• Title/Summary/Keyword: Urban resilience

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Natural Frequency Analysis of Sleeper Floating Track System using Modal Test Technique (모달시험기법을 이용한 침목플로팅궤도의 고유진동수 분석)

  • Jung-Youl Choi
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.3
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    • pp.833-838
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    • 2024
  • The urban railway sleeper floating track(STEDEF) is a structure that structurally separates the sleepers and the concrete bed using sleeper boots and resilience pads to reduce vibration transmitted to the concrete bed. Recently, the resilience pads of sleeper floating tracks that have been in use for more than 20 years are deteriorating. Accordingly, in order to evaluate the performance of the resilience pad, a static spring stiffness test is being performed after extracting the resilience pad. This evaluation technique is performed after replacing the resilience pad in use. However, the track natural frequency can change depending on the resilience pad spring stiffness and the uplift and subsidence of the concrete bed. In this study, modal testing technique was used to evaluate the track natural frequency. For this purpose, the sleeper boots material, resilience pad spring stiffness, and track natural frequency according to concrete bed uplift and subsidence were measured using modal tests at a laboratory scale. It was analyzed that the natural frequency of the sleeper floating track was directly affected by changes in the spring stiffness of the resilience pad. In addition, the change in natural frequency due to the uplift and subsidence of the concrete bed was also found to be large. Therefore, it is believed that the modal test technique presented in this study can be used to evaluate the resilience pad deterioration and voided sleepers.

Theoretical Approaches to Regional Transformation: Path Dependence Theory and Regional Resilience Concept (경로의존론과 지역회복력 개념: 지역격차에 대한 새로운 이론적 접근)

  • Shin, Dong-Ho
    • Journal of the Economic Geographical Society of Korea
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    • v.20 no.1
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    • pp.70-83
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    • 2017
  • Traditionally, economic growth has been uneven over the space. It has also been true for the recovery from social and economic crisis in old industrial areas of the advanced economies. Even if many of such old industrial areas were seriously affected by de-industrialization, some areas have been showing progress, while others have not been so. While interpreting this phenomenon used to be a key issue in economics, main stream liberal economic theorists' explanation was uneven distribution of economic resources, such as raw materials, labour and money. However, some revolutionary economic theorists have brought in the concept of "history" in explaining the phenomenon. Path dependence theorists, for example, interpretate the emergence of different growth paths with the concept of historical accidents. This contrasts to the recent argument of the group of scholars suggesting the concept of "regional resilience," who argue that uneven growth and different growth paths are originated from different regional resilience. This paper introduces the backgrounds, characteristics and utilities of the two theories: path dependence theory and the concept of regional resilience.

Design Strategies to Enhance Resilience of Ecosystem Services in Urban Wetland - Using System Thinking - (생태계서비스 회복력 향상을 위한 도시 습지 설계 전략 - 시스템 사고를 활용하여 -)

  • You, Soo-jin;Ham, Eun-Kyung;Lee, Jung-a;Cho, Dong-Gil;Chon, Jin-hyung
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.20 no.4
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    • pp.43-61
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    • 2017
  • The wetlands are facing environmental changes such as desiccation that occurs with the passage of time and reduced ecosystem services from wetlands in the city. In order to maintain the ecosystem services provided by wetlands in urban areas, a system thinking about the trade-off phenomenon of ecosystem services occurring as the wetlands undergo environmental changes is needed. Therefore, the purpose of this study is to develop strategies for wetland design using system thinking approach to enhance the resilience of ecosystem services degraded by the desiccation of wetlands and other disturbances. The objectives of this study include the system boundary and variables. Second, analyzing the dynamics of wetland design strategy. Third, it analyzes the trade-off phenomenon of ecosystem services in terms of the hydrology, hydric soil, and plants strategies to mitigate these effects. Fourth, wetland basic design to improve the resilience of ecosystem services. A wetland in Abuk-Mountain Neighborhood Park, Miryang-si, Gyeongsangnam-do, has been selected as a case study. Causal loop diagrams(CLDs) are used to analyze feedback in the wetland regime. In summary, hydrology, hydric soil, and plants is suggested as system boundaries to design plan. Design strategies for the wetland focused on robustness, redundancy, rapidity, and resourcefulness as a result of CLD analysis are first proposed in order to effectively maintain the wetland regime over the long term. Secondly, in a section related to hydrology, the CLD results show the trade-offs between provisioning-cultural services and regulating services. In order to control these services, a "water cycling system" has been implemented due to its strength in terms of robustness. The CLDs for hydric soil showed the trade-offs between regulating services and supporting services. An "installation of storm drainage for maintaining water levels" was selected due to the strength offered in terms of redundancy and rapidity. The CLDs for plants showed the trade-offs between provisioning - cultural services and regulating services. In order to control the strategic points, the "planting of indigenous vegetation" was suggested given the strength in terms of redundancy. In this study, a wetland design method is proposed that can improve the resilience of wetland ecosystem services by analyzing the dynamics overtime. The results of this research can theoretically be applied to help restore ecosystem services in wetlands using ecological landscape design. In addition, this study will contribute to reducing maintenance costs by improving wetland resilience.

