Modris Dobelis | Riga Technical university (original) (raw)
Papers by Modris Dobelis
Engineering graphics educators have been studying students’ modeling strategies and methods of ev... more Engineering graphics educators have been studying students’ modeling strategies and methods of evaluating models for approximately twenty years. Over the last two years studies have been conducted to gain an understanding of students’ engineering graphics literacy by having students read an assembly drawing, visualize the various parts, and then model the parts within a constraint-based modeling program. These studies revealed that the modeling test used was related to other measures of student success in courses – spatial visualization ability, score on the final project, and score on the final exam. Some of the concerns raised through conducting these studies were that the time required to complete the test and the time required to evaluate the models was too long. Recommendations included using a shorter modeling activity, examining a more efficient way of evaluating the models, and conducting qualitative methods for evaluating student modeling strategies
Residential and public buildings are one of the essential energy consumers. The majority of Europ... more Residential and public buildings are one of the essential energy consumers. The majority of European buildings were constructed within the period from mid-1950ies to the late 1990ies. Currently the retrofitting process is too slow. The main barriers are complicated retrofitting process, variety of available technologies as well as precision of estimated energy savings calculations. This paper is prepared in scope of work done within the European Regional Development Fund project “Nearly Zero Energy Solutions for Unclassified Buildings”. The main aim of this study is to develop full modular retrofitting process based on 3D laser scanning minimizing time consumed for architectural project development, on-site construction works as well as to ensure correct energy simulation. Paper presents results of Latvian case building 3D scanning results, architectural project development specifics as well as selection of optimal thermal insulation layout and energy simulations. Study analyses mai...
During the Fall 2011 semester, an engineering graphics literacy assessment was administered to st... more During the Fall 2011 semester, an engineering graphics literacy assessment was administered to students at Riga Technical University and North Carolina State University who were enrolled in constraint-based/parametric modeling courses. The students were asked to model seven parts in an assembly drawing of a device within a 110 minute class period. The parts ranged in complexity from a ball to a valve body. Students also completed the Purdue Spatial Visualization Test – Visualization of Rotations (PSVT:R) to determine if the engineering graphics literacy assessment scores were related to spatial visualization ability. The researchers did not find significant differences between the universities on scores on the modeling test or scores on the PSVT:R. Overall, there was a significant correlation between scores on the modeling test and scores on the PSVT:R
Une personne marchant dans un champ trace un chemin. La perception de cette modification du champ... more Une personne marchant dans un champ trace un chemin. La perception de cette modification du champ influence sa marche ainsi que les prochaines marches qu'il y fera. Nous nous inspirons de cette métaphore comme principe d'exploration d'une base de données complexes pour répondreà un questionnement et favoriser sa compréhension. Nous parlons d'interfacé enactive, permettantà l'utilisateur de construire de façon incrémentale sa connaissance d'un domaine. Ce principe sera illustréà partir d'une base de données patrimoniale qui sera le support du questionnement de l'utilisateur. Trois modèles sont utilisés : un modèle ontologique issue des connaissances sur le domaine exploré; un modèle statistique de co-occurence des mots extraits de la base de données; et un modèle des préférences de l'utilisateur. L'utilisation conjointe de ces trois modèles assure la co-navigation dans la base de données. Une des originalités de ce travail réside dans l'incarnation des données : elles sont représentées par des objets 3d (en trois dimensions) dotés d'un comportement autonome. Cette approche permetà un utilisateur de définir son parcours pendant sa navigation, de visualiser des données qui sont considérées pertinentes pour lui,à partir de ses interactions. Plus l'utilisateurévolue dans son parcours, plus il le structure et plus celui-ci correspondà son questionnement.
The quality of modern engineering education is directly linked with the students’ ability to crea... more The quality of modern engineering education is directly linked with the students’ ability to create and read the drawings of engineering structures. The subject “Descriptive Geometry and Engineering Graphics” taught in the undergraduate engineering studies develops students’ ability to analyse both the shape and design of real objects and, along with the spatial reasoning, the technical thinking. The development of spatial skills for engineering students is closely related with the success in their future professional career. The new information technologies (IT) offer novel opportunities to enhance the classic teaching approach used so far during mastering quite complicate and extensive courses, like engineering graphics. Augmented Reality (AR) is one of the many challenges of modern IT technologies which recently became available also for education purposes. It is supposed that AR will provide new possibilities to teach the contemporary generation of students in an attractive and ...
