to select the appropriate strike price of option for the higher investment efficiency. As a result, this technique produced a good result and found the effectiveness of this trading model by the optimized dealings strategy.
In a smartphone market, smartphone makers encourage smartphone application providers (AP) to create more popular smartphone applications through making a revenue-sharing contract with AP and providing application-purchasing support to end users. In this paper, we study revenue-sharing and application-purchasing support problem between a risk-averse smartphone maker and a smartphone application provider. The problem is formulated as the smartphone makers's risk-sensitive stochastic control problem. The sufficient conditions for the existence of the optimal revenue-sharing strategy, the optimal application-purchasing support strategy and the incentive compatible effort recommended to AP are obtained. The effects of the smartphone makers's risk-sensitivity on the optimal strategies are also discussed. A numerical example is solved to show the computation aspects of the problem.
We developed the system that knowledge could be discovered and shared cooperatively in the organization based on the SECI model of knowledge management. This system realized three processes by the following method. (1)A video that expressed skill is segmented into a number of scenes according to its contents. Tacit knowledge is shared in each scene. (2)Tacit knowledge is extracted by bulletin board linked to each scene. (3)Knowledge is acquired by repeatedly viewing the video scene with the comment that shows the technical content to be practiced. We conducted experiments that the system was used by nurses working for general hospitals. Experimental results show that the nursing practical knack is able to be collected by utilizing bulletin board linked to video scene. Results of this study confirmed the possibility of expressing the tacit knowledge of nurses' empirical nursing skills sensitively with a clue of video images.
The astable multivibrator of the integral type operation using 2 CMOS-XOR/XNOR gates doesn't oscillate only by the power supply's being turned on. On the other hand, the proposed astable multivibrator of the integral type operation by 3CMOS-XOR/XNOR gates oscillates surely when the power supply is turned on.