58,670 research outputs found

    Implementation of sequential design based water level monitoring and controlling system

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    In currently decades, water usage either for domestic or commercial purposes is facing critical conditions which negatively affects the sustainability of our environment. From this point of view, reducing water consumptions will participate in the solution of water saving. Monitoring and controlling the tank water level are important functions which effect and work on reduction of water consumption.  Many studies in literature focus on proposing a high performance water level monitoring and controlling systems based on either computerized units or microcontroller units. However these systems are characterized by complexity and high cost. In this paper, a highly flexible implemented electronic system is introduced based on sequential design by using general purpose discrete components. The proposed system present simple design of water level sensing stage, in addition, this paper showing full design, simulation, and implementation steps of an automation system which is able to control switching the state of the water pump in accordance to the current level of water in the tank

    Low Power Processor Architectures and Contemporary Techniques for Power Optimization – A Review

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    The technological evolution has increased the number of transistors for a given die area significantly and increased the switching speed from few MHz to GHz range. Such inversely proportional decline in size and boost in performance consequently demands shrinking of supply voltage and effective power dissipation in chips with millions of transistors. This has triggered substantial amount of research in power reduction techniques into almost every aspect of the chip and particularly the processor cores contained in the chip. This paper presents an overview of techniques for achieving the power efficiency mainly at the processor core level but also visits related domains such as buses and memories. There are various processor parameters and features such as supply voltage, clock frequency, cache and pipelining which can be optimized to reduce the power consumption of the processor. This paper discusses various ways in which these parameters can be optimized. Also, emerging power efficient processor architectures are overviewed and research activities are discussed which should help reader identify how these factors in a processor contribute to power consumption. Some of these concepts have been already established whereas others are still active research areas. © 2009 ACADEMY PUBLISHER

    A survey of dynamic power optimization techniques

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    One of the most important considerations for the current VLSI/SOC design is power, which can be classified into power analysis and optimization. In this survey, the main concepts of power optimization including the sources and policies are introduced. Among the various approaches, dynamic power management (DPM), which implies to change devices states when they are not working at the highest speed or at their full capacity, is the most efficient one. Our explanations accompanying the figures specify the abstract concepts of DPM. This paper briefly surveys both heuristic and stochastic policies and discusses their advantages and disadvantages

    Development of Power Semiconductor Devices Database for Knowledge-Based Systems

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    Since 1970, various types of power semiconductor devices have been developed and become commercially available. Meanwhile database management and expert systems have been used in the field of power electronics for various applications. The large available number of power semiconductor devices makes it difficult to compare their numerical ratings such as voltage, current ratings and switching frequency. The objective of this thesis is to develop a database system for the power semiconductor devices in order to build the power electronics design aided system (PEDAS). PEDAS is a knowledge-based system for power electronic circuits that enable the user to get a suitable solution for the design problem through an attractive interface. The devices database system is an important and essential part of PEDAS. Using the devices database system, the user is able to get the suitable device available in the PSPICE simulation package and use its model for the design problem through a simple and attractive interface. The user can also get a comprehensive information about most of the power semiconductor devices commercially available by accessing the devices data sheets. A three-phase inverter was designed and simulated to illustrate the use of the devices database system. The inverter was designed using 1800 and 1200 conduction angle. 5kW-output power was achieved using 120V DC voltage source. The devices database system was used successfully by some of the researchers of the electrical engineering department in the Control and Automation System Centre (CASC)

    The physicochemical and antioxidant properties of double-boiled kelulut honey

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    Kelulut honey is a unique Malaysian food that has beneficial components and high potential in many health aspects. In commercial processing plant, honey is usually subjected to thermal treatment, where its quality is compromised due to unstable and thermolabile components. Therefore, double boiling was chosen as it does not exert significant heat, thus minimizes damage done. The quality was determined after treated by double boiling technique at optimized condition. Three different sources of Kelulut honey based on the main types of foods consumed by the bees (Coconut, Multifloral and Wild Flowers) were tested. Kelulut honey samples were subjected to an optimized condition at 60 °C for 35 minutes. Thermal treatment at the same condition was conducted for comparison purpose. The results showed that double boiling treatment increased the total phenolic content of Kelulut-C honey significantly, from 2430.78 ± 12.24 to 2711.10 ± 23.00 mg GAE/100 g. The treatment also significantly increased the brown pigment for both Kelulut-C and Kelulut-W honey by 11.11 ± 0.00% and 27.27 ± 0.00%, respectively. Whereas, the pH and moisture content of all samples remain unchanged with no formation of hydroxymethylfurfural (HMF) was observed. A preliminary four-week storage study showed that double boiling treatment improves physicochemical properties of Kelulut honey as compared to the untreated samples for all three types of Kelulut honey tested. Meanwhile, a room temperature (27 °C) condition leads to an improvement of antioxidant properties as compared to cold temperature (4 °C). In conclusion, double boiling treatment has established itself as a good alternative processing method for Kelulut honey, hence increasing the possibility to bring forward Kelulut honey as a unique source for the application in food and beverages industries

    Distribution automation applications of fiber optics

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    Motivations for interest and research in distribution automation are discussed. The communication requirements of distribution automation are examined and shown to exceed the capabilities of power line carrier, radio, and telephone systems. A fiber optic based communication system is described that is co-located with the distribution system and that could satisfy the data rate and reliability requirements. A cost comparison shows that it could be constructed at a cost that is similar to that of a power line carrier system. The requirements for fiber optic sensors for distribution automation are discussed. The design of a data link suitable for optically-powered electronic sensing is presented. Empirical results are given. A modeling technique that was used to understand the reflections of guided light from a variety of surfaces is described. An optical position-indicator design is discussed. Systems aspects of distribution automation are discussed, in particular, the lack of interface, communications, and data standards. The economics of distribution automation are examined
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