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2. Network motifs for translator stylometry identification

Author

El-Fiqi, H, Petraki, E, Abbass, HA, El-Fiqi, H, Petraki, E, and Abbass, HA

Abstract

Despite the extensive literature investigating stylometry analysis in authorship attribution research, translator stylometry is an understudied research area. The identification of translator stylometry contributes to many fields including education, intellectual property rights and forensic linguistics. In a two stage process, this paper first evaluates the use of existing lexical measures for the translator stylometry problem. Similar to previous research we found that using vocabulary richness in its traditional form as it has been used in the literature could not identify translator stylometry. This encouraged us to design an approach with the aim of identifying the distinctive patterns of a translator by employing network-motifs. Networks motifs are small sub-graphs which aim at capturing the local structure of a complex network. The proposed approach achieved an average accuracy of 83% in three-way classification. These results demonstrate that classic tools based on lexical features can be used for identifying translator stylometry if they get augmented with appropriate non-parametric scaling. Moreover, the use of complex network analysis and network motifs mining provided made it possible to design features that can solve translator stylometry analysis problems.

Published
2019

3. Human–Guided Evolutionary Story Narration

Author

Wang, K, Bui, V, Petraki, E, Abbass, H, Wang, K, Bui, V, Petraki, E, and Abbass, H

Abstract

Stories are useful tools with which we can exchange experience learnt in social contexts, ways to communicate futures in strategic planning, and unique building blocks that connect meanings in a movie or a virtual environment. Evolutionary computation (EC) techniques have the potential to overcome existing limitations in automated storytelling, whereby evolution can provide a process of innovation. However, one source of complexity lies in the transformation of a story in a natural language into a representation that EC can evolve easily. Another complexity arises from the fact that the ultimate judge for the quality of a story is a human–being, and humans are diverse in their taste. This paper attempts to tackle the above complexities through an automatic story narration application. We present a methodology which can transform a story written in English into an event-level and hierarchical level grammar using a network representation. This approach makes it possible to devise an encoding scheme that translates a story narration with flashback into a chromosome and vice versa. We then discuss different metrics for the evolutionary narration problem and use 42 human participants to evaluate the generated narrations. To incorporate diversified human opinions, we propose to build individual human surrogate models from the human evaluation experiment and further fuse them into an ensemble. The ensembles of human surrogate models serve as the objective functions of multi-objective EC to guide the generation of desirable stories from human perspectives. We demonstrate that this approach is successful in evolving better narrations as assessed by 31 human participants.

Published
2018

4. Fractal evolution of MHz electromagnetic signals prior to earthquakes: results collected in Greece during 2009

Author

Petraki, E. Nikolopoulos, D. Chaldeos, Y. Koulouras, G. Nomicos, C. Yannakopoulos, P.H. Kottou, S. Stonham, J.

Subjects
Physics::Geophysics
Abstract

This paper addressed a fractal evolution of 11 one-month lasting MHz electromagnetic disturbances, recorded in Greece prior to nine significant earthquakes of 2009. Time-space wavelet-based power spectral techniques were employed in the analysis. All investigated signals evolved naturally to epochs of fractal organization in space and time. Continuous organization was detected in seven signals. Significant number of successive (Formula presented.) power-law (Formula presented.) -values were observed lying between 1.5 and 3.0 or above. The majority of fractal segments exhibited anti-persistent (Formula presented.) or persistent (Formula presented.) behaviour. Switching between persistency and anti-persistency was also found. Locality and sensitivity were traced. Findings were considered indicative of self-organized critical states of the last stages of preparation of the investigated earthquakes. Results implied fractional Brownian modelling. Explanations were proposed in view of the asperity model. Persistent–anti-persistent MHz anomalies were due to self-organized micro-cracking of the heterogeneous medium of the earth's crust which may have led the system's evolution towards global failure. The precursory value of the signals was discussed. © 2014 Taylor & Francis.

