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An improved, randomized algorithm for parallel selection with an experimental study

JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING 2004年第9期64卷 1051-1059页

作者： Bader, DA Univ New Mexico Dept Elect & Comp Engn Albuquerque NM 87131 USA

A common statistical problem is that of finding the median element in a set of data. This paper presents an efficient randomized high-level parallel algorithm for finding the median given a set of elements distributed across a parallel machine. In fact, our algorithm solves the general selection problem that requires the determination of the element of rank k, for an arbitrarily given integer k. Our general framework is an SPMD distributed-memory programming model that is enhanced by a set of communication primitives. We use efficient techniques for distributing and coalescing data as well as efficient combinations of task and data parallelism. The algorithms have been coded in the message-passing standard MPI, and our experimental results from the IBM SP-2 illustrate the scalability and efficiency of our algorithm and improve upon all the related experimental results known to the author. The main contributions of this paper are (1) New techniques for speeding the performance of certain randomized algorithms, such as selection, which are efficient with likely probability. (2) A new, practical randomized selection algorithm (UltraFast) with significantly improved convergence. (C) 2004 Elsevier Inc. All rights reserved.

关键词： selection algorithm randomized algorithms parallel algorithms experimental parallel algorithmics

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Reduced feedback load using user selection algorithms for the multiuser multi-input single-output systems

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TRANSACTIONS ON EMERGING TELECOMMUNICATIONS TECHNOLOGIES 2013年第7-8期24卷 809-819页

作者： Khanfir, Hajer Le Ruyet, Didier Ozbek, Berna Conservatoire Natl Arts & Metiers Elect & Commun Lab F-75141 Paris France Izmir Inst Technol Dept Elect & Elect Engn TR-35430 Izmir Turkey

For wireless multiuser multi-input single-output communication systems with adaptive scheduling and precoding, the users have to feed back their channel state information. However, the amount of feedback data increases with the number of users and the number of transmit antennas. In this paper, we propose a criterion based on the orthogonality between the users' channels to reduce this uplink load. Without cooperation between the users, we only allow users that are semi-orthogonal to feed back their quantized channel information to the base station. We propose a lower bound on the sum rate for the proposed criterion. We show that the performance is almost independent of the number of quantized channel quality information and only channel direction information is important at the transmitter. Then, we consider a noisy feedback channel and propose an algorithm to reduce the noise effect on the analogue *** (c) 2012 John Wiley & Sons, Ltd.

关键词： Channel state information Feedback transmitting antennas orthogonality adaptive scheduling COMMUNICATION SYSTEMS multi-input Quality Information output system algorithms information channels semi-orthogonal selection algorithm Noise effects LOAD

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Efficient multiple antenna-relay selection algorithms for MIMO unidirectional-bidirectional cognitive relay networks

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TRANSACTIONS ON EMERGING TELECOMMUNICATIONS TECHNOLOGIES 2016年第2期27卷 170-183页

作者： Alsharoa, Ahmad Ghazzai, Hakim Alouini, Mohamed-Slim KAUST Comp Elect & Math Sci Engn CEMSE Div Thuwal Makkah Province Saudi Arabia

In this paper, we consider a multiple-input multiple-output (MIMO) cooperative cognitive radio (CR) system using amplify-and-forward protocol under a spectrum sharing scenario, where licensed users and unlicensed users operate on the same frequency band. Indeed, combined CR, cooperative communication and MIMO antennas provide a smart solution for a more efficient usage of the frequency band and the data rate. The main objective of this work is to maximise the sum rate of the unlicensed users allowed to share the spectrum with the licensed users by respecting a tolerated interference threshold under perfect and imperfect channel state information scenarios. Practical approaches based on iterative and genetic algorithms for multiple antenna-relay selections with generalised MIMO model for both unidirectional and bidirectional transmissions are proposed to solve our formulated optimization problems. Interestingly, selected numerical results show that our proposed approaches reach a performance close to the performance of the optimal solution either with discrete or continuous power distributions while providing a considerable saving in terms of computational complexity. Copyright (C) 2014 John Wiley & Sons, Ltd.

