Working on the Chain Gang? An Examination of Rising Effort Levels in Europe in the 1990s

This paper presents evidence that, across many European countries, the 1990s have witnessed an intensification of labour effort, and investigates explanations for this process. Using data drawn from The European Survey on Working Conditions, we construct an index of work effort and show that it has reasonable properties in relation to other variables. We find that Britain has experienced the fastest rise in work effort, while in western Germany, Denmark and Greece there has been very little intensification of work effort. We show that work effort is higher in jobs that use computers more frequently, and in jobs that are more open to competitive pressures. Work effort has increased faster in countries where trade union density has declined the most. These factors are able to explain a large portion of the variation in the change of work effort between countries, but there remains a significant shift in work effort that is not accounted for by available explanatory variables.Work effort, international comparisons

Small Depth Quantum Circuits

Small depth quantum circuits have proved to be unexpectedly powerful in comparison to their classical counterparts. We survey some of the recent work on this and present some open problems.National Security Agency; Advanced Research and Development Agency under Army Research Office (DAAD 19-02-1-0058

Welfare and warfare an uneasy mix: personal experiences of and organisational responses to emotional and mental health issues in young ex-service personnel

'Shell-shock', which is now known as Post Traumatic Stress Disorder (PTSD), was first identified during the First World War and since this time the mental health of service personnel has been an issue of concern, particularly during times of armed conflict. This is an exploratory piece of research, the purpose of which is to provide information from a range of stakeholders, primarily ex-service personnel but also their families and welfare staff about the mental health needs of young military personnel

The Center/TRACON Automation System (CTAS): A video presentation

NASA Ames, working with the FAA, has developed a highly effective set of automation tools for aiding the air traffic controller in traffic management within the terminal area. To effectively demonstrate these tools, the video AAV-1372, entitled 'Center/TRACON Automation System,' was produced. The script to the video is provided along with instructions for its acquisition

Airborne Four-Dimensional Flight Management in a Time-based Air Traffic Control Environment

Advanced Air Traffic Control (ATC) systems are being developed which contain time-based (4D) trajectory predictions of aircraft. Airborne flight management systems (FMS) exist or are being developed with similar 4D trajectory generation capabilities. Differences between the ATC generated profiles and those generated by the airborne 4D FMS may introduce system problems. A simulation experiment was conducted to explore integration of a 4D equipped aircraft into a 4D ATC system. The NASA Langley Transport Systems Research Vehicle cockpit simulator was linked in real time to the NASA Ames Descent Advisor ATC simulation for this effort. Candidate procedures for handling 4D equipped aircraft were devised and traffic scenarios established which required time delays absorbed through speed control alone or in combination with path stretching. Dissimilarities in 4D speed strategies between airborne and ATC generated trajectories were tested in these scenarios. The 4D procedures and FMS operation were well received by airline pilot test subjects, who achieved an arrival accuracy at the metering fix of 2.9 seconds standard deviation time error. The amount and nature of the information transmitted during a time clearance were found to be somewhat of a problem using the voice radio communication channel. Dissimilarities between airborne and ATC-generated speed strategies were found to be a problem when the traffic remained on established routes. It was more efficient for 4D equipped aircraft to fly trajectories with similar, though less fuel efficient, speeds which conform to the ATC strategy. Heavy traffic conditions, where time delays forced off-route path stretching, were found to produce a potential operational benefit of the airborne 4D FMS

