scholarly journals The local minima of fractionally-spaced CMA blind equalizer cost function in the presence of channel noise

2002 ◽  
Author(s):  
Wonzoo Chung ◽  
J.P. LeBlanc
Keyword(s):  
Cost Function ◽  
Channel Noise ◽  
Local Minima

Computational Support for Interactive Cable Harness Routing and Design

1993 ◽  
Author(s):  
Andrew B. Conru ◽  
Mark R. Cutkosky
Keyword(s):  
Cost Function ◽  
Topological Structure ◽  
Three Dimensional ◽  
Initial Guess ◽  
Local Minima ◽  
Cable Harness ◽  
Physical Constraints ◽  
Computational Support ◽  
Bending Radius

Abstract We describe a system for routing cable harnesses in complex, three-dimensional environments. The approach taken is to automate the basic routing process as much as possible, while allowing designers to guide the system and modify the numerically generated results at any stage. The system begins by quickly generating a coarse routing based on an initial guess of the cable harness configuration (topological structure). Paths are then successively refined to minimize a cost function, while satisfying physical constraints such as minimum bending radius. Human input is useful both for guiding the system away from local minima and for responding to case-specific constraints not encoded in the router.

scholarly journals Proliferation of non-linear excitations in the piecewise-linear perceptron

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Antonio Sclocchi ◽  
Pierfrancesco Urbani
Keyword(s):  
Cost Function ◽  
Optimization Problem ◽  
Hard Spheres ◽  
Piecewise Linear ◽  
Power Laws ◽  
Universality Class ◽  
Local Minima ◽  
Convex Optimization Problem ◽  
Non Linear ◽  
The Cost

We investigate the properties of local minima of the energy landscape of a continuous non-convex optimization problem, the spherical perceptron with piecewise linear cost function and show that they are critical, marginally stable and displaying a set of pseudogaps, singularities and non-linear excitations whose properties appear to be in the same universality class of jammed packings of hard spheres. The piecewise linear perceptron problem appears as an evolution of the purely linear perceptron optimization problem that has been recently investigated in [1]. Its cost function contains two non-analytic points where the derivative has a jump. Correspondingly, in the non-convex/glassy phase, these two points give rise to four pseudogaps in the force distribution and this induces four power laws in the gap distribution as well. In addition one can define an extended notion of isostaticity and show that local minima appear again to be isostatic in this phase. We believe that our results generalize naturally to more complex cases with a proliferation of non-linear excitations as the number of non-analytic points in the cost function is increased.

Detection of Malicious Spatial-Domain Steganography over Noisy Channels Using Convolutional Neural Networks

2020 ◽  
Vol 2020 (4) ◽  
pp. 76-1-76-7
Author(s):  
Swaroop Shankar Prasad ◽  
Ofer Hadar ◽  
Ilia Polian
Keyword(s):  
State Of The Art ◽  
Visual Quality ◽  
Channel Noise ◽  
Detection Accuracy ◽  
Noisy Channel ◽  
Noisy Channels ◽  
Reliable Transmission ◽  
Reliable Detection ◽  
Natural Noise ◽  
Will Force

Image steganography can have legitimate uses, for example, augmenting an image with a watermark for copyright reasons, but can also be utilized for malicious purposes. We investigate the detection of malicious steganography using neural networkbased classification when images are transmitted through a noisy channel. Noise makes detection harder because the classifier must not only detect perturbations in the image but also decide whether they are due to the malicious steganographic modifications or due to natural noise. Our results show that reliable detection is possible even for state-of-the-art steganographic algorithms that insert stego bits not affecting an image’s visual quality. The detection accuracy is high (above 85%) if the payload, or the amount of the steganographic content in an image, exceeds a certain threshold. At the same time, noise critically affects the steganographic information being transmitted, both through desynchronization (destruction of information which bits of the image contain steganographic information) and by flipping these bits themselves. This will force the adversary to use a redundant encoding with a substantial number of error-correction bits for reliable transmission, making detection feasible even for small payloads.

Estimacion de Economias de Escala en el Mercado de Tarjetas de Pago

2019 ◽  
Vol 12 (2) ◽  
pp. 86-92
Keyword(s):  
Cost Function ◽  
Economies Of Scale ◽  
Payment Methods ◽  
Per Se ◽  
Main Banks ◽  
Debit Cards

During the last years, the growth of transactions made through credit and debit cards has presented quite signif- icant increases both in number and in amounts. This paper studies the existence of economies of scale in the pro- cessing of such transactions, a situation that would exist if it were compatible with the existence of a single firm destined to the processing of said operations. The existence of a single firm for processing is not in itself a problem per se, which does generate problems for the competition is the structure of said firm, because for the period of time analyzed, its shareholder composition was composed of The main banks that issue these cards, but also have given them the function of being the acquirer of the merchants for these payment methods, which generates a vertically inte- grated structure, which creates competition problems in the market. After estimating the model indirectly from a cost function, this work determines the existence of economies of scale in the industry.

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