Security and Trust in P2P Systems

2011 ◽  
pp. 145-165 ◽  
Author(s):  
Michael Bursell
Keyword(s):  
Social Contexts ◽  
Peer To Peer ◽  
Future Research ◽  
P2p Systems ◽  
Trade Offs ◽  
Technical Systems ◽  
Current Systems

This chapter examines the issue of security in peer-to-peer (P2P) systems from the standpoint of trust. It takes the view that P2P systems present particular challenges in terms of trust over other socio-technical systems, and identifies three key areas of importance: identity; social contexts; punishment and deterrence. It suggests that a better understanding of these areas and the trade-offs associated with them can help in the design, implementation, and running of P2P systems. The chapter combines a discussion of problems and issues in current systems with a review of some of the wider sociological and nonsystems literature which can aid those involved with P2P systems. It concludes with some suggestions for areas where future research may provide fruitful insights.

Security and Trust in P2P Systems

2008 ◽  
pp. 1488-1503
Author(s):  
Michael Bursell
Keyword(s):  
Social Contexts ◽  
Peer To Peer ◽  
Future Research ◽  
P2p Systems ◽  
Trade Offs ◽  
Technical Systems ◽  
Current Systems

This chapter examines the issue of security in peer-to-peer (P2P) systems from the standpoint of trust. It takes the view that P2P systems present particular challenges in terms of trust over other socio-technical systems, and identifies three key areas of importance: identity; social contexts; punishment and deterrence. It suggests that a better understanding of these areas and the trade-offs associated with them can help in the design, implementation, and running of P2P systems. The chapter combines a discussion of problems and issues in current systems with a review of some of the wider sociological and nonsystems literature which can aid those involved with P2P systems. It concludes with some suggestions for areas where future research may provide fruitful insights.

scholarly journals Immune function during pregnancy varies between ecologically distinct populations

2020 ◽  
Vol 2020 (1) ◽  
pp. 114-128
Author(s):  
Carmen Hové ◽  
Benjamin C Trumble ◽  
Amy S Anderson ◽  
Jonathan Stieglitz ◽  
Hillard Kaplan ◽  
...  
Keyword(s):  
Leukocyte Count ◽  
Total Leukocyte Count ◽  
Future Research ◽  
Differential Leukocyte Count ◽  
Ecological Conditions ◽  
Trade Offs ◽  
The Usa ◽  
Immunological Changes ◽  
Fetal Antigens ◽  
Pathogen Exposure

Abstract Background and objectives Among placental mammals, females undergo immunological shifts during pregnancy to accommodate the fetus (i.e. fetal tolerance). Fetal tolerance has primarily been characterized within post-industrial populations experiencing evolutionarily novel conditions (e.g. reduced pathogen exposure), which may shape maternal response to fetal antigens. This study investigates how ecological conditions affect maternal immune status during pregnancy by comparing the direction and magnitude of immunological changes associated with each trimester among the Tsimane (a subsistence population subjected to high pathogen load) and women in the USA. Methodology Data from the Tsimane Health and Life History Project (N = 935) and the National Health and Nutrition Examination Survey (N = 1395) were used to estimate population-specific effects of trimester on differential leukocyte count and C-reactive protein (CRP), a marker of systemic inflammation. Results In both populations, pregnancy was associated with increased neutrophil prevalence, reduced lymphocyte and eosinophil count and elevated CRP. Compared to their US counterparts, pregnant Tsimane women exhibited elevated lymphocyte and eosinophil counts, fewer neutrophils and monocytes and lower CRP. Total leukocyte count remained high and unchanged among pregnant Tsimane women while pregnant US women exhibited substantially elevated counts, resulting in overlapping leukocyte prevalence among all third-trimester individuals. Conclusions and implications Our findings indicate that ecological conditions shape non-pregnant immune baselines and the magnitude of immunological shifts during pregnancy via developmental constraints and current trade-offs. Future research should investigate how such flexibility impacts maternal health and disease susceptibility, particularly the degree to which chronic pathogen exposure might dampen inflammatory response to fetal antigens. Lay Summary This study compares immunological changes associated with pregnancy between the Tsimane (an Amazonian subsistence population) and individuals in the USA. Results suggest that while pregnancy enhances non-specific defenses and dampens both antigen-specific immunity and parasite/allergy response, ecological conditions strongly influence immune baselines and the magnitude of shifts during gestation.

