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Background:The review process can be completely open, double-blinded, or somewhere in between. Double-blinded peer review, where neither the authors’ nor peer reviewers’ identities are shared with each other, is thought to be the fairest system, but there is evidence that it does not affect reviewer

In this letter, we present the system infrastructure for a swarm of quadrotors, which perform all estimation on board using monocular visual inertial odometry. This is a novel system since it does not require an external motion capture system or GPS and is able to execute formation tasks without inter-robot collisions. The swarm can be deployed in nearly any indoor or outdoor scenario and is scalable to higher numbers of robots. We discuss the system architecture, estimation, planning, and control for the multirobot system. The robustness and scalability of the approach is validated in both indoor and outdoor environments with up to 12 quadrotors.

Factors that affect faregate transaction times and hence the capacity of transit station faregates are described. These include both technological factors, such as the type of ticket processing mechanism (e.g., swipe readers versus ticket transport systems), and human factors, such as the extent of a customer’s interaction with information displayed at the faregate. Fieldwork conducted at the Bay Area Rapid Transit (BART) and New York City Transit systems has provided empirical data. The purpose of the research was to help BART assess alternative technologies for modernization of its 30-year-old fare collection system. As part of this assessment, BART was interested in obtaining higher throughput per faregate to minimize the number of new faregates that would be needed to meet expected increases in demand. The research suggests that although swipe readers are ultimately capable of higher throughput rates than ticket transport systems, human factors limit the actual throughput that can be obtained with either of these systems.

One of the reasons transit organizations collect customer-satisfaction information is to help set priorities for service improvements. Customer-satisfaction survey results can help managers choose from among a long list of service attributes (e.g., vehicle cleanliness or on-time performance) to more optimally focus their organization’s attention and resources. To make these choices, managers need to know how important each service characteristic is to their customers. Common techniques for gauging the relative importance of various service characteristics to transit customers are examined. Empirical data from the Bay Area Rapid Transit District are used to compare and contrast several of these techniques. The analysis suggests that a relatively simple approach using a ranking of bivariate correlation coefficients from high to low may be the most advantageous technique for ranking the relative importance of transit attributes from a customer perspective.

Despite the availability of, and benefits associated with, prepaid storedvalue fare cards, many transit riders continue to select traditional singleride or round-trip tickets for payment of their fares. At the San Francisco Bay Area Rapid Transit District (BART), an effort was made to assess why many riders select low-value fare instruments and to evaluate potential actions to increase the share of riders buying higher-value tickets. The qualitative and quantitative research techniques utilized at BART to explore this issue are described. Focus groups were conducted to identify important decision-making factors, which were later quantified through a telephone survey. Fear of losing high-value tickets coupled with a lack of information regarding the availability of these tickets appears to limit high-value ticket sales. Some possible approaches to encouraging the purchase of high-value tickets may include a last-ride-free feature and increased awareness of the availability of discount tickets at off-site sales outlets. This study provides insight into the decision-making process of customers when purchasing stored-value tickets and can help inform the policy-making process regarding ticket systems.

The San Francisco Bay Area Rapid Transit District (BART) recently revised the techniques it uses to collect data on qualitative areas of performance that are difficult to measure, such as station cleanliness, train cleanliness, graffiti removal, and restroom cleanliness. This paper documents the methodological changes implemented by BART and compares the accuracy of the new and the old techniques. Empirical evidence is presented demonstrating that the new data collection methods yield more reliable and objective statistics than the old system of measurement. Findings from this study suggest that reliable measurement of qualitative areas is possible. When carefully collected, these kinds of measurements can become an important component of an organization’s overall strategy to monitor and improve service quality.

Doubt continues to surround the assassination of President Kennedy to this day. Unfortunately, the controversy was not diminished by the multiple commissions and panels that were convened to investigate it. This was in large part because these various panels continued to propagate much of the confusion and lack of precision that plagued the initial medical reports, and introduced some new confusion of their own. Much of this controversy was driven by incomplete information, poor documentation and analysis, and the puzzling decision to withhold key medical evidence both from investigators and the public. However, the preponderance of evidence does show that the single-shooter, three-bullet theory is plausible both medically and scientifically. Language: en

A 29-year -o ld m a n presen ted with a 3 -month h i s to ry o f increas ing pa in and stiffness o f the neck. There was a decrease in range o f m o t i o n u p o n f lexion and extens ion o f the neck bu t no neuro log ica l deficits were noted . P la in r a d i o g r a p h s o f the cervical spine were o b t a i n e d and revealed an expand ing lesion involv ing the spinous process o f C2 (Fig. 1). The rest o f the cervical spine was normal . C o m p u t e d t o m o g r a p h y (CT) o f this reg ion was p e r f o r m e d and conf i rmed a lytic des t ruc t ive lesion involv ing the sp inous process o f C2 wi th irregu la r i ty o f c o n t o u r and an assoc ia ted soft t issue mass (Fig. 2). The l amina o f C2 was pa r t i a l ly involved. Par t i a l des t ruc t ion o f the sp inous process o f C3 was also seen due to the enc r o a c h m e n t o f the mass at C2. A p reope ra t i ve w o r k u p for exc is ional b iopsy o f the lesion i n c l u d e d a n o r m a l bone survey. A bone scan showed an a rea o f increased u p t a k e in the p r o x i m a l e n d o f the r ight t ibia. R a d i o g r a p h s o f the t ib ia a t the site o f t ake -up were negat ive and the pat ient was a s y m p t o m a t i c at this locat ion.