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Interconnections

Distribution by Scientific Domains

Engineering	32%
Humanities and Social Sciences	15%
Polymers and Materials Science	9%
Life Sciences	9%
Business, Economics, Finance and Accounting	8%
Chemistry	7%
Medical Sciences	5%
Information Science and Computing	3%
Physics and Astronomy	2%
4 Other Domains	10%

Distribution within Engineering

Control Systems Technology	37%
Communication Technology	15%
General & Introductory Electrical & Electronics Engineering	9%

Selected Abstracts

The Effect of Intermetallic Compound on Shear Strength of Diffusion Soldered Interconnection

ADVANCED ENGINEERING MATERIALS, Issue 3 2006
J. Wojewoda
The mechanical properties of diffusion soldered Cu/Cu interconnections were examined. Application of the indium-tin eutectic alloy as a solder material and different manufacturing temperatures resulted in creation of the intermetallics in the interconnection area. The calculated cross-sections of the Cu-In-Sn diagram combined with Scanning Electron Microscopy investigation allowed for the detailed description of the joints before the shear test and after it. [source]

Further constructive results on interconnection and damping assignment control of mechanical systems: the Acrobot example

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 14 2006
Arun D. Mahindrakar
Abstract Interconnection and damping assignment passivity-based control is a controller design methodology that achieves (asymptotic) stabilization of mechanical systems endowing the closed-loop system with a Hamiltonian structure with a desired energy function,that qualifies as Lyapunov function for the desired equilibrium. The assignable energy functions are characterized by a set of partial differential equations that must be solved to determine the control law. A class of underactuation degree one systems for which the partial differential equations can be explicitly solved,making the procedure truly constructive,was recently reported by the authors. In this brief note, largely motivated by the interesting Acrobot example, we pursue this investigation for two degrees-of-freedom systems where a constant inertia matrix can be assigned. We concentrate then our attention on potential energy shaping and give conditions under which an explicit solution of the associated partial differential equation can be obtained. Using these results we show that it is possible to swing-up the Acrobot from some configuration positions in the lower half plane, provided some conditions on the robot parameters are satisfied. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Teaching Spirituality to Nurse Practitioner Students: The Importance of the Interconnection of Mind, Body, and Spirit

JOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS, Issue 3 2001
Margie Maddox EdD
SpirituaLism is dormant, not dead, Let us hope. How to revive it, to rekindle it into life, is the great question , Florence Nightingale PURPOSE To describe the author's experience in locating and implementing a spiritual assessment tool in teaching a first semester clinical nurse prac-titioner (NP) course. DATA SOURCES Selected articles and responses of NP students to the use of the tool. CONCLUSIONS A spiritual assessment is an important component of a comprehensive health assessment. The use of a formal structured protocol provides a framework for beginning students to become comfortable with sprirituality and spiritual assessments and to begin to recognize spiritual distress in clients. IMPLICATIONS FOR PRACTICE The protocol used in the course is very extensive and might not be practical in a busy practice setting. An alternative, 4-point assessment is provided. [source]

INFORMATION EXCHANGE AND COMPETITION IN COMMUNICATIONS NETWORKS,

THE JOURNAL OF INDUSTRIAL ECONOMICS, Issue 4 2008
CARLO CAMBINI
Interconnection; Access charges; Reception charges; Information exchange We develop a model of information exchange between calling parties. We characterize the equilibrium when two interconnected networks compete by charging both for outgoing and incoming calls. We show that networks have reduced incentives to use off-net price discrimination to induce a connectivity breakdown when calls originated and received are complements in the information exchange. This breakdown disappears if operators are allowed to negotiate reciprocal access charges. We also study the relationship between sending and receiving retail charges as a function of the level of access charges. We identify circumstances where private negotiations over access charges induce first-best retail prices. [source]

ChemInform Abstract: Replacement of Selenium by Antimony in MoSe2: Interconnection of the MoSbSe Layers by Sb,Sb Bonding.

