• We develop distributed FM-Index and CBM algorithms for scalable compressed pattern matching on large genomic collections using Apache Spark. • Weconductathoroughperformanceevaluationbasedonstandardbenchmarksandmetricsusedindistributedalgorithm analysis. • We provide a publicly available software library to easily integrate distributed compressed pattern matching into genomic data processing pipelines without requiring a deep distributed programming expertise. Compressive genomics leverages compressed data representations to enhance the efficiency of bioinformatics tasks like sequence comparison and search. Surprisingly, the fundamental operation of pattern matching on large DNA sequence collections remains unexplored in the realm of genomic analysis. However, distributed systems like Spark offer the scalability necessary to process increasingly large genomic datasets efficiently. We present the first Spark-based implementation of the FM-Index and Compressed Boyer-Moore (CBM) algorithms, evaluating their performance and providing insights into their advantages for large-scale bioinformatics applications. A comprehensive experimental study demonstrates clear performance gains over uncompressed approaches. Furthermore, we introduce SparkGeco , a distributed compressive genomics software library designed to simplify the integration of FM-Index and CBM algorithms into DNA sequence analysis pipelines within Apache Spark, thus supporting the development of efficient and scalable genomic analysis workflows. This work provides a concrete step towards high-performance, data-centric eScience solutions in computational biology.

The outbreak of digital devices on the Internet, the exponential diffusion of data (images, video, audio, and text), along with their manipulation/generation also by artificial intelligence models, such as generative adversarial networks, have created a great deal of concern in the field of forensics. A malicious use can affect relevant application domains, which often include counterfeiting biomedical images and deceiving biometric authentication systems, as well as their use in scientific publications, in the political world, and even in school activities. It has been demonstrated that manipulated pictures most likely represent indications of malicious behavior, such as photos of minors to promote child prostitution or false political statements. Following this widespread behavior, various forensic techniques have been proposed in the scientific literature over time both to defeat these spoofing attacks as well as to guarantee the integrity of the information. Focusing on image forensics, which is currently a very hot topic area in multimedia forensics, this article will present the whole scenario in which a target image could be modified. The aim of this comprehensive survey will be (1) to provide an overview of the types of attacks and contrasting techniques and (2) to evaluate to what extent the former can deceive prevention methods and the latter can identify counterfeit images. The results of this study highlight how forgery detection techniques, sometimes limited to a single type of real scenario, are not able to provide exhaustive countermeasures and could/should therefore be combined. Currently, the use of neural networks, such as convolutional neural networks, is already heading, synergistically, in this direction.

Abstract Multimodal emotion recognition has attracted a great deal of attention in recent years, with new interesting applications now being considered. One promising application is in the digital image forensics fields where, for example, it gives the possibility to automatically highlight subjects that are in pain, in digital images under examination, by analyzing their facial expressions. However, finding an image that represents a possible crime leaves the problem of identifying the device used to take the image open. Such a problem has been addressed by Source Camera Identification algorithms (SCI, for short). These algorithms analyze some features hidden in a target image to find traces left by the sensor that captured the image. A particularly challenging case is when the candidate source cameras for an image under investigation are of the same manufacturer and model. A fair and universal assessment of these algorithms is only possible if standard datasets are used for their benchmarking. However, our comprehensive analysis has shown that the majority of the datasets proposed so far contain a collection of images taken with different types of cameras, mostly smartphones. We fill this gap by presenting UNISA2020, a novel image dataset that contains a large collection of real-world images taken with multiple conventional digital cameras of the same type. The images in our dataset have been assembled so as to avoid artifacts that could negatively affect the identification process. To validate our dataset, we also performed a comparative experimental analysis to investigate the performance of an SCI reference algorithm when running on our dataset as well as on other SCI standard datasets.

Some scientific studies involve huge amounts of bioinformatics data that cannot be analyzed on personal computers usually employed by researchers for day-to-day activities but rather necessitate effective computational infrastructures that can work in a distributed way. For this purpose, distributed computing systems have become useful tools to analyze large amounts of bioinformatics data and to generate relevant results on virtual environments, where software can be executed for hours or even days without affecting the personal computer or laptop of a researcher. Even if distributed computing resources have become pivotal in multiple bioinformatics laboratories, often researchers and students use them in the wrong ways, making mistakes that can cause the distributed computers to underperform or that can even generate wrong outcomes. In this context, we present here ten quick tips for the usage of Apache Spark distributed computing systems for bioinformatics analyses: ten simple guidelines that, if taken into account, can help users avoid common mistakes and can help them run their bioinformatics analyses smoothly. Even if we designed our recommendations for beginners and students, they should be followed by experts too. We think our quick tips can help anyone make use of Apache Spark distributed computing systems more efficiently and ultimately help generate better, more reliable scientific results.

