Simple Spreadsheet Model Research Articles

Using ARIMA Model to Forecast Electricity Load in Jordan

Objectives: This study aims to forecast the daily peak electricity load in Jordan using a dataset of hourly peak load data for the period from January 1, 2010, to December 31, 2022, compiled by the National Electric Power Company (NEPCO). Methods: This study employs the Seasonal Autoregressive Integrated Moving Average (SARIMA) model to make forecasts. The data exhibits an upward trend, seasonality, and non-constant variance. To address these features, the SARIMA model is used to account for the trend and seasonality, while a Box-Cox transformation is applied to manage the non-constant variance. Results: Following the standard Box-Jenkins methodology (identification, estimation, diagnostic checking, and forecasting) and utilizing the “(auto.arima)” function in the RStudio software package, the resulting SARIMA model is ARIMA(1,0,1)(2,1,2)[7]. This model is used to forecast 7 future values of the electricity load. The Mean Absolute Percentage Error (MAPE) and the Root Mean Square Error (RMSE) values, as measures of forecast accuracy, support the precision of our forecasts. Conclusion: Based on empirical results, electricity companies in Jordan are encouraged to use time series models for forecasting electricity loads instead of relying on simple spreadsheet models.

Modeling benefits and tradeoffs of green infrastructure: Evaluating and extending parsimonious models for neighborhood stormwater planning

Green infrastructure is often proposed to complement conventional urban stormwater management systems that are stressed by extreme storms and expanding impervious surfaces. Established hydrological and hydraulic models inform stormwater engineering but are time- and data-intensive or aspatial, rendering them inadequate for rapid exploration of solutions. Simple spreadsheet models support quick site plan assessments but cannot adequately represent spatial interactions beyond a site. The present study builds on the Landscape Green Infrastructure Design (L-GrID) Model, a process-based spatial model that enables rapid development and exploration of green infrastructure scenarios to mitigate neighborhood flooding. We first explored how well L-GrID could replicate flooding reports in a neighborhood in Chicago, Illinois, USA, to evaluate its potential for green infrastructure planning. Although not meant for prediction, L-GrID was able to replicate the flooding reported and helped identify strategies for flood control. Once evaluated for this neighborhood, we extended the model to include water quality through the representation of dispersion and settling mechanisms for two pollutant surrogates—total nitrogen and total suspended solids. With the extended model, Landscape Green Infrastructure Design Model-Water Quality (L-GrID-WQ), we examined benefits, costs, and tradeoffs for different green infrastructure strategies. Bioswales were slightly more effective than other green infrastructure types in reducing flooding extent and downstream runoff and pollution, through increased infiltration and settling capacity. Permeable pavers followed in effectiveness and are suggested where spatial constraints may limit the installation of bioswales. Although green infrastructure supports both flooding and pollution control, small tradeoffs between these functions emerged across spatial layouts: strategies based on only curb-cuts better controlled pollution, while layouts that followed the path of water flow better controlled flooding. By illuminating such tradeoffs, L-GrID-WQ can support green infrastructure planning that prioritizes unique concerns in different areas of a landscape.

Plastic recycling stripped naked - from circular product to circular industry with recycling cascade.

This perspective combines various expertise to develop and analyse the concept of technology cascade for recycling waste plastics with the goal of displacing as much fossil crude oil as possible. It thereby presents archetype recycling technologies with their strengths and weaknesses. It then combines them in various cascades to process a representative plastic mix, and determines how much (fossil) naphtha could be displaced and at which energy consumption. The cascades rely on a limited number of parameters that are fully reported in supplementary information and that were used in a simple and transparent spreadsheet model. The calculated results bust several common myths in plastic recycling, e. g. by prioritizing here recycled volume over recycling efficiency, and prioritizing circular industry over circular products . It unravels the energy cost of solvent-based recycling processes, shows the key role of gasification and the possibility to displace up to 70 % of the fossil feedstock with recycled carbon, a recycling rate that compares well with that aluminium, steel or paper. It suggests that deeper naphtha displacement would require exorbitant amount of energy. It therefore argues for the need to complement recycling with the use of renewable carbon, e. g. based on biomass, to fully defossilise the plastic industry.

