Coding of computer generated (CG) images with visually acceptable quality is studied based on the lossless/near-lossless coding methods defined in the JPEG-LS standard, including their modification. First, a color transform into YCbCr is done and its lossless coding is found to reduce the lossless coding in RGB space by 20-53%. As the normal JPEG-LS near-lossless coding methods are found not to provide acceptable image quality, another compatible method to JPEG-LS is proposed and found to reduce the bit-rate of lossless coding by about 20-30%, while keeping almost acceptable picture quality. Finally, we propose a new method that can achieve a reduction of bit-rate from YCbCr lossless coding by 22-44%, keeping acceptable image quality for both. natural and CG images, though not compatible to JPEG-LS.

Proposes a scheme to realize a high-performance communication facility using a commodity network. This scheme does not require any special hardware or hardware-specific device drivers in order to adapt to many kinds of network interface cards (NICs). In this scheme, a reliable lightweight network protocol is handled directly on a data link layer called by a network device driver. An interrupt reaping technique is proposed to eliminate the hardware interrupt overhead when an application waits for a message. PM/Ethernet, an instance of the scheme, is implemented on Linux with minimal modification to the Linux kernel, and existing network device drivers are used without any modification. Using Pentium III 500-MHz PCs on Packet Engine's G-NIC II Gigabit Ethernet NIC, it achieves 77.5 MB/s bandwidth and 37.6 /spl mu/s round-trip time latency compared to that of TCP/IP, which achieves 46.7 MB/s bandwidth and 89.6 /spl mu/s round-trip time latency. The NAS parallel benchmark IS results show that MPI on PM/Ethernet achieves 75% better performance than MPI on TCP/IP and is 7.8% slower than that of MPI on Myrinet PM.

This paper introduces a high performance communication middle layer, called PM2, for hetero-geneous network environments. PM2 currently supports Myrinet, Ethernet, and SMP. Binary code written in PM2 or written in a communication library, such as MPICH-SCore on top of PM2, may run on any combination of those networks without re-compilation. According to a set of NAS parallel benchmark results, MPICH-SCore performance is better than dedicated communication libraries such as MPICH-BIP/SMP and MPICH-GM when running some benchmark programs.

A high performance communication facility, called the GigaE PM, has been designed and implemented for parallel applications on clusters of computers using a Gigabit Ethernet. The GigaE PM provides not only a reliable high bandwidth and low latency communication function, but also supports existing network protocols such as TCP/IP. In the design of the GigaE PM, it is assumed that the Gigabit Ethernet card used has a dedicated processor and its program can be modied. A reliable communication mechanism for a parallel application is implemented on the rmware while existing network protocols are handled by an operating system kernel. A prototype system has been implemented using an Essential Communications Gigabit Ethernet card. The performance results show that a 48.3 s round trip time for a four byte user message, and 56.7 MBytes/sec bandwidth for a 1,468 byte message have been achieved on Intel Pentium II 400 MHz PCs. We have implemented MPICH-PM on top of the GigaE PM, and evaluat...

An adaptive array antenna is effective for correcting degradation due to multipath interference in mobile communication systems. In a beam space adaptive array antenna, the weights of the component beams are optimized. Thus the main beam directions and the optimum weights of the component beams are known factors in transmitting. We propose a method for null-beam forming at the transmitting frequency that uses these parameters, which makes it possible to carry out adaptive null-beam forming both in receiving and transmitting.>