Railway Infrastructure Asset Management Modelling

Railway infrastructure comprises a large collection of diverse and complex systems and structures. Many of them are aging assets and require a significant budget to deliver the maintenance to ensure the required safety and service performance standards. With such a large amount of money spent each year to maintain and renew the network assets, small percentage savings can amount to substantial sums of money. There is therefore a huge incentive to better understand the degradation that assets experience and how these can be effectively managed through the implementation of efficient maintenance strategies. Track and bridges are the most expensive assets to keep in the required condition, and this chapter provides a method to analyse their degradation and build Petri net models to predict the future state of the asset, the number of each maintenance activity which are expected to be undertaken, and their costs experienced by following a particular strategy. Utilising these models enables the quality of the asset management decisions made to be improved and optimised.

Study on the Applicability of the Exterior Condition Assessment to Evaluate The Physical Vulnerability of Check Dams

Check dams are a typical structural approach used in watershed disaster management systems. Currently, approximately 12,000 check dams have been estimated to be constructed on mountain streams in Korea. More than 90% of these have been constructed in the last 20 years. This rapid increase over a short period of time has attracted attention to the necessity of maintenance strategies for check dams. The purpose of this study is to examine the applicability of the exterior condition assessment to evaluate the degree of deterioration in check dams. We classify the typical damage types of check dams and describe its key characteristics. Moreover, we apply a modified version of the condition assessment for large dams to meet the characteristics of check dams.

Maintenance strategy selection: a comprehensive review of current paradigms and solution approaches

PurposeIn today's competitive industries, the selection of best suitable maintenance strategy is dependent on large number of quantitative and qualitative factors, and it becomes an extensively difficult problem for maintenance engineers. Over the years, a diverse range of solution methodologies have been developed for solving this multi-criteria decision-making (MCDM) problem. In this paper, the authors have presented a comprehensive review of latest maintenance strategy paradigms and solution approaches proposed for the selection of an appropriate strategy in various industries. It would provide a systematic mapping of developments in this field and identify some research gaps to explore further studies.Design/methodology/approachA systematic state-of-the-art comprehensive literature review on maintenance strategy paradigms and selection approaches is presented in this study. In this study, 87 research articles published in peer-reviewed journals, since year 2012, are reviewed.FindingsFor the selection of a suitable maintenance strategy, a variety of criteria are considered to better evaluate the alternatives. In this study, contemporary strategies are discussed, and their applications in different industries are also depicted. Moreover, through the analysis of extant literature, critical criteria are selected and classified in six major categories (namely, economic, technical, safety, environmental, feasibility and social) and further sub-categorized in quantitative and qualitative classes. These clusters of criteria can be helpful as an initial set of criteria for survey and then case- or industry-specific criteria can be shortlisted for further alternative evaluation.Practical implicationsFrom the perspective of maintenance managers, maintenance management can be a very difficult task, considering the numerous factors affecting the decision-making process. In order to help in the decision-making process, this study presents the contemporary maintenance strategies in a systematic manner. In a previous study (Kothamasu et al., 2006), these strategies were classified into repair and prevent classes only. With the developments of autonomous maintenance and design out maintenance (DOM), it was fair to include continuous improvement class. It will help managers and practitioners to identify, according to organization policy, appropriate maintenance strategy alternatives for the asset. A benchmark set of state-of-the-art maintenance strategies are laid out with their applications. The industrial case studies discussed in this study summarizes the optimal maintenance strategies for respective industries. Also, most critical criteria are identified from the existing studies for various industries that can help maintenance practitioners in acknowledging the critical factors and making appropriate decisions. Evaluation parameters for the maintenance strategy selection (MSS) generally conflict with each other, and considering the difficulty of quantifying the qualitative measures, it is a challenging task to determine the optimal trade-off. In order to overcome these challenges, popular MCDM approaches, demonstrating effective results across different industries are discussed with their limitations and applications. Decision-makers can refer this study to identify best suitable decision-making technique for the MSS problem in the industry of their choice. Maintenance managers and engineers can refer the case studies illustrated in Tables 1 and 2 to analyse the MSS techniques proposed by previous studies with industry-specific applications.Social implicationsThis study is an attempt to provide a reference point for research scholars interested in the field of maintenance management and/or development of maintenance strategy framework. This study provides a critical state-of-the-art review of efforts made in the field of MSS. The prominent maintenance strategies being implemented in contemporary industries are discussed with respective case studies. Interested researchers and academicians can familiarize themselves with these strategies and their distinct features in this study. In order to guide future studies and provide a reference point for academicians, MSS critical criteria used in extant literature are identified and classified into a comprehensive benchmark framework. Moreover, the industrial case studies are discussed with the most critical criteria of MSS for different industries and which strategy is most suitable for the respective industries based on these criteria. Table 1 presents different MCDM techniques and their hybrid applications for solving MSS problem that can help researchers in identifying research gaps. Future research can be directed at addressing the limitation of MCDM approach employed in existing studies and comparing the differences in results obtained by the proposed approach. Different industrial case studies with considered maintenance strategy alternatives are presented in Table 2, which can help researchers in identifying the industries that have not been studied yet. Moreover, not all of the existing studies are carried out by considering all the presented benchmark strategies, which can be addressed in future studies by interested researchers. More detailed discussion on research gaps is presented in the following section.Originality/valueFrom the analysis of the extant literature, the authors could observe that the decision-making process adopted in numerous studies was limited to the classical maintenance strategies and not inclusive of aggressive maintenance strategy alternatives. To overcome these limitations and help maintenance managers in the decision-making, this study depicts the contemporary maintenance strategies, critical evaluation criteria and MCDM frameworks (employed to solve the MSS problem with industrial case studies) in a structured manner.