scholarly journals Selective Harvesting Robotics: Current Research, Trends, and Future Directions

2021 ◽  
Author(s):  
Gert Kootstra ◽  
Xin Wang ◽  
Pieter M. Blok ◽  
Jochen Hemming ◽  
Eldert van Henten
Keyword(s):  
Review Paper ◽  
Production Systems ◽  
Future Research ◽  
Limiting Factor ◽  
Future Directions ◽  
Research Directions ◽  
Selective Harvesting ◽  
Important Solution ◽  
Future Research Directions ◽  
Current Systems

Abstract Purpose of Review The world-wide demand for agricultural products is rapidly growing. However, despite the growing population, labor shortage becomes a limiting factor for agricultural production. Further automation of agriculture is an important solution to tackle these challenges. Recent Findings Selective harvesting of high-value crops, such as apples, tomatoes, and broccoli, is currently mainly performed by humans, rendering it one of the most labor-intensive and expensive agricultural tasks. This explains the large interest in the development of selective harvesting robots. Selective harvesting, however, is a challenging task for a robot, due to the high levels of variation and incomplete information, as well as safety. Summary This review paper provides an overview of the state of the art in selective harvesting robotics in three different production systems; greenhouse, orchard, and open field. The limitations of current systems are discussed, and future research directions are proposed.

Navigating NGO–Government Relations in Human Rights: New Archival Evidence from Amnesty International, 1961–1986

2021 ◽  
Author(s):  
Swati Srivastava
Keyword(s):  
Human Rights ◽  
Oral History ◽  
Social History ◽  
Future Research ◽  
International Institute ◽  
Strategic Choices ◽  
Small Individual ◽  
Amnesty International ◽  
Government Relations ◽  
Trade Offs

