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181 results · page 6 of 8
流之介 永山, Ryunosuke Nagayama, 一幸 首藤, Kazuyuki Shudo
No abstract is available for this record.
Robert Šajina
Blockchain je u proteklih nekoliko godina dobio široku pozornost zbog njegove primjene na kripto valutama i tehnologijama distribuiranih knjiga (Distributed Ledger), kao što su Bitcoin i Ethereum. Složena i decentralizirana priroda blockchain tehnologija otežava razumijevanje ponašanja pojedinih komponenata i njihovog učinka na blockchain sustav. Dolaskom novih konsenzus algoritama, kao što je Proof of Authority (PoA), razumijevanje ovog složenog sustava postaje izazovan zadatak. U ovom radu predlažemo PoASim, podesiv, diskretni simulacijski alat za simulaciju dvaju glavnih PoA algoritama, nazvanih Clique i Aura. PoASim može pomoći korisnicima da bolje razumiju temeljne slojeve Ethereum blockchain-a, kao i razumijevanje razlika konsenzusa i nedostataka između dva konsenzus algoritma. PoASim tako može poslužiti kao koristan alat za bolje razumijevanje ponašanja svakog konsenzusa pokretanjem simulacija s različitim parametrima i analizom ponašanja sustava.
Pamela Hui Ting Chua, Yingjiu Li, Wei He
The EPCglobal Network is a computer network used to share product data between trading partners. The EPC Information Services (EPCIS) is an event record repository that allows disparate applications to access and query for data both within and across enterprises. Ultimately, this data sharing is aimed at enabling participants in the EPCglobal Network to gain a shared view of the disposition of EPC-bearing objects within a relevant business context [1].Despite the potential benefits, enterprises are reluctant to integrate into the EPCglobal Network due to the financial and manpower resources required to set up, operate and maintain the EPCIS and to adopt the standards. Issues like security, computation and storage overheads would also have to be managed. To solve the problem, this paper advocates a blockchain solution using Hyperledger Fabric to serve as a shared EPCIS across trading partners. The blockchain can be queried directly to facilitate information sharing subjected to access control rules. It also adheres to the EPCglobal Network standards. This approach provides several important benefits including eliminating the need for enterprises to maintain their own EPCIS while still being able to participate and benefit from the network. As the blockchain can be queried directly, the provision of EPC Discovery Services (EPCDS) may also be unnecessary. To explore this idea, we constructed a prototype using Hyperledger Composer and Hyperledger Fabric while adhering to the data elements, structures and formats as stated in the standards to ensure interoperability with existing architecture both upstream and downstream.
娜 田
No abstract is available for this record.
Sein Myung, Jong-Hyouk Lee
신뢰하는 중앙기관 없이 노드간 합의를 통해 신뢰성 있는 데이터 공유를 지원하는 블록체인은 비트코인을 시작으로 다양한 분야에서 활용되고 있다. 다양한 블록체인 플랫폼 중 스마트 컨트랙트를 지원하는 이더리움은 다양한 블록체인 서비스 구축에 활발히 활용되고 있지만 아직까지 이더리움 네트워크의 동작 방식이나 특징을 분석한 연구는 미비하다. 본 논문에서는 이더리움 네트워크 구성시 반드시 필요한 노드 탐색 과정을 분석한다. 이더리움 네트워크의 특징과 주요 프로토콜 및 노드 탐색 과정을 설명하고, Go언어로 작성된 이더리움 구현물인 geth의 네트워크 동작에 따른 함수 콜 그래프 분석 결과를 제공한다.