Role of maintenance strategies in advanced epithelial ovarian cancer: a systematic review, network meta-analysis and cost-effectiveness analysis protocol

IntroductionDifferent maintenance strategies have shown efficacy in patients with advanced ovarian cancer, but without drawing any conclusion on which strategy is preferred. Therefore, we will conduct a network meta-analysis and cost-effectiveness analysis to investigate maintenance strategies containing chemotherapy, poly (ADP-ribose) polymerase (PARP) inhibitors and anti-angiogenesis therapy for patients with advanced ovarian cancer.Methods and analysisThe search strategy to identify potentially relevant studies will include hand searches in EMBASE, PubMed, Cochrane library and Web of science. The primary outcome is progression-free survival, defined as the date of randomisation to the date of progression or death. The secondary outcome is overall survival (calculated from the time from randomisation to death from any cause), grade 3–4 haematological and non-haematological toxicities, quality-adjusted life years and incremental cost-effectiveness ratios. Two steps of meta-analysis will be carried out, traditional pair-wise meta-analysis and network meta-analysis. Methodological quality, risk of bias and the strength of evidence from randomised controlled trials (RCTs) will be proposed to assess the quality of RCTs. Heterogeneity, publication bias, subgroup analysis and sensitivity analysis will be explored.Ethics and disseminationThe purpose of our study is to perform a comprehensive efficacy, safety and cost-effectiveness analysis of all maintenance strategies in patients with advanced ovarian cancer. The results will be disseminated through international conference reports and peer-reviewed manuscripts. Ethics approval is not required for network meta-analysis and cost-effectiveness analysis.PROSPERO registration numberCRD42021231814.

