Miracle-dz/UniFAR-FTUs huggingface dataset:
2 F eb 2 00 5 On the Fixed Homogeneous Circle Problem

We give some results about the dynamics of a particle moving in Euclidean three-space under the influence of the gravitational force induced by a fixed homogeneous circle. Our main results concern (1) singularities and (2) the dynamics in the plane that contains the circle. The study presented here is purely analytic. In this paper we present a first study about the movement of a particle in Euclidean three-space IR 3 on which the only acting force is the gravitational force induced by a fixed homogeneous circle. Even though this problem seems quite natural, we could not find in the literature any reference concerning the dynamics of it. All we could find were a few different ways of expressing the potential function. Essentially all these expressions had already appeared in Poincare's Théorie du Potentiel Newtonien [3], published first in 1899. Probably the most well-known expressions are the one expressed in terms of elliptic integrals of the first kind and the one using the arithmetic-geometric mean given by Gauss. We believe this is the first study presented about the dynamics of this problem. Before we present our first result we need some notation and a couple of definitions. We want to study the movement in IR 3 of a particle P under the influence of the gravitational force induced by a fixed homogeneous circle C. Denote by r = (x, y, z) ∈ IR 3 − C the position of the particle P. Also ˙ r = (˙ x, ˙ y, ˙ z) denotes its velocity. According to Newton's Law the movement of P obeys the following second order differential equation: . where V denotes the potential energy induced by C. The expression of V is given by V (r) = − C λ du ||r−u|| , where λ is the constant mass density of the circle C. We say that a solution r(t), defined in the maximal interval (a, b), has a singularity at b (or at a), if b < +∞ (if a > −∞). We can now ask: if lim t→b − dist(r(t), C) = 0, b < +∞, does r(t) approach a well defined point in C ? A priori, r(t) could approach the circle without getting closer to any specific point in the circle. A singularity at c is called a collision singularity if there exists r * ∈ C such that r(t) → r * , …
Liquid interface: a malleable, transient, direct-touch interface

We present a new methodology based on ferromagnetic fluids in which the user can have direct interaction (input/output) through a tangible and malleable interface. Liquid Interfaces uses the physical qualities of ferromagnetic fluids in combination with capacitive, multi-touch technology, to produce a 3D, multi-touch interface where actuation, representation, and self-configuration occur through the malleable liquid, ferromagnetic fluid. This, combined with the ability to produce sound, enables users to create musical sculptures that can be morphed in real time by interacting directly with the ferromagnetic fluid.
Influences on Career Choice Among Psychology Undergraduate Students: Role of Social Agents

The study explored factors that mediate the choice of psychology as a major subject by undergraduate students. Participants were a convenience sample of 368 students from two higher education institutions in Southern Africa (males =186, females =182, mean age = 22.35 years, SD=2.84 years). Data were collected using a survey that investigated social agents that are considered important in students' career choices. The data were analysed to explore differences by family and peer influences. The findings suggest that the students in the sample regarded social influences important in their choice of psychology as a major subject.
A practical study of textile TM01 mode circular patch antenna for wireless body area network applications

A textile circular patch antenna for wireless body area network is proposed. The proposed textile antenna has the radiation directed toward the surface of the human body in the 5.8 GHz industrial, scientific, medical band. In order to consider the practical situations, the numerical experiments were carried out on different body locations such as arm and chest of human.
An improved method for measuring concept semantic similarity combining multiple metrics

Ontology-based semantic similarity measures the similarity between the concepts, which is widely used in information retrieval and semantic web service fields. Existing studies of semantic similarity matching algorithm are mainly focused on computing the semantic distance between concepts, the notion of information content or the overlap of concept attributes. But most of these algorithms calculate semantic similarity in their own way without taking other factors into account. This paper proposes a novel algorithm which combines three factors mentioned above. To avoid unreasonable artificial weight setting, the principal component analysis is used to weigh each factor's contribution to the semantic similarity. The experimental evaluations using WordNet proves that the algorithm presented in this paper improves the accuracy of semantic similarity and the results are more close to human judgment.
Leaf Anatomy and Photochemical Behaviour of Solanum lycopersicum L. Plants from Seeds Irradiated with Low-LET Ionising Radiation