MOTIVATION: Alignment-free (AF) distance/similarity functions are a key tool for sequence analysis. Experimental studies on real datasets abound and, to some extent, there are also studies regarding their control of false positive rate (Type I error). However, assessment of their power, i.e. their ability to identify true similarity, has been limited to some members of the D2 family. The corresponding experimental studies have concentrated on short sequences, a scenario no longer adequate for current applications, where sequence lengths may vary considerably. Such a State of the Art is methodologically problematic, since information regarding a key feature such as power is either missing or limited. RESULTS: By concentrating on a representative set of word-frequency-based AF functions, we perform the first coherent and uniform evaluation of the power, involving also Type I error for completeness. Two alternative models of important genomic features (CIS Regulatory Modules and Horizontal Gene Transfer), a wide range of sequence lengths from a few thousand to millions, and different values of k have been used. As a result, we provide a characterization of those AF functions that is novel and informative. Indeed, we identify weak and strong points of each function considered, which may be used as a guide to choose one for analysis tasks. Remarkably, of the 15 functions that we have considered, only four stand out, with small differences between small and short sequence length scenarios. Finally, to encourage the use of our methodology for validation of future AF functions, the Big Data platform supporting it is public. AVAILABILITY AND IMPLEMENTATION: The software is available at: https://github.com/pipp8/power_statistics. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Following publication of the original article [1], the authors identified that the affiliations of Giuseppe Cattaneo and Raffaele Giancarlo were interchanged. The correct affiliations are given below. The correct affiliation of Giuseppe Cattaneo is: 2Dipartimento di Informatica, Università di Salerno, Fisciano, Italy. The correct affiliation of Raffaele Giancarlo is: 3Dipartimento di Matematica ed Informatica, Università di Palermo, Palermo, Italy. The original article [1] has been corrected.

MOTIVATION: Alignment-free distance and similarity functions (AF functions, for short) are a well-established alternative to pairwise and multiple sequence alignments for many genomic, metagenomic and epigenomic tasks. Due to data-intensive applications, the computation of AF functions is a Big Data problem, with the recent literature indicating that the development of fast and scalable algorithms computing AF functions is a high-priority task. Somewhat surprisingly, despite the increasing popularity of Big Data technologies in computational biology, the development of a Big Data platform for those tasks has not been pursued, possibly due to its complexity. RESULTS: We fill this important gap by introducing FADE, the first extensible, efficient and scalable Spark platform for alignment-free genomic analysis. It supports natively eighteen of the best performing AF functions coming out of a recent hallmark benchmarking study. FADE development and potential impact comprises novel aspects of interest. Namely, (i) a considerable effort of distributed algorithms, the most tangible result being a much faster execution time of reference methods like MASH and FSWM; (ii) a software design that makes FADE user-friendly and easily extendable by Spark non-specialists; (iii) its ability to support data- and compute-intensive tasks. About this, we provide a novel and much needed analysis of how informative and robust AF functions are, in terms of the statistical significance of their output. Our findings naturally extend the ones of the highly regarded benchmarking study, since the functions that can really be used are reduced to a handful of the eighteen included in FADE. AVAILABILITYAND IMPLEMENTATION: The software and the datasets are available at https://github.com/fpalini/fade. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

BACKGROUND: Storage of genomic data is a major cost for the Life Sciences, effectively addressed via specialized data compression methods. For the same reasons of abundance in data production, the use of Big Data technologies is seen as the future for genomic data storage and processing, with MapReduce-Hadoop as leaders. Somewhat surprisingly, none of the specialized FASTA/Q compressors is available within Hadoop. Indeed, their deployment there is not exactly immediate. Such a State of the Art is problematic. RESULTS: We provide major advances in two different directions. Methodologically, we propose two general methods, with the corresponding software, that make very easy to deploy a specialized FASTA/Q compressor within MapReduce-Hadoop for processing files stored on the distributed Hadoop File System, with very little knowledge of Hadoop. Practically, we provide evidence that the deployment of those specialized compressors within Hadoop, not available so far, results in better space savings, and even in better execution times over compressed data, with respect to the use of generic compressors available in Hadoop, in particular for FASTQ files. Finally, we observe that these results hold also for the Apache Spark framework, when used to process FASTA/Q files stored on the Hadoop File System. CONCLUSIONS: Our Methods and the corresponding software substantially contribute to achieve space and time savings for the storage and processing of FASTA/Q files in Hadoop and Spark. Being our approach general, it is very likely that it can be applied also to FASTA/Q compression methods that will appear in the future. AVAILABILITY: The software and the datasets are available at https://github.com/fpalini/fastdoopc.

