Enabling Practical IPsec authentication for the Internet

On the Move to Meaningful Internet Systems 2006: OTM 2006 Workshops (First International Workshop on Information Security (IS'06), OTM Federated Conferences and workshops). Montpellier, Oct,/Nov. 2006There is a strong consensus about the need for IPsec, although its use is not widespread for end-to-end communications. One of the main reasons for this is the difficulty for authenticating two end-hosts that do not share a secret or do not rely on a common Certification Authority. In this paper we propose a modification to IKE to use reverse DNS and DNSSEC (named DNSSEC-to-IKE) to provide end-to-end authentication to Internet hosts that do not share any secret, without requiring the deployment of a new infrastructure. We perform a comparative analysis in terms of requirements, provided security and performance with state-of-the-art IKE authentication methods and with a recent proposal for IPv6 based on CGA. We conclude that DNSSEC-to-IKE enables the use of IPsec in a broad range of scenarios in which it was not applicable, at the price of offering slightly less security and incurring in higher performance costs.Universidad de Montpellier IIPublicad

Options for improving water use efficiency under worsening scarcity: Evidence from the Middle Olifants Sub-Basin in South Africa

Following the political changes in the early 1990s, the South African government introduced a comprehensive reform process for the water sector with the goal of achieving an enhanced and more equitable water management system. This paper analyses the existing water allocation situations and applies a non-linear optimisation model to investigate the optimal intraand inter-regional allocation regimes in the Middle Olifants sub-basin of South Africa. Economic issues such as efficiency gains related to water transfers are discussed and calculated water price elasticities and estimated water demand functions provide necessary fundamentals for further modelling work. Social and environmental aspects are accounted for by including constant water demands in the model. Results show higher benefits from inter-regional water allocation. Reducing water supply levels to conform to the sustainable water supply policy, it can be shown that although water supply is reduced by approximately 50%, total benefits from water use are only reduced by 5% and 11% for inter- and intra-regional allocation regimes, respectively. These results indicate that alternative water allocation mechanisms can serve as policy instruments to offset the effects of water scarcity

A sugar beet chlorophyll a/b binding protein promoter void of G-box like elements confers strong and leaf specific reporter gene expression in transgenic sugar beet

BACKGROUND: Modification of leaf traits in sugar beet requires a strong leaf specific promoter. With such a promoter, expression in taproots can be avoided which may otherwise take away available energy resources for sugar accumulation. RESULTS: Suppression Subtractive Hybridization (SSH) was utilized to generate an enriched and equalized cDNA library for leaf expressed genes from sugar beet. Fourteen cDNA fragments corresponding to thirteen different genes were isolated. Northern blot analysis indicates the desired tissue specificity of these genes. The promoters for two chlorophyll a/b binding protein genes (Bvcab11 and Bvcab12) were isolated, linked to reporter genes, and transformed into sugar beet using promoter reporter gene fusions. Transient and transgenic analysis indicate that both promoters direct leaf specific gene expression. A bioinformatic analysis revealed that the Bvcab11 promoter is void of G-box like regulatory elements with a palindromic ACGT core sequence. The data indicate that the presence of a G-box element is not a prerequisite for leaf specific and light induced gene expression in sugar beet. CONCLUSIONS: This work shows that SSH can be successfully employed for the identification and subsequent isolation of tissue specific sugar beet promoters. These promoters are shown to drive strong leaf specific gene expression in transgenic sugar beet. The application of these promoters for expressing resistance improving genes against foliar diseases is discussed

Exploring the contribution of indigenous medicine to primary healthcare in West Belesa District in northwestern Ethiopia: A qualitative analysis

Background: This study explores the contribution made by indigenous medicine to primary healthcare services in West Belesa Woreda (District) in northwestern Ethiopia. Objective: The study aims to examine the practices of indigenous medicine in three communities in West Belesa Woreda, the perceptions of its use and efficacy among indigenous medical practitioners and biomedical healthcare practitioners, and their views on its role in primary healthcare. Methods: Qualitative research, including in-depth interviews, focus group discussions and direct observation, using an ethnographic design, was conducted from February to April 2017. In total, 16 key informants were interviewed and six focus group discussion sessions were held. Thematic analysis was undertaken to analyze the data. Results: The local pluralistic healthcare system employs both indigenous medicine and biomedicine, often in combination. However, indigenous healing is generally the first choice due to its greater availability, affordability, and cultural acceptability. Malaria, intestinal worms, diarrhea, stomach ache, gastritis, wounds, snake bites, and epilepsy are commonly treated by herbalists with medicines prepared from plants and plant products. Illnesses that are perceived to be due to buda (evil eye) and spirit possession are mostly treated with tsebel (holy water), prayers and spirit exorcism. The findings also show that most modern healthcare providers have negative perceptions towards indigenous medicine, mainly because it lacks standards for prescribing medications. On the other hand, some beneficiaries of indigenous medicine asserted that indigenous healers provide better primary healthcare for spiritual illnesses and bone fractures. Conclusions: Understanding the cultural context of health, illness, and healing, and the involvement of indigenous healers in primary healthcare, may facilitate the provision of compatible treatments consistent with Amhara cultural and religious traditions and the integration of indigenous medicine and biomedicine. [Ethiop. J. Health Dev. 2020; 34(3):191-204] Key words: Indigenous medicine, primary healthcare, qualitative analysis, Ethiopi

