1,807 research outputs found
CODA Algorithm: An Immune Algorithm for Reinforcement Learning Tasks
This document presents the design of an algorithm that takes on its basis: reinforcement learning, learning from demonstration and most importantly Artificial Immune Systems. The main advantage of this algorithm named CODA (Cognition from Data). Is; it can learn from limited data samples- that is given a single example and the algorithm will create its own knowledge. The algorithm imitates from the Natural Immune System the clonal procedure for obtaining a repertoire of antibodies from a single antigen. It also uses the self-organised memory in order to reduce searching time in the whole action-state space by searching in specific clusters. CODA algorithm is presented and explained in detail in order to understand how these three principles are used. The algorithm is explained with pseudocode, flowcharts and block diagrams. The clonal/mutation results are presented with a simple example. It can be seen graphically how new data that has a completely new probability distribution. Finally, the first application where CODA is used, a humanoid hand is presented. In this application the algorithm created affordable grasping postures from limited examples, creates its own knowledge and stores data in memory data in memory in order to recognise whether it has been on a similar situation
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Security and Privacy Qualities of Medical Devices: An Analysis of FDA Postmarket Surveillance
Background: Medical devices increasingly depend on computing functions such as wireless communication and Internet connectivity for software-based control of therapies and network-based transmission of patients’ stored medical information. These computing capabilities introduce security and privacy risks, yet little is known about the prevalence of such risks within the clinical setting. Methods: We used three comprehensive, publicly available databases maintained by the Food and Drug Administration (FDA) to evaluate recalls and adverse events related to security and privacy risks of medical devices. Results: Review of weekly enforcement reports identified 1,845 recalls; 605 (32.8%) of these included computers, 35 (1.9%) stored patient data, and 31 (1.7%) were capable of wireless communication. Searches of databases specific to recalls and adverse events identified only one event with a specific connection to security or privacy. Software-related recalls were relatively common, and most (81.8%) mentioned the possibility of upgrades, though only half of these provided specific instructions for the update mechanism. Conclusions: Our review of recalls and adverse events from federal government databases reveals sharp inconsistencies with databases at individual providers with respect to security and privacy risks. Recalls related to software may increase security risks because of unprotected update and correction mechanisms. To detect signals of security and privacy problems that adversely affect public health, federal postmarket surveillance strategies should rethink how to effectively and efficiently collect data on security and privacy problems in devices that increasingly depend on computing systems susceptible to malware
Distinctive effects of eicosapentaenoic and docosahexaenoic acids in regulating neural stem cell fate are mediated via endocannabinoid signalling pathways
Emerging evidence suggests a complex interplay between the endocannabinoid system, omega-3 fatty acids and the immune system in the promotion of brain self-repair. However, it is unknown if all omega-3 fatty acids elicit similar effects on adult neurogenesis and if such effects are mediated or regulated by interactions with the endocannabinoid system. This study investigated the effects of DHA and EPA on neural stem cell (NSC) fate and the role of the endocannabinoid signalling pathways in these effects.
