# Application of Online Transportation Mode Recognition in Games
## 4 Methodology
### Gravity Measurement Miscalibration  
After the initial positive tests on classifier accuracy, a real-life test is carried out with the same classifier integrated into the game. Due to the number of errors that emerge, we hypothesise that the device orientation could have impacted the transport recognition. Brief tests reveal that the total gravity sensed varies with each device and orientation, which would in turn affect all machine-learning classifier results including the accelerometer. Figure 5: Historical set with serial sleep sessions. Figure 6: Effect of sensing and sleep session intervals ratio on the number of errors. To justify the need of acceleration sample data normalisation on an Android device, orientation gravity measurements are collected and presented in Table 2. The columns represent different volunteers' respective devices, with standard deviations presented both on a per-device and per-orientation basis. Note the increased deviations for the face right and face left orientations, which are common for devices placed in pants' pockets while sitting. In order to ensure that the whole procedure and data are thoroughly device and orientation ambiguous, as well as remove the effect of sensor-axis miscalibration, normalisation of acceleration values is applied to the minimum, maximum, and averages of the acceleration sensor magnitude values. This is done by subtracting the mean from each value and dividing the difference with the mean. * Evergreen Persuasive Game: An Evergreen game server is a Java-based back-end to support the co-ordination of online multi-player game mode. Details about the game are discussed as follows: game genre; game goals; game fantasy; game curiosity; game design details. Game Genre: A turn-based strategy and role-playing game hybrid is chosen. There are several reasons for this. Firstly, it enables an iterative approach to persuade players for each turn or day that they are playing the game. Secondly, players of role-playing games tend to play them for a long time, as long as they are well-designed. In the game, each turn would correspond to one real-life day. Actions in real life (transport mode taken) would affect, to some extent, results in the game and, thus, give an incentive for players to subsequently choose greener modes of transportation. Using a turn-based approach also makes it available to a larger audience, as less time is required to play it (a few minutes per turn or day), whereas a real-time game may distract and interfere with daily life. Pokemon Go is a great comparison as it is also in the same kind of genre, has garnered huge popularity, caused a distinct change in behavioural patterns of players, though it has disadvantages and hazards inherent in the game design [43,44]. Game Goals: The primary goal of this research work is to design a persuasive game to: (i) reduce carbon emissions via opting for greener forms of transportation; (ii) promote awareness of environmental footprint; (iii) defeat other players by being the longest survivor. To maintain the game captivation element, the first and second implicit sub-goals are built into the game. They appear as tools and parameters in the game that players can use to achieve the third sub-goal. Within the resulting game, these goals are integrated into the generation of random events that are spawned subjecting to the type of transport players use, as well as one of the main game statistics called 'Emissions'. The third sub-goal is a typical game goal that resonates well with general and contemporary game designs because it is likely to evoke emotions and is more likely to entice game players. Within the game, players may also set their own goals--such as helping others, building the largest shelter, etc. Due to the complexity of the resulting game (and role-playing games in general), players tend to set up different own goals based on what they most enjoy in games.