Lightweight Ones Research Articles

Finding Impossible Differentials in ARX Ciphers under Weak Keys

Impossible differential cryptanalysis is very important in the field of symmetric ciphers. Currently, there are many automatic search approaches to find impossible differentials. However, these methods have two underlying assumptions: Markov cipher assumption and key independence assumption. Actually, these two assumptions are not true in ARX ciphers, especially lightweight ones. In this paper, we study the impossible differentials in ARX cipher under weak keys for the first time. Firstly, we propose several accurate difference propagation properties on consecutive two and three modular additions. Then, these properties are applied to four typical local constructions composed of two consecutive modular additions, two modular additions with a rotation operation, xoring secret key or constant in the middle, to find impossible differentials under weak keys or special constants. What’s more, we propose a more accurate difference propagation property on three consecutive modular additions. It can be used to find impossible differentials on more complex local constructions under weak keys or special constants. In practical ciphers, these impossible differentials on local constructions can be used to find contradictions. Lastly, combining our new findings with traditional automatic search methods for impossible differentials, we propose a framework to find impossible differentials in ARX ciphers under weak keys. As applications, we apply the framework to SPECK-32/64, LEA and CHAM-64/128. As a result, we find two 8-round impossible differentials for SPECK-32/64 under 260 weak keys, and one 11-round impossible differential for LEA under 2k−1 weak keys, where k is the key size. These impossible differentials can start from any round. Furthermore, we find two 22-round impossible differentials for CHAM-64/128 under 2127 weak keys starting from certain rounds. As far as we know, all these impossible differentials are longer than previous ones.

Numerical solutions to linear transfer problems of polarized radiation

Context. A relevant class of radiative transfer problems for polarized radiation is linear, or can be linearized, and can thus be reframed as linear systems once discretized. In this context, depending on the considered physical models, there are both highly coupled and computationally expensive problems, for which state-of-the-art iterative methods struggle to converge, and lightweight ones, for which solutions can be obtained efficiently. Aims. This work aims to exploit lightweight physical models as preconditioners for iterative solution strategies to obtain accurate and fast solutions for more complex problems. Methods. We considered a highly coupled linear transfer problem for polarized radiation, which we solved iteratively using a matrix-free generalized minimal residual (GMRES) method. Different preconditioners and initial guesses, designed in a physics-based framework, are proposed and analyzed. The action of preconditioners was also computed by applying GMRES. The overall approach thus consists of two nested GMRES iterations, one for the original problem and one for its lightweight version. As a benchmark, we considered the modeling of the intensity and polarization of the solar Ca I 4227 Å line, the Sr II 4077 Å line, and the Mg II h&k lines in a semi-empirical 1D atmospheric model, accounting for partial frequency redistribution effects in scattering processes and considering a general angle-dependent treatment. Results. Numerical experiments show that using tailored preconditioners based on simplified models of the considered problem has a noticeable impact, reducing the number of iterations to convergence by a factor of 10–20. Conclusions. By designing efficient preconditioners in a physics-based context, it is possible to significantly improve the convergence of iterative processes, obtaining fast and accurate numerical solutions to the considered problems. The presented approach is general, requiring only the selection of an appropriate lightweight model, and can be applied to a larger class of radiative transfer problems in combination with arbitrary iterative procedures.

Changes in healthcare utilisation during implementation of remote atrial fibrillation management: TeleCheck-AF project.

