Papers by Anh Kiệt Nguyễn
The Environmental and Health Impacts of Chemical Spraying: Can Law Protect Victims? The Case of Agent Orange
Environmental Health in International and EU Law, 2019
info:eu-repo/semantics/submittedForPublicatio
Thermo-chemo-mechanical Modelling of Refractory Behaviour
International audienc
The aim of this work is to develop a new numerical method to overcome the computational difficult... more The aim of this work is to develop a new numerical method to overcome the computational difficulties of numerical simulation of unsaturated impregnation in porous media. The numerical analysis by classical methods (F.E.M, theta-method, …) for this phenomenon require small time-step and space discretization to ensure both convergence and accuracy. Yet this leads to a high computational cost. Moreover, a very small time-step can lead to spurious oscillations that impact the precision of the results. Thus, we propose to use a Self-organized Gradient Percolation (SGP) algorithm to reduce the computational cost and overcome these numerical drawbacks. The (SGP) method is based on gradient percolation theory, relevant to calculation of local saturation. The initialization of this algorithm is driven by an analytic solution of the homogenous diffusion equation, which is a convolution between a Probability Density Function (PDF) and a smoothing function. Thus, we propose to reproduce the evo...
Journal of Multilingual and Multicultural Development, 2020
SEG Technical Program Expanded Abstracts 2016, 2016
Electromagnetic signals are exponentially attenuated in conductive media. Thus, marine controlled... more Electromagnetic signals are exponentially attenuated in conductive media. Thus, marine controlled-source electromagnetic (CSEM) data where the source and the receivers are located in the water column has exponentially low sensitivity towards the deep stratigraphy, compared to the shallow stratigraphy. In addition, CSEM inversions are also highly non-linear and ill-posed. It is therefore often difficult to achieve good inversion results for the deeper part of the subsurface using gradient based inversion methods. In this abstract, we describe a large-scale 3-dimensional anisotropic Gauss-Newton (3DGN) CSEM inversion implementation and discuss its advantages over gradient based algorithms. We also show, by synthetic and real data case studies, the large improvements in the 3DGN inversion results compared to those from the Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm.
Safe Transportation Research Education Center, 2007
The focus of this study is to quantify the sufficiency of "Flashing Don't Walk" (FDW) intervals a... more The focus of this study is to quantify the sufficiency of "Flashing Don't Walk" (FDW) intervals at signalized pedestrian crossings in the San Pablo Avenue (SPA) corridor in Northern California. Our goal is to determine if pedestrian signal intervals on the SPA corridor can be optimized in a way that makes the pedestrian crossing environment safer and more comfortable for all pedestrians without diminishing vehicular throughput. This study provides a corridor-wide as well as a city-by-city assessment of FDW intervals on the SPA corridor. We suggest a possible tool to assist traffic control jurisdictions in prioritizing intersections that may require adjustments of timing to pedestrian signals. The findings provide the agencies participating in the "SMART" corridor program a means to evaluate an aspect of pedestrian safety and comfort that has likely been adversely affected by placing a high priority on vehicular traffic through the corridor, without sufficiently considering pedestrian traffic.
Inversion of inline and broadside marine controlled‐source electromagnetic data with constraints derived from seismic data
Geophysical Prospecting, 2015
ABSTRACTWe present a structural smoothing regularization scheme in the context of inversion of ma... more ABSTRACTWe present a structural smoothing regularization scheme in the context of inversion of marine controlled‐source electromagnetic data. The regularizing hypothesis is that the electrical parameters have a structure similar to that of the elastic parameters observed from seismic data. The regularization is split into three steps. First, we ensure that our inversion grid conforms with the geometry derived from seismic. Second, we use a seismic stratigraphic attribute to define a spatially varying regularization strength. Third, we use an indexing strategy on the inversion grid to define smoothing along the seismic geometry. Enforcing such regularization in the inversion will encourage an inversion result that is more intuitive for the interpreter to deal with. However, the interpreter should also be aware of the bias introduced by using seismic data for regularization. We illustrate the method using one synthetic example and one field data example. The results show how the regul...
