113 research outputs found
Gaining deep knowledge of Android malware families through dimensionality reduction techniques
[Abstract] This research proposes the analysis and subsequent characterisation of Android malware families by means of low dimensional visualisations using dimensional reduction techniques. The well-known Malgenome data set, coming from the Android Malware Genome Project, has been thoroughly analysed through the following six dimensionality reduction techniques: Principal Component Analysis, Maximum Likelihood Hebbian Learning, Cooperative Maximum Likelihood Hebbian Learning, Curvilinear Component Analysis, Isomap and Self Organizing Map. Results obtained enable a clear visual analysis of the structure of this high-dimensionality data set, letting us gain deep knowledge about the nature of such Android malware families. Interesting conclusions are obtained from the real-life data set under analysis
Gaining deep knowledge of Android malware families through dimensionality reduction techniques
This research proposes the analysis and subsequent characterisation of Android malware families by means of low
dimensional visualisations using dimensional reduction techniques. The well-known Malgenome data set, coming from
the Android Malware Genome Project, has been thoroughly analysed through the following six dimensionality reduction
techniques: Principal Component Analysis, Maximum Likelihood Hebbian Learning, Cooperative Maximum Likelihood
Hebbian Learning, Curvilinear Component Analysis, Isomap and Self Organizing Map. Results obtained enable a clear visual
analysis of the structure of this high-dimensionality data set, letting us gain deep knowledge about the nature of such Android
malware families. Interesting conclusions are obtained from the real-life data set under analysis
Delving into Android Malware Families with a Novel Neural Projection Method
[Abstract] Present research proposes the application of unsupervised and supervised machine-learning techniques to characterize Android malware families. More precisely, a novel unsupervised neural-projection method for dimensionality-reduction, namely, Beta Hebbian Learning (BHL), is applied to visually analyze such malware. Additionally, well-known supervised Decision Trees (DTs) are also applied for the first time in order to improve characterization of such families and compare the original features that are identified as the most important ones. The proposed techniques are validated when facing real-life Android malware data by means of the well-known and publicly available Malgenome dataset. Obtained results support the proposed approach, confirming the validity of BHL and DTs to gain deep knowledge on Android malwar
Resonance frequency analysis-reliability in third generation instruments : Osstell mentor ®
Few studies assess repeatability and reproducibility in registers of resonance frequency analysis (a value of dental implant stability). Objective: Few studies assess repeatability and reproducibility in resonance frequency analyses (implant stability evaluation). This study is aimed at assessing reliability (repeatabilty and reproducibility) in the Osstell Mentor® system using the intraclass correlation coefficient (ICC) as the statistical method. Study Design: ISQ measurements of RFA were carried out by means of the Osstell Mentor ® instrument in 58 implants in 19 patients. Six measurements were performed on each implant by means of two different Smart-Pegs (I and II). Three consecutive measurements were registered with each transducer. Results: Average ISQ varied from 72.43 to 72.60 and 73.26 in the first, second and third measurements, respectively with the SamrtPeg I and from 72.98 to 73.26 and 73.74 in the first, second and third measurements, respectively with the SamrtPeg II . Exactly equal values were observed in 10.43 and 12.1% of the cases with Smart-Pegs I and II, respectively. The intraclass correlation coefficient was 0.96 and 0.96 for Smart Pegs I and II, respectively. Repeatability and reproducibility was 0.97 for both Smart-Pegs I and II. Conclusions: The RFA system contributed by Osstell Mentor ® renders almost perfect reproducibility and repeatability, as proven by statistical analysis carried out by means of ICC with 95% confidence level. This instrument contributes highly reliable RFA measurements in dental implants
Delving into Android Malware Families with a Novel Neural Projection Method
Present research proposes the application of unsupervised and supervised machine-learning techniques to characterize Android malware families. More precisely, a novel unsupervised neural-projection method for dimensionality-reduction, namely, Beta Hebbian Learning (BHL), is applied to visually analyze such malware. Additionally, well-known supervised Decision Trees (DTs) are also applied for the first time in order to improve characterization of such families and compare the original features that are identified as the most important ones. The proposed techniques are validated when facing real-life Android malware data by means of the well-known and publicly available Malgenome dataset. Obtained results support the proposed approach, confirming the validity of BHL and DTs to gain deep knowledge on Android malware.This work is partially supported by Instituto Nacional de Ciberseguridad (INCIBE) and developed by Research Institute of Applied Sciences in Cybersecurity (RIASC)
A non-interventional Study documenting use and success of tissue level implants
Numerous randomised controlled multicentric studies have investigated various responses to different treatment modalities with dental implants. These studies do not always show the results of daily practice as they are performed under controlled and strict clinical conditions. This multicentric, non-interventionist trial aimed to document the behaviour of implants when used in daily dental practice, without inclusion or exclusion criteria. One hundred and ninety-six screw-shaped, tissue-level implants were placed, and each clinician decided which implant, surgical loading and prosthetic protocol to use. At surgery, data related to the implants were recorded. Additionally, the crestal bone level changes were evaluated for up to two years of follow-up.
