Graphical User Interfaces for Engineering Design: Impact of Response Delay and Training on User Performance

Today, engineers are relying more on modern computer tools and techniques to visualize complex data sets; however, few studies have examined the effect of fast, graphical design interfaces on user performance during system design. The objective in this paper is to extend our previous findings in this area by examining the impact of fast, graphical design interfaces on design efficiency and design effectiveness within the context of a job-shop design problem. We accomplish this by investigating the effect of an artificial response delay, intended to mimic computationally intensive analyses, on user performance. Experimental results indicate that user performance deteriorates significantly when a small response delay of 1.5 s is introduced: percent error and task completion time increase, on average, by 9.4% and 81 s, respectively, when the delay is present. The use of first-order, stepwise, and second-order polynomial regression models for approximating the system responses (outputs) is also investigated, and user performance is found to improve when stepwise polynomial regression models are used instead of first- or second-order models. The stepwise models yielded 12% lower error and 91 s faster completion times, on average, over the first-order models; error was 13.5% lower and completion time was 62 s faster, on average, than when second-order models were used. The results confirm our previous findings about the negative impact of response delay on task completion time while demonstrating that delay can also significantly decrease the efficacy of a metamodel-driven graphical design interface.

Relative spatial consistency - that is, the stable arrangement of objects in a 2D presentation - provides several benefits for interactive interfaces. Spatial consistency allows users to develop memory of object locations, reducing the time needed for visual search, and because spatial memory is long lasting and has a large capacity these performance benefits are enduring and scalable. This suggests that spatial consistency could be used as a fundamental principle for the design of interfaces. However, there are many display situations where the standard presentation is altered in some way: e.g., a window is moved to a new location, scaled, or rotated on a mobile or tabletop display. It is not known whether the benefits of spatial organization are robust to these common kinds of view transformation. To assess these effects, we tested user performance with a spatial interface that had been transformed in several ways, including different degrees of translation, rotation, scaling, and perspective change. We found that performance was not strongly affected by the changes, except in the case of large rotations. To demonstrate the value of spatial consistency over existing mechanisms for dealing with view changes, we compared user performance with a spatially-stable presentation (using scaling) with that of a 'reflowing' presentation (widely used in current interfaces). This study showed that spatial stability with scaling dramatically outperforms reflowing. This research provides new evidence of spatial consistency's value in interface design: it is robust to the view transformations that occur in typical environments, and it provides substantial performance advantages over traditional methods.

Usability enhancement based on usability heuristics: An examination of the underlying mechanism utilizing the psychological–refractory–period paradigm

In this chapter, an integrated approach for a holistic (involving notions of safety, resiliency and sustainability) building design is presented to select the optimal design alternative based on multiple conflicting criteria under uncertainty. A probabilistic framework of the Multi-Attribute Utility Theory (MAUT) is adopted, where MAUT is developed in conjunction with Performance-Based Engineering (PBE) approach, giving rise to a general framework, namely the PBE-MAUT. In PBE-MAUT different design alternatives may be ranked based on the expected utility. The discrepancies from the expected utility theory may be modelled through a risk-averse modelling of the utility functions based on the individual perceptions, or a more detailed description of the consequences valuable to the decision makers. Moreover, a risk-averse decision-maker towards extreme events can consider suitable quantiles or superquantiles. The distribution of the utility function is obtained from the First Order Reliability Method (FORM) which, through the design point, gives also the most critical realizations of the consequences for different degrees of risk aversion. The decision-making process is dynamic, in the sense that the optimal decision changes accordingly when new information is available. Such dynamic behavior is effectively represented using the Bayesian analysis, here modeled by combining PBE-MAUT with the Bayesian Network (BN). In this manner, the proposed framework represents a powerful Decision Support Tool (DST) for holistic building design. The BN, in conjunction with an array of sensors, can also be effectively used to determine the multi-criteria optimal decision considering the building lifecycle for a sustainable and resilient building design. The key features of the DST are demonstrated by an application to an office located on the Create Building, in Singapore.

The aim of our research during the past decades has been the specification of cognitive functions in circumscribed segments of the monkey’s cerebral cortex. Among the several methods that we have employed is the recording of cortical event-related potentials during the monkey’s performance of a spatial delayed response (DR) task. This technique permits the identification of several component potentials during limited epochs of the DR trial and, with systematic variations of task parameters, specification of the functional significance of each component in relation to the several task demands. The results, as presented here, revealed a surface-negative slow potential (SP) wave from the prefrontal area during the early intratrial delay period that was related to the level of correct DR performance. Our interpretation of this finding, that prefrontal cortex functions in motor programming for spatial responses (Stamm, 1979), seemed to have solved the “riddle of the frontal lobes.”

