Life Cycle Model Research Articles

Life Cycle Assessment and Model Optimization for Sustainable Energy Cross-Border E-Commerce

INTRODUCTION: In an in-depth study of the application of sustainable energy in cross-border e-commerce, a comprehensive assessment and model optimization of its life cycle are conducted to promote the practical application of sustainable development in e-commerce. With the increasing global concern for renewable energy and environmental protection, e-commerce, as an international business model, has attracted much attention in terms of the environmental and social impacts of its sustainability.OBJECTIVES: The aim is to provide scientific assessment methods and effective model optimization strategies to promote the feasibility and sustainability of cross-border e-commerce for sustainable energy.METHODS: A comprehensive life cycle assessment (LCA) model was constructed using the system life cycle assessment (SLCA) methodology by collecting data from various aspects of sustainable energy cross-border e-commerce. The model considers the entire life cycle process from energy production, logistics, transportation, and product manufacturing to final consumption and integrates various factors such as resource utilization, environmental emissions, and social responsibility. Based on the assessment, a series of model optimization strategies are proposed, including suggestions for improving supply chain efficiency, promoting green energy applications, and strengthening social responsibility.RESULTS: This study achieved significant life cycle assessment and model optimization results. In terms of energy use, promoting the application of renewable energy significantly reduces carbon emissions; in terms of supply chain management, optimization leads to an overall efficiency improvement and a reduction in resource wastage; and in terms of social responsibility, the enterprise strengthens employee training and community involvement, which enhances its social image. These results show that sustainable energy cross-border e-commerce can better achieve sustainable development goals through systematic assessment and optimization.CONCLUSION: Life cycle assessment and model optimization provide scientific assessment methods and practical suggestions for sustainable energy cross-border e-commerce. In global sustainable development, the e-commerce industry should actively adopt sustainable energy and minimize its negative impacts on the environment and society by optimizing production and supply chain management. Future research can continue to expand the assessment model and deeply explore the potential of sustainable energy in e-commerce to provide more precise guidance for the industry's sustainable development.

Identifying the primary dimensions of DevSecOps: A multi-vocal literature review

Context:Security as a key non-functional requirement of software development is often ignored and devalued in DevOps programs, with security seen as an inhibitor to high velocity required in DevOps implementation. Hence, the DevSecOps approach as a security-orientated expansion to DevOps, has aimed to integrate security into DevOps implementation by promoting collaboration among development, operation and security teams. DevSecOps is a topical concept and rapidly emerging area of practice in both academic and industrial settings. Objective:We reviewed both the white and grey literature to identify recent researches and practical trends of DevSecOps, aiming to: (a) review, document and analyze the current state of DevSecOps in the existing literature; (b) investigate the application of DevSecOps in Global Software Engineering (GSE) contexts. Method:A Multi-vocal Literature Review on DevSecOps and its global application was conducted, by executing a dual-track strategy including white (104 studies) and grey (43 studies) literature from 2012 to 2021. A Thematic Analysis was performed to identify, synthesize and analyze the themes within data for reporting the MLR results. Results:Through the Multi-vocal Literature Review and Thematic Analysis, this paper identifies five major aspects of DevSecOps (Definitions, Challenges, Practices, Tools/Technologies, and Metrics/Measurement); collects related themes of each aspect; and generates a Challenge-Practice-Tool-Metric (CPTM) model by integrating the themes of the latter four aspects within a lifecycle model. Moreover, an unexplored area relating to the global application of DevSecOps has been identified. Conclusion:Based on MLR results, a CPTM (Challenge-Practice-Tool-Metric) model is built to reveal the current status of DevSecOps. The model provides a breakdown and a broad landscape of DevSecOps, from which researchers and practitioners may select an area of focus to improve their knowledge or practice. With DevSecOps spanning the many stages of the lifecycle, we believe the model will enable emphases and absences such as global aspects to be investigated.Editor’s note: Open Science material was validated by the Journal of Systems and Software Open Science Board.

