802 research outputs found
The Narrow-Line Region in the Seyfert 2 Galaxy NGC 3393
The narrow-line region (NLR) of the Seyfert 2 galaxy NGC 3393 is dominated by a symmetric structure which appears as S-shaped arms in Hubble Space Telescope (HST) images. These arms, which occupy the central few arcseconds of the nucleus, border a linear, triple-lobed radio source. We use HST imaging and spectra, ground-based optical images, long-slit spectra, Fabry-Perot imaging spectroscopy, and VLA radio data to perform a detailed investigation of the kinematics and ionization of the line-emitting gas in NGC 3393 and of its relationship with the relativistic gas responsible for the radio emission. The excitation map [O III] λ5007/(Hα + [N II] λλ6548, 6584) shows a biconical structure, consistent with the anisotropic nuclear ionizing radiation expected in the unified scheme. Extrapolation to ionizing frequencies of our upper limit to the 2100 Å flux of the nuclear source provides a factor ≥3 × 104 too few ionizing photons to account for the recombination line emission, which also suggests that the nuclear ionizing source radiates anisotropically. However, the kinetic energy of the outflow is sufficient to power the line emission via photoionizing shocks, and a tentative detection of extended UV emission is consistent with this model. Furthermore, the broad component of the emission lines has a similar orientation and spatial extent as the triple radio source. Nevertheless, other tests are inconsistent with the photoionizing shock model—there is no correlation between local velocity dispersion, surface brightness, and excitation, and the gaseous abundances of [Ca II], Al II], and Mg II are much lower than expected if these species have been liberated into the gas phase through grain destruction by shocks. We conclude that the radio lobes appear to have created denser regions of gas on their leading edges, thus forming the S-shaped arms, but that the ionization is most likely due to photoionization by an obscured central source
THE INTERACTIONS OF GENERALS AND COMMANDERS, AND THEIR EFFECTS ON OPERATIONS
This study examines an overarching research question: to what extent do
military leaders’ personalities and command relations affect strategy and
operations? The method used for this study is a single-case qualitative case study
applied to an historical exemplar of the relationship between Generals Eisenhower and
Spaatz during the Combined Bomber Offensive (CBO) for the purpose of initial
development of theory for General Officer (GO) professional interpersonal conduct. The
reason for choosing this particular case is that this relationship occurred amidst one of the
most turbulent strategic times for GOs and fostered a great deal of cooperation amongst a
large group of GOs. The case study hypotheses were disproved as strategic decisions
were made from an analytic standpoint and not borne out of personality conflicts or blind
spots due to personal schema. It is concluded that the conduct of GOs can radically alter
strategy and it is of utmost importance that officers conduct themselves in a manner
divorced from any personal conflicts for the best allocation of combat forces
A Proposal to Federally Legalize Recreational Cannabis
This policy proposal examines the issue of the disparity between Federal and State positions regarding cannabis legalization with regards to State cross-border criminal activity and the preeminence of Federal law. The proposal is based on examination of the history of Federal cannabis prohibition policies, State legalization policies, cannabis’ part in drug law enforcement, and the growing legal cannabis industry. No Federal court has yet to tackle the disparity between Federal prohibition of cannabis and the 33 States that have legalized cannabis to some degree (either medicinally or recreationally). This demonstrates a reluctance to truly continue Federal prohibition out of nothing more than decades of flawed drug enforcement policies. Therefore, it was recommended that, in light of the U.S. House of Representatives passing the MORE Act of 2019, the Federal government should legalize cannabis products recreationally in order to more effectively establish a legal cannabis industry with regulations similar to the alcohol and tobacco industries currently
A more representative chamber: representation and the House of Lords
Since 1997 there has been substantive reform of the House of Lords in an effort to make the chamber ‘more democratic and more representative’. Whilst the Labour government failed to press ahead with any of the proposed plans for further reform following the removal of the bulk of the hereditary peers in 1999, it remained committed to the notion that such reform must make the second chamber ‘more representative’. The coalition government's programme advocates a long-term aspiration for a House wholly or mainly elected on the basis of proportional representation, and a short-term approach based on additional appointments to ensure a balance of the parties. What is clear in all of these proposals for reform is a desire for the House of Lords to become more representative than it is at present. However, what is less clear is what is meant by ‘representative’ – who the House of Lords is supposed to represent, and what form representation will take. Moreover, in proposing to make the chamber more representative, either through appointment or election, little attention has been paid to how the current House of Lords provides representation. This article examines these questions in the context of Pitkin's classic conceptions of representation and peers' attitudes towards their own representative rol
BPM-driven construction client requirements change management
Changing client requirements is one of the principal factors that contribute to delays and budget overruns of
construction projects which as a result causes claims, disputes and client dissatisfaction. Change management
ensures that such changes are handled through a properly coordinated and controlled process and retained
throughout the project life cycle. This paper presents an empirical study that investigated the potential for an
automated process of managing changes to clients’ requirements in construction projects. An initial focus
group meeting was set up as a preliminary study which was followed by two case studies. Participant observation
was used to conduct the case studies during which technical documents were also reviewed. The results
show that current requirements change management process lacks efficiency. The paper concludes that business
process management (BPM) approach could be a solution to better manage the requirements change process
Lifecycle approach to requirements information management in construction projects: state-of-the-art and future trends
Changes in client requirements are most frequent in construction and are known to
contribute to budget over-runs and late delivery of projects. Such changes need to be
managed adequately to enhance visibility, traceability and linked to the original
requirements and communication with all stakeholders throughout the lifecycle of a
facility. Traditionally, requirements management has principally been focused at the
early stages of the construction process where elicited client requirements information
is used as the basis for design and does not extend to the later phases. A life cycle
approach is important because client requirements often change dramatically over a
facility’s life. This evolution needs to be understood, for example, particularly if the
facility is to be refurbished or adapted for uses other than those for which it was
originally designed. This paper presents an empirical study to highlight the current
state of managing clients’ requirements and to propose the need for a lifecycle
approach to requirements information management in construction projects. An
ethnographic study was conducted to examine the requirements management process
based on participatory observations of construction project meetings and interviews
with project managers. The study also details the state-of-the-art of requirements
management by presenting a qualitative review of literature on this topic. This review
includes industries other than construction.
