Dynamic Virtual Page-based Flash Translation Layer with Novel Hot Data Identification and Adaptive Parallelism Management

Solid-state disks (SSDs) tend to replace traditional motor-driven hard disks in high-end storage devices in past few decades. However, various inherent features, such as out-of-place update [resorting to garbage collection (GC)] and limited endurance (resorting to wear leveling), need to be reduced to a large extent before that day comes. Both the GC and wear leveling fundamentally depend on hot data identification (HDI). In this paper, we propose a hot data-aware flash translation layer architecture based on a dynamic virtual page (DVPFTL) so as to improve the performance and lifetime of NAND flash devices. First, we develop a generalized dual layer HDI (DL-HDI) framework, which is composed of a cold data pre-classifier and a hot data post-identifier. Those can efficiently follow the frequency and recency of information access. Then, we design an adaptive parallelism manager (APM) to assign the clustered data chunks to distinct resident blocks in the SSD so as to prolong its endurance. Finally, the experimental results from our realized SSD prototype indicate that the DVPFTL scheme has reliably improved the parallelizability and endurance of NAND flash devices with improved GC-costs, compared with related works.Peer reviewe

Deep Graph Laplacian Regularization for Robust Denoising of Real Images

Recent developments in deep learning have revolutionized the paradigm of image restoration. However, its applications on real image denoising are still limited, due to its sensitivity to training data and the complex nature of real image noise. In this work, we combine the robustness merit of model-based approaches and the learning power of data-driven approaches for real image denoising. Specifically, by integrating graph Laplacian regularization as a trainable module into a deep learning framework, we are less susceptible to overfitting than pure CNN-based approaches, achieving higher robustness to small datasets and cross-domain denoising. First, a sparse neighborhood graph is built from the output of a convolutional neural network (CNN). Then the image is restored by solving an unconstrained quadratic programming problem, using a corresponding graph Laplacian regularizer as a prior term. The proposed restoration pipeline is fully differentiable and hence can be end-to-end trained. Experimental results demonstrate that our work is less prone to overfitting given small training data. It is also endowed with strong cross-domain generalization power, outperforming the state-of-the-art approaches by a remarkable margin

On-Shell Gauge Invariant Three-Point Amplitudes

Assuming locality, Lorentz invariance and parity conservation we obtain a set of differential equations governing the 3-point interactions of massless bosons, which in turn determines the polynomial ring of these amplitudes. We derive all possible 3-point interactions for tensor fields with polarisations that have total symmetry and mixed symmetry under permutations of Lorentz indices. Constraints on the existence of gauge-invariant cubic vertices for totally symmetric fields are obtained in general spacetime dimensions and are compared with existing results obtained in the covariant and light-cone approaches. Expressing our results in spinor helicity formalism we reproduce the perhaps mysterious mismatch between the covariant approach and the light cone approach in 4 dimensions. Our analysis also shows that there exists a mismatch, in the 3-point gauge invariant amplitudes corresponding to cubic self-interactions, between a scalar field $\phi$ and an antisymmetric rank-2 tensor field $A_{\mu\nu}$. Despite the well-known fact that in 4 dimensions rank-2 anti-symmetric fields are dual to scalar fields in free theories, such duality does not extend to interacting theories.Comment: significantly revised, final version published in JHE

Miniature transparent UWB antenna with tunable notch for green wireless applications

Copyright @ 2011 IEEEA miniature transparent UWB antenna with tunable notch that can be incorporated with a solar panel for harnessing solar energy has been proposed and presented. The antenna demonstrates a good omni-directional radiation pattern throughout the FCC bandwidth of 3.1 – 10.6 GHz and a comparable gain making it a good candidate for future green wireless applications

Slip energy barriers in aluminum and implications for ductile versus brittle behavior