Universities have eliminated many courses in engineering graphics and descriptive geometry over t... more Universities have eliminated many courses in engineering graphics and descriptive geometry over the last 30 years and typically replaced them with a single course that is focused on solid modeling and engineering design. CAD instruction appears to be the main focus of engineering graphics courses that remain, but faculty have many opinions about what is essential when preparing students for careers. Spatial abilities have been used as a predictor of success in several engineering and technology disciplines. In engineering graphics courses, scores on spatial tests have also been used to predict success. Other studies have shown that an intervention can improve spatial abilities in students who score low on tests in this area. For this study, the primary research question was, how well do current engineering and technology students read engineering drawings, and is there a relationship between reading engineering drawings and spatial visualization? Can students take the information gi...
54 Generally, a fractal most often referred to as “a rough shape that can be subdivided in parts,... more 54 Generally, a fractal most often referred to as “a rough shape that can be subdivided in parts, each of which is (at least approximately) a reduced-size copy of the whole.” The father of fractal geometry Benoît Mandelbrot formulated this term in 1975. A fractal has a complicated shape. Certain features characterize a graphical representation of the fractal by mathematical equation: it is self-similar, has fi ne structure, and is very diffi cult to describe it using Euclidian geometric language. It might seem like a nice mathematic abstraction, but fractal geometry, as we believe – is the foundation of everything that exists.
Mācību līdzeklis ir paredzēts mācību priekšmeta "Tēlotāja ģeometrija" apguvei RTU studi... more Mācību līdzeklis ir paredzēts mācību priekšmeta "Tēlotāja ģeometrija" apguvei RTU studiju programmu ietvaros un tas satur teorētisku materiālu un praktiskus piemērus telpisku objektu attēlošanai divās dimensijā un pozicionālu un metrisku uzdevumu risināšanai ar tiem. Otrā daļā aplūkoti perspektīvas, ēnu teorijas un kotēto projekciju teorētiskie un praktiskie jautājumi. Pamatā grāmata paredzēta Arhitektūras fakultātes studentiem
Present time features rapid advancements in information technologies, which are used to communica... more Present time features rapid advancements in information technologies, which are used to communicate architectural design projects. Most of users are primarily interested in models of buildings, terrain, vegetation, and traffic networks. A European Organization for Experimental Photogrammetric Research survey on city models showed that 95 % of participants were most interested in 3D building data. Computer technology, computer graphics, and computer-aided design (CAD) now offer powerful tools for creating and visualizing digital models of cities. Manual measurement and entry are impractical; so researchers use various sensors to acquire accurate data for 3D urban landscapes. They then integrate the resulting 3D building models into spatial databases and geographic information systems (GIS) to support urban planning and analysis applications. The complexity of application demands and technology challenges make urban modelling an intensive research area.
During the Spring 2011 semester, an engineering graphics literacy assessment was developed by a v... more During the Spring 2011 semester, an engineering graphics literacy assessment was developed by a visiting Fulbright Scholar. The assessment was administered in a junior-level constraint-based modeling course. Twenty-nine students were asked to model seven parts given in an assembly drawing of a device within a 110 minute class period. The parts in the assembly ranged in complexity from a ball to a valve body. Students were given a ruler to measure parts on the B-size drawing and determine sizes of features based on the given scale (2:1). There was a positive relationship between the scores on the activity and the pace at which each student completed the parts. Only eight students modeled all seven parts in the assembly. There were significant correlations between the scores on the modeling assessment and other measures in the course (final project, final exam, and final course average). This paper summarizes how students performed on the assessment (number of parts correctly modeled,...
