Priority Repair Research Articles

Reliability and sensitivity analysis of a maintainable energy system under priority repair

Reliability and sensitivity analysis of a maintainable energy system under priority repair

Corrosion Damage Detection in Headrace Tunnel Using YOLOv7 with Continuous Wall Images

Infrastructure that was constructed during the high economic growth period of Japan is starting to deteriorate; thus, there is a need for the maintenance and management of these structures. The basis of maintenance and management is the inspection process, which involves finding and recording damage. However, in headrace tunnels, the water supply is interrupted during inspection; thus, it is desirable to comprehensively photograph and record the tunnel wall and detect damage using the captured images to significantly reduce the water supply interruption time. Given this background, the aim of this study is to establish an investigation and assessment system for deformation points in the inner walls of headrace tunnels and to perform efficient maintenance and management of the tunnels. First, we develop a mobile headrace photography device that photographs the walls of the headrace tunnel with a charge-coupled device line camera. Next, we develop a method using YOLOv7 for detecting chalk marks at the damage locations made during cleaning of the tunnel walls that were photographed by the imaging system, and these results are used as a basis to develop a system that automatically accumulates and plots damage locations and distributions. For chalking detection using continuous wall surface images, a high accuracy of 99.02% is achieved. Furthermore, the system can evaluate the total number and distribution of deteriorated areas, which can be used to identify the causes of change over time and the occurrence of deterioration phenomena. The developed system can significantly reduce the duration and cost of inspections and surveys, and the results can be used to select priority repair areas and to predict deterioration through data accumulation, contributing to appropriate management of headrace tunnels.

Dynamic Analysis of the Multi-state Reliability System with Priority Repair Discipline

Dynamic Analysis of the Multi-state Reliability System with Priority Repair Discipline

FEATURES OF THE ARCHITECTURAL AND SPATIAL ARRANGEMENT OF TARAKANIV FORT

The study of Tarakaniv Fort, the largest defensive fort in Ukraine, which has survived to this day with partial losses of material substance as a result of military operations, which is decaying under the influence of atmospheric factors, is extremely relevant in our time, when the country is in a state of war. The purpose of the article is to analyze the planning and architectural-spatial structure of the Tarakan Fort, to reveal its architectural-constructive features, to determine the current technical condition and to propose a functional adaptation. The outpost fort was of great strategic importance for the defense of the eastern border on the eve of the First World War at the end of the 19th century. 20th century A powerful fortification object was built according to the drawings of the outstanding military fortification engineer E. Totleben in 1860-1890. The head of the construction of the main structures of the fort was the engineer colonel Borisov, the modernization of the fort was carried out under the leadership of Belikov. The analysis of the latest researches and publications showed that the unique engineering and fortification complex of the Tarakan Fort-outpost is practically unexplored, without archaeological excavations and thorough research. The monument of defense architecture refers to the monument of military architecture of local importance and has great architectural value. In the process of research, the main factors of the construction of the Tarakan Fort were determined. The article examines the peculiarities of the layout and spatial arrangement of the fort in the village of Tarakaniv near the city of Dubno, Rivne region. Three stages of formation of the structure of the fort-outpost complex are defined. The functional and constructive solution of the "Dubno" fort outpost complex was considered and analyzed. The modern state of the defensive structures of the Tarakan Fort was studied. In order to preserve the monument of defensive architecture, a program of priority repair and restoration measures was developed and it was proposed to adapt the researched outpost fort to a tourist function.

Reliability modeling for repairable circular consecutive-[formula omitted]-out-of-[formula omitted]: F systems with retrial feature

In this paper, we consider a repairable circular consecutive-k-out-of-n: F retrial system, which can be used to simulate the intelligent closed recurring water cooling automation system in industrial production. We assume that the working time and retrial time of each component obey exponential distributions, and the repair time obeys a general distribution. Based on the generalized transition probability and the key component priority repair rule of the retrial system, the availability and reliability indices of the general repairable circular consecutive-k-out-of-n: F retrial system are derived by using the methods of supplementary variable and Laplace transform. Furthermore, we calculate the explicit expressions of the above indices when n and k are fixed at definite values in the system. The repair time is assumed to follow a Weibull distribution in examples demonstration, and the influence of various parameters on system reliability, steady-state availability and other indices are obtained. The sensitivity and relative sensitivity analysis of the steady-state availability, steady-state failure frequency and mean time to first failure (MTTFF) of the system are also performed.

