scholarly journals Efficient Optimization ofF-Measure with Cost-Sensitive SVM

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Fan Cheng ◽  
Yuan Zhou ◽  
Jian Gao ◽  
Shuangqiu Zheng
Keyword(s):  
Large Scale ◽  
Line Search ◽  
Performance Metrics ◽  
Empirical Studies ◽  
Closed Form Solution ◽  
Form Solution ◽  
Bundle Method ◽  
Additional Line ◽  
Direct Optimization ◽  
Current State

F-measure is one of the most commonly used performance metrics in classification, particularly when the classes are highly imbalanced. Direct optimization of this measure is often challenging, since no closed form solution exists. Current algorithms design the classifiers by using the approximations to theF-measure. These algorithms are not efficient and do not scale well to the large datasets. To fill the gap, in this paper, we propose a novel algorithm, which can efficiently optimizeF-measure with cost-sensitive SVM. First of all, we present an explicit transformation from the optimization ofF-measure to cost-sensitive SVM. Then we adopt bundle method to solve the inner optimization. For the problem where the existing bundle method may have the fluctuations in the primal objective during iterations, an additional line search procedure is involved, which can alleviate the fluctuations problem and make our algorithm more efficient. Empirical studies on the large-scale datasets demonstrate that our algorithm can provide significant speedups over current state-of-the-artF-measure based learners, while obtaining better (or comparable) precise solutions.

scholarly journals Reconstruction of three-dimensional maps based on closed-form solutions of the variational problem of multisensor data registration

2019 ◽  
Vol 484 (6) ◽  
pp. 672-677
Author(s):  
A. V. Vokhmintcev ◽  
A. V. Melnikov ◽  
K. V. Mironov ◽  
V. V. Burlutskiy
Keyword(s):  
Closed Form ◽  
Large Scale ◽  
Three Dimensional ◽  
Dynamic Environment ◽  
Closed Form Solution ◽  
Point Clouds ◽  
Accurate Method ◽  
Form Solution ◽  
Closed Form Solutions ◽  
Reconstruction Methods

A closed-form solution is proposed for the problem of minimizing a functional consisting of two terms measuring mean-square distances for visually associated characteristic points on an image and meansquare distances for point clouds in terms of a point-to-plane metric. An accurate method for reconstructing three-dimensional dynamic environment is presented, and the properties of closed-form solutions are described. The proposed approach improves the accuracy and convergence of reconstruction methods for complex and large-scale scenes.

scholarly journals Maximizing Nonlocal Self-Similarity Prior for Single Image Super-Resolution

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Jianhong Li ◽  
Kanoksak Wattanachote ◽  
Yarong Wu
Keyword(s):  
Large Scale ◽  
Closed Form Solution ◽  
Solution Space ◽  
Super Resolution ◽  
Gaussian Mixture ◽  
Form Solution ◽  
Single Image ◽  
Self Similarity ◽  
Image Super Resolution ◽  
Single Image Super Resolution

Prior knowledge plays an important role in the process of image super-resolution reconstruction, which can constrain the solution space efficiently. In this paper, we utilized the fact that clear image exhibits stronger self-similarity property than other degradated version to present a new prior called maximizing nonlocal self-similarity for single image super-resolution. For describing the prior with mathematical language, a joint Gaussian mixture model was trained with LR and HR patch pairs extracted from the input LR image and its lower scale, and the prior can be described as a specific Gaussian distribution by derivation. In our algorithm, a large scale of sophisticated training and time-consuming nearest neighbor searching is not necessary, and the cost function of this algorithm shows closed form solution. The experiments conducted on BSD500 and other popular images demonstrate that the proposed method outperforms traditional methods and is competitive with the current state-of-the-art algorithms in terms of both quantitative metrics and visual quality.

scholarly journals Generalized analog thresholding for spike acquisition at ultralow sampling rates

2015 ◽  
Vol 114 (1) ◽  
pp. 746-760 ◽  
Author(s):  
Bryan D. He ◽  
Alex Wein ◽  
Lav R. Varshney ◽  
Julius Kusuma ◽  
Andrew G. Richardson ◽  
...  
Keyword(s):  
Compressive Sensing ◽  
Large Scale ◽  
Closed Form Solution ◽  
Form Solution ◽  
New Method ◽  
Multielectrode Arrays ◽  
Base Method ◽  
Order Of Magnitude ◽  
Signal Processing Methods ◽  
Spike Waveforms

Efficient spike acquisition techniques are needed to bridge the divide from creating large multielectrode arrays (MEA) to achieving whole-cortex electrophysiology. In this paper, we introduce generalized analog thresholding (gAT), which achieves millisecond temporal resolution with sampling rates as low as 10 Hz. Consider the torrent of data from a single 1,000-channel MEA, which would generate more than 3 GB/min using standard 30-kHz Nyquist sampling. Recent neural signal processing methods based on compressive sensing still require Nyquist sampling as a first step and use iterative methods to reconstruct spikes. Analog thresholding (AT) remains the best existing alternative, where spike waveforms are passed through an analog comparator and sampled at 1 kHz, with instant spike reconstruction. By generalizing AT, the new method reduces sampling rates another order of magnitude, detects more than one spike per interval, and reconstructs spike width. Unlike compressive sensing, the new method reveals a simple closed-form solution to achieve instant (noniterative) spike reconstruction. The base method is already robust to hardware nonidealities, including realistic quantization error and integration noise. Because it achieves these considerable specifications using hardware-friendly components like integrators and comparators, generalized AT could translate large-scale MEAs into implantable devices for scientific investigation and medical technology.

