Keyword-aware Optimal Route Search

Identifying a preferable route is an important problem that finds applications in map services. When a user plans a trip within a city, the user may want to find "a most popular route such that it passes by shopping mall, restaurant, and pub, and the travel time to and from his hotel is within 4 hours." However, none of the algorithms in the existing work on route planning can be used to answer such queries. Motivated by this, we define the problem of keyword-aware optimal route query, denoted by KOR, which is to find an optimal route such that it covers a set of user-specified keywords, a specified budget constraint is satisfied, and an objective score of the route is optimal. The problem of answering KOR queries is NP-hard. We devise an approximation algorithm OSScaling with provable approximation bounds. Based on this algorithm, another more efficient approximation algorithm BucketBound is proposed. We also design a greedy approximation algorithm. Results of empirical studies show that all the proposed algorithms are capable of answering KOR queries efficiently, while the BucketBound and Greedy algorithms run faster. The empirical studies also offer insight into the accuracy of the proposed algorithms.Comment: VLDB201

Location- and keyword-based querying of geo-textual data: a survey

With the broad adoption of mobile devices, notably smartphones, keyword-based search for content has seen increasing use by mobile users, who are often interested in content related to their geographical location. We have also witnessed a proliferation of geo-textual content that encompasses both textual and geographical information. Examples include geo-tagged microblog posts, yellow pages, and web pages related to entities with physical locations. Over the past decade, substantial research has been conducted on integrating location into keyword-based querying of geo-textual content in settings where the underlying data is assumed to be either relatively static or is assumed to stream into a system that maintains a set of continuous queries. This paper offers a survey of both the research problems studied and the solutions proposed in these two settings. As such, it aims to offer the reader a first understanding of key concepts and techniques, and it serves as an “index” for researchers who are interested in exploring the concepts and techniques underlying proposed solutions to the querying of geo-textual data.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)Nanyang Technological UniversityThis research was supported in part by MOE Tier-2 Grant MOE2019-T2-2-181, MOE Tier-1 Grant RG114/19, an NTU ACE Grant, and the Singtel Cognitive and Artificial Intelligence Lab for Enterprises (SCALE@NTU), which is a collaboration between Singapore Telecommunications Limited (Singtel) and Nanyang Technological University (NTU) that is funded by the Singapore Government through the Industry Alignment Fund Industry Collaboration Projects Grant, and by the Innovation Fund Denmark centre, DIREC

Unification of gravity, gauge fields, and Higgs bosons

We consider a diffeomorphism invariant theory of a gauge field valued in a Lie algebra that breaks spontaneously to the direct sum of the spacetime Lorentz algebra, a Yang-Mills algebra, and their complement. Beginning with a fully gauge invariant action -- an extension of the Plebanski action for general relativity -- we recover the action for gravity, Yang-Mills, and Higgs fields. The low-energy coupling constants, obtained after symmetry breaking, are all functions of the single parameter present in the initial action and the vacuum expectation value of the Higgs.Comment: 12 pages, no figures. v2 minor correction

Parallel trajectory similarity joins in spatial networks

2018 Springer-Verlag GmbH Germany, part of Springer Nature The matching of similar pairs of objects, called similarity join, is fundamental functionality in data management. We consider two cases of trajectory similarity joins (TS-Joins), including a threshold-based join (Tb-TS-Join) and a top-k TS-Join (k-TS-Join), where the objects are trajectories of vehicles moving in road networks. Given two sets of trajectories and a threshold (Formula presented.), the Tb-TS-Join returns all pairs of trajectories from the two sets with similarity above (Formula presented.). In contrast, the k-TS-Join does not take a threshold as a parameter, and it returns the top-k most similar trajectory pairs from the two sets. The TS-Joins target diverse applications such as trajectory near-duplicate detection, data cleaning, ridesharing recommendation, and traffic congestion prediction. With these applications in mind, we provide purposeful definitions of similarity. To enable efficient processing of the TS-Joins on large sets of trajectories, we develop search space pruning techniques and enable use of the parallel processing capabilities of modern processors. Specifically, we present a two-phase divide-and-conquer search framework that lays the foundation for the algorithms for the Tb-TS-Join and the k-TS-Join that rely on different pruning techniques to achieve efficiency. For each trajectory, the algorithms first find similar trajectories. Then they merge the results to obtain the final result. The algorithms for the two joins exploit different upper and lower bounds on the spatiotemporal trajectory similarity and different heuristic scheduling strategies for search space pruning. Their per-trajectory searches are independent of each other and can be performed in parallel, and the mergings have constant cost. An empirical study with real data offers insight in the performance of the algorithms and demonstrates that they are capable of outperforming well-designed baseline algorithms by an order of magnitude

