257 research outputs found
Doi moi in the mountains : land use changes and farmers' livelihood strategies in Bac Kan Province, Viet Nam
Верифікація підсумкових ранжувань, отриманих внаслідок експертного оцінювання
In the modern dynamic information society, situations that are characterized by complexity, multifactoriality, uncertainty, and non-formalization occur very often. Under such conditions, the adoption of effective management decisions is impossible without interaction with the expert environment. This applies to a wide range of human activities, including economic issues. The article is devoted to one of the key stages of expert evaluation – the analysis of members of expert commissions’ judgments and drawing up final conclusions. The author aims to get closer to solving one of the key problems characteristic to this stage, namely: truth verification problems, reliability confirmation for final conclusions obtained as a result of generalization of expert groups’ work. Most often, the experts are asked to compare certain objects according to certain criteria, to identify the best and the worst among them. It is clear that expert judgments are rarely unanimous. Therefore, it is important to apply scientific approaches to constructing final ranking, that is, the final location of objects in order of increase or decrease of a certain quality or usability. The mathematical modeling of activity of an expert group conducted by the author of the article made it possible to identify cases where, depending on the applied techniques, the final rankings obtained on the basis of the judgments of the same experts may differ (sometimes even substantially). This again emphasizes the need to verify the final rankings. The advantages and disadvantages of applying quantitative and qualitative methods in expert-analytical activity are also considered. The scientific novelty of the conducted research is to improve the methodological approaches that will allow to improve the consistency of expert judgments, and to develop recommendations for the complex application of separate methods for constructing total ranking. The article is intended for scientists and practitioners who are interested in contemporary sociological and management approaches to solving economic problems. Also, the article may be useful for specialists and programmers who work in the field of development of artificial intelligence.У сучасному динамічному інформаційному суспільстві дуже часто виникають ситуації, які характеризуються складністю, багатофакторністю, невизначеністю, неформалізованістю. За таких умов ухвалення ефективних управлінських рішень є неможливим без взаємодії з експертним середовищем. Це стосується найрізноманітніших сфер людської діяльності, у тому числі й економічних питань. Стаття присвячена одній з ключових стадій експертного оцінювання – аналізу суджень членів експертних комісій. виробленню остаточних висновків. Автор ставить за мету наблизитись до розв’язання однієї з ключових проблем, притаманних цій стадії, а саме: проблеми перевірки істинності, підтвердження достовірності тих остаточних висновків, які отримуються в результаті узагальнення роботи експертних груп. Найчастіше перед експертами ставиться завдання порівняти за визначеними критеріями певні об’єкти, виявити найкращі та найгірші серед них. Зрозуміло, що експертні судження нечасто виявляються одностайними. Тому важливо застосувати наукові підходи до побудови підсумкових ранжувань, тобто заключного розташування об’єктів в порядку зростання чи спадання певної якості чи придатності до застосування. Проведене автором статті математичне моделювання діяльності експертної групи дозволило виявити випадки, коли в залежності від застосованих методик підсумкові ранжування, отримані на основі суджень одних і тих же експертів, можуть відрізнятись (часом навіть суттєво). Це ще раз підкреслює необхідність верифікації підсумкових ранжувань. Також розглядаються переваги та недоліки застосування кількісних і якісних методів в експертно-аналітичній діяльності. Наукова новизна проведених досліджень полягає у вдосконаленні методологічних підходів, які дозволять покращити узгодженість експертних суджень, і виробленні рекомендацій стосовно комплексного застосування окремих методів побудови підсумкових ранжувань. Стаття призначена для науковців та практиків, яких цікавлять сучасні соціологічні та управлінські підходи до вирішення економічних проблем. Також стаття може бути корисною для фахівців та програмістів, які працюють у сфері розроблення штучного інтелекту
Magnetic properties and magnetostructural phase transitions in Ni2+xMn1-xGa shape memory alloys
A systematic study of magnetic properties of Ni2+xMn1-xGa (0 \le x \le 0.19)
Heusler alloys undergoing structural martensite-austenite transformations while
in ferromagnetic state has been performed. From measurements of spontaneous
magnetization, Ms(T), jumps \Delta M at structural phase transitions were
determined. Virtual Curie temperatures of the martensite were estimated from
the comparison of magnetization in martensitic and austenitic phases. Both
saturation magnetic moments in ferromagnetic state and effective magnetic
moments in paramagnetic state of Mn and Ni atoms were estimated and the
influence of delocalization effects on magnetism in these alloys was discussed.
