Purchase Capacity Research Articles

Supply chain network optimization for emergency materials considering demand satisfaction

AbstractIn order to effectively guarantee the smooth supply of emergency materials under public health emergencies, first, we predict the number of daily infected people based on the modified SEIRD infectious disease dynamics model and accordingly construct the dynamic demand prediction model of emergency materials so as to catch the change rule of the demand for emergency materials with greater precision. Subsequently, under the premise of demand satisfaction, we optimize the supply chain network of emergency materials and embed two insurance strategies in the supply system in advance: multi‐source purchase and buffer production capacity, to enhance the stability of supply chain by sacrificing part of the cost. Next, a bi‐objective linear programming model based on minimizing system cost and maximizing demand satisfaction is proposed with the intention of realizing the design of emergency materials supply chain network, which balances the risk and cost. Finally, through the analysis of the example, we find that compared with the traditional supply chain network of emergency materials, the total satisfaction rate of the supply chain network optimized by balancing cost and risk is increased by 11.70%, while the cost is increased by only 2.04%, which fully verifies the validity of the optimized design of supply chain network of emergency materials.

Reviewing the affordability and adequacy of affordable housing in urban India: impact of the covid-19 pandemic

PurposeHousing policies in India (last modified in 2017) define “affordable housing” on three main parameters – income of the target group, dwelling unit size and house price to income ratio. The Covid-19 pandemic has questioned the robustness of the defining parameters of affordable housing. This paper aims to study the impact of Covid-19 pandemic on housing affordability and adequacy for the urban poor and highlights how one pandemic has directly challenged the practicality of the affordable housing criteria in urban India.Design/methodology/approachThe study is based on a pilot test conducted through interviews with the consumer group. Furthermore, the affordable housing policies of urban India were studied in conjunction with the pandemic guidelines laid down by the World Health Organization. The consumer responses were analyzed in relation to the policies and guidelines to arrive at the inferences. The secondary case examples of the Dharavi slums in Mumbai and the Savda Ghevra slum resettlement colony in Delhi, along with the findings of the primary survey in the economically weaker section category, are used to formulate the conclusions.FindingsThe pilot test conducted for the target consumer group clearly indicates that (i) the pandemic has severely affected the housing purchase capacity of the target consumer, thereby questioning the “affordability” of housing; (ii) proposed housing solutions are inadequate to enable livability, thereby questioning the “adequacy” of housing; and (iii) proposed housing solutions are inept to accommodate pandemic protocols. The Covid-19 pandemic and the conditions it imposed on the built environment clearly highlight the inadequacy of affordable housing parameters being followed in urban India.Research limitations/implicationsFurther research may be conducted on global best practices in housing, which may advise the housing policies in India.Practical implicationsThe study suggests key areas that need intervention and modification to make the housing policies more robust and effective.Social implicationsThe study explores the social sustainability aspects of housing, which are often considered secondary in policies.Originality/valueBecause housing has a direct bearing on the physical, social and mental well-being of society, it is imperative to find housing solutions that are safe and resilient for a sustainable future. This paper is an original attempt by the author to question and highlight how the current affordable housing solutions adopted in urban India will continue to fail under any external adverse conditions unless modifications are considered in the existing housing parameters.

Investigation of a grid-integrated hybrid energy system for residential and electric vehicle (3-wheeler) loads under schedule grid outage

