Добірка наукової літератури з теми "Statistical characteristics of operational processes indicators"

The most important characteristics of the processes efficiency in aircraft equipment technical operation are the operational reliability characteristics. High reliability of aviation equipment is the main condition for its readiness, efficiency and safety.
 The aircraft equipment reliability is its ability to perform specified functions, maintaining during some time the values of the established flight and technical and operational indicators within the specified limits, which correspond to the specified modes and conditions of use, maintenance, repair, storage and transportation.
 Despite the quick scientific and technological progress in aviation, the problem of flights safety has become extremely acute in the present time. Empirical data statistical processing is an urgent task in monitoring of the Ukrainian Armed Forces aircrafts operation and determining trends in maintenance and repair, areas of modernization of armaments and military equipment.
 The subject of the work is the analysis and system approach based on the developed estimation technique of aviation equipment reliability indicators. The results of determined helicopters and their functional systems reliability are presented. The trend and the main reasons for the change in reliability indicators for 2016-2019 are determined.
 The main purpose of reliability analysis is to determine the causal relationships between quantitative and qualitative reliability indicators and the level of flight safety that lead to aviation accidents.
 Statistical information in the form of fault records and reports, where the generalized operational data are sent by the State aviation units according to the methodical recommendations.
 Indicators analysis of operational reliability and flights safety for helicopters according to statistical data of failures, damages and incidents is done. Moreover, the trend and the main reasons for the helicopters reliability indicators changes for the period 2016-2019 are defined.
 The results of research are presented in the final tables, which show the average values of operational reliability, flight safety and the level of combat flight task for different types of helicopters in all specialties.
 The causes of malfunctions that affect the level of operational reliability, flight safety and non-fulfillment of the flight task on helicopters for the period 2015-2019 were taken into account.
 According to the statistics analysis of the malfunctions reported causes , it is determined that the total number of reported malfunctions on different types of helicopters in 2019 increased by 11.0% compared to 2018, compared to 2017 by 43.7%, compared to 2016 by 58.4%, compared to 2015 by 70.0%.

The need to assess the technological systems for biogas production is due to the need to determine their operational, technological, technical, economic and design characteristics. The aim of the study is to develop a methodology for assessing the operational indicators of the reliability of equipment for flow-technological lines of biogas plants. The main element of the technological equipment for biogas production, which provides the quantitative and qualitative composition of nutrients in the storage bins of biogas plants, is drum grinders - mixers, the hourly performance of which determines the cycle of the flow-technological line. All other technological operations must be coordinated with the main one in terms of quality indicators, rhythm of work and productivity. To assess the operational and technological characteristics, it is advisable to use productivity, flow rate and reliability. The reliability of flow-technological lines of biogas plants, which is the result of the operation of the entire complex of technological equipment, depends not only on the reliability indicators of these machines and their interaction processes, but also on the number and type of their connections. A comprehensive indicator of the reliability of a biogas production line is the availability factor. The main methods of increasing the reliability of biogas plant lines are: reducing the total amount of equipment in the technological line; use of equipment with higher reliability; unloaded and loaded redundancy of less reliable equipment; creation of multi-section systems. It has been established that the organizational and technological reliability of stream biogas production processes is ensured by choosing a rational structure and quantitative composition, as well as coordinating equipment in bioenergy complexes and technological lines according to basic parameters, taking into account their statistical features.

Subject. The article considers the development of a digital decision-making platform to manage business processes, based on the formation of an integral indicator of rating evaluations of qualitative and quantitative characteristics of the stated problem. Objectives. The aim is to design an algorithm for making managerial decisions on problems arising during the implementation of operational business processes at agricultural enterprises. Methods. We employ methods of analysis and synthesis, deduction and induction, and the statistical analysis. Results. We formulated main problems faced by an agricultural enterprise during the implementation of business processes, developed an information base to analyze and interpret the given problem, carried out rating evaluations of initial information to construct a functional expression of the correspondence of specific weights of declared indicators and their significance in the process of making a specific decision. The paper determines the reliability of final expression of the function as a result of the rating of initial data. Conclusions. The developed platform is aimed at streamlining the management decision-making process, reducing costs and operational efficiency of the management system. The findings will help improve the efficiency and responsiveness of decision-making.

