Miracle-dz/UniFAR-FTUs huggingface dataset:
X-ray variability of Pleiades late-type stars as observed with the ROSAT-PSPC

We present a comprehensive analysis of X-ray variability of the late-type (dF7-dM) Pleiades stars, detected in all ROSAT-PSPC observations; X-ray variations on short (hours) and medium (months) time scales have been explored. We have grouped the stars in two samples: 89 observations of 42 distinct dF7-dK2 stars and 108 observations of 61 dK3-dM stars. The Kolmogorov-Smirnov test applied on all X-ray photon time series show that the percentage of cases of significant vari- ability is quite similar on both samples, suggesting that the presence of variability does not depend on mass for the time scales and mass range explored. The comparison between the Time X-ray Amplitude Distribution functions (XAD) of the set of dF7-dK2 and of the dK3-dM show that, on short time scales, dK3-dM stars show larger variations than dF7-dK2. A subsample of eleven dF7-dK2 and eleven dK3-dM Pleiades stars allows the study of variability on longer time scales: we found that variability on medium - long time scales is relatively more common among dF7-dK2 stars than among dK3-dM ones. For both dF7-dK2 Pleiades stars and dF7-dK2 field stars, the variability on short time scales depends on Lx while this dependence has not been observed among dK3-dM stars. It may be that the variability among dK3-dM stars is dominated by flares that have a similar luminosity distribution for stars of different Lx, while flaring distribution in dF7-dK2 stars may depend on X-ray luminosity. The lowest mass stars show significant rapid variability (flares? ) and no evidence of rotation modulation or cycles. On the contrary, dF7-dK2 Pleiades stars show both rapid variability and variations on longer time scales, likely associated with rotational modulation or cycles.
A transient I‐band excess in the optical spectrum of the accreting millisecond pulsar SAX J1808.4–3658

The optical counterpart of the transient, millisecond X-ray pulsar SAX J1808.4-3658 was observed in four colours (BVRI) for five weeks during the 2005 June-July outburst. The optical fluxes declined by � 2 magnitudes during the first 16 days and then commenced quasi-periodic secondary outbursts, with time-scales of several days, similar to those seen in 2000 and 2002. The broadband spectra derived from these measurements were generally consistent with emission from an X-ray heated accretion disc. During the first 16 days decline in intensity the spectrum became redder. We suggest that the primary outburst was initiated by a viscosity change driven instability in the inner disc and note the contrast with another accreting millisecond pulsar, XTE J0929–314, for which the spectrum becomes bluer during the decline. On the night of 2005 June 5 (HJD 2453527) the I band flux was � 0.45 magnitudes brighter than on the preceding or following nights whereas the BV & R bands showed no obvious enhancement. A Type I X-ray burst was detected by the RXTE spacecraft during this I band integration. It seems unlikely that reprocessed radiation from the burst was sufficient to explain the observed increase. We suggest that amajor part of the I band excess was due to synchrotron emission triggered by the X-ray burst. Several other significant short duration changes in V-I were detected. One occurred at about HJD 2453546 in the early phase of the first secondary outburst and may be due to a mass transfer instability or to another synchrotron emission event.
Language, culture, ontological assumptions, epistemological beliefs, and knowledge about nature and naturally occurring events: Southern African perspective

African students enter the classroom with a rich heritage of traditional beliefs that, if handled sensitively and with understanding, can play an important role in enabling learning of science. Recent developments in the understanding of how students acquire this knowledge may assist in promoting this process. This paper investigates studies situated within the worldview theory that examine the learning of science concepts within a Southern African sociocultural environment by looking at (a) the problems and solutions for students in such settings when they learn through a medium of instruction (L2 and L3) that is different from their first language (L1), (b) the nature of the worldview presuppositions held by African students on selected natural phenomena, and (c) the nature of cognitive border crossing exhibited by students from a Southern African traditional worldview to a western scientific worldview that forms the basis of a Cognitive Border Crossing Learning Model (CBCLM). Two important issues are explored in relation to the language issue: using a discourse-based model to show how accessing either spoken or written mixed discourse may facilitate learners’ comprehension of scientific discourse and allow a teacher to assist in its production, and how code switching is a useful strategy to assist border crossing in the science classroom. The CBCLM is presented as a feasible way of describing how, when, and in what contexts a student shifts from one worldview to another during the learning process.
Various schemes to detect selfishness in wireless ad-hoc networks: A survey