OR-011 Effect of Aerobic and Resistance Exercise on TGF-β1/Smad3 Signal Pathway and Collagen in Skeletal Muscle of Aging Mice

Objective The purpose of this study was to investigate the effects of TGF-β 1/Smad3  signaling pathway and its downstream factor CTGF in collagen deposition and its molecular mechanism. And then it explored further the effect of exercise on the TGF-β1/Smad3 signaling pathway and collagen deposition in skeletal muscle. Therefore, it is expected to provide alternative exercise intervention approaches for skeletal muscle diseases, which are caused by age-related changes of collagen, and to provide new research perspectives for skeletal muscle satellite cell activation and skeletal muscle regeneration. Methods 21 male BALB/c mice were normally raised from 4 weeks to 36 weeks under standard conditions. The mice was divided randomly into three groups, including: group C, the quiet control group; Group A, the aerobics training group, received nine weeks of treadmill training without loading; And the group R, the resistance training group, received nine weeks of climbing training with loading. The body weight and limb grip of the mice were measured on regularly during the experiment. After 24 hours of the last intervention experiment, the mice were weighed and then executed by dislocating the cervical spine. The quadriceps were taken. Real-time PCR technology was used to detect the mRNA levels of TGF-β1, TβR I, Smad 3, CTGF, Pax7, COL1 and COL3. Western blotting technique was used to detect the protein levels of TGF-β1, Smad3, P-Smad3 , CTGF, COL1, COL3, Pax7 and MyoD . The deposition of collagen in the quadriceps muscle tissue of mice was detected by Sirius red staining. And the localization and expressions of COL1 and Pax7 in the quadriceps of mice were demonstrated by immunohistochemistry and immunofluorescence technology respectively. Results (1)       Compared with group C, the weight of mice in group A was significantly increased (P<0.05), and the ratio of the wet weight of the quadriceps and the body weight of the mice increased significantly (P<0.05), while there was no significant change on the limbs relative grip strength. Compared with group C, the body weight of mice in group R showed a certain degree of increase but no significant difference, the ratio between the wet weight of the quadriceps and the body weight of the mice was significantly increased (P<0.01), and the limbs relative grip strength was significantly increased (P<0.05). (2)     Compared with group C, there was no significant difference in the mRNA and protein expression of COL1 and COL3 in the quadriceps of mice in group A, and there was no significant change in collagen volume fraction. Compared with group C, the mRNA and protein expression of COL1 and COL3 of the quadriceps in group R were significantly decreased (P<0.05), and collagen volume fraction significantly reduced (P<0.05), and collagen deposition decreased. (3)     Compared with group C, the mRNA level of CTGF and the protein level of TGF-β1 and CTGF in quadriceps tissues of mice in group A were significantly decreased (P<0.05). While the protein levels of Smad3 and p-Smad3 and the ratio of Smad3 and p-Smad3 had no significant change. Group R is compared with group C, the mRNA level of TGF-β1, TβR I and CTGF in quadriceps were significantly decreased (P<0.05); the mRNA levels of Smad3 and the protein levels of TGF-β1 and p-Smad3 were significantly decreased (P<0.01); and the protein levels of Smad3 and CTGF and the ratio of Smad3 and p-Smad3 were also significantly decreased (P<0.05). (4)     Compared with group C, the mRNA and protein expression of Pax7, and the protein expression of MyoD in the quadriceps of group A showed no significant difference. But group R is compared to group C, the expression of Pax7 mRNA in the quadriceps was significantly increased (P<0.01), and the expression of Pax7 protein was also significantly increased (P<0.05), while the protein expression of MyoD did not change significantly. Compared with group A, the mRNA levels of Pax7 in the quadriceps of the R group was significantly increased (P<0.05), but the protein expression of Pax7 and MyoD showed no significant change. Conclusions (1)     Through 9 week resistance or aerobic exercise training, skeletal muscle mass index in mice increased significantly; and the resistance exercise training can improve the limbs relative grip strength to prevent sacorpenia. (2)     9 week resistance exercise training can inhibit TGF-β1/Smad3 signaling pathway, affect the gene expression of COL1 and COL3, inhibit collagen synthesis, and improve collagen deposition. (3)     9 weeks of resistance exercise training can effectively promote Pax7 gene expression, activate skeletal muscle satellite cells and promote its proliferation. (4)     The effect of 9 week of resistance exercise training on the improvement of skeletal muscle mass, strength, collagen deposition and the activation of satellite cells was significantly better than that of aerobic exercise