Effects of Continuous vs Discrete Frequency Scaling and Core Allocation on Energy Efficiency of Static Schedules for Moldable Tasks

Models for energy-efficient static scheduling of parallelizable tasks with deadlines on frequency-scalable parallel machines comprise moldable vs. malleable tasks and continuous vs. discrete frequency levels, plus preemptive vs. non-preemptive task execution with or without task migration. We investigate the tradeoff between scheduling time and energy efficiency when going from continuous to discrete core allocation and frequency levels on a multicore processor, and from preemptive to non-preemptive task execution. To this end, we present a tool to convert a schedule computed for malleable tasks on machines with continuous frequency scaling [Sanders and Speck, Euro-Par (2012)] into one for moldable tasks on a machine with discrete frequency levels. We compare the energy efficiency of the converted schedule to the energy consumed by a schedule produced by the integrated crown scheduler [Melot et al., ACM TACO (2015)] for moldable tasks and a machine with discrete frequency levels. Our experiments with synthetic and application-based task sets indicate that the converted Sanders Speck schedules, while computed faster, consume more energy on average than crown schedules. Surprisingly, it is not the step from malleable to moldable tasks that is responsible but the step from continuous to discrete frequency levels. One-time frequency scaling during a task’s execution can compensate for most of the energy overhead caused by frequency discretization.

Analyzing the Intrinsic Magnetic Field in the Galactic Center Radio Arc

The Radio Arc is a system of organized nonthermal filaments (NTFs) located within the Galactic center (GC) region of the Milky Way. Recent observations of the Radio Arc NTFs revealed a magnetic field that alternates between being parallel and rotated with respect to the orientation of the filaments. This pattern is in stark contrast to the predominantly parallel magnetic field orientations observed in other GC NTFs. To help elucidate the origin of this pattern, we analyze spectro-polarimetric data of the Radio Arc NTFs using an Australian Telescope Compact Array data set covering the continuous frequency range from ∼4 to 11 GHz at a spectral resolution of 2 MHz. We fit depolarization models to the spectral polarization data to characterize Faraday effects along the line of sight. We assess whether structures local to the Radio Arc NTFs may contribute to the unusual magnetic field orientation. External Faraday effects are identified as the most likely origin of the rotation observed for the Radio Arc NTFs; however, internal Faraday effects are also found to be likely in regions of parallel magnetic field. The increased likelihood of internal Faraday effects in parallel magnetic field regions may be attributed to the effects of structures local to the GC. One such structure could be the Radio Shell local to the Radio Arc NTFs. Future studies are needed to determine whether this alternating magnetic field pattern is present in other multi-stranded NTFs, or is a unique property resulting from the complex interstellar region local to the Radio Arc NTFs.

Topological protection of continuous frequency entangled biphoton states

Topological quantum optics that manipulates the topological protection of quantum states has attracted special interests in recent years. Here we demonstrate valley photonic crystals implementing topologically protected transport of the continuous frequency entangled biphoton states. We numerically simulate the nonlinear four-wave mixing interaction of topological valley kink states propagating along the interface between two valley photonic crystals. We theoretically clarify that the signal and idler photons generated from the four-wave mixing interaction are continuous frequency entangled. The numerical simulation results imply that the entangled biphoton states are robust against the sharp bends and scattering, giving clear evidence of topological protection of entangled photon pairs. Our proposal paves a concrete way to perform topological protection of entangled quantum states operating at telecommunication wavelengths.

Continuous and Discrete Spectra

This chapter explores the spectra of audio signals first from a continuous time and continuous frequency perspective. It starts by reviewing Fourier's theorem and then moves on to put it into its most general form, the Fourier transform. The spectra of simple signals are explored and determined. The operation of convolution is introduced, and through its discrete form, it is applied to the concepts of spectrum and waveform as mediated by the Fourier transform. The chapter is completed with a study of the discrete spectra of classic synthesis waveforms. A revised notion of spectrum is presented at the conclusion.

Pemodelan Klaster Frekuensi Suara Bising Mesin Pesawat Menggunakan Metode Extended Kalman Filter

