Partizan Malkaj | Politechnic University of Tirana (original) (raw)

Papers by Partizan Malkaj

In this paper we perform a quality control over an chaotic masking encryption scheme. We simulate... more In this paper we perform a quality control over an chaotic masking encryption scheme. We simulate a nonlinear system based on Chua's chaotic oscillator. Simulations were carried out using Multisim, which is widely accepted as the circuit simulation software that provides for an interface adequately close to real implementation. In order the circuit to be used in chaotic encryption schemes we have implemented a master slave chaotic synchronization scheme. We investigate the robustness of the simulation with respect to the resistance of the line which connect the two systems. For our results we have figure out that the synchronization could be achieved if the line has a total resistance below 3.5kΩ.

Abstract: In this paper we study the meaning and importance of Lyapunov exponents through methods... more Abstract: In this paper we study the meaning and importance of Lyapunov exponents through methods of analysis of experimental data applied in physics, and especially in chaotic circuits. The Lyapunov exponents play a very important role in detecting chaos, which occurs in many areas of science and technology. So, the question belongs to the theory of chaotic dynamical systems and generally all dynamical systems, which should analyzed correctly and accurately to obtain the correct conclusions regards Lyapunov exponents. The purpose of the study is to find the Lyapunov exponents for various dynamical systems and the explanation of the results for the dynamic behavior of each system. We also present applications science where Lyapunov exponents play an important role in explaining the main algorithms to calculate these exponents under different implementation and different computer packages. Index Terms: chaos, nonlinear sience, lyapunov exponents

Abstract: In this paper is presented a new design for Young Interferometer (YI) biosensor and the... more Abstract: In this paper is presented a new design for Young Interferometer (YI) biosensor and the analysis of output power of a MMI waveguide that will be used in it. The waveguides are simulated with OptiBPM software, which is a Waveguide Optics Modeling software from Optiwave Coorporation. Output power and excess loss is analysed for 15 and 110 planar MMI waveguides for different wavelengths with TE and TM polarization. It is demonstrated that output power decreases exponentially with the increase of the wavelength for both polarizations. The evaluation of the excess loss shows that it is higher for a TM polarized field for all the wavelengths and periodicities considered. Power imbalance seems to have small values suggesting the use of MMI waveguides as good power splitters. A comparison of the excess loss between 15 and 110 MMI waveguides shows that it remains almost the same for both polarizations for the optimum wavelength ( = 647 nm).

An analysis of the factors that influence the measurement errors of the four channel Young interf... more An analysis of the factors that influence the measurement errors of the four channel Young interferometer (YI) immunosensor are discussed and some possible techniques to reduce them are tested. Through the use of Matlab software, the effect of CCD camera resolution, Hanning window, and noise averaging on phase error (PE) and cross-talk (CT) is tested. It is shown that the increase of CCD camera resolution up to 2048 pixels reduces significantly PE and CT. Applying the Hanning window on the final interference pattern resulted effective in reducing the spectral leakage from the Fourier-transformed signal. With this method a reduction of PE and CT with an approximate factor of 5.2 was realized. The noise averaging method from signal overlapping was associated with the rapid reduction of PE and CT for up to 16 signals with an approximate factor of 7.58. A further increase in the number of overlaps impacted very little on PE and CT

LINAC-based radiosurgery has been commissioned at Mother Teresa University Hospital with the prim... more LINAC-based radiosurgery has been commissioned at Mother Teresa University Hospital with the primary aim to treat the tumors, vascular lesions and functional disorders. Due to the size and shape of such targets, small cones are suitable for this technique. Measurements were made to characterize the dosimetric properties of small fields collimators set for PRIMUS Oncor Linac(Siemens). In addition, the geometric and dosimetric accuracy of linac was verified when used with Radionics planning system. Materials/Methods: A set of 12 cones (12.5-40.0mm diameter) was commissioned with the linac and modeled into the planning system Xknife for energies 6MV and 7MV flattening filter free. Output factors, TMRs and OARs were collected in PTW-MP3 water phantom, using PTW Pin point 0.016cm3 chamber. Isocenter position variations with table, gantry, and collimator rotation were found to be <0.5 mm, with a compounded accuracy of less than 1.0 mm. For TPS commissioning various verifications was pe...

