Toward a real-time model-based training system

This article describes the development of a real-time model-based training system that provides adaptive “over-the-shoulder” (OTS) instructions to trainees as they learn to perform an Anti-Air Warfare Coordinator (AAWC) task. The long-term goal is to develop a system that will provide real-time instructional materials based on learners’ actions, so that eventually the initial set of instructions on a task can be strengthened, complemented, or overridden at different stages of training. The training system is based on the ACT-R architecture, which serves as the theoretical background for the cognitive model that monitors the learning process of the trainee. An experiment was designed to study the impact of OTS instructions on learning. Results showed that while OTS instructions facilitated short-term learning, (a) they took time away from the processing of current information, (b) their effects tended to decay rapidly in initial stages of training, and (c) their effects on training diminished when the OTS instructions were proceduralized in later stages of training. A cognitive model that learned from both the upfront and OTS instructions was created and provided good fits to the learning and performance data collected from human participants. Our results suggest that to fully capture the symbiotic performance between humans and intelligent training systems, it is important to closely monitor the learning process of the trainee so that instructional interventions can be delivered effectively at different stages of training. We proposed that such a flexible system can be developed based on an adaptive cognitive model that provides real-time predictions on learning and performance.     

An Integrated Extreme Rainfall Modeling Tool (SDExtreme) for Climate Change Impacts and Adaptation

Water Resources Management - The estimation of the Intensity–Duration–Frequency (IDF) relation is often necessary for the planning and design of various hydraulic structures and design...     

Dual active layer a-IGZO TFT via homogeneous conductive layer formation by photochemical H-doping

In this study, InGaZnO (IGZO) thin film transistors (TFTs) with a dual active layer (DAL) structure are fabricated by inserting a homogeneous embedded conductive layer (HECL) in an amorphous IGZO (a-IGZO) channel with the aim of enhancing the electrical characteristics of conventional bottom-gate-structure TFTs. A highly conductive HECL (carrier concentration at 1.6 × 10¹³ cm^-2, resistivity at 4.6 × 10^-3 Ω∙cm, and Hall mobility at 14.6 cm²/Vs at room temperature) is fabricated using photochemical H-doping by irradiating UV light on an a-IGZO film. The electrical properties of the fabricated DAL TFTs are evaluated by varying the HECL length. The results reveal that carrier mobility increased proportionally with the HECL length. Further, a DAL TFT with a 60-μm-long HECL embedded in an 80-μm-long channel exhibits comprehensive and outstanding improvements in its electrical properties: a saturation mobility of 60.2 cm²/Vs, threshold voltage of 2.7 V, and subthreshold slope of 0.25 V/decade against the initial values of 19.9 cm²/Vs, 4.7 V, and 0.45 V/decade, respectively, for a TFT without HECL. This result confirms that the photochemically H-doped HECL significantly improves the electrical properties of DAL IGZO TFTs.     

Characteristics of fluent skills in a complex, dynamic problem-solving task

We examined critical characteristics of fluent cognitive skills, using the Georgia Tech Aegis Simulation Program, a tactical decision-making computer game that simulates tasks of an anti-air-warfare coordinator. To characterize learning, we adopted the unit-task analysis framework, in which a task is decomposed into several unit tasks that are further decomposed into functional-level subtasks. Our results showed that learning at a global level could be decomposed into learning smaller component tasks. Further, most learning was associated with a reduction in cognitive processes, in which people make inferences from the currently available information. Eye-movement data also revealed that the time spent on task-irrelevant regions of the display decreased more than did the time spent on task-relevant regions. In sum, although fluency in dynamic, complex problem solving was achieved by attaining efficiency in perceptual, motor, and cognitive processes, the magnitude of the gains depended on the preexisting fluency of the component skills. These results imply that a training program should decompose a task into its component skills and emphasize those components with which trainees have relatively little prior experience. Actual or potential applications of this research include learning and training of complex tasks as well as evaluation of performance on those tasks.     

