Rethinking the Social Construction of Technology Through 'Following the Actors': A Reappraisal of Technological Frames

In this paper, I summarize case study research on an information system called Connected Kids. This case study was guided by an approach to technology studies called the \'Social construction of technology\' or SCOT Bijker (1984). In discussing Connected Kids, I illustrate many of SCOT\'s main tenents, e.g. the various social interactions that surround and influence technology design. As the paper progresses, however, I focus on one concept in particular, i.e. SCOT\'s notion of a \'technological frame,\' which is used as a catch-all concept for handling the structural influences in technology design. My discussion and illustration of this concept shows that – whilst technological frames help an analyst understand, in general terms, the role structure(s) play in shaping technology – the \'heterogeneity\' of technological frames can cloak the more obvious, and potentially most influential, forces at work in technology design. In the case of Connected kids, the role of resources, and which actors had access to these resources, was critical in pointing Connected Kids down a particular trajectory. Further, this discovery emerged from listening carefully to respondents\' comments on the role of resources in their community. These comments, and my own observations on how resource-access propelled certain actors into a leadership position, led to my developing an alternative method for analyzing technological frames. The implications of this analysis are then discussed within the context of SCOT and technology studies more generally.Social Construction of Technology, Technological Frames, Information Technology

On the de la Garza Phenomenon

DOI: 10.1214/09-AOS787Deriving optimal designs for nonlinear models is, in general, challenging. One crucial step is to determine the number of support points needed. Current tools handle this on a case-by-case basis. Each combination of model, optimality criterion and objective requires its own proof. The celebrated de la Garza Phenomenon states that under a (p − 1)th-degree polynomial regression model, any optimal design can be based on at most p design points, the minimum number of support points such that all parameters are estimable. Does this conclusion also hold for nonlinear models? If the answer is yes, it would be relatively easy to derive any optimal design, analytically or numerically. In this paper, a novel approach is developed to address this question. Using this new approach, it can be easily shown that the de la Garza phenomenon exists for many commonly studied nonlinear models, such as the Emax model, exponential model, three- and four-parameter log-linear models, Emax-PK1 model, as well as many classical polynomial regression models. The proposed approach unifies and extends many well-known results in the optimal design literature. It has four advantages over current tools: (i) it can be applied to many forms of nonlinear models; to continuous or discrete data; to data with homogeneous or nonhomogeneous errors; (ii) it can be applied to any design region; (iii) it can be applied to multiple-stage optimal design and (iv) it can be easily implemented.Supported by NSF Grants DMS-07-07013 and DMS-07-48409. AMS 2000 subject classifications. Primary 62K05; secondary 62J12

The Impact of Corporate Restructuring and Downsizing on the Managerial Careers of Minorities and Women: Lessons Learned from Nine Companies

Glass Ceiling ReportGlassCeilingBackground6ImpactofCorporateDownsizing.pdf: 1346 downloads, before Oct. 1, 2020.0-Pages_from_ImpactofCorporateRestructuringDownsizing.pdf: 87 downloads, before Oct. 1, 2020.1-Appendixfrom_ImpactofCorporateRestructuringDownsizing.pdf: 2958 downloads, before Oct. 1, 2020

Phase-conjugate optical coherence tomography

Quantum optical coherence tomography (Q-OCT) offers a factor-of-two improvement in axial resolution and the advantage of even-order dispersion cancellation when it is compared to conventional OCT (C-OCT). These features have been ascribed to the non-classical nature of the biphoton state employed in the former, as opposed to the classical state used in the latter. Phase-conjugate OCT (PC-OCT), introduced here, shows that non-classical light is not necessary to reap Q-OCT's advantages. PC-OCT uses classical-state signal and reference beams, which have a phase-sensitive cross-correlation, together with phase conjugation to achieve the axial resolution and even-order dispersion cancellation of Q-OCT with a signal-to-noise ratio that can be comparable to that of C-OCT.Comment: 4 pages, 3 figure

Imaging of the Lamina Cribrosa using Swept-Source Optical Coherence Tomography.

The lamina cribrosa (LC) is the presumed site of axonal injury in glaucoma. Its deformation has been suggested to contribute to optic neuropathy by impeding axoplasmic flow within the optic nerve fibers, leading to apoptosis of retinal ganglion cells. To visualize the LC in vivo, optical coherence tomography (OCT) has been applied. Spectral domain (SD)-OCT, used in conjunction with recently introduced enhanced depth imaging (EDI)-OCT, has improved visualization of deeper ocular layers, but in many individuals it is still limited by inadequate resolution, poor image contrast and insufficient depth penetrance. The posterior laminar surface especially is not viewed clearly using these methods. New generation high-penetration (HP)-OCTs, also known as swept-source (SS)-OCT, are capable to evaluate the choroid in vivo to a remarkable level of detail. SS-OCTs use a longer wavelength (1,050 nm instead of 840 nm) compared to the conventional techniques. We review current knowledge of the LC, findings from trials that use SD-OCT and EDI-OCT, and our experience with a prototype SS-OCT to visualize the LC in its entirety. Key Points What is known? •     The LC is the presumed site of axonal injury in glaucoma •     Compared to spectral domain-OCT, enhanced depth imaging-OCT improves imaging of the LC •     Even so, currently used SD-OCT techniques are restricted by poor wavelength penetrance of the deeper ocular layers What our findings add? •    SS-OCT may be a superior imaging modality for deep ocular structures •    Prior studies used SS-OCT to evaluate choroidal thickness in both healthy and 'normal tension glaucoma' eyes •    SS-OCT enables good evaluation of three-dimension (3D) lamina cribrosa morphology. How to cite this article: Nuyen B, Mansouri K, Weinreb RN. Imaging of the Lamina Cribrosa using Swept-Source Optical Coherence Tomography. J Current Glau Prac 2012;6(3): 113-119

Sensitivity advantage of swept source and Fourier domain optical coherence tomography

We present theoretical and experimental results which demonstrate the superior sensitivity of swept source (SS) and Fourier domain (FD) optical coherence tomography (OCT) techniques over the conventional time domain (TD) approach. We show that SS- and FD-OCT have equivalent expressions for system signal-to-noise ratio which result in a typical sensitivity advantage of 20-30dB over TD-OCT. Experimental verification is provided using two novel spectral discrimination (SD) OCT systems: a differential fiber-based 800nm FD-OCT system which employs deep-well photodiode arrays, and a differential 1300nm SS-OCT system based on a swept laser with an 87nm tuning range

Multidimensional en-face OCT imaging of the retina.

Fast T-scanning (transverse scanning, en-face) was used to build B-scan or C-scan optical coherence tomography (OCT) images of the retina. Several unique signature patterns of en-face (coronal) are reviewed in conjunction with associated confocal images of the fundus and B-scan OCT images. Benefits in combining T-scan OCT with confocal imaging to generate pairs of OCT and confocal images similar to those generated by scanning laser ophthalmoscopy (SLO) are discussed in comparison with the spectral OCT systems. The multichannel potential of the OCT/SLO system is demonstrated with the addition of a third hardware channel which acquires and generates indocyanine green (ICG) fluorescence images. The OCT, confocal SLO and ICG fluorescence images are simultaneously presented in a two or a three screen format. A fourth channel which displays a live mix of frames of the ICG sequence superimposed on the corresponding coronal OCT slices for immediate multidimensional comparison, is also included. OSA ISP software is employed to illustrate the synergy between the simultaneously provided perspectives. This synergy promotes interpretation of information by enhancing diagnostic comparisons and facilitates internal correction of movement artifacts within C-scan and B-scan OCT images using information provided by the SLO channel