This paper proposes a method for producing a soft scenario" that coordinates highly individualized and mixed-initiative tutoring with strategic dialogue composed of semantically consecutive topics. The soft scenario is generated in three steps. The first step generates an outline plot of the scenario at the beginning of learning. The outline is composed of parts of domain knowledge to be taught and their sequence. A knowledge representation model, called MHM, and a method to represent author's teaching strategy, called a strategy graph, are introduced and used for generating the outline plot. The second step generates detailed parts of the scenario at the time to punctuate learning. Detailed planning is composed of two portions. One portion is to modify the pre-generated outline plot if the results of learning do not agree with the forecast. The other portion decides a teaching paradigm and a topic. A method of identifying student error origins, a teaching paradigm called adaptive guiding and information about leaning situation are presented and used for detailed planning of soft scenario together with a resolution tree of a given topic and compatibility of a topic to paradigm. The third step, which is not included in this paper, creates a dialogue part of the scenario according to a dialoguing strategy by using the previous context, and accords natural language outputs with graphical outputs.

A framework for the visual representation of three-dimensional free-form curved surfaces based on a special class of surface curves, herein called the surface structure curves, is in progress. By analyzing their properties, we attempt to construct a basis for describing the topographical structures of curved surfaces which give a global description of the surface geometry. Surface structure curves are a set of surface curves defined by using viewpoint-invariant features-surface curvatures (and their gradients and asymptotes) from differential geometry. From these surface structure curves, surface sketches by means of the topographical structure of ridge lines, valley lines and the enclosing boundaries of bumps and dents can be inferred. This paper proposes a view-point invariant representation scheme which provides a smooth surface sketch",--a natural parameterization of free-form curved surfaces. We define three types of surface structure points and five types of surface structure curves in terms of zero-crossings, asymptotes and gradients of the Gaussian and mean curvatures. We discuss their properties and usefulness in edge based segmentation and description of free-form curved surfaces. Some examples of surface sketches using the surface structure curves are shown.

An approximation method for analyzing open queueing networks with nonpreemptive priority is presented. This method takes into account the variability of the arrival processes and service times for each node in the network, and hence a general class of non-Markovian models can be analyzed. The approximation procedure has following three steps: (1) the separation of the two-class priority network into two single-class networks, (2) the analysis of the flow rates and variability parameters of internal arrival processes for each class network, (3) calculation of traffic characteristics for each node in the single-class networks. For the first step, a two-parameter virtual server method is established, in which the arrival processes and service times are approximately characterized by the first and second moments. The second step is based on the decomposition method for single-class non-Markovian networks. At the third step, traffic characteristics for the entire networks are obtained by assuming that the nodes are independent. It is possible to quickly analyze large network models by this approach, because the procedure does not require iteration or a great amount of calculation. Numerical results are given and validated by exact and simulation results for a tandem network model and by simulatons for the basic component models of complex networks. Also, we apply our approximation method to an end-to-end delay analysis for a packet-switching network for voice and data. The results indicates that the accuracy of the approximation method is sufficient for practical use.

A new recognition method for partially occluded two dimensional objects is described in the present paper. Several vectors named PSVs, Partial Shape Vectors, are proposed as local features of an object and used for recognition. Two dimensional objects similar to a given model are extracted by this method. PSVs denote turning angles at an arbitrary point of the contour line of an object. In the recognition process, PSVs of each picture point in the given image are obtained and compared with PSVs of feature points which were set on the model. From coordinate values of the candidates for the feature points, objects similar to the model are extracted.

In this paper, we propose two parallel M/M/1 queueing systems with dynamic routing under a threshold-type scheduling. Arriving customer is sent to the buffer of the faster server as far as the difference of two queues does not exceed a threshold value, but it should be sent to the buffer of the slower server if and only if the difference of two queues exceeds a threshold value. It is shown that as the difference of the two service rates becomes large, the two parallel M/M/1 queueing systems with dynamic routing under the threshold-type scheduling can reduce the mean queueing time of costomers in the system compared to the conventional nonthreshold-type one. It is also found that as the asymmetry in the two service rates increases, the optimum threshold value which minimizes the mean queueing time should be large to reduce the number of queueing customer in the buffer of the slower server. On the other hand, as the traffic intensity becomes large, the optimum threshold value tends to be small in order to increase the total service rate.

The waveform moments are used for analyzing the various types of signal waves. The ordinary moments can't properly express the characteristics of the given signal sequence, because they are calculated with simple summation formulas of the original signal values and the positive and negative values may cancel each other. So we define the power moments which utilize the square of signal in order to prevent the above defect. Moreover, the cross moments which evaluate the product of signals are derived as more generalized definitions. The cross moments can evaluate not only the characteristics of signal power but also the relations between two signals. Further, we extend the cross moments to the blockwise cross moments and the multicross moments, and then derive the corresponding expressions in frequency domain. Finally, we illustrate the usefulness of the cross moments with some application examples.

A parallel FFT (Fast Fourier Transform) is actually executed on a clustered multiprocessor system with 32 processors to study real performance of three communication schemes, common memory, linear array and ring array. The speed-up of parallel FFT to a serial computer really depends on the number of data to be transformed and the number of processors. It is also proved that the performance really depends on the communication scheme of multiprocessor system.

A trial of statistical evaluation based on the probability distribution function is theoretically proposed in the actual case when a non-Gaussian type sound noise exhibits nonstationary properties due to a temporal change of statistical parameters. Next, when a nonstationary sound pressure wave of non-Gaussian type passes through a sound insulation system, the probability distribution of transmitted noise intensity is theoretically derived by reflecting the nonstationary properties of incident noise and the frequency characteristics (or impulse response) of the noise insulation system. The proposed evaluation method is employed for an aluminum single-wall whith nonstationary Gaussian type incident noise and compared with experimentally observed values. All results show good agreement with experimental results.

