Miracle-dz/UniFAR-FTUs huggingface dataset:
An efficient approach to mobile robot motion planning in dynamically unknown environments

This paper presents an efficient reactive approach to mobile robot motion planning in dynamically unknown environments featuring multi-shaped obstacles moving with varying velocities both in direction and in magnitude. In order to endow the mobile robot with real-time response capability, the entire motion planning duration is divided into tiny time slices during each of which a control input is determined for the mobile robot. We present a concept of a conservative collision-free state and mathematically define a collision-free state area as a feasible solution space which guarantees the safety in such a way that, as long as the center of the mobile robot is located in the solution space, a collision with any obstacles will never occur until the current time slice expires. Then, a reasonable oriented point is rapidly selected from the feasible solution space through a greedy principle based upon an equal angle-interval sampling method. In order to improve the escape capability of the mobile robot operating in a crowded environment, we present an urgency strategy by establishing a virtual repulsive force field around the mobile robot and determining the escape orientation via a potential energy function defined in the force field. Simulation results show that this reactive approach is very effective and well-suited for mobile robot motion planning in dynamically unknown environments.
Speed Control of BLDC Motor with Common Current

This paper describes the current control mechanism for Brushless DC motors based on a mean DC signal (i.e., generation of quasi-square wave currents using only one current controller for three phases). The control mechanism also allows regenerative braking which is very important in many electrical applications. This method successfully remove excessive current and consequent back EMF present at the end of the commutation period for brushless DC motors, results in improvement in efficiency and lower acoustic noise. Also current modulation can be done using triangular carrier modulation which is an additional advantage. The mechanism is developed and implement on the MATLAB/Simulink.
The Effect of Carbon Credits on Savanna Land Management and Priorities for Biodiversity Conservation

Carbon finance offers the potential to change land management and conservation planning priorities. We develop a novel approach to planning for improved land management to conserve biodiversity while utilizing potential revenue from carbon biosequestration. We apply our approach in northern Australia's tropical savanna, a region of global significance for biodiversity and carbon storage, both of which are threatened by current fire and grazing regimes. Our approach aims to identify priority locations for protecting species and vegetation communities by retaining existing vegetation and managing fire and grazing regimes at a minimum cost. We explore the impact of accounting for potential carbon revenue (using a carbon price of US$14 per tonne of carbon dioxide equivalent) on priority areas for conservation and the impact of explicitly protecting carbon stocks in addition to biodiversity. Our results show that improved management can potentially raise approximately US$5 per hectare per year in carbon revenue and prevent the release of 1–2 billion tonnes of carbon dioxide equivalent over approximately 90 years. This revenue could be used to reduce the costs of improved land management by three quarters or double the number of biodiversity targets achieved and meet carbon storage targets for the same cost. These results are based on generalised cost and carbon data; more comprehensive applications will rely on fine scale, site-specific data and a supportive policy environment. Our research illustrates that the duel objective of conserving biodiversity and reducing the release of greenhouse gases offers important opportunities for cost-effective land management investments.
A Generator for Time-Predictable Code

Time-predictability is an essential property of software components of safety-critical hard real-time systems. Single-path code generation produces code that forces every execution to follow the same trace of instructions, thus making the execution time of code independent of its input data. This supports the time predictability of components and simplifies their worst-case execution-time analysis. In this paper we present the implementation of a single-path code generator in a compiler for a time-predictable processor. The evaluation on a real-world application shows that single-path code generation is a practicable strategy for the construction of time-predictable software components.
Geo-spatial autocorrelation as a metric for the detection of Fast-Flux botnet domains

Botnets consist of thousands of hosts infected with malware. Botnet owners communicate with these hosts using Command and Control (C2) servers. These C2 servers are usually infected hosts which the botnet owners do not have physical access to. For this reason botnets can be shut down by taking over or blocking the C2 servers. Botnet owners have employed numerous shutdown avoidance techniques. One of these techniques, DNS Fast-Flux, relies on rapidly changing address records. The addresses returned by the Fast-Flux DNS servers consist of geographically widely distributed hosts. The distributed nature of Fast-Flux botnets differs from legitimate domains, which tend to have geographically clustered server locations. This paper examines the use of spatial autocorrelation techniques based on the geographic distribution of domain servers to detect Fast-Flux domains. Moran's I and Geary's C are used to produce classifiers using multiple geographic co-ordinate systems to produce efficient and accurate results. It is shown how Fast-Flux domains can be detected reliably while only a small percentage of false positives are produced.
Bagging to find better expansion words