The present study was undertaken to identify proteins interacting with PrP C that could provide n... more The present study was undertaken to identify proteins interacting with PrP C that could provide new insights into its physiological functions and pathological role. We performed a target search for lysosomal network protein, Rab7a and Rab9, in frontal cortex and cerebellum of human brain from patients with sCJD-MM1 and sCJD-VV2. The intracellular level of Rab7a was increased significantly, when compared with healthy age-matched control. Interactions of PrP C and Rab7a/Rab9 were further investigated by using confocal laser scanning microscopy. Immunofluorescence results suggested potential interactions of Rab7a and PrP C. siRNA against the Rab7a gene was used to knockdown the expression of Rab7a protein in primary cell culture of cortical neurons from wild type mice. This depleted Rab7a resulted an impairment of PrP C trafficking leading to an accumulation of PrP C in the endocytosis pathway. Furthermore, interactions of Tau and Rab7a were investigated by using western blot analysis and confocal laser scanning microscopy. Cell cultures of cortex of wildtype mice were treated with siRNA-Tau, siRNA-Rab7 and control siRNA followed by immunofluorescence. The results of immunofluorescence suggested potential interaction of Tau and Rab7a. Cells lines treated with siRNA-Tau, the intracellular levels of Rab7a and Rab9 significantly increases and their localization is also modified. When we transfected this cells lines with siRNA-rab7a the accumulation of Tau decreases in cytosolic region and their localization was also modified when compared with control cells. In conclusion, this study may help to understand and characterize the subtype specific disease progression in CJD cases. Furthermore, it could be a step ahead to development of new treatment strategies for diseases subtype specific manner.
2012 ASEE Annual Conference & Exposition Proceedings
Geometry and Graphics. Branoff's research interests include spatial visualization in undergraduat... more Geometry and Graphics. Branoff's research interests include spatial visualization in undergraduate students and the effects of online instruction for preparing technology education teachers and engineers. Along with teaching courses in introductory engineering graphics, computer-aided design, descriptive geometry, and instructional design, he has conducted CAD and geometric dimensioning and tolerancing workshops for both high school teachers and local industry.
Engineering graphics educators have been studying students’ modeling strategies and methods of ev... more Engineering graphics educators have been studying students’ modeling strategies and methods of evaluating models for approximately twenty years. Over the last two years studies have been conducted to gain an understanding of students’ engineering graphics literacy by having students read an assembly drawing, visualize the various parts, and then model the parts within a constraint-based modeling program. These studies revealed that the modeling test used was related to other measures of student success in courses – spatial visualization ability, score on the final project, and score on the final exam. Some of the concerns raised through conducting these studies were that the time required to complete the test and the time required to evaluate the models was too long. Recommendations included using a shorter modeling activity, examining a more efficient way of evaluating the models, and conducting qualitative methods for evaluating student modeling strategies
Residential and public buildings are one of the essential energy consumers. The majority of Europ... more Residential and public buildings are one of the essential energy consumers. The majority of European buildings were constructed within the period from mid-1950ies to the late 1990ies. Currently the retrofitting process is too slow. The main barriers are complicated retrofitting process, variety of available technologies as well as precision of estimated energy savings calculations. This paper is prepared in scope of work done within the European Regional Development Fund project “Nearly Zero Energy Solutions for Unclassified Buildings”. The main aim of this study is to develop full modular retrofitting process based on 3D laser scanning minimizing time consumed for architectural project development, on-site construction works as well as to ensure correct energy simulation. Paper presents results of Latvian case building 3D scanning results, architectural project development specifics as well as selection of optimal thermal insulation layout and energy simulations. Study analyses mai...
