Modal Identification of Multi-Degree-of-Freedom Mechanical Systems Endowed With Geometric Nonlinearities

2005 ◽  
Author(s):  
R. Camillacci ◽  
C. Valente ◽  
F. Brancaleoni
Keyword(s):  
Mechanical Characteristics ◽  
Modal Identification ◽  
Laboratory System ◽  
Identification Procedure ◽  
Functional Relationships ◽  
Linear Behavior ◽  
Physical Laboratory ◽  
Set Up ◽  
Free Vibration Response ◽  
Different Levels

An identification procedure for a sample class of mechanical system exhibiting non-linear behavior is presented and validated experimentally. The proposed procedure operates on the free-vibration response of the system and is able not only to extract the time-depended modal parameters, but also to identify the functional relationships between modal frequencies and modal amplitudes of oscillation. These relationships depend just on the mechanical characteristics of the system and thus, they characterize entirely the dynamic behavior. An experimental validation of the procedure performed on a physical laboratory system is presented and discussed. The experimental set-up was designed in order to allow for different configurations and hence for different levels of nonlinearity. The comparison between the identified results and the results of a proper analytical model of the system allows for highlighting the sensibility and effectiveness of the proposed procedure.

scholarly journals Effects of disk tillage on soil condition, crop yield and weed infestation

2011 ◽  
Vol 48 (No. 1) ◽  
pp. 20-26
Author(s):  
M. Birkás ◽  
T. Szalai ◽  
C. Gyuricza ◽  
M. Gecse ◽  
K. Bordás
Keyword(s):  
Winter Wheat ◽  
Crop Yield ◽  
Field Experiments ◽  
Soil Layer ◽  
Soil Condition ◽  
Perennial Weeds ◽  
Weed Infestation ◽  
Set Up ◽  
Different Levels

This research was instigated by the fact that during the last decade annually repeated shallow disk tillage on the same field became frequent practice in Hungary. In order to study the changes of soil condition associated with disk tillage and to assess it is consequences, long-term tillage field experiments with different levels of nutrients were set up in 1991 (A) and in 1994 (B) on Chromic Luvisol at Gödöllö. The effects of disk tillage (D) and disk tillage combined with loosening (LD) on soil condition, on yield of maize and winter wheat, and on weed infestation were examined. The evaluation of soil condition measured by cone index and bulk density indicated that use of disking annually resulted in a dense soil layer below the disking depth (diskpan-compaction). It was found, that soil condition deteriorated by diskpan-compaction decreased the yield of maize significantly by 20 and 42% (w/w), and that of wheat by 13 and 15% (w/w) when compared to soils with no diskpan-compaction. Averaged over seven years, and three fertilizer levels, the cover % of the total, grass and perennial weeds on loosened soils were 73, 69 and 65% of soils contained diskpan-compaction.

scholarly journals Integration of various scales for measurement of insomnia

2021 ◽  
pp. 263208432110100
Author(s):  
Satyendra Nath Chakrabartty
Keyword(s):  
Test Scores ◽  
Data Driven ◽  
Weighted Sum ◽  
Future Studies ◽  
Normal Probability ◽  
Equivalent Test ◽  
Item Scores ◽  
Using Data ◽  
Set Up ◽  
Different Levels

Background Scales for evaluating insomnia differ in number of items, response format, and result in different scores distributions and score ranges and may not facilitate meaningful comparisons. Objectives Transform ordinal item-scores of three scales of insomnia to continuous, equidistant, monotonic, normally distributed scores, avoiding limitations of summative scoring of Likert scales. Methods Equidistant item-scores by weighted sum using data-driven weights to different levels of different items, considering cell frequencies of Item-Levels matrix, followed by normalization and conversion to [1, 10]. Equivalent test-scores (as sum of transformed item- scores) for a pair of scales were found by Normal Probability curves. Empirical illustration given. Results Transformed test-scores are continuous, monotonic and followed Normal distribution with no outliers and tied scores. Such test-scores facilitate ranking, better classification and meaningful comparison of scales of different lengths and formats and finding equivalent score combinations of two scales. For a given value of transformed test-score of a scale, easy alternate method avoiding integration proposed to find equivalent scores of another scales. Equivalent scores of scales help to relate various cut-off scores of different scales and uniformity in interpretations. Integration of various scales of insomnia is achieved by finding one-to-one correspondence among the equivalent score of various scales with correlation over 0.99 Conclusion Resultant test-scores facilitated undertaking analysis in parametric set up. Considering the theoretical advantages including meaningfulness of operations, better comparison, use of such method of transforming scores of Likert items/test is recommended test and items, Future studies were suggested.

