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This paper presents the evolution of and influence that the use of a triangular grid has had on the transformation of layered grid structures during the last two centuries. Historical facts, technological advances, economic and social crises among other factors influence the process of change and evolution of the grid systems in architecture to make construction processes more efficient by reducing the consumption of materials and qualified labor. Geometry and structure innovate styles and processes that are perfected over the years, achieving lighter and more stable structures. For the purpose of this paper historical data will be collected that allows the development of a theory that shows the influence of various periods based on technological advances. This research shows four historical periods in the evolution of layered grid structures. Being the triangular grid a widely used methodology in the construction of a diversity of geometric proposals and innovative construction systems for the solution of a diversity of buildings from the first domes built in the early 19th century to the free-form structures built from the late 20th century to the present day.

The use of self-organizing maps and artificial neural networks for structural health monitoring is presented in this paper. The authors recently developed a nonparametric structural damage detection algorithm for extracting damage indices from the ambient vibration response of a structure. The algorithm is based on self-organizing maps with a multilayer feedforward pattern recognition neural network. After the training of the self-organizing maps, the algorithm was tested analytically under various damage scenarios based on stiffness reduction of beam members and boundary condition changes of a grid structure. The results indicated that proposed algorithm can successfully locate and quantify damage on the structure. Scopus

Prema zadanim podacima drvene rešetkaste krovne konstrukcije potrebno je dimenzionirati glavni nosač i sekundarni nosač konstrukcije te vjetrovne spregove te nacrtati radioničke nacrte glavnog nosača te detalje dodatnih spojeva. Based on given data of truss structure it is needed to design the main structure, secondary structure, wind bracings and to make drawings of the main structure and details of joints.

The arrangement and form of the image sensor have a fundamental effect on any further image processing operation and image visualization. In this paper, we present a software-based method to change the arrangement and form of pixel sensors that generate hexagonal pixel forms on a hexagonal grid. We evaluate four different image sensor forms and structures, including the proposed method. A set of 23 pairs of images; randomly chosen, from a database of 280 pairs of images are used in the evaluation. Each pair of images have the same semantic meaning and general appearance, the major difference between them being the sharp transitions in their contours. The curviness variation is estimated by effect of the first and second order gradient operations, Hessian matrix and critical points detection on the generated images; having different grid structures, different pixel forms and virtual increased of fill factor as three major properties of sensor characteristics. The results show that the grid structure and pixel form are the first and second most important properties. Several dissimilarity parameters are presented for curviness quantification in which using extremum point showed to achieve distinctive results. The results also show that the hexagonal image is the best image type for distinguishing the contours in the images. © 2018 by the authors. Licensee MDPI, Basel, Switzerland. open access

Prema zadanim podacima drvene rešetkaste krovne konstrukcije potrebno je dimenzionirati glavni nosač i sekundarni nosač konstrukcije te vjetrovne spregove te nacrtati radioničke nacrte glavnog nosača te detalje dodatnih spojeva., Based on given data of truss structure it is needed to design the main structure, secondary structure, wind bracings and to make drawings of the main structure and details of joints.

Spatial structures have shown a great development, mainly since the post-war years from the middle of the twentieth century. They have become a constructive solution which provides lightness and stiffness, while achieving longer spans and reducing energy and used material. In Mexico City, the Sports Palace was completed in 1968 to become a landmark of Mexican architecture and an example of a low-cost, lightweight, dome. This essay shows the geometric influences and foundation behind its design, as well as the development and typological transformation of its structural elements and materials in the finally adopted constructive solution ─the crossed arch. Such solution transformed material and its geometry into a structural typological solution of its own. Here, Félix Candela used constructive and structural elements, previously experienced in other typologies, into solutions to form new types. This way, Candela developed the hyperbolic paraboloid, employing new materials and applying geometry for the structural typological development of the shape of the Sports Palace, achieving a dome which would become a typological model of international architecture. Las estructuras espaciales han mostrado una gran evolución, principalmente desde los años de la posguerra a mitad del siglo XX. Estas estructuras se han convertido en una solución constructiva que otorga ligereza y rigidez, logrando obtener mayores luces y reduciendo el consumo de energía y de materiales. En la Ciudad de México se concluyó el Palacio de los Deportes en el año de 1968 para convertirse en un hito de la arquitectura mexicana y un ejemplo de cubierta aligerada de bajo costo. En este documento se mostrará las influencias y bases geométricas para su diseño, así como su evolución y transformación tipológica de sus elementos estructurales y materiales adoptando al final la solución constructiva de arcos cruzados. Esta solución por si misma transformo el material y su geometría en una solución tipológica. Aquí, Félix Candela utiliza elementos constructivos y estructurales, previamente experimentados en otras tipologías, en soluciones para formar nuevos tipos. De esta manera, Candela desarrolló el paraboloide hiperbólico, el empleo de nuevos materiales y la aplicación de la geometría para el desarrollo tipológico estructural de la forma del Palacio de los Deportes, logrando una cúpula que se convertiría en un modelo tipológico de la arquitectura internacional.