CHEMINFORM, Issue 1 2001
Holger Kleinke
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Ooplasmic segregation in the zebrafish zygote and early embryo: Pattern of ooplasmic movements and transport pathways

DEVELOPMENTAL DYNAMICS, Issue 8 2010
Ricardo Fuentes
Abstract Patterns of cytoplasmic movements and organization of transport pathways were examined in live or fixed zygotes and early zebrafish embryos using a variety of techniques. The zygote blastodisc grows by accumulation of ooplasm, transported to the animal pole from distinct sectors of ecto- and endoplasm at different speeds and developmental periods, using specific pathways or streamers. Slow transport (5 ,m/min) occurs during the first interphase along short streamers, whereas fast transport (9.6,40 ,m/min) takes place during the first cleavage division along axial and meridional streamers. Interconnections between streamers allow cargoes to change their speed and final destination. A similar sequence of events occurs during the following divisions. A complex network of microtubules and actin filaments in the endo- and ectoplasm appears to be involved in the transport of inclusions and mRNAs. Actin-dependent intermittent pulsations provoked high-speed back-and-forth movements of cytoplasm that may contribute to redistribution of organelles and maternal determinants. Developmental Dynamics 239:2172,2189, 2010. © 2010 Wiley-Liss, Inc. [source]

Process Chain for Tailoring the Refractive Index of Thermoplastic Optical Materials using Ceramic Nanoparticles

ADVANCED ENGINEERING MATERIALS, Issue 6 2005
E. Ritzhaupt-Kleissl
Interconnections between active optical devices like laser diodes and polymer optical fibres are a crucial factor of optical damping due to coupling losses at the interfaces. Tailoring the refractive index of thermoplastic polymers can diminish these damping losses. The use of modified thermoplastics in an injection moulding process allows a high throughput and therefore a cost effective method for manufacturing passive optical parts with improved properties. [source]

Cover Picture: Fabrication and Electrical and Mechanical Properties of Carbon Nanotube Interconnections (Adv. Funct.

ADVANCED FUNCTIONAL MATERIALS, Issue 11 2005
Mater.
Abstract The fabrication of carbon nanotube (CNT) structures, including simple tube,tube connections, crossed junctions, T-junctions, zigzag structures, and even nanotube networks, has been achieved by cutting and soldering CNTs using electron-beam-induced deposition of amorphous carbon (a-C), as detailed in the work of Peng and co-workers on p.,1825. These CNT structures have been constructed with a high degree of control, and it is found that the electric conductance and mechanical strength of the junctions can be improved by the deposition of a-C and by increasing the contact area of the junctions. Individual carbon nanotubes (CNTs) have been cut, manipulated, and soldered via electron-beam-induced deposition of amorphous carbon (a-C) and using a scanning tunneling microscope inside a transmission electron microscope. All CNT structures, including simple tube,tube connections, crossed junctions, T-junctions, zigzag structures, and even nanotube networks, have been successfully constructed with a high degree of control, and their electrical and mechanical properties have been measured in situ inside the transmission electron microscope. It is found that multiple CNTs may be readily soldered together with moderate junction resistance and excellent mechanical resilience and strength, and the junction resistance may be further reduced by current-induced graphitization of the deposited a-C on the junction. [source]

Spin Echo Analysis of Restricted Diffusion under Generalized Gradient Waveforms for Spherical Pores with Relaxivity and Interconnections

ISRAEL JOURNAL OF CHEMISTRY, Issue 1-2 2003
Brett N. Ryland
The problem of restricted diffusion in spherical pores is examined under conditions of finite gradient pulse width in pulsed gradient spin echo (PGSE)-NMR experiments. Closed form analytic expressions are derived, and the case of interconnected pores is briefly examined. An expression, based on the pore hopping approximation, is presented that predicts the echo attenuation for diffusion between pores under any gradient waveform. [source]

Stromules: Mobile Protrusions and Interconnections Between Plastids

PLANT BIOLOGY, Issue 3 2001
J. C. Gray
Abstract: Stroma-filled tubules, recently named stromules, extend from the surface of plastids in most cell types and plant species examined. Stromules are highly dynamic structures, continuously and rapidly changing shape. They have been shown to interconnect plastids and permit the exchange of green fluorescent protein (GFP) between plastids. Stromules are enclosed by the inner and outer plastid envelope membranes and are 0.4 - 0.8 ,m in diameter and up to 65 ,m long. Movement of stromules is dependent on the actin cytoskeleton and the ATPase activity of myosin. Stromules are more abundant in cells containing a relatively small plastid volume and provide a means of enormously increasing the plastid surface area. Many important questions on the structure, function and mobility of stromules remain unanswered. [source]

