Shengfei Shi

Unsupervised Outlier Detection in Sensor Networks Using Aggregation Tree

In the applications of sensor networks, outlier detection has attracted more and more attention. The identification of outliers can be used to filter false data, find faulty nodes and discover interesting events. A few papers have been published for this issue. However some of them consume too much communication, some of them need user to pre-set correct thresholds, some of them generate approximate results rather than exact ones. In this paper, a new unsupervised approach is proposed to detect global top noutliers in the network. This approach can be used to answer both snapshot queries and continuous queries. Two novel concepts, modifier setand candidate setfor the global outliers, are defined in the paper. Also a commit-disseminate-verifymechanism for outlier detection in aggregation tree is provided. Using this mechanism and the these two concepts, the global top noutliers can be detected through exchanging short messages in the whole tree. Theoretically, we prove that the results generated by our approach are exact. The experimental results show that our approach is the most communication-efficient one compared with other existing methods. Moreover, our approach does not need any pre-specified threshold. It can be easily extended to multi-dimensional data, and is suitable for detecting outliers of various definitions.

A music data model and its application

A music data model, its query language and its application are proposed in this paper. Firstly, a music data model and its algebraic operations are given, which can be used to describe and manipulate musical data efficiently. Secondly, a structured query language on the model is proposed, which can be used to define and manage musical data. Finally, a digital music library, one of the applications of this model, is presented, which can be used to retrieve musical information, especially against musical instruments.

The design and implementation of a digital music library

The design and implementation of Harbin Institute of Technology—Digital Music Library (HIT-DML) is presented in this paper. Firstly, a novel framework, a music data model, and a query language are proposed as the theoretical foundation of the library. Secondly, music computing algorithms used in the library for feature extracting and matching are described. In addition, indices are introduced for both mining themes of music objects and accelerating content-based information retrieval. Finally, experimental results on the indices and the current development of the library are provided.HIT-DML is distinguished by the following points. First, it is inherently based on database systems, and combines database technologies with multimedia technologies seamlessly. Musical data are structurally stored. Second, it has a solid theoretical foundation, from framework and data model to query language. Last, it can retrieve musical information based on content against different kinds of musical instruments. The indices used, also power the library.

InfiniteDB: a pc-cluster based parallel massive database management system

This paper describes a PC-cluster based parallel DBMS, InfiniteDB, developed by the authors. InfiniteDB aims at efficiently storing and processing of massive databases in response to the rapidly growing in database size and the need of high performance analyzing of massive databases. It supports the parallelisms of intra-query, inter-query, intra-operation, inter-operation and pipelining. It provides effective strategies for processing massive databases including the multiple data declustering methods, the declustering-aware algorithms for the execution of relational operations and other database operations, and the adaptive query optimization method. It also provides the functions of parallel data warehousing and data mining, the coordinator-wrapper mechanism to support the integration of heterogeneous information resources on the Internet, and the fault tolerant and resilient infrastructures. It has been used in many applications and has proved quite effective for storing and processing massive databases in practice.

Cell abstract indices for content-based approximate query processing in structured peer-to-peer data systems

In this paper, cell abstract indices are presented to process content-based approximate queries in structured P2P data systems. It can be used to search as few peers as possible but get as many returns satisfying users’ queries as possible on the guarantee of high autonomy of peers. Also, cell abstract indices have low system cost, can improve the query processing speed, and support very frequent updates and the set information publishing method. Simulation experiments are performed and analyzed to show the effectiveness of the proposed indices.

An Approach to Content-Based Approximate Query Processing in Peer-to-Peer Data Systems

In recent years there has been a significant interest in peer-to-peer (P2P) environments in the community of data management. However, almost all works, as far, focused on exact query processing in current P2P data systems. The autonomy of peers also doesn’t be considered enough. In addition, the system cost is very high because the information publishing method of shared data is based on each document instead of document set.

Structure-aware music resizing using lyrics

World wide web provides plenty of multimedia resources for creating rich media web applications. However, the collected music and other media resources always mismatch in the metric of time length. Existent music resizing approaches suffer from perceptual artifacts which degrade the performance of resized music. In this paper, a novel structure-aware music resizing approach is proposed. Through lyrics analysis, our approach can compress different parts of a music piece in variant compression rates. Experimental results show that the proposed method can effectively generate resized songs with good quality.

HIT-DML: A Novel Digital Music Library

The design and implementation of Harbin Institute of Technology-Digital Music Library (HIT-DML) is presented in this paper. HIT-DML adopts a novel framework which is inherently based on database systems. In this framework, musical data is structurally stored in the database, some algorithms of musical computation are implemented as algebraic mirco-operations in the database management system, and thus database technologies and multimedia technologies are combined seamlessly. A musical feature-matching algorithm and the appropriate dynamic index are also applied in HIT-DML. HIT-DML can retrieve musical information based on content, especially against different kinds of musical instruments.

TiCom: A Time-Compensation Based Review Ranking Algorithm for Mobile Clients

Mobile environment has been one of focuses of computing, communication and management. Mobile review ranking problem, for the first time, is brought out in this paper. Also, a novel ranking algorithm, TiCom, is proposed for mobile review ranking. TiCom is based on the idea of time compensation, and is used to prevent fresh voting item from being ranked too high or too low. Experimental results show that TiCom effectively improves the review process, e.g. music review ranking, especially in mobile environments.

MuSQL: a music structured query language

A music structured query language, called MuSQL, is presented in this paper. MuSQL consists of a schema definition sub-language and a data manipulation sub-language. The former is composed of schema-setup statements, schema-alter statements, and schema-drop statements. The latter is composed of selection, retrieval, extraction, insertion, update, deletion, commission, rollback, and other statements. MuSQL can be used to cut, delete and merge content of music, insert, delete and extract features of music, and exactly or approximately search music pieces, especially in the processing of music based on content. Also, it makes some music processing operations easier due to its built-in semantics. MuSQL has been implemented in a music data management system.