Modélisation probabiliste d'impression à l'échelle micrométrique

We develop the probabilistic models of the print at the microscopic scale. We study the shape randomness of the dots that originates the prints, and the new models could improve many applications such as the authentication. An analysis was conducted on various papers, printers. The study shows a large variety of shape that depends on the printing technology and paper. The digital scan of the microscopic print is modeled in: the gray scale distribution, and the spatial binary process modeling the printed/blank spatial distribution. We seek the best parametric distribution that takes account of the distributions of the blank and printed areas. Parametric distributions are selected from a set of distributions with shapes close to the histograms and with the Kolmogorov-Smirnov divergence. The spatial binary model handles the wide diversity of dot shape and the range of variation of spatial density of inked particles. At first, we propose a field of independent and non-stationary Bernoulli variables whose parameters form a Gaussian power. The second spatial binary model encompasses, in addition to the first model, the spatial dependence of the inked area through an inhomogeneous Markov model. Two iterative estimation methods are developed; a quasi-Newton algorithm which approaches the maximum likelihood and the Metropolis-Hasting within Gibbs algorithm that approximates the minimum mean square error estimator. The performances of the algorithms are evaluated and compared on simulated images. The accuracy of the models is analyzed on the microscopic scale printings coming from various printers. Results show the good behavior of the estimators and the consistency of the models.Nous développons des modèles probabilistes pour l’impression à l’échelle micrométrique. Tenant compte de l’aléa de la forme des points qui composent les impressions, les modèles proposés pourront être ultérieurement exploités dans différentes applications dont l’authentification de documents imprimés. Une analyse de l’impression sur différents supports papier et par différentes imprimantes a été effectuée. Cette étude montre que la grande variété de forme dépend de la technologie et du papier. Le modèle proposé tient compte à la fois de la distribution du niveau de gris et de la répartition spatiale de l’encre sur le papier. Concernant le niveau de gris, les modèles des surfaces encrées/vierges sont obtenues en sélectionnant les distributions dans un ensemble de lois de forme similaire aux histogrammes et à l’aide de K-S critère. Le modèle de répartition spatiale de l’encre est binaire. Le premier modèle consiste en un champ de variables indépendantes de Bernoulli non-stationnaire dont les paramètres forment un noyau gaussien généralisé. Un second modèle de répartition spatiale des particules d’encre est proposé, il tient compte de la dépendance des pixels à l’aide d’un modèle de Markov non stationnaire. Deux méthodes d’estimation ont été développées, l’une approchant le maximum de vraisemblance par un algorithme de Quasi Newton, la seconde approchant le critère de l’erreur quadratique moyenne minimale par l’algorithme de Metropolis within Gibbs. Les performances des estimateurs sont évaluées et comparées sur des images simulées. La précision des modélisations est analysée sur des jeux d’images d’impression à l’échelle micrométrique obtenues par différentes imprimantes

Analysis and Simulation of MRC Diversity Reception in Correlated Composite Nakagami-Lognormal Fading Channels

The physical meaning of the composite Nakagami-lognormal fading model is not well understood by many researchers using the model. The signal power transfer and transform at the interface between the global lognormal shadowing sub-channels and the local Nakagami multipath sub-channels in the presence of correlation between these diversity sub-channels is rather complex. This is the main reason why a thorough analysis or a simulation model is absent to date for the case of correlated composite Nakagami-lognormal diversity channels. This paper presents a novel technique for the estimation of the probability density function (PDF) of the signal-to-noise (SNR) at the output of a maximum ratio combining (MRC) receiver operating in correlated composite diversity fading channels. The PDF is estimated using the recently proposed two-point lossless moment generating function (MGF) matching technique and a closed-form expression for the bit-error rate (BER) for QPSK signal is consequently presented using the Gauss-Hermite polynomial approximation. The paper also presents the complex Monte-Carlo simulation model for the MRC reception and BER counting in correlated composite Nakagami-lognormal fading channels

A data-driven approach for Network Intrusion Detection and Monitoring based on Kernel Null Space

International audienceIn this study, we propose a new approach to determine intrusions of network in real-time based on statistical process control technique and kernel null space method. The training samples in a class are mapped to a single point using the Kernel Null Foley-Sammon Transform. The Novelty Score are computed from testing samples in order to determine the threshold for the real-time detection of anomaly. The efficiency of the proposed method is illustrated over the KDD99 data set. The experimental results show that our new method outperforms the OCSVM and the original Kernel Null Space method by 1.53% and 3.86% respectively in terms of accuracy

DOLABRANE-TYPE DITERPENOID AND LIGNAN CONSTITUENTS FROM THE STEM BARKS OF CERIOPS DECANDRA (GRIFF.) W. THEOB.

