Miracle-dz/UniFAR-FTUs huggingface dataset:
Economics of Femtocells

Femtocells or home base stations are a proposed solution to the problem of degraded indoor service from the macrocell base station in future 4G data networks. In this paper, we study user incentives for the adoption of femtocells and their resulting impact on network operator revenues. We model a monopolist network operator who offers the option of macrocell access or macro+femtocell access to a population of users who possess linear valuations for the data throughput. We compare the revenues from two possible spectrum schemes for femtocell deployment; the split spectrum scheme, where femtocells and macrocells operate on different frequencies and do not interfere, and, the common spectrum scheme, where they operate on the same frequencies (partially or fully) and interfere. Our results suggest that the optimal pricing scheme always charges a higher price for the femtocell service, i.e., the operator does not offer any subsidies for adoption. Yet, at the optimal prices, almost full adoption of femtocells is achieved even for many common spectrum schemes that degrade macrocell capacity. Femtocell deployments provide huge revenue gains when macrocell capacities are low. However, in this range, even common spectrum schemes that heavily degrade the macrocell capacity perform comparably to the split spectrum scheme. Some common spectrum schemes with moderate macrocell degradation yield revenues comparable or higher than the split spectrum scheme at all levels of macrocell congestion.
Integration of supercapacitors as transient energy buffer in automotive power nets

Load fluctuations in an automotive power net can cause significant perturbations of the supply voltage. A quality improvement for the electrical power supply can be achieved by connecting supercapacitors in parallel to the battery as a transient energy buffer. Effective voltage stabilisation and steadier generator output current were observed in an experimental investigation of such a power net modification. In addition to the increase of the peak power capability of the power net, charge throughput and rms-current in the battery were reduced. A concept and operation strategy aiming automotive requirements for the integration of supercapacitors into the power net are proposed. The resulting system was named "dynamic power assistance".
Galaxy Morphologies in the Hubble Ultra Deep Field: Dominance of Linear Structures at the Detection Limit

Galaxies in the Hubble Ultra Deep Field (UDF) larger than 10 pixels (0.″3) have been classified according to morphology, and their photometric properties are presented. There are 269 spiral, 100 elliptical, 114 chain, 126 double-clump, 97 tadpole, and 178 clump-cluster galaxies. We also cataloged 30 B-band and 13 V-band dropouts and calculated their star formation rates. Chains, doubles, and tadpoles dominate the other types at faint magnitudes. The fraction of obvious bars among spirals is ~10%, a factor of 2-3 lower than in other deep surveys. The distribution function of axial ratios for elliptical galaxies is similar to that seen locally, suggesting that ellipticals relaxed quickly to a standardized shape. The distribution of axial ratios for spiral galaxies is significantly different than locally, having a clear peak at ~0.55 instead of a nearly flat distribution. The falloff at small axial ratio occurs at a higher value than locally, indicating thicker disks by a factor of ~2. The falloff at high axial ratio could be from intrinsic triaxial shapes or selection effects. Inclined disks should be more highly sampled than face-on disks near the surface brightness limit of a survey. Simple models and data distributions demonstrate these effects. The decreased numbers of obvious spiral galaxies at high redshifts could be partly the result of surface brightness selection.
A Comparison of VHDL and Statecharts-Based Modeling Approaches

To verify functional correctness of circuits, software models can be used. Functional blocks can be modeled at different levels of abstraction, from a data path level to the gate level. Depending on the level of abstraction, different formalisms are used: early specification is best done using uninterpreted formalisms (such as Petri nets or Statecharts), while later design stages require a more detailed description. In this paper, we describe a model of the MIPS/SAB R3223, a read-write buffer for MIPS R3000-based systems. This circuit was modeled in both VHDL and a high-level graphic design front end (SPeeDCHART) to compare the complexity of the modeling process, the resulting models and their performance.
Stellar Activity on the Young Suns of Orion: COUP Observations of K5-7 Pre-Main-Sequence Stars

