Abstract: Keyword search is integrated in many applications on account of the convenience to convey users' query intention. Recently, answering keyword queries on XML data has drawn the attention of web and database communities, because the success of this research will relieve users from learning complex XML query languages, such as XPath/XQuery, and/or knowing the underlying schema of the queried XML data. As a result, information in XML data can be discovered much easier.To model the result of answering keyword queries on XML data, many LCA (lowest common ancestor) based notions have been proposed. In this paper, we focus on ELCA (Exclusive LCA) semantics, which is first proposed by Guo et al. and afterwards named by Xu and Papakonstantinou. We propose an algorithm named Hash Count to find ELCAs efficiently. Our analysis shows the complexity of Hash Count algorithm is O(kd|S1|), where k is the number of keywords, d is the depth of the queried XML document and |S1| is the frequency of the rarest keyword. This complexity is the best result known so far. We also evaluate the algorithm on a real DBLP dataset, and compare it with the state-of-the-art algorithms. The experimental results demonstrate the advantage of Hash Count algorithm in practice.

Abstract: We here present jmzML, a Java API for the Proteomics Standards Initiative mzML data standard. Based on the Java Architecture for XML Binding and XPath-based XML indexer random-access XML parser, jmzML can handle arbitrarily large files in minimal memory, allowing easy and efficient processing of mzML files using the Java programming language. jmzML also automatically resolves internal XML references on-the-fly. The library (which includes a viewer) can be downloaded from http://jmzml.googlecode.com.

Abstract: Dealing with structure and content semantics underlying semistructured documents is challenging for any task of document management and knowledge discovery conceived for such data. In this work we address the novel problem of clustering semantically related XML documents according to their structure and content features. XML features are generated by enriching syntactic with semantic information based on a lexical knowledge base. The backbone of the proposed framework for the semantic clustering of XML documents is a data representation model that exploits the notion of tree tuple to identify semantically cohesive substructures in XML documents and represent them as transactional data. This framework is equipped with two clustering algorithms based on different paradigms, namely centroid-based partitional clustering and frequent-itemset-based hierarchical clustering. An extensive experimental evaluation was conducted on real data sets from various domains, showing the significance of our approach as a solution for the semantic clustering of XML documents.

Abstract: Peers in a peer-to-peer data management system often have heterogeneous schemas and no mediated global schema. To translate queries across peers, we assume each peer provides correspondences between its schema and a small number of other peer schemas. We focus on query reformulation in the presence of heterogeneous XML schemas, including data---metadata conflicts. We develop an algorithm for inferring precise mapping rules from informal schema correspondences. We define the semantics of query answering in this setting and develop query translation algorithm. Our translation handles an expressive fragment of XQuery and works both along and against the direction of mapping rules. We describe the HePToX heterogeneous P2P XML data management system which incorporates our results. We report the results of extensive experiments on HePToX on both synthetic and real datasets. We demonstrate our system utility and scalability on different P2P distributions.

Abstract: Most solutions for Wireless Sensor Networks (WSN) come equipped with their own architectural concepts which raise the problem of possible incompatibility of computer networks and the WSN. Often gateway concepts are used to overcome this problem. But this is not the best solution on the long term. Other research fields and industrial domains are heading for universal cross domain architecture concepts based on internet technologies that are more mature and better understood. The IETF 6LoWPAN working group provides the groundings for standardized communication using existing network protocols like IPv6 also in low power radio networks. A big challenge when deploying further application layer network protocols on top of 6LoWPAN is the message size of existing mostly XML based protocols which does not meet the resource requirements of deeply embedded devices without further research efforts. This paper presents different data compression techniques for the Devices Profile of Web Services (DPWS) to be applied in 6LoWPAN networks. Therefore, we analyze a realistic scenario. We determined 18 message types in the scenario and compressed and encoded all messages by using existing schemes and tools. For the first time, we also investigate on the Efficient XML Interchange (EXI) format for DPWS.

Abstract: The world-wide web (WWW) is often considered to be the world's largest database and the eXtensible Markup Language (XML) is then considered to provide its datamodel. Adopting this view we have to deal with a distributed database. This raises the question, how to obtain a suitable distribution design for XML documents. In this paper horizontal and vertical fragmentation techniques are generalised from the relational datamodel to XML. Furthermore, splitting will be introduced as a third kind of fragmentation. Then it is shown how relational techniques for de ning reasonable fragments can be applied to the case of XML.

