1,355 research outputs found
DWT-based Method for Partial Discharge Pattern Recognition
The new proposed method of pattern recognition is based on the application of Multiresolution Signal Decomposition (MSD) technique of wavelet transform. This technique has shown interesting properties in capturing the embedded horizontal, vertical and diagonal variations within an image obtained from the PD pattern in a separable form. This feature has been exploited to identify in the PD patterns MSD, relative at various family of PD sources, some detail images typical of a single discharge phenomenon. The classification of a generic PD phenomenon is feasible through a comparison between its detail images and the detail images typical of a single discharge phenomenon. Tests have been performed on specimens having single defects. The obtained results prove that the proposed improved classification methods is quite efficient and accurate.
[DOI: 10.1685 / CSC06133] About DO
Effects of fault transmissivity on the potential of fault reactivation and induced seismicity : Implications for understanding induced seismicity at Pohang EGS
Funding Information: The project leading to part of the results in this article received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 691728 .Peer reviewedPublisher PD
Time Evolution of Partial Discharges in a Dielectric Subjected to the DC Periodic Voltage
Partial discharge (PD) detection can be considered one of the most useful tools for assessing the insulation conditions of the power apparatus in high-voltage systems. Under AC conditions, this analysis is widely employed in online and offline tests, such as type tests or commissioning, and can be carried out by applying the phase-resolved PD (PRPD) method, since the patterns can give information about the defect classification. Under DC voltages, the classic pattern recognition method cannot be performed, and the measurements show complexities related to the nature of the phenomena. For this reason, to date, a standard for PD measurements under DC does not exist. In previous papers, a new method for PD detection under DC stress voltages has been proposed by the authors. It is based on the application of a direct current periodic (DCP) waveform useful in obtaining PRPD patterns. The dependence of partial discharge inception voltage (PDIV) and PD repetition rate (PDRR) on the \u3b4 shape parameter of the DCP for different materials, as well as the capability to recognize different discharge phenomena, provided valid indications on the behavior of PD in the transition from AC to DC. The aim of this paper is to evaluate the time dependence of PD occurring in a dielectric by applying the DCP waveform. In our previous studies, the investigations were focused on the PD behavior under different values of the DC voltage periodic part. In another work, the DCP waveform with both positive and negative polarity was applied to several dielectric materials. In the proposed work, instead, the DCP waveform is applied for a long time in order to observe its effect on the PD behavior for 72 h. In this way, due to the space charge accumulation phenomenon, the aging effect, also due to the space charge accumulation phenomenon, is evaluated. The methodological approach was to acquire PRPD patterns over time and evaluate their trends in comparison with the sinusoidal case. The experimental results show that, with a DCP waveform having \u3b4 = 0.6, the aging effect similar to that provided by pure DC stress is observed, while the acquired PRPD patterns are easily interpretated, as in the AC case
Adaptive Path Planning for Depth Constrained Bathymetric Mapping with an Autonomous Surface Vessel
This paper describes the design, implementation and testing of a suite of
algorithms to enable depth constrained autonomous bathymetric (underwater
topography) mapping by an Autonomous Surface Vessel (ASV). Given a target depth
and a bounding polygon, the ASV will find and follow the intersection of the
bounding polygon and the depth contour as modeled online with a Gaussian
Process (GP). This intersection, once mapped, will then be used as a boundary
within which a path will be planned for coverage to build a map of the
Bathymetry. Methods for sequential updates to GP's are described allowing
online fitting, prediction and hyper-parameter optimisation on a small embedded
PC. New algorithms are introduced for the partitioning of convex polygons to
allow efficient path planning for coverage. These algorithms are tested both in
simulation and in the field with a small twin hull differential thrust vessel
built for the task.Comment: 21 pages, 9 Figures, 1 Table. Submitted to The Journal of Field
Robotic
Fórmulas de inmunonutrición enteral en la cirugía del cáncer de cabeza y cuello: Una revisión sitemática
Introduction: Significant malnutrition exists in a high
percentage of patients with head and neck cancer. Malnutrition
is associated with defects in immune function that
may impair the host response to malignancy. Malnutrition
and immunosupression make patients highly susceptible
to postoperative infections and complications.
Objectives: Some studies of patients receiving immunonutrition
in the perioperative period in head and neck
cancer have shown beneficial effects on clinical outcome
and inmune status. The authors carried out a systematic
review of randomised control trials to determine whether
perioperative immunonutrition has a role in the treatment
of head and neck cancer.
Methods: 14 trials of polymeric nutritional supplementation
with immunonutrition were identified. Two studies
compared two types of immunonutrition.
Results: A reduction in the length of postoperative
hospital stay was seen in some trials, but the reason for
this reduction is not clear. Some studides showed statistical
differences with less complications in arginineenhanced
group and also showed a significant decrease of
fistula complications in patients treated with a high arginine
dose enhanced formula, if compared with a medium
dose of arginine.
