Aleksander Xhuvani University of Elbasan
Elbasan, Albania
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Halili D.,Aleksander Xhuvani University of Elbasan | Berberi P.,Polytechnic University of Tirana | Mitrushi D.,Polytechnic University of Tirana | Muda V.,Polytechnic University of Tirana | And 2 more authors.
AIP Conference Proceedings | Year: 2016

Albania is a sunny region with high annual average insolation of 7.63 kWh/m2∗d. Use of solar collectors to provide hot water for domestic use results to be very cost effective. Mean cost of thermal energy produced by solar collectors is 0.046Euro/kWh. Even geographically the area of Albania is very limited, only 28 000 km2, there is an important variation of insolation from one site to the other due to variation of cloud coverage. In this study, we give a map of distribution of solar energy budget and costs of thermal energy produced by solar collectors in main cities of Albania. The mean annual cost of energy varies from 0.037 to 0.069 €/ kWh, while the price of electrical energy actually used for electric boilers is as much as 0.081 €/kWh. Also, annul cost saved by using solar collectors instead of an electrical boiler for producing hot water varies from one site to the other from 305 to 253 €/y. © 2016 AIP Publishing LLC.

Berdufi I.,University of Tirana | Berberi P.,Polytechnic University of Tirana | Mitrushi D.,Polytechnic University of Tirana | Muda V.,Polytechnic University of Tirana | And 2 more authors.
AIP Conference Proceedings | Year: 2016

The paper is focused on analyzing the performance of the first grid connected PV system recently installed in Albania. The system is composed by two sets of 12 panels of poly crystalline silicon modules connected in parallel, each with open circuit voltage 44.8V DC and nominal power is 195Wp. Meteorological data are measured using a meteorological station DAVIS. Aim of the study is to define an empirical function best fitting the experimental relation between meteorological data and power output of the system. Two empirical energetic approximation functions, Durisch and Evans models, were tested and needed parameters calculated. Both approximation models predict higher values of output electrical energy compared with experimental ones. Good linear correlation between three sets of data shows that duly correction of Durisch and Evans model with an experimentally defined factor makes them suitable for describing the PV system. © 2016 AIP Publishing LLC.

Mitrushi D.,Polytechnic University of Tirana | Berberi P.,Polytechnic University of Tirana | Berdufi I.,University of Tirana | Muda V.,Polytechnic University of Tirana | And 2 more authors.
AIP Conference Proceedings | Year: 2016

The main objective of this study is to compare data provided by Database of NASA with available ground data for regions covered by national meteorological net NASA estimates that their measurements of average daily solar radiation have a root-mean-square deviation RMSD error of 35 W/m2 (roughly 20% inaccuracy). Unfortunately valid data from meteorological stations for regions of interest are quite rare in Albania. In these cases, use of Solar Radiation Database of NASA would be a satisfactory solution for different case studies. Using a statistical method allows to determine most probable margins between to sources of data. Comparison of mean insulation data provided by NASA with ground data of mean insulation provided by meteorological stations show that ground data for mean insolation results, in all cases, to be underestimated compared with data provided by Database of NASA. Converting factor is 1.149. © 2016 AIP Publishing LLC.

Grabocka J.,University of Hildesheim | Bedalli E.,University of Tirana | Bedalli E.,Aleksander Xhuvani University of Elbasan | Schmidt-Thieme L.,University of Hildesheim
Advances in Intelligent Systems and Computing | Year: 2013

Time-series classification has gained wide attention within the Machine Learning community, due to its large range of applicability varying from medical diagnosis, financial markets, up to shape and trajectory classification. The current state-of-art methods applied in time-series classification rely on detecting similar instances through neighboring algorithms. Dynamic Time Warping (DTW) is a similarity measure that can identify the similarity of two time-series, through the computation of the optimal warping alignment of time point pairs, therefore DTW is immune towards patterns shifted in time or distorted in size/shape. Unfortunately the classification time complexity of computing the DTW distance of two series is quadratic, subsequently DTW based nearest neighbor classification deteriorates to quartic order of time complexity per test set. The high time complexity order causes the classification of long time series to be practically infeasible. In this study we propose a fast linear classification complexity method. Our method projects the original data to a reduced latent dimensionality using matrix factorization, while the factorization is learned efficiently via stochastic gradient descent with fast convergence rates and early stopping. The latent data dimensionality is set to be as low as the cardinality of the label variable. Finally, Support Vector Machines with polynomial kernels are applied to classify the reduced dimensionality data. Experimentations over long time series datasets from the UCR collection demonstrate the superiority of our method, which is orders of magnitude faster than baselines while being superior even in terms of classification accuracy. © 2013 Springer-Verlag.

Devolli A.,Aleksander Xhuvani University of Elbasan | Shabani L.,University of Tirana
Journal of Environmental Protection and Ecology | Year: 2011

The hygiene control in a brewery ensures a very good quality of the final product and minimises the risk of contamination. Microbiological control is a regulative system, which function is the prevention and elemination of contaminating microorganisms to protect and to ensure what is the most important for us, the quality of the beer. It is important to detect as soon as possible the dangerous microorganisms that affect the quality, through constant hygienic control, and to optimise the cleaning procedures to improve the economic efficiency. The hygienic control for detection of the presence of harmfull microorganisms always used rapid tests and microbiological cultivation methods. A total control of hygenic conditions in a brewery, from the equipment used in the beer production in boiling of wort, fermentation process, filtration, packing of the product to all environment of the brewery has been done. The present study examines the growth of microorganisms in a brewery. Beer spoilage microorganisms such as lactic acid and acetic acid bacteria, enterobacteria and yeasts were shown to be present on the materials surface of the brewing process. To achieve this goal, are done a lot of microbiological analyses using some standard and selective media, suitable for the examination of contaminanting microorganisms. The results of this study reveal that the hygiene control in a brewery is very important to provide a high-quality beer.

