Mathematical Optimization for the Train Timetabling Problem

AMS Subj. Classification: 90C57; 90C10;Rail transportation is very rich in terms of problems that can be modelled and solved using mathematical optimization techniques. The train scheduling problem as the most important part of a rail operating policy has a very significant impact on a rail company profit considering the fact that from the quality of a train timetable depends a flow of three most important resources on rail network: cars, locomotives and crews. The train timetabling problem aims at determining a periodic timetable for a set of trains that does not violate track capacities and satisfies some operational constraints. In this paper, we developed an integer programming approach for determining an optimal train schedule for a single, one-way track linking two major stations, with a number of intermediate stations between. The application has been tested on a realistic example suggested by the PE “Serbian Railways”. Obtained results show a potential for a practical application of proposed approach

Relationship between genetic polymorphism of k- casein and quantitative milk yield traits in cattle breeds and crossbreds in Serbia

The quality and yield of milk, and therefore of dairy products as well, depends directly on their protein composition. Milk gene proteins represent structural locuses that are functionally associated with milk production. In cattle selection a special importance is attached to the variability of kappa casein (kappa-CN) as one of the four casein milk proteins. Genotypes of 21 Simmental breed cows, 20 crossbred cows obtained by crossing of Simmental and Red Holstein breed, and 25 cows of autochthonous Busha breed were determined for kappa casein by restriction fragment length polymorphism analysis (PCR-RFLP) of amplified DNA. The kappa-CN genotype frequencies for Simmental breed were: 42.8; 47.6 and 9.6 % for AA, AB and BB genotype, for crossbreds: 75.0; 25.0 and 0.0% and for Busha individuals: 41.7; 50.0 and 8.3 %, respectively. Frequencies of A and B alleles, assessed on the basis of genotypic frequencies were 0.667 and 0.333 for Simmental breed, 0.875 and 0.125 for crossbreds and 0.667 and 0.333 for autochthonous Busha cattle breed, respectively. For confirming the phenotypic variability of milk yield in standard lactation, yield of milk fat and the content of milk fat per kappa-CN genotypes within breeds observed the fixed model which included the breed effect, lactation in order and effect of kappa-CN genotype (AA, AB and BB) was used. The kappa-CN genotype statistically significantly (p lt = 0.05) influenced milk yield and highly significantly (p lt = 0.01) milk fat yield, while the content of milk fat was not statistically significantly (p >0.05) influenced in examined animals

The assessment of genetic potential in performance tested gilts by means of selection indexes method

The objective of this research paper was to make an assessment of breeding value of performance tested gilts of Swedish Landrace and F-1 crossbreds of Swedish Landrace and Great Yorkshire by the method of selection index. The traits on whose basis the breeding value was estimated were: daily liveweight gain, average backfat thickness measured at two sites and carcass meat percentage. These traits were corrected for body mass of 100kg by the method of base indexes and the following average values were determined: corrected daily liveweight gain (KZDP) 408.93g/day, corrected average backfat thickness measured at two sites (KSL) 9.77mm and corrected carcass meat percentage (KPM) 61.08%. Studying the effect of genotype, year and birth season of gilts a statistically significant variation (P>0.05) of these traits provoked by the mentioned factors was not determined while the gilts sire statistically highly significantly (P lt 0.001) influenced all studied traits. Heritability coefficients were: h(2)= 0.255 for KZDP, h(2)= 0.356 for KSL and h(2)= 0.349 for KPM. The four selection index equations were constructed among which as the most optimal was chosen the one which includes all three traits (KZDP, KSL and KPM) and whose coefficient of the correlation of selection index and aggregate genotype was r(IAG) = 0.594

