bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical impact of EUS elastography followed by contrast-enhanced EUS in patients with focal pancreatic masses and negative EUS-guided FNA
Authors: Iordache Sevastiţa , Costache Mădălin Ionuţ , Popescu Carmen Florina , Streba Costin Teodor , Cazacu Sergiu , Săftoiu Adrian
Published: February 2016

Aims: It is well known that endoscopic ultrasound guided fine needle aspiration (EUS-FNA) has a high sensitivity (over 85%) and specificity (100%) for diagnosis of pancreatic cancer. The aim of the study was to establish a EUS based clinical diagnostic algorithm in patients with pancreatic masses and negative cytopathology after EUS-FNA, based on previously published results and cut-offs of real-time elastographic (RTE) EUS and contrast-enhanced harmonic (CEH) EUS. Material and methods: We included in the study a subgroup of 50 consecutive patients with focal pancreatic masses which underwent EUS examinations with negative EUS-FNA. RTE-EUS and CEH-EUS were performed sequentially in all patients. The sensitivity, specificity and accuracy of these methods were calculated separately. A clinical decision algorithm based on elastography followed by CEH was established. Results: For the diagnosis of possible malignancy, the sensitivity, specificity and accuracy of RTE-EUS were: 97.7%, 77.4%, and 84% respectively. CEH-EUS had similar results: 89.5%, 80.7%, and 84%, respectively. In 25 patients with soft/mixed appearance during elastography,sequential assessment using contrast-enhanced EUSwas performed. The specificity of CEH-EUS for detection of chronic pancreatitis in this sub-set of patients was excellent (100%). In other 25 patients with hard appearance in elastography (low strain) CEH-EUS had an excellent specificity (100%) and accuracy (93%) in the detection of pancreatic cancer. Conclusions: The proposed algorithm with sequential use of elastography followed by CEH could be a good clinical tool in the set of patients with negative EUS-FNA results for the differentiation between benign and malignant focal pancreatic masses.
Ultrasound in diagnosis of anatomical variation of anterior and posterior tibial arteries.
Authors: Zheng Miao , Chen Chuang , Qiu Qianyi , Wu Changjun
Published: February 2016

Aims: Knowledge about branching pattern of the popliteal artery is very important in any clinical settings involving the anterior and posterior tibial arteries. This study aims to elucidate the anatomical variation patterns and common types of anterior tibial artery (ATA) and posterior tibial arteries (PTA) in the general population in China. Material and methods: Anatomical variations of ATA, PTA, and peroneal artery were evaluated with ultrasound in a total of 942 lower extremity arteries in 471 patients. Results: Three patterns of course in the PTA were ultrasonographically identified:  1) PTA1: normal anatomy with posterior tibial artery entering tarsal tunnel to perfuse the foot (91.5%),  2) PTA2: tibial artery agenetic, and replaced by communicating branches of peroneal artery entering tarsal tunnel above the medial malleolus to perfuse the foot (5.9%), and 3) PTA3: hypoplastic or aplastic posterior tibial artery communicating above the medial malleolus with thick branches of peroneal artery to form a common trunk entering into the tarsal tunnel (2.4%). In cases where ATA  was hypoplastic or aplastic, thick branches of the peroneal artery replaced the anterior tibial artery to give rise to dorsalis pedis artery, with a total incidence of 3.2 % in patients, and were observed more commonly in females than in males. Hypoplastic or aplastic termini of ATA and PTA, with perfusion of the foot solely by the peroneal artery, was identified in 1 case. In another case, both communicating branches of the peroneal artery and PTA entered the tarsal tunnel to form lateral and medial plantar arteries.Conclusions: Anatomical variation of ATA and PTA is relatively common in the normal population. Caution should be exercised with these variations when preparing a peroneal artery vascular pedicle flap grafting. Ultrasound evaluation provides accurate and reliable information on the variations.
Clostridium difficileileitis in a patient, after total colectomy
Authors: Tarasiuk-Rusek Aneta , Shah Kairav J
Published: February 2016

This is a case of a 63-year-old, post total colectomy patient, who presented to the hospital with watery diarrhoea, abdominal cramping and fevers. On admission, the patient was haemodynamically stable and febrile.Clostridium difficilePCR was sent and tested positive. CT of the abdomen revealed diffuse thickening of the distal small bowel to the level of the anastomosis and mesenteric oedema consistent with infectious enteritis. The patient was started on vancomycin orally as well as flagyl intravenously. Because of an ileus, he initially was treated with bowel rest and a NG tube. Surgical consult was obtained early with no intervention. The patient's symptoms progressively resolved over the next 7 days of hospitalisation, and he was discharged home.
Exploring the peri-, chemo-, and regioselectivity of addition of technetium metal oxides of the type TcO3L (L = Cl–, O–, OCH3, CH3) to substituted ketenes: a DFT computational study
Authors: Ahmed Issahaku , Tia Richard , Adei Evans
Published: February 2016