Abstract This research note unveils new archival evidence from Amnesty International's first twenty-five years (1961–1986) to shed light on the realization of international human rights as Amnesty balanced “nonpolitical politics” through multifaceted government relations. The research draws from minutes and reports of eighty meetings of Amnesty's executive leadership and interviews from the 1983 to 1985 Amnesty Oral History project, all collected from the International Institute of Social History. The records show that during this time Amnesty relied on government and foundation funding to exit a severe financial crisis. Amnesty also cultivated a private diplomatic network with governments for access and advocacy and conducted side bargains with closed countries for access and reforms. In one sense, the new evidence complicates the conventional wisdom that Amnesty was only financed from small, individual donors and stayed away from private government dealings. In another sense, the new data extend existing insights about INGO strategic action by revealing Amnesty's pragmatic trade-offs when maintaining arms–length relations with governments to better appreciate the organization's early challenges and accomplishments. The note ultimately contributes to scholarship on the strategic choices of INGOs and provides new data for future research on the agency of nonstate actors in global governance navigating complex government relations. Esta nota de investigación presenta nueva evidencia documental de los primeros 25 años de Amnistía Internacional (Amnesty International), de 1961 a 1986, para arrojar luz sobre el cumplimiento de las normas internacionales de derechos humanos mientras Amnistía balanceaba la “política no política” mediante relaciones gubernamentales polifacéticas. La investigación incorpora actas e informes de 80 reuniones del liderazgo ejecutivo de Amnistía y entrevistas de 1983 a 1985 del proyecto Historia Oral de Amnistía (Amnesty Oral History), recopiladas del Instituto Internacional de Historia Social. Los documentos muestran que, en ese momento, Amnistía necesitó financiación gubernamental y de fundaciones para salir de una crisis financiera grave. Amnistía también cultivó una red diplomática privada con gobiernos a cambio de acceso y defensa, y tuvo negocios paralelos con países cerrados a cambio de acceso y reformas. En un sentido, la nueva evidencia complica la sabiduría convencional de que Amnistía solo tuvo financiamiento de donantes pequeños e individuos y se mantuvo lejos de los negocios privados con gobiernos. En contraste, los nuevos datos amplían las percepciones existentes sobre la acción estratégica de organizaciones no gubernamentales internacionales (ONGI), revelando las concesiones pragmáticas de Amnistía al mantener relaciones independientes con gobiernos, y permiten apreciar mejor los desafíos y logros iniciales de la organización. La nota, fundamentalmente, contribuye a la investigación sobre las decisiones estratégicas de las ONGI y brinda nuevos datos para futuras investigaciones sobre la autonomía de los actores no estatales que navegan relaciones gubernamentales complejas en la gobernanza global. Cet exposé de recherche dévoile de nouvelles preuves issues des 25 premières années d'archives d'Amnesty International (1961–1986) pour apporter un éclairage sur l'application des droits de l'Homme tandis qu'Amnesty équilibrait la « politique apolitique » par le biais de relations gouvernementales à plusieurs facettes. Cette recherche s'appuie sur des minutes et rapports de 80 réunions de la haute direction d'Amnesty, ainsi que sur des entretiens qui ont eu lieu entre 1983 et 1985 dans le cadre du projet Oral History (Histoire orale) d'Amnesty. Ces données ont toutes été recueillies auprès de l'Institut International d'Histoire Sociale. Les archives montrent que durant cette période, Amnesty a dû compter sur le financement de gouvernements et de fondations pour sortir d'une grave crise financière. Amnesty a également cultivé un réseau diplomatique privé avec des gouvernements pour faciliter son accès et son plaidoyer dans le pays concerné tout en menant des négociations parallèles avec les pays fermés pour y favoriser son accès et les réformes. En un sens, les nouvelles preuves compliquent les idées reçues selon lesquelles Amnesty ne serait financée que par de petits donateurs individuels et resterait à l’écart des affaires gouvernementales privées. Mais en un autre sens, ces nouvelles données enrichissent les renseignements existants sur l'action stratégique des organisations non gouvernementales internationales en révélant qu'Amnesty s’était livrée à des compromis pragmatiques en entretenant des relations avec les gouvernements tout en restant à distance. Ces renseignements nous permettent donc de mieux apprécier les premiers défis et accomplissements de l'organisation. En définitive, cet exposé contribue aux études sur les choix stratégiques des organisations non gouvernementales internationales et fournit de nouvelles données pour les recherches futures sur l'intervention des acteurs non étatiques dans la gouvernance mondiale tandis qu'ils naviguent dans des relations gouvernementales complexes.

scholarly journals Resource-Aware Cooperative Caching on Mobile Ad-hoc Peer to Peer Networks

2021 ◽  
Author(s):  
Hoda R.K. Nejad
Keyword(s):  
Ad Hoc Networks ◽  
Overlay Networks ◽  
Ad Hoc ◽  
Data Access ◽  
Peer To Peer ◽  
Data Availability ◽  
Cooperative Caching ◽  
P2p Systems ◽  
Hoc Networks ◽  
Resource Aware

With the emergence of wireless devices, service delivery for ad-hoc networks has started to attract a lot of attention recently. Ad-hoc networks provide an attractive solution for networking in the situations where network infrastructure or service subscription is not available. We believe that overlay networks, particularly peer-to-peer (P2P) systems, is a good abstraction for application design and deployment over ad-hoc networks. The principal benefit of this approach is that application states are only maintained by the nodes involved in the application execution and all other nodes only perform networking related functions. On the other hand, data access applications in Ad-hoc networks suffer from restricted resources. In this thesis, we explore how to use Cooperative Caching to improve data access efficiency in Ad-hoc network. We propose a Resource-Aware Cooperative Caching P2P system (RACC) for data access applications in Ad-hoc networks. The objective is to improve data availability by considering energy of each node, demand and supply of network. We evaluated and compared the performance of RACC with Simple Cache, CachePath and CacheData schemes. Our simulation results show that RACC improves the lay of query as well as energy usage of the network as compared to Simple Cache, CachePath and CacheData.

