WiFi-based indoor localization is emerging as a new positioning technology. In this work, we present our efforts to find the best recommender system based on the indoor location tracks collected from the Bow Valley shopping mall for one week. The time a user spends in a shop is considered as an implicit preference and different mapping algorithms are proposed to map the time to a more realistic rating value. A new distribution error metric is proposed to examine the mapping algorithms. Eleven different recommender systems are built and evaluated in terms of accuracy and execution time. The Slope-One recommender system with a logarithmic mapping algorithm is finally selected with a score of 1.292, distribution error of 0.178 and execution time of 0.39 seconds for ten runs.

WiFi-based indoor localization is emerging as a new positioning technology. In this work, we present our efforts to find the best recommender system based on the indoor location tracks collected from the Bow Valley shopping mall for one week. The time a user spends in a shop is considered as an implicit preference and different mapping algorithms are proposed to map the time to a more realistic rating value. A new distribution error metric is proposed to examine the mapping algorithms. Eleven different recommender systems are built and evaluated in terms of accuracy and execution time. The Slope-One recommender system with a logarithmic mapping algorithm is finally selected with a score of 1.292, distribution error of 0.178 and execution time of 0.39 seconds for ten runs.

Objectives. The main objective of the present thesis was to evolve a controlled intermittent velocity field and to examine the impact of this type of dynamic indoor climate on human’s psychology and physiology. The prediction was that intermittent velocity variation could provide occupants with the desired cooling without causing draught and that this intermittent change of the indoor climate would influence peoples’ affect and cognitive performance. Methods. All experiments were performed in a classroom-like environment where groups of subjects were exposed to a temperature increase and step changes in air velocity. The changes or intermittent variations in air velocity consisted of elevated speed during five minutes, which were repeated three times. To reduce the influence of individual thermal preferences all measures were collected twice and the statistical analyses were based on the change scores in these measures. Results. The obtained results showed that, intermittent velocity variation may provide occupants with the desired cooling without causing draught. Subjects exposed to velocity variations were significantly less affected by the temperature rise in the room, compared to the control group. Moreover, the method reduced the expected increase of occupants who perceived the temperature condition as uncomfortable. The findings concerning air movements demonstrate that very few perceived the condition as draughty, after being exposed to the three high velocity pulses. The results concerning affect showed a significant effect on high activation, in the temperature range 21 - 24oC when the velocity variations made the subjects rate the temperature as slightly lowered over time, they kept their level of activation. In the higher temperature interval, 25 - 27oC, unactivated unpleasantness increased and activated pleasantness decreased significantly more in subjects in the constant velocity condition than it did for subjects in the velocity variation condition. In sum, all results concerning affect, the significant ones and tendencies point in the same direction. Subjects exposed to velocity variation report changes, over time, indicating higher activation and more positive feelings. No differences in cognitive performances were shown between the air velocity conditions. However, a tendency to a significant result (p = 0.10) in an attention task was shown, indicating that subjects in the velocity variation condition increased their speed in a short-term memory search, compared to subjects in the constant velocity condition. In the temperature range 21- 24oC, where the perception of the room temperature was measured at 0, 5 and 10 minutes respectively after the last high velocity period, the difference in MTV scores between the two groups, did decrease over time. Ten minutes after the last pulse the difference in MTV scores between the two groups was not significant. This suggests that the high velocity period should be repeated every10 to 15 minutes to keep the expected rise in subjects who judged the thermal conditions as uncomfortable down. The skin temperature was not affected neither by the rise in ambient temperature (from 21 to 24oC over 80 minutes) nor the periods (3 x 5 minutes) of high velocity. A consequence of this result is that the human temperature regulation system permitted an increased heat loss during the high velocity pulse, and hence a reduction of the body’s internal stored heat. For uncovered body parts the increase in heat loss was 20 % during the high velocity pulse. Summarised over the whole exposure time the three pulses produced a total energy loss that was only 2 % higher compared to constant low velocity. / QC 20111221

Thesis (Ph. D.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed February 6, 2008) Includes bibliographical references (p. 140-144).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references. Also available via the Internet.

Thesis (M.S.)--University of Wisconsin -- La Crosse, 1999. / Includes bibliographical references (leaves 37-39).

Thesis (M. Phil.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 110-120).

Thesis (M. Sc.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 85-90).

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 346-351). Available also in a digital version from Dissertation Abstracts.

Dissertation (Ph.D.)--Worcester Polytechnic Institute. / Keywords: Time-of-arrival based ranging, indoor geolocation, cooperative localization, sensor networks, ultra wideband, measurement and modeling, cooperative localization algorithms. Includes bibliographical references (leaves 137-148).