A Modified Gravity p-Median Model for Optimizing Facility Locations

2018 ◽  
Vol 6 (5) ◽  
pp. 421-434 ◽  
Author(s):  
Zhuolin Tao ◽  
Qingjing Zheng ◽  
Hui Kong
Keyword(s):  
Modified Gravity ◽  
Distance Decay ◽  
Decay Parameter ◽  
Distance Threshold ◽  
Facility Locations ◽  
Spatial Equity ◽  
Average Travel Time ◽  
Tertiary Hospitals ◽  
The Difference

AbstractThe gravityp-median model is an important improvement to the widely-usedp-median model. However, there is still a debate on its validity in empirical applications. Previous studies even doubt the significance of the gravityp-median model. Using a case study of tertiary hospitals in Shenzhen, China, this study re-examines the difference between the gravityp-median model with thep-median model, by decomposing the difference between the two models into gravity rule and variant attraction. This study also proposes a modified gravityp-median model by incorporating a distance threshold. The empirical results support the validity of the gravityp-median model, and also reveal that only when the attractions of candidate facility locations are variable will the gravityp-median model lead to different results with thep-median model. The difference between the modified gravityp-median model and the gravityp-median model is also examined. Moreover, the impacts of the distance-decay parameter and distance threshold on solutions are investigated. Results indicate that a larger distance-decay parameter tends to result in a more dispersed distribution of optimal facilities and a smaller average travel time, and a smaller distance threshold can better promote the spatial equity of facilities. The proposed method can also be applied in studies of other types of facilities or in other areas.

scholarly journals Modelling walking accessibility: A case study of Ljubljana, Slovenia

2019 ◽  
Vol 27 (4) ◽  
pp. 194-206
Author(s):  
Jernej Tiran ◽  
Mitja Lakner ◽  
Samo Drobne
Keyword(s):  
Distance Decay ◽  
Integrated Network ◽  
Distance Threshold ◽  
Transport Distance ◽  
Fixed Distance ◽  
Different Types ◽  
Best Fitting ◽  
Retail Services ◽  
The City

Abstract Walkable access is recognised as one of the most important factors for deciding to walk instead of using other modes of transport. Distance has been less accurately taken into consideration in previous walking accessibility measures, however, as they are often based on an isotropic approach or on a fixed distance threshold. The objective of this paper is to present a method of modelling continuous walking accessibility to different amenities in a city, with an integrated network-based and distance-decay approach, applied to a case study of the city of Ljubljana, Slovenia. The approach is based on a web survey to obtain data on acceptable walking distances to different types of amenities. Several distance decay functions were analysed for each type of amenity from the cumulative frequency of responses. The best fitting functions were used to model the walking accessibility surfaces for individual amenities in the network, representing five domains (retail, services, recreation, education and transportation) and an overall walking accessibility index. Despite certain limitations and a further need to assess the validity of the methods, our distance-decay network-based approach is more accurate than the isotropic or even network-based modelling of walking distances in continuous or threshold approaches, as it enables the researcher to take into account the differences in propensities to walk to different amenities. The results can be used by city authorities and planners for implementing actions to improve walking accessibility in the most problematic areas.

scholarly journals Hierarchical two-step floating catchment area (2SFCA) method: measuring the spatial accessibility to hierarchical healthcare facilities in Shenzhen, China

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Zhuolin Tao ◽  
Yang Cheng ◽  
Jixiang Liu
Keyword(s):  
Local Governments ◽  
Catchment Area ◽  
Spatial Accessibility ◽  
Spatial Disparity ◽  
Traditional Methods ◽  
Healthcare Facilities ◽  
Spatial Equity ◽  
Tertiary Hospitals ◽  
Different Levels

