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Optimal pair matching with two control groups

JOURNAL OF COMPUTATIONAL AND GRAPHICAL STATISTICS 2004年第2期13卷 422-434页

作者： Lu, B Rosenbaum, PR Brown Univ Ctr Stat Sci Providence RI 02912 USA Univ Penn Wharton Sch Dept Stat Philadelphia PA 19104 USA

In an effort to detect hidden biases due to failure to control for an unobserved covariate, some observational or nonrandomized studies include two control groups selected to systematically vary the unobserved covariate. Comparisons of the treated group and two control groups must, of course, control for imbalances in observed covariates. Using the three groups, we form pairs optimally matched for observed covariates-that is, we optimally construct from observational data an incomplete block design. The incomplete block design may use all available data, or it may use data selectively to produce a balanced incomplete block design, or it may be the basis for constructing a matched sample when expensive outcome information is to be collected only for sampled individuals. The problem of optimal pair matching with two control groups is shown by a series of transformations to be equivalent to a particular form of optimal nonbipartite matching, a problem for which polynomial time algorithms exist. In our examples, we implement the procedure using a nonbipartite matching algorithm due to Derigs. We illustrate the method with data from an observational study of the employment effects of the minimum wage.

关键词： assignment algorithm balanced incomplete block design bipartite matching multiple control groups nonbipartite matching observational studies

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Minimum distance matched sampling with fine balance in an observational study of treatment for ovarian cancer

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JOURNAL OF THE AMERICAN STATISTICAL ASSOCIATION 2007年第477期102卷 75-83页

作者： Rosenbaum, Paul R. Ross, Richard N. Silber, Jeffrey H. Univ Penn Wharton Sch Dept Stat Philadelphia PA 19104 USA Childrens Hosp Philadelphia Ctr Outcomes Res Philadelphia PA 19104 USA Univ Penn Sch Med Dept Pediat Philadelphia PA 19104 USA

In observational studies of treatment effects, matched samples have traditionally been constructed using two tools, namely close matches on one or two key covariates and close matches on the propensity score to stochastically balance large numbers of covariates. Here we propose a third tool, fine balance, obtained using the assignment algorithm in a new way. We use all three tools to construct a matched sample for an ongoing study of provider specialty in the treatment of ovarian cancer. Fine balance refers to exact balance of a nominal covariate, often one with many categories, but it does not require individually matched treated and control subjects for this variable. In the example the nominal variable has 72 = 9 x 8 categories formed from 9 possible years of diagnosis and 8 geographic locations or SEER sites. We obtain exact balance on the 72 categories and close individual matches on clinical stage, grade, year of diagnosis, and other variables using a distance, and stochastically balance a total of 61 covariates using a propensity score. Our approach finds an optimal match that minimizes a suitable distance subject to the constraint that fine balance is achieved. This is done by defining a special patterned distance matrix and passing it to a subroutine that solves the optimal assignment problem, which optimally pairs the rows and columns of a matrix using a polynomial time algorithm. In the example we used the function Proc Assign in SAS. A new theorem shows that with our patterned distance matrix, the assignment algorithm returns an optimal, finely balanced matched sample whenever one exists, and otherwise returns an infinite distance, indicating that no such matched sample exists.

关键词： assignment algorithm matched sampling observational study optimal matching propensity score

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LORD: A Moodle Plug-in Helps to Find the Relations Among Learning Objects 18th

LORD: A Moodle Plug-in Helps to Find the Relations Among Lea...

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18th International Conference on Intelligent Tutoring Systems (ITS)

作者： Kuo, Rita Wasowski, Radomir Krahn, Ted Chang, Maiga New Mexico Inst Min & Technol Socorro NM 87801 USA Athabasca Univ Edmonton AB Canada

ISBN: (纸本)9783031096808;9783031096792

Learning Management System (LMS) is widely used in higher education. Researchers have proposed methods to analyze the relations among learning objects (i.e., re-sources/activities) of a course in the LMS and then construct the graph structure for the learning objects. Student's learning behaviour in the LMS can be represented and analysed in graph, i.e., the Learning Object Graph (LOG). With the LOGs represent different students' learning behaviours, plug-in is designed to cluster students into groups based on their learning behaviours. Such method requires the relations among learning objects can be identified and measured accurate and properly. This research explains how the LORD (Learning Object Relation Discovery) Moodle plug-in measures the similarity between two learning objects, with the help ofWordNet and Natural Language Processing, according to their content in English, French and Hindi to create a more reasonable and objective Learning Object Graph (LOG) that can be used to represent students' sequential behaviours among learning objects.