Comparing correction methods to reduce misclassification bias

Multivariate analysis of psychological dat

Deciding on different hinting techniques in assessments for intelligent tutoring systems

Intelligent Tutoring Systems (ITSs) must take advantage of their high computing capabilities and capacity for information retrieval in order to provide the most effective methodologies for improving students' learning. One type of ITS provides assessments to students and some help as a hint, when they do not know how to solve a problem. Our thesis is that the type of hinting techniques used without changing the contents can influence the learning gains and aptitudes of students. We have implemented some hinting techniques as an extension to the XTutor ITS. We found that some hinting techniques can produce a signi cant increase in students' knowledge with respect to others, but the improvement and direction of the comparison depended on some other factors such as the topics to which it was applied. We conclude that proper adaptation of hinting techniques based on different information of the systems will imply better student learning gains. In addition, the results of a student survey, which includes the students' ratings of the different hinting features they interacted with, leads to high variances, which reinforce the idea of the importance of adaptation of hinting techniques in these types of systems.This work was supported in part by the MEC-CICYT Learn3 project TIN2008-05163/TSI (Spanish Ministry of Science and Education, Programa Nacional de Tecnologías de la Información y de las Comunicaciones), and the e-Madrid project S2009/TIC-1650 (Madrid Regional Community).Publicad

Enhancement of Student Learning Through the Use of a Hinting Computer e-Learning System and Comparison with Human Teachers

This paper reports the results of an experiment in a Computer Architecture Laboratory course classroom session, in which students were divided into two groups for interaction both with a hinting e-learning system and with human teachers generating hints. The results show that there were high learning gains for both groups, demonstrating the effectiveness of the human teachers as well as of the computer-based hinting e-learning system even without the use of adaptive and personalization capabilities. In addition, in the worst case, the difference in favor of human teachers (with a low student-to-teacher ratio of 13.5 students per teacher) would not be significant with respect to the e-learning system, so the computer-based system can replace teachers without a significant loss of effectiveness.This work was supported in part by the Learn3 project TIN2008-05163/TSI within the Spanish “Plan Nacional de I+D+I,” and by the Madrid regional community project eMadrid S2009/TIC-1650.Publicad

Constraints on Mars Aphelion Cloud Belt Phase Function and Ice Crystal Geometries

This study constrains the lower bound of the scattering phase function of Martian water ice clouds (WICs) through the implementation of a new observation aboard the Mars Science Laboratory (MSL). The Phase Function Sky Survey (PFSS) was a multiple pointing all-sky observation taken with the navigation cameras (Navcam) aboard MSL. The PFSS was executed 35 times during the Aphelion Cloud Belt (ACB) season of Mars Year 34 over a solar longitude range of L_s=61.4{\deg}-156.5{\deg}. Twenty observations occurred in the morning hours between 06:00 and 09:30 LTST, and 15 runs occurred in the evening hours between 14:30 and 18:00 LTST, with an operationally required 2.5 hour gap on either side of local noon due the sun being located near zenith. The resultant WIC phase function was derived over an observed scattering angle range of 18.3{\deg} to 152.61{\deg}, normalized, and compared with 9 modeled phase functions: seven ice crystal habits and two Martian WIC phase functions currently being implemented in models. Through statistical chi-squared probability tests, the five most probable ice crystal geometries observed in the ACB WICs were aggregates, hexagonal solid columns, hollow columns, plates, and bullet rosettes with p-values greater than or equal to 0.60, 0.57,0.56,0.56, and 0.55, respectively. Droxtals and spheres had p-values of 0.35, and 0.2, making them less probable components of Martian WICs, but still statistically possible ones. Having a better understanding of the ice crystal habit and phase function of Martian water ice clouds directly benefits Martian climate models which currently assume spherical and cylindrical particles.Comment: Accepted Manuscript by Planetary and Space Scienc

Using bluetooth to implement a pervasive indoor positioning system with minimal requirements at the application level

Proyecto CCG10-UC3M/TIC-4992 de la Comunidad Autónoma de Madrid y la Universidad Carlos III de MadridPublicad

Massive Open Online Courses: Combining Methodologies and Architecture for a Success Learning

Massive Open Online Courses: Combining Methodologies and Architecture for a Success Learnin