The transient solution of time-dependent M/M/1 queues

The transient behavior of time-dependent M/M/1 queues is studied. The boundary probability function π₀(t), which is the probability that the queue is empty at time t, is shown with analyticity arguments to satisfy a Volterra-type integral equation. The boundary integral equation is derived, and a numerical algorithm is used to solve the integral equation and to find the expected queue size from π₀(t). The approach can be applied to many other types of time-dependent queues. Examples are given     

Solution for M/G/1 queues

M/G/1 type queueing systems are frequently found in the performance evaluation of communication systems. The authors develop a new solution method for these queues: their results are an alternative to both standard forms of exact analysis, and to diffusion approximations, while offering comparable computational complexity to the latter     

A pseudomatched filter model applied to the transient system ofhuman vision

A pseudomatched filter configuration is presented as a model for the transient system of the human visual perception. This model has resemblances to the Reichardt [1] and the Rashbass [2] model, but on the other hand the pseudomatched filter model is linear. The choice of the model is based on the shape of the psychophysically measured impulse response and on physiological and functional arguments. The parameters of the model are estimated for different data sets. The behavior of the model agrees with the experimental data in all essential aspects, and can be used for prediction and further modeling of the human visual system.     

Rare event analysis of batch-arrival queues

This paper deals with the analysis of small overflow probabilities in single-server queues with batch arrivals. First, for the class of GI ^X /G/1 queues we give analytical expressions for the decay rate (in the buffer size) of these probabilities. In case of Poisson arrivals, effective bandwidth results are deduced. Furthermore, we propose a change of measure which enables the execution of importance sampling in an asymptotically optimal way. Simulation results for a specific application show large speed-ups.     

应用于并行ADC性能扩展的一种比特滑动流水模数转换方法研究

根据现代通信对模数转换的高速、高分辨率性能要求,在对现有的并行式模数转换电路研究和改进的基础上,提出了一种比特滑动流水并行式模数转换方法,从而简化了电路结构、节省了器件、降低了功耗,更有利于集成化。时域仿真实验结果表明,运用该方法实现的ADC,其采样频率达到10Ms/s。     

基于OCDM混合1D/2D码的PON监控系统分析

主要讨论基于OCDM混合1D/2D码在PON监控系统中的使用及整体模型,该模型是在1D码、2D码基础上提出的,是1D码和2D码的结合体。利用混合1D/2D码技术对不同的用户分配不同的码字,以实现多用户、高信噪比的实时监控。     

A surface distortion analysis applied to the hoop/column deployablemesh reflector antenna

A practical approach is demonstrated for the deterministic analysis of surface distortions in reflector antennas, based on a first-order approximation to the aperture field phase. Measured pattern results from the 15-m-diameter hoop/column deployable mesh reflector antenna are used to demonstrate the accuracy which can be obtained with this surface distortion analysis. The only practical limitation of the first-order approximation is determined by the slope derivations of the distorted surface from the best-fit paraboloid     

Mθ/G/1/m and Mθ/G/1 queues with operating parameters depending on the queue length

M^θ/G/1/m and M^θ/G/1 queues are considered in the case when the service time and input flow parameters depend on the queue length and are determined at the instants of completion of the service of customers. With the help of an approach based on the idea of Korolyuk’s potential method, the Laplace transforms are found for the distribution of the number of customers in a system within the busy period and for the distribution function of the busy period. The mean duration of the busy period and the stationary distribution of the number of customers in a system are determined. An M^θ/G/1 system with one threshold of functioning mode switching is considered as a particular case. The obtained results are verified with the help of simulation models developed with the use of the GPSS World tools.     

