scholarly journals A Novel Method for Network Design and Optimization of District Energy Systems: Considering Network Topology Planning and Pipe Diameter

2021 ◽  
Vol 11 (4) ◽  
pp. 1795
Author(s):  
Jiazheng Wu ◽  
Hongyun Liu ◽  
Yingjun Ruan ◽  
Shanshan Wang ◽  
Jiamin Yuan ◽  
...  
Keyword(s):  
Network Design ◽  
Network Topology ◽  
Minimum Spanning Tree ◽  
Design Method ◽  
Minimum Cost ◽  
Topology Design ◽  
Pipe Diameter ◽  
Pipeline Construction ◽  
The Road ◽  
The Cost

This paper proposes a new network topology design method that considers all the road nodes, energy stations and load centers to ensure the distribution of pipes along the road. The traditional graph theory and Prim Minimum Spanning Tree (MST) are used to simplify the map and minimize the length of the pipeline. After analyzing the limitations of the traditional network topology model, Point-to-Point (PTP), we present a new model, Energy Station-to-Load Point (ESLP). The model is optimized by minimum cost, not the shortest path. Finally, Pipe Diameter Grading (PDG) is proposed based on ESLP by solving for the pipe diameter that gives the minimum cost under different load demands in the process of optimization. The network design method is effectively applied in a case, and the results show that the path of the optimized plan is 1.88% longer than that of the pre-optimized plan, but the cost is 2.38% lower. The sensitivity analysis shows that the cost of pipeline construction, project life and electricity price all have an impact on the optimization results, and the cost of pipeline construction is the most significant. The difference between the different classifications of pipelines affects whether PDG is effective or not.

scholarly journals Algorithms for the power-p Steiner tree problem in the Euclidean plane

2018 ◽  
Vol 25 (4) ◽  
pp. 28
Author(s):  
Christina Burt ◽  
Alysson Costa ◽  
Charl Ras
Keyword(s):  
Spanning Tree ◽  
Minimum Spanning Tree ◽  
Valid Inequalities ◽  
Minimum Cost ◽  
Performance Ratio ◽  
Mixed Integer ◽  
Steiner Tree Problem ◽  
Steiner Points ◽  
Tree Construction ◽  
The Cost

We study the problem of constructing minimum power-$p$ Euclidean $k$-Steiner trees in the plane. The problem is to find a tree of minimum cost spanning a set of given terminals where, as opposed to the minimum spanning tree problem, at most $k$ additional nodes (Steiner points) may be introduced anywhere in the plane. The cost of an edge is its length to the power of $p$ (where $p\geq 1$), and the cost of a network is the sum of all edge costs. We propose two heuristics: a ``beaded" minimum spanning tree heuristic; and a heuristic which alternates between minimum spanning tree construction and a local fixed topology minimisation procedure for locating the Steiner points. We show that the performance ratio $\kappa$ of the beaded-MST heuristic satisfies $\sqrt{3}^{p-1}(1+2^{1-p})\leq \kappa\leq 3(2^{p-1})$. We then provide two mixed-integer nonlinear programming formulations for the problem, and extend several important geometric properties into valid inequalities. Finally, we combine the valid inequalities with warm-starting and preprocessing to obtain computational improvements for the $p=2$ case.

scholarly journals Automatic Generation of Multidestination Routes for Autonomous Wheelchairs

2020 ◽  
Vol 32 (6) ◽  
pp. 1121-1136
Author(s):  
Yusuke Mori ◽  
◽  
Katashi Nagao
Keyword(s):  
Texture Analysis ◽  
Minimum Cost ◽  
Automatic Generation ◽  
The Self ◽  
The Road ◽  
Road Surfaces ◽  
Surface Image ◽  
Route Information ◽  
The Cost ◽  
Route Search