The supervised learning has been applied into the query expansion techniques, which trains a model to predict the “goodness” or “utility” of the expanded term to the retrieval system. There are many features to measure the relatedness between the expanded word and the query, which can be incorporated in the supervised learning to select the expanded terms. The training data set is generated automatically by a tricky method. However, this method can be affected by many aspects. A severe problem is that the distribution of the features is query-dependent, which has not been discussed in previous work. With a different distribution on the features, it is questionable to merge these training instances together and use the whole data set to train one single model. In this paper, we first investigate the statistical distribution of the auto-generated training data and show the problems in the training data set. Based on our analysis, we proposed to use the bagging method to ensemble several regression models in order to get a better supervised model to make prediction on the expanded terms. We conducted the experiments on the TREC benchmark test collections. Our analysis on the training data reveals some interesting phenomena about the query expansion techniques. The experiment results also show that the bagging approach can achieve the state-of-art retrieval performance on the standard TREC data set.
On the rigidity of the cytoskeleton: are MAPs crosslinkers or spacers of microtubules?

Microtubules are fibers of the cytoskeleton involved in mitosis, intracellular transport, motility and other functions. They contain microtubule-associated proteins (MAPs) bound to their surface which stabilize microtubules and promote their assembly. There has been a debate on additional functions of MAPs, e.g. whether MAPs crosslink microtubules and thus increase their rigidity, or whether they act as spacers between them. We have studied the packing of microtubules in the presence of MAPs by solution X-ray scattering using synchrotron radiation. Microtubules free in solution produce a scattering pattern typical of an isolated hollow cylinder, whereas tightly packed microtubules generate a pattern dominated by interparticle interference. The interference patterns are interpreted in terms of the Hosemann paracrystal concept, adapted for arrays of parallel fibers with hexagonal arrangement in the plane perpendicular to the fiber axes (Briki et al., 1998). Microtubules without MAPs can rapidly and efficiently be compressed by centrifugation, as judged by the transition from a "free microtubule" to a "packed microtubule" X-ray scattering pattern. MAPs make the microtubule array highly resistant to packing, even at high centrifugal forces. This emphasizes the role of MAPs as spacers of microtubules rather than crosslinkers. A possible function is to keep the microtubule tracks free for the approach of motor proteins carrying vesicle or organelle cargoes along microtubules.
THE CRAB NEBULA'S COMPOSITION AND PRECURSOR STAR MASS

We present new photoionization calculations for investigating gaseous regions that represent potentially expected stages of nuclear processing in the Crab Nebula supernova remnant. From comparison of the theoretical models with recent, extensive emission-line measurements, most of the emitting gas appears to be nitrogen-poor and carbon-rich. These results suggest that the precursor star had an initial mass ≳ 9.5 M☉.
Filtering by repeated integration

Many applications of digital filtering require a space variant filter - one whose shape or size varies with position. The usual algorithm for such filters, direct convolution, is very costly for wide kernels. Image prefiltering provides an efficient alternative. We explore one prefiltering technique, repeated integration, which is a generalization of Crow's summed area table.We find that convolution of a signal with any piecewise polynomial kernel of degree n--1 can be computed by integrating the signal n times and point sampling it several times for each output sample. The use of second or higher order integration permits relatively high quality filtering. The advantage over direct convolution is that the cost of repeated integration filtering does not increase with filter width. Generalization to two-dimensional image filtering is straightforward. Implementations of the simple technique are presented in both preprocessing and stream processing styles.
The Conditional Nature of Embeddedness: A Study of Borrowing by Large U.S. Firms, 1973–1994

Economic and organizational sociologists have increasingly demonstrated that the actions of individuals and firms are affected by the social networks within which they are embedded. In recent years scholars have begun to recognize that the effects of these social networks may vary across populations or types of relations. This article examines the extent to which the effects of interfirm networks on the behavior of firms are historically contingent. Focusing on the level of debt financing among approximately 140 large U.S. corporations over a 22-year period, the authors show that the extent to which the firms' use of debt was influenced by those with which they were tied through director interlocks declined over time. The authors argue that this decline in the network effect reflected a shift in the institutional environment within which the firms operated, and that it was driven by three processes: the professionalization of the finance function within the firm, the internalization of financial decision-making, and the increased volatility of the environment. They conclude that corporate financing is socially embedded, but this embeddedness is historically contingent.
Utah Teachers' Perceptions of Student Social Skills and Behaviors: A Developmental Perspective

