Given a configuration of pebbles on the vertices of a graph, a pebbling move is defined by removing two pebbles from some vertex and placing one pebble on an adjacent vertex. The cover pebbling number of a graph, γ (G), is the smallest number of pebbles such that through a sequence of pebbling moves, a pebble can eventually be placed on every vertex simultaneously, no matter how the pebbles are initially distributed. We determine Bose-Einstein and Maxwell-Boltzmann cover pebbling thresholds for the complete graph. Also, we show that the cover pebbling decision problem is NP-complete.

We obtain first-order cover pebbling thresholds of the complete graph for Maxwell Boltzmann and Bose Einstein configurations.

Given a configuration of t indistinguishable pebbles on the n vertices of a graph G, we say that a vertex v can be reached if a pebble can be placed on it in a finite number of "moves". G is said to be pebbleable if all its vertices can be thus reached. Now given the n-path Pn how large (resp. small) must t be so as to be able to pebble the path almost surely (resp. almost never)? It was known that the threshold th(Pn) for pebbling the path satisfies n2clgn≤th(Pn)≤n22lgn, where lg=log2 and c<1/2 is arbitrary. We improve the upper bound for the threshold function to th(Pn)≤n2dlgn, where d>1 is arbitrary.

BACKGROUND: Previous research has shown that the ventilatory threshold (VT) correlates highly with onset of lactate accumulation and maximal steady-state exercise (MSS) level. Also, studies have shown the VT is useful in prescribing exercise for cardiac patients in that it gives an exercise intensity at which the patient is metabolically stable. METHODS: The purpose of this study was to determine if a MSS response could be achieved at an exercise intensity corresponding to the VT for patients with CAD. A group of 31 patients with CAD performed a maximal effort treadmill exercise test in which respiratory gas exchange was measured. The VT was determined using the V-slope method of computer regression analysis of the plot of carbon dioxide production versus oxygen consumption. Subjects then performed a constant load treadmill test a speed and grade that corresponded to the VT. Heart rate (HR), systolic blood pressure (SBP), and rating of perceived exertion (RPE) evaluated for steady-state responses. If subjects showed a steady-state response in two of these three parameters they were scored as having achieved a maximal steady-state (MSS+) response; those not meeting this standard were scored as failing to achieve maximal steady-state (MSS-) response. Subjects were analyzed as an entire group (N=31), as well as analyzed in subsets according to history of myocardial infarction (MI+, N=20; MI-, N=11) and administration of beta-blocker medications (BB+, N=16; BB-, N=15). RESULTS: Overall, subjects demonstrated significantly more MSS+ responses than MSS- responses (80% Vs 20%, P<0.05). Analysis of the subgroup data showed that it was the patient s with a history of MI (MI+ =85%, P<0.05) and those not receiving beta-blocker medications (BB- = 93%, P<0.05) who had significantly greater proportions of subject achieving MSS+ responses in the fixed load exercise condition. Conversely patient in the MI- (73 %, P < 0.05) and BB (69% P < 0.05) groups showed no significant differences in the number of MSS+ and MSS- responses. CONCLUSIONS: The VT, as measured during ramp exercise testing on the treadmill, provided a basis for establishing a maximal steady-state load in terms of cardiovascular and perceptual variables for 80% of the patients in the CAD study group. The measurements of HR, SBP, and RPE are easily obtained in a clinical setting and thus enable the VT to be used in bringing about a more efficacious exercise prescription. The validity of this method may be questioned, however, for patient with out a history of MI and for those receiving beta-blocker medications. / Master of Science