Due to the global energy crisis and the limited availability of conventional fuels and their reserves in certain areas, the utilization of renewable energy resources is significantly paramount for sustainable development. Grid disruptions have been discovered in areas where demand for electricity has surpassed supply. The purpose of this work is to size a grid-integrated hybrid renewable energy system (HRES) during a scheduled power outage. The HRES model was created to meet the requirements for residential load as well as EV charging load at midnight when the residential load is lower. Using the HOMER Pro software tool, the HRES system is developed to satisfy the residentialload demand of 1940 kWh/day and the electric vehicle (3-wheeler) charging load requirement of 645 kWh/day, respectively. This study examined the effects of grid purchasing capacity and grid scheduling outages on techno-economic and environmental performance. The results show that the most optimal configuration among the various configurations is the PV/WT/Batt with grid-integrated system, which has a COE of 0.0714 $/kWh, an NPC of $1,822,653, and emits 164,812 kg/yr of CO2 into the environment. The optimized system consists of a 377 kW PV module, a 2 kW wind turbine, an 836 kWh battery bank, and a 237 kW inverter. In addition, the impacts of sensitivity of the grid purchase and selling capacity, and the different tariffs on the techno-economic indicators of the HRES have been investigated. The daytime grid outage lowers environmental emissions and increases the renewable contribution compared to the grid outage at night. Reducing the grid’s purchase capacity while increasing the share of renewable energy provides significant advantages. The stand-alone PV/Batt has a higher COE (0.26 $/kWh) than the PV/Batt system (0.072 $/kWh) with the net metering option connected to the national grid.

Pricing method of electric-thermal heterogeneous shared energy storage service

Energy storage system (ESS) has been considered as a pivotal technology enjoying a wide range of applications in different levels of power systems. However, the investment of ESS is still relatively high. Thus, shared energy storage (SES) is consequently recognized as a promising business model. Considering the dynamic virtual energy storage characteristics of heat network, this paper proposes a power-thermal heterogeneous SES model to meet the practical need of participants. Firstly, a quasi-dynamic model of heat energy transport is conducted to analyze the virtual energy storage potential of heat network. Then, the power-thermal heterogeneous SES model is developed to describe the formation mechanism of ESS supply and demand with heat network as the schedulable energy storage resource. Furthermore, a pricing method of electric-thermal heterogeneous SES is proposed. The upper-level problem of it targets at maximizing the benefits of the SES operator, while the lower-level problem aims to minimize the costs of users. Simultaneously, the service price and user purchase capacity can be obtained as optimization variables. Finally, case studies are adapted to verify the rationality and validity of the proposed model.

Factors Influencing Sustainability of Community Based Project in Rwanda: A Case of Imali Project

The main objective of this research study was to determine out the factors influencing sustainability of community-based project in Rwanda with Imali case project implemented by Imbuto Foundation in Gasabo, Kayonza, Huye, Musanze and Rubavu districts. The specific goals of the study are: to find out how community participation affects the sustainability of the Imali project; to find out how resource capacity affects the sustainability of the Imali project; and to find out how project management expertise affects the sustainability of the Imali project. Descriptive research used for this study, and it used both quantitative and qualitative methods. There were 359 persons in all included in the research, representing 9 different cooperatives. The simple size of 196 people was determined by using Krejcie and Morgan (1970) formula and the stratified random sampling used to allocate and deploy the calculated sample size in nine cooperatives proportionally to the size of each one. These showed that the human (age, education, management skills, population participation), economic (resource, purchase capacity), environment (market, calamity disaster) and greenhouse technology usage.  The results presented in tables, figures and cross tables among others and be analyzed by using the literature reviews and proceed by a conclusion and recommendation to the results obtained assuring that the intended beneficiaries and other relevant parties are set up for success once donor funding wanes. The regression analysis on model summary results that indicate the influence of community participation, community resource capacity and project management skills on sustainability of the Imali project. The results indicated R of .798, R square of 0.636 and adjusted R square 0.630 based on R square it shows that 63.60% of total variation on sustainability of Imali project explained by those factors. ANOVA shows that F=108.441 and p 0.000<0.05 which is set as the standard significance level. This means that the researcher can confirm there is an influence of community participation, community resource capacity and project management skills on sustainability of the Imali project. The management of agricultural cooperatives recommended to establish good and sustainable management that ensure sustainability, autonomy, and independency rather than always waiting the external support. Keywords: Sustainability, Community Based Project, Rwanda.

