This thesis presents experimental studies on the relationship between external surface pressure and the perceived discomfort in seated body areas, in particular those under the ischial tuberosity and the mid-thigh. It consists of three parts. Part one provides a comprehensive review of the existing knowledge concerning seated discomfort. The current assessment methods of seated discomfort are summarised, with the emphasis on the validity and reliability of the rating scale methods. The implications of surface pressure to seated people are outlined from the perspective of clinical, sensory and perceptual, and ergonomics domains. A brief review of current technologies for pressure measurement is also provided. Part two presents the experimental work. It starts with an exploratory assessment model of seated discomfort, based on pressure measures. Two preliminary experiments were conducted to test the feasibility of the model. Three further psychophysical experiments were carried out to test the validity and reliability of the selected six rating scales, and to investigate the effects of surface pressure levels on perceived pressure intensity and discomfort in the seated mid-thigh and ischial tuberosity areas. Surface pressure stimuli were applied to a seated body area of 3,318 mm2• Subjects judged three items of sensations: pressure intensity, local discomfort, and the overall discomfort. The main results are: I) A 50-point category partitioning scale was identified to be most sensitive and reliable for scaling pressure intensity and discomfort; 2) Sensations of pressure intensity and discomfort linearly increase with the logarithm of the pressure stimulus level; 3) Thresholds for pressure intensity and discomfort in the seated ischium and thigh areas were derived; 4) The sensitivity of intensity and discomfort to the stimuli differs between the locations .The mid-thigh is more sensitive to surface pressure than the ischium. It is considered that this is due to differences in load adaptation, body tissue composition and deformation; 5) Local pressure discomfort dominates the overall discomfort, and ratings of the local discomfort are higher than those of overall discomfort. Part three discusses the findings from this research. Four integration models of the overall discomfort from local discomfort components were proposed. The Weighted Average model asserts that the overall discomfort is a linear combination of local discomfort components, and that the weight of each local discomfort is the proportion of this component out of the arithmetic sum of all local discomfort components. The mechanisms of discomfort were analysed. The fundamental research presented herein uniquely contributes to the knowledge on the human perception of seated pressure discomfort. Although this is not application based, the findings contribute to the methods of seating comfort evaluation as well as provide criteria by which seat designers may formulate design requirements.

In recent years, researchers have begun to focus on the communication of information using sound. This auditory display research community now has its own community and international conference (the International Conference on Auditory Display). Auditory Display embraces many interesting avenues of enquiry, one of which, program auralisation is the topic of this thesis. This thesis describes how the technique of program auralisation (the mapping of computer program data and events to sound) was applied within a musical framework and .context in the development of a musical program auralisation system called CAITLIN (the Computer Audio Interface to Locate Incorrect Nonsense). The motivation behind the construction of CAITLIN was to devise a system of auditory display that would assist novice Pascal programmers in debugging their code. Prior to this thesis, almost no experimentation had been carried out into this area. Earlier systems had been developed, but there was no empirical evidence against which to judge success or failure. Experimentation was carried out to assess the suitability of the technique as applied by CAITLIN. Novice programmers were engaged in several debugging exercises both with and without the assistance of the CAITLIN musical program auralisations. The results from the experiments have suggested circumstances in which such auditory feedback may indeed be useful. Further development and experimentation needs to be carried out to explore the potential of the technique. A set of organising principles for the use of music in program auralisation has been proposed on the basis of this research and a review of earlier work in the auditory display, music cognition, and music-theoretic fields.

This thesis describes the development and evaluation of a theoretical framework to account for the dynamic aspects of behaviour at the Human-Computer Interface (HCIF). The purpose behind this work is to allow for the consideration of dynamic Human-Computer Interaction (HCI) in the design of interactive computer systems, and to facilitate the generation of design tools for this purpose. The work describes an example of a design tool which demonstrates how designers of interactive computer systems may account for some aspects of the dynamics of behaviour, involved with the use of computers, in the design of new interactive systems. The thesis offers empirical and literary evidence to support the validity of the dynamic factors governing the interaction of humans with computers.

This thesis examines the use of music for communicating information on the Human-Computer Interface. The current use of auditory signals (including the limited use of music) is reviewed and the perceptual advantages and drawbacks inherent in the use of music are identified.

