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Open access

Christopher Chiu and Zenon Chaczko

Abstract

The enhancement of surgical simulation tools is an important research study, to assist in the assessment and feedback of medical training practice. In this research, the Spring Tensor Model (STEM) has been used for laparoscopic end-effector navigation through obstacles and high-risk areas. The modelling of the surgical trainer as part of the laparoscopic simulator seeks to emulate the physical environment as a virtualised representation in the integrated infrastructure. Combining sensor network framework paradigms to a surgical knowledge-based construct demonstrates how STEMcan enhance medical practice. The architectural hybridisation of the training framework has enabled the adaptation of STEM modelling techniques for a simulated laparoscopic training methodology. The primary benefit of the architecture is that this integration strategy has resulted in a seamless transition of the heuristic framework to be applied to surgical training.

Open access

Rafał Rytel-Andrianik

Abstract

The output of the quadrature demodulator is generally regarded as a complex signal that is circular if only the demodulator is well balanced. In the paper we analyze properties of quadrature demodulators, particularly digital one, and show that the output is noncircular also if the input signal is nonstationary. Then we find sources of this noncircularity and show that they stem from transients of the low-pass demodulator filter. This is quite important because nonstationary inputs are quite typical in radar where power of echoes depends strongly on range. In the first sections we also review complex random signals and properties of circularity and properness.

Open access

M. Najmie, K. Khalid, A. Sidek and M. Jusoh

Density and Ultrasonic Characterization of Oil Palm Trunk Infected by Ganoderma Boninense Disease

Oil palm trunks infected by Ganoderma boninense disease have been studied using density and ultrasonic characterizations. The ultrasonic characterizations have been performed using a commercial ultrasonic instrument at the frequency of 54 kHz. The measurements have been done in 3 zones: inner zone, central zone and peripheral zone. It was found that the stem density of the oil palm infected by Ganoderma boninense disease was reduced by 50% in comparison to the original healthy trunk. From this effect the velocity of the ultrasonic wave propagated through the Longitudinal, Radial, and Tangential directions is lower for the trunk infected by Ganoderma boninense disease compared to a healthy trunk. For the 10 cm thickness of samples, the ultrasonic velocity for all transit directions was in range of 260 - 750 ms-1 for the infected sample, whereas for healthy samples was in the range of 460 - 900 ms-1. These results are very useful for the detection of the area which has been affected by the disease.

Open access

Tomáš Stejskal, Tatiana Kelemenová, Miroslav Dovica, Peter Demeč and Miroslav Štofa

Abstract

The input of this paper lies in displaying possibilities how to determine the condition of a coordinate measuring machine (CMM) based on a large number of repeated measurements. The number of repeated measurements exceeds common requirements for determining positioning accuracy. The total offset in the accuracy of spatial positioning consists of partial inaccuracies of individual axes. 6 basic errors may be defined at each axis. In a triaxial set, that translates into 18 errors, to which an offset from the perpendicularity between the axial pairs must be added. Therefore, the combined number of errors in a single position is 21. These errors are systemic and stem from the machine’s geometry. In addition, there are accidental errors to account for as well. Accidental errors can be attributed to vibrations, mass inertness, passive resistance, and in part to fluctuations in temperature. A peculiar set of systemic errors are time-varying errors. The nature of those errors may be reversible, for instance if they result from influence of temperature or elastic deformation. They can be also irreversible, for example as a result of wear and tear or line clogging, due to loosened connection or permanent deformation of a part post collision. A demonstration of thermal equalizing of the machine’s parts may also be observed in case of failure to adhere to a sufficient time interval from the moment the air-conditioning is turned on. Repeated measurements done on a selected axis with linear interferometer can provide complex information on the CMM condition and also on the machine’s interaction with the given technical environment.

Open access

Slobodan Tabakovic, Milan Zeljkovic and Zoran Milojevic

References [1] Pawlikowski, M., Skalski, K., Haraburda, M. (2003). Process of hip joint prosthesis design including bone remodeling phenomenon. Computers & Structures, 81 (8-11), 887-893. [2] Ramos, A., Completo, A., Relvas, C., Simoes, J.A. (2012). Design process of a novel cemented hip femoral stem concept. Materials & Design, 33, 313-321. [3] Garellick, G., Karrbolm, J., Rogmark, C., Herberts, P. (2011). Annual Report 2010. Swedish Hip Arthroplasty Register. [4] International Organisation for

Open access

Corina Rotar and Laszlo Barna Iantovics

, p. 2435-2437. [10] Weber L., Applications of genetic algorithms in molecular diversity, Current Opinion in Chemical Biology 2.3, 1998, p. 381-385. [11] Arnold F. H., Design by directed evolution, Accounts of chemical research 31.3, 1998, p. 125-131. [12] Cadwell R. C., and Gerald F. J., Randomization of genes by PCR mutagenesis, Genome research 2.1, 1992, p. 28-33. [13] Stemmer W. PC., Rapid evolution of a protein in vitro by DNA shuffling, Nature 370.6488, 1994, p. 389-391. [14] Gartner Z. J., Evolutionary approaches for the

Open access

Fruzsina Horváth and László Pokorádi

Abstract

During technical education it is a very difficult yet essential task to develop the good logical engineering thinking of students or pupils. One main part of this thinking is the determination of the optimal set of required input parameters for the calculation task mentioned above. The LogTreeMM (Logical Tree of Mathematical Modelling) method can help to solve this task. The aim of this paper is to show modification of the LogTreeMM method to determine the required parameters of a mathematical model by a simple case study.

Open access

Maurice Dawson and Pedro Manuel Taveras Nuñez

Abstract

Many developed countries are placing resources to combat the growing threats in cyberspace, and emerging nations are no different. Since 2016, the Dominican Republic is undergoing massive changes within the current government to prioritize cybersecurity through laws, policies, and doctrine. This initiative is causing politicians, industry, and even government entities such as the national police to start the journey to begin to fully understand what are the issues in cybersecurity as they apply to the nation. It is essential that the security challenges and problems identified are addressed through a process of discovery while mitigating risks. This paper is to present those challenges and offer solutions that can be used to achieve an acceptable level of cyber risk.

Open access

Aurél Benárd

Abstract

Reykjavík’s largest church, Hallgrímskirkja has become a symbol and an important part of Icelandic national identity. This edifice result of conscious planning process with its location and form reinforce its national significance. Its impact derives from several elements. Buildings symbolizing the identity of communities are usually quite conservative in form. Hallgrímskirkja, however, has distinct individual features that stem from architect Guðjón Samúelsson’s aspiration to express the nation’s identity in a specific architectural form.

Open access

Arkadiusz Woźniak

Abstract

The evaluation of the impact of contamination in breathing air intended for hyperbaric purposes is essential both for practical and theoretical reasons. The quality of breathing air and the breathing mixes obtained on its basis is of crucial importance with regard to divers’ safety in the course of underwater works. The existing contaminants, as well as substandard quality gases have an adverse impact on divers’ health and life, both in terms of the physiological impact on the body, and fire hazards in hyperbaric complexes. In the process of breathing air production we deal with a few sources of potential contaminants stemming from technical measures. The human body is also responsible for the release of contaminants in hyperbaric conditions. The article presents the above issues and provides insight into existing threats.