315 research outputs found
Multi-mode fiber imaging with selective mode control
Single multi-mode fibers are attractive for endoscopy due to their small footprint, high number of degrees of freedom and flexible design. We present an endoscopy system in which the working principle involves calibration of the fiber transmission matrix, calculation of scanning spots in the desired location of the object plane, fluorescence excitation and collection back through the same fiber. Many approaches to multimode fiber imaging have been reported, but a common limitation of all existing methods is the sensitivity of the fiber to environmental perturbations. While, some degree of robustness has been shown in [1] a more methodical control over perturbation resilience is desirable. An analysis of the perturbation effects in a multimode fiber reveals a direct relation to intermodal coupling [2], which suggests that control over the fiber modes can potentially improve fiber robustness. In this presentation we demonstrate a mathematical approach to controlling the fiber modes excited at the distal tip of a multimode fiber.
Towards this end, the desired field in the image plane that defines the location of the focal spot, is decomposed in the fiber modes basis and the new mode coefficients, corresponding to the selected set of fiber modes to be excited, are computed by solving a least squares problem. The estimated mode coefficients allow calculation of the optimal phase mask required at the input of the fiber. Selectively exciting fiber modes to reduce intermodal coupling is promising towards improving robustness of multimode fiber endoscopes.
References:
[1] A. M. Caravaca-Aguirre, E. Niv, D. B. Conkey, and R. Piestun, “Real-time resilient focusing through a
bending multimode fiber,” Opt. Express 21(10), 12881–12887 (2013).
[2] Antonio M. Caravaca-Aguirre and Rafael Piestun, “Single multimode fiber endoscope,” Opt. Express 25,
1656-1665 (2017).
[3] Shay Ohayon, Antonio Miguel Caravaca-Aguirre, Rafael Piestun, James J. DiCarlo, “Deep brain
fluorescence imaging with minimally invasive ultra-thin optical fibers”, arXiv:1703.07633(2017
Interrogating Impunity through Counterpublic: Rethinking Habermas's Public Sphere in Paulaumi Duttagupta's Onaatah of the Earth
The present paper aims at analyzing the inevitable relationship of patriarchal
impunity with counterpublic in India with reference to Onaatah of the Earth (2017) by
Paulami Duttagupta. It is apparent that much of the discourse on counterpublic
emphasizes on either countering the existing state agencies as mentioned by
Nancy Frazer where she critiques the exclusionary practices of bourgeois public
sphere labeling the process as undemocratic or advocating locational counterpublic
to uplift the subalterns to establish democracy discussed by Kanika Batra. However,
not much has been discussed about the exclusion of discourses critiquing impunity
which forms an essential background to establish a correlation between patriarchal
impunity and the counterpublic. Thus, the paper attempts to examine bourgeois
public sphere mainly as a patriarchal discursive arena disseminating and
strengthening the idea of impunity granted, especially in cases of sexual violence
within the framework of Habermas’s public sphere. The study also focuses on how
the novel Onaatah of the Earth acts as a counterpublic to undermine or neutralize
the impunity by addressing issues related to gender sensitivity bringing them
forth not only in discursive space but in activism too
Security Enhancement in Cloud Environment using Secure Secret Key Sharing
Securing the data in distributed cloud system is considered one of the major concern for the cloud customers who faces security risks. The data leakage or data tampering are widely used by attackers to extract the private information of other users who shares the confidential data through virtualization. This paper presents Secure Secret Sharing (SSS) technique which is being recognized as one of the leading method to secure the sensitive data. It shares encrypted data over cloud and generated secret key is split into different parts distributed to qualified participants (Qn) only which is analyzed by malicious checkers. It verifies the clients based on their previous performances, whether these users proved to be authorized participant or not. The key computation is evaluated by the Key handler (KH) called trusted party which manages authorized control list, encryption/decryption and reconstruction of key shares. The Lagrange’s interpolation method is used to reconstruct the secret from shares. The experimental results shows that the proposed secure data sharing algorithm not only provides excellent security and performance, but also achieves better key management and data confidentiality than previous countermeasures. It improves the security by using secure VM placement and evaluated based on time consumption and probability computation to prove the efficacy of our algorithm. Experiments are performed on cloudsim based on following parameters i.e. time computation of key generation; response time and encryption/decryption. The experimental results demonstrate that this method can effectively reduce the risks and improves the security and time consumption up to 27.81% and 43.61% over existing algorithms
Effect of plyometric training on sand versus grass on muscle soreness and selected sport-specific performance variables in hockey players