Pro-family Organizations in Calgary, 1998: Beliefs, Interconnections and Allies,

CANADIAN REVIEW OF SOCIOLOGY/REVUE CANADIENNE DE SOCIOLOGIE, Issue 1 2001
Gillian Anderson
Dans cet article, nous comparons les convictions des différents groupes pro-famille de Calgary et nous préscntons la structure des liens qui unissent ces groupes. Les données, recueillies en 1998, proviennent de documents et d'entretiens semi-structurés avec les chefs de file de ces groupes. Nous abordons ici trois problèmes de recherche. Tout d'abord, nous examinons la teneur des relations entre groupes pro-famille et pro-vie. Tous les groupes pro-famille, même ceux qui se prononcent résolument contre l'avortement, se dis-tinguent des groupes pro-vie sur le plan tant organisational que politique. Ensuite, nous nous penchons sur le rôle des croyances chré-tiennes au sein du mouvement. Nous affirmons que, bien que les groupes chrétiens aient été dominants en 1998, la promotion, de la famille hétérosexuelle nucléaire, et non les questions de doctrine, a été fondamentale pour le mouvement. Enfin, nous examinons si le mouvement s'est scindé entre socioconservateurs et centristes, les centristes étant peu représentatifs en 1998. En outre, l'un des groupes présentant un profil centriste, la National Foundation for Family Research and Education, a tout fait pour légitimer du point de vue scientifique les arguments moraux des socioconservateurs en faveur de la famille. En conclusion, nous soutenons que le mouvement pro-famille à Calgary s'est éloigné de sa vocation initiale de contre-mouvement antiféministe. Dans l'avenir, la popularité du mouvement pro-famille au Canada dépendra peut-être des valeurs postféministes qu'il affichera. This paper presents a comparative study of the beliefs of pro-family organizations in Calgary and a structural mapping of organizational ties. Data were gathered in 1998 from documents and semi-structured interviews with group leaders. Three research problems are addressed. The first concerns the closeness of the relationship between pro-family and pro-life groups. We find that all pro-family groups, even those with strong anti-abortion convictions, were organizationally and politically distinctive from pro-life groups. The second problem considers the role of Christian beliefs in the movement. We ascertain that although Christian groups were dominant in 1998, promotion of the heterosexual nuclear family, not doctrinal issues, was fundamental to the movement. The third problem concerns whether the movement was bifurcated between social conservative and centrist segments. The centrist segment was quite weak in 1998. Furthermore, one of the groups with a centrist persona, the National Foundation for Family Research and Education, strove to supply scientific legitimation for social conservatives' moral claims about the family. In conclusion, the article argues that the pro-family movement in Calgary has broken free of its initial phase as an anti-feminist countermovement and suggests that the future popularity of pro-family advocacy in Canada will be proportional to the degree that it is couched in a post-feminist framework. [source]

Perceived collective continuity: seeing groups as entities that move through time

EUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 6 2007
Fabio Sani
This paper presents two studies, conducted in two different countries, investigating perceptions of ingroups as enduring, temporally persistent entities, and introduces a new instrument measuring ,perceived collective continuity' (PCC). In Study 1 we show that perceptions of ingroup continuity are based on two main dimensions: perceived cultural continuity (perceived continuity of norms and traditions) and perceived historical continuity (perceived interconnection between different historical ages and events). This study also allows the construction of an internally consistent PCC scale including two subscales tapping on these two dimensions. Study 2 replicates findings from the first study; it also reveals that PCC is positively correlated to a set of social identity-related measures (e.g., group identification and collective self-esteem), and that its effects on these measures are mediated by perceived group entitativity. Overall, these two studies confirm that PCC is an important theoretical construct, and that the PCC scale may become an important instrument in future research on group processes and social identity. Copyright © 2007 John Wiley & Sons, Ltd. [source]

A new transmission pricing approach for the electricity cross-border trade in the ASEAN Power Grid

EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 2 2007
C. Adsoongnoen
Abstract The electricity cross-border trade is presently introduced among the member countries of the Association of South East Asian Nations (ASEAN). The ASEAN Power Grid (APG) is a plan to interconnect transmission networks among the ASEAN countries to optimize the use of energy resources; to operate the power network in an efficient, economical, and reliable manner; and to provide a close relation among the member countries by electric power interconnection. Transmission pricing is one of the controversial tasks to achieve the APG objectives. In this paper, a transmission pricing method for the electricity cross-border trade based on a combination of postage stamp method and sensitivity indices is proposed. The postage stamp pricing is a uniform tariff expected to recover the project investments, and the operation and maintenance costs. With the combination of the postage stamp method and sensitivity indices, the proposed pricing method sends proper incentive signals to power traders, which are based on system usage and congestion management. To demonstrate its effectiveness, the proposed method is applied to a 12-bus test system. The nodal tariffs at the particular injecting points, payments of the users, and revenues of transmission owners are computed. The simulation results indicate that the proposed method ensures a recovery of the investment costs and the concurrent costs of operation and maintenance in an efficient, fair, and simple manner. Copyright © 2006 John Wiley & Sons, Ltd. [source]

An advanced methodology for steady-state security assessment of power systems

EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 4 2001
D. P. Popovic
The basic objective of this paper is to present the relevant aspects of an advanced methodology for steady-state security assessment of power systems. This methodology consists of the following relevant parts: procedure for forming the unified external network equivalents, with adaptive buffer system selection, procedure for fast contingency selection and simple method for the fast and sufficiently accurate assessment of dynamic variation of power system frequency during the time of its primary control. For the potentially critical contingency, the continuation of iterative procedure is performed. Full contingency analysis is based on specially developed method, which enables successive solution of the load-flow problem for a set of characteristic post-dynamic quasi-stationary states. The characteristics of the developed methodology are tested on the example of the existing electric power interconnection in the Balkans. [source]

IntServ6: an approach to support QoS over IPv6 wired and wireless networks

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 6 2008
Jhon J. Padilla
In this paper we propose a new approach for Quality of Service (QoS) support on Internet. This approach, named IntServ6, is based on the Integrated Services Architecture (ISA). It takes advantage of the IPv6 header flow label field to improve a set of the standard ISA properties such as reservations within tunnels, flows aggregation and interconnection with MPLS transport networks. IntServ6 can be used for QoS support in IPv6 wired and wireless networks. This paper describes the IntServ6 operation and performance evaluation over both environments. Evaluation results show that this approach has a better router performance with respect to the standard IntServ. Thus, IntServ6 reduces the mean packet delay and reduces the packet delay dependence with the mobility. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Polymer Photovoltaic Cells Based on Solution-Processable Graphene and P3HT

ADVANCED FUNCTIONAL MATERIALS, Issue 6 2009
Qian Liu
Abstract A soluble graphene, which has a one-atom thickness and a two-dimensional structure, is blended with poly(3-hexylthiophene) (P3HT) and used as the active layer in bulk heterojunction (BHJ) polymer photovoltaic cells. Adding graphene to the P3HT induces a great quenching of the photoluminescence of the P3HT, indicating a strong electron/energy transfer from the P3HT to the graphene. In the photovoltaic devices with an ITO/PEDOT:PSS/P3HT:graphene/LiF/Al structure, the device efficiency increases first and then decreases with the increase in the graphene content. The device containing only 10,wt % of graphene shows the best performance with a power conversion efficiency of 1.1%, an open-circuit voltage of 0.72,V, a short-circuit current density of 4.0,mA cm,2, and a fill factor of 0.38 under simulated AM1.5G conditions at 100,mW cm,2 after an annealing treatment at 160,°C for 10,min. The annealing treatment at the appropriate temperature (160,°C, for example) greatly improves the device performance; however, an annealing at overgenerous conditions such as at 210,°C results in a decrease in the device efficiency (0.57%). The morphology investigation shows that better performance can be obtained with a moderate content of graphene, which keeps good dispersion and interconnection. The functionalized graphene, which is cheap, easily prepared, stable, and inert against the ambient conditions, is expected to be a competitive candidate for the acceptor material in organic photovoltaic applications. [source]

Low cholesterol along with inflammation predicts morbidity and mortality in hemodialysis patients

