Search results

Filters

  • Journals
  • Keywords
  • Date

Search results

Number of results: 304
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

Programming frameworks [1] are application generators with the following components: library of software modules (building blocks out of which the system is constructed), a method for designing new modules that can be appended to the above mentioned library, a pattern according to which ready modules can be assembled into a complete system jointly exerting control over it and realizing the task at hand. The presented transition function based formalism can be applied to specifying programming frameworks for robot controllers executing very diverse tasks. The paper deals with systems consisting of multiple embodied agents, influencing the environment through effectors, gathering information from the environment through sensors and communicating with other agents through communication channels. The presented code patterns pertain to behavioural agents. The formalism was instrumental in the design of MRROC++ robot programming framework, which has been used for producing controllers of single and two manipulator systems performing diverse tasks. The formalism introduces rigor into the discussion of the structure of embodied agent controllers. It is used as the means for the specification of the functions of the components of the control system and the structure of the communication links between them. This structures the implementation of a programming framework, and that in turn makes the coding of specific controllers much easier, both from the point of view of dealing with the hardware configuration of the system and the specific task that has to be executed.

Go to article

Authors and Affiliations

C. Zieliński
Download PDF Download RIS Download Bibtex

Abstract

The steel pipe umbrella is a widely used technology when tunnelling in weak soils in order to create pre-support ahead of the tunnel face. The design of steel pipes is frequently done through simplified analytical approaches which are easy to apply but require proper assessment of the loads acting on the pipe. To provide information on this key design aspect, the results of the comparison between a three-dimensional numerical model developed with the code FLAC 3D and an analytical model based on the approach of a beam on yielding supports is presented and discussed. The comparison refers to a shallow tunnel with an overburden of three times its diameter for two different types of weak rock masses. The obtained results provide suggestions about the load that has to be applied in the analytical model for the design phase.

Go to article

Authors and Affiliations

D. Peila
C. Marchino
C. Todaro
A. Luciani
Download PDF Download RIS Download Bibtex

Abstract

This Article investigates how the European Court of Human Rights becomes competent to make decisions in cases concerning (or taking roots in) “historical situations” preceding the ratifi cation of the European Convention by a given Member State or even the enactment of the Convention. “Historical situations” refer to events that occurred in the period of Second World War or shortly thereafter. In all such cases, the preliminary question arises whether the Court is competent temporally (ratione temporis) to deal with the application. This group of cases concerned usually allegations touching upon the right to life and the right to property. The Court had to decide if the allegation in question related to a temporally closed event (making the Court not competent) or rather to a continuous violation (where the Court could adjudicate). A specifi c set of legal questions arose vis-à-vis the right to life, fi rst of all that of the autonomy of the procedural obligation to conduct an effi cient investigation. The Strasbourg case law did not provide a clear answer. However, following two crucial judgements rendered by the Grand Chamber, the Court has established an interesting legal framework. Article analyses also two other situations having a historical dimension: bringing to justice those accused of war crimes or other crimes under international law (in light of the alleged confl ict with the principle of nullum crimes sine lege) and pursuing authors of pro-Nazi statements or speech denying the reality of Nazi atrocities.
Go to article

Authors and Affiliations

Ireneusz C. Kamiński
Download PDF Download RIS Download Bibtex

Abstract

This paper presents a simplified modeling, simulation and Experimental analysis of permanent magnet brushless dc motors (PMBLDC) for sensorless operation. This model provides a mechanism for monitoring and controlling of voltage, current, Speer and torque. The sensorless scheme employs direct back emf based zero crossing detection for controlling the dynamic characteristics.

Go to article

Authors and Affiliations

E. Kaliappan
C. Chellamuthu
Download PDF Download RIS Download Bibtex

Abstract

The most important feature of bells is their sound. Its clarity and beauty depend, first of all, on the bell’s geometry - particularly the shape

of its profile, but also on the quality of alloy used to its cast. Hence, if the melting and pouring parameters could influence the alloy’s

properties, what influence they would have on the frequencies of bell’s tone. In the article authors present their own approaches to find

answers on that and more questions.

Go to article

Authors and Affiliations

D. Bartocha
C. Baron
Download PDF Download RIS Download Bibtex

Abstract

An analytical expression for the standard deviation of Total Harmonic Distortion (THD) estimation is derived. It applies to the case where the estimator uses sine fitting. It is shown that, in common circumstances, it is inversely proportional to the actual value of THD, the signal-to-noise ratio and the square root of the number of samples. The proposed expression is validated both with numerical simulations and an experimental setup using a Monte Carlo procedure.

Go to article

Authors and Affiliations

Francisco C. Alegria
Download PDF Download RIS Download Bibtex

Abstract

This paper is an overview of the application potential and design challenges of micro air vehicles (MAVs), defined as small enough to be practical for a single-person transport and use. Four types of MAVs are considered: 1) fixed-wing, 2) rotarywing, 3) ornithopters (bird-like flapping) and 4) entomopters (insect-like flapping). In particular, advantages of a propeller-driven delta wing configuration for type 1 are discussed. Some detail is also given for type 4, the least understood of the four, including a new concept of manoeuvre control for such MAVs. The paper concludes with a brief prognostic of the future of each MAV type.

Go to article

Authors and Affiliations

C. Galiński
R. Żbikowski
Download PDF Download RIS Download Bibtex

Abstract

The paper presents magnetic fluid as an excellent material platform for producing more complex magnetic drug delivery systems. In addition, the paper discusses the nanoparticle morphological (electron microscopy) and structural (X-ray diffraction) characterizations. M ossbauer spectroscopy and photoacoustic spectroscopy are revisited as key tools in the characterization of the magnetic core and diamagnetic shell of the magnetic nanoparticle, respectively.

Go to article

Authors and Affiliations

P.C. Morais
Download PDF Download RIS Download Bibtex

Abstract

This paper proposes a practical tuning of closed loops with model based predictive control. The data assumed to be known from the process is the result of the bump test commonly applied in industry and known in engineering as step response data. A simplified context is assumed such that no prior know-how is required from the plant operator. The relevance of this assumption is very realistic in the context of first time users, both for industrial operators and as educational competence of first hand student training. A first order plus dead time is approximated and the controller parameters immediately follow by heuristic rules. Analysis has been performed in simulation on representative dynamics with guidelines for the various types of processes. Three single-input-single-output experimental setups have been used with no expert users available in different locations – both educational and industrial – these setups are representative for practical cases: a variable time delay dominant system, a non-minimum phase system and an open loop unstable system. Furthermore, in a multivariable control context, a train of separation columns has been tested for control in simulation, followed by experimental tests on a laboratory system with similar dynamics, i.e. a sextuple coupled water tank system. The results indicate the proposed methodology is suitable for hands-on tuning of predictive control loops with some limitations on performance and multivariable process control.

Go to article

Authors and Affiliations

C. Ionescu
D. Copot

This page uses 'cookies'. Learn more