Application of a Generalized Criterion: Time-of-Failure Forecast and Alert Thresholds Assessment for Landslides

2020 ◽  
pp. 283-298
Author(s):  
Alessandro Valletta ◽  
Andrea Segalini ◽  
Andrea Carri
2007 ◽  
Vol 30 (4) ◽  
pp. 59
Author(s):  
H. Carnahan ◽  
E. Hagemann ◽  
A. Dubrowski

A debate is emerging regarding the efficacy of proficiency based versus duration based training of technical skills. It is not clear whether the performance level attained at the end of practice (i.e., proficiency criteria), or the overall amount of practice performed during learning will best predict the retention of a technical clinical skill. The skill learned was the single-handed double square-knot. Forty two trainees learned the skill through video-based instruction and were divided into three groups (14 participants per group) each with a specific criterion time to tie the knot (10, 15, and 20 seconds). Practice continued until participants completed the knot within their criterion time. The total number of trials, and the overall practice time required to obtain each respective criterion were recorded during practice. Participants returned one-week later for a timed retention test consisting of one trial of the knot tying skill with no video instruction. A multiple regression analysis tested whether the amount of practice, the total practice time, or the criterion reached at the end of practice was the best predictor of the time taken to perform the skill during retention. This analysis showed that the number of practice trials was highly correlated with total practice time (r = .82, p = .01), therefore total practice time was withdrawn as a predictor variable from the subsequent analysis. The regression showed that the only significant predictor of retention performance was the criterion reached at the end of practice (p = .03). The number of practice trials was not found to significantly predict the retention performance (p = .87). The results support the notion that proficiency based training results in better retention of a technical clinical skill in comparison to duration based approaches. This provides evidence for the introduction of proficiency based educational approaches in technical skills curricula. Jowett N, LeBlanc V, Xeroulis G, MacRae H, Dubrowski A. Surgical skill acquisition with self-directed practice using computer-based video training. Am J Surg. 2007; 193(2):237-42. Gallagher AG, Ritter EM, Champion H, Higgins G, Fried MP, Moses G, Smith CD, Satava RM. Virtual reality simulation for the operating room: proficiency-based training as a paradigm shift in surgical skills training. Ann Surg. 2005; 241(2):364-72. Van Sickle KR, Ritter EM, McClusky DA, Lederman A, Baghai M, Gallagher AG, Smith CD. Attempted establishment of proficiency levels for laparoscopic performance on a national scale using simulation: the results from the 2004 SAGES Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR) learning center study. Surg Endosc. 2007; 21(1):5-10.


Author(s):  
Giulio Avanzini ◽  
David S Martínez

A procedure for evaluating the risk related to the use of unmanned aerial systems over populated areas is proposed. A nominal trajectory, planned for performing a given mission, is represented by means of motion primitives, that is segments and arcs flown in a steady-state condition. The risk of hitting a person on the ground after catastrophic failure is evaluated as a function of vehicle reliability and population density (assumed known), and position of the impact point (which depends on initial conditions at the time of failure and trajectory flown afterwards). In the deterministic case, a lethal area is introduced and the risk at each point on the ground is proportional to the amount of time spent by the point inside the lethal area. Under the assumptions of a ballistic fall, the position of the lethal area with respect to the nominal trajectory depends only on altitude and velocity at the time of failure. When the effect of navigation errors is introduced, impact points are described by a statistical impact footprint, assuming that position and velocity errors at time of failure are normally distributed with known standard deviations. The two approaches are compared for a fictitious, yet realistic, mission scenario.


1976 ◽  
Vol 49 (5) ◽  
pp. 1167-1181 ◽  
Author(s):  
A. Y. Coran ◽  
P. Hamed ◽  
L. A. Goettler

Abstract The measured elastic and strength properties of angle-ply composites of short fibers and rubber depend on test-piece geometry. In general, higher tensile moduli and strengths are obtained when plies are both thin and wide. Once the effects of test-piece geometry are taken into account, elastic properties can be calculated as functions of the properties of a single ply. Classical compliance transformation equations can be used. However, because of the invariance of shear modulus in aligned composites, the tensor transformation equations are somewhat simplified. Tensile strengths of off-axis unidirectional composite plates and balanced-angle plies can be fitted by Hill's criterion. Unidirectional composites tend to fail in the weakest mode, depending on the angle of stress, but laminating causes all principal stresses in a ply to be near their ultimate limit at the time of failure.


