Analysis of routine communication in the air traffic control system

The present project has three related goals. The first is to describe the organization of routine controller-pilot communication. This includes identifying the basic units of communication and how they are organized into discourse, how controllers and pilots use language to achieve their goals, and what topics they discuss. The second goal is to identify the type and frequency of problems that interrupt routine information transfer and prompt pilots and controllers to focus on the communication itself. The authors analyze the costs of these problems in terms of communication efficiency, and the techniques used to resolve these problems. Third, the authors hope to identify factors associated with communication problems, such as deviations from conventional air traffic control procedures

Group and phase velocity mismatch fringes in triple sum-frequency spectroscopy

The effects of group and phase velocity mismatch are well-known in optical harmonic generation, but the non-degenerate cases remain unexplored. In this work we develop an analytic model which predicts velocity mismatch effects in non-degenerate triple sum-frequency mixing, TSF. We verify this model experimentally using two tunable, ultrafast, short-wave-IR lasers to demonstrate spectral fringes in the TSF output from a 500 $\mu$m thick sapphire plate. We find the spectral dependence of the TSF depends strongly on both the phase velocity and the group velocity differences between the input and output fields. We define practical strategies for mitigating the impact of velocity mismatches

The influence of ATC message length and timing on pilot communication

Pilot-controller communication is critical to safe and efficient flight. It is often a challenging component of piloting, which is reflected in the number of incidents and accidents involving miscommunication. Our previous field study identified communication problems that disrupt routine communication between pilots and controllers. The present part-task simulation study followed up the field results with a more controlled investigation of communication problems. Pilots flew a simulation in which they were frequently vectored by Air Traffic Control (ATC), requiring intensive communication with the controller. While flying, pilots also performed a secondary visual monitoring task. We examined the influence of message length (one message with four commands vs. two messages with two commands each) and noncommunication workload on communication accuracy and length. Longer ATC messages appeared to overload pilot working memory, resulting in more incorrect or partial readbacks, as well as more requests to repeat the message. The timing between the two short messages also influenced communication. The second message interfered with memory for or response to the first short message when it was delivered too soon after the first message. Performing the secondary monitoring task did not influence communication. Instead, communication reduced monitoring accuracy

Calculating potential growth rates and output gaps - A revised production function approach

Any meaningful analysis of cyclical developments, of medium term growth prospects or of the stance of fiscal and monetary policies are all predicated on either an implicit or explicit assumption concerning the rate of potential output growth. Given the importance of the concept, the measurement of potential output is the subject of contentious and sustained research interest. All the available methods have "pros" and "cons" and none can unequivocally be declared better than the alternatives in all cases. Thus, what matters is to have a method adapted to the problem under analysis, with well defined limits and, in international comparisons, one that deals identically with all countries. This is the approach adopted in the present paper where it is stated clearly that the objective is to produce an economics based, production function, method which can be used for operational EU policy surveillance purposes.growth rates, cyclical developments, production function, potential output, Denis, Grenouilleau, Mc Morrow, R�ger

An Explorative Investigation of the Warm-up Practices of Professional and Amateur Rugby League Players

This study aimed to assess warm-up practices within professional and amateur Rugby League players, specifically to determine players’ perceptions why particular methods were used and discover whether any differences existed in warm-up practices and perceptions between the two separate standards. The study used a 10 question online questionnaire to investigate 30 professional and 53 amateur players warm-up protocols and their perceptions behind their practices. To provide a richer understanding regarding the practices and perceptions surrounding warm-up protocols, the questionnaire was followed by two focus groups (professionals and amateurs), which included four participants in each. Following analysis of the questionnaire responses, it was discovered that professional players warm-up protocols were significantly longer in duration than amateur players (P = 0.009). However, for all other variables assessed including; specific warm-up protocols, static stretch duration, and perceptions and beliefs concerning warm-up protocols, there were no significant differences between professionals and amateurs. Overall findings demonstrated the widespread use of static stretching within warm-up for both professionals and amateurs; 71 of 83 players (86%) reported usage. It was also highlighted that injury prevention was the most commonly perceived benefit from performing a warm-up across both standards [(Professional; 15 of 30, 50%) (Amateur; 27 of 53, 51%)]. Findings from the focus group generally supported questionnaire responses, and it was identified that the warm-up practices and protocols of Rugby League players were influenced by others such as coaches and strength and conditioning coaches which emphasises the importance of the role such practitioners