The operational efficiency of measuring equipment (ME) is important in determining the cost of maintaining ME. To characterize the operational efficiency of the ME, an efficiency indicator has been introduced, an increase of which will reduce costs caused by the release of defective products due to the use of ME with unreliable indications. Over time, the ME parameters change under the influence of external factors and the ME aging processes inevitably occur, as a result of which the parameters of the ME metrological service system change. Therefore, in the general case, the parameters of the metrological maintenance system of ME should be considered as random variables. Accordingly, the efficiency indicator of measuring instruments is also a random variable, for the determination of which it is advisable to apply the methods of mathematical statistics and computer simulation. The performance indicator depends on the parameters of the metrological maintenance ME system, such as the calibration interval, the time spent by the ME on metrological maintenance, and the likelihood of ME failure-free operation. As a random variable, the efficiency indicator has a certain distribution function. To determine the distribution function of the efficiency indicator and the corresponding statistical characteristics, a computer simulation method was used. A study was made of the influence on the indicator of the effectiveness of the parameters of the metrological maintenance system ME (interesting interval, the failure rate of ME). The value of the verification interval and the failure rate of MEs varied over a wide range typical of real production. The time spent by ME on metrological services is considered as a random variable with a normal distribution law. To obtain random numbers with a normal distribution law, the Box-Muller method is used. After modeling, the statistical processing of the obtained results was done. It is shown that in real production, the efficiency indicator has a normal distribution law and the value of the efficiency indicator with an increase in the calibration interval does not practically change.

The article states that a high level of analytical support should be provided during the development of national security policy. Therefore, there is a need to create new conceptual approaches based on the methodology of systems analysis and information technology, including big data. This makes it possible to forecast and make decisions in the field of national security with the help of appropriate indicators and indices.Attention is drawn to the fact that when monitoring national security with the help of indicators, indices and their threshhold values, it is important to monitor the dynamics of processes taking place in different areas of national security, and not by individual events. This approach makes it possible to consider the management of the national security system with the help of threshhold values and indicators as a regulatory activity.Attention is drawn to the fact that traditionally the analysis in the field of national security was based on the data of the security and defense sector. These data concerned the events that had already taken place. However, borrowing external data opens up greater opportunities for moving along the chain of analytical research: from assessing past events to reliably predicting future challenges and threats to national security. Therefore, the process of making strategic decisions using Big Data technology can be organized using the pyramid DIKW. The use of indicators and indicators of national security in the three-level system of national security is considered. The goals and objectives of the strategic, tactical and operational levels are determined by current legislation and the higher (strategic) level.The emphasis is on the fact that Big Data provides additional context by integrating external data to turn data into information. With the help of appropriate doctrines, concepts and strategies, this information can be further improved. Given the differences in the rate of change at all levels of the hierarchy of national security, we can conclude that all levels are responsible for implementing main directions of the state national security policy, although they are based on different national security indicators, their statistical characteristics, expert assessments, thresholds.

The use of new energy-saving technologies has led to the significant development of vibration machine designs and their widespread use. In the course of their operation, the question of efficiency and reliability of the use of this type of machines is rather acute, related to the availability and possibility of using reserves of its operation. Machines of this type must meet the requirements of quality and reliability in order to fulfill their official purpose. Due to the design features and the complexity of the processes occurring during their work, analytical calculations of durability and reliability in the classical version are quite approximate in nature and do not provide the necessary accuracy. So the question of reliability and durability of vibrating equipment is urgent. The questions of reliability estimation of vibrating machines were dealt with by the following scientists: Iskovich-Lototsky RD, Obertyukh R., Sevastyanov IV, Kanarchuk VE, Dzhratratano D.J. etc. The techniques they offer are virtually indistinguishable from those adopted in general engineering. The publication proposes a technique for evaluating efficiency and reliability based on the use of quantitative characteristics of probabilistic and statistical nature. Such indicators for quantifying the reliability and reliability are: probability of failure, failure rate, failure rate, failure time. These indicators are one of the most important in the technical diagnostics of the operation of vibrating machines and the estimation of their residual life. The basic calculation, dependencies, analysis of laws are given.