In 2003 January, the Chandra Orion Ultradeep Project (COUP) detected about 1400 young stars during a 13.2 day observation of the Orion Nebula Cluster (ONC). This paper is a study of the X-ray properties of a well-defined sample of 28 solar-mass ONC stars based on COUP data. Our goals are to characterize the magnetic activity of analogs of the young Sun and thereby to improve understanding of the effects of solar X-rays on the solar nebula during the era of planet formation. Given the length of the COUP observation we are able to clearly distinguish characteristic and flare periods for all stars. We find that active young suns spend 70% of their time in a characteristic state with relatively constant flux and magnetically confined plasma with temperatures kT2 ≃ 2.1 × kT1. During characteristic periods, the 0.5-8 keV X-ray luminosity is about 0.03% of the bolometric luminosity. One or two powerful flares per week with peak luminosities log LX ~ 30-32 ergs s-1 are typically superposed on this characteristic emission accompanied by heating of the hot plasma component from ≃2.4 to ≃7 keV at the flare peak. The energy distribution of flares superposed on the characteristic emission level follows the relationship dN/dE ∝ E-1.7. The flare rates are consistent with the production of sufficiently energetic protons to spawn a spallogenic origin of some important short-lived radionuclides found in ancient meteorites. The X-rays can ionize gas in the circumstellar disk at a rate of 6 × 10-9 ionizations per second at 1 AU from the central star, orders of magnitude above cosmic-ray ionization rates. The estimated energetic particle fluences are sufficient to account for many isotopic anomalies observed in meteoritic inclusions.
Notes on the verlinde formula in nonrational conformal field theories

We review and extend evidence for the validity of a generalized Verlinde formula, in particular, nonrational conformal field theories. We identify a subset of representations of the chiral algebra in nonrational conformal field theories that give rise to an analogue of the relation between modular S-matrices and fusion coefficients in rational conformal field theories. To that end we review and extend the Cardy-type brane calculations in bosonic and supersymmetric Liouville theory (and its duals) as well as in H{sub 3}{sup +}. We analyze the three-point functions of Liouville theory and of H{sub 3}{sup +} in detail to directly identify the fusion coefficients from the operator product expansion. Moreover, we check the validity of a proposed generic formula for localized brane one-point functions in nonrational conformal field theories.
Architecting Citywide Ubiquitous Wi-Fi Access

Cities around the world are currently considering building expensive Wi-Fi infrastructure. In urban areas, resident operated Wi-Fi access points (APs) are dense enough to achieve ubiquitous Internet access, provided we can induce the hosts to provide guest Wi-Fi access. However, sharing Wi-Fi involves taking on responsibility for the guest’s actions. Our main contribution is a novel mechanism to handoff the host’s responsibility to a trusted point by tunneling the guest’s packets through it. The tunnel also guarantees that the guest’s traffic cannot be subverted by malicious hosts. Using tunneling as a primitive, we show how to architect a citywide cooperative for safely sharing Wi-Fi with legitimate guests. We offer this as an economically viable alternative to investing millions in new infrastructure.
Lossless image compression using 2D allpass filters

In this paper, a reversible integer-to-integer wavelet transform based on non-separable 2D allpass filters is proposed for lossless image coding. The number of rounding operations included in the reversible wavelet transform is reduced by using non-separable 2D allpass filters, thus it is expected to get better coding performance. The lossless coding performance of the proposed reversible wavelet transform is evaluated and compared with the conventional separable wavelet transforms. It is shown from the experimental results that the proposed non-separable 2D reversible wavelet transform can achieve better lossless coding performance than the conventional separable wavelet transforms, including the D-5/3 wavelet transform in the JPEG 2000.
Level crossing analysis of BER for adaptive MIMO OFDM systems

