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Energy-efficient power allocation scheme for distributed antenna system over spatially correlated Rayleigh channels

IET COMMUNICATIONS 2018年第5期12卷 533-542页

作者： Xu, Weiye Wen, Benben Lin, Min Yu, Xiangbin Nanjing Inst Technol Sch Commun Engn Nanjing Jiangsu Peoples R China PLA Univ Sci & Technol Coll Commun Engn Nanjing Jiangsu Peoples R China Nanjing Univ Aeronaut & Astronaut Coll Elect & Informat Engn Nanjing Jiangsu Peoples R China Nanjing Inst Telecommun Technol Nanjing Jiangsu Peoples R China

The energy-efficient power allocation (PA) of distributed antenna system using multiple receive antennas is studied over spatially correlated Rayleigh channels. A new energy efficiency (EE) defined as the ratio of the average transmission rate to the consumed total power is presented. According to this definition, subject to the maximum power constraint, an optimal PA scheme is developed by maximising the EE. It is shown that the solution of PA in the constrained EE optimisation does exist and is unique. A Newton method with iterative algorithm is proposed to attain the PA. To avoid iterative calculation of the optimal scheme, a suboptimal PA scheme is derived by means of the Lambert function. As a result, closed-form PA is obtained. The developed schemes only need the statistical channel information and large scale information, and thus they have lower overhead and better robustness. Moreover, they may include the ones over spatially independent channel as special cases. The theoretical EE is further derived for performance evaluation, and the resultant closed-form expression is obtained. Computer simulation indicates that the theoretical EE agrees well the simulation result, and the suboptimal PA scheme can achieve the EE value near to the optimal one with lower complexity.

关键词： optimisation statistical analysis Newton method receiving antennas energy conservation telecommunication power management Rayleigh channels distributed antenna system spatially correlated Rayleigh channels multiple receive antennas average transmission rate optimal PA scheme system EE maximization constrained EE optimisation Newton method iterative algorithm iterative calculation complexity reduction suboptimal PA scheme Lambert function closed-form PA statistical channel information spatially independent channel performance evaluation closed-form theoretical expression computer simulation

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A CT metal artifact reduction algorithm based on sinogram surgery

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JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2018年第3期26卷 413-434页

作者： Jeon, Soomin Lee, Chang-Ock Korea Adv Inst Sci & Technol Dept Math Sci 291 Daehak Ro Daejeon 34141 South Korea

BACKGROUND: Streak artifacts in computed tomography (CT) images caused by metallic objects limit the wider use of CT imaging technologies. There have been various attempts to improve CT images containing streak artifacts;however, most of them generate additional artifacts or do not completely eradicate existing artifacts. OBJECTIVE: In this paper, we propose a novel algorithm which reduces streak artifacts in CT images. METHODS: Using CT numbers reconstructed from a given sinogram, we extract the metal partM and the surrounding area C with similar CT numbers. By filling in the area C. M with the evaluated average CT number of C, we obtain a modified CT image. Using forward projection of the modified CT image, we generate a sinogram containing information about the anatomical structure. We undertake sinogram surgery to remove the metallic effects from the sinogram, after which we repeat the procedure. RESULTS: We perform numerical experiments using various simulated phantoms and patient images. For a quantitative analysis, we use the relative l(infinity) error and the relative l(2) error. In simulated phantom experiments, all l(infinity) errors and l(2) errors approach 10% and1% of the initial errors, respectively. Moreover, for the patient image simulations, all l(infinity) errors are decreased by a factor of 20 while the l(2) errors are decreased less than 5%. We observe that the proposed algorithm effectively reduces the metal artifacts. CONCLUSIONS: In this paper, we propose a metal artifact reduction algorithm based on sinogram surgery to reduce metal artifacts without additional artifacts. We also provide empirical convergence of our algorithm.

