Multilevel Dataflow-Driven Macro Placement Guided by RTL Structure and Analytical Methods

Crack evolution mechanism of stratified rock mass under different strength ratios and soft layer thickness: Insights from DEM modeling

Placement is one of the most important problems in electronic design automation. Although it has been investigated for several decades, a more efficient core engine is critically needed for the following reasons: (1) design scale becomes huge; (2) placement is typically run again and again to explore the design space at early design stages (e.g., physical synthesis); (3) placement core engine is called many times to iteratively optimize other objectives (e.g., timing and routability). In this paper, we propose a new ultrafast global placement engine called POLAR 3.0, which explores parallelism in state-of-the-art quadratic placer. POLAR 3.0 can make full use of multi-core system and it delivers 7–30× speedup over state-of-the-art academic placers by using a 8-core CPU, while the solution quality is competitive.

Evaluation of the angular distribution function of particles scattered in an amorphous medium is improved by deforming the integration path in the Fourier integral representation into the complex plane. That allows us to present the distribution function as a sum of two positive components, soft and hard, the soft component being close to a Gaussian, and the hard component vanishing in the forward direction, while including the Rutherford asymptotics and all the power corrections to it at large scattering angles. Detailed properties of those components, and their interplay at intermediate deflection angles are discussed. Comparison with the Moli\`{e}re theory is given.

AN ULTRASOFT EINSTEIN X-RAY SURVEY

We present results from ASCA observations of the binary CI Cam both in quiescence and in outburst in order to identify its central accreting object. The quiescence spectrum of CI Cam consists of soft and hard components, which are separated clearly at around 2-3 keV. A large equivalent width of an iron K? emission line prefers an optically thin thermal plasma emission model to a nonthermal power-law model for the hard component, which favors a white dwarf as the accreting object, since optically thin thermal hard X-ray emission is a common characteristic among cataclysmic variables (binaries including an accreting white dwarf). However, since the power-law model, which represents the X-ray spectrum of the soft X-ray transients in quiescence, provides an equally good fit to the hard component statistically, we cannot exclude the possibility of a neutron star or a black hole from the quiescence data. The outburst spectrum, on the other hand, is composed of a hard component represented by multitemperature optically thin thermal plasma emission and an independent soft X-ray component that appears below 1 keV intermittently on a decaying light curve of the hard component. The spectrum of the soft component is represented well by a blackbody with the temperature of 0.07-0.12 keV overlaid with several K edges associated with highly ionized oxygen. This, together with the luminosity as high as ~1 ? 1038 ergs s-1, is similar to a supersoft source. The outburst in the hard X-ray band followed by the appearance of the soft blackbody component reminds us of recent observations of novae in outburst. We thus assume that the outburst of CI Cam is that of a nova and obtain the distance to CI Cam of 5-17 kpc by means of the relation between the optical decay time and the absolute magnitude. This agrees well with a recent estimate of the distance of 5-9 kpc in the optical band. All of these results from the outburst data prefer a white dwarf for the central object of CI Cam.

It is generally recognized that the cosmic radiation in the atmosphere consists of two components, the hard component and the soft. The interpretation of the soft component as the product of primary electrons which multiply in passing through the atmosphere according to the well‐known quantum mechanical principles is completely satisfactory but the hard component presents some serious difficulties. Its particles, the mesotrons, are undoubtedly produced as secondaries within the atmosphere, but what kind of primary particles produce the mesotrons has been until now an unsolved problem. If those particles were the electrons of the soft component, the soft component like the hard component would have to possess the distinguishing characteristic of its positive primaries of being asymmetrically distributed in angle in the regions near the equator. On the other hand, if the two components are independent, the soft component might show no asymmetry despite the fact that the hard component is known to be so strongly asymmetric that it must have been produced entirely by positive primaries.

