Desynchronization of simulation and optimization algorithms in HPC Environment

Need for scalability of an algorithm is essential, when one wants to utilize HPC infrastructure in an efficient and reasonable way. In such infrastructures, synchronization affects the efficiency of the parallel algorithms. However, one can consider introducing certain means of desynchronization in order to increase scalability. Allowing for omitting or delaying certain messages, can be easily accepted in the case of metaheuristics. Furthermore, some simulations can also follow this pattern and handle bigger environments. The paper presents a short survey of desynchronization idea, pointing out already obtained results or sketching out the future work focused on scaling the parallel and distributed computing or simulation algorithms leveraging desynchronization

Population Diversity in Ant-inspired Optimization Algorithms

Finding a balance between exploration and exploitation is very important in the case of metaheuristics optimization, especially in the systems leveraging population of individuals expressing (as in Evolutionary Algorithms, etc.) or constructing (as in Ant Colony Optimization) solutions. Premature convergence is a real problem and finding means of its automatic detection and counteracting are of great importance. Measuring diversity in Evolutionary Algorithms working in real-value search space is often computationally complex, but feasible while measuring diversity in combinatorial domain is practically impossible (cf. Closest String Problem). Nevertheless, we propose several practical and feasible diversity measurement techniques dedicated to Ant Colony Optimization algorithms, leveraging the fact that even though analysis of the search space is at least an NP problem, we can focus on the pheromone table, where the direct outcomes of the search are expressed and can be analyzed. Besides proposing the measurement techniques, we apply them to assess the diversity of several variants of ACO, and closely analyze their features for the classic ACO. The discussion of the results is the first step towards applying the proposed measurement techniques in auto-adaptation of the parameters affecting directly the exploitation and exploration features in ACO in the future

The level of knowledge on smoking on the progression of disease in patients with chronic obstructive pulmonary disease : preliminary results

Chronic obstructive pulmonary disease (COPD) is a frequent disease: around 2 million Poles suffer of the COPD. The disease usually begins at the age of 30 and can continue for several decades. Development of the COPD is mainly caused by an active smoking, passive exposure to tobacco smoke and also certain occupational exposition on harmful smokes, dusts, gases, air pollution, as well as the infection of the respiratory system in childhood and such other factors as: a deficient of the a-1 antitripsine and the development disorder of lungs during the embryonic life period. The aim of the paper was to evaluate: - the level of COPD-affected patients’ knowledge on the subject of harmfulness of smoking and the latter's influence on the development of the disease; - patients' attempt to quit the addiction. The study employed a questionnaire consisting of two parts and containing 37 questions. The first part contained socioeconomic questions characterizing the examined group of COPD-diagnosed patients, while the second part included questions relating to the length of duration of the disease, occurrence of individual risk factors, the respondents' smoking record, their sources and level of knowledge concerning COPD. The survey comprised a group of 30 patients (4 women and 26 men) hospitalized as a result of an aggravation of the COPD. Only one of the respondents had never smoked. The remaining respondents, i.e. 97%, were smokers at the moment of COPD diagnosis. At present, approximately 3/4 of the surveyed COPD-diagnosed patients have ceased smoking. The primary factor which induced them to abandon the habit was the diagnosis of the Chronic Obstructive Pulmonary Disease. However, despite disease exacerbation 23% of the respondents still smoke. The analysis of the survey indicates that nearly 2/3 of the respondents possess knowledge with regard to the significance of smoking in the development and the course of COPD. Moreover, the majority of the surveyed population, i.e. 94%, is aware of the addictive impact of nicotine. All the patients realize the harm caused by smoking in respiratory, cardiovascular and alimentary system. The conducted study demonstrated that the majority of the respondents possessed correct information concerning the effects of smoking on the development and the course of COPD. For the majority of the smokers, the diagnosis of COPD entailed discontinuance of the smoking addiction. However, almost every fourth of the respondents smoke in spite of the diagnosis of the COPD

Poziom wiedzy pacjentów z przewlekłą obturacyjną chorobą płuc na temat wpływu nikotynizmu na rozwój choroby. Wyniki wstępne

