On trust and privacy in context-aware systems

Recent advances in networking, handheld computing and sensors technologies have led to the emergence of context-aware systems. The vast amounts of personal information collected by such systems has led to growing concerns about the privacy of their users. Users concerned about their private information are likely to refuse participation in such systems. Therefore, it is quite clear that for any context-aware system to be acceptable by the users, mechanisms for controlling access to personal information are a necessity. According to Alan Westin "privacy is the claim of individuals, groups, or institutions to determine for themselves when, how and to what extent information is communicated to others"1. Within this context we can classify users as either information owners or information receivers. It is also acknowledged that information owners are willing to disclose personal information if this disclosure is potentially beneficial. So, the acceptance of any context-aware system depends on the provision of mechanisms for fine-grained control of the disclosure of personal information incorporating an explicit notion of benefit

Privacy, security, and trust issues in smart environments

Recent advances in networking, handheld computing and sensor technologies have driven forward research towards the realisation of Mark Weiser's dream of calm and ubiquitous computing (variously called pervasive computing, ambient computing, active spaces, the disappearing computer or context-aware computing). In turn, this has led to the emergence of smart environments as one significant facet of research in this domain. A smart environment, or space, is a region of the real world that is extensively equipped with sensors, actuators and computing components [1]. In effect the smart space becomes a part of a larger information system: with all actions within the space potentially affecting the underlying computer applications, which may themselves affect the space through the actuators. Such smart environments have tremendous potential within many application areas to improve the utility of a space. Consider the potential offered by a smart environment that prolongs the time an elderly or infirm person can live an independent life or the potential offered by a smart environment that supports vicarious learning

The SECURE collaboration model

The SECURE project has shown how trust can be made computationally tractable while retaining a reasonable connection with human and social notions of trust. SECURE has produced a well-founded theory of trust that has been tested and refined through use in real software such as collaborative spam filtering and electronic purse. The software comprises the SECURE kernel with extensions for policy specification by application developers. It has yet to be applied to large-scale, multi-domain distributed systems taking different application contexts into account. The project has not considered privacy in evidence distribution, a crucial issue for many application domains, including public services such as healthcare and police. The SECURE collaboration model has similarities with the trust domain concept, embodying the interaction set of a principal, but SECURE is primarily concerned with pseudonymous entities rather than domain-structured systems

The Fragmenting Superbubble Associated with the HII Region W4

New observations at high latitudes above the HII region W4 show that the structure formerly identified as a chimney candidate, an opening to the Galactic halo, is instead a superbubble in the process of fragmenting and possibly evolving into a chimney. Data at high Galactic latitudes (b > 5 degrees) above the W3/W4 star forming region at 1420 and 408 MHz Stokes I (total power) and 1420 MHz Stokes Q and U (linear polarization) reveal an egg-shaped structure with morphological correlations between our data and the H-alpha data of Dennison, Topasna, & Simonetti. Polarized intensity images show depolarization extending from W4 up the walls of the superbubble, providing strong evidence that the radio continuum is generated by thermal emission coincident with the H-alpha emission regions. We conclude that the parts of the HII region hitherto known as W4 and the newly revealed thermal emission are all ionized by the open cluster OCl 352. Assuming a distance of 2.35 kpc, the ovoid structure is 164 pc wide and extends 246 pc above the mid-plane of the Galaxy. The shell's emission decreases in total-intensity and polarized intensity in various locations, appearing to have a break at its top and another on one side. Using a geometric analysis of the depolarization in the shell's walls, we estimate that a magnetic field line-of-sight component of 3 to 5 uG exists in the shell. We explore the connection between W4 and the Galactic halo, considering whether sufficient radiation can escape from the fragmenting superbubble to ionize the kpc-scale H-alpha loop discovered by Reynolds, Sterling & Haffner.Comment: 42 pages, 14 figures; Accepted for publication in Ap

Hyperfine-interaction- and magnetic-field-induced Bose-Einstein-statistics suppressed two-photon transitions

Two-photon transitions between atomic states of total electronic angular momentum $J_a=0$ and $J_b=1$ are forbidden when the photons are of the same energy. This selection rule is analogous to the Landau-Yang theorem in particle physics that forbids decays of vector particle into two photons. It arises because it is impossible to construct a total angular momentum $J_{2\gamma}=1$ quantum-mechanical state of two photons that is permutation symmetric, as required by Bose-Einstein statistics. In atoms with non-zero nuclear spin, the selection rule can be violated due to hyperfine interactions. Two distinct mechanisms responsible for the hyperfine-induced two-photon transitions are identified, and the hyperfine structure of the induced transitions is evaluated. The selection rule is also relaxed, even for zero-nuclear-spin atoms, by application of an external magnetic field. Once again, there are two similar mechanisms at play: Zeeman splitting of the intermediate-state sublevels, and off-diagonal mixing of states with different total electronic angular momentum in the final state. The present theoretical treatment is relevant to the ongoing experimental search for a possible Bose-Einstein-statistics violation using two-photon transitions in barium, where the hyperfine-induced transitions have been recently observed, and the magnetic-field-induced transitions are being considered both as a possible systematic effect, and as a way to calibrate the measurement

A phase I study of the vitamin D analogue EB 1089 in patients with advanced breast and colorectal cancer.