To solve the problem of autonomously navigating multiple destinations, which is one of the tasks in the Tsukuba Challenge 2019, this paper proposes a method for automatically generating the optimal travel route based on costs associated with routes. In the proposed method, the route information is generated by playing back the acquired driving data to perform self-localization, and the self-localization log is stored. In addition, the image group of road surfaces is acquired from the driving data. The costs of routes are generated based on texture analysis of the road surface image group and analysis of the self-localization log. The cost-added route information is generated by combining the costs calculated by the two methods, and by assigning the combined costs to the route. The minimum-cost multidestination route is generated by conducting a route search using cost-added route information. Then, we evaluated the proposed method by comparing it with the method of generating the route using only the distance cost. The results confirmed that the proposed method generates travel routes that account for safety when the autonomous wheelchair is being driven.

scholarly journals Shortest Path from Bandar Tun Razak to Berjaya Times Square using Dijkstra Algorithm

2020 ◽  
Vol 5 (4) ◽  
pp. 59-65
Author(s):  
Nur Syuhada Muhammat Pazil ◽  
Norwaziah Mahmud Mahmud ◽  
Siti Hafawati Jamaluddin Jamaluddin
Keyword(s):  
Shortest Path ◽  
Minimum Cost ◽  
Dijkstra Algorithm ◽  
Kuala Lumpur ◽  
Times Square ◽  
The Road ◽  
C Programming ◽  
Travelling Time ◽  
On The Road ◽  
The Cost

The shortest path is an issue that involves the route from one point (nodes) to another. It is to find a path with a minimum travelling time. Nowadays, traffic problems have affected many transport users especially in Kuala Lumpur area. The time wasted on the road causes a lot of problems to the users. Furthermore, the costs between two destinations are rather expensive. Therefore, the inability of users to use the shortest path has attracted the researcher to propose several travel alternatives to overcome this problem. In addition, this study will help to improve the efficiency of the road and make people want to use it more often. The objectives of this study are to find the shortest path from Bandar Tun Razak to Berjaya Times Square and to cut down the cost between these two destinations. The time of the shortest path problem and the cost problem are drawn separately. Moreover, Dijkstra algorithm is applied to find the shortest path. The shortest path is calculated by using C programming of Dev C++. Nevertheless, both time and cost of shortest path are constructed in different paths. The time and cost of the journey are described by driving a car from Bandar Tun Razak to Lebuhraya SMART to Kampung Pandan, then Berjaya Times Square. The total time taken is 23 minutes (RM8.00), whereas, the cost is based on the shortest path from Bandar Tun Razak to Taman Maluri to Seasons Tower and Berjaya Times Square. The minimum cost is RM4.00 (30 minutes).

A method for simultaneous minimal-cost supply node location and network design in pipelined infrastructure.

2021 ◽  
Author(s):  
Christropher Yeates ◽  
Cornelia Schmidt-Hattenberger ◽  
David Bruhn
Keyword(s):  
Network Design ◽  
Network Topology ◽  
Learning Algorithm ◽  
Distribution Network ◽  
Minimum Cost ◽  
Initial Guess ◽  
Low Carbon ◽  
Exact Methods ◽  
Oil Pipeline ◽  
Node Position

