29 research outputs found
Non-invasive genetic study and population monitoring of the brown bear (Ursus arctos) (Mammalia: Ursidae) in Kastoria region - Greece
No full textTsaparis, Dimitris, Karaiskou, Nikoleta, Mertzanis, Yorgos, Triantafyllidis, Alexander (2014): Non-invasive genetic study and population monitoring of the brown bear (Ursus arctos) (Mammalia: Ursidae) in Kastoria region - Greece. Journal of Natural History 49 (5): 393-410, DOI: 10.1080/00222933.2013.87799
Figure 1 in Non-invasive genetic study and population monitoring of the brown bear (Ursus arctos) (Mammalia: Ursidae) in Kastoria region - Greece
No full textFigure 1. The study area in Kastoria region and capture locations (red dots) for the 75 living bears.Published as part of Tsaparis, Dimitris, Karaiskou, Nikoleta, Mertzanis, Yorgos & Triantafyllidis, Alexander, 2014, Non-invasive genetic study and population monitoring of the brown bear (Ursus arctos) (Mammalia: Ursidae) in Kastoria region - Greece, pp. 393-410 in Journal of Natural History 49 (5) on page 396, DOI: 10.1080/00222933.2013.877992, http://zenodo.org/record/400411
Figure 2 in Non-invasive genetic study and population monitoring of the brown bear (Ursus arctos) (Mammalia: Ursidae) in Kastoria region - Greece
No full textFigure 2. (A) Means of estimated LnP (Data) and standard deviations for K = 1 to K = 5. (B) Factorial correspondence analysis plot of multilocus genotypes for 82 brown bear individuals identified in the present study.Published as part of <i>Tsaparis, Dimitris, Karaiskou, Nikoleta, Mertzanis, Yorgos & Triantafyllidis, Alexander, 2014, Non-invasive genetic study and population monitoring of the brown bear (Ursus arctos) (Mammalia: Ursidae) in Kastoria region - Greece, pp. 393-410 in Journal of Natural History 49 (5)</i> on page 402, DOI: 10.1080/00222933.2013.877992, <a href="http://zenodo.org/record/4004112">http://zenodo.org/record/4004112</a>
Using object-specific frequency information from labeled data to improve a CNN’s robustness to adversarial attacks
No full textConvolutional Neural Networks are particularly vulnerable to attacks that manipulate their data, which are usually called adversarial attacks. In this paper, a method of filtering images using the Fast Fourier Transform is explored, along with its potential to be used as a defense mechanism to such attacks. The main contribution that differs from other methods that use the Fourier Transform as a filtering element in neural networks is the use of labeled data to determine how to filter the pictures. This paper concludes that, while the filtering proposed is hardly better than a simple low-pass filter, it still manages to improve resistance to adversarial attacks with a minimal drop in the standard accuracy of the network.CSE3000 Research ProjectComputer Science and Engineerin
A note on capital utilization and international trade
No full text© The Author 2017. Published by Oxford University Press on behalf of the Cambridge Political Economy Society. This article integrates the analysis of durable capital utilization in the theory of international trade. Variations in capital utilization are analytically accounted for in the form of shift work. Accordingly, producers normally choose the combination of the system of operation of durable capital and labor input that minimizes costs. The choice of the system of operation of durable capital is shown to affect the terms of trade and thereby the structure of production in such a way as to make it desirable, following changes in income distribution, to adopt a new combination of capital utilization and labor input. On certain simplifying assumptions associated with the properties of Sraffa models, linear technologies, long period positions, and steady growth, these possibilities affect, in an unpredetermined manner, the inducement to trade and the direction and extent of the resulting specialization. The results are independent of any differences in the technical conditions of production of the trading countries or the existence of heterogeneous capital goods
Optimizing the pump schedule of water distribution systems using a deep learning meta-model: To what extent can algorithm unrolling optimize the pump schedule of an urban water distribution system?