Plants can be exposed to ionising radiation not only in Space but also on Earth, due to specific technological applications or after nuclear disasters. The response of plants to ionising radiation depends on radiation quality/quantity and/or plant characteristics. In this paper, we analyse some growth traits, leaf anatomy, and ecophysiological features of plants of Solanum lycopersicum L. “Microtom” grown from seeds irradiated with increasing doses of X-rays (0.3, 10, 20, 50, and 100 Gy). Both juvenile and compound leaves from plants developed from irradiated and control seeds were analysed through light and epifluorescence microscopy. Digital image analysis allowed quantifying anatomical parameters to detect the occurrence of signs of structural damage. Fluorescence parameters and total photosynthetic pigment content were analysed to evaluate the functioning of the photosynthetic machinery. Radiation did not affect percentage and rate of seed germination. Plants from irradiated seeds accomplished the crop cycle and showed a more compact habitus. Dose-depended tendencies of variations occurred in phenolic content, while other leaf anatomical parameters did not show distinct trends after irradiation. The sporadic perturbations of leaf structure, observed during the vegetative phase, after high levels of radiation were not so severe as to induce any significant alterations in photosynthetic efficiency.
Design of a high-voltage differential amplifier based on stacked low-voltage standard CMOS with different input stages

This paper presents the design of a high-voltage differential amplifier using six different pre-input stage circuits to reduce high-voltage input levels to low-voltage signals. The proposed circuits are designed using 65 nm CMOS process technology with a nominal voltage of 2.5 V and a supply voltage of 5 V. The designs are based on stacked low-voltage standard CMOS transistors. The different pre-input stage circuits are compared to each other in terms of their circuit description, drawbacks, advantages and simulation results. The principle of the five designed pre-input stage circuits can be applied to higher voltage range input signals as well.
Microbiological Sealing Analysis of a Tapered Connection and External Hexagon System

Considering the variety of implant connection systems available in the market and the contrasting literature regarding tapered connection systems in terms of bacterial leakage, the aim of this in vitro study was to compare the effectiveness of the bacterial seal at the implant/abutment interface between an external hexagon and a tapered connection system. Twelve sets of indexed tapered connection components and twelve sets of external hexagon connection components were used for microbiological analysis. In addition, for each model, an implant with its respective prosthetic abutment was used as a negative control and another as a positive control of microbial contamination. Failure of the abutment/implant interface seal was observed via turbidity or presence of deposits in the culture. Descriptive analysis of the data and relative frequency (percentage) as well as Fisher's exact test were used at a significance level of 5%. Two of ten (20%) external hexagon specimens showed contamination against 0/10 (0%) tapered connection implants. In conclusion, both implant/abutment connections were able to prevent bacterial leakage in vitro.
Novel Microdilution Method to Assess Double and Triple Antibiotic Combination Therapy In Vitro

An in vitro microdilution method was developed to assess double and triple combinations of antibiotics. Five antibiotics including ciprofloxacin, amikacin, ceftazidime, piperacillin, and imipenem were tested against 10 clinical isolates of Pseudomonas aeruginosa. Each isolate was tested against ten double and nine triple combinations of the antibiotics. A 96-well plate was used to test three antibiotics, each one alone and in double and triple combinations against each isolate. The minimum bacteriostatic and bactericidal concentrations in combination were determined with respect to the most potent antibiotic. An Interaction Code (IC) was generated for each combination, where a numerical value was designated based on the 2-fold increase or decrease in the MICs with respect to the most potent antibiotic. The results of the combinations were verified by time-kill assay at constant concentrations of the antibiotics and in a chemostat. Only 13% of the double combinations were synergistic, whereas 5% showed antagonism. Forty-three percent of the triple combinations were synergistic with no antagonism observed, and 100% synergism was observed in combination of ciprofloxacin, amikacin, and ceftazidime. The presented protocol is simple and fast and can help the clinicians in the early selection of the effective antibiotic therapy for treatment of severe infections.
Redundancy, resilience, and host specificity of the ruminal microbiota: implications for engineering improved ruminal fermentations

The ruminal microbial community is remarkably diverse, containing 100s of different bacterial and archaeal species, plus many species of fungi and protozoa. Molecular studies have identified a “core microbiome” dominated by phyla Firmicutes and Bacteroidetes, but also containing many other taxa. The rumen provides an ideal laboratory for studies on microbial ecology and the demonstration of ecological principles. In particular, the microbial community demonstrates both redundancy (overlap of function among multiple species) and resilience (resistance to, and capacity to recover from, perturbation). These twin properties provide remarkable stability that maintains digestive function for the host across a range of feeding and management conditions, but they also provide a challenge to engineering the rumen for improved function (e.g., improved fiber utilization or decreased methane production). Direct ruminal dosing or feeding of probiotic strains often fails to establish the added strains, due to intensive competition and amensalism from the indigenous residents that are well-adapted to the historical conditions within each rumen. Known exceptions include introduced strains that can fill otherwise unoccupied niches, as in the case of specialist bacteria that degrade phytotoxins such as mimosine or fluoroacetate. An additional complicating factor in manipulating the ruminal fermentation is the individuality or host specificity of the microbiota, in which individual animals contain a particular community whose species composition is capable of reconstituting itself, even following a near-total exchange of ruminal contents from another herd mate maintained on the same diet. Elucidation of the interactions between the microbial community and the individual host that establish and maintain this specificity may provide insights into why individual hosts vary in production metrics (e.g., feed efficiency or milk fat synthesis), and how to improve herd performance.
Consolidating Birth-Death and Death-Birth Processes in Structured Populations

