Abstract The need for large-scale data sharing between autonomous and possibly heterogeneous decentralized systems on the Web led to the concept of P2P database systems. In this paper, we present D3- P2P a new architecture which allows to manage a distributed and replicated database, in Peer-To-Peer (P2P) system with high node dynamicity. This architecture is based on a quorum system to... The need for large-scale data sharing between autonomous and possibly heterogeneous decentralized systems on the Web led to the concept of P2P database systems. In this paper, we present D3- P2P a new architecture which allows to manage a distributed and replicated database, in Peer-To-Peer (P2P) system with high node dynamicity. This architecture is based on a quorum system to solve problems of concurrent update and nodes failure. The proposed architecture allows assigning a unique timestamp to each distributed transaction in order to build a local precedence order graph in each peer, to select the server replicas and to coordinate the distributed execution of the transaction. To avoid deadlock between nodes, we propose a fully distributed algorithm. Read More Read Less

Abstract In this paper, we present a novel approach to generate Alloy code from Natural Language (NL) constraints. The proposed research is basically an extension of two projects, NL2OCL and UML2Alloy.Our method uses Natural Language Processing (NLP) and Model Transformation (MT) to transform constraints expressed in NL to Alloy. We do not directly transform NL to Alloy, instead we use multiple... In this paper, we present a novel approach to generate Alloy code from Natural Language (NL) constraints. The proposed research is basically an extension of two projects, NL2OCL and UML2Alloy.Our method uses Natural Language Processing (NLP) and Model Transformation (MT) to transform constraints expressed in NL to Alloy. We do not directly transform NL to Alloy, instead we use multiple intermediate translations such as NL2SBVR and SBVR2OCL and finally OCL2Alloy. Such intermediate translations help us to monitor the whole process of translation and produce intermediate artifacts such as OCL constraints, which can be used for documentation purposes. and ensure that actual semantics of NL have been transformed to Alloy. The generated Alloy code can then be used to check if the original NL constraints are consistent. We also introduce the use of OMG's standard SBVR in translation of NL to formal languages. The NL2Alloy approach is also implemented as an Eclipse plugin. Read More Read Less

Abstract Emergency management of sudden disasters needs a quick and efficient decision made by a group. The authors propose a visual discussion technique in group decision making of sudden disasters and construct the main technique process based on visualization theory. Based on this, Through the key techniques are researched and implemented. As for Multiagents in the discussion, they can obtain more... Emergency management of sudden disasters needs a quick and efficient decision made by a group. The authors propose a visual discussion technique in group decision making of sudden disasters and construct the main technique process based on visualization theory. Based on this, Through the key techniques are researched and implemented. As for Multiagents in the discussion, they can obtain more accurate cognition of current sudden disaster situation and form efficient emergency predetermined plan by discussion and analysis in the short time. Read More Read Less

Abstract Question answering systems provide answer to the questions using various question processing techniques and extracts answers from a set of documents. Finding the exact answer is more interesting and useful than getting a list of documents to look through and find the answer manually. Question answering is not same as a traditional document retrieval search engine where a set of... Question answering systems provide answer to the questions using various question processing techniques and extracts answers from a set of documents. Finding the exact answer is more interesting and useful than getting a list of documents to look through and find the answer manually. Question answering is not same as a traditional document retrieval search engine where a set of relevant documents are returned in response of the query, whereas, in the question answering systems the response of the query is a concise and exact answer to the question. Typically, Question Classification (QC) is the first step in a Question Answering (QA) system. This phase is responsible for finding out the type of the expected answer by pruning out the extra information that is not relevant to extract the answer. Almost all the previous QC algorithms evaluated their work on the basis of a common class hierarchy already defined. The coarse grained classes Location, Entity and Numeric in the existing hierarchy have a fine grained class Other. We present the framework to create new fine grained classes to replace the Other classes. We also discuss the motivation behind the replacement and how the new fine grained classes may support the answer extraction. Additionally, we also present an automatic hierarchy creation method to add new class nodes using WordNet and Noun phrase parsing. Read More Read Less

