Availability Analysis

This paper presents a novel methodology, which allows a systematic availability analysis of satellite payload data processing systems implemented on SRAM-based FPGAs. The methodology allows (i) comparison of different Fault Detection, Isolation and Recovery (FDIR) schemes and (ii) prediction of the expected system availability in a particular radiation environment. Furthermore, it advances the state of the art by analysing embedded Block RAMs and employing a novel fault injection algorithm that enables more complex stochastic models. The applicability of the method is demonstrated by a case study representing a high availability payload data processing application. Since Block RAMs are also taken into account, the availability prediction precision is greatly increased. It is shown that the reliability prediction for two border cases, in which the Block RAMs are either ignored or assumed to be fully susceptible, can differ as much as 75%. With the proposed Block RAM profiling tool it is possible to determine a realistic reliability figure that is eventually required for the accurate estimation of the system availability.

I. INTRODUCTION Reliable functioning of embedded systems is of paramount concern to the billions of users that depend on these systems every day. Unfortunately most embedded systems still fall short of user's expectation of reliability. The incorporation of redundancy is one of the important techniques to improve the reliability and hence the effectiveness of the system. The system models with standby redundancies have been frequently analysed by various authors with different assumptions due to their vital existence in modern industries and business. Gupta, Tyagi and Kishan [6] discussed the concept of a two unit system with correlated failures and repairs and random appearance and disappearance of repairman. Kishan and Jain [8] analysed a two non-identical unit standby system model with repair, inspection and post-repair under classical and Bayesian viewpoints. Agnihotri and Satsangi [1] considered two unit identical systems with priority based repair and inspection. While Tuteja and Malik [9] discussed about reliability and profit analysis of two single unit models with three modes and different repair policies of repairman who appears and disappears randomly. Goel, Sharma and Gupta [2] worked on cost analysis of a system with intermittent repair and inspection under abnormal weather. Further Joorel, Kumar and Lal [3] put forth the concept of Reliability analysis of a complex system composed of two parallel subsystems without considering random appearance and disappearance of repairman in the system. Gupta, Goel and Tomer [7] provided the concept of analysis of a two unit standby system with correlated failure and repair and random appearance and disappearance of repairman. Nakagawa and Osaki [5] investigated stochastic behavior of two unit priority standby redundant system with repair. Recently Kakkar, Chitkara and Kumar [4] discussed reliability analysis of a cold standby system with repair equipment failure and appearance and disappearance of repairman with correlated lifetime. The purpose of the present paper is to put forth the concept of random appearance and disappearance of repairman in the system. The system comprises of two non-identical units A and B, each unit having two modes Normal and Failure in which unit A is operative and unit B is kept in standby mode. Upon failure of operative unit, unit B

The present paper deals with reliability analysis of a system comprises of a single unit. Initially system is in operative state with controlled demand factor i.e. when demand is less or equal to production then it may transit to the state with uncontrolled demand factor i.e. when demand is greater than production. The system remains in upstate with demand factor controlled and uncontrolled while in down state on failure of the unit. On failure of the system, an inspection is carried to detect the type of failure. There are three types of failures, i.e. failure due to poor design of component, improper selection of material and human error. Single repair facility is available to repair the system. The failure time distributions of the unit are taken as exponential and inspection time of the unit is also taken as exponential. The distribution of time to repair of unit is assumed to be general. The various important measures of system effectiveness have been obtained and studied.

This paper presents a novel methodology, which allows a systematic availability analysis of satellite payload data processing systems implemented on SRAM-based FPGAs. The methodology allows (i) comparison of different Fault Detection, Isolation and Recovery (FDIR) schemes and (ii) prediction of the expected system availability in a particular radiation environment. Furthermore, it advances the state of the art by analysing embedded Block RAMs and employing a novel fault injection algorithm that enables more complex stochastic models. The applicability of the method is demonstrated by a case study representing a high availability payload data processing application. Since Block RAMs are also taken into account, the availability prediction precision is greatly increased. It is shown that the reliability prediction for two border cases, in which the Block RAMs are either ignored or assumed to be fully susceptible, can differ as much as 75%. With the proposed Block RAM profiling tool it is possible to determine a realistic reliability figure that is eventually required for the accurate estimation of the system availability.

