Formal assessment of some properties of Context-Aware Systems

Context-Aware systems are becoming useful components in autonomic and monitoring applications and the assessment of their properties is an important step towards reliable implementation, especially in safety-critical applications. In this paper, using an avalanche/landslide alert system as a running example, we propose a technique, based on Boolean Control Networks, to verify that the system dynamics has stable equilibrium states, corresponding to constant inputs, and hence it does not exhibit oscillatory behaviors, and to establish other useful properties in order to implement a precise and timely alarm system

THOR: A Hybrid Recommender System for the Personalized Travel Experience

One of the travelers’ main challenges is that they have to spend a great effort to find and choose the most desired travel offer(s) among a vast list of non-categorized and non-personalized items. Recommendation systems provide an effective way to solve the problem of information overload. In this work, we design and implement “The Hybrid Offer Ranker” (THOR), a hybrid, personalized recommender system for the transportation domain. THOR assigns every traveler a unique contextual preference model built using solely their personal data, which makes the model sensitive to the user’s choices. This model is used to rank travel offers presented to each user according to their personal preferences. We reduce the recommendation problem to one of binary classification that predicts the probability with which the traveler will buy each available travel offer. Travel offers are ranked according to the computed probabilities, hence to the user’s personal preference model. Moreover, to tackle the cold start problem for new users, we apply clustering algorithms to identify groups of travelers with similar profiles and build a preference model for each group. To test the system’s performance, we generate a dataset according to some carefully designed rules. The results of the experiments show that the THOR tool is capable of learning the contextual preferences of each traveler and ranks offers starting from those that have the higher probability of being selected

Aspectos ecofisiológicos da germinação de sementes em biótipos de Sagittaria montevidensis resistentes e suscetível a herbicidas

The objective of this work was to evaluate the ecophysiological aspects of seed germination in California arrowhead (Sagittaria montevidensis) biotypes resistant and susceptible to herbicides. The experimental design was completely randomized. In paddy rice fields, seeds were collected from two biotypes that are resistant (SAGMO 10 and SAGMO 32) and from one that is susceptible (SAGMO 35) to acetolactate synthase and photosystem II inhibiting herbicides. Seed dormancy release was performed with 2.0% potassium nitrate, chemical (1.0% H2SO4 for 30 s) and mechanical (sandpaper) scarification, 10 ppm gibberellic acid, water imbibition for 24 hours, water bath at 60°C, and a control. Germination was evaluated at temperatures from 10 to 40°C and seedling emergence at 0.0, 0.5, 1.0, 2.0, 4.0, and 5.0 cm burial depths. All biotypes showed a germination higher than 70% after mechanical scarification. The highest germination rate occurs at 25.9°C for SAGMO 35, the susceptible biotype, and at 26.2 and 26.5°C, respectively, for SAGMO 10 and SAGMO 32, the resistant biotypes. For all biotypes, the highest seedling emergence occurs in seeds positioned at the 0.5 and 1.0 cm burial depths.O objetivo deste trabalho foi avaliar aspectos ecofisiológicos da germinação de sementes em biótipos de sagitária (Sagittaria montevidensis) resistentes e suscetível a herbicidas. O delineamento experimental foi o inteiramente casualizado. Em campos de arroz, foram colhidas sementes de dois biótipos resistentes (SAGMO 10 e SAGMO 32) e de um suscetível (SAGMO 35) aos herbicidas inibidores da acetolactato sintase e do fotossistema II. A liberação da dormência foi realizada com 2,0% de nitrato de potássio, escarificação química (1,0% de H2SO4 por 30 s) e mecânica (lixa), 10 ppm de ácido giberélico, embebição em água por 24 horas, banho-maria a 60oC e um controle. Avaliaram-se a germinação às temperaturas de 10 a 40°C e a emergência de plântulas aos 0,0, 0,5, 1,0, 2,0, 4,0 e 5,0 cm de profundidade de enterrio. Todos os biótipos apresentaram germinação superior a 70% após escarificação mecânica. A maior taxa de germinação ocorre a 25,9°C para SAGMO 35, o biótipo suscetível, e a 26,2 e 26,5°C, respectivamente, para SAGMO 10 e SAGMO 32, biótipos resistentes. Para todos os biótipos, a maior emergência de plântulas ocorre em sementes posicionadas a 0,5 e 1,0 cm de profundidade de enterrio

Horizontal rotation signals detected by "G-Pisa" ring laser for the Mw=9.0, March 2011, Japan earthquake

