Letteratura scientifica selezionata sul tema "Timing Irregularity"
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Articoli di riviste sul tema "Timing Irregularity"
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Tahara, Yu, Saneyuki Makino, Takahiko Suiko, Yuki Nagamori, Takao Iwai, Megumi Aono e Shigenobu Shibata. "Association between Irregular Meal Timing and the Mental Health of Japanese Workers". Nutrients 13, n. 8 (13 agosto 2021): 2775. http://dx.doi.org/10.3390/nu13082775.
Testo completoAbstract (sommario):
Breakfast skipping and nighttime snacking have been identified as risk factors for obesity, diabetes, and cardiovascular diseases. However, the effects of irregularity of meal timing on health and daily quality of life are still unclear. In this study, a web-based self-administered questionnaire survey was conducted involving 4490 workers (73.3% males; average age = 47.4 ± 0.1 years) in Japan to investigate the association between meal habits, health, and social relationships. This study identified that irregular meal timing was correlated with higher neuroticism (one of the Big Five personality traits), lower physical activity levels, and higher productivity loss. Irregular meal timing was also associated with a higher incidence of sleep problems and lower subjective health conditions. Among health outcomes, a high correlation of irregular meal timing with mental health factors was observed. This study showed that irregularity of meal timing can be explained by unbalanced diets, frequent breakfast skipping, increased snacking frequency, and insufficient latency from the last meal to sleep onset. Finally, logistic regression analysis was conducted, and a significant contribution of meal timing irregularity to subjective mental health was found under adjustment for other confounding factors. These results suggest that irregular meal timing is a good marker of subjective mental health issues.
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Hoopes, Elissa, Michele D'Agata, Talia Brookstein-Burke, Shannon Robson, Melissa Witman, Susan Malone e Freda Patterson. "0003 On the Same Wavelength? Quantifying the Associations between Eating Timing and Rest-Activity Rhythms in Free-Living Adults". Sleep 45, Supplement_1 (25 maggio 2022): A1—A2. http://dx.doi.org/10.1093/sleep/zsac079.002.
Testo completoAbstract (sommario):
Abstract Introduction Misalignment between the central circadian clock and daily behaviors increases cardiometabolic morbidity and mortality risk, likely due to internal misalignment between central and peripheral circadian rhythms. Experimental studies suggest food intake may act as a time cue (‘zeitgeber’) for resetting circadian rhythms, representing a potential behavioral target to ameliorate circadian misalignment and associated health consequences. However, the extent to which eating timing relates to circadian rhythms in free-living adults is unclear. Therefore, we tested the associations between eating timing with 24-h rest-activity-rhythms (RAR), a free-living proxy for endogenous circadian rhythms, in non-shift-working adults. Methods Adults without chronic health conditions or sleep disorders completed 14 days of 24/7 wrist accelerometry to evaluate RAR variables of interdaily stability (IS; day-to-day stability in RAR), intradaily variability (IV; within-day fragmentation of RAR), relative amplitude (RA; difference between peak vs. trough activity), L5 onset time (5-h period with lowest activity), and M10 onset time (10-h period with highest activity). Concurrently, time-stamped image-assisted diet records were obtained to generate average eating timing variables, including daily eating onset (time of first caloric intake after awakening), offset (last caloric intake time), duration (time elapsed between eating onset and offset), and caloric midpoint (time at which 50% of daily kcals were consumed), and variables illustrating irregularity in eating timing (standard deviation of eating timing variables). Pearson’s correlations quantified the associations between RAR and eating timing variables. Results Participants (N=30) were 28.0±6.6 years, 57% female, with a BMI of 23.8±2.5 kg/m2. Higher IS was correlated with lower irregularity in both eating onset (r=-0.55, p<0.01) and duration (r=-0.51, p<0.01). Higher RA correlated with earlier eating onset (r=-0.47, p<0.01), longer eating duration (r=0.53, p<0.01), and lower eating onset irregularity (r=-0.37, p<0.05). Later L5 correlated with later eating onset (r=0.67, p<0.001), offset (r=0.58, p<0.001), caloric midpoint (r=0.56, p<0.01), and greater eating offset irregularity (r=0.53, p<0.01). Later M10 correlated with later eating offset (r=0.40, p<0.05). Conclusion Preliminary findings indicate that eating timing and RAR are moderately correlated in free-living adults. Earlier eating timing, increased eating regularity, and longer daily eating duration may represent behavioral targets for improving circadian rhythms and subsequent cardiometabolic outcomes. Support (If Any): Support provided by the American Heart Association (#831488) and a University of Delaware Research Fund-Strategic Initiative Award.