Introduction. The abolition of public credit institutions in the first half of the 19th century meant that following after the peasant reform, private landowners were forced to rely entirely on their ability to conduct economic activities, they desperately needed the money demanded for the capitalist modernization of their estates. It was important under such circumstances the appearance in the mid-1860s of private land banks that have granted land collateral loans. Materials and Methods. The study of the claimed problem required the involvement of a number of historical and economic methods: historical, statistical and quantitative. At the same time, the question of the amount of debt owed to private land banks was examined on the basis of a comprehensive analysis of statistical data on land credit published by a committee of congresses of representatives of Russian land credit institutions. Results. The article analyzes the main indicators of the activity of the joint-stock land banks in the first two decades of their operation, considers the characteristics of the establishment and development of the private land credit system, the volume of loans issued, the size of the mortgaged land, the amount of the loans are shown by their regional characteristics. Discussion and Conclusions. Set up in mid-nineteenth century the system of equity land credit, which focuses on the granting of land mortgages by private landowners, has played an important role in the processes of land ownership mobilization and the development of capitalism in the agricultural sector. Private credit institutions were one of the most important components of the land credit system, and the activities of these institutions in the territory of the governorate in question resulted in: that almost a quarter of all privately owned land had been deposited in them.

The topic of this paper is analyzing the results of field studies of a tractor with an elastic damping mechanism in a power drive and its operational efficiency assessment in comparison with a serial tractor. The subject of the research is a tractor with an elastic damping mechanism in a power drive as part of a plowing unit with a mounted plow. The purpose of this work is a detailed analysis of the influence of the parameters of the elastic-damping mechanism on the performance of a tractor with a plow. Carrying out such studies makes it possible to obtain new experimental data on the operation of the elastic damping mechanism in-stalled in the power drive of a tractor when aggregated with a plow. The control experiments were carried out in the same field during the summer and autumn peri-ods of one year. The benchmark for comparative experiments was the same tractor, but with a blocked elastic damping mechanism (for brevity, it is called “serial”). The results were processed on a personal computer using a software package. To analyze energy efficiency, a conditional classifi-cation of sample variability based on the coefficient of variation was used. Spectral analysis was performed to study numerical slip data. The indicators of the energy assessment show that the unit with an elastic damping mechanism in the power drive of the tractor has better performance (travel speed, productivity and fuel consump-tion per hectare) than a similar unit with a more rigid transmission. The elastic damping mechanism creates more favorable conditions for the formation of the nature of the load of the nodes, with un-steady and steady-state modes of motion. Statistical analysis of numerical data on slipping showed that the use of the mechanism makes it possible to reduce the mathematical expectation of slipping. Analysis of spectral characteristics indicates that the elastic-damping mechanism absorbs frequen-cies, being a filter when aggregated with various tools. Everything mentioned above indicates a sig-nificant improvement in the characteristics of the unit when using an elastic damping mechanism.

The introduction of methods for timely diagnostics of internal combustion engines allows maintaining the environmental indicators of the car fleet at the highest level. (Research purpose) The research purpose is in increasing the reliability of diagnostics of internal combustion engines by using data obtained by selective sampling of exhaust gases. (Materials and methods) Informational, mathematical and experimental research methods, including methods for statistical processing of results and analysis of data obtained during experiments were used during the study. (Results and discussion) The main systems that affect the environmental performance of internal combustion engines has been identified: the fuel supply system, the ignition system and the exhaust gas neutralization system. The article describes a generalized mathematical model for calculating the characteristics of exhaust gases. Authors conducted operational tests on 35 internal combustion engines with justification of their number according to standard methods. The actual value of diagnostic parameters was processed into relative percentages for drawing a nomogram. A zero value has been set for the reference state of the elements specified by the manufacturer. (Conclusions) It was found that the dominant number of failures accounted for internal combustion engines, in detail: the ignition system produces 15-25 percent of failures, the power system produces 30-44 percent, the exhaust system produces 10-15 percent. It was found that for unambiguous identification of any combination of factors, it is necessary to have output values of at least three evaluation criteria. It was found that the most sensitive parameters for evaluating the technical condition of the three systems are: changes in the engine crankshaft speed, the parameters of exhaust gas toxicity, CO, CO2, CH, O2 when providing test modes (operation of the internal combustion engine on 1 cylinder at 20 and 40 percent of the throttle opening). The article describes designed a gasoline engine loader for the implementation of diagnostic modes and control of diagnostic parameters, that allows to create operating loads with an accuracy of 0.1 percent.

