14 research outputs found
CP-SLAM: Collaborative Neural Point-based SLAM System
This paper presents a collaborative implicit neural simultaneous localization
and mapping (SLAM) system with RGB-D image sequences, which consists of
complete front-end and back-end modules including odometry, loop detection,
sub-map fusion, and global refinement. In order to enable all these modules in
a unified framework, we propose a novel neural point based 3D scene
representation in which each point maintains a learnable neural feature for
scene encoding and is associated with a certain keyframe. Moreover, a
distributed-to-centralized learning strategy is proposed for the collaborative
implicit SLAM to improve consistency and cooperation. A novel global
optimization framework is also proposed to improve the system accuracy like
traditional bundle adjustment. Experiments on various datasets demonstrate the
superiority of the proposed method in both camera tracking and mapping.Comment: Accepted at NeurIPS 202
Opinion Mining for Software Development: A Systematic Literature Review
Opinion mining, sometimes referred to as sentiment analysis, has gained increasing attention in software engineering (SE) studies.
SE researchers have applied opinion mining techniques in various contexts, such as identifying developers’ emotions expressed in
code comments and extracting users’ critics toward mobile apps. Given the large amount of relevant studies available, it can take
considerable time for researchers and developers to figure out which approaches they can adopt in their own studies and what perils
these approaches entail.
We conducted a systematic literature review involving 185 papers. More specifically, we present 1) well-defined categories of opinion
mining-related software development activities, 2) available opinion mining approaches, whether they are evaluated when adopted in
other studies, and how their performance is compared, 3) available datasets for performance evaluation and tool customization, and 4)
concerns or limitations SE researchers might need to take into account when applying/customizing these opinion mining techniques.
The results of our study serve as references to choose suitable opinion mining tools for software development activities, and provide
critical insights for the further development of opinion mining techniques in the SE domain
A Survey of Practical Formal Methods for Security
In today's world, critical infrastructure is often controlled by computing systems. This introduces new risks for cyber attacks, which can compromise the security and disrupt the functionality of these systems. It is therefore necessary to build such systems with strong guarantees of resiliency against cyber attacks. One way to achieve this level of assurance is using formal verification, which provides proofs of system compliance with desired cyber security properties. The use of Formal Methods (FM) in aspects of cyber security and safety-critical systems are reviewed in this article. We split FM into the three main classes: theorem proving, model checking, and lightweight FM. To allow the different uses of FM to be compared, we define a common set of terms. We further develop categories based on the type of computing system FM are applied in. Solutions in each class and category are presented, discussed, compared, and summarised. We describe historical highlights and developments and present a state-of-the-art review in the area of FM in cyber security. This review is presented from the point of view of FM practitioners and researchers, commenting on the trends in each of the classes and categories. This is achieved by considering all types of FM, several types of security and safety-critical systems, and by structuring the taxonomy accordingly. The article hence provides a comprehensive overview of FM and techniques available to system designers of security-critical systems, simplifying the process of choosing the right tool for the task. The article concludes by summarising the discussion of the review, focusing on best practices, challenges, general future trends, and directions of research within this field
Big Data and Large-scale Data Analytics: Efficiency of Sustainable Scalability and Security of Centralized Clouds and Edge Deployment Architectures
One of the significant shifts of the next-generation computing technologies will certainly be in
the development of Big Data (BD) deployment architectures. Apache Hadoop, the BD
landmark, evolved as a widely deployed BD operating system. Its new features include
federation structure and many associated frameworks, which provide Hadoop 3.x with the
maturity to serve different markets. This dissertation addresses two leading issues involved in
exploiting BD and large-scale data analytics realm using the Hadoop platform. Namely,
(i)Scalability that directly affects the system performance and overall throughput using
portable Docker containers. (ii) Security that spread the adoption of data protection practices
among practitioners using access controls. An Enhanced Mapreduce Environment (EME),
OPportunistic and Elastic Resource Allocation (OPERA) scheduler, BD Federation Access Broker
(BDFAB), and a Secure Intelligent Transportation System (SITS) of multi-tiers architecture for
data streaming to the cloud computing are the main contribution of this thesis study
Making Presentation Math Computable