scholarly journals Chitosan Micro-Grooved Membranes with Increased Asymmetry for the Improvement of the Schwann Cell Response in Nerve Regeneration

2021 ◽  
Vol 22 (15) ◽  
pp. 7901
Author(s):  
Luca Scaccini ◽  
Roberta Mezzena ◽  
Alessia De Masi ◽  
Mariacristina Gagliardi ◽  
Giovanna Gambarotta ◽  
...  
Keyword(s):  
Schwann Cell ◽  
Nerve Regeneration ◽  
High Fidelity ◽  
Solvent Casting ◽  
Peripheral Nerve Injuries ◽  
Cell Shaping ◽  
Micro Pattern ◽  
Chitosan Scaffolds ◽  
Set Up ◽  
Different Levels

Peripheral nerve injuries are a common condition in which a nerve is damaged, affecting more than one million people every year. There are still no efficient therapeutic treatments for these injuries. Artificial scaffolds can offer new opportunities for nerve regeneration applications; in this framework, chitosan is emerging as a promising biomaterial. Here, we set up a simple and effective method for the production of micro-structured chitosan films by solvent casting, with high fidelity in the micro-pattern reproducibility. Three types of chitosan directional micro-grooved patterns, presenting different levels of symmetricity, were developed for application in nerve regenerative medicine: gratings (GR), isosceles triangles (ISO) and scalene triangles (SCA). The directional patterns were tested with a Schwann cell line. The most asymmetric topography (SCA), although it polarized the cell shaping less efficiently, promoted higher cell proliferation and a faster cell migration, both individually and collectively, with a higher directional persistence of motion. Overall, the use of micro-structured asymmetrical directional topographies may be exploited to enhance the nerve regeneration process mediated by chitosan scaffolds.

User identification across online social networks in practice: Pitfalls and solutions

2016 ◽  
Vol 44 (3) ◽  
pp. 377-391 ◽  
Author(s):  
Azadeh Esfandyari ◽  
Matteo Zignani ◽  
Sabrina Gaito ◽  
Gian Paolo Rossi
Keyword(s):  
Social Networks ◽  
Online Social Networks ◽  
Full Range ◽  
Application Programming Interface ◽  
User Identification ◽  
Application Programming ◽  
Test Sets ◽  
Set Up ◽  
Different Levels ◽  
Programming Interface

To take advantage of the full range of services that online social networks (OSNs) offer, people commonly open several accounts on diverse OSNs where they leave lots of different types of profile information. The integration of these pieces of information from various sources can be achieved by identifying individuals across social networks. In this article, we address the problem of user identification by treating it as a classification task. Relying on common public attributes available through the official application programming interface (API) of social networks, we propose different methods for building negative instances that go beyond usual random selection so as to investigate the effectiveness of each method in training the classifier. Two test sets with different levels of discrimination are set up to evaluate the robustness of our different classifiers. The effectiveness of the approach is measured in real conditions by matching profiles gathered from Google+, Facebook and Twitter.

scholarly journals A Cognitive Approach to EkeGusii Pop Songs

2018 ◽  
Vol 9 (3) ◽  
pp. 166
Author(s):  
Victor Ondara Ntabo ◽  
Moses Gatambuki Gathigia ◽  
Naom Moraa Nyarigoti
Keyword(s):  
Conceptual Metaphor ◽  
Review Of Literature ◽  
Cognitive Approach ◽  
Conceptual Metaphor Theory ◽  
Identification Procedure ◽  
Metaphor Theory ◽  
Great Chain Of Being ◽  
Folk Conception ◽  
Different Levels

