Repair Policy Research Articles

Development of Pavement Deterioration Models Using Markov Chain Process

A common phenomenon in developing countries is that the function of the pavement in the road network will experience structural damage before the completion of life is reached, and the uncertainty of pavement damage is difficult to predict. Planning for maintenance treatment depends on the accuracy of predicting future pavement performance and observing current conditions. This study aims to apply the Markovian probability operational research process to develop a decision support system predicting future pavement conditions. Furthermore, it determines policies and effectiveness in managing and maintaining roads. A standard approach that can be used by observing the history of pavement damage from year to year is to estimate the transition probability as a Markovian-based performance prediction model. The results show that the application of the model is quite optimal, changes in pavement conditions after repair can be easily compared with an increase in good condition, reaching 92.8%. Routinely and consistently handling road deterioration will give favorable results regarding pavement condition value. This will ease in the management of the road network and the accomplishment of the optimal maintenance and repair policies. Doi: 10.28991/CEJ-2024-010-09-012 Full Text: PDF

An Updated Perspective of the Impact of the 1940 Vrancea Earthquake on Design and Construction Practices in Romania

This study presents an updated view of the effects of the 1940 Vrancea earthquake. Recently compiled studies in the literature from the time of the event, as well as other studies, present the opportunity to gain additional and relevant information regarding this large-magnitude event. The effects of this earthquake on various locations in Romania are compared to those observed after the subsequent large Vrancea earthquake of 1977. An assessment of the economic losses caused by the seismic event is also attempted. The seismic vulnerability of some building typologies commonly used before 1940 is assessed by employing the earthquake damage data and the well-known macroseismic method. The impact of this event on the design and construction practices in Romania is evaluated using the collected information as well. Finally, the policy of repair and strengthening of buildings applied after the event is also discussed, and case studies are presented.

Diameter and dissection of the abdominal aorta and the risk of distal aortic reoperation after surgery for type A aortic dissection

BackgroundSurgery for Stanford type A aortic dissection (TAAD) is associated with an increased risk of late aortic reoperations due to degeneration of the dissected aorta. MethodsThe subjects of this analysis were 990 TAAD patients who survived surgery for acute TAAD and had complete data on the diameter and dissection status of all aortic segments. ResultsAfter a mean follow-up of 4.2 ± 3.6 years, 60 patients underwent 85 distal aortic reoperations. Ten-year cumulative incidence of distal aortic reoperation was 9.6%. Multivariable competing risk analysis showed that the maximum preoperative diameter of the abdominal aorta (SHR 1.041, 95%CI 1.008–1.075), abdominal aorta dissection (SHR 2.133, 95%CI 1.156–3.937) and genetic syndromes (SHR 2.840, 95%CI 1.001–8.060) were independent predictors of distal aortic reoperation. Patients with a maximum diameter of the abdominal aorta >30 mm and/or abdominal aortic dissection had a cumulative incidence of 10-year distal aortic reoperation of 12.0% compared to 5.7% in those without these risk factors (adjusted SHR 2.076, 95%CI 1.062–4.060). ConclusionTAAD patients with genetic syndromes, and increased size and dissection of the abdominal aorta have an increased the risk of distal aortic reoperations. A policy of extensive surgical or hybrid primary aortic repair, completion endovascular procedures for aortic remodeling and tight surveillance may be justified in these patients.Trial registration:ClinicalTrials.gov Identifier: NCT04831073.

Coverage modeling of fault-tolerant system under copula and waiting repair policy

Coverage modeling of fault-tolerant system under copula and waiting repair policy

MINIMASI BIAYA PERAWATAN MESIN VIS PULPER PENGUPASAN BIJI KOPI DENGAN MENGGUNAKAN METODE PREVENTIVE MAINTENANCE DI PTPN XII NGRANGKAH PAWON

