58 research outputs found
Graph Encryption for Shortest Path Queries with k Unsorted Nodes
No full textShortest distance queries over large-scale graphs bring great benefits to various applications, i.e., save planning time and travelling expenses. To protect the sensitive nodes and edges in the graph, a user outsources an encrypted graph to an untrusted server without losing the query ability. However, no prior work has considered the user requirement of the shortest path with k unsorted nodes. In particular, we are concerned with how to securely find the shortest path by passing k nodes that do not have a fixed traverse order. To solve the problems, we propose Gespun (stands for Graph encryption for shortest path queries with k unordered nodes). It includes an oracle encryption scheme that is provably secure against the semi-honest server. Specifically, we compute the shortest paths and distances for all nodes locally to obtain path-distance oracles. We transform the shortest paths to a sequence of secure codes by using a pseudo-random permutation to protect the structure privacy. We encrypt the shortest distance by using additively homomorphic encryption. Second, we pack the oracles in link-list nodes and store them in an array-based dictionary after another permutation. Next, we construct a search graph to compute the shortest path while guaranteeing that the path passes the required k nodes. We formally prove that Gespun is adaptively semanticallysecure in the random oracle. We implement a prototype of Gespun and evaluate its performance. Experiments results demonstrate that Gespun is efficient, e.g., a query over 6301 nodes, 20777 edges, and 5 unsorted nodes only needs 483 ms to get queried results. We believe that our research problem span new research that soon promotes a new line of graph encryption schemes
Graph Encryption for Shortest Path Queries with k Unsorted Nodes
No full textShortest distance queries over large-scale graphs bring great benefits to various applications, i.e., save planning time and travelling expenses. To protect the sensitive nodes and edges in the graph, a user outsources an encrypted graph to an untrusted server without losing the query ability. However, no prior work has considered the user requirement of the shortest path with k unsorted nodes. In particular, we are concerned with how to securely find the shortest path by passing k nodes that do not have a fixed traverse order. To solve the problems, we propose Gespun (stands for Graph encryption for shortest path queries with k unordered nodes). It includes an oracle encryption scheme that is provably secure against the semi-honest server. Specifically, we compute the shortest paths and distances for all nodes locally to obtain path-distance oracles. We transform the shortest paths to a sequence of secure codes by using a pseudo-random permutation to protect the structure privacy. We encrypt the shortest distance by using additively homomorphic encryption. Second, we pack the oracles in link-list nodes and store them in an array-based dictionary after another permutation. Next, we construct a search graph to compute the shortest path while guaranteeing that the path passes the required k nodes. We formally prove that Gespun is adaptively semantically-secure in the random oracle. We implement a prototype of Gespun and evaluate its performance. Experiments results demonstrate that Gespun is efficient, e.g., a query over 6301 nodes, 20777 edges, and 5 unsorted nodes only needs 483 ms to get queried results. We believe that our research problem span new research that soon promotes a new line of graph encryption schemes.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Cyber Securit
Corrigendum: The impact of population influx on infectious diseases – from the mediating effect of polluted air transmission
No full textOne-pot synthesis of dextran-coated iron oxide nanoclusters for real-time regional lymph node mapping
No full textChaoping Fu,1,* Haipeng Zhou,2,* Yanan Wang,2,* Dong Liu,2 Junmeng Li,2 Haijun Deng,2 Xiaolong Qi,2 Tao Chen,2 Li-Ming Zhang,1 Guoxin Li2 1PCFM Lab and GDHPPC Lab, School of Materials Science and Engineering, Sun Yat-sen University, 2Department of General Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, People’s Republic of China *These authors contributed equally to this work Abstract: The intraoperative precision cleaning of lymph nodes (LNs) is an essential component of treating neoplastic disease. To develop efficient probes for the targeted detection of LNs that could act as carriers for the specific diagnosis and treatment of metastatic LNs in the future, dextran-coated iron oxide nanoclusters (DIONs) were synthesized using a one-pot coprecipitation procedure. These modified DIONs have good water dispersibility, cytocompatibility, an optimum size, and a stable, dark brown color for LN imaging. In this study, cytotoxicity was evaluated using lymphatic endothelial cells (LECs) to predict biosafety and biocompatibility. Most importantly, the effectiveness of DIONs in mapping perigastric LNs in Sprague Dawley rats following injection into the gastric submucosal layer was demonstrated. In addition, a long-term tracing in vivo (from 4 days to 3 months) indicated that the DIONs had good biosafety and biocompatibility according to an evaluation of the behavior and blood biochemistry of the rat and a histopathological examination of the important organs. Keywords: dextran-coated iron oxide nanoclusters, lymph node mapping, biosafety, lymphatic endothelial cell