No full textThis thesis investigates the integration of algorithm unrolling and genetic algorithms (GA) for optimizing pump scheduling in water distribution systems (WDS), a critical component for ensuring energy-efficient water delivery. In the context of modern civilization’s reliance on clean, affordable water for diverse uses, the operation of a WDS, particularly through energy-intensive pumps, presents significant challenges. Traditional optimization techniques often resort to hydraulic solvers like EPANET, which, while accurate, are computationally intensive for large-scale applications. Our methodology introduces a meta-model based on algorithm unrolling, building upon prior work and extending it to address pump scheduling with a multi-objective function focusing on both cost and energy efficiency. This approach significantly reduces the computational load, offering a faster alternative to EPANET while maintaining considerable accuracy. The meta-model demonstrated promising results in the Fossolo network, achieving comparable schedules 20 times faster than traditional methods. However, its applicability to more complex networks and its ability to capture detailed system behaviors are limited, highlighting the need for further enhancements in model stability and reproducibility. Despite these limitations, the study emphasizes the potential of meta-models as a complementary tool to traditional methods, especially in scenarios requiring rapid decision-making under computational constraints. This research contributes to the broader field of water utility management, offering insights into more sustainable and efficient operation strategies.Water Managemen
Towards a semantic framework for wildlife modeling
No full textIn this paper we present work in progress for developing a semantic modeling system for wildlife
monitoring, management and conservation. Based on a Greek NGO experience in large carnivores
conservation in the mountain ecosystems of northern Greece, we present a generic architecture for
wildlife information fusion, sharing and reuse. Our framework employs ontologies for representing
the key domain concepts and their relationships, and applies them for integrating sensory
information from GPS/GSM animal tracking devices, along with other field data and habitat
suitability models.http://enviroinfo.eu/sites/default/files/pdfs/vol8514/0287.pd
Exploring 15 years of brown bear (Ursus arctos)-vehicle collisions in northwestern Greece
No full textRoad networks provide several benefits to human societies; however, they are also one of the major drivers of fragmentation and habitat degradation. Their negative effects include wildlife-vehicle collisions which are associated with increased barrier effects, restricted gene flow, and increased local extinction risk. Large carnivores, such as the brown bear (Ursus arctos), are vulnerable to road mortality while they also put human safety at risk in every collision. We recorded approximately 100 bear-vehicle collisions during the last 15 years (2005–2020) in northwestern Greece and identified common aspects for collisions, i.e., spatial, or temporal segregation of collision events, road features, and age or sex of the involved animals. We recorded collisions in both the core distribution area of brown bears, as well as at the periphery, where few individuals, mostly males, disperse. According to our findings, there are four collision hotspots which include ca. 60% of total collisions. Bear-vehicle collisions occurred mostly in periods of increased animal mobility, under poor light conditions and low visibility. In most cases, we deem that a collision was unavoidable at the time of animal detection, because the driver could not have reacted in time to avoid it. Appropriate fencing, in combination with the retention of safe passages for the animals, can minimize collisions. Therefore, such mitigation measures, wildlife warning signs and other collision prevention systems, such as animal detection systems, should be adopted to decrease the number of bear-vehicle collisions and improve road safety
Corporate Governance Rating and Family Firms: The Greek Case
