scholarly journals Clover: An anonymous transaction relay protocol for the bitcoin P2P network

2021 ◽  
Author(s):  
Federico Franzoni ◽  
Vanesa Daza
Keyword(s):  
Real Life ◽  
Experimental Results ◽  
P2p Network ◽  
User Privacy ◽  
Spread Pattern ◽  
Effective Design

AbstractThe Bitcoin P2P network currently represents a reference benchmark for modern cryptocurrencies. Its underlying protocol defines how transactions and blocks are distributed through all participating nodes. To protect user privacy, the identity of the node originating a message is kept hidden. However, an adversary observing the whole network can analyze the spread pattern of a transaction to trace it back to its source. This is possible thanks to the so-called rumor centrality, which is caused by the symmetry in the spreading of gossip-like protocols. Recent works try to address this issue by breaking the symmetry of the Diffusion protocol, currently used in Bitcoin, and leveraging proxied broadcast. Nonetheless, the complexity of their design can be a barrier to their adoption in real life. In this work, we propose Clover, a novel transaction relay protocol that protects the source of transaction messages with a simple, yet effective, design. Compared to previous solutions, our protocol does not require building propagation graphs, and reduces the ability of the adversary to gain precision by opening multiple connections towards the same node. Experimental results show that the deanonymization accuracy of an eavesdropper adversary against Clover is up to 10 times smaller compared to Diffusion.

scholarly journals A Novel Concept Acquisition Approach Based on Formal Contexts

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Ting Qian ◽  
Ling Wei
Keyword(s):  
Data Analysis ◽  
Formal Concept Analysis ◽  
Real Life ◽  
Experimental Results ◽  
New Method ◽  
Concept Acquisition ◽  
Formal Concept ◽  
Knowledge Processing ◽  
Formal Concepts ◽  
Novel Concept

As an important tool for data analysis and knowledge processing, formal concept analysis (FCA) has been applied to many fields. In this paper, we introduce a new method to find all formal concepts based on formal contexts. The amount of intents calculation is reduced by the method. And the corresponding algorithm of our approach is proposed. The main theorems and the corresponding algorithm are examined by examples, respectively. At last, several real-life databases are analyzed to demonstrate the application of the proposed approach. Experimental results show that the proposed approach is simple and effective.

Opportunistic Networks

2013 ◽  
Vol 5 (2) ◽  
pp. 11-26
Author(s):  
Radu Ioan Ciobanu ◽  
Ciprian Dobre
Keyword(s):  
Mobile Devices ◽  
Short Range ◽  
Data Dissemination ◽  
Real Life ◽  
Opportunistic Networks ◽  
User Privacy ◽  
Relevant Work ◽  
Exchange Data ◽  
Carry And Forward ◽  
Mobile Collaboration

When mobile devices are unable to establish direct communication, or when communication should be offloaded to cope with large throughputs, mobile collaboration can be used to facilitate communication through opportunistic networks. These types of networks, formed when mobile devices communicate only using short-range transmission protocols, usually when users are close, can help applications still exchange data. Routes are built dynamically, since each mobile device is acting according to the store-carry-and-forward paradigm. Thus, contacts are seen as opportunities to move data towards the destination. In such networks data dissemination is usually based on a publish/subscribe model. Opportunistic data dissemination also raises questions concerning user privacy and incentives. In this the authors present a motivation of using opportunistic networks in various real life use cases, and then analyze existing relevant work in the area of data dissemination. The authors present the categories of a proposed taxonomy that captures the capabilities of data dissemination techniques used in opportunistic networks. Moreover, the authors survey relevant techniques and analyze them using the proposed taxonomy.

scholarly journals Keywords-Driven and Popularity-Aware Paper Recommendation Based on Undirected Paper Citation Graph

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Hanwen Liu ◽  
Huaizhen Kou ◽  
Chao Yan ◽  
Lianyong Qi
Keyword(s):  
Recommender Systems ◽  
Recommender System ◽  
Large Scale ◽  
Real Life ◽  
Research Field ◽  
Experimental Results ◽  
The Real ◽  
Matching Technique ◽  
Paper Citation ◽  
Citation Graph

