scholarly journals Restoration of Legacy Parallelism: Transforming Pthreads into Farm and Pipeline Patterns

2021 ◽  
Author(s):  
Vladimir Janjic ◽  
Christopher Brown ◽  
Adam D. Barwell
Keyword(s):  
Ad Hoc ◽  
Parallel Systems ◽  
Parallel Programs ◽  
Business Logic ◽  
Parallel Patterns ◽  
Programming Paradigm ◽  
Pipeline Parallelism ◽  
Restoration Technique ◽  
Parallel Code ◽  
High Level

AbstractParallel patterns are a high-level programming paradigm that enables non-experts in parallelism to develop structured parallel programs that are maintainable, adaptive, and portable whilst achieving good performance on a variety of parallel systems. However, there still exists a large base of legacy-parallel code developed using ad-hoc methods and incorporating low-level parallel/concurrency libraries such as pthreads without any parallel patterns in the fundamental design. This code would benefit from being restructured and rewritten into pattern-based code. However, the process of rewriting the code is laborious and error-prone, due to typical concurrency and pthreading code being closely intertwined throughout the business logic of the program. In this paper, we present a new software restoration methodology, to transform legacy-parallel programs implemented using pthreads into structured farm and pipeline patterned equivalents. We demonstrate our restoration technique on a number of benchmarks, allowing the introduction of patterned farm and pipeline parallelism in the resulting code; we record improvements in cyclomatic complexity and speedups on a number of representative benchmarks.

Countering Threats

2014 ◽  
Vol 4 (2) ◽  
pp. 35-45
Author(s):  
Margarita Jaitner
Keyword(s):  
Social Media ◽  
Law Enforcement ◽  
Ad Hoc ◽  
Physical Violence ◽  
Deep Understanding ◽  
Current Status ◽  
Mobile Web ◽  
Use Of Social Media ◽  
Legal Frameworks ◽  
High Level

The increased adoption of social media has presented security and law enforcement authorities with significant new challenges. For example, the Swedish Security Service (SÄPO) asserts that a large proportion of radicalization takes place in open fora online. Still, approaches to contain social media-driven challenges to security, particularly in democratic societies, remain little explored. Nonetheless, this type of knowledge may become relevant in European countries in the near future: Amongst other factors, the challenging economic situation has resulted in increased public discontent leading to emergence or manifestation of groups that seek to challenge the existing policies by almost any means. Use of social media multiplies the number of vectors that need law enforcement attention. First, a high level of social media adaption allows groups to reach and attract a wider audience. Unlike previously, many groups today consist of a large but very loosely connected network. This lack of cohesion can present a challenge for authorities, to identify emerging key actors and assess threat levels. Second, a high level of mobile web penetration has allowed groups to ad-hoc organize, amend plans and redirect physical activities. Third, the tool social media is as not exclusive to potential perpetrators of unlawful action, but is as well available to law enforcement authorities. Yet, efficient utilization of social media requires a deep understanding of its nature and a well-crafted, comprehensive approach. Acknowledging the broad functionality of social media, as well as its current status in the society, this article describes a model process for security authorities and law enforcement work with social media in general and security services work in particular. The process is cyclic and largely modular. It provides a set of goals and tasks for each stage of a potential event, rather than fixed activities. This allows authorities to adapt the process to individual legal frameworks and organization setups. The approach behind the process is holistic where social media is regarded as both source and destination of information. Ultimately, the process aims at efficiently and effectively mitigating the risk of virtual and physical violence.

A Game Theoretic Approach to Thwart Selfishness Attack in MANET

2012 ◽  
Vol 433-440 ◽  
pp. 3944-3948
Author(s):  
Prasenjit Choudhury ◽  
Anita Pal ◽  
Anjali Gupchup ◽  
Krati Budholiya ◽  
Alokparna Banerjee
Keyword(s):  
Ad Hoc ◽  
Theoretic Approach ◽  
Selfish Nodes ◽  
Selfish Behavior ◽  
Mutual Cooperation ◽  
Game Theoretic ◽  
Hoc Networks ◽  
High Level ◽  
The Impact ◽  
Game Theoretic Approach

Ad-hoc networks are attractive, since they can provide a high level of connectivity without the need of a fixed infrastructure. Nodes that are not within the same transmission range communicate through multi-hops, where intermediate nodes act as relays. Mutual cooperation of all the participating nodes is necessary for proper operation of MANET. However, nodes in MANET being battery-constrained, they tend to behave selfishly while forwarding packets. In this paper, we have investigated the security of MANET AODV routing protocol by identifying the impact of selfish nodes on it. It was observed that due to the presence of selfish nodes, packet loss in the network increases and the performance of MANET degrades significantly. Finally a game theoretic approach is used to mitigate the selfishness attack. All the nodes in MANET should cooperate among themselves to thwart the selfish behavior of attacker nodes.

