449 research outputs found

    Removal of malachite green oxalate from aqueous solution using sawdust as a biosorbent

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    Dyes are using in many industries such as textile, paper and ink, printing, pharmaceuticals, food industries…. They are highly visible contaminants and often toxic. Many dyes are stable to light and difficult to degrade, hence contaminants due to dyes pose to not only public health concern but also environmental problems. Due to the toxic nature of most dyes to human, plants and micro-organisms, colored waste water cannot be discharged without adequate treatment. Many methods to remove dye from industrial waste water are used such as biodegradation, coagulation-flocculation, adsorption, ozone treatment…. These methods are either not efficient or expensive. This study deals with low cost, locally available bio-sorbents. The literatures are reviewed using rich sources of information from library books, special journals and papers and internet. By studying the references, the methodology to study potential of using biosorbents to remove Malachite Green Oxalate has been come out. There are four main experiments will be conducted including factors influence dye biosorption, equilibrium test, kinetic study and effect of different forms of sorbent on biosorption of dye. The project can be the solution for current issue not only on colored waste water but also solid waste disposal. Since the bio-materials used are the waste from industries and agriculture. Furthermore, the result of this project can be used as reference for further study on biosorption using other types of biomaterial

    Fabrication of Twin-well CMOS

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    A single-mask self aligned Twin-well process has been integrated into RIT’s CMOS technology. These wells are self aligned to increase package density. The process has been simulated using TMA Suprem IV simulation tool. The simulated parameters were used in the actual fabrication. The wells are used to optimize both n- and p-channel active devices. The subthreshold leakage currents in isolated pmos and nmos devices are -1.28 pA.4/μn and 3.56 nA/μm of channel width, respectively when the devices were biased at \u3c 5 volts. In addition, the twinwell process has produced active n- and p-channel FET’s with excellent characteristics such as low threshold voltage, low subthreshold swing, and high transconductance

    Mixed-Criticality Scheduling on Multiprocessors using Task Grouping

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    Real-time systems are increasingly running a mix of tasks with different criticality levels: for instance, unmanned aerial vehicle has multiple software functions with different safety criticality levels, but runs them on a single, shared computational platform. In addition, these systems are increasingly deployed on multiprocessor platforms because this can help to reduce their cost, space, weight, and power consumption. To assure the safety of such systems, several mixed-criticality scheduling algorithms have been developed that can provide mixed-criticality timing guarantees. However, most existing algorithms have two important limitations: they do not guarantee strong isolation among the high-criticality tasks, and they offer poor real-time performance for the low-criticality tasks

    Partitioned Scheduling of Multi-Modal Mixed-Criticality Real-Time Systems on Multiprocessor Platforms

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    Real-time systems are becoming increasingly complex. A modern car, for example, requires a multitude of control tasks, such as braking, active suspension, and collision avoidance. These tasks not only exhibit different degrees of safety criticality but also change their criticalities as the driving mode changes. For instance, the suspension task is a critical part of the stability of the car at high speed, but it is only a comfort feature at low speed. Therefore, it is crucial to ensure timing guarantees for the system with respect to the tasks’ criticalities, not only within each mode but also during mode changes. This paper presents a partitioned multi-processor scheduling scheme for multi-modal mixed-criticality real-time systems. Our scheme consists of a packing algorithm and a scheduling algorithm for each processor that take into account both mode changes and criticalities. The packing algorithm maximizes the schedulable utilization across modes using the sustained criticality of each task, which captures the overall criticality of the task across modes. The scheduling algorithm combines Rate-Monotonic scheduling with a mode transition enforcement mechanism that relies on the transitional zero-slack instants of tasks to control low-criticality tasks during mode changes, so as to preserve the schedulability of high-criticality tasks. We also present an implementation of our scheduler in the Linux operating system, as well as an experimental evaluation to illustrate its practicality. Our evaluation shows that our scheme can provide close to twice as much tolerance to overloads (ductility) compared to a mode-agnostic scheme

