String Stability towards Leader thanks to Asymmetric Bidirectional Controller

This paper deals with the problem of string stability of interconnected systems with double-integrator open loop dynamics (e.g.~acceleration-controlled vehicles). We analyze an asymmetric bidirectional linear controller, where each vehicle is coupled solely to its immediate predecessor and to its immediate follower with different gains in these two directions. We show that in this setting, unlike with unidirectional or symmetric bidirectional controllers, string stability can be recovered when disturbances act only on a small ($N$-independent) set of leading vehicles. This improves existing results from the literature with this assumption. We also indicate that string stability with respect to arbitrarily distributed disturbances cannot be achieved with this controller.Comment: Version 2 corrects a typo in the proof, and adds the proof of stability before string stability. Slightly longer than published versio

On The Parallelization Of Integer Polynomial Multiplication

With the advent of hardware accelerator technologies, multi-core processors and GPUs, much effort for taking advantage of those architectures by designing parallel algorithms has been made. To achieve this goal, one needs to consider both algebraic complexity and parallelism, plus making efficient use of memory traffic, cache, and reducing overheads in the implementations. Polynomial multiplication is at the core of many algorithms in symbolic computation such as real root isolation which will be our main application for now. In this thesis, we first investigate the multiplication of dense univariate polynomials with integer coefficients targeting multi-core processors. Some of the proposed methods are based on well-known serial classical algorithms, whereas a novel algorithm is designed to make efficient use of the targeted hardware. Experimentation confirms our theoretical analysis. Second, we report on the first implementation of subproduct tree techniques on many-core architectures. These techniques are basically another application of polynomial multiplication, but over a prime field. This technique is used in multi-point evaluation and interpolation of polynomials with coefficients over a prime field

Translating Timing into an Architecture: The Synergy of COTSon and HLS (Domain Expertise—Designing a Computer Architecture via HLS)

Translating a system requirement into a low-level representation (e.g., register transfer level or RTL) is the typical goal of the design of FPGA-based systems. However, the Design Space Exploration (DSE) needed to identify the final architecture may be time consuming, even when using high-level synthesis (HLS) tools. In this article, we illustrate our hybrid methodology, which uses a frontend for HLS so that the DSE is performed more rapidly by using a higher level abstraction, but without losing accuracy, thanks to the HP-Labs COTSon simulation infrastructure in combination with our DSE tools (MYDSE tools). In particular, this proposed methodology proved useful to achieve an appropriate design of a whole system in a shorter time than trying to design everything directly in HLS. Our motivating problem was to deploy a novel execution model called data-flow threads (DF-Threads) running on yet-to-be-designed hardware. For that goal, directly using the HLS was too premature in the design cycle. Therefore, a key point of our methodology consists in defining the first prototype in our simulation framework and gradually migrating the design into the Xilinx HLS after validating the key performance metrics of our novel system in the simulator. To explain this workflow, we first use a simple driving example consisting in the modelling of a two-way associative cache. Then, we explain how we generalized this methodology and describe the types of results that we were able to analyze in the AXIOM project, which helped us reduce the development time from months/weeks to days/hours

Mobile phone social harms (mobile phone, communicative device or crime tool)

One of the human inventions created in order to facilitate life but it became scourge for him is mobile phone. Ignorance on quality of using mobile phone and conscious use of it in inappropriate way will have consequences that it seems that it gradually becomes as social problem and harm. Author of this paper aims to warns against risks and harmful and abnormal consequences of it since he believes that mobile will be a factor for crime as several crimes are occurring currently through this communicative tool that some of them will be discussed in this paper. Then, author has provided some recommendations at the end of paper in two sections related to government (three branches) and people (users). This study is a review paper in which data were collected by using library method and author has used of relevant papers, books, and reports.Keywords: mobile; social harm; crime; factors causing crime, other invention

Timing properties in real-time systems

This dissertation proposes a formalism for the specification and verification of timing properties of real-time systems. Reasoning about properties of a real-time system requires one to consider both relative and absolute timing of events. Relative timing concerns the order in which events occur, such as mutual exclusion and precedence constraint properties. Absolute timing concerns the stringent timing restrictions imposed on a system, such as a response time deadline or a minimum elapsed time between occurrences of two events. The approach is based on Real Time Logic (RTL), a logic invented primarily for the specification of both relative and absolute timing of events. The notion of an event occurrence is central to RTL; an event occurrence marks a point in time which is of significance to the behavior of a system. Hence, concurrency is modeled as a partial ordering of the event occurrences in the system. A system specification and a property to be verified can be expressed as arithmetical relations on algebraic expressions involving the event occurrences. To verify the property with respect to the system specification, we prove that the property is a theorem derivable from the specification. Relationship of RTL to Presburger Arithmetic is discussed and a verification technique based on inequality provers is explored. The dissertation also introduces a specification language, Modechart, for real-time systems. The semantics of Modechart is described in terms of RTL formulas. In Modechart, we make use of the concept of modes which can be thought of as partitioning the state space of a system. Intuitively, modes can be viewed as control information that impose structure on the operation of a system. Modes are arranged hierarchically. Furthermore, modes at the same level of hierarchy can be related in one of two ways: in series or in parallel. A transition can be specified between two modes in series, but no transition is allowed between modes in parallel. The language allows sporadic/periodic actions in modes as well as constructs for specifying timing constraints such as delays and deadlines on mode transitions. Verification procedures are introduced for showing a Modechart specification satisfies a property expressed as an RTL formula.Computer Science

Ordinary

In lieu of an abstract, below is the essay\u27s first paragraph. The water felt warm against her aching body. As she drew in a breath of jasmine and wildflowers, she laid her head back in the white bubbles that rested on the old ceramic of her bathtub. But the bubbles weren\u27t really white, she thought to herself, as she lifted a handful up to her face. They were really more like many multicolored transparent spheres that were so very delicate and full of beautiful fragrance. There were hues of pink and lavender and subtle hints of gold that would show when she turned her hand to the light, and this made her smile, because it was ordinary. The perfect spheres of color that disappeared as quickly as they formed, had made her long for ordinary times. And she almost wished she could become one of these bubbles, to float and glisten with color and then disappear with a hint of beauty. If only it could be that ordinary again