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].
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.
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.
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.
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.
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.
The model for estimating the whole life costs of the building life cycle that allows the quantification of the risk addition lets the investor to compare buildings at the initial stage of planning a construction project in terms of the following economic criteria: life cycle costs (LCC), whole life costs (WLC), life cycle equivalent annual costs (LCEAC) and cost addition for risk (ΔRLCC). The subsequent stages of the model development have been described in numerous publications of the authors, while the aim of this paper is to check the accuracy of the model in the case of changing the parameters that may affect the results of calculations. The scope of the study includes: comparison of the results generated by the model with the solutions obtained in the life cycle net present value method (LCNPV) for time and financial input data, not burdened with the risk effect; the analysis of the variability of results due to changes in input data; analysis of the variability of results as a consequence of changing the sets of membership functions for input data and methods for defuzzification the result.
Underground spaces having features such as stability, resistance, and being undetected can play a key role in reducing vulnerability by relocating infrastructures and manpower. In recent years, the competitive business environment and limited resources have mostly focused on the importance of project management in order to achieve its objectives. In this research, in order to find the best balance among cost, time, and quality related to construction projects using reinforced concrete in underground structures, a multi-objective mathematical model is proposed. Several executive approaches have been considered for project activities and these approaches are analyzed via several factors. It is assumed that cost, time, and quality of activities in every defined approach can vary between compact and normal values, and the goal is to find the best execution for activities, achieving minimum cost and the maximum quality for the project. To solve the proposed multi-objective model, the genetic algorithm NSGA-II is used.
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.
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.
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.
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.
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.
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.
The issues discussed in the study mainly relate to the costs presented by the structure of positions. This study, on the example of the KGHM Polska Miedź SA mining company (three mining plants), examines the position and cost calculation structure relating to technological works, cost settlement and receivables between branches and mining plants. Cost comparisons were also carried out from the perspective of the organizational structure. The cost centers, registration and settlement of costs in the accounting records, i.e. SAPR3 were highlighted. In the course of the examination, a comparative analysis was carried out aimed at determination of common features and differences between the cost of technological works by their function in the technical cost of manufacturing. As a result of the analysis, it was determined that in the years 2000–2017, the cost structure based on the position function underwent changes. The changes occurred as a result of organizational and technical and geological and mining conditions. The cost analysis allows to identify the directions of specialization of the entity in the future. The basic operating activity of the mines concentrates on extraction. Due to copper extraction in the concession areas, the analysis was to evaluate the costs incurred in the KGHM Polska Miedź SA mining plants.
The corporate cost of capital is used by valuators to discount future flows of income from an entity in order to derive a present-day, forward-looking value of that entity. The cost of capital is therefore determined as the weighted cost of the various sources of funding, being typically equity, debt and preference instruments. The tricky and important part is estimating the cost of equity, which usually needs the application of finance models. The study on the texts on mineral valuation or mineral project evaluation demonstrates that the capital asset pricing model (CAPM) is a general model for estimating the cost of equity. However, according to shortfalls and problems relating to it a relatively similar and simpler model i.e. the single-index market model is proposed. The single index market model is an important tool in contemporary research in finance. Much of the importance of the model follows from its 'beta' parameter which, ideally, measures the sensitivity of returns on a security to changes in a market model. To estimate the cost of equity of the mining and cement companies listed in Tehran Stock Exchange (TSE) The single-index market model is selected because of the shortfalls and problems of the CAPM as well as the lack of commercial services for determining the market premium. The regression analysis as well as the statistical analysis is carried out using Excel spreadsheet. The statistic significance of the model is tested using t and F test statistics. The results showed that the independent variable (the rate of return on the market index) has a genuine effect on the dependent variable (the rate of return for the stock) and there is a statistically significant linear relationship between the two variables at significance level of 5%. Finally, the cost of equity formining and cement companies is estimated 25.0% and 31.0% respectively. Knowing the cost of equity, calculating the discount rate will not be very difficult.
