Permissible Cost Research Articles

Finding the most navigable path in road networks

Input to the Most Navigable Path (MNP) problem consists of the following: (a) a road network represented as a directed graph, where each edge is associated with numeric attributes of cost and “navigability score” values; (b) a source and a destination and; (c) a budget value which denotes the maximum permissible cost of the solution. Given the input, MNP aims to determine a path between the source and the destination which maximizes the navigability score while constraining its cost to be within the given budget value. The problem can be modeled as the arc orienteering problem which is known to be NP-hard. The current state-of-the-art for this problem may generate paths having loops, and its adaptation for MNP that yields simple paths, was found to be inefficient. In this paper, we propose five novel algorithms for the MNP problem. Our algorithms first compute a seed path from the source to the destination, and then modify the seed path to improve its navigability. We explore two approaches to compute the seed path. For modification of the seed path, we explore different Dynamic Programming based approaches. We also propose an indexing structure for the MNP problem which helps in reducing the running time of some of our algorithms. Our experimental results indicate that the proposed solutions yield comparable or better solutions while being orders of magnitude faster than the current state-of-the-art for large real road networks.

Cost-Optimized Submarine Cables Using Massive Spatial Parallelism

We study the techno-economics of submarine systems constrained by a fixed electrical power supply. We show significant cost savings for high-capacity submarine systems using massive space-division multiplexing (SDM), even without assuming any savings from SDM-specific subsystem integration. Systems with about 100 parallel optical paths, e.g., $\sim$ 50 fiber pairs are shown to provide minimum cost/bit, operating at reduced spectral efficiencies and deep within the linear regime. While advanced nonlinearity-optimized fibers and digital nonlinearity compensation schemes provide little to no gain in such systems, SDM integration of amplifiers and transponders is shown to be a source for significant additional cost savings. We further examine the permissible cost premium for multicore fibers in such massively parallel systems and revisit various design tradeoffs for optical amplifiers, showing that a reduced noise figure can be traded for better power conversion efficiency. We also evaluate potential gains from increasing the available electrical supply power and discuss reliability aspects of massively parallel submarine systems.

Multi-item EOQ model with nonlinear unit holding cost and partial backordering: moth-flame optimization algorithm

In this paper, a multi-item multi-constrained Economic Order Quantity model with nonlinear unit holding cost and partial backordering is proposed. To develop an applicable model, different technical, physical, and strategic constraints are considered such as available budget, warehouse capacity, total permissible holding cost, and total permissible backordering cost constraints. The goal is to determine the lengths of inventory cycles, where the inventory level is positive and negative such that the total inventory costs are minimized. In addition, backordering rate during shortage period for each product is considered as a decision variable which can significantly reduce the total inventory costs. Due to complexity and nonlinearity of the proposed model, interior-point method and Moth-Flame optimization algorithm are utilized to solve the model in different sizes. At the end, the performance of the solution methods is compared statistically considering three measures to determine the superior solution method.

Effect of Synergic Controlled Pulsed and Manual Gas Metal ARC Welding Processes on Mechanical and Metallurgical Properties of AISI 430 Ferritic Stainless Steel

Abstract The gas metal arc is widely used in manufacturing industries because of the high metal deposition rate and ease of automation with better weld quality at permissible cost than other welding processes in joining similar and dissimilar metals. AISI 430 steel is normally difficult to weld by melting methods, due to the associated problems such as grain growth. For this purpose, AISI 430 ferritic stainless steel couples of 10 mm thick were welded by the synergic controlled pulsed (GMAW-P) and manual gas metal arc (GMAW) welding techniques. The interface appearances of the welded specimens were examined by scanning electron microscopy (SEM). Structural changes in the weld zone were analysed by energy dispersive spectrometry (EDS) and X-ray diffraction (X-RD). Microhardness, notch charpy and tensile tests were conducted to determine the mechanical properties of specimens. Accordingly, the best result was obtained from the GMAW-P technique.

On the capacity assignment problem in packet-switching computer networks

The capacity assignment problem in a packet-switching communication network is examined with a new look and under general assumptions about the form of the network cost function and a general class of delay measures, which includes as special cases all the previously proposed delay criteria. Four optimal functions: the optimal delay (cost) versus the maximum permissible cost (delay), and the optimal capacities versus the maximum permissible cost or delay, are defined. Several propositions describing the relations between these functions are given and their form is found if a separability property holds. An interesting application of these results to the flow and capacity assignment problem is also presented. The relations between different versions of the Capacity Assignment Problem (CAP) are given together with sufficient conditions for the uniqueness of the solution. Finally, algorithms for the solution of the CAP are proposed. Emphasis is given to the analysis of an algorithm appropriate for minimax delay criteria. Numerical results and comparisons with other delay measures are also included.

