scholarly journals Cost optimization of two-stage helical gearboxes with second stage double gear-sets

2021 ◽  
pp. 89-101
Author(s):  
Le Hoang Anh ◽  
Nguyen Hong Linh ◽  
Nguyen Huu Quang ◽  
Pham Duc Lam ◽  
Nguyen Anh Tuan ◽  
...  
Keyword(s):  
Contact Stress ◽  
Cost Optimization ◽  
Transmission Ratio ◽  
Two Stage ◽  
Effective Measure ◽  
Second Stage ◽  
Face Width ◽  
Screening Experiments ◽  
Input Parameters ◽  
The Cost

In practice, the cost of a gearbox plays a very important role in the trade. Therefore, reducing the cost of gearboxes is an important task not only when manufacturing the gearboxes but also when designing them. In order to reduce the cost of a gearbox, there are many solutions in which determining the optimal partial gear ratios of a gearbox is an effective measure. This is because it not only the size, the mass but also the cost of a gearbox depends greatly on the partial gear ratios. This work presents a method for calculating the cost function of two-stage helical gearboxes with second-stage double gear-sets based on the mass of the components that construct the gearbox. The cost objective function is minimized to achieve the optimal transmission ratios. Furthermore, screening experiments are carried out with nine important input parameters that have significant effects on the optimum transmission ratio of the second stage. These parameters are the total gearbox ratio, the coefficient of wheel face width of the first stage, coefficient of wheel face width of the second stage, the allowable contact stress of the first stage, the allowable contact stress of the second stage, the output torque, the cost of gearbox housing, the cost of gears, and the shaft cost. The experimental results of were analysed by using the Analysis of Variance (ANOVA) method with the help of Minitab 19 software. The results demonstrate that the effective weight of the input parameters and their interactions on the output response was investigated. Also, a regression model for computing the optimal transmission ratio of the second stage was proposed. This brings significance not only in the design process but also in manufacturing since the gearbox cost can decrease

Preparing a framework for two-stage target-cost arrangement formulation

2016 ◽  
Vol 9 (1) ◽  
pp. 123-146 ◽  
Author(s):  
Pertti Lahdenperä
Keyword(s):  
Service Provider ◽  
Development Process ◽  
Cost Effective ◽  
Two Stage ◽  
Content Type ◽  
Investment Projects ◽  
Second Stage ◽  
Target Cost ◽  
The Cost ◽  
Concrete Model

Purpose – Early involvement of the project team with the construction resources seems to be gaining popularity as it aims to improve the cost efficiency of a project as there is significantly more potential to influence the project solution at that point in time. The missing price during early involvement/selection and the principal-agent setting, however, tend to leave the project owner in doubt of the reasonableness of pricing when it is fixed only later after the joint design phase involving the service provider and the owner. The purpose of this paper is to find a solution for this challenge. Design/methodology/approach – A two-stage target-cost (2STC) arrangement has been proposed as the solution. In this model the service provider earns a bonus by suggesting a lower target cost than the reference set at the time of the involvement of the provider. The amount of bonus also impacts the cost over-run risk transferred to the service provider to avoid overly optimistic promises. The proposition encompassed just the basic idea, and did not really delve into actual model formulations and their functioning under practical realities. Therefore, the required work is presented here in the form of a conceptual, discursive study focusing on relevant theories and empirical findings from major investment projects. Findings – The study produces a requirement framework for the 2STC model to allow functioning models to be formulated and tested. The framework incorporates numerous requirements, constraints and a suggested path forward. For instance, while the model may not be manipulatable, it must incentivise the service provider to seek more cost-effective project solutions, be feasible also from the view of the project owner and adapt to various project risk profiles and ranges of efficiency improvements. Research limitations/implications – The study suggests more concrete model formulations to be provided under the guidance of the presented framework. Originality/value – The 2STC model is a unique concept and no comparable construct is known to exist. Besides the requirement framework, the study also strengthens the foundation of and need for the 2STC model by a thorough survey of its theoretical linkages. Accordingly, the study presented in this paper forms the second stage in the overall 2STC development process focused on benefiting project owners and the industry.

The Damage Inspection and Safety Assessment on Steel-Sheet Pile Wharf Structural System

2006 ◽  
Vol 324-325 ◽  
pp. 1221-1224 ◽  
Author(s):  
H.H. Lee ◽  
P.Y. Chang
Keyword(s):  
Safety Assessment ◽  
Steel Sheet ◽  
Structural System ◽  
Sheet Pile ◽  
Two Stage ◽  
Second Stage ◽  
Inspection Strategy ◽  
Pile Type ◽  
The Cost

This study proposes a procedure of damage inspection for the infrastructure in the harbor. Because most infrastructures in the harbor are submerged under the water the damage inspection is very difficult to process. Normally, divers with special scheme of damage inspection are required and the cost is very expensive. Therefore, a two-stage inspection strategy is proposed. After the first stage of inspection the more detailed second stage inspection will be requested dependent on the examination results. In the second stage of inspection particularly, it is focused on the wharf structures of steel-sheet pile type, where the related items are identified corresponding to the characteristics of the structural system.

