scholarly journals Assessment of wavelet-based spatial verification by means of a stochastic precipitation model (wv_verif v0.1.0)

2019 ◽  
Author(s):  
Sebastian Buschow ◽  
Jakiw Pidstrigach ◽  
Petra Friederichs
Keyword(s):  
Stochastic Model ◽  
High Dimensional ◽  
Feature Location ◽  
Test Bed ◽  
Spatial Correlations ◽  
Naked Eye ◽  
Verification Tool ◽  
Spatial Verification ◽  
Wavelet Transformations

Abstract. The quality of precipitation forecasts is difficult to evaluate objectively because images with disjoint features surrounded by zero intensities cannot easily be compared pixel by pixel: Any displacement between observed and predicted field is punished twice, generally leading to better marks for coarser models. To answer the question whether a highly resolved model truly delivers an improved representation of precipitation processes, alternative tools are thus needed. Wavelet transformations can be used to summarize high-dimensional data in a few numbers which characterize the field's texture. A comparison of the transformed fields judges models solely based on their ability to predict spatial correlations. The fidelity of the forecast's overall structure is thus investigated separately from potential errors in feature location. This study introduces several new wavelet based structure-scores for the verification of deterministic as well as ensemble predictions. Their properties are rigorously tested in an idealized setting: A recently developed stochastic model for precipitation extremes generates realistic pairs of synthetic observations and forecasts with prespecified spatial correlations. The wavelet-scores are found to react sensitively to differences in structural properties, meaning that the objectively best forecast can be determined even in cases where this task is difficult to accomplish by naked eye. Random rain fields prove to be a useful test-bed for any verification tool that aims for an assessment of structure.

scholarly journals Assessment of wavelet-based spatial verification by means of a stochastic precipitation model (wv_verif v0.1.0)

2019 ◽  
Vol 12 (8) ◽  
pp. 3401-3418 ◽  
Author(s):  
Sebastian Buschow ◽  
Jakiw Pidstrigach ◽  
Petra Friederichs
Keyword(s):  
High Dimensional ◽  
Spatial Structures ◽  
Feature Location ◽  
Test Bed ◽  
Spatial Correlations ◽  
Naked Eye ◽  
Verification Tool ◽  
Spatial Verification ◽  
Wavelet Transformations

Abstract. The quality of precipitation forecasts is difficult to evaluate objectively because images with disjointed features surrounded by zero intensities cannot easily be compared pixel by pixel: any displacement between observed and predicted fields is punished twice, generally leading to better marks for coarser models. To answer the question of whether a highly resolved model truly delivers an improved representation of precipitation processes, alternative tools are thus needed. Wavelet transformations can be used to summarize high-dimensional data in a few numbers which characterize the field's texture. A comparison of the transformed fields judges models solely based on their ability to predict spatial structures. The fidelity of the forecast's overall pattern is thus investigated separately from potential errors in feature location. This study introduces several new wavelet-based structure scores for the verification of deterministic as well as ensemble predictions. Their properties are rigorously tested in an idealized setting: a recently developed stochastic model for precipitation extremes generates realistic pairs of synthetic observations and forecasts with prespecified spatial correlations. The wavelet scores are found to react sensitively to differences in structural properties, meaning that the objectively best forecast can be determined even in cases where this task is difficult to accomplish by naked eye. Random rain fields prove to be a useful test bed for any verification tool that aims for an assessment of structure.

Research on the Reliability of Box for Gear Test Bed

2011 ◽  
Vol 121-126 ◽  
pp. 1744-1748
Author(s):  
Xiang Yang Jin ◽  
Tie Feng Zhang ◽  
Li Li Zhao ◽  
He Teng Wang ◽  
Xiang Yi Guan
Keyword(s):  
Power Flow ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Design Parameters ◽  
The Finite Element Method ◽  
Test Bed ◽  
Kinematics Simulation ◽  
Beveloid Gears ◽  
Overall Performance

To determine the efficiency, load-bearing capacity and fatigue life of beveloid gears with intersecting axes, we design a mechanical gear test bed with closed power flow. To test the quality of its structure and predict its overall performance, we establish a three-dimensional solid model for various components based on the design parameters and adopt the technology of virtual prototyping simulation to conduct kinematics simulation on it. Then observe and verify the interactive kinematic situation of each component. Moreover, the finite element method is also utilized to carry out structural mechanics and dynamics analysis on some key components. The results indicate that the test bed can achieve the desired functionality, and the static and dynamic performance of some key components can also satisfy us.