The addition of TcO3L (L = Cl, O–, OCH3, CH3) to substituted ketenes along various addition pathways was studied with density functional theory calculations to explore the peri-, chemo-, and regioselectivity of the reactions. In the reactions of TcO3L with dimethyl ketene, the results show that for L = O– and CH3, [1 + 1] addition to form a triplet zwitterionic intermediate is the preferred first step; for L = Cl, the [3 + 2]C=C addition across the O–Tc–Cl bond is the preferred first step and for L = OCH3 the [3 + 2]C=C addition across the O–Tc–OCH3 bond is the preferred first step. In the reactions of TcO3Cl with substituted ketenes, [1 + 1] addition to form a triplet zwitterionic intermediate is the preferred first step for X = Ph, CN, and Cl; the [3 + 2]C=C addition across the O–Tc–O bond of the complex is the preferred first step for X = H, while the [3 + 2]C=C addition across the O–Tc–CH3 bond is the preferred first step. Reactions involving a change in the oxidation state of metal have high activation barriers, while reactions that do not involve a change in oxidation state have low activation barriers. Reactions of ketenes with TcO3L complexes have lower activation barriers for the preferred addition pathways than those of the ReO3L complexes reported in the literature. Thus, the TcO3L complexes may be better catalysts for the activation of the C=C bonds of substituted ketenes than the reported ReO3L complexes.
Non-singular plane curves with an element of “large” order in its automorphism group
Authors: Badr Eslam , Bars Francesc
Published: February 2016

Let [Formula: see text] be the moduli space of smooth, genus [Formula: see text] curves over an algebraically closed field [Formula: see text] of zero characteristic. Denote by [Formula: see text] the subset of [Formula: see text] of curves [Formula: see text] such that [Formula: see text] (as a finite nontrivial group) is isomorphic to a subgroup of [Formula: see text] and let [Formula: see text] be the subset of curves [Formula: see text] such that [Formula: see text], where [Formula: see text] is the full automorphism group of [Formula: see text]. Now, for an integer [Formula: see text], let [Formula: see text] be the subset of [Formula: see text] representing smooth, genus [Formula: see text] curves that admit a non-singular plane model of degree [Formula: see text] (in this case, [Formula: see text]) and consider the sets [Formula: see text] and [Formula: see text].

In this paper we first determine, for an arbitrary but a fixed degree [Formula: see text], an algorithm to list the possible values [Formula: see text] for which [Formula: see text] is non-empty, where [Formula: see text] denotes the cyclic group of order [Formula: see text]. In particular, we prove that [Formula: see text] should divide one of the integers: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] or [Formula: see text]. Secondly, consider a curve [Formula: see text] with [Formula: see text] such that [Formula: see text] has an element of “very large” order, in the sense that this element is of order [Formula: see text], [Formula: see text], [Formula: see text] or [Formula: see text]. Then we investigate the groups [Formula: see text] for which [Formula: see text] and also we determine the locus [Formula: see text] in these situations. Moreover, we work with the same question when [Formula: see text] has an element of “large” order: [Formula: see text], [Formula: see text] or [Formula: see text] with [Formula: see text] an integer.
Cost-Sensitive Probabilistic Contingent Planning for Web Service Composition
Authors: Markou George , Refanidis Ioannis
Published: February 2016

This article presents a cost sensitive probabilistic contingent planning approach for automated semantic web service composition, under the assumptions that the execution of each web service incurs some cost; its alternative outcomes along with their probabilities of occurring are known in advance; and actions do not involve delete effects. The implemented planner, MAPPPA2, produces a contingent plan in the form of a decision tree, by integrating multiple alternative deterministic plans computed by solving a determinized version of the original problem. Both the generation of the alternative deterministic plans, as well as the merging process attempt to maximize the expected utility of the final contingent plan. The article presents evaluation results regarding the approach, based on three web service composition domains.
Using Contextual Topic Model for a Query-Focused Multi-Document Summarizer
Authors: Yang Guangbing
Published: February 2016

Oft-decried information overload is a serious problem that negatively impacts the comprehension of information in the digital age. Text summarization is a helpful process that can be used to alleviate this problem. With the aim of seeking a novel method to enhance the performance of multi-document summarization, this study proposes a novel approach to analyze the problem of multi-document summarization based on a mixture model, consisting of a contextual topic model from a Bayesian hierarchical topic modeling family for selecting candidate summary sentences, and a regression model in machine learning for generating the summary. By investigating hierarchical topics and their correlations with respect to the lexical co-occurrences of words, the proposed contextual topic model can determine the relevance of sentences more effectively, recognize latent topics, and arrange them hierarchically. The quantitative evaluation results from a practical application demonstrates that a system implementing this model can significantly improve the performance of summarization and make it comparable to state-of-the-art summarization systems.
Fine-Tuning of UAV Control Rules for Spraying Pesticides on Crop Fields: An Approach for Dynamic Environments
Authors: Faiçal Bruno S. , Pessin Gustavo , Filho Geraldo P. R. , Carvalho André C. P. L. F. , Gomes Pedro H. , Ueyama Jó
Published: February 2016

