Science.gov

Sample records for compressed work week

  1. A 4-Day Work Week That Works.

    ERIC Educational Resources Information Center

    Walker, Kenneth; Timmerman, Linda

    1980-01-01

    Describes Navarro College's (Corsicana, TX) program to reduce kilowatt hour consumption through alternative energy sources and energy costs through transition to a four-day/40-hour work week. Presents results of studies of employee performance levels, community response, and the cost effectiveness of the program. Lists benefits for the student,…

  2. A 4-Day Work Week That Works.

    ERIC Educational Resources Information Center

    Walker, Kenneth; Timmerman, Linda

    1980-01-01

    Describes Navarro College's (Corsicana, TX) program to reduce kilowatt hour consumption through alternative energy sources and energy costs through transition to a four-day/40-hour work week. Presents results of studies of employee performance levels, community response, and the cost effectiveness of the program. Lists benefits for the student,…

  3. 5 CFR 532.513 - Flexible and compressed work schedules.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Flexible and compressed work schedules... REGULATIONS PREVAILING RATE SYSTEMS Premium Pay and Differentials § 532.513 Flexible and compressed work schedules. Federal Wage System employees who are authorized to work flexible and compressed work...

  4. 2009 Summer 4-Day Work Week Evaluation Report

    ERIC Educational Resources Information Center

    Geneivive, David V.; DeRose, Diego; Ligas, Maria

    2011-01-01

    This report describes the final evaluation of a condensed work schedule, the Summer 2009 4-Day Work Week (S4-DWW), adopted by The School Board of Broward County, Florida. The goal for the program was to close the entire district for 1 day each week to reduce utility costs. Except for a few cases, district schools and offices were closed on Fridays…

  5. 5 CFR 532.513 - Flexible and compressed work schedules.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Flexible and compressed work schedules. 532.513 Section 532.513 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PREVAILING RATE SYSTEMS Premium Pay and Differentials § 532.513 Flexible and compressed work schedules. Federal Wage System employees who...

  6. Teaching and Learning in an 80-Hour Work Week

    PubMed Central

    Wong, Jeffrey G; Holmboe, Eric S; Huot, Stephen J

    2004-01-01

    The 80-hour workweek limit for residents provides an opportunity for residency directors to creatively innovate their programs. Our novel day-float rotation augmented both the educational structure within the inpatient team setting and the ability for house staff to complete their work within the mandated limits. Descriptive evaluation of the rotation was performed through an end-of-rotation questionnaire. The average length of the ward residents’ work week was quantified before and after the rotation's implementation. Educational portfolios and mentored peer-teaching opportunities enriched the rotation. As measured by our evaluation, this new rotation enhanced learning and patient care while reducing work hours for inpatient ward residents. PMID:15109316

  7. 5 CFR 532.513 - Flexible and compressed work schedules.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Flexible and compressed work schedules. 532.513 Section 532.513 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PREVAILING RATE SYSTEMS Premium Pay and Differentials § 532.513 Flexible and compressed...

  8. 5 CFR 610.407 - Premium pay for holiday work for employees on compressed work schedules.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Premium pay for holiday work for employees on compressed work schedules. 610.407 Section 610.407 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Flexible and Compressed Work Schedules § 610.407 Premium pay for holiday work for employees...

  9. Working characteristics of variable intake valve in compressed air engine.

    PubMed

    Yu, Qihui; Shi, Yan; Cai, Maolin

    2014-01-01

    A new camless compressed air engine is proposed, which can make the compressed air energy reasonably distributed. Through analysis of the camless compressed air engine, a mathematical model of the working processes was set up. Using the software MATLAB/Simulink for simulation, the pressure, temperature, and air mass of the cylinder were obtained. In order to verify the accuracy of the mathematical model, the experiments were conducted. Moreover, performance analysis was introduced to design compressed air engine. Results show that, firstly, the simulation results have good consistency with the experimental results. Secondly, under different intake pressures, the highest output power is obtained when the crank speed reaches 500 rpm, which also provides the maximum output torque. Finally, higher energy utilization efficiency can be obtained at the lower speed, intake pressure, and valve duration angle. This research can refer to the design of the camless valve of compressed air engine. PMID:25379536

  10. Working Characteristics of Variable Intake Valve in Compressed Air Engine

    PubMed Central

    Yu, Qihui; Shi, Yan; Cai, Maolin

    2014-01-01

    A new camless compressed air engine is proposed, which can make the compressed air energy reasonably distributed. Through analysis of the camless compressed air engine, a mathematical model of the working processes was set up. Using the software MATLAB/Simulink for simulation, the pressure, temperature, and air mass of the cylinder were obtained. In order to verify the accuracy of the mathematical model, the experiments were conducted. Moreover, performance analysis was introduced to design compressed air engine. Results show that, firstly, the simulation results have good consistency with the experimental results. Secondly, under different intake pressures, the highest output power is obtained when the crank speed reaches 500 rpm, which also provides the maximum output torque. Finally, higher energy utilization efficiency can be obtained at the lower speed, intake pressure, and valve duration angle. This research can refer to the design of the camless valve of compressed air engine. PMID:25379536

  11. 5 CFR 610.407 - Premium pay for holiday work for employees on compressed work schedules.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Premium pay for holiday work for employees on compressed work schedules. 610.407 Section 610.407 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Flexible and Compressed Work Schedules § 610.407...

  12. Birth of the Four-Day Work Week.

    ERIC Educational Resources Information Center

    Hellyer, Lyle

    Indian Hills Community College, faced with rising utility bills dues to inadequate insulation in the campus's older buildings, now utilizes a four-day week during the winter quarter as an energy conservation measure. Planning for the implementation of the four-day week, which began in 1976, was coordinated by an overall energy committee made up of…

  13. Effect of 3 Weeks Use of Compression Garments on Stride and Impact Shock during a Fatiguing Run.

    PubMed

    Lucas-Cuevas, A G; Priego-Quesada, J I; Aparicio, I; Giménez, J V; Llana-Belloch, S; Pérez-Soriano, P

    2015-09-01

    Excessive and prolonged exposure to impact acceleration during running is associated with increased injury rate. Acute use of compressive garments has been speculated to improve attenuation. However, it is unknown how longer interventions of compressive garments influence attenuation in running. 40 runners trained with compressive and placebo stockings for 3 weeks. Perception of comfort, stride parameters (rate, length) and impact acceleration (head and tibial peak acceleration, magnitude, acceleration rate and attenuation) were measured every 5?min during a fatigue run (30?min at 80% of the individual's maximal aerobic speed). Compressive stockings reduced tibial peak acceleration and magnitude compared to placebo stockings at every minute (p<0.05) except for the initial measurement (p>0.05). Moreover, compressive stockings led to a lower rate of increase in tibial peak acceleration (14%, p<0.005) and magnitude (16%, p<0.001) as a result of the development of fatigue compared to placebo stockings (24% and 26% increase, p=0.014 and p=0.003, respectively). Similar perception of comfort was reported for both garments. Training with compressive stockings for 3 weeks reduced impact acceleration and the rate of increase in acceleration compared to placebo stockings. These findings suggest that compressive stockings may play a protective role by reducing impact accelerations during running. PMID:26090880

  14. Here's a Four-day Week That Works.

    ERIC Educational Resources Information Center

    Pompeo, Joe

    1981-01-01

    By lengthening school days and moving to a four-day school week, the Cimarron (New Mexico) School District not only saved energy and transportation costs but also won teacher, student, and parent approval and saw student scores rise on national standardized tests. (RW)

  15. 5 CFR 610.406 - Holiday for employees on compressed work schedules.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Holiday for employees on compressed work schedules. 610.406 Section 610.406 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Flexible and Compressed Work Schedules § 610.406 Holiday for employees on compressed work schedules. (a) If a...

  16. Giving 110%: A Portrait of a Michigan Teacher's Work Week. Policy Report Number 22

    ERIC Educational Resources Information Center

    Burian-Fitzgerald, Marisa; Harris, Debbi

    2004-01-01

    The vast majority of Michigan's teachers work above and beyond their required work week; the average teacher works more than 45 hours per week. The time teachers spend outside regular school hours is often ignored by critics who deride the "short hours and long vacations" enjoyed by teachers. When discussing compensation policies and changes to…

  17. Formation of plasma working fluids for compression by liner implosions

    NASA Astrophysics Data System (ADS)

    Lehr, F. M.; Alaniz, A.; Beason, J. D.; Carswell, L. C.; Degnan, J. H.; Crawford, J. F.; Englert, S. E.; Englert, T. J.; Gahl, J. M.; Holmes, J. H.; Hussey, T. W.; Kiuttu, G. F.; Mullins, B. W.; Peterkin, R. E.; Roderick, N. F.; Turchi, P. J.; Graham, J. D.

    1994-04-01

    Research on the formation of a hot hydrogen working fluid, which may be used in multiple concentric solid-density liner implosions, is reported. In such implosions, an axisymmetric outer liner is driven by a multi-megamp axial discharge, and a coaxial inner liner is driven by a working fluid contained between the liners. The fluid is shocklessly compressed to high pressure as the outer liner implodes around it. In the work reported here a 10 to 100 Torr pressure, hydrogen filled coaxial gun discharge was used to inject plasma into a diagnostic chamber simulating an interliner volume. Spectroscopically determined electron densities of between 1017 and 1018 cm-3 and electron temperatures in the 0.5-2.0 eV range were obtained with a fair degree of reproducibility and symmetry. Two-dimensional, time-dependent magnetohydrodyna- mic computer simulations of the working fluid formation experiment have been performed, and the computations suggest that the present experiment achieves electron number densities and temperatures at the lower extreme of these limits, and neutral densities ˜ 0.3-1.0 ×1019 cm-3. The simulations further suggest that the upper range, and beyond, can be achieved in a more energetic version of the present experiment.

  18. 29 CFR 1926.913 - Blasting in excavation work under compressed air.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Blasting in excavation work under compressed air. 1926.913... Use of Explosives § 1926.913 Blasting in excavation work under compressed air. (a) Detonators and... use in wet holes shall be water-resistant and shall be Fume Class 1. (g) When tunnel excavation...

  19. 29 CFR 1926.913 - Blasting in excavation work under compressed air.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Blasting in excavation work under compressed air. 1926.913... Use of Explosives § 1926.913 Blasting in excavation work under compressed air. (a) Detonators and... use in wet holes shall be water-resistant and shall be Fume Class 1. (g) When tunnel excavation...

  20. 29 CFR 1926.913 - Blasting in excavation work under compressed air.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Blasting in excavation work under compressed air. 1926.913... Use of Explosives § 1926.913 Blasting in excavation work under compressed air. (a) Detonators and... use in wet holes shall be water-resistant and shall be Fume Class 1. (g) When tunnel excavation...

  1. 29 CFR 1926.913 - Blasting in excavation work under compressed air.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Blasting in excavation work under compressed air. 1926.913... Use of Explosives § 1926.913 Blasting in excavation work under compressed air. (a) Detonators and... use in wet holes shall be water-resistant and shall be Fume Class 1. (g) When tunnel excavation...

  2. 5 CFR 610.406 - Holiday for employees on compressed work schedules.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Holiday for employees on compressed work schedules. 610.406 Section 610.406 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Flexible and Compressed Work Schedules § 610.406 Holiday for employees on...

  3. Target compressions by working fluids driven with solid liner implosions

    NASA Technical Reports Server (NTRS)

    Chiang, P.-R.; Lewis, R. A.; Smith, G. A.; Dailey, J. M.; Chakrabarti, S.; Higman, K. I.; Bell, D.; Degnan, J. H.; Hussey, T. W.; Mullins, B. W.

    1994-01-01

    Compression by a spherical solid liner of a gold target surrounded by a hydrogen plasma is simulated. Two-dimensional simulations that treat only a subset of the physics included in the one-dimensional code were performed in an attempt to assess multidimensional effects. A one-dimensional numerical code has been developed to study the effects of thermal radiation and conduction. Results of pressure, density, and energy deposited for different initial plasma conditions are presented and discussed. Results from both one- and two-dimensional codes show that the average target density at peak compression is 39-43 g/cu cm, using the SHIVA Star facility at 90 kV discharge.

  4. Mothers’ Health and Work-Related Factors at 11 Weeks Postpartum

    PubMed Central

    McGovern, Pat; Dowd, Bryan; Gjerdingen, Dwenda; Dagher, Rada; Ukestad, Laurie; McCaffrey, David; Lundberg, Ulf

    2007-01-01

    PURPOSE Many new mothers return to work soon after childbirth. This study examines personal and work-related factors associated with the postpartum health of employed women 11 weeks after childbirth. METHODS Using a prospective cohort design, we recruited 817 Minnesota mothers into the study while they were hospitalized for childbirth in 2001. Telephone interviews were conducted at 5 and 11 weeks postpartum. Eligible women were 18 years or older, employed, and spoke English and gave birth to a singleton infant. Multivariate models using instrumental variables (2-stage least squares) were used to estimate personal and employment characteristics associated with women’s physical and mental health and postpartum symptoms. RESULTS At 11 weeks postpartum, 661 participants (81% of enrollees) completed a full interview, and 50% of participants had returned to work. On average, women reported 4.1 (SD 3.2) childbirth-related symptoms, most frequently fatigue (43%). Factors significantly associated with better health outcomes included better preconception health, the absence of prenatal mood problems, more control over work and home activities, more social support at work and home, and less job stress. CONCLUSIONS The findings suggest postpartum women need to be evaluated regarding their fatigue levels and mental and physical symptoms. Women whose fatigue or postpartum symptoms limit daily role function may find it helpful to have health care clinicians counsel them on strategies to decrease job stress, increase social support at work and home, and certify their use of intermittent family and medical leave to help them manage their symptoms. PMID:18025489

  5. Weekly working hours for Norwegian hospital doctors since 1994 with special attention to postgraduate training, work–home balance and the European Working Time Directive: a panel study

    PubMed Central

    Rosta, Judith; Aasland, Olaf G

    2014-01-01

    Objectives To examine the weekly working hours of Norwegian hospital doctors from 1994 to 2012 with special emphasis on the quality of postgraduate training and work–home balance, and in relation to the requirements of the European Working Time Directive (EWTD). Design Panel study based on postal questionnaires. Setting Norway. Participants Unbalanced cohort of 1300–1600 doctors in 1994, 1995, 1996, 1997, 2000, 2002, 2004, 2006, 2008, 2010 and 2012. Outcome measures Self-reported total weekly working hours and whether 45 weekly working hours are too short, sufficient, or too long to meet the quality requirements of obligatory postgraduate training for junior doctors. Results From 1994 to 2012, the number of weekly working hours was stable for senior (46–47?h) and junior (45–46?h) hospital doctors. In 2012, significantly more senior (27–35%) than junior (11–20%) doctors reported suboptimal work–home balance, defined as working more than 48?h a week. The majority perceived the present situation with an average of 45?h per week for juniors as sufficient for obligatory postgraduate specialist training, but doctors of higher age (OR 1.04, 95% CI 1.01 to 1.08), senior doctors (1.07, 1.04 to 1.11) and doctors working in surgical specialties (OR 1 vs laboratory medicine 0.03, 0.01 to 0.25, internal medicine 0.31, 0.17 to 0.58, psychiatry 0.12, 0.04 to 0.36, paediatrics 0.36, 0.12 to 1.07, anaesthesiology 0.08, 0.02 to 0.39, gynaecology 0.07, 0.01 to 0.56 and others 0.39, 0.04 to 3.56) were more likely to want the work-week to be longer. Conclusions The weekly working hours of Norwegian hospital doctors were always below the EWTD requirements. A significant growth of hospital doctor density over the past two decades, national regulations and cultural values might be important factors. Specialty differences in perception of sufficient training time may call for more flexibility in working time regulations. PMID:25311038

  6. Working fluids selection for fishing boats waste heat powered organic Rankine-vapor compression ice maker

    NASA Astrophysics Data System (ADS)

    Bu, Xianbiao; Wang, Lingbao; Li, Huashan

    2014-10-01

    To utilize waste heat from fishing boats, an organic Rankine cycle/vapor compression cycle system was employed for ice making and a thermodynamic model was developed. Six working fluids were selected and compared in order to identify suitable working fluids which may yield high system efficiencies. The calculated results show that R600a is most suitable working fluid through comprehensive comparison of efficiency, size parameter, pressure ratio, coefficient of performance, system pressure and safety.

  7. Performance Estimation of Absorption/Compression Cycle Using Working Pair Dimethyle Ether/Methanol

    NASA Astrophysics Data System (ADS)

    Endo, Naok; Maeda, Tetsuhiko; Hasegawa, Yasuo

    This paper presents the performance estimation of hybrid absorption/compression heat pump cycle, which use dimethyl ether (DME) and methanol pair as a working fluid. The disadvantage of the DME as a refrigerant is that it is flammable. But it has several advantages from the environmental aspects; toxicity is very low, and GWP is small. The first purpose of this study is to estimate the reduction of the loss of the heat exchangers, by use of absorption/compression cycle. And the second purpose is to lower the working pressure to reduce the possibility of the leakage of the working fluids. Two hybrid systems are supposed as models; one is absorption/compression system with single stage solution circuit, and another is an absorption/compression system with generator/absorber heat exchange cycle. The former cycle exceeds the cooling and heating COPs of pure DME cycle, reducing the maximum pressure about 130 kPa. And the latter system increases the heating COP by 6 to 36% with the working pressure range about 150-260 kPa.

  8. Implementation of Compressed Work Schedules: Participation and Job Redesign as Critical Factors for Employee Acceptance.

    ERIC Educational Resources Information Center

    Latack, Janina C.; Foster, Lawrence W.

    1985-01-01

    Analyzes the effects of an implementation of a three-day/thirty-eight hour (3/38) work schedule among information systems personnel (N=84). Data showed that 18 months after implementation, 3/38 employees still strongly favor the compressed schedule. Data also suggest substantial organizational payoffs including reductions in sick time, overtime,…

  9. On the work distribution for the adiabatic compression of a diluteclassical gas

    SciTech Connect

    Crooks, Gavin E.; Jarzynski, Christopher

    2006-02-23

    We consider the adiabatic and quasi-static compression of adilute classical gas, confined in a piston and initially equilibratedwith a heat bath. We find that the work performed during this process isdescribed statistically by a gamma distribution. We use this result toshow that the model satisfies the non-equilibrium work and fluctuationtheorems, but not the fluctation-dissipation relation. We discuss therare but dominant realizations that contribute most to the exponentialaverage of the work, and relate our results to potentially universal workdistributions.

  10. The 80-hour Work Week for Residents: Views from Obstetric and Gynecology Program Directors

    PubMed Central

    Janoo, Jabin; Hashmi, Mahreen; Seybold, Dara J.; Shapiro, Robert; Calhoun, Byron C.; Bush, Stephen H.

    2015-01-01

    In 2003, the Accreditation Council for Graduate Medical Education mandated an 80-hour work week restriction for residency programs. We examined program directors’ views on how this mandate affects the education of Obstetrics and Gynecology residents. A 25 question survey was administered via Survey Monkey to Obstetrics and Gynecology program directors in the United States over three months in 2011. Fifty program directors (response rate of 28%) completed it with more men (62%) than women (38%) respondents. Overall, only 28% (14/50) responded that the program had improved, with significantly fewer men (5/14; 16.1%) than women (47.4% 9/19; p<0.0169) directors reporting this. There was little perceived improvement in any of the six core ACGME performance objectives and in the CREOG scores, with the improvement ranging from 8% to 12%. In fact, while we observed the percentage of women directors reporting improvement in patient care and interpersonal and communication skills significantly higher compared with their male counterparts, the majority of women still reported either no improvement or a decline in these areas. Though our sample size was small, we found some significant difference between the views of male and female program directors. Both groups nonetheless responded with the majority with a decline or no change rather than a perceived improvement in any of the educational endeavors studied. PMID:25643470

  11. Employment and the Reduction of the Work Week: A Comparison of Seven European Macro-economic Models.

    ERIC Educational Resources Information Center

    van Ginneken, Wouter

    1984-01-01

    Analyzes the impact of a reduced work week on employment, productivity, wages, investment, economic growth, inflation, and government deficits. Concludes that reducing working hours would have greater effect if accompanied by wage reductions and limitation of overtime, but would not affect underlying causes of unemployment. (SK)

  12. Capitol Hill Recognizes National School Psychology Week and the Work of School Psychologists

    ERIC Educational Resources Information Center

    Communique, 2010

    2010-01-01

    In honor of National School Psychology Week, the NASP Government and Professional Relations (GPR) and Communications committees and NASP staff joined forces on a campaign to help elected officials on Capitol Hill learn about the positive contributions of school psychologists and how their services impact student mental health and learning. This…

  13. Capitol Hill Recognizes National School Psychology Week and the Work of School Psychologists

    ERIC Educational Resources Information Center

    Communique, 2010

    2010-01-01

    In honor of National School Psychology Week, the NASP Government and Professional Relations (GPR) and Communications committees and NASP staff joined forces on a campaign to help elected officials on Capitol Hill learn about the positive contributions of school psychologists and how their services impact student mental health and learning. This…

  14. The Time Divide in Cross-National Perspective: The Work Week, Education and Institutions that Matter

    ERIC Educational Resources Information Center

    Frase, Peter; Gornick, Janet C.

    2013-01-01

    Prior empirical studies have found that American workers report longer hours than do workers in other highly industrialized countries, and that the highly educated report the longest hours relative to other educational levels. This paper analyzes disparities in working hours by education levels in 17 high- and middle-income countries to assess…

  15. Aged Mice Have Enhanced Endocortical Response and Normal Periosteal Response Compared With Young-Adult Mice Following 1 Week of Axial Tibial Compression

    PubMed Central

    Brodt, Michael D; Silva, Matthew J

    2010-01-01

    With aging, the skeleton may lose its ability to respond to positive mechanical stimuli. We hypothesized that aged mice are less responsive to loading than young-adult mice. We subjected aged (22 months) and young-adult (7 months) BALB/c male mice to daily bouts of axial tibial compression for 1 week and evaluated cortical and trabecular responses using micro–computed tomography (µCT) and dynamic histomorphometry. The right legs of 95 mice were loaded for 60 rest-inserted cycles per day to 8, 10, or 12 N peak force (generating mid-diaphyseal strains of 900 to 1900 µ? endocortically and 1400 to 3100 µ? periosteally). At the mid-diaphysis, mice from both age groups showed a strong anabolic response on the endocortex (Ec) and periosteum (Ps) [Ec.MS/BS and Ps.MS/BS: loaded (right) versus control (left), p < .05]. Generally, bone formation increased with increasing peak force. At the endocortical surface, contrary to our hypothesis, aged mice had a significantly greater response to loading than young-adult mice (Ec.MS/BS and Ec.BFR/BS: 22 months versus 7 months, p < .001). Responses at the periosteal surface did not differ between age groups (p > .05). The loading-induced increase in bone formation resulted in increased cortical area in both age groups (loaded versus control, p < .05). In contrast to the strong cortical response, loading only weakly stimulated trabecular bone formation. Serial (in vivo) µCT examinations at the proximal metaphysis revealed that loading caused a loss of trabecular bone in 7-month-old mice, whereas it appeared to prevent bone loss in 22-month-old mice. In summary, 1 week of daily tibial compression stimulated a robust endocortical and periosteal bone-formation response at the mid-diaphysis in both young-adult and aged male BALB/c mice. We conclude that aging does not limit the short-term anabolic response of cortical bone to mechanical stimulation in our animal model. © 2010 American Society for Bone and Mineral Research. PMID:20499381

  16. Local Increase of Sleep Slow Wave Activity after Three Weeks of Working Memory Training in Children and Adolescents

    PubMed Central

    Pugin, Fiona; Metz, Andreas J.; Wolf, Martin; Achermann, Peter; Jenni, Oskar G.; Huber, Reto

    2015-01-01

    Study Objectives: Evidence is accumulating that electroencephalographic (EEG) sleep slow wave activity (SWA), the key characteristic of deep sleep, is regulated not only globally, but also locally. Several studies have shown local learning- and use-dependent changes in SWA. In vitro and in vivo animal experiments and studies in humans indicate that these local changes in SWA reflect synaptic plasticity. During maturation, when synaptic changes are most prominent, learning is of utmost importance. Thus, in this study, we aimed to examine whether intensive working memory training for 3 w would lead to a local increase of sleep SWA using high-density EEG recordings in children and young adolescents. Setting: Sleep laboratory at the University Children's Hospital Zurich. Participants: Fourteen healthy subjects between 10 and 16 y. Interventions: Three weeks of intensive working memory training. Measurements and Results: After intensive working memory training, sleep SWA was increased in a small left frontoparietal cluster (11.06 ± 1.24%, mean ± standard error of the mean). In addition, the local increase correlated positively with increased working memory performance assessed immediately (r = 0.66) and 2 to 5 mo (r = 0.68) after the training. Conclusions: The increase in slow wave activity (SWA) correlates with cognitive training-induced plasticity in a region known to be involved in working memory performance. Thus, in future, the mapping of sleep SWA may be used to longitudinally monitor the effects of working memory training in children and adolescents with working memory deficiencies. Citation: Pugin F, Metz AJ, Wolf M, Achermann P, Jenni OG, Huber R. Local increase of sleep slow wave activity after three weeks of working memory training in children and adolescents. SLEEP 2015;38(4):607–614. PMID:25669190

  17. Self-Reported Recovery from 2-Week 12-Hour Shift Work Schedules: A 14-Day Follow-Up

    PubMed Central

    Merkus, Suzanne L.; Holte, Kari Anne; Huysmans, Maaike A.; van de Ven, Peter M.; van Mechelen, Willem; van der Beek, Allard J.

    2015-01-01

    Background Recovery from fatigue is important in maintaining night workers' health. This study compared the course of self-reported recovery after 2-week 12-hour schedules consisting of either night shifts or swing shifts (i.e., 7 night shifts followed by 7 day shifts) to such schedules consisting of only day work. Methods Sixty-one male offshore employees—20 night workers, 16 swing shift workers, and 25 day workers—rated six questions on fatigue (sleep quality, feeling rested, physical and mental fatigue, and energy levels; scale 1–11) for 14 days after an offshore tour. After the two night-work schedules, differences on the 1st day (main effects) and differences during the follow-up (interaction effects) were compared to day work with generalized estimating equations analysis. Results After adjustment for confounders, significant main effects were found for sleep quality for night workers (1.41, 95% confidence interval 1.05–1.89) and swing shift workers (1.42, 95% confidence interval 1.03–1.94) when compared to day workers; their interaction terms were not statistically significant. For the remaining fatigue outcomes, no statistically significant main or interaction effects were found. Conclusion After 2-week 12-hour night and swing shifts, only the course for sleep quality differed from that of day work. Sleep quality was poorer for night and swing shift workers on the 1st day off and remained poorer for the 14-day follow-up. This showed that while working at night had no effect on feeling rested, tiredness, and energy levels, it had a relatively long-lasting effect on sleep quality. PMID:26929834

  18. An old integration scheme for compressible flows revisited, refurbished and put to work

    NASA Technical Reports Server (NTRS)

    Moretti, G.

    1978-01-01

    A scheme for integrating the Euler equations of compressible flow in any hyperbolic case is presented. The scheme relies on the concept of characteristics but is strictly a finite difference scheme. Improvements in accuracy and physical consistence due to the scheme are discussed and results of its application to complex flows are shown.

  19. Methyltransferases do not work by compression, cratic, or desolvation effects, but by electrostatic preorganization

    PubMed Central

    Lameira, Jeronimo; Ram Prasad, B; Chu, Zhen T.; Warshel, Arieh

    2014-01-01

    The enzyme catechol O-methyltransferase (COMT) catalyzes the transfer of a methyl group from S-adenosylmethionine to dopamine and related catechols. The search for the origin of COMT catalysis has led to different proposals and hypothesis, including the entropic, the NAC and the compression proposals as well as the more reasonable electrostatic idea. Thus it is important to understand the catalytic power of this enzyme and to examine the validity of different proposals and in particularly the repeated recent implication of the compression idea. The corresponding analysis should be done by well-defined physically based analysis that involves computations rather than circular interpretations of experimental results. Thus we explore here the origin of the catalytic efficiency of COMT by using the empirical valence bond and the linear response approximation approaches. The results demonstrate that the catalytic effect of COMT is mainly due to electrostatic preorganization effects. It is also shown that the compression, NAC and entropic proposals do not account for the catalytic effect. PMID:25388538

  20. Methyltransferases do not work by compression, cratic, or desolvation effects, but by electrostatic preorganization.

    PubMed

    Lameira, Jeronimo; Bora, Ram Prasad; Chu, Zhen T; Warshel, Arieh

    2015-02-01

    The enzyme catechol O-methyltransferase (COMT) catalyzes the transfer of a methyl group from S-adenosylmethionine to dopamine and related catechols. The search for the origin of COMT catalysis has led to different proposals and hypothesis, including the entropic, the NAC, and the compression proposals as well as the more reasonable electrostatic idea. Thus, it is important to understand the catalytic power of this enzyme and to examine the validity of different proposals and in particular the repeated recent implication of the compression idea. The corresponding analysis should be done by well-defined physically-based considerations that involve computations rather than circular interpretations of experimental results. Thus, we explore here the origin of the catalytic efficiency of COMT by using the empirical valence bond and the linear response approximation approaches. The results demonstrate that the catalytic effect of COMT is mainly due to electrostatic preorganization effects. It is also shown that the compression, NAC and entropic proposals do not account for the catalytic effect. PMID:25388538

  1. Examining the Transition to a Four-Day School Week and Investigating Post-Change Faculty/Staff Work-Life Balance: A Community College Case Study

    ERIC Educational Resources Information Center

    Cardinale, Nelly

    2013-01-01

    This single descriptive embedded case study examined the process of implementing a four-day work/school week at a community college and investigated post-change faculty/staff work-life balance. All of the students attending this college live at home. The change was implemented due to state funding shortfalls, increasing college utility expenses…

  2. Examining the Transition to a Four-Day School Week and Investigating Post-Change Faculty/Staff Work-Life Balance: A Community College Case Study

    ERIC Educational Resources Information Center

    Cardinale, Nelly

    2013-01-01

    This single descriptive embedded case study examined the process of implementing a four-day work/school week at a community college and investigated post-change faculty/staff work-life balance. All of the students attending this college live at home. The change was implemented due to state funding shortfalls, increasing college utility expenses…

  3. 45 CFR 286.90 - How many hours per week must an adult or minor head-of-household participate in work-related...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 2 2012-10-01 2012-10-01 false How many hours per week must an adult or minor... must an adult or minor head-of-household participate in work-related activities to count in the numerator of the work participation rate? During the month, an adult or minor head-of-household...

  4. 45 CFR 286.90 - How many hours per week must an adult or minor head-of-household participate in work-related...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 2 2013-10-01 2012-10-01 true How many hours per week must an adult or minor head... must an adult or minor head-of-household participate in work-related activities to count in the numerator of the work participation rate? During the month, an adult or minor head-of-household...

  5. 45 CFR 286.90 - How many hours per week must an adult or minor head-of-household participate in work-related...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 2 2014-10-01 2012-10-01 true How many hours per week must an adult or minor head... must an adult or minor head-of-household participate in work-related activities to count in the numerator of the work participation rate? During the month, an adult or minor head-of-household...

  6. 45 CFR 286.90 - How many hours per week must an adult or minor head-of-household participate in work-related...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false How many hours per week must an adult or minor... must an adult or minor head-of-household participate in work-related activities to count in the numerator of the work participation rate? During the month, an adult or minor head-of-household...

  7. 45 CFR 286.90 - How many hours per week must an adult or minor head-of-household participate in work-related...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 2 2011-10-01 2011-10-01 false How many hours per week must an adult or minor... must an adult or minor head-of-household participate in work-related activities to count in the numerator of the work participation rate? During the month, an adult or minor head-of-household...

  8. A Week in the Life of Full-Time Office Workers: Work Day and Weekend Light Exposure in Summer and Winter

    PubMed Central

    Crowley, Stephanie J.; Molina, Thomas A.; Burgess, Helen J.

    2014-01-01

    Little is known about the light exposure in full-time office workers, who spend much of their workdays indoors. We examined the 24-hour light exposure patterns of 14 full-time office workers during a week in summer, and assessed their dim light melatonin onset (DLMO, a marker of circadian timing) at the end of the working week. Six workers repeated the study in winter. Season had little impact on the workers' schedules, as the timing of sleep, commute, and work did not vary by more than 30 minutes in the summer and winter. In both seasons, workers received significantly more morning light on workdays than weekends, due to earlier wake times and the morning commute. Evening light in the two hours before bedtime was consistently dim. The timing of the DLMO did not vary between season, and by the end of the working week, the workers slept at a normal circadian phase. PMID:25172304

  9. Human Structure in Six and One-Half Weeks: One Approach to Providing Foundational Anatomical Competency in an Era of Compressed Medical School Anatomy Curricula

    ERIC Educational Resources Information Center

    Halliday, Nancy; O'Donoghue, Daniel; Klump, Kathryn E.; Thompson, Britta

    2015-01-01

    The University of Oklahoma College of Medicine reduced gross anatomy from a full semester, 130-hour course to a six and one-half week, 105-hour course as part of a new integrated systems-based pre-clinical curriculum. In addition to the reduction in contact hours, content from embryology, histology, and radiology were added into the course. The…

  10. Human Structure in Six and One-Half Weeks: One Approach to Providing Foundational Anatomical Competency in an Era of Compressed Medical School Anatomy Curricula

    ERIC Educational Resources Information Center

    Halliday, Nancy; O'Donoghue, Daniel; Klump, Kathryn E.; Thompson, Britta

    2015-01-01

    The University of Oklahoma College of Medicine reduced gross anatomy from a full semester, 130-hour course to a six and one-half week, 105-hour course as part of a new integrated systems-based pre-clinical curriculum. In addition to the reduction in contact hours, content from embryology, histology, and radiology were added into the course. The…

  11. A Poll about Children and Weight: Crunch Time during the American Work and School Week--3 P.M. to Bed. Summary

    ERIC Educational Resources Information Center

    Robert Wood Johnson Foundation, 2013

    2013-01-01

    Childhood obesity is a major public health challenge today, with complex roots interwoven into nearly every facet of American life. This poll addresses one narrow slice of this web: the challenges that families face during the "crunch time" of the work and school week, between 3 p.m. and the time children go to bed. Compared to the school day,…

  12. A Poll about Children and Weight: Crunch Time during the American Work and School Week--3 P.M. to Bed

    ERIC Educational Resources Information Center

    Robert Wood Johnson Foundation, 2013

    2013-01-01

    Childhood obesity is a major public health challenge today, with complex roots interwoven into nearly every facet of American life. This poll addresses one narrow slice of this web: the challenges that families face during the "crunch time" of the work and school week, between 3 pm and the time children go to bed. Compared to the school day, this…

  13. Compression in Visual Working Memory: Using Statistical Regularities to Form More Efficient Memory Representations

    ERIC Educational Resources Information Center

    Brady, Timothy F.; Konkle, Talia; Alvarez, George A.

    2009-01-01

    The information that individuals can hold in working memory is quite limited, but researchers have typically studied this capacity using simple objects or letter strings with no associations between them. However, in the real world there are strong associations and regularities in the input. In an information theoretic sense, regularities…

  14. The dynamical mechanical properties of tungsten under compression at working temperature range of divertors

    NASA Astrophysics Data System (ADS)

    Zhu, C. C.; Song, Y. T.; Peng, X. B.; Wei, Y. P.; Mao, X.; Li, W. X.; Qian, X. Y.

    2016-02-01

    In the divertor structure of ITER and EAST with mono-block module, tungsten plays not only a role of armor material but also a role of structural material, because electromagnetic (EM) impact will be exerted on tungsten components in VDEs or CQ. The EM loads can reach to 100 MN, which would cause high strain rates. In addition, directly exposed to high-temperature plasma, the temperature regime of divertor components is complex. Aiming at studying dynamical response of tungsten divertors under EM loads, an experiment on tungsten employed in EAST divertors was performed using a Kolsky bar system. The testing strain rates and temperatures is derived from actual working conditions, which makes the constitutive equation concluded by using John-Cook model and testing data very accurate and practical. The work would give a guidance to estimate the dynamical response, fatigue life and damage evolution of tungsten divertor components under EM impact loads.

  15. Human Structure in Six and One-Half Weeks: One Approach to Providing Foundational Anatomical Competency in an Era of Compressed Medical School Anatomy curricula

    PubMed Central

    Halliday, Nancy; O'Donoghue, Daniel; Klump, Kathryn E; Thompson, Britta

    2015-01-01

    The University of Oklahoma College of Medicine reduced gross anatomy from a full semester, 130-hour course to a six and one-half week, 105-hour course as part of a new integrated systems-based pre-clinical curriculum. In addition to the reduction in contact hours, content from embryology, histology, and radiology were added into the course. The new curriculum incorporated best practices in the area of regular assessments, feedback, clinical application, multiple teaching modalities, and professionalism. A comparison of the components of the traditional and integrated curriculum, along with end of course evaluations and student performance revealed that the new curriculum was just as effective, if not more effective. This article also provides important lessons learned. Anat Sci Educ 8: 149–157. © 2014 The Authors. Published by Wiley Periodicals, Inc. on behalf of the American Association of Anatomists. PMID:24996159

  16. Staying engaged during the week: the effect of off-job activities on next day work engagement.

    PubMed

    ten Brummelhuis, Lieke L; Bakker, Arnold B

    2012-10-01

    Although studies on employee recovery accumulate at a stunning pace, the commonly used theory (Effort-Recovery model) that explains how recovery occurs has not been explicitly tested. We aimed to unravel the recovery process by examining whether off-job activities enhance next morning vigor to the extent that they enable employees to relax and detach from work. In addition, we investigated whether adequate recovery also helps employees to work with more enthusiasm and vigor on the next workday. On five consecutive days, a total of 74 employees (356 data points) reported the hours they spent on various off-job activities, their feelings of psychological detachment, and feelings of relaxation before going to sleep. Feelings of vigor were reported on the next morning, and day-levels of work engagement were reported after work. As predicted, leisure activities (social, low-effort, and physical activities) increased next morning vigor through enhanced psychological detachment and relaxation. High-duty off-job activities (work and household tasks) reduced vigor because these activities diminished psychological detachment and relaxation. Moreover, off-job activities significantly affected next day work engagement. Our results support the assumption that recovery occurs when employees engage in off-job activities that allow for relaxation and psychological detachment. The findings also underscore the significance of recovery after work: Adequate recovery not only enhances vigor in the morning, but also helps employees to stay engaged during the next workday. PMID:22799771

  17. Age and individual differences in prospective memory during a "Virtual Week": the roles of working memory, vigilance, task regularity, and cue focality.

    PubMed

    Rose, Nathan S; Rendell, Peter G; McDaniel, Mark A; Aberle, Ingo; Kliegel, Matthias

    2010-09-01

    Young (ages 18-22 years) and older (ages 61-87 years) adults (N = 106) played the Virtual Week board game, which involves simulating common prospective memory (PM) tasks of everyday life (e.g., taking medication), and performed working memory (WM) and vigilance tasks. The Virtual Week game includes regular (repeated) and irregular (nonrepeated) PM tasks with cues that are either more or less focal to other ongoing activities. Age differences in PM were reduced for repeated tasks, and performance improved over the course of the week, suggesting retrieval was more spontaneous or habitual. Correlations with WM within each age group were reduced for PM tasks that had more regular or focal cues. WM (but not vigilance) ability was a strong predictor of irregular PM tasks with less focal cues. Taken together, these results support the hypothesis that habitual and focally cued PM tasks are less demanding of attentional resources (specifically, WM), whereas tasks that are more demanding of controlled attentional processes produce larger age differences, which may be attributable to individual differences in WM. PMID:20853967

  18. Age and Individual Differences in Prospective Memory during a “Virtual Week”: The Roles of Working Memory, Vigilance, Task Regularity, and Cue Focality

    PubMed Central

    Rose, Nathan S.; Rendell, Peter G.; McDaniel, Mark A.; Aberle, Ingo; Kliegel, Matthias

    2011-01-01

    Young (ages 18-22) and older (ages 61-87) adults (N=106) played the Virtual Week board game, which involves simulating common prospective memory (PM) tasks of everyday life (e.g., taking medication), and performed working memory (WM) and vigilance tasks. The Virtual Week game includes regular (repeated) and irregular (non-repeated) PM tasks with cues that are either more or less focal to other ongoing activities. Age differences in PM were reduced for repeated tasks and performance improved over the course of the week, suggesting retrieval was more spontaneous or habitual. Correlations with WM within each age group were reduced for PM tasks that had more regular or focal cues. WM (but not vigilance) ability was a strong predictor of irregular PM tasks with less focal cues. Taken together, these results support the hypothesis that habitual and focally-cued PM tasks are less demanding of attentional “resources” (specifically, WM), whereas tasks that are more demanding of controlled attentional processes produce larger age differences, which may be attributable to individual differences in WM. PMID:20853967

  19. Design and implementation of full-frame, bit-allocation image-compression hardware module. Work in progress.

    PubMed

    Ho, B K; Chao, J; Zhu, P; Huang, H K

    1991-05-01

    A hardware module was designed and built to implement the full-frame, bit-allocation image-compression algorithm in a clinical setting. The algorithm transforms an entire image without prepartitioning into small subimages. This adaptation eliminates block artifacts at subimage borders that can mimic relevant pathologic conditions. The quality of 1,024- and 2,048-pixel images compressed at a rate up to 10:1 with a custom-designed processor board (which contains four digital signal processors that transform and quantize separate rows and columns of an image independently with a two-pass cosine transform) and a 16-Mbyte frame buffer was found to be diagnostically acceptable in preliminary receiver operating characteristic studies. The module can compress a 1,024-pixel image in 4 seconds in a general-purpose computer system; images can be compressed in 1 second with the addition of a custom-designed data transporter. Copies of the compression module are being installed in the authors' department and in collaborating hospitals for laboratory and clinical evaluation. PMID:2014312

  20. Compression stockings

    MedlinePLUS

    You wear compression stockings to improve blood flow in your legs. Compression stockings gently squeeze your legs to move ... Wear your compression stockings all day. Your compression stockings should feel strong around your legs. You will ...

  1. Data Compression.

    ERIC Educational Resources Information Center

    Bookstein, Abraham; Storer, James A.

    1992-01-01

    Introduces this issue, which contains papers from the 1991 Data Compression Conference, and defines data compression. The two primary functions of data compression are described, i.e., storage and communications; types of data using compression technology are discussed; compression methods are explained; and current areas of research are…

  2. Doppler ultrasound surveillance in deep tunneling compressed-air work with Trimix breathing: bounce dive technique compared to saturation-excursion technique.

    PubMed

    Vellinga, T P van Rees; Sterk, W; de Boer, A G E M; van der Beek, A J; Verhoeven, A C; van Dijk, F J H

    2008-01-01

    The Western Scheldt Tunneling Project in The Netherlands provided a unique opportunity to evaluate two deep-diving techniques with Doppler ultrasound surveillance. Divers used the bounce diving techniques for repair and maintenance of the TBM. The tunnel boring machine jammed at its deepest depth. As a result the work time was not sufficient. The saturation diving technique was developed and permitted longer work time at great depth. Thirty-one divers were involved in this project. Twenty-three divers were examined using Doppler ultrasound. Data analysis addressed 52 exposures to Trimix at 4.6-4.8 bar gauge using the bounce technique and 354 exposures to Trimix at 4.0-6.9 bar gauge on saturation excursions. No decompression incidents occurred with either technique during the described phase of the project. Doppler ultrasound revealed that the bubble loads assessed in both techniques were generally low. We find out, that despite longer working hours, shorter decompression times and larger physical workloads, the saturation-excursion technique was associated with significant lower bubble grades than in the bounce technique using Doppler Ultrasound. We conclude that the saturation-excursion technique with Trimix is a good option for deep and long exposures in caisson work. The Doppler technique proved valuable, and it should be incorporated in future compressed-air work. PMID:19175196

  3. Compression of spinning plasma

    NASA Astrophysics Data System (ADS)

    Geyko, Vasily; Fisch, Nathaniel

    2014-10-01

    Adiabatic compression of a spinning plasma in cylindrical geometry is studied in thermodynamical limit. Compared to spinning neutral gas, additional electrostatic energy of charge separation yields to increased heat capacity for both axial and longitudinal compressions. Radial compression of plasma with external axial magnetic field is also considered. The obtained results can be used as thermodynamical estimations for z-pinch compression. This work was supported by DOE Contract No. DE-AC02-09CH11466, and by NNSA SSAA Grant No. DE-FG52-08NA28553.

  4. Acting the part. While Cover the Uninsured Week adds star power to its campaign, few viable solutions are in the works.

    PubMed

    Fong, Tony

    2004-05-10

    While Cover the Uninsured Week may have a celebrity spokesman in TV star Noah Wyle, the campaign is still lacking viable legislative solutions. As Sen. Jay Rockefeller, left, noted at a news conference kicking off the event, the "me-first" special interests of the various healthcare trade associations have made putting together a comprehensive approach to the uninsured problem nearly impossible. PMID:15164696

  5. Compressing Aviation Data in XML Format

    NASA Technical Reports Server (NTRS)

    Patel, Hemil; Lau, Derek; Kulkarni, Deepak

    2003-01-01

    Design, operations and maintenance activities in aviation involve analysis of variety of aviation data. This data is typically in disparate formats making it difficult to use with different software packages. Use of a self-describing and extensible standard called XML provides a solution to this interoperability problem. XML provides a standardized language for describing the contents of an information stream, performing the same kind of definitional role for Web content as a database schema performs for relational databases. XML data can be easily customized for display using Extensible Style Sheets (XSL). While self-describing nature of XML makes it easy to reuse, it also increases the size of data significantly. Therefore, transfemng a dataset in XML form can decrease throughput and increase data transfer time significantly. It also increases storage requirements significantly. A natural solution to the problem is to compress the data using suitable algorithm and transfer it in the compressed form. We found that XML-specific compressors such as Xmill and XMLPPM generally outperform traditional compressors. However, optimal use of Xmill requires of discovery of optimal options to use while running Xmill. This, in turn, depends on the nature of data used. Manual disc0ver.y of optimal setting can require an engineer to experiment for weeks. We have devised an XML compression advisory tool that can analyze sample data files and recommend what compression tool would work the best for this data and what are the optimal settings to be used with a XML compression tool.

  6. Relief of Night-time Symptoms Associated With Gastroesophageal Reflux Disease Following 4 Weeks of Treatment With Pantoprazole Magnesium: The Mexican Gastroesophageal Reflux Disease Working Group

    PubMed Central

    Orr, William; Vargas-Romero, José Antonio; Remes-Troche, José María; Morales-Arámbula, Miguel; Soto-Pérez, Julio César; Mateos-Pérez, Gualberto; Sobrino-Cossío, Sergio; Teramoto-Matsubara, Oscar; López-Colombo, Aurelio; Orozco-Gamiz, Antonio; Saez-Ríos, Adolfo; Arellano-Plancarte, Araceli; Chiu-Ugalde, Jazmin; Tholen, Anne; Horbach, Silke; Lundberg, Lars; Fass, Ronnie

    2014-01-01

    Background/Aims To evaluate the effectiveness of pantoprazole magnesium (pantoprazole-Mg) 40 mg in the relief of esophageal and extra-esophageal symptoms of gastroesophageal reflux disease (GERD), particularly night-time symptoms. Methods Patients (aged 18-50 years) with 3-month history of heartburn and/or acid regurgitation plus at least one other symptom in the last week were enrolled in a nationwide, prospective and observational study in Mexico. Patients received pantoprazole-Mg 40 mg once daily during 4 weeks. Symptoms were assessed through a physician-administered structured interview and the patient-completed ReQuest in Practice™ questionnaire. Night-time GERD was defined as arousal from sleep during the night due to GERD-associated symptoms. Results Out of 4,343 patients included at basal visit, 3,665 were considered for the effectiveness per protocol analysis. At baseline, patients had a median of 8 GERD related symptoms. Patients with night-time GERD symptoms (42.7%) were more likely to have extra-esophageal symptoms (P < 0.001) than other GERD patients. Pantoprazole-Mg 40 mg once daily for 4 weeks improved a broad range of GERD-associated symptoms from baseline (80% reduction on physicians assessments; 68-77% reduction on ReQuest in Practice™ dimensions), including both day- and night-time GERD symptoms; improvements were the greatest for extra-esophageal symptoms in patients with night-time symptoms. Pantoprazole-Mg was well tolerated. Conclusions Pantoprazole-Mg 40 mg significantly improved a broad range of esophageal and extra-esophageal GERD related symptoms including sleep disturbances, as well as well-being, in patients with daytime or night-time GERD, making it a good option for patients with GERD, especially when extra-esophageal and night-time symptoms are present. PMID:24466446

  7. Work.

    ERIC Educational Resources Information Center

    Haines, Annette M.

    2003-01-01

    Draws upon Maria Montessori's writings to examine work as a universal human tendency throughout life. Discusses the work of adaptation of the infant, work of "psycho-muscular organism" for the preschooler, work of the imagination for the elementary child, community work of the adolescent, and work of the adult. Asserts that Montessorians' role is…

  8. Compression embedding

    DOEpatents

    Sandford, II, Maxwell T.; Handel, Theodore G.; Bradley, Jonathan N.

    1998-01-01

    A method and apparatus for embedding auxiliary information into the digital representation of host data created by a lossy compression technique and a method and apparatus for constructing auxiliary data from the correspondence between values in a digital key-pair table with integer index values existing in a representation of host data created by a lossy compression technique. The methods apply to data compressed with algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as ordered sequences of blocks containing integer indices having redundancy and uncertainty of value by one unit, allowing indices which are adjacent in value to be manipulated to encode auxiliary data. Also included is a method to improve the efficiency of lossy compression algorithms by embedding white noise into the integer indices. Lossy compression methods use loss-less compression to reduce to the final size the intermediate representation as indices. The efficiency of the loss-less compression, known also as entropy coding compression, is increased by manipulating the indices at the intermediate stage. Manipulation of the intermediate representation improves lossy compression performance by 1 to 10%.

  9. Compression embedding

    DOEpatents

    Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

    1998-07-07

    A method and apparatus for embedding auxiliary information into the digital representation of host data created by a lossy compression technique and a method and apparatus for constructing auxiliary data from the correspondence between values in a digital key-pair table with integer index values existing in a representation of host data created by a lossy compression technique are disclosed. The methods apply to data compressed with algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as ordered sequences of blocks containing integer indices having redundancy and uncertainty of value by one unit, allowing indices which are adjacent in value to be manipulated to encode auxiliary data. Also included is a method to improve the efficiency of lossy compression algorithms by embedding white noise into the integer indices. Lossy compression methods use loss-less compression to reduce to the final size the intermediate representation as indices. The efficiency of the loss-less compression, known also as entropy coding compression, is increased by manipulating the indices at the intermediate stage. Manipulation of the intermediate representation improves lossy compression performance by 1 to 10%. 21 figs.

