Showing papers by "Technological Educational Institute of Western Macedonia published in 2010"

New modified Runge-Kutta-Nyström methods for the numerical integration of the Schrödinger equation

Abstract: In this work we construct new Runge-Kutta-Nystrom methods especially designed to integrate exactly the test equation y^''=-w^2y. We modify two existing methods: the Runge-Kutta-Nystrom methods of fifth and sixth order. We apply the new methods to the computation of the eigenvalues of the Schrodinger equation with different potentials such as the harmonic oscillator, the doubly anharmonic oscillator and the exponential potential.

Food safety management systems (FSMS) in the dairy industry: A review

Abstract: Food safety management systems in the industry have been designed and established over the last four decades with several revisions. The dairy industry soon realised the need for proactive procedures hence implementing HACCP (Hazard Analysis and Critical Control Points) for ensuring that safe dairy products would reach the consumers. This article reviews the food safety management systems as well as the relevant EC Regulations that are currently implemented by the dairy industry. The need for rigorous controls in the dairy industry is also highlighted.

Rapid computation of eddy current signals from narrow cracks

Abstract: An existing boundary element method model for eddy current inspection of ideal or narrow cracks is revised. Using some lately devised concepts on efficiently and rapidly simulating canonical eddy current geometries, we show how this model can be made easier to implement and faster to calculate. The approach is largely based on a novel method for rapidly calculating the Green's function and reducing the matrix fill-time, and also on a similar method for rapidly computing the incident electric field. As a result, the model has been made an order of magnitude faster than the existing one without sacrificing accuracy. We pay attention to numerical analysis details and analyze issues that so far have not been clarified. The validity of our approach is also verified by the experiment. Although we have tested the model against published data, we have also produced our own precision measurements for surface and through-the-thickness slots in plates with the coils performing scans along and across the slots at various frequencies.

Solution casting versus melt compounding: effect of fabrication route on the structure and thermal behavior of poly(l-lactic acid) clay nanocomposites

Abstract: Poly(l-lactic acid) (PLLA) nanocomposites containing various loadings of organo-modified montmorillonite were prepared via twin screw extrusion and solution casting in order to investigate the effect of processing route on the structure and the thermal properties of the fabricated nanohybrid materials. X-ray diffraction (XRD) testing indicated that a better dispersion of the modified inorganic filler can be achieved by solution intercalation. The interlayer distance of the mineral, and thus the type and structure of the nanohybrid formed, was found to be affected by the polymer content only in the case of the nanocomposites produced by the solution casting method. Thermogravimetric analysis (TGA) revealed that the hybrids prepared by melt compounding displayed increased thermal stability. Differential scanning calorimetry (DSC) showed that the fabrication route influences the crystallization process of the polymer.

An ANN Approach on the Optimization of the Cutting Parameters During CNC Plasma-Arc Cutting

Abstract: The objective of the present study is to develop an Artificial Neural Network (ANN) in order to predict the bevel angle (response variable) during CNC plasma-arc cutting of St37 mild steel plates. The four (4) input parameters (plate thickness, cutting speed, arc ampere, and torch standoff distance) of the ANN was selected following the results (relative importance) of the Analysis Of Variance (ANOVA) performed based on seven (7) factors (plate thickness, cutting speed, arc ampere, arc voltage, air pressure, pierce height, and torch standoff distance) in a previous study. A multi-parameter optimization was carried out using the robust design. An L18 (21 × 37 ) Taguchi orthogonal array experiment was conducted and the right bevel angle was measured, aiming at the investigation of the influence of plasma-arc cut process parameters on right side bevel angle of St37 mild steel cut surface. The selection of quality characteristics, material, plate thickness and other process parameter levels and experimental limits was based on the experience and current needs of the Greek machining industry. A feed-forward backpropagation (FFBP) neural network was fitted on the experimental data. The results show that accurate predictions of the bevel angle can be achieved inside the experimental region, through the trained FFBP-ANN. The developed ANN model could be further used for the optimization of the cutting parameters during CNC plasma-arc cutting.Copyright © 2010 by ASME

Thermodynamic characterization of poly(2,2,3,3,3‐pentafluoropropyl methacrylate)

