scholarly journals Is it Possible to Verify if a Transaction is Spendable?

2021 ◽  
Vol 4 ◽  
Author(s):  
Marcelo Arenas ◽  
Thomas Reisenegger ◽  
Juan Reutter ◽  
Domagoj Vrgoč
Keyword(s):  
Building Blocks ◽  
Main Building ◽  
Scripting Language ◽  
And Performance

With the popularity of Bitcoin, there is a growing need to understand the functionality, security, and performance of various mechanisms that comprise it. In this paper, we analyze Bitcoin’s scripting language, Script, that is one of the main building blocks of Bitcoin transactions. We formally define the semantics of Script, and study the problem of determining whether a user-defined script is well-formed; that is, whether it can be unlocked, or whether it contains errors that would prevent this from happening.

scholarly journals TESSA: design and implementation of a platform for situational sea awareness

2017 ◽  
Vol 17 (2) ◽  
pp. 185-196
Author(s):  
Mario Scalas ◽  
Palmalisa Marra ◽  
Luca Tedesco ◽  
Raffaele Quarta ◽  
Emanuele Cantoro ◽  
...  
Keyword(s):  
Situational Awareness ◽  
Building Blocks ◽  
Ministry Of Education ◽  
End User ◽  
Performance Requirements ◽  
Platform Architecture ◽  
Front End ◽  
Critical Issues ◽  
And Performance ◽  
Key Aspects

Abstract. This article describes the architecture of sea situational awareness (SSA) platform, a major asset within TESSA, an industrial research project funded by the Italian Ministry of Education and Research. The main aim of the platform is to collect, transform and provide forecast and observational data as information suitable for delivery across a variety of channels, like web and mobile; specifically, the ability to produce and provide forecast information suitable for creating SSA-enabled applications has been a critical driving factor when designing and evolving the whole architecture. Thus, starting from functional and performance requirements, the platform architecture is described in terms of its main building blocks and flows among them: front-end components that support end-user applications and map and data analysis components that allow for serving maps and querying data. Focus is directed to key aspects and decisions about the main issues faced, like interoperability, scalability, efficiency and adaptability, but it also considers insights about future works in this and similarly related subjects. Some analysis results are also provided in order to better characterize critical issues and related solutions.

High Yield Assembly of Compliant MEMS Snap Fasteners

2008 ◽  
Author(s):  
Rakesh Murthy ◽  
Aditya N. Das ◽  
Dan O. Popa
Keyword(s):  
Self Assembly ◽  
Building Blocks ◽  
Deformation Energy ◽  
High Yield ◽  
3 Dimensional ◽  
Lab Experiments ◽  
Trade Offs ◽  
Robotic Cells ◽  
And Performance ◽  
Important Design

Heterogeneous assembly at the microscale has recently emerged as a viable pathway to constructing 3-dimensional microrobots and other miniaturized devices. In contrast to self-assembly, this method is directed and deterministic, and is based on serial or parallel microassembly. Whereas at the meso and macro scales, automation is often undertaken after, and often benchmarked against manual assembly, we demonstrate that deterministic automation at the MEMS scale can be completed with higher yields through the use of engineered compliance and precision robotic cells. Snap fasteners have long been used as a way to exploit the inherent stability of local minima of the deformation energy caused by interference during part mating. In this paper we assume that the building blocks are 2 1/2 -dimensional, as is the case with lithographically microfabricated MEMS parts. The assembly of the snap fasteners is done using μ3, a multi-robot microassembly station with unique characteristics located at our ARRI’s Texas Microfactory lab. Experiments are performed to demonstrate that fast and reliable assemblies can be expected if the microparts and the robotic cell satisfy a so-called “High Yield Assembly Condition” (H.Y.A.C.). Important design trade-offs for assembly and performance of microsnap fasteners are discussed and experimentally evaluated.

