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The Optimal MR Acquisition Strategy for Exponential Decay Constants Estimation★

Fleysher, Roman; Fleysher, Lazar; Gonen, Oded
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.04%
Estimating the relaxation constant of an exponentially decaying signal from experimental MR data is fundamental in diffusion tensor imaging, fractional anisotropy mapping, measurements of transverse relaxation rates and contrast agent uptake. The precision of such measurements depends on the choice of acquisition parameters made at the design stage of the experiments. In this report, χ2 fitting of multi-point data is used to demonstrate that the most efficient acquisition strategy is a two-point scheme. We also conjecture that the smallest cofficient of variation of the decay constant achievable in any N-point experiment is 3.6 times larger than that in the image intensity obtained by averaging N acquisitions with minimal exponential weighting.

Foliar water uptake: a common water acquisition strategy for plants of the redwood forest

Limm, Emily Burns; Simonin, Kevin A.; Bothman, Aron G.; Dawson, Todd E.
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
45.96%
Evaluations of plant water use in ecosystems around the world reveal a shared capacity by many different species to absorb rain, dew, or fog water directly into their leaves or plant crowns. This mode of water uptake provides an important water subsidy that relieves foliar water stress. Our study provides the first comparative evaluation of foliar uptake capacity among the dominant plant taxa from the coast redwood ecosystem of California where crown-wetting events by summertime fog frequently occur during an otherwise drought-prone season. Previous research demonstrated that the dominant overstory tree species, Sequoia sempervirens, takes up fog water by both its roots (via drip from the crown to the soil) and directly through its leaf surfaces. The present study adds to these early findings and shows that 80% of the dominant species from the redwood forest exhibit this foliar uptake water acquisition strategy. The plants studied include canopy trees, understory ferns, and shrubs. Our results also show that foliar uptake provides direct hydration to leaves, increasing leaf water content by 2–11%. In addition, 60% of redwood forest species investigated demonstrate nocturnal stomatal conductance to water vapor. Such findings indicate that even species unable to absorb water directly into their foliage may still receive indirect benefits from nocturnal leaf wetting through suppressed transpiration. For these species...

Implementing Coordinative Acquisition as a Viable Streamlined Acquisition Process in the Department of Defense (DoD): Will Contractors Participate

Charles B. Froemke; Jerry M. Tanner
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Relevância na Pesquisa
46.11%
Sponsored Report (for Acquisition Research Program); The purpose of this MBA Project is to discuss the use of the coordinative acquisition tool, which supports Defense Acquisition Performance Assessment (DAPA) recommendations calling for more streamlined acquisition architecture. Specifically, we conduct an analysis of the coordinative acquisition strategy as presented by Dr. Joseph P. Avery in his January 2006 presentation entitled, 'Coordinative Acquisition Strategies; Hyperswift Response to the Warfighter' as an acquisition tool used outside of the Federal Acquisition Regulation (FAR). We compare this method to DoD Directive 5000.1, DAPA, and other acquisition policies calling for acquisition cycle-time reduction and for a more simplified acquisition architecture. We also conduct a case study on the Rapid Identification Friend or Foe (RIFF) test kit prototype and develop lessons learned as it relates to DoD-wide implementation of coordinative acquisition as a viable streamlined acquisition tool for rapid acquisition of immature technologies necessary for warfighter support. We also discuss interviews with Government and industry representatives at all levels in order to better explore legal and ethical considerations of coordinative acquisition. Feedback from these interviews provides useful insight into industry's actual willingness to accept this form of acquisition for future projects within the DoD.

Analysis of Modular Open Systems Approach (MOSA) Implementation in Navy Acquisition Programs

Rendon, Rene G.
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Tipo: Relatório
Relevância na Pesquisa
46.04%
Proceedings Paper (for Acquisition Research Program); This research continues the exploration of the use of the modular open systems approach (MOSA) as a method for implementing an evolutionary acquisition strategy in Department of Defense (DoD) programs. The background on the initial DoD and Navy policy on using a MOSA approach in defense acquisition is presented, followed by a review of the initial research findings. A discussion is then provided on the Navy's method for assessing its implementation of a MOSA approach in its acquisition programs. This discussion will focus on the use of the Naval Enterprise Open Architecture Assessment Tool (OAAT). The primary purpose of this continuing research is to provide an analysis of the results of the OAAT assessment of Navy acquisition programs.

