Handbuch software ergonomie usability engineering



ISBN: 254666680


Handbuch software ergonomie usability engineering

DUXU : Design, User Experience, and Usability: Understanding Users and Contexts pp Cite as. Modern machine tools have become highly automated versatile production systems, often showing deficits in intuitive control opportunities. To match human-machine interfaces to increasing functionality requirements, the software complexity can be reduced by task-oriented human-machine interface design. Content of this paper is the evaluation of task-orientation and its influence on usability dimensions in a field and laboratory investigation.

For this purpose, a function-oriented software for cutting machines, currently used in production, was compared to a task-oriented prototype by means of the IsoMetrics S. Results show an effect of task-orientation on conformity with user expectations and learnability in the laboratory study. Furthermore performance measurement shows that task-orientation leads to decreasing execution times.

Technological advantages lead to tremendous changes in the production industry. Modern machine tools have been developing to exceedingly automated production systems with highly complex functionality due to the increasing demand for high production rates and quality.

However, the human-machine interface is not adapted to these circumstances yet, resulting in a lack of intuitive controlling features, causing high levels of mental strain for the operator [ 1 ]. Mental strain can be summarized as the intensity of cognitive processing amongst all stages of human information processing during informational operations. The quantity of stress hereby depends on several objective influence variables such as working and environment conditions.

In this context overstraining tasks lead to the same consequences for performance as subchallenging operations [ 3 ]. These circumstances point out the necessity for more intuitive human-machine interaction concepts regarding increasing complexity of production systems, respective machine tool controlling. This can be realized by adjusting the human-machine interface. The standard DIN EN ISO describes the steps of the user-centered design process for interactive systems.

According to this approach, usability just like accessibility of products, are dependent on the context of use, specifically on user requirements, task to be completed and environment requirements [ 5 ]. Since actual standards already deal with ergonomic information display, as well as information input, recommendations for interface design have already been implemented in several technical systems.

Moreover, research about information perception has been comprehensively conducted within the last decades in numerous eye tracking studies prove. However, less effort has been spend regarding the implementation of central cognitive processes as a design dimension of HMI. In this regard three phases of information processing exist.

The first phase is given by early processes including information perception. The perceived information is further processed by central cognition processes; before it becomes translated into a motoric reaction during the phase of late processes [ 6 ]. To support the machine operator within these processes, information is to be organized that perception, speed and ease of comprehension is optimized to guarantee that the operator perceives essential information and is able to intuitively translate decisions into actions [ 7 ].

Following this approach, information corresponding to human mental models can be processed easiest. However, current navigation structures of machine tool interfaces are structured function-oriented, whereas human mental models tend to be task-oriented [ 8 ]. Therefore the function-oriented model must be transferred into a task-oriented model for every single operation.

Designing an interface with a task-oriented navigation structure, would be more suitable to mental operating models, reducing mental strain. In addition, the software of current HMIs has been mapping the ever-increasing machine complexity, leading to depth and complex hierarchical navigation structures [ 9 ]. To study these effects, we investigated a preliminary laboratory study in prior research that showed effects of task-oriented HMI design on performance and errors [ 10 ].

Based on these findings, we implemented a field study to test results in real working conditions. Using the example of a cutting machine, the human-machine interface was analyzed. Regarding to ergonomic requirements we formulated design recommendations according to task-orientation. On this basis a software prototype for cutting machine interfaces was developed. This paper deals with a field and a laboratory control investigation, evaluating the prototype according to relevant usability objectives for software dialogues [ 11 ].

The main objective was to test the task-oriented HMI prototype compared to the actually used function-oriented HMI. Therefore usability was tested for both versions with the IsoMetrics S questionnaire [ 12 ], based on Standard DIN EN ISO [ 11 ]. We concentrated on a single workflow that did not imply any tasks, which neither demanded individual adaption of the GUI nor triggered error situations.

Thus, we eliminated these dimensions from the questionnaire. Results for each objective were analyzed by mean and standard deviation and compared within the two HMI software versions. Furthermore we tested subjective mental strain with the Rating Scale of Mental Effort RSME [ 13 ]. Thereby lower levels of subjective mental strain implicate a better support of the human-machine interaction, and thus indicate a better usability. Participants were shown the RSME scale after each condition and we asked to answer their stress experience spontaneously.

