Cost Estimation Research Articles

A novel life-cycle analysis approach using pavement performance curves with cost and performance considerations

ABSTRACT The life-cycle duration (TLC) is typically assumed constant in pavement life-cycle analysis. The added scientific value of this paper is that (TLC) is considered a variable parameter to be estimated from the performance curve using a variable terminal condition rating. A variable (TLC) requires using the equivalent annual value (EAV) instead of the net present value for cost estimation. The life-cycle performance (LCP) curve is constructed using two routine maintenance cycles separated by one major rehabilitation action. The time parameters associated with LCP curve are estimated from the inverse performance function based on the initial, present and terminal condition ratings. The equivalent annual cost and performance associated with a particular LCP curve are used to compute cost/performance (C/P) ratio for optimal maintenance and rehabilitation (M&R) plan selection. The EAV represents the costs of two routine maintenance cycles and one major rehabilitation action. Sample results obtained from three case studies have indicated the reliability of the proposed LCA approach in yielding optimal M&R plans. At the project-level, the optimal M&R plan associated with 7 m/km terminal IRI value resulted in (0.949) minimal (C/P) value. However, the optimal M&R plan with 3.25 terminal PSI yielded (1.50) minimal (C/P) value.

Mapping the techno-economic potential of next-generation CSP plants running on transcritical CO[formula omitted]-based power cycles

Although the thermodynamic potential of transcritical/supercritical power cycles running on CO2 mixtures for next generation Concentrated Solar Power plants has been already confirmed in literature, further investigation to assess the actual feasibility of this technology from a techno-economic standpoint is needed. In fact, large uncertainty is found when it comes to the estimation of the CapEx of the power block, and the same can be said for the solar subsystem when higher-than-SoA operating temperature are considered. In this paper, two CSP schemes, with different maximum operating temperatures, are studied: one employing molten salts and another based on solid particles.To overcome the high uncertainty in terms of cost estimation, a two-step analysis is developed: firstly, the CapEx of the entire plant, except for the power block, is calculated assuming correlations from literature. As a result, the minimum power block cost allowing an LCoE lower than a certain target is identified. Secondly, an inverse methodology is applied, setting the power block cost and assessing the minimum CapEx of the solar subsystem. As a result, a map is obtained showing the target CapEx to be accomplished by sCO2+CSP if a clear reduction of the LCoE of this technology is to be achieved.

Retraction Note: Energy financing, energy projects retrofit and energy poverty: a scenario-analysis approach for energy project cost estimation and energy price determination.

Retraction Note: Energy financing, energy projects retrofit and energy poverty: a scenario-analysis approach for energy project cost estimation and energy price determination.

Economic evaluation of hazardous healthcare waste treatment systems

The cost estimation and assessment of healthcare waste treatment systems (HCWTSs) for preventing financial and environmental damage are essential. This work reports economic analyses of treatment of hazardous–infectious waste based on WHO approach in HCWTSS of 43 hospitals in Tehran, Iran. The waste generation rate for total hospital waste in 43 HCWTSS was 4.42 ± 2.77 kg/active-bed/day. The mean of chemical, sharps, infectious, and general wastes in 43 HCWTSS were 13.79 ± 19.71, 30.29 ± 37.46, 336.28 ± 291.31, and 539.6 ± 383.13 kg/day, respectively. Economic analyses proved that general hospitals spent 1.63 times more than specialized hospitals on treating hazardous–infectious waste per year. The annual cost of treating each kilogram of hazardous healthcare waste in studied HCWTSS was 0.3 dollars. A range of total annual costs in 43 HCWTSS was limited to 7.9–118 thousand dollars. The results of ANOVA test demonstrated that the age and performance levels of hospitals significantly affect the annual capital and operating costs, respectively. Hence, improving recycling knowledge and increasing source-separated recycling should be considered to control the costs in HCWTSS. The results of this work have implications for the hospital managers in especially developing countries to evaluate previously unknown economic analyses and policies and take action to control wasted costs in HCWTSS.