Single cell proteins (SCP) and oils (SCO) are promising alternatives for replacing conventional feed ingredients in animal and aquaculture fish feeds. The production costs of SCP and SCO need to be reduced by using inexpensive substrates (production by-products) suitable for cultivation of protein and oil producing microorganisms. This article reviews the availability of milk processing by-product – whey in Latvia, in 2019. Additionally, a simple production plant location optimization model is proposed, where no prior knowledge of location optimization or experience with dedicated software is required from the user. The case study demonstrated that the model is valid, and it can be used as a simple tool for resource acquisition from multiple sources to single production plant.

I. INTRODUCTION Reliable functioning of embedded systems is of paramount concern to the billions of users that depend on these systems every day. Unfortunately most embedded systems still fall short of user's expectation of reliability. The incorporation of redundancy is one of the important techniques to improve the reliability and hence the effectiveness of the system. The system models with standby redundancies have been frequently analysed by various authors with different assumptions due to their vital existence in modern industries and business. Gupta, Tyagi and Kishan [6] discussed the concept of a two unit system with correlated failures and repairs and random appearance and disappearance of repairman. Kishan and Jain [8] analysed a two non-identical unit standby system model with repair, inspection and post-repair under classical and Bayesian viewpoints. Agnihotri and Satsangi [1] considered two unit identical systems with priority based repair and inspection. While Tuteja and Malik [9] discussed about reliability and profit analysis of two single unit models with three modes and different repair policies of repairman who appears and disappears randomly. Goel, Sharma and Gupta [2] worked on cost analysis of a system with intermittent repair and inspection under abnormal weather. Further Joorel, Kumar and Lal [3] put forth the concept of Reliability analysis of a complex system composed of two parallel subsystems without considering random appearance and disappearance of repairman in the system. Gupta, Goel and Tomer [7] provided the concept of analysis of a two unit standby system with correlated failure and repair and random appearance and disappearance of repairman. Nakagawa and Osaki [5] investigated stochastic behavior of two unit priority standby redundant system with repair. Recently Kakkar, Chitkara and Kumar [4] discussed reliability analysis of a cold standby system with repair equipment failure and appearance and disappearance of repairman with correlated lifetime. The purpose of the present paper is to put forth the concept of random appearance and disappearance of repairman in the system. The system comprises of two non-identical units A and B, each unit having two modes Normal and Failure in which unit A is operative and unit B is kept in standby mode. Upon failure of operative unit, unit B

The present paper deals with reliability analysis of a system comprises of a single unit. Initially system is in operative state with controlled demand factor i.e. when demand is less or equal to production then it may transit to the state with uncontrolled demand factor i.e. when demand is greater than production. The system remains in upstate with demand factor controlled and uncontrolled while in down state on failure of the unit. On failure of the system, an inspection is carried to detect the type of failure. There are three types of failures, i.e. failure due to poor design of component, improper selection of material and human error. Single repair facility is available to repair the system. The failure time distributions of the unit are taken as exponential and inspection time of the unit is also taken as exponential. The distribution of time to repair of unit is assumed to be general. The various important measures of system effectiveness have been obtained and studied.

This paper presents a novel methodology, which allows a systematic availability analysis of satellite payload data processing systems implemented on SRAM-based FPGAs. The methodology allows (i) comparison of different Fault Detection, Isolation and Recovery (FDIR) schemes and (ii) prediction of the expected system availability in a particular radiation environment. Furthermore, it advances the state of the art by analysing embedded Block RAMs and employing a novel fault injection algorithm that enables more complex stochastic models. The applicability of the method is demonstrated by a case study representing a high availability payload data processing application. Since Block RAMs are also taken into account, the availability prediction precision is greatly increased. It is shown that the reliability prediction for two border cases, in which the Block RAMs are either ignored or assumed to be fully susceptible, can differ as much as 75%. With the proposed Block RAM profiling tool it is possible to determine a realistic reliability figure that is eventually required for the accurate estimation of the system availability.

This paper presents the analysis of a two-unit cold standby system with inspection time. There are two repairmen i.e. expert and assistant repairman. The failure and repair times of each unit have been assumed to be correlated and their joint density has taken as a bivariate exponential. Using the regenerative point technique, various reliability characteristics of interest have been obtained. The behavior of MSTF has been also studied graphically.