333 research outputs found
Analysis of a VTOL hover task with predictor displays using an optimal control model of the human operator
The influence of different types of predictor displays in a longitudinal VTOL hover task is analyzed in a theoretical study. It was assumed that pitch angle and position are presented to the pilot in separate displays namely the artificial horizon and position display. The predictive information is calculated by means of a Taylor series. From earlier experimental studies it is well known that predictor displays improve human and system performance and result in reducing human workload. In this study, an optimal control model is used to prove this effect theoretically. Several cases with differing amounts of predictive and rate information are compared
Modeling the human as a controller in a multitask environment
Modeling the human as a controller of slowly responding systems with preview is considered. Along with control tasks, discrete noncontrol tasks occur at irregular intervals. In multitask situations such as these, it has been observed that humans tend to apply piecewise constant controls. It is believed that the magnitude of controls and the durations for which they remain constant are dependent directly on the system bandwidth, preview distance, complexity of the trajectory to be followed, and nature of the noncontrol tasks. A simple heuristic model of human control behavior in this situation is presented. The results of a simulation study, whose purpose was determination of the sensitivity of the model to its parameters, are discussed
The human as a detector of changes in variance and bandwidth
The detection of changes in random process variance and bandwidth was studied. Psychophysical thresholds for these two parameters were determined using an adaptive staircase technique for second order random processes at two nominal periods (1 and 3 seconds) and damping ratios (0.2 and 0.707). Thresholds for bandwidth changes were approximately 9% of nominal except for the (3sec,0.2) process which yielded thresholds of 12%. Variance thresholds averaged 17% of nominal except for the (3sec,0.2) process in which they were 32%. Detection times for suprathreshold changes in the parameters may be roughly described by the changes in RMS velocity of the process. A more complex model is presented which consists of a Kalman filter designed for the nominal process using velocity as the input, and a modified Wald sequential test for changes in the variance of the residual. The model predictions agree moderately well with the experimental data. Models using heuristics, e.g. level crossing counters, were also examined and are found to be descriptive but do not afford the unification of the Kalman filter/sequential test model used for changes in mean
Operator modeling in commerical aviation: Cognitive models, intelligent displays, and pilot's assistants
One of the goals of the National Aviation Safety/Automation program is to address the issue of human-centered automation in the cockpit. Human-centered automation is automation that, in the cockpit, enhances or assists the crew rather than replacing them. The Georgia Tech research program focused on this general theme, with emphasis on designing a computer-based pilot's assistant, intelligent (i.e, context-sensitive) displays, and an intelligent tutoring system for understanding and operating the autoflight system. In particular, the aids and displays were designed to enhance the crew's situational awareness of the current state of the automated flight systems and to assist the crew's situational awareness of the current state of the automated flight systems and to assist the crew in coordinating the autoflight system resources. The activities of this grant included: (1) an OFMspert to understand pilot navigation activities in a 727 class aircraft; (2) an extension of OFMspert to understand mode control in a glass cockpit, Georgia Tech Crew Activity Tracking System (GT-CATS); (3) the design of a training system to teach pilots about the vertical navigation portion of the flight management system -VNAV Tutor; and (4) a proof-of-concept display, using existing display technology, to facilitate mode awareness, particularly in situations in which controlled flight into terrain (CFIT) is a potential
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Troubleshooting Strategies in a Complex, Dynamical Domain
In this paper, we present results ftom two empirical studies in which subjects diagnosed faults that occurred in a computerbased, dynamical simulation of an oil-fired marine power plant, called Turbinia. Our results were analyzed in the framework of dual problem space search (DPSS), in which non-routine diagnosis was characterized as a process of generating hypotheses to explain the observed faults, and testing these hypotheses by conducting experiments. In the first study, we found that the less-efficient subjects conducted significantly more experiments, indicating a strong bottom-up bias in their diagnostic sU-ategy. In tiie second study, we examined the effects of imposing external resource bounds on subjects' diagnostic strategies. Results indicated that constraints on diagnosis time led to a reduction in the number of actions performed and components viewed, without appearing to affect diagnostic performance. Constraints on the number of diagnostic tests reduced search in the experiment space, which appeared to negatively affect performance. Taken together, these suggest results that subjects' diagnostic strategies were sensitive to consti-aints in tiie external task environment. We close with a sketch of how DPSS might be augmented to include effects due to external resource bounds
Identification of Fe and Zn Responsive Genes in Pearl Millet (Pennisetum glaucum L.) through Whole Genome Transcriptome Approach
Micronutrient malnutrition due to iron and zinc deficiencies is a serious public health problem in developing countries. In India alone, about 80% of the pregnant women and 74% of children suffer from iron and zinc deficiency. At present, knowledge of the genes controlling specific steps in the Fe and Zn pathways is still rudimentary hence studying genes of Fe and Zn density has become important. A whole genome RNA-Seq approach was carried out to understand the genes and pathways related to Fe and Zn accumulation in pearl millet. Seedlings of a high Fe and Zn grain density pearl millet inbred ICMB 1505 were exposed to four Fe and Zn stress treatments namely, āFe āZn, āFe +Zn, +Fe āZn and +Fe +Zn in hydroponics for 12 days (Figure 1). Seedlings were expressed interveinal chlorosis in the leaves due to the non-availability of Fe and Zn compared to control during the stress treatments. At that time, the leaf and root tissues in four treatments were
harvested separately. Total RNA was extracted from the treated samples followed by cDNA synthesis. Illumina HiSeq 2500 platform was used to sequence the constructed cDNA libraries. Analysis of differentially expressed genes and
pathways associated Fe and Zn is underway. Simultaneously, a set of 40 genotypes with variable Fe and Zn grain density were selected and tissue samples from different plant parts such as seed, flag leaf, root, stem sheath, panicles at anthesis and panicle at milky-stage were collected. RNA was extracted from the samples to validate the genes associated with Fe and Zn homeostasis. The information will be used for accelerated breeding programmes to improve the Fe and Zn density in pearl millet
Crystal structure of 2-methylamino-3-nitro-4-p-tolylpyrano[3,2-c]chromen-5(4H)-one
The authors thank Dr Babu Varghese, SAIF, IIT, Chennai, India, for the data collection.Peer reviewedPublisher PD
Light interception and radiation use efficiency (RUE) in maize (Zea mays. L) intercropping with greengram (Vigna radiata L.)