Developing a cost-predictive model for hospital construction projects

ABSTRACT Hospital construction projects require the integration of innovative technologies, making them complex and challenging to estimate accurately. Without reliable guidelines, lists of considerations, or predictive models, decision-makers may choose an unsuitable contractor, leading to cost overruns and project delays. This research used quantitative and qualitative methods, including expert opinions and focus groups, to address this issue and identify critical factors affecting cost estimation in hospital construction. Using multi-regression analysis, historical data was analyzed to establish a cost-predictive model. The study identified 24 factors that determine the most critical criteria affecting the cost estimation of hospital construction. This model can evaluate the estimated direct cost provided to decision-makers in the early stages of the project with over 95% accuracy. The research results can assist professionals in the construction industry in better estimating and managing the costs of hospital construction projects, reducing risks, and improving project outcomes. Key findings indicate that specific components such as site and electrical works show average percentage errors of 8.02% and 5.11%, respectively, highlighting areas prone to cost estimation inaccuracies. This insight directs focus on improving accuracy in these critical sectors, thus further refining cost management strategies for hospital construction projects.

Sustainable materials selection in industrial construction: A life-cycle based approach to compare the economic and structural performances of glass fibre reinforced polymer (GFRP) and steel

In recent years, Glass Fibre-Reinforced Polymers (GFRPs) have shown positive characteristics in terms of both environmental and structural performance, thus proving to be promising materials that can be used in construction to replace traditional materials, such as steel. Regarding environmental performance, the use of GFRP instead of steel can lead to a significant reduction in energy consumption and CO2 emissions, thus containing the environmental impact during their life cycle and contributing to the energy transition. From a structural point of view, the high corrosion resistance and durability of GFRP structures minimise maintenance requirements and greatly extend their lifespan, which can even be considered unlimited, even in terms of reusability.This paper jointly evaluates for the first time the structural performance and economic viability of industrial constructions made from GFRP pultruded profiles. These performances are then compared with that of equivalent steel constructions. This is done through a standardised and exportable model based on life cycle cost (LCC) which is developed in four phases: (1) technical-mechanical properties and structural analysis of the buildings; (2) modelling and cost estimation; (3) evaluation of the LCC indicator; (4) performance comparison of design alternatives.The elaborations show that industrial GFRP structures, while having a higher investment cost than equivalent steel constructions, can guarantee lower maintenance costs in the long run. Interesting quantitative results are: (i) the construction cost of the GFRP structure exceeds that of the steel structure by about 15%; (ii) maintenance costs are much higher in the steel structure than in the GFRP structure, due to the greater susceptibility to corrosion of structural steel; (iii) in relation to its very high durability, the residual value of GFRP structures coincides with the construction cost, while the residual value of steel structures decreases significantly; (iv) the composite structure has a Global Cost less than 26% of that of the steel structure, being the most economically advantageous alternative considering the costs related to the whole life cycle, also confirming itself as a fairer and more accessible alternative.The proposed Life Cycle Cost-based model can find multiple applications in the field of civil engineering as a valid support for the selection between alternative structural materials, useful for the transition to a more circular, just, and sustainable construction industry.

Patients’ health care resources utilization and costs estimation across cardiovascular risk categories: insights from the LATINO study

BackgroundAtherosclerotic Cardiovascular Disease (ASCVD) is a global public health concern. This study aimed to estimate the healthcare resource utilization (HRU) and costs stratified by cardiovascular disease (CVD) risk categories using real-world evidence, in a regional population in Portugal.MethodsThis is a retrospective observational study, using data from Electronic Health Records between 2017 and 2021. Patients aged ≥ 40 years, and with at least one general practitioner (GP) appointment in the 3 years before 31st of December 2019, were included. CVD risk categories were determined based on 2021 ESC prevention guidelines. HRU encompassed hospital data (hospitalizations, outpatient and emergency room visits) and GP appointments. Total direct costs per patient were calculated based on the reference cost of the Portuguese legislation for payment methodology on Diagnosis-Related Groups (DRGs).ResultsAnalysis of 3 122 695 episodes, revealed consistent HRU and costs across the five years. Very high-risk patients, showed higher HRU, particularly in hospital admissions. Costs tended to rise with higher CVD risk level. Very high-risk patients with ASCVD had higher costs for hospital admissions, while low-to-moderate risk patients had higher costs for GP visits. Despite a smaller proportion, very high-risk patients with prior ASCVD represent the highest costs per patient across healthcare settings (from 115€ in emergency visits to 2 673€ in hospitalizations), followed by very high-risk patients without prior ASCVD (ASCVD-risk equivalents).ConclusionThis study revealed a substantial HRU and costs by patients with very high CVD risk, particularly those with prior ASCVD. Moreover, ASCVD-risk equivalents emerge as notable consumers, emphasizing the importance of risk assessment and preventive measures in cost-effective management of these patients.