Abstract Background Spatial accessibility to healthcare facilities has drawn much attention in health geography. In China, central and local governments have aimed to develop a well-organized hierarchical system of healthcare facilities in recent years. However, few studies have focused on the measurement of healthcare accessibility in a hierarchical service delivery system, which is crucial for the assessment and implementation of such strategies. Methods Based on recent improvements in 2SFCA (two-step floating catchment area) method, this study aims to propose a Hierarchical 2SFCA (H2SFCA) method for measuring spatial accessibility to hierarchical facilities. The method considers the varied catchment area sizes, distance decay effects, and transport modes for facilities at various levels. Moreover, both the relative and absolute distance effects are incorporated into the accessibility measurement. Results The method is applied and tested in a case study of hierarchical healthcare facilities in Shenzhen, China. The results reveal that the general spatial accessibility to hierarchical healthcare facilities in Shenzhen is unevenly distributed and concentrated. The disparity of general accessibility is largely caused by the concentrated distribution of tertiary hospitals. For facilities at higher levels, average accessibility of demanders is higher, but there are also larger disparities in spatial accessibility. The comparison between H2SFCA and traditional methods reveals that traditional methods underestimate the spatial disparity of accessibility, which may lead to biased suggestions for policy making. Conclusions The results suggest that the supply of healthcare resources at primary facilities is far from sufficient. To improve the spatial equity in spatial accessibility to hierarchical healthcare facilities, various actions are needed at different levels. The proposed H2SFCA method contributes to the modelling of spatial accessibility to hierarchical healthcare facilities in China and similar environments where the referral system has not been well designed. It can also act as the foundation for developing more comprehensive measures in future studies.

EVALUASI PROYEKSI DEMAND BARANG DAN PENUMPANG PELABUHAN DI PROVINSI MALUKU

2019 ◽  
Vol 19 (2) ◽  
pp. 101-110
Author(s):  
Adrian Firdaus ◽  
M. Dwi Yoga Sutanto ◽  
Rajin Sihombing ◽  
M. Weldy Hermawan
Keyword(s):  
Time Series ◽  
Projection Method ◽  
Development Plan ◽  
Master Plan ◽  
Port Development ◽  
Loading And Unloading ◽  
The Difference ◽  
Existing Data

Abstract Every port in Indonesia must have a Port Master Plan that contains an integrated port development plan. This study discusses one important aspect in the preparation of the Port Master Plan, namely the projected movement of goods and passengers, which can be used as a reference in determining the need for facilities at each stage of port development. The case study was conducted at a port located in a district in Maluku Province and aims to evaluate the analysis of projected demand for goods and passengers occurring at the port. The projection method used is time series and econometric projection. The projection results are then compared with the existing data in 2018. The results of this study show that the econometric projection gives adequate results in predicting loading and unloading activities as well as the number of passenger arrival and departure in 2018. This is indicated by the difference in the percentage of projection results towards the existing data, which is smaller than 10%. Whereas for loading and unloading activities, time series projections with logarithmic trends give better results than econometric projections. Keywords: port, port master plan, port development, unloading activities  Abstrak Setiap pelabuhan di Indonesia harus memiliki sebuah Rencana Induk Pelabuhan yang memuat rencana pengem-bangan pelabuhan secara terpadu. Studi ini membahas salah satu aspek penting dalam penyusunan Rencana Induk Pelabuhan, yaitu proyeksi pergerakan barang dan penumpang, yang dapat dipakai sebagai acuan dalam penentuan kebutuhan fasilitas di setiap tahap pengembangan pelabuhan. Studi kasus dilakukan pada sebuah pelabuhan yang terletak di sebuah kabupaten di Provinsi Maluku dan bertujuan untuk melakukan evaluasi ter-hadap analisis proyeksi demand barang dan penumpang yang terjadi di pelabuhan tersebut. Metode proyeksi yang dipakai adalah proyeksi deret waktu dan ekonometrik. Hasil proyeksi selanjutnya dibandingkan dengan data eksisting tahun 2018. Hasil studi ini menunjukkan bahwa proyeksi ekonometrik memberikan hasil yang cukup baik dalam memprediksi aktivitas bongkar barang serta jumlah penumpang naik dan turun di tahun 2018. Hal ini diindikasikan dengan selisih persentase hasil proyeksi terhadap data eksisting yang lebih kecil dari 10%. Sedangkan untuk aktivitas muat barang, proyeksi deret waktu dengan tren logaritmik memberikan hasil yang lebih baik daripada proyeksi ekonometrik. Kata-kata kunci: pelabuhan, rencana induk pelabuhan, pengembangan pelauhan, aktivitas bongkar barang

scholarly journals Using a Process Approach to Pandemic Planning: A Case Study

2021 ◽  
Vol 11 (9) ◽  
pp. 4121
Author(s):  
Hana Tomaskova ◽  
Erfan Babaee Tirkolaee
Keyword(s):  
Process Model ◽  
Process Mining ◽  
Process Approach ◽  
Research Topic ◽  
Future Research ◽  
Critical Situation ◽  
Pandemic Planning ◽  
The Difference ◽  
Smart Technologies

