Elections conducted on paper consume a lot of resources and contribute to the destruction of forests, which leads to climate deterioration. Moreover, such election process can make it difficult for some people to vote and it often leads to doubts in the validity of counting, in people submitting multiple votes, in ineligible people voting. In several well-known previous examples, doubts in the validity of paper elections lead to the need of recounting and even court battles to decide the validity of the outcome. Having a way to vote online could be an easier and more reliable solution. However, secure and verifiable methods of online voting need to be developed to achieve this.<br><br>Recent online voting experiences in countries such as the United States, India and Brazil demonstrated that further research is needed to improve security guarantees for future elections, to ensure the confidentiality of votes and enable the verification of their integrity and validity. Electronic voting, to be successful, requires a more transparent and secure approach, than the approach that is offered by current electronic voting protocols. Advanced security methods are necessary to introduce effective online voting in the whole world.<br><br>Currently, most online voting systems are centralized, which means that they involve central tallying authorities to take responsibility for verifying, tallying and publishing the final outcome of the election. These previous systems always assume that their central authorities are honest. Otherwise, the published final outcome cannot be trusted. The aim of our new research is to propose and investigate a decentralized ranked choice online voting systems, which never rely on any third party (such as tallying authorities), thereby significantly increasing the confidence and trust of the voters.<br><br>The thesis presents several publicly verifiable online voting systems and indicates the processing steps and stages in the development of a publicity verifiable online voting system from centralized to semi-decentralized, to fully decentralized. By using Homomorphic cryptosystem, proof of zero knowledge and Blockchain technology, the proposed system in this thesis can achieve the following: (1) Flexible voting mechanism: voters can easily rank all candidates; (2) Publicity verifiable: the whole election procedure is transparent and verifiable by voters; (3) Self-tallying: the final outcome of the election can be computed by any individual voter; and (4) Fully decentralized: no tallying authority (or any other trusted third party) involved at all.<br><br>The proposed systems presented in this thesis include protocols developed on Blockchain technology. The technology that is used as the basis for a secure online voting system is ``smart contract over Blockchain', which offers a factor of the integrity of votes and has not been deeply studied in Blockchain technologies to date. The proposed voting protocols ensure confidentiality and preserve the voters' privacy while keeping the election procedures transparent and secure. The underlying Blockchain protocol has not been modified in any way, the voting scheme proposed merely offers an alternative use case of the protocol at hand, which could be presented as the basis for voting systems using Blockchain with further development of the underlying Blockchain protocols.<br><br>
Yunhui Long, Tanmay Gangwani, Haris Mughees, Carl A. Gunter
Privacy preserving multi-party computation has many applications in areas such as medicine and online advertisements. In this work, we propose a framework for distributed, secure machine learning among untrusted individuals. The framework consists of two parts: a two-step training protocol based on homomorphic addition and a zero knowledge proof for data validity. By combining these two techniques, our framework provides privacy of per-user data, prevents against a malicious user contributing corrupted data to the shared pool, enables each user to self-compute the results of the algorithm without relying on external trusted third parties, and requires no private channels between groups of users. We show how different ML algorithms such as Latent Dirichlet Allocation, Naive Bayes, Decision Trees etc. fit our framework for distributed, secure computing.
Lei Wang, Haining Wang, Ying-fei CHAO, Shuhong Shi · 5 authors
This paper discussed the application of blockchain technology in power trading business, and focused on solving the information security problems which currently faced by power trading, including protecting the privacy of market entities, encrypting key data. This paper proposes the idea of controlling user access through CA nodes, using zero-knowledge proof mechanism to protect user privacy, and adopting pluggable way to set consensus mechanism. This paper proposes an innovative vision for building a power trading blockchain, providing advice for future power trading blockchains.
We study an unsteady nonlinear fluidâstructure interaction problem. We consider a Newtonian incompressible two-dimensional flow described by the NavierâStokes equations set in an unknown domain depending on the displacement of a structure, which itself satisfies a linear wave equation or a linear beam equation. The fluid and the structure systems are coupled via interface conditions prescribing the continuity of the velocities at the fluidâstructure interface and the action-reaction principle. Considering three different structure models, we prove existence of a unique local-in-time strong solution, for which there is no gap between the regularity of the initial data and the regularity of the solution enabling to obtain a blow up alternative. In the case of a damped beam this is an alternative proof (and a generalization to non zero initial displacement) of the result that can be found in [20]. In the case of the wave equation or a beam equation with inertia of rotation, this is, to our knowledge the first result of existence of strong solutions for which no viscosity is added. The key points consist in studying the coupled system without decoupling the fluid from the structure and to use the fluid dissipation to control, in appropriate function spaces, the structure velocity.
