Open systems interconnection — the teletex-based session protocol: Part 2

The development of an international standard for the teletex-based session protocol has involved combining the best points of two draft proposals, ECMA 75 and S.62. Recently, the ISO has completed a specification comprising three subsets: the ISO/ECMA subset, the ISO/CCITT subset and the null functionality subset. The paper discusses the development of the standard, lays out the specification and describes the operation of each of the protocol phases. Three appendices describe the conformance problem and the BAS subset, protocol machines and the interworking problem.     

Drying of in situ cast concrete ground slabs and covering criteria

The main objective of this paper was to examine the overall moisture behaviour of an in situ cast concrete ground slab during the initial drying period of the fresh concrete from casting to flooring. This article describes and evaluates various methods to measure moisture levels in concrete slabs in order to decide if flooring can be attached. The most accurate method is verified against measurements and compared with calculations. Many of the methods only consider the surface moisture content of the slab and do not consider the moisture condition deep in the slab. According to performed laboratory tests and FE modelling, moisture content of the slab surface is not a reliable indicator of the overall moisture conditions of the slab. Residual moisture deep in the slab has a major effect on the moisture distribution at the slab cross-section after flooring. The only reliable method to determine the moisture conditions in a new concrete ground slab before flooring is to measure the moisture content at the equivalent depth of the slab. It reliably predicts the ultimate moisture content at slab/flooring interface after flooring. A ground slab is drying in two directions: towards the indoor air by evaporation from the slab surface, and towards the cooler subsoil layers by diffusion. The significance of drying downwards increases after the flooring assembly.     

Occupants’ acceptability of zero energy housing in Finland

Based on an extensive Finnish data covering 1350 interviews the authors surveyed the end users’ perceptions concerning improved energy efficiency, renewable energy integration and zero energy housing. The data has wide social coverage and it matches well with both age and gender distribution in Finland. The survey indicates that solar photovoltaic panels and heat pumps are among most familiar renewable energy technologies to the interviewed occupants while the panels also enjoy the most positive image among the interviewees. However, the interviewees’ willingness to pay extra for energy efficient improvements was more munificent than that for the renewable energy installations. Zero energy buildings were only known to roughly half of the interviewees while 48.9% of the respondents did not even know whether there is an energy performance certificate for their house or not.     

Three-dimensional modeling of removal torque and fracture progression around implants

In the present study, a model for simulations of removal torque experiments was developed using finite element method. The interfacial retention and fracturing of the surrounding material caused by the surface features during torque was analyzed. It was hypothesized that the progression of removal torque and the phases identified in the torque response plot represents sequential fractures at the interface. The 3-dimensional finite element model fairly accurately predicts the torque required to break the fixation of acid-etched implants, and also provides insight to how sequential fractures progress downwards along the implant side.     

Customer preferences in mobile game pricing: a service design based case study

This article examines the service design of freemium game pricing. Freemium games are a type of game that is partially free to play, but its players are able to access various options by playing real money. The article increases knowledge of the usability of service design processes in the pricing of mobile games, as well as the understanding of central aspects of freemium pricing models from the perspective of user experience and customer value. Existing research shows that one major reason for failing freemium pricing models is the orientation for technology development, alongside poor content and too aggressive monetization, rather than customer experience. The article presents a process in which an alternative pricing model was developed for freemium games, through the use of service design workshops.     

What if it Switched on the Sun? Exploring Creativity in a Brainstorming Session with Children Through a Vygotskyan Perspective

We contribute in this study a first step in theory-based understanding on how creativity in collaborative design sessions relates to the elements that are present in a creative act. These elements include group composition, objects present, practices used, and previous knowledge of the participants. The context of this study was our search for lightweight methods for technology design with children, which can be used in a school context with large groups, will require as little amount of training as possible, and can be set up quickly. We formed a mixed group, consisting of young children, an older child and an adult, with the aim of involving children in creative collaborative brainstorming during the very early phases of design, so as to come up with fruitful ideas for technology development. We report our process and examine the implications of our results in relation to different elements that trigger and affect creativity in the collaborative design process. Use of Vygotsky’s cycle of creativity as our theoretical lens together with timeline analysis method presented in the paper were essential for seeing beneath the surface of what happened in this complex, collaborative creative process. Our results can be used for further methodological development of creative collaborative sessions, both with children and adults.