Assembly Instructions Research Articles

Self-Adaptive Run-Time Variable Floating-Point Precision for Iterative Algorithms: A Joint HW/SW Approach

Using standard Floating-Point (FP) formats for computation leads to significant hardware overhead since these formats are over-designed for error-resilient workloads such as iterative algorithms. Hence, hardware FP Unit (FPU) architectures need run-time variable precision capabilities. In this work, we propose a new method and an FPU architecture that enable designers to dynamically tune FP computations’ precision automatically at run-time called Variable Precision in Time (VPT), leading to significant power consumption, execution time, and energy savings. In spite of its circuit area overhead, the proposed approach simplifies the integration of variable precision in existing software workloads at any level of the software stack (OS, RTOS, or application-level): it only requires lightweight software support and solely relies on traditional assembly instructions, without the need for a specialized compiler or custom instructions. We apply the technique on the Jacobi and the Gauss–Seidel iterative methods taking full advantage of the suggested FPU. For each algorithm, two modified versions are proposed: a conservative version and a relaxed one. Both algorithms are analyzed and compared statistically to understand the effects of VPT on iterative applications. The implementations demonstrate up to 70.67% power consumption saving, up to 59.80% execution time saving, and up to 88.20% total energy saving w.r.t the reference double precision implementation, and with no accuracy loss.

ViTroVo: in vitro assembly search for in vivo adaptive operator guidance: An artificial intelligence framework for highly customised manufacturing.

Product customisation is a topic of growing interest in Smart Manufacturing. Allowing customers to design intended products brings additional challenges to the manufacturing task, such as the increase in flexibility of the assembly theatre, the compilation of assembly instructions for possibly unique products, and stress-related risks for human operators. This work introduces ViTroVo, an artificial intelligence framework capable of (1) autonomously building a graph of assembly steps via trial-and-error (in vitro Assembly Search) and (2) presenting relevant instructions to a human operator and, by autonomously detecting her progress and affective state, adapting accordingly (in vivo Adaptive Operator Guidance). The power of ViTroVo resides in its versatile way to manipulate a given product’s component Augmented Computer Aided Design (CAD+) models throughout the whole assembly task. We conducted an empirical evaluation involving participants instructed to assemble a previously unseen product. The encouraging results make us believe ViTroVo’s architecture could become the foundations of highly customised flexible manufacturing.

Comparison of design approaches for low-cost sampling mechanisms in open-source chemical instrumentation

Robotic positioning systems are used in a variety of chemical instruments, primarily for liquid handling purposes, such as autosamplers from vials or well plates. Here, two approaches to the design of open-source autosampler positioning systems for use with 96-well plates are described and compared. The first system, a 3-axis design similar to many low-cost 3D printers that are available on the market, is constructed using an aluminum frame and stepper motors. The other system relies upon a series of 3D printed parts to achieve movement with a series of linker arms based on Selective Compliance Assembly Robot Arm (SCARA) design principles. Full printer design files, assembly instructions, software, and user directions are included for both samplers. The positioning precision of the 3-axis system is better than the SCARA mechanism due to finer motor control, albeit with a slightly higher cost of materials. Based on the improved precision of this approach, the 3-axis autosampler system was used to demonstrate the generation of a segmented flow droplet stream from adjacent wells within a 96-well plate.

Novel 3D printable powered air purifying respirator for emergency use during PPE shortage of the COVID-19 pandemic: a study protocol and device safety analysis

ObjectivesTo design a low-cost 3D printable powered air-purifying respirator (PAPR) that meets National Institute for Occupational Safety and Health (NIOSH) standard for flow rate and Occupational Safety and Health Administration...

IDENTIFYING THE FACTORS AFFECTING THE REPLICABILITY OF OPEN SOURCE HARDWARE DESIGNS

AbstractOpen-source hardware (OSH) development is a new design paradigm from a commercial perspective. Openly sharing designs of technical products is a step towards democratising access to new technologies for the benefit of individuals and communities in society. At the core of the open-source hardware definition lies the freedom for anyone to replicate the hardware based on the design. Thus, enabling this freedom is a step towards developing a successful OSH. Previous research supposes that a bill of materials and assembly instructions are enough for this. In this study, we question this assumption and investigate what other factors may influence replicability of an OSH. Using data from a survey and interviews with OSH practitioners, we identify and describe these factors, which relate to the documentation, the design and the context of the person replicating the hardware. Using these insights, we present a diagram of the replication process along with questions the person replicating the hardware would ask to check whether an OSH is replicable. Finally, we synthesise this information into practical advice for OSH projects to increase the replicability of the designs they produce, and thus the likelihood of their project's success.