To evaluate changes in healthcare utilisation and comprehensive packages of care activities and procedures (referred in the Netherlands to as 'diagnose-behandelcombinatie (DBC) care products) during the implementation of the TeleCheck-AF approach (teleconsultation supported by app-based heart rate/rhythm monitoring) in aDutch atrial fibrillation (AF) clinic. In the Maastricht University Medical Centre+ AF Clinic, data on healthcare utilisation and DBC care products for patients consulted by both aconventional approach in 2019 and the TeleCheck-AF approach in 2020 were analysed. Apatient experience survey was performed. Thirty-seven patients (median age 68years; 40% women) were analysed. With the conventional approach, 35face-to-face consultations and 0teleconsultations were conducted. After the implementation of TeleCheck-AF, the number of face-to-face consultations dropped by 80% (p < 0.001) and teleconsultations increased to 45 (p < 0.001). While 42electrocardiograms (ECGs) and 25Holter ECGs or echocardiograms were recorded when using the conventional approach, the number of ECGs decreased by 71% (p < 0.001) and Holter ECGs or echocardiograms by 72% (p < 0.001) with the TeleCheck-AF approach. The emergency department patient presentations showed no statistically significant change (p = 0.33). Overall, 57% of medium-weight DBC care products were changed to light-weight ones during implementation of the TeleCheck-AF approach. Patient satisfaction with the TeleCheck-AF approach was high. The implementation of TeleCheck-AF led to achange in healthcare utilisation, achange from medium-weight to light-weight DBC care products and areduction in patient burden. These results created the basis for anew reimbursement code for the TeleCheck-AF approach in the Netherlands.

Parameter Identification of Li-ion Batteries: A Comparative Study

Lithium-ion batteries are crucial building stones in many applications. Therefore, modeling their behavior has become necessary in numerous fields, including heavyweight ones such as electric vehicles and plug-in hybrid electric vehicles, as well as lightweight ones like sensors and actuators. Generic models are in great demand for modeling the current change over time in real-time applications. This paper proposes seven dynamic models to simulate the behavior of lithium-ion batteries discharging. This was achieved using NASA room temperature random walk discharging datasets. The efficacy of these models in fitting different time-domain responses was tested through parameter identification with the Marine Predator Algorithm (MPA). In addition, each model’s term’s impact was analyzed to understand its effect on the fitted curve. The proposed models show an average absolute normalized error as low as 0.0057.

A strength and deformation model for prestressed lightweight concrete slabs under two-way shear

Prestressed concrete slabs (PCS) are one of the top choices in many applications, which is due to their significantly improved performance compared to conventional normal-weight concrete slabs (NCS). However, very limited models exist for the two-way shear behavior of PCS, in particular, lightweight ones (PLCS). In this study, a two-way shear mechanical behavior model is developed for PCS, that accounts for all effective parameters and capable of predicting both strength and deformation. An experimental database of PCS was compiled from the literature with emphasis on lightweight concrete. A mechanical model developed by the author for lightweight concrete slabs (LCS) was adapted and modified in order to include the effect of prestressing in terms of the following components: (1) the membrane compression stress; (2) the prestressing eccentricity; and (3) the prestressing vertical component. The extended model was used to predict the behavior of PLCS and prestressed normal-weight concrete slabs (PNCS), which was compared to that using selected design codes and models. The model predicted the rotation accurately and consistently compared to the experimentally measured rotation. The strength predicted using the proposed model was better than existing ones concerning experimentally measured strength, yet it was found to be reasonably safe. However, conclusions are limited to the experimental database.

Implementation of Lightweight Convolutional Neural Networks via Layer-Wise Differentiable Compression.

Convolutional neural networks (CNNs) have achieved significant breakthroughs in various domains, such as natural language processing (NLP), and computer vision. However, performance improvement is often accompanied by large model size and computation costs, which make it not suitable for resource-constrained devices. Consequently, there is an urgent need to compress CNNs, so as to reduce model size and computation costs. This paper proposes a layer-wise differentiable compression (LWDC) algorithm for compressing CNNs structurally. A differentiable selection operator OS is embedded in the model to compress and train the model simultaneously by gradient descent in one go. Instead of pruning parameters from redundant operators by contrast to most of the existing methods, our method replaces the original bulky operators with more lightweight ones directly, which only needs to specify the set of lightweight operators and the regularization factor in advance, rather than the compression rate for each layer. The compressed model produced by our method is generic and does not need any special hardware/software support. Experimental results on CIFAR-10, CIFAR-100 and ImageNet have demonstrated the effectiveness of our method. LWDC obtains more significant compression than state-of-the-art methods in most cases, while having lower performance degradation. The impact of lightweight operators and regularization factor on the compression rate and accuracy also is evaluated.

