Accountability of work activity in high-consequence work systems: human error in context

Organizational context is now accepted as a central concept in attempts to understand error in human–machine systems. However, accounts which emphasize the processes of everyday organizing, such as accountability and work activity, are needed in order to establish organizational requirements for design. In this article, we provide a framework for the consideration of organizational contexts of human error in high-consequence work systems, with a view to integrating empirical insights and supporting practical design work. We draw on computer-supported cooperative work conceptualizations of the process of everyday organizing, particularly the notion of “accountability for work activity” which is pivotal to our organizational account of error. The conceptual framework is characterized here as a set of dimensions which are expressive concerning the relationship between accountability and work activity in different contexts: (1) explicit–implicit; (2) global–local; (3) stable–transient and (4) dependent–independent. The framework is demonstrated with respect to everyday work practices in a radiology department and its analytical utility validated with respect to two documented aviation system failures. Applying the framework has enabled us to identify and define, in terms of the dimensions, a number of contexts for vulnerability in high-consequence systems: contexts for collusion, violation, deference, loss of control, buck passing and complacency. These are discussed in terms of requirements for error-tolerant design. In the final section of the article, links between the various contexts for vulnerability and the design process are explored.     

A single probe fibre optic fluorosensor for marine and freshwater measurements of phytoplankton populations

A white light optical fibre fluorosensor for water quality measurements of the phytoplankton population is reported. The excitation light is amplitude modulated and a phase sensitive detection system is employed. The spectral properties of two typical samples of phytoplankton obtained off the coast of Scotland have been characterised and used in laboratory tests of the fluorosensor. Initial results show that this system is capable of resolving fluorescein concentrations in water of 10^?8mol 1^?1 and phytoplankton populations of 0.1 μgl.     

ON THE PATH PLANNING PROBLEM IN THE VICINITY OF OBSTACLES

This paper presents a new approach to motion planning in the neighborhood of obstacles. The technique presented here, the configuration space vector path planner CSVPP , generates a collision-free path for a robot amongst unknown arbitrarily shaped obstacles. The CSVPP algorithm utilizes discrete vectors in the configuration space of the robot to generate a path between any two points in the robot's dynamic time-varying workspace. The calculation of the robot's path assumes interpolated joint control, and provides a computational speed that enables the algorithm to be implemented in real time. A number of simulations are provided for several varying environments.     

“THERE'S NO PLACE LIKE NEW ORLEANS”: SENSE OF PLACE AND COMMUNITY RECOVERY IN THE NINTH WARD AFTER HURRICANE KATRINA

ABSTRACT: This study contributes to the literature on the strength of place attachment, identity, and dependence in low‐ and moderate‐income neighborhoods. It also engages the literature concerning the role of sense of place in community engagement and the disruption in place attachment, identity, and dependence that natural disasters can cause. By drawing on interview data collected from residents who returned to New Orleans after the storm and from former New Orleanians who evacuated to Houston but did not return, this article investigates the “sense of place” that residents in Ninth Ward New Orleans neighborhoods identify in their narratives about their pre‐ and post‐Hurricane Katrina experiences. The data considered here suggest that returning residents believe that New Orleans in general (and their Ninth Ward neighborhoods in particular) possess a unique bundle of characteristics that, when taken together, cannot be found or replicated elsewhere. While sense of place is an important motivator for returning residents, the data also suggest that complementary factors must be in place if the full potential of this social resource is to be realized.     

Multiphoton effects and electron relaxation times

The formative time that an electron takes to react to stimulus is deduced by a consideration of the multiphoton effect. A similar order of magnitude of the formative time can be obtained from a multiphoton photoconduction experiment. This idea is applied to the electron relaxation effect, in electroluminescence. It is assumed that the electron must spend a formative time in an intermediate level before emitting a photon. This assumption gives a theory in broad accord with a number of luminescence experiments.     

Neutron Scattering Studies of Vitrified Radioactive Waste

The structure of a borosilicate glass containing simulated nuclear waste on a distance scale up to several tens of nanometers was investigated using neutron scattering techniques. Comparison of samples with and without waste suggests that the nature of the basic network of SiO₄ tetrahedra and BO₃ triangles is largely unchanged by addition of the waste. The real-space correlation function for the glass plus waste has clear features at distances below 0.5 nm, which can be attributed to the above network building units. Study of a partially devitrified sample shows diffraction effects due to polycrystalline and vitreous phases. Vitreous and partially devitrified glass containing waste produced a significant amount of small-angle scattering corresponding to regions of inhomogeneity which are 10 nm and larger.