The purpose of this study was to compare the effects of a 4-week plyometric training on two different surfaces, sand and grass on muscle soreness and selected sport-specific performance variables in national level hockey players. Subjects were randomly divided into two groups- grass training group (N=20) and sand training group (N=20). After the baseline measurements of strength, endurance, balance, and agility, plyometric training was given for 4-weeks,three sessions per week. Muscle soreness was assessed at the end of each training session on a 7-point likert scale.Post-readings of strength, endurance, balance and agility were taken after the 4-week training programme. Data when compared after plyometric training revealed no significant changes between two groups (p>0.05), however players in the sand group experienced less muscle soreness (p<0.05) than grass group. There was significant improvement (p<0.05) seen in the tested variables in both groups after the training but no significant interaction was found between the two surfaces after the training. These findings suggest that short-term plyometric training on sand/non-rigid surface induces similar improvements in strength, endurance, balance and agility as on firm surface but induces significantly less muscle soreness. Hence, plyometric training on sand is viable option for coaches to enhance performance in athletes, while reducing risk of muscle soreness and damage
Empirical optimization of corrosion rate for magnesium-chromium composites
363-368In this study, optimization of the corrosion rate (CR) of Mg-composites has been evaluated by varying the concentration, reinforcement percentage, and immersion time. As prime material, pure Mg is preferred for this research and chromium (Cr) consider as a reinforcing material with different percentages. CR (miles/yr) has been optimized by varying parameters such as reinforcement percentage as 3%, 5% and 7% including NaCl immersion medium (%) as 2.4%, 3.5% and 4.7% with immersion time (h) such as 48h, 72h and 96h. By using, DOF, minimal CR has been measured with the assistance of Minitab Software having ANOVA and Taguchi approaches. Optimized results reveal that the percentage of corrosion solution is influenced upto 66.10%, reinforcement percentage contributed to 27.56% and immersion time influenced upto 2.81%. An optimized combination of CR is 7wt. % Cr with 2.4% NaCl for 96h. However, microscopy results illustrate shallow crack boundaries in Mg/Cr composites due to its chemical reaction in alkaline solution
Dynamic Resource Allocation Method for Load Balance Scheduling over Cloud Data Center Networks
The cloud datacenter has numerous hosts as well as application requests where
resources are dynamic. The demands placed on the resource allocation are
diverse. These factors could lead to load imbalances, which affect scheduling
efficiency and resource utilization. A scheduling method called Dynamic
Resource Allocation for Load Balancing (DRALB) is proposed. The proposed
solution constitutes two steps: First, the load manager analyzes the resource
requirements such as CPU, Memory, Energy and Bandwidth usage and allocates an
appropriate number of VMs for each application. Second, the resource
information is collected and updated where resources are sorted into four
queues according to the loads of resources i.e. CPU intensive, Memory
intensive, Energy intensive and Bandwidth intensive. We demonstarate that
SLA-aware scheduling not only facilitates the cloud consumers by resources
availability and improves throughput, response time etc. but also maximizes the
cloud profits with less resource utilization and SLA (Service Level Agreement)
violation penalties. This method is based on diversity of clients applications
and searching the optimal resources for the particular deployment. Experiments
were carried out based on following parameters i.e. average response time;
resource utilization, SLA violation rate and load balancing. The experimental
results demonstrate that this method can reduce the wastage of resources and
reduces the traffic upto 44.89 and 58.49 in the network
A smart resource management mechanism with trust access control for cloud computing environment
The core of the computer business now offers subscription-based on-demand
services with the help of cloud computing. We may now share resources among
multiple users by using virtualization, which creates a virtual instance of a
computer system running in an abstracted hardware layer. It provides infinite
computing capabilities through its massive cloud datacenters, in contrast to
early distributed computing models, and has been incredibly popular in recent
years because to its continually growing infrastructure, user base, and hosted
data volume. This article suggests a conceptual framework for a workload
management paradigm in cloud settings that is both safe and
performance-efficient. A resource management unit is used in this paradigm for
energy and performing virtual machine allocation with efficiency, assuring the
safe execution of users' applications, and protecting against data breaches
brought on by unauthorised virtual machine access real-time. A secure virtual
machine management unit controls the resource management unit and is created to
produce data on unlawful access or intercommunication. Additionally, a workload
analyzer unit works simultaneously to estimate resource consumption data to
help the resource management unit be more effective during virtual machine
allocation. The suggested model functions differently to effectively serve the
same objective, including data encryption and decryption prior to transfer,
usage of trust access mechanism to prevent unauthorised access to virtual
machines, which creates extra computational cost overhead
- …