The Value of CO2: Framework and Results

Summary We present an engineering economic framework for estimation of the affordable price an EOR project can pay for CO2. Geologic and financial factors are considered. Two hypothetical reservoirs illustrate the framework. We describe the sensitivity of permissible cost to flooding efficiency, oil price, and internal rate of return (ROR) for each reservoir. Introduction Despite the recent decline in the price of petroleum and the present uncertainty over its future price, CO2 flooding for EOR is being considered for more and more fields. A total of $4 billion is being invested to supply the Permian Basin with CO2 - As experience is gained there, Permian Basin with CO2 - As experience is gained there, the risk for projects in other regions will be considered less. At present, CO2 flooding appears to be the least capital-intensive method for increasing reserves. However, little has been published on the project economics for CO2 flooding-in particular, the price that could be paid, or "permissible cost," for CO2 delivered to the paid, or "permissible cost," for CO2 delivered to the wellhead. This permissible cost is the subject of this paper. (An earlier paper by the authors and collaborators offered a simple, approximate approach that is superseded by the discussion presented here.) The permissible cost of CO2 depends on many factors. We will describe all the important ones, show how they can be grouped, and discuss the sensitivity of permissible cost to those factors over which the project manager permissible cost to those factors over which the project manager has least control-e.g., internal ROR. The after-tax cash flow for a generic CO2 flood is constructed. The cash flow is discounted, and the permissible cost of purchased CO2 is deduced in terms of the discounted revenue and all the other discounted costs. Our discussion is presented on two levels. First, we lay out the necessary ideas and then plug in reasonable numerical values to arrive at our quantitative results. The reader who wishes to base his or her results on different numerical values should have no trouble using our theoretical framework with those values. After-Tax Cash Flow To find the permissible Cost of CO2, we must consider the discounted, after-tax cash flow from the EOR project. We introduce this quantity and give particular project. We introduce this quantity and give particular attention to taxes. Throughout this paper, we are considering a project that is financed by 100% equity. In practice, financing may include a mixture of equity and corporate debt. However, EOR is still viewed as risky by commercial banks, and they are reluctant to lend money for it. The cash flow for each year, P, is defined to be the sum of profits, P, and depreciation, Dp, for that year: ................................. (1) Cash flow depends on revenue, costs, and taxes, as shown below: ......................... (2) Cash flow can be positive or negative. Working-interest revenue, V, equipment purchases, B, operating costs, cot, and taxes, tau, are discussed below. Working-interest revenue is defined as the oil firm's portion of revenue from oil sales. Typically, a lease portion of revenue from oil sales. Typically, a lease agreement includes a royalty payment to the owner of the oil property. Working-interest revenue is equal to (1 -i ) property. Working-interest revenue is equal to (1 -i ) (revenue), where iR is a fraction expressing the royalty rate. Equipment purchases include drilling of new injection wells, conversion of existing producer wells to injection wells, installation of additional surface flowlines, and construction of a CO2 recycling plant. A useful identity is given by the following: ............................ (3) The distinction between "capitalized" purchases, Bcap, and "expensed" purchases, Bex, is made by tax law. Capitalized purchases reduce current and future taxes through the investment tax credit and depreciation allowances, whereas expensed purchases diminish current taxes. Operating costs include direct costs (labor, auto usage, and operating supplies), well workovers, purchase of new CO2, recycling of produced CO2, and cleanup and disposal of produced water. P. 987

Nework topology for maximizing the terminal reliability in a Computer Communication Network

In the design of a Computer Communication Network (CCN), the reliability between any pair of nodes and the maximum permissible installation cost are of great importance. These characteristics are largely dependant upon the topological layout of the links, their costs and reliabilities. Having the knowledge of the topological layout of the various computer centres (nodes) and maximum permissible cost of installing the various links at their pre-assigned positions; in this paper an algorithm for obtaining an optimal network topology which gives the maximum s− t reliability is presented. The developed method is general and is computerized. The proposed method has an additional advantage that the system is not to be redesigned, if at a later stage the permissible cost is enhanced by budgetary provisions. An example illustrates the algorithm.

Topological layout of links for optimising the overall reliability in a computer communication system

Overall reliability or global availability is an important parameter in the design of the large scale computer communication systems having efficient resource sharing amongst the various computer centres. In order to design an optimal topological layout of the various links connected between the set of various geographically-distant computers, one should have knowledge of the cost and reliability of all the possible links and the maximum permissible cost. In this paper a heuristic algorithm is presented for obtaining an optimal network topology which gives the maximum overall reliability of the computer communication network. The method is general and is easily implemented on a computer.

Topological layout of links for optimizing the s-t reliability in a computer communication system

Large-scale Computer Communication Networks (CCN) are coming into use primarily because of the economy achieved through resource sharing. A fundamental consideration in the design of a CCN is the reliability between any pair of nodes and the maximum permissible cost, these characteristics being largely dependent upon the topological layout of the links, their costs and reliabilities. In this paper, having the knowledge of the locations of the various computer centres (nodes), maximum permissible cost of installing the links and the possible position of links, an heuristic algorithm for obtaining an optimal network topology which gives the maximum s-t reliability is presented. The method is general and is easily computerizable.

LASERS AND THE REACTOR IGNITION PROBLEM

Some published estimates of the laser energy (W0) required to heat an inertially confined D–T target in a pulsed fusion reactor are summarized. Assuming a thermal efficiency of 1/3 and a laser heating efficiency (target energy/laser pumping energy) of 100%, most of these estimates of W0 range between 10 and 1000 MJ, depending on the various assumptions which are made about the degree of solid-state target compression, the possibility of target tamping, and the required reactor power gain. Any energy gain due to fusion reactions in material other than the target is omitted in these calculations. These estimates of W0 are then compared with the maximum fusion outputs which can be handled with and without damage to the structure and the low permissible cost of replacing damaged components is stressed. The possibility of using nonlinear absorption of repetitively pulsed CO2 lasers to start up a steady-state stellarator which is fueled by D–T pellet injection and has an output of ~10 GW(E) is then discussed. It is shown that laser energies as low as 80 kJ may be feasible and possible advantages and difficulties of such a hybrid inertial/magnetic confinement approach are outlined.