Open access
Navier-Stokes equation solutions
Stability and Controllability of Differential Equations
Recently, Autonomous Vehicles (AVs) have gained extensive attention from both academia and industry. AVs are a complex system composed of many subsystems, making them a typical target for attackers. Therefore, the firmware of the different subsystems needs to be updated to the latest version by the manufacturer to fix bugs and introduce new features, e.g., using security patches. In this paper, we propose a distributed firmware update scheme for the AVs' subsystems, leveraging blockchain and smart contract technology. A consortium blockchain made of different AVs manufacturers is used to ensure the authenticity and integrity of firmware updates. Instead of depending on centralized third parties to distribute the new updates, we enable AVs, namely distributors, to participate in the distribution process and we take advantage of their mobility to guarantee high availability and fast delivery of the updates. To incentivize AVs to distribute the updates, a reward system is established that maintains a credit reputation for each distributor account in the blockchain. A zero-knowledge proof protocol is used to exchange the update in return for a proof of distribution in a trust-less environment. Moreover, we use attribute-based encryption (ABE) scheme to ensure that only authorized AVs will be able to download and use a new update. Our analysis indicates that the additional cryptography primitives and exchanged transactions do not affect the operation of the AVs network. Also, our security analysis demonstrates that our scheme is efficient and secure against different attacks.
One major shortcoming of permissionless blockchains such as Bitcoin and Ethereum is that they are unsuitable for running Computationally Intensive smart Contracts (CICs). This prevents such blockchains from running Machine Learning algorithms, Zero-Knowledge proofs, etc. which may need non-trivial computation. In this paper, we present YODA, which is to the best of our knowledge the first solution for efficient computation of CICs in permissionless blockchains with guarantees for a threat model with both Byzantine and selfish nodes. YODA selects one or more execution sets (ES) via Sortition to execute a particular CIC off-chain. One key innovation is the MultI-Round Adaptive Consensus using Likelihood Estimation (MIRACLE) algorithm based on sequential hypothesis testing. M I RACLE allows the execution sets to be small thus making YODA efficient while ensuring correct CIC execution with high probability. It adapts the number of ES sets automatically depending on the concentration of Byzantine nodes in the system and is optimal in terms of the expected number of ES sets used in certain scenarios. Through a suite of economic incentives and technical mechanisms such as the novel Randomness Inserted Contract Execution (RICE) algorithm, we force selfish nodes to behave honestly. We also prove that the honest behavior of selfish nodes is an approximate Nash Equilibrium. We present the system design and details of YODA and prove the security properties of MIRACLE and RICE. Our prototype implementation built on top of Ethereum demonstrates the ability of YODA to run CICs with orders of magnitude higher gas per unit time as well as total gas requirements than Ethereum currently supports. It also demonstrates the low overheads of RICE.
As cities become more digitally governed, centralized infrastructures face growing risks across identity, safety, and data domains. This chapter reframes blockchain as a foundational trust protocol for urban resilience, emphasizing its core features: immutability, decentralization, transparency, and consensus, as tools to address systemic privacy and security challenges. It explores blockchain's role in securing digital identities, logging infrastructure events, and enabling auditable governance. Real-world deployments in land registries, voting, procurement, and incident response, especially in Asia and Europe are analyzed. Privacy-preserving techniques like zero-knowledge proofs and decentralized identity are also examined. The chapter highlights integration hurdles such as interoperability, regulatory gaps, and ethical tensions, while outlining emerging trends like Blockchain 4.0, quantum-safe cryptography, and DAO-led civic participation. It offers a roadmap for decentralized citizen-centric governance in smart cities.
Post-Quantum Cryptography (PQC) attempts to find cryptographic protocols resistant to attacks using Shor polynomial time algorithm for numerical field problems or Grover search algorithm. A mostly overlooked but valuable line of solutions is provided by non-commutative algebraic structures, specifically canonical protocols that rely on one-way trapdoor functions (OWTF). Here we develop an algebraic framework who could be applied to different asymmetric protocols like D-H KE (Diffie-Hellman key exchange), Public Key Encryption, Digital Signature, ZKP (zero-knowledge proof) authentication, Oblivious Transfer, Multi-Party Computing, and so on. The trapdoor one-way functions selected are (a) Triple decomposition Problem (TDP) developed by Kurt, where a known element is factored into a product of three unknown factors and (b) a new version of conjugacy search that we refer from now on as Blind Conjugacy Search Problem (BCSP). Our platform structure is the general linear group GL(d,F_p) d-square non-singular matrices of prime field values. We give support to the fact that this framework is cryptographically secure against classical attacks like linear algebra attacks, length-based attacks, side-channel attacks against square (or duplicate) and multiply (or sum) algorithm, high sensitivity to pseudo random deterministic generators, etc. At same time it is immune against quantum attacks (using Grover and Shor), if the size parameters are carefully selected. Semantic security and IND-CCA2 compliance for this framework is discussed.
