This paper describes a method for measuring magnetic permeability dispersion of ferrite cores widely used in RF devices such as splitters in CATV systems. The present method has a step of measuring reflection coefficients for three kinds of microstrip line circuits, one having a test sample (ferrite core) mounted on it, one with a non-magnetic core instead of the ferrite, and one with an impedance matching resistor only. From the three reflection coefficients derived, the impedances of the coils with the ferrite and non-magnetic cores, respectively, are calculated and the complex permeability is determined by dividing the impedance of the ferrite core coil by the reactance component of the non-magnetic core coil. In this paper, the accuracy of the proposed method is discussed through a electromagnetic simulation and then the calculated results are compared with the experiments, indicating the validity of the method.
The wavelength red-shifting of integrated DFB (Distributed feedback) laser and EA (Electro-absorption) modulator with applied modulator bias voltage has been investigated and this phenomenon is estimated to be due to non-uniform temperature distribution in the device and caused by thermal crosstalk. From the experimental data and thermal analysis, increased absorbed photocurrents associated with EA modulator bias and dissipated power in the EA modulator lead to the temperature increase in continuously operating DFB laser, resulting wavelength red-shifting.
X-ray diagnosis depends on the intensity of transmitted and scattered waves in X-ray propagation in biomedical media. X-ray is scattered and absorbed by tissues, such as fat, bone and internal organs. However, image processing for medical diagnosis, based on the scattering and absorption characteristics of these tissues in X-ray spectrum is not so much studied. To obtain precise information of tissues in a living body, the accurate characteristics of scattering and absorption are required. In this paper, X-ray scattering and absorption in biomedical media are studied using 2-dimensional FDTD method. In FDTD method, the size of analysis space is very limited by the performance of available computers. To overcome this limitation, parallel and successive FDTD method is introduced. As a result of computer simulation, the amplitude of transmitted and scattered waves are presented numerically. The fundamental filtering characteristics of grid-type filter are also shown numerically.
It is reported that frequency component of approximately 0.25Hz of heart rate time series (RSA) is corresponding to the respiratory frequency. In this paper, we proposed that continuous estimation method of respiratory fequency during sleep using the number of extreme points of heart rate time series in real time. Equation for calculation of the method is very simple and the method can continuously calculate frequency by window width of about 18 beats. To evaluate accuracy of proposal method, RSA frequency was calculated using proposal method from the heart rate time series during supine rest. Result, minimum error rate was observed when RSA had time lag for about 11s and error rate was about 13.8%. Result of estimating RSA frequency time series during sleep, it varied regularly during non-REM and varied irregularly during REM. This result is similar as report of previous study about respiratory variability during sleep. Therefore, it is considered that proposal method possible to apply respiratory monitoring system during sleep.
Electromagnetic disturbances for vehicle-mounted radios can be caused by conducted noise currents that flows out from electronic equipment for vehicles to wire-harnesses. In this paper, for reducing the conducted noise currents from electronic equipment for vehicles, we made a simulation and experiment on how ground patterns affect the noise currents from three-layer printed circuit boards (PCBs) with slit-types and plane-type ground patterns. As a result, we could confirm that slits on a ground pattern allow conducted noise currents to flow out from PCBs to wire-harnesses. For the PCBs with plane-type ground and one of three slit-type patterns, on the other hand, both the simulation and examination showed that resonance phenomena occur at unexpected low-frequencies. A circuit analysis revealed that the above phenomena can be caused by the imbalance of a bridge circuit consisting of the trace circuits on the PCB.
Since communication massages in control networks are generated by event-driven way, characteristics of the communication load are intrinsically burst nature. A set of asymptotic approximation equations has been developed in order to calculate the expected values of transmission success rate and transmission delay during the burst load period. Our transient performance analysis has been validated by hundreds of simulation runs using typical system parameters. For a typical burst load model of 100% offered load intensity and 1 - 5 s duration, the calculation error of our analysis of the burst transmission success rate and the burst transmission delay was less than 10% to the simulation result.
Recently, we can easily obtain a fast computer and a digital video camera as their prices go down. In this paper, we describe a method and a system for analyzing performance of tennis players of a given singles tennis game. We assume that a movie of the game has been shot by a digital video camera which is fixed at a place such that the camera could film whole area of the tennis court and the two players, and that we have the sequence of the images in the computer. Using the positions of the players and the ball detected by techniques of image processing and partially by human assistance, we analyzed the game by defining an evaluation function. We made a prototype of a tennis-player-evaluation system by implementing the method. The system appropriately evaluated performances of players of some sample tennis games, although the evaluation function cannot analyze the player's tactics enough.
