Darrell G. Linton
University of Central Florida
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Featured researches published by Darrell G. Linton.
IEEE Transactions on Reliability | 1974
Darrell G. Linton; John G. Saw
A class of repairable systems known as k-out-of-n:F systems, 1 ? k ? n, consists of n units in parallel redundancy which are serviced by a single repairman; system failure occurs when k units are simultaneously inoperable for the first time. In this paper, assuming constant failure rates and general repair distributions, reliability characteristics of the k-out-of-n:F system are treated using two different methods. In Part I, a conditional transform approach is applied to the 2-out-of-n:F system. Transforms of distributions are obtained for T (the time to system failure), the time spent on repairs during (0, T) and the free time of the repairman during (0, T). In Part II, the supplementary variable technique is used to investigate time to failure characteristics of the k-out-of-n:F system for k = 2 and k = 3. A model of an airport limousine service illustrates the use of the results.
IEEE Transactions on Reliability | 1989
Darrell G. Linton
The author examines a class of 1-out-of-n:G systems consisting of n nominally identical units in parallel redundancy serviced by a single repair facility. Assuming constant failure rates and general repair distributions permits the problem of finding the Laplace transform of the time-to-system-failure distribution and the mean time-to-system-failure to be reduced to solving a closed-form system of (n-1) by (n-1) linear equations, for n at least 4. Numerical results are presented using a model of a satellite maintenance service. >
Information & Software Technology | 1994
Soheil Khajenoori; Darrell G. Linton; Carl A Morris
Abstract A method for enhancing software reusability (and hence increasing productivity) when developing a new software system, is to reuse design components from an existing system. In this paper, it is shown that techniques associated with the essential modelling approach to system development are effective tools for determining reusable components during the software development process and, hence, the employment of reusable components may be more productive than incorporating reusable code alone. These conclusions are illustrated with an example involving the development of a colour printer device driver on a UNIX-based Sun platform and a colour scanner device driver on a VMS-based DEC platform.
IEEE Transactions on Reliability | 1981
Darrell G. Linton
A 2-out-of-n:F system with exponential failure and Erlang repair times is considered; the probability density function for the time-to-system-failure (T) is exhibited and the probability generating function for the number of degradations (i.e., subsystem failures which are not essential to system operation) occurring during (0, T) is derived. Numerical results are also presented.
IEEE Transactions on Reliability | 1973
Darrell G. Linton; Robert N. Braswell
A conditional transform approach is applied to the two-unit standby redundant system with instantaneous switchover, and with failure and repair times that follow general well-behaved distributions for each unit. Transforms of distributions are obtained for T, the time to system failure, the number of repairs completed during T, the time spent on repair during T, and the idle time of the repairman during T. Applicable numerical methods are also discussed.
IEEE Transactions on Reliability | 1995
Darrell G. Linton; Soheil Khajenoori; Gil Hebert; J.V. Bullington
This paper uses an expression for system reliability at a repair depot to construct a nonlinear, nonpolynomial function which is amenable to numerical analysis and has a zero equal to the supportability turnaround time (STAT) for a failed unit. System reliability is in terms of the constant failure rate for all units, number of spares on-hand at the time a unit fails, and projected repair completion dates for up to four unrepaired units. In this context, STAT represents the longest repair time (for a failed unit) which assures a given reliability level; system reliability is the probability that spares are ready to replace failed units during the STAT period. The ability to calculate STAT-values is important for two reasons: (1) subtraction of the repair time for a failed unit from its STAT-value yields the latest repair start-time (for this unit) which assures a desired reliability, and (2) the earlier the latest repair start-time, the higher the priority for starting the repair of this unit. Theorems show the location of STAT with respect to the list of repair completion dates, and form the foundation of the root-finding-based algorithm for computing STAT-values. Numerical examples illustrate the algorithm.
