3,464 research outputs found
Analysis of plasma-nitrided steels
The analysis of plasma nitrided steels can be divided to two main categories - structural and chemical. Structural analysis can provide information not only on the hardening mechanisms but also on the fundamental processes involved. Chemical analysis can be used to study the kinetics for the nitriding process and its mechanisms. In this paper preliminary results obtained by several techniques of both categories are presented and the applicability of those techniques to the analysis of plasma-nitrided steels is discussed
Theory of x-ray absorption by laser-dressed atoms
An ab initio theory is devised for the x-ray photoabsorption cross section of
atoms in the field of a moderately intense optical laser (800nm, 10^13 W/cm^2).
The laser dresses the core-excited atomic states, which introduces a dependence
of the cross section on the angle between the polarization vectors of the two
linearly polarized radiation sources. We use the Hartree-Fock-Slater
approximation to describe the atomic many-particle problem in conjunction with
a nonrelativistic quantum-electrodynamic approach to treat the photon-electron
interaction. The continuum wave functions of ejected electrons are treated with
a complex absorbing potential that is derived from smooth exterior complex
scaling. The solution to the two-color (x-ray plus laser) problem is discussed
in terms of a direct diagonalization of the complex symmetric matrix
representation of the Hamiltonian. Alternative treatments with time-independent
and time-dependent non-Hermitian perturbation theories are presented that
exploit the weak interaction strength between x rays and atoms. We apply the
theory to study the photoabsorption cross section of krypton atoms near the K
edge. A pronounced modification of the cross section is found in the presence
of the optical laser.Comment: 13 pages, 3 figures, 1 table, RevTeX4, corrected typoe
Engineering a static verification tool for GPU kernels
We report on practical experiences over the last 2.5 years related to the engineering of GPUVerify, a static verification tool for OpenCL and CUDA GPU kernels, plotting the progress of GPUVerify from a prototype to a fully functional and relatively efficient analysis tool. Our hope is that this experience report will serve the verification community by helping to inform future tooling efforts. © 2014 Springer International Publishing
On the Feasibility of Malware Authorship Attribution
There are many occasions in which the security community is interested to
discover the authorship of malware binaries, either for digital forensics
analysis of malware corpora or for thwarting live threats of malware invasion.
Such a discovery of authorship might be possible due to stylistic features
inherent to software codes written by human programmers. Existing studies of
authorship attribution of general purpose software mainly focus on source code,
which is typically based on the style of programs and environment. However,
those features critically depend on the availability of the program source
code, which is usually not the case when dealing with malware binaries. Such
program binaries often do not retain many semantic or stylistic features due to
the compilation process. Therefore, authorship attribution in the domain of
malware binaries based on features and styles that will survive the compilation
process is challenging. This paper provides the state of the art in this
literature. Further, we analyze the features involved in those techniques. By
using a case study, we identify features that can survive the compilation
process. Finally, we analyze existing works on binary authorship attribution
and study their applicability to real malware binaries.Comment: FPS 201
Stiction, Adhesion Energy and the Casimir Effect in Micromechanical Systems
We measure the adhesion energy of gold using a micromachined doubly-clamped
beam. The stress and stiffness of the beam are characterized by measuring the
spectrum of mechanical vibrations and the deflection due to an external force.
To determine the adhesion energy we induce stiction between the beam and a
nearby surface by capillary forces. Subsequent analysis yields a value J/m that is a factor of approximately six smaller than predicted
by idealized theory. This discrepancy may be resolved with revised models that
include surface roughness and the effect of adsorbed monolayers intervening
between the contacting surfaces in these mesoscopic structures.Comment: RevTex, 4 pages, 4 eps figure
Aboriginal life pathways through multiple human service domains; administrative data linkage for policy
