Miracle-dz/UniFAR-FTUs huggingface dataset:
First year pre-service teachers' mathematical content knowledge: methods of solution for a ratio question

In this article, pre-service teachers' mathematics content knowledge is explored through the analysis of two items about ratio from a Mathematical Competency, Skills and Knowledge Test. Pre-service teachers' thinking strategies, common errors and misconceptions in their responses are presented and discussed. Of particular interest was the range and nature of common incorrect responses for one wholewhole ratio question. Results suggested pre-service teachers had difficulty interpreting a worded multi-step, ratio (scale) question, with errors relating to ratio and/or conversion of measurement knowledge. These difficulties reveal underdevel - oped knowledge of mathematical structure and mathematical connections as well as an inability to deconstruct key components of a mathematical problem. Most pre-service teachers also lacked knowledge of standard procedures and methods of solutions.
Coherent and Noncoherent Detection of CPFSK

Continuous phase frequency shift keying (CPFSK) is potentially an attractive modulation scheme for use on channels whose performance is limited by thermal noise. In this paper results for the performance available with CPFSK are given for coherent detection and noncoherent detection with arbitrary modulation indices and arbitrary observation intervals. This work serves two purposes. First, it provides interesting, new results for the noncoherent detection of CPFSK which indicate that the performance of such a system can be better than the performance of coherent PSK. Secondly, it provides a complete analysis of the performance of CPFSK at high SNR as well as low SNR and thereby unifies and extends the results previously available.
The use by students of formative feedback for improving their writing : a study of student self-observation reports in an academic writing module at the University of Zululand.

This study analyses students' use of formative feedback through a case study of a foundation-type academic literacy module at the University of Zululand. The research paradigm incorporates both a critical and a constructivist perspective, and a qualitative approach. The data collected were transcripts of interviews conducted with students towards the end of the third term, 2004, for the module. During the interviews the students described how they used respondent feedback on short, draft pieces of writing. They referred to their portfolio of writing which was with them. Students write short pieces, or endnotes, after each lecture in order to show their understanding of academic concepts based on the content of Political Philosophy; they must rewrite after carefully noting respondents' comments on their work; and they, with tutor supervision, write group endnotes for responders. The meta-level understanding underpinning the modules is an academic literacies approach. The transcripts were analysed using discourse analysis. Findings are that the students interviewed tend to use the feedback as if they are corrections, rather than what the feedback ideally aims at, which is by a writing dialogue, to help students to develop students' awareness of the discipline's conventions for academic writing, together and through construction of coherent meaning in their writing. The students' interpretive framing of their use of the respondent
Pervasive translation in Mycobacterium tuberculosis

Most bacterial ORFs are identified by automated prediction algorithms. However, these algorithms often fail to identify ORFs lacking canonical features such as a length of >50 codons or the presence of an upstream Shine-Dalgarno sequence. Here, we use ribosome profiling approaches to identify actively translated ORFs in Mycobacterium tuberculosis. Most of the ORFs we identify have not been previously described, indicating that the M. tuberculosis transcriptome is pervasively translated. The newly described ORFs are predominantly short, with many encoding proteins of ≤50 amino acids. Codon usage of the newly discovered ORFs suggests that most have not been subject to purifying selection, and hence do not contribute to cell fitness. Nevertheless, we identify 90 new ORFs (median length of 52 codons) that bear the hallmarks of purifying selection. Thus, our data suggest that pervasive translation of short ORFs in Mycobacterium tuberculosis serves as a rich source for the evolution of new functional proteins.
A sequential Bayesian generalization of the Jelinski–Moranda software reliability model

The Jelinski–Moranda model of software reliability is generalized by introducing a negative‐binomial prior distribution for the number of faults remaining, together with a Gamma distribution for the rate at which each fault is exposed. This model is well suited to sequential use, where a sequence of reliability forecasts is made in the process of testing or using the software. We also investigate replacing the Gamma distribution with a worst‐case assumption about failure rates (the worst‐case failure rate in models such as this is not infinite, since faults with large failure rates are immediately discovered and removed). © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006
Towards an advanced nonlinear rotorcraft flight control system design

