Papers by Victor Jesus Mendez
Proceedings of the 4th International Conference on Complexity, Future Information Systems and Risk, 2019
The stock market plays a major role in the entire financial market. How to obtain effective tradi... more The stock market plays a major role in the entire financial market. How to obtain effective trading signals in the stock market is a topic that stock market has long been discussing. This paper first reviews the Deep Reinforcement Learning theory and model, validates the validity of the model through empirical data, and compares the benefits of the three classical Deep Reinforcement Learning models. From the perspective of the automated stock market investment transaction decision-making mechanism, Deep Reinforcement Learning model has made a useful reference for the construction of investor automation investment model, the construction of stock market investment strategy, the application of artificial intelligence in the field of financial investment and the improvement of investor strategy yield.
This paper gives an explanation about the definition of Big Data, Big Data Analytics and how they... more This paper gives an explanation about the definition of Big Data, Big Data Analytics and how they influence education in terms of benefits and ethical issues. First of all, this paper illustrates the applications of big data analytics in educational context and three benefits to education. Then, it explains ethical issues arisen during the usage of Big Data Analytics. It then discloses the ethical issues of Big Data Analytics employed in the education context from the aspects of individuals and the goal of education. Finally, this paper provides several recommendations to deal with current or potential ethical issues due to the applications of big data analytics in the area of education.
Proceedings of International Symposium on Grids and Clouds 2015 — PoS(ISGC2015), 2016
Cloud Computing is emerging today as the new approach followed by computing centres, since the fl... more Cloud Computing is emerging today as the new approach followed by computing centres, since the flexibility the Cloud provides is a powerful component to manage their resources. Through the use of virtualization, cloud promise to address with the same shared set of physical resources a large user base with different needs. However, virtualization may induce significant performance penalties for the demanding scientific computing workloads. This work presents an evaluation of the usefulness of the current cloud computing services for scientific applications. The performance of a sample of High Energy Physics (HEP) software running in a Kernel-based Virtual Machine (KVM) under different setups is analyzed with the use of a multivariate analysis of variance (MANOVA). While clouds are still changing, our results indicate that the current cloud services have to take into account the different setups of Cores and Memory in order to get reasonable performances in HEP-Software.
Proceedings of International Symposium on Grids and Clouds (ISGC) 2014 — PoS(ISGC2014), 2014
DIRAC has evolved from a framework for distributed computing matters operated by the final user, ... more DIRAC has evolved from a framework for distributed computing matters operated by the final user, to a platform that can also be used from third-party Virtual Research Environments (VRE), Science Gateways (SG) or distributed computing applications. Therefore, DIRAC has become a platform providing distributed computing interoperability and high level services for science. For this purpose, DIRAC supports several Application Programming Interfaces (API) designed for a versatile programming model in different developing scenarios. This paper presents such scenarios categorized by the location of the API client. Thus, a first scenario is an application server powered by DIRAC services. Second, a web browser running embedded DIRAC calls, for dynamic web client composition. Third scenario is a DIRAC Platform as a Service (PaaS) powering distributed applications with High Throughput Computing (HTC) on the client side. This paper describes the underlying DIRAC architecture and the main functionalities of each API and developing scenario. Overall DIRAC is a coherent toolkit that enables a wide range of component developments like service for scientific applications, web plugs or PaaS agents.
HortTechnology, 1996
Refrigerated (2 °C) controlled atmospheres significantly increased the mortality of green peach a... more Refrigerated (2 °C) controlled atmospheres significantly increased the mortality of green peach aphids [Myzus persicae (Sulzer)] and western flower thrips [Frankliniella occidentalis (Pergande)] in laboratory experiments. However, insect mortality during marine shipment in mixedload containers at 0.5 °C did not significantly increase in a controlled atmosphere. In laboratory experiments, mortality of green peach aphids ranged from 32.8% in the refrigerated control to 96.8% after storage in 0.10% O2 for 4 d followed by 7 d in 3% O2 with 5% CO2. When stored under these same conditions, western flower thrips mortality was 71% compared to 16% mortality in the refrigerated control. Following an 11-day marine shipment from California to Guam in a controlled atmosphere, vase life was extended for most of the 20 California cut-flower and foliage products compared to those shipped in the refrigerated air control.
PLOS ONE, 2018
The procurement of high-quality lithic resources is amongst the most indicative processes of deci... more The procurement of high-quality lithic resources is amongst the most indicative processes of decision-making in the archaeology of early human groups peopling the Americas. Directly dated deposits from quarry workshops have been absent of the late Pleistocene record of South America. We present the results of the excavations of a high-quality translucent quartz crystal workshop that yielded radiocarbon-dated coherently layered stratigraphic deposits that shed light into the behavior of the initial stages of lithic procurement. Based on a detailed analysis of the context of the Valiente site (32˚S, Chile, South America), we discuss the stages of bifacial production of point technology. The deposit produced evidence of cumulative occupations over the period between 12,630 and 11,320 calibrated years before present. This~1,300-year span is coincidental with a major environmental step-wise drying trend as indicated by the local and regional pollen records. Furthermore, it is synchronous to the process in which natural landscapes became the earliest taskscapes in the region, thereby encompassing major cultural changes related to the organization of the land use. These results are discussed in the frame of contemporaneous archaeological data to discuss specific aspects of technology and decision-making of the earliest settlers of South America.
SSRN Electronic Journal, 2014
This paper analyzes the effect of firm-and country-level determinants on debt maturity structure ... more This paper analyzes the effect of firm-and country-level determinants on debt maturity structure and how this effect varies across countries. Results for 39 countries indicate that firm-level variables such as asset maturity, size, firm quality and leverage affect debt maturity structure. While the efficiency of the legal system and the bank concentration show a positive relationship with debt maturity, the degree of investor protection and the weight of banks in the economy have a negative effect on firm debt maturity. However, these firm-and country-level determinants vary according to firm size, institutional and legal environment, and banking structure of the country. The higher the level of legal efficiency, the higher the fulfillment of the agency cost and signaling hypotheses and the lower the validity of the matching hypothesis.
