Jyh-Hone Wang

On the construction of control charts using linguistic variables

SUMMARY This paper studies two approaches to constructing control charts for linguistic data. Linguistic data can provide more information than the binary classification used in control charts by attributes. A generic approach for constructing attribute control charts using linguistic data is described. Several methods for calculating the values representing sample means, and for determining the centre line and the control limits are presented.

Probabilistic and membership approaches in the construction of control charts for linguistic data

Abstract Two approaches for constructing control charts for quality assurance when the observations are in the form of linguistic data are presented. Both approaches are based on fuzzy set theory and use fuzzy subsets to model the linguistic terms used to describe product quality. They differ in the interpretation of the control limits and in the procedure used to reduce the fuzzy subsets to scalars for determining the chart parameters. The results obtained with simulated data suggest that, on the basis of sensitivity to process shifts, the control charts for linguistic data perform better than conventional p control charts. The number of linguistic terms used in classifying the observations was found to influence the sensitivity of these control charts. The transformation method used to obtain the representative values and the amount of fuzziness do not seem to affect the performance of either type of control charts.

Adding Graphics to Dynamic Message Sign Messages

A human factors study assessed the effects of adding graphics to dynamic message sign (DMS) messages. Two approaches employed in the assessment—a questionnaire survey and a video-based driving simulation experiment—are reported here along with the findings. The questionnaire surveyed drivers’ preferences concerning the addition of graphics to a text message, the color of the message, alternative graphic images, placement of the graphic image, image contrast, flashing, and the framing of graphic images. One hundred and twenty-seven subjects from Rhode Island participated in the survey. Statistical analysis of survey results showed strong preference for graphic-aided messages over text-only messages; amber-color messages over green- and red-color messages; and messages with graphic on the left side over others. The analysis also identified specific graphics to accompany certain text messages. Based on the survey results, a video-based driving simulation experiment was designed to test drivers’ responses to selected DMS messages surveyed in the questionnaire. Forty-eight subjects from different age groups with different native language backgrounds took part in the experiment. Results of the experiment showed that graphic-aided messages displayed in amber or green were responded to significantly faster than other settings. Older drivers’ responses were slower and less accurate than others; however, their responses improved significantly when the DMS messages were enhanced by graphics. It was also found that graphic-aided DMS messages helped improve the responses of non-native-English-speaking drivers.

Censored life-data analysis using linguistic variables

Parameter estimates for censored life data using ordinary censoring methods (noninformative censoring) can be biased when the cause of censoring for a unit is related to its final life (informative censoring). An algorithm is presented for obtaining estimated lifetimes for informatively censored units. It is based on linguistic variable concepts from fuzzy set theory. These estimates are combined with the lifetimes for actual field units to form a complete sample for parameter estimation purposes. >

Using clustered assembly elements in the estimation of potential design for assembly benefits

This paper addresses the variation problem in design for assembly (DFA) benefits in different products. It investigated 12 product cases that employed DFA methodology in their redesign and found that DFA benefits correlate with certain product assembly properties. It explored the correlation relationships using assembly factors consisting of clustered manual handling and insertion assembly elements. Two sets of correlation models for estimating potential DFA benefits were developed. An example is provided to illustrate the estimation procedure and its result.

Same-different reaction time to the sequential visual presentation of vowels and consonants

Subjects saw either two vowels (E and I) or two consonants (D and G) presented sequentially on a screen (ISI of either 250 or 2,000 msec) and pressed a key to indicate whether the letters were the same or different. As predicted, reactions were faster to vowel pairs than to consonant pairs. Results are explained in terms of (1) coding of letters in terms of their speech properties; (2) representation of vowel sounds but not consonant sounds in the covert rehearsal loop; (3) transfer of vowel sounds to the echoic store; and (4) faster comparison of those features represented in the echoic store.

Same-different reaction time to stimuli presented simultaneously to separate cerebral hemispheres

This research was concerned with same-different reaction time to two stimuli presented simultaneously, one to the left and one to the right visual field, so that they projected to separate cerebral hemispheres. In experiment 1, subjects compared two colour patches, two colour words, or a colour word with a colour patch. In experiment 2, subjects compared two geometric shapes, two shape words, or a geometric shape with a shape word. Comparisons of two colours or two shapes were faster than comparisons of words that named these attributes. Responses to colours were faster than to shapes, and responses to colour words were faster than to shape words. Within-mode comparisons were faster than between-mode comparisons. Direct access of the separate stimuli to the dominant hemispheres did not produce faster responses.

Rhode Island Transportation System in Natural or Human-Caused Disasters: Enhancing Preparedness and Response

The rapid advance of technology has presented authorities with many new tools that they can use to monitor and control roadways for their safe, efficient, and convenient use by motorists, working toward an intelligent transportation system that adapts to dynamic situations that best serve motorists. Recent natural and human-caused disasters have demonstrated that there are significant challenges yet to be overcome by the advancing technology of transportation systems. A significant problem is a lack of clear, efficient communication during emergencies. The public requires timely information and guidance during and after a catastrophic event. This research investigated the feasibility of enhancing transportation system preparedness by creating messages to aid motorists during natural or human-caused disasters by supplementing the existing message display libraries for variable message signs (VMSs) and dynamic message signs (DMSs). This investigation considered the current transportation emergency communication environment and attempts to enhance communication and preparedness by improving the design and display of messages on VMSs and DMSs. The study examined 465 Rhode Island drivers by using a computer survey and 157 Rhode Island drivers by using driving simulation to research important factors in the design and deployment of message displays. The results indicated that the supplementation of communication through the use of VMSs and DMSs is a viable alternative and that there are design factors that can be used to help develop new and improve existing messages through further testing and implementation.