Log-Based Session Profiling and Online Behavioral Prediction in E-Commerce Websites

Improvements to customer experience give companies a competitive advantage, as understanding customers' behaviors allows e-commerce companies to enhance their marketing strategies by means of recommendation techniques and the customization of products and services. This is not a simple task, and it becomes more difficult when working with anonymous sessions since no historical information of the user can be applied. In this article, analysis and clustering of the clickstreams of past anonymous sessions are used to synthesize a prediction model based on a neural network. The model allows for prediction of a user's profile after a few clicks of an online anonymous session. This information can be used by the e-commerce's decision system to generate online recommendations and better adapt the offered services to the customer's profile

Reducing the price of resource provisioning using EC2 spot instances with prediction models

The increasing demand of computing resources has boosted the use of cloud computing providers. This has raised a new dimension in which the connections between resource usage and costs have to be considered from an organizational perspective. As a part of its EC2 service, Amazon introduced spot instances (SI) as a cheap public infrastructure, but at the price of not ensuring reliability of the service. On the Amazon SI model, hired instances can be abruptly terminated by the service provider when necessary. The interface for managing SI is based on a bidding strategy that depends on non-public Amazon pricing strategies, which makes complicated for users to apply any scheduling or resource provisioning strategy based on such (cheaper) resources. Although it is believed that the use of the EC2 SIs infrastructure can reduce costs for final users, a deep review of literature concludes that their characteristics and possibilities have not yet been deeply explored. In this work we present a framework for the analysis of the EC2 SIs infrastructure that uses the price history of such resources in order to classify the SI availability zones and then generate price prediction models adapted to each class. The proposed models are validated through a formal experimentation process. As a result, these models are applied to generate resource provisioning plans that get the optimal price when using the SI infrastructure in a real scenario. Finally, the recent changes that Amazon has introduced in the SI model and how this work can adapt to these changes is discussed

Analysis of Users' Behavior in Structured e-Commerce Websites

Online shopping is becoming more and more common in our daily lives. Understanding users'' interests and behavior is essential to adapt e-commerce websites to customers'' requirements. The information about users'' behavior is stored in the Web server logs. The analysis of such information has focused on applying data mining techniques, where a rather static characterization is used to model users'' behavior, and the sequence of the actions performed by them is not usually considered. Therefore, incorporating a view of the process followed by users during a session can be of great interest to identify more complex behavioral patterns. To address this issue, this paper proposes a linear-temporal logic model checking approach for the analysis of structured e-commerce Web logs. By defining a common way of mapping log records according to the e-commerce structure, Web logs can be easily converted into event logs where the behavior of users is captured. Then, different predefined queries can be performed to identify different behavioral patterns that consider the different actions performed by a user during a session. Finally, the usefulness of the proposed approach has been studied by applying it to a real case study of a Spanish e-commerce website. The results have identified interesting findings that have made possible to propose some improvements in the website design with the aim of increasing its efficiency

A cloud-based parallel system for locating customers in indoor malls

Advances in techniques of locating mobile users have promoted the development of marketing campaigns based on customers’ location. WiFi-based location methods have proven their usefulness in tracking and locating customers within a indoor mall. Nevertheless, in some cases the performance of these methods prevents them from being used in real scenarios. In this paper, we have faced the problem of improving the execution time and reducing the cost of one of these WiFi-based location methods. Parallel programming techniques, service-oriented technologies and the cloud computing paradigm have been combined to solve efficiently these problems. The resulting system has been deployed in the Amazon EC2 environment, evaluating different configuration and deployment options

From lean production to lean 4.0: a systematic literature review with a historical perspective

Over recent decades, the increasing competitiveness of markets has propagated the term “lean” to describe the management concept for improving productivity, quality, and lead time in industrial as well as services operations. Its overuse and linkage to different specifiers (surnames) have created confusion and misunderstanding as the term approximates pragmatic ambiguity. Through a systematic literature review, this study takes a historical perspective to analyze 4962 papers and 20 seminal books in order to clarify the origin, evolution, and diversification of the lean concept. Our main contribution lies in identifying 17 specifiers for the term “lean” and proposing four mechanisms to explain this diversification. Our research results are useful to both academics and practitioners to return to the Lean origins in order to create new research areas and conduct organizational transformations based on solid concepts. We conclude that the use of “lean” as a systemic thinking is likely to be further extended to new research fields

