A robust set-valued state estimation approach to the problem of vision based SLAM for mobile robots

The problem of visual simultaneous localization and mapping (SLAM) is examined in this paper using ideas and algorithms from robust control and estimation theory. Using a stereo-vision based sensor, a nonlinear measurement model is derived which leads to nonlinear measurements of the landmark coordinates along with optical flow based measurements of the relative robot-landmark velocity. Using a novel analytical measurement transformation, the nonlinear SLAM problem is converted into the linear filter is guaranteed stable and the ALAM state estimation error is bounded within an ellipsoidal set. No similar results are available for the commonly employed extended Kalman filter which is known to exhibit divergent and inconsistency characteristics in practice.

A robust solution to the stereo-vision-based simultaneous localization and mapping problem with steady and moving landmarks

The problem of visual simultaneous localization and mapping (SLAM) is examined in this paper using recently developed ideas and algorithms from modern robust control and estimation theory. A nonlinear model for a stereo-vision-based sensor is derived that leads to nonlinear measurements of the landmark coordinates along with optical flow-based measurements of the relative robot-landmark velocity. Using a novel analytical measurement transformation, the nonlinear SLAM problem is converted into the linear domain and solved using a robust linear filter. Actually, the linear filter is guaranteed stable and the SLAM state estimation error is bounded within an ellipsoidal set. A mathematically rigorous stability proof is given that holds true even when the landmarks move in accordance with an unknown control input. No similar results are available for the commonly employed extended Kalman filter, which is known to exhibit divergence and inconsistency characteristics in practice. A number of illustrative examples are given using both simulated and real vision data that further validate the proposed method.

The online identity : towards a hermeneutic phenomenological approach

In order to better understand how artists working in countercultural or ‘fringe’ creative practice use social media to create online persona I am using a hermeneutic phenomenological approach to investigate the lived experience of both online and offline persona creation by tattoo artists, street artists, craftivists, and slam poets. The use of phenomenology to investigate artists’ lived experience is particularly appropriate, as ‘artists are involved in giving shape to their lived experience, the products of art are, in a sense, lived experienced transformed into transcended configurations’ (Van Manen 2006: 74). This paper will outline the methodological underpinnings of this project, using these underpinnings to explore the benefits offered by phenomenology to internet studies.

Understanding how people use online social media sites to construct personas can benefit greatly from understanding the lived experience of those who use these technologies, the decisions they make in persona construction, and the online/offline, public/private continuums. A phenomenological approach ‘seeks to revel and richly portray the nature of human phenomena and the experiences of those who live through them’ (Grace & Ajjawi 2010: 197) and offers both the researchers and the participants a way to interrogate and interpret the experience of constructing online personas. A phenomenological approach allows for ‘an intimate awareness and deep understanding’ (Saldana, Leavy & Bertvas 2011: 8) of the experience of persona construction in online and offline spaces, and could equally be used to interrogate other aspects of internet use.