Analysis of the impact of injuries caused by the influence of mechanical and abiotic factors on the occurrence of harmful fungal organisms

U radu je istraživan aspekt pojave patogenih mikroorganizama na bukovom drvetu u odnosu na prisustvo ozleda na stablima, u cilju zaštite i očuvanja ove vrste u Srbiji. Istraživanja su vršena u istočnoj Srbiji, u brdskoj šumi bukve Fagetum moesiacae submontanum, generativnog porekla. Ispitivanjem je obuhvaćeno dva lokaliteta na 51 oglednoj parceli, sa ukupno 829 stabala i konstatovano je prisustvo 21 vrsta gljiva. Na prvom lokalitetu konstatovano je da pojava gljiva prvenstveno zavisi od prisustva mehaničkih oštećenja na stablima (čak 73.46%), a gotovo uopšte nije u vezi sa prisustvom abiotičkih oštećenja (svega 3.21%). Na drugom lokalitetu postoji jaka korelaciona veza između pojave gljiva i prisustva mehaničkih oštećenja - 51.88%, kao i između gljiva i abiotičkih oštećenja - 47.96%. Konstatovano je da za zdravstveno stanje visokih bukovih sastojina izuzetan značaj ima pažljivo i pravilno manipulisanje prilikom seče, a svaka ozleda na bukovim dubećim stablima počinjena pri seči je otvoren put za zarazu patogenim mikroorganizmima.The research described in this paper is focused on the occurrence of pathogenic microorganisms on beech trees relative to the presence of tree injuries, with the aim to ensure protection and preservation of this species in Serbia. The research was conducted in Eastern Serbia, in a hillside beech forest Fagetum moesiacae submontanum of generative origin. The testing was carried out on two sites over 51 testing plots, with a total of 829 trees and 21 species of identified fungi. On the first site it was found that the appearance of fungi primarily depends on the presence of mechanical damage on trees (as much as 73.46%), while the presence of abiotic damage has almost no bearing (only 3.21%). On the second site there was a strong correlation link between the occurrence of fungi and presence of mechanical damage - 51.88%, as well as between the fungi and abiotic damage - 47.96%. The health condition of high beech stands was found to be heavily dependent on careful and proper manipulation during harvesting, while each injury inflicted on a beech live tree during logging opens the door to infection with pathogenic microorganisms

A Proposed Method for Determining Propulsion Coefficient Based on Testing Motor Freighters on Danube Waterway Network

The paper presents a proposal of mathematical models for the determination of propulsion coefficient, eta pp, intended for the analysis of motor freighters applied on the river watercourses. As the main paper contribution three different model types are developed, depending on the variable which contributes to eta pp value. These variables are: 1. the freighter sailing velocity, (nu); 2. the installed capacity of the main drive motor of outboard unit, (N-inst); 3. the combination of these two variables, (N-inst, nu). The models are verified on the examples of several motor freighters which are applied at Danube river. The special attention is paid to the determination of the optimum approximation function in each case. In all three cases it is a quadratic function. The correlation coefficient for the comparison in all analyzed examples is higher than 0.87, being even higher than 0.99 for the first model