  10. Compression embedding

    DOEpatents

    Sandford, II, Maxwell T.; Handel, Theodore G.; Bradley, Jonathan N.

    1998-01-01

    A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method.

  11. Compression embedding

    DOEpatents

    Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

    1998-03-10

    A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique is disclosed. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method. 11 figs.

  12. Part-Time Work and Other Flexible Options. ERIC Digest No. 192.

    ERIC Educational Resources Information Center

    Brown, Bettina Lankard

    Options for flexible work schedules such as job sharing, compressed work weeks, reduced hours, work at home, and flextime have provided employees with the means to realize a better balance between work and family and engage simultaneously in more than one endeavor (for example, school and work or two careers). The same options can also lead to…

  13. Modeling Compressed Turbulence

    SciTech Connect

    Israel, Daniel M.

    2012-07-13

    From ICE to ICF, the effect of mean compression or expansion is important for predicting the state of the turbulence. When developing combustion models, we would like to know the mix state of the reacting species. This involves density and concentration fluctuations. To date, research has focused on the effect of compression on the turbulent kinetic energy. The current work provides constraints to help development and calibration for models of species mixing effects in compressed turbulence. The Cambon, et al., re-scaling has been extended to buoyancy driven turbulence, including the fluctuating density, concentration, and temperature equations. The new scalings give us helpful constraints for developing and validating RANS turbulence models.

  14. Space-time compressive imaging.

    PubMed

    Treeaporn, Vicha; Ashok, Amit; Neifeld, Mark A

    2012-02-01

    Compressive imaging systems typically exploit the spatial correlation of the scene to facilitate a lower dimensional measurement relative to a conventional imaging system. In natural time-varying scenes there is a high degree of temporal correlation that may also be exploited to further reduce the number of measurements. In this work we analyze space-time compressive imaging using Karhunen-Loève (KL) projections for the read-noise-limited measurement case. Based on a comprehensive simulation study, we show that a KL-based space-time compressive imager offers higher compression relative to space-only compressive imaging. For a relative noise strength of 10% and reconstruction error of 10%, we find that space-time compressive imaging with 8×8×16 spatiotemporal blocks yields about 292× compression compared to a conventional imager, while space-only compressive imaging provides only 32× compression. Additionally, under high read-noise conditions, a space-time compressive imaging system yields lower reconstruction error than a conventional imaging system due to the multiplexing advantage. We also discuss three electro-optic space-time compressive imaging architecture classes, including charge-domain processing by a smart focal plane array (FPA). Space-time compressive imaging using a smart FPA provides an alternative method to capture the nonredundant portions of time-varying scenes. PMID:22307131

  15. Multichannel Compression

    PubMed Central

    Bor, Stephanie; Souza, Pamela; Wright, Richard

    2008-01-01

    Purpose To clarify if large numbers of wide dynamic range compression channels provide advantages for vowel identification and to measure its acoustic effects. Methods Eight vowels produced by 12 talkers in the /hVd/ context were compressed using 1, 2, 4, 8, and 16 channels. Formant contrast indices (mean formant peak minus mean formant trough; maximum formant peak minus minimum formant trough) were developed to quantify spectral changes. Twenty listeners with mild to moderately severe sensorineural hearing loss identified the compressed vowels in an 8-alternative forced-choice procedure. Results Formant contrast measures revealed significant spectral flattening for 6 of the 8 vowels as channel number increased. A significant decrease in vowel identification performance was also observed as spectral contrast decreased. Conclusions Increasing the number of wide dynamic range compression channels may not be beneficial for all speech signals, and individual vowel identification performance can vary greatly for listeners with similar hearing loss. PMID:18664702

  16. Video Compression

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Optivision developed two PC-compatible boards and associated software under a Goddard Space Flight Center Small Business Innovation Research grant for NASA applications in areas such as telerobotics, telesciences and spaceborne experimentation. From this technology, the company used its own funds to develop commercial products, the OPTIVideo MPEG Encoder and Decoder, which are used for realtime video compression and decompression. They are used in commercial applications including interactive video databases and video transmission. The encoder converts video source material to a compressed digital form that can be stored or transmitted, and the decoder decompresses bit streams to provide high quality playback.

  17. Work.

    PubMed

    Chambers, David W

    2002-01-01

    The very nature of work is changing because of rapid social change, a culture of abundance, and the ability to substitute information for equipment, inventory, and other material aspects of value creation. In America, we are experiencing an erosion of the concept of a "job," a dramatic shift to service and information as the basis for value added, market commercialism, and the importance of the self-managed career. In some of these areas, dentistry has been consistent with the patterns of innovation--even being a model in some cases. There are also areas where dentistry is moving in contrary directions. PMID:12602221

  18. [Compressive therapy of lymphedema].

    PubMed

    Korpan, M I; Chekman, I S; Belova, O H; Fialka-Mozer, V

    2011-01-01

    Lymphedema is a simple complication after mastectomy. On current data there are two main methods of treatment of this disease that include different physical exercises, massage, compression of the edematous tissue and limb bandaging. One of this methods is based on the serial compression of the limb with an intermittent pump that is followed by physical exercises. Another method is known as the complex decongestive therapy (CDP) by Földi. Individual treatment program is worked out for each woman. The positive effect of treatment can be reached after a year of strict adherence to the program. PMID:22606885

  19. Compressed Genotyping

    PubMed Central

    Erlich, Yaniv; Gordon, Assaf; Brand, Michael; Hannon, Gregory J.; Mitra, Partha P.

    2011-01-01

    Over the past three decades we have steadily increased our knowledge on the genetic basis of many severe disorders. Nevertheless, there are still great challenges in applying this knowledge routinely in the clinic, mainly due to the relatively tedious and expensive process of genotyping. Since the genetic variations that underlie the disorders are relatively rare in the population, they can be thought of as a sparse signal. Using methods and ideas from compressed sensing and group testing, we have developed a cost-effective genotyping protocol to detect carriers for severe genetic disorders. In particular, we have adapted our scheme to a recently developed class of high throughput DNA sequencing technologies. The mathematical framework presented here has some important distinctions from the ’traditional’ compressed sensing and group testing frameworks in order to address biological and technical constraints of our setting. PMID:21451737

  20. Astronomical Data Compression: Algorithms and Architectures

    NASA Astrophysics Data System (ADS)

    Seaman, R.; Pence, W.; White, R.; Gaudet, S.

    2010-12-01

    Digital data is the lifeblood of astronomy. Data compression deals with its efficient representation and transport. As focal planes become more crowded and observing cadences more rapid, ever increasing pressure will be applied to realize near-optimum performance. A typical observational workflow comprises many network links and storage nodes, multiplying the advantage of compression dramatically. Recent work on astronomical data compression has focused on the FITS tile compression convention (http://heasarc.gsfcnasa.gov/fitsio/fpack). This birds-of-a-feather session began a broader discussion of compression-aware astronomical data handling architectures, including compression techniques and algorithms appropriate to binary and ASCII catalogs as well as to imaging data.

  1. Astronomical context coder for image compression

    NASA Astrophysics Data System (ADS)

    Pata, Petr; Schindler, Jaromir

    2015-10-01

    Recent lossless still image compression formats are powerful tools for compression of all kind of common images (pictures, text, schemes, etc.). Generally, the performance of a compression algorithm depends on its ability to anticipate the image function of the processed image. In other words, a compression algorithm to be successful, it has to take perfectly the advantage of coded image properties. Astronomical data form a special class of images and they have, among general image properties, also some specific characteristics which are unique. If a new coder is able to correctly use the knowledge of these special properties it should lead to its superior performance on this specific class of images at least in terms of the compression ratio. In this work, the novel lossless astronomical image data compression method will be presented. The achievable compression ratio of this new coder will be compared to theoretical lossless compression limit and also to the recent compression standards of the astronomy and general multimedia.

  2. Effect of internal heating during hot compression testing on the stress-strain behavior and hot working characteristics of Alloy 304L

    SciTech Connect

    Mataya, M.C.; Sackschewsky, V.E.

    1993-05-01

    Temperature change from conversion of deformation to internal heat, and its effect on stress-strain behavior of alloy 304L was investigated by initially isothermal (temperature of specimen, compression dies, environment equilibrated at initiation of test) uniaxial compression. Strain rate was varied 0.01 s{sup {minus}1} to 1 s{sup {minus}1} (thermal state of specimen varied from nearly isothermal to nearly adiabatic). Specimens were deformed at 750 to 1150 to a strain of 1. Change in temperature with strain was calculated via finite element analysis from measured stress-strain data and predictions were confirmed with thermocouples to verify the model. Temperature increased nearly linearly at the highest strain rate, consistent with temperature rise being a linear function of strain (adiabatic). As strain rate was lowered, heat transfer from superheated specimen to cooler dies caused sample temperature to increase and then decrease with strain as the sample thinned and specimen-die contact area increased. As-measured stress was corrected. Resulting isothermal flow curves were compared to predictions of a simplified method suggested by Thomas and Shrinivasan and differences are discussed. Strain rate sensitivity, activation energy for deformation, and flow curve peak associated with onset of dynamic recrystallization were determined from both as-measured and isothermal stress-strain data and found to vary widely. The impact of utilizing as-measured stress-strain data, not corrected for internal heating, on results of a number of published investigations is discussed.

  3. Compressed convolution

    NASA Astrophysics Data System (ADS)

    Elsner, Franz; Wandelt, Benjamin D.

    2014-01-01

    We introduce the concept of compressed convolution, a technique to convolve a given data set with a large number of non-orthogonal kernels. In typical applications our technique drastically reduces the effective number of computations. The new method is applicable to convolutions with symmetric and asymmetric kernels and can be easily controlled for an optimal trade-off between speed and accuracy. It is based on linear compression of the collection of kernels into a small number of coefficients in an optimal eigenbasis. The final result can then be decompressed in constant time for each desired convolved output. The method is fully general and suitable for a wide variety of problems. We give explicit examples in the context of simulation challenges for upcoming multi-kilo-detector cosmic microwave background (CMB) missions. For a CMB experiment with detectors with similar beam properties, we demonstrate that the algorithm can decrease the costs of beam convolution by two to three orders of magnitude with negligible loss of accuracy. Likewise, it has the potential to allow the reduction of disk space required to store signal simulations by a similar amount. Applications in other areas of astrophysics and beyond are optimal searches for a large number of templates in noisy data, e.g. from a parametrized family of gravitational wave templates; or calculating convolutions with highly overcomplete wavelet dictionaries, e.g. in methods designed to uncover sparse signal representations.

  4. MotorWeek

    ScienceCinema

    None

    2013-04-19

    In 2008, PBS's MotorWeek, television's original automotive magazine, visited Argonne's Transportation Technology R&D Center "to learn what it really takes to make clean power sources a viable reality."

  5. MotorWeek

    SciTech Connect

    2009-01-01

    In 2008, PBS's MotorWeek, television's original automotive magazine, visited Argonne's Transportation Technology R&D Center "to learn what it really takes to make clean power sources a viable reality."

  6. Compressive sensing exploiting wavelet-domain dependencies for ECG compression

    NASA Astrophysics Data System (ADS)

    Polania, Luisa F.; Carrillo, Rafael E.; Blanco-Velasco, Manuel; Barner, Kenneth E.

    2012-06-01

    Compressive sensing (CS) is an emerging signal processing paradigm that enables sub-Nyquist sampling of sparse signals. Extensive previous work has exploited the sparse representation of ECG signals in compression applications. In this paper, we propose the use of wavelet domain dependencies to further reduce the number of samples in compressive sensing-based ECG compression while decreasing the computational complexity. R wave events manifest themselves as chains of large coefficients propagating across scales to form a connected subtree of the wavelet coefficient tree. We show that the incorporation of this connectedness as additional prior information into a modified version of the CoSaMP algorithm can significantly reduce the required number of samples to achieve good quality in the reconstruction. This approach also allows more control over the ECG signal reconstruction, in particular, the QRS complex, which is typically distorted when prior information is not included in the recovery. The compression algorithm was tested upon records selected from the MIT-BIH arrhythmia database. Simulation results show that the proposed algorithm leads to high compression ratios associated with low distortion levels relative to state-of-the-art compression algorithms.

  7. COMPRESSION WAVES AND PHASE PLOTS: SIMULATIONS

    SciTech Connect

    Orlikowski, D; Minich, R

    2011-08-01

    Compression wave analysis started nearly 50 years ago with Fowles. Coperthwaite and Williams gave a method that helps identify simple and steady waves. We have been developing a method that gives describes the non-isentropic character of compression waves, in general. One result of that work is a simple analysis tool. Our method helps clearly identify when a compression wave is a simple wave, a steady wave (shock), and when the compression wave is in transition. This affects the analysis of compression wave experiments and the resulting extraction of the high-pressure equation of state.

  8. Scalable ECG Compression for Long-Term Home Health Care.

    PubMed

    Zhang, Tong; Simske, Steven; Blakley, Daniel

    2005-01-01

    Most current Holter devices monitor the ECG for 24 to 72 hours. However, for the accurate diagnosis of many cardiac diseases, especially for the wide variety of asymptomatic cases, continuous ECG monitoring for weeks or even months may be required. In this paper, we focus on the issue of ECG compression during long-term monitoring of the patient. The patient may be at home, at work, or even on a trip. A scalable compression scheme is proposed which ensures optimal signal quality given the limited physical storage on the wearable device. When necessary, the signal quality is progressively and gently degraded in order to adapt to environmental and the patient's conditions. Details of the proposed scheme are described and sample results are presented. PMID:17282196

  9. Compression of echocardiographic scan line data using wavelet packet transform

    NASA Technical Reports Server (NTRS)

    Hang, X.; Greenberg, N. L.; Qin, J.; Thomas, J. D.

    2001-01-01

    An efficient compression strategy is indispensable for digital echocardiography. Previous work has suggested improved results utilizing wavelet transforms in the compression of 2D echocardiographic images. Set partitioning in hierarchical trees (SPIHT) was modified to compress echocardiographic scanline data based on the wavelet packet transform. A compression ratio of at least 94:1 resulted in preserved image quality.

  10. Maxwell's demon and data compression

    NASA Astrophysics Data System (ADS)

    Hosoya, Akio; Maruyama, Koji; Shikano, Yutaka

    2011-12-01

    In an asymmetric Szilard engine model of Maxwell's demon, we show the equivalence between information theoretical and thermodynamic entropies when the demon erases information optimally. The work gain by the engine can be exactly canceled out by the work necessary to reset the demon's memory after optimal data compression in the manner of Shannon before the erasure.

  11. FRESCO: Referential compression of highly similar sequences.

    PubMed

    Wandelt, Sebastian; Leser, Ulf

    2013-01-01

    In many applications, sets of similar texts or sequences are of high importance. Prominent examples are revision histories of documents or genomic sequences. Modern high-throughput sequencing technologies are able to generate DNA sequences at an ever-increasing rate. In parallel to the decreasing experimental time and cost necessary to produce DNA sequences, computational requirements for analysis and storage of the sequences are steeply increasing. Compression is a key technology to deal with this challenge. Recently, referential compression schemes, storing only the differences between a to-be-compressed input and a known reference sequence, gained a lot of interest in this field. In this paper, we propose a general open-source framework to compress large amounts of biological sequence data called Framework for REferential Sequence COmpression (FRESCO). Our basic compression algorithm is shown to be one to two orders of magnitudes faster than comparable related work, while achieving similar compression ratios. We also propose several techniques to further increase compression ratios, while still retaining the advantage in speed: 1) selecting a good reference sequence; and 2) rewriting a reference sequence to allow for better compression. In addition,we propose a new way of further boosting the compression ratios by applying referential compression to already referentially compressed files (second-order compression). This technique allows for compression ratios way beyond state of the art, for instance,4,000:1 and higher for human genomes. We evaluate our algorithms on a large data set from three different species (more than 1,000 genomes, more than 3 TB) and on a collection of versions of Wikipedia pages. Our results show that real-time compression of highly similar sequences at high compression ratios is possible on modern hardware. PMID:24524158

  12. 30 CFR 75.364 - Weekly examination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Weekly examination. 75.364 Section 75.364... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.364 Weekly examination. (a) Worked-out... bleeder system. (b) Hazardous conditions. At least every 7 days, an examination for hazardous...

  13. Efficient Compression of High Resolution Climate Data

    NASA Astrophysics Data System (ADS)

    Yin, J.; Schuchardt, K. L.

    2011-12-01

    resolution climate data can be massive. Those data can consume a huge amount of disk space for storage, incur significant overhead for outputting data during simulation, introduce high latency for visualization and analysis, and may even make interactive visualization and analysis impossible given the limit of the data that a conventional cluster can handle. These problems can be alleviated by with effective and efficient data compression techniques. Even though HDF5 format supports compression, previous work has mainly focused on employ traditional general purpose compression schemes such as dictionary coder and block sorting based compression scheme. Those compression schemes mainly focus on encoding repeated byte sequences efficiently and are not well suitable for compressing climate data consist mainly of distinguished float point numbers. We plan to select and customize our compression schemes according to the characteristics of high-resolution climate data. One observation on high resolution climate data is that as the resolution become higher, values of various climate variables such as temperature and pressure, become closer in nearby cells. This provides excellent opportunities for predication-based compression schemes. We have performed a preliminary estimation of compression ratios of a very simple minded predication-based compression ratio in which we compute the difference between current float point number with previous float point number and then encoding the exponent and significance part of the float point number with entropy-based compression scheme. Our results show that we can achieve higher compression ratios between 2 and 3 in lossless compression, which is significantly higher than traditional compression algorithms. We have also developed lossy compression with our techniques. We can achive orders of magnitude data reduction while ensure error bounds. Moreover, our compression scheme is much more efficient and introduces much less overhead compared to traditaion compression algorithms. Our compression algorithms can also be parallelized easily. We have intergrated our compression algorithms to several simple climate analysis applications. We have carefully pipelined the applications so that the overhead introduced by compression does not undermine the advantage of reducing I/O overhead from compression. Our experimental results show that we improve end-to-end application performance as well as reduce storage requirements with compression.

  14. Efficient lossy compression for compressive sensing acquisition of images in compressive sensing imaging systems.

    PubMed

    Li, Xiangwei; Lan, Xuguang; Yang, Meng; Xue, Jianru; Zheng, Nanning

    2014-01-01

    Compressive Sensing Imaging (CSI) is a new framework for image acquisition, which enables the simultaneous acquisition and compression of a scene. Since the characteristics of Compressive Sensing (CS) acquisition are very different from traditional image acquisition, the general image compression solution may not work well. In this paper, we propose an efficient lossy compression solution for CS acquisition of images by considering the distinctive features of the CSI. First, we design an adaptive compressive sensing acquisition method for images according to the sampling rate, which could achieve better CS reconstruction quality for the acquired image. Second, we develop a universal quantization for the obtained CS measurements from CS acquisition without knowing any a priori information about the captured image. Finally, we apply these two methods in the CSI system for efficient lossy compression of CS acquisition. Simulation results demonstrate that the proposed solution improves the rate-distortion performance by 0.4~2 dB comparing with current state-of-the-art, while maintaining a low computational complexity. PMID:25490597

  15. A Week for Space

    ERIC Educational Resources Information Center

    Comstock, Diane

    2008-01-01

    Space Week focuses on concepts that enable students to make concrete observations in the early grades (K-2) and move to concepts that help students develop their internet research and writing skills in middle and upper grades (Grades 3-5), and culminates with the development of science investigation design skills (Grade 6). To help launch your…

  16. A Week of Observations

    ERIC Educational Resources Information Center

    Colasacco, Jenne

    2011-01-01

    Even the most effective teachers have room to grow, but it's not always easy for principals to give adequate guidance through short observations. High school principal Jenne Colasacco decided to bring more depth to her observations by observing each of her teachers during one class for an entire week. The new observation structure, which included…

  17. Phun Week: Understanding Physiology

    ERIC Educational Resources Information Center

    Limson, Mel; Matyas, Marsha Lakes

    2009-01-01

    Topics such as sports, exercise, health, and nutrition can make the science of physiology relevant and engaging for students. In addition, many lessons on these topics, such as those on the cardiovascular, respiratory, and digestive systems, align with national and state life science education standards. Physiology Understanding Week (PhUn…

  18. Swahili 12 Weeks Course.

    ERIC Educational Resources Information Center

    Defense Language Inst., Washington, DC.

    This 12-weeks course in basic Swahili comprises 55 lesson units in five volumes. The general course format consists of (1) perception drills for comprehension, oral production, and association using "situational picture" illustrations; (2) dialogs in English and Swahili, with cartoon guides; (3) sequenced pattern and recombination drills, and (4)…

  19. Phun Week: Understanding Physiology

    ERIC Educational Resources Information Center

    Limson, Mel; Matyas, Marsha Lakes

    2009-01-01

    Topics such as sports, exercise, health, and nutrition can make the science of physiology relevant and engaging for students. In addition, many lessons on these topics, such as those on the cardiovascular, respiratory, and digestive systems, align with national and state life science education standards. Physiology Understanding Week (PhUn…

  20. Groundmother Earth Week Outreach

    USGS Multimedia Gallery

    Louis Leader Charge demonstrated hydrologic data collection equipment for middle school and high school students at the St. Francis Indian School in St. Francis, SD, on the Rosebud Indian Reservation on April 20, 2015 for UNCI MAKA (Grandmother Earth) week. Louis also provided an overview of USGS ac...

  1. Multilayered image compression

    NASA Astrophysics Data System (ADS)

    Meyer, Francois G.; Averbuch, Amir Z.; Stroemberg, Jan-Olov; Coifman, Ronald R.

    1998-10-01

    The main contribution of this work is a new paradigm for image compression. We describe a new multi-layered representation technique for images. An image is encoded as the superposition of one main approximation, and a sequence of residuals. The strength of the multi-layered method comes from the fact that we use different bases to encode the main approximation and the residuals. For instance, we can use: a wavelet basis to encode a coarse main approximation of the image, wavelet packet bases to encode textured patterns, brushlet bases to encode localized oriented textured features, etc.

  2. Turbulence in Compressible Flows

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Lecture notes for the AGARD Fluid Dynamics Panel (FDP) Special Course on 'Turbulence in Compressible Flows' have been assembled in this report. The following topics were covered: Compressible Turbulent Boundary Layers, Compressible Turbulent Free Shear Layers, Turbulent Combustion, DNS/LES and RANS Simulations of Compressible Turbulent Flows, and Case Studies of Applications of Turbulence Models in Aerospace.

  3. Atomic effect algebras with compression bases

    SciTech Connect

    Caragheorgheopol, Dan; Tkadlec, Josef

    2011-01-15

    Compression base effect algebras were recently introduced by Gudder [Demonstr. Math. 39, 43 (2006)]. They generalize sequential effect algebras [Rep. Math. Phys. 49, 87 (2002)] and compressible effect algebras [Rep. Math. Phys. 54, 93 (2004)]. The present paper focuses on atomic compression base effect algebras and the consequences of atoms being foci (so-called projections) of the compressions in the compression base. Part of our work generalizes results obtained in atomic sequential effect algebras by Tkadlec [Int. J. Theor. Phys. 47, 185 (2008)]. The notion of projection-atomicity is introduced and studied, and several conditions that force a compression base effect algebra or the set of its projections to be Boolean are found. Finally, we apply some of these results to sequential effect algebras and strengthen a previously established result concerning a sufficient condition for them to be Boolean.

  4. Extended testing of compression distillation.

    NASA Technical Reports Server (NTRS)

    Bambenek, R. A.; Nuccio, P. P.

    1972-01-01

    During the past eight years, the NASA Manned Spacecraft Center has supported the development of an integrated water and waste management system which includes the compression distillation process for recovering useable water from urine, urinal flush water, humidity condensate, commode flush water, and concentrated wash water. This paper describes the design of the compression distillation unit, developed for this system, and the testing performed to demonstrate its reliability and performance. In addition, this paper summarizes the work performed on pretreatment and post-treatment processes, to assure the recovery of sterile potable water from urine and treated urinal flush water.

  5. Data compression using Chebyshev transform

    NASA Technical Reports Server (NTRS)

    Cheng, Andrew F. (Inventor); Hawkins, III, S. Edward (Inventor); Nguyen, Lillian (Inventor); Monaco, Christopher A. (Inventor); Seagrave, Gordon G. (Inventor)

    2007-01-01

    The present invention is a method, system, and computer program product for implementation of a capable, general purpose compression algorithm that can be engaged on the fly. This invention has particular practical application with time-series data, and more particularly, time-series data obtained form a spacecraft, or similar situations where cost, size and/or power limitations are prevalent, although it is not limited to such applications. It is also particularly applicable to the compression of serial data streams and works in one, two, or three dimensions. The original input data is approximated by Chebyshev polynomials, achieving very high compression ratios on serial data streams with minimal loss of scientific information.

  6. Microbunching and RF Compression

    SciTech Connect

    Venturini, M.; Migliorati, M.; Ronsivalle, C.; Ferrario, M.; Vaccarezza, C.

    2010-05-23

    Velocity bunching (or RF compression) represents a promising technique complementary to magnetic compression to achieve the high peak current required in the linac drivers for FELs. Here we report on recent progress aimed at characterizing the RF compression from the point of view of the microbunching instability. We emphasize the development of a linear theory for the gain function of the instability and its validation against macroparticle simulations that represents a useful tool in the evaluation of the compression schemes for FEL sources.

  7. Compressed gas manifold

    DOEpatents

    Hildebrand, Richard J. (Edgemere, MD); Wozniak, John J. (Columbia, MD)

    2001-01-01

    A compressed gas storage cell interconnecting manifold including a thermally activated pressure relief device, a manual safety shut-off valve, and a port for connecting the compressed gas storage cells to a motor vehicle power source and to a refueling adapter. The manifold is mechanically and pneumatically connected to a compressed gas storage cell by a bolt including a gas passage therein.

  8. Compression test assembly

    NASA Technical Reports Server (NTRS)

    Kariotis, A. H. (inventor)

    1973-01-01

    A compression test assembly is described which prevents buckling of small diameter rigid specimens undergoing compression testing and permits attachment of extensometers for strain measurements. The test specimen is automatically aligned and laterally supported when compressive force is applied to the end caps and transmitted to the test specimen during testing.

  9. The effects of compression garments on performance of prolonged manual-labour exercise and recovery.

    PubMed

    Chan, Val; Duffield, Rob; Watsford, Mark

    2016-02-01

    This study investigated the effects of wearing compression garments during and 24 h following a 4-h exercise protocol simulating manual-labour tasks. Ten physically trained male participants, familiar with labouring activities, undertook 4 h of work tasks characteristic of industrial workplaces. Participants completed 2 testing sessions, separated by at least 1 week. In the experimental condition, participants wore a full-length compression top and compression shorts during the exercise protocol and overnight recovery, with normal work clothes worn in the control condition. Testing for serum creatine kinase and C-reactive protein, handgrip strength, knee flexion and extension torque, muscle stiffness, perceived muscle soreness and fatigue as well as heart rate and rating of perceived exertion (RPE) responses to 4-min cycling were performed before, following, and 24 h after exercise. Creatine kinase, muscle soreness, and rating of perceived fatigue increased following the exercise protocol (p < 0.05) as did RPE to a standardised cycling warm-up bout. Conversely, no postexercise changes were observed in C-reactive protein, handgrip strength, peak knee flexion torque, or stiffness measures (p > 0.05). Knee extension torque was significantly higher in the control condition at 24 h postexercise (3.1% ± 5.4% change; compression: 2.2% ± 11.1% change), although no other variables were different between conditions at any time. However, compression demonstrated a moderate-large effect (d > 0.60) to reduce perceived muscle soreness, fatigue, and RPE from standardised warm-up at 24 h postexercise. The current findings suggest that compression may assist in perceptual recovery from manual-labour exercise with implications for the ability to perform subsequent work bouts. PMID:26778138

  10. Elective Delivery Before 39 Weeks

    MedlinePLUS

    ... Delivery, and Postpartum Care Elective Delivery Before 39 Weeks • What is a “medically indicated” delivery? • What is ... the baby grow and develop during the last weeks of pregnancy? • What are the risks for babies ...

  11. The New CCSDS Image Compression Recommendation

    NASA Technical Reports Server (NTRS)

    Yeh, Pen-Shu; Armbruster, Philippe; Kiely, Aaron B.; Masschelein, Bart; Moury, Gilles; Schafer, Christoph

    2004-01-01

    The Consultative Committee for Space Data Systems (CCSDS) data compression working group has recently adopted a recommendation for image data compression, with a final release expected in 2005. The algorithm adopted in the recommendation consists a two dimensional discrete wavelet transform of the image, followed by progressive bit-plane coding of the transformed data. The algorithm can provide both lossless and lossy compression, and allows a user to directly control the compressed data volume or the fidelity with which the wavelet-transformed data can be reconstructed. The algorithm is suitable for both frame-based image data and scan-based sensor data, and has applications for near-earth and deep-space missions. The standard will be accompanied by free software sources on a future web site. An ASIC implementation of the compressor is currently under development. This paper describes the compression algorithm along with the requirements that drove the selection of the algorithm.

  12. Adaptive compressive sensing camera

    NASA Astrophysics Data System (ADS)

    Hsu, Charles; Hsu, Ming K.; Cha, Jae; Iwamura, Tomo; Landa, Joseph; Nguyen, Charles; Szu, Harold

    2013-05-01

    We have embedded Adaptive Compressive Sensing (ACS) algorithm on Charge-Coupled-Device (CCD) camera based on the simplest concept that each pixel is a charge bucket, and the charges comes from Einstein photoelectric conversion effect. Applying the manufactory design principle, we only allow altering each working component at a minimum one step. We then simulated what would be such a camera can do for real world persistent surveillance taking into account of diurnal, all weather, and seasonal variations. The data storage has saved immensely, and the order of magnitude of saving is inversely proportional to target angular speed. We did design two new components of CCD camera. Due to the matured CMOS (Complementary metal-oxide-semiconductor) technology, the on-chip Sample and Hold (SAH) circuitry can be designed for a dual Photon Detector (PD) analog circuitry for changedetection that predicts skipping or going forward at a sufficient sampling frame rate. For an admitted frame, there is a purely random sparse matrix [?] which is implemented at each bucket pixel level the charge transport bias voltage toward its neighborhood buckets or not, and if not, it goes to the ground drainage. Since the snapshot image is not a video, we could not apply the usual MPEG video compression and Hoffman entropy codec as well as powerful WaveNet Wrapper on sensor level. We shall compare (i) Pre-Processing FFT and a threshold of significant Fourier mode components and inverse FFT to check PSNR; (ii) Post-Processing image recovery will be selectively done by CDT&D adaptive version of linear programming at L1 minimization and L2 similarity. For (ii) we need to determine in new frames selection by SAH circuitry (i) the degree of information (d.o.i) K(t) dictates the purely random linear sparse combination of measurement data a la [?]M,N M(t) = K(t) Log N(t).

  13. Comparison of Artificial Compressibility Methods

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin; Housman, Jeffrey; Kwak, Dochan

    2003-01-01

    Various artificial compressibility methods for calculating three-dimensional, steady and unsteady, laminar and turbulent, incompressible Navier-Stokes equations are compared in this work. Each method is described in detail along with appropriate physical and numerical boundary conditions. Analysis of well-posedness and numerical solutions to test problems for each method are provided. A comparison based on convergence behavior, accuracy, stability and robustness is used to establish the relative positive and negative characteristics of each method.

  14. Compressed domain indexing of losslessly compressed images

    NASA Astrophysics Data System (ADS)

    Schaefer, Gerald

    2001-12-01

    Image retrieval and image compression have been pursued separately in the past. Only little research has been done on a synthesis of the two by allowing image retrieval to be performed directly in the compressed domain of images without the need to uncompress them first. In this paper methods for image retrieval in the compressed domain of losslessly compressed images are introduced. While most image compression techniques are lossy, i.e. discard visually less significant information, lossless techniques are still required in fields like medical imaging or in situations where images must not be changed due to legal reasons. The algorithms in this paper are based on predictive coding methods where a pixel is encoded based on the pixel values of its (already encoded) neighborhood. The first method is based on an understanding that predictively coded data is itself indexable and represents a textural description of the image. The second method operates directly on the entropy encoded data by comparing codebooks of images. Experiments show good image retrieval results for both approaches.

  15. Intelligent bandwidth compression

    NASA Astrophysics Data System (ADS)

    Van Nevel, Alan J.; Creusere, Charles D.

    1999-10-01

    In this paper we present a novel synthesis of embedded compression and texture recognition. In order to maximize the information content of a transmitted image, a texture recognition and segmentation algorithm is used to identify potential areas of disinterest, and the compression algorithm regionally compresses the image, allocating fewer bits to textured regions. In this method, higher resolution is achieved in areas that potentially are of more interest to a viewer.

  16. Compressed Media: A New Dimension of Compressed Speech.

    ERIC Educational Resources Information Center

    Hartjen, Raymond H.

    Through the use of the Information Mapping and Information Blocking format, this paper discusses various means of increasing the information availability rate through compressed media. Techniques reviewed include: compressed speech, compressed media for individualization of instruction, compressed speech and remedial reading, speech compression…

  17. A static architecture for compressive target tracking

    NASA Astrophysics Data System (ADS)

    Poon, Phillip K.; Townsend, Daniel; Wehrwein, Scott; Vera, Esteban M.; Stenner, Michael D.; Gehm, Michael E.

    2012-06-01

    Traditional approaches to persistent surveillance generate prodigious amounts of data, stressing storage, communication, and analysis systems. As such, they are well suited for compressed sensing (CS) concepts. Existing demonstrations of compressive target tracking have utilized time-sequences of random patterns, an approach that is sub-optimal for real world dynamic scenes. We have been investigating an alternative architecture that we term SCOUT-the Static Computational Optical Undersampled Tracker-which uses a pair of static masks and a defocused detector to acquire a small number of measurements in parallel. We will report on our working prototypes that have demonstrated successful target tracking at 16x compression.

  18. Compressed Gas Safety for Experimental Fusion Facilities

    SciTech Connect

    Lee C. Cadwallader

    2004-09-01

    Experimental fusion facilities present a variety of hazards to the operators and staff. There are unique or specialized hazards, including magnetic fields, cryogens, radio frequency emissions, and vacuum reservoirs. There are also more general industrial hazards, such as a wide variety of electrical power, pressurized air, and cooling water systems in use, there are crane and hoist loads, working at height, and handling compressed gas cylinders. This paper outlines the projectile hazard assoicated with compressed gas cylinders and mthods of treatment to provide for compressed gas safety. This information should be of interest to personnel at both magnetic and inertial fusion experiments.

  19. Compression of digital holographic data: an overview

    NASA Astrophysics Data System (ADS)

    Dufaux, Frederic; Xing, Yafei; Pesquet-Popescu, Beatrice; Schelkens, Peter

    2015-09-01

    Holography has the potential to become the ultimate 3D experience. Nevertheless, in order to achieve practical working systems, major scientific and technological challenges have to be tackled. In particular, as digital holographic data represents a huge amount of information, the development of efficient compression techniques is a key component. This problem has gained significant attention by the research community during the last 10 years. Given that holograms have very different signal properties when compared to natural images and video sequences, existing compression techniques (e.g. JPEG or MPEG) remain suboptimal, calling for innovative compression solutions. In this paper, we will review and analyze past and on-going work for the compression of digital holographic data.

  20. Does Work Experience Actually Work?

    ERIC Educational Resources Information Center

    Field, John

    2012-01-01

    As unemployment levels rise, so education and training move into the policy spotlight. For the government, this is a very uncomfortable place to be right now. A number of large companies have withdrawn from the flagship Work Programme--under which jobseekers are invited to take up unpaid work placements of between two and eight weeks--amid…

  1. Does Work Experience Actually Work?

    ERIC Educational Resources Information Center

    Field, John

    2012-01-01

    As unemployment levels rise, so education and training move into the policy spotlight. For the government, this is a very uncomfortable place to be right now. A number of large companies have withdrawn from the flagship Work Programme--under which jobseekers are invited to take up unpaid work placements of between two and eight weeks--amid…

  2. 26. Central compression lock, north span facing north. Compression lock ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. Central compression lock, north span facing north. Compression lock locks two spans together at highest point. There are three compression locks. - Henry Ford Bridge, Spanning Cerritos Channel, Los Angeles-Long Beach Harbor, Los Angeles, Los Angeles County, CA

  3. Aerodynamics inside a rapid compression machine

    SciTech Connect

    Mittal, Gaurav; Sung, Chih-Jen

    2006-04-15

    The aerodynamics inside a rapid compression machine after the end of compression is investigated using planar laser-induced fluorescence (PLIF) of acetone. To study the effect of reaction chamber configuration on the resulting aerodynamics and temperature field, experiments are conducted and compared using a creviced piston and a flat piston under varying conditions. Results show that the flat piston design leads to significant mixing of the cold vortex with the hot core region, which causes alternate hot and cold regions inside the combustion chamber. At higher pressures, the effect of the vortex is reduced. The creviced piston head configuration is demonstrated to result in drastic reduction of the effect of the vortex. Experimental conditions are also simulated using the Star-CD computational fluid dynamics package. Computed results closely match with experimental observation. Numerical results indicate that with a flat piston design, gas velocity after compression is very high and the core region shrinks quickly due to rapid entrainment of cold gases. Whereas, for a creviced piston head design, gas velocity after compression is significantly lower and the core region remains unaffected for a long duration. As a consequence, for the flat piston, adiabatic core assumption can significantly overpredict the maximum temperature after the end of compression. For the creviced piston, the adiabatic core assumption is found to be valid even up to 100 ms after compression. This work therefore experimentally and numerically substantiates the importance of piston head design for achieving a homogeneous core region inside a rapid compression machine. (author)

  4. Evidence-Based Compression

    PubMed Central

    Morris, Rhys J.; Woodcock, John P.

    2004-01-01

    Objective: To summarize the currently published scientific evidence for the venous flow effects of mechanical devices, particularly intermittent pneumatic compression, and the relation to prevention of deep vein thrombosis (DVT). Summary Background Data: While intermittent pneumatic compression is an established method of DVT prophylaxis, the variety of systems that are available can use very different compression techniques and sequences. In order for appropriate choices to be made to provide the optimum protection for patients, the general performance of systems, and physiological effects of particular properties, must be analyzed objectively. Methods: Medline was searched from 1970 to 2002, and all relevant papers were searched for further appropriate references. Papers were selected for inclusion when they addressed specifically the questions posed in this review. Results: All the major types of intermittent compression systems are successful in emptying deep veins of the lower limb and preventing stasis in a variety of subject groups. Compression stockings appear to function more by preventing distension of veins. Rapid inflation, high pressures, and graded sequential intermittent compression systems will have particular augmentation profiles, but there is no evidence that such features improve the prophylactic ability of the system. Conclusions: The most important factors in selecting a mechanical prophylactic system, particularly during and after surgery, are patient compliance and the appropriateness of the site of compression. There is no evidence that the peak venous velocity produced by a system is a valid measure of medical performance. PMID:14745323

  5. Vascular compression syndromes.

    PubMed

    Czihal, Michael; Banafsche, Ramin; Hoffmann, Ulrich; Koeppel, Thomas

    2015-11-01

    Dealing with vascular compression syndromes is one of the most challenging tasks in Vascular Medicine practice. This heterogeneous group of disorders is characterised by external compression of primarily healthy arteries and/or veins as well as accompanying nerval structures, carrying the risk of subsequent structural vessel wall and nerve damage. Vascular compression syndromes may severely impair health-related quality of life in affected individuals who are typically young and otherwise healthy. The diagnostic approach has not been standardised for any of the vascular compression syndromes. Moreover, some degree of positional external compression of blood vessels such as the subclavian and popliteal vessels or the celiac trunk can be found in a significant proportion of healthy individuals. This implies important difficulties in differentiating physiological from pathological findings of clinical examination and diagnostic imaging with provocative manoeuvres. The level of evidence on which treatment decisions regarding surgical decompression with or without revascularisation can be relied on is generally poor, mostly coming from retrospective single centre studies. Proper patient selection is critical in order to avoid overtreatment in patients without a clear association between vascular compression and clinical symptoms. With a focus on the thoracic outlet-syndrome, the median arcuate ligament syndrome and the popliteal entrapment syndrome, the present article gives a selective literature review on compression syndromes from an interdisciplinary vascular point of view. PMID:26515219

  6. Radio frequency pulse compression

    SciTech Connect

    Farkas, Z.D.

    1988-12-01

    High gradients require peak powers. One possible way to generate high peak powers is to generate a relatively long pulse at a relatively low power and compress it into a shorter pulse with higher peak power. It is possible to compress before dc to rf conversion as is done for the relativistic klystron or after dc to rf conversion as is done with SLED. In this note only radio frequency pulse compression (RFPC) is considered. Three methods of RFPC will be discussed: SLED, BEC, and REC. 3 refs., 8 figs., 1 tab.

  7. Boson core compressibility

    NASA Astrophysics Data System (ADS)

    Khorramzadeh, Y.; Lin, Fei; Scarola, V. W.

    2012-04-01

    Strongly interacting atoms trapped in optical lattices can be used to explore phase diagrams of Hubbard models. Spatial inhomogeneity due to trapping typically obscures distinguishing observables. We propose that measures using boson double occupancy avoid trapping effects to reveal two key correlation functions. We define a boson core compressibility and core superfluid stiffness in terms of double occupancy. We use quantum Monte Carlo on the Bose-Hubbard model to empirically show that these quantities intrinsically eliminate edge effects to reveal correlations near the trap center. The boson core compressibility offers a generally applicable tool that can be used to experimentally map out phase transitions between compressible and incompressible states.

  8. Compressive Optical Image Encryption

    NASA Astrophysics Data System (ADS)

    Li, Jun; Sheng Li, Jiao; Yang Pan, Yang; Li, Rong

    2015-05-01

    An optical image encryption technique based on compressive sensing using fully optical means has been proposed. An object image is first encrypted to a white-sense stationary noise pattern using a double random phase encoding (DRPE) method in a Mach-Zehnder interferometer. Then, the encrypted image is highly compressed to a signal using single-pixel compressive holographic imaging in the optical domain. At the receiving terminal, the encrypted image is reconstructed well via compressive sensing theory, and the original image can be decrypted with three reconstructed holograms and the correct keys. The numerical simulations show that the method is effective and suitable for optical image security transmission in future all-optical networks because of the ability of completely optical implementation and substantially smaller hologram data volume.

  9. Image Data Compression

    NASA Astrophysics Data System (ADS)

    Kunt, Murat

    1988-03-01

    Image data compression is one of the oldest but still very active area of research in image processing. The digital representation of an image requires a very large number of bits. The goal of image data compression is to reduce this number, as much as possible, and reconstruct a faithful duplicate of the original picture. Early efforts in image coding, solely guided by information theory, led to a plethora of methods. The compression ratio reached a plateau around 10:1 a couple of years ago. Recent progress in the study of the brain mechanism of vision and scene analysis has opened new vistas in picture coding. Directional sensitivity of the neurones in the visual pathway combined with the separate processing of contours and textures has led to a new class of coding methods capable of achieving compression ratios as high as 100:1.

  10. Compressible Astrophysics Simulation Code

    Energy Science and Technology Software Center (ESTSC)

    2007-07-18

    This is an astrophysics simulation code involving a radiation diffusion module developed at LLNL coupled to compressible hydrodynamics and adaptive mesh infrastructure developed at LBNL. One intended application is to neutrino diffusion in core collapse supernovae.

  11. Vertebral Compression Fractures

    MedlinePLUS

    ... OI: Information on Vertebral Compression Fractures 804 W. Diamond Ave., Ste. 210 Gaithersburg, MD 20878 (800) 981- ... osteogenesis imperfecta contact : Osteogenesis Imperfecta Foundation 804 W. Diamond Avenue, Suite 210, Gaithersburg, MD 20878 Tel: 800- ...

  12. Compressive laser ranging.

    PubMed

    Babbitt, Wm Randall; Barber, Zeb W; Renner, Christoffer

    2011-12-15

    Compressive sampling has been previously proposed as a technique for sampling radar returns and determining sparse range profiles with a reduced number of measurements compared to conventional techniques. By employing modulation on both transmission and reception, compressive sensing in ranging is extended to the direct measurement of range profiles without intermediate measurement of the return waveform. This compressive ranging approach enables the use of pseudorandom binary transmit waveforms and return modulation, along with low-bandwidth optical detectors to yield high-resolution ranging information. A proof-of-concept experiment is presented. With currently available compact, off-the-shelf electronics and photonics, such as high data rate binary pattern generators and high-bandwidth digital optical modulators, compressive laser ranging can readily achieve subcentimeter resolution in a compact, lightweight package. PMID:22179886

  13. The Compressibility Bubble

    NASA Technical Reports Server (NTRS)

    Stack, John

    1935-01-01

    Simultaneous air-flow photographs and pressure-distribution measurements have been made of the NACA 4412 airfoil at high speeds in order to determine the physical nature of the compressibility bubble. The flow photographs were obtained by the Schlieren method and the pressures were simultaneously measured for 54 stations on the 5-inch-chord wing by means of a multiple-tube photographic manometer. Pressure-measurement results and typical Schlieren photographs are presented. The general nature of the phenomenon called the "compressibility bubble" is shown by these experiments. The source of the increased drag is the compression shock that occurs, the excess drag being due to the conversion of a considerable amount of the air-stream kinetic energy into heat at the compression shock.

  14. Compressive Optical Image Encryption

    PubMed Central

    Li, Jun; Sheng Li, Jiao; Yang Pan, Yang; Li, Rong

    2015-01-01

    An optical image encryption technique based on compressive sensing using fully optical means has been proposed. An object image is first encrypted to a white-sense stationary noise pattern using a double random phase encoding (DRPE) method in a Mach-Zehnder interferometer. Then, the encrypted image is highly compressed to a signal using single-pixel compressive holographic imaging in the optical domain. At the receiving terminal, the encrypted image is reconstructed well via compressive sensing theory, and the original image can be decrypted with three reconstructed holograms and the correct keys. The numerical simulations show that the method is effective and suitable for optical image security transmission in future all-optical networks because of the ability of completely optical implementation and substantially smaller hologram data volume. PMID:25992946

  15. Compressive optical image encryption.

    PubMed

    Li, Jun; Sheng Li, Jiao; Yang Pan, Yang; Li, Rong

    2015-01-01

    An optical image encryption technique based on compressive sensing using fully optical means has been proposed. An object image is first encrypted to a white-sense stationary noise pattern using a double random phase encoding (DRPE) method in a Mach-Zehnder interferometer. Then, the encrypted image is highly compressed to a signal using single-pixel compressive holographic imaging in the optical domain. At the receiving terminal, the encrypted image is reconstructed well via compressive sensing theory, and the original image can be decrypted with three reconstructed holograms and the correct keys. The numerical simulations show that the method is effective and suitable for optical image security transmission in future all-optical networks because of the ability of completely optical implementation and substantially smaller hologram data volume. PMID:25992946

  16. Biaxial compression test technique

    NASA Technical Reports Server (NTRS)

    Hansard, E. T.

    1975-01-01

    Fixture and technique have been developed for predicting behavior of stiffened skin panels under biaxial compressive loading. Tester can load test panel independently in longitudinal and transverse directions. Data can also be obtained in combined mode.

  17. Compressibility Effects in Aeronautical Engineering

    NASA Technical Reports Server (NTRS)

    Stack, John

    1941-01-01

    Compressible-flow research, while a relatively new field in aeronautics, is very old, dating back almost to the development of the first firearm. Over the last hundred years, researches have been conducted in the ballistics field, but these results have been of practically no use in aeronautical engineering because the phenomena that have been studied have been the more or less steady supersonic condition of flow. Some work that has been done in connection with steam turbines, particularly nozzle studies, has been of value, In general, however, understanding of compressible-flow phenomena has been very incomplete and permitted no real basis for the solution of aeronautical engineering problems in which.the flow is likely to be unsteady because regions of both subsonic and supersonic speeds may occur. In the early phases of the development of the airplane, speeds were so low that the effects of compressibility could be justifiably ignored. During the last war and immediately after, however, propellers exhibited losses in efficiency as the tip speeds approached the speed of sound, and the first experiments of an aeronautical nature were therefore conducted with propellers. Results of these experiments indicated serious losses of efficiency, but aeronautical engineers were not seriously concerned at the time became it was generally possible. to design propellers with quite low tip. speeds. With the development of new engines having increased power and rotational speeds, however, the problems became of increasing importance.

  18. Saugus Iron Works Forge

    USGS Multimedia Gallery

    The Saugus Iron Works forge, which used a large hammer to compress the iron. Forging strenghened the iron, which, right out of the blast furnace, was brittle. The Saugus River, which powered the forge, can be seen in the background....

  19. Adult Learners' Week in Australia.

    ERIC Educational Resources Information Center

    Cross, John

    2002-01-01

    Promotional materials and activities for Australia's Adult Learners Week, which are shaped by a variety of stakeholders , include media strategies and a website. Activities are evaluated using a market research company and website and telephone hotline statistics. (SK)

  20. Image compression technique

    DOEpatents

    Fu, C.Y.; Petrich, L.I.

    1997-03-25

    An image is compressed by identifying edge pixels of the image; creating a filled edge array of pixels each of the pixels in the filled edge array which corresponds to an edge pixel having a value equal to the value of a pixel of the image array selected in response to the edge pixel, and each of the pixels in the filled edge array which does not correspond to an edge pixel having a value which is a weighted average of the values of surrounding pixels in the filled edge array which do correspond to edge pixels; and subtracting the filled edge array from the image array to create a difference array. The edge file and the difference array are then separately compressed and transmitted or stored. The original image is later reconstructed by creating a preliminary array in response to the received edge file, and adding the preliminary array to the received difference array. Filling is accomplished by solving Laplace`s equation using a multi-grid technique. Contour and difference file coding techniques also are described. The techniques can be used in a method for processing a plurality of images by selecting a respective compression approach for each image, compressing each of the images according to the compression approach selected, and transmitting each of the images as compressed, in correspondence with an indication of the approach selected for the image. 16 figs.

  1. Image compression technique

    DOEpatents

    Fu, Chi-Yung; Petrich, Loren I.

