• Title/Summary/Keyword: City models

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Development and validation of a computational multibody model of the elbow joint

  • Rahman, Munsur;Cil, Akin;Johnson, Michael;Lu, Yunkai;Guess, Trent M.
    • Advances in biomechanics and applications
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    • v.1 no.3
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    • pp.169-185
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    • 2014
  • Computational multibody models of the elbow can provide a versatile tool to study joint mechanics, cartilage loading, ligament function and the effects of joint trauma and orthopaedic repair. An efficiently developed computational model can assist surgeons and other investigators in the design and evaluation of treatments for elbow injuries, and contribute to improvements in patient care. The purpose of this study was to develop an anatomically correct elbow joint model and validate the model against experimental data. The elbow model was constrained by multiple bundles of non-linear ligaments, three-dimensional deformable contacts between articulating geometries, and applied external loads. The developed anatomical computational models of the joint can then be incorporated into neuro-musculoskeletal models within a multibody framework. In the approach presented here, volume images of two cadaver elbows were generated by computed tomography (CT) and one elbow by magnetic resonance imaging (MRI) to construct the three-dimensional bone geometries for the model. The ligaments and triceps tendon were represented with non-linear spring-damper elements as a function of stiffness, ligament length and ligament zero-load length. Articular cartilage was represented as uniform thickness solids that allowed prediction of compliant contact forces. As a final step, the subject specific model was validated by comparing predicted kinematics and triceps tendon forces to experimentally obtained data of the identically loaded cadaver elbow. The maximum root mean square (RMS) error between the predicted and measured kinematics during the complete testing cycle was 4.9 mm medial-lateral translational of the radius relative to the humerus (for Specimen 2 in this study) and 5.30 internal-external rotation of the radius relative to the humerus (for Specimen 3 in this study). The maximum RMS error for triceps tendon force was 7.6 N (for Specimen 3).

Using neural networks to model and predict amplitude dependent damping in buildings

  • Li, Q.S.;Liu, D.K.;Fang, J.Q.;Jeary, A.P.;Wong, C.K.
    • Wind and Structures
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    • v.2 no.1
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    • pp.25-40
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    • 1999
  • In this paper, artificial neural networks, a new kind of intelligent method, are employed to model and predict amplitude dependent damping in buildings based on our full-scale measurements of buildings. The modelling method and procedure using neural networks to model the damping are studied. Comparative analysis of different neural network models of damping, which includes multi-layer perception network (MLP), recurrent neural network, and general regression neural network (GRNN), is performed and discussed in detail. The performances of the models are evaluated and discussed by tests and predictions including self-test, "one-lag" prediction and "multi-lag" prediction of the damping values at high amplitude levels. The established models of damping are used to predict the damping in the following three ways : (1) the model is established by part of the data measured from one building and is used to predict the another part of damping values which are always difficult to obtain from field measurements : the values at the high amplitude level. (2) The model is established by the damping data measured from one building and is used to predict the variation curve of damping for another building. And (3) the model is established by the data measured from more than one buildings and is used to predict the variation curve of damping for another building. The prediction results are discussed.

CROSS SECTIONAL ANALYSIS OF RESIDENTIAL WATER CONSUMPTION IN THE CITY OF RIYADH

  • Taher, Saud;Alsaati, Adnan
    • Water Engineering Research
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    • v.3 no.4
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    • pp.269-278
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    • 2002
  • A cross sectional analysis for residential water demand was conducted to help understand and explain the spatial and temporal variations in per capita water use in the rapidly growing city of Riyadh, Saudi Arabia. The analysis was based on data previously collected from May 1983 to June 1984. 195 randomly selected households were distributed to three groups according to house condition, household income level, and social and cultural factors. The generated models using stepwise multiple regression indicated that plot size and number of males, females and children are the most significant independent variables. Although, coefficients of determination achieved for most of the developed models were low (0.2-0.5), the independent variables could still explain a part of the variations fur such a complex social and cultural structure.