The fact that mines have to be established at the place where they are located without having a chance to choose a location brings out area usage conflicts with areas that need to be protected. In fact, forestlands are most common in these overlapping areas in Turkey. In order to perform mining activities in this overlapping forestlands, mining enterprises in Turkey receive forest land permit fees (FLPF), reforestation fees, rehabilitation fees + security deposit of conformity to the environment (SDCE), and other fees. In order to determine the share of these costs in mining investments and operating costs (OC) and to bring a solution proposal so that these costs do not pose a risk of loss of the investment in the mining enterprises, questions have been asked to mining enterprises within Turkey using the “Survey Monkey” program. The averages of all forest fees determined from the answers are proportioned to the mining investment amounts (MIA) and the annual average OC of each mining company responding to the Survey.
Thus, the distribution criteria of different forest fees that are required to be paid by the mining enterprises in order to carry out mining operations in the forestlands in Turkey and their distribution on the basis of mineral groups were analyzed. In this calculation, it was suggested that all the fees in Turkey should be reduced to a more reasonable degree by suggesting solutions regarding the calculation method envisaged by the FLPF, which has a very high share. Otherwise, the result of these rates shows that the costs of forest land-use for mining stipulated by the legislation in Turkey are quite high compared to other countries, and that the current mining investments can have difficulty in maintaining their economic operability in the presence of these required costs.
This article presents a concept method which aids the forecasting of the reclamation cost in post- rock mining areas. The method may also prove useful in estimating the investment profitability of a mining operation at its planning stage as well as managing a potential Reserve Fund to cover future activities, such as land reclamation. The development of the method consisted in defining a set of basic/typical land reclamation directions and the typical structure of reclamation operations/works, which are based on “statistically stable” values. The estimations included the distribution of the probable cost of these works with respect to the reclamation direction and were calculated on the basis of the analyzed current price lists and historical land reclamation projects. The article proposes a method for estimating the cost structure of multi-directional projects by combining the basic directions. The changeability and predictability of various land reclamation solutions was analyzed in terms of fuzzy logic. A price list was developed, which included unit costs for separate types of reclamation works, independent of their type and scale. The assumed optimal measure involved comparing the cost of individual types of operations to the surface of the reclamation area. As an example, the method was also applied to hypothetical data from a clastic rock mine with a surface of 20 ha, and for the forest, agricultural and forest-agricultural reclamation directions. The forest-agricultural reclamation directions was presented in the proportions of 0.3:0.7.
Geothermal waters are a source of clean energy. They should be used in a rational manner especially in energyand economic terms.
Key factors that determine the conditions in which geothermal waters are used, the amount of energy obtainedand the manner in which cooled water is utilised include water salinity. Elevated salinity levels and the presence oftoxic microelements may often lead to difficulties related to the utilisation of spent waters. Only a few Polishgeothermal facilities operate in a closed system, where the water is injected back into the formation after havingbeen used. Open (with water dumped into surface waterways or sewerage systems) or mixed (only part of the wateris re-injected into the formation via absorption wells while the rest is dumped into rivers) arrangements are morefrequently used. In certain circumstances, the use of desalinated geothermal water may constitute an alternativeenabling local needs for fresh water to be met (e.g. drinking water).
The assessment of the feasibility of implementing the water desalination process on an industrial scale islargely dependent on the method and possibility of disposing of, or utilising, the concentrate. Due to environmentalconsiderations, injecting the concentrate back into the formation is the preferable solution. The energy efficiency and economic analysis conducted demonstrated that the cost effectiveness of implementing the desalinationprocess in a geothermal system on an industrial scale largely depends on the factors related to its operation,including without limitation the amount of geothermal water extracted, water salinity, the absorption parameters ofthe wells used to inject water back into the formation, the scale of problems related to the disposal of cooled water,local demand for drinking and household water, etc. The decrease in the pressure required to inject water into theformation as well as the reduction in the stream of the water injected are among the key cost-effectiveness factors.Ensuring favourable desalinated water sale terms (price/quantity) is also a very important consideration owing tothe electrical power required to conduct the desalination process