Millennials’ Online Purchase Intention Towards Consumer Electronics : Empirical Evidence from India

Millennials are those born between 1980 and 2000. They are the first digital generation of the 21st century. Millennials’ ability to see the world through the eyes of the digital lens makes them a unique customer segment. Millennials have a higher purchase capacity compared to their older cohorts. Millennials have become an essential category of customers for marketers compared to other cohorts. The article examined the influence of perceived risk, e-service quality, subjective norms, and trust in the context of online shopping for consumer electronics products by millennials. The conceptual model was developed based on the previous studies to achieve these objectives. Data were collected from 474 digital shoppers from Surat, Ahmedabad, and Vadodara cities of Gujarat. The relationships among the constructs were analyzed by using structural equation modeling. The study results indicated that trust, e-service quality, and subjective norms influenced millennials’ online shopping intention for consumer electronics products. The findings provide significant implications for online retailers to develop millennials’ customer acquisition and retention strategies.

Brand Loyalty at Smartphones Market: Linking Between Brand Passion, Hedonic and Utilitarian Values

This paper summarizes the arguments and counterarguments within the scientific discussion on the factors that influence consumers' brand loyalty to smartphone brands. The main aim of the study is to analyze the relationship between hedonic value, utilitarian value, brand passion, and brand loyalty based on consumers' loyalty at the smartphones market. Accordingly, the study focuses on brand loyalty as a consequence of brand passion and reveals it in a holistic framework as it emphasizes the direct relationship between the two variables. In this context, this study is different from others in literature in a way that it focuses on smartphones, which are at the upper ranks of the technological product category. The fact that this study only deals with mobile phones makes it different and essential as studies on electronic and technological products often focus on the general situation. Researchers used positivist research as a quantitative research design in this study, which deals with factors that influence brand loyalty to smartphone brands. The study universe involves 18-year-old and older consumers with a purchase capacity. In this context, the study sample comprises smartphone users at or over the age of 18. The conceptual model and associated hypotheses are tested with a sample of 330 consumers. Researchers collected the study data with a convenience sampling method with the help of an online survey. In the study, data were analyzed through structural equation modelling. The results demonstrate strong relationships between the two antecedents (hedonic value and utilitarian value) and brand passion and between brand passion and its consequence (brand loyalty). Study results indicate that hedonic value (β=0,506; p<0,001) and utilitarian value (β=0,202; p<0,001) have a positive influence on brand passion. Study results also show that brand passion (β=0,683; p<0,001) has a positive influence on brand loyalty. On the other hand, the study also reveals that brand passion mediates the relationship between hedonic and utilitarian value and brand loyalty. Study results point out that hedonic value, utilitarian value, and brand passion have a positive influence on the development of consumers' loyalty to smartphone brands. Keywords brand loyalty, brand passion, hedonic value, smartphone, utilitarian value

A Comparison of Indirect Watering Devices for Benefiting Newly Transplanted Urban Trees

Three types of indirect watering devices were compared to evaluate their performance and to determine their benefits to newly transplanted river birch (Betula nigra) trees grown in containers with well drained compost in a controlled greenhouse experiment. Two examples of each device type were used to water trees in this study: upright bags, ring bags, and open tubs. Watering device characteristics, including purchase cost, weight, capacity, and drainage times, were measured prior to installing the devices around the trees. Tree stem heights and calipers, along with leaf coverage and leaf water potential, were measured to determine any growth or water stress differences associated with watering treatments. There was substantial variation in costs and drainage times among watering devices, with ring bags being the least expensive and draining water completely during the drainage test. However, there was no evidence that watering devices benefited tree growth, leaf rating, or water stress in comparison with direct watering, with the possible exception of Treegator ring bags, which may have reduced water stress marginally. Although water release from some of the indirect watering devices was much slower than direct watering, water release from all of the devices was completed within ten hours, which is too rapid to reduce the frequency of watering in our experiment. The major benefits of these devices are slower release of water to the soil, with reduced operator time required, and more infiltration into the soil and root zone, which avoids the surface runoff caused by quick hose (direct) watering.

