Visual Search Within a Limited Window Area: Scrolling Versus Moving Window

Every day we perceive pictures on our mobile phones and scroll through images within a limited space. At present, however, visual perception via image scrolling is not well understood. This study investigated the nature of visual perception within a small window frame. It compared visual search efficiency using three modes: scrolling, moving-window, and free-viewing. The item number and stimulus size varied. Results showed variations in search efficiency depending on search mode. The slowest search occurred under the scrolling condition, followed by the moving-window condition, and the fastest search occurred under the no-window condition. For the scrolling condition, the response time increased the least sharply in proportion to item number but most sharply in proportion to the stimulus size compared to the other two conditions. Analysis of the trace of scan revealed frequent pauses interjected with small and fast stimulus shifts for the scrolling condition, but slow and continuous window movements interjected with a few pauses for the moving-window condition. We concluded that searching via scrolling was less efficient than searching via a moving-window, reflecting differences in dynamic properties of participants’ scan.

An Assessment of Vehicular Emissions and Related Health Impacts along Ilorin-Lagos Highway in Nigeria

This paper assessed in-vehicle and ambient pollution levels from vehicles along Ilorin-Lagos highway covering three distinct 3-hour periods (morning, afternoon and evening) of the day (from 7.30 am to 6.30 pm) along with reported health challenges at six (6) settlements (SP1-SP6) that covered four (4) states. In the case of ambient pollution, Gilair-3 air sampler (GAS) was used to measure sulphur (iv) oxide, (SO2) while ALTAIR 5x Multi-gas Detector (AMD) was used to measure both carbon (ii) oxide, (CO) and sulphur (iv) oxide, (SO2) for all scenarios. Vehicular volume was manually conducted to determine the number of vehicles. Questionnaire was used to assess information on the health challenges faced by the commuters. The concentrations of SO2 ranged from 0.142 - 0.550 ppm (ambient) and 0.037 - 0.097 ppm (in vehicle) using AMD and GAS respectively while CO concentration was between 2.289 - 18.055 ppm using AMD. The results for the in- vehicular pollution revealed that the concentration levels obtained for CO and SO2 inside the vehicles were 6.32 ppm and 0.126 ppm under opened-window condition and 9.53 ppm and 0.274 ppm under closed-window condition respectively (without air condition). The SO2 concentrations obtained from both ambient and in-vehicle were found to be much higher when compared with the FEPA standards; SO2 (0.01 – 0.1 ppm), USEPA standards; SO2 (0.075 ppm) while the CO level obtained from in-vehicle under the two scenarios (opened and closed windows) were below the limit of NESREA standards (10 – 20 ppm) and USEPA standards (35 ppm). Having noticed that these pollutants act under different environmental conditions, the work established statistical evidence that traffic volume affected the pollutants concentrations at most of the sampling points and that the higher the traffic, the higher the emissions and the more the risk of health challenges.

Evaluating the Perception of Ventilation for Thermal Comfort in Senate Buildings: A Case of Nigeria Universities

Window condition is one of the major factors of ventilation in office buildings. The study aimed at evaluating the natural ventilation in Senate buildings of selected Universities in South-West Nigeria. The study employed the use of questionnaires survey to solicit information on subjective feelings of the occupants on the effects of thermal opening and thermal comfort in Senate buildings offices. Direct observation was carried out to obtain information on the physical characteristics of the selected buildings. Limited research has been recorded on the study of occupants’ feelings in buildings in relation to openings in buildings. Based on the survey results, it was found that 34.0% of the windows were casement type, 30.0 % were projected 25.5% were sliding; while 9.5% were the louvred type. The study showed that 73.8% of the respondents preferred the casement window type because of its easiness in operation to other window types and improved thermal comfort on occupants. The study concluded that with adequate sizes, casement window type is the best in ameliorating the effect of thermal discomfort in Senate Buildings.

Eye movements while judging faces for trustworthiness and dominance

Past studies examining how people judge faces for trustworthiness and dominance have suggested that they use particular facial features (e.g. mouth features for trustworthiness, eyebrow and cheek features for dominance ratings) to complete the task. Here, we examine whether eye movements during the task reflect the importance of these features. We here compared eye movements for trustworthiness and dominance ratings of face images under three stimulus configurations: Small images (mimicking large viewing distances), large images (mimicking face to face viewing), and a moving window condition (removing extrafoveal information). Whereas first area fixated, dwell times, and number of fixations depended on the size of the stimuli and the availability of extrafoveal vision, and varied substantially across participants, no clear task differences were found. These results indicate that gaze patterns for face stimuli are highly individual, do not vary between trustworthiness and dominance ratings, but are influenced by the size of the stimuli and the availability of extrafoveal vision.

The Effects of Format in Computer-Based Procedure Displays

Two experiments were conducted to investigate display variables likely to influence the effectiveness of computer-based procedure displays. In Experiment 1, procedures were presented in three formats, Text, Extended-Text, and Flowchart. Text and Extended-Text are structured prose formats which differ in the spatial density of presentation. The Flowchart format differs from the Text format in both syntax and spatial representation. Subjects were required to use the procedures to diagnose a hypothetical system anomaly. The results indicate that performance was most accurate with the Flowchart format. Although overall completion times did not differ significantly across formats, the Flowchart format required significantly less time for step implementation. In Experiment 2, procedure window size was varied (6-line, 12-line, and 24-line) in addition to procedure format. In the six line window condition, Experiment 2 replicated the findings of Experiment 1. Procedures in the Flowchart format were completed with greater accuracy than procedures in either of the text formats. As predicted, completion times for Flowchart procedures decreased with increasing window size; however, accuracy of performance decreased substantially. Implications for the design of computer-based procedure displays are discussed.

Reading Self-Paced Moving Text on a Computer Display

Readability of text moved horizontally along a single line on a computer display was studied as a function of two line lengths and three jump lengths. In the experiment text was advanced in continuous jumps of one or several characters at a time and the speed of text display was controlled in real time by subjects via a control knob. The results showed that jump lengths of five and nine character spaces resulted in a higher reading rate than the one-character jump condition. Furthermore, text appearing in 20-character windows was read as fast as text in 40-character windows. However, when text was advanced one character space at a time, the small window condition resulted in higher comprehension than the large window condition. Implications of these results for reading self-paced computer displays are discussed.