An ad hoc network is a suburbanized types of wireless network. The ad hoc which means “for this purpose” formed network instantly when nodes are connected in network for communication. Ad hoc network is a temporary network built for specific purpose. It does not require any pre-established infrastructure. The dynamic nature of ad hoc networks makes them more utilisable. On the other hand, selfish nodes in the network may degrade the network performance in an attempt to save their resources. The side effects of such selfish nodes are lower data accessibility, break-down in communication, and increase in communication cost for legitimate nodes and so on. In past years, various solutions for extenuating selfishness are proposed by many researchers. In this paper, we survey notable work done by various researchers to detect selfish nodes in the network. Moreover, we also mention future scope of these existing schemes which may be beneficial to researchers for further research in this direction.
Experimental Study on Connectivity for Wireless Sensor Networks

Many works have been devoted to connectivity of wireless sensor networks. This is an important feature for wireless sensor networks (WSNs) to provide the nodes with the capability of communicating with one or several sinks.To operate successfully a sensor network must also provide satisfactory connectivity so that nodes can communicate for data fusion and reporting to base stations. Connectivity affects the robustness and achievable throughput of communication in a sensor network. We provide an experimental analysis of the fundamental relationship between network connectivity and the density of nodes, as well as the relationship between network connectivity and the nodes’ transmitting ranges. Extensive experimental results prove that our method is feasible and leads to a more accurate thresholds.
Design and control of a soft, shape-changing, crawling robot

Soft materials have many important roles in animal locomotion and object manipulation. In robotic applications soft materials can store and release energy, absorb impacts, increase compliance and increase the range of possible shape profiles using minimal actuators. The shape changing ability is also a potential tool to manipulate friction forces caused by contact with the environment. These advantages are accompanied by challenges of soft material actuation and the need to exploit frictional interactions to generate locomotion. Accordingly, the design of soft robots involves exploitation of continuum properties of soft materials for manipulating frictional interactions that result in robot locomotion. The research presents design and control of a soft body robot that uses its shape change capability for locomotion. The bioinspired (caterpillar) modular robot design is a soft monolithic body which interacts with the environment at discrete contact points (caterpillar prolegs). The deformable body is actuated by muscle-like shape memory alloy coils and the discrete contact points manipulate friction in a binary manner. This novel virtual grip mechanism combines two materials with different coefficients of frictions (sticky-slippery) to control the robot-environment friction interactions. The research also introduces a novel control concept that discretizes the robot-environment-friction interaction into binary states. This facilitates formulation of a control framework that is independent of the specific actuator or soft material properties and can be applied to multi-limbed soft robots. The transitions between individual robot states are assigned a reward that allow optimized state transition control sequences to be calculated. This conceptual framework is extremely versatile and we show how it can be applied to situations in which the robot loses limb function.
Cloud Forensics: A Meta-Study of Challenges, Approaches, and Open Problems

In recent years, cloud computing has become popular as a cost-effective and efficient computing paradigm. Unfortunately, today's cloud computing architectures are not designed for security and forensics. To date, very little research has been done to develop the theory and practice of cloud forensics. Many factors complicate forensic investigations in a cloud environment. First, the storage system is no longer local. Therefore, even with a subpoena, law enforcement agents cannot confiscate the suspect's computer and get access to the suspect's files. Second, each cloud server contains files from many users. Hence, it is not feasible to seize servers from a data center without violating the privacy of many other users. Third, even if the data belonging to a particular suspect is identified, separating it from other users' data is difficult. Moreover, other than the cloud provider's word, there is usually no evidence that links a given data file to a particular suspect. For such challenges, clouds cannot be used to store healthcare, business, or national security related data, which require audit and regulatory compliance. In this paper, we systematically examine the cloud forensics problem and explore the challenges and issues in cloud forensics. We then discuss existing research projects and finally, we highlight the open problems and future directions in cloud forensics research area. We posit that our systematic approach towards understanding the nature and challenges of cloud forensics will allow us to examine possible secure solution approaches, leading to increased trust on and adoption of cloud computing, especially in business, healthcare, and national security. This in turn will lead to lower cost and long-term benefit to our society as a whole.
A constraint-based approach to fault management for groupware services

There is no standard model at the service layer. However, fault management to distributed services and applications needs to construct and utilize complex models of the participating objects and their interdependencies. Thus, model-based fault management tools can predict the correct behavior of diagnosed systems and use the resulting predictions to identify faults. When used on-line in real systems, diagnostic tools based on such models should be able to provide prompt response and accurate, comprehensive explanations of the root causes of faults. In this paper we propose to address these requirements: modeling, proactive diagnosis, and explanation. We apply a recent extension to the constraint satisfaction paradigm, called composite constraint satisfaction, to facilitate modeling of complex systems, and we use constraint propagation techniques to support proactive diagnosis and explanation. We demonstrate the applicability of our approach on an example of a basic groupware service, namely, distributed database replication.
The future center as an urban innovation engine