Network models extend evolutionary game theory to settings with spatial or social structure and have provided key insights on the mechanisms underlying the evolution of cooperation. However, network models have also proven sensitive to seemingly small details of the model architecture. Here we investigate two popular biologically motivated models of evolution in finite populations: Death-Birth (DB) and Birth-Death (BD) processes. In both cases reproduction is proportional to fitness and death is random; the only difference is the order of the two events at each time step. Although superficially similar, under DB cooperation may be favoured in structured populations, while under BD it never is. This is especially troubling as natural populations do not follow a strict one birth then one death regimen (or vice versa); such constraints are introduced to make models more tractable. Whether structure can promote the evolution of cooperation should not hinge on a simplifying assumption. Here, we propose a mixed rule where in each time step DB is used with probability and BD is used with probability . We derive the conditions for selection favouring cooperation under the mixed rule for all social dilemmas. We find that the only qualitatively different outcome occurs when using just BD (). This case admits a natural interpretation in terms of kin competition counterbalancing the effect of kin selection. Finally we show that, for any mixed BD-DB update and under weak selection, cooperation is never inhibited by population structure for any social dilemma, including the Snowdrift Game.
OST-Tree: An Access Method for Obfuscating Spatio-Temporal Data in Location Based Services

Since the development of location-based services, privacy-preserving has gained special attention and many algorithms aiming at protecting user's privacy have been created such as obfuscation or k-anonymity. However, all of these researches separate the algorithms from the database level. Thus, the querying process has two phases, querying the database to retrieve the accurate positions of users and then modifying them to decrease the quality of location information. This two-phase process is time-consuming due to the number of disk accesses required to retrieve the user's exact position. We address this problem by proposing OST-tree, a structure that embeds the user's privacy policy in its node and obfuscates the spatio-temporal data. Experiments show that OST-tree provides an improvement over the algorithm separated from the database level for both querying costs and user's privacy protection.
Relay assignment in multiuser cooperative radio networks with QoS guarantee

Adaptive cooperation with conflict-free relay assignment in a network setting is a challenging problem. The problem becomes even more difficult when users have quality-of-service (QoS) requirements but the available spectrum resource is limited, where admission control may be required. In this paper, we jointly study relay assignment and admission control in cooperative radio networks (CRNs). A one-stage optimization problem is formulated to integrate our multiple objectives. Since the problem in question is prohibitively difficult, we resort to an appropriate decomposition approach after a careful analysis on the structure of the formulated problem. A simple distributed algorithm is also proposed to overcome the inherent drawbacks of the centralized scheme. Numerical results demonstrate the benefits attained by jointly considering relay assignment and admission control, as well as the effectiveness of our proposed algorithms.
HiPEC: high performance external virtual memory caching

Traditional operating systems use a fixed LRU-like page replacement policy and centralized frame pool that cannot properly serve all types of memory access patterns of various applications As a result many memory-intensive applications such as databases multimedia applications and scientific simulators induce excessive page faults and page replacement when running on top of existing operating systems. This paper presents a High Performance External virtual memory Caching mechanism (HiPEC) to provide applications with their own specific page replacement management. The user specific policy programmed in the HiPEC command set is stored in user address space. When a page fault occurs the kernel fetches and interprets the corresponding policy commands to perform the user specific page replacement management. Experimental results show that HiPEC induces little overhead and can significantly improve performance for memory-intensive applications.
Knowledge in question : from Taylorism to Knowledge Management