Le Grand-Tunis présente une vulnérabilité face à la pollution atmosphérique compte tenu des fortes densités de population et des nombreuses infrastructures caractérisant son territoire. L’ozone (O3) et les particules en suspension (PM10) dépassent fréquemment les normes tunisiennes relatives à ces polluants. Quant aux normes internationales fixées par l’OMS (Organisation Mondiale de la Santé), elles n’ont été respectées que rarement. L’appareil respiratoire constitue une voie d’exposition privilégiée aux agressions en rapport avec l’environnement. De nombreuses pathologies pulmonaires sont directement liées à l’inhalation des polluants dans l’atmosphère. Les influences des mécanismes climatiques sur la santé respiratoire sont très étendues également, notamment les épisodes météorologiques extrêmes appelés aussi paroxysmes météorologiques.L’objectif principal de cette thèse est de caractériser l’impact des facteurs environnementaux, climat et polluants atmosphériques sur la santé respiratoire dans le Grand-Tunis. Nous avons choisi de quantifier cette relation à partir des indicateurs biométéorologiques et des seuils absolus de stress météorologique, spécifiques au climat tunisois, et de la qualité de l’air pour prévoir des épisodes à risque pour la santé respiratoire. Cela est fait à partir des extrêmes météorologiques des paramètres les plus irritants pour la santé respiratoire : la température, l’humidité relative de l’air et la vitesse maximale du vent. Nous avons aussi établi des normes réalistes pour la qualité de l’air, relatives à l’O3 et aux PM10, identifiant les seuils critiques de surplus des hospitalisations dans le Grand-Tunis et qui peuvent être appliquées dans tout le pays. Compte tenu de l’effet de certains paramètres climatiques sur la dispersion des polluants dans l’atmosphère, nous avons aussi étudié la relation entre les paramètres météorologiques et les polluants d’O3 et de PM10. Les résultats de cette étude révèlent que, durant toute l’année, les tunisois sont confrontés au moins à un risque environnemental : la pollution photochimique et les vagues de chaleur, très répandues durant la saison chaude ; durant la saison froide, c’est le risque du froid et de la pollution particulaire ; et pendant les intersaisons, c’est la pollution biologique, avec les pollens, qui est le risque le plus important. Toutefois, l’exposition à court terme à ces risques, sur l’aggravation de la maladie respiratoire ou l’irritation du système respiratoire sont bien réelles. Cette recherche montre que le développement et l’aggravation des maladies respiratoires semblent découler d’une interaction complexe entre divers facteurs individuels et environnementaux. Ils sont essentiellement en relation avec le temps, la qualité de l’air et l’atopie. L’importance de ces facteurs varie selon la maladie considérée. Par ailleurs, le faible niveau socioéconomique de la famille augmente la probabilité d’être exposé à plusieurs de ces facteurs de risque. À cela s’ajoutent les facteurs comportementaux tels que l’alcool, le tabagisme actif et passif. / The Greater metropolitan area of Tunis, often referred to as Grand Tunis or Tunis, presents a vulnerability to air pollution due to the high concentrations of population and the infrastructures characterizing its territory. Ozone (O3) and particles (PM10) often exceed the Tunisian thresholds for these pollutants. As for the international standards set by the WHO (world health organization), they have not been met infrequently.The respiratory tract is a preferred route of exposure to aggressions related to the environment. Many lung diseases are directly linked to inhalation of pollutants in the atmosphere. The influences of climate mechanisms on respiratory health are also very extensive, including extreme weather events, also called weather paroxysms.The main objective of this thesis was to characterize the impact of environmental factors, climate and atmospheric pollutants on respiratory health in Grand Tunis. We have chosen to quantify this relationship from the biometeorological indicators and absolute thresholds of meteorological stress, specific Tunisian climate, and air quality to predict episodes at risk for respiratory health and thresholds of weather variables and air quality resulting in excess hospital admissions for respiratory causes. And this from the climate extremes of the parameters affecting the respiratory health : temperature, relative humidity and maximum wind speed. We, too, set realistic standards for air quality, relative to O3 and PM10, identifying critical thresholds excess hospitalizations in Grand Tunis and can be applied throughout the country. Given the effect of some climatic parameters on the dispersion of pollutants in the atmosphere, we also studied the relationship between climatic parameters and pollutants of O3 and PM10. The results of this study reveal that, throughout the year, Tunisians are confronted with at least an environmental risk : photochemical pollution and heat waves, which are very responsive during the hot season ; during the cold season, it is the risk of cold and particulate pollution; and during the off-season, biological pollution, together with pollen, is more at risk. However, short-term exposure to these risks, the worsening of the respiratory illness or irritation of the respiratory system is real. This study showed that the development and worsening of respiratory diseases appear to result from a complex interplay of individual and environmental factors. They are mainly in relation to time, air quality and atopy. The importance of these factors varies the respective disease. Moreover, the low socioeconomic status of the family increases the likelihood of being exposed to more of these risk factors. Added to this are behavioral factors such as alcohol, active and passive smoking.

