Synthesis of Watt-type Timed Curve Generators and Selection from Continuous Cognate Spaces

2021 ◽  
pp. 1-11
Author(s):  
Aravind Baskar ◽  
Mark Plecnik
Keyword(s):  
Recent Work ◽  
Polynomial Systems ◽  
Number Of Solutions ◽  
End Effector ◽  
Continuous Space ◽  
Trade Offs ◽  
Synthesis Of Mechanisms ◽  
Free Parameters ◽  
Selection Of

Abstract Following recent work on Stephenson-type mechanisms, the synthesis equations of Watt six-bar mechanisms that act as timed curve generators are formulated and systematically solved. Four variations of the problem arise by assigning the actuator and end effector onto different links. The approach produces exact synthesis of mechanisms up to eight precision points. Polynomial systems are formulated and their maximum number of solutions is estimated using the algorithm of random monodromy loops. Certain variations of Watt timed curve generators possess free parameters that do not affect the output motion, indicating a continuous space of cognate mechanisms. Packaging compactness, clearance, and dimensional sensitivity are characterized across the cognate space to illustrate trade-offs and aid in selection of a final mechanism.

Addressing pose estimation issues for machine vision based UAV autonomous serial refuelling

2007 ◽  
Vol 111 (1120) ◽  
pp. 389-396 ◽  
Author(s):  
G. Campa ◽  
M. R. Napolitano ◽  
M. Perhinschi ◽  
M. L. Fravolini ◽  
L. Pollini ◽  
...  
Keyword(s):  
Machine Vision ◽  
Pose Estimation ◽  
Estimation Algorithm ◽  
Computational Effort ◽  
Unmanned Aircraft ◽  
Light Sources ◽  
Estimation Algorithms ◽  
Trade Offs ◽  
Labeling Algorithms ◽  
Selection Of

Abstract This paper describes the results of an effort on the analysis of the performance of specific ‘pose estimation’ algorithms within a Machine Vision-based approach for the problem of aerial refuelling for unmanned aerial vehicles. The approach assumes the availability of a camera on the unmanned aircraft for acquiring images of the refuelling tanker; also, it assumes that a number of active or passive light sources – the ‘markers’ – are installed at specific known locations on the tanker. A sequence of machine vision algorithms on the on-board computer of the unmanned aircraft is tasked with the processing of the images of the tanker. Specifically, detection and labeling algorithms are used to detect and identify the markers and a ‘pose estimation’ algorithm is used to estimate the relative position and orientation between the two aircraft. Detailed closed-loop simulation studies have been performed to compare the performance of two ‘pose estimation’ algorithms within a simulation environment that was specifically developed for the study of aerial refuelling problems. Special emphasis is placed on the analysis of the required computational effort as well as on the accuracy and the error propagation characteristics of the two methods. The general trade offs involved in the selection of the pose estimation algorithm are discussed. Finally, simulation results are presented and analysed.

A Spectral Optimization Algorithm for Multi-Objective Prototype Selection

1995 ◽  
Author(s):  
Andy Dong ◽  
Alice M. Agogino
Keyword(s):  
Optimization Algorithm ◽  
Parametric Design ◽  
Selection Process ◽  
Objective Evaluation ◽  
Design Synthesis ◽  
Multi Objective ◽  
Trade Offs ◽  
Spectral Optimization ◽  
The Right ◽  
Selection Of

Abstract In design synthesis, engineering prototypes make an ideal representation medium for preliminary designs. Unlike parametric design wherein a pre-specified design is parametrically varied, design synthesis demands artistic creativity and engineering experience to transform the previously known components, relationships and designs into a new form. The process compels the designer to ascertain which prototypes will, in some sense, best satisfy the design task. The challenge in this assignment lies in selecting the “right” design prototype. This selection process typically entails an objective evaluation of different designs that perform the same functions or have similar intended behavior and comparing trade-offs between alternate designs. This paper introduces a multi-objective spectral optimization algorithm for the selection of design prototypes based upon their functional representations. The optimization algorithm returns an index of rank, scoring the functional similarity of the proposed design to the goal design. Two illustrative examples apply the algorithm to the selection of a heat fin and beam.

