81 research outputs found
Development and Testing of a System for Controlled Ultrasound Hyperthermia Treatment With a Phantom Device
No full textHyperthermia is the process of raising tissue temperatures in the range 40 degrees C-45 degrees C for a prolonged time (up to hours). Unlike in ablation therapy, raising the temperature to such levels does not cause necrosis of the tissue but has been postulated to sensitize the tissue for radiotherapy. The ability to maintain a certain temperature in a target region is key to a hyperthermia delivery system. The aim of this work was to design and characterize a heat delivery system for ultrasound hyperthermia able to generate a uniform power deposition pattern in the target region with a closed-loop control, which would maintain the defined temperature over a defined period. The hyperthermia delivery system presented herein is a flexible design with the ability to strictly control the induced temperature rise with a feedback loop. The system can be reproduced elsewhere with relative ease and is adaptable for various tumor sizes/locations and for other temperature elevation applications, such as ablation therapy. The system was fully characterized and tested on a newly designed custom-built phantom with controlled acoustic and thermal properties and containing embedded thermocouples. Additionally, a layer of thermochromic material was fixed above the thermocouples, and the recorded temperature increase was compared to the red, green, and blue (RGB) color change in the material. The transducer characterization allowed for input voltage to output power curves to be generated, thus allowing for the comparison of power deposition to temperature increase in the phantom. Additionally, the transducer characterization generated a field map of the symmetric field. The system was capable of increasing the temperature of the target area by 6 degrees C above body temperature and maintains the temperature to within +/- 0.5 degrees C over a defined period. The increase in temperature correlated with the RGB image analysis of the thermochromic material. The results of this work have the potential to contribute toward increasing confidence in the delivery of hyperthermia treatment to superficial tumors. The developed system could potentially be used for phantom or small animal proof-of-principle studies. The developed phantom test device may be used for testing other hyperthermia systems
Author Correction Large spontaneous exchange bias in a weak ferromagnet Pb 6 Ni 9 (TeO 6 ) 5 (Scientific Reports, (2017), 7, 1, (8300), 10.1038/s41598-017-09056-w)
No full textIn the original version of this Article, Binoy Krishna Hazra and S. Srinath were incorrectly affiliated with ‘Department of Physics, Indian Institute of Technology Tirupati, TIRUPATI, 517506, India’. The correct affiliation is listed below School of Physics, University of Hyderabad, Hyderabad, 500046, India This error has now been corrected in the PDF and HTML versions of the Article, and in the accompanying Supplementary Information file. © 2019, The Author(s)
Experimental characterisation of large scale structures in a high Reynolds number turbulent boundary layer
No full textA very large field of view (4δ x 1δ) with a good spatial resolution owing to the use of four 2k x 2k pixel cameras was conducted in a flat plate boundary layer at two Reynolds numbers (Reθ ≈7,500 and 20,000). Comparing the flow statistics with previously obtained hot-wire data under similar flow conditions show good agreement. The goal of this experiment is to detect and characterise the large scale motions which develop in the log region of a high Reynolds number turbulent boundary layer
Many Worlds on a Frame: Characterizing Online Social Cognition
No full textAbstract :
The theme of the Web Observatory at IIIT Bangalore is "online social cognition." Our research aims to understand how social media activity molds collective worldview that in turn impacts several areas of human activity, like business, politics or even social harmony. We first categorize the web into three broad regions or realms: called the social, trigger, and inert realms respectively. The social realm forms the participatory areas of the web, where opinions are actively exchanged and molded. Trigger realm refers to elements like news websites or blogs, whose publishing events often trigger activity in the social realm. The inert realm refers to static web content, that gets used as a source of latent knowledge in the social interactions.
The social realm itself is modeled as a "marketplace of opinions" -- where different vested interests invest their opinions in order to fetch returns. Opinions that are "compatible" come together to form one or more narratives. In order to characterize this, we first represent an opinion as comprising of two dimensions called: abstraction and expression. Abstraction refers to the opinion-holder's objective perspective on the issue, and expression refers to the communication of the opinion-holder's subjective sentiment about the issue. Cognitive science studies show that abstractions and expressions have vastly different characteristics in they way they diffuse through a population. Hence, the formation of narratives are sometimes catalyzed by abstractions, and sometimes by expressions.
In order to represent narratives and their interplay, that constitutes social cognition, we also propose a hermeneutic framework called "Many Worlds on a Frame" (MWF). The framework models the semantic universe of discourse, as comprising of several semantic "worlds" or "narratives" within each of which , other worlds may participate as entities. Interactions between worlds are either facilitated or hampered by their respective worldviews. The set of all interactions between worlds is called the Frame.
We argue that the "many worlds" representation is more conducive to modeling social cognition, rather than (say) a convergent multi-author knowledge model like a wiki. The MWF implementation does not impose an overarching ontology, at the same time, it is not completely unstructured either. We propose to use a modified form of the NQuad W3C standard for representing knowledge about online social cognition.
