shortend

tex/chapters/relatedwork.tex

@@ -11,7 +11,7 @@ use signal strength prediction models like the log-distance or wall-attenuation-
 Additionally, the sensors noise is not always Gaussian or satisfies the central limit theorem. Using
 Kalman filters is therefore problematic \cite{sarkka2013bayesian, Nurminen2014}.
 All this shows, that sensor models differ in many ways and are a subject in itself.
-A good discussion on different sensor models can be found in \cite{Yang2015}, \cite{Gu2009} or \cite{Khaleghi2013}. 
+A good discussion on different sensor models can be found in \cite{Yang2015} or \cite{Khaleghi2013}. 
 
 However, within this work, we use simple models, configured using a handful of empirically chosen parameters and
 address their inaccuracies by harnessing prior information like the pedestrian's desired destination. Therefore,
@@ -21,7 +21,7 @@ on the state transition and how to incorporate environmental and navigational kn
 A widely used and easy method for modelling the movement of a pedestrian, is the prediction of a new position
 using both, a walking direction and a to-be-walked distance, starting from the previous position.
 If the line-of-sight between the new and the old position intersects a wall, the probability for this
-transition is set to zero \cite{Woodman08-PLF, Blanchert09-IFF, Koeping14-ILU}.
+transition is set to zero \cite{Blanchert09-IFF, Koeping14-ILU}.
 However, as \cite{Nurminen13-PSI} already stated, it "gives more probability to a short step".
 An additional drawback of these approaches is that for every transition an intersection-test
 must be executed and thus often yields a high computational complexity.
@@ -34,15 +34,12 @@ It represents the topological skeleton of the building's floorplan as an irregul
 This drastically removes degrees of freedom from the map, and results in a low complexity.
 
 In the work of \cite{Nurminen2014} a Voronoi diagram is used to approximate the human movement. 
-It is assumed that the pedestrian can be anywhere on the topological links.
+It is assumed that the user can be anywhere on the topological links.
 The probabilities of changing to the next link are proportional to the total link lengths.
-However, for highly accurate localisation in large-scale buildings, this network of one-dimensional
-curves is not suitable \cite{Afyouni2012}.
-Therefore, \cite{Hilsenbeck2014} searches for large open spaces (e.g. a lobby) and extends the Voronoi diagram
-by adding those two-dimensional areas.
-The final graph is then created by sampling nodes in regular intervals across the links and filling up the open
-spaces in a tessellated manner.  Similar to \cite{Ebner-15}, they provide a state transition model that selects
-an edge and a node from the graph according to a sampled distance and heading. 
+However, for accurate localisation in large-scale buildings, this network of one-dimensional curves is not suitable \cite{Afyouni2012}.
+Therefore, \cite{Hilsenbeck2014} searches for large open spaces (e.g. a lobby) and extends the Voronoi diagram by adding those two-dimensional areas.
+The final graph is then created by sampling nodes in regular intervals across the links and filling up the open spaces in a tessellated manner.  
+Similar to \cite{Ebner-15}, they provide a transition model that selects an edge and a node from the graph according to a sampled distance and heading. 
 
 Nevertheless, most corridors are still represented by just one topological link. 
 While the complexity is reduced, it does not allow arbitrary movements and leads to suboptimal trajectories. 
@@ -74,7 +71,7 @@ An additional smoothing procedure is performed to make the path more natural.
 They are considering foot span, body dimensions and obstacle dimensions when determining whether an obstacle is surmountable. 
 However, many of this information is difficult to ascertain in real-time or imply additional effort in real-world environments. 
 Therefore, more realistic simulation models, mainly for evacuation simulation, are just using a simple shortest path on regularly
-tessellated graphs \cite{Sun2011, tan2014agent}. A more costly, yet promising approach is shown by \cite{Brogan2003}. They use a
+tessellated graphs \cite{tan2014agent}. A more costly, yet promising approach is shown by \cite{Brogan2003}. They use a
 data set of previously recorded walks to create a model of realistic human walking paths. 
 
 Finally, it seems that currently none of the localisation system approaches are using realistic walking paths as additional