A synergistic study of policy and literature on rumor governance

Rumor governance is an important guarantee for social stability and public safety. Based on the life cycle and crisis cycle model, this paper conducts a synergistic analysis of China's rumor governance policies and regulations and the core scientific research literature on rumor governance in WOS and CNKI. In this paper, we use the TF-IDF algorithm to count the word frequencies of 326 policy and regulation texts, the Jieba-RoBERTa-Kmeans model to cluster high-frequency keywords, and CiteSpace software and the LLR clustering algorithm are utilized to extract and cluster keywords from 391 documents in the WOS database and from 703 documents in the CNKI database. Based on the synergistic analysis of the life cycle model, it is found that the research on policies and regulations precedes the research on literature, and both are in the period of refinement.Based on the synergistic analysis using the co-occurrence comparison of subject terms in the crisis cycle model, it is found that there is a lack of research in the stages of prevention, monitoring, and governance, and this paper proposes the systematic governance mechanism and strategy for crisis resolution that conforms to the trend of life cycle evolution and is synergistic with policy and literature. This study has only selected Chinese policies and regulations, and the proposed governance strategies have not yet been verified in practice; future research can expand the scope and depth of the study and conduct empirical research and pilot projects.

Low-Carbon Optimal Configuration of Integrated Electricity and Natural Gas Energy System with Life-Cycle Carbon Emission

In response to the challenges of global warming and the development of A low-carbon economy, the integrated electricity and natural gas energy system (IEGES) is known as an important structure for future energy supply; thus, its planning and design must take low-carbon and environmental protection factors into account. Regarding carbon emissions as an optimization criterion, this paper built life-cycle carbon emission models of IEGES components. Then, taking the capacities of the energy resources, storage and conversion units of IEGES as the optimization variables, a multi-objective optimization configuration model was established considering the annual investment operation cost and the life-cycle carbon emissions. The multi-objective model was transformed into a single-objective one by an ε-constraint approach and the polynomial fitting method was employed to obtain the value of ε for obtaining uniformly distributed Pareto sets. Based on the fuzzy entropy weight method and the fuzzy affiliation degree approach, the obtained Pareto sets were ranked and the solution with the highest ranking value was selected as the optimal solution for the original problem. Finally, the configuration schemes were analyzed from the perspectives of economy, carbon emission and renewable energy utilization, and the effectiveness and rationality of the proposed optimization method were verified through MATLAB simulation.

ORGANIZATION OF REAL ESTATE DEVELOPMENT PROJECTS

The considers the field of development, specifically focusing on the organization of project management in development. It is demonstrated that real estate development possesses certain characteristics that directly impact the activities of developers and the organization of development management. The presence of these characteristics creates a unique environment in which developers operate, influencing various approaches, schemes, forms, and models of project development management organization. The purpose of the article is to formulate systematic concepts regarding the forms of organization in development projects. To achieve the goal of forming a comprehensive understanding of organizational mechanisms for managing development projects, the paper examines the organizational environment in which project teams operate and the forms of project management organization in development companies. The paper illustrates that in the project life cycle model, the organizational structure of project management can vary both within individual phases and across projects of different concepts and scales. The management organization during different phases of the project life cycle (PLC) and the organizational structures of development companies during the construction phase have been analyzed. It is demonstrated that contemporary organizations consistently channel their efforts towards improving (developing) the organizational management environment in development and creating conditions for the successful implementation of projects. Therefore, in addition to the value of creating new tangible assets, the project management group (PMG) adds (creates) value through the establishment of a unique organizational environment. The approach to evaluating the values of collaborative work within a project team is demonstrated. The developed organizational environment unquestionably represents a value that the developer additionally acquires along with new development projects. Task: the paper explores the organization of project management groups (PMG) in development; organizational forms of development project management; the organization of project management in development during the construction phase as the most significant; and organizational structures of development companies. Research results: a system application for the organization of development projects’ management has been created. Possible forms of development projects’ organization and elements of the company's organizational structure are analyzed.