Reliability Evaluation of Resilient Safety Culture Using Fault Tree Analysis

  • Garg, Arun;Tonmoy, Fahim;Mohamed, Sherif
    • International conference on construction engineering and project management
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    • 2020.12a
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    • pp.303-312
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    • 2020
  • Safety culture is a collection of the beliefs, perceptions and values that employees share in relation to risks within an organisation. On the other hand, a resilient safety culture (RSC) means a culture with readiness of the organisation to respond effectively under stress, bounce back from shocks and continuously learn from them. RSC helps organisations to protect their interest which can be attributed to behavioural, psychological and managerial capabilities of the organization. Quantification of the degree of resilience in an organisation's safety culture can provide insights about the strong and weak links of the organisation's overall health and safety situation by identifying potential causes of system or sub-system failure. One of the major challenges of quantification of RSC is that the attributes that determine RSC need to be measured through constructs and indicators which are complex and often interrelated. In this paper, we address this challenge by applying a fault tree analysis (FTA) technique which can help analyse complex and interrelated constructs and indicators. The fault tree model of RSC is used to evaluate resilience levels of two organisations with remote and urban locations in order to demonstrate the failure path of the weak links in the RSC model.

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A study for management strategies through the spatial analysis of damaged Jeongmaek in South Korea (정맥 훼손현황의 공간적 분석을 통한 관리방향 제안 연구)

  • Lim, No Ol;Lee, Sang-WooK;Sung, Hyun Chan
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.27 no.5
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    • pp.27-40
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    • 2024
  • Mountain ranges are crucial not only as habitats for biodiversity but also as sources of diverse ecosystem services essential to human well-being. In South Korea, the Baekdudaegan mountain range is protected for its natural and cultural significance. However, the subsidiary mountain ranges, known as Jeongmaeks, remain vulnerable to urbanization due to inadequate protection and management plans. This study aims to assess the impact of urbanization on Jeongmaek areas, utilizing the 'Environmental Impact Assessment Guideline for Baekdudaegan and Jeongmaek' to inform future management strategies. Damage was identified urbanized areas in land cover maps and EIA target areas, and loss of ecological connectivity. The results indicate that the Jeongmaeks near densely populated regions, such as the Seoul Metropolitan Area (Hannam and Hankbuk Jeongmaek), have suffered significant fragmentation, primarily due to road and rail construction. These areas should be managed as recreational zones, integrating natural parks and entertainment facilities to promote sustainable use of natural resources. Conversely, the Jeongmaeks located both near and further from urban centers, such as Nakdong and Naknam Jeongmaek, exhibit a mix of severely damaged and well-preserved areas. For these regions, a balanced management approach that integrated both conservation and sustainable use in recommended to ensure ecological resilience.

Estimation of Road-Network Performance and Resilience According to the Strength of a Disaster (재난 강도에 따른 도로 네트워크의 성능 및 회복력 산정 방안)

  • Jung, Hoyong;Choi, Seunghyun;Do, Myungsik
    • International Journal of Highway Engineering
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    • v.20 no.1
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    • pp.35-45
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    • 2018
  • PURPOSES : This study examines the performance changes of road networks according to the strength of a disaster, and proposes a method for estimating the quantitative resilience according to the road-network performance changes and damage scale. This study also selected high-influence road sections, according to disasters targeting the road network, and aimed to analyze their hazard resilience from the network aspect through a scenario analysis of the damage recovery after a disaster occurred. METHODS : The analysis was conducted targeting Sejong City in South Korea. The disaster situation was set up using the TransCAD and VISSIM traffic-simulation software. First, the study analyzed how road-network damage changed the user's travel pattern and travel time, and how it affected the complete network. Secondly, the functional aspects of the road networks were analyzed using quantitative resilience. Finally, based on the road-network performance change and resilience, priority-management road sections were selected. RESULTS : According to the analysis results, when a road section has relatively low connectivity and low traffic, its effect on the complete network is insignificant. Moreover, certain road sections with relatively high importance can suffer a performance loss from major damage, for e.g., sections where bridges, tunnels, or underground roads are located, roads where no bypasses exist or they exist far from the concerned road, including entrances and exits to suburban areas. Relatively important roads have the potential to significantly degrade the network performance when a disaster occurs. Because of the high risk of delays or isolation, they may lead to secondary damage. Thus, it is necessary to manage the roads to maintain their performance. CONCLUSIONS : As a baseline study to establish measures for traffic prevention, this study considered the performance of a road network, selected high-influence road sections within the road network, and analyzed the quantitative resilience of the road network according to scenarios. The road users' passage-pattern changes were analyzed through simulation analysis using the User Equilibrium model. Based on the analysis results, the resilience in each scenario was examined and compared. Sections where a road's performance loss had a significant influence on the network were targeted. The study results were judged to become basic research data for establishing response plans to restore the original functions and performance of the destroyed and damage road networks, and for selecting maintenance priorities.

