Wyniki wyszukiwania - BazTech

1

Effective nonlinear predictive and CTC-PID control of rigid manipulators

Tatjewski Piotr

Journal of Automation Mobile Robotics and Intelligent Systems

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2024

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Vol. 18, No. 2

1--16

EN

Effective nonlinear control of manipulators with dynamically coupled arms, like those with direct drives, is the subject of the paper. Model-based predictive control (MPC) algorithms with nonlinear state-space models and most recent disturbance attenuation technique are proposed. This technique makes controller design and online calculations simpler, avoiding necessity of dynamic modeling of disturbances or resorting to additional techniques like SMC. The core of the paper are computationally effective MPC-NPL (Nonlinear Prediction and Linearization) algorithms, where computations at every sample are divided into two parts: prediction of initial trajectories using nonlinear model, then optimization using simplified linearized model. For a comparison, a known CTC-PID algorithm, which is also model-based, is considered. It is applied in standard form and also proposed in more advanced CTC-PID2dof version. For all algorithms a comprehensive comparative simulation study is performed, for a direct drive manipulator under disturbances. Additional contribution of the paper is investigation of influence of sampling period and of computational delay time on performance of the algorithms, which is practically important when using model-based algorithms with fast sampling.

2

Examination of different models of troposphere delays in SBAS positioning in aerial navigation

Krasuski Kamil, Kirschenstein Małgorzata

Zeszyty Naukowe. Transport / Politechnika Śląska

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2023

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z. 118

123--137

EN

This paper presents the results of a study on the use of different tropospheric correction models in SBAS positioning for air navigation. The paper, in particular, determines the influence of the Saastamoinen troposphere and RTCAMOPS models on the determination of aircraft coordinates and mean coordinate errors in the SBAS positioning method. The study uses real kinematic data from a GPS navigation system recorded by an onboard GNSS satellite receiver as well as SBAS corrections. In the experiment, the authors include SBAS corrections from EGNOS and SDCM augmentation systems. The navigation calculations were performed using RTKLIB v.2.4.3 and Scilab 6.1.1 software. Based on the conducted research, it was found that the difference in aircraft coordinates using different troposphere models can reach up to ±2.14 m. Furthermore, the use of the RTCA-MOPS troposphere model improved the values of mean coordinate errors from 5 to 9% for the GPS+EGNOS solution and from 7 to 12% for the GPS+SDCM solution, respectively. The obtained computational findings confirm the validity of using the RTCA-MOPS troposphere model for SBAS positioning in aerial navigation.

3

Measurement of delay using travel time reliability statistics in an urban outer corridor

Reddy Kanala Teja Vinay Kumar, Challagulla Surya Prakash

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2022

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z. 114

143--154

EN

Unexpected delay on freeways is the prime cause of dissatisfaction in road users. Increasing traffic, adverse environmental conditions, accidents, time, season, location and many more factors influence travel time and cause delay. There is no direct method to estimate delay. It is calculated from trip time estimates. Thus, it is a very big challenge for transportation professionals to develop a model that accurately estimates the trip time for a trip at a particular time, by a specific mode of transport. Subsequently, the reliability of the delay calculated from those trip time estimates is often doubtful. Further, the measurement of delay using the trip time data is another big thing. This paper is a step toward measuring the delay in an accurate way using travel time reliability measures. The study was conducted on the two modes of public transportation (City bus and Auto) in an urban corridor of length 16.3 km, in Hyderabad city, India. In this study, a license plate survey was conducted for data collection, travel time-based statistical analysis was employed for estimation of trip time and by making use of travel time measures, the delay was measured. The approach was validated graphically to portray its accuracy.