Embracing Pure Electric Buses: Vision, Risks and Challenges

In this paper, we mainly focus on the current hot discussion of pure electric public transportation trends. First, we discuss the ecological environment improvement of a city if the original fuel buses are converted to pure electric buses. We use a carbon emission model, an indirect one, and a direct one. Through the quantitative consideration of different factors, the carbon emission model of the whole life cycle of a pure electric bus is finally proposed, and the model is cross-verified by sensitivity analysis. Then, taking Hong Kong as an example, we collected the operation data and cost of public transport in Hong Kong and considered the cost pressure brought by replacing its buses with pure electric buses. We considered acquisition costs, operating costs, operating maintenance and repair costs, and battery replacement costs, etc., combined with government subsidy programs, we obtained the relationship between the relevant replacement costs and the number of replacements. Then, we consider whether our model in Hong Kong, New York, and London can provide reference opinions for replacing pure electric buses in these cities. In addition, with the support of a large number of data, we have formulated a government-funded timetable for the replacement of pure electric buses in three cities within ten years, which has a certain reference value. Finally, considering the current situation of buses in Hong Kong, we propose financial and environmental recommendations to the Transport Department of Hong Kong, as well as future forecasts and prospects.

Identifying environmental impacts linked to the production of plant-based spreads in Peru using life cycle assessment

Plant-based spread products, such as margarine, are made up of a combination of diverse ingredients, many times arriving from different parts of the world. This makes their environmental impact challenging to compute. In Latin America, despite efforts in recent years to enlarge the number of food items that have been analyzed from an environmental perspective, many processed products remain unexplored. In this context, the main objective of the current study was to determine the environmental impacts of a set of five plant-based spread products in Peru using life cycle assessment. For this, primary data were collected from the main margarine producer up to the gate of the agroindustrial plant ready for distribution. Methodological choices, such as allocation, the computation of land use changes (LUCs) or agricultural management variability, were an important subset of variables to be considered in the life cycle modeling and accounted for through scenario and sensitivity analyses. Results demonstrated that greenhouse gas (GHG) emissions related to margarine production in Peru range from 1.66 to 6.00 kg CO2eq per kilogram of product, in a similar range to other studies in the literature. LUCs accounted for the highest contribution to GHG emissions, whereas crude oil extraction, as well as on field fertilizer emissions were the other main contributors. In other impact categories, plant protection agents were relevant in toxicity indicators, fertilization in eutrophication and transport in air quality-related categories. These results constitute a benchmark for the production of plant-based products in Latin America and are useful for attaining cleaner production, as well as for the optimization of ingredients and packaging design.

