复用技术在光通信中的应用

用于扩容的光复用技术有三种,即光时分复用(OTDM)、光波分复用(OWDM)和正处于研究阶段的光码分复用(OCDMA)。WDM是指从光域上用波长复用方式来改进传输,提高复用效率。OTDM是指利用高速光开关把多路光信号复用到一路上传输。利用WDM现有特殊的优势,以及OTDM更具特点的组网方式,可为未来的全光网络提供更为灵活的网络解决方案。近年来,OCD-MA已经成为一项备受瞩目的热门技术,OCDMA为网络的发展提供了一条新的途径,OCDMA不仅可增加现有光纤设备的利用率,而且可大大减少待建光纤的数量。为了提高通信系统的性能价格比,满足迅猛发展的Internet业务的需要,迫切需要提高通信系统的带宽,这使得IP与光网络的结合成为必然的发展趋势,IP over-SDH,IP overATM,IP over WDM已成为研究和发展的重点。随着复用技术的发展,IP over OTDM和IPover OCDMA正逐渐浮出水面。为缓解通信网络的拥挤状况,增加网络的灵活性及适应数据业务的需要,美国和欧洲在某些地区的城域网中已采用了WDM技术。为实现城域网,可采用OTDM分组网络,光的分组交换城域网将是城域网的一个发展方向。利用OCDMA抗干扰能力强、保密性好,实现多址连接灵活方便和可直接进行光的编/解码的优点,不仅可以充分利用光纤信道带宽的潜力,而且可以比较容易地实现OVP     

Improved multiplex control systems: dynamic reliability and stochastic optimality

Redundant control systems are considered in the modelling context of stochastic jump linear processes. Optimal control problems are formulated for a quadratic performance index and solved for different classes of feedback laws and on-line information structures. The resulting control algorithms provide stochastic optimality together with dynamic reliability, thus improving previous conservative solutions based on a notion of stochastic stability     

对加壳技术的改进:超粒度混杂技术

首先介绍过去的一些软件保护技术,分析它们的不足之处,然后介绍目前应用最广泛的加壳技术和它的弱点。最后提出了改进的方法：超粒度混杂技术的原理、算法和具体的实现。     

SERS driven cross-platform based multiplex pathogen detection

We demonstrate a cross-platform approach to simultaneously detect three different pathogens using Raman and UV-vis absorption spectroscopy. Gold (Au), silver (Ag), and Ag-Au core-shell nanoparticles were functionalized with anti-Salmonella typhimurium aptamers, anti-Staphylococcus aureus and anti-Escherichia coli O157:H7 antibodies respectively and labeled with unique Raman reporter molecules. A microfiltration step was used to consolidate a highly selective and specific detection platform, with total detection time under 45 min for both species (E. coli O157:H7 vs. S. typhimurium) and strain (E. coli O157:H7 vs. E. coli K12) level sensing at a limit of a detection ranging between 10² and 10³ CFU/ml. This simple yet robust multiplex detection platform has the potential to be developed into a rapid and portable pathogen sensor for ultrasensitive detection in liquid samples.     

GPS: location-tracking technology

Increasing commercial use of the Global Positioning System will soon make it possible to locate anything, anywhere, anytime. The Global Positioning System can provide extremely accurate location information for mobile objects and people which is far superior to earlier tracking techniques. The challenge today is integrating the necessary components into older systems and improving GPS accuracy in areas with numerous obstructions. As more devices become GPS enabled, accuracy will increase and the system's scale and global reach will benefit everyone. Wireless technology promises to be a key element in any long-term solution     

A novel multiplex cascade classifier for pedestrian detection

Reliable pedestrian detection is of great importance in visual surveillance. In this paper, we propose a novel multiplex classifier model, which is composed of two multiplex cascades parts: Haar-like cascade classifier and shapelet cascade classifier. The Haar-like cascade classifier filters out most of irrelevant image background, while the shapelet cascade classifier detects intensively head-shoulder features. The weighted linear regression model is introduced to train its weak classifiers. We also introduce a structure table to label the foreground pixels by means of background differences. The experimental results illustrate that our classifier model provides satisfying detection accuracy. In particular, our detection approach can also perform well for low resolution and relatively complicated backgrounds.     

