scholarly journals The Effect of Connecting Bridges on Vortex-induced Vibration of Skyscrapers

2021 ◽  
Keyword(s):  
Urban Development ◽  
Vortex Shedding ◽  
Network Size ◽  
Large Network ◽  
Structural Behaviour ◽  
High Rise ◽  
Proposed Model ◽  
Engineering Models ◽  
Structural Connections ◽  
Structural Networks

The shapes of slender skyscrapers are unfavourable for carrying horizontal loads. In this paper, we investigate the possibility of improving their structural behaviour by adding urban-scale networks of structural connections among the buildings. We focus on vibrations of skyscrapers in response to wind-induced vortex shedding. We develop a conceptual model of those structural networks composed of springs, dampers and point masses. The proposed model enables rapid numerical simulations involving large networks, which is not possible in the case of more detailed engineering models. The effect of connections, dilatation gaps, and network size are investigated for random collections of high-rise buildings, and triangular networks of horizontal bar connections among them. It is found that connections efficiently reduce vibrations in the network, especially for large network size. This study aims to be a first step towards uncovering the benefits of a novel form of urban development. A karcsú felhőkarcolók alakja kedvezőtlen a rájuk ható vízszintes terhek viselése szempontjából. Munkánkban a szerkezeti viselkedés javítási lehetőségeit vizsgáljuk az épületeket összekötő szerkezeti kapcsolatok városi léptékű hálózata segítségével. Vizsgálatunk középpontjában a szél által kiváltott örvényleválás okozta szerkezeti rezgések állnak. A rendszert rugókból, csillapítóelemekből és tömegpontokból álló koncepcionális modell segítségével írjuk le. Ez a megközelítésmód lehetővé teszi nagy hálózatok gyors numerikus szimulációját, amely részletesebb mérnöki modellek esetében nem lehetséges. Véletlenszerűen generált épületcsoportok, és vízszintes rúdszerű kapcsolatokból kialakított háromszögelt hálózatok esetén vizsgáljuk a kapcsolatoknak, a bennük kialakított dilatációs hézagoknak és a hálózat méretének a hatását. Eredményeink azt mutatják, hogy a kapcsolatok jelentősen csökkentik a hálózat rezgéseit, különösen nagy hálózati méret esetén. A tanulmány célja, hogy kezdeti lépéseket tegyünk egy újszerű városfejlesztési modell előnyeinek feltárására.

Vibration of structurally connected high-rise buildings under wind force

2021 ◽  
Author(s):  
Mehmet Köhserli ◽  
Péter L. Várkonyi
Keyword(s):  
Structural Systems ◽  
Building Structures ◽  
Structural Behaviour ◽  
Wind Force ◽  
Building Stock ◽  
Existing Building ◽  
High Rise ◽  
Tall Structures ◽  
Simulation Results ◽  
Structural Networks

<p>Cities are organized around various underlying networks but building structures do not follow this trend. The isolation of structural systems causes difficulties in the case of tall structures. We investigate the possibility of improving structural behaviour by organizing buildings into urban-scale structural networks, with focus on vortex-induced vibration. We review our recent work, in which randomly generated collections of high-rise buildings were examined by numerical simulation using a conceptual model of the network composed of springs and point masses. Here we examine the behaviour of a realistic collection of buildings, generated by considering the existing building stock and urban fabric of Midtown Manhattan. The new simulation results suggest that connections among the buildings would enable the application of significantly softer bracing systems. This finding suggests that urban-scale structural networks is a promising direction of urban development.</p>

Models of network formation

2018 ◽  
Author(s):  
Mark Newman
Keyword(s):  
Degree Distribution ◽  
Network Formation ◽  
Preferential Attachment ◽  
Network Size ◽  
Large Network ◽  
Citation Networks ◽  
Airline Networks ◽  
Attachment Model ◽  
Delivery Networks

This chapter describes models of the growth or formation of networks, with a particular focus on preferential attachment models. It starts with a discussion of the classic preferential attachment model for citation networks introduced by Price, including a complete derivation of the degree distribution in the limit of large network size. Subsequent sections introduce the Barabasi-Albert model and various generalized preferential attachment models, including models with addition or removal of extra nodes or edges and models with nonlinear preferential attachment. Also discussed are node copying models and models in which networks are formed by optimization processes, such as delivery networks or airline networks.