Multi-criteria decision making in container transport

Kontejnerski transport danas u okviru svetske globalizacije privrede ima veoma važnu ulogu u prevozu robe sa konstantnom tendencijom rasta. Prednosti kontejnerskog transporta prepoznate su još 80-ih godina prošlog veka, a odnose se na celu privredu, pa čak i društvo u celini. Povećava se broj privrednih subjekata uključenih u proces, poboljšana je koordnacija i upravljanje transportom, omogućeno je ostvarivanje učinaka ekonomije obima u modalitetu prevoza "od vrata do vrata", a sve je to dovelo do smanjenja troškova i povećanja dobiti. Transportni troškovi i tranzitno vreme predstavljaju dva najčešće razmatrana problema prilikom transporta kontejnera. Takođe, ni emisija ugljen-dioksida više se ne može ignorisati: kompanije imaju moralnu obavezu da posluju na održiv način, a kupci postaju sve više i više svesni ogromnog uticaja na životnu sredinu. Osnovni cilj doktorske disertacije je postavka koncepta kojim se povezuje više različitih vidova transporta i stvaranje novog generičkog znanja za donošenje najpovoljnije odluke u smislu više usvojenih raznorodnih kriterijuma: transportni troškovi, tranzitno vreme, emisija ugljen-dioksida. U radu je generisan matematički model koji pruža priliku da posmatramo, pored najpovoljnijeg, i ceo spektar potencijalnih rešenja, dajući nam mogućnost njihovog rangiranja, posmatrajući tri raznorodna kriterijuma istovremeno. Takođe, razvijen je i poseban programski paket za proces unapređenja poslovanja logističkih kompanija kroz kontinualno praćenje neprekidnih promena na tržištu. Prednost modela je da se može primeniti na različite čvorove i kontejnerske robne tokove u transportnim mrežama uzimajući u obzir koncept kojim se povezuje više različitih vidova transporta. U praktičnom domenu, dobijeni rezultati pružaju mogućnost kompanijama da donose odluke o transportnim rutama uzimajući u obzir sva tri posmatrana kriterijuma istovremeno, ostavljajući mogućnost odluke u zavisnosti od težinskih koeficijenata koji su u posmatranom momentu najvažniji.Container transport today plays a very important role in the transport of goods with a constant tendency of growth in the context of global economic globalization. The advantages of container transport have been recognized since the 1980s, and they relate to the whole economy and even society as a whole. Increased number of business entities involved in the process, improved coordination and transport management, enabled the achievement of economies of scale in door-to-door modality, all of which led to cost savings and profit increases. Transportation costs and transit time are the two most commonly considered problems in container transport. Also, carbon dioxide emissions can no longer be ignored: on the one hand, companies have a moral obligation to operate in a sustainable way, and on the other hand, as customers become more and more aware of the enormous impacts on the environment. The main goal of the doctoral dissertation is the concept of multimodalism and the creation of a new generic knowledge for making the optimal decision in terms of more adopted heterogeneous criteria: transport costs, transit time, carbon dioxide emissions. In this paper a mathematical model is generated and provides the opportunity to observe, in addition to the optimal, full spectrum of possible solutions, giving us the possibility of their ranking, observing the three heterogeneous criteria at the same time. Also, a special software package for the process of improving the operations of logistics companies has been developed through the continuous monitoring of uninterrupted changes in the market. The advantage of the model is that it can be applied to different nodes and container merchandise flows in intermodal networks, taking into account concept of multimodalism by itself. In the practical domain, the expected results provide companies with the ability to make decisions about transport routes, taking into account all three optimized criteria, leaving the possibility of decision depending on the weight coefficients that are at the moment at stake as most important

A Proposed Method for Determining Propulsion Coefficient Based on Testing Motor Freighters on Danube Waterway Network

The paper presents a proposal of mathematical models for the determination of propulsion coefficient, eta pp, intended for the analysis of motor freighters applied on the river watercourses. As the main paper contribution three different model types are developed, depending on the variable which contributes to eta pp value. These variables are: 1. the freighter sailing velocity, (nu); 2. the installed capacity of the main drive motor of outboard unit, (N-inst); 3. the combination of these two variables, (N-inst, nu). The models are verified on the examples of several motor freighters which are applied at Danube river. The special attention is paid to the determination of the optimum approximation function in each case. In all three cases it is a quadratic function. The correlation coefficient for the comparison in all analyzed examples is higher than 0.87, being even higher than 0.99 for the first model

Application of a mathematical model for container transport flow of goods: from the far east to Serbia

Container transport represents a key component of intermodal transport and a substantial contribution to the rapidly growing international trade. The container trade should be optimal to provide a suitable resource utilisation and profitability to key operators, providing them an easy and relatively cheap access to international markets. Numerous algorithms have been generated to provide an efficient solution to optimisation problems in container trade. This paper analyses the supply-chain network focusing on container import from the Far East to Serbia through selected Mediterranean ports (Koper, Rijeka, Bar, Thessaloniki and Constanta). An optimisation mathematical model was developed, minimising the transit time and transportation costs of container imports to Serbia, by means of using various liner shipping services on the deep-short sea and truck-rail-barge inland transport networks from selected ports. By using the bi-objective model for container flows from the Far East through Mediterranean ports, the optimal path for container import to Serbia has been determined. Certain groups of customers require the lowest freight rates, while others give priority to a faster delivery

Application of a mathematical model for container transport flow of goods: from the far east to Serbia

Container transport represents a key component of intermodal transport and a substantial contribution to the rapidly growing international trade. The container trade should be optimal to provide a suitable resource utilisation and profitability to key operators, providing them an easy and relatively cheap access to international markets. Numerous algorithms have been generated to provide an efficient solution to optimisation problems in container trade. This paper analyses the supply-chain network focusing on container import from the Far East to Serbia through selected Mediterranean ports (Koper, Rijeka, Bar, Thessaloniki and Constanta). An optimisation mathematical model was developed, minimising the transit time and transportation costs of container imports to Serbia, by means of using various liner shipping services on the deep-short sea and truck-rail-barge inland transport networks from selected ports. By using the bi-objective model for container flows from the Far East through Mediterranean ports, the optimal path for container import to Serbia has been determined. Certain groups of customers require the lowest freight rates, while others give priority to a faster delivery

A review of multi-objective optimization of container flow using sea and land legs together