BACKGROUND: Distributed approaches based on the MapReduce programming paradigm have started to be proposed in the Bioinformatics domain, due to the large amount of data produced by the next-generation sequencing techniques. However, the use of MapReduce and related Big Data technologies and frameworks (e.g., Apache Hadoop and Spark) does not necessarily produce satisfactory results, in terms of both efficiency and effectiveness. We discuss how the development of distributed and Big Data management technologies has affected the analysis of large datasets of biological sequences. Moreover, we show how the choice of different parameter configurations and the careful engineering of the software with respect to the specific framework under consideration may be crucial in order to achieve good performance, especially on very large amounts of data. We choose k-mers counting as a case study for our analysis, and Spark as the framework to implement FastKmer, a novel approach for the extraction of k-mer statistics from large collection of biological sequences, with arbitrary values of k. RESULTS: One of the most relevant contributions of FastKmer is the introduction of a module for balancing the statistics aggregation workload over the nodes of a computing cluster, in order to overcome data skew while allowing for a full exploitation of the underlying distributed architecture. We also present the results of a comparative experimental analysis showing that our approach is currently the fastest among the ones based on Big Data technologies, while exhibiting a very good scalability. CONCLUSIONS: We provide evidence that the usage of technologies such as Hadoop or Spark for the analysis of big datasets of biological sequences is productive only if the architectural details and the peculiar aspects of the considered framework are carefully taken into account for the algorithm design and implementation.

In the last decade Digital Forensics has experienced several issues when dealing with network evidence. Collecting network evidence is difficult due to its volatility. In fact, such information may change overtime, may be stored on a server out jurisdiction or geographically far from the crime scene. On the other hand, the explosion of the Cloud Computing as the implementation of the Software as a Service (SaaS) paradigm is pushing users toward remote data repositories such as Dropbox, Amazon Cloud Drive, Apple iCloud, Google Drive, Microsoft OneDrive. In this paper is proposed a novel methodology for the collection of network evidence. In particular, it is focused on the collection of information from online services, such as web pages, chats, documents, photos and videos. The methodology is suitable for both expert and non-expert analysts as it “drives” the user through the whole acquisition process. During the acquisition, the information received from the remote source is automatically collected. It includes not only network packets, but also any information produced by the client upon its interpretation (such as video and audio output). A trusted-third-party, acting as a digital notary, is introduced in order to certify both the acquired evidence (i.e., the information obtained from the remote service) and the acquisition process (i.e., all the activities performed by the analysts to retrieve it). A proof-of-concept prototype, called LINEA, has been implemented to perform an experimental evaluation of the methodology.

Motivation: Information theoretic and compositional/linguistic analysis of genomes have a central role in bioinformatics, even more so since the associated methodologies are becoming very valuable also for epigenomic and meta-genomic studies. The kernel of those methods is based on the collection of k-mer statistics, i.e. how many times each k-mer in {A,C,G,T}k occurs in a DNA sequence. Although this problem is computationally very simple and efficiently solvable on a conventional computer, the sheer amount of data available now in applications demands to resort to parallel and distributed computing. Indeed, those type of algorithms have been developed to collect k-mer statistics in the realm of genome assembly. However, they are so specialized to this domain that they do not extend easily to the computation of informational and linguistic indices, concurrently on sets of genomes. Results: Following the well-established approach in many disciplines, and with a growing success also in bioinformatics, to resort to MapReduce and Hadoop to deal with 'Big Data' problems, we present KCH, the first set of MapReduce algorithms able to perform concurrently informational and linguistic analysis of large collections of genomic sequences on a Hadoop cluster. The benchmarking of KCH that we provide indicates that it is quite effective and versatile. It is also competitive with respect to the parallel and distributed algorithms highly specialized to k-mer statistics collection for genome assembly problems. In conclusion, KCH is a much needed addition to the growing number of algorithms and tools that use MapReduce for bioinformatics core applications. Availability and implementation: The software, including instructions for running it over Amazon AWS, as well as the datasets are available at http://www.di-srv.unisa.it/KCH. Contact: [email protected]. Supplementary information: Supplementary data are available at Bioinformatics online.

