170 research outputs found
Reforming Project Management: The Role of Planning, Execution and Controlling
In this paper, we focus on the need for reforming the role of plans, execution (or action) and control in project management. We argue that the present style of project management, as described in the Guide to the Project Management Body of Knowledge (PMBOK Guide) of PMI, is based on two underlying theories in this regard: management-as-planning (for planning and execution) and the thermostat model (for control). Unfortunately, both theories can be shown to be heroically simplistic and insufficient from the point of view of project management reality. In consequence, the practice of project management suffers from three shortcomings. The vague interface between planning and execution is the cause for two of them. First, the role of planning is not realistically defined, and short term planning (that is critical from the point of view of execution) is customarily poorly carried out or simply neglected. Secondly, there is no systematic way of managing execution, i.e. taking into account the actual conditions of the real world as higher level plans are translated into short term plans and then into action. Thirdly, control is too narrowly seen as measuring and taking corrective action, rather than as a process of learning. These arguments are justified by empirical data and theoretical discussion
Understanding Construction Supply Chains: An Alternative Interpretation
Much research work has assessed that construction is ineffective and many problems can be observed. Analysis of these problems has shown that a major part of them are supply chain problems, originating at the interfaces of different parties or functions. There have been several kinds of initiatives aiming at improvement and renewal of construction supply chains, but only few have a track record of consequent and significant successes. Here construction supply chains are approached from an alternative theoretical viewpoint, namely that of the language/action perspective. In this approach, organizations are seen as networks of commitments. Two avenues have been pinpointed for practical application of this approach. First, the process of requesting, creating and monitoring commitments can be facilitated by heuristic models and computer systems, when suitably designed. Secondly, people can learn to communicate for action by developing new sensibility towards the ways their language acts participate in networks of human commitments, and improving their skills in understanding requests, and making commitments. By closer study, existing empirical observations support the idea that a large share of construction supply chain problems are caused by poor articulation and activation of commitments. But would this new approach also facilitate the implementation of a new supply chain management that has proved to be so difficult in practice? In this regard, two initiatives are reviewed. The Dutch initiative to create a framework for communication in large civil engineering projects is first presented and initial experiences from its implementation are discussed. Then, Last Planner implementations are analyzed. By drawing on the concept of small wins, it is concluded that these implementations act as a stimulus for wider changes towards an environment of firm commitments and high trust. The paper ends with a review on research tasks ahead
If CPM is so bad, why have we been using it so long?
Why has the Critical Path Method (CPM) been used so widely for so long given its inability to produce predictable outcomes? For shedding light on this paradox, the formative period of the CPM is analysed from two main angles. First, how was the CPM embedded into the construction management practice? Second, what was the methodological underpinning of the development of the CPM? These questions are researched through a literature review.
In terms of embeddedness into practice, it turns out that the CPM morphed from being a way of production control, into a method for contract control. In consequence, the promotion of the CPM by owners has been crucial for pushing this method to be the mainstream approach to scheduling and production control.
Regarding methodological underpinning, it turns out that the CPM was developed as a way of optimization, as part of the quantitative methods movement. This movement was largely based on the axiomatic approach to research. In good alignment with that approach, there was no attempt to empirically test quantitative models and their outcomes. In this context, the unrealistic assumptions and conceptualizations in CPM did not surface in forty years.
