Search results for " controller"
showing 10 items of 139 documents
Control of a non-isothermal continuous stirred tank reactor by a feedback–feedforward structure using type-2 fuzzy logic controllers
2011
A control system that uses type-2 fuzzy logic controllers (FLC) is proposed for the control of a non-isothermal continuous stirred tank reactor (CSTR), where a first order irreversible reaction occurs and that is characterized by the presence of bifurcations. Bifurcations due to parameter variations can bring the reactor to instability or create new working conditions which although stable are unacceptable. An extensive analysis of the uncontrolled CSTR dynamics was carried out and used for the choice of the control configuration and the development of controllers. In addition to a feedback controller, the introduction of a feedforward control loop was required to maintain effective control…
A design methodology for adaptive type-2 fuzzy controllers
2011
A genetic algorithm for the design of a fuzzy controller for active queue management
2003
Active queue management (AQM) policies are those\ud policies of router queue management that allow for the detection of network congestion, the notification of such occurrences to the\ud hosts on the network borders, and the adoption of a suitable control\ud policy. This paper proposes the adoption of a fuzzy proportional\ud integral (FPI) controller as an active queue manager for Internet\ud routers. The analytical design of the proposed FPI controller is\ud carried out in analogy with a proportional integral (PI) controller,\ud which recently has been proposed for AQM. A genetic algorithm is\ud proposed for tuning of the FPI controller parameters with respect\ud to optimal disturbance rej…
A new fuzzy logic controller for trading on the stock market
2007
A common problem that financia l operators often meet in their own work is to make, at the right moment, the operational choices on the Stock Market. Once the Market to act on has been chosen, the financial operator has to decide when and how to operate on it, in order to achieve a profit . The problem that we are going to deal with is the planning of an automatic decisional system for the management of long positions on bull market. First, a trading system (TS) will be im plemented pointing its features out. Then a fuzzy logic implementation of the TS will be introduced (FTS). The fuzzy system will be optimized by the genetic algorithms. Finally, the two different implementations of the tr…
On the Fidelity of IEEE 802.11 commercial cards
2006
The IEEE 802.11 D CF protocol is known to be fair in terms of long-term resource repartition among the contending stations. However, when considering real scenarios, where commercial 802.11 cards interact, very unpredictable as well as sometimes surprising behaviors emerge. Motivation of this paper is to investigate the reasons of the very evident disagreement between the theoretical IEEE 802.11 DCF protocol models and its practical implementations. Inparticular, we try to characterize the card behavior not only in terms of perceived throughput, but also in terms of low-level channel access operations. In fact, the simple throughput analysis does not allow to identify what affecting paramet…
Concepts, Theories, and Applications: The Role of “Experimentation” (and “Context”) for Formalizing New Ideas along Innovative Avenues
2012
The main aim of this paper is to present a few general ideas preliminary to an assessment of the role that a correct interchange between the elaboration of new theories and an open minded experimentation can have in the development of new fields of investigation. Although many of the reflections and remarks that follow will be of a very broad type, the reference background of all the paper will be, in general, the composite field of information sciences and, more specifically, the innovative concepts and approaches introduced by fuzzy sets theory. Abe Mamdani’s work can certainly be considered as an outstanding example of the way in which these innovations arose and, subsequently, flourishe…
Lone Star Stack: Architecture of a Disk-Based Archival System
2014
The need for huge storage systems rises with the ever growing creation of data. With growing capacities and shrinking prices, "write once read sometimes" workloads become more common. New data is constantly added, rarely updated or deleted, and every stored byte might be read at any time - a common pattern for digital archives or big data scenarios. We present the Lone Star Stack, a disk based archival storage system building block that is optimized for high reliability and energy efficiency. It provides a POSIX file system interface that uses flash based storage for write-offloading and metadata and the disk-based Lone Star RAID for user data storage. The RAID attempts to spin down disks a…
LoneStar RAID
2016
The need for huge storage archives rises with the ever growing creation of data. With today’s big data and data analytics applications, some of these huge archives become active in the sense that all stored data can be accessed at any time. Running and evolving these archives is a constant tradeoff between performance, capacity, and price. We present the LoneStar RAID, a disk-based storage architecture, which focuses on high reliability, low energy consumption, and cheap reads. It is designed for MAID systems with up to hundreds of disk drives per server and is optimized for “write once, read sometimes” workloads. We use dedicated data and parity disks, and export the data disks as individu…
Design of temperature control system using conventional PID and Intelligent Fuzzy Logic controller
2015
In this paper, we present the design of temperature control for industrial heat treating furnace by using Intelligent Fuzzy Logic and PID controllers. Temperature control is important in heating processes as it can disqualify materials in terms of their physical properties when not well performed. Obviously PID temperature controller is the most used in industries to control non-linear processes. Consequently, it has been found that the output response from Fuzzy Logic is very accurate in terms of overshoot and steady state error when compared to that of PID. Moreover, both temperature controllers are modeled and simulated using MATLAB software.
From UML Specification into FPGA Implementation
2014
In the paper a method of using the Unified Modeling Language for specification of digital systems, especially logic controllers, is presented. The proposed method is based mainly on the UML state machine di- agrams and uses Hierarchical Concurrent Finite State Machines (HCFSMs) as a temporary model. The paper shows a way to transform the UML diagrams, expressed in XML language, to the form that is acceptable by reconfigurable FPGAs (Field Programmable Gate Ar- rays). The UML specification is used to generate an eective program in Hardware Description Languages (HDLs), especially Verilog.