scholarly journals Cost minimization of groundwater supply to a central tank

2021 ◽  
Author(s):  
Nikolaos Nagkoulis ◽  
Konstantinos L. Katsifarakis
Keyword(s):  
Minimum Spanning Tree ◽  
Cost Minimization ◽  
Minimum Cost ◽  
Optimization Techniques ◽  
Water Tank ◽  
Pipe Network ◽  
Groundwater Exploitation ◽  
Flow Rates ◽  
Total Cost ◽  
Groundwater Supply

Abstract Minimization of groundwater exploitation cost is examined, considering: (a) Pumping from a system of wells up to a central water tank, including friction losses along the connecting pipe network and (b) amortization of network construction. Assuming that the wells are located symmetrically around the tank and directly connected to it, we derived analytically the distance between tank and wells, which minimizes the total cost. Then we compared the minimum cost of this well layout, with that of placing one well at the location of the tank and the rest symmetrically around it. Finally, we dropped any assumption on well layout, we considered that wells are connected to the tank using a minimum spanning tree and we optimized well locations and flow rates using genetic algorithms. For up to 8 wells, the resulting minimum cost is comparable to that of the symmetrical cases, even when the optimal well layout is quite different. Moreover, the analytical solution, derived for the symmetrical case, can serve to evaluate solutions achieved by sophisticated optimization techniques.

Optimal planning model for rehabilitation of water networks

2004 ◽  
Vol 4 (3) ◽  
pp. 133-148 ◽  
Author(s):  
J.-H. Kim ◽  
C.-W. Baek ◽  
D.-J. Jo ◽  
E.-S. Kim ◽  
M.-J. Park
Keyword(s):  
Harmony Search ◽  
Optimization Techniques ◽  
Optimal Decision ◽  
Optimal Planning ◽  
Planning Model ◽  
Pipe Network ◽  
Water Networks ◽  
Network Systems ◽  
Capital Costs ◽  
Hydraulic Reliability

An optimal planning model for rehabilitation of water networks is presented. Capital costs (replacement, rehabilitation and repairing costs), benefits (by the reduction of pumping cost and leakage cost), and hydraulic reliability are used for making an optimal decision for the rehabilitation plan of a water pipe network. KYPIPE is used for checking the hydraulic reliability. A multi-objective optimization model is successfully developed in this study. And the task is tackled using a new meta-heuristic algorithm, Harmony Search, for solving a large optimization problem to which conventional optimization techniques are poorly suited. Five different models with different objective functions are developed and tested according to various conditions considered in this study. These models provide more options for the rehabilitation of pipe network systems compared to previously suggested models in the literature.

scholarly journals FUZZY SHORTEST ROUTE ALGORITHM FOR TELEPHONE LINE CONNECTION USING THE LC-MST ALGORITHM

2015 ◽  
Vol 2 (2) ◽  
pp. 37-39
Author(s):  
Vijayalakshmi D ◽  
Kalaivani R
Keyword(s):  
Transmission Lines ◽  
Spanning Tree ◽  
Minimum Spanning Tree ◽  
Minimum Cost ◽  
Distribution Networks ◽  
Minimum Length ◽  
Fuzzy Graph ◽  
Telephone Line ◽  
Water Pipelines ◽  
Communication Links

In computer science, there are many algorithms that finds a minimum spanning tree for a connected weighted undirected fuzzy graph. The minimum length (or cost) spanning tree problem is one of the nicest and simplest problems in network optimization, and it has a wide variety of applications. The problem is tofind a minimum cost (or length) spanning tree in G. Applications include the design of various types of distribution networks in which the nodes represent cities, centers etc.; and edges represent communication links (fiber glass phone lines, data transmission lines, cable TV lines, etc.), high voltage power transmissionlines, natural gas or crude oil pipelines, water pipelines, highways, etc. The objective is to design a network that connects all the nodes using the minimum length of cable or pipe or other resource in this paper we find the solution to the problem is to minimize the amount of new telephone line connection using matrixalgorithm with fuzzy graph.