Purpose The increased complexity of global supply chains and its inherent risk requires the re-evaluation of the SCRM discipline as a source of value creation for shareholders. This paper aims to unveil the areas that require more focus considering the point of view of Chinese manufacturers, and following a social constructivist approach oriented to fashion organizations outsourcing to China, unveil the elements driving the point of SCRM strategies. Design/methodology/approach The authors studied the existing body of knowledge related to SCRM and developed a model to quantify the influence of macro and micro risk factors to the different operations performance indicators. This model was used in a survey to 61 Chinese manufacturers of fashion products, while at the same time, an interview to 20 members of the SC group of fashion companies around the globe was conducted to understand the qualitative and quantitative elements shaping their SCRM initiatives. Findings The study shows that, while supply, manufacturing and demand risk remain as the main factors hindering value creation in the industry, the addition of the manufacturer’s perspective proves that other elements that are less evident to the customer, such as macro-social and micro-infrastructure (transportation, financial and information), require more attention. Additionally, it was noted that the influence of the different risk factors is different for the different performance indicators of quality, speed, cost, dependability and flexibility. Finally, it shows that current SCRM programs tend to be simplified methods of trial and error, fed with incomplete KPIs, shaped by the experience and priorities of dominant stakeholders and prompt to potential agency costs and focused on the short term. Research limitations/implications The focus on the fashion industry led to relatively small sample sizes for surveys and interviews. Although some patterns are identified, studies with larger sample sizes could facilitate the statistical analysis of unique characteristics in the different sub-groups. Additionally, the use of cross-sectional research designs that include survey techniques has the limitation of not explaining processes over time. Future reference to this work can be complemented with a new study to unveil the latest priorities. Practical implications This study shows that, to create value, fashion organizations first need to determine the operational elements that create value for them and then focus their limited resources on the risk elements that have proved more influence. The authors offer a systematic framework to measure the risk associated with global outsourcing; it can be used by organizations outsourcing globally to make strategic decisions, including potential outsourcing locations, to allocate resources across categories and to evaluate changes over time. Finally, the interview with SC practitioners shows that, to advance toward its objective of value creation, the SCRM discipline requires cross-collaboration and a holistic approach supported by more systematic processes that can reduce bias and potential agency costs. Originality/value This study offers insights about contemporary factors affecting the value creation function for fashion organizations outsourcing production to China and a more holistic approach vs other studies by including: a wider and more relevant categorization of risk factors, the perspective of Chinese manufacturers and the view of SC practitioners around the world. This study also develops a model to explain the cycle of SCRM in fashion organizations and the most common traps hindering its execution.