Toying With Engineering: Teaching Engineers to Be Entrepreneurial by Developing a Toy

Most engineering design projects focus primarily on the engineering fundamentals. Studying the business case or manufacturability of a design is often left for other courses, if at all. To address this gap, an existing mechanical engineering course project was modified by embedding the interdependent entrepreneurial dimensions. In the past, junior engineering students developed a reciprocating air engines over two semesters. The modified project extended the engineering fundamentals into an entrepreneurial venture. To accomplish this, students were asked to propose an air engine toy for middle schoolers. The proposed toy had to be assembled, provide a learning opportunity, and demonstrate utility. The students had to ensure the product appealed to those interested in the STEM fields. The students, working in groups, created renders of the final product, assembly instructions, and a guided worksheet for the kids to explore the underlying engineering concept. The groups produced a website with a video pitching their toy concepts. This case study exemplifies how any engineering endeavor can be modified to capture a more holistic simulation of the profession.

Self-contained and modular structured illumination microscope.

We present a modular implementation of structured illumination microscopy (SIM) that is fast, largely self-contained and that can be added onto existing fluorescence microscopes. Our strategy, which we call HIT-SIM, can theoretically deliver well over 50 super-resolved images per second and is readily compatible with existing acquisition software packages. We provide a full technical package consisting of schematics, a list of components and an alignment scheme that provides detailed specifications and assembly instructions. We illustrate the performance of the instrument by imaging optically large samples containing sequence-specifically stained DNA fragments.

GAS DISTRIBUTION SYSTEM FOR OPTIMIZATION OF THE TECHNOLOGICAL PROCESS OF COATING IN AN UNBALANCED MAGNETRON SPUTTERING INSTALLATION

The paper proposes a new design solution for regulating the distribution of the working gases in the vacuum chamber of the installation (UDP -850/4) for unbalanced magnetron sputtering, which will improve the mode and quality of application of multilayer nano-coatings. Constructive documentation for manufacturing a gas distribution system has been prepared, as well as instructions for assembly to the vacuum chamber.

A learning experience toward the understanding of abstraction-level interactions in parallel applications

In the curriculum of a Computer Engineering program, concepts like parallelism, concurrency, consistency, or atomicity are usually addressed in separate courses due to their thoroughness and extension. Isolating such concepts in courses helps students not only to focus on specific aspects, but also to experience the reality of working with modern computer systems, where those concepts are often detached in different abstraction levels. However, due to such an isolation, it exists a risk of inducing to the students an absence of interactions between these concepts, and, by extension, between the different abstraction levels of a system.This paper proposes a learning experience showcasing the interactions between abstraction levels addressed in laboratory sessions of different courses. The driving example is a parallel ray tracer. In the different courses, students implement and assemble components of this application from the algorithmic level of the tracer to the assembly instructions required to guarantee atomicity. Each lab focuses on a single abstraction level, but shows students the interactions with the rest of the levels. Technical results and student learning outcomes through the analysis of surveys validate the proposed experience and confirm the students learning improvement with a more integrated view of the system.

Information integration and instruction authoring of augmented assembly systems

Augmented assembly (AA) is being gradually incorporated into manual assembly owing to its abundant instruction forms, high efficiency of information transmission, and robust interactivity. However, a lack of a unified description model for assembly information and irregular instruction design forms leads to difficulties in instruction authoring and generation, inconveniences for data management, and low system portability. To address these issues, this paper presents an information-integration and instruction-authoring method for AA systems. First, design guidelines for the AA instructions are established with the aim of minimizing the user's cognitive load. After that, the designing of visual elements is performed based on the design guidelines, and the information model of the assembly information and instructions is built using Unified Modeling Language. Based on Extensible Markup Language files and Unity3D engine, a standard and rapid development process is presented for deploying the AA system to Hololens2 devices. The usability and replicability of the designed system are demonstrated, and a user study is carried out. The user's task performance is evaluated using completion time and errors as metrics. The NASA-task load index scale is used to estimate the user's workload, and the Likert scale reflects the user's subjective perception of the system and instructions. The results show that the proposed AA instructions can effectively improve the user's task performance; reduce their workload, especially the cognitive load; and improve their assembly experience.