EPA, but not DHA, significantly increased proliferation of NSCs compared to controls, an effect associated with enhanced levels of the endocannabinoid 2-arachidonylglycerol (2-AG) and p-p38 MAPK, effects attenuated by pre-treatment with CB1 (AM251) or CB2 (AM630) receptor antagonists. Furthermore, in NSCs derived from IL-1β deficient mice, EPA significantly decreased proliferation and p-p38 MAPK levels compared to controls, suggesting a key role for IL-1β signalling in the effects observed. Although DHA similarly increased 2-AG levels in wild-type NSCs, there was no concomitant increase in proliferation or p-p38 MAPK activity. In addition, in NSCs from IL-1β deficient mice, DHA significantly increased proliferation without effects on p-P38 MAPK, suggesting effects of DHA are mediated via alternative signalling pathways. These results provide crucial new insights into the divergent effects of EPA and DHA in regulating NSC proliferation and the pathways involved, and highlight the therapeutic potential of their interplay with endocannabinoid signalling in brain repair
Control global para el péndulo con rueda de reacción
En el presente artículo se desarrolla e implementa un esquema de control, que usa una técnica no lineal conocida como Linealización por Realimentación y una estrategia de seguimiento de trayectoria, con el que se busca controlar de forma global el Péndulo con Rueda de Reacción. Tal esquema genera una señal de control que cancela la no linealidad de la planta y regula el error de seguimiento. Los resultados de la implementación práctica verifican la validez del planteamiento
Método iterativo para el cálculo de potenciales electrostáticos
Se presenta un método para obtener el potencial eléctrico en una región determinada del espacio, dadas las condiciones de frontera e incluso condiciones interiores. El método consiste en dividir la región en una rejilla sobre la cual se calcula el potencial usando promedios iterativos hasta obtener una estabilización en los valores. Los resultados se comparan con los obtenidos a través de la solución a la ecuación de Laplace y se muestran las ventajas del método en relación con su relativa simplicidad y su capacidad de resolver problemas más complejos. Se ilustra el caso bidimensional para facilitar la visualización de los resultados
Analytical and clinical evaluation of an electrochemiluminescence immunoassay for the determination of CA 125
The CA 125 II assay on the Elecsys(R) 2010 analyzer was evaluated in an
international multicenter trial. Imprecision studies yielded within-run
CVs of 0.8-3.3% and between-day CVs of 2.4-10.9%; CVs for total
imprecision in the manufacturer's laboratory were 2.4-7.8%. The linear
range of the assay extended to at least 4500 kilounits/L (three decades).
Interference from triglycerides (10.3 mmol/L), bilirubin (850 micromol/L),
hemoglobin (1.1 mmol/L), anticoagulants (plasma), and several widely used
drugs was undetectable. Method comparisons with five other CA 125 II
assays showed good correlation but differences in standardization. A 95th
percentile cutoff value of 35 kilounits/L was calculated from values
measured in 593 apparently healthy (pre- and postmenopausal) women. In 95%
of patients with benign gynecological diseases CA 125 was </=190
kilounits/L; 63% of patients with newly diagnosed ovarian carcinoma had
values >190 kilounits/L. A comparison of CA 125 values obtained with the
Elecsys test and with other common CA 125 tests in monitored patients
being treated for ovarian cancer showed identical patterns. In conclusion,
the Elecsys CA 125 II assay is linear over a broad range, yields precise
and accurate results, is free from interferences, and compares well with
other assays
Reviewable Life Sentences: The Colombian Case in a Constitutional Perspectiv
This article analyzes the legal concept of reviewable life sentences, considering doctrinal precedents and the concept’s applicability in comparative law, in such countries as England, Spain, China, the United States, and others. The article also includes a legal study of the most relevant cases presented to international tribunals, like the European Human Rights Court and the Austrian, Swiss, and German High Courts, where life imprisonment sentences are subject to review after partial completion. Finally, the article analyzes the prohibition of life imprisonment in Colombia that stems from a constitutional mandate as well as from international-treaty commitments, and the legal precedents established by the country’s Constitutional Court and Supreme Court.El presente artículo se ocupa del análisis de la figura jurídica de la prisión perpetua revisable, de acuerdo con sus antecedentes doctrinarios y su aplicabilidad en el derecho comparado, específicamente en países como Inglaterra, España, China, EE.UU., entre otros. Adicionalmente, se hace un estudio jurisprudencial de los casos más relevantes sometidos a consideración de Cortes internacionales, tal es el caso del Tribunal Europeo de Derechos Humanos y los Altos Tribunales de Austria, Suiza y Alemania, donde es sujeto de revisión la pena de prisión perpetua después de cumplida la condena por un determinado tiempo. Por último, se estudia la prohibición dentro del ordenamiento jurídico colombiano de la cadena perpetua por mandato constitucional y por disposición de tratados internacionales ratificados en Colombia, junto con el recedente jurisprudencial establecido por la Corte Constitucional y la Corte Suprema de Justicia
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