Perfectly Oblivious (Parallel) RAM Revisited, and Improved Constructions

Oblivious RAM (ORAM) is a technique for compiling any RAM program to an oblivious counterpart, i.e., one whose access patterns do not leak information about the secret inputs. Similarly, Oblivious Parallel RAM (OPRAM) compiles a {\it parallel} RAM program to an oblivious counterpart. In this paper, we care about ORAM/OPRAM with {\it perfect security}, i.e., the access patterns must be {\it identically distributed} no matter what the program\u27s memory request sequence is. In the past, two types of perfect ORAMs/OPRAMs have been considered: constructions whose performance bounds hold {\it in expectation} (but may occasionally run more slowly); and constructions whose performance bounds hold {\it deterministically} (even though the algorithms themselves are randomized). In this paper, we revisit the performance metrics for perfect ORAM/OPRAM, and show novel constructions that achieve asymptotical improvements for all performance metrics. Our first result is a new perfectly secure OPRAM scheme with $O(\log^3 N/\log \log N)$ {\it expected} overhead. In comparison, prior literature has been stuck at $O(\log^3 N)$ for more than a decade. Next, we show how to construct a perfect ORAM with $O(\log^3 N/\log \log N)$ {\it deterministic} simulation overhead. We further show how to make the scheme parallel, resulting in an perfect OPRAM with $O(\log^4 N/\log \log N)$ {\it deterministic} simulation overhead. For perfect ORAMs/OPRAMs with deterministic performance bounds, our results achieve {\it subexponential} improvement over the state-of-the-art. Specifically, the best known prior scheme incurs more than $\sqrt{N}$ deterministic simulation overhead (Raskin and Simkin, Asiacrypt\u2719); moreover, their scheme works only for the sequential setting and is {\it not} amenable to parallelization. Finally, we additionally consider perfect ORAMs/OPRAMs whose performance bounds hold with high probability. For this new performance metric, we show new constructions whose simulation overhead is upper bounded by $O(\log^3 /\log\log N)$ except with negligible in $N$ probability, i.e., we prove high-probability performance bounds that match the expected bounds mentioned earlier

Small islands as ecotourism destinations : a Central Mediterranean perspective

A prerequisite for ecotourism development is the presence of natural environments, normally exhibited in protected areas, which serve as ecotourism venues. Little attention has been given to Mediterranean islands in terms of ecotourism. In this paper, nine islands in the central Mediterranean region were studied through a case study approach to investigate their potential as ecotourism destinations, taking into account the presence of protected areas and related aspects, including spatial dimensions and quality, to fulfil ecotourists. Larger islands with higher population densities were found to experience habitat fragmentation, and protected areas were thus in some cases relatively small and dispersed. In contrast, smaller, less populated islands were found to be more ideal ecotourism destinations due to limited anthropogenic impact and their capacity to fulfil the expectations of the ‘true specialists’, also known as ‘hard ecotourists’. Quality of ecotourism venues was found to affect ecotourist satisfaction. Ideal ecotourism sites on heavily impacted islands were found on the island periphery, in coastal and marine locations, with marine ecotourism serving as the ideal ecotourism product on such islands.peer-reviewe

Raziel: Private and Verifiable Smart Contracts on Blockchains

Raziel combines secure multi-party computation and proof-carrying code to provide privacy, correctness and verifiability guarantees for smart contracts on blockchains. Effectively solving DAO and Gyges attacks, this paper describes an implementation and presents examples to demonstrate its practical viability (e.g., private and verifiable crowdfundings and investment funds). Additionally, we show how to use Zero-Knowledge Proofs of Proofs (i.e., Proof-Carrying Code certificates) to prove the validity of smart contracts to third parties before their execution without revealing anything else. Finally, we show how miners could get rewarded for generating pre-processing data for secure multi-party computation.Comment: Support: cothority/ByzCoin/OmniLedge

Progress in Tourism Management: from the geography of tourism to geographies of tourism - A review

This Progress in Tourism Management paper seeks to review the development of geographical contributions to the study of tourism over the last decade. Given the limited number of surveys of geography published in academic journals since the 1970s, it is particularly timely to question and debate where the subject has evolved to, the current debates and issues facing those who work within the subject and where the subject will evolve in the next five years. The paper is structured around a number of distinct themes to emerge from the research activity of geographers, which is deliberately selective in its coverage due to the constraints of space, but focuses on: explaining spatialities; tourism planning and places; development and its discontents; tourism as an 'applied' area of research, and future prospects

Outcomes of a participatory approach to interpretive planning in the Shark Bay World Heritage area, Western Australia

