Miracle-dz/UniFAR-FTUs huggingface dataset:
Modeling Problem Solving in Massive Open Online Courses

Massive Open Online Courses (MOOC) have presented a completely new style of learning and teaching that also brings us a massive amount of student behavioral data. Some of this data is exclusive to the MOOC environment. It opens up many possibilities for educators to study a question they have always wanted to answer: how do students solve problems? In this thesis, we present and address some of the numerous challenges one encounters during the process of mining MOOC data to answer this seemingly simple question. We describe in detail, using the data from MITx’s 6.002x Spring 2012 course offering, a large scale, mixed automated and manual process that starts with the re-organization of MOOCdb source data into relevant and retrieval-efficient abstractions we call student resource trajectories and answer type transition matrices. This step must be interleaved with meticulous and painstaking automatic and manual curation of the data to remove errors and irrelevancies while aggregating redundancies, reducing noise and assuring meaningful, trustworthy variables. Regardless, only an estimation of student resource usage behavior during problem solving is available. With all student trajectories for every problem of 6.002X extracted, we demonstrate some analyses of student behaviors for the whole student population. These offer some insight into a problem’s level of difficulty and student behavior around a problem type, such as homework. Next, in order to study how students reached the correct solution to a problem, we categorize problem answers and consider how student move from one incorrect answer to their next attempt. This requires extensive filtering out of irrelevancies and rankings. Detailed knowledge of resources, as would be expected of an instructor, appears to be crucial to understanding the implications of the statistics we derive on frequency of resource usage in general and per attempt. We identify solution equivalence and interpretation also as significant hurdles in obtaining insights. Finally, we try to describe students’ problem solving process in terms of resource use patterns by using hidden Markov modeling with original variable definitions and 3 different variable relationships (graphical structures). We evaluate how well these models actually describe the student trajectories and try to use them to predict up-
Determinantes de la desigualdad en el desempeño educativo en la Argentina [Determinants of the inequality in PISA test scores in Argentina]

Inequality in PISA test scores of Argentinean students is among the highest of the participating countries. This paper explores the determinants of this inequality and quantifies the marginal contribution of characteristics of students and schools. We estimate Multilevel Models of the determinants of PISA 2009 reading results for Argentina and decompose the overall score inequality based on the methodology proposed by Lerman and Yitzhaki (1985) to decompose the Gini coefficient of total income by income source. The main result is that overall test scores inequality is mainly due to the high socioeconomic segregation among Argentinean schools.
Introduction [In Food and agriculture in Ethiopia: Progress and policy challenges]

Indeed, the reality of Ethiopiaâ€™s agriculture and food security situation is complex because of variations across space within Ethiopia as well as variations over time due to changes in policies, weather shocks, and other factors. A complete picture of Ethiopiaâ€™s agriculture and food security must include both the very serious acute and chronic food insecurity problems faced by many Ethiopians and the progress achieved in other areas and at the national level.
Application Layer DDoS Attack Defense Framework for Smart City using SDN

Smart city brings enormous opportunities and exciting challenges. In a smart city, operations and services such as traffic, transport, electric power, and water distribution are monitored, operated, and controlled through ICT based infrastructure, smartly. This allows efficient management of resources and facilitates smooth access to services. However, it also induces stringent requirements and challenges for uninterrupted operation and execution of ICT-based monitoring and controlled infrastructure. Cybersecurity is one of the foremost challenges in a smart city network. That is, protecting the smart city application services from cyber-attacks and ensuring continuity of services is utmost desirable. As smart city services typically comprised of web based applications, application level distributed denial of service (AL-DDoS) attack is a major cybersecurity threat that can have catastrophic impact on an extremely critical smart city network. This paper presents an efficient framework for AL-DDoS attack detection and mitigation for a smart city network. The proposed framework utilizes Software Defined Networking (SDN) paradigm to implement resilient design that ensures continuity of smart city application services. The framework integrates a sound mechanism that distinguishes AL-DDoS attack from legitimate flash crowd. This is a novel framework that addresses the flash crowd attack detection and mitigation in a smart city environment using SDN.
Probability-Based Optimal Control Design for Soft Landing of Short-Stroke Actuators

The impact forces during switching operations of short-stroke actuators may cause bouncing, audible noise, and mechanical wear. The application of soft-landing control strategies to these devices aims at minimizing the impact velocities of their moving components to ultimately improve their lifetime and performance. In this brief, a novel approach for soft-landing trajectory planning, including probability functions, is proposed for optimal control of the actuators. The main contribution of the proposal is that it considers the uncertainty in the contact position, and hence, the obtained trajectories are more robust against system uncertainties. The problem is formulated as an optimal control problem and transformed into a two-point boundary value problem for its numerical resolution. Simulated and experimental tests have been performed using a dynamic model and a commercial short-stroke solenoid valve. The results show a significant improvement in the expected velocities and accelerations at contact with respect to past solutions in which the contact position is assumed to be perfectly known.
Research Trends in Massive Open Online Course (MOOC) Theses and Dissertations: Surfing the Tsunami Wave