No full textCorporate governance (CG) studies have mostly focused on highly dispersed corporations. However, there is an important need for research exploring the governance structure of family-owned firms. The main characteristics that distinguish the family firm from the other types of corporations are the presence of one or more controlling family and the involvement of the owners in the management. Family firm is the most common form of business in Greece. Hence, the governance structures and the performance of the family firms affect the growth opportunities of the capital market. The aim of the paper is to explore the main aspects of CG of family-owned listed companies in Greece. For this purpose, we apply a specific CG rating methodology, using five core CG criteria to distinguish family from non-family firms: shareholders' rights and obligations; transparency, disclosure of information and auditing; board of directors; CEO and executive management and corporate social responsibility and corporate governance commitment. The overall research objective of the study is to develop a CG rating methodology on the current state of corporate governance in Greece. Each firm is rated among the 120 total number of companies (both family-owned and widely- held). The results disclose the potential strengths and weaknesses of the existing corporate governance framework of the family-owned firms and provide specific policy recommendations.family firms, corporate governance rating, Greece
Contribution in the investigation of stopping sight distance in 3-dimensional space
No full textThe issue of road safety assessment has always been the case in road design. Sight distance is a measurable parameter which can be a key criterion in road safety assessment considering the human factor. Stopping Sight Distance (SSD) adequacy, namely ensuring sufficient free length in the front view of the driver in order for him to be able to perceive and react to dangerous situations, is a basic requirement for the safety of traffic flow. The required SSD, which relates to the ability to bring the vehicle to a halt, depends on road geometry, the driver’s perception – reaction ability and the vehicle’s dynamic features, while it is the basis for selecting critical geometric parameters. The available SSD mainly depends on road environment and road geometry. Therefore, it is important that SSD adequacy investigation is performed across the entire road, in relation with the features of the road environment.The objective of this Doctoral Thesis is the development of a methodology for SSD adequacy investigation, considering concurrently the factors which impact a road’s provided safety, namely the road geometry, the vehicle and the user – driver. The proposed methodology includes considering the involved parameters in three-dimensional space and the identification of areas where the sightline between the driver’s eyes and an obstacle is interrupted by an obstacle which is positioned in such way so that the road’s security is compromised. More specifically, the proposed methodology relates to the following:•As far as the road’s geometry is concerned, the influence of roadside features is investigated, in addition to the three-dimensional consideration of the design parameters.•Regarding the vehicle, the influence of its dynamic features during its movement along a curved path is taken into account and, therefore, a more accurate simulation of the braking process in a three-dimensional rolling surface is given, since this is related directly to the road’s geometry.•The presence of the user – driver is taken into account in the sense of the ability to perceive the alignment from the driving position, through the visualisation of the road and the surrounding environment.In the current design practice of assessing visibility conditions, the road’s geometry is not fully taken into account, given that consideration of the road environment is rather simplified and fragmentary, in a two-dimensional space. SSD adequacy investigation is mainly based on two-dimensional models, which means that check is performed independently on the horizontal alignment and the longitudinal profile. The models of assessing SSD adequacy and determining critical geometric quantities to be adopted in the design of horizontal alignment and longitudinal profile are similar and basically only differ in the selection of their parameters. Consequently, there are parameters which are not taken into consideration and their effect can be crucial in the safety provided.More specifically, during the assessment based on the horizontal alignment, critical parameters such as variable longitudinal slope due to the presence of a crest or sag curve, and the heights of the driver’s eyes and the obstacle are ignored. Similarly, assessment based on the longitudinal profile is performed assuming that the horizontal alignment is straight, which obviously applies to individual cases, while the influence of the transverse