Integrated urban resilience framework: A comprehensive approach to pre- and post-disaster assessment for earthquake risk reduction

  • Ayse E. Ozsoy Ozbay;Isil Sanri Karapinar;Huseyin C. Unen
    • Structural Engineering and Mechanics
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    • v.92 no.2
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    • pp.197-206
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    • 2024
  • In this study, a unified framework that integrates pre- and post-earthquake assessments of buildings was proposed to enhance urban disaster preparedness through the coordination of pre- and post- earthquake efforts. Within this framework, a case study based on the 2023 Kahramanmaraş Earthquake was performed comparing the distribution of seismic risk prioritization for 117 reinforced concrete buildings with their actual damage states observed during post-earthquake field inspections. In order to conduct pre-earthquake evaluation process, street-level images were employed using two different rapid visual screening methods. With the use of generated geospatial database enabling the efficient and reliable transmission of the data between both stages of the assessment procedures, the alignment and validation of pre- and post-earthquake evaluations of the buildings were achieved enhancing the coordination of seismic risk management strategies. By implementing the proposed joint framework in this study, an extensive seismic vulnerability evaluation on an urban scale could be achieved by optimizing the computational demands, cost and time required for the strategic planning activities.

Slum Areas in Battambang and Climate Resilience

  • Samnang, Rem;Chanthol, Hay
    • Asian Journal for Public Opinion Research
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    • v.5 no.2
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    • pp.104-126
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    • 2018
  • As the second most populous province in Cambodia, Battambang also exhibits an increasing number of urban poor areas. This research focuses on the economic situation of slum areas in Battambang and how people in slum areas are affected by climate change. This research report describes socioeconomics of people living in slum areas in 4 villages in Battambang City. An investigation will be made on motivation of moving to slum areas, access to water, access to sanitation, access to electricity, transport and delivery, access to health care, access to education, security of tenure, cost of living in slum, literacy, and access to finance. We also explore the policy of the public sector toward climate change in Cambodia.

A Spatial Projection of Demand for Green Infrastructure and Its Application to GeoDesign - Evidence-Based Design for Urban Resilience - (융합도시모델링을 통한 그린인프라 수요 예측 및 지오디자인 적용 - 도시 레질리언스를 위한 근거 기반 디자인 -)

  • Kwak, Yoonshin
    • Journal of the Korean Institute of Landscape Architecture
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    • v.51 no.5
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    • pp.30-43
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    • 2023
  • Green infrastructure(GI) is considered a key strategy in establishing sustainable communities. However, research on GI from the perspective of urban system dynamics and resilience lacks depth, as does its integration with physical design. This research addresses two primary causes. First, there is a gap in methods between existing GI planning, which considers static variables, and urban modeling research, which addresses dynamic variables. Second, there is a gap in information between landscape design and urban modeling research. To address these issues, this study proposes an integrated modeling approach in consideration of design decision-making. By combining the LEAM model and MCDA model, this study evaluates the relationship between GI services and socioeconomic growth, while spatially forecasting the geographies of GI demand in 2050. The resulting information reveals a potential degradation in ecosystem services over the region due to Chicago's sub-urbanization. This indicates that there would be a spatial shift in GI demand, emphasizing the need for comprehensive, dynamic GI strategies. This study further discusses the applications of evidence-based design in a studio environment. This study aims to contribute to the GeoDesign literature in terms of the creation of a more resilient urban environment by facilitating efficient evidence-based decision-making.

Performance Assessment of Three Turfgrass Species, in Three Different Soil Types, and their Responses to Water Deficit in Reinforced Cells, Growing in the Urban Environment

  • Ow, L.F;Ghosh, S.;Chin, S.W.
    • Weed & Turfgrass Science
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    • v.4 no.4
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    • pp.338-347
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    • 2015
  • Reinforcement cells are used to aid grass growth and taken together, this serves to extend greenery beyond the conventional spaces of lawns, tree pits, gardens, and parks, and is advantageous to urban cities since space for greening is often limited. Drought has variable effects on plant life and the resilience of turf to drought resistance also varies with species. Changes in photosynthetic ability were more pronounced for media rather than grass species. The media of sand without organic matter was found to be least suited for drought resistance. Normalized difference vegetation index (NDVI) and digital image analysis (DIA) data were generally in favour of Zoysia species as oppose to A. compressus. In A. compressus, selective traits such as, a more extensive root system and lower specific leaf area (SLA) were not an underlying factor that assisted this grass with enhanced drought resistance. Generally, WUE was found to be strongly related to plant characterises such as overall biomass, photosynthetic features as well as the lushness indexes, and specific leaf area. This study found a strong relationship between WUE and a suite of plant characteristics. These traits should serve as useful selection criteria for species with the ability to resist water stress.