Acquisition Management for Systems-of-systems: Exploratory Model Development and Experimentation

Daniel DeLaurentis; Muharrem Mane
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Tipo: Relatório
Relevância na Pesquisa
46.05%
Proceedings Paper (for Acquisition Research Program); In recent years, the Department of Defense (DoD) has placed a growing emphasis on the pursuit of agile capabilities via net-enabled operations. In this setting, systems are increasingly required to interoperate along several dimensions. Yet, the manner in which components of these 'system-of-systems' (SoS) are acquired (designed, developed, tested and fielded) has not kept pace with the shifts in operational doctrine. Acquisition programs have struggled with complexities in both program management and engineering design. We have developed a conceptual model for pre-acquisition and acquisition strategy in an SoS environment and have implemented it in an exploratory, dynamic model. The model allows acquisition professionals to develop intuition for procuring and deploying system-of-systems by providing a venue for experimentation through which they can develop insights that will underpin successful acquisition of SoS-oriented defense capabilities. This paper presents example studies that demonstrate the capabilities of the dynamic model and highlight the importance of project characteristics. Specifically, we investigate the impact of SoS attributes'requirement interdependency, project risk...

Acquisition Management for System-of-Systems: Requirement Evolution and Acquisition Strategy Planning

Seung Yeob Han; Zhemei Fang; Daniel DeLaurentis
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Tipo: Relatório
Relevância na Pesquisa
56.14%
Proceedings Paper (for Acquisition Research Program); The complex interdependencies between systems organized for a system-of-systems (SoS) capability pose a challenge to effective acquisition management of SoS assets. In general, methodologies to assess risk that cascades through interdependencies are critical to effectively analyzing alternatives in a capability-based acquisition strategy. A particular problem occurs in cases where requirements on systems are evolving. In this paper, a Bayesian Network (BN) method is presented, which models requirement evolution in the midst of system interdependencies. The method analyzes the cascading effects of requirement and systems interdependencies on risk. A primary output of the approach is the identification of both critical systems and requirements. A synthetic problem is solved to demonstrate the proposed method.

Acquisition Management for System-of-Systems: Requirement Evolution and Acquisition Strategy Planning

Seung Yeob Han; Zhemei Fang; Daniel DeLaurentis
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Tipo: Conferência ou Objeto de Conferência
Relevância na Pesquisa
45.97%
Symposium Presentation (for Acquisition Research Program)

An analysis of the defense acquisition strategy for unmanned systems

Jones, Courtney David
Fonte: Monterey, California: Naval Postgraduate School Publicador: Monterey, California: Naval Postgraduate School
Tipo: Tese de Doutorado
Relevância na Pesquisa
46.1%
Approved for public release; distribution is unlimited.; In the past 12 years of sustained conflict, the Department of Defense (DoD) has procured thousands of unmanned systems, from ordnance disposal robots to airborne surveillance platforms to unmanned cargo helicopters. These assets have saved countless lives and have become critical to DoD strategy. The health of the U.S. robotics industry must become a national strategic imperative in order to maintain technology dominance. The cyclical nature of DoD funding inevitably results in industry expansion and consolidation. The unmanned systems industry will be subject to consolidation pressures. Keeping unmanned system cost-per-copy low is critical; thus, economies of scale should be highly valued. However, premature robotics industry consolidation could threaten innovation and competition that will be critical for the U.S. military to maintain its dominance. With impending budget reductions, there will be increasing pressure to narrow down on robotics technologies to achieve efficiencies and reduce costs. However, to maintain the health of the robotics industry, the acquisition strategy must be contingent on the evolution of industry. This thesis examines the defense robotics industry and historical technology S-curves for comparable industries and evaluates unmanned system acquisition strategies.