Not yet another BPM lifecycle: A synthesis of existing approaches using BPMN

ContextBusiness Process Management (BPM) is considered an important management approach that encompasses a set of methods for managing the business processes of an organization. To maximize the benefits of BPM, scholars have conceptualized its steps in schematic diagrams with interrelated phases called BPM lifecycles. As this approach has been established, the phenomenon of perpetual proposition of BPM lifecycles has been observed in relevant literature. This practice obscures what should be relatively straightforward: a consensus among researchers and practitioners regarding the steps that a business process should flow through during its lifecycle. ObjectiveThe aim of this work is to investigate the existing BPM lifecycle models proposed in literature, identify convergences and variations in these models, analyze their core components and locate common patterns that will enable the synthesis of a BPM lifecycle that is conceptualized with Business Process Model and Notation (BPMN), the community de-facto business process modeling notation. MethodTo formalize the research problem and develop the design of a solution, the Design Science Research Process (DSRP) model was adopted. To investigate the perpetual proposition of BPM lifecycles in literature, the authors conducted a Systematic Literature Review (SLR). On whether recurring patterns can emerge from the BPM lifecycles, a normalization process was introduced to homogenize the data and four metrics were used to evaluate the results. The emerging patterns were assembled into a graph that formed the basis for proposing a synthetic BPM lifecycle. ResultsThe outcome of the paper is three-fold: First, the identification of four major inefficiencies of existing BPM lifecycles, namely varying granularity, inconsistent nomenclature, subjective polysemy, and lack of formal conceptualization approaches. Also, a standardized definition of the inclusive steps that exist in the lifecycles by clustering the existing ones in a conceptually systematic manner. Finally, a synthetic BPM lifecycle is conceptualized that systematizes the existing concepts and their interrelations based on a formalized BPMN model in two levels of granularity: a basic version that illustrates the functional and control-flow aspects of the BPM lifecycle and an enhanced version incorporating additionally the resource and data perspectives. ConclusionThis paper proposes a BPMN-based conceptualization of the BPM lifecycle that can facilitate the management of business processes by providing enhanced clarity, improved resource management, and predefined error handling in a BPM initiative. By systematizing the control-flow, data, and resource perspective of the BPM lifecycle, stakeholders can gain a clear understanding of the sequence of steps, the interrelated data flows, and the distribution of work.

Integrating health, nutrition, and environmental impacts of foods: a life cycle impact assessment and modelling analysis of foods in Canada

BackgroundGiven the urgency of transitioning towards sustainable nutrition, dietary shifts that provide co-benefits to human health and the environment are imperative. There is currently no database of the environmental impacts of foods that reflects Canada's unique geographical and agri-climatic context and regional inputs and emissions. To determine sustainable diets, harmonising nutritional considerations with environmental impacts is also essential for an equitable comparison of foods. We aimed to develop a Canadian Food Life Cycle Inventory database and a multidimensional index to enable a joint assessment of the health and environmental impacts of foods in Canada. MethodsThe Canadian Food Life Cycle Inventory database uses life cycle assessment methodology to evaluate environmental impacts. The datasets mirror Canada's food consumption patterns, averaging the spectrum of agricultural practices weighted by domestic production and import shares. The database is structured according to the nomenclature and categorisation of the Canadian Nutrient File. Environmental sustainability is assessed using a cradle-to-grave approach, including indicators such as greenhouse gas emissions, eutrophication, particulate matter, freshwater usage, land use, non-renewable energy consumption, and food loss and waste. Environmental impacts are quantified through an environmental impact score (EIS) assigned to each impact category for a given food. The EIS-nutrition (EIS-N) integrates the evaluation of nutritional quality with environmental impacts using Nutri-Score, a validated food nutrient-profiling tool. The EIS-N is modelled as a ratio of the EIS to the Nutri-Score values. FindingsPreliminary results show the greatest environmental impacts for animal-based foods, particularly beef, in agreement with current literature. Foods with greater nutritional quality also generally show greater environmental sustainability, with some exceptions for particular impact categories. InterpretationThe database and index have potential to serve as powerful tools to support researchers, policy makers, and consumers, harnessing big data to drive efficient food and climate solutions for systems transformation. FundingProvince of Ontario and University of Toronto, CIHR SMART Healthy Cities Training Platform, and University of Toronto's Temerty Faculty of Medicine.

The Heterogeneous Effects of Social Assistance and Unemployment Insurance: Evidence from a Life Cycle Model of Family Labor Supply and Savings

We empirically analyze the heterogeneous welfare effects of unemployment insurance and social assistance. We estimate a structural life cycle model of singles’ and married couples’ labor supply and savings decisions. The model includes heterogeneity by age, education, wealth, sex, and household composition. In aggregate, social assistance dominates unemployment insurance; however, the opposite holds true for married men, whose leisure time declines more than that of their spouses when unemployment insurance is reduced. A revenue-neutral rebalancing of social support away from unemployment insurance and toward social assistance increases aggregate welfare. Income pooling in married households decreases the welfare value of social assistance. (JEL D13, D15, G51, I38, J22, J64, J65)