Self-Rectifying Effect in Resistive Switching Memory Using Amorphous InGaZnO

Resistance random access memory (ReRAM) has received attention as next-generation memory because of its excellent operating properties and high density integration capability as a crossbar array. However, the application of the existing ReRAM as a crossbar array may lead to crosstalk between adjacent cells due to its symmetric I–V characteristics. In this study, the self-rectifying effect of contact between amorphous In-Ga-Zn-O (a-IGZO) and TaO _x was examined in a Pt/a-IGZO/TaO _x /Al₂O₃/W structure. The experimental results show not only self-rectifying behavior but also forming-free characteristics. During the deposition of a-IGZO on the TaO _x , an oxygen-rich TaO _x interfacial layer was formed. The rectifying effect was observed regardless of the interface formation and is believed to be associated with Schottky contact formation between a-IGZO and TaO _x . The current level remained unchanged despite repeated DC sweep cycles. The low resistance state/high resistance state ratio was about 10¹ at a read voltage of ?0.5 V, and the rectifying ratio was about 10³ at ±2 V.     

Dissociating the components of switch cost using two-to-two cue–task mapping.

In the task switch paradigm, a switch of task is typically accompanied by a change in task cue. It has been proposed that the performance deficit usually observed when switching tasks is actually the result of changing cues. To test this possibility, we used a 2:2 cue–task mapping in which each cue indicated 2 different tasks. With advance presentation of a cue, the cost associated with changing cues disappeared, though a substantial task switch cost remained. Without advance cues, the relative contributions of task switch cost and cue change cost differed by transition frequencies. The results suggest that task execution contributes to switch cost independent of cue changes. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Procedural frameworks for simple arithmetic skills.

Rule-application skills such as simple arithmetic are often used as components of complex, goal-directed routines, and evidence suggests that goals to perform such skills can be instantiated in advance of information about specific operands. The procedural framework hypothesis is that goal instantiation evokes frameworks that guide the application of procedural knowledge, suggesting distinct processing roles for operator and operand symbols. In contrast, the uniform role hypothesis suggests that both types of symbols serve only as retrieval cues. Participants in 4 experiments solved simple Boolean or standard arithmetic problems. Serial display of problem elements showed a consistent solution-time benefit for operator-first displays compared with operands-first displays, supporting the procedural framework hypothesis for both new and highly practiced skills. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task preparation and task repetition: Two-component model of task switching.

The switch cost (the disadvantage of performing a new task vs. a repeated task) has been attributed to lack of preparation for the switched task or priming of the repeated task. These sources were examined by manipulating foreknowledge of task transition (repeat or switch), response-to-stimulus interval (RSI), and practice level. Regardless of foreknowledge, the cost decreased with RSI and practice. The reduction was greater with foreknowledge than with no foreknowledge, and the amount of switch cost did not depend on foreknowledge. These results suggest that the switch cost with foreknowledge may consist of both inadequate preparation and repetition benefit but the switch cost with no foreknowledge may reflect repetition benefit only. An ACT-R (adaptive control of thought-rational) model was proposed, accommodating both preparation and priming effect with 2 independent processes: conflict resolution among productions and decay of chunk activation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of repetition and foreknowledge in task-set reconfiguration.

To examine the roles of executive control and automatic activation in task switching, we manipulated foreknowledge as well as task transitions. In Experiments 1 and 2, performance with foreknowledge was faster than performance with no foreknowledge, but the amount of switch cost did not depend on foreknowledge. This result suggests that switch costs primarily reflect persisting activation rather than inadequate preparation. In Experiment 3, switch cost was greater with foreknowledge about task transitions alone than with foreknowledge about both task transition and identity, suggesting that foreknowledge about specific task identity did allow preparation for a switched task. We argue that task repetition and foreknowledge effects are independent. Although foreknowledge allows preparation for both repeated and switched tasks, repeating the same task has benefits over task switching regardless of foreknowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)