Published
2016

5. Preliminary background indoor EMF measurements in Greece

Author

Kottou, S. Nikolopoulos, D. Yannakopoulos, P.H. Vogiannis, E. Petraki, E. Panagiotaras, D. Koulougliotis, D.

Abstract

The main purpose of this work was to investigate the fluctuation of Greek indoor electromagnetic field (EMF) intensity values and identify peaks that might occur. The scientific interest is mainly focused on the bands of extremely low-frequency (ELF) magnetic fields and radiofrequency (RF) electric fields which have been suggested to be possibly carcinogenic to humans by the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR).Electromagnetic radiation (EMR) measurements were performed in a variety of indoor dwellings, in Attica and in the islands of Zakynthos and Lesvos.A total number of 4540 measurements were taken in a wide frequency range (50 Hz-2100 MHz) of which 3301 in Attica, 963 in Lesvos and 276 in Zakynthos.Statistical analysis of the data revealed specific statistically significant differences between the mean values of the electric (ELF and RF) but not the magnetic (ELF) field strengths measured at different distances from the EMF source, as well as between some of the mean values of the RF electric field at different bands. Some statistically significant differences between mean electric field values at different geographic locations were also identified.As far as the RF electric field is concerned, the maximum values, in most cases, were below 0.5 V/m, however increased values above 1 V/m and up to 5.6 V/m were occasionally observed. The ELF magnetic field values were lower than 1 μT. It may be concluded that overall, the observed indoor EMF intensity values remained well below domestic and European established limits. © 2015 Associazione Italiana di Fisica Medica.

Published
2015

6. Database cracking

Author

Pirk, H., Petraki, E., Idreos, S., Manegold, S., Kersten, M., Kemper, A., Pandis, P., Intelligent Sensory Information Systems (IVI, FNWI), and Database Architectures

Subjects
Core (game theory), Cracking, Single pass, Database, Computer science, Server, sort, Ranging, Memory bandwidth, Parallel computing, computer.software_genre, computer, Implementation
Abstract

Database Cracking is an appealing approach to adaptive indexing: on every range-selection query, the data is partitioned using the supplied predicates as pivots. The core of database cracking is, thus, pivoted partitioning. While pivoted partitioning, like scanning, requires a single pass through the data it tends to have much higher costs due to lower CPU efficiency. In this paper, we conduct an in-depth study of the reasons for the low CPU efficiency of pivoted partitioning. Based on the findings, we develop an optimized version with significantly higher (single-threaded) CPU efficiency. We also develop a number of multi-threaded implementations that are effectively bound by memory bandwidth. Combining all of these optimizations we achieve an implementation that has costs close to or better than an ordinary scan on a variety of systems ranging from low-end (cheaper than $300) desktop machines to high-end (above $60,000) servers.

Published
2014
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7. The N-Player Trust Game and its Replicator Dynamics

Author

Abbass, H, Greenwood, G, Petraki, E, Abbass, H, Greenwood, G, and Petraki, E

Abstract

Trust is a fundamental concept that underpins the coherence and resilience of social systems and shapes human behavior. Despite the importance of trust as a social and psychological concept, the concept has not gained much attention from evolutionary game theorists. In this letter, an N-player trust-based social dilemma game is introduced. While the theory shows that a society with no untrustworthy individuals would yield maximum wealth to both the society as a whole and the individuals in the long run, evolutionary dynamics show this ideal situation is reached only in a special case when the initial population contains no untrustworthy individuals. When the initial population consists of even the slightest number of untrustworthy individuals, the society converges to zero trusters, with many untrustworthy individuals. The promotion of trust is an uneasy task, despite the fact that a combination of trusters and trustworthy trustees is the most rational and optimal social state. This letter presents the game and results of replicator dynamics in a hope that researchers in evolutionary games see opportunities in filling this critical gap in the literature.

