Service restoration

The phases and their proportions present ia hardened amalgam are controlled by many factors. The composition of the alloy the size, shape, and size distribution of the particles the thermal history of the cast ingot and the comminuted alloy and the surface treatment of the particles are some of the factors for which the manufacturer is responsible. The tooth cavity preparation and the mixing, compacting, and finishing techniques of the dentist can make the difference between satisfactory and unsatisfactory restorations, even with the best of alloys. A minimal amount of residual mercury and porosity are needed to obtain the most serviceable restorations (138). 

Define service restoration instructions covering the actions required to restore equipment or facilities into service, including restoration and response times. This is usually first line maintenance and may not require any repair action. 

The phone company used a priority scheme to restore telephone service to critical customers first. Many residents waited over two weeks to have their service restored. ... 

For SONET/ATM networks, network restoration can be performed at the physical (SONET) or ATM layer. For physical layer protection, service restoration can be performed at the STS-3Nc level (where N = I, 4, or 16) or at the physical transmission Hnk level. For ATM layer protection, network restoration can be performed at the VC or VP (or group of VPs) level. Service restoration at the VC level is typically slower and more expensive than that performed at the VP level due to greater VC-based ATM network complexity. The restoration system complexity at the VP level is similar to that at the STS-1 /STS-3c level. Determining which layer (SONET, VP, or VC) is an appropriate restoration layer depends on the SONET/ATM network architecture and other factors such as costs and QoS. 

Short-term recovery a process of recovery that is immediate and overlaps emergency response actions includes such actions as providing essential public health and safety services, restoring interrupted utility and other essential services, reestablishing transportation routes, and providing food and shelter for those displaced by a disaster (although called short term, some of these activities may last for weeks)... 

Infrastructure service categories Lifeline system earthquake resilience Performance objectives Post-earthquake service restoration... 

The ability of systems to provide the service categories in Tables 2, 3, and 4 can be assessed at any given time as a ratio of the number of customers with the service after an earthquake to the number of customers having the service before the earthquake. An assessment can be performed in relation to a hazard evaluation or an actual event for each service category in Tables 2, 3, or 4. As exemplified in Fig. la-c, the number of customer services restored over time can be monitored to track and evaluate overall system serviceability for each category. 

The service restoration curves in Fig. la-c do not represent the performance of any specific system following any specific earthquake... 

Example water service restoration curves, (b) Example wastewater service restoration curves, (c) Example inundation protection service restoration curves... 

Resiliency of Water, Wastewater, and Inundation Protection Systems, Fig. 3 Example service restorations showing bounding operability curves (a) water services (b) wastewater services (c) inundation protection services... 

As previously described, operability is achieved through a combination of service restorations, but caimot by itself be described as a service. The time it takes to obtain operability status throughout a system can only be viewed as the temporal sum to incrementally restore all the services other than functionality (e.g., wastewater collection, quality, disposal, and reclaimed source for wastewater systems) and therefore serves as a descriptive milestone delineating when customers resume receipt of their accustomed services. Thus, it is important to understand how to assess each service category and its respective characteristics. 

The service restoration calculation methodology is as follows (1) identify the area (s) where services are not being met, (2) count the number of services (or people, businesses, etc.) in each area, and (3) calculate the ratio for number of post-earthquake services to pre-earthquake services for each category in Tables 2, 3, and 4. The water, wastewater, and inundation protection service restoration curves are plots of this quantification over time. For post-event restoration estimates, the calculation for all services except functionality is relatively independent of system layout and operations, whereas an assessment for an earthquake scenario may require an understanding of system layout and some hydraulic analysis. Functionality services, however, cannot be estimated in any case without a full understanding of systemic capabilities. For this reason the remainder of this section describes quantification of postearthquake functionality. 

Angeles watCT system service restorations following the 1994 Northridge earthquake... 

The Los Angeles water system has a high level of supply and transmission redundancy which was utilized to provide continued services through the non-damaged portions of the system. Figure 6 shows the entire functionality service restoration, which is calculated using the... 

Descriptions of normally provided water, waste-water, and inundation protection service performance categories have been presented in relation to their importance to post-earthquake system restorations. A clear distinction is made herein between functionality service restoration and system operability (restoration of the other service categories for each system) and their respective relations to (a) water, wastewater, and inundation protection system resilience and (b) community resilience. Methodologies useful for estimating and tracing the service restorations over time have been presented. A case study on service restorations for the Los Angeles... 

Water System applied these methodologies and showed how the service categories are applicable to actual systems that experience earthquake damage. The relationship between water, wastewater, and inundation protection system service restorations and seismic resilience was illustrated system resilience cannot be fully described independent of community resilience. 

Davis CA, O Rourke TD, Adams ML, Rho MA (2012) Case study Los Angeles water services restoration following the 1994 Northridge Earthquake. In 15th world conference on earthquake engineering, Lisbon, 24-28 Sept 2012, paper no 0364... 

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