Cost of a Healthy Diet: A Population-Representative Comparison of 3 Diet Cost Methods in Canada

BackgroundDifferent food price sources and dietary assessment tools may impact the estimation of diet costs and hamper our understanding of the relationship between diet costs and dietary intakes. ObjectivesWe aimed to investigate the effect of 3 diet cost derivation methods, with increasing numbers of food prices and geographic specificity, holding consistent the dietary assessment tool, on the estimation of diet costs overall and by food group. MethodsWe matched 24-h dietary recall data from the 2015 Canadian Community Health Survey-Nutrition (CCHS-N) to food price data from 3 Canadian Consumer Price Index (CPI) food price lists; national short list, national long list, and provincial long list. We compared the daily ($/day) and energy-adjusted ($/2000 kcal) diet costs overall and by food groups for the overall population (4+), children (4–18), and adults (19+). ResultsThe proportion of dietary intakes (grams) that were covered by CPI prices significantly increased from the national short list to the national long list but did not significantly differ from the national long list to the provincial long list. The national short list resulted in the highest daily and energy-adjusted diet costs overall. No difference in diet costs was noted between the national and provincial long lists. Diet costs for 4 food groups—additions, sweets, fruits, and vegetables, which were poorly covered by the national short list—significantly differed using the national and provincial long lists. All 3 diet cost methods were significantly correlated with energy intakes; however, a strong/very strong correlation was detected for children, and a weak/moderate correlation for adults. ConclusionsThe choice of food price data may introduce bias in the diet cost estimate, as well as limiting our understanding of how individuals allocate their diet costs. Refinement of diet cost estimation methodology and measures can strengthen future studies of how consumers allocate their purchases to their diets.

Challenges in Applying System Dynamics to Address Scoping and Estimating Problems

System dynamics (SD) is a fundamental model that facilitates research by defining and modeling a project’s scope and estimation. Scoping and estimation is a set of approaches that ensure engineering managers that a project’s accuracy and cost estimation are properly specified and mapped. Engineering management’s primary project planning responsibilities include project scoping and estimating. Insufficient project scoping and estimation criteria significantly fail the project plan. The study authors collaborated with five distinctive journal institutions to address project scoping and estimation challenges. The authors thoroughly analyzed one core research issue and five secondary research questions from each article. In terms of core issues, most project managers dislike SD modeling because of its complexity, especially if they lacked engineering, programming, mathematical analysis, or IT expertise. The first secondary question revealed that project managers’ awareness of scoping and estimating problems ranges from 78.3333% to 91.6666%. The secondary question revealed that 83.3333% to 90% of managers are familiar with SD, which can help resolve scoping and estimation issues in project management. The third secondary question showed that 83.3333% to 91.6666% of managers are aware of SD during the project’s scoping and estimating phases. The fourth secondary question found that 83.333% to 91.6666% of managers can use mathematical equations and programming for SD design during the scoping and estimating phases. The authors developed a novel SD scoping and estimating model since the last question indicated that there were no downloadable models from the five journals.

WP6.1 - A survey of the estimated cost of surgical consumable items within Ear, Nose, Throat departments

Abstract Aims Studies suggest that practitioners lack knowledge on cost of consumables and fail to appreciate the financial consequences of waste. We aimed to investigate this claim amongst ENT practitioners. Methods An online questionnaire, requiring cost estimations for 20 consumable items, was distributed to London ENT departments. Each item’s actual cost was compared with the average, median and interquartile range of the estimated price. An estimate was deemed ‘correct’ if it was within 20% of the actual price. Results 10.65% of all estimations were ‘correct’. There was no correlation between job role and cost-estimation accuracy. The most accurately estimated item was ‘fenestrated sterile drape’ (24.4%), the least was ‘1L bag of IV normal saline’ and ‘package of sterile sponges’ (0%). Conclusions We found poor cost appreciation of consumables amongst ENT surgeons. This could serve as a catalyst for the inclusion of health economics in specialty training curricula, improving cost-awareness.

