The theory of cognitive development from Jean Piaget (1923) is a constructivist perspective of learning that has substantially influenced cognitive science domain.Indeed it seems that constructivism is a possible trail in order to overcome the limitations of classical techniques stemming from cognitivism or connectionism and create autonomous agents, fitted with strong adaptation ability within their environment, modelled on biological organisms.Potential applications concern intelligent agents in interaction with a complex environment, with objectives that cannot be predefined.There are numerous interesting works in developmental robotics going in this direction.In this work we investigate the application of these principles to a close domain: Ambient intelligence, which is extremely challenging but which also presents interesting aspects to exploit, like the participation of human users.From the perspective of a constructivist theory, the learning agent has to build a representation of the world that relies on the learning of sensori-motor patterns starting from its own experience only.This step is difficult to set up for systems evolving in continuous environments, using raw data from sensors without a priori modelling, primarily because they face a bootstrap problem.In this paper we address this particular issue and propose a decentralized approach based on a multi-agent framework, where the system's representations are constructed through a self-organization process that handles the dynamics between experience discretization and learning.
Gyan Prakash, B. N. VYAS, Product Design Specialist, Cognizant Technology Solutions, Kolkata, India
Cloud-based outsourced storage relieves the client's load for storage management and maintenance by providing a comparably low-cost, scalable, locationindependent platform. Though, the information that clients no longer have physical control of data specifies that they are facing a potentially formidable risk for missing or corrupted data. To avoid the security risks, inspection services are serious to ensure the integrity and availability of outsourced data and to achieve digital forensics and reliability on cloud computing. Provable data possession (PDP), which is a cryptographic method for validating the reliability of data without retrieving it at an untrusted server, can be used to realize audit services. In this project, profiting from the interactive zero-knowledge proof system, the construction of an interactive PDP protocol to prevent the fraudulence of prover (soundness property) and the leakage of verified data (zero knowledge property).To prove that our construction holds these properties based on the computation Diffie-Hellman assumption and the rewindable black-box knowledge extractor. An efficient mechanism on probabilistic queries and periodic verification is proposed to reduce the audit costs per verification and implement abnormal detection timely. Also, we present an efficient method for choosing an optimal parameter value to reduce computational overheads of cloud audit services.
The InterPlanetary File System (IPFS) is a peer-to-peer distributed file system that seeks to connect all computing devices with the same system of files. In some ways, IPFS is similar to the Web, but IPFS could be seen as a single BitTorrent swarm, exchanging objects within one Git repository. In other words, IPFS provides a high throughput content-addressed block storage model, with content-addressed hyper links. This forms a generalized Merkle DAG, a data structure upon which one can build versioned file systems, blockchains, and even a Permanent Web. IPFS combines a distributed hashtable, an incentivized block exchange, and a self-certifying namespace. IPFS has no single point of failure, and nodes do not need to trust each other.
Saramago, Rodrigo Q., Meling, Hein, Jehl, Leander N.
A certification system is responsible for issuing digital credentials, which attest claims about a subject, e.g., an academic diploma. Such credentials are valuable for individuals and society, and widespread adoption requires a trusted certification system. Trust can be gained by being transparent when issuing and verifying digital credentials. However, there is a fundamental tradeoff between privacy and transparency. For instance, admitting a student to an academic program must preserve the studentâs privacy, i.e., the studentâs grades must not be revealed to unauthorized parties. At the same time, other applicants may demand transparency to ensure fairness in the admission process. Thus, building a certification system with the right balance between privacy and transparency is challenging. This paper proposes a novel design for a certification system that provides sufficient transparency and preserves privacy through selective disclosure of claims such that authorized parties can verify them. Moreover, unauthorized parties can also verify the correctness of the certification process without compromising privacy. We achieve this using an incremental Merkle tree of cryptographic commitments to users' credentials. The commitments are added to the tree based on verifying zero-knowledge issuance proofs. Users store credentials off-chain and can prove the ownership and authenticity of credentials without revealing their commitments. Further, our approach enables users to prove statements about the credentialâs claims in zero-knowledge. Our design offers a cost-efficient solution, reducing the amount of linkable on-chain data by up to 79% per credential compared to prior work, while maintaining transparency.