Kebisingan adalah bunyi yang tidak diinginkan dari usaha atau kegiatan dalam tingkat dan waktu tertentu yang dapat menimbulkan gangguan kesehatan manusia dan kenyamanan lingkungan. Salah satunya kebisingan pada wilayah bandara yang terpancar dari gelombang suara mesin pesawat udara dan dapat mengganggu lingkungan. Menurut World Health Organization (WHO) suara bising sekeras 85 dB hanya dapat didengar secara terus menerus maksimal selama 8 jam per-hari. Setiap peningkatan suara bising sebesar 3 dB maka suara bising bertambah dua kali lipat. Suara bising dapat menjadi salah satu penyebab gangguan pendengaran (Noise Induced Hearing Loss). Penelitian ini menyajikan perencanaan mekanisme identifikasi sistem yang mencakup perencanaan skema identifikasi, pembentukan pasangan data identifikasi, dan penurunan algoritme identifikasi. Metode Extended Kalman Filter digunakan dalam mekanisme identifikasi untuk menemukan model hubungan antara komponen dominan pembentuk suara bising dengan suara bising secara keseluruhan yang kemudian dilakukan validasi terhadap model tersebut. Pengujian terhadap model dilakukan menggunakan sinyal-sinyal hasil pengukuran yang tidak diikutsertakan selama proses identifikasi. Hasil dari penelitian ini diperoleh bahwa frekuensi noise saat pesawat tinggal landas berkisar antara 50 Hz – 7000 Hz dengan model matematis spreaded continuous frequency.

Effect of Coverage on Adsorptions of CO on Ni(110) Surface

The adsorptions of CO on Ni(110) surface at different coverages have been investigated by first-principle calculations. The results show that CO will be bonded at short bridge site preferentially. And CO preferentially absorbs upright at short bridge sites and top sites at 1/6 monolayer coverage. With increasing coverage to 0.5 ML, the enhanced steric repulsion leads to the slope of CO. For 1/6 and 1/2 monolayer coverage, CO is mainly bonded at short bridge site and atop site simultaneously at a certain ratio. When CO coverage is 1 monolayer, CO absorbs at short bridge site and forms p2mg configuration. As the coverage of CO is increased to finally form the p2mg structure, there is a continuous frequency shift up to the value 1962.27 cm-1. The vibration frequencies we calculated are consistent with relative experimental results. DOS of CO molecules and Ni atoms are discussed too.

The Relative Weight of Temporal Envelope Cues in Different Frequency Regions for Mandarin Disyllabic Word Recognition

ObjectivesAcoustic temporal envelope (E) cues containing speech information are distributed across all frequency spectra. To provide a theoretical basis for the signal coding of hearing devices, we examined the relative weight of E cues in different frequency regions for Mandarin disyllabic word recognition in quiet.DesignE cues were extracted from 30 continuous frequency bands within the range of 80 to 7,562 Hz using Hilbert decomposition and assigned to five frequency regions from low to high. Disyllabic word recognition of 20 normal-hearing participants were obtained using the E cues available in two, three, or four frequency regions. The relative weights of the five frequency regions were calculated using least-squares approach.ResultsParticipants correctly identified 3.13–38.13%, 27.50–83.13%, or 75.00–93.13% of words when presented with two, three, or four frequency regions, respectively. Increasing the number of frequency region combinations improved recognition scores and decreased the magnitude of the differences in scores between combinations. This suggested a synergistic effect among E cues from different frequency regions. The mean weights of E cues of frequency regions 1–5 were 0.31, 0.19, 0.26, 0.22, and 0.02, respectively.ConclusionFor Mandarin disyllabic words, E cues of frequency regions 1 (80–502 Hz) and 3 (1,022–1,913 Hz) contributed more to word recognition than other regions, while frequency region 5 (3,856–7,562) contributed little.

Optimization of a type of elastic metamaterial for broadband wave suppression

The optimal design is studied for a type of one-dimensional dissipative metamaterial to achieve broadband wave attenuation at low-frequency ranges. The complex dispersion analysis is made on a super-cell consisting of multiple mass-in-mass unit cells. An optimization algorithm based on the sequential quadratic programming method is used to design the wave suppression of target frequencies by coupling multiple separate narrow bandgaps into a broad bandgap. A new objective function is proposed in the optimization process for a continuous bandgap. Then, the continuous frequency range with low-wave transmissibility is optimized to achieve the maximal width of bandgap. The stiffness optimization of super-cell gives the broad bandgap from 10 Hz to 22.9 Hz at low-frequency ranges. In addition, numerical simulations are conducted for a type of dissipative metamaterial composed of a finite number of periodicities. The level of vibration isolation can be tuned by adjusting a critical value in the optimization scheme. The wave suppression in the numerical simulation well coincides with the obtained bandgaps and verifies the optimization results.

Nonlinear Dynamic Analysis of Variable lead Preloaded Single Nut Ball Screw Considering the Variation of Working Parameters

In this study, a 5-degrees-of-freedom dynamic model of variable lead preloaded single nut ball screw is proposed. The proposed model considers the effect of excitation amplitude, deflection angle, the number of balls, and the preload into consideration. Moreover, to study the effect of working parameters on nonlinear dynamics, bifurcation diagram, 3-D frequency spectrum, phase diagram and Poincaré section with different system parameters are shown in discussion section. The numerical analysis indicates that the system can exhibits different motion states, and the continuous frequency component can be observed. Moreover, a series of experiments are conducted to estimate the dynamic parameters and validate the proposed dynamic model.