426 research outputs found

    Network Agnostic MPC with Statistical Security

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    We initiate the study of the network agnostic MPC protocols with statistical security. Network agnostic protocols give the best possible security guarantees irrespective of the underlying network type. We consider the general-adversary model, where the adversary is characterized by an adversary structure which enumerates all possible candidate subsets of corrupt parties. The Q(k)\mathcal{Q}^{(k)} condition enforces that the union of no kk subsets from the adversary structure covers the party set. Given an unconditionally-secure PKI setup, known statistically-secure synchronous MPC protocols are secure against adversary structures satisfying the Q(2)\mathcal{Q}^{(2)} condition. Known statistically-secure asynchronous MPC protocols can tolerate Q(3)\mathcal{Q}^{(3)} adversary structures. Fix a set of nn parties P={P1,...,Pn}\mathcal{P} = \{P_1, ... ,P_n\} and adversary structures Zs\mathcal{Z}_s and Za\mathcal{Z}_a, satisfying the Q(2)\mathcal{Q}^{(2)} and Q(3)\mathcal{Q}^{(3)} conditions respectively, where ZaZs\mathcal{Z}_a \subset \mathcal{Z}_s. Then, given an unconditionally-secure PKI, we ask whether it is possible to design a statistically-secure MPC protocol resilient against Zs\mathcal{Z}_s and Za\mathcal{Z}_a in a synchronous and an asynchronous network respectively if the parties in P\mathcal{P} are unaware of the network type. We show that it is possible iff Zs\mathcal{Z}_s and Za\mathcal{Z}_a satisfy the Q(2,1)\mathcal{Q}^{(2,1)} condition, meaning that the union of any two subsets from Zs\mathcal{Z}_s and any one subset from Za\mathcal{Z}_a is a proper subset of P\mathcal{P}. We design several important network agnostic building blocks with the Q(2,1)\mathcal{Q}^{(2,1)} condition, such as Byzantine broadcast, Byzantine agreement, information checking protocol, verifiable secret-sharing and secure multiplication protocol, whose complexity is polynomial in nn and Zs|\mathcal{Z}_s|

    Metastatic Bladder Cancer: A Review of Current Management

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    Bladder cancer continues to result in substantial morbidity and mortality for affected individuals. Advances in the management of metastatic bladder cancer have been limited. Chemotherapy with platinum-based regimes remains the mainstay of first-line treatment. Studies investigating alternative regimes have offered no survival advantage. Targeted therapies may offer benefit either as single agent or in combination with chemotherapy. Symptoms due to metastatic bladder cancer impact patients' quality of life, and therefore holistic management is vital. Such management includes radiotherapy, bisphosphonates, and the involvement of specialist palliative care services. This review will discuss the current management for metastatic bladder cancer, future potential treatment modalities, and the evidence to support the management strategies

    Using a literature based discovery approach to study moderating effects and preventive mechanisms of online game addiction problems among gamers

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    This research makes use of a hypothesis generation technique known as Literature-Based Discovery (LBD) to study certain under-researched topics related to online game addiction problems in our society. This research work tries to primarily address two problems related to game addiction which have been under-studied according to the literature available on this topic. In the first problem, we try to identify certain moderating factors of massively multiplayer games which weakens the relationship between the psychological flow state and game addiction. In this data-driven approach, we studied 2829 abstracts to generate a list of keywords that suggest potential moderating factors for MMO games. Then interview data from 3 domain experts are used to support our findings from the LBD method. The results suggest that the keywords help us to identify alternative pathways (e.g., escapism, cognitive mechanisms and identification with avatars) to game addiction which have received less research attention. In the second problem, we tried to identify potentially effective but under-studied measures that help prevent the negative effects of online game addiction among children and adolescents. We searched the abstracts of 876 articles using Literature-Based discovery and applied association rule mining to identify negative effects and preventive mechanisms of game addiction among children and adolescents in the age group of 8-19. We then tried to rank the relationship between these negative effects and preventive mechanisms by using the measure of ‘w-support’. This helped us identify some preventive mechanisms which have been under-studied in the game addiction literature along with the corresponding negative effects they address. Finally, we have computed the effective size of one such under-studied preventive mechanism to show that it is equally effective as other popular preventive mechanisms. This approach gives us an important future direction in the study and design of preventive programs to address online game addiction issues. In both the problems, we use LBD methodology to either identify alternative pathways to supplement a more popular theory, as in the MMO game study or we used LBD to suggest some under-studied relationships, that can be further explored to design effective preventive mechanisms of online game addiction in children and adolescents. Thus, with the help of LBD as a research methodology, we try to overcome the challenges of knowledge overspecialization in certain areas and identify important future directions of research on the causes and prevention of online game addiction