scholarly journals Tower Crane Location Optimization for Heavy Unit Lifting in High-Rise Modular Construction

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 121
Author(s):  
Hosang Hyun ◽  
Moonseo Park ◽  
Dowan Lee ◽  
Jeonghoon Lee
Keyword(s):  
Low Cost ◽  
Modular Construction ◽  
Algorithm Optimization ◽  
Location Selection ◽  
Project Completion ◽  
High Rise ◽  
Tower Crane ◽  
Proposed Model ◽  
Study Results ◽  
Crane Selection

Modular construction, which involves unit production in factories and on-site work, has benefits such as low cost, high quality, and short duration, resulting from the controlled factory environment utilized. An efficient tower crane lifting plan ensures successful high-rise modular project completion. For improved efficiency, the lifting plan should minimize the reaching distance of the tower crane, because this distance directly affects the tower crane capacity, which is directly related to crane operation cost. In situations where units are lifted from trailers, the trailer-to-tower crane distance can have a significant impact on the tower crane operation efficiency. However, optimization of this distance to improve efficiency has not been sufficiently considered. This research proposes a genetic algorithm optimization model that suggests optimized tower crane and trailer locations. The case study results show that through the proposed model, the project manager can reflect the optimal location selection and optimal tower crane selection options with minimal cost.

scholarly journals The visual-landscape analysis during the integration of high-rise buildings within the historic urban environment

2018 ◽  
Vol 33 ◽  
pp. 01044
Author(s):  
Vera A. Akristiniy ◽  
Elena A. Dikova
Keyword(s):  
Urban Development ◽  
Urban Environment ◽  
Urban Landscape ◽  
Landscape Analysis ◽  
High Rise ◽  
Visual Landscape ◽  
Key Aspects ◽  
Typological Structure ◽  
The City ◽  
Information Database

The article is devoted to one of the types of urban planning studies - the visual-landscape analysis during the integration of high-rise buildings within the historic urban environment for the purposes of providing pre-design and design studies in terms of preserving the historical urban environment and the implementation of the reconstructional resource of the area. In the article formed and systematized the stages and methods of conducting the visual-landscape analysis taking into account the influence of high-rise buildings on objects of cultural heritage and valuable historical buildings of the city. Practical application of the visual-landscape analysis provides an opportunity to assess the influence of hypothetical location of high-rise buildings on the perception of a historically developed environment and optimal building parameters. The contents of the main stages in the conduct of the visual - landscape analysis and their key aspects, concerning the construction of predicted zones of visibility of the significant historically valuable urban development objects and hypothetically planned of the high-rise buildings are revealed. The obtained data are oriented to the successive development of the planning and typological structure of the city territory and preservation of the compositional influence of valuable fragments of the historical environment in the structure of the urban landscape. On their basis, an information database is formed to determine the permissible urban development parameters of the high-rise buildings for the preservation of the compositional integrity of the urban area.

scholarly journals Formation and maintenance of the territorial balance in the conditions of high-rise construction in the city

2018 ◽  
Vol 33 ◽  
pp. 01034
Author(s):  
Tatiana Kisel
Keyword(s):  
Urban Development ◽  
Urban Environment ◽  
Social Infrastructure ◽  
City Development ◽  
High Rise ◽  
The City

High-rise construction results in the need of planning of infrastructure facilities, taking into account the increase in loading, as high-rise construction allows to place considerably bigger number of residents in the limited territory. For this purpose it is necessary to estimate the required and actual level of providing the population with each particular type of the facilities of social infrastructure. The compliance of required and actual level of providing can be characterized as the territorial balance, while the discrepancy acts as the territorial imbalance. The article is devoted to the development of such instruments of planning of urban development, which will allow to create the qualitative urban environment, founded on the territorial balances. Namely, it is devoted to the calculation of level of providing the population with the facilities of social infrastructure, to the determination of level of the imbalance in absolute and relative units and also to the ranging of imbalances on urgency of their elimination. The size of the imbalance is of great importance for planning and realization of managerial influences from the executive authorities, operating the city development. In order to determine the urgency of realization of actions for the construction of facilities of social infrastructure it is offered to range the imbalances according to their size, having determined the deviation size from balance, which is so insignificant that it does not demand any managerial influences (it can be characterized as balance) and also the groups of the imbalances, differing in urgency of managerial influences, directed to the decrease and elimination of the revealed imbalance.

