A Solution to Design Semi-static Null Convention Logic Cell Libraries

The Null Convention Logic (NCL) based asynchronous circuits have eliminated the disadvantages of the synchronous circuits, including noise, glitches, clock skew, power, and electromagnetic interference. However, using NCL based asynchronous designs was not easy for students and researchers because of the lack of standard NCL cell libraries. This paper proposes a solution to design a semi-static NCL cell library used to synthesize NCL based asynchronous designs. This solution will help researchers save time and effort to approach a new method. In this work, NCL cells are designed based on the Process Design Kit 45nm technology. They are simulated at the different corners with the Ocean script and Electronic Design Automation (EDA) environment to extract the timing models and the power models. These models are used to generate a *.lib file, which is converted to a *.db file by the Design Compiler tool to form a complete library of 27 cells. In addition, we synthesize the NCL based full adders to illustrate the success of the proposed library and compare our synthesis results with the results of the other authors. The comparison results indicate that power and delay are improved significantly.

Effects of periodicity in observation scheduling on parameter estimation of pulsar glitches

In certain pulsar timing experiments, where observations are scheduled approximately periodically (e.g. daily), timing models with significantly different frequencies (including but not limited to glitch models with different frequency increments) return near-equivalent timing residuals. The average scheduling aperiodicity divided by the phase error due to time-of-arrival uncertainties is a useful indicator of when the degeneracy is important. Synthetic data are used to explore the effect of this degeneracy systematically. It is found that phase-coherent tempo2 or temponest-based approaches are biased sometimes toward reporting small glitch sizes regardless of the true glitch size. Local estimates of the spin frequency alleviate this bias. A hidden Markov model is free from bias towards small glitches and announces explicitly the existence of multiple glitch solutions but sometimes fails to recover the correct glitch size. Two glitches in the UTMOST public data release are re-assessed, one in PSR J1709−4429 at MJD 58178 and the other in PSR J1452−6036 at MJD 58600. The estimated fractional frequency jump in PSR J1709−4429 is revised upward from Δf/f = (54.6 ± 1.0) × 10−9 to Δf/f = (2432.2 ± 0.1) × 10−9 with the aid of additional data from the Parkes radio telescope. We find that the available UTMOST data for PSR J1452−6036 are consistent with Δf/f = 270 × 10−9 + N/(fT) with N = 0, 1, 2, where T ≈ 1 siderealday is the observation scheduling period. Data from the Parkes radio telescope can be included, and the N = 0 case is selected unambiguously with a combined dataset.

Radio timing in a millisecond pulsar – extreme/intermediate mass ratio binary system

Radio timing observations of a millisecond pulsar in orbit around the Galactic centre black hole (BH) or a BH at the centre of globular clusters could answer foundational questions in astrophysics and fundamental physics. Pulsar radio astronomy typically employs the post-Keplerian approximation to determine the system parameters. However, in the strong gravitational field around the central BH, higher order relativistic effects may become important. We compare the pulsar timing delays given by the post-Keplerian approximation with those given by a relativistic timing model. We find significant discrepancies between the solutions derived for the Einstein delay and the propagation delay (i.e. Roemer and Sharpiro delay) compared to the fully relativistic solutions. Correcting for these higher order relativistic effects is essential in order to construct accurate radio timing models for pulsar systems at the Galactic centre and the centre of globular clusters and informing issues related to their detection.

Lumped-Parameter Response Time Models for Pneumatic Circuit Dynamics

Resistor–capacitor (RC) response time models for pressurizing and depressurizing a pneumatic capacitor (mass accumulator) through a resistor (flow restriction) comprise a framework to systematically analyze complex fluidic circuits. A model for pneumatic resistance is derived from a combination of fundamental fluid mechanics and experimental results. Models describing compressible fluid capacitance are derived from thermodynamic first principles and validated experimentally. The models are combined to derive the ordinary differential equations that describe the RC dynamics. These equations are solved analytically for rigid capacitors and numerically for deformable capacitors to generate pressure response curves as a function of time. The dynamic pressurization and depressurization response times to reach 63.2% (or 1−e−1) of exponential decay are validated in simple pneumatic circuits with combinations of flow restrictions ranging from 100 μm to 1 mm in diameter, source pressures ranging from 5 to 200 kPa, and capacitor volumes of 0.5 to 16 mL. Our RC models predict the response times, which range from a few milliseconds to multiple seconds depending on the combination, with a coefficient of determination of r2=0.983. The utility of the models is demonstrated in a multicomponent fluidic circuit to find the optimal diameter of tubing between a three-way electromechanical valve and a pneumatic capacitor to minimize the response time for the changing pressure in the capacitor. These lumped-parameter models represent foundational blocks upon which timing models of pneumatic circuits can be built for a variety of applications from soft robotics and industrial automation to high-speed microfluidics.

An Analysis of Mutual Fund Managers’ Timing Abilities - Evidence From Chinese Equity Funds

This paper examines Chinese mutual fund managers’ market, volatility, and liquidity abilities. Using a daily frequency sample of Chinese open-end equity funds from 2015 to 2019, we find evidence that mutual fund managers can time the market. Among the funds with different investment styles, the active funds have better market and liquidity timing ability, whereas the steady funds have better volatility timing ability. In different investment periods, there are more funds with timing ability in the fall period than in the rise period. We find the same results in the market (T-M), volatility, and liquidity timing models. It is especially for the active funds, nearly half of which have liquidity timing ability in the fall period. Among the funds with stock selection ability, the funds with market timing ability can outperform than the funds with other timing ability.

ISLAMIC VS CONVENTIONAL FUNDS WITHIN THE FAMILY: SELECTIVITY SKILLS AND MARKET TIMING ABILITY

ABSTRACT The aim of the study is to compare the performance of Islamic mutual fund (IMF) and conventional mutual fund (CMF) within the same family, in addition, to examine the performance of fund family in Malaysia for the period from 2007 to 2018. The study used eight measures of performance, raw returns, excess returns, Sharpe ratio, Treynor ratio, Jensen alpha, Carhart four-factor model as selectivity models, In addition to Treynor & Mazuy (TM) and Hendrickson & Merton (HM) as market timing models. The study contributes by investigating and compares the performance at the family level. The results reported that IMFs exhibited some fund selection ability over CMFs. However, both types of funds displayed poor market timing ability. At a fund family level, the results show the fund families exhibited good fund selections skills, at the same time, fund family still exhibited poor market timing ability. The novel result of this study that the difference in performance between Islamic and conventional funds shrank compared to the results of previous studies. Due to the common advantages offered by the families for both types of funds. The findings are important to investors because the results provide new evidence about the fund families' performance. Most investors follow the top-down approach, where mutual fund investors initially choose fund families before deciding which funds to hold. In addition, the results are important for managers to decide which types of funds that they may issue in their own families, so that they can perform well in the future.

How do timing mechanisms work?

This chapter addresses the nature of the general-purpose timekeeping mechanisms that are assumed in phonology-extrinsic-timing models of speech production. The first part of the chapter discusses some current questions about the nature of these mechanisms. The second part of the chapter presents Lee’s General Tau theory (Lee 1998, 2009), a theory of the temporal guidance of action in voluntary movement. This theory provides a crucial component for our phonology-extrinsic-timing-based, three-component model of speech production because its tau-coupling mechanism provides a way to plan movements with appropriate velocity profiles, as well as endpoint-based movement coordination. In doing so, it provides a general-purpose, phonology-extrinsic alternative to AP/TD’s use of oscillators for the control of the time-course of articulatory movement and coordination.