An empirical investigation of an object-oriented software system

This is the post print version of the article. The official published version can be obtained from the link below.This paper describes an empirical investigation into an industrial object-oriented (OO) system comprised of 133,000 lines of C++. The system was a subsystem of a telecommunications product and was developed using the Shlaer-Mellor method. From this study, we found that there was little use of OO constructs such as inheritance and, therefore, polymorphism. It was also found that there was a significant difference in the defect densities between those classes that participated in inheritance structures and those that did not, with the former being approximately three times more defect-prone. We were able to construct useful prediction systems for size and number of defects based upon simple counts such as the number of states and events per class. Although these prediction systems are only likely to have local significance, there is a more general principle that software developers can consider building their own local prediction systems. Moreover, we believe this is possible, even in the absence of the suites of metrics that have been advocated by researchers into OO technology. As a consequence, measurement technology may be accessible to a wider group of potential users

Some First Results for Noncooperative Pregames : Social Conformity and Equilibrium in Pure Strategies.

We introduce the framework of noncooperative pregames and demonstrate that for all games with sufficiently many players, there exists approximate (E) Nash equilibria in pure strategies. Moreover, an equilibrium can be selected with the property that most players choose the same strategies as all other players with similar attributes. More precisely, there is an integer K, depending on E but not on the number of players so that any sufficiently large society can be partitioned into fewer than K groups, or cultures, consisting of similar players, and all players in the same group play the same pure strategy. In ongoing research we are extending the model to cover a broader class of situations, including incomplete information.GAMES ; INFORMATION ; STRATEGIC PLANNING

Examining the relationship between pubertal stage, adolescent health behaviours and stress

Background. This paper examines the associations between puberty and three important health behavlours (smoking, food intake and exercise) and explores whether these associations are mediated by puberty's relationship to stress and psychological difficulties.Method. Data were taken from the first year of the ongoing, 5-year, Health and Behaviours in Teenagers Study (HABITS). This is a school-based study set in 36 schools in London. In the first year of the study, 4320 students (2578 boys, 1742 girls) in their first year of secondary education took part.Results. Among girls, being more pubertally advanced was associated with a greater likelihood of having tried smoking. Among boys, being more pubertally advanced was associated with a greater likelihood of having tried smoking, a higher intake of high-fat food and higher levels of exercise. More pubertally advanced girls experienced more stress but not more psychological difficulties. There were no associations between puberty and either stress or psychological difficulties in boys. Stress and psychological difficulties were associated with health behaviours in girls and boys, but neither of these factors mediated the relationship between pubertal stage and health behaviours found in girls.Conclusions. These results suggest that the onset of puberty has a marked effect on the development of health behaviours. Puberty was related to an acceleration of the development of unhealthy behaviours, except for exercise behaviour in boys, where advanced puberty was associated with more exercise. These changes were unrelated to adolescent issues of stress and a causal explanation for these associations must be sought elsewhere

Does micro-credit empower women : evidence from Bangladesh

This paper examines the effects of men's and women's participation in group-based micro-credit programs on a large set of qualitative responses to questions that characterize women's autonomy and gender relations within the household. The data come from a special survey carried out in rural Bangladesh in 1998-99. The results are consistent with the view that women's participation in micro-credit programs helps to increase women's empowerment. Credit program participation leads to women taking a greater role in household decisionmaking, having greater access to financial and economic resources, having greater social networks, having greater bargaining power compared with their husbands, and having greater freedom of mobility. Female credit also tended to increase spousal communication in general about family planning and parenting concerns. The effects of male credit on women's empowerment were, at best, neutral, and at worse, decidedly negative. Male credit had a negative effect on several arenas of women's empowerment, including physical mobility, access to savings and economic resources, and power to manage some household transactions.Public Health Promotion,Economic Theory&Research,Health Monitoring&Evaluation,Anthropology,Environmental Economics&Policies,Health Monitoring&Evaluation,Anthropology,Environmental Economics&Policies,Housing&Human Habitats,Economic Theory&Research

Reply to comment by H. Q. Feng, D. J. Wu, and J. K. Chao on “Comparison of small‐scale flux rope magnetic properties to large‐scale magnetic clouds: Evidence for reconnection across the HCS”?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94887/1/jgra20830.pd

