The Huges Array Co-Processor and Its Application to Robotics

This report describes the results of twelve months research involving the Hughes array co-processor. This work began with the testing and debugging of the existing system, continued with the development of software to interface the co-processor to a host machine and concluded with the implementation of a trajectory planning algorithm for redundant manipulators. A loader program has been developed which allows simple programs to be executed. A library of C-callable routines has also been created and this enables the fabrication of more complex systems which require a high level of interaction between the host and co-processor. Routines to perform square root, sine and cosine functions have been designed and these have been used successfully in the development of a trajectory planning algorithm. This algorithm uses the co-processor to compute in parallel a large number of forward kinematics solutions and by doing so is able to convert a cartesian space trajectory into a joint space path for a redundant manipulator. The performance of the processor has been analyzed and a number of recommendations have been made concerning future implementations

Self Organizing Feature Maps and Their Applications to Robotics

The self-organizing feature maps developed by Kohonen appear to capture some of the advantages of the natural systems on which they are based. A summary of the operation of this form of artificial neural network is presented. It was concluded that the primary benefits of using self-organizing feature maps result from their adaptability and plasticity while most problems are largely caused by the lack of a rigorous mathematical foundation. Two different robotics applications are described. In the first, developed by Martinez and Schulten, a hierarchical structure composed of many self-organizing feature maps is used to control a five degree of freedom robot arm. While it was noted that there may be some practical problems, the general idea of using a hierarchical structure appears sound and may be applicable to a wider range of problems. The second robotics application was developed by Saxon and Mukherjee. They used a single self-organizing feature map to learn the motion map of a two degree of freedom arm. The use of such a system should simplify path planning by combining multiple constraints into a 2-D structure

Operating Interaction and Teleprogramming for Subsea Manipulation

The teleprogramming paradigm has been proposed as a means to efficiently perform teleoperation in the subsea environment via an acoustical link. In such a system the effects of both limited bandwidth channels and delayed communications are overcome by transmitting not Cartesian or joint level information but rather symbolic, error-tolerant, program instructions to the remote site. The operator interacts with a virtual reality of the remote site which provides immediate visual and kinesthetic feedback. The uncertainty in this model can be reduced based on information received from the slave manipulator\u27s tactile contact with the environment. It is suggested that the current state of the model be made available to the operator via a graphical display which shows not only the position of objects at the remote site but also, through the use of color clues, the uncertainty associated with those positions. The provision of uncertainty information is important since it allows the operator to compromise between speed and accuracy. An additional operator aid, which we term synthetic fixturing, is proposed. Synthetic fixtures provide the operator of the teleprogramming system with the teleoperation equivalent of the snap commands common in computer aided design programs. By guiding the position and/or orientation of the master manipulator toward specific points, lines or planes the system is able to increase both the speed and precision with which the operator can control the slave arm without requiring sophisticated hardware

Model Based Teleoperation to Eliminate Feedback Delay NSF Grant BCS89-01352 - 3rd Report

We are conducting research in the area of teleoperation with feedback delay. Significant delays occur when performing space teleoperation from the earth as well as in subsea teleoperation where the operator is typically on a surface vessel and communication is via acoustic links. These delays make teleoperation extremely difficult and lead to very low operator productivity. We have combined computer graphics with manipulator programming to provide a solution to the delay problem. A teleoperator master arm is interfaced to a graphical simulation of the remote environment. Synthetic fixtures are used to guide the operators motions and to provide kinesthetic feedback. The operator\u27s actions are monitored and used to generate symbolic motion commands for transmission to, and execution by, the remote slave robot. While much of a task proceeds error free, when an error does occur, the slave system transmits data back to the master environment where the operator can then experience the motion of the slave manipulator in actual task execution. We have also provided for the use of tools such as an impact wrench and a winch at the slave site. In all cases the tools are unencumbered by sensors; the slave uses a compliant instrumented wrist to monitor tool operation in terms of resulting motions and reaction forces

Model Based Teleoperation to Eliminate Feedback Delay NSF Grant BCS89-01352 Second Report