Brazil is an agricultural nation whose process of spraying pesticides is mainly carried out by using aircrafts. However, the use of aircrafts with on-board pilots has often resulted in chemicals being sprayed outside the intended areas. The precision required for spraying on crop fields is often impaired by external factors, like changes in wind speed and direction. To address this problem, ensuring that the pesticides are sprayed accurately, this paper proposes the use of artificial neural networks (ANN) on programmable UAVs. For such, the UAV is programmed to spray chemicals on the target crop field considering dynamic context. To control the UAV ight route planning, we investigated several optimization techniques including Particle Swarm Optimization (PSO). We employ PSO to find near-optimal parameters for static environments and then train a neural network to interpolate PSO solutions in order to improve the UAV route in dynamic environments. Experimental results showed a gain in the spraying precision in dynamic environments when ANN and PSO were combined. We demonstrate the improvement in figures when compared against the exclusive use of PSO. This approach will be embedded in UAVs with programmable boards, such as Raspberry PIs or Beaglebones. The experimental results demonstrate that the proposed approach is feasible and can meet the demand for a fast response time needed by the UAV to adjust its route in a highly dynamic environment, while seeking to spray pesticides accurately.
Branching Optimization for Transporting Tasks in the Plane
Authors: Piersa Jaroslaw
Published: February 2016

In this work we propose a simulated annealing based search algorithm for optimal ramified or branched transportation route in [Formula: see text]. The cost function of the transport network allows the system to merge small roads into larger highways, carry the goods together and separate them near the destination. As a result the transportation route has multiple branching-in and -out points, to some extent similar to nerve system of the tree leaf. The problem is known to be NP-complete even for finite set of branching points and metric spaces.
A Versatile Multi-Agent Traffic Simulator Framework Based on Real Data
Authors: Bonhomme Alexandre , Mathieu Philippe , Picault Sébastien
Published: February 2016

Among real-system applications of AI, the field of traffic simulation makes use of a wide range of techniques and algorithms. Especially, microscopic models of road traffic have been expanding for several years. Indeed, Multi-Agent Systems provide the capability of modeling the very diversity of individual behaviors. Several professional tools provide comprehensive sets of ready-made, accurate behaviors for several kinds of vehicles. The price in such tools is the difficulty to modify the nature of programmed behaviors, and the specialization in a single purpose, e.g. either studying resulting ows, or providing an immersive virtual reality environment. Thus, we advocate for a more exible approach for the design of multi-purpose tools for decision support. Especially, the use of geographical open databases offers the opportunity to design agent-based traffic simulators which can be continuously informed of changes in traffic conditions. Our proposal also makes decision support systems able to integrate environmental and behavioral modifications in a linear fashion, and to compare various scenarios built from different hypotheses in terms of actors, behaviors, environment and ows. We also describe here the prototype tool that has been implemented according to our design principles.
The role of Lagrange multiplier in Gauss–Bonnet dark energy
Authors: Makarenko Andrey N.
Published: February 2016

We review accelerating cosmology in Gauss–Bonnet gravity with Lagrange multiplier constraint studied in [S. Capozziello, A. N. Makarenko and S. D. Odintsov, Phys. Rev. D 87 (2013) 084037, arXiv: 1302.0093 [gr-qc], S. Capozziello, M. Francaviglia and A. N. Makarenko, Astrophys. Space Sci. 349 (2014) 603–609, arXiv: 1304.5440 [gr-qc]. Several examples of dark energy universes are presented. We can get new dark energy solutions (with additional scalar) as well as certain limits to earlier found accelerating solutions.
An upper bound on the growth of Dirichlet tilings of hyperbolic spaces
Authors: Benjamini Itai , Gelander Tsachik
Published: February 2016

It is shown that the growth rate [Formula: see text] of any [Formula: see text] faces Dirichlet tiling of [Formula: see text] is at most [Formula: see text], for an [Formula: see text], depending only on [Formula: see text] and [Formula: see text]. We do not know if there is a universal [Formula: see text], such that [Formula: see text] upperbounds the growth rate for any [Formula: see text]-regular tiling, when [Formula: see text]?
A new approach for detecting sudden hypotension in hemodialysis by using dual-channel optical system
Authors: Mohamad Amin Younessi Heravi , Ebrahim Golmakani , Sima Joharinia
Published: February 2016

