A semicylindrical microstrip applicator system is proposed and designed, both for microwave heating and for noninvasive temperature estimation, in application to hyperthermia treatment. The experimental results showed that the system functions both as a heating device and as a means of noninvasive temperature estimation. Therefore, electrical switching of these two functions makes the system realize both heating and temperature estimation. These functions reduce the pain of hyperthermia therapy for patients. The system is constructed of a water-loaded cylindrical applicator. Thus, the whole system can be made compact compared to conventional applicators. This improvement allows for various merits, such as realizing a surface cooling effect and decreased leakage of electromagnetic (EM) waves. When the applicator is set as an array arrangement, the system can be used as a microwave heating device. The penetration depth can be varied by adjusting phases of the EM wave radiated from each applicator. The experimental results at 430 MHz showed that semicylindrical microstrip applicators can be expected to be valid for tumor heating at depths within 55 mm. Moreover, by measuring transmission power between the two applicators, the system can be used to estimate temperature inside the medium. The transmission power which was measured in the frequency domain was converted in the time domain. By such a method, temperature distribution was calculated by solving simple simultaneous primary equations. The results of the temperature estimation show that the number of estimated temperature segments which have an error within 0.5 is 28 out of 36. The system can be easily used as a temperature measuring applicator as well as a heating applicator.

If one of the R, L, or C Parameter of an RLC parallel circuit is changed periodically, under certain conditions, an oscillation called Parametric oscillation occurs. If one of remaining circuit elements is made to change due to an external cause (e.g. an external electric or magnetic field), then the parametric oscillation will experience some modulation. This modulation process and the subsequent demodulation can be exploited to create several types of sensors. In this letter, we describe the features of a new parametric magnetic speed sensor and its application in Induction motor robust control.

Binary decision diagrams (BDD's) are graph representations of Boolean functions, and at the same time they can be regarded as a computational model. In this paper, we discuss relations between BDD's and other computational models and clarify the computational power of BDD's. BDD's have the property that each variable is examined only once according to a total order of the variables. We characterize families of BDD's by on-line deterministic Turing machines and families of permutations. To clarify the computational power of BDD's, we discuss the difference of the computational power with respect to the way of reading inputs. We also show that the language TADGAP (Topologically Arranged Deterministic Graph Accessibility Problem) is simultaneously complete for both of the class U-PolyBDD of languages accepted by uniform families of polynomial-size BDD's and the clas DL of languages accepted by log-space bounded deterministic Turing machines. From the results, we can see that the problem whether U-PolyBDD U-NC1 is equivalent to a famous open problem whether DL U-NC1, where U-NC1 is the class of languages accepted by uniform families of log-depth constant fan-in logic circuits.

Pitch frequency is a basic characteristic of human voice, and pitch extraction is one of the most important studies for speech recognition. This paper describes a simple but effective technique to obtain correct pitch frequency from candidates (pitch candidates) extracted by the short-range autocorrelation function. The correction is performed by a neural network in consideration of the time coutinuation that is realized by referring to pitch candidates at previous frames. Since the neural network is trained by the back-propagation algorithm with training data, it adapts to any speaker and obtains good correction without sensitive adjustment and tuning. The pitch extraction was performed for 3 male and 3 female announcers, and the proposed method improves the percentage of correct pitch from 58.65% to 89.19%.

A simple method for separating the dissipation factors associated with both conductor losses and dielectric losses of printed circuit boards in microwave frequencies is presented. This method utilizes the difference in dependence of two dissipation factors on the dimensions of bounded stripline resonators using a single printed circuit board specimen as a center strip conductor. In this method, the separation is made through a procedure involving the comparison of the measured values of the total dissipation factor with those numerically calculated for the resonators. A method, which is based on a TEM wave approximation and uses Green's function and a variational principle, is used for the numerical calculation. Both effective conductivity for three kinds of industrial copper conductor supported with a substrate of polymide film and dielectric loss tangent of the substrates are determined using this method from the values of the unloaded Q measured at the 10 GHz region. Radiation losses from the resonator affecting the accuracy of the separation are discussed, as well as the values of the effective conductivity of metals on the polyimide substrate which is calculated using the above method. The resulting values of the effective conductivity agree with those using the triplateline method within 10%.