关键词： Computed tomography (CT) metal artifact reduction sinogram surgery iterative algorithm

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Multi-Objective Optimization of Hybrid Renewable Energy System Using Reformed Electric System Cascade Analysis for Islanding and Grid Connected Modes of Operation

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IEEE ACCESS 2018年 6卷 47332-47354页

作者： Singh, Ranjay Bansal, Ramesh C. Singh, Arvind R. Naidoo, Raj Univ Pretoria Dept Elect Elect & Comp Engn ZA-0084 Pretoria South Africa

This paper presents a new methodology of reformed electric system cascade analysis (RESCA) for the optimization of hybrid renewable energy system (HRES) with wind energy conversion system, PV system, battery energy storage system, non-intermittent source, and grid as system components. Four different configurations of HRES in islanding and grid-connected mode is considered for analysis. The four configurations of HRES is optimized using RESCA with constraints, such as final excess energy, renewable energy fraction, energy generation ratio, loss of power supply probability, and annual system cost (ASC). The optimization is realized for a residential load in Newark, USA consisting of 100 households with a daily consumption of 30 kWh for each house. The paper successfully presents the application of the RESCA methodology for the optimization of HRES based on reliability and economic constraints for both isolated and grid connected mode of applications.

关键词： Hybrid power systems renewable energy sources wind energy solar energy energy storage optimization methods iterative algorithm

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Energy efficient user association and resource allocation in active array aided HetNets

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IET COMMUNICATIONS 2018年第6期12卷 672-679页

作者： Li, Qing Yang, Qinghai Qin, Meng Kwak, Kyung-Sup Xidian Univ Sch Telecommun Engn Collaborat Innovat Ctr Informat Sensing & Underst State Key Lab ISN 2 Taibainan Lu Xian Shaanxi Peoples R China Inha Univ Grad Sch Informat Technol & Telecommun 253 Yonghyun Dong Incheon South Korea

To enable sustainable wireless networks, though new technologies have been proposed to improve the system spectrum efficiency, the energy efficiency (EE) is also of vital importance due to the increasing users and devices. Active array system (AAS) and heterogeneous networks (HetNets) have been reckoned as an enormous enhancement in spectrum efficiency and EE. In this study, the energy efficient user association and resource allocation problem for preference-aware multicast service in AAS aided HetNets is investigated, formulated as a mixed-integer non-linear fractional programming. By generalised fractional programming theory and Lagrangian dual decomposition, an iterative algorithm is devised to determine user association and resource allocation. Further, an efficient solution is proposed to perform quality of service-guaranteed user association and resource allocation to maximise the EE. Simulation results demonstrate the convergence performance and potential gain of the proposed algorithms in terms of EE.

关键词： energy conservation resource allocation multicast communication nonlinear programming integer programming quality of service cellular radio iterative methods energy efficient user association active array-aided HetNet sustainable wireless networks system spectrum efficiency active array system heterogeneous networks resource allocation problem preference-aware multicast service AAS-aided HetNet spectrum efficiency mixed-integer nonlinear fractional programming generalised fractional programming theory Lagrangian dual decomposition iterative algorithm quality of service-guaranteed user association

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'Buy n times, get one free' loyalty cards: Are they profitable for competing firms? A game theoretic analysis

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EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 2018年第2期265卷 621-630页

作者： Bazargan, Amirhossein Karray, Salma Zolfaghari, Saeed Ryerson Univ 350 Victoria St Toronto ON M5B 2K3 Canada Univ Ontario Inst Technol 2000 Simcoe St North Oshawa ON L1H 7K4 Canada

This paper evaluates whether firms offering loyalty programs (LPs) should choose a restricted redemption policy by imposing a specific number of purchases before customers can redeem their points. Such restriction is commonly offered in form of 'buy n times, get one free' loyalty cards. We develop a multinomial logit model where consumer's utility depends on the value of the product and of the rewards. Using an iterative algorithm, we numerically solve a Nash game for two firms offering loyalty programs. Optimal strategies and profits are obtained for three different scenarios (games): (1) both firms do not restrict redemption;(2) both firms restrict redemption;and (3) only one firm restricts redemption while the other firm does not. Our main findings indicate that each firm's optimal strategies are significantly affected by whether the competitor decides to restrict or not to restrict redemption. "In particular, a firm that restricts reward redemption should offer a higher price if its competitor also restricts redemption. Further, the dominant strategy of the game depends on customers' valuations of time and rewards. For example, when customers highly value time but do not highly value rewards, the dominant strategy for both firms is not to restrict redemption. Alternatively, firms can face a Prisoner dilemma situation leading to unrestricted redemption policy for intermediate levels of customer valuation of both time and rewards. (C) 2017 Elsevier B.V. All rights reserved.

