Evaluation of the electronic long cane: improving mobility in urban environments

ABSTRACT

A wide range of portable and wearable electronic travel aids have been developed to enable visually impaired people to move around public spaces without a sighted guide. However, few of them have gone beyond the prototype stage and the long cane and guide dog are still the main mobility aids. Despite the importance of evaluation to determine, for instance, effective functioning and end-user satisfaction, a standard approach has not yet been developed for mobility aids. The paper reports the evaluation of a low-cost electronic long cane, developed by the authors and colleagues in Brazil. It used a two-part methodology involving an experimental investigation of performance of the electronic long cane and a questionnaire to explore user satisfaction. The results of the experiments and questionnaire demonstrated both the cane’s usefulness and the need for modifications to improve its functioning. This work is also important for the development of methodologies for effective evaluation, as this is the first evaluation of a mobility device developed and carried out in Brazil. In addition, it is one of only a small number of evaluations in real locations with real obstacles. Finally, a series of recommendations for evaluating mobility devices is presented.

What this paper adds?

A standard approach to evaluating electronic travel for visually impaired people has not yet been developed and the most appropriate approach may depend on the objectives of the evaluation. Existing approaches generally use participants with no previous experience of using the device being evaluated and is carried out indoors with artificial obstacles. The training or device familiarisation period usually provided might be insufficient for participants to obtain optimal device performance or an effective comparison to be made of different devices. The approach to evaluating an electronic long cane reported in this paper has three main advantages over previous methods. The participants were experienced users of the electronic long cane who had been using it to support their daily mobility for at least a month. The evaluation was carried out in two different real urban environments with real obstacles. This has the advantages of being close to real-life cane use and participants being able to make informed comments and suggestions for improvements as a result of their experience. A questionnaire included questions on user satisfaction with and evaluation of a number of different cane features based on their experiences of cane use over a period. The work is also significant as the first detailed mobility device evaluation carried out in Brazil and in the presentation of a series of recommendations divided into themes for effective evaluation of mobility devices.     

Ergonomic techniques in the determination of optimum work surface heights

An investigation is described to ascertain optimum work surface heights in the kitchen, using several ergonomic techniques.     

Ergonomic risk factors for the wrists of hairdressers

This study utilized a portable data logger to measure the wrist angles and forearm flexor and extensor electromyography (EMG) of 21 hairstylists. The hairstylists were divided into two groups, one with 11 barbers (9 males and 2 females) specializing in men's hairdressing, and one with 10 hairdressers (2 males and 8 females) specializing in women's hairdressing. The standard haircut task was divided into three subtasks: hair cutting, washing and blow-drying. The mechanical exposures of the overall task and subtasks were quantified to compare how subtasks, occupational groups, and gender groups differ. Experimental results show that the average time to finish a woman's haircut (51.4 min) is significantly longer than that for a man's haircut (35.6 min) (p < 0.005). Female hairstylists had significantly greater EMG activity than male hairstylists did (p < 0.001). The non-dominant hands of hairdressers have significantly higher overall wrist velocity than those of barbers (p < 0.005). Analytical results suggest that the relatively higher force exertion and wrist velocity of female hairstylists combined with prolonged exposure may account for the higher rate of hand/wrist pain in female hairdressers than in male barbers.     

Theoretical and methodological issues related to long term creative cognition: the case of musical composition

The theme of large temporal span of cognition is emerging as a key issue in cognitive anthropology and ergonomics. We will consider it through the analysis of a musical composition process, that of Voi(rex) by Philippe Leroux, in which sketches and score writing are articulated through the use of different kinds of computer software. After presenting the data collecting method, we will consider the analysis of the resulting data concerning the writing of two movements of Voi(rex). Such an analysis will allow us: (1) to draw methodological conclusions about the time and mode of inquiry; (2) to specify the notion of situated cognition in situations essentially pre-established by the actor; (3) to set out two families of theoretical results relating to large temporal span cognitive phenomena: the first concerns the notion of an idea and its role in the development of the creative process; the second deals with the notion of the appropriation of tools and the making of situated individual cognition.