Sporadic problems with pink color defect, or pinking, has occurred in cooked meat products for decades. Pink color can be due to the presence of undenatured myoglobin, denatured globin hemochromes, or nitrosylhemochrome. This research documented the level of added nitrite that produced nitrosylhemochrome in processed meat rolls from fabricated beef round, pork shoulder, turkey breast, and chicken breast. For each meat type, preliminary studies were conducted to narrow the range at which added nitrite caused pinking. Subsequently, the nitrite levels were increased incrementally by 1-ppm, and pink color was measured by trained panelists and by a Hunter color meter. Nitrosylhemochrome content was determined by acetone extraction. Panel and instrumental measurements identified pink color in beef samples formulated with 14-ppm nitrite; nitrosohemochrome extracts detected pigment at 12- ppm. Nitrite levels that caused pinking in pork shoulder were much lower than in beef. Panelists identified pink color at 4-ppm nitrite, and Hunter color meter values showed increased redness at 6-ppm. Pigment extraction detected nitrosylhemochrome at 4- ppm added nitrite. The trained panel and Hunter color meter detected pink color in turkey breast at 2-ppm added nitrite; nitrosohemochrome extraction detected pink pigment at 3-ppm added nitrite. In chicken breast, pink color was detected visually and instrumentally at 1-ppm added nitrite. Pigment extraction detected nitrosylhemochrome at 2-ppm added nitrite. Lower levels of nitrite (1-3-ppm) caused pinking in light-colored meats (turkey and chicken breast, meats with total pigment between 19-ppm and 27-ppm). Higher levels of nitrite (5-14-ppm) caused pink color defect in dark pigmented meat (beef round and pork shoulder, meats with total pigment levels between 56-ppm and 147-ppm). Regression analysis was used to relate total pigment and the minimum level of nitrite causing pinking. The minimum nitrite level causing pinking was the lowest level of nitrite at which the trained panel, acetone extraction, and instrumental results detected pink color or nitrosyl pigment. The formula obtained from the model was as follows: Y = 0.092X + 0.53, where "Y" is the minimum level of added nitrite to cause pinking and "X" is the total pigment of the meat. This formula can be used to estimate the level of nitrite that can be expected to cause pinking in a wide range of pigmented meats.

No description available.

Shrinking minimum feature size in deep sub-micron has made fabrication of progressively faster devices possible. The performance of interconnects has been a bottleneck in determining the overall performance of a chip. A reliable high-speed communication technique is necessary to improve the performance of on-chip communication. Recent publications have demonstrated that use of multiple threshold voltages improves the performance of a bus significantly. The multi-threshold capture mechanism takes advantage of predictable temporal behavior of a tightly coupled bus to predict the next state of the bus early. However, Use of multiple threshold voltages also reduces the voltage slack and consequently increases the susceptibility to noise. Reduction in supply voltage exacerbates the situation. This work proposes a novel error detection and correction encoding technique that takes advantage of the high performance of the multi-threshold capture mechanism as well as its inbuilt redundancy to achieve reliable high-speed communication while introducing considerably less amount of redundancy as compared to the conventional methods. The proposed technique utilizes graph-based algorithms to produce a set of valid code words. The algorithm takes advantage of implicit set operations using binary decision diagram to improve the scalability of the code word selection process. The code words of many crosstalk avoidance codes including the proposed error detection and correction technique exhibit a highly structured behavior. The sets of larger valid code words can be recursively formed using the sets of smaller valid code words. This work also presents a generalized framework for scalable on-chip code word generation. The proposed CODEC implementation strategy uses a structured graph to model the recursive nature of an encoding technique that facilitates scalable CODEC implementation. The non-enumerative nature of the implementation strategy makes it highly scalable. The modular nature of the CODEC also simplifies use of pipelined architecture thereby improving the throughput of the bus.

