Blockchain technology has been recommended for the sustainability in the manufacturing industry, owing to its benefits in terms of real-time transparency and cost savings. To verify this, we first examine how firms can employ distributed ledger technology by adopting blockchain technology to achieve real-time transparency and cost savings. We also review the current blockchain technology applications in the financial industry and supply chains to explain this technology’s mechanisms for enabling real-time transparency and cost savings in the manufacturing industry. Finally, we theoretically compare the profits of manufacturing firms in two managerial delegation games under a duopoly situation. This theoretical model suggests that the real-time transparency and cost savings secured by blockchain technology improve the profitability and competitiveness of manufacturing firms, which, in turn, assure the sustainability in the manufacturing industry.
This paper examines the day of the week effect in the cryptocurrency market using a variety of statistical techniques (average analysis, Student's t-test, ANOVA, the Kruskal–Wallis test, and regression analysis with dummy variables) as well as a trading simulation approach. Most crypto currencies (LiteCoin, Ripple, Dash) are found not to exhibit this anomaly. The only exception is BitCoin, for which returns on Mondays are significantly higher than those on the other days of the week. In this case the trading simulation analysis shows that there exist exploitable profit opportunities; however, most of these results are not significantly different from the random ones and therefore cannot be seen as conclusive evidence against market efficiency.
Cryptocurrencies are being widely adopted to perform various online-based transactions; therefore, they are required to maintain a consensus to ensure a secured transaction. Blockchain comprises a distributed ledger, which holds digital records of individual crypto-transactions. Besides recording a particular activity, blockchain also ensures that the contents of the ledger are decided based on agreements of distinct participants. Various consensus mechanisms are followed by blockchain to ensure blocks are being summed up representing legitimate data on the network. However, the major consensus protocols comprise various limitations; and these are prone to different types of cyber attacks, such as Distributed denial-of-service, 51% attack, Double-spending, Long-range attack. In this paper, we analyze several attack vectors that can cause serious security threats due to the loopholes in the consensus mechanism. Our study involves examining 3 significant consensus mechanisms, which are followed by major cryptocurrencies. We also discuss the limitations of individual consensus mechanisms and demonstrate their robustness towards various attack vectors. We conclude that, although blockchain comprises proper consensus mechanisms to enhance secured crypto-transaction, unfortunately, it is not strong enough to defend against some cryptocurrency attacks which could discourage some users to adopt this technology.
Yonggen Gu, Dingding Hou, Xiaohong Wu, Jie Tao · 5 authors
Distributed data storage has received more attention due to its advantages in reliability, availability and scalability, and it brings both opportunities and challenges for distributed data storage transaction. The traditional transaction system of storage resources, which generally runs in a centralized mode, results in high cost, vendor lock-in and single point failure risk. To overcome the above shortcomings, considering the storage policy with erasure coding, in this paper we propose a decentralized transaction method for cloud storage based on a smart contract, which takes into account the resource cost for distributed data storage. First, to guarantee the availability and decrease the storing cost, a reverse Vickrey-Clarke-Groves (VCG) based auction mechanism is proposed for storage resource selection and transaction. Then we deploy and implement the proposed mechanism by designing a corresponding smart contract. Especially, we address the problem of how to implement a VCG-like mechanism in a blockchain environment. Based on the private chain of Ethereum, we make the simulation for the proposed storage transaction method. The results of simulation show that the proposed transaction model can realize competitive trading of storage resources and ensure the safe and economic operation of resource trading.
Zhengwei Ni, Wenbo Wang, Dong In Kim, Ping Wang · 5 authors
With the development of decentralized consensus protocols, permissionless blockchains have been envisioned as a promising enabler for the general-purpose transaction-driven, autonomous systems. However, most of the prevalent blockchain networks are built upon the consensus protocols under the crypto-puzzle framework known as proof-of-work. Such protocols face the inherent problem of transaction-processing bottleneck, as the networks achieve the decentralized consensus for transaction confirmation at the cost of very high latency. In this paper, we study the problem of consensus formation in a system of multiple throughput-scalable blockchains with sharded consensus. Specifically, the protocol design of sharded consensus not only enables parallelizing the process of transaction validation with sub-groups of processors, but also introduces the Byzantine consensus protocols for accelerating the consensus processes. By allowing different blockchains to impose different levels of processing fees and to have different transaction-generating rate, we aim to simulate the multi-service provision eco-systems based on blockchains in real world. We focus on the dynamics of blockchain-selection in the condition of a large population of consensus processors. Hence, we model the evolution of blockchain selection by the individual processors as an evolutionary game. Both the theoretical and the numerical analysis are provided regarding the evolutionary equilibria and the stability of the processors' strategies in a general case.