Quantum circuit design flow consists of two main tasks: synthesis and physical design. Addressing the limitations imposed on optimization of the quantum circuit objectives because of no information sharing between synthesis and physical design processes, we introduced the concept of "physical synthesis" for quantum circuit flow and proposed a technique for it. Following that concept, in this paper we propose a new technique for physical synthesis using auxiliary qubit selection to improve the latency of quantum circuits. Moreover, it will be shown that the auxiliary qubit selection technique can be seamlessly integrated into the previously introduced physical synthesis flow. Our experimental results show that the proposed technique decreases the average latency objective of quantum circuits by about 11% for the attempted benchmarks.

We present here results obtained from three BeppoSAX observations of the accretion-powered X-ray pulsar SMC X-1 carried out during the declining phases of its 40--60 days long super-orbital period. Timing analysis of the data clearly shows a continuing spin-up of the neutron star. Energy-resolved timing analysis shows that the pulse-profile of SMC X-1 is single peaked at energies less than 1.0 keV whereas an additional peak, the amplitude of which increases with energy within the MECS range, is present at higher energies. Broad-band pulse-phase-averaged spectroscopy of the BeppoSAX data, which is done for the first time since its discovery, shows that the energy spectrum in the 0.1--80 keV energy band has three components, a soft excess that can be modeled as a thermal black-body, a hard power-law component with a high-energy exponential cutoff and a narrow and weak iron emission line at 6.4 keV. Pulse-phase resolved spectroscopy indicates a pulsating nature of the soft spectral component, as seen in a few other binary X-ray pulsars, with a certain phase offset with respect to the hard power-law component. Dissimilar shape and phase of the soft and hard X-ray pulse profiles suggest a different origin of the soft and hard components.

This paper describes the modular magnetic assembly of reconfigurable, pneumatically actuated robots composed of soft and hard components and materials. The soft components of these hybrid robots are actuators fabricated from silicone elastomers using soft lithography, and the hard components are acrylonitrile–butadiene–styrene (ABS) structures made using 3D printing. Neodymium–iron–boron (NdFeB) ring magnets are embedded in these components to make and maintain the connections between components. The reversibility of these magnetic connections allows the rapid reconfiguration of these robots using components made of different materials (soft and hard) that also have different sizes, structures, and functions; in addition, it accelerates the testing of new designs, the exploration of new capabilities, and the repair or replacement of damaged parts. This method of assembling soft actuators to build soft machines addresses some limitations associated with using soft lithography for the direct molding of complex 3D pneumatic networks. Combining the self‐aligning property of magnets with pneumatic control makes it possible for a teleoperator to modify the structures and capabilities of these robots readily in response to the requirements of different tasks.

It is now generally agreed that the cosmic radiation consists of two groups called the soft and the hard component. This classification refers to the penetrating power of the particles in question. The soft component consists of ordinary electrons and light quanta, whereas it now seems very probable that the hard group consists of "heavy electrons". The phenomena connected with the soft component are described by the cascade theory of showers put forward by Bhabha and Heitler (1937) and Carlson and Oppenheimer (1937). It is the purpose of the present paper to work out the consequences of the theory in greater detail in order to make possible a more quantitative comparison between theory and experiment than has hitherto been possible. This is desirable for several reasons: In the first place it is important to ascertain whether the phenomena connected with the soft component can be accountant for completely by the cascade theory or whether some of the facts require an explanation outside the present relativistic quantum mechanics.