Spatial structures have shown a great development, mainly since the post-war years from the middle of the twentieth century. They have become a constructive solution which provides lightness and stiffness, while achieving longer spans and reducing energy and used material. In Mexico City, the Sports Palace was completed in 1968 to become a landmark of Mexican architecture and an example of a low-cost, lightweight, dome. This essay shows the geometric influences and foundation behind its design, as well as the development and typological transformation of its structural elements and materials in the finally adopted constructive solution ─the crossed arch. Such solution transformed material and its geometry into a structural typological solution of its own. Here, Félix Candela used constructive and structural elements, previously experienced in other typologies, into solutions to form new types. This way, Candela developed the hyperbolic paraboloid, employing new materials and applying geometry for the structural typological development of the shape of the Sports Palace, achieving a dome which would become a typological model of international architecture.

Voziščne konstrukcije so najpomembnejši element vsake prometnice in tisti del, od katerega je najbolj odvisna varnost, in nivo uporabe prometnice. Prav tako je element, ki pomeni bistven investicijski element pri vsaki gradnji prometnice in element, v katerega se največkrat posega, vzdržuje, obnavlja … Čeprav se zdi, da gre za enostavno konstrukcijo, tako po izboru materialov, tehnologiji gradnje kot matematičnemu modelu za analizo konstrukcije, pa v praksi vse do danes nismo uspeli učinkovito rešiti probleme trajnih deformacij voziščnih konstrukcij. Kljub razvoju materialov v zadnjem obdobju, vsaj kar se tiče vezanih nosilnih plasti, pa problemi voziščnih konstrukcij ostajajo enaki, malo je inovativnih rešitev in modelov. Nevezane nosilne plasti imajo izrazito slabost, da niso sposobne prevzeti nateznih napetosti v horizontalni ravnini. Zaradi tega prihaja do plastičnih deformacij, ki se posledično prenašajo na površino vozišča v obliki razpok in kolesnic. Kljub preoblikovanju naravnega kamnitega materiala in dodajanjem veziv, se še posebej pri preobremenitvah ali poslabšanih hidrogeoloških pogojih naravnih temeljnih tal, ne moremo izogniti vertikalnim deformacijam vozišča, ki so posledica prekomernih horizontalnih napetosti v nevezanih plasteh voziščne konstrukcije. Reševanje z uporabo ojačitvenih mrež (geomrež) v horizontalnem nivoju nevezanih nosilnih plasti, ne da želenih rezultatov, saj prihaja do strižnih deformacij med nivoji ojačitev. V zadnjih letih pa vse do danes, je ideja doživela velik razvoj v smeri 3D struktur vertikalno nameščenih trakov - geocelic. Vezane deformabilne obrabno-nosilne plasti v kombinaciji z geocelicami ojačenimi nevezanimi nosilnimi plastmi zemljin predstavljajo učinkovit inovativen sistem voziščne konstrukcije, ki s svojo sestavo zagotavlja trajno elastičnost, fleksibilnost in zadostno nosilnost same konstrukcije. Eksperimentalna analiza je pokazala bistveno izboljšanje nosilnosti in zmanjšanje deformacij z uporabe mrežne strukture vertikalnih trakov geocelic. Uporabljen material za takšno strukturo, pa je lahko v celoti uporabljen iz recikliranih sintetičnih materialov, kar je z uporabo lokalnih gradbenih materialov lahko tudi pomemben prispevek ekološki gradnji, manjši porabi energije in zmanjšanju emisij v okolje. Pavement structure is the most important element of every traffic infrastructure, it is the element on which safety and the level of usage depends most. Pavement structure is also the most crucial element investment wise, since it needs most interventions, maintenance work and repairs. Eventhough it seems like pavement structure is material wise, construction technology wise and mathematical analytic formula wise a very simple structure, in practice we still haven't successfully solved the problems of pernament deformations of the pavement structures. Despite the progress in materials in the last period, at least regarding bound up bearing layers, pavement structure problems remain the same, there are very few innovative solutions. Unbound bearing layers have a distinct weakness that they are not capable of bearing tensile tension in horizontal plain. This results in plastic deformations that transmit on surface of the pavement as cracks and ruts as a consequence. Despite the transformation of natural grevel and sand materials and adding binders, we can't avoid vertical deformations of the pavement that are the consequence of an excessive horizontal tensions in detached layers of the pavement construction, especially when overloading, or in case of deteriorated hydro-geologic conditions of the natural ground. Solving the problem using geogrids on horizontal level of the detached supporting layers did not give the results we hoped for because shear skids were occurring between the levels of reinforcement. From the very beginning of the idea, till today, the idea experienced a great development in the direction of 3D structures vertically placed strips - geocells. Binded deformed defensively-supporting layers in combination with geocell reinforced unbound bearing layers of earth represent effective and innovative system of pavement structure with it's structure that guarantee permanent elasticity, flexibility and adequate bearing strength of the construction itself. Experimental analysis showed a crucial improvement of the bearing strength and reduction of deformation when using geogrids. The material, used for that kind of structure can be fully made out of recycled synthetic materials, which can be, with usage of local construction materials, an important contribution to ecological building, reduced consumption of energy and reduction of environmental emissions.