scholarly journals Going Behind the Scenes at Teacher Colleges: Online Student Knowledge Sharing through Social Network Technologies

10.28945/3863 ◽  
2017 ◽  
Vol 13 ◽  
pp. 167-184 ◽  
Author(s):  
Smadar Bar-Tal ◽  
Christa S. C. Asterhan
Keyword(s):  
Higher Education ◽  
Social Network ◽  
Adult Students ◽  
Knowledge Sharing ◽  
Peer To Peer ◽  
Future Research ◽  
Teaching Staff ◽  
Central Feature ◽  
College Life ◽  
Teacher Colleges

Aim/Purpose: The present study aims to describe existing peer-to-peer, social network-based sharing practices among adult students in teacher colleges. Background: Ubiquitous social network sites open up a wide array of possibilities for peer-to-peer information and knowledge sharing. College instructors are often unaware of such practices that happen behind the scenes. Methodology: An interpretative, qualitative research methodology was used. Thirty-seven Israeli students at a teacher college in Israel participated in either focus group discussions of (N = 29) or in-depth interviews (N = 8). Contribution: Whereas knowledge sharing has been a main focus of research in organizational and information sciences, its relevance to educational settings has thus far been underscored. Recent research shows that peer–to-peer knowledge sharing is wide-spread among teenage students. The current study extends that work to an adult student population. Findings: The findings show that knowledge sharing of this type is a common and even central feature of students’ college life and study behavior. It takes place through a variety of small and larger social network-based peer groups of different formations, including mostly college students but at time also practicing, experienced teachers. Sharing groups are formed on the spot for short term purposes or are stable, continuous over longer time periods. The contents shared are predominantly lesson summaries, material for exams, reading summaries, and lesson plans. They are used immediately or stored for future use, as students have access to vast data bases of stored materials that have been compiled throughout the years by students of previous cohorts. Teacher students mentioned a range of reasons for sharing, and overall regard it very positive. However, some downsides were also acknowledged (i.e., superficial learning, exclusion, attentional overload, and interruptions). Recommendations for Practitioners: College faculty and teaching staff should be cognizant and informed about these widespread peer-based knowledge sharing practices and consider whether perhaps changes in teaching formats and task assignments are required as a result. Future Research: Future research should extend this work to other higher education settings, cultures and countries, and should map the perceptions of higher education teaching staff about peer-to-peer, online knowledge sharing.

Attitudes and behaviour towards organic products: an exploratory study

2008 ◽  
Vol 36 (2) ◽  
pp. 158-175 ◽  
Author(s):  
Efthimia Tsakiridou ◽  
Christina Boutsouki ◽  
Yorgos Zotos ◽  
Kostantinos Mattas
Keyword(s):  
Organic Food ◽  
Food Products ◽  
Local Economy ◽  
Health Concern ◽  
Future Research ◽  
Consumer Decision Making ◽  
Content Type ◽  
Actual Behaviour ◽  
Trade Offs ◽  
Organic Products

PurposeThe aim of this paper is to identify consumers' attitudes and behaviour towards organic products in Greece.Design/methodology/approachThis paper draws on a non‐probability quota sample of 660 respondents to explore the attitudes and behaviour of Greek consumers towards organic food products.FindingsGreek consumers seem to be informed about environmental and health issues. They seek information about the nutritional value of food and demand more products free from chemical residues. The results show that most consumers associate organic consumption mainly with fruit and vegetables. Although demographics seem to affect attitudes towards organics, their value in explaining actual behaviour is minimal.Research limitations/implicationsIt is recognized that the data gathered in this study focus on the metropolitan area of Thessaloniki, Greece. The specific area though, is considered to be representative of the total Greek population. The results confirm that health, concern for the environment, animal welfare and support of the local economy are drivers of organic consumption. However, there is an indication that the importance of motives and barriers may vary for different product categories and perhaps future research should focus on product segmentation.Practical implicationsAlthough certain similarities in consumers' attitudes towards organic food products have been identified, this paper records the variation in behaviour towards organics among the various consumer groups examined in Greece, and highlights the gap between attitudes and actual behaviour. Given the complexity of consumer decision making, future research should explore the other value trade‐offs that consumers make.Originality/valueThis paper attempts to provide evidence on the relatively under researched area of organics attitudes and behaviour in Greece.

