摘要:

AbstractThis paper proposes a permanent time‐stamp ordering mechanism as a concurrency control mechanism in the distributed database, where transactions are served in the order of their arrivals. In the proposed mechanism, the read time stamp and the write time stamp are recorded on each data item; and when a conflict arises between transaction services, the transaction with a larger time stamp is aborted. This paper describes the algorithm for the permanent time‐stamp ordering mechanism and confirms the validity of the algori

ISSN:0882-1666    

DOI:10.1002/scj.4690230901

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractPrevious research on information security has focused on the protection of the contents of messages. But in many cases it is equally important to protect the identities of the sender and receiver and also the time of message transmission.This paper proposes communication protocols which make it impossible both for the entities other than the right receiver to decipher the message and for any third party to identify the communicating entities. Since it is impossible in these protocols for any third party to identify the communicators, the protocols are classified into four groups according to whether or not the communicating pair can identify each other. In addition, the security, the implementability, and the mutual relationship of these four kinds of communication protocols are studied.

ISSN:0882-1666    

DOI:10.1002/scj.4690230902

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper discusses the optical telemetry system for a life science experiment conducted in a space station, the feature of which is the telemetry of multichannel biosignals from a number of objects in the same booth.First, the enforced synchronization telemetry system is proposed. This system is based on two‐way communication which forms the key to the simultaneous biosignal telemetry from a number of objects. Based on the proposal, an experimental system is constructed. The external system sends a command signal to the object side and then receives and demodulates the telemetry signal from the object side. This system was implemented on a breadboard.The control unit for the multiplex telemetry system attached to the biological object is designed and constructed using dedicated BiCMOS. In this unit, approximately 400 elements are integrated into a 3.6 × 4.6 mm2chip, realizing the function to telemeter four channel signals from up to four objects with the sampling frequency of 1 kHz.A series of operations was verified as satisfactory. Then include the reception of the optical command signal, selection of the object, multiplexing of a number of biosignals, and the transmission of telemetry signals. Using the experimental telemetry system based on the enforced synchronization, the operation of the parallel telemetry is verified as a principle for the two‐channel biosignals from two objects. The result is evalu

ISSN:0882-1666    

DOI:10.1002/scj.4690230903

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe electroretinogram (ERG) is considered interesting not only as a diagnostic information in the ophthalmological clinics but also in biological engineering as a clue to the opto‐electric conversion mechanism in the retina. Conventionally, ERG is observed using the whole field stimulation of the retina by a strong flash, where the information concerning the local activities of the retina cannot be obtained. Another point in ERG is that the analysis is difficult due to the nonlinearity and the ambiguity of the stimulus waveform. This paper proposes a new method which analyzes the frequency characteristics of the micro‐ERG (μ‐ERG), evoked by the stimulation using the light‐emitting diode (LED).This method has the following advantages: the stimulating waveform can be controlled arbitrarily; the method of linear system analysis can be applied; the local stimulation can be realized; and the color sensation can be examined.This paper discusses two basic techniques in the detection of the μ‐ERG. One is the Fourier analysis of the synchronized ERG evoked by the sine wave stimulus, and the other is the correlation analysis using the random stimulus. The results of the two methods are compared, and the usefulness of the proposed method i

ISSN:0882-1666    

DOI:10.1002/scj.4690230904

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractA system to detect eye direction via image processing is being studied for a better human‐machine interface. It is important in this method that feature points relating to an eye be extracted stably.This paper proposes the design of an optical system which efficiently extracts the image of a pupil as a feature point from its background. The image of a pupil can clearly be recorded by a camera by illuminating the eye with an infrared ray which is reflected from the fundus of the eye and exits through the pupil. However, the distribution of the brightness of the pupil image varies widely depending on the relative position of the ray sources.To analyze these conditions, an eye model consisting of a transparent double‐sphere is introduced. Using this model and a ray‐tracing method, the conditions of the illumination to provide an even image of the entire pupil have been obtained. The result shows that the ray sources should be arranged symmetrically within a specific radius of the optical axis of the camera lens. The calculation based on these conditions agrees with the experimental results, showing the effectiveness of this simulation.The conditions to make the image of a pupil dark have also been obtained by applying the same method. To emphasize the contrast of the image of a pupil against its background, a method using a single camera and two ray sources having different conditions is proposed; the camera produces a set of two images of a pupil (bright and dark), and then the difference of the images is simply digi