The study was divided into two parts, a field study in a cutting machine company, and a laboratory study as reference group. For the field study 8 participants aged between 26 and 65 years with an average age of Seven of the tested participants were male, only one participant was female.

The same number of persons participated in the laboratory study. In this study the average age of participants was All participants in the field study were employees of the cutting machine company and therefore had good knowledge on cutting machines and software on average. Participants that were tested in the laboratory on the other hand predominantly had neither good knowledge in cutting machines nor in the implemented software.

One part of the study was conducted in a company of a cutting machine manufacturer. Both software versions were installed and tested on an HMI of a cutting machine. After a short introduction and a questionnaire for demographic questions, all participants completed the task with both software versions in alternating order. They were given a step-by-step instruction of the workflow, without any further details, to test the interface according to its usability.

The other part of the study was conducted in a laboratory of the Institute of Industrial Engineering and Ergonomics RWTH Aachen University under the same conditions, as a controlling condition with a more standardized study environment. In this case we used the same software versions and participants had to complete the same workflow with both software versions on a computer representing the HMI. In this part of the study, we did not connect a machine tool to the interface.

Thus, participants were given a verbal and picture-based introduction to the scenario. The task to fulfil was the workflow for cutting a foam block manually see Fig. Mean of RSME values when using actual software version and prototype in laboratory and field study. Qualitative assessment of both software versions in field and laboratory study. However, we could not prove significant time differences between the software versions. Results of the field study show that both software versions meet usability objectives exclusively with values above the mean 3 on the five point scale applied for the questionnaire.

Based on this, results for the prototype usability are more consistent over all participants. This allows a more reliable interpretation, also indicating potential for more efficient process scheduling in production planning by means of task-oriented machine tool HMIs. For both dimensions participants rated the actual software version only with 1 of 5 points on average. According to correspondence with the tested usability objective the value is equivalent to disagreement.

The prototype version on the other hand, was rated with higher values above mean regarding these objectives. However, findings for task suitability, self-descriptiveness and controllability are less conclusive. For these usability objectives no change can be observed. Regarding the purpose for the same task of both software versions, it seems appropriate, that quantitative results for task suitability are similar. The value was near average of 3 for both versions.

Self-descriptiveness is an indication for intuitive software handling, which becomes especially obvious for novices, who are dependent on self-descriptiveness, if they are not further assisted. The fact that all laboratory participants were novices, who were indifferent about the quality of self-descriptiveness of the prototype with no difference to the actual software version, clearly shows the ergonomic potential that is not exploited yet.

In addition, controllability principally requires system knowledge, as well as understanding of tasks, processes and consequences. Hence, lack of experience with machine tool interfaces, and thus a missing mental model of controlling operations can be regarded as reasonable to explain the findings. The assumption about a lack of expertise of persons attending the lab study becomes more probable according to this observed little deviation from the mean.

As controllability was rated nearly equal for both software versions, participants seem to have experienced similar challenges interacting with, respectively controlling both systems. Inappropriate mental models definitely contain potential to positively influence the discussed effect, since it is the most dominant common factor within the group, though unproven yet. To concern the probable correlation, and to validate this hypothesis, future studies are required.

In contrast to the questionnaire results for usability objectives, we found a clearer qualitative evaluation in the interview results. Using the prototype version was perceived as easier and more intuitive, furthermore this version was perceived as clearlier arranged by more than half of all participants, even in the field study, where differences did not show up between both software versions.

Results of the subjective cognitive load do not differ between both software versions, what could be originated in the standardized workflow task with short term subtasks that do not lead to high strain levels independent of the implemented software. Obviously knowledge about cutting machines and software has an influence on subjective mental strain, because novices had a higher subjective cognitive load than experienced participants for both software versions.

The main limitation of the study is the small sample size of 8 resulting from the effort of conducting the study during business hours in the machine hall and therefore limited access to employees. To better compare results, we tested the same number of persons in the laboratory study, which leads to unclear finding, difficult to interpret. This paper deals with a field study about usability of task-oriented cutting machine HMIs.

