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Measures of product design adaptability for changing requirements
- Serdar Uckun, Ryan Mackey, Minh Do, Rong Zhou, Eric Huang, Jami J. Shah
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Adaptability can have many different definitions: reliability, robustness, survivability, and changeability (adaptability to requirements change). In this research, we focused entirely on the last type. We discuss two alternative approaches to requirements change adaptability. One is the valuation approach that is based on utility and cost of design changes in response to modified requirements. The valuation approach is theoretically sound because it is based on utility and decision theory, but it may be difficult to use in the real world. The second approach is based on examining product architecture characteristics that facilitate changes that include modularity, hierarchy, interfaces, performance sensitivity, and design margins. This approach is heuristic in nature but more practical to use. If calibrated, it could serve as a surrogate for real adaptability. These measures were incorporated in a software tool for exploring alternative configurations of fractionated space satellite systems.
Effect of fertility on the economics of pasture-based dairy systems
- L. Shalloo, A. Cromie, N. McHugh
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There are significant costs associated with reproductive inefficiency in pasture-based dairy herds. This study has quantified the economic effect of a number of key variables associated with reproductive inefficiency in a dairy herd and related them to 6-week calving rate for both cows and heifers. These variables include: increased culling costs, the effects of sub optimum calving dates, increased labour costs and increased artificial insemination (AI) and intervention costs. The Moorepark Dairy Systems Model which is a stochastic budgetary simulation model was used to simulate the overall economic effect at farm level. The effect of change in each of the components was simulated in the model and the costs associated with each component was quantified. An analysis of national data across a 4-year period using the Irish Cattle Breeding Federation database was used to quantify the relationship between the 6-week calving rate of a herd with survivability (%), calving interval (days) and the level of AI usage. The costs associated with increased culling (%), calving date slippage (day), increased AI and intervention costs (0.1 additional inseminations), as well as, increased labour costs (10%) were quantified as €13.68, €3.86, €4.56 and €29.6/cow per year. There was a statistically significant association between the 6-week calving rate and survivability, calving interval and AI usage at farm level. A 1% change in 6-week calving rate was associated with €9.26/cow per annum for cows and €3.51/heifer per annum for heifers. This study does not include the indirect costs such as reduced potential for expansion, increased costs associated with failing to maintain a closed herd as well as the unrealised potential within the herd.
Surviving Collapsed Structure Entrapment after Earthquakes: A “Time-to-Rescue” Analysis
- Anthony G. Macintyre, Joseph A. Barbera, Edward R. Smith
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- Journal:
- Prehospital and Disaster Medicine / Volume 21 / Issue 1 / February 2006
- Published online by Cambridge University Press:
- 28 June 2012, pp. 4-17
- Print publication:
- February 2006
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Introduction:
Massive earthquakes often cause structures to collapse, trapping victims under dense rubble for long periods of time. Commonly, this spurs resource intensive, dangerous, and frustrating attempts to find and extricate live victims. The search and rescue phase usually is maintained for many days beyond the last “save,” potentially diverting critical attention and resources away from the pressing needs of non-trapped survivors and the devastated community. This recurring phenomenon is driven by the often-unanswered question “Can anyone still be alive under there?” The maximum survival time in entrapment is an important issue for responders, yet little formal research has been conducted on this issue. Knowing the maximum survival time in entrapment helps responders: (1) decide whether or not they should continue to assign limited resources to search and rescue activities; (2) assess the safety risks versus the benefits; (3) determine when search and rescue activities no longer are indicated; and (4) time and pace the important transition to community recovery efforts.
Methods:The time period of 1985–2004 was selected for investigation. Medline and Lexis-Nexis databases were searched for earthquake events that occurred within this timeframe. Medical literature articles providing time-torescue data for victims of earthquakes were identified. Lexis-Nexis reports were scanned to select those with time-to-rescue data for victims of earthquakes. Reports from both databases were examined for information that might contribute to prolonged survival of entrapped individuals.
