Toward Entity-Aware Search

As the Web has evolved into a data-rich repository, with the standard "page view," current search engines are becoming increasingly inadequate for a wide range of query tasks. While we often search for various data "entities" (e.g., phone number, paper PDF, date), today's engines only take us indirectly to pages. In my Ph.D. study, we focus on a novel type of Web search that is aware of data entities inside pages, a significant departure from traditional document retrieval. We study the various essential aspects of supporting entity-aware Web search. To begin with, we tackle the core challenge of ranking entities, by distilling its underlying conceptual model Impression Model and developing a probabilistic ranking framework, EntityRank, that is able to seamlessly integrate both local and global information in ranking. We also report a prototype system built to show the initial promise of the proposal. Then, we aim at distilling and abstracting the essential computation requirements of entity search. From the dual views of reasoning--entity as input and entity as output, we propose a dual-inversion framework, with two indexing and partition schemes, towards efficient and scalable query processing. Further, to recognize more entity instances, we study the problem of entity synonym discovery through mining query log data. The results we obtained so far have shown clear promise of entity-aware search, in its usefulness, effectiveness, efficiency and scalability

Restricted Conformal Property of Compressive Sensing

Energy and direction are tow basic properties of a vector. A discrete signal is a vector in nature. RIP of compressive sensing can not show the direction information of a signal but show the energy information of a signal. Hence, RIP is not complete. Orthogonal matrices can preserve angles and lengths. Preservation of length can show energies of signals like RIP do; and preservation of angle can show directions of signals. Therefore, Restricted Conformal Property (RCP) is proposed according to preservation of angle. RCP can show the direction of a signal just as RIP shows the energy of a signal. RCP is important supplement and development of RIP. Tow different proofs of RCP are given, namely, RCP_JL and RCP_IP.Comment: 11 pages, 4 figure

A New SLNR-based Linear Precoding for Downlink Multi-User Multi-Stream MIMO Systems

Signal-to-leakage-and-noise ratio (SLNR) is a promising criterion for linear precoder design in multi-user (MU) multiple-input multiple-output (MIMO) systems. It decouples the precoder design problem and makes closed-form solution available. In this letter, we present a new linear precoding scheme by slightly relaxing the SLNR maximization for MU-MIMO systems with multiple data streams per user. The precoding matrices are obtained by a general form of simultaneous diagonalization of two Hermitian matrices. The new scheme reduces the gap between the per-stream effective channel gains, an inherent limitation in the original SLNR precoding scheme. Simulation results demonstrate that the proposed precoding achieves considerable gains in error performance over the original one for multi-stream transmission while maintaining almost the same achievable sum-rate.Comment: 8 pages, 1 figur

Adaptive model for recommendation of news

Most news recommender systems try to identify users' interests and news' attributes and use them to obtain recommendations. Here we propose an adaptive model which combines similarities in users' rating patterns with epidemic-like spreading of news on an evolving network. We study the model by computer agent-based simulations, measure its performance and discuss its robustness against bias and malicious behavior. Subject to the approval fraction of news recommended, the proposed model outperforms the widely adopted recommendation of news according to their absolute or relative popularity. This model provides a general social mechanism for recommender systems and may find its applications also in other types of recommendation.Comment: 6 pages, 6 figure

Generalized Clifford Algebras as Algebras in Suitable Symmetric Linear Gr-Categories

By viewing Clifford algebras as algebras in some suitable symmetric Gr-categories, Albuquerque and Majid were able to give a new derivation of some well known results about Clifford algebras and to generalize them. Along the same line, Bulacu observed that Clifford algebras are weak Hopf algebras in the aforementioned categories and obtained other interesting properties. The aim of this paper is to study generalized Clifford algebras in a similar manner and extend the results of Albuquerque, Majid and Bulacu to the generalized setting. In particular, by taking full advantage of the gauge transformations in symmetric linear Gr-categories, we derive the decomposition theorem and provide categorical weak Hopf structures for generalized Clifford algebras in a conceptual and simpler manner

The role of bone morphogenetic protein 2 in SMA-directed angiogenesis during distraction osteogenesis

Bone is one of the few organs capable of regeneration after a substantial injury. As the bone heals itself after trauma, the coupling of angiogenesis to osteogenesis is crucial for the restoration of the skeletal tissue. In prior studies we have shown that Bone Morphogenetic Protein 2 (BMP2), a potent agonist for skeletal formation is expressed by vessels making it a prime candidate that links the morphogenesis of the two tissues. To investigate the role of BMP2 in the coordination of vessel and bone formation, we used a tamoxifen inducible Smooth Muscle Actin (SMA) promoter that conditionally expresses Cre recombinases crossed with a BMP2 floxed mouse in order to conditionally delete the BMP2 gene in smooth muscle actin (SMA) expressing cells. Using the mouse femur as our model for bone regeneration, we performed a surgical technique called distraction osteogenesis (DO) where an osteotomy is created followed by distraction or a gradual separation of the two pieces of bone. This primarily promotes intramembranous ossification at the osteotomy site by mechanical stimulation. Tamoxifen treatment started at day 6 and continued throughout the experiment. At post-operative days 3, 7, 12, 17, 24, and 31, we analyzed the bone and vessel formation by plain X-ray, micro-computed tomography (µCT) and vascular contrast enhanced µCT, and quantitative polymerase chain reaction (qPCR) of selective genes. We assessed both the femur and surrounding tissue to obtain qualitative and quantitative assessments for skeletal and vascular formation. Our results demonstrated that the deletion of BMP2 in vascular tissue resulted in a reduction of angiogenesis in vivo followed by a decrease in skeletal tissue development