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147 results on '"Ene, Cristian"'

1. Function synthesis for maximizing model counting

Author

Vigouroux, Thomas, Bozga, Marius, Ene, Cristian, and Mounier, Laurent

Subjects
Computer Science - Cryptography and Security, Computer Science - Logic in Computer Science
Abstract

Given a boolean formula $\Phi$(X, Y, Z), the Max\#SAT problem asks for finding a partial model on the set of variables X, maximizing its number of projected models over the set of variables Y. We investigate a strict generalization of Max\#SAT allowing dependencies for variables in X, effectively turning it into a synthesis problem. We show that this new problem, called DQMax\#SAT, subsumes both the DQBF and DSSAT problems. We provide a general resolution method, based on a reduction to Max\#SAT, together with two improvements for dealing with its inherent complexity. We further discuss a concrete application of DQMax\#SAT for symbolic synthesis of adaptive attackers in the field of program security. Finally, we report preliminary results obtained on the resolution of benchmark problems using a prototype DQMax\#SAT solver implementation.

Published
2023

2. BAXMC: a CEGAR approach to Max#SAT

Author

Vigouroux, Thomas, Ene, Cristian, Monniaux, David, Mounier, Laurent, and Potet, Marie-Laure

Subjects
Computer Science - Logic in Computer Science
Abstract

Max#SAT is an important problem with multiple applications in security and program synthesis that is proven hard to solve. It is defined as: given a parameterized quantifier-free propositional formula compute parameters such that the number of models of the formula is maximal. As an extension, the formula can include an existential prefix. We propose a CEGAR-based algorithm and refinements thereof, based on either exact or approximate model counting, and prove its correctness in both cases. Our experiments show that this algorithm has much better effective complexity than the state of the art., Comment: FMCAD 2022, Oct 2022, Trente, Italy

Published
2022
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3. Function Synthesis for Maximizing Model Counting

Author

Vigouroux, Thomas, Bozga, Marius, Ene, Cristian, Mounier, Laurent, Goos, Gerhard, Series Editor, Hartmanis, Juris, Founding Editor, van Leeuwen, Jan, Series Editor, Hutchison, David, Editorial Board Member, Kanade, Takeo, Editorial Board Member, Kittler, Josef, Editorial Board Member, Kleinberg, Jon M., Editorial Board Member, Kobsa, Alfred, Series Editor, Mattern, Friedemann, Editorial Board Member, Mitchell, John C., Editorial Board Member, Naor, Moni, Editorial Board Member, Nierstrasz, Oscar, Series Editor, Pandu Rangan, C., Editorial Board Member, Sudan, Madhu, Series Editor, Terzopoulos, Demetri, Editorial Board Member, Tygar, Doug, Editorial Board Member, Weikum, Gerhard, Series Editor, Vardi, Moshe Y, Series Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Dimitrova, Rayna, editor, Lahav, Ori, editor, and Wolff, Sebastian, editor

Published
2024
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5. Output-sensitive Information flow analysis

Author

Ene, Cristian, Mounier, Laurent, and Potet, Marie-Laure

Subjects
Computer Science - Cryptography and Security, Computer Science - Programming Languages
Abstract

Constant-time programming is a countermeasure to prevent cache based attacks where programs should not perform memory accesses that depend on secrets. In some cases this policy can be safely relaxed if one can prove that the program does not leak more information than the public outputs of the computation. We propose a novel approach for verifying constant-time programming based on a new information flow property, called output-sensitive noninterference. Noninterference states that a public observer cannot learn anything about the private data. Since real systems need to intentionally declassify some information, this property is too strong in practice. In order to take into account public outputs we proceed as follows: instead of using complex explicit declassification policies, we partition variables in three sets: input, output and leakage variables. Then, we propose a typing system to statically check that leakage variables do not leak more information about the secret inputs than the public normal output. The novelty of our approach is that we track the dependence of leakage variables with respect not only to the initial values of input variables (as in classical approaches for noninterference), but taking also into account the final values of output variables. We adapted this approach to LLVM IR and we developed a prototype to verify LLVM implementations.