scholarly journals Reading the bed morphology of a mountain stream: a geomorphometric study on high-resolution topographic data

2010 ◽  
Vol 14 (2) ◽  
pp. 393-405 ◽  
Author(s):  
S. Trevisani ◽  
M. Cavalli ◽  
L. Marchi
Keyword(s):  
High Resolution ◽  
Ad Hoc ◽  
Flow Direction ◽  
Spatial Scales ◽  
Mountain Stream ◽  
Topographic Data ◽  
The Difference ◽  
Morphological Differences ◽  
High Level ◽  
Local Anomalies

Abstract. High-resolution topographic data expand the potential of quantitative analysis of the earth surface, improving the interpretation of geomorphic processes. In particular, the morphologies of the channel beds of mountain streams, which are characterised by strong spatial variability, can be analysed much more effectively with this type of data. In this study, we analysed the aerial LiDAR topographic data of a headwater stream, the Rio Cordon (watershed area: 5 km2), located in the Dolomites (north-eastern Italy). The morphology of the channel bed of Rio Cordon is characterised by alternating step pools, cascades, and rapids with steps. We analysed the streambed morphology by means of ad hoc developed morphometric indices, capable of highlighting morphological features at a high level of spatial resolution. To perform the analysis and the data interpolation, we carried out a channel-oriented coordinate transformation. In the new coordinate system, the calculation of morphometric indices in directions along and transverse to the flow direction is straightforward. Three geomorphometric indices were developed and applied as follows: a slope index computed on the whole width of the channel bed, directional variograms computed along the flow direction and perpendicular to it, and local anomalies, calculated as the difference between directional variograms at different spatial scales. Directional variograms in the flow direction and local anomalies have proven to be effective at recognising morphologic units, such as steps, pools and clusters of large boulders. At the spatial scale of channel reaches, these indices have demonstrated a satisfactory capability to outline patterns associated with boulder cascades and rapids with steps, whereas they did not clearly differentiate between morphologies with less marked morphological differences, such as step pools and cascades.

scholarly journals Establishing an ad hoc COVID-19 mortality surveillance during the first epidemic wave in Belgium, 1 March to 21 June 2020

2021 ◽  
Vol 26 (48) ◽  
Author(s):  
Françoise Renard ◽  
Aline Scohy ◽  
Johan Van der Heyden ◽  
Ilse Peeters ◽  
Sara Dequeker ◽  
...  
Keyword(s):  
Ad Hoc ◽  
Participation Rate ◽  
Term Care ◽  
Data Flows ◽  
Care Facilities ◽  
Definition Of ◽  
High Level ◽  
Mortality Surveillance ◽  
Related Mortality

Background COVID-19-related mortality in Belgium has drawn attention for two reasons: its high level, and a good completeness in reporting of deaths. An ad hoc surveillance was established to register COVID-19 death numbers in hospitals, long-term care facilities (LTCF) and the community. Belgium adopted broad inclusion criteria for the COVID-19 death notifications, also including possible cases, resulting in a robust correlation between COVID-19 and all-cause mortality. Aim To document and assess the COVID-19 mortality surveillance in Belgium. Methods We described the content and data flows of the registration and we assessed the situation as of 21 June 2020, 103 days after the first death attributable to COVID-19 in Belgium. We calculated the participation rate, the notification delay, the percentage of error detected, and the results of additional investigations. Results The participation rate was 100% for hospitals and 83% for nursing homes. Of all deaths, 85% were recorded within 2 calendar days: 11% within the same day, 41% after 1 day and 33% after 2 days, with a quicker notification in hospitals than in LTCF. Corrections of detected errors reduced the death toll by 5%. Conclusion Belgium implemented a rather complete surveillance of COVID-19 mortality, on account of a rapid investment of the hospitals and LTCF. LTCF could build on past experience of previous surveys and surveillance activities. The adoption of an extended definition of ‘COVID-19-related deaths’ in a context of limited testing capacity has provided timely information about the severity of the epidemic.

scholarly journals Interaction with the User in the SAPFOR System

2021 ◽  
Vol 24 (1) ◽  
pp. 157-183
Author(s):  
Никита Андреевич Катаев
Keyword(s):  
Parallel Programming ◽  
Program Transformation ◽  
Heterogeneous Computing ◽  
Programming Model ◽  
Parallel Programs ◽  
Parallel Program ◽  
Program Parallelization ◽  
Parallel Programming Model ◽  
The One ◽  
High Level

