Christoph H.-J. Braun, Janina Traue, Boris Lingl, Tobias Käfer
We present an approach for documenting the execution of inter-organisational workflows on a distributed ledger, with the possibility of adding selectively shared verifiable data to the workflow instances' documentation. On data level, we base our approach on semantic workflow and data modelling, augmented with hashing. As system components, we use a distributed ledger as consensus-based shared database for workflow documentation and data verification, and RESTful APIs for sharing data with different privacy and publicity requirements. We evaluate our approach using a load test based in a real-world logistics setting.
Access control management in a System of Systems---i.e., a collaborative environment composed of a multitude of distributed autonomous organizations---is a challenging task. To answer the challenge, in this paper we propose a novel approach that incorporates semantic technologies in the Attribute-Based Access Control (ABAC) approach. Building on the basic principles of ABAC, our approach allows for a highly expressive modeling of the context in which access decisions are made, by providing mechanisms to describe rich relationships among entities, which can evolve over time. In addition, our system works in a truly decentralized manner, which makes it suitable for geographically distributed enterprise systems. We show the feasibility in practice of our approach through some experimental results.
David Last, Michael Atighetchi, Partha Pal, Ryan Toner
The US military is focused on transitioning its warf-ighting philosophy towards the Multi-Domain Command and Control (MDC2) concept, which integrates lands, sea, air, space, and cyberspace forces into a unified planning and execution structure. This structure depends on reliable exchange of plans and intelligence reports, which is hindered by the development of adversary capabilities in the areas of radio jamming and other communications-denying technologies. The battlefield of the future will consist of dispersed units with intermittent, constrained communications who nevertheless need to maintain a consistent view of shared plans and information. We are developing a proof-of-concept prototype MDC2 system to explore the requirements and limitations of a solution in this space. There are many distributed database solutions that could be used for this prototype; upon investigation, we believe that Distributed Ledger Technologies (DLT) are an ideal fit for the particular constraints of this use case. We have selected Hyperledger Fabric as the particular DLT implementation on which we are building this prototype. As part of this research, we are developing a Hyperledger-based prototype as well as a baseline implementation that reflects how the DoD handles this process today. We will use both of these systems in a series of experiments that evaluate how well they perform in the areas of database consistency, constrained tactical networks, and conditional authorities, and we will measure their performance using a suite of metrics that will allow us to compare the DLT-based prototype with the baseline system. This paper outlines the challenges we will address through this research; the completed research will encompass our solutions to these challenges.
DELTA is a project funded by the Valencian Institute for Business Competitiveness (IVACE) and the European Union through the European Regional Development Fund (FEDER). DELTA project is aimed at bringing companies closer to the use of different disruptive technologies such as Blockchain / Distributed Ledger Technologies (DLT). To achieve its goal, DELTA will provide: A software tool for automating the deployment of DLT networks, regardless of the number of required nodes, or the process of joining an existing network. A modular mechanism that allows the synchronization of DLTs with databases. The goal of this mechanism is to ease and improve the way data is retrieved from a DLT ledger. An accountability tool for shared environments for the exchange of services that brings in some of the most important characteristics of blockchain/DLTs: facilitating auditing and accountability by each participant, use of tokens, etc. This document corresponds to a poster of the project as one of the dissemination activities.
Service fulfillment for clients increasingly involves cooperation between information technology (IT) systems. Designing such solutions requires an architectural approach that ensures symmetry between the communicating parties. For the design of such systems, the author introduces the 1+5 architectural views model. The model contains three new architectural views. For business process modeling, it ensures the integrated processes view. Integration aspects cover two additional views: integrated services, and contracts. Moreover, new stereotypes and tagged values have been added to the unified modeling language (UML). The author has introduced two profiles: UML profile for integration flows, and UML profile for distributed ledger deployment. Communication between systems requires flows that arrange mediation mechanisms. The paper describes an integration flow diagram that extends a UML activity diagram. In the case of blockchain, the author has proposed the smart contract design pattern. The paper describes three case studies that have employed the model to design various solutions. The 1+5 model has proven to be well suited for designing both centralized integration environments with enterprise service bus (ESB) and distributed blockchain solutions with peer-to-peer (P2P) connections.
