560 research outputs found
Screening for Real Options âInâ an Engineering System: A Step Towards Flexible System Development
The goal of this research is to develop an analytical framework for screening for real options âinâ an
engineering system. Real options is defined in the finance literature as the right, but not the obligation, to
take an action (e.g. deferring, expanding, contracting, or abandoning) at a predetermined cost and for a
predetermined time. These are called "real options" because they pertain to physical or tangible assets,
such as equipment, rather than financial instruments. Real options improve a systemâs capability of
undergoing classes of changes with relative ease. This property is often called âflexibility.â Recently, the
DoD has emphasized the need to develop flexible system in order to improve operational, technical, and
programmatic effectiveness. The aim of this research is to apply real options thinking to weapon
acquisitions in order to promote the ability of weapon system programs to deftly avoid downside
consequences or exploit upside opportunities
Screening for Real Options âInâ an Engineering System: A Step Towards Flexible System Development; PART I: The Use of Design Matrices to Create an End-to-End Representation of a Complex Socio-Technical System
The goal of this research is to develop an analytical framework for screening for real options âinâ an engineering system. Real options is defined in the finance literature as the right, but not the obligation, to take an action (e.g. deferring, expanding, contracting, or abandoning) at a predetermined cost and for a predetermined time. These are called "real options" because they pertain to physical or tangible assets, such as equipment, rather than financial instruments. Real options improve a systemâs capability of undergoing classes of changes with relative ease. This property is often called âflexibility.â Recently, the DoD has emphasized the need to develop flexible system in order to improve operational, technical, and programmatic effectiveness. The aim of this research is to apply real options thinking to weapon acquisitions in order to promote the ability of weapon system programs to deftly avoid downside consequences or exploit upside opportunities.
The practice of real options in systems engineering is a nascent field of inquiry. One of the most significant challenges in applying real options to engineering systems is the problem of identifying the most efficacious points within the system to create options. In order to identify the points of interest, systems engineers require knowledge about the physical and non physical aspects of the system, insight into sources of change, and the ability to examine the dynamic behavior of the system. We propose a two-phase process to perform this analysis. The first phase is a system representation phase that seeks to create an end-to-end representation of engineering system that includes endogenous interactions across system views and interactions with a systems environment. The next phase is an analysis phase that models the evolution of the engineering system in order to identify the real options in the system. This paper presents the system representation phase and proposes a methodology for creating an end-to-end representation of an engineering system.
The methodology for representing an engineering system extends existing systems engineering and architecting methods in two dimensions. First, the framework couples traditional architecting views to represent traceability and endogenous interactions within an engineering system. Second, the framework includes views of the system not represented in traditional engineering frameworks that includes social networks and environmental interactions. The framework uses coupled Design Structure Matrices (DSM) to represent the traditional and new architecting views. The coupled DSMs are organized into an Engineering System Matrix (ESM), which is a holistic representation of an engineering system that captures all of the critical variables and causal interactions across architectural elements. The result is an analytic framework that captures the qualitative understanding of the system into a single view that is conducive for deep quantitative inquiry.
This paper presents a discussion of pertinent literature, an overview of the ESM framework and underlying theory. In addition, this paper previews ongoing research using the ESM to identify options for a mini-air vehicle (MAV) weapon development system
Paraganglioma of the tongue with SDHB gene mutation in a patient with Graves' disease
The authors want to thank Mr. Jose Eduardo Matos (photog-rapher) for his technical assistance.We report a case of an apparently sporadic paraganglioma of the tongue with a germ-line mutation in a female patient with asymptomatic Graves' disease. The tongue is an unusual primary location. Genetic testing is mandatory in all cases. Thyroid gland dysfunction and autoimmune phenomena could be associated with some paragangliomas.S
Observation of edge magnetoplasmon squeezing in a quantum Hall conductor
Squeezing of the quadratures of the electromagnetic field has been
extensively studied in optics and microwaves. However, previous works focused
on the generation of squeezed states in a low impedance () environment. We report here on the demonstration of the squeezing of
bosonic edge magnetoplasmon modes in a quantum Hall conductor whose
characteristic impedance is set by the quantum of resistance (), offering the possibility of an enhanced coupling to low-dimensional
quantum conductors. By applying a combination of dc and ac drives to a quantum
point contact, we demonstrate squeezing and observe a noise reduction 18\%