Massive Open Online Courses (MOOCs) have attracted a great deal of attention by higher education and private enterprises. MOOCs have evolved considerably since their emergence in 2008, all the while given rise to academic discussions on MOOC impact, design and reach. In an effort to understand MOOCs more comprehensively, this study analyzes theses and dissertations (N = 51) related to MOOCs and published between 2008 and 2015, identifying research trends from these academic documents. Theses and dissertations within this research scope were gathered through a comprehensive search in multiple academic databases. For the purposes of the study, the research employed a systematic review approach. In order to reveal trends in research themes, emphasize theoretical/conceptual backgrounds, research designs and models, first a document analysis was used to collect data and this was followed by a content analysis. Our research findings indicate that MOOC research is generally derived from education, engineering and computer science, as well as information and communication technology related disciplines. Qualitative methodology linked to a case study research model is most common, and the theoretical/conceptual backgrounds are usually distance education related. Remarkably, nearly half of the studies didn’t benefit from any theoretical or conceptual perspectives. In sum, this study presents an evaluation regarding research trends derived from MOOC theses and dissertations, and provides directions for future MOOC research.
Interfacial spin-orbit splitting and current-driven spin torque in anisotropic tunnel junctions

Spin transport in magnetic tunnel junctions comprising a single magnetic layer in the presence of interfacial spin-orbit interaction (SOI) is investigated theoretically. Due to the presence of interfacial SOI, a current-driven spin torque can be generated at the second order in SOI, even in the absence of an external spin polarizer. This torque possesses two components, in-plane and perpendicular to the plane of rotation, that can induce either current-driven {\em magnetization switching} from in-plane to out-of-plane configuration or {\em magnetization precessions}, similarly to Spin Transfer Torque in spin-valves. Consequently, it appears that it is possible to control the magnetization steady state and dynamics by either varying the bias voltage or electrically modifying the SOI at the interface.
On Bayesian Estimation in Mixed Linear Models Using the Gibbs Sampler

Mixed linear models are naturally modelled within the Bayesian framework. Nonetheless, calculation of the marginal posterior distributions of variance components and functions of variance components has proved a challenging technical problem. The purpose of this paper is to show that an adaptive Monte Carlo integration technique known as the Gibbs sampler provides a simple and efficient method for calculating marginal posterior distributions and expectations of fixed and random effects.
Unsupervised Turkish Morphological Segmentation for Statistical Machine Translation

We present our investigations on unsupervised Turkish morphological segmentation (TMS) for statistical machine translation (SMT), which has not been addressed in previous work (Table 1). We perform in vivo testing of the TMS performance in a phrase-based SMT system developed for the Turkish-English task at IWSLT1. We compare unsupervised segmentation against two baselines: (1) no segmentation, i.e., word-based translation, (2) a state-of-the-art supervised segmentation comprising morphological analysis + disambiguation + manually-crafted rules (Mermer et al., 2009) that performed very well in IWSLT 2010. We set out with an existing unsupervised segmentation tool, Morfessor (Creutz and Lagus, 2007). The original search algorithm of Morfessor aims to satisfy the MAP objective by greedily searching for the segmentation that results in the highest posterior probability according to the generative model. However, the greedy search in the high-dimensional combinatorial search space often gets stuck in local optima. We instead propose to approximate the posterior distribution of segmentations via Gibbs sampling. We decide the segmentation location for a word by drawing a sample from the distribution proportional to the posterior probability of the model given the existing state of segmentation for the rest of the words. We ran the Gibbs sampler for 2000 iterations over the (dynamic) sub-word vocabulary. Table 2 shows that Gibbs sampling is able to find better segmentations in terms of model scores (previously unattainable in greedy search). However, this search improvement does not translate over to the translation performance (Table 3). This suggests a model mismatch, which can be expected in this case since the segmentation model uses only monolingual observations. Hence we extend the generative model to incorporate both sides of the parallel corpus via trans-
The 1999-2000 seismic experiment of the swarm of Macas (Ecuador) in relation with a Subandean unexpected wrench fault system

A seismological experiment of 10 portatile short-period stations has been carried out in 1999-2000 around a swarm close to the city of Macas, Ecuador. The corresponding event locations have been correlated with respect to structural geology. Two main trends have been found. One corresponds to the already well established NNESSW trend of the big aftershocks of the Mw=7.
An Improved Design of Contract Net Trust Establishment Protocol