Prior research has already shown the benefit of task-oriented human-machine interfaces for a more intuitive interaction by reducing complexity and supporting human mental models [ 1 ]. However, these works did not study the influence of task-orientation on usability objectives. A better usability is one factor that can improve strain level by providing less stress while interacting with the system itself.

After our findings in the explorative preliminary study, this study can be seen as a pursuing study built upon our explorative preliminary study [ 11 ] to gain first important findings of the impact of task-oriented HMI design on usability objectives in real working conditions. In this study we tested effects among two groups of participants. Participants in the field study were employees, familiar with the current software, whereas participants in the lab study were novices.

The results of the IsoMetrics S revealed that task-oriented HMI did not have an effect for skilled workers, who are accustomed to the actual software, since none of the usability objectives showed an improvement for the prototype compared to the actual version. Longtime trained mental models for the actual software version could be seen as an explanation. The findings are different, however, when regarding the novices. Regarding results for the standard deviation, however, results were spread more evenly for both groups for the prototype version, confirming the quality of the discussed results.

Nevertheless, results mostly valued above mean by three points rating and still reveal potential for improvement for the prototype version. This should be considered for future work.

Advances in Neuroergonomics and Cognitive Engineering pp Cite as. The following article presents an approach on the extension of WorkDesigner—a simulation-based software tool for the strain-based staffing in industrial manufacturing—for the prospective design of IT work places. After a short introduction of WorkDesigner, the common economical and technical need for the individual design of IT work places is described in the following chapters.

Here the current mega trend Digital Transformation takes center stage. Finally, the results and the future developments are discussed. Digital Transformation, Internet of Things or Industry 4. This crosslinking has the potential to release enormous power of innovation.

A high level of flexibility and speed of the IT is demanded for the long-term assurance of profitability and competitiveness. Common IT approaches can not sufficiently guide the processes of the digital transformation. A change of the IT paradigm is needed to enable application- and user-specific work modes cf.

In this context a field study by System Concepts LTD. Impressions of WorkDesigner cf. It is important to note that in this approach employees and work places are the main parameters. Every work place is defined by five parameters stress factors rated from excellent to deficient : lighting, climate, noise, work posture and work intensity. In the following chapters the common economical and technical need for action is described as well as an approach on the extension of WorkDesigner for the prospective design of IT work places is drafted.

The Digital Transformation has become the ultimate challenge for almost all industries. The use of technology to radically improve performance, enhance the customer engagement and create new digital business models is the overall task and a substantial challenge for the IT organization.

In the past the IT departments focused mainly on supporting the business by offering the needed technical capabilities for highly optimized processes. Running a stable and reliable infrastructure and offering adequate services were the primary focus.

A sufficient business and IT alignment was the goal. This has changed radically through the Digital Transformation. Suddenly the digital services are a substantial part of the offering. The requests towards the IT are no longer coming from the internal organization, but from the external market and the customer itself.

Not stability but agility and speed are the critical capabilities of today. To be directly involved in the product design, the development process and the digital service offering is a new situation for the IT department and causes sustainable discomfort. Through the enormous pressure the most IT departments do not see the great chances they have been given by moving into the strategic center of the core business. The shift from product orientated business models towards service focused business models will make the IT a substantial part of the value chain itself.

The integration of digital services will not only have a tremendous impact on the IT department but on almost all areas of a company. The number and the complexity of IT workplaces will grow dramatically in the next years, and at the same time the flexibility of the workplace infrastructure will change as well. Flexible and mobile workplace concepts within the company and outside must be supported.

The integration of smartphones and tablets will take place and will have a tremendous impact. A seamless IT infrastructure, optimized towards the needs of the operational procedures will be substantial for the overall success of a company. Through the Digital Transformation and the new role the IT will take in the near future, the ergonomic aspects of IT workplaces will become a critical success factor for companies.

Many different influences impair the achievement of great software. Some programs are more compelling to increase or decrease the user efficiency than others. The quality of software should not only be selected by the visual appeal of the graphical user interface but more influenced by the quality of the programming of the core object model.

