A cognitive architecture for emergency response

Plan recognition, cognitive workload estimation and human assistance have been extensively studied in the AI and human factors communities, resulting in many techniques being applied to domains of various levels of realism. These techniques have seldom been integrated and evaluated as complete systems. In this paper, we report on the development of an assistant agent architecture that integrates plan recognition, current and future user information needs, workload estimation and adaptive information presentation to aid an emergency response manager in making high quality decisions under time stress, while avoiding cognitive overload. We describe the main components of a full implementation of this architecture as well as a simulation developed to evaluate the system. Our evaluation consists of simulating various possible executions of the emergency response plans used in the real world and measuring the expected time taken by an unaided human user, as well as one that receives information assistance from our system. In the experimental condition of agent assistance, we also examine the effects of different error rates in the agent's estimation of user's stat or information needs

Perceptual and performance consequences of flight in virtual worlds

There are two primary purposes for head-mounted systems in aeronautical settings. One is for helmet-mounted sights and teleoperated (head-slaved) weapons systems. Bennett, Johnson, Perrone, and Phatak (1988) evaluated head tracking performance during passive and controlled flight. In that study, comparisons were also made of head tracking performance in sterile and relatively complex virtual worlds. That study confirmed the robustness of head tracking performance across a wide variety of visual scenes. A second use of virtual world displays is for aircraft control. Aircraft controllability using head-mounted, panel-mounted, or simulated out-the-window scenes has been systematically examined. Those studies reported the range of rotorcraft flight tasks in which head-mounted virtual worlds provided some advantages. Two studies will be reported that examine the perceptual/performance effects of virtual worlds. The first examines head tracking performance with roll-stabilized versus non-roll stabilized virtual worlds. The purpose of the study was to (1) examine display strategies used in current display systems and (2) study the adaptability of observers to estimated glide slope angles using head-slaved versus head-stabilized imagery. The purpose of this study was to examine the usefulness of wide field-of-regards during final approaches to a runway

Hybrid Volitional Control of a Robotic Transtibial Prosthesis using a Phase Variable Impedance Controller

For robotic transtibial prosthesis control, the global kinematics of the tibia can be used to monitor the progression of the gait cycle and command smooth and continuous actuation. In this work, these global tibia kinematics are used to define a phase variable impedance controller (PVIC), which is then implemented as the nonvolitional base controller within a hybrid volitional control framework (PVI-HVC). The gait progression estimation and biomechanic performance of one able-bodied individual walking on a robotic ankle prosthesis via a bypass adapter are compared for three control schemes: a passive benchmark controller, PVIC, and PVI-HVC. The different actuation of each controller had a direct effect on the global tibia kinematics, but the average deviation between the estimated and ground truth gait percentage were 1.6%, 1.8%, and 2.1%, respectively, for each controller. Both PVIC and PVI-HVC produced good agreement with able-bodied kinematic and kinetic references. As designed, PVI-HVC results were similar to those of PVIC when the user used low volitional intent, but yielded higher peak plantarflexion, peak torque, and peak power when the user commanded high volitional input in late stance. This additional torque and power also allowed the user to volitionally and continuously achieve activities beyond level walking, such as ascending ramps, avoiding obstacles, standing on tip-toes, and tapping the foot. In this way, PVI-HVC offers the kinetic and kinematic performance of the PVIC during level ground walking, along with the freedom to volitionally pursue alternative activities.Comment: 7 pages, 7 figures, submitted to ICRA 202

The Great American Crime Decline : Possible Explanations

This chapter examines the most important features of the crime decline in the United States during the 1990s-2010s but also takes a broader look at the violence declines of the last three centuries. The author argues that violent and property crime trends might have diverged in the 1990s, with property crimes increasingly happening in the online sphere and thus traditional property crime statistics not being reflective of the full picture. An important distinction is made between ‘contact crimes’ and crimes that do not require a victim and offender to be present in the same physical space. Contrary to the uncertainties engendered by property crime, the declines in violent (‘contact’) crime are rather general, and have been happening not only across all demographic and geographic categories within the United States but also throughout the developed world. An analysis of research literature on crime trends has identified twenty-four different explanations for the crime drop. Each one of them is briefly outlined and examined in terms of conceptual clarity and empirical support. Nine crime decline explanations are highlighted as the most promising ones. The majority of these promising explanations, being relative newcomers in the crime trends literature, have not been subjected to sufficient empirical scrutiny yet, and thus require further research. One potentially fruitful avenue for future studies is to examine the association of the most promising crime decline explanations with improvements in self-control

Antiplatelet therapy with aspirin, clopidogrel, and dipyridamole versus clopidogrel alone or aspirin and dipyridamole in patients with acute cerebral ischaemia (TARDIS): a randomised, open-label, phase 3 superiority trial