Characterizing and extracting multiplex patterns in complex networks

Complex network theory provides a means for modeling and analyzing complex systems that consist of multiple and interdependent components. Among the studies on complex networks, structural analysis is of fundamental importance as it presents a natural route to understanding the dynamics, as well as to synthesizing or optimizing the functions, of networks. A wide spectrum of structural patterns of networks has been reported in the past decade, such as communities, multipartites, bipartite, hubs, authorities, outliers, and bow ties, among others. In this paper, we are interested in tackling the challenging task of characterizing and extracting multiplex patterns (multiple patterns as mentioned previously coexisting in the same networks in a complicated manner), which so far has not been explicitly and adequately addressed in the literature. Our work shows that such multiplex patterns can be well characterized as well as effectively extracted by means of a granular stochastic blockmodel, together with a set of related algorithms proposed here based on some machine learning and statistical inference ideas. These models and algorithms enable us to further explore complex networks from a novel perspective.     

Performance analysis of an integrated hybrid-switched multiplex structure

The performance of an integrated voice/data hybrid-switched multiplex structure is analyzed. The approach is based on an imbedded two-dimensional Markov chain associated with the voice and data queueing processes, which accounts for their interaction. Using generating functions, a method for determining exactly the average data delay is given. As an application, an analytical expression for the average data delay is derived for the so-called single channel case. These results should be considered primarily as a theoretical contribution since the numerical difficulties involved in the solution procedure for the general case are formidable.     

ELISA: An estimated load information scheduling algorithm for distributed computing systems

In this paper, we present a decentralized dynamic load scheduling/balancing algorithm called ELISA (Estimated Load Information Scheduling Algorithm) for general purpose distributed computing systems. ELISA uses estimated state information based upon periodic exchange of exact state information between neighbouring nodes to perform load scheduling. The primary objective of the algorithm is to cut down on the communication and load transfer overheads by minimizing the frequency of status exchange and by restricting the load transfer and status exchange within the buddy set of a processor. It is shown that the resulting algorithm performs almost as well as a perfect information algorithm and is superior to other load balancing schemes based on the random sharing and Ni-Hwang algorithms. A sensitivity analysis to study the effect of various design parameters on the effectiveness of load balancing is also carried out. Finally, the algorithm's performance is tested on large dimensional hypercubes in the presence of time-varying load arrival process and is shown to perform well in comparison to other algorithms. This makes ELISA a viable and implementable load balancing algorithm for use in general purpose distributed computing systems.     

ELISA assay optimization using hyperbolic regression

The enzyme-linked immunosorbent assay (ELISA) is routinely used for estimation of specific protein concentration in research and in manufacturing. To optimize both the sensitivity of the assay and its usable dynamic range, it is necessary to adjust the concentrations of reagents, as well as other experimental conditions. Hyperbolic regression is a novel mathematical technique which gives the investigator a quantitative analysis of the assay's kinetic response to variations in reagents and conditions. The equations for hyperbolic regression are easily programmed on a computer spreadsheet or even on a scientific pocket calculator. Hyperbolic regression can be used to facilitate the initial optimization of the assay conditions, or to estimate the concentrations of unknowns on a routine basis directly from the standard curve, or to monitor the long-term degradation in activity of antibody reagents and antigen standards.     

Primer design for multiplex PCR using a genetic algorithm

Multiplex Polymerase chain reaction (PCR) is the term used when more than one pair of primers is used in a polymerase chain reaction. The goal of multiplex PCR is to amplify several segments of target DNA simultaneously and thereby to conserve template DNA, save time, and minimize expense. The success of the experiment is dependent on primer design. However, this can be a dreary task as there are many constrains such as melting temperatures, primer length, GC content and complementarity that need to be optimized to obtain a good PCR product. In our investigations, we found few primer design tools for multiplex PCR and there was no suitable tool for our partners who want to use a multiplex PCR genotypic assay. The tool draws on a genetic algorithm where stochastic approaches based on the concept of biological evolution, biological genetics and genetic operations on chromosomes are used to find an optimal solution for multiplex PCR. The presented experimental results indicate that the proposed algorithm is able to find a set of primer pairs that not only obey the design properties but also work in the same tube.     