Abstract: The thermodynamic characterization of a fluorinated methacrylic homopolymer was conducted by means of inverse gas chromatography (IGC), at infinite dilution. The homopolymer under study, poly(2,2,3,3,3-pentafluoropropyl methacrylate) (PPFPMA), was synthesized via a free radical polymerization reaction and was characterized by the employment of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and size exclusion chromatography (SEC) techniques. The specific retention volume of 15 solvents, used as probes, was used for the assessment of the Flory-Huggins interaction parameter, the weight fraction activity coefficient, the molar heat, energy and entropy of sorption, the partial heat of mixing of the probes, as well as the solubility parameter of the polymer. The results demonstrate that PPFPMA is insoluble in most organic solvents even at increased temperatures, with the exception of solvents like 2-Butanone.

Choice of Money Transfer Methods in the Case of Albanian Immigrants in Greece

Abstract: This paper investigates the choice of the method that immigrants use for the transfer of savings to their home country. The paper examines the example of Albanian immigrants in Greece using a sample of permanent and seasonal immigrants. Three methods were proposed to the immigrants: the banking network, money transfer companies and hand carried transfer by their or a relative’s return in Albania. Cost and quickness of transfer were considered as a parameter for the choice. The paper finds that despite the growth of remittances through the official network and the growth of this network in Albania, immigrants prefer to send money through the parallel market by their return or a relative’s in Albania. Within the official market, permanent immigrants are more likely to use the banking network while seasonal immigrants prefer to use the money transfer companies’ network.

A survey on reputation-based cooperation enforcement schemes in wireless ad hoc networks

Abstract: Mobile ad hoc networks rely on node cooperation to perform and support basic functions like packet forwarding, routing and network management. In general, nodes' misbehaviour can significantly degrade the performance of the network. Cooperation enforcement schemes are seen as a lightweight alternative to conventional security techniques, providing a “softer” security layer to protect basic networking operations. The aim of this paper is to survey representative cooperation enforcement schemes exploiting a reputation system proposed in related research literature. Their distinct features are analyzed and their relative merits and weaknesses are discussed.

Neutral current neutrino–98Mo reaction cross sections at low and intermediate energies

Abstract: Inelastic neutrino–nucleus reaction cross sections at low and intermediate neutrino energies are studied. The required many-body nuclear wavefunctions are calculated in the context of a quasi-particle random phase approximation that uses realistic two-body forces. The results presented here refer to the differential, integrated and total cross sections of the neutral-current-induced reaction of νe with the 98Mo nucleus. Exploiting the obtained results, we investigate the response of this isotope as a supernova neutrino detector, assuming a two-parameter Fermi–Dirac distribution for the supernova neutrino energy spectra.

Development of a collaborative vehicle collision avoidance system

Abstract: Advanced systems for driver assistance in combination with new preventive safety systems offer great potential for collision avoidance, reducing accident severity and increasing occupant protection. This paper presents the development and evaluation of a system targeting to vehicle collision avoidance in emergency situations. The proposed system provides the nearby vehicles with information about possible accident involvement. The main feature of the proposed system is the wireless communication among vehicles during normal driving in case of emergency situations. The wireless communication is originated by a vehicle in emergency state while the vehicles in range get benefit of the transmitted information. The wireless communication packet is comprised of the type of the vehicle, which originates the transmission, the description of the current situation, and the geographical position of the vehicle which is provided by a Geographical Positioning System (GPS) module. The critical issues and other technical challenges in developing these systems will be explored.

Endogenous rural development: evidence from a typical greek region

Abstract: The current financial and institutional crisis in Greece has brought far-reaching consequences for the whole economy including rural development. Nevertheless, farmers and rural residents can profit from the opportunities and synergies offered by other activi-ties that are complementary and alternative to agriculture and thus they can liberate themselves from the unique role of producers. Rural residents, farmers and entrepreneurs in less favored Greek areas play an essential role in the valorization of endogenous re-sources of the area where they are operating. This paper aims to examine the willingness of the residents of a typical Greek region to accept and support a local factor such as a union of agricultural cooperatives and to reveal the foremost reasons thereof. To that ef-fect, a survey of 500 rural residents was performed using both summary statistics and multivariate analysis while a categorical re-gression analysis was applied to determine the relation between the respondents' socioeconomic characteristics and their willingness to adopt the endogenous potential. The survey findings indicate the success of the Union investment project and the confidence of the local community in a local cooperative organization. Thus, this local business initiative can significantly reduce the impact of the economic crisis on Greek rural residents by generating additional income from indigenous resources.