Intercropping is growing two or more crop species simultaneously, different canopy architectures by row configuration, changing light interception, radiation utilisation, and increased yield. The present study aimed to evaluate different intercropping systems affected light interception per cent and radiation use efficiency in maize (Zea mays L.) intercropping with greengram (Vigna radiata L.) different ratios. Field experiments were conducted for Kharif 2022 and Rabi 2022-2023 seasons, which were laid out in a split-plot design and replicated three times. Three Nitrogen levels viz., N1 - 75 % RDN (Recommended dose of Nitrogen), N2 ā 100% RDN, N3-125% RDN had taken as the main plot and three intercropping treatments were taken as subplot viz., M2G2- replacement series (two row of maize and two row of Greengram), M4G2- replacement series (four rows of maize and two row of Greengram), M2G3-paired row system (two rows of maize and three rows of Greengram), and sole maize. Both light interception and radiation use efficiency were significantly affected by intercropping systems. Light interception per cent of the main crop (maize) was significantly higher (69.0, 75.5 and 71.0 % during Kharif and 60.1, 78.1 and 76.6 during rabi) at vegetative, flowering and maturity phases, respectively. The Kharif 2022 and Rabi 2022-2023 maximum Radiation Use Efficiency (RUE) of Maize intercropping with green gram (maize + greengram) was higher in T12 (M2G3 paired row with 125 % Recommended Dose of Nitrogen) recorded as 2.46 (Kharif) and 1.43 (rabi). The outcome might be utilised to optimise the row configuration of intercropping design, explain the mechanism of intercropping on light utilisation, and improve radiation use efficiency
Genomics-Integrated Breeding for Carotenoids and Folates in Staple Cereal Grains to Reduce Malnutrition
Globally, two billion people suffer from micronutrient deficiencies. Cereal grains provide
more than 50% of the daily requirement of calories in human diets, but they often
fail to provide adequate essential minerals and vitamins. Cereal crop production in
developing countries achieved remarkable yield gains through the efforts of the Green
Revolution (117% in rice, 30% in wheat, 530% in maize, and 188% in pearl millet).
However, modern varieties are often deficient in essential micronutrients compared
to traditional varieties and land races. Breeding for nutritional quality in staple cereals
is a challenging task; however, biofortification initiatives combined with genomic tools
increase the feasibility. Current biofortification breeding activities include improving rice
(for zinc), wheat (for zinc), maize (for provitamin A), and pearl millet (for iron and zinc).
Biofortification is a sustainable approach to enrich staple cereals with provitamin A,
carotenoids, and folates. Significant genetic variation has been found for provitamin A
(96ā850 mg and 12ā1780 mg in 100 g in wheat and maize, respectively), carotenoids
(558ā6730 mg in maize), and folates in rice (11ā51 mg) and wheat (32.3ā89.1 mg)
in 100 g. This indicates the prospects for biofortification breeding. Several QTLs
associated with carotenoids and folates have been identified in major cereals, and the
most promising of these are presented here. Breeding for essential nutrition should be
a core objective of next-generation crop breeding. This review synthesizes the available
literature on folates, provitamin A, and carotenoids in rice, wheat, maize, and pearl
millet, including genetic variation, trait discovery, QTL identification, gene introgressions,
and the strategy of genomics-assisted biofortification for these traits. Recent evidence
shows that genomics-assisted breeding for grain nutrition in rice, wheat, maize, and
pearl millet crops have good potential to aid in the alleviation of micronutrient malnutrition
in many developing countries
Does Soil Micronutrient Variability in Test Locations Influence Performance of Biofortified Pearl Millet in India?
Testing of biofortified hybrids across varying pearl
millet-growing regions of India indicated the need for
maintaining sufficient Fe and Zn levels in soil to express
the cropsās full genetic potential and ensure successful
loading of micronutrients in the grain. The study
suggested the need for practicing balanced fertilization
while growing biofortified hybrids to increase grain
yield and micronutrient accumulation in grains
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