Concurrent Computing with Shared Replicated Memory

The behavioural theory of concurrent systems states that any concurrent system can be captured by a behaviourally equivalent concurrent Abstract State Machine (cASM). While the theory in general assumes shared locations, it remains valid, if different agents can only interact via messages, i.e. sharing is restricted to mailboxes. There may even be a strict separation between memory managing agents and other agents that can only access the shared memory by sending query and update requests to the memory agents. This article is dedicated to an investigation of replicated data that is maintained by a memory management subsystem, whereas the replication neither appears in the requests nor in the corresponding answers. We show how the behaviour of a concurrent system with such a memory management can be specified using concurrent communicating ASMs. We provide several refinements of a high-level ground model addressing different replication policies and internal messaging between data centres. For all these refinements we analyse their effects on the runs such that decisions concerning the degree of consistency can be consciously made.Comment: 23 page

Adolescents with Type 1 diabetes mellitus experience psychosensorial symptoms during hypoglycaemia

AimTo describe mood and psychosensorial symptoms of hypoglycaemia in adolescents with Type 1 diabetes mellitus in two countries with different cultures, Turkey and the USA.MethodsWe developed a 68-item questionnaire assessing physical, behavioural, mood and psychosensorial symptom frequency and ratings [‘good’, ‘bad’, or ‘both’ (sometimes good, sometimes bad)]. Adolescents with Type 1 diabetes were recruited from paediatric diabetes clinics at the University of North Carolina at Chapel Hill in the USA and Kocaeli University in Turkey. The percentages of participants at each clinic who endorsed individual symptoms, symptom categories and symptom ratings were calculated and compared.ResultsCronbach’s α values were > 0.7 for each real symptom category. No symptom items were excluded from the questionnaire analysis based on item-total correlation results which were all > 0.2. Data were collected from 132 participants (69 from University of North Carolina, 63 from Kocaeli University, 54% male). The mean (sd) age of the participants was 14.9 (1.9) years, HbA1c level was 8.7 (1.8) % and duration of Type 1 diabetes was 5.8 (3.7) years. On average, each physical symptom was experienced by 65.2% of participants, each behavioural symptom by 46.5%, each mood symptom by 42.8%, and each psychosensorial symptom by 48.9%. On average, each physical, behavioral, mood and psychosensorial symptom was rated as ‘good’ or ‘both’ by 23.0, 29.1, 36.9 and 37.2% of participants, respectively. There were no symptom differences between the groups in each country.ConclusionsIn addition to the classic physical symptoms experienced during hypoglycaemia, adolescents with Type 1 diabetes report psychosensorial, mood and behavioral symptoms, and some describe them as positive experiences. Symptom experiences were similar in these two countries with different cultures

Residual effects of static stretching and self-myofascial-release exercises on flexibility and lower body explosive strength in well-trained combat athletes

BACKGROUND: The self-myofascial technique is a new exercise modality that is thought to improve muscular performance and restore soft tissue. However, there are limited empirical data demonstrating the efficacy of this technique on athletic performance. OBJECTIVE: The purpose of this study was to determine the effects of self-myofascial-releasing exercises on the residual characteristics of the sit and reach (S&R) and countermovement jump (CMJ) performance in well-trained combat athletes. METHODS: Sixteen well-trained male combat athletes (age: 23.9 ± 3.6 years, mass: 78.78 ± 10.41 kg, combat experience: 12.87 ± 5.23 years) performed three exercise sessions called "aerobic running (AR)", "aerobic running combined with static stretching (AR + SS)", and "aerobic running combined with self-myofascial release (AR + SMR)" at 48 hour intervals in a randomized crossover design. After each session, the subjects performed the S&R and CMJ tests successively with 30-s of rest between the tests at the 15th second and at the 2nd, 4th, 6th, 8th, 10th, 15th, and 30th minute during the recovery period. RESULTS: ANOVA and the post-hoc LSD (Least Significant Difference) test revealed that the AR + SMR treatment increased the flexibility greater than AR + SS (p = 0.029) at the 45th second. Additionally, the AR + SMR treatment resulted in less of a decrease in CMJ height compared to AR + SS at the 10th minute (p = 0.025). A larger decrease in the CMJ height was found after AR + SS compared to the AR and AR + SMR treatments at the 10th and 15th minute, respectively (p = 0.025 and p = 0.038). These results revealed that SMR had no advantage over AR and SS in terms of enhancing flexibility. A statistically insignificant inhibitory effect of SMR was detected on the CMJ performance. SS appeared to have an inhibitory effect on the CMJ performance for approximately 15 minutes. CONCLUSION: SMR may have a detrimental effect on CMJ performance. Trainers or athletes should consider using the SMR technique before training or competition to prevent possible power decrement. © 2017-IOS Press and the authors. All rights reserved

