No description available.

Tracking the evolution of user interests is a problem instance of concept drift learning. Keeping track of multiple interest categories is a natural phenomenon as well as an interesting tracking problem because interests can emerge and diminish at different time frames. The first part of this dissertation presents a Multiple Three-Descriptor Representation (MTDR) algorithm, a novel algorithm for learning concept drift especially built for tracking the dynamics of multiple target concepts in the information filtering domain. The learning process of the algorithm combines the long-term and short-term interest (concept) models in an attempt to benefit from the strength of both models. The MTDR algorithm improves over existing concept drift learning algorithms in the domain. Being able to track multiple target concepts with a few examples poses an even more important and challenging problem because casual users tend to be reluctant to provide the examples needed, and learning from a few labeled data is generally difficult. The second part presents a computational Framework for Extending Incomplete Labeled Data Stream (FEILDS). The system modularly extends the capability of an existing concept drift learner in dealing with incomplete labeled data stream. It expands the learner's original input stream with relevant unlabeled data; the process generates a new stream with improved learnability. FEILDS employs a concept formation system for organizing its input stream into a concept (cluster) hierarchy. The system uses the concept and cluster hierarchy to identify the instance's concept and unlabeled data relevant to a concept. It also adopts the persistence assumption in temporal reasoning for inferring the relevance of concepts. Empirical evaluation indicates that FEILDS is able to improve the performance of existing learners particularly when learning from a stream with a few labeled data. Lastly, a new concept formation algorithm, one of the key components in the FEILDS architecture, is presented. The main idea is to discover intrinsic hierarchical structures regardless of the class distribution and the shape of the input stream. Experimental evaluation shows that the algorithm is relatively robust to input ordering, consistently producing a hierarchy structure of high quality.

When the case for organizational change is presented as a “vision,” is action to support the change more likely? This notion was tested in two studies in the context of diversity issues at work. Diversity was selected as the context because Canadian workplaces are becoming increasingly diverse, and organizations are confronted with the challenge of addressing diversity issues appropriately and effectively. Moreover, theoretically critical features of visions, such as a connection with personal values, may be present in a vision of diversity. It was hypothesized that a vision—a picture of a desirable future state—may be more effective when it is aligned with individuals’ self interests and personal values. In Study 1, small groups of undergraduate male and female students (N=221) were presented with a vision of a proposed Employment Equity (EE) program that focused on raising women's employment rates. Self-interest was captured in the design as the interaction of participant gender with extent of employment change for women (small vs. large) resulting from the implementation of the EE program. Value orientation was captured by participants’ importance ranking of social justice on a pre-study measure. Verifying the self interest manipulation, men were seen to perceive that this program would influence their career advancement negatively and this effect was significantly stronger in the condition with the large increase in women’s employment. The most striking finding emerged with the three-way interaction between gender, social justice orientation, and the extent of employment change condition as these variables affected participants’ willingness to support the proposed EE program. Men who placed lower value on social justice showed a straightforward self-interest effect, with lowest support for the policy occurring when the increase in the women’s employment rate was greater. In contrast, men with higher social justice value were more favourable toward the policy that produced a greater change in women’s employment rates. For these men, personal values seemed to trump self-interests. Results involving positive affect mirrored the pattern of these results. Compared to a small employment increase for women, a large mandated increase in women’s employment led men who placed lower value on social justice to report feeling less positive. However, men who placed higher value on social justice reported feeling more positive when the mandated increase in women’s employment was large. Study 2 further examined the role of values in responding to a vision involving diversity. It was hypothesized that when values guide behaviour, the underlying motivation is relatively autonomous. That is, instead of yielding to guilt or social pressure, the values-guided person acts to attain identity fulfillment. To investigate this matter, undergraduate students (N=475) were randomly assigned to watch either a visionary presentation about promoting workforce diversity or a business case presentation. The visionary presentation described a prejudice-free, inclusive workplace; the business case covered the legalities of diversity. It was found that participants whose values were diversity-oriented felt more “inspired” than other participants overall, and this effect was significantly stronger in the vision condition. The primary difference in findings between experimental conditions involved the association between a measure of autonomous motivation and participants’ reports of intended action. A positive, significant association was obtained in the vision condition; no significant association was obtained with the business case. These results are understandable from the conditional nature of autonomous motivation as assessed here. That is, in both conditions, some people (i.e., autonomously motivated people) said that if they acted to promote diversity, it would be in order to promote their personal values. However, it was only in the vision condition in which the connection of diversity-promotion action to personal values was made salient. Thus it appears that a vision can influence behaviour by inducing autonomously motivated people to recognize this connection. The vision was not more influential overall in motivating participants to support the proposed cause. Nonetheless results indicated that a vision can be a complementary tool in a diversity change implementation by sparking an interest to act within the right people. Taken together, the findings from these two studies indicate that a key way a vision motivates behaviour is by forging the link between values and a course of action.