A Rank Order of Eateries: A Chicago Stochastic Model

1974 ◽  
Vol 7 (02) ◽  
pp. 165-174
Author(s):  
Donald H. Haider
Keyword(s):  
New York ◽  
Stochastic Model ◽  
Rank Order ◽  
The Many ◽  
New Yorkers

.... The hands of men took hold and tugged And the breaths of men went into the junk And the junk stood up into skyscrapers and asked Who am I? Am I a city?Carl Sandburg-“The Windy City”Robert Merriam, picking up where his father left off, once indicated that it would take 50 years for an aroused citizenry to root out corruption in Chicago. It has taken at least that long to upgrade Chicago's restaurants. Several decades ago, top gourmet societies labelled Chicago a “gastronomic wasteland.” Among the many old clichés and modern prejudices that the Windy City is constantly seeking to outlive is the quality of its restaurants. New Yorkers, of course, will not let old myths die. Gail Green,New York Magazinegalloping gourmet, recently went away from Chicago dubbing its restaurants the “Big Potato” — homely and solid, mealy and bland. Chicago epicureans responded by a whirlwind tour of the Gotham Town's “Best and Most Delectable,” writing devastating critiques of New York's much overrated eating places. If one can transcend these diatribes and gastronomic polemics, you will find Chicago to be as good a dining town as there is in the U.S.A. — variety, service, and prices.

scholarly journals A Secured Load Mitigation and Distribution Scheme for Securing SIP Server

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Vennila Ganesan ◽  
Manikandan MSK
Keyword(s):  
Load Distribution ◽  
Test Bed ◽  
Heavy Load ◽  
Server Selection ◽  
Distribution Scheme ◽  
The Mean ◽  
Sip Server ◽  
Second Tier ◽  
Termination Time

Managing the performance of the Session Initiation Protocol (SIP) server under heavy load conditions is a critical task in a Voice over Internet Protocol (VoIP) network. In this paper, a two-tier model is proposed for the security, load mitigation, and distribution issues of the SIP server. In the first tier, the proposed handler segregates and drops the malicious traffic. The second tier provides a uniform load of distribution, using the least session termination time (LSTT) algorithm. Besides, the mean session termination time is minimized by reducing the waiting time of the SIP messages. Efficiency of the LSTT algorithm is evaluated through the experimental test bed by considering with and without a handler. The experimental results establish that the proposed two-tier model improves the throughput and the CPU utilization. It also reduces the response time and error rate while preserving the quality of multimedia session delivery. This two-tier model provides robust security, dynamic load distribution, appropriate server selection, and session synchronization.

The Muscle Myogram as a Control Signal for Use in Powered Limb Orthosis

2006 ◽  
Author(s):  
M. Antonelli ◽  
P. Beomonte Zobel ◽  
J. Giacomin
Keyword(s):  
Lower Limb ◽  
Assistive Device ◽  
Sitting Position ◽  
Test Bed ◽  
Disabled People ◽  
Test Protocol ◽  
Prosthetic Devices ◽  
Specific Device ◽  
Definition Of

The choice of the command technique to be used in orthotic and prosthetic devices is very critical for the acceptance and, finally, the success of the specific device. Many variables influence this choice: the general characteristics of the signal, the quality of the correlation between signal and specific actions of the user and the algorithm that is derived, the acceptance of the technique, as applied to the specific device, from the user, etc. Among the command techniques, MMG signal seems to be promising to command an assistive device. In this paper a test protocol for studying MMG signal, to investigate the prospective for its use as a command technique of a powered lower limb orthosis capable of raising elderly and disabled people from the sitting position, is proposed. The definition of the test protocol, including the description of the test bed and the sensors application, is presented. Finally, the experimental results are showed and discussed.

