Flexible Design of Systems Considering Time-Dependent Reliability

2015 ◽  
Author(s):  
Vijitashwa Pandey ◽  
Zissimos P. Mourelatos ◽  
Annette Skowronska
Keyword(s):  
Time Dependent ◽  
Time Varying ◽  
Repairable Systems ◽  
Flexible Design ◽  
Change Over Time ◽  
New Approach ◽  
Hydrokinetic Turbine ◽  
The Future ◽  
Over Time

Many repairable systems degrade with time and are subjected to time-varying loads. Their characteristics may change over time considerably, making the assessment of their performance and hence their design difficult. To address this issue, we introduce in this paper the concept of flexible design of repairable systems under time-dependent reliability considerations. In flexible design, the system can be modified in the future to accommodate uncertain events. As a result, regardless of how uncertainty resolves itself, a modification is available that will keep the system close to optimal provided failure events have been properly characterized. We discuss how flexible design of repairable systems requires a fundamentally new approach and demonstrate its advantages using the design of a hydrokinetic turbine. Our results show that long-term metrics are improved when time-dependent characteristics and flexibility are considered together.

Is Humanity Destined to Self-Destruct?

1999 ◽  
Vol 18 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Lynton Keith Caldwell
Keyword(s):  
Twentieth Century ◽  
Human Life ◽  
Cooperative Effort ◽  
Term Survival ◽  
Change Over Time ◽  
Long Term Survival ◽  
Sustainable Future ◽  
The Future ◽  
Over Time

As the twentieth century ends, we may identify both constructive and destructive trends that will influence the future of humanity. Which set of trends will dominate the future is uncertain. Attitudes, beliefs, and behaviors all interact to direct the flow of change over time. However, the options and constraints of human life are ultimately fixed by those cosmic elements of the environment over which humans have no control. The modern assumption of a world without end or limits risks collision with that obdurate reality. Facing threats to its long-term survival, humanity is challenged to learn how to build a sustainable future. A successful effort will require a concerted and cooperative effort among all fields of knowledge. This article identifies some of the trends that threaten humanity's future and suggests four lines of action that should be pursued in order to reduce the likelihood that humanity will destroy itself.

scholarly journals Agritourism—A Business Reality of the Moment for Romanian Rural Area’s Sustainability

2021 ◽  
Vol 13 (11) ◽  
pp. 6313
Author(s):  
Ramona Ciolac ◽  
Tiberiu Iancu ◽  
Ioan Brad ◽  
Tabita Adamov ◽  
Nicoleta Mateoc-Sîrb
Keyword(s):  
Rural Communities ◽  
Distribution Channels ◽  
Scientific Paper ◽  
Business Owners ◽  
The Future ◽  
Tourism Potential ◽  
The Moment ◽  
Managerial Experience ◽  
Over Time

The agritourism activity can be a characteristic reality of the present, considering rural area’s sustainability, being at the same time a business reality for rural entrepreneurs and a “must have” for rural communities that have tourism potential. It is a form of tourism, through which the tourist can receive a qualitative product at a reasonable price, but also a field that can ensure sustainable development over time, being at the same time environmentally friendly. The purpose of this scientific paper is to identify the aspects that make agritourism “a possible business reality of the moment”, for Romanian rural area’s sustainability. We take into account the following areas: Bran-Moieciu area—considered “the oldest” in terms of agritourism experience, and Apuseni Mountains area, with a great inclination and potential for this activity. The study conducted for these two areas is focused on several aspects: the degree of involvement in agritourism activities, considering the number of years and managerial experience, the analysis of the types of activities/experiences offered by agritourism structures, the identification of the main reasons/motivations for the orientation towards agritourism and the manner in which this field is perceived. Aspects related to the marketing-finance part of the agritourism business are also taken into account: customers, distribution channels, financial sources, shortcomings observed by agritourism business owners and possible action directions so as to improve the activity/agritourism product. Agritourism may be “a possible business reality of the moment” for the studied areas and not only, but in the future, the entrepreneur/farmer must be constantly updated because of the changing situations that appear on the market, be able to make sustainable decisions for his/her own business, which in the future will ensure its viability and obviously its long-term profitability and development, and in the same time rural area’s sustainability.

