Linkage Design Research Articles

Algorithmic Accountability for Record Linkage

This session will examine record linkage approaches through the lens of principles for algorithmic accountability: responsibility, explainability, accuracy, auditability, and fairness.[1] It is easy to hypothesize cases where linkage algorithms could have disparate impacts, such as linking names more or less easily depending on their cultural background. How can researchers use careful linkage design and sensitivity testing to identify and, where necessary, mediate these impacts? What does it look like for record linkage processes to be explainable and auditable—and how can researchers invite engagement from broader groups of stakeholders in considering linkage methods? We will present on our experiences identifying and addressing these challenges in the context of linking state and local public sector administrative data sources. These data sources, which generally include populations engaging with particular programs or systems, have especially variable data quality and are often marred by structural biases. Our approach to linking these datasets emphasizes integrating policy and data context, interrogating linkage decisions for iterative improvement, and collaborating with a wide range of stakeholders for equitable, accountable data use. We will demonstrate examples of how linkage decisions and results have varied across contexts. [1] Diakopoulos, N., Friedler, S., Arenas, M., Barocas, S., Hay, M., Howe, B., Jagadish, H.V., Unsworth, K., Sahuguet, A., Venkatasubramanian, S., Wilson, C., Yu, C., and Zevenbergen, B. (2016). Principles for Accountable Algorithms and a Social Impact Statement for Algorithms. Fairness, Accountability, and Transparency in Machine Learning. https://www.fatml.org/resources/principles-for-accountable-algorithms.

Trajectory Synthesis and Linkage Design of Single-Degree-of-Freedom Finger Rehabilitation Device

For injured and after-stroke patients who temporarily lose their hand’s grasping abilities, assisting them in regaining their index finger mobility is very important in the rehabilitation process. In this paper, a finger rehabilitation device based on one degree-of-freedom (DOF) linkage mechanism is designed, aiming to lead the index finger through the flexion–extension trajectory during grasping tasks. Two types of one-DOF mechanisms, a four-bar linkage and a Watt-I six-bar linkage, are synthesized for the task trajectory. Various algorithms such as PSO, GA, and GA–BFGS are adopted and compared for the synthesis of these two types of mechanisms, among which the Watt-I six-bar linkage obtained with GA–BFGS shows the optimal performance in accuracy. Clinical biomechanical data are utilized to perform static analyses of the mechanisms, and the feasibility of the Watt-I six-bar linkage models is tested, compared, and demonstrated. Finally, the prototype of the six-bar linkage as well as a wearable exoskeleton finger rehabilitation device are designed to show how they are applied in the finger rehabilitation scenario.

Bi-level game theoretic approach for robust design: A case study of path-generating four-bar

This study addresses the bi-level multi-objective optimization problems (MOP) that raise in robust design and optimization of engineering systems through establishing a state-of-the-art game theoretic scenario. A novel leader-follower decentralized decision-making scenario is proposed, leveraging the synergy of game theory, Robust Design Optimization (RDO), Monte Carlo Simulation (MCS), and Artificial Intelligence (AI). The proposed algorithm can be employed for optimum robust Pareto design of a wide range of dynamical systems. In order to achieve a robust design, both the mean and variance of each objective function are considered as players in a multi-agent game setting. In this approach, both Stackelberg and cooperative games are utilized to model the behaviors of the players. Genetic Programming (GP) meta-models are employed to capture the Stackelberg protocol between two levels specifically for constructing the follower's rational reaction set (RRS). Additionally, the Nash bargaining function is -utilize to model the cooperative behaviors among players in each level. The proposed approach is applied and demonstrated through a case study involving multi-objective robust design of planar four-bar linkages. In this manner, four objective functions are assigned to four players within the system. Each player is responsible for optimizing a specific objective criterion, namely the mean of tracking error (TE), variance of tracking error, mean of transmission angle and variance of transmission angle (TA) of the linkage. As a result, the four-objective optimization problem of mechanism is transformed into a single-objective robust synthesis problem. The comparisons of the results show a significant enhancement in the robust behavior of the linkage, while ensuring that deterministic criteria such as quality of motion and precision are preserved.