International journal of environmental research and public health, Jan 8, 2015
With the rapid development of the waste incineration industry in China, top priority has been giv... more With the rapid development of the waste incineration industry in China, top priority has been given to the problem of pollution caused by waste incineration. This study is the first attempt to assess all the waste incineration plants in Wuhan, the only national key city in central China, in terms of environmental impact, site selection, public health and public participation. By using a multi-criterion assessment model for economic, social, public health and environmental effects, this study indicates these incineration plants are established without much consideration of the local residents' health and environment. A location analysis is also applied and some influences of waste incineration plants are illustrated. This study further introduces a signaling game model to prove that public participation is a necessary condition for improving the environmental impact assessment and increasing total welfare of different interest groups in China. This study finally offers some corre...
Lecture Notes in Computer Science, 2012
In this paper, two stream ciphers, SOBER-t32 and SNOW 2.0 are used to generate sequences of pseud... more In this paper, two stream ciphers, SOBER-t32 and SNOW 2.0 are used to generate sequences of pseudo random numbers. The original S-Boxes of these ciphers are replaced by Skipjack, IRSC, AES-Rijndael S-Box, and variants of AES-Rijndael S-Boxes. Pseudo-random sequences generated by SOBER-t32 and SNOW 2.0 using these S-Boxes are then tested by statistical test suite and analyzed by linear distinguishing cryptanalysis for randomness properties. The results show that these S-Boxes do not have much contribution to the statistical randomness of the pseudo-sequences but play significant roles on the nonlinearity of the ciphers. Hence, affect the randomness of sequences in cryptanalysis aspect.
2009 Annual Computer Security Applications Conference, 2009
Malicious software is rampant on the Internet and costs billions of dollars each year. Safe and t... more Malicious software is rampant on the Internet and costs billions of dollars each year. Safe and thorough analysis of malware is key to protecting vulnerable systems and cleaning those that have already been infected. Most current state-of-the-art analysis platforms run alongside the malware, increasing their detectability. This reduces the value of analysis because some malware is known to behave differently when being analyzed. Virtualization offers a compelling platform for malware analysis, with strong isolation and the ability to save and restore guest state. Current virtual machine monitors (VMMs), however, are not designed for malware analysis. Due to their complexity, they often fail to provide transparency and even expose vulnerabilities which could be exploited by the malware running inside guest system. We propose a lightweight VMM (namely MAVMM) that is designed specially for a single job: malware analysis. MAVMM does not implement unnecessary virtualization features commonly found in general purpose hypervisors, including virtual device emulation. We take advantage of hardware virtualization support to make MAVMM more simple, secure and transparent. In this paper, we describe the design and implementation of MAVMM, and the features that we can extract from programs running inside the guest OS. We evaluate our platform in three aspects: functionality, detectability and performance. We show that our system can extract useful information from malicious software, and that it is not susceptible to known virtualization detection techniques.
Natural Language Interface Construction Using Semantic Grammars
Lecture Notes in Computer Science, 2008
This paper is a study on constructing a natural language interface to relational databases, which... more This paper is a study on constructing a natural language interface to relational databases, which accepts natural language questions as inputs and generates textual responses. The question is translated into a SQL query using a semantic grammar and then, a database management system is left to find the result table with its own specialized optimization and planning techniques. The textual
Mining interprocedural, data-oriented usage patterns in JavaScript web applications
Proceedings of the 36th International Conference on Software Engineering, 2014
ABSTRACT
SPIE Newsroom, 2013
An automatic feedback tool offers a natural, informative way to support presentation skills train... more An automatic feedback tool offers a natural, informative way to support presentation skills training by analyzing the nonverbal expressions of speakers.
