http://dspace.cityu.edu.hk:80 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. 2013-06-16T16:39:40Z http://dspace.cityu.edu.hk:80/handle/2031/174 Title: S.P.A.C.E Authors: Lai, Alice Yee Man (賴綺雯) 2003-03-01T00:00:00Z http://dspace.cityu.edu.hk:80/handle/2031/337 Title: Hedonic pricing in property sales and property rent Authors: Chan, Tsz Kin (陳子健); Cheng, Chung Hon (鄭忠漢) Abstract: This study applies the hedonic pricing model to Property Sales and Property Rent and the aim is to investigate whether the Property Sales and Property Rent are affected by different factors. Two log forms of hedonic pricing models, with the same set of independent variables, are applied to Property Sales and Property Rent. The quantitative variables in our dataset are “Gross Area” and “Building Age” of a property and the dummy variables are defined to represent different qualitative attributes of the property in order to test if the attributes are considered as significant factors of Sales and Rent. In conclusion, the positive common factors are “Gross Area”, “Sea View” and “MTR/KCR”. The three negative common factors are “Building Age”, “No. of Flats in the Building” and “No. of Bus/Minibus Routes”. On the other hand, the positive specific factor, for Sales is “High Level of Floor”, while the two positive specific factors for Rent are “South Direction” and “No. of Band 1 Schools” in the district of the property. 2004-01-01T00:00:00Z http://dspace.cityu.edu.hk:80/handle/2031/7013 Title: Impact of antenna correlation on multi-user MIMO systems Authors: Wang, Hao (汪浩) Abstract: Multiple-input multiple-output (MIMO) techniques provide a promising solution to enhance the performance of wireless communication systems. Antenna correlation exists in practical MIMO systems for two reasons. First, there may be no sufficient space to separate antenna elements due to the limited physical sizes of the transmitters and/or the receivers. Second, the practical propagation environments may not provide sufficient scatters. In a conventional single-user MIMO system, since antenna correlation results in reduced degrees of freedom (DOF) and may severely degrade the system capacity, it has been generally regarded as a negative factor. However, the impact of antenna correlation in multi-user environments is still limited explored. In this thesis, we make a comprehensive study on theoretical and practical aspects of multi-user MIMO systems with correlated fading. In the first contribution, the capacity of correlated MIMO systems with full channel state information (CSI) at both the transmitters and the receiver over multiple access channels (MACs) (i.e. uplink multi-user MIMO systems) is analyzed. In contrast to the common views, we show that antenna correlation is potentially beneficial in a multi-user environment. The key is that the spatial diversity related to user locations (i.e., multi-user diversity) can compensate the loss of DOF due to antenna correlation. More specifically, it is shown numerically that there is a cross point between the capacity curves for systems with and without correlation. Below this point, correlation is advantageous and vice versa. Moreover, such a point occurs at a rate increasing with the number of mobile units (MUs) (denoted by K in this thesis), which implies that the range where antenna correlation is beneficial increases with K. We also quantify this advantage analytically in the limiting case of K → ∞. In the meanwhile, it is shown numerically and analytically that there is a similar advantage from antenna correlation for MIMO MACs with rate constraints. (We call this advantage correlation gain in this thesis.) In the second contribution, we study the impact of antenna correlation on the capacity of MIMO MACs with imperfect CSI at the transmitter (CSIT). We first consider the case of no CSIT.We prove that isotropic inputs (i.e., the covariance of transmitted signal for each MU is identity matrix) are the most robust and optimal ones, and therefore achieve the capacity of such systems. Both numerical results and theoretical analysis show that although antenna correlation is detrimental in all rate or power range, the capacity degradation decreases with K increasing and vanishes when K → ∞. These results imply that besides multi-user diversity, CSIT also plays an important role in exploiting correlation gain. We then study the systems with partial CSIT in form of channel covariance information (CCI). Our major finding is that, similar to the scenario of perfect CSIT, antenna correlation is potentially beneficial in a multi-user environment. We also prove that, when antennas at MUs are fully correlated, systems with CCI at transmitters can obtain exact the same correlation gain as that in systems with perfect CSIT. This indicates that CCI may be enough to exploit the potential benefit of antenna