    1997-01-01

    An image is compressed by identifying edge pixels of the image; creating a filled edge array of pixels each of the pixels in the filled edge array which corresponds to an edge pixel having a value equal to the value of a pixel of the image array selected in response to the edge pixel, and each of the pixels in the filled edge array which does not correspond to an edge pixel having a value which is a weighted average of the values of surrounding pixels in the filled edge array which do correspond to edge pixels; and subtracting the filled edge array from the image array to create a difference array. The edge file and the difference array are then separately compressed and transmitted or stored. The original image is later reconstructed by creating a preliminary array in response to the received edge file, and adding the preliminary array to the received difference array. Filling is accomplished by solving Laplace's equation using a multi-grid technique. Contour and difference file coding techniques also are described. The techniques can be used in a method for processing a plurality of images by selecting a respective compression approach for each image, compressing each of the images according to the compression approach selected, and transmitting each of the images as compressed, in correspondence with an indication of the approach selected for the image.

  2. Alternative Compression Garments

    NASA Technical Reports Server (NTRS)

    Stenger, M. B.; Lee, S. M. C.; Ribeiro, L. C.; Brown, A. K.; Westby, C. M.; Platts, S. H.

    2011-01-01

    Orthostatic intolerance after spaceflight is still an issue for astronauts as no in-flight countermeasure has been 100% effective. Future anti-gravity suits (AGS) may be similar to the Shuttle era inflatable AGS or may be a mechanical compression device like the Russian Kentavr. We have evaluated the above garments as well as elastic, gradient compression garments of varying magnitude and determined that breast-high elastic compression garments may be a suitable replacement to the current AGS. This new garment should be more comfortable than the AGS, easy to don and doff, and as effective a countermeasure to orthostatic intolerance. Furthermore, these new compression garments could be worn for several days after space flight as necessary if symptoms persisted. We conducted two studies to evaluate elastic, gradient compression garments. The purpose of these studies was to evaluate the comfort and efficacy of an alternative compression garment (ACG) immediately after actual space flight and 6 degree head-down tilt bed rest as a model of space flight, and to determine if they would impact recovery if worn for up to three days after bed rest.

  3. Micromechanics of composite laminate compression failures

    NASA Technical Reports Server (NTRS)

    Guynn, E. Gail; Bradley, Walter L.

    1988-01-01

    The purpose of this annual progress report is to summarize the work effort and results accomplished from July 1987 through July 1988 on NASA Research Grant NAG1-659 entitled Micromechanics of Composite Laminate Compressive Failure. The report contains: (1) the objective of the proposed research, (2) the summary of accomplishments, (3) a more extensive review of compression literature, (4) the planned material (and corresponding properties) received to date, (5) the results for three possible specimen geometries, experimental procedures planned, and current status of the experiments, and (6) the work planned for the next contract year.

  4. Lossless compression of instrumentation data. Final report

    SciTech Connect

    Stearns, S.D.

    1995-11-01

    This is our final report on Sandia National Laboratories Laboratory- Directed Research and Development (LDRD) project 3517.070. Its purpose has been to investigate lossless compression of digital waveform and image data, particularly the types of instrumentation data generated and processed at Sandia Labs. The three-year project period ran from October 1992 through September 1995. This report begins with a descriptive overview of data compression, with and without loss, followed by a summary of the activities on the Sandia project, including research at several universities and the development of waveform compression software. Persons who participated in the project are also listed. The next part of the report contains a general discussion of the principles of lossless compression. Two basic compression stages, decorrelation and entropy coding, are described and discussed. An example of seismic data compression is included. Finally, there is a bibliography of published research. Taken together, the published papers contain the details of most of the work and accomplishments on the project. This final report is primarily an overview, without the technical details and results found in the publications listed in the bibliography.

  5. Compression-sensitive magnetic resonance elastography

    NASA Astrophysics Data System (ADS)

    Hirsch, Sebastian; Beyer, Frauke; Guo, Jing; Papazoglou, Sebastian; Tzschaetzsch, Heiko; Braun, Juergen; Sack, Ingolf

    2013-08-01

    Magnetic resonance elastography (MRE) quantifies the shear modulus of biological tissue to detect disease. Complementary to the shear elastic properties of tissue, the compression modulus may be a clinically useful biomarker because it is sensitive to tissue pressure and poromechanical interactions. In this work, we analyze the capability of MRE to measure volumetric strain and the dynamic bulk modulus (P-wave modulus) at a harmonic drive frequency commonly used in shear-wave-based MRE. Gel phantoms with various densities were created by introducing CO2-filled cavities to establish a compressible effective medium. The dependence of the effective medium's bulk modulus on phantom density was investigated via static compression tests, which confirmed theoretical predictions. The P-wave modulus of three compressible phantoms was calculated from volumetric strain measured by 3D wave-field MRE at 50 Hz drive frequency. The results demonstrate the MRE-derived volumetric strain and P-wave modulus to be sensitive to the compression properties of effective media. Since the reconstruction of the P-wave modulus requires third-order derivatives, noise remains critical, and P-wave moduli are systematically underestimated. Focusing on relative changes in the effective bulk modulus of tissue, compression-sensitive MRE may be useful for the noninvasive detection of diseases involving pathological pressure alterations such as hepatic hypertension or hydrocephalus.

  6. Pregnancy Calendar: A Week-by-Week Guide

    MedlinePLUS

    ... and your baby healthy. A Word About Due Dates and Trimesters After you announce your pregnancy, the first question you'll probably be asked is "When are you due?" At your first prenatal visit, your health care provider will ... determine an expected delivery date (EDD). Your EDD is 40 weeks from the ...

  7. Transverse Compression of Tendons.

    PubMed

    Samuel Salisbury, S T; Paul Buckley, C; Zavatsky, Amy B

    2016-04-01

    A study was made of the deformation of tendons when compressed transverse to the fiber-aligned axis. Bovine digital extensor tendons were compression tested between flat rigid plates. The methods included: in situ image-based measurement of tendon cross-sectional shapes, after preconditioning but immediately prior to testing; multiple constant-load creep/recovery tests applied to each tendon at increasing loads; and measurements of the resulting tendon displacements in both transverse directions. In these tests, friction resisted axial stretch of the tendon during compression, giving approximately plane-strain conditions. This, together with the assumption of a form of anisotropic hyperelastic constitutive model proposed previously for tendon, justified modeling the isochronal response of tendon as that of an isotropic, slightly compressible, neo-Hookean solid. Inverse analysis, using finite-element (FE) simulations of the experiments and 10?s isochronal creep displacement data, gave values for Young's modulus and Poisson's ratio of this solid of 0.31?MPa and 0.49, respectively, for an idealized tendon shape and averaged data for all the tendons and E?=?0.14 and 0.10?MPa for two specific tendons using their actual measured geometry. The compression load versus displacement curves, as measured and as simulated, showed varying degrees of stiffening with increasing load. This can be attributed mostly to geometrical changes in tendon cross section under load, varying according to the initial 3D shape of the tendon. PMID:26833218

  8. Compressibility variations of JPEG2000 compressed computed tomography.

    PubMed

    Pambrun, Jean-François; Noumeir, Rita

    2013-01-01

    Compression is increasingly used in medical applications to enable efficient and universally accessible electronic health records. However, lossy compression introduces artifacts that can alter diagnostic accuracy, interfere with image processing algorithms and cause liability issues in cases of diagnostic errors. Compression guidelines were introduced to mitigate these issues and foster the use of modern compression algorithms with diagnostic imaging. However, these guidelines are usually defined as maximum compression ratios for each imaging protocol and do not take compressibility variations due to image content into account. In this paper we have evaluated the compressibility of thousands of computed tomography slices of an anthropomorphic thoracic phantom acquired with different parameters. We have shown that exposure, slice thickness and reconstruction filters have a significant impact on compressibility suggesting that guidelines based solely on compression ratios may be inadequate. PMID:24110452

  9. Image compression for dermatology

    NASA Astrophysics Data System (ADS)

    Cookson, John P.; Sneiderman, Charles; Colaianni, Joseph; Hood, Antoinette F.

    1990-07-01

    Color 35mm photographic slides are commonly used in dermatology for education, and patient records. An electronic storage and retrieval system for digitized slide images may offer some advantages such as preservation and random access. We have integrated a system based on a personal computer (PC) for digital imaging of 35mm slides that depict dermatologic conditions. Such systems require significant resources to accommodate the large image files involved. Methods to reduce storage requirements and access time through image compression are therefore of interest. This paper contains an evaluation of one such compression method that uses the Hadamard transform implemented on a PC-resident graphics processor. Image quality is assessed by determining the effect of compression on the performance of an image feature recognition task.

  10. Compressible Flow Toolbox

    NASA Technical Reports Server (NTRS)

    Melcher, Kevin J.

    2006-01-01

    The Compressible Flow Toolbox is primarily a MATLAB-language implementation of a set of algorithms that solve approximately 280 linear and nonlinear classical equations for compressible flow. The toolbox is useful for analysis of one-dimensional steady flow with either constant entropy, friction, heat transfer, or Mach number greater than 1. The toolbox also contains algorithms for comparing and validating the equation-solving algorithms against solutions previously published in open literature. The classical equations solved by the Compressible Flow Toolbox are as follows: The isentropic-flow equations, The Fanno flow equations (pertaining to flow of an ideal gas in a pipe with friction), The Rayleigh flow equations (pertaining to frictionless flow of an ideal gas, with heat transfer, in a pipe of constant cross section), The normal-shock equations, The oblique-shock equations, and The expansion equations.

  11. Isentropic Compression of Argon

    SciTech Connect

    H. Oona; J.C. Solem; L.R. Veeser, C.A. Ekdahl; P.J. Rodriquez; S.M. Younger; W. Lewis; W.D. Turley

    1997-08-01

    We are studying the transition of argon from an insulator to a conductor by compressing the frozen gas isentropically to pressures at which neighboring atomic orbitals overlap sufficiently to allow some electron motion between atoms. Argon and the other rare gases have closed electron shells and therefore remain montomic, even when they solidify. Their simple structure makes it likely that any measured change in conductivity is due to changes in the atomic structure, not in molecular configuration. As the crystal is compressed the band gap closes, allowing increased conductivity. We have begun research to determine the conductivity at high pressures, and it is our intention to determine the compression at which the crystal becomes a metal.

  12. Envera Variable Compression Ratio Engine

    SciTech Connect

    Charles Mendler

    2011-03-15

    Aggressive engine downsizing, variable compression ratio and use of the Atkinson cycle are being combined to improve fuel economy by up to 40 percent relative to port fuel injected gasoline engines, while maintaining full engine power. Approach Engine downsizing is viewed by US and foreign automobile manufacturers as one of the best options for improving fuel economy. While this strategy has already demonstrated a degree of success, downsizing and fuel economy gains are currently limited. With new variable compression ratio technology however, the degree of engine downsizing and fuel economy improvement can be greatly increased. A small variable compression ratio (VCR) engine has the potential to return significantly higher vehicle fuel economy while also providing high power. Affordability and potential for near term commercialization are key attributes of the Envera VCR engine. VCR Technology To meet torque and power requirements, a smaller engine needs to do more work per stroke. This is typically accomplished by boosting the incoming charge with either a turbo or supercharger so that more energy is present in the cylinder per stroke to do the work. With current production engines the degree of engine boosting (which correlates to downsizing) is limited by detonation (combustion knock) at high boost levels. Additionally, the turbo or supercharger needs to be responsive and efficient while providing the needed boost. VCR technology eliminates the limitation of engine knock at high load levels by reducing compression ratio to {approx}9:1 (or whatever level is appropriate) when high boost pressures are needed. By reducing the compression ratio during high load demand periods there is increased volume in the cylinder at top dead center (TDC) which allows more charge (or energy) to be present in the cylinder without increasing the peak pressure. Cylinder pressure is thus kept below the level at which the engine would begin to knock. When loads on the engine are low the compression ratio can be raised (to as much as 18:1) providing high engine efficiency. It is important to recognize that for a well designed VCR engine cylinder pressure does not need to be higher than found in current production turbocharged engines. As such, there is no need for a stronger crankcase, bearings and other load bearing parts within the VCR engine. The Envera VCR mechanism uses an eccentric carrier approach to adjust engine compression ratio. The crankshaft main bearings are mounted in this eccentric carrier or 'crankshaft cradle' and pivoting the eccentric carrier 30 degrees adjusts compression ratio from 9:1 to 18:1. The eccentric carrier is made up of a casting that provides rigid support for the main bearings, and removable upper bearing caps. Oil feed to the main bearings transits through the bearing cap fastener sockets. The eccentric carrier design was chosen for its low cost and rigid support of the main bearings. A control shaft and connecting links are used to pivot the eccentric carrier. The control shaft mechanism features compression ratio lock-up at minimum and maximum compression ratio settings. The control shaft method of pivoting the eccentric carrier was selected due to its lock-up capability. The control shaft can be rotated by a hydraulic actuator or an electric motor. The engine shown in Figures 3 and 4 has a hydraulic actuator that was developed under the current program. In-line 4-cylinder engines are significantly less expensive than V engines because an entire cylinder head can be eliminated. The cost savings from eliminating cylinders and an entire cylinder head will notably offset the added cost of the VCR and supercharging. Replacing V6 and V8 engines with in-line VCR 4-cylinder engines will provide high fuel economy at low cost. Numerous enabling technologies exist which have the potential to increase engine efficiency. The greatest efficiency gains are realized when the right combination of advanced and new technologies are packaged together to provide the greatest gains at the least cost. Aggressive engine downsizing with variable compression ratio and use of the extended Atkinson cycle can provide large fuel economy gains that are exceptionally cost effective. Analysis indicates that a 2.2L supercharged Envera VCR engine can match the torque of a larger V8 engine at 2000 rpm. The VCR engine's high torque value at low engine speed is beneficial for maintaining the driving feel and responsiveness of the larger V8 engine. The Envera VCR engine will attain high efficiency at {approx}100 Nm primarily due to the combination of engine down-sizing and use of the Atkinson cycle. Qualitatively the fuel economy gain realized from down-sizing from a V8 to an Atkinson-cycle I-4 is about twice as large as the benefits from down-sizing from a V8 to a Turbo V6 when evaluated at 100 Nm 2000 rpm.

  13. Orbiting dynamic compression laboratory

    NASA Technical Reports Server (NTRS)

    Ahrens, T. J.; Vreeland, T., Jr.; Kasiraj, P.; Frisch, B.

    1984-01-01

    In order to examine the feasibility of carrying out dynamic compression experiments on a space station, the possibility of using explosive gun launchers is studied. The question of whether powders of a refractory metal (molybdenum) and a metallic glass could be well considered by dynamic compression is examined. In both cases extremely good bonds are obtained between grains of metal and metallic glass at 180 and 80 kb, respectively. When the oxide surface is reduced and the dynamic consolidation is carried out in vacuum, in the case of molybdenum, tensile tests of the recovered samples demonstrated beneficial ultimate tensile strengths.

  14. Isentropic compression of argon

    SciTech Connect

    Veeser, L.R.; Ekdahl, C.A.; Oona, H.

    1997-06-01

    The compression was done in an MC-1 flux compression (explosive) generator, in order to study the transition from an insulator to a conductor. Since conductivity signals were observed in all the experiments (except when the probe is removed), both the Teflon and the argon are becoming conductive. The conductivity could not be determined (Teflon insulation properties unknown), but it could be bounded as being {sigma}=1/{rho}{le}8({Omega}cm){sub -1}, because when the Teflon breaks down, the dielectric constant is reduced. The Teflon insulator problem remains, and other ways to better insulate the probe or to measure the conductivity without a probe is being sought.

  15. Portuguese Special Course: 12 Weeks.

    ERIC Educational Resources Information Center

    Defense Language Inst., Washington, DC.

    This 12-week course in beginning Portuguese comprises four volumes of student text (Lessons 1-55) and a fifth volume of Portuguese-English/English-Portuguese vocabulary. Lesson materials consist of basic dialogs with English translation, recombination dialogs, readings and comprehension questions, oral exercises, and in later units, additional…

  16. 76 FR 58711 - National Farm Safety and Health Week, 2011

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-21

    ... the two hundred and thirty-sixth. (Presidential Sig.) [FR Doc. 2011-24445 Filed 9-20-11; 11:15 am... dream-- passing on proud traditions of hard work and commitment to their children. This week,...

  17. Compressive strength of continuous fiber unidirectional composites

    NASA Astrophysics Data System (ADS)

    Thompson, Ronald H.

    Dow and Rosen's work in 1965 formed an intellectual framework for compressive strength of unidirectional composites. Compressive strength was explained in terms of micro-buckling, in which filaments are beams on an elastic foundation. They made simplifying assumptions, with a two dimensional idealization and linearized material properties. This study builds on their model, recognizing that the shear mode of instability drives unidirectional compressive strength. As a necessary corollary, the predictive methods developed in this study emphasize correct representation of composite shear stiffness. Non-linear effects related to matrix material properties, fiber misalignment, three dimensional representation, and thermal prestrains are taken into account. Four work streams comprise this study: first, development of a closed form analytical model; second, empirical methods development and model validation; third, creation and validation of a unit cell finite element model; and fourth, a patent application that leverages knowledge gained from the first three work streams. The analytical model characterizes the non-linearity of the matrix both with respect to shear and compressive loading. This improvement on existing analyses clearly shows why fiber modulus affects composite shear instability. Accounting for fiber misalignment in the model and experimental characterization of the fiber misalignment continuum are important contributions of this study. A simple method of compressive strength measurement of a small diameter monofilament glass-resin composite is developed. Sample definition and preparation are original, and necessary technologies are easily assessable to other researchers in this field. This study shows that glass fiber composites have the potential for high compressive strength. This potential is reached with excellent fiber alignment and suitable matrix characteristics, and results are consistent with model predictions. The unit cell three dimensional finite element model introduces a boundary condition that only allows compressive and shear deformation, thus recognizing the actual deformation mechanism of a compressed unidirectional composite. A new approach for representing the resin matrix is employed, giving improved correlation to empirical measurements noted in the literature. A method of accounting for realistic composite imperfections is introduced. The patent application work was fed by results from the first three areas. A new engineering structure is created in which buckling is beneficial. Post buckled behavior favorably affects other structural components in an overload situation. The first three work streams form a coherent unit and are mutually supportive. The analytical model predictions are corroborated by the experimental measurements. Finite element model predictions are consistent with the analytical model predictions.

  18. Structure and Properties of Silica Glass Densified in Cold Compression and Hot Compression

    PubMed Central

    Guerette, Michael; Ackerson, Michael R.; Thomas, Jay; Yuan, Fenglin; Bruce Watson, E.; Walker, David; Huang, Liping

    2015-01-01

    Silica glass has been shown in numerous studies to possess significant capacity for permanent densification under pressure at different temperatures to form high density amorphous (HDA) silica. However, it is unknown to what extent the processes leading to irreversible densification of silica glass in cold-compression at room temperature and in hot-compression (e.g., near glass transition temperature) are common in nature. In this work, a hot-compression technique was used to quench silica glass from high temperature (1100?°C) and high pressure (up to 8?GPa) conditions, which leads to density increase of ~25% and Young’s modulus increase of ~71% relative to that of pristine silica glass at ambient conditions. Our experiments and molecular dynamics (MD) simulations provide solid evidences that the intermediate-range order of the hot-compressed HDA silica is distinct from that of the counterpart cold-compressed at room temperature. This explains the much higher thermal and mechanical stability of the former than the latter upon heating and compression as revealed in our in-situ Brillouin light scattering (BLS) experiments. Our studies demonstrate the limitation of the resulting density as a structural indicator of polyamorphism, and point out the importance of temperature during compression in order to fundamentally understand HDA silica. PMID:26469314

  19. Structure and Properties of Silica Glass Densified in Cold Compression and Hot Compression

    NASA Astrophysics Data System (ADS)

    Guerette, Michael; Ackerson, Michael R.; Thomas, Jay; Yuan, Fenglin; Bruce Watson, E.; Walker, David; Huang, Liping

    2015-10-01

    Silica glass has been shown in numerous studies to possess significant capacity for permanent densification under pressure at different temperatures to form high density amorphous (HDA) silica. However, it is unknown to what extent the processes leading to irreversible densification of silica glass in cold-compression at room temperature and in hot-compression (e.g., near glass transition temperature) are common in nature. In this work, a hot-compression technique was used to quench silica glass from high temperature (1100 °C) and high pressure (up to 8 GPa) conditions, which leads to density increase of ~25% and Young’s modulus increase of ~71% relative to that of pristine silica glass at ambient conditions. Our experiments and molecular dynamics (MD) simulations provide solid evidences that the intermediate-range order of the hot-compressed HDA silica is distinct from that of the counterpart cold-compressed at room temperature. This explains the much higher thermal and mechanical stability of the former than the latter upon heating and compression as revealed in our in-situ Brillouin light scattering (BLS) experiments. Our studies demonstrate the limitation of the resulting density as a structural indicator of polyamorphism, and point out the importance of temperature during compression in order to fundamentally understand HDA silica.

  20. Watermark Compression in Medical Image Watermarking Using Lempel-Ziv-Welch (LZW) Lossless Compression Technique.

    PubMed

    Badshah, Gran; Liew, Siau-Chuin; Zain, Jasni Mohd; Ali, Mushtaq

    2016-04-01

    In teleradiology, image contents may be altered due to noisy communication channels and hacker manipulation. Medical image data is very sensitive and can not tolerate any illegal change. Illegally changed image-based analysis could result in wrong medical decision. Digital watermarking technique can be used to authenticate images and detect as well as recover illegal changes made to teleradiology images. Watermarking of medical images with heavy payload watermarks causes image perceptual degradation. The image perceptual degradation directly affects medical diagnosis. To maintain the image perceptual and diagnostic qualities standard during watermarking, the watermark should be lossless compressed. This paper focuses on watermarking of ultrasound medical images with Lempel-Ziv-Welch (LZW) lossless-compressed watermarks. The watermark lossless compression reduces watermark payload without data loss. In this research work, watermark is the combination of defined region of interest (ROI) and image watermarking secret key. The performance of the LZW compression technique was compared with other conventional compression methods based on compression ratio. LZW was found better and used for watermark lossless compression in ultrasound medical images watermarking. Tabulated results show the watermark bits reduction, image watermarking with effective tamper detection and lossless recovery. PMID:26429361

  1. Detail of interior of compressed air chamber showing top of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of interior of compressed air chamber showing top of working chamber and tie rods that strengthen the outer shell plates of the compression chamber. - Sub Marine Explorer, Located along the beach of Isla San Telmo, Pearl Islands, Isla San Telmo, Former Panama Canal Zone, CZ

  2. Low-complexity image compression with scalable quality control

    NASA Astrophysics Data System (ADS)

    Pillman, Bruce H.; Napoli, Michael E.

    2014-06-01

    The Rice algorithm is a standard for numerically lossless image compression, especially for space applications, as described by the Consultative Committee for Space Data Systems. It is remarkably simple and adaptable and delivers effective compression for a wide range of signals. The present work investigates an extension of the standard Rice algorithm to support lossy compression, referred to as Enhanced Rice, or ERICE. The extended system allows compression to scale gracefully from numerically lossless to visually lossy and is only slightly more complex than the numerically lossless system.

  3. Comparative analysis of infrared images degraded by lossy compression techniques

    NASA Astrophysics Data System (ADS)

    Toussaint, W. A.; Weber, Reed A.

    2015-09-01

    This work addresses image degradation introduced by lossy compression techniques and the effects of such degradation on signal detection statistics for applications in fast-framing (<100 Hz) IR image analysis. As future space systems make use of increasingly higher pixel count IR focal plane arrays, data generation rates are anticipated to become too copious for continuous download. The prevailing solution to this issue has been to compress image data prior to downlink. While this solution is application independent for lossless compression, the expected benefits of lossy compression, including higher compression ratio, necessitate several application specific trades in order to characterize preservation of critical information within the data. Current analyses via standard statistical image processing techniques following tunably lossy compression algorithms (JPEG2000, JPEG-LS) allow for detection statistics nearly identical to analyses following standard lossless compression techniques, such as Rice and PNG, even at degradation levels offering a greater than twofold increase in compression ratio. Ongoing efforts focus on repeating the analysis for other tunably lossy compression techniques while also assessing the relative computational burden of each algorithm. Current results suggest that lossy compression techniques can preserve critical information in fast-framing IR data while either significantly reducing downlink bandwidth requirements or significantly increasing the usable focal plane array window size.

  4. Improved compression molding process

    NASA Technical Reports Server (NTRS)

    Heier, W. C.

    1967-01-01

    Modified compression molding process produces plastic molding compounds that are strong, homogeneous, free of residual stresses, and have improved ablative characteristics. The conventional method is modified by applying a vacuum to the mold during the molding cycle, using a volatile sink, and exercising precise control of the mold closure limits.

  5. Compress Your Files

    ERIC Educational Resources Information Center

    Branzburg, Jeffrey

    2005-01-01

    File compression enables data to be squeezed together, greatly reducing file size. Why would someone want to do this? Reducing file size enables the sending and receiving of files over the Internet more quickly, the ability to store more files on the hard drive, and the ability pack many related files into one archive (for example, all files…

  6. The Compressed Video Experience.

    ERIC Educational Resources Information Center

    Weber, John

    In the fall semester 1995, Southern Arkansas University- Magnolia (SAU-M) began a two semester trial delivering college classes via a compressed video link between SAU-M and its sister school Southern Arkansas University Tech (SAU-T) in Camden. As soon as the University began broadcasting and receiving classes, it was discovered that using the…

  7. Compressed gas handbook

    NASA Technical Reports Server (NTRS)

    Cota, R. A.; Kunkle, J. S.; Wilson, S. D.

    1971-01-01

    Handbook includes thermodynamic and related fluid flow data required to analyze high pressure compressible and incompressible fluid systems. Some theory and applications include thermodynamic fundamentals, gas behavior, adiabatic and isentropic flow, shock waves, flow measurement, and adiabatic and isothermal friction flow in pipes.

  8. Compress Your Files

    ERIC Educational Resources Information Center

    Branzburg, Jeffrey

    2005-01-01

    File compression enables data to be squeezed together, greatly reducing file size. Why would someone want to do this? Reducing file size enables the sending and receiving of files over the Internet more quickly, the ability to store more files on the hard drive, and the ability pack many related files into one archive (for example, all files…

  9. Focus on Compression Stockings

    MedlinePLUS

    ... soap. Do not use Woolite™ detergent. Use warm water and wash by hand or in the gentle cycle in the washing machine. After rinsing the compression stocking completely, remove excess water by rolling it in a ... the dryer on the deli- cate cycle at a cool temperature. It may be convenient ...

  10. Compression: Rent or own

    SciTech Connect

    Cahill, C.

    1997-07-01

    Historically, the decision to purchase or rent compression has been set as a corporate philosophy. As companies decentralize, there seems to be a shift away from corporate philosophy toward individual profit centers. This has led the decision to rent versus purchase to be looked at on a regional or project-by-project basis.

  11. Nonlinear Frequency Compression

    PubMed Central

    Scollie, Susan; Glista, Danielle; Seelisch, Andreas

    2013-01-01

    Frequency lowering technologies offer an alternative amplification solution for severe to profound high frequency hearing losses. While frequency lowering technologies may improve audibility of high frequency sounds, the very nature of this processing can affect the perceived sound quality. This article reports the results from two studies that investigated the impact of a nonlinear frequency compression (NFC) algorithm on perceived sound quality. In the first study, the cutoff frequency and compression ratio parameters of the NFC algorithm were varied, and their effect on the speech quality was measured subjectively with 12 normal hearing adults, 12 normal hearing children, 13 hearing impaired adults, and 9 hearing impaired children. In the second study, 12 normal hearing and 8 hearing impaired adult listeners rated the quality of speech in quiet, speech in noise, and music after processing with a different set of NFC parameters. Results showed that the cutoff frequency parameter had more impact on sound quality ratings than the compression ratio, and that the hearing impaired adults were more tolerant to increased frequency compression than normal hearing adults. No statistically significant differences were found in the sound quality ratings of speech-in-noise and music stimuli processed through various NFC settings by hearing impaired listeners. These findings suggest that there may be an acceptable range of NFC settings for hearing impaired individuals where sound quality is not adversely affected. These results may assist an Audiologist in clinical NFC hearing aid fittings for achieving a balance between high frequency audibility and sound quality. PMID:23539261

  12. Video-compression scheme

    NASA Technical Reports Server (NTRS)

    Lum, H., Jr.; Matsumoto, Y.

    1980-01-01

    Video compression circuit divides picture into elements transmitted at reduced data rate. By sampling elements along diagonals in N-by-N picture blocks, system gives picture quality comparable to that of standard television and superior to most pseudorandom sampling schemes.

  13. Adaptive on-board data compression for spacecraft

    NASA Astrophysics Data System (ADS)

    Ward, A. K.; Nicholls, J. P.; Chaturvedi, D. C.

    1989-10-01

    Work performed by Satellites International Limited for the ESA contract 'Adaptive data compression system study for scientific satellite payload data' is described. The study was aimed at the SOHO and CLUSTER missions, in particular, and involved the identification of suitable data sources for data compression, the programming of a simulator, inclusion of the data within the simulator, and data compression. The study was comprised of an investigation of the performance of several data compression algorithms when processing suitable data, running on IBM PC only, and a comparison of two algorithms operating on three selected data sets when running on four processors: 80386, 8086, TMS320, and the T800 transputer. The study also proposed suitable architectures for a data compression unit and its position in the data acquisition chain. Activities involving the design of 1750A-based and transputer-based data compression units are also described.

  14. Locating barcodes using JPEG 2000 compressed data

    NASA Astrophysics Data System (ADS)

    Feng, Xiaojun; Gormish, Michael J.

    2005-07-01

    In this paper, a novel method is proposed to locate one-dimensional barcodes in JPEG 2000 images. The barcode locating system consists of two parts: candidate barcode location detection, barcode location verification and refinement. Both parts are designed to work in the compressed domain of JPEG 2000 images. The locations of candidate barcodes are extracted from the header data and verified by examining part of the decoded coefficients of the JPEG 2000 file. Since only a small amount of the compressed data is used, this algorithm has a low complexity relative to algorithms which use all of the pixel data.

  15. Preprototype Vapor Compression Distillation Subsystem development

    NASA Technical Reports Server (NTRS)

    Thompson, C. D.; Ellis, G. S.; Schubert, F. H.

    1981-01-01

    Vapor Compression Distillation (VCD) has evolved as the most promising approach to reclaim potable water from wastewater for future long-term manned space missions. Life Systems, Inc. (LSI), working with NASA, has developed a preprototype Vapor Compression Distillation Subsystem (VCDS) which processes wastewater at 1.4 kg/h. The preprototype unit weighs 143 kg, occupies a volume of 0.47 cu m, and will reclaim 96 percent of the available wastewater. This unit has been tested by LSI and is scheduled for further testing at NASA-JSC. This paper presents the preprototype VCDS design, configuration, performance data, test results and flight system projections.

  16. Astronomy Week in Madeira, Portugal

    NASA Astrophysics Data System (ADS)

    Augusto, P.; Sobrinho, J. L.

    2012-05-01

    The outreach programme Semanas da Astronomia (Astronomy Weeks) is held in late spring or summer on the island of Madeira, Portugal. This programme has been attracting enough interest to be mentioned in the regional press/TV/radio every year and is now, without doubt, the astronomical highlight of the year on Madeira. We believe that this programme is a good case study for showing how to attract the general public to astronomy in a small (population 250 000, area 900 km2) and fairly isolated place such as Madeira. Our Astronomy Weeks have been different each year and have so far included exhibitions, courses, talks, a forum, documentaries, observing sessions (some with blackouts), music and an astro party. These efforts may contribute towards putting Madeira on the map with respect to observational astronomy, and have also contributed to the planned installation of two observatories in the island.

  17. Compression failure of angle-ply laminates

    NASA Technical Reports Server (NTRS)

    Peel, Larry D.; Hyer, Michael W.; Shuart, Mark J.

    1991-01-01

    The present work deals with modes and mechanisms of failure in compression of angle-ply laminates. Experimental results were obtained from 42 angle-ply IM7/8551-7a specimens with a lay-up of ((plus or minus theta)/(plus or minus theta)) sub 6s where theta, the off-axis angle, ranged from 0 degrees to 90 degrees. The results showed four failure modes, these modes being a function of off-axis angle. Failure modes include fiber compression, inplane transverse tension, inplane shear, and inplane transverse compression. Excessive interlaminar shear strain was also considered as an important mode of failure. At low off-axis angles, experimentally observed values were considerably lower than published strengths. It was determined that laminate imperfections in the form of layer waviness could be a major factor in reducing compression strength. Previously developed linear buckling and geometrically nonlinear theories were used, with modifications and enhancements, to examine the influence of layer waviness on compression response. The wavy layer is described by a wave amplitude and a wave length. Linear elastic stress-strain response is assumed. The geometrically nonlinear theory, in conjunction with the maximum stress failure criterion, was used to predict compression failure and failure modes for the angle-ply laminates. A range of wave length and amplitudes were used. It was found that for 0 less than or equal to theta less than or equal to 15 degrees failure was most likely due to fiber compression. For 15 degrees less than theta less than or equal to 35 degrees, failure was most likely due to inplane transverse tension. For 35 degrees less than theta less than or equal to 70 degrees, failure was most likely due to inplane shear. For theta less than 70 degrees, failure was most likely due to inplane transverse compression. The fiber compression and transverse tension failure modes depended more heavily on wave length than on wave amplitude. Thus using a single parameter, such as a ratio of wave amplitude to wave length, to describe waviness in a laminate would be inaccurate. Throughout, results for AS4/3502, studied previously, are included for comparison. At low off-axis angles, the AS4/3502 material system was found to be less sensitive to layer waviness than IM7/8551-7a. Analytical predictions were also obtained for laminates with waviness in only some of the layers. For this type of waviness, laminate compression strength could also be considered a function of which layers in the laminate were wavy, and where those wavy layers were. Overall, the geometrically nonlinear model correlates well with experimental results.

  18. Microseismic source imaging in a compressed domain

    NASA Astrophysics Data System (ADS)

    Vera Rodriguez, Ismael; Sacchi, Mauricio D.

    2014-08-01

    Microseismic monitoring is an essential tool for the characterization of hydraulic fractures. Fast estimation of the parameters that define a microseismic event is relevant to understand and control fracture development. The amount of data contained in the microseismic records however, poses a challenge for fast continuous detection and evaluation of the microseismic source parameters. Work inspired by the emerging field of Compressive Sensing has showed that it is possible to evaluate source parameters in a compressed domain, thereby reducing processing time. This technique performs well in scenarios where the amplitudes of the signal are above the noise level, as is often the case in microseismic monitoring using downhole tools. This paper extends the idea of the compressed domain processing to scenarios of microseismic monitoring using surface arrays, where the signal amplitudes are commonly at the same level as, or below, the noise amplitudes. To achieve this, we resort to the use of an imaging operator, which has previously been found to produce better results in detection and location of microseismic events from surface arrays. The operator in our method is formed by full-waveform elastodynamic Green's functions that are band-limited by a source time function and represented in the frequency domain. Where full-waveform Green's functions are not available, ray tracing can also be used to compute the required Green's functions. Additionally, we introduce the concept of the compressed inverse, which derives directly from the compression of the migration operator using a random matrix. The described methodology reduces processing time at a cost of introducing distortions into the results. However, the amount of distortion can be managed by controlling the level of compression applied to the operator. Numerical experiments using synthetic and real data demonstrate the reductions in processing time that can be achieved and exemplify the process of selecting the compression rate that produces a tolerable amount of distortion into the results.

  19. Sympathetically cooled and compressed positron plasma

    NASA Astrophysics Data System (ADS)

    Jelenkovi?, B. M.; Newbury, A. S.; Bollinger, J. J.; Itano, W. M.; Mitchell, T. B.

    2003-06-01

    We report sympathetic cooling and compression of a few thousand positrons by laser-cooled 9Be+ ions in a Penning ion trap. The observed centrifugal separation of the two species implies approximate rigid rotation of the positrons and 9Be+ ions, and a positron density comparable to the 9Be+ ion density of ?4×109 cm-3. We use the sharpness of the separation to place a 5-K upper limit on the positron temperature of motion parallel to the magnetic field. The positron lifetime is greater than two weeks in our room-temperature Penning trap.

  20. PDF approach for compressible turbulent reacting flows

    NASA Technical Reports Server (NTRS)

    Hsu, A. T.; Tsai, Y.-L. P.; Raju, M. S.

    1993-01-01

    The objective of the present work is to develop a probability density function (pdf) turbulence model for compressible reacting flows for use with a CFD flow solver. The probability density function of the species mass fraction and enthalpy are obtained by solving a pdf evolution equation using a Monte Carlo scheme. The pdf solution procedure is coupled with a compressible CFD flow solver which provides the velocity and pressure fields. A modeled pdf equation for compressible flows, capable of capturing shock waves and suitable to the present coupling scheme, is proposed and tested. Convergence of the combined finite-volume Monte Carlo solution procedure is discussed, and an averaging procedure is developed to provide smooth Monte-Carlo solutions to ensure convergence. Two supersonic diffusion flames are studied using the proposed pdf model and the results are compared with experimental data; marked improvements over CFD solutions without pdf are observed. Preliminary applications of pdf to 3D flows are also reported.

  1. Electromyographic signal compression based on preprocessing techniques.

    PubMed

    Melo, Wheidima C; Filho, Eddie B L; Júnior, Waldir S S

    2012-01-01

    Recently, electromyographic records have been rearranged into two-dimensional arrays and encoded with image compressors, in the same way as image data. However, as a consequence of this reshaping, the correlation among signal segments is generally lost, which reduces the compression efficiency. In the present work, new preprocessing techniques for encoding electromyographic signals as two-dimensional matrices are presented, namely percentage difference sorting and relative complexity sorting, which have the potential to favor the exploitation of the intersegment dependencies. The experiments were carried out with real isometric records acquired in laboratory, that were first preprocessed and then compressed with a JPEG2000 encoder, showing that the proposed framework is effective and outperforms even state-of-the-art schemes present in the literature, in terms of PRD × Compression Ratio. PMID:23367151

  2. Multireturn compressed gated range imaging

    NASA Astrophysics Data System (ADS)

    Tsagkatakis, Grigorios; Woiselle, Arnaud; Tzagkarakis, George; Bousquet, Marc; Starck, Jean-Luc; Tsakalides, Panagiotis

    2015-03-01

    Active range imaging (RI) systems utilize actively controlled light sources emitting laser pulses that are subsequently recorded by an imaging system and used for depth profile estimation. Classical RI systems are limited by their need for a large number of frames required to obtain high resolution depth information. In this work, we propose an RI approach motivated by the recently proposed compressed sensing framework to dramatically reduce the number of necessary frames. Compressed gated range sensing employs a random gating mechanism along with state-of-the-art reconstruction algorithms for the estimation of the timing of the reflected pulses and the inference of distances. In addition to efficiency, the proposed scheme is also able to identify multiple reflected pulses that can be introduced by semi-transparent elements in the scene such as clouds, smoke, and foliage. Simulations under highly realistic conditions demonstrate that the proposed architecture is capable of accurately recovering the depth profile of a scene from as few as 10 frames at 100 depth bins resolution, even under very challenging conditions. The results further indicate that the proposed architecture is able to extract multiple reflected pulses with a minimal increase in the number of frames, in situations where state-of-the-art methods fail to accurately estimate the correct depth signals.

  3. Longwave infrared compressive hyperspectral imager

    NASA Astrophysics Data System (ADS)

    Dupuis, Julia R.; Kirby, Michael; Cosofret, Bogdan R.

    2015-06-01

    Physical Sciences Inc. (PSI) is developing a longwave infrared (LWIR) compressive sensing hyperspectral imager (CS HSI) based on a single pixel architecture for standoff vapor phase plume detection. The sensor employs novel use of a high throughput stationary interferometer and a digital micromirror device (DMD) converted for LWIR operation in place of the traditional cooled LWIR focal plane array. The CS HSI represents a substantial cost reduction over the state of the art in LWIR HSI instruments. Radiometric improvements for using the DMD in the LWIR spectral range have been identified and implemented. In addition, CS measurement and sparsity bases specifically tailored to the CS HSI instrument and chemical plume imaging have been developed and validated using LWIR hyperspectral image streams of chemical plumes. These bases enable comparable statistics to detection based on uncompressed data. In this paper, we present a system model predicting the overall performance of the CS HSI system. Results from a breadboard build and test validating the system model are reported. In addition, the measurement and sparsity basis work demonstrating the plume detection on compressed hyperspectral images is presented.

  4. Coded aperture compressive temporal imaging.

    PubMed

    Llull, Patrick; Liao, Xuejun; Yuan, Xin; Yang, Jianbo; Kittle, David; Carin, Lawrence; Sapiro, Guillermo; Brady, David J

    2013-05-01

    We use mechanical translation of a coded aperture for code division multiple access compression of video. We discuss the compressed video's temporal resolution and present experimental results for reconstructions of > 10 frames of temporal data per coded snapshot. PMID:23669910

  5. Data Compression for Helioseismology

    NASA Astrophysics Data System (ADS)

    Löptien, Björn

    2015-10-01

    Efficient data compression will play an important role for several upcoming and planned space missions involving helioseismology, such as Solar Orbiter. Solar Orbiter, to be launched in October 2018, will be the next space mission involving helioseismology. The main characteristic of Solar Orbiter lies in its orbit. The spacecraft will have an inclined solar orbit, reaching a solar latitude of up to 33 deg. This will allow, for the first time, probing the solar poles using local helioseismology. In addition, combined observations of Solar Orbiter and another helioseismic instrument will be used to study the deep interior of the Sun using stereoscopic helioseismology. The Doppler velocity and continuum intensity images of the Sun required for helioseismology will be provided by the Polarimetric and Helioseismic Imager (PHI). Major constraints for helioseismology with Solar Orbiter are the low telemetry and the (probably) short observing time. In addition, helioseismology of the solar poles requires observations close to the solar limb, even from the inclined orbit of Solar Orbiter. This gives rise to systematic errors. In this thesis, I derived a first estimate of the impact of lossy data compression on helioseismology. I put special emphasis on the Solar Orbiter mission, but my results are applicable to other planned missions as well. First, I studied the performance of PHI for helioseismology. Based on simulations of solar surface convection and a model of the PHI instrument, I generated a six-hour time-series of synthetic Doppler velocity images with the same properties as expected for PHI. Here, I focused on the impact of the point spread function, the spacecraft jitter, and of the photon noise level. The derived power spectra of solar oscillations suggest that PHI will be suitable for helioseismology. The low telemetry of Solar Orbiter requires extensive compression of the helioseismic data obtained by PHI. I evaluated the influence of data compression using data provided by the Helioseismic and Magnetic Imager (HMI). HMI is an instrument onboard the Solar Dynamics Observatory (SDO), launched in 2010. It provides full disk images with high cadence of the continuum intensity, the Doppler-velocity and the full magnetic field vector. Using HMI Doppler-velocity maps, I showed that the signal-to-noise ratio of supergranulation in time-distance helioseismology is robust regarding lossy data compression. In addition, I proved that the accuracy and precision of probing differential rotation with local correlation tracking of granulation is not severely affected by extensive lossy data compression. This indicates that the low telemetry of Solar Orbiter may not be a major challenge for helioseismology.

  6. Ultrafast compression: past, present, and future

    NASA Astrophysics Data System (ADS)

    Armstrong, Michael

    2015-06-01

    In the nearly 20 years since the first sub-ps time resolution compression wave measurements, ultrafast compression experiments have progressed from simple demonstrations to robust discoveries of extreme phenomena spanning material plasticity, solid-solid phase transitions, and shock induced chemistry. At strain rates above 109 s-1, many usual assumptions about material response no longer apply - virtually every system investigated on sub-ns time scales exhibits phenomena which are unfamiliar to conventional intuition about compression waves. This diverse of range of phenomena reflects the fundamental complexity of dynamic material behavior, but it has also been a significant impediment to a full understanding of material compression. Nonetheless, ultrafast experiments afford a number of practical advantages, primarily related to scale. Using an inexpensive table-top laser, it is possible to obtain information on materials at extreme conditions with a low laser pulse energy and a high data rate. In this talk, I will briefly review the history of ultrafast compression, significant results, and future opportunities. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  7. Compressed Air/Vacuum Transportation Techniques

    NASA Astrophysics Data System (ADS)

    Guha, Shyamal

    2011-03-01

    General theory of compressed air/vacuum transportation will be presented. In this transportation, a vehicle (such as an automobile or a rail car) is powered either by compressed air or by air at near vacuum pressure. Four version of such transportation is feasible. In all versions, a ``c-shaped'' plastic or ceramic pipe lies buried a few inches under the ground surface. This pipe carries compressed air or air at near vacuum pressure. In type I transportation, a vehicle draws compressed air (or vacuum) from this buried pipe. Using turbine or reciprocating air cylinder, mechanical power is generated from compressed air (or from vacuum). This mechanical power transferred to the wheels of an automobile (or a rail car) drives the vehicle. In type II-IV transportation techniques, a horizontal force is generated inside the plastic (or ceramic) pipe. A set of vertical and horizontal steel bars is used to transmit this force to the automobile on the road (or to a rail car on rail track). The proposed transportation system has following merits: virtually accident free; highly energy efficient; pollution free and it will not contribute to carbon dioxide emission. Some developmental work on this transportation will be needed before it can be used by the traveling public. The entire transportation system could be computer controlled.

  8. The New CCSDS Image Compression Recommendation

    NASA Technical Reports Server (NTRS)

    Yeh, Pen-Shu; Armbruster, Philippe; Kiely, Aaron; Masschelein, Bart; Moury, Gilles; Schaefer, Christoph

    2005-01-01

    The Consultative Committee for Space Data Systems (CCSDS) data compression working group has recently adopted a recommendation for image data compression, with a final release expected in 2005. The algorithm adopted in the recommendation consists of a two-dimensional discrete wavelet transform of the image, followed by progressive bit-plane coding of the transformed data. The algorithm can provide both lossless and lossy compression, and allows a user to directly control the compressed data volume or the fidelity with which the wavelet-transformed data can be reconstructed. The algorithm is suitable for both frame-based image data and scan-based sensor data, and has applications for near-Earth and deep-space missions. The standard will be accompanied by free software sources on a future web site. An Application-Specific Integrated Circuit (ASIC) implementation of the compressor is currently under development. This paper describes the compression algorithm along with the requirements that drove the selection of the algorithm. Performance results and comparisons with other compressors are given for a test set of space images.

  9. Multimode Data-Compression System

    NASA Technical Reports Server (NTRS)

    Fang, Wai-Chi

    1996-01-01

    Data-compression system developed to satisfy need for high-speed, high-performance compression of data from sources as diverse as medical images, high-definition television images, audio signals, readouts from scientific instruments, and binary data files. Maximum data-transmission capability of communication channel or storage capacity of storage device multiplied by approximately compression ratio. Various combinations of lossless and lossy compression chosen to suit various data streams.

  10. Predictive Encoding in Text Compression.

    ERIC Educational Resources Information Center

    Raita, Timo; Teuhola, Jukka

    1989-01-01

    Presents three text compression methods of increasing power and evaluates each based on the trade-off between compression gain and processing time. The advantages of using hash coding for speed and optimal arithmetic coding to successor information for compression gain are discussed. (26 references) (Author/CLB)

  11. Basic cluster compression algorithm

    NASA Technical Reports Server (NTRS)

    Hilbert, E. E.; Lee, J.

    1980-01-01

    Feature extraction and data compression of LANDSAT data is accomplished by BCCA program which reduces costs associated with transmitting, storing, distributing, and interpreting multispectral image data. Algorithm uses spatially local clustering to extract features from image data to describe spectral characteristics of data set. Approach requires only simple repetitive computations, and parallel processing can be used for very high data rates. Program is written in FORTRAN IV for batch execution and has been implemented on SEL 32/55.

  12. Cerebral compression by myeloma.

    PubMed Central

    Stark, R J; Henson, R A

    1981-01-01

    A patient presented with right hemiparesis, dysphasia and a large, palpable, left frontoparietal mass arising from the calvarial diploe. A diagnosis of multiple myeloma was made on radiological and biochemical grounds, together with bone marrow examination. Few cases of cerebral compression by a massive plasmacytoma have been reported, but in some surgical management produced clinical deterioration. The present case was treated with radiotherapy and chemotherapy, with satisfactory results. Images PMID:7310424

  13. Variable Quality Compression of Fluid Dynamical Data Sets Using a 3D DCT Technique

    NASA Astrophysics Data System (ADS)

    Loddoch, A.; Schmalzl, J.

    2005-12-01

    In this work we present a data compression scheme that is especially suited for the compression of data sets resulting from computational fluid dynamics (CFD). By adopting the concept of the JPEG compression standard and extending the approach of Schmalzl (Schmalzl, J. Using standard image compression algorithms to store data from computational fluid dynamics. Computers and Geosciences, 29, 10211031, 2003) we employ a three-dimensional discrete cosine transform of the data. The resulting frequency components are rearranged, quantized and finally stored using Huffman-encoding and standard variable length integer codes. The compression ratio and also the introduced loss of accuracy can be adjusted by means of two compression parameters to give the desired compression profile. Using the proposed technique compression ratios of more than 60:1 are possible with an mean error of the compressed data of less than 0.1%.

  14. Learning random networks for compression of still and moving images

    NASA Technical Reports Server (NTRS)

    Gelenbe, Erol; Sungur, Mert; Cramer, Christopher

    1994-01-01

    Image compression for both still and moving images is an extremely important area of investigation, with numerous applications to videoconferencing, interactive education, home entertainment, and potential applications to earth observations, medical imaging, digital libraries, and many other areas. We describe work on a neural network methodology to compress/decompress still and moving images. We use the 'point-process' type neural network model which is closer to biophysical reality than standard models, and yet is mathematically much more tractable. We currently achieve compression ratios of the order of 120:1 for moving grey-level images, based on a combination of motion detection and compression. The observed signal-to-noise ratio varies from values above 25 to more than 35. The method is computationally fast so that compression and decompression can be carried out in real-time. It uses the adaptive capabilities of a set of neural networks so as to select varying compression ratios in real-time as a function of quality achieved. It also uses a motion detector which will avoid retransmitting portions of the image which have varied little from the previous frame. Further improvements can be achieved by using on-line learning during compression, and by appropriate compensation of nonlinearities in the compression/decompression scheme. We expect to go well beyond the 250:1 compression level for color images with good quality levels.

  15. Deterministic compressed sensing and quantization

    NASA Astrophysics Data System (ADS)

    Ahmadieh, Arman; Yilmaz, Özgur

    2015-09-01

    Compressed Sensing (CS) is a sampling paradigm used for acquiring sparse or compressible signals from a seemingly incomplete set of measurements. In any practical application with our digitally driven technology, these "compressive measurements" are quantized and thus they do not have infinite precision. So far, the theory of quantization in CS has mainly focused on compressive sampling systems designed with random measurement matrices. In this note, we turn our attention to "deterministic compressed sensing". Specifically, we focus on quantization in CS with chirp sensing matrices and present quantization approaches and numerical experiments.