ADTs (Abstract Data Types) have been known as a promising feature for extending the database applications to CAD/CAM and other engineering areas. This extension has brought a new dimension to query optimization. Conventional query optimization methods, which considers only joins as the dominant cost factor, are based on the belief that the executions of selections and projections basically take no time. However, in databases that support ADTs, this may not be true since the execution of a selection involving ADT functions may be very time-cosuming. Thus selections with ADT functions should not be considered as inexpensive operations in queries, and the conventional optimization heuristics should be enhanced to correspond to the appearance of the queries of this kind. In this paper, we show the possibility that semijoins can be used as an effective means to reduce the number of evaluations of an ADT function and consequently optimize queries containing expensive ADT selections. We suggest the enhancement of an conventional optimization heuristics by adding a semijoins pre-stage which is an additional component corresponding to expensive ADT selections. By this way, the applicable range of the conventional heuristics are extended to hold the ability of handling queries with ADT functions. Several optimization algorithms are given and some simulation results show the effectiveness of our methods.

This paper presents an optimal filtering algorithm using the covariance information in linear continuous distributed parameter systems. It is assumed that the signal is observed with additive white Gaussian noise. The autocovariance function of the signal, the variance of white Gaussian noise, the observed value and the observation matrix are used in the filtering algorithm. Then, the current filter has an advantage that it can be applied to the case where a partial differential equation, which generates the signal process, is unknown.

An Ordered Binary Decision Diagram (BDD) is a graph representation of a Boolean function. According to its good properties, BDD's are widely used in various applications. In this paper, we investigate the computational complexity of basic operations on BDD's. We consider two important operations: reduction of a BDD and binary Boolean operations based on BDD's. This paper shows that both the reduction of a BDD and the binary Boolean operations based on BDD's are NC1-reducible to REACHABILITY. That is, both of the problems belong to NC2. In order to extend the results to the BDD's with output inverters, we also considered the transformations between BDD's and BDD's with output inverters. We show that both of the transformations are also NC1-reducible to REACHBILITY.

This paper describes the relaxation-based algorithms with the dynamic partitioning technique for bipolar circuit analysis. In this technique, a circuit is partitioned dynamically based on the consideration of the operating region of specified bipolar devices. This technique has been used already in the waveform relaxation method. In this paper, the dynamic circuit partitioning technique is implemented in the Iterated Timing Analysis (ITA). First, the dynamic partitioning method and its validity are described. Next, the present ITA is applied to the transient simulation of several digital bipolar circuits and compared with the waveform relaxation method.

A method is presented to perform image segmentation by accumulatively observing apparent motion in a long image sequence of a dynamic scene. In each image in the sequence, locations are grouped into small patches of approximately uniform optical flow. To reduce the noise in computed flow vectors, a local image motion vector of each patch is computed by averaging flow vectors in the corresponding patches in several images. A segment contains patches belonging to the same 3-D plane in the scene. Initial segments are obtained in the image, and then an attempt to merge or split segments is iterated to update the segments. In order to remove inherent ambiguities in motion-based segmentation, temporal coherence between the local image motion of a patch and the apprent motion of every plane is investigated over long time. In each image, a patch is grouped into the segment of the plane whose apparent motion is temporally most coherent with the local image motion of the patch. When apparent motions of two planes are temporally incoherent, segments of the planes are retained as individual ones.

This paper presents an experimental study on the penetration characteristics of submillimeter waves in biological tissues and material. The measured values of the penetration depth in excised natural muscle, fat, and aqueous solution of protein, bovine serum albumin (BSA), over the wavelengths of 281 through 496µm are presented. Penetration depths at these wavelengths are 0.11-0.17mm in the natural pork muscle, and 0.69-0.98mm in the natural pork fat, and are the larger at the longer wavelengths. The values vary considerably from sample to sample. Since the measurement of the penetration depth in this study is shown sufficiently reproducible, the variation of the measured penetration depth is attributed to the variation of natural tissues such as that in water content. It is found that the penetration depth of submillimeter waves in aqueous solution of BSA depends almost linearly on the amount of protein content in the solution, and that the typical values of the penetration depth in the natural muscle roughly agree with that in the 35% aqueous solution of BSA in the submillimeter-wave region.

A simple adapter de-embedding method is presented in a six-port calibration process using only one sliding load and one standard short. Adapter de-embedding is performed to extract the S-parameters of the adapter from the six-port system parameters. The concept of this method is based on the relations between the S-parameters and the Fourier coefficients of the periodic return loss of the adapter. To complete the de-embedding procedure, there are two measurement steps: one is return loss measurement with the sliding load, and the other, sidearm power measurement with the standard short. Using these measured values, unique solutions of the S-parameters are determined. A computer-controlled six-port with 2.4 mm coaxial-type connector was designed for calibration using a waveguide-type sliding load over the frequency range of 8.5-12.0 GHz. Through experiments, the adapter for joining two unlike connector types was measured. Then the reflection coefficients of the adapter with the sliding load measured by the calibrated six-port and those calculated from the S-parameters were compared with each other. As a result, an overall good agreement with standard deviation of less than 0.1% was found at all setting frequencies. One of the main features of the method is that the S-prameters of a two-port as well as the system parameters of a six-port can be determined by means of simple scalar measurement.

