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N-version Programming
''N''-version programming (NVP), also known as multiversion programming or multiple-version dissimilar software, is a method or process in software engineering where multiple functionally equivalent programs are independently generated from the same initial specifications.N-Version Programming: A Fault-Tolerance Approach to Reliability of Software Operation Liming Chen; Avizienis, A., Fault-Tolerant Computing, 1995, ' Highlights from Twenty-Five Years'., Twenty-Fifth International Symposium on, Vol., Iss., 27-30 Jun 1995, Pages:113- The concept of ''N''-version programming was introduced in 1977 by Liming Chen and Algirdas Avizienis with the central conjecture that the "independence of programming efforts will greatly reduce the probability of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Engineering
Software engineering is a branch of both computer science and engineering focused on designing, developing, testing, and maintaining Application software, software applications. It involves applying engineering design process, engineering principles and computer programming expertise to develop software systems that meet user needs. The terms ''programmer'' and ''coder'' overlap ''software engineer'', but they imply only the construction aspect of a typical software engineer workload. A software engineer applies a software development process, which involves defining, Implementation, implementing, Software testing, testing, Project management, managing, and Software maintenance, maintaining software systems, as well as developing the software development process itself. History Beginning in the 1960s, software engineering was recognized as a separate field of engineering. The development of software engineering was seen as a struggle. Problems included software that was over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fault Tolerance
Fault tolerance is the ability of a system to maintain proper operation despite failures or faults in one or more of its components. This capability is essential for high-availability, mission-critical, or even life-critical systems. Fault tolerance specifically refers to a system's capability to handle faults without any degradation or downtime. In the event of an error, end-users remain unaware of any issues. Conversely, a system that experiences errors with some interruption in service or graceful degradation of performance is termed 'resilient'. In resilience, the system adapts to the error, maintaining service but acknowledging a certain impact on performance. Typically, fault tolerance describes computer systems, ensuring the overall system remains functional despite hardware or software issues. Non-computing examples include structures that retain their integrity despite damage from fatigue, corrosion or impact. History The first known fault-tolerant computer was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redundancy (engineering)
In engineering and systems theory, redundancy is the intentional duplication of critical components or functions of a system with the goal of increasing reliability of the system, usually in the form of a backup or fail-safe, or to improve actual system performance, such as in the case of GNSS receivers, or multi-threaded computer processing. In many safety-critical systems, such as fly-by-wire and hydraulic systems in aircraft, some parts of the control system may be triplicated, which is formally termed triple modular redundancy (TMR). An error in one component may then be out-voted by the other two. In a triply redundant system, the system has three sub components, all three of which must fail before the system fails. Since each one rarely fails, and the sub components are designed to preclude common failure modes (which can then be modelled as independent failure), the probability of all three failing is calculated to be extraordinarily small; it is often outweighed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nancy Leveson
Leveson in 2022 Nancy G. Leveson is an American specialist in system and software safety and a professor of Aeronautics and Astronautics at Massachusetts Institute of Technology (MIT), United States. Leveson gained her degrees (in computer science, mathematics and management) from University of California, Los Angeles, including her PhD in 1980. Previously she worked at University of California, Irvine, and the University of Washington as a faculty member. She has studied safety-critical systems such as the Traffic Collision Avoidance System (TCAS) for the avoidance of midair collisions between aircraft and problems with the Therac-25 radiation therapy machine. Leveson has been editor of the journal '' IEEE Transactions on Software Engineering''. She has held memberships in the ACM, IEEE Computer Society, System Safety Society, and AIAA. Biography Leveson is Professor of Aeronautics and Astronautics and also Professor of Engineering Systems at MIT. Prof. Leveson conducts re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronic Voting
Electronic voting is voting that uses electronic means to either aid or handle casting and counting ballots including voting time. Depending on the particular implementation, e-voting may use standalone '' electronic voting machines'' (also called EVM) or computers connected to the Internet (online voting). It may encompass a range of Internet services, from basic transmission of tabulated results to full-function online voting through common connectable household devices. The degree of automation may be limited to marking a paper ballot, or may be a comprehensive system of vote input, vote recording, data encryption and transmission to servers, and consolidation and tabulation of election results. A worthy e-voting system must perform most of these tasks while complying with a set of standards established by regulatory bodies, and must also be capable to deal successfully with strong requirements associated with security, accuracy, speed, privacy, auditability, accessib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zero-day Exploit
A zero-day (also known as a 0-day) is a vulnerability or security hole in a computer system unknown to its developers or anyone capable of mitigating it. Until the vulnerability is remedied, threat actors can exploit it in a zero-day exploit, or zero-day attack. The term "zero-day" originally referred to the number of days since a new piece of software was released to the public, so "zero-day software" was obtained by hacking into a developer's computer before release. Eventually the term was applied to the vulnerabilities that allowed this hacking, and to the number of days that the vendor has had to fix them. Vendors who discover the vulnerability may create patches or advise workarounds to mitigate it – though users need to deploy that mitigation to eliminate the vulnerability in their systems. Zero-day attacks are severe threats. Definition Despite developers' goal of delivering a product that works entirely as intended, virtually all software and hardware contain bugs. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triple Modular Redundancy
