Detection of vehicle occlusion using a generalized deformable model

This paper presents a vehicle occlusion detection algorithm based on a generalized deformable model. A 3D solid cuboid model with up to six vertices is employed to fit any vehicle images, by varying the vertices for a best fit. The advantage of using such a model is that the number of parameterized vertices is small which can be easily deformed. Occlusion is detected by recording the changes in the Area Ratio and the dimensions of the generalized deformable model. Our tests show that the new modeling algorithm is effective in detecting vehicle occlusion.published_or_final_versio

'Undergraduates' expectations of economic and other benefits of higher education : a case study of Hong Kong

Hong Kong started a major expansion of its higher education\ud system in 1989. By 1996, in less than a decade, the student enrolment\ud rate had reached 18% of the relevant age group. Was there a\ud justification for further expansion?\ud This thesis investigates the issue of the demand for higher\ud education from the perspective of the students during the 1 990s, a\ud period of drastic political change and difficult economic conditions. It\ud was an interesting time to explore students' perceptions of economic\ud and other benefits of university education. The assumption was that if\ud students possess positive views of returns from higher education, even\ud in critical periods, their motive for investing in higher education is at\ud least partly instrumental.\ud The findings of the study reveal that students were realistic and\ud informed about the future graduate labour market. They were aware of\ud the financial hardships incurred from the increase in their own share of\ud the cost of higher education, the intensifying competition in the future\ud graduate labour market resulting from education expansion, the\ud possible impact the political changes and the economic downturn after\ud 1997 might have on their future career conditions. Many foresaw and\ud were ready to accept diminishing immediate economic returns upon\ud graduation. Yet most of them still maintained a positive view of long\ud term earnings and career development. Most of them understood that\ud their investment in higher education was a prerequisite for a better\ud future both in economic terms and in terms of life long personal\ud development. All in all, the findings of this study provide evidence to\ud support the instrumentalists' idea, not to exclude the academicians'\ud though, an individual perceives participating in higher education as\ud making investment for his/her future pecuniary returns and/or other\ud benefits

Lorenz energy cycle of the global atmosphere based on reanalysis datasets

The mean state of the global atmospheric energy cycle is re-examined using the two reanalysis datasets — NCEP2 and ERA40 (1979–2001). The general consistency between the two datasets suggests that the present estimates of the energy cycle are probably the most reliable ones. The comparison between the present and a previous study shows noticeable discrepancies in some of the energy components and conversion rates. The current estimate of the transformations from mean potential energy to mean kinetic energy C(P_M, K_M) further suggests that the near-surface processes play an important role in the conversion rate C(P_M, K_M), along with the Ferrel cell and Hadley cells, which probably change the direction of the conversion rate C(P_M, K_M)

Guest editorial : special issue on interaction and experience design

Even in the development of the most technologically complex products, systems and environments, it is now accepted that the role of the user must remain firmly in focus. It is not enough to fulfil functional requirements such as safety and performance, or to achieve technical excellence in manufacture. The emergence of user-centred design has been critical in shifting focus towards human needs in the design and development process. The delivery of more personalized usage scenarios encompasses aspects of interaction design, psychology, culture and human factors to achieve satisfying, engaging and meaningful user experiences. The aim of this special issue is therefore to address the emotional needs of users and their experiences in using products, processes and systems. What indicators can be monitored to best understand response during product use? Do requirements change through the ageing process with respect to motivation, learning and dexterity? How can tasks and activities be designed and sequenced to form compelling narratives of use? How can factors such as culture,personality, experience be considered in interface design? And can the tensions between tailored individual requirements and product universality be resolved in unifying design principles

Thermo-mechanical modeling of a micro-fabricated solid oxide fuel cell

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2004.Includes bibliographical references (p. 77-80).A micro-fabricated solid oxide fuel cell is currently being designed by the Micro-chemical Power Team(funded under the Multidisciplinary University Research Initiative(MURI) Research Program). In the current design a plate structure vital to power generation is exposed to harsh thermal operation conditions, making it susceptible to structural failure. This thesis investigates the mechanisms of its structural failure, develops tools and models to understand the mechanisms quantitatively, and gives suggestions to guide the design process with the models developed. The thesis begins with a brief overview of the principles of fuel cell operation, their associated operating conditions, along with a description of how these conditions may lead to structural failure. Next a representative structure of a portion of a fuel cell critical to power generation is analyzed, for a given temperature distribution. Different temperature distributions across the same structure are also analyzed. Results from these analyses are then used to provide guidance for the design process. Finally future directions for research are given.by Tze Yung Andrew Ie.S.M

Retrieval of Aerosol Optical Depth Under Thin Cirrus from MODIS: Application to an Ocean Algorithm

A strategy for retrieving aerosol optical depth (AOD) under conditions of thin cirrus coverage from the Moderate Resolution Imaging Spectroradiometer (MODIS) is presented. We adopt an empirical method that derives the cirrus contribution to measured reflectance in seven bands from the visible to shortwave infrared (0.47, 0.55, 0.65, 0.86, 1.24, 1.63, and 2.12 m, commonly used for AOD retrievals) by using the correlations between the top-of-atmosphere (TOA) reflectance at 1.38 micron and these bands. The 1.38 micron band is used due to its strong absorption by water vapor and allows us to extract the contribution of cirrus clouds to TOA reflectance and create cirrus-corrected TOA reflectances in the seven bands of interest. These cirrus-corrected TOA reflectances are then used in the aerosol retrieval algorithm to determine cirrus-corrected AOD. The cirrus correction algorithm reduces the cirrus contamination in the AOD data as shown by a decrease in both magnitude and spatial variability of AOD over areas contaminated by thin cirrus. Comparisons of retrieved AOD against Aerosol Robotic Network observations at Nauru in the equatorial Pacific reveal that the cirrus correction procedure improves the data quality: the percentage of data within the expected error +/-(0.03 + 0.05 AOD) increases from 40% to 80% for cirrus-corrected points only and from 80% to 86% for all points (i.e., both corrected and uncorrected retrievals). Statistical comparisons with Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) retrievals are also carried out. A high correlation (R = 0.89) between the CALIOP cirrus optical depth and AOD correction magnitude suggests potential applicability of the cirrus correction procedure to other MODIS-like sensors