Stability, Causality, and Passivity in Electrical Interconnect Models

Modern packaging design requires extensive signal integrity simulations in order to assess the electrical performance of the system. The feasibility of such simulations is granted only when accurate and efficient models are available for all system parts and components having a significant influence on the signals. Unfortunately, model derivation is still a challenging task, despite the extensive research that has been devoted to this topic. In fact, it is a common experience that modeling or simulation tasks sometimes fail, often without a clear understanding of the main reason. This paper presents the fundamental properties of causality, stability, and passivity that electrical interconnect models must satisfy in order to be physically consistent. All basic definitions are reviewed in time domain, Laplace domain, and frequency domain, and all significant interrelations between these properties are outlined. This background material is used to interpret several common situations where either model derivation or model use in a computer-aided design environment fails dramatically.We show that the root cause for these difficulties can always be traced back to the lack of stability, causality, or passivity in the data providing the structure characterization and/or in the model itsel

Performance Evaluation of AODV and DSR Routing Protocols in MANET Networks

Extensive use of wireless networks in different fields increases the need to improve their performance, as well as minimize the amplitude of loss messages. Device mobility, where there is no standard topology that can be applied or fixed routing that can be designed, is a topic that received recent attention in wireless networks. In a Mobile Ad Hoc Network (MANET), some nodes may join the network while others may leave. In this paper, we analyze a MANET’s performance for two proactive protocols; Ad Hoc On-Demand Distance Vector (AODV) Protocol, and Dynamic Source Routing (DSR) Protocol. By using network simulator NS2, we setup and evaluate the performance of AODV and DSR protocols with respect to the packets’size

Early Area and Power Estimation Model for Rapid System Level Design and Design Space Exploration

Power and area estimation in the early stage of designing is very critical for a system. This paper presents the neural network-based early area and power estimation model. The flow starts with the training of the neural network model from the selected behav- ioral level parameters, which imposes to provide ac- curate estimations. The model accuracy is validated against ITC99 benchmark programs. The run-times are faster than the synthesis run-times. For the ASIC- based designs, the proposed model took 5 seconds, while Synopsys Design Compiler took 5 minutes. In terms of timing, the estimation speed is more than the order of magnitude faster than the conventional synthesis- based approach. The modeling methodology provides a better, accurate, and fast area and power estima- tions, at an early stage of the Very-Large-Scale Integra- tion (VLSI) design. In addition, the model eliminates the need for synthesis-based exploration and provides the design picking before synthesis

A Practical Framework to Study Low-Power Scheduling Algorithms on Real-Time and Embedded Systems

With the advanced technology used to design VLSI (Very Large Scale Integration) circuits, low-power and energy-efficiency have played important roles for hardware and software implementation. Real-time scheduling is one of the fields that has attracted extensive attention to design low-power, embedded/real-time systems. The dynamic voltage scaling (DVS) and CPU shut-down are the two most popular techniques used to design the algorithms. In this paper, we firstly review the fundamental advances in the research of energy-efficient, real-time scheduling. Then, a unified framework with a real Intel PXA255 Xscale processor, namely real-energy, is designed, which can be used to measure the real performance of the algorithms. We conduct a case study to evaluate several classical algorithms by using the framework. The energy efficiency and the quantitative difference in their performance, as well as the practical issues found in the implementation of these algorithms are discussed. Our experiments show a gap between the theoretical and real results. Our framework not only gives researchers a tool to evaluate their system designs, but also helps them to bridge this gap in their future works

Simplified Motion Control of a Vehicle manipulator for the Coordinated Mobile Manipulation

This paper considers a resolved kinematic motion control approach for controlling a spatial serial manipulator arm that is mounted on a vehicle base. The end-effector’s motion of the manipulator is controlled by a novel kinematic control scheme, and the performance is compared with the well-known operational-space control scheme. The proposed control scheme aims to track the given operational-space (end-effector) motion trajectory with the help of resolved configuration-space motion without using the Jacobian matrix inverse or pseudo inverse. The experimental testing results show that the suggested control scheme is as close to the conventional operational-space kinematic control scheme

Querying for the Largest Empty Geometric Object in a Desired Location

We study new types of geometric query problems defined as follows: given a geometric set $P$, preprocess it such that given a query point $q$, the location of the largest circle that does not contain any member of $P$, but contains $q$ can be reported efficiently. The geometric sets we consider for $P$ are boundaries of convex and simple polygons, and point sets. While we primarily focus on circles as the desired shape, we also briefly discuss empty rectangles in the context of point sets.Comment: This version is a significant update of our earlier submission arXiv:1004.0558v1. Apart from new variants studied in Sections 3 and 4, the results have been improved in Section 5.Please note that the change in title and abstract indicate that we have expanded the scope of the problems we stud