Nowadays, scholar recommender systems often recommend academic papers based on users’ personalized retrieval demands. Typically, a recommender system analyzes the keywords typed by a user and then returns his or her preferred papers, in an efficient and economic manner. In practice, one paper often contains partial keywords that a user is interested in. Therefore, the recommender system needs to return the user a set of papers that collectively covers all the queried keywords. However, existing recommender systems only use the exact keyword matching technique for recommendation decisions, while neglecting the correlation relationships among different papers. As a consequence, it may output a set of papers from multiple disciplines that are different from the user’s real research field. In view of this shortcoming, we propose a keyword-driven and popularity-aware paper recommendation approach based on an undirected paper citation graph, named PRkeyword+pop. At last, we conduct large-scale experiments on the real-life Hep-Th dataset to further demonstrate the usefulness and feasibility of PRkeyword+pop. Experimental results prove the advantages of PRkeyword+pop in searching for a set of satisfactory papers compared with other competitive approaches.

scholarly journals Exploring the Mechanisms of the Spatiotemporal Invasion of Tuta absoluta in Asia

Agriculture ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 124 ◽  
Author(s):  
Ritter A. Guimapi ◽  
Ramasamy Srinivasan ◽  
Henri E. Tonnang ◽  
Paola Sotelo-Cardona ◽  
Samira A. Mohamed
Keyword(s):  
High Speed ◽  
Real Life ◽  
Initial Point ◽  
The Philippines ◽  
Control Measures ◽  
Tuta Absoluta ◽  
Invasive Pest ◽  
Spread Pattern ◽  
People Movement ◽  
Not At Risk

International crop exchange always brings the risk of introducing pests to countries where they are not yet present. The invasive pest Tuta absoluta (Meyrick 1917), after taking just a decade (2008–2017) to invade the entire Africa continent, is now continuing its expansion in Asia. From its first detection in Turkey (2009), the pest has extended its range of invasion at a very high speed of progression to the southeast part of Asia. This study adopted the cellular automata modelling method used to successfully predict the spatiotemporal invasion of T. absoluta in Africa to find out if the invasive pest is propagating with a similar pattern of spread in Asia. Using land cover vegetation, temperature, relative humidity and the natural flight ability of Tuta absoluta, we simulated the spread pattern considering Turkey as the initial point in Asia. The model revealed that it would take about 20 years for the pest to reach the southeast part of Asia, unlike real life where it took just about 10 years (2009–2018). This can be explained by international crop trade, especially in tomatoes, and movement of people, suggesting that recommendations and advice from the previous invasion in Europe and Africa were not implemented or not seriously taken into account. Moreover, some countries like Taiwan and the Philippines with suitable environmental condition for the establishment of T. absoluta are not at risk of natural invasion by flight, but quarantine measure must be put in place to avoid invasion by crop transportation or people movement. The results can assist policy makers to better understand the different mechanisms of invasion of T. absoluta in Asia, and therefore adjust or adapt control measures that fit well with the dynamic of the invasive pest observed.

E-MsNFIS: Efficient Negative Frequent Itemsets Mining Based on Multiple Minimum Supports

2013 ◽  
Vol 411-414 ◽  
pp. 386-389 ◽  
Author(s):  
Tian Tian Xu ◽  
Xiang Jun Dong
Keyword(s):  
Association Rules ◽  
Real Life ◽  
Frequent Itemsets ◽  
Negative Association ◽  
Experimental Results ◽  
New Method ◽  
Minimum Support ◽  
Frequent Itemsets Mining ◽  
Negative Association Rules ◽  
Multiple Minimum Supports