The development of industrial technology requires companies to be able to use existing resources. The most important thing in the production process is the machine. PTPN XII Ngrangkah Pawon is a limited liability company owned by the Republic of Indonesia and PT Perkebunan Nusantara III (Persero). The use of machines is also used in the PTPN production process. The purpose of this research is to find out whether it is possible to minimize the cost of maintaining the vis pulper machine through preventive maintenance and repair maintenance methods. This type of research is carried out quantitatively by observing and studying the material obtained during the production process for three years (2020-2022). This research was conducted offline for 1 month starting from early July to August. Data analysis was carried out using two methods, namely repair policies and preventive policies. maintenance using repair maintenance with a period of 3 years, namely in the production process by repair calculation in May 2020 the results were Rp. 497,354/week while calculating maintenance cost preventive maintenance results obtained Rp. 708,817/week by scheduling every 4 weeks. For the results of treatment repair calculation maintenance in May 2021 the production process obtained a result of Rp. 6,797,131/week while on preventive maintenance get the calculation results of Rp. 8,508,950/week with scheduling once a week. Finally, in 2022, in May, the calculation results were obtained using repair maintenance Rp. 373,089/week while on preventive maintenance Rp. 524,366/week with a schedule of 4 weeks. Based on the results of the calculations it is explained that minimizing costs using the method of preventive maintenance can be applied, but to get a cheaper fee it is better to use a repair policy maintenance because the estimated results of spending calculations are cheaper compared to using maintenance expenses for preventive maintenance.

Multi-agent deep reinforcement learning based decision support model for resilient community post-hazard recovery

After a city-scale natural hazard, policymakers should plan sound decisions on the repair sequence to ensure the resilient recovery of the community, which consists of interdependent infrastructures. Stochastic scheduling for repairing interdependent infrastructure systems is a difficult control problem with huge decision spaces. This study proposes a novel decision support model to determine the optimal restoration policies for the purpose of maximizing disaster resilience. A simulation environment is first developed, consisting of hazard intensity assessment, components damage evaluation, system recovery simulation, and resilience quantification. The graph theory is utilized to represent the interdependencies among different systems, and the heterogeneous graph neural network is integrated into this framework to extract the topology and interdependency information of the whole community. The optimal repair policies approximated by neural networks are trained by a multi-agent deep reinforcement learning algorithm, considering uncertainties of the restoration process. The superiority and efficiency of the proposed method are demonstrated through a case study of the Tsinghua University campus, where different decision-making objectives are considered. The results show that the recovery trajectories determined by the proposed model have the highest performance compared to conventional methods. Besides, the proposed methodology based on transfer learning can achieve high computational efficiency for new damage scenarios. This model is promising to be a high-performance, robust decision-support tool for post-hazard repairing decisions.

The Role of Independent Repair in a Circular and Regenerative Economy

AbstractThe focus on the transition to a circular economy has contributed to a growing research interest in repair. This paper investigates the role of independent repair, which consists of individuals, organisations, or businesses engaged in the repair of products without formal authorisation of the brand owners of these products. Repair—and independent repair in particular—is critical in achieving a paradigm shift that is anchored in regenerative sustainability. Especially in the electrical and electronics equipment sector, independent repair is challenged by difficult or expensive access to spare parts and repair information. This paper focuses on the independent electronics repair sector in Oslo. We implemented twenty-five semi-structured interviews with repairers working in commercial independent repair shops, focusing on challenges and opportunities in independent repair. They repaired a wide variety of products: mobile phones, desktop computers, laptops, tablets, cameras, printers, e-mobility batteries, remote-controlled cars, drones, and white goods. The thematic analysis of the interviews revealed three main findings. The independent repair sector employs different business models and strategies to tackle the challenges related to accessing affordable and quality spare parts. Secondly, independent repair fills the gap between expensive authorised repair, mostly covered by warranty or insurance, and discarding a broken product. Thirdly, independent repair has contributed to a circular spare part economy, both locally and on a global level. In the discussion, we address how repair can be understood as a regenerative practice, as well as how policy and regulation of repair, both on an EU and national level, supports or undermines independent repair.

Optimal Repair Policies for Infrastructure Systems with Life Cycle Cost Minimization and Annual Cost Leveling

Optimal Repair Policies for Infrastructure Systems with Life Cycle Cost Minimization and Annual Cost Leveling

Seismic damage rates of buildings considering different repair policies

An approach is proposed for assessing the mean number of times the maximum interstory drift (ID) incurs undesirable seismic damage states annually. The formulation is generalized and can be transformed into a classical formulation to evaluate seismic damage rates while considering structural repairs after sustaining any degree of damage. The formulation adopts a repair policy, which is expressed in terms of an ID threshold, that correlates with a certain level of damage. If this threshold is exceeded by a single earthquake or by a cumulative damage process due to an earthquake sequence, the building is repaired or reconstructed. The damage rates of the structural response of reinforced concrete buildings located in the Valley of Mexico were analyzed in a case study. Three repair policies were considered. The damage rates were found to be associated to an adopted repair policy.