Effect of rotation on wave propagation through a poroelastic wet bone with cavity

2019 ◽  
Vol 16 (1) ◽  
pp. 53-72
Author(s):  
A.M. Abd-Alla ◽  
S.M. Abo-Dahab ◽  
Roqia Ateeq ◽  
Moaiad A. Khder
Keyword(s):  
Wave Propagation ◽  
Large Scale ◽  
Mechanical Response ◽  
Practical Importance ◽  
Engineering Application ◽  
Closed Form Solution ◽  
Form Solution ◽  
Long Bone ◽  
Content Type ◽  
Bio Engineering

Purpose The purpose of this paper is to investigate the wave propagation of wave in an infinite poroelastic cylindrical bone. The dynamic behavior of a wet long bone that has been modeled as a piezoelectric hollow cylinder of crystal class 6 is investigated. Design/methodology/approach An exact closed form solution is presented by employing an analytical procedure. The frequency equation for poroelastic bone is obtained when the boundaries are stress free and is examined numerically. Findings The study of wave propagation over a continuous medium is of practical importance in the field of engineering, medicine and bio-engineering. Application of the poroelastic materials in medicinal fields such as orthopedics, dental and cardiovascular is well known. In orthopedics, wave propagation over bone is used in monitoring the rate of fracture healing. There are two types of osseous tissue, such as cancellous or trabecular and compact or cortical bone, which are of different materials, with respect to their mechanical behavior. Originality/value The frequencies are calculated for poroelastic bone for various values for different values of rotation, angular velocity and density. In wet bone little velocity dispersion was observed, in contrast to the results of earlier studies on wet bone. Large values of attenuation were observed. Such a model would in particular be useful in large-scale parametric studies of bone mechanical response.

MODELING A FLEXIBLE RETIREMENT AGE TO NARROW PENSION GAP: THE CASE OF CHINA

2019 ◽  
pp. 1-21
Author(s):  
YALI LIU ◽  
MEIYING YANG ◽  
HAITAO ZHENG ◽  
YUNYUN JIANG ◽  
DONGFANG GU
Keyword(s):  
Life Expectancy ◽  
Empirical Studies ◽  
Closed Form Solution ◽  
Form Solution ◽  
Retirement Age ◽  
Retirement Benefits ◽  
Flexible Retirement ◽  
The Future ◽  
Incentive Strategies ◽  
Pension Benefits

With the relatively fixed retirement age, the dramatic increase in life expectancy and the sharp decline in fertility have caused a serious aging problem and an unsustainable pension crisis. It is therefore necessary to design flexible retirement benefits rules that consider life expectancy. By introducing the lifetime utility optimization model, the closed-form solution for the flexible retirement age is obtained. Pension benefits incentive strategies are constructed to encourage contributors to choose a retirement age that is beneficial toward narrowing the pension gap. The empirical studies show that China will face a serious pension gap in the future if the current statutory retirement age is not adjusted. If the retirement age is delayed according to life expectancy, the future pension gap will be greatly reduced.

scholarly journals Demand response based on voluntary time-dependent pricing scheme

2014 ◽  
Vol 3 ◽  
Author(s):  
Haiyan Shu ◽  
Wenxian Yang ◽  
Chin Choy Chai ◽  
Rongshan Yu
Keyword(s):  
Demand Response ◽  
Smart Grids ◽  
Large Scale ◽  
Cost Minimization ◽  
Closed Form Solution ◽  
Form Solution ◽  
Time Dependent ◽  
Generation Cost ◽  
Utility Companies ◽  
Cost Minimization Problem

With the introduction of enhanced metering and communication capabilities in smart grids, utility companies will have the ability to extend Demand Response (DR) to small customers through Time-Dependent Pricing (TDP). By using pricing signals that more accurately reflect the demand-supply situation of an electricity network, utility companies can induce customers to shift their consumptions to off-peak periods, thus reducing the cost and improving the reliability of the network. Despite its promises, large scale deployment of DR still faces many obstacles, in particular, resistance from customers due to concerns over cost, uncertain price and privacy issues. In this paper, we propose a dual-price DR scheme to overcome some of these issues. The proposed scheme offers both regulated flat price and TDP to customers to meet their different risk-taking profiles. The TDP rates are computed from a cost minimization problem considering both consumption behaviours of customers and generation cost. We also present an analysis for solving the optimization problem and find a closed form solution for TDP. It is shown that the proposed scheme is effective in inducing the desired consumption behaviours. In addition, it is found that with proper price signals, the proposed scheme can provide incentives to both utility companies and TDP customers, thus encouraging the adoption of TDP. Theoretical results from this paper are illustrated using numerical examples.