Construction of lightweight involutory MDS matrices

In this paper, we propose an efficient method to find lightweight involutory MDS matrices. To obtain involutory matrices, we give a necessary and sufficient condition for judging the involutory MDS property and propose a search method. For the $$n\times n$$ involutory MDS matrices over $${\mathbb {F}}_{2^m}$$ , the amount of computation is reduced from $$2^{mn^2}$$ to $$2^{(mn^2)/2}$$ . Especially, we can exhaustively search for involutory MDS matrices when $$n=4$$ , and for larger n, we add additional restrictions to reduce the search range. As for finding lightweight ones, we use the permutation-equivalent class to extend the input such that the efficiency of the heuristic designed by Xiang et al. can be improved. Applying our method, we obtain a class of $$16\times 16$$ binary MDS matrices with branch number 5, which can be implemented with only 35 XOR gates. The results even reach the same implementation cost as the lightest non-involutory MDS matrix up to now. Concerning lightweight binary matrices with order 32, it is hard to obtain optimal results through search. Hence, we construct $$32\times 32$$ matrices with the lightweight $$16 \times 16$$ matrices that we found. In this way, we obtain two classes of $$ 4 \times 4 $$ involutory MDS matrices whose entries are $$ 8 \times 8 $$ binary matrices with 70 XOR gates while the previous lightest matrices with the same size cost 78 XOR gates. Moreover, we also generalize our search method to general cases and it is provable that the approach is feasible for MDS matrices of order 6 and 8 to achieve efficient search.

Occupational safety and health in traditional date palm works.

Date palm is mostly cultivated in Western Asia and North Africa and is the main wealth for the people of these regions. Traditional date palm crown access via manual climbing, as the main activity in date fruit production, suffers from occupational hazards. Mitigation of these problems through interventions or new designs initially needs to complete knowledge of safety and health aspects and relationships between them and characters of date palm climbers. This study provided detailed information about this concern. A questionnaire consisting of personal, operational, safety, satisfaction, financial and ergonomic demographics was used for data collection. 117 climbers participated in the study. Nonparametric correlations using Spearman's coefficient and logistic regressions investigated the linkage between characters obtained by the questionnaire. The annual mortality rate of falls from height was calculated by 3.4 per one thousand men. Fall was a major challenge in traditional date palm crown access and its rate was highly greater in comparison with the estimation of International Labor Office (ILO) about fatal agricultural injuries. Safety and health condition was the main contributing factor in the status of date palm climbing and was significantly linked to job satisfaction. Safety risk-taking and non-awareness of technology had a significant linkage with together (r = - 0.195, p = 0.035). Safety risk-taking, also, had significant correlations with discomfort in back (r = - 0.201, p = 0.030). Regressions showed heavier climbers (> 75kg) were expected about 4.3 (1/0.230) times than more lightweight ones to have an upper leg discomfort with high severity relative to low severity (p = 0.018). Obesity, senescence, and awareness of technology as three personal characteristics of climbers need to be addressed. Future strategies are required to improve the safety condition of climbing and manage the workforces as well as governmental decision making to address the financial aspects of climbers for sustainable date production and reduction in reasons causing unemployment. Considering current status and modification of the present tool and equipment is recommended.

Assessment of spatial rigidity and stability of a building when replacing reinforced concrete ribbed plates with lightweight coating

The tasks of restoring and ensuring the normalized parameters of the operational qualities for building structures, as well as their further safe operation in the development of capital repair and reconstruction projects, in most cases include the replacement of existing heavy coating structures with alternative lightweight ones that meet the regulated modern standards.