Published
2019
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10. Gentzen-Prawitz Natural Deduction as a Teaching Tool

Author

Monin, Jean-François, Ene, Cristian, and Périn, Michaël

Subjects
Computer Science - Logic in Computer Science
Abstract

We report a four-years experiment in teaching reasoning to undergraduate students, ranging from weak to gifted, using Gentzen-Prawitz's style natural deduction. We argue that this pedagogical approach is a good alternative to the use of Boolean algebra for teaching reasoning, especially for computer scientists and formal methods practionners.

Published
2009

13. Stenotic ligature: a simple technique for managing distal hypoperfusion ischemic syndrome following arteriovenous fistulas

Author

Ene Cristian Roata, Corneliu Morosanu, Silviu-Tiberiu Makkai-Popa, Stefan Morarasu, Sorinel Lunca, and Gabriel Dimofte

Subjects
arteriovenous fistulas, stenotic ligature, distal hypoperfusion ischemic syndrome, Medicine
Abstract

Introduction. Distal Hypoperfusion Ischemic Syndrome (DHIS) is a multifactorial debilitating condition causing peripheral ischemia and potentially tissue necrosis. In an effort to further refine its surgical treatment we aim to describe a modified, simple and reliable technique for managing DHIS in patients with arteriovenous fistulas. Materials and Methods. Twenty-nine consecutive patients with DHIS operated by a single surgical team over a period of 7 years were included in the study. All patients underwent the same surgical technique: stenotic ligature. Outcomes were analyzed clinically and the effectiveness of the procedure was proven using McNemar test. Clinical variables were statistically analyzed in SPSS 17.0 for Windows. Results. The technique we used consists in performing a stenosing ligature on the vein, using a 0-silk suture, and adjusting the suture in order to achieve either a radial pulse or capillary pulse, while maintaining a good thrill at palpation of the vein. The procedure was successful in 83% of patients proved by immediate symptomatic relief. Paired data analysis showed significant decrease of all symptoms: cold extremity (p=0,021), paraesthesia (p

Published
2018
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17. CIL Security Proof for a Password-Based Key Exchange

Author

Ene, Cristian, Gritti, Clémentine, Lakhnech, Yassine, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Susilo, Willy, editor, and Reyhanitabar, Reza, editor

Published
2013
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18. On Unique Decomposition of Processes in the Applied π-Calculus

Author

Dreier, Jannik, Ene, Cristian, Lafourcade, Pascal, Lakhnech, Yassine, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, and Pfenning, Frank, editor

Published
2013
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19. Deciphering the role of water and a zinc-doping process in a polyol-based approach for obtaining Zn/Co/Al-based spinels: toward “green” mesoporous inorganic pigments

Author

Alexandru, Maria-Gabriela, primary, Ianculescu, Adelina-Carmen, additional, Carp, Oana, additional, Culita, Daniela C., additional, Preda, Silviu, additional, Ene, Cristian D., additional, Vasile, Bogdan Stefan, additional, Surdu, Vasile-Adrian, additional, Nicoara, Adrian-Ionut, additional, Neatu, Florentina, additional, Pintilie, Ioana, additional, and Visinescu, Diana, additional

Published
2023
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20. Automated Proofs for Asymmetric Encryption

Author

Courant, Joudicaël, Daubignard, Marion, Ene, Cristian, Lafourcade, Pascal, Lakhnech, Yassine, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Dams, Dennis, editor, Hannemann, Ulrich, editor, and Steffen, Martin, editor

Published
2010
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21. Formal Indistinguishability Extended to the Random Oracle Model

Author

Ene, Cristian, Lakhnech, Yassine, Ngo, Van Chan, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Backes, Michael, editor, and Ning, Peng, editor