The purpose of this article was to demonstrate the difference between a pandemic plan’s textual prescription and its effective processing using graphical notation. Before creating a case study of the Business Process Model and Notation (BPMN) of the Czech Republic’s pandemic plan, we conducted a systematic review of the process approach in pandemic planning and a document analysis of relevant public documents. The authors emphasized the opacity of hundreds of pages of text records in an explanatory case study and demonstrated the effectiveness of the process approach in reengineering and improving the response to such a critical situation. A potential extension to the automation and involvement of SMART technologies or process optimization through process mining techniques is presented as a future research topic.

scholarly journals E-learning-Oriented Software Architecture Design and Case Study

2015 ◽  
Vol 10 (4) ◽  
pp. 59
Author(s):  
Peng Lu ◽  
Xiao Cong ◽  
Dongdai Zhou
Keyword(s):  
Software Architecture ◽  
Building Blocks ◽  
Domain Model ◽  
Learning System ◽  
Application Framework ◽  
Component Library ◽  
E Learning ◽  
The Difference ◽  
High Level

Nowadays, E-learning system has been widely applied to practical teaching. It was favored by people for its characterized course arrangement and flexible learning schedule. However, the system does have some problems in the process of application such as the functions of single software are not diversified enough to satisfy the requirements in teaching completely. In order to cater more applications in the teaching process, it is necessary to integrate functions from different systems. But the difference in developing techniques and the inflexibility in design makes it difficult to implement. The major reason of these problems is the lack of fine software architecture. In this article, we build domain model and component model of E-learning system and components integration method on the basis of WebService. And we proposed an abstract framework of E-learning which could express the semantic relationship among components and realize high level reusable on the basis of informationized teaching mode. On this foundation, we form an E-learning oriented layering software architecture contain component library layer, application framework layer and application layer. Moreover, the system contains layer division multiplexing and was not built upon developing language and tools. Under the help of the software architecture, we could build characterized E-learning system flexibly like building blocks through framework selection, component assembling and replacement. In addition, we exemplify how to build concrete E-learning system on the basis of this software architecture.

Magnetotelluric static shift: Estimation and removal using the cokriging method

Geophysics ◽  
2007 ◽  
Vol 72 (1) ◽  
pp. F25-F34 ◽  
Author(s):  
Benoit Tournerie ◽  
Michel Chouteau ◽  
Denis Marcotte
Keyword(s):  
Apparent Resistivity ◽  
A Priori ◽  
Shift Factor ◽  
Static Shift ◽  
Geostatistical Model ◽  
Data Set ◽  
Resistivity Sounding ◽  
The Difference ◽  
Cross Variogram

We present and test a new method to correct for the static shift affecting magnetotelluric (MT) apparent resistivity sounding curves. We use geostatistical analysis of apparent resistivity and phase data for selected periods. For each period, we first estimate and model the experimental variograms and cross variogram between phase and apparent resistivity. We then use the geostatistical model to estimate, by cokriging, the corrected apparent resistivities using the measured phases and apparent resistivities. The static shift factor is obtained as the difference between the logarithm of the corrected and measured apparent resistivities. We retain as final static shift estimates the ones for the period displaying the best correlation with the estimates at all periods. We present a 3D synthetic case study showing that the static shift is retrieved quite precisely when the static shift factors are uniformly distributed around zero. If the static shift distribution has a nonzero mean, we obtained best results when an apparent resistivity data subset can be identified a priori as unaffected by static shift and cokriging is done using only this subset. The method has been successfully tested on the synthetic COPROD-2S2 2D MT data set and on a 3D-survey data set from Las Cañadas Caldera (Tenerife, Canary Islands) severely affected by static shift.