A Method for Teaching Overinvestment and Underinvestment Problems in Corporate Finance Courses

One of the most important concepts in corporate finance is agency theory. When the financiers of a firm are not also the managers of the firm, the incentives of different financiers (lenders and owners) often conflict. One of the biggest problems in agency theory is that of overinvestment and underinvestment due to misalignment of shareholder and bondholder incentives. While this problem has many real applications, the underlying concepts frequently seem quite abstract to business students. This paper presents an implementation of a simple numerical spreadsheet model that can clearly illustrate the conflicting incentives of lenders and owners that lead to overinvestment and underinvestment.

Subcutaneous versus endovenous trastuzumab: Real world data from a reference cancer center in Peru.

e12527 Background: HER2 receptor amplification/overexpression is identified in approximately 20% of invasive breast neoplasms; it is characterized by biologically aggressive behavior and worse prognosis compared to HER2-negative tumors. Trastuzumab, a humanized monoclonal antibody, was approved for therapeutic use in HER2-positive breast cancer. The objective of this study is to compare the acquisition costs, costs, and preparation and application times of trastuzumab presentations. Methods: Descriptive and retrospective study in female patients aged 18 years and older with a diagnosis of HER 2 positive early breast cancer who received subcutaneous or intravenous trastuzumab during the years 2019-2021. The study setting was the National Institute of Neoplastic Diseases (INEN)- Lima/Peru. We created a simple spreadsheet model to evaluate costs (expressed in soles). The analysis included the calculation of patient time in the chemotherapy chair, preparation time and treatment administration time. Results: The cost of the subcutaneous presentation was S/4212 and S/4348 for the intravenous presentation. The cost of the complete treatment was S/75816 for the subcutaneous presentation and S/82612 for the intravenous presentation. The cost of the supplies used in the preparation of 18 cycles of treatment for the subcutaneous presentation was S/ 20.7 and for the intravenous presentation S/ 399.96; likewise, the cost of the supplies used in the administration of 18 cycles of treatment for subcutaneous trastuzumab was S/ 34.02 and for the intravenous presentation was S/ 1094.4. The cost of using a chemotherapy chair for 18 cycles for subcutaneous presentation was S/36 and for intravenous presentation S/663. The time used in the application of 1 cycle of subcutaneous presentation was 30 minutes for the first application and 15 minutes for subsequent applications; the time used in the application of each cycle for endovenous presentation was 6 hours for the first application and 2 hours for subsequent applications. The administration of 18 cycles for subcutaneous presentation was S/ 732.45 and for intravenous presentation S/ 6168. The trastuzumab formulation for subcutaneous application is a ready-to-use solution, so it did not generate preparation costs. The preparation time for one cycle of intravenous presentation was 15 minutes and meant an investment of S/693.90 for the preparation of 18 cycles (cost of preparation personnel time). Conclusions: The use of subcutaneous trastuzumab generates less costs associated with an overall savings of 16.36%, its use implies less time for preparation and application, as well as a reduction in patient chair time. These time reductions translate into economic savings, a more efficient use of resources and a reduction in waiting time for appointments in the chemotherapy service and a greater capacity of the oncology service to treat a greater number of patients.

Twilight of Human Judgment

Twilight of Human Judgment

Probability distortion with applications to investment bias

Cognitive bias is thought to play an important role in cost and time overrun in infrastructure projects. It is common for project appraisers to make overly optimistic assessments of project assumptions which, in turn, leads to unrealistic assessments of time and cost. These sorts of appraisals are usually made using simple models that take both technical and economic factors into account. Often, there is some uncertainty in one or more model inputs and these uncertain inputs are represented with probability distributions which are propagated through the model to assess the impact on the output. Cognitive bias, however, can lead to overly optimistic assessments of input distributions, which feeds through to model output, giving an overly optimistic assessment of important indicators. In this paper, methodologies for distorting probability distributions are introduced with the intended purpose of debiasing. These distortions are then demonstrated using a simple spreadsheet model of a hypothetical district heating project.

Must attic ventilation be preserved in energy retrofits?