Background: Intensive antiplatelet therapy with three agents might be more effective than guideline treatment for preventing recurrent events in patients with acute cerebral ischaemia. We aimed to compare the safety and efficacy of intensive antiplatelet therapy (combined aspirin, clopidogrel, and dipyridamole) with that of guideline-based antiplatelet therapy. Methods: We did an international, prospective, randomised, open-label, blinded-endpoint trial in adult participants with ischaemic stroke or transient ischaemic attack (TIA) within 48 h of onset. Participants were assigned in a 1:1 ratio using computer randomisation to receive loading doses and then 30 days of intensive antiplatelet therapy (combined aspirin 75 mg, clopidogrel 75 mg, and dipyridamole 200 mg twice daily) or guideline-based therapy (comprising either clopidogrel alone or combined aspirin and dipyridamole). Randomisation was stratified by country and index event, and minimised with prognostic baseline factors, medication use, time to randomisation, stroke-related factors, and thrombolysis. The ordinal primary outcome was the combined incidence and severity of any recurrent stroke (ischaemic or haemorrhagic; assessed using the modified Rankin Scale) or TIA within 90 days, as assessed by central telephone follow-up with masking to treatment assignment, and analysed by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN47823388. Findings: 3096 participants (1556 in the intensive antiplatelet therapy group, 1540 in the guideline antiplatelet therapy group) were recruited from 106 hospitals in four countries between April 7, 2009, and March 18, 2016. The trial was stopped early on the recommendation of the data monitoring committee. The incidence and severity of recurrent stroke or TIA did not differ between intensive and guideline therapy (93 [6%] participants vs 105 [7%]; adjusted common odds ratio [cOR] 0·90, 95% CI 0·67–1·20, p=0·47). By contrast, intensive antiplatelet therapy was associated with more, and more severe, bleeding (adjusted cOR 2·54, 95% CI 2·05–3·16, p<0·0001). Interpretation: Among patients with recent cerebral ischaemia, intensive antiplatelet therapy did not reduce the incidence and severity of recurrent stroke or TIA, but did significantly increase the risk of major bleeding. Triple antiplatelet therapy should not be used in routine clinical practice

Antiplatelet therapy with aspirin, clopidogrel, and dipyridamole versus clopidogrel alone or aspirin and dipyridamole in patients with acute cerebral ischaemia (TARDIS): a randomised, open-label, phase 3 superiority trial

Background: Intensive antiplatelet therapy with three agents might be more effective than guideline treatment for preventing recurrent events in patients with acute cerebral ischaemia. We aimed to compare the safety and efficacy of intensive antiplatelet therapy (combined aspirin, clopidogrel, and dipyridamole) with that of guideline-based antiplatelet therapy.Methods: We did an international, prospective, randomised, open-label, blinded-endpoint trial in adult participants with ischaemic stroke or transient ischaemic attack (TIA) within 48 h of onset. Participants were assigned in a 1:1 ratio using computer randomisation to receive loading doses and then 30 days of intensive antiplatelet therapy (combined aspirin 75 mg, clopidogrel 75 mg, and dipyridamole 200 mg twice daily) or guideline-based therapy (comprising either clopidogrel alone or combined aspirin and dipyridamole). Randomisation was stratified by country and index event, and minimised with prognostic baseline factors, medication use, time to randomisation, stroke-related factors, and thrombolysis. The ordinal primary outcome was the combined incidence and severity of any recurrent stroke (ischaemic or haemorrhagic; assessed using the modified Rankin Scale) or TIA within 90 days, as assessed by central telephone follow-up with masking to treatment assignment, and analysed by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN47823388.Findings: 3096 participants (1556 in the intensive antiplatelet therapy group, 1540 in the guideline antiplatelet therapy group) were recruited from 106 hospitals in four countries between April 7, 2009, and March 18, 2016. The trial was stopped early on the recommendation of the data monitoring committee. The incidence and severity of recurrent stroke or TIA did not differ between intensive and guideline therapy (93 [6%] participants vs 105 [7%]; adjusted common odds ratio [cOR] 0·90, 95% CI 0·67–1·20, p=0·47). By contrast, intensive antiplatelet therapy was associated with more, and more severe, bleeding (adjusted cOR 2·54, 95% CI 2·05–3·16,

\u3cem\u3eAb Initio\u3c/em\u3e Studies of High Temperature Pyrolysis Mechanisms in Heterocyclic Nitrogen-Containing Compounds.

The decomposition mechanisms of various coal constituents undergoing pyrolysis are of great concern in environmental circles (especially those coal constituents containing nitrogen). Most methods of burning coal that are efficient involve doing so at high temperatures. This invariably results in a large portion of non-combusting coal being heated to high temperatures also causing pyrolysis of the original coal constituents. The end result of such pyrolysis is the production of a number of noxious gaseous products. If we are to design methods of reducing the amount of toxins that are produced from the industrial use of coal, it is necessary to understand the pyrolysis process mechanistically. Due to the great number of coal constituents, a reasonable approach to such a mechanistic study is to use a simpler model. Pyridine makes an excellent starting model upon which to build. Our study focuses on interpretation of proposed reaction channels from experimental work on pyridine, quinoline and isoquinoline shock-tube decomposition in light of new ab initio energy calculations using Gaussian 98. The pathways thus determined support the proposed pyrolysis mechanisms and agree with experimental evidence obtained from independent groups of researchers performing shock tube pyrolysis

Computational Confirmation of C\u3csub\u3e5\u3c/sub\u3eN\u3csub\u3e2\u3c/sub\u3e Observed in Rare-Gas Matrices

The structures and vibrations of several linear centrosymmetrical isomers of C5N2 were investigated by DFT. Triplet (3Σ-g) and open-shell singlet (1Σ-g) states of NCCCCCN were found to have the lowest energies. The calculated frequencies and isotope shifts are in excellent agreement with the experimental results of prominent vibrational bands observed in rare-gas matrices [Chem. Phys. 184 (1994) 233], thus confirming the conclusion that linear centrosymmetrical NCCCCCN was generated in rare-gas matrices. However, the calculated results are not in reasonable agreement with the observed frequencies of weaker bands, suggesting these weaker bands originate from something else