Sixteenth-Century Bulge on the Coast of Chile

This paper traces the sixteenth-century addition and removal on maps of a bulge on the southern coast of Chile. Abraham Ortelius was primarily responsible for these changes and many cartographers followed his lead.Then, Ortelius rotated the coastline of Chile from northwest to north. Later, he dropped the latitude of the islands of San Pablo and Isla de los Tiburones down six degrees. He named the Amazon River “Río de las amazons.” Finally, he removed the cities with fake Native-American-sounding names along the Pacific coast of North America. The research underlying this paper examined over seven-hundred sixteenth-century maps made by sixdozen cartographers. This paper cites five-dozen maps by four-dozen cartographers. In the traceability section of this paper, this information was condensed into a traceability diagram, which shows the chronological flow of information among a score of cartographers. Using this information, this paper traced the influence of one cartographer on another: it showed who influenced whom. It showed the spread of knowledge. Ortelius was at the center of most of this knowledge explosion

The Requirements Discovery Process

Cost and schedule overruns are often caused by poor requirements that are produced by people who do not understand the requirement process. This paper provides a high-level overview of the requirements discovery process

Paradoxical popups: Why are they hard to catch?

Even professional baseball players occasionally find it difficult to gracefully approach seemingly routine pop-ups. This paper describes a set of towering pop-ups with trajectories that exhibit cusps and loops near the apex. For a normal fly ball, the horizontal velocity is continuously decreasing due to drag caused by air resistance. But for pop-ups, the Magnus force (the force due to the ball spinning in a moving airflow) is larger than the drag force. In these cases the horizontal velocity decreases in the beginning, like a normal fly ball, but after the apex, the Magnus force accelerates the horizontal motion. We refer to this class of pop-ups as paradoxical because they appear to misinform the typically robust optical control strategies used by fielders and lead to systematic vacillation in running paths, especially when a trajectory terminates near the fielder. In short, some of the dancing around when infielders pursue pop-ups can be well explained as a combination of bizarre trajectories and misguidance by the normally reliable optical control strategy, rather than apparent fielder error. Former major league infielders confirm that our model agrees with their experiences.Comment: 28 pages, 10 figures, sumitted to American Journal of Physic

Examples of Mental Mistakes Made by Systems Engineers While Creating Tradeoff Studies

Problem statement: Humans often make poor decisions. To help them make better decisions, engineers are taught to create tradeoff studies. However, these engineers are usually unaware of mental mistakes that they make while creating their tradeoff studies. We need to increase awareness of a dozen specific mental mistakes that engineers commonly make while creating tradeoff studies. Aims of the research: To prove that engineers actually do make mental mistakes while creating tradeoff studies. To identify which mental mistakes can be detected in tradeoff study documentation. Methodology: Over the past two decades, teams of students and practicing engineers in Bahill’s Systems Engineering courses wrote the system design documents for an assigned system. On average, each of these document sets took 100 man-hours to create and comprised 75 pages. We used 110 of these projects, two dozen government contractor tradeoff studies and three publicly accessible tradeoff studies. We scoured these document sets looking for examples of 28 specific mental mistakes that might affect a tradeoff study. We found instances of a dozen of these mental mistakes. Results: Often evidence of some of these mistakes cannot be found in the final documentation. To find evidence for such mistakes, the experimenters would have had to be a part of the data collection and decision making process. That is why, in this paper, we present only 12 of the original 28 mental mistakes. We found hundreds of examples of such mistakes. We provide suggestions to help people avoid making these mental mistakes while doing tradeoff studies. Conclusions: This paper shows evidence of a dozen common mental mistakes that are continually being repeated by engineers while creating tradeoff studies. When engineers are taught about these mistakes, they can minimize their occurrence in the future

