A study on reliability in graph discovery

A critical question in data mining is that can we always trust what discovered by a data mining system unconditionally? The answer is obviously not. If not, when can we trust the discovery then? What are the factors that affect the reliability of the discovery? How do they affect the reliability of the discovery? These are some interesting questions to be investigated.

In this paper we will firstly provide a definition and the measurements of reliability, and analyse the factors that affect the reliability. We then examine the impact of model complexity, weak links, varying sample sizes and the ability of different learners to the reliability of graphical model discovery. The experimental results reveal that (1) the larger sample size for the discovery, the higher reliability we will get; (2) the stronger a graph link is, the easier the discovery will be and thus the higher the reliability it can achieve; (3) the complexity of a graph also plays an important role in the discovery. The higher the complexity of a graph is, the more difficult to induce the graph and the lower reliability it would be.

Valuation and incentive effects of hurdle rate executive stock options

Traditional executive stock options are often criticized for inherently weak links between pay and performance. Hurdle rate executive stock options represent a viable improvement. However, valuing these options presents extraordinary analytic difficulties. With a constant dividend yield the strike price becomes a path-dependent function of the stock price and exact analytic valuation is intractable. To solve this problem, we apply the Monte Carlo valuation approach developed by Longstaff and Schwartz (Rev Financ Stud 4:113–147, 2001) to estimate the value of path-dependent American options. We also extend the methodology to incorporate the theoretical framework by Ingersoll (J Bus 79:453–487, 2006) to permit subjective valuation influenced by an executive’s risk aversion.

Reliable graph discovery

A critical question in data mining is that can we always trust what discovered by a data mining system unconditionally? The answer is obviously not. If not, when can we trust the discovery then? What are the factors that affect the reliability of the discovery? How do they affect the reliability of the discovery? These are some interesting questions to be investigated. In this chapter we will firstly provide a definition and the measurements of reliability, and analyse the factors that affect the reliability. We then examine the impact of model complexity, weak links, varying sample sizes and the ability of different learners to the reliability of graphical model discovery. The experimental results reveal that (1) the larger sample size for the discovery, the higher reliability we will get; (2) the stronger a graph link is, the easier the discovery will be and thus the higher the reliability it can achieve; (3) the complexity of a graph also plays an important role in the discovery. The higher the complexity of a graph is, the more difficult to induce the graph and the lower reliability it would be. We also examined the performance difference of different discovery algorithms. This reveals the impact of discovery process. The experimental results show the superior reliability and robustness of MML method to standard significance tests in the recovery of graph links with small samples and weak links.

Too hot to trot? exploring potential links between climate change, physical activity and health

Based on an analysis of existing literature, this paper explores the links between climate change, physical activity and health. It highlights the importance of physical activity for health, explores current understandings of factors influencing participation in sport and physical activity, and develops some hypotheses about the ways in which climate change may impact on the factors influencing physical activity and thereby on the level of participation in physical activity. The paper argues that climate change has the potential to be a barrier to participation in physical activity, particularly in areas where temperatures are already relatively high, and that a reduction in physical activity across the population is likely to have detrimental health impacts. The need for research to clarify the nature and extent of the threat posed to physical activity participation is highlighted, as is the need to take into account the direct and indirect costs of any changes or reductions in physical activity in any assessment of the costs of climate change and/or its mitigation.

Knowledge management and its links with quality

Knowledge management is a concept that continues to draw a lot of interest. It is the process of sharing knowledge within an organisation to achieve better performance. It can be utilised by all organisations, many of which may not even be aware they are using the concept nor of its links with Quality management. By implementing an effective KM system increased organisational performance and ultimately a competitive advantage can be obtained - both of which correlate to the philosophy of Quality. This paper raises issues about the relationship between the gathering, storing and sharing of knowledge and the philosophy of continuous improvement with the facilitation of teamwork. It concludes by attempting to encourage further debate and research into the area by suggesting that Knowledge Management may be well the 'catalyst' for the resurgence of Quality Management.

Periodic variability in cetacean strandings: links to large-scale climate events

Cetacean strandings elicit much community and scientific interest, but few quantitative analyses have successfully identified environmental correlates to these phenomena. Data spanning 1920–2002, involving a total of 639 stranding events and 39 taxa groups from southeast Australia, were found to demonstrate a clear 11–13- year periodicity in the number of events through time. These data positively correlated with the regional persistence of both zonal (westerly) and meridional (southerly) winds, reflecting general long-term and large-scale shifts in sea-level pressure gradients. Periods of persistent zonal and meridional winds result in colder and presumably nutrient-rich waters being driven closer to southern Australia, resulting in increased biological activity in the water column during the spring months. These observations suggest that large-scale climatic events provide a powerful distal influence on the propensity for whales to strand in this region. These patterns provide a powerful quantitative framework for testing hypotheses regarding environmental links to strandings and provide managers with a potential predictive tool to prepare for years of peak stranding activity.

Geographic routing with cooperative relaying and leapfrogging in wireless sensor networks

A novel geographic routing protocol for multi-hop wireless sensor networks is presented. It exploits the broadcast nature of the wireless channel to enable on-demand cooperative relaying and leapfrogging for circumventing weak radio links. In order to achieve energy efficiency, a metric is introduced for next-hop selection that takes into account information on the residual battery energy, the geographical position of the sensor nodes, and the channel quality of the involved radio links when available. Performance results show that the completely decentralized protocol offers significant benefits by reducing the number of (re)transmissions required to reach the destination. This translates into network-wide energy savings that extend the network lifetime.

New media pathways: navigating the links between home, school, and the workplace

This chapter uses the case of students enrolled in the Multimedia Pathway offered by Harbourside High School to discuss the tensions and contradictions inherent in the views that: (a) school curriculum and pedagogy have much to learn from young people's informal and leisure-based learning; and (b) school-based courses in new media are important because they increase student retention and the chance of success in post-school employment. We draw on literature about the "new work order" (Gee, Hull, & Lankshear, 1996) to explore the nature of these students' learning about and with lCTs and show that the students' knowledge exists "in a network of relationships" (Gee, 2000) that bridge the formal and informal learning divide. Finally, we discuss the parts played by their in- and out-oi-school engagements with lCT in their becoming the kinds of portfolio people supposedly required by the new capitalism.

The evidence that exercise during growth or adulthood reduces the risk of fragility fractures is weak

There has never been, and will never be, a randomized double-blind placebo-controlled trial demonstrating that exercise in youth, adulthood or old age reduces fragility or osteoporosis-related fractures in old age. The next level of evidence, a randomized, controlled but unblinded study with fractures as an end-point is feasible but has never been done. The basis for the belief that exercise reduces fractures is derived from lower levels of ‘evidence’, namely, retrospective and prospective observation cohort studies and case–control studies. These studies are at best hypothesis generating, never hypothesis testing. They are all subject to many systematic biases and should be interpreted with extreme scepticism. Surrogate measures of anti-fracture efficacy are the next level of evidence, such as the demonstration of a reduction in risk factors for falls, a reduction in falls, a reduction in fractures due to falls, an increase in peak bone size and mass, prevention of bone loss in midlife and restoration of bone mass and structure in old age.