Abstract: World is shrinking each day through the use of Internet and people are communicating better than before in this widely distributed network. There is a great need to manage this communication over various networks supporting different specifications. One of the widely used techniques for this type of data management is XML data interchange format. Google developers recently introduced Protocol Buffer as an alternative to XML claiming that it overcomes the shortcomings suffered by XML. This paper compares XML and Protocol Buffer data formats by extensive analysis of the two. The paper evaluates the claims made by Google by developing an algorithm to map an existing XML to Protocol Buffer format and drawing any conclusion on the efficiency and effectiveness of this format as compared to XML. It can be hoped that this work will contribute to the upcoming research in this field as people are looking for more robust data interchange format for the future of the Internet.

Abstract: Extensible Markup Language (XML) is playing an increasing important role in web services and database systems. However, the task of XML parsing is often the bottleneck, and as a result, the target of acceleration using custom hardware or multicore CPUs. In this paper, we detail the design of the first complete field programmable gate array (FPGA) accelerator capable of XML well-formed checking, schema validation, and tree construction at a throughput of 1 cycle per byte (CPB). This is a significant advancement from 40 CPB, the best previous reported commercial result. We demonstrate our design on a Xilinx Virtex-5 board, which successfully saturates a 1 Gbps Ethernet link.

Abstract: In this article, we address the problem of delayed query processing raised by tree-based index structures in wireless broadcast environments, which increases the access time of mobile clients. We propose a novel distributed index structure and a clustering strategy for streaming XML data that enables energy and latencyefficient broadcasting of XML data. We first define the DIX node structure to implement a fully distributed index structure which contains the tag name, attributes, and text content of an element, as well as its corresponding indices. By exploiting the index information in the DIX node stream, a mobile client can access the stream with shorter latency. We also suggest a method of clustering DIX nodes in the stream, which can further enhance the performance of query processing in the mobile clients. Through extensive experiments, we demonstrate that our approach is effective for wireless broadcasting of XML data and outperforms the previous methods.

Abstract: After its introduction in 1998, XML has quickly emerged as the de facto exchange format for textual data. Only ten years later, the amount of information that is being processed day by day, locally and globally, has virtually exploded, and no end is in sight. Correspondingly, many XML documents and collections have become much too large for being retrieved in their raw form – and this is where database technology gets into the game. This thesis describes the design of a full-fledged XML storage and query architecture, which represents the core of the Open Source database system BASEX. In contrast to numerous other works on XML processing, which either focus on theoretical aspects or practical implementation details, we have tried to bring the two worlds together: well-established and novel concepts from database technology and compiler construction are consolidated to a powerful and extensible software architecture that is supposed to both withstand the demands of complex real-life applications and comply with all the intricacies of the W3C Recommendations. In the Storage chapter, existing tree encodings are explored, which allow XML documents to be mapped to a database. The Pre/Dist/Size triple is chosen as the most suitable encoding and further optimized by merging all XML node properties into a single tuple, compactifying redundant information, and inlining attributes and numeric values. The address ranges of numerous large-scale and real-life XML instances are analyzed to find an optimal tradeoff between maximum document and minimum database size. The process of building a database is described in detail, including the import of tree data other than XML and the creation of main memory database instances. As one of the distinguishing features, the resulting storage is enriched by light-weight structural, value and full-text indexes, which speed up query processing by orders of magnitudes. The Querying chapter is introduced with a survey on state of the art XML query languages. We give some insight into the design of an XQuery processor and then focus on the optimization of queries. Beside classical concepts, such as constant folding or static typing, many optimizations are specific to XML: location paths are rewritten to access less XML nodes, and FLWOR expressions are reorganized to reduce the algorithmic com-

Abstract: We present the design philosophy, implementation, and various applications of an XML-based genetic programming (GP) framework (XGP). The key feature of XGP is the distinct representation of genetic programs as DOM parsing trees featuring corresponding flat XML text. XGP contributes to the achievements of: (i) fast prototyping of GP by using the standard built-in API of DOM parsers for manipulating the genetic programs, (ii) human readability and modifiability of the genetic representations, (iii) generic support for the representation of the grammar of a strongly typed GP using W3C-standardized XML schema; (iv) inherent inter-machine migratability of the text-based genetic representation (i.e., the XML text) in the distributed implementations of GP.