Why Perpetrators and Innocent Victims are Sometimes Harshly judged? Belief in a Just World and Other Situational Determinants

Although Belief in a Just World (BJW) has positive influences on well-being, the attempts to maintain these beliefs may give rise to awry judgments in contexts of harm. In a scenario-based study, we examined the associations of general belief in a just world (GBJW) with BJW maintenance strategies, including victim blaming, victim derogation, perpetrator demonization, and compensation. We hypothesized that because these harsh judgments about victims and offenders along with compensation are used as defensive mechanisms against threats to BJW, using a specific strategy depends on the availability of each strategy and the level of a person’s GBJW. Thus, we also tested whether GBJW and situational cues for victim’s respectability and perpetrator’s evilness have interaction effects on various strategies to defend BJW. By manipulating the characteristics of the victim (professor vs. car dealer) and offender (with evilness cues vs. without evilness cues) in a crime scenario, the interaction effects on judgments about victims and perpetrators as well as compensation were investigated. The results indicated that while GBJW interacted with victim’s respectability and perpetrator’s evilness to predict demonization and derogation, there was no three-way interaction and two-way interaction effects between victim’s respectability and perpetrator’s evilness on the four BJW-maintenance strategies. Taken together, our findings highlight the nuanced effects of just world beliefs on how people react to and make sense of violent incidents.

Determining the Environmental Potentials of Urban Pavements by Applying the Cradle-to-Cradle LCA Approach for a Road Network of a Midscale German City

This study used a cradle-to-cradle Life Cycle Assessment (LCA) approach to evaluate the environmental potentials of urban pavements. For this purpose, the urban road network of the City of Münster (Germany) was selected as the case study, and comprehensive data for several phases were collected. The entire road network is composed of flexible pavements designed according to specific traffic loads and consists of main roads (MRs), main access roads (MARs), and residential roads (RSDTs). Asphalt materials, pavement structures, and maintenance strategies are predefined for each type of road and are referred to as “traditional” herein. Some pavement structures have two possible maintenance strategies, denoted by “A” and “B”, with distinguished periods of intervention. To evaluate the impact of using recycled materials, we considered alternative pavement structures composed of asphalt materials containing a greater amount of reclaimed asphalt pavement (RAP). The study was carried out considering analysis periods of 20, 50, 80, and 100 years and using two indicators: non-renewable cumulative energy demand (nr-CED) and global warming potential (GWP). The results show that the use of higher amounts of RAP can mitigate negative environmental impacts and that certain structures and maintenance strategies potentially enhance the environmental performance of road pavements. This article suggests initiatives that will facilitate the decision-making process of city administrators to achieve more sustainable road pavement constructions and provides an essential dataset inventory to support future environmental assessment studies, particularly for European cities.

Analysis of the Repair Time of Finishing Works Using a Probabilistic Approach for Efficient Residential Buildings Maintenance Strategies

In general, the long-term maintenance planning of residential buildings is performed based on uniform repair times. However, in fact, various factors, such as the quality and user patterns, affect the performance of residential building components in the Operation and Maintenance (O&M) phase. Hence, various residential building components are repaired at uncertain times, acting as a risk for the residential building maintenance plan. Therefore, an efficient maintenance plan should be established considering maintenance uncertainty. In this regard, this study aims to analyze the uncertainty of repair times for various finishing works in residential buildings based on a probabilistic methodology and outline the implications for the establishment of efficient maintenance strategies in these buildings. Hence, 47,344 repair data for 63 buildings in 12 public residential building complexes completed between 1991 and 2001 in the Republic of Korea were used for analysis. Before the analysis, a repair time matrix was constructed by classifying the finishing works in 25 types and setting service life times to 6–26 years. The repair time distribution for each finishing work was then derived. Results confirmed that basic repair time setting can be performed and various information for reasonable maintenance decision making regarding each finishing work can be provided through a probabilistic approach. The probabilistic approach can be used as a critical decision-making method because there is uncertainty associated with the repair time of each finishing work owing to the performance degradations of various finishing works due to complex causes. Although this study focused on repair time owing to data collection limitations, maintenance strategies with strategic flexibility can be established by developing probabilistic methods that simultaneously consider frequency and cost by securing additional high-quality cost data.