关键词： OR in marketing iterative algorithm Multinomial logit models Loyalty programs Game theory

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L1-Norm Distance Minimization-Based Fast Robust Twin Support Vector k-Plane Clustering

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IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 2018年第9期29卷 4494-4503页

作者： Ye, Qiaolin Zhao, Henghao Li, Zechao Yang, Xubing Gao, Shangbing Yin, Tongming Ye, Ning Nanjing Forestry Univ Coll Informat Sci & Technol Nanjing 210037 Jiangsu Peoples R China Huaiyin Inst Technol Lab Internet Things & Internet Technol Jiangsu Pr Nanjing 223003 Jiangsu Peoples R China Nanjing Univ Sci & Technol Jiangsu Key Lab Image & Video Understanding Socia Nanjing 210094 Jiangsu Peoples R China Nanjing Univ Sci & Technol Coll Comp Sci & Technol Nanjing 210094 Jiangsu Peoples R China Huaiyin Inst Technol Coll Comp Engn Huaian Peoples R China Nanjing Forestry Univ Coll Forestry Nanjing 210037 Jiangsu Peoples R China

Twin support vector clustering (TWSVC) is a recently proposed powerful k-plane clustering method. It, however, is prone to outliers due to the utilization of squared L2-norm distance. Besides, TWSVC is computationally expensive, attributing to the need of solving a series of constrained quadratic programming problems (CQPPs) in learning each clustering plane. To address these problems, this brief first develops a new k-plane clustering method called L1-norm distance minimization-based robust TWSVC by using robust L1-norm distance. To achieve this objective, we propose a novel iterative algorithm. In each iteration of the algorithm, one CQPP is solved. To speed up the computation of TWSVC and simultaneously inherit the merit of robustness, we further propose Fast RTWSVC and design an effective iterative algorithm to optimize it. Only a system of linear equations needs to be computed in each iteration. These characteristics make our methods more powerful and efficient than TWSVC. We also conduct some insightful analysis on the existence of local minimum and the convergence of the proposed algorithms. Theoretical insights and effectiveness of our methods are further supported by promising experimental results.

关键词： iterative algorithm k-plane clustering L1-norm distance linear equations twin support vector clustering (TWSVC)

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A Provenance-Aware Multi-dimensional Reputation System for Online Rating Systems

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ACM TRANSACTIONS ON INTERNET TECHNOLOGY 2018年第4期18卷 1–20页

作者： Rezvani, Mohsen Ignjatovic, Aleksandar Bertion, Elisa Shahrood Univ Technol Fac Comp Engn Shahrood *** Iran Univ New South Wales Sydney NSW Australia Purdue Univ Dept Comp Sci W Lafayette IN 47907 USA UNSW Sydney Sch Comp Sci & Engn Sydney NSW 2052 Australia

Online rating systems are widely accepted as means for quality assessment on the web and users increasingly rely on these systems when deciding to purchase an item online. This makes such rating systems frequent targets of attempted manipulation by posting unfair rating scores. Therefore, providing useful, realistic rating scores as well as detecting unfair behavior are both of very high importance. Existing solutions are mostly majority based, also employing temporal analysis and clustering techniques. However, they are still vulnerable to unfair ratings. They also ignore distances between options, the provenance of information, and different dimensions of cast rating scores while computing aggregate rating scores and trustworthiness of users. In this article, we propose a robust iterative algorithm which leverages information in the profile of users and provenance of information, and which takes into account the distance between options to provide both more robust and informative rating scores for items and trustworthiness of users. We also prove convergence of iterative ranking algorithms under very general assumptions, which are satisfied by the algorithm proposed in this article. We have implemented and tested our rating method using both simulated data as well as four real-world datasets from various applications of reputation systems. The experimental results demonstrate that our model provides realistic rating scores even in the presence of a massive amount of unfair ratings and outperforms the well-known ranking algorithms.

