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Multiconstrained Finite-Horizon Piecewise Deterministic Markov Decision Processes with Unbounded Transition Rates

MATHEMATICS OF OPERATIONS RESEARCH 2020年第2期45卷 641-659页

作者： Huang, Yonghui Guo, Xianping Sun Yat Sen Univ Sch Math Guangzhou 510275 Guangdong Peoples R China

This paper studies a multiconstrained problem for piecewise deterministic Markov decision processes (PDMDPs) with unbounded cost and transition rates. The goal is to minimize one type of expected finite-horizon cost over history-dependent policies while keeping some other types of expected finite-horizon costs lower than some tolerable bounds. Using the Dynkin formula for the PDMDPs, we obtain an equivalent characterization of occupancy measures and express the expected finite-horizon costs in terms of occupancy measures. Under suitable assumptions, the existence of constrained-optimal policies is shown, the linear programming formulation and its dual program for the constrained problem are derived, and the strong duality between the two programs is established. An example is provided to demonstrate our results.

关键词： piecewise deterministic Markov decision process finite horizon constrained problem occupancy measure linear program

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Optimization model for combining drug vials in the preparation of doses for outpatient

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OPERATIONS RESEARCH FOR HEALTH CARE 2023年 38卷

作者： Ge, Maria Clara de Oliveira do Carmo, Breno Barros Telles Fontes, Fabio Francisco da Costa Aloise, Dario Jose Univ Fed Pernambuco Dept Prod Engn Av Arquitetura S-N BR-50740550 Recife PE Brazil Univ Fed Ceara Ind Engn Dept Campus PiciBloco 735 BR-60440900 Fortaleza CE Brazil Univ Fed Rural Semi Arido Dept Comp Sci Ave Francisco Mota 572 BR-59625900 Mossoro RN Brazil Univ Estado Rio Grande do Norte Dept Informat Rua Almino Afonso 478 BR-59610210 Mossoro RN Brazil

Planning the use of chemotherapy drugs in outpatient treatment is a complex problem due to the variability of cancer, resulting in different chemotherapy protocols. This process involves factors such as the cyclical nature of treatment protocols and clinical resources. Within this context, an optimization model is needed to plan the use of chemotherapy drugs in the preparation of doses for patient treatment, considering the operational particularities of treatment centers. This study proposed a linear programming model based on the multiple knapsack problem, in order to optimize the combination of different vials of chemotherapy drugs, minimizing the total cost of treatment. The model, based on the daily schedule of patients, provides the best combination of drug vials and supports the preparation process of each dose prescribed by the doctor for each patient, respecting the treatment protocol and resource limitations. The model was implemented in the CPLEX 12.9.0 application, and the computational tests were performed with real data. The results demonstrated that the costs when applying the model were 5% lower when compared to the current manner in which the oncology pharmacy combines the drugs vials.

关键词： Chemotherapy drugs Outpatient chemotherapy linear program Multiple knapsack problem

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On Max-Min Throughput in Backscatter-Assisted Wirelessly Powered IoT

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IEEE INTERNET OF THINGS JOURNAL 2020年第1期7卷 137-147页

作者： Yang, Changlin Wang, Xiaodong Chin, Kwan-Wu Zhongyuan Univ Technol Sch Comp Sci Zhengzhou 450007 Peoples R China Columbia Univ Elect Engn Dept New York NY 10027 USA Univ Wollongong Sch Elect Comp & Telecommun Engn Wollongong NSW 2522 Australia

Backscatter communication can potentially find wide Internet of Things (IoT) applications because of its negligible energy consumption. Traditional backscatter communication relies on either dedicated radio-frequency (RF) sources, such as RF identification readers and power beacons, or ambient RF sources, e.g., TV and cellular signals. In this article, we study a backscatter-assisted wirelessly powered IoT system where devices can backscatter when nearby devices are actively transmitting via RF. Our objective is to determine the transmission schedule for all devices that maximizes the minimum system throughput. We formulate such a scheduling problem as a linear program for both linear and random networks. A key step in the formulation is to identify the groups of devices that can simultaneously backscatter without causing interference. Simulation results show that the max-min system throughput in linear and random networks can be increased by 46 and 180 times, respectively, by using the proposed backscatter-assisted schedule as compared with the traditional time-division multiple access (TDMA).