Negative frequent itemsets (NFIS) like (a1a2¬a3a4) have played important roles in real applications because we can mine valued negative association rules from them. In one of our previous work, we proposed a method, namede-NFISto mine NFIS from positive frequent itemsets (PFIS). However,e-NFISonly uses single minimum support, which implicitly assumes that all items in the database are of the same nature or of similar frequencies in the database. This is often not the case in real-life applications. So a lot of methods to mine frequent itemsets with multiple minimum supports have been proposed. These methods allow users to assign different minimum supports to different items. But these methods only mine PFIS, doesn’t consider negative ones. So in this paper, we propose a new method, namede-msNFIS, to mine NFIS from PFIS based on multiple minimum supports. E-msNFIScontains three steps: 1) using existing methods to mine PFIS with multiple minimum supports; 2) using the same method ine-NFISto generate NCIS from PFIS got in step 1; 3) calculating the support of these NCIS only using the support of PFIS and then gettingNFIS. Experimental results show that thee-msNFISis efficient.

scholarly journals SIMPLIFICATION AND VERIFICATION OF DYNAMIC EQUATIONS OF MOVEMENT OF AN AUTONOMUS UNDERWATER VEHICLE

2019 ◽  
pp. 43-48
Author(s):  
Martin Varga
Keyword(s):  
Simulation Model ◽  
Dynamic Model ◽  
Autonomous Underwater Vehicle ◽  
Computer Modelling ◽  
Real Life ◽  
Underwater Vehicle ◽  
Industrial Robots ◽  
Experimental Results ◽  
Dynamic Equations ◽  
Basic Step

Urgency of the research. Currently, most machines go through computer modelling and simulation phase in their development cycle. The ability to formulate simple yet effective models helps to both decrease development cost and time. Target setting. Today many tasks are being accomplished by robots whether mobile robots or industrial robots. To simulate the behaviour of these robots a dynamic model is needed. These models can be very complex and the parameters to fill all the equations can be difficult to find, therefore simplifications need to be implemented and verified so that the models are still accurate. Actual scientific researches and issues analysis. A basic step in the development of new products is the simulation and modeling phase. Development of a computer model prior to development of a physical prototype saves time and resources. Unfortunately, some models can be very complex and require parameters only acquirable from tests on physical systems. That is why often these models need to be heavily simplified which can lead to imprecise results. Often, verification of the model is needed. One of such systems is the dynamic model of an Autonomous underwater vehicle (AUV). Uninvestigated parts of general matters defining. This article focuses on verification of a highly simplified dynamic simulation model of AUV. The research objective. The aim of these research was to model a simplified dynamic model of an AUV moving through fluid with nonnegligible viscous properties and verifie the model by comparing simulation results with experimental results obtained by testing on the real AUV. The statement of basic materials. The analysis consists of an attempt to summarise the possible ways to simplify a general dynamic equation for movement of an AUV in a fluid with nonnegligible viscous properties and showing, that even such simplified model stays usable and bring with it reduction in complexity. Conclusions. This article shows the basic dynamic equations for describing the movement of a general AUV in a fluid with nonnegligible viscous properties and the possible simplification of this equation in regard to a specific construction of a real world AUV. The results gathered from the simulation model are then compared to experimental results performed on the physical AUV with the conclusion, that both datasets are matching within reasonable margins. This article serves as a good reminder of the importance and benefits of well establishing simplifications in a model of a real-life system.

scholarly journals Furniture Model Creation Through Direct Teaching to a Mobile Robot

2008 ◽  
Vol 20 (2) ◽  
pp. 213-220 ◽  
Author(s):  
Kimitoshi Yamazaki ◽  
◽  
Takashi Tsubouchi ◽  
Masahiro Tomono ◽  
◽  
...  
Keyword(s):  
Mobile Robot ◽  
Mobile Robots ◽  
Real Life ◽  
Experimental Results ◽  
Sensor Data ◽  
Small Object ◽  
Laser Range Finder ◽  
Range Finder ◽  
Laser Range ◽  
Direct Teaching

