Global Millimeter-Wave Precipitation Retrievals Trained With a Cloud-Resolving Numerical Weather Prediction Model, Part I: Retrieval Design

This paper develops a global precipitation rate retrieval algorithm for the advanced microwave sounding unit (AMSU), which observes 23-191 GHz. The algorithm was trained using a numerical weather prediction (NWP) model (MM5) for 106 globally distributed storms that predicted brightness temperatures consistent with those observed simultaneously by AMSU. Neural networks were trained to retrieve hydrometeor water-paths, peak vertical wind, and 15-min average surface precipitation rates for rain and snow at 15-km resolution at all viewing angles. Different estimators were trained for land and sea, where surfaces classed as snow or ice were generally excluded from this paper. Surface-sensitive channels were incorporated by using linear combinations [principal components (PCs)] of their brightness temperatures that were observed to be relatively insensitive to the surface, as determined by visual examination of global images of each brightness temperature spectrum PC. This paper also demonstrates that multiple scattering in high microwave albedo clouds may help explain the observed consistency for a global set of 122 storms between AMSU-observed 50-191-GHz brightness temperature distributions and corresponding distributions predicted using a cloud-resolving mesoscale NWP model (MM5) and a two-stream radiative transfer model that models icy hydrometeors as spheres with frequency-dependent densities. The AMSU/MM5 retrieval algorithm developed in Part I of this paper is evaluated in Part II on a separate paper.     

Radio-Over-MMF Techniques—Part II: Microwave to Millimeter-Wave Systems

Microwave to mm-wave radio carriers are commonly employed for creating high-capacity picocell wireless networks. Advanced radio-over-fiber (RoF) techniques can efficiently generate and transport such carriers, and deliver them to simplified antenna stations. As in in-building networks multimode fiber is predominantly used, adequate radio-over-multimode fiber (RoMMF) techniques are required to overcome the modal dispersion in multimode fiber links. The optical frequency multiplying technique is introduced; it is relatively simple to implement, yet it is shown to be robust against the modal dispersion, and it is able to generate very pure microwave carriers while requiring only moderate speed electronics. Thus, it can convey high data rates in comprehensive modulation formats on multiple-GHz carriers in MMF networks. It offers simultaneous operation at multiple radio standards, and capabilities for dynamic adaptation of the radio link parameters such as carrier frequency, transmit power, and other antenna site functions by means of an embedded control channel. Moreover, in combination with optical routing it enables dynamically adjustable network configurations for flexible wireless service delivery.      

MOSFET Performance Scaling—Part II: Future Directions

The analytical MOSFET intrinsic delay introduced in Part I of this paper is used to examine the tradeoffs between key device elements required in order for the performance scaling trend to continue in future high-performance CMOS generations. A scaling scenario based on contacted source/drain gate pitch is presented and used to examine the prospects of MOSFET performance in the future nodes. It is shown that, from 32-nm node onwards, MOSFET performance will counterscale, mainly due to increase in the parasitic gate capacitance as a result of proximity of the gate and source/drain electrodes. As a case study, the dependence of the transistor performance on various device parameters at the 32-nm node is analyzed. Reducing the fringing capacitance is shown to be the most effective approach to meet the required transistor delay.     

A Biologically Inspired Compound-Eye Detector Array—Part II: Statistical Performance Analysis

This is the second part of our paper. In this paper, we propose, model, and analyze the performance of a detector array for localizing far-field particle-emitting sources, which is inspired by but generalizes the compound eye of insects. The array consists of multiple eyelets, each having a conical module with a lens on its top and an inner subarray containing multiple particle detectors. Using a parametric measurement model introduced for the array in Part I, in this part we analytically and numerically analyze the statistical performance of the array. First, we compute the statistical Cramer-Rao bounds (CRBs) on the errors in estimating the direction of arrival of the incident particles; then we derive a lower bound on the mean-square angular error (MSAE) of source localization for any specific array configuration; thirdly, we consider two source-direction estimators, the maximum likelihood estimator (MLE) and the weighted direction estimator (WDE), and analyze their MSAE performance. In the numerical examples, we quantitatively compare the performance of the proposed array with the biological compound eye; show the array performance as a function of the array configuration variables; optimally design the array configuration; illustrate that the MLE asymptotically attains the performance bound, whereas the WDE is nearly optimal for sufficiently large SNR; and analyze the hardware efficiency by comparing the two MSAE bounds. Potential applications of this work include artificial vision in medicine or robotics, astronomy assisted, security, and particle communications.     