Oct 13, 2021·Proceedings of the Satellite Division's International Technical Meeting (Online)/Proceedings of the Satellite Division's International Technical Meeting (CD-ROM)
RTK technology is now expanding from the traditional geo-spatial communities (such as, surveying applications, construction machine and precision farming) to automotive markets, and is becoming the key and essential component for autonomous driving. Traditionally, RTK corrections, normally in RTCM standard format, are generated from a centralized server using a complicated GNSS algorithm (for example, VRS (Virtual Reference Station) or MAC (Master Auxiliary Correction)) and the raw GNSS measurements from a set of GNSS reference stations (normally in the order of tens to hundreds). Due to the computational and network connection limitations, such systems (for example, Trimble’s VRSNet, Leica’s SpiderNET and Topcon’s TopNET) to provide RTK services, can only handle hundreds’ GNSS reference stations and thousands of user connections for RTK corrections. Also due to the complexity of algorithms to generate the corrections and operating a GNSS network, nowadays, RTK correction services are only locked by government institutions and large private companies. Or you need to setup a base station by yourself, which requires a lot of professional experience, thus it doesn't scale, and not applicable sometimes. The rapid development of autonomous driving market requires a large scale (national-wide or global) RTK network correction service, for example, Qianxun SI is spending huge efforts to build a nationalwide RTK correction service in China, especially design for autonomous driving market in China. This paper describe a new network model---PAS(Precision as Service). PAS employs a blockchain secured by a Proof-of-Stake and Proof-of-Accuracy (POA) hybrid as the consensus model. Proof-of-Stake(POS) is a consensus protocol widely used in recent blockchain projects. In our setup, service provider miners (validator, v-node) need to stake tokens to participate in system consensus. Each node will have its chance to produce blocks based on the BLS algorithm weighted by the staked token. We use the BLS algorithm for fast and reliable BFT-like (Byzantine Fault Tolerant) consensus. Multiple parties use threshold signature to reach an agreement on a blockchain proposal. The staking will also improve economic security by punishing any misbehaving validators. Anyone who owns a PAS token can bond (or delegate) their coins and become a validator, making the validator set open and permissionless. Similar to POW, POA requires external resource consumption to add entropy to the system. This external resource is in the form of physical geospatial coordinates. It is unique, computationally inexpensive, yet fully decentralized available to a large group of people. With very affordable RTK hardware, each base station miner can provide accurate RTK location streaming data with their unique geospatial coordinates. Service provider miners collect those streaming data, verifying the data's accuracy relative to their physical position, creating proof of accurate geographic span in a cryptographically secure way. POS and POA's combination is to create a fast, scalable, and secure blockchain for various applications on top of it. BLS signature By using a curve pair, BLS signature can be used to verify that the point pairs on the two (or the same) curves conform to the multiplicative commutative law: e(P, Q) ? n e(x×P, Q) = e(P, x×Q). The threshold signature (threshold sig) is essentially the signature method of m-of-n. Under the condition that m signatures are known, a unique and valid signature can be synthesized. The combination of any m signature fragments is the same verifiable signature. If fewer than m fragments are shared on the network, no individual will know the full signature. So even with many parties, the BLS signature size could be as small as the size of one signature. That will improve the efficiency of data storage of blockchain-based systems. Also, the BLS signature could be viewed as a robust random seed, as any party can not guess the combined signature, yet it can be verified quickly by everyone. Token economics Token will play an essential role inside the PAS platform. The native token in the PAS platform is called PCS. PCS's primary functions are in staking, payment method for all applications or services in the PAS platform. PCS tokens will also be used to pay transaction fees and the reward for miners and validators. Reward Types Reward Users of PCS stake tokens to subsidize operating and capital expenditures. A reward can happen in two ways. A. Stakers can stake tokens to active Service Provider Miner. Each staked token will be rewarded proportionally according to the set inflation ratio. B. Base Station Miner can uniquely bind to a Service Provider Miner. Once bound, Base Station Miner will stream accuracy RTK data to Service Provider Miner. Service Provider Miner will validate the data and use the combined geospatial RTK coverage map inside the block proposal for additional token reward, besides the staked token reward. In return, Service Provider Miner will distribute mining rewards back to Base Station Miners. Additionally, Service Provider can provide accurate location service to end customer such as surveyor, autonomous vehicle, drone, etc. Service Providers can market their service to an intended user group and create a service payment plan. Service Provider's revenue can be split among Base Station Miner in a preset distribution contract, in the form of a smart contract in PAS Network, or even an off-chain contract. Limits on Number of Validators At the PAS Network's initial stage, the number of validators will be limited to a certain number (e.g., 64). The number of validators will increase gradually as the PAS Network coverage increases. The selection of validators will be based on the balanced consideration of staked token and RTK map coverage area associated with that validator. Staked token RTK data stream Services Provider Staking reward Data reward Base station miner Staker Reward System A Service Provider Miner commits to provide services for at least time t and intends to earn service income r based on staked token T. The minimal number of Base Station Miners is about 10,000. To ensure robust service with enough system redundancy, the ideal number of base station miners could be 3x. Base Station Miners' density may vary from area to area, as the demand for RTK service may change dramatically.