Comparisons of Motor Actions and Biomechanical Assessments of Judo Techniques Between Female Weight Categories

This study aimed to perform motor action and biomechanical analysis of techniques in female judo athletes separated by weight categories of 638 female bouts (103 extra lightweight <48 kg, 140 half lightweight 48>52 kg, 65 lightweight 52>57 kg, 73 half middleweight 57>63 kg, 77 middleweight 63>70 kg, 80 half heavyweight 70>78 kg and 60 heavyweight >78 kg). All bouts were analyzed following the phases of approach, gripping, defensive action, attack, also biomechanical analysis of techniques and groundwork was performed (p ≤ .05). Results indicated that lightweight athletes presented lower attempts to grip, right collar grip and left collar grip frequencies than other categories. Extra lightweight judokas presented lower right back grip and left back and sleeve grip frequencies as well as lower occurrence of techniques with arm and leg lever scored than half lightweight athletes, while half lightweight athletes demonstrated higher frequency of techniques with waist lever variable scored than lightweight ones. These findings should be considered for training prescription.

Life-Cycle and Energy Assessment of Automotive Component Manufacturing: The Dilemma Between Aluminum and Cast Iron

Considering the manufacturing of automotive components, there exists a dilemma around the substitution of traditional cast iron (CI) with lighter metals. Currently, aluminum alloys, being lighter compared to traditional materials, are considered as a more environmentally friendly solution. However, the energy required for the extraction of the primary materials and manufacturing of components is usually not taken into account in this debate. In this study, an extensive literature review was performed to estimate the overall energy required for the manufacturing of an engine cylinder block using (a) cast iron and (b) aluminum alloys. Moreover, data from over 100 automotive companies, ranging from mining companies to consultancy firms, were collected in order to support the soundness of this investigation. The environmental impact of the manufacturing of engine blocks made of these materials is presented with respect to the energy burden; the “cradle-to-grave approach” was implemented to take into account the energy input of each stage of the component life cycle starting from the resource extraction and reaching to the end-of-life processing stage. Our results indicate that, although aluminum components contribute toward reduced fuel consumption during their use phase, the vehicle distance needed to be covered in order to compensate for the up-front energy consumption related to the primary material production and manufacturing phases is very high. Thus, the substitution of traditional materials with lightweight ones in the automotive industry should be very thoughtfully evaluated.

Evaluation of internal curing effects on concrete

The objective of the present research was the evaluation of some fresh and hardenedstate properties of concretes, in which coarse aggregates were partially replaced by lightweight ones previously saturated, in percentages of 15% and 25 %. The lightweight aggregates were calcined clays and crushed clay bricks. In parallel, the effect of an internal curing agent composed of superabsorbent polymers (SAP) was evaluated. The properties evaluated in the fresh and hardenedstate of concretes with a/c of 0,30 were: slum, air content, density, compression resistance, modulus of elasticity, initial superficial absorption and chlorine resistance. Results showed the efficiency of crushed clay bricks as internal curing, as well as the need for deeper research on the use of the evaluated lightweight aggregate as internal curing aggregate in concrete. Results indicate that the crushed clay bricks and the internal curing agent fulfill the behavior expected, in terms of strength and durability. However, the evaluated lightweight aggregate produces a reduction in the resistance and durability of the concrete. The observed behavior in strength and durability is especially variable for the age of 180 days, compared with conventional concretes.

A Unified Framework for Bug Report Assignment

It is typically a manual, time-consuming, and tedious task of assigning bug reports to individual developers. Although some machine learning techniques are adopted to alleviate this dilemma, they are mainly focused on the open source projects, which use traditional repositories such as Bugzilla to manage their bug reports. With the boom of the mobile Internet, some new requirements and methods of software testing are emerging, especially the crowdsourced testing. Unlike the traditional channels, whose bug reports are often heavyweight, which means their bug reports are standardized with detailed attribute localization, bug reports tend to be lightweight in the context of crowdsourced testing. To exploit the differences of the bug reports assignment in the new settings, a unified bug reports assignment framework is proposed in this paper. This framework is capable of handling both the traditional heavyweight bug reports and the lightweight ones by (i) first preprocessing the bug reports and feature selections, (ii) then tuning the parameters that indicate the ratios of choosing different methods to vectorize bug reports, (iii) and finally applying classification algorithms to assign bug reports. Extensive experiments are conducted on three datasets to evaluate the proposed framework. The results indicate the applicability of the proposed framework, and also reveal the differences of bug report assignment between traditional repositories and crowdsourced ones.

