Academic literature on the topic '120499 Engineering Design not elsewhere classified'

In recent years, many design approaches have been developed for automated manufacturing systems in the fields of reconfigurable manufacturing systems (RMSs), holonic manufacturing systems (HMSs), and multi-agent systems (MASs). One of the principle reasons for these developments has been to enhance the reconfigurability of a manufacturing system, allowing it to adapt readily to changes over time. However, to date, reconfigurability assessment has been limited. Hence, the efficacy of these design approaches remains inconclusive. This paper is the first of two in this issue to address reconfigurability measurement. Specifically, it seeks to address ‘reconfiguration potential’ by analogy. Mechanical degrees of freedom have been used in the field of mechanics as a means of determining the independent directions of motion of a mechanical system. By analogy, manufacturing degrees of freedom can be used to determine independent ways of production. Furthermore, manufacturing degrees of freedom can be classified into their production and product varieties. This paper specifically focuses on the former to measure the product-independent aspects of manufacturing system ‘reconfiguration potential’. This approach will be added to complementary work on the measurement of ‘reconfiguration ease’ so as to form an integrated reconfigurability measurement process described elsewhere [1—5].

Purpose The purpose of this paper is to investigate the main causes of delay in public construction projects. This is motivated by feedback from public construction experts concerning substantive delays during the last decade. The study thus seeks to help decision makers in Jordan and elsewhere identify problems and develop mitigating strategies. Design/methodology/approach Causes of delay were identified from previous related studies and then augmented after consultation with experts. This resulted in 56 delay factors classified into eight groups. The sampling frame for the study was defined in terms of public construction projects (mostly related to roads) owned by the Ministry of Public Works and Housing in Jordan. A survey was conducted with engineers working as representatives of the owner, contractors or consultants to elicit and evaluate the importance of the 56 delay factors. Findings Overall, 113 completed questionnaire responses were returned and analyzed to rank the causes of delay using the relative importance index method. Owners and consultants showed more interest in factors related to themselves, while contractors showed highest interest in an external factor related to the owner of services. Four recommendations are put forward for decision makers to mitigate against delays. Originality/value This research investigates a relatively large number of delay factors compared to other studies and these are categorized into groups to facilitate thematic understanding. Further, compared to previous related research, this research fills a gap by exploring the opinions of different contract parties.

Teacher talk is a major way in which instructors support and provide scaffolding for their students, frame their pedagogies, model ways of thinking, and convey ideas. Effective teacher talk about engineering design at all levels of students’ educational experiences has the potential to better prepare students for success in engineering and increase the diversity of engineering fields. However, the most effective ways for teachers to talk to their students during engineering design are not well understood. This three-study dissertation examines the ways in which instructors use talk to interact with their students through a variety of different engineering design settings and contexts, with potential implications to improve and educate how teachers present engineering to their students. Overall, this thesis addresses the research question: How do instructors (teachers and professors) use talk interactions to scaffold students in engineering design? The first study is a case study that focuses on the whole class verbal interactions of an experienced and successful teacher throughout the entirety of a month-long life science-based STEM integration unit in a 6th grade classroom. Results show that this teacher’s talk helped to integrate engineering with the science and mathematics content of the unit and modeled the practices of informed designers to help students learn engineering in the context of their science classroom. He framed lessons around problem scoping, incorporated engineering ideas into scientific verbal interactions and aligned individual lessons and the overall unit with the engineering design process. The second study uses naturalistic inquiry to examine how six different teachers of 6^th, 7^th, and 8^th grades talked to their students while the students were actively working in small teams on engineering design projects. Results indicate that the teachers had conversations with the students about many areas of engineering, demonstrating that middle school teachers can have high-level conversations with their students about their design ideas. However, when students struggle to communicate their ideas, the different levels of support outlined in the coding framework and examples provide a structure of support for teachers to give their students. Additionally, there were many areas of engineering that were underemphasized in the teachers’ talk and each teacher had different emphasis. The third study examines how professors in mechanical and biomedical engineering talk to their students during introductory engineering design projects. Results show that the three professors used their talk to support their role as a guide and mentor to students during their projects, although they had different goals with their mentoring. They used their talk to push students’ ideas to consider their problems more broadly, encouraged students to brainstorm diverse out-of-the-box ideas, supported teaming, and modeled engineering language. They maintained a focus on non-technical content, including the iterative nature of design, teaming, and communication, but made references to how students would apply this knowledge in future, more technical projects. The professors supported many challenges for novice designers, including supporting prototype development to represent ideas and iterating to improve their ideas, but were not comprehensive in their support of other challenges, especially problem scoping, testing and troubleshooting, and reflecting on the process. The final chapter of this dissertation presents a synthesis across the three studies and a summary of the implications for teaching. These implications include many examples of high-quality engineering conversations with students at different levels of their education, identification of aspects of engineering education that are underemphasized in teachers’ talk to their students, and connections to needed areas of support and professional development for teachers.

