scholarly journals Semantic-Based Assembly Precision Optimization Strategy Considering Assembly Process Capacity

Machines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 269
Author(s):  
Xiaolin Shi ◽  
Xitian Tian ◽  
Gangfeng Wang ◽  
Dongping Zhao
Keyword(s):  
Optimization Method ◽  
Assembly Process ◽  
Optimization Strategy ◽  
Success Rates ◽  
Ontology Language ◽  
Key Characteristics ◽  
Fast Solution ◽  
Important Means ◽  
The One ◽  
Assembly Precision

Assembly precision optimization is an important means to ensure product accuracy, including two aspects: on the one hand, the relevant deviations of out-of-tolerance key characteristics are reduced to the design tolerance range; on the other hand, the deviation fluctuation range of key characteristics with a large process capability index (Cp) can be extended to achieve the balance between accuracy, process capacity, and production cost. By virtue of the accumulated experience, a fast solution can be provided for the out-of-tolerance problem. Therefore, a semantic-based assembly precision optimization method considering process capacity is proposed in this paper. By constructing an ontology model between Cp and optimization strategy, a reasonable assembly precision optimization strategy can be pushed based on product accuracy analysis results. Firstly, an assembly precision optimization semantic model is established by association between analysis results, out-of-tolerance key characteristics, assembly process, and tolerance adjustment defined with Web Ontology Language (OWL) assertions. Furtherly, according to different Cp corresponding to different assembly success rates, Semantics Web Rule Language (SWRL) rules based on Cp are constructed to the push optimization strategy. Finally, the effectiveness of the model is illustrated by an aircraft inner flap.

An Assembly Simulation Optimization Method Based on View Transformation

2013 ◽  
Vol 658 ◽  
pp. 455-459
Author(s):  
Jian Jun Tang ◽  
Xi Tian Tian ◽  
Jun Hao Geng ◽  
Ming Xing Bai ◽  
Xiang Wei Liu
Keyword(s):  
Coordinate System ◽  
Process Simulation ◽  
Simulation Optimization ◽  
Optimization Method ◽  
Assembly Process ◽  
System Transformation ◽  
Aircraft Assembly ◽  
Assembly Simulation ◽  
The One ◽  
View Transformation

In order to improve showing effect of the aircraft assembly simulation, a new assembly process simulation optimization method was proposed with combining evaluation of viewpoints with view transformation. First, viewpoints evaluation principle was put forward according to assembly simulation features; then a new view coordinate system was calculated based on the view coordinate system transformation matrix by integrating the direction of assembly paths with the viewpoints evaluation principle; finally, entire optimized process of assembly simulation was analyzed. Efficiency of this method was verified by comparing the result of the optimized wing box assembly simulation with the one which had not been optimized.

An Enhanced One-Layer Passive Microfluidic Mixer With an Optimized Lateral Structure With the Dean Effect

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Teng Zhou ◽  
Yifan Xu ◽  
Zhenyu Liu ◽  
Sang Woo Joo
Keyword(s):  
Reynolds Number ◽  
Topology Optimization ◽  
Optimization Method ◽  
Mixing Efficiency ◽  
Boolean Operation ◽  
Microfluidic Mixer ◽  
Wide Range ◽  
The One ◽  
Lateral Structure ◽  
Topology Optimization Method

Topology optimization method is applied to a contraction–expansion structure, based on which a simplified lateral flow structure is generated using the Boolean operation. A new one-layer mixer is then designed by sequentially connecting this lateral structure and bent channels. The mixing efficiency is further optimized via iterations on key geometric parameters associated with the one-layer mixer designed. Numerical results indicate that the optimized mixer has better mixing efficiency than the conventional contraction–expansion mixer for a wide range of the Reynolds number.

Design rules for timber log reciprocal floors, based on mass optimization under stiffness constraint

2021 ◽  
pp. 095605992110416
Author(s):  
Pierre Latteur ◽  
Julien Geno ◽  
Marie Vandamme
Keyword(s):  
Parametric Design ◽  
Optimization Method ◽  
Equilibrium Equations ◽  
Design Rules ◽  
Stiffness Optimization ◽  
Structural Relevance ◽  
Reciprocal Structures ◽  
General Mass ◽  
The One ◽  
Robotic Tools