This Open-Access-book addresses the issue of translating mathematical expressions from LaTeX to the syntax of Computer Algebra Systems (CAS). Over the past decades, especially in the domain of Sciences, Technology, Engineering, and Mathematics (STEM), LaTeX has become the de-facto standard to typeset mathematical formulae in publications. Since scientists are generally required to publish their work, LaTeX has become an integral part of today's publishing workflow. On the other hand, modern research increasingly relies on CAS to simplify, manipulate, compute, and visualize mathematics. However, existing LaTeX import functions in CAS are limited to simple arithmetic expressions and are, therefore, insufficient for most use cases. Consequently, the workflow of experimenting and publishing in the Sciences often includes time-consuming and error-prone manual conversions between presentational LaTeX and computational CAS formats. To address the lack of a reliable and comprehensive translation tool between LaTeX and CAS, this thesis makes the following three contributions. First, it provides an approach to semantically enhance LaTeX expressions with sufficient semantic information for translations into CAS syntaxes. Second, it demonstrates the first context-aware LaTeX to CAS translation framework LaCASt. Third, the thesis provides a novel approach to evaluate the performance for LaTeX to CAS translations on large-scaled datasets with an automatic verification of equations in digital mathematical libraries. This is an open access book
Making Presentation Math Computable
This Open-Access-book addresses the issue of translating mathematical expressions from LaTeX to the syntax of Computer Algebra Systems (CAS). Over the past decades, especially in the domain of Sciences, Technology, Engineering, and Mathematics (STEM), LaTeX has become the de-facto standard to typeset mathematical formulae in publications. Since scientists are generally required to publish their work, LaTeX has become an integral part of today's publishing workflow. On the other hand, modern research increasingly relies on CAS to simplify, manipulate, compute, and visualize mathematics. However, existing LaTeX import functions in CAS are limited to simple arithmetic expressions and are, therefore, insufficient for most use cases. Consequently, the workflow of experimenting and publishing in the Sciences often includes time-consuming and error-prone manual conversions between presentational LaTeX and computational CAS formats. To address the lack of a reliable and comprehensive translation tool between LaTeX and CAS, this thesis makes the following three contributions. First, it provides an approach to semantically enhance LaTeX expressions with sufficient semantic information for translations into CAS syntaxes. Second, it demonstrates the first context-aware LaTeX to CAS translation framework LaCASt. Third, the thesis provides a novel approach to evaluate the performance for LaTeX to CAS translations on large-scaled datasets with an automatic verification of equations in digital mathematical libraries. This is an open access book
Exploring attributes, sequences, and time in Recommender Systems: From classical to Point-of-Interest recommendation
Tesis Doctoral inĂ©dita leĂda en la Universidad AutĂłnoma de Madrid, Escuela PolitĂ©cnica Superior, Departamento de Ingenieria Informática. Fecha de lectura: 08-07-2021Since the emergence of the Internet and the spread of digital communications
throughout the world, the amount of data stored on the Web has been
growing exponentially. In this new digital era, a large number of companies
have emerged with the purpose of ltering the information available on the
web and provide users with interesting items. The algorithms and models
used to recommend these items are called Recommender Systems. These
systems are applied to a large number of domains, from music, books, or
movies to dating or Point-of-Interest (POI), which is an increasingly popular
domain where users receive recommendations of di erent places when
they arrive to a city.
In this thesis, we focus on exploiting the use of contextual information, especially
temporal and sequential data, and apply it in novel ways in both
traditional and Point-of-Interest recommendation. We believe that this type
of information can be used not only for creating new recommendation models
but also for developing new metrics for analyzing the quality of these
recommendations. In one of our rst contributions we propose di erent
metrics, some of them derived from previously existing frameworks, using
this contextual information. Besides, we also propose an intuitive algorithm
that is able to provide recommendations to a target user by exploiting the
last common interactions with other similar users of the system.
At the same time, we conduct a comprehensive review of the algorithms
that have been proposed in the area of POI recommendation between 2011
and 2019, identifying the common characteristics and methodologies used.
Once this classi cation of the algorithms proposed to date is completed, we
design a mechanism to recommend complete routes (not only independent
POIs) to users, making use of reranking techniques. In addition, due to the
great di culty of making recommendations in the POI domain, we propose
the use of data aggregation techniques to use information from di erent
cities to generate POI recommendations in a given target city.
In the experimental work we present our approaches on di erent datasets
belonging to both classical and POI recommendation. The results obtained
in these experiments con rm the usefulness of our recommendation proposals,
in terms of ranking accuracy and other dimensions like novelty, diversity,
and coverage, and the appropriateness of our metrics for analyzing temporal
information and biases in the recommendations producedDesde la aparici on de Internet y la difusi on de las redes de comunicaciones
en todo el mundo, la cantidad de datos almacenados en la red ha crecido
exponencialmente. En esta nueva era digital, han surgido un gran n umero
de empresas con el objetivo de ltrar la informaci on disponible en la red
y ofrecer a los usuarios art culos interesantes. Los algoritmos y modelos
utilizados para recomendar estos art culos reciben el nombre de Sistemas de
Recomendaci on. Estos sistemas se aplican a un gran n umero de dominios,
desde m usica, libros o pel culas hasta las citas o los Puntos de Inter es (POIs,
en ingl es), un dominio cada vez m as popular en el que los usuarios reciben
recomendaciones de diferentes lugares cuando llegan a una ciudad.