slope of the roadway is also important. Additionally, vehicles are regarded as material points without taking into account their dynamic features, thus the correlation of their parameters with road safety is empirical. Therefore, the proposals for ensuring SSD adequacy, through the selection of critical parameters for the combined design of horizontal and vertical geometry, are mainly given in the form of empirical recommendations, with insufficient scientific documentation.In addition, guidelines for road design provide mathematical formulae for calculating SSD in simple independent horizontal and vertical alignments, with the use of simplifying assumptions which, however, not fully correspond to reality, with chances of providing false results. For more complex cases, the use of graphical or three-dimensional methods is recommended, but no further description is given. Moreover, it is proposed that perspective images of the road can be created in certain positions and the need of three-dimensional analysis is emphasised.Therefore, the current two-dimensional design methods may overestimate or underestimate available sight distance, leading to unnecessary increase in costs or, even worse, to the existence of dangerous sections along a road. In such cases, the effects can be detrimental to the cost and efficiency of existing and planned roads, given that excessive modifications and/or areas with speed limits less than those truly required are rather inevitable, which may not meet the driver’s expectations and compromise design consistency.Given that SSD adequacy is of fundamental importance for the safety of any road, extensive research has been carried out, in determining both the required and available SSD. The proposed methods for determining sight distance can be divided into two-dimensional (separate analysis of horizontal and vertical alignment) and three-dimensional (road is considered directly in space), as well as into graphical and analytical. As far as two-dimensional approach is concerned, methods aiming at a more precise approach of SSD assessment, in comparison with the existing road design guidelines, have been published. Furthermore, various three-dimensional methods have been developed for SSD adequacy investigation, which take into account the interaction of the elements of horizontal and vertical geometry, as well as the road environment, and thus allow for a more realistic and accurate analysis. According to the two-dimensional method, the available SSD is calculated by considering exclusively either the horizontal alignment or the longitudinal profile. The problem arising in cases of independent consideration of either the horizontal or the vertical profile, is the possible inaccuracy of the results of calculation, since the interaction between profiles is not taken into account in the driver’s perception of the road environment, especially in cases of simultaneous existence of curvature. An improvement to this approach is SSD calculation on both profiles and the adoption of the minimum value in each position of the road, as a conservative estimate. However, the results are still approximate. Therefore, two-dimensional design can overestimate or underestimate SSD available, with negative effects on the economy and, especially, on the safety of the road.As far as three-dimensional graphical methods are concerned, they represent an alternative way for SSD analysis and allow for a correct approach to the SSD problem. However, graphical methods prove to be time consuming, since they do not offer an automation of visibility analysis and, hence, they are not considered effective if used in large scale road projects.Therefore, it is obvious that three-dimensional analysis, with the use of analytical models, allows for the most appropriate approach to the issue of visibility, where the road is considered as a single entity in space, so that all of its features can be simultaneously taken into account. Additionally, the creation of perspective images from the driver’s position, along the road, is a useful tool for checking the alignment’s quality and for detecting problematic sections in terms of visibility.The proposed three-dimensional methods of SSD assessment allow for an accurate simulation of a compound road environment and, hence, the accurate determination of the driver’s actual field of vision. However, most of these studies focus on the optimisation of the available SSD either by introducing new algorithms or by proposing certain combinations of design parameters, ignoring in many cases some of