Greater Power Savings Research Articles

Energy efficient quality routing protocol for WSNs

Timely emerging research technology increases the need for real-time applications in Wireless Sensor Networks (WSN), which has made quality-based communication protocols an interesting and hot research topic. More specifically, network protocols must cope with power constraints while providing accurate quality assurance. In many of these applications, network traffic consists of delay-sensitive traffic and delay-tolerant traffic. Therefore, Quality of Service (QoS) routing becomes an important issue. The main purpose of this idea is to develop a way to improve the quality of the network and further improve throughput while at the same time creating an energy-saving method with excellent quality of service. This paper proposes to model an Energy Efficient Qualitative Routing Protocol (EEQRP) method based on an energy-efficient protocol that can be used to develop a fast, miniaturized, more energetic, and efficient way than existing routing protocols. It evaluates and compares the performance of the routing protocol (EEQRP). The Network Simulator-2 (NS2) is used to run and test the proposed system, which provides lower average latency, greater power savings, and a higher packet delivery rate than the current protocol.

Design of Low Power and High Speed 4X4 Multiplier using Modified Column Bypassing Scheme for DSP Applications

In this paper a low power and high speed 4X4 multiplier is designed using CMOS Technology. The important factors in VLSI Design are power, area, speed and design time. Now-a-days, power and speed has become a crucial factor in Digital Signal Processor (DSP) Applications. However, different optimization techniques are available in the digital electronic world. The proposed approach a Low power and high speed Multiplier Design based on Modified Column bypassing technique mainly used to reduce the switching power activity. While this technique offers great dynamic power savings, due to their interconnection. In this work, a low power and high speed multiplier with Hybridization scheme is presented. This scheme is combination of booth encoder algorithm and column bypass technique is called modified column bypassing scheme. The simulations are performed in 0.18µm CMOS Technology in Cadence Virtuoso tools with operating voltage ±1.8v

Adaptive dynamic voltage transitioning in switch mode DC–DC power converters

Higher transistor density in modern processors leads to an increase in computing power, which results in higher power consumption. To combat this, system-level power saving features like dynamic voltage transitions (DVTs) are introduced where the voltage required by the processor is varied according to computational load. In commercially available systems, the slew rate of the voltage transition is limited, which has the negative effect of increasing computational latency to ensure safe operation of the switch mode power converter. This study addresses the limitations of the existing techniques by introducing an adaptive DVT, which enables finer granularity of the operating voltage levels and promotes greater power savings. The switching surface-based analysis is performed to derive the conditions for (near) optimal voltage transitions constrained by inductor saturation limits. The results of an experimental prototype achieving the fastest safe transition response are shown to correlate well with the analysis across a wide range of DVT conditions.

A finite element based data analytics approach for modeling turning process of Inconel 718 alloys

Turning is a primary metal cutting process deployed extensively for producing components to required shape and dimensions. A commonly used material is Inconel 718, which exhibits an inferior economic feasibility in terms of turning due to its poor machinability characteristics. A combined finite element based data analytics model is introduced in this work. Finite element modeling was used to predict the cutting force while Genetic Programming was used to obtain the mathematical relation between the process variables and the cutting force. The weighted parameter analysis was conducted on the mathematical model which revealed that depth of cut and cutting angle exerts significant influence on the cutting force. As turning process is generally specified by a given depth of cut which dictates the material removal rate, optimization of tool cutting angle can result in enhanced power savings. It is anticipated that the findings obtained from this study can result in greater power savings in turning process of hard-to-machine materials which can lead to a sustainable manufacturing process.

Performance-controlled server consolidation for virtualized data centers with multi-tier applications

Modern data centers must provide performance assurance for complex system software such as multi-tier web applications. In addition, the power consumption of data centers needs to be minimized to reduce operating costs and avoid system overheating. Various power-efficient performance management strategies have been proposed based on dynamic voltage and frequency scaling (DVFS). Virtualization technologies have also made it possible to consolidate multiple virtual machines (VMs) onto a smaller number of active physical servers for even greater power savings, but at the cost of a higher overhead. This paper proposes a performance-controlled power optimization solution for virtualized server clusters with multi-tier applications. While most existing work relies on either DVFS or server consolidation in a separate manner, our solution utilizes both strategies for maximized power savings by integrating feedback control with optimization strategies. At the application level, a novel multi-input–multi-output controller is designed to achieve the desired performance for applications spanning multiple VMs, on a short time scale, by reallocating the CPU resources and conducting DVFS. At the cluster level, a power optimizer is proposed to incrementally consolidate VMs onto the most power-efficient servers on a longer time scale. Empirical results on a hardware testbed demonstrate that our solution outperforms pMapper, a state-of-the-art server consolidation algorithm, by having greater power savings and smaller consolidation overheads while achieving the required application performance. Extensive simulation results, based on a trace file of 5415 real servers, demonstrate the efficacy of our solution in large-scale data centers.

Fast Route Convergence in Dynamic Power Controlled Routing for Wireless Ad-hoc Networks

Previous work in wireless ad-hoc network routing has given rise to dynamic power controlled routing, which in turn enables variable-range transmissions. However, one limitation found in such protocols is the inclusion of at most one redirector in the route at each iteration. The work presented here introduces a redirector discovery algorithm which reaches the final route in less iterations, by including the possibility of adding two redirectors in each iterations. With this faster route convergence, greater power savings may be achieved, with the corresponding advantages this brings.

