Data-Driven Fault Detection in a Thermocouple Network Using Neighboring Redundancy, XGBoost Classifier, and Up–Down Counter

Fault detection and isolation (FDI) is of great interest for the control community since it can drive improved performance in a system by allowing predictive maintenance/repairing and catering for improved operational safety. FDI in large-scale smelting furnaces presents several challenges, as it requires the understanding of complex thermal and chemical reactions occurring inside the structure. Furthermore, the impossibility of having full operational information about the process makes the use of model-based methods very complex or unfeasible. This article introduces a methodology to develop a data-driven FDI system for the detection of incipient and intermittent failures in a network made out of 322 thermocouples located on the shell of the furnace. Statistical metrics over fault counter time windows (FTCWs) were used to identify different types of sensor failures, which led to establishing a baseline of known failure events and to create a dataset to train the machine learning (ML) classification models. A data-driven approach was proposed based on the sensors’ physical (neighboring) redundancy, which led to some type of physical redundancy. A postprocessing stage was used to stabilize the model’s response in time, determining that the proposed FDI system successfully detects faults while reducing reported false negatives.<br/

Methyl 5a-acetoxy­methyl-3-isopropyl-8-methyl-1,2,3,3a,4,5,5a,6,7,10,10a,10b-dodeca­hydro-7,10-endo-epidioxy­cylohepta­[e]indene-3a-carboxyl­ate

The mol­ecule of the title compound, C23H34O6, is built up from three fused carbocycles, one five-membered, one six-membered and one seven-membered. The five-membered ring has an envelope conformation, whereas the six-membered ring has a perfect chair conformation and the seven-membered ring has a boat conformation. Intra­molecular C—H⋯O hydrogen bonds together with van der Waals inter­actions stabilize the mol­ecular conformation

Modeling determinants of tourism demand in Colombia

Purpose – This paper estimates the determinants of international tourist arrivals to Colombia from 1995 to 2014. Design – Tourist demand is related to interlinking relationships between origins and destinations. The international movement of travelers has grown exponentially in recent decades, and these dynamics have affected Colombia as well. Methodology/Approach – We propose a generalized linear mixed model, with a consideration of factors from the theory of consumer choice and those approached from the perspective of new economic geography. Findings – Apart from purchasing power and institutional factors as facilitators of travel, we found that general aspects of the country (such as language and geographical proximity) directly affect the flow of visitors, whereas exchange differences and physical distance reduce tourist attraction. Originality of the research – Estimation of tourist flows will serve as a diagnostic and planning tool for developing proposals of tourism attractiveness related to different environment. Keywords tourism demand, tourist flows, generalized linear mixed model, developing countrie

Las fronteras invisibles en las comunas 16 y 70 de Medellín (2008-2013): poder, territorio y resistencia

En este artículo se analiza la forma en que se desarrolló el fenómeno de las fronteras invisibles en las comunas 16 y 70 de Medellín entre los años 2008 y 2013, momento en que se agudizó el conflicto armado urbano en la ciudad. Con ese objetivo se entrevistaron actores sociales, institucionales y académicos que experimentaron esos enfrentamientos violentos desde diversas posiciones. Estas voces se analizaron a partir de discusiones teóricas en torno al poder, el territorio y la resistencia, que permitieron explicar la territorialización de una violencia que devino en la imposición de barreras imaginarias sobre la población

Quiste del uraco abscedado. Presentación de un caso

The urachus is a tubular structure located in the infraumbilical midline extending from the anterior portion of the bladder dome to the umbilicus. The persistence of some parts of the urachus will lead to congenital anomalies derived from it, being the cyst the most common one. The urachal cysts are small and remain unnoticed until some complications present clinical symptoms, sepsis among them. A 64 year old patient complaining of a pain in the hypogastrium for 15 days is presented. The patient had a palpable tumor mass about 10cm in diameter. An ultrasonography of the abdomen and of the soft parts was carried out and an infected urachal cyst was diagnosed. An emergency total resection was carried out and the patient evolved satisfactorily being discharged the seventh day of the postoperative.El uraco es una estructura tubular localizada en la línea media infraumbilical que se extiende desde la porción anterior de la cúpula vesical hasta el ombligo; la persistencia de alguna de las partes del uraco dará lugar a las anomalías congénitas derivadas de él, entre las que el quiste es la más frecuente. Los quistes uracales son pequeños y permanecen ocultos hasta que sus complicaciones, dentro de ellas la sepsis, debutan clínicamente. Se presentó un paciente de 64 años de edad que desde hace 15 días refería dolor en el hipogastrio, con una masa tumoral palpable de aproximadamente 10cm. de diámetro; se le realizó un ultrasonido abdominal y de partes blandas; se le diagnosticó un quiste uracal infectado; se procedió a resecarlo quirúrgicamente de urgencia y se le realizó exéresis total del mismo; evolucionó satisfactoriamente y egresó al 7mo día del postoperatorio

TRIBUNAL ARBITRAL DE REDES TECNICAS E INSTALACIONES S. EN C. VS. ACTIVIDADES DE INSTALACIONES Y SERVICIOS COBRA S.A. y COLOMBIA TELECOMUNICACIONES S.A. E.S.P.