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 Optimized Procedure to Schedule Physicians in an Intensive Care Unit: A Case Study

Mathematics ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1976
Author(s):  
Lotfi Hidri ◽  
Achraf Gazdar ◽  
Mohammed M. Mabkhot
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Cost Minimization ◽  
Optimal Schedule ◽  
Real Life ◽  
Real Data ◽  
Experimental Tests ◽  
Operating Costs ◽  
Healthcare Personnel ◽  
Total Cost

Hospitals are facing an important financial pressure due to the increasing of the operating costs. Indeed, the growth for the hospitals’ services demand causes a rising in the number of required qualified personnel. Enlarging the personnel number increases dramatically the fixed total cost. Based on some studies, 50% of operating costs in US hospitals are allocated to healthcare personnel. Therefore, reducing these types of costs without damaging the service quality becomes a priority and an obligation. In this context, several studies focused on minimizing the total cost by producing optimal or near optimal schedules for nurses and physicians. In this paper, a real-life physicians scheduling problem with cost minimization is addressed. This problem is encountered in an Intensive Care Unit (ICU) where the current schedule is manually produced. The manual schedule is generating a highly unbalanced load within physicians in addition to a high cost overtime. The manual schedule preparation is a time consuming procedure. The main objective of this work is to propose a procedure that systematically produces an optimal schedule. This optimal schedule minimizes the total overtime within a short time and should satisfies the faced constraints. The studied problem is mathematically formulated as an integer linear program. The constraints are real, hard, and some of them are non-classical ones (compared to the existing literature). The obtained mathematical model is solved using a state-of-the-art software. Experimental tests on real data have shown the performance of the proposed procedure. Indeed, the new optimal schedules reduce the total overtime by up to 69%. In addition, a more balanced workload for physicians is obtained and several physician preferences are now satisfied.

Evaluation of Passive Anti-Fouling Technology Applied to CO2 Heat Pump Water Heaters

2014 ◽  
Author(s):  
Portia Murray ◽  
Stephen J. Harrison ◽  
Ben Stinson
Keyword(s):  
Heat Transfer ◽  
Water Supply ◽  
Heat Pump ◽  
Hot Water ◽  
Normal Operation ◽  
Mineral Deposits ◽  
Reverse Direction ◽  
Water Tank ◽  
Flow Rates ◽  
Water Heaters

Heat pump water heaters are increasing in popularity due to their increased energy efficiency and low environmental impact. This paper describes the experimental testing of a transcritical CO2 heat pump water heater at Queen’s University. A modified 4.5 kW Eco-Cute unit was studied. It sourced heat from a constant temperature water supply and rejected the heat to a 273 litre hot water tank through a gas-cooler. The high temperatures that occur in the gas-cooler of this unit make it ideally suited for natural convection, (i.e., thermosyphon) circulation on the potable water side. This has the potential to reduce pumping power, simplify system operation and design, and increase thermal stratification in the hot water storage tank. This configuration, however, is susceptible to the accumulation of sediments, scale and mineral deposits (i.e., fouling) in geographic regions where high mineral deposits may be present in the water supply. To counteract fouling in these cases, a passive back-flushing system was proposed to prevent the accumulation of deposits on the heat transfer surfaces of the gas-cooler. As hot water is drawn from the system, the cold “mains” supply water is directed through the gas-cooler in the reverse direction of normal operation, scouring the heat transfer surfaces and dissolving deposits of inverse-soluble salts which are a major contributor to fouling on hot heat transfer surfaces. The gas-cooler used was a specially designed unit that, although offering high performance in a compact unit, may be susceptible to the fouling and blockage of the heat transfer passages when used at thermosyphon flow rates. Experiments were conducted to evaluate the effects of the back-flush operation on heat pump performance (i.e., COP) and operation. These were conducted under controlled laboratory conditions, at a range of draw flow rates and temperatures, and are summarized in this paper.

scholarly journals A total cost minimization control for wastewater treatment process by using extremum seeking control