Que ce soit dans le domaine civil ou militaire, les progrès technologiques de ces dernières décennies ont permis l’émergence de nouveaux systèmes de communication facilitant grandement les échanges d’information. Ces nouvelles capacités de partage d’informations tactiques ont fait alors émerger des questionnements sur les moyens de restituer ces données dans le contexte du combattant débarqué. Le concept de « Réalité Augmentée » ou RA a notamment exploré, afin de fournir ces informations tactiques directement dans le champ de vision du soldat via l’emploi de « lunettes » de RA ou Head-Mounted Display (HMD).Rapidement, l’usage de ce type de dispositif souleva de nombreuses problématiques techniques mais aussi de l’ordre des Facteurs humains. En effet, ces nouvelles interfaces émergentes sont fondamentalement différentes des IHM classiques en deux dimensions sur écrans. Elles soulèvent donc des problématiques ergonomiques spécifiques qui doivent être étudiées afin de concevoir des systèmes de RA pertinents et adaptés à l’activité du fantassin débarqué du futur.Afin de pouvoir fournir des recommandations ergonomiques pour la conception, les travaux de cette thèse se sont orientés vers l’élaboration d’un cadre d’analyse de la RA, la taxonomie WOTSH&R. Ensuite, cette dernière a été appliquée pour l’évaluation ergonomique, au travers de différentes études exploratoires de système de RA pour le fantassin. Elle a notamment permis d’identifier et de traiter par la suite la problématique de la perception des distances. Enfin, la taxonomie a aussi été utilisée à des fins de conception et a permis le développement de deux preuves concepts d’IHM innovantes en réalité augmentée. / Whether in the civil or military field, technological progress in these last decades allowed the emergence of new communication systems improving greatly information exchanges. These new capabilities raise issues concerning the relevant display modalities in the context of the dismounted soldier. The concept of "Augmented Reality" or AR, has been explored to provide tactical information directly into the soldier's field of view through the use of of AR "glasses" or Head-Mounted Display (HMD). Soon, the use of this type of device raised many technical issues as well as Human Factors ones. Indeed, these emerging interfaces fundamentally differ from traditional two-dimensional screen-based HCI. It therefore raises specific ergonomic issues that need to be studied to design relevant AR systems adapted to the future infantry land warfare. In order to provide ergonomic design guidelines, the work of this thesis focused first on the development of a methodological framework tailored to AR. This taxonomy, named WOTSH&R, was then applied to the ergonomic evaluation, through various exploratory studies on military AR systems. It was successful in identifying and addressing the major problem of depth perception in particular. Finally, this taxonomy was also used for design purposes and allowed the development of two innovative augmented reality proofs of concept.

La gamification est le processus conduisant à l’emploi d’éléments de jeux adaptés au profil des utilisateurs dans des systèmes professionnels numériques afin d’accroître leur motivation, leur engagement avec un accent mis sur des interactions agréables voire de l’amusement. Ce concept récent questionne l’ergonomie, a fortiori dans un contexte professionnel. Il y a un besoin de définition, de mise en œuvre, d’évaluation et de réflexion sur ce qui engage l’utilisateur et sur son sens. L'expérience 1 analyse la perception de la gamification chez des concepteurs qui doivent identifier et catégoriser les éléments ludiques d’interfaces. Deux dimensions apparaissent : cosmétique et implicative. L'expérience 2 s’intéresse à la perception de la gamification chez des utilisateurs finaux avec un comparatif système gamifié / non gamifié. Les analyses révèlent que la gamification possède un impact primaire positif et un impact secondaire non désirable. Ensuite, un guide de conception est construit avec une description du processus de conception et une boîte à outils (principes généraux, arbres de décision, grille de conception). Il est validé lors de l’expérience 3 où des sujets doivent gamifier un système avec ou sans le guide. Les résultats indiquent qu’il favorise la fluidité, la flexibilité, l’originalité et l’élaboration. En définitive, ces travaux apportent des précisions conceptuelles et des clés de réflexion autour de l’idéologie de la gamification et des ressorts psychologiques employés pour engager, motiver mais aussi persuader, induire des comportements et contrôler. Pour finir, les suites à donner à ces travaux et l'avenir de la gamification sont abordés. / Gamification is the process of using game elements in professional digital systems, elements which are tailored to users’ profiles in order to increase their motivation and commitment with an emphasis on appealing, even amusing, interactions. This digital interface design modality questions ergonomics, especially when applied to professional contexts. Gamification needs to be defined, designed for and evaluated. Furthermore, the mechanism behind user commitment and the meaning of gamification needs to be carefully considered. The first experiment analyzes the perception of gamification by designers. They have to identify the ludic parts of gamification interfaces and then to categorize it. Two dimensions are identified: cosmetic and involvement. The second experiment analyzes the perception of gamification by end users through a comparison between gamified and non gamified versions of an interface. Analyses reveal that gamification has a primary impact, which affects positively the interaction, and an unwanted secondary impact. Then, a design guide is created which consists of a description of the design process and a toolbox (main principles, decision trees, design grid). It is validated through a third experiment: subjects, split into two groups (with / without the guide) are asked to gamify a system. The results show that the guide favors fluidity, flexibility, novelty and details. To conclude, this work provides conceptual details as well as a discussion about the ideological part of gamification and the psychological techniques, which are used to commit and motivate as well as to persuade, change behavior and control. Finally, next steps for research are suggested.

