This paper introduces recent concept on the optical system of compound eyes. Among the compound eyes, superposition eye whose image forming principle is comming to clear recently is especially taken into consideration: morphological characteristics, refractive index distribution of dioptric system, image forming principle derived by ray tracing method, and optical characteristics of rhabdom based on light guide theory are introduced.
Advances of these years in field of speech analysis, synthesis, and recognition are briefly reviewed. First, engineering model of speech production is introduced as a time varying linear system drived by impulse train (voiced sound) or white noise (unvoiced sound). Some surveys are given on some important methods for speech analysis-synthesis such as linear predictive coding (LPC) and partial autocorrelation (PARCOR) as well as the most recent advances: line spectrum pairs (LSP) and composite sinusoid modeling (CSM). These are also fundamental techniques for narrow band speech transmission and efficient storage of speech. Speech synthesis techniques including speech wave compilation, parameter compilation, and synthesis by rule are discussed. Last, some varieties of speech recognition, that is, isolated word recognition, continuous speech recognition, and talker recognition are reviewed.
Progress in optical fiber communication is reviewed with emphasis on low loss and broadband fibers and transmission system characterization. Field evaluation at the 0.85μm wavelength for public telecommunication, power system supervision and control and local television broadcasting have proven to be successful. Superior performance is expected in fiber systems with long wavelength carriers toward long repeater span and high data rate performance.
Physical and technological limits in size of semiconductor devices are discussed from the viewpoints of statistical fluctuation of total number of impurities in devices as a physical limit and statistical fluctuation of size of devices, dependence of device characteristics on the size of the device, power dissipation, electromigration and α particle induced effect as technological limits. Statistical fluctuation of total number of impurities indicates rather large size as a minimum dimension. As for lithography electron beam has a good capability, but backscattering of electrons limits the accuracy and precision of patterns. Therefore electron resist with high contrast should be developed. Scaling down of devices normally leads to the improvement of high frequency characteristics, but the low breakdown voltage is resulted. Limit by heat dissipation is serious. These technological limitations indicate that devices whose size is about 1μm as a dimension are of the minimum size.
Recent progress in the fields of devices for optical communications is briefly reviewed, laying stress on the progress of optical fibers, optical semiconductor devices and optical circuit components. The main features are realization of high performance devices such as ultra-low loss optical fibers and single mode semiconductor lasers, movement toward longer wavelength regions and advancement of techniques relating to single modefiber utilization.
The performance of linear and area image sensors, which employ charge coupled device concept, has been greatly improved in the last few years. The linear image sensor has widely been used as practical devices in many systems such as facsimile transmitters and optical character readers. The area image sensor is now beginning of practical use. The device structure, operation method and performance of the linear and area sensors are described. Great many types of infra-red image sensor, which make use of time delay and integration on the focal plane array, have recently been developed in monolithic and hybrid fashion by the aid of the charge coupled device technology. Recent progresses in this field are reviewed.
In this paper present status and future development of bubble memory device will be presented from a viewpoint of its practical use. In order to improve the cost performance of bubble memory, it is necessary to achieve a higher bit density chip with decrease of production cost. Conventional permalloy devices can have chip bit densities of up to about 1M bits/cm2 with low production cost. However for higher bit densities, for example, greater than 4M bits/cm2, it is believed that new device concept must be introduced. The ion implanted devices, the wall coding devices and the Bobeck current access device have been developed for producing higher bit density chip. At present it seems that the ion implanted devices are the most promising among them and will yield chip with densities of up to about 10M bits/cm2. Achievement of such a high bit density gives promise of bright future for bubble memory.
A review on the present status of data handling and related data acquisition systems used in high energy particle physics experiments, is made. In particular, recent developments in on-line data processing using mini-computers and microcomputers are discussed. A brief comment is made on a prospect of future developments.
It is represented from a view point of a solid state physicist how the solid state physics has been used in the field of information processing and transmission. Firstly we study what kind of physical properties are used in electronic circuits of parametron and Esaki diode. Dream for optical computer arises naturally when the optical communication is being used in practice due to development of semiconductor laser and optical fibers. We survey present status of the optical information processing and transmission.
In recent years, computer and associated software technology has become of increasing importance in any spectroscopy laboratory. A variety of computer techniques are being applied not only to numerical analyses of spectra but also to automatic data collection for releasing the spectroscopist from tedious and time-consuming work. However, it should be noted that the computer also demonstrates its tremendous power in increasing the reliability of data which will be endurable for further analysis. This article presents the current status on computer applications particularly to numerical data handling for accomplishing reliable spectroscopic measurements, which covers main categories of waveform processing such as Fourier transformation, digital filtering, deconvolution and curve decomposition.