A Partial-Order Based Active Cache for Recommender Systems

Recommender systems aim to substantially reduce information overload by suggesting lists of similar items that users may find interesting. Caching has been a useful technique for reducing stress on limited resources and improving response time. In this paper, we propose an ‘active caching’ technique for recommender systems based on a partial order approach that not only benefits from popularity and temporal locality, but also exploits spatial locality. This approach allows the processing of answers to neighboring non-cached queries in addition to the reporting of cached query results. Test results for several data sets and recommendation techniques show substantial improvement in the cache hit ratio and computational costs, while achieving reasonable recall rates. 1

Collaborative Access Control in WebdamLog

International audienceThe management of Web users' personal information is increasingly distributed across a broad array of applications and systems, including online social networks and cloud-based services. Users wish to share data using these systems, but avoiding the risks of unintended disclosures or unauthorized access by applications has become a major challenge. We propose a novel access control model that operates within a distributed data management framework based on datalog. Using this model, users can control access to data they own and control applications they run. They can conveniently specify access control policies providing flexible tuple-level control derived using provenance information. We present a formal specification of the model, an implementation built using an open-source distributed datalog engine, and an extensive experimental evaluation showing that the computational cost of access control is modest

Adolescents with Type 1 diabetes mellitus experience psychosensorial symptoms during hypoglycaemia

AIM: To describe mood and psychosensorial symptoms of hypoglycaemia in adolescents with Type 1 diabetes mellitus in two countries with different cultures, Turkey and the USA. METHODS: We developed a 68-item questionnaire assessing physical, behavioural, mood and psychosensorial symptom frequency and ratings [‘good’, ‘bad’, or ‘both’ (sometimes good, sometimes bad)]. Adolescents with Type 1 diabetes were recruited from paediatric diabetes clinics at the University of North Carolina at Chapel Hill in the USA and Kocaeli University in Turkey. The percentages of participants at each clinic who endorsed individual symptoms, symptom categories and symptom ratings were calculated and compared. RESULTS: Cronbach’s α values were > 0.7 for each real symptom category. No symptom items were excluded from the questionnaire analysis based on item-total correlation results which were all > 0.2. Data were collected from 132 participants (69 from University of North Carolina, 63 from Kocaeli University, 54% male). The mean (sd) age of the participants was 14.9 (1.9) years, HbA(1c) level was 8.7 (1.8) % and duration of Type 1 diabetes was 5.8 (3.7) years. On average, each physical symptom was experienced by 65.2% of participants, each behavioural symptom by 46.5%, each mood symptom by 42.8%, and each psychosensorial symptom by 48.9%. On average, each physical, behavioral, mood and psychosensorial symptom was rated as ‘good’ or ‘both’ by 23.0, 29.1, 36.9 and 37.2% of participants, respectively. There were no symptom differences between the groups in each country. CONCLUSIONS: In addition to the classic physical symptoms experienced during hypoglycaemia, adolescents with Type 1 diabetes report psychosensorial, mood and behavioral symptoms, and some describe them as positive experiences. Symptom experiences were similar in these two countries with different cultures

Estimating one's own and one's relatives' multiple intelligence: A study from Argentina

With the advents of high-speed networks, fast commodity hardware, and the web, distributed data sources have become ubiquitous. The third edition of the \"Ozsu-Valduriez textbook Principles of Distributed Database Systems [10] reflects the evolution of distributed data management and distributed database systems. In this new edition, the fundamental principles of distributed data management could be still presented based on the three dimensions of earlier editions: distribution, heterogeneity and autonomy of the data sources. In retrospect, the focus on fundamental principles and generic techniques has been useful not only to understand and teach the material, but also to enable an infinite number of variations. The primary application of these generic techniques has been obviously for distributed and parallel DBMS versions. Today, to support the requirements of important data-intensive applications (e.g. social networks, web data analytics, scientific applications, etc.), new distributed data management techniques and systems (e.g. MapReduce, Hadoop, SciDB, Peanut, Pig latin, etc.) are emerging and receiving much attention from the research community. Although they do well in terms of consistency/flexibility/performance trade-offs for specific applications, they seem to be ad-hoc and might hurt data interoperability. The key questions I discuss are: What are the fundamental principles behind the emerging solutions? Is there any generic architectural model, to explain those principles? Do we need new foundations to look at data distribution