Quasiseparable Approach to Evaluating Cubic Splines

The development of fast and efficient algorithms is crucial not only for computer scientists, but also for mathematicians and engineers as those algorithms lead to reduce complexity. Another common interest of these professionals is to construct models using existing data. This leads numerical analysts to explore interpolation techniques. One such technique is called cubic spline interpolation. In here, we will propose a cubic spline solver aiming to bridge the gap between numerical linear algebra, electrical engineering, systems engineering, sensor processing, and parallel processing. We will use quasiseparable structure to evaluate cubic splines by deriving a fast and stable algorithm. The derivation is carried through a specific factorization of the inverse of tridiagonal matrices. This factorization leads to an alternative method to solve the system of tridiagonal matrices as opposed to the existing methods. The proposed algorithm has the lowest computational complexity compared to existing algorithms

Automation and Enhancements to the ERAU OSCOM System Space Situational Awareness

OSCOM, Optical tracking and Spectral characterization of CubeSats for Operational Missions, is a system developed at Embry-Riddle Aeronautical University to produce time-resolved photometry of small satellites using commercial-off-the-shelf hardware. OSCOM has been able to observe resident space objects (RSOs) as small as CubeSats using a Celestron 11” RASA and a CMOS machine vision camera from Allied Vision. By obtaining photometric measurements of satellites, a light curve can be constructed and used to help determine satellite characteristics such as spin rate, satellite state, and even satellite attitude. To enhance the OSCOM system’s ability to observe small satellites, there is ongoing development towards an automated and more capable tracking system. This includes upgrading OSCOM’s tracking software, Auriga, planned development of an automated data analysis software and demonstrating the capabilities of a newly acquired Celestron 14” Edge HD (C14), which can be used for resolved imaging of large satellites and rockets and with a Starizona Hyperstar, and also can be used to observe dimmer RSOs that have low signal to noise ratio when detected by the 11” RASA. This paper discusses the software improvements to the OSCOM system and results acquired from the default C14 and C14 with Hyperstar configurations

Capabilities and Improvements to the OSCOM System

Optical and Spectral characterization of CubeSats for Operational Missions (OSCOM) is a system designed at Embry-Riddle Aeronautical University that uses custom software and inexpensive commercial-off-the-shelf equipment to perform space situational awareness tasks for satellites ranging in size from the International Space Station (ISS) to CubeSats and small orbital debris. OSCOM can provide high frame rate photometry of many small satellites, but has also acquired resolved images of the ISS, planes and rockets. The OSCOM systems is portable and can be deployed to various locations to perform simultaneous multi-point observations to help gather additional information from the satellites observed. Currently, improvements to OSCOM’s tracking program, Auriga, are being made to implement a GUI interface, easier selection of satellites and optical tracking. This poster will discuss both completed and planned improvements to Auriga along with examples of photometry of satellites and resolved images of objects taken with the OSCOM system

Injury patterns in motor-vehicle crashes in the United States: 1998 - 2014

The NASS-CDS database for years 1998-2014 was analyzed to examine trends in injury patterns. To account for changes in data collection for years 2009 and later, most analyses focused on occupants in vehicles newer than 10 years relative to the given crash year. However, for analysis of trends by crash year, the number of occupants injured in older vehicle was estimated. The number of occupants with AIS2+ or AIS3+ injuries was assessed by main crash type (rollover, frontal, rear, near-side, and far-side) and AIS body region (head, face, neck, thorax, spine, abdomen, upper extremity and lower extremity). Risk of AIS2+ or AIS3+ injury was also calculated. Dependent variables include occupant age, BMI, gender, occupant seating position, and restraint; vehicle type and model year; plus crash year. Additional analyses were performed to determine if injury patterns varied within body region. Overall trends in injury indicate a substantial drop in the total number of injuries since 1999. Risk has dropped consistently for near- and far-side crashes, but not for rollovers, frontal, or rear impacts. For AIS3+ injured occupants, the 16% of occupants who are unbelted make up between 45-55% of injured occupants in all crash types except for near-side. Rear occupants have a 1.7 times greater risk of AIS2+ injury in far-side impacts and 2.2 times greater risk in rear impacts compared to front seat occupants, but front occupants have 1.5 times greater risk than rear occupants in frontal crashes. The risk of AIS2+ and AIS3+ injury to all body regions generally increase with age. The proportion of AIS2+ and AIS3+ injured occupants in rollovers decreases with age. In frontal, near-side, and far-side crashes, occupants with AIS2+ injury aged 66 and greater make up a higher proportion of the injured occupants compared to their involvement crashes. Risk of AIS3+ injury is highest in pickup trucks for frontal crashes, near-side and rear crashes and in passenger cars for far-side and rollovers. Risk of AIS2+ and AIS3+ injury is highest in pickup trucks for all AIS body regions. Risk of AIS3+ injury to the pelvis and femur have dropped substantially since vehicle model years 1999-2004.National Highway Traffic Safety Administrationhttp://deepblue.lib.umich.edu/bitstream/2027.42/135950/1/103253.pdfDescription of 103253.pdf : Final repor