Jong-Ki Lee, Hwa-Yeol Choi
4차산업혁명 시대는 새로운 도전을 하게 만들었으며, 특히 블록체인 기술은 많은 혁신 기술의 발전을 견인하고, 이제는 블록체인 생태계를 구축하여 많은 사용 사례를 창출하고 일반화되어 가는 기술로 볼 수 있다. 이러한 블록체인 기술을 처리하기 위한 도커 컨테이너(Docker Container) 사용 확산 추세에 발맞추어, 본 연구에서는 도커 컨테이너에 기초한 오픈 소스 하이퍼레저 컴포즈(Hyperledger Composer) 비즈니스 네트워크 구현을 실행하였다. 도커 컨테이너의 환경설정, 커밋 그리고 웹 브라우저를 통한 블록체인 사용 절차를 살펴보고 실제적인 비즈니스 모델을 구현하였다. 본 연구는 도커 컨테이너의 이해, 블록체인 하이퍼레저 컴포저 참여자 및 거래 처리 방법을 구현하고, 실제로 비즈니스 네트워크 블록을 만들어 실행하였다. 이를 통하여 오픈 소스 하이퍼레저 컴포저 블록체인 기술의 근간을 이해하고, 하이퍼레저 컴포즈 블록체인 기술의 사용 확산과 여러 비즈니스 환경에서의 응용에 기여하고자 한다.The era of the fourth industrial revolution has created a new challenge. In particular, the block chain technology has led to the development of many innovative technologies, and now it can be seen as a technology that creates many use cases and becomes generalized by building a block chain ecosystem. In keep ing with the trend of using Docker Containers to handle these block chain technologies, we have implemented an open source Hyperledger Composer business network based on a Container of Docker. We set up an actual business model by examining the configuration of the container, the commit, and the block chain using the web browser. Based on the understanding of the Docker Container, this study materialized the block chain Hyperledger Composer participant and transaction processing method, and eventually created and executed the business network block. Through this, we will be able to understand the fundamentals of open source Hyperledger Composer block chain technology and will ultimately contribute to the spread of use of Hyperledger Composer block chain technology and its application in various business environments.
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.
Cristian PĂUNA
When dot.com has become a quaint idea, when electronic shops have lost the mass attention, while classical and margin trading has become obsolete, something new is coming: cryptocurrencies. Hundreds of virtual coins have been invented for a single reason: the profit. The high price volatility of these new markets and the fact that the virtual coins price is not regulated by a central bank or a single exchange, gives us opportunities for arbitrage trading. The existence of important price differences makes possible the profit when an automated system buy cheaper and sell more expensive in the same time. This paper will present the general principles underpinning the implementation of arbitrage trading software for virtual coins market. The very large number of cryptocurrencies and exchanges fundamentally change the server architecture of the trading software. The distributed price data in hundreds of sources and the technical differences of each of these data providers make all the things difficult to be implemented in a single application. The low-latency order calculation needed for the fast delivery before a significant price change, in the presence of thousands of price quotes coming from hundreds of distributed servers makes everything special.
Jong-Ki Lee
4차산업혁명시대에 블록체인기술이 각광 받고 있다
Debajani Mohanty
You know what the Ethereum architecture looks like, and you have practiced enough basic Solidity programming. Now it’s time to learn some advanced topics such as how to interact with services outside the blockchain by invoking calls through Oraclize, how to optimize gas usage by saving data to IPFS storage, and how to adopt best practices to write production-ready code in Solidity.
Debajani Mohanty
So far we have discussed the Ethereum architecture, Solidity programming, and the Ethereum client, including setting it up and compiling, running, and debugging Dapps. That’s a lot of work, isn’t it? In this chapter, let’s discuss two leading frameworks, Truffle and Embark, that will provide a set of tools and boilerplate code for scaffolding Dapps for Ethereum. The frameworks will do much of the work themselves and leave you with only a few tasks.
Riccardo Sibani
The recent emergence of a distributed technology named blockchain, clearly created a new point of view in the data storing and data distribution fields. If on one hand blockchain is mainly known for Bitcoin (an auto-regulated decentralized digital currency), on the other hand it has the potential to set up an auto regulated economy.In this thesis, the blockchain technology will be analyzed and described starting from P2P architecture and its origin in 2009 Satoshi Nakamoto’s whitepaper, and leading to the most up to date blockchains. The advantages and disadvantages of such architecture will be pointed out keeping in mind the security, speed and cost of such infrastructure.While Real Estate companies have often anticipated the technological innovations, land registries, instead, derive and keep a working manner which is extremely old and out of date: made of unclear procedures and wet signatures. The market needs and legislation will be researched mainly referring to other works and integrated with a technical point of view with particular focus on the decentralization of such systems.After analyzing the flow, problems and flaws of the current system, a new proposal will be researched, in particular trying to minimize the dead time in between the different steps of the mortgage, increase transparency, as well as reducing dependence on the central authorities, leading to more convenient interactions among the properties’ stakeholders. An attractive low capitalization decentralized financial product will also be proposed and implemented able to lower the interest rate and create a profitable investment with low risk, low interest and durable in time.Secure and ad-hoc algorithms will be presented and, in a later section, analyzed in combination with different blockchain technologies. Scalability and performance will also be evaluated, taking into account all the current technology limitations and the near future opportunities.