Family Mathematics Night

The purpose of this project was to develop a family mathematics night program that would encourage parental involvement in mathematics education thus, enhancing student achievement in mathematics. Parents attending the program would: (a) become familiar with the current mathematics program used by their children; (b) learn mathematics games to play at home with their children; and (c) be introduced to various child appropriate, mathematics web sites on the Internet. Much of the material presented was recapped in a miniguide to fourth grade mathematics that was given to all the families. This guide is a tool for the parents to use at home while helping their children with mathematics. The project was reviewed by master teachers to ensure that the project goals were attained. Limitations to the project and suggestions for further study were included in Chapter Five

Application of Acoustics and Optics for the Characterization of Suspended Particulate Matter within an Estuarine Observing System

As part of this dissertation work, a long term observing station at Clay Bank on the York River in Virginia has been established and maintained since 2006, and was used to gain a better understanding of sediment processes in a muddy estuary and in muddy coastal environments in general. While data from this NSF-funded Multi-Disciplinary Benthic Exchange Dynamic (MUDBED) observing system has and will be used by other students for this general purpose, this dissertation focuses specifically on better understanding and interpretation of the data collected by key instrumentation regularly deployed at the observing station, especially the acoustic Doppler velocimeter (ADV). Chapter 1, the introduction to this dissertation, provides an overview of the setting for the MUDBED observing system, namely the York River Estuary, Virginia, and briefly discusses some of the scientific and societal issues that motivate the ongoing study of this environment. Background is provided into the history of the MUDBED observing system and into the properties and operation of the ADV and other key instruments applied in this dissertation, including the Laser In Situ Scattering Transmissometer (LISST) and two particle cameras. In the context of describing these instruments, the science papers associated with the dissertation (Chapters 2 through 6) are introduced. Chapter 2 describes use of SonTek ADVs within the real-time components of the MUDBED observing system and findings based on ADV observations through 2009. ADVs deployed at Clay Bank, and also at a more biologically-dominated down-river site, provided long-term estimates of water velocity, bottom stress, suspended sediment concentration, sediment settling velocity (ws), and bed stress under spatially and seasonally variable conditions. Bed erodibility and ws were found to be inversely correlated in both time and space, but both tended to remain more consistent in time at the biological site. at the physical site the erodibility increased and ws decreased following seasonal increases in river discharge. Chapter 3 reports on dual use of a mixing tank for calibrating SonTek ADV acoustic backscatter (ABS) and for direct Doppler measurement of w s. This study utilized the fact that, absent net vertical volume flux, the average vertical velocity registered by an ADV across a horizontal plane is equal to the sediment\u27s mean ws. A series of calibrations were run for sand sizes between 63 and 150 mum . A grid of ADV measurements revealed that the mean vertical velocity registered by the ADV was indeed consistent with each grain size\u27s ws as independently measured in a settling tube. Also, a systematic increase in the proportionality between sand concentration and ABS was observed with increasing grain size. Chapter 4 compares ABS from five 6-MHz Nortek ADVs versus five 5-MHz SonTek ADVs to examine the relative roles played by inter-vendor, intra-vendor, and sediment variability in determining their ABS response. Significant ABS offsets were found for both vendors\u27 ADVs. Before offset correction, ABS was more consistent among Nortek or SonTek units which had consecutive serial numbers. Sand calibrations indicated that the higher frequency Norteks were more susceptible to attenuation. For well-mixed silty-mud in the lab, calibration slopes for both vendors were close to the theoretical value for a constant grain-size suspension. In the field, however, a clearly different slope suggests a change in the acoustic properties of suspended particles with concentration. Chapter 5 characterizes suspended sediment at Clay Bank in the presence of both muddy flocs and pellets through use of an ADV for bulk ws, pump samples for mass concentration, and a LISST plus a high definition (non-video) particle camera for size distribution. Mass concentration, bulk ws and an abundant ---90 mm size class were found to be in phase with velocity and stress, consistent with the suspension of relatively dense, rapidly settling and resilient pellets. Volume concentration of an abundant ---300 mm class peaked well after stress and velocity began to decrease, consistent with the formation of lower density, slowly settling and fragile flocs. Chapter 6 builds on Chapter 3 by utilizing two separate ADV methods to measure ws and comparing both to observations from settling tubes. as well as direct Doppler measurement of sand, ws for mud was measured by assuming a Rouse balance between upward Reynolds flux and downward settling. Rouse-balance ADV estimates of ws were collected at Clay Bank for muddy flocs and confirmed in situ by a high-definition video settling column. Observations suggested that, in the absence of significant particle aggregation/disaggregation, (i) measurement of ws and (ii) ws itself are both relatively insensitive to the local intensity of fluid turbulence for ws up to several cm/s