In this paper, a modeling method to handle furniture is proposed. Real-life environments are crowded with objects such as drawers and cabinets that, while easily dealt with by people, present mobile robots with problems. While it is to be hoped that robots will assist in multiple daily tasks such as putting objects in into drawers, the major problems lies in providing robots with knowledge about the environment efficiently and, if possible, autonomously.If mobile robots can handle these furniture autonomously, it is expected that multiple daily jobs, for example, storing a small object in a drawer, can be performed by the robots. However, it is a perplexing process to give several pieces of knowledge about the furniture to the robots manually. In our approach, by utilizing sensor data from a camera and a laser range finder which are combined with direct teaching, a handling model can be created not only how to handle the furniture but also an appearance and 3D shape. Experimental results show the effectiveness of our methods.

A Novel Fuzzy Integrated Customer Needs Prioritization Software Tool for Effective Design of Online Shopping Websites

2017 ◽  
Vol 8 (4) ◽  
pp. 23-42
Author(s):  
Ashish K. Sharma ◽  
Sunanda Khandait
Keyword(s):  
Decision Making ◽  
Quality Function Deployment ◽  
Online Shopping ◽  
Real Life ◽  
Software Tool ◽  
Visual Basic ◽  
Website Design ◽  
Customer Needs ◽  
Technical Requirements ◽  
Effective Design

Albeit, online shopping has grown much recently, users' rate of satisfaction has declined due to the ineffective design of online shopping websites. Thus, the companies involved are craving for well-designed websites. Effective website design involves decision making and thus this paper considers Quality Function Deployment (QFD) as it is a strong decision-making tool. However, QFD uses crisp scoring approach that generates uncertainty and vagueness resulting in impreciseness and inconsistency in results. The issue can be addressed using fuzzy integration. QFD involves prioritization of Customer Needs (CNs) and Technical Requirements (TRs). However, the paper focuses on only CNs prioritization. Also, the existing software's lack the indispensable fuzzy support feature to handle the uncertainty and vagueness. Thus, the paper presents a novel fuzzy integrated customer needs prioritization software tool. The tool is built using Visual Basic Dot Net (VB.Net) and MS-Access. A real-life example is presented to demonstrate the viability of the software tool.

Chance Discovery as Analogy Based Value Sensing

2010 ◽  
Vol 1 (1) ◽  
pp. 44-57 ◽  
Author(s):  
Yukio Ohsawa ◽  
Akinori Abe ◽  
Jun Nakamura
Keyword(s):  
Decision Making ◽  
Real Life ◽  
Abductive Reasoning ◽  
Experimental Results ◽  
Logical Framework ◽  
Chance Discovery ◽  
Analogical Thinking ◽  
Life Chance ◽  
Basic Engine ◽  
Human Decision

The authors are finding rising demands for sensing values in existing/new events and items in the real life. Chance discovery, focusing on new events significant for human decision making, can be positioned extensively as an approach to value sensing. This extension enables the innovation of various artificial systems, where human’s talent of analogical thinking comes to be the basic engine. Games for training and activating this talent are introduced, and it is clarified that these games train the an essential talent of human for chance discovery, by discussing the experimental results of these games on the logical framework of analogical abductive reasoning.

Chance Discovery as Analogy Based Value Sensing

2012 ◽  
pp. 43-56
Author(s):  
Yukio Ohsawa ◽  
Akinori Abe ◽  
Jun Nakamura
Keyword(s):  
Decision Making ◽  
Real Life ◽  
Abductive Reasoning ◽  
Experimental Results ◽  
Logical Framework ◽  
Chance Discovery ◽  
Analogical Thinking ◽  
Life Chance ◽  
Basic Engine ◽  
Human Decision

The authors are finding rising demands for sensing values in existing/new events and items in the real life. Chance discovery, focusing on new events significant for human decision making, can be positioned extensively as an approach to value sensing. This extension enables the innovation of various artificial systems, where human’s talent of analogical thinking comes to be the basic engine. Games for training and activating this talent are introduced, and it is clarified that these games train the an essential talent of human for chance discovery, by discussing the experimental results of these games on the logical framework of analogical abductive reasoning.

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