Dialysis hypotension is one of the most prevalence symptoms of dialysis and occurs in 40% of treatment sessions. Detection and prediction of hypotension is important for the well-being of the patient and for optimizing treatment. The aim of this study was to construct optical system to monitor blood pressure (BP) continuously and without cuff in hemodialysis based on pulse transit time (PTT) method. To measure the BP changes, dual-channel optical system were developed. In this study, individuals were classified into two groups of normal and hemodialysis. In both groups, BP and consequently PTT were earned three times in different positions. After the initial calibration, the regression equation was drawn for each subject. In normal group, each subject was placed in the supine position and BP was measured both by designed system and sphygmomanometer cuff. During BP measurements, in addition to BP, blood pressure decline was also monitored by optical system. For hemodialysis group, the same measurement setup was adopted. In both groups, the error between cuff method and PTT was calculated. Correlation coefficients for BPcuff vs BPPTT were calculated and Bland–Altman plot was performed for the normal and hemodialysis groups. In this study 16 subjects participated. The results for normal group showed that maximum difference between cuff method and the present method was 14[Formula: see text]mmHg and for dialysis group was 16[Formula: see text]mmHg. Bland–Altman plot in normal group revealed limits of agreement from [Formula: see text]13.98 to 13.18[Formula: see text]mmHg. Considering hemodialysis group, limits of agreement were from [Formula: see text]15.94 to 13.88[Formula: see text]mmHg. The correlation coefficient was 0.74 for normal group and was 0.72 for hemodialysis group. The proposed system can monitor BP continuously and diagnose sudden hypotension. So it can be recommended as a useful method to indicate hypotension and can be used for dialysis unit.
Modeling method for integration of air command and security process
Authors: Luo Yongliang , Wu Yingnian , Qin Yuanhui , Zhang Lin , Wang Yuanming
Published: February 2016

Air command and security (ACS) process is a kind of typical complex operation process. Its modeling issue has become a hot spot and challenge in the research field of complex operation process. Combining the demand on the application of air command and support, this paper proposes a simulation-based modeling method of integrating air command and support process, emphatically describing such aspects as the meta-model of the concept of aviation support process, work flow service modeling and arrangement of multi-aircraft process, etc. Finally, based on actual cases of application, this paper unfolds simulating verification and assessment on the whole process of control and support operation process of a flight task involving multiple aircrafts.
The Role of Cores in Recommender Benchmarking for Social Bookmarking Systems
Authors: Doerfel Stephan , Jäschke Robert , Stumme Gerd
Published: February 2016

Social bookmarking systems have established themselves as an important part in today’s Web. In such systems,
tag recommender systems
support users during the posting of a resource by suggesting suitable tags. Tag recommender algorithms have often been evaluated in offline benchmarking experiments. Yet, the particular setup of such experiments has rarely been analyzed. In particular, since the recommendation quality usually suffers from difficulties such as the sparsity of the data or the cold-start problem for new resources or users, datasets have often been pruned to so-called
cores
(specific subsets of the original datasets), without much consideration of the implications on the benchmarking results.

In this article, we generalize the notion of a core by introducing the new notion of a
set-core
, which is independent of any graph structure, to overcome a structural drawback in the previous constructions of cores on tagging data. We show that problems caused by some types of cores can be eliminated using set-cores. Further, we present a thorough analysis of tag recommender benchmarking setups using cores. To that end, we conduct a large-scale experiment on four real-world datasets, in which we analyze the influence of different cores on the evaluation of recommendation algorithms. We can show that the results of the comparison of different recommendation approaches depends on the selection of core type and level. For the benchmarking of tag recommender algorithms, our results suggest that the evaluation must be set up more carefully and should not be based on one arbitrarily chosen core type and level.
Recompression
Authors: Jeż Artur
Published: February 2016

In this article, we present an application of a simple technique of local recompression, previously developed by the author in the context algorithms for compressed strings [Jeż 2014a, 2015b, 2015a], to word equations. The technique is based on local modification of variables (replacing
X
by
aX
or
Xa
) and iterative replacement of pairs of letters occurring in the equation by a “fresh” letter, which can be seen as a bottom-up
compression
of the solution of the given word equation, or, to be more specific, building a Straight-Line Programme for the solution of the word equation.

Using this technique, we give new, independent, and self-contained proofs of many known results for word equations. To be more specific, the presented (nondeterministic) algorithm runs in
O
(
n
log
n
space and in time polynomial in
n
and log
N
, where
n
is the size of the input equation and
N
the size of the length-minimal solution of the word equation. Furthermore, for
O
(1) variables, the bound on the space consumption is in fact linear, that is,
O
(
m
), where
m
is the size of the space used by the input. This yields that for each
k
the set of satisfiable word equations with
k
variables is context sensitive. The presented algorithm can be easily generalised to a generator of all solutions of the given word equation (without increasing the space usage). Furthermore, a further analysis of the algorithm yields an independent proof of doubly exponential upper bound on the size of the length-minimal solution. The presented algorithm does not use exponential bound on the exponent of periodicity. Conversely, the analysis of the algorithm yields an independent proof of the exponential bound on exponent of periodicity.
Efficient Dynamic Provable Possession of Remote Data via Update Trees
Authors: Zhang Yihua , Blanton Marina
Published: February 2016