Ergonomic aspects of aircraft keyboard design: the effects of gloves and sensory feedback on keying performance

Increasing requirements for aircraft keyboards have indicated inadequacies in ergonomic standards for airborne environments, in particular for tasks involving unskilled, discontinuous data entry, with emphasis on accuracy rather than speed. Four experiments are reported from a programme of research aimed at the development and application of methodologies for assessing factors relevant to keyboard design. Experiment 1 demonstrated that the effects of various aircrew gloves on a representative aircraft data entry task are highly situation specific. Experiment 2 showed that gloves impaired performance on a high compatibility continuous keying task, with relatively high keying rates, and that this impairment was not reduced by additional auditory feedback. Experiment 3 demonstrated that the high compatibility keying task provided a successful methodology for investigating the effects of key displacement and resistance on speed and accuracy. Experiment 4 indicated the relative contributions of reduced tactility and mobility to the effects on keying and manipulative performance caused by aircrew gloves. Together, these experiments suggest that kinaesthetic and tactile feedback associated with keying are relatively unaffected by aircrew gloves, and that restrictions on mobility caused by gloves may be more important for continuous data entry involving relatively high keying rates     

Structural design and global sensitivity analysis of the composite B-pillar with ply drop-off

Vehicle lightweight and safety design becomes an increasingly critical issue nowadays. In order to improve the crashworthiness of side impact and roof crush with the consideration of the manufacturing process, a new composite B-pillar structure with ply drop-off is proposed in this paper. It improves the crashworthiness by changing the section thickness of structure and reduces the weight of B-pillar. The ply drop-off regions on the outer part and inner part of B-pillar are divided into three sub-laminates respectively, named as thick panel, taper panel and thin panel. The thickness of the panel are determined by the number of lay-up. Based on traditional sensitivity analysis, this paper derives some new equations and clearly evaluates and quantifies the importance of uncertainty design parameters. Finally, the comprehensive performance of the lightweight and crashworthiness for the composite B-pillar with ply drop-off is improved through structural optimization.     

Ergonomic risk factors in glass artware industries and prevalence of musculoskeletal disorder

Glass artware manufacturing activities are highly repetitive, labor-intensive, and demand prolonged standing during the working shift. This leads to the development of musculoskeletal disorders (MSDs) symptoms among the workers. However, there is a scarce of study on the prevalence of MSDs symptoms and their associated risk factors among the glass artware workers. To address this research gap, this study aims to evaluate the prevalence of MSDs and working conditions among Indian glass artware workers. Discomfort data is collected using Cornell Musculoskeletal Discomfort Questionnaire and working posture data is collected through direct observations using Rapid Entire Body Assessment (REBA). Multiple logistic regression model is developed for each body region to study the relationship between the associated risk factors and MSDs symptoms with the help of collected data. The findings of this study are first, MSDs symptoms are highly prevalent and severe, particularly in the lower back, thigh, and foot. Second, the average REBA grand score is 7.22, which reveals the high-risk level of worker's posture while performing the task. Third, Job characteristics and individual factors are associated with MSD symptoms in multiple logistic regression models. The results highlight the prevalence and severity level of MSDs and illustrate the demand for ergonomic interventions to alleviate musculoskeletal symptoms among these working groups.Relevance to industryThis study draws attention to work-related and other associated risk factors, which would help the researchers and managers to understand the working environment of glass artware industry. These risk factors should be considered for designing and implementing ergonomic interventions to prevent and alleviate musculoskeletal discomfort among the glass artware workers.     

Application of edge detection techniques to detection of the bright band in radar data

An approach to the problem of automatically locating the melting layer is outlined. The approach uses image analysis techniques on dual and single polarization radar data.     