多路高精度扩散炉温度控制系统的设计

针对传统的扩散炉温度控制系统的精度低、生产工艺控制能力差的现状,设计实现了扩散炉多路高精度温度检测控制系统。系统采用三路热电偶采集扩散炉内温度值并通过基于Smith预估的PID控制,控制三组加热装置的启停,以达到对炉温的控制,控制精度可达1‰,并采用液晶显示模块和按键组成人机交互界面。     

基于Web Service构建企业复合式应用

构建企业复合式应用面临两个问题：一是企业内部异构业务系统的整合;二是跨企业应用的集成。通过研究WebService利用XML标准封装数据,SOAP协议传输消息的特性以及对WebService支持的远程过程调用的互操作的分析,提出了一种基于’WebService构建企业复合式应用的模型,从而既能有效地整合企业内部异构系统,又能实现跨企业应用集成。     

Interaction between technology standardization and technology development: a coupling effect study

Technology standardization and technology development interact intimately. Understanding these interactions is fundamental to being able to seek the right solutions to questions about stimulating the advance of science and technology. After analyzing the impact that technology standardization and technology development have on each other, this paper asserts that coupling effects exist between technology standardization and technology development. A coupling model is proposed to examine the mechanism of the interaction between technology standardization and technology development. A seven-level scale for measuring coupling degrees is developed, as well. Furthermore, data from 38 industries in China are collected, in order to validate the proposed model. The newly developed scale is adopted to measure the degree of coupling in the selected industries. Finally, these industries are categorized into three groups based on their coupling degree values. Strategies about how to improve the coupling effects between technology standardization and technology development for each category are provided.     

Poly(dimethylsiloxane) microchip-based immunoassay with multiple reaction zones: Toward on-chip multiplex detection platform

In this work, a poly(dimethylsiloxane) (PDMS) microchip-based immuno-sensing platform with integrated pneumatic micro valves is described. The microchip was fabricated with multiple layer soft lithography technology. By controlling the activation status of corresponding valves, reagent flows in the microchannel network can be well manipulated so that immuno-reactions only take place at designated reaction zones (DRZs). Four DRZs are included in the prototype microchip. Since these DRZs are all isolated from each other by micro valves, cross contamination is prevented. Using the inner surface of the all-PDMS microchannel as immunoassay substrate, on-chip sandwich format solid phase immunoassay was performed to demonstrate the feasibility of this immuno-sensing platform. Mouse IgG and fluorescein isothiocyanate (FITC) were used as the model analyte and the signal reporter respectively. Only 10 μl sample is needed for the assay and low detection limit of 5 ng/ml (≈33 pM) was achieved though low-cost polyclonal antibodies were used in our experiment for feasibility study only. Much lower detection limit may easily be achieved by using high quality monoclonal antibodies. Through a simple yet effective comparison experiment, it was also found that high concentration BSA blocking solution (5% BSA in PBS buffer) can effectively suppress the non-specific binding in the surface of the microfluidic channels. The encouraging results from mouse IgG immunoassay proved the feasibility of our microchip design. With slight modification of the assay protocol, the same chip design can be used for multi-target detection and can provide a simple, cost-effective and integrated microchip solution for multiplex immunoassay applications.     

Ecology of technology: A perspective

Science and technology are on trial due to the rapid changes — neither university nor science lead developments in technology, the most advanced military technology has lost linkages with industries, the widened North-South gaps — they are all sources of crisis in the global ecological balance. The Euro-centric universalism is useless to solve the global technology problems.     

Computer documentation: Writing about technology

Eric Johnson is Professor of English and Dean of the College of Liberal Arts at Dakota State University. He is the Editor ofTEXT Technology, and he is the author of over one hundred articles and papers about computers, writing, and literary study. He can be contacted via e-mail as JohnsonE@dsuvax.dsu.edu.