Existing Keyword Search Research Articles

Verifiable attribute-based multi-keyword search scheme with sensitive information hiding for cloud-assisted e-healthcare sharing systems

Cloud-assisted e-healthcare sharing systems (EHSSs) play an increasingly pivotal role in the contemporary healthcare field. By outsourcing electronic medical records (EMRs) to the cloud, hospitals can alleviate local storage and management burdens while facilitating data sharing. Due to the highly sensitive nature of EMRs, encryption is necessary before storing them on the cloud. Attribute-based keyword search (ABKS) enables the privacy protection of EMRs with efficient search services. However, there remain some limitations in practical application. Firstly, most ABKS schemes only support single keyword queries, resulting in inaccurate results and wastage of computing and bandwidth resources. Secondly, since sensitive information within EMRs is encrypted as a whole, different data users (including internal doctors and external researchers) should have varying access rights to prevent leakage of this sensitive information. Thirdly, incorrect search results could lead to misdiagnosis or endanger patients' lives and affect researchers' decision-making processes. To effectively tackle these challenges, this paper proposes a verifiable attribute-based multi-keyword search scheme with sensitive information hiding (VABMKS-SIH) for cloud-assisted EHSSs, where we present a secure model for multi-keyword search with two-level access structure by incorporating an improved blindness filtering technique into ciphertext-policy attribute-based encryption (CP-ABE) within existing keyword search framework. Our scheme employs a super-increasing sequence to aggregate multiple filtered data blocks into one unified ciphertext, thereby greatly reducing communication overhead during the transmission phases of ciphertext. To check the correctness of returned results, we introduce a lightweight algebraic signature algorithm based on fundamental algebraic operations. A security analysis demonstrates that VABMKS-SIH is provably secure under the random oracle mode. Additionally, we also evaluate the proposed scheme's performance to demonstrate its utility in cloud-assisted EHSSs.

Optimizing Keyword Search Over Federated RDF Systems

The issue of keyword search in federated resource description framework(RDF) systems is revisited in this paper. Numerous independent SPARQL endpoints that solely offer SPARQL query interfaces make up a federated RDF system. Others find it challenging to remotely build up the global inverted indices over the full RDF network by downloading the dataset at various SPARQL endpoints. This poses a challenge for existing keyword search approaches. In this paper, we propose a keyword search approach for federated RDF systems without building up global inverted indices on the entire RDF graph. We build an offline schema graph for the federated RDF system. During query evaluation, the full-text search interfaces provided by existing SPARQL endpoints were used to map keywords to vertices in the schema graph. Subsequently, the schema graph was explored to construct SPARQL queries from the keywords. The constructed queries were evaluated over the underlying federated RDF systems. Some cost models were proposed to measure keyword mapping and query construction. On the other hand, to further improve the efficiency, a multiple query optimization strategy was designed to rewrite the queries and share the common computation during evaluation. Extensive experiments on real RDF datasets show that the proposed techniques are effective.

A Novel Fuzzy Logic-Based Text Classification Method for Tracking Rare Events on Twitter

A rare event, such as a natural disaster, does not occur frequently, but may cause catastrophic impacts on human beings and their living environment once it happens. Social media provides people an immediate and convenient way to share their opinions. Researchers can thus use it for investigating people's actions, feelings, and attitudes during multiple rare events. By using social media data, many studies try to build the connection between rare events in a real world and people's responses, including feelings, attitudes, and behaviors, in a virtual world. In this article, we propose a feature extraction and text classification approach to Twitter text data related to a rare event, e.g., Hurricane Sandy. First, a novel feature extraction method is proposed to mine useful features from each text message. Next, a fuzzy logic-based classification method is proposed to distinguish event-related and unrelated messages. Finally, our proposed method is compared with the existing keyword search one that is widely used in analyzing the evolution of a rare event. The result reveals that the proposed approach is suitable to identify the rare event-related and unrelated text messages.

Secure and Verifiable Keyword Search in Multiple Clouds

Searchable encryption enables users to perform a keyword-based search over encrypted data. Most of the existing searchable encryption schemes are based on the single cloud server model, which has some limitations, such as the single point of failure and malicious insiders. In contrast, the multicloud server model has higher data availability and security. However, directly moving the existing keyword search schemes to the multicloud would cause larger storage and search costs, and the data security cannot be distinctly improved. In addition, different from single cloud, a challenge is how to effectively verify query integrity when some cloud servers return incorrect or incomplete results in a multicloud situation. To ensure the data security, we propose an iterative encryption method to ensure the file privacy even if multiple cloud servers collude with each other. We use Bloom filter to map keywords and construct a tree index for each cloud server to achieve secure and efficient distributed keyword search. To verify the query integrity, we propose a fast verification algorithm to embed the file content and index information into the file ID. The analysis and experiments demonstrate the security and effectiveness of our scheme.

Multi-User Revocable Keyword Search Scheme for

With the rapid development of cloud computing, more and more users store their data in the cloud. Considering the privacy problem of the data sharing in the cloud, searchable encryption makes it possible to efficiently share and retrieve data in multi-user settings. The existing keyword search scheme of sharing the private key with authorized users to generate trapdoors may increase the risk of key exposure, and the scheme of encrypting the data with the secret key of each authorized user and generating a ciphertext for each user may not be suitable for data sharing between a large number of users. In this paper, we combine the secure IBBE system with the keywords search and propose the scheme to achieve safe and efficient multi-user data sharing in the cloud. Authorized users can perform keyword search directly on encrypted data without sharing the secret key, and for a shared file, the data owner only needs to encrypt one ciphertext for all authorized users. Besides, authorized users of shared files can be revoked. User authorization tables and IBBE ensure that revoked users cannot access files.