scholarly journals Rate Adaption for Secure HARQ-CC System with Multiple Eavesdroppers

Entropy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 403
Author(s):  
Yue Wu ◽  
Shishu Yin ◽  
Jian Zhou ◽  
Pei Yang ◽  
Hongwen Yang
Keyword(s):  
Outage Probability ◽  
Performance Metrics ◽  
Optimization Problems ◽  
Closed Form Solution ◽  
Information Leakage ◽  
Code Rate ◽  
Form Solution ◽  
Secrecy Outage Probability ◽  
Secrecy Outage ◽  
Iterative Optimization Algorithm

In this paper, we studied the secure transmission of a hybrid automatic repeat request with chase combining (HARQ-CC) system, under the existence of multiple eavesdroppers and limited latency. First, we analyzed some critical performance metrics, including connection outage probability (COP), secrecy outage probability (SOP) and effective secrecy throughput (EST). Then, to maximize the EST, three optimization problems of rate adaption were discussed: (i) optimizing the code rate with a given secrecy redundancy rate by a parameterized closed-form solution; (ii) optimizing the secrecy redundancy rate with a given code rate by a fixed-point method; (iii) optimizing both code rate and secrecy redundancy rate by an iterative optimization algorithm. We also considered COP and SOP constraints among the problems while corresponding solutions were deduced. Finally, numerical and simulated results verified our conclusions that the approximated SOP matches well with Monte–Carlo simulation for a strict reliable constraint, and that the optimized transmitting rate enhances EST efficiently with multiple eavesdroppers and retransmissions. Moreover, the influence of the number of eavesdroppers on secrecy performance was analyzed. Briefly, secrecy performance inevitably deteriorates with increasing number of eavesdroppers due to raised information leakage.

scholarly journals Renormalization group method for Farley-Buneman fluctuations: basic results

1996 ◽  
Vol 3 (1) ◽  
pp. 41-46
Author(s):  
A. M. Hamza
Keyword(s):  
Renormalization Group ◽  
Large Scale ◽  
Closed Form Solution ◽  
Power Spectra ◽  
Random Force ◽  
Form Solution ◽  
Density Fluctuations ◽  
Group Method ◽  
Ionospheric Physics ◽  
Weakly Ionized

Abstract. Sudan and Keskinen in [1979] derived a set of equations governing the nonlinear evolution of density fluctuations in a low-pressure weakly ionized plasma driven unstable by the E x B or gradient-drift instability. This problem is of fundamental importance in ionospheric physics. The nonlinear nature of the equations makes it very hard to write a closed form solution. In this paper we propose to use "Dynamical Renormalization Group" methods to study the long-- wavelength, long-time behaviour of density correlations generated in this ionospheric plasma stirred by a Gaussian random force characterized by a correlation function (fk fk) k. The effect of the small scales on the large scale dynamics in the limit k -> 0 and infinite "Reynolds" number, can be expressed in the form of renormalized coefficients; in our case renormalized diffusion. If one assumes the power spectra to be given by the kolmogorov argument of cascading of energy, then one can not only derive a subgrid model based on the results of RNG, and this has been done by Hamza and Sudan [1995], but one can also extract the skewness of the spectra as we do in this paper.

scholarly journals Construct the closed-form solution of A-net of Petri nets by case study

2017 ◽  
Vol 9 (2) ◽  
pp. 168781401769121 ◽  
Author(s):  
Daniel Yuh Chao ◽  
Tsung Hsien Yu
Keyword(s):  
Petri Nets ◽  
Closed Form ◽  
Closed Form Solution ◽  
Form Solution ◽  
Order System ◽  
Deadlock Avoidance ◽  
Prevention Policy ◽  
Current State ◽  
The Moment

After our researches on the effect of a non-sharing resource in a kth order which is the concept of customization manufacturing, in this article we extend the research on the closed-form solution of control-related states to the so-called A-net which has one top non-sharing circle subnet connected to the idle place of left process in a deficient kth order system and is the fundamental model of different productions sharing the same common parts in manufacturing. The formulas just are depended on the parameter k and states’ function of top non-sharing circle subnet for a subclass of nets with k sharing resources. By combining the concept of the partial deadlock avoidance/prevention policy, the moment to launch resource (controller) allocation based on the current state, and the construction of closed-form solution for deficient kth order system, it can realize the concept of dynamic non-sharing processes’ allocation.

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