An Enhanced Two Stage MMSE Equalizer for Coded FBMC/OQAM Systems

2019 ◽  
Vol 10 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Mohammad Rizk Assaf ◽  
Abdel-Nasser Assimi
Keyword(s):  
Error Propagation ◽  
Channel Model ◽  
Error Correcting Codes ◽  
Two Stage ◽  
Probability Of Error ◽  
Second Stage ◽  
Different Types ◽  
Mmse Equalizer ◽  
And Performance ◽  
Ici Cancellation

In this article, the authors investigate the enhanced two stage MMSE (TS-MMSE) equalizer in bit-interleaved coded FBMC/OQAM system which gives a tradeoff between complexity and performance, since error correcting codes limits error propagation, so this allows the equalizer to remove not only ICI but also ISI in the second stage. The proposed equalizer has shown less design complexity compared to the other MMSE equalizers. The obtained results show that the probability of error is improved where SNR gain reaches 2 dB measured at BER compared with ICI cancellation for different types of modulation schemes and ITU Vehicular B channel model. Some simulation results are provided to illustrate the effectiveness of the proposed equalizer.

A novel two-stage method of plant seedlings classification based on deep learning

2021 ◽  
pp. 1-11
Author(s):  
Tianhong Dai ◽  
Shijie Cong ◽  
Jianping Huang ◽  
Yanwen Zhang ◽  
Xinwang Huang ◽  
...  
Keyword(s):  
Deep Learning ◽  
Learning Technology ◽  
Two Stage ◽  
Second Stage ◽  
Stage Classification ◽  
Different Types ◽  
Two Stages ◽  
Plant Seedlings

In agricultural production, weed removal is an important part of crop cultivation, but inevitably, other plants compete with crops for nutrients. Only by identifying and removing weeds can the quality of the harvest be guaranteed. Therefore, the distinction between weeds and crops is particularly important. Recently, deep learning technology has also been applied to the field of botany, and achieved good results. Convolutional neural networks are widely used in deep learning because of their excellent classification effects. The purpose of this article is to find a new method of plant seedling classification. This method includes two stages: image segmentation and image classification. The first stage is to use the improved U-Net to segment the dataset, and the second stage is to use six classification networks to classify the seedlings of the segmented dataset. The dataset used for the experiment contained 12 different types of plants, namely, 3 crops and 9 weeds. The model was evaluated by the multi-class statistical analysis of accuracy, recall, precision, and F1-score. The results show that the two-stage classification method combining the improved U-Net segmentation network and the classification network was more conducive to the classification of plant seedlings, and the classification accuracy reaches 97.7%.

Treatment of gypsum waste in a two stage anaerobic reactor

1996 ◽  
Vol 34 (5-6) ◽  
pp. 367-374 ◽  
Author(s):  
S. Deswaef ◽  
T. Salmon ◽  
S. Hiligsmann ◽  
X. Taillieu ◽  
N. Milande ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Consumption Rate ◽  
Activity Levels ◽  
Two Stage ◽  
Anaerobic Reactor ◽  
Sulphate Reducing Bacteria ◽  
Second Stage ◽  
Different Types ◽  
High Concentrations ◽  
Reducing Bacteria

The reduction of high concentrations of gypsum (up to 110 kg/m3) is investigated in a two stage immobilised cell bioreactor. The first stage is mainly colonised by a consortium of acidogenic bacteria and sulphate reducing bacteria oxidising volatile fatty acids with more than 2 carbons (mainly, butyrate and propionate). The gypsum consumption rate is rather high (11 kg/m3.day). Most of acetate remains unconverted in this first stage. It is partially converted in the second stage (residence time : 12 days) which is predominantly colonised by acetate oxidising bacteria. The gypsum consumption rate is much lower than in the first stage: 3 kg/m3.day. With both stages, it is possible to reach an almost complete conversion of gypsum with an overall capacity of 6.1 kg gypsum/m3.day. We propose also a very simple model to describe the different transformation rates. It allows us to clearly identify the activity levels of the different types of sulphate reducing bacteria in both stages.

Dynamic Modelling and Performance of a Two Stage Piezoelectric Servovalve

2016 ◽  
Author(s):  
Johan Persson ◽  
Andrew R. Plummer ◽  
Christopher R. Bowen ◽  
Phil L. Elliott
Keyword(s):  
Closed Loop ◽  
Dynamic Modelling ◽  
Flow Characteristics ◽  
The Other ◽  
Step Response ◽  
Hydraulic Fluid ◽  
Two Stage ◽  
Second Stage ◽  
And Performance ◽  
Spool Valve

This paper describes the design, simulation and testing of a piezoelectrically-actuated two stage spool valve. The first stage is a small spool controlled by a piezoelectric ring bender and the second stage is a closed loop position controlled main spool. A dynamic mathematical model of the valve has been derived. Step response tests for both the first stage and second stage are presented, and experimental second stage frequency response results are shown. The mathematical models for the amplifier, first stage and second stage spool behaviour are validated against experimental data. The second stage spool behaviour is found to be very sensitive to the first stage flow characteristics. In addition, the displacement of the hydraulic fluid by the piezoelectric ring bender, from one side of the piezoelectric ring bender to the other, had a significant impact on the valve characteristics.