SUMMARY: MapReduce Hadoop bioinformatics applications require the availability of special-purpose routines to manage the input of sequence files. Unfortunately, the Hadoop framework does not provide any built-in support for the most popular sequence file formats like FASTA or BAM. Moreover, the development of these routines is not easy, both because of the diversity of these formats and the need for managing efficiently sequence datasets that may count up to billions of characters. We present FASTdoop, a generic Hadoop library for the management of FASTA and FASTQ files. We show that, with respect to analogous input management routines that have appeared in the Literature, it offers versatility and efficiency. That is, it can handle collections of reads, with or without quality scores, as well as long genomic sequences while the existing routines concentrate mainly on NGS sequence data. Moreover, in the domain where a comparison is possible, the routines proposed here are faster than the available ones. In conclusion, FASTdoop is a much needed addition to Hadoop-BAM. AVAILABILITY AND IMPLEMENTATION: The software and the datasets are available at http://www.di.unisa.it/FASTdoop/ . CONTACT: [email protected]. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

In this paper, we explore the possibility to solve a commonly-known digital image forensics problem, the Source Camera Identification (SCI) problem, using a distributed approach. The SCI problem requires to recognize the camera used to acquire a given digital image, distinguishing even among cameras of the same brand and model. The solution we present is based on the algorithm by Lukas Fridrich, as it is recognized by many as the reference solution for this problem, and is formulated according to the MapReduce paradigm, as implemented by the Hadoop framework. The first implementation we coded was straightforward to obtain as we leveraged the ability of the Hadoop framework to turn a stand-alone Java application into a distributed one with very few interventions on its original source code. However, our first experimental results with this code were not encouraging. Thus, we conducted a careful profiling activity that allowed us to pinpoint some serious performance issues arising with this vanilla porting of the algorithm. We then developed several optimizations to improve the performance of the Lukas algorithm by taking better advantage of the Hadoop framework. The out coming implementations have been subject to a thorough experimental analysis, conducted using a cluster of 33 commodity PCs and a data set of 5, 160 images. The experimental results show that the performance of our optimized implementations scale well with the number of computing nodes while exhibiting performance that are, at most, two times slower than the maximum speedup theoretically achievable.

The growing intelligence and popularity of smartphones and the advances in Mobile Ubiquitous Computing have resulted in rapid proliferation of data-sharing applications. Instances of these applications include pervasive social networking, games, file sharing and so on. In such scenarios, users are usually involved in selecting the peers with whom communication should take place, continuously facing trust issues. Unfortunately, providing trust support in a pervasive world is challenging due to peer mobility and lack in central control. We propose a novel approach that establishes trust leveraging users' profiles: humans today produce rich strings of unique data twenty-four hours a day. These information enables a task-aware trust model, namely a finer-grained model in which users are classified as trusted or not depending on the intended business activity. However, simply collecting user's interests may be insufficient to provide a reasonable trust management system. In order to enable the system to recognize malicious users, we include a recommendation subsystem based on the Wilson score confidence interval. It has been designed to be lightweight, minimizing battery depletion. It also protects user privacy. To make our approach fully deployable, it supports two modalities: a TPM-based one and a TPM-less one. The former gives more security guarantees and ensures a fully distributed approach. The latter, requires a Trusted Authority to avoid feedbacks to get tampered and is no more fully distributed.

In the last decade Digital Forensics has experienced several issues when dealing with network evidence. An analyst, which is in charge of managing evidence flowing over a network have to face problems due to the volatile nature of such information. In facts, such data may change over time, may be lying on a server out of the his jurisdiction, or geographically far from where the crime was committed. In this paper two methods to allow remote collection of network evidence produced by online services such as web pages, chats, documents, photos and videos are presented. They enable the analyst to drive the acquisition process through the online services considered potential sources of evidence. During the process, all data flowing through the network is automatically collected (i.e., all the IP packets). The second one also collects the graphical representation of the acquisition (e.g., how the browser visualizes such data). Both methods introduce a trusted third party (acting as a digital notary) which is in charge of collecting and ``certifying'' network evidence. Before closing the acquisition process, a detailed report of the collected evidence is generated and made available to the analyst along with the collected data. Cryptographic primitives are used to demonstrate ex post data integrity, how it has been acquired and the acquisition time. As a proof of concept two prototypes have been implemented. To enhance the Court confidence of the collected evidence, at the same time, the service could be run across multiple coordinated servers acquiring the same data from different point of the network.