Recycled Plastic and Cork Waste for Structural Lightweight Concrete Production

The use of waste materials as lightweight aggregates in concrete is highly recommended in seismic risk areas and environmentally recommended. However, reaching the strength needed for the concrete to be used structurally may be challenging. In this study four dosages were assayed: the first two-specimen had high cement content (550 and 700 kg/m3 respectively), Nanosilica, fly ash and superplasticizer. These samples were high performance, reaching a strength of 100 MPa at 90 days. The other two mixtures were identical but replaced 48% of the aggregates with recycled lightweight aggregates (30% polypropylene, 18.5% cork). To estimate its strength and durability the mixtures were subjected to several tests. Compression strength, elasticity modulus, mercury intrusion porosimetry, carbonation, attack by chlorides, and penetration of water under pressure were analyzed. The compression strength and density of the lightweight mixtures were reduced 68% and 19% respectively; nonetheless, both retained valid levels for structural use (over 30 MPa at 90 days). Results, such as the total porosity between 9.83% and 17.75% or the chloride ion penetration between 8.6 and 5.9 mm, suggest that the durability of these concretes, including the lightweight ones, is bound to be very high thanks to a very low porosity and high resistance to chemical attacks.

Data Reduction Through Increased Data Utilization in Chemical Dynamics Simulations

Abstract Many scientific applications consist of heavy computational and analysis workload on data, and often require producing intermediate data for ongoing calculations. For instance, chemical dynamics simulations are known as heavy workload applications in terms of calculation in many aspects. There is a strong desire of seeking a solution to minimize expensive calculations by replacing them with light-weight ones. VENUS is one of these chemical dynamic simulation software packages known as classical chemical dynamics simulation, with scalar executing code and heavy calculation process. In this research, we introduce an innovative approximation method by storing, managing, and leveraging intermediate data (results) in order to speed up expensive calculations. The key idea is a newly introduced data interpolation method that leverages data points from previous calculations. The newly proposed method is a general approach that can be applied to a variety of scientific applications and disciplines. In this research, we focus on chemical dynamics simulations and the VENUS code and have developed a prototype of the data interpolation method for reduced computations. The proposed computation reduction method through increased data re-use can increase the efficiency and productivity of scientific simulations, thus can have an impact on scientific discovery powered by high performance computing simulations.

Rule change and Olympic judo scores, penalties and match duration

In judo, between 2009 and 2013, many changes were added, especially after London 2012 Olympics to promote “positive” actions/score instead of “negative” actions/penalties. This study compared the total match duration, frequency of scores (ippon, wazari, yuko) and penalties (shido) between Rio 2016 and London 2012 (before and after rules change), considering weight categories and competition phases. Data from 470 male athletes and 307 female athletes who disputed, respectively, 1022 and 698 matches in both Olympic Games were analysed. Three-way ANOVA was used to compare sexes, weight categories, Olympic Games edition, with Tukey test as post hoc. The association between Olympic Games edition and percentage of matches without any score was tested via Chi-square and Cramer’s – V effect size was used. Significance level was set at 5%. Eta squared (η2) was used as effect size. Results (Rio 2016 vs. London 2012) suggest in no change in ippon and wazari scores, while decreasing the number of yuko and increasing the number of penalties. Females scored more yuko and received less penalties than males. Females matches in Rio were shorter than matches for all other groups. For scores and penalties, no difference was found concerning weight categories, but half-heavyweight matches were shorter than lightweight ones.