<p>Designing low-cost infrastructure networks for transport of hydrogen represents a key step in the adoption and penetration of hydrogen technology in a low-carbon energy future.</p><p>For hydrogen distribution, network design amounts to creating pipeline systems in which supply is matched to demand through a transportation system that respects multiple constraints (technical, social, environmental) and minimizes cost. This can equate to recycling pre-existing pipelines or building new ones, but also involves the placement of carefully chosen supply nodes.</p><p>In a multi-level distribution network, supply nodes may assume many roles from large-capacity geological storage facilities, to local relay nodes addressing the end customers.</p><p>Finding minimum-cost pipeline network designs in which supply node locations are already chosen is itself a well-studied combinatorial optimization problem (Cayley’s formula predicts  possible spanning trees for  nodes) for which multiple heuristic and exact methods are known [1].</p><p>Allowing the supply node to take any position within the network renders the problem significantly more complex as the minimum-cost network topology (the specific connections to between nodes) will potentially change for each new supply node position.</p><p>We propose a heuristic algorithm that finds good solutions in a reasonable amount of time based on a back-and-forth between:</p><p>- Repositioning optimally the supply node, while maintaining the same connections to the supply node (reduces cost)</p><p>- Optimizing the network topology, assuming a fixed supply node position (also reduces cost)</p><p>The algorithm stops once no further cost reductions for the network design are found. The algorithm output is found to be sensitive to the initial guess of the supply node position, the initial guess of the connections to the supply node, and to the specific “path” of the back-and-forth taken to reach the given local minimum. As such, a good initial guess for a “housing polygon”, i.e. the nodes to which supply node is directly connected to, is crucial in finding the minimum-cost solution, and in the shortest time possible. We attempt to make this initial guess with a machine learning algorithm, with features describing the geometrical distribution of node capacity, as well as elementary network concepts.</p><p>Finally, an example is provided on a model hydrogen network comprised of typical elements and realistic cost-functions.</p><p> </p><p>[1]: Brimberg J, Hansen P, Lin K, Mladenovi N, Breton M, Brimberg, J (2003) An oil pipeline design problem. Operations Research, 51(2):228–239. https://doi.org/10.1287/opre.51.2.228.12786</p>

scholarly journals Heuristic Methods for Minimum-Cost Pipeline Network Design – a Node Valency Transfer Metaheuristic

2021 ◽  
Author(s):  
Christopher Yeates ◽  
Cornelia Schmidt-Hattenberger ◽  
Wolfgang Weinzierl ◽  
David Bruhn
Keyword(s):  
Network Design ◽  
Large Scale ◽  
Low Cost ◽  
Minimum Cost ◽  
Local Flow ◽  
Complexity Of Algorithms ◽  
Pipeline Networks ◽  
Optimization Heuristics ◽  
Novel Algorithms ◽  
The Cost

AbstractDesigning low-cost network layouts is an essential step in planning linked infrastructure. For the case of capacitated trees, such as oil or gas pipeline networks, the cost is usually a function of both pipeline diameter (i.e. ability to carry flow or transferred capacity) and pipeline length. Even for the case of incompressible, steady flow, minimizing cost becomes particularly difficult as network topology itself dictates local flow material balances, rendering the optimization space non-linear. The combinatorial nature of potential trees requires the use of graph optimization heuristics to achieve good solutions in reasonable time. In this work we perform a comparison of known literature network optimization heuristics and metaheuristics for finding minimum-cost capacitated trees without Steiner nodes, and propose novel algorithms, including a metaheuristic based on transferring edges of high valency nodes. Our metaheuristic achieves performance above similar algorithms studied, especially for larger graphs, usually producing a significantly higher proportion of optimal solutions, while remaining in line with time-complexity of algorithms found in the literature. Data points for graph node positions and capacities are first randomly generated, and secondly obtained from the German emissions trading CO2 source registry. As political will for applications and storage for hard-to-abate industry CO2 emissions is growing, efficient network design methods become relevant for new large-scale CO2 pipeline networks.

A method of network topology optimization design considering application process characteristic

2018 ◽  
Vol 32 (07) ◽  
pp. 1850091 ◽  
Author(s):  
Chunlin Wang ◽  
Ning Huang ◽  
Yanan Bai ◽  
Shuo Zhang
Keyword(s):  
Topology Optimization ◽  
Network Design ◽  
Communication Networks ◽  
Network Topology ◽  
Optimization Design ◽  
Topology Design ◽  
Application Process ◽  
Network Application ◽  
Network Topology Optimization ◽  
Process Characteristic