Inclusive Design is a concept that aims to design mainstream products, workplaces, services and facilities that can accommodate or `include' a maximum percentage of the user population disregarding their age and/or disabilities. The main idea behind Inclusive Design is to design products or workplaces that can be used by all including older, disabled and able-bodied people rather than having two streams of products. There are many social and economic benefits in achieving inclusivity in design such as improving the life of the elderly and disabled people and reaping the profits from the market that extend because of the increased number of consumers. Origins of Inclusive Design go back several decades and are due mainly to the demographic, legislative, and social as well as economic changes that occurred during this period. This research was conducted to study methods of implementation of Inclusive Design. The research has shown that although there are many advantages of designing for the whole population, designers are reluctant to do this mainly because of the enormity of the task which can take up a huge amount of time and man-power. One solution to this can be found in design tools, which provide the designers with a means to achieve inclusivity relatively quickly and with less effort. Therefore this research has developed a new methodology and a computer tool to assist designers to implement Inclusive Design with ease. The methodology discussed in this thesis incorporates the physical characteristics of the users of products and workplaces in the design process in order to search for better configurations for designs. It is shown here that by considering the physical aspects of the individual users such as their anthropometry, joint constraints, capabilities etc in a design optimisation process, the percentage user accommodation of a product can be maximised. In order to achieve this, ergonomics analysis methods and mathematical methods were used to interpret user characteristics in terms of design variables and then constraint modelling was used to model the whole design problem and search for better solutions within the constraints of the design. To implement this method a software tool called SHIELDS was created. This tool utilises the capabilities of four other pieces of software to accomplish the design synthesis. These are HADRIAN and SAMMIE for ergonomics evaluation and MATHEMATICA for mathematical functions fitting and SWORDS constraint modeller to find best solutions. Two case studies were performed to test the functionality of the software and the validity of the methodology developed.

Orientador: André Luiz Félix Rodacki / Co-orientadora: Maria Lúcia Leite Ribeiro Okimoto / Dissertaçao (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduaçao em Engenharia Mecânica. Defesa: Curitiba, 2004 / Inclui bibliografia / Área de concentraçao: Gestao de produçao e ergonomia / Resumo: O objetivo desta pesquisa foi determinar alterações no padrão cinemático postural em escolares durante o transporte de mochila dorsal de alça bilateral de ombros. Foram recrutados 10 sujeitos (13,9 ±0,6 anos, 44,92 ±3,28 kg; 1,53 ±0,05 m) que deambularam em velocidade constante em esteira ergométrica sem carga e com carga de 10% e 20% do peso corporal. Um conjunto de marcas cutâneas forneceu dados que permitiram a reconstrução dos movimentos da coluna vertebral em três dimensões e serviram para calcular um número de variáveis. Os dados obtidos na condição de marcha sem carga serviram como referência para que as outras duas condições de transporte (10% e 20%) fossem comparadas. Os resultados mostraram inclinação anterior do dorso durante todo o ciclo da marcha, independente do peso da carga transportada. Cargas de 20% do peso corporal causaram aumentos mais pronunciados sobre a inclinação anterior do tronco em comparação ao transporte de 10% do peso corporal. Tais mudanças foram atribuídas a uma estratégia para compensar a mudança do centro de gravidade do sistema causado pela mochila. O ângulo entre os ombros e os quadris evidenciou uma maior rotação da coluna vertebral no plano horizontal durante o transporte de carga de 20% do peso corporal. Esses achados podem estar associados às alterações dos parâmetros dinâmicos da marcha para manter a velocidade de deslocamento constante e para facilitar a fase de balanço durante o transporte de cargas mais pesadas, aumentando a eficiência mecânica da marcha. Os resultados indicam a existência de ajustes adicionais na condição de transporte de 20% em relação à condição de transporte de cargas de 10% do peso corporal. Desta forma, o transporte de carga equivalente a 20% do peso corporal produz maior alteração sobre o padrão cinemático da coluna vertebral em comparação a cargas de 10% do peso corporal. Portanto, o transporte de carga de 20% do peso corporal pode induzir a esforços musculares excessivos, fadiga e aumentar a suscetibilidade de lesão do aparelho locomotor. Recomenda-se que o limite de carga a ser transportada por escolares por meio de mochila dorsal seja inferior a 20% do peso corporal. Sugere-se que o peso de mochila escolar não deve exceder a 10% do peso corporal, uma vez que não foram observadas alterações acentuadas sobre a coluna vertebral, os quais se assemelham aos padrões da marcha sem carga. Palavras-chave: Carga; Mochila Escolar; Marcha; Postura; Cinemática. / Abstract: The aim of this study was to determine alterations in the postural kinematic pattern in scholars during the transport of a dorsal backpack. Ten subjects (13,9 ±0,6 years, 44,92 ±3,28 kg; 1,53 ±0,05 m) were recruited and walked in a treadmill with constant speed without load and carrying loads (10% and 20% of their body weight). A set of skin markers provided data that allowed a three-dimensional the spinal movements reconstruction, from where a number of variables were calculated. The data obtained in the gait condition without load were used as a reference to compare the other two experimental conditions (10% and 20% body weight). The results showed anterior inclination of the torso in ali phases of the gait, independent of the weight of the backpack. Loads of 20% of body weight caused the most pronounced increases on anterior leaning of the trunk in comparison to the 10% body weight condition. Such alterations were attributed to compensatory strategy in response to changes in the system center of mass, caused by the backpack. The angle between shoulders and hips evidenced a larger rotation of the spine in the horizontal plane during the transport of loads of 20% body weight. This alteration may be related to changes in gait dynamic parameters in order to keep the displacement speed constant and to facilitate the swing phase during the transport of heavy loads that increase gait mechanical efficiency. The data indicate the existence of additional adjusts in the condition of 20% body weight in relation to the condition of 10% body weight. Therefore, the transport of loads of 20% body weight may result in greater changes over the gait cinematic pattern of the vertebral column in comparison to that observed during the transport of loads of 10% body weight. Hence, the use of loads correspondent to 20% body weight may induce excessive muscle strain, fatigue and increase susceptibility to injury of the locomotor's apparatus. It is recommended that the load limit to be transported by scholars to be inferior to 20% of their body weight. It is suggested the weight of the transported load to not exceed 10% body weight, since no marked changes over the spine were observed, which were similar to that observed inn the unloaded condition. Key-words: Load; School Backpack; Gait; Posture; Kinematics.