Building with raw timber allows to reduce the price of construction and to make it more competitive with respect to concrete or steel construction. For a few years now, the combination of parametric design and robotic tools make possible the fast and precise milling of timber logs for their accurate connection. However, the spans are quickly limited by the logs length. In this context, reciprocal structures are relevant, since they allow to build large spans structures with short beams. Finally, the architectural interest of reciprocal structures is not to prove. However, the choice of the most efficient reciprocal frame, as well as its structural relevance in terms of mass and stiffness is, most of the time, ruled by subjective considerations. This paper focuses on rectangular floors composed of reciprocal moduli and has three objectives: (1) to develop a general mass and stiffness optimization method for reciprocal floors, which is not only necessary to limit the price, but also to reduce their thickness, (2) to define design rules for reciprocal floors, in particular for the choice of the best engagement ratio, and (3) to compare the structural efficiency of reciprocal floors with the one of “traditional” floors with parallel logs. Coming from a dimensionless transformation of the equilibrium equations, the results of this article will thus give the designers keys to better design reciprocal structures, evaluate their structural performances and relevance, and justify their choices.

scholarly journals SINGLE-DOSE PRULIFLOXACIN VERSUS SINGLE-DOSE PEFLOXACIN IN THE TREATMENT OF ACUTE UNCOMPLICATED URINARY TRACT INFECTION IN WOMEN

2010 ◽  
Vol 18 (3) ◽  
pp. 5
Author(s):  
M. CERVIGNI ◽  
G. ORTICELLI ◽  
M. BOLOGNA ◽  
F. NATALE ◽  
E. SALVATORI ◽  
...  
Keyword(s):  
Single Dose ◽  
Urinary Tract ◽  
Eradication Rate ◽  
Clinical Success ◽  
Therapeutic Option ◽  
Uncomplicated Urinary Tract Infection ◽  
Efficacy And Safety ◽  
Success Rates ◽  
The One ◽  
Tract Infections

The aim of the study was to compare the efficacy and safety of singledose prulifloxacin vs. single-dose pefloxacin in the treatment of patients with acute uncomplicated urinary tract infections. Two hundred and thirty-one female out-patients were considered microbiologically evaluable and randomly treated with 600 mg prulifloxacin (116 patients) or 800 mg pefloxacin (115 patients). The most commonly isolated uropathogen at baseline was Escherichia coli (71.4%), followed by Proteus mirabilis (10.8%) and Klebsiella pneumoniae (7.8%). Five-seven days posttreatment, the eradication rate was 97.4% and 92.2% in the prulifloxacin and pefloxacin group, respectively. The one-tailed 95% confidence interval analysis showed the equivalence of treatments. Four weeks from treatment no relapses, reinfections or superinfections were observed. The clinical success rates were 92.2% in the prulifloxacin and 84.3% pefloxacin groups. The safety profile was very good with both drugs. The results of the study make it possible to consider prulifloxacin a possible therapeutic option in patients with acute uncomplicated UTIs.

Comprehensive identification of aircraft coordination feature based on complete importance modeling and its engineering application

2018 ◽  
Vol 38 (4) ◽  
pp. 398-411 ◽  
Author(s):  
Feiyan Guo ◽  
Fang Zou ◽  
Jian Hua Liu ◽  
Bo Zhao ◽  
Zhongqi Wang
Keyword(s):  
Engineering Application ◽  
Laboratory Method ◽  
Correction Coefficient ◽  
Assembly Process ◽  
Quality Loss ◽  
Content Type ◽  
Aircraft Manufacturing ◽  
Close Relationship ◽  
Geometric Size ◽  
Assembly Precision

Purpose Coordination feature (CF) is the information carrier in dimension and shape transfer process in aircraft manufacturing. The change of its geometric size, shape, position or other attributes would affect the consistency of accumulated errors between two or more assemblies. To identify these “key characteristics” that have a close relationship with the assembly precision, a comprehensive method was developed under digital manufacturing environment, which was based on importance calculation. The multi-hierarchy and multi-station assembly process of aircraft products were also taken into consideration. Design/methodology/approach First, the interaction and evaluation relationship between components at different manufacturing stages was decomposed with a hierarchical net. Second, to meet coordination accuracy requirements, with the integrated application of Taguchi quality loss function, accuracy principal and error correction coefficient H, the quality loss between target features and candidate features at adjacent assembly hierarchies were calculated, which was based on their precision variation. Third, the influence degree and affected degree of the features were calculated with DEMATEL (decision-making trial and evaluation laboratory) method, and the concepts of centrality degree index and cause degree index were proposed for calculating the complete importance degree to eventually identify the CFs. Findings Based on the proposed methodology, CFs, affecting the skin profile and the flush coordination accuracy, were successfully identified at different assembly hierarchies to a certain type of wing flap component. Originality/value Benefit results for the engineering application showed that the deviation of skin profile was more accurate than before, and the tolerance was also closer to the centerline of required assembly precision range. Moreover, the stability in the assembly process was increased by 26.9 per cent, which could bring a higher assembly quality and an enhancement on aircraft’s flight performance.