4

Karakostas fixed point theorem and semilinear neutral differential equations with impulses and nonlocal conditions

Leiva Hugo, Riera Lenin, Lalvay Sebastián

Journal of Mathematics and Applications

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2022

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Vol. 45

107--128

EN

This paper is concerned with the existence and uniqueness of solutions for a semilinear neutral differential equation with impulses and nonlocal conditions. First, we assume that the nonlinear terms are locally Lipschitz, and to achieve the existence of solutions, Karakostas Fixed Point Theorem is applied. After that, under some additional conditions, the uniqueness is proved as well. Next, assuming some bound on the non-linear terms the global existence is proved by applying a generalization of Gronwall inequality for impulsive differential equations. Then, we suppose stronger hypotheses on the nonlinear functions, such as globally Lipschitz conditions, that allow us to appy Banach Fixed Point Theorem to prove the existence and uniqueness of solutions. Finally, we present an example as an application of our method.

5

Controllability of time varying semilinear non-instantaneous impulsive systems with delay, and nonlocal conditions

Cabada Dalia, Garcia Katherine, Guevara Cristi, Leiva Hugo

Archives of Control Sciences

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2022

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Vol. 32, No. 2

335--357

EN

In this paper we prove the exact controllability of a time varying semilinear system considering non-instantaneous impulses, delay, and nonlocal conditions occurring simultaneously. It is done by using the Rothe’s fixed point theorem together with some sub-linear conditions on the nonlinear term, the impulsive functions, and the function describing the nonlocal conditions. Furthermore, a control steering the semilinear system from an initial state to a final state is exhibited.

6

Open concurrent network communication methods in building distributed web applications

Buchwald Paweł, Dawid Aleksander

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2021

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Vol. 25, No 4

409--418

EN

The attractiveness of real-time multimedia communication as part of an e-learningplatform largely depends on the quality of the telecommunications infrastructure and on theservices that support the exchange of audiovisual data. The research subject of this workis communication between stationary and mobile devices using distributed services such asWeb Real-Time Communication (WebRTC) running in HTML5 compliant web browsers. Thetest connections were carried out in a peer-to-peer architecture over a local wireless WiFinetwork and a mobile network supporting the Long Term Evolution (LTE) standard fordata interchange. Several audiovisual sessions between two clients were analyzed for differentconnection scenarios. Parameters responsible for the transmission quality, such as delay, jitter,packet loss, or the speed of sending and receiving video frames were measured for each scenario.Open audiovisual communication system performance experiments were conducted under realoperating conditions. The obtained results indicated potential applications in the developmentof e-learning websites.

7

Analysis of The Effectiveness of Online Electronic Learning System Using Data Traffic Network Performance Management to Succeed Merdeka Learning : Merdeka Campus During the Covid-19 Pandemic

Budiyanto Setiyo, Silalahi Lukman Medriavin, Silaban Freddy Artadima, Sitorus Henry Binsar Hamonangan, Rochendi Agus Dendi, Ismail Mochamad Furqon

International Journal of Electronics and Telecommunications

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2021

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Vol. 67, No. 4

595--601

EN

The problems in the Covid-19 pandemic have a major influence on the field of education with the use of technology to support the teaching and learning process to facilitate students who do home learning activities. The proposed concept of freedom of learning is a more comprehensive concept such as portfolio and assignments such as group assignments, writings, and so on that are done in full online by adding additional features such as Teaching and Learning Activities and Assessment through information technology media. (E-Learning / Learning Management System). The method proposed in this research is the Peer Connection Queue (PCQ) method on mikrotik operating systems. PCQ method is a program to manage network traffic in Quality of Services (QoS). Bandwidth management methods. The hypothesis formulated is to create bandwidth management with PCQ so that bandwidth sharing is automatically and evenly distributed to multi clients. Therefore, in this research finally formulated into the goal of E-Learning effectiveness analysis using bandwidth management analysis method, which will be measured and analyzed in this research is throughput, delay, jitter, and packet loss. So that the final result of this research obtained the feasibility of the teaching and learning process that is carried out effectively.

