187,828 research outputs found
A large study on the effect of code obfuscation on the quality of java code
No full textContext: Obfuscation is a common technique used to protect software against malicious reverse engineering. Obfuscators manipulate the source code to make it harder to analyze and more difficult to understand for the attacker. Although different obfuscation algorithms and implementations are available, they have never been directly compared in a large scale study.
Aim: This paper aims at evaluating and quantifying the effect of several different obfuscation implementations (both open source and commercial), to help developers and project managers to decide which algorithms to use.
Method: In this study we applied 44 obfuscations to 18 subject applications covering a total of 4 millions lines of code. The effectiveness of these source code obfuscations has been measured using 10 code metrics, considering modularity, size and complexity of code.
Results: Results show that some of the considered obfuscations are effective in making code metrics change substantially from original to obfuscated code, although this change (called potency of the obfuscation) is different on different metrics. In the paper we recommend which obfuscations to select, given the security requirements of the software to be protected
Code Defactoring: Evaluating the Effectiveness of Java Obfuscations
No full textObfuscation is a very common protection against
reverse engineering attacks: it modifies a program structure to
make it harder for the adversary to analyse and understand
it. Conceptually, obfuscation is the opposite of refactoring: the
code should be more complex to understand, bloated, and with
excessive characteristics from the design point of view.
This paper aims at evaluating the code complexity introduced
by different obfuscation algorithms by using software
engineering metrics. Using structural metrics, this paper illustrates
how the various types of obfuscation algorithms perform
in terms of OO attributes that should be kept low in refactoring.
Results show that the majority of the selected algorithms
produce no changes in the structural attributes or the average
complexity, but they produce more “dead” code. We argue
that this could not represent the optimal way to protect the
code: when protecting against reverse engineering attacks, a
preference should be given to those algorithms that increase
the complexity and alter the structural metrics
MALATTIA DI HUNTINGTON AD ESORDIO TARDIVO:ENTITA¿ CLINICA DISTINTA?
No full textIntroduction: Huntington’s disease (HD) is an autosomal dominant neurodegenerative disorder caused by a CAG expansion in the HTT gene and characterized by motor symptoms (chorea), cognitive impairment and psychiatric manifestations. It usually has onset in adult life between the ages of 30 and 50, and leads to death within 17-20 years. When onset falls outside the usual age spectrum, diagnosis may be more challenging and prognosis may be different. The term ‘late-onset HD’, encompassed in earlier papers all cases with symptoms onset above age 60. There are few reports that have focused specifically on late-onset HD. They have concluded that motor problems are predominant, cognitive decline is mild, psychiatric manifestations are rare, and that disease progression is slower. However, these were purely observational studies in which no comparisons were made with classic-onset HD. Since the characterization of HD is important, mainly in the view of the risk for offspring, also in the case of late onset, we analysed the spectrum of clinical, cognitive and behavioural features in HD patients subdivided according to the age at onset, as specified below.
Methods: from 2004 to 2015 we analyzed clinical, cognitive and behavioural characteristics (UHDRS I,II,III scale) of a cohort of 66 patients with HD at the diagnosis (T0) and at the follow up (T1) and with a CAG expansion between 40 and 42. We divided patients on the base of onset disease:
- 37 patients with classic onset (CO) ≤59 years: 17 F and 20 M. 6 patients with 40 CAG, 10 patients with 41 CAG, 21 patients with 42 CAG. 33 patients had a positive family history for HD (13 maternal history, 20 paternal history). 32 patients had a 1-2 stage of disease, 5 patients had a 3-4 stage of disease.
- 29 patients with late onset (LO) ≥ 60 years: 18 F and 11 M. 11 patients with 40 CAG, 10 patients with 41 CAG, 8 patients with 42 CAG. 20 patients had a positive family history for HD (9 maternal history, 11 paternal history). 22 patients had a 1-2 stage of disease, 7 patients had a 3-4 stage of disease.
The age at onset was defined as the age at which the first motor symptoms became clearly manifest.
We investigated behavioural, cognitive or mood disorders (depression) associated to motor symptoms at the disease’s onset and we divided onset symptoms in: motor (M), motor + behavioural (M/P), motor + cognitive (M/C) or motor + behavioural + cognitive (M/C/P). 25 CO patients had only M onset, 12 M+ (1 patient M/C, 8 patients M/P, 3 M/P/C); 22 LO patients had only M onset, 7 M+ (2 patient M/C, 5 patients M/P).
Statistic: The data were analyzed using chi-square, Fisher’s test, T-test, Pearson’s correlation coefficient as appropriate. Kaplan Meier analysis was used to assess disease progression.
Results: a statistically significant difference was observed in absence of family history in LO group (P 0.0403). No differences were observed in type of transmission. Frequencies of onset symptoms (M,M/P,M/C,M/C/P), stage at the diagnosis and mood disorder (depression) before motor onset were not significantly different in two groups. A significant inverse correlation between CAG repeat size and age at onset was observed only for the upper allele (P 0.0403). No significant differences were found in clinical, behavioral, cognitive (UHDRS I,II,III) characteristics, TFC and FA between two groups at the diagnosis (T0) and at the FU (T1). No difference in disease progression was found in two groups.
Discussion: A positive family history suggestive of HD, remains a helpful clue in diagnosing classic-onset HD. Previous studies on late-onset HD have suggested that motor disturbance (chorea) is the predominant early manifestation of late onset. In our cohort no clinical differences at diagnosis were observed in two groups. Similarly, the frequency of cognitive impairment and psychiatric manifestations at onset or at presentation was equivalent in late-onset and classic-onset HD patients. Previous reports have concluded that late-onset HD is relatively mild with slower progression compared to mid-life onset HD. To this regard, our findings in fact suggest that in terms of Total Functional Capacity, functional assessment and stage of disease, prognosis of late-onset HD is by no means better or more mildly progressing compared to classic onset HD.
Conclusion: our findings confirm that there are no clinical, cognitive, and psychiatric differences at diagnosis and at FU in two groups of patients. The prognosis of late-onset HD is not better compared to CO. Age of onset is only “better” of late onset
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
CMS The Computing Project: Technical Design Report
No full textThis document provides a top-level description of the organisation of the CMS Offline Computing systems
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