Published
2016

8. Shaping Influence and Influencing Shaping: A Computational Red Teaming Trust-based Swarm Intelligence Model

Author

Tan, Y, Shi, Y, Niu, B, Tang, J, Petraki, E, Abbass, HA, Tan, Y, Shi, Y, Niu, B, Tang, J, Petraki, E, and Abbass, HA

Abstract

Sociotechnical systems are complex systems, where nonlinear interaction among different players can obscure causal relationships. The absence of mechanisms to help us understand how to create a change in the system makes it hard to manage these systems.Influencing and shaping are social operators acting on sociotechnical systems to design a change. However, the two operators are usually discussed in an ad-hoc manner, without proper guiding models and metrics which assist in adopting these models successfully. Moreover, both social operators rely on accurate understanding of the concept of trust. Without such understanding, neither of these operators can create the required level to create a change in a desirable direction.In this paper, we define these concepts in a concise manner suitable for modelling the concepts and understanding their dynamics. We then introduce a model for influencing and shaping and use Computational Red Teaming principles to design and demonstrate how this model operates. We validate the results computationally through a simulation environment to show social influencing and shaping in an artificial society.

Published
2016

9. MonetDB Jul2015-SP2 bugfix release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, Sidirourgos, E. (Eleftherios), Koopmanschap, R.A. (Richard), Raasveldt, M. (Mark), Koutsourakis, P. (Panagiotis), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, Sidirourgos, E. (Eleftherios), Koopmanschap, R.A. (Richard), Raasveldt, M. (Mark), and Koutsourakis, P. (Panagiotis)

Published
2016

10. MonetDB Jun2016 feature release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, Sidirourgos, E. (Eleftherios), Koopmanschap, R.A. (Richard), Raasveldt, M. (Mark), Koutsourakis, P. (Panagiotis), Döhmen, T.R. (Till), Kruit, B.B. (Benno), Wits, A. (Abe), Ferreira, P.E. (Pedro) Silva, Stalinov, S.G. (Svetlin), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, Sidirourgos, E. (Eleftherios), Koopmanschap, R.A. (Richard), Raasveldt, M. (Mark), Koutsourakis, P. (Panagiotis), Döhmen, T.R. (Till), Kruit, B.B. (Benno), Wits, A. (Abe), Ferreira, P.E. (Pedro) Silva, and Stalinov, S.G. (Svetlin)

Published
2016

11. Traces of self-organisation and long-range memory in variations of environmental radon in soil: Comparative results from monitoring in Lesvos Island and Ileia (Greece)

Author

Nikolopoulos, D. Petraki, E. Vogiannis, E. Chaldeos, Y. Yannakopoulos, P. Kottou, S. Nomicos, C. Stonham, J.

Abstract

This paper addresses issues of self-affinity, long-memory and self-organisation in variations of radon in soil recorded in Lesvos Island, Greece. Several techniques were employed, namely (a) power-law wavelet spectral fractal analysis, (b) estimation of Hurst exponents through (b1) rescaled-range, (b2) roughness-length, (b3) variogram and (a), (c) detrended fluctuation analysis, (d) investigation of fractal dimensions and (e) analysis of five block entropies: (e1) Shannon entropy, (e2) Shannon entropy per letter, (e3) conditional entropy, (e4) Tsallis entropy, and (e5) normalised Tsallis entropy. Long-lasting antipersistency was identified during a period of anomalous radon variations following fractional Brownian modelling. Remaining variations did not exhibit analogous behaviour and followed fractional Gaussian modelling. Antipersistent power-law-beta-exponent-values between 1.5 and 2.0 were detected during anomalies. Persistent values were also found. Hurst exponents were mainly within 0 < H < 0.5. Some persistent exponents (0.5 < H < 1) were also observed. Fractal dimensions were within 1.5 < D < 2. Radon anomalies presented lower fractal dimensions. Shannon entropy ranged between 0.77 ≤ H(n) ≤ 2.38, Shannon entropy per letter, between 0.19 ≤ h (n) ≤ 0.59, conditional entropy, between 0.01 ≤ h (n) ≤ 0.58, Tsallis entropy, between 0.55 ≤ S q ≤ 1.01 and normalised Tsallis entropy between, 0.98 ≤ {S} S ≤ 5.42 (block-size n = 4). Entropies were lower during anomalies, indicating strong self-organisation. Persistency-antipersistency switching was observed, consistent with long-memory dynamics. Potential geological sources were discussed. The asperity-model was proposed. Findings were compared to results obtained under analogous methodologies in Ileia, Greece. © 2013 Akadémiai Kiadó, Budapest, Hungary.

