nils-herrmann/clean_scirepeval huggingface dataset:
Accelerating K-12 computational thinking using scaffolding, staging, and abstraction

We describe a three-stage model of computing instruction beginning with a simple, highly scaffolded programming environment (Kodu) and progressing to more challenging frameworks (Alice and Lego NXT-G). In moving between frameworks, students explore the similarities and differences in how concepts such as variables, conditionals, and looping are realized. This can potentially lead to a deeper understanding of programming, bringing students closer to true computational thinking. Some novel strategies for teaching with Kodu are outlined. Finally, we briefly report on our methodology and select preliminary results from a pilot study using this curriculum with students ages 10-17, including several with disabilities.
A Comprehensive Survey on Pose-Invariant Face Recognition

The capacity to recognize faces under varied poses is a fundamental human ability that presents a unique challenge for computer vision systems. Compared to frontal face recognition, which has been intensively studied and has gradually matured in the past few decades, Pose-Invariant Face Recognition (PIFR) remains a largely unsolved problem. However, PIFR is crucial to realizing the full potential of face recognition for real-world applications, since face recognition is intrinsically a passive biometric technology for recognizing uncooperative subjects. In this article, we discuss the inherent difficulties in PIFR and present a comprehensive review of established techniques. Existing PIFR methods can be grouped into four categories, that is, pose-robust feature extraction approaches, multiview subspace learning approaches, face synthesis approaches, and hybrid approaches. The motivations, strategies, pros/cons, and performance of representative approaches are described and compared. Moreover, promising directions for future research are discussed.
Structured low-rank approximation and its applications

Fitting data by a bounded complexity linear model is equivalent to low-rank approximation of a matrix constructed from the data. The data matrix being Hankel structured is equivalent to the existence of a linear time-invariant system that fits the data and the rank constraint is related to a bound on the model complexity. In the special case of fitting by a static model, the data matrix and its low-rank approximation are unstructured. We outline applications in system theory (approximate realization, model reduction, output error, and errors-in-variables identification), signal processing (harmonic retrieval, sum-of-damped exponentials, and finite impulse response modeling), and computer algebra (approximate common divisor). Algorithms based on heuristics and local optimization methods are presented. Generalizations of the low-rank approximation problem result from different approximation criteria (e.g., weighted norm) and constraints on the data matrix (e.g., nonnegativity). Related problems are rank minimization and structured pseudospectra.
Cross-library API recommendation using web search engines

Software systems are often built upon third party libraries. Developers may replace an old library with a new library, for the consideration of functionality, performance, security, and so on. It is tedious to learn the often complex APIs in the new library from the scratch. Instead, developers may identify the suitable APIs in the old library, and then find counterparts of these APIs in the new library. However, there is typically no such cross-references for APIs in different libraries. Previous work on automatic API recommendation often recommends related APIs in the same library. In this paper, we propose to mine search results of Web search engines to recommend related APIs of different libraries. In particular, we use Web search engines to collect relevant Web search results of a given API in the old library, and then recommend API candidates in the new library that are frequently appeared in the Web search results. Preliminary results of generating related C# APIs for the APIs in JDK show the feasibility of our approach.
Subtitle-free Movie to Script Alignment

Scripts of movies and TV videos, offer a number of possibilities for video understanding: they can provide supervisory information for identifying characters  or learning actions ; they enable text-based retrieval and search ; they enable a scene level organization of the video material , etc. The typical method of aligning a script (or transcript) with TV or movie videos, is by applying dynamic time warping with the subtitles, as introduced by Everingham et al. . However, subtitles are not readily available for many old films, silent movies and non-European language videos. In this paper, our objective is the visual alignment between TV/movie videos and their scripts, without using subtitles. Achieving such an alignment increases the scope and applicability of script-based approaches to videos with little or no spoken dialogue. The challenge of the problem is in the comparison and matching of visual information of the video with descriptions given in the script. These descriptions generally involve objects and actions for which visual recognition is not yet mature. Our approach is to combine several cues, both visual and auditory, which in themselves are not quite reliable, but when combined provide sufficiently strong constraints for a full alignment. We pose the problem as one of multi-state labelling of a sequence of shots, where the states for each shot correspond to the sentences of the script. For a correct alignment, each sentence should compete for the right shot to fall into. The voting of a shot should depend on common features that can be extracted from both the sentence and the shot. Towards this end, we extract three clues from each shot/sentence: < Location,Face,Speech >. Location recognition helps in localizing sentences to the shots belonging to the given scene. We begin by locating stock-shots using a nearduplicate detection technique. This specifies the start of the scene. The location of each shot is then recognised using a Bag-of-Visual-Words  based SVM classifier. By combining the results from both, we obtain the temporal segmetation of the video. It is more likely that a sentence belongs to a shot where the speaker of the sentence is visible. To ascertain the presence of the particular character in a shot, we detect and recognize faces across the shot. The detected faces are matched against a set of exemplars for each character. A Kernel-SVM using the min-min distance between face tracks is learnt for each person. The classifier with the best score gives the label for the faces in the shot. Further evidence of sentence-shot correspondence could be obtained from speech recognition. We recognize the speech of each shot using a commercial speech recognizer. Though the actual recognition performance is quite poor, the limited matches do help in the alignment. Independently, each of the audio-visual recognition modules are not accurate enough to align the movie with the script. We thus integrate all the clues into a local assignment cost d(i, j) as
Aggregate and Verifiably Encrypted Signatures from Bilinear Maps

