Energy efficiency is an important issue in computing systems and operating within a safe power budget is a necessary constraint. This paper presents a simple and practical solution both for energy ...minimization and peak power reduction, called Single Voltage Approximation (SVA) scheme, for periodic real-time tasks on multicore systems with a shared supply voltage in a voltage island. SVA is inspired by the Single Frequency Approximation (SFA) scheme, in which all the cores in the island run at a single voltage and frequency such that all tasks can meet their deadlines. In SVA, all the cores in the island are also executed at the same single voltage as in SFA. However, the frequency of each core is individually chosen, such that the tasks in each core can meet their deadlines, but without running at unnecessarily high frequencies. Thus, all the cores are executing tasks all the time and there is no need for any Dynamic Power Management (DPM) technique for reducing the energy consumption for idling. For task partitioning, SVA is combined with the Double Largest Task First (DLTF) partitioning scheme. Most importantly, this paper provides comprehensive analysis for combining DLTF and SVA, deriving its worst-case behavior both for energy minimization and peak power reduction, compared against the optimal solutions. Our analysis shows that, depending on the hardware, the energy consumption by combining DLTF and SVA is at most 1.95 (2.21, 2.42, and 2.59, respectively), compared to the optimal solutions, when the voltage island has up to 4 (8, 16, and 32, respectively) cores, which outperforms the worst-case factors of SFA when the cores fail to sleep efficiently. For peak power reduction, due to running at slower frequencies, combining DLTF and SVA always outperforms SFA, both in average and corner cases. Finally, we extend our analysis considering multicore systems with discrete voltage and frequency pairs and multiple voltage islands.
(1) Background: High-intensity interval training (HIIT) exerts effects indicative of improved health in young and older populations. However, prescribing analogous training programmes is ...inappropriate, as recovery from HIIT is different between young and older individuals. Sprint interval training (SIT) is a derivative of HIIT but with shorter, maximal effort intervals. Prior to prescribing this mode of training, it is imperative to understand the recovery period to prevent residual fatigue affecting subsequent adaptations. (2) Methods: Nine older (6M/3F; mean age of 70 ± 8 years) and nine young (6M/3F; mean age of 24 ± 3 years) participants performed a baseline peak power output (PPO) test. Subsequently, two SIT sessions consisting of three repetitions of 20 s 'all-out' stationary cycling bouts interspersed by 3 minutes of self-paced recovery were performed. SIT sessions were followed by 3 days' rest and 5 days' rest on two separate occasions, in a randomised crossover design. PPO was measured again to determine whether recovery had been achieved after 3 days or after 5 days. (3) Results: Two-way repeated measure (age (older, young) × 3 time (baseline, 3 days, 5 days)) ANOVA revealed a large effect of age (
= 0.002,
= 0.460), with older participants having a lower PPO compared to young participants. A small effect of time (
= 0.702,
= 0.022), and a medium interaction between age and time (
= 0.098,
= 0.135) was observed. (4) Conclusions: This study demonstrates both young and older adults recover PPO following 3 and 5 days' rest. As such, both groups could undertake SIT following three days of rest, without a reduction in PPO.
In this letter, we propose a new pulse position modulation (PPM) scheme, called expurgated PPM (EPPM), for application in peak power limited communication systems, such as impulse radio (IR) ultra ...wide band (UWB) systems and free space optical (FSO) communications. Using the proposed scheme, the constellation size and the bit-rate can be increased significantly in these systems. The symbols are obtained using symmetric balanced incomplete block designs (BIBD), forming a set of pair-wise equidistant symbols. The performance of Q-ary EPPM is better than any Q-ary pulse position-based modulation scheme with the same symbol length. Since the code is cyclic, the receiver for EPPM is simpler compared to multipulse PPM (MPPM).