Rosario Gennaro, Michele Minelli, Anca Nitulescu, Michele OrrĂč
Zero-knowledge SNARKs (zk-SNARKs) are non-interactive proof systems with short and efficiently verifiable proofs. They elegantly resolve the juxtaposition of individual privacy and public trust, by providing an efficient way of demonstrating knowledge of secret information without actually revealing it. To this day, zk-SNARKs are being used for delegating computation, electronic cryptocurrencies, and anonymous credentials. However, all current SNARKs implementations rely on pre-quantum assumptions and, for this reason, are not expected to withstand cryptanalitic efforts over the next few decades. In this work, we introduce the first designated-verifier zk-SNARK based on lattice assumptions, which are believed to be post-quantum secure. We provide a generalization in the spirit of Gennaro et al. (Eurocrypt'13) to the SNARK of Danezis et al. (Asiacrypt'14) that is based on Square Span Programs (SSPs) and relies on weaker computational assumptions. We focus on designated-verifier proofs and propose a protocol in which a proof consists of just 5 LWE encodings. We provide a concrete choice of parameters as well as extensive benchmarks on a C implementation, showing that our construction is practically instantiable.
I wish to begin by thanking the people who nominated me for the Leonard medal and the Leonard Medal Committee of the Meteoritical Society for granting me this award. Thanks as well to Francois Robert for doing a fine job on the citation and his kind words. I have been a member of the Meteoritical Society and attended the meetings since I was a postdoctoral fellow at Chicago. The recognition by the society means a great deal to me and it is an honor to receive the Leonard Medal. I know most of the recipients over many decades and I am being included with a prestigious group. My research career in Meteoritics and Planetary Science began with my going to Chicago to work with Bob Clayton on nitrogen isotopes in the solar wind as detected by extraction from lunar samples. It was a lucky break for me that Bob had an opening for a post doc in the window of time when I was graduating and looking. Chicago was, and is, a center of research activity in meteorites and planetary science. My interest in the field dates to my last course at the University of Miami when I took a course titled âModern Geologyâ taught by Cesare Emiliani who was a student of Urey's. I had taken all the available physics and chemistry courses and wanted another science course. My interest in geology dated back to my childhood, when I belonged to the Gem and Mineral club at Washington University. This was a first-class organization wherein I learned a lot and attended monthly lectures with my dad and the whole family went on the many field trips they organized. Emiliani's course turned out to be the best course I took and he was an amazing teacher and mentor. It was in this broad ranging course that I learned of the application of both stable and radioactive isotopes to interpret processes in nature, ranging from the age of the Earth to paleoclimates, a field he helped found. It greatly impressed me that one could apply the fundamental physics and chemistry I had learned to quantitatively interpret differing geochemical records. I was struck by Urey's 1947 paper on the thermodynamics of isotopic substances and how one could use the information for. Emiliani brought me to his laboratory and showed me his mass spectrometer built at the University of Chicago before he came to Miami. A second significant impact on my scientific direction resulted from a course I took at Florida State from Gary Brass. He discussed the famous paper of Clayton et al. (1973) on the discovery of oxygen mass independent isotopic anomalies in meteoritic inclusions. I was very impressed with the fact that one could distinguish between nuclear processes and chemical by measurement of the multi-isotopes of oxygen and potentially identify individual grains that may have predated the solar system. As I neared completion of my doctoral work, which was finished at Brookhaven National Laboratory, I wrote to Bob Clayton about the possibility of postdoctoral work with him. I told him that I had experience in measuring oxygen and sulfur isotopes, as well as accelerator use for my PhD dissertation. He had an opening and I was able to join the Chicago group, which I had heard about from Emiliani when he discussed his own classmatesâ research (Wasserburg, Craig, Epstein, and Miller) and his work with Urey. My timing for coming to Chicago for meteoritic research could not have been better. Bob Clayton, Larry Grossman, Ed Anders, and Frank Richter were all engaged in meteoritic research; all of whom became Leonard medalists. It provided the opportunity to sit in on graduate courses by S. Chandrasekhar and Dave Schramm as well as geophysical, physical chemical, and astrophysical seminars by the world's best. The timing was also perfect as a large of of my own and were a great to with and for As was for many of I was also to have the opportunity to work with by to Urey's laboratory and with Bob when came to had taught laboratory research to many before me many as Craig, and my Cesare who the of the Clayton laboratory know how was for the and in with science they were doing The was a for and it was a time to be able to have a to and over the course of my my at the University of a for in the of to one of the of and well for many was a at the University of and a as was his work was on the of the and in and for of the and and also a Leonard work on and the of the in and was of fundamental was one of and the in physics at for the work at Chicago. 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A of the sulfur anomalies is the of the sulfur from of in from the in et al. sulfur anomalies were to the in the the The potentially of in the and on the of the The of the from sulfur anomalies a of and of how sulfur anomalies in the Earth from and laboratory and in the of sulfur and oxygen been the of sulfur anomalies from the of in a of a by and the of a chemical the and began a of measurement of in the for oxygen isotopic to in the oxygen isotopes and was in and he brought this to group. sulfur isotopic anomalies in with the and and an in et al. The isotopic is from as in the with recognition that the of oxygen an on chemical is a of a of the in a of and to to that work, been a of of sulfur isotopic anomalies in with et al. et al. was the to that could the to a and included oxygen which of the et al. and et al. his doctoral work with and went to the to a to in to the anomalies of sulfur at time et al. He also the of in by laboratory et al. 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The mass independent sulfur isotopic anomalies that in the for and and and in a the his PhD work, detected oxygen anomalies in and et al. et al. that all of the sulfur anomalies mass the sulfur anomalies not in the post from as by the with which is a et al. detected sulfur isotopic anomalies in the and also sulfur anomalies in from in the The that the is with and the of a and a significant is to this it is a of to The to both the and is that is a stable and by in and may be as well as solar and work in and chemistry is potentially sulfur isotopes have provided information on the to The of is in the by on The and was by et al. of the was to from in et al. The of and in a to interpret as it an in the of the have measurement at and from a of et al. et al. the of to were activity of both of sulfur at and on the helped and the provided the of a to in A sulfur isotopic measurement of from a provided how sulfur isotopes and over time and The of the was by of the et al. and of et al. 