An aggregate signature scheme is a digital signature that supports aggregation: Given n signatures on n distinct messages from n distinct users, it is possible to aggregate all these signatures into a single short signature. This single signature (and the n original messages) will convince the verifier that the n users did indeed sign the n original messages (i.e., user i signed message Mi for i = 1, . . . , n). In this paper we introduce the concept of an aggregate signature, present security models for such signatures, and give several applications for aggregate signatures. We construct an efficient aggregate signature from a recent short signature scheme based on bilinear maps due to Boneh, Lynn, and Shacham. Aggregate signatures are useful for reducing the size of certificate chains (by aggregating all signatures in the chain) and for reducing message size in secure routing protocols such as SBGP. We also show that aggregate signatures give rise to verifiably encrypted signatures. Such signatures enable the verifier to test that a given ciphertext C is the encryption of a signature on a given message M . Verifiably encrypted signatures are used in contract-signing protocols. Finally, we show that similar ideas can be used to extend the short signature scheme to give simple ring signatures.
C R ] 4 J ul 2 01 7 A general framework for Bitcoin analytics

Modern cryptocurrencies exploit decentralised ledgers — the so-called blockchains — to record a public and unalterable history of transactions. These ledgers represent a rich, and increasingly growing, source of information, in part of difficult interpretation and undisclosed meaning. Many analytics, mostly based on ad-hoc engineered solutions, are being developed to discover relevant knowledge from these data. We introduce a framework for the development of custom analytics on Bitcoin — the most preeminent cryptocurrency — which also allows to integrate data within the blockchain with data retrieved form external sources. We illustrate the flexibility and effectiveness of our analytics framework by means of paradigmatic use cases.
As real as real? Macroeconomic behavior in a large-scale virtual world

This article proposes an empirical test of whether aggregate economic behavior maps from the real to the virtual. Transaction data from a large commercial virtual world – the first such data set provided to outside researchers – is used to calculate metrics for production, consumption and money supply based on real-world definitions. Movements in these metrics over time were examined for consistency with common theories of macroeconomic change. The results indicated that virtual economic behavior follows real-world patterns. Moreover, a natural experiment occurred, in that a new version of the virtual world with the same rules came online during the study. The new world’s macroeconomic aggregates quickly grew to be nearly exact replicas of those of the existing worlds, new media & society
Migrating code with statistical machine translation

In the era of mobile computing, developers often need to migrate code written for one platform in a programming language to another language for a different platform, e.g., from Java for Android to C# for Windows Phone. The migration process is often performed manually or semi-automatically, in which developers are required to manually define translation rules and API mappings. This paper presents semSMT, an automatic tool to migrate code written in Java to C#. semSMT utilizes statistical machine translation to automatically infer translation rules from existing migrated code, thus, requires no manual defining of rules. The video demonstration on semSMT can be found on YouTube at http://www.youtube.com/watch?v=aRSnl5-7vNo.
Electric field effect in atomically thin carbon films.