During the Fall 2011 semester, an engineering graphics literacy assessment was administered to st... more During the Fall 2011 semester, an engineering graphics literacy assessment was administered to students at Riga Technical University and North Carolina State University who were enrolled in constraint-based/parametric modeling courses. The students were asked to model seven parts in an assembly drawing of a device within a 110 minute class period. The parts ranged in complexity from a ball to a valve body. Students also completed the Purdue Spatial Visualization Test – Visualization of Rotations (PSVT:R) to determine if the engineering graphics literacy assessment scores were related to spatial visualization ability. The researchers did not find significant differences between the universities on scores on the modeling test or scores on the PSVT:R. Overall, there was a significant correlation between scores on the modeling test and scores on the PSVT:R
Une personne marchant dans un champ trace un chemin. La perception de cette modification du champ... more Une personne marchant dans un champ trace un chemin. La perception de cette modification du champ influence sa marche ainsi que les prochaines marches qu'il y fera. Nous nous inspirons de cette métaphore comme principe d'exploration d'une base de données complexes pour répondreà un questionnement et favoriser sa compréhension. Nous parlons d'interfacé enactive, permettantà l'utilisateur de construire de façon incrémentale sa connaissance d'un domaine. Ce principe sera illustréà partir d'une base de données patrimoniale qui sera le support du questionnement de l'utilisateur. Trois modèles sont utilisés : un modèle ontologique issue des connaissances sur le domaine exploré; un modèle statistique de co-occurence des mots extraits de la base de données; et un modèle des préférences de l'utilisateur. L'utilisation conjointe de ces trois modèles assure la co-navigation dans la base de données. Une des originalités de ce travail réside dans l'incarnation des données : elles sont représentées par des objets 3d (en trois dimensions) dotés d'un comportement autonome. Cette approche permetà un utilisateur de définir son parcours pendant sa navigation, de visualiser des données qui sont considérées pertinentes pour lui,à partir de ses interactions. Plus l'utilisateurévolue dans son parcours, plus il le structure et plus celui-ci correspondà son questionnement.
The quality of modern engineering education is directly linked with the students’ ability to crea... more The quality of modern engineering education is directly linked with the students’ ability to create and read the drawings of engineering structures. The subject “Descriptive Geometry and Engineering Graphics” taught in the undergraduate engineering studies develops students’ ability to analyse both the shape and design of real objects and, along with the spatial reasoning, the technical thinking. The development of spatial skills for engineering students is closely related with the success in their future professional career. The new information technologies (IT) offer novel opportunities to enhance the classic teaching approach used so far during mastering quite complicate and extensive courses, like engineering graphics. Augmented Reality (AR) is one of the many challenges of modern IT technologies which recently became available also for education purposes. It is supposed that AR will provide new possibilities to teach the contemporary generation of students in an attractive and ...
Universities have eliminated many courses in engineering graphics and descriptive geometry over t... more Universities have eliminated many courses in engineering graphics and descriptive geometry over the last 30 years and typically replaced them with a single course that is focused on solid modeling and engineering design. CAD instruction appears to be the main focus of engineering graphics courses that remain, but faculty have many opinions about what is essential when preparing students for careers. Spatial abilities have been used as a predictor of success in several engineering and technology disciplines. In engineering graphics courses, scores on spatial tests have also been used to predict success. Other studies have shown that an intervention can improve spatial abilities in students who score low on tests in this area. For this study, the primary research question was, how well do current engineering and technology students read engineering drawings, and is there a relationship between reading engineering drawings and spatial visualization? Can students take the information gi...
54 Generally, a fractal most often referred to as “a rough shape that can be subdivided in parts,... more 54 Generally, a fractal most often referred to as “a rough shape that can be subdivided in parts, each of which is (at least approximately) a reduced-size copy of the whole.” The father of fractal geometry Benoît Mandelbrot formulated this term in 1975. A fractal has a complicated shape. Certain features characterize a graphical representation of the fractal by mathematical equation: it is self-similar, has fi ne structure, and is very diffi cult to describe it using Euclidian geometric language. It might seem like a nice mathematic abstraction, but fractal geometry, as we believe – is the foundation of everything that exists.