Purpose – The purpose of this article is to describe a future center as an urban innovation engine for the knowledge city, to understand the success factors of a future center and how this success can be replicated systematically in the implementation and development of future centers in the future.Design/methodology/approach – Nine future centers were visited and a longitudinal action research‐based case study was conducted at the regional Be'er Sheva PISGA Future Center in Israel, within the educational domain.Findings – There are 13 conceptual building‐blocks for a future center and the unifying principle is conversations. The PISGA future center put the concept of a future center into action and was guided by six operating principles: values, experiment and learning, organizational structure, partnerships, physical space, and virtual space. They were able to initiate ten new educational projects within the first two years of operation. A conceptual model of a regional future center was developed and t.
Guided search consensus: Large scale point cloud registration by convex optimization

In this paper we propose a point matching algorithm that computes correspondences between images and/or 3D objects in affine camera settings. We formulate the point correspondence problem by minimizing an error function over the set of all binary decisions. This function has two components: a geometric error (akin to retro-projection error) and an image dissimilarity component. Originally a combinatorial problem we obtain its exact solution through a convex relaxation. Hinging on a recent theorem, this solution is derived by carefully designing the minimizing function. The large scale optimization problem is handled by an extremely fast algorithm based on Nesterov's projected gradient method. Experimental results show both computational efficiency and high robustness to large deviations and we demonstrate that it can cope with very hard real situations such as scenes with repetitive patterns. The methodology can be applied seamlessly to both 2D or/and 3D cameras.
Redundancy Elimination Might Be Overrated: A Quantitative Study on Real-World Wireless Traffic

With significant increases in mobile device traffic slated for the foreseeable future, numerous technologies must be embraced to satisfy such demand. Notably, one of the more intriguing approaches has been blending on-device caching and device-to-device (D2D) communications. While various past research has pointed to potentially significant gains (30%+) via redundancy elimination (RE), some skepticism has emerged to whether or not such gains are truly harnessable in practice. The premise of this paper is to explore whether or not significant potential for redundancy elimination exists and whether the rise of video and encryption might blunt said efforts. Critically, we find that absent significant synchronized interests of mobile users, the actual redundancy falls well short of the promising values from the literature. In our paper, we investigate the roots for said shortcomings by exploring RE savings with regards to cache hit characteristics and to what extent client and domain diversity contribute to the realized redundancy savings.
Analyzing User Behavior Using Keystroke Dynamics to Protect Cloud from Malicious Insiders

Nowadays cloud computing is growing vastly as the number of companies are depending mostly on this technology due to its advantages. All the data are stored across the globe and maintained by the cloud service providers i.e., the responsibility of the data is in the hands of cloud providers. The data breach is a biggest problem in cloud as the data are shared across the globe and sensitive information of the customer is stored at some third party storage site. Security of the data is the major concern in cloud from outsiders as well as insiders. Insider attack is the most devastating threat due to the familiarity of the underlying system to the insiders. The proposed approach mitigates this threat by a host based user profiling technique where a key stroke dynamics is used for analyzing the user behavior and a retraining approach is also proposed as the imposter patterns are absent at the time of registration. Retraining boosts the overall system performance in mitigating the insider threat.
DNA Data Compression Based on the Whole Genome Sequence

In order to cope with the rapidly growing genome sequence data, we need a new method for compression. The compression ratios of existing algorithms are just about 1.6 bits per base. Furthermore, it is impossible to compare DNA sequences in their compressed or encoded form. Provided that an anchor point called the whole genome sequence for each organism has been setup in the post genome era, this paper presents a compression method, DNAEncodeWG, based on the whole genome sequence. It finds some regions in the whole genome sequence matching well with a given query sequence and then records the characteristics of the regions and the differences between the two sequences. We have implemented a tool for proving the efficiency and effectiveness of the method.
Answering Any Class of Japanese Non-factoid Question by Using the Web and Example Q&A Pairs from a Social Q&A Website

In this paper, we propose a method of non-factoid Web question-answering that can uniformly deal with any class of Japanese non-factoid question by using a large number of example Q&A pairs. Instead of preparing classes of questions beforehand, the method retrieves already asked question examples similar to a submitted question from a set of Q&A pairs. Then, instead of preparing clue expressions for the writing style of answers according to each question class beforehand, it dynamically extracts clue expressions from the answer examples corresponding to the retrieved question examples. This clue expression information is combined with topical content information from the question to extract appropriate answer candidates. The experimental results showed that the clue expressions obtained from the set of examples improved the accuracy of answer candidate extraction.
Urban Area Classification Using High Resolution Remote Sensing Data: A Hybrid Classification Approach

