It is well known that extracting parallel loops plays a significant role in designing parallelizing compilers. The execution efficiency of a loop is enhanced when the loop can be executed in parallel or partial parallel, like a DOALL or DOACROSS loop. This paper reports on the practical parallelism detector (PPD) that is implemented in PFPC (a portable FORTRAN parallelizing compiler running on OSF/1) at NCTU to concentrate on finding the parallelism available in loops. The PPD can extract the potential DOALL and DOACROSS loops in a program by invoking a combination of the ZIV test and the I test for verifying array subscripts. Furthermore, if DOACROSS loops are available, an optimization of synchronization statement is made. Experimental results show that PPD is more reliable and accurate than previous approaches.

A high efficiency and low voltage operation GaAs power amplifier module has been developed for the application to 1.5 GHz Japanese digital cellular phones. This paper summarizes the design method to increase efficiency and to reduce adjacent channel leakage power. Operated at a low drain bias voltage of 4.6 V, the power amplifier module delivers an output power of 1.5 W with 46% power-added efficiency and -52 dBs adjacent channel leakage power.

The analytic structure of the governing equation for a 2nd order Phase–Locked Loops (PLL) is studied in the complex time plane. By a local reduction of the PLL equation to the Ricatti equation, the PLL equation is analytically shown to have singularities which form a fractal structure in the complex time plane. Such a fractal structure of complex time singularities is known to be characteristic for nonintegrable, especially chaotic systems. On the other hand, a direct numerical detection of the complex time singularities is performed to verify the fractal structure. The numerical results show the reality of complex time singularities and the fractal structure of singularities on a curve.

As a result of examination based on a newly available data set of millimeter-wave rain attenuation measured in the UK, it is found that the ITU-R specific rain attenuation model tends to appreciably underestimate millimeter-wave rain attenuation at frequencies above about 60GHz for the UK rain climate. This tendency is very similar to that previously reported for the Japanese experimental data at frequencies up to 245GHz. Furthermore, an alternative specific rain attenuation model based on the Japanese experimental data is found to be in fairly good agreement with the experimental data in the UK at frequencies up to 137GHz.

Optical WDM (Wavelength Division Multiplexing) technology is a method of exploiting the huge bandwidth of optical fibers. Local lightwave networks which use fixed wavelength transmitters and receivers can be built in a multihop fashion. In multihop local lightwave networks, packets arrive at their destination by hopping a number of intermediate nodes. The channel sharing schemes for multihop lightwave networks have been proposed for efficient channel utilization, but those schemes result in the degradation of network capacity and the user throughput. In this paper, we propose an improved WDM channel sharing scheme using the logically bidirectional perfect shuffle interconnection pattern, achieving smaller number of average hops for transmission and better channel utilization efficiency. Better channel utilization efficiency is obtained without much deteriorating the network capacity and the user throughput. TDMA (Time Division Multiple Access) protocol can be used to control the sharing of channels, and time delay and lost packet probability analysis based on TDMA is performed.

We analyze the nonlinear dynamics of PLL from the "complex" singularity structure by introducing the complex time. The most important results which we have obtained in this work are as follow: (1) From the psi-series expansion of the solution, the local behavior in the neighbourhood of a movable singularity is mapped onto an integrable differential equation: the Ricatti equation. (2) From the movable pole of the Ricatti equation, a set of infinitly clustered singularities about a movable singularity is shown to exist for the equation of PLL by the multivalued mapping. The above results are interesting because the clustering and/or the fractal distribution of singularities is known to be a characteristic feature of the non-integrability or chaos. By using the method in this letter, we can present a circumstantial evidence for chaotic dynamics without assuming any small parameters in the equation of PLL.

In this paper, a general theory on multiple-valued static random-access-memory (RAM) is investigated. A criterion for a stable and an unstable modes is proved with a strict mathematical method and expressed with a diagrammatic representation. Based on the theory, an NMOS 6-transistor ternary and a quaternary static RAM (SRAM) cells are proposed and simulated with PSPICE. The detail circuit design and realization are analyzed. A 10-valued CMOS current-mode static RAM cell is also presented and fabricated with standard 5-µm CMOS technology. A family of multiple-valued flip-flops is presented and they show to have desirable properties for use in multiple-valued sequential circuits. Both PSPICE simulations and experiments indicate that the general theory presented are very useful and effective tools in the optimum design and circuit realization of multiple-valued static RAMs and flip-flops.