In this paper we present a new primitive for a key exchange protocol based on multivariate non-commutative polynomial rings, analogous to the classic Diffie-Hellman method. Our technique extends the proposed scheme of Boucher et al. from 2010. Their method was broken by Dubois and Kammerer in 2011, who exploited the Euclidean domain structure of the chosen ring. However, our proposal is immune against such attacks, without losing the advantages of non-commutative polynomial rings as outlined by Boucher et al. Moreover, our extension is not restricted to any particular ring, but is designed to allow users to readily choose from a large class of rings when applying the protocol. Our primitive can also be applied to other cryptographic paradigms. In particular, we develop a three-pass protocol, a public key cryptosystem, a digital signature scheme and a zero-knowledge proof protocol.
This work project analyses the possibility for a company to trade their goods and services for bitcoins, by joining the Bitcoin network. It analyses the technological and business requirements to join the Bitcoin Network by looking at Bitcoinâs potential to act as a mean of exchange for trade, unit of account and store of value. The analysis points to the motives, benefits and risks for investors to use the Bitcoin as a traditional currency and recommends on strategies for addressing those risks and maximizing benefits. Other than companies this report, to a lesser extent, will also analyse the Bitcoin from an investorâs point of view, this is, should an investor buy bitcoins for trade and make savings on a regular and everyday basis? A major finding in this work project is that companies could start using the Bitcoin system as a legit form of payment since the benefits of using this technology outweigh the costs and risks, given the right approach. This form of payment will contribute for the upgrade of a companyâs businessâ image, attract a new pool of consumers and businesses that already trade in bitcoins and pressure existing financial institutions and electronic payment vendors to upgrade their service levels.
Many algorithms admit very efficient batch versions that compute simultaneously the output of the algorithms on a set of inputs. Batch algorithms are widely used in cryptography, especially in the setting of pairing-based computations, where they deliver significant speed-ups. Auto Batch is an automated tool that computes highly optimized batch verification algorithms for pairing-based signature schemes. Thanks to finely tuned heuristics, Auto Batch is able to rediscover efficient batch verifiers for several signature schemes of interest, and in some cases to output batch verifiers that outperform the best known verifiers from the literature. However, Auto Batch only provides weak guarantees (in the form of a LaTeX proof) of the correctness of the batch algorithms it outputs. In this paper, we verify the correctness and security of these algorithms using the Easy Crypt framework. To achieve this goal, we define a domain-specific language to describe verification algorithms based on pairings and provide an efficient algorithm for checking (approximate) observational equivalence between expressions of this language. By translating the output of Auto Batch to this language and applying our verification procedure, we obtain machine-checked correctness proofs of the batch verifiers. Moreover, we formalize notions of security for batch verifiers and we provide a generic proof in Easy Crypt that batch verifiers satisfy a security property called screening, provided they are correct and the original signature is unforgeable against chosen-message attacks. We apply our techniques to several well-known pairing-based signature schemes from the literature, and to Groth-Sahai zero-knowledge proofs.
Melissa Chase, Markulf Kohlweiss, Anna Lysyanskaya, Sarah Meiklejohn
A signature scheme is malleable if, on input a message and a signature, it is possible to efficiently compute a signature on a related message, for a transformation that is allowed with respect to this signature scheme. In this paper, we first provide new definitions for malleable signatures that allow us to capture a broader range of transformations than was previously possible. We then give a generic construction based on malleable zero-knowledge proofs that allows us to construct malleable signatures for a wide range of transformation classes, with security properties that are stronger than those that have been achieved previously. Finally, we construct delegatable anonymous credentials from signatures that are malleable with respect to an appropriate class of transformations (that we show our malleable signature supports). The resulting instantiation satisfies a stronger security notion than previous schemes while also scaling linearly with the number of delegations.
2008 yilinda bir makale ile ortaya cikan, 2009 yilinda ilk islemini gerceklestiren bilgisayar algoritmalariyla tasarlanmis Bitcoin, son iki yilda onemli kullanici kitlesi yakalayarak, talebini artirmis, piyasa degerini hizla yukseltmis online bir satin alma birimi ya da sanal para olarak tanimlanabilir. Isminin gercekligi bile supheli anonim bir kisi tarafindan aktif hale getirilen sistemde bir devlet, merkez bankasi gibi klasik para birimlerinin sahip olduklari otoriteler ve garantorler yer almadigi gibi denetim de soz konusu degildir. Islemler network uzerinde direkt olarak iki taraf arasinda herhangi bir araci kurum olmaksizin gerceklestirildiginden maliyeti yok denecek kadar azdir. Sozkonusu durum herhangi bir devlet otoritesinin kontrol ve sorumlulugunun olmamasindan dogabilecek handikaplari da icinde barindirmaktadir. Bununla birlikte sistemin bircok disiplini bir araya getirerek calisan bir yapiya sahip olmasi disiplinlerarasi isbirligi ile ne gibi yeniliklerin ortaya cikabileceginin gorulmesi acisindan oneme sahiptir. Bu calismada; Bitcoinâin dogusu, ozellikleri, Dunyaâda ve Turkiyeâdeki gelisimi ve ekonomisi icindeki yeri, isleyis yontemi arastirilmis, yeni sanal para birimi ile ilgili mevcut durum analizi yapilmistir.
