Applying Analytical Hierarchy Process to a WiMAX Performance Evaluation Model

Evaluating performance of individual features of WiMAX technology is a topic of widespread discussion. Currently, there is no quantitative way of measuring WiMAX technology so that wireless operators can meet their design objectives. This paper outlines a set of design criteria for WiMAX and provides a decision-making aid that ranks the importance of criteria using Analytic Hierarchy Process (AHP). This ranking should sufficiently reflect market expectations of the relative importance of various design criteria. A model integrating AHP priorities with enhanced Data Envelopment Analysis (DEA) is the basis for formulating a technological value in simple,comparable format. A case study is provided to show how this technological value is used to evaluate a three year network deployment plan. In the future, this model could be extended to WiMAX equipment suppliers for the purpose of validating performance targets of individual criteria, and enhancing supplier roadmaps for future network development.     

A 2.1-6 GHz SiGe BiCMOS low-noise amplifier design for a multi-mode wideband receiver

正A wideband low-noise amplifier(LNA) with ESD protection for a multi-mode receiver is presented.The LNA is fabricated in a 0.18-μm SiGe BiCMOS process,covering the 2.1 to 6 GHz frequency band.After optimized noise modeling and circuit design,the measured results show that the LNA has a 12 dB gain over the entire bandwidth, the input third intercept point(IIP3) is -8 dBm at 6 GHz,and the noise figure is from 2.3 to 3.8 dB in the operating band.The overall power consumption is 8 mW at 2.5 V voltage supply.     

The Chitinolytic Activities of Streptomyces sp. TH-11

Chitin is an abundant biopolymer composed of units of N-acetyl-D-glucosamine linked by β-1,4 glycosidic bonds. Chitin is the main component of the shells of mollusks, the cell wall of fungi and yeast and of the exoskeleton of crustaceans and insects. The degradation of chitin is catalyzed by chitinases that occur in a wide range of organisms. Among them, the chitinases from microorganisms are extremely important for the degradation and recycling of the carbon and nitrogen trapped in the large amount of insoluble chitin in nature. Streptomyces sp. TH-11 was isolated from the sediment of the Tou-Chien River, Taiwan. The chitinolytic enzyme activities were detected using a rapid in-gel detection method from the cell-free preparation of the culture medium of TH-11. The chitinolytic enzyme activity during prolonged liquid culturing was also analyzed by direct measurement of the chitin consumption. Decomposition of the exoskeleton of shrimps was demonstrated using electron microscopy and atomic force microscopy.     

FH-UDS催化剂的工业应用与器外再生

介绍了FH-UDS催化剂在250万t/a柴油加氢装置上的首次工业应用和器外再生后的运转情况。自2006年8月投产至2009年11月装置平稳运转39个月,其间产品质量合格,达到了生产清洁柴油的目的,能耗较低。经过器外再生后的FH-UDS催化剂,活性恢复较好,依然能满足清洁柴油生产的要求,说明FH-UDS催化剂具有良好的再生性能。     

Design of high efficiency dual-mode buck DC-DC converter

A buck DC-DC switching regulator with high efficiency is implemented by automatically altering the modulation mode according to load current,and it can operate with an input range of 4.5 to 30 V.At light load current,the converter operates in skip mode.The converter enters PWM mode operation with increasing load current.It reduces the switching loss at light load and standby state,which results in prolonging battery lifetime and stand-by time.Meanwhile, externally adjustable soft-start minimizes the inru...     

高原隧道工程机械尾气排放现场测试研究

高原隧道工程机械尾气排放CO和烟雾的现场测试对隧道通风系统设计及隧道施工所需的挖掘机、装载机和自卸汽车数量的匹配有重要的工程价值。以西格线中国铁路第一长隧——关角隧道为依托,进行了多种挖掘机、装载机和自卸汽车CO与烟雾尾气排放的现场测试,测试结果为铁路、公路隧道施工规范中"海拔高度修正系数"在3600～3800m的范围内取值提供依据和参考,对我国在高原地区修建隧道有一定的参考作用。     

A decision tree method for building energy demand modeling

This paper reports the development of a building energy demand predictive model based on the decision tree method. This method is able to classify and predict categorical variables: its competitive advantage over other widely used modeling techniques, such as regression method and ANN method, lies in the ability to generate accurate predictive models with interpretable flowchart-like tree structures that enable users to quickly extract useful information. To demonstrate its applicability, the method is applied to estimate residential building energy performance indexes by modeling building energy use intensity (EUI) levels. The results demonstrate that the use of decision tree method can classify and predict building energy demand levels accurately (93% for training data and 92% for test data), identify and rank significant factors of building EUI automatically. The method can provide the combination of significant factors as well as the threshold values that will lead to high building energy performance. Moreover, the average EUI value of data records in each classified data subsets can be used for reference when performing prediction. One crucial benefit is improving building energy performance and reducing energy consumption. Another advantage of this methodology is that it can be utilized by users without requiring much computation knowledge.     

Heat transfer and thermal storage behaviour of gypsum boards incorporating micro-encapsulated PCM

In the application of energy storage and thermal environmental control, PCM (Phase Change Material) is a very promising material choice. This study incorporated mPCM (micro-encapsulated PCM) into gypsum to make mPCM gypsum board and then investigated the physical properties, heat transfer and thermal storage behaviour. The major control parameters are wall temperatures and the weight percentages of mPCM added to the gypsum boards. A melting fraction correlation, reduced from our test data and based on Stefan number (Ste), subcooling (Sb) and Fourier number, is proposed. It shows that case with a higher Ste or Sb can have a higher heat transfer through the hot wall. Thermal storage behaviour of mPCM gypsum boards is then analyzed.     

城市规划实施效果评价研究综述

有关城市规划实施效果评价的研究一直被忽视,原因在于过去规划理论的研究多将重点放在如何制定规划而不是如何使用规划上,加上城市运作过程极为复杂,使人们很难将规划对城市发展的影响独立于其他影响因子之外加以检视,因此在现实中进行城市规划实施效果的评价难度极大。对此,Hopkins教授提出了四个评价规划是否产生作用的准则:效果、净利益、内在效度和外在效度,并构建了一个分析框架,从理论和概念上对城市规划的实施效果进行评价。此外,还可以通过计算器仿真及分析演绎,探讨规划对城市发展的影响。     

大城市中心区步行街区交通组织研究

本文针对我国大城市中心区步行街区建设情况及其引发的交通矛盾,在分析步行街区交通特征的基础上,提出解决步行街区交通组织基本策略,从内部交通网络、内部与周围道路交通衔接、静态交通等方面提出了步行街区的交通组织对策,并从步行街区的布局、道路规划、出入口规划设计等方面探讨了步行街区的交通规划与设计,最后结合福州市三坊七巷步行街区交通组织进行实例分析。