RDF keyword search using multiple indexes

Since SPARQL has been the standard language for querying RDF data, keyword search based on keywords-to-SPARQL translation attracts more intention. However, existing keyword search based on keywords-to-SPARQL translation have limitations that the schema used for keyword-to-SPARQL translation is incomplete so that wrong or incomplete answers are returned and advantages of indexes are not fully taken. To address the issues, an inter-entity relationship summary (ER-summary) is constructed by distilling all the inter-entity relationships of RDF data graph. On ER-summary, we draw circles around each vertex with a given radius r and in the circles we build the shortest property path index (SP-index), the shortest distance index (SD-index) and the r-neighborhoods index by using dynamic programming algorithm. Rather than searching for top-k subgraphs connecting all the keywords centered directly as most existing methods do, we use these indexes to translate keyword queries into SPARQL queries to realize exchanging space for time. Extensive experiments show that our approach is efficient and effective.

Keyword Search on Temporal Graphs

Archiving graph data over history is demanded in many applications, such as social network studies, collaborative projects, scientific graph databases, and bibliographies. Typically people are interested in querying temporal graphs. Existing keyword search approaches for graph-structured data are insufficient for querying temporal graphs. This paper initiates the study of supporting keyword-based queries on temporal graphs. We propose a search syntax that is a moderate extension of keyword search, which allows casual users to easily search temporal graphs with optional predicates and ranking functions related to timestamps. To generate results efficiently, we first propose a best path iterator, which finds the paths between two data nodes in each snapshot that is the “best” with respect to three ranking factors. It prunes invalid or inferior paths and maximizes shared processing among different snapshots. Then, we develop algorithms that efficiently generate top- $k$ query results. Extensive experiments verified the efficiency and effectiveness of our approach.

A Novel Methodology to Mitigate Keyword Guessing Attack using Keyword and Signature Hash

The importance of electronic data and its rapid growth leads to gradual increase to the data usage over the network servers and on the other side high priority is needed for the data security and privacy. The existing keyword search schemes for data retrieval from the centralized storage uses keyword as a valid parameter. Even though, keywords are encrypted and then used, intruders are able to guess keywords and can verify it using offline dictionary attack. The ability of guessing keywords by intruders reveals the stored data which affects data security and privacy. We need an additional parameter to the keyword used for search which will make the keyword guessing attack impossible. The additional parameter we used in our encryption framework is a signature file whose content needs to be independent of data. The content of signature file can be any data such as image, table, text, etc. which depends on the choice of user. This signature is hashed with keyword which makes the adversary difficult to guess the content of signature of the user. The existing approaches used keyword along with private key as search parameters, the guessing of appropriate keyword reveals the private key of user. In our framework, addition of signature along with keyword ensures both authentication as well as data privacy.

Efficient Duplication Free and Minimal Keyword Search in Graphs

Keyword search over a graph searches for a subgraph that contains a set of query keywords. A problem with most existing keyword search methods is that they may produce duplicate answers that contain the same set of content nodes (i.e., nodes containing a query keyword) although these nodes may be connected differently in different answers. Thus, users may be presented with many similar answers with trivial differences. In addition, some of the nodes in an answer may contain query keywords that are all covered by other nodes in the answer. Removing these nodes does not change the coverage of the answer but can make the answer more compact. The answers in which each content node contains at least one unique query keyword are called minimal answers in this paper. We define the problem of finding duplication-free and minimal answers, and propose algorithms for finding such answers efficiently. Extensive performance studies using two large real data sets confirm the efficiency and effectiveness of the proposed methods.

Related Axis: The Extension to XPath Towards Effective XML Search

We investigate the limitations of existing XML search methods and propose a new semantics, related relationship, to effectively capture meaningful relationships of data elements from XML data in the absence of structural constraints. Then we make an extension to XPath by introducing a new axis, related axis, to specify the related relationship between query nodes so as to enhance the flexibility of XPath. We propose to reduce the cost of computing the related relationship by a new schema summary that summarizes the related relationship from the original schema without any loss. Based on this schema summary, we introduce two indices to improve the performance of query processing. Our algorithm shows that the evaluation of most queries can be equivalently transformed into just a few selection and value join operations, thus avoids the costly structural join operations. The experimental results show that our method is effective and efficient in terms of comparing the effectiveness of the related relationship with existing keyword search semantics and comparing the efficiency of our evaluation methods with existing query engines.

An attentive self-organizing neural model for text mining

This paper utilizes an attention concept approach in text mining to address the deficiencies of existing keyword search engines. We show how an attention concept in conjunction with a traditional search approach can be used to develop an adaptive text mining model with user-oriented, time-based and attentive knowledge. Without changing a user’s search behavior, this paper considers some specific post-search operations as attentive targets for building the personalized interest base. This interest base is further shown on an interest map via the self-organizing map algorithm (SOM). By comparing the personalized interest map, the original search results from a keyword search engine are re-ranked. Experimental results demonstrate that the attentive search mechanism is able to improve user satisfaction.