A Compact SPICE Model for Carbon-Nanotube Field-Effect Transistors Including Nonidealities and Its Application—Part II: Full Device Model and Circuit Performance Benchmarking

This paper presents a complete circuit-compatible compact model for single-walled carbon-nanotube field-effect transistors (CNFETs) as an extension to Part 1 of this two-part paper. For the first time, a universal circuit-compatible CNFET model including the practical device nonidealities is implemented with HSPICE. In addition to the nonidealities included in the companion paper, this paper includes the elastic scattering in the channel region, the resistive source/drain (S/D), the Schottky-barrier resistance, and the parasitic gate capacitances. More than one nanotube per device can be modeled. Compared to silicon technology, the CNFETs show much better device performance based on the intrinsic gate-delay metric (six times for nFET and 14 times for pFET) than the MOSFET device at the 32-nm node, even with device nonidealities. This large speed improvement is significantly degraded (by a factor of five to eight) by interconnect capacitance in a real circuit environment. We performed circuit-performance comparison with all the standard digital library cells between CMOS random logic and CNFET random logic with HSPICE simulation. Compared to CMOS circuits, the CNFET circuits with one to ten carbon nanotubes per device is about two to ten times faster, the energy consumption per cycle is about seven to two times lower, and the energy-delay product is about 15-20 times lower, considering the realistic layout pattern and the interconnect wiring capacitance.     

Capacity Analysis for Continuous Alphabet Channels With Side Information, Part II: MIMO Channels

In this second part of our two-part paper, we consider the capacity analysis for wireless mobile systems with multiple-antenna architectures. We apply the results of the first part to a commonly known baseband, discrete-time multiple-antenna system where both the transmitter and receiver know the channel's statistical law. We analyze the capacity for additive white Gaussian noise (AWGN) channels, fading channels with full channel state information (CSI) at the receiver, fading channels with no CSI, and fading channels with partial CSI at the receiver. For each type of channels, we study the capacity value as well as issues such as the existence, uniqueness, and characterization of the capacity-achieving measures for different types of moment constraints. The results are applicable to both Rayleigh and Rician fading channels in the presence of arbitrary line-of-sight and correlation profiles.     

Physical Modeling of Fast p-i-n Diodes With Carrier Lifetime Zoning, Part II: Parameter Extraction

In this paper, a parameter extraction procedure for high-voltage diodes with local lifetime control is proposed. It is designed for use with the physics-based diode model described in Part I, which is capable of simulating diodes with local lifetime control. The parameter extraction procedure described requires a forward characteristic and a reverse recovery measurement. The parameter extraction procedure is illustrated using finite-element simulations. The physics-based model using the parameters extracted is then compared with experimental results.     

Physical Modeling of Fast p-i-n Diodes With Carrier Lifetime Zoning, Part I: Device Model

This paper presents the development and implementation of a physics-based diode model which can simulate aspects of high-voltage diodes such as snappy recovery during punch-through and the modified carrier density profile due to local lifetime control. It uses a Fourier series solution for the ambipolar diffusion equation in the lightly doped base region. The model is compared with finite-element device simulations. A parameter extraction procedure for the diode with lifetime control is proposed in Part II.     

The COST 259 Directional Channel Model?Part II: Macrocells

This paper describes the attributes of the COST 259 directional channel model that are applicable for use in the design and implementation of macrocellular mobile and portable radio systems and associated technology. Special care has been taken to model all propagation mechanisms that are currently understood to contribute to the characteristics of practical macrocellular channels and confirm that large scale, small scale, and directional characteristics of implemented models are realistic through their comparison with available measured data. The model that is described makes full use of previously published work, as well as incorporating some new results. It is considered that its implementation should contribute to a too) that can be used for simulations and comparison of different aspects of a large variety of wireless communication systems, including those that exploit the spatial aspects of radio channels, as, for example, through the use of adaptive antenna systems     

