Evaluating functional clothing in climatic chamber tests versus field tests: a comparison of quantitative and qualitative methods in product development

For the evaluation of clothing by human beings, two different approaches can be identified- laboratory tests (i.e. climatic chamber tests) or field trials/wear trials. It has been suggested that the performance of clothing can be adequately predicted on the basis of the data obtained from climatic chamber tests and that field trials may be expendable altogether. From a product development perspective, this paper discusses the information provided by standard data collection methods and tools for the assessment of thermal comfort used in laboratory settings and compares this information with that acquired in field trials. When assessing the information provided in the laboratory test against those questions posed in a development process, the results highlight the insufficiency of objectively measurable criteria. Therefore, objective measurements alone cannot verify the adequacy of stated requirements for thermal comfort. The use of appropriate and sensitive tools for collecting subjective votes should also be noted, since small differences in thermal sensation affected the individual's preference for clothing. Exposed differences between subjects, in terms of thermophysiological as well as subjective responses, illustrate the importance of studying individual values and deviations as opposed to strict mean values for large populations in order to satisfy a potential user group. It is argued that complementary interviews form a basis for further understanding of ratings and preferences and that they should also be included in the climatic chamber evaluation 'tool box'. User satisfaction is based on a simultaneous assessment of partly opposing properties into a satisfying use value. Although laboratory test procedures can be developed and improved in relation to design issues, field evaluations must be regarded as an integrated part of an iterative development process. Only the actual use situation can provide the total spectrum of conditions on which basis requirements and/or properties can be prioritized or downgraded. This information forms the prerequisite for successful product development.     

Ergonomics, education and children: a personal view

Educational ergonomics - the teaching of ergonomics and the design of environments where ergonomics teaching and learning might occur - has received little attention from ergonomists. This paper first describes the roots of the author's interest and research in educational ergonomics; second it provides a personal view of the opportunities and challenges posed by the two streams of educational ergonomics; and lastly it considers the implications of teaching ergonomics to children in terms of their personal development, the design of schools and the impact such initiatives might have on wider societal problems.     

Ergonomics evaluation and redesign of a hospital meal cart

The ergonomic, design and other problems of a conventional hospital meal cart were evaluated with a view to redesign a hospital meal cart by incorporating ergonomic principles and data. The operators encountered difficulty in setting the cart in motion, seeing over the cart, turning the cart and stopping the cart while in motion. The operators expressed postural discomfort in the shoulder, neck, back, lower back, knee and leg, and ankle and foot. The cart with meal trays and food was found to exceed the acceptable initial turning push force requirement of 5th percentile females. Recommendations were made for proper placement of cart handles and handle diameter, provision of large-diameter cart wheel made of hard rubber tire, reduction of cart height, use of plastic material for cart construction, provision of emergency brake, provision of individually (electrically) heated plates for soup and main meal, provision of thick air-tight transparent plastic doors, and reduction of the meal tray size. Several recommendations were adopted by the manufacturer in the new model.     

Feature-based ontological framework for semantic interoperability in product development

An essential requirement in integrating tasks in product development is to have a seamless exchange of product information through the entire product lifecycle. A key challenge in the integration is the exchange of shape semantics in terms of understandable labels and representations. A unified taxonomy is proposed to represent, classify, and extract shape features. This taxonomy is built using the Domain-Independent Form Feature (DIFF) model as the representation of features. All the shape features in a product model are classified under three main classes, namely, volumetric features, deformation features and free-form surface features. Shape feature ontology is developed using the unified taxonomy, which brings the shape features under a single reasoning framework. One-to-many reasoning framework is presented for mapping semantically equivalent information (label and representation) of the feature to be exchanged to target applications, and the reconstruction of the shape model automatically in that target application. An algorithm has been developed to extract the semantics of shape features and construct the model in the target application. The algorithm developed has been tested for shape models taken from literature and test cases are selected based on variations of topology and geometry. Results of exchanging product information are presented and discussed. Finally, the limitations of the proposed method for exchanging product information are explained.     

A methodology to redesign heterogeneous product portfolios as homogeneous product families

This paper presents a methodology to redesign heterogeneous product portfolios as homogeneous product families. A heterogeneous portfolio is one that has no common components, or shares a minimum number of components. The methodology proposed to homogenize the portfolio begins by analyzing the current product offerings to determine customer needs and functions. Then, a granulation process is initiated to remove redundancies, and identify physical function carriers to deliver the required functions. Next, function carriers are grouped on the basis of their functional commonalities into groups for parallel development. The applicability and the use of the methodology are illustrated through the redesign of an existing heterogeneous ‘office furniture’ product portfolio.     