Drawing with Performance Prediction

1995 ◽  
Author(s):  
Peter Schwenn ◽  
George Hazen
Keyword(s):  
Design Optimization ◽  
Performance Prediction ◽  
Fold Increase ◽  
Building Blocks ◽  
Programming Environment ◽  
Immediate Feedback ◽  
Surface Stability ◽  
Performance Constraints ◽  
And Performance ◽  
The One

We describe some advances in Performance Prediction Programs - "PPP"1 for sailing yachts2 - primarily integrating PPP analysis into drawing and providing new sculpting operations in which fairness and desired hydrostatic and on her performance determining characteristics are maintained - the shape remains a boat or a ship of the desired kind during reshaping. Our building blocks for such an integration are: a thousand-fold increase in PPP speed3, new editing tools which maintain Boatness4 , and an accessible modularization of the engineering physics of the PPP within a new programming environment which allows immediate changes by designers. Specifically, these new functions are introduced at the boundary of Drawing and the PPP: - A live knotmeter is displayed with each design variant on the drawing boar, - alongside it's antagonist - Rating. - Continuously updated hydrotatics (including the speed determining factors LSM, wetted surface, stability, prismatics, .. ) are displayed with the knotometer, with the 'positive' factors (like length) graphically opposing the 'negative' (like wetted surface.) Dimensions for PPP use are calculated automatically from the shape at hand - in particular: appendage dimensions, hydrostatics, and so forth. - Bounding limits are set for a design optimization by drawing two or more outlier yacht forms. The space in between can be explored by hand or automatically. - Local optimums of Speed against rating are provided as a 'Snap' function. This is the one dimensional version of automatic exploration for optima. - Intermediate shapes are also controlled during design optimization to maintain realism and performance constraints on type, fairness, 'look', speed producing shape measures like prismatic and displacement etc., and even handicap. - Immediate feedback is available if one chooses to exploit the new programming environment to make aero hydro model changes or extensions to the internal PPP mechanisms while drawing and exploring.

scholarly journals The Lean Startup Framework: Closing the Academic–Practitioner Divide

2020 ◽  
pp. 104225871989941 ◽  
Author(s):  
Dean A. Shepherd ◽  
Marc Gruber
Keyword(s):  
Business Model ◽  
New Ventures ◽  
Building Blocks ◽  
Market Opportunity ◽  
Research Opportunities ◽  
Main Building ◽  
Research Findings ◽  
Startup Process ◽  
Customer Development ◽  
Lean Startup

The lean startup framework is one of the most popular contributions in the practitioner-oriented entrepreneurship literature. This study seeks to generate new insights into how new ventures are started by describing the five main building blocks of the lean startup framework (business model, validated learning/customer development, minimum viable product, perseverance vs. pivoting, market-opportunity navigation), enriching the framework with existing research findings, and proposing promising research opportunities in a way that reduces the academic−practitioner divide. In so doing, we hope to enhance researchers’ understanding of the startup process; provide knowledge for educators; and, ultimately, improve the startup process for practitioners.

ptGAs—Genetic Algorithms Evolving Noncoding Segments by Means of Promoter/Terminator Sequences

1998 ◽  
Vol 6 (4) ◽  
pp. 361-386 ◽  
Author(s):  
Helmut A. Mayer
Keyword(s):  
Genetic Algorithms ◽  
Formal Analysis ◽  
Artificial Chromosome ◽  
Building Blocks ◽  
Noncoding Sequences ◽  
Np Complete ◽  
And Performance ◽  
Adaptive Crossover ◽  
Parameter Values ◽  
Experimental Comparisons

In this article we present work on chromosome structures for genetic algorithms (GAs) based on biological principles. Mainly, the influence of noncoding segments on GA behavior and performance is investigated. We compare representations with noncoding sequences at predefined, fixed locations with “junk” code induced by the use of promoter/terminator sequences (ptGAs) that define start and end of a coding sequence, respectively. AS one of the advantages of noncoding segments a few researchers have identified the reduction of the disruptive effects of crossover, and we solidify this argument by a formal analysis of crossover disruption probabilities for noncoding segments at fixed locations. The additional use of promoter/terminator sequences not only enables evolution of parameter values, but also allows for adaptation of number, size, and location of genes (problem parameters) on an artificial chromosome. Randomly generated chromosomes of fixed length carry different numbers of promoter/terminator sequences resulting in genes of varying size and location. Evolution of these ptGA chromosomes drives the number of parameters and their values to (sub)optimal solutions. Moreover, the formation of tightly linked building blocks is enhanced by self-organization of gene locations. We also introduce a new, nondisruptive crossover operator emerging from the ptGA gene structure with adaptive crossover rate, location, and number of crossover sites. For experimental comparisons of this genetic operator to conventional crossover in GAs, as well as properties of different ptGA chromosome structures, an artificial problem from the literature is utilized. Finally, the potential of ptGA is demonstrated on an NP-complete combinatorial optimization problem.

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