Published
2014

12. Self-organised critical features in soil radon and MHz electromagnetic disturbances: Results from environmental monitoring in Greece

Author

Petraki, E. Nikolopoulos, D. Fotopoulos, A. Panagiotaras, D. Koulouras, G. Zisos, A. Nomicos, C. Louizi, A. Stonham, J.

Abstract

This paper addresses the issues of self-organised critical behaviour of soil-radon and MHz-electromagnetic disorders during intense seismic activity in SW Greece. A significant radon signal is re-analysed for environmental influences with Fast Fourier Transform and multivariate statistics. Self-organisation of signals is investigated via fractal evolving techniques and detrended fluctuation analysis. New lengthy radon data are presented and analysed accordingly. The data did not show self-similarities. Similar analysis applied to new important concurrent MHz-electromagnetic signals revealed analogous behaviour to radon. The signals precursory value is discussed. © 2012 Elsevier Ltd.

Published
2013

13. Dosimetry modelling of transient radon and progeny concentration peaks: Results from in situ measurements in Ikaria spas, Greece

Author

Nikolopoulos, D. Vogiannis, E. Petraki, E. Kottou, S. Yannakopoulos, P. Leontaridou, M. Louizi, A.

Abstract

Radon and progeny (218Po, 214Pb, 214Bi and 214Po) are radioactive indoor pollutants recognised for the human radiation burden that they induce. Bathing in thermal spas causes transient concentration peaks of radon and progeny and additional short-term impact in patients and personnel. This paper reports a semi-empirical non-linear first order model for describing radon and progeny variations in treatment rooms of the Ikaria spas. Non-measured physical parameters were estimated from in situ measurements in Ikaria through non-linear numerical solving. Exposure and dose variations were additionally modelled. Attachment rate constants were found to be between 0.44 and 55 h-1. Deposition rate constants were between 0.28 and 7.3 h-1 for attached nuclei and 0.42 and 64 h-1 for unattached nuclei. Unattached progeny peaks were right-shifted compared to those of radon. Modelled effective doses ranged between 0.001 mSv per year and 0.589 mSv per year for patients and between 0.001 mSv per year and 18.9 mSv per year for workers. Apollon spas presented quite high doses. These were the highest reported in Greece and are significant worldwide. © The Royal Society of Chemistry.

Published
2013

14. Environmental monitoring of radon in soil during a very seismically active period occurred in South West Greece

Author

Nikolopoulos, D. Petraki, E. Marousaki, A. Potirakis, S.M. Koulouras, G. Nomicos, C. Panagiotaras, D. Stonham, J. Louizi, A.

Abstract

This paper focuses on the environmental monitoring of radon in soil as a potential trace gas in the search of earthquake precursors. The paper reports the following: (a) Pre-monitoring experiments. (b) Set-up of methods and devices. (c) Active and passive monitoring results concentrating on two extremely-strong radon anomalies (∼ 500 kBq m -3). (e) Discussion regarding the employed ±2σ technique for identifying radon disturbances. (f) Application of wavelet-power-spectrum fractal analysis for detecting power-law behaviour. The strong anomalies exhibited anti-persistent power-law-beta-values (b = (1.8 ± 0.2), b = (1.8 ± 0.3)) significantly higher than those of the baseline. Persistent b-values were also detected. The findings comply with a self-organised-critical pre-earthquake state. (h) Discussion on models that interpret the radon anomalies focusing on the recently-proposed asperity-model. (i) Application of a recent technique which showed that the two strong disturbances were proportional to the strain change. It was concluded that the strong radon disturbances may be linked to the strong earthquake of 8/6/2008, M = 6.5, occurred 29 km away from the installed instrumentation. © 2012 The Royal Society of Chemistry.

