The relation between technical debt and corrective maintenance in PHP web applications

In this chapter maintenance concept is defined and maintenance types are classified with regard to implementing maintenance policies toward preventive maintenance. Especially achieving planned maintenance policies toward preventive (planned) maintenance and condition based maintenance policies toward predictive maintenance is taken into consideration primarily. Maintenance concept is defined and maintenance types are classified. Due care is given for ‘Preventive Maintenance’ in this chapter. In general ‘Maintenance’ term could be defined as; The integration of all possible technical and administrative actions, including planning, supervising, monitoring and controlling toward retaining an item, a system, a machine to restore their original functional state in which they can perform the intended functions. In addition maintenance, include protective and corrective actions to keep the plant operational system in intended conditions or to maintain the acceptable manufacturing conditions. Optimum maintenance policies aims to sustain system reliability and robustness within minimum cost. In line with the progress of industry, increase in the system, material and manpower costs, increasing demand for robustness and the complex structure of the machines increases also the importance of maintenance policies. Maintenance types could be divided into two main parts namely; 1. Preventive Maintenance, 2. Corrective Maintenance. Preventive Maintenance is also classified into following sub groups; 1.a- Planned Maintenance, 1.b- Predictive Maintenance, 1.c- Advanced Maintenance Implementations; 1.c.1 Reliability Centered Maintenance 1.c.2 Risk Based Maintenance. All of these maintenance types elaborated with relevant figures in the chapter. In this chapter Comparison of Planned and Unplanned (corrective) Maintenance (With regard to transaction and output) is defined with a table. Additionally, Comparison of Planned and Unplanned (corrective) Maintenance (With regard to infra structure) is also tabulated. ‘Benefits of Preventive & Predictive Maintenance’ and ‘Predictive Maintenance Methods’ are defined with relevant descriptive figures in the chapter. For Corrective Maintenance, basic definitions and corrective maintenance steps, types of corrective Maintenance, improvement strategies in corrective maintenance effectiveness are also given. In the final part of ‘Results and conclusions’ expected and verified benefits of implementing maintenance policies for planned and predictive maintenance are explained. Comparisons in some maintenance policies is given.

The impact of Technical Debt (TD) on software maintenance and evolution is of great concern, but recent evidence shows that a considerable amount of TD is fixed by the same developers who introduced it; this is termed self-fixed TD. This characteristic of TD management can potentially impact team dynamics and practices in managing TD. However, the initial evidence is based on low-level source code analysis; this casts some doubt whether practitioners repay their own debt intentionally and under what circumstances. To address this gap, we conducted an online survey on 17 well-known Java and Python open-source software communities to investigate practitioners' intent and rationale for self-fixing technical debt. We also investigate the relationship between human-related factors (e.g., experience) and self-fixing. The results, derived from the responses of 181 participants, show that a majority addresses their own debt consciously and often. Moreover, those with a higher level of involvement (e.g., more experience in the project and number of contributions) tend to be more concerned about self-fixing TD. We also learned that the sense of responsibility is a common self-fixing driver and that decisions to fix TD are not superficial but consider balancing costs and benefits, among other factors. The findings in this paper can lead to improving TD prevention and management strategies.