  16. Extracting Constitutive Stress-Strain Behavior of Microscopic Phases by Micropillar Compression

    SciTech Connect

    Williams, J. J.; Walters, Jennifer; Wang, Mingyue; Chawla, N.; Rohatgi, Aashish

    2013-02-01

    The manuscript describes how micropillar compression technique can be used to perform uniaxial compression tests within individual grains so as to generate local-scale constitutive behavior which, otherwise cannot be ascertained from the conventional macroscale compression test techniques. The manuscript uses steel and magnesium alloys as an example. A portion of the magnesium work was performed at PNNL.

  17. The Four Day School Week. Research Brief

    ERIC Educational Resources Information Center

    Muir, Mike

    2013-01-01

    Can four-day school weeks help districts save money? How do districts overcome the barriers of moving to a four-day week? What is the effect of a four-day week on students, staff and the community? This paper enumerates the benefits for students and teachers of four-day school weeks. Recommendations for implementation of a four-day week are also…

  18. Fast Compressive Tracking.

    PubMed

    Zhang, Kaihua; Zhang, Lei; Yang, Ming-Hsuan

    2014-10-01

    It is a challenging task to develop effective and efficient appearance models for robust object tracking due to factors such as pose variation, illumination change, occlusion, and motion blur. Existing online tracking algorithms often update models with samples from observations in recent frames. Despite much success has been demonstrated, numerous issues remain to be addressed. First, while these adaptive appearance models are data-dependent, there does not exist sufficient amount of data for online algorithms to learn at the outset. Second, online tracking algorithms often encounter the drift problems. As a result of self-taught learning, misaligned samples are likely to be added and degrade the appearance models. In this paper, we propose a simple yet effective and efficient tracking algorithm with an appearance model based on features extracted from a multiscale image feature space with data-independent basis. The proposed appearance model employs non-adaptive random projections that preserve the structure of the image feature space of objects. A very sparse measurement matrix is constructed to efficiently extract the features for the appearance model. We compress sample images of the foreground target and the background using the same sparse measurement matrix. The tracking task is formulated as a binary classification via a naive Bayes classifier with online update in the compressed domain. A coarse-to-fine search strategy is adopted to further reduce the computational complexity in the detection procedure. The proposed compressive tracking algorithm runs in real-time and performs favorably against state-of-the-art methods on challenging sequences in terms of efficiency, accuracy and robustness. PMID:26352631

  19. [Evaluation of irreversible compressed images in computed radiography using physical image quality measures].

    PubMed

    Watanabe, Haruyuki; Tsai, Du-Yih; Lee, Yongbum; Nakamura, Tomohiro; Miyazaki, Masanori; Kuramochi, Yoshio; Kojima, Katsuyuki

    2009-12-20

    Joint photographic experts group(JPEG)and JPEG2000 are widely used as image compression algorithms in medical image database systems. Compressed images have been mainly evaluated by visual assessment on acceptable compression levels in clinical studies. However, to the best of our knowledge, little work has been done to clarify image properties based on physical analysis. In this work, investigations were made to clarify image properties based on physical analysis and to discuss the major causes of degradation related to compression ratios. The physical properties of JPEG2000-compressed and JPEG-compressed images in computed radiography(CR)were compared by measuring the characteristic curve, modulation transfer function(MTF), noise power spectrum(NPS), peak signal-to-noise ratio(PSNR), contrast-to-noise ratio(CNR), and noise equivalent quanta(NEQ). In the MTF measurement, the MTFs of JPEG at high compression ratio showed pronounced degradation at all frequencies. The NPS values of JPEG2000 tend to decrease considerably compared to that of the JPEG at all frequencies with the increase of compression ratio. Furthermore, JPEG2000 images showed higher PSNR, CNR, and NEQ values than JPEG images in the same compression ratio. In these signal-to-noise ratio measurements, good reproducibility of JPEG2000 images was achieved. Overall, JPEG2000 compressed images were far superior to JPEG compressed images. In the physical properties measured, these physical analyses are useful to comprehend physical properties for each irreversible compressed image related to compression ratios in CR. PMID:20124739

  20. SeqCompress: an algorithm for biological sequence compression.

    PubMed

    Sardaraz, Muhammad; Tahir, Muhammad; Ikram, Ataul Aziz; Bajwa, Hassan

    2014-10-01

    The growth of Next Generation Sequencing technologies presents significant research challenges, specifically to design bioinformatics tools that handle massive amount of data efficiently. Biological sequence data storage cost has become a noticeable proportion of total cost in the generation and analysis. Particularly increase in DNA sequencing rate is significantly outstripping the rate of increase in disk storage capacity, which may go beyond the limit of storage capacity. It is essential to develop algorithms that handle large data sets via better memory management. This article presents a DNA sequence compression algorithm SeqCompress that copes with the space complexity of biological sequences. The algorithm is based on lossless data compression and uses statistical model as well as arithmetic coding to compress DNA sequences. The proposed algorithm is compared with recent specialized compression tools for biological sequences. Experimental results show that proposed algorithm has better compression gain as compared to other existing algorithms. PMID:25173568

  1. Comparative data compression techniques and multi-compression results

    NASA Astrophysics Data System (ADS)

    Hasan, M. R.; Ibrahimy, M. I.; Motakabber, S. M. A.; Ferdaus, M. M.; Khan, M. N. H.

    2013-12-01

    Data compression is very necessary in business data processing, because of the cost savings that it offers and the large volume of data manipulated in many business applications. It is a method or system for transmitting a digital image (i.e., an array of pixels) from a digital data source to a digital data receiver. More the size of the data be smaller, it provides better transmission speed and saves time. In this communication, we always want to transmit data efficiently and noise freely. This paper will provide some compression techniques for lossless text type data compression and comparative result of multiple and single compression, that will help to find out better compression output and to develop compression algorithms.

  2. Sampling video compression system

    NASA Technical Reports Server (NTRS)

    Matsumoto, Y.; Lum, H. (Inventor)

    1977-01-01

    A system for transmitting video signal of compressed bandwidth is described. The transmitting station is provided with circuitry for dividing a picture to be transmitted into a plurality of blocks containing a checkerboard pattern of picture elements. Video signals along corresponding diagonal rows of picture elements in the respective blocks are regularly sampled. A transmitter responsive to the output of the sampling circuitry is included for transmitting the sampled video signals of one frame at a reduced bandwidth over a communication channel. The receiving station is provided with a frame memory for temporarily storing transmitted video signals of one frame at the original high bandwidth frequency.

  3. Avalanches in Wood Compression.

    PubMed

    Mäkinen, T; Miksic, A; Ovaska, M; Alava, Mikko J

    2015-07-31

    Wood is a multiscale material exhibiting a complex viscoplastic response. We study avalanches in small wood samples in compression. "Woodquakes" measured by acoustic emission are surprisingly similar to earthquakes and crackling noise in rocks and laboratory tests on brittle materials. Both the distributions of event energies and of waiting (silent) times follow power laws. The stress-strain response exhibits clear signatures of localization of deformation to "weak spots" or softwood layers, as identified using digital image correlation. Even though material structure-dependent localization takes place, the avalanche behavior remains scale-free. PMID:26274428

  4. Compression machine cavity control

    NASA Astrophysics Data System (ADS)

    Floersch, R. H.

    1982-06-01

    A system design that uses closed loop control of the hydraulic system of a compression transfer press (used to make filled elastomer parts) has resulted in improved accuracy and repeatability in the speed and pressure control segments during the critical forming stages before part cure. The design uses a microprocessor to supply set points and timing functions to the control system. The cascade control system consists of a specially designed outer loop controller that feeds set point information to the inner loop valve controller. Presented are the final hardware and software architectures for this design, as well as a report on system performance.

  5. Avalanches in Wood Compression

    NASA Astrophysics Data System (ADS)

    Mäkinen, T.; Miksic, A.; Ovaska, M.; Alava, Mikko J.

    2015-07-01

    Wood is a multiscale material exhibiting a complex viscoplastic response. We study avalanches in small wood samples in compression. "Woodquakes" measured by acoustic emission are surprisingly similar to earthquakes and crackling noise in rocks and laboratory tests on brittle materials. Both the distributions of event energies and of waiting (silent) times follow power laws. The stress-strain response exhibits clear signatures of localization of deformation to "weak spots" or softwood layers, as identified using digital image correlation. Even though material structure-dependent localization takes place, the avalanche behavior remains scale-free.

  6. Compression test apparatus

    NASA Technical Reports Server (NTRS)

    Shanks, G. C. (inventor)

    1981-01-01

    An apparatus for compressive testing of a test specimen may comprise vertically spaced upper and lower platen members between which a test specimen may be placed. The platen members are supported by a fixed support assembly. A load indicator is interposed between the upper platen member and the support assembly for supporting the total weight of the upper platen member and any additional weight which may be placed on it. Operating means are provided for moving the lower platen member upwardly toward the upper platen member whereby an increasing portion of the total weight is transferred from the load indicator to the test specimen.

  7. Compression and Entrapment Syndromes

    PubMed Central

    Heffernan, L.P.; Benstead, T.J.

    1987-01-01

    Family physicians are often confronted by patients who present with pain, numbness and weakness. Such complaints, when confined to a single extremity, most particularly to a restricted portion of the extremity, may indicate focal dysfunction of peripheral nerve structures arising from compression and/or entrapment, to which such nerves are selectively vulnerable. The authors of this article consider the paramount clinical features that allow the clinician to arrive at a correct diagnosis, reviews major points in differential diagnosis, and suggest appropriate management strategies. PMID:21263858

  8. Compression of Semesters or Intensity of Study: What is it that Increases Student Success?

    ERIC Educational Resources Information Center

    Spurling, Steven

    This study examined the relationship between intensity of study (defined as more hours per week of class within a subject matter area) and student success. The researcher identified two possible methods for increasing the intensity of study: (1) Compression Hypothesis--shortening the length of terms and increasing the amount of time per week spent…

  9. Curriculum Characteristics of Time-Compressed Course in a U.S. Higher Education Institution

    ERIC Educational Resources Information Center

    Hyun, Eunsook; Kretovics, Mark; Crowe, Alicia

    2006-01-01

    The study explored characteristics of the curriculum practice of higher education faculty in the context of time-compressed (e.g., 5-6 weeks) courses as compared with regular term (15-16 weeks) courses. The researchers used open-ended questions on a web-based survey at a large doctoral-extensive university in a Midwestern state in the United…

  10. Image compression in local helioseismology

    NASA Astrophysics Data System (ADS)

    Löptien, B.; Birch, A. C.; Gizon, L.; Schou, J.

    2014-11-01

    Context. Several upcoming helioseismology space missions are very limited in telemetry and will have to perform extensive data compression. This requires the development of new methods of data compression. Aims: We give an overview of the influence of lossy data compression on local helioseismology. We investigate the effects of several lossy compression methods (quantization, JPEG compression, and smoothing and subsampling) on power spectra and time-distance measurements of supergranulation flows at disk center. Methods: We applied different compression methods to tracked and remapped Dopplergrams obtained by the Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory. We determined the signal-to-noise ratio of the travel times computed from the compressed data as a function of the compression efficiency. Results: The basic helioseismic measurements that we consider are very robust to lossy data compression. Even if only the sign of the velocity is used, time-distance helioseismology is still possible. We achieve the best results by applying JPEG compression on spatially subsampled data. However, our conclusions are only valid for supergranulation flows at disk center and may not be valid for all helioseismology applications.

  11. Ultrasound beamforming using compressed data.

    PubMed

    Li, Yen-Feng; Li, Pai-Chi

    2012-05-01

    The rapid advancements in electronics technologies have made software-based beamformers for ultrasound array imaging feasible, thus facilitating the rapid development of high-performance and potentially low-cost systems. However, one challenge to realizing a fully software-based system is transferring data from the analog front end to the software back end at rates of up to a few gigabits per second. This study investigated the use of data compression to reduce the data transfer requirements and optimize the associated trade-off with beamforming quality. JPEG and JPEG2000 compression techniques were adopted. The acoustic data of a line phantom were acquired with a 128-channel array transducer at a center frequency of 3.5 MHz, and the acoustic data of a cyst phantom were acquired with a 64-channel array transducer at a center frequency of 3.33 MHz. The receive-channel data associated with each transmit event are separated into 8 × 8 blocks and several tiles before JPEG and JPEG2000 data compression is applied, respectively. In one scheme, the compression was applied to raw RF data, while in another only the amplitude of baseband data was compressed. The maximum compression ratio of RF data compression to produce an average error of lower than 5 dB was 15 with JPEG compression and 20 with JPEG2000 compression. The image quality is higher with baseband amplitude data compression than with RF data compression; although the maximum overall compression ratio (compared with the original RF data size), which was limited by the data size of uncompressed phase data, was lower than 12, the average error in this case was lower than 1 dB when the compression ratio was lower than 8. PMID:22434817

  12. Compression of Martian atmosphere for production of oxygen

    NASA Technical Reports Server (NTRS)

    Lynch, D. C.; Cutler, A. H.; Nolan, P. E.

    1991-01-01

    The compression of CO2 from the Martian atmosphere for production of O2 via an electrochemical cell is addressed. Design specifications call for an oxygen production rate of 10 kg per day and for compression of 50 times that mass of CO2. Those specifications require a compression rate of over 770 cfm at standard Martian temperature and pressure (SMTP). Much of the CO2 being compressed represents waste, unless it can be recycled. Recycling can reduce the volume of gas that must be compressed to 40 cfm at SMTP. That volume reduction represents significant mass savings in the compressor, heating equipment, filters, and energy source. Successful recycle of the gas requires separation of CO (produced in the electrochemical cell) from CO2, N2, and Ar found in the Martian atmosphere. That aspect was the focus of this work.

  13. Digital mammography, cancer screening: Factors important for image compression

    NASA Technical Reports Server (NTRS)

    Clarke, Laurence P.; Blaine, G. James; Doi, Kunio; Yaffe, Martin J.; Shtern, Faina; Brown, G. Stephen; Winfield, Daniel L.; Kallergi, Maria

    1993-01-01

    The use of digital mammography for breast cancer screening poses several novel problems such as development of digital sensors, computer assisted diagnosis (CAD) methods for image noise suppression, enhancement, and pattern recognition, compression algorithms for image storage, transmission, and remote diagnosis. X-ray digital mammography using novel direct digital detection schemes or film digitizers results in large data sets and, therefore, image compression methods will play a significant role in the image processing and analysis by CAD techniques. In view of the extensive compression required, the relative merit of 'virtually lossless' versus lossy methods should be determined. A brief overview is presented here of the developments of digital sensors, CAD, and compression methods currently proposed and tested for mammography. The objective of the NCI/NASA Working Group on Digital Mammography is to stimulate the interest of the image processing and compression scientific community for this medical application and identify possible dual use technologies within the NASA centers.

  14. Restricted isometry properties and nonconvex compressive sensing

    NASA Astrophysics Data System (ADS)

    Chartrand, Rick; Staneva, Valentina

    2008-06-01

    The recently emerged field known as compressive sensing has produced powerful results showing the ability to recover sparse signals from surprisingly few linear measurements, using ell1 minimization. In previous work, numerical experiments showed that ellp minimization with 0 < p < 1 recovers sparse signals from fewer linear measurements than does ell1 minimization. It was also shown that a weaker restricted isometry property is sufficient to guarantee perfect recovery in the ellp case. In this work, we generalize this result to an ellp variant of the restricted isometry property, and then determine how many random, Gaussian measurements are sufficient for the condition to hold with high probability. The resulting sufficient condition is met by fewer measurements for smaller p. This adds to the theoretical justification for the methods already being applied to replacing high-dose CT scans with a small number of x-rays and reducing MRI scanning time. The potential benefits extend to any application of compressive sensing.

  15. Perceptually Lossless Wavelet Compression

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Yang, Gloria Y.; Solomon, Joshua A.; Villasenor, John

    1996-01-01

    The Discrete Wavelet Transform (DWT) decomposes an image into bands that vary in spatial frequency and orientation. It is widely used for image compression. Measures of the visibility of DWT quantization errors are required to achieve optimal compression. Uniform quantization of a single band of coefficients results in an artifact that is the sum of a lattice of random amplitude basis functions of the corresponding DWT synthesis filter, which we call DWT uniform quantization noise. We measured visual detection thresholds for samples of DWT uniform quantization noise in Y, Cb, and Cr color channels. The spatial frequency of a wavelet is r 2(exp -1), where r is display visual resolution in pixels/degree, and L is the wavelet level. Amplitude thresholds increase rapidly with spatial frequency. Thresholds also increase from Y to Cr to Cb, and with orientation from low-pass to horizontal/vertical to diagonal. We propose a mathematical model for DWT noise detection thresholds that is a function of level, orientation, and display visual resolution. This allows calculation of a 'perceptually lossless' quantization matrix for which all errors are in theory below the visual threshold. The model may also be used as the basis for adaptive quantization schemes.

  16. Compressive light field sensing.

    PubMed

    Babacan, S Derin; Ansorge, Reto; Luessi, Martin; Matarán, Pablo Ruiz; Molina, Rafael; Katsaggelos, Aggelos K

    2012-12-01

    We propose a novel design for light field image acquisition based on compressive sensing principles. By placing a randomly coded mask at the aperture of a camera, incoherent measurements of the light passing through different parts of the lens are encoded in the captured images. Each captured image is a random linear combination of different angular views of a scene. The encoded images are then used to recover the original light field image via a novel Bayesian reconstruction algorithm. Using the principles of compressive sensing, we show that light field images with a large number of angular views can be recovered from only a few acquisitions. Moreover, the proposed acquisition and recovery method provides light field images with high spatial resolution and signal-to-noise-ratio, and therefore is not affected by limitations common to existing light field camera designs. We present a prototype camera design based on the proposed framework by modifying a regular digital camera. Finally, we demonstrate the effectiveness of the proposed system using experimental results with both synthetic and real images. PMID:22851261

  17. GPA/GPSA/OSU-Okmulgee natural gas compression technician training program

    SciTech Connect

    Doede, S.

    1999-07-01

    Approximately one year ago, OSU-Okmulgee and the Gas Processors Association began discussions about the possibility of developing a natural Gas Technician Training Program for GPA members. Following a presentation to the Membership and Services Committee, Chairman John Ehlers solicited and obtained the approval of the GPA Executive Committee to sponsor the program. Participation in the program was also made available to GPSA members. The purpose of the program is to upgrade the technical competency and professional level of incoming natural gas compression technicians. It educates students to analytically diagnose, service and maintain gas compression equipment and systems using industry recommended procedures, special tools and service information. It also provides course content, which will enable successful graduates to advance in position after additional experience, and to understand new systems, technologies and components as they are introduced. The two-year Associate-In-Applied Science Degree program includes six successive college semesters. Nearly one-half of the time is designated for technical/academic education at Oklahoma State University-Okmulgee with the balance of time allocated for on-the-job internship experiences at sponsoring GPA/GPSA members. Each block of technical education and general education course work is followed by an immediate work experience time period designated to reinforce the technical and general education. These time periods are approximately seven and one-half weeks in length each. It is essential for the success of the students and the program that the students' education at OSU-Okmulgee and work experiences at GPA/GPSA member facilities be closely aligned for maximum student learning and retention. In addition to technical classes on gas compression equipment and components, the courses offered in math, speech, technical writing, psychology and ethics for example, prepare students to be able to communicate well, get along with others and be responsible and productive employees.

  18. COMPRESSION SEAL AND SEALING MATERIAL THEREFOR

    DOEpatents

    Branin, T.G.

    1962-05-29

    This patent relates to compression seal and more particularly to a seaiing material therefor. The sealing surface is a coating consisting of alternate layers of gold and of a non-gold metal having similar plastic flow properties under pressure as gold. The coating is substantially free from oxidation effects when exposed to ambient atmosphere and does not become brittle when worked, as in a valve. (AEC)

  19. Recent progress in compressible turbulence

    NASA Astrophysics Data System (ADS)

    Chen, Shiyi; Xia, Zhenhua; Wang, Jianchun; Yang, Yantao

    2015-06-01

    In this paper, we review some recent studies on compressible turbulence conducted by the authors' group, which include fundamental studies on compressible isotropic turbulence (CIT) and applied studies on developing a constrained large eddy simulation (CLES) for wall-bounded turbulence. In the first part, we begin with a newly proposed hybrid compact-weighted essentially nonoscillatory (WENO) scheme for a CIT simulation that has been used to construct a systematic database of CIT. Using this database various fundamental properties of compressible turbulence have been examined, including the statistics and scaling of compressible modes, the shocklet-turbulence interaction, the effect of local compressibility on small scales, the kinetic energy cascade, and some preliminary results from a Lagrangian point of view. In the second part, the idea and formulas of the CLES are reviewed, followed by the validations of CLES and some applications in compressible engineering problems.

  20. Energy transfer in compressible turbulence

    NASA Technical Reports Server (NTRS)

    Bataille, Francoise; Zhou, YE; Bertoglio, Jean-Pierre

    1995-01-01

    This letter investigates the compressible energy transfer process. We extend a methodology developed originally for incompressible turbulence and use databases from numerical simulations of a weak compressible turbulence based on Eddy-Damped-Quasi-Normal-Markovian (EDQNM) closure. In order to analyze the compressible mode directly, the well known Helmholtz decomposition is used. While the compressible component has very little influence on the solenoidal part, we found that almost all of the compressible turbulence energy is received from its solenoidal counterpart. We focus on the most fundamental building block of the energy transfer process, the triadic interactions. This analysis leads us to conclude that, at low turbulent Mach number, the compressible energy transfer process is dominated by a local radiative transfer (absorption) in both inertial and energy containing ranges.

  1. Compressive sensing in medical imaging

    PubMed Central

    Graff, Christian G.; Sidky, Emil Y.

    2015-01-01

    The promise of compressive sensing, exploitation of compressibility to achieve high quality image reconstructions with less data, has attracted a great deal of attention in the medical imaging community. At the Compressed Sensing Incubator meeting held in April 2014 at OSA Headquarters in Washington, DC, presentations were given summarizing some of the research efforts ongoing in compressive sensing for x-ray computed tomography and magnetic resonance imaging systems. This article provides an expanded version of these presentations. Sparsity-exploiting reconstruction algorithms that have gained popularity in the medical imaging community are studied, and examples of clinical applications that could benefit from compressive sensing ideas are provided. The current and potential future impact of compressive sensing on the medical imaging field is discussed. PMID:25968400

  2. Energy savings with compressed air

    SciTech Connect

    Risi, J.D.

    1995-12-31

    The production of compressed air can be one of the most expensive processes in manufacturing facilities. Annual operating costs of air compressors, dryers and supporting equipment can account for up to 70% of the total electric bill. Because the greatest single cost of manufacturing may be attributed to compressed-air, it follows that the greatest potential for energy conservation may also exist with the compressed-air equipment. Opportunities for cost savings related to compressed air include, but are not limited to, the following: compressor waste heat recovery; compressed-air leak reduction; the use of outside air for compressor intakes; compressor control; air-pressure reduction; compressor selection (type, size, etc.); and internal combustion engine-driven air compressor. This paper shows that several energy conservation opportunities exist that are simple to understand and cost-effective to implement. Compressed-air systems should be an integral part of every energy management program.

  3. New Regenerative Cycle for Vapor Compression Refrigeration

    SciTech Connect

    Mark J. Bergander

    2005-08-29

    The main objective of this project is to confirm on a well-instrumented prototype the theoretically derived claims of higher efficiency and coefficient of performance for geothermal heat pumps based on a new regenerative thermodynamic cycle as comparing to existing technology. In order to demonstrate the improved performance of the prototype, it will be compared to published parameters of commercially available geothermal heat pumps manufactured by US and foreign companies. Other objectives are to optimize the design parameters and to determine the economic viability of the new technology. Background (as stated in the proposal): The proposed technology closely relates to EERE mission by improving energy efficiency, bringing clean, reliable and affordable heating and cooling to the residential and commercial buildings and reducing greenhouse gases emission. It can provide the same amount of heating and cooling with considerably less use of electrical energy and consequently has a potential of reducing our nations dependence on foreign oil. The theoretical basis for the proposed thermodynamic cycle was previously developed and was originally called a dynamic equilibrium method. This theory considers the dynamic equations of state of the working fluid and proposes the methods for modification of T-S trajectories of adiabatic transformation by changing dynamic properties of gas, such as flow rate, speed and acceleration. The substance of this proposal is a thermodynamic cycle characterized by the regenerative use of the potential energy of two-phase flow expansion, which in traditional systems is lost in expansion valves. The essential new features of the process are: (1) The application of two-step throttling of the working fluid and two-step compression of its vapor phase. (2) Use of a compressor as the initial step compression and a jet device as a second step, where throttling and compression are combined. (3) Controlled ratio of a working fluid at the first and second step of compression. In the proposed system, the compressor compresses the vapor only to 50-60% of the final pressure, while the additional compression is provided by a jet device using internal potential energy of the working fluid flow. Therefore, the amount of mechanical energy required by a compressor is significantly reduced, resulting in the increase of efficiency (either COP or EER). The novelty of the cycle is in the equipment and in the way the multi-staging is accomplished. The anticipated result will be a new refrigeration system that requires less energy to accomplish a cooling task. The application of this technology will be for more efficient designs of: (1) Industrial chillers, (2) Refrigeration plants, (3) Heat pumps, (4) Gas Liquefaction plants, (5) Cryogenic systems.

  4. The quest for 'diagnostically lossless' medical image compression: a comparative study of objective quality metrics for compressed medical images

    NASA Astrophysics Data System (ADS)

    Kowalik-Urbaniak, Ilona; Brunet, Dominique; Wang, Jiheng; Koff, David; Smolarski-Koff, Nadine; Vrscay, Edward R.; Wallace, Bill; Wang, Zhou

    2014-03-01

    Our study, involving a collaboration with radiologists (DK,NSK) as well as a leading international developer of medical imaging software (AGFA), is primarily concerned with improved methods of assessing the diagnostic quality of compressed medical images and the investigation of compression artifacts resulting from JPEG and JPEG2000. In this work, we compare the performances of the Structural Similarity quality measure (SSIM), MSE/PSNR, compression ratio CR and JPEG quality factor Q, based on experimental data collected in two experiments involving radiologists. An ROC and Kolmogorov-Smirnov analysis indicates that compression ratio is not always a good indicator of visual quality. Moreover, SSIM demonstrates the best performance, i.e., it provides the closest match to the radiologists' assessments. We also show that a weighted Youden index1 and curve tting method can provide SSIM and MSE thresholds for acceptable compression ratios.

  5. Compression therapy of leg ulcers with PAOD.

    PubMed

    Ladwig, Andrea; Haase, Hermann; Bichel, Jens; Schuren, Jan; Jünger, Michael

    2014-05-19

    Objectives: To assess the clinical safety of a new short-stretch 2-layer compression system (3M(tm) Coban(tm) 2 Lite) in patients with peripheral arterial occlusive disease (PAOD). This system combines a low resting pressure with a high working pressure. Methods: A pilot study was performed in 15 subjects with moderate PAOD, i.e. an ABPI of 0.5-0.8. Co-existing chronic venous insufficiency or leg ulcer was not mandatory. All subjects received the compression system which was reapplied at each study visit (days 1, 2, 3, 4, 7, 10, 14). The safety parameters were: sub-bandage pressure immediately after application, pressure-related skin damage, hypoxia-related pain, and adverse events. A product comfort questionnaire was completed at the last visit. Results: The average sub-bandage pressure of 30?mmHg defined by the protocol was achieved. No pressure-related skin damage or hypoxia-related pain was found. The reported adverse device effects were as expected for compression therapies, including dry skin and pruritus. The product comfort questionnaire completed by the subjects showed a good tolerability profile. Conclusion: The short-stretch 2-layer compression system (3M(tm) Coban(tm) 2 Lite) was safe and well tolerated in subjects with moderate PAOD. PMID:24843079

  6. Seismic full waveform inversion from compressive measurements

    NASA Astrophysics Data System (ADS)

    Ramirez, Ana; Arce, Gonzalo R.

    2015-05-01

    Traditional methods in seismic acquisition require sources and geophones that are uniformly located along a spatial line, using the Nyquist sampling rate. Depending on the area to be explored, it can be necessary to use seismic surveys with large offsets, or decrease the separation between adjacent geophones to improve the resolution, which generates very high volumes of data. It makes the exploration process more difficult and particularly expensive. This work presents the reconstruction of a compressive set of seismic traces acquired using the compressive sensing paradigm where the pair of sources and geophones are randomly located along the spatial line. The recovery of the wavefield from compressive measurements is feasible due to the capabilities of Curvelets on representing wave propagators with only a small set of coefficients. The method first uses the compressive samples to find a sparse vector representation of each pixel in a 2-D Curvelet dictionary. The sparse vector representation is estimated by solving a sparsity constrained optimization problem using the Gradient Projection for Sparse Reconstruction (GPSR) method. The estimated vector is then used to compute the seismic velocity profiles via acoustic Full Waveform Inversion (FWI). Simulations of the reconstructed image gathers and the resulting seismic velocity profiles illustrate the performance of the method. An improvement in the resulting images is obtained in comparison with traditional F-K filtering used in seismic data processing when traces are missing.

  7. Intermittent pneumatic compression in immobile patients.

    PubMed

    Partsch, Hugo

    2008-06-01

    The purpose of this study is to stress the value of using intermittent pneumatic compression (IPC) in immobile patients. The use of IPC helps prevent limb oedema and the associated skin changes frequently seen on the legs of the immobile patient. Oedema formation is caused by an increase of fluid extravasation, while skin changes including leg ulcers are mainly because of a deficiency of the venous and lymphatic pumps. Conventional compression stockings and bandages impede leg swelling but are less efficient in supporting the deficient veno-lymphatic pump when patients are unable to move. In this situation, actively compressing the limb using IPC is a very meaningful and effective treatment option. Because of a lack of literature on the specific indication of IPC in immobile patients, experimental studies and randomised controlled trials in similar situations are reviewed. IPC is a very effective although underused treatment modality, especially in immobile, wheelchair-bound patients. By inflation and deflation of the air-filled garments, IPC produces cycles of pressure waves on the leg, thus mimicking the working and resting pressures applied by compression bandages. IPC not only reduces leg swelling but also augments the veno-lymphatic pump, which is essential for the restoration of the damaged microcirculation of the skin. PMID:18593389

  8. Compression in Molecular Simulation Datasets

    PubMed Central

    Kumar, Anand; Zhu, Xingquan; Tu, Yi-Cheng; Pandit, Sagar

    2015-01-01

    In this paper, we present a compression framework, for molecular dynamics (MD) simulation data, which yields significant performance by combining the strength of principal component analysis (PCA) and discrete cosine transform (DCT). Though it is a lossy compression technique, the effect on analytics performed on decompressed data is very minimal. Compression ratio up to 13 is achieved with acceptable errors in results of analytical functions.

  9. Shock compression of precompressed deuterium

    SciTech Connect

    Armstrong, M R; Crowhurst, J C; Zaug, J M; Bastea, S; Goncharov, A F; Militzer, B

    2011-07-31

    Here we report quasi-isentropic dynamic compression and thermodynamic characterization of solid, precompressed deuterium over an ultrafast time scale (< 100 ps) and a microscopic length scale (< 1 {micro}m). We further report a fast transition in shock wave compressed solid deuterium that is consistent with the ramp to shock transition, with a time scale of less than 10 ps. These results suggest that high-density dynamic compression of hydrogen may be possible on microscopic length scales.

  10. Compression of intensity interferometry signals

    NASA Astrophysics Data System (ADS)

    Ribak, Erez N.; Shulamy, Yaron

    2016-02-01

    Correlations between photon currents from separate light-collectors provide information on the shape of the source. When the light-collectors are well separated, for example in space, transmission of these currents to a central correlator is limited by band-width. We study the possibility of compression of the photon fluxes and find that traditional compression methods have a similar chance of achieving this goal compared to compressed sensing.

  11. Adiabatic compressibility of globular proteins.

    PubMed Central

    Gavish, B; Gratton, E; Hardy, C J

    1983-01-01

    The adiabatic compressibility of several globular proteins has been measured by using an ultrasonic technique in the frequency range 0.5 to 10 MHz. The contributions to the measured compressibility from the protein matrix and from surface processes involving ionization of side chains and solvation effects are discussed. The internal protein compressibility is very low, indicating the existence of "dynamic domains" which are tentatively assigned to secondary structure elements. PMID:6572366

  12. Reconstruction-Free Action Inference from Compressive Imagers.

    PubMed

    Kulkarni, Kuldeep; Turaga, Pavan

    2016-04-01

    Persistent surveillance from camera networks, such as at parking lots, UAVs, etc., often results in large amounts of video data, resulting in significant challenges for inference in terms of storage, communication and computation. Compressive cameras have emerged as a potential solution to deal with the data deluge issues in such applications. However, inference tasks such as action recognition require high quality features which implies reconstructing the original video data. Much work in compressive sensing (CS) theory is geared towards solving the reconstruction problem, where state-of-the-art methods are computationally intensive and provide low-quality results at high compression rates. Thus, reconstruction-free methods for inference are much desired. In this paper, we propose reconstruction-free methods for action recognition from compressive cameras at high compression ratios of 100 and above. Recognizing actions directly from CS measurements requires features which are mostly nonlinear and thus not easily applicable. This leads us to search for such properties that are preserved in compressive measurements. To this end, we propose the use of spatio-temporal smashed filters, which are compressive domain versions of pixel-domain matched filters. We conduct experiments on publicly available databases and show that one can obtain recognition rates that are comparable to the oracle method in uncompressed setup, even for high compression ratios. PMID:26353363

  13. Compressive and classical hyperspectral systems: a fundamental comparison

    NASA Astrophysics Data System (ADS)

    Shay, Adi; August, Isaac Y.; Stern, Adrian

    2015-05-01

    Hyperspectral imagery involves capturing and processing a tremendous amount of data, which sets severe system resource requirements. This has motivated the application of compressive sensing for different spectroscopic and spectroscopic imager systems. Several new compressive hyperspectral architectures have been designed to stretch the common limitations of classical systems. However, the application of the compressive sensing framework involves design of system architectures that differ significantly from the conventional ones. Since compressive sensing differs essentially from conventional sensing, it cannot be implemented for hyperspectral imaging by simply modifying one of the components of a conventional hyperspectral system, rather it requires a complete new design. In this work we present a comparison between four compressive hyperspectral architectures to conventional architectures. The compressive hyperspectral sensing compared are: Coded Aperture Snapshot Spectral Imaging (CASSI), Compressive HS Imaging by Separable Spatial And Spectral Operators (CHISSS), (Liquid-crystal Compressive spectral Imager) LiCSI and (Spectral Single-Pixel) SSP systems. Those methods are compared to conventional spatial/spectral scanning hyperspectral such as pushbroom, whiskbroom and color filter techniques. A fundamental comparison between these architectures is presented in terms of optical system volume and radiometric efficiency.

  14. Compressive sensing of sparse tensors.

    PubMed

    Friedland, Shmuel; Li, Qun; Schonfeld, Dan

    2014-10-01

    Compressive sensing (CS) has triggered an enormous research activity since its first appearance. CS exploits the signal's sparsity or compressibility in a particular domain and integrates data compression and acquisition, thus allowing exact reconstruction through relatively few nonadaptive linear measurements. While conventional CS theory relies on data representation in the form of vectors, many data types in various applications, such as color imaging, video sequences, and multisensor networks, are intrinsically represented by higher order tensors. Application of CS to higher order data representation is typically performed by conversion of the data to very long vectors that must be measured using very large sampling matrices, thus imposing a huge computational and memory burden. In this paper, we propose generalized tensor compressive sensing (GTCS)-a unified framework for CS of higher order tensors, which preserves the intrinsic structure of tensor data with reduced computational complexity at reconstruction. GTCS offers an efficient means for representation of multidimensional data by providing simultaneous acquisition and compression from all tensor modes. In addition, we propound two reconstruction procedures, a serial method and a parallelizable method. We then compare the performance of the proposed method with Kronecker compressive sensing (KCS) and multiway compressive sensing (MWCS). We demonstrate experimentally that GTCS outperforms KCS and MWCS in terms of both reconstruction accuracy (within a range of compression ratios) and processing speed. The major disadvantage of our methods (and of MWCS as well) is that the compression ratios may be worse than that offered by KCS. PMID:25137727

  15. Magnetic compression laser driving circuit

    DOEpatents

    Ball, D.G.; Birx, D.; Cook, E.G.

    1993-01-05

    A magnetic compression laser driving circuit is disclosed. The magnetic compression laser driving circuit compresses voltage pulses in the range of 1.5 microseconds at 20 kilovolts of amplitude to pulses in the range of 40 nanoseconds and 60 kilovolts of amplitude. The magnetic compression laser driving circuit includes a multi-stage magnetic switch where the last stage includes a switch having at least two turns which has larger saturated inductance with less core material so that the efficiency of the circuit and hence the laser is increased.

  16. Magnetic compression laser driving circuit

    DOEpatents

    Ball, Don G. (Livermore, CA); Birx, Dan (Brentwood, CA); Cook, Edward G. (Livermore, CA)

    1993-01-01

    A magnetic compression laser driving circuit is disclosed. The magnetic compression laser driving circuit compresses voltage pulses in the range of 1.5 microseconds at 20 Kilovolts of amplitude to pulses in the range of 40 nanoseconds and 60 Kilovolts of amplitude. The magnetic compression laser driving circuit includes a multi-stage magnetic switch where the last stage includes a switch having at least two turns which has larger saturated inductance with less core material so that the efficiency of the circuit and hence the laser is increased.

  17. Data compression for sequencing data

    PubMed Central

    2013-01-01

    Post-Sanger sequencing methods produce tons of data, and there is a general agreement that the challenge to store and process them must be addressed with data compression. In this review we first answer the question “why compression” in a quantitative manner. Then we also answer the questions “what” and “how”, by sketching the fundamental compression ideas, describing the main sequencing data types and formats, and comparing the specialized compression algorithms and tools. Finally, we go back to the question “why compression” and give other, perhaps surprising answers, demonstrating the pervasiveness of data compression techniques in computational biology. PMID:24252160

  18. Analyzing High Resolution Geoscience Data using Parallelism and Compression (Invited)

    NASA Astrophysics Data System (ADS)

    Daily, J.; Yin, J.

    2013-12-01

    Today's high-resolution climate datasets impose challenges in both storage space and I/O overhead. We explore parallel I/O and compression to address these challenges. The Parallel Analysis of GeOscience Data (pagaoda) toolkit is both an API for data-parallel analysis of geoscience climate data as well as a set of data-parallel processing tools based on this API. The API and the tools were designed first to support geodesic semi-structured NetCDF data, however they are generic enough to work with regularly gridded data as well. The command line tools are designed to mimic the NetCDF Operators but support both parallel IO and a combination of data and task parallelism. For large datasets, the single greatest performance bottleneck is IO. We describe multiple techniques we use to reduce the overhead of IO operations, namely the pseudo non-blocking interface of the parallel NetCDF library and compression. The techniques described can be applied generically to other applications using MPI-IO. We cover the current status of pagoda, compression techniques, and feature current performance information for high resolution data. Compression is promising for reducing storage space and I/O overhead. However, traditional compression algorithms, such as the LZW class compression, are designed mainly for text. These compression algorithms introduce high computation overhead and are not able to achieve high a compression ratio. We design compression algorithms specially customized for scientific data. Compared with traditional compression algorithms, our compression algorithm achieves a significantly higher compression ratio and introduces lower computation overhead. A naive architecture for incorporating compression is to first decompress data then perform computation on the decompressed data. Although this approach can reduce storage space, it hurts application performance. In our architecture, we pipeline the retrieval of compressed data from I/O devices, decompression of the data, and the computation on the decompressed data. Data decompression is overlapped with I/O operations. As a result, our architecture improves application performance by a factor close to the compression ratio for I/O bounded applications and can improve performance even for CPU bounded applications.

  19. Extreme dynamic compression with a low energy laser pulse

    NASA Astrophysics Data System (ADS)

    Armstrong, Michael; Crowhurst, Jonathan; Zaug, Joseph; Radousky, Harry

    2015-06-01

    Recently, it was shown that the energy required for laser driven dynamic compression experiments varies as the third power of the compression time, where the compression time must be larger than the equilibration time in the sample. Traditional dynamic compression experiments typically have drive times greater than 10 ns, but a wide range of materials equilibrate on substantially faster time scales, which should enable such materials to be compressed on much shorter time scales. So, for materials which equilibrate on a sub-nanosecond time scale, ultrafast dynamic compression has the potential to substantially reduce the laser energy required to obtain highly compressed states of matter. This has been demonstrated for sub-Mbar pressures with <100 ?J energy laser drive pulses, where the laser drive energy per unit density change is as much as 109 smaller than longer time scale experiments. Although these results are promising, extreme pressures (up to 10 Mbar) have not yet been observed with table-top scale laser systems. Here we present results for ultrafast laser driven shock experiments using up to 500x more drive intensity than our previous work, which, by conventional scaling, should result in dynamic pressures previously only accessible to facility scale instruments. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  20. On the characterisation of the dynamic compressive behaviour of silicon carbides subjected to isentropic compression experiments

    NASA Astrophysics Data System (ADS)

    Zinszner, Jean-Luc; Erzar, Benjamin; Forquin, Pascal; Barthélémy, François

    2015-09-01

    Ceramic materials are commonly used as protective materials particularly due to their very high hardness and compressive strength. However, the microstructure of a ceramic has a great influence on its compressive strength and on its ballistic efficiency. To study the influence of microstructural parameters on the dynamic compressive behaviour of silicon carbides, isentropic compression experiments have been performed on two silicon carbide grades using a high pulsed power generator called GEPI. Contrary to plate impact experiments, the use of the GEPI device and of the lagrangian analysis allows determining the whole loading path. The two SiC grades studied present different Hugoniot elastic limit (HEL) due to their different microstructures. For these materials, the experimental technique allowed evaluating the evolution of the equivalent stress during the dynamic compression. It has been observed that these two grades present a work hardening more or less pronounced after the HEL. The densification of the material seems to have more influence on the HEL than the grain size.

  1. Gas compression apparatus

    NASA Technical Reports Server (NTRS)

    Terp, L. S. (inventor)

    1977-01-01

    Apparatus for transferring gas from a first container to a second container of higher pressure was devised. A free-piston compressor having a driving piston and cylinder, and a smaller diameter driven piston and cylinder, comprise the apparatus. A rod member connecting the driving and driven pistons functions for mutual reciprocation in the respective cylinders. A conduit may be provided for supplying gas to the driven cylinder from the first container. Also provided is apparatus for introducing gas to the driving piston, to compress gas by the driven piston for transfer to the second higher pressure container. The system is useful in transferring spacecraft cabin oxygen into higher pressure containers for use in extravehicular activities.

  2. Compressive Network Analysis

    PubMed Central

    Jiang, Xiaoye; Yao, Yuan; Liu, Han; Guibas, Leonidas

    2014-01-01

    Modern data acquisition routinely produces massive amounts of network data. Though many methods and models have been proposed to analyze such data, the research of network data is largely disconnected with the classical theory of statistical learning and signal processing. In this paper, we present a new framework for modeling network data, which connects two seemingly different areas: network data analysis and compressed sensing. From a nonparametric perspective, we model an observed network using a large dictionary. In particular, we consider the network clique detection problem and show connections between our formulation with a new algebraic tool, namely Randon basis pursuit in homogeneous spaces. Such a connection allows us to identify rigorous recovery conditions for clique detection problems. Though this paper is mainly conceptual, we also develop practical approximation algorithms for solving empirical problems and demonstrate their usefulness on real-world datasets. PMID:25620806

  3. Population attribute compression

    DOEpatents

    White, James M. (Los Alamos, NM); Faber, Vance (Los Alamos, NM); Saltzman, Jeffrey S. (Los Alamos, NM)

    1995-01-01

    An image population having a large number of attributes is processed to form a display population with a predetermined smaller number of attributes that represent the larger number of attributes. In a particular application, the color values in an image are compressed for storage in a discrete look-up table (LUT). Color space containing the LUT color values is successively subdivided into smaller volumes until a plurality of volumes are formed, each having no more than a preselected maximum number of color values. Image pixel color values can then be rapidly placed in a volume with only a relatively few LUT values from which a nearest neighbor is selected. Image color values are assigned 8 bit pointers to their closest LUT value whereby data processing requires only the 8 bit pointer value to provide 24 bit color values from the LUT.

  4. Compressed quantum simulation

    SciTech Connect

    Kraus, B.

    2014-12-04

    Here, I summarize the results presented in B. Kraus, Phys. Rev. Lett. 107, 250503 (2011). Recently, it has been shown that certain circuits, the so-called match gate circuits, can be compressed to an exponentially smaller universal quantum computation. We use this result to demonstrate that the simulation of a 1-D Ising chain consisting of n qubits can be performed on a universal quantum computer running on only log(n) qubits. We show how the adiabatic evolution can be simulated on this exponentially smaller system and how the magnetization can be measured. Since the Ising model displays a quantum phase transition, this result implies that a quantum phase transition of a very large system can be observed with current technology.

  5. Compressed Wavefront Sensing

    PubMed Central

    Polans, James; McNabb, Ryan P.; Izatt, Joseph A.; Farsiu, Sina

    2014-01-01

    We report on an algorithm for fast wavefront sensing that incorporates sparse representation for the first time in practice. The partial derivatives of optical wavefronts were sampled sparsely with a Shack-Hartmann wavefront sensor (SHWFS) by randomly subsampling the original SHWFS data to as little as 5%. Reconstruction was performed by a sparse representation algorithm that utilized the Zernike basis. We name this method SPARZER. Experiments on real and simulated data attest to the accuracy of the proposed techniques as compared to traditional sampling and reconstruction methods. We have made the corresponding data set and software freely available online. Compressed wavefront sensing offers the potential to increase the speed of wavefront acquisition and to defray the cost of SHWFS devices. PMID:24690703

  6. Vapor compression distillation module

    NASA Technical Reports Server (NTRS)

    Nuccio, P. P.

    1975-01-01

    A Vapor Compression Distillation (VCD) module was developed and evaluated as part of a Space Station Prototype (SSP) environmental control and life support system. The VCD module includes the waste tankage, pumps, post-treatment cells, automatic controls and fault detection instrumentation. Development problems were encountered with two components: the liquid pumps, and the waste tank and quantity gauge. Peristaltic pumps were selected instead of gear pumps, and a sub-program of materials and design optimization was undertaken leading to a projected life greater than 10,000 hours of continuous operation. A bladder tank was designed and built to contain the waste liquids and deliver it to the processor. A detrimental pressure pattern imposed upon the bladder by a force-operated quantity gauge was corrected by rearranging the force application, and design goals were achieved. System testing has demonstrated that all performance goals have been fulfilled.

  7. Edge compression manifold apparatus

    DOEpatents

    Renzi, Ronald F. (Tracy, CA)

    2007-02-27

    A manifold for connecting external capillaries to the inlet and/or outlet ports of a microfluidic device for high pressure applications is provided. The fluid connector for coupling at least one fluid conduit to a corresponding port of a substrate that includes: (i) a manifold comprising one or more channels extending therethrough wherein each channel is at least partially threaded, (ii) one or more threaded ferrules each defining a bore extending therethrough with each ferrule supporting a fluid conduit wherein each ferrule is threaded into a channel of the manifold, (iii) a substrate having one or more ports on its upper surface wherein the substrate is positioned below the manifold so that the one or more ports is aligned with the one or more channels of the manifold, and (iv) device to apply an axial compressive force to the substrate to couple the one or more ports of the substrate to a corresponding proximal end of a fluid conduit.

  8. Edge compression manifold apparatus

    SciTech Connect

    Renzi, Ronald F.

    2004-12-21

    A manifold for connecting external capillaries to the inlet and/or outlet ports of a microfluidic device for high pressure applications is provided. The fluid connector for coupling at least one fluid conduit to a corresponding port of a substrate that includes: (i) a manifold comprising one or more channels extending therethrough wherein each channel is at least partially threaded, (ii) one or more threaded ferrules each defining a bore extending therethrough with each ferrule supporting a fluid conduit wherein each ferrule is threaded into a channel of the manifold, (iii) a substrate having one or more ports on its upper surface wherein the substrate is positioned below the manifold so that the one or more ports is aligned with the one or more channels of the manifold, and (iv) device to apply an axial compressive force to the substrate to couple the one or more ports of the substrate to a corresponding proximal end of a fluid conduit.

  9. MORBIDITY AND MORTALITY WEEKLY REPORT (MMWR)

    EPA Science Inventory

    The Morbidity and Mortality Weekly Report (MMWR) is used to disseminate weekly provisional data on nationally notifiable infectious diseases. These provisional data are used for program planning and evaluation, monitoring trends in incidence, and detecting disease outbreaks.

  10. Free compressible jet investigation

    NASA Astrophysics Data System (ADS)

    De Gregorio, Fabrizio

    2014-03-01

    The nozzle pressure ratio (NPR) effect on a supersonic turbulent jet was investigated. A dedicated convergent/divergent nozzle together with a flow feeding system was designed and manufactured. A nozzle Mach exit of M j = 1.5 was selected in order to obtain a convective Mach number of M c = 0.6. The flow was investigated for over-expanded, correctly expanded and under-expanded jet conditions. Mach number, total temperature and flow velocity measurements were carried out in order to characterise the jet behaviour. The inlet conditions of the jet flow were monitored in order to calculate the nozzle exit speed of sound and evaluate the mean Mach number distribution starting from the flow velocity data. A detailed analysis of the Mach results obtained by a static Pitot probe and by a particle image velocimetry measurement system was carried out. The mean flow velocity was investigated, and the axial Mach decay and the spreading rate were associated with the flow structures and with the compressibility effects. Aerodynamics of the different jet conditions was evaluated, and the shock cells structures were detected and discussed correlating the jet structure to the flow fluctuation and local turbulence. The longitudinal and radial distribution of the total temperature was investigated, and the temperature profiles were analysed and discussed. The total temperature behaviour was correlated to the turbulent phenomena and to the NPR jet conditions. Self-similarity condition was encountered and discussed for the over-expanded jet. Compressibility effects on the local turbulence, on the turbulent kinetic energy and on the Reynolds tensor were discussed.

  11. Compression and compression fatigue testing of composite laminates

    NASA Technical Reports Server (NTRS)

    Porter, T. R.