We are conducting research in the area of teleoperation with feedback delay. Delay occurs with earth-based teleoperation in space and with surface-based teleoperation with untethered submersibles when acoustic communication links are involved. The delay in obtaining position and force feedback from remote slave arms makes teleoperation extremely difficult leading to very low productivity. We have combined computer graphics with manipulator programming to provide a solution to the problem. A teleoperator master arm is interfaced to a graphics based simulator of the remote environment. The system is then coupled with a robot manipulator at the remote, delayed site. The operator\u27s actions are monitored to provide both kinesthetic and visual feedback and to generate symbolic motion commands to the remote slave. The slave robot then executes these symbolic commands delayed in time. While much of a task proceeds error free, when an error does occur, the slave system transmits data back to the master environment which is then reset to the error state from which the operator continues the task

The role of STEM-based sustainability in business and management curricula: Exploring cognitive and affective outcomes in university students

To address deficiencies in STEM and sustainability in business management and intra-university curricula, we developed and implemented an interdisciplinary STEM-based sustainability curriculum at a university in the Western United States. Six classes participated in curricular efforts including in-person and online sections of a business management course, in-person and online sections of a general elective STEM course, and a matched control course for each (n = 214). We systematically designed, developed, and implemented curricular interventions—multi-week STEM-based business sustainability modules—using the case teaching method. A comprehensive evaluation with pre- and post-tests was conducted to assess student sustainability cognition and affect. Significant results emerged for sustainability cognition including the environmental, social, and economic dimensions of sustainability. Counterintuitively, student sustainability affect did not improve. However, sustainability cognition and affect were significantly correlated on the post-test for treatment students, an indication that cognitive and affective changes share the same directionality. Discussion, implications, limitations, and future research directions are provided

Integrating and evaluating interdisciplinary sustainability and STEM curriculum in geographical education: A case of three teaching modalities

The effectiveness of interdisciplinary sustainability curriculum remains understudied in geography education. Accordingly, we deployed and evaluated an interdisciplinary sustainability and STEM module for in-person and online sections of a fall 2018 Human Geography course. Results indicate that sustainability knowledge improved after the interdisciplinary curricular intervention irrespective of course modality. Another focus is to explore student reactions to teaching modality due to COVID-19 disruptions. Results indicate that online student sustainability knowledge also improved during COVID-19 (fall 2020). For students in a section converted from in-person to blended, sustainability knowledge did not improve. Implications are provided

Galaxy Cluster Pressure Profiles as Determined by Sunyaev Zel'dovich Effect Observations with MUSTANG and Bolocam I: Joint Analysis Technique

We present a technique to constrain galaxy cluster pressure profiles by jointly fitting Sunyaev-Zel'dovich effect (SZE) data obtained with MUSTANG and Bolocam for the clusters Abell 1835 and MACS0647. Bolocam and MUSTANG probe different angular scales and are thus highly complementary. We find that the addition of the high resolution MUSTANG data can improve constraints on pressure profile parameters relative to those derived solely from Bolocam. In Abell 1835 and MACS0647, we find gNFW inner slopes of $\gamma = 0.36_{-0.21}^{+0.33}$ and $\gamma = 0.38_{-0.25}^{+0.20}$, respectively when $\alpha$ and $\beta$ are constrained to 0.86 and 4.67 respectively. The fitted SZE pressure profiles are in good agreement with X-ray derived pressure profiles.Comment: 12 pages, 12 figures. Submitted to Ap

A Multi-wavelength Study of the Sunyaev-Zel'dovich Effect in the Triple-Merger Cluster MACS J0717.5+3745 with MUSTANG and Bolocam