In this paper we consider the level crossing rates (LCRs) of bit error rates (BERs) across the frequency bins of a multiple-input multiple-output (MIMO) system with orthogonal frequency division multiplexing (OFDM) operating over frequency selective Rayleigh fading environments. In particular, we consider each eigenmode as a random process in the frequency domain and compute the LCR for the BER of transmission down the eigenchannels of the MIMO OFDM channel. Many extensions to this work are possible including LCRs in time as well as in frequency. The accuracy of the analytical approximations are verified by Monte Carlo simulations.
Robust modular Bulk Built-in Current Sensors for detection of transient faults

Soft error resilience is an increasingly important requirement of integrated circuits realized in CMOS nanometer technologies. Among the several approaches, Bulk Built-in Current Sensors (BBICS) offer a promising solution as they are able to detect particle strikes immediately after its occurrence. Based on this idea we demonstrate a novel modular BBICS (mBBICS) that tackles the main problems of these integrated sensors - area, leakage, and robustness. Simulations based on a predictive nanometer technology indicate competitive response times for high performance applications at the cost of 25% area overhead and very low power penalty. Thereby, all simulated particle strikes that lead to transient faults could be detected. Additionally reliability analysis proved the robustness of the proposed mBBICS against wide variations of temperature and process parameters.
Creating Creative Learning Environments by Creative Partnerships Programme—Evaluation of the Creative Partnerships Pilot Mathematics Programme in Pécs

A Creative Partnerships programme is focused on the long-term relationship between creative practitioners and schools. Creative professionals from various branches (of arts) help students master different types of knowledge and skills. Creative practitioners bring new expectations, which clearly challenge students. But it is not only students that are jerked out of the rut of daily routine by the new learning process—schools as a whole and mainly teachers are highly affected. Creative Partnerships has developed a pedagogical approach known as the “high functioning classroom” which encourages teachers to change their classroom practice so that lessons are replete with challenges that relate learning to real-life situations; where students are engaged physically and socially, as well as emotionally and intellectually; and where students’ own experiences, observations and questions take centre stage. The transformation of teaching and learning is based on creative processes which are channelled into classrooms and school life. Techniques applied in the methodologies of teaching various subjects are derived from artistic practices. Whilst working in the classroom with the students, the artist remains an artist, and the teacher remains a teacher. The programme does not offer arts education. What the Creative Partnerships programme does is to prepare artists to work with teachers and students to bring about sustainable changes in teachers’ teaching practice. The aim of the present paper is to present the main results of qualitative and quantitative research measuring the impact of the Creative Partnerships pilot programme on certain competencies, reading skills development and maths knowledge of the participating (socially disadvantaged) students.
Divergence Involving Global Regulatory Gene Mutations in an Escherichia coli Population Evolving under Phosphate Limitation

Many of the important changes in evolution are regulatory in nature. Sequenced bacterial genomes point to flexibility in regulatory circuits but we do not know how regulation is remodeled in evolving bacteria. Here, we study the regulatory changes that emerge in populations evolving under controlled conditions during experimental evolution of Escherichia coli in a phosphate-limited chemostat culture. Genomes were sequenced from five clones with different combinations of phenotypic properties that coexisted in a population after 37 days. Each of the distinct isolates contained a different mutation in 1 of 3 highly pleiotropic regulatory genes (hfq, spoT, or rpoS). The mutations resulted in dissimilar proteomic changes, consistent with the documented effects of hfq, spoT, and rpoS mutations. The different mutations do share a common benefit, however, in that the mutations each redirect cellular resources away from stress responses that are redundant in a constant selection environment. The hfq mutation lowers several individual stress responses as well the small RNA–dependent activation of rpoS translation and hence general stress resistance. The spoT mutation reduces ppGpp levels, decreasing the stringent response as well as rpoS expression. The mutations in and upstream of rpoS resulted in partial or complete loss of general stress resistance. Our observations suggest that the degeneracy at the core of bacterial stress regulation provides alternative solutions to a common evolutionary challenge. These results can explain phenotypic divergence in a constant environment and also how evolutionary jumps and adaptive radiations involve altered gene regulation.
Firewall rule with token bucket as a DDoS protection tool