Published
2012

16. On trust and influence: A computational red teaming game theoretic perspective

Author

Petraki, E, Abbass, HA, Petraki, E, and Abbass, HA

Abstract

The concept of trust has attracted the attention of many researchers over the years who studied the impact of trust in many domains. Trust is a ubiquitous concept. It is pervasive in every aspect of our life, from interpersonal relationships to national defence and security applications. However, despite the vast literature on trust, we are not close enough to mastering the dynamics of trust. One reason is that if we define procedural steps for trust, we simultaneously define steps for deception; thus, we simply define a vacuous cycle. Another reason is that, the dynamics of trust change as the world changes. But how can we then study trust? This paper connects the interdisciplinary literature to synthesize a Computational Red Teaming (CRT) based model of trust that defines opportunities whereby computational intelligence techniques, more specifically, evolutionary game theory researchers, can contribute to this vastly growing research area. We offer a position on the topic by reviewing games for trust and introduce a new theoretic game to study influence and transfer of trust.

Published
2015

17. Holistic Indexing in Main-memory Column-stores

Author

Petraki, E. (Eleni), Idreos, S. (Stratos), Manegold, S. (Stefan), Petraki, E. (Eleni), Idreos, S. (Stratos), and Manegold, S. (Stefan)

Abstract

Great database systems performance relies heavily on index tuning, i.e., creating and utilizing the best indices depending on the workload. However, the complexity of the index tuning process has dramatically increased in recent years due to ad-hoc workloads and shortage of time and system resources to invest in tuning. This paper introduces holistic indexing, a new approach to automated index tuning in dynamic environments. Holistic indexing requires zero set-up and tuning effort, relying on adaptive index creation as a side-effect of query processing. Indices are created incrementally and partially; they are continuously refined as we process more and more queries. Holistic indexing takes the state-of-the-art adaptive indexing ideas a big step further by introducing the notion of a system which never stops refining the index space, taking educated decisions about which index we should incrementally refine next based on continuous knowledge acquisition about the running workload and resource utilization. When the system detects idle CPU cycles, it utilizes those extra cycles by refining the adaptive indices which are most likely to bring a benefit for future queries. Such idle CPU cycles occur when the system cannot exploit all available cores up to 100%, i.e., either because the workload is not enough to saturate the CPUs or because the current tasks performed for query processing are not easy to parallelize to the point where all available CPU power is exploited. In this paper, we present the design of holistic indexing for column-oriented database architectures and we discuss a detailed analysis against parallel versions of state-of-the-art indexing and adaptive indexing approaches. Holistic indexing is implemented in an open-source column-store DBMS. Our detailed experiments on both synthetic and standard benchmarks (TPC-H) and workloads (SkyServer) demonstrate that holistic indexing brings significant performance gains by being able to continuously refine the

Published
2015
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18. MonetDB Oct2014-SP3 bugfix release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, Sidirourgos, E. (Eleftherios), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, and Sidirourgos, E. (Eleftherios)

Published
2015

19. MonetDB Jul2015 feature release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, Sidirourgos, E. (Eleftherios), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, and Sidirourgos, E. (Eleftherios)

Published
2015

20. MonetDB Jul2015-SP1 bugfix release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, Sidirourgos, E. (Eleftherios), Koopmanschap, R.A. (Richard), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, Sidirourgos, E. (Eleftherios), and Koopmanschap, R.A. (Richard)

Published
2015

21. Investigation of the exposure to radon and progeny in the thermal spas of Loutraki (Attica-Greece): Results from measurements and modelling

Author

Nikolopoulos, D. Vogiannis, E. Petraki, E. Zisos, A. Louizi, A.