关键词： Reputation system rating provenance iterative algorithm online rating

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Heuristic algorithm for a WIP Projection Problem at Finite Capacity in Semiconductor Manufacturing

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IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING 2018年第1期31卷 62-75页

作者： Mhiri, Emna Mangione, Fabien Jacomino, Mireille Vialletelle, Philippe Lepelletier, Guillaume Univ Grenoble G SCOP CNRS F-38000 Grenoble France STMicroelectronics Ind Engn Dept F-38926 Crolles France STMicroelectronics F-38926 Crolles France

In this paper, we propose a heuristic approach for fixing work-in-progress (WIP) projection issues in the semiconductor industry especially for high mix low volume facilities. The considered problem consists of estimating the start and end dates for each remaining process step of the production lots in the WIP and anticipating the fab loading taking into account the constraints of the maximum throughput of machines considered as capacity constraints and customer delivery commitments. The objective being to guarantee on-time delivery, we focus on minimizing the total weighted tardiness. We have formulated the problem into a mixed-integer programming and we have empirically shown its computational intractability. Due to the computational intractability using actual production data, a heuristic algorithm is proposed. It is an iterative finite capacity planning system that considers as inputs lots due dates and equipment capabilities and capacities. The performance of the heuristic is assessed using industrial instances. It turns out that it achieves targeted objectives with satisfactory results in terms of quality of the solution and computation time.

关键词： WIP projection finite capacity planning semiconductor industry mixed integer programming iterative algorithm

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LAIM: A Linear Time iterative Approach for Efficient Influence Maximization in Large-Scale Networks

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IEEE ACCESS 2018年 6卷 44221-44234页

作者： Wu, Hongchun Shang, Jiaxing Zhou, Shangbo Feng, Yong Qiang, Baohua Xie, Wu Chongqing Univ Coll Comp Sci Chongqing 400044 Peoples R China Chongqing Univ Minist Educ Key Lab Dependable Serv Comp Cyber Phys Soc Chongqing 400044 Peoples R China Guilin Univ Elect Technol Guangxi Cooperat Innovat Ctr Cloud Comp & Big Dat Guilin 541004 Peoples R China Guilin Univ Elect Technol Guangxi Coll & Univ Key Lab Cloud Comp & Complex Guilin 541004 Peoples R China Guilin Univ Elect Technol Guangxi Key Lab Trusted Software Guilin 541004 Peoples R China

The problem of influence maximization (IM) has been extensively studied in recent years and has many practical applications such as social advertising and viral marketing. Given the network and diffusion model, IM aims to find an influential set of seed nodes so that targeting them as diffusion sources will trigger the maximum cascade of influenced individuals. The largest challenge of the IM problem is its NP-hardness, and most of the existing approaches are with polynomial time complexity, making themselves unscalable to very large networks. To address this issue, in this paper, we propose LAIM: a linear time iterative approach for efficient IM on large-scale networks. Our framework has two steps: 1) influence approximation and 2) seed set selection. In the first step, we propose an iterative algorithm to compute the local influence of a node based on a recursive formula and use the local influence to approximate its global influence. In the second step, the k influential seed nodes are mined based on the approximated influence in the first step. Based on our model, we theoretically prove that the proposed approach has linear time and space complexity. We further accelerate our algorithm with simple modifications and propose its fast version. Experimental results on eight real-world large-scale networks exhibit the superiority of our approach over the state-of-the-art methods in terms of both effectiveness and efficiency.

关键词： Influence maximization iterative algorithm social networks analysis information diffusion computational complexity

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Investigation of Large-scale Transmission Tower Grounding Grid with High Amplitude and Uniform Flowing Impulse Current

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JOURNAL OF ELECTRICAL ENGINEERING & TECHNOLOGY 2018年第5期13卷 2050-2058页

作者： Yang, Shuai Huang, Jiarui Wei, Shaodong Zhou, Wenjun Hubei Univ Technol Sch Elect & Elect Engn Wuhan Hubei Peoples R China China Elect Power Res Inst Co Ltd Beijing Peoples R China Wuhan Univ Sch Elect Engn Wuhan Hubei Peoples R China

Impulse characteristic of transmission tower grounding grid is needed for lightning protection of transmission line. This paper describes an outdoor experimental test facility established for large-scale grounding grid of transmission tower, made up of four impulse current generators and a circle current return electrode. The amplitude of impulse current is up to 100 kA. The results of the CDEGS simulation and GPR measurement reveal the uniform current distribution in the test arrangement. An impulse test for a square electrode with extended conductors is carried out in condition of three current waveforms with different amplitude. Based on the electrical network model and iterative algorithm method, a calculation model is proposed to simulate the impulse characteristic of large-scale grounding grid considering soil ionization. The curve of impulse resistance against the current amplitude shows the soil ionization both from the simulation and test. Deviation between the simulation and test result is less than 15%.

关键词： Grounding grid Impulse performance Soil ionization iterative algorithm

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