8

Wpływ środowiska realizacji usługi WebRTC na jakość komunikacji

Rzemieniak Michał, Łubkowski Piotr

Elektronika : konstrukcje, technologie, zastosowania

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2021

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Vol. 62, nr 4

14--17

PL

Artykuł dotyczy testowania usługi WebRTC (Web Real Time Communication) w środowisku MiniNet. Przedstawiony został problem wpływu opóźnienia, przepustowości oraz poziomu strat pakietów na jakość komunikacji z wykorzystaniem usługi WebRTC. Przedstawione zostały aplikacje pozwalające na zmianę warunków panujących w sieci oraz aplikacja analizująca audio i wideo pod kątem jakości. Przybliżone zostały trzy scenariusze badań oraz wpływ zmieniających się parametrów w każdym z przypadków na jakość komunikacji.

EN

This article focused on testing the WebRTC (Web Real Time Communication) service in a MiniNet environment. The problem of how latency, bandwidth, and packet loss levels affect the quality of communication using the WebRTC service was shown. Applications that allow changing network conditions and an application that analyses audio and video for quality were presented. Three test scenarios and the impact of changing parameters in each case on the quality of communication are presented.

9

On controllability of fractional positive continuous-time linear systems with delay

Sikora Beata, Matlok Natalia

Archives of Control Sciences

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2021

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Vol. 31, No. 1

29--51

EN

In the paper positive fractional continuous-time linear systems are considered. Positive fractional systems without delays and positive fractional systems with a single delay in control are studied. New criteria for approximate and exact controllability of systems without delays as well as a relative controllability criterion of systems with delay are established and proved. Numerical examples are presented for different controllability criteria. A practical application is proposed.

10

Use of the EVM method for analysis of extending the construction project duration as a result of realization disturbances - case study

Starczyk-Kołbyk Anna, Kruszka Leopold

Archives of Civil Engineering

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2021

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Vol. 67, nr 3

373--393

EN

In pursuing numerous construction projects, investors and contractors regularly face construction delay problems, many of which are likely to have been avoidable. There is found that payment delays and project delays are the two most critical effects of risk factors of construction management. The paper presents the practical application of the Earned Value Management method, which was used to estimate the possible extension of the duration of construction works during which realization disturbances occurred on the example of selected construction investment. The realization disturbances are usually an inseparable element in the implementation of construction works. They are the result of, among others: additional works, changes or design defects, as well as a badly adopted logistics strategy regarding the supply of construction materials. Delays or increasing the total cost of investment is a problem often encountered in the implementation of construction investments, despite advanced construction technologies, including system technologies and proven tools supporting the management of the construction process. The EVM method is used to control investments. It allows you to control delays and acceleration of construction works as well as to estimate their cost and completion date. In the analyzed case it was used to determine the scale of delays arising in construction works and related effects with the specification of the participation of individual participants of the investment process for delays. This paper is a continuation and supplementation of the research presented in the article: “The influence of construction works disturbances on the EVM analysis outcomes - case study” [23].

PL

Realizując liczne projekty budowlane, inwestorzy i wykonawcy regularnie spotykają się z problemami dotyczącymi opóźnienia robót budowlanych, z których wielu prawdopodobnie można byłoby uniknąć. Stwierdzono, że opóźnienia w płatnościach i w realizacji inwestycji to dwa najbardziej krytyczne skutki czynników ryzyka związane z zarządzaniem budową. W artykule przedstawiono praktyczne zastosowanie metody Earned Value Management, która posłużyła do oszacowania możliwego wydłużenia czasu trwania robót budowlanych, podczas których wystąpiły zakłócenia budowlane na przykładzie wybranej inwestycji budowlanej. Nieodłącznym elementem realizacji robót budowlanych są zwykle zakłócenia budowlane. Są wynikiem m.in.: dodatkowych prac, zmian czy wad projektowych, a także źle przyjętej strategii logistycznej w zakresie dostaw materiałów budowlanych. Opóźnienia lub wzrost całkowitego kosztu inwestycji to problem często napotykany przy realizacji inwestycji budowlanych, pomimo zaawansowanych technologii budowlanych, w tym technologii systemowych i sprawdzonych narzędzi wspomagających zarządzanie procesem budowlanym. Do kontroli inwestycji stosowana jest metoda EVM. Pozwala kontrolować opóźnienia i przyspieszenie prac budowlanych oraz oszacować ich koszt i termin zakończenia. W analizowanym przypadku posłużył on do określenia skali opóźnień powstających w robotach budowlanych i związanych z nimi skutków. Niniejszy artykuł jest kontynuacją i uzupełnieniem badań przeprowadzonych na inwestycji budowlanej, przedstawionych w pracy: „Wpływ zakłóceń robót budowlanych na wyniki analizy EVM - studium przypadku” w 2020 r. [23].