The main aim of the research presented in this thesis is to inform the design of interactive computer systems for supporting creative knowledge work. Research into creativity and knowledge work has been explored and used to develop a criteria modelling approach. The particular contribution of the author's work is the drawing together of that research and applying the findings to interaction design. The publications were selected on the basis of how well they represent the main outcomes of the work. The journey from prescribing system requirements and design goals to framing the system design process in terms of evaluation criteria may be traced through the papers presented. Interest in creativity and the role of computer technology in creative tasks has recently increased. A number of national initiatives have been set in motion in the LJK, beginning in December 1996 with the Initiative for National Action on Creative Technologies, the Creative Media Initiative: Technology Foresight, Department of Trade and Industry, National Endowment for Science and Technology in the Arts (NESTA) and the People and Computers Programme, of the Engineering & Physical Science Research Council (EPSRC). Thus, the author's involvement in creativity research and computer support is proving to be timely. Amongst her recent initiatives is Creativity and Cognition, an international symposium which brings together creative people in the arts with technologists and scientists. The thesis is divided into three parts : themes and outcomes, methodology and case studies. A criteria-based modelling approach is presented which has evolved from earlier models that represent key elements of creativity and knowledge work. A model of creative knowledge work is proposed and categories of criteria identified. Underpinning the main outcomes are the case studies which were carried out in industry/academic collaborative projects. The findings were considered in relation to other studies. The thesis presents an approach to computer systems design and development that directly links the requirements definition to the application of evaluation criteria. These criteria are based upon the characteristics of the cognitive style and working practices of creative knowledge workers.

The overall objective of the research has been to address the question of how best to understand user behaviour at the interface. The use of cognitive grammars to analyse tasks and predict behaviour was rejected for seven theoretical and practical reasons. Following this, cognitive style measures were rejected as a result the first study, where the visualizer-verbalizer and conceptual tempoc ognitive style measures were not found to be accurate predictors of behaviour at a task. The results of this experiment indicated that interaction between a system and its user has certain dynamic qualities that make prediction of a fixed set of activities in a set order difficult. Furthermore, it seemed likely that behaviour is determined by a potentially complex interaction of variables rather than any single over-riding factor, such as a user's cognitive style. Consequently, attention was-focused upon the errors that occur during humancomputerinteraction. An approach where errors are classified was -adopted, and a classification scheme was developed (ECM: an Evaluative Classification of Mismatch)as a vehicle for further research. An initial pilot study showed that user-system errors could be classified using the scheme. This suggested that the concepts it employed did have some validity in'both cognitive and computing domains. The second study of ECM involved a design team at Hewlett Packard's Office Products division in Wokingham. This study demonstrated that the classification scheme was - usable by a design and development team that consisted of software engineers, human factors engineers, and technical authors. The third and final study of ECM demonstrated that it could be, used to improve a design. A system, that had been changed using ECM, was shown to be significantly better, in terms of time, errors and user attitude ratings, than either its original or an iteration where ECM had not been employed. This research has provided strong indications that evaluative classifications can be of use within the design and development process. Furthermore, this work emphasizes the importance of providing structures for thinking about the user's problems that are divorced from the structure and terminology of design.