Sea water air conditioning (SWAC) at Naval Base Guam: cost-beneit analysis and acquisition strategy

Crisson, Kevin; Grammar, Jason; Leestma, Peter
Fonte: Monterey, California: Naval Postgraduate School Publicador: Monterey, California: Naval Postgraduate School
Tipo: Tese de Doutorado
Relevância na Pesquisa
45.96%
Approved for public release; distribution is unlimited; The purposes of this research are to determine whether it is financially feasible and attractive to install sea water air conditioning (SWAC) at Naval Base (NB) Guam, which the Naval Facilities Engineering Command currently deems to be true; to develop an acquisition strategy that NB Guam would be able to use to procure a SWAC system; and to identify any environmental obstacles associated with installing a SWAC system at NB Guam. This includes environmental impact studies and potential long-term schedule effects of environmental research. This research provides the analytic underpinning for the SWAC-driven reduction of electricity consumption at a significant number of naval facilities, and it provides a significant contribution towards meeting the Secretary of the Navy’s renewable energy goals.

An Analysis of the Defense Acquisition Strategy for Unmanned Systems

Jones, Courtney D.; Naval Postgraduate School Acquisition Research Program
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Tipo: Poster
Relevância na Pesquisa
56.14%
Annual Acquisition Research Symposium batch 2; Annual Acquisition Research Symposium; With impending budget reductions, there will be increasing pressure to narrow down on robotics technologies to achieve efficiencies and reduce costs. However, to maintain the health of the robotics industry, the acquisition strategy must be contingent on the evolution of industry. This thesis examines the defense robotics industry and historical technology S-curves for comparable industries and evaluates unmanned system acquisition strategies.

Implementing coordinative acquisition as a viable streamlined acquisition process in the Department of Defense (DoD): will contractors participate?

Froemke, Charles B.; Tanner, Jerry M.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Formato: xiv, 71 p. : col. ill.; 28 cm.
Relevância na Pesquisa
46.12%
MBA Professional Report; The purpose of this MBA Project is to discuss the use of the coordinative acquisition tool, which supports Defense Acquisition Performance Assessment (DAPA) recommendations calling for more streamlined acquisition architecture. Specifically, we conduct an analysis of the coordinative acquisition strategy as presented by Dr. Joseph P. Avery in his January 2006 presentation entitled, "Coordinative Acquisition Strategies; Hyperswift Response to the Warfighter" as an acquisition tool used outside of the Federal Acquisition Regulation (FAR). We compare this method to DoD Directive 5000.1, DAPA, and other acquisition policies calling for acquisition cycle-time reduction and for a more simplified acquisition architecture. We also conduct a case study on the Rapid Identification Friend or Foe (RIFF) test kit prototype and develop lessons learned as it relates to DoD-wide implementation of coordinative acquisition as a viable streamlined acquisition tool for rapid acquisition of immature technologies necessary for warfighter support. We also discuss interviews with Government and industry representatives at all levels in order to better explore legal and ethical considerations of coordinative acquisition. Feedback from these interviews provides useful insight into industry's actual willingness to accept this form of acquisition for future projects within the DoD.; US Air Force (USAF) authors.

Five Key Changes for the Management of UK Defence'An Agenda for Research?

Peter Tatham; Trevor Taylor
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Tipo: Relatório
Relevância na Pesquisa
45.97%
Proceedings Paper (for Acquisition Research Program); This paper is conceptual in nature and reviews five of the key management challenges facing those charged with the management of the UK Defence. It is argued that similar challenges face many Western governments, albeit the solutions are likely to be country-specific. Given the paucity of academic research into the general area of defence management, it is suggested that there is considerable potential for focused application of ideas and concepts from a broad range of disciplines that will help improve the UK''s ability to maintain its peacetime military capability efficiently whilst retaining its capacity to conduct operations effectively. Whilst the paper does not seek to recommend solutions for the issues identified, it does seek to expose the essential features as a means of broadening the understanding of the nature of the challenge''and, hence, to help shape the research agenda.; Acquisition Research Program

Development of the improved Army aircraft survivability equipment (ASE) acquisition strategy through economic analysis and emerging procurement philosophies