Gender, mobility and contact

2021 ◽  
Vol 7 (2) ◽  
pp. 142-167
Author(s):  
Catherine E. Travis ◽  
Inas Ghina
Keyword(s):  
Older Women ◽  
High Mobility ◽  
Spontaneous Speech ◽  
Social Changes ◽  
Change Over Time ◽  
Aceh Province ◽  
Rural Variety ◽  
The Impact ◽  
Over Time

Abstract We examine variation in a rural variety of Acehnese spoken in Aceh Province, to better understand the impact of long-term contact with Indonesian and increasing urbanization. The Great Aceh variety is characterized by variable realization of word-final (t) as a dental vs. glottal stop. Analyses of over 2,000 tokens of this variable from a corpus of spontaneous speech from 35 speakers indicate that the variability is relatively stable among men, and among women of high mobility, measured in terms of education, occupation, and time spent outside Great Aceh. Women with low mobility produce the lowest rates of [t̪], and in this group we observe a higher rate of [t̪] by younger than older women, suggesting change over time. We thus find both stability – among those who have long enjoyed high levels of mobility – and change – among those most affected by recent social changes, namely low-mobility women.

The Historyless Heathen and the Stagnating Pagan: History as Non-Native Category?

2018 ◽  
Vol 28 (1) ◽  
pp. 52-91 ◽  
Author(s):  
Kathryn Gin Lum
Keyword(s):  
Nineteenth Century ◽  
Core Component ◽  
Change Over Time ◽  
The Past ◽  
The Future ◽  
Religious Perspectives ◽  
Over Time

AbstractThis article asks whether and how J. Z. Smith's contention that religion is a “non-native category” might be applied to the discipline of history. It looks at how nineteenth-century Americans constructed their own understandings of “proper history”—authenticatable, didactic, and progressive—against the supposed historylessness of “heathen” Hawaiians and stagnation of “pagan” Chinese. “True” history, for these nineteenth-century historians, changed in the past and pointed to change in the future. The article asks historians to think about how they might be replicating some of the same assumptions about forward-moving history by focusing on change over time as a core component of historical narration. It urges historians to instead also incorporate the native historical imaginations of our subjects into our own methods, paying attention to when those imaginations are cyclical and reiterative as well as directional, and letting our subjects' assumptions about time and history, often shaped by religious perspectives, orient our own decisions about how to structure the stories we tell.

scholarly journals A Tutorial on Evaluating the Time-Varying Discrimination Accuracy of Survival Models Used in Dynamic Decision Making

2018 ◽  
Vol 38 (8) ◽  
pp. 904-916 ◽  
Author(s):  
Aasthaa Bansal ◽  
Patrick J. Heagerty
Keyword(s):  
Decision Making ◽  
Statistical Methods ◽  
Sensitivity And Specificity ◽  
Prognostic Model ◽  
Dynamic Decision Making ◽  
Time Dependent ◽  
Survival Models ◽  
Biliary Cirrhosis ◽  
Time Varying ◽  
Over Time

Many medical decisions involve the use of dynamic information collected on individual patients toward predicting likely transitions in their future health status. If accurate predictions are developed, then a prognostic model can identify patients at greatest risk for future adverse events and may be used clinically to define populations appropriate for targeted intervention. In practice, a prognostic model is often used to guide decisions at multiple time points over the course of disease, and classification performance (i.e., sensitivity and specificity) for distinguishing high-risk v. low-risk individuals may vary over time as an individual’s disease status and prognostic information change. In this tutorial, we detail contemporary statistical methods that can characterize the time-varying accuracy of prognostic survival models when used for dynamic decision making. Although statistical methods for evaluating prognostic models with simple binary outcomes are well established, methods appropriate for survival outcomes are less well known and require time-dependent extensions of sensitivity and specificity to fully characterize longitudinal biomarkers or models. The methods we review are particularly important in that they allow for appropriate handling of censored outcomes commonly encountered with event time data. We highlight the importance of determining whether clinical interest is in predicting cumulative (or prevalent) cases over a fixed future time interval v. predicting incident cases over a range of follow-up times and whether patient information is static or updated over time. We discuss implementation of time-dependent receiver operating characteristic approaches using relevant R statistical software packages. The statistical summaries are illustrated using a liver prognostic model to guide transplantation in primary biliary cirrhosis.