Permissionless blockchain systems, such as Bitcoin, rely on users using their computational power to solve a puzzle in order to achieve a consensus. To incentivise users in maintaining the system, newly minted coins are assigned to the user who solves this puzzle. A hardware race that has hence ensued among the users, has had a detrimental impact on the environment, with enormous energy consumption and increased global carbon footprint. On the other hand, proof of stake systems incentivise coin hoarding as players maximise their utility by holding their stakes. As a result, existing cryptocurrencies do not mimic the day-to-day usability of a fiat currency, but are rather regarded as cryptoassets or investment vectors. In this work we initiate the study of minting mechanisms in cryptocurrencies as a primitive on its own right, and as a solution to prevent coin hoarding we propose a novel minting mechanism based on waiting-time first-price auctions. Our main technical tool is a protocol to run an auction over any blockchain. Moreover, our protocol is the first to securely implement an auction without requiring a semi-trusted party, i.e., where every miner in the network is a potential bidder. Our approach is generically applicable and we show that it is incentive-compatible with the underlying blockchain, i.e., the best strategy for a player is to behave honestly. Our proof-of-concept implementation shows that our system is efficient and scales to tens of thousands of bidders.
In 2008, Satoshi Nakamoto proposed an electronic cash system (bitcoin) that is completely realized by peer-to-peer technology. The core value of this scheme is that it proposes a solution based on Proof-of Work, so that the cash system can run in a peer-to-peer environment and be able to prevent double-spend attacks. Bitcoin has been developed for ten years, and since then countless digital currencies have been created. But the discussion of double-spend attacks seems to still concentrate on 51% Attacks. In fact, our research has found that there are many other way to achieve double-spend attacks. In this paper, by introducing a number of double-spend attack vulnerabilities that we have found in EOS, NEO and other large blockchain platforms, we summarized various reasons for causing double-spend attacks, and propose an efficient mitigation measure against them.
Wesley Joon-Wie Tann, Xing Han, Sourav Sen Gupta, Yew-Soon Ong
Symbolic analysis of security exploits in smart contracts has demonstrated to be valuable for analyzing predefined vulnerability properties. While some symbolic tools perform complex analysis steps, they require a predetermined invocation depth to search vulnerable execution paths, and the search time increases with depth. The number of contracts on blockchains like Ethereum has increased 176 fold since December 2015. If these symbolic tools fail to analyze the increasingly large number of contracts in time, entire classes of exploits could cause irrevocable damage. In this paper, we aim to have safer smart contracts against emerging threats. We propose the approach of sequential learning of smart contract weaknesses using machine learning---long-short term memory (LSTM)---that allows us to be able to detect new attack trends relatively quickly, leading to safer smart contracts. Our experimental studies on 620,000 smart contracts prove that our model can easily scale to analyze a massive amount of contracts; that is, the LSTM maintains near constant analysis time as contracts increase in complexity. In addition, our approach achieves $99\%$ test accuracy and correctly analyzes contracts that were false positive (FP) errors made by a symbolic tool.
This essay examines in detail the properties of a well functioning monetary system - defined as money plus the mechanisms to execute payments - in both the short and long run, drawing on both theory and the lessons from history. It stresses the importance of trust and of the institutions needed to secure it. Ensuring price and financial stability is critical to nurturing and maintaining that trust. In the process, the essay addresses several related questions, such as the relationship between money and debt, the viability of cryptocurrencies as money, money neutrality, and the nexus between monetary and financial stability. While the present monetary system, with central banks and a prudential apparatus at its core, can and must be improved, it still provides the best basis to build on.
