Scheduling of repetitive construction processes with concurrent work of similarly specialized crews

The highest degree of construction works harmonization can be achieved when planning a repetitive project with processes replicated many times in work zones of identical size. In practice, structural considerations affect the way of dividing the object under construction into zones differing in terms of scope and quantity of works. Due to this fact, individual processes are being allotted to different non-identical zones. Most methods intended for scheduling repetitive processes were developed with the assumption that the work zones are identical and that a particular process cannot be concurrently conducted. To address this gap, the authors put forward a mathematical model of the problem of scheduling of repetitive processes that are repeated in different work zones with the following assumption: several crews of the same type are available, thus particular process can run simultaneously in different locations. The aim of optimization is minimizing the idle time of all crews under the constraint of not exceeding the contractual project duration. The proposed mixed binary linear programming model can be solved using software available in the market or developed into a dedicated system to support decisions. To illustrate the benefits of the model, an example of scheduling interior finishing works was provided

Using soft precedence relations for reduction of the construction project duration

Current network techniques used for project scheduling presume that there is only one logical sequence of activities. However, in reality, the precedence logic of activities is not necessarily unchangeable. There are two types of relations between activities: fixed (hard) and soft. Current scheduling methods do not differentiate between these two types of relations and require a planner to choose one particular logical sequence based on some assumptions. The paper presents a model that allows for “weakening” the links between activities, i.e. that permits concurrent execution of activities or reversing their order, but this may require additional resource-consuming works or expenditures. The model involves two subtypes of soft logic: REVERSED and CANCELED to represent the soft relations between activities. Its mathematical form is a mixed linear integer programming model of minimizing the project duration without exceeding the allowed budget. The paper presents an example of practical application of the method to scheduling interior finishing works. The results support the argument that using soft logic relations between construction activities provides more flexibility in reducing project duration, activities timing and resource allocation

Reducing renewable resource demand fluctuation using soft precedence relations in project scheduling

Renewable resource levelling is the core of the scheduling process. A perfect schedule ensures that resource supply corresponds to the demand at every unit of project time. A classic approach to resource levelling in schedules with predefined project completion dates consists in manipulating processes start dates. Resource deployment can be also improved by considering alternative construction processes execution modes with various crew formations, and by allowing activities to be split. There are other possibilities: in many practical cases, the activities’ precedence logic predefined in the network model can be changed with no harm to the project outcome. Within the structure of the project network model, some precedence relations between activities would definitely be of fixed (hard) character, whereas some might allow the activities to be executed at the same time or arranged in a variety of logical sequences. The authors use soft precedence relations that let the processes run in reversed order or that can be cancelled, in search for improved resource usage profiles. The benefits of scheduling with soft precedence relations are demonstrated by an example

The Design of the Telemetric System for Recording Operating Parameters of Electric Vehicles

The article presents the prototype of the original telemetric system developed as a part of Warsaw University of Technology Rector's Grant by Science Club of Electrical Engineering in Transport Systems (KNEST) together with the Faculty of Transport. The system was designed for remote monitoring and recording of electric vehicle’s operating parameters. Under the project electric go-kart was a technology demonstrator for which velocity, current, voltage, temperature and GPS coordinates were recorded. Data are transferred in real-time, what allows to monitor all parameters of the electric vehicle on-line. The article describes functional requirements for the developed system and the elements used, including sensors of signals. The authors present steps of transfer of data acquired from the vehicle until their visualization at the remote computer through the developed application. The advantages of the system are long range wireless connectivity, low price and wide upgrade possibilities. The tests performed have shown the correct functioning of the system and its compliance with the assumptions

Analysis of results of emission parameters of advertising media in field conditions