These results are argued to be helpful in critical discussions on the role and merits of CPM and on the methodologies to be used in construction management research
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Emotional Biosensing: Exploring Critical Alternatives
Emotional biosensing is rising in daily life: Data and categories claim to know how people feel and suggest what they should do about it, while CSCW explores new biosensing possibilities. Prevalent approaches to emotional biosensing are too limited, focusing on the individual, optimization, and normative categorization. Conceptual shifts can help explore alternatives: toward materiality, from representation toward performativity, inter-action to intra-action, shifting biopolitics, and shifting affect/desire. We contribute (1) synthesizing wide-ranging conceptual lenses, providing analysis connecting them to emotional biosensing design, (2) analyzing selected design exemplars to apply these lenses to design research, and (3) offering our own recommendations for designers and design researchers. In particular we suggest humility in knowledge claims with emotional biosensing, prioritizing care and affirmation over self- improvement, and exploring alternative desires. We call for critically questioning and generatively re- imagining the role of data in configuring sensing, feeling, âthe good life,â and everyday experience
Discovery of Non-radial pulsations in PQ Andromedae
We have detected pulsations in time-series photometry of the WZ Sge dwarf
nova PQ And. The strongest peak in the power spectrum occurs at a period of
10.5 minutes. Similar periods have been observed in other WZ Sge systems and
are attributed to ZZ Ceti type non-radial pulsations. There is no indication in
the photometry of an approximately 1.7 hour orbital period as reported in
previous spectroscopic observations.Comment: 7 pages, 5 figure
Operational Experience with Long Duration Wildfire Mapping: UAS Missions Over the Western United States
The National Aeronautics and Space Administration, United States Forest Service, and National Interagency Fire Center have developed a partnership to develop and demonstrate technology to improve airborne wildfire imaging and data dissemination. In the summer of 2007, a multi-spectral infrared scanner was integrated into NASA's Ikhana Unmanned Aircraft System (UAS) (a General Atomics Predator-B) and launched on four long duration wildfire mapping demonstration missions covering eight western states. Extensive safety analysis, contingency planning, and mission coordination were key to securing an FAA certificate of authorization (COA) to operate in the national airspace. Infrared images were autonomously geo-rectified, transmitted to the ground station by satellite communications, and networked to fire incident commanders within 15 minutes of acquisition. Close coordination with air traffic control ensured a safe operation, and allowed real-time redirection around inclement weather and other minor changes to the flight plan. All objectives of the mission demonstrations were achieved. In late October, wind-driven wildfires erupted in five southern California counties. State and national emergency operations agencies requested Ikhana to help assess and manage the wildfires. Four additional missions were launched over a 5-day period, with near realtime images delivered to multiple emergency operations centers and fire incident commands managing 10 fires
Signatures of granular microstructure in dense shear flows
Granular materials react to shear stresses differently than do ordinary
fluids. Rather than deforming uniformly, materials such as dry sand or
cohesionless powders develop shear bands: narrow zones containing large
relative particle motion leaving adjacent regions essentially rigid[1,2,3,4,5].
Since shear bands mark areas of flow, material failure and energy dissipation,
they play a crucial role for many industrial, civil engineering and geophysical
processes[6]. They also appear in related contexts, such as in lubricating
fluids confined to ultra-thin molecular layers[7]. Detailed information on
motion within a shear band in a three-dimensional geometry, including the
degree of particle rotation and inter-particle slip, is lacking. Similarly,
only little is known about how properties of the individual grains - their
microstructure - affect movement in densely packed material[5]. Combining
magnetic resonance imaging, x-ray tomography, and high-speed video particle
tracking, we obtain the local steady-state particle velocity, rotation and
packing density for shear flow in a three-dimensional Couette geometry. We find
that key characteristics of the granular microstructure determine the shape of
the velocity profile.Comment: 5 pages, incl. 4 figure
The Great Observatories All-Sky LIRG Survey: Comparison of Ultraviolet and Far-Infrared Properties
The Great Observatories All-sky LIRG Survey (GOALS) consists of a complete
sample of 202 Luminous Infrared Galaxies (LIRGs) selected from the IRAS Revised
Bright Galaxy Sample (RBGS). The galaxies span the full range of interaction
stages, from isolated galaxies to interacting pairs to late stage mergers. We
present a comparison of the UV and infrared properties of 135 galaxies in GOALS
observed by GALEX and Spitzer. For interacting galaxies with separations
greater than the resolution of GALEX and Spitzer (2-6"), we assess the UV and
IR properties of each galaxy individually. The contribution of the FUV to the
measured SFR ranges from 0.2% to 17.9%, with a median of 2.8% and a mean of 4.0
+/- 0.4%. The specific star formation rate of the GOALS sample is extremely
high, with a median value (3.9*10^{-10} yr^{-1}) that is comparable to the
highest specific star formation rates seen in the Spitzer Infrared Nearby
Galaxies Survey sample. We examine the position of each galaxy on the IR
excess-UV slope (IRX-beta) diagram as a function of galaxy properties,
including IR luminosity and interaction stage. The LIRGs on average have
greater IR excesses than would be expected based on their UV colors if they
obeyed the same relations as starbursts with L_IR < 10^{11}L_0 or normal
late-type galaxies. The ratio of L_IR to the value one would estimate from the
IRXg-beta relation published for lower luminosity starburst galaxies ranges
from 0.2 to 68, with a median value of 2.7. A minimum of 19% of the total IR
luminosity in the RBGS is produced in LIRGs and ULIRGs with red UV colors (beta
> 0). Among resolved interacting systems, 32% contain one galaxy which
dominates the IR emission while the companion dominates the UV emission. Only
21% of the resolved systems contain a single galaxy which dominates both
wavelengths.Comment: 37 pages, 10 figures, accepted for publication in Ap
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