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My when I was of the and was a great and famous that he As a student of a of the of and of to and a and the he was in a lot of the of science. 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We are pleased to publish the second issue of the Global Journal on Quality and Safety in Healthcare (JQSH). In this issue, we would like to discuss the similarities and differences between research and quality improvement (QI) projects in health care. Imagine you are working in a hospital or a department within a hospital and you want to improve an aspect of health-care quality and safety by focusing on the issue of medication errors. Given that situation, you decide to implement a âzero harmâ rule because of medication errors. The question is will this be a QI or a research project? In another example, you are a resident working in an oncology department and you noticed that most patients receiving certain chemotherapeutic agents had neuropathy complications, so you decided to collaborate with the physical therapist on a project to compare patients who received chemotherapy drugs and exercise with those who did not exercise. Again, the question is will this be a research project or a QI project? Regardless of the answer, it is important to implement the project systematically. If your project is focused on QI, then you should consult the QI specialists in your hospital who can help you to use the appropriate QI methodology, which includes Plan, Do, Study, Act (PDSA) cycles. If your project qualifies as research, then you should consult a research methodologist and biostatistician regarding study design, sample size, and others and work with the institutional review board (IRB) to provide guidance and templates.Many health professionals do not know how a research project differs from a QI project and when they complement each other.[1â3] Our traditional thinking is that quality and safety improvement in health care as well as the effectiveness of an intervention can only be studied in the form of a traditional scientific research project, as it has its own well-established rigorous approach. We may be ignorant or unaware of how to use the QI scientific approach to study the performance of a health-care system.[4,5] The problem lies within our frame of thinking because we are prioritizing the proof of effectiveness over bringing about and sustaining improvement. We use the results of pre-assessment and post-assessment research as the gold standard for evidence-based policy and practice, whereas in reality, sustaining the improvement is continuous and more dynamic.[1,6]Research projects are question-driven and focus on providing proof of effectiveness. The main purpose of research is to generate new generalizable knowledge about a particular subject to a study population, where the study results often end up published in academic journals. In this case, researchers must follow a strict study protocol approved by the IRB, including obtaining the consent from study participants before starting the project and report any deviation from the protocol to the IRB, if needed.[7â9] However, QI projects are data-driven and focus on showing sustained improvement to a specific process and system or outcomes within a health-care organization using, if possible, the research evidence generated as the basis for developing the improvement interventions.[10] A QI project does not aim to generate new knowledge as a research project does, rather, it generates several learning lessons as to what actually works and does not work and why. A QI project produces empirical evidence to benefit other organizations within a similar context and setting, which are interested in replicating the change to improve a process or system using the rapid PDSA cycle approach.[11] Through cycles of testing, we learn what is going to improve and why, without the need to generalize the results to another context, as research projects usually aim to do. Also in QI projects, the measurement framework is not about pre and post. It is about continually measuring the metric of interest that you want to improve and coming up with not just one intervention but multiple interventions based on learning from prior PDSA cycles. At the end, you reach the point of realizing sustained improvement through a series of interventions that were informed by testing in the actual system that you want to improve. The PDSA cycle is repeated, and new changes are made to continue to improve a process and, ultimately, the outcome. The essential measurements included in a QI project are process measures, outcomes measures, and balancing measures, which are used to show that the improvement occurs over time. Data from QI activities are usually aggregated and presented in run/control charts, histograms, and line graphs, whereas data from research are analyzed using statistical tests such as t-test, chi-square test, and regression analysis, and then aggregated and presented in appropriate tables and/or graphs.Typically, QI results are shared within the organization and might be implemented in other departments. The lessons learned from QI activities can be published; however, it must be clear to the readers that the project was for QI, not traditional research. Although a QI project does not require IRB approval, some organizations have QI committees that approve and coordinate QI project activities, and some organizations require articles to be approved before submitting for publication.In summary, the sustained improvement realized in a QI project can be complemented and validated with a thorough research-based assessment of effectiveness.[12] We should not consider the proof of effectiveness the same as the proof of sustained improvement, but they both are very important. I would like to emphasize that both research and QI projects use scientific and systematic approaches, albeit different, but both methods are scientific and rigorous in their own ways. The aims, methods, and outcomes in research and QI projects are quite different. Hence, understanding the differences and similarities between research and QI projects will help to determine the right approach when designing and implementing the right project for the right purpose using the right method. Table 1 is a snapshot comparison between QI and research with more focus on the project's aim and method aspects.In research projects, we can be guided by asking the following: Do we have a clear question to be investigated and answered?What do we hope to accomplish by answering the question?What is currently known about the topic?What are the risks and benefits for patients involved with the study of this topic?What type of study design will be used (observational vs. experimental)?How will the data be analyzed and presented (statistical tests, P-values, etc.)?In QI projects, we can ask the following: What is the magnitude of the quality problem based on available data?What types of quality tools have been used to measure and assess the problem?What is the measurement plan to be used during implementation of the project?What types of changes/interventions will be tested during the PDSA cycles?Has the proposed change/intervention been used in other health-care settings or reported in the literature?Will the results of this project directly improve patient-care outcomes or processes?Is the organization's management supportive of the project and willing to dedicate employee's time and supplies to do the project?What is the sustainability plan for the results?