Bitcoin created as an academic article in 2008 and realized first transaction in 2009 is a digital/electronic currency which is designed on computer and built from calculating an algorithm. It developed rapidly and skyrocketed its market value in last two years by increasing its number of users and demand. The system designed by the pseudonymous person is not depend on neither any government nor a guarantor or an audit institution that the classical monetary system has. The transactions are realizing peer-to-peer network system and the cost of transaction is almost nothing. On the other hand Bitcoin inholds some of problems stemming from its uncontrollable features by any authority such as government, central banks etc. However the system which can be defined as a interdisciplinary study is a good sample in respect of digital innovations. In this study; emerge of Bitcoin, its features, place in World and Turkish economy, transaction methods are researched and worked on a SWOT analysis for new digital currency.
This paper analyzes correlations and causalities between Bitcoin market indicators and Twitter posts containing emotional signals on Bitcoin. Within a timeframe of 104 days (November 23rd 2013 - March 7th 2014), about 160,000 Twitter posts containing "bitcoin" and a positive, negative or uncertainty related term were collected and further analyzed. For instance, the terms "happy", "love", "fun", "good", "bad", "sad" and "unhappy" represent positive and negative emotional signals, while "hope", "fear" and "worry" are considered as indicators of uncertainty. The static (daily) Pearson correlation results show a significant positive correlation between emotional tweets and the close price, trading volume and intraday price spread of Bitcoin. However, a dynamic Granger causality analysis does not confirm a statistically significant effect of emotional Tweets on Bitcoin market values. To the contrary, the analyzed data shows that a higher Bitcoin trading volume Granger causes more signals of uncertainty within a 24 to 72-hour timeframe. This result leads to the interpretation that emotional sentiments rather mirror the market than that they make it predictable. Finally, the conclusion of this paper is that the microblogging platform Twitter is Bitcoin's virtual trading floor, emotionally reflecting its trading dynamics.
This paper presents an agent-based artificial cryptocurrency market in which heterogeneous agents buy or sell cryptocurrencies, in particular Bitcoins. In this market, there are two typologies of agents, Random Traders and Chartists, which interact with each other by trading Bitcoins. Each agent is initially endowed with a finite amount of crypto and/or fiat cash and issues buy and sell orders, according to her strategy and resources. The number of Bitcoins increases over time with a rate proportional to the real one, even if the mining process is not explicitly modelled. The model proposed is able to reproduce some of the real statistical properties of the price absolute returns observed in the Bitcoin real market. In particular, it is able to reproduce the autocorrelation of the absolute returns, and their cumulative distribution function. The simulator has been implemented using object-oriented technology, and could be considered a valid starting point to study and analyse the cryptocurrency market and its future evolutions.
Tujuan penelitian untuk mengetahui ada pengaruh pembelajaran ledger-line drills terhadap penguasaan gerak dasar lari sprint. Penelitian ini menggunakan metode kuasi eksperimen dengan desain Pretest-Postest Control Group Design. Adapun populasinya adalah seluruh siswa kelas VII SMP Negeri 1 Cibingbin, sedangkan sampel yang diambil menggunakan teknik purposif sampling diperoleh kelas 7 E dan 7 F, masing-masing sebanyak 23 siswa laki-laki dan perempuan, Instrument penelitian adalah lembar observasi test gerak dasar lari sprint, Hasil penelitian rata-rata pretest kontrol 70,60 kelas eksperimen 71,91. Rata-rata postest kontrol 76,13 dan rata-rata postest eksperimen 80,13 data postes tidak berdistribusi normal, sehingga analisis data menggunakan statistik nonparametrik yaitu dengan menggunakan uji Wilcoxon, diperoleh hasil Jhitung = 126 < Jtabel = 73 sehingga hipotesis diterima. Dapat disimpulkan bahwa ada pengaruh yang signifikan dari penerapan pembelajaran ledger-line drills terhadap penguasaan gerak dasar lari sprint. \nABSTRACT \nThe purpose of the study to know the effect of the ledger-line learning drills on mastering basic motion sprint. This study uses a quasi-experimental pretest-posttest design with control group design. The population is the entire class VII student of SMP Negeri 1 Cibingbin, \nwhereas samples taken using purposive sampling technique derived class 7 7 E and F, each as much as 23 boys and girls, is a research instrument observation sheet basic motion sprint test , Results of the study the average pretest control 70.60 71.91 experimental class. Average posttest control mean 76.13 and 80.13 posttest experimental posttest the data are not normally distributed, so the data using nonparametric statistical analysis by using the Wilcoxon test, the results obtained Jhitung = 126 <Jtabel = 73 so that the hypothesis is accepted. \nIt can be concluded that there is a significant effect of the application of the ledger-line learning to mastery of basic motion drills sprint.
