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Analyses of the interactions among quality requirements (QRs) have often found that optimizing on one QR will cause serious problems with other QRs. As just one relevant example, one large project had an Integrated Product Team optimize the system for Security. In doing so, it reduced its vulnerability profile by having a single-agent key distribution system and a single copy of the data base – only...
This paper is a strong critic to the classical procedure used for the prediction of failure occurrences for mechanical and electronic equipment. The present procedure is based on the concept of randomness that has the undoubted vantage of the easiness, moreover, it is traditionally used so it is well known by scientists, technicians and experts in the field, but it a priori renounces to the knowledge...
The purpose of this article is to formulate a maintenance strategy for three parallel machines in a mechanical manufacture. The research method was the quantitative modeling, based on analytical models. Time between failures (TBF) and time-to-repair (TTR) data since April 2014 to September 2015 were modelled for the three machines. Weibull distribution fitted all the TBF data. Lognormal distribution...
Processes constrain developer freedom and impact software development cost. They can increase costs from only a few cents to almost 1000 USD per line of code. But they can also benefit the maintainability, dependability and safety of critical software. If failure risk costs are high, then the application of more expensive processes can actually reduce costs. Therefore it is important to understand...
More and more fantastic buildings with sculptural, challenging constructions are promoted, and they probably have owned or to be connected with very large spaces and highly need the remote control / monitoring / aid on devices, people and vehicles. To enhance detection availability, information integrity, or to rationally develop civilization services, counter sabotage attacks and radio interference,...
The High voltage static converter systems are deployed at different military and DoD assets in which power electronics is used for the isolated and stabilized AC or DC voltage/frequency conversion process and the Insulated Gate Bipolar Transistor (IGBT) triggering system plays crucial role in such systems. Such type of systems and equipments are being operated by the combat deployed personnel and...
Software architecture has become an increasingly important research topic in recent years. Concurrently much more attention has been paid to methods of evaluating non functional attributes of these architectures. However, in current architectural description languages (ADLs) based on a formal and abstract model of system behavior, there is a notable lack of support for representing and reasoning about...
Evaluation of dependability of electric supply is left to the skill and expertise of single engineers. Power systems schematics of health care facilities, airports, stadia, skyscrapers, main roads tunnels, too frequently, are not designed on the basis of concepts available in industrial context, since the ′60thies. The author has found strong resistance in the acceptance of developed design criteria,...
The topic of Reliability, Availability, and Maintainability (RAM) is a dedicated section in the new Ground Systems Engineering Handbook being prepared at The Aerospace Corporation. This paper provides an overview of the RAM content of the handbook, which focuses on the RAM tasks to be accomplished by ground systems over the program lifecycle. RAM involvement begins with program inception and continues...
The growing demand for electric power supply in developing countries has driven system operators to seek for better ways to harness more sources of sustainable power. The growth of power Networks and the number of elements which constitutes them has tremendously increased. This has created the need for an increased capacity and diligence in the sustenance of power systems in such countries. The adoption...
Three models have been suggested for analysis of reliability of a complex repairable system, namely helicopter operating unit using Weibull distribution. The first model utilizes failure data for assessing reliability of the unit. The second model, in addition to the use of failure data, includes eight input variables and one composite system output for its analysis. The third model adds another parameter...
R&M is extremely critical to build safe, reliable, and cost effective systems. The challenges of today's unmanned and ma nned space flight programs demand the most efficient use of our technical knowledge base to develop cost effective and affordable systems. An efficient reliability and maintainability program is essential to meet the challenges for the nation's Space Program. This paper discusses...
The industrial process in the area of on-board computers is characterized by small production series of onboard computers (hardware and software) configuration items with little recurrence at unit or set level (e.g. computer equipment unit, set of interconnected redundant units). These small production series result into a reduced amount of statistical data related to dependability, which influence...
Availability of Ships can wholly delegate the specialty of reliability, maintainability and supportability. The parameters of RMS of ships usually submit to logarithmic normal distribution elaborated in the paper. A Quasi Monte Carlo method and it's program of computation are proposed introducing the Halton sequence instead of the pseudorandom numbers of traditional Monte Carlo method to compute the...
Many types of implantable medical devices provide life-sustaining therapy for patients and are, therefore, designed for high levels of reliability. New concepts and approaches in prognostics and health management of systems may enable improved opportunities for ensuring continuity of life-sustaining therapies by providing adequate response time to handle emerging issues prior to adverse clinical impacts...
The probability of correct operation of the system during a given lifetime is called the reliability. The reliability of a complete satellite communications system depends on the reliability of its two principal constituents — the satellite and the ground stations. The availability of a complete satellite communications system depends not only on the reliability of the constituents of the system but...
This paper discusses a Reliability, Availability, and Maintainability (RAM) independent assessment conducted to support the refurbishment of the Compressor Station at the NASA Langley Research Center (LaRC). The paper discusses the methodologies used by the assessment team to derive the repair by replacement (RR) strategies to improve the reliability and availability of the Compressor Station (Ref...
The Department of Defense (DoD) has put an increased focus on reliability during system acquisition and development. This is due to historically poor reliability performance which has significantly increased sustainment costs for systems that have been built over the last 25 years. The Director of the Department of Operational Test and Evaluation has written a memorandum, dated June 30, 2010 with...
The paper defines the Design Interface process by which system design characteristics of Reliability and Maintainability are analyzed and trade studies conducted to influence the design to meet operational and sustainment requirements. Given that the total cost of Reliability may account for as much as 60% of a system's life Cycle Cost [1], emphasis on reducing the impact of Reliability related cost...
In this paper we discuss the way to identify various design patterns, their types and about the methods involved in the re-designing process. We also propose to evaluate the identified patterns considering various quality attributes (e.g, maintainability, security, availability, reliability) beside the quantitative character. Our proposal is to identify the design patterns with respect to the internet...
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