    1982-01-01

    The effects of moisture and temperature on the fatigue and fracture response of composite laminates under compression loads were investigated. The structural laminates studied were an intermediate stiffness graphite-epoxy composite (a typical angle ply laimna liminate had a typical fan blade laminate). Full and half penetration slits and impact delaminations were the defects examined. Results are presented which show the effects of moisture on the fracture and fatigue strength at room temperature, 394 K (250 F), and 422 K (300 F). Static tests results show the effects of defect size and type on the compression-fracture strength under moisture and thermal environments. The cyclic tests results compare the fatigue lives and residual compression strength under compression only and under tension-compression fatigue loading.

  12. Educators' Guide to Ally Week

    ERIC Educational Resources Information Center

    Gay, Lesbian and Straight Education Network (GLSEN), 2010

    2010-01-01

    An ally is an individual who speaks out and stands up for a person or group that is targeted and/or discriminated against. An ally works to end oppression by supporting and advocating for people who are stigmatized, or treated unfairly because of who they are. In this context, Allies are referred to as people who do not identify as LGBT (lesbian,…

  13. Data Compression Techniques for Advanced Space Transportation Systems

    NASA Technical Reports Server (NTRS)

    Bradley, William G.

    1998-01-01

    Advanced space transportation systems, including vehicle state of health systems, will produce large amounts of data which must be stored on board the vehicle and or transmitted to the ground and stored. The cost of storage or transmission of the data could be reduced if the number of bits required to represent the data is reduced by the use of data compression techniques. Most of the work done in this study was rather generic and could apply to many data compression systems, but the first application area to be considered was launch vehicle state of health telemetry systems. Both lossless and lossy compression techniques were considered in this study.

  14. Compressive sampling in computed tomography: Method and application

    NASA Astrophysics Data System (ADS)

    Hu, Zhanli; Liang, Dong; Xia, Dan; Zheng, Hairong

    2014-06-01

    Since Donoho and Candes et al. published their groundbreaking work on compressive sampling or compressive sensing (CS), CS theory has attracted a lot of attention and become a hot topic, especially in biomedical imaging. Specifically, some CS based methods have been developed to enable accurate reconstruction from sparse data in computed tomography (CT) imaging. In this paper, we will review the progress in CS based CT from aspects of three fundamental requirements of CS: sparse representation, incoherent sampling and reconstruction algorithm. In addition, some potential applications of compressive sampling in CT are introduced.

  15. Survey of Header Compression Techniques

    NASA Technical Reports Server (NTRS)

    Ishac, Joseph

    2001-01-01

    This report provides a summary of several different header compression techniques. The different techniques included are: (1) Van Jacobson's header compression (RFC 1144); (2) SCPS (Space Communications Protocol Standards) header compression (SCPS-TP, SCPS-NP); (3) Robust header compression (ROHC); and (4) The header compression techniques in RFC2507 and RFC2508. The methodology for compression and error correction for these schemes are described in the remainder of this document. All of the header compression schemes support compression over simplex links, provided that the end receiver has some means of sending data back to the sender. However, if that return path does not exist, then neither Van Jacobson's nor SCPS can be used, since both rely on TCP (Transmission Control Protocol). In addition, under link conditions of low delay and low error, all of the schemes perform as expected. However, based on the methodology of the schemes, each scheme is likely to behave differently as conditions degrade. Van Jacobson's header compression relies heavily on the TCP retransmission timer and would suffer an increase in loss propagation should the link possess a high delay and/or bit error rate (BER). The SCPS header compression scheme protects against high delay environments by avoiding delta encoding between packets. Thus, loss propagation is avoided. However, SCPS is still affected by an increased BER (bit-error-rate) since the lack of delta encoding results in larger header sizes. Next, the schemes found in RFC2507 and RFC2508 perform well for non-TCP connections in poor conditions. RFC2507 performance with TCP connections is improved by various techniques over Van Jacobson's, but still suffers a performance hit with poor link properties. Also, RFC2507 offers the ability to send TCP data without delta encoding, similar to what SCPS offers. ROHC is similar to the previous two schemes, but adds additional CRCs (cyclic redundancy check) into headers and improves compression schemes which provide better tolerances in conditions with a high BER.

  16. Bilateral hip arthroplasty: is 1-week staging the optimum strategy?

    PubMed Central

    2010-01-01

    Seventy-nine patients underwent bilateral hip arthroplasty staged either at 1 week (Group 1) or after greater intervals (as suggested by the patients, mean 44 weeks, range 16-88 weeks) (Group 2), over a five year period at one Institution. Sixty-eight patients (29 bilateral hip resurfacings and 39 total hip replacements) completed questionnaires regarding their post-operative recovery, complications and overall satisfaction with the staging of their surgery. There was no significant age or ASA grade difference between the patient groups. Complication rates in the two groups were similar and overall satisfaction rates were 84% in Group 1 (n = 32) and 89% in Group 2 (n = 36). Cumulative hospital lengths of stay were significantly longer in Group 1 patients (11.9 days vs 9.1 days)(p < 0.01); this was true for both hip resurfacing and total hip arthroplasty patients, however resurfacing patients stays were significantly shorter in both groups (p < 0.01). Postoperative pain resolved earlier in Group 1 patients at a mean of 20.9 weeks compared with a cumulative 28.9 weeks (15.8 and 13.1 weeks) for Group 2 patients (p = 0.03). The mean time to return to part-time work was 16.4 weeks for Group 1, and a cumulative 17.2 weeks (8.8 and 8.4 weeks) for Group 2. The time to return to full-time work was significantly shorter for Group 1 patients (21.0 weeks, compared with a cumulative 29.7 weeks for Group 2)(p < 0.05). The time to return to both full and part-time work was significantly shorter in total hip replacement patients with 1-week staging compared with delayed staging (22.0 vs 35.8 weeks (p = 0.02), and 13.8 vs 19.3 weeks (p = 0.03) respectively). Hip resurfacing patients in Group 2 had significantly shorter durations of postoperative pain and were able to return to part-time and full time work sooner than total hip arthroplasty patients. There was a general trend towards a faster recovery and resumption of normal activities following the second operation in Group 2 patients, compared with the first operation. Bilateral hip arthroplasty staged at a 1-week interval resulted in an earlier resolution of hip pain, and an earlier return to full-time work (particularly following total hip replacement surgery), with high levels of patient satisfaction and no increased risk in complications; however the hospital length of stay was significantly longer. The decision for the timing of staged bilateral surgery should be made in conjunction with the patient, making adjustments to accommodate their occupational needs and functional demands. PMID:21054889

  17. Understanding Infidelity: An Interview with Gerald Weeks

    ERIC Educational Resources Information Center

    Smith, Travis

    2011-01-01

    In this interview, Gerald Weeks shares his expertise on the topic of infidelity and couples counseling. Dr. Weeks defines infidelity, presents assessment strategies for treating the issue of infidelity, and discusses an intersystemic model for infidelity treatment when counseling couples. Dr. Weeks also provides insight into common mistakes made…

  18. Four-Day Week Schedule. Research Brief

    ERIC Educational Resources Information Center

    Marx, Gary E.

    2007-01-01

    What does research say about the four-day week as an alternative school schedule? More than 100 districts in at least 12 states currently use a four-day week alternative schedule. Most are located in rural areas, serve less than 1000 students, and made the move to a shorter school week with longer instructional days for financial reasons. Although…

  19. Understanding Infidelity: An Interview with Gerald Weeks

    ERIC Educational Resources Information Center

    Smith, Travis

    2011-01-01

    In this interview, Gerald Weeks shares his expertise on the topic of infidelity and couples counseling. Dr. Weeks defines infidelity, presents assessment strategies for treating the issue of infidelity, and discusses an intersystemic model for infidelity treatment when counseling couples. Dr. Weeks also provides insight into common mistakes made…

  20. Biomedical sensor design using analog compressed sensing

    NASA Astrophysics Data System (ADS)

    Balouchestani, Mohammadreza; Krishnan, Sridhar

    2015-05-01

    The main drawback of current healthcare systems is the location-specific nature of the system due to the use of fixed/wired biomedical sensors. Since biomedical sensors are usually driven by a battery, power consumption is the most important factor determining the life of a biomedical sensor. They are also restricted by size, cost, and transmission capacity. Therefore, it is important to reduce the load of sampling by merging the sampling and compression steps to reduce the storage usage, transmission times, and power consumption in order to expand the current healthcare systems to Wireless Healthcare Systems (WHSs). In this work, we present an implementation of a low-power biomedical sensor using analog Compressed Sensing (CS) framework for sparse biomedical signals that addresses both the energy and telemetry bandwidth constraints of wearable and wireless Body-Area Networks (BANs). This architecture enables continuous data acquisition and compression of biomedical signals that are suitable for a variety of diagnostic and treatment purposes. At the transmitter side, an analog-CS framework is applied at the sensing step before Analog to Digital Converter (ADC) in order to generate the compressed version of the input analog bio-signal. At the receiver side, a reconstruction algorithm based on Restricted Isometry Property (RIP) condition is applied in order to reconstruct the original bio-signals form the compressed bio-signals with high probability and enough accuracy. We examine the proposed algorithm with healthy and neuropathy surface Electromyography (sEMG) signals. The proposed algorithm achieves a good level for Average Recognition Rate (ARR) at 93% and reconstruction accuracy at 98.9%. In addition, The proposed architecture reduces total computation time from 32 to 11.5 seconds at sampling-rate=29 % of Nyquist rate, Percentage Residual Difference (PRD)=26 %, Root Mean Squared Error (RMSE)=3 %.

  1. Information optimal compressive sensing: static measurement design.

    PubMed

    Ashok, Amit; Huang, Liang-Chih; Neifeld, Mark A

    2013-05-01

    The compressive sensing paradigm exploits the inherent sparsity/compressibility of signals to reduce the number of measurements required for reliable reconstruction/recovery. In many applications additional prior information beyond signal sparsity, such as structure in sparsity, is available, and current efforts are mainly limited to exploiting that information exclusively in the signal reconstruction problem. In this work, we describe an information-theoretic framework that incorporates the additional prior information as well as appropriate measurement constraints in the design of compressive measurements. Using a Gaussian binomial mixture prior we design and analyze the performance of optimized projections relative to random projections under two specific design constraints and different operating measurement signal-to-noise ratio (SNR) regimes. We find that the information-optimized designs yield significant, in some cases nearly an order of magnitude, improvements in the reconstruction performance with respect to the random projections. These improvements are especially notable in the low measurement SNR regime where the energy-efficient design of optimized projections is most advantageous. In such cases, the optimized projection design departs significantly from random projections in terms of their incoherence with the representation basis. In fact, we find that the maximizing incoherence of projections with the representation basis is not necessarily optimal in the presence of additional prior information and finite measurement noise/error. We also apply the information-optimized projections to the compressive image formation problem for natural scenes, and the improved visual quality of reconstructed images with respect to random projections and other compressive measurement design affirms the overall effectiveness of the information-theoretic design framework. PMID:23695314

  2. Tissue engineering of cartilage using a mechanobioreactor exerting simultaneous mechanical shear and compression to simulate the rolling action of articular joints.

    PubMed

    Shahin, Kifah; Doran, Pauline M

    2012-04-01

    The effect of dynamic mechanical shear and compression on the synthesis of human tissue-engineered cartilage was investigated using a mechanobioreactor capable of simulating the rolling action of articular joints in a mixed fluid environment. Human chondrocytes seeded into polyglycolic acid (PGA) mesh or PGA-alginate scaffolds were precultured in shaking T-flasks or recirculation perfusion bioreactors for 2.5 or 4 weeks prior to mechanical stimulation in the mechanobioreactor. Constructs were subjected to intermittent unconfined shear and compressive loading at a frequency of 0.05?Hz using a peak-to-peak compressive strain amplitude of 2.2% superimposed on a static axial compressive strain of 6.5%. The mechanical treatment was carried out for up to 2.5 weeks using a loading regime of 10?min duration each day with the direction of the shear forces reversed after 5?min and release of all loading at the end of the daily treatment period. Compared with shaking T-flasks and mechanobioreactor control cultures without loading, mechanical treatment improved the amount and quality of cartilage produced. On a per cell basis, synthesis of both major structural components of cartilage, glycosaminoglycan (GAG) and collagen type II, was enhanced substantially by up to 5.3- and 10-fold, respectively, depending on the scaffold type and seeding cell density. Levels of collagen type II as a percentage of total collagen were also increased after mechanical treatment by up to 3.4-fold in PGA constructs. Mechanical treatment had a less pronounced effect on the composition of constructs precultured in perfusion bioreactors compared with perfusion culture controls. This work demonstrates that the quality of tissue-engineered cartilage can be enhanced significantly by application of simultaneous dynamic mechanical shear and compression, with the greatest benefits evident for synthesis of collagen type II. PMID:22095592

  3. [Digital watermarking for electroencephalogram compression].

    PubMed

    Liu, Jianping; Yu, Xiaolin; Zhang, Chong; Zheng, Chongxun

    2005-08-01

    In this paper, digital watermarking and EEG compression are introduced firstly, and then a number of digital watermarking methods are explored to resolve the problem of integrality and authenticity in EEG compression. At last, the current state of this technique inside and outside country is summarized and future endeavors are discussed. PMID:16156291

  4. "Noiseless" Data-Compression Algorithm

    NASA Technical Reports Server (NTRS)

    Rice, R. F.; Lee, J. J.

    1986-01-01

    Gamma-ray spectrometer data compressed to enable more frequent sampling. Proposed data-compression algorithm efficiently represents gamma-ray spectrometer spectra at any spectrum collection interval from 5 seconds to 5 minutes. Data representations "noiseless" (Data exactly constructed). Techniques useful in designing datacompression algorithms for other spectral instruments, which have varying data-rate requirements.

  5. Compression Shocks of Detached Flow

    NASA Technical Reports Server (NTRS)

    Eggink

    1947-01-01

    It is known that compression shocks which lead from supersonic to subsonic velocity cause the flow to separate on impact on a rigid wall. Such shocks appear at bodies with circular symmetry or wing profiles on locally exceeding sonic velocity, and in Laval nozzles with too high a back pressure. The form of the compression shocks observed therein is investigated.

  6. Streaming Compression of Hexahedral Meshes

    SciTech Connect

    Isenburg, M; Courbet, C

    2010-02-03

    We describe a method for streaming compression of hexahedral meshes. Given an interleaved stream of vertices and hexahedral our coder incrementally compresses the mesh in the presented order. Our coder is extremely memory efficient when the input stream documents when vertices are referenced for the last time (i.e. when it contains topological finalization tags). Our coder then continuously releases and reuses data structures that no longer contribute to compressing the remainder of the stream. This means in practice that our coder has only a small fraction of the whole mesh in memory at any time. We can therefore compress very large meshes - even meshes that do not file in memory. Compared to traditional, non-streaming approaches that load the entire mesh and globally reorder it during compression, our algorithm trades a less compact compressed representation for significant gains in speed, memory, and I/O efficiency. For example, on the 456k hexahedra 'blade' mesh, our coder is twice as fast and uses 88 times less memory (only 3.1 MB) with the compressed file increasing about 3% in size. We also present the first scheme for predictive compression of properties associated with hexahedral cells.

  7. Application specific compression : final report.

    SciTech Connect

    Melgaard, David Kennett; Byrne, Raymond Harry; Myers, Daniel S.; Harrison, Carol D.; Lee, David S.; Lewis, Phillip J.; Carlson, Jeffrey J.

    2008-12-01

    With the continuing development of more capable data gathering sensors, comes an increased demand on the bandwidth for transmitting larger quantities of data. To help counteract that trend, a study was undertaken to determine appropriate lossy data compression strategies for minimizing their impact on target detection and characterization. The survey of current compression techniques led us to the conclusion that wavelet compression was well suited for this purpose. Wavelet analysis essentially applies a low-pass and high-pass filter to the data, converting the data into the related coefficients that maintain spatial information as well as frequency information. Wavelet compression is achieved by zeroing the coefficients that pertain to the noise in the signal, i.e. the high frequency, low amplitude portion. This approach is well suited for our goal because it reduces the noise in the signal with only minimal impact on the larger, lower frequency target signatures. The resulting coefficients can then be encoded using lossless techniques with higher compression levels because of the lower entropy and significant number of zeros. No significant signal degradation or difficulties in target characterization or detection were observed or measured when wavelet compression was applied to simulated and real data, even when over 80% of the coefficients were zeroed. While the exact level of compression will be data set dependent, for the data sets we studied, compression factors over 10 were found to be satisfactory where conventional lossless techniques achieved levels of less than 3.

  8. Pressure Oscillations in Adiabatic Compression

    ERIC Educational Resources Information Center

    Stout, Roland

    2011-01-01

    After finding Moloney and McGarvey's modified adiabatic compression apparatus, I decided to insert this experiment into my physical chemistry laboratory at the last minute, replacing a problematic experiment. With insufficient time to build the apparatus, we placed a bottle between two thick textbooks and compressed it with a third textbook forced…

  9. Pressure Oscillations in Adiabatic Compression

    ERIC Educational Resources Information Center

    Stout, Roland

    2011-01-01

    After finding Moloney and McGarvey's modified adiabatic compression apparatus, I decided to insert this experiment into my physical chemistry laboratory at the last minute, replacing a problematic experiment. With insufficient time to build the apparatus, we placed a bottle between two thick textbooks and compressed it with a third textbook forced…

  10. Lossless compression algorithm for multispectral imagers

    NASA Astrophysics Data System (ADS)

    Gladkova, Irina; Grossberg, Michael; Gottipati, Srikanth

    2008-08-01

    Multispectral imaging is becoming an increasingly important tool for monitoring the earth and its environment from space borne and airborne platforms. Multispectral imaging data consists of visible and IR measurements from a scene across space and spectrum. Growing data rates resulting from faster scanning and finer spatial and spectral resolution makes compression an increasingly critical tool to reduce data volume for transmission and archiving. Research for NOAA NESDIS has been directed to finding for the characteristics of satellite atmospheric Earth science Imager sensor data what level of Lossless compression ratio can be obtained as well as appropriate types of mathematics and approaches that can lead to approaching this data's entropy level. Conventional lossless do not achieve the theoretical limits for lossless compression on imager data as estimated from the Shannon entropy. In a previous paper, the authors introduce a lossless compression algorithm developed for MODIS as a proxy for future NOAA-NESDIS satellite based Earth science multispectral imagers such as GOES-R. The algorithm is based on capturing spectral correlations using spectral prediction, and spatial correlations with a linear transform encoder. In decompression, the algorithm uses a statistically computed look up table to iteratively predict each channel from a channel decompressed in the previous iteration. In this paper we present a new approach which fundamentally differs from our prior work. In this new approach, instead of having a single predictor for each pair of bands we introduce a piecewise spatially varying predictor which significantly improves the compression results. Our new algorithm also now optimizes the sequence of channels we use for prediction. Our results are evaluated by comparison with a state of the art wavelet based image compression scheme, Jpeg2000. We present results on the 14 channel subset of the MODIS imager, which serves as a proxy for the GOES-R imager. We will also show results of the algorithm for on NOAA AVHRR data and data from SEVIRI. The algorithm is designed to be adapted to the wide range of multispectral imagers and should facilitate distribution of data throughout globally. This compression research is managed by Roger Heymann, PE of OSD NOAA NESDIS Engineering, in collaboration with the NOAA NESDIS STAR Research Office through Mitch Goldberg, Tim Schmit, Walter Wolf.

  11. Digital compression algorithms for HDTV transmission

    NASA Technical Reports Server (NTRS)

    Adkins, Kenneth C.; Shalkhauser, Mary JO; Bibyk, Steven B.

    1990-01-01

    Digital compression of video images is a possible avenue for high definition television (HDTV) transmission. Compression needs to be optimized while picture quality remains high. Two techniques for compression the digital images are explained and comparisons are drawn between the human vision system and artificial compression techniques. Suggestions for improving compression algorithms through the use of neural and analog circuitry are given.

  12. Compression of digitized map images

    NASA Astrophysics Data System (ADS)

    Southard, David A.

    1992-10-01

    An efficient way to store and retrieve digitized chart images using a lossy vector quantization (VQ) compression technique is presented. A VQ codebook is located using the fast pairwise nearest neighbor (PNN) clustering algorithm. A k-d tree data structure is used for efficient image compression. Some unique features of this approach are that compressed files use a predictable amount of storage, and can be decompressed quickly for display on equipment ranging from portable personal computers to advanced graphics workstations. The method also applies to panchromatic and multispectral satellite imagery. In this application, digitized chart images with compression ratios of 24:1 exhibited good quality. In certain applications, even higher compression ratios are feasible.

  13. Vortex Stabilized Compressed Fusion Grade Plasma

    NASA Astrophysics Data System (ADS)

    Hershcovitch, Ady

    2015-03-01

    Inertial confinement fusion schemes comprise of highly compressed dense plasmas. Some involve short pulses of powerful beams (lasers, particles) applied to solid pellets, while others utilize plasma focus to obtain dense pinch plasmas. Although compression factor >1000 has been achieved for starting pressures in the Torr range, the latter is limited by instabilities for initial gas density above 10 Torr. One alternative approach could be shooting electron beams through very dense, atmospheric pressure, vortex stabilized plasma. Large azimuthal magnetic generated by an electron beam can compress and heat the plasma to fusion viable parameters. This configuration is stable against sausage, kink, or beam - plasma instabilities. Based on experimental evidence beam propagation through the plasma is not be an issue. A second possibility is to tangentially squeeze a quasi-neutral plasma focus flow by a surrounding gas vortex. Based on currently available electron beams, the first scheme viability as an electrical power generating reactor does not seem to be promising. But using a plasma cathode electron beam that was developed a while ago, for which DOE has a patent U.S. Patent 4,942,339, could result in net generation of electricity. Calculations will be presented. Work supported by Work supported under Contract No. DE-AC02-98CH1-886 with the US Department of Energy.

  14. Approximation and compression with sparse orthonormal transforms.

    PubMed

    Sezer, Osman Gokhan; Guleryuz, Onur G; Altunbasak, Yucel

    2015-08-01

    We propose a new transform design method that targets the generation of compression-optimized transforms for next-generation multimedia applications. The fundamental idea behind transform compression is to exploit regularity within signals such that redundancy is minimized subject to a fidelity cost. Multimedia signals, in particular images and video, are well known to contain a diverse set of localized structures, leading to many different types of regularity and to nonstationary signal statistics. The proposed method designs sparse orthonormal transforms (SOTs) that automatically exploit regularity over different signal structures and provides an adaptation method that determines the best representation over localized regions. Unlike earlier work that is motivated by linear approximation constructs and model-based designs that are limited to specific types of signal regularity, our work uses general nonlinear approximation ideas and a data-driven setup to significantly broaden its reach. We show that our SOT designs provide a safe and principled extension of the Karhunen-Loeve transform (KLT) by reducing to the KLT on Gaussian processes and by automatically exploiting non-Gaussian statistics to significantly improve over the KLT on more general processes. We provide an algebraic optimization framework that generates optimized designs for any desired transform structure (multiresolution, block, lapped, and so on) with significantly better n -term approximation performance. For each structure, we propose a new prototype codec and test over a database of images. Simulation results show consistent increase in compression and approximation performance compared with conventional methods. PMID:25823033

  15. Chronic sciatic nerve compression induces fibrosis in dorsal root ganglia

    PubMed Central

    LI, QINWEN; CHEN, JIANGHAI; CHEN, YANHUA; CONG, XIAOBIN; CHEN, ZHENBING

    2016-01-01

    In the present study, pathological alterations in neurons of the dorsal root ganglia (DRG) were investigated in a rat model of chronic sciatic nerve compression. The rat model of chronic sciatic nerve compression was established by placing a 1 cm Silastic tube around the right sciatic nerve. Histological examination was performed via Masson's trichrome staining. DRG injury was assessed using Fluoro Ruby (FR) or Fluoro Gold (FG). The expression levels of target genes were examined using reverse transcription-quantitative polymerase chain reaction, western blot and immunohistochemical analyses. At 3 weeks post-compression, collagen fiber accumulation was observed in the ipsilateral area and, at 8 weeks, excessive collagen formation with muscle atrophy was observed. The collagen volume fraction gradually and significantly increased following sciatic nerve compression. In the model rats, the numbers of FR-labeled DRG neurons were significantly higher, relative to the sham-operated group, however, the numbers of FG-labeled neurons were similar. In the ipsilateral DRG neurons of the model group, the levels of transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF) were elevated and, surrounding the neurons, the levels of collagen type I were increased, compared with those in the contralateral DRG. In the ipsilateral DRG, chronic nerve compression was associated with significantly higher levels of phosphorylated (p)-extracellular signal-regulated kinase 1/2, and significantly lower levels of p-c-Jun N-terminal kinase and p-p38, compared with those in the contralateral DRGs. Chronic sciatic nerve compression likely induced DRG pathology by upregulating the expression levels of TGF-β1, CTGF and collagen type I, with involvement of the mitogen-activated protein kinase signaling pathway. PMID:26820076

  16. Detecting double compression of audio signal

    NASA Astrophysics Data System (ADS)

    Yang, Rui; Shi, Yun Q.; Huang, Jiwu

    2010-01-01

    MP3 is the most popular audio format nowadays in our daily life, for example music downloaded from the Internet and file saved in the digital recorder are often in MP3 format. However, low bitrate MP3s are often transcoded to high bitrate since high bitrate ones are of high commercial value. Also audio recording in digital recorder can be doctored easily by pervasive audio editing software. This paper presents two methods for the detection of double MP3 compression. The methods are essential for finding out fake-quality MP3 and audio forensics. The proposed methods use support vector machine classifiers with feature vectors formed by the distributions of the first digits of the quantized MDCT (modified discrete cosine transform) coefficients. Extensive experiments demonstrate the effectiveness of the proposed methods. To the best of our knowledge, this piece of work is the first one to detect double compression of audio signal.

  17. Compressed-domain video parsing using energy histograms of the lower-frequency DCT coefficients

    NASA Astrophysics Data System (ADS)

    Bao, Oliver K.; Lay, Jose A.; Guan, Ling

    1999-12-01

    As an increasing amount of audio-visual data is stored, distribute, and used in the compressed form, compressed- domain techniques will be favorable. However, as conventional features may not be accessible in the compressed domain, exploration of new compressed domain features will become mandatory. Studies have shown that the DC coefficients of a DCT-compressed video can be used to detect shot transitions for relatively simple video sequences.In this work, the use of the energy histogram of the lower frequency DCT coefficients as features for video parsing was examined. The experimental results show an improvement over those obtained by the DC coefficients alone.

  18. Compressive Sensing for Quantum Imaging

    NASA Astrophysics Data System (ADS)

    Howland, Gregory A.

    This thesis describes the application of compressive sensing to several challenging problems in quantum imaging with practical and fundamental implications. Compressive sensing is a measurement technique that compresses a signal during measurement such that it can be dramatically undersampled. Compressive sensing has been shown to be an extremely efficient measurement technique for imaging, particularly when detector arrays are not available. The thesis first reviews compressive sensing through the lens of quantum imaging and quantum measurement. Four important applications and their corresponding experiments are then described in detail. The first application is a compressive sensing, photon-counting lidar system. A novel depth mapping technique that uses standard, linear compressive sensing is described. Depth maps up to 256 x 256 pixel transverse resolution are recovered with depth resolution less than 2.54 cm. The first three-dimensional, photon counting video is recorded at 32 x 32 pixel resolution and 14 frames-per-second. The second application is the use of compressive sensing for complementary imaging---simultaneously imaging the transverse-position and transverse-momentum distributions of optical photons. This is accomplished by taking random, partial projections of position followed by imaging the momentum distribution on a cooled CCD camera. The projections are shown to not significantly perturb the photons' momenta while allowing high resolution position images to be reconstructed using compressive sensing. A variety of objects and their diffraction patterns are imaged including the double slit, triple slit, alphanumeric characters, and the University of Rochester logo. The third application is the use of compressive sensing to characterize spatial entanglement of photon pairs produced by spontaneous parametric downconversion. The technique gives a theoretical speedup N2/log N for N-dimensional entanglement over the standard raster scanning technique. Entanglement imaging is demonstrated at 1024 dimensions-per-photon with channel capacities exceeding 8.4 bits-per-photon. In practice, the measurement time is reduced from 310 days for the standard technique to 8 hours for the compressive technique. An entropic steering inequality is violated to witness entanglement. The final application is a compressive wavefront sensor that unites compressive sensing with weak measurement. We show how a twisted-nematic spatial light modulator can be be used to weakly couple an optical field's position and polarization degrees of freedom. The complex nature of the weak value is used to directly measure random projections of the real and imaginary parts of the optical field, where polarization serves as an ancillary meter. We obtain 256 x 256 pixel wavefronts from only 10,000 random projections. Photon-counting detectors provide sub-picowatt sensitivity.

  19. Aerosol and cloud relations and weekly cycles over Central Europe

    NASA Astrophysics Data System (ADS)

    Kourtidis, K.; Georgoulias, A.; Alexandri, G.

    2012-04-01

    In this work, the aerosol and cloud relationships and weekly cycle patterns over Central Europe are examined using level-2 aerosol data from the TERRA MODIS satellite instrument to compile a decadal (2000-2010) 0.1 x 0.1 degree resolution gridded dataset as well as and total cloud cover (TCC) TERRA MODIS data and coarser resolution ISCCP TCC data. Aerosols and TCC were found to be positively correlated for all seasons, the slope of the correlation being slightly higher for low AOD values. A co-examination of AOD, TCC and NCAR/NCEP sea level pressure shows that the positive AOD-TCC correlation holds separately in all pressure bins, thus indicating that the correlation is not a synoptic artefact. A study of the weekly cycle of AOD shows that the main part of the positive (i.e. with midweek peak) weekly cycle plume extends over the central part of Central Europe, with the weekly cycle index (WCI) levels gradually decreasing until the weekly cycle becomes negative (i.e. with weekend peak) when moving away. No clear connection between the WCI patterns and topography was found while there is an apparent correlation between positive weekly cycles in summer and population density. A clear Monday minimum appears over regions with high positive WCI. Monday shifts to Tuesday when moving to the East, indicating aerosol transport from the dominating westerly wind flow. The WCI values and the average percent departures (APDs) for the day of weekly maximum and minimum were examined for 22 selected stations from previous ground-based weekly cycle studies. The weekly cycle is positive and statistically significant for only a few stations situated in France, Germany, Czech Republic and Belgium. A comparison with 1 x 1 degree level-3 MODIS TERRA data shows that in most cases level-3 data can give an indication of the local aerosol weekly cycle strength and phase. The satellite derived day of the weekly maximum and minimum is, generally, in line with results from ground-based studies. The seasonal examination of the WCI patterns show that the positive signal over Central Europe is strongest during summer. More interestingly, the amplitude and phasing of the AOD weekly variability agrees with the TCC one, both for MODIS and ISCCP.

  20. Compression relief engine brake

    SciTech Connect

    Meneely, V.A.

    1987-10-06

    A compression relief brake is described for four cycle internal-combustion engines, comprising: a pressurized oil supply; means for selectively pressurizing a hydraulic circuit with oil from the oil supply; a master piston and cylinder communicating with a slave piston and cylinder via the hydraulic circuit; an engine exhaust valve mechanically coupled to the engine and timed to open during the exhaust cycle of the engine the exhaust valve coupled to the slave piston. The exhaust valve is spring-based in a closed state to contact a valve seat; a sleeve frictionally and slidably disposed within a cavity defined by the slave piston which cavity communicates with the hydraulic circuit. When the hydraulic circuit is selectively pressurized and the engine is operating the sleeve entraps an incompressible volume of oil within the cavity to generate a displacement of the slave piston within the slave cylinder, whereby a first gap is maintained between the exhaust valve and its associated seat; and means for reciprocally activating the master piston for increasing the pressure within the previously pressurized hydraulic circuit during at least a portion of the expansion cycle of the engine whereby a second gap is reciprocally maintained between the exhaust valve and its associated seat.

  1. The Romance Days of the Week: An Underlying Cohesiveness.

    ERIC Educational Resources Information Center

    Holman, Robyn A.

    1994-01-01

    Reexamines the work of earlier scholars on the circumstances accompanying the changes in the names of the days of the week. Syntactic changes as well as the Church's struggle to eradicate the names of the pagan divinities played a great role in effecting these changes. Dual designations, full forms, and condensed ones existed side by side in some…

  2. 75 FR 52211 - Minority Enterprise Development Week, 2010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-25

    ... the two hundred and thirty-fifth. (Presidential Sig.) [FR Doc. 2010-21294 Filed 8-24-10; 8:45 am... Development Week, 2010 By the President of the United States of America A Proclamation Since our Nation's... tireless work ethic has defined the character of our country. During Minority Enterprise Development...

  3. Breaking the Mold. An "Education Week" Occasional Series.

    ERIC Educational Resources Information Center

    Education Week, 1995

    1995-01-01

    Eight articles, published in various issues of "Education Week" starting in March 1994 and ending July 1995, track the work of eight educational reform design teams: (1) "Back to the Future" (Lynn Olson)--the virtues and values of the past in a modern context; (2) "A Welcome Change" (Ann Bradley)--instruction school management, and social services…

  4. Best compression: Reciprocating or rotary?

    SciTech Connect

    Cahill, C.

    1997-07-01

    A compressor is a device used to increase the pressure of a compressible fluid. The inlet pressure can vary from a deep vacuum to a high positive pressure. The discharge pressure can range from subatmospheric levels to tens of thousands of pounds per square inch. Compressors come in numerous forms, but for oilfield applications there are two primary types, reciprocating and rotary. Both reciprocating and rotary compressors are grouped in the intermittent mode of compression. Intermittent is cyclic in nature, in that a specific quantity of gas is ingested by the compressor, acted upon and discharged before the cycle is repeated. Reciprocating compression is the most common form of compression used for oilfield applications. Rotary screw compressors have a long history but are relative newcomers to oilfield applications. The rotary screw compressor-technically a helical rotor compressor-dates back to 1878. That was when the first rotary screw was manufactured for the purpose of compressing air. Today thousands of rotary screw compression packages are being used throughout the world to compress natural gas.

  5. Lossless compression of pseudocolor images

    NASA Astrophysics Data System (ADS)

    Arnavut, Ziya; Leavitt, David; Abdulazizoglu, Meral

    1998-10-01

    In a pseudo-color (color-mapped) image pixel values represent indices that point to color values in a look-up table. Well-known linear predictive schemes, such as JPEG and CALIC, perform poorly when used with pseudo-color images, while universal compressors, such as Gzip, Pkzip and Compress, yield better compression gain. Recently, Burrows and Wheeler introduced the Block Sorting Lossless Data Compression Algorithm (BWA). The BWA algorithm received considerable attention. It achieves compression rates as good as context-based methods, such as PPM, but at execution speeds closer to Ziv-Lempel techniques. The BWA algorithm is mainly composed of a block-sorting transformation which is known as Burrows-Wheeler Transformation (BWT), followed by Move-To-Front coding. In this paper, we introduce a new block transformation, Linear Order Transformation (LOT). We delineate its relationship to BWT and show that LOT is faster than BWT transformation. We then show that when MTF coder is employed after the LOT, the compression gain obtained is better than the well-known compression techniques, such as GIF, JPEG, CALLIC, Gzip, LZW (Unix Compress) and the BWA for pseudo-color images.

  6. Advances in compressible turbulent mixing

    SciTech Connect

    Dannevik, W.P.; Buckingham, A.C.; Leith, C.E.

    1992-01-01

    This volume includes some recent additions to original material prepared for the Princeton International Workshop on the Physics of Compressible Turbulent Mixing, held in 1988. Workshop participants were asked to emphasize the physics of the compressible mixing process rather than measurement techniques or computational methods. Actual experimental results and their meaning were given precedence over discussions of new diagnostic developments. Theoretical interpretations and understanding were stressed rather than the exposition of new analytical model developments or advances in numerical procedures. By design, compressibility influences on turbulent mixing were discussed--almost exclusively--from the perspective of supersonic flow field studies. The papers are arranged in three topical categories: Foundations, Vortical Domination, and Strongly Coupled Compressibility. The Foundations category is a collection of seminal studies that connect current study in compressible turbulent mixing with compressible, high-speed turbulent flow research that almost vanished about two decades ago. A number of contributions are included on flow instability initiation, evolution, and transition between the states of unstable flow onset through those descriptive of fully developed turbulence. The Vortical Domination category includes theoretical and experimental studies of coherent structures, vortex pairing, vortex-dynamics-influenced pressure focusing. In the Strongly Coupled Compressibility category the organizers included the high-speed turbulent flow investigations in which the interaction of shock waves could be considered an important source for production of new turbulence or for the enhancement of pre-existing turbulence. Individual papers are processed separately.

  7. Data compression applied to HHVT

    NASA Technical Reports Server (NTRS)

    Thompson, William K.

    1990-01-01

    A task order was written by the High Resolution, High Frame Rate Video Technology (HHVT) project engineers to study data compression techniques that could be applied to the HHVT system. Specifically, the goals of the HHVT data compression study are to accomplish the following: (1) Determine the downlink capabilities of the Space Shuttle and Space Station Freedom to support HHVT data (i.e., determine the maximum data rates and link availability); (2) Determine current and projected capabilities of high speed storage media to support HHVT data by determining their maximum data acquisition/transmission rates and volumes; (3) Identify which experiment in the HHVT Users' Requirement data base need data compression, based on the experiments' imaging requirements; (4) Select the best data compression technique for each of these users by identifying a technique that provides compression but minimizes distortion; and (5) Investigate state-of-the-art technologies for possible implementation of selected data compression techniques. Data compression will be needed because of the high data rates and larger volumes of data that will result from the use of digitized video onboard the Space Shuttle and Space Station Freedom.

  8. The OMV Data Compression System Science Data Compression Workshop

    NASA Technical Reports Server (NTRS)

    Lewis, Garton H., Jr.

    1989-01-01

    The Video Compression Unit (VCU), Video Reconstruction Unit (VRU), theory and algorithms for implementation of Orbital Maneuvering Vehicle (OMV) source coding, docking mode, channel coding, error containment, and video tape preprocessed space imagery are presented in viewgraph format.

  9. Vertebral Compression Exacerbates Osteoporotic Pain in an Ovariectomy-Induced Osteoporosis Rat Model.

    PubMed

    Suzuki, Miyako; Orita, Sumihisa; Miyagi, Masayuki; Ishikawa, Tetsuhiro; Kamoda, Hiroto; Eguchi, Yawara; Arai, Gen; Yamauchi, Kazuyo; Sakuma, Yoshihiro; Oikawa, Yasuhiro; Kubota, Go; Inage, Kazuhide; Sainoh, Takeshi; Kawarai, Yuya; Yoshino, Kensuke; Ozawa, Tomoyuki; Aoki, Yasuchika; Toyone, Tomoaki; Takahashi, Kazuhisa; Kawakami, Mamoru; Ohtori, Seiji; Inoue, Gen

    2013-09-10

    Study Design. Basic pain study using osteoporotic rodent models.Objective. To examine alterations in distribution of pain-related neuropeptides following compressive force on osteoporotic vertebrae and their chronic pain-related properties.Summary of Background Data. We previously reported significantly increased production of calcitonin gene-related peptide (CGRP), a marker of inflammatory pain, in the dorsal root ganglia (DRG) of vertebrae in osteoporosis-model ovariectomized (OVX) rats. Here, we hypothesized that longitudinal compressive force on vertebrae can affect osteoporotic pain properties, which has not been examined yet.Methods. OVX rats were used as the osteoporosis model. Female Sprague Dawley rats were prepared and Fluoro-Gold (FG) neurotracer was applied to the periosteal surface of the Co5 vertebra. After FG-labeling, the animals were divided into 4 groups: Control, Control + compression, OVX, and OVX + compression. The Control groups were not ovariectomized. In the compression groups, K-wires were stabbed transversely through Co4 and Co6 with Co5 compressed longitudinally by rubber bands bridged between the two. One, 2, 4, and 8 weeks after surgery, bilateral S1 to S3 DRGs were excised for immunofluorescence assays. Expression of CGRP and activating transcription factor 3 (ATF-3), a marker of neuronal injury, were compared among the 4 groups.Results. Sustained upregulation of CGRP in DRG neurons was observed following compression of the Co5 vertebra, and Co5 compression caused significant increase in CGRP production in DRG neurons, while a greater level of ATF-3 upregulation was observed in DRGs in OVX rats following dynamic vertebral compression 8 weeks after surgery, implying potential neuropathic pain.Conclusion: There was sustained upregulation of CGRP and ATF3 in DRGs in osteoporotic model rats compared with controls, and levels were further enhanced by dynamic vertebral compression. These findings imply that dynamic compression stress on vertebrae can exacerbate osteoporotic pain by inducing both inflammatory and neuropathic pain mediators. PMID:24026152

  10. Designing experiments through compressed sensing.

    SciTech Connect

    Young, Joseph G.; Ridzal, Denis

    2013-06-01

    In the following paper, we discuss how to design an ensemble of experiments through the use of compressed sensing. Specifically, we show how to conduct a small number of physical experiments and then use compressed sensing to reconstruct a larger set of data. In order to accomplish this, we organize our results into four sections. We begin by extending the theory of compressed sensing to a finite product of Hilbert spaces. Then, we show how these results apply to experiment design. Next, we develop an efficient reconstruction algorithm that allows us to reconstruct experimental data projected onto a finite element basis. Finally, we verify our approach with two computational experiments.

  11. Non-observation RINEX compression

    NASA Astrophysics Data System (ADS)

    Bezručka, Juraj

    2013-12-01

    RINEX format is a result of an effort to standardize exchanging GNSS related data in human readable receiver independent format. Besides observation data, RINEX is also de facto standard for exchanging navigation message or meteorological data. The paper describes simple compression methods for navigation messages and meteorological data files. Both formats have their specific features, therefore different methods were used. Followed by standard compression the algorithms reduce the file size by more than 20 percent compared to standard compression. Thanks to the properties of weather and regular parameter observations it allows to reduce the file size of meteorological RINEX to a mere fraction of its original size.

  12. Studies on image compression and image reconstruction

    NASA Technical Reports Server (NTRS)

    Sayood, Khalid; Nori, Sekhar; Araj, A.

    1994-01-01

    During this six month period our works concentrated on three, somewhat different areas. We looked at and developed a number of error concealment schemes for use in a variety of video coding environments. This work is described in an accompanying (draft) Masters thesis. In the thesis we describe application of this techniques to the MPEG video coding scheme. We felt that the unique frame ordering approach used in the MPEG scheme would be a challenge to any error concealment/error recovery technique. We continued with our work in the vector quantization area. We have also developed a new type of vector quantizer, which we call a scan predictive vector quantization. The scan predictive VQ was tested on data processed at Goddard to approximate Landsat 7 HRMSI resolution and compared favorably with existing VQ techniques. A paper describing this work is included. The third area is concerned more with reconstruction than compression. While there is a variety of efficient lossless image compression schemes, they all have a common property that they use past data to encode future data. This is done either via taking differences, context modeling, or by building dictionaries. When encoding large images, this common property becomes a common flaw. When the user wishes to decode just a portion of the image, the requirement that the past history be available forces the decoding of a significantly larger portion of the image than desired by the user. Even with intelligent partitioning of the image dataset, the number of pixels decoded may be four times the number of pixels requested. We have developed an adaptive scanning strategy which can be used with any lossless compression scheme and which lowers the additional number of pixels to be decoded to about 7 percent of the number of pixels requested! A paper describing these results is included.

  13. Low-Complexity Lossless and Near-Lossless Data Compression Technique for Multispectral Imagery

    NASA Technical Reports Server (NTRS)

    Xie, Hua; Klimesh, Matthew A.

    2009-01-01

    This work extends the lossless data compression technique described in Fast Lossless Compression of Multispectral- Image Data, (NPO-42517) NASA Tech Briefs, Vol. 30, No. 8 (August 2006), page 26. The original technique was extended to include a near-lossless compression option, allowing substantially smaller compressed file sizes when a small amount of distortion can be tolerated. Near-lossless compression is obtained by including a quantization step prior to encoding of prediction residuals. The original technique uses lossless predictive compression and is designed for use on multispectral imagery. A lossless predictive data compression algorithm compresses a digitized signal one sample at a time as follows: First, a sample value is predicted from previously encoded samples. The difference between the actual sample value and the prediction is called the prediction residual. The prediction residual is encoded into the compressed file. The decompressor can form the same predicted sample and can decode the prediction residual from the compressed file, and so can reconstruct the original sample. A lossless predictive compression algorithm can generally be converted to a near-lossless compression algorithm by quantizing the prediction residuals prior to encoding them. In this case, since the reconstructed sample values will not be identical to the original sample values, the encoder must determine the values that will be reconstructed and use these values for predicting later sample values. The technique described here uses this method, starting with the original technique, to allow near-lossless compression. The extension to allow near-lossless compression adds the ability to achieve much more compression when small amounts of distortion are tolerable, while retaining the low complexity and good overall compression effectiveness of the original algorithm.

  14. Correlation estimation and performance optimization for distributed image compression

    NASA Astrophysics Data System (ADS)

    He, Zhihai; Cao, Lei; Cheng, Hui

    2006-01-01

    Correlation estimation plays a critical role in resource allocation and rate control for distributed data compression. A Wyner-Ziv encoder for distributed image compression is often considered as a lossy source encoder followed by a lossless Slepian-Wolf encoder. The source encoder consists of spatial transform, quantization, and bit plane extraction. In this work, we find that Gray code, which has been extensively used in digital modulation, is able to significantly improve the correlation between the source data and its side information. Theoretically, we analyze the behavior of Gray code within the context of distributed image compression. Using this theoretical model, we are able to efficiently allocate the bit budget and determine the code rate of the Slepian-Wolf encoder. Our experimental results demonstrate that the Gray code, coupled with accurate correlation estimation and rate control, significantly improves the picture quality, by up to 4 dB, over the existing methods for distributed image compression.

  15. CCD noise influence on JPEG2000 compression of astronomical images

    NASA Astrophysics Data System (ADS)

    Páta, Petr

    2011-09-01

    Compression of astronomical images is still current task. In most applications, lossless approaches are used that do no damage to the compressed data. These algorithms, however, have lower compression ratios and are not as effective. It is therefore important to deal with more efficient lossy compression techniques. For them it is necessary to define quality criteria and level of acceptable distortion of image data. The usual multimedia approach is not possible to use for the scientific image data. They are optimized for human vision. This work deals with the influence of noise generated in the CCD structure to the defined quality criteria. It will also be shown the impact of the lossy standard JPEG2000 on quality of image data in astronomy.

  16. CCD noise influence on JPEG2000 compression of astronomical images

    NASA Astrophysics Data System (ADS)

    Páta, Petr

    2012-02-01

    Compression of astronomical images is still current task. In most applications, lossless approaches are used that do no damage to the compressed data. These algorithms, however, have lower compression ratios and are not as effective. It is therefore important to deal with more efficient lossy compression techniques. For them it is necessary to define quality criteria and level of acceptable distortion of image data. The usual multimedia approach is not possible to use for the scientific image data. They are optimized for human vision. This work deals with the influence of noise generated in the CCD structure to the defined quality criteria. It will also be shown the impact of the lossy standard JPEG2000 on quality of image data in astronomy.

  17. EEG compression of scalp recordings based on dipole fitting.

    PubMed

    Daou, Hoda; Labeau, Fabrice

    2015-05-01

    A novel technique for electroencephalogram (EEG) compression is proposed in this paper. This technique models the intrinsic dependence inherent between the different EEG channels. It is based on methods borrowed from dipole fitting that is usually used in order to find a solution to the classic problems in EEG analysis: inverse and forward problems. To compress the EEG signals, the forward model based on approximated source dipoles is first used to provide an approximation of the recorded signals. Then, (based on a smoothness factor) appropriate coding techniques are suggested to compress the residuals of the fitting process. Results show that this technique works well for different recordings and for different patients, and is even able to provide near-lossless compression for certain types of recordings. PMID:25122606

  18. Perceptual image compression for data transmission on the battlefield

    NASA Astrophysics Data System (ADS)

    Gonzalez, Jose G.; Smith, Mark J. T.; Hontsch, Ingo; Karam, Lina J.; Namuduri, Kameswara R.; Szu, Harold H.

    1998-07-01

    This paper treats the compression of Synthetic Aperture Radar (SAR) imagery. SAR images are difficult to compress, relative to natural images, because SAR contains an inherent high frequency speckle. Today's state-of-the-art coders are designed to work with natural images, which have a lower frequency content. Thus, their performance on SAR is under par. In this paper we given an overview performance report on the popular compressions techniques, and investigate three approaches to improve the quality of SAR compression at low- bit rates. First, we look at the design of optimal quantizers which we obtain by training on SAR data. Second, we explore the use of perceptual properties of the human visual system to improve subjective coding quality. Third, we consider the use of a model that separates the SAR image into structural and textural components. The paper concludes with a subjective evaluation of the algorithms based on the CCIR recommendation for the assessment of picture quality.

  19. Pseudoaneurysm of the Inferior Epigastric Artery Successfully Treated by Ultrasound-guided Compression

    SciTech Connect

    Takase, Kei Kazama, Takuro; Abe, Kayoko; Chiba, Yoshihiro; Saito, Haruo; Takahashi, Shoki

    2004-09-15

    An 82-year-old woman underwent right hemicolectomy by median laparotomy. Two weeks later, a pulsatile mass was found at the left side of the surgical wound, which was diagnosed as pseudoaneurysm of the inferior epigastric artery by color Doppler US and CT. The pseudoaneurysm was successfully treated by US-guided compression of the neck of the aneurysm for 30 minutes. US-guided compression should be considered the treatment of choice for postsurgical pseudoaneurysm of the inferior epigastric artery.

  20. Lossless image compression technique for infrared thermal images

    NASA Astrophysics Data System (ADS)

    Allred, Lloyd G.; Kelly, Gary E.

    1992-07-01

    The authors have achieved a 6.5-to-one image compression technique for thermal images (640 X 480, 1024 colors deep). Using a combination of new and more traditional techniques, the combined algorithm is computationally simple, enabling `on-the-fly' compression and storage of an image in less time than it takes to transcribe the original image to or from a magnetic medium. Similar compression has been achieved on visual images by virtue of the feature that all optical devices possess a modulation transfer function. As a consequence of this property, the difference in color between adjacent pixels is a usually small number, often between -1 and +1 graduations for a meaningful color scheme. By differentiating adjacent rows and columns, the original image can be expressed in terms of these small numbers. A simple compression algorithm for these small numbers achieves a four to one image compression. By piggy-backing this technique with a LZW compression or a fixed Huffman coding, an additional 35% image compression is obtained, resulting in a 6.5-to-one lossless image compression. Because traditional noise-removal operators tend to minimize the color graduations between adjacent pixels, an additional 20% reduction can be obtained by preprocessing the image with a noise-removal operator. Although noise removal operators are not lossless, their application may prove crucial in applications requiring high compression, such as the storage or transmission of a large number or images. The authors are working with the Air Force Photonics Technology Application Program Management office to apply this technique to transmission of optical images from satellites.

