PREDICTION OF FINE PARTICULATE MATTER IN LOW-EMISSION ZONES USING A MODIFIED NUMERICAL METHOD FOR A SYSTEM OF ORDINARY DIFFERENTIAL EQUATIONS

Currently, many European cities have severely exceeded the EU air quality standards and are struggling with high concentrations of fine particulate matter PM10 and PM2.5 in the air, with road transport often being one of the major polluters. One of the forms for correction of the problem that many cities in the EU are currently using is the construction of low-emission zones. For the prediction of PM10 and PM2.5, a modified numerical method for a system of ordinary differential equations has been proposed. In the right part of this system, in addition to the main trend and the periodicity of PM10 and PM2.5, their correlation is taken into account. Against the background of the best solution obtained, a forecast is made for the emission levels in a period of one week in the town of Ruse

INTELLIGENT SYSTEM FOR IMPROVED SAFETY OF PEDESTRIAN TRAFFIC LIGHTS

The high concentration of vehicles and pedestrians at traffic lights makes them a common place for road accidents to occur. The main reason for them is the behavior of vehicle drivers and pedestrians, who often violate the traffic law because of incorrect judgments. This study investigates a special type of traffic lights, which are located on places without roads intersection. In the present study, a concept for improving the safety of such traffic lights is suggested. The method suggests a novel algorithm for the detection of pedestrians, based on image processing and a background pattern. The concept of the detection system makes it applicable in different climatic conditions, such as rain, snow, dust, etc., and offers many advantages over the current situation in Bulgaria. The intelligent system only detects pedestrians in the waiting zones, in order to optimize the traffic problems, such as traffic delays, use by disabled people, protection against troublesome users, etc

Methodology for expert evaluation of multimodal cargo transportation routes

The multimodal transportation of transit cargo is suitable for implementation through Bulgaria in the East-Northwest direction through the sea and river ports of the country as an alternative to the Romanian and Greek routes. Among the multimodal routes with a land leg through Bulgaria used and known so far, those via two seaports (Burgas and Varna) and three river ports (Ruse, Svishtov and Vidin) are most suitable. An expert evaluation methodology for selection of the most appropriate route is developed, including the Delphi method. A survey was conducted among 11 highly ranked and internationally recognized Bulgarian experts, known for their exceptional experience in the field of freight forwarding and international cargo transportation through Bulgaria. The results of the study show that the most suitable route for transit transportation is through the ports of Varna and Ruse with intermediate road haulage

Planning and modeling of the time for acceptance and stay of vehicles at the loading and discharging points

When delivering goods in the warehouses of enterprises, courier and forwarding companies, and for logistics operators, loading and unloading is usually done manually or mechanically. On the other hand, the load can first be placed on the ground next to the vehicle and then accepted in the pile, or a ramp can be used so that it can be delivered directly to the warehouse or vice versa. When there is a ramp, the loading and discharging activity is performed faster and it is much easier. When there are many vehicles serviced on ramps, it is necessary to have a free ramp available. This is often not the case when the warehouse has more ramps and a large exchange of goods. In this case, a time schedule is usually made for the reception and handling of vehicles, which is communicated to carriers and drivers so that there is no unnecessary downtime of vehicles and overloading of points with ramps. There are cases in which the established organization of work cannot be performed due to various force majeure or other reasons, such as delays at border crossings, bans on passing through certain sections, change in the working hours of warehouses, pandemic and other reasons. The vehicles then arrive at the checkpoints at a time that is different from their schedule and have to wait to be serviced. Waiting at the unloading points makes drivers nervous and they become dissatisfied with the working conditions. In this respect, a solution has been proposed based on the working hours and occupancy of the loading and discharging point and the time of arrival of the vehicles at the point, and how to receive the vehicles so that the waiting time between them is the shortest. For this purpose, a partially integer linear optimization model has been created in Matlab, which provides a valid plan with the shortest waiting times for all vehicles. Simulations have been made for different numbers of ramps and vehicles. The results show that the model is suitable for pre-creating a valid plan for the operation of the vehicle warehouse, if any, with a minimum waiting time