The dynamic properties of light propagation in AlGaN/GaN-based multiple-quantum-well waveguides have been investigated by time-resolved photoluminescence (PL) spectroscopy. The waveguides were patterned with a fixed width of 0.5 μm and length 500 μm using electron-beam lithography and inductively coupled plasma dry etching. Our results reveal a remarkable decrease in the PL intensity as well as an increase in time delay of the temporal response as the location of the laser excitation spot on the waveguide is varied. These results can be understood in terms of polariton propagation in the waveguides. From the time delay of the temporal response, it has been determined that the speed of generated polaritons, with energy corresponding to the well transitions in the waveguides, is approximately (1.26±0.16)×107 m/s. The implications of these results to waveguiding in optical devices based on the group III-nitride semiconductors are discussed.

The propagation properties of light in AlGaN/GaN multiple- quantum-well (MQW) waveguides have been studied by time- resolved photoluminescence (PL) spectroscopy. The waveguides were patterned with fixed width of 0.5micrometers but orientations varying from -30 degree(s) to 60 degree(s) relative to the a-axis of GaN by electron-beam lithography and inductively-coupled plasma (ICP) dry etching. The peak position and line-width of the emission peak were found to vary systematically with orientations of the waveguides and followed the six-fold symmetry of the wurtzite structure. This is explained in terms of anisotropy of the exciton/carrier diffusion coefficient along the different crystal orientations of the semiconductor materials. We also observed a remarkable decrease in the PL intensity as well as increase in time delay of the temporal response as the location of the laser excitation spot on the waveguide is varied. These observations can be understood in terms of exciton- polarization propagation in the waveguides. The speed of generated polaritons with energy corresponding to the well transitions in the waveguides was determined from the time delay of the temporal response to be approximately (1.26+/- 0.16 x 10<SUP>7</SUP> m/sec. The optical loss in the waveguides was determined to be about 5-8 cm<SUP>-1</SUP> for different excitation intensities. The implications of these results to waveguiding in optical devices based on the III- nitride semiconductors are discussed.

The thermospheric densities at the altitude of 410km during the geomagnetic storm on Nov. 20—21, 2003 are calculated by NCAR-TIEGCM model, and the results are compared and analyzed with the observational data from CHAMP/STAR. The results show that the model can exactly represent the distribution and variation of the density during geomagnetic storm, and the model results have a good consistency with the CHAMP data in trends and orders. But some differences do exist in detailed structure and magnitude. The model underestimated the increases of the density during geomagnetic storm with the values of 100%～125%, instead of the 250%～400% observed by CHAMP. The deviations between the model and CHAMP at high latitude are bigger than those of low latitude, and dayside bigger than nightside. It is also found that the density disturbance during geomagnetic storm presents day-night asymmetry and Southern-Northern hemisphere asymmetry. The model can exactly represent the propagation of the density disturbance from high latitude to low latitude, and the time delay in response of the density to geomagnetic storm.

Time-delayed SIS epidemic model with population awareness

This paper reports three experiments that investigated the relation between perceptual fluency and nonanalytic processing in artificial grammar classification. Nonanalytic processing was manipulated by invoking response time restrictions. In Experiment 1 there were no response time restrictions for classification decisions (response time: M=5950 ms), Experiment 2 invoked a response deadline of 2 s (response time: M=1310 ms), and Experiment 3 used a within-subjects response-signal procedure comparing classification after a 500 ms delay (response time: M=838 ms) with a 2000 ms delay (response time: M=2280 ms) The results showed that fluency created by masked priming affects classification in artificial grammar learning under conditions of relatively nonanalytic processing (Experiment 2 and the short condition of Experiment 3). The results are discussed in relation to different heuristics that participants can use in artificial grammar classification, the fluency heuristic being one of them. The experiments also provided some evidence that metaknowledge of grammaticality in artificial grammar learning may under some circumstances be enhanced by nonanalytic processing during testing.