A review of literature on pop songs reveals that composers use metaphors to communicate their feelings. In particular, the meaning of the metaphors in EkeGusii pop songs needs to be interpreted to reveal the message of the composers. The EkeGusii pop singer Christopher Mosioma’s (Embarambamba) songs have gained fame in Kenya because of their richness in the usage of metaphors. One of Christopher Mosioma’s songs, amasomo (education) which was launched in 2015 has gained acclaim from Kenyans. The song amasomo (education) is basically presented as a piece of advice to students to embrace education in order to optimally reap from its benefits. The study identified 10 metaphors in the song amasomo (education) through the Metaphor Identification Procedure Vrije Universiteit. In order to interpret the metaphors in the EkeGusii pop song amasomo (education), the Conceptual Metaphor Theory complemented by the folk conception of the generic Great Chain of Being Metaphor were employed. The study employed four coders (including the researchers) in the identification of the metaphors. The study found that, inter alia, animal, plant and object metaphors are used in the song amasomo (education). The study concludes that the metaphors in the EkeGusii pop songs belong inherently to different levels of the generic Great Chain of Being Metaphor.

scholarly journals Assessing the Impacts of Hierarchical Healthcare System on the Accessibility and Spatial Equality of Healthcare Services in Shenzhen, China

2021 ◽  
Vol 10 (9) ◽  
pp. 615
Author(s):  
Zhuolin Tao ◽  
Wenchao Han
Keyword(s):  
Healthcare System ◽  
Catchment Area ◽  
Healthcare Services ◽  
Utilization Efficiency ◽  
Delivery Of Healthcare ◽  
Healthcare Accessibility ◽  
Set Up ◽  
Different Levels

The hierarchical healthcare system is widely considered to be a desirable mode of the delivery of healthcare services. It is expected that the establishment of a hierarchical healthcare system can help provide better and more equal healthcare accessibility. However, limited evidence has been provided on the impacts of a hierarchical healthcare system on healthcare accessibility. This study develops an improved Hierarchical two-step floating catchment area (2SFCA) method, which incorporates variable catchment area sizes, distance friction effects and utilization efficiency for facilities at different levels. Leveraging the Hierarchical 2SFCA method, various scenarios are set up to assess the accessibility impacts of a hierarchical healthcare system. The methods are applied in a case study of Shenzhen. The results reveal significant disparity and inequality in healthcare accessibility and also differences between various facility levels in Shenzhen. The overall healthcare accessibility and its equality can be significantly improved by fully utilizing existing facilities. It is also demonstrated that allocating additional supply to lower-level facilities can generate larger accessibility gains. Furthermore, allocating new supply to primary facilities would mitigate the inequality in healthcare accessibility, whereas inequality tends to be aggravated with new supply allocated to tertiary facilities. These impacts cannot be captured by traditional accessibility measures. This study demonstrates the pivotal role of primary facilities in the hierarchical healthcare system. It can contribute to the literature by providing transferable methods and procedures for measuring hierarchical healthcare accessibility and assessing accessibility impacts of a hierarchical healthcare system in developing countries.

scholarly journals Strength Characteristics of High Strength Concrete (HSC) with and without Coarse Aggregate

2019 ◽  
Vol 9 (2) ◽  
pp. 4701-4704
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Silica Fume ◽  
High Strength Concrete ◽  
Mechanical Characteristics ◽  
Coarse Aggregate ◽  
High Strength ◽  
Set Up

This paper aimed to investigate the mechanical characteristics of HSC of M60 concrete adding 25% of fly ash to cement and sand and percentage variations of silica fumes 0%,5% and 10% to cement with varying sizes of 10mm,6mm,2mm and powder of granite aggregate with w/c of 0.32. Specimens are tested for compressive strength using 10cm X 10cmX10cm cubes for 7,14,28 days flexural strength was determined by using 10cmX10cmX50cm beam specimens at 28 days and 15cm diameter and 30cm height cylinder specimens at 28 days using super plasticizers of conplast 430 as a water reducing agent. In this paper the experimental set up is made to study the mechanical properties of HSC with and without coarse aggregate with varying sizes as 10mm, 6mm, 2mm and powder. Similarly, the effect of silica fume on HSC by varying its percentages as 0%, 5% and 10% in the mix studied. For all mixes 25% extra fly ash has been added for cement and sand.