关键词： Behaviour analysis WordNet Semantic similarity Munkre's assignment algorithm Visualization Learning path

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Blockchain Leveraged Task Migration in Body Area Sensor Networks 25

Blockchain Leveraged Task Migration in Body Area Sensor Netw...

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25th Asia-Pacific Conference on Communications (APCC)

作者： Uddin, Md Ashraf Stranieri, Andrew Gondal, Iqbal Balasubramanian, Venki Federat Univ Sch Sci Engn & Informat Technol Internet Commerce Secur Lab Ballarat Vic 3350 Australia

ISBN: (纸本)9781728136790

Blockchain technologies emerging for healthcare support secure health data sharing with greater interoperability among different heterogeneous systems. However, the collection and storage of data generated from Body Area Sensor Networks(BASN) for migration to high processing power computing services requires an efficient BASN architecture. We present a decentralized BASN architecture that involves devices at three levels;1) Body Area Sensor Network- medical sensors typically on or in patient's body transmitting data to a Smartphone, 2) Fog/Edge, and 3) Cloud. We propose that a Patient Agent(PA) replicated on the Smartphone, Fog and Cloud servers processes medical data and execute a task offloading algorithm by leveraging a Blockchain. Performance analysis is conducted to demonstrate the feasibility of the proposed Blockchain leveraged, distributed Patient Agent controlled BASN.

关键词： Internet of Things Task Offload Blockchain Patient Agent Fog/Edge Cloud Body Area Sensor Network assignment algorithm

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Research on Distributed Task Decision-Making Method of UAV Swarm Based on Information Consistency 1

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International Conference on Autonomous Unmanned Systems (ICAUS)

作者： Hou Jun-liang Cui Jin-lei Li Bing Yang Jun-bo Sichuan Aerosp Inst Syst Engn Chengdu 610000 Peoples R China

ISBN: (数字)9789819904792

ISBN: (纸本)9789819904815;9789819904792;9789819904785

Task allocation concerning Unmanned Aerial Vehicle(UAV) swarms, characterized by behavioral self-organization and autonomic decision-making, is a popular term in civil and military areas. At the present time most task allocation algorithms are quadratic or linear, in view of this situation we establishes a new decision-making model with an integer convex optimization based on the distributed task assignment problem of UAV swarms in a confrontation environment. A distributed task event-triggered decision rule is set up, and a distributed optimal task assignment algorithm based on information consistency is proposed. Simulation verification is carried out for the three strike requirements. The results show that the method can achieve global consistency convergence while reducing the communication interaction, obtain targets optimal distribution scheme and satisfy information consistency. The target allocation approach can effectively improve the combat effectiveness of the UAV swarm.

关键词： UAV swarm Decision rules Integer convex optimization Distributed task assignment algorithm

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Multiassignment for tracking a large number of overlapping objects

Multiassignment for tracking a large number of overlapping o...

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Conference on Signal and Data Processing of Small Targets 1997

作者： Kirubarajan, T BarShalom, Y Pattipati, KR Univ. of Connecticut (United States)

ISBN: (纸本)0819425850

In this paper we present a new technique for data association using multiassignment for tracking a large number of closely spaced (and overlapping) objects. The algorithm is illustrated on a biomedical problem, namely the tracking of a group of fibroblast (tissue) cells from an image sequence, which motivated this work. The algorithm presents a novel iterated approach to multiassignnent using successive one-to-one assignments of decreasing size with modified costs. The cost functions, which are adjusted depending on the ''depth'' of the current assignment level and on the tracking results, are derived. The resulting assignments are used to form, maintain and terminate tracks with a modified version of the Probabilistic Data Association Filter, which can handle the contention for a single measurement among multiple tracks in addition to the association of multiple measurements to a single track. Estimation results are given and compared with those of the standard a-dimensional one-to-one assignment algorithm. It is shown that iterated multiassignnent results in superior measurement-to-track association.

关键词： target tracking estimation image tracking closely-spaced targets assignment algorithm multi-assignment Kalman filter probabilistic data association cell tracking bio-medical imaging

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An algorithm for Reducing Leakage Power Based on Dual-threshold Voltage Technique

An Algorithm for Reducing Leakage Power Based on Dual-thresh...