There is significant interest in the used of Steel-plate composite (SC) walls for protective structures, particularly for impactive and impulsive loading. The behavior of SC walls is fundamentally different from that of reinforced concrete (RC) walls due to the addition of steel plates on the exterior surfaces, which prevent concrete scabbing and enhance local perforation resistance.

At present, the combination of high drug development costs and external pressure to lower consumer prices is forcing the pharmaceutical industry to innovate in ways unlike ever before. One of the main drivers of increased productivity in research and development recently has been the application of computational methods to the drug discovery process. While this investment has generated promising insights in many cases, there is still much progress to be made.

The design of a dc generation system is posed as a multi-objective optimization problem which simultaneously designs the generator and the power converter. The proposed design methodology captures the interaction between various system component models and utilizes the system steady state analysis, stability analysis, and disturbance rejection analysis. System mass and power loss are considered as the optimization metrics and minimized. The methodology is demonstrated through the design of a notional dc generation system which contains a Permanent Magnet Synchronous Machine (PMSM), passive rectifier, and a dc-dc converter. To this end, a high fidelity PMSM model, passive rectifier model, semiconductor model and passive component model are developed. The output of optimization is a set of designs forming a Pareto-optimal front. Based on the requirements and the application, a design can be chosen from this set of designs. The methodology is applied to SiC based dc generation system and Si based dc generation system to quantify the advantage of Wide Bandgap (WBG) devices. A prototype SiC based dc generation system is constructed and tested at steady state. Finally a thermal equivalent circuit (TEC) based PMSM thermal model is included in the design paradigm to quantify the impact of the PMSM’s thermal performance to the system design.

Modern computing platforms, from servers to mobile devices, demand ever-increasing amounts of memory to keep up with the growing amounts of data they process, and to bridge the widening processor-memory gap. A large and growing fraction of chip area and energy is expended in memories, which face challenges with technology scaling due to increased leakage, process variations, and unreliability. On the other hand, data intensive workloads such as machine learning and data analytics pose increasing demands on memory systems. Consequently, improving the energy-efficiency and performance of memory systems is an important challenge for computing system designers.

Spintronic memories, which offer several desirable characteristics - near-zero leakage, high density, non-volatility and high endurance - are of great interest for designing future memory systems. However, these memories are not drop-in replacements for current memory technologies, viz. Static Random Access Memory (SRAM) and Dynamic Random Access Memory (DRAM). They pose unique challenges such as variable access times, and require higher write latency and write energy. This dissertation explores new approaches to improving the energy efficiency of spintronic memory systems.

The dissertation first explores the design of approximate memories, in which the need to store and access data precisely is foregone in return for improvements in energy efficiency. This is of particular interest, since many emerging workloads exhibit an inherent ability to tolerate approximations to their underlying computations and data while still producing outputs of acceptable quality. The dissertation proposes that approximate spintronic memories can be realized either by reducing the amount of data that is written to/read from them, or by reducing the energy consumed per access. To reduce memory traffic, the dissertation proposes approximate memory compression, wherein a quality-aware memory controller transparently compresses/decompresses data written to or read from memory. For broader applicability, the quality-aware memory controller can be programmed to specify memory regions that can tolerate approximations, and conforms to a specified error constraint for each such region. To reduce the per-access energy, various mechanisms are identified at the circuit and architecture levels that yield substantial energy benefits at the cost of small probabilities of read, write or retention failures. Based on these mechanisms, a quality-configurable Spin Transfer Torque Magnetic RAM (STT-MRAM) array is designed in which read/write operations can be performed at varying levels of accuracy and energy at runtime, depending on the needs of applications. To illustrate the utility of the proposed quality-configurable memory array, it is evaluated as an L2 cache in the context of a general-purpose processor, and as a scratchpad memory for a domain-specific vector processor.

The dissertation also explores the design of caches with Domain Wall Memory (DWM), a more advanced spintronic memory technology that offers unparalleled density arising from a unique tape-like structure. However, this structure also leads to serialized access to the bits in each bit-cell, resulting in increased access latency, thereby degrading overall performance. To mitigate the performance overheads, the dissertation proposes a reconfigurable DWM-based cache architecture that modulates the active bits per tape with minimal overheads depending on the application's memory access characteristics. The proposed cache is evaluated in a general purpose processor and improvements in performance are demonstrated over both CMOS and previously proposed spintronic caches.