The Role of the New Indian Middle Class in Lok Sabha General Elections 2009 and 2014: A Comparative Study

Indian democracy in the age of globalisation is highly influenced by the demographic transformation in the society. Dispensing with the erstwhile traditional barriers like casteism, religions and languages, the current Indian society is represented mainly by the new Indian middle class. This class is a convergent one with amelioration of the below-middle class people to this class. Obviously there is hierarchy among this class. Sometimes, the upper rung of the middle class is treated as the elites. This class has good purchase capacity and inclination towards a consumerist life-style. This class, therefore, not politically involved throughout the year but politically active and vibrant in its electoral capacity. This class has become a no-negligible in the election results particularly since 2009. In 2014 itself, the new Indian middle class became decisive in 2014 Lok Sabha General Election. Here, it is an attempt to explore a comparative study of the 2009 and 2014 Lok Sabha General Elections in terms of this class being a determinant and decisive factor.

The Economic Feasibility Study of Renewable-Based Fuel Cells with Grid Connection for a Commercial Application

Due to their high cost, limited life cycle, low efficiency, and restricted operating conditions, batteries may not be the most cost-effective method for large scale energy storage. On the other hand, hydrogen-based energy storage, such as in a microgrid system, is incessantly gaining more appreciation as a viable and sustainable alternative. This paper presents the economic feasibility study of renewablebased fuel cells with a grid connection for a commercial application. The Hybrid Optimization Model for Electric Renewable (HOMER Pro) software is used as a platform for simulation given the multidimensional nature in an optimization problem. The proposed model is constrained around financial and technical indicators. The optimal system architecture consists of high penetration of the solar photovoltaic system, a grid power, fuel cell generator, electrolyzer, hydrogen tank, and converter. The Net Present Cost (NPC) is impacted directly by the sensitive analysis of the present and projected costs of components of the optimized system; also, the annual purchase capacity at the grid if scheduled rates option is considered. Considering a purchase capacity of 200 kW, the Photovoltaic system, fuel cells (FC), electrolyzer, hydrogen tank, and the converter are sized respectively for 311 kW, 200 kW, 200 kW, 400 kg and 243 kW. Therefore, resulting in an NPC value of $3 337 185,69; a Levelized Cost of Energy (COE) of $0,1095 per kWh and operating cost of $43 402,38 of the optimized system.

The Role of Housing in the Spatial Distribution of Unemployment in Poland

Labour market and housing problems are an important part of social studies, though spatial analysis of labour market diversification and housing resources are not the dominating subject of studies. The interaction between the place of residence and the place of work is treated in terms of commuting to work, but this aspect does not exhaust the issue. The article is an attempt to answer the question whether a relation exists between the structure of housing and its accessibility and the stable diversification of local labour markets. A necessary condition for permanent migration from a location that does not offer work to that characterised by labour demand, is the accessibility of housing offering acceptable living conditions. The decades‑lasting housing deficit and the efforts to improve the situation relying solely on market mechanisms seem to restrict housing accessibility considerably. To answer this question a model of spatial regressions was construed, based on statistical data aggregated at the district (county) level. The results indicate a considerable role of financial accessibility of housing, in terms of purchase capacity and remuneration in particular districts, in preserving the disparities among local labour markets.

A sustainability comparative assessment of Tunisian organic and conventional olive growing systems based on the AHP methodology

This work aims to assess, in a comparative way, the sustainability of organic and conventional olive growing systems in the Sfax region (Tunisia). This assessment will be undertaken based on I) a multidimensional perspective considering the three classical dimensions of sustainability – environmental, economic and socio-territorial – and II) on an experts’ knowledge approach selecting the adequate criteria of sustainability to compare both systems. The Analytic Hierarchy Process methodology (AHP) was applied as the adequate framework to fulfil the study objectives based on a survey directed with a panel of 20 Experts. Results suggest the need to reinforce the economic performance of organic olive growing production system through political strategies focusing on I) the improvement of the productivity by the implementation of good practices II) the increase of the demand of organic products in the local market, essentially by the improvement of the consumer’s purchase capacity and III) the adoption of a strategic plan to explore new markets.