Alexander Chepurnoy, Vasily Kharin, Dmitry Meshkov
No abstract is available for this record.
Mohammed Ennahbaoui, Hind Idrissi
No abstract is available for this record.
Josef Gattermayer, Pavel Tvrdı́k
Peer-to-peer (P2P) design offers many benefits over a single-master or a multi-master architecture in terms of scalability, reliability and independence. The Clondike project is being converted from a grid computing system into a universal non-dedicated P2P cluster where every participating node can benefit from its membership in the cluster. But different design requires different types of algorithms in order to guarantee the same functionality. One of the challenges in P2P design is a fair scheduling and a general protection of the whole cluster against abusive or malfunctioning nodes. Algorithms used in a single-master or multi-master clusters do not work anymore. We have designed a multi-level system based on one of the main principles of cryptocurrencies to achieve a distributed master-less reputation rating across the cluster. This paper discusses proposed cluster multi-level reputation system and its parameters. The system is evaluated on a Clondike cluster on an experimental measurement with abusive nodes involved.
Daniel Drescher
The last step turned the blockchain data structure into an immutable, append-only data store that can serve as a tamper-resistant ledger for transaction data. Having a single, immutable, append-only history of transaction data in isolation may be of limited value for our goal of clarifying ownership based on a group of computers that serve as witnesses to ownership-related events. Hence, this step focuses on establishing a purely distributed peer-to-peer system that shares transaction information.
Merla Kubli
Renewable energies, especially photovoltaic (PV), have started a trend towards a decentralization of energy systems. With decreasing levelized costs of energy of new renewable energies, self-consumption concepts become increasingly attractive and have even reached grid parity in some countries already. So called "prosumers" (households that are producers and consumers at the same time) start to replace grid consumers, conducting self-consumption with their locally produced electricity by the PV plants. Since complete autarky cannot be reached with a PV plant for a household, prosumers still consume electricity from the main grid. This on-going diffusion of self-consumption concepts is significantly influenced by the interplay of network externalities within the system, such as learning from peers, altering the perceived utility by households of the investment into decentral generation. The increasing penetration of PV significantly contributes to the creation of a more sustainable power supply in Europe and is considered and supported in many nations by governmental energy strategies. Nevertheless, such decentralization dynamics also lead to multiple challenges in the energy system. New investors enter the energy market, utility companies are forced to adjust their business models and grid operators face technical as well as financial challenges. The presented paper focusses on the financial challenges of grid operators caused by decentralization trends of the electricity system.
Mateusz Guzek, Xavier Besseron, Sébastien Varrette, Grégoire Danoy · 5 authors
The growing parallelism and heterogeneity of modern computing infrastructures such as High Performance Computing (HPC) platforms raises new challenges to their programmers and users. Additional requirements have emerged nowadays, such as minimizing the consumed energy, reducing the utilized system resources, or providing built-in reliability mechanisms. Therefore High Performance Computing (HPC) applications require adaptation mechanisms and then must avoid traditional monolithic centralized approaches in favor of novel autonomous, flexible and decentralized decision systems. In this context, we describe here a dynamic and flexible adaptation scheme based on a Multi-Agent System (MAS) to handle parallel or distributed executions in an HPC environment. More precisely, we model and extend the existing HPC middleware Kaapi to offer the power of the ParaMoise multi-agent organizational framework. Our proposed solution, named ParaMASK, relies on the similarities between ParaMoise workflow-based functional specifications and the Direct Acyclic Graph (DAG) representation of the distributed execution within Kaapi. As a result, ParaMASK permits to analyze and reorganize the scheduling of tasks that compose a program in an autonomous and decentralized way, while additionally handling dynamic adaptations (using task migration to fulfill energy consumption goals for example). The proposed solution was implemented on top of the existing Kaapi middleware and includes an optimized algorithm for the agent coordination. ParaMASK has been validated with a series of experiments on a real computational grid. Experimental results show a good scalability and an exceptional low overhead induced by the approach: less than 1.5% execution time increase with periodic coordinations every 15 seconds on 2662 cores.