关键词： Spectra Relay networks optimal solution Frequency bands multiple input multiple output systems bidirectional transmission Iterative selection algorithm interference threshold

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Recommendations for a standard UK approach to incorporating umbilical cord blood into clinical transplantation practice: conditioning protocols and donor selection algorithms

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BONE MARROW TRANSPLANTATION 2009年第1期44卷 7-12页

作者： Shaw, B. E. Veys, P. Pagliuca, A. Addada, J. Cook, G. Craddock, C. F. Gennery, A. R. Goldman, J. Mackinnon, S. Madrigal, J. A. Marks, D. I. Navarrete, C. Potter, M. N. Querol, S. Regan, F. Russell, N. H. Hough, R. E. Royal Marsden Hosp Dept Blood & Marrow Transplantat Inst Canc Res Sect Haematooncol Sutton SM2 5NG Surrey England Anthony Nolan Trust Res Dept London England Great Ormond St Hosp Sick Children Dept Haematol London England Kings Coll Hosp Dept Haematol London England St James Univ Hosp Dept Haematol Blood & Marrow Transplant Ctr Leeds LS9 7TF W Yorkshire England Queen Elizabeth Hosp Dept Haematol Birmingham W Midlands England Univ Newcastle Dept Pediat Immunol Newcastle Upon Tyne Tyne & Wear England Univ Newcastle BMT Newcastle Upon Tyne Tyne & Wear England Royal Free & Univ Coll Med Sch Sch Med Dept Med London England Bristol Childrens Hosp Dept Haematol Bristol Avon England NHS Blood & Transplant London England UCL Div Infect & Immun London England Nottingham Univ Hosp City Campus Dept Haematol Nottingham England UCLH Children & Young Peoples Canc Serv London England

Allogeneic haematopoietic cell transplantation is an established curative treatment modality for patients with malignant and non-malignant haematological disorders. Since the first related umbilical cord blood transplant (UCBT) in 1988, the use of UCB as a stem cell source for transplantation has become a standard practice in many countries, with approximately 8000 such transplants having been performed worldwide to date. Bone Marrow Transplantation (2009) 44, 7-12;doi:10.1038/bmt.2008.420;published online 12 January 2009

关键词： haematopoietic cell transplantation umbilical cord blood selection algorithm conditioning unrelated donor

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Beyond the USMLE: The STAR algorithm for Initial Residency Applicant Screening and Interview selection

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JOURNAL OF SURGICAL RESEARCH 2019年 235卷 447-452页

作者： Villwock, Jennifer A. Hamill, Chelsea S. Sale, Keith A. Sykes, Kevin J. Univ Kansas Med Ctr Dept Otolaryngol 3901 Rainbow BlvdMailstop 3010 Kansas City KS 66101 USA

Background: Efficient, nonbiased methods for screening residency candidates are lacking. The purpose of this study is to highlight the design, implementation, and impact of the selection Tool for Applicants to Residency (STAR), an objective approach to selecting candidates to interview for residency selection purposes. Materials and methods: Single-institution retrospective cohort study of medical student applicants and current residents of a single otolaryngology residency program from 2008 to 2015 was performed. STAR was introduced to the selection process in 2013 with no USMLE cutoff score needed to receive an interview. Single-institution review of otolaryngology residency program applications from 2008 to 2015 was performed. STAR was introduced in 2013. In addition to applicants, we analyzed characteristics of residents who successfully matched into our program. Prealgorithm residents (n = 16) and postalgorithm residents (n = 12) were compared to assess the impact of this approach on characteristics of successfully matched residents at the program. Results: Three hundred sixty-five applications were analyzed. Applicant pools before and after algorithm displayed similar characteristics. Interestingly, while there was no USMLE "cutoff," scores significantly increased after algorithm. There was no significant difference in the proportion of women (P = 0.588) or underrepresented minorities (P = 0.587) invited to interview pre- and post-STAR. The algorithm significantly decreased the time needed to review applications and interview residency candidates without impacting the overall composition of the interviewee pool. Conclusions: Traditional application review methods can be time consuming and may not ensure effective screening of applicants. STAR, or similar objective tools, may be a viable alternative to evaluate applicants, reduce evaluative time, and potentially decrease the impact of unconscious bias. (C) 2018 Elsevier Inc. All rights reserved.

关键词： Residency application Resident selection selection algorithm Residency education Otolaryngology

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Average minimum transmit power to achieve SINR targets: performance comparison of various user selection algorithms

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2011年第1期2011卷 1页

作者： Salim, Umer Slock, Dirk Intel Mobile Communications Songtao France

In multi-user communication from one base station (BS) to multiple users, the problem of minimizing the transmit power to achieve some target-guaranteed performance (rates) at users has been well investigated in the literature. Similarly, various user selection algorithms have been proposed and analyzed when the BS has to transmit to a subset of the users in the system, mostly for the objective of sum rate maximization. We study the joint problem of minimizing the transmit power at the BS to achieve specific signal-to-interference-and-noise ratio (SINR) targets at users in conjunction with user scheduling. The general analytical results for the average transmit power required to meet guaranteed performance at the users' side are difficult to obtain even without user selection due to joint optimization required over beamforming vectors and power allocation scalars. We study the transmit power minimization problem employing non-linear dirty paper coding (DPC) technique and with various user selection algorithms, namely semi-orthogonal user selection (SUS), norm-based user selection (NUS), and angle-based user selection (AUS). Starting from the derivation of a transmit power upper bound (that becomes tight for large SINR targets), the average minimum transmit power is derived for NUS and SUS, for any number of users. For the special case when only two users are selected, we further derive a similar expression for AUS and a power lower bound, which may serve to benchmark the performance of any selection scheme. Simulation results performed under various settings indicate that SUS is by far the better user selection criterion.

