A Consistency Model for Identity Information in Distributed Systems

2010 ◽  
Author(s):  
Thorsten Hoellrigl ◽  
Jochen Dinger ◽  
Hannes Hartenstein
Keyword(s):  
Distributed Systems ◽  
Identity Information ◽  
Consistency Model

scholarly journals Checking Robustness Between Weak Transactional Consistency Models

2021 ◽  
pp. 87-117
Author(s):  
Sidi Mohamed Beillahi ◽  
Ahmed Bouajjani ◽  
Constantin Enea
Keyword(s):  
Distributed Systems ◽  
Polynomial Time ◽  
Reduction Theory ◽  
Proof Technique ◽  
Reachability Problem ◽  
Snapshot Isolation ◽  
Trade Offs ◽  
Consistency Model ◽  
Causal Consistency ◽  
Consistency Models

AbstractConcurrent accesses to databases are typically encapsulated in transactions in order to enable isolation from other concurrent computations and resilience to failures. Modern databases provide transactions with various semantics corresponding to different trade-offs between consistency and availability. Since a weaker consistency model provides better performance, an important issue is investigating the weakest level of consistency needed by a given program (to satisfy its specification). As a way of dealing with this issue, we investigate the problem of checking whether a given program has the same set of behaviors when replacing a consistency model with a weaker one. This property known as robustness generally implies that any specification of the program is preserved when weakening the consistency. We focus on the robustness problem for consistency models which are weaker than standard serializability, namely, causal consistency, prefix consistency, and snapshot isolation. We show that checking robustness between these models is polynomial time reducible to a state reachability problem under serializability. We use this reduction to also derive a pragmatic proof technique based on Lipton’s reduction theory that allows to prove programs robust. We have applied our techniques to several challenging applications drawn from the literature of distributed systems and databases.

A Longitudinal Study of Mental Health in Emerging Adults

2014 ◽  
Vol 73 (3) ◽  
pp. 135-141 ◽  
Author(s):  
Monica S. Bachmann ◽  
Hansjörg Znoj ◽  
Katja Haemmerli
Keyword(s):  
Mental Health ◽  
Longitudinal Study ◽  
Emerging Adults ◽  
Poor Mental Health ◽  
Need Satisfaction ◽  
Computer Assisted ◽  
Consistency Model ◽  
Negative Effect ◽  
The Cross ◽  
Health Model

Emerging adulthood is a time of instability. This longitudinal study investigated the relationship between mental health and need satisfaction among emerging adults over a period of five years and focused on gender-specific differences. Two possible causal models were examined: (1) the mental health model, which predicts that incongruence is due to the presence of impaired mental health at an earlier point in time; (2) the consistency model, which predicts that impaired mental health is due to a higher level of incongruence reported at an earlier point in time. Emerging adults (N = 1,017) aged 18–24 completed computer-assisted telephone interviews in 2003 (T1), 2005 (T2), and 2008 (T3). The results indicate that better mental health at T1 predicts a lower level of incongruence two years later (T2), when prior level of incongruence is controlled for. The same cross-lagged effect is shown for T3. However, the cross-lagged paths from incongruence to mental health are marginally associated when prior mental health is controlled for. No gender differences were found in the cross-lagged model. The results support the mental health model and show that incongruence does not have a long-lasting negative effect on mental health. The results highlight the importance of identifying emerging adults with poor mental health early to provide support regarding need satisfaction.

Managing evolution in distributed systems

1989 ◽  
Vol 4 (6) ◽  
pp. 321 ◽  
Author(s):  
Jeff Kramer ◽  
Jeff Magee ◽  
Morris Sloman
Keyword(s):  
Distributed Systems
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