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1.
Intheprojectmanagement,theschedulingproblemforshorteningthedurationundertheconstraintofre sourcesiscalledresourceconstrainedprojectschedulingproblem (RCPSP) [1] .Withtheincreasingcompetitionwithinglobalmarket ,thereisanurgentneedforenter priseintegration .Asanexample ,modernbusinessesnolongercompeteasindividualcompaniesbutratherassup plychains .Thus ,thesuccessofasinglecompanyde pendsonitsabilitytomanageandintegratenetworksofvariousbusinessrelationshipsinwhichcertainactivitiesarelinkedtoothe… 相似文献
2.
In the present study, we investigated the degree to which responding would resurge in children diagnosed with Autism Spectrum
Disorders (ASD) following an intervening training period comprising different schedules of reinforcement. Twenty-four children
of the ages 7–15, with a diagnosis of an ASD, were taught a play a sequence on a variable ratio- (VR) 3 schedule of reinforcement,
during a 30-min session. The play sequence was then extinguished before the participants were taught a second play sequence,
using a VR-4 schedule for 30 min, a VR-4 schedule for 60 min, or a VR-2 schedule for 30 min. A 5-min extinction session was
then conducted to determine the impact that the intervening schedules had on the resurgence of the original behavior. The
original sequence resurged to a greater extent for Group VR-4 30 min than it did for the other two groups. The results provide
evidence that the length of time between initial training and testing is not a prime determinant of the level of resurgence,
but that the amount of conditioning may play a stronger role: The greater the number of reinforcers received, the smaller
the resurgence effect. 相似文献
3.
To minimize the deviations of the net present values of project payment for both the owner and the client and optimize project payment schedules, a Nash equilibrium model based on game theory was set up and a genetic algorithm was developed to work out the Nash equilibrium solution with a two-stage backward inductive approach that requires the client responds to the owner’s payment schedule with an activity schedule so as to maximize the client’s net present value of cash flows. A case study demonstrated that a payment schedule at the Nash equilibrium position enables both the owner and the client to gain their desirable interests, thus is a win-win solution for both parties. Despite the computation time of the proposed algrithm in need of improving, combining Nash equilibrium and genetic algorithm into a complete-information dynamic-game model is a promising method for project management optimization. 相似文献
4.
Phil Reed 《Learning & behavior》2016,44(1):78-84
An experiment examined the impact of a procedure designed to prevent response or extinction strain occurring on random interval schedules with a linear feedback loop (i.e., an RI+ schedule). Rats lever-pressed for food reinforcement on either a RI+ or a random interval (RI) schedule that was matched to the RI+ schedule in terms of reinforcement rate. Two groups of rats responded on an RI+ and two on an RI schedule matched for rate of reinforcement. One group on each schedule also received response-independent food if there had been no response for 60 s, and response-independent food continued to be delivered on an RT-60 schedule until a response was made. Rats on the RI and RI+ obtained similar rates of reinforcement and had similar reinforced inter-response times to one another. On the schedules without response-independent food, rats had similar rates of response to one another. However, while the delivery of response-independent food reduced rates of response on an RI schedule, they enhanced response rates on an RI+ schedule. These results suggest that rats can display sensitivity to the molar aspects of the free-operant contingency, when procedures are implemented to reduce the impact of factors such as extinction-strain. 相似文献
5.
Widely cited experiments on optimal foraging have used bivalued distributions as representing environmental stochasticity, characterizing these in terms of their arithmetic means. In contrast, research on free-operant choice has established that organisms prefer variable patterns of food delivery, relative to fixed patterns with the same mean values. To explore such departures from linear averaging, specifically with respect to bivalued alternatives, pigeons were given choices between a fixed-ratio (FR) schedule of food delivery that required 15, 30, or 60 responses and bivalued variable-ratio schedules with an arithmetic mean of 60,5 or 60, A bivalued schedule of 1 and 120 was preferred almost exclusively over each of the FR values. With a bivalued schedule of 15 and 105, there was a shift of preference, most notably in the FR-15 condition, but in no case was linear averaging a good predictor of the birds’ choices. Geometric averaging fared better, but even this failed to represent the apparent salience of the minimum value of the bivalued schedule in some conditions. 相似文献
6.
Pigeons were trained on a multiple schedule in which separate concurrent schedules were presented in the two components of the schedule. During one component, concurrent variable-interval 40-sec variableinterval 80-sec schedules operated. In the second component, concurrent variable-interval 40-sec variableinterval 20-sec schedules operated. After stable baseline performance was obtained in both components, extinction probe choice tests were presented to assess preference between the variable-interval 40-sec schedules from the two components. The variable-interval 40-sec schedule paired with the variableinterval 80-sec schedule was preferred over the variable-interval 40-sec schedule paired with the variableinterval 20-sec schedule. The subjects were also exposed to several resistance-to-change manipulations: (1) prefeeding prior to the experimental session, (2) a free-food schedule added to timeout periods separating components, and (3) extinction. The results indicated that preference and resistance to change do not necessarily covary. 相似文献
7.
