The need to protect our cultural heritage was stressed on revitalization of historical city centers in communities. The main aim of this research is to attract finance and activities to the historical city centers through the citizens and municipalities participation while cities expanded their boundaries toward suburban areas. Today the main problems which facing to the most historical city centers, is loss of their centrality through effect of urbanization on any point of the cities which is the most important issue on neglect and abandonment of the historical central area by decentralizing living, commerce and public areas. This article evaluate the ways in which city center revitalization can be effect on vitality and viability of the central area in case of Naghshe Jahan square which situated at the center of Isfahan city, Iran. Constructed between 1598 and 1629, it is now an important historical site, and one of UNESCO's World Heritage Sites.
Bitcoin was created in 2009 to serve as a virtual currency system outside the controls of the government or a central bank. Since then, both the cryptocurrency and the underlying blockchain technology have attracted significant attention worldwide. Several companies already accept payment for goods and services in Bitcoin, with the attraction being low processing costs and ease of use in cross-border transactions.
Can the parties to a conctract agree that the consideration should be paid in bitcoins? Or will this obligation be qualified as the delivery of 'objects'?
In the last 30 years several mathematical studies have been devoted to the
viscoelastic-gravitational coupling in stationary and transient regimes
either for static case or for hyperbolic case. However, to the best of our
knowledge there is a lack of mathematical study of the stabilization as $t$
goes to infinity of a viscoelastic-gravitational models crustal deformations
of multilayered Earth. Here we prove that, under some additional conditions
on the data, the difference of the viscoelastic and elastic solutions
converges to zero, as $t$ goes to infinity, in a suitable functional space.
The proof of that uses a reformulation of the hyperbolic/elliptic system in
terms of a nonlocal hyperbolic system.
In the past decades, the public procurement system in Kenya has undergone significant developments. From being a system with no regulations in the 1960s, and a system regulated by Treasury Circulars in the 1970s, 1980s and 1990s, the introduction of the PPDA Act of 2005 and the Procurement Regulations of 2006 has introduced new standards for public procurement in Kenya. Implementation of procurement process in public institutions has faced many hurdles and the levels of its performance have been wanting and this has been a concern to different stakeholders. Public procurement is a significant and yet understudied phenomenon. Thus, the study examined Public Procurement Process in Kenya: A Review of its Performance in the University of Nairobi, Kenya. Literature review focused on adaption of Procurement Act and regulations, types of tendering procedures, procurement plans and tendering committees in relation to performance. Design/Methodology/Approach: The study adopted a qualitative research design because it provided flexibility and afforded the researcher the opportunity to conduct an in-depth research. Case study on the procurement for AIBUMA conference was also done. A sample of 32 respondents was purposively selected from CHSS departments, Faculty, Schools Institutes, Centres and Procurement Management Unit from the UON. The finding shows that the majority of the respondents held the view that the Practice of Public Procurement Process in the University of Nairobi has been entrenched and there are structures in place to support the public procurement system but they face challenges. Over 11% of the respondents rated the performance of the procurement as below average and identified a number of challenges. The current legal framework provides for fully decentralized procurement process, leaving the full responsibility of undertaking procurement to the tender committee and the procurement unit at the level of CHSS public entity. There is indication that UON being a public entity is governed by the PPDA Act 2005, its attendant Regulations 2006 and instructions issued by the PPOA and for effective implementation the political good will is needed. The Procurement planning and its implementation in UON is more affected by the lack of cooperation between Procurement Management Unit and user department. It‘s evident that UON does not carry out market capability analysis in order to determine where to procure from and at what price. The study recommends UON should adhere to its service charter, procurement should be incorporated with the other aspects of functions within the organization, such as Finance, and human resources, execute the public procurement laws strictly and procurement staff be provided with training in order to improve their understanding and interpretation of the PPDA Act and Regulations. Perfect supervision and accountability mechanism, use of information technology to strengthen the supply side via E-procurement as it has a range of potential benefits for procurement processes. Finally, the study recommends a further research to be carried out in other procuring entities to find out if the same results can be obtained.
In this paper, a new notion which we call verifiably anonymous data collection protocol is introduced and formalized in the client-server model where each respondent uses a web interface to communicate with a server operated by the data miner. A construction leveraging a combination of semantically secure double trap-door encryption and OR zero-knowledge proof system is proposed and analyzed, where data sent from a respondent Alice is first encrypted using her personal partial key; Alice then proves to the data miner that the resulted ciphertext is valid and is sent by one of respondents dynamically formed by the respondent without getting the consent or assistance of the other respondents. A rigorous proof of the soundness and the zero-knowledge property of our data collection protocol in the presence of malicious adversary is presented.