PurposeThe addition of thermal insulation into attics along with air-tightening of the ceiling plane is a common first step in making homes more energy efficient. Attic ventilation was introduced decades ago on the assumption that air leakage across the ceiling was inevitable and not correctible – this was before the era of spray-applied foams. Often attic ventilation is provided at roof eaves, and ensuring good insulation in their location is critical to avoid cold corners in the rooms below. So may vents be blocked in the course of energy retrofits? The paper aims to discuss this issue.Design/methodology/approachThis study consists of a simple spreadsheet model of attic performance. The model is built using material from ASHRAE Handbook Fundamentals and ASHRAE Standards. It includes: Glaser calculations for temperature, vapor pressure and vapor pressure excess; radiation exchange – solar and sky; buoyancy flow assumption for leakage from indoors; wind flow assumption for leakage from outdoors; and change in attic air RH as assumed indicator of change in sheathing moisture performance.FindingsThe model results show that lowered moisture contributions across air-tightened ceilings may compensate effectively for added insulation (which lowers the attic air temperature) and reduced moisture dilution from attic ventilation.Originality/valueThese results provide support for the policy of allowing attic ventilation reductions that are proportionate to ceiling air leakage reductions as part of weatherization efforts. Given the limitations of the model, continued field observations remain critical.

Incorporating Product Choice into Transit Fare Policy Scenario Models

Customer fare product choices can affect both ridership and revenue, so they are strategically important for transit agencies. Nearly all major agencies offer choices between pay-per-use and pass products, and with each potential fare change, agencies face decisions about whether to modify pass “multiples”—the number of rides needed to “break even” on a pass purchase. However, the simple elasticity spreadsheet models often used to analyze the potential ridership and revenue impacts of fare changes make little or no adjustment for shifts in fare product choices. This paper reviews different options for incorporating product choice into fare policy scenario models, and it presents a ridership and revenue prediction procedure that combines a multinomial logit fare product choice model with the logic of an elasticity spreadsheet model. This combination facilitates evaluation of complex fare changes that are likely to alter fare product market shares while maintaining much of the flexibility and simplicity of a traditional spreadsheet model. Additionally, the proposed model uses only preexisting, revealed-preference automated fare collection data rather than requiring customer surveys. The proposed model is demonstrated using examples at the Chicago Transit Authority (CTA). The CTA experienced a large shift from passes to pay-per-use following a fare change in 2013, illustrating the potential value of accounting for fare product choices in fare scenario evaluation.

Reducing energy poverty through carbon tax revenues in South Africa

How much can poverty be reduced through carbon tax revenue? This study analyses specific programmes, with carbon taxes generating revenues and equivalent spending on programmes to reduce energy poverty. The twin challenges of development and climate change could be addressed in this way in South Africa. A simple spreadsheet model was used to estimate revenue available from a carbon tax, given different tax rates and emission projections. Four programmes to reduce energy poverty were quantified: electrification, extended free basic energy, scaling-up sustainable housing, and subsidising rooftop solar for poor households. Matching carbon revenue with equivalent expenditure, the study found that applying all carbon revenue to a single programme could fund the national budget for electrification. Hundreds of thousands, and up to tens of millions, of households could receive free energy in the form of 5 kg of liquefied petroleum gas every month, as well as better houses that are warmer in winter and with fewer health impacts from indoor air pollution. Carbon revenues could fund at least a few hundred thousand improved homes, or subsidies for at least 100 000 rooftop solar systems per year to poor households. Institutional and other constraints would have to be addressed. Carbon revenue could fully fund all four programmes combined into an integrated strategy, in three of the four scenarios. The results suggested that full funding could be available from 2019 or from 2025, dependent on carbon tax revenue scenario. Energy poverty can be reduced by expenditure of carbon tax revenues.

Turning knowledge into practical benefit: a producer case-study increasing the return on investment in science