correlation. In the third contribution, we extend the results from the MAC scenario to the broadcast channel (BC) scenario (i.e., downlink multi-user MIMO systems). Numerical results show that, similar to MIMO MACs, antenna correlation can potentially improve the capacity of MIMO BCs. We point out that, besides multiuser diversity and power focusing effect, such a gain mainly comes from the fact that antenna correlation can increase the variance of the channel gain, which has already been regarded as a advantageous factor in systems with user scheduling. We also quantify the correlation gain in BCs for the limiting case of K → ∞ when antennas at the base station (BS) and/or MUs are fully correlated. Theoretical analysis shows that the asymptotic correlation gain for the case of full correlation at both the BS and MUs grows linearly and logarithmically with the antenna number at the BS, and logarithmically with the antenna number at each MU. In the final contribution, we consider the practical implementation aspects of correlation gain in coded MIMO multiple-access systems. To decrease the complexity of MIMO transmission under imperfect CSIT, we propose two types of low-cost but asymptotically optimal strategies, i.e. the instantaneous maximum eigenmode beamforming (MEB) and statistical MEB strategy. Interleave-division multiple-access (IDMA) technique, as a low-cost iterative multi-user detection (MUD) approach, is adopted to alleviate inter-user interference resulting from multi-user concurrent transmission. Simulation results demonstrate that our proposed transceiver (i.e., MEB-based IDMA system) is an effective platform in practice to obtain the aforementioned correlation gain. In summary, this thesis presents a comprehensive study on antenna correlation in multi-user MIMO systems. Both numerical and analytical results show that antenna correlation is potential advantageous in a multi-user environment. Such an advantage mainly comes from three aspects. First, the loss of the spatial DOF due to antenna correlation is compensated by multi-user diversity. Second, antenna correlation enables focusing power. Third, the variance of the channel gain is enlarged by antenna correlation, which is beneficial in systems with user scheduling. The finding in this thesis is useful in practice as minimizing the physical size of MUs and/or the BS is highly desirable, but it may result in antenna correlation. Notes: CityU Call Number: TK5103.4836 .W36 2012; xi, 91, iii leaves : ill. 30 cm.; Thesis (Ph.D.)--City University of Hong Kong, 2012.; Includes bibliographical references (leaves [83]-91) 2012-01-01T00:00:00Z http://dspace.cityu.edu.hk:80/handle/2031/7012 Title: Culture and experience : Chinese and Americans judgment about experience-related issues Authors: Jiang, Feng (姜峰) Abstract: Human experience is the crucial connection of the outer world and inner world, as well as the important foundation of human existence. Although experience happens almost every day, it has been overlooked by psychologists for a long time. Regarding this issue, a series questions can be asked for psychologists: Do we prefer to cope with new situations by consulting prior experience or depending upon exploratory approach? What is the reason for adopting certain strategies? Is our cultural background involved? In this dissertation, Chinese and American psychological approaches to experience were differentiated in terms of reflective orientation versus exploratory orientation. Chinese ways of understanding experience - considering it as a rigid or closed entity that should always be obeyed and abided by, result in a reflective approach. In contrast, American ways of understanding experience - regarding it as a tool or method to explore the unknown world and to obtain knowledge, result in an exploratory approach. This dissertation builds on four studies conducted to test our contention and results are as follows. Chinese preferred reflective proverbs that emphasize the importance of experiences whereas Americans preferred exploratory proverbs that stress on the importance of exploration (Study 1). Chinese were more likely to attribute their success or achievement to experiences whereas Americans were more likely to attribute it to their exploration (Study 2). Chinese tended to evaluate the reflective-oriented values more important whereas American tended to evaluate the exploratory-oriented values more important (Study 3). Chinese prediction was more easily influenced by prior information whereas Americans prediction was immune to prior information (Study 4). Implications and future direction about the reflective-exploratory orientations are discussed. Notes: CityU Call Number: BF637.E97 J63 2012; vi, 118 leaves 30 cm.; Thesis (Ph.D.)--City University of Hong Kong, 2012.; Includes bibliographical references (leaves 88-103) 2012-01-01T00:00:00Z