Abstract: The notion of certain answers arises when one queries incompletely specified databases, eg, in data integration and exchange scenarios, or databases with missing information While in the relational case this notion is well understood, there is no natural analog of it for XML queries that return documentsWe develop an approach to defining certain answers for such XML queries, and apply it in the settings of incomplete information and XML data exchange We first revisit the relational case, and show how to present the key concepts related to certain answers in a new model-theoretic language This new approach naturally extends to XML We prove a number of generic, application-independent results about computability and complexity of certain answers produced by it We then turn our attention to a pattern-based XML query language with trees as outputs, and present a technique for computing certain answers that relies on the notion of a basis of a set of trees We show how to compute such bases for documents with nulls and for documents arising in data exchange scenarios, and provide complexity bounds While in general complexity of query answering in XML data exchange could be high, we exhibit a natural class of XML schema mappings for which not only query answering, but also many static analysis problems can be solved efficiently

Abstract: One of the critical challenges in embedded sensor actor networks is the communication between the diversity of widespread nodes. XML-based message formats are already widely adopted in other IT domains such as the Web and would be perfectly suited for data exchange in heterogeneous environments. Despite all its strengths, the common markup language cannot be adopted on small embedded devices with limited resources due to its verbosity and associated processing overhead. The paper describes an innovative source code generation technique by means of W3C's Efficient XML Interchange (EXI) format that enables the efficient usage of XML-based messages on small devices with limited resources. The outcome is an EXI Processor that allows an end-to-end XML-based communication between systems ranging from powerful workstations to microcontroller-based systems. Particularly, the paper emphasizes the flexibility with regard to alter an exchange format and its minimal adaption efforts due to the generated EXI Processor. An example application proves the applicability of the proposed approach and demonstrates a real life show-case for XML-based Web service communication on microcontroller-based devices.

Abstract: Advanced Applications and Structures in XML Processing: Label Streams, Semantics Utilization and Data Query Technologies reflects the significant research results and latest findings of scholars worldwide, working to explore and expand the role of XML. This collection represents an understanding of XML processing technologies in connection with both advanced applications and the latest XML processing technologies that is of primary importance. It provides the opportunity to understand topics in detail and discover XML research at a comprehensive level.

Abstract: Objectives: The goal of this article is to examine whether W3C XML Schema provides a practicable solution for the semantic validation of standard-based electronic health record (EHR) documents. With semantic validation we mean that the EHR documents are checked for conformance with the underlying archetypes and reference model. Methods: We describe an approach that allows XML Schemas to be derived from archetypes based on a specific naming convention. The archetype constraints are augmented with additional components of the reference model within the XML Schema representation. A copy of the EHR document that is transformed according to the before-mentioned naming convention is used for the actual validation against the XML Schema. Results: We tested our approach by semantically validating EHR documents conformant to three different ISO/EN 13606 archetypes respective to three sections of the CDA implementation guide “Continuity of Care Document (CCD)” and an implementation guide for diabetes therapy data. We further developed a tool to automate the different steps of our semantic validation approach. Conclusions: For two particular kinds of archetype prescriptions, individual transformations are required for the corresponding EHR documents. Otherwise, a fully generic validation is possible. In general, we consider W3C XML Schema as a practicable solution for the semantic validation of standard-based EHR documents.

Abstract: XML Schema is employed for describing the type and structure of information contained in XML documents. Schema evolution means that a schema is modified and the effects of the modification on instances are faced. XSUpdate is a language that allows to easily identify parts of an XML Schema, apply a modification primitive on them and define an adaptation for associated documents. Purpose of this paper is to present the engine we developed for the evaluation of XSUp-date statements against XML Schemas and associated documents. The presented engine relies on the translation of XSUpdate statements in XQuery Update expressions.

Abstract: Because of increasing use of XML data on the internet, the need for an efficient method of storing and querying XML data is vital. So far, two major types of system for XML data management have been introduced: XML Enabled systems and XML native systems. The former uses relational database system for storing and querying XML data and the latter is a special XML database system which is based on XML data model. Since relational database systems are more mature than XML native systems, it seems that the use of abilities and efficiencies of relational systems is more economical. In this article, we have introduced a new relational schema named XLight for storing and processing XML data, and we have compared it with some similar methods.

Abstract: The adoption of XML as the default data interchange format and the standardisation of the XPath and XQuery languages has resulted in significant research in the development and implementation of XML databases capable of processing queries efficiently. The ever-increasing deployment of XML in industry and the real-world requirement to support efficient updates to XML documents has more recently prompted research in dynamic XML labelling schemes. In this paper, we provide an overview of the recent research in dynamic XML labelling schemes. Our motivation is to define a set of properties that represent a more holistic dynamic labelling scheme and present our findings through an evaluation matrix for most of the existing schemes that provide update functionality.