Plan commitment: Replanning versus plan repair

While executing its plan in a dynamic environment where multiple agents are operating, an autonomous agent may suffer a failure due to discrepancies between the expected and actual context and thus must replace its obsolete plan. In its endeavour to fix the failure and reach its original goals, the agent may unknowingly disrupt other agents executing their plans in the same environment. We present a property for plan repair called plan commitment to ensure a responsible repair policy among agents that aims to minimise the negative impact on others. We present arguments to support the claim that plan commitment is a valuable property when an agent may have made bookings and commitments to others. We then propose C-TFLAP, an implementation of a plan repair heuristic that allows adapting a failed plan to the new context while committing as much as possible to the original plan. We demonstrate empirically that: (1) our plan repair achieves more committed plans than plan-stability repair when an agent has made bookings and commitments to others, and (2) compared to typical replanning and plan-stability repair, it can reduce the revisions among agents when failures are avoidable and can decrease the time-loss otherwise. In addition, to demonstrate extensibility, we integrate context-aware knowledge extension with committed repairing to increase the agent’s chances of repairing.

Availability Modeling and Analysis Based on Repair Policy for Selector Distribution Unit (SDU) Platform

Availability Modeling and Analysis Based on Repair Policy for Selector Distribution Unit (SDU) Platform

Destructive Isolationism: Tallying the Cost of America’s Trade Policy and Suggestions for Repair and Reform

Destructive Isolationism: Tallying the Cost of America’s Trade Policy and Suggestions for Repair and Reform

Problems of financing reconstruction of buildings and constructions after the war in Ukraine

The need for extensive reconstruction of buildings and structures will become one of the most important social problems after the war. Existing traditional financing mechanisms will not be able to solve it in the near future. Therefore, the issue of financing the reproduction of buildings and structures on the territory of Ukraine needs an immediate solution, taking into account all possibilities and modern trends in the development of the financial and public sectors. In view of the above, the study reveals the main trends in the development of the construction market during the crisis and during the war, and defines the main prospects and directions of development. Among them, the reproduction of buildings and structures after the war is recognized as key. Since the beginning of the military invasion, there has been a great need for major repairs of existing residential buildings. The indicated issue is critical for certain segments of the population and carries a certain social threat. Financing problems cannot be overcome at the expense of construction companies today. The construction market turned out to be quite sensitive to various crises and disasters. Currently, the market has low rates of profitability, which excludes capital investments with a long payback period. Therefore, there is a need to create an adapted financing mechanism for the reproduction of buildings and structures, which will allow balancing time gaps. It will create an opportunity to attract additional financing at the beginning of investments by construction companies of Ukraine. The following recommendations can be made to improve the efficiency of the repair policy: the introduction of population fees for capital repairs, budget financing of targeted programs for housing repair, sponsorship, use of crowdfunding and international and national fundraising platforms, joint investment institutes, credit unions, etc. The proposed approaches will make it possible to reproduce buildings and structures, and eliminate the acute social need of the population.

Evaluation of reliability characteristics of automated teller machine system using Gumbel–Hougaard family copula repair policies

Evaluation of reliability characteristics of automated teller machine system using Gumbel–Hougaard family copula repair policies

Discussion of signature‐based models of preventive maintenance

Discussion of signature‐based models of preventive maintenance

A sustainable supply chain under VMI-CS agreement with withdrawal policies for imperfect items

Supply Chain (SC) coordination, quality requirements, and environmental issues are the main areas of interest within the field of inventory management. Few studies have integrated these concepts into an inventory problem despite its overwhelming necessity. In this direction, this paper deals with a vendor-buyer SC under the Vendor-Managed Inventory with Consignment Stock (VMI-CS) agreement. According to the agreement, the vendor bears the buyer's financial holding cost in return for the storage of products in the buyer's warehouse. Further, each shipment involves a random fraction of repairable items, which need to be withdrawn from the inventory system. Unlike the existing literature, when repair policy is evaluated not to be profitable, these items can either be salvaged or scrapped in the present problem. In other words, this study aims at providing a decision support model to find the optimal withdrawal policy as a joint quality and lot-sizing policy. To fulfill sustainability criteria, carbon emissions are incorporated into the total cost of SC by considering carbon tax and cap-and-trade regulation. The optimum solution is found through an analytical algorithm. Finally, a numerical study is conducted to illustrate the applicability of the models and gain managerial insights. The results show that the performance of VMI-CS for all withdrawal policies is superior to traditional mechanism, but its cost-saving sharing has to improve. In addition, the sensitivity analyzes reveal that the fraction of imperfect items greatly affects the optimal withdrawal policy. Finally, adopting carbon regulations does not seriously affect the optimal withdrawal policy and inventory decisions but causes a relatively much increase in the total cost.