Published
2009
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22. Computationally Sound Typing for Non-interference: The Case of Deterministic Encryption

Author

Courant, Judicaël, Ene, Cristian, Lakhnech, Yassine, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Arvind, V., editor, and Prasad, Sanjiva, editor

Published
2007
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24. A Symbolic Decision Procedure for Cryptographic Protocols with Time Stamps

Author

Bozga, Liana, Ene, Cristian, Lakhnech, Yassine, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Dough, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Gardner, Philippa, editor, and Yoshida, Nobuko, editor

Published
2004
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32. Nanocrystalline rhenium-doped TiO2: an efficient catalyst in the one-pot conversion of carbohydrates into levulinic acid. The synergistic effect between Brønsted and Lewis acid sites

Author

Avramescu, Sorin, primary, Ene, Cristian D., additional, Ciobanu, Madalina, additional, Schnee, Josefine, additional, Devred, Francois, additional, Bucur, Cristina, additional, Vasile, Eugeniu, additional, Colaciello, Luke, additional, Richards, Ryan, additional, Gaigneaux, Eric M., additional, and Verziu, Marian Nicolae, additional

Published
2022
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36. Nanocrystalline rhenium-doped TiO2: an efficient catalyst in the one-pot conversion of carbohydrates into levulinic acid. The synergistic effect between Brønsted and Lewis acid sites

Author

UCL - SST/IMCN/MOST - Molecular Chemistry, Materials and Catalysis, Avramescu, Sorin, Ene, Cristian D., Ciobanu, Madalina, Schnee, Josefine, Devred, François, Bucur, Cristina, Vasile, Eugeniu, Colaciello, Luke, Richards, Ryan, Gaigneaux, Eric M., Verziu, Marian Nicolae, UCL - SST/IMCN/MOST - Molecular Chemistry, Materials and Catalysis, Avramescu, Sorin, Ene, Cristian D., Ciobanu, Madalina, Schnee, Josefine, Devred, François, Bucur, Cristina, Vasile, Eugeniu, Colaciello, Luke, Richards, Ryan, Gaigneaux, Eric M., and Verziu, Marian Nicolae

Abstract

Catalytic activity of TiO2, 2%Re–TiO2 and 10%Re–TiO2 in the conversion of carbohydrates into levulinic acid under autoclave conditions was evaluated. These materials were prepared by aerogel method, for the first time to the best of our knowledge, and characterized by XPS, SEM-EDX, DRIFTS, DR UV-vis, Raman, N2 adsorption/desorption isotherms, TGA and XRD. Further, the surface acidity was probed by NH3-TPD and pyridine-FT-IR where it was observed that increasing the amount of rhenium doped into TiO2 led to an increase in the total number of acid sites (Lewis + Brønsted) but with an overall lower strength. The presence of both Brønsted and Lewis acid sites led to the hypothesis that these materials may be well suited for conversion of carbohydrates into levulinic acid. Indeed a levulinic acid yield of 57% was reached over 10%Re–TiO2 for a low mass ratio catalyst to glucose (1 : 5). Moreover, the 10%Re–TiO2 catalyst was reused in the conversion of glucose for four catalytic cycles without a significant loss of the catalytic activity.

Published
2021

37. Stenotic ligature: a simple technique for managing distal hypoperfusion ischemic syndrome following arteriovenous fistulas

Author

Stefan Morarasu, Silviu Tiberiu Makkai-Popa, G Dimofte, Sorinel Lunca, Ene Cristian Roata, and C Moroşanu

Subjects
medicine.medical_specialty, arteriovenous fistulas, business.industry, medicine.medical_treatment, lcsh:R, 030232 urology & nephrology, lcsh:Medicine, 030204 cardiovascular system & hematology, distal hypoperfusion ischemic syndrome, 03 medical and health sciences, 0302 clinical medicine, Internal medicine, Cardiology, Medicine, stenotic ligature, business, Ligature, Perfusion
Abstract

