Direct Solution of the Inverse Stochastic Problem through Elementary Markov State Disaggregation

Existing methods to find the eigenvalue spectrum (or a reasonable approximation to it) of square matrices can be extended to Stochastic Matrices (SM). The matter is more delicate for the Inverse Eigenvalue Problem (IEP), which consists in the reconstruction of a matrix from a given eigenvalue spectrum. In this work, we present a simple method to solve a real-valued IEP for SM by constructing step-by-step the solution matrix through an elementary Markov state disaggregation method named state splitting, and based on a matrix operator. After showing some results on how the splitting operator influences the steady-state distribution of the Markov chain associated with the SM, we demonstrate that the state splitting operator has a fundamental property: when applied to a SM A of size n-by-n, it yields a SM of size (n+1)-by-(n+1), whose eigenvalue spectrum is equal to that of A, plus an additional eigenvalue belonging to a bounded interval. We use a constructive method to prove that for any spectrum made of real and positive eigenvalues, one can build up an infinite number of SM sharing this spectrum. Finally, we present a new sufficient condition to test if a given set of real values can be the spectrum of a SM constructed by the proposed method

Sustained Self-Regulation of Energy Intake: Initial Hunger Improves Insulin Sensitivity

Background. Excessive energy intake has been implicated in diabetes, hypertension, coronary artery disease, and obesity. Dietary restraint has been unsuccessful as a method for the self-regulation of eating. Recognition of initial hunger (IH) is easily learned, can be validated by associated blood glucose (BG) concentration, and may improve insulin sensitivity. Objective. To investigate whether the initial hunger meal pattern (IHMP) is associated with improved insulin sensitivity over a 5-month period. Methods. Subjects were trained to recognize and validate sensations of IH, then adjust food intake so that initial hunger was present pre-meal at each meal time (IHMP). The purpose was to provide meal-by-meal subjective feedback for self-regulation of food intake. In a randomised trial, we measured blood glucose and calculated insulin sensitivity in 89 trained adults and 31 not-trained controls, before training in the IHMP and 5 months after training. Results. In trained subjects, significant decreases were found in insulin sensitivity index, insulin and BG peaks, glycated haemoglobin, mean pre-meal BG, standard deviation of diary BG (BG as recorded by subjects' 7-day diary), energy intake, BMI, and body weight when compared to control subjects. Conclusion. The IHMP improved insulin sensitivity and other cardiovascular risk factors over a 5-month period

Contributi per una flora vascolare di toscana. IX (507-605)

Contributions for a vascular flora of Tuscany. IX (507-605). New localities and/or confirmations concerning 98 specific and subspecific plant taxa of Tuscan vascular flora, belonging to 81 genera and 42 families are presented: Alisma, Baldellia (Alismataceae), Chenopodium (Amaranthaceae), Sternbergia (Amaryllidaceae), Bupleurum (Apiaceae), Vinca (Apocynaceae), Muscari, Polygonatum (Asparagaceae), Carlina, Centaurea, Chondrilla, Filago, Pallenis, Tagetes, Tr a - gopogon, Tyrimnus (Asteraceae), Impatiens (Balsaminaceae), Campsis (Bignoniaceae), Cardamine, Iberis, Isatis, Lepidium, Rorippa (Brassicaceae), Humulus (Cannabaceae), Centranthus (Caprifoliaceae), Atocion, Paronychia, Sabulina, Scleranthus (Caryophyllaceae), Euonymus (Celastraceae), Fumana (Cistaceae), Phedimus, Sedum (Crassulaceae), Juniperus (Cupressacesae), Carex, Cyperus, Schoenus (Cyperaceae), Erica (Ericaceae), Euphorbia (Euphorbiaceae), Astragalus, Cytisus, Gleditsia, Lotus, Trifolium, Vicia (Fabaceae), Geranium (Geraniaceae), Philadelphus (Hydrangeaceae), Phacelia (Hydrophyllaceae), Hermodactylus, Iris, Romulea (Iridaceae), Salvia, Ziziphora (Lamiaceae), Gagea, Lilium (Liliaceae), Lindernia (Linderniaceae), Mirabilis (Nyctaginaceae), Nymphaea (Nymphaeaceae), Ligustrum (Oleaceae), Oenothera (Onagraceae), Oxalis (Oxalidaceae), Plantago, Veronica (Plantaginaceae), Armeria (Plumbaginaceae), Eleusine, Festuca, Phleum, Setaria, Stipa, Tragu s (Poaceae), Stuckenia (Potamogetonaceae), Anemonoides, Ranunculus (Ranunculaceae), Reseda (Resedaceae), Aphanes, Cotoneaster, Eriobotrya, Malus, Rosa (Rosaceae), Galium (Rubiaceae), Nicotiana, (Solanaceae). In the end, the conservation status of the units and possible protection of the cited biotopes are discussed