Дисертаційна робота присвячена вирішенню актуальної науково-технічної задачі щодо розроблення методів визначення статистичних характеристик процедур діагностування технічного стану наземних засобів аеронавігації з метою підвищення ефективності систем експлуатації наземних засобів аеронавігації. Удосконалено метод визначення рівня експлуатаційних витрат під час діагностування та відновлення працездатності наземних засобів аеронавігації, який на відміну від існуючого базується на використанні щільностей розподілу ймовірностей витрат експлуатаційних ресурсів, запропонованої оптимізаційної функції, використанні функціональної залежності додаткових витрат у випадках, коли запланований обсяг витрат на ремонт є недостатнім. Удосконалено метод знаходження ЩРІ часових витрат на діагностування та відновлення працездатності НЗА, що на відміну від існуючого методу: заснований на використанні матричного апарату представлення аналітичних співвідношень, на використанні ЩРІ часових витрат окремих контрольно-вимірювальних операцій та застосуванні аналітичних співвідношень, що дозволяють проводити оцінку ЩРІ вартісних та трудомісткістних витрат на основі часових витрат на діагностування та відновлення працездатності. У роботі вперше розроблено метод визначення оптимальних значень умовних ймовірностей помилок першого та другого роду за умов використання аналітичних співвідношень, що були отримані під час розроблення методу визначення статистичних характеристик часових, вартісних та трудомістких робіт діагностування НЗА, тобто базується на використанні відповідних ЩРІ показників ефективності процедур діагностування.<br>The thesis is devoted to the solution of the actual scientific and technical problem concerning methods development for determining statistical characteristics of p procedures for diagnostics of the technical condition for ground air navigation equipment for the purpose of efficiency increase for corresponding operation systems. Improved method for determining the level of operation costs when diagnosing and restoring ground air navigation equipment, which in contrast to the existing is based on the use of probability density function of operation resources, the proposed optimization function, the use of functional dependence of additional costs in cases where planned costs are insufficient. The method of finding the time costs of diagnosing and restoring the ground air navigation equipment, which in contrast to the existing method: based on the use of matrix apparatus for representing analytical equations, the use of time costs of individual control and measuring operations and the use of analytical ratios that allow to estimate probability density function of costs and labor-intensity based on time spent on equipment diagnostics and repair. For the first time, a method of determining the optimal values of conditional probabilities of errors of the first and second kind under the conditions of using analytical ratios obtained during the synthesis of the method of determining statistical characteristics for time, costs and labor-intensity is considered.

Hard coal mining is characterised by features that pose numerous challenges to its current operations and cause strategic and operational problems in planning its development. The most important of these include the high capital intensity of mining investment projects and the dynamically changing environment in which the sector operates, while the long-term role of the sector is dependent on factors originating at both national and international level. At the same time, the conditions for coal mining are deteriorating, the resources more readily available in active mines are being exhausted, mining depths are increasing, temperature levels in pits are rising, transport routes for staff and materials are getting longer, effective working time is decreasing, natural hazards are increasing, and seams with an increasing content of waste rock are being mined. The mining industry is currently in a very difficult situation, both in technical (mining) and economic terms. It cannot be ignored, however, that the difficult financial situation of Polish mining companies is largely exacerbated by their high operating costs. The cost of obtaining coal and its price are two key elements that determine the level of efficiency of Polish mines. This situation could be improved by streamlining the planning processes. This would involve striving for production planning that is as predictable as possible and, on the other hand, economically efficient. In this respect, it is helpful to plan the production from operating longwalls with full awareness of the complexity of geological and mining conditions and the resulting economic consequences. The constraints on increasing the efficiency of the mining process are due to the technical potential of the mining process, organisational factors and, above all, geological and mining conditions. The main objective of the monograph is to identify relations between geological and mining parameters and the level of longwall mining costs, and their daily output. In view of the above, it was assumed that it was possible to present the