2021 ◽  
Author(s):  
Prakash Chaki ◽  
Takumi Ishihara ◽  
Shinya Sugiura

Postprint accepted on 30 April 2021 for publication in IEEE International Symposium on Information Theory (ISIT), 2021. (c) 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.<div>In this paper, we propose a precoded faster-than-Nyquist (FTN) signaling technique for time-domain single-carrier index modulated (IM) symbol transmission. More precisely, eigenvalue decomposition precoding is adopted for the FTN transmission of data bits modulated by single-carrier time-domain IM. While the FTN scheme increases the spectral efficiency and data rate by packing more transmit symbols per block duration than those defined in the Nyquist criterion, time-domain IM works towards the same objective while maintaining symbol sparsity. We analytically derive the constrained capacity of the proposed system. Our simulation results show that the proposed scheme has better bit error ratio (BER) performance over the conventional FTN-IM scheme, particularly for the scenario of a higher packing ratio. In the proposed scheme, $2.5$-dB performance gain is observed at the BER of 10<sup>-4</sup>, employing the packing ratio of $0.7$ and the roll-off factor of $0.5$ in a channel-uncoded scenario.<br></div>


Soundings ◽  
2020 ◽  
Vol 74 (74) ◽  
pp. 95-111
Author(s):  
Bertie Russell

Although the end of 2019 will be remembered by many as a time of failure, the last few years have also been a time of hope. This article draws lessons from the internationalist municipalist movement, and frames these experiences through the concepts of autogestion and the Right to the City. Municipalist political strategies can provide a radical re-articulation of this hope: to argue for a municipalist politics is to argue for place-based strategies that transform our relationship to our territories, with a focus on making new forms of power emerge. It is not an alternative to national and international perspectives, but rather the development of new ways of acting on these perspectives. Establishing the difference between progressive local government policy and a municipalist agenda, the article concludes by offering five propositions for the development of a municipalist coordination in one British city - Manchester.


1967 ◽  
Vol 89 (4) ◽  
pp. 824-830 ◽  
Author(s):  
S. R. Bland ◽  
R. H. Rhyne ◽  
H. B. Pierce

Vibration phenomena associated with narrow channel flow have come under study as a result of the core failure of an early nuclear rocket engine. Since the mechanism of this vibration instability was not well understood at the time of failure, an investigation of a simple system consisting of a rigid plate with two degrees of spring-restrained freedom in a two-dimensional channel has been made both experimentally and analytically. The results show a strong dependence of the flow rate required for plate oscillation on the channel width (normal to plate).


2007 ◽  
Vol 53 (180) ◽  
pp. 128-140 ◽  
Author(s):  
Jacqueline Caplan-Auerbach ◽  
Christian Huggel

AbstractSince 1994, at least six major (volume >106m3) ice and rock avalanches have occurred on Iliamna volcano, Alaska, USA. Each of the avalanches was preceded by up to 2 hours of seismicity believed to represent the initial stages of failure. Each seismic sequence begins with a series of repeating earthquakes thought to represent slip on an ice–rock interface, or between layers of ice. This stage is followed by a prolonged period of continuous ground-shaking that reflects constant slip accommodated by deformation at the glacier base. Finally the glacier fails in a large avalanche. Some of the events appear to have entrained large amounts of rock, while others comprise mostly snow and ice. Several avalanches initiated from the same source region, suggesting that this part of the volcano is particularly susceptible to failure, possibly due to the presence of nearby fumaroles. Although thermal conditions at the time of failure are not well constrained, it is likely that geothermal energy causes melting at the glacier base, promoting slip and culminating in failure. The frequent nature and predictable failure sequence of Iliamna avalanches makes the volcano an excellent laboratory for the study of ice avalanches. The prolonged nature of the seismic signal suggests that warning may one day be given for similar events occurring in populated regions.


1994 ◽  
Vol 31 (6) ◽  
pp. 1015-1021 ◽  
Author(s):  
Azm S. Al-Homoud ◽  
Ahmad B. Tal ◽  
Abdallah I. Husein (Malkawi)

This paper includes a summary of a geotechnical investigation of an embankment site at station 47 + 300 along the Irbid–Amman Highway in Jordan. The embankment suffered instability problems. This study includes geological and geotechnical mapping of the study area as well as determination of the engineering properties of the various materials encountered at the site.Stability analysis is carried out for the original embankment to explain the failure mechanism, assess the condition at the time of failure, and evaluate the soil parameters for use in stability analysis of remedial measures. Stability analysis is carried out for remedial works. Recommendations are suggested to stabilize the sliding area and to repair the road traversing this landslide zone. Key words : slope stability, embankment, remediation.


2009 ◽  
Vol 25 (11) ◽  
pp. 1179-1185 ◽  
Author(s):  
Lakshmi Rajesh ◽  
Ramesh Karunaianantham ◽  
Paranji R. Narayanan ◽  
Soumya Swaminathan

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