Speckle Statistics in Adaptively Corrected Images

(abridged) Imaging observations are generally affected by a fluctuating background of speckles, a particular problem when detecting faint stellar companions at small angular separations. Knowing the distribution of the speckle intensities at a given location in the image plane is important for understanding the noise limits of companion detection. The speckle noise limit in a long-exposure image is characterized by the intensity variance and the speckle lifetime. In this paper we address the former quantity through the distribution function of speckle intensity. Previous theoretical work has predicted a form for this distribution function at a single location in the image plane. We developed a fast readout mode to take short exposures of stellar images corrected by adaptive optics at the ground-based UCO/Lick Observatory, with integration times of 5 ms and a time between successive frames of 14.5 ms ($\lambda=2.2$ $\mu$m). These observations temporally oversample and spatially Nyquist sample the observed speckle patterns. We show, for various locations in the image plane, the observed distribution of speckle intensities is consistent with the predicted form. Additionally, we demonstrate a method by which $I_c$ and $I_s$ can be mapped over the image plane. As the quantity $I_c$ is proportional to the PSF of the telescope free of random atmospheric aberrations, this method can be used for PSF calibration and reconstruction.Comment: 7 pages, 4 figures, ApJ accepte

Investigating informality in construction: Philosophy, paradigm and practice

The complex interrelationships commonly enacted as a consequence of project team activity take a number of different forms, including those formally dictated by contract conditions. However it is becoming increasingly apparent that project performance is affected by informal relationships, though their investigation is notoriously difficult. This paper proposes that these difficulties arise partly from the nature of the informalities themselves, but also as a consequence of the philosophical position taken by researchers and their consequent methodological/paradigmatic posture, and its impact upon those being studied. It consequently proposes a subjectivist investigative framework that accommodates multiple philosophical points of departure, matching them to a range of alternative methodologies, and indicates the desirability of blending to reflect the peculiarities of each context under investigation. The framework also accommodates the practicalities of putting complex methodologies into action. The paper concludes that this framework presents opportunities to conduct rigorous in-situ investigations of informality at work, leading to authentic and deep insights that would otherwise remain unseen

Identifying the factors that influence innovation championing behaviour in construction support services organisations: a review of the role of middle management

W065 Organisation and Management of Construction Postgraduate Research: Paper ID: 542Innovation has been considered an important means by which organisations seek to achieve advantage over competition and for improving performance in today's highly competitive business environment. A number of factors have been identified as influencing innovation in project-based construction organisations. These include internal factors such as organisational culture, climate, leadership style and exogenous influences such as clients. Although research recognises how important it is for senior management to create an environment conducive to innovation, there is little understanding of how these internal and external factors interact to impact on innovativeness. This paper reviews relevant literature on innovation, organisational culture, organisational climate and leadership style while examining how they combine with external factors to promote innovation in construction support services organisations. The study particularly focuses on the role of key organisational actors with responsibility for developing a climate to facilitate innovation at the divisional or business unit level. The review reveals that efforts to develop a climate that promotes innovation championing behaviour among project managers will be influenced by the organizational culture, leadership style and the extent of external influence on project delivery. The study further reveals the importance of middle managers in promoting innovation. A methodology is presented for examining the role of this key managerial constituency and the ways in which they can enable or impede the innovation process.postprintThe 2010 World Congress of CIB on Building a Better World, University of Salford, Salford, U.K., 10-14 May 2010. In Proceedings: TG65 and W065 - Special Track. 18th CIB World Building Congress, 2010, p. 434-44

Applying a longitudinal tracer methodology to evaluate complex interventions in complex settings

Long-running multi-faceted intervention studies are particularly problematic in large complex organizations where traditional methods prove too resource intensive and can yield inaccurate and incomplete findings. This paper describes the first use of, longitudinal tracer methodology (LTM), a realist approach to evaluation, to examine the links between multiple complex intervention activities (processes) and their outcomes on a construction megaproject. LTM is especially useful when the researcher has little control over intervention delivery but has evidence drawn from multiple sources to evaluate the intervention activities effects over time. This methodology has rarely been deployed in complex organisational settings and not on a construction megaproject. This paper presents a case study of its use over a period of three years, on 24 construction sites forming London’s Thames Tideway Tunnel (Tideway) megaproject. The study examines the ‘transformational’ power of occupational safety and health (OSH) interventions across the multiple organisations and supply chains in the megaproject. The study shows how the method can be adapted in-flight to accommodate shifting lines of inquiry as the intervention activities progress and change. This feature along with its resource efficient operation, make it any attractive option where interventions are likely to have differential effects across multiple sites of enactment

Analisis Peluang Curah Hujan Untuk Penetapan Pola Dan Waktu Tanam Serta Pemilihan Jenis Komoditi Yang Sesuai Di Desa Masbagik Kecamatan Masbagik Kabupaten Lombok Timur

Climatic factor, such as rainfall, greatly contributes to the availability of water for crops. Farmers set a schedule and cropping patterns based on habits, such as the period of rainy month. This method is lack precision on determining crops pattern and often increasing the risk of crop failure. This study aims to determine rainfall probability in Masbagik village on growing season of 2015-2016. Research method was descriptive analytical method. Results of this research revealed that the general rainfall pattern of the study area was still following general pattern of the previous year. Rain probability that approached natural precipitation at the field of study was 50%, with the highest limits at December by 304.5 mm and the lowest at October by 37 mm, while general rainfall probability was normal. Rainy season was predicted to start at mid-November and end at early June, while dry season occurs from early May and end in early November. Recommended scenario of the first growing season for the crop is starting at mid-November until the end of February and the second growing season start at mid-March until June 2015. Moreover, planting time for growing rice can be carried out at mid-October, while from early March growing crops is more suitable. Keywords: rainfall, type of commodity, cropping pattern &nbsp

Electrically pumped semiconductor laser with low spatial coherence and directional emission

We design and fabricate an on-chip laser source that produces a directional beam with low spatial coherence. The lasing modes are based on the axial orbit in a stable cavity and have good directionality. To reduce the spatial coherence of emission, the number of transverse lasing modes is maximized by fine-tuning the cavity geometry. Decoherence is reached in a few nanoseconds. Such rapid decoherence will facilitate applications in ultrafast speckle-free full-field imaging