IEEE Transactions on Reliability | 1997
Darrell G. Linton; Soheil Khajenoori; K. Halder
Linton et al. (1995) use an expression for the reliability of the system for repairing failed units (FU) at a repair depot to compute the longest repair time for a newly failed unit (NFU) which assures a given reliability level (also termed the NFU supportability turnaround time or STAT) in terms of the constant failure rate for all components, the number of spares on-hand, and projected downstream repair completion times for FU. Since subtraction of the repair time for a NFU from its STAT-value yields the NFUs latest repair start-time (RST) which assures a given repair-depot system reliability (RD-SR), STAT-values are important for scheduling RST. If a NFUs latest RST is negative, however, the NFU cannot be repaired and returned to the status of a spare in time to assure the desired RD-SR level. When a NFUs latest RST is negative and some previously FU have not yet begun their repair, then Sched-Alg (the algorithm in this paper)-(i) shows whether or not it is possible to reschedule RST for FU so that the latest RST for the NFU is nonnegative (and, hence, the desired RD-SR can be maintained) and, if a reassignment of RST to meet RD-SR is possible; and (ii) determines a new RST schedule for FU which ensures the desired RD-SR, minimizes the number of adjustments required, and reduces the total adjustment time. Numerical examples illustrate Sched-Alg.
annual simulation symposium | 1992
Darrell G. Linton; Soheil Khajenoori; J. V. Bullington; H. Cat; K. Halder; G. Herbert; S. Sinnappan; Mark D. Heileman
STARSIM (Space Transportation Activities and Resources SIMulation) is an object-oriented, menu-driven, user-friendly, decision support system for simulating and managing Space-Shuttle ground processing activities. The purpose of STARSIM is to permit trade-off studies to be performed for any set of input parameters (e.g., determining the effects on launches per year of adding a bay in the orbiter processing facility). Output is displayed both numerically (for global statistical information, including life-cycle cost estimates) and in Gantt chart form (for visualizing when and where each orbiter vehicle experiences waiting, processing, blocking and maintenance periods, as well as the reasons for blocking).<<ETX>>
IEEE Transactions on Reliability | 1996
Darrell G. Linton; Soheil Khajenoori; Y. Yi; Gil Hebert
The repair-depot (where failed items are replaced with spares and scheduled for repair) system-reliability (RDSR) is the probability that spares are immediately available to replace failed units during the time period of interest, and it is calculated in terms of the constant failure rate for parts under consideration, the number of spare units on-hand (s), and projected repair completion dates for (n-1) units in the repair process, n/spl ges/2. Linton et al. (1995) show an expression for RDSR in terms of n nested sums, where the upper limit of each sum is a function of s. This paper derives a restructured expression (LKYH algorithm) for computing RDSR, and shows that the nested-sum form for RDSR uses O(s/sup n/) mathematical operations, while LKYH requires only O(s) mathematical operations. Numerical examples illustrate the increase in efficiency of LKYH; e.g., when n=s=10, the execution time for computing RDSR on a 486/66-computer is reduced from 198 seconds for the multiple-sum form to less than 1 second for LKYH.
Simulation | 1994
Darrell G. Linton; Soheil Khajenoori; Mark D. Heileman; J. Van Bullington; Huy Cat; Kallol Halder; Gil Hebert; Sundar Sinnappan
In order to verify, validate and graphically display results for simulation models, an analysis module (separate from the simulation itself) called Reporter Object (RO) was developed. RO receives log files (in a particular format) from any simulation model and produces (a) Gantt-type charts, showing all waiting, processing, and blocking times (including reasons for the blocking) for all desired objects (or entities) at all processing facility locations at all times of interest, and (b) pie charts depicting the percen tages represen ted by subcategories associated with a main category (e.g., the percentages of direct material, direct labor and indirect fixed costs associated with total cost). RO was designed to be either integrated with an object-oriented simulation engine or executed as a separate program for use with any simulation model. In order to illustrate its capabilities, Reporter Object is used in conjunction with STARSIM (an acronym for Space Transportation Activities and Resources SIMulation), an object- oriented, menu-driven, simulation model of Space-Shuttleground processing activities, to show ROs architectural relationship to the simulation engine, the format of required log files (and potential extensions), the types of output that may be produced and the ramifications of this output.