Effects of sign characteristics and training methods on safety sign training effectiveness

This study investigated whether or not training methods affected the effectiveness of symbol training and if there were any relationships between sign symbol characteristics and training effectiveness. Altogether, 26 Mainland China industrial safety signs were used and 60 participants were randomly assigned into four equal-sized groups of control, paired-associate learning, recall training and recognition training. The result was that participants from all the training groups showed significantly greater improvement in comprehension performance than those in the control group, indicating that the training methods improved comprehension of the meaning of safety signs. Participants from the recall training group performed better in the post-training test than those from other training groups. It seems that the recall task elicited a deeper level of learning than the recognition task and that questioning and feedback had a positive effect on training effectiveness. The results also showed that sign characteristics had no significant influence on training effectiveness. It was concluded that recall training is more effective in enhancing comprehension of industrial safety signs than paired-associate learning or recognition training. The findings of this study provide a basis for useful guidelines for designing symbol-training programmes and for designing more user-friendly safety signs. STATEMENT OF RELEVANCE: The present study shows that recall training was more effective in improving comprehension of industrial safety signs than paired-associate learning or recognition training and cognitive sign features did not influence training effectiveness. They provide a basis for useful guidelines for designing symbol-training programmes and for designing more user-friendly safety signs.     

Investigation of guessability of industrial safety signs: Effects of prospective-user factors and cognitive sign features

This study investigated the effects of prospective-user factors and five cognitive sign features on guessability of safety signs. Sixty Hong Kong Chinese subjects guessed the meanings and rated the sign features of 63 Mainland China safety signs. The prospective-user factors of working or site visit experience at laboratory or construction site, awareness of safety signs in daily life, injury experience due to ignorance of safety signs, and driving experience had significant effects on guessing performance. However, gender, Mainland China visit experience, and family member working at laboratory or construction site had no influence on guessing performance. The guessability scores varied with the five cognitive sign features viz. familiarity, concreteness, simplicity, meaningfulness, and semantic closeness. The guessability of safety signs was better when the signs were familiar, concrete, simple and meaningful and when the signs were associated with the underlying concepts. Overall, the findings showed that prospective-user factors and cognitive sign features are involved in effective communication of safety sign messages.

Relevance to industry

Posting of safety signs is a possible safety precaution measure that can be taken to attempt to reduce accidents and injuries in industrial undertakings. The findings of this study provide useful information for designing more user-friendly safety signs which could act as a reference for interface designers to develop more user-friendly safety signs in the future.     

Traffic sign symbol comprehension: a cross-cultural study

The objective of this study was to evaluate the comprehension levels of highway traffic sign symbols used in different countries, to identify underlying rules that affect comprehension levels, and recommend approaches to deal with the problem. The need for such an evaluation was based on today's travel culture where people are often licensed in one country and then drive—without any further training—in another country. We compared the comprehension levels of different traffic sign symbols in four countries with moderate to high levels of motorization: Canada, Finland, Israel, and Poland. Five different driver populations were sampled in each country: novice drivers, college students, tourists, problem drivers, and older drivers. There were large differences in comprehension among specific sign messages, different countries, and different driver populations. Signs were comprehended best when they were consistent with general ergonomic guidelines for display design as they relate to spatial compatibility, conceptual compatibility, physical representation, familiarity, and standardization. Illustrations of compliance with these principles and violations of these principles are presented, and their implication for traffic safety are discussed. Specific recommendations for sign design that is compliant with ergonomic principles, and for greater international cooperation in sign symbol design are made.     