Yury Yanovich, Igor Shiyanov, Timur Myaldzin, Ivan Prokhorov · 6 authors
Counterfeit and unaccounted postage stamps used on mailings cost postal administrations a significant amount of money each year. Corporate and individual clients become victim to stamp fraud and incur losses when security teams investigate such mailings. The blockchain technology is supposed to be a solution to make postage stamps market transparent and to guarantee invariability of stamps volume produced and used. The blockchain-based supply chain for postage stamps is introduced in the article.
Being in this digital era, technology continuously updates with new variants in providing security while performing the financial transactions. It is a mandated task for the user for conducting secure transactions in order to defend the intruders to restrict the interference. This paper deals with digital currency-Cryptocurrency, that provides a medium of secure exchange between the peers during financial management. Authors explored the internal scheme of bitcoin and the abstract view of cryptocurrency to know how the bitcoin is providing a shield during financial negotiation between peers with various application in security point of view.
We study an unsteady nonlinear fluid–structure interaction problem. We consider a Newtonian incompressible two-dimensional flow described by the Navier–Stokes 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 fluid–structure 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
Revisões sistemática da literatura está se tornando cada vez mais comum nas mais variadas áreas de estudo. Este trabalho apresenta uma revisão sistemática da utilização da tecnologia Blockchain com Smart Contracts aplicado para a área de logística. A pesquisa foi baseada na execução de consultas através de strings de busca específicas em duas bases de conhecimentos renomadas na área científica. Verificou-se que, apesar da existência de um número considerado de artigos sobre o tema, especificamente a aplicação da tecnologia de Blockchain com Smart Contracts voltados para a área de logística ainda se apresenta com uma nova competência de estudos e aplicações empresariais. A pesquisa é baseada em buscas através de Strings mapeando especificamente a aplicação da tecnologia de Smart Contracts aplicados a logística. Verificou-se que apesar dos artigos encontrados abordarem o mesmo tema, há um grande número de propostas para a aplicação da tecnologia e um número pequeno de artigos quando se trata de artigos focando exclusivamente a aplicação da tecnologia. A partir dos resultados apresentados pode-se concluir que, as aplicações de Smart Contracts voltados para a área logística é um campo fértil para o desenvolvimento de inúmeras aplicações para as empresas e de pesquisas acadêmicas.
The majority of rural Indian households remain dependent on traditional, inefficient and harmful household energy technologies. Rural households make their energy decisions with respect to the Water-Energy-Food security (WEF) Nexus jointly, however, previous research initiatives have analyzed household energy access problem in isolation. Taking this WEF nexus into account, this thesis investigates factors influencing household energy transition and identifies an optimal village energy system (VES) for the rural communities in Uttar Pradesh, India. The thesis also analyzes the distributional impacts of VES on different categories of rural households.<br /> Using detailed household survey data, Logit and Zoib (zero one inflated beta) regression techniques were applied to analyze household's activities and to identify factors influencing household energy transition. The results showed that regular non-agricultural income of household's male member increases the probability of household's modern cooking energy and modern lighting transition by 8.6% and 13.6%, respectively. It was found that household's higher agricultural dependence and resource endowments (more labor and cattle) lead to higher share of traditional bioenergy consumption in the total cooking energy mix. Proximity to markets and high household income were observed to positively influence household modern cooking and lighting transition. Local institutions such as local bio-energy markets and barter trade for labor- bioenergy were observed to have significant influence on household energy choice. Results also showed that government's policy instrument such as household connection to government LPG scheme is associated with 20.5% increased probability of household using modern cooking energy as its primary cooking fuel. Results also indicated that social factors such as higher female education and young age of household head are associated with household's increased modern cooking energy consumption in its total cooking energy mix.<br /> The thesis utilized linear optimization technique to formulate a village energy model in GAMS (General Algebraic Modeling Software). The model identified an optimal Village Energy System (VES) considering all possible energy sources and technologies (energy systems) as well as their linkages with food security. Results confirmed energy systems interdependencies for the rural communities. For instance, results showed that the levelized cost of electricity generation from biomass gasifier power system is 2.54 INR/ MJ as compared to 2.89 INR/ MJ from grid electricity-battery based power system. However, model selected the latter for fulfilling village's night time power needs while it assigned higher shadow price of 0.143 INR / MJ to the former. This happened because possible utilization of gasifier power system was expected to create scarcities of local bio-energy resources, resulting in costlier cooking energy system for the village. It was found that DES (Decentralized Energy System) provides demand side energy management opportunities with different energy prices at different timings of the day. Results also showed that high cost of finance deters possible adoption of renewable power technologies, such as solar power.<br /> Lastly, the thesis constructed an agricultural household model linked with VES to analyze VES's welfare consequences on rich and poor households. Here, household had the opportunity to purchase VES's energy services and sell its bio-energy feedstocks to VES. For the poor household, this interaction with VES led to its increased agricultural production with around 22% increase in its farm area cultivation in summers, as well as led to reduction in its off-farm labor by around 11% which is then utilized in its own agriculture. Overall, this interaction resulted in around 4% increase in poor household's annual income. On the down side, this interaction led to poor household shifting towards dirtier cooking energy technologies, resulting in increased external costs and CO2 emissions by around 27% and 45%, respectively. On the other hand, VES did not impact rich household's food production and only marginally increased its economic gain. However, it led to rich household shifting towards cleaner cooking energy thereby resulting in reduction of its external costs almost by half.