The experimental results obtained show that the shift of martensitic transition
temperature depends weakly on composition. The values of this shift are in good
correspondence with Clapeyron-Clausius formalism taking into account the
experimental data on latent heat at martensite-austenite transformations.Comment: 7 pages, 8 figure
Origin of four-fold anisotropy in square lattices of circular ferromagnetic dots
We discuss the four-fold anisotropy of in-plane ferromagnetic resonance (FMR)
field , found in a square lattice of circular Permalloy dots when the
interdot distance gets comparable to the dot diameter . The minimum
, along the lattice axes,
differ by 50 Oe at = 1.1. This anisotropy, not expected in
uniformly magnetized dots, is explained by a non-uniform magnetization
\bm(\br) in a dot in response to dipolar forces in the patterned magnetic
structure. It is well described by an iterative solution of a continuous
variational procedure.Comment: 4 pages, 3 figures, revtex, details of analytic calculation and new
references are adde
Magnetic Vortex Resonance in Patterned Ferromagnetic Dots
We report a high-resolution experimental detection of the resonant behavior
of magnetic vortices confined in small disk-shaped ferromagnetic dots. The
samples are magnetically soft Fe-Ni disks of diameter 1.1 and 2.2 um, and
thickness 20 and 40 nm patterned via electron beam lithography onto microwave
co-planar waveguides. The vortex excitation spectra were probed by a vector
network analyzer operating in reflection mode, which records the derivative of
the real and the imaginary impedance as a function of frequency. The spectra
show well-defined resonance peaks in magnetic fields smaller than the
characteristic vortex annihilation field. Resonances at 162 and 272 MHz were
detected for 2.2 and 1.1 um disks with thickness 40 nm, respectively. A
resonance peak at 83 MHz was detected for 20-nm thick, 2-um diameter disks. The
resonance frequencies exhibit weak field dependence, and scale as a function of
the dot geometrical aspect ratio. The measured frequencies are well described
by micromagnetic and analytical calculations that rely only on known properties
of the dots (such as the dot diameter, thickness, saturation magnetization, and
exchange stiffness constant) without any adjustable parameters. We find that
the observed resonance originates from the translational motion of the magnetic
vortex core.Comment: submitted to PRB, 17 pages, 5 Fig
Soliton pair dynamics in patterned ferromagnetic ellipses
Confinement alters the energy landscape of nanoscale magnets, leading to the
appearance of unusual magnetic states, such as vortices, for example. Many
basic questions concerning dynamical and interaction effects remain unanswered,
and nanomagnets are convenient model systems for studying these fundamental
physical phenomena. A single vortex in restricted geometry, also known as a
non-localized soliton, possesses a characteristic translational excitation mode
that corresponds to spiral-like motion of the vortex core around its
equilibrium position. Here, we investigate, by a microwave reflection
technique, the dynamics of magnetic soliton pairs confined in lithographically
defined, ferromagnetic Permalloy ellipses. Through a comparison with
micromagnetic simulations, the observed strong resonances in the subgigahertz
frequency range can be assigned to the translational modes of vortex pairs with
parallel or antiparallel core polarizations. Vortex polarizations play a
negligible role in the static interaction between two vortices, but their
effect dominates the dynamics.Comment: supplemental movies on
http://www.nature.com/nphys/journal/v1/n3/suppinfo/nphys173_S1.htm
Low-loss Si-based Dielectrics for High Frequency Components of Superconducting Detectors
Silicon-based dielectric is crucial for many superconducting devices,
including high-frequency transmission lines, filters, and resonators. Defects
and contaminants in the amorphous dielectric and at the interfaces between the
dielectric and metal layers can cause microwave losses and degrade device
performance. Optimization of the dielectric fabrication, device structure, and
surface morphology can help mitigate this problem. We present the fabrication
of silicon oxide and nitride thin film dielectrics. We then characterized them
using Scanning Electron Microscopy, Atomic Force Microscopy, and
spectrophotometry techniques. The samples were synthesized using various
deposition methods, including Plasma-Enhanced Chemical Vapor Deposition and
magnetron sputtering. The films morphology and structure were modified by
adjusting the deposition pressure and gas flow. The resulting films were used
in superconducting resonant systems consisting of planar inductors and
capacitors. Measurements of the resonator properties, including their quality
factor, were performed.Comment: 4 pages, 5 figures, conferenc
Failure of noninvasive prediction of pulmonary hypertension in patients with idiopathic pulmonary fibrosis
Background. Pulmonary hypertension (PH) in patients with advanced idiopathic pulmonary fibrosis (IPF) is a complication connected with unfavorable prognosis. Great efforts have been made in attempting to establish a reliable non-invasive method which would enable detection of this complication. In this context a formula using pulmonary function parameters was published with outstanding results. Methods. We tested the formula in 27 IPF patients who underwent a lung function examination, cardiac ultrasonography and catheterisation on the same day. Results. Pulmonary hypertension was detected by catheterisation in 17 patients (63%). In our group, contrary to the published data, the aforementioned formula was neither useful for detecting patients with a high probability of PH nor as a means of calculating the mean pulmonary artery pressure in individual patients (p=0.502 and p=0.833, respectively). Ultrasound examination reached borderline correlation with the values measured by catheterisation when we compare patients with relevant results (r=0.531, p=0.051). However, the examination gave no usable results in 13 patients (48%). Conclusion. Our data suggests that no reliable, noninvasive method is currently available for detecting and confirming PH in IPF patients. We did not confirm the usefulness of the published formula. Further carefully organised studies will be necessary to verify or refute it
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