Medical Rapid Prototyping and Manufacturing: Status and Outlook

Abstract: Rapid Prototyping (RP) has been considered, over the last decades, as a highly promising technology for reducing product development time and cost, as well as for addressing the need for customization and faster response to the market needs. Nowadays this technology is also used widely in medical applications (Medical Rapid Prototyping – MRP), supporting diagnosis and treatment in Neurosurgery, Orthopedic and Dental-Cranio-Maxillo-Facial surgery as well as in Tissue Engineering. The scan data that are usually obtained by Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) are used to build a 3D CAD model of the patient’s pathological region. The 3D model is used to construct the real size prototype using one of the existing RP processes. This assists surgeons in gaining a detailed insight of the problem, making the diagnosis and treatment easier and more reliable. This study presents the current benefits and barriers of Rapid Prototyping and Manufacturing methods and applications in the field of medicine. Most of the recent state-of-art developments and case studies of MRP are presented. Their limitations are discussed along with the challenges to be addressed in the future.Copyright © 2010 by ASME

Regression Analysis about Humidity Elimination from Diesel Fuel Via Bioorganic Compounds to Increase Antifouling Action

Abstract: In this paper we try to export a regression equation which describes the variation of humidity of Diesel fuel with time. A hydrophilic polymer is used to eliminate humidity from diesel fuel and the regression analysis shows that the maximum decrease of humidity in an hour it is of about ˜ 35%.

Efficient Service Task Assignment in Grid Computing Environments

Abstract: Grids facilitate the employment of various nodes comprising supercomputers, storage elements and databases that are distributed for resolving computational demanding problems in many disciplines of science and commerce (Foster, 2001). To utilize Grids effectively, an efficient allocation algorithm is needed to assign service tasks to Grid resources. Thus, assuming that a user wishes to perform a specific service task, which can be served by various candidate Grid nodes (CGNs), a problem that should be addressed is the assignment of the requested service task to the most appropriate Grid node. In this paper, the pertinent problem is called Service Task Allocation (STA).

Prediction of surface roughness in turning using orthogonal matrix experiment and neural networks

Abstract: A neural network modeling approach is presented for the prediction of surface texture parameters during turning of a copper alloy (GC-CuSn12). Test specimens in the form of near-to-net-shape bars and a titanium nitride coated cemented carbide (T30) cutting tool were used. The independent variables considered were the cutting speed, feed rate, cutting depth and tool nose radius. The corresponding surface texture parameters that have been studied are the Ra, Rq, and Rt. A feed forward back propagation neural network was developed using experimental data which were conducted on a CNC lathe according to the principles of Taguchi design of experiments method. It was found that NN approach can be applied in an easy way on designed experiments and predictions can be achieved, fast and quite accurate. The developed NN is constrained by the experimental region in which the designed experiment is conducted. Thus, it is very important to select parameters’ levels as well as the limits of the experimental region and the structure of the orthogonal experiment. This methodology could be easily applied to different materials and initial conditions for optimization of other manufacturing processes.

Automatic Generation of Massively Parallel Hardware from Control-Intensive Sequential Programs

Abstract: High-level synthesis has been envisaged as a suitable methodology to design and deliver on time, at least large parts of today’s complex IC systems. This paper describes a unified and integrated HLS framework, to automatically produce custom and massively-parallel hardware, including its memory and system interfaces from high-level sequential program code. Using compiler-generators and logic programming techniques, provably-correct hardware compilation flow is achieved. The utilized hardware optimization inference engine is driven by a set of resource constraints, which limit to a certain boundary the number of available hardware operators to function in parallel during each control step. This optimization reduces drastically the number of different control steps (states) of the implemented application. The hardware compilation runs are completed in orders-of-magnitude less time than that which would be needed by even very experienced HDL designers to implement the same applications in RTL code. Implementation results from synthesis of a number of control-dominated, linear and repetitive, applications including a MPEG video compression engine with up to a few hundred states, are presented. In all cases the HLS framework delivers quickly provably-correct, implementable RTL code and the optimized schedule is reduced at up to 30% in comparison with the initial schedule.