Two implants were lost before they were loaded. The success rate was 98.31%, and the survival rate was 98.79%. The implant stability quotient (ISQ) at surgery was 68.61 ± 10.35 and at 2 years was 74.39 ± 9.64. The crestal–shoulder distances were 1.25 ± 1.09 mm and 1.68 ± 1.07 mm in the mesial and distal aspects on the day of surgery, respectively, and 2.04 ± 0.91 and 2.16 ± 0.99 mm at 2 years, respectively. At 2 years, 69.3% of the patients were highly satisfied. The use of implants under standard conditions seemed to have success rates similar to their placement in controlled studies
Advances in surfaces and osseointegration in implantology. Biomimetic surfaces
The present work is a revision of the processes occurring in osseointegration of titanium dental implants according
to different types of surfaces -namely, polished surfaces, rough surfaces obtained from subtraction methods, as
well as the new hydroxyapatite biomimetic surfaces obtained from thermochemical processes. Hydroxyapatite’s
high plasma-projection temperatures have proven to prevent the formation of crystalline apatite on the titanium
dental implant, but lead to the formation of amorphous calcium phosphate (i.e., with no crystal structure) instead.
This layer produce some osseointegration yet the calcium phosphate layer will eventually dissolve and leave a gap
between the bone and the dental implant, thus leading to osseointegration failure due to bacterial colonization.
A new surface -recently obtained by thermochemical processes- produces, by crystallization, a layer of apatite
with the same mineral content as human bone that is chemically bonded to the titanium surface. Osseointegration
speed was tested by means of minipigs, showing bone formation after 3 to 4 weeks, with the security that a dental
implant can be loaded. This surface can be an excellent candidate for immediate or early loading procedure
Rigid polyurethane foams with infused nanoclays: Relationship between cellular structure and thermal conductivity
Producción CientíficaA water blown rigid polyurethane (PU) formulation has been used to manufacture cellular
nanocomposites containing different concentrations of montmorillonite nanoclays. The PU
foams have been produced using a low shear mixing technique for dispersing the nanoclays
and by reactive foaming to generate the cellular structure. A detailed characterization
of the cellular structure has been performed. The effect of the nanoparticles on the
reaction kinetics and the state of intercalation of the nanoparticles in the foams has been
analyzed. The thermal conductivity and extinction coefficient of the different materials has
been measured and the results obtained have been correlated with the materials structure.
A strong reduction of cell size and modifications on cell size distribution, anisotropy ratio
and fraction of material in the struts has been detected when the clays are added. In addition,
a reduction of the thermal conductivity has been observed. Different theoretical models
have been employed to explain thermal conductivity changes in terms of structural
features. It has been found that, in addition to the modifications in the cellular structure,
changes in the extinction coefficient and thermal conductivity of the matrix polymer play
an important role on the final values of the thermal conductivity for these materials.We would like to acknowledge to Mr. Vela and Mr. Ferrer, from BASF Española S.L., for supplying the PU formulation employed in this research. The authors are grateful to the Spanish Ministry of Science and Education which supported this work with a FPU Grant Ref-AP-2008-03602 given to Mr. Estravís. In addition, Financial assistance from the Spanish Ministry of Science and Innovation, FEDER program (MAT 2012 – 34901 and MAT2015-69234-R), the Junta de Castile and Leon (VA035U13) and the EU Commission (FP7 program, EC project NanCore number 214148) is acknowledged
Spanish study of anticoagulation in haemodialysis
This study's objectives were to determine which anticoagulation
methods are commonly used in patients who are undergoing haemodialysis (HD) in
Spain, on what criteria do they depend, and the consequences arising from their
use. MATERIAL AND METHOD: Ours was a cross-sectional study based on two types of
surveys: a "HD Centre Survey" and a "Patient Survey". The first survey was
answered by 87 adult HD units serving a total of 6093 patients, as well as 2
paediatric units. Among these units, 48.3% were part of the public health system
and the remaining 51.7% units were part of the private health system. The patient
survey analysed 758 patients who were chosen at random from among the
aforementioned 78 HD units. RESULTs: A) HD Centre Survey: The majority of adult
HD units (n=61, 70.2%) used both kinds of heparin, 19 of them (21.8%) only used
LMWH and 7 of them (8%) only used UFH. The most frequently applied criteria for
the use of LMWH were medical indications (83.3% of HD units) and ease of
administration (29.5%). The most frequently used methods for adjusting the dosage
were clotting of the circuit (88.2% of units), bleeding of the vascular access
after disconnection (75.3%), and patient weight (57.6%). B) Patient Survey: The
distribution of the types of heparin used was: UFH: 44.1%, LMWH: 51.5%, and
dialysis without heparin in 4.4% of patients. LMWH was more frequently used in
public medical centres (64.2% of patients) than in private medical centres
(46.1%) (P<.001). LMWH was more frequently used in on-line haemodiafiltration
(HF) than in high-flux HD (P<.001). Antiplatelet agents were given to 45.5% of
patients, oral anticoagulants to 18.4% of patients, and both to 5% of patients.
Additionally, 4.4% of patients had suffered bleeding complications during the
previous week, and 1.9% of patients suffered thrombotic complications. Bleeding
complications were more frequent in patients with oral anticoagulants (P=.001),
although there was no association between the type of heparin and the occurrence
of bleeding or thrombotic complications. CONCLUSIONS: We are able to conclude
that there is a great amount of disparity in the criteria used for the medical
prescription of anticoagulation in HD. It is advisable that each HD unit revise
their own results as well as those from other centres, and possibly to create an
Anticoagulation Guide in Haemodialysis
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