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Number of results: 38
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Abstract

Construction risk assessment is the final and decisive stage of risk analysis. When highly changeable conditions of works execution are predicted, risk should be evaluated in the favorable, moderate, and difficult random conditions of construction. Given the random conditions, the schedule and cost estimate of the construction are developed. Based on these values, the risk of final deadline delay and the risk of total cost increase of construction completion are calculated. Next, the charts of the risks are elaborated. Risk changes are shown in the charts and are analyzed in the range [1, 0].
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Abstract

The paper presents an approach to evaluating a building throughout its whole life cycle in relation to its sustainable development. It describes basic tools and techniques of evaluating and analysing the costs in the whole life cycle of the building, such as Life Cycle Assessment, Life Cycle Management, Life Cycle Cost and Social Life Cycle Assessment. The aim of the paper is to propose a model of cost evaluation throughout the building life cycle. The model is based on the fuzzy sets theory which allows the calculations to include the risks associated with the sustainable development, with the management of the investment and with social costs. Costs incurred in the subsequent phases of the building life cycle are analysed and modelled separately by means of a membership function. However, the effect of the analysis is a global cost evaluation for the whole life cycle of the building.
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Abstract

Accommodation tourist industry is characterized by high variability. For this category of services not only the location is crucial- that does not change, but also the standard, prices and seasonality of services. In the recent years, leisure centers performing functions only during the summer time have seen the possibility to extend their activities beyond the summer months. The reasons for this are the local investments requiring qualified staff which comes from different parts of the country, Europe and the world while creating dernand for accommodations. To meet the possible demand needs and to adapt to cold season, performing thermo-modernization works is necessary. In order to find the best solution and answer those needs, analysis of the profitability of the investrnents in a chosen holiday resort was carried out. The article presents the results of the analysis based on the payback period, LCC analysis and assessment of the investments risk.
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Abstract

Methane is accompanied by most of the coal deposits. The methane hazard is excessive content of this gas in the mining excavations. This is a source of high risk security and continuity of the mine. The Piast–Ziemowit is the only non-methane mine in the Polish Mining Group. In 2015, 66,4% of the coal mined in Kompania Węglowa S.A. mines comes from methane coal seams. Methane drainage is the most effective but very costly method of combating methane hazard.The costs of prevention and eradication of methane hazard is charged to the costs of coal mining. Therefore, performance of methane drainage in the mines of the Polish Mining Group is adapted to the scale of the methane hazard. The article presents an analysis of the costs of prevention of methane hazard for mines with different absolute methane and its impact on the level of these costs.
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Abstract

One of the most important business areas of the company is the management of working capital. Energy companies that produce electricity and heat are the main consumers of steam coal, so their decision concerning stock levels is a major determinant of supply schedules. These decisions depend on legal and technical requirements as well as economic aspects. The seasonality of coal consumption jointly with pre-purchase costs and storage costs has a straight impact on delivery scheduling in a parabolic way. There is a divergence in expectations regarding delivery schedules among the coal market participants (energy, mining, transport companies). The purpose of this article is to present the concept of pricing of steam coal and transport service on the Polish market, assuming the use of price incentives, resulting in delivery scheduling during the year. The article presents selected theoretical content in the field of coal logistics and working capital management in the company, the expectations of the steam coal market participant regarding delivery schedules have been identified. The proposed concept of pricing steam coal and transport service should be discussed further in scientific and expert work.
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Abstract

The problem of research undertaken in the article concerns the adaptation of traditional models of calculating the cost of capital to the specifics of mining companies. Solutions known from the literature do not give reasonable results. This is due to the uniqueness of the activities of mining companies, in which case we are dealing with a lack of reference to the typical market situations. The aim of this article is to identify solutions that allow rational and reliable results to be obtained. One of the proposals is a modified Fama-French method. The article was tested by calculating the cost of capital in the largest Polish mining enterprises. The problem of calculation of the cost of capital is particularly important in the area of assessing the effectiveness of investment projects. The cost of capital is used as the discount rate in dynamic measures of performance, such as NPV.
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Abstract