Marilena Minou, George D. Stamoulis, George Thanos, Vikas Chandan
Demand Response (DR) programs constitute an efficient way to alleviate the problem of peak demand in smart grids. While the potential impact of DR can be significant, its success essentially depends on the participation and responsiveness of consumers. In this paper, we focus on the design of effective contract-based automated DR programs by energy providers that own supportive generators to meet excess demand and employ DR as a means to avoid their costly activation. We derive a theoretically justified formula for the amount of incentives that should be offered to a consumer to accept such a contract. Based on this, we introduce an algorithm for selecting the optimal set of consumers in terms of total incentives. This algorithm is employed under two different policies for restricting (in a different way) the discomfort caused to consumers. We evaluate these policies using real-world data and present interesting insights about the efficient selection of consumers to be targeted for DR and the total amount of incentives offered to them by the provider.
Mobile agent brings new concept on programming, especially on distributed computing paradigm. It attracts great interest because of its mobility, autonomy and persistence. But it also brings security issues i.e. insecure networks, malicious agents, malicious hosts and malicious users. One most difficult issues is protecting mobile agent from malicious host because mobile agent execute its code on host so that host can do many things to manipulate data, code and control flow of mobile agent. This paper proposes mobile-agent's self-reliant host security examination so that mobile agent is able to identify malicious host. In this proposed scheme, every hosts must have signature in blinded form in order to ensure unauthorized host cannot use this signature. This signature serves to distinguish malicious hosts with trusted host. When mobile agent arrives at new host, it will check validation of host's signature. Mobile agent also gives challenge to host, and host has to give a valid response. If host cannot give valid signature and response, mobile agent will identify this host as malicious host and return to its previous host. Zero knowledge proof of knowledge is used on challenge-response phase so that private keys cannot be revealed.
The potential synergies between consumer handheld devices, particularly smartphones and biometric technologies is outlines. The practicalities and challenges for three such technologies - fingerprint, iris and palmprint - are presented. The use of biometrics for personal authentication is discussed, including the use of zero knowledge proof techniques to ensure that the biometric data does not leave the phone. The scope for data theft and breach through spoofing of the original biometric are discussed. Finally the potential impact of this technology synergy on personal privacy is considered.
With the implementation of devolution in Kenya where county governments are responsible for development projects in decentralized regions in Kenya, urban infrastructure projects and their financing mode is of importance in academic discussions, government policies and public sector financial management. Various county governments have initiated PPP projects for infrastructure development to suffice their mandate; however, there is scanty academic information on the factors that determine the success of attracting funding for such projects as well as the factors for the success of the projects themselves. The constraints identified to hinder the success include financial constraints, government constraints and economic constraints. This descriptive study therefore sought to establish the determinants of success of urban infrastructure projects financed by public private parternerships in Kenyan counties. Primary data was collected using a semistructured questionnaire targeting 47 county employees responsible for PPP projects implementation. 41 questionnaires were returned providing a response rate of 87.23%. The study finds that all the counties have PPP units which is in line with the national governments initiative to encourage PPP funding for projects for improving infrastructure levels across the counties. It also found that 70.73% of the counties have in place PPP implementation guidelines which are instrumental in guiding the process. The study finds that 26.2 % of variations in the proportion of urban infrastructure projects funded within the PPP framework are explained by changes in macro economic conditions, government guarantees, project implementability and procurement process. The findings show a statistically significant positive relationship between government guarantess and success of the projects. There is also a statistically significant negative relationship between macro-economic conditions and success of the projects. The study also notes a positive relationship between project implementability and sucess as well as a negative relatioship between procurement process and project success. The relationships are not statistically significant. The study recommends that government should support infrastructural development by providing project guarantees and ensuring the macro-economic environment is sound for private investments. Further, counties should address the concerns on procurement transparency and they should enhance their capacity for project feasibility inquiries, design and implementation. The study recommends further investigations on why various proposed projects are not financed and the studies should consider the other possible control variables outside the scope of the current study that may explain the variations in the success of the projects
This article attempts to capture the power developed in an area aftermath of reformation era in 1998 marked by implementing autonomous region or decentralized. Power in The New Order Regime, that was The Centralistic changed with the emergence of the local political elite that affirming their power by various sources of capital. By having a more open space for local figures to snatch the seat of power at the local level in the county, political competition then became closer in social community base level. Those who have a culture of social capital, networks and other social networking might be easier to perform. No exception figure of “Kiai” head of Islamiccommunity originating from habitus religious activities and education in boarding school and other community social activities. In Bangkalan regency Habitus-based Political Elite Kiai boils down to descendants of the BaniKholildiasporic in various organizations either initiating Community-Social Organizations, political parties and legislative Institutions and Executive. The method used in this research is descriptive-qualitative structure of Agency Bourdieu's approach with data mining using in-depth interviews and technical documentation. The end result of this thesis was to see that the political and Dynastic Politics Breeds successfully built by RKH Fuad Amin during his leadership in two periods, ten years later continued by the winning of his son MakmunIbnuFuad with a majority of votes 93,47 percent. After his main rival who is also a descendant of BaniKholil, namely KH Imam BuchoriKholil failed to follow the contestation elections directly. In contestation elections in Bangkalan Regency, the ability of the group or Political Actor in using sources of capital and symbolic power in a society is still very effective in managing their Paternalistic room practices.In the analysis of Structure-Agency Bourdieu's perspective, social space and social groups who control it are the products of a historical struggle continuously updated for contested or won as well as establish dominance in power.