We conisder the brittle versus ductile behavior of aluminum in the framework of the Peierls-model analysis of dislocation emission from a crack tip. To this end, we perform first-principles quantum mechanical calculations for the unstable stacking energy $\gamma_{us}$ of aluminum along the Shockley partial slip route. Our calculations are based on density functional theory and the local density approximation and include full atomic and volume relaxation. We find that in aluminum $\gamma_{us} = 0.224$ J/m$^2$. Within the Peierls-model analysis, this value would predict a brittle solid which poses an interesting problem since aluminum is typically considered ductile. The resolution may be given by one of three possibilites: (a) Aluminum is indeed brittle at zero temperature, and becomes ductile at a finite temperature due to motion of pre-existing dislocations which relax the stress concentration at the crack tip. (b) Dislocation emission at the crack tip is itself a thermally activated process. (c) Aluminum is actually ductile at all temperatures and the theoretical model employed needs to be significantly improved in order to resolve the apparent contradiction.Comment: 4 figures (not included; send requests to [email protected]

Design of 5 th-order analog predistorter

This paper presents the design of a 5th-order analog predistorter to suppress the 3rd-and 5th-order intermodulation distortion products (EVTDP3 and EVTDP5) at the output of a base-station power amplifiers (PAs). The predistorter consists of two mixers: one mixer generating the 3rd-order intermodulation (IM3) products and another mixer of same configuration generating the 5th-order intermodulation (IM5) products using the IM3 products generated by the other mixer, thus simplifying the design and hardware implementation. The predistorter is implemented and tested using two-tone and the CDMA (IS-95) signals at 2.2GHz in a practical 10W-PA. The two-tone test results show that the proposed predistorter can suppress the IMDP3 and IMDP5 by 17dB and lldB, respectively. For the CDMA (IS-95) test, results show that the predistorter can improve the adjacent channel power ratio (ACPR) by 10 dB at ± 887 kHz from the center frequency. © 2010 IEEE.published_or_final_versionThe 2010 IEEE Region 10 International Conference (TENCON 2010), Fukuoka, Japan, 21-24 November 2010. In TENCON (IEEE Region 10 Conference) Proceedings, 2010, p. 876-87

A reappraisal of the border effect on relative price volatility

Engel and Rogers (1996) find that crossing the US-Canada border can considerably raise relative price volatility and that exchange rate fluctuations explain about one-third of the volatility increase. In re-evaluating the border effect, this study shows that cross-country heterogeneity in price volatility can lead to significant bias in measuring the border effect unless proper adjustment is made to correct it. The analysis explores the implication of symmetric sampling for border effect estimation. Moreover, using a direct decomposition method, two conditions governing the strength of the border effect are identified. In particular, the more dissimilar the price shocks are across countries, the greater the border effect will be. Decomposition estimates also suggest that exchange rate fluctuations actually account for a large majority of the border effect

A 5 th-order analog predistorter for NADC system

This paper presents the design of a 5th-order analog predistorter using the inband intermodulation (IM) signals for predistortion of base-station high power amplifiers (HPAs) for the North American Digital Cellular (NADC) system. The predistorter employs two mixers with same configuration to generate 3rd-order intermodulation (IM3) products and 5th-order intermodulation (IM5) products, to suppress the 3 rd-and 5th-order intermodulation distortion products (IMDP3 and IMDP5) at the HPA output. The predistorter is implemented and tested using the pi/4-DQPSK signal of the NADC system at 2.2GHz in a practical 100W-HPA. The results show that, at the HPA output powers of 65.6, 56.2, 50 and 41.3 W, the predistorter can suppress the adjacent channel power ratio (ACPR) of the pi/4-DQPSK signal at ± 20 kHz from the center frequency by 15.16, 15.83, 16.17 and 15.17 dB, respectively. © 2010 IEEE.published_or_final_versionThe 12th IEEE International Conference on Communication Systems (ICCS 2010), Singapore, 17-19 November 2010. In Proceedings of 12th ICCS, 2010, p. 19-2

Planar Monopoles with Different Radiator Shapes for UWB Body-centric Wireless Communications

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