Cost estimation of Non-CO2 greenhouse gas emissions reduction- A bottom-up analysis of coal-bed methane extraction and utilization in Shanxi, China

This paper analyzes the synergistic effect of coal-bed methane (CBM) extraction and utilization on greenhouse gas (GHG) emissions reduction in Shanxi Province. Using data from a survey of 87 CBM extraction firms and 61 CBM utilization firms, we draw abatement cost curves of methane emission reduction with the "Conserved Supply Curve (CSC)." Our findings show large diversity among the methane abatement costs of extraction firms, meanwhile cost diversity in the extraction step is mainly due to differences in extraction technologies, rather than mine types. Power generation is the main utilization option for CBM, with much smaller abatement cost diversity than in the extraction step. Most utilization projects are established near CBM sources, with small-scale equipment supplied by domestic vendors. We suggest Shanxi could introduce a carbon pricing mechanism to further encourage CBM extraction and increase its scale. Promoting technology standardization can reduce cost diversity among extraction firms, while developing CBM purifying firms can create standardized products and break the strong integration of extraction and utilization. Strengthening CBM transportation infrastructure can form a competitive market with multi-source supply upstream and efficient transportation downstream. Promoting joint research and development for domestic CBM utilization equipment can also improve its scale.

An innovative bio-inspired Aquila technique for efficient solution of combined power and heat economic dispatch problem

In the field of power systems, the optimization challenge of combined heat and power units economic dispatch (CHPUED) holds immense importance. This study presents an improved Aquila optimization technique (IAQT) that effectively tackles the CHPUED. The primary objective of the enhanced IAQT model is to minimize the overall cost of power generation in CHP systems while satisfying demand and operational constraints. However, to achieve more accurate cost estimations and avoid suboptimal solutions, it is crucial to consider transmission losses in the optimization model. By incorporating transmission losses, the IAQT algorithm can allocate power generation resources more effectively, leading to improved system efficiency and reduced operational costs. The proposed IAQT algorithm addresses the limitations of the standard AQT and introduces novel features to enhance its search capabilities. One key limitation of the standard AQT is its heavy reliance on the best solution found during optimization. To overcome this drawback, the enhanced IAQT model eliminates the dependency on the best solution and enables a more thorough exploration of the search space. Moreover, the algorithm incorporates specific limitations and constraints for each dimension of the newly generated solutions, ensuring their feasibility and validity. The standard AQT and proposed IAQT are tested on CEC 20 benchmark functions. Moreover, the proposed approach is extensively evaluated through experimentation and testing on various scenarios, including 7–48-unit and large 96-unit systems with/without losses. Furthermore, the overall costs for the 7 unit-system are considered including the reserve constraint. The results exhibit the remarkable performance and efficiency of the enhanced IAQT model, outperforming the standard version and several previously reported results. This validation underscores the significant contribution of the study in addressing the CHPUED and highlights its potential for real-world applications.

International trade of green hydrogen, ammonia and methanol: Opportunities of China's subregions

Global initiatives to reduce carbon emissions are stimulating the demand for green hydrogen, ammonia and methanol. By 2023, the total low-carbon hydrogen production capacity from announced projects worldwide is projected to reach 38 million tonnes. China is experiencing a surge in green hydrogen projects, with a growing number targeting international markets in addition to domestic demand. This study delves into a systematic modeling analysis to uncover the pivotal roles that China's subregions can play in shaping the future global trade of green hydrogen, ammonia, and methanol. Utilizing a dynamic programming model, complemented by an array of supply chain models for detailed cost estimations, the study highlights the unique advantages and vast potential of subregional engagement in both domestic and international trade. Furthermore, the research explores the essential infrastructure demands and assesses the impact of renewable energy costs and policy shifts on the evolving trade landscape.

