A common problem in data analysis is that the functional form, as well as the parameter values, of the underlying model which should describe a dataset is not known a priori. In these cases some extra uncertainty must be assigned to the extracted parameters of interest due to lack of exact knowledge of the functional form of the model. A method for assigning an appropriate error is presented. The method is based on considering the choice of functional form as a discrete nuisance parameter which is profiled in an analogous way to continuous nuisance parameters. The bias and coverage of this method are shown to be good when applied to a realistic example.

We report a measurement of muon-neutrino disappearance in the T2K experiment. The 295-km muon-neutrino beam from Tokai to Kamioka is the first implementation of the off-axis technique in a long-baseline neutrino oscillation experiment. With data corresponding to 1.43 x 10(20) protons on target, we observe 31 fully-contained single mu-like ring events in Super-Kamiokande, compared with an expectation of 104 +/- 14 (syst) events without neutrino oscillations. The best-fit point for two-flavor nu(mu) -> nu(tau) oscillations is sin(2)(2 theta(23)) = 0.98 and vertical bar Delta m(32)(2)vertical bar = 2.65 x 10(-3) eV(2). The boundary of the 90% confidence region includes the points sin(2)(2 theta(23)), vertical bar Delta m(32)(2)vertical bar = (1.0, 3.1 x 10(-3) eV(2)), (0.84, 2.65 x 10(-3) eV(2)) and (1.0, 2.2 x 10(-3) eV(2)).

The decay time of luminescence from neutral nitrogen-vacancy (NV(0)) centres in synthetic diamond is reported. The intrinsic luminescence lifetime of NV (0) is measured as τ(r) = 19 ± 2 ns. Neutral substitutional nitrogen atoms (N(S)(0)) are shown to quench luminescence from NV(0) by dipole-dipole resonant energy transfer at a rate such that the transfer time would equal τ(r) if one (N(S)(0)) atom was ~3 nm from the NV(0). In chemical-vapour-deposited diamonds grown with a small nitrogen content, that are brown as a result of vacancy-cluster defects, the decay time of NV(0) equals τ(r) in the as-grown material. However, after annealing at ≥1700 °C to remove the brown colour, luminescence from the NV(0) centres is severely quenched. This effect is suggested to be a result of the destruction of NV(0) centres and the creation of new NV(0) centres localized in vacancy-rich regions of the crystals.

The zero-phonon line (ZPL) at 1.68 eV has been attributed to the negatively charged silicon split-vacancy center in diamond, (Si-V)(-), and has been extensively characterized in the literature. Computational studies have predicted the existence of the neutral charge state of the center, (Si-V)(0), and it has been experimentally observed using electron paramagnetic resonance (EPR). However, the optical spectrum associated with (Si-V)(0) has not yet been conclusively identified. In this paper the 1.31 eV band visible in luminescence and absorption is attributed to (Si-V)(0) using an approach which combines optical absorption and EPR measurements. The intensities of both 1.68 eV and 1.31 eV bands are found to increase in deliberately Si-doped chemical vapor deposition (CVD) grown diamond, and also after electron irradiation and annealing, suggesting the involvement of both Si and a vacancy in the centers. The 1.31 eV ZPL is unambiguously associated to Si by its shift to a lower energy when the dominant Si isotope is changed from Si-28 to Si-29. Charge transfer between (Si-V)(-) and (Si-V)(0) induced via ultraviolet photoexcitation or heating in the dark allows calibration factors relating the integrated absorption coefficient of their respective ZPLs to the defect concentration to be determined. Preferential orientation of (Si-V) 0 centers in CVD diamond grown on {110}-oriented diamond substrates is observed by EPR. The (Si-V)(0) centers are shown to grow predominantly into CVD diamond as complete units, rather than by the migration of mobile vacancies to substitutional Si (Si-S) atoms. Corrections for the preferential alignment of trigonal centers for quantitative analysis of optical spectra are proposed and the effect is used to reveal that the 1.31 eV ZPL arises from a transition between the (3)A(2g) ground state and (3)A(1u) excited state of (Si-V)(0). A simple rate equation model explains the production of (Si-V)(0) upon irradiation and annealing of Si-doped CVD diamond. In as-grown Si-doped diamond the (Si-V) defects only account for a fraction of the total silicon present; the majority being incorporated as SiS. The data show that both Si-S and (Si-V) are effective traps for mobile vacancies.