Značaj bivola u proizvodnji mleka i stanje populacije u Srbiji

This research paper gives an analysis on the size of world's domestic buffalo populations, their milk production and the size of buffalo population in Serbia. Population of domestic buffalo in the world is constantly increasing so that in 2013 there were 199 783 549 individuals, out of which in India in the same year they raised 57.77% of buffalo world population, in Pakistan 18.87%, and in China 11.64%. The share of total world production of buffalo milk in total world milk production in 2012 was 12.92 % or 97 417 135 t out of which 67.76% was produced in India. In Serbia buffalo is raised in the regions of Raška (about 1000 individuals) and Kosovo. Populations of buffalo in central Serbia show a tendency of decreasing in size what was the reason to start a programme of in situ conservation 10 years ago. On the sample of buffalo population encompassed by the programme of conservation the body measures were analysed indicating that the population of buffalo is quite unequalised and that average values obtained for exterior measures are similar to the results obtained by the authors of earlier period for the population of buffalo in the area of former Yugoslavia.U radu je analizirano brojno stanje domaćih bivola u svetu, proizvodnja mleka bivola, kao i stanje populacije bivola u Srbiji. Populacija domaćih bivola u svetu stalno raste i 2013. godine bilo je 199.783.549 grla, a od tog broja u Indiji je u 2013. godini gajeno 57,77% svetske populacije bivola, u Pakistanu 18,87%, a u Kini 11,64%. Učešće ukupne svetske proizvodnje bivoljeg mleka u ukupnoj svetskoj proizvodnji mleka 2012. godine bilo je 12,92 % ili 97.417.135 t, a od toga je 67,76% proizvedeno u Indiji. U Srbiji bivoli se gaje u području Raške oblasti (oko 1000 bivola) i na području Kosova. Populacija bivola u centralnoj Srbiji ima tendenciju smanjenja veličine, zbog čega je pre 10 godina počeo da se sprovodi program konzervacije. Na uzorku populacije (37 bivolica) obuhvaćene programom in situ konzervacije utvrđene su prosečne vrednosti za telesne mere. Visina grebena bivolica u populaciji koja je merena bila je 125,97 cm, visina krsta 126,98cm, dužina trupa 142,19cm, dubina grudi 68,75 cm, širina grudi 44,48cm, a obim grudi 184,25 cm. Populacija bivolica je bila dosta neujednačena što ukazuje na odsustvo odgajivačko-selekcijskog rada kod bivola u Srbiji u prethodnim decenijama

Contamination of the Šar Mountains Aquatorium – Kosovo with Depleted Uranium

The main objective of this study was to estimate the environmental and health risk of the Šar Mountains (Kosovo) for depleted uranium contamination. The risk assessment of the contamination is needed since, in the spring of 1999, conflict with bombarding took place in the territory of the Western Balkans, during which depleted uranium ammunition was used. In Serbia and Montenegro, such tests were performed; based on them, some territories were decontaminated. Šar Mountains is particularly important as it is one of the few water-rich areas in Kosovo. Therefore, soil and water samples were taken from characteristic places in the Šar Mountains aquatorium. Tests of the samples were performed under well-controlled conditions. The measurement uncertainty was less than 5%. Based on the obtained results, it was concluded that there was no contamination of the Šar Mountains with depleted uranium. This conclusion can be extended to the broader area around the Šar Mountains, as it is a safe area surrounded by high mountains

Mogućnosti upotrebe selekcijskog indeksa u proceni priplodne vrednosti krava Holštajn rase u Srbiji

The conducted research was aimed at constructing equations of selection index that would be used in the selection of the Holstein-Friesian breed animals in Serbia. The construction of the selection index includes the most important milk traits observed in standard lactation: milk yield (MY305), milk fat content (% MF305) and protein content (% MP305). The variance and covariance necessary for the construction of selection index are calculated using the mixed model by the method of least squares. The economic value of traits is expressed as a ratio of relative changes in costs per unit of traits included in the selection index. Livestock included in the research produced, in the first standard lactation, an average of 7681 kg of milk with 3.58% milk fat and 3.28% protein. The equation of the selection index presented in the paper is selected from the group of equations of selection index, as an equation with the highest correlation between the equation and the aggregate genotype, which amounted to 0.2156.Sprovedeno istraživanje imalo je za cilj konstruisanje jednačine selekcijskog indeksa koja bi se koristila u odabiru grla holštajn-frizijske rase u Srbiji. U konstrukciju selekcijskog indeksa uključene su najvažnije osobine mlečnosti posmatrane u standardnoj laktaciji: prinos mleka (PM305), sadržaj mlečne masti (%MM305) i sadržaj proteina (%MP305). Varijanse i kovarijanse neophodne za konstrukciju selekcijskog indeksa izračunate su primenom mešovitog modela metodom najmanjih kvadrata. Ekonomska vrednost osobina je izražena kao odnos relativne promene troškova po jedinici osobina uključenih u selekcijski indeks. Grla obuhvaćena istraživanjem prosečno su proizvela u prvoj standardnoj laktaciji 7681 kg mleka sa 3,58 % mlečne masti i 3,28% proteina. Jednačina selekcijskog indeksa prikazana u radu odabrana je iz grupe jednačina selekcijskog indeksa, kao jednačina sa najvećom korelacijom između jednačine i agregatnog genotipa, koja je iznosila 0,2156.