Nowadays, Short Message Service (SMS) still represents the most used mobile messaging service. SMS messages are used in many different application fields, even in cases where security features, such as authentication and confidentiality between the communicators, must be ensured. Unfortunately, the SMS technology does not provide a built-in support for any security feature. This work presents SEESMS (Secure Extensible and Efficient SMS), a software framework written in Java which allows two peers to exchange encrypted and digitally signed SMS messages. The communication between peers is secured by using public-key cryptography. The key-exchange process is implemented by using a novel and simple security protocol which minimizes the number of SMS messages to use. SEESMS supports the encryption of a communication channel through the ECIES and the RSA algorithms. The identity validation of the contacts involved in the communication is implemented through the RSA, DSA and ECDSA signature schemes. SEESMS is able to certify the phone number of the peers using the framework. Additional cryptosystems can be coded and added to SEESMS as plug-ins. Special attention has been devoted to the implementation of an efficient framework in terms of energy consumption and execution time. This efficiency is obtained in two steps. First, all the cryptosystems available in the framework are implemented using mature and fully optimized cryptographic libraries. Second, an experimental analysis was conducted to determine which combination of cryptosystems and security parameters were able to provide a better trade-off in terms of speed/security and energy consumption. This experimental analysis has also been useful to expose some serious performance issues affecting the cryptographic libraries which are commonly used to implement security features on mobile devices.

In this paper we propose a novel approach to the learning of cryptographic protocols, based on a collaborative role-based visualization system, DISCERN, that helps students to understand a protocol by actively engaging them in a simulation of its execution. In DISCERN, each student shares a visual e

In this paper we present a SOAP extension for protecting the privacy of users of a Web service. This extension allows a user to prove to a remote SOAP server to be member of a trusted group without revealing his/her identity. Our extension has been designed as to ensure interoperability among SOAP applications written in different programming languages. We developed also some implementations of our extension using different programming languages. Moreover, we conducted an extensive experimentation of our implementation to prove its feasibility in a real-world context. In sums, our work suggests that privacy can be added to Web services with very little impact on the application developer and without compromising the performance of Web services.

JIVE (Java interactive software visualization environment) is a system for the visualization of Java coded algorithms and data structures. It supports the rapid development of interactive animations through the adoption of an object oriented approach. JIVE introduces several significant innovations such as a distributed architecture able to separate transparently the visualization activity from the underlying communication needed to support it. Therefore, it becomes possible to use JIVE in a variety of scenarios ranging from debugging algorithms to software visualization in virtual classrooms environments. Moreover, JIVE uses a zoomable user interface for representing algorithms: seamless visualization of both small and large data sets is achieved by using semantic zooming. Finally, JIVE comes with a collection of already animated data types including data structures provided by the Java standard library

We present a report on JSEB (Java Scalable Service Builder) whose goal is to offer programmers a tool that can be used to efficiently add scalability and fault-tolerance to a replicated service in cluster(s) of workstations.

Electronic Commerce (EC) is currently one of the fastest growing and most practically relevant application areas of distributed systems technologies. It is based on the economic aspects of commercial trading patterns combined with distributed computing systems technology. It is a market environment that is characterized by low transaction costs, a large number of market participants, and easy online access to services and goods offered. It also implies a set of rules and policies for the successful organization of business transactions. EC involves more than simple online transactions, it encompasses diverse activities as conducting market research, identifying opportunities and partners, cultivating relationships with customers and suppliers, document exchange and customer modeling. Our paper deals with the latter aspect of EC. We introduce here a model for developing a symmetric adaptive system for EC on the World Wide Web. Our main contribution is that the model is, by all means, symmetric: we model both customers and goods and make both their profiles change as a consequence of a customer buying a certain product. The symmetry in our model greatly simplifies the approach and the queries, giving some insights on the formalization of the allowed queries that were, in way, unexpected. Furthermore, the model itself can provide an easy-to-evaluate measure for the confidence in adapting its response to any given customer and is able to provide useful feedback to the manager, then allowing, so to speak, "manual adjustment" that can help the behaviour of the system in the future.

Proposes a new framework to implement a complete logic programming system. This framework is composed of a set of new mechanisms intended to give high level and safe means to manage a computation history. Upon this framework the authors developed a logic programming environment prototype, called MxLog, featuring a complete Prolog-II interpreter and its debugging environment. This prototype has been realised following a new implementation philosophy independent of hardware constraints and based on an incremental strategy, expressed in terms of agents in a sequential open system.>