Evolutionary computing and algorithms are well known tools of optimisation that are utilized for various areas of analogue electronic circuits design and diagnosis. This paper presents the possibility of using two evolutionary algorithms - genetic algorithm and evolutionary strategies - for the purpose of analogue circuits yield and cost optimisation. Terms: technologic and parametric yield are defined. Procedures of parametric yield optimisation, such as a design centring, a design tolerancing, a design centring with tolerancing, are introduced. Basics of genetic algorithm and evolutionary strategies are presented, differences between these two algorithms are highlighted, certain aspects of implementation are discussed. Effectiveness of both algorithms in parametric yield optimisation has been tested on several examples and results have been presented. A share of evolutionary algorithms computation cost in a total optimisation cost is analyzed.
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Abstract

The paper is devoted to the problems of exergetic cost determination. A brief description of theoretical fundamentals of exergetic cost determination and its application are presented. The applied method of calculations is based on the rules of determination of cumulative exergy consumption. The additional possibilities ensured by the exergetic cost analysis in comparison to the direct exergy consumption analysis are discussed. The presented methodology was applied for the analysis of influence of operational parameters on exergetic cost indices of steam power plant. Results of calculations concern one of the modern Polish power plant unit. Basing on the obtained results several conclusions have been formulated that show advantages of application of exergetic cost analyses.
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Abstract

The paper presents methods of determining the location of cost buffers and corresponding contingency costs in the CPM schedule based on its work breakdown structure. Application of correctly located cost buffers with appropriately established reserve costs is justified by the common overrunning of scheduled costs in construction projects. Interpolated cost buffers (CB) as separate tasks have been combined with relevant summary tasks by the starttostart (SS) relationship, whereas the time of their execution has been dynamically connected with the time of accomplishment of particular summary tasks using the “paste connection” option. Besides cost buffers linked with the group of tasks assigned to summary tasks, a definition of the cost buffer for the entire project (PCB) has been proposed, i.e. as one initial task of the entire project. Contingency costs corresponding to these buffers, depending on the data that the planner has at his disposal, can be determined using different methods, but always depend on the costs of all tasks protected by each buffer. The paper presents an exemplary schedule for a facility and the method of determining locations and cost for buffers CB and PCB, as well as their influence on the course of the curve illustrating the budgeted cost of work scheduled (BCWS). The proposed solution has been adjusted and presented with consideration of the possibilities created by the scheduling software MS Project, though its general assumptions may be implemented with application of other similar specialist tools.
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Abstract

In this article, a comparison of economic effectiveness of various heating systems dedicated to residential applications is presented: a natural gas-fueled micro-cogeneration (micro-combined heat and power – μCHP) unit based on a free-piston Stirling engine that generates additional electric energy; and three so-called classical heating systems based on: gas boiler, coal boiler, and a heat pump. Calculation includes covering the demand for electricity, which is purchased from the grid or produced in residential system. The presented analyses are partially based on an experimental investigation. The measurements of the heat pump system as well as those of the energy (electricity and heat) demand profiles in the analyzed building were conducted for a single-family house. The measurements of the μCHP unit were made using a laboratory stand prepared for simulating a variable heat demand. The overall efficiency of the μCHP was in the range of 88.6– 92.4%. The amounts of the produced/consumed energy (electricity, heat, and chemical energy of fuel) were determined. The consumption and the generation of electricity were settled on a daily basis. Operational costs of the heat pump system or coal boiler based heating system are lower comparing to the micro-cogeneration, however no support system for natural gas-based μCHP system is included.
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Abstract