scholarly journals Determination of mechanical properties of soil under laboratory conditions

2014 ◽  
Vol 60 (Special Issue) ◽  
pp. S66-S69 ◽  
Author(s):  
V. Malý ◽  
M. Kučera
Keyword(s):  
Mechanical Properties ◽  
Penetration Depth ◽  
Measuring Device ◽  
Laboratory Conditions ◽  
Measuring Network ◽  
Set Up ◽  
Different Diameters ◽  
Different Levels ◽  
Properties Of Soil

This paper presents the mechanical properties of soil. In order to determine the properties of soil under laboratory conditions, a special measuring device was constructed, viz. a bevameter. Two types of soil with different levels of moisture were examined and their mechanical properties were determined. Measurements were taken of non-compressed soil. A measuring network was set up, consisting of measuring and recording devices. In the course of measuring, the force and penetration depth of the pressing plate were recorded simultaneously. Three different diameters of pressing plate were used, namely 38, 50 and 70 mm. The pressure on the contact area was calculated after completion of the measurements, and the relationships between pressure and penetration depth were presented graphically.

Introduction, Classification and Implementation of Honeypots

2009 ◽  
pp. 371-382
Author(s):  
Miguel Jose Hernandez y Lopez ◽  
Carlos Francisco Lerma Resendez
Keyword(s):  
Information Security ◽  
Computer System ◽  
Computer Networks ◽  
Production Environment ◽  
Modern Computer ◽  
Educational Environments ◽  
Controlled Environments ◽  
Set Up ◽  
Network Administrators ◽  
Different Levels

This chapter discusses the basic aspects of Honeypots, how they are implemented in modern computer networks, as well as their practical uses and implementation in educational environments, providing the reader with the most important points regarding the main characteristics of Honeypots and Honeynets. Honeypots are defined as “closely monitored network decoys” that can be set by network administrators to deal with a wide variety of attacks and interact with users in different levels (Provos, 2004). The implementation of Honeypots provides an answer to a common question posted by the field of information security and forensics: How to dissect the elements that make up an attack against a computer system. The chapter will summarizes the different features and capabilities of Honeypots once they are set up in a production environment to clarify the elements that are needed to be configured in order for a Honeypot to accomplish its main tasks and in order for it to be considered an effective tool. The end of the chapter will shift towards the analysis of virtualization as an important tool that maximizes the practical use of Honeypots in controlled environments that are focused towards the study of attacks, responses and analysis methods.

TRANSITION PATHWAYS TOWARDS USER-CENTRIC INNOVATION

2008 ◽  
Vol 12 (03) ◽  
pp. 489-510 ◽  
Author(s):  
PHILINE WARNKE ◽  
MATTHIAS WEBER ◽  
KARL-HEINZ LEITNER
Keyword(s):  
Evolutionary Economics ◽  
Learning Spaces ◽  
Niche Markets ◽  
The Past ◽  
Evolution Analysis ◽  
Transition Pathways ◽  
User Centric ◽  
Set Up ◽  
Innovation Paradigms ◽  
Different Levels

Although various user-centric innovation concepts have proved successful in niche markets and specific industries, there is yet little understanding how these models may become more widely diffused in manufacturing industries. We apply an evolutionary economics perspective to explore possible transition pathways towards user-centric innovation paradigms. In order to understand not only the past but also possible future transition trajectories, we complement the co-evolution analysis with prospective elements such as scenario building and roadmapping. Using this combined approach, we identify possible future working configurations of user-centric innovation models and specify a number of diverse elements relevant on different levels of the transition arena. We argue that these insights can be used to define and set-up dedicated learning spaces for user-centric innovation. It is suggested that similar approaches may be useful for companies and policy actors to guide governance of change towards user-centric innovation models.

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