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No 78
Vol. 78 No. 18
2020
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To communicate with people interactive systems often need to understand human activities in advance. However, recognizing activities in advance is a very challenging task, because people perform their activities in different ways, also, some activities are simple while others are complex and comprised of several smaller atomic sub-activities. In this paper, we use skeletons captured from low-cost depth RGB-D sensors as high-level descriptions of the human body. We propose a method capable of recognizing simple and complex human activities by formulating it as a structured prediction task using probabilistic graphical models (PGM). We test our method on three popular datasets: CAD-60, UT-Kinect, and Florence 3D. These datasets cover both simple and complex activities. Also, our method is sensitive to clustering methods that are used to determine the middle states, we evaluate test different clustering, methods.
Mohammad Mahdi Arzani - M. Fathy - ahmad Akbari
Keywords : Probabilistic graphical models ، human activity recognition ، distributed structured prediction ، skeleton
AMP is a low-cost iterative algorithm for recovering signal in compressed sensing. When the sampling matrix has IID zero-mean Gaussian elements, the convergence of AMP is analytically guaranteed. But for other sampling matrices, especially ill-conditioned matrices, the recovery performance of AMP degrades and even may be diverged. This problem limits the use of AMP in some applications such as imaging. In this paper, a method is proposed for modifying the AMP algorithm based on Bayesian theory for non-IID matrices. Simulation results show better robustness properties of the proposed algorithm for non-IID matrices in comparison with previous works. In other words, the proposed method has more precision in recovery, and converges with less iterations.
F. Ansari Ram - M. Khademi - Abbas Ebrahimi moghadam - H. Sadoghi Yazdi
Keywords : Approximate message passing ، compressed sensing ، IID Gaussian matrices ، low-rank product matrices ، row orthogonal matrices ، ،
Heterogeneous networks have been regarded as an integral part of fifth generation communication networks in order to respond to the unprecedented growth of required data rates. In such networks, the existence of a variety of cells with base stations of varying capacities and transmit powers has enabled the repeated use of available bandwidth. Moreover, the excess load on the central base station can be directed to the sub-cell base stations. In the current work, a novel approach is proposed for such a load balancing problem in which some nodes previously connected to the main base station can be served by sub-cells through the use of some D2D relays. This will increase the overall network capacity, improve the quality of service (QoS) of cell edge users, and increase covered users. In this design, the maximization of the capacity of D2D links is formulated as an optimization problem which is not convex in general. To tackle this, the main problem is divided into two sub-problems of optimal resource allocation and user-relay pairing problems with much lower complexity. Simulation results demonstrate the superiority of the proposed method over existing works addressed in the literature.
shahriar gholami mehrabadi - yasser attar izi - soroush akhlaghi
Keywords : Device to device communication ، resource allocation ، frequency division ، heterogeneous networks ، load balancing
This paper focuses on the effect of heterogeneous cache hierarchy in data center processors in the dark silicon era. For extreme-scale high performance computing systems, system-wide power consumption has been identified as one of the key constraints. As energy consumption becomes a key issue for operation and maintenance of cloud data centers, cloud computing providers are becoming significantly concerned. Emerging non-volatile memory technologies are favorable replacement for conventional memory. Here, we employ a nonvolatile memory called spin-transfer torque random access memory (STT-RAM) as an on-chip L2 cache to obtain lower energy compared to conventional L2 caches, like SRAM. High density, fast read access, near-zero leakage power and non-volatility make STT-RAM a significant technology for on-chip memories. In order to decrease memory energy consumption, it is required to address both the leakage and dynamic energy. Previous studies have mainly studied specific schemes based on common applications and do not provide a thorough analysis of emerging scale-out applications with multiple design options. Here, we discuss different outlooks consisting of performance and energy efficiency in cloud processors by running CloudSuite benchmarks as one of scale-out workloads. Experiment results on the CloudSuite benchmarks show that using STT-RAM memory compare to SRAM memory as last level cache, consumes less energy in L2 cache, around 59% at maximum.
Adnan Nasri - M. Fathy - Ali Broumandnia
Keywords : Cloud data center ، processor ، cache hierarchy ، nonvolatile memory ، CloudSuite benchmark
By increasing the precision of steganalysis attacks in discovering methods of steganography, the need to improve the security of steganographic methods is felt more than ever. The LSBM is one of the simplest methods of steganography, which have been proposed relatively successful attacks for its discovery. The main purpose of this paper is to provide a method for improving security of LSBM. The choice of the sequence of pixels to embed and how to modify them varies in LSBM-based methods. In most existing methods some of these decisions are made at random. In the proposed method in this paper, a multi-key idea in the first step and a genetic algorithm in the second step are used to make better decisions. In the proposed method, as MKGM, the image is blocked and GLSBM is executed for each block with different keys and finally the block with the least histogram change compared to the original block is included in the stego image. The GLSBM method is the same as the LSBM method except that the genetic algorithm is used to decide whether to increase or decrease non-matching pixels. Comparison of the image quality criteria and the accuracy of the attacks in the detection of the proposed method show that these criteria are improved compared to the original LSBM method.
vajiheh sabeti - Sepide faiazi - hadise shirinkhah
Keywords : Steganography ، steganalysis ، LSBM ، genetic algorithm

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