Modelling trend life cycles in scientific research using the Logistic and Gompertz equations

From Springer Nature via Jisc Publications RouterHistory: received 2021-03-05, registration 2021-08-18, accepted 2021-08-18, pub-electronic 2021-10-09, online 2021-10-09, pub-print 2021-11Publication status: PublishedFunder: Engineering and Physical Sciences Research Council; doi: http://dx.doi.org/10.13039/501100000266; Grant(s): EP/I028099/1Abstract: Scientific topics vary in popularity over time. In this paper, we model the life cycles of 200 trending topics by fitting the Logistic and Gompertz models to their frequency over time in published abstracts. Unlike other work, the topics we use are algorithmically extracted from large datasets of abstracts covering computer science, particle physics, cancer research, and mental health. We find that the Gompertz model produces lower median error, leading us to conclude that it is the more appropriate model. Since the Gompertz model is asymmetric, with a steep rise followed a long tail, this implies that scientific topics follow a similar trajectory. We also explore the case of double-peaking curves and find that in some cases, topics will peak multiple times as interest resurges. Finally, when looking at the different scientific disciplines, we find that the lifespan of topics is longer in some disciplines (e.g. cancer research and mental health) than it is others, which may indicate differences in research process and culture between these disciplines

Generación de escenarios de demanda para productos de innovación

Objetivo: Generar escenarios de demandas simulando el ciclo de vida del producto, cuando este no tiene información histórica o registro de ventas. Métodos: Se utilizan los modelos de difusión de la Curva Logística, Gompertz y Bass, junto con simulación de Montecarlo. Resultados: Se obtienen diferentes escenarios de demanda dado el comportamiento de los parámetros según su distribución de probabilidad. Conclusiones: Se utilizan los modelos de difusión para la generación de escenarios de demanda, como aproximación del potencial de realización de la demanda. Implicaciones prácticas: Los escenarios obtenidos se tomarán como entradas a modelos de programación matemática para la planificación de cadenas de suministro rápidas para productos de innovación.&nbsp

Aplicación del modelo de difusión de Bass para estimar el ciclo de vida de una tienda minorista

This article presents a practical application of Lifecycle estimation using the Bass Diffusion Model in the case of a retail store. The results from the application of the model show that the probability that a person will buy driven by advertising is 5%, whereas the probability of buying based on the recommendation of another customer is 23%. According to the sales Lifecycle results, the store’s monthly sales have stabilized and its market share is near its peak.En el presente artículo se presenta una aplicación práctica para la estimación del ciclo de vida de una tienda minorista a través de la implementación del modelo de difusión de Bass. Al aplicar el modelo se obtiene que la probabilidad que una persona compre impulsado por publicidad es del 5%, mientras que la que compre por recomendación de otro cliente es del 23%. Al analizar el ciclo de venta del negocio se observa que este llegó a un nivel estable de ventas mensuales y se encuentra en auge dentro de la cuota de mercado que se tiene hasta el momento

Forecasting Urban Residential Stock Turnover Dynamics using System Dynamics and Bayesian Model Averaging

Knowing the size of the building stock is perhaps the most basic determinant in assessing energy use in buildings. However, official statistics on urban residential stock for many countries are piecemeal at best. Previous studies estimating stock size an

Probabilistic Forecasting in Decision-Making: New Methods and Applications

This thesis develops new methods to generate probabilistic forecasts and applies these methods to solve operations problems in practice. The first chapter introduces a new product life cycle model, the tilted-Gompertz model, which can predict the distribution of period sales and cumulative sales over a product's life cycle. The tilted-Gompertz model is developed by exponential tilting the Gompertz model, which has been widely applied in modelling human mortality. Due to the tilting parameter, this new model is flexible and capable of describing a wider range of shapes compared to existing life cycle models. In two empirical studies, one on the adoption of new products and the other on search interest in social networking websites, I find that the tilted-Gompertz model performs well on quantile forecasting and point forecasting, when compared to other leading life-cycle models. In the second chapter, I develop a new exponential smoothing model that can capture life-cycle trends. This new exponential smoothing model can also be viewed as a tilted-Gompertz model with time-varying parameters. The model can adapt to local changes in the time series due to the smoothing parameters in the exponential smoothing formulation. When estimating the parameters, prior information is included in the regularization terms of the model. In the empirical studies, the new exponential smoothing model outperforms several leading benchmark models in predicting quantiles on a rolling basis. In the final chapter, I develop a predictive system that predicts distributions of passengers' connection times and transfer passenger flows at an airport using machine learning methods. The predictive system is based on regression trees and copula-based simulations. London Heathrow airport currently uses this proposed system and has reported significant accuracy improvements over their legacy systems