No description available.

No description available.

No abstract available. / Thesis (M.A.)-Universty of Natal, Durban, 1982.

No description available.

Historically, “playing hard-to-get” or unclearly expressing interest in a potential romantic partner has been regarded as an effective means to elicit a potential partner’s interest and attraction. This study examined the effects of gender and expressed interest (clear or unclear) on returned interest in potential long-term romantic partners. Male (N = 54) and female (N = 63) undergraduate students were administered a vignette, in which the person expressed either clear or unclear romantic interest in the participant. Results indicated that men were not influence by expressed interest in either condition. In contrast, women responded with significantly greater returned interest in the clearly-expressed interest condition than in the unclearly-expressed interest. This effect may be due to the greater assumed supportiveness and lower relative social-status of the person in the clearly-expressed interest vignette. Implications for gender differences in long-term partner preferences are discussed.

This dissertation looks at various specific applications of stochastic processes in finance. The motivation for this work has been the work on the valuation of the price of an Asian option by Rogers and Shi (1995). Here, we look at functions of integrals of log - Gaussian processes to obtain approximations to the prices of various financial instruments. We look at pricing of bonds and payments contingent on the interest rate. The interest rate is assumed to be log - Gaussian, thus ensuring that it does not go negative. Obtaining the exact price might not be easy in all cases - hence we use of a combination of a conditioning argument and Jensen's inequality to obtain the lower bound to the prices of the bond as well as payments contingent on interest rates. We look at single driver models as well as multi-driver models. We also look at bonds where default is possible. We try to provide a mathematical justification for the choice of the conditioning factor used throughout the thesis to approximate the price of bonds and options. This is similar to the approach used by Rogers and Shi (1995) to valuing an Asian option; but they had provided no mathematical justification. Another part of this dissertation deals with the problem of pricing European call options on stochastically volatile assets. Further, the price and the volatility processes are in general correlated amongst themselves. Obtaining an exact price is quite involved and computation intensive. Most of the previous work in this field has been based on the solution to a system of partial differential equations. As in the case of pricing bonds, here too, we use a conditioning argument to obtain an approximation to the prices. This method is much faster and less computation intensive. We look at the situations of fixed and stochastic interest rates separately and in each case, we look at the volatility process following a simple Brownian motion and an Ornstein Uhlenbeck process. We also look at the value of stop - loss reinsurance contract for the case of a doubly stochastic Poisson process. Finally, we look at an alternative method of pricing bonds and Asian options. This is done by using a direct expansion and thus avoids the numerical integration that is used in the earlier chapters.

The policy instrument of central banks everywhere has usually been a short-term nominal interest rate. This means that central banks have adopted operating procedures whose goal has been to produce some desired level of money market interest rates. Although the Bank of England was in many respects the pioneer of these operating procedures, theoretical and empirical attention has focused almost exclusively on the Federal Reserve. This thesis aims to redress this imbalance by examining - in detail - the sterling money market and the operations of the Bank of England. This task is carried out in two parts. Part I reviews central banks' use of the interest instrument more generally, beginning with an historical sketch of the evolution of central bank money market operations. This sketch is complemented by a critical discussion of two important concepts relating to such operations, namely interest rate smoothing and money base control. A simple analytical model is then developed to illustrate the determination of money market interest rates by the central bank. Part II specifically concerns the money market operations of the Bank of England, and their implications for the behaviour of sterling money market interest rates. First, a model of the term structure of money market interest rates is derived. Its predicted behaviour in reaction to a change in the Bank's official rate is then empirically verified. Next, the yield on eligible bills - the Bank's intervention asset - is examined. It is argued that these assets carry an excess liquidity premium, arising from the Bank's constraints on their issue. Finally, an empirical model of the overnight interest rate - the UK equivalent of the federal funds rate - is developed, and the reasons for its volatility are investigated.