USULAN PENINGKATAN KUALITAS PULP DENGAN MENGGUNAKAN METODE SEVEN TOOLS DAN NEW SEVEN TOOLS DI PT. IK

PT. IK is a company engaged in the manufacture of pulp and paper. Pulp production produced in each process sometimes does not meet the standard specifications of the quality set. The method used to solve the problem is the seven tools and the new seven tools. The research objectives were to determine priorities based on the type of defect, identify the cause of quality deviations, and determine the action to be taken to improve pulp quality. Priority repair on defects in the Blow Line Kappa Number, Ex Metso Press Soda Loss as Na2SO4, Post MCO2 Outlet Single Diffuser Residual Soda, and Ex Khamyr Press Soda Loss as Na2SO4. The causes of quality deviations include the lack of operator understanding of the SOP, the stages of the production process lacking supervision, the selection of raw materials that do not meet specifications, poor machine conditions, operator error or human error, and inappropriate chemical levels. Actions taken to improve the quality of the pulp are by conducting employee training, checking machines, continuously monitoring and controlling the production process, using work methods that are under with the SOP set by the company, environmental conditions that are under occupational safety and health, and optimizing operator performance.

Integrated Supply Chain Management and SCOR Model: A Strategic Approach for Small Sized Business

This research aims to develop a model of supply chain management and enhance the performance and value of Supply Chain ranging from upstream to downstream with. The location of the research that is in the village of Bonto Sinala sub district of Sinjai Regency, entire stock of Sinjai, South Sulawesi. Method of collecting data through observation, interview and Focus Group Discussion at the community involved in the efforts of Palm sugar, local traders as well as local government. The plan of implementation of the research done at some stage i.e. pre conditions, stage of data collection and data validation stage. Analysis of the data is done through the Implementation through the application of Supply Chain Operations Reference (SCOR) and the Analytical Hierarchy Process. The results showed that the performance of the business performance of Palm sugar is included in the category of average with a total of 46. The final value of the highest performance shows that are on the process of source and lowest performance on the process of return. This means that the process of hail return requires a priority repair effort on this Palm sugar.

GENERATION OF ELECTROMAGNETIC IMPULSES IN CLAYS DURING THEIR LOADING IN A LABORATORY ENVIRONMENT

The relevance of the research. Currently, filtration losses from water-bearing systems and controlling constructions are more than 30% which can be predominantly explained by unsatisfactory technical state of hydraulic engineering structures (HESs).
 Diagnostics of technical state of HESs of agricultural assignment, relating to a failure effect (responsibility) class CC-1 (i.e. minor effects), is performed usually with the help of visual inspection during inter-vegetation period when irrigation system (IS) is waterless. Searching for low-cost techniques to estimate state of soil HESs as well as determination of areas within them requiring for priority repair is a topical theoretical and practical task.
 Methods of the research. Geophysical method of natural impulse electromagnetic Earth’s field (NIEEF) may become such a technique; however, a problem of electromagnetic impulses (EMI) generation within soil masses is understudied despite the fact that they are the basic studied environment in the process of diagnostics of soil HESs of irrigation systems using the technique.
 To make theoretical and experimental substantiation of the NIEEF method to identify zones of filtration as well as zones of raised watering within the body of small soil geotechnical structures, nature of EMI amplitude changes while transferring uniaxial static load to clay samples in laboratory environment has been analyzed. Similar experiments using idealized model validate opportunity to apply the NIEEF technique for estimation of engineering state of HESs.
 Research results. The experiments were carried out using clay samples with natural moisture and those experienced additional watering. Soil porosity and soil porosity coefficient, being auxiliary characteristics to plot compression curves, were determined before compression tests and after them; standard calculation techniques were applied. The studies involved usual odometer; electromagnetic impulses were recorded with the help of МІЕМП-14/4 device (SIMEIZ series). The clay samples were loaded in accordance with actual pressure from plates and 4.2 m water layer within filled regulating pool (RP) which dimension was 4.789 kN/m2.
 Analysis of results of the compression tests has verified the following: increased EMI values correspond to maximum stress state of loose soil, and vice versa – their decrease is typical for relaxations of soil samples as well as for their additional watering. Hence, extreme values of EMI oscillation amplitudes are registered at the beginning of the compression tests when the sample experiences the most intensive compression. Peak excitation results insignificant “fall” of EMI number; then it’s slow increase is observed depending upon the decreased intensity of soil compression.
 Conclusions. The regularity makes it possible to substantiate theoretically the opportunity to apply rapid and low time-consuming as well as low-cost NIEEF method for diagnostics of engineering state of soil HESs. Previously, such experiments, concerning EMI generation, were carried out using crystalline rocks; loose rocks were involved for the first time.

