How to make better consistency and availability trade-offs in networks
New theorem benefits distributed system design
2023-04-06
(Press-News.org)
Imagine you want to withdraw some cash from an ATM. You expect it to show your account balance correctly and process your request quickly. However, network delays make it hard for the system to meet both of these simple expectations at the same time. If an ATM system tries to achieve high “consistency,” meaning that it displays the latest account balance by checking a remote database, it could make you wait or even prevent you from accessing your accounts during busy times. On the other hand, if an ATM system favors “availability,” it could let you access your accounts fast, but risk showing inaccurate information. To avoid undesired results, designing ATM systems and other distributed systems requires making smart trade-offs.
Seeking to help system designers make those trade-offs, a group of researchers from the University of California, Berkeley and the Technical University of Dresden discovered a simple algebraic relationship between consistency, availability and network latency. This research was published Feb.15 in Intelligent Computing, a Science Partner Journal.
The researchers call this algebraic relationship the consistency-availability-apparent latency theorem; it quantifies consistency, availability and apparent latency as time intervals. The CAL theorem builds on Eric Brewer’s well-known consistency-availability-network partitioning theorem. Unlike the CAP theorem, which makes system designers choose upfront to sacrifice consistency, availability or both when a network lapse occurs, the CAL theorem allows system designers to adjust their choices depending on the situation — a method that enables “rigorous design with clearly stated assumptions.”
Rigorous design is essential for distributed systems that control complex networks of connected devices such as factory robots, medical devices and security systems, which have varying latencies at different nodes and are prone to network failures. Using the CAL theorem and Lingua Franca coordination language, a powerful tool that lets programmers specify how different nodes should interact with each other, system designers can model complex networks and use the results to customize distributed systems for reliability and efficiency.
The researchers demonstrated the effectiveness of their approach using a simple ATM network for tracking balances and processing transactions. They used the CAL theorem to model a network of ATMs and derive bounds on the network’s latency based on minimum consistency and availability requirements specified using the LF coordination language. Keeping within these bounds, they were able to optimize the design of the network by making decisions about software placement and trade-offs between consistency and availability. In the real world, such optimization may be necessary for the achievement of business goals.
The researchers also showed how to detect and handle violations of network latency requirements after deploying such a system. With built-in fault handlers provided by the LF coordination language, system designers can choose to sacrifice consistency or availability and “handle such failures gracefully.”
Additionally, the researchers implemented two coordination extensions based on the CAL theorem — one centralized and one decentralized — that support flexible trade-offs between consistency and availability as network latency changes. The centralized coordination mechanism prioritizes consistency, while the decentralized one prioritizes availability. A system employing these mechanisms can be customized according to the needs of the context.
END
ELSE PRESS RELEASES FROM THIS DATE:
2023-04-06
The Science family journals have announced a partnership with the nonprofit data repository Dryad that simplifies the process by which authors deposit data underlying new work – a critical step to facilitating data’s routine reuse. The partnership is yet another step taken by the Science journals to ensure data the scientific community requires to verify, replicate and reanalyze new research is openly available.
“Addressing public access to data at scale is a critical challenge,” said Holden Thorp, Editor-in-Chief of the Science family ...
2023-04-06
A new study from UCLA researchers finds sex-specific brain signals that appear to confirm that different drivers lead men and women to develop obesity. The study, appearing in the peer-reviewed journal Brain Communications, combined data from several modes of MRI with patients’ clinical features and personal histories to identify sex-specific mechanisms in the brain underlying obesity.
“We found differences in several of the brain’s networks associated with early life adversity, mental ...
2023-04-06
Some adults with severe respiratory illness, including women, those with public insurance, and people with fewer financial resources, may be less likely to receive an advanced form of life support known as extracorporeal membrane oxygenation (ECMO). A research team supported by the National Institutes of Health found that adults who received ECMO appeared to skew toward men, people with private health insurance, and those who came from areas with higher median incomes. ECMO helps patients with life-threatening illness or injury breathe by simulating the function of the heart and/or lungs, while giving those organs a chance to rest.