Development of Virtual Reality for Optical Fiber Splicing Simulation

This study aims to determine the design and evaluation of content and media experts in the development of Virtual Reality for Optical Fiber Splicing Simulation. The research method used is Research & Development with the Multimedia Development Life Cycle (MDLC) model which consists of concept, design, material collecting, assembly, testing, and distribution stages. This Virtual Reality development uses the Unity application in making applications with the Oculus Quest 2 device. The data collection process begins with interviews with educators about the learning that takes place, and the difficulties experienced. At the testing stage, Blackbox Test, Content Expert Test: 1.00 Validity Coefficient, and Media Expert Test: 1.00 Validity Coefficient. Virtual Reality for Fiber Optic Splicing Simulation offers simulation before implementing splicing in real. By taking characteristics of life such as laboratories, educators, and fiber optic practicum tools. Virtual reality can provide situations and conditions for students to practice Optical Fiber Splicing by entering a virtual laboratory in cyberspace. The learning experience in Virtual Reality that provides a sense of immersion in a virtual environment using Full Hand Interaction that applies the Hand Tracking function in Oculus Quest 2. Based on the overall test, the development of Virtual Reality for Optical Fiber Splicing Simulation is feasible to use and distribute to target students.

Life cycle assessment of carbon footprint in dual-phase automotive strip steel production.

As the demand for automotive materials grows more stringent in environmental considerations, it becomes imperative to conduct thorough environmental impact assessments of dual-phase automotive strip steel (DP steel). However, the absence of detailed and comparable studies has left the carbon footprint of DP steel and its sources largely unknown. This study addresses this gap by establishing a cradle-to-gate life cycle model for DP steel, encompassing on-site production, energy systems, and upstream processes. The analysis identifies and scrutinizes key factors influencing the carbon footprint, with a focus on upstream mining, transportation, and on-site production processes. The results indicate that the carbon footprint of DP steel is 2.721 kgCO2-eq/kgDP, with on-site processes contributing significantly at 88.1%. Sensitivity analysis is employed to assess the impact of changes in resource structure, on-site energy, CO2 emission factors, and byproduct recovery on the carbon footprint. Proposals for mitigating carbon emissions in DP steel production include enhancing process gas recovery, transitioning to cleaner energy sources, and reducing the hot metal-to-steel ratio. These findings offer valuable insights for steering steel production towards environmentally sustainable practices.

Bequests and wealth inequality in Japan

This study explores the effect of bequests on wealth inequality in Japan. We construct a heterogeneous life cycle model incorporating the transmission of physical and human capital from parents to their children, particularly bequests transfer and the positive correlation of productivity between them. Our model generates more realistic wealth dispersion in Japan compared to a canonical life cycle model which does not include such capital links. The bequest motives, that is, the desire to leave bequests, increase savings in old age. However, the expectation of receiving bequests in the future leads to a decline in savings when young. Moreover, bequests increase lifetime income, inducing wealth accumulation for achieving more consumption over the life cycle.

Multi-dimensional low-carbon assessments of wind-driven seawater desalination system via hybrid life cycle modeling

Wind-driven desalination is a representative technology of renewable energy that not only alleviates water shortages but also reduces greenhouse gas (GHG) emissions generated by the utilization of fossil fuels. This study examined the GHG emissions from a wind-driven seawater desalination system by using the hybrid input-output life-cycle analysis (IO-LCA) to undertake a comprehensive low-carbon assessment by comparing with traditional thermal seawater desalination systems over the whole life cycle. The findings indicate that the GHG emissions of the wind-driven seawater desalination system are 96.14% lower than those of the traditional system. According to estimations, if reverse osmosis (RO) desalination is driven by wind power technologies at a larger scale, the annual GHG emissions can be reduced by an amount between 7.54E+05 and 3.71E+06 t CO2-eq. Although the construction stage increases the emissions to 55.41% over the whole life cycle, the payback period (Ypp) is about 2.69 years, which means that the level of GHG emissions could be reduced by 25.42% of the level of the traditional systems. Based on the multi-dimensional low-carbon assessment, this study is expected to provide quantitative assessments and policy implications to integrate low-carbon technologies with seawater desalination and promote sustainable development of seawater desalination industries.