scholarly journals Impacts of stochastic models on real-time 3D UAV mapping

2014 ◽  
Vol XL-1 ◽  
pp. 35-44
Author(s):  
M. Alqurashi ◽  
J. Wang
Keyword(s):  
Stochastic Model ◽  
Real Time ◽  
Stochastic Models ◽  
Feature Matching ◽  
Critical Role ◽  
Image Feature ◽  
Mapping Process ◽  
Camera Orientation ◽  
Camera Position

In UAV mapping using direct geo-referencing, the formation of stochastic model generally takes into the account the different types of measurements required to estimate the 3D coordinates of the feature points. Such measurements include image tie point coordinate measurements, camera position measurements and camera orientation measurements. In the commonly used stochastic model, it is commonly assumed that all tie point measurements have the same variance. In fact, these assumptions are not always realistic and thus, can lead to biased 3D feature coordinates. Tie point measurements for different image feature objects may not have the same accuracy due to the facts that the geometric distribution of features, particularly their feature matching conditions are different. More importantly, the accuracies of the geo-referencing measurements should also be considered into the mapping process. In this paper, impacts of typical stochastic models on the UAV mapping are investigated. It has been demonstrated that the quality of the geo-referencing measurements plays a critical role in real-time UAV mapping scenarios.

scholarly journals 195 The Application of Radiomics in Laryngeal Cancer: The Forgotten Cohort

2021 ◽  
Vol 108 (Supplement_6) ◽  
Author(s):  
A Rajgor ◽  
A McQueen ◽  
T Ali ◽  
E Aboagye ◽  
B Obara ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Head And Neck ◽  
Laryngeal Cancer ◽  
Prognostic Value ◽  
Head And Neck Cancers ◽  
High Dimensional ◽  
Naked Eye ◽  
Online Databases ◽  
Novel Method

Abstract Background Radiomics is a novel method of extracting data from medical images that is difficult to visualise through the naked eye. This technique transforms digital images that hold information on pathology into high-dimensional-data for analysis. Radiomics has the potential to enhance laryngeal cancer care and to date, has shown promise in various other specialties. Aim The aim of this review is to summarise the applications of this technique to laryngeal cancer and potential future benefits. Method A comprehensive systematic review-informed search of the MEDLINE and EMBASE online databases was undertaken. Keywords ‘laryngeal cancer’ OR ‘larynx’ OR ‘larynx cancer’ OR ‘head and neck cancer’ were combined with ‘radiomic’ OR ‘signature’ OR ‘machine learning’ OR ‘artificial intelligence’. Additional articles were obtained from bibliographies using the ‘snowball method’. Results Seventeen articles were identified that evaluated the role of radiomics in laryngeal cancer. Two studies affirmed the value of radiomics in improving the accuracy of staging, whilst fifteen studies highlighted the potential prognostic value of radiomics in laryngeal cancer. Twelve (of thirteen) studies incorporated an array of different head and neck cancers in the analysis and only one study assessed laryngeal cancer exclusively. Conclusions Literature to date has various limitations including, small and heterogeneous cohorts incorporating patients with head and neck cancers of distinct anatomical subsites and stages. The lack of uniform data on solely laryngeal cancer and radiomics means drawing conclusions is difficult, although these studies have affirmed its value. Further large prospective studies exclusively in laryngeal cancer are required to unlock its true potential.