Open access
Health Systems, Economic Evaluations, Quality of Life
Privacy of blockchains has been a matter of discussion since the inception of Bitcoin. Various techniques with a varying degree of privacy protection and complexity have been proposed over the past decade. In this survey, we present a systematic analysis of these proposals in four categories: (i) identity, (ii) transaction, (iii) consensus, and (iv) smart contract privacy. Each of these categories have privacy requirements of its own, and various solutions have been proposed to meet these requirements. Almost every technique in the literature of privacy enhancing technologies have been applied to blockchains: mix networks, zero-knowledge proofs, blind signatures, ring signatures, secure MPC, homomorphic encryption, to name just a few. We analyze each category separately in the paper. We first define the related privacy issues, and then review the proposed solutions. The limitations of each solution and the attacks discovered are also discussed along with the proposals. For each category, we first define the relevant privacy issues, and then review the proposed solutions along with their features and limitations
Abelian cellular automata (CAs) are CAs which are group endomorphisms of the full group shift when endowing the alphabet with an abelian group structure. A CA randomizes an initial probability measure if its iterated images have weak*-convergence towards the uniform Bernoulli measure (the Haar measure in this setting). We are interested in structural phenomena, i.e., randomization for a wide class of initial measures (under some mixing hypotheses). First, we prove that an abelian CA randomizes in CesĂ ro mean if and only if it has no soliton, i.e., a non-zero finite configuration whose time evolution remains bounded in space. This characterization generalizes previously known sufficient conditions for abelian CAs with scalar or commuting coefficients. Second, we exhibit examples of strong randomizers, i.e., abelian CAs randomizing in simple convergence; this is the first proof of this behaviour to our knowledge. We show, however, that no CA with commuting coefficients can be strongly randomizing. Finally, we show that some abelian CAs achieve partial randomization without being randomizing: the distribution of short finite words tends to the uniform distribution up to some threshold, but this convergence fails for larger words. Again this phenomenon cannot happen for abelian CAs with commuting coefficients.
We consider the problem of single-round private information retrieval (PIR) from N replicated databases. We consider the case when B databases are outdated (unsynchronized), or even worse, adversarial (Byzantine), and therefore, can return incorrect answers. In the PIR problem with Byzantine databases (BPIR), a user wishes to retrieve a specific message from a set of M messages with zero-error, irrespective of the actions performed by the Byzantine databases. We consider the T-privacy constraint in this paper, where any T databases can collude, and exchange the queries submitted by the user. We derive the information-theoretic capacity of this problem, which is the maximum number of correct symbols that can be retrieved privately (under the T-privacy constraint) for every symbol of the downloaded data. We determine the exact BPIR capacity to be C = (N -2B)/N·(1-T/(N-2B))/(1-(T/(N - 2B))M), if 2B + T <; N. This capacity expression shows that the effect of Byzantine databases on the retrieval rate is equivalent to removing 2B databases from the system, with a penalty factor of (N - 2B)/N, which signifies that even though the number of databases needed for PIR is effectively N - 2B, the user still needs to access the entire N databases. The result shows that for the unsynchronized PIR problem, if the user does not have any knowledge about the fraction of the messages that are missynchronized, the single-round capacity is the same as the BPIR capacity. Our achievable scheme extends the optimal achievable scheme for the robust PIR (RPIR) problem to correct the errors introduced by the Byzantine databases as opposed to erasures in the RPIR problem. Our converse proof uses the idea of the cut-set bound in the network coding problem against adversarial nodes.
