There have been many researches on indexing and querying XML data. One of the important themes is how to efficiently process XML query represented by path expression. The most straightforward approach to process these queries is to traverse the hierarchy of XML document by top-down or bottom-up manner. However it may be fairly inefficient because the overhead of traversing the XML data can be high. In addition, most of the proposed indexing and retrieval schemes assume static environment where there are no updates on the parts of XML data. In this paper we propose a novel indexing and query processing scheme that can process both XML query represented by path expression efficiently and dynamic updates on XML data promptly. Experimental results show that our proposed scheme achieves better performance than that of the previous ones.

This paper reports a 24GHz ISM band radar module for pedestrian detection in crosswalks. The radar module is composed of an RF transceiver board, a baseband board, and a microcontroller unit board. The radar signal is a sawtooth frequency-modulated continuous-wave signal with a center frequency of 24.15GHz, a bandwidth of 200MHz, a chirp length of 80µs, and a pulse repetition interval of 320µs. The radar module can detect a pedestrian on a crosswalk with a width of 4m and a length of 14m. The radar outputs the range, angle, and speed of the detected pedestrians every 50ms by radar signal processing and consumes 7.57W from 12V power supply. The size of the radar module is 110×70mm2.

In this paper, an effective index structure for dynamic main memory database systems, which we call the T2-tree, is presented. A notion of a thread pointer is introduced to overcome some of the limitations of the T-tree and the T*-tree. There are several advantages to this structure. First, the T2-tree reduces the number of rotate operations and the overhead required for balancing the tree by restraining new node creation and deletion. Second, the T2-tree shows good performance for sequential search of range queries as these requests can be effectively handled using the successor pointer. Finally, the T2-tree allows for higher space utilization amplicating the aforementioned benefits. These advantages are obtained with minimal changes to the existing T-tree structure. Experimental studies showing evidence of the benefits of the T2-tree are also presented.

Multiple access based on energy spreading transform (EST) in [1] has been shown to effectively separate multiuser signals in an iterative manner. In this paper, an optimum hard-decision detector for the EST-based multiple access is proposed. The proposed scheme employs minimum mean square error (MMSE) processing at each iteration to enhance the performance of the original scheme. Analysis and simulation results show the significant performance improvement of the proposed scheme over the original method.

Efficient query processing in multi-dimensional indexing structures is an important issue for multimedia data applications. In this paper, we propose incremental k-nearest neighbor query (k-NNQ) and range query algorithms for R-tree based structures. The novel aspect of these algorithms is that they make use of the notion of VP filtering, a concept borrowed from the MVP-tree. The filtering notion allows for delaying of computational overhead until absolutely necessary. By so doing, we attain considerable performance benefits while paying insignificant overhead during the construction of the index structure. We implemented our algorithms and carried out experiments to demonstrate the capability and usefulness of our method. Results show that improvements range from 8% to 23% in response time for the experimental environment that we considered.

Most of the existing studies on storing and searching XML documents effectively manipulate each XML document independently. Therefore, techniques for storing XML documents together that have similar meaning or structure are required for efficiency. Also, as a unified access method for various XML storage systems that have different storage forms, studies to integrate the DTD or XML schema of each storage system into one are required, because many XML documents do not have a particular DTD or XML schema, or XML documents can be written in various ways. Therefore, studies on the integration techniques for XML instances are needed. The XML integration technique can be used effectively in the case of constructing a data warehouse for heterogeneous XML storage systems. The proposed integration techniques remove the space duplicated for the same elements in XML documents. The proposed techniques significantly reduce the search time for general queries on the XML documents because it stores the related parts in XML documents close.