Internalization of external economic effects on urban sprawl affected areas. An example of the Krakow Metropolitan Area, The study is a discussion on economic externalities, with particular emphasis on technological effects. Attention is also paid to the problem of internalization of economic external effects caused by movement (transport) in areas affected by the urban sprawl process. The research was conducted for all communes of the Krakow Metropolitan Area (KOM), as a result of which the value of: directly incurred financial losses and the value of lost time generated by the necessity of commuting and return in the space of KOM were presented.
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Abstract

This paper presents the optimal sizing of PV/Wind/Fuel Cell/Battery Hybrid Energy System for energizing a Small Scale Industrial Application or a village domestic load of 200 kW. HOMER software is used for simulation of the complete system. The solar radiation data and wind speed data used in this paper are for the place of Coimbatore, Tamil Nadu, India which is located 11.0183° N longitude and 76.9725° E latitude. The optimized sizes of components of Hybrid Power System (HPS) are found based on Levelised Cost of Energy (LCE) and total Net Present Cost (NPC). The results are presented and compared for five different combinations of HPS components. Suggestions are also presented to choose the low cost system which produces energy at low LCE.
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Abstract

In the article problems related to human labor and factors affecting the increasing use of industrial robots are discussed. Since human factors affect the production processes stability, robots are preferred to apply. The application of robots is characterized by higher performance and reliability comparing to human labor. The problem is how to determine the real difference in work efficiency between human operator and robot. The aim of the study is to develop a method that allows clearly definition of productivity growth associated with the replacement of human labor by industrial robots. Another aim of the paper is how to model robotized and manual operated workstation in a computer simulation software. Analysis of the productivity and reliability of the hydraulic press workstation operated by the human operator or an industrial robot, are presented. Simulation models have been developed taking into account the availability and reliability of the machine, operator and robot. We apply OEE (Overall Equipment Effectiveness) indicator to present how availability and reliability parameters influence over performance of the workstation, in the longer time. Simplified financial analysis is presented considering different labor costs in EU countries.
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Abstract

The In the paper, we investigate two single processor problems, which deal with the process of negotiation between a producer and a customer about delivery time of final products. This process is modelled by a due interval, which is a generalization of well known classical due date and describes a time interval, in which a job should be finished. In this paper we consider two diffierent mathematical models of due intervals. In both considered problems we should find such a schedule of jobs and such a determination of due intervals to each job, that the generalized cost function is minimized. The cost function is the maximum of the following three weighted parts: the maximum tardiness, the maximum earliness and the maximum due interval size. For the first problem we proved several properties of its optimal solution and next we show the mirror image property for both of considered problems, which helps us to provide an optimal solution for the second problem.
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Abstract

In this study the authors minimise the total process cost for the heating of solid particles in a horizontal fluidised bed by an optimal choice of the inlet heating gas temperature profile and the total gas flow. Solid particles flowed along the apparatus and were heated by a hot gas entering from the bottom of the fluidised apparatus. The hydrodynamics of the fluidised bed is described by a two-phase Kunii - Levenspiel model. We assumed that the gas was flowing only vertically, whereas solid particles were flowing horizontally and because of dispersion they could be additionally mixed up in the same direction. The mixing rate was described by the axial dispersion coefficient. As any economic values of variables describing analysing process are subject to local and time fluctuations, the accepted objective function describes the total cost of the process expressed in exergy units. The continuous optimisation algorithm of the Maximum Principle was used for calculations. A mathematical model of the process, including boundary conditions in a form convenient for optimisation, was derived and presented. The optimization results are presented as an optimal profile of inlet gas temperature. The influence of heat transfer kinetics and dispersion coefficients on optimal runs of the heating process is discussed. Results of this discussion constitute a novelty in comparison to information presented in current literature.
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Abstract

