Deogratias Kibira

Virtual reality simulation of a mechanical assembly production line

This paper presents our work on the application of virtual reality simulation to the design of a production line for a mechanically-assembled product. The development of this simulation was undertaken as a part of the Manufacturing Simulation and Visualization Program at the National Institute of Standards and Technology in Gaithersburg, MD. The major research problem is the partitioning and analysis of the assembly operation of the prototype product into different tasks and allocation of these tasks to different assembly workstations. Issues such as cycle times, material handling and assembly line balancing complicate the problem. This paper demonstrates the difficulties of using simulation modeling for concurrent graphical simulation of assembly operations and discrete event analysis of a production process in the same model. It also points out the need to speed up the modeling process and reduce the level of effort required in the construction of a simulation model.

A Virtual Machining Model for Sustainability Analysis

Sustainability has become a very significant research topic since it impacts many different manufacturing industries. The adoption of sustainable manufacturing practices and technologies offers industry a cost effective route to improve economic, environmental, and social performance. As a major manufacturing process, the machining system plays an important role for sustainable manufacturing on the factory floor. Therefore, technologies for monitoring, analyzing, evaluating, and optimizing the sustainability impact of machining systems are critical for decision makers. Modeling and Simulation (M&S) can be an effective tool for success of sustainable manufacturing through its ability to predict the effect of implementing a new facility, process without interrupting real production. This paper introduces a methodology that provides a traditional virtual Numerical Control (NC) machining model with a new capability — to quantitatively analyze the environmental impact of machining system based on Life Cycle Assessment (LCA). The objective of the methodology is to analyze the sustainability impacts of machining process and determine a better plan for improving the sustainable performance of machining system in a virtual environment before work orders are released to the shop floor. Testing different scenarios with simulation models ensures the best setting option available can be chosen. The virtual NC model provides the necessary data for this assessment. In this paper, a list of environmental impact indicators and their metrics has been identified, and modeling elements for sustainable machining have been discussed. Inputs and outputs of the virtual machining model for sustainable machining are described. A case study to experiment the proposed methodology is discussed.

Generic simulation of automotive assembly for interoperability testing

Computer simulation is effective in improving the efficiency of manufacturing system design, operation, and maintenance. Most simulation models are usually tailored to address a narrow set of industrial issues, e.g., the introduction of a new product. If generic data-driven simulations could be developed they would be reusable for wider application including interoperability testing of standards for exchange of data across the supply chain in manufacturing. To facilitate future interoperability testing and training, scientists at the National Institute of Standards and Technology are currently developing distributed, integrated manufacturing simulations for automotive manufacturing. These simulations are being developed at four different levels: the supply chain, the assembly plant, the engineering systems, and the shop floor level. This paper describes the development of a simulation model of the final assembly plant. Future efforts will increase the versatility of the model, run it on neutral data and extend integration with supply chain simulation.

A framework for multi-resolution modeling of sustainable manufacturing

This paper proposes a multi-resolution framework for application of system dynamics modeling to sustainable manufacturing. Sustainable manufacturing involves interaction of four complex systems namely manufacturing, environmental, financial, and social domains. The proposed framework integrates model components corresponding to the four major domains. Conceptual models are proposed at two levels of resolution for each of the four domains with models provided in this paper for the manufacturing domain.

Distributed simulation for interoperability testing along the supply chain

The need for interoperability of information systems among supply chain partners has been recognized. A number of standards have been or are being developed to ensure interoperability of applications used along the supply chain. An associated need for interoperability testing has emerged. There is a need to evaluate compliance of applications to standards across specific platforms. The standards themselves need to be evaluated for a comprehensive coverage of the application scope (validation testing). This paper reports on a distributed simulation based approach for supply chain interoperability testing. Simulations are used to represent real life organizations to serve as sources and consumers of dynamic data. The data can be encapsulated per the standard under consideration and exchanged with other organizations directly or through selected applications for testing. Error free performance of the simulated systems over time will provide confidence in the interoperability of applications and in the standards themselves.

Modeling and simulation analysis types for sustainable manufacturing

Sustainable manufacturing could be promoted by the effective use of Modeling and Simulation (M&S) applications. These applications can evaluate manufacturing operations in light of increasing legislation and awareness for environmental protection. They can help determine the operational policy and strategy, and evaluate day-to-day manufacturing decisions to comply with regulations and to improve a companys image. However, in order to accomplish these objectives, existing and future simulation applications need to be enhanced to include sustainability constructs. This paper describes a classification of M&S application areas along functionality and data requirements axes that are necessary to achieve sustainable manufacturing objectives. The classification can in turn be used to perform requirements analyses for those applications and develop data repositories necessary to build and execute the simulation models.

