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PCRM: Increasing POI Recommendation Accuracy in Location-Based Social Networks
( Lianggui Liu ),( Wei Li ),( Lingmin Wang ),( Huiling Jia ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.11
Nowadays with the help of Location-Based Social Networks (LBSNs), users of Point-of-Interest (POI) recommendation service in LBSNs are able to publish their geo-tagged information and physical locations in the form of sign-ups and share their experiences with friends on POI, which can help users to explore new areas and discover new points-of-interest, and promote advertisers to push mobile ads to target users. POI recommendation service in LBSNs is attracting more and more attention from all over the world. Due to the sparsity of users’ activity history data set and the aggregation characteristics of sign-in area, conventional recommendation algorithms usually suffer from low accuracy. To address this problem, this paper proposes a new recommendation algorithm based on a novel Preference-Content-Region Model (PCRM). In this new algorithm, three kinds of information, that is, user's preferences, content of the Point-of-Interest and region of the user’s activity are considered, helping users obtain ideal recommendation service everywhere. We demonstrate that our algorithm is more effective than existing algorithms through extensive experiments based on an open Eventbrite data set.
Bin Xie,Jie Li,Lianggui Liu 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.12
Enhanced Distributed Channel Access (EDCA) mechanism is used in WLAN to support QoS for various multimedia service flows. IEEE 802.11e EDCA introduces some new QoS parameters based on DCF. How to adjust these parameters is a significant problem. In the paper, we present a novel saturated throughput analysis of the IEEE 802.11e EDCA. This approach involves a novel analytical model that is an extension to previous works, which provide Markov chain analysis to IEEE 802.11e EDCA. Throughput analysis of our model is evaluated by comparison with NS2 simulations. We found the model is correct and suitable for both basic access and request-to-send/clear-to-send (RTS/CTS) access mechanisms.
Effective Following Patterns Mining Scheme for the Movements of Objects
Li Chen,Lianggui Liu,Bingxian Chen,Huiling Jia,Yu Zhang 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.6
Technological advances of location aware devices allow us to locate and track the moving objects accurately and in more complex environments. In order to derive valuable knowledge embedded in data from databases, many domestic and foreign scholars have done a lot of work. In this paper, we review the progress of patterns mining mainly in frequent pattern, periodic pattern and following pattern. And we provide a general perspective for studies on different patterns mining by reviewing and comparing the methods and algorithms in detail, providing a quick understanding of research to the worker and giving effective following patterns mining scheme for the movements of objects. The study on patterns mining in movements not only has a direct bearing on human life but also play an important part in environment protection, traffic and transportation, privacy and security and so on. So, the rest of this paper will present these specific applications and analyzed it in theory.
f-CLEAN RINGS AND RINGS HAVING MANY FULL ELEMENTS
Bingjun Li,Lianggui Feng 대한수학회 2010 대한수학회지 Vol.47 No.2
An associative ring R with identity is called a clean ring if every element of R is the sum of a unit and an idempotent. In this paper,we introduce the concept of f-clean rings. We study various properties of f-clean rings. [수식]be a Morita Context ring. We determine conditions under which the ring C is f-clean. Moreover, we introduce the concept of rings having many full elements. We investigate characterizations of this kind of rings and show that rings having many full elements are closed under matrix rings and Morita Context rings.
Morphic property of a quotient ring over polynomial ring
Kai Long,Qichuan Wang,Lianggui Feng 대한수학회 2013 대한수학회보 Vol.50 No.5
A ring R is called left morphic if R/Ra = l(a) for every a 2 R. Equivalently, for every a 2 R there exists b 2 R such that Ra = l(b) and l(a) = Rb. A ring R is called left quasi-morphic if there exist b and c in R such that Ra = l(b) and l(a) = Rc for every a 2 R. A result of T.-K. Lee and Y. Zhou says that R is unit regular if and only if R[x]/(x2) = R / R is morphic. Motivated by this result, we investigate the morphic property of the ring Sn def = R[x1, x2, . . . , xn]/({xixj}), where i, j 2 {1, 2, . . . , n}. The morphic elements of Sn are completely determined when R is strongly regular.
f-CLEAN RINGS AND RINGS HAVING MANY FULL ELEMENTS
Li, Bingjun,Feng, Lianggui Korean Mathematical Society 2010 대한수학회지 Vol.47 No.2
An associative ring R with identity is called a clean ring if every element of R is the sum of a unit and an idempotent. In this paper, we introduce the concept of f-clean rings. We study various properties of f-clean rings. Let C = $\(\array{A\;V\\W\;B}\)$ be a Morita Context ring. We determine conditions under which the ring C is f-clean. Moreover, we introduce the concept of rings having many full elements. We investigate characterizations of this kind of rings and show that rings having many full elements are closed under matrix rings and Morita Context rings.
Research on the Construction of Evaluation Platform for Multimedia Transmission in the Internet
Liang Hu,Li Chen,Lianggui Liu 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.7
All kinds of multimedia data are now transferred via network, which need high level QoS standard because of different compression parameters, network parameters and the status of the network. In this paper, we first discribe relevant parameters and results of the correlation between these parameters by using a novel simulation tool. Usually the factors that affect the transmission of the multimedia in the network generally include: GoP (Group of Picture) pattern, compression quantitative parameters (Quantization Value), the Packet length (Packet Size) and Packet Error Rate (Packet Error Rate). Then, based on the basis of Evalvid and NS2 simulation platform, a new set of tools group are set by integrating these two tools. Video traffic trace file is used to evaluate the network structure in existing research and image quality. Moreover, further study of correlation between these factors and image quality is conducted.
MORPHIC PROPERTY OF A QUOTIENT RING OVER POLYNOMIAL RING
Long, Kai,Wang, Qichuan,Feng, Lianggui Korean Mathematical Society 2013 대한수학회보 Vol.50 No.5
A ring R is called left morphic if $$R/Ra{\simeq_-}l(a)$$ for every $a{\in}R$. Equivalently, for every $a{\in}R$ there exists $b{\in}R$ such that $Ra=l(b)$ and $l(a)=Rb$. A ring R is called left quasi-morphic if there exist $b$ and $c$ in R such that $Ra=l(b)$ and $l(a)=Rc$ for every $a{\in}R$. A result of T.-K. Lee and Y. Zhou says that R is unit regular if and only if $$R[x]/(x^2){\simeq_-}R{\propto}R$$ is morphic. Motivated by this result, we investigate the morphic property of the ring $$S_n=^{def}R[x_1,x_2,{\cdots},x_n]/(\{x_ix_j\})$$, where $i,j{\in}\{1,2,{\cdots},n\}$. The morphic elements of $S_n$ are completely determined when R is strongly regular.