relationship between the costs of longwall mining and the daily coal output from a longwall as a function of onerous geological and mining factors. The monograph presents two models of onerous geological and mining conditions, including natural hazards, deposit (seam) parameters, mining (technical) parameters and environmental factors. The models were used to calculate two onerousness indicators, Wue and WUt, which synthetically define the level of impact of onerous geological and mining conditions on the mining process in relation to: —— operating costs at longwall faces – indicator WUe, —— daily longwall mining output – indicator WUt. In the next research step, the analysis of direct relationships of selected geological and mining factors with longwall costs and the mining output level was conducted. For this purpose, two statistical models were built for the following dependent variables: unit operating cost (Model 1) and daily longwall mining output (Model 2). The models served two additional sub-objectives: interpretation of the influence of independent variables on dependent variables and point forecasting. The models were also used for forecasting purposes. Statistical models were built on the basis of historical production results of selected seven Polish mines. On the basis of variability of geological and mining conditions at 120 longwalls, the influence of individual parameters on longwall mining between 2010 and 2019 was determined. The identified relationships made it possible to formulate numerical forecast of unit production cost and daily longwall mining output in relation to the level of expected onerousness. The projection period was assumed to be 2020–2030. On this basis, an opinion was formulated on the forecast of the expected unit production costs and the output of the 259 longwalls planned to be mined at these mines. A procedure scheme was developed using the following methods: 1) Analytic Hierarchy Process (AHP) – mathematical multi-criteria decision-making method, 2) comparative multivariate analysis, 3) regression analysis, 4) Monte Carlo simulation. The utilitarian purpose of the monograph is to provide the research community with the concept of building models that can be used to solve real decision-making problems during longwall planning in hard coal mines. The layout of the monograph, consisting of an introduction, eight main sections and a conclusion, follows the objectives set out above. Section One presents the methodology used to assess the impact of onerous geological and mining conditions on the mining process. Multi-Criteria Decision Analysis (MCDA) is reviewed and basic definitions used in the following part of the paper are introduced. The section includes a description of AHP which was used in the presented analysis. Individual factors resulting from natural hazards, from the geological structure of the deposit (seam), from limitations caused by technical requirements, from the impact of mining on the environment, which affect the mining process, are described exhaustively in Section Two. Sections Three and Four present the construction of two hierarchical models of geological and mining conditions onerousness: the first in the context of extraction costs and the second in relation to daily longwall mining. The procedure for valuing the importance of their components by a group of experts (pairwise comparison of criteria and sub-criteria on the basis of Saaty’s 9-point comparison scale) is presented. The AHP method is very sensitive to even small changes in the value of the comparison matrix. In order to determine the stability of the valuation of both onerousness models, a sensitivity analysis was carried out, which is described in detail in Section Five. Section Six is devoted to the issue of constructing aggregate indices, WUe and WUt, which synthetically measure the impact of onerous geological and mining conditions on the mining process in individual longwalls and allow for a linear ordering of longwalls according to increasing levels of onerousness. Section Seven opens the research part of the work, which analyses the results of the developed models and indicators in individual mines. A detailed analysis is presented of the assessment of the impact of onerous mining conditions on mining costs in selected seams of the analysed mines, and in the case of the impact of onerous mining on daily longwall mining output, the variability of this process in individual fields (lots) of the mines is characterised. Section Eight presents the regression equations for the dependence of the costs and level of extraction on the aggregated onerousness indicators, WUe and WUt. The regression models f(KJC_N) and f(W) developed in this way are used to forecast the unit mining costs and daily output of the designed longwalls in the context of diversified geological and mining conditions. The use of regression models is of great practical importance. It makes it possible to approximate unit costs and daily output for newly designed longwall workings. The use of this knowledge may significantly improve the quality of planning processes and the effectiveness of the mining process.