We present 90, 140, and 268GHz sub-arcminute resolution imaging of the Sunyaev-Zel'dovich effect (SZE) in MACSJ0717.5+3745. Our 90GHz SZE data result in a sensitive, 34uJy/bm map at 13" resolution using MUSTANG. Our 140 and 268GHz SZE imaging, with resolutions of 58" and 31" and sensitivities of 1.8 and 3.3mJy/beam respectively, was obtained using Bolocam. We compare these maps to a 2-dimensional pressure map derived from Chandra X-ray observations. Our MUSTANG data confirm previous indications from Chandra of a pressure enhancement due to shock-heated, >20keV gas immediately adjacent to extended radio emission seen in low-frequency radio maps. The MUSTANG data also detect pressure substructure that is not well-constrained by the X-ray data in the remnant core of a merging subcluster. We find that the small-scale pressure enhancements in the MUSTANG data amount to ~2% of the total pressure measured in the 140GHz Bolocam observations. The X-ray template also fails on larger scales to accurately describe the Bolocam data, particularly at the location of a subcluster known to have a high line of sight optical velocity (~3200km/s). Our Bolocam data are adequately described when we add an additional component - not described by a thermal SZE spectrum - coincident with this subcluster. Using flux densities extracted from our model fits, and marginalizing over the temperature constraints for the region, we fit a thermal+kinetic SZE spectrum to our data and find the subcluster has a best-fit line of sight proper velocity of 3600+3440/-2160km/s. This agrees with the optical velocity estimates for the subcluster. The probability of velocity<0 given our measurements is 2.1%. Repeating this analysis using flux densities measured non-parametrically results in a 3.4% probability of a velocity<=0. We note that this tantalizing result for the kinetic SZE is on resolved, subcluster scales.Comment: 10 Figures, 18 pages. this version corrects issues with the previous arXiv versio

How long does a shoulder replacement last? A systematic review and meta-analysis of case series and national registry reports with more than 10 years of follow-up

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordBackground: Shoulder replacement is an increasingly common treatment for end-stage degenerative shoulder conditions. Some shoulder replacements are unsuccessful and additional operations might be required. It is important for patients and clinicians to know how long shoulder replacements last and how effectively they reduce pain and improve function. This study aims to determine the longevity and long-term efficacy of shoulder replacements. Methods: In this systematic review and meta-analysis, we searched MEDLINE and Embase from their inception to Sept 24, 2019, for case series and registry data reporting 10-year or longer survival of total shoulder replacements, humeral hemiarthroplasties, and reverse total shoulder replacements of a specific brand of implant. Survival, implant, and patient-reported outcome measures data were extracted. The primary outcome was implant survival. We reviewed and analysed national joint replacement registries separately. We weighted each series by SE and calculated a pooled survival estimate at years 10, 15, and 20. For patient-reported outcome measures we pooled the standardised mean difference at 10 years. This study is registered with PROSPERO, CRD42019140221. Findings: 927 non-duplicate articles were identified by our search, nine articles (reporting ten series) were eligible for analysis of survival and six articles were eligible for analysis of patient reported outcomes. The ten series reported all-cause survival of 529 total shoulder replacements and 364 humeral hemiarthroplasties; no series for reverse total shoulder replacement met the inclusion criteria. The estimated 10-year survival for total shoulder replacement was 94·6% (95% CI 93·6–97·6) and humeral hemiarthroplasties was 90·4% (87·0–94·0). A single registry contributed 7651 total shoulder replacements, 1395 humeral hemiarthroplasties, and 7953 reverse total shoulder replacements. The pooled registry 10-year survival was 92·0% (95% CI 91·0–93·0) for total shoulder replacement, 85·5% (83·3–87·7) for humeral hemiarthroplasties, and 94·4% (93·4–95·7) for patients with osteoarthritis who had reverse total shoulder replacement and 93·6% (91·1–95·8) for patients with rotator cuff arthropathy who had reverse total shoulder replacement. Pooled 10-year patient-reported outcome measures showed a substantial improvement from baseline scores, with a standardised mean difference of 2·13 (95% CI 1·93–2·34). Interpretation: Our data show that approximately 90% of shoulder replacements last for longer than 10 years and patient-reported benefits are sustained. Our findings will be of use to surgeons and patients in the informed consent process and to health-care providers for resource planning. Funding: The National Institute for Health Research, the National Joint Registry for England, Wales, Northern Ireland, and Isle of Man, and the Royal College of Surgeons of England.National Institute for Health Research (NIHR)National Joint Registry for England, Wales, Northern Ireland, and Isle of ManRoyal College of Surgeons of Englan