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Reducing wear of undercarriage track propulsion systems used in heavy construction equipment decreases the maintenance costs and increases the equipment's life. Therefore, understanding key factors that affect the wear rate is critical. This study is an attempt to predict undercarriage wear.

This research analyzes a sample of track-type dozers in the eastern half of North Carolina (NC), USA. Sand percentage in the soil, precipitation level, temperature, machine model, machine weight, elevation above sea level and work type code are considered as factors influencing the wear rate. Data are comprised of 353 machines. Machine model and work code data are categorical. Sand percentage, elevation, machine weight, average temperature and average precipitation are continuous. ANOVA is used to test the hypothesis.

The study found that only sand percentage has a significant impact on the wear rate. Consequently, a regression model is developed.

The regression model can be used to predict undercarriage wear and bushing life in soils with different sand percentages. This is demonstrated using a hypothetical scenario for a construction company.

This work is useful in managing maintenance intervals of undercarriage tracks and in bidding construction jobs while predicting machine operating expense for each specific job site soil makeup.

The purpose of this paper is to design a modified version of the double sampling plan to handle the inspection processes requiring a minimum sample size to assure the median life for the products under the new Weibull–Pareto distribution. The economic design of the proposed plan is also considered to assure the product's lifetime with minimum cost.

The authors have developed an optimization model for obtaining the required plan parameters by solving simultaneously two non-linear inequalities and such inequalities have been formed based on the two points on the operating characteristic curve approach.

The results show that the average sample number, average total inspection and total inspection cost under the proposed plan are smaller than the same of a single sampling plan. This means that the proposed plan will be more efficient than a single sampling plan in reducing inspection effort and cost while providing the desired protection.

The proposed modified double sampling plan designed to assure the median life of the products under the new Weibull–Pareto distribution is not available in the literature. The proposed plan will be very useful in assuring the product median lifetime with minimum sample size as well as minimum cost in all the manufacturing industries.

The incidents of hotel theft constitute a significant cause of concern for the hotel industry. Such incidents result in substantial financial implications, inventory management issues and complications in finding exact replacements. This study, therefore, investigates customer stealing practices in Indian hotel industry.

A structured email interview was conducted with twenty-five senior hotel managers. The data were analyzed by adopting a coding technique using inductive content analysis.

The results were discussed under seven headings-extent of such stealing incidents, financial consequences of such practices, strategies to prevent such instances and, finally, how to deal with customers when caught stealing.

This study highlighted themes related to the profile of customers involved in stealing practices, motives, consequences and strategies required to manage such customers. Future studies can focus on restaurants, airlines, airports and tourist attractions to identify strategies and best practices for preventing such practices.

The study's findings have tremendous potential for the hospitality industry. Dealing with customers’ stealing practices is a very sensitive issue. Furthermore, hotels bear lots of expenses if the policy for tackling the problem still needs to be implemented. Furthermore, if not handled professionally, a lack of effective guidelines can cause embarrassment for managers.

The study has the potential to raise awareness among the members of society to be more responsible toward hotel property.

This study extends to the limited literature on hotel guests' theft. The comprehensive analysis of the themes generated from an interview with the senior managers of the hotel industry provides a unique insight into the nature of the problem. The solutions offered in this study are an original contribution to the literature.

This paper aims to propose a new method to derive custom dynamic cyber risk metrics based on the well-known Goal, Question, Metric (GQM) approach. A framework that complements it and makes it much easier to use has been proposed too. Both, the method and the framework, have been validated within two challenging application domains: continuous risk assessment within a smart farm and risk-based adaptive security to reconfigure a Web application firewall.

The authors have identified a problem and provided motivation. They have developed their theory and engineered a new method and a framework to complement it. They have demonstrated the proposed method and framework work, validating them in two real use cases.

The GQM method, often applied within the software quality field, is a good basis for proposing a method to define new tailored cyber risk metrics that meet the requirements of current application domains. A comprehensive framework that formalises possible goals and questions translated to potential measurements can greatly facilitate the use of this method.

The proposed method enables the application of the GQM approach to cyber risk measurement. The proposed framework allows new cyber risk metrics to be inferred by choosing between suggested goals and questions and measuring the relevant elements of probability and impact. The authors’ approach demonstrates to be generic and flexible enough to allow very different organisations with heterogeneous requirements to derive tailored metrics useful for their particular risk management processes.