Design and development of a nozzle-free electrospinning device for the high-throughput production of biomaterial nanofibers

This technical note provides a step-by-step guide for the design and construction of a temperature-controlled nozzle-free electrospinning device. The equipment uses a rotating mandrel partially immersed within a polymer solution to produce fibers in an upward motion by inducing the formation of multiple Taylor cones and subsequently multi-jetting out of an electrified open surface. Free-surface electrospinning can overcome limitations and drawbacks associated with single and multi-nozzle spinneret configurations, such as low yield, limited production capacity, nonuniform electric field distribution, and clogging. Most importantly, this lab-scaled high-throughput device can provide an alternative economical route for needleless electrospinning research, in contrast to the high costs associated with industrially available upscaling equipment. Among the device's technical specifications, a key feature is a cryo-collector mandrel, capable of collecting fibers in sub-zero temperatures, which can induce ultra-porous nanostructures, wider pores, and subsequent in-depth penetration of cells. A multi-channel gas chamber allows the conditioning of the atmosphere, temperature, and airflow, while the chamber's design averts user exposure to the high-voltage components. All the Computer-Aided Design (CAD) files and point-by-point assembly instructions, along with a list of the materials used, are provided.

A simple, open and extensible gating Control unit for cardiac and respiratory synchronisation control in small animal MRI and demonstration of its robust performance in steady-state maintained CINE-MRI

Prospective cardiac gating during MRI is hampered by electromagnetic induction from the rapidly switched imaging gradients into the ECG detection circuit. This is particularly challenging in small animal MRI, as higher heart rates combined with a smaller myocardial mass render routine ECG detection challenging. We have developed an open-hardware system that enables continuously running MRI scans to be performed in conjunction with cardio-respiratory gating such that the relaxation-weighted steady state magnetisation is maintained throughout the scan. This requires that the R-wave must be detected reliably even in the presence of rapidly switching gradients, and that data previously acquired that were corrupted by respiratory motion re-acquired. The accurately maintained steady-state magnetisation leads to an improvement in image quality and removes alterations in intensity that may otherwise occur throughout the cardiac cycle and impact upon automated image analysis. We describe the hardware required to enable this and demonstrate its application and robust performance using prospectively cardio-respiratory gated CINE imaging that is operated at a single, constant TR. Schematics, technical drawings, component listing and assembly instructions are made publicly available.

On the Full- and Half-Sheet Inserts of Andreas Vesalius’s De humani corporis fabrica (1543 and 1555)

On the Full- and Half-Sheet Inserts of Andreas Vesalius’s <i>De humani corporis fabrica</i> (1543 and 1555)

Automatic Generation of ROP Through Static Instructions Assignment and Dynamic Memory Analysis

W⊕X is a protection mechanism against control-flow hijacking attacks. Return-oriented programming (ROP) can perform a specific function by searching for appropriate assembly instruction fragments (gadgets) in a code segment and bypass the W⊕X. However, manual search for gadgets that match the conditions is inefficient, with high error and missing rates. In order to improve the efficiency of ROP generation, the authors propose an automatic generation method based on a fragmented layout called automatic generation of ROP. This method designs new intermediate instruction construction rules based on an automatic ROP generation framework Q, uses symbolic execution to analyze program memory states and construct data constraints for multi-modules ROP, and solves ROP data constraints to generate test cases of an ROP chain. Experiments show that this method can effectively improve the space efficiency of the ROP chain and lower the requirements of the ROP layout on memory conditions.

A Customizable Low-Cost System for Massively Parallel Zebrafish Behavioral Phenotyping.

High-throughput behavioral phenotyping is critical to genetic or chemical screening approaches. Zebrafish larvae are amenable to high-throughput behavioral screening because of their rapid development, small size, and conserved vertebrate brain architecture. Existing commercial behavioral phenotyping systems are expensive and not easily modified for new assays. Here, we describe a modular, highly adaptable, and low-cost system. Along with detailed assembly and operation instructions, we provide data acquisition software and a robust, parallel analysis pipeline. We validate our approach by analyzing stimulus response profiles in larval zebrafish, confirming prepulse inhibition phenotypes of two previously isolated mutants, and highlighting best practices for growing larvae prior to behavioral testing. Our new design thus allows rapid construction and streamlined operation of many large-scale behavioral setups with minimal resources and fabrication expertise, with broad applications to other aquatic organisms.