In this paper, we described various properties of a Generalized Horizon View Camera (GHVC). Original Horizon View Camera (HVC) is a optical system composed of a camera and a mirror. HVC put a single camera on the ground, and the optical axis of the camera is set on the horizon by a mirror. HVC can obtain two kinds of images. One is the image including only objects on the ground in front of the HVC. The other image is including just in front of the HVC. Therefore, it is possible to detect object easily. The GHVC is able to improve a degree of freedom of HVC. In this experiment, we measured a distance to an object by the GHVC. We confirmed that detecting object using the GHVC was effective.
In this study control system of two-degree-of-freedom (2 DOF) robust servo system combined with repetitive controller is proposed for the control of a disk file head-positioning system. For the control of the disk file system both the tracking performance and robust stability are mainly required. In addition the periodic disturbance produced by disk rotation should be considered. The excellent tracking performance and robust stability can be attained by the 2 DOF robust servo system and the adverse effect of the periodic disturbance can be reduced by the repetitive controller. In order to reduce the adverse effects of the periodic disturbance while keeping the excellent closed loop performance the 2 DOF is combined with the repetitive control. Proposed control system is applied to the forcussing control system of the CD-R experimental system. Experimental results show the usefulness and effectiveness of the proposed control system.
In recent years, as a result of a large amount of greenhouse gas emission, atmosphere temperature at ground level gradually rises. Therefore the Kyoto Protocol was adopted to solve the matter in 1997. By the energy-saving law amended in 1999, it is advisable that an escalator is controlled to pause during no user. Now a photo-electric sensor is used to control escalator, but a pole to install the sensor is needed. Then, a new type of approach detection sensor using laser diode, CCD camera and CPLD, which can be built-in escalator, has been studied. This sensor can derive the irradiated area of laser beam by simple processing in which the laser beam is irradiated in only the odd field of the interlace video signal. By second order derivative of laser irradiated area, this sensor can detect only the approaching target but can not detect the target which crosses and stands in the sensing area.
In a state feedback control, all state variables should be detected accurately and these informations should be utilized without time delay. Then if some of state variables cannot be detected directly, these have to be estimated from output signals and input signals by observers. For the synthesis of Luenberger type observer, plant parameters must be exactly known. Therefore, when some of plant parameters are varied or unknown, Luenberger type observer cannot be utilized. In this paper, a new observer synthesis method with insensitivity (zero sensitivity) to parameter variations of the plant is discussed. On the basis of the zeroing concept and the quadratic stabilization method via linear control strategy, the existence condition of the observer which is related to a class of variations of the plant parameters is given.
In this paper, use of portable music players with recording function to measure the environmental noise for long hours is proposed, and the method of specific operation and measurement accuracy are discussed. Specifically, players are used to record the sound, and the recorded sound is analyzed on personal computer to calculate the noise evaluation function, such as A-weighted sound pressure level or equivalent continuous level. To check the accuracy, continuous recording for 24 hours at 20 sites, targeting at the sounds received in general residence, was carried out and equivalent continuous levels over a fixed period of ten minutes were calculated. As a result, difference to the measured value by the sound level meter turned out to be less than 0.5 dB (0.26 dB with rms) when built-in microphone of sound level meter was used to record (the AC output). For this reason, when used in combination with sound level meter, back-up usage with actual sound recording is expected. Also, difference to the measured value by the sound level meter was less than 2.0 dB (1.24 dB with rms), and it is considered fully usable when portable players are used alone for such as preliminary survey.
This paper describes a position measurement system for a mobile microrobot used in a desktop manufacturing system. Three line laser projectors are carried by linear stages, which are placed above the microrobot. The mobile microrobot carries three optical devices which receive laser beams. The position and orientation of the microrobot is determined by the position of the linear stages. The measurement accuracy in 8 mm × 8 mm area was about 5 μm, and that in 50 mm × 50 mm area was about 50 μm.
In this paper, we propose a new design method of frequency dependent optimal servo system for the positioning of flexible structures. In order to reduce the sensor costs and to suppress spillover phenomena which are caused by ignored elastic modes of the plant, we introduce a pre-filter into an input, which possesses low pass characteristics. The proposed method enables to design specified characteristics of the pre-filter and to assign poles to desirable locations of a closed loop system exactly while keeping optimality. Some results of experiments are given in order to verify the usefulness of our method.