scholarly journals SOLF - A SOFTWARE DEVELOPMENT LIFECYCLE BASED ON GOLF

2020 ◽  
Author(s):  
CRS Kumar
Keyword(s):  
Software Development ◽  
Development Project ◽  
Difficulty Level ◽  
Golf Course ◽  
Skill Levels ◽  
Development Lifecycle ◽  
Proposed Model ◽  
Development Life Cycle ◽  
Software Development Lifecycle ◽  
Engineering Models

In the game of Golf, a player is challenged to take the minimum strokes to complete a round of 18 holes under varying playing conditions. Players use different clubs depending on their skill levels to achieve the desired distance while taking shots at the golf ball from the start (tee off) to the hole (pin). Unlike other games which have a standardized playing area, the terrain in a golf course comprises of various natural and manmade features viz. fairways, bunkers, trees, water bodies etc, which increase the difficulty level of the game and keep the players challenged.The game of golf has a fascinating similarity to a software development life cycle. If the holes on a golf course are considered akin to milestones in a development project then most of the Software Engineering models focus on software development in groups. Thus, we propose SOLF i.e Software Development Lifecycle model based on Golf, as a SDLC ideal for individuals or a small group of 2-3 developers. The proposed model is easy to comprehend, flexible and optimally adjustable in a dynamic environment.SOLF divides the project into 18 stages wherein each stage of the project will have 3 to 6 tasks which are required to be completed within a fixed timeline. The stages are managed by creating checklists at the start akin to the pre-shot routines in golf and the customer feedback is received on reaching each of the milestones similar to applause in the game of golf. Terrain of the golf course is reflected as risk list which are varying for each of the stages.SOLF achieves 10x speedup in software development and research projects as it creates an environment of challenges and drives the developer towards self excellence. It also inculcates a spirit of competition and sportsmanship by challenging the developers on various 'terrains' of development.

Convergence and approximate calculation of average degree under different network sizes for decreasing random birth-and-death networks

2018 ◽  
Vol 32 (15) ◽  
pp. 1850159
Author(s):  
Yin Long ◽  
Xiao-Jun Zhang ◽  
Kui Wang
Keyword(s):  
Analytical Solution ◽  
Numerical Method ◽  
Power Law ◽  
Approximate Calculation ◽  
Approximate Expression ◽  
Network Size ◽  
Average Degree ◽  
Large Network ◽  
Network Link ◽  
Theoretical Results

In this paper, convergence and approximate calculation of average degree under different network sizes for decreasing random birth-and-death networks (RBDNs) are studied. First, we find and demonstrate that the average degree is convergent in the form of power law. Meanwhile, we discover that the ratios of the back items to front items of convergent reminder are independent of network link number for large network size, and we theoretically prove that the limit of the ratio is a constant. Moreover, since it is difficult to calculate the analytical solution of the average degree for large network sizes, we adopt numerical method to obtain approximate expression of the average degree to approximate its analytical solution. Finally, simulations are presented to verify our theoretical results.

scholarly journals Accelerating Event Detection with DGCNN and FPGAs

Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1666
Author(s):  
Zhe Han ◽  
Jingfei Jiang ◽  
Linbo Qiao ◽  
Yong Dou ◽  
Jinwei Xu ◽  
...  
Keyword(s):  
Language Processing ◽  
Event Detection ◽  
Graphics Processing Unit ◽  
Network Size ◽  
Processing Unit ◽  
Sigmoid Function ◽  
Pipelined Architecture ◽  
Proposed Model ◽  
Field Programmable ◽  
Graphics Processing