Subjects
respiratory tract diseases
Abstract

Radon and progeny (218Po, 214Pb, 214Bi and 214Po) in thermal spas are well known radioactive pollutants identified for additional radiation burden of patients due to the activity concentration peaks which appear during bath treatment or due to drinking of waters of high radon content. This burden affects additionally the working personnel of the spas. The present paper has focused on the thermal spas of Loutraki (Attica-Greece). The aim was the investigation of the health impact for patients and working personnel due to radon and progeny. Attention has been paid to radon and progeny transient concentration peaks (for bath treatment) and to radon of thermal waters (both for bath treatment and drinking therapy). Designed experiments have been carried out, which included radon and progeny activity concentration measurements in thermal waters and ambient air. Additionally, published models for description of radon and progeny transient concentration peaks were employed. The models were based on physicochemical processes involved and employed non linear first order derivative mass balance differential equations which were solved numerically with the aid of specially developed computer codes. The collected measurements were analysed incorporating these models. Results were checked via non linear statistical tests. Predictions and measurements were found in close agreement. Non linear parameters were estimated. The models were employed for dosimetric estimations of patients and working personnel. The effective doses of patients receiving bath treatment were found low but not negligible. The corresponding doses to patients receiving potable treatment were found high but below the proposed international limits. It was found that the working personnel are exposed to considerable effective doses, however well below the acceptable limits for workers. It was concluded that treatment and working in the Loutraki spas leads to intense variations of radon and progeny and consequently additional health impact both to patients and working personnel. © 2009 Elsevier B.V. All rights reserved.

Published
2010

22. Database Cracking: Fancy Scan, not Poor Man’s Sort!

Author

Pirk, H. (Holger), Petraki, E. (Eleni), Idreos, S. (Stratos), Manegold, S. (Stefan), Kersten, M.L. (Martin), Pirk, H. (Holger), Petraki, E. (Eleni), Idreos, S. (Stratos), Manegold, S. (Stefan), and Kersten, M.L. (Martin)

Abstract

Database Cracking is an appealing approach to adaptive indexing: on every range-selection query, the data is partitioned using the supplied predicates as pivots. The core of database cracking is, thus, pivoted partitioning. While pivoted partitioning, like scanning, requires a single pass through the data it tends to have much higher costs due to lower CPU efficiency. In this paper, we conduct an in-depth study of the reasons for the low CPU efficiency of pivoted partitioning. Based on the findings, we develop an optimized version with significantly higher (single-threaded) CPU efficiency. We also develop a number of multi-threaded implementations that are effectively bound by memory bandwidth. Combining all of these optimizations we achieve an implementation that has costs close to or better than an ordinary scan on a variety of systems ranging from low-end (cheaper than $300) desktop machines to high-end (above $60,000) servers.

Published
2014
Full Text
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23. MonetDB Jan2014-SP2 bugfix release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Héman, S. (Sándor), Kyzirakos, K. (Konstantinos), Dinther, M.H.M. (Martin) van, Nedev, D.G. (Dimitar), Alvanaki, F. (Foteini), Cijvat, C.P. (Robin), Sidirourgos, E. (Eleftherios), Ivanova, M.G. (Milena), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Héman, S. (Sándor), Kyzirakos, K. (Konstantinos), Dinther, M.H.M. (Martin) van, Nedev, D.G. (Dimitar), Alvanaki, F. (Foteini), Cijvat, C.P. (Robin), Sidirourgos, E. (Eleftherios), and Ivanova, M.G. (Milena)

Published
2014

24. MonetDB Jan2014 feature release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Sidirourgos, E. (Eleftherios), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Héman, S. (Sándor), Kyzirakos, K. (Konstantinos), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Sidirourgos, E. (Eleftherios), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Héman, S. (Sándor), and Kyzirakos, K. (Konstantinos)