This study aims to investigate key aspects of public ownership of land, expropriation and compensation laws and practices in Ethiopia with special reference to Burayu Town.

A mixed research technique of descriptive and analytic approach is applied in the research. This study used a purposive sampling technique to select case study counties and a systematic method for sampling households. Questionnaire surveys, focus group discussions, interviews and observations were used to collect empirical data. Average, percentage and paired-sample t-test analyses are used for quantitative data analysis.

Significant discrepancies exist between the expropriation laws and how property valuation and compensation are practiced in Ethiopia. The findings include the arbitrariness in designating public interest status to projects; unfair property valuation practice that neglects location factor to determine market value due to a skewed understanding of public ownership of land; and the assignment of property valuators who have no valuation expertise and proper knowledge of expropriation related laws. Findings revealed the socio-economic status of expropriated households has deteriorated due to the expropriation of their landholding.

It was difficult to locate the relocated persons as they were resettled in different localities. Furthermore, the town officers were not forthcoming to provide complete information on the expropriation and compensation procedures they followed. However, this study overcame the limitations through persistent requests and availing time for the data gathering.

The findings indicated the need to redefine relationships between public ownership of land, public interest and expropriation of landholding. A proper understanding of the triad will pave the way for better expropriation practice in Ethiopia and in countries where land is under public ownership.

The social implication of the study revealed that the socio-economic situation of relocated persons was adversely affected due to the poor implementation of laws.

The disparity between public ownership of land and the rights of citizens on landholding is misunderstood by policymakers. Research has shown for the first time the root cause for the discontent of expropriated persons in Ethiopia.

This paper aims to assess a measurement model of green cleaning for green buildings in Malaysia. Being one of the contributors to the indoor environmental quality performance, green cleaning has become one of the significant aspects that need to be considered for the well-being and performance of a building, particularly in a green building's operations and maintenance performance. Green buildings without green cleaning practices would hinder the benefits that should be rendered economically, socially and environmentally. However, the absence of clear green cleaning components and requirements in Malaysia has become a motivation to undertake this research.

A questionnaire survey involving cleaning service providers and green building index (GBI) facilitators was carried out, and the data was then analyzed using partial least squares structural equation modeling. However, this paper will only be focusing on the measurement model assessment.

Most of the green cleaning components and requirements are acceptable in the model except integrated pest management (in the cleaning procedure component) and hand soaps (in the product and materials component) due to lower factor loadings. Therefore, these two requirements were removed from the measurement model.

Due to a paucity of professionals in the field of green cleaning, the researchers have selected GBI facilitators and cleaning service providers as respondents for this research. The researchers assumed that GBI facilitators are aware of acceptable products and materials for green buildings; meanwhile, cleaning service providers know what is the best cleaning technique and process that helps in achieving cost and resource efficiency. This research also assumed that the green cleaning components identified can be applied to any type of green building, regardless of the differences in needs in each type of building.

This discovery will give the industry, particularly cleaning service providers and green building management teams, a first look at the green cleaning components and requirements.

This paper fulfills the need to study how green cleaning helps in achieving the benefits rendered by green buildings.

The study aims to design the limited number of random working cycle as a warranty term and propose two types of warranties, which can help manufacturers to ensure the product reliability during the warranty period. By extending the proposed warranty to the consumer's post-warranty maintenance model, besides the authors investigate two kinds of random maintenance policies to sustain the post-warranty reliability, i.e. random replacement first and random replacement last. By integrating depreciation expense depending on working time, the cost rate is constructed for each random maintenance policy and some special cases are provided by discussing parameters in cost rates. Finally, sensitivities on both the proposed warranty and random maintenance policies are analyzed in numerical experiments.

The working cycle of products can be monitored by advanced sensors and measuring technologies. By monitoring the working cycle, manufacturers can design warranty policies to ensure product reliability performance and consumers can model the post-warranty maintenance to sustain the post-warranty reliability. In this article, the authors design a limited number of random working cycles as a warranty term and propose two types of warranties, which can help manufacturers to ensure the product reliability performance during the warranty period. By extending a proposed warranty to the consumer's post-warranty maintenance model, the authors investigate two kinds of random replacement policies to sustain the post-warranty reliability, i.e. random replacement first and random replacement last. By integrating a depreciation expense depending on working time, the cost rate is constructed for each random replacement and some special cases are provided by discussing parameters in the cost rate. Finally, sensitivities to both the proposed warranties and random replacements are analyzed in numerical experiments.