We describe monocrystalline graphitic films, which are a few atoms thick but are nonetheless stable under ambient conditions, metallic, and of remarkably high quality. The films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands, and they exhibit a strong ambipolar electric field effect such that electrons and holes in concentrations up to 10(13) per square centimeter and with room-temperature mobilities of approximately 10,000 square centimeters per volt-second can be induced by applying gate voltage.
A First Look at Music Composition using LSTM Recurrent Neural Networks

In general music composed by recurrent neural networks (RNNs) suffers from a lack of global structure. Though networks can learn note-by-note transition probabilities and even reproduce phrases, attempts at learning an entire musical form and using that knowledge to guide composition have been unsuccessful. The reason for this failure seems to be that RNNs cannot keep track of temporally distant events that indicate global music structure. Long Short-Term Memory (LSTM) has succeeded in similar domains where other RNNs have failed, such as timing & counting and CSL learning. In the current study I show that LSTM is also a good mechanism for learning to compose music. I compare this approach to previous attempts, with particular focus on issues of data representation. I present experimental results showing that LSTM successfully learns a form of blues music and is able to compose novel (and I believe pleasing) melodies in that style. Remarkably, once the network has found the relevant structure it does not drift from it: LSTM is able to play the blues with good timing and proper structure as long as one is willing to listen.
Autonomous Interface Agents

Two branches of the trend towards “agents” that are gaining currency are inre~ace agents, software that actively assists a user in operating an interactive interface, and autonomous agents, software that takes action without user intervention and operates concurrently, either while the user is idle or taking other actions. These two branches are related, but not identical, and are often lumped together under the single term “agent”. Much agent work can be classified as either being an interface agent, but not autonomous, or as an autonomous agent, but not operating directly in the interface. We show why it is important to have agents that are both interface agents and autonomous agents. We explore some design principles for such agents, and illustrate these principles with a description of Letizia, an autonomous interface agent that makes real-time suggestions for Web pages that a user might be interested in browsing.
Multi-Story Indoor Floor Plan Reconstruction via Mobile Crowdsensing

The lack of floor plans is a critical reason behind the current sporadic availability of indoor localization service. Service providers have to go through effort-intensive and time-consuming business negotiations with building operators, or hire dedicated personnel to gather such data. In this paper, we propose Jigsaw, a floor plan reconstruction system that leverages crowdsensed data from mobile users. It extracts the position, size, and orientation information of individual landmark objects from images taken by users. It also obtains the spatial relation between adjacent landmark objects from inertial sensor data, then computes the coordinates and orientations of these objects on an initial floor plan. By combining user mobility traces and locations where images are taken, it produces complete floor plans with hallway connectivity, room sizes, and shapes. It also identifies different types of connection areas (e.g., escalators and stairs) between stories, and employs a refinement algorithm to correct detection errors. Our experiments on three stories of two large shopping malls show that the 90-percentile errors of positions and orientations of landmark objects are about 1~2m and 5~9°, while the hallway connectivity and connection areas between stories are 100 percent correct.
FPGASort: a high performance sorting architecture exploiting run-time reconfiguration on fpgas for large problem sorting

This paper analyses different hardware sorting architectures in order to implement a highly scaleable sorter for solving huge problems at high performance up to the GB range in linear time complexity. It will be proven that a combination of a FIFO-based merge sorter and a tree-based merge sorter results in the best performance at low cost. Moreover, we will demonstrate how partial run-time reconfiguration can be used for saving almost half the FPGA resources or alternatively for improving the speed. Experiments show a sustainable sorting throughput of 2GB/s for problems fitting into the on-chip FPGA memory and 1 GB/s when using external memory. These values surpass the best published results on large problem sorting implementations on FPGAs, GPUs, and the Cell processor.
A memory optimization technique for software-managed scratchpad memory in GPUs

With the appearance of massively parallel and inexpensive platforms such as the G80 generation of NVIDIA GPUs, more real-life applications will be designed or ported to these platforms. This requires structured transformation methods that remove existing application bottlenecks in these platforms. Balancing the usage of on-chip resources, used for improving the application performance, in these platforms is often non-intuitive and some applications will run into resource limits. In this paper, we present a memory optimization technique for the software-managed scratchpad memory in the G80 architecture to alleviate the constraints of using the scratchpad memory. We propose a memory optimization scheme that minimizes the usage of memory space by discovering the chances of memory reuse with the goal of maximizing the application performance. Our solution is based on graph coloring. We evaluated our memory optimization scheme by a set of experiments on an image processing benchmark suite in medical imaging domain using NVIDIA Quadro FX 5600 and CUDA. Implementations based on our proposed memory optimization scheme showed up to 37% decrease in execution time comparing to their naïve GPU implementations.
Bayesian model selection for group studies

