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Green scheduling is an important means to achieve sustainable industrial development and enhance the green efficiency of enterprises. Given the characteristics of a modern crude oil supply system, the shuttle tanker fleet green scheduling problem (FGSP) is discussed considering a carbon tax and variable tanker speed factor. To minimize the green operating cost (i.e., sum of general operating cost and carbon tax) of the tanker fleet, an integer programming model for shuttle tanker fleet green scheduling (FGSM) is established. The FGSM optimizes the number and sizes of tankers, the number and positions of floating production storage and offloading units (FPSO) at which to berth and the scheduling plan (i.e., berthing order and sailing speed) of each tanker in the fleet. Based on the column generation algorithm, a shuttle tanker fleet green scheduling algorithm is designed to solve the above model accurately. The experimental results show that considering the speed factor, the green operating cost of an example fleet decreases. For different carbon tax rates, speed optimization is an effective way to reduce the green operating cost of the fleet. The above results also show that the FGSM and algorithm can effectively solve the FGSP, improve the operation level and efficiency, and reduce the green operating cost of oil companies.

This paper reports an investigation of whether data on intelligence obtained by speeded testing have to be represented in confirmatory factor analysis (CFA) by an additional factor besides the ability factor, and whether the additional factor can be identified as a speed factor. The paper further examined whether the hypothesized speed factor influences the relationship between intelligence and working memory. Two independent datasets including data obtained by speeded intelligence testing, measures of processing speed and of working memory were investigated by means of CFA. A hybrid bifactor model was employed to represent the hypothesized speed and the ability factor of the intelligence data. Whereas the factor loadings for representing ability were set free for estimation, the factor loadings for representing speed were constrained according to theory-based expectations. The results showed that a speed factor is necessary for achieving a good fit to the data with speeded testing. The convergent validity of the speed factor was shown by data on measures of processing speed. Furthermore, it turned out that the consideration of the latent speed factor led to a decrease of the correlation between intelligence and working memory. These results suggest that speeded testing influences the assessment of intelligence and may also bias empirical findings regarding the relationships between intelligence and other constructs.

The major goal of the present study was to investigate the potential influence of age on the relationship among performance measures derived from a Hick reaction time task and general intelligence (psychometric g). Participants were 130 male and 130 female younger adults (mean age: 24.6 years) covering a wide range of individual levels of intelligence. Results from structural-equation modelling analyses clearly indicate that there is no evidence for the notion of a general speed factor underlying psychometric g. A much more sufficient model is provided by the assumption that median reaction time (RTmd) and intraindividual variability of reaction time (RTSD), though highly correlated, reflect two distinct sources of variance for psychometric g. While age was negatively associated with RTmd, no such relationship could be established for RTSD.

The present study explored the dimensionality of infant cognition by factor analyzing measures from a battery of tasks administered to a large cohort of 7-month-old preterm and full-term infants (N=203). A principal axis factor analysis yielded three factors accounting for 37% of the variance. There was one attention factor (look duration and shift rate), one speed factor (reaction time), and one memory factor (immediate recognition). The results indicate that infant cognition is better characterized as multidimensional than as unitary, and support the idea that many of the tasks used in infancy tap discrete elementary abilities.

In the field of psychometric testing, concern has been expressed over the possible compounding effect of speed on the reliable assessment of ‘level’ abilities. Present research helped to clarify this issue by factoring together primary ability scores (Cattell's CAB) and scores on low-level computerized tests (AGARD) primarily concerned with reaction times and accuracy rates. Four factors emerged, a fluid ability factor, independent of speed (but not of accuracy), a crystallized ability factor also independent of speed, a clear speed factor loading the AGARD speed measures and a tracking factor which was also moderately associated with speed. Thus, it is principally a level trait which underlies performance on these psychometric tests of ability and not a speed trait as speculated.