The maintenance of any system can be categorized in two ways: failure based maintenance (corrective maintenance) and life based maintenance (preventive maintenance). The time interval at which the preventive maintenance could be scheduled is dependent on both the life distribution of the subsystems/components and the total cost involved in the maintenance activity. However, the corrective maintenance cannot be avoided when a random failure of a component occurs. The total cost of the maintenance depends on the number of components replaced during the entire operating period of the system and the respective cost involved in maintenance actions. In this paper the preventive maintenance schedule (t/sub 0/) is calculated taking the failure distribution of a component as Weibull. The variation in (t/sub 0/) with respect to the shape parameter (/spl beta/) and characteristic life (/spl alpha/) of the Weibull distribution was studied by the author for a given preventive maintenance cost and corrective maintenance cost. The ratio of the corrective maintenance cost to the preventive maintenance cost (R/sub cp/) has a significant effect on the maintenance schedule (t/sub 0/). Thus the variation of (t/sub 0/) with (R/sub cp/) is addressed in this paper. The ratio is varied between 10 and 1.5. It is found that the (t/sub 0/) value increases as shape parameter increases when the ratio is 10 whereas the (to) value decreases when the ratio is 1.5. This shows that as we decrease the cost ratio (R/sub cp/) the frequency of preventive maintenance decreases with shape parameter. This in turn implies that the frequency of the preventive maintenance schedule can be kept at minimum by bringing down the cost of corrective maintenance. Sensitivity analysis carried out on the (t/sub 0/) values indicates that the variation in the cost of maintenance is about 5 to 8 percent :in all the cases even when the value of (t/sub 0/) is increased. by 50% over the optimum value. This indicates, while the optimum value of (to) obtained may be of academic interest, one can 'in practice' choose a convenient value near the optimum without appreciably affecting the advantage in terms of cost.

Basically, scheduling concept for mixture policy of preventive with corrective maintenance is scheduled under the least assigned workers whose have high utilization of their maintenance responsibilities. Whereas, scheduling algorithm will be exploited and applied for determining the cyclic shift work and workers scheduling in according to entirely response to the activities of preventive and corrective maintenance. Additionally, every worker will have similar of the amount day-work and day-off with the equivalency vacancies on their weekend. The thinking on the basis of probabilistic failure rate concept is the main objective of this research study, whilst the algorithm is thought on basis of mixture policy of preventive and corrective which is to be useful for all industries to do their maintenance actions.

The purpose of this study is to establish and maintain a program for monitoring quality indicators (QIs) for the improvement of the Biomedical Equipment Maintenance Management program at Christian Medical College (CMC) Vellore. Fault index (FI) indicators were applied to planned preventive maintenance (PPM)/corrective maintenance (CM) data. The findings were turned into meaningful reports to gain quantitative and qualitative insight into the maintenance program and equipment performance. This study was carried out in the Biomedical Engineering department of CMC Vellore, along with the Quality Management Cell in April 2020. This study was conducted on 2019 data on an experimental basis to find out the applicability and usefulness of selected QIs. Data were collected from the computerized maintenance management software (CMMS) called BMESOFT which was developed in-house in CMC Vellore. Reports were generated by applying the QIs. These reports were analyzed, and findings were used for improving the quality of maintenance activities. The FI indicator and analysis of critical biomedical equipment helped us to identify the repetitive faults and affected equipment. It was found that FI was high for ventilators and infusion pumps. The trend was repetitive in all quarters. This study helped us to identify the affected equipment, affected model, and affected location, and the ratio of PPM revealed that the annual average rate of completion of PPM work orders was 92.46% with respect to a set target of 90%. The Ratio of CM revealed that the annual average rate of completion of CM work orders was 90.86% with respect to a set target of 90%. To achieve a target of 95% completion, the maintenance activities need to be reviewed, and measures should be taken to improve the completion ratio. The factors affecting these ratios have been listed out and the corrective measures were planned to improve the same. This study is an attempt to apply FI as the QI to biomedical equipment maintenance data and confirm its applicability in improving the biomedical equipment management program. The experimental analysis of these QIs on 2019 data clearly showed that FI QIs are very effective in evaluating the performance of biomedical equipment management program and also find the root cause of repetitive faults.

Chapter 2 - Measuring and Monitoring Technical Debt

Making sub-optimal design decisions during software development leads to the accumulation of Technical Debt (TD) in software projects. There are tools to identify TD Items in software code through static code analysis. However, quantifying TD to support decision-making on whether to keep taking on TD or if it is time to refactor TD is a difficult task, and proposed approaches for this still lack consensus. Prior work observed that TD Interest could be further decomposed into constituents 'New Code Cost' and 'Rework Cost', which gives an interesting direction of research to explore TD quantification in terms of these costs. Therefore, through our empirical study, we plan to explore the relationship between TD, New Code Cost and Rework Cost in Open-Source Software Projects. This paper reports on an initial motivating study, our plan for future work and implications for researchers.