Investor bears responsibility for proper preparation of the investment process. One of his tasks is to prepare the project documentation and obtaina building permit. Frequently, during his work, there are situations and events whose im pact interferes with the design solutions. Regardless of reasons, alterations to a project constitute a source of cost risk. In each case, the Investor should be prepared for this type of a risk. Exposure to risk should be taken into account in the planning stage of the investment. Also, a model of investment execution should be chosen at this stage. The type of model is associated with the distribution of risk throughout the project. The aim of this paper is to identify events that generate risk related to alterations to Project Documentation in the context of the selection of the investment executionmodel.
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Abstract

The usefulness of untreated powdered eggshell as low-cost adsorbent for the removal of pentachlorophenol (PCP) from aqueous solutions was investigated. The most important parameters affecting the adsorption process, including the pH and ionic strength, were examined. The adsorption characteristics of PCP onto eggshell were evaluated in terms of kinetic and equilibrium parameters. The kinetic data were studied in terms of the pseudo-first order, pseudo-second order and intra-particle diffusion kinetic models. The equilibrium data were analyzed using the Langmuir, Freundlich, Sips and Redlich-Peterson isotherm models. The pseudo-second order model best described the adsorption kinetics. Using the Langmuir equation, the monolayer adsorption capacity of eggshell for PCP was found to be 0.127 mg/g. The results showed that PCP can be effectively removed from aqueous solution employing eggshell as a cheap adsorbent.
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Abstract

Electric cars (SE) are currently considered to be one of the best ways to reduce CO2 and other air emissions in the transport sector as well as noise in cities. They can reduce the dependency of road transport on imported oil in a visible way. Nevertheless, the demand for electricity for a large amount of SE in road transport is not insignificant and has an impact on the power system. The article analyzes the potential impact of SE on the demand, supply, structure and costs of electricity generation as well as emissions as a result of introducing 1 million SEs by 2025 on Polish roads, and tripling this number by 2035. The competitive electricity market model ORCED was used for the calculations. The results of the analysis indicate that regardless of the charging strategy, the demand for SEs causes a slight increase in the overall electricity demand in Poland and consequently also a slight increase in power generating costs. Even a large increase in SEs in road transport will result in a rather moderate demand for additional generation capacity, assuming that power companies will have some control over the mode of charging cars. The introduction of SEs will not reduce CO2 emissions compared to conventional cars in 2025, on the contrary will increase them regardless of the loading strategy. In 2035 however, the result depends on the charging scenario and both the increase or decrease of emissions is possible. Electric vehicles will increase SO2 net emissions, but they will contribute to a decrease in the net emissions of particulates and NOx.
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Abstract

Because of the value of time, investors are interested in obtaining economic benefits rather early and at a highest return. But some investing opportunities, e.g. mineral projects, require from an investor to freeze their capital for several years. In exchange for this, they expect adequate remuneration for waiting, uncertainty and possible opportunities lost. This compensation is reflected in the level of interest rate they demand. Commonly used approach of project evaluation – the discounted cash flow analysis – uses this interest rate to determine present value of future cash flows. Mining investors should worry about project’s cash flows with greater assiduousness – especially about those arising in first years of the project lifetime. Having regard to the mining industry, this technique views a mineral deposit as complete production project where the base sources of uncertainty are future levels of economic-financial and technical parameters. Some of them are more risky than others – this paper tries to split apart and weigh their importance by the example of Polish hard coal projects at the feasibility study. The work has been performed with the sensitivity analysis of the internal rate of return. Calculations were made using the ‘bare bones’ assumption (on all the equity basis, constant money, after tax, flat price and constant operating costs), which creates a good reference and starting point for comparing other investment alternatives and for future investigations. The first part introduces with the discounting issue; in the following sections the paper presents data and methods used for spinning off risk components from the feasibility-stage discount rate and, in the end, some recommendations are presented.
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Abstract