Future of interactive technologies

The concept of interactivity continuously enhances our day-to-day living, allowing us to experience a more convenient and enjoyable life style. Existing analogue technologies such as the internet, mobile phone and satellite have now entered their digital phase, making it possible to increase their capacity for interactivity. The technologies which provide this increased interactivity, namely the internet, mobile and television, are classed as interactive technologies. Television has been successful at marketing, having launched an interactivity interface known as iTV which initially offered superior commercial prospects. However, after a decade, the iTV industry is still quite young and has not reached its full potential. This thesis adopts a range of research methodology with which to forecast the future of interactive technologies, especially interactive TV (iTV). The uptake of new interactive technologies depends on many factors, notably the existing infrastructure in the country of adoption, cultural attitudes to new technology, the radicalism of the technology, social influences and interactions and ease of use, quality and cost. Beyond these, many other significant factors influence the acceptance of interactive technologies, the focus of this thesis is to ascertain the importance of those factors mentioned on technology adoption. This study has adopted technological and judgemental forecasting techniques to predict the future of interactive technologies, following which Cross- Cultural and Technology Acceptance studies were carried out to investigate interactive technology adoption. In the Cross-Cultural study, survey data were collected from the UK, Hong Kong and Pakistan so as to examine cultural factors pertaining to the likelihood of adoption, while Growth Curves were used to model and forecast future levels of adoption. Then technology trends in different countries were collected from the global marketing database Euromonitor. The Growth Curves, applied to a selection of interactive technologies, were evaluated and compared to identify the most useful model with which to forecast the future of interactive technologies. The findings identified the Bass Model, Simple Logistic Model and Gompertz Model as the most suitable models for the purpose, with different models identified as best for different cultures. The Judgemental study established that WWW will be the dominant service provider for financial services such as banking or financial products, while iTV will be the dominant service provider for entertainment. WWW will in fact be the dominant provider for most of the services, followed by iTV and then WAP. It is most likely that WWW, WAP and iTV will exhibit technology convergence in 20 years' time and in all probability will converge into WWW. Further to this the Cross-Cultural study confirmed that there are significant differences between cultures regarding the acceptance of interactive technologies, as it is affected by demographic and social interactions and influences. In addition, the study showed that each interactive technology has its own significant elements which influence its acceptance. Overall, the key elements identified as influencing acceptance of interactive technologies were Knowledge and Confidence, followed by the number of hours the individual spends with his or her family. The Technology Acceptance study identified a technology acceptance model for each interactive technology: WWW, WAP and iTV, which established the factors expected to influence the future growth of the technology. Managing these significant elements will assist further in promoting the growth of interactive technologiesEThOS - Electronic Theses Online ServiceGBUnited Kingdo

Techno-economic analysis and decision making for PHEV benefits to society, consumers, policymakers and automakers