Bitcoin is defined as digital money within a decentralized peer-to-peer payment network. It is a hybrid between fiat currency and commodity currency without intrinsic value and independent of any government or monetary authority. This paper analyses the question of whether bitcoin is a currency or an asset and, more specifically, what is its current usage and what usage will prevail in the future, given its characteristics? We analyse the statistical properties of bitcoin and find that it is essentially uncorrelated with traditional asset classes such as stocks, bonds and commodities, both in normal times and in periods of financial turmoil. The analysis of transaction data of bitcoin accounts shows that bitcoins are mainly used as a speculative investment and not as an alternative currency and medium of exchange. Bitcoin is still small relative to the size of other asset classes and, thus, does not pose an immediate risk for monetary, financial or economic stability.
Multiplicative complexity is a complexity measure defined as the minimum number of AND gates required to implement a given primitive by a circuit over the basis (AND, XOR, NOT). Implementations of ciphers with a small number of AND gates are preferred in protocols for fully homomorphic encryption, multi-party computation and zero-knowledge proofs. In 2002, Fischer and Peralta [12] showed that the number of n-variable Boolean functions with multiplicative complexity one equals 2 ( 2 3 ) . In this paper, we study Boolean functions with multiplicative complexity 2. By characterizing the structure of these functions in terms of affine equivalence relations, we provide a closed form formula for the number of Boolean functions with multiplicative complexity 2.
We introduce LOCATHE (Location-Enhanced Authenticated Key Exchange), a generic protocol that pools location, user attributes, access policy and desired services into a multi-factor authentication, allowing two peers to establish a secure, encrypted session and perform mutual authentication with pre-shared keys, passwords and other authentication factors. LOCATHE contributes to: (1) forward secrecy through ephemeral session keys; (2) security through zero-knowledge password proofs (ZKPP), such that no passwords can be learned from the exchange; (3) the ability to use not only location, but also multiple authentication factors from a user to a service; (4) providing a two-tiered privacy authentication scheme, in which a user may be authenticated either based on her attributes (hiding her unique identification), or with a full individual authentication; (5) employing the expressiveness and flexibility of Decentralized or Multi-Authority Ciphertext-Policy Attribute-Based Encryption, allowing multiple service providers to control their respective key generation and attributes.
The Bitcoin system is an anonymous, decentralized crypto-currency. There are some deanonymizating techniques to cluster Bitcoin addresses and to map them to users' identifications in the two research directions of Analysis of Transaction Chain (ATC) and Analysis of Bitcoin Protocol and Network (ABPN). Nowadays, there are also some anonymization methods such as coin-mixing and transaction remote release (TRR) to cover the relationship between Bitcoin address and the user. This paper studies anonymization and de-anonymization technologies and proposes some directions for further research.
Giuseppe Di Battista, Valentino Di Donato, Maurizio Patrignani, Maurizio Pizzonia · 6 authors
Bitcoin is a digital currency whose transactions are stored into a public ledger, called blockchain, that can be viewed as a directed graph with more than 70 million nodes, where each node represents a transaction and each edge represents Bitcoins flowing from one transaction to another one. We describe a system for the visual analysis of how and when a flow of Bitcoins mixes with other flows in the transaction graph. Such a system relies on high-level metaphors for the representation of the graph and the size and characteristics of transactions, allowing for high level analysis of big portions of it.