scholarly journals ON SOLUTIONS TO SOME POLYNOMIAL CONGRUENCES IN SMALL BOXES

2013 ◽  
Vol 89 (2) ◽  
pp. 300-307
Author(s):  
IGOR E. SHPARLINSKI
Keyword(s):  
Exponential Sums ◽  
Polynomial Systems ◽  
Side Length ◽  
Character Sum ◽  
Number Of Solutions ◽  
Polynomial Congruences

AbstractWe use bounds of mixed character sum to study the distribution of solutions to certain polynomial systems of congruences modulo a prime $p$. In particular, we obtain nontrivial results about the number of solutions in boxes with the side length below ${p}^{1/ 2} $, which seems to be the limit of more general methods based on the bounds of exponential sums along varieties.

Multi-objective optimization for safety and reliability trade-off: Optimization and results processing

2018 ◽  
Vol 232 (6) ◽  
pp. 661-676
Author(s):  
Cristina Johansson ◽  
Johan Ölvander ◽  
Micael Derelöv
Keyword(s):  
Decision Making ◽  
Solid Base ◽  
Multi Objective Optimization ◽  
Specific System ◽  
Multi Objective ◽  
Trade Offs ◽  
Design Alternatives ◽  
Safety And Reliability ◽  
Potential Issue ◽  
Selection Of

In early design phases, it is vital to be able to screen the design space for a set of promising design alternatives for further study. This article presents a method able to balance several objectives of different mathematical natures, with high impact on the design choices. The method (MOSART) handles multi-objective optimization for safety and reliability trade-offs. The article focuses on optimization problem approach and processing of results as a base for decision-making. The output of the optimization step is the selection of specific system elements obtaining the best balance between the targets. However, what is a good base for decision can easily transform into too much information and overloading of the decision-maker. To solve this potential issue, from a set of Pareto optimal solutions, a smaller sub-set of selected solutions are visualized and filtered out using preference levels of the objectives, yielding a solid base for decision-making and valuable information on potential solutions. Trends were observed regarding each system element and discussed while processing the results of the analysis, supporting the decision of one final best solution.

scholarly journals Are trade-offs between flexibility and efficiency in systematic conservation planning avoidable ?

2019 ◽  
Author(s):  
Sabrine Drira ◽  
Frida Ben Rais Lasram ◽  
Tarek Hattab ◽  
Yunne Jai Shin ◽  
Amel Ben Rejeb Jenhani ◽  
...  
Keyword(s):  
Conservation Planning ◽  
Large Body ◽  
Efficient Solutions ◽  
Reserve Selection ◽  
Systematic Conservation Planning ◽  
Distribution Models ◽  
Precise Control ◽  
Trade Offs ◽  
Selection Framework ◽  
Selection Of

AbstractSpecies distribution models (SDMs) have been proposed as a way to provide robust inference about species-specific sites suitabilities, and have been increasingly used in systematic conservation planning (SCP) applications. However, despite the fact that the use of SDMs in SCP may raise some potential issues, conservation studies have overlooked to assess the implications of SDMs uncertainties. The integration of these uncertainties in conservation solutions requires the development of a reserve-selection approach based on a suitable optimization algorithm. A large body of research has shown that exact optimization algorithms give very precise control over the gap to optimality of conservation solutions. However, their major shortcoming is that they generate a single binary and indivisible solution. Therefore, they provide no flexibility in the implementation of conservation solutions by stakeholders. On the other hand, heuristic decision-support systems provide large amounts of sub-optimal solutions, and therefore more flexibility. This flexibility arises from the availability of many alternative and sub-optimal conservation solutions. The two principles of efficiency and flexibility are implicitly linked in conservation applications, with the most mathematically efficient solutions being inflexible and the flexible solutions provided by heuristics suffering sub-optimality. In order to avoid the trade-offs between flexibility and efficiency in systematic conservation planning, we propose in this paper a new reserve-selection framework based on mathematical programming optimization combined with a post-selection of SDM outputs. This approach leads to a reserve-selection framework that might provide flexibility while simultaneously addressing efficiency and representativeness of conservation solutions and the adequacy of conservation targets. To exemplify the approach we a nalyzed an experimental design crossing pre- and post-selection of SDM outputs versus heuristics and exact mathematical optimizations. We used the Mediterranean Sea as a biogeographical template for our analyses, integrating the outputs of 8 SDM techniques for 438 fishes species.

