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Implementing a parametric maximum flow algorithm for optimal open pit mine design under uncertain supply and demand

JOURNAL OF THE OPERATIONAL RESEARCH SOCIETY 2013年第2期64卷 185-197页

作者： Asad, M. W. A. Dimitrakopoulos, R. McGill Univ COSMO Stochast Mine Planning Lab Montreal PQ Canada

Conventional open pit mine optimization models for designing mining phases and ultimate pit limit do not consider expected variations and uncertainty in metal content available in a mineral deposit (supply) and commodity prices (market demand). Unlike the conventional approach, a stochastic framework relies on multiple realizations of the input data so as to account for uncertainty in metal content and financial parameters, reflecting potential supply and demand. This paper presents a new method that jointly considers uncertainty in metal content and commodity prices, and incorporates time-dependent discounted values of mining blocks when designing optimal production phases and ultimate pit limit, while honouring production capacity constraints. The structure of a graph representing the stochastic framework is proposed, and it is solved with a parametric maximum flow algorithm. Lagragnian relaxation and the subgradient method are integrated in the proposed approach to facilitate producing practical designs. An application at a copper deposit in Canada demonstrates the practical aspects of the approach and quality of solutions over conventional methods, as well as the effectiveness of the proposed stochastic approach in solving mine planning and design problems. Journal of the Operational Research Society (2013) 64, 185-197. doi:10.1057/jors.2012.26 Published online 25 April 2012

关键词： open pit mine optimization maximum flow algorithm Lagrangian relaxation subgradient method

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Feasibility study of China's foreign trade transformation and upgrading mode based on maximum flow algorithm

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CLUSTER COMPUTING-THE JOURNAL OF NETWORKS SOFTWARE TOOLS AND APPLICATIONS 2019年第6-Sup期22卷 14445-14450页

作者： Wang, Hui Jiangxi Univ Finance & Econ Coll Modern Econ & Management Nanchang Jiangxi Peoples R China

With the development of social economy, China's foreign trade gradually develops into a green and low-carbon development, based on this situation, this paper studies the transformation and upgrading of China's foreign trade from the perspective of logistics and transportation. This article analyzes various factors that affect the efficiency of foreign trade logistics distribution and the widely used methods of logistics distribution, and gives a logistics and distribution reference model suitable for the current situation of e-commerce in our country, proposes a reference model of e-commerce logistics distribution system based on Internet environment and designs a suitable transportation route selection model and algorithm for distribution center. After testing, the algorithm in this paper is suitable for practical work, and the algorithm has important reference value for designing and improving the logistics and distribution system and improving the delivery efficiency.

关键词： maximum flow algorithm Low carbon economy Logistics and transportation

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Finding web communities by maximum flow algorithm using well-assigned edge capacities

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IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS 2004年第2期E87D卷 407-415页

作者： Imafuji, N Kitsuregawa, M Univ Tokyo Inst Ind Sci Tokyo 1538505 Japan

A web community is a set of web pages that provide resources on a specific topic. Various methods for finding web communities based on link analysis have been proposed in the literature. The method proposed in this paper is based on the method using the maximum flow algorithm proposed in [7], [8]. Our objective of using the maximum flow algorithm is to extract a subgraph which can be recognized as a good web community in the context of the quantity and the quality. This paper first discusses the features of the maximum flow algorithm based method. The previously proposed approach has a problem that a certain graph structure containing noises (i.e., irrelevant pages) is always extracted. This problem is mainly caused by edge capacities assigned a constant value. This paper proposes an assignment of variable edge capacities that are based on hub and authority scores obtained from HITS calculation. To examine the effects of our proposed method, we performed experiments using a Japanese archive crawled in February 2002. Our experimental results demonstrate that our proposed method removes noise pages caused by constant edge capacities and improves the quality of web communities.

关键词： web community web graph maximum flow algorithm HITS

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Detection of conserved domains in protein sequences using a maximum-density subgraph algorithm

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2000年第4期E83A卷 713-721页

作者： Matsuda, H Osaka Univ Grad Sch Engn Sci Toyonaka Osaka 5608531 Japan

In this paper, we propose a method for detecting conserved domains from a set of amino acid sequences that belong to a protein family. This method detects the domains as follows: first, generate fixed-length subsequences from the sequences;second, construct a weighted graph that connects any two of the subsequences (vertices) having higher similarity than a pre-defined threshold;third, search for the maximum-density subgraph for each connected component of the graph;finally, explore conserved domains in the sequences by combining the results of the previous step. From the performance results obtained by applying the method to several protein families that have complex conserved domains, we found that our method was able to detect those domains even though some domains were weakly conserved.