Aboriginal children and families face the highest levels of disadvantage of any population group in Australia across health, education, child protection, justice and other human service domains, but longitudinal data to inform policy is scant. The Western Australian Aboriginal Child Health Survey (WAACHS) is a population representative cross-sectional child development study of over 5,000 randomly selected children aged 0-17 years, plus their families and schools, conducted between 2000 and 2002. This project seeks to leverage the WAACHS by linking the survey data for all participants with State administrative human services data registers from the previous 30+ years, to develop a major program of work in Aboriginal Human Development that would be unique in the world. This presentation describes the project history, novel survey linkage methodology, and project aims in the policy domain
Ambiguous figures and the content of experience
Representationalism is the position that the phenomenal character of an experience is either identical with, or supervenes on, the content of that experience. Many representationalists hold that the relevant content of experience is nonconceptual. I propose a counterexample to this form of representationalism that arises from the phenomenon of Gestalt switching, which occurs when viewing ambiguous figures. First, I argue that one does not need to appeal to the conceptual content of experience or to judgements to account for Gestalt switching. I then argue that experiences of certain ambiguous figures are problematic because they have different phenomenal characters but that no difference in the nonconceptual content of these experiences can be identified. I consider three solutions to this problem that have been proposed by both philosophers and psychologists and conclude that none can account for all the ambiguous figures that pose the problem. I conclude that the onus is on representationalists to specify the relevant difference in content or to abandon their position
Enhanced inverse bremsstrahlung heating rates in a strong laser field
Test particle studies of electron scattering on ions, in an oscillatory
electromagnetic field have shown that standard theoretical assumptions of small
angle collisions and phase independent orbits are incorrect for electron
trajectories with drift velocities smaller than quiver velocity amplitude. This
leads to significant enhancement of the electron energy gain and the inverse
bremsstrahlung heating rate in strong laser fields. Nonlinear processes such as
Coulomb focusing and correlated collisions of electrons being brought back to
the same ion by the oscillatory field are responsible for large angle, head-on
scattering processes. The statistical importance of these trajectories has been
examined for mono-energetic beam-like, Maxwellian and highly anisotropic
electron distribution functions. A new scaling of the inverse bremsstrahlung
heating rate with drift velocity and laser intensity is discussed.Comment: 12 pages, 12 figure
Lung cancer surgery in octogenarians: a meta-analysis of predictors for postoperative complications
Background: Recently, several reports had focused on the feasibility of lung cancer surgery in octogenarians,
describing encouraging short and long-term survival. However, the postoperative complication rate remains
high. Some papers analyzed the role of potential predictors of post-operative complications, showing
discordant results. We aimed at systematically assessing the evidence on risk factors for post-operative
complications in octogenarians undergoing lung cancer surgery.
Methods: Literature search was performed through PubMed and MEDLINE using the terms âlung
cancerâ, ânon-small cell lung cancerâ or âlung cancer surgeryâ combined with âoctogenarianâ or â80 yearsâ.
Last search was performed on 03/2021. Inclusion criteria were: clinical studies involving octogenarians
undergoing lung cancer surgery between 1990 and 2020; studies explicitly appraising risk factors for postoperative
complications and providing adjusted risk effect estimates. Studies that did not explicitly investigate
predictors of postoperative complications and papers published in other language than English were not
included. Risk of bias was assessed using the Quality in Prognostic Factor Studies (QUIPS) tool. More than
20 potential predictors were screened, finally limiting the inferential analysis to the six most frequently
reported: performance status (PS), forced expiratory volume in 1 second (FEV1), type of resection, surgical
approach, history of tobacco abuse and male gender. Adjusted P values from individual studies were pooled
with the Fisher method. A pooled 2-tailed P value â€0.05 was considered statistically significant.
Results: A final set of 13 cohort studies, including 2,596 patients, was considered. Effect estimates were
reported for PS by 6 studies (46%), for FEV1 by 10 (77%), for type of resection by 11 (85%), for surgical
approach by 4 (31%), for history of tobacco abuse by 6 (46%), and for male gender by 8 (62%). After
inferential analysis with the Fisher method, a significant association with post-operative complications was
found for PS (P=0.004), major resections (P=0.002) and open approach (P=0.007); male gender showed only
a borderline trend (P=0.053). Preoperative FEV1 (P=0.109) and history of tobacco abuse (P=0.399) were not
associated with increased postoperative complications.
Conclusions: Lung cancer surgery in octogenarian patients represent a viable and useful treatment.
