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1,111 results on '"Xu, Lexi"'

225. Survey on 5G Network Expansion Methods

Author

Li, Yi, primary, Jin, Yuchao, additional, Zheng, Yuting, additional, Zhu, Xiaomeng, additional, Cheng, Xinzhou, additional, Li, Fei, additional, Xu, Lexi, additional, and Cao, Lijuan, additional

Published
2021
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243. PoC Testing Analysis of Big Data Products

Author

Cheng Xinzhou, Xu Lexi, Wu Yang, Dong Runsha, and Zhang Ya-Nan

Subjects
Business requirements, Test case, Computer science, Order (business), business.industry, Proof of concept, Business process, Process (engineering), Big data, business, Data science
Abstract

In the era of Big Data, more and more Big Data technologies and Big Data products are emerging. Organization of a Proof of Concept (PoC) testing is important for an enterprise to choose proper Big Data products. This paper introduces typical Big Data vendors and their products, and analyzes the process of preparing a PoC testing. It also illustrates how to design test cases for a PoC testing. In conclusion, it emphasizes that testers should have a deep understanding of business requirements and business processes in order to organize an effective PoC testing program.

Published
2020
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244. An Improved Energy Saving Strategy for SDN-based Data Center

Author

Xu LeXi, Xiao HanLiang, Peng HongYu, Hao TianLu, Wang Kan, and Chen ZhenKai

Subjects
Tree (data structure), Network architecture, Computer science, business.industry, Distributed computing, Decision tree, Data center, Pruning (decision trees), Energy consumption, business, Efficient energy use, Optimal decision
Abstract

With the rapid development of IoT (Internet of Things) technology, the energy consumption problem of IoT data center is getting worse. Based on the fact above, a decision tree based energy optimization strategy CARTS (Classification And Regression Tree based on SDN) is proposed in this paper. The strategy which is based on the Gini index constructs a decision tree from the users' requests' set. Pruning is performed via calculating the penalty factor of the decision tree. Then an optimal decision tree is obtained. Based on this optimal decision tree, CARTS obtains the relationship between users' requests and responses, thereby access efficiency is improved. Efficient access leads to total storage reduction. Energy saving is gained. In addition, the SDN is adopted as the data center's network architecture. The energy saving strategy is easy to be deployed in the SDN controller. Finally, the simulation shows that the energy optimization strategy CARTS proposed in this paper is more energy efficient than the traditional typical energy optimization strategies, and the energy saving ratio is up to 11%.

Published
2020
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245. Research on Energy Dispatching Strategy Based on Energy Forecast Algorithm for Data Center

Author

Xu LeXi, Gong Sha, Xiao HanLiang, and Peng HongYu

Subjects
Computer science, business.industry, Markov process, Energy consumption, Energy minimization, Solar energy, Power (physics), Energy conservation, symbols.namesake, symbols, Data center, business, Algorithm, Energy (signal processing)
Abstract

This paper focuses on energy saving for data center. An energy dispatching strategy EDS (Energy Dispatching Strategy) which is based on energy forecast algorithm PsGMcR (Predicted strategy based on GM (1, 1) and Markov chain Rectify) is proposed. This strategy mainly optimizes data center energy scheduling, reduces carbon emissions, and decreases energy consumption for data center. The architecture of power supply system and data center adopts the SDN architecture. In addition to normal power supply, this strategy adds solar energy to the power supply system. Solar energy adding is able to achieve the purpose of data center energy structure optimization, energy conservation and environmental protection further. Simulation results show that the performance of the proposed strategy is better than other typical energy optimization algorithms, and reducing the carbon emissions of the data center effectively. The energy saving rate is about 12%.

Published
2020
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246. Resource Allocation for RSMA-Based Coordinated Direct and Relay Transmission

Author

Pang, Haoran, Ji, Fei, Xu, Lexi, Liu, Yuan, and Wen, Miaowen

Abstract

In this letter, we investigate a rate splitting multiple access (RSMA) based coordinated direct and relay transmission (CDRT) system, where a base station (BS) serves two users using the rate splitting strategy, and a decode-and-forward (DF) relay aids the BS in establishing a communication link with a far user. We focus on a max-min fairness problem aiming at maximizing the minimum achievable rate of two users. The precoding vectors of the BS and the relay, the common rate of each user and the time allocation coefficients are jointly optimized under the constraint of limited system resources. Unfortunately, the optimization problem is non-convex due to the coupled optimization variables and the non-convex objective. Therefore, we transform the original problem into a difference of convex (DC) program and obtain a sub-optimal solution by adopting an iterative constrained concave convex procedure (CCCP) based algorithm. Simulation results demonstrate substantial performance gains of our proposed RSMA-CDRT over the conventional CDRT strategies and the flexibility in adapting to various channel environments.

Published
2023
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