HEMODIALYSIS INTERNATIONAL, Issue 2 2009
George TSIRPANLIS
Abstract Low and not high cholesterol seems to predict high mortality in hemodialysis (HD) patients. The confirmation of this reverse epidemiology as well as its possible interconnection with the increased inflammatory activity observed in this population is being explored in the present study. A group of 136 HD patients was prospectively studied for 2 years, and cardiovascular disease (CVD) as well as all-cause mortality and morbidity were recorded. Baseline lipid profile, inflammatory status, and patients' characteristics were studied as potential survival and hospitalization predictors. During the 24-month follow-up, 21 deaths (52.4% due to CVD) and 38 hospitalizations (55.3% due to CVD) were recorded. In multivariate Cox regression analysis, decreased interleukin-10 (IL-10) and decreased total serum cholesterol (TChol) were the only independent predictors of CVD mortality while C-reactive protein and decreased TChol predicted all-cause mortality. Interleukin-10 at baseline was 11.29 ± 21.49 vs. 5.51 ± 4.57 pg/mL (P<0.018) and TChol 167.37 ± 47.84 vs.122.04 ± 26.48 mg/dL (P<0.000) in survivors vs. nonsurvivors from CVD, while C-reactive protein at baseline was 9.37 ± 11.54 vs. 23.15 ± 18.76 mg/L (P<0.000) and TChol 169.26 ± 46.42 vs. 133.26 ± 46.33 mg/dL (P<0.003) in survivors vs. nonsurvivors from any cause of death. Using the same method of statistical analysis, IL-6 and decreased soluble gp130 (sgp130),an antagonist of IL-6 action,were found to be the only independent prognostic factors for hospitalization due to CVD while decreased soluble gp130 remained the sole predictor of hospitalization due to any cause. In conclusion, reverse epidemiology regarding cholesterol is confirmed in the present study. Furthermore, inflammatory activity also predicts, independently of or in conjunction with low-cholesterol, CVD and all-cause morbidity and mortality in HD patients. [source]

Development of Multiple Power Quality Supply System,

IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 5 2010
Keiichi Hirose Member
Abstract This paper describes the characteristics and performances of a multiple power quality supply system (MPQSS), which consists of power electronics-based voltage compensators and three types of distributed generators (DGs). Its original concept of a future power delivery system having different service levels to meet each customer or load requirement at the same time was proposed as Flexible, Reliable, and Intelligent Electrical eNergy Delivery System (FRIENDS). The effectiveness of the developed power system was measured during an actual field demonstration conducted in 2007 by the New Energy and Industrial Technology Development Organization (NEDO), Sendai, Japan. Its effectiveness in feeding four classes of alternative current (AC) and one of direct current (DC) power while meeting various customer requirements was confirmed. Some sets of test data and an analysis using the data indicate that the developed system meets all the requirements for DG-related plants and has additional benefits. The power system maintains voltage and frequency conditions without interruption in the every state, grid interconnection, islanding, and backup modes. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

On parameter estimation for excitation control of synchronous generators

INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 5 2004
Martha Galaz
Abstract This paper deals with the problem of identification of the network parameters and the desired equilibrium in applications of excitation control for synchronous generators. Our main contribution is the construction of a new non-linear identifier that provides asymptotically consistent estimates (with guaranteed transient bounds) of the line impedance and the equilibrium for the classical three-dimensional flux-decay model of a single generator connected to an infinite bus. This model is non-linear, and non-linearly parameterized, and the equilibria depend also non-linearly on the unknown parameters. The proposed estimator can be used, adopting a certainty equivalent approach, to make adaptive any power system stabilizer that relies on the knowledge of these parameters. The behaviour of the scheme is illustrated in two simulated case studies with the interconnection and damping assignment passivity-based controller recently proposed by the authors. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Universal resistorless current-mode filters employing CCCIIs