The emergence and wide availability of remote storage service providers prompted work in the security community that allows clients to verify integrity and availability of the data that they outsourced to a not fully trusted remote storage server at a relatively low cost. Most recent solutions to this problem allow clients to read and update (i.e., insert, modify, or delete) stored data blocks while trying to lower the overhead associated with verifying the integrity of the stored data. In this work, we develop a novel scheme, performance of which favorably compares with the existing solutions. Our solution additionally enjoys a number of new features, such as a natural support for operations on ranges of blocks, revision control, and support for multiple user access to shared content. The performance guarantees that we achieve stem from a novel data structure called a
balanced update tree
and removing the need for interaction during update operations in addition to communicating the updates themselves.
A Method to Analyze Computer Science Students’ Teamwork in Online Collaborative Learning Environments
Authors: Vivian Rebecca , Falkner Katrina , Falkner Nickolas , Tarmazdi Hamid
Published: February 2016

Although teamwork has been identified as an essential skill for Computer Science (CS) graduates, these skills are identified as lacking by industry employers, which suggests a need for more proactive measures to teach and assess teamwork. In one CS course, students worked in teams to create a wiki solution to problem-based questions. Through a case-study approach, we test a developed teamwork framework, using manual content analysis and sentiment analysis, to determine if the framework can provide insight into students’ teamwork behavior and to determine if the wiki task encouraged students to collaborate, share knowledge, and self-adopt teamwork roles. Analysis revealed the identification of both active and cohesive teams, disengaged students, and particular roles and behaviors that were lacking. Furthermore, sentiment analysis revealed that teams moved through positive and negative emotions over the course of developing their solution, toward satisfaction. The findings demonstrate the value of the detailed analysis of online teamwork. However, we propose the need for automated measures that provide real-time feedback to assist educators in the fair and efficient assessment of teamwork. We present a prototype system and recommendations, based on our analysis, for automated teamwork analysis tools.
Preaveraging and Carry Propagate Approaches to Side-Channel Analysis of HMAC-SHA256
Authors: Gebotys Catherine H. , White Brian A. , Mateos Edgar
Published: February 2016

Although HMAC-SHA has been standardized for over a decade, few published attacks on the single-cycle round implementation exist. In this research, new attack techniques are provided, for the first time, (1) to help to discriminate between values of secret intermediate variables within HMAC and (2) to reduce the large word size complexity. Preaveraging and carry propagate techniques are proposed using chosen plaintexts and shown to significantly reduce the complexity and runtimes for side-channel analysis of an Altera FPGA platform. This research is important for advancing side channel analysis of complex embedded ASICs and ensuring secure implementations in future embedded ubiquitous devices.
Algebraic Structures for Capturing the Provenance of SPARQL Queries
Authors: Geerts Floris , Unger Thomas , Karvounarakis Grigoris , Fundulaki Irini , Christophides Vassilis
Published: February 2016

The evaluation of SPARQL algebra queries on various kinds of annotated RDF graphs can be seen as a particular case of the evaluation of these queries on RDF graphs annotated with elements of so-called
spm-semirings
. Spm-semirings extend semirings, used for representing the provenance of positive relational algebra queries on annotated relational data, with a new operator to capture the semantics of the non-monotone SPARQL operators. Furthermore, spm-semiring-based annotations ensure that desired SPARQL query equivalences hold when querying annotated RDF. In this work, in addition to introducing spm-semirings, we study their properties and provide an alternative characterization of these structures in terms of semirings with an embedded boolean algebra (or seba-structure for short). This characterization allows us to construct spm-semirings and identify a universal object in the class of spm-semirings. Finally, we show that this universal object provides a provenance representation of poly-sized overhead and can be used to evaluate SPARQL queries on arbitrary spm-semiring-annotated RDF graphs.
Safeguarding and Accessing Drama as Intangible Cultural Heritage
Authors: Lombardo Vincenzo , Pizzo Antonio , Damiano Rossana
Published: February 2016

Storytelling, especially in the form called drama, is pervasive across cultures and ages. Though much attention has been devoted to the preservation of the physical supports of drama (e.g., films and tapes), there is a widespread acknowledgment that such tangible heritage is the expression of an intangible notion of drama. This article introduces drama as a form of intangible cultural heritage and presents a solution for its preservation in terms of a formal encoding through a computational ontology.