The question of an association between IQ and measures of timed performance derived from inspection time and reaction time was examined in a sample of 182 adults and by reanalyzing data involving 48 adults from a previously published study. Multiple regression analysis found that measures of timed performance accounted for as much as 25% of IQ variance in the normal population, but that the inclusion of borderline and mildly retarded subjects resulted in much higher correlation coefficients because of the markedly less efficient performance of these persons in tasks of this kind. This outcome raised doubts about the validity of combining data from retarded and nonretarded subjects. Results ran counter to claims that tasks of the kind used are largely uninfluenced by cognitive variables, so that findings are not necessarily explained satisfactorily in terms of a mental speed factor. It was concluded that these measures of timed performance do not, at this time, provide a basis from which a reliable culture-fair measure of intelligence might be devised.

Eight reaction time tests, yielding 11 measures of speed of information-processing, were administered to 50 pairs of adult monozygotic twins and 52 pairs of adult dizygotic twins. The twins were also administered an intelligence test. Intraclass correlations yielded heritability estimates for the mental speed measures that ranged from 0.24 to 0.90 (median = 0.51), and for measures of consistency of processing speed that ranged from 0.41 to 0.98 (median = 0.52). The heritabilities of the speed-of-processing measures were found to be positively correlated with their loadings on a general mental speed factor (r = 0.391); their relative complexity (r = 0.676); and their correlations with full-scale IQ scores (r = 0.603) and general intelligence (g) factor scores (r = 0.604).

A battery of tachistoscopic, auditory, reaction time and microcomputer-generated measures of speed of information processing (inspection time, IT) were administered to 96 college students aged between 18 and 22 yr. In addition, each S was given a battery of tests designed to provide independent evaluations of right- and left-hemispheric functioning. Criterion measures included a verbal (Vocabulary) and a nonverbal (Block Design) measure of intelligence. Results revealed a general processing speed factor in addition to task-specific sources of variability. Moreover, the IT tasks loaded on the same second-order factor as did the traditional measures of intelligence and aptitude. The findings support the theoretical view that processing speed may be a general factor in individual differences in performance on complex intellectual solving tasks. An important objective for future work in this area is to seperate and evaluate the common and specific sources of variability on IT tasks.

Schoppe's Motoric Performance Series (MLS) was administered to a group of psychiatric patients. Three factors emerged after principal component analysis with varimax rotation, the first two of which represented about 60% of the total variance and corresponded to a speed and precision factor. Zonal analysis revealed that MLS profiles of high and low trait neurotic patients were not significantly different from each other. Extraverts were inclined to exhibit inferior performance compared to introverts as witnessed by elevated scores on the subtests associated with lack of precision (steadiness and line-tracing error rates, steadiness error duration, as well as insertion of small pins). Introverted and extraverted neurotics did not differ significantly in MLS components. High and low P Ss displayed similar MLS profiles with the exception of the subtest, line-tracing (duration), in which high trait P individuals tended to perform faster. The dissimulating group (L +) required significantly longer to complete the two pin insertion tasks (both loaded on the speed factor) indicating inferior hand- and finger-dexterity, compared to low L-scoring patients. Several interactions, P × L, emerged as statistically significant. P − were less precise (steadiness error time), and required considerably less time to execute the line-tracing task, than P + Ss, for high L-scoring individuals only. P − L − individuals yielded the lowest tremor scores of all four groups.

One hundred and thirteen high school students were randomly assigned to one of two groups that were administered an intelligence test (the Multidimensional Aptitude Battery) under either timed or untimed conditions. Subsequently, all subjects were given a battery of 8 reaction time tests. Multiple regression analyses showed that combinations of RTs were approximately equally good predictors of IQ scores in both groups. Zero-order correlations between each RT test and IQ scores were also approximately equal for timed and untimed Verbal and Full-Scale scores but correlations with Performance scores were higher in the timed condition. The extent to which the different RT tests correlated with timed scores was quite highly related to the tests' loadings on a general speed factor but these loadings were not related to the tests' correlations with untimed scores. Rather, the relative complexity of the RT tests had a stronger influence on their correlations with IQ scores in the untimed condition. It is concluded that timed and untimed intelligence tests impose different information-processing demands on subjects but that the speed with which subjects can cope with these demands is equally important in both conditions.

The effect of the operating speed and the imposed load on the noise characteristics of commercially available ball bearings was studied at different speeds and loads using various lubricants. The noise level significantly increases with the speed factor; a progressively higher load factor increases the noise level but to a minor extent. Higher viscosity lubricants were beneficial in diminishing the noise level.