Ambulance Design Survey 2011: A Summary Report.

Current ambulance designs are ergonomically inefficient and often times unsafe for practical treatment response to medical emergencies. Thus, the patient compartment of a moving ambulance is a hazardous working environment. As a consequence, emergency medical services (EMS) workers suffer fatalities and injuries that far exceed those of the average work place in the United States. To reduce injury and mortality rates in ambulances, the Department of Homeland Security Science and Technology Directorate has teamed with the National Institute of Standards and Technology, the National Institute for Occupational Safety and Health, and BMT Designers & Planners in a joint project to produce science-based ambulance patient compartment design standards. This project will develop new crash-safety design standards and improved user-design interface guidance for patient compartments that are safer for EMS personnel and patients, and facilitate improved patient care. The project team has been working with practitioners, EMS workers’ organizations, and manufacturers to solicit needs and requirements to address related issues. This paper presents an analysis of practitioners’ concerns, needs, and requirements for improved designs elicited through the web-based survey of ambulance design, held by the National Institute of Standards and Technology. This paper also introduces the survey, analyzes the survey results, and discusses recommendations for future ambulance patient compartments design.

Interoperability for virtual manufacturing systems

As manufacturing systems are often costly to develop and operate, simulation technology has been demonstrated to be an effective tool for improving manufacturing system design and the efficiency of manufacturing operations and maintenance. However, effectively and efficiently using simulation remains an important issue in the manufacturing industry. One of the principal reasons is the difficulty in processing, organising, and making use of the production-related information about the manufacturing system to be simulated. The difficulty stemmed from no standard representation for such data, making the effort to input data such as product attributes, processing times, and material quantity requirements into simulations complex, time consuming, and error prone. The core manufacturing simulation data (CMSD) standards, SISO-STD-008-2010 and SISO-STD-008-01-2012, specifically address this data representation issue. CMSD enables the import/export of many different types of factory data into computer simulations and other manufacturing systems. This paper describes the motivation for creating CMSD, standardisation efforts for CMSD, and related research efforts. This paper also describes how CMSD could be used as an integration mechanism in a sustainable manufacturing test-bed being developed at the National Institute of Standards and Technology. The test-bed will be a virtual manufacturing environment to support the testing and validation of sustainability metrics, assessment methods, and tools for use in manufacturing.

Simulation-based design concept evaluation for ambulance patient compartments

To address the inadequacy of ambulance design standards, the Department of Homeland Security Science and Technology Directorate, the National Institute of Standards and Technology, the National Institute for Occupational Safety and Health, and BMT Designers and Planners have collaborated to develop new design standards for ambulance patient compartments. This paper presents a simulation-based approach to evaluate and guide improving patient compartment designs that conform to developed requirements for better performance and safety of ambulance users. Those requirements address hazards stemming from (1) the inability of providers to remain safely restrained while treating patients, and (2) the musculoskeletal damage from awkward body postures. An initial design was developed through the axiomatic design approach with inputs from stakeholders such as emergency medical service providers and ambulance manufacturers. The design was imported into a human task simulation tool. It was tested for performance to identify areas for further improvements, which resulted in a second design concept. This paper shows how computer simulation was used to evaluate the effectiveness of the two successive design concepts in enabling providers to perform a range of medical care tasks while remaining seated and restrained. We also evaluated the musculoskeletal effect of these designs on the providers. The results showed that using a simulation-based evaluation produced patient compartments that better meet user requirements when compared with traditional designs. This research produced a set of requirements and recommendations that we believe will lead to better design standards and guidelines for the next generation of ambulances.

Requirements Analysis for Safer Ambulance Patient Compartments

Abstract Providing emergency care services in the confined space of the patient compartment of a moving ambulance has proven a hazardous activity. A National Institute of Standards & Technology (NIST)/Department of Homeland Security (DHS) project is applying systems engineering approaches to analyze requirements and develop design guidance that will improve Emergency Medical Services (EMS) workers’ safety while optimizing patient care. The analysis of an ambulances patient compartment requires multiple disciplines such as ergonomics and crashworthiness. Systems engineering tools provide a platform to perform the analysis by bridging these disciplines and bringing information sources together. In the first phase of this project we compiled a number of requirements from the results of literature reviews, a nationwide web survey, workshops and focus group meetings. The next phase entails our process for reconciling potentially conflicting requirements from use case scenarios and then determining which constraints and metrics to be used for trade-off analysis and optimization in a human simulation modeling tool. The results of this analysis are being used to develop ambulance patient compartment design recommendations that will be provided as inputs to current and emerging ambulance design standards. In this paper we report on our efforts to provide science-based recommendations that may be used as a basis to revise and enhance current ambulance design standards and practices.