Matea Vasilj, Sven Skender, Mia Jurdana, Marko Horvat
Student non-profit organizations are a specific type of small associations that congregate students from diverse backgrounds around a common purpose. These organizations are non-profit driven, autonomous, and typically have largely similar statutes and regulations. In the context of software engineering, information systems that support their business processes have similar software requirements specifications. DESPRO is a web-based platform that fully supports principal use cases of students' non-profit organizations. The platform has three uses: accounting, voting, and fundraising management. DESPRO allows such organizations to begin with their principal operations practically immediately without unnecessary overhead. Unique features that distinguish DESPRO from other similar systems are: 1) lightweight and streamlined deployment process, 2) minimal required remote maintenance, 3) pre-defined functionalities specifically suited for student non-profit organizations, 4) user anonymity customized to specific functional requirements, 5) voting without prior user registration. The platform was developed with open-source technologies Node.js, Vue.js, Vuetify, Bootstrap, Sequalize, Axios, Web3, MariaDB, and smart contracts for Ethereum. It is freely available for noncommercial use by contacting the first author.
Amit K. Chopra, Samuel H. Christie, Munindar P. Singh
Interaction-Oriented Programming (IOP) refers to multiagent concepts, languages, and programming models for engineering applications that are characterized by interactions between autonomous parties. Such applications arise in domains such as e-commerce, health care, and finance. Owing to the autonomy of the principals involved, such applications are conceptually decentralized. We demonstrate how to specify a decentralized application flexibly and how to engineer correct, fault-tolerant endpoints (agents) for the principals in a straightforward manner. Notably, the entire application is realized as agents communicating over an unordered, unreliable messaging infrastructure (our implementations in fact use UDP). IOP departs from traditional distributed systems approaches that rely on guarantees in the application's communication infrastructure, e.g., for ordering and fault tolerance. Notably, IOP shows how to address application semantics, the holy grail of distributed systems.
Hemant Kumar Srivastava, Ravi Yadav, Gaurav Baranwal
The paper presents an Ethereum based service selection framework that is decentralized in nature and aids people in finding the best services using a smart contract. We have used Solidity, a language to develop the smart contract for Ethereum, to tackle the problem that occurs in broker-based systems or centralized systems. As for the result, we show that the functionalities performed by a broker can be implemented on Ethereum smart contract. We present a methodology that one can refer to develop Ethereum smart contract for service selection.
Access control management in a collaborative environment composed of a multitude of distributed autonomous organizations is a challenging task. To answer the challenge, in this paper we propose a novel approach that incorporates semantic technologies in the Attribute-Based Access Control (ABAC) approach. Building on the basic principles of ABAC, our approach allows for a highly expressive modeling of the context in which access decisions are made, by providing mechanisms to describe rich relationships among entities, which can evolve over time. In addition, our system works in a truly decentralized manner, which makes it suitable for geographically distributed enterprise systems. We show the feasibility in practice of our approach through some experimental results.
