37,062 research outputs found
Primary Drivers of Software Maintenance Cost Studied Using Longitudinal Data
We examine the main drivers of software maintenance effort and cost. We use the âDistributed Cognitionâ framework to hypothesize about how âdiscovery workâ in maintenance is effected by two types of cost drivers: system attributes (size, complexity, age, etc.) and personnel attributes (number of maintainers, location dispersion, etc.). We test our hypotheses using archival data about over 5,000 maintenance projects carried out between 2009 and 2011 on 412 different operational systems in a large financial institution. We find that personnel attributes are significantly more influential than system attributes. In particular, a marginal change in personnel factors is associated with effort growing much faster than cost, indicating an escalating marginal cost of spreading maintenance work across more maintainers and site locations. We also find, counter to expectation, that two system attributes are negatively linked to maintenance effort and cost. Implications of these findings for research and practices are discussed
Toolbox of Countermeasures for Rural Two-Lane Curves, June 2012
The Federal Highway Administration (FHWA) estimates that 58 percent of roadway fatalities are lane departures, while 40 percent of fatalities are single-vehicle run-off-road (SVROR) crashes. Addressing lane-departure crashes is therefore a priority for national, state, and local roadway agencies. Horizontal curves are of particular interest because they have been correlated with increased crash occurrence.
This toolbox was developed to assist agencies address crashes at rural curves. The main objective of this toolbox is to summarize the effectiveness of various known curve countermeasures.
While education, enforcement, and policy countermeasures should also be considered, they were not included given the toolbox focuses on roadway-based countermeasures. Furthermore, the toolbox is geared toward rural two-lane curves.
The research team identified countermeasures based on their own research, through a survey of the literature, and through discussions with other professionals. Coverage of curve countermeasures in this toolbox is not necessarily comprehensive.
For each countermeasure covered, this toolbox includes the following information: description, application, effectiveness, advantages, and disadvantages
Modular space station phase B extension period executive summary
A narrative summary is presented of technical, programmatic, and planning information developed during the space station definition study extension period. The modular space station is emphasized, but tasks pertaining to shuttle sorties missions and information management advanced development are included. A series of program options considering technical, schedule, and programmatic alternatives to the baseline program are defined and evaluated
Comparative life cycle assessment of lighting systems and road pavements in an Italian twin- tube road tunnel
This work calculates and discusses the Life Cycle Assessment (LCA) of four scenarios composed of two types of road pavements and two types of lighting systems to be built in an Italian twin-tube road tunnel. A 20-year time horizon is adopted to assess the burdens of construction and maintenance of both flexible and rigid pavements and high-pressure sodium (HPS) and lightemitting diode (LED) lamps, traffic, and switching on of lamps. All considered scenarios are comparable with each other in terms of technical performances, but significantly differ regarding their environmental consequences. The geometrical and technical characteristics of the examined scenarios comply with current Italian standards for highways. In all the examined cases, LCA is carried out according to the European standard, EN 15804, and includes 19 impact categories (IC). The analysis demonstrates that the use of more reflecting surface pavement materials (i.e., concrete vs. asphalt) and more performing lighting systems (i.e., LED vs. HPS) can effectively mitigate the deleterious burdens related to road construction, maintenance, and use. For most of the examined ICs, the most environment-friendly scenario has LED lamps and concrete pavement
Ecodriving and Carbon Footprinting: Understanding How Public Education Can Reduce Greenhouse Gas Emissions and Fuel Use
Ecodriving is a collection of changes to driving behavior and vehicle maintenance designed to impact fuel consumption and greenhouse gas (GHG) emissions in existing vehicles. Because of its promise to improve fuel economy within the existing fleet, ecodriving has gained increased attention in North America. One strategy to improve ecodriving is through public education with information on how to ecodrive. This report provides a review and study of ecodriving from several angles. The report offers a literature review of previous work and programs in ecodriving across the world. In addition, researchers completed interviews with experts in the field of public relations and public message campaigns to ascertain best practices for public campaigns. Further, the study also completed a set of focus groups evaluating consumer response to a series of websites that displayed ecodriving information. Finally, researchers conducted a set of surveys, including a controlled stated-response study conducted with approximately 100 University of California, Berkeley faculty, staff, and students, assessing the effectiveness of static ecodriving web-based information as well as an intercept clipboard survey in the San Francisco Bay Area. The stated-response study consisted of a comparison of the experimental and control groups. It found that exposure to ecodriving information influenced peopleâs driving behavior and some maintenance practices. The experimental groupâs distributional shift was statistically significant, particularly for key practices including: lower highway cruising speed, driving behavior adjustment, and proper tire inflation. Within the experimental group (N = 51), fewer respondents significantly changed their maintenance practices (16%) than the majority that altered some driving practices (71%). This suggests intentionally altering driving behavior is easier than planning better maintenance practices. While it was evident that not everyone modifies their behavior as a result of reviewing the ecodriving website, even small shifts in behavior due to inexpensive information dissemination could be deemed cost effective in reducing fuel consumption and emissions
Advanced Manned Launch System (AMLS) study
To assure national leadership in space operations and exploration in the future, NASA must be able to provide cost effective and operationally efficient space transportation. Several NASA studies and the joint NASA/DoD Space Transportation Architecture Studies (STAS) have shown the need for a multi-vehicle space transportation system with designs driven by enhanced operations and low costs. NASA is currently studying an advanced manned launch system (AMLS) approach to transport crew and cargo to the Space Station Freedom. Several single and multiple stage systems from air-breathing to all-rocket concepts are being examined in a series of studies potential replacements for the Space Shuttle launch system in the 2000-2010 time frame. Rockwell International Corporation, under contract to the NASA Langley Research Center, has analyzed a two-stage all-rocket concept to determine whether this class of vehicles is appropriate for the AMLS function. The results of the pre-phase A study are discussed
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A Survey on Cooperative Longitudinal Motion Control of Multiple Connected and Automated Vehicles
Report on relationship management and culture change
Brisbane Water (BW), a commercialised business arm of Brisbane City Council (BCC) entered into an
alliance with a number of organisations from the private sector in order to design, construct, commission
and undertake upgrades to three existing wastewater treatment plants located at Sandgate, Oxley Creek,
and Wacol in Brisbane. The alliance project is called the Brisbane Water Environmental Alliance (BWEA).
This report details the efforts of a team of researchers from the School of Management at Queensland
University of Technology to investigate this alliance. This is the second report on this project, and is
called Stage 2 of the research. At the time that Stage 2 of the research project was conducted, the BWEA
project was nearing completion with a further 8 months remaining before project completion.
The aim of this report is to explore individualsâ perceptions of the effectiveness and functioning of the
BWEA project in the latter stages of the project. The second aim of this report is to analyse the
longitudinal findings of this research project by integrating the findings from Stage 1 and Stage 2 of the
project. This long-term analysis of the functioning and effectiveness of the alliance is important because
at the current time, researchers have little knowledge of the group developmental processes that occur in
large-scale alliances over time.
Stage 2 of this research project has a number of aims including assessing performance of the BWEA
project from the point of view of a range of stakeholders including the alliance board and alliance
management team, alliance staff, and key stakeholders from the client organisation (Brisbane Water).
Data were collected using semi-structured interviews with 18 individuals including two board members,
one external facilitator, and four staff members from the client organisation. Analysis involved coding the
interview transcripts in terms of the major issues that were reported by interviewees
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