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Absceso esplénico. Presentación de un paciente

The splenic abscess is not a common illness. There are less than 700 cases described in medical literature since the beginning of the 20th century. The causes described are the contiguous infections at any level of the abdominal cavity, as well as the hematogenic way. Eighty percent of them take place or coincide with systemic sepsis such as: otitis, mastoiditis, peritonsillar abscesses, suppurative parotiditis, cutaneous infections, lung abscesses, appendicitis, diverticulitis, cholecystitis and osteomielytis. A 58 year old female patient, who was admitted to hospital presenting abdominal pain in the upper hemiabdomen, a prolonged fever of 38-39 degrees Celsius and pain on deep palpation in the left hypochondrium, is presented. The patient underwent an abdominal spiral tomography and a hypodense image of 8x6cm in the lower pole of the spleen was seen; it corresponded to a splenic abscess. A splenectomy with a toilet of the splenic cavity was carried out, and a postoperative treatment was implemented. The patient evolved satisfactorily and was discharged the eighth postoperative day.El absceso esplénico es una enfermedad poco frecuente, con menos de 700 casos descritos en la literatura médica desde principios del siglo XX; sus causas son las infecciones por contigüidad a cualquier nivel de la cavidad abdominal -también se informa la vía hematógena-; el 80% de ellos ocurren o coinciden con una sepsis sistémica como: otitis, mastoiditis, abscesos periamigdalinos, parotiditis supurativas, infecciones cutáneas, abscesos pulmonares, apendicitis, diverticulitis, colecistitis y osteomielitis. Se presenta una paciente femenina de 58 años de edad que ingresó con un cuadro clínico caracterizado por dolor abdominal a nivel del hemiabdomen superior, fiebre prolongada de 38- 39ºC y dolor a la palpación profunda en hipocondrio izquierdo; se le realizó una tomografía helicoidal abdominal donde se observó una imagen hipodensa de 8x6cm en el polo inferior del bazo correspondiente a un absceso esplénico; se realizó una esplenectomía con toillette de la celda esplénica y tratamiento con antibiótico postoperatorio; evolucionó satisfactoriamente y fue egresada al octavo día

Colangitis esclerosante primaria. Presentación de un caso y revisión del tema

The patient was admitted to hospital presenting an abdominal pain localized in the epigastrium, with irradiation to the left hypochondrium and a discrete jaundice; at first it was indicative of an ischemic heart disease because of the typical electrocardiographic changes it presented. After undergoing an abdominal ultrasonography, an acute cholecystitis was diagnosed. An endoscopic retrograde cholangiopancreatography was indicated. It showed an acute cholangitis, without lithiasis in the main bile duct. An endoscopic sphincterotomy was carried out. The patient underwent an emergency cholecystectomy. It was necessary to repeat the cholangiopancreatography because of the persistent jaundice and the suspicion of sclerosing cholangitis was confirmed. The patient received antibiotic treatment (ampicillin) and steroids; his general condition improved and was discharged.Se presenta un paciente de 65 años de edad con antecedentes de hipertensión arterial y fiebre reumática que ingresa con un cuadro de dolor abdominal localizado en el epigastrio, con irradiación al hipocondrio derecho e íctero discreto que, inicialmente, fue sugestivo de una cardiopatía isquémica por presentar cambios electrocardiográficos propios de ella; se le diagnosticó una colecistitis aguda después de realizar un ultrasonido abdominal. Se indicó una colangiopancreatografía retrógrada endoscópica que demostró una colangitis aguda, sin litiasis en la vía biliar principal, y se le realizó una esfinterotomía endoscópica; se intervino de urgencia y se le efectuó una colecistectomía, posteriormente fue necesario repetir la colangiopancreatografía debido al íctero persistente y se confirmó la sospecha de colangitis esclerosante. El paciente llevó tratamiento con antibióticos (ampicillina) y esteroides, mejoró su estado general y fue egresado