Osaka Gas has been investigating artificial intelligence for 6 years, focusing especially on research into ICAI. We have developed a simulation based GTS (Generic Training System) in cooperation with Vanderbilt University, in Tennessee USA. This system is one of the few practical ICAI systems used for real fields, and the coursewares can be developed without any programming skill. Topics covered in this paper include the system architecture, system modules and main features. As an example, a model-based intelligent tutoring system for power distribution training systems (PDTS) is also provided. The system is in use at several places in Osaka Gas.

Based on the MSN algorithm, an adaptive algorithm capable of controlling antenna patterns by phase weight only is derived. Then, an algorithm for phase nulling convenient in case not needing adaptive weight control is derived. This algorithm with null directions only being the parameter is convenient for pattern synthesis and pattern improvement. Finally, two examples are presented to demonstrate usefulness and validity of the technique.

The problems of robust tracking with stability for uncertain plants are considered. Uncertrain plants of one type are systems whose transfer matrices are only known to belong to a convex hull of prescribed transfer matrices P1, P2,, PN . Such uncertain systems include some dynamical interval systems as examples. A necessary and sufficient condition for the solvability is represented in terms of extreme points P1, P2,, PN of the convex hull. The solvability condition is testable and leads to a systematic procedure for designing a robust feedback control system.

The maximum power density of FM carrier modulated by a multi-channel telephony signal (Gaussian noise) with the approximated CCIR pre-emphasis characteristics is calculated by the summation of convolutions up to the 300th order. The results are shown in a figure as a function of m (rms modulation index) and e (ratio of minimum to maximum baseband frequencies) and are compared with approximations.

This paper describes the post-detection diversity improvement of a binary DPSK system in the fast Rician fading environment encountered in mobile satellite communication system. Firstly, the error probability is presented by a closed form which contains no special functions, then the optimum weighting factors in diversity branches to minimize the bit error rate (BER) are investigated. To minimize the BER, the maximum likelihood ratio detection principle is used for the detector outputs with exponential-type probability density function. Some unknown channel parameters contained in the optimum weighting factors are estimated by the channel estimators in diversity branches. Finally, the theoretical BER performances of three kinds of mobile satellite communication systems (satellite/aircraft, satellite/land mobile and satellite/ship) are presented.

We have already measured ground clutter using an X-band and L-band radars. Here, ground clutter was first measured using a millimeter wave radar with the frequency of 34.86 GHz, which is located on the campus of the University of Electro-Communications. The pulsewidth of the radar was 30 ns. Thus the spatial resolution was as small as 4.5 m. We have found that the clutter amplitude distribution obeys a Weibull distribution with shape parameter of c0.497 to 0.675 at depression angles of 0.8 to 1.9 deg., when reflectors are ordinary terrain and such structures as landing strips at airport and buildings. To improve target detectability in such Weibull-distributed ground clutter, Weibull constant false alarm rate (CFAR) system will be required.

A wideband loop antenna system has been tested using the sounding rocket S-310-18 to confirm its performance in detecting electromagnetic waves for frequencies from ELF to MF band in the lower ionosphere. The loop antenna system detected the one-hop whistlers with a high Signal-to-Noise ratio in 0.1-12 kHz, the spectra of which are used to study the propagation characteristics in the ionosphere. The VLF signal transmitted from the NDT station (Yosami, 17.40.05 kHz) was continuously received during the flight of rocket. The altitude dependence of the wave intensity and polarization are obtained. The polarization change of NDT signal from linear (free space mode) to circular (whistler mode) was clearly observed at a certain altitude in the ionosphere. The three Omega waves from Tsushima were detected and their height patterns of wave intensity are derived. A middle frequency radio wave (873 kHz) from Kumamoto Broadcasting Station was for the first time detected by the wideband loop antenna. It was found that the wave intensity decreases abruptly in the lower ionosphere due to absorption and reflection. This phenomenon was found to occur during both ascent and descent. Thus, it has been shown that the wideband loop antenna system tested in this rocket experiment has potential merit when applied in a space vehicle.

A set A is said to be invertibly paddable if there are two polynomial time computable functions pad and decode such that () xA if and only if pad (x, y) A, and () decode (pad (x, y)) y. We consider three number theoretical problems that are used in certain cryptosystems (decision of quadratic residuosity, computation of discrete logarithm and computation of Euler's totient function), and show that the sets that represent these problems are invertibly paddable. These results imply that, if these sets are not in P, then they have complexity cores C such that neither C not the complement of C are sparse.

Along with the advances in network digitalization and the development of new service capabilities, international telecommunication networks have been evolving toward ISDNs. The introduction of computer-controlled network operation techniques such as dynamic routing in the ISDN era will facilitate the highly efficient use of network resources with high reliabilities. In this paper, an international ISDN traffic profile model is introduced, and then a simple design method for international network using the dynamic routing of the pre-planned time-varying type is presented. A constraint concerning traffic survivability for robust network design is taken into account in the proposed method. The improvement of resource utilization and reliability performance attained by the introduction of the dynamic routing scheme is numerically evaluated based upon the design results for simplified models of international ISDNs.

Transition phenomena associated with synchronization are investigated between van der Pol and hard-mode oscillators with slightly different frequencies interacting through linear coupling. Three types transitions between asynchronous and synchronous states appear, and power law divergence of time describing the transition is observed near the transition point.

This paper deals with a popular puzzle known as Hi-Q. The puzzle is generalized: the board is extended to the size nn, an initial position of the puzzle is given, and a place is given on which only one token is finally placed. The complexity of the generalized Hi-Q is proved NP-complete.