Automation of parallel programming is important at any stage of parallel program development. These stages include profiling of the original program, program transformation, which allows us to achieve higher performance after program parallelization, and, finally, construction and optimization of the parallel program. It is also important to choose a suitable parallel programming model to express parallelism available in a program. On the one hand, the parallel programming model should be capable to map the parallel program to a variety of existing hardware resources. On the other hand, it should simplify the development of the assistant tools and it should allow the user to explore the parallel program the assistant tools generate in a semi-automatic way. The SAPFOR (System FOR Automated Parallelization) system combines various approaches to automation of parallel programming. Moreover, it allows the user to guide the parallelization if necessary. SAPFOR produces parallel programs according to the high-level DVMH parallel programming model which simplify the development of efficient parallel programs for heterogeneous computing clusters. This paper focuses on the approach to semi-automatic parallel programming, which SAPFOR implements. We discuss the architecture of the system and present the interactive subsystem which is useful to guide the SAPFOR through program parallelization. We used the interactive subsystem to parallelize programs from the NAS Parallel Benchmarks in a semi-automatic way. Finally, we compare the performance of manually written parallel programs with programs the SAPFOR system builds.

scholarly journals Monitoring System-Based Flying IoT in Public Health and Sports Using Ant-Enabled Energy-Aware Routing

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Inam Ullah Khan ◽  
Muhammad Abul Hassan ◽  
Mohammad Dahman Alshehri ◽  
Mohammed Abdulaziz Ikram ◽  
Hasan J. Alyamani ◽  
...  
Keyword(s):  
Ad Hoc ◽  
Residual Energy ◽  
Base Station ◽  
Rapid Decline ◽  
Energy Aware ◽  
Remote Communication ◽  
Aerial Vehicles ◽  
Wide Range ◽  
Hoc Networks ◽  
High Level

In recent decades, the Internet of flying networks has made significant progress. Several aerial vehicles communicate with one another to form flying ad hoc networks. Unmanned aerial vehicles perform a wide range of tasks that make life easier for humans. However, due to the high frequency of mobile flying vehicles, network problems such as packet loss, latency, and perhaps disrupted channel links arise, affecting data delivery. The use of UAV-enabled IoT in sports has changed the dynamics of tracking and working on player safety. WBAN can be merged with aerial vehicles to collect data regarding health and transfer it to a base station. Furthermore, the unbalanced energy usage of flying things will result in earlier mission failure and a rapid decline in network lifespan. This study describes the use of each UAV’s residual energy level to ensure a high level of safety using an ant-based routing technique called AntHocNet. In health care, the use of IoT-assisted aerial vehicles would increase operational performance, surveillance, and automation optimization to provide a smart application of flying IoT. Apart from that, aerial vehicles can be used in remote communication for treatment, medical equipment distribution, and telementoring. While comparing routing algorithms, simulation findings indicate that the proposed ant-based routing protocol is optimal.

A user‐oriented interface for generalised informetric analysis based on applying advanced data modelling techniques

2000 ◽  
Vol 56 (3) ◽  
pp. 250-278 ◽  
Author(s):  
Kalervo Järvelin ◽  
Peter Ingwersen ◽  
Timo Niemi
Keyword(s):  
Ad Hoc ◽  
Impact Factors ◽  
Data Modelling ◽  
Complex Objects ◽  
Bibliographic Data ◽  
Modelling Techniques ◽  
General Data ◽  
Advanced Analysis ◽  
Data Restructuring ◽  
High Level

This article presents a novel user‐oriented interface for generalised informetric analysis and demonstrates how informetric calculations can easily and declaratively be specified through advanced data modelling techniques. The interface is declarative and at a high level. Therefore it is easy to use, flexible and extensible. It enables end users to perform basic informetric ad hoc calculations easily and often with much less effort than in contemporary online retrieval systems. It also provides several fruitful generalisations of typical informetric measurements like impact factors. These are based on substituting traditional foci of analysis, for instance journals, by other object types, such as authors, organisations or countries. In the interface, bibliographic data are modelled as complex objects (non‐first normal form relations) and terminological and citation networks involving transitive relationships are modelled as binary relations for deductive processing. The interface is flexible, because it makes it easy to switch focus between various object types for informetric calculations, e.g. from authors to institutions. Moreover, it is demonstrated that all informetric data can easily be broken down by criteria that foster advanced analysis, e.g. by years or content‐bearing attributes. Such modelling allows flexible data aggregation along many dimensions. These salient features emerge from the query interface‘s general data restructuring and aggregation capabilities combined with transitive processing capabilities. The features are illustrated by means of sample queries and results in the article.