DETERMINATION OF CRITICAL COMPONENTS FOR NAVIGATION RADAR USING FUZZY FMEA AND TOPSIS

In determining the critical components and repair priorities, traditional FMEA still have weaknesses, which puts the traditional FMEA factor severity, occurance and detection at the same level of importance, despite the fact that have different levels of interest and importance weight FMEA assessment teams are ignored. In this study integrated fuzzy method in which the FMEA factor severity, occurance and detection assessed in the form of linguistics. At this fuzzy method, the weight of the assessment team FMEA interests are taken into account. To do perangkingan and priority repair used method Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) based on criteria such as level of risk, economic costs, availability of spare parts, maintenance of economic safety and personal abilities. Application of Fuzzy and TOPSIS method in the FMEA to determine the critical components and priorities of the various alternative repair elected to damage components applied to Sperry Marine Navigation Radar system, which is expected by the application of this method can improve operational performance KRI to keep the areas of national jurisdiction

Exact Reliability Formula for Consecutive-k-Out-of-n Repairable Systems with r Repairmen

In this paper, consecutive-k-out-of-n repairable systems with r repairmen are studied. The systems are either circular (or) linear. We assume that both the working time, and the repair time of each component are exponentially distributed, and every component after repair is as good as new. Each component is either a key component or an ordinary component so we can adopt a priority repair rule for key components. By using the definition of transition probability, the state transition probabilities of the system are derived. Several fundamental reliability indices (including availability, the mean time to the first failure, reliability and failure rate) of the systems are obtained explicitly by using the Laplace transform technique. Finally, one example is shown to explain the model, and the methodology developed in this paper.

Analisis Kualitas Pelayanan Dalam Pelaksanaan Tera Dan Tera Ulang Alat Ukur, Timbang, Takar Dan Perlengkapannya (UTTP) Pada Bidang Perdagangan Dinas Koperasi, Perindustrian Dan Perdagangan Kabupaten Pacitan

The aims of this study are to measure the level of service quality and how to improve the quality of service execution in re-measurement tera and tera of UTTP in Commerce On duty Co-Operation, Industrial and Commerce Of Sub-Province of Pacitan. This research’s object is traditional market of Minulyo Pacitan as mains market in Sub-Province of Pacitan with 100 perpetrator people of sample as user/owner of UTTP (ukur,timbang, takar, dan perlengkapannya) with method intake of sampel by Convenience Sampling. The technique of collecting data uses questionnaires and direct interview. This research use qualitative analysis instrument test of validity and reliability to know valid or not and reliabel or not about the questions of questionnaire. Then, this research was done with Servqual method as instrument to do measurement of service quality. The measurement of service quality in Servqual method pursuant to five service dimension that is tangibles, responsiveness, realibility, assurance, and empathy. This research will be measured of gap 5 that is difference among performance and its expectation. Ad for yielded gap from a enumeration of Servqual 5 gap, -146 progressively lower him mount the quality of given service activities. Therefore, its needs the existence of priority repair of service quality, in this case is service of remeasurement tera and tera of UTTP at biggest difference or gap that is at variable of Responsiveness ( Energy Listen carefully) and attribute that has smallest difference that is – 0.44 at dimension question of variable of Tangibles ( Evidence Physical).
 Keyword: Quality Of Service, Method of Service Quality.