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Christodoulou, Chris, e Aristodemos Cleanthous. "Does High Firing Irregularity Enhance Learning?" Neural Computation 23, n. 3 (marzo 2011): 656–63. http://dx.doi.org/10.1162/neco_a_00090.
Testo completoAbstract (sommario):
In this note, we demonstrate that the high firing irregularity produced by the leaky integrate-and-fire neuron with the partial somatic reset mechanism, which has been shown to be the most likely candidate to reflect the mechanism used in the brain for reproducing the highly irregular cortical neuron firing at high rates (Bugmann, Christodoulou, & Taylor, 1997 ; Christodoulou & Bugmann, 2001 ), enhances learning. More specifically, it enhances reward-modulated spike-timing-dependent plasticity with eligibility trace when used in spiking neural networks, as shown by the results when tested in the simple benchmark problem of XOR, as well as in a complex multiagent setting task.
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Scott, H., B. Lechat, A. Reynolds, N. Lovato, P. Escourrou, P. Catcheside e D. Eckert. "O040 Associations between Sleep Irregularity and Hypertension: Sleep Sensor Data from Over Two Million Nights". SLEEP Advances 3, Supplement_1 (1 ottobre 2022): A17. http://dx.doi.org/10.1093/sleepadvances/zpac029.039.
Testo completoAbstract (sommario):
Abstract Introduction Irregular sleep has been associated with worse cardio-metabolic health compared to regular sleep, but prior studies are limited in sample size and have assessed sleep irregularity over short assessment periods (7-14 days). This study investigated associations between sleep irregularity and hypertension in a large, global sample over multiple months. Methods Data from 12,300 participants (Mean ± SD; 50 ± 12 years, 12% females) who used an under-mattress sleep device and a portable blood pressure monitor between July 2020 and March 2021 were included. Each participant had ~180 nights of recordings and ~70 blood pressure entries. Sleep duration regularity was assessed as the standard deviation of device-assessed total sleep time. Sleep timing regularity was assessed as the standard deviation of sleep onset time and sleep midpoint. Logistic regressions were conducted, controlling for age, sex, BMI, and mean total sleep time. Results Across total sleep time quartiles, sleep duration irregularity was consistently associated with a 9-15% increase in hypertension risk. A 38-minute increase in sleep midpoint irregularity was associated with an 11% (1.11 [1.03, 1.20]) increase in hypertension risk, independent of mean total sleep time and mean sleep midpoint. Similarly, a ~31-minute increase in sleep onset time irregularity was associated with a 29% increased risk of hypertension (1.29 [1.18, 1.42]). Conclusions Irregular sleep, regardless of average total sleep time, was associated with increased hypertension risk. Further assessment of day-to-day fluctuations in sleep duration and timing for potential effects on next-day blood pressure and cardiovascular health outcomes is warranted.
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Kulmanakov, Sergey P., e Sergey A. Tyutikov. "Assessment of influence of the Common Rail system high-pressure fuel pump design on regularity of fuel supply to a fuel accumulator". Tractors and Agricultural Machinery 89, n. 4 (27 gennaio 2023): 255–62. http://dx.doi.org/10.17816/0321-4443-108775.
Testo completoAbstract (sommario):
BACKGROUND: At the present time all worldwide diesel engine manufacturers have directed their development strategies on the way of reduction of harmful emissions, fuel efficiency improving and increasing of the power per liter. Using only accumulator type system is not sufficient for the goals achievement. It is necessary to use new auxiliary units, such as an exhaust catalyst, an exhaust recirculation system, injection of additional liquids together with diesel fuel, as well as to improve the existing units. Increasing the accuracy of injection rate of a nozzle will make it possible to adjust the engine fuel system more precisely, that will have a positive effect on all development directions of diesel engine engineering. Injection rate of a nozzle is dependent on fuel pressure in the nozzle inlet and on control signal timing. Pressure pulsation with stable timing cause irregularity of injection rate of a nozzle. Possibility of decreasing of nozzle inlet pressure pulsation is mainly defined by design of a high-pressure fuel pump, as it supplies fuel partially. The design optimization will make it possible to increase the accuracy of injection rate, that will make a positive effect on development of the diesel engines promising areas.
AIMS: Study of irregularity of fuel supply by fuel pumps of various diesel engines designs with the Common Rail fuel accumulation system, aimed to decrease fuel oscillations and to improve stability of injection rate of a nozzle.