    Compositional Analysis of Real-Time Embedded Systems

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    This tutorial is concerned with various aspects of component-based design and compositional analysis of real-time embedded systems. It will first give an overview of component-based frameworks and their underlying principles. It will then go in-depth into abstraction methods for real-time components and techniques for computing their optimal interfaces, for both systems implemented on uniprocessor and multiprocessor platforms, as well as extensions to multi-mode systems. Besides theoretical aspects, the tutorial will also present an implementation of the compositional analysis framework on Xen virtualization and a demonstration of the CARTS toolset with several examples seeing the techniques in action. It will also include two case studies highlighting the utility of the framework, including the ARINC-653 avionics software and a smart-phone application. We will conclude the tutorial with a number of open challenges and research opportunities in this domain

    NUMERICAL SIMULATION OF THE BULK FORMING PROCESS TO MANUFACTURE COUPLING DETAILS FROM TUBE BILLET

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    Currently, most coupling details in the actuators are made by traditional methods such as bulk forming from block billet and then metal cutting. Such manufacturing methods often lead to material wastes due to cutting a large amount of excess processing. To save material and improve production efficiency, tube billet would be selected for bulk forming. However, when tube billet is used for bulk forming, it should be carefully calculated to avoid instability and folding defects in workpiece. This article presents the research on the forming process of the coupling details using numerical simulation and based on the obtained results, the suitable geometric size of tube billet for the forming operation in closed die can be determined

    Cache-aware Interfaces for Compositional Real-Time Systems

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    Interface-based compositional analysis is by now a fairly established area of research in real-time systems. However, current research has not yet fully considered practical aspects, such as the effects of cache interferences on multicore platforms. This position paper discusses the analysis challenges and motivates the need for cache scheduling in this setting, and it highlights several research questions towards cache-aware interfaces for compositional systems on multicore platforms

    A Semantic Framework for Mode Change Protocols

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    We present a unified framework for the specification and analysis of mode-change protocols used in multi-mode realtime systems. We propose a highly expressive formalism, called MCP, to model the system behavior during mode transitions, and show how various existing mode change protocols can be described as MCPs. The explicit representation of the MCP model provides a means to analyze the system state during a mode transition as well as during an intra-mode execution. We introduce the concept of feasibility with respect to the MCP model, and give a decidable method for checking the feasibility of a MCP for a given multi-mode system. The formalization of mode change behaviors using the MCP model allows a range of mode change protocols to be modeled, evaluated, and optimized to the specific operations and performance requirements of the system. Besides feasibility analysis, it is also possible to analyze other system behaviors (e.g., delay between modes, buffer backlog) using automata verification techniques. Our framework can also be used to describe mode change semantics of multi-mode systems whose modes/transitions have different criticality levels, or of systems composed of multiple multi-mode components that require different mode change protocols

    日本研究の国際化及び学際化にむけて

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    世界の中の日本研究 : 批判的提言を求めて, 国際日本文化研究センター, 2018年5月19日-21

    Co-Design of Arbitrated Network Control Systems with Overrun Strategies

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    This paper addresses co-design of platform and control of multiple control applications in a network control system. Limited and shared resources among control and noncontrol applications introduce delays in transmitted messages. These delays in turn can degrade system performance and cause instabilities. In this paper, we propose an overrun framework together with a co-design to achieve both optimal control performance and efficient resource utilization. The starting point for this framework is an Arbitrated Network Control System (ANCS) approach, where flexibility and transparency in the network are utilized to arbitrate control messages. Using a two-parameter model for delays experienced by control messages that classifies them as nominal, medium, and large, we propose a controller that switches between nominal, skip and abort strategies. An automata-theoretic technique is introduced to derive analytical bounds on the abort and skip rates. A co-design algorithm is proposed to optimize the selection of the overrun parameters. A case study is presented that demonstrates the ANCS approach, the overrun framework and the overall co-design
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