About the Speaker :
Srinath Srinivasa heads the Web Science lab and is the Dean (R&D) at IIIT Bangalore, India. Srinath holds a Ph.D (magna cum laude) from the Berlin Brandenburg Graduate School for Distributed Information Systems (GkVI) Germany, an M.S. (by Research) from IIT-Madras and B.E. in Computer Science and Engineering from The National Institute of Engineering (NIE) Mysore. He works in the area of Web Science, understanding the impact of the web on humanity. Technology for educational outreach and social empowerment has been a primary motivation driving his research. He has participated in several initiatives for technology enhanced education including the VTU Edusat program, The National Programme for Technology Enhanced Learning (NPTEL) and an educational outreach program in collaboration with Upgrad. He is a member of various technical and organizational committees for international conferences like International Conference on Weblogs and Social Media (ICWSM), ACM Hypertext, COMAD/CoDS, ODBASE, etc. He is also a life member of the Computer Society of India (CSI). As part of academic community outreach, Srinath has served on the Board of Studies of Goa University and as a member of the Academic Council of the National Institute of Engineering, Mysore. He has served as a technical reviewer for various journals like the VLDB journal, IEEE Transactions on Knowledge and Data Engineering, and IEEE Transactions on Cloud Computing. He is also the recipient of various national and international grants for his research activities
Laser-generated, plane-wave, broadband ultrasound sources for metrology
No full textThe accurate quantification of ultrasound fields generated by diagnostic and therapeutic transducers is critical for patient safety. This requires hydrophones calibrated to a traceable national measurement standard over the full range of frequencies used. At present, the upper calibration frequency range available to the user community is limited to a frequency of 60 MHz. However, there is often content at frequencies higher than this, e.g., through nonlinear propagation of high-amplitude pulses or tone-bursts for therapeutic applications, and the increasing use of higher frequencies in diagnostic imaging. To reduce the uncertainties and extend the calibrations to higher frequencies, a source of high-pressure, plane-wave and broadband ultrasound fields is required. This is not possible with current piezoelectric transducer technology, therefore laser-generated ultrasound is investigated as an alternative. This consists of an ultrasound wave generated by the pulsed laser excitation of a thin, planar, layer of light absorbing carbon-polymer nanocomposite materials. The work described in this thesis can be divided into three parts. The first part consisted of the fabrication of various nanocomposites in order to study the effect of different polymer types, composite thickness, laser fluence, and concentration of carbon nanotubes, on the ultrasound generated, as well as their stability. This included an investigation into the nonlinear propagation of MPa range laser-generated ultrasound, and the effect of the bandlimited hydrophone response, using a numerical wave solver (k-Wave). In the second part, the effects on the signal of acoustically reflective and matched backings (the substrates onto which the nanocomposite was coated) were studied. It was found experimentally that the backing material can significantly affect the pressure amplitude when the duration of the laser pulse is longer than the acoustic transit time across the thin nanocomposite layer. An analytical model was developed to describe how the signal generated depends on the backing material, absorbing layer thickness, and laser pulse duration. The model agreed well with measurements performed with a variable pulse duration fibre-laser. Finally, in the third part, a laser-generated, plane-wave, broadband ultrasound source device superficially resembling a standard piezoelectric piston source was designed, fabricated, and tested. The source produced quasi-unipolar pressure-pulse of 9 MPa peak-positive pressure with a bandwidth of 100 MHz, and the ultrasound beam is sufficiently planar to reduce uncertainties due to diffraction to negligible levels for hydrophones up to 0.6 mm in diameter
A Comprehensive Review on the Viscoelastic Parameters Used for Engineering Materials, Including Soft Materials, and the Relationships between Different Damping Parameters
No full textAlthough the physical properties of a structure, such as stiffness, can be determined using some statical tests, the identification of damping parameters requires a dynamic test. In general, both theoretical prediction and experimental identification of damping are quite difficult. There are many different techniques available for damping identification, and each method gives a different damping parameter. The dynamic indentation method, rheometry, atomic force microscopy, and resonant vibration tests are commonly used to identify the damping of materials, including soft materials. While the viscous damping ratio, loss factor, complex modulus, and viscosity are quite common to describe the damping of materials, there are also other parameters, such as the specific damping capacity, loss angle, half-power bandwidth, and logarithmic decrement, to describe the damping of various materials. Often, one of these parameters is measured, and the measured parameter needs to be converted into another damping parameter for comparison purposes. In this review, the theoretical derivations of different parameters for the description and quantification of damping and their relationships are presented. The expressions for both high damping and low damping are included and evaluated. This study is considered as the first comprehensive review article presenting the theoretical derivations of a large number of damping parameters and the relationships among many damping parameters, with a quantitative evaluation of accurate and approximate formulas. This paper could be a primary resource for damping research and teaching
Detection and classification of electroencephalogram signals for epilepsy disease using machine learning methods
No full textThe Enhanced Role of Banks and Financial Institutions Its Impact on the Agricultural Sector
No full textAgriculture is capital intensive since there are many inputs for cultivation. An
average rural farmer is always in need of funds for the purchase of seeds, pesticides,
hiring farm equipment’s and setting up irrigation etc., they then try to get back their
investment made on the above input hoping that they would have a good harvest. The
farmer allocates the funds received on his harvest for his personal expenses and also
tries to save a portion of his funds received from harvest for his future cultivation
.The problem which generally arises is that, the farmers on several occasions do
not have adequate funds left from their earlier harvest for future cultivation. They
hence tend to depend on banks which play a vital role in financing the deficiencies.
