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Discusses the relationship between plant availability and maintenance expenditure and their limiting features. Achieving higher plant availability always necessitates a higher maintenance budget and may not be economically feasible in many cases. Through a mathematical modelling the variation of net income with respect to plant availability has been studied and the limiting availability values have been established. Expressions for optimum availability and maintenance cost have also been obtained. An illustrative example has been worked out.

The purpose of this paper is to make a performance model of a shoe upper manufacturing unit of a shoe manufacturing industry by computing both the availabilities, i.e. time dependent system availability (TDSA) and the long‐term availability.

The present work is carried out by developing performance model based on Markov birth‐death process. The unit consists of four subsystems. The first order governing differential equations are derived using the mnemonic rule and further solved by adaptive step‐size control Runge‐Kutta method to calculate the TDSA, while the long‐term availability is calculated using normalizing condition, initial boundary conditions and recursive method. Both the availabilities are considered for system's performance criterion.

The subsystem A, i.e. sewing machine is the most critical from maintenance point of view, which has more impact on the system's performance as compare to other subsystems. The repair priorities of other subsystems have also been proposed.

These methods can also be used to find out the performance of other manufacturing industries.

The results of the present work are very useful for finding the critical subsystem and its effect on the system performance in terms of availability. Further, based on findings the maintenance priorities of various subsystems can be decided.

The purpose of this paper is to propose an availability modeling method of complex multiple units system (CMUS) based on the multi-agent technique.

Based on the multi-agent technique, this paper describes the availability model structure for CMUS and develops agent-based models of components, maintenance policies, maintenance tools, maintenance fields, and maintenance staff, as well as the communication method among the different agents. On the basis of the agent-based availability modeling theory, the availability simulation scheme of CMUS is given using MATLAB. Thus, the availability modeling theory of CMUS and its simulation method are developed. To demonstrate the applicability of the proposed availability modeling method, a numerical example is given.

The proposed agent-based modeling method is applicable to availability modeling of CMUS, including the modeling of component failure, maintenance tools/fields/staff, maintenance policy, and structural/economic dependence among components.

As a bottom-top, modular, expandable, and reusable modeling theory, the agent-based modeling method might be useful for availability modeling of different CMUSs in reality.

The multi-agent technique is introduced into availability modeling of multi-component systems in this paper. Thus, it is possible to model failure of many components, maintenance policies, maintenance tools, maintenance fields, and maintenance staff together for availability analysis of complex systems of equipment.

To define availability importance measures in order to calculate the criticality of each component or subsystem from the availability point of view and also to demonstrate the application of such importance measures for achieving optimal resource allocation to arrive at the best possible availability.

In this study the availability importance measures of a component are defined as a partial derivative of the system availability with respect to the component availability, failure rate, and repair rate. Analyses of these measures for a crushing plant are performed and the results are presented. Furthermore, a methodology aimed at improving the availability of a system using the concept of importance measures is identified and demonstrated by use of a numerical example.

The availability importance measure of a component/subsystem is an index which shows how far an individual component contributes to the overall system availability. The research study indicates that the availability importance measures could be applied in developing a strategy for availability improvement. The subsystem/component with the largest value of importance measure has the greatest effect on the system availability.

The result of availability improvement strategy is demonstrated using only a hypothetical example.

Using availability importance measures will help managers and engineers to identify weaknesses and indicate modifications which will improve the system availability.

This paper presents the concept of availability importance measure for a component/subsystem. It also introduces some availability importance measures based on failure rate, mean time between failures (MTBF), and repair rate/mean time to repair (MTTR) of a component /subsystem. The concept of importance measures is used to prioritise the components or subsystems for the availability improvement process.

Based on the conservation of resource theory, this paper explores the impact of differentiated transformational leadership on employees' taking charge in the context of Chinese organizations, with psychological availability as a mediator and collectivism orientation as a moderator.

The authors distributed paired questionnaires to 67 team managers and 219 team members to obtain research data and established a hierarchical linear model for the hypothesis testing.