Ship Acquisition of Shipping Companies by Sale & Purchase Activities for Sustainable Growth: Exploratory Fuzzy-AHP Application

Strengthening sale and purchase (S&P) capacity has become a fundamental requirement for sustainable growth and corporate competitiveness in the modern shipping market. However, there is a lack of research related to S&P and its priority when shipping companies attempt to implement ship acquisition through S&P activities. To fill this gap, this paper conducts an empirical analysis to analyze priority factors during the acquisition of second-hand ships from the perspective of shipping companies. Business criteria are considered to be the most important factors in the analysis of the priority of ship acquisition and investment in shipping companies. To the best of our knowledge, this research is the first exploration covering Korean shipping companies’ ship acquisition through S&P activities. This study is expected to contribute to the better understanding of the role of S&P in ensuring the sustainability of shipping companies and to provide stakeholders with valuable insights.

Human Body Digitalization and Marketing Consequences in the Coming Decades

Human body digitization, in other words “mating with technology, represents a fusion of technologies that shrinks the boundaries of physical, digital and biological world. Throughout history, trade perception has changed significantly, from a mere intermediary to creative activities. Adapting marketing activities and strategy, generated by the technology development of modern society requires in-depth marketing research on client profile, customers’ suggestions as well as their purchase capacity, consumption habits and other matters, which are at the ground of demand and trade policies. The authors consider that the technology incorporated in human body will crucially affect the marketing activities and strategy, during the coming decades. By human body digitalization, for example, marketers can have real-time information about the time clients spent in front of a product, various reactions they might have, their level of satisfaction, and which alternatives they are considering. Human body digitization process will crucially affect industrial companies, which will truly become digital businesses with basic physical products complemented by digital interfaces and innovative data services. These digital businesses will directly work with customers and suppliers in digital industrial ecosystems, which represent a radical change in the fundamentals of today's marketing. It is very likely for many companies that data analysis methods can have a significant influence on decision-making processes over the next decade. The authors conclude that the human body digitalization – by collecting various marketing data on client behavior – will dramatically influence the way of future marketing research, and will inherently lead to radical shifts in the marketing area in the coming decades. More than that, the authors of this futuristic study go ahead with forecasts, saying Human Body Digitization will lead to a complete globalization of the services and products market.

Emissions reductions from expanding state-level renewable portfolio standards.

In the United States, state-level Renewable Portfolio Standards (RPS) have served as key drivers for the development of new renewable energy. This research presents a method to evaluate emissions reductions and costs attributable to new or expanded RPS programs by integrating a comprehensive economic dispatch model and a renewable project selection model. The latter model minimizes incremental RPS costs, accounting for renewable power purchase agreements (PPAs), displaced generation and capacity costs, and net changes to a state's imports and exports. We test this method on potential expansions to Michigan's RPS, evaluating target renewable penetrations of 10% (business as usual or BAU), 20%, 25%, and 40%, with varying times to completion. Relative to the BAU case, these expanded RPS policies reduce the CO2 intensity of generation by 13%, 18%, and 33% by 2035, respectively. SO2 emissions intensity decreased by 13%, 20%, and 34% for each of the three scenarios, while NOx reductions totaled 12%, 17%, and 31%, relative to the BAU case. For CO2 and NOx, absolute reductions in emissions intensity were not as large due to an increasing trend in emissions intensity in the BAU case driven by load growth. Over the study period (2015 to 2035), the absolute CO2 emissions intensity increased by 1% in the 20% RPS case and decreased by 6% and 22% for the 25% and 40% cases, respectively. Between 26% and 31% of the CO2, SO2, and NOx emissions reductions attributable to the expanded RPS occur in neighboring states, underscoring the challenges quantifying local emissions reductions from state-level energy policies with an interconnected grid. Without federal subsidies, the cost of CO2 mitigation using an RPS in Michigan is between $28 and $34/t CO2 when RPS targets are met. The optimal renewable build plan is sensitive to the capacity credit for solar but insensitive to the value for wind power.