scholarly journals The impact of the means of communication on family relationships

2016 ◽  
Vol 2 (3) ◽  
pp. 344
Author(s):  
Twana Faraidun Hussein
Keyword(s):  
Family Relationships ◽  
Research Community ◽  
Negative Effects ◽  
Positive Effects ◽  
Important Means ◽  
Questionnaire Form ◽  
The One ◽  
The Impact ◽  
The City ◽  
Day By Day

This research tries to access to a range of outcomes, and to answer the fundamental question, a search (What is the impact of the means of communication on family relationships?).Try researcher through the form of a questionnaire to collect information in the field of the research community and in order to achieve his goal, And it relied on the questionnaire form for being an important means used extensively in sociology studies, The center of the city of Sulaymaniyah spatial boundaries of the search, where it is taken (200) and a sample search unit and distributed to three different areas (rich, middle and poor) by taking a stratified random sample, The fact that the population of the city of Sulaymaniyah different in terms of economic and cultural level, it's easy to take the mixed researcher and different sample representing the research community in terms of level, category, and class. They were assembled for the purpose of research and study.      It must be pointed out that this research is particularly important at the present time because the means of communication have spread widely in the Kurdish community and become accessible to everyone on the one hand, on the other hand, the number of users of these methods is increasing day by day, This is in addition to the increased demand for them constantly, making conduct such research in this importance area to see its impact on family relationships, and knowledge of its money from the effects (negative and positive) It is known that this means a double-edged her weapon of negative and positive effects at the same time, It must be the effort to reduce the negative effects of these tools and become members of the community in the service, and most importantly of all, do educate individuals on how to deal with these tools properly. It also offers search a set of proposals and recommendations to the concerned authorities to work out and strengthen the community in front of the challenges of the era of globalization of communications and response, where he became the Kurdish community a society open to the outside world through these means, which resulted in a change of values and social norms and behaviors that were adhered to by members of the community.

scholarly journals Real-Time Return Demand Prediction Based on Multisource Data of One-Way Carsharing Systems

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Dongbo Liu ◽  
Jian Lu ◽  
Wanjing Ma
Keyword(s):  
Prediction Model ◽  
Real Time ◽  
Supply And Demand ◽  
Optimization Strategy ◽  
Trajectory Data ◽  
Demand Prediction ◽  
Data User ◽  
User Characteristic ◽  
Destination Station ◽  
The One

One-way carsharing system has been widely adopted in the carsharing field due to its flexible services. However, as one of the main limitations of the one-way carsharing system, the imbalance between supply and demand needs to be solved. Predicting pick-up demand has been studied to achieve the goal, but using returned vehicles to reduce unnecessary relocation is also one of the important methods. Nowadays, trajectory data and other data are available for real-time prediction for return demand. Based on the return demand prediction, the relocation response can be more reasonable. Thus, the balance of demand and supply can be largely improved. The multisource data include trajectory data, user application log data, order data, station data, and user characteristic data. Based on these data, a return demand prediction model was used to predict whether the user will return the vehicle in 15 min in real time, and a destination station prediction model was applied to forecast which station the user will park at. Finally, a case study using ten stations’ one-week field data was conducted to test the benefit of the dynamic return demand prediction. The results showed that the return demand prediction improves the efficiency of the relocations by mitigating the condition that the station parking space is full or empty. The potential application of this study would effectively reduce unnecessary relocation and further formulate an active operation optimization strategy to reduce the system’s operational cost and improve the service quality of the system.