Contract Net Protocol (CNP) is FIPA standardized high level communication protocol which specifies the way software agents should follow while communicating. However it lacks methods for ensuring trust and reliability of the agents participating in the communication. In an earlier paper authors proposed a variation of CNP involving trust establishment feature into it, termed as Contract Net Trust Establishment Protocol (CNTEP). However, efficient communication can not be ensured unless the communicating counterpart is reliable. This fact provided the motivation for the present work, which extends CNTEP and incorporates reliability computation component in it.
Research on Transposition Method and Loss of Multi-Turn Coil in an Induction Motor

Due to the special application and special structure of induction motor, the requirement for winding loss reduction is very strict. To achieve the purpose, the transposition method of odd strands is proposed, and the loss calculation model of the winding with the multi-turn coil is established for the 5.5 MW induction motor. Calculations indicate that the loss of odd strands is about 1440 W lower than that of even strands. In order to investigate the feasibility of transposition method for odd strands per turn side of the multi-turn coil, a laboratory prototype is designed. The simulation results match well with the experiment results, which will provide a reference for the winding design and winding loss calculation of induction motor.
Inhibitory punktów kontrolnych w niedrobnokomórkowym raku płuca — ku praktyce codziennej

Immunoterapia z zastosowaniem lekow blokujących punkty kontrolne zdaje sie rewolucjonizowac leczenie nowotworow litych, w tym raka pluca. Blokery szlaku PD-1, PD-L1 wykazaly skutecznośc w zakresie dlugotrwalego przezycia w zaawansowanym raku pluca z przerzutami. U indywidualnych chorych osiąga sie kilkuletnie przezycia. W leczeniu raka pluca zarejestrowano nivolumab, pembrolizumab i atezolizumab. Obserwacje z praktyki klinicznej wskazują na podobną skutecznośc tych lekow, jak w probach klinicznych. Efekty leczenia zalezą od stanu sprawności. Wiek, plec, typ histologiczny, obecnośc przerzutow do mozgu nie wplywaly na wyniki leczenia. Leczenie antagonistami punktow kontrolnych jest bezpieczne i dobrze tolerowane, dzialania niepoządane wiązą sie z zapaleniami o podlozu autoimmunizacyjnym. Powaznym i niekiedy śmiertelnym powiklaniem moze byc zapalenie pecherzykow plucnych (pneumonitis), choc zazwyczaj poddaje sie leczeniu glikokortykosteroidami. W celu odpowiedniej kwalifikacji chorych do leczenia ocenia sie ekspresje PD-L1 na komorkach raka. Tak zwane guzy „gorące”, ze znaczną ekspresją PD-L1 i bogatym naciekiem z limfocytow cytotoksycznych zdają sie lepiej odpowiadac na immunoterapie niz guzy „zimne”.
Information Platforms and the Rise of the Data Scientist

AT THE AGE OF 17, I WAS FIRED FROM MY JOB AS A CASHIER AT SCOTT’S GROCERY STORE IN FORT Wayne, Indiana. With only two months remaining before my freshman year of college, I saw in my unemployment an opportunity. Instead of telling my parents that I had been fired, I continued to leave the house every afternoon in my cashier’s outfit: black pants, black shoes, white shirt, and smock. To my parents, I looked ready for some serious coupon scanning; in reality, I was pulling 10-hour shifts reading at the public library.
Development of embedded Linux system on LPC2210-based board

This paper describes the characteristics of ARM7 and uCLinux operating system and discusses the developing procedures of the platform based on ARM7 and uCLinux.Applying the platform developed, the procedure of an application programming based on NFS is demonstrated.The platform developed will adapted into the development of data processing for radioactive aerosols and gaseous monitoring system.
Asymptotic Optimality of Constant-Order Policies in Joint Pricing and Inventory Control Models

We consider a traditional joint pricing and inventory control problem with lead times, which has been extensively studied in the literature but is notoriously difficult to solve due to the complex structure of the optimal policy. In this work, rather than analyzing the optimal policy, we propose a class of so-called constant-order dynamic pricing policies, which are quite different from base-stock heuristics, the primary focus in the existing literature. Under such a policy, a constant-order amount of new inventory is ordered every period and a pricing decision is made based on the on-hand inventory. The policy is independent of the lead time and does not suffer from the curse of dimensionality. We prove that the best constant-order dynamic pricing policy is asymptotically optimal as the lead time grows large, which is exactly the setting in which the problem becomes computationally intractable due to the curse of dimensionality. As a main methodological contribution, we implement the so-called vanishing discount factor approach and establish the convergence to a long-run average random yield inventory model with zero lead time and ordering capacities by its discounted counterpart as the discount factor goes to one, non-trivially extending the previous results in Federgruen and Yang (2014) that analyze a similar model but without capacity constraints.
APC‐EDFA‐based scintillation‐suppressed photodetection in satellite optical communication

