Rate determination from vector observations

Vector observations are a common class of attitude data provided by a wide variety of attitude sensors. Attitude determination from vector observations is a well-understood process and numerous algorithms such as the TRIAD algorithm exist. These algorithms require measurement of the line of site (LOS) vector to reference objects and knowledge of the LOS directions in some predetermined reference frame. Once attitude is determined, it is a simple matter to synthesize vehicle rate using some form of lead-lag filter, and then, use it for vehicle stabilization. Many situations arise, however, in which rate knowledge is required but knowledge of the nominal LOS directions are not available. This paper presents two methods for determining spacecraft angular rates from vector observations without a priori knowledge of the vector directions. The first approach uses an extended Kalman filter with a spacecraft dynamic model and a kinematic model representing the motion of the observed LOS vectors. The second approach uses a 'differential' TRIAD algorithm to compute the incremental direction cosine matrix, from which vehicle rate is then derived

Summer Research Programs Spark Students\u27 Biomedical Interests

No abstract available

ASSESSMENT OF THE PRICE IMPACT OF THE SOUTH CAROLINA CUCUMBER MARKETING ORDER

Demand and Price Analysis,

Integrated restructurable flight control system demonstration results

The purpose of this study was to examine the complementary capabilities of several restructurable flight control system (RFCS) concepts through the integration of these technologies into a complete system. Performance issues were addressed through a re-examination of RFCS functional requirements, and through a qualitative analysis of the design issues that, if properly addressed during integration, will lead to the highest possible degree of fault-tolerant performance. Software developed under previous phases of this contract and under NAS1-18004 was modified and integrated into a complete RFCS subroutine for NASA's B-737 simulation. The integration of these modules involved the development of methods for dealing with the mismatch between the outputs of the failure detection module and the input requirements of the automatic control system redesign module. The performance of this demonstration system was examined through extensive simulation trials

Numbers and Tempo: 1630-1800

After discussing the role of technology in achieving modern performance standards, this article examines sources that have been cited in support of extremely rapid tempos for the time frame 1630-1800. It summarizes recent findings about the French time devices in which a new source ‒ the Paris dancing master Raoul Auger Feuillet’s reasonable pendulum tempo numbers for dance forms ‒ provides the most accurate information to date for tempo around 1700. Continuing then with other sources cited for rapid tempos, the present article discusses the conflicting statements in Marin Mersenne’s Harmonie universelle and his inaccurate pendulum measurements. It considers the tempo implications of the various time signatures, as supplied, for example, by Jean Rousseau and Jacques Hotteterre, together with Saint-Lambert’s idiomatic use of “une fois plus vite” to indicate the signatures’ tempo relationships. The latter’s “walking man” analogy was not a guide for tempo, but a means to convey beat equality; i.e., sound rhythm. Johann Joachim Quantz’s pulsebeat of 80, unworkable in the tempo sense applied today, was intended to teach fast-to-slow gradations of tempo to musicians who lacked any form of time-measuring device. In response, Daniel Gottlob Türk and Johann George Tromlitz cited the many variables that affect tempo. Without the modern technology that makes extreme tempos possible, tempo in earlier centuries had to have been commensurate with the prevailing conditions

Aggregate Price Effects of Institutional Trading: A Study of Mutual Fund Flow and Market Returns

We study the relation between market returns and aggregate flow into U.S. equity funds, using daily flow data. The concurrent daily relation is positive. Our tests show that this concurrent relation reflects flow and institutional trading affecting returns. This daily relation is similar in magnitude to the price impact reported for an individual institution's trades in a stock. Aggregate flow also follows market returns with a one-day lag. The lagged response of flow suggests either a common response of both returns and flow to new information, or positive feedback trading.

Earlier Palliative Care Referrals for Nephrology Patients

Palliative care prevents and relieves suffering through the early identification and treatment of pain and other symptoms, which can be physical, psychosocial, or spiritual (World Health Organization, 2018). It is usually considered a service provided to oncology patients and has positively impacted their treatment. However, it is not as common for many other diseases where the patient would benefit from palliative care involvement. Presently, if palliative care is offered to nephrology patients, it is after they have started dialysis and are having second thoughts whether to continue this treatment plan as it has either become less effective or is interfering with the patient’s quality of life. It has been demonstrated that elderly patients with co-morbidities might only derive limited survival benefits from dialysis Stopping the dialysis usually leads to imminent death, while those on conservative treatment may live up to an additional 23.4 months (Seccareccia & Downar, 2012). Although Scherer et al. (2018), developed an integrated nephrology and palliative care program, others have been slow to adopt this type of care. The focus of this project was to determine by offering palliative care to patients at earlier stages of Chronic Kidney Disease (CKD), would they accept the intervention and think about what they would like as their goals of care? The patient panel of one nephrologist from a large urban medical center in the San Francisco Bay Area was used, and those patients who were at CKD stages 3B or 4 were selected for the project. Those patients on the list who already were on dialysis were on the hospital’s palliative care registry or life care planning registry or had previously had a palliative or life care planning consult were eliminated. This left 26 patients who were contacted, 14 patients made appointments, ten had consults, and four did not keep their appointment. After the consultation, four of the patients stated they were interested in conservative treatment. The youngest of these was 57, and the oldest was 82. All these patients had low Tangri scores, which predicted that they had time before reaching end stage renal disease (ESRD), the point at which they would need dialysis. The project demonstrates that with a palliative care consultation early in the disease process the patient can make informed decisions about their goals of care without being in a crisis state. By explaining to the patient that this is normal care that is ordered by their physician, more patients were willing to accept the consultation, and not think they were being handed a death sentence. These patients received palliative care early enough in their illness, so they had time to decide on their own goals of care and have the opportunity to receive ongoing support as their disease progresses. The National Kidney Foundation (NKF) promotes the use of early palliative care for patients with kidney disease, but the medical community is not always willing to accept conservative treatment as they view dialysis as the gold standard ( Starting or stopping dialysis, 2019). As supported by the literature, early palliative care in any life-limiting disease should be a best practice, just as it is for Oncology patients