In this paper, we propose a new method to perform Sparse Kernel Principal Component Analysis (SKPCA) and also mathematically analyze the validity of SKPCA. We formulate SKPCA as a constrained optimization problem with elastic net regularization (Hastie et al.) in kernel feature space and solve it. We consider outlier detection (where KPCA is employed) as an application for SKPCA, using the RBF kernel. We test it on 5 real-world datasets and show that by using just 4% (or even less) of the principal components (PCs), where each PC has on average less than 12% non-zero elements in the worst case among all 5 datasets, we are able to nearly match and in 3 datasets even outperform KPCA. We also compare the performance of our method with a recently proposed method for SKPCA by Wang et al. and show that our method performs better in terms of both accuracy and sparsity. We also provide a novel probabilistic proof to justify the existence of sparse solutions for KPCA using the RBF kernel. To the best of our knowledge, this is the first attempt at theoretically analyzing the validity of SKPCA.
Ross Guttromson, Stephen Verzi, Lon Andrew Dawson, Drew Levin · 10 authors
This project explored coupling modeling and analysis methods from multiple domains to address complex hybrid (cyber and physical) attacks on mission critical infrastructure. Robust methods to integrate these complex systems are necessary to enable large trade-space exploration including dynamic and evolving cyber threats and mitigations. Reinforcement learning employing deep neural networks, as in the AlphaGo Zero solution, was used to identify "best" (or approximately optimal) resilience strategies for operation of a cyber/physical grid model. A prototype platform was developed and the machine learning (ML) algorithm was made to play itself in a game of 'Hurt the Grid'. This proof of concept shows that machine learning optimization can help us understand and control complex, multi-dimensional grid space. A simple, yet high-fidelity model proves that the data have spatial correlation which is necessary for any optimization or control. Our prototype analysis showed that the reinforcement learning successfully improved adversary and defender knowledge to manipulate the grid. When expanded to more representative models, this exact type of machine learning will inform grid operations and defense - supporting mitigation development to defend the grid from complex cyber attacks! This same research can be expanded to similar complex domains.
Open access
Smart Grid Security and Resilience
Distributed and Parallel Computing Systems
Infrastructure Resilience and Vulnerability Analysis
As CKD progresses, the capacity of the kidneys to eliminate metabolic waste is gradually lost, resulting in the retention of a host of compounds. Many of these solutes affect biologic functions and are likely contributing to the uremic syndrome, affecting not only morbidity and mortality but also patient-centered outcomes (fatigue, pruritus, sleep disorders) and quality of life (1). Our knowledge on the nature and action of the uremic compounds is still expandingâa progress at least partly attributable to the acquisitions of metabolomic analysis, which allows the blinded search for previously unknown molecules (2). The intensive exploration of the role of the intestine in the generation of uremic toxins was set in motion only during the past decade (3). The chain of events at play generally begins with dietary protein degradation followed by the metabolic transformation (fermentation) of amino acids by the gut microbiota and their conjugation (mostly sulfatation and glucuronidation) in the intestinal wall or liver by phase 1 and phase 2 metabolizing enzymes. Conjugation is, essentially, intended to increase solubility and neutralize toxicity, but the latter effect may remain incomplete, as several end-products still exert toxicity (4). In the search for intestinally generated uremic solutes, some proof-of-concept metabolomic studies identified a number of discriminators by comparing plasma or urine from either germfree rodents with control animals (5) or human subjects with and without a colon (6). Several identified molecules appeared to be known protein-bound uremic toxins, such as indoxyl sulfate, p-cresyl sulfate, and phenyl sulfate. In this issue of the Clinical Journal of the American Society of Nephrology, Mair et al., in their study on patients on dialysis with and without a colon, used a slightly different approach than in their previous study (6), resulting in a considerable extension of our knowledge on uremic solutes of intestinal origin (7). A sophisticated analytic platform comparing urine of patients with normal kidney function with or without colon yielded 91 colon-derived molecules. This selection was then narrowed by comparing the plasma of controls with that of patients on maintenance hemodialysis, resulting in a definite list of 60 intestinally generated uremic solutes. By using a chemical reference library, Mair et al. (7) could then define the structure of 34 of these substances, among which 22 were classified as newly detected intestinally generated retention products. Many (but not all) of these solutes were protein bound and/or sulfates, glucuronides (as demonstrated by sample sulfatase treatment), or metabolites of phenyl acetic acid. For the majority of compounds of which it was possible to calculate kidney clearance, this parameter exceeded creatinine clearance. As the latter can be considered a proxy of GFR, this suggests substantial active kidney tubular secretion, and may cast some doubts on the value of GFR as an all-inclusive measure of kidney function. The question is how this considerable extension of knowledge can be applied for the better to improve the quality and sustainability of the treatment and life quality of patients with kidney failure. One point is certain: the idea that the uremic syndrome is a simple condition, resulting from the activity of one or a few retention solutes, is further away than ever. It seems tempting to embark upon a large experimental effort to unravel the toxicity of the newly detected solutes, but such an endeavor should not be underestimated. Next to the identification of the solutes per se, the uremic concentration needs to be determined which necessitates the availability of the pure compound (either purchased or synthesized) before the biochemical