There could be occasions when the yield is very poor, this leads to excess borrowing
by farmers from private lenders at exorbitant rates of interest, hence pulling them
Ä\àC'nder debt.
The banks& other financial institutions play a major role in the life of a farmer
when compared to other institutions which could be, Government or Non
Govt Agriculture support bodies like ICAR(Indian Council for Agriculture
research),NABARD(national Bank for Agriculture and Rural Development),
ICRISAT(International crop Research Institute for
Semi-Arid Tropics) and others, who play an active supporting role in agriculture
However,
Ref: ibef.org
The farmers depend on banks and financial institutions since the interest rates
are much lower and they also hope for a loan waivers by the political parties who
have promised the same.
The banks and financial institutions take limited role in assisting the farmers.
The basic function of banks is to provide financial assistance to the farmers,
however most of the farmers have little knowledge of scientific measures to improve
the productivity apart from the financial weakness and no guidance in improving
farming on latest techniques.
The issue that needs to be addressed for the overall growth of farmers which are
currently vital is as follows;
1. The high cost of labor
2. The high dependence on power.
INTERNATIONAL SCHOOL OF MANAGEMENT EXCELLENCE, Bangalore, Karnataka
250
Vol. 7 Special Issue 1 Febraruy 2020 International Journal of Management
3. The inadequacy of water for irrigation.
4. The ever increasing demand for organic crops.
5. Awareness of technologies to improve yield
6. The availability of latest technologies for better use of irrigation, man power and other basic inputs including
marketing of his produce.
Since the interest rates are comparatively better and the fact that loan waivers for farmers are generally on top
agenda of the political parties in our country. These aspects force the farmers to keep themselves in touch with local
bankers.
It is well known that the initiatives taken by the bankers towards helping the famers is far from satisfactory. Even
though it is true that Banking is basically meant to provide financial assistance to the farmers. It should also be understood
that majority of the farmers who are not prosperous and have suffered problems due to consistent losses are not willing
to take the advice offered by others any government or non-governmental agency professionally when compared to
Banks or Financial Intuitions.
The Banks on their part should take an active part in understanding the Global innovation in Agricultural practices
including irrigation and cropping pattern through their specialized staff and ensure that the same in conveyed in an
effective way to an average farmer. This would not only help the farmer to increase his output but also help in getting
decent profits and help the banker to reduce the bad loans. The effective system of crop management would make the
government ponder on better ways on benefitting the farmer rather than waiving off the loans and make them dependent
for the same in future.
The best example would be the technique to grow crops with minimal water from countries like Israel or technique
of growing rice from salt water from China. It would be difficult for an average farmer to achieve the same without the
support of Banks whom they believe the most. Government departments on their part are doing their best, but without
commitment and confidence of the Farmers it is not possible to plan the entire activity and hence farmers are in the
same state of financial indebtedness. Hence, banks can play a much better role leading to overall improvement of the
agricultural sector in the economy.
The banks good evolve certain standard agricultural practices (here in referred as SAgP) which could be implemented
to improve, monitor and take timely action on improving the yield. This SAgP should be formulated by scientist and
technocrats coordinating together to decide the system. If the same practices is universally implemented it would
strengthened the backbone of Indian economy. Hence it is reiterated again that since Bank have the reach, confidence
and ability to disburse credit and would boost the recovery of loans and issue of fresh loans they would be the best
mechanism to bring in change in agricultural practices
Modelling laser ultrasound waveforms: The effect of varying pulse duration and material properties
No full textUser-Level Communication in Cluster-Based Servers
No full textClusters of commodity computers are currently being used to provide the scalability required by several popular Internet services. In this paper we evaluate an efficient cluster-based WWW server, as a function of the characteristics of the intra-cluster communication architecture. More specifically, we evaluate the impact of processor overhead,network bandwidth, remote memory writes, and zero-copy data transfers on the performance of our server. Our experimental results with an 8-node cluster and four real WWW traces show that network bandwidth affects the performance of our server by only 6%. In contrast, user-level communication can improve performance by as much as 29%. Low processor overhead, remote memory writes, and zero-copy all make small contributions towards this overall gain. To be able to extrapolate from our experimental results, we use an analytical model to assess the performance of our server under different workload characteristics, different numbers of cluster nodes, and higher performance systems. Our modeling results show that higher gains (of up to 55%) can be accrued for workloads with large working sets and next-generation servers running on large clusters.Technical report DCS-TR-45
- …