Classification and Quantification of Human Error in Manufacturing: A Case Study in Complex Manual Assembly

Manual assembly operations are sensitive to human errors that can diminish the quality of final products. The paper shows an application of human reliability analysis in a realistic manufacturing context to identify where and why manual assembly errors occur. The techniques SHERPA and HEART were used to perform the analysis of human reliability. Three critical tasks were selected for analysis based on quality records: (1) installation of three types of brackets using fasteners, (2) fixation of a data cable to the assembly structure using cushioned loop clamps and (3) installation of cap covers to protect inlets. The identified error modes with SHERPA were: 36 action errors, nine selection errors, eight information retrieval errors and six checking errors. According to HEART, the highest human error probabilities were associated with assembly parts sensitive to geometry-related errors (brackets and cushioned loop clamps). The study showed that perceptually engaging assembly instructions seem to offer the highest potential for error reduction and performance improvement. Other identified areas of action were the improvement of the inspection process and workers’ provision with better tracking and better feedback. Implementation of assembly guidance systems could potentially benefit worker’s performance and decrease assembly errors.

Sparktope: linear programs from algorithms

In a recent paper, Avis, Bremner, Tiwary and Watanabe gave a method for constructing linear programs (LPs) based on algorithms written in a simple programming language called Sparks. If an algorithm produces the solution x to a problem in polynomial time and space then the LP constructed is also of polynomial size and its optimum solution contains x as well as a complete execution trace of the algorithm. Their method led us to the construction of a compiler called sparktope which we describe in this paper. This compiler allows one to generate polynomial sized LPs for problems in that have exponential extension complexity, such as matching problems in non-bipartite graphs. In this paper, we describe sparktope, the language Sparks, and the assembler instructions and LP constraints it produces. This is followed by two concrete examples, the makespan problem and the problem of testing if a matching in a graph is maximum, both of which are known to have exponential extension complexity. Computational results are given. In discussing these examples, we make use of visualization techniques included in sparktope that may be of independent interest. The extremely large linear programs produced by the compiler appear to be quite challenging to solve using currently available software. Since the optimum LP solutions can be computed independently they may be useful as benchmarks. Further enhancements of the compiler and its application are also discussed.

Tool-based automatic generation of digital assembly instructions

Formal modelling methods can be applied to tackle the complexity of production processes and varying product portfolios particularly affecting SMEs. As part of the project SynDiQuAss a software tool has been developed to automatically generate assembly instructions from a formal process model. Based on a template for a whole product family, the assembly process is decomposed into elementary tasks. In the second step available information such as CAD diagrams, required tools and parts is linked to provide cognitive assistance. The tool-based generation of assembly instructions can thus help increase both productivity and product quality for small lot sizes in manual assembly.

Generation of assembly restrictions and evaluation of assembly criteria from 3D assembly models by collision analysis

The automatic generation of assembly instructions from 3D models in CAD systems is, until this day, not possible. Past research showed that neither feature-based approaches nor disassembly approaches contain enough information to plan assembly sequences autonomously. Based on this, a new approach was developed to combine and extend these two approaches. By the help of a collision analysis and a gravity analysis, assembly restrictions were generated. These assembly restrictions describe the relationship between parts in manner of assembly requirements in an assembly. With this, it is now possible to determine automatically which parts have to be assembled before others can be inserted. Thus, for the first time, assembly restrictions can be used as assembly features and be added to a feature-based approach. Based on this advanced knowledge, new approaches for planning assembly instructions are discussed.

Comparing Effectiveness of Paper Based and Augmented Reality Instructions for Manual Assembly and Training Tasks

Augmented Reality (AR) systems have seen a rapid adaptation in both training and in virtual assembly instructions. AR systems assist the operator by enhancing user perception of reality, reducing the defects, and lead-time. However, there is a significant lack in the existing literature to compare AR systems and conventional work instructions. The aim of this research is to provide an empirical evidence of comparing task completion time, number of errors, workload index and system usability of AR and conventional paper-based work instructions. For this purpose, we designed an experiment where participants use paper based instructions and AR instructions to assemble a planetary gearbox. The task was assessed using NASA-TLX and System Usability Scale (SUS) tests, which allowed further analysis using descriptive statistics. Moreover, the qualitative interview at the end of the experiment gave more insights about participant’s overall experience.