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1

An application of ahp method for examining the transport plan of passenger trains in bulgarian railway network

Stoilova S., Nikolova R.

Transport Problems

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2018

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T. 13, z. 1

37--48

EN

In this study, a methodology was developed for transport plan selection of intercity trains in railway network using the method of Analytic Hierarchy Process (AHP). For studying the transport plan, the following indicators have been chosen: the transport satisfaction, average number of train stops, average distance travelled, average speed, reliability, availability of service with direct transport and transport capacity. The methodology includes determination of variant schemes of transportation; determination of the number of trains by criterion of minimum direct operating costs for transportation of each variant scheme using linear optimization model; application of AHP method to define the weights of criteria and ranking the variants schemes; and selection of an optimal transport plan according to the criterion of a minimum ratio of normalized direct operating costs to the AHP score. The methodology was experimented in Bulgarian railway network.

2

Classifying railway passenger stations for use transport planning – application to Bulgarian railway network

Stoilova S., Nikolova R.

Transport Problems

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2016

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T. 11, z. 2

143--155

EN

A methodology for the classification of railway passenger stations was developed in this study. Four groups of factors are defined to study the characteristics of the station: potential of the town, importance of the town, infrastructural factors, and characteristics of passengers. In the research we investigated 18 factors and studied 98 passenger stations of railway network in Bulgaria. The method of principal components has been applied for grouping the factors and cluster analysis has been applied to classify the stations. The factors have been classified into 4 components by the method of principal components. The stations have been classified into 6 groups using hierarchical cluster analysis. The methods, Average linkage between group and Within-groups linkage, and distance-type measures Euclidean distance and Squared Euclidean distance were compared to verify the results of cluster analysis. The grouping of the stations has been used for the determination of the stops for categories intercity passenger trains. The main groups of stations for servicing express trains are the first, second, third, fourth and fifth groups. In the sixth group are stations for servicing fast passenger trains. The methodology can be applied to the study of all stations and stops in the rail network.

FR

Dans cette étude est élaborée la méthodologie de classification des gares de passagers. On a déterminé 4 groupes de facteurs pour l’étude des caractéristiques des gares: le potentiel de la ville, importance de la ville, facteurs infrastructurels et caractéristiques des passagers.18 facteurs sont étudiés au total. On a étudié 98 gares de passagers du réseau de fer de la Bulgarie. On a appliqué les méthodes des composantes générales pour le groupement des facteurs et une analyse de cluster pour le classement des gares. D’après la méthode des composantes générales les facteurs sont classifiés en 4 groupes. D’après la méthode de l’analyse hiérarchique les gares sont classifiées en 6 groupes. Les méthodes de liaison moyenne entre le groupe et les intra-groupes de liaison et la distance de type Euclidienne au carré ont été comparées à la verification des résultats de l’analyse de cluster. Le groupement des gares est utilize pour déterminer les arrêts des cathégories des trains de passagers interurbains. Les groups de gares essentiels concernant le service des trains express sont premier, deuxième, troisième, quatrième et cinquième groupe. Le sixième groupe comprend les gares pour le service des TGV. La méthodologie peut être appliquée pour l’étude de toutes les gares et stations dans le réseau de chemin de fer.

3

Crystal structure and spectroscopic properties of 4-acetaminopyridine and its protonated form

Koleva B.B., Nikolova R., Tchapkanov A., Kolev T., Mayer-Figge H., Spiteller M., Sheldrick W.S.

Polish Journal of Chemical Technology

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2009

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Vol. 11, nr 3

35-40

EN

4-Acetaminopyridine dihydrate and its protonated form, stabilized as the hydrochloride salt have been synthesized and spectroscopic elucidated in solution and in the solid-state by means of the inear-polarized solid state IR-spectroscopy (IR-LD), UV-spectroscopy, TGA, DSC, and the positive and negative ESI MS. Quantum chemical calculations were used to obtain the electronic structure, vibrational data and the electronic spectra. The spectroscopic and theoretical data are compared with the structure of the first compound obtained by single crystal X-ray diffraction. The effect of Npy protonation on the optical and magnetic properties of a 4-acetaminopyridine is discussed.