Traditional rotorcraft flight control designs rely heavily on plant models which have been linearized about various operating set points. These designs are only valid for operating conditions close to the original trim points and suffer performance degradations for significant deviations. Consequently, several linear controllers are designed and scheduled to cover the operational flight envelope. An alternate approach that uses the inherent nonlinearities of the plant model may provide improved performance. Described herein are the initial results of a rotorcraft control design methodology that uses an aircraft-model-based transformation to convert the input-output map of the original nonlinear plant into a linear time-invariant system. The validity of the design technique for attitude stabilization is evaluated in a high-fidelity computer simulation of the UH-60 Black Hawk helicopter. <<ETX>>
High-Speed Implementation of the KECCAK Hash Function on FPGA

Because of the weakening of the widely-used SHA-1 hash algorithm and concerns over the similarly-structured algorithms of the SHA-2 family; the US NIST has initiated the SHA-3 contest in order to select a suitable drop-in replacement. In this paper we review KECCAK hash function’s algorithm and apply several methods to improve the performance with respect to throughput, frequency and timing. In trying to improve any of these parameters one may adversary affect the other factors. Different architectures are coded in VHDL and implemented on FPGAs and are compared in terms of speed.
Economics of mixed-species forestry with ecosystem services

The Faustmann–Hartman setup is widely established for specifying the economics of forest values besides timber, but it is criticized as restrictive for capturing diversity values. We show that extending the model to cover diversity attributes, i.e., mixed species and internal heterogeneity within species, is not enough to overcome these restrictions. Additionally, it is necessary to extend forest harvesting regimes to cover thinning, continuous cover forestry, and the management of commercially useless trees. Restrictions in the Faustmann–Hartman setup are first shown analytically with optimized thinning but without tree size structures. The empirical significance of these findings is shown by a model that includes four tree species, tree size structures, an extended set of forest management activities, a detailed description of harvesting costs, and a measure for stand diversity as a key factor behind ecosystem services. We show how an optimal harvesting regime, net revenues, wood output, and stand diversity depend on model flexibility, economic parameters, and the valuation of ecosystem services. In a setup allowing flexible management regimes, the costs of reaching a specified level of ecosystem services are negligible compared with those of the Faustmann–Hartman specification.
Hybrid ray optical models for the penetration of radio waves into enclosed spaces

With the growing interest for broadband mobile services in 3rd generation mobile communication networks, the investigation of radio transmission into vehicles and buildings is getting more important. Models for the propagation into vehicles and buildings enable the calculation of the field strength or received power inside these objects. The inner structure of the vehicles (e.g. metal parts) and buildings (inner walls, furniture) as well as the surroundings (other vehicles, buildings) must be considered, and also different construction materials must be taken into account. A deterministic ray tracing approach has been developed, enabling the computation of the transition from an urban scenario to an indoor scenario and vice versa, thus allowing a very accurate computation of the field strength or received power inside vehicles or buildings. Due to the ray tracing technique, the approach can also be utilized to evaluate wideband properties of the mobile radio channel by computing its impulse response. In order to validate such propagation models, measurements inside and outside a building were made.
Nanosecond plasmas in water: ignition, cavitation and plasma parameters