Hidden influences of usage quality cf. There are principles of software development placed in norms like ISO which the subject matter is the Ergonomics of human-system interaction, including dialog principles cf. There is also a standard about the forms cf.

The general purpose is to recommend how the software structure be realized. It can be comprehended that parts of the ISO as well as elaborations cf. According to the ISOthe software should maintain the specifications of each part to reach this characteristic. There are some known basic approaches such as grouping similar information to receive clarity cf.

But it is quite surprising these standards should be considered as the publication date is more than ten years since its original publication. This is an inherent problem of the ISO Most parts are just too old for the extremely fast rising and especially changing information technology sector. The flow of the user dialog today is an example, which is not comparable to the entire principles of cf. Especially when considering the entire domain of connected devices. Furthermore, there is a considerable number of specifications that in some cases concern an overstated level of detail, as well as most specifications, are still not entirely regulated.

Fortunately, there are no regulations that dictate how to design a Button cf. A significant problem is the neglecting of user groups. Different knowledge of users can affect the software-usability and acceptability in a strong way. A well developed user-adaptable software program can generate a high efficiency because it is providing the user new skills and knowledge in an optimal way.

Only fundamental characteristics can be inferred from the literature. Today, great software design means not only to accommodate user skills; it also means the adjustment to lifestyle. This implies self-adaption to the software via exterior influences. A nice example of the difference between the dialog principles is Google Glass. Depending on the location and view, Google Glass displays necessary information through an augmented reality interface.

To achieve optimal usage, the software would be required to adapt to any hardware device. There is not one correct way and always best software design; the designer needs to differentiate the product to reach the optimum level of characteristics and general acceptance in any and all situations.

As it has been shown in the previous chapters, the impact of IT is increasing. More and more workplaces are turning into mobile offices, which enables employees to work from anywhere. As result of this, their ergonomic requirements are changing as well. Accordingly, the simulation-based software tool WorkDesigner is proposed to be adapted. Based on the considerations of the previous chapters, the following part gives an approach on how the software should be expanded.

Most of the common simulation systems are lost in the detail. For companies which want a quick result this is not practical. So additional parameters therefore have to be evaluated quickly, either in a subjective or an objective way. The parameters for age and gender are already used in WorkDesigner and now added to this are nationality, area of expertise and a few questions about the personal behavior with software. So the fact that different cultures have different ways of reading and writing are included in this point.

All of these could be evaluated quickly on a scale of one to six. According to Florin [ 14 ], who explained that usability and design have to be clearly divided, the four parameters are split into these two categories. The first impression of software. This contains the optic and presentation for the user. Are objects arranged in a proper way? Do I have all important tools on the first page? These are just a few questions which give a personal impression of the Software and represent a subjective way to evaluate this point.

To evaluate the software more objectively, the DIN EN ISO should be used. The DIN gives a huge number of criteria as to how objects have to be arranged and how much information should be given. In addition to that, the knowledge about human nature, as for example Florin [ 14 ] explained it, can be important. Apart from the Setup one important aspect of Software is the possibility of sharing data with other programs. This connection is the API.

Most workplaces are working with more than one type of Software, so it is important to have good a connection between all programs. How well this works and if all programs are involved is a good way to evaluate this point. Also the possibility to share between different operating systems, like iOS and Windows, has to be in focus.

In contrast to Setup it is difficult to evaluate the API in an objective way. The first parameter which deals with usability. In Landauer [ 2 ] already described that with the right software, you could raise your productivity to nearly percent. In addition to Landauer [ 2 ] the System Concepts LTD.

Reference [ 3 ] figured out that the important part of software working well is the matching between software dialog and work processes. It is therefore important that you can fit the software to your personal requirements. How many different changes can you do? Can you change the design and can you create own software add-ons? These questions could help to evaluate the software more objectively.

As Reiterer and Geyer [ 15 ] describe, usability transforms more and more into the user experience so it is important to take a look at this. So the last suggested parameter is handling which describes the user experience and feelings while working with software. Experiences like: How fast can I work with the software? How much help did I get and also how consistent are the different parts of the software? All of this creates the impression of the work and has an influence on the level of stress.