关键词： Backscatter Radio frequency Internet of Things Throughput RF signals Time division multiple access TV Backscatter communication Internet of Things (IoT) linear program max-min throughput transmission scheduling

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Fractional matching preclusion number of graphs and the perfect matching polytope

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JOURNAL OF COMBINATORIAL OPTIMIZATION 2020年第3期39卷 915-932页

作者： Lin, Ruizhi Zhang, Heping Lanzhou Univ Sch Math & Stat Lanzhou 730000 Gansu Peoples R China Fujian Univ Technol Sch Math & Phys Fuzhou 350118 Fujian Peoples R China

Let G be a graph with an even number of vertices. The matching preclusion number of G, denoted by mp(G), is the minimum number of edges whose deletion leaves the resulting graph without a perfect matching. We introduced a 0-1 linear program which can be used to find the matching preclusion number of graphs. In this paper, by relaxing of the 0-1 linear program we obtain a linear program and call its optimal objective value as fractional matching preclusion number of graph G, denoted by mpf (G). We showmpf (G) can be computed in polynomial time for any graph G. By using the perfect matching polytope, we transform it into a new linear program whose optimal value equals the reciprocal of mpf (G). For bipartite graph G, we obtain an explicit formula for mpf (G) and show that mpf (G) is the maximum integer k such that G has a k-factor. Moreover, for any two bipartite graphs G and H, we show mpf (G H) mpf (G) + mpf (H), where G H is the Cartesian product of G and H.

关键词： Graph Perfect matching Matching preclusion linear program Perfect matching polytope Flow

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A comparison of computational driver models using naturalistic and test-track data from cyclist-overtaking manoeuvres

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TRANSPORTATION RESEARCH PART F-TRAFFIC PSYCHOLOGY AND BEHAVIOUR 2020年 75卷 87-105页

作者： Kovaceva, Jordanka Bargman, Jonas Dozza, Marco Chalmers Univ Technol Gothenburg Sweden

The improvement of advanced driver assistance systems (ADAS) and their safety assessment rely on the understanding of scenario-dependent driving behaviours, such as steering to avoid collisions. This study compares driver models that predict when a driver starts steering away to overtake a cyclist on rural roads. The comparison is among four models: a threshold model, an accumulator model, and two models inspired by a proportional-integral and proportional-integral-derivative controller. These models were tested and cross-applied using two different datasets: one from a naturalistic driving (ND) study and one from a test-track (TT) experiment. Two perceptual variables, expansion rate (the horizontal angular expansion rate of the image of the lead road user on the driver's retina) and inverse tau (the ratio between the image's expansion rate and its horizontal optical size), were tested as input to the models. A linear cost function is proposed that can obtain the optimal parameters of the models by computationally efficient linear programming. The results show that the models based on inverse tau fitted the data better than the models that included expansion rate. In general, the models fitted the ND data reasonably well, but not as well the TT data. For the ND data, the models including an accumulative component outperformed the threshold model. For the TT data, due to the poorer fit of the models, more analysis is required to determine the merit of the models. The models fitted to TT data captured the overall pattern of steering onsets in the ND data rather well, but with a persistent bias, probably due to the drivers employing a more cautious strategy in TT. The models compared in this paper may support the virtual safety assessment of ADAS so that driver behaviour may be considered in the design and evaluation of new safety systems. (C) 2020 The Author(s). Published by Elsevier Ltd.

关键词： Driver behaviour Overtaking Cyclist Driver modelling linear program

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A linear program Formulation for the Segmentation of Ciona Membrane Volumes

A Linear Program Formulation for the Segmentation of <i>Cion...