Contributi per una flora vascolare di Toscana. VIII (440-506)

New localities and/or confirmations concerning 67 specific and subspecific plant taxa of Tuscan vascular flora, belonging to 59 genera and 37 families are presented: Alisma (Alismataceae), Amaranthus (Amaranthaceae), Leucojum, Sternbergia, Tristagma (Amaryllidaceae), Aloe (Asphodelaceae), Erigeron, Galinsoga, Hieracium, Rhagadiolus, Silybum, Soliva, Taraxacum (Asteraceae), Impatiens (Balsaminaceae), Berberis (Berberidaceae), Cardamine (Brassicaceae), Opuntia (Cactaceae), Cephalaria, Sixalix, Succisa (Caprifoliaceae), Silene (Caryophyllaceae), Convolvulus, Ipomoea (Convolvulaceae), Aeonium (Crassulaceae), Scirpus (Cyperaceae), Equisetum (Equisetaceae), Euphorbia (Euphorbiaceae), Astragalus, Trifolium (Fabaceae), Quercus (Fagaceae), Crocus (Iridaceae), Juncus (Juncaceae), Utricularia (Lentibulariaceae), Peplis (Lythraceae), Maclura (Moraceae), Nymphaea (Nymphaeaceae), Oenothera (Onagraceae), Anacamptis, Orchis (Orchidaceae), Orobanche (Orobanchaceae), Callitriche, Veronica (Plantaginaceae), Alopecurus, Eleusine, Glyceria, Phleum (Poaceae), Persicaria, Polygonum (Polygonaceae), Groenlandia (Potamogetonaceae), Clematis, Pulsatilla, Ranunculus (Ranunculaceae), Rhamnus (Rhamnaceae), Fragaria, Potentilla, Pyracantha (Rosaceae), Galium (Rubiaceae), Sparganium (Typhaceae), Vitis (Vitaceae). In the end, the conservation status of the units and eventual protection of the cited biotopes are discussed

Contributi per una flora vascolare di Toscana. VIII (440-506) [Contributions for a vascular flora of Tuscany. VIII (440-506)]

Contributions for a vascular flora of Tuscany. VIII (440-506). New localities and/or confirmations concerning 67 specific and subspecific plant taxa of Tuscan vascular flora, belonging to 59 genera and 37 families are presented: Alisma (Alismataceae), Amaranthus (Amaranthaceae), Leucojum, Sternbergia, Tristagma (Amaryllidaceae), Aloe (Asphodelaceae), Erigeron, Galinsoga, Hieracium, Rhagadiolus, Silybum, Soliva, Taraxacum (Asteraceae), Impatiens (Balsaminaceae), Berberis (Berberidaceae), Cardamine (Brassicaceae), Opuntia (Cactaceae), Cephalaria, Sixalix, Succisa (Caprifoliaceae), Silene (Caryophyllaceae), Convolvulus, Ipomoea (Convolvulaceae), Aeonium (Crassulaceae), Scirpus (Cyperaceae), Equisetum (Equisetaceae), Euphorbia (Euphorbiaceae), Astragalus, Trifolium (Fabaceae), Quercus (Fagaceae), Crocus (Iridaceae), Juncus (Juncaceae), Utricularia (Lentibulariaceae), Peplis (Lythraceae), Maclura (Moraceae), Nymphaea (Nymphaeaceae), Oenothera (Onagraceae), Anacamptis, Orchis (Orchidaceae), Orobanche (Orobanchaceae), Callitriche, Veronica (Plantaginaceae), Alopecurus, Eleusine, Glyceria, Phleum (Poaceae), Persicaria, Polygonum (Polygonaceae), Groenlandia (Potamogetonaceae), Clematis, Pulsatilla, Ranunculus (Ranunculaceae), Rhamnus (Rhamnaceae), Fragaria, Potentilla, Pyracantha (Rosaceae), Galium (Rubiaceae), Sparganium (Typhaceae), Vitis (Vitaceae). In the end, the conservation status of the units and eventual protection of the cited biotopes are discussed

Error Correction Improvement based on Weak-Bit-Flipping for Resistive Memories

International audienceResistive memories are affected by significant error rates tied to structural relaxation and wear out of the resistive memory devices. A way to reduce the need for strong errorcorrecting codes (ECCs) is to improve error correction based on the weak bits, i.e., potentially faulty bits, identified in sensed memory words. Here, it is formally proven that conventional ECC decoders reinforced with weak-bit-flipping may achieve similar error correction capability as theoretical generalized minimum-distance decoders. It is shown that weak-bit-flipping may reduce the uncorrectable bit error rate (UBER) by orders of magnitude when applied in conjunction with single-errorcorrecting and double-error-detecting (SEC-DED) or double error-correcting and triple-error-detecting (DEC-TED) codes. In particular, weak-bit-information extracted from a 2T2R memory and used to reinforce a DEC-TED code with a conventional decoder may enable an UBER that is one order of magnitude better than the UBER achieved with a triple-errorcorrecting (TEC) code and a conventional decoder