W. Kirk Richardson 《Learning & behavior》1976,4(3):231-240
Keypecking of pigeons was studied under differential-reinforcement-of-low-rate (DRL) and variable-interval (VI) schedules in which the interreinforcement times on the two schedules were equated by a yoking procedure. Each schedule was available for half of every session and a change of schedule was signaled by a change of key color. The value of the DRL schedule was varied from .5 to 300 sec. Response rates were always higher in the VI schedule, but within sessions there was a sharp change in response rate coincident with the change in schedule only under lower schedule values. A group without prior training was tested with a 180-sec schedule value, and it, too, developed a higher response rate during the VI schedule, showing that the effect was not dependent on prior experience under low schedule values. In all conditions except the .5- and 1-sec values of the schedule, the mean proportion of responses emitted during the VI schedule was approximately .85 of the responses emitted during both schedules. The conclusion was that the requirement of a minimum interresponse time for reinforcement may work its effect by determining which responses may occur just prior to the reinforced response and thus receive delayed reinforcement. 相似文献
8.
专业人才培养方案的构建 总被引：42，自引：0，他引：42
本文论述了构建一个完整的专业培养方案应该具备的三个基本要素：一是要选择构建培养方案的主线，二是要根据不同的学科专业，选择课程体系的结构模式，三是选择适当的技术路线对教学计划进行具体的修订。 相似文献
9.
高校校园工程建设具有时间短、工期弹性小的特点,高校工程建设需要建立科学的基建管理模式,制定项目各阶段的工作计划,认真做好项目实施的准备工作,优选施工队伍,合理控制设计阶段及施工阶段的进度. 相似文献
10.
In the first condition in Experiment 1, 6 rats were exposed to concurrent variable ratio (VR) 30, variable interval (VI) 30-sec
schedules. In the next two conditions, the subjects were exposed to concurrent VI VI schedules and concurrent tandem VI-differential-reinforcement-of-high-rate
VI schedules. For the latter conditions, the overall and relative reinforcer rates equaled those in the first condition. Only
minor differences appeared in time allocation (a molar measure) across conditions. However, local response rate differences
(a molecular measure) appeared between schedule types consistently with the interresponse times these schedules reinforced.
In Experiment 2, these findings reappeared when the prior experiment was replicated with 5 subjects, except that the VR schedule
was replaced by a VI plus linear feedback schedule. These results suggest that within the context tested, the molar factor
of relative reinforcement rate controls preference, whereas the molecular factor of the relation between interresponse times
and reinforcer probability controls the local response rate. 相似文献
11.
Sated rats, previously trained to leverpress for H2O reinforcement on continuous or variable-interval (10-sec or 60-sec) schedules, were given NaCl injections and tested for leverpressing. Under all schedules, responding was an inverted U function of NaCl concentration (0.15M to 3.0M). However, NaCl thirst produced relatively little change in behavior under the VI 60-sec schedule. 相似文献
12.
Three pigeons pecked keys for food reinforcers delivered by multiple variable interval variable interval schedules in the first part of each session (baseline) and by multiple variable interval extinction schedules in the second part of each session (contrast). The variable interval schedules delivered reinforcers after an average of 4 min or 30 sec in different conditions. The duration of a time-out between the components varied in five steps from 5 to 120 sec. Positive contrast occurred for all time-out durations in both experiments. That is, the rate of responding emitted during the constant, variable interval component was greater during the contrast than during the baseline schedules. The size of contrast did not change systematically with changes in timeout duration. These results violate most theories of contrast. They are compatible with the idea that animals integrate reinforcers over intervals longer than 2 min. 相似文献
13.
14.
The effects of different schedule requirements at reinforcement on patterns of responding by pigeons were assessed under conjunctive schedules with comparable response-number requirements, Under one conjunctive schedule (conjunctive fixed-interval fixed-ratio schedule), a response was reinforced after a 6-min interval had elapsedand a specific minimum number of responses had been emitted, Under a second conjunctive schedule, a response was reinforced after the 6-min fixed interval and upon completion of a tandem schedule requirement (conjunctive fixed-interval tandem schedule), This schedule retained the same required minimum number of responses as the first conjunctive schedule, but responses were never reinforced according to a fixed-ratio schedule; the tandem schedule was comprised of a fixed-ratio and a small (.1 to 10.0 sec) fixed-interval schedule, Under the conjunctive fixed-interval fixed-ratio schedule, responding was characterized by an initial pause, an abrupt transition to a high response rate, and a second transition to a lower rate that prevailed or slightly increased up to reinforcement, Under the conjunctive fixed-interval tandem schedule, pauses were extended, response rates were lower, and the initial high rate of responding was generally absent, The above effects depended upon the size of the fixed interval of the tandem schedule, The distinct pattern of responding generated by conjunctive fixed-interval fixed-ratio schedules depends upon occasional reinforcement of fixed-ratio responding and not merely on the addition of a minimum number of required responses. 相似文献
15.
