Improved Approximation Bounds for Minimum Weight Cycle in the CONGEST Model

Minimum Weight Cycle (MWC) is the problem of finding a simple cycle of minimum weight in a graph $G=(V,E)$. This is a fundamental graph problem with classical sequential algorithms that run in $\tilde{O}(n^3)$ and $\tilde{O}(mn)$ time where $n=|V|$ and $m=|E|$. In recent years this problem has received significant attention in the context of hardness through fine grained sequential complexity as well as in design of faster sequential approximation algorithms. For computing minimum weight cycle in the distributed CONGEST model, near-linear in $n$ lower and upper bounds on round complexity are known for directed graphs (weighted and unweighted), and for undirected weighted graphs; these lower bounds also apply to any $(2-\epsilon)$-approximation algorithm. This paper focuses on round complexity bounds for approximating MWC in the CONGEST model: For coarse approximations we show that for any constant $\alpha >1$, computing an $\alpha$-approximation of MWC requires $\Omega (\frac{\sqrt n}{\log n})$ rounds on weighted undirected graphs and on directed graphs, even if unweighted. We complement these lower bounds with sublinear $\tilde{O}(n^{2/3}+D)$-round algorithms for approximating MWC close to a factor of 2 in these classes of graphs. A key ingredient of our approximation algorithms is an efficient algorithm for computing $(1+\epsilon)$-approximate shortest paths from $k$ sources in directed and weighted graphs, which may be of independent interest for other CONGEST problems. We present an algorithm that runs in $\tilde{O}(\sqrt{nk} + D)$ rounds if $k \ge n^{1/3}$ and $\tilde{O}(\sqrt{nk} + k^{2/5}n^{2/5+o(1)}D^{2/5} + D)$ rounds if $k<n^{1/3}$, and this round complexity smoothly interpolates between the best known upper bounds for approximate (or exact) SSSP when $k=1$ and APSP when $k=n$

The FAIR TRADE Framework for Assessing Decentralised Data Solutions

Decentralised data solutions bring their own sets of capabilities, requirements and issues not necessarily present in centralised solutions. In order to compare the properties of different approaches or tools for management of decentralised data, it is important to have a common evaluation framework. We present a set of dimensions relevant to data management in decentralised contexts and use them to define principles extending the FAIR framework, initially developed for open research data. By characterising a range of different data solutions or approaches by how TRusted, Autonomous, Distributed and dEcentralised, in addition to how Findable, Accessible, Interoperable and Reusable, they are, we show that our FAIR TRADE framework is useful for describing and evaluating the management of decentralised data solutions, and aim to contribute to the development of best practice in a developing field

A safety transport framework for hired coaches for school transport.

Safety in school transport is a critical issue which involves children who are the most vulnerable users of it. On an average 973 trips are made per person in a year, out of which 105 are on school runs. In the United Kingdom (UK) alone, 1218 children were injured in 381 coach crashes between 2005 and 2016. Driver errors or technical faults in vehicles were the most commonly reported contributory factors for coach accidents. Coaches are considered as the safest mode of transport for children, but coach accidents result in a high number of fatalities per accident as coaches carry more children compared to any other means of school transport. There are more than 24000 schools in England alone and each school makes at least two field trips per year, which is equivalent to 48000+ trips. Schools in the UK rely on coach operators to provide vehicles for short and long school trips. In the UK there are strict regulations on operator’s compliance with the government safety regulations. In last year alone, 78 coach operators’ licenses have been revoked without public inquiries in the UK due to operator’s non-compliance. Though the government has strict safety regulations, accidents are still happening. Most of the existing literature has focused on economical and shortest routes to transport children, but they do not consider the safety aspects of the coach operators, coaches and the drivers in terms of compliance with the government safety regulations. Proper selection of coach operator, coach and driver can considerably mitigate safety risks for school transport. Only limited studies have examined safety of children travelling by coaches in the UK. This research involves a thorough analysis of the existing literature, national accident statistics, government policies, and traffic commissioner’s report. Two surveys were conducted with stakeholders (parents, school headmasters, coach operators, coach drivers, council transport officers and road safety analysts) to identify safety-related issues and the requirements of stakeholders in coach-based school transport in the UK. The analysis of the outcome shows that there are significant safety issues exist and there is a requirement for a safety transport framework to support users of hired private coaches in the UK to transport schoolchildren. A novel safety transport framework for hired coaches is proposed to address the identified safety issues. The framework validates coach operators, their coaches and drives using safety scores, based on their track record. This information can be shared with the school headmasters and parents before booking coaches. The framework also provides recommendations to coach operators to improve their fleet safety. The framework is prototyped, and both the framework and the prototype were evaluated within the UK. The evaluation shows that the framework has achieved its intended objectives and received positive feedback from the stakeholders