Improving web user satisfaction by ensuring usability criteria compliance

Purpose – The purpose of this paper is to improve and facilitate the work of developers and usability evaluators by providing an adaptable and effective support. A well-defined set of criteria and a range of evaluation values for each criterion as well as a complete websites classification, will guide evaluators. A usability percentage and a list of prioritized criteria, adapted to the type of website by a new usability metric, will help developers to improve the website. This improvement will increase the degree of web user satisfaction. Design/methodology/approach – Having established and validated a new usability evaluation framework, several usability tools have been analyzed. None of them totally fulfills the requirements of the evaluation framework. As a result of being unable to customize any of them, a new one has been developed. A study of 42 enterprise websites in an economically depressed region of Europe was performed using the new tool. This study involved 42 evaluators and 118 web users. Users have evaluated the websites before and after the redesign. A end-user computing satisfaction model-based questionary was used to collect data about end-user satisfaction. The results validate the proposal. Findings – The study confirms that the proposed tool provides valuable information during the process of web development, evaluation and redesign. In adittion, it reveals that improving websites usability by ensuring criteria compliance has a positive effect on web users satisfaction. Originality/value – Unlike previous purposes, the proposed tool allows to evaluate any type of website with a well-defined set of evaluation criteria and specific criteria values. As outcomes, the tool provides the website usability degree and a list of criteria ordered by priority repair. These results are adapted to the specific type of website. This makes easier and more effective the redesign of the evaluated website.

Asymptotic optimality of RESTART estimators in highly dependable systems

We consider a wide class of models that includes the highly reliable Markovian systems (HRMS) often used to represent the evolution of multi-component systems in reliability settings. Repair times and component lifetimes are random variables that follow a general distribution, and the repair service adopts a priority repair rule based on system failure risk. Since crude simulation has proved to be inefficient for highly-dependable systems, the RESTART method is used for the estimation of steady-state unavailability and other reliability measures. In this method, a number of simulation retrials are performed when the process enters regions of the state space where the chance of occurrence of a rare event (e.g., a system failure) is higher. The main difficulty involved in applying this method is finding a suitable function, called the importance function, to define the regions. In this paper we introduce an importance function which, for unbalanced systems, represents a great improvement over the importance function used in previous papers. We also demonstrate the asymptotic optimality of RESTART estimators in these models. Several examples are presented to show the effectiveness of the new approach, and probabilities up to the order of 10−42 are accurately estimated with little computational effort.

Clinical study of femoral peel-off lesions in acute posterolateral corner injuries

Objective To determine the incidence of clinically common acute avulsions of the popliteus tendon (PT) and the lateral collateral ligament (LCL) of the femur (peel-off lesion) in knees with multiple injured ligaments.Methods A retrospective review of 48 acute grade 3 posterolateral corner (PLC) knee surgeries was conducted.All office evaluations were reviewed to determine the demographic data,tear description,preoperative MRI examination,physical examination under anesthesia,intraoperative arthroscopic findings and surgical techniques.Results In total,19 patients were surgically verified as having femoral peel-off lesions as a portion of a series of multiple pathologic findings.Tear patterns were typically categorized into 3 patterns:isolated PT tear (pattern 1,4 patients),combined PT and LCL tears (pattern 2,8 patients) and complex tears (associated intrasubstance and/or fibular-based injuries,pattern 3,7 patients).Seventeen of the 19 patients underwent preoperative MRI examination,which demonstrated conclusive signs of femoral insertion separation and discontinuity in 13 patients (76%) and inconclusive signs of femoral insertion separation.Examination under anesthesia (EUA) revealed that for the 4 patients with pattern 1 injuries,the tibial external rotation increases were all greater than 10°.For the 15 patients with pattern 2 and 3 injuries,the yarus instability was as follows:grade 3 in 8 patients,grade 2 in 2,grade 1 in 1,and negative in 4.External rotation increases were greater than 10° in 12 patients and less than 10° in 3.Seventeen of the 19 patients were inspected with an arthroscope prior to PLC surgery:of these patients,94% had acute avulsion findings and positive lateral gutter drive-through sign;8 patients were repaired with recess or reattachment procedures;6 patients were primarily reconstructed;4 patients were treated with combined repair and reconstruction;and 1 patient was left untreated for secondary reconstruction due to priority repair for concurrent patellar tendon rupture.Conclusion For adequate clinical identification,we recommend a comprehensive diagnostic protocol,including MRI,physical examination and arthroscopic inspection,to avoid underdiagnosis of the lesion in multiple-ligament injured knees.The lateral gutter arthroscopic evaluation is particularly sensitive for detecting the lesion. Key words: Arthroscopy; Knee injuries; Ligaments; Treatment outcome

Exact Reliability Formula for Consecutive-$k$-Out-of-$n$ Repairable Systems

In this paper, consecutive-k -out-of-n repairable systems are studied. We assume that both the working time, and the repair time of each component are exponentially distributed, and every component after repair is as good as new. Each component is either a key component, or an ordinary component so we can adopt a priority repair rule for key components. First, the state transition probabilities as well as their Laplace transforms for the systems are derived. Second, several fundamental reliability indices (including availability, the mean time to the first failure, reliability, and the rate of occurrence of failure) of the systems are obtained explicitly. Finally, one example is shown to explain the model, and the methodology developed in this paper.