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 5-6 2008
Erkan Yuce
Abstract In this paper, four different-type second-order current-mode filters, employing second-generation current-controlled conveyors (CCCIIs) and two capacitors, are proposed. The first two of the presented filters can simultaneously realize high-output impedance low-pass, band-pass and high-pass responses. Also, the two filters can provide notch and all-pass filter responses with interconnection of the relevant output currents. The first developed one needs no critical active and passive element matching conditions and/or cancellation constraints. The second and third introduced ones employ only grounded capacitors. The fourth proposed filter derived from the third one uses only plus-type single output CCCIIs (CCCII+s). The fifth filter can be constructed using commercially available active devices such as AD844s along with additional resistors instead of CCCII+s of the fourth proposed filter to perform experimental test easily. All of the proposed filters have low active and passive element sensitivities. Time and frequency domain analyses are performed for the first, second and third realized filters using SPICE simulation program. Also, experimental test is achieved for the fifth filter. In this study, stability problems attributed to non-ideal gains of the CCCIIs and signal limitations of the first, second and third introduced filters due to restricted power supply voltages are investigated. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Universal current-mode filters and parasitic impedance effects on the filter performances

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 2 2008
Erkan Yuce
Abstract In this letter, two universal current-mode (CM) filters for simultaneously realizing low-pass, band-pass and high-pass characteristics are proposed. Both of the presented filters can also realize notch and all-pass responses with interconnection of the relevant output currents. They employ second-generation current-controlled conveyors (CCCIIs) and only grounded capacitors. They also have low active and passive element sensitivities along with electronically adjustable angular resonance frequency (,0) and quality factor (Q). Based on the first developed filter, the parasitic impedance effects of the conveyors on the filter performances are investigated in detail. Simulation results using SPICE simulation program are included to verify the theory. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Chemical surface passivation of 3C-SiC nanocrystals: A first-principle study

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 13 2010
A. Trejo
Abstract The effect of the chemical surface passivation, with hydrogen atoms, on the energy band gap of porous cubic silicon carbide (PSiC) was investigated. The pores are modeled by means of the supercell technique, in which columns of Si and/or C atoms are removed along the [001] direction. Within this supercell model, morphology effects can be analyzed in detail. The electronic band structure is performed using the density functional theory based on the generalized gradient approximation. Two types of pores are studied: C-rich and Si-rich pores surface. The enlargement of energy band gap is greater in the C-rich than Si-rich pores surface. This supercell model emphasizes the interconnection between 3C-SiC nanocrystals, delocalizing the electronic states. However, the results show a clear quantum confinement signature, which is contrasted with that of nanowire systems. The calculation shows a significant response to changes in surface passivation with hydrogen. The chemical tuning of the band gap opens the possibility plenty applications in nanotechnology. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem 110:2455,2461, 2010 [source]

Stabilization of an underactuated bottom-heavy airship via interconnection and damping assignment

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 18 2007
Zili Cai
Abstract This paper focuses on feedback stabilization of a neutrally buoyant and bottom-heavy airship actuated by only five independent controls (with the rolling motion underactuated). The airship is modelled as an eudipleural submerged rigid body whose dynamics is formulated as a Hamiltonian system with respect to a Lie,Poisson structure. By exploiting the geometrical structure and using the so-called interconnection and damping assignment (IDA) passivity-based methodology for port-controlled Hamiltonian systems, state feedback control laws asymptotically stabilizing two typical motions are designed via La Salle invariance principle and Chetaev instability theorem. Simulation results verify the control laws. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Further constructive results on interconnection and damping assignment control of mechanical systems: the Acrobot example

A robust integrated controller/diagnosis aircraft application

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 12 2005
Andrés Marcos
Abstract In this paper, an application of the robust integrated control/diagnosis approach using ,, -optimization techniques to the nonlinear longitudinal dynamics of a Boeing 747-100/200 aircraft is presented. The integrated approach allows to address directly the trade-off between the conflicting controller and fault diagnosis objectives. The integrated design formulation (interconnection and weight selection) is defined using five LTI plants obtained through out the Up-and-Away flight envelope. Linear and nonlinear closed-loop time simulations are carried out under a realistic turbulence and noise environment. A comparison drawn with the non-integrated design of a controller and a diagnosis filter with the same objectives shows that the integrated case results in similar diagnosis characteristics but improved fault tolerant performance and ease of design. Copyright © 2005 John Wiley & Sons, Ltd. [source]

A dissipative dynamical systems approach to stability analysis of time delay systems

