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Dynamic Control Cycle Speed Limit Strategy for Improving Traffic Operation at Freeway Bottlenecks
Yaozong Zhang,Minghui Ma,Shidong Liang 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.2
In recent years, variable speed limit (VSL) has been used to decrease the total travel time and alleviate the traffic congestion on freeway. To improve traffic efficiency, we proposed a novel VSL strategy considering dynamic control cycle in this study. An extension of the cell transmission model was used to depict the traffic characteristics under VSL control, and the VSL strategy was designed to provide multiple control cycles. A probability formula was developed and used to determine the optimal quantity of control cycles in the VSL strategy. An objective optimization function was formulated with the aim of minimizing total travel time. A sensitivity analysis was applied to compare different control strategies under a variety of road bottleneck structures by both the numerical analysis and simulation experiments. The results show that dynamic control cycle VSL strategy outperformed other control scenarios and effectively reduced traffic congestion duration and enhanced the service level of freeway network.
The Monetary Exchange Rate Model: Long-run, Short-run, and Forecasting Performance
( Thomas C. Lowinger ),( Shidong Zhang ),( Jie Tang ) 세종대학교 경제통합연구소 (구 세종대학교 국제경제연구소) 2007 Journal of Economic Integration Vol.22 No.2
This paper examines the monetary model of exchange rate determination for the US dollar exchange rates against the currencies of Canada, Japan, and the United Kingdom. In this paper, we utilize the cointegration technique for testing long-run relationship, and vector error correction model for short-run dynamics and out-ofsample forecasting. The existence of cointegration supports the long-run relationship among nominal exchange rate and a number of fundamental variables. The out-ofsample forecasting indicates that the nominal exchange rate forecasts from the VEC monetary model can be superior to random-walk based forecasts in a projection period of less than one year. This conclusion implies that the monetary model of exchange rate determination is a reliable tool for policy makers to evaluate their currency and the monetary authority should expect a much shortened response time to the monetary policy impulse in the surging trend of international economic integration.
Joint Deployment of Small Cells and Wireless Backhaul Links in Next-Generation Networks
Xiangxiang Xu,Saad, Walid,Xiujun Zhang,Xibin Xu,Shidong Zhou IEEE 2015 IEEE communications letters Vol.19 No.12
<P>In this letter, a novel approach for optimizing the joint deployment of small cell base stations and wireless backhaul links is proposed. This joint deployment scenario is cast as a multiobjective optimization problem under the constraints of limited backhaul capacity and outage probability. To address the problem, a novel adaptive algorithm that integrates E-method, Lagrangian relaxation, and tabu search is proposed to obtain the Pareto optimal solution set. Simulation results show that the proposed algorithm is quite effective in finding the optimal solutions. The proposed joint deployment model can be used for planning small cell networks.</P>
A Security Localization Algorithm Based on DV‑Hop Against Sybil Attack in Wireless Sensor Networks
Shi Dong,Xin‑gang Zhang,Wen‑gang Zhou 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.2
Localization technology is crucial in wireless sensor networks (WSN) by forming the basis of various WSN applications. With the advancements of WSN, WSN attacks for node localization have increasingly become an important security issue. The Sybil attack is an example of such attacks where a reputation system is subverted by creating multiple pseudonymous identities. In this paper, a detection and defense algorithm against Sybil attacks based on the distance vector-hop (DV-Hop) method is presented. Experimental results show that the algorithm can efectively improve the security of the node localization in WSN. When the number of beacon nodes is 50, our proposed algorithm reduces the average localization error by 3% than the traditional DV-Hop.
Microblog Sentiment Analysis Method Based on Spectral Clustering
Shi Dong,Xingang Zhang,Ya Li 한국정보처리학회 2018 Journal of information processing systems Vol.14 No.3
This study evaluates the viewpoints of user focus incidents using microblog sentiment analysis, which hasbeen actively researched in academia. Most existing works have adopted traditional supervised machinelearning methods to analyze emotions in microblogs; however, these approaches may not be suitable inChinese due to linguistic differences. This paper proposes a new microblog sentiment analysis method thatmines associated microblog emotions based on a popular microblog through user-building combined withspectral clustering to analyze microblog content. Experimental results for a public microblog benchmarkcorpus show that the proposed method can improve identification accuracy and save manually labeled timecompared to existing methods.