Ergonomic guidelines for traffic sign design increase sign comprehension

OBJECTIVE: This research directly tests the relationship between comprehension probability of highway signs and the extent to which they comply with three ergonomic principles of design: sign-content compatibility, familiarity, and standardization. BACKGROUND: A recent study that evaluated comprehension of traffic signs in four different countries showed that comprehension level varies widely and is apparently related to the extent that the sign's design incorporates ergonomic guidelines for good design (D. Shinar, R. E. Dewar, H. Summala, and L. Zakowska 2003). METHOD: Participants were presented with 30 signs and asked to describe each sign's meaning. They then evaluated each sign in terms of each of three ergonomic principles. In addition, a group of human factors/ergonomics experts evaluated each sign on its standardization and compatibility. RESULTS: There were high correlations between the ratings of the students and the ratings of the experts on compatibility (rho = .94) and on standardization (rho = .84), validating the use of the students' evaluations of the signs on these variables. There was a great variability in signs' comprehension and high and statistically significant correlations between the comprehension level of each sign and the extent to which it complied with compatibility (R = .76), familiarity (R = .89), and standardization (R = .88) principles. CONCLUSIONS: The more signs conform to universal ergonomic principles of good design, the more likely they are to be comprehended by drivers of different cultural backgrounds. APPLICATION: Sign design should be guided by established ergonomics principles to enhance comprehension, especially for drivers who have not had any prior encounters with specific signs.     

Traffic sign symbol comprehension: a cross-cultural study

The objective of this study was to evaluate the comprehension levels of highway traffic sign symbols used in different countries, to identify underlying rules that affect comprehension levels, and recommend approaches to deal with the problem. The need for such an evaluation was based on today's travel culture where people are often licensed in one country and then drive--without any further training--in another country. We compared the comprehension levels of different traffic sign symbols in four countries with moderate to high levels of motorization: Canada, Finland, Israel, and Poland. Five different driver populations were sampled in each country: novice drivers, college students, tourists, problem drivers, and older drivers. There were large differences in comprehension among specific sign messages, different countries, and different driver populations. Signs were comprehended best when they were consistent with general ergonomic guidelines for display design as they relate to spatial compatibility, conceptual compatibility, physical representation, familiarity, and standardization. Illustrations of compliance with these principles and violations of these principles are presented, and their implication for traffic safety are discussed. Specific recommendations for sign design that is compliant with ergonomic principles, and for greater international cooperation in sign symbol design are made.     

手语识别中基于HMM的区分性训练方法

传统的隐马尔科夫模型（HMM）的训练方法基于统计概率的最大似然准则（MLE），在训练样本数目足够大的情况下，这种方法在理论上可以得到最优的结果．在手语识别研究中，采集足够大的训练样本十分困难．区分性训练可以很好地弥补由于训练样本的缺乏以及手语模型之间的近似而造成的识别系统的缺陷．最大交互信息准则（MMIE）作为区分性训练准则的一种已经被广泛的应用于语音识别领域．文中通过合理的构建手语识别中的竞争模型和易混集。提出了MMIE准则的改进形式，并将其应用于特定人与非特定人手语识别．实验证明，使用改进的MMIE准则对识别系统性能有很大的提高．     

基于级联端对端深度架构的交通标志识别方法

交通标志的正确识别是智能车辆规范行驶、道路交通安全的前提。为解决智能车采集目标图像模糊、分辨率低,造成识别精度低且时效性差的问题,构建一种基于级联深度网络的交通标志识别模型,该模型级联超分辨率处理网络ESPCN与目标检测识别网络RFCN,ESPCN网络提高输入采集图像的分辨率,为低分辨率图像实现超分辨率处理,RFCN网络提取图像全局特征,实现交通标志的检测与分类识别。平衡采样及多尺度的训练策略结合数据增强的预处理方法,增强了网络模型的鲁棒性及扩展性。经实验验证,算法模型针对常见交通标志识别率达到98.16%,召回率达到96.2%,且鲁棒性较好。     

A comparison of two training methods for improving warning symbol comprehension

This study compared the effectiveness of two different types of training in improving comprehension of warning symbols by younger (aged 20-35 years) and older adults (aged 50-70 years). The verbal label training paired the symbol with a label describing its meaning while the accident scenario training further expanded on the nature of the hazard, the required/prohibited actions, as well as the possible consequences of failing to comply. Contrary to prior research (e.g., [Lesch, M.F., 2003. Comprehension and memory for warning symbols: age-related differences and impact of training. J. Safety Res. 34, 495-505]), there was no difference in comprehension for younger and older adults prior to training, with both groups only obtaining about 40% correct responses. Both types of training improved performance on a subsequent comprehension test. However, the accident scenario training produced a higher percentage of correct responses, greater confidence in those responses, as well as a longer-lasting reduction of reaction times. In order to further improve symbol design, as well as training to address comprehension difficulties, future research should more closely examine symbol characteristics that influence comprehension.     