impact can be tested, preferably in several appropriate organ or cell systems (4). Such approach may be extremely time-consuming unless well designed, high-throughput systems can be applied. The number of solutes to be tested could, however, be reduced on the basis of data from large sample collections and big data analysis, taking into consideration hard outcomes as well as patient-centered end points. In addition, systems biology could be used to unravel interactions among metabolites, the most important pathways involved and the most important metabolites. Another option could be the selection of solutes with the most outspoken characteristics, e.g., the largest concentration gap between normal and hemodialysis or between those with and without a colon, or those solutes with the highest tubular secretion. Perhaps more importantly, the reported data may help guiding the development of novel therapeutic procedures. As the study by Mair et al. detected large clusters with common characteristics (sulfates and glucuronides; phenols, cresols, and indoles), these could be approached by specific sorption methods aimed at capturing these structures. If such methods can be developed, they could also help to offer proof of concept regarding whether removing those solutes improves outcomes. Another option suggested by this study is correction of the intestinal dysbiosis by modifying intestinal bacterial metabolism, for which several proof-of-concept studies are already available, applying different diets, probiotics, prebiotics, synbiotics, or antibiotics (8). However, it might be dangerous to jump to conclusions. When Mair et al. considered the urinary excretion ratio of patients without a colon versus controls per individual molecule, it almost always exceeded zero (7), suggesting extraintestinal sources. Likewise, even if one does not account for the five patients with an ileal pouch, which appears to preserve some intestinal microbial activity, more than 20 intestinally generated uremic solutes were found in the urine of some patients and seven were found in all patients without a colon. Also for other reasons, targeting the colon as an isolated effort may offer an insufficient response to the uremic problem. A recent classification on the basis of preset criteria summing up 24 uremic solutes with the most important biochemical and clinical impact (9) contained only four of the solutes retrieved in the analysis of Mair et al. (7) (indoxyl sulfate, p-cresyl sulfate, trimethylamine-N-oxide, and indole acetic acid). This does not exclude yet unproven toxicity of some of the newly retrieved solutes by this study (7), but does suggest that a large number of solutes with toxic potential may not be entirely of intestinal origin. Of note, the aggregated results of the study by Mair et al. (7) also point to the role of an axis comprising the intestine, liver, plasma protein binding, and tubular excretion, rather than one of the intestine alone. All these observations might translate into difficulties to sufficiently reduce concentration of the concerned solutes by applying intestinal methods only. Tackling the intestine may be one of the solutions, but it is not the only solution. Subsequently, research efforts should be continued and strengthened to develop also other alternative ways to enhance toxin removal, such as decreasing protein binding, sorption, preservation of kidney function, increasing tubular secretion, and applying various acquisitions at the intersection of kidney replacement therapy and regenerative medicine (bioartificial kidney) or regenerative medicine per se (stem cells, organoids, bioengineered kidneys). Stimulating research in these areas is an important task for the nephrological community and all those involved in health policy, as patients, their families, and health professionals are in need of innovations in a field that has stagnated for too long and has too high amounts of health expenditures in its current form. In this context, targeting the intestinal microbiome remains a cheap and noninvasive therapeutic option, with a potential outreach to a large number of patients. In spite of the impressive efforts to accomplish this analysis and the vast amount of information offered, the study by Mair et al. (7) unavoidably raises some questions and concerns. Regardless of the comforting double-check of the reliability of the data provided for the most familiar uremic solutes, mass spectrometric analysis as used here remains semiquantitative, which may be a source of error, especially for calculated values such as clearances, ratios, or free fractions. Also, the use of spot urines sometimes necessitating drastic dilution is a potential source of error. Some seemingly obvious colon-derived candidate molecules, such as indoxyl glucuronide, hippuric acid, or phenyl acetic acid, that were traced by other metabolomic studies, sometimes by the same group (6), were absent in this analysis, which makes one suspect that either analytical bias or individual differences in nutritional status, metabolism, or genetics, may affect the findings. Other potentially skewing factors may be the overwhelming majority of patients with CKD and those on hemodialysis suffering from diabetes versus none in the control and colectomy groups, or the presence in the colectomy group of patients on immunosuppressive agents, as both may modify the intestinal microbiome (10,11). In conclusion, this study contains convincing but not entirely unexpected evidence that colonic generation of uremic toxins concerns even more molecules than previously demonstrated. GFR is, in many cases, not representative of kidney clearance. The study also supports the concept of molecule families and the existence of a gut/liver/plasma protein binding/kidney tubular axis, the disruption of which by one or more therapeutic measures could bring down the concentration of those solutes. Research in these areas should be able to modify the current paradigm of kidney treatment to make it more sustainable. This includes the exploration of previously underexploited areas such as manipulation of intestinal function, and alternative extracorporeal removal strategies such as adsorption and regenerative medicine. Disclosures R.V. has received travel support and speakers fees from Nikisho and BBraun, and is a consultant for Debiotech, the Dutch Kidney Foundation, and Astra-Zeneca. G.G. reports no conflict.
