Distal pointing is the interaction style defined by directly pointing at targets from a distance. It follows a laser pointer metaphor and the position of the cursor is determined by the intersection of a vector extending the pointing device with the display surface. Distal pointing as a basic interaction style poses several challenges for the user, mainly because of the lack of precision humans have when using it. The focus of this thesis is to understand and improve distal pointing, making it a viable interaction metaphor to be used in a wide variety of applications. We achieve this by proposing and validating a predictive model of distal pointing that is inspired by Fitts' law, but which contains some unique features. The difficulty of a distal pointing task is best described by the angular size of the target and the angular distance that the cursor needs to go across to reach the target from the input device perspective. The practical impact of this is that the user's relative position to the target should be taken into account. Based on the model we derived, we proposed a set of design guidelines for high-precision distal pointing techniques. The main guideline from the model is that increasing the target size is much more important than reducing the distance to the target. In order to improve distal pointing, we followed the model guidelines and designed interaction techniques that aim at improving the precision of distal pointing tasks. Absolute and Relative Mapping (ARM) distal pointing increases precision by offering the user a toggle which changes the control/display (CD) ratio such that a large movement of the input device is mapped to a small movement of the cursor. Dynamic Control Display Ratio (DyCoDiR) automatically increases distal pointing precision, as the user needs it. DyCoDiR takes into account the user distance to the interaction area and the speed at which the user moves the input device to dynamically calculate an increased CD ratio, making the action more precise the steadier the user tries to be. We performed an evaluation of ARM and DyCoDiR comparing them to basic distal pointing in a realistic context. In this experiment, we also provided variations of the techniques which increased the visual perception of targets through zooming in the area around the cursor when precision was needed. Results from the study show that ARM and DyCoDiR are significantly faster and more accurate than basic distal pointing with tasks that require very high precision. We analyzed user navigation strategies and found that the high precision techniques afford users to remain stationary while performing interactions. However, we also found that individual differences have a strong impact on the decision to walk or not, and that, sometimes, is more important than the technique affordance. We provided a validation for the distal pointing model through the analysis of expected difficulty of distal pointing tasks in light of each technique tested. We propose selection by progressive refinement, a new design concept for distal pointing selection techniques, whose goal is to offer the ability to achieve near perfect accuracy in selection at very cluttered environments. The idea of selection by progressive refinement is to gradually eliminate possible targets from the set of selectable objects until only one object is available for selection. We implemented SQUAD, a selection by progressive refinement distal pointing technique, and performed a controlled experiment comparing it to basic distal pointing. We found that there is a clear tradeoff between immediate selections that require high precision and selections by progressive refinement which always require low precision. We validated the model by fitting the distal pointing data and proposed a new model, which has a linear growth in time, for SQUAD selection. / Ph. D.

SAAB has a project under development for a network system with connected nodes, where the nodes are both information consumer and producer of different communication types. A node is an equipment or an object that are used by the army e.g. it can be a soldier, military hospital or an UAV. The nodes function as a part of a mission e.g. a mission can be Defend Gotland. The aim of this project is that the user will rank different missions from the one with the highest priority to the lowest. This will affect the network in a way that the communication between the nodes at the mission with the highest rank will be prioritised over the communication between the underlying missions. A user can via the GUI rank the missions, and then set the associated settings for them. Via the GUI the user should be able to work at three different levels. The first is to plan upcoming missions. The second one is in real time see if the system delivers the desired conditions. The last one is to simulate if the system can deliver the desired conditions. This thesis investigated various HCI models that could be used to create a GUI, to reduce the risk of a user configuring the system incorrectly. The study showed that there are no HCI models that take account for misconfigurations, and therefore a new model was created. The new model was used and evaluated by creating a prototype of a GUI for SAAB’s project and was tested on a potential user. The test showed that the new model reduced the risk of misconfigurations. / SAAB har ett projekt för utveckling av ett nätverkssystem med anslutande noder, med noder som kan vara både informationsproducent och konsument för olika kommunikationstyper. En nod är en sak eller ett objekt inom försvaret t.ex. kan det vara en soldat, militärt sjukhus eller en obemannad farkost. Varje nod tillhör ett uppdrag, tex att försvara Gotland. Målet med projektet är att man ska kunna gradera de olika uppdragen och därmed gradera vilken prioritet dessa noder har i nätet. Noder som tillhör ett uppdrag med hög gradering kommer prioriteras över de underliggande uppdragen i nätverket. En användare kan via ett grafiskt användargränssnitt gradera uppdragen och konfigurera tillhörande inställningar. Via det grafiska användargränssnittet kan en användare även planera, gradera och konfigurera inställningar för kommande uppdrag samt simulera om det går att genomföra. Användaren ska även i realtid kunna se om de önskade inställningarna inte kan leva upp till de önskade kraven, och därmed kunna åtgärda detta.  Detta arbete undersökte olika MMI-modeller som kan användas för att skapa ett grafiskt användargränssnitt som minimerar risken att användaren konfigurerar systemet på ett felaktigt sätt. Studien visade sig att det inte finns några MMI modeller som tar hänsyn till felkonfigureringar, och en ny modell skapades. Den nya modellen användes och utvärderas genom att skapa en prototyp av ett grafiskt användargränssnitt för SAAB:s projekt, som testades på en potentiell användare. Testet visade att den nya modellen minskar risken för felkonfigureringar.