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Mapping Airbnb prices in a small city: A geographically weighted approach for Macau tourist attractions (작은 도시에 에어비앤비 가격지도: 지리가중접근법 활용한 마카오 관광지에 대한 분석)

  • Tang, Honian;Hong, Insu;Yoo, Changsok
    • Proceedings of the Korea Contents Association Conference
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    • 2019.05a
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    • pp.211-212
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    • 2019
  • The objectives of this research are to test the utility of semiparametric geographically weighted regression (SGWR, a spatial analysis method) in the small-scale urban sample, and to understand the geographic patterns of provision and pricing of sharing economy based accommodations in the tourist city. This paper focused on how network distance to heritage site, to casino, residential unit prices and other five attribute categories determine Airbnb price in Macau SAR, China. Findings show that SGWR models outperformed OLS models. Moreover, comparing with heritage sites, casinos are the stronger factors to drive up Airbnb (including hostels) rooms' provision and their prices; and residential unit prices are not related with the Airbnb price in the attraction clusters in Macau. This research showed a little example for the applications of SGWR in the small city, and for the analysis of online marketplace data as new urban study material. Practically, this study provides some scientific evidence for hosts, guests, urban planners, and policymakers' decision making in Macau.

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A study on the u-City hazard mitigation services in KT (KT u-City 방재 서비스 모델에 관한 연구)

  • Lee, Bum-Gyo;Kim, Hyung-Woo
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.365-368
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    • 2008
  • The concept of "ubiquitous" has become the top issue of the 21st century communications field within the past years. u-City has become the new city paradigm with the convergence of city planning and ubiquitous communication technologies and services. Starting from 2004, KT has collaborated with the Korean government to develop comfortable, convenient, pleasant, safe, and healthy IT technology based u-City focusing on; balanced development, value creation, and improved standard of living within the region. Presently the term, "hazard mitigation services" lacks a clear definition due to its varying applications by different local agencies and has caused confusion. Therefore, this report will clarify and define u-City hazard mitigation services currently proposed to the local agencies as well as services currently in effect. Additionally, the report will introduce hazard mitigation service models feasible by KT.

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A Study on Building up the Portal Service to Support Low-Carbon City Planning in Korea (저탄소도시계획지원을 위한 포털서비스의 구축방향)

  • Kim, Han-Jun;Choi, Hong-Jun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.5
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    • pp.2465-2473
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    • 2013
  • This study reviews planning support systems (PSS) in the context of the development processes of urban models(focusing on Land-Use Transport Models, LUTM) and Geographic Information Systems (GIS), both of which are key components of PSS supporting spatial plannings like urban and regional planning. It also explores changing planning environments like increased demands of citizen participation, especially in the environmental sector like global warming, and intensified development of Information technologies based on Internet and mobile networks. As a conclusion this study proposes a prototype of portal service to support low-carbon city planning to mitigate the greenhouse gas as an alternative to supplement or reinforce PSS, reflecting the changing planning environments.

Extracting Building Geomety from BIM for 3-D City Model (BIM으로부터 가상도시 구축용 건축물정보의 추출)

  • Goh, Il-Du;Choi, Joong-Hyun;Kim, E-Doo;Jeong, Yeon-Suk;Lee, Jae-Min
    • Spatial Information Research
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    • v.16 no.2
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    • pp.249-261
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    • 2008
  • This study proposes a method for acquiring and managing basic information on building, which is continuously updated through construction and re-construction, in order to implement 3D-GIS based on geometric shape information and building information. First of all, distinctions between BIM and GIS information models are described, and then an overview of CityGML for virtual city and its Level of Detail are introduced. At last, a prototype for extracting building geometry from BIM data in accordance with CityGML is presented for demonstration. By using IFC data from BIM, this approach enables a lot of firms and contractors in building industry to utilize their 2D/3D, data on sites and buildings, and also to save many effects for generating exterior and interior building models which are inevitable for implementing National GIS.