关键词： maximum-density subgraph approximate string comparison maximum flow algorithm protein sequence analysis computational molecular biology

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Underground stope optimization with network flow method

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COMPUTERS & GEOSCIENCES 2013年 52卷 361-371页

作者： Bai, Xiaoyu Marcotte, Denis Simon, Richard Ecole Polytech Dept Civil Geol & Min Engn Montreal PQ H3C 3A7 Canada

A new algorithm to optimize stope design for the sublevel stoping mining method is described. The model is based on a cylindrical coordinate defined around the initial vertical raise. Geotechnical constraints on hanging wall and footwall slopes are translated as precedence relations between blocks in the cylindrical coordinate system. Two control parameters with clear engineering meaning are defined to further constrain the solution: (a) the maximum distance of a block from the raise and (b) the horizontal width required to bring the farthest block to the raise. The graph obtained is completed by the addition of a source and a sink node allowing to transform the optimization program to a problem of maximum flow over the graph. The (conditional) optimal stope corresponding to the current raise location and height is obtained. The best location and height for the raise are determined by global optimization. The performance of the algorithm is evaluated with three simple synthetic deposits and one real deposit. Comparison is made with the floating stope technique. The results show that the algorithm effectively meets the geotechnical constraints and control parameters, and produce realistic optimal stope for engineering use. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： OR in natural resources Underground mining stope optimization Mining constraints maximum flow algorithm Cylindrical coordinate transformation

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Stochastic production phase design for an open pit mining complex with multiple processing streams

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ENGINEERING OPTIMIZATION 2014年第8期46卷 1139-1152页

作者： Asad, Mohammad Waqar Ali Dimitrakopoulos, Roussos van Eldert, Jeroen Curtin Univ Western Australian Sch Mines Dept Min Engn Kalgoorlie Australia McGill Univ Dept Min & Mat Engn COSMO Stochast Mine Planning Lab Montreal PQ H3A 2A7 Canada McGill Univ Dept Min & Mat Engn Montreal PQ H3A 2A7 Canada

In a mining complex, the mine is a source of supply of valuable material (ore) to a number of processes that convert the raw ore to a saleable product or a metal concentrate for production of the refined metal. In this context, expected variation in metal content throughout the extent of the orebody defines the inherent uncertainty in the supply of ore, which impacts the subsequent ore and metal production targets. Traditional optimization methods for designing production phases and ultimate pit limit of an open pit mine not only ignore the uncertainty in metal content, but, in addition, commonly assume that the mine delivers ore to a single processing facility. A stochastic network flow approach is proposed that jointly integrates uncertainty in supply of ore and multiple ore destinations into the development of production phase design and ultimate pit limit. An application at a copper mine demonstrates the intricacies of the new approach. The case study shows a 14% higher discounted cash flow when compared to the traditional approach.

关键词： mining engineering applications stochastic optimization production planning maximum flow algorithm

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A pin assignment and global routing algorithm for floorplanning

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 1998年第8期E81A卷 1725-1732页

作者： Shiohara, T Fukui, M Matsushita Soft Res Inc Semicond Software Dev Grp Moriguchi Osaka 5708501 Japan Matsushita Elect Ind Co Ltd Corp Semicond Dev Div Moriguchi Osaka 5708501 Japan

In this paper, we present a hierarchical technique for simultaneous pin assignment and global routing during floorplanning based on the minimum cost maximum integer flow algorithm with several heuristic cost functions. Furthermore, our algorithm handles feedthrough pins and equi-potential pins taking into account global routes. Our algorithm allows various user specified constraints such as pre-specified pin positions, wiring paths, wiring widths and critical nets. Experimental results including Xerox floorplanning benchmark have shown the effectiveness of the heuristics.

关键词： floorplan pin assignment global route maximum flow algorithm

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Performance evaluation of a new stochastic network flow approach to optimal open pit mine design-application at a gold mine

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JOURNAL OF THE SOUTHERN AFRICAN INSTITUTE OF MINING AND METALLURGY 2012年第7期112卷 649-655页

作者： Asad, M. W. A. Dimitrakopoulos, R. McGill Univ Dept Min & Mat Engn COSMO Stochast Mine Planning Lab Montreal PQ Canada

The optimal design of production phases and ultimate pit limit for an open pit mining operation may be generated using conventional or stochastic approaches. Unlike the conventional approach, the stochastic framework accounts for expected variability and uncertainty in metal content by considering a set of equally probable realizations (models) of the orebody. This paper evaluates the performance of a new stochastic network flow approach for the development of optimal phase design and ultimate pit limit using a gold deposit as the case study. The stochastic and conventional frameworks as considered here utilize the maximum flow and Lerchs-Grossman (LG) algorithms, respectively. The LG algorithm is restricted to considering an estimated (average-type) orebody model, while the stochastic maximum flow algorithm is developed to simultaneously use a set of simulated orebody realizations as an input. The case study demonstrates that, when compared to the conventional LG algorithm as used in the industry, the stochastic approach generates a 30 per cent increase in discounted cash flow, a 21 per cent larger ultimate pit limit, and about 7 per cent more metal, while it maintains a consistency in phase size.