Web robot detection techniques: overview and limitations

Most modern Web robots that crawl the Internet to support value-added services and technologies possess sophisticated data collection and analysis capabilities. Some of these robots, however, may be ill-behaved or malicious, and hence, may impose a significant strain on a Web server. It is thus necessary to detect Web robots in order to block undesirable ones from accessing the server. Such detection is also essential to ensure that the robot traffic is considered appropriately in the performance and capacity planning of Web servers. Despite a variety of Web robot detection techniques, there is no consensus regarding a single technique, or even a specific ??type?? of technique, that performs well in practice. Therefore, to aid in the development of a practically applicable robot detection technique, this survey presents a critical analysis and comparison of the prevalent detection approaches. We propose a framework to classify the existing detection techniques into four categories based on their underlying detection philosophy. We compare the different classes to gain insights into those characteristics that make up an effective robot detection scheme. Finally, we discuss why the contemporary techniques fail to offer a general solution to the robot detection problem and propose a set of key ingredients necessary for strong Web robot detection.     

Ergonomic evaluation of interaction techniques and 3D menus for the practical design of 3D stereoscopic displays

There has been a recent commercialization of 3D stereoscopic displays in order to implement them in a virtual reality environment. However, there is a lack of extensive research into user interfaces for 3D applications on stereoscopic display. This study focused on three representative interaction techniques (ray-casting, keypad and hand-motion techniques) utilizing a head-mounted display and 3D CAVE. In addition, the compatibility with 3D menus was also investigated based on performance and subjective assessment. Nine 3D menus were designed for the experiment in regards to three 2D metaphors (pop-up, pull-down and stack menus) and three structural layouts (list, cubic and circular menus). The most suitable technique for the 3D user interface on a stereoscopic display was the ray-casting technique and the stack menu which provided the user with good performance and subjective response. In addition, it was found that the cubic menu was not as effective as other menus when used with the three interaction techniques.Relevance to industryThis research describes a distinctive evaluation method and recommendations that guarantee the suitability for interactive 3D environments. Therefore, the results will encourage practitioners and researchers that are new to the area of 3D interface design.     

A comparison of techniques for automatic detection of stiction: simulation and application to industrial data

This paper illustrates the effect of stiction in actuators on closed loop performance and the importance of techniques, to be incorporated in the monitoring system, for automatic detection of the onset of this phenomenon. Three different techniques are compared on the basis of simulation by means of stiction models and it is shown how loop variables are affected by stiction parameters and by process characteristics. A major finding is that every technique has an uncertainty region where no decision can be taken in the absence of further information about the process. The application on industrial data, recorded on loops affected by stiction during routine plant operation, allows to confirm this result and to assess relative efficiency of the techniques. A simple test to be performed directly on the plant is also proposed to solve the remaining uncertain cases.     

Ergonomic effects of load carriage on the upper and lower back on metabolic energy cost of walking

We examined the effects of load carriage position on the energy cost of walking defined as the ratio of the 2-min steady-state oxygen consumption to the speed and economical speed. Fourteen healthy men walked on a treadmill at various speeds without and with load on the lower and upper back, which corresponded to 15% of their body mass. The energy cost of walking significantly decreased during walking with load than without load at slower speeds. A significant decrease in the energy cost of walking was also observed while carrying the load on the upper back than on the lower back at 60-80 m/min. The economical speed significantly decreased when carrying the load on the upper and lower back, and it was significantly correlated with body height. These findings suggest that an optimal carrying method is evident to reduce physical stress during walking with loads.     

Ergonomic evaluation of the ambulance interior to reduce paramedic discomfort and posture stress

OBJECTIVE: This study aims to evaluate safety and accessibility of an advanced life support (ALS) ambulance interior. BACKGROUND: The standard ambulance's interior design is unsatisfactory based on perceived discomfort and postures that constrain paramedics and medical staff, resulting in unsafe treatment of patients, mainly when being transported. METHODS: Two procedures were used to evaluate performance during a wide range of rescue tasks: a survey, based on questionnaires, interviews, and observation of paramedics performing routine tasks; and upper body and back posture analysis, based on postural considerations. RESULTS: Findings revealed that 74% of the paramedics stated that the location of the paramedic's seat is inefficient while they perform clinical procedures; 94% found the bench uncomfortable; 77% felt that the vertical distance between the bench and the stretcher is too far; and 86% needed to steady themselves when the vehicle was moving. Posture analysis showed that paramedics undergo several nonneutral back postures, including twisted back (>20 degrees) and sitting with back flexion between 20 degrees and 45 degrees. CONCLUSION: Because the interior of the ALS ambulance was found to be unsatisfactory both to paramedics and patients, alternative design issues are proposed. APPLICATION: The suggested practical layout contains four main modifications: (a) replacing the bench with two adjustable paramedic seats, (b) redesigning the medical cabinet for easy access, (c) adding an adjustable folding seat opposite the two new seats, and (d) adding a swiveling base and lifting apparatus that will accommodate the stretcher and enable better accessibility to patients by the paramedic personnel.     

