On the design of sliding mode control schemes for quantum resonantconverters

The design of sliding mode control schemes for quantum resonant converters is introduced hy means of two different approaches. First, an easy-to-use procedure for devising nonlinear control structures is established, using Lyapunov's well-known stability criteria. Second, an alternative method that provides linear sliding surfaces is also developed, considering reaching, existence, and stability conditions. The application of both control design techniques is illustrated in detail by means of three selected examples. The advantages and drawbacks of the resulting control circuits are examined. Simulation and experimental results corroborate the expected features of the close-loop quantum converters     

Acknowledgment schemes for window flow control in a quasi-M/D/1cut-through switching network

Window flow control in a quasi-M/D/1 cut-through switching network with noisy channel is discussed. Two acknowledgment schemes for window edge control at the entry node are proposed, and their various properties investigated     

On asymptotic optimality of a sliding window variation ofLempel-Ziv codes

The authors modify the algorithm of Z. Ziv and A. Lempel (1977), LZ77, restricting pointers to start only at the boundary of a previously parsed phrase in a window. Although the number of parsed phrases should increase more than those in LZ77, the number of bits needed to encoded pointers is considerably reduced since the number of possible positions to be encoded is much smaller. It is shown that, for any stationary finite state source, the modified LZ77 code is asymptotically optimal with the convergence rate O(log log M/log M), where M is the size of a sliding window     

Self-stabilizing sliding window ARQ protocols

It is shown that implementing a practical self-stabilizing sliding window protocol requires a bound on the maximum delay or maximum memory of the communication channel involved. This motivates using communication channel models that incorporate a delay or memory bound. For such models, two new ARQ protocols are presented that self-stabilize by using 1 bit of overhead in each transmitted message. The protocols operate like selective repeat ARQ, except that when a fault places them in an incorrect (unsafe) state, the additional bit in the protocol messages allows automatic recovery. Following a transient fault, the bounded delay protocol stabilizes within four round-trip times. The bounded memory protocol stabilizes after sending at most 2(K+n) messages, where K the is maximum number of messages that can be stored in one direction on the channel, and n is the window size of the sender     

Adaptive feedforward and feedback control schemes for sliding mode controlled power converters

A major disadvantage of applying sliding mode control to dc/dc converters is that the steady-state switching frequency is affected by line and load variations. This is undesirable as it complicates the design of the input and output filters. To reduce switching frequency deviation in the events of line and load variations, an adaptive feedforward control scheme that varies the hysteresis band according to the change of line input voltage and an adaptive feedback control scheme that varies the control parameter (i.e., sliding coefficient) according to the change of the output load are proposed. This paper presents a thorough investigation into the problem and the effectiveness of the proposed solutions. In addition, methods of implementing the proposed adaptive control strategies are discussed. Experimental results confirm that the adaptive control schemes are capable of reducing the switching frequency variations caused by both line and load variations.     

Optimal flow control schemes that regulate the burstiness oftraffic

The problem of designing burst reducing flow controllers for traffic in an ATM network is studied. By requiring that the output flow obey certain burstiness constraints, it is shown that an optimal design exists and that it can be easily implemented in real time. Two versions of the problem are considered. The first one places constraints on the buffer size and the second one on the maximum delay that a cell can experience. Both problems are solved for arbitrary traffic processes. To treat the problems in this generality the authors introduce reflection mappings and use them, in a rather novel way, to establish optimality results. As a by-product of the analysis and methods, the optimality of the popular leaky bucket flow control scheme is also established     

Integration of rate and credit schemes for ATM flow control

The authors make the case in favor of an integrated approach to ATM flow control. They contend that both rate and credit schemes have advantages and disadvantages, and that to a large extent they can be viewed as complementary     

Nested sliding window protocols with packet fragmentation

A single-hop OSI structured network with multiple layers of sliding window flow control and packet fragmentation between layers is analyzed. An approximation algorithm is presented to hierarchically reduce the network to a single queue whose performance characteristics represent the original network. Network transmission characteristics are restricted to Erlang distributions. Validation against exact and simulation results showed that the approximation algorithm has a satisfactory error level     

Signed sliding window algorithms for modulo multiplication

The signed sliding window (SSW) number system for accelerating long-wordlength modulo multiplication is introduced. Compared with the previously published unsigned sliding window (USW) number system, SSW reduces the average number of nonzero digits in a number or reduces the amount of pre-computation required. In addition, how USW and SSW can be combined advantageously with Montgomery's algorithm for modulo reduction is described     

基于滑动窗口的动态数据挖掘

提出了动态数据挖掘的体系结构和动态数据挖掘滑动窗口算法;并进行了数据挖掘仿真实验,验证了系统的高效性和实用性.     