Utah Teachers’ Perceptions of Student Social Skills and Behaviors: A Developmental Perspective Karrah Beth Sampson Department of Counseling Psychology and Special Education, BYU Educational Specialist Students’ appropriate social skills and behaviors are essential for classroom success at any level but are of special importance at an elementary school level when the foundations of these skill sets are developing (Lane, Givner, & Pierson, 2004). An initial study investigated which social skills Utah elementary school teachers identified as being most important, and which behaviors are most problematic during the elementary school years. Elementary school teachers (Kindergarten through sixth grade) were randomly selected from Utah’s school districts. In total, 295 of 1,144 teachers (26% return rate) participated (Weed, 2015). As a follow-up, this current study utilized data from the initial study and analyzed teachers’ perceptions by grade level, determining if there were discernible differences between the grades. A statistically significant difference was found in the social skill of following directions between third and fifth grade with the mean for third grade being higher. This suggests that third grade teachers viewed following directions as a more important social skill for students to display than fifth grade teachers did. Between first and fourth grade there were significant differences in both the areas of anxiousness and trouble making friends, again with first grade results showing higher means in both areas. This suggests that based on their teaching experiences, first grade teachers would find these behaviors more problematic in their classroom than fourth grade teachers. In all areas of statistical significance, the mean of the younger grade was higher than that of the lower grade suggesting that these behaviors are considered more problematic to teachers of younger grades. These differences are important to consider when helping schools address children’s social skills, taking into account potential developmental differences that emerge across ages. Additionally this age-specific information will assist school-based mental health practitioners to understand teachers’ perceptions of which specific social skills are considered most important at a particular point in time so that these skills can be targeted as needed.
Nieuwsgierigheid in kaart gebracht: Validatiestudie van de Epistemic Curiosity Scale in de Nederlandse onderwijscontext

De doelstelling van het onderzoek is de validering van een vertaald meetinstrument om nieuwsgierigheid van leerlingen en studenten in Nederland in kaart te kunnen brengen. De centrale onderzoeksvraag luidt: In hoeverre geeft de vertaalde, Nederlandstalige versie van de Epistemic Curiosity Scale (Litman, 2008) een betrouwbaar en valide beeld van de mate van nieuwsgierigheid van leerlingen in het voortgezet onderwijs en studenten in het mbo en hbo? De vragenlijst onderscheidt twee componenten van nieuwsgierigheid: gevoelens van deprivatie (D-type nieuwsgierigheid) en gevoelens van interesse (I-type nieuwsgierigheid). De vragenlijst is afgenomen bij 131 leerlingen in het voortgezet onderwijs, 188 mbo-studenten en 282 hbo-studenten. Uit de resultaten komt eenduidig naar voren dat het vertaalde meetinstrument de mate van nieuwsgierigheid van leerlingen en studenten goed in kaart kan brengen. De I-type en D-type schalen zijn betrouwbaar en geven een redelijk valide beeld van de mate van nieuwsgierigheid van leerlingen in het voortgezet onderwijs en studenten in het mbo en hbo. Wel bleek dat de model fit nog verder geoptimaliseerd kan worden door de formulering van enkele items te verbeteren.
“Nomophobia”: Impact of Cell Phone Use Interfering with Symptoms and Emotions of Individuals with Panic Disorder Compared with a Control Group

Panic disorder refers to the frequent and recurring acute attacks of anxiety. Objective: This study describes the routine use of mobiles phones (MPs) and investigates the appearance of possible emotional alterations or symptoms related to their use in patients with panic disorder (PD). Background: We compared patients with PD and agoraphobia being treated at the Panic and Respiration Laboratory of The Institute of Psychiatry, Federal University of Rio de Janeiro, Brazil, to a control group of healthy volunteers. Methods: An MP-use questionnaire was administered to a consecutive sample of 50 patients and 70 controls. Results: People with PD showed significant increases in anxiety, tachycardia, respiratory alterations, trembling, perspiration, panic, fear and depression related to the lack of an MP compared to the control group. Conclusions: Both groups exhibited dependence on and were comforted by having an MP; however, people with PD and agoraphobia showed significantly more emotional alterations as well as intense physical and psychological symptoms when they were apart from or unable to use an MP compared to healthy volunteers.
Alberta LARGE-SCALE FRACTURE OF SEA ICE PLATES

USA Propagation of bending fracture along a floating sea ice plate, representing an elastic plate on elastic foundation, is analyzed in the sense of linear elastic fracture mechanics (LEFM), assuming the entire plate thickness to be fractured all the way to the fracture tip. The analysis focuses on the size effect. Two specific problems are solved in an idealized form: steady state propagation of thermal bending fracture and vertical penetration of an object through the plate. In both problems it is found that the nominal strength (equivalent to the ~ritical temperature difference in the first problem) decreases as (thickness)-3/8. In the thermal problem, the (73/8)-power law is exact (under the hypotheses of the analysis), while in the penetration problem it is only approximate, approached asymptotically for large sizes. This (-3/8)-power law differs from that known for two-dimensional or axisymmetric LEFM, in which the nominal strength scales as (size)-1/2; the difference is caused by the presence of a characteristic length for bending disturbance decay along the plate. An in-plane compressive force makes the size effect stronger than (thickness)-3/8, and an in-plane tensile force makes it weaker. Creep and propagation rate effects are approximately taken into account in the thermal problem, and so is the effect of in-plane forces on bending. A numerical example shows that the temperature changes occurring in the Arctic suffice, according to the present theory, to produce bending fractures. Such fractures might serve to initiate the formation of leads of open water, pressure ridges and rafting.
Scalable Distributed Address Assignment for Low Rate Wireless Personal Area Network