PPNet：基于预先预测的降雨短时预测模型

降雨短时预测一直以来都是气象预测问题中的热点问题。传统的预测方法基于数值天气预测模型展开预报,但近些年利用深度学习展开基于雷达回波图的降雨短时预测方法受到了广大研究者的关注。其中,时序预测网络存在不能并行计算导致耗时过长的问题且存在梯度爆炸问题。全卷积网络可以解决上述两个问题,但是却不具备时序信息提取的能力。因此,该文以泰勒冻结假设为理论依据,提出一个基于预先预测辅助推断结构的2维全卷积网络(PPNet)。网络先行提取粗粒度时序信息与空间信息,然后利用全卷积结构细化特征粒度,有效缓解2维卷积网络不能提取时序信息的缺陷。此外,该文还提供一种时序特征约束器对预先预测特征进行时间维度的特征约束,使预测特征更倾向于真实特征。消融实验证明所提预先预测辅助推断结构和时序特征约束器具有优秀的时序特征能力,可以提升网络对时序信息的敏感度。与目前最好的降雨预测算法或视频预测算法相比,该文网络均取得较好结果,特别在暴雨指标上达到最优。     

Performance of MAP Reconstruction for Hot Lesion Detection in Whole-Body PET/CT: An Evaluation With Human and Numerical Observers

For positron emission tomography (PET) imaging, different reconstruction methods can be applied, including maximum likelihood (ML ) and maximum a posteriori (MAP) reconstruction. Postsmoothed ML images have approximately position and object independent spatial resolution, which is advantageous for (semi-) quantitative analysis. However, the complex object dependent smoothing obtained with MAP might yield improved noise characteristics, beneficial for lesion detection. In this contribution, MAP and postsmoothed ML are compared for hot spot detection by human observers and by the channelized Hotelling observer (CHO). The study design was based on the “multiple alternative forced choice” approach. For the MAP reconstruction, the relative difference prior was used. For postsmoothed ML, a Gaussian smoothing kernel was used. Both the human observers and the CHO performed slightly better on MAP images than on postsmoothed ML images. The average CHO performance was similar to the best human performance. The CHO was then applied to evaluate the performance of priors with reduced penalty for large differences. For these priors, a poorer detection performance was obtained.      

Performance Evaluation of Bluetooth Systems With LDI, Modified LDI, and NSD Receivers

Bluetooth is a popular short-range low-power radio standard for wireless personal area networks. Bluetooth transmitters employ Gaussian frequency shift keying (GFSK) and simple block codes for error correction. Recently, two new receiver designs for Bluetooth devices, which are the so-called modified limiter-discriminator detector with integrate-and-dump filtering (LDI) and noncoherent sequence detection (NSD), have been proposed in the literature. While the modified LDI receiver is a concatenation of a conventional LDI detector with an improved error-correction decoder, the NSD receiver fully takes into account the memory introduced by the GFSK. Both receivers have been shown to improve the Bluetooth system performance in terms of physical-layer metrics such as bit-error rate and packet-error rate. In this paper, we present a comprehensive performance evaluation considering practically more relevant metrics such as throughput, delay, and delay jitter at the medium-access control layer. To this end, we develop an evaluation framework, which includes the spatial distribution of Bluetooth devices, path loss, fading, realistic data traffic models, scheduling, automatic repeat request, and baseband packet selection. Our numerical and simulation results verify that the newly introduced Bluetooth receivers, especially NSD, offer a significant performance enhancement for Bluetooth systems in terms of practically relevant measures.     

A New WiMAX/Wi-Fi Interoperability Model and Its Performance Evaluation

In this paper, a new interoperability model for deployment of the emerging IEEE 802.16; WiMAX (World Wide Interoperability for Microwave Access) and a Wi-Fi (Wireless Fidelity), IEEE 802.11 based on Wireless LAN technology in a complementary way as a path to migration towards the upcoming fourth generation, is presented. The model allows for the integration of the two technologies, combining the benefits of both worlds for Non line-of-sight environments. The suggested scenario is to have a hotspot Wi-Fi or urban cell surrounded by a set of WiMAX (suburban) cells where users can have continuous connectivity in different propagation environments. If the C/I (Carrier-to-Interference) of a user is higher than a given threshold (say C/I $>$ G) then the user connects to the Wi-Fi cell otherwise the user is admitted to a WiMAX cell. In both cases, the user will have the best of the available access technology with an acceptable level of grade-of-service, i.e. $<$ 2 %, on move. The suggested model includes mixed services support i.e. voice, data and video with mobility, as well as scalability based on scalable orthogonal frequency division multiplexing adaptive bandwidth allocation. The scalability is applied on data connection, where ongoing data connection is asked to modify its transmission rate for the sake of handover calls. Numerical results from the evaluation of the interoperability model are given. The curves for average data rate, utilization, blocking probability, handover blocking probability, grade of service, and throughput demonstrate the effectiveness of the new deployment model.     