Learning to compute the metric dimension of graphs

For distinct vertices x,y,z in graph G=(V,E), we say the pair of vertices x,y can be distinguished by vertex z, if the distance inequation dG(x,z)≠dG(y,z) is true. If any two different vertices in graph G can be distinguished by at least one vertex in the vertex subset S⊂V then we say S⊂V is a resolving set of graph G. The one with minimum number of nodes among all of the resolving sets is called a metric base of graph G, of which the cardinality is called the metric dimension of graph G. The metric dimension problem(MDP) of computing the metric dimension of graphs is a kind of complex combinatorial optimization problem. In this paper, a hybrid algorithm for solving the MDP is developed, through which the metric base of graphs can be learned, and consequently the metric dimension of graphs is estimated. It is particular that the hybrid algorithm combines graph representation learning with greedy repair policy. Extensive experiments show that the hybrid algorithm has higher computational accuracy and efficiency on random graphs. It is also further suggested that the learning process of MDP is greatly influenced by the attributes of complex networks and the designs of graph neural networks themselves.

Optimal Repair Policies for Systems Deteriorating After Disruptions

We consider a scenario where a system experiences a disruption, and the states (representing health values) of its components continue to reduce over time, unless they are acted upon by a controller. Given this dynamical setting, we consider the problem of finding an optimal control (or switching) sequence to maximize the sum of the weights of the components, whose states are brought back to the maximum value. We first provide several characteristics of the optimal policy for the general (fully heterogeneous) version of this problem. We then show that under certain conditions on the rates of repair and deterioration, we can explicitly characterize the optimal control policy as a function of the states. When the deterioration rate (when not being repaired) is larger than or equal to the repair rate, and the deterioration and repair rates as well as the weights are homogeneous across all the components, we show that the policy that targets the component with the largest state value at each time step is optimal under certain conditions. On the other hand, if the repair rates are sufficiently larger than the deterioration rates, the optimal control policy is to target the component whose state minus the deterioration rate is least in a particular subset of components at each time step.

Long-term Outcomes of Transatrial-Transpulmonary Repair of Tetralogy of Fallot With Anomalous Coronary Arteries

Repair of tetralogy of Fallot (TOF) can be complicated by the presence of an anomalous coronary artery (ACA) crossing the right ventricular outflow tract (RVOT). This study sought to evaluate the late outcomes of a policy of transatrial-transpulmonary repair for this condition. The transatrial-transpulmonary approach was used in 864 consecutive TOF repairs between 1993 and 2018 at a single institution, of which 55 (6%) patients had an ACA. Nineteen (35%,19/55) patients underwent prior palliation. Late survival and freedom from reoperations were compared with the general cohort of 809 patients who underwent complete repair during the same period. Early mortality was 2% (1/55). Median follow-up was 15.6 years. Late mortality was 6% (3/54). Absence of a preoperative diagnosis of ACA was not a risk factor for worse outcomes in terms of late re-interventions, acute coronary syndrome, residual RVOT gradient, and late mortality. Survival was 91% (95% confidence interval [CI]: 77-96%) at 20 years and was comparable to the general TOF cohort (95%, 95% CI: 90-98%, P = 0.12). Actuarial freedom from any re-intervention was 46% (95% CI: 27-62%) at 20 years, which was also comparable to the general cohort (31%, 95% CI: 20-42%, P = 0.19). The presence of an ACA does not appear to affect late survival or re-intervention rates in patients undergoing transatrial-transpulmonary repair of TOF.

Reliability assessment of multi-computer system consisting n clients and the k-out-of-n: G operation scheme with copula repair policy

Reliability assessment of multi-computer system consisting n clients and the k-out-of-n: G operation scheme with copula repair policy