Low Power Usage Research Articles

Fabry–Perot optical fiber strainmeter with an embeddable, low-power interrogation system

Detection of earthquakes and tidal variations via measurement of strain in the Earth’s crust requires compact and robust instrumentation with low power usage that can be deployed in the field. Here we demonstrate a stationary-wave integrated Fourier transform spectrometer (SWIFTS) and measure the variations induced by ground strain on an optical fiber Bragg grating sensor using two short (17±2 mm) Fabry–Perot (FP) cavities, one for the sensor, and one for temperature compensation. The SWIFTS delivers spatial interferograms that are then Fourier transformed to deduce the deformation from a cross-spectral analysis of the FP spectra. The full system is tested in field conditions to record crustal earth strain signals and successfully detect the earth tide and an earthquake signal. With this low-coherency interferometry technique, this system offers an excellent compromise between the resolution needed and the cost of a fully autonomous field instrument.

Development and application of a microfluidic in-situ analyzer for dissolved Fe and Mn in natural waters

The redox sensitive trace metals iron and manganese are two important elements that help shape the biogeochemistry of aquatic systems and thus their measurement is important. Current laboratory methods are expensive, time consuming and cannot provide the spatial and temporal resolution needed to characterize these elements in natural waters. Here we describe the first autonomous analyzer capable of providing vertical profiles as well as routine in-situ determinations of dissolved Fe(II) and Mn in aquatic environments. The spectrophotometric sensor uses microfluidic methods (Lab-on-a-chip technology) and mixes reagents and samples using a novel in-cell diffusion process. Fe(II) and Mn can be measured with a frequency of up to 12 and 6 samples per hour respectively with limits of detection of 27nM for Fe(II), 2.1% precision (n=20), and 28nM for Mn, 2.4% precision (n=19). The device combines relatively low cost, low power usage, low reagent consumption, portability, and tolerance to pressures up to at least 170 bars, with high precision and accuracy. We present data from a successful demonstration of the sensor during a cruise to the Gotland and Landsort Deep Basins of the Baltic Sea.

Conceptual design of a low-pressure micro-resistojet based on a sublimating solid propellant

Abstract In the current and future trend towards smaller satellite missions, the development of a simple and reliable propulsion system with performance and characteristics in line with the typical requirements of nano-satellites and CubeSats plays a crucial role for enhancing the capabilities of this type of missions. This paper describes the design of a micro-resistojet using water stored in the frozen state (ice) as propellant, operating under sublimation conditions at low pressure. The low operating pressure allows for using the vapor pressure of ice as the only method of propellant feeding, thereby allowing for extremely low thrust and electric power usage. The results of an extensive set of numerical simulations for optimizing the thruster geometry in terms of power ratio and specific impulse produced are discussed. In addition, the design of the complete propulsion system is described. It makes use of a limited number of moving parts and two power sources, one in the thruster to increase the propellant temperature and one in the tank to maintain the propellant storage conditions. Results show that the proposed design represents an alternative option capable of meeting the typical requirements of small satellite missions by means of an intrinsically green propellant such as water, with the pressure inside the system never exceeding 600 Pa. Optimization results showed an optimum thrust to power ratio in range 0.2–1.2 mN/W for an expansion slot aspect ratio of 2.5.

이종 네트워크에서의 비협력 게임 기반 전력 할당 기법

본 논문에서는 이종네트워크에서 펨토셀의 전력제어 기법을 게임이론을 이용해 정의한다. 저전력으로 고품질의 통신환경을 제공하는 펨토셀은 여러 장점으로 인해 최근 이슈화 되고 있지만 다수의 펨토셀 사용은 매크로셀과의 같은 채널을 사용함으로 인한 많은 량의 간섭으로 작용한다. 게임이론의 적용을 위해 셀룰러 네트워크의 기지국 및 사용자를 게임을 하는 플레이어로 설정하고 서로에게 미치는 간섭 영향을 전력 효용함수로 모델링 하였다. 또한 최적의 전력을 사용하여 시뮬레이션을 통한 저전력 사용, 간섭량 감소 그리고 시스템 전체 성능 향상을 확인하였다. We propose Femto-cell power control scheme in HeNet with Game Theory. The Femto-cell which provide high quality with low power is issued by many benefits, however there is a bunch of interferences when many Femto-cells use overlapped bandwidth with Macro-cell. We defined base station of cellular networks and mobile users as players of Game Theory, and configured interference effect among each other as power utility function. Futhermore, we showed enhanced overall system performance, lower power usage and interference decrease by using optimal power.