Preclinical studies have shown that the vitamin D analogue EB 1089 has significantly less calcaemic activity than its parent compound 1,25-dihydroxyvitamin D (1,25(OH)2D3) and significant anti-tumour activity. This phase I trial was designed to evaluate the calcaemic effect of the drug in patients with advanced cancer. EB 1089 was given to 36 patients with advanced breast and colorectal cancer in doses of between 0.15 and 17.0 microg m(-2) day(-1). Serial serum and urine calcium, urine creatinine and serum parathyroid hormone (PTH) were monitored. Hypercalcaemia was seen in all patients receiving 17.0 microg m(-2) day(-1). Hypercalcaemia attributable to EB 1089 was reversible by discontinuing or reducing EB 1089 therapy. During the first 5 days of treatment, urine calcium (P = 0.0001) and serum-corrected calcium (P = 0.027) were related to EB 1089 dose, whereas serum parathyroid hormone (P = 0.0001) showed an inverse relationship. Twenty-one patients received compassionate treatment for between 10 and 234 days. No complete or partial responses were seen. Six patients on treatment for more than 90 days showed stabilization of disease. EB 1089 was well tolerated and adverse events considered to be caused by EB 1089 were limited to dose-dependent effects on calcium metabolism. The dose estimated to be tolerable for most patients from this study is around 7 microg m(-2) day(1). These data support previous work that has demonstrated EB 1089 to be significantly less calcaemic than 1,25-dihydroxyvitamin D3

Smoking and prostate cancer: Findings from an Australian case-control study

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The HII Region KR 140: Spontaneous Formation of a High Mass Star

We have used a multiwavelength data set from the Canadian Galactic Plane Survey (CGPS) to study the Galactic HII region KR 140, both on the scale of the nebula itself and in the context of the star forming activity in the nearby W3/W4/W5 complex of molecular clouds and HII regions. From both radio and infrared data we have found a covering factor of about 0.5 for KR 140 and we interpret the nebula as a bowl-shaped region viewed close to face on. Extinction measurements place the region on the near side of its parent molecular cloud. The nebula is kept ionized by one O8.5 V(e) star, VES 735, which is less than a few million years old. CO data show that VES 735 has disrupted much of the original molecular cloud for which the estimated mass and density are about 5000 $M_{\odot}$ and 100 cm$^{-3}$, respectively. KR 140 is isolated from the nearest star forming activity, in W3. Our data suggest that KR 140 is an example of spontaneous (i.e., non-triggered) formation of, unusually, a high mass star.Comment: 46 pages; includes 15 figures; accepted by the Ap

Advanced power sources for space missions

Approaches to satisfying the power requirements of space-based Strategic Defense Initiative (SDI) missions are studied. The power requirements for non-SDI military space missions and for civil space missions of the National Aeronautics and Space Administration (NASA) are also considered. The more demanding SDI power requirements appear to encompass many, if not all, of the power requirements for those missions. Study results indicate that practical fulfillment of SDI requirements will necessitate substantial advances in the state of the art of power technology. SDI goals include the capability to operate space-based beam weapons, sometimes referred to as directed-energy weapons. Such weapons pose unprecedented power requirements, both during preparation for battle and during battle conditions. The power regimes for these two sets of applications are referred to as alert mode and burst mode, respectively. Alert-mode power requirements are presently stated to range from about 100 kW to a few megawatts for cumulative durations of about a year or more. Burst-mode power requirements are roughly estimated to range from tens to hundreds of megawatts for durations of a few hundred to a few thousand seconds. There are two likely energy sources, chemical and nuclear, for powering SDI directed-energy weapons during the alert and burst modes. The choice between chemical and nuclear space power systems depends in large part on the total duration during which power must be provided. Complete study findings, conclusions, and eight recommendations are reported

Long-Term Potentiation: One Kind or Many?

Do neurobiologists aim to discover natural kinds? I address this question in this chapter via a critical analysis of classification practices operative across the 43-year history of research on long-term potentiation (LTP). I argue that this 43-year history supports the idea that the structure of scientific practice surrounding LTP research has remained an obstacle to the discovery of natural kinds