The results show that team-focus transformational leadership has a significant positive impact on employees' taking charge, and individual-focus transformational leadership has a significant negative impact on employees' taking charge. Specifically, psychological availability plays a partial mediating role between differentiated transformational leadership and employees' taking charge. Moreover, collectivism orientation has no significant moderating effect between team-focus transformational leadership and psychological availability. But it has a significant moderating effect between individual-focus transformational leadership and psychological availability, i.e. the higher the level of collectivism orientation, the stronger the negative effect of individual-focus transformational leadership on psychological availability.

The paper notes the hierarchy of differentiated transformational leadership and divides it into team-focus transformational leadership and individual-focus transformational leadership. It also provides a new mechanism and boundary condition, i.e. differentiated transformational leadership has an impact on employees' taking charge through psychological availability and collectivism orientation is a moderator.

This paper empirically investigates the relationship between financial availability and crime by measuring it across five dimensions: banking, securities, insurance, private lending and digital inclusive finance.

The study utilizes 2011–2017 data from prefecture-level cities as a representative sample. Moreover, these findings remain robust after addressing endogeneity through the use of the historical distance between cities and the railroad network as an instrumental variable.

The findings demonstrate a significant negative relationship between financial accessibility and crime rates. Heterogeneity exists in the inhibitory effect of different types of financial accessibility on crime, with banking finance exhibiting a stronger inhibitory effect compared to private lending. Areas affected by natural disasters and infectious diseases exhibit a stronger inhibitory effect of financial accessibility on crime rates, particularly in areas with severe shocks of natural disasters and epidemics. This effect is attributed to the low financing threshold and easy access to private lending, which plays a more effective role than bank finance when people face extreme risks.

There should be stricter regulations imposed on private lending markets and the introduction of more rational legislation aimed at guiding a healthy development within these markets; such measures serve as effective and complementary means for individuals from all walks of life to access credit financing.

The regulation of financial resources by the government should always prioritize ensuring the accessibility of financial policies to cater to the needs of the majority population.

This study is for the first time in an emerging economy context, the causal relationship between financial accessibility and crime. To provide a more comprehensive measure of financial accessibility in a region, this paper proposes a five-dimensional methodology.

While steady-state analysis is useful, it does not consider the inherent transient characteristics of repairable systems' behavior, especially in systems that have relatively short life spans, or when their transient behavior is of special concern such as the motivating example used in this paper, military systems. Therefore, a maintenance policy that considers both transient and steady-state availability and aims to achieve the best trade-off between high steady-state availability and rapid stabilization is essential.

This paper studies the transient behavior of system availability under the Kijima Type II virtual age model. While such systems achieve steady-state availability, and it has been proved that deploying preventive maintenance (PM) can significantly improve its steady-state availability, this improvement often comes at the price of longer and increased fluctuating transient behavior, which affects overall system performance. The authors present a methodology that identifies the optimal PM policy that achieves the best trade-off between high steady-state availability and rapid stabilization based on cost-availability analysis.

When the proposed simulation-based optimization and cost analysis methodology is applied to the motivating example, it produces an optimal PM policy that achieves an availability–variability balance between transient and steady-state system behaviors. The optimal PM policy produces a notably lower availability coefficient of variation (by 11.5%), while at the same time suffering a negligible limiting availability loss of only 0.3%. The new optimal PM policy also provides cost savings of about 5% in total maintenance cost. The performed sensitivity analysis shows that the system's optimal maintenance cost is sensitive to the repair time, the shape parameter of the Weibull distribution and the downtime cost, but is robust with respect to changes in the remaining parameters.

Most of the current maintenance models emphasize the steady-state behavior of availability and neglect its transient behavior. For some systems, using steady-state availability as the sole metric for performance is not adequate, especially in systems that have relatively short life spans or when their transient behavior affects the overall performance. However, little work has been done on the transient analysis of such systems. In this paper, the authors aim to fill this gap by emphasizing such systems and applications where transient behavior is of critical importance to efficiently optimize system performance. The authors use military systems as a motivating example.

This empirical study of one of China's biggest take-out platforms during coronavirus disease 2019 (COVID-19) explores the legal rights and protections for gig workers' availability time.

The study uses a quantitative survey and interviews of take-out platform riders, investigating the intrinsic features of working time and availability time. Labour law professionals and scholars are interviewed to verify the findings.

