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151.
The behavioral approach to system theory provides a parameter-free framework for the study of the general problem of linear exact modeling and recursive modeling. The authors present the solution of the (continuous-time) polynomial-exponential time series modeling problem. Both recursive and nonrecursive solutions are provided and classified according to properties like complexity and controllability. It is shown, in particular, that recursive modeling corresponds to updating by means of a cascade inter-connection of systems. As a special case, the solution of several other problems, such as rational interpolation, realization, and modeling of arbitrary discrete-time time series, is obtained  相似文献   
152.
Summary The synthesis of new high optical abrasion resistance coating materials has been undertaken by functionalizing melamine and tris(m-aminophenyl)phosphine oxide with a triethoxysilane containing reagent. These highly functionalized compounds have been used for coating a bis-phenol-A polycarbonate substrate by the sol-gel method. Preliminary data shows the abrasion resistance of the polymer substrate is considerably improved when it is coated by these optically clear materials.  相似文献   
153.
Many current implementations of protocols such as the Transmission Control Protocol/Internet Protocol (TCP/IP) are inefficient because data are often accessed more frequently than necessary. Three techniques that reduce the need for memory bandwidth are proposed. The techniques are copy-on-write, page remapping, and single-copy. Afterburner, a network-independent card that provides the services that are necessary for a single-copy protocol stack, is described. The card has 1 MByte of local buffers and provides a simple interface to a variety of network link adapters, including HIPPI and asynchronous transfer mode (ATM). Afterburner can support transfers to and from the link adapter card at rates up to 1 Gbit/s. An implementation of TCP/IP that uses the features provided by Afterburner to reduce the movement of data to a single copy is discussed. Measurements of the end-to-end performance of Afterburner and the single-copy implementation of TCP/IP are presented  相似文献   
154.
The effect of long-term feeding (252 days) of three supplemental levels of α-tocopheryl acetate (actual 0, 360 and 1290 IU/head/day) on meat quality was evaluated in Holstein and beef breed steers. Tissue vitamin E concentrations were increased by each increment of supplementation. The color display life of fresh beef under simulated retail conditions was extended 2 to 5 days by vitamin E and lipid oxidation was markedly reduced. Microbial population was not affected by level of supplementation. No deterioration in sensory quality occurred for steaks from supplemented steers that were displayed until the time steaks from unsupplemented steers discolored.  相似文献   
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157.
The Inc A/C plasmids, like Inc P and Inc Q plasmids, have a broad host range. However, their maintenance functions remain to be studied. An autoreplicative region of 2.79 kb named RepA/C, able to replicate both in the family Enterobacteriaceae and in Pseudomonas spp., was isolated and sequenced. The stability, copy number, and incompatibility expression of this replicon were determined. RepA/C and a nonautoreplicative fragment of 16 kb of this replicon were used as probes and showed specific hybridizations with the Inc P3-A/C plasmids from Pseudomonas spp. and members of the Enterobacteriaceae. These probes could be used as tools for identification of the plasmids of this epidemiologically important Inc group.  相似文献   
158.
Cardiac papillary fibroelastomas are unusual, frond-like growths typically found on cardiac valves, diagnosed incidentally on autopsy or cardiac surgery, but rarely during life. We report a rare case of an aortic valve papillary fibroelastoma detected by transthoracic echocardiography and confirmed by histologic study.  相似文献   
159.
We present methods to generate rendering sequences for triangle meshes which preserve mesh locality as much as possible. This is useful for maximizing vertex reuse when rendering the mesh using a FIFO vertex buffer, such as those available in modern 3D graphics hardware. The sequences are universal in the sense that they perform well for all sizes of vertex buffers, and generalize to progressive meshes. This has been verified experimentally.  相似文献   
160.
This paper analyzes probability of bit-error (Pe) performance of asynchronous bandlimited direct-sequence code-division multiple-access systems with binary phase-shift keying spreading. The two present methods of Pe analysis under bandwidth-efficient pulse shaping: the often-cited standard Gaussian approximation and the characteristic function (CF) method suffer from either a low accuracy in regions of low Pe (< 10-3) or a prohibitively large computational complexity. The paper presents an alternate method of Pe analysis with moderate computational complexity and high accuracy based on a key observation. A sequence of chip decision statistics (whose sum yields a bit statistic) forms a stationary, m-dependent sequence when conditioned on the chip delay and phase offset of each interfering signal. This observation permits the generalization of the improved Gaussian approximation previously derived for the rectangular pulse and the derivation of a numerically efficient approximation based on the CF method. Numerical examples of systems using the square-root raised-cosine and IS-95 pulses illustrate THE P e performance, user capacity and the accuracy of the proposed method  相似文献   
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