Organizations are increasingly dependent on information systems, and they invest dearly on systems to integrate disparate business functions, automate business processes, and support operations in order to sustain business and survive in a competition-intensive business environment. However, such systems have in many occasions failed fully or partially. The lack of “fit-to purpose” seems to be the common factor among most of the failed cases. This suggests that such systems are not selected, implemented, configured, or supported based on a proper analysis and understanding of the organization structure and hierarchy, business functions, business processes, and business environment. Evidently, the majority of organizations tend to emphasize system specifications that match their operational and tactical requirements, with little attention given to strategic requirements, culminating in issues with strategic planning and decision making. This chapter uses a survey and simple model based on the characteristics and competitiveness indicators of strategic information systems (SIS) to examine the impact of such systems on the business performance in 16 medium to large Arab organizations. The study concludes with an emphasis of the importance of SIS to help organizations achieve excellence and competitive advantage and realize business objectives and goals.

Due to the multiple transformation of electrical energy, the rated capacity of power transformers can be 8 or more times the rated generation capacity. Therefore, the state of reliability of power transformers, their parameters and characteristics affecting on the reliability and efficiency of power networks, electrical production facilities, and electrical equipment of consumers. High indicators of operational reliability should be provided by the corresponding level of quality of design of power transformers both at a stage of development of tender offers, and during preparation of production of new or modernized types of power transformers. Im-proving approaches to design and increasing the accuracy of design data requires the use of modern specialized software for spatial modeling of electromagnetic and elec-tro-thermal processes in testing and rated modes of operation based on 3D geometric models of parts, assemblies, systems in the active parts of power transformers. To improve the design quality of power transformers, a unitary structure is proposed, which combines tuples of design data of certain types of power transformers. Crea-tion of a unitary structure of power transformer projects for the production program of the enterprise provides a significant time reduction to develop projects of new types of power transformers by importing the generated design data of the same parts, components, systems from previously developed power transformer projects. Application of unitary structure of power transformers projects allows to reduce time for creation and import of detailed 3D geometric model of power transformer in structure of specialized software of field modeling of electromagnetic and electro-thermal processes. This allows to significantly reduce the cost of design preparation of production, increase the accuracy of design data and implement design solutions to increase the level of reliability and efficiency of operation of power transformers. Therefore, the design data for the unavailable parts, components, elements of individual systems in a transformer are displayed in the corresponding design tuple "zero" elements. For development of projects of new types of power transformers, import of the structured design data of identical details, knots, systems of earlier developed projects of power transformers is carried out. Updating the unitary structure of power transformers is provided by supplementing the existing unitary structure with a tuple of design data of a new type of power transformer. This provides a significant reduction in design time and increase the accuracy of determining new design data.

Condition monitoring assesses the operational health of rotating machinery, in order to provide early and accurate warning of potential failures such that preventative maintenance actions may be taken. To achieve this target, manufacturers start taking on the responsibilities of engine condition monitoring, by embedding health monitoring systems within each engine unit and prompting maintenance actions when necessary. Several types of condition monitoring are used including oil debris monitoring, temperature monitoring and vibration monitoring. Among them, vibration monitoring is the most widely used technique. Machine vibro-acoustic signatures contain pivotal information about its state of health. The current work focuses on one part of the diagnosis stage of condition monitoring for engine bearing health monitoring as bearings are critical components in rotating machinery. A plethora of signal processing tools and methods applied at the time domain, the frequency domain, the time-frequency domain and the time-scale domain have been presented in order to extract valuable information by proposing different diagnostic features. Among others, an emerging interest has been reported on modeling rotating machinery signals as cyclostationary, which is a particular class of non-stationary stochastic processes. A process x(t) is said to be nth-order cyclostationary with period T if its nth-order moments exist and are periodic with period T. Several tools, such as the Spectral Correlation Density (SCD) and the Cyclic Modulation Spectrum (CMS) can be used in order to extract interesting information concerning the cyclic behavior of cyclostationary signals. In order to measure the cyclostationarity from order 1 to 4, concise and global indicators have been proposed. However, in a number of applications such as aircraft engines and wind turbines the characteristic vibroacoustic signatures of rotating machinery depend on the operating conditions of the rotational speed and/or the load. During the last decades fault diagnostics of rotating machinery under variable speed/load has attracted a lot of interest. The classical cyclostationary tools can be used under the assumption that the speed of machinery is constant or nearly constant, otherwise the vibroacoustic signal becomes cyclo-non-stationary. In order to overcome this limitation a generalization of both SCD and CMS functions have been proposed displaying cyclic Order versus Frequency. The goal of this paper is to propose a novel approach for the analysis of cyclo-nonstationary signals based on the generalization of indicators of cyclostationarity in order to cover the speed varying conditions. The proposed indicators of cyclo-non-stationarity (ICNS) are expected to summarize the information at various statistical orders and at lower computational cost compared to the Order-Frequency SCD or CMS. This generalization is realized by introducing a new speed-dependent angle averaging operator. The effectiveness of the approach is evaluated on an acceleration signal captured on the casing of an aircraft engine gearbox, provided by SAFRAN, in the frames of SAFRAN contest which took place at the Surveillance 8 International Conference.

The scientific reliability assessment is important for motor-driven compressor units, to evaluate the reliability standard, find the performance deficiency and provide references for operation and maintenance. Besides, it can reduce the test costs and accelerate the development process. Classical reliability assessment method is not suitable for the complex and reliable equipment, like motor-driven compressor units, because it is faced with the challenge of application of the multi-source information. A multi-source information based reliability assessment method is proposed in this paper. The fusion resources of this method consist of design information and operation &amp; maintenance information. Component based and function based reliability assessment can be completed using component tests and design information. While quality evaluation based and life model based reliability assessment can be completed using operation information mainly. Finally, the unit reliability can be assessed by fusing the characteristic parameters above based on D-S evidence theory. A case study is conducted to evaluate a 20MW-class motor-driven compressor unit by this method. There are four information resources, component tests, design information, operation data and simulation data in the case. The unit reliability is assessed as 99.32% by the fusion of four reliability assessment results, acquired at different aspects. This assessment result is validated by the statistical assessment result based on long-term shutdown reports. This application points out the existing weakness in the motor-driven compressor unit and indicates directions for improving the design and operation technology. It reveals that this reliability assessment result can provide support for making a new production plan and strengthen construction of data network. Meanwhile, it has good expansibility, which may be used in more fields.