    Perfectly Secure Synchronous MPC with Asynchronous Fallback Guarantees Against General Adversaries

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    In this work, we study perfectly-secure multi-party computation (MPC) against general (non-threshold) adversaries. Known protocols in a synchronous network are secure against Q(3)Q^{(3)} adversary structures, while in an asynchronous network, known protocols are secure against Q(4)Q^{(4)} adversary structures. A natural question is whether there exists a single protocol which remains secure against Q(3)Q^{(3)} and Q(4)Q^{(4)} adversary structures in a synchronous and in an asynchronous network respectively, where the parties are not aware of the network type. We design the first such best-of-both-worlds protocol against general adversaries. Our result generalizes the result of Appan, Chandramouli and Choudhury (PODC 2022), which presents a best-of-both-worlds perfectly-secure protocol against threshold adversaries. To design our protocol, we present two important building blocks which are of independent interest. The first building block is a best-of-both-worlds perfectly-secure Byzantine agreement (BA) protocol for Q(3)Q^{(3)} adversary structures, which remains secure both in a synchronous, as well as an asynchronous network. The second building block is a best-of-both-worlds perfectly-secure verifiable secret-sharing (VSS) protocol, which remains secure against Q(3)Q^{(3)} and Q(4)Q^{(4)} adversary structures in a synchronous network and an asynchronous network respectively

    Perfectly-Secure Synchronous MPC with Asynchronous Fallback Guarantees

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    Secure multi-party computation (MPC) is a fundamental problem in secure distributed computing. An MPC protocol allows a set of nn mutually distrusting parties to carry out any joint computation of their private inputs, without disclosing any additional information about their inputs. MPC with information-theoretic security (also called unconditional security) provides the strongest security guarantees and remains secure even against computationally unbounded adversaries. Perfectly-secure MPC protocols is a class of information-theoretically secure MPC protocols, which provides all the security guarantees in an error-free fashion. The focus of this work is perfectly-secure MPC. Known protocols are designed assuming either a synchronous or an asynchronous communication network. It is well known that perfectly-secure synchronous MPC protocol is possible as long as adversary can corrupt any ts<n/3t_s < n/3 parties. On the other hand, perfectly-secure asynchronous MPC protocol can tolerate up to ta<n/4t_a < n/4 corrupt parties. A natural question is does there exist a single MPC protocol for the setting where the parties are not aware of the exact network type and which can tolerate up to ts<n/3t_s < n/3 corruptions in a synchronous network and up to ta<n/4t_a < n/4 corruptions in an asynchronous network. We design such a best-of-both-worlds perfectly-secure MPC protocol, provided 3ts+ta<n3t_s + t_a < n holds. For designing our protocol, we design two important building blocks, which are of independent interest. The first building block is a best-of-both-worlds Byzantine agreement (BA) protocol tolerating t<n/3t < n/3 corruptions and which remains secure, both in a synchronous as well as asynchronous network. The second building block is a polynomial-based best-of-both-worlds verifiable secret-sharing (VSS) protocol, which can tolerate up to tst_s and tat_a corruptions in a synchronous and in an asynchronous network respectively

    Annotation of existing databases using Semantic Web technologies:Making data more FAIR

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    Making data FAIR is an elaborate task. Hospitals and/or departments have to invest into technologies usually unknown and often do not have the resources to make data FAIR. Our work aims to provide a framework and tooling where users can easily make their data (more) FAIR. This framework uses RDF and OWL-based inferencing to annotate existing databases or comma-separated files. For every database, a custom ontology is build based on the database schema, which can be annotated to describe matching standardized terminologies. In this work, we describe the tooling developed, and the current implementation in an institutional datawarehouse pertaining over 3000 rectal cancer patients. We report on the performance (time) of the extraction and annotation process by the developed tooling. Furthermore, we do show that annotation of existing databases using OWL2-based reasoning is possible. Furthermore, we show that the ontology extracted from existing databases can provide a description framework to describe and annotate existing data sources. This would target mostly the “Interoperable” aspect of FAIR

    An unusual case of oedematous prostate volumetric changes observed over the course of radiotherapy on the MR linear accelerator