This paper presents an assisting method for positioning task using flexible master slave manipulator. The proposed assisting method is a unilateral control consisting of input shaping compensator in the master side and direct acceleration feedback of the tip of slave arm in the slave side. Notch filter is used as the input shaping compensator to eliminate vibration frequency from operating force signal. The effectiveness of the proposed method is verified from standpoints of maneuverability and operator's feeling. The former is based on the evaluation of the time responses and the success time, and the latter the subjective evaluation of an operator using semantic differential method and principal component analysis.
Recently, a lot of researches on geographic information models for handling events have been proposed. However, many of researches are application-oriented. Namely, they are not suitable to represent a phenomenon spreading broadly in the geographic space such as earthquakes, typhoons, and so on. In this paper, we propose a new model for handling events in a distributed geographic information system. In our model, event information and geographic information are represented independently, and they are associated dynamically according to the viewpoint of users for an event.
The text classification is an important subject in the data mining. For the text classification, several methods have been developed up to now, as the nearest neighbor analysis, the latent semantic analysis, etc. The k-nearest neighbor (kNN) classification is a well-known simple and effective method for the classification of data in many domains. In the use of the kNN, the distance function is important to measure the distance and the similarity between data. To improve the performance of the classifier by the kNN, a new approach to combine multiple distance functions is proposed here. The weighting factors of elements in the distance function, are computed by GA for the effectiveness of the measurement. Further, an ensemble processing was developed for the improvement of the classification accuracy. Finally, it is shown by experiments that the methods, developed here, are effective in the text classification.
This paper proposes a method of a background noise estimation based on the tensor product expansion with a median and a Monte carlo simulation. We have shown that a tensor product expansion with absolute error method is effective to estimate a background noise, however, a background noise might not be estimated by using conventional method properly. In this paper, it is shown that the estimate accuracy can be improved by using proposed methods.
We report on a novel sensing method in the terahertz region using metallic mesh. Conventionally, the band-pass filter property of a metallic mesh can be adjusted by changing the mesh geometrical parameters. However, the band-pass filter parameters also depend on the refractive index of the medium in the vicinity of the mesh openings. To inspect this effect as a potential measurement principle, we calculated the electric field distribution around the metallic mesh and analyzed the frequency characteristics due to a sample attached to the metallic mesh using the Finite Difference Time Domain method. For bio-molecular sensing, the Electrospray Deposition method was applied in order to spray a uniform layer of protein over a metallic mesh. We observed a correlation between the quantity of protein and the transmission characteristics of the metallic mesh.
Previous studies of image restoration for noise images were based on a mask processing. These conventional noise removal methods based on the mask processing have an issue of defining degradation to accompany a spacial processing. In this paper, we propose a graininess suppression method based on edge shape. In this method, we detect edges from an noise image and perform graininess suppression for this image based on edge information. On the edge detection, we execute an image transformation for an image that enables us to extract edge by making principal component images. Moreover, we use the canny edge detection operator with can detect a weak edge that relates to a real edge, and do not detect a lie edge. In the suppression process, we use Wiener filter that can restore an noise image without making a complete edge map and the original signal map. We demonstrated the effectiveness of the present method for the noise added images and confirmed it by means of computer simulation.
In industrial processes represented by petroleum and refinery processes, it is necessary to establish the performance-driven control strategy in order to improve the productivity, which the control performance is firstly evaluated, and the controller is reconstructed. This paper describes a design scheme of performance-adaptive PID controllers which are based on the above control mechanism. According to the proposed control scheme, the system identification works corresponding to the result of modeling performance assessment, and PID parameters are computed using the newly estimated system parameters. In calculating the PID parameters, the desired control performance is considered. The behaviour of the proposed control scheme is numerically examined in some simulation examples.
This paper proposes a useful method driving the electric vehicle by EMG signals (Electromyographic signals) which are filtered on the basis of frequency components which change with muscle contraction. This method estimates strength of muscular tension by a single EMG signal. By our method, user is able to control speed of the electric vehicle by strength of muscular tension. The method of speed control may give user good or bad operation feeling in the meaning of SD (Semantic Differential) method and factor analysis. The operation feeling is evaluated by experiment on EMG interface in cases of using filters or not. As a result, it is shown that operation feeling is influenced by this method.