Abstract In the article we describe the approach to parallel implementation of elementary operations for textual data categorization. In the experiments we evaluate parallel computations of similarity matrices and k-means algorithm. The test datasets have been prepared as graphs created from Wikipedia articles related with links. W also present the approach to computing pairs of eigenvectors and eigenvalues for visualizations of... In the article we describe the approach to parallel implementation of elementary operations for textual data categorization. In the experiments we evaluate parallel computations of similarity matrices and k-means algorithm. The test datasets have been prepared as graphs created from Wikipedia articles related with links. W also present the approach to computing pairs of eigenvectors and eigenvalues for visualizations of the datasets. The implemented basic operations: computing similarity matrix, data clustering and spectral analysis have been used in our system for visualization of the Wikipedia categories on SOM as well as in a system for categorization search results in Wikipedia. Read More Read Less

Abstract This paper presents the Snippet System, a new operating system environment that aims at providing enhanced document management facilities. For this, the proposed system utilizes a novel document model based on finer-grained entities, so-called Snippets. These support Relations, which capture the context of individual document excerpts. Snippets furthermore enable a flexible reuse of documents, i.e., user-defined excerpts can be included... This paper presents the Snippet System, a new operating system environment that aims at providing enhanced document management facilities. For this, the proposed system utilizes a novel document model based on finer-grained entities, so-called Snippets. These support Relations, which capture the context of individual document excerpts. Snippets furthermore enable a flexible reuse of documents, i.e., user-defined excerpts can be included in several other documents with only selected properties remaining synchronized between different instances. Moreover, dedicated mechanisms allow for the efficient retrieval of these instances and thus support the user in keeping track of reused excerpts and synced properties. The Snippet System relies on a component-based authoring tool architecture that enables different authoring tools to collaborate for handling documents. This allows for combining the contents created by various tools in a single document, independently of the type of content and tools involved, thus making possible the reuse of documents and the definition of Relations across tool boundaries. Read More Read Less

Abstract Collecting data from sensor nodes is the ultimate goal of Wireless Sensor Networks. This is performed by transmitting the sensed measurements to some data collecting station. In sensor nodes, radio communication is the dominating consumer of the energy resources which are usually limited. Summarizing the sensed data internally on sensor nodes and sending only the summaries will considerably save energy.... Collecting data from sensor nodes is the ultimate goal of Wireless Sensor Networks. This is performed by transmitting the sensed measurements to some data collecting station. In sensor nodes, radio communication is the dominating consumer of the energy resources which are usually limited. Summarizing the sensed data internally on sensor nodes and sending only the summaries will considerably save energy. Clustering is an established data mining technique for grouping objects based on similarity. For sensor networks, k-center clustering aims at grouping sensor measurements in groups, each contains similar measurements. In this paper we propose a novel resource-aware -center clustering algorithm called: SenClu. Our algorithm immediately detects new trends in the drifting sensor data stream and follows them. SenClu powerfully uses a lightweighted decaying technique that gives lower influence to old data. As sensor data are usually noisy, our algorithm is also outlier-aware. In thorough experiments on drifting synthetic and real world data sets, we show that SenClu outperforms two state-of-the-art algorithms by producing higher clustering quality and following trends in the stream, while consuming nearly the same amount of energy. Read More Read Less

Abstract This study explores the reason for non-usage and abandonment of microblogging. While previous studies mainly focused on individual behaviors associated with the use of social media, this research identifies why people do not use, or terminate their microblogging accounts. Studying the reasons for non-usage and abandonment is important as it helps organizations devise strategies to counteract this behavior by addressing... This study explores the reason for non-usage and abandonment of microblogging. While previous studies mainly focused on individual behaviors associated with the use of social media, this research identifies why people do not use, or terminate their microblogging accounts. Studying the reasons for non-usage and abandonment is important as it helps organizations devise strategies to counteract this behavior by addressing nonusers' concerns. First, focus group interviews were conducted to uncover non-usage reasons. The elicited reasons were then used to construct a survey instrument and administered. Our results suggests that preference for other technologies, privacy concern and time constraints are the top three reasons contributing to the non-use and abandonment of microblogging accounts. The paper also proposes potential improvements to microblogs to attract more users. Read More Read Less