Data management of green product development with generic modularized product architecture

Many manufacturers are facing a complex situation in the mixed production environment, in which green and non-green products are fabricated simultaneously. They are losing competitiveness as a downstream supplier due to lacking of a cost-effective approach to managing product variations compliant with different green directives. This paper presents a methodology based on generic modularized product architecture that facilitates data management of green product development. The four-level architecture allows one unified representation for multiple product models. An option control mechanism enables a quick generation of their BOMs (bills of material). A procedure consisting of seven steps is proposed to accomplish this. PDM functions are implemented to demonstrate the effectiveness of the methodology using a real LCD TV family as an example. This work complements the past studies on green product development, which mainly tackled the problem from design, process, and supply chain improvement. In contrast, from a management perspective, the proposed methodology provides a simple but useful tool for small-to-medium-sized enterprises (SMEs) to perform green product development in an economical manner.     

Elements in a new sustainable industrial culture Environmental assessment in product development

In the last few years the environmental focus in the manufacturing industry has shifted from the manufacturing processes to the products themselves, as these are accountable for the environmental impacts in all life cycle phases. The paper describes for three industrial cases how a newly developed LCA methodology can assist the product developer in development of more environmentally friendly products. Finally, common experience gained will be discussed.     

User-oriented product development applied to functional clothing design

A method for user-oriented product development is presented. After a theoretical introduction the method is applied to the development of functional clothing. The characteristic of the method is its starting-point with the user in the use-situation. Important product demands are derived from use-analyses. Three case-studies are described where this method has been applied. They concern working clothes, clothes for the elderly and military clothing. The quality of this methos as an instrument for product development in the clothing area is evaluated by comparing, on the one hand, this method with those usually used in the clothing industry, and on the other hand the new products with those formerly used. The method for user-oriented product development has proved to be complementary to conventional methods. It should be applied to products whose functional properties are of great importance. The method can be generalised to all users and to products with close connection to human beings.     

Optimal platform investment for product family design

Existing models for developing modular product families based on a common platform are either too engineering oriented or too marketing centric. In this paper, we propose an intermediate modeling ground that bridges this gap by simultaneously considering essential concepts from engineering and marketing to construct an alternative model for platform-based product families. In this model, each variant (in the platform-based product family) contributes a percentage to overall market coverage inside a target market segment. The extent to which a specific variant contributes to market coverage is linked to its degree of distinctiveness. On the other hand the cost of development of all variants (that constitute the product family) is also dependent on the degree of commonality between these variants. The objective of the model is to maximize market coverage subject to an available development budget. Based on a conceptual design of the product family, the proposed model suggests the optimal initial investment in the platform, the commonality level between variants, and the number of variants to be produced in order to maximize market coverage using both analytical and simulation techniques. An application example using an ice scraper product family is included to demonstrate the proposed model.     

Ergonomics evaluation of a manually operated cassava chipping machine

A manually operated machine for chipping cassava was evaluated. Six farmers took part in the study, with physiological, postural, and subjective measurements being taken. Using the machine resulted in drudgery and postural discomfort. Following an iterative design process and using appropriate anthropometric measurements, an improved, adjustable prototype was developed. This was tested with the six farmers and six novice users. It was found to reduce discomfort and physiological strain, allowed a faster work-rate (with novice users) and was preferred by all users. The study demonstrated how ergonomics can play an important role in reducing drudgery and improving user satisfaction in technology development and transfer in developing countries.     

Kansei engineering as a powerful consumer-oriented technology for product development

Kansei engineering was founded 30 years ago, as an ergonomics and consumer-oriented technology for producing a new product. When a consumer wants to buy something, he/she will have a kind of feeling and image (kansei in Japanese) in his/her mind. If the consumer's feeling could be implemented in the new product, he/she would be more satisfied with the product. Kansei engineering aims at translation of kansei into the product design field including product mechanical function. This is why it is called the consumer-oriented aspect. There are many products in Japan which have applied kansei engineering. Recently, it has also been applied to construction products as well as to community design.     

Applying principles of mass customization to improve the empirical product development process

Applying methods of mass customization to the empirical process can improve product development process efficiency and reduce time and cost. Empirical methods are used to develop predictions of product behavior in conjunction with analytical methods or instead of analytical methods. These empirical methods represent a complete sub-product development process within the overall product development process. Application of process decomposition and planning used in mass customization can improve the efficiency, lower the time and cost of these empirical processes. This paper presents a method for applying principles of mass customization to the empirical sub-processes within a product development process. Two case studies are also presented to demonstrate the method.     