Microwave oven fabricated hybrid memristor devices for non-volatile memory storage

Novel hybrid non-volatile memories made using an ultra-fast microwave heating method are reported for the first time. The devices, consisting of aligned ZnO nanorods embedded in poly (methyl methacrylate), require no forming step and exhibit reliable and reproducible bipolar resistive switching at low voltages and with low power usage. We attribute these properties to a combination of the high aspect ratio of the nanorods and the polymeric hybrid structure of the device. The extremely easy, fast and low-cost solution based method of fabrication makes possible the simple and quick production of cheap memory cells.

English

The major design challenge of home automation is to choose best standard for controlling devices in existing home environments without any changes in infrastructure. In previous years Zigbee was the promising technology for home automation. But now a day‘s Enocean is the new standard which competes with Zigbee. The temperature of the house is hard and complex to understand since a lot of factors has to be considered. Furthermore, the quality of the house including temperature control not only affects the house performance it also affects the human comfort in their house. In this paper temperature of the house is controlled by using Zigbee and Enocean because of their some features like low cost, low power usage and mesh networking. The work presented here is to show how we can implement Zigbee and Enocean model by using Matlab/Simulink. Some parameters of these technologies are also compared such as: delay, energy per packet and received signal strength indicator (RSSI).

Bandwidth-Efficient Precoding Scheme for Downlink Smart Utility Networks

The emerging smart utility networks (SUN) provide two-way communications between smart meters and smart appliances for purpose of low power usage, low cost, and high reliability. This paper deals with a bandwidth-efficient communication method based on the hidden pilot-aided scheme using a precoder in downlink SUN suitable for high-rate multimedia applications. With the aid of the design of a precoder and a superimposed hidden pilot, it is possible to estimate the channel without loss of bandwidth. In the channel estimation procedure, the inevitable data interference, which degrades the performance of channel estimation, can be reduced by the precoder design with an iterative scheme. Computer simulations show that the proposed scheme outperforms the conventional method in terms of achievable data rate, especially when a large number of subcarriers are employed.

Low-bandwidth reflex-based control for lower power walking: 65 km on a single battery charge

No legged walking robot yet approaches the high reliability and the low power usage of a walking person, even on flat ground. Here we describe a simple robot which makes small progress towards that goal. Ranger is a knee-less four-legged ‘bipedal’ robot which is energetically and computationally autonomous, except for radio controlled steering. Ranger walked 65.2 km in 186,076 steps in about 31 h without being touched by a human with a total cost of transport [TCOT ≡ P/mgv ] of 0.28, similar to human’s TCOT of ≈ 0.3. The high reliability and low energy use were achieved by: (a) development of an accurate bench-test-based simulation; (b) development of an intuitively tuned nominal trajectory based on simple locomotion models; and (c) offline design of a simple reflex-based (that is, event-driven discrete feed-forward) stabilizing controller. Further, once we replaced the intuitively tuned nominal trajectory with a trajectory found from numerical optimization, but still using event-based control, we could further reduce the TCOT to 0.19. At TCOT = 0.19, the robot’s total power of 11.5 W is used by sensors, processors and communications (45%), motor dissipation (≈34%) and positive mechanical work (≈21%). Ranger’s reliability and low energy use suggests that simplified implementation of offline trajectory optimization, stabilized by a low-bandwidth reflex-based controller, might lead to the energy-effective reliable walking of more complex robots.

A large amount of idle capacity under rapid expansion: Policy analysis on the dilemma of wind power utilization in China

Abstract Wind power installation in China has increased rapidly since 2004. However, wind power usage remains relatively low resulting in a lot of idle capacity beginning in 2007. In this paper, we determine the main framework of China's current wind power policies and illustrate how these policies led to the rapid installation expansion accompanied by large idle capacity. Building on this, we explore how to alleviate the high installation low wind power usage conflict in China. We establish optimal models to (i) analyze wind power and power grid company behavior; (ii) demonstrate the impact of China's current policies on power and grid companies; and (iii) clarify the causes and mechanisms resulting in high growth and low wind power capacity usage. Our analysis shows that the incentive incompatibility of current policies, which enticed power companies to pursue installation expansion regardless of quality while inhibiting grid companies from improving connectivity, transmission and scheduling technology, is the primary cause for such large-scale idle capacity. The results of our study suggest that the fundamental way to scale up wind power utilization is to enhance policy incentive compatibility, which mainly includes (i) distributing revenues and diversifying risk fairly between power and grid companies; and (ii) motivating power companies to address demand fluctuation actively.

