Abnormal Group User Detection in Recommender Systems Using Multi-dimension Time Series

2017 ◽  
pp. 373-383 ◽  
Author(s):  
Wei Zhou ◽  
Junhao Wen ◽  
Qingyu Xiong ◽  
Jun Zeng ◽  
Ling Liu ◽  
...  
Keyword(s):  
Time Series ◽  
Recommender Systems ◽  
Abnormal Group

Intelligent POIs Recommender System Based on Time Series Analysis with Seasonal Adjustment

2021 ◽  
Vol 2 (2) ◽  
pp. 66-80
Author(s):  
Meng-Kuan Chen ◽  
Hsin-Wen Wei ◽  
Wei-Tsong Lee
Keyword(s):  
Time Series ◽  
Recommender Systems ◽  
Recommender System ◽  
Research Articles ◽  
Seasonal Adjustment ◽  
Huge Amount ◽  
Travel Information ◽  
Seasonal Factor ◽  
Correct Location ◽  
Travel Recommendation

Recommender systems have been applied on a variety of applications including movies, music, news, books, research articles, search queries, and travel information. Instead of searching travel information from the extremely huge amount of travel data, a personalized travel recommender system is desired. However, an inappropriate travel recommendation may result from a wrong season, even if it is already a correct location. The current recommender systems from time to time make an inappropriate commendation without considering the seasonal factor. In order to resolve the discrepancy, the seasonal factor should have been taken into consideration when making a good travel recommender system. Therefore, this study has taken the trend analysis, time series, and seasonal factor into considerations to cope with the above mentioned discrepancy and to make the travel recommender system renders a better fit.

scholarly journals Shilling attack detection for recommender systems based on credibility of group users and rating time series

PLoS ONE ◽  
2018 ◽  
Vol 13 (5) ◽  
pp. e0196533 ◽  
Author(s):  
Wei Zhou ◽  
Junhao Wen ◽  
Qiang Qu ◽  
Jun Zeng ◽  
Tian Cheng
Keyword(s):  
Time Series ◽  
Recommender Systems ◽  
Attack Detection ◽  
Shilling Attack ◽  
Shilling Attack Detection

scholarly journals Abnormal Profiles Detection Based on Time Series and Target Item Analysis for Recommender Systems

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Wei Zhou ◽  
Junhao Wen ◽  
Min Gao ◽  
Haijun Ren ◽  
Peng Li
Keyword(s):  
Time Series ◽  
Collaborative Filtering ◽  
Recommender Systems ◽  
Target Item ◽  
Item Analysis ◽  
Work Related ◽  
Shilling Attack ◽  
Short Period ◽  
Group Attributes ◽  
Statistical Metrics

Collaborative filtering (CF) recommenders are vulnerable to shilling attacks designed to affect predictions because of financial reasons. Previous work related to robustness of recommender systems has focused on detecting profiles. Most approaches focus on profile classification but ignore the group attributes among shilling attack profiles. Attack profiles are injected in a short period in order to push or nuke a specific target item. In this paper, we propose a method for detecting suspicious ratings by constructing a time series. We reorganize all ratings on each item sorted by time series. Each time series is examined and suspected rating segments are checked. Then we use techniques we have studied in previous study to detect shilling attacks in these anomaly rating segments using statistical metrics and target item analysis. We show in experiments that our proposed method can be effective and less time consuming at detecting items under attacks in big datasets.

scholarly journals Item Anomaly Detection Based on Dynamic Partition for Time Series in Recommender Systems

PLoS ONE ◽  
2015 ◽  
Vol 10 (8) ◽  
pp. e0135155 ◽  
Author(s):  
Min Gao ◽  
Renli Tian ◽  
Junhao Wen ◽  
Qingyu Xiong ◽  
Bin Ling ◽  
...  
Keyword(s):  
Time Series ◽  
Anomaly Detection ◽  
Recommender Systems

The LDE-Type Flare Occurrence (1969-1993)

1994 ◽  
Vol 144 ◽  
pp. 279-282
Author(s):  
A. Antalová
Keyword(s):  
Time Series ◽  
Fourier Analysis ◽  
Sunspot Cycle ◽  
List Type ◽  
Type Number ◽  
Solar Cycles ◽  
Type Iv ◽  
Long Duration ◽  
Cycle Maximum ◽  
Flare Index

AbstractThe occurrence of LDE-type flares in the last three cycles has been investigated. The Fourier analysis spectrum was calculated for the time series of the LDE-type flare occurrence during the 20-th, the 21-st and the rising part of the 22-nd cycle. LDE-type flares (Long Duration Events in SXR) are associated with the interplanetary protons (SEP and STIP as well), energized coronal archs and radio type IV emission. Generally, in all the cycles considered, LDE-type flares mainly originated during a 6-year interval of the respective cycle (2 years before and 4 years after the sunspot cycle maximum). The following significant periodicities were found:• in the 20-th cycle: 1.4, 2.1, 2.9, 4.0, 10.7 and 54.2 of month,• in the 21-st cycle: 1.2, 1.6, 2.8, 4.9, 7.8 and 44.5 of month,• in the 22-nd cycle, till March 1992: 1.4, 1.8, 2.4, 7.2, 8.7, 11.8 and 29.1 of month,• in all interval (1969-1992):a)the longer periodicities: 232.1, 121.1 (the dominant at 10.1 of year), 80.7, 61.9 and 25.6 of month,b)the shorter periodicities: 4.7, 5.0, 6.8, 7.9, 9.1, 15.8 and 20.4 of month.Fourier analysis of the LDE-type flare index (FI) yields significant peaks at 2.3 - 2.9 months and 4.2 - 4.9 months. These short periodicities correspond remarkably in the all three last solar cycles. The larger periodicities are different in respective cycles.

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