the elements of the road and its environment, which significantly affect visibility levels. Furthermore, none of these approaches has suggested a comprehensive methodology to concurrently simulate from a three-dimensional perspective both the cross-section elements and the vehicle dynamics in space during emergency braking conditions. Finally, another key deficiency of the related three-dimensional methods is the lack of analysis of the design elements limiting the available SSD in each case, which would allow the designer to immediately perform the necessary adjustments to further improve the end result of the alignment.The proposed three-dimensional analytical method has been developed in order to create a comprehensive visibility analysis tool, which will provide fast and accurate results, minimising the deficiencies identified both in relevant methods and in current practice. This method is incorporated in the “H12” road design software, which, similarly, has been developed by the author of the present Doctoral Thesis and provides the ability to perform all tasks related to the geometric design of a road. The proposed methodology is summarised as follows:•A three-dimensional model of the road and the roadside area is created. With the use of “roadlines” it is possible for the driver’s eye and the obstacle to be placed laterally and at any distance from the road axis, as well as for visibility levels to be specified, due to the existence of road components and equipment, which constitute potential sight obstacles. Next, a total number of road cross-sections is produced, depending on the calculations step which is defined. With the use of triangulation method, a network of triangles is created among the cross-sections, representing the road and formations surfaces, as well as the Digital Terrain Model of the area. The final road and roadside model is derived by the superimposition of the road model to the terrain model.•Demanded SSD is specified. Demanded SSD calculation is based on an improved approach to the current practice, where both horizontal and vertical curvature are considered, by the inclusion of the influence of transversal and longitudinal friction, as well as the variable inclination along crest and sag curves.•Available SSD is specified. Available SSD calculation is based on the identification of potential points of intersection between the sightlines amid the driver’s eye and the obstacle, and the triangles representing road and roadside surfaces. The equations of triangles and sightlines, as well as their points of intersection, are determined using analytical geometry.•SSD adequacy assessment is performed through an iterative algorithm, so as to identify areas along the road where sightlines are interrupted by an obstacle and their length is less than the required SSD. The precision of calculations depends on the calculations step, namely the distance between two consecutive points along the road under consideration.•The results of analysis are exported in the form of diagrams displaying available and required SSD, namely:Demanded SSD diagram.Available SSD diagram, as it has been calculated using the three-dimensional analytical method.Available SSD diagram, as it has been calculated based on the longitudinal profile of the road (two-dimensional method).Three-dimensional extension of the visibility diagram, through which the visibility conditions on the remaining part of the road are described, for each point of the road.•Perspective images from the driver’s position are created, along the road, according to the parameters entered.With the use of the H12 software, the proposed methodology is applied to two examples of SSD analysis, in order, firstly, to examine to what extent the use of marginal proposed values of design parameters, according to road design guidelines, provides SSD adequacy and, secondly, to compare the corresponding results obtained by applying the two-dimensional method (where only longitudinal profile is taken into account) and the proposed three-dimensional analytical method. Two theoretical alignments are considered, with different typical cross-sections, whose horizontal alignment and longitudinal profile are of the same form, so that every possible combination of simultaneous curvature appears. Marginally allowable values of the design parameters are used, according to the Greek and German road design guidelines.The study of visibility diagrams shows that, in divided roads, the results of the two alternative methods vary greatly, although it is shown via both of them that the