Experimental Analysis on the Effects of Passive Prechambers on a Small 2-Stroke Low-Pressure Direct Injection (LPDI) Engine

Two-stroke (2S) engines still play a key role in the global internal combustion engine (ICE) market when high power density, low production costs, and limited size and weight are required. However, they suffer from low efficiency and high levels of pollutant emissions, both linked to the short circuit of fuel and lubricating oil. Low- and high-pressure direct injection systems have proved to be effective in the reduction of fuel short circuiting, thus decreasing unburnt hydrocarbons and improving engine efficiency. However, the narrow time window available for fuel to be injected and homogenized with air, limited to few crank-angles, leads to insufficiently homogenized fuel-air mixtures and, as a consequence, to incomplete combustions. The use of prechambers can be a well-suited solution to avoid these issues. In fact, the faster combustion which results from the ignition process by hot turbulent jets, allows us to delay the ignition advance, thus achieving a more homogenous mixture inside the combustion chamber; furthermore, the improved mixing process which occurs inside the prechamber extends the lean flammability limit of the engine. The present paper shows the preliminary experimental results of the use of passive prechambers on a crank-scavenged Low-Pressure Direct Injection (LPDI) 2S 50 cm3 engine for motorcycle use. Analyses were carried out at full load conditions in order to understand the effects of adopting a prechamber on the engine performance, in terms of Indicating Mean Effective Pressure (IMEP), heat release, and cycle-to-cycle variation. Diameter of orifices was varied so as to achieve best performance on the investigated engine. Results prove that a faster and more effective combustion process can be achieved in the LPDI engine. Furthermore, the analysis highlights the importance of choosing the right flow-passage area of orifices, which is related to the prechamber volume, to avoid excessive in-cylinder pressure peaks or a too early pressure decrease during the expansion phase

Jet ignition in small two-stroke engines: an experimental survey on benefits and challenges

Increasingly stringent policy on carbon dioxide have proved to be a severe constraint on the design of light two-stroke (2S) engines. The enhancement of efficiency is claimed to be the main target to make these devices compliant with future regulations. Low-Pressure Direct Injection (LPDI) was found to be effective in the reduction of fuel short circuit, thus improving efficiency and mitigating pollution. Innovative combustion technologies are required to exploit further the fuel potential. Jet Ignition (JI), i.e., ignition provided by means of hot turbulent jets, was found to improve the fuel ignition process, leading to a faster and more uniform combustion. Several benefits are shown in over forty years of Literature, from the higher performance to wider flammability limits. However, few studies have been performed on small 2S engines, for which only full-load data are available. This paper aims at experimentally evaluating benefits and challenges of adopting the JI technology on light 2S LPDI engines at both full- and low- load operation. Different configurations of passive prechambers have been investigated in terms of indicated cycle, brake efficiency and cycle-to-cycle variation. A sensitivity analysis on the spark timing was performed to fine-tune the combustion process. Results show the adequacy of the JI for use in devices operating close to full torque, like garden tools; however, issues related to the excessive amount of residual gas or to the rapid pressure decrease during the expansion phase were highlighted. Different solutions for solving these challenges are proposed

Proposal of a new ultra low leakage 10T sub threshold SRAM bitcell

International audienceThe tendency for low energy consumption in systems-on-chip results in a need for memories operating in the near- and sub-threshold regions. This paper gives a comparative study of Static Random Access Memory (SRAM) bitcells working under Ultra-Low Voltage in 32nm CMOS. A new 10T SRAM bitcell is then proposed and features low leakage current. It is capable of operation under ULV (~300mV) and allows bit-interleaving technique that is critical to cope with multiple bit soft-errors for reducing dynamic and static power consumption compared to state-of-the-art bitcells

Impact of Random Telegraph Signals on 6T high-density SRAM in 28nm UTBB FD-SOI

session A7L-E: Advanced CMOSInternational audienceThis work investigates the impact of Random Telegraph Signal (RTS) noise on a 6 Transistors single P-well Static Random Access Memory (6T-SRAM) manufactured in 28nm Ultra-Thin Body and Buried Oxide Fully-Depleted Silicon-On-Insulator (UTBB FD-SOI) technology. A SPICE-level bias-and time-dependent RTS model peculiar to UTBB FD-SOI, which considers both front- and back-gate of the device as RTS sources, is presented. The Bit-Error-Rate is evaluated on silicon dies through the write-ability (WA) failure criterion and with a dedicated back-biasing strategy. Simulations evidence the role of RTS-induced dynamic variability with respect to process variability and show a good agreement with measurements