European Journal of Medical and Health Sciences, 2020

One of the most important issues in the field of radiotherapy is the correct distribution of the ... more One of the most important issues in the field of radiotherapy is the correct distribution of the dose around the volume of interest or planning target volume (PTV). For making this possible the exact isodose in a treatment plan has to cover the PTV, so it is used the wedge which is a part of the linear accelerator head. Wedge plays the role of a filter and usually it is called wedge filter. The wedge filter is in use almost in all treatment plans, for all the parts of the body. In this paper it is consider the use of the wedge filter for treatment of rectum tumors. The process starts with the scanning of the patient and the deliantion of the interest’s volums in the Monaco system. In the following the imagins have been sent in the treatment planning system for making the nesessary plans for treatment of the rectum. Two plans were done, one with the use of the wedge and the other without using it. The dose volume histogram helps for compering the results of the plans. The best confor...

Isotactic polypropylene (IPP) is a useful thermoplastic with wide range of applications, due to p... more Isotactic polypropylene (IPP) is a useful thermoplastic with wide range of applications, due to properties such as of high tensile strength, hardness, and chemical resistance. The crystallization kinetics and morphology development of pure isotactic polypropylene at different crystallization temperature Tc it was analyzed by optical microscope with polarized light in transmission mode (POM) equipped with hot stage. It was determined nucleation and growth rates of spherulites. The number of nuclei increased and the radial growth rates of spherulites decreased with increasing the rate of super cooling ΔT. The nucleation rate was constant at a predetermined temperature in isothermal crystallization conditions and the results were comparable with the literature. The radial growth rates of spherulites depended from the crystallization temperature. It was analyzed and compared the different morphological structures of pure IPP cooled in different ways: in the water at T = 100°C, in the water T = 0°C and at T = - 10°C.

AIP Conference Proceedings, 2007

In this paper we present some considerations about quantity estimations, regarding the range of i... more In this paper we present some considerations about quantity estimations, regarding the range of interaction and the conservations laws in various types of interactions. Our estimations are done under classical and quantum point of view and have to do with the interaction's carriers, the radius, the influence range and the intensity of interactions.

AIP Conference Proceedings, 2016

In this study we analyzed and compared the dose distribution of different IMRT and VMAT plans wit... more In this study we analyzed and compared the dose distribution of different IMRT and VMAT plans with the intent to provide pre-treatment quality assurance using two different tools. Materials/Methods: We have used the electronic portal imaging device EPID after calibration to dose and correction for the background offset signal and also the Delta4 phantom after en evaluation of angular sensitivity. The Delta4 phantom has a two-dimensional array with ionization chambers. We analyzed three plans for each anatomical site calculated by Eclipse treatment planning system. The measurements were analyzed using γ-evaluation method with passing criteria 3% absolute dose and 3 mm distance to agreement (DTA). For all the plans the range of score has been from 97% to 99% for gantry fixed at 0° while for rotational planes there was a slightly decreased pass rates and above 95%. Point measurement with a ionization chamber were done in additional to see the accuracy of portal dosimetry and to evaluate the Delta4 device to ...

To evaluate the measured of all photon beam data of first Varian True Beam version 2.0 slim model... more To evaluate the measured of all photon beam data of first Varian True Beam version 2.0 slim model, recently commissioned at Nordland Hospital Trust, Bodo. To compare and evaluate the possibility of beam matching with the Clinac2300, for the energies of 6MV and 15 MV. Materials/Methods: Measurements of PDD, OAR, and Output factors were realized with the IBA Blue-phantom with different detectors and evaluated between them for all photon energies: 6MV, 15MV, 6MV FFF and 10MV FFF. The ionization chambers used were Pin Point CC01, CC04, Semiflex CC13 and photon diode by Iba dosimetry. The data were processed using Beizer algorithm with a resolution of 1 mm. The measured depth dose curves, diagonals, OAR, and output factors were imported into Eclipse in order to calculate beam data for the anisotropic analytical algorithm (AAA version 10.0.28) for both the dataset measured with CC04 and CC13 and compared. The model head of 23EX was selected as the most near model to True Beam as a restriction of our version of ...