available SSD is significantly restricted in areas with crest vertical curves. In undivided roads, the corresponding results are similar in cases of crest vertical curves, where it is shown that available SSD is significantly restricted, and differ in cases of sag vertical curves, where, according to the three-dimensional method, available SSD is significantly restricted.These results confirm the conclusions of similar researches, namely that the two-dimensional method may lead to incorrect results concerning the available SSD. This method is not entirely reliable, given that, on the one hand, the horizontal alignment is considered straight and, on the other hand, only the road axis is considered and therefore cross-sectional elements are not taken into account, although they greatly affect visibility conditions. As far as road safety in relation to the available SSD is concerned, it is concluded that design using marginal values of the alignment parameters, as they are given in road design guidelines, entails the existence of inadequate SSD.The key factors that may reduce or even lead to insufficient available SSD are the following: •The median safety barrier, in cases of motorways, in left-turn horizontal curves overlapped with crest vertical curves, especially in the overtaking (inner) lane. Restriction of the available SSD is caused due to the short lateral distance of the driver from the safety barrier, combined with the form of the alignment. Similarly, SSD shortage may occur in case of a tunnel, where the lateral distance of the driver from the sidewall is about the same as the corresponding distance from the median safety barrier.•The traffic barrier on either side of the road and the cut slopes, mainly in cases of undivided roads with one travelling lane per direction. The problem becomes more pronounced as the lateral distance between the driver and the side obstacle is reduced, therefore more critical are the cases of roads with smaller widths of traffic areas and even more in cases of right-turn horizontal curves overlapped with crest vertical curves.•The width of outer shoulder in cases of cut slopes. It is obvious that the problem intensifies in cases of small width shoulders (mainly on existing roads), vertical walls in areas of technical works etc.The proposed methodology constitutes a comprehensive approach to simulate simultaneously both the cross-section elements and the dynamics of vehicle movement during emergency braking situations, taking into account the elements of the road and its environment that affect visibility levels. The approach of SSD problem is made in the three-dimensional space, in the sense that both the road and its environment are treated as a whole, as opposed to the usual practice of SSD analysis. The main advantages of the proposed methodology include:•The procedure of entering the required parameters and creating the three-dimensional road and roadside model is simple, fast and reliable, giving the designer the possibility to explore the influence of a large number of factors involved in SSD assessment.•All the road elements and features are represented in a realistic way.•The proposed approach for determining the available SSD, through analytical equations, is flexible and efficient.•It is indicated, at each position along the road, the cause that leads to restricted or insufficient SSD, therefore corrective adjustments can be immediately made by the designer.•The three-dimensional extension of the visibility diagram provides the possibility to evaluate, in every position, the road length in front of the driver that is visible and the SSD deficiency, as well as the cause of SSD restriction in positions where SSD is insufficient.•With the use of perspective images created along the road, the quality check of the three-dimensional alignment can be carried out and also SSD assessment can be performed directly, without the use of visibility diagrams.This methodology can be applied to any road environment in which SSD assessment is required, while its accuracy is variable and is selected by the designer, depending on the importance and the design stage of the road under consideration.