Nanosatellite swarm missions in low Earth orbit using laser propulsion

Many missions could benefit from the exploitation of very low height orbits, including Earth observation, atmospheric measurement and space weather research missions. However satelliteʼs lifetime decreases very quickly when the mission requires to orbit into the dense layers of the atmosphere. The mission performance could be enhanced using innovative propulsion techniques, counteracting the effect of atmospheric drag. Among these, laser propulsion potentially offers great weight and power savings, obtained by separating the propulsion system energy source from the propelled satellite. The energy source for the propulsion system is a pulsed laser beam generated remotely, while only collecting mirrors and ablative material are necessary on the target spacecraft. A mission architecture for very low altitude nanosatellite swarms using a space-based pulsed laser propulsion is described. A simplified laser-sustained re-orbiting maneuver sequence is proposed, leading to a straightforward evaluation of the maneuver times, showing that the laser propulsion system is suitable for low altitude nanosatellite missions.

Improving Energy Efficiency in Upstream EPON Channels by Packet Coalescing

In this paper, we research the feasibility of adapting the packet coalescing algorithm, used successfully in IEEE 802.3az Ethernet cards, to upstream EPON channels. Our simulation experiments show that, using this algorithm, great power savings are feasible without requiring any changes to the deployed access network infrastructure nor to protocols.

Opportunistic power saving algorithms for Ethernet devices

Network interfaces in most wired or wireless computing devices are greatly under-utilized, squandering energy while waiting for new packets to arrive. In this paper, we propose simple opportunistic algorithms to determine when to power down idle network interfaces in order to save much of that wasted energy. We also develop an analytic model to predict the amount of energy saved and the packet delay. The algorithms are compared to the best known opportunistic method, and it is shown that they provide significantly greater power savings without inflicting noticeable delays to Internet traffic.

THE EFFECTS OF COMPRESSION ON ULTRA WIDEBAND RADAR SIGNALS

Over the past ten years, Ultra Wideband (UWB) Radar has been widely investigated as a biomedical imaging modality, used to detect early-stage breast cancer and to continuously monitor vital signs using both wearable and contactless devices. The advantages of the technology in terms of low-power requirements and non-ionising radiation are well recognised, with the technology being applied to a range of non-invasive medical applications, from respiration to heart monitoring. Across all these applications, there is a strong necessity to e-ciently manage the large quantities of UWB data which will be captured. For wearable devices in particular, the e-cient compression of UWB data allows the monitoring system to conserve limited resources such as memory and battery capacity, by reducing data storage and in some cases transmission requirements. In contrast to lossless compression techniques, lossy compression algorithms can achieve higher compression ratios and consequently greater power savings, at the expense of a marginal degradation of the reconstructed signal. This paper compares the lossy JPEG2000 and Set Partitioning In Hierarchical Trees (SPIHT) algorithms for UWB signal compression. This study examines the efiects of lossy signal compression on an UWB breast cancer classiflcation algorithm. This particular application was chosen because the classiflcation algorithm relies heavily on shape and surface texture detail embedded in the Radar Target Signature (RTS) of the tumour, and therefore will provide both a robust and easily quantiflable test platform for the compression algorithms. The

Power efficient packet classification using cascaded bloom filter and off-the-shelf ternary CAM for WDM networks

In wavelength division multiplexing (WDM) networks, tens or hundreds of wavelengths can be transmitted over a single fiber. As transmission line speed goes to 10 Gb/s and beyond, ternary CAM (TCAM) is usually employed for wire speed packet classification. To the best of authors’ knowledge, this is the first paper that addresses the impact of WDM transmission on the power consumption of packet classification. We show that as the number of wavelengths increases in the WDM networks, the power consumption of TCAMs can become the limiting factor for WDM network expansion. For example, the power consumption of IPv4 and IPv6 packet classification with merely 32 channels at 40 Gb/s can be as high as 700 and 1400 W, respectively, while technology wise it is feasible to transmit over 500 channels over a single fiber. Existing power efficient TCAM designs require special modification to TCAM cell structures, which makes the adoption of the technology difficult. This paper proposes a novel approach which cascades bloom filter with off-the-shelf TCAM to greatly reduce the power consumption of packet classification. In particular, the proposed solution takes advantage of the fact that bloom filters may give false positive alarms but never give false negative alarms. By eliminating majority of non-matching packets before passing the packets to the TCAM, the TCAM is only activated to exam packets with a high potential of matching in the filter set. The proposed scheme greatly reduces the activation frequency of the TCAM, thus achieving great power savings.

Analysis of resonances during microwave thawing of slabs

Resonances or maxima in power absorption due to microwaves incidence within a slab are analyzed via transmitted and reflected waves. A generalized mathematical formulation for uniform plane waves has been established to analyze traveling waves, stationary waves and microwave power absorption within a multiphase sample. Preliminary studies based on the generalized mathematical analysis in ice and water slabs illustrate that greater amplitudes of traveling and stationary waves occur within ice samples, whereas, greater intensity of spatial resonances in microwave power occurs for water samples due to a greater dielectric loss of water. Microwave thawing is studied for specific sample thicknesses which are selected based on greater power distribution within water samples. The enthalpy method is employed for modeling of thawing of ice samples where a superficial mushy region is assumed around the melting point. Depending on the sample thickness, thawing may occur from the unexposed face as well as both the faces when the sample is exposed to microwaves at one face only, whereas thawing may originate from both the center as well as the faces when the sample is exposed to microwaves at both faces. Our analysis based on the generalized mathematical formulation validates the local maxima in spatial power distribution during intermediate thawing stages obtained with the finite element based enthalpy formulation. The generalized mathematical analysis on multiple thawed regimes further illustrates the role of traveling waves on resonances in microwave power. The influence of resonance is attributed by a non-monotonic variation of thawing time with sample thicknesses either for one side incidence or both side incidence due to microwaves. Optimal thawing strategies are recommended based on greater power savings.