In computing, triple modular redundancy, sometimes called triple-mode redundancy, (TMR) is a fault-tolerant form of N-modular redundancy, in which three systems perform a process and that result is processed by a majority-voting system to produce a single output. If any one of the three systems fails, the other two systems can correct and mask the fault. The TMR concept can be applied to many forms of Redundancy (engineering), redundancy, such as software redundancy in the form of N-version programming, and is commonly found in fault-tolerant computer systems. Space satellite systems often use TMR, although satellite RAM usually uses Hamming(7,4), Hamming error correction. Some ECC memory uses triple modular redundancy hardware (rather than the more common Hamming code), because triple modular redundancy hardware is faster than Hamming error correction hardware. Called repetition code, some communication systems use N-modular redundancy as a simple form of forward error correct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Redundancy
In computer main memory, auxiliary storage and computer buses, data redundancy is the existence of data that is additional to the actual data and permits correction of errors in stored or transmitted data. The additional data can simply be a complete copy of the actual data (a type of repetition code), or only select pieces of data that allow detection of errors and reconstruction of lost or damaged data up to a certain level. For example, by including computed check bits, ECC memory is capable of detecting and correcting single-bit errors within each memory word, while RAID 1 combines two hard disk drives (HDDs) into a logical storage unit that allows stored data to survive a complete failure of one drive. Data redundancy can also be used as a measure against silent data corruption; for example, file systems such as Btrfs and ZFS use data and metadata checksumming in combination with copies of stored data to detect silent data corruption and repair its effects. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fault Tolerant Design
Fault tolerance is the ability of a system to maintain proper operation despite failures or faults in one or more of its components. This capability is essential for high-availability, mission-critical, or even life-critical systems. Fault tolerance specifically refers to a system's capability to handle faults without any degradation or downtime. In the event of an error, end-users remain unaware of any issues. Conversely, a system that experiences errors with some interruption in service or graceful degradation of performance is termed 'resilient'. In resilience, the system adapts to the error, maintaining service but acknowledging a certain impact on performance. Typically, fault tolerance describes computer systems, ensuring the overall system remains functional despite hardware or software issues. Non-computing examples include structures that retain their integrity despite damage from fatigue, corrosion or impact. History The first known fault-tolerant computer was SAP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reliability Engineering
Reliability engineering is a sub-discipline of systems engineering that emphasizes the ability of equipment to function without failure. Reliability is defined as the probability that a product, system, or service will perform its intended function adequately for a specified period of time, OR will operate in a defined environment without failure. Reliability is closely related to availability, which is typically described as the ability of a component or system to function at a specified moment or interval of time. The ''reliability function'' is theoretically defined as the probability of success. In practice, it is calculated using different techniques, and its value ranges between 0 and 1, where 0 indicates no probability of success while 1 indicates definite success. This probability is estimated from detailed (physics of failure) analysis, previous data sets, or through reliability testing and reliability modeling. Availability, testability, maintainability, and maintenance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Safety Engineering
Safety engineering is an engineering Branches of science, discipline which assures that engineered systems provide acceptable levels of safety. It is strongly related to industrial engineering/systems engineering, and the subset system safety engineering. Safety engineering assures that a life-critical system behaves as needed, even when components Failure, fail. Analysis techniques Analysis techniques can be split into two categories: Qualitative research, qualitative and Quantitative research, quantitative methods. Both approaches share the goal of finding causal dependencies between a hazard on system level and failures of individual components. Qualitative approaches focus on the question "What must go wrong, such that a system hazard may occur?", while quantitative methods aim at providing estimations about probabilities, rates and/or severity of consequences. The complexity of the technical systems such as Improvements of Design and Materials, Planned Inspections, Fool-pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Quality
In the context of software engineering, software quality refers to two related but distinct notions: * Software's functional quality reflects how well it complies with or conforms to a given design, based on functional requirements or specifications. That attribute can also be described as the fitness for the purpose of a piece of software or how it compares to competitors in the marketplace as a worthwhile product. It is the degree to which the correct software was produced. * Software structural quality refers to how it meets non-functional requirements that support the delivery of the functional requirements, such as robustness or maintainability. It has a lot more to do with the degree to which the software works as needed. Many aspects of structural quality can be evaluated only statically through the analysis of the software's inner structure, its source code (see Software metrics), at the unit level, and at the system level (sometimes referred to as end-to-end testin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
