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1

Energy Harvesting From Bistable Systems Under Random Excitation

Lentz L., Nguyen H. T., von Wagner U.

Machine Dynamics Research

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2017

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Vol. 41, No. 1

5--16

EN

The transformation of otherwise unused vibrational energy into electric energy through the use of piezoelectric energy harvesting devices has been the subject of numerous investigations. The mechanical part of such a device is often constructed as a cantilever beam with applied piezo patches. If the harvester is designed as a linear resonator the power output relies strongly on the matching of the natural frequency of the beam and the frequency of the harvested vibration which restricts the applicability since most vibrations which are found in built environments are broad-banded or even totally random. A possible approach to overcome this restriction is the use of permanent magnets to impose a nonlinear restoring force on the beam that leads to a broader operating range due to large amplitude motions over a large range of excitation frequencies. In this paper such a system is considered introducing a refined modeling with multiple spacial ansatz functions and a refined modeling of the magnet beam interaction. The corresponding probability density function in case of random excitation is calculated by the solution of the corresponding Fokker-Planck equation and compared with results from Monte Carlo simulations. Finally some measurements of ambient excitations are discussed.

2

Synthesis and Analysis of Product-form Petri Nets

Haddad S., Mairesse J., Nguyen H. T.

Fundamenta Informaticae

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2013

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Vol. 122, nr 1-2

147--172

EN

For a large Markovian model, a "product form" is an explicit description of the steadystate behaviour which is otherwise generally untractable. Being first introduced in queueing networks, it has been adapted to Markovian Petri nets. Here we address three relevant issues for product-form Petri nets which were left fully or partially open: (1) we provide a sound and complete set of rules for the synthesis; (2) we characterise the exact complexity of classical problems like reachability; (3) we introduce a new subclass for which the normalising constant (a crucial value for product-form expression) can be efficiently computed.

3

Effective energy integral functionals for thin films in the Orlicz-Sobolev space setting

Laskowski W., Nguyen H. T.

Demonstratio Mathematica

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2013

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Vol. 46, nr 3

585--604

EN

We consider an elastic thin film as a bounded open subset ω of R2. First, the effective energy functional for the thin film ω is obtained, by Γ-convergence and 3D-2D dimension reduction techniques applied to the sequence of re-scaled total energy integral functionals of the elastic cylinders (…) as the thickness ε goes to 0. Then we prove the existence of minimizers of the film energy functional. These results are proved in the case when the energy density function for the elastic cylinders has the growth prescribed by an Orlicz convex function M. Here M is assumed to be non-power-growth-type and to satisfy the conditions (…) and (…) (that is equivalent to the reflexivity of Orlicz and Orlicz–Sobolev spaces generated by M). These results extend results of H. Le Dret and A. Raoult for the case M(t) = (…) for some (…).

4

Using Web 2.0 in cultural immersive health education

Nguyen H. T.

Bio-Algorithms and Med-Systems

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2010

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Vol. 6, no. 11

73--78

EN

Developing empathy is one of several key principles in working in general practice and is of particular importance in the cross-cultural environment. Arguably it is more difficult to empathize with patients from another culture whose viewpoint differs based on their cultural and social experiences. Cultural immersion and plunges is a well-researched and documented approach in solving the issues of empathy and cross-cultural interactions. Cultural immersion involves participants being placed in an unfamiliar cultural environment ; and participants are guided to reflect on their experiences through proposed activities before, during and after the immersion event. This paper will outline and discuss: 1. The cultural immersive activities at NTGPE for health students, junior doctors and GP registrars in Australian Aboriginal communities 2. The use of Web 2.0 also know as the "social web" to allow learners to generate, publish and share content more easily including reflective writing which are crucial in cultural competence training.

5

Modele społecznej odpowiedzialności przedsiębiorstw

Nguyen H. T.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Nauki Ekonomiczne

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2008

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Z. 9

179--194

PL

Problem odpowiedzialności społecznej przedsiębiorstwa jest znany i dobrze przebadany w literaturze nauki zarządzania. Istota tej problematyki opiera się na dwóch przeciwnych, krańcowych koncepcjach odpowiedzialności: finansowej i społecznej. Wraz z rozwojem zarządzania w kierunku zarządzania społecznego odbywającego się w coraz bardziej złożonym, turbulentnym otoczeniu społeczno-gospodarczym powoli narasta znaczenie koncepcji społecznej jako wyznacznika sukcesu w zarządzaniu przedsiębiorstwem.

EN

Corporate Social Responsibility (CSR) is a problem well-known and deeply explored in the literature of management science. The essence of this problem is based on the two contradictory, marginal conceptions of CSR: financial and social. Together with the development of management science toward the social management that is taking place in a very complex and turbulent social-economic environment the important of social concept as a determinant of success in enterprise management slowly arises.

6

The Young measure representation for weak cluster points of sequences in M-spaces of measurable functions

Nguyen H. T., Pączka D.

