142 research outputs found
Industrial Air Pollution Control
Ambient air contaminants have different adverse effects on human health, environment, and structures. Some pollutions are more toxic and have unfavorable effects on workers’ and public health, for example, cyanide/isocyanide vapor produced in some processes or in burning of polyurethane compounds, which is a toxic gas that can kill or cause harms impossible to reverse. It is so necessary that air pollutants will be controlled and treatment will be provided for the workers and public who are exposed or exhausted to the environment. Industrial ventilation (general ventilation, dilution ventilation, and local exhaust ventilation) is an appropriate system to control indoor air pollutions. Local exhaust ventilation (LEV) has different segments such as hoods, fittings, collectors (air cleaners), stacks, and fans that could collect and treat indoor and outdoor air contaminants. Each well-designed segment of a local exhaust ventilation is a vital subject that can cause an appropriate or inappropriate performance of systems. A well-designed LEV can lead to obtain a high efficiency level of pollution removal and minimum exposure (workers, public, and environment) to pollutants and save costs and energy
A Comparative Study on Using Meta-Heuristic Algorithms for Road Maintenance Planning: Insights from Field Study in a Developing Country
Optimized road maintenance planning seeks for solutions that can minimize the life-cycle cost of a road network and concurrently maximize pavement condition. Aiming at proposing an optimal set of road maintenance solutions, robust meta-heuristic algorithms are used in research. Two main optimization techniques are applied including single-objective and multi-objective optimization. Genetic algorithms (GA), particle swarm optimization (PSO), and combination of genetic algorithm and particle swarm optimization (GAPSO) as single-objective techniques are used, while the non-domination sorting genetic algorithm II (NSGAII) and multi-objective particle swarm optimization (MOPSO) which are sufficient for solving computationally complex large-size optimization problems as multi-objective techniques are applied and compared. A real case study from the rural transportation network of Iran is employed to illustrate the sufficiency of the optimum algorithm. The formulation of the optimization model is carried out in such a way that a cost-effective maintenance strategy is reached by preserving the performance level of the road network at a desirable level. So, the objective functions are pavement performance maximization and maintenance cost minimization. It is concluded that multi-objective algorithms including non-domination sorting genetic algorithm II (NSGAII) and multi-objective particle swarm optimization performed better than the single objective algorithms due to the capability to balance between both objectives. And between multi-objective algorithms the NSGAII provides the optimum solution for the road maintenance planning. © 2017 The Authors
Semantic Multi-Resolution Communications
Deep learning based joint source-channel coding (JSCC) has demonstrated
significant advancements in data reconstruction compared to separate
source-channel coding (SSCC). This superiority arises from the suboptimality of
SSCC when dealing with finite block-length data. Moreover, SSCC falls short in
reconstructing data in a multi-user and/or multi-resolution fashion, as it only
tries to satisfy the worst channel and/or the highest quality data. To overcome
these limitations, we propose a novel deep learning multi-resolution JSCC
framework inspired by the concept of multi-task learning (MTL). This proposed
framework excels at encoding data for different resolutions through
hierarchical layers and effectively decodes it by leveraging both current and
past layers of encoded data. Moreover, this framework holds great potential for
semantic communication, where the objective extends beyond data reconstruction
to preserving specific semantic attributes throughout the communication
process. These semantic features could be crucial elements such as class
labels, essential for classification tasks, or other key attributes that
require preservation. Within this framework, each level of encoded data can be
carefully designed to retain specific data semantics. As a result, the
precision of a semantic classifier can be progressively enhanced across
successive layers, emphasizing the preservation of targeted semantics
throughout the encoding and decoding stages. We conduct experiments on MNIST
and CIFAR10 dataset. The experiment with both datasets illustrates that our
proposed method is capable of surpassing the SSCC method in reconstructing data
with different resolutions, enabling the extraction of semantic features with
heightened confidence in successive layers. This capability is particularly
advantageous for prioritizing and preserving more crucial semantic features
within the datasets
Risk factors of HBs Ag positive in blood donors of Hamedan, Iran
Background: Viral hepatitis B is a common community acquired infection. It damages the liver tissue and can be a risk factor for cirrhosis and liver cancer. In the present study, we investigated the major risk factors for being HBs Ag positive among blood donors of Hamedan, Iran.Methods: A cross-sectional study was carried out in Hamedan city. All of the blood donors in Blood Transfusion Organization Center of the city were asked to fill out a questionnaire between September 2011 and February 2012. Logistic regression was used to calculate Odds Ratios (OR) for risk factors of being HBs Ag positive using IBM SPSS Statistics for Windows, Version 22.0.Results: Among 571 participants 119 (20.8%) were HBs Ag positive. Of all patients, 158 (27.6%) were female, 506 (88.6%) were living in urban areas. Also, 375 (65.7%) were married. Among the potential risk factors of HBs Ag positivity studied, “History of Surgery” ranked first (OR=3.11 P=0.003) and “Familial History of Liver Disease” was the second significant risk factor (OR=2.90 P=0.013). Human bite, dental filling, and needle stick had odds ratios less than one. However, they were not found to be statistically significant (P>0.05).Conclusion: Of all risk factors investigated in the present study, “History of Surgery” suggests a risk of infection transmission through surgical team. More studies on different populations are needed due to regional characteristics of hepatitis transmission
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