In Vivo Dosimetry (IVD) is a set of methods used in cancer treatment clinics to determine the rea... more In Vivo Dosimetry (IVD) is a set of methods used in cancer treatment clinics to determine the real dose of radiation absorbed by target volume in a patient’s body. IVD has been widely implemented in radiotherapy treatment centers and is now recommended part of Quality Assurance program by many International health and radiation organizations. Because of cost and lack of specialized personnel, IVD has not been practiced as yet, in Albanian radiotherapy clinics. At Hygeia Hospital Tirana, patients are irradiated with high energy photons generated by Elekta Synergy Accelerators. We have recently started experimenting with the purpose of establishing an IVD practice at this hospital. The first set of experiments was aimed at calibration of diodes that are going to be used for IVD. PMMA, phantoms by PTW were used to calibrate p – type Si, semiconductor diode dosimeters, made by PTW Freiburg for entrance dose. Response of the detectors is affected by energy of the beam, accumulated radiation dose, dose rate, te...

$Research paper thumbnail of The Study of Phase Compound and the Degree of Crystallinity of Recycled LDPE by X-ray Diffractometer and Optical Microscope$

International Journal of Science and Research (IJSR)

In this paper we study the phase compound of semi crystalline structures of recycled LDPE (Low De... more In this paper we study the phase compound of semi crystalline structures of recycled LDPE (Low Density Polyethylene) by Optical Microscopy and X-ray Diffraction techniques. Measurements of optical microscopy were made using the technique of polarized light microscopy in transmission mode (POM). The micrographs taken for all recycled LDPE samples indicate the presence of additives. XRD method is non destructive nature with in-depth crystallographic analysis and for this reason XRD techniques are used in this paper to study the phase compound and to calculate the degree of crystallinity of pure and recycled LDPE. By diffractgrams analyses were identified rutile's and calcite's peak, as additives added in the recycled LDPE. It was analyzed the influence of additives on the degree of crystallinity.

Journal of Applied Polymer Science

D.c. conductivity sigma and thermal degradation measurements on PEDOT:PSS films of different thic... more D.c. conductivity sigma and thermal degradation measurements on PEDOT:PSS films of different thicknesses d = 50, 120 and 180 nm are reported. The experimental results are consistent with a hopping type carrier transport. For the films with thickness d = 50 nm, which consist of almost one single layer of PEDOT:PSS conductive grains, the conductivity and the heat aging are consistent with a hopping transport in a granular metal type structure. However, for films with d = 120 and 180 nm, in which many conductive grains constitute the film thickness, a completely different behaviour is exhibited. An explanation of this is proposed.

Acta Informatica Medica, 2013

Journal of Power Sources, 2004

Journal of Materials Science: Materials in Medicine, 2007

Crystallization kinetics of hydroxyapatite, HAP, in the presence of Leucine, a natural amino acid... more Crystallization kinetics of hydroxyapatite, HAP, in the presence of Leucine, a natural amino acid with hydrophobic side groups, were investigated at conditions of sustained supersaturation, 37 degrees C, pH 7.40, ionic strength 0.15 M. In the presence of Leucine, the crystal growth rates of HAP decreased markedly. Tauhis action is due to adsorption and subsequent blocking of the active growth sites onto the surface of the HAP crystals. The kinetic results revealed that a Langmuir-type adsorption isotherm is followed and an affinity constants of k(aff )=20.26 x 10(2) L/mol for HAP crystal surface were calculated. The apparent order of the crystal growth reaction was found to be equal to two, suggesting a surface diffusion controlled mechanism.

Journal of Crystal Growth, 2002