Measurement-based network monitoring and inference: scalability andmissing information

Using measurements collected at network monitors to infer network conditions is a promising approach for network-centric monitoring. In this context, an important question arises: given the number and locations of network monitors, how much network management resources (e.g., the number of measurements) are needed to obtain an accurate estimate of network states? We define the scalability of measurement-based network monitoring as the growth rate of the number of measurements required for accurate network monitoring/inference with respect to the size of a network. We develop a framework for investigating the scalability in the context of multicast inference with the monitors at the edges of a network. In such a framework, network monitoring/inference can be formulated as probability density estimation of network states. The growth rate is characterized through the sample complexity, which is the number of measurements needed to accurately estimate the density. The missing data framework is introduced to estimate the growth rate, where the missing data reflect unavailable measurements at the unobservable nodes without resident monitors, and the underlying nodal packet losses. We show that when the missing information is mainly due to the number of unobservable nodes, the number of measurements needed grows linearly with the size of the network, and the measurement-based inference approach is, thus, scalable. When the missing information is mainly due to the underlying nodal packet losses, the number of measurements needed grows faster than linear with the size of the network, and the measurement-based inference approach is, thus, not scalable. Our results provide guidelines for accessing feasibility of the measurement-based inference approach, and the number of probes required. We give numerical examples to illustrate some of our results     

带疏水泵加热器出口主凝结水焓的计算方法

以火电厂热力系统热力单元矩阵分析法为基础，提出了一种更为科学有效的带疏水泵加热器出口主凝结水焓分析计算的新方法，应用表明，其结论与常规算法完全一致，图2表1参3。     

墙改之路越走越宽标准严格政策绿灯

四部委发布实施<节能标准>的通知 日前,建设部、国家计委、国家经贸委、财政部联合发布了关于实施<夏热冬冷地区居住建筑节能设计标准>的通知.     

拉伸速率对PP/GB复合材料力学性能的影响

应用Instron材料试验机考察了室温下拉伸速率对玻璃微珠填充聚丙烯复合材料的弹性模量和屈服强度的影响，结果表明，随着微珠含量的增加，试样的弹性模量（Ec）增大，且与拉伸应变速率呈近乎幂律函数关系，而屈服强度（бyc）则随着微珠体积分数（Φf）的增加呈线性函数形式下降，并随着拉伸应变速率的增加呈幂律函数形式提高，此外，讨论了Ec、Φf与бyc三者之间的关系。     

纳米ZnO薄膜制备及液态源掺杂

用真空蒸发法在玻璃和单晶硅片 (10 0 )上制备Zn薄膜 ,然后对Zn薄膜进行氧化、热处理获得纳米ZnO薄膜。对在硅片上制备的Zn薄膜一次性进行高温掺杂、氧化获得纳米ZnO∶P和ZnO∶B薄膜。研究不同氧化、掺杂温度和时间对薄膜结构、电学性能的影响。结果表明 :氧化温度和时间对ZnO薄膜结构影响较大 ,液态源掺P可明显改善纳米ZnO薄膜的导电性能、结构特性和化学组分     

NiCuZn铁氧体和银内电极的共烧行为

NiCuZn铁氧体正作为磁介质广泛地应用于低烧多层片式电感，因此有必要对其与银内电极的共烧行为进行研究。该文主要介绍NiCuZn铁氧体／银内电极多层复合体共烧过程中的烧结收缩、界面反应、扩散对介质性能的影响。尖晶石结构中存在相当数量的空位，这为银离子提供了一定的溶解度，因此在共烧过程中银对铁氧体的相组成影响较小。银对铁氧体性能的影响体现在两个方面。一方面是由于银具有相对低的烧结温度，从而在烧结过程中起到助烧剂的作用，促进致密化过程，提高烧结体的密度和磁导率；另一方面，银促使铁氧体中的铜在晶界处析出，导致晶界处应力，使磁导率降低，晶粒生长也被一定程度地抑制。     

ANALYSIS AND PROCESSING OF LMF－COSTAS STEPPED FREQUENCY RADAR SIGNAL

Linear Modulated Frequency (LMF) Costas Stepped Frequency Radar (SFR) signal is introduced. Its ambiguity function is derived and analyzed in detail and its feasibility is validated in theory. The scheme of the proposed signal processing is also presented. The results of theoretic analysis and simulation show that, by using the proposed signal and increasing the bandwidth of the total stepped frequency, the ambiguity sidelobe is well suppressed and the range-velocity coupling in the stepped frequency radar is also greatly weakened.     

A One‐Kilobit PQR‐CMOS Smart Pixel Array

The photonic quantum ring (PQR) laser is a three dimensional whispering gallery (WG) mode laser and has anomalous quantum wire properties, such as microampere to nanoampere range threshold currents and √T‐dependent thermal red shifts. We observed uniform bottom emissions from a 1‐kb smart pixel chip of a 32×32 InGaAs PQR laser array flip‐chip bonded to a 0.35 µm CMOS‐based PQR laser driver. The PQR‐CMOS smart pixel array, now operating at 30 MHz, will be improved to the GHz frequency range through device and circuit optimization.     

Electromagnetic micromirror array with single-crystal silicon mirror plate and aluminum spring

We have designed and fabricated an addressable 4 /spl times/ 4 array of micromirrors capable of providing up to 90/spl deg/ of angular deflection. Each micromirror comprises a single-crystalline silicon mirror plate supported by aluminum springs, which provides an extremely flat reflective surface and a compliant spring material that enables the integration of the device into a limited area without mitigating its performance (i.e., total angular deflection). The device is fabricated using a combination of surface and bulk micromachining processes, such as electroplating, bulk wet etching and XeF/sub 2/ etch processes. Selective actuation is accomplished by the use of an electrostatic clamping force on each mirror plate. A mirror rotation angle of more than 80/spl deg/ can be obtained by applying an external magnetic field, and this angle can be further increased by the use of an electrostatic force. The designed structure can be used in microphotonic applications.