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16th International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI)

作者： Delibaltov, Diana L. Ghosh, Pratim Rodoplu, Volkan Veeman, Michael Smith, William Manjunath, B. S. Univ Calif Santa Barbara Dept Elect & Comp Engn Santa Barbara CA 93106 USA Univ Calif Santa Barbara Dept Mol Cellular & Dev Santa Barbara CA 93106 USA Kansas State Univ Div Biol Manhattan KS 66506 USA

ISBN: (纸本)9783642408113;9783642408106

We address the problem of cell segmentation in confocal microscopy membrane volumes of the ascidian Ciona used in the study of morphogenesis. The primary challenges are non-uniform and patchy membrane staining and faint spurious boundaries from other organelles (e.g. nuclei). Traditional segmentation methods incorrectly attach to faint boundaries producing spurious edges. To address this problem, we propose a linear optimization framework for the joint correction of multiple over-segmentations obtained from different methods. The main idea motivating this approach is that multiple over-segmentations, resulting from a pool of methods with various parameters, are likely to agree on the correct segment boundaries, while spurious boundaries are method- or parameter-dependent. The challenge is to make an optimized decision on selecting the correct boundaries while discarding the spurious ones. The proposed unsupervised method achieves better performance than state of the art methods for cell segmentation from membrane images.

关键词： Cell segmentation linear program Joint segmentation

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Bipartite Matching in Nearly-linear Time on Moderately Dense Graphs 61

Bipartite Matching in Nearly-linear Time on Moderately Dense...

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61st IEEE Annual Symposium on Foundations of Computer Science (FOCS)

作者： van den Brand, Jan Lee, Yin-Tat Nanongkai, Danupon Peng, Richard Saranurak, Thatchaphol Sidford, Aaron Song, Zhao Wang, Di KTH Royal Inst Technol Stockholm Sweden Univ Washington Seattle WA 98195 USA Microsoft Res Redmond Redmond WA USA Georgia Inst Technol Atlanta GA 30332 USA Toyota Technol Inst Chicago Chicago IL USA Stanford Univ Stanford CA 94305 USA Columbia Univ New York NY 10027 USA Princeton Univ Princeton NJ 08544 USA Inst Adv Study Olden Lane Princeton NJ 08540 USA Google Res Cambridge MA USA

ISBN: (纸本)9781728196213

We present an (O) over tilde (m + n(1.5))-time randomized algorithm for maximum cardinality bipartite matching and related problems (e.g. transshipment, negative-weight shortest paths, and optimal transport) on m-edge, n-node graphs. For maximum cardinality bipartite matching on moderately dense graphs, i.e. m = Omega(n(1.5)), our algorithm runs in time nearly linear in the input size and constitutes the first improvement over the classic O(m root n)-time [Dinic 1970;HopcroftKarp 1971;Karzanov 1973] and (O) over tilde (n(omega))-time algorithms [Ibarra-Moran 1981] (where currently omega approximate to 2.373). On sparser graphs, i.e. when m = n(9/8+delta) for any constant delta > 0, our result improves upon the recent advances of [Madry 2013] and [Liu-Sidford 2020b, 2020a] which achieve an (O) over tilde (m(4/3+o)(1)) runtime. We obtain these results by combining and advancing recent lines of research in interior point methods (IPMs) and dynamic graph algorithms. First, we simplify and improve the IPM of [***-LeeSidford-Song 2020], providing a general primal-dual IPM framework and new sampling-based techniques for handling infeasibility induced by approximate linear system solvers. Second, we provide a simple sublinear-time algorithm for detecting and sampling high-energy edges in electric flows on expanders and show that when combined with recent advances in dynamic expander decompositions, this yields efficient data structures for maintaining the iterates of both [*** et al.] and our new IPMs. Combining this general machinery yields a simpler (O) over tilde (n root m) time algorithm for matching based on the logarithmic barrier function, and our state-of-the-art (O) over tilde (m + n(1.5)) time algorithm for matching based on the [Lee-Sidford 2014] barrier (as regularized in [*** et al.]).

关键词： bipartite matching shortest paths transshipment optimal transport nearly linear time interior point method linear program

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Improved Optimization Design of Degree Distributions in Fountain Codes

Improved Optimization Design of Degree Distributions in Foun...