Detecting Denial of Service Attacks on SIP Based Services and Proposing Solutions

2011 ◽  
pp. 145-167 ◽  
Author(s):  
Zoha Asgharian ◽  
Hassan Asgharian ◽  
Ahmad Akbari ◽  
Bijan Raahemi
Keyword(s):  
Denial Of Service ◽  
Denial Of Service Attacks ◽  
False Alarms ◽  
Test Bed ◽  
Multimedia Services ◽  
Detection Rates ◽  
Signaling Protocol ◽  
Detection Techniques ◽  
Set Up

One of the main goals of employing Next Generation Networks (NGN) is an integrated access to the multimedia services like Voice over IP (VoIP), and IPTV. The primary signaling protocol in these multimedia services is Session Initiation Protocol (SIP). This protocol, however, is vulnerable to attacks, which may impact the Quality of Service (QoS), which is an important feature in NGN. One of the most frequent attacks is Denial of Service (DoS) attack, which is generated easily, but its detection is not trivial. In this chapter, a framework is proposed to detect Denial of Service attacks and a few other forms of intrusions, and then we react accordingly. The proposed detection engine combines the specification- and anomaly-based intrusion detection techniques. The authors set up a test-bed and generate a labeled dataset. The traffic generated for the test-bed is composed of two types of SIP packets: attack and normal. They then record the detection rates and false alarms based on the labeled dataset. The experimental results demonstrate that the proposed approach can successfully detect intruders and limit their accesses. The results also confirm that the framework is scalable and robust.

Design by a CBIR System Supporting High Level Concepts

2011 ◽  
pp. 259-268
Author(s):  
M. V. Ramakrishna ◽  
S. Nepal ◽  
S. Sumanasekara ◽  
S. M.M. Tahaghoghi
Keyword(s):  
Similarity Measures ◽  
Linear Mapping ◽  
Content Based Image Retrieval ◽  
High Dimensional ◽  
Test Bed ◽  
Development Activity ◽  
Indexing Structure ◽  
Level Data ◽  
High Dimensional Indexing ◽  
High Level

Content Based Image Retrieval (CBIR) systems that are able to “retrieve images of Clinton with Lewinsky” are unrealistic at present. However, this area has seen much research and development activity since IBM’s QBIC announcement in 1994. The CHITRA CBIR system under development at the RMIT and Monash Universities, addresses the need for a test bed system. Users can dynamically incorporate new features and similarity measures in to the system, enabling it to act as a testbed for CBIR research. The system uses a 4-level data model we have developed and supports definition and querying of high level concepts such as MOUNTAIN and SUNSET. These advanced capabilities are supported by a powerful graphical query mechanism and a high-dimensional indexing structure based on linear mapping. In this paper we describe the design of the system, our contributions to the state of the art and provide some implementation details.

scholarly journals CyTOFmerge: integrating mass cytometry data across multiple panels

2019 ◽  
Vol 35 (20) ◽  
pp. 4063-4071 ◽  
Author(s):  
Tamim Abdelaal ◽  
Thomas Höllt ◽  
Vincent van Unen ◽  
Boudewijn P F Lelieveldt ◽  
Frits Koning ◽  
...  
Keyword(s):  
Single Cell ◽  
Biological Sample ◽  
Supplementary Information ◽  
High Dimensional ◽  
Single Cell Level ◽  
Supplementary Data ◽  
Mass Cytometry ◽  
Cell Level ◽  
Cellular Markers

Abstract Motivation High-dimensional mass cytometry (CyTOF) allows the simultaneous measurement of multiple cellular markers at single-cell level, providing a comprehensive view of cell compositions. However, the power of CyTOF to explore the full heterogeneity of a biological sample at the single-cell level is currently limited by the number of markers measured simultaneously on a single panel. Results To extend the number of markers per cell, we propose an in silico method to integrate CyTOF datasets measured using multiple panels that share a set of markers. Additionally, we present an approach to select the most informative markers from an existing CyTOF dataset to be used as a shared marker set between panels. We demonstrate the feasibility of our methods by evaluating the quality of clustering and neighborhood preservation of the integrated dataset, on two public CyTOF datasets. We illustrate that by computationally extending the number of markers we can further untangle the heterogeneity of mass cytometry data, including rare cell-population detection. Availability and implementation Implementation is available on GitHub (https://github.com/tabdelaal/CyTOFmerge). Supplementary information Supplementary data are available at Bioinformatics online.

Sign in / Sign up

Export Citation Format

Share Document