Real-Time Measurement of Eccentric Motion With Low-Cost Capacitive Sensor

In the operation of rotating machinery, the axial tilt of a rotor is an inevitable phenomenon and often as important as its radial error motion. The cylindrical capacitive sensors (CCSs) have been developed and applied to measure such kind of errors in the past two decades. Compared with other competing sensors, such as optical, inductive, and piezoresistive transducers, CCSs have many advantages, such as low cost and power usage, and good stability, resolution, and speed, etc. In this paper, a new approach that measures the eccentric motions of a hydraulic pump by using a CCS is presented. With this proposed method, the eccentric motion can be acquired in real time with a carrier signal by a circuit of low-cost capacitance-to-digital converter. The analytical results are compared and verified with experiments.

A STUDY OF ZIGBEE TECHNOLOGY

The zigbee communication is a communication technology to connect local wireless nodes and provides high stability and transfer rate due to data communication with low power. In the nodes away from coordinator in one PAN, the signal strength is weak causing the network a shortage of low performance and inefficient use of resources due to transferring delay and increasing delay time and thus cannot conduct seamless communication. This study suggests the grouping method, that makes it possible to perform wide range data transferring depending on the node signal strength in zigbee node and analyzes the suggested algorithm through simulation. Based on IEEE 802.15.4 Low Rate-Wireless Personal Area Network (LR-WPAN) standard, the Zigbee standard has been proposed to interconnect simple, low rate and battery powered wireless devices. The de-ployment of Zigbee networks is expected to facilitate numerous applications such as Home-appliance net-works, home healthcare, medical monitoring and environmental sensors. An effective routing scheme is more important for Zigbee mesh networks. In order to achieve effective routing in Zigbee Mesh networks, a Zigbee protocol module is realized using NS-2. The suitable routing for different data services in the Zigbee application layer and a best routing strategy for Zigbee mesh network are proposed. The ZigBee standard provides network, security, and application support services operating on top of the IEEE 802.15.4 Medium AccessControl (MAC) and Physical Layer wireless standard. It employs a group of technologies to enable scalable, self-organizing, self-healing networks that can manage various data traffic patterns. ZigBee is a low-cost, low-power, wireless mesh networking standard. The low costal lows the technologyto be widely deployed in wireless control and monitoring applications, the low power-usage allows longerlife with smaller batteries, and the mesh networking which promises high reliability and larger range. ZigBee has-been developed to meet the growing demand for capable wireless networking between numerous low power devices. The aims of this network are to reduce the energy consumption and latency by enhancing routing algorithm. In a traditional tree routing when a node wants to transmit a packet to the destination, the packet has to follow child/parent relationship and go along tree topology, even if the destination is lying at nearby source. In order to solve this problem, an Enhanced Tree Routing Algorithm is introduced using ZigBee network. This algorithm can find the shortest path by computing the routing cost for all of router that stored in neighbor table, and transmit the packet to the neighbor router that can reduce the hop count of transmission. The enhanced tree routing algorithm can achieve more stable and better efficiency then the previous traditional tree routing algorithm.

Watermarking Hardware Based on Wavelet Coefficients Quantization Method

Progress in the digital multimedia technologies during the last decade has offered many facilities in the transmission, reproduction, and manipulation of data. However, this advancement has also brought the problem such as copyright protection for content providers. Digital watermarking is a proposed solution for copyright protection for multimedia. The goal of hardware assisted watermarking is to achieve low power usage, real-time performance, reliability, and ease of integration with existing consumer electronic devices. An efficient architecture for transform domain watermarking using quantization approach is proposed here. This architecture is optimized using pipelining. The main objective of this paper is to propose a very-large-scale integration (VLSI) architecture for robust and blind image watermarking chip. Watermarking architectures with and without pipeline are synthesized using Xilinx’s ISE for a field-programmable gate array (FPGA), and then semi-custom integrated chip is designed using UMC 0.18 μm technology standard cell library for both these architectures. The proposed optimized pipelined watermarking encoder core requires 0.027 mm2 area and 0.074 mW power.