The subject of this article are the security problems of network resources in computer networks. Presently the main problem of computer networks are Distributed Denial of Service attacks which can block them. The methods suggested by the literature that mostly base on using firewall and IDS/IPS mechanisms to fight the attacks are not sufficient enough. In this article the author presents a new method for counteracting DDoS attacks - firewall rule with token bucket implementation from Quality of Services method. This new concept is different than previous one, because it gives possibility for user to finish they work which was started before the DDoS attack occurs and they do not suffer from DDoS attacks. The proposed method has already been tested. The results presented in this article suggest that the method could be applied in practice. This article is a part of authors papers focused on IT security.
ConSnap: Taking continuous snapshots for running state protection of virtual machines

The reliability of data and services hosted in a virtual machine (VM) is a top concern in cloud computing environment. Continuous snapshots reduces the data loss in case of failures, and thus is prevailing for providing protection for long-running systems. However, existing methods suffer from long VM downtime, long snapshot interval and significant performance overhead. In this paper, we present ConSnap, a system designed to enable taking fine-grained continuous snapshots of virtual machines without compromising VM performance. First, ConSnap adopts the COW (copy-on-write) manner to save the memory pages in a lazy way, and thus decrease the snapshot interval to dozens of milliseconds. Second, we only save the incremental memory pages on the basis of the last snapshot in each epoch to reduce the snapshot duration, and thus mitigate VM performance loss. Third, we propose a multi-granularity space reclamation strategy, which merges the unused snapshot files to achieve storage space saving, as well as fast recovery. We have implemented ConSnap on QEMU/KVM and conducted several experiments to verify its effectiveness. Compared with the stop-and-copy based incremental snapshots, ConSnap reduces the performance loss by 71.1% ~ 10.2% under Compilation workload, and 14.5% ~ 4.7% for the Ftp workload, when the interval varies from 1s to 60s.
Comparative study of porous hydroxyapatite/chitosan and whitlockite/chitosan scaffolds for bone regeneration in calvarial defects

Hydroxyapatite (HAP; Ca10(PO4)6(OH)2) and whitlockite (WH; Ca18Mg2(HPO4)2(PO4)12) are widely utilized in bone repair because they are the main components of hard tissues such as bones and teeth. In this paper, we synthesized HAP and WH hollow microspheres by using creatine phosphate disodium salt as an organic phosphorus source in aqueous solution through microwave-assisted hydrothermal method. Then, we prepared HAP/chitosan and WH/chitosan composite membranes to evaluate their biocompatibility in vitro and prepared porous HAP/chitosan and WH/chitosan scaffolds by freeze drying to compare their effects on bone regeneration in calvarial defects in a rat model. The experimental results indicated that the WH/chitosan composite membrane had a better biocompatibility, enhancing proliferation and osteogenic differentiation ability of human mesenchymal stem cells than HAP/chitosan. Moreover, the porous WH/chitosan scaffold can significantly promote bone regeneration in calvarial defects, and thus it is more promising for applications in tissue engineering such as calvarial repair compared to porous HAP/chitosan scaffold.
Bio password — Keystroke dynamic approach to secure mobile devices

The objective of the paper is to provide how a biopassword is using keystroke dynamics technology to deliver security for mobile devices to monitor and authenticate users. Mobile devices have outgrown their initial use for telephony and now have added functionality such web browsing and m-commerce. Depending on the specific area of usage of the device, the importance and hence the sensitivity of the data stored in it changes. As a result, there is a need to secure the data and to protect the devices from loss or theft. The users of these mobile devices have authentication method of PIN i.e. (Personal Identification Numbers). But, with the problems associated with using PIN is Easy to Crack password's, Sharing the passwords, using the same password for different devices, the need for using sophisticated methods allowing only the legitimate users the access to data and identifying and preventing imposters manifolds many times as the mobility of the computing devices changes. In this paper we examine an emerging biometric technique that aims to identify users based on analyzing habitual rhythm patterns in the way they type.
Goal Tracking and Goal Attainment: A Natural Language Means of Achieving Adjustable Autonomy