Mācību līdzeklis ir paredzēts mācību priekšmeta "Tēlotāja ģeometrija" apguvei RTU studi... more Mācību līdzeklis ir paredzēts mācību priekšmeta "Tēlotāja ģeometrija" apguvei RTU studiju programmu ietvaros un tas satur teorētisku materiālu un praktiskus piemērus telpisku objektu attēlošanai divās dimensijā un pozicionālu un metrisku uzdevumu risināšanai ar tiem. Otrā daļā aplūkoti perspektīvas, ēnu teorijas un kotēto projekciju teorētiskie un praktiskie jautājumi. Pamatā grāmata paredzēta Arhitektūras fakultātes studentiem
Present time features rapid advancements in information technologies, which are used to communica... more Present time features rapid advancements in information technologies, which are used to communicate architectural design projects. Most of users are primarily interested in models of buildings, terrain, vegetation, and traffic networks. A European Organization for Experimental Photogrammetric Research survey on city models showed that 95 % of participants were most interested in 3D building data. Computer technology, computer graphics, and computer-aided design (CAD) now offer powerful tools for creating and visualizing digital models of cities. Manual measurement and entry are impractical; so researchers use various sensors to acquire accurate data for 3D urban landscapes. They then integrate the resulting 3D building models into spatial databases and geographic information systems (GIS) to support urban planning and analysis applications. The complexity of application demands and technology challenges make urban modelling an intensive research area.
During the Spring 2011 semester, an engineering graphics literacy assessment was developed by a v... more During the Spring 2011 semester, an engineering graphics literacy assessment was developed by a visiting Fulbright Scholar. The assessment was administered in a junior-level constraint-based modeling course. Twenty-nine students were asked to model seven parts given in an assembly drawing of a device within a 110 minute class period. The parts in the assembly ranged in complexity from a ball to a valve body. Students were given a ruler to measure parts on the B-size drawing and determine sizes of features based on the given scale (2:1). There was a positive relationship between the scores on the activity and the pace at which each student completed the parts. Only eight students modeled all seven parts in the assembly. There were significant correlations between the scores on the modeling assessment and other measures in the course (final project, final exam, and final course average). This paper summarizes how students performed on the assessment (number of parts correctly modeled,...
The present study was undertaken to identify proteins interacting with PrP C that could provide n... more The present study was undertaken to identify proteins interacting with PrP C that could provide new insights into its physiological functions and pathological role. We performed a target search for lysosomal network protein, Rab7a and Rab9, in frontal cortex and cerebellum of human brain from patients with sCJD-MM1 and sCJD-VV2. The intracellular level of Rab7a was increased significantly, when compared with healthy age-matched control. Interactions of PrP C and Rab7a/Rab9 were further investigated by using confocal laser scanning microscopy. Immunofluorescence results suggested potential interactions of Rab7a and PrP C. siRNA against the Rab7a gene was used to knockdown the expression of Rab7a protein in primary cell culture of cortical neurons from wild type mice. This depleted Rab7a resulted an impairment of PrP C trafficking leading to an accumulation of PrP C in the endocytosis pathway. Furthermore, interactions of Tau and Rab7a were investigated by using western blot analysis and confocal laser scanning microscopy. Cell cultures of cortex of wildtype mice were treated with siRNA-Tau, siRNA-Rab7 and control siRNA followed by immunofluorescence. The results of immunofluorescence suggested potential interaction of Tau and Rab7a. Cells lines treated with siRNA-Tau, the intracellular levels of Rab7a and Rab9 significantly increases and their localization is also modified. When we transfected this cells lines with siRNA-rab7a the accumulation of Tau decreases in cytosolic region and their localization was also modified when compared with control cells. In conclusion, this study may help to understand and characterize the subtype specific disease progression in CJD cases. Furthermore, it could be a step ahead to development of new treatment strategies for diseases subtype specific manner.
2012 ASEE Annual Conference & Exposition Proceedings
Geometry and Graphics. Branoff's research interests include spatial visualization in undergraduat... more Geometry and Graphics. Branoff's research interests include spatial visualization in undergraduate students and the effects of online instruction for preparing technology education teachers and engineers. Along with teaching courses in introductory engineering graphics, computer-aided design, descriptive geometry, and instructional design, he has conducted CAD and geometric dimensioning and tolerancing workshops for both high school teachers and local industry.
PhD Thesis
The dissertation is dedicated to the research of mechanical properties, biochemical composition a... more The dissertation is dedicated to the research of mechanical properties, biochemical composition and structure of both the mineral and organic components of compact bone tissue, as well as the development of the model which describes the mechanical behaviour of the bone tissue as a composite material using the experimental results obtained in the present study .