A Real-time BLE Enabled ECG System for Remote Monitoring

A major requirement of ubiquitous healthcare systems consists in the provision of low power usage, battery operated devices that are used in long term patient monitoring. Thus far, researchers have tried to adapt various short range technologies such as IEEE802.15.4, classical Bluetooth etc., to achieve this goal. The IEEE802.15.4 was, by excellence, widely deployed because of its low power and its security features compared to technologies such as the classical Bluetooth. However, the Bluetooth Special Interest group has recently announced Bluetooth 4.0 with low energy technology (BLE) for low power personal area networked devices, which offers more compelling features in various aspects when compared to IEEE802.15.4. This makes its evaluation for healthcare applications an urgently needed endeavour. In this paper, we present a BLE-based remote health monitoring system in which we have interfaced an ECG simulator directly to a BLE enabled CC2540 wireless sensor node (a system-on-chip (SoC) for Bluetooth low energy applications, from Texas Instruments). The node acts as a slave to the Master BLE device. In our system, we have used a BLE112 module (from Bluegiga) as a slave node while for the master we have used a BLE USB dongle connected to a PC in order to manage data received from the sensor node. A server application running on the PC uses a TCP-based connection over the network interface in order to enable remote monitoring. Any remote client can connect to the server and receives live updates from the sensor node. We have developed a LabVIEW based TCP client application to provide this functionality. An ECG simulator was used to generate ECG signals for different heartbeat rates that were sent through the BLE enabled network. The waveforms received at remote station using the developed system were found to conform exactly to those captured using a high resolution oscilloscope.

Implementation Analog Neural Network for Electronic Nose using Field Programable Analog Arrays (FPAA)

Electronic nose is a device detecting odors which is designed to resemble the ability of the human nose, usually applied to the robot. The process of identification of the electronic nose will run into a problem when the gas which is detected has the same chemical element. Misidentification due to the similarity of chemical properties of gases is possible; it can be solved using neural network algorithms. The attendance of Field Programmable Analog Array (FPAA) enables the design and implementation of an analog neural network, while the advantage of analog neural network which is an input signal from the sensor can be processed directly by the FPAA without having to be converted into a digital signal. Direct analog signal process can reduce errors due to conversion and speed up the computing process. The small size and low power usage of FPAA are very suitable when it is used for the implementation of the electronic nose that will be applied to the robot. From this study, it was shown that the implementation of analog neural network in FPAA can support the performance of electronic nose in terms of flexibility (resource component required), speed, and power consumption. To build an analog neural network with three input nodes and two output nodes only need two pieces of Configurable Analog Block (CAB), of the four provided by the FPAA. Analog neural network construction has a speed of the process 0.375 μs, and requires only 59 ± 18mW resources. DOI: http://dx.doi.org/10.11591/ijece.v2i6.1501

저전력 NAND 플래시 메모리를 위한 필터 버퍼의 효율성 분석

Currently, NAND Flash memory has been widely used in consumer storage devices due to its non-volatility, stability, economical feasibility, low power usage, durability, and high density. However, a high capacity of NAND flash memory causes the high power consumption and the low performance. In the convention memory research, a hierarchical filter mechanism can archive an effective performance improvement in terms of the power consumption. In order to attain the best filter structure for NAND flash memory, we selected a direct-mapped filter, a victim filter, a fully associative filter and a 4-way set associative filter for comparison in the performance analysis. According to the results of the simulation, the fully associative filter buffer with a 128byte fetching size can obtain the bet performance compared to another filter structures, and it can reduce the energy*delay product(EDP) by about 93% compared to the conventional NAND Flash memory.

Efficient MPEG-2 Transport Stream Encryption Method for Low Processing Power Mobile Devices

Video stream encryption is the main method for the protection of intellectual property in modern digital rights management systems (DRM). Existing encryption methods ensure very high protection level of encrypted content, but at the same time are very resources demanding, making them hardly suitable for low processing power mobile end-user devices. This paper presents partial MPEG-2 transport stream encryption method, which is suitable for such low power user terminals. The experimental evaluation of proposed method show that encryption and decryption times, comparing with standard full encryption, are reduced from 3 (static video) up to 9 times (dynamic video), making proposed method a good choice for low processing power decryption devices. Ill. 6, bibl. 14, tabl. 4 (in English; abstracts in English and Lithuanian). DOI: http://dx.doi.org/10.5755/j01.eee.118.2.1180

Qos Measurement of Zigbee Home Automation Network using Various Routing Protocols