A systematic review of the literature on supply chain agility

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bharat Singh Patel ◽  
Murali Sambasivan
Keyword(s):  
Supply Chain ◽  
Cost Benefit ◽  
Business Environment ◽  
Future Research ◽  
Research Directions ◽  
Content Type ◽  
Trade Offs ◽  
Supply Chain Agility ◽  
Agility Assessment ◽  
Future Research Directions

Purpose The purpose of this study is to critically examine the scholarly articles associated Murali Sambasivan with the diverse aspects of supply chain agility (SCA). The review highlights research insights, existing gaps and future research directions that can help academicians and practitioners gain a comprehensive understanding of SCA. Design/methodology/approach The present study has adopted author co-citation analysis as the research methodology, with a view to thoroughly investigating the good-quality articles related to SCA that have been published over a period of 22 years (1999-2020). In this study, 126 research papers on SCA – featuring diverse aspects of agility – from various reputed journals have been examined, analysed and assimilated. Findings The salient findings of this research are, namely, agility is different from other similar concepts, such as flexibility, leanness, adaptability and resilience; of the 13 dimensions of agility discussed in the literature, the prominent ones are quickness, responsiveness, competency and flexibility; literature related to SCA can be categorised as related to modelling the enablers, agility assessment, agility implementation, leagility and agility maximisation. This research proposes a more practical definition and framework for SCA. The probable areas for future research are, namely, impediments to agility, effective approaches to agility assessment, cost-benefit trade-offs to be considered whilst implementing agility, empirical research to validate the framework and SCA in the domain of healthcare and disaster relief supply chains. Practical implications This paper provides substantial insights to practitioners who primarily focus on measuring and implementing agility in the supply chain. The findings of this study will help the supply chain manager gain a better idea about how to become competitive in today’s dynamic and turbulent business environment. Originality/value The originality of this study is in: comprehensively identifying the various issues related to SCA, such as related concepts, definitions, dimensions and different categories of studies covered in literature, proposing a new definition and framework for SCA and identifying potential areas for future research, to provide deeper insights into the subject and highlight areas for future research.

WHY DO INSECTS EVOLVE IMMUNE PRIMING? A SEARCH FOR CROSSROADS

2021 ◽  
Author(s):  
Arun Prakash ◽  
imroze khan
Keyword(s):  
Immune Responses ◽  
Low Dose ◽  
Immune Memory ◽  
Comparative Approach ◽  
Future Research ◽  
Subsequent Infection ◽  
Immune Priming ◽  
Trade Offs ◽  
Evolutionary Response ◽  
Basal Immunity

Until recently, it was assumed that insects lack immune memory since they do not have vertebrate-like specialized memory cells. Therefore, their most well studied evolutionary response against pathogens was increased basal immunity. However, growing evidence suggests that many insects also exhibit a form of immune memory (immune priming), where prior exposure to a low dose of infection confers protection against subsequent infection by the same pathogen that acts both within and across generations. Most strikingly, they can rapidly evolve as a highly parallel and mutually exclusive strategy from basal immunity, under different selective conditions and with divergent evolutionary trade-offs. However, the relative importance of priming as an optimal immune strategy also has contradictions, primarily because supporting mechanisms are still unclear. In this review, we adopt a comparative approach to highlight several emerging evolutionary, ecological and mechanistic features of priming vs basal immune responses that warrant immediate attention for future research.

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