Increasing urbanization has resulted in reduction of agricultural land. There is immense requirement of keeping track urban development's to avoid depletion of agricultural land. This paper explains urban area classification using remote sensing and GIS Mapping of classification is done with help of top sheet E43D/5, with scale 1:50, 0000 and IRS-P6 LISS-IV image of Feb. 2014 having resolution of 5.8 m and GPS receiver My GPS coordinates is used. Classification methods like supervised and unsupervised both are used and detailed results analysis is done. For doing this the acquired image went through the series of process namely Preprocessing, Classification and Result analysis. Some image enhancement techniques were also performed to improve the satellite imagery for better visual interpretation. ENVI 4.4 image analysis tool were used for data processing and analysis. Maximum Likelihood, Mahalanobis distance, and Isodata classifiers were performed for urban classification in this study. Seven urban classes have been identified from the satellite image classification processes. It is observed that area is covered by barren land, agricultural area (with crops and without crops), hilly area, buildings and water bodies and play ground etc. The experimental results were compared with different supervised and unsupervised classifiers, such as Mahalanobis distance, and Maximum Likelihood and Isodata classifiers respectively. The performances of the classifiers were evaluated in terms of the classification accuracy with respect to the ground truth. The result of the classifications suggests that, each used and covered type were best classified by the Hybrid classification technique. Hybrid classification is done by first applying unsupervised classification like ISODATA classification, followed by various supervised classification techniques like Maximum likelihood, Mahalanobis classification. Hybrid classifier is best classifier of all. Combination of Supervised and Unsupervised classifier results in better accuracy as compared to supervised classification alone.
Power-Saving Design for Server Farms with Response Time Percentile Guarantees

The expense of power cost in server farms has driven the recent power-aware development in both industry and academia. At the same time, a Service Level Agreement (SLA) of service performance between a customer and a service provider is demanded to meet the customer satisfaction. This paper investigates the queueing-theoretical power-saving design strategy for server farms under a given SLA, which in particular is measured in a certain level percentile of the job response time. We consider server farms with servers that are equipped with the capabilities of Dynamic Voltage Scaling (DVFS) and Dynamic Power Management (DPM). We adopt an M/G/1/PS server model, where the job service time distribution is assumed heavy-tailed, as discovered and validated by previous research. We propose a design strategy called Power Tail to minimize the power consumption under the given SLA. Our data confirms that the proposed PowerTail strategy indeed provides statistical guarantee in comparison with existing dynamic DVFS approaches and significantly outperforms the intuitive load-balancing strategy.
Requirements validation by lifting retrenchments in B

Simple retrenchment is briefly reviewed in the B specification language of J.-R. Abrial (1996) as a liberalization of classical refinement, for the formal description of application developments too demanding for refinement. The looser relationships allowed by retrenchment between adjacent models in the development process may capture some of the requirements information of the development. This can make requirements validation more difficult to understand since the locus of requirements should be the models, and not their interrelationships, as far as possible. Hence the universal construction by Banach (2000), originally proposed for simple transition systems, is reformulated in B, in order to "lift" a given retrenchment conceptually, thus retracting such requirements information back to the level of abstraction of the abstract, ideal model. Examples demonstrate the cognitive value of retracting requirements to the abstract level, articulated in a well-understood formal language. This is also seen to yield a more understandable way of comparing alternative retrenchment designs. Some new B syntax in the pre- and postcondition style is presented to facilitate expression of the lifted requirements.
Integrin (cid:2) 2 (cid:3) 1 Promotes Activation of Protein Phosphatase 2A and Dephosphorylation of Akt and Glycogen Synthase Kinase 3 (cid:3)

Serine/threonine kinase Akt is a downstream effector protein of phosphatidylinositol-3-kinase (PI-3K). Many integrins can function as positive modulators of the PI-3K/Akt pathway. Integrin (cid:1) 2 (cid:2) 1 is a collagen receptor that has been shown to induce speciﬁc signals distinct from those activated by other integrins. Here, we found that, in contrast what was found for cells adherent to ﬁbronectin, (cid:1) 2 (cid:2) 1-mediated cell adhesion to collagen leads to dephosphorylation of Akt and glycogen synthase kinase 3 (cid:2) (GSK3 (cid:2) ) and concomitantly to the induction of protein serine/threonine phosphatase 2A (PP2A) activity. PP2A activation can be inhibited by mutation in the (cid:1) 2 cytoplasmic domain and by a function-blocking anti- (cid:1) 2 antibody. Akt can be coprecipitated with PP2A, and coexpression of Akt with PP2Ac (catalytic subunit) inhibits Akt kinase activity. Integrin (cid:1) 2 (cid:2) 1-related activation of PP2A is dependent on Cdc42. These results indicate that cell adhesion to collagen modulates Akt activity via the (cid:1) 2 (cid:2) 1-induced activation of PP2A.