This thesis examines a participatory approach to interpretive planning, employed in the Shark Bay World Heritage Area, Western Australia. At the project outset relations between the conservation agency responsible for administering World Heritage and the local community were strained, and complicated by a history of conflict over the World Heritage listing and subsequent management of the area. A participatory approach to interpretive planning was adopted in the hope that doing so would achieve the following: improved relations between polarised stakeholder groups, increased community support for the plan and its implementation, and improved access to the variety of knowledge pools within the Shark Bay community. Effectively ongoing and integrating the interests of the area\u27s polarised stakeholders meant that their social, political, organisational and disciplinary divisions had to be overcome. To do this, a novel participatory interpretive planning method was developed using action research. This method employed a combination of techniques, including a modified Delphi Technique based on indepth interviews, key informants, and direct prolonged emersion of the researcher in the community. The practical results of the project were the production of a stakeholder-derived communications strategy and interpretive plan for the World Heritage Area. These products embodied the collective social, cultural, economic and environmental interests of Shark Bay stakeholders, and included agreed-upon objectives, messages, stories for representing Shark Bar to the outside world. The participatory planning process also resulted in a number of instrumental and transformative outcomes including: surfacing of latent community issues, quieting of dominant rhetoric, identification of common values among stakeholders, collection of knowledge from multiple sources and contexts, equalisation of power between community segments, empowerment of marginalised community members, creation of social capital, and generation of support and commitment to plan implementation. In addition, the study demonstrated that participatory processes are vulnerable to cooption and manipulation by powerful stakeholders, and that the success of such processes relies more on the creation of trusting relationships (i.e. social capital) between stakeholders and facilitators than on the application of formulaic group techniques used to garner public input. With respect to interpretive planning, this project showed how a participatory approach to interpretive planning can be used as an ethical means to develop multiple narratives for interpretation that are just and legitimate representations of the community’s interests and stories. Other implications of this project, particularly in relation to the creation of social capital and horizontal and vertical relationships between community and agency groups, indicate that participatory interpretive planning can be used as an intervention in situations where conservation initiatives have resulted in conflict with local communities. Positive change is achieved through the creation of a common platform of values, mutual understanding and knowledge, from which further dialogue and reciprocal cooperation can take place. The evidence presented suggest that the stakeholder-centred approach to interpretive planning used in Shark Bay may form a useful basis for collaborative environmental management in a range of contexts and landscapes where new conservation initiatives are being contemplated. Lessons learned through application of this novel approach to interpretive planning may prove useful to interpretive professionals, environmental managers, governments and businesses attempting cross-disciplinary integration of multiple stakeholder interests

Moral Inquiry into Nordic Animal Work in Tourism: The Role of Emotions and Reasoning

Human-nonhuman animal relationship in tourism reveals a dichotomy between tourism prosperity and ethical concerns. For long nonhuman animals have been involved in different forms of tourism activities with functions ranging from entertainment and profit generation to marketing and education. At the same time, recent talks of animal rights and welfare call to ponder on the moral aspects of nonhuman animal involvement. The currently accelerating wave of social awareness of anthropogenic impacts on our globe’s ecosystems only further pushes both researchers and society to reassess human-nonhuman animal relationship within tourism. Within the field of tourism studies, human-nonhuman animal relationship has been predominantly researched from normative ethics perspectives and viewed either through the context of animal captivity or tourist-animal relationship, with little research taking the worker-animal relationship perspective. Theoretically, this study draws upon the normative discourse of academic literature and major animal ethics theories, joining a critical paradigm which highlights the need to shift the research focus away from justification or application of absolute normative principles towards the inquiry of morally problematic situations. It suggests a turn from a monistic viewpoint towards more intersubjective-interpretive approach. This study aims to explore how cognitive and emotional attributes of animal workers in Northern Europe facilitate moral deliberations of the use of nonhuman animals in tourism. After conducting participatory and non-participatory observations during winter period of 2019-2020, the empirical data was collected through semi-structured in-depth interviews with 6 tourism animal workers in Finnish Lapland in the winter period of 2020-2021. The data was then analysed through the qualitative interpretive content analysis to facilitate the exploratory disposition of the study. The empirical data of the study indicates that emotional motivations and emotional relationship with nonhuman animals facilitate moral positioning of nonhuman animal labour. At the same time, tourism animal workers utilize certain emotional management mechanisms to cope with the difficulties and specifics of the job. Overall, the results of the study on the theoretical level suggest reflective equilibrium as an approach to achieve an endpoint of moral inquiry

Development and change in the whale shark tourism industry at Ningaloo Marine Park, Western Australia

Popular demand for tourism experiences in the natural environment, and in particular for human-wildlife interactions, is increasing. Whale shark tourism at Ningaloo Marine Park on the North West Cape of Western Australia is one such wildlife interaction activity that has grown in popularity in recent years. From the late 1980s, when it was a little known specialist activity in a remote location, whale shark tourism has grown into an iconic tourism industry that now attracts up to 10,000 tourists seasonally. The research conducted for this thesis examined various aspects of the industry with a particular focus on the changes that have taken place over the course of the industry‘s development.To achieve this objective, data was primarily gathered through a series of participant questionnaires administered over several whale shark seasons. This information was integrated with content analyses of official documentation, tour operator feedback, and field observations. This elicited a rounded perspective of the industry which was contextualised using a theoretical framework for non-consumptive wildlife tourism devised by Duffus and DeardenThe growth in this tourism industry has been accompanied, over a relatively short period, by a shift in the nature of the participants. Originally specialist wildlife and nature based tourists exclusively focused on the opportunity to swim with whale sharks partook in the tours. Now a much wider cross section, sourced from the general tourist population in the region, wish to swim with the whale sharks. This shift in specialisation was also found to have decreased the amount expended in the region per capita. The specialised tourists, who originally dominated the industry, were significantly higher spenders; so much so that, despite the large increase in participant numbers, the total amount expended in the region by whale shark tourists has remained essentially unchanged.In addition to this focus on specialisation and expenditure other issues related to the implications of change in this industry over time were investigated. The main means by which tourists found out about the industry were informal marketing mechanisms such as word of mouth despite the industry being established for over a decade. Furthermore, even in such a remote tourism region, the major constraint on participating in whale shark tours remained financial.Finally changes in the licence conditions for operating the tours over time were researched through content analyses of the State government‘s expression of interest processes and responses from tour operators. This approach highlighted both the increasing regulatory demands and the commercial pressures experienced by the tour operators. This suggested that there is a delicate balance between the environmental and economic dimensions of regulation.Overall the insights gathered from the research revealed the consistently dynamic nature of this tourism system. The results also permitted some development and expansion of the wildlife tourism theory developed by Duffus and Dearden while in turn highlighting the usefulness of this framework in assisting in the management and planning of wildlife tourism industries