Flores, Edgar E.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: 66 p.
EN_US
Relevância na Pesquisa
46.22%
This thesis examines the previous acquisition strategy of a typical aircraft survivability equipment (ASE) procurement through an economic analysis. It also explores new philosophies to traditional acquisition methods and combines the economic lessons learned to suggest improvements to the current ASE procurement strategy. The AN/APR-39A(V)l Radar System Detecting Set (RSDS) was analyzed because it represented, on average, the common approach to acquiring ASE in prior years. After analyzing this system's cost data by using the Learning Rate (LR) Theory, and comparing it to the Should Cost Analysis Team's (SCAT) cost estimation, it appeared that actual costs did not follow the agreed upon 90% LR. A closer examination concluded that a 90% LR was used, but price discrepancies to the LR estimations were caused by an innovative payment scheme. New approaches to systems acquisition, along with the appropriate use of the LR and payment methods can enhance the acquisition process. This thesis recommends selected new procurement philosophies for an improved ASE strategy.; NA; NA; U.S. Army (U.S.A.) author.

Analyzing the multi-national cooperative acquisition aspect of the Joint Strike Fighter (JSF) Program

Ozdemir, Levent
Fonte: Monterey, California: Naval Postgraduate School Publicador: Monterey, California: Naval Postgraduate School
Formato: xviii, 115 p. : ill. ; 28 cm.
Relevância na Pesquisa
56.3%
Approved for public release, distribution unlimited; MBA Professional Report; The JSF program is a cooperative acquisition program involving the U.S. and eight partner nations to design, develop, and produce a next-generation fighter. Although the program is led by the U.S., the participant nations cooperate to produce an affordable yet advanced aircraft by exchanging technology and information, as well as investing in the program and receiving commensurate returns. The allied nations will then possess an advanced aircraft that they could not afford to develop on their own. Therefore, in order to successfully execute this complicated aircraft program, the U.S. has implemented an unprecedented acquisition strategy that it envisages as a model for cooperation in future international programs. The best value approach, international partners' early involvement, and leveled program participation are salient features of this strategy. However, even with innovative approaches and strong management efforts, the program's unit cost has increased 50 percent since 2001, with schedule delays of 2.5 years. In order to understand this complexity, this report analyzes the JSF program's international cooperative acquisition strategy. Specifically...

The Theater High Altitude Area Defense program: an interim examination of its acquisition strategy

Atkinson, James W.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: 82 p.
EN_US
Relevância na Pesquisa
66.23%
Approved for public release; distribution in unlimited.; This thesis is an examination of the Theater High Altitude Area Defense (THAAD) program's implementation of the User Operational Evaluation System (UOES) acquisition strategy. The Missile Defense Act of 1991 imposed significant schedule risk on THAAD's development, necessitating the UOES strategy. The UOES risk management issues are analyzed using DOD's risk management guidance. This guidance incorporates some current methods, applications, and trends in using prototypes during development. Using this guidance, THAAD's tailored acquisition strategy is reviewed. From this review, lessons that have been learned from the program's experience are developed. The results show that as a result of programmatic risk the UOES strategy has resulted in a delay in fielding the full THAAD objective system.; http://www.archive.org/details/theaterhighaltit00atki; Captain, United States Army

Developing an acquisition strategy for the Colombian Navy's new strategic surface ships

Cubillos Chacon, Orlando A.
Fonte: Monterey California. Naval Postgraduate School Publicador: Monterey California. Naval Postgraduate School
Formato: xvi, 75 p. : ill. ; 28 cm.
Relevância na Pesquisa
56.24%
MBA Professional Report; The Colombian Navy is a modern, disciplined, and well-trained military service performing the constitutional mission to defend the integrity of the Colombian maritime territory and enforce government policies concerning the use of the sea. Today the strategic fleet fulfilling these duties bears normal aging problems threatening the execution of the Colombian Navy's mission in the near future. The country's fiscal situation is tight and no funds are budgeted to support a contract acquiring new ships. The Colombian Navy will need to replace its strategic surface ships in order to upgrade its tactical capabilities to new technology. The most viable option is the acquisition of second-hand ships available on the international market. The U.S. defense acquisition system has been in place for almost sixty years and has proven its efficiency by providing defense systems to the U.S. military services; therefore, after conducting a comprehensive literature search and bibliographic review, the U.S. DoD acquisition strategy was the model selected for a proposed acquisition strategy suitable for the Colombian Navy's unique conditions,. The resulting product, recommendations, concerns, and areas of further research coincide with the need to develop a flexible and reliable acquisition system to face the future of progress within the Colombian Navy.

