6,194 research outputs found
New Uses for Sensitivity Analysis: How Different Movement Tasks Effect Limb Model Parameter Sensitivity
Get PDFOriginal results for a newly developed eight-order nonlinear limb antagonistic muscle model of elbow flexion and extension are presented. A wider variety of sensitivity analysis techniques are used and a systematic protocol is established that shows how the different methods can be used efficiently to complement one another for maximum insight into model sensitivity. It is explicitly shown how the sensitivity of output behaviors to model parameters is a function of the controller input sequence, i.e., of the movement task. When the task is changed (for instance, from an input sequence that results in the usual fast movement task to a slower movement that may also involve external loading, etc.) the set of parameters with high sensitivity will in general also change. Such task-specific use of sensitivity analysis techniques identifies the set of parameters most important for a given task, and even suggests task-specific model reduction possibilities
Model simulation studies to clarify the effect on saccadic eye movements of initial condition velocities set by the Vestibular Ocular Reflex (VOR)
Get PDFVoluntary active head rotations produced vestibulo-ocular reflex eye movements (VOR) with the subject viewing a fixation target. When this target jumped, the size of the refixation saccades were a function of the ongoing initial velocity of the eye. Saccades made against the VOR were larger in magnitude. Simulation of a reciprocally innervated model eye movement provided results comparable to the experimental data. Most of the experimental effect appeared to be due to linear summation for saccades of 5 and 10 degree magnitude. For small saccades of 2.5 degrees, peripheral nonlinear interaction of state variables in the neuromuscular plant also played a role as proven by comparable behavior in the simulated model with known controller signals
On the Formation of Multiple-Shells Around Asymptotic Giant Branch Stars
Full text linkTwo types of models for the formation of semi-periodic concentric multiple
shells (M-shells) around asymptotic giant branch (AGB) stars and in planetary
nebulae are compared against observations. Models that attribute the M-shells
to processes in an extended wind acceleration zone around AGB stars result in
an optically thick acceleration zone, which reduces the acceleration efficiency
in outer parts of the extended acceleration zone. This makes such models an
unlikely explanation for the formation of M-shells. Models which attribute the
M-shell to semi-periodic variation in one or more stellar properties are most
compatible with observations. The only stellar variation models on time scales
of 50-1500 years that have been suggested are based on an assumed solar-like
magnetic cycle. Although ad-hoc, the magnetic cycle assumption fits naturally
into the increasingly popular view that magnetic activity plays a role in
shaping the wind from upper AGB stars.Comment: 8 pages, Submitted to Ap
Does attending a charter school Reduce the likelihood of being placed into special education? Evidence from Denver, Colorado
Full text linkWe use administrative data to measure whether attending a charter school in Denver, Colorado, reduces the likelihood that students are newly classified as having a disability in primary grades. We employ an observational approach that takes advantage of Denver’s Common Enrollment System, which allows us to observe each school that the student listed a preference to attend. We find evidence that attending a Denver charter school reduces the likelihood that a student is classified as having a specific learning disability, which is the largest and most subjectively diagnosed disability category. We find no evidence that charter attendance reduces the probability of being classified as having a speech or language disability or autism, which are two more objectively diagnosed classifications.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Funding for this research came from The Searle Freedom Trust. (The Searle Freedom Trust)http://sites.bu.edu/marcuswinters/files/2017/09/Does-Charter-Attendence-Reduce-Likelihood-of-SPED-Placement.pdfhttp://sites.bu.edu/marcuswinters/files/2017/09/Does-Charter-Attendence-Reduce-Likelihood-of-SPED-Placement.pdfAccepted manuscrip
Are low-performing students more likely to exit charter schools? Evidence from New York City and Denver, Colorado
Full text linkA common criticism of charter schools is that they systematically remove or “counsel out” their lowest performing students. However, relatively little is currently known about whether low-performing students are in fact more likely to exit charter schools than surrounding traditional public schools. We use longitudinal student-level data from two large urban school systems that prior research has found to have effective charter school sectors–New York City and Denver, Colorado–to evaluate whether there is a differential relationship between low-performance on standardized test scores and the probability that students exit their schools by sector attended. We find no evidence of a differential relationship between prior performance and the likelihood of exiting a school by sector. Low-performing students in both cities are either equally likely or less likely to exit their schools than are student in traditional public schools.We would like to thank the Denver Public School System for providing the data necessary for this paper, and we especially appreciated the assistance of Josh Drake, Yu-lu Hsiung, and Alisha Anuscencion. Funding for this project comes from the Searle Charitable Trust. We thank the Foundation for its support, but acknowledge that the findings and conclusions presented are our own and do not necessarily represent those of the Foundation. All remaining errors are our own. (Searle Charitable Trust)http://sites.bu.edu/marcuswinters/files/2017/09/Exiting-Charter-Schools.pdfAccepted manuscrip
Environmentally Sensitive Land Use Regulation in California
Get PDFAt the Federal and State levels, the National Environmental Policy Act and the California Environmental Quality Act, respectively, require certain procedures before a government takes actions that significantly affect environmental quality. This Article states the case for an environmentally sensitive package involving the National Environmental Policy Act to the California Environmental Quality Act, through Assembly Bill 1301 and the Coastal Zone Initiative, with an eye toward Just v. Marinette County, to permit a review of land use decisions and provide a clear understanding of the limits of environmental protection in California. Because the resulting package involves the National Environmental Policy Act and the California Environmental Quality Act, this Article discusses the policy behind the acts and the statutory language, in addition to the responsibility for preparing and the contents of Environmental Impact Reports. Assembly Bill 1301 and the Coastal Zone Initiative play an intermediary role in this package. Assembly Bill 1301 regulates subdivisions, including any expansion and judicial review. The Coastal Zone Initiative controls the Coastal Zone permit process. This Article advocates the California Environmental Quality Act and the Coastal Zone Initiative as a basis for judicial review of contested Coastal Zone permits. Finally, although the package is fragile, this article concludes that the costs of rejecting such a package are too high
The Evidentiary Value of Defendant’s Safety Rules in a Negligence Action
Get PDFI. Introduction
II. Special Purposes for Admission … A. To Prove Knowledge of Danger … B. To Show Feasibility of Safeguards … C. By Plaintiff to Show Absence of Contributory Negligence … D. By Defendant to Show Plaintiff’s Contributory Negligence … E. Duty to Make Rules and Enforce Them
III. Relation of the Rules to the Standard of Care in Negligence Actions … A. In General … B. As Admissions or Declarations against Interest … C. As a Circumstance under Which the Employee Acts … D. Comparison with Statutes, Ordinances, and Administrative Regulations … 1. A City’s Violation of Its Own Ordinances … E. Comparison with Custom or Habit
IV. Policy Arguments against Admissibility
V. Compliance as Evidence of Due Care
VI. Irrelevant Rules … A. Written Rule Limitation … B. Purpose Limitation … C. Conflict Limitation … D. Interpretation Limitation … E. Time Limitation
VII. Instructions, Weight, and Effect upon Jury in General
VIII. Rules to Prove an Act
IX. The Servant v. Master Class
X. Conclusio
The Pre-Pre-Trial Conference without the Judge in Federal District Courts
Get PDFI. Introduction
II. The Four Rules
III. General Evaluation
IV. Relationship with Other Federal Rules
V. The Hickman Case
VI. Conclusio
- …