En esta tesis, nos centramos en explotar el uso de la informaci on contextual,
especialmente los datos temporales y secuenciales, y aplicarla de forma novedosa
tanto en la recomendaci on cl asica como en la recomendaci on de POIs.
Creemos que este tipo de informaci on puede utilizarse no s olo para crear
nuevos modelos de recomendaci on, sino tambi en para desarrollar nuevas
m etricas para analizar la calidad de estas recomendaciones. En una de
nuestras primeras contribuciones proponemos diferentes m etricas, algunas
derivadas de formulaciones previamente existentes, utilizando esta informaci
on contextual. Adem as, proponemos un algoritmo intuitivo que es
capaz de proporcionar recomendaciones a un usuario objetivo explotando
las ultimas interacciones comunes con otros usuarios similares del sistema.
Al mismo tiempo, realizamos una revisi on exhaustiva de los algoritmos que
se han propuesto en el a mbito de la recomendaci o n de POIs entre 2011 y
2019, identi cando las caracter sticas comunes y las metodolog as utilizadas.
Una vez realizada esta clasi caci on de los algoritmos propuestos hasta la
fecha, dise~namos un mecanismo para recomendar rutas completas (no s olo
POIs independientes) a los usuarios, haciendo uso de t ecnicas de reranking.
Adem as, debido a la gran di cultad de realizar recomendaciones en el
ambito de los POIs, proponemos el uso de t ecnicas de agregaci on de datos
para utilizar la informaci on de diferentes ciudades y generar recomendaciones
de POIs en una determinada ciudad objetivo.
En el trabajo experimental presentamos nuestros m etodos en diferentes
conjuntos de datos tanto de recomendaci on cl asica como de POIs. Los
resultados obtenidos en estos experimentos con rman la utilidad de nuestras
propuestas de recomendaci on en t erminos de precisi on de ranking y de
otras dimensiones como la novedad, la diversidad y la cobertura, y c omo de
apropiadas son nuestras m etricas para analizar la informaci on temporal y
los sesgos en las recomendaciones producida
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Building information modeling – A game changer for interoperability and a chance for digital preservation of architectural data?
Digital data associated with the architectural design-andconstruction
process is an essential resource alongside -and even
past- the lifecycle of the construction object it describes. Despite
this, digital architectural data remains to be largely neglected in
digital preservation research – and vice versa, digital preservation
is so far neglected in the design-and-construction process. In the
last 5 years, Building Information Modeling (BIM) has seen a
growing adoption in the architecture and construction domains,
marking a large step towards much needed interoperability. The
open standard IFC (Industry Foundation Classes) is one way in
which data is exchanged in BIM processes. This paper presents a
first digital preservation based look at BIM processes,
highlighting the history and adoption of the methods as well as
the open file format standard IFC (Industry Foundation Classes)
as one way to store and preserve BIM data
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Free-text keystroke dynamics authentication with a reduced need for training and language independency
This research aims to overcome the drawback of the large amount of training data required
for free-text keystroke dynamics authentication. A new key-pairing method, which is based
on the keyboard’s key-layout, has been suggested to achieve that. The method extracts
several timing features from specific key-pairs. The level of similarity between a user’s
profile data and his or her test data is then used to decide whether the test data was provided
by the genuine user. The key-pairing technique was developed to use the smallest amount of
training data in the best way possible which reduces the requirement for typing long text in
the training stage. In addition, non-conventional features were also defined and extracted
from the input stream typed by the user in order to understand more of the users typing
behaviours. This helps the system to assemble a better idea about the user’s identity from the
smallest amount of training data. Non-conventional features compute the average of users
performing certain actions when typing a whole piece of text. Results were obtained from the
tests conducted on each of the key-pair timing features and the non-conventional features,
separately. An FAR of 0.013, 0.0104 and an FRR of 0.384, 0.25 were produced by the timing
features and non-conventional features, respectively. Moreover, the fusion of these two
feature sets was utilized to enhance the error rates. The feature-level fusion thrived to reduce
the error rates to an FAR of 0.00896 and an FRR of 0.215 whilst decision-level fusion
succeeded in achieving zero FAR and FRR. In addition, keystroke dynamics research suffers
from the fact that almost all text included in the studies is typed in English. Nevertheless, the
key-pairing method has the advantage of being language-independent. This allows for it to be
applied on text typed in other languages. In this research, the key-pairing method was applied
to text in Arabic. The results produced from the test conducted on Arabic text were similar to
those produced from English text. This proves the applicability of the key-pairing method on
a language other than English even if that language has a completely different alphabet and
characteristics. Moreover, experimenting with texts in English and Arabic produced results
showing a direct relation between the users’ familiarity with the language and the
performance of the authentication system