3D auxetic linkage based on Kirigami

The structural design of 3D auxetic linkages is a burgeoning field in digital manufacturing. This article presents a novel algorithm for designing 3D auxetic linkage structures based on Kirigami principles to address existing limitations. The 3D input model is initially mapped to a 2D space using conformal mapping based on the BFF method. This is followed by 2D re-meshing using an equilateral triangle mesh. Subsequently, a 3D topological mesh of the auxetic linkage is calculated through inverse mapping based on directed area. We then introduce new basic rotating and non-rotating units, employing them as the initial structure of the 3D auxetic linkage in accordance with Kirigami techniques. Lastly, a deformation energy function is defined to optimize the shape of the rotating units. The vertex coordinates of the non-rotating units are updated according to the optimized positions of the rotating units, thereby generating an optimal 3D auxetic linkage structure. Experimental results validate the effectiveness and accuracy of our algorithm. Quantitative analyses of structural porosity and optimization accuracy, as well as comparisons with related works, indicate that our algorithm yields structures with smaller shape errors.

A reconfigurable multi-terrain adaptive casualty transport aid base on Watt II six-bar linkage for industrial environment.

Introduction: This paper presents the Reconfigurable Multi-Terrain Adaptive Casualty Transport Aid (RMTACTA), an innovative solution addressing the critical need for rapid and safe pre-hospital casualty transport in industrial environments. The RMTACTA, leveraging the Watt II six-bar linkage, offers enhanced adaptability through six modes of motion, overcoming the limitations of traditional stretchers and stretcher vehicles by facilitating navigation across narrow and challenging terrains. Methods: The RMTACTA's design incorporates two branching four-bar mechanisms to form a compact, reconfigurable Watt II six-bar linkage mechanism. This setup is controlled via a single remote rope, allowing for easy transition between its multiple operational modes, including stretcher, stretcher vehicle, folding, gangway-passing, obstacle-crossing, and upright modes. The mechanical design and kinematics of this innovative linkage are detailed, alongside an analysis of the optimal design and mechanical evaluation of rope control. Results: A prototype of the RMTACTA was developed, embodying the proposed mechanical and kinematic solutions. Preliminary tests were conducted to verify the prototype's feasibility and operability across different terrains, demonstrating its capability to safely and efficiently transport casualties. Discussion: The development of the proposed Reconfigurable Multi-Terrain Adaptive Casualty Transport Aid (RMTACTA) introduces a novel perspective on the design of emergency medical transport robots and the enhancement of casualty evacuation strategies. Its innovative application of the Watt II six-bar linkage mechanism not only showcases the RMTACTA's versatility across varied terrains but also illuminates its potential utility in critical scenarios such as earthquake relief, maritime rescue, and battlefield medical support.

Design of a Novel Linkage for Electronic Parking Brake Transmission Systems

Abstract This paper presents a novel mechanical transmission for pulling-cable electronic parking brakes (EPBs). The system is interposed between the brake electric actuator and the brake pads, and it exploits a 2DOF planar linkage to provide the requested brake force and ensure the correct vehicle standstill. This paper describes the working principles and main component of the adopted architecture, and compares it with the EPB state of the art. Thereafter, the paper focuses on the system requirements and consequent functional design. A first prototype of the presented mechanical transmission is then presented to discuss the role of a mechanical engagement within the system to ensure its proper behavior. In conclusion, the EPB drive motor assessment is discussed on the basis of a simplified drive chain dynamic model.

Coupled occupant-suspension-seat system analysis and vehicle-specific design optimization

A suspension seat is generally designed to achieve attenuation of low frequency whole-body vibration for a broad range of vehicles. Owing to the strong dependence of its vibration isolation performance on the nature of vibration excitation, an optimal performance could be realized via optimal tuning of suspension for specific classes of vehicles. In this study, a coupled occupant suspension seat model is developed and analyzed to identify optimal design parameters for different classes of vehicles. The multibody dynamic model of the air suspension seat is formulated considering kineto-dynamics of the suspension system and the elastic motion-limiters. The component models, namely, air spring with auxiliary air volume, hydraulic damper, and cushion, are identified from the laboratory-measured static and dynamic characteristics. A two-degree-of-freedom occupant model, is integrated to the suspension seat model to account for contribution due to occupant biodynamics. Model validity is examined using the laboratory-measured responses with a rigid load and a human occupant of similar body weight, and analyzed for different body weights and excitation spectra. The results suggest strong dependency of the suspension resonance frequency on nonlinear behavior of the air spring and the seated body mass. The model is subsequently employed to identify optimal coordinates of the air spring to achieve nearly constant natural frequency for a broad range of body masses. Furthermore, the model is used to identify optimal linkage and suspension design parameters with an objective to minimize the SEAT (Seat Effective Amplitude Transmissibility) for different spectral classes of earth moving machines defined in the ISO-7096 standard, while limiting the suspension travel. It is shown that the optimal coordinates of air spring could yield nearly constant natural frequency for different body weights, while damper could help limit the suspension travel, in addition to notable reductions in SEAT, ranging from 9% to 31% for different spectral classes of vehicles.

