Design ethnography in information systems

Until recently, most ethnographic research in information systems has been based on the traditional anthropological model of ethnography. In this traditional model of ethnography, one of the most important data‐gathering techniques is participant observation. The ethnographer observes and participates but does not actively seek to change the situation. In recent years, however, a new type of ethnographic research has emerged – one that can be called design ethnography. Design ethnography is where the researcher goes beyond observation and actively engages with people in the field. Our view is that design ethnography has much potential for research in information systems. It is a new form of engaged scholarship that bridges the gap between ethnographic research and design science research.     

An Exploratory Study of How Developers Seek, Relate, and Collect Relevant Information during Software Maintenance Tasks

Much of software developers' time is spent understanding unfamiliar code. To better understand how developers gain this understanding and how software development environments might be involved, a study was performed in which developers were given an unfamiliar program and asked to work on two debugging tasks and three enhancement tasks for 70 minutes. The study found that developers interleaved three activities. They began by searching for relevant code both manually and using search tools; however, they based their searches on limited and misrepresentative cues in the code, environment, and executing program, often leading to failed searches. When developers found relevant code, they followed its incoming and outgoing dependencies, often returning to it and navigating its other dependencies; while doing so, however, Eclipse's navigational tools caused significant overhead. Developers collected code and other information that they believed would be necessary to edit, duplicate, or otherwise refer to later by encoding it in the interactive state of Eclipse's package explorer, file tabs, and scroll bars. However, developers lost track of relevant code as these interfaces were used for other tasks, and developers were forced to find it again. These issues caused developers to spend, on average, 35 percent of their time performing the mechanics of navigation within and between source files. These observations suggest a new model of program understanding grounded in theories of information foraging and suggest ideas for tools that help developers seek, relate, and collect information in a more effective and explicit manner     

A mathematical model for nanoparticle melting with size-dependent latent heat and melt temperature

In this paper, we study the melting of a spherical nanoparticle. The model differs from previous ones in that a number of features have been incorporated to match experimental observations. These include the size dependence of the latent heat and a cooling condition at the boundary (as opposed to the fixed temperature condition used in previous studies). Melt temperature variation and density change are also included. The density variation drives the flow of the outer fluid layer. The latent heat variation is modelled by a new relation, which matches experimental data better than previous models. A novel form of Stefan condition is used to determine the position of the melt front. This condition takes into account the latent heat variation, the energy required to create new surface and the kinetic energy of the displaced fluid layer. Results show that melting times can be significantly faster than predicted by previous theoretical models; for smaller particles, this can be around a factor 3. This is primarily due to the latent heat variation. The previously used fixed temperature boundary condition had two opposing effects on melt times: the implied infinite heat transfer led to faster melting but also artificially magnified the effect of kinetic energy, which slowed down the process. We conclude that any future models of nanoparticle melting must be based on the new Stefan condition and account for latent heat variation.     

Vicarious calibration of the moderate-resolution imaging spectroradiometer airborne simulator thermal-infrared channels

We made an experimental vicarious calibration of the Moderate Resolution Imaging Spectroradiometer (MODIS) Airborne Simulator (MAS) thermal infrared (TIR) channel data acquired in the field campaign near Mono Lake, Calif. on 10 March 1998 to demonstrate the advantage of using high-elevation sites in dry atmospheric conditions for vicarious calibration. With three lake-surface sites and one snow-field site, we estimated the MAS noise-equivalent temperature difference as 0.7-1.0 degrees C for bands 30-32 in the 3.68-4.13-microm region and 0.1-0.5 degrees C for bands 42, 45, 46, and 48 in the 8-13.5-microm region. This study shows that the MAS calibration error is within +/-0.4 degrees C in the split-window channels (at 11 and 12 microm) and larger in other TIR channels based on the MAS data over Mono Lake and in situ measurement data over the snow-field site.     

Effect of backpack fit on lung function

Carrying loads close to the trunk with a backpack causes a restrictive type of change in lung function in which Forced Vital Capacity (FVC) and Forced Expiratory Volume in 1 s (FEV1) are reduced without a corresponding decrement in the FEV1.FVC( - 1) %. It is not known whether this is due to the weight of the load acting on the chest or to the tightness of fit of the shoulder and chest straps and waist belt of the pack harness. This study examined FVC, FEV1, FEV1.FVC( - 1) %, peak expiratory flow (PEF), forced expiratory flow between 0.2 and 1.2 s (FEF0.2 - 1.2) after the start of expiration and between 25 and 75% of each FVC (FEF25 - 75%) in 12 healthy males wearing a 15 kg backpack in which the shoulder and chest straps and hip belt were loosened by 3 cm from a 'comfort fit' to achieve a 'loose pack' fit (LPF) and tightened by 3 cm from CF to achieve a 'tight pack' fit (TPF). In comparison with the control condition of no pack, a loose pack fit significantly reduced FVC (by 3.6%, p < 0.01), FEV1 (by 4.3%, p < 0.01) and FEF25 - 75% (by 8.4%, p < 0.01). A tight pack fit significantly reduced FVC (by 8.1%, p < 0.01) and FEV1 (by 9.1%, p < 0.001). It also significantly reduced FEF0.2 - 1.2 (by 7.3%, p < 0.05) and FEF25 - 75% (by 21%, p < 0.01). In comparison with a loose pack fit, the tight pack fit was associated with a significantly lower FVC (by 4.6%, p < 0.01), FEV1 (by 5.0%, p < 0.01), FEF25 - 75% (by 13.8%, p < 0.01) and a fall in FEF0.2 - 1.2 (by 5.5%). The latter was approaching significance (p = 0.077). There were no significant changes in FEV1.FVC( - 1)% and PEF. It is concluded that tightening the fit of a backpack significantly affects lung function in a manner that is typical of a restrictive change in lung function and is very similar in pattern to that of wearing a loosely fitted loaded backpack. The effect of tightness of fit is additional to that due to the weight of the load alone and may also reduce expiratory flow at low lung volumes.     