Automatic network intrusion detection: Current techniques and open issues

Automatic network intrusion detection has been an important research topic for the last 20 years. In that time, approaches based on signatures describing intrusive behavior have become the de-facto industry standard. Alternatively, other novel techniques have been used for improving automation of the intrusion detection process. In this regard, statistical methods, machine learning and data mining techniques have been proposed arguing higher automation capabilities than signature-based approaches. However, the majority of these novel techniques have never been deployed on real-life scenarios. The fact is that signature-based still is the most widely used strategy for automatic intrusion detection. In the present article we survey the most relevant works in the field of automatic network intrusion detection. In contrast to previous surveys, our analysis considers several features required for truly deploying each one of the reviewed approaches. This wider perspective can help us to identify the possible causes behind the lack of acceptance of novel techniques by network security experts.     

A comparison of techniques for geometry access related to mesh generation

One of the major issues of mesh generation today is access to geometry in an accurate and efficient manner. This paper will review several of the issues associated with accessing geometry for mesh generation. This paper will also evaluate alternative techniques for accessing geometry and review how these techniques address, or do not address, the issues related to geometry access for mesh generation. The techniques for geometry access to be reviewed include: translation and healing, discrete representations, direct geometry access, and unified topology accessing geometry directly. The intent of this paper is to provide an overview to the alternative approaches and how they address the specific issues related to accessing geometry for mesh generation. It is not the intent of this paper to provide detailed algorithms related to accessing or repairing geometry data.     

Burnout among pilots: psychosocial factors related to happiness and performance at simulator training

Abstract

In this study among airline pilots, we aim to uncover the work characteristics (job demands and resources) and the outcomes (job crafting, happiness and simulator training performance) that are related to burnout for this occupational group. Using a large sample of airline pilots, we showed that 40% of the participating pilots experience high burnout. In line with Job Demands-Resources theory, job demands were detrimental for simulator training performance because they made pilots more exhausted and less able to craft their job, whereas job resources had a favourable effect because they reduced feelings of disengagement and increased job crafting. Moreover, burnout was negatively related to pilots’ happiness with life. These findings highlight the importance of psychosocial factors and health for valuable outcomes for both pilots and airlines.

Practitioner Summary: Using an online survey among the members of a European pilots’ professional association, we examined the relationship between psychosocial factors (work characteristics, burnout) and outcomes (simulator training performance, happiness). Forty per cent of the participating pilots experience high burnout. Job demands were detrimental, whereas job resources were favourable for simulator training performance/happiness.

Twitter text: 40% of airline pilots experience burnout and psychosocial work factors and burnout relate to performance at pilots’ simulator training.     

具有长时延和丢包的网络控制系统的故障检测

针对同时具有网络诱导时延和数据包丢失的异步时钟网络控制系统,假设数据包丢失率一定,网络诱导时延大于一个采样周期,根据执行器接收数据包的情况,设计了系统的故障观测器,将其建模为具有事件率约束的异步动态系统,基于该模型进行了稳定性分析,当条件满足时,整个系统是指数稳定的。在此基础上研究了系统的故障检测,当系统发生故障时,观测器残差能够迅速发生跳变,从而检测出故障的发生。仿真示例验证了所提出方法的有效性。     

Characterization and detection of taxpayers with false invoices using data mining techniques

