Mitsubishi

About: Mitsubishi is a company organization based out in Tokyo, Japan. It is known for research contribution in the topics: Layer (electronics) & Signal. The organization has 53115 authors who have published 54821 publications receiving 870150 citations. The organization is also known as: Mitsubishi Group of Companies & Mitsubishi Companies.

Burst erasure correction codes with low decoding delay

Abstract: We present a new class of systematic, time-invariant, convolutional encoders suitable for low delay burst erasure correction. Specifically, we show that the new encoders have the shortest possible decoding delay required to correct all bursts of a given length with a fixed redundancy. By comparing the new encoders to maximum distance separable (MDS) codes, we show that the latter generally require either more redundancy or more delay to correct bursts of a given length. In addition, we show that the new encoders can achieve better performance than MDS codes on a simple two-state Markov erasure channel. Thus, we demonstrate the advantages of using cross packet coding for delay-sensitive applications such as Voice over Internet Protocol, video-conferencing, etc., on bursty packet networks. Finally, we discuss suitable performance measures for encoders designed to correct both burst and random erasures and report the results of a computer search for such hybrid encoders.

Expression of Foxp2, a gene involved in speech and language, in the developing and adult striatum.

Abstract: Many members of the forkhead/winged helix transcriptional factors are known to be regulators of embryogenesis. Mutations of the Fox gene family have been implicated in a range of human developmental disorders. Foxp2, a member of the Fox gene family, has recently been identified as the first gene that is linked to an inherited form of language and speech disorder. To elucidate the anatomical basis of language processing in the brain, we have examined the expression pattern of Foxp2 gene and its homologous gene, Foxp1, in the rat brain through development. Expression of Foxp2 mRNA was detected in the ventral telencephalon as early as embryonic day 13. Foxp2 mRNA was expressed primarily in differentiated cells of the lateral ganglionic eminence (striatal primordium). Of particular interest was that the developmental expression of Foxp2 followed a compartmetnal order in the striatum. Patches containing high levels of Foxp2 were aligned with patches enriched in mu-opoid receptor, a marker for striosomal cells, in the striatum through postnatal development. Conversely, Foxp2-positive patches were devoid of calbindin-D28k, a maker for striatal matrix cells. Therefore, Foxp2 was preferentially expressed in striosomal compartment in the striatum during development. In the mature striatum, Foxp2 expression was maintained in striosomes, although its expression level was reduced. In contrast to Foxp2, Foxp1 was expressed in both the striosomal and matrix compartments in the striatum through development. The striatum is known to be involved in the process of procedural memory, and mutation of Foxp2 results in neurological disorders of language and speech. Given the preferential expression of Foxp2 in the striosomal compartment, the striatum, particularly the striosomal system, may participate in neural information processing for language and speech. Our suggestion is consistent with the declarative/procedural model proposed by Ullman and colleagues (Ullman et al. [1997] J. Cogn. Neurosci. 9:266–276; Ullman [2001] Nat. Rev. Neurosci. 2:717–726), in which the procedural memory-dependent mental grammar is rooted in the basal ganglia and the frontal cortex and the declarative memory-dependent mental lexicon is rooted in the temporal lobe. © 2003 Wiley-Liss, Inc.

Substrate holder for MOCVD

Abstract: A substrate holder employed for MOCVD and supporting a wafer on which crystal growth proceeds includes a molybdenum holder body, a GaAs polycrystalline film with a flat surface grown on a part of the surface of the molybdenum holder body where the wafer is absent, and an InP polycrystalline film grown on the GaAs polycrystalline film. Each of the polycrystalline films is grown to a thickness of 0.3 μm or more at a temperature higher than the epitaxial growth temperature of 575° C. During the MOCVD process, the emissivity of the molybdenum substrate holder is stable at a value near the emissivity of the wafer on the substrate holder and, therefore, the decomposition ratio of PH3 gas on the substrate holder is stable at a value near the decomposition ratio on the wafer, whereby any variation of the incorporation ratio of P atoms in the grown InGaAsP, i.e., a variation of the composition of the InGaAsP, is reduced and run-to-run variations of the composition of the grown crystal are reduced.