Sed‐Dedup: An efficient secure deduplication system with data modifications

2019 ◽  
pp. e5350
Author(s):  
Wenlong Tian ◽  
Ruixuan Li ◽  
Cheng‐Zhong Xu ◽  
Zhiyong Xu
Keyword(s):  
Data Modifications

scholarly journals Time intervals in sequence sampling, not data modifications, have a major impact on estimates of HIV escape rates

2017 ◽  
Author(s):  
Vitaly V. Ganusov
Keyword(s):  
T Cell ◽  
Chronic Infection ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Escape Rate ◽  
Viral Escape ◽  
Time Interval ◽  
Acute Hiv Infection ◽  
Cell Responses ◽  
Data Modifications

AbstractThe ability of HIV to avoid recognition by humoral and cellular immunity (viral escape) is well documented but the strength of the immune response needed to cause such a viral escape remains poorly quantified. Several previous studies observed a more rapid escape of HIV from CD8 T cell responses in the acute phase of infection as compared to the chronic infection. With the help of simple mathematical models the rate of HIV escape was estimated and results were interpreted to suggest that CD8 T cell responses causing escape in acute HIV infection may be more efficient at killing virus-infected cells than responses that cause escape in chronic infection, or alternatively, early escapes occur in epitopes mutations in which there is minimal fitness cost to the virus. These conclusions, however, were challenged on several grounds, including linkage and interference of multiple escape mutations due to a low population size and because of potential issues associated with modifying the data to estimate escape rates. Here we use a parametric resampling method which does not require data modification to show that previous results on the decline of the viral escape rate with time since infection remain unchanged. However, using this method we also show that estimates of the escape rate are highly sensitive to the time interval between measurements with longer intervals biasing estimates of the escape rate downwards. Our results thus suggest that data modifications for early and late escapes were not the primary reason for the observed decline in the escape rate with time since infection. However, longer sampling periods for escapes in chronic infection strongly influence estimates of the escape rate. More frequent sampling of viral sequences in the chronic infection may improve our understanding of factors influencing the rate of HIV escape from CD8 T cell responses.

scholarly journals A Fragile Zero Watermarking Scheme to Detect and Characterize Malicious Modifications in Database Relations

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Aihab Khan ◽  
Syed Afaq Husain
Keyword(s):  
Data Quality ◽  
Relational Database ◽  
Relational Databases ◽  
Original Data ◽  
Experimental Results ◽  
Zero Watermarking ◽  
Watermarking Scheme ◽  
Database Relation ◽  
Data Usability ◽  
Data Modifications

We put forward a fragile zero watermarking scheme to detect and characterize malicious modifications made to a database relation. Most of the existing watermarking schemes for relational databases introduce intentional errors or permanent distortions as marks into the database original content. These distortions inevitably degrade the data quality and data usability as the integrity of a relational database is violated. Moreover, these fragile schemes can detect malicious data modifications but do not characterize the tempering attack, that is, the nature of tempering. The proposed fragile scheme is based on zero watermarking approach to detect malicious modifications made to a database relation. In zero watermarking, the watermark is generated (constructed) from the contents of the original data rather than introduction of permanent distortions as marks into the data. As a result, the proposed scheme is distortion-free; thus, it also resolves the inherent conflict between security and imperceptibility. The proposed scheme also characterizes the malicious data modifications to quantify the nature of tempering attacks. Experimental results show that even minor malicious modifications made to a database relation can be detected and characterized successfully.

ADAPTIVE QUERY OPTIMIZATION IN DYNAMIC DATABASES

1998 ◽  
Vol 07 (01) ◽  
pp. 1-30
Author(s):  
MIN J. YU ◽  
P. C-Y. SHEU
Keyword(s):  
Query Optimization ◽  
Optimization Algorithm ◽  
Optimal Solution ◽  
Complex Objects ◽  
Access Path ◽  
Dynamic Databases ◽  
Partial Plan ◽  
Data Modifications

This paper addresses the problem of query optimization for databases in which objects frequently change their values. A greedy, adaptive query optimization algorithm is proposed to evaluate relational queries and queries containing complex objects. Rather than contructing a full plan for an access path and executing it, the algorithm constructs a partial plan, executes it, updates the statistics, and constructs a new partial plan. Since a partial plan is constructed based on the latest statistics, the algorithm is adaptive to data modifications and errors from the statistics. It is proved that the algorithm can produce an optimal solution for a class of queries. Furthermore, experiments show that the overhead associated with the algorithm is negligible and the algorithm is efficient for other cases.

A NEW CLASSIFICATION OF THE BRACONIDAE (HYMENOPTERA) BASED ON THE CEPHALIC STRUCTURES OF THE FINAL INSTAR LARVA AND BIOLOGICAL EVIDENCE

1970 ◽  
Vol 102 (7) ◽  
pp. 846-875 ◽  
Author(s):  
M. Čapek
Keyword(s):  
Instar Larva ◽  
Biological Data ◽  
New Classification ◽  
Biological Evidence ◽  
Higher Categories ◽  
Data Modifications

AbstractThe cephalic structures of the final instar larva of 278 species of 140 genera of Braconidae were examined. On the basis of these and biological data, modifications are proposed in the classification of the higher categories. Zele (Helconinae) and Eubadizon (Blacinae) are placed in the Macrocentrinae (endoparasites of larval Lepidoptera) and Meteoridea is moved from the Helconinae and ranked as an independent subfamily. The Blacinae is completely dismembered: Aliolus, Triaspis, Urosigalphus, Blacus, and Calyptus form a tribe of the Helconinae (endoparasites of larval Coleoptera); Microtypus, Orgilus, and Stantonia form a tribe of the Agathidinae (endoparasites of larval Lepidoptera); and Pygostolus, Centistes, and Syrrhizus a subfamily near Euphorinae with Cosmophorus (endoparasites of adult Coleoptera). Present genera of Microgasterinae are separated into two tribes with the addition of the Cardiochilini as a third tribe. The Dacnusinae is reduced to a tribe of the Alysiinae. The Rogadinae is reduced to one tribe, Rogadini, containing only Rogas and allied genera (endoparasites of larval Lepidoptera). Rhyssalus is transferred to the Hecabolini, and Exothecini, Pambolini, Hormiini, and ectoparasitic Rogadini to the Braconinae (ectoparasites of larval Coleoptera, Lepidoptera, etc.). The problematic genus Gnaptodon is also placed in the Braconinae.

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