Introduction. Distal Hypoperfusion Ischemic Syndrome (DHIS) is a multifactorial debilitating condition causing peripheral ischemia and potentially tissue necrosis. In an effort to further refine its surgical treatment we aim to describe a modified, simple and reliable technique for managing DHIS in patients with arteriovenous fistulas. Materials and Methods. Twenty-nine consecutive patients with DHIS operated by a single surgical team over a period of 7 years were included in the study. All patients underwent the same surgical technique: stenotic ligature. Outcomes were analyzed clinically and the effectiveness of the procedure was proven using McNemar test. Clinical variables were statistically analyzed in SPSS 17.0 for Windows. Results. The technique we used consists in performing a stenosing ligature on the vein, using a 0-silk suture, and adjusting the suture in order to achieve either a radial pulse or capillary pulse, while maintaining a good thrill at palpation of the vein. The procedure was successful in 83% of patients proved by immediate symptomatic relief. Paired data analysis showed significant decrease of all symptoms: cold extremity (p=0,021), paraesthesia (p less 0,001), pain (p less 0,001). History of coronary artery disease, arteriopathy or the absence of radial pulse is statistically correlated with an increased risk of developing DHIS. Conclusions. Stenotic ligature is a simple, cheap and reliable technique for managing DHIS with lower septic risks which can be easily performed under local anesthesia.

Published
2018

49. Comparison Between Alprostadil and Iloprost in Intravenous Treatment of Patients With Chronic Peripheral Arterial Disease

Author

Dan Nicolae, Tesloianu, Corneliu, Morosanu, Ene-Cristian, Roata, and Laurentiu, Sorodoc

Subjects
Original Paper
Abstract

chronic peripheral arterial disease (PAD) seems to be a "rediscovered" pathology nowadays, brought into spotlight by its strong correlation with other signifi cant cardiovascular disorders.to sustain a real benefi t from treatment with i.v. prostaglandins (PG) in PAD patients and to directly compare the currently used PG: alprostadil and iloprost.open, non-randomized cohort study, with placebo group ("classical therapy") reviewing 615 PAD patients with therapeutic approach during 2003-2012 period, divided in 3 subgroups: "classical" therapy; "classical" therapy + iloprost; "classical" therapy + alprostadil; patients with Burger's disease were excluded; multiple factor analysis with statistical results inserted.clear domination of male gender patients, with older female gender patients (p.0.001); smoking like major risk factor in male and in all patients (p0.0001); 124 patients underwent angiography .a real improvement in the clinical status of patients receiving i.v. prostaglandin therapy with no diff erences between genders, diabetic and non-diabetic patients; alprostadil seems better than iloprost.

Published
2017

50. OUTPUT-SENSITIVE INFORMATION FLOW ANALYSIS.

Author

ENE, CRISTIAN, MOUNIER, LAURENT, and POTET, MARIE-LAURE

Subjects
GOVERNMENT accounting, CACHE memory, LEAKAGE
Abstract

Constant-time programming is a countermeasure to prevent cache based attacks where programs should not perform memory accesses that depend on secrets. In some cases this policy can be safely relaxed if one can prove that the program does not leak more information than the public outputs of the computation. We propose a novel approach for verifying constant-time programming based on a new information flow property, called output-sensitive noninterference. Noninterference states that a public observer cannot learn anything about the private data. Since real systems need to intentionally declassify some information, this property is too strong in practice. In order to take into account public outputs we proceed as follows: instead of using complex explicit declassification policies, we partition variables in three sets: input, output and leakage variables. Then, we propose a typing system to statically check that leakage variables do not leak more information about the secret inputs than the public normal output. The novelty of our approach is that we track the dependence of leakage variables with respect not only to the initial values of input variables (as in classical approaches for noninterference), but taking also into account the final values of output variables. We adapted this approach to LLVM IR and we developed a prototype to verify LLVM implementations. [ABSTRACT FROM AUTHOR]

Published
2021
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