  1. Chiropractic management of a patient with ulnar nerve compression symptoms: a case report

    PubMed Central

    Illes, Jennifer D.; Johnson, Theodore L.

    2013-01-01

    Objective The purpose of this case report is to describe chiropractic management of a patient with arm and hand numbness and who was suspected to have ulnar nerve compression. Clinical Features A 41-year-old woman presented with hand weakness and numbness along the medial aspect of her right forearm and the 3 most medial fingers. The onset of symptoms presented suddenly, 3 weeks prior, when she woke up in the morning and assumed she had “slept wrong.” The patient’s posture showed protracted shoulders and moderate forward head carriage. Orthopedic assessment revealed symptomatic right elevated arm stress test, grip strength asymmetry, and a Tinel sign at the right cubital tunnel. Intervention and Outcome The patient was treated using chiropractic care, which consisted of manipulative therapy, myofascial therapy, and elastic therapeutic taping. Active home care included performing postural exercises and education about workstation ergonomics. She demonstrated immediate subjective improvement of her numbness and weakness after the first treatment. Over a series of 11 treatments, her symptoms resolved completely; and she was able to perform work tasks without dysfunction. Conclusion Chiropractic treatment consisting of manipulation, soft tissue mobilizations, exercise, and education of workstation ergonomics appeared to reduce the symptoms of ulnar nerve compression symptoms for this patient. PMID:24294148

  2. Compression fractures of the back

    MedlinePLUS

    Vertebral compression fractures ... the most common cause of this type of fracture. Osteoporosis is a disease in which bones become ... the spine, such as multiple myeloma Having many fractures of the vertebrae can lead to kyphosis . This ...

  3. Electrical conductivity of compressed argon

    SciTech Connect

    Bauer, R.; Windl, W.; Collins, L.; Kress, J.; Kwon, I.

    1997-10-01

    The authors report calculations of the electrical conductivity of solid argon as a function of compression within the density functional local density approximation formulation for a norm-conserving pseudopotential using both electron-phonon coupling and molecular dynamics techniques.

  4. Compressed gas fuel storage system

    DOEpatents

    Wozniak, John J. (Columbia, MD); Tiller, Dale B. (Lincoln, NE); Wienhold, Paul D. (Baltimore, MD); Hildebrand, Richard J. (Edgemere, MD)

    2001-01-01

    A compressed gas vehicle fuel storage system comprised of a plurality of compressed gas pressure cells supported by shock-absorbing foam positioned within a shape-conforming container. The container is dimensioned relative to the compressed gas pressure cells whereby a radial air gap surrounds each compressed gas pressure cell. The radial air gap allows pressure-induced expansion of the pressure cells without resulting in the application of pressure to adjacent pressure cells or physical pressure to the container. The pressure cells are interconnected by a gas control assembly including a thermally activated pressure relief device, a manual safety shut-off valve, and means for connecting the fuel storage system to a vehicle power source and a refueling adapter. The gas control assembly is enclosed by a protective cover attached to the container. The system is attached to the vehicle with straps to enable the chassis to deform as intended in a high-speed collision.

  5. Comparison of Artificial Compressibility Methods

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin; Housman, Jeffrey; Kwak, Dochan

    2004-01-01

    Various artificial compressibility methods for calculating the three-dimensional incompressible Navier-Stokes equations are compared. Each method is described and numerical solutions to test problems are conducted. A comparison based on convergence behavior, accuracy, and robustness is given.

  6. Compression ignition characteristics of coal slurry fuels

    SciTech Connect

    Brehob, D.D.

    1985-01-01

    Slow and medium speed compression ignition engines are devices with the potential for conversion to coal fueling. Recent work focuses on coal slurried in a liquid carrier. Engine studies on coal slurry to date have investigated the slurries' wear, thermal efficiency, and injection performance. Previously lacking information on the compression ignition characteristics of coal slurries, specifically, the ignition delay times and conditions for ignition of 45 mass% coal in methanol, oil, and water are compared to methanol and diesel No. 2. The slurries are evaluated using a 900 rpm, direct injection, square piston engine simulator operating for one combustion cycle per experiment. Both 16:1 and 22:1 compression ratios are used with inlet air temperatures from ambient to 250/sup 0/C and 2 atm abs supercharge. The square geometry accommodates windows on two opposite walls of the combustion chamber for complete optical access. High speed Schlieren, shadowgraphic, and direct cinematography show the qualitative features of the motoring and combusting cycles. The pressure and luminosity defined ignition delay times are 0.7 to 10 msec for the conditions of the experiment. All of the test fuels except coal/water slurry ignited at the operating conditions attainable in the engine simulator. The temperature at time of injection required to obtain ignition is approximately 680 K for diesel No. 2 and coal/diesel slurry, 725 K for coal/methanol slurry, and 825 K for neat methanol.

  7. Compressive failure of fibre composites

    NASA Astrophysics Data System (ADS)

    Budiansky, B.; Fleck, N. A.

    1993-01-01

    A REVIEW OF experimental data and elementary theoretical formulas for compressive failure of polymer matrix fibre composites indicates that the dominant failure mode is by plastic kinking. Initial local fibre misalignment plays a central role in the plastic kinking process. Theoretical analyses and numerical results for compressive kinking are presented, encompassing effects of strain-hardening, kink inclination, and applied shear stress. The assumption of rigid fibres is assessed critically, and the legitimacy of its use for polymer matrix composites is established.

  8. Steganography using wavelet compressed images

    NASA Astrophysics Data System (ADS)

    Spaulding, Jeremiah; Noda, Hideki; Shirazi, Mahdad N.; Niimi, Michiharu; Kawaguchi, Eiji

    2001-08-01

    Internet bandwidth is in high demand, and one way that web sites lower the amount of bandwidth they use is by compressing their site's images. This lowers the amount of bandwidth used, and makes the site load much faster. There are of course many other useful applications for compressed images. Bit Plane Complexity Segmentation (BPCS) digital picture steganography is a technique to hide data inside an image file. BPCS achieves high embedding rates with low distortion based on the theory that noise-like regions in a bit-plane can be replaced with noise-like secret data without discernible loss in image quality. This is possible because the human eye, while very good at distinguishing anomalies in areas of homogenous texture, is bad at distinguishing anomalies in visually complex areas. However, BPCS is not a robust embedding scheme, and any lossy compression usually destroys the data. Wavelet image compression using the Discreet Wavelet Transform (DWT) is the basis of many modern compression schemes. The coefficients generated by certain wavelet transforms have many image-like qualities. These qualities can be exploited to allow BPCS to be performed on the coefficients. The results can then be losslessly encoded, combining the good compression of the DWT with the high embedding rates of BPCS.

  9. How to perform chest compressions.

    PubMed

    Parry, Andrew

    2015-11-18

    Rationale and key points This article outlines the correct and effective technique for performing chest compressions for adults in cardiac arrest. Correct performance of chest compressions relies on various factors that are within the control of the nurse. Therefore, it is essential that nurses have comprehensive knowledge of this vital skill. Techniques that deviate from evidence-based recommendations may lead to an ineffective resuscitation attempt and unfavourable outcomes for patients. ? Accurate hand placement on the patient's chest is vital to ensure the heart is compressed effectively. ? Adhering to the recommended depth and rate of compression is fundamental to perfuse the myocardium. ? Interruptions to chest compressions should be kept to a minimum. Reflective activity Clinical skills articles can help update your practice and ensure it remains evidence based. Apply this article to your practice. Reflect on and write a short account of: 1. Your chest compression technique and consider if it follows the evidence base provided in this article. 2. How this article will change your practice. 3. The need to update your cardiopulmonary resuscitation skills. Subscribers can upload their reflective accounts at: rcni.com/portfolio . PMID:26576912

  10. Hyperelastic Material Properties of Mouse Skin under Compression

    PubMed Central

    Wang, Yuxiang; Marshall, Kara L.; Baba, Yoshichika; Gerling, Gregory J.; Lumpkin, Ellen A.

    2013-01-01

    The skin is a dynamic organ whose complex material properties are capable of withstanding continuous mechanical stress while accommodating insults and organism growth. Moreover, synchronized hair cycles, comprising waves of hair growth, regression and rest, are accompanied by dramatic fluctuations in skin thickness in mice. Whether such structural changes alter skin mechanics is unknown. Mouse models are extensively used to study skin biology and pathophysiology, including aging, UV-induced skin damage and somatosensory signaling. As the skin serves a pivotal role in the transfer function from sensory stimuli to neuronal signaling, we sought to define the mechanical properties of mouse skin over a range of normal physiological states. Skin thickness, stiffness and modulus were quantitatively surveyed in adult, female mice (Mus musculus). These measures were analyzed under uniaxial compression, which is relevant for touch reception and compression injuries, rather than tension, which is typically used to analyze skin mechanics. Compression tests were performed with 105 full-thickness, freshly isolated specimens from the hairy skin of the hind limb. Physiological variables included body weight, hair-cycle stage, maturity level, skin site and individual animal differences. Skin thickness and stiffness were dominated by hair-cycle stage at young (6–10 weeks) and intermediate (13–19 weeks) adult ages but by body weight in mature mice (26–34 weeks). Interestingly, stiffness varied inversely with thickness so that hyperelastic modulus was consistent across hair-cycle stages and body weights. By contrast, the mechanics of hairy skin differs markedly with anatomical location. In particular, skin containing fascial structures such as nerves and blood vessels showed significantly greater modulus than adjacent sites. Collectively, this systematic survey indicates that, although its structure changes dramatically throughout adult life, mouse skin at a given location maintains a constant elastic modulus to compression throughout normal physiological stages. PMID:23825661

  11. Using the Weekly Newspaper in Education.

    ERIC Educational Resources Information Center

    Becker, Sharon; Kendall, Stuart

    Intended for teachers in all subject areas at the elementary and secondary school levels, this booklet contains a variety of activities involving the use of the weekly newspaper as a teaching aid. Following a list of features of a weekly newspaper that make it suitable for classroom instruction, the activities are presented for elementary and…

  12. 76 FR 63801 - Fire Prevention Week, 2011

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-13

    ... the United States of America the two hundred and thirty-sixth. (Presidential Sig.) [FR Doc. 2011-26720... October 13, 2011 Part IV The President Proclamation 8732--Fire Prevention Week, 2011 Proclamation 8733...; #0;Title 3-- #0;The President ] Proclamation 8732 of October 7, 2011 Fire Prevention Week, 2011...

  13. 75 FR 62307 - Fire Prevention Week, 2010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-08

    ... Independence of the United States of America the two hundred and thirty-fifth. (Presidential Sig.) [FR Doc... Documents#0;#0; ] Proclamation 8577 of October 1, 2010 Fire Prevention Week, 2010 By the President of the United States of America A Proclamation During Fire Prevention Week, we reaffirm the importance of...

  14. National Poison Prevention Week Promotional Materials.

    ERIC Educational Resources Information Center

    Poison Prevention Week Council, Washington, DC.

    This collection of materials for parents, early childhood workers, the elderly, and anyone in situations requiring safeguards against poisoning, spans the years 1993 and 1994 and is intended to promote National Poison Prevention Week. The materials included are: (1) the 31-page, illustrated report on National Poison Prevention Week for 1993,…

  15. 75 FR 20891 - National Volunteer Week, 2010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-21

    ... United States of America the two hundred and thirty-fourth. (Presidential Sig.) [FR Doc. 2010-9415 Filed... Documents#0;#0; ] Proclamation 8500 of April 16, 2010 National Volunteer Week, 2010 By the President of the... country. This week, we recognize their enduring contributions and encourage more Americans, especially...

  16. 76 FR 72601 - National Family Week, 2011

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-23

    ... two hundred and thirty-sixth. (Presidential Sig.) [FR Doc. 2011-30454 Filed 11-22-11; 11:15 am... November 23, 2011 Part IV The President Proclamation 8756--National Family Week, 2011 Proclamation 8757--National Farm-City Week, 2011 Proclamation 8758--National Child's Day, 2011 Executive Order...

  17. 78 FR 69749 - American Education Week, 2013

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-20

    ... the two hundred and thirty- eighth. (Presidential Sig.) [FR Doc. 2013-28018 Filed 11-19-13; 11:15 am... November 20, 2013 Part II The President Proclamation 9058--American Education Week, 2013 #0; #0; #0... American Education Week, 2013 By the President of the United States of America A Proclamation Education...

  18. 78 FR 24323 - National Park Week, 2013

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-24

    ... the United States of America the two hundred and thirty- seventh. (Presidential Sig.) [FR Doc. 2013... Documents#0;#0; ] Proclamation 8961 of April 19, 2013 National Park Week, 2013 By the President of the... be passed on. During National Park Week, we celebrate the wonders entrusted to us by our...

  19. 78 FR 30729 - World Trade Week, 2013

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-22

    ... Independence of the United States of America the two hundred and thirty- seventh. (Presidential Sig.) [FR Doc... Documents#0;#0; ] Proclamation 8983 of May 17, 2013 World Trade Week, 2013 By the President of the United... Week, we recognize workers, growers, and entrepreneurs nationwide who share that ambition, and...

  20. 75 FR 71005 - American Education Week, 2010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-22

    ... thirty-fifth. (Presidential Sig.) [FR Doc. 2010-29516 Filed 11-19-10; 8:45 am] Billing code 3195-W1-P ... Education Week, 2010 By the President of the United States of America A Proclamation Education is essential to our success as both a people and a Nation. During American Education Week, we rededicate...

  1. 76 FR 29139 - World Trade Week, 2011

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-19

    ... Independence of the United States of America the two hundred and thirty-fifth. (Presidential Sig.) [FR Doc...#0;#0; ] Proclamation 8677 of May 13, 2011 World Trade Week, 2011 By the President of the United... interdependent. World Trade Week is a time to highlight the vital connection between the global economy and...

  2. 77 FR 22177 - National Volunteer Week, 2012

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-12

    .... (Presidential Sig.) [FR Doc. 2012-9017 Filed 4-11-12; 11:15 am] Billing code 3295-F2-P ... April 12, 2012 Part III The President Proclamation 8797--National Volunteer Week, 2012 Proclamation 8798--Pan American Day and Pan American Week, 2012 Proclamation 8799--National Former Prisoner of...

  3. 77 FR 31151 - World Trade Week, 2012

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-24

    ... hundred and thirty-sixth. (Presidential Sig.) [FR Doc. 2012-12880 Filed 5-23-12; 11:15 am] Billing code... Documents#0;#0; ] Proclamation 8827 of May 21, 2012 World Trade Week, 2012 By the President of the United... demand for goods and services designed and produced by Americans. During World Trade Week, we...

  4. 76 FR 43107 - Captive Nations Week, 2011

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-19

    ... hundred and thirty-sixth. (Presidential Sig.) [FR Doc. 2011-18367 Filed 7-18-11; 11:15 am] Billing code... July 19, 2011 Part IV The President Proclamation 8692--Captive Nations Week, 2011 #0; #0; #0... Nations Week, 2011 By the President of the United States of America A Proclamation There are times in...

  5. 75 FR 42279 - Captive Nations Week, 2010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-21

    ... and thirty-fifth. (Presidential Sig.) [FR Doc. 2010-17984 Filed 7-20-10; 8:45 am] Billing code 3195-W0... Documents#0;#0; #0; #0;Title 3-- #0;The President ] Proclamation 8541 of July 16, 2010 Captive Nations Week... and requested the President to issue a proclamation designating the third week of July of each year...

  6. 76 FR 20215 - National Volunteer Week, 2011

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-12

    ... hundred and thirty-fifth. (Presidential Sig.) [FR Doc. 2011-8837 Filed 4-11-11; 8:45 am] Billing code 3195... Week, 2011 By the President of the United States of America A Proclamation America's story has been... they see a need. During National Volunteer Week, we celebrate the profound impact of volunteers...

  7. 76 FR 22001 - National Park Week, 2011

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-20

    ... the two hundred and thirty-fifth. (Presidential Sig.) [FR Doc. 2011-9730 Filed 4-19-11; 8:45 am... Documents#0;#0; ] Proclamation 8656 of April 15, 2011 National Park Week, 2011 By the President of the.... ``Healthy Parks, Healthy People,'' the focus for this year's National Park Week, highlights the role...

  8. 75 FR 28183 - World Trade Week, 2010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-20

    ... the United States of America the two hundred and thirty-fourth. (Presidential Sig.) [FR Doc. 2010...#0;#0; ] Proclamation 8521 of May 12, 2010 World Trade Week, 2010 By the President of the United.... World Trade Week is an opportunity for us to reaffirm the importance of trade to our Nation's...

  9. 75 FR 29393 - Small Business Week, 2010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-26

    ... thirty-fourth. (Presidential Sig.) [FR Doc. 2010-12755 Filed 5-25-10; 8:45 am] Billing code 3195-W0-P ... Documents#0;#0; ] Proclamation 8525 of May 20, 2010 Small Business Week, 2010 By the President of the United... new private sector jobs. During Small Business Week, we reaffirm our support for America's...

  10. 77 FR 68045 - American Education Week, 2012

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-15

    .... (Presidential Sig.) [FR Doc. 2012-27922 Filed 11-14-12; 8:45 am] Billing code 3295-F3 ... Documents#0;#0; ] Proclamation 8904 of November 9, 2012 American Education Week, 2012 By the President of... Nation's economic prosperity and civic life. This week, we reaffirm our national mission of educating...

  11. 75 FR 70999 - National Entrepreneurship Week, 2010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-19

    ... Independence of the United States of America the two hundred and thirty-fifth. (Presidential Sig.) [FR Doc... Proclamation 8600--National Entrepreneurship Week, 2010 Proclamation 8601--America Recycles Day, 2010 #0; #0... 15, 2010 National Entrepreneurship Week, 2010 By the President of the United States of America...

  12. 78 FR 24321 - National Volunteer Week, 2013

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-24

    ... of America the two hundred and thirty- seventh. (Presidential Sig.) [FR Doc. 2013-09867 Filed 4-23-13... Documents#0;#0; ] Proclamation 8960 of April 19, 2013 National Volunteer Week, 2013 By the President of the... accept certain obligations to one another. National Volunteer Week is a time to renew that...

  13. 77 FR 24575 - National Park Week, 2012

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-25

    ... Independence of the United States of America the two hundred and thirty-sixth. (Presidential Sig.) [FR Doc... Documents#0;#0; #0; #0;Title 3-- #0;The President ] Proclamation 8801 of April 20, 2012 National Park Week... National Park Week, all 397 National Parks will offer free admission from April 21 through April 29,...

  14. 77 FR 69733 - National Family Week, 2012

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-21

    ... States of America the two hundred and thirty-seventh. (Presidential Sig.) [FR Doc. 2012-28457 Filed 11-20... Week, 2012 By the President of the United States of America A Proclamation The bonds that tie us to our... strength of character in their children. This week, we celebrate the unity and compassion that keep...

  15. 78 FR 71431 - National Family Week, 2013

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-27

    ....) [FR Doc. 2013-28734 Filed 11-26-13; 11:15 am] Billing code 3295-F4 ... November 27, 2013 Part V The President Proclamation 9061--National Family Week, 2013 #0; #0; #0... National Family Week, 2013 By the President of the United States of America A Proclamation Whether...

  16. 78 FR 44867 - Captive Nations Week, 2013

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

    ... Independence of the United States of America the two hundred and thirty- eighth. (Presidential Sig.) [FR Doc... July 24, 2013 Part VI The President Proclamation 8998--Captive Nations Week, 2013 #0; #0; #0... Nations Week, 2013 By the President of the United States of America A Proclamation As citizens of...

  17. Using the Weekly Newspaper in Education.

    ERIC Educational Resources Information Center

    Becker, Sharon; Kendall, Stuart

    Intended for teachers in all subject areas at the elementary and secondary school levels, this booklet contains a variety of activities involving the use of the weekly newspaper as a teaching aid. Following a list of features of a weekly newspaper that make it suitable for classroom instruction, the activities are presented for elementary and…

  18. Symmetric Toeplitz-Structured Compressed Sensing Matrices

    NASA Astrophysics Data System (ADS)

    Huang, Tao; Fan, Yi-Zheng; Zhu, Ming

    2015-11-01

    How to construct a suitable measurement matrix is an important topic in compressed sensing. A significant part of the recent work is that the measurement matrices are not completely random on the entries but exhibit some considerable structures. In this paper, we proved that a symmetric Toeplitz matrix and its variant can be used as measurement matrices and recovery signal with high probability. Compared with random matrices (e.g. Gaussian and Bernoulli matrices) and some structured matrices (e.g. Toeplitz and circulant matrices), we need to generate fewer independent entries to obtain the measurement matrix while the effectiveness of the recovery keeps good.

  19. Compressed sensing for phase contrast CT

    SciTech Connect

    Gaass, Thomas; Potdevin, Guillaume; Noeel, Peter B.; Tapfer, Arne; Willner, Marian; Herzen, Julia; Bech, Martin; Pfeiffer, Franz; Haase, Axel

    2012-07-31

    Modern x-ray techniques opened the possibility to retrieve phase information. Phase-contrast computed tomography (PCCT) has the potential to significantly improve soft tissue contrast. Radiation dose, however, continues to be an issue when moving from bench to bedside. Dose reduction in this work is achieved by sparsely acquiring PCCT data. To compensate for appearing aliasing artifacts we introduce a compressed sensing (CS) reconstruction framework. We present the feasibility of CS on PCCT with numerical as well as measured phantom data. The results proof that CS compensates for under-sampling artifacts and maintains the superior soft tissue contrast and detail visibility in the reconstructed images.

  20. Compression strength of composite primary structural components

    NASA Technical Reports Server (NTRS)

    Johnson, Eric R.

    1992-01-01

    A status report of work performed during the period May 1, 1992 to October 31, 1992 is presented. Research was conducted in three areas: delamination initiation in postbuckled dropped-ply laminates; stiffener crippling initiated by delamination; and pressure pillowing of an orthogonally stiffened cylindrical shell. The geometrically nonlinear response and delamination initiation of compression-loaded dropped-ply laminates is analyzed. A computational model of the stiffener specimens that includes the capability to predict the interlaminar response at the flange free edge in postbuckling is developed. The distribution of the interacting loads between the stiffeners and the shell wall, particularly at the load transfer at the stiffener crossing point, is determined.

  1. Estimating JPEG2000 compression for image forensics using Benford's Law

    NASA Astrophysics Data System (ADS)

    Qadir, Ghulam; Zhao, Xi; Ho, Anthony T. S.

    2010-05-01

    With the tremendous growth and usage of digital images nowadays, the integrity and authenticity of digital content is becoming increasingly important, and a growing concern to many government and commercial sectors. Image Forensics, based on a passive statistical analysis of the image data only, is an alternative approach to the active embedding of data associated with Digital Watermarking. Benford's Law was first introduced to analyse the probability distribution of the 1st digit (1-9) numbers of natural data, and has since been applied to Accounting Forensics for detecting fraudulent income tax returns [9]. More recently, Benford's Law has been further applied to image processing and image forensics. For example, Fu et al. [5] proposed a Generalised Benford's Law technique for estimating the Quality Factor (QF) of JPEG compressed images. In our previous work, we proposed a framework incorporating the Generalised Benford's Law to accurately detect unknown JPEG compression rates of watermarked images in semi-fragile watermarking schemes. JPEG2000 (a relatively new image compression standard) offers higher compression rates and better image quality as compared to JPEG compression. In this paper, we propose the novel use of Benford's Law for estimating JPEG2000 compression for image forensics applications. By analysing the DWT coefficients and JPEG2000 compression on 1338 test images, the initial results indicate that the 1st digit probability of DWT coefficients follow the Benford's Law. The unknown JPEG2000 compression rates of the image can also be derived, and proved with the help of a divergence factor, which shows the deviation between the probabilities and Benford's Law. Based on 1338 test images, the mean divergence for DWT coefficients is approximately 0.0016, which is lower than DCT coefficients at 0.0034. However, the mean divergence for JPEG2000 images compression rate at 0.1 is 0.0108, which is much higher than uncompressed DWT coefficients. This result clearly indicates a presence of compression in the image. Moreover, we compare the results of 1st digit probability and divergence among JPEG2000 compression rates at 0.1, 0.3, 0.5 and 0.9. The initial results show that the expected difference among them could be used for further analysis to estimate the unknown JPEG2000 compression rates.

  2. Expanding Window Compressed Sensing for Non-Uniform Compressible Signals

    PubMed Central

    Liu, Yu; Zhu, Xuqi; Zhang, Lin; Cho, Sung Ho

    2012-01-01

    Many practical compressible signals like image signals or the networked data in wireless sensor networks have non-uniform support distribution in their sparse representation domain. Utilizing this prior information, a novel compressed sensing (CS) scheme with unequal protection capability is proposed in this paper by introducing a windowing strategy called expanding window compressed sensing (EW-CS). According to the importance of different parts of the signal, the signal is divided into several nested subsets, i.e., the expanding windows. Each window generates its own measurements using a random sensing matrix. The more significant elements are contained by more windows, so they are captured by more measurements. This design makes the EW-CS scheme have more convenient implementation and better overall recovery quality for non-uniform compressible signals than ordinary CS schemes. These advantages are theoretically analyzed and experimentally confirmed. Moreover, the EW-CS scheme is applied to the compressed acquisition of image signals and networked data where it also has superior performance than ordinary CS and the existing unequal protection CS schemes. PMID:23201984

  3. Alternative Work Schedules in Office and Nonoffice Work Settings.

    ERIC Educational Resources Information Center

    Kirk, Raymond J.; Barton, H. David

    A rapidly growing change in the workplace is the replacement of a fixed work schedule with a variety of alternative work schedules (AWS), including both flexible and compressed schedules. Experimenting organizations (N=901) evaluated one of four major categories of AWS in office and nonoffice settings, i.e., a flexible 8-hour day;…

  4. 29 CFR 1917.154 - Compressed air.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Compressed air. 1917.154 Section 1917.154 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.154 Compressed air. Employees shall be... this part during cleaning with compressed air. Compressed air used for cleaning shall not exceed...

  5. 29 CFR 1917.154 - Compressed air.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Compressed air. 1917.154 Section 1917.154 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.154 Compressed air. Employees shall be... this part during cleaning with compressed air. Compressed air used for cleaning shall not exceed...

  6. 29 CFR 1917.154 - Compressed air.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Compressed air. 1917.154 Section 1917.154 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.154 Compressed air. Employees shall be... this part during cleaning with compressed air. Compressed air used for cleaning shall not exceed...

  7. 29 CFR 1917.154 - Compressed air.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Compressed air. 1917.154 Section 1917.154 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.154 Compressed air. Employees shall be... this part during cleaning with compressed air. Compressed air used for cleaning shall not exceed...

  8. 29 CFR 1917.154 - Compressed air.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Compressed air. 1917.154 Section 1917.154 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.154 Compressed air. Employees shall be... this part during cleaning with compressed air. Compressed air used for cleaning shall not exceed...

  9. Perceptual Image Compression in Telemedicine

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Ahumada, Albert J., Jr.; Eckstein, Miguel; Null, Cynthia H. (Technical Monitor)

    1996-01-01

    The next era of space exploration, especially the "Mission to Planet Earth" will generate immense quantities of image data. For example, the Earth Observing System (EOS) is expected to generate in excess of one terabyte/day. NASA confronts a major technical challenge in managing this great flow of imagery: in collection, pre-processing, transmission to earth, archiving, and distribution to scientists at remote locations. Expected requirements in most of these areas clearly exceed current technology. Part of the solution to this problem lies in efficient image compression techniques. For much of this imagery, the ultimate consumer is the human eye. In this case image compression should be designed to match the visual capacities of the human observer. We have developed three techniques for optimizing image compression for the human viewer. The first consists of a formula, developed jointly with IBM and based on psychophysical measurements, that computes a DCT quantization matrix for any specified combination of viewing distance, display resolution, and display brightness. This DCT quantization matrix is used in most recent standards for digital image compression (JPEG, MPEG, CCITT H.261). The second technique optimizes the DCT quantization matrix for each individual image, based on the contents of the image. This is accomplished by means of a model of visual sensitivity to compression artifacts. The third technique extends the first two techniques to the realm of wavelet compression. Together these two techniques will allow systematic perceptual optimization of image compression in NASA imaging systems. Many of the image management challenges faced by NASA are mirrored in the field of telemedicine. Here too there are severe demands for transmission and archiving of large image databases, and the imagery is ultimately used primarily by human observers, such as radiologists. In this presentation I will describe some of our preliminary explorations of the applications of our technology to the special problems of telemedicine.

  10. Evolution of some Los Alamos flux compression programs

    SciTech Connect

    Fowler, C.M.; Goforth, J.H.

    1996-12-31

    When we were approached to give a general discussion of some aspects of the Los Alamos flux compression program, we decided to present historical backgrounds of a few topics that have some relevance to programs that we very much In the forefront of activities going on today. Of some thirty abstracts collected at Los Alamos for this conference, ten of them dealt with electromagnetic acceleration of materials, notably the compression of heavy liners, and five dealt with plasma compression. Both of these topics have been under investigation, off and on, from the time a formal flux compression program was organized at Los Alamos. We decided that a short overview of work done In these areas would be of some interest. Some of the work described below has been discussed in Laboratory reports that, while referenced and available, are not readily accessible. For completeness, some previously published, accessible work Is also discussed but much more briefly. Perhaps the most striking thing about the early work In these two areas is how primitive much of it was when compared to the far more sophisticated, related activities of today. Another feature of these programs, actually for most programs, Is their cyclic nature. Their relevance and/or funding seems to come land go. Eventually, many of the older programs come back into favor. Activities Involving the dense plasma focus (DPF), about which some discussions will be given later, furnish a classic example of this kind, coming Into and then out of periods of heightened interest. We devote the next two sections of this paper to a review of our work In magnetic acceleration of solids and of plasma compression. A final section gives a survey of our work In which thin foils are imploded to produce intense quantities of son x-rays. The authors are well aware of much excellent work done elsewhere In all of these topics, but partly because of space limitations, have confined this discussion to work done at Los Alamos.

  11. Ambient Compression-Compression Fatigue Behavior of Magnesium Single Crystal

    NASA Astrophysics Data System (ADS)

    Li, Qizhen

    2014-01-01

    A magnesium single crystal sample with a near orientation was tested at room temperature under compression-compression cyclic loading, and the microstructure was characterized to disclose the involved deformation mechanisms. No plastic deformation region appeared on the stress-strain curve during the cyclic loading. The stress-strain curve stabilized at the first cycle, the strain range for each cycle fluctuated slightly around a constant value, and the mean strain for each cycle was in a narrow range from 0.0846 to 0.0863 during the whole test. The ratcheting strain rate decreased exponentially from ~0.0003, and reached a relatively small and stable value of about zero. The observed deformation mechanisms were prismatic slip, compression twinning, and tension twinning. The prismatic dislocation slip roughened the cylindrical sample surface by forming extrusions and intrusions, and small cracks were also observed on the surface.

  12. Inflammatory cascades mediate synapse elimination in spinal cord compression

    PubMed Central

    2014-01-01

    Background Cervical compressive myelopathy (CCM) is caused by chronic spinal cord compression due to spondylosis, a degenerative disc disease, and ossification of the ligaments. Tip-toe walking Yoshimura (twy) mice are reported to be an ideal animal model for CCM-related neuronal dysfunction, because they develop spontaneous spinal cord compression without any artificial manipulation. Previous histological studies showed that neurons are lost due to apoptosis in CCM, but the mechanism underlying this neurodegeneration was not fully elucidated. The purpose of this study was to investigate the pathophysiology of CCM by evaluating the global gene expression of the compressed spinal cord and comparing the transcriptome analysis with the physical and histological findings in twy mice. Methods Twenty-week-old twy mice were divided into two groups according to the magnetic resonance imaging (MRI) findings: a severe compression (S) group and a mild compression (M) group. The transcriptome was analyzed by microarray and RT-PCR. The cellular pathophysiology was examined by immunohistological analysis and immuno-electron microscopy. Motor function was assessed by Rotarod treadmill latency and stride-length tests. Results Severe cervical calcification caused spinal canal stenosis and low functional capacity in twy mice. The microarray analysis revealed 215 genes that showed significantly different expression levels between the S and the M groups. Pathway analysis revealed that genes expressed at higher levels in the S group were enriched for terms related to the regulation of inflammation in the compressed spinal cord. M1 macrophage-dominant inflammation was present in the S group, and cysteine-rich protein 61 (Cyr61), an inducer of M1 macrophages, was markedly upregulated in these spinal cords. Furthermore, C1q, which initiates the classical complement cascade, was more upregulated in the S group than in the M group. The confocal and electron microscopy observations indicated that classically activated microglia/macrophages had migrated to the compressed spinal cord and eliminated synaptic terminals. Conclusions We revealed the detailed pathophysiology of the inflammatory response in an animal model of chronic spinal cord compression. Our findings suggest that complement-mediated synapse elimination is a central mechanism underlying the neurodegeneration in CCM. PMID:24589419

  13. SCADA Protocol Anomaly Detection Utilizing Compression (SPADUC) 2013

    SciTech Connect

    Gordon Rueff; Lyle Roybal; Denis Vollmer

    2013-01-01

    There is a significant need to protect the nation’s energy infrastructures from malicious actors using cyber methods. Supervisory, Control, and Data Acquisition (SCADA) systems may be vulnerable due to the insufficient security implemented during the design and deployment of these control systems. This is particularly true in older legacy SCADA systems that are still commonly in use. The purpose of INL’s research on the SCADA Protocol Anomaly Detection Utilizing Compression (SPADUC) project was to determine if and how data compression techniques could be used to identify and protect SCADA systems from cyber attacks. Initially, the concept was centered on how to train a compression algorithm to recognize normal control system traffic versus hostile network traffic. Because large portions of the TCP/IP message traffic (called packets) are repetitive, the concept of using compression techniques to differentiate “non-normal” traffic was proposed. In this manner, malicious SCADA traffic could be identified at the packet level prior to completing its payload. Previous research has shown that SCADA network traffic has traits desirable for compression analysis. This work investigated three different approaches to identify malicious SCADA network traffic using compression techniques. The preliminary analyses and results presented herein are clearly able to differentiate normal from malicious network traffic at the packet level at a very high confidence level for the conditions tested. Additionally, the master dictionary approach used in this research appears to initially provide a meaningful way to categorize and compare packets within a communication channel.

  14. A new compression format for fiber tracking datasets.

    PubMed

    Presseau, Caroline; Jodoin, Pierre-Marc; Houde, Jean-Christophe; Descoteaux, Maxime

    2015-04-01

    A single diffusion MRI streamline fiber tracking dataset may contain hundreds of thousands, and often millions of streamlines and can take up to several gigabytes of memory. This amount of data is not only heavy to compute, but also difficult to visualize and hard to store on disk (especially when dealing with a collection of brains). These problems call for a fiber-specific compression format that simplifies its manipulation. As of today, no fiber compression format has yet been adopted and the need for it is now becoming an issue for future connectomics research. In this work, we propose a new compression format, .zfib, for streamline tractography datasets reconstructed from diffusion magnetic resonance imaging (dMRI). Tracts contain a large amount of redundant information and are relatively smooth. Hence, they are highly compressible. The proposed method is a processing pipeline containing a linearization, a quantization and an encoding step. Our pipeline is tested and validated under a wide range of DTI and HARDI tractography configurations (step size, streamline number, deterministic and probabilistic tracking) and compression options. Similar to JPEG, the user has one parameter to select: a worst-case maximum tolerance error in millimeter (mm). Overall, we find a compression factor of more than 96% for a maximum error of 0.1mm without any perceptual change or change of diffusion statistics (mean fractional anisotropy and mean diffusivity) along bundles. This opens new opportunities for connectomics and tractometry applications. PMID:25592997

  15. An Evaluation of a Two Week Teaching Trial Using Interactive Video Technology: Perceptions of Students and Staff.

    ERIC Educational Resources Information Center

    Baker, R. A.; Hansford, B. C.

    This report is concerned with an evaluation of a 2-week teaching trial in 1989 that utilized compressed data--interactive video technology. The trial was a collaborative venture of the University of New England (UNE), TELECOM, the Department of Education, Employment and Training (DEET), and SONY. In general, the University of New England supplied…

  16. Competitive Parallel Processing For Compression Of Data

    NASA Technical Reports Server (NTRS)

    Diner, Daniel B.; Fender, Antony R. H.

    1990-01-01

    Momentarily-best compression algorithm selected. Proposed competitive-parallel-processing system compresses data for transmission in channel of limited band-width. Likely application for compression lies in high-resolution, stereoscopic color-television broadcasting. Data from information-rich source like color-television camera compressed by several processors, each operating with different algorithm. Referee processor selects momentarily-best compressed output.

  17. Compression of spectral meteorological imagery

    NASA Technical Reports Server (NTRS)

    Miettinen, Kristo

    1993-01-01

    Data compression is essential to current low-earth-orbit spectral sensors with global coverage, e.g., meteorological sensors. Such sensors routinely produce in excess of 30 Gb of data per orbit (over 4 Mb/s for about 110 min) while typically limited to less than 10 Gb of downlink capacity per orbit (15 minutes at 10 Mb/s). Astro-Space Division develops spaceborne compression systems for compression ratios from as little as three to as much as twenty-to-one for high-fidelity reconstructions. Current hardware production and development at Astro-Space Division focuses on discrete cosine transform (DCT) systems implemented with the GE PFFT chip, a 32x32 2D-DCT engine. Spectral relations in the data are exploited through block mean extraction followed by orthonormal transformation. The transformation produces blocks with spatial correlation that are suitable for further compression with any block-oriented spatial compression system, e.g., Astro-Space Division's Laplacian modeler and analytic encoder of DCT coefficients.

  18. Flux Compression in HTS Films

    NASA Astrophysics Data System (ADS)

    Mikheenko, P.; Colclough, M. S.; Chakalov, R.; Kawano, K.; Muirhead, C. M.

    We report on experimental investigation of the effect of flux compression in superconducting YBa2Cu3Ox (YBCO) films and YBCO/CMR (Colossal Magnetoresistive) multilayers. The flux compression produces positive magnetic moment (m) upon the cooling in a field from above to below the critical temperature. We found effect of compression in all measured films and multilayers. In accordance with theoretical calculations, m is proportional to applied magnetic field. The amplitude of the effect depends on the cooling rate, which suggests the inhomogeneous cooling as its origin. The positive moment is always very small, a fraction of a percent of the ideal diamagnetic response. A CMR layer in contact with HTS decreases the amplitude of the effect. The flux compression weakly depends on sample size, but sensitive to its form and topology. The positive magnetic moment does not appear in bulk samples at low rates of the cooling. Our results show that the main features of the flux compression are very different from those in Paramagnetic Meissner effect observed in bulk high temperature superconductors and Nb disks.

  19. Performance Enhancement Technology for the Vapor Compression Refrigeration Cycle

    NASA Astrophysics Data System (ADS)

    Man'o, Tatsunori

    High efficiency refrigerator have been developed. For energy saving that is concerned with against global warming, performance enhancement of vapor compression refrigerator is required in field of air condition and refrigeration facility. In this paper, a review of recent performance enhancement technologies for the vapor compression refrigeration cycle is presented. This review contains high performance cycles of large sized centrifugal chiller, small to middle sized chiller and packaged air conditioner. Moreover, researches and developments of the refrigeration cycle recovering throttling loss, applications of ejector to boost in compressor suction pressure and to recirculate vapor refrigerant in the evaporator for heat transfer enhancement, and applications of expander to employ expansion work for compression work, are reviewed.

  20. 30 CFR 75.1730 - Compressed air; general; compressed air systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compressed air; general; compressed air systems... Compressed air; general; compressed air systems. (a) All pressure vessels shall be constructed, installed... Safety and Health district office. (b) Compressors and compressed-air receivers shall be equipped...

  1. 30 CFR 75.1730 - Compressed air; general; compressed air systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Compressed air; general; compressed air systems... Compressed air; general; compressed air systems. (a) All pressure vessels shall be constructed, installed... Safety and Health district office. (b) Compressors and compressed-air receivers shall be equipped...

  2. 30 CFR 75.1730 - Compressed air; general; compressed air systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Compressed air; general; compressed air systems... Compressed air; general; compressed air systems. (a) All pressure vessels shall be constructed, installed... Safety and Health district office. (b) Compressors and compressed-air receivers shall be equipped...

  3. 30 CFR 75.1730 - Compressed air; general; compressed air systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Compressed air; general; compressed air systems... Compressed air; general; compressed air systems. (a) All pressure vessels shall be constructed, installed... Safety and Health district office. (b) Compressors and compressed-air receivers shall be equipped...

  4. 30 CFR 75.1730 - Compressed air; general; compressed air systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compressed air; general; compressed air systems... Compressed air; general; compressed air systems. (a) All pressure vessels shall be constructed, installed... Safety and Health district office. (b) Compressors and compressed-air receivers shall be equipped...

  5. Imaging industry expectations for compressed sensing in MRI

    NASA Astrophysics Data System (ADS)

    King, Kevin F.; Kanwischer, Adriana; Peters, Rob

    2015-09-01

    Compressed sensing requires compressible data, incoherent acquisition and a nonlinear reconstruction algorithm to force creation of a compressible image consistent with the acquired data. MRI images are compressible using various transforms (commonly total variation or wavelets). Incoherent acquisition of MRI data by appropriate selection of pseudo-random or non-Cartesian locations in k-space is straightforward. Increasingly, commercial scanners are sold with enough computing power to enable iterative reconstruction in reasonable times. Therefore integration of compressed sensing into commercial MRI products and clinical practice is beginning. MRI frequently requires the tradeoff of spatial resolution, temporal resolution and volume of spatial coverage to obtain reasonable scan times. Compressed sensing improves scan efficiency and reduces the need for this tradeoff. Benefits to the user will include shorter scans, greater patient comfort, better image quality, more contrast types per patient slot, the enabling of previously impractical applications, and higher throughput. Challenges to vendors include deciding which applications to prioritize, guaranteeing diagnostic image quality, maintaining acceptable usability and workflow, and acquisition and reconstruction algorithm details. Application choice depends on which customer needs the vendor wants to address. The changing healthcare environment is putting cost and productivity pressure on healthcare providers. The improved scan efficiency of compressed sensing can help alleviate some of this pressure. Image quality is strongly influenced by image compressibility and acceleration factor, which must be appropriately limited. Usability and workflow concerns include reconstruction time and user interface friendliness and response. Reconstruction times are limited to about one minute for acceptable workflow. The user interface should be designed to optimize workflow and minimize additional customer training. Algorithm concerns include the decision of which algorithms to implement as well as the problem of optimal setting of adjustable parameters. It will take imaging vendors several years to work through these challenges and provide solutions for a wide range of applications.

  6. Radiator debris removing apparatus and work machine using same

    DOEpatents

    Martin, Kevin L.; Elliott, Dwight E.

    2008-09-02

    A radiator assembly includes a finned radiator core and a debris removing apparatus having a compressed air inlet and at least one compressed air outlet configured to direct compressed air through the radiator core. A work machine such as a wheel loader includes a radiator and a debris removing apparatus coupled with on-board compressed air and having at least one pressurized gas outlet configured to direct a gas toward the face of the radiator.

  7. Gradient Compression Stockings may Prevent Recovery after Bed Rest Deconditioning

    NASA Technical Reports Server (NTRS)

    Stenger, Michael B.; Lee, Stuart M.; Westby, Christian M.; Willig, Michael C.; Platts, Steven H.

    2011-01-01

    Introduction: Astronauts continue to wear a compression garment during and immediately after landing to prevent orthostatic intolerance (OI). We recently developed a custom-fitted, 3-piece garment that consists of thigh-high stockings with biker-style shorts that provides continuous, gradient compression: 55 mmHg at the ankle that decreases to approximately 20 mmHg at the top of the leg and 15 mmHg over the abdomen. This garment has been shown to be effective in preventing symptoms of OI during a short stand test after Space Shuttle missions, but symptoms may persist for several days after a long-duration mission in some astronauts. The purpose of this study was to confirm the effectiveness of wearing these elastic, gradient compression garments during orthostatic testing after 2 weeks of 6 degree head-down tilt bed rest as a model of spaceflight and to determine whether they would impact recovery after bed rest. Methods: Eight (5 treatment, 3 control) of 16 subjects have completed this study to-date. All subjects wore the 3-piece garment from waking until tilt testing (3 h) as a simulation of the timeline for astronauts on landing day (BR+0). Control subjects removed the garment after the tilt test. Treatment subjects wore the garment for the remainder of the day and wore lower compression thigh-high only garments on the day after bed rest (BR+1). Blood pressure, heart rate, and stroke volume responses to a 15-min 80 degree head-up tilt test were determined before 2 weeks of 6 degree head-down tilt, and on BR+0 and BR+1. Plasma volume (PV) was measured before each of these test sessions. Data are mean SE. Results: Compression garments prevented signs of OI on BR+0; all subjects in both groups completed the full 15-min test. Heart rate responses to tilt were lower on BR+0 than all other test days. Control subjects demonstrated a marginal PV decrease after bed rest, but showed typical recovery the day after bed rest (BR+0: 2.32 plus or minus 0.15 L to BR+1: 2.79 plus or minus 0.15 L). Treatment subjects did not recover PV the day after bed rest (BR+0: 2.61 plus or minus 0.23 L to BR+1: 2.61 plus or minus 0.23 L). Conclusion: Abdomen-high compression garments, which are effective in preventing post-bed rest orthostatic intolerance, may slow recovery of PV. Modified garments with reduced compression may be necessary to prevent prolonging recovery.

  8. Hybrid Vapor Compression Adsorption System: Thermal Storage Using Hybrid Vapor Compression Adsorption System

    SciTech Connect

    2012-01-04

    HEATS Project: UTRC is developing a new climate-control system for EVs that uses a hybrid vapor compression adsorption system with thermal energy storage. The targeted, closed system will use energy during the battery-charging step to recharge the thermal storage, and it will use minimal power to provide cooling or heating to the cabin during a drive cycle. The team will use a unique approach of absorbing a refrigerant on a metal salt, which will create a lightweight, high-energy-density refrigerant. This unique working pair can operate indefinitely as a traditional vapor compression heat pump using electrical energy, if desired. The project will deliver a hot-and-cold battery that provides comfort to the passengers using minimal power, substantially extending the driving range of EVs.

  9. Compression of fingerprint data using the wavelet vector quantization image compression algorithm. 1992 progress report

    SciTech Connect

    Bradley, J.N.; Brislawn, C.M.

    1992-04-11

    This report describes the development of a Wavelet Vector Quantization (WVQ) image compression algorithm for fingerprint raster files. The pertinent work was performed at Los Alamos National Laboratory for the Federal Bureau of Investigation. This document describes a previously-sent package of C-language source code, referred to as LAFPC, that performs the WVQ fingerprint compression and decompression tasks. The particulars of the WVQ algorithm and the associated design procedure are detailed elsewhere; the purpose of this document is to report the results of the design algorithm for the fingerprint application and to delineate the implementation issues that are incorporated in LAFPC. Special attention is paid to the computation of the wavelet transform, the fast search algorithm used for the VQ encoding, and the entropy coding procedure used in the transmission of the source symbols.

  10. Compressive behavior of fine sand.

    SciTech Connect

    Martin, Bradley E.; Kabir, Md. E.; Song, Bo; Chen, Wayne

    2010-04-01

    The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trends were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.

  11. Video compression by coefficient compensation

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Hirohisa

    1994-05-01

    This paper discusses a new video compression algorithm called Coefficient Compensation that achieves high performance by optimizing the DCT encoding loop structure, and demonstrates its improvement characteristic as compared with the conventional JPEG or MPEG I/P picture encoding under the condition that movement compensation is not available. The first part of the paper analyzes the performance of the DCT encoding loop structure, the method of optimization and the concept of soft-decision. The second part reports on the simulation results. Encoding performance is tested by various MPEG test sequences compressed in 20 Mbits/sec. The difference between JPEG and MPEG I is in the quantization table. For JPEG, the quantization table widely accepted as one producing a good compression quality is used. All the encoded binary outputs are fully compatible to the MPEG2 syntax but additional 2 bits/block information is coded as the user data for the Coefficient Compensation.

  12. Efficient access of compressed data

    SciTech Connect

    Eggers, S.J.; Shoshani, A.

    1980-06-01

    A compression technique is presented that allows a high degree of compression but requires only logarithmic access time. The technique is a constant suppression scheme, and is most applicable to stable databases whose distribution of constants is fairly clustered. Furthermore, the repeated use of the technique permits the suppression of a multiple number of different constants. Of particular interest is the application of the constant suppression technique to databases the composite key of which is made up of an incomplete cross product of several attribute domains. The scheme for compressing the full cross product composite key is well known. This paper, however, also handles the general, incomplete case by applying the constant suppression technique in conjunction with a composite key suppression scheme.

  13. About-weekly variations in nocturia.

    PubMed

    Cornélissen, Germaine; Axelrod, David E; Halberg, Franz

    2004-10-01

    The aim of this study was to assess components of variation in nocturia and to determine any putative geomagnetic influence. A 54-year old man with benign prostatic hyperplasia had recorded for about 4 years the number of times he awoke each night to urinate. The data have been reanalyzed for chronomics, the mapping of time structures (chronomes), involving the computation of least squares spectra of the urinary record and of environmental variables recorded during the same 4-year span. In addition to the previously reported monthly variation, other periodicities have been documented, including two separate components with periods of one week and of a near-week. The precise 7-day period may be a mainly exogenous resonance with external influences such as a weekly social schedule, whereas the near-week may be a partial resonance with natural changes in geomagnetics, reflecting in part changes in other non-photic natural environmental factors. PMID:15754853

  14. Compressing images of sparse histograms

    NASA Astrophysics Data System (ADS)

    Starosolski, Roman

    2005-09-01

    Most single-frame single-band medical images, like CR, CT, and MR, are of a high nominal bit depth, which usually varies from 12 to 16 bits per pixel. The actual number of pixels' intensity levels found in those images may be smaller, than implied by the nominal bit depth, by an order of magnitude or even more. Furthermore, levels are distributed throughout almost all the entire nominal intensity range, i.e., the images have sparse histograms of intensity levels. Image compression algorithms are based on sophisticated assumptions as to characteristics of the images they process. Sparse histogram is clearly different from what is expected by lossless image compression algorithm, both in case of predictive and of transform coding. To improve the compression ratios of such images, a method of histogram packing was recently introduced. The method is found to be effective, however, the research was done for low bit depth images. In this paper, we investigate effects of packing histograms of high bit depth medical images. We analyze an off-line packing method and find it to be highly effective. The off-line packing requires the information, describing how to expand the histogram after decompressing an image, to be encoded along with the compressed image. We present an efficient method of encoding this information. Experiments are performed for CALIC, JPEG2000, and JPEG-LS. The effects of packing histograms on the compression ratios of tested algorithms are, for all the tested algorithms, very similar. The average compression ratio improvement obtained for the CR, CT, and MR images is about 15%, 42%, and 52% respectively.