Parallel computation of the reachability graph of petri net models with semantic information

Formal verification plays a crucial role when dealing with correctness of systems. In a previous work, the authors proposed a class of models, the Unary Resource Description Framework Petri Nets (U-RDF-PN), which integrated Petri nets and (RDF-based) semantic information. The work also proposed a model checking approach for the analysis of system behavioural properties that made use of the net reachability graph. Computing such a graph, specially when dealing with high-level structures as RDF graphs, is a very expensive task that must be considered. This paper describes the development of a parallel solution for the computation of the reachability graph of U-RDF-PN models. Besides that, the paper presents some experimental results when the tool was deployed in cluster and cloud frameworks. The results not only show the improvement in the total time required for computing the graph, but also the high scalability of the solution, which make it very useful thanks to the current (and future) availability of cloud infrastructures

Use of electrospinning to develop antimicrobial biodegradable multilayer systems: encapsulation of cinnamaldehyde and their physicochemical characterization

In this work, three active bio-based multilayer structures, using a polyhydroxybutyrate-co-valerate film with a valerate content of 8 % (PHBV8) as support, were developed. To this end, a zein interlayer with or without cinnamaldehyde (CNMA) was directly electrospun onto one side of the PHBV8 film and the following systems were developed: (1) without an outer layer; (2) using a PHBV8 film as outer layer; and (3) using an alginate-based film as outer layer. These multilayer structures were characterized in terms of water vapour and oxygen permeabilities, transparency, intermolecular arrangement and thermal properties. The antimicrobial activity of the active bio-based multilayer systems and the release of CNMA in a food simulant were also evaluated. Results showed that the presence of different outer layers reduced the transport properties and transparency of the multilayer films. The active bio-based multilayer systems showed antibacterial activity against Listeria monocytogenes being the multilayer structure prepared with CNMA and PHBV outer layers (PHBV + zein/CNMA + PHBV) the one that showed the greater antibacterial activity. The release of CNMA depended on the multilayer structures, where both Fick's and Case II transport-polymer relaxation explained the release of CNMA from the multilayer systems.Acknowledgments: Miguel A. Cerqueira (SFRH/BPD/72753/2010) andAnaI.Bourbon(SFRH/BD/73178/2010)arerecipientofafellowship from the Fundação para a Ciência e Tecnologia (FCT, POPH-QREN and FSE Portugal). J.L. Castro-Mayorga is supported by the Administrative Department of Science, Technology and Innovation (Colciencias) of Colombian Government. M. J. Fabra is a recipient of a Ramon y Cajal contract (RyC-2014-158) from the Spanish Ministry of Economy and Competitiveness. This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and of the Project RECI/BBB-EBI/ 0179/2012 (FCOMP-01-0124-FEDER-027462). The support of EU Cost Action MP1206 is gratefully acknowledged

Animal thermoregulation: a review of insulation, physiology and behaviour relevant to temperature control in buildings

Birds and mammals have evolved many thermal adaptations that are relevant to the bioinspired design of temperature control systems and energy management in buildings. Similar to many buildings, endothermic animals generate internal metabolic heat, are well insulated, regulate their temperature within set limits, modify microclimate and adjust thermal exchange with their environment. We review the major components of animal thermoregulation in endothermic birds and mammals that are pertinent to building engineering, in a world where climate is changing and reduction in energy use is needed. In animals, adjustment of insulation together with physiological and behavioural responses to changing environmental conditions fine-tune spatial and temporal regulation of body temperature, while also minimizing energy expenditure. These biological adaptations are characteristically flexible, allowing animals to alter their body temperatures to hourly, daily, or annual demands for energy. They exemplify how buildings could become more thermally reactive to meteorological fluctuations, capitalising on dynamic thermal materials and system properties. Based on this synthesis, we suggest that heat transfer modelling could be used to simulate these flexible biomimetic features and assess their success in reducing energy costs while maintaining thermal comfort for given building types