Optimal Leg Linkage Design for Horizontal Propel of a Walking Robot Using Non-Dominated Sorting Genetic Algorithm

Optimal Leg Linkage Design for Horizontal Propel of a Walking Robot Using Non-Dominated Sorting Genetic Algorithm

Challenges in Remote Study Design: An Infrastructure Review of a Linkage Study

Planning and designing a study that links content analysis and panel data is a complex endeavor and managing a collaborative research project across multiple organizations involves many hurdles and challenges. Both, the complexity of a linkage design and the challenging nature of a collaborative research project are enhanced by the COVID-19 pandemic, demanding creative solutions for many issues and a lot of planning by the researchers involved. Especially the challenges involved in gathering, storing, analyzing, and accessing data are amplified by the lack of face-to-face contact and standardized technical infrastructure for digital collaborative research projects. This article aims at giving an overview of the technical infrastructure involved in the content analysis part of a large-scale linkage study, providing researchers with a blueprint of the many moving parts involved in the study’s implementation. This overview will be discussed with a reflective eye toward the challenges encountered and solutions found in the process, the added layer of complexity of a global pandemic, and potential learnings for future projects like this.

An Extensive Analysis of the Engineering Design of Underground Sewage Plants in China

In recent years, underground sewage treatment plants that can remarkably reduce land occupation with less environmental pollution are gradually entering the popular consciousness and are now being used widely. However, problems associated with the traditional treatment plants, such as high construction and operation cost, severe health and safety risks, and monotonous landscape design have limited their value and restricted their application and promotion. Through the literature and field investigations, the value of underground sewage treatment plants (STPs) was analyzed, their engineering and landscape design were studied, and their development direction was explored in order to supply a theoretical basis for further application and development of underground STPs. The analysis showed that as a new model of environmentally friendly sewage treatment and resource conservation, underground STPs have the apparent advantages of lower cost of land use for construction and pipeline as well as an outstanding value for the urban landscape and ecological environment. These factors can offset its relatively high construction and operating costs to a certain extent, especially when compared with above-ground STPs. The engineering design study results showed that significant differences existed between underground STPs and traditional above-ground STPs, and that the main contents of the engineering design of underground STPs consist of treatment scale and degree, influent and effluent qualities, site selection, design model, underground arrangement and structure, main treatment process, monomer structure, ventilation and deodorization, daylighting and artificial lightings, fire safety, operation and maintenance, and the linkage design between the above-ground landscape and the underground STP.

Research Progress in Donor-Acceptor Type Covalent Organic Frameworks.

Covalent organic frameworks (COFs) are new organic porous materials constructed by covalent bonds, with the advantages of pre-designable topology, adjustable pore size, and abundant active sites. Many research studies have shown that COFs exhibit great potential in gas adsorption, molecular separation, catalysis, drug delivery, energy storage, etc. However, the electrons and holes of intrinsic COF are prone to compounding in transport, and the carrier lifetime is short. The donor-acceptor (D-A) type COFs, which are synthesized by introducing D and A units into the COFs backbone, combine separated electron and hole migration pathway, tunable band gap and optoelectronic properties of D-A type polymers with the unique advantages of COFs and have made great progress in related research in recent years. Here, the synthetic strategies of D-A type COFs are first outlined, including the rational design of linkages and D-A units as well as functionalization approaches. Then the applications of D-A type COFs in catalytic reactions, photothermal therapy, and electronic materials are systematically summarized. In the final section, the current challenges, and new directions for the development of D-A type COFs are presented.