Conclussion: Those planning future studies face
challenges. A suitable powered clinical trial is required
before firm recommendations can be made on the use of
immunonutrition in head and neck cancer patients postoperativelyIntroducción: Un alto porcentaje de pacientes con cáncer
de cabeza y cuello presentan un importante grado de
malnutrición. Esta malnutrición está asociada defectos de
la función inmune. Tanto la malnutrición como la inmunosupresión
hacen a estos pacientes susceptibles de padecer
complicaciones infecciosas en el postoperatorio.
Objetivos: Algunos trabajos de pacientes que han recibido
inmunonutrición en el postoperatorio de cirugía por
cáncer de cabeza y cuello han mostrado un efecto beneficioso
en la evolución clínica y el estado inmune. Los autores
han llevado a cabo una revisión sistemática de los
ensayos clínicos realizados hasta la fecha, para determinar
el papel que tiene la inmunonutrición enteral postoperatoria
en el tratamiento del cáncer de cabeza y cuello.
Métodos: Se identificaron 14 trabajos en los que se
habían utilizado fórmulas de inmunonutrición. Dos trabajos
compararon dos tipos de inmunonutrición. Resultados:
En algunos trabajos se observó una disminución en
los días de estancia hospitalaria, aunque la razón para
ello no está clara. Algunos estudios mostraron diferencias
significativas con menos complicaciones en los grupos que
recibieron nutriciones enriquecidas, presentando una
disminución significativa en el número de fístulas en
pacientes tratados con nutriciones con altas dosis de arginina,
si se compara con una nutrición con una dosis media
de arginina.
Conclusión: Los futuros trabajos presentan retos. Es
necesario un ensayo clínico extenso, para poder realizar
recomendaciones firmes sobre el uso de la inmunonutrición
en el postoperatorio de pacientes intervenidos de
cáncer de cabeza y cuell
Epidemiology of distal radius fractures: a detailed survey on a large sample of patients in a suburban area
Background: Literature lacks data on correlations between epidemiology and clinical data of patients with distal
radius fractures (DRFs).
Aim: The aim of this study was to present a detailed epidemiologic survey of a large consecutive series of patient
with DRFs.
Materials and Methods: This retrospective study included 827 consecutive patients (579 females, 248 men) who
sustained a DRFs in the last 5 years. All fractures were radiographically evaluated. DRFs were classifed according to
Association of Osteosynthesis classifcation. Data on age, gender, side, period in which fracture occurred, and fracture
mechanism were collected. Statistical analysis was performed.
Results: The patients’ mean age was 60.23 [standard deviation (SD) 16.65] years, with the left side being most frequently involved (56.1%). The mean age of females at the time of fracture was signifcantly higher than that of males.
The most frequent pattern of fracture was the complete articular fracture (64.3%), while the most represented fracture
type was 2R3A2.2 (21.5%). Regarding the period in which the fracture occurred, 305 DRFs (37.5%) were observed in
the warmer months and 272 (33.4%) in the colder months. Low-energy trauma occurring outside home was found to
be the major cause of DRF throughout the year.
In both genders, trauma mechanism 2 was more frequent (59.4% F; 31.9% M; p<0.01).
A bimodal distribution of fracture mechanisms was found in males when considering the patient’s age with a highenergy mechanism of fracture (3 and 4), identifed in 21% (n=52) of males aged 18–45 years, and a low-energy
mechanism (1 and 2) was observed in 39.9% (n=99) of males aged>45 years. A signifcant correlation between all
trauma mechanisms (from 1 to 6) and diferent fracture patterns (complete, partial, and extraarticular) was found
(p value<0.001). The mean age of patients with extraarticular fractures (mean age 61.75 years; SD 18.18 years) was
higher than that of those with complete (mean age 59.84 years; SD 15.67 years) and partial fractures (mean age
55.26 years; SD 18.31 years). Furthermore, considering diferent fracture patterns and patient age groups, a statistically
signifcant diference was found (p<0.001).
Conclusions: DRFs have a higher prevalence in females, an increase in incidence with older age, and no seasonal
predisposition. Low-energy trauma occurring at home is the main cause of fracture among younger males sustaining fractures after sports trauma; Complete articular is the most frequent fracture pattern, while 2R3A2.2 is most frequent
fracture type.
Level of evidence: Level IV; case series; descriptive epidemiology stud
Modifying the Diabetes Prevention Program to Adolescents in a School Setting: A Feasibility Study
The growing epidemic of overweight children has led to a higher prevalence of youth being diagnosed with diabetes, particularly type 2 diabetes. The current study modified the Diabetes Prevention Program (DPP) for use with 7th–10th graders in a school setting. The DPP is an evidence-based lifestyle intervention program that has been translated successfully in various adult settings. Yet the feasibility of modifying the DPP for use with middle and high school students has not been documented. A multidisciplinary university research team collaborated with a local charter school to include a modified DPP as part of the curriculum for one semester. Pre- and posttests included food knowledge, health locus of control, BMI, and performance on the 12-minute Cooper walk/run test. Findings suggest tentatively that the modified DPP was successful at increasing food knowledge and awareness of more rigorous physical activity as well as their association to improved health outcomes. Equally as important, results demonstrate that it is feasible to conduct interventions targeting healthy weight among adolescents in school-based settings by incorporating them in the curriculum.</jats:p
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