A Performance Evaluation of Resilient Server with a Self-Repair Network Model

Mobile Networks and Applications - One of the essential parts of the cloud infrastructure is a computer server. Therefore, we need to preserve the computer server from failure, such as hang, denial...     

A Novel Numerical Model for Simulating Three Dimensional MIMO Channels With Complex Antenna Arrays

We develop a novel three-dimensional (3D) numerical model for rigorously simulating mutual coupling effects on the channel capacity of the multiple input multiple output (MIMO) systems. In this model, the efficient integral equation method mutlilevel Green's function interpolation method (MLGFIM) is for the first time employed to calculate the input admittances and radiation patterns of the transmit and receive antennas of MIMOs. Comparing with the Method of Moments whose complexity is $O(N^{2})$ , MLGFIM has an efficiency of $O(Nlog N)$ and is suitable for efficiently solving antenna arrays problems. To accurately model the EM wave propagation, we 1) use the ray tracing method to obtain the multi-paths and 2) rigorously obtain the dyadic path loss factor model from which a novel stochastic path loss model that is flexible for both the environments with PEC walls and that with infinite thick lossless dielectric walls is devised. Using the proposed model, we successfully analyze mutual coupling effects on the 3D correlation of a 2-by-2 monopole array and the indoor channel capacity of a 20-by-20 planar array and a 20-by-20 icosahedron array. The numerical examples in this paper demonstrate the efficiency of our model for simulating the MIMO system with complex radiators.      

A Global Access Independent Billing Model: Users' Perspective

This paper presents a state-of-the-art for billing from users' perspective, considering the development taking place in wireless technology. Further, authors propose a novel method for a ``Global Access Independent Billing Model' for the success of present as well as future wireless communications services. The importance of billing for the success of any future wireless technology has to be placed at the sane level, if not higher, as that of defining application and services. This revised version was published online in August 2006 with corrections to the Cover Date.     

CEE-Gr:一个在多约束下进行性能优化的总体布线器

提出了一个在多约束下进行性能优化的总体布线算法.研究了在总体布线阶段同时进行RLC耦合噪声(串扰)、时延性能和布线拥挤优化的问题.根据所提出的算法思想已实现了相应的总体布线器:CEE-Gr.并对所实现的总体布线器CEE-Gr进行了MCNC电路例子的测试,得到令人满意的结果.     

Part II: A Novel Scheme to Optimize the Mixed-Signal Performance and Hot-carrier Reliability of Drain-Extended MOS Devices

The impact of scaling the depth of the shallow trench isolation (STI) region, underneath the gate-to-drain overlap, on the STI drain-extended metal–oxide–semiconductor (DeMOS) mixed-signal performance and hot-carrier behavior is systematically investigated in this work. For the first time, we discuss a dual-STI process for input/output applications. Furthermore, the differences in the hot-carrier behavior of various drain-extended devices are studied under the on- and off-states. We found that the non-STI DeMOS devices are quite prone to failure when compared with the STI DeMOS devices in both the on- and off- states. We introduced a more accurate way of predicting hot-carrier degradation in these types of devices in the on-state. We show that scaling the depth of the STI underneath the gate is the key for improving both the mixed-signal and hot-carrier reliability performances of these devices.      

CEE-Gr:一个在多约束下进行性能优化的总体布线器

提出了一个在多约束下进行性能优化的总体布线算法 .研究了在总体布线阶段同时进行 RL C耦合噪声 (串扰 )、时延性能和布线拥挤优化的问题 .根据所提出的算法思想已实现了相应的总体布线器 :CEE- Gr.并对所实现的总体布线器 CEE- Gr进行了 MCNC电路例子的测试 ,得到令人满意的结果.