Raziel combines secure multi-party computation and proof-carrying code to provide privacy, correctness and verifiability guarantees for smart contracts on blockchains. Effectively solving DAO and Gyges attacks, this paper describes an implementation and presents examples to demonstrate its practical viability (e.g., private and verifiable crowdfundings and investment funds). Additionally, we show how to use Zero-Knowledge Proofs of Proofs (i.e., Proof-Carrying Code certificates) to prove the validity of smart contracts to third parties before their execution without revealing anything else. Finally, we show how miners could get rewarded for generating pre-processing data for secure multi-party computation.
Jeremy A. Scher, Michael G. Bayne, Amogh Srihari, Shikha Nangia · 5 authors
The relationship between structure and property is central to chemistry and enables the understanding of chemical phenomena and processes. Need for an efficient conformational sampling of chemical systems arises from the presence of solvents and the existence of non-zero temperatures. However, conformational sampling of structures to compute molecular quantum mechanical properties is computationally expensive because a large number of electronic structure calculations are required. In this work, the development and implementation of the effective stochastic potential (ESP) method is presented to perform efficient conformational sampling of molecules. The overarching goal of this work is to alleviate the computational bottleneck associated with performing a large number of electronic structure calculations required for conformational sampling. We introduce the concept of a deformation potential and demonstrate its existence by the proof-by-construction approach. A statistical description of the fluctuations in the deformation potential due to non-zero temperature was obtained using infinite-order moment expansion of the distribution. The formal mathematical definition of the ESP was derived using the functional minimization approach to match the infinite-order moment expansion for the deformation potential. Practical implementation of the ESP was obtained using the random-matrix theory method. The developed method was applied to two proof-of-concept calculations of the distribution of HOMO-LUMO gaps in water molecules and solvated CdSe clusters at 300 K. The need for large sample size to obtain statistically meaningful results was demonstrated by performing 105 ESP calculations. The results from these prototype calculations demonstrated the efficacy of the ESP method for performing efficient conformational sampling. We envision that the fundamental nature of this work will not only extend our knowledge of chemical systems at non-zero temperatures but also generate new insights for innovative technological applications.
Open access
Advanced Physical and Chemical Molecular Interactions
In order to solve the problem of illegal memberâs tracking attack, which caused by the vehicle unitsâ privacy disclosure in vehicular ad hoc networks (VANETs), a vehicle identity authentication protocol based on lightweight group signature was proposed by analysis of topology and communication characteristics of VANETs in this paper, which can authenticate the vehicles anonymously in a fast and efficient way. The protocol has five stages. In the initialization phase, the public/private key pairs and system parameters of the group were generated by the VANETs system, then the group public key and system parameters were distributed to the on-board units by the roadside auxiliary facilities. The group private key was kept by the group manager. When a vehicle unit entered VANETs, the unitâs own identity was submitted to the group manager by the blind signature. A group certificate would be distributed to the vehicle unit by the group manager when authentication passed. In the cooperative communication stage, the vehicle member who owned the group certificates signed the state information with the valid certificate and group public key, then sent it to the nearby vehicle units by the car sensors, and achieved cooperative driving with surrounding vehicles. In the message verification stage, only can the legal vehicle members open the received status information by using group public key, but couldnât know the true identity of the message sender. In this way, the anonymous communication among vehicles was realized. In the stage of signature verification, when a vehicle unit broadcasted a false message for the purpose of exclusively using road resource and caused traffic accident, the group manager can open the signature of the message by using the group private key, and traversed the corresponding vehicle members to carry on the accountability. The innovation of the paper was the usage of improved lightweight group signature technology, which could ensure that the length of group public key and group signature didnât depend on the number of group members. Zero knowledge proof was also used as a means of membership authentication which improved the speed of authentication among the members. The security of the protocol was analyzed and proved mathematically in this paper, and a LAN simulation platform composed of 100 PC machines was built to simulate the cooperative communication among vehicle units in VANETs. The experimental results showed that authentication time of the protocol was about 7 ms among 100 vehicle users. The performance of the proposed protocol is superior to the contrasted schemes. It greatly reduced the storage and calculation burden of the vehicle units during the process of identity authentication.
This paper describes the development of a multiagent system (MAS) to support the implementation of zero-defect manufacturing strategies in multi-stage production systems. The MAS infrastructure, combined with on-line inspection tools, data analytics and knowledge generation, constitutes a suitable approach to integrate process and quality control in multi-stage environments. This will allow the early detection of product defects, the adaptation to operating condition changes and the optimisation of manufacturing processes. This type of integrated management structure is aligned with a zero-defect manufacturing production model which is of paramount importance in the actual state-of-the-art manufacturing paradigms. As a proof of concept, the devised manufacturing supervision model was deployed into an experimental multi-stage system that run a set of several tests on electrical motors. The agent-based solution was implemented using the JADE framework and the exchange of information structured by proper data models and industrial based Internet-of-Things and Machine-to-Machine technologies, such as OPC-UA, REST and JSON. The obtained results demonstrate the suitability of the devised integrated management model as a vehicle to achieve dynamic and continuous system improvement in multi-stage manufacturing environments.