SSRN Electronic Journal, 2013
Upon examining the language used in recent SEC filings, we find that severance agreements are oft... more Upon examining the language used in recent SEC filings, we find that severance agreements are often paid whether or not the CEO leaves the firm due to a change in control. We hypothesize that since severance agreements compensate CEOs in the event of termination, CEOs with these agreements will have an incentive to increase firm risk and decrease effort. Consistent with this hypothesis, we find that the adoption of a severance agreement is associated with an increase in firm risk, a higher likelihood of CEO turnover, and a lower operating performance. We also document a significant positive relation between the use of severance agreements and the cost of debt; firms in which the CEO has a severance agreement have yield spreads which are approximately 10% higher than firms without these agreements. The results hold after controlling for endogeneity, the probability of takeover, and whether the firm has investment or noninvestment grade debt. Overall, the evidence suggests that the effects of severance agreements extend beyond takeovers, and that these additional implications are primarily negative for the firm and for debt holders in particular.
Kidney International, 1996
Advanced oxidation protein products as a novel marker of oxidative stress in uremia. Evidence sug... more Advanced oxidation protein products as a novel marker of oxidative stress in uremia. Evidence suggests an imbalance between antioxidant and oxidant-generating systems resulting in oxidative stress in uremic patients. As plasma proteins are critical targets for oxidants, we developed a novel spectrophotometric assay which allows to detect advanced oxidation protein products (AOPP) in uremic plasma. By size-exclusion chromatography AOPP are retrieved in two distinct peaks at 600 and below 80 kDa in ureniic plasma, while no such peaks are found in control plasma. Further biochemical characterization revealed that AOPP are carried by oxidized plasma proteins, especially albumin and do not have oxidant properties. AOPP increased in a dose-dependent manner following in vitro exposure of plasma or purified human serum albumin (HSA) to hypochlorous acid. Advanced glycation end products of human serum albumin (AGE-HSA) also increased AOPP levels. In vivo, plasma level of AOPP was the highest in patients on hemodialysis, followed by those on peritoneal dialysis and by undialyzed patients with advanced chronic renal failure. AOPP levels correlated with plasma concentrations of dityrosine and AGE-pentosidine, as indices of oxidant-mediated protein damage, but not with thiobarbituric reactive substances as lipid peroxidation markers. A close correlation was also found between AOPP and neopterin levels, suggesting that AOPP could be part in the monocyte-mediated inflammatory disorders associated with uremia. In conclusion, we propose the measurement of AOPP as a reliable marker to estimate the degree of oxidant-mediated protein damage in uremic patients and to predict the potential efficacy of therapeutic strategies aimed at reducing such an oxidative stress. Chronic renal failure (CRF) is associated with a multifactorial immuno-inflammatory syndrome that occurs early in the course of renal failure, worsens with its progression and culminates on maintenance dialysis therapy, as recently reviewed in [1]. Among the mechanisms involved in such uremia-related immuno-inflamamyloidosis observed in dialysis patients [26, 27]. In this study we describe and characterize a novel oxidative stress marker referred to as advanced oxidation protein products (AOPP), which are present at high levels in the plasma of uremic patients. Methods
Journal of Lipid Research, 2002
LDL from human apolipoprotein B-100 (apoB-100) transgenic (HuBTg ؉ / ؉) mice contains more trigly... more LDL from human apolipoprotein B-100 (apoB-100) transgenic (HuBTg ؉ / ؉) mice contains more triglyceride than LDL from normolipidemic subjects. To obtain novel monoclonal antibody (MAb) probes of apoB conformation, we generated hybridomas from HuBTg ؉ / ؉ that had been immunized with LDL isolated from human plasma. One apoE-specific and four anti-apoB-100-specific hybridomas were identified. Two MAbs, 2E1 and 3D11, recognized an epitope in the amino-terminal 689 residues of apoB in native apoB-containing lipoproteins (LpBs) from human plasma or from the supernatant of human hepatoma HepG2 cells, but did not react with LpB from HuBTg ؉ / ؉ mice or LpB secreted by human apoB-100-transfected rat McArdle 7777 hepatoma cells. 2E1 reacted weakly and 3D11 reacted strongly with apoB from HuBTg ؉ / ؉ mice after SDS-PAGE. The lack of expression of the 2E1 and 3D11 epitopes on native LpB from HuBTg ؉ / ؉ mice did not solely reflect the abnormal lipid composition of murine LpB. Both epitopes were detected in all human plasma samples tested and in all human plasma LpB classes. Therefore, human apoB expressed by rodent hepatocytes or hepatoma cells appears to adopt a different conformation or undergoes different posttranslational modification than apoB expressed in human hepatocytes or hepatoma cells.