Recently, Halal food has drawn remarkable attention of many consumers around the world. Besides to being unsafe, Halal food such as meat can encounter several issues throughout its supply chain and logistics. At any time, Halal integrity is not guaranteed and risks of becoming non-Halal is the major concern of all parties along the supply chain. To respond to Muslim consumers’ trust concerns in Halal food, many traceability systems were proposed in previous studies based on emerging technologies and recommended to be incorporated into Halal food supply chains. Nevertheless, all of these systems are centralized, opaque and not enough transparent. To mitigate these problems, blockchain technology is introduced as a ground-breaking innovation with greater decentralization, visibility and transparency. This paper makes a major contribution in suggesting Halal meat supply chain traceability system for real-time food tracing based on embedding Islamic dietary law into HACCP, blockchain and Internet of Things.
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.
Diabetes Mellitus, usually called only Diabetes, is a worldwide chronic metabolic disorder that is characterized by abnormal oscillations in blood sugar levels. Such levels should be monitored by diabetes patients, which traditionally have had to take blood samples by finger-pricking, at least between twice and four times a day. Finger-pricking has a number of drawbacks that can be tackled by Continuous Glucose Monitors (CGMs), which are able to determine blood sugar levels throughout the day and not only at specific time instants. In this paper, the design of an IoT CGM-based system is proposed, whose collected blood sugar sample values can be accessed remotely; thus being able to monitor patients, specifically dependent ones (e.g., children, elders, and pregnant women) and warn them in the case where a dangerous situation is detected. In order to create such a system, a fog computing system, based on distributed mobile smart phones, has been devised to collect data from the CGMs. Moreover, the use of a blockchain is proposed, to receive, validate, and store the collected data with the objective of avoiding untrusted sources and, thus, to provide a transparent and trustworthy data source of a population, which can vary in age, ethnicity, psychology, education, self-care, and/or geographic location, in a rapid, flexible, scalable, and low-cost way. These crowdsourced data can enable novel mHealth applications for diagnosis, patient monitoring, or even public health actions, which can help to advance in the control of the disease and raise global awareness on the increasing prevalence of diabetes.
Tiago M. Fernández‐Caramés, Óscar Blanco-Novoa, Manuel Suárez-Albela, Paula Fraga‐Lamas
Industry 4.0 has paved the way for a world where smart factories will automate and upgrade many processes through the use of some of the latest emerging technologies. One such technology is Unmanned Aerial Vehicles (UAVs), which have evolved a great deal in the last several years in terms of technology (e.g., control units, sensors, UAV frames) and have reduced significantly their cost. UAVs can help industry in automatable and tedious tasks, like the ones performed on a regular basis for determining the inventory and for preserving the traceability of certain items. Moreover, in such tasks, it is essential to determine whether the collected information is valid or true, especially when it comes from untrusted third-parties. In such a case, blockchain, another Industry 4.0 technology that has become very popular in other fields like finance, has the potential to provide a higher level of transparency, security, trust and efficiency in the supply chain and enable the use of smart contracts. Thus, in this paper, the design and preliminary results are presented of a UAV-based system aimed at automating the inventory and keeping the traceability of industrial items attached to Radio-Frequency IDentification (RFID) tags. Such a system can use a blockchain to receive the inventory data collected by UAVs, validate them, ensure their trustworthiness and make them available to the interested parties.