ABSTRACT The formalization of the REA2 ontology presented in this paper offers a minimal set of operationalized semantics for a single white-box model relevant to all business stakeholders independent of their role or involvement in economic activities. This paper's theoretical innovations are the use of MERODE to model increment and decrement semantics as fundamental stand-alone concepts that simultaneously affect economic resources, event, agents, and the semantics of the stock-flow, participation, and ownership associations and the formalization of the REA axioms as executable finite state machines. MERODE's possibilities for model execution through fast prototyping allowed validation through the modeling of an archetypical exchange scenario. Both innovations contribute to the reliability of a generic semantic model for finance and logistics in both the traditional, as well as the sharing, economy, thus promoting traceability and accountability in value networks and supply chains supported by both centralized and decentralized ledger technologies.
Summary In smart home systems (SHS), devices intercommunicate to create an intelligent environment that can monitor the inhabitant's health state and provide adapted services. However, existing health monitoring systems (HMS) do not provide adapted services to the patient autonomy degree. Furthermore, in these critical systems, the Quality of Service (QoS) aspect is very important; therefore, service level agreements (SLA) are the best solution to define and guarantee the expected QoS levels, nevertheless, existing SLA specification languages lack expressiveness in terms of user preference specification, dynamic service management and pricing. In this work, we propose an elderly health state‐aware SHS to offer adapted services according to the elderly health state, it is based on three main parts: (a) the functional autonomy measurement system (SMAF) for calculating the inhabitant's profile or autonomy degree, (b) domain‐specific language (DSL) for SLA that aims to increase patient‐awareness through the use of preferences, facilitate the SLA management using microservices, and manage the QoS dynamically using multilevel SLA (ML‐SLA) concept, and (c) smart contracts for the provision of adapted services and the verification of SLA terms.
Jan 1, 2021·Proceedings of the ... Annual Hawaii International Conference on System Sciences/Proceedings of the Annual Hawaii International Conference on System Sciences
Cristian Gómez, Francisco Javier Pérez Blanco, Juan M. Vara, Valeria De Castro · 5 authors
Administrations are constantly making great efforts to cope with the right of citizens to high-quality e-Government services. Since the advent of blockchain and smart contracts, they are trying to incorporate these technologies into their service offerings, which results in a complex task due to their nature and their inherent complexity. On the other hand, business and business process modeling facilitates the understanding and agreement between the different parties involved in the design of e-government services. All this given, this work introduces a model-based proposal to ease the integration of smart contracts into e-government services.
Claudio A. Ardagna, Marco Anisetti, Barbara Carminati, Ernesto Damiani · 6 authors
Lack of trustworthiness is a major limit of microservice-based systems, where service composition is mainly driven by functional requirements. In this paper, we propose an approach where composite service certification meets blockchain, to support continuous and trustworthy verification of non-functional requirements. A certification process for composite services is then introduced at the basis of an audit process aiming to support certificates with stable properties. Trustworthiness is built on the blockchain, used as a platform for coordinating collaboration among involved parties such as service orchestrators, certification authorities, and auditors.
Markus Schinle, Christina Erler, Philip Nicolai Andris, Wilhelm Stork
The digitization of business processes makes it possible to automate and monitor their execution in real-time and thus to optimize them. However, for inter-organizational business processes the lack of trust and transparency between organizations makes it difficult to realize this potential. Distributed Ledger Technology addresses this issue by design, which makes it attractive as a platform for the execution of digitized inter-organizational business processes. In research, especially the mapping of standardized business process notations on smart contract definition languages is discussed recently, to ease the process development for different kinds of stakeholders. Within this work, we present an approach for the integration, execution and monitoring of modeled business processes based on Hyperledger Fabric’s chaincode. Our aim is the reduction of required knowledge about this framework for the integration of business processes in such systems. Therefore, we introduce a reverse translation approach to enable the monitoring of processes defined within a chaincode by providing BPMN 2.0 models, that specify business processes as graphical representations.