After the review of a formal representation of drama, called Drammar, developed in previous works, we show how an abstraction of drama can be encoded into a digital item. We also show how the method proposed is compliant with the major initiatives for the documentation of cultural heritage, namely CIDOC-CRM and FRBR. Finally, we test the applicability of our solution by showing how the major tenets of two well-known theories of drama can be encoded in Drammar and presenting the results of a focus group of drama scholars and practitioners who have accessed the encoding through a visualization system. The encoding and visualization system have turned out to be a promising support for teaching and investigating drama.
Power Law Distributions in Information Retrieval
Authors: Petersen Casper , Simonsen Jakob Grue , Lioma Christina
Published: February 2016

Several properties of information retrieval (IR) data, such as query frequency or document length, are widely considered to be approximately distributed as a power law. This common assumption aims to focus on specific characteristics of the empirical probability distribution of such data (e.g., its scale-free nature or its long/fat tail). This assumption, however, may not be always true. Motivated by recent work in the statistical treatment of power law claims, we investigate two research questions: (i) To what extent do power law approximations hold for term frequency, document length, query frequency, query length, citation frequency, and syntactic unigram frequency? And (ii) what is the computational cost of replacing ad hoc power law approximations with more accurate distribution fitting? We study 23 TREC and 5 non-TREC datasets and compare the fit of power laws to 15 other standard probability distributions. We find that query frequency and 5 out of 24 term frequency distributions are best approximated by a power law. All remaining properties are better approximated by the Inverse Gaussian, Generalized Extreme Value, Negative Binomial, or Yule distribution. We also find the overhead of replacing power law approximations by more informed distribution fitting to be negligible, with potential gains to IR tasks like index compression or test collection generation for IR evaluation.
Enhancing Shift-Reduce Constituent Parsing with Action N-Gram Model
Authors: Zhou Hao , Huang Shujian , Zhou Junsheng , Zhang Yue , Chen Huadong , Dai Xinyu , Cheng Chuan , Chen Jiajun
Published: February 2016

Current shift-reduce parsers “understand” the context by embodying a large number of binary indicator features with a discriminative model. In this article, we propose the action n-gram model, which utilizes the action sequence to help parsing disambiguation. The action n-gram model is trained on action sequences produced by parsers with the n-gram estimation method, which gives a smoothed maximum likelihood estimation of the action probability given a specific action history. We show that incorporating action n-gram models into a state-of-the-art parsing framework could achieve parsing accuracy improvements on three datasets across two languages.
Internet of Things in Energy Efficiency
Authors: Jammes Francois
Published: February 2016

This paper aims to provide the view of what means IoT (Internet of Things) in energy efficiency applications, of its technical and business impacts, of its opportunities and risks for the different market players. It is concluded by the author's long term vision about the use of IoT in energy efficiency applications.
Volunteerism Tendency Prediction via Harvesting Multiple Social Networks
Authors: Song Xuemeng , Ming Zhao-Yan , Nie Liqiang , Zhao Yi-Liang , Chua Tat-Seng
Published: February 2016

Volunteers have always been extremely crucial and in urgent need for nonprofit organizations (NPOs) to sustain their continuing operations. However, it is expensive and time-consuming to recruit volunteers using traditional approaches. In the Web 2.0 era, abundant and ubiquitous social media data opens a door to the possibility of automatic volunteer identification. In this article, we aim to fully explore this possibility by proposing a scheme that is able to predict users’ volunteerism tendency from user-generated contents collected from multiple social networks based on a conceptual volunteering decision model. We conducted comprehensive experiments to investigate the effectiveness of our proposed scheme and further discussed its generalizibility and extendability. This novel interdisciplinary research will potentially inspire more promising and important human-centered applications.
Physiopucks
Authors: Cincuegrani S. Mealla , Jordà S. , Väljamäe A.
Published: February 2016

In this article, we evaluateb-Reactable, a digital music instrument that combines implicit physiology-based interaction through EEG and ECG, and explicit gestural interaction for sound generation and control. This multimodality is embodied in tangible objects namedphysiopucks,which are driven by biosignals. We hypothesize that multimodality increases users’ motivation in a musical task, compared to the use of a gesture-only tabletop system (the Reactable). We compared motivational aspects in dyads collaborating in three experimental groups (N = 56): the Physio group (one physiology- and one gesture-based user), the Sham group (one prerecorded physiology- and one gesture-based user), and the Control group (two gesture users). Between-group comparisons showed that motivation dimensions of Confidence and Satisfaction were higher inb-Reactablethan in the gesture-only tangible interface, and that fake physiology-based feedback significantly reduced these effects. Our study also shows the potential of combined implicit and explicit interaction modes in multiuser HCI scenarios.
Interactively Cutting and Constraining Vertices in Meshes Using Augmented Matrices
Authors: Yeung Yu-Hong , Crouch Jessica , Pothen Alex
Published: February 2016