关键词： Bahamas Transmitter power selection algorithm SINR

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Action selection algorithms for autonomous microspacecraft

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1999年第6期22卷 914-916页

作者： Gillies, EA Johnston, AGY McInnes, CR Univ Glasgow Dept Aerosp Engn Glasgow G12 8QQ Lanark Scotland

A scheme for sequencing of tasks on a microspacecraft platform is outlined. The scheme is easily implemented by virtue of its computational simplicity. The strategy is derived from optimal control theory. Action selection with the cue-deficit algorithm is found to perform well on the present microsatellite simulation and to be demonstrably robust to significant failures of the satellite solar array. Robustness to failures of payload, transmitters, and injection into nonoptimum orbits, such as elliptical transfer orbits, rather than the mission orbit, is also demonstrated. (AIAA)

关键词： selection algorithm Satellites Ground Station Optimal Control Earth Attitude Control Depth of Discharge Elliptical Transfer Orbit Reaction Wheels Data Store

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selection of Security Elliptic Curve Based on Evolution algorithm

Selection of Security Elliptic Curve Based on Evolution Algo...

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International Conference on Computational Intelligence and Natural Computing

作者： Wang, Maocai Dai, Guangming Hu, Hanping Pen, Lei Huazhong Univ Sci & Technol Inst Pattern Recognit & Artificial Intelligence Wuhan 430074 Peoples R China China Univ Geosci Sch Comp Wuhan 430074 Peoples R China

ISBN: (纸本)9780769536453

Applying evolution algorithm to selection of security elliptic curve(EC) is first researched in the paper. In order to ensure the security of elliptic curve cryptosystem(ECC), it is necessary that the elliptic curves are safe against all kinds of attack algorithms about the elliptic curve discrete logarithm problem (ECDLP). Therefore, selection of secure elliptic curves is a mathematics difficult problem. In this paper, selection principles of secure EC are firstly analyzed. Then, based on the selection principle, a selection algorithm of security EC based on evolution algorithm is put forward. The thoughts of encoding, crossover and mutation of evolution algorithm for selection of EC are discussed in detail. The implementation result shows the availability and efficiency of the algorithm.

关键词： Elliptic curve selection algorithm ECDLP Evolution algorithm

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Reduced Complexity Joint User and Receive Antenna selection algorithms for SLNR-based Precoding in MU-MIMO Systems

Reduced Complexity Joint User and Receive Antenna Selection ...

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IEEE 75th Vehicular Technology Conference (VTC Spring)

作者： Patcharamaneepakorn, Piya Doufexi, Angela Armour, Simon Univ Bristol CCR Bristol BS8 1TH Avon England

ISBN: (纸本)9781467309905;9781467309882

This paper investigates the user scheduling strategy of multi-user MIMO (MU-MIMO) systems using a transmit precoding scheme based on maximum signal to leakage and noise ratio (SLNR). When users are equipped with multiple antennas, joint user and receive antenna selection may be performed and is shown to potentially provide superior performance to user selection schemes where users utilise all available antennas, especially at high SNR. To overcome the impractical computational burden of exhaustive methods, two suboptimal algorithms are presented in this paper. The simulation results show that the proposed suboptimal algorithms perform very close to the exhaustive joint user and antenna selection algorithm.

关键词： multiple input multiple output systems Receiving antennas selection algorithm prediction coding Simulation results scheduling policy

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A Novel Ant Colony Optimization algorithm for Large Scale QoS-Based Service selection Problem

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DISCRETE DYNAMICS IN NATURE AND SOCIETY 2013年第unknown期2013卷 815193-1-815193-9页

作者： Zhang, Changsheng Yin, Hao Zhang, Bin Northeastern Univ Coll Informat Sci & Engn Shenyang 110819 Peoples R China

To tackle the large scale QoS-based service selection problem, a novel efficient clustering guided ant colony service selection algorithm called CASS is proposed in this paper. In this algorithm, a skyline query process is used to filter the candidates related to each service class, and a clustering based shrinking process is used to guide the ant to the search directions. We evaluate our approach experimentally using standard real datasets and synthetically generated datasets and compared it with the recently proposed related service selection algorithms. It reveals very encouraging results in terms of the quality of solution and the processing time required.

关键词： results service process Ants ant algorithm Dataset 6-chloropenicillanic acid S-sulfoxide Ant colony optimization Query process processing time selection algorithm Legal Services Cluster Analysis

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