Three dolabrane-type diterpenoids (1‒3) and a lignan derivative (4) were isolated from a methanolic extract of C. decandra stem barks using various chromatographic separations. Their structures were elucidated to be tagalsine X (1), tagalsin P (2), ent-5α,2-oxodolabr-3-ene-3,15,16-triol (3), and (+)-pinoresinol (4) by detailed analysis via spectroscopic techniques (1D, 2D NMR, and ESI-MS data) as well as comparison with those reported. This is the first report of compound 4 from the Ceriops genus

Analytical and numerical study of the apparent diffusion coefficient in diffusion MRI at long diffusion times and low b-values

Diffusion magnetic resonance imaging provides a measure of the average distance travelled by water molecules in a medium and can give useful information on cellular structure and structural change when the medium is biological tissue. In this paper, two approximate models for the apparent diffusion coefficient at low b-values and long diffusion times are formulated and validated. The first is a steady-state partial differential equation model that gives the steady-state (infinite time) effective diffusion tensor for general cellular geometries. For nearly isotropic diffusion where the intra-cellular compartment consists of non-elongated cells, a second approximate model is provided in the form of analytical formulae for the eigenvalue of the steady-state effective diffusion tensor. Both models are validated by numerical simulations on a variety of cells sizes and shapes

Impact of PLA/PEG ratios on Curcumin solubility and encapsulation efficiency, size and release behavior of Curcumin loaded poly(lactide)-poly(ethylenglycol) polymeric micelles

Curcumin, a natural compound isolated from rhizomes of the herb Curcuma longa, is suggested as a potential therapeutic agent thanks to its multiple biological and pharmaceutical activities including anti-inflammatory, anti-oxidant, wound healing, anti-microbial and anti-cancer activities. Particularly, Curcumin has demonstrated efficacy as an anticancer agent for various kinds of cancer. However, its low aqueous solubility and bioavailability hamper its clinical application. Therefore, many drug delivery systems have been developed to overcome these limitations. In this study, by using polymeric micelles composed by poly (lactide)-poly (ethylenglycol) (PLA-PEG) copolymers, the aqueous solubility of Curcumin was increased to 0.73 mg.mL-1 compared to 0.11×10-4 mg.mL-1 of pure Curcumin. In addition, we found that the ratio of PLA/PEG has large impact on Curcumin solubility, Curcumin encapsulation efficiency, size and Curcumin release behavior of polymeric micelles. The increase in Curcumin solubility, Curcumin encapsulation efficacy and particle size but decrease in Curcumin release rate were observed when increasing the PLA/PEG ratio

HOẠT HÓA THAN BÙN ĐỂ XỬ LÝ ION Cd2+ TRONG DUNG DỊCH NƯỚC

In this study, peat was activated with H3PO4 at a concentration of 2.0 M. The synthesized samples were characterized by several methods such as EDX, XRD, SEM, BET and FTIR. The adsorption properties of the materials were evaluated through their ability to remove Cd2+ ions in aqueous solution. Material characteristics show that the peat sample after activation has a higher specific surface area and porosity than the raw peat sample. The study shows that experimental data of Cd2+ ion adsorption on activated peat is well described simultaneously by both Langmuir and Freundlich isotherm models, however the Langmuir isotherm model appears to be more suitable. The activated peat material reached the maximum adsorption capacity qm 29.07 mg/g. In addition, the study also shows that the adsorption of Cd2+ ions on activated peat follows the apparent second-order kinetic model. From the above research results, it shows that adsorbent materials from peat have great potential in remove heavy metal ions in aqueous solution.Trong nghiên cứu này, vật liệu nghiên cứu là than bùn được hoạt hóa bằng H3PO4 ở nồng độ 2,0 M. Các mẫu sau khi tổng hợp được đặc trưng bởi một số phương pháp như EDX, XRD, SEM, BET và FTIR. Tính chất hấp phụ của vật liệu được đánh giá thông qua khả năng loại bỏ ion Cd2+ trong dung dịch nước. Đặc trưng vật liệu cho thấy mẫu than bùn sau khi hoạt hóa có diện tích bề mặt riêng và độ xốp cao hơn so với mẫu than bùn thô. Nghiên cứu cho thấy dữ liệu thực nghiệm hấp phụ ion Cd2+ trên than bùn được hoạt hóa được mô tả tốt đồng thời bởi cả hai mô hình đẳng nhiệt Langmuir và Freundlich, tuy nhiên mô hình đẳng nhiệt Langmuir tỏ ra phù hợp hơn. Vật liệu than bùn được hoạt hóa đạt dung lượng hấp phụ cực đại qm 29,07 mg/g. Ngoài ra nghiên cứu còn cho thấy sự hấp phụ ion Cd2+ trên than bùn hoạt hóa tuân theo mô hình động học biểu kiến bậc 2. Từ những kết quả nghiên cứu trên cho thấy vật liệu hấp phụ từ than bùn có nhiều tiềm năng trong việc loại bỏ các ion kim loại nặng trong dung dịch nước