Radial Basis Function (RBF) and Multilayer Perceptron (MLP) Comparative Analysis on Building Renovation Cost Estimation: The Case of Greece

Renovation of buildings has become a major area of development for the construction industry. In the building construction sector, generating a precise and trustworthy cost estimate before building begins is the greatest challenge. Emphasizing the value of using ANN models to forecast the total cost of a building renovation project is the ultimate objective. As a result, building firms may be able to avoid financial losses as long as there is as little discrepancy between projected and actual costs for remodeling works in progress. To address the gap in the research, Greek contractors specializing in building renovations provided a sizable dataset of real project cost data. To build cost prediction ANNs, the collected data had to be organized, assessed, and appropriately encoded. The network was developed, trained, and tested using IBM SPSS Statistics software 28.0.0.0. The dependent variable is the final cost. The independent variables are initial cost, estimated completion time, actual completion time, delay time, initial and final demolition-drainage costs, cost of expenses, initial and final plumbing costs, initial and final heating costs, initial and final electrical costs, initial and final masonry costs, initial and final construction costs of plasterboard construction, initial and final cost of bathrooms, initial and final cost of flooring, initial and final cost of frames, initial and final cost of doors, initial and final cost of paint, and initial and final cost of kitchen construction. The first procedure that was employed was the radial basis function (RBF). The efficiency of the RBFNN model was evaluated and analyzed during training and testing, with up to 6% sum of squares error and nearly 0% relative error in the training sample, which accounted for roughly 70% of the total sample. The second procedure implemented was the method called the multi-layer perceptron (MLP). The efficiency of the MLPNN model was assessed and examined during training and testing; the training sample, which made up around 70% of the overall sample, had a relative error of 0–7% and a sum of squares error ranging from 1% to 5%, confirming specifically the efficacy of RBFNN in calculating the overall cost of renovations.

CONSENSUAL TERMS MODIFYING CONTRACTUAL LIABILITY IN THE LIGHT OF UAE LAW: A COMPARATIVE STUDY WITH FRENCH LAW

Background: In the context of UAE law, this study explores the legitimacy and application of terms that modify contractual liability, drawing a comparative analysis with French law. Contractual terms are essential in shaping agreements, reflecting the parties' expectations and strategies for managing future risks. Since the 19th century, these terms have evolved significantly due to industrial growth and an increase in civil liability disputes. They are designed to limit or exclude a party's liability in the event of a contract breach, offering a mechanism for risk management and economic cost estimation. The paper differentiates between terms that directly address liability and those pertaining to the initiation of liability lawsuits. It examines various clauses, including guarantee clauses, terms that reduce liability, and penal clauses that establish fixed compensation amounts to incentivise contract performance. Additionally, contemporary legal frameworks, including both French and UAE laws, increasingly impose restrictions on contractual freedom to protect vulnerable parties, such as consumers and employees, by prohibiting certain terms and granting judges the authority to invalidate unfair clauses. The study analyses UAE legal texts in comparison with French jurisprudence to clarify the UAE legislator's perspective on the legitimacy of terms. Methods: This study aims to conduct a comparative analysis of Emirati and French laws on modifying contractual liability by analysing primary and secondary sources such as legal texts, judicial decisions, and commentaries. It examines legislative approaches and judicial interpretations, aiming to identify similarities, differences, and areas for UAE legal reform. Inductive reasoning is used to derive broader principles, assessing the effectiveness and fairness of both legal frameworks and considering key differences and guiding principles. Results and conclusions: To define the parties' rights and responsibilities, the parties must agree upon clear and explicit terms that define the damage scope, compensation limits, and exceptions to the contract. Even though these terms are common and regulated, the courts play a significant role in interpreting them, posing legal challenges when unclear. In the UAE, the Civil Transactions Law permits such terms under contractual freedom but lacks clarity on their legality, leaving judicial discretion under Article 206. Other UAE laws explicitly invalidate these terms, aligning with international standards. Post-2016, French law also invalidates terms that remove essential obligations. It is recommended that the UAE legislator clarify its stance on these terms within civil transactions, aligning with other UAE laws, to clearly specify what conditions are acceptable.