METHODS: In order to assess the efficiency of high-pressure fuel pump designs, these designs were simulated in the specialised software. Theoretical studies of fuel supply irregularity for various designs of the pumps were carried out.
RESULTS: Graphs of non-uniformity of fuel supply of high-pressure pumps depending on their design are obtained.
CONCLUSIONS: Based on simulations, the conclusions about design influence on fuel supply irregularity of various designs of pump are made, recommendations for use are given.
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Toffol, Elena, Päivikki Koponen, Riitta Luoto e Timo Partonen. "Pubertal timing, menstrual irregularity, and mental health: results of a population-based study". Archives of Women's Mental Health 17, n. 2 (26 novembre 2013): 127–35. http://dx.doi.org/10.1007/s00737-013-0399-y.
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Witham, Claire L., e Stuart N. Baker. "Information theoretic analysis of proprioceptive encoding during finger flexion in the monkey sensorimotor system". Journal of Neurophysiology 113, n. 1 (1 gennaio 2015): 295–306. http://dx.doi.org/10.1152/jn.00178.2014.
Testo completoAbstract (sommario):
There is considerable debate over whether the brain codes information using neural firing rate or the fine-grained structure of spike timing. We investigated this issue in spike discharge recorded from single units in the sensorimotor cortex, deep cerebellar nuclei, and dorsal root ganglia in macaque monkeys trained to perform a finger flexion task. The task required flexion to four different displacements against two opposing torques; the eight possible conditions were randomly interleaved. We used information theory to assess coding of task condition in spike rate, discharge irregularity, and spectral power in the 15- to 25-Hz band during the period of steady holding. All three measures coded task information in all areas tested. Information coding was most often independent between irregularity and 15–25 Hz power (60% of units), moderately redundant between spike rate and irregularity (56% of units redundant), and highly redundant between spike rate and power (93%). Most simultaneously recorded unit pairs coded using the same measure independently (86%). Knowledge of two measures often provided extra information about task, compared with knowledge of only one alone. We conclude that sensorimotor systems use both rate and temporal codes to represent information about a finger movement task. As well as offering insights into neural coding, this work suggests that incorporating spike irregularity into algorithms used for brain-machine interfaces could improve decoding accuracy.
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Safargaleev, V., A. Kozlovsky, F. Honary, A. Voronin e T. Turunen. "Geomagnetic disturbances on ground associated with particle precipitation during SC". Annales Geophysicae 28, n. 1 (22 gennaio 2010): 247–65. http://dx.doi.org/10.5194/angeo-28-247-2010.
Testo completoAbstract (sommario):
Abstract. We have examined several cases of magnetosphere compression by solar wind pressure pulses using a set of instruments located in the noon sector of auroral zone. We have found that the increase in riometric absorption (sudden commencement absorption, SCA) occurred simultaneously with the beginning of negative or positive magnetic variations and broadband enhancement of magnetic activity in the frequency range above 0.1 Hz. Since magnetic variations were observed before the step-like increase of magnetic field at equatorial station (main impulse, MI), the negative declinations resembled the so-called preliminary impulse, PI. In this paper a mechanism for the generation of PI is introduced whereby PI's generation is linked to SCA – associated precipitation and the local enhancement of ionospheric conductivity leading to the reconstruction of the ionospheric current system prior to MI. Calculation showed that PI polarity depends on orientation of the background electric field and location of the observation point relative to ionospheric irregularity. For one case of direct measurements of electric field in the place where the ionospheric irregularity was present, the sign of calculated disturbance corresponded to the observed one. High-resolution measurements on IRIS facility and meridional chain of the induction magnetometers are utilized for the accurate timing of the impact of solar wind irregularity on the magnetopause.
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Stahl, John S., e Zachary C. Thumser. "Flocculus Purkinje cell signals in mouse Cacna1a calcium channel mutants of escalating severity: an investigation of the role of firing irregularity in ataxia". Journal of Neurophysiology 112, n. 10 (15 novembre 2014): 2647–63. http://dx.doi.org/10.1152/jn.00129.2014.