The work presented in this paper addresses the problem of joint optimization of the production, setup and corrective maintenance activities of a manufacturing system. This system consists of a machine subject to breakdowns and repairs and producing two types of parts. A corrective maintenance strategy whose repair rate depends on the number of setup operations already performed on the production system is considered in this work. The objective of this research is to propose a policy that controls production, setup, and corrective maintenance. The contribution of this paper is through the control of the repair rate, combined with the planning of production and setup in a dynamic and stochastic context. Optimality conditions in the form of Hamilton-Jacoby-Bellman (HJB) equations are obtained and a numerical approach is proposed in order to deal with the joint optimization issues. Extensive simulations are performed to address many scenarios that illustrate the interactions between production, setup and maintenance activities.

Equipment maintenance and system reliability are important factors affecting the organisation’s ability to provide quality and timely services to customer. While maintenance remains an important function to manufacturing, it is only recently that attempts have been made to quantify its impact on equipment performance. In this research, an approach of linking maintenance with equipment performance is developed using simulation modelling. The modelling approach involves defining probabilistic models and assumptions affecting system performance, such as: the probabilistic model for the initial failure rate/intensity of the equipment; the probabilistic model for the system deterioration and corresponding effect; the probabilistic model for the random times of corrective maintenance (CM) and preventive maintenance (PM) that takes into the account the types of maintenance plans/policies and the potential dependency between CM and PM times; and the probabilistic model for the random effects of CM and PM on the reliability of the equipment. Using a continuous manufacturing equipment, the model is used to analyse the impact of deterioration, failures and maintenance (policies, timing and efficiency) on equipment performance. It is shown that modelling the effect maintenance provides a basis of evaluating maintenance efforts with the potential application in performance evaluation and decision support while investigating opportunities for manufacturing equipment performance improvement.

One major problem in using static analyzers to manage, monitor, control, and reason about technical debt is that industrial projects have a huge amount of technical debt which reflects hundreds of quality rule violations (e.g., high complex module or low comment density). Moreover the negative impact of violating quality rules (i.e., technical debt interest) may vary across rules or even across contexts. Thus, without a context-specific validation and prioritization of quality rules, developers cannot effectively manage technical debt. This paper reports on a case study aimed at exploring the interest associated with violating quality rules; i.e., we investigate if and which quality rules are important for software developers. Our empirical method consists of a survey and a quantitative analysis of the historical data of a CMMI Level 5 software company. The main result of the quantitative analysis is that classes violating several quality rules are five times more defect prone than classes not violating any rule. The main result of the survey is that some rules are perceived by developers as more important than others; however, there is no false positive (i.e., incorrect rule or null interest). These results pave the way to a better practical use of quality rules to manage technical debt and describe new research directions for building a scientific foundation to the technical debt metaphor.

Nowadays, almost every firm focuses to beat the global competition across the worldwide. In order to deal with such situation, companies are undertaking efforts to improve the productivity of their products but at the minimum possible cost. Asset management is one of the ways to enhance the productivity under cost constraint which may also be seen as the management strategy for different the phases of asset life cycle. Operations and maintenance is one of the important phases of asset life cycle that can be focussed to improve the productivity. This phase may extend the equipment life, improves availability and retains them in healthy positions. But at the same time, frequent maintenance actions may increase the maintenance cost thereby increase the life cycle cost of a product. The maintenance cost only includes the preventive and corrective maintenance cost and which may in-turn depend upon the scheduled maintenance interval. Thus, a trade-off between maintenance actions and operational objectives (i.e. availability, etc.) is required to minimize the maintenance cost. In this paper, the genetic algorithm is applied to optimize the maintenance cost for higher performance (i.e. availability). A case study is taken into consideration for implementing the GA to optimize the objective function. The three different cases are presented, in the first case, subassemblies are repaired during maintenance action(s); in the second case subassemblies are repaired in preventive maintenance action and while replaced in corrective maintenance action; in the last case, the subassemblies are replaced in both kind of maintenance. In order to check the robustness of the solution, the sensitivity analysis is also performs and that validates the strength of the solution methodology.