In summary, the dissertation suggests directions to improve the energy efficiency of spintronic memories and re-affirms their potential for the design of future memory systems.

Recent research developments have indicated that asphalt mixture durability and pavement life can be increased by modifying the Superpave asphalt mixture design method to achieve an in-place density of 95%, 2% higher than the conventional density requirements of approximately 93% (7% air voids content). Doing so requires increasing the design air voids content to 5% from the conventional requirement of 4 percent. After successful laboratory testing of this modified mixture design method, known as Superpave 5, two controlled field trials and one full scale demonstration project, the Indiana Department of Transportation (INDOT) let 12 trial projects across the six INDOT districts based on the design method. The Purdue University research team was tasked with observing the implementation of the Superpave 5 mixture design method, documenting the construction and completing an in-depth analysis of the quality control and quality assurance (QC/QA) data obtained from the projects. QC/QA data for each construction project were examined using various statistical metrics to determine construction performance with respect to INDOT Superpave 5 specifications. The data indicate that, on average, the contractors achieved 5% laboratory air voids, which coincides with the Superpave 5 recommendation of 5% laboratory air voids. However, on average, the as-constructed in-place density of 93.8% is roughly 1% less than the INDOT Superpave 5 specification. The findings of this study will benefit the future implementation of this modified mixture design method.

With a stable center of mass, pneumatic-aided movement, and the ability to scale multiple terrain types, the uniquely efficient and lightweight form of spiders has changed the way we think about robotic design. While the number of papers on arachnid biomechanics and spider-based biomimetic robots has been increasing in recent years, the style of analysis and the motion-types analyzed have barely changed since the 1980s. Current analyses are based on a force plate and treadmill design, in which the spider is induced into an escape run. This environmental change can affect the movements of the spider. Here I propose a novel method of testing the biomechanical and kinematic properties of spiders using a tank with a built-in sensor matrix which allows for a more natural environment for the specimens and provides force data from individual legs. The system detects a minimum force of .0196 N and has a sampling rate of 1,000 samples /second, which allows for the analysis of forces during the step. Aphonopelma seemanni, a tarantula commonly used in such research, but whose forces during movement have to date not been analyzed, was recorded walking across the matrix, and the forces, step patterns, joint angles, and center of mass deviations were recorded. Walking indicated significantly different step pattern traits than current literature, and forces per leg (.07281 N±.0235) recorded were much smaller than expected in comparison to other spiders. Statistical analysis also indicated no changes in walking movement over a range of temperatures, which also varies from literature. These findings indicate that further research on spiders should be done with respect to walking gaits in order to improve upon current biomimetic models.

International research has shown that in most countries, there are few women studying towards information technology (IT) careers (Galpin, 2002), and there is much research, particularly in the United States (U.S.), United Kingdom (UK) and Australia into why this is the case (Gürer & Camp, 2002). This article considers the situation in sub-Saharan Africa and focuses on women’s involvement in the generation and creation of information and communication technologies (ICTs) in sub-Saharan Africa, as opposed to ICT use in sub-Saharan Africa, which is considered elsewhere in this volume. There are a number of aspects to the generation and creation of ICTs: how women are involved in this process as IT professionals and how they are educated for these careers, as well how technology can be used appropriately within the specific conditions of sub-Saharan Africa. ICTs will be considered in the broadest sense of the word, covering all electronic technologies, from computers and networking to radio and television. Women’s participation is important: The World Summit on the Information Society (WSIS) Gender Caucus (www.genderwsis.org) has identified women’s involvement in the design and development of technology as well as technology management policy, as key principles for the information society. Marcelle (2001) emphasizes the necessity for African women to become involved in technological and scientific areas, including “computer science, software engineering, network design, network management and related disciplines” (Marcelle, 2001, para. 15) to create an information society appropriate for African women. The diversity of those involved in design leads to higher-quality and more appropriate technological solutions (Borg, 2002; Lazowska, 2002). Background Sub-Saharan Africa has a population of 641 million, young (almost half under 15) and rural (35% urban). Significant problems are undernourishment, poverty and HIV/AIDS (United Nations Development Programme (UNDP), 2004). All the countries in sub-Saharan Africa are classified as developing countries. Some countries are relatively wealthy, such as Mauritius, South Africa, and Nigeria, but have large wealth disparities within their populations. Women in sub-Saharan Africa are expected to focus on the home, they have less access to education and health, and their contribution to family and community is not valued (Huyer, 1997).