Background. Chronic obstructive pulmonary disease (COPD) is a frequent disease: around 2 million Poles suffer of the COPD. The disease usually begins at the age of 30 and can continue for several decades. Development of the COPD is mainly caused by an active smoking, passive exposure to tobacco smoke and also certain occupational exposition on harmful smokes, dusts, gases, air pollution, as well as the infection of the respiratory system in childhood and such other factors as: a deficient of the a-1 antitripsine and the development disorder of lungs during the embryonic life period. Aim. The aim of the paper was to evaluate: - the level of COPD-affected patients’ knowledge on the subject of harmfulness of smoking and the latter’s influence on the development of the disease; - patients’ attempt to quit the addiction. Material and methods. The study employed a questionnaire consisting of two parts and containing 37 questions. The first part contained socioeconomic questions characterizing the examined group of COPD-diagnosed patients, while the second part included questions relating to the length of duration of the disease, occurrence of individual risk factors, the respondents’ smoking record, their sources and level of knowledge concerning COPD. The survey comprised a group of 30 patients (4 women and 26 men) hospitalized as a result of an aggravation of the COPD. Results and conclusions. Only one of the respondents had never smoked. The remaining respondents, i.e. 97%, were smokers at the moment of COPD diagnosis. At present, approximately 3/4 of the surveyed COPD-diagnosed patients have ceased smoking. The primary factor which induced them to abandon the habit was the diagnosis of the Chronic Obstructive Pulmonary Disease. However, despite disease exacerbation 23% of the respondents still smoke. The analysis of the survey indicates that nearly 2/3 of the respondents possess knowledge with regard to the significance of smoking in the development and the course of COPD. Moreover, the majority of the surveyed population, i.e. 94%, is aware of the addictive impact of nicotine. All the patients realize the harm caused by smoking in respiratory, cardiovascular and alimentary system. The conducted study demonstrated that the majority of the respondents possessed correct information concerning the effects of smoking on the development and the course of COPD. For the majority of the smokers, the diagnosis of COPD entailed discontinuance of the smoking addiction. However, almost every fourth of the respondents smoke in spite of the diagnosis of the COPD.Wstęp. Przewlekła obturacyjna choroba płuc (COPD, chronic obstructive pulmonary disease) jest chorobą częstą. Szacuje się, że w Polsce choruje na nią około 2 mln ludzi. Choroba ta może trwać kilkadziesiąt lat. Zaczyna się zwykle około 30. roku życia. Rozwojowi COPD sprzyjają głównie palenie tytoniu, bierne narażenie na dym tytoniowy, a także narażenie zawodowe na szkodliwe dymy, pyły i gazy, zanieczyszczenie powietrza, infekcje układu oddechowego w dzieciństwie oraz czynniki osobnicze, takie jak: niedobór antytrypsyny a-1 i zaburzenia rozwoju płuc w okresie życia płodowego. Cel. Celem pracy była ocena: - zakresu wiedzy chorych na COPD na temat szkodliwości palenia tytoniu i jego związku z rozwojem choroby; - podejmowania przez chorych walki z nałogiem. Materiał i metody. W badaniu wykorzystano kwestionariusz ankiety, który składał się z dwóch części i zawierał 37 pytań. Pierwsza część obejmowała pytania socjoekonomiczne, charakteryzujące badaną grupę pacjentów z COPD, natomiast druga - pytania dotyczące czasu trwania choroby, występowania indywidualnych czynników ryzyka, historii palenia tytoniu przez ankietowanych, źródeł i poziomu wiedzy badanych na temat COPD. Badaniem objęto grupę 30 pacjentów (4 kobiety, 26 mężczyzn) hospitalizowanych z powodu zaostrzenia COPD. Wyniki i wnioski. Tylko jeden ankietowany nigdy nie palił. Pozostali ankietowani (97%) byli osobami palącymi w okresie rozpoznania COPD. Obecnie blisko 3/4 badanych pacjentów z COPD przestało palić papierosy. Głównym czynnikiem, który skłonił do zerwania z nałogiem, było zdiagnozowanie przewlekłej obturacyjnej choroby płuc. Mimo zaostrzeń choroby 23% ankietowanych nadal pali tytoń. Z analizy badań wynika, że prawie 2/3 respondentów wie, jakie znaczenie w rozwoju i przebiegu COPD ma palenie tytoniu. Przeważająca większość, bo 94% badanej populacji, ma świadomość uzależniającego działania nikotyny. Wszyscy pacjenci orientują się, jakie szkody powoduje palenie tytoniu w układzie oddechowym, krążenia i pokarmowym. W przeprowadzonych badaniach wykazano, że większość respondentów dysponuje prawidłowymi informacjami o wpływie palenia tytoniu na rozwój i przebieg COPD. U większości palaczy rozpoznanie COPD łączyło się z zerwaniem z nałogiem palenia tytoniu. Jednak prawie co czwarty ankietowany palił pomimo rozpoznania COPD

Flexible asynchronous simulation of iterated prisoner's dilemma based on actor model

The wide range of applications of the Iterated prisoner's dilemma (IPD) game made it a popular subject of study for the research community. As a consequence, numerous experiments have been conducted by researchers along the last decades. However, topics related with scaling simulation leveraging existing HPC infrastructure in the field of IPD did not always play a relevant role in such experimental work. The main contribution of this paper is a new simulation framework, based on asynchronous communication and its implementation oriented to distributed environments. Such framework is based on the modern Akka actor platform, that supports concurrent, distributed and resilient message-driven simulations; which are exemplified over the IPD game as a case study. We also present several interesting results regarding the introduction of asynchrony into the IPD simulation in order to obtain an efficient framework, so the whole simulation becomes scalable when using HPC facilities. The influence of asynchrony on the algorithm itself is also discussed, and the results show that it does not hamper the simulation.SCOPUS: ar.jinfo:eu-repo/semantics/publishe