Optimal maintenance policy for a system subject to damage in a discrete time process

Background: The COVID-19 outbreak interrupted regular activities for over a year in many countries and resulted in a radical change in ways of working for software development companies, i.e., most software development companies switched to a forced Working-From-Home (WFH) mode. Aim: Although several studies have analysed different aspects of forced WFH mode, it is unknown whether and to what extent WFH impacted the accumulation of technical debt (TD) when developers have different ways to coordinate and communicate with peers. Method: Using the year 2019 as a baseline, we carried out an industrial case study to analyse the evolution of TD in five components that are part of a large project while WFH. As part of the data collection, we carried out a focus group with developers to explain the different patterns observed from the quantitative data analysis. Results: TD accumulated at a slower pace during WFH as compared with the working-from-office period in four components out of five. These differences were found to be statistically significant. Through a focus group, we have identified different factors that might explain the changes in TD accumulation. One of these factors is responsibility diffusion which seems to explain why TD grows faster during the WFH period in one of the components. Conclusion: The results suggest that when the ways of working change, the change between working from office and working from home does not result in an increased accumulation of TD.

Context: Software startups are software-intensive early phase companies with high growth rates. Previous researchers regarded startups’ time to market as short and decisive in establishing the product/service success. This led to shortcuts in software engineering decisions. Researchers in previous investigations documented a high accumulation of technical debt (TD) in early startup phases. However, we found little evidence in the literature concerning TD when startups transition to the growth phase. Aim: Our goal was to evaluate how the transition from early to growth phases affects TD perception in software startups. Methodology: We conducted a pilot study guided by semi-structured interviews from multiple software startup cases. Results: We identified the four following dimensions: (1) managing, (2) accepting, (3) avoiding, and (4) ignoring TD. Contribution: Our study will allow practitioners to address TD in growth-phase software startups. Future researchers can benefit from our findings by conducting exploratory studies and providing educated recommendations.

JavaScript (JS) is one of the most popular programming languages for developing client-side applications mainly due to allowing the adoption of different programming styles, not having strict syntax rules, and supporting a plethora of frameworks. The flexibility that the language provides may accelerate the development of application, but also pose threats to the quality of the final software product, e.g., introducing Technical Debt (TD). TD reflects the additional cost of software maintenance activities to implement new features, occurring due to poorly developed solutions. Being able to forecast the levels of TD in the future can be extremely valuable in managing TD, since it can contribute to informed decision making when designating future repayments and refactoring budget among a company's projects. Despite the popularity of JS and the undoubtful benefits of accurate TD forecasting, in the literature, there is available only a limited number of tools and methodologies that are able to: (a) forecast TD during software evolution, (b) provide a ground-truth TD quantifications to train forecasting, since TD tools that are available are based on different rulesets and none is recognized as a state-of-the-art solution, (c) take into consideration the language-specific characteristics of JS. As a main contribution for this study, we propose a methodology (along with a supporting tool) that supports the aforementioned goals based on the Backward Stepwise Regression and Auto-Regressive Integrated Moving Average (ARIMA). We evaluate the proposed approach through a case study on 19,636 releases of 105 open-source applications. The results point out that: (a) the proposed model can lead to an accurate prediction of TD, and (b) the Number of appearances of the “new” and “eval” keyword along with the number of “anonymous” and “arrow” functions are among the features of JavaScript language that are related to high levels of TD.