Testo completoAbstract (sommario):
Mutation of the Cacna1a gene for the P/Q (CaV2.1) calcium channel invariably leads to cerebellar dysfunction. The dysfunction has been attributed to disrupted rhythmicity of cerebellar Purkinje cells, but the hypothesis remains unproven. If irregular firing rates cause cerebellar dysfunction, then the irregularity and behavioral deficits should covary in a series of mutant strains of escalating severity. We compared firing irregularity in floccular and anterior vermis Purkinje cells in the mildly affected rocker and moderately affected tottering Cacna1a mutants and normal C57BL/6 mice. We also measured the amplitude and timing of modulations of floccular Purkinje cell firing rate during the horizontal vestibuloocular reflex (VOR, 0.25–1 Hz) and the horizontal and vertical optokinetic reflex (OKR, 0.125–1 Hz). We recorded Purkinje cells selective for rotational stimulation about the vertical axis (VAPCs) and a horizontal axis (HAPCs). Irregularity scaled with behavioral deficit severity in the flocculus but failed to do so in the vermis, challenging the irregularity hypothesis. Mutant VAPCs exhibited unusually strong modulation during VOR and OKR, the response augmentation scaling with phenotypic severity. HAPCs exhibited increased OKR modulation but in tottering only. The data contradict prior claims that modulation amplitude is unaffected in tottering but support the idea that attenuated compensatory eye movements in Cacna1a mutants arise from defective transfer of Purkinje cell signals to downstream circuitry, rather than attenuated synaptic transmission within the cerebellar cortex. Shifts in the relative sizes of the VAPC and HAPC populations raise the possibility that Cacna1a mutations influence the development of floccular zone architecture.
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Mathew, Gina, David Reichenberger, Orfeu Buxton, Lauren Hale e Anne-Marie Chang. "140 Short and Long Sleep Duration, Poor Sleep Quality, and Later Sleep are Associated with Lower Odds of Adolescents Eating Breakfast". Sleep 44, Supplement_2 (1 maggio 2021): A58. http://dx.doi.org/10.1093/sleep/zsab072.139.
Testo completoAbstract (sommario):
Abstract Introduction Sleep health is linked to dietary choices, and skipping breakfast is associated with risk of negative health outcomes in adolescents. However, there is a lack of research on whether dimensions of sleep at night predict adolescents eating breakfast the next day. We investigated within- and between-person associations of multiple aspects of sleep with adolescent breakfast consumption. Methods Data were collected from a subset of the age 15 wave of the Fragile Families and Child Wellbeing Study (n=590). Teens wore an actigraphy device and completed daily surveys for ~1 week (mean=5.9 days). Surveys assessed subjective sleep quality (low–high) and consumption of breakfast (no/yes). Mixed models assessed whether actigraphy-measured sleep timing (onset, midpoint, and offset) and subjective sleep quality predicted odds of breakfast consumption in both within- and between-person models. A curvilinear association between sleep duration and breakfast consumption was also assessed. Irregularity of sleep duration and timing were tested as additional predictors, calculated as SD per person (in between-person models only). Analyses included random intercepts for participants and covariates: school day, boredom, loneliness, happiness, depressive symptoms, sex, race/ethnicity, body mass index, and household income. Results Within-person analyses revealed a significant curvilinear association between sleep duration and breakfast consumption, such that on nights when teens slept shorter or longer than their average, they had lower odds of eating breakfast the next day (p=.005). Additionally, on nights when teens had a later sleep midpoint or offset than their usual, they tended to skip breakfast the next day (both p<.05). Between-person models showed that teens who on average had later sleep timing (onset, midpoint, and offset) and who reported lower sleep quality had lower odds of eating breakfast (all p<.04). Lastly, teens with greater irregularity of sleep duration and sleep timing (midpoint and offset) had lower odds of eating breakfast (all p<.009). Conclusion Findings indicate that multiple dimensions of adolescent sleep health, including long and short sleep duration, later sleep timing, and poorer sleep quality, are associated with lower odds of eating breakfast. These sleep and dietary behaviors in adolescence may consequently impact future metabolic health. Support (if any) R01HD073352
Tesi sul tema "Timing Irregularity"
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Aghanavesi, Somayeh. "Smartphone-based Parkinson’s disease symptom assessment". Licentiate thesis, Högskolan Dalarna, Mikrodataanalys, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:du-24925.