This paper researches the application of grey system theory in cost forecasting of the coal mine. The grey model (GM(1.1)) is widely used in forecasting in business and industrial systems with advantages of minimal data, a short time and little fluctuation. Also, the model fits exponentially with increasing data more precisely than other prediction techniques. However, the traditional GM(1.1) model suffers from the poor anti-interference ability. Aimed at the flaws of the conventional GM(1.1) model, this paper proposes a novel dynamic forecasting model with the theory of background value optimization and Fourier-series residual error correction based on the traditional GM(1.1) model. The new model applies the golden segmentation optimization method to optimize the background value and Fourier-series theory to extract periodic information in the grey forecasting model for correcting the residual error. In the proposed dynamic model, the newest data is gradually added while the oldest is removed from the original data sequence. To test the new model’s forecasting performance, it was applied to the prediction of unit costs in coal mining, and the results show that the prediction accuracy is improved compared with other grey forecasting models. The new model gives a MAPE & C value of 0.14% and 0.02, respectively, compared to 1.75% and 0.37 respectively for the traditional GM(1.1) model. Thus, the new GM(1.1) model proposed in this paper, with advantages of practical application and high accuracy, provides a new method for cost forecasting in coal mining, and then help decision makers to make more scientific decisions for the mining operation.
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Abstract

The optimization of cut-off grades is a fundamental issue for metallic ore deposits. The cut-off grade is used to classify the material as ore or waste. Due to the time value of money, in order to achieve the maximum net present value, an optimum schedules of cut-off grades must be used. The depletion rate is the rate of depletion of a mineral deposit. Variable mining costs are to be applied to the really excavated material, as some of the depletion can be left in-situ. Due to access constraints, some of the blocks that have an average grade less than the determined cut-off grade are left in-situ, some of them are excavated and dumped as waste material. Naturally, variable mining costs should be applied to the blocks of a mineral deposit that are actually excavated. The probability density function of an exponential distribution is used to find the portion of the depletion rate over the production rate that is to be left in-situ. As a result, inverse probability density function is to be applied as the portion of the depletion rate over the production rate that is to be excavated and dumped. The parts of a mineral deposit that are excavated but will be dumped as waste material incur some additional cost of rehabilitation that is to be included in the algorithm of the cut-off grades optimization. This paper describes the general problem of cut-off grades optimization and outlines the further extension of the method including various depletion rates and variable rehabilitation cost. The author introduces the general background of the use of grid search in cut-off grades optimization by using various depletion rates and variable rehabilitation cost. The software developed in this subject is checked by means of a case study.
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Abstract

We investigate the problem of setting revenue sharing rules in a team production environment with a principal and two agents. We assume that the project output is binary and that the principal can observe the level of agents’ actual eort, but does not know the production function. Identifying conditions that ensure the eciency of the revenue sharing rule, we show that the rule of equal percentage markups can lead to ination of project costs. This result provides an explanation for project cost overruns other than untruthful cost reporting.
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Abstract

We attempt to apply a New Keynesian open economy model to simulate the economic consequences of influenza epidemic in Poland and measure the output loss (indirect cost) related to this disease. We introduce a negative health shock on the supply side of the economy and demonstrate that such a shock – implemented as a reduction in labour utilisation under unchanged labour cost – is not equivalent to negative labour supply shock. As expectational effects may hypothetically play a significant role in determining the economic cost of influenza, we attempt to endogenise the mechanism of epidemic in the model for the rational expectations solution algorithm to take account for the possibility of epidemic. This attempt has failed for the standard SIR model of epidemic and for the standard Blanchard-Kahn-like local solution methods, as the SIR block is only consistent with Blanchard-Kahn conditions under herd immunity of the population. In the deterministic simulation with the number of infected given exogenously, the output loss resulting from influenza-related presenteeism and absenteeism was estimated at 0.004% of the steady state level on average in the period 2000‒2013. The simulated indirect cost in the New Keynesian model has turned out to be lower than the estimates that one could possibly obtain using the human capital approach. The reason for this discrepancy is the demand-oriented construction of the New Keynesian framework, and we treat this result as closer in notion to what the friction cost approach might suggest.
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