Improving photon-hadron discrimination based on cosmic ray surface detector data

The search for photons at EeV energies and beyond has considerable astrophysical interest and will remain one of the key challenges for ultra-high energy cosmic ray (UHECR) observatories in the near future. Several upper limits to the photon flux have been established since no photon has been unambiguously observed up to now. An improvement in the reconstruction efficiency of the photon showers and/or better discrimination tools are needed to improve these limits apart from an increase in statistics. Following this direction, we analyze in this work the ability of the surface parameter Sb, originally proposed for hadron discrimination, for photon search. Semi-analytical and numerical studies are performed in order to optimize Sb for the discrimination of photons from a proton background in the energy range from 10^18.5 to 10^19.6 eV. Although not shown explicitly, the same analysis has been performed for Fe nuclei and the corresponding results are discussed when appropriate. The effects of different array geometries and the underestimation of the muon component in the shower simulations are analyzed, as well as the Sb dependence on primary energy and zenith angle.Comment: 9 pages, 19 Figures. Accepted in Astroparticle Physics on May 31th, 201

BARTER: Behavior Profile Exchange for Behavior-Based Admission and Access Control in MANETs

Mobile Ad-hoc Networks (MANETs) are very dynamic networks with devices continuously entering and leaving the group. The highly dynamic nature of MANETs renders the manual creation and update of policies associated with the initial incorporation of devices to the MANET (admission control) as well as with anomaly detection during communications among members (access control) a very difficult task. In this paper, we present BARTER, a mechanism that automatically creates and updates admission and access control policies for MANETs based on behavior profiles. BARTER is an adaptation for fully distributed environments of our previously introduced BB-NAC mechanism for NAC technologies. Rather than relying on a centralized NAC enforcer, MANET members initially exchange their behavior profiles and compute individual local definitions of normal network behavior. During admission or access control, each member issues an individual decision based on its definition of normalcy. Individual decisions are then aggregated via a threshold cryptographic infrastructure that requires an agreement among a fixed amount of MANET members to change the status of the network. We present experimental results using content and volumetric behavior profiles computed from the ENRON dataset. In particular, we show that the mechanism achieves true rejection rates of 95% with false rejection rates of 9%

BARTER: Profile Model Exchange for Behavior-Based Access Control and Communication Security in MANETs

There is a considerable body of literature and technology that provides access control and security of communication for Mobile Ad-hoc Networks (MANETs) based on cryptographic authentication technologies and protocols. We introduce a new method of granting access and securing communication in a MANET environment to augment, not replace, existing techniques. Previous approaches grant access to the MANET, or to its services, merely by means of an authenticated identity or a qualified role. We present BARTER, a framework that, in addition, requires nodes to exchange a model of their behavior to grant access to the MANET and to assess the legitimacy of their subsequent communication. This framework forces the nodes not only to say who or what they are, but also how they behave. BARTER will continuously run membership acceptance and update protocols to give access to and accept traffic only from nodes whose behavior model is considered "normal" according to the behavior model of the nodes in the MANET. We implement and experimentally evaluate the merger between BARTER and other cryptographic technologies and show that BARTER can implement a fully distributed automatic access control and update with small cryptographic costs. Although the methods proposed involve the use of content-based anomaly detection models, the generic infrastructure implementing the methodology may utilize any behavior model. Even though the experiments are implemented for MANETs, the idea of model exchange for access control can be applied to any type of network

Servitization strategies from customers’ perspective: the moderating role of co-creation

© 2018, Emerald Publishing Limited. Purpose: This paper aims to investigate the moderating role of co-creation in the implementation of servitization strategies in the pharmaceutical industry in a business-to-business (B-to-B) context. More specifically, this investigation explores the impact of different levels of services (base, intermediate and advanced) on servitization and on performance by using co-creation as a moderating factor. Design/methodology/approach: A research framework was developed and empirically tested in the pharmaceutical sector. Data collection was conducted through the online distribution of questionnaires. The final sample included 219 pharmacy stores, and the data were analysed using structural equation modelling. Findings: Main findings suggest that when the level of co-creation of the design of services is high, there are significant effects of servitization on firm performance. The moderating effect of co-creation is illustrated in regard to intermediate and advanced services, but results referring to the impact of intermediate services on servitization appear non-significant with a low degree of co-creation. No significant effects could be found for the impact of base services on performance and servitization for both high and low degrees of co-creation. Findings show an impact of advanced services on performance through the mediating effect of servitization when the degree of co-creation is high. Originality/value: Most research concerning servitization has been done from the perspective of manufacturers and service providers. This study adds value to the literature because it was designed from a customer’s perspective. Moreover, it contributes towards the conceptualization of the servitization research strategy and business models in a B2B context. This is accomplished through the investigation of the moderating effect of co-creation on the impact of the different levels of services on servitization and on performance

Lessons from market-based approaches to improved hygiene for the rural poor in developing countries

The countries that adopted the Millennium Development Goals (MDGs) have pledged to halve the proportion of the people without access to water supply and sanitation by the year 2015. Existing strategies have been slowed in closing the gap. Few countries have long-term, financially viable programs and many programs deliver a standard heavily subsidized model, which does not reach many of the poor in the short-term. This paper discusses alternative strategies that focus on effective, low-cost water treatment and sanitation technologies that aim to reach more people for far less cost than conventional approaches. This approach is particularly relevant to the vulnerable groups of the population and poor regions of developing countries. Experience and illustrations come from Cambodia and Vietnam where nearly 80% of the poor live in rural areas and the market for small-scale water supply and sanitation is relatively underdeveloped

Towards 5G: scenario-based assessment of the future supply and demand for mobile telecommunications infrastructure

Moving from 4G LTE to 5G is an archetypal example of technological change. Mobile Network Operators (MNOs) who fail to adapt will likely lose market share. Hitherto, qualitative frameworks have been put forward to aid with business model adaptation for MNOs facing on the one hand increasing traffic growth, while on the other declining revenues. In this analysis, we provide a complementary scenario-based assessment of 5G infrastructure strategies in relation to mobile traffic growth. Developing and applying an open-source modelling framework, we quantify the uncertainty associated with future demand and supply for a hypothetical MNO, using Britain as a case study example. We find that over 90% of baseline data growth between 2016 and 2030 is driven by technological change, rather than demographics. To meet this demand, spectrum strategies require the least amount of capital expenditure and can meet baseline growth until approximately 2025, after which new spectrum bands will be required. Alternatively, small cell deployments provide significant capacity but at considerable cost, and hence are likely only in the densest locations, unless MNOs can boost revenues by capturing value from the Internet of Things (IoT), Smart Cities or other technological developments dependent on digital connectivity.Edward Oughton, Zoraida Frias, Tom Russell and David Cleevely would like to express their gratitude to the UK Engineering and Physical Science Research Council for funding via grant EP/N017064/1: Multi-scale InfraSTRucture systems AnaLytics (Mistral). Zoraida Frias would like to thank the Universidad Politécnica de Madrid for their support through the mobility program scholarship