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4th International Conference on Digital Manufacturing and Automation (ICDMA)

作者： Ran Fan Zheng Dandan Yan Xiaolang Zhejiang Univ Inst VLSI Design Hangzhou 310027 Zhejiang Peoples R China

ISBN: (纸本)9780769550169

To reduce the static power of the circuit, a dual-threshold voltage assignment algorithm has been proposed in this paper. This algorithm uses static timing analysis to get the timing information of all nodes by double traverse and assigns the threshold voltage of each node through initial optimization and accurate optimization. Under given timing constraint, the goal of our algorithm is to replace a maximum number of high-Vt gates from low-Vt in the circuit and maximize the reduction of the static power. Our dual-threshold voltage assignment algorithm and traditional method are compared based on the embedded CPU CK610 of TSMC 55nm process. The results show that our algorithm can reduce the static power of the chip by 60.07%.

关键词： dual-threshold voltage assignment algorithm static power static timing analysis

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A Laser Based Multi-Target Tracking for Mobile Robot

A Laser Based Multi-Target Tracking for Mobile Robot

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9th International Conference on Intelligent Autonomous Systems (IAS-9)

作者： Hashimoto, Masafumi Ogata, Satoshi Oba, Fuminori Murayama, Takeshi Doshisha Univ Fac Engn Dept Informat Syst Design Kyoto 6100321 Japan

ISBN: (纸本)9781586035952

This paper presents a method for tracking multiple moving objects with in-vehicle 2D laser range sensor (LRS) in a cluttered environment, where ambiguous/false measurements appear in the laser image due to observing clutters and windows, etc. Moving objects are detected from the laser image with the LRS via a heuristic rule and an occupancy grid based method. The moving objects are tracked based on Kalman filter and the assignment algorithm. A rule based track management system is embedded into the tracking system in order to improve the tracking performance. The experimental results of two people tracking validate the proposed method.

关键词： Mobile robot Laser range sensor Multi-target tracking Occupancy grid method Kalman filter Data association assignment algorithm

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New heuristics for assigning in the Multi-Depot Vehicle Routing Problem 10th

New heuristics for assigning in the Multi-Depot Vehicle Rout...

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10th IFAC Triennial Conference on Manufacturing Modelling, Management and Control (MIM)

作者： Torres-Perez, Isis Rosete, Alejandro Sosa-Gomez, Guillermo Rojas, Omar Univ Tecnol La Habana Jose Antonio Echeverria Cuj Havana Cuba Univ Panamer Fac Ciencias Econ & Empresariales Alvaro del Portillo 49 Zapopan 45010 Jalisco Mexico Univ Airlangga Fac Econ & Business Surabaya Indonesia

The paper addresses the Multi-Depot Vehicle Routing Problem (MDVRP) motivated by its practical relevance and considerable difficulty. Specifically, the work focuses on the assignment of customers to depots, one of the phases carried out to solve the MDVRP. Many authors have tackled this problem, and there are different heuristics to perform this task. This paper presents two new heuristics for this important phase of the MDVRP. Both heuristics are simple to implement and are fast in their execution. Furthermore, experimental results showed that the achieved solutions are comparable to those of some of the most important heuristics for this task. Copyright (C) 2022 The Authors.

关键词： multi-depot vehicle routing problem assignment algorithm optimization transportation logistics

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Clock Skew Minimization with Adjustable Delay Buffers Restriction

Clock Skew Minimization with Adjustable Delay Buffers Restri...

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IEEE 2nd International Symposium on Next-Generation Electronics (ISNE)

作者： Kao, Chi-Chou Lin, Kun-Cte Natl Univ Tainan Dept Comp Sci & Informat Engn Tainan Taiwan Natl Univ Tainan Dept Elect Engn Tainan Taiwan

ISBN: (纸本)9781467330374;9781467330367

Multiple dynamic supply voltage (MDSV) designs can be used to reduce power consumption. However, switching of power modes may cause increasing of the clock skew because some modules operate with different voltages. In this paper, the adjustable delay buffers (ADBs) is used to minimize clock skew under different power modes. We first construct a clock tree to assign positions of adjustable delay buffers. Because adjustable delay buffers can increase additional delays, the clock skew can be optimized. It is unlikely to add an unlimited number of ADBs in real world so the number of ADBs must be limited. If the number of ADBs is not satisfied with the constraints in the previous solution, a bottom-up method is then used to remove some adjustable delay buffers. Finally, the experimental results show that the presented algorithms generate effective improvements.

关键词： adjustable delay buffers clock skew source assignment algorithm minimization

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