Microvascular PO2 (PO2mv) in skeletal muscle reflects the dynamic balance between oxygen delivery and oxygen uptake. PO2mv on-kinetics in the rat spinotrapezius muscle during the rest-contraction transition are faster in both streptozotocin (STZ) and Goto-Kazazaki (GK) diabetic rats. Reduced nitric oxide (NO) availability has been implicated in these diabetic sequelae. PURPOSE: The purpose of this study was to determine the impact of insulin-resistant diabetes on PO2mv kinetics in a hindlimb locomotory muscle, and to assess the role of NO. METHODS: PO2mv (phosphorescence quenching) was measured in the extensor digitorum longus muscle (EDL) of female lean control (LC, n=10, 194 ± 3 g) and obese diabetic (OD, n=9, 356 ± 11 g) Zucker rats. PO2mv was monitored at rest and through the rest-contraction transition. PO2mv on-kinetics were determined using a monoexponential plus time delay model. EDL blood flow (radiolableled microspheres) was measured at the end of the 150 s contraction period. The experimental protocol included; 1) a pre-stimulation, 2) a control stimulation, 3) administration of L-NAME (30 mg/kg), and 4) a post-L-NAME stimulation. RESULTS: OD rats had elevated blood glucose levels (LC, 5.9 ± 0.4; OD, 25.4 ± 1.8 mmol/L). Resting PO2mv was not different in LC and OD rats (LC, 29 ± 2; OD, 23 ± 3 mmHg). During contractions, PO2mv fell to the same level in both groups (LC, 16 ± 2; OD, 17 ± 2 mmHg). OD rats had both a shorter time delay (LC, 9 ± 2; OD, 7 ± 1 s; P<0.05) and shorter mean response time (LC, 24 ± 2; OD, 17 ± 1 s; P<0.05). EDL blood flow during contractions was not different (LC, 70 ± 15; OD, 67 ± 17 ml/ min/100 g). PO2mv was lower after L-NAME in both LC and OD rats. Both time delay and mean response time were shorter in LC and OD rats, but the PO2mv time constant was shorter only in LC rats. Blood flow during contractions was not reduced by L-NAME, but the vascular conductance was reduced. CONCLUSIONS: The faster PO2mv on-kinetics observed in the EDL of OD rats is consistent with previous reports in STZ and GK rats, and may be due to a slower rise in blood flow and oxygen delivery at the onset of contractions. These data also suggest that impaired NO production in OD rats may contribute to the more rapid fall in PO2mv at the onset of muscle contractions. (Supported by the AHA, Heartland Affiliate and the KCOM Graduate Program.)

Performance Comparison of Centralized and Distributed Network Models to Support QoS in Fixed WiMAX

Information visualization techniques such as overview + detail displays have traditionally been applied and studied in domains with static data sets supporting information retrieval tasks. This study examines how these techniques can be extended to the design of interfaces for decision support systems (DSSs). Specifically, we developed a computerized decision support tool to assist Naval Tomahawk Strike Coordinators in the complex process of assigning a set of planned missions to a set of available launch platforms based on a number of different constraints and objectives, and compared user performance on two realistic scenarios (a within-subjects factor) across two versions of this tool (a between-subjects factor). The first version of the Mission-to-Platform Assignment Tool provided users with only a set of detail displays when assigning missions, whereas the second version had an additional, abstracted ‘overview’ display that allowed users to see the effect of early decisions on later decisions. The results showed that subjects performing this planning task with the overview + details display version completed scenarios, on average, 21% faster, with 22% fewer errors and with 74% fewer required workspace navigation activities than a comparable group using just the detail displays version. Subjects in the former group also rated their situational awareness 14% higher than those subjects without the overview display.

Architects are hampered in finding the optimal solutions while dealing with different sustainability dimensions simultaneously. It is the motivation of this paper to investigate what kind of barriers are disabling architects from designing sustainable buildings with a specific focus on tool uses with respect to different design phases, information needs and preferred formats. We argue that it is an absolute necessity that architects have sufficient and continuous support to make informed decisions in terms of sustainable design. In light of this argument, we conducted a study on the current Dutch architectural practice to explore the extent to which existing support tools provide sufficient guidance. With this study, we intended to gain insight into the architects’ preferences in decision support for designing high performance ‘green’ buildings.

The use of permeable stormwater channels has introduced concerns over the effects of infiltration on the hydraulic behavior of their flow and the effects of flow hydraulic conditions (e.g., the water level, channel section, flow velocity, and vegetation) on the channel infiltration capacity. A check dam system provides backwater ponding, which increases the flow water depth along a channel. In this study, a channel model was used to investigate the variation in the infiltration capacity of permeable stormwater channels under different flow hydraulic conditions. Increasing the downstream check dam height and using a grass cover increased the infiltration rate and cumulative infiltration because of the decreased velocity and increased flow depth. The presence of subsurface water did not affect the hydraulic characteristics of the channel flow but decreased the cumulative infiltration because of the fast saturation of the soil. An empirical equation was developed for predicting the infiltration capacity of grassed channels in which four hydraulic parameters (i.e., the water depth, base width, side slope, and velocity) are introduced to the modified Kostiakov model. The developed model was used to calculate the runoff reduction due to infiltration along a grassed channel with and without a check dam system. The percentage of infiltrated water increased from 8 to 14% with the check dam system. The developed model can be used to predict the infiltration capacity of permeable channels for improved stormwater management and provides a valuable decision support tool for permeable channel design.