At room temperature, the ν3 (1136 cm − 1) absorption band of oxygen in silicon and Si1 − xGex alloys consists of dozens of components, masking the properties of the individual transitions. Here, experimental data are presented for the evolution of the ν3 band in the temperature range 0 < T < 300 K and the composition range 0 ≤ x ≤ 0.066. The vibrational potential for Si:O is developed to provide accurate fits to the absorption data. The potential predicts properties consistent with published studies, including hydrostatic stress experiments. Extending the model to Si1 − xGex allows the properties of the alloy-induced Oi-I, Oi-II and Oi-III components to be investigated accurately to higher values of x than hitherto. The properties of Oi-I are understood as perturbations by Ge atoms of Si:O, and Oi-III is rationalized in terms of off-axis movement of the O atom resulting from the nearby Ge atom. Challenges to theory are: the behaviour of Oi-II, understanding the strain fields generated by Ge atoms in Si, and the reduced coupling of the ν2 and ν3 modes with increasing amplitude in the ν2 mode.

The (1136-cm(-1)) nu(3) vibration of oxygen in silicon is known to decay at low temperature primarily by emitting two phonons. We show here that the temperature dependence of the decay is caused by a three-phonon process. In both natural-isotope and single-isotope Si-30, the three-phonon process is identified as the emission of one nu(1) (612 cm(-1)) local mode, one nu(2) low-energy local mode, and one lattice mode of 524 cm(-1) (where the quoted values are for O-16 in natural-isotope silicon). The common assumption that the decay of a vibration proceeds through one dominant process is clearly not applicable here.

The transient-bleaching decay time of the ν3 (1136cm−1) band of oxygen in Si1−xGex alloys, at low temperatures, is found to increase rapidly from a few tens of picoseconds when x=0, to 125ps when x is in the range 0.011–0.066. We show that the increased decay time is caused partly by perturbations of the oxygen by the Ge, and partly by the small decrease in the frequencies of the lattice modes in the alloy. The decay time of ν3 in crystalline germanium (x=1) is also ∼115ps, similar to that for the dilute alloys, but it is shown to occur through a different three-phonon process.

The nu(3) (862.5 cm(-1)) vibration of oxygen in crystalline germanium is shown to decay into one nu(1) local mode of the oxygen center plus two lattice modes. This description predicts increases in the linewidths in O-16-doped germanium, and decreases in the linewidths in O-18-doped germanium, as the Ge mass in the Ge-O-Ge complex increases, in agreement with observation. The decay time is expected to vary only slightly with the isotope of oxygen, as observed, and the smallest reported linewidths are consistent with the measured decay times.

This paper introduces a new technique to the study of diamonds: mapping the luminescence lifetime of optical centres. The understanding of luminescence lifetimes in diamond is briefly reviewed. Since lifetime mapping involves extended measuring times with focused laser excitation, the stability of the H3 optical centre is investigated. We show that saturation of the H3 luminescence requires excitation power densities in excess of 10 MW cm(-2). The non-radiative energy transfer time from an H3 centre to an A aggregate is found to be equal to that from N3 centres to A aggregates, at similar to 3 x 10(-16)r(8) s, where there are r bond lengths between the H3 and A centres. Non-radiative energy transfer is shown to occur from the NV- band to the single substitutional nitrogen atoms: the single N atoms may quench luminescence as well as the A aggregates of nitrogen. In contrast, a comparison of the decays from the very similar H3 and H4 centres demonstrates that the B aggregate produces very weak quenching of the visible luminescence from diamond.

This special session will proved information about the status of work related to Masters programs in Computing. Specifically, the session will describe work completed in the following areas: the categorization of masters programs in computing, the development of curriculum recommendations for masters programs in software engineering, the collaborative work with the Association for Information Systems on the Masters program in Information Systems

The ACM Education Board, the Education Activities Board of the IEEE Computer Society, representatives of the Association for Information Systems and the British Computer Society have joined forces to investigate the state of Masters degree programs in computing. This joint effort intends to document the variety and common features of programs throughout the United States and Europe. This poster is a status report on that project and an opportunity for interested individuals to add information about their programs to this work.

Adoption of the Bologna Accord in the European Higher Education Area (EHEA) represents a concerted move towards harmonisation of educational outcomes in higher education at the Bachelor, Masters and PhD levels. At a time when European systems are undergoing significant examination and modification, this project addresses the need for greater understanding of the nature of Masters level education in the Informatics disciplines across Europe and the United States. The poster presents the current findings of the project, and is intended to prompt discussion about the content and expected outcomes of such programmes world-wide.

In this special session, members of the ACM Education Board will give information about two current projects in computer science curriculum developments: an update to the CS2001 volume, CS2008, and a new venture, a report on Masters degrees in Computing. Feedback is required on both reports as the CS2008 volume is an interim measure in advance of a more thorough review in due course. The Masters report will be a report on work-in-progress and feedback on the current progress and the project goals will be welcome.

Working Group 3 at ITiCSE 2007 continued the ongoing work of the Ontology of Computing project. The working group brought several new people into the project and addressed areas of the ontology of particular interest to these participants. In particular, the group worked on the Ontology sections related to History of Computing, Computing Security and Social and Ethical issues. With the intention of applying the ontology to the support of curriculum development in mind, the group also reviewed and discussed proposed means of presenting a visual representation of the ontology. There was also some work on the present structure of the ontology and future possibilities.

The Overview Report of the joint ACM, IEEE-CS, and AIS series on the Computing Curricula was published in 2006. It can be accessed at http://www.acm.org/education/. Its goal is to provide perspective for those in academia who need to understand what the major computing disciplines are and how the respective undergraduate degree programs compare and complement each other. Subsequently, the report has been used as the basis for the production of a brochure to be sent to all US high schools and a web site to support the brochure at which further information relevant to potential students will be found. The aim of both the brochure and supporting web site is to aid recruitment of students in to undergraduate programs in the Computing disciplines. The special session will present both the brochure and the web site, with the intention of seeking feedback to inform future developments, both in the US and UK.

The authors have investigated the effect of Ge concentration on the evolution of W optical center (W center) in Si-implanted epitaxial Si1−xGex at low temperature annealing. From the results of photoluminescence, the annealing behavior of W center can be separated into two regimes, i.e., W centers in Si1−xGex alloy with Ge <5% are stable, otherwise not stable. The annealing behavior of W center is similar to {311} defect in Si1−xGex. It is suggested that the dissipation of excess interstitials by outdiffusion at low temperature is one of the candidate mechanisms for the retardation of transient enhanced diffusion of boron in Si1−xGex.

The Computing Ontology Project, funded in part by the National Science Foundation and with support from the ACM Education Board and the IEEE-CS Education Activities Board, has undertaken to enumerate all of the topics related to any aspect of the computing disciplines. Work of the original committee was enhanced by an ITiCSE working group in 2005. [7]The motivation for this effort includes the immense scale of the task of generating new curriculum recommendations and the difficulty of describing evolving innovative computing programs for purposes of comparison or possible accreditation. The project committee has surveyed lists of computing topics from sources including, but not limited to, the current curriculum recommendations of the ACM, IEEE-CS and AIS. [1, 2, 3, 4, 5] The list also includes topics extracted from the current ACM Computing Classification Scheme. [6] Other topic lists are incorporated as they are discovered.The result is a comprehensive list of computing topics covering all of computer engineering, computer science, information systems, information technology, and software engineering. The committee consists of active educators from each of these areas.A substantial task of the committee has been to merge the topic lists from these diverse areas into a single comprehensive list. While refinement of that merged list continues at the time of submission, a stable representation is nearly complete and its formal representation in the OWL ontology language is underway. By the time of the SIGCSE session, the ontology of computing will be available in a standard format against which a number of applications can be developed for a variety of purposes.