Human capital and migration: A cautionary tale

We analyze the impact that the option of migration might have on human capital accumulation. We show that, when the return to education for migrants is lower in the destination than in the origin, the overall incentive to accumulate human capital is reduced as restrictions on migration are relaxed. We use panel data from the Chinese Household Income Project to document that the return to education for rural individuals is lower in urban areas than in rural areas. We then use a difference-in-differences design to show that the 1983 reform that eliminated the strong restriction that existed for rural–urban migration resulted in a reduction of 0.4 years of schooling for rural people in China. Guided by these results, we estimate a life-cycle dynamic discrete choice model of education decisions and circular rural–urban migration in which individuals differ in observable characteristics and unobservable cognitive and non-cognitive skills. We validate the model by showing it is able to replicate the impact estimates from the difference-in-differences specification. Our simulations show that, while it would take a small subsidy (conditional on staying in school) to undo about 40% of the negative effects of the 1983 policy on rural education, the annual subsidy would need to be half of annual earnings to undo the effects entirely.

Environmental Impacts of the Brazilian Egg Industry: Life Cycle Assessment of the Battery Cage Production System.

Brazil stands as one of the world's leading producers of animal protein, ranking sixth in global egg production. However, estimated growth in production demand, along with environmental impacts, represents a potential threat to the sustainability of the food system. Methods for assessing and quantifying the environmental impacts generated by Brazilian egg production remain scarce, lacking current reports on comparative effects or guiding standards. The objective of this study was to conduct a life cycle assessment from cradle to farm gate, adhering to ISO 14040 and 14044 standards, for the battery cage egg production systems and associated products in Brazil, with the aim of supporting and promoting sustainability improvements in the Brazilian egg industry. The entire life cycle modeling and process sustainability analysis were executed using the openLCA software, integrated with the Ecoinvent database. Emissions related to egg production yielded results of 65.06 kg SO2 eq., 27.74 kg N eq., 3086.71 kg CO2 eq., 75,152.66 CTUe, 2.75 × 10-5 CFC-11 eq., and 10,044.68 kg MJ eq. per ton of eggs produced. These findings can serve as comparative benchmarks for future studies and for analyzing data across different egg production systems in Brazil.

Logistics Service Provider Lifecycle Model in Industry 4.0: A Review

Supply chain and logistics management is of tremendous importance for multinational organizations. Logistics Service Providers (LSPs) provide logistics services and smooth logistics operations between suppliers, manufacturers, distributors, and customers. This paper uses a Systematic Literature Review (SLR) to identify the current trends and future developments of LSPs and the underlying (smart) logistics operations connected to the concept of lifecycle management. An SLR review was conducted to identify relevant research papers in the areas of LSPs and logistics lifecycle management. Out of 288 papers analyzed, 81 were identified as highly appropriate for in-depth analysis. The LSP Lifecycle Model (LSLM) was then developed by combining logistics service characteristics and the lifecycle management concept, including Product Lifecycle Management (PLM), Service Lifecycle Management (SLM), and Product Service System (PSS). The LSLM consists of three phases: The Beginning of Life (BOL), the Middle of Life (MOL), and the End of Life (EOL). The LSLM is characterized by three phases, eight criteria, and seventeen sub-criteria. This paper aims to fulfil customer requirements through a product or service in the whole lifecycle of the logistics service provider. The findings further present an adaptable LSLM by focusing on various logistics services and integrating sustainability factors to meet market trends. Logistics cost factors can also be used to evaluate logistics services in the MOL stage. The EOL shows the trend of risk management, evaluation, and decomposition, which is determined by new or re-designed logistics products and services.

