Capacity evaluation of packet-switched CDMA system

In this letter, an extended definition for packet-switched CDMA system capacity based on the protocol stack characteristics is proposed. According to the extended definition, the capacity of the packet-switched CDMA system for different ARQ protocols and different channel models is investigated. The results show that, compared with the traditional definition, the extended definition is more appropriate for describing the packet-switched CDMA network capacity     

Comments on “Explicit asymmetric bounds for robust stabilityof continuous and discrete-time systems”

Referring to the original paper by Gao and Antsaklis (ibid., vol. 38, p. 332-5, 1993), the authors state that Theorem 2 is incorrectly stated. A correct version of the theorem is provided     

Simple method to evaluate coupling functions atantireflection-coated diode facets facing grating reflectors of longexternal cavities

The spectral content of the reflected light from a grating, positioned at a distance much longer than the diode length to form an external-cavity semiconductor laser, has been studied. The analytical expressions derived show that the coupling coefficient at the antireflection (AR)-coated diode facet facing the extended cavity can be divided into two factors, of which one is due to the off-overlapping between the centers of the diode mode and its reflected counterpart, and the other is due to the alteration of the wave vector after being dispersed by the grating     

Modeling Starch Digestograms: Computational Characteristics of Kinetic Models for in vitro Starch Digestion in Food Research

Starch digestion is mostly investigated with in vitro techniques, and time‐course measurements are common. These yield digestograms that are modeled by theoretical, semitheoretical, and empirical kinetic equations, many of which are reviewed here. The Duggleby model has Michaelis–Menten functions, and its dependent variable is on both sides of the equation with no apparent parameter for maximum digestible starch (D_∞). The Gaouar and Peleg models are equivalent. They predict both the initial digestible starch (D₀) and D_∞, and an average digestion rate, but they can reveal "biratial" digestions. The first‐order kinetic model exhibits diverse predictabilities and, when linearized, D_∞ is sometimes equated to 100 g/100 g dry starch (100%), it yields an average rate of digestion and can predict negative D₀. The log of slope (LOS) model is unique in revealing the rapid‐to‐slow digestion rate phenomenon, but without guidelines to identify such. The LOS model does not sometimes use all the digestogram data, can predict D_∞ greater than 100%, and returns zero digestion rate for some digestograms. However, some starchy materials exhibit a slow‐to‐rapid digestion rate phenomenon, as demonstrated with an example. The modified first‐order kinetic model uses all the digestogram data with practical constraints (D₀ ≥ 0 g/100 g dry starch; D_∞ ≤ 100 g/100 g dry starch), describes all digestograms, and yields an average digestion rate, but it can also be used for "biratial" digestions. In addition, the logistic and Weibull models are discussed. Using some published data, the computational characteristics of these commonly used models are presented with objective parameters to guide choices.     

New class of codes suitable for computer error control

A new concept of generalised orthogonality is proposed and a class of generalised orthogonal codes based on SBIBD theory is developed     

Jatropha curcas L. oil extracted by switchable solvent N,N-dimethylcyclohexylamine for biodiesel production

Biodiesel, which is a renewable and environmentally friendly fuel, has been studied widely to help remedy increasing environmental problems. One of the key processes of biodiesel production is oil extraction from oilseed materials. Switchable solvents can reversibly change from molecular to ionic solvents under atmospheric CO_2,and can be used for oil extraction. N, N-dimethylcyclohexylamine(DMCHA), a switchable solvent, was used to extract oil from Jatropha curcas L. oil seeds to produce biodiesel. The appropriate extraction conditions were:1:2 ratio of seed mass to DMCHA volume, 0.3–1 mm particle size, 200 r·min-1agitation speed, 60 min extraction time, and 30 °C extraction temperature. The extraction ratio was about 83%. This solvent extracted the oil more efficiently than hexane, and is much less volatile. By bubbling CO_2 under 1 atm and 25 °C for 5 h, the oil was separated, and DMCHA was recovered after releasing CO_2 by bubbling N_2 under 1 atm and 60 °C for 2 h. The residual solvent content in oil was about 1.7%. Selectivity of DMCHA was evaluated by detecting the protein and sugar content in oil. Using the oil with residual solvent to conduct transesterification process, the oil conversion ratio was approximately 99.5%.     

抗毁网状WDM网络中的光纤级P-Cycles优化设计

为降低保护切换代价和提高故障恢复时间,提出了以光纤级P-Cycle来实现网络保护;研究了工作路由与光纤级P-Cycle放置联合优化的设计问题,给出了ILP数学模型。为降低计算的复杂度,采用了一种简单有效的方法:根据跳数预先选择工作路由候选集及环的有效性和长度预先选择P-Cycle候选集。仿真结果表明光纤级P-Cycle设计相比于波长级P-Cycle设计保护切换代价大大降低。     

粗集在交通事故黑点成因分析中的应用

交通事故黑点的形成原因多种多样,每一个事故多发点都有其形成的最大诱因。作为交通安全管理工作的重要任务,交通事故黑点的鉴别与改善是预防交通事故发生、减少交通事故损失的有效手段。该文针对交通事故多发点成因的复杂性和多样性,提出通过粗集来对公路交通中的不利因素进行筛选,找到形成事故多发点的最大诱因,从而有针对性地进行整治,能够有效地节约时间和费用,避免不必要的人力、物力浪费。     

广义Haar子波

研究了最简单的规范正交子波——Haar子波的简单广义化问题,首先提出尺度系数函数新概念,并引进时移因子,将Haar子波进行拓展而得到一类新的规范正交子波:广义Haar子波;从理论上论证这种简单广义化方法的合理性与广义Haar子波的一些基本性质;给出了广义子波系在时域和频域的闭式表达。