ISSN:0882-1666    

DOI:10.1002/scj.4690230905

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractWhen observing an overlapped figure, a human tends to interpret the figure by decomposing it into simpler subfigures. In psychology, this attitude is called figure segregation. In general, an overlapped figure can be segregated in many ways, depending on the observer. In the engineering realization of the figure segregation, the frequency of selection for each segregation candidate must be estimated.Up to now, such factors as symmetry and continuity have been considered qualitatively as the factors affecting the decision about the segregation of the figure. This paper presents first a method to describe quantitatively those factors. Then the significance of the decision factor is determined by comparing the characteristic values of the decision factor in the segregation candidate and the selection frequency of that candidate in the psychological experiment. Furthermore, it is shown that the figure segregation characteristics can be estimated accurately, based on the prediction expression derived from the linear multiple regression analysis.

ISSN:0882-1666    

DOI:10.1002/scj.4690230906

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractIn image synthesis, extraction methods to extract meaningful regions (simple meanings) such aspeopleorflowersfrom ordinary natural images are important. Although the chroma‐key method is widely used to extract these meaningful regions, it requires a blue background, a special photographic environment, and cannot be applied to natural images. Video‐matte, which extracts objects assisted by the user, has been developed and put to practical use as a method applicable to natural images. In this method, however, the region's boundary must be accurately specified in units of picture elements (pixels) and demands a great deal of effort and skill.In this paper, we propose a new method that simplifies the task of specifying the region in video‐matte. The user only has to specify the object to be extracted, which is easily done; then the actual region extraction is performed automatically by image processing techniques. In addition, a new thinning method for obtaining precise boundaries is also proposed. This method has many practical features: applicability to any natural image, simple specification of the boundary, a one‐pixel wide boundary with no branches or breaks, and no par

ISSN:0882-1666    

DOI:10.1002/scj.4690230907

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractTemplate matching is a useful technique for matching images. This paper proposes a high‐speed template matching technique which is effective for images that have sharp contours. The method uses only the image contour parts as one‐dimensional templates. Although it can retain fine patterns, the data compression ratio and speed are very high. To improve reliability of matching, gray gradient information and intensity of contour points are used. Also, dilation of contours can reduce several errors due to disturbance of the contour or scaling. The algorithm herein can indicate differences between the template and the target image automatically after the alignment of images.The expanded algorithm applying the sequential similarity detection algorithm (SSDA) method also is discussed. Software simulation proved that the algorithm is 10 or 200 times faster than the conventional template matching technique which uses the cross‐correlation estimation between two‐dimensional (2‐D) template and the target image. This algorithm was applied to special hardware. It can align two 512 × 512 pixels images in 40 ms when the size of the search area

ISSN:0882-1666    

DOI:10.1002/scj.4690230908

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractAssembly illustrations are drawn usually in an assembly manual to show assembly information because, in many cases, instructions cannot show assembly information unambiguously enough. Therefore, it is necessary to combine the assembly information both from instructions and illustrations so that unambiguous assembly information is obtained finally. Naturally, it becomes necessary to construct a cooperative system for image understanding and language understanding. For such a final purpose, the purpose of this study is to obtain assembly information only from illustrations by means of image understanding.This paper presents an approach for obtaining assembly information from illustrations. As an example, the approach takes an auxiliary line employed to show an assembly relation between two certain mechanical parts. By extracting auxiliary lines and using the information on the location and orientation of these lines, we can recognize not only the assembly relations but also the structure of mechanical parts, especially such structural details as the invisible or occluded holes. Further, the assembly order can also be conjectured to some extent from an illustration in which several assembly relations are shown simultaneously. By taking advantage of the foregoing information, the system can decide whether an object is equal to the assembly constructed from the given illustration.

ISSN:0882-1666    

DOI:10.1002/scj.4690230909

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY