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Authors: Barbara Hinz, Gerhard Menzel, Helmut Seidel, Ralph Blüthner Keywords: whole-body vibration, seat transmissibility, SEAT, frequency weighting, individual variability, anthropometry Summary: An experimental study was
performed in order to examine the influence of the
exposure conditions, different postures and the seat type used by the analysis of
variance.
On the variability of the impedance
depending on the intensity, posture and body Authors: Barbara Hinz, Helmut Seidel, Gerhard Menzel, Ralph Blüthner Keywords: whole body vibration, impedance, nonlinearity, intensity posture, individual variability Summary: Design and model
development for workplaces with exposures to whole body
vibration are often based on mean values of the impedance of the sitting man presupposing
his
linearity. The influence of intensity, posture and body mass on the impedance and its
variability
were investigated in an experimental study. The mean values of the impedance agreed
generally
with the results of other authors and the state of the art as presented in standards. But,
the
mean values describe a system with a damping that is higher than that of the individual
cases.
Analysis of lane changing manoeuvres in road traffic (Vol. 1/2001) Authors: Wolfgang Fastenmeier, Jürgen Hinderer, Ulf Lehnig, Herbert Gstalter Keywords: Characteristics of lane changing manoeuvres, Driver assistance system, Traffic and driver situation, time-to-collision, Critical gaps Summary: One possible application of
new in-car information and assistance systems is to
support the drivers' lane changing manoeuvres, which could contribute to an increase in
road
traffic safety. First of all, the basic requirement for the development of such a complex
functionality is to analyze and specify prerequisites that have to be fulfilled as far as
road traffic
conditions, car technology and systems technology are concerned. In this contribution,
relevant
characteristics of lane changing manoeuvres and their safety criticality are analyzed and
related
to an in-vehicle system addressing lane changes. For this purpose a classification system
for
lane changing manoeuvres was developed and applied in a field study on highways, rural
roads
and inner-city traffic.
Support of design thinking (Vol. 1/2001) Authors: Pierre Sachse, Sven Leinert, Winfried Hacker Keywords: Design problem solving, Engineering design, Sketching, Computer aided design, Virtual reality Summary: This study analyses the
possibilities of external assistance of the demanding cognitive
activities in engineering design. The main interest was the interrelationships between
mental
problem-solving on the one hand and sketching and other types of prototyping (CAD, Virtual
Reality) on the other. It is shown that an additional sketching support can lead to a
reduction
of working steps. Mainly repetition-, rejection- and test- steps are reduced by sketching.
The Experience of Job Ambiguity by Temporary Employees (Vol. 1/2001) Authors: Daniel Sodenkamp, Klaus-Helmut Schmidt Keywords: temporary work, facets of job ambiguity, information policy, performance feedback, job satisfaction, group cohesiveness Summary: The present study focusses on the degree of experienced role ambiguity of temporary employees in comparison with regularly employed coworkers. The distinction of three facets of role ambiguity refers to the experienced uncertainty about the work methods to be used, the uncertainty about how to schedule the work, and the uncertainty about the performance criteria to be met. One key finding of the study is that temporary employees experience significantly more ambiguity throughout all facets than their coworkers. To investigate whether these differences related to the status of employment, hierarchical regression analyses were performed. The consideration of some biographical data and - among others - some feedback and satisfaction variables served to control for the influence of possible third factor variables. The results suggest that differences in perceived role ambiguity do not result from status of employment. To a certain degree they pursue correlates of status of employment.
Diagnosticity and sensitivity of instruments for strain meaasurements (Vol. 1/2001) Author: Martin Schütte Keywords: Diagnosticity, sensitivity, effort-scale, AGARD-Stres-Battery, generalizability theorie Summary: For the determination of
mental workload questionnaires have been proved to be
suc-cessful. However, the selection of a method adequate for the application to a special
case
is difficult, as there is a lack of information concerning the range of employment of the
various
methods. Nevertheless, two new criteria facilitating the choice of an appro-priate
instrument exist - namely diagnosticity and sensitivity. A procedure can be
considered as diagnostic
if it
is able to discern different types of workload. Furthermore, a method fulfills the
criterion of
sensitivity if it can distinguish differences in levels of load imposed on an operator. In
the
present study both characteristics were determined exemplary for the so-called
effort-scale.
Emotion and work: The state of the art (Vol. 1/2001) Author: Jürgen Wegge Keywords: emotion, mood, work motivation, work satisfaction, emotion management Summary: Work gives the opportunity
to experience many different emotions, e.g. boredom
or interest in work activities, shame or pride about ones own achievements or love, anger,
jealousy, gratefulness and hate as regards colleagues, clients, patients and supervisors.
How
specific emotions and moods are caused at work and to what effects this can lead has been
extensively examined in recent years. Based on this new evidence, it can be concluded that
a
precise analysis of emotions and moods at work has many advantages. For example,
phenomena such as helping behavior, fluctuation and change of achievement can be explained
much better than with classic emotion or motivation indicators (e.g. work satisfaction). Seamless integration of virtual reality in habitual workplaces (Vol. 2/2001) Authors: Oliver Bimber, L. Miguel Encarnação and André Stork Keywords: Virtual Reality, Augmented Reality, User-Interaction, Next-Generation Workplace Summary: Employing virtual reality (VR) technology, computer-based work environments are clearly evolving into a major component of the next-generation workplace. Over the past few years, VR has become a practical reality for many applications, thanks to a number of technology inventions. In this article, we introduce ideas, proposed technologies, and initial results for a seamless integration of virtual reality in habitual workspaces, thus successively transforming them into efficient, high-tech work environments.
Learning Oriented Design for Ease of Use of Technical Systems (Vol. 2/2001) Author: Georg Geiser Keywords: Learning and using, learning objectives, learning preconditions, learning oriented design Summary: Action competence acquired by preparatory and accompanying learning is necessary for successful use of technical devices. Therefore, user-oriented design of this learning process is essential for the objective of ease of use. First learning for human-system interaction is analysed in view of learning objectives, content and access. Then learning conditions are discussed which show different aspects for the design of learning processes regarding technical and human prerequisites. On this basis a procedure for learner-friendly design of technical systems is proposed. Furthermore, design principles are outlined allowing learning effort to be adapted by users to their needs, especially to their different objectives, contents and scopes of learning.
New User Interfaces for the Support of Work- and Leisure Communities (Vol. 2/2001) Authors: Michael Koch, Dave Snowdon and Antonietta Grasso Keywords: information systems, knowledge management, community support, user interfaces Summary: The usage of computers for
supporting work groups and communities in work and
leisure settings reaches its limits when it is important to get a large coverage without
explicit
organisational sanctions. A possible solution to the problem is to extend the coverage
using
new user interfaces.
Visualisation as
Communication Interface: The Role of Pictures for Organisational Author: Kathrin M. Möslein Keywords: visualisation, visual
communication, mapping, organisational change
Summary: Looking at the development of new media, today numerous scientists of quite
different disciplines are realising a "visual revolution" and a changing balance
between pictures
and words in human communication. These fundamental changes towards visualisation at the
human communication interface are of major importance for organisations: for learning
processes, knowledge creation and knowledge management, for co-ordination processes in
distributed organisation structures and for future development trends of organisations and
societies as a whole.
Designing user interfaces as
an ergonomic procedure supported by Software Tools Authors: Hartmut Wandke, Richard
Oed, Eduard Metzker, Markus van Ballegooy and Keywords: user interface, assistant systems, usability, design process SUMMARY: In a project called
"Electronic Multimedial Operation and Services Assistance"
(German acronym: EMBASSI) are software-tools developed that are based on intranet
technology. This project is funded within a national research programme on Human-Machine
Interaction in Knowledge Society by the German Ministry of Higher Education and Research.
View Concept for the
ergonomic visualisation of object-oriented enterprise data Authors: Gert Zülch, Sasche Stowasser and Volker Keller Keywords: Communication ergonomics, user friendliness, user interfaces, object-orientation, evaluation Summary: The aim of a project of the Collaborative Research Centre 346 "Computer-Integrated Design and Manufacturing of Parts" was to create a clear representation of complex object-oriented data structures and to reduce the resulting information flood for the user. Based on experimental investigations communication ergonomic user interfaces for handling, navigation and editing of object-oriented information have been developed. To compare different forms of representation eye mark recording, key stroke recording and observation of the test persons were used. The investigation was structured in two parts. The first part concerned the structuring of data representation with the result, that an extensive visualisation of all information not favourable is. In the second part a multi-dimensional form of representation was compared with a window technique. It can be concluded, that a three-dimensional visualisation could have advantages over traditional visualisations. Spinal load in specific carrying tasks (Volume 3/2001) Authors: Claus Jordan, Matthias Jäger, Andreas Theilmeier, Alwin Luttmann Keywords: Carrying, lumbar load, biomechanics, ground reaction forces, inertial effects Summary: The aim of the
investigation is the determination of characteristic values of the
lumbar load when carrying objects on the shoulder and in front of the body. With the help
of a force plate integrated into a gangway, the ground reaction forces for both carrying
types
were measured. Each case was executed with different load weights and different walking
velocities. The obtained data were used for biomechanical model calculations for
quantifying
characteristic values of load on the lumbar spine, considering the inertial effects
determined
when carrying a load (in contrast to static holding). The results of these calculations
clearly
show a dependency of the compression force on the intervertebral disc L5-S1 - as one of
the
most important characteristics of lumbar load - on object weight and walking velocity.
Simulation of the compressive forces
in the joints of the legs and the spine under Author: Martin Fritz Keywords: Compressive forces, model, whole-body vibration, transfer functions Summary: Under vibration stress the
compressive forces transmitted in the joints of a standing
or sitting operator are composed of nearly static and oscillating force parts. Because
these
forces can hardly be measured a biomechanical model was developed to simulate the forces.
The concept "stress and
strain" compared to other concepts in the field of work Author: Rainer Oestereich Keywords: complaints, decision
latitude, health, psychological demands, strain, stress, Summary: The concept "Stress
and Strain" (Belastungs-Beanspruchungskonzept) was
originally developed with regard to stressors associated with physiological strain. Later
on the
concept was extended to the social sciences; it is asserted that the model is also valid
for
psychological stress. Several other concepts in the field of work psychology deal at
length
with psychological stress, but they are, in overall, inconsistent with the conception of
stress in
the "Stress and Strain" tradition. Four psychological concepts are described:
the "Demand/Control- Model", "Complete Activity" (Vollständige
Tätigkeit) "Stress at the
Workplace" (Stress am Arbeitsplatz) and "Requirement/Stress"
(Anforderung/Belastung).
Entry into the world of work -
unmet, met and exceeded expectations Authors: Nathalie Galais, Klaus Moser Keywords: unmet expectations, positive surprises, optimism, apprentices Summary: Newcomers have various
expectations when entering the world of work. These
expectations can be met, unmet or exceeded. In the present study with 175 apprentices
(mainly working in the financial services sector) we investigated the impact of the
various kinds
of fulfilment of expectations on job satisfaction and intention to leave. In addition,
determinants
of the degree of fulfilment were analysed.
Looking back into the future of ergonomics (Volume 3/2001) Authors: Friedrich Fürstenberg Keywords: crisis of work-oriented society, core definition of ergonomics, participative rationalisation, research logic, research organisation, research strategy Summary: Based upon a historical survey, basic orientations of ergonomic research are mapped out, demonstrating the need for interdisciplinary cooperation. With growing interest in participative rationalization limits for socio-psychical demands become additional research topics. Recent fundamental changes in work structures and processes challenge ergonomic self-assessment. Generation, communication and application of research findings need creative anticipation.
Designing the human/machine interface in chemical plant planning processes: Safety requirements and findings of an empirical study (Vol. 4/2001) Authors: Brigitte Beer, Peter Stadler Keywords: Occupational safety in planning processes, Human/machine interface in plant planning, preventive work design Summary: Occupational safety in the chemical industry requires preventive design of the human/machine interface when the plant is being planned. This involves an anticipatory analysis of the future working tasks and the psychological processes (by way of perception, assessment and decision) which are necessary for plant safety. Objects of planning with regard to safety are function sharing between operator and process control system and the tailoring of both the working tasks and the information and instruction input system. The article presents first research results on ergonomics and occupational psychology with respect to safe behavior in chemical plants. It then shows findings of an empirical study analysing the design of the human/machine interface in 10 chemical planning processes. It is shown that planning processes differ above all in terms of the philosophy of automation and the assessment of human reliability. Planning processes were suboptimal in terms of the design of working material, qualification and participation when they took only the technical aspects into consideration and failed to see the operators as a resource for comprehensive safety. Deficits and improvement potentials are discussed on the basis of these results. Focusing the perspective of the operators appears to be essential to planning processes because the operators are much more critical of the safety of new plant than the planning engineers.
Towards the validation of multi-dimensional handbooks for usability engineering – The EU-CON II case (Vol. 4/2001) Authors: Christian Stary, Thomas Hahn, Roland Hintersteiner, Klaus Schatz, Alexandra Totter Keywords: Usability Engineering, validation of handbooks, (re-)design of user interfaces, evaluation and engineering of VDU-work, occupational health and safety, EU-Directive 90/270/EEC Summary: Usability engineering targets towards human-oriented design and evaluation of interactive software systems. Traditionally, there is a gap between the design and evaluation process. The respective techniques are neither synchronized nor do they deal with the same set of items for design and evaluation. In particular, design activities are focused on transforming the results from analysis to specifications for coding, whereas usability testing is based on principles of software ergonomics, such as task conformance. In addition, usability engineering techniques focus on particular aspects of interaction, such as technology or organisation of work, rather than a balanced mix of those aspects. However, in the design and evaluation of interactive computer systems, developers must understand what causes some interactions to be seen as good, productive, and useful, and what causes others to fail. Thus, they need an explanatory and causal understanding of human-computer interaction throughout the different phases along development, differentiating the technological, cognitive and organisational aspects, as well as their mutual relationships. Techniques for user-interface design as well as interface evaluation have to take into account the fact that interaction between people and computers occur in many and varied contexts and situations even in occupational settings for a given set of tasks, with many and varied forms of interaction styles and devices. Having this picture in mind, the EU-CON (EU-CONform evaluation and engineering of VDU-work) techniques has been developed, in order to implement the EU-directive 90/270/EEC on human-computer interaction accordingly. The directive requires organisations to ensure a minimal usability standard of interactive software systems at workplaces equipped with Visual Display Units (VDUs). Hence, a proper solution had to focus on checking and improving the (use of) software in the course of individual task accomplishment at the work place. EU-CON relies on a variety of components, such as guidelines or data acquisition methods, and addresses two distinct phases of development, namely evaluation and redesign. The latter is required, in order to actually improve individual workplaces, once trouble has been experienced. In contrast to most other techniques, EU-CON II does not only take into account for operational definitions the different aspects on VDU work (as mentioned above), but also provides a practical interface between evaluation and redesign. Hence, the results of checking the usability of a software at a certain workplace might directly lead to actions for improving occupational health and safety with respect to the use of the checked software. The application of EU-CON II should lead to reliable results in an effective and efficient way. Hence, each component of that technique has to be checked for effectiveness and efficiency. This paper deals with checking the intelligibility and accuracy of the hand book of EU-CON II. Since EU-CON II has been developed to enable the evaluation and corresponding redesign of user interfaces with respect to user needs and task requirements, both major parts of the instrument, i.e. the questionnaire as well as the handbook, has undergone empirical tests. In particular, the guide for usability-data acquisition as well as the handbook for evaluation and (re)design had to be tuned for a smooth transition from (task and user) analysis to (user interface) design. Since this transition has been of major interest, the user-specific problem diagnosis based on the acquisition of data and the subsequent development of suggestions for improvements either with respect to the organization of work, user skills, and/or technology had to be tested. Methodologically, we followed the rules of complete double analyses along two steps: In the initial step the checklist for reporting troubles has been checked for intelligibility through evaluators. Problems have been recorded and analysed systematically. In the second step of the study the usability of the information provided for identifying causalities and coming up with proposals to modify troublesome components or situations have been checked. Based on these results the hand book is currently redesigned. The results can be used in two ways: Firstly, the method that has been developed for testing the EU-CON II handbook can be used for any manual that guides domain experts through a development evaluation procedure. Secondly, the results indicate that the utmost benefit for users of software can be achieved when the users participate in the development and usage from the very beginning. In case of usability engineering, it means to qualify (potential) users to provide the developers with an individual description of the work domain, in order to provide a proper universe of discourse for evaluation and redesign. It is then the developers task to use the aspect-related procedures of the handbook to come up with proper suggestions for design or improving and the work conditions, respectively.
Interruptions and troubles with regard to the self- and familiy-regulation in the integrated work-familiy-system of telework (Vol. 4/2001) Author: Michael Treier Keywords: integrated work-family-system of telework, self- and family-regulation, interruptions and troubles, stress and coping Summary: This article represents central results of a study which deals with aspects of the self- and family-regulation to find out essential moments of stress and strain in the integrated work-family-system of telework. Referring to this it is important to consider not only classical aspects of the work design but also the processes of social or family-regulation. The troubles and/or interruptions during the job are represented and discussed here in particular. Telework isn’t a trade or a profession or a job, it is just a way of doing work: "People can work everywhere and at any time" (freely to Gil Gordon, pioneer of teleworking). This means both a good one and a bad news concerning teleworking and manifests the "Janus face" which stamps the entire discourse around teleworking respectively telecommuting. Light and shadow play a confusing and engaging game of light, that hinders and complicates an objective attitude on this vivid topic and ever changing and growing phenomenon behind. The arising enthusiastic atmosphere concentrates on the advantages disregarding the obstacles and problems or even dangers of teleworking. Limits and constraints are often ignored with respect to interest-driven standpoints. Aspects focusing economics or labourpolitics prevail frequently and thus veil the horizon of creative development of teleworking opportunities and diminish the putting through and success of holistic improvements or solutions for special problems regarding the integration of family and work. This analysis does not follow the characteristic conduct and proceeding concerning the strategies of investigation in connection with the informatization and the increasing extent of flexibility of the work field. Their studies emphasize potentials and expectations or future speculations on teleworking with regard to the global trend to the dominance of information and communication technology at the workplace. A more balanced view must not ignore the special workload experienced by the practitioners of teleworking, however. This applies especially to the so-called "isolated telework" or home working as the purest type of teleworking. Self- and family-regulation seem to be the most demanding challenge in this context. Close to the typical workplace and its processes the given situation and its bandwidth are explored with the help of thorough interviews with teleworkers and observations concerning the actual practice of teleworking in order to find out important aspects of stress and strain. Special attention is given to a compatible arrangement of working and living conditions within the family. The family as a given entity of the teleworking context is too often reduced and abused as a factor of disturbance which is to be avoided. Far from it this study detects and describes family as a productive and regulatory factor of teleworking and thus as an integral part and asset of successful teleworking. Studies neglecting the family tend to socialize the positive side-effects of its presence, but at the same time privatize conflicts and frictions which are also due to the close relation of work and family in the teleworking sphere. And these one-sided studies leave their fingerprint on practitioners such as workplace-designers who reduce their ambitions more or less to the ergonomic factors and only accept the information and communication technology as an enlargement of their design tools. The reality of humankind requires a more complex and proactive view on the teleworking place: Psycho-mental and psycho-social loads indicate the interdependence of family-health and work-fitness. Family management itself is influenced by the interrelated correspondence of a workplace within the family and family as an integral part of the workflow-processes. Family should not be evaluated as an invisible place for recreation points. It is neither this refugium nor an assimilated back office of the telework-place, but an integral and integrated part of telework and its output. The hiatus between family and workplace is not easily bridged and this is a conflict especially for the female teleworker. Synchronization and alignment of child care and work duties are a permanent endeavour which tackles the question of co-operation between two working spheres within one sole person. Congruity between work and family life as a myth will never be overcome by reality if regulatory processes between family and working conditions are constantly ignored. The study aims to concretize stress and strain moments during the home working taking regulatory processes and family circumstances into account, because changes without paying attention to these aspects last-mentioned are partly unfounded.
Support value of sketching in the design process (Vol 4/2001) Authors: Martina Schütze, Pierre Sachse, Anne Römer Keywords: design problem solving, process of sketching Summary: Engineering design as a demanding and complex thinking activity in terms of creative design problem solving has been the subject of interdisciplinary research of psychologists and design engineers for several years. In the center of the research interest primarily lies the registration of thinking and action processes during engineering design and the search for specific support possibilities of the design process to meet increasing requirements of product development. Of central importance for design results are the early stages of problem finding, problem analysis and conceptual design, in which 70 to 80 percent of production costs are determined (Ehrlenspiel 1995; Ulich 1998). Since in this stage the error correction possibilities are the highest, the use of low expenditure sketches and material models during design is crucial. While research on design problem-solving up to now often focuses on the use of external support forms, there are few findings about the support value of sketching and modeling as a process. In this study the support value of sketching activity in the early stages of the design process is discussed and checked experimentally. In particular the process of sketching which includes the activity of external, observable sketching and using the sketch at the same time is in the focus of attention. This knowledge is of central importance for selecting and arranging the support for the design engineer during designing and for an explanation of the support effects. In a laboratory experimental study sketching activity and the use of sketches were gradually limited. The influence of three experimental conditions, which differ in the demand to sketch and the time to use the sketch, was tested using the t-test for independant samples. The first two groups were requested to sketch either temporarily unlimited (completely supported design) or up to a certain degree of completion of the constructive solution, when both the sketch(es) and the possibility for further sketching were withdrawn from the subject (partly supported design). Under the third condition there was an explicit demand not to sketch so that only a mental treatment of the constructive solution took place. The sample was composed of 45 (3 female, 42 male; average age 24 years) students of the mechanical engineering graduate program at the TU Dresden. There were no significant differences in spatial ability or motivation for the treatment of the task. The subjects were asked to work out a commission for a garden grill up to the concept stage without time limitation. The grill had to meet certain fixed demands. The difficulty of the structure of requirements was classified as medium using a procedure for theoretical problem and task analysis (Schroda 2000; cf. Beitz, Hacker & Timpe 1997). Dependent variables including the quality of the solution, total solving time, subjective experienced difficulty of the construction task, and subjective sureness regarding the correctness of the solution were recorded. Regarding the quality of the produced solutions, significant differences between the conditions were shown. The constructive results of entirely supported subjects showed a significantly higher solution quality than those of both other groups. Furthermore, the solution quality of partly-sketching subjects could be classified as significantly higher compared to that of subjects who treated the problem entirely mentally. Regarding total solving time, entirely supported subjects needed significantly more time working out the constructive solution than subjects treating the task mentally and those who had only limited sketching time. Partly supported designers differed insignificantly with regard to total solving time from those who carried out the task without external support. Subjects with temporarily unlimited sketching possibilities and use of sketches rated the task to be significantly less difficult compared to subjects who treated the task entirely mentally and those, where both the sketch(es) and the possibility for further sketching were withdrawn at a certain point in the design process. Subjects of the revocation condition and entirely mental problem solvers differed not significantly with regard to the subjective experienced task difficulty. No significant differences could be found between test conditions regarding the subjective sureness of the correctness of the solutions. The progress of time, the activity shares and the changes of the performed activities when elaborating a constructive solution as well as the procedure of sketching were regarded more closely at a selected example. There a periodical change between internal, mental and external, materializing activities could be observed. Findings regarding the signification of sketching confirm the importance of the development of digital sketching tools. Through their hard and software ergonomic concept these can open a large potential regarding time and cost saving for computer aided design in mechanical engineering. Experimental studies about the support value of digital sketching media, which are to allow intuitive work similar to traditional sketching, are not yet available.
Quality ensuring through self-evaluation: Application of the "participative productivity management"-approach in psychiatric hospital (Vol. 4/2001) Authors: Sven Hollmann, Klaus-Helmut Schmidt, Ulrich Trenckmann Keywords: quality management, self evaluation, hospital, productivity measurement Summary: Attempts for quality ensuring in public health in general and in the psychiatric practice in particular are confronted with a number of problems relating to the measurement and evaluation of performance. With the ‘Participative Productivity Management’ (PPM) a new method is introduced that promises to solve some of these problems. PPM guides teams to develop their own performance measurement and evaluation systems as a basis for creating team-related feedback information. Each group develops its own system with the help of an external moderator in three steps: First, the work tasks, the group has to perform, are defined, second, indicators are made up that measure the quality of the performance for each work task, and third, the contribution of each indicator to the overall quality of the work group is described with the help of performance-evaluation-functions. The development of the system, especially the resulting performance indicators follows the criteria of completeness and controllability and is done in co-operation with clients, the management of the organisation, and other relevant external performance evaluators. The application of PPM as a pilot testing on two wards of a psychiatric hospital shows that the quality of psychiatric services can be measured and influenced as well. The method enabled the multiprofessional teams to direct their activities on commonly agreed quality criteria and to optimise their work through a process of self-organisation. After the successful testing now some more wards shall develop their own systems with the help of trained internal PPM-moderators. |