Linkage Analysis Revised – Linking Digital Traces and Survey Data

ABSTRACT Linkage analysis, i.e. linking media exposure, content, and surveys, has been a powerful tool to assess media effects. However, the development of online communication and the advent of social media brings about many challenges for traditional linkage designs. In this paper, we explain the three steps of linkage designs for online communication effects and the usage of computational approaches to capture communication exposure and content. We then review recent designs and studies that use different forms of digital trace data to link digital communication exposure, content, and surveys: Tracking data, data donations, and screenshots/screen recordings. We describe (practical) challenges and opportunities when linking digital communication traces with self-reports and show how these data could be analyzed to establish different media effects.

Design of the five-bar linkage with singularity-free workspace

AbstractThis paper shows the kinematic analysis and the synthesis of the five-bar linkage with symmetrical structure and singularity-free dexterous workspace. The type synthesis of the five-bar linkage shows that the number of symmetrical structures of five-bar linkage is limited to eight structures. This study deals with the forward and inverse kinematic analysis and synthesis of the five-bar structure 5-RRRRR. The synthesis equations allow the analytical computation of the link lengths of a symmetrical five-bar linkage using only revolute joints to avoid the singularities in an imposed dexterous workspace. A numerical example of the symmetrical five-bar linkage is analyzed and synthetized theoretically and characterized by computing the performance indices. The tests on an experimental model of the five-bar linkage 5-RRRRR confirm the singularity-free dexterous workspace.

Kinematic Design of Adaptive Control Adjustable Stroke Piston Pump for Automated Lubrication System

Lubrication is done either manually or using automatic systems, the purpose of the automatic lubrication system is to provide certain amount of lubricant at given time to the machines the proposed work is based on auto control variable displacement pump and referencing to literature survey it is a novel work involves, an innovative kinematic link base stroke changing mechanism. The stoke variation mechanism serves to alter the stroke of the piston pump in a controlled manner to control the flow rate of the pump precisely. The present work pertains to the design theoretically and kinematic synthesis of the components of the kinematic linkage. The theoretical design of the kinematic linkage is done using graphical method by overlay method, and the analysis of the kinematic linkage is done using adam’s software. The linkage motion for various angle of crank and corresponding output link are derived from this kinematic synthesis. The kinematic analysis of the linkage is done in using adam’s software and the motion study of the link is done to determine the parameters velocity of link and acceleration of link used in the mechanism.

Drug-Grafted DNA for Cancer Therapy.

With the development of solid-phase synthesis and DNA nanotechnology, DNA-based drug delivery systems have seen large advancements over the past decades. By combining various drugs (small-molecular drugs, oligonucleotides, peptides, and proteins) with DNA technology, drug-grafted DNA has demonstrated great potential as a promising platform in recent years, in which complementary properties of both components have been discovered; for instance, the synthesis of amphiphilic drug-grafted DNA has enabled the production of DNA nanomedicines for gene therapy and chemotherapy. Through the design of linkages between drug and DNA parts, stimuli-responsiveness can be instilled, which has boosted the application of drug-grafted DNA in various biomedical applications such as cancer therapy. This review discusses the progress of various drug-grafted DNA therapeutic agents, exploring the synthetic techniques and anticancer applications afforded through the combination of drug and nucleic acids.

An alternating optimization approach integrating linkage design with motion planning for jumping robot

Jumping, as widely observed amongst agile terrestrial creatures, is regarded as an indispensable ability for legged robots with high-performance in dealing with complex environments. This study presents a novel leg design methodology for jumping robot using the alternating iteration approach that optimizes the leg linkage and the specified jumping motion to completely leverage the capability of the actuator. First, a coaxial parallel five-link mechanism (CPFM) classification method was proposed to extract feasible candidates of leg configuration to alleviate the intensely searching complexity due to multi-link singularity. An alternating optimization paradigm was developed by elaborately combining the motion planning (MP) and the linkage design (LD) to generate a favorable leg with a CPFM morphology. The MP task was constructed to maximize the jumping distance of the robot while the LD task was proposed to minimize the peak demand of the actuators. Finally, a sagittal jumping robot prototype was developed based on the optimal results from the proposed paradigm. We obtained a horizontal jumping performance of 1.8 times the maximum leg length, which is comparable to the natural performance of a human.