Emergent self-organizing feature map for recognizing road sign images

Road sign recognition system remains a challenging part of designing an Intelligent Driving Support System. While there exist many approaches to classify road signs, none have adopted an unsupervised approach. This paper proposes a way of Self-Organizing feature mapping for recognizing a road sign. The emergent self-organizing map (ESOM) is employed for the feature mapping in this study. It has the capability of visualizing the distance structures as well as the density structure of high-dimensional data sets, in which the ESOM is suitable to detect non-trivial cluster structures. This paper discusses the usage of ESOM for road sign detection and classification. The benchmarking against some other commonly used classifiers was performed. The results demonstrate that the ESOM approach outperforms the others in conducting the same simulations of the road sign recognition. We further demonstrate that the result obtained with ESOM is significantly more superior than traditional SOM which does not take into the boundary effect like ESOM did.     

气象模拟仿真技术在电力安全应急培训中的应用与研究

[目的]由于电力工作作业比较特殊,电力工作中会有许多特殊的工作场景,这些工作场景往往带有高危性。在平时训练中培训者缺乏真实感与沉浸感,为了使培训者在电力安全应急VR培训系统中,有更真实的沉浸感、仿真性,达到提升培训者学习效果和应变能力[方法]利用虚拟仿真技术研发出一套关于气象变换的模拟仿真程序,模拟出各种环境在极端气象条件下的状态,用于高度还原应急事件场景,为完成多专业、多维度、多角色协同的应急作业训练,提供高效的安全应急培训方案。[结果]经过在大量VR应急培训项目中的运用反馈,达到了预期的效果,提高培训者的课程内容的吸收率,同时获得了培训者的高度认可。[结论] VR虚拟仿真方法运用于电力安全应急培训是正确并有效的,可为实际生产提供指导。     

The use of contextual cues to improve warning symbol comprehension: making the connection for older adults

This study teased apart the effects of comprehensibility and complexity on older adults' comprehension of warning symbols by manipulating the relevance of additional information in further refining the meaning of the symbol. Symbols were systematically altered such that increased visual complexity (in the form of contextual cues) resulted in increased comprehensibility. One hundred older adults, aged 50–71 years, were tested on their comprehension of these symbols before and after training. High comprehensibility–complexity symbols were found to be better understood than low- or medium-comprehensibility–complexity symbols and the effectiveness of the contextual cues varied as a function of training. Therefore, the nature of additional detail determines whether increased complexity is detrimental or beneficial to older adults' comprehension – if the additional details provide ‘cues to knowledge’, older adults' comprehension improves as a result of the increased complexity. However, some cues may require training in order to be effective.

Practitioner Summary: Research suggests that older adults have greater difficulty in understanding more complex symbols. However, we found that when the complexity of symbols was increased through the addition of contextual cues, older adults' comprehension actually improved. Contextual cues aid older adults in making the connection between the symbol and its referent.     

Measuring and examining traffic sign comprehension with event-related potentials

Cognition, Technology & Work - Accurate understanding of traffic signs is integral to driving safety. Questionnaires and behavior tests are usually used to measure sign comprehension. However,...     

A cost analysis method of establishing training criteria

A significant problem encountered in designing operator training programmes is the lack of a method for establishing appropriate training criteria (final performance levels). This paper presents such a method which has been derived on the basis of integrating three relatively distinct technical areas: (1) learning curve modelling, (2) quality assurance concepts, and (3) economic analysis. The information requirements for making training decisions are discussed and sources of that information are proposed. The end result of applying the method is a quantifiable measure of the cost effectiveness of a training programme.     