11

Oscillatory criteria via linearization of half-linear second order delay differential equations

Baculikova Blanka, Dzurina Jozef

Opuscula Mathematica

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2020

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Vol. 40, no. 5

523--536

EN

In the paper, we study oscillation of the half-linear second order delay differential equations of the form [formula]. We introduce new monotonic properties of its nonoscillatory solutions and use them for linearization of considered equation which leads to new oscillatory criteria. The presented results essentially improve existing ones.

12

Performance evaluation of terminal airspace system safety, delay and predictability of Muritala Mohammed International Airport, Ikeja Lagos, Nigeria

Ejem Ejem Agwu, Ikeogu Vivian N., Okafor Chinenye L., Erumaka P. O.

Journal of Sustainable Development of Transport and Logistics

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2020

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Vol. 5, No. 2

62--72

EN

This paper outlines a multi-dimensional user-oriented performance metrics approach in evaluating the operation of the terminal airspace system to aid in the airport and airspace planning and decision making. Safety, delay and predictability metrics contribute to the analytical framework. From the findings, the occurrence of air incidence has a high severity level at departure, and arrival phases of flight, higher likelihood at the radar room and much of the incidences were as a result of faulty equipment and inherent absence of modern airspace infrastructure. Also, in Lagos terminal airspace, the number of incidences has no close correlation with the level of traffic complexity. Total schedule arrival delay ranges from 1-392 minutes representing an average of 7.8-17.9 minutes per aircraft that arrived Lagos airport at that period. Besides, the total approach contact time ranges from 1-57 minutes, translating to 4.6-7.1 minutes per aircraft. However, variability in arrival time of 1-5 minutes is common from published airline arrival scheduled time. In the same vein, the variability of 1-5 minutes is common from approach contact times of aircraft. These figures indicate sound arrival predictability signature for Lagos airport. Also, departure time variability above 30 minutes is familiar from the ATC clearance time for the various routes under study. However, there is about or more 25% variability of more than 15 minutes, and this indicates possible inconsistency of predicting departure times from the times ATC clearance was acquired. Above all, the predictability of departure times in Lagos airport is weak compared to those of the arrival. Taken by it, this may be a sign of airspace congestion or ATC deficiencies at the Lagos airport. This is an indication of the lack of users' confidence in Nigeria's air transport industry to deliver just-in-time service.

13

On the qualitative behavior of the solutions to second-order neutral delay differential equations

Chatzarakis George E., Santra Shyam S.

Fasciculi Mathematici

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2020

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nr 64

43--56

EN

In this paper, we study the qualitative behavior of the solutions to second-order neutral delay differential equations of the form (r(t) ((x(t) + p(t)x(τ (t)))′)γ)′ + q(t)f (x(σ(t))) = 0. Our main tool is Lebesgue’s dominated convergence theorem. Examples illustrating the applicability of the results are also given.