关键词： open pit mine optimization maximum flow algorithm Lerchs-Grossman algorithm

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Application of artificial intelligence and communication technology to water and energy balance models

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WATER SUPPLY 2023年第7期23卷 2847-2864页

作者： Zhang, Guanxiong Jin, Yechun Wang, Bingqiang Cangzhou Normal Univ Coll Phys & Informat Engn Cangzhou 061000 Hebei Peoples R China Cangzhou Tech Coll Coll Informat Engn Cangzhou 061000 Hebei Peoples R China

The precise correction of water and energy balance is a significant difficulty in studying turbulence energy balance and water flow for agricultural purposes. The need for efficient water and energy management is growing as the world struggles to keep up with rising water and energy demands. This research examines artificial intelligence (AI)'s impact on the water flow and energy balance confluence subnetwork of sensing elements out of all the original network's nodes. The study proposed an AI-based optimized sensor energy balance model (AI-SEBM) that uses pressure data to maintain energy balance in turbines and save water with the optimized energy source for agriculture usage. This research explores the potential for installing Kalpan hydraulic turbines, which are most effective during half load operation, and to forecast all loads with little computing effort to balance energy in turbulence. To anticipate daily pressure readings and energy consumption across all nodes in the network, an AI-based optimization wireless sensor network is designed for communication and linked to an energy balance system. Sensors are strategically deployed at the network's nerve centres. The maximum flow algorithm is used for a grid representing the water and energy balance to determine the positions of the virtual nodes.

关键词： advanced harmonic Bayesian approach artificial intelligence maximum flow algorithm wireless sensor networks

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Optimal Management of a Multispecies Shorebird Flyway under Sea-Level Rise

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CONSERVATION BIOLOGY 2014年第6期28卷 1710-1720页

作者： Iwamura, Takuya Fuller, Richard A. Possingham, Hugh P. Stanford Univ Dept Biol Stanford CA 94305 USA Stanford Univ Dept Environm Earth Syst Sci Stanford CA 94305 USA Univ Queensland Sch Biol Sci Australian Res Council Ctr Excellence Environm De St Lucia Qld 4072 Australia Univ London Imperial Coll Sci Technol & Med Dept Life Sci Ascot SL5 7PY Berks England

Every year, millions of migratory shorebirds fly through the East Asian-Australasian Flyway between their arctic breeding grounds and Australasia. This flyway includes numerous coastal wetlands in Asia and the Pacific that are used as stopover sites where birds rest and feed. Loss of a few important stopover sites through sea-level rise (SLR) could cause sudden population declines. We formulated and solved mathematically the problem of how to identify the most important stopover sites to minimize losses of bird populations across flyways by conserving land that facilitates upshore shifts of tidal flats in response to SLR. To guide conservation investment that minimizes losses of migratory bird populations during migration, we developed a spatially explicit flyway model coupled with a maximum flow algorithm. Migratory routes of 10 shorebird taxa were modeled in a graph theoretic framework by representing clusters of important wetlands as nodes and the number of birds flying between 2 nodes as edges. We also evaluated several resource allocation algorithms that required only partial information on flyway connectivity (node strategy, based on the impacts of SLR at nodes;habitat strategy, based on habitat change at sites;population strategy, based on population change at sites;and random investment). The resource allocation algorithms based on flyway information performed on average 15% better than simpler allocations based on patterns of habitat loss or local bird counts. The Yellow Sea region stood out as the most important priority for effective conservation of migratory shorebirds, but investment in this area alone will not ensure the persistence of species across the flyway. The spatial distribution of conservation investments differed enormously according to the severity of SLR and whether information about flyway connectivity was used to guide the prioritizations. With the rapid ongoing loss of coastal wetlands globally, our method provides insight into efficient

关键词： coastal wetlands conservation prioritization East Asian-Australasian Flyway ecological networks global migrants graph theory maximum flow algorithm migratory shorebirds Algoritmo de flujo maximo aves costeras migratorias humedales costeros migrantes globales priorizacion de la conservacion redes ecologicas ruta migratoria Asia-Australasia de Oriente teoria de graficos

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