Results:A total of 34 different earthquake events met study criteria. Fortyeight medical articles containing time-to-rescue data were identified. Of these, the longest time to rescue was “13–19 days” post-event (secondhand data and the author is not specific). The second longest time to rescue in the medical articles was 8.7 days (209 hours). Twenty-five medical articles report multiple rescues that occurred after two days (48 hours). Media reports describe rescues occurring beyond Day 2 in 18 of 34 earthquakes. Of these, the longest reliably reported survival is 14 days after impact, with the next closest having survived 13 days. The average maximum times reported from these 18 earthquakes was 6.8 days (median = 5.75 days). The event with the most media reports of distinct rescue events was the 1999 Marmara, Turkey earthquake (43 victims). Times range from 0.5 days (12 hours) to 6.2 days (146 hours) for this event. Both databases provide little formal data to develop detailed insight into factors affecting survivability during entrapment.
Conclusions:A thorough search of the English-language medical literature and media accounts provides a provocative picture of numerous survivors beyond 48 hours of entrapment under rubble, with a few successfully enduring entrapment of 13–14 days. These data are not necessarily applicable to non-earthquake collapsed-structure events. For incident managers and their medical advisors, the study findings and discussion may be useful for postimpact decision-making and in establishing and/or revising incident priorities as the response evolves.
Disaster Triage: START, then SAVE—A New Method of Dynamic Triage for Victims of a Catastrophic Earthquake
- Mark Benson, Kristi L. Koenig, Carl H. Schultz
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- Journal:
- Prehospital and Disaster Medicine / Volume 11 / Issue 2 / June 1996
- Published online by Cambridge University Press:
- 28 June 2012, pp. 117-124
- Print publication:
- June 1996
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Triage of mass casualties in situations in which patients must remain on-scene for prolonged periods of lime, such as after a catastrophic earthquake, differs from traditional triage. Often there are multiple scenes (sectors), and the infrastructure is damaged. Available medical resources are limited, and the time to definitive care is uncertain. Early evacuation is not possible, and local initial responders cannot expect significant outside assistance for at least 49–72 hours. Current triage systems are based either on a shorter time to definitive care or on a longer time to initial triage.
The Medical Disaster Response (MDR) project deals with the scenario in which specially trained, local health-care providers evaluate patients immediately after the event, but cannot evacuate patients to definitive care. For this type of scenario, a dynamic triage methodology was developed that permits the triage process to evolve over hours or even days, thereby maximizing patient survival and resulting in a more efficient use of resources. This MDR system incorporates a modified version of “Simple Triage and Rapid Treatment” (START) that substitutes radial pulse for capillary refill, coupled with a system of secondary triage termed, “Secondary Assessment of Victim Endpoint” (SAVE).
The SAVE triage was developed to direct limited resources to the subgroup of patients expected to benefit most from their use. The SAVE assesses survivability of patients with various injuries and, on the basis of trauma statistics, uses this information to describe the relationship between expected benefits and resources consumed. Because early transport to an intact medical system is unavailable, this information guides treatment priorities in the field to a level beyond the scope of the START methodology.
Pre-existing disease and age are factored into the triage decisions. An elderly patient with burns to 70% of body surface area is unsalvageable under austere field conditions and would require the use of significant medical resources—both personnel and equipment—and would be triaged to an “expectant area.” Conversely, a young adult with a Glasgow Coma Scale score of 12 who requires only airway maintenance would use few resources and would have a reasonable chance for survival with the interventions available in the field, and would be triaged to a “treatment” area.
The START and SAVE triage techniques are used in situations in which triage is dynamic, occurs over many hours to days, and only limited, austere, field, advanced life support equipment is readily available. The MDR-SAVE methodology is the first systematic attempt to use triage as a tool to maximize patient benefit in the immediate aftermath of a catastrophic disaster.