Multiple-view feature modelling for integral product development

To allow a designer to focus on the information that is relevant for a particular product development phase, is an important aspect of integral product development. Unlike current modelling systems, multiple-view feature modelling can adequately support this, by providing an own view on a product for each phase. Each view contains a feature model of the product specific for the corresponding phase. An approach to multiple-view feature modelling is presented that supports conceptual design, assembly design, part detail design and part manufacturing planning. It does not only provide views with form features to model single parts, as previous approaches to multiple-view feature modelling did, but also a view with conceptual features, to model the product configuration with functional components and interfaces between these components, and a view with assembly features, to model the connections between components. The general concept of this multiple-view feature modelling approach, the functionality of the four views, and the way the views are kept consistent, are described.     

Power-based supplier selection in product development projects

As stronger supplier might exert their power to influence a product development project for their own benefit, business negotiations will be more efficient if the customer has a clear understanding of its power with regards to each of its potential suppliers. This article takes the customer perspective in dealing with supplier selection and proposes a method to estimate the power of a customer versus potential suppliers. Based on an evaluation of their power, potential suppliers are then ranked. This selection procedure is illustrated with an example and evaluated against a case study taken from academic literature.     

Ergonomics in Systems Design

The relationship between ergonomics and systems design is defined and its importance is stressed. The origins of systems ergonomics are described and it is suggested that the technology of ergonomics now depends primarily on the science of psychology with some importance still attached to anatomy but with physiology now of marginal relevance. The differences in approach and objectives between systems ergonomics and classical ergonomics are summarized and, although it is admitted that our expertise in these fields is not adequate for our practical responsibilities, it is concluded that the progress of science and technology in both engineering and human factors are now inter- and cross-dependent.     

Ontology-based interoperation model of collaborative product development

The reuse of existing systems is an important objective of High Level Architecture (HLA) based collaborative product development systems. However, in order to reuse an existing system, its interoperation interface has to be modified so as to comply with the objective and interaction representations defined in a corresponding Federation Object Model (FOM). Such modifications imply added time and effort, which diminishes the efficiency of system reuse in collaborative product development. This paper presents a heavy-weighted ontology-based construction method for interoperation models to support the reuse of subsystems in various collaborative contexts. In this method ontologies are used to specify the semantics of object classes and interaction classes in subsystems in a formal and computer readable fashion. In doing so, a Formal Concept Analysis (FCA) like construction method is introduced to establish the original interoperation ontology from scratch. An automatic transforming method from Simulation Object Model (SOM) into interoperation ontology is also described to make existing HLA based systems easy to adopt this approach. Then a consistency verification method is introduced to guarantee the consistency of the interoperation ontologies. A case study is used to demonstrate the feasibility of the proposed method. As a human-friendly modeling method, compared with existing interoperation modeling methods the proposed method is more flexible, efficient and reliable.     

Establishing a dynamic ergonomic evaluation index system for complex product designs based on the theory of product life cycle

Ergonomic design and evaluation for complex product (tractor as an example) in different lifecycle stages should be different and specific according to changing business strategies. Being key factors for multi-attribute evaluation, how to define indicators and assign weights to them for tractor's different lifecycle stages are discussed in this paper. Focus group has been used for brainstorming initial indicators as many as possible. Then, indicators and their relationship-structures for three lifecycle stages were assessed and optimized by two rounds of Delphi surveys involving 15 experts. After that, a synthetic indicator weight assignment method suitable for value evaluation and ranking evaluation was proposed. Indicators' weights for value evaluation was composed by experts' value judgment weight and experts' credibility weight, the former was assigned by Group Analytic Hierarchy Process method and the latter was assigned by calculating distances between individual weight and the average weight. To differentiate alternatives' ergonomic performances clearly, weight set of value evaluation has been modified by indicator's information entropy weight. The results show that there are some significant differences in three indicator systems (for three lifecycle stages) and weight sets developed by the proposed method, and this will have significant impacts on ergonomic evaluation results, which can provide useful feedback for tractor's design during its early design stage. The proposed method can be applied to ergonomic evaluation study of other complex products in their lifecycle.     

虚拟企业环境下的复杂产品并行开发框架模型研究

为了解决虚拟企业中复杂产品开发的并行调度问题，提出了虚拟企业环境下的复杂产品并行开发框架模型。该模型在采用设计结构矩阵和扩展工作转秽矩阵分析产品并行开发过程中存在的循环迭代基础上，运用遗传算法对开发任务的调度进行优化。仿真结果表明，该框架模型在处理虚拟企业的复杂产品并行开发方面的瓶颈问题有着显著的优势。