Synthesis of tetranuclear rhodium and iridium complexes directed by 6-mercaptopyridin-2-ol: Electrochemical behavior, chemical oxidation, and coordination chemistry

The new ligand 6-mercapto-2(1 H)-pyridone (H2PySO) has been prepared in good yield by reaction of 6-chloro-pyridin-2-ol with NaSH. Reaction of the salt K2PySO, generated in situ, with the appropriate complex [M(μ-C1)(diolefin)]2affords the tetranuclear complexes [M 4(μ-PySO)2(diolefin)4] [M = Rh, diolefin = 1,5-cyclooctadiene (cod) (1), tetrafluorobenzobarralene (tfbb) (2); M = lr, diolefin = cod (3)]. The molecular structure of complex 1 has been determined by X-ray diffraction methods. The tetranuclear structure is supported by two S, N, Otridentate ligands exhibiting a 1κO, 2κN, 3:4κ2 S coordination mode. Carbonylation of the rhodium diolefin complexes at atmospheric pressure gives [Rh4(μ-PyS0)2(C0)8] (4). The carbonylation of 1 is partially reversible, and the mixed-ligand complex [Rh4(μ-PySO)2(cod)2(CO)4] (5) has been obtained as a single isomer. The reaction of 4 with triphenylphosphine gives the compound [Rh4(μ-PySO)2(CO)4(PPh 3)4] (6) which also exists as a single isomer of C 2 symmetry. The diolefin complexes are redox active and exhibit two one-electron oxidations at a platinum disk electrode in dichloromethane separated by approximately 0.5 V at potentials accessible by chemical oxidants. The tetranuclear complexes were selectively oxidized to the 63-electron mixed-valence cationic complexes [M4(μ-PySO)2(diolefin) 4]+(1a+, 2+, and 3+) by using AgCF3SO3 as oxidant and isolated as the triflate salts. Alternatively, the oxidation with [Cp2Fe]PF6 gives [Rh4(μ-PySO)2(cod)4][PF6] (1b+). The parameters obtained from the simulation of the electron paramagnetic resonance spectra of the oxidized species strongly suggest that the unpaired electron is delocalized over only two metal atoms in the complexes.The financial support from Ministerio de Educación y Ciencia (MEC/FEDER) Project CTQ2006-03973/BQU and Grant CSD2006-0015 Consolider Ingenio 2010 is gratefully acknowledged.Peer Reviewe

Role of COQ4 on mitochondrial DNA maintenance

Resumen del póster presentado en Mitochondrial Medicine, celebrado en Hinxton (Inglaterra) del 09 al 11 de mayo de 2018.Coenzyme Q (CoQ) is a lipidic molecule composed by a hydroquinone head and an isoprenoid chain. Since its discovery, several functions have been assigned to CoQ, being the transfer of electrons from complexes I and II to complex III in the mitochondrial respiratory chain the best known. CoQ also receives electrons from other dehydrogenases involved in different cellular processes and it is a potent membrane antioxidant. CoQ is endogenously synthesized by a set of enzymes forming a biosynthetic complex in the mitochondrial inner membrane, which has been mostly studied in yeast models. Defects in any of the genes coding for these proteins result in reduced levels of CoQ and, consequently, defects in energy production. COQ4 is one of the proteins involved in CoQ biosynthesis, but its exact enzymatic activity is still unknown. COQ4 KO HEK 293T-Rex/Flp-In cells generated by CRISPR/Cas9, as well as patient fibroblasts carrying mutations in COQ4 show the accumulation of a yet uncharacterised biosynthetic intermediate that lacks redox activity. Two candidate molecules have emerged from mass spectrometry analysis performed to identify this intermediate. On the other hand, the KO cells show a surprising phenotype related to mtDNA metabolism which may be due either to the lack of de novo synthesis of CoQ, to the biosynthetic complex instability itself, to the presence of the intermediate, or to a different and yet not characterized role of COQ4. Altogether, these results indicate a possible double function of the COQ4 protein