14

The influence of construction works disturbances on the EVM analysis outcomes - case study

Starczyk-Kołbyk Anna, Kruszka Leopold

Archives of Civil Engineering

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2020

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Vol. 66, nr 1

161--177

EN

The paper presents the problem of building disturbances, which are usually an inseparable element during the implementation of construction projects. They were classified, their causes and sides of the construction process responsible for their creation were identified on the basis of the analyzed construction investment. In addition, using the Earned Value Management method, the scale of delays arising in construction works and the related effects were determined. The important role of close cooperation and good communication between all participants of the construction process was emphasized, which would reduce the phenomenon of building disturbances, but also mitigate the negative effects of delays that have already occurred.

PL

W artykule dokonano szczegółowej analizy procesu inwestycyjnego na etapie wykonawstwa wybranej współczesnej inwestycji kubaturowej finansowanej ze środków budżetowych. Przedstawiono również problem zakłóceń budowlanych, które są z reguły nieodłacznym elementem podczas realizacji przedsięwzięć budowlanych oraz dokonano ich klasyfikacji. Po przeprowadzeniu szczegółowej analizy przedmiotowego procesu budowlanego zidentyfikowano występujące zakłócenia budowlane na badanej inwestycji obejmujące łącznie 1165 dni realizowanego okresu wykonawstwa.

15

Badanie wpływu mikroemulsji wodno-paliwowych na okres zwłoki samozapłonu w silniku o zapłonie samoczynnym

Lotko Wincenty, Longwic Rafał, Górska Milena

Przemysł Chemiczny

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2019

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T. 98, nr 6

924--927

PL

Przedstawiono wyniki badań dotyczących wpływu wody zdyspergowanej w mikroemulsji paliwowej na zmianę okresu jej samozapłonu. Określono wybrane właściwości fizyczno-chemiczne oleju napędowego (ON) oraz testowanych mikroemulsji zawierających 4 lub 8% mas. wody destylowanej. Paliwa te wykorzystano do zasilenia silnika badawczego firmy AVL. Wyniki potwierdziły, że obydwie testowane mikroemulsje wodno-paliwowe charakteryzowały się mniejszą skłonnością do samozapłonu niż ON.

EN

Gas oil and its aq. microemulsions (4 and 8% by mass) were tested as fuel in diesel engine. Both tested microemulsions had lower ability for self-ignition than the gas oil. Selected phys.-chem. properties of tested fuels were detd.

16

Oscillatory results for second-order noncanonical delay differential equations

Dzurina Jozef, Jadlovska Irena, Stavroulakis Ioannis P.

Opuscula Mathematica

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2019

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Vol. 39, no. 4

483--495

EN

The main purpose of this paper is to improve recent oscillation results for the second-order half-linear delay differential equation [formula] under the condition [formula]. Our approach is essentially based on establishing sharper estimates for positive solutions of the studied equation than those used in known works. Two examples illustrating the results are given.

17

Współpraca w procesie budowlanym szansą dla producentów

Idźkowski Franciszek, Wieczorek Justyna

Materiały Budowlane

|

2019

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nr 6

79--81

18

Third order singularly perturbed delay differential equation of reaction diffusion type with integral boundary condition

Sekar Elango, Tamilselvan Ayyadurai

Journal of Applied Mathematics and Computational Mechanics

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2019

|

Vol. 18, nr 2

99--110

EN

A class of third order singularly perturbed delay differential equations of reaction diffusion type with an integral boundary condition is considered. A numerical method based on a finite difference scheme on a Shishkin mesh is presented. The method suggested is of almost first order convergent. An error estimate is derived in the discrete norm. Numerical examples are presented, which validate the theoretical estimates.

19

Faktory opóźnień [w procesie budowy]

Leśniak Agnieszka, Piskorz Grzegorz

Builder

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2019

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R.23, nr 2

26--28

EN

Identification and rank of delay factors in construction projects depending on the project delivery system. The implementation of construction projects depends on many unpredictable factors, which can cause delays in construction works. The article proposes classification of the validity of delay depending on the project delivery system. Two of them were considered: the traditional system (Design – Bid – Build), where the design stage is separated from the construction stage and the design and build (Design & Build), which consists in entrusting design works and carrying out works to one contractor. The order of validity is based on results of research carried out among participants of the construction project.

