Envisioning human-robot coordination in future operations

Developers of autonomous capabilities underestimate the need for coordination with human team members when their automata are deployed into complex operational settings. Automata are brittle as literal minded agents and there is a basic asymmetry in coordinative competencies between people and automata. The new capabilities of robotic systems raise new questions about how to support coordination. This paper presents a series of issues that demand innovation to achieve human-robot coordination (HRC). These include supporting people in their roles as problem holder and as robotic handler, overcoming ambiguities in remote perception, avoiding coordination surprises by better tools to see into future robotic activities and contingencies, and responsibility in human-robot teams.     

Super-Resolution Based on Fast Registration and Maximum a Posteriori Reconstruction

In this paper, we propose a maximum a posteriori framework for the super-resolution problem, i.e., reconstructing high-resolution images from shifted, rotated, low-resolution degraded observations. The main contributions of this work are two; first, the use of a new locally adaptive edge preserving prior for the super-resolution problem. Second an efficient two-step reconstruction methodology that includes first an initial registration using only the low-resolution degraded observations. This is followed by a fast iterative algorithm implemented in the discrete Fourier transform domain in which the restoration, interpolation and the registration subtasks of this problem are preformed simultaneously. We present examples with both synthetic and real data that demonstrate the advantages of the proposed framework.     

Lucky drift estimation of excess noise factor for conventionalavalanche photodiodes including the dead space effect

A technique for estimating the excess noise factor in conventional avalanche photodiodes has been developed. It is based upon a computer simulation of carrier motion using the lucky drift concept. The importance of the impact ionization dead space is demonstrated, and an established theory is shown to overestimate the excess noise factor due to the neglect of the dead space phenomenon in conventional avalanche photodiodes     

Continuous accountability for acceptable building performance

Complexities in building technology when not fully understood, have resulted in a less than favorable aggregate impact on the building's environment. A surprisingly high portion of U.S. non-industrial buildings do not provide satisfactory task environments. Developments in computer technology have infused new thought processes in the way we plan, design, build and operate our buildings. This paper proposes a social and technical use of Knowledge-based-systems (KBS) for continuous accountability to assure healthy buildings. Diagnostics, as an emerging discipline in building design and operation, is also discussed. A proposed framework for such accountability and the resulting ‘chain of custody’, that draws on the medical paradigm and associated diagnostic procedures is presented. It is suggested that KBS also be used for the development and interpretation of criteria for evaluating building performance from initial conception through design, construction and operation. Thus, KBS is expected to aid in the analysis of ‘virtual’ and ‘actual’ buildings that may be ‘sick’ or ‘healthy’. It is proposed that for a building to provide satisfactory performance over its life-time, the ‘life-cycle’ concept must be modified in terms of the roles, responsibilities, and configuration of the building team, and in terms of its costing procedures.     

Adaptive coding of moving objects for very low bit rates

This paper describes an object-based video coding system with new ideas in both the motion analysis and source encoding procedures. The moving objects in a video are extracted by means of a joint motion estimation and segmentation algorithm based on the Markov random field (MRF) model. The two important features of the presented technique are the temporal linking of the objects, and the guidance of the motion segmentation with spatial color information. This facilitates several aspects of an object-based coder. First, a new temporal updating scheme greatly reduces the bit rate to code the object boundaries without resorting to crude lossy approximations. Next, the uncovered regions can be extracted and encoded in an efficient manner by observing their revealed contents. The objects are classified adaptively as P objects or I objects and encoded accordingly. Subband/wavelet coding is applied in encoding the object interiors. Simulations at very low bit rates yielded comparable performance in terms of reconstructed PSNR to the H.263 coder. The object-based coder produced visually more pleasing video with less blurriness and devoid of block artifacts, thus confirming the advantages of object-based coding at very low bit-rates     

Maximum likelihood parameter estimation of textures using aWold-decomposition based model

We present a solution to the problem of modeling, parameter estimation, and synthesis of natural textures. The texture field is assumed to be a realization of a regular homogeneous random field, which can have a mixed spectral distribution. On the basis of a 2-D Wold-like decomposition, the field is represented as a sum of a purely indeterministic component, a harmonic component, and a countable number of evanescent fields. We present a maximum-likelihood solution to the joint parameter estimation problem of these components from a single observed realization of the texture field. The proposed solution is a two-stage algorithm. In the first stage, we obtain an estimate for the number of harmonic and evanescent components in the field, and a suboptimal initial estimate for the parameters of their spectral supports. In the second stage, we refine these initial estimates by iterative maximization of the likelihood function of the observed data. By introducing appropriate parameter transformations the highly nonlinear least-squares problem that results from the maximization of the likelihood function, is transformed into a separable least-squares problem. The solution for the unknown spectral supports of the harmonic and evanescent components reduces the problem of solving for the transformed parameters of the field to a linear least squares. Solution of the transformation equations then provides a complete solution of the field-model parameter estimation problem. The Wold-based model and the resulting analysis and synthesis algorithms are applicable to a wide variety of texture types found in natural images.     

Chlamydia trachomatis screening in the adolescent population

1. The reproducibility of measurements of the arterial wall thickness in both the carotid and femoral artery was investigated by means of high-resolution B-mode ultrasonography. For this purpose, subjects with normal and increased intima-media thickness were selected. Images were stored on an optical disk and were analysed with a semi-automatic software program by two readers. Individuals were scanned twice by two independent observers. 2. Measurements were performed of the far and near wall of the common carotid artery and bulbous in 30 healthy subjects and 19 patients known to have an increased intima-media thickness. Far-wall measurements were made of the internal carotid artery on both sides and common femoral artery on the right side only. 3. In healthy subjects the mean within-observer coefficient of variation was 1.8% and 3.0% for the far wall in the common carotid artery on the right side and left side, respectively. For the near wall the mean coefficient of variation of the common carotid artery was 2.8% on the right and 3.4% on the left side. The mean coefficient of variation was less than 4% for both far and near wall in the bulbous and far wall in the internal carotid artery. Even in patients with increased intima-media thickness the mean coefficient of variation of each segment was less than 4.5%. In the control subjects the between-observer coefficient of variation of the common carotid artery was 2.8% and 5.1% for the far wall on the right and left side, respectively, and 3.4% and 4.2% for the near wall on the right and left side. In healthy subjects a mean difference of 0.002 mm within observers was found in the right far-wall common carotid artery, with limits of agreement of -0.048 to 0.052 mm. The coefficient of repeatability was 0.050 mm. For patients with increased intima-media thickness the mean difference in this segment was -0.006 mm (-0.094 to 0.082) with a coefficient of repeatability of 0.088 mm. For the near wall in the common carotid artery and far and near wall in the bulbous and internal carotid artery the mean differences were larger, but were all below 0.1 mm. The differences and limits of agreements increased between observers. In patients the between-observer mean difference of the far wall of the common carotid artery was -0.055 mm (-0.255 to 0.145). For the common femoral artery of normal control subjects the within- and between-observer mean differences were 0.005 mm (-0.119 to 0.129) and 0.015 mm (-0.081 to 0.111), respectively. 4. In conclusion, the reproducibility of intima-media thickness measurements in the common carotid artery is reliable, even in patients with increased artery wall thickness. Also in other segments prone to atherosclerosis, such as the bulbous, internal carotid artery and common femoral artery, a good reproducibility was found. To obtain good reproducibility it is highly recommended to use the same ultrasonographer to scan patients in follow-up studies.     

Electron transfer to cytochrome P-450scc limits cholesterol-side-chain-cleavage activity in the human placenta

The aim of this study was to determine whether electron transfer from adrenodoxin reductase and adrenodoxin limits the activity of cytochrome P-450scc in mitochondria from the human placenta. Mitochondria were disrupted by sonication to enable exogenous adrenodoxin and adrenodoxin reductase to deliver electrons to cytochrome P-450scc. After sonication, the rate of pregnenolone synthesis was greatly decreased relative to that by intact mitochondria, due to dilution of endogenous adrenodoxin and adrenodoxin reductase into the incubation medium. The addition of saturating concentrations of bovine or human adrenodoxin and bovine adrenodoxin reductase to the disrupted mitochondria gave an initial rate of pregnenolone synthesis that was 6.3-fold higher than that for intact mitochondria. Similar results were observed when 20alpha-hydroxycholesterol was used as substrate rather than endogenous cholesterol. The turnover number of cytochrome P-450scc in sonicated placental mitochondria supplemented with adrenodoxin and adrenodoxin reductase was comparable to that for the purified enzyme assayed under conditions where electron transfer was not limiting. Addition of exogenous adrenodoxin and adrenodoxin reductase to sonicated mitochondria from the pig corpus luteum and rat adrenal had a much smaller effect on pregnenolone synthesis compared with intact mitochondria, than observed for the placenta. We conclude that in the human placenta, electron transfer to cytochrome P-450scc is limiting, permitting pregnenolone synthesis to proceed at only 16% maximum velocity.