Human performance modelling as an aid in the process of manufacturing system design: A pilot study

Manufacturing system design is an ongoing activity within industry. Modelling tools based on Discrete Event Simulation are often used by practitioners during this design cycle. However, such tools do not adequately model the behaviour of 'direct' workers in manufacturing environments. There is an important need to expand the capability of modelling to include the relationships between human centred factors (demography, attitudes, beliefs, etc), their working environment (physical and organizational), and their subsequent performance in terms of productive routines. Therefore, this paper describes research that has formed a pilot modelling methodology that is an important first step in providing such a capability.     

Estimating daily fat yield from a single milking on test day for herds with a robotic milking system

The objective of this study was to estimate the daily fat yield and fat percentage from one sampled milking per cow per test day in an automatic milking system herd, when the milking times and milk yields of all individual milkings are recorded by the automatic milking system. Multiple regression models were used to estimate the 24-h fat percentage when only one milking is sampled for components and milk yields and milking times are known for all milkings in the 24-h period before the sampled milking. In total, 10,697 cow test day records, from 595 herd tests at 91 Dutch herds milked with an automatic milking system, were used. The best model to predict 24-h fat percentage included fat percentage, protein percentage, milk yield and milking interval of the sampled milking, milk yield, and milking interval of the preceding milking, and the interaction between milking interval and the ratio of fat and protein percentage of the sampled milking. This model gave a standard deviation of the prediction error (SE) for 24-h fat percentage of 0.321 and a correlation between the predicted and actual 24-h fat percentage of 0.910. For the 24-h fat yield, we found SE = 90 g and correlation = 0.967. This precision is slightly better than that of present a.m.-p.m. testing schemes. Extra attention must be paid to correctly matching the sample jars and the milkings. Furthermore, milkings with an interval of less than 4 h must be excluded from sampling as well as milkings that are interrupted or that follow an interrupted milking. Under these restrictions (correct matching, interval of at least 4 h, and no interrupted milking), one sampled milking suffices to get a satisfactory estimate for the test-day fat yield.     

Chandlerism in post-war Europe: strategic and structural change in France, Germany and the United Kingdom, 1950-1993: a comment

Whittington et al. (Industrial and Corporate Change, 1999, 8,519–550) argue that the conglomerate is a relatively transientphenomenon. However, this comment on their article argues thatexamination of their data suggests that the conglomerate maybe more persistent than is generally believed. It is arguedthat the reason for this may be found in the contribution thisstrategy may make to dealing with technologically turbulentenvironments. The results of Whittington et al. are comparedwith other studies of large firm strategies, and some testableimplications are suggested.     

Smart Playing Cards: A Ubiquitous Computing Game

We present the ‘Smart Playing Cards’ application, a ubiquitous computing game that augments a classical card game with information technological functionality by attaching RFID tags to the cards. We also mention requirements that such an application makes on a supporting software infrastructure for ubiquitous computing. Correspondence to: Nr K. R?mer or Ms S. Domnitcheva, Department of Computer Science, ETH Zürich, 8092 Zürich, Switzerland. Email: roemer@inf.ethz.ch, or domnitch@ inf.ethz.ch     

Evaluation of linguistic variations by college students with and without head injuries.

Evaluated the impact of spoken language on listeners by examining the effects of prior head injury, speech register, and active vs passive listening among 56 head-injured (HI) and 55 non-HI undergraduates. Ss rated the degree to which they liked the speaker and also the extent to which groups of negative and positive adjectives described the speaker. There were no differences between HI and non-HI Ss in how much they liked speakers using the normal register, but non-HI Ss liked the motherese speakers more than did HI Ss. Raters liked motherese speakers less when addressed directly than when they were not being directly addressed. Regardless of listener perspective, HI Ss liked motherese speakers less and rated them more negatively than non-HI Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Active site mutants of human herpesvirus-6 proteinase

OBJECTIVES: To assess the comparability of the Hybritech Tandem-R and Abbott AxSYM PSA assays in the setting of a hospital laboratory changing methods of PSA assay. METHODS: A total of 115 serum samples were tested simultaneously with both reagent kits. These include samples from patients evaluated for screening, benign prostatic hyperplasia, and follow-up of prostate cancer. RESULTS: The outcomes of the Hybritech Tandem-R PSA test ranged from 0.0 to 48.3 ng/mL with a median value of 2.4 ng/mL (mean 3.48, SD 5.46). The outcomes of the Abbott AxSYM PSA test ranged from 0.0 to 49.33 ng/mL with a median of 2.22 ng/mL (mean 3.82, SD 5.59). The outcomes of the two assays were found to be highly correlated by the Pearson correlation coefficient (r = 0.9942). When samples were divided according to PSA levels of 0.0 to less than 2.5, 2.5 to less than 4.0, 4.0 to less than 10.0, and 10.0 to less than 25.0 ng/mL, the outcomes were also highly correlated in all PSA level ranges (r = 0.9619, 0.8094, 0.9167, and 0.9081, respectively). CONCLUSIONS: The PSA values of the Tandem-R and Abbott AxSYM assays are highly correlated in the PSA level ranges of 0.0 to less than 2.5, 2.5 to less than 4.0, 4.0 to less than 10.0, and 10.0 to less than 25.0 ng/mL.     

Phytochromes and cryptochromes in the entrainment of the Arabidopsis circadian clock

Circadian clocks are synchronized by environmental cues such as light. Photoreceptor-deficient Arabidopsis thaliana mutants were used to measure the effect of light fluence rate on circadian period in plants. Phytochrome B is the primary high-intensity red light photoreceptor for circadian control, and phytochrome A acts under low-intensity red light. Cryptochrome 1 and phytochrome A both act to transmit low-fluence blue light to the clock. Cryptochrome 1 mediates high-intensity blue light signals for period length control. The presence of cryptochromes in both plants and animals suggests that circadian input pathways have been conserved throughout evolution.     

Relationship between social and personal identities: Segregation or integration.

Recognition that self-representation includes both social and personal identities raises questions about the cognitive organization of these elements. Two models of identity structure are compared: (a) a segregation model (D. Trafimow, H. C. Triandis, & S. G. Goto; see record 1991-24271-001), which assumes that (social) identities and (personal) attributes are two distinct categories, and (b) an integration model (K. Deaux, 1992), which proposes that identities and attributes often coexist in a limited set of cognitive structures. Clustering of self-relevant information in free recall was used to assess cognitive organization in a sample of 57 students. Identities and attributes clustered separately at greater-than-chance rates, consistent with the segregation model. More detailed analysis of recall data, in which individual patterns of association between identities and attributes were considered, provides stronger support for an integration model of self-representation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)