Dune sand and pumice impact on mechanical and thermal lightweight concrete properties

This paper consists of substituting an appropriate fraction of natural aggregates with lightweight ones composite concrete development such as pumice which is found in volcanic sediments, the advantage of using lightweight concrete is to reduce the dead-weight; its light weight gives a better thermal insulating power in comparison to traditional materials, given the volume of air they contain. This work comes also within an economic framework, given the abundance of sand dunes, particularly in the Sahara to possibly replace the coastal sand dunes. High cement proportion is required to obtain high resistance levels, hence lightweight concrete performance can be dramatically improved through a consistent dosing of fines. Workability is improved by increasing Water/Cement ratio; it also relies on fine nature and dosing when W/C ratio is fixed. On that point, the substitution of dune sand in lightweight concrete could obviously be of great benefit. This advantage allows us to exploit natural resources and gives us the ability to produce at lower costs and provide concrete with rheology and long term strength. The simplest approach consists of measuring each parameter impact: collapse, mechanical resistance and heat transfer properties, through 16×32cm cylindrical probes. Pumice has a major influence on fresh lightweight concrete; it should stay damp before use to avoid quick slump loss. Mixture’s workability was affected by a substantial sand content. The dune sand substitution with the quarry sand increased the resistance by the filling of the voids within the aggregates, thus compressive strength of concrete type has spectacularly increased. The testing behaviour and simulations performed on cylindrical probes of 16×32cm have shown that dehydration of the heated concrete causes a decrease of Young's modulus (softening) and mechanic resistance drop (decohesion) in compression causing degradation of the paste aggregate interface, and may cause cement matrix micro-cracks.

Privacy of Public Data

The construct of an information dichotomy has played a defining role in regulating privacy: information deemed private or sensitive typically earns high levels of protection, while lower levels of protection are accorded to information deemed public or non-sensitive. Challenging this dichotomy, the theory of contextual integrity associates privacy with complex typologies of information, each connected with respective social contexts. Moreover, it contends that information type is merely one among several variables that shape people’s privacy expectations and underpin privacy’s normative foundations. Other contextual variables include key actors - information subjects, senders, and recipients - as well as the principles under which information is transmitted, such as whether with subjects’ consent, as bought and sold, as required by law, and so forth. Prior work revealed the systematic impact of these other variables on privacy assessments, thereby debunking the defining effects of so-called private information. In this paper, we shine a light on the opposite effect, challenging conventional assumptions about public information. The paper reports on a series of studies, which probe attitudes and expectations regarding information that has been deemed public. Public records established through the historical practice of federal, state, and local agencies, as a case in point, are afforded little privacy protection, or possibly none at all. Motivated by progressive digitization and creation of online portals through which these records have been made publicly accessible our work underscores the need for more concentrated and nuanced privacy assessments, even more urgent in the face of vigorous open data initiatives, which call on federal, state, and local agencies to provide access to government records in both human and machine readable forms. Within a stream of research suggesting possible guard rails for open data initiatives, our work, guided by the theory of contextual integrity, provides insight into the factors systematically shaping individuals’ expectations and normative judgments concerning appropriate uses of and terms of access to information. Using a factorial vignette survey, we asked respondents to rate the appropriateness of a series of scenarios in which contextual elements were systematically varied; these elements included the data recipient (e.g. bank, employer, friend,.), the data subject, and the source, or sender, of the information (e.g. individual, government, data broker). Because the object of this study was to highlight the complexity of people’s privacy expectations regarding so-called public information, information types were drawn from data fields frequently held in public government records (e.g. voter registration, marital status, criminal standing, and real property ownership). Our findings are noteworthy on both theoretical and practical grounds. In the first place, they reinforce key assertions of contextual integrity about the simultaneous relevance to privacy of other factors beyond information types. In the second place, they reveal discordance between truisms that have frequently shaped public policy relevant to privacy. For example, • Ease of accessibility does not drive judgments of appropriateness. Thus, even when respondents deemed information easy to access (marital status) they nevertheless judged it inappropriate (“Not OK”) to access this information under certain circumstances.• Even when it is possible to find certain information in public records, respondents cared about the immediate source of that information in judging whether given data flows were appropriate. In particular, no matter that information in question was known to be available in public records, respondents deemed inappropriate all circumstances in which data brokers were the immediate source of information. • Younger respondents (under 35 years old) were more critical of using data brokers and online government records as compared with the null condition of asking data subjects directly, debunking conventional wisdom that “digital natives” are uninterested in privacy. One immediate application to public policy is in the sphere of access to records that include information about identifiable or reachable individuals. This study has shown that individuals have quite strong normative expectations concerning appropriate access and use of information in public records that do not comport with the maxim, “anything goes.” Furthermore, these expectations are far from idiosyncratic and arbitrary. Our work calls for approaches to providing access that are more judicious than a simple on/off spigot. Complex information ontologies, credentials of key actors (i.e. sender and recipients in relation to data subject), and terms of access – even lightweight ones – such as, identity or role authentication, varying privilege levels, or a commitment to limited purposes may all be used to adjust public access to align better with legitimate privacy expectations. Such expectations should be systematically considered when crafting policies around public records and open data initiatives.