In this paper we give evidence that it is possible to characterize and detect those potential users of false invoices in a given year, depending on the information in their tax payment, their historical performance and characteristics, using different types of data mining techniques. First, clustering algorithms like SOM and neural gas are used to identify groups of similar behaviour in the universe of taxpayers. Then decision trees, neural networks and Bayesian networks are used to identify those variables that are related to conduct of fraud and/or no fraud, detect patterns of associated behaviour and establishing to what extent cases of fraud and/or no fraud can be detected with the available information. This will help identify patterns of fraud and generate knowledge that can be used in the audit work performed by the Tax Administration of Chile (in Spanish Servicio de Impuestos Internos (SII)) to detect this type of tax crime.     

Ordering strategies and related techniques to overcome the trade-off between parallelism and convergence in incomplete factorizations

This paper is concerned with the parallel implementation of the incomplete factorization preconditioned iterative method. Although the use of such parallel ordering as multicolor ordering may increase parallelism in factorization, it often slows convergence when used in the preconditioned method, and thus may offset the gain in speed obtained with parallelization. Further, the higher the parallelism of an ordering, the slower the convergence; the lower the parallelism, the faster the convergence. This well-known trade-off between parallelism and convergence is well explained by the property of compatibility, the level of which can be clearly seen when ordering is presented in graph form (S. Doi, A. Lichnewsky, A graph-theory approach for analyzing the effects of ordering on ILU preconditioning, INRIA report 1452, 1991). In any given method, the fewer the incompatible local graphs in an ordering (i.e., the lower the parallelism), the faster the convergence (S. Doi, Appl. Numer. Math. 7 (1991) 417–436; S. Doi, in: T. Nodera (Ed.), Advances in Numerical Methods for Large Sparse Sets of Linear Systems, 7 Keio University, 1991). An ordering with no incompatible local graphs, for example, such as that implemented on vector multiprocessors by using the nested dissection technique, will have excellent convergence, but its parallelism will be limited (S. Doi, A. Lichnewsky, Int. J. High Speed Comput. 2 (1990) 143–179). To attain a better balance, a certain degree of incompatibility is necessary. In this regard, increasing the number of colors in multicolor ordering can be a useful approach (S. Fujino, S. Doi, in: R. Beauwens (Ed.), Proceeding of the IMACS Internation Symposium on Iterative Methods in Linear Algebra, March 1991; S. Doi, A. Hoshi, Int. J. Comput. Meth. 44 (1992) 143–152). Two related techniques also presented here are the overlapped multicolor ordering (T. Washio, K. Hayami, SIAM J. Sci. Comput. 16 (1995) 631–650), and a fill-in strategy selectively applied to incompatible local graphs. Experiments conducted with an SX-5/16A vector parallel supercomputer show the relative effectiveness of increasing the number of colors and also of using this approach in combination with overlapping and with fill-ins.     

Ergonomic evaluation of the effects of forearm conditions and body postures on trapezius muscle activity during smartphone texting

Neck-shoulder and upper back musculoskeletal symptoms in smartphone users have gained increasing attention. We evaluated trapezius muscle activity and fatigue using an objective method (surface electromyography, sEMG), and discomfort using a subjective method (questionnaire), in smartphone users during the performance of different text-entry tasks. Fifteen participants were recruited to perform six text-entry tasks under different forearm conditions (floating and supported) and body postures (sitting, standing, lying, and walking). We collected upper trapezius (UT) and lower trapezius (LT) sEMG data, and recorded muscle discomfort scores after each task. We found that static postures (especially sitting) during smartphone use predisposed to lower muscle activity with higher fatigue level and discomfort scores than dynamic posture; there was a significant main effect of body posture on average sEMG amplitude (aEMG) and discomfort scores of both muscles (all p < 0.05). Moreover, using a smartphone with the forearm supported can reduce muscle activity, fatigue level, and discomfort scores; there was a significant main effect of the forearm condition on aEMG and discomfort scores of both muscles (all p < 0.05). Our study indicates that smartphone use with the forearm floating for a long time in a static posture should be avoided (especially while sitting).