Limited-Knowledge Economic Dispatch Prediction using Bayesian Averaging of Single-Node Models

2018 ◽  
Author(s):  
Kevin D. Smith ◽  
Karen Studarus
Keyword(s):  
Economic Dispatch ◽  
Single Node ◽  
Limited Knowledge ◽  
Bayesian Averaging

An Accelerated Cue Combination Principle Accounts for Multi-cue Depth Perception

2020 ◽  
Vol 3 (1) ◽  
pp. 10501-1-10501-9
Author(s):  
Christopher W. Tyler
Keyword(s):  
Belief Propagation ◽  
Probability Distributions ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Fusion Model ◽  
Cue Combination ◽  
Depth Estimate ◽  
Appropriate Behavior ◽  
Depth Cues ◽  
Bayesian Averaging

Abstract For the visual world in which we operate, the core issue is to conceptualize how its three-dimensional structure is encoded through the neural computation of multiple depth cues and their integration to a unitary depth structure. One approach to this issue is the full Bayesian model of scene understanding, but this is shown to require selection from the implausibly large number of possible scenes. An alternative approach is to propagate the implied depth structure solution for the scene through the “belief propagation” algorithm on general probability distributions. However, a more efficient model of local slant propagation is developed as an alternative.The overall depth percept must be derived from the combination of all available depth cues, but a simple linear summation rule across, say, a dozen different depth cues, would massively overestimate the perceived depth in the scene in cases where each cue alone provides a close-to-veridical depth estimate. On the other hand, a Bayesian averaging or “modified weak fusion” model for depth cue combination does not provide for the observed enhancement of perceived depth from weak depth cues. Thus, the current models do not account for the empirical properties of perceived depth from multiple depth cues.The present analysis shows that these problems can be addressed by an asymptotic, or hyperbolic Minkowski, approach to cue combination. With appropriate parameters, this first-order rule gives strong summation for a few depth cues, but the effect of an increasing number of cues beyond that remains too weak to account for the available degree of perceived depth magnitude. Finally, an accelerated asymptotic rule is proposed to match the empirical strength of perceived depth as measured, with appropriate behavior for any number of depth cues.

Institutional Repositories in Swaziland: An Exploratory Study

Mousaion ◽  
2019 ◽  
Vol 36 (2) ◽  
Author(s):  
Ncamsile Nombulelo Dlamini ◽  
Maritha Snyman
Keyword(s):  
Open Access ◽  
Exploratory Study ◽  
Management Strategies ◽  
Current Status ◽  
Academic Institutions ◽  
African Countries ◽  
Institutional Repositories ◽  
Limited Knowledge ◽  
Advocacy Strategies ◽  
Awareness Level

The purpose of this paper is to assess the current status of institutional repositories (IRs) in Swaziland’s academic institutions. The factors under discussion are the number of IRs in Swaziland, their usage, the level of awareness of these IRs, and the challenges that prevent the implementation of IRs in Swaziland’s academic institutions. A webometric approach, interviews and semi-structured questionnaires completed by IR managers or librarians working for the Swaziland’s academic institutions were used to collect data for this study. Responses were received from 11 respondents. The findings indicated that there is one IR in Swaziland that is accessible to the institution’s community via the intranet. This IR was, at the time when this study took place, not registered in any of the international registries of repositories, such as the Registry of Open Access Repositories (ROAR) and the Directory of Open Access Repositories (OpenDOAR). Currently, this IR faces problems of insufficient content, a low level of IR awareness, limited knowledge of effective and appropriate IR advocacy strategies and limited knowledge of effective IR implementation and management strategies. Based on the findings and information gained from a literature review of IRs, the paper recommends strategies to academic institutions in Swaziland that may enable them to increase their number of IRs, the awareness level of IRs and consequently the use of IRs. The findings and recommendations may also benefit other African countries in similar situations.  

The Economic Dispatch of Wind Integrated Power System based on an Improved Differential Evolution Algorithm

2020 ◽  
Vol 13 (3) ◽  
pp. 384-395
Author(s):  
Haiqing Liu ◽  
Jinmeng Qu ◽  
Yuancheng Li
Keyword(s):  
Differential Evolution ◽  
Artificial Bee Colony Algorithm ◽  
Artificial Bee Colony ◽  
Economic Dispatch ◽  
Differential Evolution Algorithm ◽  
Bee Colony ◽  
Evolution Algorithm ◽  
Improved Differential Evolution Algorithm ◽  
Dynamic Economic Dispatch ◽  
Integrated Power System

Background: As more and more renewable energy such as wind energy is connected to the power grid, the static economic dispatch in the past cannot meet its needs, so the dynamic economic dispatch of the power grid is imperative. Methods: Hence, in this paper, we proposed an Improved Differential Evolution algorithm (IDE) based on Differential Evolution algorithm (DE) and Artificial Bee Colony algorithm (ABC). Firstly, establish the dynamic economic dispatch model of wind integrated power system, in which we consider the power balance constraints as well as the generation limits of thermal units and wind farm. The minimum power generation costs are taken as the objectives of the model and the wind speed is considered to obey the Weibull distribution. After sampling from the probability distribution, the wind speed sample is converted into wind power. Secondly, we proposed the IDE algorithm which adds the local search and global search thoughts of ABC algorithm. The algorithm provides more local search opportunities for individuals with better evolution performance according to the thought of artificial bee colony algorithm to reduce the population size and improve the search performance. Results: Finally, simulations are performed by the IEEE-30 bus example containing 6 generations. By comparing the IDE with the other optimization model like ABC, DE, Particle Swarm Optimization (PSO), the experimental results show that obtained optimal objective function value and power loss are smaller than the other algorithms while the time-consuming difference is minor. The validity of the proposed method and model is also demonstrated. Conclusion: The validity of the proposed method and the proposed dispatch model is also demonstrated. The paper also provides a reference for economic dispatch integrated with wind power at the same time.

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