scholarly journals EAR BIOMETRICS: ONE MORE STEP TOWARDS SOCIAL DISTANCING

2021 ◽  
Vol 5 (9) ◽  
Author(s):  
Mansi Talreja ◽  
Bhavika Motiramani ◽  
Muskan Asrani ◽  
Ashish Sukhani ◽  
Manas Mangaonkar
Keyword(s):  
Change Over Time ◽  
Social Distancing ◽  
Ear Biometrics ◽  
The Future ◽  
Secure Environment ◽  
Over Time

Biometrics deals with identification of individuals based on their characteristics. In traditional systems people use to remember passwords, PIN's, tokens for identification. But in recent years biometrics have gained a lot of popularity due to advancement in technology and the secure environment. Variety of biometrics have been developed in recent years such as fingerprint, iris, retinal. Ears are considered as the future of biometrics due to its properties of Universality, which means that every person should have it. Uniqueness, which indicates that no two persons should behave the same characteristic. Permanence, which means that this characteristic does not change over time. Collectability, which indicates that the characteristic can be measured quantitatively. Ears are comparatively large in size and hence are more visible and also their shape does not change radically over a period of time and so are their images easy to be captured.

Raptor Prey Remains

2020 ◽  
Author(s):  
Ed Drewitt
Keyword(s):  
Feeding Ecology ◽  
Prey Species ◽  
Local Level ◽  
Body Parts ◽  
Change Over Time ◽  
The Common ◽  
Prey Remains ◽  
Over Time ◽  
Prey Populations

Are you curious about the remains of an animal you have found? This compilation of the most likely found body parts of animals eaten by raptors will help you identify your discovery. Including over 100 species of bird and mammal prey of raptors such as sparrowhawks, peregrines and hen harriers, this photographic guide highlights the common feathers, fur and other body parts found at raptor nests, roosts, plucking posts and other opportunistic spots. Discovering what raptors eat is an important part of confirming their feeding ecology and how this might change over time, vary on a local level or in response to changing prey populations, as well as dispelling myths and assumptions about what certain raptor species eat. Diet studies are vital for the conservation of raptor species; the more we know about what they need for survival the more we can predict and plan long-term for the protection and survival of raptors that may be vulnerable and in decline. This is the first book to show in detail the actual parts of a bird, mammal or other animal that you are likely to find in a garden, woodland or beneath a raptor roost. As more people take an interest in raptors and watch species such as peregrines via webcams and through watch groups, there is greater opportunity for finding prey remains. This book provides the first and most important step in identifying a prey species.

Percutaneous Endoscopic Transgastric Jejunostomy: A New Approach

2005 ◽  
Vol 71 (3) ◽  
pp. 216-218 ◽  
Author(s):  
Willie Melvin ◽  
Joss D. Fernandez
Keyword(s):  
Gastric Emptying ◽  
Feeding Tube ◽  
Seldinger Technique ◽  
New Approach ◽  
The Future ◽  
Gastric Decompression ◽  
Entire Procedure ◽  
Future Management

A percutaneous transgastric jejunostomy allows long-term simultaneous gastric decompression and jejunal feedings. We have developed a safe and effective bedside technique for placement of a large-bore (22 French) feeding tube while providing gastric drainage with no mortalities and minimal morbidities. We have modified the push technique used for percutaneous gastrostomies and introduced a cut-away sheath that is placed using a modified Seldinger technique. The entire procedure is performed under endoscopic visualization. Our experience with more than 100 successful tube placements has made this method common practice at our institute. This technique is ideal for patients with poor gastric emptying of any etiology. We feel that this technique will have an expanding and important role in the future management of this patient population's nutritional problems.

Sign in / Sign up

Export Citation Format

Share Document