  15. Comparative gastrointestinal safety of weekly oral bisphosphonates

    PubMed Central

    Katz, J. N.; Brookhart, M. A.; Stürmer, T.; Stedman, M. R.; Levin, R.; Solomon, D. H.

    2012-01-01

    Summary Weekly bisphosphonates are the primary agents used to treat osteoporosis. Although these agents are generally well tolerated, serious gastrointestinal adverse events, including hospitalization for gastrointestinal bleed, may arise. We compared the gastrointestinal safety between weekly alendronate and weekly risedronate and found no important difference between new users of these agents. Introduction Weekly bisphosphonates are the primary agents prescribed for osteoporosis. We examined the comparative gastrointestinal safety between weekly bisphosphonates. Methods We studied new users of weekly alendronate and weekly risedronate from June 2002 to August 2005 among enrollees in a state-wide pharmaceutical benefit program for seniors. Our primary outcome was hospitalization for upper gastrointestinal bleed. Secondary outcomes included outpatient diagnoses for upper gastrointestinal disease, symptoms, endoscopic procedures, use of gastroprotective agents, and switching between therapies. We used Cox proportional hazard models to compare outcomes between agents within 120 days of treatment initiation, adjusting for propensity score quintiles. We also examined composite safety outcomes and stratified results by age and prior gastrointestinal history. Results A total of 10,420 new users were studied, mean age=79 years (SD, 6.9), and 95% women. We observed 31 hospitalizations for upper gastrointestinal bleed (0.91 per 100 person-years) within 120 days of treatment initiation. Adjusting for covariates, there was no difference in hospitalization for upper gastrointestinal bleed among those treated with risedronate compared with alendronate (HR, 1.12; 95%CI, 0.55 to 2.28). Risedronate switching rates were lower; otherwise, no differences were observed for secondary or composite outcomes. Conclusions We found no important difference in gastrointestinal safety between weekly oral bisphosphonates. PMID:19266138

  16. Compressing the inert doublet model

    NASA Astrophysics Data System (ADS)

    Blinov, Nikita; Kozaczuk, Jonathan; Morrissey, David E.; de la Puente, Alejandro

    2016-02-01

    The inert doublet model relies on a discrete symmetry to prevent couplings of the new scalars to Standard Model fermions. This stabilizes the lightest inert state, which can then contribute to the observed dark matter density. In the presence of additional approximate symmetries, the resulting spectrum of exotic scalars can be compressed. Here, we study the phenomenological and cosmological implications of this scenario. We derive new limits on the compressed inert doublet model from LEP, and outline the prospects for exclusion and discovery of this model at dark matter experiments, the LHC, and future colliders.

  17. Compressing the Inert Doublet Model

    SciTech Connect

    Blinov, Nikita; Morrissey, David E.; de la Puente, Alejandro

    2015-10-29

    The Inert Doublet Model relies on a discrete symmetry to prevent couplings of the new scalars to Standard Model fermions. We found that this stabilizes the lightest inert state, which can then contribute to the observed dark matter density. In the presence of additional approximate symmetries, the resulting spectrum of exotic scalars can be compressed. Here, we study the phenomenological and cosmological implications of this scenario. Furthermore, we derive new limits on the compressed Inert Doublet Model from LEP, and outline the prospects for exclusion and discovery of this model at dark matter experiments, the LHC, and future colliders.

  18. Data compression in digitized lines

    SciTech Connect

    Thapa, K. )

    1990-04-01

    The problem of data compression is very important in digital photogrammetry, computer assisted cartography, and GIS/LIS. In addition, it is also applicable in many other fields such as computer vision, image processing, pattern recognition, and artificial intelligence. Consequently, there are many algorithms available to solve this problem but none of them are considered to be satisfactory. In this paper, a new method of finding critical points in a digitized curve is explained. This technique, based on the normalized symmetric scattered matrix, is good for both critical points detection and data compression. In addition, the critical points detected by this algorithm are compared with those by zero-crossings. 8 refs.

  19. Data compression in digitized lines

    NASA Technical Reports Server (NTRS)

    Thapa, Khagendra

    1990-01-01

    The problem of data compression is very important in digital photogrammetry, computer assisted cartography, and GIS/LIS. In addition, it is also applicable in many other fields such as computer vision, image processing, pattern recognition, and artificial intelligence. Consequently, there are many algorithms available to solve this problem but none of them are considered to be satisfactory. In this paper, a new method of finding critical points in a digitized curve is explained. This technique, based on the normalized symmetric scattered matrix, is good for both critical points detection and data compression. In addition, the critical points detected by this algorithm are compared with those by zero-crossings.

  20. Data compression for satellite images

    NASA Technical Reports Server (NTRS)

    Chen, P. H.; Wintz, P. A.

    1976-01-01

    An efficient data compression system is presented for satellite pictures and two grey level pictures derived from satellite pictures. The compression techniques take advantages of the correlation between adjacent picture elements. Several source coding methods are investigated. Double delta coding is presented and shown to be the most efficient. Both predictive differential quantizing technique and double delta coding can be significantly improved by applying a background skipping technique. An extension code is constructed. This code requires very little storage space and operates efficiently. Simulation results are presented for various coding schemes and source codes.

  1. Unusual self-similar spherical compression: theory and implementations

    NASA Astrophysics Data System (ADS)

    Gerin-Roze, Jean

    2005-07-01

    We are showing a family of spherical implosions involving high compression rate. It depends on two parameters and we can work all of it out. I Theory What is an ``unusual self-similar compression law''? Such a law is characterized by a classical self-similar law initiated by a convergent shock (cf Lazarus and Richtmyer LA6823MS-1977) followed by centred compression waves. We will explain completely the implosion given by this law. II Implementations We will apply such a law to a DT sphere (m=1.5 mug and ?0=0.003 g/cm3). We will describe the thermodynamical conditions obtained this way. Then we will compare these results to those obtained with a 1D hydrodynamical computational code under different hypotheses regarding outside conditions and gas EOS. We will discuss the agreement between model and computational code under the different hypotheses. III Conclusion Such a flow may be worth using: -It gives an accurate hydrodynamical benchmark with the difficult problem of spherical shock convergence. -It can be used to define laser experiments where very compressed matter is needed (spectroscopy experiments, thermonuclear ignition...). Indeed, it allows to build an optimized compression law for each problem. An interesting extension of this work will be to add a second medium surrounding the gas. By using the characteristic curves, we could obtain the outside conditions (pressure or speed versus time) for this more realistic geometry.

  2. Compressive sensing based video object compression schemes for surveillance systems

    NASA Astrophysics Data System (ADS)

    Narayanan, Sathiya; Makur, Anamitra

    2015-03-01

    In some surveillance videos, successive frames exhibit correlation in the sense that only a small portion changes (object motion). If the foreground moving objects are segmented from the background they can be coded independently requiring far fewer bits compared to frame-based coding. Huang et al proposed a Compressive Sensing (CS) based Video Object Error Coding (CS-VOEC) where the objects are segmented and coded via motion estimation and compensation. Since motion estimation might be computationally intensive, encoder can be kept simple by performing motion estimation the decoder rather than at the encoder. We propose a novel CS based Video Object Compression (CS-VOC) technique having a simple encoder in which the sensing mechanism is applied directly on the segmented moving objects using a CS matrix. At the decoder, the object motion is first estimated so that a CS reconstruction algorithm can efficiently recover the sparse motion-compensated video object error. In addition to simple encoding, simulation results show our coding scheme performs on par with the state-of-the-art CS based video object error coding scheme. If the object segmentation requires more computations, we propose to deploy a distributed CS framework called Distributed Compressive Video Sensing based Video Object Compression (DCVS-VOC) wherein the object segmentation is done only for key frames.

  3. Impact of lossy compression on diagnostic accuracy of radiographs for periapical lesions

    NASA Technical Reports Server (NTRS)

    Eraso, Francisco E.; Analoui, Mostafa; Watson, Andrew B.; Rebeschini, Regina

    2002-01-01

    OBJECTIVES: The purpose of this study was to evaluate the lossy Joint Photographic Experts Group compression for endodontic pretreatment digital radiographs. STUDY DESIGN: Fifty clinical charge-coupled device-based, digital radiographs depicting periapical areas were selected. Each image was compressed at 2, 4, 8, 16, 32, 48, and 64 compression ratios. One root per image was marked for examination. Images were randomized and viewed by four clinical observers under standardized viewing conditions. Each observer read the image set three times, with at least two weeks between each reading. Three pre-selected sites per image (mesial, distal, apical) were scored on a five-scale score confidence scale. A panel of three examiners scored the uncompressed images, with a consensus score for each site. The consensus score was used as the baseline for assessing the impact of lossy compression on the diagnostic values of images. The mean absolute error between consensus and observer scores was computed for each observer, site, and reading session. RESULTS: Balanced one-way analysis of variance for all observers indicated that for compression ratios 48 and 64, there was significant difference between mean absolute error of uncompressed and compressed images (P <.05). After converting the five-scale score to two-level diagnostic values, the diagnostic accuracy was strongly correlated (R (2) = 0.91) with the compression ratio. CONCLUSION: The results of this study suggest that high compression ratios can have a severe impact on the diagnostic quality of the digital radiographs for detection of periapical lesions.

  4. Local fluorouracil chemotherapy interferes with neural and behavioral recovery after brain tumor-like mass compression.

    PubMed

    Yang, Hongyan; Zhang, Xuepeng; Chopp, Michael; Jiang, Feng; Schallert, Timothy

    2006-09-15

    In this study, we investigated the impact of intracerebral delivery of chemotherapy on functional recovery from focal cortical tissue displacement, characteristic of brain tumors. Unilateral focal brain compression was induced by epidural implantation of an inverted hemisphere-shaped bead over the sensorimotor cortex. Microinjections of a total of 1mg chemoagent fluorouracil or the same volume of saline were made into the compressed cortex. Behavioral tests of forelimb sensorimotor function were conducted during 4 weeks' observation. Rats subjected to any of the three types of lesions, saline microinjection plus cortical compression, chemoagent microinjection alone, or chemoagent microinjection combined with cortical compression, demonstrated significant behavioral deficits in several sensorimotor tasks, compared with saline-microinjected control animals. In placing tests, behavioral deficits elicited by each single treatment were worsened by combined treatment with chemoagent microinjection and focal cortical compression. Concurrently, local delivery of chemoagent into the compressed cortex induced increased cortical tissue loss, necrosis and apoptosis. These data indicate that local chemotherapy exacerbates compression-induced neurological impairment, and a model of controlled focal cortical compression may provide a valuable means to improve anti-cancer therapeutic designs with reduced deterioration of brain function. PMID:16713638

  5. Comparison on accuracy of image matching between lossy JPEG compression and lossy JPEG 2000 compression

    NASA Astrophysics Data System (ADS)

    Matsuoka, Ryuji; Sone, Mitsuo; Sudo, Noboru; Yokotsuka, Hideyo; Shirai, Naoki

    2013-10-01

    This paper reports an experiment conducted in order to compare lossy JPEG compression and lossy JPEG 2000 compression on the accuracy of image matching. The experiment has been conducted by using 54 color images of diverse textures and diverse tones of color on the assumption that image matching utilizes a pair of images reconstructed from image data which are lossily compressed in an ordinary digital camera. Lossy JPEG compression has been executed with a set of compression parameters utilized in a digital camera Canon EOS 20D, while lossy JPEG 2000 compression has been executed in the way as the file size of a piece of JPEG 2000 compressed image data is the same file size of the corresponding JPEG compressed image data. Moreover, we have prepared another set of JPEG and JPEG 2000 compressed image data which are lossily compressed with the compression ratio expected for an ordinary color image when it is compressed in the EOS 20D. When the file size of a piece of JPEG 2000 compressed image data is the same as that of a piece of JPEG compressed image data, the experiment results clearly show that the compression performance of JPEG 2000 compression would be superior to that of JPEG compression on image quality as to pixel value in RGB color space. On the contrary, the results do not necessarily indicate that JPEG 2000 compression would be able to provide more accurate matching results than JPEG compression.

  6. The compressive stiffness of human pediatric heads.

    PubMed

    Loyd, Andre Matthew; Nightingale, Roger W; Luck, Jason F; Song, Yin; Fronheiser, Lucy; Cutcliffe, Hattie; Myers, Barry S; Dale Bass, Cameron R

    2015-11-01

    Head injury is a persistent and costly problem for both children and adults. Globally, approximately 10 million people are hospitalized each year for head injuries. Knowing the structural properties of the head is important for modeling the response of the head in impact, and for providing insights into mechanisms of head injury. Hence, the goal of this study was to measure the sub-injurious structural stiffness of whole pediatric heads. 12 cadaveric pediatric (20-week-gestation to 16 years old) heads were tested in a battery of viscoelastic compression tests. The heads were compressed in both the lateral and anterior-posterior directions to 5% of gauge length at normalized deformation rates of 0.0005/s, 0.01/s, 0.1/s, and 0.3/s. Because of the non-linear nature of the response, linear regression models were used to calculate toe region (<2.5%) and elastic region (>2.5%) stiffness separately so that meaningful comparisons could be made across rate, age, and direction. The results showed that age was the dominant factor in predicting the structural stiffness of the human head. A large and statistically significant increase in the stiffness of both the toe region and the elastic region was observed with increasing age (p<0.0001), but no significant difference was seen across direction or normalized deformation rate. The stiffness of the elastic region increased from as low as 5N/mm in the neonate to >4500N/mm in the 16 year old. The changes in stiffness with age may be attributed to the disappearance of soft sutures and the thickening of skull bones with age. PMID:26476760

  7. 30 CFR 77.412 - Compressed air systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Safeguards... shall be equipped with automatic pressure-relief valves, pressure gages, and drain valves. (b) Repairs involving the pressure system of compressors, receivers, or compressed-air-powered equipment shall not...

  8. 30 CFR 77.412 - Compressed air systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Safeguards... shall be equipped with automatic pressure-relief valves, pressure gages, and drain valves. (b) Repairs involving the pressure system of compressors, receivers, or compressed-air-powered equipment shall not...

  9. Mechanics of the Compression Wood Response: II. On the Location, Action, and Distribution of Compression Wood Formation.

    PubMed

    Archer, R R; Wilson, B F

    1973-04-01

    A new method for simulation of cross-sectional growth provided detailed information on the location of normal wood and compression wood increments in two tilted white pine (Pinus strobus L.) leaders. These data were combined with data on stiffness, slope, and curvature changes over a 16-week period to make the mechanical analysis. The location of compression wood changed from the under side to a flank side and then to the upper side of the leader as the geotropic stimulus decreased, owing to compression wood action. Its location shifted back to a flank side when the direction of movement of the leader reversed. A model for this action, based on elongation strains, was developed and predicted the observed curvature changes with elongation strains of 0.3 to 0.5%, or a maximal compressive stress of 60 to 300 kilograms per square centimeter. After tilting, new wood formation was distributed so as to maintain consistent strain levels along the leaders in bending under gravitational loads. The computed effective elastic moduli were about the same for the two leaders throughout the season. PMID:16658408

  10. 46 CFR 194.15-15 - Chemicals other than compressed gases.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Scientific Laboratory § 194.15-15 Chemicals other than compressed gases. Chemicals, including those listed in 49 CFR part 172, may be stored in small working quantities in the chemical laboratory. ... 46 Shipping 7 2013-10-01 2013-10-01 false Chemicals other than compressed gases. 194.15-15...

  11. 46 CFR 194.15-15 - Chemicals other than compressed gases.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Scientific Laboratory § 194.15-15 Chemicals other than compressed gases. Chemicals, including those listed in 49 CFR part 172, may be stored in small working quantities in the chemical laboratory. ... 46 Shipping 7 2010-10-01 2010-10-01 false Chemicals other than compressed gases. 194.15-15...

  12. 46 CFR 194.15-15 - Chemicals other than compressed gases.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Scientific Laboratory § 194.15-15 Chemicals other than compressed gases. Chemicals, including those listed in 49 CFR part 172, may be stored in small working quantities in the chemical laboratory. ... 46 Shipping 7 2012-10-01 2012-10-01 false Chemicals other than compressed gases. 194.15-15...

  13. 46 CFR 194.15-15 - Chemicals other than compressed gases.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Scientific Laboratory § 194.15-15 Chemicals other than compressed gases. Chemicals, including those listed in 49 CFR part 172, may be stored in small working quantities in the chemical laboratory. ... 46 Shipping 7 2011-10-01 2011-10-01 false Chemicals other than compressed gases. 194.15-15...

  14. 46 CFR 194.15-15 - Chemicals other than compressed gases.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Scientific Laboratory § 194.15-15 Chemicals other than compressed gases. Chemicals, including those listed in 49 CFR part 172, may be stored in small working quantities in the chemical laboratory. ... 46 Shipping 7 2014-10-01 2014-10-01 false Chemicals other than compressed gases. 194.15-15...

  15. 30 CFR 75.1106-4 - Use of liquefied and nonliquefied compressed gas cylinders; general requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-UNDERGROUND COAL MINES Fire Protection § 75.1106-4 Use of liquefied and nonliquefied compressed gas cylinders... gas cylinders; general requirements. 75.1106-4 Section 75.1106-4 Mineral Resources MINE SAFETY AND... compressed gas shall be trained and designated by the operator as qualified to perform the work to which...

  16. 30 CFR 75.1106-4 - Use of liquefied and nonliquefied compressed gas cylinders; general requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-UNDERGROUND COAL MINES Fire Protection § 75.1106-4 Use of liquefied and nonliquefied compressed gas cylinders... gas cylinders; general requirements. 75.1106-4 Section 75.1106-4 Mineral Resources MINE SAFETY AND... compressed gas shall be trained and designated by the operator as qualified to perform the work to which...

  17. 30 CFR 75.1106-4 - Use of liquefied and nonliquefied compressed gas cylinders; general requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-UNDERGROUND COAL MINES Fire Protection § 75.1106-4 Use of liquefied and nonliquefied compressed gas cylinders... gas cylinders; general requirements. 75.1106-4 Section 75.1106-4 Mineral Resources MINE SAFETY AND... compressed gas shall be trained and designated by the operator as qualified to perform the work to which...

  18. 30 CFR 75.1106-4 - Use of liquefied and nonliquefied compressed gas cylinders; general requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-UNDERGROUND COAL MINES Fire Protection § 75.1106-4 Use of liquefied and nonliquefied compressed gas cylinders... gas cylinders; general requirements. 75.1106-4 Section 75.1106-4 Mineral Resources MINE SAFETY AND... compressed gas shall be trained and designated by the operator as qualified to perform the work to which...

  19. 30 CFR 75.1106-4 - Use of liquefied and nonliquefied compressed gas cylinders; general requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-UNDERGROUND COAL MINES Fire Protection § 75.1106-4 Use of liquefied and nonliquefied compressed gas cylinders... gas cylinders; general requirements. 75.1106-4 Section 75.1106-4 Mineral Resources MINE SAFETY AND... compressed gas shall be trained and designated by the operator as qualified to perform the work to which...

  20. Fecal Impaction Causing Pelvic Venous Compression and Edema

    PubMed Central

    Naramore, Sara; Aziz, Faisal; Alexander, Chandran Paul; Methratta, Sosamma; Cilley, Robert; Rocourt, Dorothy

    2015-01-01

    Chronic constipation is a common condition which may result in fecal impaction. A 13-year-old male with chronic constipation and encopresis presented with fecal impaction for three weeks. The impaction caused abdominal pain, distension, encopresis, and decreased oral intake. He was found in severe distress with non-pitting edema of his feet and ankles along with perineal edema. The pedal edema worsened after receiving a fluid bolus, so concern arose for venous compression or a thrombus. A Duplex Ultrasound demonstrated changes in the venous waveforms of the bilateral external iliac and common femoral veins without thrombosis. Manual disimpaction and polyethylene glycol 3350 with electrolytes resolved the pedal and perineal edema. Four months later, he had soft bowel movements without recurrence of the edema. A repeat Duplex Ultrasound was normal. We present a child in whom severe fecal impaction caused pelvic venous compression resulting in bilateral pedal and perineal edema. PMID:26500749

  1. Fecal Impaction Causing Pelvic Venous Compression and Edema.

    PubMed

    Naramore, Sara; Aziz, Faisal; Alexander, Chandran Paul; Methratta, Sosamma; Cilley, Robert; Rocourt, Dorothy

    2015-09-28

    Chronic constipation is a common condition which may result in fecal impaction. A 13-year-old male with chronic constipation and encopresis presented with fecal impaction for three weeks. The impaction caused abdominal pain, distension, encopresis, and decreased oral intake. He was found in severe distress with non-pitting edema of his feet and ankles along with perineal edema. The pedal edema worsened after receiving a fluid bolus, so concern arose for venous compression or a thrombus. A Duplex Ultrasound demonstrated changes in the venous waveforms of the bilateral external iliac and common femoral veins without thrombosis. Manual disimpaction and polyethylene glycol 3350 with electrolytes resolved the pedal and perineal edema. Four months later, he had soft bowel movements without recurrence of the edema. A repeat Duplex Ultrasound was normal. We present a child in whom severe fecal impaction caused pelvic venous compression resulting in bilateral pedal and perineal edema. PMID:26500749

  2. Lossless compression of JPEG2000 whole slide images is not required for diagnostic virtual microscopy.

    PubMed

    Kalinski, Thomas; Zwönitzer, Ralf; Grabellus, Florian; Sheu, Sien-Yi; Sel, Saadettin; Hofmann, Harald; Roessner, Albert

    2011-12-01

    The use of lossy compression in medical imaging is controversial, although it is inevitable to reduce large data amounts. In contrast with lossy compression, lossless compression does not impair image quality. In addition to our previous studies, we evaluated virtual 3-dimensional microscopy using JPEG2000 whole slide images of gastric biopsy specimens with or without Helicobacter pylori gastritis using lossless compression (1:1) or lossy compression with different compression levels: 5:1, 10:1, and 20:1. The virtual slides were diagnosed in a blinded manner by 3 pathologists using the updated Sydney classification. The results showed no significant differences in the diagnosis of H pylori between the different levels of compression in virtual microscopy. We assume that lossless compression is not required for diagnostic virtual microscopy. The limits of lossy compression in virtual microscopy without a loss of diagnostic quality still need to be determined. Analogous to the processes in radiology, recommendations for the use of lossy compression in diagnostic virtual microscopy have to be worked out by pathology societies. PMID:22095374

  3. Perceptually lossy compression of documents

    NASA Astrophysics Data System (ADS)

    Beretta, Giordano B.; Bhaskaran, Vasudev; Konstantinides, Konstantinos; Natarajan, Balas R.

    1997-06-01

    The main cost of owning a facsimile machine consists of the telephone charges for the communications, thus short transmission times are a key feature for facsimile machines. Similarly, on a packet-routed service such as the Internet, a low number of packets is essential to avoid operator wait times. Concomitantly, the user expectations have increased considerably. In facsimile, the switch from binary to full color increases the data size by a factor of 24. On the Internet, the switch from plain text American Standard Code for Information Interchange (ASCII) encoded files to files marked up in the Hypertext Markup Language (HTML) with ample embedded graphics has increased the size of transactions by several orders of magnitude. A common compressing method for raster files in these applications in the Joint Photographic Experts Group (JPEG) method, because efficient implementations are readily available. In this method the implementors design the discrete quantization tables (DQT) and the Huffman tables (HT) to maximize the compression factor while maintaining the introduced artifacts at the threshold of perceptual detectability. Unfortunately the achieved compression rates are unsatisfactory for applications such as color facsimile and World Wide Web (W3) browsing. We present a design methodology for image-independent DQTs that while producing perceptually lossy data, does not impair the reading performance of users. Combined with a text sharpening algorithm that compensates for scanning device limitations, the methodology presented in this paper allows us to achieve compression ratios near 1:100.

  4. Compression testing of flammable liquids

    NASA Technical Reports Server (NTRS)

    Briles, O. M.; Hollenbaugh, R. P.

    1979-01-01

    Small cylindrical test chamber determines catalytic effect of given container material on fuel that might contribute to accidental deflagration or detonation below expected temperature under adiabatic compression. Device is useful to producers and users of flammable liquids and to safety specialists.

  5. Compressive passive millimeter wave imager

    DOEpatents

    Gopalsami, Nachappa; Liao, Shaolin; Elmer, Thomas W; Koehl, Eugene R; Heifetz, Alexander; Raptis, Apostolos C

    2015-01-27

    A compressive scanning approach for millimeter wave imaging and sensing. A Hadamard mask is positioned to receive millimeter waves from an object to be imaged. A subset of the full set of Hadamard acquisitions is sampled. The subset is used to reconstruct an image representing the object.

  6. COMPRESSIBLE FLOW, ENTRAINMENT, AND MEGAPLUME

    EPA Science Inventory

    It is generally believed that low Mach number, i.e., low-velocity, flow may be assumed to be incompressible flow. Under steady-state conditions, an exact equation of continuity may then be used to show that such flow is non-divergent. However, a rigorous, compressible fluid-dynam...

  7. Teaching Time-Space Compression

    ERIC Educational Resources Information Center

    Warf, Barney

    2011-01-01

    Time-space compression shows students that geographies are plastic, mutable and forever changing. This paper justifies the need to teach this topic, which is rarely found in undergraduate course syllabi. It addresses the impacts of transportation and communications technologies to explicate its dynamics. In summarizing various conceptual…

  8. Teaching Time-Space Compression

    ERIC Educational Resources Information Center

    Warf, Barney

    2011-01-01

    Time-space compression shows students that geographies are plastic, mutable and forever changing. This paper justifies the need to teach this topic, which is rarely found in undergraduate course syllabi. It addresses the impacts of transportation and communications technologies to explicate its dynamics. In summarizing various conceptual…

  9. Culture: Copying, Compression, and Conventionality

    ERIC Educational Resources Information Center

    Tamariz, Mónica; Kirby, Simon

    2015-01-01

    Through cultural transmission, repeated learning by new individuals transforms cultural information, which tends to become increasingly compressible (Kirby, Cornish, & Smith, 2008; Smith, Tamariz, & Kirby, 2013). Existing diffusion chain studies include in their design two processes that could be responsible for this tendency: learning…

  10. A programmable image compression system

    NASA Technical Reports Server (NTRS)

    Farrelle, Paul M.

    1989-01-01

    A programmable image compression system which has the necessary flexibility to address diverse imaging needs is described. It can compress and expand single frame video images (monochrome or color) as well as documents and graphics (black and white or color) for archival or transmission applications. Through software control, the compression mode can be set for lossless or controlled quality coding; the image size and bit depth can be varied; and the image source and destination devices can be readily changed. Despite the large combination of image data types, image sources, and algorithms, the system provides a simple consistent interface to the programmer. This system (OPTIPAC) is based on the TITMS320C25 digital signal processing (DSP) chip and has been implemented as a co-processor board for an IBM PC-AT compatible computer. The underlying philosophy can readily be applied to different hardware platforms. By using multiple DSP chips or incorporating algorithm specific chips, the compression and expansion times can be significantly reduced to meet performance requirements.

  11. Culture: Copying, Compression, and Conventionality

    ERIC Educational Resources Information Center

    Tamariz, Mónica; Kirby, Simon

    2015-01-01

    Through cultural transmission, repeated learning by new individuals transforms cultural information, which tends to become increasingly compressible (Kirby, Cornish, & Smith, 2008; Smith, Tamariz, & Kirby, 2013). Existing diffusion chain studies include in their design two processes that could be responsible for this tendency: learning…

  12. Device Assists Cardiac Chest Compression

    NASA Technical Reports Server (NTRS)

    Eichstadt, Frank T.

    1995-01-01

    Portable device facilitates effective and prolonged cardiac resuscitation by chest compression. Developed originally for use in absence of gravitation, also useful in terrestrial environments and situations (confined spaces, water rescue, medical transport) not conducive to standard manual cardiopulmonary resuscitation (CPR) techniques.

  13. Direct compression properties of chitin and chitosan.

    PubMed

    Mir, Viviana García; Heinämäki, Jyrki; Antikainen, Osmo; Revoredo, Ofelia Bilbao; Colarte, Antonio Iraizoz; Nieto, Olga Maria; Yliruusi, Jouko

    2008-08-01

    Deformation and compaction properties of native amino poly-saccharides chitin and chitosan were studied and compared with those obtained with established pharmaceutical direct compression excipients. An instrumented single-punch tablet machine was used for tablet compaction. The following compression parameters were evaluated: a ratio of crushing strength and compression pressure, plasticity and elasticity factor (PF and EF), tensile strength and R-value. Chitin and chitosan were found to have a marked tendency to plastic deformation, and both showed a good compression behaviour compared with the other direct compression excipients including microcrystalline cellulose. It is concluded that chitin and chitosan are potential co-excipients for direct compression applications. PMID:18406116

  14. Image compression in morphometry studies requiring 21 CFR Part 11 compliance: procedure is key with TIFFs and various JPEG compression strengths.

    PubMed

    Tengowski, Mark W

    2004-01-01

    This study aims to compare the integrity and reproducibility of measurements created from uncompressed and compressed digital images in order to implement compliance with 21 CFR Part 11 for image analysis studies executed using 21 CFR Part 58 compliant capture systems. Images of a 400-mesh electron microscope grid and H&E stained rat liver tissue were captured on an upright microscope with digital camera using commercially available analysis software. Digital images were stored as either uncompressed TIFFs or in one of five different levels of JPEG compression. The grid images were analyzed with automatic detection of bright objects while the liver images were segmented using color cube-based morphometry techniques, respectively, using commercially-available image analysis software. When comparing the feature-extracted measurements from the TIFF uncompressed to the JPEG compressed images, the data suggest that JPEG compression does not alter the accuracy or reliability to reproduce individual data point measurements in all but the highest compression levels. There is, however, discordance if the initial measure was obtained with a TIFF format and subsequently saved as one of the JPEG levels, suggesting that the use of compression must precede feature extraction. It is a common practice in software packages to work with TIFF uncompressed images. However, this study suggests that the use of JPEG compression as part of the analysis work flow was an acceptable practice for these images and features. Investigators applying image file compression to other organ images will need to validate the utility of image compression in their work flow. A procedure to digitally acquire and JPEG compress images prior to image analysis has the potential to reduce file archiving demands without compromising reproducibility of data. PMID:15200165

  15. Conductivity enhancement of multiwalled carbon nanotube thin film via thermal compression method

    PubMed Central

    2014-01-01

    For the first time, the thermal compression method is applied to effectively enhance the electrical conductivity of carbon nanotube thin films (CNTFs). With the assistance of heat and pressure on the CNTFs, the neighbor multiwalled carbon nanotubes (CNTs) start to link with each other, and then these separated CNTs are twined into a continuous film while the compression force, duration, and temperature are quite enough for the reaction. Under the compression temperature of 400°C and the compression force of 100 N for 50 min, the sheet resistance can be reduced from 17 to 0.9 k Ω/sq for the CNTFs with a thickness of 230 nm. Moreover, the effects of compression temperature and the duration of thermal compression on the conductivity of CNTF are also discussed in this work. PMID:25232300

  16. Adaptive Multi-Rate Compression Effects on Vowel Analysis

    PubMed Central

    Ireland, David; Knuepffer, Christina; McBride, Simon J.

    2015-01-01

    Signal processing on digitally sampled vowel sounds for the detection of pathological voices has been firmly established. This work examines compression artifacts on vowel speech samples that have been compressed using the adaptive multi-rate codec at various bit-rates. Whereas previous work has used the sensitivity of machine learning algorithm to test for accuracy, this work examines the changes in the extracted speech features themselves and thus report new findings on the usefulness of a particular feature. We believe this work will have potential impact for future research on remote monitoring as the identification and exclusion of an ill-defined speech feature that has been hitherto used, will ultimately increase the robustness of the system. PMID:26347863

  17. The CCSDS Lossless Data Compression Algorithm for Space Applications

    NASA Technical Reports Server (NTRS)

    Yeh, Pen-Shu; Day, John H. (Technical Monitor)

    2001-01-01

    In the late 80's, when the author started working at the Goddard Space Flight Center (GSFC) for the National Aeronautics and Space Administration (NASA), several scientists there were in the process of formulating the next generation of Earth viewing science instruments, the Moderate Resolution Imaging Spectroradiometer (MODIS). The instrument would have over thirty spectral bands and would transmit enormous data through the communications channel. This was when the author was assigned the task of investigating lossless compression algorithms for space implementation to compress science data in order to reduce the requirement on bandwidth and storage.

  18. A PDF closure model for compressible turbulent chemically reacting flows

    NASA Technical Reports Server (NTRS)

    Kollmann, W.

    1992-01-01

    The objective of the proposed research project was the analysis of single point closures based on probability density function (pdf) and characteristic functions and the development of a prediction method for the joint velocity-scalar pdf in turbulent reacting flows. Turbulent flows of boundary layer type and stagnation point flows with and without chemical reactions were be calculated as principal applications. Pdf methods for compressible reacting flows were developed and tested in comparison with available experimental data. The research work carried in this project was concentrated on the closure of pdf equations for incompressible and compressible turbulent flows with and without chemical reactions.

  19. Simulation of Inviscid Compressible Multi-Phase Flow with Condensation

    NASA Technical Reports Server (NTRS)

    Kelleners, Philip

    2003-01-01

    Condensation of vapours in rapid expansions of compressible gases is investigated. In the case of high temperature gradients the condensation will start at conditions well away from thermodynamic equilibrium of the fluid. In those cases homogeneous condensation is dominant over heterogeneous condensation. The present work is concerned with development of a simulation tool for computation of high speed compressible flows with homogeneous condensation. The resulting ow solver should preferably be accurate and robust to be used for simulation of industrial flows in general geometries.

  20. On the creep deformation of nickel foams under compression

    NASA Astrophysics Data System (ADS)

    Burteau, Anthony; Bartout, Jean-Dominique; Bienvenu, Yves; Forest, Samuel

    2014-10-01

    A finite-element computational strategy is developed to study the viscoplastic deformation mechanisms at work in a nickel foam sample under compression creep. The constitutive law for pure nickel accounts for both diffusional and dislocation creep mechanisms. The finite-element results show the competition between both mechanisms due to the strong heterogeneity of the stress distribution in the foam. The initiation of the viscoplastic buckling phenomenon leading to cell crushing in tertiary creep is illustrated. The overall model prediction is compared to the results of compression creep tests performed in vacuo at 900 °C. xml:lang="fr"

  1. Studies of fiber-matrix adhesion on compression strength

    NASA Technical Reports Server (NTRS)

    Bascom, Willard D.; Nairn, John A.; Boll, D. J.

    1991-01-01

    A study was initiated on the effect of the matrix polymer and the fiber matrix bond strength of carbon fiber polymer matrix composites. The work includes tests with micro-composites, single ply composites, laminates, and multi-axial loaded cylinders. The results obtained thus far indicate that weak fiber-matrix adhesion dramatically reduces 0 degree compression strength. Evidence is also presented that the flaws in the carbon fiber that govern compression strength differ from those that determine fiber tensile strength. Examination of post-failure damage in the single ply tests indicates kink banding at the crack tip.

  2. The Compressibility Burble and the Effect of Compressibility on Pressures and Forces Acting on a Airfoil

    NASA Technical Reports Server (NTRS)

    Stack, John; Lindsey, W F; Littell, Robert E

    1939-01-01

    Simultaneous air-flow photographs and pressure-distribution measurements were made of the NACA 4412 airfoil at high speeds to determine the physical nature of the compressibility burble. The tests were conducted in the NACA 24-inch high-speed wind tunnel. The flow photographs were obtained by the Schlieren method and the pressures were simultaneously measured for 54 stations in the 5-inch-chord airfoil by means of a multiple-tube manometer. Following the general program, a few measurements of total-pressure loss in the wake of the airfoil at high speeds were made to illustrate the magnitude of the losses involved and the extent of the disturbed region; and, finally, in order to relate this work to earlier force-test data, a force test of a 5-inch-chord NACA 4412 airfoil was made. The results show the general nature of the phenomenon known as the compressibility burble. The source of the increased drag is shown to be a compression shock that occurs on the airfoil as its speed approaches the speed of sound. Finally, it is indicated that considerable experimentation is needed in order to understand the phenomenon completely.

  3. Poster Presentations: Turning a Lab of the Week into a Culminating Experience

    ERIC Educational Resources Information Center

    Logan, Jennifer L.; Quin~ones, Rosalynn; Sunderland, Deborah P.

    2015-01-01

    An assignment incorporating posters into a second-year analytical chemistry lab is described. Students work in groups and are assigned one of the application-themed weekly laboratories as a topic. Course data acquired for these weekly laboratories are compiled into spreadsheets that the poster group then analyzes to present in an on-campus poster…

  4. 29 CFR 3.3 - Weekly statement with respect to payment of wages.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 1 2012-07-01 2012-07-01 false Weekly statement with respect to payment of wages. 3.3 Section 3.3 Labor Office of the Secretary of Labor CONTRACTORS AND SUBCONTRACTORS ON PUBLIC BUILDING OR PUBLIC WORK FINANCED IN WHOLE OR IN PART BY LOANS OR GRANTS FROM THE UNITED STATES § 3.3 Weekly...

  5. 29 CFR 3.3 - Weekly statement with respect to payment of wages.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 1 2013-07-01 2013-07-01 false Weekly statement with respect to payment of wages. 3.3 Section 3.3 Labor Office of the Secretary of Labor CONTRACTORS AND SUBCONTRACTORS ON PUBLIC BUILDING OR PUBLIC WORK FINANCED IN WHOLE OR IN PART BY LOANS OR GRANTS FROM THE UNITED STATES § 3.3 Weekly...

  6. 29 CFR 3.3 - Weekly statement with respect to payment of wages.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 1 2014-07-01 2013-07-01 true Weekly statement with respect to payment of wages. 3.3 Section 3.3 Labor Office of the Secretary of Labor CONTRACTORS AND SUBCONTRACTORS ON PUBLIC BUILDING OR PUBLIC WORK FINANCED IN WHOLE OR IN PART BY LOANS OR GRANTS FROM THE UNITED STATES § 3.3 Weekly...

  7. Poster Presentations: Turning a Lab of the Week into a Culminating Experience

    ERIC Educational Resources Information Center

    Logan, Jennifer L.; Quin~ones, Rosalynn; Sunderland, Deborah P.

    2015-01-01

    An assignment incorporating posters into a second-year analytical chemistry lab is described. Students work in groups and are assigned one of the application-themed weekly laboratories as a topic. Course data acquired for these weekly laboratories are compiled into spreadsheets that the poster group then analyzes to present in an on-campus poster…

  8. 29 CFR 3.3 - Weekly statement with respect to payment of wages.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Weekly statement with respect to payment of wages. 3.3 Section 3.3 Labor Office of the Secretary of Labor CONTRACTORS AND SUBCONTRACTORS ON PUBLIC BUILDING OR PUBLIC WORK FINANCED IN WHOLE OR IN PART BY LOANS OR GRANTS FROM THE UNITED STATES § 3.3 Weekly...

  9. 29 CFR 3.3 - Weekly statement with respect to payment of wages.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 1 2011-07-01 2011-07-01 false Weekly statement with respect to payment of wages. 3.3 Section 3.3 Labor Office of the Secretary of Labor CONTRACTORS AND SUBCONTRACTORS ON PUBLIC BUILDING OR PUBLIC WORK FINANCED IN WHOLE OR IN PART BY LOANS OR GRANTS FROM THE UNITED STATES § 3.3 Weekly...

  10. Effects of 8-Week Training on Aerobic Capacity and Swimming Performance of Boys Aged 12 Years

    ERIC Educational Resources Information Center

    Zarzeczny, Ryszard; Kuberski, Mariusz; Deska, Agnieszka; Zarzeczna, Dorota; Rydz, Katarzyna; Lewandowska, Anna; Balchanowski, Tomasz; Bosiacki, Janusz

    2011-01-01

    Study aim: To assess the effects of 8-week endurance training in swimming on work capacity of boys aged 12 years. Material and methods: The following groups of schoolboys aged 12 years were studied: untrained control (UC; n = 14) and those training swimming for two years. The latter ones were subjected to 8-week training in classical style (CS; n…

  11. STAR WEEK: A Successful Campaign in Japan

    NASA Astrophysics Data System (ADS)

    Watanabe, Junichi

    2011-06-01

    A campaign of the Star Week, set as August 1 - 7, has been started in 1995 throughout various life-learning facilities. Astronomical facilities including planetariums, science museums, and public observatories has been participating in this campaign, together with amateur astronomers clubs or private observatories. More than 300 astronomical events such as star watching parties were coordinated for general public every year. The Star Week has been grown up to one of the most successful campaigns not only for for astronomy but also for basic sciences in Japan over this 15 years. In this paper, a brief history and the present status of the Star Week are introduced together with the with some statistics.

  12. Vehicle Technologies' Fact of the Week 2012

    SciTech Connect

    Davis, Stacy Cagle; Diegel, Susan W; Moore, Sheila A; Boundy, Robert Gary

    2013-02-01

    Each week the U.S. Department of Energy s Vehicle Technology Office (VTO) posts a Fact of the Week on their website: http://www1.eere.energy.gov/vehiclesandfuels/ . These Facts provide statistical information, usually in the form of charts and tables, on vehicle sales, fuel economy, gasoline prices, and other transportation-related trends. Each Fact is a stand-alone page that includes a graph, text explaining the significance of the data, the supporting information on which the graph was based, and the source of the data. A link to the current week s Fact is available on the VTO homepage, but older Facts are archived and still available at: http://www1.eere.energy.gov/vehiclesandfuels/facts/. This report is a compilation of the Facts that were posted during calendar year 2012. The Facts were written and prepared by staff in Oak Ridge National Laboratory's Center for Transportation Analysis.

  13. Vehicle Technologies Fact of the Week 2013

    SciTech Connect

    Davis, Stacy Cagle; Williams, Susan E; Moore, Sheila A; Boundy, Robert Gary

    2014-03-01

    Each week the U.S. Department of Energy s Vehicle Technology Office (VTO) posts a Fact of the Week on their website: http://www1.eere.energy.gov/vehiclesandfuels/ . These Facts provide statistical information, usually in the form of charts and tables, on vehicle sales, fuel economy, gasoline prices, and other transportation-related trends. Each Fact is a stand-alone page that includes a graph, text explaining the significance of the data, the supporting information on which the graph was based, and the source of the data. A link to the current week s Fact is available on the VTO homepage, but older Facts are archived and still available at: http://www1.eere.energy.gov/vehiclesandfuels/facts/. This report is a compilation of the Facts that were posted during calendar year 2013. The Facts were written and prepared by staff in Oak Ridge National Laboratory's Center for Transportation Analysis.

  14. Analytical and experimental study on complex compressed air pipe network

    NASA Astrophysics Data System (ADS)

    Gai, Yushou; Cai, Maolin; Shi, Yan

    2015-09-01

    To analyze the working characteristics of complex compressed air networks, numerical methods are widely used which are based on finite element technology or intelligent algorithms. However, the effectiveness of the numerical methods is limited. In this paper, to provide a new method to optimize the design and the air supply strategy of the complex compressed air pipe network, firstly, a novel method to analyze the topology structure of the compressed air flow in the pipe network is initially proposed. A matrix is used to describe the topology structure of the compressed air flow. Moreover, based on the analysis of the pressure loss of the pipe network, the relationship between the pressure and the flow of the compressed air is derived, and a prediction method of pressure fluctuation and air flow in a segment in a complex pipe network is proposed. Finally, to inspect the effectiveness of the method, an experiment with a complex network is designed. The pressure and the flow of airflow in the network are measured and studied. The results of the study show that, the predicted results with the proposed method have a good consistency with the experimental results, and that verifies the air flow prediction method of the complex pipe network. This research proposes a new method to analyze the compressed air network and a prediction method of pressure fluctuation and air flow in a segment, which can predicate the fluctuation of the pressure according to the flow of compressed air, and predicate the fluctuation of the flow according to the pressure in a segment of a complex pipe network.

  15. URe{sub 2}-A compressibility study of allotropic phases

    SciTech Connect

    Shukla, B. Shekar, N. V. Chandra Sahu, P. Ch.

    2014-04-24

    URe{sub 2} compound exists in two phases- orthorhombic and hexagonal. The hexagonal phase has been prepared using arc melting and annealingat 500°C for one week, whereas the orthorhombic phase was achieved by annealing the arc melted sample at a temperature 150°C for the same period. High pressure x-ray diffraction studies on these two allotropic forms of URe{sub 2} have been carried out up to ∼15GPa using a diamond anvil cell. Normal compression was observed without any kind of phase transformation; although there is a probability of transformation from the metastable hexagonal to itsstable orthorhombicphase under pressure.

  16. ADVANCED RECIPROCATING COMPRESSION TECHNOLOGY (ARCT)

    SciTech Connect

    Danny M. Deffenbaugh; Klaus Brun; Ralph E. Harris; J. Pete Harrell; Robert J. Mckee; J. Jeffrey Moore; Steven J. Svedeman; Anthony J. Smalley; Eugene L. Broerman; Robert A Hart; Marybeth G. Nored; Ryan S. Gernentz; Shane P. Siebenaler

    2005-12-01

    The U.S. natural gas pipeline industry is facing the twin challenges of increased flexibility and capacity expansion. To meet these challenges, the industry requires improved choices in gas compression to address new construction and enhancement of the currently installed infrastructure. The current fleet of installed reciprocating compression is primarily slow-speed integral machines. Most new reciprocating compression is and will be large, high-speed separable units. The major challenges with the fleet of slow-speed integral machines are: limited flexibility and a large range in performance. In an attempt to increase flexibility, many operators are choosing to single-act cylinders, which are causing reduced reliability and integrity. While the best performing units in the fleet exhibit thermal efficiencies between 90% and 92%, the low performers are running down to 50% with the mean at about 80%. The major cause for this large disparity is due to installation losses in the pulsation control system. In the better performers, the losses are about evenly split between installation losses and valve losses. The major challenges for high-speed machines are: cylinder nozzle pulsations, mechanical vibrations due to cylinder stretch, short valve life, and low thermal performance. To shift nozzle pulsation to higher orders, nozzles are shortened, and to dampen the amplitudes, orifices are added. The shortened nozzles result in mechanical coupling with the cylinder, thereby, causing increased vibration due to the cylinder stretch mode. Valve life is even shorter than for slow speeds and can be on the order of a few months. The thermal efficiency is 10% to 15% lower than slow-speed equipment with the best performance in the 75% to 80% range. The goal of this advanced reciprocating compression program is to develop the technology for both high speed and low speed compression that will expand unit flexibility, increase thermal efficiency, and increase reliability and integrity. Retrofit technologies that address the challenges of slow-speed integral compression are: (1) optimum turndown using a combination of speed and clearance with single-acting operation as a last resort; (2) if single-acting is required, implement infinite length nozzles to address nozzle pulsation and tunable side branch absorbers for 1x lateral pulsations; and (3) advanced valves, either the semi-active plate valve or the passive rotary valve, to extend valve life to three years with half the pressure drop. This next generation of slow-speed compression should attain 95% efficiency, a three-year valve life, and expanded turndown. New equipment technologies that address the challenges of large-horsepower, high-speed compression are: (1) optimum turndown with unit speed; (2) tapered nozzles to effectively reduce nozzle pulsation with half the pressure drop and minimization of mechanical cylinder stretch induced vibrations; (3) tunable side branch absorber or higher-order filter bottle to address lateral piping pulsations over the entire extended speed range with minimal pressure drop; and (4) semi-active plate valves or passive rotary valves to extend valve life with half the pressure drop. This next generation of large-horsepower, high-speed compression should attain 90% efficiency, a two-year valve life, 50% turndown, and less than 0.75 IPS vibration. This program has generated proof-of-concept technologies with the potential to meet these ambitious goals. Full development of these identified technologies is underway. The GMRC has committed to pursue the most promising enabling technologies for their industry.

  17. The CCDS Data Compression Recommendations: Development and Status

    NASA Technical Reports Server (NTRS)

    Yeh, Pen-Shu; Moury, Gilles; Armbruster, Philippe; Day, John H. (Technical Monitor)

    2002-01-01

    The Consultative Committee for Space Data Systems (CCSDS) has been engaging in recommending data compression standards for space applications. The first effort focused on a lossless scheme that was adopted in 1997. Since then, space missions benefiting from this recommendation range from deep space probes to near Earth observatories. The cost savings result not only from reduced onboard storage and reduced bandwidth, but also in ground archive of mission data. In many instances, this recommendation also enables more science data to be collected for added scientific value. Since 1998, the compression sub-panel of CCSDS has been investigating lossy image compression schemes and is currently working towards a common solution for a single recommendation. The recommendation will fulfill the requirements for remote sensing conducted on space platforms.

  18. Metal hydride hydrogen compression: Recent advances and future prospects

    DOE PAGESBeta

    Bowman, Jr., Robert C.; Yartys, Volodymyr A.; Lototskyy, Mykhaylo V.; Linkov, Vladimir; Grant, David; Stuart, Alastair; Eriksen, Jon; Denys, Roman

    2016-03-17

    Metal hydride (MH) thermal sorption compression is one of the more important applications of the metal hydrides. The present paper reviews recent advances in the field based on the analysis of the fundamental principles of this technology. The performances when boosting hydrogen pressure, along with two- and three-step compression units are analyzed. The paper includes also a theoretical modeling of a two-stage compressor aimed at both describing the performance of the experimentally studied systems, but, also, on their optimization and design of more advanced MH compressors. Business developments in the field are reviewed for the Norwegian company HYSTORSYS AS andmore » the South African Institute for Advanced Materials Chemistry. Finally, future prospects are outlined presenting the role of the metal hydride compression in the overall development of the hydrogen driven energy systems. Lastly, the work is based on the analysis of the development of the technology in Europe, USA and South Africa.« less

  19. Thermoacoustic compression based on alternating to direct gas flow conversion

    NASA Astrophysics Data System (ADS)

    Sun, D. M.; Wang, K.; Xu, Y.; Shen, Q.; Zhang, X. J.; Qiu, L. M.