Direct Variable Cost Comparison of Monitored Anesthesia Care Versus Wide Awake Local Anesthesia No Tournique Carpal Tunnel Release: A Time-Driven Activity-Based Costing Analysis

Time-driven activity-based costing (TDABC) provides a more accurate and granular estimation of direct variable costs compared with traditional accounting methods. This study used TDABC to quantitatively compare the same-day facility costs of open carpal tunnel release (CTR) performed under monitored anesthesia care (MAC) versus wide awake local anesthesia no tourniquet (WALANT). We retrospectively identified 474 unilateral CTR (182 MAC and 292 WALANT) performed at an orthopedic specialty hospital between 2015 and 2021. Itemized facility costs were calculated using a TDABC algorithm. Patient demographics, surgical characteristics, and itemized costs were compared between those treated under MAC (MAC-CTR) and WALANT (WALANT-CTR). Multivariable regression was performed to determine the independent effect of MAC on true facility costs. Total facility costs were $170 higher in MAC-CTR compared with WALANT-CTR ($652 vs $482). Monitored anesthesia care-CTR cases had higher personnel costs ($537 vs $394), likely because of higher surgery personnel ($303 vs $185) and postanesthesia care unit personnel costs ($117 vs $95). Monitored anesthesia care-CTR cases also had higher supply costs ($119 vs $81). When controlling for demographics and comorbidities, MAC-CTR was independently associated with an increase in personnel costs by $150.65 (95% CI, $131.09-$170.21), supply costs by $24.99 (95% CI, $9.40-$40.58), and total facility costs by $175.66 (95% CI, $150.18-$201.09) per case. Using TDABC, MAC-CTR was found to be 35% more costly to the facility compared with WALANT-CTR. Notably, WALANT-CTR facility costs presented here do not include additional cost savings from anesthesiologist service fees or preoperative laboratory clearance required for MAC-CTR surgeries. To reduce costs related to CTR surgery, greater efforts should be made to reduce the number of intraoperative personnel and maximize the use of WALANT-CTR in an outpatient setting. Economic and Decision Analysis II.

Fast forward problem for adiabatic quantum dynamics: Estimation of the energy cost

Fast forward problem for adiabatic quantum dynamics: Estimation of the energy cost

Estimating Road Construction Costs with Explainable Machine Learning

A preliminary estimation of construction costs is a crucial aspect of any civil engineering project. This paper introduces a framework for estimating construction costs that ensures both accuracy and explainability. The approach utilizes six machine learning models and Shapley additive explanations.

The Cost of Unhealthy Days: A New Value Assessment.

For-profit companies addressing disparities in social determinants of health (SDOH), also known as SDOH Industry companies, often lack member-level claims data to evaluate their organizational interventions. Health-related quality of life (HRQOL) measures, such as the Centers for Disease Control and Prevention's Healthy Days Measure, offer a unique proxy metric to evaluate impact. This retrospective study sought to explore the association between self-reported physically and mentally unhealthy days with health care costs among a Medicare Advantage (MA) population. A cross-sectional study of MA members receptive to a companion care program, and thus likely to have unmet social needs, was conducted. The analysis included members with recorded baseline unhealthy days and complete claims data (n = 2,354). Least squares regression analyses were performed to determine the relationship between baseline medical costs, physically unhealthy days, and mentally unhealthy days. A review of Major Diagnostic Categories (MDCs) was also included to elucidate the strength of the Healthy Days Measure as an indicator of the burden of health conditions. Each additional unhealthy day reported was associated with an increase in 30-day medical costs of $60 and $34 for physically and mentally unhealthy days, respectively. Unhealthy days and costs increased with an increasing number of MDCs. Compared with previous studies linking unhealthy days and health care expenditure, these data reveal the potential for even higher savings by reducing the number of unhealthy days in a high-risk population. This evidence supports using unhealthy days as a HRQOL measure and as an important tool for cost estimations.

Model-free stabilization via Extremum Seeking using a cost neural estimator

In this paper, a fully model-free architecture for vertical stabilization of thermonuclear plasmas in tokamak experimental reactors is presented. For the first time, an Extremum Seeking control algorithm is combined with neural networks to estimate the Lyapunov function to be minimized, resulting in a fully data-driven control architecture. The performance of different neural networks are compared. Specifically, Multilayer Perceptrons and Extreme Learning Machines are considered. The proposed architecture is tested in simulation to show that it can counteract relevant plasma disturbances, resulting in a significant improvement in terms of the achievable operative space compared to the Extremum Seeking algorithm, which still relies on model-based cost estimator.