It is shown that the manufacturer can control the warranty cost by limiting number of random working cycle. For the consumer, when the number of random working cycle is designed as a greater warranty limit, the cost rate can be reduced while the post-warranty period can't be lengthened.

The contribution of this article can be highlighted in two key aspects: (1) the authors investigate early warranties to ensure reliability performance of the product which executes successively projects at random working cycles; (2) by integrating random working cycles into the post-warranty period, the authors is the first to investigate random maintenance policy to sustain the post-warranty reliability from the consumer's perspective, which seldom appears in the existing literature.

This paper proposes optimisation models to evaluate and examine the selling of extended warranty policies in terms of improved profits in producing/marketing remanufactured products. These models are numerically solved using a quadratic programming solution approach and implemented in the decision support system (DSS).

The purpose of this paper is to develop the optimisation models for a DSS and evaluate different warranty policies for buyers.

This study has demonstrated the flexibility and usefulness of a model-driven DSS for the quality and warranty management, which is applied to examine and evaluate different configurations (i.e. component reuse, rebuild and recycle) for remanufactured products and propose the selling of extended warranty policies for buyers.

The developed model-driven DSS can assist manufacturers to select and increase the number of components, e.g. to be reused, rebuilt, and recycled for producing a remanufactured product and propose suitable warranty policies for buyers. However, this study focusses only on the evaluation of warranty policies for specific remanufactured products in a DSS, i.e. types of air compressors for production operations in manufacturing industry.

This study developed optimisation models to be used in a DSS for proposing the selling of extended warranty of a remanufactured product to improve customer satisfaction and maximise the gained profits for manufacturers.

Poor indoor air quality (IAQ) contributing to occupants’ health symptoms is a universal, typically ventilation-related, problem in schools. In cold climates, low-cost strategies to improve IAQ in a naturally ventilated school are rare since conventional methods, such as window opening, are often inappropriate. This paper aims to present an investigation of strategies to relieve health symptoms among school occupants in naturally ventilated school in Finland.

A case study approach is adopted to thoroughly investigate the process of generating the alternatives of ventilation redesign in a naturally ventilated school where there have been complaints of health symptoms. First, the potential sources of the occupants’ symptoms are identified. Then, the strategies aiming to reduce the symptoms are compared and evaluated.

In a naturally ventilated school, health symptoms that are significantly caused by insufficient ventilation can be potentially reduced by implementing a supply and exhaust ventilation system. Alternatively, it is possible to retain the natural ventilation with reduced number of occupants. The selected strategy would depend considerably on the desired number of users, the budget and the possibilities to combine the redesign of ventilation with other refurbishment actions. Furthermore, the risk of poorer indoor air caused by the refurbishment actions must also be addressed and considered.

This study may assist municipal authorities and school directors in decisions concerning improvement of classroom IAQ and elimination of building-related symptoms. This research provides economic aspects of alternative strategies and points out the risks related to major refurbishment actions.

Since this study presents a set of features related to indoor air that contribute to occupants’ health as well as matters to be considered when aiming to decrease occupants’ symptoms, it may be of assistance to municipal authorities and practitioners in providing a healthier indoor environment for pupils and teachers.

The airlines cancel their flights frequently because of factors that they do not have any control over. Spare aircraft can potentially address some of the issues caused by cancelled flights. This paper aims to offer an exploratory study into the financial and operational viabilities of spare aircraft for airlines.

Mathematical models are proposed to evaluate the financial and operational metrics under different scenarios. The models are applied to Delta, Spirit and Southwest Airlines with different business models. All data are extracted from US Bureau of Transport Statistics, Cirium Diio Mi and CAPA databases. The IBM Cplex solver was used to execute the binary linear program models.

The research revealed that factors such as airline network size, hub and spoke structure and average weekly flight cancellations are crucial in establishing the need for spare aircraft. For the number of weekly cancellations, there exist break-even values that reasonably justify spare aircraft.

Models can be customized and applied to other modes of transportations.

This study is the first to consider the use of spare aircraft in airlines from both financial and operational perspectives within the scope of the mathematical model. The analyses identify financial break-even points for a number of spare aircraft and their home base locations for three airlines. Operational utilization of spare aircraft is studied and contrasted with financial metrics.