Revista Colombiana De Gastroenterologia, Sep 1, 2007
Revista Colombiana De Gastroenterologia, Mar 1, 2010
Procedia Computer Science, 2015
BigDataDIRAC is a Big Data solution with a Distributed Infrastructure with Remote Agent Control (... more BigDataDIRAC is a Big Data solution with a Distributed Infrastructure with Remote Agent Control (DIRAC) access point. Users have the opportunity to access multiple Big Data resources scattered in different geographical areas, such as access to grid resources. This approach opens the possibility of offering not only grid and cloud to the users, but also Big Data resources from the same DIRAC environment. In this work, we describe a system to allow access to a federation of Big Data resources, including load balancing, using DIRAC. Our results demonstrate the ability of BigDataDIRAC to manage jobs driven by dataset location stored in the Hadoop File System (HDFS) of the Hadoop distributed clusters. DIRAC is used to monitor the execution, collect the necessary statistical data, and upload the results from the remote HDFS to the SandBox Storage machine. Performance results demonstrate that BigDataDIRAC load balancing is able to aggregate resources in an efficient manner.
Molecular Physics, 1967
The free radical CH3CO2 is identified in γ-irradiated polycrystalline sodium acetate. The observe... more The free radical CH3CO2 is identified in γ-irradiated polycrystalline sodium acetate. The observed spectrum is compared with predictions based upon simple Hückel calculations using the hetero atom model of the methyl group.
2013 World Haptics Conference (WHC), 2013
Trilateral haptic systems can be modeled as three-port networks. Analysis of coupled stability of... more Trilateral haptic systems can be modeled as three-port networks. Analysis of coupled stability of a three-port network can be accomplished in either the passivity or the absolute stability frameworks assuming all three ports are connected to passive but otherwise unknown terminations. This paper first reviews our recent results in terms of passivity and absolute stability criteria for general threeport networks-both criteria are founded on the properties of a positive-real Hermitian matrix. Next, we show that the absolute stability criterion is less conservative than the passivity criterion and that the two criteria become the same when the trilateral system is represented by a reciprocal immitance matrix. Then, to show how the two criteria may be utilized at the system design stage, we apply them to the problem of designing controllers for a dual-user haptic teleoperation system. Using the two criteria, controllers are then designed and compared in terms of conservatism and performance in simulations.
Cuadernos de Economía y Dirección de la Empresa, 2009
Advanced Robotics, 2014
This paper presents a novel criterion to study the stability of multilateral teleoperation system... more This paper presents a novel criterion to study the stability of multilateral teleoperation systems based on passivity. Such systems (modelled as-port networks) have recently found interesting applications in cooperative haptic teleoperation and haptic-assisted training. The criterion provides researchers with an analytical, closed-form, necessary and sufficient condition useful for both analysis and design of multilateral haptic teleoperation systems. The paper shows that when = 2 the proposed conditions reduce to the wellknown Raisbeck's passivity criterion for 2-port networks. The proposed conditions are used to study the passivity (and consequently the stability) of a dual-user haptic system for control of a single teleoperated robot. Simulations and experiments are performed to further test the validity of the proposed criterion.
49th IEEE Conference on Decision and Control (CDC), 2010
1. This paper presents a criterion for passivity of nport networks, which can be used to model mu... more 1. This paper presents a criterion for passivity of nport networks, which can be used to model multilateral systems involving haptic information sharing between a number of users. Such systems have recently found interesting applications in both cooperative haptic teleoperation and haptics-assisted training. The criterion presented in Theorem 1, which is necessary and sufficient for passivity of the n-port network, imposes 2n conditions on the immitance parameters of the network and on the residues of the immitance parameters at their imaginary-axis poles. It is shown that when n = 2, the proposed conditions reduce to the well-known Raisbeck's passivity criterion for two-port networks. Another special case for which the proposed criterion has been simplified corresponds to three-port networks. Finally, the passivity of a dual-user haptic system for control of a single teleoperated robot is investigated.
IEEE Latin America Transactions, 2011
The report discusses localizing paramagnetic probes (spin labels) within the lipid regions of cel... more The report discusses localizing paramagnetic probes (spin labels) within the lipid regions of cell membranes and looking for changes in motion of these membrane regions as a function of increasing pressure and decreasing temperature, information basic to establishing changes ...
Spectroscopy Letters, 1974
Abstract Rabbit alveolar macrophages were labeled with fatty acid-derived spin labels and the eff... more Abstract Rabbit alveolar macrophages were labeled with fatty acid-derived spin labels and the effects of both hydrostatic pressure and temperature upon the fluidity of cell lipids were observed. The alveolar macrophage membrane is significantly more fluid than the erythrocyte membrane, with a value of 2T of 52.1 ± 0.7 gauss as compared to a literature value of 56.2 ± 0.8 gauss for erythrocyte ghosts. Arrhenius plots of the effects of temperature upon membrane lipids exhibit a constant slope as the temperature is reduced until a temperature of 2–3°C is obtained, at which point an abrupt change of slope is encountered indicating a lipid phase transition. When the temperature is held constant and hydrostatic pressure is applied in increasing increments, membrane lipids again exhibit a gradual, consistent decrease in fluidity. Moderate pressures in the range of atmospheric to 4000 psi were employed; and for the cells studied, an increase in pressure of 1000 psi appears roughly equivalent to a temperature redu...
Uploads
Papers by Victor Jesus Mendez