In 1991, Indonesia began a process of decentralization in the health sector which had implications for the country's public hospitals. The public hospitals were given greater authority to manage their own personnel, finance and procurement, with which they were allowed to operate commercial sections in addition to offering public services. These public services are subsidized by the government, although patients still pay certain proportion of fees. The main objectives of health sector decentralization are to increase the ability of public hospitals to cover their costs and to reduce government subsidies. This study investigates the consequences of decentralization on cost recovery rate of public hospitals at district level. We examine five service units (inpatient, outpatient, operating room, laboratory and radiology) in three public hospitals. We find that after 20 years of decentralization, district hospitals still depend on government subsidies, demonstrated by the fact that the cost recovery rate of most service units is less than one. The commercial sections fail to play their role as revenue generator as they are still subsidized by the government. We also find that the bulk of costs are made up of staff salaries and incentives in all units except radiology. As this study constitutes exploratory research, further investigation is needed to find out the reasons behind these results.
<strong>Background</strong> Regional-based Integrated Healthcare Networks (IHNs) have been promoted in Brazil to overcome the fragmentation due to the health system decentralization to the municipal level; however, evaluations are scarce. The aim of this article is to analyse the content of IHN policies in force in Brazil, and the factors that influence policy implementation from the policymakersâ perspective. <strong>Methods</strong> A two-fold, exploratory and descriptive qualitative study was carried out based on (1) content analysis of policy documents selected to meet the following criteria: legislative documents dealing with regional-based IHNs; enacted by federal government; and in force, (2) semi-structured individual interviews were conducted to a theoretical sample of policymakers at federal (eight), state (five) and municipal levels (four). Final sample size was reached by saturation of information. An inductive thematic analysis was conducted. <strong>Results</strong> The results show difficulties in the implementation of IHN policies due to weaknesses that arise from the policy design and the performance of the three levels of government. There is a lack of specificity as to the criteria and tools for configuring and financing IHNs that need to be agreed upon between involved governments. For their part, policymakers emphasize the difficulty of establishing agreements in a health system with disincentives for collaboration between municipalities. The allocation of responsibilities that are too complex for the capacity and size of the municipalities, the abandonment of essential functions such as network planning by states and the strategic role by the Ministry, the âinvasionâ of competences among levels of government and high political turnover are also highlighted. <strong>Conclusions</strong> The implementation of regional-based IHN policy in Brazil is hampered by the decentralized organization of the health system to the municipal level, suggesting the need to centralize certain functions to regional structures or states and to define better the role of the government levels involved.
We study decentralized cryptocurrency protocols in which the participants do not deplete physical scarce resources. Such protocols commonly rely on Proof of Stake, i.e., on mechanisms that extend voting power to the stakeholders of the system. We offer analysis of existing protocols that have a substantial amount of popularity. We then present our novel pure Proof of Stake protocols, and argue that they help in mitigating problems that the existing protocols exhibit.
On February 2014, $650.000.000 worth of Bitcoins disappeared. Currently it is unclear whether hackers or MtGox, the largest Bitcoin exchange, are to be blamed. In either case, the anonymous and unregulated nature of the Bitcoin system makes it practically impossible for innocent victims to get their money back. We have investigated the technical possibilities, solutions and implications of introducing a regulatory framework based on redlisting Bitcoin accounts. Despite numerous proposals, the Bitcoin community has voiced a strong opinion against any form of regulation. However, most of the discussions were based on speculations rather than facts. We strive to contribute a scientific foundation to these discussions and illuminate the path to crypto-justice.