Communication networks are designed to meet the usage requirements of users for various network applications. The current studies of network topology optimization design mainly considered network traffic, which is the result of network application operation, but not a design element of communication networks. A network application is a procedure of the usage of services by users with some demanded performance requirements, and has obvious process characteristic. In this paper, we first propose a method to optimize the design of communication network topology considering the application process characteristic. Taking the minimum network delay as objective, and the cost of network design and network connective reliability as constraints, an optimization model of network topology design is formulated, and the optimal solution of network topology design is searched by Genetic Algorithm (GA). Furthermore, we investigate the influence of network topology parameter on network delay under the background of multiple process-oriented applications, which can guide the generation of initial population and then improve the efficiency of GA. Numerical simulations show the effectiveness and validity of our proposed method. Network topology optimization design considering applications can improve the reliability of applications, and provide guidance for network builders in the early stage of network design, which is of great significance in engineering practices.

A generalized fuzzy cost efficiency model

2020 ◽  
Vol 54 (6) ◽  
pp. 1775-1791
Author(s):  
Nazila Aghayi ◽  
Samira Salehpour
Keyword(s):  
Cost Efficiency ◽  
Minimum Cost ◽  
Extensive Literature ◽  
Data Envelopment ◽  
Fuzzy Environment ◽  
Decision Making Unit ◽  
Production Possibility Set ◽  
Fuzzy Cost ◽  
The Cost ◽  
Generalized Cost

The concept of cost efficiency has become tremendously popular in data envelopment analysis (DEA) as it serves to assess a decision-making unit (DMU) in terms of producing minimum-cost outputs. A large variety of precise and imprecise models have been put forward to measure cost efficiency for the DMUs which have a role in constructing the production possibility set; yet, there’s not an extensive literature on the cost efficiency (CE) measurement for sample DMUs (SDMUs). In an effort to remedy the shortcomings of current models, herein is introduced a generalized cost efficiency model that is capable of operating in a fuzzy environment-involving different types of fuzzy numbers-while preserving the Farrell’s decomposition of cost efficiency. Moreover, to the best of our knowledge, the present paper is the first to measure cost efficiency by using vectors. Ultimately, a useful example is provided to confirm the applicability of the proposed methods.

Main approaches to estimating the cost of shareholder equity of oil and gas producers

2020 ◽  
Vol 26 (3) ◽  
pp. 685-697
Author(s):  
O.V. Shimko
Keyword(s):  
Oil And Gas ◽  
Oil Prices ◽  
Minimum Cost ◽  
Free Cash Flow ◽  
Annual Reports ◽  
Comparative Approach ◽  
Economic Activities ◽  
Advantages And Disadvantages ◽  
Oil And Gas Producers ◽  
The Cost

Subject. The study analyzes generally accepted approaches to assessing the value of companies on the basis of financial statement data of ExxonMobil, Chevron, ConocoPhillips, Occidental Petroleum, Devon Energy, Anadarko Petroleum, EOG Resources, Apache, Marathon Oil, Imperial Oil, Suncor Energy, Husky Energy, Canadian Natural Resources, Royal Dutch Shell, Gazprom, Rosneft, LUKOIL, and others, for 1999—2018. Objectives. The aim is to determine the specifics of using the methods of cost, DFC, and comparative approaches to assessing the value of share capital of oil and gas companies. Methods. The study employs methods of statistical analysis and generalization of materials of scientific articles and official annual reports on the results of financial and economic activities of the largest public oil and gas corporations. Results. Based on the results of a comprehensive analysis, I identified advantages and disadvantages of standard approaches to assessing the value of oil and gas producers. Conclusions. The paper describes pros and cons of the said approaches. For instance, the cost approach is acceptable for assessing the minimum cost of small companies in the industry. The DFC-based approach complicates the reliability of medium-term forecasts for oil prices due to fluctuations in oil prices inherent in the industry, on which the net profit and free cash flow of companies depend to a large extent. The comparative approach enables to quickly determine the range of possible value of the corporation based on transactions data and current market situation.

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