Kusk K.O.,Technical University of Denmark | Avdolli M.,Aleksander Xhuvani University of Elbasan | Wollenberger L.,Technical University of Denmark
Environmental Toxicology and Chemistry | Year: 2011

Benzophenone (BP)-type ultraviolet (UV) filters are widely used in cosmetic and sunscreen products and can enter the aquatic environment. Therefore, we investigated the subchronic toxicity of 2,4-dihydroxybenzophenone (BP1) on the marine calanoid copepod Acartia tonsa in an early life-stage development study. Since developmental endpoints depend on environmental conditions, a preceding study of A. tonsa development was performed at three temperatures, four salinities, four light:dark regimes, six food densities, and four culture densities. Times elapsed until 50% of the population had reached a copepodite stage (DT 1/2) at the different conditions were calculated. The DT 1/2 values decreased from 296h at 15°C to 89h at 25°C and were also affected by salinity (126h at 15‰ and 167h at 30‰), whereas the light:dark regime and culture density influenced development only to a minor extent. BP1 was found acutely toxic at 2.6mg/L (48-h median lethal concentration [LC50]). The toxicity of BP1 on early life-stage development was studied in combinations of three temperatures (15, 20, 25°C) and three salinities (15, 20, 25‰) using five toxicant concentrations between 0.051 and 2mg/L in each scenario. Concentrations causing 10 and 50% inhibition of development (EC10 and EC50) were determined. Acartia tonsa was most resistant towards BP1 at 20°C where an EC50 of 1.1mg/L was found, whereas EC50 values were significantly lower at 15°C (0.49mg/L) and 25°C (0.77mg/L), respectively. The EC50 also decreased with increasing salinity. Our results demonstrate that environmental conditions do influence toxicity test results; thus, they need to be considered carefully when developing test protocols as well as for environmental risk assessments of chemicals. © 2010 SETAC © 2011 SETAC.

Grabocka J.,University of Hildesheim | Bedalli E.,Aleksander Xhuvani University of Elbasan | Schmidt-Thieme L.,University of Hildesheim
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

Semi-supervised learning is an eminent domain of machine learning focusing on real-life problems where the labeled data instances are scarce. This paper innovatively extends existing factorization models into a supervised nonlinear factorization. The current state of the art methods for semi-supervised regression are based on supervised manifold regularization. In contrast, the latent data constructed by the proposed method jointly reconstructs both the observed predictors and target variables via generative-style nonlinear functions. Dual-form solutions of the nonlinear functions and a stochastic gradient descent technique which learns the low dimensionality data are introduced. The validity of our method is demonstrated in a series of experiments against five state-of-art baselines, clearly improving the prediction accuracy in eleven real-life data sets. © 2014 Springer International Publishing.

Kushi E.,Aleksander Xhuvani University of Elbasan
Journal of Environmental Protection and Ecology | Year: 2011

Nowadays the development of tourism must be considered as tightly connected with environment protection, which means the protection of the basic values of the tourism destinations. Since tourism is one of the most important industries in Albania, this paper provides an analysis of the relationship between sustainable tourism and environment protection in this country. It highlights that while tourism provides considerable economic benefits for many regions and communities in Albania, its rapid expansion can also be responsible for adverse environmental impact. The paper also identifies that the main environmental impacts of tourism are the pressure on natural resources, pollution and waste generation and damage to ecosystems. Furthermore, it shows that environmental degradation poses threat to tourism. Therefore, the development of the international tourism market in Albania needs to be cautious, as running for short-term profits, that further damage the environment, exposes a high risk of failure for the tourist activities. This may solely create an image with negative effects in long run that will require time to be reversed. Finally, the analysis suggests the need to promote sustainable tourism development in order to minimise its environmental impacts and to ensure more sustainable management of natural resources.

Turhani A.,Aleksander Xhuvani University of Elbasan
Journal for East European Management Studies | Year: 2013

Service infrastructure public-private partnerships (PPPs) in Albania have revealed significant governance problems. The aim of this research is to examine the technical-rational and social contractual issues of PPPs within the broad context of risk, and accordingly propose a governance framework. The research builds on international PPP literature to develop an analytical conceptualization. It uses document review and interviews to construct a case study of a Concession Contract for the Water Supply in Elbasan, Albania, which became operational in October 2002 and failed in December 2007. The research indicates that failure within this so-called PPP largely occurred within the technical-rational governance system due to unforeseen risks. This led to a breakdown in the social contract, through political risk. It is required a governance system that enhances risk assessment and diminishes the likelihood of negative political behaviors.

Shqau G.,Aleksander Xhuvani University of Elbasan
Journal of Environmental Protection and Ecology | Year: 2012

Elbasan is considered one of the most important cities of Albania. It is well known on account of education as well as because of environmental pollution. In addition, recently urban waste is affecting the health of the population and performance in the city. Given the favourable geographical position and cultural values of this city and the historic values both inside and outside the city, the area would be of great significance for the development of tourism. Management controlling pollution and the increase of the readiness and motivation for a sustainable tourism in several aspects are two main factors that must be combined for sustainability and the influx of visitors. Using different data from different local institutions, it is identified the level of pollution in some areas as air pollution, urban waste, recycling, water pollution, problems with car pollution, etc., which gives the possibility to make relevant recommendations for managers to curb them in the menu to open more sustainable tourism route. The current level of tourism in Elbasan in some perspective becomes the link between these factors in the efforts to reduce waste for a better development of tourism and sustainable tourism.

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