The present paper addresses turning knowledge into practical benefit; acknowledging a critical emphasis of the career of John L. Black. Average efficiency of pasture use by beef enterprises in southern Australia is historically ~35%. Two projects established in 2002 showed that the efficiency of pasture use could approach 90% and the conservative rates observed were due to a low adoption of existing knowledge and the perceived risks from intensification. A risk-control management system, ‘More Beef from Pastures’, was developed from these projects, to identify management practices that had the largest impacts on productivity and profitability, the variables that needed to be measured and the upper and lower limits for those measurements to optimise enterprise performance. The principles from that system were incorporated into a productivity and economic spreadsheet model for a beef enterprise near Blayney on the Central Tablelands of New South Wales. The present paper reports the effects on productivity and profitability of several management scenarios, including current practice with 180 breeding cows and progeny sold in the second year after birth; buying and selling steers; making silage; or combinations of steers and silage, to maintain pasture availability between 1200 and 2600 kg DM/ha. Simulations were conducted for rainfall and growth of a phalaris–subterranean clover pasture predicted for the Blayney climate by the Sustainable Grazing Systems model for the Years 2000–2011. The simulations covered eight consecutive years from 2002 to 2009, when mean pasture growth was only 70% of the average. Results from the simulations for current practice were similar to those observed for the enterprise. The simulations showed the importance on profitability of utilising excess pasture in years of high pasture growth. The highest average profitability across years resulted from the scenario involving purchase and sale of steers, but year-to-year fluctuations were large and significant capital was required. The silage and steer-silage scenarios were intermediate in profitability, and depended on initial silage reserves and numbers of breeding cows. The exercise demonstrated that a simple spreadsheet model based on principles of animal nutrition, pasture management and economics was needed to fully evaluate alternative management strategies for practical benefit on existing beef enterprises.

Assessing the Potential Cost-Effectiveness of Microneedle Patches in Childhood Measles Vaccination Programs: The Case for Further Research and Development.

ObjectiveCurrently available measles vaccines are administered by subcutaneous injections and require reconstitution with a diluent and a cold chain, which is resource intensive and challenging to maintain. To overcome these challenges and potentially increase vaccination coverage, microneedle patches are being developed to deliver the measles vaccine. This study compares the cost-effectiveness of using microneedle patches with traditional vaccine delivery by syringe-and-needle (subcutaneous vaccination) in children’s measles vaccination programs.MethodsWe built a simple spreadsheet model to compute the vaccination costs for using microneedle patch and syringe-and-needle technologies. We assumed that microneedle vaccines will be, compared with current vaccines, more heat stable and require less expensive cool chains when used in the field. We used historical data on the incidence of measles among communities with low measles vaccination rates.ResultsThe cost of microneedle vaccination was estimated at US$0.95 (range US$0.71–US$1.18) for the first dose, compared with US$1.65 (range US$1.24–US$2.06) for the first dose delivered by subcutaneous vaccination. At 95 % vaccination coverage, microneedle patch vaccination was estimated to cost US$1.66 per measles case averted (range US$1.24–US$2.07) compared with an estimated cost of US$2.64 per case averted (range US$1.98–US$3.30) using subcutaneous vaccination.ConclusionsUse of microneedle patches may reduce costs; however, the cost-effectiveness of patches would depend on the vaccine recipients’ acceptability and vaccine effectiveness of the patches relative to the existing conventional vaccine-delivery method. This study emphasizes the need to continue research and development of this vaccine-delivery method that could boost measles elimination efforts through improved access to vaccines and increased vaccination coverage.Electronic supplementary materialThe online version of this article (doi:10.1007/s40268-016-0144-x) contains supplementary material, which is available to authorized users.

Examining Errors in Simple Spreadsheet Modeling from Different Research Perspectives

By using a sample of 1st-year undergraduate business students, this study dealt with the development of simple (deterministic and non-optimization) spreadsheet models of income statements within an introductory course on business informatics. The study examined students' errors in doing this for business situations of their choice and found three kinds of errors: errors in selecting variables, errors in initializing variables, and errors in relating variables. This article describes these errors, discusses possible reasons for them from different research perspectives, and gives suggestions for further practice and research. These perspectives dealt with modeling with spreadsheets, spreadsheets as mindtools, and errors in operational spreadsheets. The article is primarily directed to teachers of modeling with spreadsheets, interested in taking a broader view of the subject.