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A Spatial Analysis of the Causal Factors Influencing China's Air Pollution

  • Kim, Yoomi;Tanaka, Katsuya;Zhang, Xinxin
    • Asian Journal of Atmospheric Environment
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    • v.11 no.3
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    • pp.194-201
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    • 2017
  • This study investigates the factors that affect China's air pollution using city-level panel data and spatial econometric models. We address three air pollutants ($PM_{10}$, $SO_2$, and $NO_2$) present in 30 cities in China between 2004-2012 using global OLS and spatial models. To develop the spatial econometric analysis, we create a spatial weights matrix to define spatial patterns based on two neighborhood criteria - the queen contiguity and k nearest neighbors. The results show that the estimated coefficients are relatively consistent across different spatial weight criteria. The OLS models indicate that the effect of green spaces is statistically significant in decreasing the concentrations of all air pollutants. In the $PM_{10}$ and $SO_2$ analyses, the OLS models find that the number of buses and population density are also positively related to a reduction in the concentration of air pollutants. In addition, an increase in the temperature and the presence of secondary industries increase $SO_2$ and $NO_2$ concentrations, respectively. All spatial models capture a positive and significant effect of green spaces on reducing the concentration of each air pollutant. Our results suggest that green spaces in cities should receive priority consideration in local planning aimed at sustainable development. Furthermore, policymakers need to be able to discern the differences among pollutants when establishing environmental policies.

Where and Why? A Novel Approach for Prioritizing Implementation Points of Public CCTVs using Urban Big Data

  • Ji Hye Park;Daehwan Kim;Keon Chul Park
    • Journal of Internet Computing and Services
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    • v.24 no.5
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    • pp.97-106
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    • 2023
  • Citizens' demand for public CCTVs continues to rise, along with an increase in variouscrimes and social problems in cities. In line with the needs of citizens, the Seoul Metropolitan Government began installing CCTV cameras in 2010, and the number of new installations has increased by over 10% each year. As the large surveillance system represents a substantial budget item for the city, decision-making on location selection should be guided by reasonable standards. The purpose of this study is to improve the existing related models(such as public CCTV priority location analysis manuals) to establish the methodology foranalyzing priority regions ofSeoul-type public CCTVs and propose new mid- to long-term installation goals. Additionally, using the improved methodology, we determine the CCTV priority status of 25 autonomous districts across Seoul and calculate the goals. Through its results, this study suggests improvements to existing models by addressing their limitations, such as the sustainability of input data, the conversion of existing general-purpose models to urban models, and the expansion of basic local government-level models to metropolitan government levels. The results can also be applied to other metropolitan areas and are used by the Seoul Metropolitan Government in its CCTV operation policy

YSIM for City and Regional Planning ("도시 및 지역계획 지원을 위한 YSIM(Yangsuk's SIMulation)")

  • 강양석
    • Journal of Korean Society of Transportation
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    • v.5 no.1
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    • pp.59-74
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    • 1987
  • A prediction is an indispensable element to research of Social Science, especially in Regional planning, City planning, and Transportation planning. Since 1930s, varieties of prediction methods have been developed. In the 1980s, numerical models have been used by high-developed computers. even though the numerical models can be figured mathematically, it could not be applied practically due to it's expertness and complicateness. And even professional planners often can not use their ideas which are valuable experiences in prediction process, because they are not knowledgable for numerical models. The YSIM developed by author, is available as follows. i)Numerical modeling of professional experiences ii)Providing a foundation of large-scale model iii) Understanding of research object structure The YSIM make use of matrix to identify the system structure which is similar to the Cross Impact Method. To evaluated the YSIM availabilities, it is compared with the early developed methodologies such as KSIM, QSIM, and SPIN. As the result, it was confirmed that YSIM was more accurate in the prediction. The algorithms in YSIM is programmed for use of PCs.

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