Recently, Deep Neural Networks (DNNs) have been widely used in natural language processing. However, DNNs are often computation-intensive and memory-expensive. Therefore, deploying DNNs in the real world is very difficult. In order to solve this problem, we proposed a network model based on the dilate gated convolutional neural network, which is very hardware-friendly. We further expanded the word representations and depth of the network to improve the performance of the model. We replaced the Sigmoid function to make it more friendly for hardware computation without loss, and we quantized the network weights and activations to compress the network size. We then proposed the first FPGA (Field Programmable Gate Array)-based event detection accelerator based on the proposed model. The accelerator significantly reduced the latency with the fully pipelined architecture. We implemented the accelerator on the Xilinx XCKU115 FPGA. The experimental results show that our model obtains the highest F1-score of 84.6% in the ACE 2005 corpus. Meanwhile, the accelerator achieved 95.2 giga operations (GOP)/s and 13.4 GOPS/W in performance and energy efficiency, which is 17/158 times higher than the Graphics Processing Unit (GPU).

Scalings of first-return time for random walks on generalized and weighted transfractal networks

2019 ◽  
Vol 33 (26) ◽  
pp. 1950306
Author(s):  
Qin Liu ◽  
Weigang Sun ◽  
Suyu Liu
Keyword(s):  
Random Walks ◽  
Large Scale ◽  
Probability Generating Function ◽  
Return Time ◽  
Network Size ◽  
Large Network ◽  
Large Scale Network ◽  
Scale Network ◽  
The Mean ◽  
First Return Time

The first-return time (FRT) is an effective measurement of random walks. Presently, it has attracted considerable attention with a focus on its scalings with regard to network size. In this paper, we propose a family of generalized and weighted transfractal networks and obtain the scalings of the FRT for a prescribed initial hub node. By employing the self-similarity of our networks, we calculate the first and second moments of FRT by the probability generating function and obtain the scalings of the mean and variance of FRT with regard to network size. For a large network, the mean FRT scales with the network size at the sublinear rate. Further, the efficiency of random walks relates strongly with the weight factor. The smaller the weight, the better the efficiency bears. Finally, we show that the variance of FRT decreases with more number of initial nodes, implying that our method is more effective for large-scale network size and the estimation of the mean FRT is more reliable.

Chaotic Balanced State in a Model of Cortical Circuits

1998 ◽  
Vol 10 (6) ◽  
pp. 1321-1371 ◽  
Author(s):  
C. van Vreeswijk ◽  
H. Sompolinsky
Keyword(s):  
Cortical Neurons ◽  
Initial Conditions ◽  
Single Cells ◽  
Network Size ◽  
Short Time Scale ◽  
Strong Nonlinearity ◽  
Large Network ◽  
Wide Range ◽  
The Mean

The nature and origin of the temporal irregularity in the electrical activity of cortical neurons in vivo are not well understood. We consider the hypothesis that this irregularity is due to a balance of excitatory and inhibitory currents into the cortical cells. We study a network model with excitatory and inhibitory populations of simple binary units. The internal feedback is mediated by relatively large synaptic strengths, so that the magnitude of the total excitatory and inhibitory feedback is much larger than the neuronal threshold. The connectivity is random and sparse. The mean number of connections per unit is large, though small compared to the total number of cells in the network. The network also receives a large, temporally regular input from external sources. We present an analytical solution of the mean-field theory of this model, which is exact in the limit of large network size. This theory reveals a new cooperative stationary state of large networks, which we term a balanced state. In this state, a balance between the excitatory and inhibitory inputs emerges dynamically for a wide range of parameters, resulting in a net input whose temporal fluctuations are of the same order as its mean. The internal synaptic inputs act as a strong negative feedback, which linearizes the population responses to the external drive despite the strong nonlinearity of the individual cells. This feedback also greatly stabilizes the system's state and enables it to track a time-dependent input on time scales much shorter than the time constant of a single cell. The spatiotemporal statistics of the balanced state are calculated. It is shown that the autocorrelations decay on a short time scale, yielding an approximate Poissonian temporal statistics. The activity levels of single cells are broadly distributed, and their distribution exhibits a skewed shape with a long power-law tail. The chaotic nature of the balanced state is revealed by showing that the evolution of the microscopic state of the network is extremely sensitive to small deviations in its initial conditions. The balanced state generated by the sparse, strong connections is an asynchronous chaotic state. It is accompanied by weak spatial cross-correlations, the strength of which vanishes in the limit of large network size. This is in contrast to the synchronized chaotic states exhibited by more conventional network models with high connectivity of weak synapses.

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