2012 Summer.Includes bibliographical references.Plug-in hybrid electric vehicles (PHEVs) are an emerging automotive technology that has the capability to reduce transportation environmental impacts, but at an increased production cost. PHEVs can draw and store energy from an electric grid and consequently show reductions in petroleum consumption, air emissions, ownership costs, and regulation compliance costs, and various other externalities. Decision makers in the policy, consumer, and industry spheres would like to understand the impact of HEV and PHEV technologies on the U.S. vehicle fleets, but to date, only the disciplinary characteristics of PHEVs been considered. The multidisciplinary tradeoffs between vehicle energy sources, policy requirements, market conditions, consumer preferences and technology improvements are not well understood. For example, the results of recent studies have posited the importance of PHEVs to the future US vehicle fleet. No studies have considered the value of PHEVs to automakers and policy makers as a tool for achieving US corporate average fuel economy (CAFE) standards which are planned to double by 2030. Previous studies have demonstrated the cost and benefit of PHEVs but there is no study that comprehensively accounts for the cost and benefits of PHEV to consumers. The diffusion rate of hybrid electric vehicle (HEV) and PHEV technology into the marketplace has been estimated by existing studies using various tools and scenarios, but results show wide variations between studies. There is no comprehensive modeling study that combines policy, consumers, society and automakers in the U.S. new vehicle sales cost and benefits analysis. The aim of this research is to build a potential framework that can simulate and optimize the benefits of PHEVs for a multiplicity of stakeholders. This dissertation describes the results of modeling that integrates the effects of PHEV market penetration on policy, consumer and economic spheres. A model of fleet fuel economy and CAFE compliance for a large US automaker will be developed. A comprehensive total cost of ownership model will be constructed to calculate and compare the cost and benefits of PHEVs, conventional vehicles (CVs) and HEVs. Then a comprehensive literature review of PHEVs penetration rate studies will be developed to review and analyze the primary purposes, methods, and results of studies of PHEV market penetration. Finally a multi-criteria modeling system will incorporate results of the support model results. In this project, the models, analysis and results will provide a broader understanding of the benefits and costs of PHEV technology and the parties to whom those benefits accrue. The findings will provide important information for consumers, automakers and policy makers to understand and define HEVs and PHEVs costs, benefits, expected penetration rate and the preferred vehicle design and technology scenario to meet the requirements of policy, society, industry and consumers

Future of Interactive technologies

The concept of interactivity continuously enhances our day-to-day living, allowing us to experience a more convenient and enjoyable life style. Existing analogue technologies such as the internet, mobile phone and satellite have now entered their digital phase, making it possible to increase their capacity for interactivity. The technologies which provide this increased interactivity, namely the internet, mobile and television, are classed as interactive technologies. Television has been successful at marketing, having launched an interactivity interface known as iTV which initially offered superior commercial prospects. However, after a decade, the iTV industry is still quite young and has not reached its full potential.This thesis adopts a range of research methodology with which to forecast the future of interactive technologies, especially interactive TV (iTV). The uptake of new interactive technologies depends on many factors, notably the existing infrastructure in the country of adoption, cultural attitudes to new technology, the radicalism of the technology, social influences and interactions and ease of use, quality and cost. Beyond these, many other significant factors influence the acceptance of interactive technologies, the focus of this thesis is to ascertain the importance of those factors mentioned on technology adoption.This study has adopted technological and judgemental forecasting techniques to predict the future of interactive technologies, following which Cross- Cultural and Technology Acceptance studies were carried out to investigate interactive technology adoption. In the Cross-Cultural study, survey data were collected from the UK, Hong Kong and Pakistan so as to examine cultural factors pertaining to the likelihood of adoption, while Growth Curves were used to model and forecast future levels of adoption. Then technology trends in different countries were collected from the global marketing database Euromonitor. The Growth Curves, applied to a selection of interactive technologies, were evaluated and compared to identify the most useful model with which to forecast the future of interactive technologies. The findings identified the Bass Model, Simple Logistic Model and Gompertz Model as the most suitable models for the purpose, with different models identified as best for different cultures.The Judgemental study established that WWW will be the dominant service provider for financial services such as banking or financial products, while iTV will be the dominant service provider for entertainment. WWW will in fact be the dominant provider for most of the services, followed by iTV and then WAP. It is most likely that WWW, WAP and iTV will exhibit technology convergence in 20 years’ time and in all probability will converge into WWW.Further to this the Cross-Cultural study confirmed that there are significant differences between cultures regarding the acceptance of interactive technologies, as it is affected by demographic and social interactions and influences. In addition, the study showed that each interactive technology has its own significant elements which influence its acceptance. Overall, the key elements identified as influencing acceptance of interactive technologies were Knowledge and Confidence, followed by the number of hours the individual spends with his or her family. The Technology Acceptance study identified a technology acceptance model for each interactive technology: WWW, WAP and iTV, which established the factors expected to influence the future growth of the technology. Managing these significant elements will assist further in promoting the growth of interactive technologies