Emulation-based transient thermal modeling of 2D/3D systems-on-chip with active cooling

State-of-the-art devices in the consumer electronics market are relying more and more on Multi-Processor Systems-On-Chip (MPSoCs) as an efficient solution to meet their multiple design constrains, such as low cost, low power consumption, high performance and short time-to-market. In fact, as technology scales down, logic density and power density increase, generating hot spots that seriously affect the MPSoC performance and can physically damage the final system behavior. Moreover, forthcoming three-dimensional (3D) MPSoCs can achieve higher system integration density, but the aforementioned thermal problems are seriously aggravated. Thus, new thermal exploration tools are needed to study the temperature variation effects inside 3D MPSoCs. In this paper, we present a novel approach for fast transient thermal modeling and analysis of 3D MPSoCs with active (liquid) cooling solutions, while capturing the hardware-software interaction. In order to preserve both accuracy and speed, we propose a close-loop framework that combines the use of Field Programmable Gate Arrays (FPGAs) to emulate the hardware components of 2D/3D MPSoC platforms with a highly optimized thermal simulator, which uses an RC-based linear thermal model to analyze the liquid flow. The proposed framework offers speed-ups of more than three orders of magnitude when compared to cycle-accurate 3D MPSoC thermal simulators. Thus, this approach enables MPSoC designers to validate different hardware- and software-based 3D thermal management policies in real-time, and while running real-life applications, including liquid cooling injection control.     

Transient analysis of the successful and blocked events in retrial queues

The phenomenon of repeated attempts arises naturally in telecommunication and computer networks. One aspect of the retrial feature is considered in this paper, where we investigate the transient behavior of the successful and blocked events made by the primary customers and the retrial customers.     

A Constructive Approach to Stabilizability and Stabilization of a Class of nD Systems

This paper presents a constructive approach to the problem of output feedback stabilizability and stabilization of a class of linear multidimensional (nD, n>2) systems, whose varieties of the ideals generated by the reduced minors are infinite with respect to not more than two variables. The main idea of the proposed approach is to decompose the variety of an nD system in this class into a union of several varieties, each of which is defined by polynomials in just two variables. The new method can be considered as a combination of Gröbner bases and existing results on two-dimensional (2D) digital filter stability tests and on stabilizability and stabilization of 2D systems. An example is illustrated.     

Complex finite-element method applied to the analysis of opticalwaveguide amplifiers

A complex finite-element method and a three-level model for erbium ions are applied to obtain gain and propagation constants for erbium-doped waveguide amplifiers (EDWA's). The complex refractive index profile includes the effect of the dopant polarization induced by the pump field. The method allows to consider arbitrary dopant density profile as well as the modal structure of the pump field. For different waveguide geometries we obtain gain curves as function of pump intensity as well as slight variations in the modal propagation constants. The threshold pump power is shown to be a function of the waveguide geometry, which agrees qualitatively with experimental results,     

Two-parameter dimensional analysis applied to the derivation of sensitivity invariants

The summed sensitivity invariants are derived by a 2-parameter dimensional analysis. This approach clarifies the limitation of these invariants to circuits with only two kinds of elements, and yields directly all generalisations to distributed or active networks.     

New constructions of 1D and 2D generalized Kravchenko-Kotel’nikov theorems on the basis of atomic function up(t)

New constructions of 1D and 2D generalized Kravchenko-Kotel’nikov sampling theorems based on atomic function up(t) are proposed and justified. The theorems are rigorously proved for both 2D and 1D cases. A simulation performed to analyze the construction and improvement of new series estimates shows their advantage over the classical Whittaker-Kotel’nikov-Shannon series.     

Alloy splitting of Te-DX in AlxGa1−xAs analysis using the deep level transient spectroscopy technique

The paper reports on a deep level transient spectroscopy analysis of Te-related DX centers in Al_xGa_1−xAs with aluminum composition x=0.40. As was shown from experimental results, the state energy of this trap shows a microscopic structure due to an alloy effect. A theoretical analysis based on a multi-step scheme has been made to explain the electron emission from a multiconfigurate center. Using this model, we derived the binding energies of the splitted Te-DX states in the alloy material studied.     

Delay analysis for ATM queues with random order of service

The delay in a discrete-time ATM queue of GI-D-1 type with random order of service is analysed by means of a generating functions approach. The analysis directly yields closed-form formulas for the moments of the delay. The proposed approach may also be a basis for the delay analysis of more complicated discrete-time queueing models with random order of service     

Throughput analysis and optimal design of Banyan switches withbypass queues

A Banyan switch with bypass queue can overcome the problem of head of line blocking. This paper presents the throughput analysis for such a switch and the optimal window size for the bypass queue is also obtained. Moreover, to reduce the effect of the internal blocking and to increase the throughput, a parallel Banyan switch with bypass queue is also discussed and analyzed