A mixed methods evaluation of an individualised yoga therapy intervention for rheumatoid arthritis: Pilot study

Objectives: to explore patients’ experiences of an individualised yoga therapy intervention for rheumatoid arthritis (RA), specifically in terms of its acceptability and impact on patient-reported outcomes. Design: Ten patients took part in a 16 week yoga therapy intervention in a hospital setting, consisting of 10 one-to-one consultations with a yoga therapist followed by two group review sessions. Changes in health (EQ-5D, HADS) were assessed pre- and post-intervention and at 12-month follow-up. In-depth interviews were conducted post-intervention and analysed using thematic analysis. Results: Attendance of the 1-to-1 sessions was high (98%) and all participants reported strong commitment to their personalised home practice. There were significant improvements in measures of depression, anxiety, pain, quality of life and general health at post-intervention and 12-months (p<0.05). In interviews, all but one participant reported positive changes to their symptoms and several reported reductions in their medication and broader benefits such as improved sleep, mood and energy, enabling re-engagement with life. The personally tailored nature of the practice and perceived benefits were key motivational factors. Particular value was placed on the therapeutic function of the consultation and provision of tools to manage stress and build resilience. Conclusion: This yoga therapy intervention was positively received by patients with RA, with high levels of adherence to both the treatments and tailored home practice. The findings suggest that yoga therapy has potential as an adjunct therapy to improve RA symptoms, increase self-care behaviours and manage stress and negative affect such as anxiety. A larger multi-centre study is therefore warranted

Warranting the use of causal claims: a non-trivial case for interdisciplinarity

To what use can causal claims established in good studies be put? We give examples of studies from which inaccurate inferences were made about target policy situations. The usual diagnosis is that the studies in question lack external validity, which means that the same results do not hold in the target as in study. That’s a label that just repeats what we already knew. We offer a deeper analysis. Our analysis points to the need for interdisciplinarity and to the demand to focus not on the study – as the expression ‘external validity’ invites you to do – but on the target. The call for interdisciplinary approaches to real life problems is common since it is widely acknowledged that what happens in the real world seldom falls under the auspices of any single research domain. Our focus is on one specific real life problem: how to use causal claims from good studies to help predict whether the policies tested will work in a new situation. Our analysis of what it takes to back up these predictions points up very specific stages in the process of prediction where we are bound to get it wrong if we do not diversify our concepts, our knowledge and our methods. We isolate two reasons inferences from study to target fail. First, policy variables do not produce results on their own; they need helping factors. The distribution of helping factors is likely to be unique or local for each study, so one cannot expect external validity to be all that common. Second, researchers often give too concrete a description of the cause in the study for it to carry over to the target. Abstraction is necessary to get causes that travel. There is no sure-fire way to guard against these problems. But the unavailability of one perfect tool does not imply there are no second best contrivances. Two general pointers for Good Practice in policy advice follow from our diagnosis: focus on the concrete details in the target and use cross discipline heuristics that diversify background knowledge

Global Diffusion in a Realistic Three-Dimensional Time-Dependent Nonturbulent Fluid Flow

We introduce and study the first model of an experimentally realizable three-dimensional time-dependent nonturbulent fluid flow to display the phenomenon of global diffusion of passive-scalar particles at arbitrarily small values of the nonintegrable perturbation. This type of chaotic advection, termed {\it resonance-induced diffusion\/}, is generic for a large class of flows.Comment: 4 pages, uuencoded compressed postscript file, to appear in Phys. Rev. Lett. Also available on the WWW from http://formentor.uib.es/~julyan/, or on paper by reques