Artificial Intelligence (AI) Based Game Development ``Memory Game'' for Training Functions Alzheimer and Dementia Cognitive

Smart games, especially crossword puzzles can be an effective tool in aiding cognitive and physical exercise by stimulating the brain and strengthening brain connections, which can help prevent or slow the progression of Alzheimer’s and dementia. This research aimed to develop a crossword puzzle game into a digital version in Bahasa Indonesia with Artificial Intelligence (AI) features. The benefit of this game product can be used as a cognitive therapy for Alzheimer’s and dementia sufferers. The research method used is game development using the Game Development Life Cycle (GDLC) model with stages of initiation, pre-production, implementation/development, testing, launch, and maintenance. Implementation of digital version using Unity 3D game engine with AI feature of hint generating. This research was carried out for 8 months. Game testing results were carried out by testing the functionality of game features and the results were that all features functioned well. The innovation and importance of this work was to implement the memory crossword puzzle game design into a digital version in Bahasa by implementing artificial intelligence methods for the hints feature. This work will inspire developers to do greater work on Bahasa and implement various features based on AI methods.
 Keywords: digital memory games, artificial intelligence, crosswords, game development

Production forecasting methods for different types of gas reservoirs

Hydrocarbon production in oil and gas fields generally progresses through stages of production ramp-up, plateau (peak), and decline during field development, with the whole process primarily modeled and forecasted using lifecycle models. SINOPEC's conventional gas reservoirs are dominated by carbonates, low-permeability tight sandstone, condensate, volcanic rocks, and medium-to-high-permeability sandstone. This study identifies the optimal production forecasting models by comparing the fitting coefficients of different models and calculating the relative errors in technically recoverable reserves. To improve forecast precision, it suggests substituting exponential smoothing method-derived predictions for anomalous data caused by subjective influences like market dynamics and maintenance activities. The preferred models for carbonate gas reservoir production forecasts are the generalized Weng's, Beta, Class-I generalized mathematical, and Hu-Chen models. The Vapor pressure and Beta models are optimal for forecasting the annual productivity of wells (APW) from gas-bearing low-permeability tight sandstone reservoirs. The Wang-Li, Beta, and Yu QT tb models are apt for moderate-to-small-reserves, single low-permeability tight sandstone gas reservoirs. The Rayleigh, Hu-Chen, and generalized Weng's models are suitable for condensate gas reservoirs. For medium-to-high-permeability sandstone gas reservoirs, the lognormal, generalized gamma, and Beta models are recommended.

Tourism destination development: the tourism area life cycle model

The tourist area life cycle has been in existence for over four decades since its publication in The Canadian Geographer and was described as ‘one of the most cited and contentious areas of tourism knowledge….(and) has gone on to become one of the best known theories of destination growth and change within the field of tourism studies’ It was noted as one ‘Of the most influential conceptual models for explaining tourist, development’. The model was developed primarily from the Product Life Cycle model used in business and management studies and modified to explain the process of development and change that took place in tourist destinations throughout the world. The model has received considerable attention over its life span, but has often been cited from second hand sources or misquoted on many occasions. Its appearance in a non-tourist journal has resulted in it often not appearing in various early literature surveys based on tourism-focused sources and for its first decade access to the original article was limited and difficult, as demonstrated by many requests to the author for copies of the article. Electronic access to journals and libraries have resolved this problem, but its considerable visibility (in excess of 56,000 reads on Research Gate) and use (close to 5000 citations) means that it has possibly entered the realm of tourism myths and become part of accepted dogma in the field of tourism development. This could present problems to those challenging the original concept and introducing alternative or contradictory ideas and propositions, and it is perhaps, appropriate to briefly review the history of the concept.