A Critical Examination of the DoD's Business Management Modernization Program

Christopher Hanks
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Tipo: Relatório
Relevância na Pesquisa
46%
Proceedings Paper (for Acquisition Research Program); In its efforts to improve operations in what it has designated the five business domains in the US Department of Defense (DoD)''acquisition, financial management, human resources management, installations & environment management, and logistics management''the DoD''s Business Management Modernization Program (BMMP) is a key element of the DoD''s ongoing efforts to transform itself. This paper argues that the BMMP needs to be fundamentally reoriented to meet its goals. It provides an historical overview, research evidence from other studies, and additional arguments to support that view and suggests three steps that could be taken to begin the proposed reorientation.; Acquisition Research Program

Acquisition workforce strategy: the challenge Defense (DOD) faces to improve its acquisition workforce

Chapple, Christopher W.; Faire, Michel J.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Formato: xviii, 85 p. : chiefly col. ill. ; 28 cm.
Relevância na Pesquisa
36.34%
The objective of this project is to examine the Defense's (DoD's) FY 2010 Acquisition Workforce Improvement Strategy. The project will outline developments that generated the need for DoD's Acquisition Workforce Improvement Strategy and DoD's efforts to address its acquisition workforce's ability to manage and oversee its services contracts. This project will also examine the implementation and effectiveness of DoD's Acquisition Workforce improvement initiatives to see if plans will meet intended higher-level directives. The result of this project will enhance acquisition personnel's understanding of the DoD's Acquisition Workforce Improvement Strategy and the initiatives that impact acquisition workforce.

The Avenger Air Defense System: an examination of the nondevelopmental item acquisition strategy

Stearns, Kenneth M.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: 85 p.;28 cm.
EN_US
Relevância na Pesquisa
46.26%
Approved for public release; distribution unlimited.; With the Department of Defense's (DoD) budget being reduced to ever diminishing levels, DoD acquisition managers must acquire technologically superior weapon systems within fixed time periods with the least amount of resources. One way they can effectively accomplish this is by using a Nondevelopmental Item (NDI) acquisition strategy. One weapon system program that has successfully used such an NDI strategy is the U.S. Army's Avenger Air Defense System Program. This thesis examines the DoD acquisition process and how NDIs are used within the process. The thesis then analyzes the Avenger Program and its NDI acquisition strategy to determine what factors made the program successful. From this analysis, lessons-learned are identified that can be used by other acquisition managers and their staffs to effectively manage future NDI programs. Significant lessons-learned indicate that high-level support, a thorough market investigation and a tailored acquisition process are critical to the success of an NDI program; http://archive.org/details/avengerairdefens00stea; Captain, United States Army

An analysis of the United States Marine Corps' Family of Ballistic Protective Systems Acquisition Strategy

Freeby, Jason S.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xvi, 49 p. : ill. ;
Relevância na Pesquisa
46.16%
Approved for public release, distribution unlimited; Recent congressional and media inquiries have highlighted questions regarding the protection provided to today's Marine Corps. The purpose of this research is to analyze the current Family of Ballistic Protective Systems (FBPS) Acquisition Strategy of the United States Marine Corps. The FBPS consists of individual protective items such as ballistic vests, individual armor plating, helmets, and eye and ear protection. Currently, the Marine Corps adheres to the (Department of Defense) DoD policy to use one-year appropriations to finance the procurement and sustainment of these items. Critics of the policy believe a separate three-year appropriation specific to the acquisition of these individual components better serves the customer and the acquisition process delineated in the DoD Instructions. The research examined current government regulations, policy environment, and acquisition precedents. Additionally, the research compared a previous FBPS acquisition to a theoretical procurement under three year appropriations. The research determined that the three-year obligation period of procurement funding better serves the acquisition process. Furthermore, three-year appropriations provide a better value for the Marine Corps in terms of cost savings and a better product. Finally...