Enas Al Kawasmi, Edin Arnautović, Davor Svetinović
ABSTRACT This paper presents a system‐of‐systems architecture model for a Decentralized Carbon Emissions Trading Infrastructure (D‐CETI) with focus on privacy and system security goals. The structure and behavior are implemented as a solution to the problem of trading carbon emissions anonymously among the trading agents. Privacy and security of the trading agents and their carbon credits are the main requirements behind the architecture of D‐CETI. The decentralized structure of multiple systems and distributed behavior are the two main features of D‐CETI that distinguish it from the traditional carbon trading schemes and protocols. D‐CETI is based on Bitcoin, a peer‐to‐peer digital currency with no central authority, and Open Transactions, a system that simplifies the use of cryptography in financial transactions. The architecture of D‐CETI is evaluated and compared with the architecture of five other carbon emissions trading platforms.
Michael Sonnenschein, Ontje Lünsdorf, Jörg Bremer, Martin Tröschel
No abstract is available for this record.
Xiang Zhao, Guangyu Hu, Zhigong Wu
Smart grid is the intelligent power grid, in which Scheduling system is the most important part. In this paper, we will introduce a new schedule system based on contract net protocol improved scheduling efficiency. As one of the most important coordination mechanism, contract net protocol (CNP) has been extensively studied in many areas, and many other techniques can also be used to improve the quality of decision. The new CNP is based on trust mechanism, that makes the system more efficient scheduling. Experimental results show that the initiators with trust model almost steadily get the best participants no matter the environment is honest-dominated or dishonest-dominated. Even in the dishonest-dominated environment, this approach gets better results and is proved valuable.
Paul L. Snyder, Giuseppe Valetto
Describing, understanding, and modeling the emergent behavior of self-organizing software systems remains an open challenge. Such systems can solve problems in computing domains where traditional, centralized models are impractical or problematic, including ubiquitous and pervasive computing, peer-to-peer networks, large-scale grids, and Ultra-Large-Scale Systems. Self-organizing approaches have demonstrated great promise in building adaptive behavior into decentralized systems, enabling cooperative, autonomous self-management and the exploitation of the heterogeneity of system components. My investigation of self-organizing software systems has revolved around Myconet, an unstructured overlay protocol for peer-to-peer networks. Myconet takes inspiration from fungal growth patterns in order to build an efficient self-optimizing superpeer topology that can also rapidly self-heal in response to damage orattacks. Myconet has proven to be flexible, and has been used as a platform for the development of other self-organizing applications in large-scale distributed systems, including load-balancing in distributed service networks (Mycoload), and detection and mitigation of attacks against the overlay (Hormone-Inspired Topology Adaptation Protection [HITAP] and Self-Organized Degree Adaptation Protection [SODAP]). Each extension has given additional insights into the self-organizing dynamics of such systems, but has also shown the limitations of ad hoc approaches to the design and analysis of new applications. These experiences have led me to investigate formal tools and models that may provide the designer of a self-organizing system with early and accurate insight through augmented analytical power. This research selects a small set of synergistic modeling techniques, and builds an integrated approach to modeling for the design and validation of self-organizing software systems. These tools are used to model the core Myconet platform and its currently developed extensions, particularly focusing on the SODAP layer which provides self-protection features to a superpeer-based P2P overlay network. Once established, this modeling approach can be applied to the principled design of further Myconet extensions, as well as other self-organizing systems, thus advancing the understanding of how to model and engineer self-organization in software systems.
Raafat Aburukba, Hamada Ghenniwa, Weiming Shen
In the Grid computing environment, computation, services, and storage belong to different organizations or individuals with different objectives. Entities in this domain are autonomous and self-interested; however, they are willingly to share their resources to achieve their individual and collective goals. In such open environment, the scheduling decision is a challenge given the decentralized nature of the environment. Each entity has specific requirements that need to achieve. This work analysis the environment structure for the Grid, proposes a bidding language that is expressive and a winner determination algorithm that is adequate for the Grid computing environment.
Amar Bahadur Patel
Grid computing is the computing paradigm that is concerned with coordinated resource sharing and problem solving in dynamic, autonomous multi-institutional virtual organizations. Data exchange and service allocation between virtual organizations are challenging problems in the field of Grid computing, due to the decentralization of Grid systems. The resource management in a Grid system ensures efficiency and usability. The required efficiency and usability of Grid systems can be achieved by building a decentralized multi-virtual Grid system. In this thesis we present a decentralized multi-virtual resource management framework in which the system is divided into virtual organizations, each controlled by a broker. An overlay network of brokers is responsible for global resource management and managing the allocation of services. We address two main issues for both local and global resource management: 1) decentralized allocation of tasks to suitable nodes to achieve both local and global load balancing; and 2) handling of both regular and broker failures. Experimental results verify that the system achieves dependable performance with various loads of services and broker failures.