Nanosecond plasmas in liquids play an important role in the field of decontamination, electrolysis or plasma medicine. The understanding of these very dynamic plasmas requires information about the temporal variation of species densities and temperatures. This is analyzed by monitoring nanosecond pulsed plasmas that are generated by high voltages (HVs) between 14 and 26 kV and pulse lengths of 10 ns applied to a tungsten tip with 50 μm diameter immersed in water. Ignition of the plasma causes the formation of a cavitation bubble that is monitored by shadowgraphy to measure the dynamic of the created bubble and the sound speed of the emitted acoustic waves surrounding this tungsten tip. The temporal evolution of the bubble size is compared with cavitation theory yielding good agreement for an initial bubble radius of 25 μm with an initial pressure of 5 × 108 Pa at a temperature of 1200 K for a HV of 20 kV. This yields an initial energy in the range of a few 10−5 J that varies with the applied HV. The dissipated energy by the plasma drives the adiabatic expansion of water vapor inside the bubble from its initial supercritical state to a low pressure, low temperature state at maximum bubble expansion reaching values of 103 Pa and 50 K, respectively. These predictions from cavitation theory are corroborated by optical emission spectroscopy. After igniting the nanosecond plasma, the electrical power oscillates in the feed line between HV pulser and plasma chamber with a ring down time of the order of 60 ns. These reflected pulses re-ignite a plasma inside the expanding bubble periodically. Broadband emission due to recombination and Bremsstrahlung becomes visible within the first 30 ns. At later times, line emission dominates. Stark broadening of the spectral lines of Hα (656 nm) and OI (777 nm) is evaluated to determine both the electron density and the electron temperature in these re-ignited plasmas.
Selfish behavior and stability of the internet: a game-theoretic analysis of TCP

For years, the conventional wisdom [7, 22] has been that the continued stability of the Internet depends on the widespread deployment of "socially responsible" congestion control. In this paper, we seek to answer the following fundamental question: If network end-points behaved in a selfish manner, would the stability of the Internet be endangered? We evaluate the impact of greedy end-point behavior through a game-theoretic analysis of TCP. In this "TCP Game" each flowattempts to maximize the throughput it achieves by modifying its congestion control behavior. We use a combination of analysis and simulation to determine the Nash Equilibrium of this game. Our question then reduces to whether the network operates efficiently at these Nash equilibria.Our findings are twofold. First, in more traditional environments -- where end-points use TCP Reno-style loss recovery and routers use drop-tail queues -- the Nash Equilibria are reasonably efficient. However, when endpoints use more recent variations of TCP (e.g., SACK) and routers employ either RED or drop-tail queues, the Nash equilibria are very inefficient. This suggests that the Internet of the past could remain stable in the face of greedy end-user behavior, but the Internet of today is vulnerable to such behavior. Second, we find that restoring the efficiency of the Nash equilibria in these settings does not require heavy-weight packet scheduling techniques (e.g., Fair Queuing) but instead can be done with a very simple stateless mechanism based on CHOKe [21].
Observation and Modeling of Seawater Exchange in a Strait-Basin System in the Seto Inland Sea, Japan

The seawater exchange is closely related to the spreading of pollutant and the water quality in coastal seas. The Seto Inland Sea is a semi-enclosed coastal sea which has a series of broad basins and narrow straits, and the along-channel outflows from the strait located at the center of the channel toward east and west may play an important role in seawater exchange. In this study, flows along the boundary between Bisan Seto which is located at the center of the Seto Inland Sea and the adjacent basin called Harima Nada were measured using a ship-mounted Acoustic Doppler Current Profiler and residual flows were obtained by removing tidal currents. The survey results showed significant volume flux of the along-channel outflows from Bisan Seto toward Harima Nada. A numerical model based on Princeton Ocean Model was also used in order to analyze the driving forces of the along-channel outflow. The outflow was well reproduced using the model which was driven by tide and horizontal density gradient between the strait and basin, suggesting that these possibly induce the seawater exchange in the Seto Inland Sea.
A Metaphoric Examination of the Meaning of Marriage