We present a finite-element solution method that is well suited for interactive simulations of cutting meshes in the regime of linear elastic models. Our approach features fast updates to the solution of the stiffness system of equations to account for real-time changes in mesh connectivity and boundary conditions. Updates are accomplished by augmenting the stiffness matrix to keep it consistent with changes to the underlying model, without refactoring the matrix at each step of cutting. The initial stiffness matrix and its Cholesky factors are used to implicitly form and solve a Schur complement system using an iterative solver. As changes accumulate over many simulation timesteps, the augmented solution method slows down due to the size of the augmented matrix. However, by periodically refactoring the stiffness matrix in a concurrent background process, fresh Cholesky factors that incorporate recent model changes can replace the initial factors. This controls the size of the augmented matrices and provides a way to maintain a fast solution rate as the number of changes to a model grows. We exploit sparsity in the stiffness matrix, the right-hand-side vectors and the solution vectors to compute the solutions fast, and show that the time complexity of the update steps is bounded linearly by the size of the Cholesky factor of the initial matrix. Our complexity analysis and experimental results demonstrate that this approach scales well with problem size. Results for cutting and deformation of 3D linear elastic models are reported for meshes representing the brain, eye, and model problems with element counts up to 167,000; these show the potential of this method for real-time interactivity. An application to limbal incisions for surgical correction of astigmatism, for which linear elastic models and small deformations are sufficient, is included.
Actor-Critic Algorithms with Online Feature Adaptation
Authors: Prabuchandran K. J. , Bhatnagar Shalabh , Borkar Vivek S.
Published: February 2016

We develop two new online actor-critic control algorithms with adaptive feature tuning for Markov Decision Processes (MDPs). One of our algorithms is proposed for the long-run average cost objective, while the other works for discounted cost MDPs. Our actor-critic architecture incorporates parameterization both in the policy and the value function. A gradient search in the policy parameters is performed to improve the performance of the actor. The computation of the aforementioned gradient, however, requires an estimate of the value function of the policy corresponding to the current actor parameter. The value function, on the other hand, is approximated using linear function approximation and obtained from the critic. The error in approximation of the value function, however, results in suboptimal policies. In our article, we also update the features by performing a gradient descent on the Grassmannian of features to minimize a mean square Bellman error objective in order to find the best features. The aim is to obtain a good approximation of the value function and thereby ensure convergence of the actor to locally optimal policies. In order to estimate the gradient of the objective in the case of the average cost criterion, we utilize the policy gradient theorem, while in the case of the discounted cost objective, we utilize the simultaneous perturbation stochastic approximation (SPSA) scheme. We prove that our actor-critic algorithms converge to locally optimal policies. Experiments on two different settings show performance improvements resulting from our feature adaptation scheme.
Audio Surveillance
Authors: Crocco Marco , Cristani Marco , Trucco Andrea , Murino Vittorio
Published: February 2016

Despite surveillance systems becoming increasingly ubiquitous in our living environment, automated surveillance, currently based on video sensory modality and machine intelligence, lacks most of the time the robustness and reliability required in several real applications. To tackle this issue, audio sensory devices have been incorporated, both alone or in combination with video, giving birth in the past decade, to a considerable amount of research. In this article, audio-based automated surveillance methods are organized into a comprehensive survey: A general taxonomy, inspired by the more widespread video surveillance field, is proposed to systematically describe the methods covering background subtraction, event classification, object tracking, and situation analysis. For each of these tasks, all the significant works are reviewed, detailing their pros and cons and the context for which they have been proposed. Moreover, a specific section is devoted to audio features, discussing their expressiveness and their employment in the above-described tasks. Differing from other surveys on audio processing and analysis, the present one is specifically targeted to automated surveillance, highlighting the target applications of each described method and providing the reader with a systematic and schematic view useful for retrieving the most suited algorithms for each specific requirement.
Keeping TOCE on a Positive Trajectory
Authors: Hundhausen Christopher D.
Published: February 2016

In my inaugural editorial as the new editor-in-chief of the
ACM Transactions on Computing Education
, I take stock of the journal's progress in its first 6 years of existence, and I describe my plans to help the journal maintain its positive trajectory as a viable and vibrant computing education research journal.
Convolution as a Unifying Concept
Authors: Dongol Brijesh , Hayes Ian J. , Struth Georg
Published: February 2016

A notion of convolution is presented in the context of formal power series together with lifting constructions characterising algebras of such series, which usually are quantales. A number of examples underpin the universality of these constructions, the most prominent ones being separation logics, where convolution is separating conjunction in an assertion quantale; interval logics, where convolution is the chop operation; and stream interval functions, where convolution is proposed for analysing the trajectories of dynamical or real-time systems. A Hoare logic can be constructed in a generic fashion on the power-series quantale, which applies to each of these examples. In many cases, commutative notions of convolution have natural interpretations as concurrency operations.
A Large-Deviation-Based Splitting Estimation of Power Flow Reliability
Authors: Wadman Wander S. , Crommelin Daan T. , Zwart Bert P.
Published: February 2016

Given the continued integration of intermittent renewable generators in electrical power grids, connection overloads are of increasing concern for grid operators. The risk of an overload due to injection variability can be described mathematically as a barrier-crossing probability of a function of a multidimensional stochastic process. Crude Monte Carlo is a well-known technique to estimate probabilities, but it may be computationally too intensive in this case as typical modern power grids rarely exhibit connection overloads. In this article, we derive an approximate rate function for the overload probability using results from large deviations theory. Based on this large deviations approximation, we apply a rare event simulation technique called splitting to estimate overload probabilities more efficiently than Crude Monte Carlo simulation.