S. Sridevi, G. R. Karpagam, Vinoth Kumar B., Uma Maheswari J
The blockchain is an incorruptible digital ledger of economic transactions that can be programmed to record not just financial transactions but virtually everything of value. Blockchain technology makes breakthroughs in business intelligence in many areas such as banking sector, finance, judiciary, commerce, and information technology. Web service compositions have a revolutionary impact on business intelligence by enabling loose coupling, data consolidation from diverse sources, consolidation of information under a single roof, easing ad-hoc querying and reporting. The objective of current work is to investigate the applicability of blockchain for the semantic web service composition process. The paper focuses on design of conceptual architecture and the algorithm for QoS-aware semantic web service composition (SWSC) using blockchain.
With the fast development of information technologies, traditional value-added chain business models are shifting to service-based applications (SBAs) to cope with ever-changing user behaviors and the modern social system. An SBA allows an organization to utilize external and distributed resources to achieve its business goals, especially when the Internet of Thing (IoT) will soon become mainstream. However, the development of SBAs is at its early stage with a number of unsolved issues, such as the availability of effective methods for services selection and composition, semantic representation of specifications, and security assurances. This article aims to address two main issues in SBAs: 1) the standardization of formulation and 2) the security assurance. A systematic method is proposed to formulate the specifications of services, the prevalent blockchain technology (BCT) is adopted to enable SBAs, and the proposed specification patterns and BCT are integrated as a BCT-based quality-of-service (QoS) framework to support service selections and workflow compositions.
Correct-by-Construction Casper (CBC Casper) is an Ethereum candidate consensus protocol undergoing active design and development. We present a formalization of CBC Casper using the Coq proof assistant that includes a model of the consensus protocol and proofs of safety and non-triviality protocol properties. We leverage Coq's type classes to model CBC Casper at various levels of abstraction. In doing so, we 1) illuminate the assumptions that each protocol property depends on, and 2) reformulate the protocol in general, mathematical terms. We highlight two advantages of our approach: 1) from a proof engineering perspective, it enables a clean separation of concerns between theory and implementation; 2) from a protocol engineering perspective, it provides a rigorous, foundational understanding of the protocol conducive to finding and proving stronger properties. We detail one such new property: strong non-triviality.
The increasing use of information and communication technology over the last decade has driven a new range of information needs in business. A number of these software systems in deployment, however, suffer from detrimental unintended integrity and consistency compromise due to anomaly infestation. Primarily, the effects of this usually culminate in unpredictable and catastrophic results, which must be adequately checked to yield highly dependable software. This paper proposes a unified framework for analyzing propagations of anomalies in software systems employing ontology to characterize, categorize, and identify these errors; also, to provide guidelines for the implementation of the proposed solution. The generic approach captures the conventional semantics and structure of different types of anomalies with the notion of anomaly ontology. The prototype Ontology-based Software Anomaly Propagation Detection System (OBSAPDS) was built with the Protégé 4.3 knowledge acquisition tool, and Java programming languagPe was used for the development of the application and MySQL Server as the back en--gine. The combination of the domain ontology in Protégé and inference rules in Jena formed the knowledge system for the elicitation and the validation of domain facts. Besides, a proof-of-concept evaluation of the proposed framework confirmed how efficiently the approach could discover and resolve anomalies for different types of systems through demonstration. The division by zero error and the read access to uninitialized error conditions served as case studies.Keywords: Ontology, software systems, anomaly propagation
Jan 1, 2020·Proceedings of the ... Annual Hawaii International Conference on System Sciences/Proceedings of the Annual Hawaii International Conference on System Sciences
Florian Gräbe, Niclas Kannengießer, Sebastian Lins, Ali Sunyaev
Distributed Ledger Technology (DLT) enables a new way of inter-organizational collaboration via a shared and distributed infrastructure. Meanwhile, there is plenty of DLT designs (e.g., Ethereum, IOTA), which differ in their capabilities to meet use case requirements. A structured comparison of DLT designs is required to support the decision for an appropriate DLT design. However, existing criteria and processes are abstract or not suitable for an in-depth comparison of DLT designs. We select and operationalize DLT characteristics relevant for a comprehensive comparison of DLT designs. Furthermore, we propose a comparison process, which enables the structured comparison of a set of DLT designs according to application requirements. The proposed process is validated with a use case analysis of three use cases. We contribute to research and praxis by introducing ways to operationalize DLT characteristics and generate a process to compare different DLT designs accordingly to their suitability in a use case.