Determining the cost of in-field mitigation options to reduce sediment and phosphorus loss

The Mitigation Options for Phosphorus and Sediment (MOPS) project investigated the effectiveness of within-field control measures (tramline management, straw residue management, type of cultivation and direction, and vegetative buffers) in terms of mitigating sediment and phosphorus loss from winter-sown combinable cereal crops using three case study sites. To determine the cost of the approaches, simple financial spreadsheet models were constructed at both farm and regional levels. Taking into account crop areas, crop rotation margins per hectare were calculated to reflect the costs of crop establishment, fertiliser and agro-chemical applications, harvesting, and the associated labour and machinery costs. Variable and operating costs associated with each mitigation option were then incorporated to demonstrate the impact on the relevant crop enterprise and crop rotation margins. These costs were then compared to runoff, sediment and phosphorus loss data obtained from monitoring hillslope-length scale field plots. Each of the mitigation options explored in this study had potential for reducing sediment and phosphorus losses from arable land under cereal crops. Sediment losses were reduced from between 9kgha−1 to as much as 4780kgha−1 with a corresponding reduction in phosphorus loss from 0.03kgha−1 to 2.89kgha−1. In percentage terms reductions of phosphorus were between 9% and 99%. Impacts on crop rotation margins also varied. Minimum tillage resulted in cost savings (up to £50ha−1) whilst other options showed increased costs (up to £19ha−1 for straw residue incorporation). Overall, the results indicate that each of the options has potential for on-farm implementation. However, tramline management appeared to have the greatest potential for reducing runoff, sediment, and phosphorus losses from arable land (between 69% and 99%) and is likely to be considered cost-effective with only a small additional cost of £2–4ha−1, although further work is needed to evaluate alternative tramline management methods. Tramline management is also the only option not incorporated within current policy mechanisms associated with reducing soil erosion and phosphorus loss and in light of its potential is an approach that should be encouraged once further evidence is available.

An economic model to evaluate the mitigation programme for bovine viral diarrhoea in Switzerland

Economic analyses are indispensable as sources of information to help policy makers make decisions about mitigation resource use. The aim of this study was to conduct an economic evaluation of the Swiss national mitigation programme for bovine viral diarrhoea virus (BVDV), which was implemented in 2008 and concludes in 2017.The eradication phase of the mitigation programme comprised testing and slaughtering of all persistently infected (PI) animals found. First, the whole population was antigen tested and all PI cattle removed. Since October 2008, all newborn calves have been subject to antigen testing to identify and slaughter PI calves. All mothers of PI calves were retested and slaughtered if the test was positive. Antigen testing in calves and elimination of virus-carriers was envisaged to be conducted until the end of 2011. Subsequently, a surveillance programme will document disease freedom or detect disease if it recurs. Four alternative surveillance strategies based on antibody testing in blood from newborn calves and/or milk from primiparous cows were proposed by Federal Veterinary Office servants in charge of the BVDV mitigation programme.A simple economic spreadsheet model was developed to estimate and compare the costs and benefits of the BVDV mitigation programme. In an independent project, the impact of the mitigation programme on the disease dynamics in the population was simulated using a stochastic compartment model. Mitigation costs accrued from materials, labour, and processes such as handling and testing samples, and recording results. Benefits were disease costs avoided by having the mitigation programme in place compared to a baseline of endemic disease equilibrium. Cumulative eradication costs and benefits were estimated to determine the break-even point for the eradication component of the programme. The margin over eradication cost therefore equalled the maximum expenditure potentially available for surveillance without the net benefit from the mitigation programme overall becoming zero. Costs of the four surveillance strategies and the net benefit of the mitigation programme were estimated. Simulations were run for the years 2008–2017 with 20,000 iterations in @Risk for Excel.The mean baseline disease costs were estimated to be 16.04m CHF (1 Swiss Franc, CHF=0.73 € at the time of analysis) (90% central range, CR: 14.71–17.39m CHF) in 2008 and 14.89m CHF (90% CR: 13.72–16.08m CHF) in 2009. The break-even point was estimated to be reached in 2012 and the margin over eradication cost 63.15m CHF (90% CR: 53.72–72.82m CHF). The discounted cost for each surveillance strategy was found to be smaller than the margin, so the mitigation programme overall is expected to have a positive net economic benefit irrespective of the strategy adopted. For economic efficiency, the least cost surveillance alternative must be selected.

Modeling the Mousetrap Car

Many high school and introductory college physics courses make use of mousetrap car projects and competitions as a way of providing an engaging hands-on learning experience incorporating Newton's laws, conversion of potential to kinetic energy, dissipative forces, and rotational mechanics. Presented here is a simple analytical and finite element spreadsheet model for a typical mousetrap car, as shown in Fig. 1. It is hoped that the model will provide students with a tool for designing or modifying the designs of their cars, provide instructors with a means to insure students close the loop between physical principles and an understanding of their car's speed and distance performance, and, third, stimulate in students at an early stage an appreciation for the merits of computer modeling as an aid in understanding and tackling otherwise analytically intractable problems so common in today's professional world.