HELPING AND SABOTAGING IN TOURNAMENTS

2005 ◽  
Vol 07 (02) ◽  
pp. 211-228 ◽  
Author(s):  
MATTHIAS KRÄKEL
Keyword(s):  
The Other ◽  
Two Stage ◽  
Second Stage ◽  
Asymmetric Equilibria ◽  
The Cost ◽  
Cost Effect

A two-stage, two-person tournament is discussed, in which each player can influence the other one at the first stage by choosing help, sabotage or no action. At the second stage, the players choose effort to win the tournament. Helping and sabotaging have two effects — they influence the likelihood of winning (likelihood effect) and they determine the equilibrium efforts and, therefore, effort costs (cost effect). Depending on the interplay of the two effects, diverse types of equilibria are possible. In particular, if the cost effect dominates the likelihood effect (i.e., both players concentrate on minimizing effort costs), two asymmetric equilibria will coexist in which one player helps his opponent, whereas the other one chooses sabotage and vice versa.

scholarly journals The Influence of Main Design Parameters on the Overall Cost of a Gearbox

2020 ◽  
Vol 10 (7) ◽  
pp. 2365 ◽  
Author(s):  
Ngoc-Pi Vu ◽  
Dinh-Ngoc Nguyen ◽  
Anh-Tung Luu ◽  
Ngoc-Giang Tran ◽  
Thi-Hong Tran ◽  
...  
Keyword(s):  
Simulation Experiment ◽  
Cost Optimization ◽  
Design Parameters ◽  
Regression Equations ◽  
Main Design ◽  
Optimization Program ◽  
The Third ◽  
Input Parameters ◽  
The Cost ◽  
Total Ratio

This study is aimed at determining optimum partial gear ratios to minimize the cost of a three-stage helical gearbox. In this work, eleven input parameters were investigated to find their influence on the optimum gear ratios of the second and the third stages ( u 2 and u 3 ). To reach the goal, a simulation experiment was designed and implemented by a cost optimization program. The results revealed that in addition to the input parameters, their interactions also have important effects in which the total ratio gearbox ratio ( u t ) and the cost of shaft ( C s ) have the most impact on u 2 and u 3 responses, respectively. Moreover, the proposed models of the two responses are highly consistent to the experimental results. The proposed regression equations can be applied to solve optimization cost problems.

Polyethylene on Cement Spacers: An Economic Approach to an Effective Infection Eradication in a Two-Stage Knee Revision Articulating Spacers

2018 ◽  
Vol 31 (10) ◽  
pp. 986-991
Author(s):  
Junren Lu ◽  
Jing Han ◽  
Zhenjun Yao ◽  
Yi Yang ◽  
Chi Zhang
Keyword(s):  
Revision Surgery ◽  
Joint Infection ◽  
Cost Effective ◽  
Two Stage ◽  
Second Stage ◽  
Articulating Spacer ◽  
Eradication Of Infection ◽  
Total Knee ◽  
The Cost

AbstractAlthough two-stage revision surgery is generally considered as the gold standard treatment for periprosthetic joint infection (PJI) after total knee arthroplasty, the procedure is limited by the costs of commercially preformed spacers used for treatment. In this work, we aim to report a modified approach by which the cost of the spacer could be significantly reduced without compromising eradication of infection. Between 2010 and 2016, we performed a total of 11 two-stage revision arthroplasties using a surgically handmade spacer with a new polyethylene insert. Patients were aged 59 to 80 years old (mean 69.9 years), with a range of motion (ROM) between 20° and 65° on the affected knee (mean 46.4°) before the first-stage revision surgery. During the perioperative and postoperative period, functional and clinical evaluation of the patients were performed, including the determination of their articular ROM, Knee Society Knee Scores (KSKS), and Knee Society Function Scores (KSFS). All patients were followed up for an average of 2 years, ranging from 1 to 4 years. After the second-stage revision surgery, the mean ROM was increased by 46.8° (46.4°–93.2°) after the second-stage revision. KSKS and KSFS scores were recorded to increase by an average of 44.5° (range 40.4°–84.9°) and 46.9° (range 38.5°–85.4°), respectively. All 11 patients underwent a successful two-stage revision surgery, and no evidence of postsurgical infection was found during patient follow-up examination. Our results show that this personalized handmade antibiotic-loaded articulating spacer is cost-effective and efficacious.