Intermodalni transport je sistem koji podrazumeva prevoz 'od vrata do vrata' pod odgovornošću jednog prevoznika tj. operatora intermodalnog transporta, uz učešće najmanje dva vida transporta (u prevozu tereta bez promene tovarno manipulativne jedinice). Kontejnerski transport je glavna komponenta intermodalnog transporta i međunarodne trgovine. Kontejnerski transportni tok bi trebalo da bude optimalan kako bi se osiguralo pravilno korišćenje resursa i kako bi se omogućila profitabilnost korisnika. Razni višekriterijumski evolucioni algoritmi su razvijeni da efikasno reše probleme optimizacije u kontejnerskom transportu. Ovaj rad predstavlja kratak pregled problema optimizacije u intermodalnom transportu posmatrajući jedan transportni lanac u kome se transport kontejnera obavlja morem i kopnom uzimajući u obzir tri najčešće razmatrana optimizaciona kriterijuma (transportni troškovi, tranzitno vreme i emisija ugljen-dioksida).Intermodal freight transportation refers to a multi-modal chain of container-transportation services which usually links the initial shipper to the final consignee of the container (door-to-door service) and takes place over long distances. Container transportation is a major component of intermodal transportation and international commerce. Container flow should be optimal to ensure proper resource utilization and profitability to players. Various multi-objective evolutionary algorithms have been developed to efficiently solve optimization problems in container flows. This paper presents a short review of optimization problems in intermodal transport using sea and land legs together regarding three mostly observed objectives (transport cost, transit time and CO2 emissions)

A review of multi-objective optimization of container flow using sea and land legs together

Intermodalni transport je sistem koji podrazumeva prevoz 'od vrata do vrata' pod odgovornošću jednog prevoznika tj. operatora intermodalnog transporta, uz učešće najmanje dva vida transporta (u prevozu tereta bez promene tovarno manipulativne jedinice). Kontejnerski transport je glavna komponenta intermodalnog transporta i međunarodne trgovine. Kontejnerski transportni tok bi trebalo da bude optimalan kako bi se osiguralo pravilno korišćenje resursa i kako bi se omogućila profitabilnost korisnika. Razni višekriterijumski evolucioni algoritmi su razvijeni da efikasno reše probleme optimizacije u kontejnerskom transportu. Ovaj rad predstavlja kratak pregled problema optimizacije u intermodalnom transportu posmatrajući jedan transportni lanac u kome se transport kontejnera obavlja morem i kopnom uzimajući u obzir tri najčešće razmatrana optimizaciona kriterijuma (transportni troškovi, tranzitno vreme i emisija ugljen-dioksida).Intermodal freight transportation refers to a multi-modal chain of container-transportation services which usually links the initial shipper to the final consignee of the container (door-to-door service) and takes place over long distances. Container transportation is a major component of intermodal transportation and international commerce. Container flow should be optimal to ensure proper resource utilization and profitability to players. Various multi-objective evolutionary algorithms have been developed to efficiently solve optimization problems in container flows. This paper presents a short review of optimization problems in intermodal transport using sea and land legs together regarding three mostly observed objectives (transport cost, transit time and CO2 emissions)

Display probability of symbol errors for MQAM on Rician fading channel based on MGF method

We present a new method for calculating the probability of error per symbol (Symbol Error Probability, SEP) of M-ary Quadrature Amplitude Modulation (MQAM) over a slow, flat, identically independently distributed Rician fading channels. Since fading is one of the major constraints in wireless communications, the diversity modulation technique is used for the efficient transfer of message signals. Exact analysis of error probability per symbol for MQAM, transmitted over Rician fading channels, is performed by N branches of diversity reception using maximum ratio of signal-to-noise power (maximal-ratio-combining, MRC), where the information in the channel on the receiver side is known. We also analyzed the performances of MQAM over Rician fading channels are here also analyzed. Approximate formula is used to represent SEP for MQAM transmitted over Gaussian channels. Boundary condition for the approximation is M≥4 and 0≤SNR≤30 dB

Display probability of symbol errors for MQAM on Rician fading channel based on MGF method

We present a new method for calculating the probability of error per symbol (Symbol Error Probability, SEP) of M-ary Quadrature Amplitude Modulation (MQAM) over a slow, flat, identically independently distributed Rician fading channels. Since fading is one of the major constraints in wireless communications, the diversity modulation technique is used for the efficient transfer of message signals. Exact analysis of error probability per symbol for MQAM, transmitted over Rician fading channels, is performed by N branches of diversity reception using maximum ratio of signal-to-noise power (maximal-ratio-combining, MRC), where the information in the channel on the receiver side is known. We also analyzed the performances of MQAM over Rician fading channels are here also analyzed. Approximate formula is used to represent SEP for MQAM transmitted over Gaussian channels. Boundary condition for the approximation is M≥4 and 0≤SNR≤30 dB