RESTART simulation of non-Markov consecutive- k-out-of- n: F repairable systems

The reliability of consecutive- k-out-of- n: F repairable systems and ( k−1)-step Markov dependence is studied. The model analyzed in this paper is more general than those of previous studies given that repair time and component lifetimes are random variables that follow a general distribution. The system has one repair service which adopts a priority repair rule based on system failure risk. Since crude simulation has proved to be inefficient for highly dependable systems, the RESTART method was used for the estimation of steady-state unavailability, MTBF and unreliability. Probabilities up to the order of 10 −16 have been accurately estimated with little computational effort. In this method, a number of simulation retrials are performed when the process enters regions of the state space where the chance of occurrence of a rare event (e.g., a system failure) is higher. The main difficulty for the application of this method is to find a suitable function, called the importance function, to define the regions. Given the simplicity involved in changing some model assumptions with RESTART, the importance function used in this paper could be useful for dependability estimation of many systems.

A general model for consecutive- k-out-of- n: F repairable system with exponential distribution and ( k−1)-step Markov dependence

In this paper, a general model for consecutive- k-out-of- n: F repairable system with exponential distribution and ( k−1)-step Markov dependence is introduced. The lifetime of a component is an exponential random variable, its parameter depends on the number of consecutive failed components that precede the component. The repair time is also an exponential random variable. A priority repair rule on the basis of the system failure risk is adopted. Then the transition density matrix of the system is determined. Some reliability indices, including the system availability, rate of occurrence of failures and reliability are evaluated accordingly. For the demonstration of the model and methodology, a linear system example and a circular system example are investigated.

A Production/Inventory System Subject to Failure with Limited Repair Capacity

We consider a production/inventory system consisting of M machines and K (K≤M) repair crews in which machines are subject to time dependent failures. The repair operations on each machine require one repair crew during the whole operation. In this production/inventory system, each machine is assigned to produce a different item according to a make-to-stock routine. Inventories of each item service a Poisson demand process, and the unsatisfied demands are lost. The objective is to minimize the sum of the average holding and lost-sales penalty costs. We formulate the joint problem of (1) allocating the limited number of repairmen to failed machines and (2) deciding how much finished goods inventory to keep as a Markov decision process. We show that the optimal policy has a very complicated structure. We introduce two models to compute optimal base-stock policies in systems with identical machines, where first break first repair (FBFR) or preemptive priority (PPRI) repair policies are used. Then we present two heuristics to perform the same optimization analysis in systems with different machines. Finally, we compare the combination of the optimal base-stock policy (as the production policy) and the FBFR and PPRI policies (as the repair policies) to the optimal dynamic policy, and through numerical examples we show that this integration creates a solution that is close to the optimal dynamic policy. The results indicate that simple policies for determining finished goods inventory levels and repair crew assignment to failed machines can work well as long as the two problems are addressed in a coordinated manner.

A two unit priority redundant system with three modes and correlated failures and repairs

This paper considers a two dissimilar units priority redundant system with three modes. One of the units has a priority operative mode and the other has a priority repair mode. Assuming that the joint distribution of failure and repair times is exponentially bivariate, some reliability characteristics useful to system managers have been obtained. Results for a system with two similar units are obtained as a particular case.

Priority repair and dispatch policies for reparable-item logistics systems

In this article we present the results of a simulation study concerned with reparable electronic equipment on military aircraft. Past studies in the literature have considered priority rules at the repair depot, and one study considered an allocation scheme for distributing repaired items to bases. In this study, we examine the use of a priority rule for sequencing items at a repair depot in conjunction with a priority rule for allocating repaired items to bases. We examine, among other things, the conditions under which it is favorable to consider priority rules. The results indicate that the important variables are the efficiency of the lateral resupply system, the initial allocation of spare stock, and the time it takes to ship items from the depot to bases. The objective throughout is to minimize the expected number of aircraft grounded due to lack of parts.