Masanori Kono 《Learning & behavior》2013,41(4):425-432
In optimal foraging theory (OFT), energy expenditure is an important variable for predicting foraging behavior. However, early studies, including operant simulations of foraging, did not measure energy expenditure. In the present study, an adjusting energy (AE) schedule was developed to control energy expenditure. Interresponse energy (IRE), a measure of the energy expenditure during a response, was calculated by dividing the square of the elapsed time between two consecutive responses by the square of the straight-line distance between the locations of the same two responses. An adjusting procedure was employed to estimate the indifference point between the requirements of the AE schedule and a fixed ratio (FR) schedule, which has been used in many operant simulations. In the adjusting procedure, pigeons adjusted the requirement of the AE schedule to that of the FR schedule. The results showed a systematic relationship between the requirements of the AE and FR schedules. Moreover, the total IRE per reinforcement systematically increased with the AE requirement. Thus, the present study demonstrates the utility of the AE schedule as a procedure for testing the validity of OFT. 相似文献
16.
Pigeons were trained on an operant procedure to discriminate between morning and afternoon when location did not vary (Experiment
1). The pigeons were placed on a fixed interval (FI) schedule in the morning and on a different FI schedule in the afternoon.
Probe trials that occurred at the beginning of the training sessions were examined. The pigeons responded differently, depending
on the time of day, reflecting the learning of a stable 24-h memory representation of the association between the FI schedules
and the time of day. The pigeons from Experiment 1 were then clock shifted and tested twice, to determine whether they were
relying on an endogenous circadian oscillator, an hourglass mechanism influenced by the photoperiod, or environmental noise
to make the time-of-day discrimination (Experiment 2). The results of the second experiment indicated a circadian mechanism
was most important for the observed time-of-day learning. 相似文献
17.
Pigeons’ preference between fixed-interval and variable-interval schedules was examined using a concurrent-chains procedure. Responses to two concurrently available keys in the initial links of the concurrent chains occasionally produced terminal links where further responses were reinforced under either a fixed- or variable-interval schedule. In previous studies, preferences for the variable schedule with such a procedure have been interpreted as reflecting atemporal scaling process that heavily weights the shorter intervals in the variable schedule. The present experiment examined whetherpredictability, i.e., the presence of external stimuli correlated with the reinforcement interval, might also influence preference in such situations. When the two intervals in a variable schedule were made predictable by being associated with different key colors, preference for that schedule increased. This increase was reliable but small in magnitude and transient when initial-link responses only occasionally produced terminal links; it was large in magnitude when only one response in the initial link was required to produce the appropriate terminal-link schedule. The results suggest that preference between fixed and variable schedules may be influenced both by temporal scaling and to a lesser extent by predictability of the reinforcement intervals. 相似文献
18.
Experiment 1 investigated the behavior of rats trained to leverpress on a concurrent variable ratio (VR) 30 VR-30 schedule with a brief, 500-msec, light occurring at the midpoint of the ratio on one of the levers. Higher response rates were recorded on the lever associated with this stimulus, a finding that paralleled the effect produced by inserting primary reinforcement at the midpoint (i.e., by training on a concurrent VR-30 VR-15 schedule). Similar results were found in Experiment 2 using a concurrent VR-20 VR-20 schedule with a 2-sec visual stimulus presented midway through one of the components. In addition, a brief stimulus inserted midway through the VR-20 component of a concurrent VR-20 VR-10 schedule retarded the development of a difference in response rates between the components relative to a VR-20 VR-10 group lacking the signal. In Experiment 3, multiple VR VR schedules were used. Again, the response rate was higher in the component that had the added stimulus or, for a second group of subjects, on the component with the smaller response requirement. Probe-choice trials revealed a preference for the component that generated the higher rate in both groups. Presenting a stimulus partway through a ratio appears to reduce the effect on response rate and choice of a large ratio value. 相似文献
19.
20.
In three experiments, we examined the effect on the patterns of responding noted on fixed interval (FI) schedules of prior
exposure to a range of interval and ratio schedules. Rats leverpressed for food reinforcement on random ratio (RR), random
interval (RI), or variable interval (VI) schedules prior to transfer to FI schedules. In Experiment 1, prior exposure to an
RR schedule retarded the development of typical FI patterns of responding. Exposure to a yoked RI schedule produced even greater
retardation of typical FI performance. This effect was replicated in Experiment 2, using a within-subjects design. Rats responded
on a multiple RR-RI schedule prior to a multiple FI-FI schedule. Typical FI performance emerged more slowly in the component
previously associated with the RI than with that associated with the RR. In Experiment 3, exposure to an RR schedule retarded
the development of FI performance to a greater extent than did exposure to a VR schedule. The latter schedule was programmed
to allow the possibility that inhibitory control would develop after reinforcement. These results confirm that ratio schedules
independently result in the disruption of FI responding. This effect was not long lasting and cannot be used plausibly to
explain species differences in responding to FI schedules. However, it does suggest that temporal control—as manifested by
the transfer of inhibitory control from one schedule to another—could facilitate movement between interval schedules. 相似文献