Revisiting Ellsberg’s and Machina’s Paradoxes: A Two-Stage Evaluation Model Under Ambiguity

2021 ◽  
Author(s):  
Ying He
Keyword(s):  
Decision Making ◽  
Model Uncertainty ◽  
Evaluation Model ◽  
Subjective Expected Utility ◽  
Uncertainty Aversion ◽  
Two Stage ◽  
Second Stage ◽  
Different Types ◽  
Small Domain ◽  
Different Sources

In this paper, a two-stage evaluation (TSE) model for decision making under ambiguity is proposed. Events in state space are classified into risky and ambiguous events, which correspond to different types of uncertainty generated by different sources. In this TSE model, uncertainty of two different types are evaluated by decision maker (DM) in different stages. In the first stage, DM evaluates more uncertain consequences of an act locally by applying local subjective expected utility (SEU) models, which are then embedded into the second-stage evaluation based on SEU defined globally over all events. To axiomatize such a model, the small domain SEU over risky acts is extended to both risky and nonrisky (ambiguous) acts. When evaluating a risky act, TSE model reduces to Savage’s SEU with one stage. When evaluating an ambiguous act, local SEU with a different uncertainty aversion defined on ambiguous events gives TSE model some flexibility in describing preferences. It can be shown that TSE model can accommodate Ellsberg’s paradoxes and Machina’s paradoxes in the literature. When applied to portfolio selection problem, TSE model enjoys some nice properties other models do not have. This paper was accepted by Manel Baucells, decision analysis.

Effects of Multiblocking and Axial Gap Distance on Performance of Partial Admission Turbines: A Numerical Analysis

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Narmin Baagherzadeh Hushmandi ◽  
Torsten H. Fransson
Keyword(s):  
Rotor Blades ◽  
Test Case ◽  
Two Stage ◽  
Second Stage ◽  
Partial Admission ◽  
Flow Interactions ◽  
Single Arc ◽  
And Performance ◽  
Stage Efficiency ◽  
Better Than

In this paper, the effects of axial gap distance between the first stage stator and rotor blades and multiblocking on aerodynamics and performance of partial admission turbines are analyzed numerically. The selected test case is a two stage axial steam turbine with low reaction blades operating with compressed air. The multiblocking effect is studied by blocking the inlet annulus of the turbine in a single arc and in two opposing blocked arcs, each having the same admission degree. The effect of axial gap distance between the first stage stator and rotor blades is studied while varying the axial gap by 20% compared with the design gap distance. Finally, full admission turbine is modeled numerically for comparison. Performance of various computational cases showed that the first stage efficiency of the two stage partial admission turbine with double blockage was better than that of the single blockage turbine; however, the extra mixing losses of the double blockage turbine caused the efficiency to deteriorate in the downstream stage. It was shown that the two stage partial admission turbine with smaller axial gap than the design value had better efficiency of the first stage due to lower main flow and leakage flow interactions; however, the efficiency at the second stage decreased faster compared with the other cases. Numerical computations showed that the parameters, which increased the axial force of the first stage rotor wheel for the partial admission turbine, were longer blocked arc, single blocked arc, and reduced axial gap distance between the first stage stator and rotor blades.

scholarly journals Sidik-Chaula Urethroplasty and the Manset Flap for Non-Glanular Hypospadias Repair

1970 ◽  
Vol 1 (1) ◽  
Author(s):  
Chaula L Sukasah ◽  
Laureen Supit
Keyword(s):  
Postoperative Complications ◽  
Primary Repair ◽  
Hypospadias Repair ◽  
Operative Techniques ◽  
Two Stage ◽  
Simple Modification ◽  
Second Stage ◽  
Different Types ◽  
The One ◽  
Rate Of Success

Hypospadias present with a wide array of meatal position and curvature. Choosing an operative technique for the different types of hypospadias has been challenging and controversial among the plastic, urologic, and pediatric surgeons. Regardless of the selected techniques, primary hypospadias repair still frequently results in complications requiring further surgery, such as fistula, residual chordee, and stricture. Owing to its practicality, the single stage urethroplasties are more-popular and widely used at present. However, our experience found higher rates of postoperative complications with the one-stage procedure compared to the two-stage for repair of non-glanular hypospadia. This article details the operative techniques of the two-stage Sidik-Chaula urethroplasty, a technique that we have implemented in our institution over two decades. It is applicable for the primary repair of any distal, middle, and proximal hypospadias. We also introduce the Manset Flap, a simple modification to the first stage of urethroplasty, which ease neourethra creation in the second stage. However, due to prior insufficient medical recordkeeping, we are yet unable to produce a quantified rate of success and complications by utilizing this technique. A study is currently being done to produce the numbers.