AbstractBuildings are complex systems whose energy consumption depends on the interplay of multiple physical and human factors. This paper explored the performance of single-family detached dwellings ...using the tools of data analytics. The goals of this work were to understand and eventually to predict electrical energy consumption in order to develop strategies to reduce both peak power consumption and annual energy consumption in the residential building sector. Results showed that the year in which a dwelling was built combined with primary heating source is a significant predictor of electricity use.
The increasing demand of processing a higher number of applications and related data on computing platforms has resulted in reliance on multi-/many-core chips as they facilitate parallel processing. ...However, there is a desire for these platforms to be energy-efficient and reliable, and they need to perform secure computations for the interest of the whole community. This book provides perspectives on the aforementioned aspects from leading researchers in terms of state-of-the-art contributions and upcoming trends.
Accurate determination of the performance and precise prediction of the state of health (SOH) of lithium-ion batteries are necessary to ensure reliability and efficiency in real-world application. ...However, most SOH offline studies were based on dynamic stress tests, which only reflect the universal rule of degradation, but are not necessarily applicable for real-world applications. This paper presents an experimental evaluation of two different operations of real-world plug-in hybrid electric vehicles with LiFePO4 batteries as energy-storage systems. First, the LiFePO4 batteries were subjected to a set of comparative experimental tests that consider the effects of charge depleting (CD) and charge sustaining (CS) operations. Then, different voltage analysis along with the close-to-equilibrium open circle voltage was utilized to evaluate the performance of the batteries in life cycles. Finally, a qualitative relationship between the external factors (the percentage of time of CD/CS operations during the entire driving range) and the degradation mechanism was built with the help of the proposed methods. Results indicated that the external factors affect the degree of the batteries degradation, but not up to the point when the capacity fading stage occurs. This relationship contributes to the foundation for plug-in hybrid electric vehicles’ (PHEVs’) energy management strategy or battery management system control strategy.
In order to investigate the pulse modulation potential of SnSe2 in all-solid-state lasers, an active and passive dual-loss-modulated (APDM) Q-switched and mode-locking (QML) Nd:YVO4 laser was ...realized by employing an acousto-optic modulator (AOM) and a 5.9 nm thick SnSe2 saturable absorber (SA). The significant pulse compression ability of SnSe2 film was found experimentally, and sub-nanosecond mode-locking pulses with large peak power were obtained. The average output power, pulse energy, and pulse width versus the pump power were measured. With a pump power of 8.5 W, 242 ps mode-locking pulses with a pulse peak power of 231.4 kW were realized successfully. The experimental results also show that the SnSe2-based APDM QML laser has great potential in generating sub-nanosecond pulses with large peak power and high stability.
ABSTRACTIgnjatovic, AM, Markovic, ZM, and Radovanovic, DS. Effects of 12-week medicine ball training on muscle strength and power in young female handball players. J Strength Cond Res 26(8)2166–2173, ...2012—The purpose of this study was to examine the effects of medicine ball training on the strength and power in young female handball athletes. Twenty-one young female handball players (age, 16.9 ± 1.2 years) were randomly assigned to experimental and control groups. Experimental group (n = 11) participated in a 12-week medicine ball training program incorporated into the regular training session, whereas controls (n = 10) participated only in the regular training. Performance in the medicine ball throws in standing and sitting positions, 1 repetition maximum (1RM) bench and shoulder press, and power test at 2 different loads (30 and 50% of 1RM) on bench and shoulder press were assessed at pre- and posttraining testing. The athletes participating in the medicine ball training program made significantly greater gains in all medicine ball throw tests compared with the controls (p < 0.01). Also, the experimental group made significantly greater gains in bench and shoulder press power than control group (p < 0.05). Both training groups (E) and (C) significantly (p < 0.05) increased 1RM bench and shoulder strength, with no differences observed between the groups. Additionally, medicine ball throw tests showed stronger correlation with power tests, than with 1RM tests. These data suggest that 12-week medicine ball training, when incorporated into a regular training session, can provide greater sport-specific training improvements in the upper body for young female handball players.
PDF