Bayesian model selection (BMS) is a powerful method for determining the most likely among a set of competing hypotheses about the mechanisms that generated observed data. BMS has recently found widespread application in neuroimaging, particularly in the context of dynamic causal modelling (DCM). However, so far, combining BMS results from several subjects has relied on simple (fixed effects) metrics, e.g. the group Bayes factor (GBF), that do not account for group heterogeneity or outliers. In this paper, we compare the GBF with two random effects methods for BMS at the between-subject or group level. These methods provide inference on model-space using a classical and Bayesian perspective respectively. First, a classical (frequentist) approach uses the log model evidence as a subject-specific summary statistic. This enables one to use analysis of variance to test for differences in log-evidences over models, relative to inter-subject differences. We then consider the same problem in Bayesian terms and describe a novel hierarchical model, which is optimised to furnish a probability density on the models themselves. This new variational Bayes method rests on treating the model as a random variable and estimating the parameters of a Dirichlet distribution which describes the probabilities for all models considered. These probabilities then define a multinomial distribution over model space, allowing one to compute how likely it is that a specific model generated the data of a randomly chosen subject as well as the exceedance probability of one model being more likely than any other model. Using empirical and synthetic data, we show that optimising a conditional density of the model probabilities, given the log-evidences for each model over subjects, is more informative and appropriate than both the GBF and frequentist tests of the log-evidences. In particular, we found that the hierarchical Bayesian approach is considerably more robust than either of the other approaches in the presence of outliers. We expect that this new random effects method will prove useful for a wide range of group studies, not only in the context of DCM, but also for other modelling endeavours, e.g. comparing different source reconstruction methods for EEG/MEG or selecting among competing computational models of learning and decision-making.
Enhancement of electric motor thermal management through axial cooling methods: A materials approach

Switched Reluctance Motors are becoming increasingly popular in the automotive industry for their capability for high-speed operation, low manufacturing cost and relatively simple and robust design. Like other electric machines, SRM requires a thermal management system to dissipate the excessive thermal energy generated during use. By utilizing advanced materials, it is possible to develop an axial cooling system for SRM. This paper discusses the role of axial cooling and the development of improved materials and their contribution to the axial cooling application.
Using Semantic Web Technologies for Exploratory OLAP: A Survey

This paper describes the convergence of some of the most influential technologies in the last few years, namely data warehousing (DW), on-line analytical processing (OLAP), and the Semantic Web (SW). OLAP is used by enterprises to derive important business-critical knowledge from data inside the company. However, the most interesting OLAP queries can no longer be answered on internal data alone, external data must also be discovered (most often on the web), acquired, integrated, and (analytically) queried, resulting in a new type of OLAP, exploratory OLAP. When using external data, an important issue is knowing the precise semantics of the data. Here, SW technologies come to the rescue, as they allow semantics (ranging from very simple to very complex) to be specified for web-available resources. SW technologies do not only support capturing the “passive” semantics, but also support active inference and reasoning on the data. The paper first presents a characterization of DW/OLAP environments, followed by an introduction to the relevant SW foundation concepts. Then, it describes the relationship of multidimensional (MD) models and SW technologies, including the relationship between MD models and SW formalisms. Next, the paper goes on to survey the use of SW technologies for data modeling and data provisioning, including semantic data annotation and semantic-aware extract, transform, and load (ETL) processes. Finally, all the findings are discussed and a number of directions for future research are outlined, including SW support for intelligent MD querying, using SW technologies for providing context to data warehouses, and scalability issues.
Eigen-Optimization on Large Graphs by Edge Manipulation

Large graphs are prevalent in many applications and enable a variety of information dissemination processes, e.g., meme, virus, and influence propagation. How can we optimize the underlying graph structure to affect the outcome of such dissemination processes in a desired way (e.g., stop a virus propagation, facilitate the propagation of a piece of good idea, etc)? Existing research suggests that the leading eigenvalue of the underlying graph is the key metric in determining the so-called epidemic threshold for a variety of dissemination models. In this paper, we study the problem of how to optimally place a set of edges (e.g., edge deletion and edge addition) to optimize the leading eigenvalue of the underlying graph, so that we can guide the dissemination process in a desired way. We propose effective, scalable algorithms for edge deletion and edge addition, respectively. In addition, we reveal the intrinsic relationship between edge deletion and node deletion problems. Experimental results validate the effectiveness and efficiency of the proposed algorithms.