Bulletin of the Polish Academy of Sciences. Mathematics

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2008

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Vol. 56, no 2

109-120

EN

Let (X, Y) be a duality pair of M-spaces X, Y of measurable functions from Ω ⊂ R[sup]n into R[sup]d. The paper deals with Y-weak cluster points φ of the sequence φ(•, z[sub]j(•)) in X, where z[sub]j: Ω→ R[sup]m is measurable for j ∈ N and φ: Ω x R[sup]m → R[sup]d is a Carathéodory function. We obtain general sufficient conditions, under which, for some negligible set Aφ, the integral I(φ,νx) := ∫R φ(x,λ) dνx(λ) exists for χ ∈ Ω \ Aφ and φ(x) = I(φ, νx) on Ω \ Aφ, where ν = {νx}x∈Ω is a measurable-dependent family of Radon probability measures on R[sup]m.

7

The advantages of function point method in the cost estimation of systems analysis and design

Nguyen H. T.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Nauki Ekonomiczne

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2007

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Z. 3

96--104

EN

This article describes the Function Method and discusses its strategic advantages for cost estimation of systems analysis and design in the background of other traditional methods of estimation. Of course there are no roses without thorn. The article recommends this method as a principle tool for labor cost estimation but also shows the shadows side of it to be avoided in some circumstances, in case of some types of specific technology.

PL

Referat opisuje metodę funkcyjną i dyskutuje nad jej strategicznymi przewagami w estymacji kosztów analizy i projektowania systemów na tle innych tradycyjnych metod estymacji. Oczywiste jest, że nie ma róży bez kolców. Referat rekomenduje ową metodę jako zasadnicze narzędzie w estymacji kosztów zasobów ludzkich, równocześnie jej ciemne strony do unikania w niektórych okolicznościach, w przypadku sytuacjach niektórych typów specyficznych technologii.

8

Model zarządzania zmianami a skuteczność praktycznego zarządzania przedsiębiorstwem

Nguyen H. T., Nogalski B.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Nauki Ekonomiczne

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2007

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Z. 3

131--140

PL

Dzisiejsze zmiany są zbyt złożone i wymagają zarządzania. W zarządzaniu nimi przydatny może być model zarządzania zmianami. Niniejszy referat jest próbą rozszerzenia pierwotnego modelu zarządzania zmianami Van de Vena i Poole’a na podstawie analizy zmian we współczesnych teoriach zarządzania i analizy przypadków zmian. Powstały model zintegrowany będzie odzwierciedlać mechanizmy zachodzących zmian i może stanowić dla menedżera narzędzie zarządzania zmianami, wspierające we właściwym podejmowaniu decyzji, wdrażaniu efektywnych strategii zmian pozwalających osiągnąć oczekiwane rezultaty. Niniejszy referat jest także próbą weryfikacji użyteczność tego zintegrowanego modelu w praktycznym zarządzaniu przedsiębiorstwem.

EN

Today’s changes are quite complex and need to be managed. The model for change management may be useful in managing them. This hereby paper is an attempt to extend the primary Van de Ven and Poole’s change management model based on the analysis of changes in contemporary management theories and cases study of changes. The outcome integrated model will reflect the mechanisms of occurring changes and may constitute a change management tool for managers. That tool will support in making decision and implementation efficient change strategy that permit to attain the expected result. This paper also is an attempt to verify the usefulness of this integrated model in real-life management situations.

9

Analiza rozwoju banku VIB w świetle modelu zarządzania zmianami Van de Vena i Poole’a

Nguyen H. T., Kuc B. R.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Nauki Ekonomiczne

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2007

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Z. 3

240--252

PL

Model zarządzania zmianami Van de Vena i Poole’a jest uniwersalny pod względem przydatności w analizie zmian zarówno w teorii jak i w praktyce zarządzania. Niniejszy artykuł jest próbą jego niewielkiej modyfikacji na potrzeby analizy rozwoju wybranego banku w aspekcie zmian organizacyjnych, technologicznych, jak i indywidualnych postaw i wiedzy.

EN

The Van de Ven and Poole’a change management model is universal tool in respect of its usefulness in change analysis in both theories and practice. This paper is an attempt to modify it for the need of development analysis of selected bank in term of organizational, technological changes as well as individual attitudes and knowledge.

10

Carathéodory CM-selectors for oppositely semicontinuous multifunctions of two variables

Nguyen H. T., Juniewicz M., Ziemińska J.

Bulletin of the Polish Academy of Sciences. Mathematics

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2002

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Vol. 50, no 1

47--57

EN

We present a new joint selection theorem on the so-called Caratheodory CM-selections for oppositely semicontinuous (in x) multifunctions F and G of variables (t, x) [belongs to] T x X where T is a complete measurable space and X is a Polish space. This theorem unifies the known theorem on Caratheodory selections for the lower Caratheodory multifunction G and a general theorem on Caratheodory epsilon-approximate selections for the H-upper Caratheodory multifunction F. The latter theorems are "T-random" versions of Michael's theorem and Cellina's theorem, respectively.