Procena strukture mlečnih farmi i karakteristika sistema za proizvodnju mleka u Srbiji

In order to have a more precise description of dairy farm structure and characteristics of dairy production systems, as well as to assess possibilities for improving production and farming conditions in which milk production is organized, a survey based research was directed at a select group of farms across the Serbia. 1180 questionnaires have been mailed to farmers whose farms are registered for either cattle or mixed production. Questionnaire was divided into 6 sections: general information of the farm, agricultural and structural information, zootechnical information, sanitary and veterinarian information, information about education and extension, and information on the perspectives of future farming. About 59% of analyzed farms have size up to 20 ha, with average size of about 10 ha. On the other hand, about 55% farms raises up to 15 cows and heifers with average of 6 heads per farm, while 3% of farms have more than 200 cows and heifers. Over 86% of surveyed farmers intend to expand existing farm production, mainly by increasing the number of animals, stricter selection and improvement of the conditions for feeding, housing, care and milking. About 75% of farmers have expressed a positive expectation from future membership of Serbia in EU, although these expectations are not clearly defined.U cilju preciznijeg opisa strukture mlečnih farmi i karakteristika sistema za proizvodnju mleka, kao i procene mogućnosti za unapređenje proizvodnje i farmskih uslova u kojima se proizvodnja mleka organizuje, sprovedena je anketa među poljoprivrednim proizvođačima (farmerima) širom Srbije. Ukupno je poslato 1180 anketa farmerima čije su farme registrovane za govedarsku ili mešovitu proizvodnju. Upitnik koji je poslat farmerima sastojao se iz 6 delova i obuhvatao je opšte informacije o farmi, poljoprivredne i strukturne informacije, zootehničke informacije, sanitarne i veterinarske aspekte proizvodnje, edukaciju i savetodavstvo, kao i perspektive budućeg poslovanja. Oko 59% analiziranih farmi ima veličinu do 20ha, sa prosekom od oko 10ha. Sa druge strane, na oko 55% farmi odgaja se do 15 krava i junica, sa prosekom od 6 grla po farmi. Preko 86% anketiranih farmera namerava da proširi postojeću proizvodnju i to uglavnom povećanjem broja životinja, strožijom selekcijom roditeljskih parova, kao i unapređenjem uslova ishrane, smeštaja i nege. Oko 75% anketiranih farmera izrazilo je pozitivna očekivanja od budućeg članstva Srbije u EU, iako ta očekivanja nisu uvek jasna ili precizno definisana

Fenotipska i genetska povezanost osobina mlečnosti u prve tri uzastopne laktacije crno belih krava