The paper concludes that currently, with no lifecycle insight, very few informal
schemes detail the management of requirements beyond the design process into the
later stages of the project. It proposes that the management of requirements should
extend beyond elicitation and documentation and requires an approach that will
enable changeability and impact analysis, accessibility, traceability and
communication to all stakeholders
An integrated requirements management system for construction projects
Within the AEC/FM Industry, the current paper-based system used to manage client requirements information and the change request process lacks efficiency and effectiveness. Traditionally, requirements management has principally been focused at the early stages of a construction project where elicited client requirements information is used as the basis for design and does not extend to later phases. Links between corresponding requirements at different phases do not exist which makes traceability difficult. There are no methods to keep track of client requirements and the changes in a satisfactory way that take a whole lifecycle approach. Construction organisations, like other engineering related businesses, are turning to computer systems (to replace current manual and paper intensive processes) in their quest for practical ways to facilitate requirements information management. This paper presents a prototype system for client requirements information management taking a whole lifecycle approach. It comprises of integrated components made up of a repository and change management system (CMS). The prototype was developed following case studies of construction projects and interviews with construction experts in order to fully understand the need for such a system. The applicability and effectiveness of the prototype will be validated using a focus group made up of various construction stakeholders and academic practitioners
Development of an innovative framework for clients' requirements information management in construction projects
Properly managing client requirements information can contribute to high construction
productivity and improve the quality of built facilities. This paper presents an innovative
framework which defines a life-cycle approach to managing client requirements information.
The Enterprise Requirements Information Management Framework (eRIM) introduces an
approach to managing client requirements throughout a project lifecycle. It defines an
information-centric and process-oriented approach to requirements management and
describes how Information Technology (IT) / Information Systems (IS) can serve as support
tool. It supports life-cycle requirements information availability, facilitates coordination,
enables visibility, traceability and dependency checking which is crucial for analysing the
impact of proposed changes in requirements. The paper includes findings from three case
studies of construction projects through observations of meetings and interviews with
selected construction practitioners. The results indicate that implementation and
incorporation of the framework in construction projects could contribute towards improved
performance and more efficient and effective client requirements management
An empirical study of the complexity of requirements management in construction projects
Purpose
– The purpose of this paper is to investigate in-depth the current approach of managing client requirements in construction and to highlight the significant factors, which contribute to the complexity of managing the requirements in order to define a better approach.
Design/methodology/approach
– A case study of a leading international global built asset and engineering consultancy organization was conducted over two years. The case study was conducted principally using semi-participant observations supplemented with other qualitative data collection methods (i.e. interviews, questionnaires and document analysis). Thematic analysis was used to analyze the data.
Findings
– The results highlight major factors associated with the complexity of managing client requirements information, which include: mechanisms for documentation, storage and access, distribution of requirements information between stakeholders and across lifecycle phases of a project, traceability management and the provision of effective change management incorporating dependency checking and impact analysis.
Research limitations/implications
– The main limitation of the research is the use of an in-depth study of a single organization, which applied the same project management method across all the projects they managed. Further work is planned to develop the proposed framework fully, and develop a software platform to operationalize and evaluate its industrial applicability with construction projects.
Practical implications
– The implications of this research is that a better approach to managing requirements information is needed, which will facilitate the design, construction and operations of buildings within budget and time. An integrated framework and an associated tool are suggested to implement the approach.
Originality/value
– This study identifies major research gaps and problems in the architecture, engineering, construction and facilities management industry; proposes and presents Electronic Requirements Information Management framework to facilitate lifecycle management of the requirements
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