The availability time of take-out platform riders is difficult to define under the current legal working-time framework. There is a need for a specific method to define availability time, considering the multiple factors in gig-take-out-sector work. One option is to apply working-time regulations to availability time but to use a proportionality test to preserve flexibility whilst the platform offers protection to the riders during that time.

Pandemic-related travel restrictions limited the authors' study to one take-out platform in Beijing. Future studies should cover a wider geographical area and multiple take-out platforms.

The study uniquely evaluates the availability time of take-out platform riders to determine appropriate public policy and theoretical implications. It proposes a proportionality test regulating riders' availability. In particular, the workers being “at leisure” during availability time could mitigate the platform's liability for full remuneration or moderate the ceiling of working hours. The occupational health and safety of riders must be fully protected, as they are still “at the platform's disposal” at that time.

In a world where different communication technologies support social connection, managing unavailability is as important as, if not more important than, managing availability. The need to manage unavailability becomes increasingly critical when users employ several communication tools to interact with various ties. A person's availability information disclosure may depend on different social relationships and the technologies used by the person. The study contributes to the literature by drawing on privacy management theory to investigate how users practice availability management and use its deceptive form, which is sometimes called a butler lie, with various ties across different messaging applications (apps) as part of their online privacy. Relevant factors in mediated communication, including facework, common ground, and interpersonal trust, are included in the developed model.

The authors conducted an online survey (n = 475) to explore the relationship between one's contact with different interactants (significant others, family members, close friends, acquaintances, groups of friends, and groups of acquaintances) and one's practice of availability management and use of butler lies with these interactants at different size levels on various messaging apps.

Factors such as facework, privacy related to technology, and privacy related to social relationships affect the practice of availability management and the use of butler lies. Notably, butler lies are used most frequently with acquaintances and groups of acquaintances and least frequently with significant others. Moreover, the practice of availability management and the use of butler lies are negatively moderated by people's conversational grounding and trust.

The study examined the practice of cross-app availability management with diverse social ties on mobile technologies, which is a socio-informatic practice that is widely adopted in the contemporary digital landscape but on which limited scientific and theoretic research has been conducted. No research has directly investigated users' availability management across multiple apps from a relational perspective. Building on the theoretical framework of privacy management, the paper aims to bridge the gap in the relevant literature. The results of this study can serve as a reference for library professionals to develop information literacy programs according to users' availability management needs. The results also provide insights to system designers for developing messaging tools.

The purpose of the paper is to define the best deployment alternatives for a public protection and disaster relief (PPDR) mobile network service – the implementation alternatives being either a dedicated network, a commercial network or a hybrid of the two network types. The selection criteria are based on the social benefits that the PPDR mobile service is expected to bring to society. The critical parameters are population density and service availability, which both directly relate to the socioeconomic benefits achieved by providing broadband (BB) mobile services in various demographic areas.

A causal loop model has been developed to define the socioeconomic benefits of the PPDR network, the parameters being population density, service availability, socioeconomic value of the service and the costs of the network. The network solution alternatives are studied using the Finnish PPDR network as a reference – analysing various areas of the country with differing population densities from remote, rural and more densely populated suburban and urban areas.

Socioeconomic value is a common measure for assessing the value of governmental investments; population density has a strong impact on the optimum deployment alternatives as the socioeconomic value is directly proportional to this variable. The flat nationwide fee of the mobile users means that the users are subsidised in sparsely populated areas – and overcharged in densely populated areas. This is the main reason why the commercial network seems to be most feasible in rural areas, whereas the dedicated network works best in urban areas. Based on the case study, the commercial network is most preferable up to the point when the population density reaches 50-125 persons/km². After that point, the dedicated network becomes more appropriate. Proposals are being made to improve the availability of the commercial networks enabling them to serve as a PPDR network: ensuring priority functionality and a protected power supply; allowing PPDR subscribers the exclusive use of one of the 700 MHz spectrum bands in restricted, critical areas; and extending use of the existing narrowband PPDR network in areas where communication availability is crucial.

On the one hand, the financing of BB PPDR mobile networks is an unresolved issue in many countries. On the other hand, the ability of commercial BB networks to provide better quality of service is improving, making viable the alternative to subscribe for radio service from a commercial operator. Therefore, the feasibility study on how to provide an optimum mobile BB service for PPDR organisations is of real value at this time.