Power Explorer – a casual game style for encouraging long term behavior change among teenagers

When it comes to motivating teenagers towards energy awareness, new approaches need to be considered. One such is the use of pervasive games connected to the players own energy consumption. Earlier work has confirmed this to be a highly effective approach. The question however remains if post game effects on behavior can be achieved. In this paper we try to answer this by trying out a slightly different design compared to previous work. The hypothesis is that a more casual game play and a richer learning interaction enabled by building the game on a real time sensor system could stimulate more lasting effects. Electric consumption data after the 7 days evaluation on a test group of 15 players shows tentative indications for a persistent post game effect compared to the control group of 20 households. Findings also show a statistically significant positive change in the players’ attitude towards saving energy compared to the same group. Findings, at the same time, also indicate a negative effect on the player’s attitude toward environmental questions in general

Persuasive design of a mobile energy conservation game with direct feedback and social cues

Pervasive gaming has the potential of transforming the home into a persuasive environment in which the user can learn about appliances and their electricity consumption. Power Explorer is a mobile game with a special sensing approach that provides real-time electricity measurements and feedback when the user switches on and off devices in the home. The game was developed based on persuasive principles to provide an engaging means to learn about energy with positive and negative feedback and social feedback from peers on real energy actions in the home. We present the design and rationale of this game and discuss how pervasive games can be viewed from a persuasive and learning point of view

Consumer Perceptions of Additions to Geographic and Social Space

This position paper introduces a relationship between ambient media and pervasive games, and opens both fields up to an analysis with the HeuristicSystematic model of persuasion based on the relationship between the two fields. The paper concludes with an invitation to discuss the relationship between the ambient media user experience and the kind of brand equity, as measured by the two-tiered persuasion model, that ambient media can build

The Undercut Criterion of Pinion Shaper Cutters: And an Improvement by Modifying the Basic Rack Profile

The fillet of the gear tooth is highly stressed in operation; so for heavily loaded gears, the fillet geometry must be controlled. The manufacturer's task is to, within acceptable tolerances, produce the gear to the designer's specifications regardless of the manufacturing method. Most often gear cutting tools are used that work under generating conditions. The tool will form the gear tooth; so to produce the specified gear geometry and, especially, the fillet geometry, this tool must be conjugated to the same basic rack as the gear to cut. However, this gives a risk that the tooth tip of the tool will be undercut, and if this occurs the tool will not cut the intended gear fillet. In this report, novel analytical equations are derived, which predict the limit when the tool tip will be undercut. It is shown that if the gear tooth should be conjugated to the standard basic rack with a circular fillet, which is the normal case, very large tool-tooth numbers are needed for pinion shaper cutters and gear skiving cutters to avoid this type of undercut. However, the minimum tooth number to achieve a smooth continuous tool-tooth profile is reduced by modifications to the fillet of the basic rack profile

On the Machining of Involute Helical Gears - Prediction models on tool geometry, cut gear tooth surface topography, chip geometry, and tool cutting forces

The modern requirements on power transmissions focus on energy efficiency, low noise and dynamic vibrations, and power density. In order to meet these requirements, the gear wheels must be manufactured to very high precision. Additionally, it should be economical to manufacture these gears within the tight requested tolerances. Gears manufactured within automotive, truck, and construction equipment are usually cut using milling tools. The profile accuracy and the surface roughness achieved after manufacturing, which determines the gear quality, are connected to the process parameters and possible manufacturing related errors. Prediction models to accurately determine gear quality, where tool and process related errors are taken into account, are needed in order to improve the manufacturing process. Tool life has also a strong economic impact in machining operations. Tool life prediction is an important part in optimization of the machining processes, where tool life is strongly connected the cutting forces and the geometry of the cut chips. In this work mathematical models are established in parametric form, based on analytical differential description. These models are developed in order to increase knowledge and understanding of the complex machining processes involved in gear manufacturing. Focus is on the cut gear tooth surface quality, and on milling related topics, such as cut chip geometry, tool cutting forces, and tool wear prediction. The mathematical models are used in a number of experimental studies presented in this thesis. The experimental studies were performed in industrial conditions, where tool and process related errors that are common in industrial applications have been considered. The correlation is very good, which shows the industrial applicability of the presented models

Alignment Deviations on a Lead Crowned Helical Gear Manufactured by a Hob

Gear hobbing is well established and one of the most cost effective manufacturing methods of involute gears. In the hobbing of lead crown corrected helical gears, a well know drawback is the non-uniform systematic tooth alignment deviation that arises. This is sometimes denoted as flank twist. The inevitable tooth alignment deviation, together with other source deviations, must not exceed the specified tolerances if the gear is to be finished hobbed. To avoid trial and error when selecting manufacturing method, it would be of great industrial interest to be able to predetermine the least expected alignment deviation when the gear is to be finished hobbed. The main purpose of this study is to determine the magnitude of the systematic alignment deviations which arises for hobbed gears with lead crown correction. A simulation tool is developed where the hobbing process can be analysed, without additional errors resulting from real conditions. The results from this simulation tool show very good correlation with an experimental gear ground by a hob in industrial conditions. By elimination of feed marks on the gear tooth surface, a novel method to predetermine the least expected alignment deviation was found by an analytical analysis. The results from these studies can be used as a guideline when selecting manufacturing method for involute gears

Prediction of alignment deviations on a lead crowned helical gear manufactured by a hob

A drawback when hobbing lead crowned helical gears is that the gear tooth will be manufactured with alignment errors, often denoted flank twist. Together with other source deviations, these errors must not exceed the predetermined tolerances if the gear is to be finished hobbed. A simulation model is developed where the hobbing process can be analysed without additional errors resulting from real conditions. The result from this simulation model show very good correlation with an experimental gear ground by a hob. An analytical analysis of the manufacturing process results in a novel method to predetermine the minimum alignment deviations on a hobbed gear tooth. When selecting manufacturing methods, the results from this study can be used to determine if a hob can produce the helical gear within given tolerances

Optimum dog-leg angle for mass and bearing force optimization of multistage gear reduction

This paper describes a method to minimize bearing forces as well as bearing and housing mass for a multistage gear reduction. This is done by finding the optimum dog-leg angles for the stages while leaving other aspects of the design unaltered. The optimization is demonstrated first for spur gears, and then for helical gears typically used in electric vehicles. A numerical example shows how bearing forces and mass of bearings and housing are reduced considerably by choosing the optimum dog-leg angle