The Journal of Chemical Physics, 2014
We develop a method that combines data mining and first principles calculation to guide the desig... more We develop a method that combines data mining and first principles calculation to guide the designing of distorted cubane Mn4 +\documentclass[12pt]{minimal}\begin{document}${\rm Mn}^{3+}_3$\end{document} Mn 33+ single molecule magnets. The essential idea of the method is a process consisting of sparse regressions and cross-validation for analyzing calculated data of the materials. The method allows us to demonstrate that the exchange coupling between Mn4 + and Mn3 + ions can be predicted from the electronegativities of constituent ligands and the structural features of the molecule by a linear regression model with high accuracy. The relations between the structural features and magnetic properties of the materials are quantitatively and consistently evaluated and presented by a graph. We also discuss the properties of the materials and guide the material design basing on the obtained results.
International Journal of Mineral Processing, 2013
The current modeling flotation approach of the Julius Kruttschnitt Mineral Research Centre (JKMRC... more The current modeling flotation approach of the Julius Kruttschnitt Mineral Research Centre (JKMRC) predicts recoveries in a flotation circuit using a lumped parameter called the floatability of mineral particles (P) which has no direct physical meaning and is assumed to be conserved in flotation circuits in the absence of regrinding or change in chemical environment. In this paper, the original definition of P as the efficiency of collection was resurrected. Fundamental models of particle collection by bubbles were applied to an industrial data set from a down-the-bank flotation survey of the first four cells of the galena rougher circuit at BHP Billiton's Cannington operation in Australia. The floatability of mineral particles P was no longer treated as a lumped parameter but described by the physical measurable inputs of the models. Induction time as a model parameter was back-calculated from knowledge of the experimental data and application of the collection model. The assumption that the induction time of a size-by-liberation class at fixed chemistry was conserved allowed prediction of galena recoveries in the circuit. An extensive error analysis was conducted on the new modeling approach and it was found to be very sensitive to the value of the bubble rise velocity. Finally, since the variation in the key flotation variables down the bank at the BHP Billiton Cannington's lead rougher circuit was not significant, the two approaches predicted similar flotation kinetics down the bank.
Glutathione antioxidant system as a marker of oxidative stress in chronic renal failure
Free Radical Biology and Medicine, 1996
A profound imbalance between oxidants and antioxidants has been suggested in uremic patients on m... more A profound imbalance between oxidants and antioxidants has been suggested in uremic patients on maintenance hemodialysis. However, the respective influence of uremia and dialysis procedure has not been evaluated. Circulating levels of copper-zinc superoxide dismutase (CuZn SOD), glutathione peroxidase (GSH-Px), and reductase (GSSG-Rd), total GSH and GSSG were determined in a large cohort of 233 uremic patients including 185 undialyzed patients with mild to severe chronic renal failure, and 48 patients treated by peritoneal dialysis or hemodialysis. Compared to controls, erythrocyte GSH-Px and GSSG-Rd activities were significantly increased at the mild stage of chronic uremia (p < .001), whereas erythrocyte CuZn SOD activity was unchanged, total level of GSH and plasma GSH-Px activity were significantly decreased, and GSSG level and GSSG-Rd activity were unchanged. Positive Spearman rank correlations were observed between creatinine clearance and plasma levels of GSH-Px (r = .65, p < .001), selenium (r = .47, p < .001), and GSH (r = .41, p < .001). Alterations in antioxidant systems gradually increased with the degree of renal failure, further rose in patients on peritoneal dialysis and culminated in hemodialysis patients in whom an almost complete abolishment of GSH-Px activity was observed. In conclusion, such disturbances in antioxidant systems that occur from the early stage of chronic uremia and are exacerbated by dialysis provide additional evidence for a resulting oxidative stress that could contribute to the development of accelerated atherosclerosis and other long-term complications in uremic patients.
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Papers by Anh Kiệt Nguyễn