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 1 2005
VijaySekhar Chellaboina
Abstract In this paper the concepts of dissipativity and the exponential dissipativity are used to provide sufficient conditions for guaranteeing asymptotic stability of a time delay dynamical system. Specifically, representing a time delay dynamical system as a negative feedback interconnection of a finite-dimensional linear dynamical system and an infinite-dimensional time delay operator, we show that the time delay operator is dissipative with respect to a quadratic supply rate and with a storage functional involving an integral term identical to the integral term appearing in standard Lyapunov,Krasovskii functionals. Finally, using stability of feedback interconnection results for dissipative systems, we develop sufficient conditions for asymptotic stability of time delay dynamical systems. The overall approach provides a dissipativity theoretic interpretation of Lyapunov,Krasovskii functionals for asymptotically stable dynamical systems with arbitrary time delay. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Co-ordinated control design of generator excitation and SVC for transient stability and voltage regulation enhancement of multi-machine power systems

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 9-10 2004
L. Cong
Abstract This paper presents a co-ordinated control scheme for generator excitation and a static var compensator (SVC) to achieve transient stability, adequate damping and voltage regulation enhancement of multimachine power systems. By using the feedback linearization technique, the nonlinearities of the generator and the SVC model are cancelled. With the help of robust control theory, the interconnection between controllers, the variation of system structure and the parameter uncertainties are taken into consideration in the controller design. Only local measurements are required. Simulation results obtained from a three-machine, one-SVC example system show that the proposed controllers can provide good stability, voltage control and damping over a wide range of operating conditions. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Optimal hold functions for MDCS sampled-data problems

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 12 2003
Leonid Mirkin
Abstract In this paper the H2 and H, sampled-data problems with mixed discrete/continuous specifications (MDCS) are considered. The hold function is not fixed a priory but rather is the design parameter. The (sub)optimal controller obtained is of the form of a serial interconnection of a (sub)optimal digital controller and a (sub)optimal hold function. It is demonstrated that the incorporation of the hold function into the sampled-data design with MDCS extends considerably the possibility to reach a required trade-off between discrete and continuous specifications in comparison with designs with a fixed hold function. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Balancing work and welfare: activation and flexicurity policies in The Netherlands, 1980,2000

INTERNATIONAL JOURNAL OF SOCIAL WELFARE, Issue 1 2004
Wim Van Oorschot
As a result of the flexibilisation of labour and the trend towards the ,activating welfare state', social policies show an increasing interconnection of work and welfare issues. The Netherlands is no exception. It is generally believed that the Dutch welfare state is successfully activating its unemployed labour potential (often referred to as the ,Dutch Miracle'), and that flexible and part-time work is protected by adequate ,flexicurity'. This article critically reviews Dutch activation and flexicurity policies. It concludes that there is still more unemployment than the miracle-story suggests; that important target groups of activation policies have not profited from ,the miracle'; that part-time workers have sufficient social protection but that social security for flex-workers still needs major improvements, despite favourable adjustments of labour law. [source]

An innovative method to obtain porous PLLA scaffolds with highly spherical and interconnected pores

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2008
Cédryck Vaquette
Abstract Scaffolding is an essential issue in tissue engineering and scaffolds should answer certain essential criteria: biocompatibility, high porosity, and important pore interconnectivity to facilitate cell migration and fluid diffusion. In this work, a modified solvent casting-particulate leaching out method is presented to produce scaffolds with spherical and interconnected pores. Sugar particles (200,300 ,m and 300,500 ,m) were poured through a horizontal Meker burner flame and collected below the flame. While crossing the high temperature zone, the particles melted and adopted a spherical shape. Spherical particles were compressed in plastic mold. Then, poly- L -lactic acid solution was cast in the sugar assembly. After solvent evaporation, the sugar was removed by immersing the structure into distilled water for 3 days. The obtained scaffolds presented highly spherical interconnected pores, with interconnection pathways from 10 to 100 ,m. Pore interconnection was obtained without any additional step. Compression tests were carried out to evaluate the scaffold mechanical performances. Moreover, rabbit bone marrow mesenchymal stem cells were found to adhere and to proliferate in vitro in the scaffold over 21 days. This technique produced scaffold with highly spherical and interconnected pores without the use of additional organic solvents to leach out the porogen. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source]