一种基于LMMSE滑动窗的信道估计算法

LTE-A下行传输中采用的多达8天线端口的增强型MIMO技术,为了保证对LTE系统的后向兼容以及确保UE对最大8天线端口和反馈更大的带宽信道状态信息(CSI),引入了新的参考信号CSI-RS。分析了LMMSE信道估计算法,提出了一种基于LMMSE滑动窗的信道估计算法。仿真结果表明,该算法既节约了导频资源占用率,又提高了系统的发送效率。     

一种基于滑动窗口技术的入侵检测方法

网络数据流在一段时间内会发生概念性变化,这可能会降低入侵检测的精度.针对网络数据流的这一特性,提出了一种能识别并适应概念飘移的基于滑动窗口的入侵检测方法,它能根据数据流的概念漂移的状况自动调整训练窗口并对检测模式进行及时的更新.     

基于滑动窗口的移动自组网的自愈密钥发布机制

针对MANET(移动自组网)中存在用户实际生命期跨越2个会话窗口的现象,同时为了降低自愈密钥移动自组网管理者的负担,提出了基于滑动窗口的自愈密钥发布机制;建立了双向散列密钥链模型;利用控制参数,实现了t-撤销能力.安全分析表明,在解决用户跨步问题的前提下,没有降低模型的安全性.由于管理者对跨步用户仅需传递一次初始私有信息,避免了会话重建过程中的再次传递,降低了通信开销.     

一种基于滑动窗口的不确定数据流聚类算法

针对不确定数据流上的聚类问题提出了一种新的聚类算法SWCUS,它采用滑动窗口缓存一段时间内的元组作为聚类对象,只存储新到达的数据,"淘汰"过时数据,以便获得高质量的聚类结果。另外它还应用k-means算法来生成初始微簇并且提出了一种新的离群点机制来排除离群点。实验结果表明,SWCUS算法与同类型的算法相比有较好的聚类效果和较快的聚类速度,而且其自身拥有很强的可伸缩性。     

A sliding window decorrelating receiver for multiuser DS-CDMAmobile radio networks

We detail the development of a near-far (NF) resistant sliding window decorrelating algorithm (SLWA) that overcomes the near-far problem (NFP) pertaining to the conventional linear correlation receiver (CLCR) and alleviates some of the limitations of the standard decorrelator. The SLWA architecture is extended to incorporate differentially coherent multipath (RAKE) diversity combining techniques and hence achieves simultaneous rejection of multiuser and multipath interference. This paper also presents a novel algorithm for updating the decorrelator coefficients using a fully parallel architecture. We present a mathematical model for the performance of a sliding window scheme, the main contribution of which is the analysis of finite sequence length multipath decorrelation under the practical limitation of incomplete RAKE combining. In addition to numerical results, we present results pertaining to capacity improvements achieved over the CLCR, derived from a simulation of a multiuser direct-sequence code-division multiple-access (DS-CDMA) mobile radio system     

一种不确定数据流子空间聚类算法

提出了基于滑动窗口的不确定数据流子空间聚类算法USSC,它应用采样时加权值的方法来选择初始化聚类中心点,采用滑动窗口SW缓存一段时间的元组作为聚类对象,并提出一种新的离群点处理机制来排除离群点Opo为适应不确定数据流元组不确定特性,该算法使用基于隶属度的非分割聚类方法来确定一个元组只能划分到一个簇中.试验结果表明,USSC算法与同类型的算法相比有较好的聚类效果和较快的聚类速度,而且其自身拥有很强的可伸缩性.     

针对滑动窗口算法的椭圆曲线密码故障分析

基于符号变换故障攻击原理,针对采用滑动窗口算法实现点乘运算的椭圆曲线密码,当故障位于倍点运算时,给出一种能够解决"零块失效"问题的改进故障分析方法,实验结果表明15次故障注入即可恢复192bit完整密钥;当故障位于加法运算时,提出一种新的故障分析方法,实验结果表明1次故障注入可将密钥搜索空间降低27~215。该方法对其他使用滑动窗口算法的密码算法故障攻击具有借鉴意义。     

A channel estimation using sliding window approach and tuningalgorithm for MLSE

A simultaneous sliding window channel estimation and timing adjustment method is proposed for adaptive maximum-likelihood sequence equalizer (MLSE) in the global system for mobile communication (GSM) system, and also a tuning scheme based on least mean squared (LMS) algorithm is presented in order to improve the performance of equalizer. Simulation results show that the proposed channel estimation technique is effective for channel estimation of the adaptive equalizer     

基于预测和滑动窗口的轨迹差分隐私保护机制

为解决轨迹差分隐私保护中存在的隐私预算与服务质量等问题,提出了一种融合预测扰动的轨迹差分隐私保护机制。首先,利用马尔可夫链和指数扰动方法预测满足差分隐私和时空安全的扰动位置,并引入服务相似地图检测该位置的可用性;如果预测成功,则直接采用预测位置替代差分扰动的位置,以降低连续查询的隐私开销并提高服务质量。在此基础上,设计基于w滑动窗口的轨迹隐私预算分配机制,确保轨迹中任意连续的w次查询满足ε-差分隐私,解决连续查询的轨迹隐私问题。此外,基于敏感度地图设计一种隐私定制策略,通过自定义语义位置的隐私敏感度,实现隐私预算的量身定制,从而进一步提高其利用率。最后,利用真实数据集对所提方案进行实验分析,结果显示所提方案提供了更好的隐私保护水平和服务质量。