An improved instruction-level power model for ARM11 microprocessor

The power and energy consumed by a chip has become the primary design constraint for embedded systems, which has led to a lot of work in hardware design techniques such as clock gating and power gating. The software can also affect the power usage of a chip, hence good software design can be used to reduce the power further. In this paper we present an instruction-level power model based on an ARM1176JZF-S processor to predict the power of software applications. Our model takes substantially less input data than existing high accuracy models and does not need to consider each instruction individually. We show that the power is related to both the distribution of instruction types and the operations per clock cycle (OPC) of the program. Our model does not need to consider the effect of two adjacent instructions, which saves a lot of calculation and measurements. Pipeline stall effects are also considered by OPC instead of cache miss, because there are a lot of other reasons that can cause the pipeline to stall. The model shows good performance with a maximum estimation error of -8.28\% and an average absolute estimation error is 4.88\% over six benchmarks. Finally, we prove that energy per operation (EPO) decreases with increasing operations per clock cycle, and we confirm the relationship empirically

α\alpha-Logarithmic negativity

The logarithmic negativity of a bipartite quantum state is a widely employed entanglement measure in quantum information theory, due to the fact that it is easy to compute and serves as an upper bound on distillable entanglement. More recently, the $\kappa$-entanglement of a bipartite state was shown to be the first entanglement measure that is both easily computable and has a precise information-theoretic meaning, being equal to the exact entanglement cost of a bipartite quantum state when the free operations are those that completely preserve the positivity of the partial transpose [Wang and Wilde, Phys. Rev. Lett. 125(4):040502, July 2020]. In this paper, we provide a non-trivial link between these two entanglement measures, by showing that they are the extremes of an ordered family of $\alpha$-logarithmic negativity entanglement measures, each of which is identified by a parameter $\alpha\in[ 1,\infty]$. In this family, the original logarithmic negativity is recovered as the smallest with $\alpha=1$, and the $\kappa$-entanglement is recovered as the largest with $\alpha=\infty$. We prove that the $\alpha$-logarithmic negativity satisfies the following properties: entanglement monotone, normalization, faithfulness, and subadditivity. We also prove that it is neither convex nor monogamous. Finally, we define the $\alpha$-logarithmic negativity of a quantum channel as a generalization of the notion for quantum states, and we show how to generalize many of the concepts to arbitrary resource theories.Comment: v3: 15 pages, accepted for publication in Physical Review

Real convergence and regime-switching among EU accession countries

Real convergence among the ten EU 2004 accession economies is investigated with respect to long-run real interest parity. We employ a novel approach where unit-root tests for real interest differentials are embedded within a Markov regime-switching framework. Whereas standard univariate unit-root tests provide mixed support for parity, we find parity is present in all cases where differentials either switch between regimes of stationary and non-stationarity behaviour, or between alternative regimes of stationarity characterized by differing degrees of persistence. Further insights are obtained from the inferred probabilities of being in each regime, and the regime-switching nature of the differential variances

Exact entanglement cost of quantum states and channels under PPT-preserving operations

This paper establishes single-letter formulas for the exact entanglement cost of generating bipartite quantum states and simulating quantum channels under free quantum operations that completely preserve positivity of the partial transpose (PPT). First, we establish that the exact entanglement cost of any bipartite quantum state under PPT-preserving operations is given by a single-letter formula, here called the $\kappa$-entanglement of a quantum state. This formula is calculable by a semidefinite program, thus allowing for an efficiently computable solution for general quantum states. Notably, this is the first time that an entanglement measure for general bipartite states has been proven not only to possess a direct operational meaning but also to be efficiently computable, thus solving a question that has remained open since the inception of entanglement theory over two decades ago. Next, we introduce and solve the exact entanglement cost for simulating quantum channels in both the parallel and sequential settings, along with the assistance of free PPT-preserving operations. The entanglement cost in both cases is given by the same single-letter formula and is equal to the largest $\kappa$-entanglement that can be shared by the sender and receiver of the channel. It is also efficiently computable by a semidefinite program.Comment: 54 pages, 8 figures; comments are welcome

Water Vapor and Cloud Formation in the TTL: Simulation Results vs. Satellite Observations

Driven by analyzed winds and temperature, domain-filling forward trajectory calculations are used to reproduce water vapor and cloud formations in the tropical tropopause layer (TTL). As with most Lagrangian models of this type, excess water vapor is instantaneously removed from the parcel to keep the relative humidity with respect to ice from exceeding a specified (super) saturation level. The dehydration occurrences serve as an indication of where and when cloud forms. Convective moistening through ice lofting and gravity waves are also included in our simulations as mechanisms that could affect water vapor abundances and cloud formations in the TTL. Our simulations produce water vapor mixing ratios close to that observed by the Aura Microwave Limb Sounder (MLS) and are consistent with the reanalysis tropical tropopause temperature biases, which proves the importance of the cold-point temperature to the water vapor abundances in the stratosphere. The simulation of cloud formation agrees with the patterns of cirrus distribution from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). It proves that the trajectory calculations fed by the analyzed wind and temperature could produce reasonable simulations of water vapor and cloud formation in the TTL