Abstract: Techniques for fast and scalable generation and aggregation of XML data are described. In an example embodiment, an XML query that requests data from XML documents is received. The XML query is evaluated to determine one or more XML results. For each particular XML result, evaluating the XML query comprises: instantiating a particular data structure that represents the particular XML result, where the particular data structure is encoded in accordance with tags specified in the XML query but does not store the tags; and storing, in the particular data structure, one or more locators that respectively point to one or more fragments in the XML documents, where the particular data structure stores the one or more locators but does not store the one or more fragments. On demand, in response to a request indicating the particular XML result, a serialized representation of the particular XML result is generated based at least on the particular data structure.

Abstract: An architecture that that extends conventional computer programming languages that compile into an instance of an extensible markup language (XML) document object model (DOM) to provide support for XML literals in the underlying programming language. This architecture facilitates a convenient short cut by replacing the complex explicit construction required by conventional systems to create an instance of a DOM with a concise XML literal for which conventional compilers can translate into the appropriate code. The architecture allows these XML literals to be embedded with expressions, statement blocks or namespaces to further enrich the power and versatility. In accordance therewith, context information describing the position and data types that an XML DOM can accept can be provided to the programmer via, for example, an integrated development environment. Additionally, the architecture supports escaping XML identifiers, a reification mechanism, and a conversion mechanism to convert between collections and singletons.

Abstract: XML has become the standard document representation for many popular tools in various domains. When multiple authors collaborate to produce a document, they must be able to work in parallel and periodically merge their efforts into a single work. While there exist a small number of three-way XML merging tools, their performance could be improved in several areas and they lack any form of user interface for resolving conflicts.In this paper, we present an implementation of a three-way XML merge algorithm that is faster, uses less memory and is more precise than existing tools. It uses a specialized versioning tree data structure that supports node identity and change detection. The algorithm applies the traditional three-way merge found in GNU diff3 to the children of changed nodes. The editing operations it supports are addition, deletion, update, and move. A graphical interface for visualizing and resolving conflicts is also provided. An evaluation experiment was conducted comparing the proposed algorithm with three other tools on randomly generated XML data.

Abstract: : The Department of Defense (DoD) Network-Centric data sharing strategy for the Global Information Grid (GIG) is to XMLize all data. The goal of this strategy is to ensure all data is visible, usable and interoperable, when and where needed, to accelerate decision cycles. However, this XML-based data approach comes at the cost of limiting real-time network edge device connectivity to the GIG because they are seldom able to meet the necessary bandwidth and processing requirements due to XML's intrinsic nature of being verbose and often complex to process. This research explores a powerful and robust solution to XML's network depth limits by means of the World Wide Web Consortium's (W3C) proposed alternative XML format, Efficient XML Interchange (EXI). The EXI format removes redundant tags and values from XML documents and encodes numeric content in a binary format. This format delivers significant file size savings and processing efficiencies compared to existing practices. The evolution of XML's path to EXI is summarized based on the results of the XML Binary Characterization (XBC) working group and the W3C's design points of XML. Followed are recommended steps for EXI development and enterprise integration, focusing on a public open source licensing philosophy. EXI algorithms are described with detailed explanations, Java code samples, and part-task test XML documents. Experiments are conducted evaluating the effectiveness of EXI for DoD tactical use and is followed with a recommended optimal EXI configuration. Several predictive models of EXI's performance are presented to enable potential EXI adopters a measurement tool of expected EXI benefit for various XML domains. This research concludes that for XML-based data, a doubling of bandwidth potential is achievable and CPU burdens minimized when EXI is applied.

Abstract: The increasing volume of data stored as XML documents makes fragmentation techniques an alternative to the performance issues in query processing. Fragmented databases are feasible only if there is a transparent way to query the distributed database. Fragments allow for intra-query parallel processing and data reduction. This paper presents our methodology for XQuery query processing over distributed XML databases. The methodology comprises the steps of query decomposition, data localization, and global optimization. This methodology can be used in an XML database or in a system that publishes homogeneous views of semi-autonomous databases. An implementation has been done and experimental results can achieve performance improvements of up to 95% when compared to the centralized environment.

Abstract: XML has emerged as the standard for information representation over the Internet. It is critical to store and query XML data to exploit the full power of the new technology. However, most enterprises today have long secured the use of relational databases. Thus, simply replacing relational databases with a pure XML database is not a good choice. It is thus crucial to map XML data into relational data. This paper studies the performance evaluation of storing XML documents into relational databases and identifies which mapping approach is best suited for which business environment. The performance results for all approaches are presented and a number of interesting results obtained from these evaluations are highlighted.