We present measurements of the 0.05-10 MeV gamma-ray spectra as a function of longitude from the inner Galactic ridge using the Oriented Scintillation Spectrometer Experiment (OSSE) on the Compton Gamma Ray Observatory. The differential continuum emission relative to intensities at ±10° Galactic latitude appears to be a composite of at least three independent components: a soft low-energy component with a broad longitude distribution and with spectra well approximated by an exponentially absorbed power law; a hard component with a similarly broad longitude distribution modeled by a power law from ~200 keV to 10 MeV with photon index ~-1.75; and strong positron annihilation line and continuum contributions observed toward the center with intensities that decrease rapidly with longitude distance from the center. Although OSSE cannot distinguish between a simple one-component latitude distribution and a more complicated one with, for example, broad and narrow latitude components, an effective 5°-6° FWHM Gaussian latitude width gives a spectrum and intensity for the power-law component that agrees with extrapolations of measurements at higher energies using a cosmic-ray interaction model. However, the latitude distribution of the emission is not well measured. Near the Galactic center, bright variable sources contribute significantly to the low-energy spectrum. When account is taken of these variable-source contributions, both the soft low-energy and hard power-law components show a consistent longitude distribution that follows the Galactic matter distribution as evidenced by the Galactic CO distribution. These results, in conjunction with previous measurements, provide new information for determining the Galactic cosmic-ray electron spectrum at lower energies.

On the correlation between roping, texture, and morphology of aluminium alloy sheets

To investigate the physics of mass accretion onto weakly-magnetized neutron stars, 95 archival RXTE datasets of an atoll source 4U 1608-522, acquired over 1996-2004 in so-called upper-banana state, were analyzed. The object meantime exhibited 3-30 keV luminosity in the range of <~ 10^35 - 4 x 10^37 erg s^-1, assuming a distance of 3.6 kpc. The 3-30 keV PCA spectra, produced one from each dataset, were represented successfully with a combination of a soft and a hard component, of which the presence was revealed in a model-independent manner by studying spectral variations among the observations. The soft component is expressed by so-called multi-color disk model with a temperature of ~1.8 keV, and is attributed to the emission from an optically-thick standard accretion disk. The hard component is a blackbody emission with a temperature of ~2.7 keV, thought to be emitted from the neutron-star surface. As the total luminosity increases, a continuous decrease was observed in the ratio of the blackbody luminosity to that of the disk component. This property suggests that the matter flowing through the accretion disk gradually becomes difficult to reach the neutron-star surface, presumably forming outflows driven by the increased radiation pressure. On time scales of hours to days, the overall source variability was found to be controlled by two independent variables; the mass accretion rate, and the innermost disk radius which changes both physically and artificially.

Optimizations developed in earlier chapters affect many aspects of physical synthesis, but often target sequential elements, which particularly impact circuit performance. In order to obtain synergies between these optimizations, we explore the infrastructure for physical synthesis used by IBM for large commercial microprocessor designs. We focus our attention on a very challenging high-performance design style called large-block synthesis (LBS). In such designs latch placement is critical to the performance of the clock network, which in turn affects chip timing and power. Our research uncovers deficiencies in the state-of-the-art physical synthesis flow vis-à-vis latch placement that result in timing disruptions and hamper design closure. We introduce a next-generation EDA methodology that improves timing closure through careful latch placement and clock-network routing to (i) avoid timing degradation where possible, and (ii) immediately recover from unavoidable timing disruptions. When evaluated on large CPU designs recently developed at IBM, our methodology leads to double-digit improvements in key circuit parameters, compared to IBMs prior state-of-the-art methodologies.KeywordsSlew RateTiming DegradationCombinational LogicPlacement AlgorithmLogic SynthesisThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Performance analysis is a subdiscipline of sports sciences and one-approach, notational analysis, has been used to objectively audit and describe behaviours of performers during different subphases of play, providing additional information for practitioners to improve future sports performance. Recent criticisms of these methods have suggested the need for a sound theoretical rationale to explain performance behaviours, not just describe them. The aim of this article was to show how ecological dynamics provides a valid theoretical explanation of performance in team sports by explaining the formation of successful and unsuccessful patterns of play, based on symmetry-breaking processes emerging from functional interactions between players and the performance environment. We offer the view that ecological dynamics is an upgrade to more operational methods of performance analysis that merely document statistics of competitive performance. In support of our arguments, we refer to exemplar data on competitive performance in team sports that have revealed functional interpersonal interactions between attackers and defenders, based on variations in the spatial positioning of performers relative to each other in critical performance areas, such as the scoring zones. Implications of this perspective are also considered for practice task design and sport development programmes.