Embedded real-time speed limit sign recognition using image processing and machine learning techniques

The number of traffic accidents in Brazil has reached alarming levels and is currently one of the leading causes of death in the country. With the number of vehicles on the roads increasing rapidly, these problems will tend to worsen. Consequently, huge investments in resources to increase road safety will be required. The vertical R-19 system for optical character recognition of regulatory traffic signs (maximum speed limits) according to Brazilian Standards developed in this work uses a camera positioned at the front of the vehicle, facing forward. This is so that images of traffic signs can be captured, enabling the use of image processing and analysis techniques for sign detection. This paper proposes the detection and recognition of speed limit signs based on a cascade of boosted classifiers working with haar-like features. The recognition of the sign detected is achieved based on the optimum-path forest classifier (OPF), support vector machines (SVM), multilayer perceptron, k-nearest neighbor (kNN), extreme learning machine, least mean squares, and least squares machine learning techniques. The SVM, OPF and kNN classifiers had average accuracies higher than 99.5 %; the OPF classifier with a linear kernel took an average time of 87 \(\upmu\)s to recognize a sign, while kNN took 11,721 \(\upmu\)s and SVM 12,595 \(\upmu\)s. This sign detection approach found and recognized successfully 11,320 road signs from a set of 12,520 images, leading to an overall accuracy of 90.41 %. Analyzing the system globally recognition accuracy was 89.19 %, as 11,167 road signs from a database with 12,520 signs were correctly recognized. The processing speed of the embedded system varied between 20 and 30 frames per second. Therefore, based on these results, the proposed system can be considered a promising tool with high commercial potential.

     

Communication effectiveness of symbolic safety signs with different user groups

Contrary to popular belief, little systematic evaluation has been undertaken of how well public information signs convey their intended message. The application of a proposed evaluation procedure, involving an initial Recognition Test and a subsequent Recall Test, to a set of occupational safety signs is reported. Respondents comprised migrants and native-born Australian attending adult literacy classes, including a group of recently-arrived Vietnamese. Despite inter-group differences in the total number of signs correctly identified on both Recognition and Recall Tests, the same signs gave rise to difficulty for all groups. The sources of difficulty are discussed in terms of distinctiveness of referents, comprehension of shape and colour code, and translation from symbol to referent. The implications of the test results for user education programmes is also considered.     

Neural mechanisms behind semantic congruity of construction safety signs: An EEG investigation on construction workers

Accurate comprehension of safety signs plays a critical part in warning construction workers of potential work hazards. However, existing studies have rarely investigated construction workers' comprehension of safety signs at construction sites. Moreover, existing evaluation methods are generally based on subjective behavior tests, questionnaires, and interviews. Therefore, this study examined the effects of semantic congruity on the comprehension of safety signs, including two sign types (prohibition vs. warning signs) and two conditions (semantic congruence vs. incongruence), combining event-related potentials and time-frequency analysis measurements. Adopting the S1-S2 paradigm, electroencephalogram data were recorded when participants decided whether S1 and S2 were semantically congruent or not. Results showed that the semantically incongruent safety sign-word pairs elicited larger N400 amplitudes and increased theta (3–8 Hz) power in 300–420 ms. The amplitude of N400 in the semantically incongruent condition of the warning sign-word pairs was more negative than that for the prohibition sign-word pairs, while there were no significant differences between the prohibition and warning sign-word pairs in the semantically congruent condition. A greater late positive potential (LPP) (550–750 ms) was also elicited in the semantically incongruent safety sign-word pairs, which was different from previous studies that observed larger LPP in congruent conditions. These results suggest complicated cognitive mechanisms of safety sign comprehension in construction workers. This study extends safety sign comprehension research by using electrophysiological approaches and provides useful indicators for researchers or safety engineers to measure the semantic congruity of proposed sign designs.     