In order to conduct selection on the larger number of traits, that are significant from the economic aspect, it is necessary to know the direction and strength of correlation between observed traits. In this research average values and variability of the most significant milk yield traits as well as coefficients of genetic and phenotype correlations are described. This research was conducted on 1369 cows that had finished their first three lactations in period from 2006 to 2010th year. Cattle were bread at 7 farms of Agricultural Corporation Belgrade and they are descendants of 29 bulls. The following traits were researched: milk yield, milk fat content and milk fat yield. Obtained genetic correlation values in this research were from -0.375 between milk fat content in entire lactation and milk yield in standard lactation, up to 0.998 for milk fat content in entire and standard lactation. Obtained phenotype correlation values were from -0.207 between milk yield in standard lactation and milk fat content in entire lactation up to 0.958 between milk yield and milk fat content in entire lactation.U cilju sprovođenja selekcije na veći broj osobina, koje imaju primarni značaj sa ekonomskog aspekta proizvodnje mleka, neophodno je poznavanje smera i jačine povezanosti između osobina. U radu su prikazane prosečne vrednosti i varijabilnost najvažnijih osobina mlečnosti, kao i koeficijenti fenotipskih i genetskih korelacija. Istraživanjem je obuhvaćeno 1369 grla koja su imala zaključene prve tri laktacije u periodu od 2006. do 2010. godine. Grla su gajena na 7 farmi Poljoprivredne korporacije Beograd i potomci su 29 bikova-očeva. Istraživanjem su obuhvaćene sledeće osobine mlečnosti: prinos mleka, sadržaj mlečne masti i prinos mlečne masti. Vrednosti koeficijenata fenotipskih korelacija imali su vrednosti od - 0.207 između prinosa mleka u standardnoj laktaciji i sadržaja mlečne masti u celoj laktaciji, do 0.958 između prinosa mleka i prinosa mlečne masti u celoj laktaciji. Vrednosti genetskih korelacija utvrđeni u istraživanju imali su vrednosti od -0.375 između sadržaja mlečne masti u celoj laktaciji i prinosa mleka u standardnoj laktaciji, do 0.998 za sadržaj mlečne masti u celoj i standardnoj laktaciji

Procena priplodne vrednosti krava crno-bele rase upotrebom selekcijskog indeksa

The objective of this study was a construction of selection index on the basis of whose score the cows could be graded during their selection and formation of parent pairs. The most important milk yield traits in standard lactation: milk yield (PM305), milk fat content (%MM305) and protein content (%MP305) were included in the construction of selection index. Variances and covariances deemed necessary for construction of selection index were calculated by use of the mixed model of the Least Squares method. Economic value of the traits was expressed as a relationship of relative cost changes per unit of the traits included in the selection index. The individuals included in the trial on average produced 8261 kg milk with 294.14 kg milk fat and 270.07 kg protein in standard lactation. Equation of selection index used in this study was chosen from a set of selection index equations, as an equation having the highest correlation between the equation and aggregate genotype which amounted to 0.4275.Cilj istraživanja bila je konstrukcija selekcijskog indeksa, na osnovu čijeg skora bi se mogle rangirati krave prilikom njihovog odabira i formiranja roditeljskih parova. U konstrukciju selekcijskog indeksa uključene su najvažnije osobine mlečnosti posmatrane u standardnoj laktaciji: prinos mleka (PM305), sadržaj mlečne masti (%MM305) i sadržaj proteina (%MP305). Varijanse i kovarijanse neophodne za konstrukciju selekcijskog indeksa izračunate su primenom mešovitog modela metodom najmanjih kvadrata. Ekonomska vrednost osobina je izražena kao odnos relativne promene troškova po jedinici osobina uključenih u selekcijski indeks. Grla obuhvaćena istraživanjem prosečno su proizvela u standardnoj laktaciji 8261 kg mleka sa 294,14 kg mlečne masti i 270,07 kg proteina. Jednačina selekcijskog indeksa prikazana u radu odabrana je iz grupe jednacina selekcijskog indeksa, kao jednacina sa najvećom korelacijom između jednačine i agregatnog genotipa, koja je iznosila 0,4275

Application of complex statistical distributions and natural isotopes of hydrogen and oxygen for assessment of water origin in Šar mountains aquatorium

This study considers the possibility of applying natural isotopes of water, tritium, and oxygen 18O, to analyze the connection between groundwater, surface, and precipitation waters. This analysis also enables the determination of the age of groundwater, separated from the cycle of water circulation in nature. Based on these methods, it is possible to reliably determine, by chronologically accurate method, the possibility of industrial application and application for human needs of the waters of this aquatorium. © 2020, Vinca Inst Nuclear Sci. All rights reserved