Meshing and Bearing Analysis of Nutation Drive with Face Gear

2020 ◽  
Vol 13 (4) ◽  
pp. 352-365
Author(s):  
Guangxin Wang ◽  
Lili Zhu ◽  
Peng Wang ◽  
Jia Deng
Keyword(s):  
Contact Stress ◽  
High Efficiency ◽  
Transmission Ratio ◽  
Contact Strength ◽  
Hertz Contact ◽  
Face Gear ◽  
Compact Structure ◽  
Gear Teeth ◽  
Gear Drive ◽  
Number Of Teeth

Background: Nutation drive is being extensively investigated due to its ability to achieve a high reduction ratio with a compact structure and the potential for low vibration, high efficiency and design flexibility. However, many problems including the difficulty to process the inner bevel gear, less number of teeth in engagement and not being suitable for high-power transmission have restricted its development. Objective: The purpose of this paper is to analyze the contact strength of a patent about a new nutation drive developed based on meshing between two face gears, which has the advantages of both face gear and nutation drive, including large transmission ratio, large coincidence, small size, compact structure and strong bearing capacity. Methods: Based on the meshing principle and basic structure of the nutation face gear drive, the contact strength of nutation face gear transmission is analyzed by the Hertz contact analysis method and FEM method. Results: The maximum stress values of nutation face gear teeth are compared by two methods, which verify the accuracy of Hertz contact analytical method in calculating the contact strength of nutation face gear teeth. Furthermore, nine groups of three-dimensional models for the nutation face gear drive with a transmission ratio of 52 and different cutter parameters are established. Conclusion: The study analyzes the contact stress of fixed and rotary face gears in meshing with planetary face gears, and obtains the distribution law of contact stress and the influence of the number of teeth and parameters of the cutter on the load-carrying capacity.

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.

scholarly journals Cost-Effectiveness of an Exercise Programme that Provided Group or Individual Training to Reduce the Fall Risk in Healthy Community-Dwelling People Aged 65–80: A Secondary Data Analysis

Healthcare ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 714
Author(s):  
Isaac Aranda-Reneo ◽  
Laura Albornos-Muñoz ◽  
Manuel Rich-Ruiz ◽  
María Ángeles Cidoncha-Moreno ◽  
Ángeles Pastor-López ◽  
...  
Keyword(s):  
Economic Evaluation ◽  
Cost Effectiveness ◽  
Older People ◽  
Incremental Cost ◽  
Fall Risk ◽  
Community Dwelling ◽  
Effective Measure ◽  
The Individual ◽  
The Cost ◽  
Individual Training

Research has demonstrated that some exercise programs are effective for reducing fall rates in community-dwelling older people; however, the literature is limited in providing clear recommendations of individual or group training as a result of economic evaluation. The objective of this study was to assess the cost-effectiveness of the Otago Exercise Program (OEP) for reducing the fall risk in healthy, non-institutionalized older people. An economic evaluation of a multicenter, blinded, randomized, non-inferiority clinical trial was performed on 498 patients aged over 65 in primary care. Participants were randomly allocated to the treatment or control arms, and group or individual training. The program was delivered in primary healthcare settings and comprised five initial sessions, ongoing encouragement and support to exercise at home, and a reinforcement session after six months. Our hypothesis was that the patients who received the intervention would achieve better health outcomes and therefore need lower healthcare resources during the follow-up, thus, lower healthcare costs. The primary outcome was the incremental cost-effectiveness ratio, which used the timed up and go test results as an effective measure for preventing falls. The secondary outcomes included differently validated tools that assessed the fall risk. The cost per patient was USD 51.28 lower for the group than the individual sessions in the control group, and the fall risk was 10% lower when exercises had a group delivery. The OEP program delivered in a group manner was superior to the individual method. We observed slight differences in the incremental cost estimations when using different tools to assess the risk of fall, but all of them indicated the dominance of the intervention group. The OEP group sessions were more cost-effective than the individual sessions, and the fall risk was 10% lower.

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.

scholarly journals Two-stage multi-tasking transform framework for large-scale many-objective optimization problems

2021 ◽  
Author(s):  
Lu Chen ◽  
Handing Wang ◽  
Wenping Ma
Keyword(s):  
Large Scale ◽  
Original Problem ◽  
Optimization Problems ◽  
Reference Points ◽  
Optimization Strategy ◽  
Two Stage ◽  
Decision Space ◽  
Second Stage ◽  
Decision Variables ◽  
Objective Space

AbstractReal-world optimization applications in complex systems always contain multiple factors to be optimized, which can be formulated as multi-objective optimization problems. These problems have been solved by many evolutionary algorithms like MOEA/D, NSGA-III, and KnEA. However, when the numbers of decision variables and objectives increase, the computation costs of those mentioned algorithms will be unaffordable. To reduce such high computation cost on large-scale many-objective optimization problems, we proposed a two-stage framework. The first stage of the proposed algorithm combines with a multi-tasking optimization strategy and a bi-directional search strategy, where the original problem is reformulated as a multi-tasking optimization problem in the decision space to enhance the convergence. To improve the diversity, in the second stage, the proposed algorithm applies multi-tasking optimization to a number of sub-problems based on reference points in the objective space. In this paper, to show the effectiveness of the proposed algorithm, we test the algorithm on the DTLZ and LSMOP problems and compare it with existing algorithms, and it outperforms other compared algorithms in most cases and shows disadvantage on both convergence and diversity.

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