Field testing of consumer safety signs: the comprehension of pictorially presented messages

This paper describes one of a series of studies on the investigation of desirable characteristics of a labelling system for use on potentially dangerous household products. The suitability of a range of signs based on symbolic coding of hazards has been investigated. The hazards investigated were: Fire, Poison, Caustic, Electrical and General. The first stage of the programme involved a survey of all known symbols used for these and similar applications, followed by some preliminary testing to determine a range of symbols for more detailed testing. This subsequent testing of the symbols involved their incorporation into a range of sign variants, with differing colours of image and background together with variations in the shape and colour of enclosure containing symbol. These symbolically coded sign variants were tested in the field using a structured national random sample of 4000 respondents. The data were analyzed using a variable, but systematically controlled, criterion for correct comprehension, which allowed reliable discrimination between certain of the sign variants in terms of comprehension performance. In absolute terms, comprehension of even the best of the signs was not markedly high, ranging from around 20% with s stringent criterion up to 50% if a less stringent criterion of correct comprehension was used. Some of the poorer signs tested failed to achieve better than 5% correct comprehension rate even with a lax criterion for comprehension. Prior experience of the sign was found to enhance comprehension, increasing the correct comprehension rate by a factor of 1.5-2.0 times the correct comprehension rates obtained with those respondents who affirm that they have not seen the sign before.     

Safety symbol comprehension: effects of symbol type, familiarity, and age

A new procedure for evaluating symbol comprehension, the phrase generation procedure, was assessed with 52 younger and 52 older adults. Participants generated as many phrases as came to mind when viewing 40 different safety symbols (hazard alerting, mandatory action, prohibition, and information symbols). Symbol familiarity was also assessed. Comprehension rates for both groups were lower than the 85% level recommended by the American National Standards Institute. Moreover, older participants' comprehension was significantly worse than younger participants', and the older adults also generated significantly fewer phrases. Generally, prohibition symbols were comprehended best and hazard alerting symbols worst. In addition, symbol familiarity was positively correlated with symbol comprehension. These findings indicate that important safety information depicted on signs and household products may be misunderstood if presented in symbolic form. Furthermore, certain types of symbols may be better understood (e.g., prohibition symbols) than other types (e.g., hazard alerting symbols) by both younger and older individuals. These findings signify the utility of the phrase generation procedure as a method for evaluating symbol comprehension, particularly when it is not possible or desirable to provide contextual information. Actual or potential applications of this research include using the phrase generation approach to identify poorly comprehended symbols, including identification of critical confusions that may arise when processing symbolic information.     

Age-related differences in warning symbol comprehension and training effectiveness: effects of familiarity, complexity, and comprehensibility

Age-related changes in selective attention, inhibitory efficiency, and the ability to form new associations suggest that older adults may have greater difficulty with more complex and less comprehensible symbols. We examined comprehension of symbols varying in terms of ratings of familiarity, complexity, and comprehensibility, by younger (aged 18-35) and older (aged 55-70) adults. It was found that older adults have greater difficulty than younger adults in comprehending warning symbols and that accident scenario training improves comprehension. Regression analyses indicated that familiarity and comprehensibility were important in determining performance on the pre-training comprehension test by both younger and older adults. However, training eliminated the effects of stimulus characteristics for younger adults, while older adults' comprehension continued to be significantly influenced by comprehensibility. We suggest that symbol design incorporates cues to knowledge to facilitate the linkage between new knowledge (i.e. the warning symbol) and relevant knowledge in long-term memory. Statement of Relevance: Symbol characteristics play an important role in age-related differences in warning symbol comprehension. To optimise comprehension by older adults, symbols should have a clear relationship with areal-world referent. Alternatively, symbol design could incorporate cues to knowledge to facilitate the linkage between new knowledge and relevant knowledge in long-term memory.     

American sign language (ASL) recognition based on Hough transform and neural networks

The work presented in this paper aims to develop a system for automatic translation of static gestures of alphabets and signs in American sign language. In doing so, we have used Hough transform and neural networks which is trained to recognize signs. Our system does not rely on using any gloves or visual markings to achieve the recognition task. Instead, it deals with images of bare hands, which allows the user to interact with the system in a natural way. An image is processed and converted to a feature vector that will be compared with the feature vectors of a training set of signs. The extracted features are not affected by the rotation, scaling or translation of the gesture within the image, which makes the system more flexible.The system was implemented and tested using a data set of 300 samples of hand sign images; 15 images for each sign. Experiments revealed that our system was able to recognize selected ASL signs with an accuracy of 92.3%.