IEEE 802.15. 4 protocol provides a low data rate and low energy consumption solution for wireless sensor networks which are the basis of the Internet of Things. However, the variable topology of wireless networks requires high flexibility and robustness to be achieved by network configuration mechanisms. In this paper, a Scalable Distributed Address Assignment Mechanism (SDAAM) is designed, which adopts adaptive approach to handle the variability present in the topology of wireless networks. In the proposed approach, every newly arrived node can be correctly configured regardless of the current network topology so that it can communicate with other nodes within the same network. Another important advantage of SDAAM is its handling of unexpected events which may arise due to migration or departure of nodes in the network. Detailed description about SDAAM is presented and its effectiveness and high flexibility is demonstrated based on the simulation program.
CD8+ T Cell Fate and Function Influenced by Antigen-Specific Virus-Like Nanoparticles Co-Expressing Membrane Tethered IL-2

A variety of adjuvants fostering humoral immunity are known as of today. However, there is a lack of adjuvants or adjuvant strategies, which directly target T cellular effector functions and memory. We here determined whether systemically toxic cytokines such as IL-2 can be restricted to the site of antigen presentation and used as ‘natural adjuvants’. Therefore, we devised antigen-presenting virus-like nanoparticles (VNP) co-expressing IL-2 attached to different membrane-anchors and assessed their potency to modulate CD8+ T cell responses in vitro and in vivo. Efficient targeting of IL-2 to lipid rafts and ultimately VNP was achieved by fusing IL-2 at its C-terminus to a minimal glycosylphosphatidylinositol (GPI)-anchor acceptor sequence. To identify optimal membrane-anchor dimensions we inserted one (1Ig), two (2Ig) or four (4Ig) immunoglobulin(Ig)-like domains of CD16b between IL-2 and the minimal GPI-anchor acceptor sequence of CD16b (GPI). We found that the 2IgGPI version was superior to all other evaluated IL-2 variants (IL-2v) in terms of its i) degree of targeting to lipid rafts and to the VNP surface, ii) biological activity, iii) co-stimulation of cognate T cells in the absence of bystander activation and iv) potency to induce differentiation and acquisition of CD8+ T cell effector functions in vitro and in vivo. In contrast, the GPI version rather favored memory precursor cell formation. These results exemplify novel beneficial features of membrane-bound IL-2, which in addition to its mere T cell stimulatory capacity include the induction of differential effector and memory functions in CD8+ T lymphocytes.
Shooting Methods for Locating Grazing Phenomena in Hybrid Systems

Hybrid systems are typified by strong coupling between continuous dynamics and discrete events. For such piecewise smooth systems, event triggering generally has a significant influence over subsequent system behavior. Therefore, it is important to identify situations where a small change in parameter values alters the event triggering pattern. The bounding case, which separates regions of (generally) quite different dynamic behaviors, is referred to as grazing. At a grazing point, the system trajectory makes tangential contact with an event triggering hypersurface. The paper formulates conditions governing grazing points. Both transient and periodic behaviors are considered. The resulting boundary value problems are solved using shooting methods that are applicable for general nonlinear hybrid (piecewise smooth) dynamical systems. The grazing point formulation underlies the development of a continuation process for exploring parametric dependence. It also provides the basis for an optimization technique that finds the smallest parameter change necessary to induce grazing. Examples are drawn from power electronics, power systems and robotics, all of which involve intrinsic interactions between continuous dynamics and discrete events.
Exploring the social function of congregations: A community development approach to develop ‘hub-and-spill’ early childhood development centres

This article reflects on the findings of a research study that investigated a community development project by CARITAS, a welfare organisation of the Dutch Reformed Church (DRC). The said organisation, together with local DRC congregations, and in a quest to address societal issues such as poverty and child neglect in the Northern Cape, developed early childhood development (ECD) centres in rural towns. The aim was to provide young children with quality care and to provide congregations with a platform to become active participants in community development projects. The study was conducted 5 years after the start of the project to explore the nature and value thereof. The outcomes of the study provide valuable insights regarding how such centres served as a tool to work towards ECD and a sense of community in these towns, while also addressing socio-economic issues. This article is aimed at presenting the findings as an example to be explored in other contexts.