Developing Web3D Tools for Promoting the European Heritage

2010 ◽  
pp. 194-208 ◽  
Author(s):  
Francesco Bellotti ◽  
Riccardo Berta ◽  
Alessandro De Gloria ◽  
Ludovica Primavera
Keyword(s):  
Ad Hoc ◽  
Simple Game ◽  
Online Games ◽  
Level Of Detail ◽  
Game Engine ◽  
Main Concept ◽  
Multiplayer Online Games ◽  
Covered Area ◽  
European Heritage ◽  
High Level

Virtual reality environments are ever more going online. This trend, opened by videogames, will open new important opportunities to enhance cultural tourism, given the possibility of creating compelling virtual adventures set in the context of artistic and natural beauties. The authors are exploring these challenges in the context of the Travel in Europe (TiE) project, and developing tools to build enriched virtual environments where the player could explore faithfully reconstructed places and live there information-rich, contextualized experiences. The TiE architecture is based on a state-of-the-art commercial game engine, with massive multiplayer online games (MMOG) facilities that support access to multiple concurrent users, plus ad-hoc designed modules. The 3D model is completely geo-referenced. In each covered area, a few points-of-interest (POIs) are implemented. These buildings are rigorously reconstructed at a high level of detail. The textures for the rest of the palaces are built dynamically by the TiE system using a statistical template-based algorithm that exploits local characterizations of common architectonic elements. The TiE virtual world is enriched by geo-localized, contextualized MicroGames (mGs). mGs are simple, short games that focus the player’s attention on a particular item that is found during exploration of the 3D world. mGs are typically taken from well known simple game models, such as Puzzle, MemoryGame, and FindTheWrongDetails. The main concept that underpins mGs is that, they should be intuitive and easy to play, so that the player can focus on the contents rather than on learning how to play. Preliminary informal tests have suggested that the approach is valid and that the enriched 3D environment supports the contextualized promotion of artifacts, products and services, which is an important growing demand from institutions and enterprises that want to valorize the resources of a territory.

scholarly journals A unified accretion-ejection paradigm for black hole X-ray binaries

2019 ◽  
Vol 626 ◽  
pp. A115 ◽  
Author(s):  
G. Marcel ◽  
J. Ferreira ◽  
M. Clavel ◽  
P.-O. Petrucci ◽  
J. Malzac ◽  
...  
Keyword(s):  
Radio Emission ◽  
Accretion Disk ◽  
Ad Hoc ◽  
Emission Model ◽  
X Rays ◽  
Temperature Plasma ◽  
X Ray ◽  
Fitting Procedure ◽  
High Level ◽  
X Ray Binaries

Context. Transient X-ray binaries (XrB) exhibit very different spectral shapes during their evolution. In luminosity-color diagrams, their behavior in X-rays forms q-shaped cycles that remain unexplained. In Paper I, we proposed a framework where the innermost regions of the accretion disk evolve as a response to variations imposed in the outer regions. These variations lead not only to modifications of the inner disk accretion rate ṁin, but also to the evolution of the transition radius rJ between two disk regions. The outermost region is a standard accretion disk (SAD), whereas the innermost region is a jet-emitting disk (JED) where all the disk angular momentum is carried away vertically by two self-confined jets. Aims. In the previous papers of this series, it has been shown that such a JED–SAD disk configuration could reproduce the typical spectral (radio and X-rays) properties of the five canonical XrB states. The aim of this paper is now to replicate all X-ray spectra and radio emission observed during the 2010–2011 outburst of the archetypal object GX 339-4. Methods. We used the two-temperature plasma code presented in two previous papers (Papers II and III) and designed an automatic ad hoc fitting procedure that for any given date calculates the required disk parameters (ṁin,rJ) that fit the observed X-ray spectrum best. We used X-ray data in the 3–40 keV (RXTE/PCA) spread over 438 days of the outburst, together with 35 radio observations at 9 GHz (ATCA) dispersed within the same cycle. Results. We obtain the time distributions of ṁin(t) and rJ(t) that uniquely reproduce the X-ray luminosity and the spectral shape of the whole cycle. In the classical self-absorbed jet synchrotron emission model, the JED–SAD configuration also reproduces the radio properties very satisfactorily, in particular, the switch-off and -on events and the radio-X-ray correlation. Although the model is simplistic and some parts of the evolution still need to be refined, this is to our knowledge the first time that an outburst cycle is reproduced with such a high level of detail. Conclusions. Within the JED–SAD framework, radio and X-rays are so intimately linked that radio emission can be used to constrain the underlying disk configuration, in particular, during faint hard states. If this result is confirmed using other outbursts from GX 339-4 or other X-ray binaries, then radio could be indeed used as another means to indirectly probe disk physics.

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