基于云计算环境的医学信息集成

随着计算机设备在医学图像领域的大量应用和数字图像技术的快速发展,医学影像信息数据量急剧增长.如何有效地集成、管理和分析规模如此大的医学数据,仍是一大挑战.本文提出一种基于云计算技术的医学信息集成方法,将分布式数据存储和并行计算技术应用到医学信息集成中,用以实现离散的医学信息系统中各类异构医学数据信息的集成、共享、有效整合及应用.在此方法的基础上,构建了一个医学信息整合中心原型,并对集成方法的有效性进行了验证.     

A Novel Genetic Algorithm for the Design of a Signed Power-of-Two Coefficient Quadrature Mirror Filter Lattice Filter Bank

A novel genetic algorithm (GA) for the design of a canonical signed power-of-two (SPT) coefficient lattice structure quadrature mirror filter bank is presented in this paper. Genetic operations may render the SPT representation of a value noncanonical. In this paper, a new encoding scheme is introduced to encode the SPT values. In this new scheme, the canonical property of the SPT values is preserved under genetic operations. Additionally, two new features that drastically improve the performance of our GA are introduced. (1) An additional level of natural selection is introduced to simulate the effect of natural selection when sperm cells compete to fertilize an ovule; this dramatically improves the offspring survival rate. A conventional GA is analogous to intracytoplasmic sperm injection and has an extremely low offspring survival rate, resulting in very slow convergence. (2) The probability of mutation for each codon of a chromosome is weighted by the reciprocal of its effect. Because of these new features, the performance of our new GA outperforms conventional GAs.     

Low-temperature time-resolved photoluminescence in InGaN/GaN quantum wells

The results of the investigation of low-temperature time-resolved photoluminescence in undoped and Si-doped In_0.2Ga_0.8N/GaN structures, which contain 12 quantum wells of width 60 Å separated by barriers of width 60 Å, are reported. The structures were grown by the MOCVD technique on sapphire substrates. The photoluminescence properties observed are explained by the manifestation of two-dimensional donor-acceptor recombination. These properties are the high-energy shift of the peak upon increasing the pumping intensity, a low-energy shift with increasing delay time, and a power law of luminescence decay of the t ^-γ type. The estimates of the total binding energy for donor and acceptor centers are given. This energy is 340 and 250 meV for Si-doped and undoped quantum wells, respectively. The role of the mosaic structure, which is typical for Group III hexagonal nitrides, is discussed as a factor favorable for the formation of donor-acceptor pairs.     

Implementation of a third-generation 1.1-GHz 64-bit microprocessor

This third-generation 1.1-GHz 64-bit UltraSPARC microprocessor provides 1-MB on-chip level-2 cache, 4-Gb/s off chip memory bandwidth, and a new 200 MHz JBus interface that supports one to four processors. The 87.5-million transistor chip is implemented in a seven-layer-metal copper 0.13-/spl mu/m CMOS process and dissipates 53 W at 1.3 V and 1.1 GHz.     

Thermoelectric Properties of n-Mg2(SiGe)0.8Sn0.2 Solid Solution

Semiconductors - High values of the thermoelectric figure of merit (ZT = 1.5) in Mg2Si–Mg2Sn solid solutions are caused by a low thermal conductivity and a complex band structure, which is...     

Piecewise parabolic negative magnetoresistance of two-dimensional electron gas with triangular antidot lattice

Extraordinary piecewise parabolic behavior of the magnetoresistance has been experimentally detected in the two-dimensional electron gas with a dense triangular lattice of antidots, where commensurability magnetoresistance oscillations are suppressed. The magnetic field range of 0–0.6 T can be divided into three wide regions, in each of which the magnetoresistance is described by parabolic dependences with high accuracy (comparable to the experimental accuracy) and the transition regions between adjacent regions are much narrower than the regions themselves. In the region corresponding to the weakest magnetic fields, the parabolic behavior becomes almost linear. The observed behavior is reproducible as the electron gas density changes, which results in a change in the resistance by more than an order of magnitude. Possible physical mechanisms responsible for the observed behavior, including so-called “memory effects,” are discussed.     

GaAs–AlGaAs heterostructure thyristors with completely optical transfer of emitter current

Several variants of thyristors based on GaAs-AlGaAs heterostructures with optical transfer of the emitter current are considered. The possibility that thyristors with fully optical transfer of the emitter current can be, in principle, created is demonstrated by means of the results of a study of n-p-n and p-n-p optoelectronic transistors in which the emitter current is converted into light, this light, in turn, being converted into a collector current. Structures of optoelectronic switches of this kind are presented. A switch comprising three constituent transistors has been suggested and fabricated taking into account specific features of the technique for growth of undoped GaAs layers and fabrication of high-voltage p ⁰-n ⁰ junctions with back-ground impurities from these layers, which makes the turn-on delay cardinally shorter and raises the working frequency.     

AC-PDP发光物理过程及影响发光效率、亮度因素的探讨

分析了彩电ＡＣ－ＰＤＰ平面显示结构原理,着重讨论了其物理发光过程,并提出进一步提高ＡＣ－ＰＤＰ发光效率和亮度的途径。     

Delay-dependent fault detection for switched linear systems with time-varying delays—the average dwell time approach

In this paper, the fault detection problem is investigated for a class of discrete-time switched linear systems with time-varying delays. The main purpose is to design a fault detection filter such that, for all unknown inputs, control inputs and time delays, the estimation error between the residual and fault is minimized in an exponential way. The fault detection problem is converted into an exponential H_∞ filtering problem. By using a newly constructed Lyapunov functional and the average dwell time scheme, a novel delay-dependent sufficient condition for the solvability of this problem is established in terms of linear matrix inequalities (LMIs). A numerical example is given to demonstrate the effectiveness of the developed theoretical results.     

门诊草药管理的探讨

草药管理是中医院管理中的难题,解决好草药管理是中医院信息建设的前提。