Compressed sensing is an emerging approach for signal acquisition wherein theory has shown that a small number of linear, random projection of a signal contains enough information for reconstruction of the signal. Despite its potential to enable lightweight and inexpensive sensing hardware that simultaneously combines signal acquisition and dimensionality reduction, the compressed sensing of images and video still entails several challenges, in particular, a sensing-measurement operator which is difficult to apply in practice due to the heavy memory and computational burdens. Block-based random image sampling coupled with a projection-driven compressed-sensing recovery is proposed to address this challenge. For images, the block-based image acquisition is coupled with reconstruction driven by a directional transform that encourages spatial sparsity. Specifically, both contourlets as well as complex-valued dual-tree wavelets are considered for their highly directional representation, while bivariate shrinkage is adapted to their multiscale decomposition structure to provide the requisite sparsity constraint. Smoothing is achieved via a Wiener filter incorporated into iterative projected Landweber compressed-sensing recovery, yielding fast reconstruction. Also considered is an extension of the basic reconstruction algorithm that incorporates block-based measurements in the domain of a wavelet transform. The pro-posed image recovery algorithm and its extension yield images with quality that matches or exceeds that produced by a popular, yet computationally expensive, technique which minimizes total variation. Additionally, reconstruction quality is substantially superior to that from several prominent pursuits-based algorithms that do not include any smoothing. For video, motion estimation and compensation is utilized to promote temporal sparsity. Because video sequences have temporal redundancy in locations in which objects are moving while the background is still, a residual between the current frame and the previous frame compensated by object motion is shown to be more sparse than the orig-inal frame itself. By using residual reconstruction, information contained in the previous frame contributes to the reconstruction of the current frame. The proposed block-based compressed-sensing reconstruction for video outperforms a simple frame-byrame reconstruction as well as a 3D volumetric reconstruction in terms of visual quality. Finally, quantization of block-based compressed-sensing measurements is considered in order to generate a true bitstream from a compressed-sensing image acquisition. Specifically, a straightforward process of quantization via simple uniform scalar quantization applied in conjunction with differential pulse code modulation of the block-based compressed-sensing measurements is proposed. Experimental results demonstrate significant improvement in rate-distortion performance as compared scalar quantization used alone in several block-based compressed-sensing reconstruction algorithms. Additionally, rate-distortion performance superior to that of alternative quantized-compressed-sensing techniques relying on optimized quantization or reconstruction is observed.

Threshold Logic technology is conceived as the crucial alternate emerging technology to CMOS implementation in nanoelectronic era and the realization of complex functionalities is becoming an increasingly promising approach in the deep sub-micron design era. The gate that is implemented with threshold logic is called a Threshold Logic Gate (TLG). The logic output value of a Threshold Logic Gate (TLG) depends on the weighted sum of its inputs. Manufactured weights in the threshold logic gates (TLGs) may differ from the designed values and significantly affects the fault coverage. A novel fault model for weight defects is proposed. Also an Automatic Test Pattern Generation (ATPG) tool has been implemented that uses the fault model to detect whether the circuit is malfunctioning due to such weight-related defects. A novel design methodology is presented in this work to design complex TLG networks that are tolerant to manufacturing shortcomings. It uses a procedure to identify the optimum fault tolerant design of any given k-input TLG. Extensive research has been done in the development of synthesis methodologies in the past, predominantly greedy. A fault tolerance aware synthesis methodology is proposed.