Almost a decade on from the launch of Bitcoin, cryptocurrencies continue to generate headlines and intense debate. What started as an underground experiment by a rag tag group of programmers armed with a Libertarian manifesto has now resulted in a thriving $230 billion ecosystem, with constant on-going innovation. Scholars and researchers alike are realizing that cryptocurrencies are far more than mere technical innovation; they represent a distinct and revolutionary new economic paradigm tending towards decentralization. Unfortunately, this bold new universe is little explored from the perspective of Islamic economics and finance. Our work aims to address these deficiencies. Our paper makes the following distinct contributions We significantly expand the discussion on whether cryptocurrencies qualify as "money" from an Islamic perspective and we argue that this debate necessitates rethinking certain fundamental definitions. We conclude that the cryptocurrency phenomenon, with its radical new capabilities, may hold considerable opportunity which merits deeper investigation.
Blockchain systems and smart contracts provide ways to securely implement multi-party transactions without the use of trusted intermediaries, which currently underpin many commercial transactions. However, they do so by transferring trust to computer systems, raising the question of whether code can be trusted. Experience with high value losses resulting from incorrect code has already shown that formal verification of smart contracts is likely to be beneficial. This note investigates the specification and verification of a simple form of multi-party transaction, atomic swaps. It is argued that logics with the ability to express properties of strategies of players in a multi-agent setting are conceptually useful for this purpose, although ultimately, for our specific examples, the less expressive setting of temporal logic suffices for verification of concrete implementations. This is illustrated through a number of examples of the use of a model checker to verify atomic swap smart contracts in on-chain and cross-chain settings.
The choice of the consensus method ultimately determines throughput, scalability, tamper resistance, and consistency of a blockchain system. However, across all the types of blockchain (private, semi-private, consortium, or public), there is no consensus method that uniformly addresses all these traits. Verifiable lottery algorithms (Proof of ...) increase tamper resistance but show weakness in throughput and scalability, while established methods like PAXOS and RAFT provide no additional protection against tampering. In this paper, we introduce Right to Sign which aims to provide additional tamper resistance by cryptographic signatures over a broad range of available consensus finding methods.
The purpose of this study is to investigate the factors impacting the student satisfaction with the public and private universities of Malaysia and Pakistan, which are countries representing South/South-East Asia in cross-culture perspective.The study has applied a quantitative survey design guided by five hypotheses.A questionnaire was distributed among the students of private and public universities.A conceptual framework has been developed based on the modification of Student Satisfaction Index (SSI) model to measure the satisfaction of students from different aspects, such as university image, university location, quality of academic staff, university facilities, student expectation, overall student satisfaction.The research method used was a survey-based questionnaire that consisted of a total of 396 responses from the university students.The data were analyzed with SPSS and SmartPLS 3; the results indicate that when the comparison was made separately between private and public universities of Malaysia and Pakistan.The comparative statistical score was obtained using independent sample t-Test, the university facilities of Malaysian universities resulted higher than universities in Pakistan.Therefore, the independent sample ttest results conclude that the university facilities have a significant evidence (p=0.00) to support our research findings that university facilities do affect the student satisfaction more in Malaysia (mean=4.1788)than Pakistan (mean =3.7212) and the research hypothesis is significant that there is a significant difference in student satisfaction towards university facilities in Malaysia and Pakistan.Similarly, the quality of academic staff (p=0.035) has a significant effect on student satisfaction in Malaysia (mean=3.8283) and Pakistan (mean=3.6641).Furthermore, this leads the student expectation and overall student satisfaction level of Malaysia students are higher than students in Pakistan.However, student satisfaction level on university image and university location in Malaysia and Pakistan do not differ.The study is useful for university management to improve university students satisfaction.The future researchers are recommended further explore demographic and cultural variables impact on student satisfaction.