Bu arastirmanin temel amaci evli, bekar, nisanli ve bosanmis bireylerin evliligin anlamina iliskin algilarinin metafor analizi yoluyla incelenmesidir. Arastirmada belirtilen sorulara yanit aranmaya calisilmistir; 1. Arastirma kapsaminda evli, bekâr, nisanli ve bosanmis bireylerin evlilik anlami kavramina iliskin gelistirdikleri metaforlar nelerdir? 2. Arastirma kapsamindaki katilimcilarin cinsiyet, egitim duzeyi ve medeni durum gibi demografik ozelliklerine gore evliligin anlamina iliskin gelistirdikleri metaforlar nasil farklilasmaktadir? Arastirmanin calisma grubu amacli ornekleme yontemlerinden maksimum cesitlilik ornekleme teknigi ile belirlenmistir. Calisma grubu 110 kisiden olusmaktadir. 110 bireyin 66’si kadin 44’u erkek olmak uzere 53 evli, 50’si bekâr, 5’i bosanmis, 2’si nisanli/sozlu bireylerdir. Katilimcilarin evlilik olgusuna dair gelistirdikleri metaforlari belirlemek amaciyla forma “Evlilik …………… gibidir, cunku……………. ” cumlesi konularak katilimcilardan bu cumleyi tamamlamalari istenmistir. Veriler metafor analizi ile incelenmistir. 110 katilimcinin gelistirmis oldugu 101 adet metaforun tanimlanmasindan sonra metaforlarin olusturdugu 11 adet kavramsal kategorinin gelistirilmesi tamamlanmistir. 11 kategori su isimlerle siralanmistir; mutluluk, guven, gercekcilik, uretkenlik, caba-emek-mucadele, engellenmislik-yoksunluk, karsiliklilik-beklenti, birliktelik-dayanisma, bilinmezlik-belirsizlik, risk ve gelisim.
Interaction, Reflection and Learning at a Distance

The author's experiences as an online student are presented as a case study to examine the relationship between interaction, reflection and learning in distance education. Reflection as a dimension of experiential learning theory is summarised and examples of its use in distance education are discussed. Recommendations for course design that promotes the understanding of theoretical issues through personal experience are proposed.
Code-switching in second language teaching of French

Although code-switching has attracted a considerable amount of attention for quite some time, the issue of linguistic switch in foreign language teaching has not been a major subject of scientific study. Using a qualitative approach to individual examples of linguistic switch among three second language teachers of French in Sweden, this article, although highly preliminary, attempts to highlight and explain some of the features of code-switching in the foreign language classroom.
Improvization and strategic risk-taking in informal learning with digital media literacy

The city provides a rich array of learning opportunities for young children. However, in many urban schools, often it can be logistically difficult to get young children out of the building. But when elementary children are encouraged to view the city as a classroom and use digital media to explore and represent their neighborhoods, they can be inspired by the unpredictable events of daily life to ask naïve, critical and sometimes troubling questions. This paper presents a case study of a teacher in an informal media literacy learning environment who worked with a group of 9-year olds in Philadelphia. It documents the experience of a novice teacher who, flummoxed by an accidental encounter between her students and a homeless person, transformed an uncomfortable experience into a teachable moment. Children's questions about homelessness became the organizing frame for learning experience, as the instructor helped children make sense of the information on the Internet, analyze popular culture films and news media, and conduct interviews with community leaders and advocates for the homeless. The inquiry process resulted in a collaboratively produced multimedia project, created by children. The case study has implications for pre- and in-service teacher education for digital and media literacy. This paper suggests that improvization and strategic risk-taking must be conceptualized as a set of socio-emotional and experiential competencies that teachers need when using digital media in an urban community as a tool for learning.
Ventricular tachycardia in patients with type 1 myotonic dystrophy: a case series