20

Modelling delays in bridge construction projects based on the logit and probit regression

Leśniak A., Juszczyk M., Piskorz G.

Archives of Civil Engineering

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2019

|

Vol. 65, nr 2

107--120

EN

Construction projects, even exemplarily planned and organized, bear a risk of unforeseen events and problems which can result in completion of the works after the deadline, that is delays. The construction of bridges is an inseparable part of road and rail projects and construction and expansion of the transport network. The paper aims at finding a relationship between the independent variables characterizing bridge projects and the delays during their implementation. Two alternative models were proposed to solve the problem: logit and probit. The data set comprising road and rail bridges built in Poland in the last 12 years (2005 – 2017) was used to build the models. The evaluation, quality and accuracy parameters of proposed models were determined in the final part of the paper.

PL

Pomyślne zakończenie przedsięwzięcia budowlanego oznacza terminowe ukończenie budowy w ramach założonych kosztów i planowanej jakości oraz spełnieniem oczekiwań inwestora. Istotny wpływ na powodzenie inwestycji drogowych czy kolejowych ma realizacja obiektów mostowych. Są one niezbędne dla zapewnienia połączeń i pokonania przeszkód w terenie, a ich obecność gwarantuje ciągłość tras komunikacyjnych. Obiekty mostowe stanowią newralgiczne punkty, będąc nierzadko kamieniami milowymi dla wykonawcy robót. Celem artykułu, jest rozwiązanie problemu klasyfikacyjnego dotyczącego opóźnień w realizacji obiektów mostowych. Istotą analizy jest poszukiwanie związku między zmiennymi niezależnymi charakteryzującymi przedsięwzięcia obejmujące budowę obiektów mostowych, a faktem wystąpienia opóźnienia podczas ich realizacji. W pracy poszukiwano modelu dwumianowego, w którym zmienna objaśniania Y jest kwantyfikowana za pomocą wartości dychotomicznej (przyjmującej jedną z dwóch możliwych wartości). Założono, że zmienna Y przyjmowała dwa możliwe warianty określone za pomocą kodów - etykiet: „TAK” odpowiadającego opóźnieniu przedsięwzięcia mostowego, „NIE” oznaczającego brak opóźnienia przedsięwzięcia mostowego (kody należy utożsamiać odpowiednio z wartościami 1 i 0). W artykule zaproponowano rozwiązanie problemu z wykorzystaniem dwu alternatywnych modeli - logitowego i probitowego. W analizie wykorzystano dane zebrane w ramach badań własnych obejmujące parametry realizacji przedsięwzięć mostowych i parametry obiektów mostowych, a także wielkość opóźnienia (jeżeli wystąpiło). W wyniku przeprowadzonych badań zgromadzono dane dotyczące 169 obiektów mostowych, w tym 48 obiektów, w których nie wystąpiły opóźnienia i 121, w których wystąpiły opóźnienia. W analizie wykorzystano dane przedstawiające 109 przypadków. W toku pracy badawczej zbudowano dwa alternatywne modele: logitowy i probitowy oraz przeprowadzono analizę wyników. Wyniki uzyskane dla obu modeli były zbliżone, jednak nieco lepsze wyniki klasyfikacji uzyskano w przypadku modelu logitowego, który zidentyfikował poprawnie 75% przypadków. Procent poprawności klasyfikacji tego modelu był lepszy w klasie „1” oznaczającej wystąpienie opóźnienia (84%), niż w klasie „0” brak opóźnienia (65%). Autorzy zwracają uwagę, iż zaproponowane modele pozwalają na klasyfikacje zmiennej objaśnianej Y, która jest kwantyfikowana za pomocą wartości dychotomicznej. W planach badawczych autorów jest podjęcie próby klasyfikacji wielkości opóźnień, nie tylko samego faktu jego wystąpienia. Takie założenie wymaga zatasowania innych narzędzi np. sztucznych sieci neuronowych.