Testo completoAbstract (sommario):
This thesis consists of four research papers presenting a microdata analysis approach to assess and evaluate the Parkinson’s disease (PD) motor symptoms using smartphone-based systems. PD is a progressive neurological disorder that is characterized by motor symptoms. It is a complex disease that requires continuous monitoring and multidimensional symptom analysis. Both patients’ perception regarding common symptom and their motor function need to be related to the repeated and time-stamped assessment; with this, the full extent of patient’s condition could be revealed. The smartphone enables and facilitates the remote, long-term and repeated assessment of PD symptoms. Two types of collected data from smartphone were used, one during a three year, and another during one-day clinical study. The data were collected from series of tests consisting of tapping and spiral motor tests. During the second time scale data collection, along smartphone-based measurements patients were video recorded while performing standardized motor tasks according to Unified Parkinson’s disease rating scales (UPDRS). At first, the objective of this thesis was to elaborate the state of the art, sensor systems, and measures that were used to detect, assess and quantify the four cardinal and dyskinetic motor symptoms. This was done through a review study. The review showed that smartphones as the new generation of sensing devices are preferred since they are considered as part of patients’ daily accessories, they are available and they include high-resolution activity data. Smartphones can capture important measures such as forces, acceleration and radial displacements that are useful for assessing PD motor symptoms. Through the obtained insights from the review study, the second objective of this thesis was to investigate whether a combination of tapping and spiral drawing tests could be useful to quantify dexterity in PD. More specifically, the aim was to develop data-driven methods to quantify and characterize dexterity in PD. The results from this study showed that tapping and spiral drawing tests that were collected by smartphone can detect movements reasonably well related to under- and over-medication. The thesis continued by developing an Approximate Entropy (ApEn)-based method, which aimed to measure the amount of temporal irregularity during spiral drawing tests. One of the disabilities associated with PD is the impaired ability to accurately time movements. The increase in timing variability among patients when compared to healthy subjects, suggests that the Basal Ganglia (BG) has a role in interval timing. ApEn method was used to measure temporal irregularity score (TIS) which could significantly differentiate the healthy subjects and patients at different stages of the disease. This method was compared to two other methods which were used to measure the overall drawing impairment and shakiness. TIS had better reliability and responsiveness compared to the other methods. However, in contrast to other methods, the mean scores of the ApEn-based method improved significantly during a 3-year clinical study, indicating a possible impact of pathological BG oscillations in temporal control during spiral drawing tasks. In addition, due to the data collection scheme, the study was limited to have no gold standard for validating the TIS. However, the study continued to further investigate the findings using another screen resolution, new dataset, new patient groups, and for shorter term measurements. The new dataset included the clinical assessments of patients while they performed tests according to UPDRS. The results of this study confirmed the findings in the previous study. Further investigation when assessing the correlation of TIS to clinical ratings showed the amount of temporal irregularity present in the spiral drawing cannot be detected during clinical assessment since TIS is an upper limb high frequency-based measure.
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Cissoko, Mamadou Ben Hamidou. "Adaptive time-aware LSTM for predicting and interpreting ICU patient trajectories from irregular data". Electronic Thesis or Diss., Strasbourg, 2024. https://publication-theses.unistra.fr/restreint/theses_doctorat/2024/CISSOKO_MamadouBenHamidou_2024_ED269.pdf.
Testo completoAbstract (sommario):
En médecine prédictive personnalisée, modéliser avec précision la maladie et les processus de soins d'un patient est crucial en raison des dépendances temporelles à long terme inhérentes. Cependant, les dossiers de santé électroniques (DSE) se composent souvent de données épisodiques et irrégulières, issues des admissions hospitalières sporadiques, créant des schémas uniques pour chaque séjour hospitalier.Par conséquent, la construction d'un modèle prédictif personnalisé nécessite une considération attentive de ces facteurs pour capturer avec précision le parcours de santé du patient et aider à la prise de décision clinique.LSTM sont efficaces pour traiter les données séquentielles comme les DSE, mais ils présentent deux limitations majeures : l'incapacité à interpréter les résultats des prédictions et à prendre en compte des intervalles de temps irréguliers entre les événements consécutifs. Pour surmonter ces limitations, nous introduisons de nouveaux réseaux neuronaux à mémoire dynamique profonde appelés Multi-Way Adaptive et Adaptive Multi-Way Interpretable Time-Aware LSTM (MWTA-LSTM etAMITA), conçus pour les données séquentielles collectées de manière irrégulière.L'objectif principal des deux modèles est de tirer parti des dossiers médicaux pour mémoriser les trajectoires de maladie et les processus de soins, estimer les états de maladie actuels et prédire les risques futurs, offrant ainsi un haut niveau de précision et de pouvoir prédictifIn personalized predictive medicine, accurately modeling a patient's illness and care processes is crucial due to the inherent long-term temporal dependencies. However, Electronic Health Records (EHRs) often consist of episodic and irregularly timed data, stemming from sporadic hospital admissions, which create unique patterns for each hospital stay. Consequently, constructing a personalized predictive model necessitates careful consideration of these factors to accurately capture the patient's health journey and assist in clinical decision-making. LSTM networks are effective for handling sequential data like EHRs, but they face two significant limitations: the inability to interpret prediction results and to take into account irregular time intervals between consecutive events. To address limitations, we introduce novel deep dynamic memory neural networks called Multi-Way Adaptive and Adaptive Multi-Way Interpretable Time-Aware LSTM (MWTA-LSTM and AMITA) designed for irregularly collected sequential data. The primary objective of both models is to leverage medical records to memorize illness trajectories and care processes, estimate current illness states, and predict future risks, thereby providing a high level of precision and predictive power
Atti di convegni sul tema "Timing Irregularity"
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Ohsuga, Mieko, e Hidenori Boutani. "Detection of a Decrease in Concentration Using Indices Derived from Heart Rate and Respiration Toward Affective Human-Robot Interaction". In Applied Human Factors and Ergonomics Conference. AHFE International, 2021. http://dx.doi.org/10.54941/ahfe100641.