This paper considers the control problem of a popular magnetic levitation system, which is open-loop unstable and strongly nonlinear associated with the electromechanical dynamics. The system dynamics is governed by a third-order nonlinear differential equation. The overall controller is designed through a backstepping manner by combining both the robust control and disturbance observer techniques. With the help of nonlinear damping terms, the input-to-state stability property of the overall nonlinear control system is proved, which leads to a major academic contribution of construction of a theoretically guaranteed robust nonlinear controller with disturbance observer for the first time in the literature. Experimental results are included to show the excellent position tracking performance of the designed control system.
Thermal distribution in thermal processes which is observed in both steady and transient states causes inferior quality. Thus, uniform temperature control is extremely required in many industrial application fields for quality improvement. In this paper, a novel control design method for uniform heating based on the temperature difference model (TDM) is proposed. The design procedure consists of strong coupling by temperature difference feedback and set point regurator. The effectiveness of the proposed controller is evaluated using an experimental heat plate.
We propose a novel data structure, called the DIMD-tree, that provides efficient successive spatial searches in GPS navigation systems, mobile phone systems and so forth. The DIMD-tree can be applicable for the geographic data management of positioning systems as well as the query processing for current and anticipated future positions of moving objects. The basic idea introduced in the DIMD-tree is direct indexing into a node or leaf which includes the predicted position of a moving object. The performances of the DIMD-tree are evaluated by simulation tests.
In order to search out some documents on a specific topic from a huge amount of documents on the Internet, we sometimes use a Web site that is called a search engine and retrieve documents by using a keyword. However, since a lot of pages are obtained by a keyword, it is difficult to find out the page that we really want from the obtained pages. In this paper, we propose a system supporting to look for web pages on the Internet that a user desires to find. The system actively collects web pages of a topic that relates to a keyword specified by a user and presents them to the user. The experimental result shows the effectiveness of the proposed system.
Many evolutionary computation methods have been proposed and applied to real world problems. But gradient methods are still effective in problems involving real-coded parameters. In addition, it is desirable to find not only an optimal solution but also plural optimal and semi-optimal solutions in most real world problems. Although a hybrid algorithm combining Immune Algorithm (IA) and Quasi-Newton method (QN) has been proposed for multiple solution search, its memory cell control sometimes fails to keep semi-optimal solutions whose evaluation value is not so high. In addition, because the hybrid algorithm applies QN only to memory cell candidates, QN can be used as local search operator only after global search by IA. This paper proposes an improved memory cell control which restricts existence of redundant memory cells, and a QN application method which uses QN even in early search stage. Experimental results have shown that the hybrid algorithm involving the proposed improvements can find optimal and semi-optimal solutions with high accuracy and efficiency even in high-dimensional multimodal functions involving epistasis.
The electric power liberalization will expand. The method of judging the service selection is requested by customers. The method of comparing each energy unit price based on the average demanded is general. However, there are risks in customer's energy demand in the future. In the supply contract, there is freedom of contract changes according to demand changes. By this contract changes customers can avoid the risks. In this paper, we think that there was value in contract changes and we proposed the new method for analyzing the economy of this value.
There is a new demand in the field of tissue engineering for evaluation technology of extracellular matrix because the extracellular matrix plays an important role in the function of skeletal tissue such as articular cartilage. We previously proposed a noninvasive method of viscoelastic characterization of tissue phantom, based on the photoacoustic measurement. The purpose of this study was to verify the applicability of the photoacoustic measurement method for monitoring of the development of extracellular matrix using tissue engineering technology. The decay times measured by the photoacoustic method were varied with culture periods when tissue-engineered articular cartilages with various culture periods (-12 weeks) were used as samples. Tissue-engineered cartilage cultured for a long period showed shorter decay times, indicating that the samples approached an elastic solid from a rheological viewpoint. By comparison between biochemical analyses and biomechanical studies, we proved that the photoacoustic signal was a good indicator for evaluating extracellular matrix formation because the change of the photoacoustic decay times would reflect the production of an extracellular matrix.
We show that infrared absorption spectroscopy can probe the adsorption and desorption process of Au nanoparticles onto silica surface from colloidal suspension. When the Au nanoparticles come into the evanescent field of the infrared (IR) beam in attenuated total reflection (ATR) geometry, IR vibrational signal is detected due to the surface enhanced IR absorption. Quantitative analysis of the adsorption kinetics is possible by monitoring the time dependence of the IR signals.