below the vacuum fluctuations. This level of squeezing can be improved by using
more complex conductors, such as ac driven quantum dots or mesoscopic
capacitors.Comment: 6+2 pages, 3+1 figure
Humanized H19/Igf2 locus reveals diverged imprinting mechanism between mouse and human and reflects SilverâRussell syndrome phenotypes
Genomic imprinting is essential for mammalian development. Curiously, elements that regulate genomic imprinting, the imprinting control regions (ICRs), often diverge across species. To understand whether the diverged ICR sequence plays a species-specific role at the H19/insulin-like growth factor 2 (Igf2) imprinted locus, we generated a mouse in which the human ICR (hIC1) sequence replaced the endogenous mouse ICR. We show that the imprinting mechanism has partially diverged between mouse and human, depending on the parental origin of the hIC1 in mouse. We also suggest that our mouse model is optimal for studying the imprinting disorders BeckwithâWiedemann syndrome when hIC1 is maternally transmitted, and SilverâRussell syndrome when hIC1 is paternally transmitted
Phase appearance or disappearance in two-phase flows
This paper is devoted to the treatment of specific numerical problems which
appear when phase appearance or disappearance occurs in models of two-phase
flows. Such models have crucial importance in many industrial areas such as
nuclear power plant safety studies. In this paper, two outstanding problems are
identified: first, the loss of hyperbolicity of the system when a phase appears
or disappears and second, the lack of positivity of standard shock capturing
schemes such as the Roe scheme. After an asymptotic study of the model, this
paper proposes accurate and robust numerical methods adapted to the simulation
of phase appearance or disappearance. Polynomial solvers are developed to avoid
the use of eigenvectors which are needed in usual shock capturing schemes, and
a method based on an adaptive numerical diffusion is designed to treat the
positivity problems. An alternate method, based on the use of the hyperbolic
tangent function instead of a polynomial, is also considered. Numerical results
are presented which demonstrate the efficiency of the proposed solutions
Recognition without identification, erroneous familiarity, and déjà vu
Déjà vu is characterized by the recognition of a situation concurrent with the awareness that this recognition is inappropriate. Although forms of déjà vu resolve in favor of the inappropriate recognition and therefore have behavioral consequences, typical déjà vu experiences resolve in favor of the awareness that the sensation of recognition is inappropriate. The resultant lack of behavioral modification associated with typical déjà vu means that clinicians and experimenters rely heavily on self-report when observing the experience. In this review, we focus on recent déjà vu research. We consider issues facing neuropsychological, neuroscientific, and cognitive experimental frameworks attempting to explore and experimentally generate the experience. In doing this, we suggest the need for more experimentation and amore cautious interpretation of research findings, particularly as many techniques being used to explore déjà vu are in the early stages of development.PostprintPeer reviewe
Global potential energy surface for the O2 + N2 interaction. Applications to the collisional, spectroscopic, and thermodynamic properties of the complex
A detailed characterization of the interaction between the most abundant
molecules in air is important for the understanding of a variety of phenomena
in atmospherical science. A completely {\em ab initio} global potential energy
surface (PES) for the O + N interaction is
reported for the first time. It has been obtained with the symmetry-adapted
perturbation theory utilizing a density functional description of monomers
[SAPT(DFT)] extended to treat the interaction involving high-spin open-shell
complexes. The computed interaction energies of the complex are in a good
agreement with those obtained by using the spin-restricted coupled cluster
methodology with singles, doubles and noniterative triple excitations
[RCCSD(T)]. A spherical harmonics expansion containing a large number of terms
due to the anisotropy of the interaction has been built from the {\em ab
initio} data. The radial coefficients of the expansion are matched in the long
range with the analytical functions based on the recent {\em ab initio}
calculations of the electric properties of the monomers [M. Bartolomei et al.,
J. Comp. Chem., {\bf 32}, 279 (2011)]. The PES is tested against the second
virial coefficient data and the integral cross sections measured with
rotationally hot effusive beams, leading in both cases to a very good
agreement. The first bound states of the complex have been computed and
relevant spectroscopic features of the interacting complex are reported. A
comparison with a previous experimentally derived PES is also provided
Epileptic networks in focal cortical dysplasia revealed using electroencephalography-functional magnetic resonance imaging.
Surgical treatment of focal epilepsy in patients with focal cortical dysplasia (FCD) is most successful if all epileptogenic tissue is resected. This may not be evident on structural magnetic resonance imaging (MRI), so intracranial electroencephalography (icEEG) is needed to delineate the seizure onset zone (SOZ). EEG-functional MRI (fMRI) can reveal interictal discharge (IED)-related hemodynamic changes in the irritative zone (IZ). We assessed the value of EEG-fMRI in patients with FCD-associated focal epilepsy by examining the relationship between IED-related hemodynamic changes, icEEG findings, and postoperative outcome
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