Solar Sail Orbit Operations at Asteroids: Exploring the Coupled Effect of an Imperfectly Reflecting Sail and a Nonspherical Asteroid

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77005/1/AIAA-2002-4991-208.pd

Microwave phase contrast imaging of the subsurface using variation in soil moisture level

A new microwave subsurface imaging product is described which is evolved via time lapsed microwave measurements, over several days, of the soil subsurface. The technique exploits changes in soil moisture levels that occur naturally due to evaporative and percolation processes. A novel technique is investigated for detecting and discriminating buried targets; it provides a scaled phase weighting procedure to form a cumulative B-scan image of the subsurface. The algorithm is demonstrated on ground penetrating radar measurements acquired in the XBand spectrum over soil where reference targets and other buried artefacts are placed. Early stage experimental results suggest the approach shows promise to provide enhanced subsurface imagery with reduced clutter and noise levels

Solar sail orbit operations at asteroids

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77377/1/AIAA-2000-4420-378.pd

An explorative investigation into the warm-up practices of both professional and amateur rugby league players

PURPOSE: Rugby League (RL) players require high levels of speed, strength, power, agility and psychological readiness. Optimum preparation for performance via warm-up (WU) routines has been an area of research speculation in recent years. This study aimed to survey the WU protocols of professional and amateur RL players, to determine player’s perceptions of their featured WU procedures and to establish any significant differences in WU practices and perceptions between the two populations. METHODS: An online questionnaire was used to investigate 30 professional and 53 amateur players’ WU protocols and their perceptions behind their practices, providing both statistical and descriptive analysis. For a more in depth understanding into the practices and perceptions of the featured protocols, the questionnaire was followed up by two focus groups which included four participants in each (one professional group and one amateur). Raw data was produced from the focus groups which was then placed within higher-order themes and general dimensions. RESULTS: The questionnaire revealed a significant between-group difference for the duration of the WU’s between the two separate standards (P = 0.009). Professionals’ WU protocols were considerably longer in duration compared to the amateurs’ protocols; 67% of professional players performed WU routines for 15+ min whereas only 42% of amateur players claimed to WU for 15+ min. However, no between-group differences existed for protocols, perception variables, static stretching (SS) duration and similarity of the WU protocol (P > 0.05). The questionnaire also revealed the prevalence of SS; 83% of amateur participants and 90% of professional players claimed to perform SS during their WU. The focus group revealed that RL players’ protocols and perceptions of their regime are due to the influences of others such as coaches, strength and conditioning practitioners and physiotherapists and emphasises the importance the role such professionals play. CONCLUSIONS: The results showed that professional participants WU for a longer period in comparison to amateurs. The high prevalence of SS within RL WU protocols at both a professional and amateur standard was clearly apparent, contradicting the vast amount of literature that would advocate the removal of SS in sports requiring explosive power due to the associated links with decrements in performance. Most professional and amateur RL participants were discovered to perform SS for a duration that has been proven to impair desired physiological attributes. Furthermore, the study revealed the dynamic element of a WU is being consistently placed before SS, by both the professional and amateur domain, which has been previously linked to decreases in body temperature and associated mechanisms related mechanisms. Players associated that there WU practice was heavily influenced by RL coaches and associated practitioners. PRACTICAL APPLICTIONS: It is recommended that coaches, strength and conditioning practitioners and other key influential figures are educated on optimal evidence based WU procedures prior to prescription. Important aspects for consideration and education include WU duration, intensity, protocol order and SS elongation, volume and duration. Whilst it is important to link the research in WU to performance, practitioners should be mindful of changing regimes abruptly and the idiosyncratic nature of how athletes prefer to prepare physically and mentally