The Gay Immigrant and the Use of Spanglish in Ángel Lozada’s No quiero quedarme sola y vacía : A Linguistic Transgression or a Struggle to Assimilate in the Late Capitalist City?

The Gay Immigrant and the Use of Spanglish in Ángel Lozada’s No quiero quedarme sola y vacía:A Linguistic Transgression or a Struggle to Assimilate in the Late Capitalist City? Andrés Aluma-Cazorla ¡ngel Lozada’s No quiero quedarme sola y vacía (2006) is the story of a homosexual from Puerto Rico, linked to the success and failure of the neoliberal mercantilist system during the end of the twentieth century and beginnings of the twenty first century. The presence of Spanglish throughout the novel, more than a characteristic element of a linguistic transgression, is a parody of the protagonist’s struggle to overcome the hostility of New York and to be accepted into the cultural and social environment of his host city through the use of language, without luck. This acceptance can be accomplished by his purchase and debt capacity that grants him access to the goods and services offered by the system and portrayed in New York as the Mecca of consumerism. The only possible visibility offered by the city for him is his credit history. If his credit capacity fades away, he becomes useless, just like many of the underprivileged citizens living in the city. Here, the narrator describes the way New York takes care of its underprivileged citizens. Hurry, hurry, take the A train. Dentro de mí se monta La loca. … Se levanta cuando uno de los homeless apestosos choca contra ella, y angustiada, se fija en lo que le espera: miro a los viejitos montarse en el tren, a veces con andadores y a la gente que no les cede las sillas. … Yo transporto la muerte. … Y de nuevo se enfocaba en las paredes llenas de anuncios: I can live with foot pain, but why should I? Retrato de un pato boricua y un negro: dos buenas razones para hacerse la prueba del VIH y que le recuerda su caso: Como si a los únicos que nos diera SIDA fuera a nosotros los latinos y a los negros. (Lozada 25–26) This passage coincides with what Slavoj Žižek (2008) calls “systematic violence of capitalism” (12). This violence is more extraordinary: violence not proffered by any other direct agent and defined solely in an objective, methodic and anonymous way as the one proffered by ideologies. In that way, the metaphor represented by the A-train of New York summarizes the violent and classist image of the city as a body transporting its waste through its entrails. These people, viewed by the city as waste, seem to be on their way to be eliminated and are represented as the most marginal elements of its society: the elderly, the beggars, the sexual, ethnic and racial minorities, and the sick, who also are mentioned in the dominant discourse of AIDS advertisements, a discourse that describes “Afro-Americans, female and male prostitutes, bisexuals and gays, drugs consumers and immigrants as the causes of the propagation of HIV” (La Fountain-Stokes 2009: 46). Lozada does not leave in this novel any open space for a vindication of his sexual freedom. He does not propose a transgression to the system in which he is forced to live. For La loca, New York is only a monster, which condemns its marginal and underprivileged inhabitants to being isolated and meaningless, being forced to disappear out of the glamour of the city by getting inside of it, or in its outskirts destined for them. Therefore, one can understand the magnitude [End Page 364] of La loca’s physical and psychological degradation when he discovers that his only empowering instrument, his credit history, is fading away, sentencing him to stay sola y vacía in the once utopic city of New York. Andrés Aluma-Cazorla University of Illinois–Chicago WORKS CITED La Fountain-Stokes, Lawrence M. (2009). Queer Ricans: Cultures and Sexualities in the Diaspora. Minneapolis: U of Minnesota P. Print. Google Scholar Lozada, á ngel. (2006). No quiero quedarme sola y vacía. San Juan: Isla Negra. Print. Google Scholar Žižek, Slavoj. (2008). Violence: Six Sideways Reflections. New York: Picador. Print. [End Page 365] Google Scholar Copyright © 2014 American Association of Teachers of Spanish and Portuguese, Inc.

