In order to increase the reliability of Surface Acoustic Wave (SAW) filters, a robust optimum design technique is presented. The frequency response characteristics of SAW filters are governed primarily by their geometrical structures, i.e., the configurations of Interdigital Transducers (IDTs) and reflectors fabricated on piezoelectric substrates. For deciding desirable structures of SAW filters through the computer simulation, conventional design techniques utilize the equivalent circuit model of IDT. However, they have rarely considered the accuracy of the underlying model that may be spoiled by the dispersion of circuit parameters. In this paper, considering the errors of these parameters, the robust optimum design of SAW filters is formulated as a constrained optimization problem. Then, a penalty function method combined with an improved variable neighborhood search is proposed and applied to the problem. Computational experiments conducted on a practical design of a resonator type SAW filter demonstrate the usefulness of the proposed method.
Ti4+ and Er3+ LiNbO3 films on the z-cut congruent LiNbO3(CLN) wafer substrates were grown by using a sol-gel method. The orientation relationships between films and substrates were determined by x-ray diffraction, Raman spectroscopy, scanning electron microscope(SEM), and the results showed that (006) oriented LiNbO3 epitaxial layers with parallel epitaxial relationships could be grown on a z-cut CLN wafer substrate. Er3+ exhibited an emission at 1.53μm and efficient luminosity in the visible light could be observed from Ti:Er:LiNbO3 films. The strongest luminosity was observed for the films with Ti4+concentration 1.5 mol% and Er3+concentration 0.05 mol% Ti:Er:LiNbO3 films.
We have an assumption that both X-axis and Y-axis of a receiving antenna (5m in diameter, X-band) for earth observation satellite are not exactly at right angles to each other, and that an antenna mount is rotated. In this paper, we make a proposal on antenna alignment calibration method of a receiving ground station for earth observation satellite. And, we conduct a test of an earth observation satellite reception by using the calibration parameters derived from our proposal. Through the test, we confirm the effectiveness of our proposal. Our proposal using virtual six-axis antenna alignment model is a method which corrects an antenna drive angle by using the sun as a signal source. As a result, we do not need to do mechanical alignments which are dangerous operations, in an antenna drive system. Also, we do not need to own , manage and maintain collimation facilities. As our proposal is realizable by adding a RF power meter to a receiving system, it can be said a safer and cheaper method.
Ultrafast all optical switching by use of pulse trapping in birefringent optical fiber is demonstrated both experimentally and numerically. The wavelength of the control soliton pulse and the trapped soliton pulse is shifted to satisfy the condition of group-velocity matching. Furthermore, the energy of trapped pulse is increased through Raman gain of control pulse. Only a signal pulse among three pulses with temporal separation of about 1.2 ps is successfully picked off. The repetition frequency corresponds to 0.83THz. The spectrogram of the optical switching is directly observed using the X-FROG technique.
This paper proposes a novel signal recovery technique for multiuser multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems using a combination of blind source separation(BSS) and semi-blind method from the frequency bin(FB) viewpoint. A pre-filter is applied on each user signal before OFDM signal. The pre-filter converts user signals into transmitted signals which possess a correlation structure. At the receiver, we firstly recover signals using existing BSS algorithm at the first FB and second FB in OFDM systems, and resolve the indeterminacies nature of BSS algorithm employing a few pilot symbols at the first FB. Then separated signals at the second FB can be utilized as reference signals for the recovery of signals at next adjacent FB due to the correlation structure of transmitted signals. Also the validity of the proposed method is demonstrated by computer simulations.
A Radio on Fiber (ROF) technique has a great potential in wireless communication systems. In this paper, we performed fundamental examination of microwave wireless access systems based on Radio on Fiber. First, we designed and constructed examination systems applying dual band (2.4GHz and 5GHz) multi service transmission systems and confirmed to have sufficient performance by transmission experiment. Then, application of FP-LD (Fabry Perot Laser Diode) was considered in order to reduce the system cost, and most degradation of the transmission characteristics was not observed when FP-LD was used. Finally, BIDI (Bi-directional) module which integrated LD and PD within one package was made for further cost reduction. By measuring the transmission performance, applying BIDI module to ROF systems was shown to be effective.