Στόχος της παρούσας Διδακτορικής Διατριβής είναι η ανάπτυξη μεθόδου διερεύνησης της επάρκειας του Μήκους Ορατότητας για Στάση (ΜΟΣ), με ταυτόχρονη θεώρηση των παραγόντων επιρροής της παρεχόμενης ασφάλειας μιας οδού, δηλαδή των στοιχείων του γεωμετρικού σχεδιασμού της, του οχήματος και του χρήστη – οδηγού, στο πλαίσιο αξιολόγησης της παρεχόμενης ασφάλειας μιας οδού με βάση τον ανθρώπινο παράγοντα. Είναι γεγονός ότι, τόσο κατά την υφιστάμενη πρακτική αξιολόγησης της ορατότητας, όσο και σε αρκετές σχετικές έρευνες, η γεωμετρία της οδού δεν λαμβάνεται πλήρως υπόψη, δεδομένης της απλοποιημένης και αποσπασματικής θεώρησης του οδικού περιβάλλοντος σε δισδιάστατο χώρο. Ως εκ τούτου, οι υφιστάμενες δισδιάστατες μέθοδοι σχεδιασμού, ενδέχεται να υπερεκτιμήσουν ή να υποτιμήσουν τα διαθέσιμα μήκη ορατότητας, οδηγώντας σε αδικαιολόγητη αύξηση του κόστους ή/και του βαθμού επικινδυνότητας της οδού.Επομένως, η ορθότερη αντιμετώπιση του ζητήματος της επάρκειας ορατότητας αποτελεί η μεθόδευσή της μέσω της τρισδιάστατης μελέτης, με χρήση αναλυτικών προτύπων, έτσι ώστε να λαμβάνονται ταυτόχρονα υπόψη όλα τα χαρακτηριστικά της οδού και του περιβάλλοντός της. Επιπλέον, η δημιουργία προοπτικών εικόνων από τη θέση του οδηγού κατά μήκος της οδού αποτελεί χρήσιμο εργαλείο για τον εντοπισμό προβληματικών από άποψη ορατότητας τμημάτων. Σε αυτό το πλαίσιο, έχουν αναπτυχθεί τρισδιάστατες μέθοδοι, οι οποίες επιτρέπουν τον ακριβή προσδιορισμό του πραγματικού πεδίου όρασης του οδηγού. Ωστόσο, σε καμία από αυτές τις προσεγγίσεις δεν περιλαμβάνεται μια ολοκληρωμένη μέθοδος για την προσομοίωση ταυτόχρονα τόσο των στοιχείων της διατομής, όσο και της δυναμικής της κίνησης των οχημάτων κατά τη διάρκεια έκτακτων καταστάσεων πέδησης. Η προτεινόμενη τρισδιάστατη αναλυτική μέθοδος αναπτύχθηκε με στόχο τη δημιουργία ενός ολοκληρωμένου εργαλείου ανάλυσης της ορατότητας. Για τις ανάγκες της παρούσας Διδακτορικής Διατριβής, η υπόψη μέθοδος ενσωματώθηκε και αποτελεί μέρος του λογισμικού οδοποιίας «Η12», το οποίο έχει αναπτυχθεί από τον συγγραφέα της Διδακτορικής Διατριβής, και συνοψίζεται στα εξής στάδια:•Δημιουργία του τρισδιάστατου προσομοιώματος της οδού και του παρόδιου χώρου, με χρήση της μεθόδου του τριγωνισμού.•Προσδιορισμός του απαιτούμενου ΜΟΣ, με βάση βελτιωμένη προσέγγιση της υφιστάμενης πρακτικής, όπου λαμβάνεται υπόψη η επιρροή της πραγματικής κλίσης στη μηκοτομή καθώς και τα δυναμικά χαρακτηριστικά του οχήματος κατά την κίνησή του σε οριζόντια καμπύλη.•Προσδιορισμός του διατιθέμενου ΜΟΣ, μέσω του προσδιορισμού των (πιθανών) σημείων τομής των γραμμών όρασης μεταξύ οφθαλμού οδηγού – εμποδίου, και των τριγώνων που αναπαριστούν την επιφάνεια της οδού και του παρόδιου χώρου, με χρήση αναλυτικών σχέσεων.•Αξιολόγηση επάρκειας ΜΟΣ μέσω επαναληπτικού αλγορίθμου, με βάση τη διαφορά του απαιτούμενου από το διατιθέμενο ΜΟΣ ώστε είναι εφικτός ο προσδιορισμός περιοχών κατά μήκος της οδού όπου οι γραμμές όρασης μεταξύ οφθαλμού οδηγού – εμποδίου διακόπτονται από κάποιο εμπόδιο.•Εξαγωγή των αποτελεσμάτων της ανάλυσης με τη μορφή διαγραμμάτων απεικόνισης μεταξύ του απαιτούμενου και διατιθέμενου ΜΟΣ. Συγκεκριμένα, παράγονται τα διαγράμματα αντιστοίχησης μεταξύ απαιτούμενου και διατιθέμενου ΜΟΣ, καθώς και η τρισδιάστατη επέκταση του διαγράμματος ορατότητας, μέσω της οποίας περιγράφονται, για κάθε σημείο της οδού, οι συνθήκες ορατότητας στο υπολειπόμενο τμήμα της.•Δημιουργία προοπτικών εικόνων από τη θέση του οδηγού, κατά μήκος της υπό αξιολόγηση οδού.Με χρήση του λογισμικού Η12, η προτεινόμενη τρισδιάστατη μέθοδος εφαρμόζεται σε δύο περιπτώσεις – παραδείγματα, με στόχο τη συσχέτιση των αποτελεσμάτων με την αντίστοιχη δισδιάστατη προσέγγιση η οποία βασίζεται στη μηκοτομή της οδού. Επίσης, διερευνάται κατά πόσο η επιρροή βασικών γεωμετρικών παραμέτρων δύναται να επιβάλει δεσμεύσεις στο ΜΟΣ, ώστε αυτές να λαμβάνονται υπόψη κατά τον σχεδιασμό.Από την παραπάνω συσχέτιση, προκύπτει ότι τα αποτελέσματα των δύο αυτών προσεγγίσεων, διαφέρουν σε μεγάλο βαθμό και επιβεβαιώνεται ότι η δισδιάστατη θεώρηση δύναται να οδηγήσει σε εσφαλμένα αποτελέσματα αναφορικά με το διατιθέμενο ΜΟΣ. Επιπλέον, τεκμηριώνεται το γεγονός ότι ο σχεδιασμός οδών με χρήση οριακών τιμών στις παραμέτρους χάραξης, όπως αυτές δίδονται στις οδηγίες σχεδιασμού οδών, έχει ως συνέπεια την ύπαρξη ανεπαρκών μηκών ορατότητας. Καθοριστικούς παράγοντες για τον περιορισμό του ΜΟΣ αποτελούν το κεντρικό (σε διαχωρισμένο οδόστρωμα) και τα πλευρικά στηθαία ασφαλείας, τα τοιχία σηράγγων, τα πρανή της οδού σε όρυγμα, καθώς και το πλάτος του μη σταθεροποιημένου ερείσματος σε όρυγμα. Η προτεινόμενη μέθοδος αποτελεί μια ολοκληρωμένη προσέγγιση στη διερεύνηση της επάρκειας ορατότητας, καθώς κατά τη διαδικασία πέδησης είναι δυνατή η ταυτόχρονη προσομοίωση τόσο των στοιχείων της διατομής, όσο και της δυναμικής της κίνησης των οχημάτων. Επιπλέον, παρέχεται η δυνατότητα παραμετρικής εισαγωγής των στοιχείων της οδού και του περιβάλλοντος οδικού χώρου και, ως εκ τούτου, η αξιολόγηση των επιπέδων ορατότητας σε οποιοδήποτε οδικό περιβάλ