Application of Fuzzy Technology to Risk-Based Design and Decision Problems

A study was undertaken to assess the impact of employing fuzzy technologies in areas of complex weapon system design. The technology was examined for use in a life-cycle cost exercise with the objective of providing a foundation from which to make service life assessments and recommendations on future weapon systems. The issues associated with this problem can be highly subjective and often exhibit a high degree of functional as well as variable uncertainty, ambiguity and noise. The study demonstrated that there is a potential role for the technology, but only in a hybridized environment not as a stand-alone solution methodology

A Road Map for Implementing Systems Engineering

Studies by academia, industry, and government indicate that applying a sound systems engineering process to development programs is an important tool for preventing cost and schedule overruns and performance deficiencies. There is an enormous body of systems engineering knowledge. Where does one start? How can the principles of systems engineering be applied in the Sandia environment? This road map is intended to be an aid to answering these questions

Saccadic eye movements estimate prolonged time awake

Prolonged time awake increases the need to sleep. Sleep pressure increases sleepiness, impairs human alertness and performance and increases the probability of human errors and accidents. Human performance and alertness during waking hours are influenced by homeostatic sleep drive and the circadian rhythm. Cognitive functions, especially attentional ones, are vulnerable to circadian rhythm and increasing sleep drive. A reliable, objective and practical metrics for estimating sleepiness could therefore be valuable. Our aim is to study whether saccades measured with electro-oculography (EOG) outside the laboratory could be used to estimate the overall time awake without sleep of a person. The number of executed saccades was measured in 11 participants during an 8-min saccade task. The saccades were recorded outside the laboratory (Naval Academy, Bergen) using EOG every sixth hour until 54 hr of time awake. Measurements were carried out on two occasions separated by 10 weeks. Five participants participated in both measurement weeks. The number of saccades decreased during sustained wakefulness. The data correlated with the three-process model of alertness; performance differed between participants but was stable within individual participants. A mathematically monotonous relation between performance in the saccade task and time awake was seen after removing the circadian rhythm component from measured eye movement data. The results imply that saccades measured with EOG can be used as a time-awake metric outside the laboratory.Peer reviewe

Deficits in the activation of human oculomotor nuclei in chronic traumatic brain injury

Binocular eye movements form a finely tuned system that requires accurate coordination of the oculomotor dynamics of the brainstem control nuclei when tracking the fine binocular disparities required for 3D vision. They are particularly susceptible to disruption by brain injury and other neural dysfunctions. Here, we report functional magnetic resonance imaging activation of the brainstem oculomotor control nuclei by binocular saccadic and vergence eye movements, and significant reductions in their response amplitudes in mild or diffuse traumatic brain injury (dTBI). Bilateral signals were recorded from a non-TBI control group (n = 11) in the oculomotor control system of the superior colliculi, the oculomotor nuclei, the abducens nuclei, and in the supra-oculomotor area (SOA), which mediate vergence eye movements. Signals from these nuclei were significantly reduced overall in a dTBI group (n = 12) and in particular for the SOA for vergence movements, which also showed significant decreases in velocity for both the convergence and divergence directions

Saccadic Eye Movements Minimize the Consequences of Motor Noise

The durations and trajectories of our saccadic eye movements are remarkably stereotyped. We have no voluntary control over these properties but they are determined by the movement amplitude and, to a smaller extent, also by the movement direction and initial eye orientation. Here we show that the stereotyped durations and trajectories are optimal for minimizing the variability in saccade endpoints that is caused by motor noise. The optimal duration can be understood from the nature of the motor noise, which is a combination of signal-dependent noise favoring long durations, and constant noise, which prefers short durations. The different durations of horizontal vs. vertical and of centripetal vs. centrifugal saccades, and the somewhat surprising properties of saccades in oblique directions are also accurately predicted by the principle of minimizing movement variability. The simple and sensible principle of minimizing the consequences of motor noise thus explains the full stereotypy of saccadic eye movements. This suggests that saccades are so stereotyped because that is the best strategy to minimize movement errors for an open-loop motor system