COVID-19 Antibody Test/Vaccination Certification There’s an app for that

Goal: As the Coronavirus Pandemic of 2019/2020 unfolds, a COVID-19 ‘Immunity Passport’ has been mooted as a way to enable individuals to return back to work. While the quality of antibody testing, the avail- the ability of vaccines, and the likelihood of even attaining COVID-19 immunity continue to be researched, we address the issues involved in providing tamper-proof and privacy-preserving certification for test results and vaccinations. Methods: We developed a prototype mobile phone app and requisite decentralized server architecture that facilitates instant verification of tamper-proof test results. Personally identifiable information is only stored at the user’s discretion, and the app allows the end-user selectively to present only the specific test result with no other personal information revealed. The architecture, designed for scalability, relies upon (a) the 2019 World Wide Web Consortium standard called ‘Verifiable Credentials’, (b) Tim Berners-Lee’s decentralized personal data platform ‘Solid’, and (c) a Consortium Ethereum-based blockchain. Results: Our mobile phone app and decentralized server architecture enable the mixture of verifiability and privacy in a manner derived from public/private key pairs and digital signatures, generalized to avoid restrictive ownership of sensitive digital keys and/or data. Benchmark performance tests show it to scale linearly in the worst case, as significant processing is done locally on each app. For the test certificate Holder, Issuer (e.g. healthcare staff, pharmacy) and Verifier (e.g. employer), it is ‘just another app’ which takes only minutes to use. Conclusions: The app and decentralized server architecture offer a prototype proof of concept that is readily scalable, applicable generically, and in effect ‘waiting in the wings’ for the biological issues, plus key ethical issues raised in the discussion section, to be resolved

Towards A Blockchain-based Decentralised Educational Landscape

Institutions in the current educational landscape op- erate independently. They exhibit reluctance in sharing their teaching and qualifications with others due to the fear of dam- aging individuality. This practice, however, is counterproductive for the students as they suffer from various difficulties and get deprived of certain benefits. In this paper, we explore the possibility of finding a solution to this deadlock. We argue that Blockchain-based decentralisation can offer a passageway where educational institutions get to keep their individuality but participate in collaborations to help overcome the problems students undergo. Our principal contribution in this paper is a conceptual educational landscape to show how institutions could potentially manage record-keeping, credential verifications, and continued career support in a decentralised environment

Towards Complete Decentralised Verification of Data with Confidentiality: Different ways to connect Solid Pods and Blockchain

Over-centralisation of data leads to tampering and sharing user information without the consent of the owners. This problem has been studied extensively in recent times providing separate solutions involving distributed storage, Blockchain technology and Solid Pods. Individually these solutions are not sufficient to build realistic applications in a decentralised environment; however, a combination of them can effectively provide more powerful and useful use-cases. In this paper, we propose the methods of combining Solid Pods and distributed ledgers in introducing complete decentralisation of data with total user-control, keeping the integrity of the stored information intact through Blockchain-based verification. We demonstrated multiple configurations of our solutions, offering several new use-cases in various sectors. These configurations introduce new dimensions on the Web and mobile applications’ data storage that developers can benefit from building Distributed Applications (DApps) in a complete decentralised environment

