Fixed interval schedule

DeWeese, J. Schedule-induced biting under fixed-interval schedules of food or electric-shock presentation. J Exp Anal Behav 27 419-431, 1977. 

Cory-Slechta DA, O Mara DJ, Brockel BJ. 1998. Nucleus accumbens dopaminergic mediation of fixed interval schedule-controlled behavior and its modulation by low-level lead exposure. J Pharmacol Exp Ther 286 794-805. 

Cory-Slechta DA, Pazmino R, Bare C. 1997a. The critical role of nucleus accumbens dopamine systems in the mediation of fixed interval schedule-controlled operant behavior. Brain Res 764 248-256. 

Balster RL Schuster CR (1973b) Fixed-interval schedule of cocaine reinforcement effect of dose and infusion duration. Exp Anal Behav 20 119-129. 

Fixed interval schedule reinforces the response that occurs after a fixed period of time elapses... 

Fixed interval schedule Increased response rates Cory-Slechta and Thompson, 1979... 

Temporally-spaced responding is a modified fixed interval schedule, more commonly known as differential reinforcement of low (or high) rate. In this... 

A series of behaviors suggesting deficient response inhibition is also seen following developmental Pb exposure. Specific behavioral deficits are seen on tests of passive avoidance, one way active avoidance, differentied reinforcement of low rates of responding (DHL-EO)" and fixed interval schedules of operant controlled behavior operant extinction and operant response inhibition, spontaneous cdternation," "" and various discrimination reversal problems " "" have also been observed following developmental Pb exposure. 

Figure 1 IRT absolute frequency distribution for one session of a fixed interval schedule for control (top) and monkeys exposed to 500/zg/kg per day of lead (bottom). The divisions along the abscissa represent classes of time between successive responses, in 100 ms increments. The lead-treated monkeys in general had a much higher absolute frequency of IRTs and a distribution skewed towards shorter IRTs...

Median IRT for Sessions 1-20 of a fixed-interval schedule for monkeys exposed 100 or 500 Ug/kg per day of lead from birth (randomization test, p = 0.05, 0.08, 0 versus three dose groups, respectively). Each symbol represents an individual... 

Andrews. J.S., and Holtzman, S.G. The interaction of ti-amphetamine and naloxone differs for rats trained on separate fixed-interval or fixed-ratio schedules of reinforcement. Pharmacol Biochem Behav 26 167-171, 1987. Angrist, B.M., and Gershon, S. Amphetamine abuse in New York City, 1966-1968. Semin Psychiatry 1 195-207, 1969. 

Monkey (Rhesus) 7-8 yr 1 x/d (C) 1.5 (altered performance on a fixed-interval-fixed-ratio schedule of reinforcement at age 7-8 years) Rice 1992 PbAc... 

At doses comparable to those that disrupt responding on FR schedules, LSD also causes less drastic suppression of the somewhat lower but nonetheless relatively high rates of responding maintained under certain fixed interval (FI) or variable interval (VI) schedules and generally increases behaviors that normally occur at low rates (5,7,44,48). 

Dietz DD, McMillan DE. 1979. Comparative effects of mirex and Kepone on schedule-controlled behavior in the rat I. Multiple fixed-ratio 12 fixed-interval 2 min schedule. Neurotoxicology 1 369-385. 

Only a few behavioral studies have so far been reported with these modulated RF fields. Chicks exposed to 450 MHz, 1 or 5 mW/cm2 fields sinusoidally modulated at 3 or 16 Hz during performance of a fixed-time 30 sec schedule of water reinforcement showed trends towards longer latency of response (44). In Soviet studies, rabbits and rats chronically exposed for 120 days to extremely low levels of 50 or 2500 MHz continuous fields or 10 GHz fields pulsed at 1000 or 20 Hz showed statistically significant alterations in conditioned reflexes with field intensities between 1.9 and 2.0 yW/cm2. A 2450 MHz, 1 mW/cm2 microwave field pulsed at 1000/sec had a synergic effect on the action of Valium (chlordiazepoxide) on fixed-interval behavior in rats (46). 

There are four simple schedules of reinforcement the fixed interval (FI) and the variable interval (VI), both of which are temporally based reinforcement schedules, and the fixed ratio (FR) and the variable ratio... 

Figure 9 Schematic cumulative records of performance on the fixed ratio (FR), variable ratio (VR), fixed interval (FI), and variable interval (VI) schedules of reinforcement. Responses are cumulated vertically over time. Each downward deflection of the pen represents reinforcement delivery horizontal lines indicate pausing. (Reproduced from Seiden LS and Dykstra LA (1977) Psychopharmacology A Biochemical and Behavioral Approach. New York, NY Van Nostrand Reinhold.)...

The order-promising process employed partitions the due date time horizon into three intervals fixed product, flexible product and flexible resource. For the fixed product interval, which spans from approximately the present time to two weeks into the future, resources, in the form of manufacturing orders (MO) are fixed. An MO specifies the production quantity for each product at each assembly line in each factory. That is, a fixed production schedule is set, which takes into account both production capacity availability and critical material availability. Having a fixed schedule stabilizes production dynamics in the near term and allows for the required materials to be set up and put in place. Any order commitments made for this time interval must fit within the fixed production schedule. In the flexible product interval, two kinds of resources, capacity and material, are considered. The capacity consists of both production capacity in different factories and transportation capacity from factories to sales subsidiaries. The production capacity is given daily at factory level in terms of machine-hour and manpower availability, while the transportation capacity is specified as weekly maximum quantity from factories to sales subsidiaries. The weekly availability of individual critical materials is aggregated into finished good level availability grouped based on the bill of material (BoM). Any order commitments made for this time interval must satisfy the capacity and material availability constraints. The flexible product interval spans from approximately two weeks to two months into the future. For the flexible resource interval, which covers due dates more than two months into the future, the only constraint considered is production capacity. This interval starts beyond the resource lead times so any resource commitments can be met. 

When most people think of preventive maintenance, they visualize scheduled, fixed interval maintenance that is done every day, every month, every quarter, every season, or at some other predetermined intervals. Timing may be based on days, or on intervals such as miles, gallons, activations, or hours of use. The use of performance intervals is itself a step toward basing preventive tasks on actual need, instead of just on a generality. 

Scheduling is primarily concerned with balancing demand and supply. Demand comes from the equipment s need for preventive maintenance. Supply is the availability of the equipment, craftspeople, and materials that are necessary to do the work. Establishing the demand is partially covered in the chapters on on-condition, condition monitoring, and fixed interval preventive maintenance tasks. Those techniques identify individual equipment as candidates for PM. 

That is, the warehouse does not decide the quantity of the order, but will receive a delivery as determined by the production schedule. Normally a fixed interval review model with a forecast demand for manufacturing planning is used in a push system. 

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