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IEEE International Conference on Artificial Intelligence and Information Systems (ICAIIS)

作者： Xu, Shengkai Xu, Dazhuan Nanjing Univ Aeronaut & Astronaut Coll Elect & Informat Engn Jiangsu Key Lab Internet Things & Control Technol Nanjing Peoples R China

ISBN: (纸本)9781728165905

Digital fountain codes are designed to realize a reliable transmission of large-scale data and Luby Transform (LT) codes are the first practical digital fountain codes to be realized. Luby discovered that the performance and decoding efficiency are mainly determined by the degree distribution used in LT codes. So this paper focuses on designing good degree distributions for LT codes over the binary erasure channel (BEC). An improved approach to optimize the degree distribution is proposed based on the asymptotic analysis of LT codes. More importantly, the overhead and the desired erasure ratio pair set for the proposed optimization model can be realized in the asymptotic analysis of the optimal degree distribution. Simulation results show that the optimal degree distribution can provide better bit erasure ratio performance especially at low overheads.

关键词： digital fountain codes LT codes linear program degree distribution

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Optimization of Network Services Embedding Costs over Public and Private Clouds 34

Optimization of Network Services Embedding Costs over Public...

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34th International Conference on Information Networking (ICOIN)

作者： Morin, Cedric Texier, Geraldine Caillouet, Christelle Desmangles, Gilles Phan, Cao-Thanh IMT Atlantique IRISA Adopnet Nantes France BCOM Paris France TDF Paris France Univ Cote Azur CNRS INRIA I3S Nice France

ISBN: (纸本)9781728141985

Public cloud providers offer individuals and businesses the ability to rent IT resources to meet their needs without investing in their own hardware. At the same time, the Network Functions Virtualisation (NFV) concept promotes the migration of network operators from expensive and poorly scalable hardware network devices to virtual softwarized network functions. In order to embed those functions, network operators may decide to subscribe to public cloud offers. However, their diversity, both in terms of resource capacity and price, makes it difficult to find the optimal combination of offers that meets all needs at the lowest cost. In this paper we propose to solve this issue with an algorithm designed to help a network operator to select the best combination of offers (in terms of price) to reserve the virtual machines needed to support a set of network services. We analyze the computation time of our solution against various metrics, and estimate the cost savings compared to a traditional resource provision scheme or an unplanned resource rental strategy. Finally we evaluate the opportunity for a network operator to build its own datacenter, considering the existence of offers from public clouds.

关键词： NFV MANO cloud offers linear program

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Efficient Computation of User Optimal Traffic Assignment via Second-Order Cone and linear programming Techniques

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IEEE ACCESS 2019年 7卷 137010-137019页

作者： Wei, Wei Hu, Longxian Wu, Qiuwei Ding, Tao Tsinghua Univ Dept Elect Engn State Key Lab Power Syst Beijing 100084 Peoples R China Tech Univ Denmark Dept Elect Engn DK-2800 Lyngby Denmark Xi An Jiao Tong Univ Dept Elect Engn Xian 710049 Shaanxi Peoples R China

Static traffic assignment aims to disclose the spatial distribution of vehicular flow over a transportation network subject to given traffic demands, and plays an essential role in transportation engineering. User-optimal pattern adheres the individual rationality of motorists, in which everyone chooses a route that minimizes his own travel cost, while considering congestion effects influenced by the aggregated movement of vehicles. User optimal traffic assignment, which is also known as the user equilibrium, entails solving an optimization problem with a strictly convex objective function and linear constraints. However, the performances of general-purpose solvers are quite disappointing. This paper proposes two highly efficient computation models for the user equilibrium problem. The first one exploits the second-order cone reformulation of a convex power function, resulting in a second-order cone program, and no approximation is incurred. The second one approximates the convex objective function using a piece-wise linear function, and comes down to a linear program. An adaptive path generation oracle is devised in order to circumvent path enumeration in problem setup. Case studies demonstrate that the proposed method can deal with large-scale transportation systems, and outperforms the most popular iterative algorithm in the literature.

关键词： linear program second-order cone program traffic assignment user equilibrium

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