A Framework for Handling Internet of Things Data with Confidentiality and Blockchain Support

The Internet of Things (IoT) has emerged as a disruptive technology in recent time. Due to a sharp rise in the deployment of IoT devices across the globe, the total amount of generated data reaching record highs every day. There is no denying that IoT devices with the data that they produce enhancing our day to day lives by bringing in innovative solutions. However, there is a darker side of this technology as it enables device manufacturers and service providers to retain this data that they can later use for several purposes, including targeted marketing. Unfortunately, not many people are aware of this data misuse by service providers. To address this issue, we propose a framework for the confidential handling of IoT data with Blockchain-based verification. We used a combination of Solid and Blockchain to accomplish this goal. Our experimental results show that the proposed approach is promising and has the potential to bring a considerable change in the IoT industry

A Safety Transport Model for Validation of UK Coach Operators for School Journeys

Coaches are considered to be one of the safest modes of transport for children in the UK. In the last 10 years alone, 1191 children were injured in 371 coach crashes. Though the government has strict regulations to maintain road worthiness of the coaches, operator non-compliance was the major reason for these accidents. In last year alone, 137 coach operator licenses have been revoked due to operator non-compliance in the UK. Currently, there is no process to reliably mitigate the safety risks of children travelling by coaches. This has created a requirement to validate all the coach operators before using their coaches for school trips. This paper proposes a novel safety model for validation of coach operators prior to commencement of coach journeys

Adtributor: Revenue Debugging in Advertising Systems

Abstract Advertising (ad) revenue plays a vital role in supporting free websites. When the revenue dips or increases sharply, ad system operators must find and fix the rootcause if actionable, for example, by optimizing infrastructure performance. Such revenue debugging is analogous to diagnosis and root-cause analysis in the systems literature but is more general. Failure of infrastructure elements is only one potential cause; a host of other dimensions (e.g., advertiser, device type) can be sources of potential causes. Further, the problem is complicated by derived measures such as costs-per-click that are also tracked along with revenue. Our paper takes the first systematic look at revenue debugging. Using the concepts of explanatory power, succinctness, and surprise, we propose a new multidimensional root-cause algorithm for fundamental and derived measures of ad systems to identify the dimension mostly likely to blame. Further, we implement the attribution algorithm and a visualization interface in a tool called the Adtributor to help troubleshooters quickly identify potential causes. Based on several case studies on a very large ad system and extensive evaluation, we show that the Adtributor has an accuracy of over 95% and helps cut down troubleshooting time by an order of magnitude

Evaluation of Real Time PCR Detection of the 47 kDa Gene for Reliable Diagnosis of Pediatric Scrub Typhus

Diagnosis of scrub typhus is difficult, because of its non-specific clinical features and a lack of reliable serological assays. This study assessed real time PCR detection of the 47 kDa gene along with routine IgM ELISA for confirmatory diagnosis of scrub typhus. This observational study was conducted between March 2021 and February 2023. Real time PCR detection of the 47 kDa gene was used as a diagnostic assay. Confirmed scrub typhus cases were defined by IgM ELISA and/or real time PCR positivity. A total of 105 children (0–18 years of age) were enrolled, 30 (28.57%) of whom were confirmed to have scrub typhus, according to IgM ELISA and/or real time PCR positivity. The clinical symptoms of scrub typhus positive children included fever, diarrhea, abdominal pain, breathing difficulties, lymphadenopathy, rash, headache, edema, seizure, and poor intake. Good statistical correlations were observed among real time scrub positivity, high grade fever of 8.2 days’ duration, the presence of eschar and thrombocytopenia. Non-specific respiratory symptoms; cough, and cold were more severe in patients with scrub typhus. The real time PCR test showed good specificity in discriminating scrub typhus from enteric fever, a common pediatric disease. Detection of the 47 kDa gene with real time PCR has good sensitivity and specificity. The number of days between fever onset and sampling, as well as the administration of antibiotics before sampling, influence the performance of real-time PCR