Purpose – digitalization of business processes, cultural backgrounds and consequences on behavioral differences make a direct impact on customer purchase behavior across different countries. The main aim of this paper is to analyze the effect of the economic situation in the selected countries regarding the e-commerce business. Research methodology – first, the paper presents a theoretical model for customer purchase behavior and the develop-ment of the theory in the B2C e-commerce context. Second, it is analyzed the main aspects of shopping behavior in se-lected countries. Findings – a difference between traditional and e-commerce customer purchase behavior model was found. Next, the re-search shows the main characteristics of shopping in B2C and provides a better understanding of the impact of digitaliza-tion. Research limitations – research will focus on the shopping in B2C e-commerce market in the Czech Republic, Lithuania and in the European Union. The data is based on the Czech Statistical Office, which covers a period from 2010 to 2018 and the respondents of the survey purchased online in the 12 months prior to 2018. Practical implications – the paper confirmed the fact that the B2C e-commerce market in the Czech Republic is developed and has potential to grow nationally and internationally. It is necessary to further investigate the relationship between cus-tomer purchase behavior, e-commerce, and other economic indicators, possibly including other factors. Originality/Value – the paper investigates online shopping for the period between 2010–2018. Finally, the authors dis-cuss the theoretical and practical implications of these results.

A significant part of the high pressure gas transport system of Gasunie cannot be examined by in-line inspection techniques. To ensure safe operation of these pipelines, an External Corrosion Direct Assessment (ECDA) module for PIMSLIDER (a pipeline integrity management system) is currently under development. The functional specifications of this module are based on NACE RP0502-2002, a recommended practice for ECDA. In addition to this, a new probabilistic methodology has been adopted, to take account for uncertainties associated with ECDA and to quantify the contributions from aboveground surveys and excavations to the integrity of a pipeline. This methodology, which is based on Structural Reliability Analysis (SRA) and Bayesian updating techniques, is presented in more detail in paper IPC2006-10092 of this conference. The DA module of PIMSLIDER enables computerized storage, retrieval and processing of all appropriate pipeline data and therefore guarantees highly accurate, reproducible and time saving integrity analyses of the Gasunie grid. Another important function of this system is the ability to use the complete database of all pipelines to pre-assess the integrity of a particular pipeline. This automated retrieval of data from pipelines with similar characteristics and/or environmental conditions results in a substantial increase of accessible data and enables Gasunie to improve the reliability of applied statistics throughout the process. As a consequence, the overall cost of inspections and excavations can be greatly reduced. In the Pre-Assessment phase, the DA module assists the integrity manager in gathering and analyzing data necessary to determine the current condition of a pipeline. After collection and visualization of the available data, the user can identify suitable ECDA regions. Furthermore, the gathered data are used to construct prior distributions of parameters relevant to the SRA model, such as the number and size of corrosion defects and pipeline-related parameters. In the Indirect Inspections step, the DA module allows the user to store and analyze the data from aboveground surveys, in order to identify and define the severity of coating faults and areas at which corrosion activity may occur. The probabilistic methodology accounts for the individual performance of each applied survey technique in terms of missed defects and false indications, in general a major source of uncertainty in ECDA. In the Direct Examinations phase, excavations are carried out to collect data to assess possible corrosion activity. Subsequently, the ECDA module uses this information to update, among other things, the parameters concerning the performance of survey techniques, the number of defects and the corrosion rate. As a result, updated failure frequencies are calculated for each ECDA-region (after each excavation if required), which are then used by the DA module to advise the integrity manager if additional mitigating activities are necessary, or by defining a reassessment interval.