We have proposed Horizon View Camera (HVC), which is a unique system of the object detection by a single camera and has some unique characteristics. HVC is to put a single camera on the ground, and the optical axis of the camera is directed toward the horizon by using a mirror. HVC can obtain two kinds of images. One is the image including only the object on the ground. Therefore, it is possible to detect objects easily. We have shown its effectiveness by measuring distances to objects using the obtained images from HVC with straight motions. Moreover, we proposed HVC-90 that is more effective system than the original HVC for object detection. HVC-90 can detect objects in various motions. In these camera systems, we used characteristics obtained from moving HVC mainly. In this paper, moreover, we develop a unique input interface by using characteristics from standing HVC. We made a potable piano as an example of this interface, and show its effectiveness.
We have investigated Kansei Content that appeals maker's intention to viewer's kansei. An SD method is a very good way to evaluate subjective impression of image-contents. However, because the SD method is performed after subjects view the image-contents, it is difficult to examine impression of detailed scenes of the image-contents in real time. To measure viewer's impression of the image-contents in real time, we have developed a Taikan sensor. With the Taikan sensor, we investigate relations among the image-contents, the grip strength and the body temperature. We also explore the interface of the Taikan sensor to use it easily. In our experiment, a horror movie is used that largely affects emotion of the subjects. Our results show that there is a possibility that the grip strength increases when the subjects view a strained scene and that it is easy to use the Taikan sensor without its circle base that is originally installed.
Self tuning control (STC) is a control technique to adjust the parameter of the on-line controller which adapts itself when plant parameter changes. There are minimum-variance control (MVC), generalized minimum-variance control (GMVC), generalized predicted control (GPC), and so on as a effective way of design STC. The structure of MVC and GMVC is especially easy and manageable. It is necessary to use MVC that plant is minimum phase system and stable in the discrete time-domain. But, generally actual controlled system is continuous time. Then, when digitizing is given, it sometimes becomes non-minimum phase system. And if we set up sampling time very small, MVC controller has unstable poles. In this paper, we propose that how to design MVC for plant which is stable and minimum phase system in continuous time domain by introducing a delta-operator and weight adjustment of the cost function. Then, we study about stability.
In the evaluation of sound environment around a main line, it is necessary to estimate the sound levels at evaluation points based on the observations at a reference point. In this study, a method to estimate system parameters reflecting several correlation information between both evaluation and reference points based on the observations contaminated by a background noise is first derived. Next, a method for estimating precisely the specific signal for the sound environment with unknown structure and an observation noise of unknown statistical properties is theoretically proposed. The effectiveness of the proposed theory is confirmed experimentally by applying it to actual traffic noise data at main line.
We propose a method to improve the performance of R-learning, a reinforcement learning algorithm, by using multiple state-action value tables. Unlike Q- or Sarsa learning, R-learning learns a policy to maximize undiscounted rewards. Multiple state-action value tables cause substantial explorations as needed and make R-learnings to work well. Efficiency of the proposed method is verified through experiments in simulation environment.
This paper describes the emotional evaluation of a frisky robot that weaves around its human owner; the evaluation is based on the SD (Semantic Differential) method and the RRV(R-R wave variance) method using electrocardiograms (ECG) as the biosignal source. The SD method is effective to measure emotion, and the RRV method is suitable for investigating the physiological state from the heartbeat. The SD method shows that humans show a significant response only when the robot weaves, not when it simply shadows the human. Furthermore, we revealed that these methods are correlated which suggests that the RRV method supports real time evaluation.
In recent years, the adaptive Volterra filter (AVF) based on discrete Volterra series has been used to identify a nonlinear system, remove nonlinear distortion etc. Since AVF is an extension of the conventional linear digital filters, the algorithms used in linear filters are easily used in AVF, and AVF is sufficiently approximate to the complicated systems due to its general function expansion. However, AVF has a problem that the calculation work becomes extremely large for long memory length, or for filtering high-order nonlinear characteristic. This paper presents a type of parallel adaptive Volterra filter (PAVF) to decrease the calculation complexity. Finally, to illustrate the effectiveness of the proposed method, the results of computer simulation with recursive least squares (RLS) algorithm are presented.