An AREA-Oriented Heuristic for Scheduling DAGs on Volatile Computing Platforms

Many modern computing platforms—notably clouds and desktop grids—exhibit dynamic heterogeneity: the availability and computing power of their constituent resources can change unexpectedly and dynamically, even in the midst of a computation. We introduce a new quality metric, AREA, for schedules that execute computations having interdependent constituent chores (jobs, tasks, etc.) on such platforms. AREA measures the average number of chores that a schedule renders eligible for execution at each step of a computation. Even though the definition of AREA does not mention any properties of host platforms (such as volatility), intuition suggests that rendering chores eligible at a faster rate will have a benign impact on the performance of volatile platforms. We report on simulation experiments that support this intuition. Earlier work has derived the basic properties of the AREA metric and has shown how to efficiently craft AREA-maximizing ( A-M ) schedules for several classes of significant computations. Even though A-M schedules always exist for every computation, it is not always known how to derive such schedules efficiently. In response, the current study develops an efficient algorithm that produces AREA-Oriented ( A-O ) schedules, which aim to efficiently approximate the AREAs of A-M schedules on arbitrary computations. The simulation experiments reported on here suggest that, in common with A-M schedules, A-O schedules complete computations on volatile heterogeneous platforms faster than a variety of heuristics that range from lightweight ones to computationally intensive ones—albeit not to the same degree as A-M schedules do. Our experiments suggest that schedules having larger AREAs have smaller completion times—but no proof of that yet exists.

Comparison of behaviour, performance and mortality in restricted and ad libitum-fed growing rabbits

The objective of this study was to determine whether rabbits fed in a restricted regimen (75%) showed increased competition for feeding, drinking and use of specific areas of the cages as compared with those provided feed ad libitum. This evaluation was carried out by measuring their space utilisation in the cage, the incidence of agonistic behaviour and rates of mortality. In total, 504 rabbits between 31 and 66 days of age were used in this study. A total of 200 heavy-weight rabbits and 56 light-weight rabbits were randomly housed in 32 cages, each cage containing eight rabbits: 25 cages housing heavy rabbits and seven cages housing the light-weight ones. They were all fed ad libitum (AD). In addition, a total of 208 heavy-weight rabbits and 40 light-weight rabbits were randomly housed in 31 cages, each of them containing eight rabbits: 26 cages housing heavy weight rabbits and five cages housing light-weight ones. They were all fed a restricted diet (R) regimen. The restriction was calculated to be 75% of the feed consumed by the AD group. The total space available in the cage was 3252 cm2, with a stocking density of 24.6 animals/m2. Animals between 32 and 60 days of age from 20 different cages were observed nine times per week (morning or afternoon) by means of scan and focal sampling by one observer. During each period, cages were assessed for 5 min, registering every minute the position of all the animals in relation to Area A (feeder), Area B (central part) or Area C (back and drinker area). The incidence of agonistic behaviour such as displacement, biting and jumping on each other was also assessed. Performance variables such as daily gain and feed conversion ratio, in addition to general health status and mortality rates, were recorded for all rabbits. When the rabbits were under restricted feeding, the competition for feed and drink increased with clear signs of agonistic behaviour such as biting, displacement and animals jumping on top of each other. Although this competition was maintained during the entire growing period, the BW homogeneity between animals in the same cage was similar in both cases, suggesting that all animals could consume similar quantities of feed. The possible advantages of a restricted diet, such as better feed conversion ratio, were observed in this study only in the last few weeks of the growing period.