The minimum mass designs of state of the art helical circumferential grids are compared to axial helical grids. Analytical models based on the classical laminate theory deliver optimization results in less than one second. Using finite element models the obtained results are validated and adjusted in a second optimization step. Studies on the influence of rib heights and Young’s modulus show potential to create lighter grids in axial helical design than in helical circumferential design. This is shown for medium length cylinders from relatively low up to very high load levels.

A coterie is a set of subsets (called quorums) of the processes in a distributed system such that any two quorums intersect with each other and is mainly used to solve the mutual exclusion problem in a quorum-based algorithm. The choice of a coterie sensitively affects the performance of the algorithm and it is known that nondominated (ND) coteries achieve good performance in terms of criteria such as availability and load. On the other hand, grid coteries have some other attractive features : 1) A quorum size is small, which implies a low message complexity, and 2) a quorum is constructible on the fly, which benefits a low space complexity. However, they are not ND coteries unfortunately. To construct ND coteries having the favorite features of grid coteries, we introduce the transversal merge operation that transforms a dominated coterie into an ND coterie and apply it to grid coteries. We call the constructed ND coteries ND grid coteries. These ND grid coteries have availability higher than the original ones, inheriting the above desirable features from them. To demonstrate this fact, we then investigate their quorum size, load, and availability, and propose a dynamic quorum construction algorithm for an ND grid coterie.

Dirençsel ızgara yapılarının uzamsal impuls yanıtlarının üstel olarak azalan biçimden oldukları ve Gauss filtresininkine benzer bir uzamsal frekans yanıtı verdikleri, dolaysıyla da alçak geçiren filtre olarak kullanıldıkları iyi bilinen bir gerçektir. Bu bildiride, ızgara yapısının özyinelemeli bir denklem ile modellenebilmesine karşın bu denklemin özyinelemeli çözümünün olmadığı, fakat çıkış görüntüsünün dirençsel ızgaranın düğüm denklemlerinin çözümü ile elde edilebileceği gösterilmiştir. Bununla birlikte görüntünün boyutlarının aşırı büyüklükte olması durumunda matris tersi temelli bir algoritmanın kullanılmasının olurlu olmadığı açıktır. Bu bildiride dirençsel ızgara düğüm denklemlerinin Jacobi yineleme yöntemi ile çözülebileceği ve bu yöntemin FPGA üzerinde gerçeklemeye uygun olduğu gösterilmiştir. It is well known that resistive grid structures yield exponentially decreasing spatial impulse response yielding a spatial frequency response similar to that of a Gaussian filter, hence used as smoothing filters. In this paper it is shown that although the grid structure can be modeled with a recurrence (difference) equation this equation is not recursively computable but the output image can be obtained by solving the node equations of the resistive grid. However, where the image size is extremely large, it is evident that the use of any matrix inversion based algorithm is not feasible. In this paper it is shown that the solution of node equations of the resistive grid can be carried out using Jacobi iteration method which is also shown to be suitable for implementation on FPGA. Publisher's Version