Constructions of Nonbinary Codes Correcting t-Symmetric Errors and Detecting All Unidirectional Errors: Magnitude Error Criterion
No full textOptimal rate list decoding of folded algebraic-geometric codes over constant-sized alphabets
No full textWe construct a new list-decodable family of asymptotically good algebraic-geometric (AG) codes over fixed alphabets. The function fields underlying these codes are constructed using class field theory, specifically Drinfeld modules of rank 1, and designed to have an automorphism of large order that is used to “fold” the AG code. This generalizes earlier work by the first author on folded AG codes based on cyclotomic function fields. The recent linear-algebraic approach to list decoding can be applied to our new codes, and crucially, we use the Chebotarev density theorem to establish a polynomial upper bound on the list-size for list decoding up to an error fraction approaching 1 – R where R is the rate. The list decoding can be performed in polynomial time given polynomial amount of pre-processed information about the function field.Our construction yields algebraic codes over constant-sized alphabets that can be list decoded up to the Singleton bound — specifically, for any desired rate R ∊ (0, 1) and constant ∊ > 0, we get codes over an alphabet size that can be list decoded up to error fraction 1 – R – ∊ confining close-by messages to a subspace with elements. Previous results for list decoding up to error-fraction 1 – R – ∊ over constant-sized alphabets were either based on concatenation or involved taking a carefully chosen subcode of algebraic-geometric codes. In contrast, our result shows that these folded algebraic-geometric codes themselves have the claimed list decoding property. Further, our methods to get function fields with the properties needed for constructing and decoding the code might be of independent algebraic interest.Published versio
Beating the probabilistic lower bound on -perfect hashing
No full textFor an integer , a perfect -hash code is a block code over
of length in which every subset
of elements is
separated, i.e., there exists such that
,
where denotes the th position of
. Finding the maximum size of perfect -hash codes of
length , for given and , is a fundamental problem in combinatorics,
information theory, and computer science. In this paper, we are interested in
asymptotic behavior of this problem. Precisely speaking, we will focus on the
quantity .
A well-known probabilistic argument shows an existence lower bound on ,
namely \cite{FK,K86}.
This is still the best-known lower bound till now except for the case
\cite{KM}. The improved lower bound of was discovered in 1988 and there
has been no progress on the lower bound of for more than years. In
this paper we show that this probabilistic lower bound can be improved for
from to and all odd integers between and , and \emph{all
sufficiently large} .Comment: arXiv admin note: text overlap with arXiv:1010.5764 by other author
Experiment and verification of fine gridded precipitation forecast fusion correction in Sichuan
No full textFine-scale quantitative precipitation forecast is a key issue and challenge in weather forecasting services. In this study, based on hourly precipitation from the 1 km× 1 km resolution Southwest China WRF-based Intelligent Numeric Grid forecast System (SWC-WINGS), a fusion-corrected experiment was conducted using time lag and probability matching methods. The fusion-corrected forecast of hourly pre⁃ cipitation was then verified utilizing the CMA Multi-source Precipitation Analysis System (CMAPS) three-source merged precipitation obser⁃ vation grid data from 1 July to 31 August 2022 in Sichuan. Finally, the fusion-corrected method was applied to a short-term heavy precipita⁃ tion process over the western Sichuan Basin. The results show that: (1) Compared with the model precipitation forecasts, the time-lagged en⁃ semble forecast was over-optimistic for small-scale precipitation and over-conservative for large-scale precipitation. (2) However, the fu⁃ sion-corrected method by time lag and probability matching methods overcame the above difficulties and showed significant improvement in the TS score, particularly in 1~2 h nowcast time. The TS score for hourly precipitation exceeding 0.1 mm, 5 mm, 10 mm, and 20 mm were in⁃ creased on average by 7.2%, 17.2%, 28.3%, and 36.3%, respectively. (3) A case studies also showed that the fusion-corrected method had good improvement and correction capabilities on the hourly precipitation forecast, especially for large-scale precipitation forecasts
The Research on Exogenous Problems of Farmers’ Piritual and Cultural Education in China
No full textThe author studied and analyzed the exogenous problems of the farmers’ spiritual and cultural education, and found out: In today’s China, the exogenous problems of the farmers’ spiritual and cultural education mainly reflected in the separation of spiritual and cultural education is from social environment, political system, economic development, and cultural concepts etc. Then the author put forward to the countermeasures and suggestions aimed at optimizing the allocation of famers’ spiritual and cultural educations resources, environment and evaluation system construction and so on
- …