We show on example power grids with up to 11 stochastic power injections that for a fixed accuracy, Crude Monte Carlo would require tens to millions as many samples as the proposed splitting technique required. We investigate the balance between accuracy and workload of three splitting schemes, each based on a different approximation of the rate function. We justify the workload increase of large-deviation-based splitting compared to naive splitting—that is, splitting based on merely the Euclidean distance to the rare event set. For a fixed accuracy, naive splitting requires over 60 times as much CPU time as large-deviation-based splitting, illustrating its computational advantage. In these examples, naive splitting—unlike large-deviation-based splitting—requires even more CPU time than CMC simulation, illustrating its pitfall.
Monitoring Bats in the Wild
Authors: Dressler Falko , Mutschlechner Margit , Li Bijun , Kapitza Rüdiger , Ripperger Simon , Eibel Christopher , Herzog Benedict , Hönig Timo , Schröder-Preikschat Wolfgang
Published: February 2016

We explore the advantages of using Erasure Codes (ECs) in a very challenging sensor networking scenario, namely, monitoring and tracking bats in the wild. The mobile bat nodes collect contact information that needs to be transmitted to stationary base stations whenever they are in communication range. We are particularly interested in improving the overall communication reliability of the wireless communication. The mobile nodes are capable of storing a few 100kB of data and to exchange contact information in aggregated form. Due to the continuous flight of the bats and the forest environment, the wireless channel quality varies quickly and, thus, the communication is in general assumed to be highly unreliable. Given the very strict energy constraints of the mobile node and the inherently asymmetric channels, conventional techniques such as full data replication or Automatic Repeat Request to improve the communication reliability are prohibitive. In this work, we investigate the tradeoff between reliability achieved and the cost in form of additional transmissions, that is, the additional energy costs. Our energy measurements on a real platform combined with larger-scale simulation of the wireless communication clearly indicate the advantages of using ECs in our scenario. The results are also applicable in other configurations when unreliable communication channels meet tight energy budgets.
What is new in CoCoALib and CoCoA-5?
Authors: Abbott John , Bigatti Anna Maria
Published: February 2016

CoCoA is a well-established Computer Algebra System for Computations in Commutative Algebra, and specifically for Gröbner bases. In the last few years the CoCoA software has undergone a profound change: the code has been totally re-written in C++, and includes CoCoA-5 (an interactive system) and CoCoALib (an open source C++ library).

The new CoCoA-5 language resembles the old CoCoA-4 language, but has clearly defined semantics, making it both more robust and more flexible than CoCoA-4.

CoCoALib is the mathematical core; its design focusses on ease of use so that other software can readily use it as a library for multivariate polynomial computations and other Commutative Algebra operations.

The internal design of the software makes it easy to integrate other libraries and to render all CoCoALib extensions accessible via the interactive CoCoA-5 system.
Computation tool for theq-deformed quasi-shuffle algebras and representations of structure of MZVs
Authors: Van Chien Bui , Duchamp G. H. E. , Minh Hoang Ngoc
Published: February 2016

We would like to introduce our package using Maple to compute within theq-deformed1quasi-shuffle algebras and to represent structure of multiple zeta values (MZVs). For this package, we can define an arbitrary alphabet from which the letters associated with indices totally ordered and then carry out computations on words, that will complement functions for the packageStringToolsin Maple. In the vector space of (noncommutative) polynomials which is equippedq-deformed quasi-shuffle products and concatenation product [1, 2], we compute the bases in duality and express an arbitrary homogeneous polynomial in terms of these bases. Moreover, due to our algorithms, we can represent structure of MZVs on the transcendence bases in terms of irreducible elements [4]. We used this package to compute all examples and verify the results in the paper [4] which was present at the conference ISSAC 2015.
Lacunaryx
Authors: Grenet Bruno
Published: February 2016

In this paper, we report on an implementation in the free software Mathemagix[9] of lacunary factorization algorithms, distributed as a library called Lacunaryx. These algorithms take as input a polynomial in sparse representation, that is as a list of nonzero monomials, and an integerd, and compute its degree-dfactors.2The complexity of these algorithms is polynomial in thesparse sizeof the input polynomial andd: The sparse size of a polynomial [EQUATION] logwhere theh(·) denotes theheightof a rational number, that is the maximum of the absolute values of its numerator and denominator.
Polynomial homotopy continuation on GPUs
Authors: Verschelde Jan , Yu Xiangcheng
Published: February 2016

The purpose of the software presentation is to announce a library to track many solution paths defined by a polynomial homotopy on a Graphics Processing Unit (GPU). Developed on NVIDIA graphics cards with CUDA SDKs, our code is released under the GNU GPL license. Via the C interface to PHCpack, we can call our GPU library from Python.