The management sciences have accustomed us to seeing a succession of concepts and tools which are presented by some as revolutionary. For some years, Knowledge Management (KM) has been at the head of the class. Uncounted publications work at defining the concept and detailing the best ways to put it into practice. At a moment when people are making speeches (especially political speeches) which substitute the concept of an “information society” for that of a “knowledge-based society”, this attention to knowledge by managers is of particular interest. Today, knowledge is presented as a new object of management for theoreticians and practitioners, in the same manner as production by example - but the novelty is quite relative. In fact TAYLOR had already made the management of knowledge an important factor in the development of industrial societies. Analyzing the similarities between TAYLOR’s work and work on KM is very instructive. If we examine the former, we see more clearly the vision of the world which TAYLOR had in mind. We will show that despite the separation in time and the great disparity of the contexts in which each appeared, the work of TAYLOR and work done on KM both depend on a certain vision of the world. We will also show that the two perspectives share a common concept of organization as reified, organization without conflict. And the two also share common principles concerning the execution of their projects. Both depend on transparency, and through a recourse to codification, they instrumentalize their projects. Finally, both set managerial goals which involve the reduction of uncertainties, which in both cases leads to consequences as regards the power relationships within a given organization. Our examination of the original Taylorist writings and the current KM literature thus seeks a better grasp of what is at stake, and of the consequences which are likely to follow any inplementation of KM policies in organizations.
Succinct Representation and Leaf Languages

In this paper, we present stronger results in the theory of succinct problem representation and establish a close relationship between succinct problems and leaf languages. As a major tool, we use projection reductions from descriptive complexity theory. A succinct problem is a problem whose high complexity stems from the fact that its instances are not given straightforward, but are themselves encoded by boolean circuits. In Balcc azar et al. 92, Papa, Yann 85] there have been developed methods to quantify the complexity leap obtained this way. We prove a strictly stronger version of this result which allows iterative application and completeness results under projection reductions. A leaf language Bovet et al 92, Bovet et al 91] is the language of words accepted by a nondeterministic Turing Machine where for acceptance the word obtained by concatenating the bits at the leaves of the computation graph must t in a certain pattern. Complexity bounds on the leaf pattern allow to uniformly deene a lot of complexity classes Bovet et al 92, Bovet et al 91, Hertrampf et al 93, Jenner et al 94]. We show that the succinct version s(() of a problem is complete under projection reductions for the leaf language Leaf((). Thus, we obtain an easy uniform description of generic problems complete under projection reductions for all classes de-nable as leaf languages. In the last part, we prove that s(() is not complete under monotone reductions and propose an alternative succinct representation model which allows completeness even under monotone projection reductions. This approach results in the deenition of generic problems complete under monotone projection reductions for a large number of classes. Thus we positively solve a question by Stewart, posed in Stewart 93a, Stewart 91].
Modeling malware propagation in wireless sensor networks using cellular automata

A model based on cellular automata is proposed to investigate and analyze the process of malware propagation over wireless sensor networks by way of multi-hop broadcast protocols. The model captures the inherent characteristics of wireless sensor networks, i.e. limited resource, channel contention (MAC mechanism), and also reflects the self-organization, spatio-temporal correlation of process of malware propagation. The simulation results show that MAC mechanism and density of sensor node greatly influence the malware propagation over wireless sensor network, and the malware propagation diffuses continuously from infected nodes toward outside which is spatially bounded.
Aging data in dynamic graphs: A comparative study

Dynamic graphs are used to represent changing relational data. In order to create a dynamic graph representing relationships or interactions over time, it is necessary to choose a method of adding new data and removing, or otherwise de-emphasizing, past data to decrease its influence. In particular, the question of aging edges is new to dynamic graphs and has not been thoroughly studied. In this work, we address the problem of aging vertices and edges to create a dynamic graph from a stream of temporal data. We provide two new methods, active vertex and active edge, and also evaluate two methods from the literature, sliding window and weight decay. By analyzing various properties of the dynamic graphs created by each aging method, we provide practitioners with quantitative comparisons. We find several interesting similarities and differences. The active vertex and weight decay methods reduce the variability over time of several vertex level measures compared to sliding window and active edge. This means that in practice, active vertex or weight decay may be more useful if graph stability is preferred, while sliding window or active edge may be preferred if the graph should be sensitive to changes in the underlying data stream. Each method also differently affects global measures. The most connected graph is produced by active vertex, while the most disconnected by weight decay. We observe that despite the differences, the graphs produced by each method experience similar types of changes at similar points in time.
Toward Simulation-Based Optimization in Data Stream Management Systems

Our demonstration introduces a novel system architecture which massively facilitates optimization in data stream management systems (DSMS). The basic idea is to decouple optimization from the operative system by means of a secondary optimization system, which bears the burden of determining new query plans. Within the secondary system, which typically runs on a separate machine, we utilize suitable statistical models of the original data streams to simulate them. As the simulation can run at much faster rates, we are able to examine and assess new query plans in a shorter period of time without running the risk of deteriorating the original plan; we only migrate practically approved plans into the operative system. In our demonstration, we will present our prototypical implementation of this optimization architecture. We will demonstrate the interaction between primary and secondary system as well as the key features of the whole optimization process.