We report the observation of the ground rotation induced by the Mw=9.0, 11th of March 2011, Japan earthquake. The rotation measurements have been conducted with a ring laser gyroscope operating in a vertical plane, thus detecting rotations around the horizontal axis. Comparison of ground rotations with vertical accelerations from a co-located force-balance accelerometer shows excellent ring laser coupling at periods longer than 100s. Under the plane wave assumption, we derive a theoretical relationship between horizontal rotation and vertical acceleration for Rayleigh waves. Due to the oblique mounting of the gyroscope with respect to the wave direction-of-arrival, apparent velocities derived from the acceleration / rotation rate ratio are expected to be always larger than, or equal to the true wave propagation velocity. This hypothesis is confirmed through comparison with fundamental-mode, Rayleigh wave phase velocities predicted for a standard Earth model.Comment: Accepted for publication in Journal of Seismolog

The Role and Relevance of Experimentation in Informatics

Informatics is a relatively young eld within sci- ence and engineering. Its research and develop- ment methodologies build on the scientic and de- sign methodologies in the classical areas, often with new elements to it. We take an in-depth look at one of the less well-understood methodologies in infor- matics, namely experimentation. What does it mean to do experiments in in- formatics? Does it make sense to `import' tradi- tional principles of experimentation from classical disciplines into the eld of computing and informa- tion processing? How should experiments be docu- mented? These are some of the questions that are treated. The report argues for the key role of empiri- cal research and experimentation in contemporary Informatics. Many IT systems, large and small, can only be designed sensibly with the help of experiments. We recommend that professionals and students alike are well-educated in the prin- ciples of sound experimentation in Informatics. We also recommend that experimentation protocols are used and standardized as part of the experimental method in Informatic

First demonstration of 6 dB quantum noise reduction in a kilometer scale gravitational wave observatory

Photon shot noise, arising from the quantum-mechanical nature of the light, currently limits the sensitivity of all the gravitational wave observatories at frequencies above one kilohertz. We report a successful application of squeezed vacuum states of light at the GEO\,600 observatory and demonstrate for the first time a reduction of quantum noise up to $6.03 \pm 0.02$ dB in a kilometer-scale interferometer. This is equivalent at high frequencies to increasing the laser power circulating in the interferometer by a factor of four. Achieving this milestone, a key goal for the upgrades of the advanced detectors, required a better understanding of the noise sources and losses, and implementation of robust control schemes to mitigate their contributions. In particular, we address the optical losses from beam propagation, phase noise from the squeezing ellipse, and backscattered light from the squeezed light source. The expertise gained from this work carried out at GEO 600 provides insight towards the implementation of 10 dB of squeezing envisioned for third-generation gravitational wave detectors

Challenges in the Cardiothoracic and Vascular Anesthesia Fellowship Program Since the Coronavirus Disease 2019 (COVID-19) Pandemic: An Electronic Survey on Potential Solutions

OBJECTIVE: We explored the current practice of fellowship training in cardiothoracic and vascular anesthesia and surveyed the acceptability of potential solutions to mitigate the interrupted fellowship training during the severe acute respiratory syndrome coronavirus disease (COVID-19) pandemic. DESIGN: A prospective electronic questionnaire-based survey. SETTING: The survey was initiated by the Education Committee of the European Association of Cardiothoracic Anesthesiology and Intensive Care (EACTAIC) PARTICIPANTS: EACTAIC fellows, EACTAIC and non-EACTAIC subscribers to the EACTAIC newsletter and EACTAIC followers on different social media platforms. INTERVENTIONS: After obtaining the consent of participants, we assessed the peri-operative management of COVID-19 patients, infrastructural aspects of the workplace, local routines for preoperative testing, the perceived availability of personal protective equipment (PPE) and the impact of COVID-19 on fellowship training. In addition participants rated suggested solutions by the investigators to cope with the interruption of fellowship training using a traffic light signal scale. MEASUREMENTS AND MAIN RESULTS: We collected 193 responses from 54 countries. 82.4% of respondents reported cancelling or postponing elective cases during the first wave. Of the respondents, 89.7% had provided care for COVID-19 patients, 75.1% reported staff in their center being reassigned to work in the Intensive Care Unit (ICU), and 45% perceived a shortage of PPE at their centers. Most respondents reported the termination of local educational activities (79.6%) and fellowship assessments (51.5%) because of the pandemic (although 84% of them reported having time to participate in online teaching), and 83% reported a definitive psychological impact. More than 90% of the respondents chose green and/or yellow traffic lights to rate the importance of the suggested solutions to cope with the interrupted fellowship training during the pandemic. CONCLUSIONS: The COVID-19 pandemic led to the cancellation of elective cases, deployment of anesthesiologists to intensive care units, involvement of anesthesiologists in perioperative care for COVID-19 patients, and interruption of educational activities and trainees’ assessments. There is some consensus on suggested solutions for mitigation of the interruption in fellowship training