Counting, Fanout, and the Complexity of Quantum ACC

We propose definitions of \QAC^0, the quantum analog of the classical class \AC^0 of constant-depth circuits with AND and OR gates of arbitrary fan-in, and \QACC[q], the analog of the class \ACC[q] where \Mod_q gates are also allowed. We prove that parity or fanout allows us to construct quantum \MOD_q gates in constant depth for any $q$, so \QACC[2] = \QACC. More generally, we show that for any $q,p > 1$, \MOD_q is equivalent to \MOD_p (up to constant depth). This implies that \QAC^0 with unbounded fanout gates, denoted \QACwf^0, is the same as \QACC[q] and \QACC for all $q$. Since \ACC[p] \ne \ACC[q] whenever $p$ and $q$ are distinct primes, \QACC[q] is strictly more powerful than its classical counterpart, as is \QAC^0 when fanout is allowed. This adds to the growing list of quantum complexity classes which are provably more powerful than their classical counterparts. We also develop techniques for proving upper bounds for \QACC^0 in terms of related language classes. We define classes of languages \EQACC, \NQACC and \BQACC_{\rats}. We define a notion of $\log$-planar \QACC operators and show the appropriately restricted versions of \EQACC and \NQACC are contained in \P/\poly. We also define a notion of $\log$-gate restricted \QACC operators and show the appropriately restricted versions of \EQACC and \NQACC are contained in \TC^0

Piloted simulation of an air-ground profile negotiation process in a time-based Air Traffic Control environment

Historically, development of airborne flight management systems (FMS) and ground-based air traffic control (ATC) systems has tended to focus on different objectives with little consideration for operational integration. A joint program, between NASA's Ames Research Center (Ames) and Langley Research Center (Langley), is underway to investigate the issues of, and develop systems for, the integration of ATC and airborne automation systems. A simulation study was conducted to evaluate a profile negotiation process (PNP) between the Center/TRACON Automation System (CTAS) and an aircraft equipped with a four-dimensional flight management system (4D FMS). Prototype procedures were developed to support the functional implementation of this process. The PNP was designed to provide an arrival trajectory solution which satisfies the separation requirements of ATC while remaining as close as possible to the aircraft's preferred trajectory. Results from the experiment indicate the potential for successful incorporation of aircraft-preferred arrival trajectories in the CTAS automation environment. Fuel savings on the order of 2 percent to 8 percent, compared to fuel required for the baseline CTAS arrival speed strategy, were achieved in the test scenarios. The data link procedures and clearances developed for this experiment, while providing the necessary functionality, were found to be operationally unacceptable to the pilots. In particular, additional pilot control and understanding of the proposed aircraft-preferred trajectory, and a simplified clearance procedure were cited as necessary for operational implementation of the concept

The Illusion of Stabilization Policy?

For the period 1959-1972 money growth in the United States was positively correlated with past inflation and negatively correlated with past unemployment, whereas for the period 1973-1984 this correlation pattern was reversed. International data, moreover, show that the eight largest western economies exhibit a wide variety of patterns for these correlations, and these patterns seem to be unrelated to average inflation. Theoretical analysis reveals that a model in which the monetary authority is concerned only with controlling inflation is consistent with any pattern of sample correlations of money growth with past inflation and past unemployment. This analysis suggests that international differences in these sample correlations result from differences in the sample variances of disturbances to productivity growth and to aggregate demand. Specifically, the analysis suggests that the critical difference between the pre-1973 and post-1973 periods for the United States was a decrease in the importance of transitory disturbances to aggregate demand relative to permanent disturbances to productivity growth. More generally, these results imply that we cannot readily infer the objectives of the monetary authority from observed patterns of monetary policy.

Piloted simulation of a ground-based time-control concept for air traffic control

A concept for aiding air traffic controllers in efficiently spacing traffic and meeting scheduled arrival times at a metering fix was developed and tested in a real time simulation. The automation aid, referred to as the ground based 4-D descent advisor (DA), is based on accurate models of aircraft performance and weather conditions. The DA generates suggested clearances, including both top-of-descent-point and speed-profile data, for one or more aircraft in order to achieve specific time or distance separation objectives. The DA algorithm is used by the air traffic controller to resolve conflicts and issue advisories to arrival aircraft. A joint simulation was conducted using a piloted simulator and an advanced concept air traffic control simulation to study the acceptability and accuracy of the DA automation aid from both the pilot's and the air traffic controller's perspectives. The results of the piloted simulation are examined. In the piloted simulation, airline crews executed controller issued descent advisories along standard curved path arrival routes, and were able to achieve an arrival time precision of + or - 20 sec at the metering fix. An analysis of errors generated in turns resulted in further enhancements of the algorithm to improve the predictive accuracy. Evaluations by pilots indicate general support for the concept and provide specific recommendations for improvement