Testo completoAbstract (sommario):
The present paper refers the method to detect the degraded concentration of human who is engaged in computer work or watching television in order to find the appropriate timing for robot’s interrupt. The heart rate and respiratory measures were confirmed to change depending on the degree of concentration by an experiment. Principle component analysis was applied and two measure components were selected and rotated by the varimax method. The first principle component represented large low frequency component of heart rate variability (HRV), low respiratory frequency and large respiratory irregularity, while the second component represented high heart rate, small high frequency component of HRV. It was suggested that the first principle component can be used to discriminate between concentrated and degraded concentrated sates of human.
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GENTILI, Roberto, Stefania ZANFORLIN, Stefano FRIGO, Francesco COZZOLINO, Pierluigi DELL'ORTO e Carlo DOVERI. "16 Optimisation of a Stratified Charge Strategy for a Direct Injected Two-Stroke Engine". In Small Engine Technology Conference & Exposition. 10-2 Gobancho, Chiyoda-ku, Tokyo, Japan: Society of Automotive Engineers of Japan, 2002. http://dx.doi.org/10.4271/2002-32-1785.
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<div class="htmlview paragraph">Direct fuel injection is becoming mandatory in two-stroke S.I. engines, since it prevents one of the major problems of these engines, that is fuel loss from the exhaust port. Another important problem is combustion irregularity at light loads, due to excessive presence of residual gas in the charge, and can be solved by charge stratification.</div> <div class="htmlview paragraph">High-pressure liquid fuel injection is able to control the mixing process inside the cylinder for getting either stratified charge at partial loads or quasi-stoichiometric conditions, as it is required at full load. This paper shows the development of this solution for a small engine for moped and light scooter, using numeric and experimental tools. In order to obtain the best charge characteristics at every load and engine speed, different combustion chambers have been conceived and studied, examining the effects of combustion chamber geometry, together with injector position and injection timing</div>
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Small, Evan, John Reifenberg, Yizhang Yang, Sadegh M. Sadeghipour e Mehdi Asheghi. "Numerical Simulation of Mark Formation/Erasure in Phase Change Recording". In ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72330.
Testo completoAbstract (sommario):
Design/optimization of the phase change recording media to create proper marks, in size, shape, and quality, needs a robust modeling tool to predict temperature distribution in the constituting layers and model the phase formation during writing/erasure of the information bits. This requires a modeling of the heat transfer (thermal performance) and the crystallization processes. The thermal modeling, which is based on the solution of the heat diffusion equation for finding temperature distribution in the multilayer media, has been done before, using the finite difference techniques. These techniques have limited potentials for modeling real phase change recording media that have a rather more complex geometry. The finite elements method has, on the other hand, the required flexibility for such applications. In this work, we are reporting on development of a numerical simulation tool that uses the finite elements method for heat transfer simulation. ANSYS is used as the source code for the heat transfer simulation, in this application, with the crystallization model then being built into this media. This code has been used to simulate mark formation during writing on grooved plain and planer patterned media. Patterning the phase change material layer looks very promising in controlling the mark size and the mark edge irregularity which lead to timing jitter.
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Vernotte, F. "Spectral analysis of irregularly spaced timing data: comparison of several methods". In 10th International Conference on European Frequency and Time. IEE, 1996. http://dx.doi.org/10.1049/cp:19960073.
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