Impact of Hemoglobin Concentration and Affinity for Oxygen on Tissue Oxygenation: The Case of Hemoglobin-Based Oxygen Carriers

In patients undergoing exchange-transfusion with hemoglobin (Hb)-based oxygen (O₂) carriers (HBOC), native Hb coexists with newly transfused Hb. The two Hb types share the same arterial and venous PO₂, but their affinities for O₂ vary. A simple spreadsheet model is described aiming at evaluating the contribution of each Hb type to the overall O₂ transport characteristics as a function of the batch Hb concentration and O₂ affinity in the HBOC solution, of the fraction of exchange-transfused blood/HBOC, and of the arterial PO₂. This model helps to yield a quantitative estimate of how tissues with high or low O₂ extraction respond to the changes cited above. The results show that the higher the exchange-transfusion ratio, the O₂ transport to tissues becomes progressively impaired. However, this effect is more critical at low batch Hb concentration and high O₂ affinity of the HBOC, especially for tissues/organs with high O₂ extraction, whereas the arterial PO₂ does not appear as critical.

Rain Water Harvesting in Bermuda1

Rowe, Mark P., 2011. Rain Water Harvesting in Bermuda. Journal of the American Water Resources Association (JAWRA) 47(6):1219–1227. DOI: 10.1111/j.1752-1688.2011.00563.x Abstract: Roof-top rain water harvesting is mandated by law for all buildings in Bermuda and is the primary source of water for domestic supply. The average rate at which rain water is harvested at the typical house with four occupants is, however, insufficient to meet average demand. While just over one-third of households have access to supplementary water either from mains pipelines or private wells, the majority rely on deliveries from water “truckers” (tankers) to augment their rain water supply. Assuming a reasonably constant daily demand, there is a linear relationship between the “maximum optimum capacity” of a water storage tank and the size of the rain water catchment area, which depends on the characteristics of the rainfall at a given geographic location. A simple spreadsheet model was developed to simulate tank storage levels for various combinations of catchment area, tank capacity, and demand, with an input of actual daily rainfall data for a study period of nearly three years. It was found that for typical cycles of rainfall surpluses and deficits in Bermuda, the tank capacity which there is no benefit in exceeding — the “optimum maximum capacity”— is 0.37 m3 of storage capacity per 1 m2 of catchment area. Furthermore, it was concluded that many domestic water storage tanks in Bermuda are larger than necessary, especially so where there is a significant imbalance between rain water supply and demand.

Briefing: Spreadsheet analysis of complex masonry structures

When dealing with complex masonry structures, exploration of the potential flow of forces can sometimes be more useful than rigorous analysis. Exploration requires division of the structure into elements, computation of volumes and weights, summation of forces and then the tracing and visualisation of force flow. This briefing note describes how vector algebra and spreadsheets can be used to develop simple interactive spreadsheet models.

Is Denser Greener? An Evaluation of Higher Density Development as an Urban Stormwater‐Quality Best Management Practice1

Abstract: A simple spreadsheet model was used to evaluate potential water quality benefits of high‐density development. The question was whether the reduced land consumed by higher density development (vs. standard suburban developments) would offset the worse water quality generated by a greater amount of impervious surface in the smaller area. Total runoff volume and per acre loadings of total phosphorous, total nitrogen, and total suspended solids increased with density as expected, but per capita loadings and runoff decreased markedly with density. For a constant or given population, then, higher density can result in dramatically lower total loadings than more diffuse suburban densities. The model showed that a simple doubling of standard suburban densities [to 8 dwelling units per acre (DUA) from about 3 to 5 DUA] in most cases could do more to reduce contaminant loadings associated with urban growth than many traditional stormwater best management practices (BMPs), and that higher densities such as those associated with transit‐oriented development could outperform almost all traditional BMPs, in terms of reduced loadings per a constant population. Because higher density is associated with vibrant urban life, building a better city may be the best BMP to mitigate the water quality damage that will accompany the massive urban growth expected for the next several decades.