Analysis and Optimization of a Passive Micromixer With Curved-Shaped Baffles for Efficient Mixing With Low Pressure Loss in Continuous Flow

2010 ◽  
Author(s):  
Cesar A. Cortes-Quiroz ◽  
Alireza Azarbadegan ◽  
Emadaldin Moeendarbary ◽  
Mehrdad Zangeneh
Keyword(s):  
Pressure Loss ◽  
Cost Effective ◽  
Optimization Method ◽  
Secondary Flows ◽  
Design Parameters ◽  
Mixing Efficiency ◽  
Outlet Section ◽  
Optimization Strategy ◽  
Mixing Index ◽  
Trade Offs

Numerical simulations and an optimization method are used to study the design of a planar T-micromixer with curved-shaped baffles in the mixing channel. The mixing efficiency and the pressure loss in the mixing channel have been evaluated for Reynolds number (Re) in the mixing channel in the range 1 to 250. A Mixing index (Mi) has been defined to quantify the mixing efficiency. Three geometric dimensions: radius of baffle, baffles pitch and height of the channel, are taken as design parameters, whereas the mixing index at the outlet section and the pressure loss in the mixing channel are the performance parameters used to optimize the micromixer geometry. To investigate the effect of design and operation parameters on the device performance, a systematic design and optimization methodology is applied, which combines Computational Fluid Dynamics (CFD) with an optimization strategy that integrates Design of Experiments (DOE), Surrogate modeling (SM) and Multi-Objective Genetic Algorithm (MOGA) techniques. The Pareto front of designs with the optimum trade-offs of mixing index and pressure loss is obtained for different values of Re. The micromixer can enhance mixing using the mechanisms of diffusion (lower Re) and convection (higher Re) to achieve values over 90%, in particular for Re in the order of 100 that has been found the cost-effective level for volume flow. This study applies a systematic procedure for evaluation and optimization of a planar T-mixer with baffles in the channel that promote transversal 3-D flow as well as recirculation secondary flows that enhance mixing.

The Datum Flow Chain: A Systematic Approach to Assembly Design and Modeling

1998 ◽  
Author(s):  
R. Mantripragada ◽  
D. E. Whitney
Keyword(s):  
Design Process ◽  
Systematic Approach ◽  
Assembly Planning ◽  
Assembly Process ◽  
Top Down ◽  
Assembly Design ◽  
Key Characteristics ◽  
Assembly Sequences

Abstract In order to be able to lay out, analyze, outsource, assemble, and debug complex assemblies, we need ways to capture their fundamental structure in a top-down design process, including the designer’s strategy for kinematically constraining and locating the parts accurately with respect to each other. We describe a concept called the “Datum Flow Chain” to capture this logic. The DFC relates the datum logic explicitly to the product’s key characteristics, assembly sequences, and choice of mating features, and provides the information needed for tolerance analyses. Two types of assemblies are addressed: Type-1 where the assembly process puts parts together at their prefabricated mating features, and Type-2 where the assembly process can incorporate in-process adjustments to redistribute variation. Two types of assembly joints are defined: mates that pass dimensional constraint from part to part, and contacts that merely provide support. The scope of DFC in assembly planning is presented using several examples. Analysis tools to evaluate different DFCs and select the ones of interest are also presented.

scholarly journals Trajectory Planning Based on Screw Theory with Consideration of the Optimal Berth Position for a Space Robot

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Yong Wang ◽  
Ying Liao ◽  
Kejie Gong
Keyword(s):  
Trajectory Planning ◽  
Screw Theory ◽  
Optimization Method ◽  
Euler Method ◽  
Space Robot ◽  
Optimization Strategy ◽  
Generalized Jacobian ◽  
End Effector ◽  
Planning Strategy ◽  
Exponential Formula

Trajectory planning is a prerequisite for the tracking control of a free-floating space robot. There are usually multiple planning objectives, such as the pose of the end-effector and the base attitude. In efforts to achieve these goals, joint variables are often taken as exclusive operable parameters, while the berth position is neglected. This paper provides a novel trajectory planning strategy that considers the berth position by applying screw theory and an optimization method. First, kinematic equations at the position level are established on the basis of the product of exponential formula and the conservation of the linear momentum of the system. Then, generalized Jacobian matrices of the base and end-effector are derived separately. According to the differential relationship, an ordinary differential equation for the base attitude is established, and it is solved by the modified Euler method. With these sufficient and necessary preconditions, a parametric optimization strategy is proposed for two trajectory planning cases: zero attitude disturbance and attitude adjustment of the base. First, the berth position is transformed into the desired position of the end-effector, and its constraints are described. Joint variables are parameterized using a sinusoidal function combined with a five-order polynomial function. Then, objective functions are constructed. Finally, a genetic algorithm with a modified mutation operator is used to solve this optimization problem. The optimal berth position and optimized trajectory are obtained synchronously. The simulation of a planar dual-link space robot demonstrates that the proposed strategy is feasible, concise, and efficient.

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