Physical optics (PO) is an approximation method for high-frequency scattering and diffraction problems. But PO fields are inaccurate in the shadow region where the source is screened by the scatterer. It has been difficult to extract the mechanism of this error because PO includes numerical integration. In 2-D problems, PO fields are analytically and accurately expressed in terms of PO equivalent edge currents (PO-EECs) which represent the leading contributions of PO original integration. Comparison of PO in this form and geometrical theory of diffraction (GTD) which gives accurate fields in the shadow region, clarifies the cause of PO errors. For a scatterer with a corner, PO errors are mainly due to the rays emanating from the invisible edges. For a curved surface scatterer, the contributions penetrating the scatterer are small and main PO errors generally consist in PO-EECs itself.

An improvement of Q evaluation is discussed. The Resonance Curve Area method was confirmed to give a deviation in the order of 6104. The result was three times more accurate than the widely known Q evaluating method which utilizes the cursor function installed in a network analyzer. A discussion is also made on the physical validity of the RCA method. It is shown that the application of the RCA method improves the accuracy of the cavity perturbation method. Actual measurements have shown that the deviation of dielectric constant is less than 1% and that of the loss tangent is less than 3%, in the order of 104. The accuracy of the RCA method was estimated to be three times that of the conventional cavity perturbation technique. The consistency of the perturbation with other methods has also confirmed. The accuracy comparison to more accurate formulae derived from a rigorous solution have shown that the difference is sufficiently small.

In 1985, Kues et al. (Bioelectromagnetics, 6, pp.177-188, 1985) reported that corneal endothelial abnormalities were observed after a 4-hour exposure of anesthetized monkey eyes to 2.45GHz CW. We have traced their experimental study without anesthetization. Although we irradiated with power density exceeding the threshold of 30mW/cm2 obtained by them, we could not observe the same abnormalities as they did.

We developed an automatic data processing algorithm for a ground-probing radar which is essential in analyzing a large amount of data by a non-expert. Its aim is to obtain an optimum result that the conventional technique can give, without the assistance of an experienced operator. The algorithm is general except that it postulates the existence of at least one isolated target in the radar image. The raw images of underground objects are compressed in the vertical and the horizontal directions by using a pulse-compression filter and the aperture synthesis technique, respectively. The test function needed to configure the compression filter is automatically selected from the given image. The sensitivity of the compression filter is adjusted to minimize the magnitude of spurious responses. The propagation velocity needed to perform the aperture synthesis is determined by fitting a hyperbola to the selected echo trace. We verified the algorithm by applying it to the data obtained at two test sites with different magnitude of clutter echoes.

This paper theoretically and experimentally investigates the mutual coupling between two ports of dual slot-coupled circular microstrip antennas. Presented are the effects of feed configuration, slot length, slot offset from the circular disk center, circular disk radius and the dielectric constant of the feed substrate on the mutual coupling. Based on these results, the antenna with low mutual coupling was designed. The mutual coupling of under -35dB at the resonant frequency was obtained.

The effect of intersymbol interference resulting from non-matched receiver filtering on the bit error rate (BER) performance of π/4-DQPSK systems recently adopted in the North American and Japanese digital cellular standards, is analyzed in Rayleigh fading. With a Gaussian or a Butterworth (of order N, 2N10) receiver filter, the BER performance is found to degrade by only a small fraction of a decibel from the performance with ideally matched receiver filters. A 4th-order Butterworth receiver filter leads to BER curves which almost coincide with those of the ideally matched filtering condition.

We describe a new water sensing system for optical fiber cable networks. This system consists of optical fibers, water sensors and an OTDR (Optical Time Domain Reflectometer). The water sensor contains material which swells on contact with water and bends the optical fiber. The OTDR monitors the optical loss increase caused by this fiber bending and determines its location. In this system it is very important to determine the loss increase caused by the water sensor in terms of the OTDR performance. Therefore, we clarified the relationship between the water sensor structure and the increase in loss. Based on this study, we fabricated a sensor which causes a 5dB loss increase. The measured value is very close to the calculated value.

This paper surveys the researches on biological and electeromagnetic environments in RF (radio frequency) and microwave regions in Japan. Publicized research reports on biological objectives, evaluation of exposure rate, electromagnetic environments and guideline for the protection from radio wave nuisances are briefly introduced. Some researches on the evaluation of the exposure rate caused by the near field effect of portable radio transceiver are reviewed. Radio frequency exposer protection guidelines in Japan are also described.