Published
2014

25. MonetDB Oct2014 feature release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Héman, S. (Sándor), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, Sidirourgos, E. (Eleftherios), Ivanova, M.G. (Milena), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Héman, S. (Sándor), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, Sidirourgos, E. (Eleftherios), and Ivanova, M.G. (Milena)

Published
2014

26. MonetDB Oct2014-SP1 bugfix release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Héman, S. (Sándor), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, Sidirourgos, E. (Eleftherios), Ivanova, M.G. (Milena), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Héman, S. (Sándor), Kyzirakos, K. (Konstantinos), Nedev, D.G. (Dimitar), Cijvat, C.P. (Robin), Alvanaki, F. (Foteini), Dinther, M.H.M. (Martin) van, Sidirourgos, E. (Eleftherios), and Ivanova, M.G. (Milena)

Published
2014

27. MonetDB Feb2013 feature release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), and Mühleisen, H.F. (Hannes)

Published
2013

28. MonetDB Feb2013-SP1 bugfix release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Mühleisen, H.F. (Hannes), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), and Mühleisen, H.F. (Hannes)

Published
2013

29. MonetDB Oct2012-SP3 bugfix release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), Mühleisen, H.F. (Hannes), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), and Mühleisen, H.F. (Hannes)

Published
2013

30. MonetDB Jul2012 feature release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), Fundulaki, I., Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), and Fundulaki, I.

Published
2012

31. MonetDB Jul2012-SP1 bugfix release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), Fundulaki, I., Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), and Fundulaki, I.

Published
2012

32. MonetDB Oct2012 feature release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), Fundulaki, I., Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), and Fundulaki, I.

Published
2012

33. MonetDB Apr2012-SP2 bugfix release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Ivanova, M.G. (Milena), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), Fundulaki, I., Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Ivanova, M.G. (Milena), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), and Fundulaki, I.

Published
2012

34. MonetDB Dec2011-SP2 bugfix release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Ivanova, M.G. (Milena), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Ivanova, M.G. (Milena), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), and Meduri, V.V. (Vamsi)

Published
2012

35. MonetDB Oct2012-SP1 bugfix release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), Fundulaki, I., Mühleisen, H.F. (Hannes), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), Fundulaki, I., and Mühleisen, H.F. (Hannes)

Published
2012

36. MonetDB Apr2012 feature release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Ivanova, M.G. (Milena), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), Fundulaki, I., Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Ivanova, M.G. (Milena), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), and Fundulaki, I.

Published
2012

37. Holistic Indexing: Offline, Online and Adaptive Indexing in the Same Kernel

Author

Petraki, E. (Eleni) and Petraki, E. (Eleni)

Abstract

Proper physical design is a momentous issue for the performance of modern database systems and applications. Nowadays, a growing amount of applications require the execution of dynamic and exploratory workloads with unpredictable characteristics that change over time, e.g., social networks, scientific databases and multimed

Published
2012

38. MonetDB Dec2011 feature release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Ivanova, M.G. (Milena), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), Meduri, V.V. (Vamsi), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Ivanova, M.G. (Milena), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kargin, Y. (Yagiz), Gawade, M.M. (Mrunal), and Meduri, V.V. (Vamsi)

Published
2012

39. MonetDB Aug2011-feature release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Ivanova, M.G. (Milena), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Ivanova, M.G. (Milena), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), and Petraki, E. (Eleni)

Published
2011

40. MonetDB Aug2011-SP2 bugfix release

Author

Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Ivanova, M.G. (Milena), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), Sellam, T.H.J. (Thibault), Kersten, M.L. (Martin), Boncz, P.A. (Peter), Nes, N.J. (Niels), Manegold, S. (Stefan), Mullender, K.S. (Sjoerd), Groffen, F.E. (Fabian), Rijke, J.A. (Arjen) de, Zhang, Y. (Ying), Ivanova, M.G. (Milena), Idreos, S. (Stratos), Pereira Goncalves, R.A. (Romulo Antonio), Sidirourgos, E. (Eleftherios), Liarou, E. (Erietta), Pirk, H. (Holger), Pham, M.-D. (Minh-Duc), Scheers, L.H.A. (Bart), Petraki, E. (Eleni), and Sellam, T.H.J. (Thibault)

Published
2011

43. Human Beings and Radiation -- A Review.

Author

Kottou, S., Nikolopoulos, D., Petraki, E., Louizi, A., Argyriou, X., Sevvos, T., and Yannakopoulos, P. H.