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    IntroductionThe integration of magnetic resonance (MR) imaging into radiotherapy through new technology, including the MR -linear accelerator (MRL), has allowed further advancements into image guided radiotherapy (IGRT). Better soft tissue visualisation has led to some unusual findings.Case and outcomesA patient with T1c N0 M0 prostate adenocarcinoma received 60Gy in 20# radiotherapy on the MRL. Radiotherapy planning (RTP) scans were completed on both CT and MR (using T2 and T1 weighted three-dimensional turbo spin echo sequences, reconstructed transaxially (TRA). The MR scans revealed atypical oedema in the right peripheral zone, visualised on T2-weighted (T2w) MR Images as an accumulation of high signal intensity fluid. Daily MRL treatment includes a (T2w 3D Tra) sequence with which oedematous changes could be monitored. The images demonstrated an increase in oedematous volume over fractions 1-10 causing the prostate contour variations from the initial planning scans. Despite the prostate volume variations PTV coverage was never breached and dose constraints were always met for both PTV and surrounding organs at risk (OAR's), excluding the need for oncologist input. A single Therapeutic Radiographer (RTT) experienced in MRL delivery, contoured the prostate and oedematous volumes on the radiotherapy plan (RTP) MR and all on-treatment MR images to assess change over the radiotherapy course. The initial volumes were 53.4 cm3 and 8.3 cm3 for the prostate plus oedema and oedema alone respectively. The most significant change was seen for both the prostate and oedema on fraction nine (68.0 cm3 and 10.1 cm3, respectively). Reductions were noted after this with final (fraction 20) volumes of 55.2 cm3 and 0.58 cm3 respectively.DiscussionThe ability to visualise prostatic oedema was new to the radiotherapy treatment team due to better soft tissue visualisation than standard radiotherapy. The results from contouring the prostate and oedema volumes confirmed radiographer observations and demonstrated how oedema impacted the overall prostate volume by quantifying the oedematous variations over time. The changes in oedema volume are presumed to be in response to radiotherapy.ConclusionFurther adaptive radiotherapy work-flow developments, utilising an "Adapt to Shape" model will allow real-time re-contouring of the prostate to ensure tumour control is not compromised. Further work investigating the frequency and impact of oedemotous changes to external beam prostate patients will help to inform practice

    Recurrence patterns of locally advanced head and neck squamous cell carcinoma after 3D conformal (chemo)-radiotherapy

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    <p>Abstract</p> <p>Background</p> <p>To establish recurrence patterns among locally advanced head and neck non-nasopharyngeal squamous cell carcinoma (HNSCC) patients treated with radical (chemo-) radiotherapy and to correlate the sites of loco-regional recurrence with radiotherapy doses and target volumes</p> <p>Method</p> <p>151 locally advanced HNSCC patients were treated between 2004-2005 using radical three-dimensional conformal radiotherapy. Patients with prior surgery to the primary tumour site were excluded. The sites of locoregional relapses were correlated with radiotherapy plans by the radiologist and a planning dosimetrist.</p> <p>Results</p> <p>Median age was 59 years (range:34-89). 35 patients had stage III disease, 116 patients had stage IV A/B. 36 patients were treated with radiotherapy alone, 42 with induction chemotherapy, 63 with induction and concomitant chemoradiotherapy and 10 concomitant chemoradiotherapy. Median follow-up was 38 months (range 3-62). 3-year cause specific survival was 66.8%. 125 of 151 (82.8%) achieved a complete response to treatment. Amongst these 125 there were 20 local-regional recurrence, comprising 8 local, 5 regional and 7 simultaneous local and regional; synchronous distant metastases occurred in 7 of the 20. 9 patients developed distant metastases in the absence of locoregional failure. For the 14 local recurrences with planning data available, 12 were in-field, 1 was marginal, and 1 was out-of-field. Of the 11 regional failures with planning data available, 7 were in-field, 1 was marginal and 3 were out-of-field recurrences.</p> <p>Conclusion</p> <p>The majority of failures following non-surgical treatment for locally advanced HNSCC were loco-regional, within the radiotherapy target volume. Improving locoregional control remains a high priority.</p

    Applying federated learning to combat food fraud in food supply chains

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    Ensuring safe and healthy food is a big challenge due to the complexity of food supply chains and their vulnerability to many internal and external factors, including food fraud. Recent research has shown that Artificial Intelligence (AI) based algorithms, in particularly data driven Bayesian Network (BN) models, are very suitable as a tool to predict future food fraud and hence allowing food producers to take proper actions to avoid that such problems occur. Such models become even more powerful when data can be used from all actors in the supply chain, but data sharing is hampered by different interests, data security and data privacy. Federated learning (FL) may circumvent these issues as demonstrated in various areas of the life sciences. In this research, we demonstrate the potential of the FL technology for food fraud using a data driven BN, integrating data from different data owners without the data leaving the database of the data owners. To this end, a framework was constructed consisting of three geographically different data stations hosting different datasets on food fraud. Using this framework, a BN algorithm was implemented that was trained on the data of different data stations while the data remained at its physical location abiding by privacy principles. We demonstrated the applicability of the federated BN in food fraud and anticipate that such framework may support stakeholders in the food supply chain for better decision-making regarding food fraud control while still preserving the privacy and confidentiality nature of these data
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