New records of bats (Mammalia: Chiroptera) from Cu Lao Cham and Ly Son archipelagos, central Vietnam

Cu Lao Cham and Ly Son are two well-known archipelagos of Vietnam for their specular landscapes and varied ecosystems including forest, cave, and agriculture. However, their bat fauna has received little attention. Between July 2017 and August 2018, we conducted a series of mammal surveys with emphasis on bats of the two archipelagos. Bats were captured by mist nets and harp traps. Echolocation calls of microchiropteran species were recorded using the PCTape system then analysed by Selena software. With reference to all available literatures and specimens from the recent surveys, we obtained confirmed records of 9 bat species from Cu Lao Cham and 3 species from Ly Son. Of these, Megaderma spasma and Taphozous melanopogon are new to Cu Lao Cham while Rhinolophus macrotis is new to Ly Son. These three species were rarely recorded from other islands of Vietnam and also uncommon within Cu Lao Cham and Ly Son. These new records not only expand the known distributional range, but also provide worthwhile notes on a narrow geographical variation in morphology and echolocation of each species

Factors Influencing Cost Overruns in Construction Projects of International Contractors in Vietnam

A construction project is a designed product made up of labors, materials, and installations in the project positioned on the ground and may include the underground and ground section, and the section in water or on the water surface. It is a civil, industrial, transport, agricultural and rural development, infrastructure, or some other. A key phase in the life cycle of these construction projects is the implementation when building products are made directly with workers, equipment, materials, and managers. If there is a lack of management experience, information, and problem-solving solutions to tackle the risks faced by contractors, especially foreign ones, will fail in controlling the project’s cost. This study was conducted with investigations, discussions, and evaluation of the factors that lead to cost overruns in the construction projects of international contractors in Vietnam. The principal component analysis (PCA) showed that those factors that influence cost overruns these construction projects fall into five general groups, including factors related to (i) the owners, (ii) the foreign contractors, (iii) the subcontractors and suppliers, (iv) state management, and (v) the project itself. Besides, the study proposes solutions to limit cost overruns in construction projects and improve the profitability of international contractors in Vietnam

Multifunctional nanocarriers of Fe3O4@PLA-PEG/curcumin for MRI, magnetic hyperthermia and drug delivery

Background: Despite medicinal advances, cancer is still a big problem requiring better diagnostic and treatment tools. Magnetic nanoparticle (MNP)-based nanosystems for multiple-purpose applications were developed for these unmet needs. Methods: This study fabricated novel trifunctional MNPs of Fe3O4@PLA-PEG for drug release, MRI and magnetic fluid hyperthermia. Result: The MNPs provided a significant loading of curcumin (∼11%) with controllable release ability, a high specific absorption rate of 82.2 W/g and significantly increased transverse relaxivity (r2 = 364.75 mM-1 s-1). The in vivo study confirmed that the MNPs enhanced MRI contrast in tumor observation and low-field magnetic fluid hyperthermia could effectively reduce the tumor size in mice bearing sarcoma 180. Conclusion: The nanocarrier has potential for drug release, cancer treatment monitoring and therapy.The authors are grateful for the financial support by AOARD under award FA2386-17-1-4042. The Spanish government is acknowledged for the “Nanotechnology in translational hyperthermia (HIPERNANO)” research network (RED2018102626-T) and for funding under the project number MAT2017-83631-C3. NTK Thanh thanks EPSRC (EP/M015157/1). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed