Detection rates for abnormal cervical smears: what are we screening for?

We analysed rates of detection for smear abnormalities in 255,000 women served by the Bristol screening programme. The programme began in 1966 with the aim of eradicating the 30-40 deaths each year in Bristol from cervical cancer. Organisation has been good and population uptake has been high for the past 15 years. Records were computerised in 1977. During the 1988 to 1993 screening round, 225,974 women were tested. New smear abnormalities were found in 15,551, of whom nearly 6000 were referred for colposcopy. These numbers are excessively high in comparison with the incidence of the malignancy we are trying to prevent. The effect of screening on death rates in Bristol is too small to detect. Our conclusion is that despite good organisation of the service, much of our effort in Bristol is devoted to limiting the harm done to healthy women and to protecting our staff from litigation as cases of serious disease continue to occur. The real lesson from 30 years' cervical screening is that no matter how obvious the predicted benefit may seem for any screening test, introduction should never take place without adequate prior evaluation of both positive and negative effects in controlled trials.     

On tool wear and its effect on machined surface integrity

This paper presents the results of an investigation of induced residual stress, induced strain, and induced subsurface energy in machined surfaces due to the machining process. The influence of tool wear on residual stress, strain, and energy is also reported. The exact elasticity solution for a split ring was extended and used to calculate the residual stress in the machined surface by using ring dimension changes caused by the electrochemical removal of a thin layer of residually stressed surface. The strain distribution beneath the machined surface was determined by using the grid technique. The subsurface energy stored in the machined surface was then obtained from the data of residual stress and strain. For the materials studied, this investigation showed that such energy could not be neglected when establishing the total energy needed for machining a unit volume of material. Tool coatings having different surface roughness and tools having various magnitudes of flank wear were investigated. The experimental results show that tool wear is a dominant factor affecting the values of induced residual stress, strain, subsurface energy, and the quality of the machined surface. The increase of tool wear caused an increase of residual stress and strain beneath the machined surface. It was also found that the overall energy stored in the machined subsurface increases as the tool wear increases and as the tool surface gets rougher. When the cutting tool is severely worn, the machined surface not only becomes very rough, but also contains many partially fractured laps or cracks. This makes tool wear a key factor in controlling the quality of the machined surface.     

Project failure <Emphasis Type="Italic">en masse</Emphasis>: a study of loose budgetary control in ISD projects

This paper investigates the tightness of budgetary control over projects in a large systems development multinational. This represents a case of extreme information systems development (ISD) failure en masse, where all but two of the 22 projects in a business unit went over budget, causing senior executives to refocus their strategic priorities and cancel all current and potential projects that followed. This study focuses specifically on the two best performing (12 and 4% under budget) and worst performing (223 and 320% over budget) of these projects. Using a framework drawn from control systems theory, this study examines the ‘tightness’ of budgetary control exerted over each project, and what was done or could have been done to avert such failure. The study then identifies a set of emerging factors affecting tight budgetary control in ISD.     

The between-day and inter-rater reliability of a novel wireless system to analyse lumbar spine posture

Lumbar posture is commonly assessed in non-specific chronic low back pain (NSCLBP), although quantitative measures have mostly been limited to laboratory environments. The BodyGuard? is a spinal position monitoring device that can monitor posture in real time, both inside and outside the laboratory. The reliability of this wireless device was examined in 18 healthy participants during usual sitting and forward bending, two tasks that are commonly provocative in NSCLBP. Reliability was determined using intraclass correlation coefficients (ICC), the standard error of measurement (SEM), the mean difference and the minimal detectable change (MDC90). Between-day ICC values ranged from 0.84 to 0.87, with small SEM (5%), mean difference (<9%) and MDC90 (<14%) values. Inter-rater ICC values ranged from 0.91 to 0.94, with small SEM (4%), mean difference (6%) and MDC90 (9%) values. Between-day and inter-rater reliability are essential requirements for clinical utility and were excellent in this study. Further studies into the validity of this device and its application in clinical trials in occupational settings are required. STATEMENT OF RELEVANCE: A novel device that can analyse spinal posture exposure in occupational settings in a minimally invasive manner has been developed. This study established that the device has excellent between-day and inter-rater reliability in healthy pain-free subjects. Further studies in people with low back pain are planned.     

Computer chess move-ordering schemes using move influence

The chessmaps heuristic is a pattern-oriented approach to ordering moves for the game of chess. It uses a neural network to learn a relation between the control of the squares and the influence of a move. Depending on what squares a player controls, the chessmaps heuristic tries to determine where the important areas of the chessboard are. Moves that influence these important areas are then ordered first. The heuristic has been incorporated into a move-ordering algorithm that also takes account of immediate tactical threats. Human players also rely strongly on patterns when selecting moves, but would also consider immediate tactical threats, so this move-ordering algorithm is an attempt to mimic something of the human thought process when selecting a move. This paper presents a new definition for the influence of a move, which improves the performance of the heuristic. It also presents a new experience-based approach to determining what areas of the chessboard are important, which may actually be preferred to the chessmaps heuristic. The results from game-tree searches suggest that the move-ordering algorithm could compete with the current best alternative of using the history heuristic with capture moves in a brute-force search.     

Store-and-Forward Multicast Routing on the Mesh

We study the complexity of routing a set of messages with multiple destinations (multicast routing) on an n-node square mesh under the store-and-forward model. A standard argument proves that time is required to route n messages, where each message is generated by a distinct node and at most c messages are to be delivered to any individual node. The obvious approach of simply replicating each message into the appropriate number of unicast (single-destination) messages and routing these independently does not yield an optimal algorithm. We provide both randomized and deterministic algorithms for multicast routing, which use constant-size buffers at each node. The randomized algorithm attains optimal performance, while the deterministic algorithm is slower by a factor of O( log ² n). We also describe an optimal deterministic algorithm that, however, requires large buffers of size O(c). A preliminary version of this paper appeared in Proceedings of the 13th Annual ACM Symposium on Parallel Algorithms and Architectures, Crete, Greece, 2001. This work was supported, in part, by MIUR under project ALGO-NEXT.     

Customising agile methods to software practices at Intel Shannon

Tailoring of methods is commonplace in the vast majority of software development projects and organisations. However, there is not much known about the tailoring and engineering of agile methods, or about how these methods can be used to complement each other. This study investigated tailoring of the agile methods, eXtreme programming (XP) and Scrum, at Intel Shannon, and involved experienced software engineers who continuously monitored and reflected on these methods over a 3-year period. The study shows that agile methods may individually be incomplete in supporting the overall development process, but XP and Scrum complement each other well, with XP providing support for technical aspects and Scrum providing support for project planning and tracking. The principles of XP and Scrum were carefully selected (only six of the 12 XP key practices were implemented, for example) and tailored to suit the needs of the development environment at Intel Shannon. Thus, the study refutes the suggestion that agile methods are not divisible or individually selectable but achieve their benefits through the synergistic combination of individual agile practices; rather, this study shows that an a la carte selection and tailoring of practices can work very well. In the case of Scrum, some local tailoring has led to a very committed usage by developers, in contrast to many development methods whose usage is limited despite being decreed mandatory by management. The agile practices that were applied did lead to significant benefits, including reductions in code defect density by a factor of 7. Projects of 6-month and 1-year duration have been delivered ahead of schedule, which bodes well for future ability to accurately plan development projects.     

Load relaxation in aluminum: I. Theory of plastic deformation. II. Plastic equation of state

According to the theory of thermally-activated deformation, the plastic strain rate equality will hold in a load relaxation experiment, wheret = 0 is de-fined as the time at which the crosshead stops. In this theory, plastic flow is intrinsically time dependent and its rate is controlled by interaction of glide dislocations with thermal obstacles(e.g. forest dislocations). The strain rate equation is of the form and att = 0 none of these variables changes instantaneously. Measurements reported here for [111] aluminum single crystals indicate that this prediction is wrong. The ratio is near zero at low stress and approaches unity only at high stress. This result is predicted if plastic strain itself is time-independent (athermal), as in the author’s recent theory. Time-dependent strain is then the result of thermal changes in structure, namely loss (recovery) and rearrangement of obstacle dislocations. Experi-ments were also done to test further the essential hypothesis of Hart’s recent formula-tion of an equation of state for plastic deformation-namely that each distinct σ-@#@ curve derived from load relaxation data corresponds to a unique “hardness” state and that re-covery does not occur. Significant differences were observed in the 77 K strsss-strain curves for 295 K relaxed and unrelaxed samples which indicate that substantial loss and some rearrangement of dislocations has occurred during the relaxation. It is concluded from both experiments that load relaxation in aluminum is a manifestation of recovery creep and cannot be taken as evidence for a plastic equation of state.     

“Leagile” software development: An experience report analysis of the application of lean approaches in agile software development

In recent years there has been a noticeable shift in attention from those who use agile software development toward lean software development, often labelled as a shift “from agile to lean”. However, the reality may not be as simple or linear as this label implies. To provide a better understanding of lean software development approaches and how they are applied in agile software development, we have examined 30 experience reports published in past agile software conferences in which experiences of applying lean approaches in agile software development were reported. The analysis identified six types of lean application. The results of our study show that lean can be applied in agile processes in different manners for different purposes. Lean concepts, principles and practices are most often used for continuous agile process improvement, with the most recent introduction being the kanban approach, introducing a continuous, flow-based substitute to time-boxed agile processes.