The financial crisis has led to a widespread loss of trust in financial intermediaries of all kinds, perhaps helping to open the way towards the general acceptance of alternative technologies. This paper briefly summarises the crypto-currency phenomenon, separating the âcurrencyâ issues from the potential technology benefits. With respect to crypto currencies, the paper argues that these canât undermine the ability of central banks to conduct monetary policy. They do, however, raise consumer protection and bank secrecy issues. The valuation of Bitcoins and price volatility issues are discussed, as well as electronic theft, contract failures, etc., all of which could result in large losses to users and hence ultimate costs to the taxpayer (e.g. the failure to provide adequate private pensions resulting in increased reliance on public pensions). The anonymity features of the crypto-currencies also facilitate tax evasion and money laundering, both of which are major public policy concerns. The technology associated with crypto-currencies, on the other hand, could ultimately shift the entire basis of trust involved in any financial transaction. It is an innovation that creates the ability to carry out transactions without the need for a trusted third party; i.e. a move towards trust-less transactions. This mechanism could work to eliminate the role of many intermediaries, thereby reducing transactions costs by introducing much needed competition to incumbent firms. The generic issues that policy makers need to examine are summarised.
In equal protection jurisprudence, courts adhere to a three-tiered system of review to determine the constitutionality of laws that rely on classifications of people. Strict scrutiny is the most searching inquiry, followed by intermediate scrutiny, and then rational basis. Rational basis review is the default. The two heightened levels of scrutiny apply to only a handful of already-identified groups. As a general principle, courts are deferential to the other branches of government. However, there is a departure to that principle when it comes to individual rights. That is, rational basis review is exceptionally deferential to the government. When individual rights are at stake, courts typically require the government to prove that its action is constitutional in nature and justified in fact. But under rational basis review, courts require the challenger of a law to disprove every conceivable, possible rationale for a law, regardless of whether it was actually a motivating factor behind the legislation. This standard has been interpreted to mean that even if a judge can imagine any reason why a rationale could â even hypothetically â justify a law, then the law stands as constitutional. Often governments do not even assert a rationale for their actions. Rather challengers must disprove even the wildest, most speculative and hypothetical justifications, which could include those introduced by the judge herself.This Article begins by revealing several of the inherent shortcomings of the current rational basis standard. That standard undermines principles of adversarial adjudication, destabilizes other individual rights doctrines, leaves the rights of certain citizens with virtually no protection, and legitimizes discriminatory animus. In effect, rational basis review preserves a discriminatory status quo, meaning that as societyâs values evolve, the Equal Protection Clause becomes less capable of protecting those values. Those troubling consequences need not persist. This Article proposes an alternative and improved in standard of review for the least intrusive level of judicial scrutiny in the tiered equal protection framework. This standard, which I call ârationale review,â shifts the burden of proof onto the government to show a reasonable, fact-based justification for laws that classify people. This standard would only marginally increase the burden on governments defending laws that involve classification of people, but it would require those governments to proffer at least an iota of evidence of a constitutionally permissible justification. Rationale review would not dramatically alter the current tiered equal protection framework. Those groups currently afforded heightened scrutiny would continue to receive such a standard of review. And laws concerning all other groups would continue to receive the least intrusive judicial inquiry under the tiered framework. Under rationale review, however, the government would bear the burden of proof in justifying as constitutional â with facts â those laws that make classifications of people.
Muhammad Hafidz Fazli Md Fauadi, Fairul Azni Jafar, Adi Saptari, Wan Ling Li
The increasingly challenging and dynamic nature of manufacturing industry has driven organizations to enhance their system efficiency. One of the most important aspects in manufacturing plant is the Material Transportation System (MTS). In order to address dynamic factors, MTS need to be equipped with rescheduling capability. This paper focuses on reactive transportation task assignment to a fleet of autonomous Automated Guided Vehicles (AGVs). This paper proposes a Mixed Integer Programming method to reschedule transportation tasks for a non-disruptive job shop manufacturing system based on Multi Agent System (MAS) architecture. The result shows that proposed rescheduling method is able to outperform conventional method significantly.
In recent years, the Semantic Web has become the focus of life science database development as a means to link life science data in an effective and efficient manner. In order for carbohydrate data to be applied to this new technology, there are two requirements for carbohydrate data representations: (1) a linear notation which can be used as a URI (Uniform Resource Identifier) if needed and (2) a unique notation such that any published glycan structure can be represented distinctively. This latter requirement includes the possible representation of nonstandard monosaccharide units as a part of the glycan structure, as well as compositions, repeating units, and ambiguous structures where linkages/linkage positions are unidentified. Therefore, we have developed the Web3 Unique Representation of Carbohydrate Structures (WURCS) as a new linear notation for representing carbohydrates for the Semantic Web.