Дух міста в добу глобалізації

У статті пропонується авторський варіант осмислення проблем формування та структурування міст з позиції філософської антропології. Зроблено спробу експлікації проблемного поля сучасного міста в контексті дослідження релігійної складової.The article is offered the author version of understanding the problems of forming and structuring town from the position of philosophical anthropology. The attempt of explication of problem field of contemporary town in the context of the religious component of research is done

Cerebral perturbations during exercise in hypoxia.: The brain during hypoxic exercise

International audienceReduction of aerobic exercise performance observed under hypoxic conditions is mainly attributed to altered muscle metabolism due to impaired O(2) delivery. It has been recently proposed that hypoxia-induced cerebral perturbations may also contribute to exercise performance limitation. A significant reduction in cerebral oxygenation during whole body exercise has been reported in hypoxia compared with normoxia, while changes in cerebral perfusion may depend on the brain region, the level of arterial oxygenation and hyperventilation induced alterations in arterial CO(2). With the use of transcranial magnetic stimulation, inconsistent changes in cortical excitability have been reported in hypoxia, whereas a greater impairment in maximal voluntary activation following a fatiguing exercise has been suggested when arterial O(2) content is reduced. Electromyographic recordings during exercise showed an accelerated rise in central motor drive in hypoxia, probably to compensate for greater muscle contractile fatigue. This accelerated development of muscle fatigue in moderate hypoxia may be responsible for increased inhibitory afferent signals to the central nervous system leading to impaired central drive. In severe hypoxia (arterial O(2) saturation <70-75%), cerebral hypoxia per se may become an important contributor to impaired performance and reduced motor drive during prolonged exercise. This review examines the effects of acute and chronic reduction in arterial O(2) (and CO(2)) on cerebral blood flow and cerebral oxygenation, neuronal function, and central drive to the muscles. Direct and indirect influences of arterial deoxygenation on central command are separated. Methodological concerns as well as future research avenues are also considered

Reproducible Research in Signal Processing

Reproducible research results become more and more an important issue as systems under investigation are growing permanently in complexity, and it becomes thus almost impossible to judge the accuracy of research results merely on the bare paper presentation.Peer ReviewedPreprin

Late-time drainage from a sloping Boussinesq aquifer

Numerical solutions to the nonlinear Boussinesq equation, applied to a steeply sloping aquifer and assuming uniform hydraulic conductivity, indicate that late-time recession discharge decreases nearly linearly in time. When recession discharge is characterized by -dQ/dt=aQ[superscript b], this is equivalent to constant dQ/dt or b=0. This result suggests that a previously reported exponential decrease with time (b=1) of modeled recession discharge from a similar sloping aquifer represented by the same equation appears to be an artifact of the numerical solution scheme and its interpretation. Because the linearly decreasing recession discharge (b=0) is not known from field studies, these findings challenge the application of a nonlinear Boussinesq framework assuming uniform conductivity and geometric similarity to infer hydraulic properties of sloping aquifers from observations of streamflow. This finding also questions the validity of the physical interpretation of the exponential decline in late time resulting from the commonly used linearized form of the Boussinesq equation, opposed to the full nonlinear equation, when applied under these conditions. For this reason, application of the linearized equation to infer hydraulic properties of sloping aquifers is also challenged, even if the observed recession is consistent with that of the linearized Boussinesq equation.This is the publisher’s final pdf. The article is copyrighted by the American Geophysical Union and can be found at: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1944-7973.Keywords: Boussinesq, Numerical model, Groundwater, Hillslop

Cerebral hemodynamic and ventilatory responses to hypoxia, hypercapnia, and hypocapnia during 5 days at 4,350 m.

International audienceThis study investigated the changes in cerebral near-infrared spectroscopy (NIRS) signals, cerebrovascular and ventilatory responses to hypoxia and CO2 during altitude exposure. At sea level (SL), after 24 hours and 5 days at 4,350 m, 11 healthy subjects were exposed to normoxia, isocapnic hypoxia, hypercapnia, and hypocapnia. The following parameters were measured: prefrontal tissue oxygenation index (TOI), oxy- (HbO2), deoxy- and total hemoglobin (HbTot) concentrations with NIRS, blood velocity in the middle cerebral artery (MCAv) with transcranial Doppler and ventilation. Smaller prefrontal deoxygenation and larger ΔHbTot in response to hypoxia were observed at altitude compared with SL (day 5: ΔHbO2-0.6±1.1 versus -1.8±1.3 μmol/cmper mm Hg and ΔHbTot 1.4±1.3 versus 0.7±1.1 μmol/cm per mm Hg). The hypoxic MCAv and ventilatory responses were enhanced at altitude. Prefrontal oxygenation increased less in response to hypercapnia at altitude compared with SL (day 5: ΔTOI 0.3±0.2 versus 0.5±0.3% mm Hg). The hypercapnic MCAv and ventilatory responses were decreased and increased, respectively, at altitude. Hemodynamic responses to hypocapnia did not change at altitude. Short-term altitude exposure improves cerebral oxygenation in response to hypoxia but decreases it during hypercapnia. Although these changes may be relevant for conditions such as exercise or sleep at altitude, they were not associated with symptoms of acute mountain sickness