    2012-05-01

    We present a remarkable thermoacoustically driven compression effect based on the conversion of gas flow from an alternating state to a direct state. The alternating gas flow is generated by the thermoacoustic effect in thermoacoustic engines, whereas direct gas flow is achieved by means of the flow rectification effect of check valves. A demonstrative thermoacoustic compressor consisting of two standing-wave thermoacoustic engines, two reservoirs, and three check valves is constructed for experimental investigation. With nitrogen as a working gas and an initial pressure of 2.4 MPa in all components, a usable pressure difference of 0.4 MPa is achieved, with the average gas pumping rate reaching 2.85 Nm3/h during the first 3 s of the compression process. The simple mechanical structure and thermally driven nature of the compressor show potential in gas compression, power generation, and refrigeration applications.

  20. [Midcarpal fusion using break-away compression screw].

    PubMed

    Maire, N; Facca, S; Gouzou, S; Liverneaux, P

    2012-02-01

    Indication of midcarpal fusion is SNAC or SLAC wrist grade 3. The main complication of circular plate (most common technique) is non-union. In this context, the purpose of our work was to propose the use of break-away compression screws to decrease the rate of non-union. Our series included ten patients. The fusion was fixed using two break-away compression screws (2mm diameter). No bone graft was used. As assessment, subjective (pain, Quick-DASH) and objective (strength, mobility) criteria were reviewed at follow-up. All the criteria were significantly improved after operation except mobility. Among the complications, we noticed one delayed bone-healing with a good outcome and a radiological consolidation. Midcarpal fusion by dorsal approach using break-away compression screws appears to us a technique of interest, not requiring a bone graft, with good cost effectiveness. PMID:22245281

  1. Joint segmentation and reconstruction of hyperspectral data with compressed measurements.

    PubMed

    Zhang, Qiang; Plemmons, Robert; Kittle, David; Brady, David; Prasad, Sudhakar

    2011-08-01

    This work describes numerical methods for the joint reconstruction and segmentation of spectral images taken by compressive sensing coded aperture snapshot spectral imagers (CASSI). In a snapshot, a CASSI captures a two-dimensional (2D) array of measurements that is an encoded representation of both spectral information and 2D spatial information of a scene, resulting in significant savings in acquisition time and data storage. The reconstruction process decodes the 2D measurements to render a three-dimensional spatio-spectral estimate of the scene and is therefore an indispensable component of the spectral imager. In this study, we seek a particular form of the compressed sensing solution that assumes spectrally homogeneous segments in the two spatial dimensions, and greatly reduces the number of unknowns, often turning the underdetermined reconstruction problem into one that is overdetermined. Numerical tests are reported on both simulated and real data representing compressed measurements. PMID:21833118

  2. Stem compression reversibly reduces phloem transport in Pinus sylvestris trees.

    PubMed

    Henriksson, Nils; Tarvainen, Lasse; Lim, Hyungwoo; Tor-Ngern, Pantana; Palmroth, Sari; Oren, Ram; Marshall, John; Näsholm, Torgny

    2015-10-01

    Manipulating tree belowground carbon (C) transport enables investigation of the ecological and physiological roles of tree roots and their associated mycorrhizal fungi, as well as a range of other soil organisms and processes. Girdling remains the most reliable method for manipulating this flux and it has been used in numerous studies. However, girdling is destructive and irreversible. Belowground C transport is mediated by phloem tissue, pressurized through the high osmotic potential resulting from its high content of soluble sugars. We speculated that phloem transport may be reversibly blocked through the application of an external pressure on tree stems. Thus, we here introduce a technique based on compression of the phloem, which interrupts belowground flow of assimilates, but allows trees to recover when the external pressure is removed. Metal clamps were wrapped around the stems and tightened to achieve a pressure theoretically sufficient to collapse the phloem tissue, thereby aiming to block transport. The compression's performance was tested in two field experiments: a (13)C canopy labelling study conducted on small Scots pine (Pinus sylvestris L.) trees [2-3?m tall, 3-7?cm diameter at breast height (DBH)] and a larger study involving mature pines (?15?m tall, 15-25?cm DBH) where stem respiration, phloem and root carbohydrate contents, and soil CO2 efflux were measured. The compression's effectiveness was demonstrated by the successful blockage of (13)C transport. Stem compression doubled stem respiration above treatment, reduced soil CO2 efflux by 34% and reduced phloem sucrose content by 50% compared with control trees. Stem respiration and soil CO2 efflux returned to normal within 3 weeks after pressure release, and (13)C labelling revealed recovery of phloem function the following year. Thus, we show that belowground phloem C transport can be reduced by compression, and we also demonstrate that trees recover after treatment, resuming C transport in the phloem. PMID:26377876

  3. Mixed metal dielectric pulse compression gratings

    NASA Astrophysics Data System (ADS)

    Néauport, J.; Bonod, N.; Hocquet, S.; Palmier, S.; Lavastre, E.; Baclet, N.; Dupuy, G.

    2010-11-01

    A Petawatt facility called PETAL (PETawatt Aquitaine Laser) is under development near the LIL (Ligne d'Integration Laser) at CEA Cesta, France. PETAL facility uses chirped pulse amplification (CPA) technique. This system needs large pulse compression grating exhibiting damage threshold of more than 4 J/cm2 normal beam at 1.053?m and for 500fs pulses. In this paper, we study an alternative design to the classic multilayer dielectric (MLD) grating called "mixed metal-multilayer dielectric grating" (MMLD). This design consists in a gold reflective layer coated with a few pairs of HfO2/SiO2. The top low index SiO2 layer of the stack is then engraved to receive the grating. We evidenced in a previous work that leads to high efficient pulse compression gratings. We have shown in last Boulder Damage Symposium that mixed mirror is equivalent to a "classic" MLD mirror. We herein detail the damage performances obtained on the MMLD gratings and compare them with these of MLD gratings.

  4. Laser-Driven Magnetic Field Compression

    NASA Astrophysics Data System (ADS)

    Jang, N.

    2005-10-01

    An experiment was designed to compress magnetic fields to ultrahigh intensities through laser-driven implosions. A seed axial magnetic field is produced through two Helmholtz coils using a capacitor charged by the hot electrons produced by an intense laser pulse as a power supply. The seed-field generation circuit is designed to produce an initial field of several Tesla (5--10 T) inside a cylindrical CH shell. The plastic shell is then imploded by direct laser irradiation with a 23-kJ laser pulse. Two implosion pulse shapes have been considered: a square pulse and a shaped, low-adiabat pulse. One-dimensional simulations of the magnetic field compression resulting from the shell convergence show magnetic field amplifications of 300 for the square pulse and 1000 for the shaped pulse, thus leading to peak magnetic fields of 3 x 10^3 T and 10^4 T, respectively (for a 10-T seed). Details of the experimental design and simulations are presented, and the experimental plans for implementation are outlined. This experiment is intended to study ways to improve the hot-spot energy confinement through magnetic insulation. This work has been supported by the US-DOE under grant ER54768 and under cooperative agreement DE-FC52-92SF19460.

  5. Self-calibration and biconvex compressive sensing

    NASA Astrophysics Data System (ADS)

    Ling, Shuyang; Strohmer, Thomas

    2015-11-01

    The design of high-precision sensing devises becomes ever more difficult and expensive. At the same time, the need for precise calibration of these devices (ranging from tiny sensors to space telescopes) manifests itself as a major roadblock in many scientific and technological endeavors. To achieve optimal performance of advanced high-performance sensors one must carefully calibrate them, which is often difficult or even impossible to do in practice. In this work we bring together three seemingly unrelated concepts, namely self-calibration, compressive sensing, and biconvex optimization. The idea behind self-calibration is to equip a hardware device with a smart algorithm that can compensate automatically for the lack of calibration. We show how several self-calibration problems can be treated efficiently within the framework of biconvex compressive sensing via a new method called SparseLift. More specifically, we consider a linear system of equations {\\boldsymbol{y}}={\\boldsymbol{D}}{\\boldsymbol{A}}{\\boldsymbol{x}}, where both {\\boldsymbol{x}} and the diagonal matrix {\\boldsymbol{D}} (which models the calibration error) are unknown. By ‘lifting’ this biconvex inverse problem we arrive at a convex optimization problem. By exploiting sparsity in the signal model, we derive explicit theoretical guarantees under which both {\\boldsymbol{x}} and {\\boldsymbol{D}} can be recovered exactly, robustly, and numerically efficiently via linear programming. Applications in array calibration and wireless communications are discussed and numerical simulations are presented, confirming and complementing our theoretical analysis.

  6. Frequency extrapolation by nonconvex compressive sensing

    SciTech Connect

    Chartrand, Rick; Sidky, Emil Y; Pan, Xiaochaun

    2010-12-03

    Tomographic imaging modalities sample subjects with a discrete, finite set of measurements, while the underlying object function is continuous. Because of this, inversion of the imaging model, even under ideal conditions, necessarily entails approximation. The error incurred by this approximation can be important when there is rapid variation in the object function or when the objects of interest are small. In this work, we investigate this issue with the Fourier transform (FT), which can be taken as the imaging model for magnetic resonance imaging (MRl) or some forms of wave imaging. Compressive sensing has been successful for inverting this data model when only a sparse set of samples are available. We apply the compressive sensing principle to a somewhat related problem of frequency extrapolation, where the object function is represented by a super-resolution grid with many more pixels than FT measurements. The image on the super-resolution grid is obtained through nonconvex minimization. The method fully utilizes the available FT samples, while controlling aliasing and ringing. The algorithm is demonstrated with continuous FT samples of the Shepp-Logan phantom with additional small, high-contrast objects.

  7. Compression socks and functional recovery following marathon running: a randomized controlled trial.

    PubMed

    Armstrong, Stuart A; Till, Eloise S; Maloney, Stephen R; Harris, Gregory A

    2015-02-01

    Compression socks have become a popular recovery aid for distance running athletes. Although some physiological markers have been shown to be influenced by wearing these garments, scant evidence exists on their effects on functional recovery. This research aims to shed light onto whether the wearing of compression socks for 48 hours after marathon running can improve functional recovery, as measured by a timed treadmill test to exhaustion 14 days following marathon running. Athletes (n = 33, age, 38.5 ± 7.2 years) participating in the 2012 Melbourne, 2013 Canberra, or 2013 Gold Coast marathons were recruited and randomized into the compression sock or placebo group. A graded treadmill test to exhaustion was performed 2 weeks before and 2 weeks after each marathon. Time to exhaustion, average and maximum heart rates were recorded. Participants were asked to wear their socks for 48 hours immediately after completion of the marathon. The change in treadmill times (seconds) was recorded for each participant. Thirty-three participants completed the treadmill protocols. In the compression group, average treadmill run to exhaustion time 2 weeks after the marathon increased by 2.6% (52 ± 103 seconds). In the placebo group, run to exhaustion time decreased by 3.4% (-62 ± 130 seconds), P = 0.009. This shows a significant beneficial effect of compression socks on recovery compared with placebo. The wearing of below-knee compression socks for 48 hours after marathon running has been shown to improve functional recovery as measured by a graduated treadmill test to exhaustion 2 weeks after the event. PMID:25627452

  8. COMPRESSION SOCKS AND FUNCTIONAL RECOVERY FOLLOWING MARATHON RUNNING: A RANDOMISED CONTROLLED TRIAL.

    PubMed

    Armstrong, Stuart A; Till, Eloise S; Maloney, Stephen; Harris, Gregory

    2014-09-01

    Compression socks have become a popular recovery aid for distance running athletes. Although some physiological markers have been shown to be influenced by wearing these garments, scant evidence exists on their effects on functional recovery. This research aims to shed light onto whether the wearing of compression socks for 48 hours after marathon running can improve functional recovery, as measured by a timed treadmill test to exhaustion 14 days following marathon running.Athletes (n=33, age = 38.5 ±7.2yrs) participating in the 2012 Melbourne, 2013 Canberra or 2013 Gold Coast marathons were recruited and randomised into the compression sock or placebo group. A graded treadmill test to exhaustion was performed 2 weeks prior and 2 weeks following each marathon. Time to exhaustion, average and maximum heart rates were recorded. Participants were asked to wear their socks for 48 hours immediately after completion of the marathon. The change in treadmill times (seconds) was recorded for each participant.33 participants completed the treadmill protocols. In the compression group average treadmill run to exhaustion time 2 weeks following the marathon increased by 2.6% (52s ±103s). In the placebo group run to exhaustion time decreased by 3.4% (-62s ±130s). P=0.009. This shows a significant beneficial effect of compression socks on recovery compared to placebo.The wearing of below knee compression socks for 48 hours after marathon running has been shown to improve functional recovery as measured by a graduated treadmill test to exhaustion 2 weeks following the event. PMID:25187242

  9. Cluster compression algorithm: A joint clustering/data compression concept

    NASA Technical Reports Server (NTRS)

    Hilbert, E. E.

    1977-01-01

    The Cluster Compression Algorithm (CCA), which was developed to reduce costs associated with transmitting, storing, distributing, and interpreting LANDSAT multispectral image data is described. The CCA is a preprocessing algorithm that uses feature extraction and data compression to more efficiently represent the information in the image data. The format of the preprocessed data enables simply a look-up table decoding and direct use of the extracted features to reduce user computation for either image reconstruction, or computer interpretation of the image data. Basically, the CCA uses spatially local clustering to extract features from the image data to describe spectral characteristics of the data set. In addition, the features may be used to form a sequence of scalar numbers that define each picture element in terms of the cluster features. This sequence, called the feature map, is then efficiently represented by using source encoding concepts. Various forms of the CCA are defined and experimental results are presented to show trade-offs and characteristics of the various implementations. Examples are provided that demonstrate the application of the cluster compression concept to multi-spectral images from LANDSAT and other sources.

  10. 2012 ARPA-E Energy Innovation Summit: Profiling General Compression: A River of Wind

    ScienceCinema

    Marcus, David; Ingersoll, Eric

    2012-03-21

    The third annual ARPA-E Energy Innovation Summit was held in Washington D.C. in February, 2012. The event brought together key players from across the energy ecosystem - researchers, entrepreneurs, investors, corporate executives, and government officials - to share ideas for developing and deploying the next generation of energy technologies. A few videos were selected for showing during the Summit to attendees. These 'performer videos' highlight innovative research that is ongoing and related to the main topics of the Summit's sessions. Featured in this video are David Marcus, Founder of General Compression, and Eric Ingersoll, CEO of General Compression. General Compression, with the help of ARPA-E funding, has created an advanced air compression process which can store and release more than a weeks worth of the energy generated by wind turbines.

  11. 2012 ARPA-E Energy Innovation Summit: Profiling General Compression: A River of Wind

    SciTech Connect

    Marcus, David; Ingersoll, Eric

    2012-02-29

    The third annual ARPA-E Energy Innovation Summit was held in Washington D.C. in February, 2012. The event brought together key players from across the energy ecosystem - researchers, entrepreneurs, investors, corporate executives, and government officials - to share ideas for developing and deploying the next generation of energy technologies. A few videos were selected for showing during the Summit to attendees. These 'performer videos' highlight innovative research that is ongoing and related to the main topics of the Summit's sessions. Featured in this video are David Marcus, Founder of General Compression, and Eric Ingersoll, CEO of General Compression. General Compression, with the help of ARPA-E funding, has created an advanced air compression process which can store and release more than a weeks worth of the energy generated by wind turbines.

  12. Compressible Turbulent Channel Flows: DNS Results and Modeling

    NASA Technical Reports Server (NTRS)

    Huang, P. G.; Coleman, G. N.; Bradshaw, P.; Rai, Man Mohan (Technical Monitor)

    1994-01-01

    The present paper addresses some topical issues in modeling compressible turbulent shear flows. The work is based on direct numerical simulation of two supersonic fully developed channel flows between very cold isothermal walls. Detailed decomposition and analysis of terms appearing in the momentum and energy equations are presented. The simulation results are used to provide insights into differences between conventional time-and Favre-averaging of the mean-flow and turbulent quantities. Study of the turbulence energy budget for the two cases shows that the compressibility effects due to turbulent density and pressure fluctuations are insignificant. In particular, the dilatational dissipation and the mean product of the pressure and dilatation fluctuations are very small, contrary to the results of simulations for sheared homogeneous compressible turbulence and to recent proposals for models for general compressible turbulent flows. This provides a possible explanation of why the Van Driest density-weighted transformation is so successful in correlating compressible boundary layer data. Finally, it is found that the DNS data do not support the strong Reynolds analogy. A more general representation of the analogy is analysed and shown to match the DNS data very well.

  13. Near-wall modelling of compressible turbulent flows

    NASA Technical Reports Server (NTRS)

    So, Ronald M. C.

    1990-01-01

    Work was carried out to formulate near-wall models for the equations governing the transport of the temperature-variance and its dissipation rate. With these equations properly modeled, a foundation is laid for their extension together with the heat-flux equations to compressible flows. This extension is carried out in a manner similar to that used to extend the incompressible near-wall Reynolds-stress models to compressible flows. The methodology used to accomplish the extension of the near-wall Reynolds-stress models is examined and the actual extension of the models for the Reynolds-stress equations and the near-wall dissipation-rate equation to compressible flows is given. Then the formulation of the near-wall models for the equations governing the transport of the temperature variance and its dissipation rate is discussed. Finally, a sample calculation of a flat plate compressible turbulent boundary-layer flow with adiabatic wall boundary condition and a free-stream Mach number of 2.5 using a two-equation near-wall closure is presented. The results show that the near-wall two-equation closure formulated for compressible flows is quite valid and the calculated properties are in good agreement with measurements. Furthermore, the near-wall behavior of the turbulence statistics and structure parameters is consistent with that found in incompressible flows.

  14. Near-wall modelling of compressible turbulent flows

    NASA Technical Reports Server (NTRS)

    So, Ronald M. C.

    1990-01-01

    Work was carried out to extend the near-wall models formulated for the incompressible Reynolds stress equations to compressible flows. The idea of splitting the compressible dissipation function into a solenoidal part that is not sensitive to changes of compressibility indicators and a compressible part that is directly affected by these changes is adopted. This means that all models involving the dissipation rate could be expressed in terms of the solenoidal dissipation rate and an equation governing its transport could be formulated to close the set of compressible Reynolds stress equations. The near-wall modelling of the dissipation rate equation is investigated and its behavior near a wall is studied in detail using k-epsilon closure. It is found that all existing modelled equations give the wrong behavior for the dissipation rate near a wall. Improvements are suggested and the resultant behavior is found to be in good agreement with near-wall data. Furthermore, the present modified k-epsilon closure is used too calculate a flat plate boundary layer and the results are compared with four existing k-epsilon closures. These comparisons show that all closures tested give essentially the same flow properties, except in a region very close to the wall. In this region, the present k-epsilon closure calculations are in better agreement with measurements and direct simulation data; in particular, the behavior of the dissipation rate.

  15. Isentropic Compression of Multicomponent Mixtures of Fuels and Inert Gases

    NASA Technical Reports Server (NTRS)

    Barragan, Michelle; Julien, Howard L.; Woods, Stephen S.; Wilson, D. Bruce; Saulsberry, Regor L.

    2000-01-01

    In selected aerospace applications of the fuels hydrazine and monomethythydrazine, there occur conditions which can result in the isentropic compression of a multicomponent mixture of fuel and inert gas. One such example is when a driver gas such as helium comes out of solution and mixes with the fuel vapor, which is being compressed. A second example is when product gas from an energetic device mixes with the fuel vapor which is being compressed. Thermodynamic analysis has shown that under isentropic compression, the fuels hydrazine and monomethylhydrazine must be treated as real fluids using appropriate equations of state. The appropriate equations of state are the Peng-Robinson equation of state for hydrazine and the Redlich-Kwong-Soave equation of state for monomethylhydrazine. The addition of an inert gas of variable quantity and input temperature and pressure to the fuel compounds the problem for safety design or analysis. This work provides the appropriate thermodynamic analysis of isentropic compression of the two examples cited. In addition to an entropy balance describing the change of state, an enthalpy balance is required. The presence of multicomponents in the system requires that appropriate mixing rules are identified and applied to the analysis. This analysis is not currently available.

  16. Space-frequency quantization for image compression with directionlets.

    PubMed

    Velisavljevi?, Vladan; Beferull-Lozano, Baltasar; Vetterli, Martin

    2007-07-01

    The standard separable 2-D wavelet transform (WT) has recently achieved a great success in image processing because it provides a sparse representation of smooth images. However, it fails to efficiently capture 1-D discontinuities, like edges or contours. These features, being elongated and characterized by geometrical regularity along different directions, intersect and generate many large magnitude wavelet coefficients. Since contours are very important elements in the visual perception of images, to provide a good visual quality of compressed images, it is fundamental to preserve good reconstruction of these directional features. In our previous work, we proposed a construction of critically sampled perfect reconstruction transforms with directional vanishing moments imposed in the corresponding basis functions along different directions, called directionlets. In this paper, we show how to design and implement a novel efficient space-frequency quantization (SFQ) compression algorithm using directionlets. Our new compression method outperforms the standard SFQ in a rate-distortion sense, both in terms of mean-square error and visual quality, especially in the low-rate compression regime. We also show that our compression method, does not increase the order of computational complexity as compared to the standard SFQ algorithm. PMID:17605375

  17. Compression of multispectral image using HEVC

    NASA Astrophysics Data System (ADS)

    Gao, Feiyu; Ji, Xiangyang; Yan, Chenggang; Dai, Qionghai

    2014-10-01

    Predictive Lossy Compression has been found to be an interesting alternative to conventional transform coding techniques in multispectral image compression. Recently, High Efficiency Video Coding (HEVC) standard has shown significant improvement over state of the art transformation based still-image coding standard. In this paper we study the properties of multispectral image and propose a predictive lossy compression scheme based on HEVC. Empirical analysis shows that our proposed method is superior to the existing state of the art predictive lossy compression schemes.

  18. 29 CFR 1926.803 - Compressed air.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Compressed air. 1926.803 Section 1926.803 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Underground Construction, Caissons, Cofferdams and Compressed Air § 1926.803 Compressed...

  19. Tomographic Image Compression Using Multidimensional Transforms.

    ERIC Educational Resources Information Center

    Villasenor, John D.

    1994-01-01

    Describes a method for compressing tomographic images obtained using Positron Emission Tomography (PET) and Magnetic Resonance (MR) by applying transform compression using all available dimensions. This takes maximum advantage of redundancy of the data, allowing significant increases in compression efficiency and performance. (13 references) (KRN)

  20. General-Purpose Compression for Efficient Retrieval.

    ERIC Educational Resources Information Center

    Cannane, Adam; Williams, Hugh E.

    2001-01-01

    Discusses compression of databases that reduces space requirements and retrieval times; considers compression of documents in text databases based on semistatic modeling with words; and proposes a scheme for general purpose compression that can be applied to all types of data stored in large collections. (Author/LRW)

  1. Multichannel Compression, Temporal Cues, and Audibility.

    ERIC Educational Resources Information Center

    Souza, Pamela E.; Turner, Christopher W.

    1998-01-01

    The effect of the reduction of the temporal envelope produced by multichannel compression on recognition was examined in 16 listeners with hearing loss, with particular focus on audibility of the speech signal. Multichannel compression improved speech recognition when superior audibility was provided by a two-channel compression system over linear…

  2. Activities across Nation Mark National Chemistry Week.

    ERIC Educational Resources Information Center

    Carpenter, Ernest, Ed.; And Others

    1989-01-01

    Describes national and local activities done during National Chemistry Week including chemistry demonstrations, shopping center exhibits, contests, and museum exhibits. Discusses the supplementary material about chemistry in selected editions of 16 newspapers, "Solution for the Future." Presents many pictures showing those activities. (YP)

  3. Science week: May 11”17

    NASA Astrophysics Data System (ADS)

    National Science Week, an event launched last year by the National Science Foundation (NSF), will be observed thi s year from May 11 to May 17, 1986. In support of this effort, NSF is urging individuals or organizations to sponsor science and math competitions or fairs, arrange "open house" events at research facilities, organize educational programs and scientific demonstrations, and arrange or participate in other activities. National Science Week is intended to increase public awareness and understanding of science and technology and to encourage young people in the United States to become more involved with and consider careers in science and mathematics. Educational packets will be made available to schools, public libraries, and science museums. The corporate sponsors of National Science Week are the Amoco Foundation, the Atlantic Richfield Foundation, the Dow Chemical Company Foundation, the DuPont Company, the Eastman Kodak Company, the General Electric Foundation, and IBM. For more information, write to National Science Week '86, c/o National Science Foundation, 1800 G Street, N.W., Washington, DC 20550 (telephone: 1-800-227-SEEK).

  4. 77 FR 62133 - Fire Prevention Week, 2012

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-12

    ... America the two hundred and thirty-seventh. (Presidential Sig.) [FR Doc. 2012-25228 Filed 10-11-12; 8:45... Documents#0;#0; #0; #0;Title 3-- #0;The President ] Proclamation 8881 of October 5, 2012 Fire Prevention Week, 2012 By the President of the United States of America A Proclamation Every year, fires in...

  5. 78 FR 62305 - Fire Prevention Week, 2013

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-16

    ...- eighth. (Presidential Sig.) [FR Doc. 2013-24498 Filed 10-15-13; 8:45 am] Billing code 3295-F4 ... Documents#0;#0; #0; #0;Title 3-- #0;The President ] Proclamation 9034 of October 4, 2013 Fire Prevention Week, 2013 By the President of the United States of America A Proclamation Fires take more...

  6. Telling the Public--It's Science Week

    ERIC Educational Resources Information Center

    Auty, Geoff

    2011-01-01

    This article describes an opportunity to engage the public in demonstrating and explaining some aspects of science. About 10 years ago, the author met Peter Evennett in the ASE Conference exhibition. Peter was a member of the Leeds Philosophical and Literary Society and currently its president. As a contribution to "Science Week" (which dates back…

  7. National Women's History Week Curriculum Guide.

    ERIC Educational Resources Information Center

    Women's Support Network, Inc., Santa Rosa, CA.

    Designed for elementary and secondary level use, the ideas, materials, and resources in this guide are intended to facilitate teachers' first efforts at expanding the study of women in U.S. history. The cross-cultural guide provides introductory information and suggestions to help develop classroom observances for the National Women's History Week…

  8. Sea/River Week Career Profiles.

    ERIC Educational Resources Information Center

    Alaska State Dept. of Education, Juneau. Div. of Adult and Vocational Education.

    The aim of these materials is to interest students in jobs related to Alaska's natural resources. They coordinate with the Sea Week curriculum and the Alaska vocational state model curriculum in renewable natural resources in agriculture. Each of the 2-page career profiles includes a brief description of a person's job along with that person's…

  9. The Four-Day School Week.

    ERIC Educational Resources Information Center

    Reeves, Kimberly

    1999-01-01

    In New Mexico, 18 out of 89 school districts are on the four-day school week. So are many rural Colorado, Oregon, and Colorado schools. Implemented as a fiscal last resort, this schedule has had unexpected educational benefits for districts. Attendance has improved and student achievement on standardized tests remains stable. (MLH)

  10. First Few Weeks on Campus. Prevention Update

    ERIC Educational Resources Information Center

    Higher Education Center for Alcohol, Drug Abuse, and Violence Prevention, 2010

    2010-01-01

    Every fall, college and university campuses and communities brace for the onslaught of new and returning students. For first-year students, anecdotal evidence suggests that the first six weeks of enrollment are critical to success. Because many students initiate heavy drinking during these early days of college, the potential exists for excessive…

  11. The Four-Day School Week. Revised.

    ERIC Educational Resources Information Center

    Colorado State Dept. of Education, Denver.

    This paper provides an overview of the 4-day school week being utilized by 36 school districts in Colorado. These districts, which tend to be rural and sparsely populated, schedule 7.5 hours per day for 144 days of school instead of the normal 6 hours for 180 days. Colorado law requires school districts to schedule 1,080 hours per year of…

  12. Report on the Survival Week Program 1974.

    ERIC Educational Resources Information Center

    Lopez, Homero

    The 1974 Survival Week Program was an orientation program designed for entering minority and economically disadvantaged students at the University of Texas at Austin. The major purpose of the program was to assist the participants in acquiring the knowledge and skills for academic, financial, emotional, and social "survival" in a complex…

  13. [Medical image compression: a review].

    PubMed

    Noreña, Tatiana; Romero, Eduardo

    2013-01-01

    Modern medicine is an increasingly complex activity , based on the evidence ; it consists of information from multiple sources : medical record text , sound recordings , images and videos generated by a large number of devices . Medical imaging is one of the most important sources of information since they offer comprehensive support of medical procedures for diagnosis and follow-up . However , the amount of information generated by image capturing gadgets quickly exceeds storage availability in radiology services , generating additional costs in devices with greater storage capacity . Besides , the current trend of developing applications in cloud computing has limitations, even though virtual storage is available from anywhere, connections are made through internet . In these scenarios the optimal use of information necessarily requires powerful compression algorithms adapted to medical activity needs . In this paper we present a review of compression techniques used for image storage , and a critical analysis of them from the point of view of their use in clinical settings. PMID:23715317

  14. Stability of compressible boundary layers

    NASA Technical Reports Server (NTRS)

    Nayfeh, Ali H.

    1989-01-01

    The stability of compressible 2-D and 3-D boundary layers is reviewed. The stability of 2-D compressible flows differs from that of incompressible flows in two important features: There is more than one mode of instability contributing to the growth of disturbances in supersonic laminar boundary layers and the most unstable first mode wave is 3-D. Whereas viscosity has a destabilizing effect on incompressible flows, it is stabilizing for high supersonic Mach numbers. Whereas cooling stabilizes first mode waves, it destabilizes second mode waves. However, second order waves can be stabilized by suction and favorable pressure gradients. The influence of the nonparallelism on the spatial growth rate of disturbances is evaluated. The growth rate depends on the flow variable as well as the distance from the body. Floquet theory is used to investigate the subharmonic secondary instability.

  15. Culture: copying, compression, and conventionality.

    PubMed

    Tamariz, Mónica; Kirby, Simon

    2015-01-01

    Through cultural transmission, repeated learning by new individuals transforms cultural information, which tends to become increasingly compressible (Kirby, Cornish, & Smith, ; Smith, Tamariz, & Kirby, ). Existing diffusion chain studies include in their design two processes that could be responsible for this tendency: learning (storing patterns in memory) and reproducing (producing the patterns again). This paper manipulates the presence of learning in a simple iterated drawing design experiment. We find that learning seems to be the causal factor behind the increase in compressibility observed in the transmitted information, while reproducing is a source of random heritable innovations. Only a theory invoking these two aspects of cultural learning will be able to explain human culture's fundamental balance between stability and innovation. PMID:25039798

  16. Effects of Progressive Resistance Training Integrated with Foot and Ankle Compression on Spatiotemporal Gait Parameters of Individuals with Stroke

    PubMed Central

    Lee, Na Kyung; Son, Sung Min; Nam, Seok Hyun; Kwon, Jung Won; Kang, Kyung Woo; Kim, Kyoung

    2013-01-01

    [Purpose] The purpose of this study was to investigate the effect of progressive resistance training (PRT) integrated with foot and ankle compression on the gait ability of post-stroke patients. [Subjects and Methods] Participants were randomly allocated to two groups: the PRT group (n=14) and the control group (n=14). Subjects in the PRT group received training for 30 minutes, five days per week, for a period of six weeks. Gait ability was evaluated using the RsScan system. [Results] Use of PRT integrated with foot and ankle compression resulted in significant improvements in temporal parameters (gait velocity, step time, and double limb support) and spatial parameters (step length, stride length, and heel-to- heel base of support). [Conclusion] Progressive resistance training integrated with foot and ankle compression improved the gait ability of stroke patients. These results suggest the feasibility and suitability of integration of PRT with foot and ankle compression for individuals with stroke. PMID:24259765

  17. Turbulence modeling for compressible flows

    NASA Technical Reports Server (NTRS)

    Marvin, J. G.

    1977-01-01

    Material prepared for a course on Applications and Fundamentals of Turbulence given at the University of Tennessee Space Institute, January 10 and 11, 1977, is presented. A complete concept of turbulence modeling is described, and examples of progess for its use in computational aerodynimics are given. Modeling concepts, experiments, and computations using the concepts are reviewed in a manner that provides an up-to-date statement on the status of this problem for compressible flows.

  18. Compressed air energy storage system

    SciTech Connect

    Ahrens, F.W.; Kartsounes, G.T.

    1981-07-28

    An internal combustion reciprocating engine is operable as a compressor during slack demand periods utilizing excess power from a power grid to charge air into an air storage reservoir and as an expander during peak demand periods to feed power into the power grid utilizing air obtained from the air storage reservoir together with combustible fuel. Preferably the internal combustion reciprocating engine is operated at high pressure and a low pressure turbine and compressor are also employed for air compression and power generation.

  19. Compressing TV-image data

    NASA Technical Reports Server (NTRS)

    Hilbert, E. E.; Lee, J.; Rice, R. F.; Schlutsmeyer, A. P.

    1981-01-01

    Compressing technique calculates activity estimator for each segment of image line. Estimator is used in conjunction with allowable bits per line, N, to determine number of bits necessary to code each segment and which segments can tolerate truncation. Preprocessed line data are then passed to adaptive variable-length coder, which selects optimum transmission code. Method increases capacity of broadcast and cable television transmissions and helps reduce size of storage medium for video and digital audio recordings.

  20. Compressed air energy storage system

    DOEpatents

    Ahrens, Frederick W. (Naperville, IL); Kartsounes, George T. (Naperville, IL)

    1981-01-01

    An internal combustion reciprocating engine is operable as a compressor during slack demand periods utilizing excess power from a power grid to charge air into an air storage reservoir and as an expander during peak demand periods to feed power into the power grid utilizing air obtained from the air storage reservoir together with combustible fuel. Preferably the internal combustion reciprocating engine is operated at high pressure and a low pressure turbine and compressor are also employed for air compression and power generation.

  1. 76 FR 4338 - Research and Development Strategies for Compressed & Cryo-Compressed Hydrogen Storage Workshops

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-25

    ... Research and Development Strategies for Compressed & Cryo- Compressed Hydrogen Storage Workshops AGENCY... Laboratory, in conjunction with the Hydrogen Storage team of the EERE Fuel Cell Technologies Program, will be hosting two days of workshops on compressed and cryo-compressed hydrogen storage in the Washington,...

  2. Modeling of compressible cake filtration

    SciTech Connect

    Abbound, N.M. . Dept. of Civil Engineering); Corapcioglu, M.Y. . Dept. of Civil Engineering)

    1993-10-15

    The transport of suspended solid particles in a liquid through porous media has importance from the viewpoint of engineering practice and industrial applications. Deposition of solid particles on a filter cloth or on a pervious porous medium forms the filter cakes. Following a literature survey, a governing equation for the cake thickness is obtained by considering an instantaneous material balance. In addition to the conservation of mass equations for the liquid, and for suspended and captured solid particles, functional relations among porosity, permeability, and pressure are obtained from literature and solved simultaneously. Later, numerical solutions for cake porosity, pore pressure, cake permeability, velocity of solid particles, concentration of suspended solid particles, and net rate of deposition are obtained. At each instant of time, the porosity decreases throughout the cake from the surface to the filter septum where it has the smallest value. As the cake thickness increases, the trends in pressure variation are similar to data obtained by other researchers. This comparison shows the validity of the theory and the associated solution presented. A sensitivity analysis shows higher pressure values at the filter septum for a less pervious membrane. Finally, a reduction in compressibility parameter provides a thicker cake, causes more particles to be captured inside the cake, and reduces the volumetric filtrate rate. The increase of solid velocity with the reduction in compressibility parameter shows that more rigid cakes compress less.

  3. On Wavelet Matrix Compression for Differential Equations

    NASA Astrophysics Data System (ADS)

    ?erná, Dana; Fin?k, Václav

    2011-09-01

    The design of most adaptive wavelet methods for solving differential equations follows a general concept proposed by A. Cohen, W. Dahmen and R. DeVore in [5, 6]. The essential steps are: transformation of the variational formulation into the well-conditioned infinite-dimensional l2 problem, finding of the convergent iteration process for the l2 problem and finally derivation of its finite dimensional version which works with an inexact right hand side and approximate matrix-vector multiplication. In our contribution, we shortly review all these parts with emphasis on the approximate matrix-vector multiplication. Efficient approximation of matrix-vector multiplication is enabled by an off-diagonal decay of entries of the wavelet stiffness matrix and by decay of entries of load vector in wavelet coordinates. Besides an usual truncation in scale, we apply here also a truncation in space to compress wavelet stiffness matrices efficiently. At the end, we show some numerical experiments.

  4. A compressed sensing perspective of hippocampal function

    PubMed Central

    Petrantonakis, Panagiotis C.; Poirazi, Panayiota

    2014-01-01

    Hippocampus is one of the most important information processing units in the brain. Input from the cortex passes through convergent axon pathways to the downstream hippocampal subregions and, after being appropriately processed, is fanned out back to the cortex. Here, we review evidence of the hypothesis that information flow and processing in the hippocampus complies with the principles of Compressed Sensing (CS). The CS theory comprises a mathematical framework that describes how and under which conditions, restricted sampling of information (data set) can lead to condensed, yet concise, forms of the initial, subsampled information entity (i.e., of the original data set). In this work, hippocampus related regions and their respective circuitry are presented as a CS-based system whose different components collaborate to realize efficient memory encoding and decoding processes. This proposition introduces a unifying mathematical framework for hippocampal function and opens new avenues for exploring coding and decoding strategies in the brain. PMID:25152718

  5. Compressibility effects in shaped charge jet penetration

    NASA Astrophysics Data System (ADS)

    Haugstad, B. S.

    1981-03-01

    Among other hypotheses, the classical theory of high-speed penetration assumes the incompressibility of both the projectile and target. Employing a simple Murnaghan equation of state, we show here that direct compressibility effects (pv-work) on penetration depth are at most on the order of 10-15% for projectile speeds as high as 104 ms-1. Our results agree closely with similar results by Coombs (private communication, Royal Air Force Research Establishment, 1978), who used a more complex five-parameter equation of state. This indicates that rather simple equations of state may adequately represent essential thermodynamic features of high-speed penetration phenomena. The equation of state employed here furthermore allows approximate analytical results to be derived for both small and large projectile velocities.

  6. Local density dependent potential for compressible mesoparticles.

    PubMed

    Faure, Gérôme; Maillet, Jean-Bernard; Stoltz, Gabriel

    2014-03-21

    This work proposes a coarse grained description of molecular systems based on mesoparticles representing several molecules, where interactions between mesoparticles are modelled by an interparticle potential of molecular type. Since strong non-equilibrium situations over a wide range of pressure and density are targeted, the internal compressibility of the mesoparticles has to be considered. This is done by introducing a dependence of the potential on the local environment of the mesoparticles. To define local densities, we resort to a three-dimensional Voronoi tessellation instead of standard local, spherical averages. As an example, a local density dependent potential is fitted to reproduce the Hugoniot curve of a model of nitromethane over a large range of pressures and densities. PMID:24655170

  7. Compression failure of angle-ply laminates

    NASA Technical Reports Server (NTRS)

    Peel, L. D.; Hyer, M. W.; Shuart, M. J.

    1992-01-01

    Test results from the compression loading of (+ or - Theta/ - or + Theta)(sub 6s) angle-ply IM7-8551-7a specimens, 0 less than or = Theta less than or = 90 degs, are presented. The observed failure strengths and modes are discussed, and typical stress-strain relations shown. Using classical lamination theory and the maximum stress criterion, an attempt is made to predict failure stress as a function of Theta. This attempt results in poor correlation with test results and thus a more advanced model is used. The model, which is based on a geometrically nonlinear theory, and which was taken from previous work, includes the influence of observed layer waviness. The waviness is described by the wave length and the wave amplitude. The theory is briefly described and results from the theory are correlated with test results. It is shown that by using levels of waviness observed in the specimens, the correlation between predictions and observations is good.

  8. Quantum Bootstrapping via Compressed Quantum Hamiltonian Learning

    NASA Astrophysics Data System (ADS)

    Wiebe, Nathan; Granade, Christopher; Cory, David

    2015-03-01

    Recent work has shown that quantum simulation is a valuable tool for learning empirical models for quantum systems. We build upon these results by showing that a small quantum simulators can be used to characterize and learn control models for larger devices for wide classes of physically realistic Hamiltonians. This leads to a new application for small quantum computers: characterizing and controlling larger quantum computers. Our protocol achieves this by using Bayesian inference in concert with Lieb-Robinson bounds and interactive quantum learning methods to achieve compressed simulations for characterization. Whereas Fisher information analysis shows that current methods which employ short-time evolution are suboptimal, interactive quantum learning allows us to overcome this limitation. We illustrate the efficiency of our bootstrapping protocol by showing numerically that an 8-qubit Ising model simulator can be used to calibrate and control a 50 qubit Ising simulator while using only about 750 kilobits of experimental data.

  9. Finite scale equations for compressible fluid flow

    SciTech Connect

    Margolin, Len G

    2008-01-01

    Finite-scale equations (FSE) describe the evolution of finite volumes of fluid over time. We discuss the FSE for a one-dimensional compressible fluid, whose every point is governed by the Navier-Stokes equations. The FSE contain new momentum and internal energy transport terms. These are similar to terms added in numerical simulation for high-speed flows (e.g. artificial viscosity) and for turbulent flows (e.g. subgrid scale models). These similarities suggest that the FSE may provide new insight as a basis for computational fluid dynamics. Our analysis of the FS continuity equation leads to a physical interpretation of the new transport terms, and indicates the need to carefully distinguish between volume-averaged and mass-averaged velocities in numerical simulation. We make preliminary connections to the other recent work reformulating Navier-Stokes equations.

  10. 3 CFR 8906 - Proclamation 8906 of November 16, 2012. National Family Week, 2012

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Administration has also pursued greater workplace flexibility, so working parents do not face a choice between... economic recovery continues, we must keep working to give them the security they deserve, and to widen the circle of opportunity for all who are working hard to get ahead. During National Family Week, let...

  11. Does Shortening the School Week Impact Student Performance? Evidence from the Four-Day School Week

    ERIC Educational Resources Information Center

    Anderson, D. Mark; Walker, Mary Beth

    2015-01-01

    School districts use a variety of policies to close budget gaps and stave off teacher layoffs and furloughs. More schools are implementing four-day school weeks to reduce overhead and transportation costs. The four-day week requires substantial schedule changes as schools must increase the length of their school day to meet minimum instructional…

  12. PERSISTENT EFFECTS OF REPEATED INHALATION OF TOLUENE: 4 WEEKS VS. 13 WEEKS.

    EPA Science Inventory

    Understanding and predicting the extent of neurotoxic damage from repeated exposure to volatile organic compounds (VOCs) is a problem for many EPA programs. Eighty adult, male Long-Evans rats inhaled toluene (0, 10, 100, or 1000 ppm) 6 hr/day, 5 days/week for 4 weeks in a systema...

  13. Does Shortening the School Week Impact Student Performance? Evidence from the Four-Day School Week

    ERIC Educational Resources Information Center

    Anderson, D. Mark; Walker, Mary Beth

    2015-01-01

    School districts use a variety of policies to close budget gaps and stave off teacher layoffs and furloughs. More schools are implementing four-day school weeks to reduce overhead and transportation costs. The four-day week requires substantial schedule changes as schools must increase the length of their school day to meet minimum instructional…

  14. Knee Extension Range of Motion at 4 Weeks Is Related to Knee Extension Loss at 12 Weeks After Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Noll, Sarah; Garrison, J. Craig; Bothwell, James; Conway, John E.

    2015-01-01

    Background: The anterior cruciate ligament (ACL) is commonly torn, and surgical reconstruction is often required to allow a patient to return to their prior level of activity. Avoiding range of motion (ROM) loss is a common goal, but little research has been done to identify when ROM loss becomes detrimental to a patient’s future function. Purpose: To determine whether there is a relationship between early knee side-to-side extension difference after ACL reconstruction and knee side-to-side extension difference at 12 weeks. The hypothesis was that early (within the first 8 weeks) knee side-to-side extension difference will be predictive of knee side-to-side extension difference seen at 12 weeks. Study Design: Cohort study; Level of evidence, 3. Methods: Knee side-to-side extension difference measures were taken on 74 patients undergoing ACL reconstruction rehabilitation at the initial visit and 4, 8, and 12 weeks postoperatively. Visual analog scores (VAS) and International Knee Documentation Committee (IKDC) scores were also recorded at these time frames. Results: There was a strong relationship between knee extension ROM at 4 and 12 weeks (r = 0.639, P < .001) and 8 and 12 weeks (r = 0.742, P < .001). When the variables of knee extension ROM at initial visit and 4 and 8 weeks were entered into a regression analysis, the predictor variable explained 61% (R2 = 0.611) of variance for knee extension ROM at 12 weeks, with 4 weeks (R2 = 0.259) explaining the majority of this variance. Conclusion: This study found that a patient’s knee extension at 4 weeks was strongly correlated with knee extension at 12 weeks. Clinical Relevance: This information may be useful for clinicians treating athletic patients who are anxious for return to sport by providing them an initial goal to work toward in hopes of ensuring successful rehabilitation of their knee. PMID:26675061

  15. Changing the Way We Work

    ERIC Educational Resources Information Center

    Coote, Anna

    2010-01-01

    A 21-hour working week is a long way from today's standard of 40 hours or more, but not so far-fetched when people consider the infinitely varied ways in which they actually spend their time. On average, people of working age spend 19.6 hours a week in paid employment and 20.4 hours in unpaid housework and childcare. These averages mask huge…

  16. Changing the Way We Work

    ERIC Educational Resources Information Center

    Coote, Anna

    2010-01-01

    A 21-hour working week is a long way from today's standard of 40 hours or more, but not so far-fetched when people consider the infinitely varied ways in which they actually spend their time. On average, people of working age spend 19.6 hours a week in paid employment and 20.4 hours in unpaid housework and childcare. These averages mask huge…

  17. Oral 4-week and 13-week toxicity studies of polyvinyl acetate vinyl laurate copolymer in rats.

    PubMed

    Messinger, Horst; Bär, Albert

    2014-10-01

    Polyvinyl acetate vinyl laurate copolymer (PVAcVL) is a useful component of gum base for chewing gum production. The safety of PVAcVL was examined in a 4-week and a 13-week oral toxicity study in rats. Finely powdered PVAcVL was administered with the diet at levels of 1.25%, 2.0% and 5% in the 4-week study and 1.25%, 2.5% and 5% in the 13-week study. There were no treatment related effects on mortality, bodyweight gains feed efficiency, ophthalmoscopic findings, hematological and clinical chemical parameters, neurobehavioral observations as well as gross and histopathological changes of standard organs and tissues. The highest dose tested in the 13-week study (3783 and 4396mg/kgbw/d for males and females, respectively) proved to be a NOAEL. PMID:24932800

  18. Weekly petroleum status report. Data for week ended, October 21, 1994

    SciTech Connect

    Not Available

    1994-11-01

    The Weekly Petroleum Status Report (WPSR) provides timely information on the petroleum supply situation in the context of historical information, selected prices, and forecasts. The WPSR is intended to provide up-to-date information to the industry, the press, planners, policymakers, consumers, analysts, and State and local governments. It is published each Thursday by the Energy Information Administration (EIA) and excerpts of the data are available electronically after 9:00 a.m. Wednesday. The data contained in this report are based on company submissions for the week ending 7:00 a.m. the preceding Friday. For some weeks which include holidays, publication of the WPSR is delayed by 1 day. The WPSR is not published during 1 of the last 2 weeks of the year depending upon which day of the week Christmas occurs.

  19. Mechanical properties of human enamel under compression: On the feature of calculations.

    PubMed

    Zaytsev, Dmitry

    2016-05-01

    The paper is aimed at determination of the causes of shape effect in human tooth enamel under compression and correction of the relevant mechanical characteristics. For this purpose, six groups of samples with different ratios of the compression surface diagonal to the sample height, which consisted of 10 cuboid samples in each, were prepared from the backside of human enamel. The lateral deformation of a sample was calculated at the maximum compressive stress for correction of the mechanical characteristics. It is shown that the ratio between the lateral and axial deformations decreases with an increase in the ratio of the compression surface diagonal to the sample height. This is caused by the friction between the compression plates and the working surfaces of the enamel sample when the lateral deformation is suppressed. In addition, the slope of enamel sample by about 15° occurred during compression due to the inclination of rigid and low deformable enamel rods. The corrections of the elastic modulus and the compression strength taking into account the lateral deformation and the sample slope are carried out. The mechanical properties of enamel samples with the 2.1 aspect ratio are closer to the intrinsic properties of human enamel samples. The elastic modulus and the compression strength of human enamel under compression are 5.64GPa and 363MPa, respectively. The lateral deformation (~10%) may be considered as the critical parameter that indicates the strength of human enamel. PMID:26952454

  20. Euclid: image compression activities for the VIS instrument

    NASA Astrophysics Data System (ADS)

    Giusi, Giovanni; Liu, Scige J.; Li Causi, Gianluca; Niemi, Sami M.; Di Giorgio, Anna Maria; Galli, Emanuele; Farina, Maria

    2014-08-01

    Euclid is a space mission dedicated to the high-precision study of dark energy and dark matter. Its visible instrument (VIS) will acquire wide field images by means of an array of 36 CCD focal plane detectors. Considering that each acquired full frame produces a huge amount of data (~1.2GByte), an overall daily production of ~120 GByte is expected, which must be compressed to fit the 520 Gbit VIS daily telemetry. Due to the highly demanding science requirements such compression must be rigorously lossless. This software requirement is very hard to meet because of the following constraints: i) the average Compression Ratio (CR) must be greater than 2.8; ii) the activities of data compression inside the Control Data Processing Unit and transmission towards the satellite shall complete in less than 369s, that fits to the acquisition time of the near-infrared instrument; and iii) the compressors parameters as well as the transmission packet size must be tuned to ensure minimal data loss in case of transmission errors. The results obtained with 1D and 2D compression algorithms based on the CCSDS 121 and CCSDS 122 recommended standards, fed with improved focal plane simulations, have been compared to each other. Moreover, a set of various reordering and pre-processing procedures has been applied to the read-out data stream, considering different sizes of the input data segments. The overall scope of these comparative works has been not only to maximize the compression ratio and to minimize the compression time, but also to provide a trade-off between the input data size and the minimum output compressed data segment in order to minimize the data loss due to transmission errors propagation. From our test we found that performing a full (at CCD level) reordering of the read-out data-stream leads to a better compression ratio with both algorithms. The CCSDS 121, however, gives the best results in terms of CR. Finally we found that, for the considered simulated images, the standard pre-processing activities like bias subtraction, bitshift and windowing do not affect the CR significantly. Analogously an additional analysis of the effect of the expected source crowding showed that it is also not important.