Towards Efficient Trust Aware E-Marketplace Frameworks

Abstract: INTRODUCTION In the liberalised and deregulated e-marketplace some key factors for service providers’ success are the following. First, the efficiency with which services will be developed. Second, the quality level, in relation with the corresponding cost, of new services. Third, service providers’ reliability with respect to service provisioning. Fourth, the efficiency with which the services will be operated (controlled, maintained, administered, etc.). The aim of this paper is, in accordance with efficient service operation objectives, to propose enhancements to the sophistication of the negotiation functionality that can be offered by e-commerce systems in open competitive communications environments.

European Culture or a Europe of Cultures? An assessment of European Union policies on audiovisual media and culture, and their implementation in Greece

Abstract: The purpose of this study is to present a documented and critically-oriented subject that promotes the exploration of the terms for shaping and developing European policy on audiovisual media and culture, highlighting the creation of a European cultural area in which Greece is an active participant. The vital questions that are analysed and explored are the following:  What is the European policy on culture and audiovisual media?  Which programmes, measures and actions has the EU developed in the fields of culture and audiovisual media?  What are the results of this specific European policy and the consequences arising from its implementation in Greece?

A personalized audio server using MPEG-7 and MPEG-21 standards

Abstract: This paper presents a semantic model which delivers personalized audio information. The personalization process is automated and decentralized. The metadata which support personalization are separated in two categories: the metadata describing user preferences stored at each user and the resource adaptation metadata stored at the server. The multimedia models MPEG-21 and MPEG-7 are used to describe metadata information. The Web Ontology Language (OWL) language is used to produce and manipulate the relative ontological descriptions.

Comparison Between Two-Shaft Simple and Single-Shaft Recuperated Brayton Cycles Using Different Types of Gaseous Fuels

Abstract: Geopolitical issues give rise to problems in the smooth and continuous flow of oil and natural gas from the production countries to the consumers’ development countries. In addition, severe environmental issues such as greenhouse gas emissions, eventually guide the consumers to fuels more suitable to the present situation. Alternative fuels such as biogas and coal gas have recently become more attractive because of their benefits, especially for electricity generation. On the other hand, the use of relatively low heating value fuels has a significant effect to the performance parameters of gas turbines. In this paper, the impact of using four fuels with different heating value in the gas turbine performance is simulated. Based on the high efficiency and commercialization criteria, two types of engines are chosen to be simulated: two-shaft simple and single-shaft recuperated cycle gas turbines. The heating values of the four gases investigated, correspond to natural gas and to a series of three gases with gradually lower heating values than that of natural gas. The main conclusions drawn from this design point (DP) and off-design (OD) analysis is that, for a given TET, efficiency increases for both engines when gases with low heating value are used. On the contrary, when power output is kept constant, the use of gases with low heating value will result in a decrease of thermal efficiency. A number of parametric studies are carried out and the effect of operating parameters on performance is assessed. The analysis is performed with customized software, which has been developed for this purpose.© 2010 ASME

Synthesis of provably-correct hardware with options

Abstract: This paper describes a formal high-level synthesis framework that is used to automatically generate provably-correct hardware from high-level, behavioural, algorithmic program code, with options of memory use and target FSM+datapath configurations. The correctness of the generated hardware accelerators is ensured by the use of compiler-generator and logic programming techniques. Internal, on-chip or external, shared memory use, as well as generation of massively-parallel or classic FSM+datapath can be selected via the use of compilation options. The required I/O and memory interfaces and communication handshake protocols are automatically generated by the hardware compiler. The generated hardware states are optimized with the use of the PARCS (resource-constrained) algorithm. The suitability of the presented design framework is proven with a number of test benchmarks including a MPEG video compression design.

Modified Floyd-Warshall algorithm for risk arbitrage

Abstract: Traditionally risk arbitrage is the simultaneous purchase of stock in a company being acquired and the sale of stock of the acquirer. Modern risk arbitrage focuses on capturing the spreads between the market value of an announced takeover target and the eventual price at which the acquirer will buy the target's shares. Here we look at the concept of arbitrage, how market makers utilize "true arbitrage," and, finally, how retail investors can take advantage of arbitrage opportunities.