Pricing and distributed QoS control for elastic network traffic

We study a processor-sharing model in which users choose between a high- and a low-priority service, based on their utility functions and prices charged by the service provider. The latter aims at revenue maximization. The model is motivated by file transmissions in data networks with distributed congestion control.     

Single-server queues with spatially distributed arrivals

Consider a queueing system where customers arrive at a circle according to a homogeneous Poisson process. After choosing their positions on the circle, according to a uniform distribution, they wait for a single server who travels on the circle. The server's movement is modelled by a Brownian motion with drift. Whenever the server encounters a customer, he stops and serves this customer. The service times are independent, but arbitrarily distributed. The model generalizes the continuous cyclic polling system (the diffusion coefficient of the Brownian motion is zero in this case) and can be interpreted as a continuous version of a Markov polling system. Using Tweedie's lemma for positive recurrence of Markov chains with general state space, we show that the system is stable if and only if the traffic intensity is less than one. Moreover, we derive a stochastic decomposition result which leads to equilibrium equations for the stationary configuration of customers on the circle. Steady-state performance characteristics are determined, in particular the expected number of customers in the system as seen by a travelling server and at an arbitrary point in time.     

1.30μmDFB激光器组件的设计和制做及其工作原理

本文自行设计和制作了１．３０μｍＤＦＢ激光器组件的讨论了光隔离和光耦合原理。由于采用的激光器－光隔离器－光纤的一体化结构，大大增加了该组件的可用性。在实验中得到高达５５％的耦合效率。     

Analysis of a demodulation system for Fiber Bragg Grating sensors using two fixed filters

The analysis of a demodulation system for Fiber Bragg Grating sensors based on two fixed spectral filters has been carried out both theoretically and experimentally. Different system configurations were analyzed by modifying the spectral position of the filters as well as the optical power-level of the signal reaching the two photo-detectors. Measurements with integration times that varied from 0.01 to 1 s have been compared with the low-frequency limit predicted for long-term operation. Comparisons between simulated and experimental results show good agreement, and extrapolations indicate that it should be possible to achieve an operating spectrum range of the order of 7 nm, with uncertainties equivalent to less than 2 pm in measurements of the sensor peak position.     

遗传程序设计中分布式染色体的一个应用

对一类遗传程序设计问题，提出了简单等长的分布式染色体，取代复杂变长的树结构染色体，使演化算子操作更方便，个体复杂度得到有效控制．用该染色体形式解决割草问题，分析了分布式染色体带来的一些性质，并给出了很好的计算结果．     

倾斜Bragg光纤光栅反射谱特性理论和实验研究

光纤Bragg光栅在通信和传感领域有着广泛的应用。根据倾斜光纤Bragg光栅的结构特点，利用耦合模原理，运用传输矩阵法，模拟分析了倾斜角度对光纤Bragg光栅反射特性的影响，并用实验对模拟结果进行了验证。实验和模拟结果表明：随着倾斜角的增大，中心反射波长向长波方向移动，反射带宽变窄，反射率减小。这个结论对倾斜Bragg光纤光栅的生产和应用有一定的指导作用。     

光纤光栅最佳切趾函数的研究

采用耦合模理论，给出了用传输矩阵法计算光纤Bragg光栅（FBG）特性的方法，进而得到了在不同切趾函数形式下的FBG反射谱的数值解。通过理论分析，给出了最佳切趾函数反射谱和群时延特性曲线。     

用超磁致伸缩调谐光纤光栅的光分/插复用器

提出并研究了一种新型多信道切换的全光分/插复用器,它主要由光纤Bragg光栅(FBG)和一对光环行器组成.采用了一种高效的超磁致伸缩材料(GMM)使FBG产生有效的Bragg波长偏移.用控制电流来调控FBG的应变和Bragg波长偏移.用4只相同的FBG与波长叠加技术相结合,可建立能提供15种不同下路信道方式的OADM.     

Fiber Optical Bragg Grating Refractometer

We have demonstrated an evanescent field refractive indexfiber sensor comprising a 42-mm Bragg grating in an etched fiber together with a tunable Distributed Bragg Reflector (DBR) laser. Characterization of different aqueous sucrose solutions resulted in a resolution of roughly 10 mM sucrose. The sensor in the presented form has a theoretical sensitivity of higher than 10 5 refractive index unit (riu) in a refractive index region close to the cladding index of the fiber. However, the technique allows for an even higher sensitivity than 10 6 riu with a proper signal processing scheme.     

Characterisation of Sol-Gel TiO2 Films by Etching

This article describes the SmartKom Companion, one of three demonstrators developed within the SmartKom project whose goal has been to provide an intuitive and intelligent interface for non-expert users to everyday computer-based applications in different scenarios of use. Conceived for the SmartKom Mobile scenario, the Companion allows intuitive multimodal interaction for drivers and pedestrians. The development of the SmartKom prototypes was constantly accompanied by Wizard-of-Oz experiments as well as system evaluations at different stages of the project. Some usability evaluation results relative to the SmartKom Companion will also be presented.