Intelligent mobile robots that interact with humans must be able to exhibit adjustable autonomy, that is the ability to dynamically adjust the level of autonomy of an agent depending on the situation. When intelligent robots require close interactions with humans, they will require modes of communication that enhance the ability for humans to communicate naturally and that allow greater interaction. Our previous work examined the use of multiple modes of communication, specifically natural language and gestures, to disambiguate the communication between a human and a robot. In this paper, we propose using context predicates to keep track of various goals during human-robot interactions. These context predicates allow the robot to maintain multiple goals, each with possibly different levels of required autonomy. They permit direct human interruption of the robot, while allowing the robot to smoothly return to a high level of autonomy.
Worm Burden-Dependent Disruption of the Porcine Colon Microbiota by Trichuris suis Infection

Helminth infection in pigs serves as an excellent model for the study of the interaction between human malnutrition and parasitic infection and could have important implications in human health. We had observed that pigs infected with Trichuris suis for 21 days showed significant changes in the proximal colon microbiota. In this study, interactions between worm burden and severity of disruptions to the microbial composition and metabolic potentials in the porcine proximal colon microbiota were investigated using metagenomic tools. Pigs were infected by a single dose of T. suis eggs for 53 days. Among infected pigs, two cohorts were differentiated that either had adult worms or were worm-free. Infection resulted in a significant change in the abundance of approximately 13% of genera detected in the proximal colon microbiota regardless of worm status, suggesting a relatively persistent change over time in the microbiota due to the initial infection. A significant reduction in the abundance of Fibrobacter and Ruminococcus indicated a change in the fibrolytic capacity of the colon microbiota in T. suis infected pigs. In addition, ∼10% of identified KEGG pathways were affected by infection, including ABC transporters, peptidoglycan biosynthesis, and lipopolysaccharide biosynthesis as well as α-linolenic acid metabolism. Trichuris suis infection modulated host immunity to Campylobacter because there was a 3-fold increase in the relative abundance in the colon microbiota of infected pigs with worms compared to naïve controls, but a 3-fold reduction in worm-free infected pigs compared to controls. The level of pathology observed in infected pigs with worms compared to worm-free infected pigs may relate to the local host response because expression of several Th2-related genes were enhanced in infected pigs with worms versus those worm-free. Our findings provided insight into the dynamics of the proximal colon microbiota in pigs in response to T. suis infection.
Vertical distribution of aerosols in the vicinity of Mexico City during MILAGRO-2006 Campaign

Abstract. On 7 March 2006, a mobile, ground-based, vertical pointing, elastic lidar system made a North-South transect through the Mexico City basin. Column averaged, aerosol size distribution (ASD) measurements were made on the ground concurrently with the lidar measurements. The ASD ground measurements allowed calculation of the column averaged mass extinction efficiency (MEE) for the lidar system (1064 nm). The value of column averaged MEE was combined with spatially resolved lidar extinction coefficients to produce total aerosol mass concentration estimates with the resolution of the lidar (1.5 m vertical spatial and 1 s temporal). Airborne ASD measurements from DOE G-1 aircraft made later in the day on 7 March 2006, allowed the evaluation of the assumptions of constant ASD with height and time used for estimating the column averaged MEE. The results showed that the aerosol loading within the basin is about twice what is observed outside of the basin. The total aerosol base concentrations observed in the basin are of the order of 200 μg/m3 and the base levels outside are of the order of 100 μg/m3. The local heavy traffic events can introduce aerosol levels near the ground as high as 900 μg/m3. The article presents the methodology for estimating aerosol mass concentration from mobile, ground-based lidar measurements in combination with aerosol size distribution measurements. An uncertainty analysis of the methodology is also presented.