Subjects
HUMAN beings, PHYSIOLOGICAL effects of radiation, SOLAR energetic particles, ELECTROMAGNETIC waves, IONIZING radiation, HEALTH risk assessment
Abstract

Humans live and breathe every day in an environment full of natural and artificial radiation. Radiation's nature is energetic particles and/or electromagnetic waves. The damage to tissue from ionizing radiation is being studied decades ago. In contrast, concerns, about the potential health risk associated with unprecedented exposure to non-ionizing radiation, emerge nowadays. Scientists expect objective results to be revealed after few decades of extended use of many low frequency devices or equipment, as well as wireless net and mobile phones. This paper reviews the sources and the most recent results of the effects of radiation, focusing however on the non-ionizing part and, especially, the radiation from radio waves and mobile phones. [ABSTRACT FROM AUTHOR]

Published
2014

44. Stochastic and Self-Organisation Patterns in a 17-Year PM 10 Time Series in Athens, Greece.

Author

Nikolopoulos D, Alam A, Petraki E, Papoutsidakis M, Yannakopoulos P, and Moustris KP

Abstract

This paper utilises statistical and entropy methods for the investigation of a 17-year PM 10 time series recorded from five stations in Athens, Greece, in order to delineate existing stochastic and self-organisation trends. Stochastic patterns are analysed via lumping and sliding, in windows of various lengths. Decreasing trends are found between Windows 1 and 3500-4000, for all stations. Self-organisation is studied through Boltzmann and Tsallis entropy via sliding and symbolic dynamics in selected parts. Several values are below -2 (Boltzmann entropy) and 1.18 (Tsallis entropy) over the Boltzmann constant. A published method is utilised to locate areas for which the PM 10 system is out of stochastic behaviour and, simultaneously, exhibits critical self-organised tendencies. Sixty-six two-month windows are found for various dates. From these, nine are common to at least three different stations. Combining previous publications, two areas are non-stochastic and exhibit, simultaneously, fractal, long-memory and self-organisation patterns through a combination of 15 different fractal and SOC analysis techniques. In these areas, block-entropy (range 0.650-2.924) is significantly lower compared to the remaining areas of non-stochastic but self-organisation trends. It is the first time to utilise entropy analysis for PM 10 series and, importantly, in combination with results from previously published fractal methods.

Published
2021
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45. Network motifs for translator stylometry identification.

Author

El-Fiqi H, Petraki E, and Abbass HA

Subjects
Humans, Algorithms, Authorship, Linguistics
Abstract

Despite the extensive literature investigating stylometry analysis in authorship attribution research, translator stylometry is an understudied research area. The identification of translator stylometry contributes to many fields including education, intellectual property rights and forensic linguistics. In a two stage process, this paper first evaluates the use of existing lexical measures for the translator stylometry problem. Similar to previous research we found that using vocabulary richness in its traditional form as it has been used in the literature could not identify translator stylometry. This encouraged us to design an approach with the aim of identifying the distinctive patterns of a translator by employing network-motifs. Networks motifs are small sub-graphs which aim at capturing the local structure of a complex network. The proposed approach achieved an average accuracy of 83% in three-way classification. These results demonstrate that classic tools based on lexical features can be used for identifying translator stylometry if they get augmented with appropriate non-parametric scaling. Moreover, the use of complex network analysis and network motifs mining provided made it possible to design features that can solve translator stylometry analysis problems., Competing Interests: The authors have declared that no competing interests exist.

Published
2019
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