Object–person discrimination and communication at 3 and 10 months.

J. Contole and R. Over's (1979, 1981) procedure for studying infant discrimination using a signal detection analysis of observers' ratings of infant behavior was used to test claims by E. Tronick et al (see record 1980-07280-001) that 3-mo-olds distinguish people from objects and nonverbally communicate with familiar caregivers. 12 observers—parents and undergraduates—judged from videotaped samples of 3- and 10-mo-old infants' behavior if the infants were alone or otherwise, if they were with something that was active or passive, and if they were greeting or withdrawing. Observers could only judge whether the infants were with their mother or an object for the 10-mo-olds. The greeting–withdrawal results seem to indicate that 3-mo-olds do communicate with their caregivers; however, observers were also able to judge greeting–withdrawal when the infants were with an object. There were no sensitivity differences between the 2 observer groups, although the parents were biased to expect the infants to be with mother and to be greeting. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estimates of uncertainty for measured spectra in the SERI spectral solar radiation data base

The Solar Energy Research Institute's (SERI) Solar Radiation Resource Assessment Project collected spectral solar irradiance data and coincident insolation and meterological data from October 1986 to May 1988. This article describes the methods used to derive the wavelength-dependent measurement uncertainty for each spectral scan (i.e., spectra). We list the sources of uncertainty in calibration and field measurements, and present summaries of the magnitudes for each. Finally, we show derived uncertainty envelopes, representative of the 21 combinations of instruments, measurement modes, and measurement periods used during the project. Our results indicate uncertainly of greater than ±20% for the ultraviolet (300 to 400 nm), +5% to − 13% in the visible (400 to 900 nm), and + 8% to − 15% in the near infrared (900 to 1100 nm). Complete details of the analysis summarized here are available in separate SERI technical reports detailing the data base, its structure; and the uncertainty analysis.     

Acute cardio-respiratory changes induced by hyperpnoea using a respiratory muscle trainer

The aim of this study was to examine the cardio-respiratory effects of voluntary hyperpnoea using a respiratory muscle trainer (RMT) with three different sized rebreathing bags. In particular, the effects of hyperpnoea on inspired and end-tidal gas concentrations were determined. Seven adult males completed three 30 min bouts of hyperpnoea using optimal, oversized and undersized rebreathing bags. Inspired (F(I)) and expired end-tidal (F(ET)) O2 and CO2 concentrations, arterial O2 saturation (S(AO2)) and heart rate were measured during hyperpnoea. Before and after a bout of hyperpnoea, pulmonary function and blood pressure (BP) were assessed. Data were analysed using a two-way repeated-measures ANOVA, with p < 0.05 considered significant. Three subjects experienced discomfort during hyperpnoea and stopped after 20 min. During hyperpnoea, the F(ETCO2) was maintained at 4.6 +/- 0.7% irrespective of bag size. The increase in F(ICO2) over time reached 0.5 +/- 0.5% at 20 min. The F(IO2) fell to 19.4 +/- 0.8% at 20 min, and S(AO2) decreased to 97%. Heart rate and systolic BP increased slightly, but independently of rebreathing bag volume. No changes in pulmonary function or diastolic BP were found. It is concluded that the RMT maintained a constant F(ETCO2) at the expense of a mild hypoxia. The acute effects of hyperpnoea on the cardio-respiratory system are generally mild, but not always tolerable for 30 min.     

Lessons learned from programmers' experiences with one‐way constraints

One‐way constraints have been incorporated in many graphical user interface toolkits because they are simple to learn, easy to write, and can express many types of useful graphical relationships. This paper is an evaluative paper that examines users' experience with one‐way constraints in two user interface development toolkits, Garnet and Amulet, over a 15‐year time span. The lessons gained from this examination can help guide the design of future constraint systems. The most important lessons are that (1) constraints should be allowed to contain arbitrary code that is written in the underlying toolkit language and does not require any annotations, such as parameter declarations, (2) constraints are difficult to debug and better debugging tools are needed, and (3) programmers will readily use one‐way constraints to specify the graphical layout of an application, but must be carefully and time‐consumingly trained to use them for other purposes. Copyright © 2005 John Wiley & Sons, Ltd.     

The Effect of Target Vector Selection on the Invariance of Classifier Performance Measures

In this paper, the multiclass supervised training problem is considered when a discrete set of classes is assumed. Upon generating affine models for finite data sets, we have observed the invariance of certain measures of performance after a trained classifier has been presented with test data of unknown classification. Specifically, after constructing mappings between training vectors and their desired targets, the class membership and ranking of test data has been found to remain either invariant or close to invariant under a transformation of the set of target vectors. Therefore, we derive conditions explaining how this type of invariance can arise when the multiclass problem is phrased in the context of linear networks. A bioinformatics example is then presented in order to demonstrate various principles outlined in this work.