The lighting parameters of advertising media observed from the road leading drivers are one of the basic factors which should be taken into account in the process of determining the influence of the carrier on the risk related to the possibility of a road event. As a result, exceeding the permissible parameters may lead to disturbance of the vision process or distraction from the driver’s primary objective, which is to observe the road situation. The article presents the results of tests of lighting and geometric parameters carried out on a large number of advertising media located in the vicinity of Polish roads. The study was conducted at night, using an original research procedure. Observation of advertising media from the driver’s position is included. The final result of the work is information about the actual levels of lighting parameters generated by a large group of advertising media of different character of light beam emission (broken down into defined emission groups A - D), which can be observed from the driver's position

Construction of a Measurement System with GPS RTK for Operational Control of Street Lighting

Street lighting should realise normative illuminance levels throughout the roadway. The determination of the illuminance level of a road requires the use of a measurement technique based on classic point measurements at a specific grid of measurement points. Classical stationary measurements using the method indicated in the prescriptive requirements are time-consuming and labor-intensive. The authors of the article have presented a concept of a measurement system that could be used to partially automate road lighting measurements and increase their universality. The proposed measurement system uses the simultaneous measurement of illuminance values from lux meters located on the roof of the vehicle. The measurement is carried out while the vehicle is driving on a lit road, and the illuminance values are localized using a global GPS satellite location system equipped with RTK corrections. The use of GPS RTK localization data corrections allowed the measurement results to be unambiguously assigned to post-measurement fields. On the basis of the collected measurement data, with the use of terrain maps, it is possible to determine in detail the illuminance parameters on the surveyed road sections. The paper presents the construction of a measurement system for the mobile measurement of street lighting intensity using a GPS RTK receiver, along with verification of its correct operation. The correctness of the system’s operation was confirmed on the basis of the Measurement System Analysis (MSA) method. The calculations performed confirmed an R&R result of 11.14%. The proposed solution allows data on the lighting parameters of the surveyed road section to be obtained in a quick and repeatable manner. As a result, it is possible to make a quick assessment of the street lighting condition of the entire road section. The proposed system has been verified under field conditions and the repeatability of the results obtained has been confirmed

Analysis of results of emission parameters of advertising media in field conditions

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Evaluation of Street Lighting Efficiency Using a Mobile Measurement System

The issue concerns the initial stage of work on a method for performing a rapid assessment of the energy efficiency and illuminance of a street lighting installation. The proposed method is based on simultaneous measurement of illuminance from three lux meters placed on the roof of the vehicle. The data are acquired in road traffic, while the vehicle is driving. The proposed solution will allow in the future to quickly and reproducibly obtain data about the lighting parameters of the studied road section. The illumination values are localised using Global Navigation Satellite System (GNSS). Based on the collected measurement data, with the use of terrain maps, geographic information system (GIS) data and installation design documentation, it will be possible to determine in detail the parameters of energy efficiency indicators for a selected section of the street for the entire street according to the EN13201-5 standard. Preliminary tests were conducted on a section of about one kilometer of street illuminated in class C3. Detailed measurements reveal high variation of obtained energy indicators DP and DE for each road section. The reason for this condition is the variation of power, installation geometry and the presence of obstacles to light

The Design of the Telemetric System for Recording Operating Parameters of Electric Vehicles

The article presents the prototype of the original telemetric system developed as a part of Warsaw University of Technology Rector's Grant by Science Club of Electrical Engineering in Transport Systems (KNEST) together with the Faculty of Transport. The system was designed for remote monitoring and recording of electric vehicle’s operating parameters. Under the project electric go-kart was a technology demonstrator for which velocity, current, voltage, temperature and GPS coordinates were recorded. Data are transferred in real-time, what allows to monitor all parameters of the electric vehicle on-line. The article describes functional requirements for the developed system and the elements used, including sensors of signals. The authors present steps of transfer of data acquired from the vehicle until their visualization at the remote computer through the developed application. The advantages of the system are long range wireless connectivity, low price and wide upgrade possibilities. The tests performed have shown the correct functioning of the system and its compliance with the assumptions