Date of Conference: 11-13 June 2007 Conference name: IEEE 15th Signal Processing and Communications Applications, 2007 Dikdörtgensel olmayan dalgacık dönüşümüne dayalı çok çözünürlüklü üç boyutlu model sıkıştırılması için iki yöntem önerilmektedir. Bunlar Sıradüzensel Ağaç Yapılarının Kümelere Bölütlenmesi (Set Partitioning In Hierarchical Trees - SPIHT) ve JPEG2000 tekniklerine dayanmaktadır. Üç boyutlu modeller düzenli ızgara yapılar üzerinde tanımlı iki boyutlu imgelere dönüştürülmekte, ve bu gösterim bağlanırlıkla yönlendirilmiş uyarlamalı dalgacık dönüşümünden geçirilerek ortaya çıkan dalgacık kümesi verisi SPITH veya JPEG2000 yöntemlerinden biri uygulanarak bit dizgisine dönüştürülmektedir. SPIHT ile elde edilen bit dizgisinin değişik uzunluklardaki bölümlerinden modelin değişik çözünürlüklerde geri çatmak mümkün olduğundan önerilen bu yöntem modellerin aşamalı gösterimine olanak sağlamaktadır. Dalgacık dönüşümü verilerinin SPIHT ile kodlanmasıyla elde edilen sonuç JPEG2000 ve MPEG-3DGC ile yapılan kodlamanın sonucundan daha başarılı olmuştur. Two compression frameworks that are based on a Set Partitioning In Hierarchical Trees (SPIHT) and JPEG2000 methods are proposed. The 3D mesh is first transformed to 2D images on a regular grid structure. Then, this image-like representation is wavelet transformed employing an adaptive predictor that takes advantage of the connectivity information of mesh vertices. Then SPIHT or JPEG2000 is applied on the wavelet domain data. The SPIHT based method is progressive because the resolution of the reconstructed mesh can be changed by varying the length of the one-dimensional data stream created by SPIHT algorithm. The results of the SPIHT based algorith is observed to be superior to JPEG200 based mesh coder and MPEG-3DGC in rate-distortion.

Grid structures configurations prove to be inherently strong and resilient arrangements for composite materials, without material mismatches (different layer orientations) associated with laminated structures. The absence of material mismatch implies that the grid structures possess inherent resistance to impact damage, delamination and crack propagation. The introduction of grid structures into industry has been hampered by a lack of understanding of their behavior, especially in failure mechanics. In order to improve the knowledge about mechanical behavior including failure of such structures, Finite Element model, of a repetitive volume element (RVE) of grid structure has been defined. Geometrically non-linear structural analyses have been carried out by adopting the research oriented FEM code B2000 in order to simulate the mechanical behavior of the structure. Furthermore, within the B2000 FEM code, a damage progression approach has been implemented in order to simulate the damage on-set and propagation in the selected RVE.

Based on a Space Joint Patent Application several space joints types were developed and implemented in various grid structures. Application of bigger cube space jointtype was realized in different fields. In this paper newest grid structures applications are described: Large TV Suspension Bridge ; Large Tie Node Grid Structure and Tie node Grid Structures Support Structure.

The main objective of this article is to present theoretical and practical results and possibilities of different space joint types implementation in superstructures outfit and equipment. After introducing of new space joint types in light conventional grid structures, the authors are suggesting their implementation in various shipbuilding areas, and in particular within superstructure outfit and equipment. Space joint is a new constructional element for synchronous fastening of crossover rods in and/or on space joint body. At the same time the space joint represents a fastening node within grid structure. New grid structures solutions are based on Patent Cooperation Treaty (PCT), Patent Application No. PCT/GB97/00944, with International Publication Number W 97 / 38229 and some additional research results in this field. Some of present research activities supported by the Ministry of Science and Technology of the Republic of Croatia (Scientific project name: Marine structures and equipment in coastal zone and subsea) have also been presented. The main new grid structures building concept is characterised with structure lightness, simple assembly and adjusting procedures, "maintenance free" structures, ecology friendly structures, accommodation system modules with simplified on board erection possibilities, and multiple usage configurations. Analysing various present construction solutions in ship superstructures, masts, communication facilities, furniture, gangways, telescopic roofs, etc. the authors pointed out concrete proposals for new solutions regarding implementation of mentioned space joint types. Advantages with argumentation for particular topics were described and presented. Developed computer model for one space joint type was described. Computer modelling was performed on basis of finite element method. Special attentions were pointed out regarding contact pressures, deformations, as well as stresses. Up to date testing was mainly realised concerning small-reinforced polyamide type of space joint body and fastening bodies. Preparations for testing procedures of different types from various materials and dimensions have been discussed, too. Special consideration was given to compare theoretical and experimental results concerning forces, deformations, strengths, and contact problems, based on some scientific research results achieved at Faculty of Engineering University of Rijeka. In addition, different aspects of ecology, maintenance, mounting and dismounting procedures, safety, replacement, etc. have been discussed. On basis of mentioned theoretical, experimental and some exploitation results authors proposed usage of different space joint types for implementation in shipbuilding. Authors are also suggesting further research regarding implementation of new predicted space joint types to different fields in shipbuilding and marine structures.