The study published in the Annals of the American ...
2023-04-06
The number of immune cells in and around kidney tumors, the amount of dead cancer tissue, and mutations to a tumor suppressor gene called PBRM1 form a biomarker signature that can predict — before treatment begins — how well patients with kidney cancer will respond to immunotherapy, according to new research directed by investigators at the Johns Hopkins Kimmel Cancer Center and its Bloomberg~Kimmel Institute for Cancer Immunotherapy.
In reviews of 136 kidney tumor biopsies taken for previous studies, investigators found that patients who had three positive factors — presence of immune cells in and around tumors, known as tumor-infiltrating immune cells, absence ...
2023-04-06
Studies of consciousness often run into a common conundrum of science—it’s hard to measure a system without the measurement affecting the system. Researchers assessing consciousness, for instance as volunteers receive anesthesia, typically use spoken commands to see if subjects can still respond, but that sound might keep them awake longer or wake them up sooner than normal. A new study not only validates a way to assess consciousness without external stimulation, it also finds that it may be more precise.
“We want to measure when people make the transition from conscious to unconscious, and vice versa, but as soon as you ask someone to do something, which is the classic ...
2023-04-06
A chemical analyst and expert in micro-extraction at The University of Toledo created a more reliable, robust and efficient way to monitor pesticide exposure and help protect the health and safety of agricultural workers, especially for emerging sectors like the cannabis industry.
Dr. Emanuela Gionfriddo, an assistant professor of analytical chemistry, and Nipunika H. Godage, a Ph.D. candidate in UToledo’s Dr. Nina McClelland Laboratory for Water Chemistry and Environmental Analysis, published research in the journal Analytical and Bioanalytical Chemistry outlining their groundbreaking method that is able to detect 79 pesticide residues in human blood plasma ...
2023-04-06
BINGHAMTON, N.Y. -- Economically disadvantaged students face food scarcity, unreliable access to services and other stressors, which can have a huge impact on their mental health. In Broome and Tioga counties, more than 50% of children live in families characterized as low income. New federal funding will help to put more Binghamton University social work students in schools to provide the services that these students need to succeed.
The U.S. Department of Education has awarded two 5-year awards, totalling $9.3 million, to Binghamton University Community Schools (BUCS) to ...
2023-04-06
PROVIDENCE, R.I. [Brown University] — While new drugs to treat Alzheimer’s disease tend to receive the most public attention, many well-researched ways to care for people with dementia don’t involve medication. A new evaluation compared the cost-effectiveness of four non-drug interventions to the usual care received by people with dementia and found that the interventions not only resulted in a better quality of life, but also saved money.
In a study published April 6 in Alzheimer's & Dementia: ...
2023-04-06
The use of coal power is not decreasing fast enough. The Paris Agreement’s target of a maximum of 2 degrees of warming appear to be missed, and the world is moving towards a temperature increase of 2.5–3 degrees. At the same time it is feasible to avoid higher warming. This is shown by researchers from Chalmers University of Technology and Lund University, Sweden, in a new study.
“More and more countries are promising that they will phase out coal from their energy systems, which is positive. But ...
2023-04-06
Researchers with the Smithsonian’s National Museum of Natural History have discovered the first effective bacterial probiotic for treating and preventing stony coral tissue loss disease (SCTLD), a mysterious ailment that has devastated Florida’s coral reefs since 2014 and is rapidly spreading throughout the Caribbean.
The probiotic treatment, described in a paper published today in Communications Biology, provides an alternative to the use of the broad-spectrum antibiotic amoxicillin, which has so far been the only proven treatment for the disease but which runs the risk of promoting antibiotic-resistant bacteria.
SCTLD ...
LAST 30 PRESS RELEASES:
[Press-News.org] How to make better consistency and availability trade-offs in networks
New theorem benefits distributed system design