In recent years, the home environment has seen a rapid increase in usage of network enabled digital technologies that offer new and exciting opportunities to increase the connectivity of devices within the home environment for the purpose of home automation. One of such digital technologies is known as ZigBee which is a recent wireless standard based on IEEE 802.15.4 used for Personal Area Networks. ZigBee is a low-cost, low-power, wireless mesh networking standard. The low cost allows the technology to be widely deployed in wireless control and monitoring applications, the low powerusage allows longer life with smaller batteries, and the mesh networking provides high reliability and larger range. This paper provides the performance analysis of different wireless mobile ad hoc routing protocols like OLSR INRIA, OLSRv2 NAGATA, ZRP, AODV and DYMO based on their effect on the quality of service by using CBR application in Zigbee home automation network using static IEEE 802.15.4. The QOS parameters such as data packet delivery ratio, average end-to-end delay, jitter, and throughput are investigated as the performance metrics. The results show that even though AODV gives the highest throughput of 95% and receive 25 packets which is highest amongst all five protocols but still overall OLSR INRIA is the best suited routing protocol for CBR application of Zigbee home automation since it produced lowest jitter value of 0.04 and lowest average endto-end delay value of 0.23 which are both favorable conditions for better performance of CBR application of Zigbee home automation network. General Terms IEEE802.15.4 (Zigbee) , WSN et al.

Repeater Coordination Using Optimism Algorithm

An optimization algorithm for repeater coordination is developed. Using a repeater with the system of CTCSS, much more low-power users can communicate with one another in situations where direct user-to-user contact would not be possible. Since the locations of these repeaters are arbitrary, the problem of repeater coordination in a circular flat area with minimum number of repeaters is difficult. But by using the completely seamless coverage theory and the hexagonal grid partition method, we can determine 14 optional repeater locations in two topological structures. Considering the necessary constraint conditions, we transfer this problem into the optimization planning problem.

New fully digital programmable gain amplifier scheme with reduced clipping noise for complementary metal oxide semiconductor image sensor

We propose a fully digital programmable gain amplifier scheme that overcomes the clipped noise analog-to-digital converter (ADC) for complementary metal-oxide semiconductor (CMOS) image sensors. Adopting the new digital programmable gain amplifier (DPGA) scheme, it obtains low noise and low power usage, has a small size, and high robust gain characteristic. To reduce the clipping noise, one new current controling the reference voltage of a 9-bit flash ADC is brought about in this work. Using the fully digital amplification scheme with reduced clipping noise ADC solves almost all the problems of the conventional analog programmable gain amplifier (APGA) scheme, which has large noise, large power, and big chip size due to APGA, and two analog autozero loop (both clamping circuit loop and offset correction loop) circuits. Based on a 0.18-µm CMOS image sensor process, one product of video graphic array (VGA) format CMOS image sensor is fabricated. The silicon test shows a 68-dB dynamic range with the power consumption of 80 mW at 24 MHz and the total noise of about 2 mV (at 30 fps and 27 deg).

Next Generation Spectrum Regulation for Europe: Price-Guided Radio Policy

This project examines how market signals in the form of pricing information can be introduced into spectrum management in order to optimally guide not only assignment, but also determinations concerning type of use, emissions characteristics and exclusivity. We construct a mathematical model to illuminate how one possible implementation of such price-guided policy might function to make these determinations. For the past nearly two decades, spectrum management authorities have used market mechanisms such as auctions to determine spectrum assignment in an effort to ensure that the right to utilize the spectrum is held by those who value it most. As compared to conventional spectrum auctions, price-guided policy for determining allocations would arrive at an assignment of spectrum rights to the highest value users as well as ensure that the contours of those rights were the most efficient possible. In the mathematical model presented in this paper, participants in a hypothetical auction are free to express their demand for spectrum licences which are different on several dimensions such as permissible power output and bandwidth. These demands are dictated by what is necessary to satisfy a specified a pre-specified level data rate using wireless communications ability. We use the Shannon Hartley Theorem to model the possible tradeoffs between permissible signal strength and allotted channel bandwidths. As a proof of concept of the mathematical model, we created a simplified MS Excel-based version of the model. The model’s output was also a mix of high and low power users, at various channel bandwidths and winning bids. We also review the implications of German Law and EU for such price-guided policy. Price-guided spectrum policy is viable in Europe. However, price-guided policies cannot be used to determine allocations and assignments in internationally harmonised bands. The most actionable initial implementations include determinations of maximum power limits, bandwidth, duration of rights and channelisation. Other early potential implementations include boundary interference standards and possibly congestion-based protocols.Price-guided policy holds substantial promise because it encourages allocative efficiency of spectrum due to the fact that bidders can acquire exactly the set of spectrum rights they need. Further, price-guided policy mitigates the allocation errors inherent in administrative determinations.