This article analyzes and evaluates the R&D strategy for advanced power generation technologies, such as natural gas combined cycles, IGCCs (Integrated coal Gasification Combined Cycles), and large-scale fuel cell power generation systems with a mixed-integer programming model. The R&D processes are explicitly formulated in the model through GERT (Graphical Evaluation and Review Technique), and the data on each required time of R&D was collected through questionnaire surveys among the experts. The obtained cost-effective strategy incorporates the optimum investment allocation among the developments of various elemental technologies, and at the same time, it incorporates the least-cost expansion planning of power systems in Japan including other power generation technologies such as conventional coal, oil, and gas fired, and hydro and wind power. The simulation results show the selection of the cost-effective technology developments and the importance of the concentrated investments in them. For example, IGCC, which has a relatively high thermal efficiency, and LNG-CCs of the assumed two efficiencies are the cost-effective investment targets in the no-CO2-regulation case.
Due to the deregulation of financial industry, the branches in banking industry need to shift to the sales-oriented bases from the operation-oriented bases. For corresponding to this movement, new banking branch systems are being developed. It is the main characteristics of new systems that we bring the form operations that have traditionally been performed at each branch into the centralized operation center for the purpose of rationalization and efficiency of the form operations. The branches treat a wide variety of forms. The forms can be described by common items in many cases, but the items include the different business logic and each form has the different relation among the items. And there is a need to develop the client application by user oneself. Consequently the challenge is to arrange the development environment that is high reusable, easy customizable and user developable. We propose a client application architecture that has a loosely coupled component connection method, and allows developing the applications by only describing the screen configurations and their transitions in XML documents. By adopting our architecture, we developed client applications of the centralized operation center for the latest banking branch system. Our experiments demonstrate good performances.
The electric power market of Japan has been locally monopolized for a long time. But, like many countries, Japan is moving forward with the deregulation of its electric power industry so that any power generation company could sell electric power in the market. The power price, however, will fluctuate inevitably to balance the power supply and demand. A new appropriate market design is indispensable when introducing new market mechanisms in the electric power market to avoid undesirable results of the market. The first stage of deregulation will be the competition between an existing large-scaled power utility and a new power generation company. In this paper we have investigated the wholesale market with competition of these two power companies based on a simulation model approach. Under the competitive situation the effects of exogenous disturbance may bring serious results and we estimated the influence on the market when the price of fossil fuel rises. The conclusion of this study is that several types of Nash equilibriums have been found in the market: the larger the new power generation company becomes, the higher the electricity price under the Nash equilibriums rises. Because of the difference in their structure of generation capacity, the existing large-scaled power utility gets more profit while the new power generation company loses its profit when the price of fossil fuel rises.
In this paper, Local search methods for “Tree Chromosome Structure in a Genetic Algorithm to Identify Functions" which succeeds in function identifications are proposed. The proposed method aims at the identification success rate improvement and shortening identification time. The target functions of identification are composed of algebraic functions, primary transcendental functions, time series functions include a chaos function, and user-defined one-variable funcions. In testing, Kepler's the third law is added to Matayoshi's test functions(7)-(9). When some functions are identified, the improvement of identification rate and shortening time are indicated. However, we also report some ineffectual results, and give considerations.
Approximately 300 nm-thick Al-doped transparent conducting zinc oxide films (AZO(Al2O3:1.5 wt.%)) have been deposited on glass and PVC substrates by a pulsed laser deposition (PLD) using ArF excimer laser (λ=193 nm) with energy of 40-100 mJ at the repetition frequency of 50 Hz. When fabricated with the laser energy of 40-100 mJ, similar characteristics of electrical properties and optical transmittance were obtained for the AZO films deposited on glass or PVC substrates. Namely, the lowest resistivity obtained was 6.34×10-4Ω·cm and an average optical transmittance was more than 80 % in the visible range. But, when prepared with the laser energy of 80-100 mJ, surface roughness for the AZO films fabricated on PVC substrates decreased compared to the films deposited on glass substrates. Moreover, for the AZO films fabricated on PVC substrates, an average optical transmittance in the visible range was reduced to 30-50 %.
A novel structure of an all optical clock signal extraction circuit for NRZ signals is proposed. Polarization independent operation is achieved by the bi-directional use of a Mach-Zender interferometer for optical XOR operation. Applying the circuit to experiments where 40-Gbit/s NRZ signal is transmitted through 120-km SMF, the function of the proposed circuit is confirmed.