A Two-Stage Hybrid Heuristic for Vehicle Routing Problem with Fuzzy Demands

2011 ◽  
Vol 460-461 ◽  
pp. 710-715 ◽  
Author(s):  
Chang Shi Liu ◽  
Fu Hua Huang
Keyword(s):  
Vehicle Routing ◽  
Vehicle Routing Problem ◽  
Credibility Measure ◽  
Computational Results ◽  
Two Stage ◽  
Routing Problem ◽  
Hybrid Heuristic ◽  
Second Stage ◽  
Hybrid Heuristics ◽  
And Performance

A two-stage hybrid heuristic is presented for vehicle routing problem with fuzzy demands in this paper, the fuzzy credibility measure is employed to determine the credibility to send the vehicle to next node in the first stage, and a hybrid heuristics is proposed to determine a set of vehicle routes to minimize total costs in the second stage, especially for the additional distance and additional loading times. Finally the computational results are presented to show the high effectiveness and performance of the proposed approaches.

Characteristics of Physicians Referred for a Competence Assessment: A Comparison of State Medical Board and Hospital Referred Physicians

2010 ◽  
Vol 96 (3) ◽  
pp. 8-15 ◽  
Author(s):  
Elizabeth S. Grace ◽  
Elizabeth J. Korinek ◽  
Zung V. Tran
Keyword(s):  
Clinical Competence ◽  
Competence Assessment ◽  
Average Performance ◽  
Medical Board ◽  
Key Characteristics ◽  
Different Types ◽  
Specialty Board ◽  
And Performance ◽  
State Medical Boards ◽  
State Medical Board

ABSTRACT This study compares key characteristics and performance of physicians referred to a clinical competence assessment and education program by state medical boards (boards) and hospitals. Physicians referred by boards (400) and by hospitals (102) completed a CPEP clinical competence assessment between July 2002 and June 2010. Key characteristics, self-reported specialty, and average performance rating for each group are reported and compared. Results show that, compared with hospital-referred physicians, board-referred physicians were more likely to be male (75.5% versus 88.3%), older (average age 54.1 versus 50.3 years), and less likely to be currently specialty board certified (80.4% versus 61.8%). On a scale of 1 (best) to 4 (worst), average performance was 2.62 for board referrals and 2.36 for hospital referrals. There were no significant differences between board and hospital referrals in the percentage of physicians who graduated from U.S. and Canadian medical schools. The most common specialties referred differed for boards and hospitals. Conclusion: Characteristics of physicians referred to a clinical competence program by boards and hospitals differ in important respects. The authors consider the potential reasons for these differences and whether boards and hospitals are dealing with different subsets of physicians with different types of performance problems. Further study is warranted.

Personalised attraction recommendation for enhancing topic diversity and accuracy

2021 ◽  
pp. 016555152199980
Author(s):  
Yuanyuan Lin ◽  
Chao Huang ◽  
Wei Yao ◽  
Yifei Shao
Keyword(s):  
Real World ◽  
Information Overload ◽  
Two Stage ◽  
Misclassification Cost ◽  
Second Stage ◽  
Low Visibility ◽  
Recommendation Diversity ◽  
Optimisation Model ◽  
Definition Of ◽  
Improved Methods

Attraction recommendation plays an important role in tourism, such as solving information overload problems and recommending proper attractions to users. Currently, most recommendation methods are dedicated to improving the accuracy of recommendations. However, recommendation methods only focusing on accuracy tend to recommend popular items that are often purchased by users, which results in a lack of diversity and low visibility of non-popular items. Hence, many studies have suggested the importance of recommendation diversity and proposed improved methods, but there is room for improvement. First, the definition of diversity for different items requires consideration for domain characteristics. Second, the existing algorithms for improving diversity sacrifice the accuracy of recommendations. Therefore, the article utilises the topic ‘features of attractions’ to define the calculation method of recommendation diversity. We developed a two-stage optimisation model to enhance recommendation diversity while maintaining the accuracy of recommendations. In the first stage, an optimisation model considering topic diversity is proposed to increase recommendation diversity and generate candidate attractions. In the second stage, we propose a minimisation misclassification cost optimisation model to balance recommendation diversity and accuracy. To assess the performance of the proposed method, experiments are conducted with real-world travel data. The results indicate that the proposed two-stage optimisation model can significantly improve the diversity and accuracy of recommendations.

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