According to our analysis, patients should be carefully selected considering that a good preoperative PS is
associated with a lower rate of postoperative complications. Similarly, thoracoscopic approach and sublobar
resection should be preferred in octogenarian patients if technically and oncologically sound. Interestingly,
impaired lung function was not significantly associated to post-operative complications
System dependence graphs in sequential Erlang
The system dependence graph (SDG) is a data structure used in the imperative paradigm for different static analysis, and particularly, for program slicing. Program slicing allows us to determine the part of a program (called slice) that influences a given variable of interest. Thanks to the SDG, we can produce precise slices for interprocedural programs. Unfortunately, the SDG cannot be used in the functional paradigm due to important features that are not considered in this formalism (e.g., pattern matching, higher-order, composite expressions, etc.). In this work we propose the first adaptation of the SDG to a functional language facing these problems. We take Erlang as the host language and we adapt the algorithms used to slice the SDG to produce precise slices of Erlang interprocedural programs. As a proof-of-concept, we have implemented a program slicer for Erlang based on our SDGs.This work has been partially supported by the Spanish Ministerio de Ciencia e
InnovaciÂŽon under grant TIN2008-06622-C03-02 and by the Generalitat Valenciana
under grant PROMETEO/2011/052. Salvador Tamarit was partially supported by
the Spanish MICINN under FPI grant BES-2009-015019Silva Galiana, JF.; Tamarit Muñoz, S.; TomĂĄs Franco, C. (2012). System dependence graphs in sequential Erlang. En Fundamental Approaches to Software Engineering. Springer Verlag (Germany). 486-500. https://doi.org/10.1007/978-3-642-28872-2_33S486500Agrawal, H., Horgan, J.R.: Dynamic program slicing. In: Programming Language Design and Implementation (PLDI), pp. 246â256 (1990)Brown, C.: Tool Support for Refactoring Haskell Programs. PhD thesis, School of Computing, University of Kent, Canterbury, Kent, UK (2008)Cheda, D., Silva, J., Vidal, G.: Static slicing of rewrite systems. Electron. Notes Theor. Comput. Sci. 177, 123â136 (2007)Ferrante, J., Ottenstein, K.J., Warren, J.D.: The Program Dependence Graph and Its Use in Optimization. ACM Transactions on Programming Languages and Systems 9(3), 319â349 (1987)Field, J., Ramalingam, G., Tip, F.: Parametric program slicing. In: Proceedings of the 22nd ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages, POPL 1995, pp. 379â392. ACM, New York (1995)Horwitz, S., Reps, T., Binkley, D.: Interprocedural slicing using dependence graphs. ACM Transactions Programming Languages and Systems 12(1), 26â60 (1990)Korel, B., Laski, J.: Dynamic Program Slicing. Information Processing Letters 29(3), 155â163 (1988)Larsen, L., Harrold, M.J.: Slicing object-oriented software. In: Proceedings of the 18th International Conference on Software Engineering, ICSE 1996, pp. 495â505. IEEE Computer Society, Washington, DC (1996)Liang, D., Harrold, M.J.: Slicing objects using system dependence graphs. In: Proceedings of the International Conference on Software Maintenance, ICSM 1998, pp. 358â367. IEEE Computer Society, Washington, DC (1998)Lindahl, T., Sagonas, K.F.: Typer: a type annotator of erlang code. In: Sagonas, K.F., Armstrong, J. (eds.) Erlang Workshop, pp. 17â25. ACM (2005)Lindahl, T., Sagonas, K.F.: Practical type inference based on success typings. In: Bossi, A., Maher, M.J. (eds.) PPDP, pp. 167â178. ACM (2006)Ochoa, C., Silva, J., Vidal, G.: Dynamic slicing based on redex trails. In: Proceedings of the 2004 ACM SIGPLAN Symposium on Partial Evaluation and Semantics-Based Program Manipulation, PEPM 2004, pp. 123â134. ACM, New York (2004)Reps, T., Turnidge, T.: Program Specialization via Program Slicing. In: Danvy, O., Thiemann, P., GlĂŒck, R. (eds.) Dagstuhl Seminar 1996. LNCS, vol. 1110, pp. 409â429. Springer, Heidelberg (1996)Rodrigues, N.F., Barbosa, L.S.: Component identification through program slicing. In: Proc. of Formal Aspects of Component Software (FACS 2005). Elsevier ENTCS, pp. 291â304. Elsevier (2005)Tip, F.: A survey of program slicing techniques. Journal of Programming Languages 3(3), 121â189 (1995)TĂłth, M., BozĂł, I., HorvĂĄth, Z., Lövei, L., Tejfel, M., Kozsik, T.: Impact Analysis of Erlang Programs Using Behaviour Dependency Graphs. In: HorvĂĄth, Z., Plasmeijer, R., ZsĂłk, V. (eds.) CEFP 2009. LNCS, vol. 6299, pp. 372â390. Springer, Heidelberg (2010)Walkinshaw, N., Roper, M., Wood, M., Roper, N.W.M.: The java system dependence graph. In: Third IEEE International Workshop on Source Code Analysis and Manipulation, p. 5 (2003)Weiser, M.: Program Slicing. In: Proceedings of the 5th International Conference on Software Engineering, pp. 439â449. IEEE Press (1981)Widera, M.: Flow graphs for testing sequential erlang programs. In: Proceedings of the 2004 ACM SIGPLAN Workshop on Erlang, ERLANG 2004, pp. 48â53. ACM, New York (2004)Widera, M., Informatik, F.: Concurrent erlang flow graphs. In: Proceedings of the Erlang/OTP User Conference (2005)Zhao, J.: Slicing aspect-oriented software. In: Proceedings of the 10th International Workshop on Program Comprehension, IWPC 2002, pp. 251â260. IEEE Computer Society, Washington, DC (2002
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