2017 ◽  
Vol 12 (4) ◽  
pp. 751-760 ◽  
Author(s):  
Osamu Yamanaka ◽  
Yuuta Onishi ◽  
Ryo Namba ◽  
Takumi Obara ◽  
Yukio Hiraoka
Keyword(s):  
Cost Minimization ◽  
Extremum Seeking ◽  
Cost Index ◽  
Optimal Point ◽  
Wastewater Treatment Process ◽  
Extremum Seeking Control ◽  
Total Cost ◽  
Time Optimal ◽  
Optimal Control Scheme ◽  
Point Invariant

Abstract This paper presents a real-time optimal control scheme based on a total cost index (TCI) by using the so-called extremum seeking control (ESC). The ESC searches the minimum value of a given performance index where the TCI consisting of the operational cost and the effluent quality cost is used as the index. An improved ESC is proposed where a transformed TCI by monotonically increasing function is utilized to improve the convergence property of the ESC while keeping the argument of the optimal point invariant. The feasibility of the ESC is tested for two types of pseudo-anaerobic-oxic process control: one is the return sludge recycle ratio control, and the other is the aeration control for an alternate zone which can be anaerobic or aerobic depending on the influent condition. Simulation study illustrates that the proposed ESC is able to find a near optimal point successfully and the TCI can be reduced by about 2.7 to 3.8% compared with that of a typical operating condition.

Optimizing operations in 3‐D land seismic surveys

Geophysics ◽  
2001 ◽  
Vol 66 (6) ◽  
pp. 1818-1826 ◽  
Author(s):  
Douglas J. Morrice ◽  
Astrid S. Kenyon ◽  
Christian J. Beckett
Keyword(s):  
Minimum Cost ◽  
Seismic Survey ◽  
Production Parameter ◽  
Microsoft Excel ◽  
Trade Off ◽  
Seismic Surveys ◽  
Total Cost ◽  
Decision Variables ◽  
Conduct Sensitivity Analysis ◽  
Operational Constraints

We formulate and solve a mathematical programming optimization model to find a minimum cost solution for an orthogonal split‐spread design in a 3‐D land seismic survey. The model contains decision variables on source and receiver location spacings, the amount of receiver equipment, and the production rate of the seismic crews. The model includes operational constraints for source and receiver movements. It also includes geophysical constraints for fold coverage, offset, and azimuth. To demonstrate the efficacy of the model, we include an example and solve it using the nonlinear optimization solver in Microsoft Excel. The model results demonstrate the classic trade‐off between source and receiver points to satisfy the geophysical requirements. In addition, we conduct sensitivity analysis on an important production parameter: the maximum number of source points that can be shot per day. We show that although changes to this parameter do not impact the decision variables, such changes do have a significant effect on the total cost of the survey.

scholarly journals Replenishment Model with Entropic Order Quantity for Deteriorating Items under Inflation

2021 ◽  
pp. 34-47
Author(s):  
P. K. Tripathy ◽  
Anima Bag
Keyword(s):  
Cost Minimization ◽  
Optimal Solution ◽  
Deteriorating Items ◽  
Optimal Order ◽  
Selling Price ◽  
Order Quantity ◽  
Total Cost ◽  
Purchase Cost ◽  
Holding Cost ◽  
Special Approach

The purpose of the current paper is to determine an optimal order quantity so as to minimize the total cost of the inventory system of a business enterprise. The model is developed for deteriorating items with stock and selling price dependent demand under inflation without permitting shortage. Optimal solution is achieved by cost minimization strategy considering replenishment cost, purchase cost, holding cost and deterioration cost with a special approach to entropy cost for bulk size purchasing units. The effectiveness of the proposed model has been avowed through empirical investigation. Sensitivity analysis has been accomplished to deduce managerial insights. Findings suggest that an increased inflationary effect results in increment in the system total cost. The paper can be extended by allowing shortage. The model can be utilized in the business firms dealing with bulk purchasing units of electric equipments, semiconductor devices, photographic films and many more.

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