Technical and financial analysis of combined cycle gas turbine

This paper presents technical and financial models which were developed in this study to predict the overall performance of combined cycle gas turbine plant in line with the needs of independent power producers in the liberalized market of power sector. Three similar sizes of combined cycle gas turbine power projects up to 200 Megawatt of independent power producers in Pakistan were selected in-order to develop and drive the basic assumptions for the inputs of the models in view of prevailing Government of Pakistan?s two components of electricity purchasing tariff that is energy purchase price and capacity purchase price at higher voltage grid station terminal from independent power producers. The levelized electricity purchasing tariff over life of plant on gaseous fuel at 60 percent plant load factor was 6.47 cent per kilowatt hour with energy purchase price and capacity purchase prices of 3.54 and 2.93 cents per kilowatt hour respectively. The outcome of technical models of gas turbine, steam turbine and combined cycle gas turbine power were found in close agreement with the projects under consideration and provides opportunity of evaluation of technical and financial aspects of combined cycle power plant in a more simplified manner with relatively accurate results. At 105 Celsius exit temperature of heat recovery steam generator flue gases the net efficiency of combined cycle gas turbine was 48.8 percent whereas at 125 Celsius exit temperature of heat recovery steam generator flue gases it was 48.0 percent. Sensitivity analysis of selected influential components of electricity tariff was also carried out.

Housing Finance in Central America: What is Holding it Back?

This paper surveys housing finance in Costa Rica, El Salvador and Panama. The development of a secondary mortgage-backed securities market in Costa Rica is very limited despite a broad legal framework, while in El Salvador it is nonexistent and in Panama has not grown due to high liquidity. In Costa Rica's subsidy policy, core institutions responsible for housing policy act as facilitators of private agents. This contrasts with the dispersion of policy and institutional efforts identified in Panama and El Salvador. Government subsidies are especially directed to households where more of 90 percent of the housing deficit is concentrated. A solution based on public budgets is not sustainable, requiring an active role of the private housing finance sector. Increasing the purchase capacity of families and reducing the cost of financing are necessary conditions to reduce housing deficits.

A fuel tankering model applied to a domestic airline network

SUMMARYThis paper presents a linear programming model designed to determine the optimum fuel loading quantities along a route network for a Brazilian domestic airline. Assuming that there are no volume purchase or storage capacity restrictions on each station, the analysis is carried out for one aircraft on one day of its schedule. Results are extrapolated for a monthly and yearly basis. Through the proposed model, it is seen that such a fuel tankering technique leads to a 5% economical saving, but produces a 1% additional fuel burn. A discussion on the environmental impact for this procedure is also proposed. Copyright © 2011 John Wiley & Sons, Ltd.

On the Structure of a Swing Contract's Optimal Value and Optimal Strategy

Consider a sales contract, called a swing contract, between a seller and a buyer concerning some underlying commodity, with the contract specifying that during some future time interval the buyer will purchase an amount of the commodity between some specified minimum and maximum values. The purchase price and capacity at each time point is also prespecified in the contract. Assuming a random market price process and ignoring the possibility of storage, we look for the maximal expected net gain for the buyer of such a contract, and the strategy that achieves this maximal expected net gain. We study the effects that various contract constraints and market price processes have on the optimal strategy and on the contract value. We show how we can reduce the general swing contract to a multiple exercising of American (Bermudan) style options. Also, in important special cases, we give explicit expressions for the optimal contract value function and the optimal strategy.