scholarly journals ANALYSIS OF THE CONSUMERS PREFERENCES OF LIPSTICK PRODUCT AND ITS RELATIONSHIP WITH THE SEGMENTATION OF THE LIPSTICK PRODUCTS

2018 ◽  
Vol 1 (02) ◽  
pp. 7
Author(s):  
Mohammad Wartaka
Keyword(s):  
Conjoint Analysis ◽  
Skin Color ◽  
New Product ◽  
Quality Attributes ◽  
Global Brands ◽  
Importance Weight ◽  
Income Sources ◽  
Trade Offs ◽  
The City ◽  
Selection Of

The need for lipstick continues to increase along with the emergence of a new lipstick products both domestic and global brands to follow the needs of its consumers, the new product has a variety of functions other than just as a lip color, but also as a moisturizer / lip protection even as treatment. Adult lipstick is packed with advertisements and packaging are very interesting addition to the color choice of more and more. In determining the selection of lipstick products consumers often consider the combination of the main attributes and other factors that are trade-offs. This study aims to determine the attributes and combination of attributes among the most preferred by consumers for a segment of the age and the amount of income. Sources of data in this study were obtained from 138 respondents in the city of Bogor and its surroundings, conjoint analysis is used to determine the usefulness of each attribute and their relative weights as a tool to predict the preferences of a particular segment or as a whole. The results showed the order of importance weight according to the respondents is that the quality attributes (34.95%), the type of color (33.21%) and benefits (31.84%), while the combination of the most preferred products are: lipstick durable / waterproof, according to skin color, and functioning for moisturizing / protective lip. In the description also delivered conjoin analysis results for each age and income segments.

FLEXIBILITY VS. SPECIALISATION IN RO-RO SHIPPING IN THE SOUTH BALTIC SEA

Transport ◽  
2012 ◽  
Vol 27 (3) ◽  
pp. 250-262 ◽  
Author(s):  
Johan Woxenius
Keyword(s):  
Baltic Sea ◽  
Transport System ◽  
Open Systems ◽  
The South ◽  
Trade Off ◽  
Short Sea Shipping ◽  
Trade Offs ◽  
Empirical Context ◽  
Selection Of

The trade-off between flexibility and specialisation implies delicate tasks for transport system designers and marketing managers. The outcome of their efforts ranges from highly specialised solutions for a restricted number of users and types of cargoes to very open systems for common use adapted to accommodate a wide variety of transport demands. The purpose of this article is to adapt theories on openness and trade-offs, characterise a selection of flexible and specialised European short sea shipping concepts and analyse how substantial changes in the future character of the competition with road and rail can affect the development of ro-ro shipping in the South Baltic Sea. A matrix with commercial openness and technological openness on the axes is used for categorising sub-segments in the empirical context of the South Baltic Sea. Foreseeable changes in key cost and competition parameters until 2020 are taken into account in discussing potential scenarios. A plausible outcome for the ferry/ro-ro shipping segment is that a branch with slow services for unaccompanied freight will be diverted from the current homogenous market offerings. During the study, the Swedish Orient Line launched a service with these characteristics, which is analysed in a case study.