Abstract Background Type 1 myotonic dystrophy (DM1) is associated with a variety of cardiac conduction abnormalities and the frequent need for permanent pacing. However, the role of ventricular tachycardia (VT) and the implied risk of sudden cardiac death (SCD) is poorly understood. Case summary This study examined a 56-patient DM1 cohort of men and women, and identified five patients (two females and three males) with ventricular arrhythmias (8.9%). Patients were reviewed on a case-by-case basis, with their clinical presentation and management of VT and the associated cardiomyopathy indicated. Patient cardiac function was determined by 12-lead electrocardiogram, 48-h Holter monitor, and transthoracic echocardiography. These patients were therefore suitable candidates for implantable cardioverter-defibrillator implantation and received these devices; four of the five patients also received cardiac resynchronization therapy. Medical therapies included angiotensin converting enzyme inhibition, mineralocorticoid receptor antagonist, and following device implantation, beta-blocker therapy was initiated. Discussion Our case series demonstrates the prevalence of VT in patients with DM1 highlighting the associated risks of SCD in this patient population. The burden of ventricular arrhythmias, advanced conduction disease, and cardiomyopathy are best treated with a combination of device and medical therapies.
Quantifying the effects of the cochlear amplifier on temporal and average-rate information in the auditory nerve

An active mechanism referred to as the cochlear amplifier is believed to be responsible for sharp tuning and excellent sensitivity in the normal auditory system, and is impaired or absent in many common forms of sensorineural hearing loss. The cochlear amplifier is thought to benefit normal-hearing listeners, especially in complex listening environments in which hearing-impaired listeners have difficulty even with hearing aids. A modeling approach was developed to relate nonlinear physiological response properties associated with the cochlear amplifier to human psychophysical performance. Quantitative methods combined analytical and computational population models of the auditory-nerve (AN) with statistical decision theory to evaluate performance limits imposed by the random nature of AN discharges (modeled by a nonstationary Poisson process). A new theoretical approach was developed to predict performance for psychophysical tasks that use random-noise stimuli to mask signal information. The ability of temporal and average-rate information in the AN to account for human performance was evaluated for several listening tasks for which the cochlear amplifier has been suggested to be significant. The benefit of the cochlear amplifier for extending the auditory system’s dynamic range was evaluated in terms of AN information available for encoding changes in stimulus level. An analytical model included nonlinear gain, level-dependent phase, and high-, mediumand low-spontaneous-rate AN fibers. Both nonlinear-phase and average-rate information were required to encode levels up to 120 dB SPL based on a narrow range of AN characteristic frequencies. A physiologically realistic mechanism to decode nonlinear gain and phase cues is monaural, across-frequency coincidence detection. Level-discrimination performance of a coincidence-counter population matched human performance across the entire dynamic range of hearing at both low and high frequencies. Results suggest that the cochlear amplifier is beneficial for encoding sound level within narrow frequency regions, and has only a small influence on simple listening tasks in quiet. The cochlear amplifier alters tuning within the normal auditory system based on the spectral and temporal configuration of the stimulus. The influences of compression and suppression on psychophysical measures of auditory frequency selectivity were evaluated. Implications for the interpretation of psychophysical methods for estimating auditory filters are discussed. Thesis Supervisor: Laurel H. Carney, Ph.D. Title: Associate Professor of Biomedical Engineering, Boston University
An analysis of TCP processing overhead

The authors report a preliminary analysis of the processing overhead of the transport protocol TCP (Transmission Control Protocol) in which they estimate the possible performance range of the protocol. The analysis was performed by compiling a version of TCP and counting the number of the instructions in the common path. The analysis suggests that fewer than 200 instructions are required to process a TCP packet in the normal case. This number is small enough to support very high-speed transmission if it were the major overhead. The authors offer some speculations about the actual source of processing overhead in network protocols. <<ETX>>
The problem of learning long-term dependencies in recurrent networks

The authors seek to train recurrent neural networks in order to map input sequences to output sequences, for applications in sequence recognition or production. Results are presented showing that learning long-term dependencies in such recurrent networks using gradient descent is a very difficult task. It is shown how this difficulty arises when robustly latching bits of information with certain attractors. The derivatives of the output at time t with respect to the unit activations at time zero tend rapidly to zero as t increases for most input values. In such a situation, simple gradient descent techniques appear inappropriate. The consideration of alternative optimization methods and architectures is suggested. <<ETX>>