This article proposes automatic power control (APC)‐erbium‐doped fiber amplifier (EDFA)‐based scintillation‐suppressed photodetection in satellite optical communication (SOC). It is mainly based on the dynamic gain characteristic of APC‐EDFA. In order to improve the performance, high pass filter (HPF) and Manchester on‐off‐keying (M‐OOK) are introduced as supplemental methods. The proposed scheme is evaluated experimentally under various turbulence channel strengths. The experimental results show that the scintillation effect is suppressed using APC‐EDFA with pump power reduction compared to gain saturation, and an approximate 5.83 dB signal‐to‐noise ratio improvement is obtained compared to adaptive threshold decision with instantaneous turbulence channel state information under a scintillation index of 0.2990.
Overview of High-Step-Up DC–DC Converters for Renewable Energy Sources

ABSTRACT To utilize the power generated from renewable energy sources and use it in stand-alone or grid integrated application, power conditioning unit (PCU) is required. The main consideration in designing a PCU is lower cost, higher reliability, higher efficiency, and robust operation. One of the major components of PCU is high-step-up and high-efficient DC–DC converter. This paper provides a comprehensive topological review of different high-step-up DC–DC converter topologies. A wide variety of DC–DC conversion topologies (both transformerless and isolated) with wide voltage conversion ratio have been reviewed. To improve the converter efficiency, various soft-switching techniques are implemented. This paper intends to serve as one of the convenient reference for future researchers.
The new transit town : best practices in transit-oriented development

Transit-oriented development (TOD) seeks to maximize access to mass transit and nonmotorized transportation with centrally located rail or bus stations surrounded by relatively high-density commercial and residential development. New Urbanists and smart growth proponents have embraced the concept and interest in TOD is growing, both in the United States and around the world. New Transit Town brings together leading experts in planning, transportation, and sustainable design -- including Scott Bernstein, Peter Calthorpe, Jim Daisa, Sharon Feigon, Ellen Greenberg, David Hoyt, Dennis Leach, and Shelley Poticha -- to examine the first generation of TOD projects and derive lessons for the next generation. It offers topic chapters that provide detailed discussion of key issues along with case studies that present an in-depth look at specific projects. Topics examined include: the history of projects and the appeal of this form of development; a taxonomy of TOD projects appropriate for different contexts and scales; the planning, policy and regulatory framework of "successful" projects; obstacles to financing and strategies for overcoming those obstacles; issues surrounding traffic and parking; the roles of all the actors involved and the resources available to them; performance measures that can be used to evaluate outcomes; Case Studies include Arlington, Virginia (Roslyn-Ballston corridor); Dallas (Mockingbird Station and Addison Circle); historic transit-oriented neighborhoods in Chicago; Atlanta (Lindbergh Center and BellSouth); San Jose (Ohlone-Chynoweth); and San Diego (Barrio Logan). New Transit Town explores the key challenges to transit-oriented development, examines the lessons learned from the first generation of projects, and uses a systematic examination and analysis of a broad spectrum of projects to set standards for the next generation. It is a vital new source of information for anyone intersted in urban and regional planning and development, including planners, developers, community groups, transit agency staff, and finance professionals.
Best scheme of design dynamic website: Apache+PHP+MySQL

APACHE is a web server of the most abroad application,PHP is a sort of script language of similarly ASP server end,and MySQL is small database system software,it suit to website buid.Apache+PHP+MySQL are not only an open source project as free,but also can be supported by Linux,UNIX,OS/2 and Windows operating system.So,this sort of combination is the best solve scheme of design dynamic website.First,the installation and configuration of Apache+PHP+MySQL software is introduced.Second,particular design and realize of developing principle and system function of web shop are given using Apache+PHP+MySQL combination below Windows operating system platform.
Controlling a Servo Motor Using EEG Signals from the Primary Motor Cortex

Brain Computer Interface means the group of processes in which the generated signals of EEG in the human brain can be interpreted and transferred to control an external device. In this paper, a novel method is adopted to control the rotation of a servo motor via EEG signals extracted from the human brain cortex. These signals have to pass through a processing procedure consisting mainly noise filtration and signal normalizing. The processed signal is fed to Arduino, which in turn controls the servo motor rotation.
Dynamic social graphs : mining and modeling

In recent decades, we have faced an explosion of social data, in which unprecedented variety of personal information has become accessible to the public. Social data consists of data on individuals and on interactions among individuals. Once we integrate these two categories of social data, social graphs emerge. In this research, two main research challenges were addressed: how to turn social data into social graphs and how to analyze the evolving social graphs. In this thesis, effective data-driven approaches were proposed for turning heterogeneous social data into social graphs that successfully revealed new demographic patterns in real historical data corpora.