Kinematic Synthesis of Spatial R-R Dyads for Path Following Revisited Using the Rotation Matrix Approach

1999 ◽  
Author(s):  
Venkat Krovi ◽  
G. K. Ananthasuresh ◽  
Vijay Kumar
Keyword(s):  
Linear System ◽  
Path Following ◽  
Rotation Matrix ◽  
Dimensional Synthesis ◽  
Kinematic Synthesis ◽  
End Effector ◽  
Serial Chain ◽  
Systematic Development ◽  
Matrix Vector ◽  
Selection Of

Abstract We revisit the dimensional synthesis of a spatial two-link, two revolute-jointed serial chain for path following applications, focussing on the systematic development of the design equations and their analytic solution for the three precision point synthesis problem. The kinematic design equations are obtained from the equations of loop-closure for end-effector position in rotation-matrix/vector form at the three precision points. These design equations form a rank-deficient linear system in the link-vector components. The nullspace of the rank deficient linear system is then deduced analytically and interpreted geometrically. Tools from linear algebra are applied to systematically create the auxiliary conditions required for synthesis and to verify consistency. An analytic procedure for obtaining the link-vector components is then developed after a suitable selection of free choices. Optimization over the free choices is possible to permit the matching of additional criteria and explored further. Examples of the design of optimal two-link coupled spatial R-R dyads are presented where the end-effector interpolates three positions exactly and closely approximates an entire desired path.

scholarly journals Greedy Algorithm for Minimizing the Cost of Routing Power on a Digital Microgrid

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3076 ◽  
Author(s):  
Zhengqi Jiang ◽  
Vinit Sahasrabudhe ◽  
Ahmed Mohamed ◽  
Haim Grebel ◽  
Roberto Rojas-Cessa
Keyword(s):  
Optimal Solution ◽  
High Complexity ◽  
Distributed Energy ◽  
Optimal Method ◽  
Cost Rate ◽  
Trade Offs ◽  
Lower Complexity ◽  
Cost Paths ◽  
The Cost ◽  
Selection Of

In this paper, we propose the greedy smallest-cost-rate path first (GRASP) algorithm to route power from sources to loads in a digital microgrid (DMG). Routing of power from distributed energy resources (DERs) to loads of a DMG comprises matching loads to DERs and the selection of the smallest-cost-rate path from a load to its supplying DERs. In such a microgrid, one DER may supply power to one or many loads, and one or many DERs may supply the power requested by a load. Because the optimal method is NP-hard, GRASP addresses this high complexity by using heuristics to match sources and loads and to select the smallest-cost-rate paths in the DMG. We compare the cost achieved by GRASP and an optimal method based on integer linear programming on different IEEE test feeders and other test networks. The comparison shows the trade-offs between lowering complexity and achieving optimal-cost paths. The results show that the cost incurred by GRASP approaches that of the optimal solution by small margins. In the adopted networks, GRASP trades its lower complexity for up to 18% higher costs than those achieved by the optimal solution.

Ball Drive Configurations and Kinematics for Holonomic Ground Mobility

2017 ◽  
Author(s):  
Biruk A. Gebre ◽  
Kishore Pochiraju
Keyword(s):  
Design Space ◽  
Kinematic Model ◽  
Design Parameters ◽  
Actuation Force ◽  
Confined Spaces ◽  
Naming Convention ◽  
Trade Offs ◽  
Vehicle Velocity ◽  
And Performance ◽  
Selection Of

Holonomic motion is desired for mobile ground robots and vehicles as it provides omnidirectional maneuvering capabilities, which can simplify the task of navigating around obstacles in confined spaces and unstructured environments. Mobility platforms that utilize spherical wheels are gaining popularity and interest due to the agile maneuvering and ground traversal capabilities they enable for mobility platforms. Ball-driven mobility platforms have a rich design space as various design parameters are available that can modify the physical and performance characteristics of the platforms. Various configurations for ball-driven mobility platforms are presented along with a generalized kinematic model that can be used for calculating motor velocities for a desired vehicle velocity. A naming convention is also presented in the paper for differentiating between configurations used for ball-driven mobility platforms. Metrics such as platform footprint, platform stability, and actuation force and efficiency are used to compare the configurations and to highlight some of the trade-offs associated with the selection of a configuration. Promising configurations are highlighted based on the metrics selected for the comparisons.

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