In recent years, global governance institutions have operationalized their commitment to the right to health by advocating for universal health coverage (UHC) – particularly in the Global South. UHC aims to develop health systems that are efficient, well staffed, and capable of providing affordable and appropriate medical care and essential medicines to rich and poor alike (World Health Organisation, 2014). The political priority afforded to this goal is driven by an acknowledgement that people in wealthy and poor countries alike are priced out of the “market” for health care. This has caused concern because of the negative economic effects associated with inadequate access to care. Academic research and scholarly rhetoric often justifies UHC on the grounds that it will strengthen the economic position of households (particularly households living below or just above the poverty line) and contributes to the growth prospects of national economies (World Health Organisation Commission on Macroeconomics and Health, n.d.). UHC is thus framed as an investment in human capital: Healthier citizens are more productive citizens. They are more capable of investing in their own well-being, and that of their dependents, through participation in the labor market rather than relying on public assistance. Why is it problematic to justify UHC, and health promotion more generally, on the basis of its economic value, that is, on the basis of the contributions it makes to growing markets and improving economic productivity? Research on the reconfiguration of welfare regimes in the Global North suggests that globalization is undermining their social, political, and economic foundations. These countries – much like their counterparts in the Global South – are experiencing a rise in unemployment, coupled with an increase in flexible and precarious work. Globalization has also been associated with an increase in human migration from the Global South to the Global North and within the Global South. As a result, states are simultaneously faced with increased demands for welfare from the unemployed and the working poor, an erosion of their tax base, and increasingly heterogeneous societies. States are responding to these changes by adopting welfare policies that expand the influence of market actors and market logics on social welfare. Consequently, decisions about how to define and promote the public good are increasingly made in a decentralized fashion by private actors operating in households or markets rather than in democratic political institutions. For example, in many countries, access to public assistance is now contingent on welfare recipients' efforts to find employment (i.e., the shift from welfare to “workfare”) and pay for basic services, on private and public sector providers' ability to provide social services efficiently and cost effectively, and on the state's ability to efficiently coordinate interactions between citizen consumers and social services providers (Roche, 2002). Advocacy for UHC reflects these political and normative shifts. It de-emphasizes the importance of collective democratic decision-making about how the health needs of populations should be addressed. Instead, public institutions are primarily responsible for solving a “technical” problem: financing health consumption for all. As public institutions become more focused on policing health financing, they reduce the services they provide and, in so doing, strengthen the market power of private players (Global Health Watch, 2014). Private actors – philanthropic foundations and for-profit providers of medical services, health insurance, and medicines – now routinely constrain the ability of governments to decide the terms on which the right to health should be advanced. Their influence is legitimated by the World Bank and IMF austerity policies that frame debt repayment and economic growth as the direct and primary responsibilities of democratic governments. Although governments in the Global South are particularly vulnerable to these pressures, similar pressures are present in the Global North – as demonstrated by private sector opposition to Obamacare (Kirsch, 2013) and patent law reform in South Africa (De Wet, 2014). In contrast, these institutions frame the obligation to promote the social dimension of citizenship as something that can be outsourced to private actors and/or achieved through market logics. Additionally, the value of social policies is often justified in economic terms, for example, in terms of their ability to improve the productivity of worker citizens and the revenues of public and private sector service providers. This discourse de-emphasizes the intrinsic value of formal and substantive equality and meaningful participation in collective decision-making about the public good. Political institutions feature in it primarily as mechanisms that mediate the efficacy of investments in health care. Their significance is determined by their ability to maximize returns on investments in health (Jack and Lewis, 2009). What are some of the consequences of advancing the right to health in this manner? Research shows that the shift from universalistic welfare regimes to regimes that target “especially vulnerable” or “especially deserving” populations undermines social solidarity by stigmatizing welfare recipients as people who violate the liberal ethos of contemporary welfare states. Vulnerable populations (e.g., non-citizens, people of color, indigenous peoples, working class women, and able-bodied unemployed people) are stigmatized as being reluctant to (or incapable of) succeeding in market societies on their own “merit” and as unfairly benefiting from welfare policies that advance their particularistic group interests rather than overall well-being (Brown, 2003). The low social status of these groups obstructs their ability to access appropriate and effective medical care, even when it is available at no or little cost to patients (Bassett, 2015). Globalization is a politically and socially mediated process. The harmful effects of globalization on social inclusion, and the limits of the policy responses to these dynamics, point to the urgent need for collective action and research aimed at addressing the dimensions of globalization that undermine the social determinants of health by privatizing, stigmatizing, and instrumentalizing the management of health – and in some cases, life itself. Collective action is needed to democratize decision-making about health care at the local, national, and global levels in a meaningful way to foster social solidarity and address status inequalities that lead to disproportionate rates of illness and death among stigmatized social groups and to politicize the priority placed on economic growth, given its sometimes harmful effects on human and planetary health. Global Challenges is a journal that welcomes scholarly contributions on these tough issues and insightful commentary that points toward strategies for addressing them.