Kinegami: Algorithmic Design of Compliant Kinematic Chains From Tubular Origami

Origami processes can generate both rigid and compliant structures from the same homogeneous sheet material. In this article, we advance the origami robotics literature by showing that it is possible to construct an arbitrary rigid kinematic chain with prescribed joint compliance from a single tubular sheet. Our “Kinegami” algorithm converts a Denavit–Hartenberg specification into a single-sheet crease pattern for an equivalent serial robot mechanism by composing origami modules from a catalogue. The algorithm arises from the key observation that tubular origami linkage design reduces to a Dubins path planning problem. The automatically generated structural connections and movable joints that realize the specified design can also be endowed with independent user-specified compliance. We apply the Kinegami algorithm to a number of common robot mechanisms and hand-fold their algorithmically generated single-sheet crease patterns into functioning kinematic chains. We believe this is the first completely automated end-to-end system for converting an abstract manipulator specification into a physically realizable origami design that requires no additional human input.

Design Tradeoff Between Saliency Ratio and PM Flux Linkage in Variable Flux Memory Machines

To achieve flexible flux regulation, variable flux memory machines (VFMMs) are normally characterized by a high permanent magnet (PM) flux linkage design, which generally reduces the saliency ratio of the machine. In order to further reveal the internal performance tradeoffs, this paper investigates the relationship between the saliency ratio and PM flux linkages of VFMMs by combining the equivalent magnetic circuit models and the finite element (FE) method. Three hybrid-magnetic-circuit (HMC) VFMMs having different PM grades and saliency ratios are chosen as the case studies to analyze and reveal the influence of flux linkages and saliency ratios on the major electromagnetic characteristics. First, the no-load and dq-axes equivalent magnetic circuit models of the investigated machines are established successively to obtain the PM flux linkages and dq-axes inductances of the machines. Then, the relationships between the electromagnetic torque and the key design parameters are obtained based on the space vector model. Next, the maximum torque per ampere (MTPA) trajectory is portrayed to determine the flux-weakening characteristics of the VFMMs. Afterwards, the electromagnetic characteristics of the three machines are compared and analyzed to confirm the previous theoretical analyses. Finally, an HMC-VFMM prototype is fabricated and tested to verify the effectiveness of the analysis.

Linkage Design in Two-Dimensional Covalent Organic Frameworks for High Iodine Uptake.

Radioactive iodine waste in the nuclear field is harmful to the environment and human health. Covalent organic frameworks (COFs) are a novel kind of porous organic material with a well-fine and unformal structure, which is an excellent candidate as a solid adsorbent for iodine adsorption. Herein, a linkage design is proposed for effective iodine adsorption. Imine-linkage COF (I-COF) and hydrazone-linked COF (H-COF) are constructed under solvothermal conditions. The Brunauer-Emmett-Teller surface area of H-COF is as high as 1747 m2 g-1 . Furthermore, the H-COF shows high porosity, stability, and rich atoms in the linkage. As a result, the work outperforms most of the previous reports in iodine capture with a high capture value at 5.72gg-1 .

Optimal Design and Dynamic Analysis of a Spring-Actuated Cam-Linkage Mechanism in a Vacuum Circuit Breaker

This study attempted to establish an optimal design and perform dynamic analysis for a spring-actuated cam-linkage composite mechanism in a rated 12 kV, 25 kA vacuum circuit breaker (VCB). The optimal design of the VCB mechanism involves two steps: the first step involves the optimal design of the stiffness of closing springs and the cam profile, based on three-order polynomial motion curve of the follower; the second step involves the optimal design of a four-bar linkage. To minimize the surplus work in the VCB operating mechanism, the overall difference between the general output force and general resistant force of the VCB operating mechanism during the closing operation was adopted as the objective function to be minimized. Furthermore, the differential evolution algorithm with the golden ratio (DE-gr), an efficient and accuracy metaheuristic algorithm, was employed as the optimization method. The dynamic analysis of the optimal operating mechanism was conducted using a MATLAB-coded program and verified by the multibody dynamic software MSC-ADAMS. The dynamic analysis revealed that the optimal design of the VCB mechanism can considerably decrease the average closing velocity of the movable contact and the Hertz stress between the contact surface of the cam and the roller follower.