scholarly journals Forest biomass and wood consumption In the lower course of the Amazon: a case study of rhe Urubueua Island

1999 ◽  
Vol 29 (1) ◽  
pp. 79-79 ◽  
Author(s):  
Akio TSUCHIYA ◽  
Mario HIRAOKA
Keyword(s):  
Water Stress ◽  
Forest Structure ◽  
Forest Biomass ◽  
Human Intervention ◽  
Terra Firme ◽  
Wood Volume ◽  
The Difference ◽  
Várzea Forests ◽  
Wood Consumption

Várzea and terra-firme forests in the lower course of the Amazon were compared in terms of forest structure, wood volume increments and forest biomass. The wood volume of várzea forests was smaller than that of terra-firme forests, particularly when severe human intervention such as the cultivation of açaí palm occurred. The difference was even greater in the forest weight comparison because of the lower wood density of várzea trees. These trees are not directly influenced by water stress during the dry season, while late wood with a high density is formed in the terra-firme trees. The annual forest disappearance area due to firewood for tile factories was estimated to be about 276 ha on the island investigated, which had an area of 36,200 ha. Assuming that the forests are rotatively cultivated every 25 to 30 years, the total deforestation area is 6,870-6,948 ha in 25 years and 8,244~8,337 ha in 30 years. This result means that the balance between forest biomass and utilization is not in crisis, however, this balance might be lost as long as substitutive energy such as electricity is not supplied.

ASSESSMENT OF INDOOR ENVIRONMENTAL QUALITY AND OCCURRENCE OF SICK BUILDING SYNDROME IN SMALL OFFICES IN PENANG, MALAYSIA

2015 ◽  
Vol 75 (5) ◽  
Author(s):  
Ang Qiu Mei ◽  
Md Azree Othuman Mydin
Keyword(s):  
Environmental Quality ◽  
Sick Building Syndrome ◽  
Quality Measurement ◽  
Comfort Level ◽  
Working Environment ◽  
Indoor Environmental Quality ◽  
Sick Building ◽  
The Difference

This study was done to investigate the relationship between indoor environmental quality and prevalence of Sick Building Syndrome in six small offices inPenangIsland. Indoor environmental quality measurement was conducted according to relevant standards. There are totally Sixty workers were selected to participate in an electronic questionnaire survey. Questionnaire was used to record the comfort level of respondents in the case studies and level of sick building syndrome faced by respondents. Through indoor environmental quality measurement, it is found that most of the offices facing the lighting and noise problem. The result from the questionnaire shows that in overall, the occupants satisfy with their working environment in term of indoor environmental quality although the result also shows the opinions of occupants on dissatisfaction on certain indoor environmental parameter according to case study. The study also found that most of the occupants feel drowsy and fatigue when they work within the offices. Besides, due to the difference of the indoor environmental quality of the buildings, the occupants are suffered from different symptoms of the sick building syndrome.

scholarly journals Rethinking Streets for Physical Distancing

2021 ◽  
Author(s):  
Marc Schlossberg ◽  
◽  
Rebecca Lewis ◽  
Aliza Whalen ◽  
Clare Haley ◽  
...  
Keyword(s):  
Best Practices ◽  
Case Studies ◽  
Evidence Based ◽  
The Third ◽  
Spatial Equity ◽  
Outdoor Space ◽  
Primary Output ◽  
Page Book

This report summarizes the primary output of this project, a book of COVID-era street reconfiguration case studies called Rethinking Streets During COVID-19: An Evidence-Based Guide to 25 Quick Redesigns for Physical Distancing, Public Use, and Spatial Equity. COVID-era needs have accelerated the process that many communities use to make street transformations due to: a need to remain physically distanced from others outside our immediate household; a need for more outdoor space close to home in every part of every community to access and enjoy; a need for more space to provide efficient mobility for essential workers in particular; and a need for more space for local businesses as they try to remain open safely. This project is the third in a series of NITC-supported case study books on best practices in street reconfigurations for more active, sustainable, and in this case, COVID-supportive uses. The full, 154-page book is available for free download from the National Institute for Transportation and Communities (NITC).

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