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Search Results: 1 - 10 of 342902 matches for " S. Kumar "
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Elegant and Practical Method of Fir Decimation Using Comb Filters in the Field of Digital Signal Processing  [PDF]
S. Arun Kumar, P. Ganesh Kumar
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.79214
Abstract: This paper deals with the technology of using comb filters for FIR Decimation in Digital Signal Processing. The process of decreasing the sampling frequency of a sampled signal is called decimation. In the usage of decimating filters, only a portion of the out-of-pass band frequencies turns into the pass band, in systems wherein different parts operate at different sample rates. A filter design, tuned to the aliasing frequencies all of which can otherwise steal into the pass band, not only provides multiple stop bands but also exhibits computational efficiency and performance superiority over the single stop band design. These filters are referred to as multiband designs in the family of FIR filters. The other two special versions of FIR filter designs are Halfband and Comb filter designs, both of which are particularly useful for reducing the computational requirements in multirate designs. The proposed method of using Comb FIR decimation procedure is not only efficient but also opens up a new vista of simplicity and elegancy to compute Multiplications per Second (MPS) and Additions per Second (APS) for the desired filter over and above the half band designs.
Antioxidant and free radical scavenging activities of edible weeds
S Kumar, D Kumar
African Journal of Food, Agriculture, Nutrition and Development , 2009,
Abstract: Reactive oxygen species (ROS) such as superoxide anions, hydrogen peroxide, and hydroxyl, nitric oxide radicals, play an important role in oxidative stress related to the pathogenesis of various important diseases. Active (or reactive) oxygen species and free radical-mediated reactions are involved in degenerative or pathological processes. Antioxidants act as a major defense against radical mediated toxicity by protecting against the damages caused by free radicals. Antioxidant-based drugs/formulations for the prevention and treatment of complex diseases like atherosclerosis, stroke, diabetes, Alzheimer’s disease, and cancer have appeared during the last three decades. This has attracted a great deal of research interest in natural antioxidants. Flavonoids and phenolic compounds widely distributed in plants which have been reported to exert multiple biological effect, including antioxidant, free radical scavenging abilities, anti-inflammatory and anticarcinogenic activities. Recently there has been an upsurge of interest in the therapeutic potentials of medicinal plants as antioxidants in reducing such free radical induced tissue injury. The aim of the present investigation was to evaluate in vitro antioxidant and free radicals scavenging effect of two edible weeds. Certain weeds are nutritious and eaten as foods or vegetables. In the present study two weeds namely Chenopodium album and Vitis trifolia have been screened for their antioxidant potential by using various in vitro methods. Aqueous leaf extract Chenopodium album and methanolic fruit extract of Vitis trifolia exhibit significant reducing power and free radical scavenging effect on DPPH, hydroxyl, superoxide, hydrogen peroxide radicals. The extracts also inhibit nitric oxide production. All these antioxidant activities were concentration dependent which were compared with standard antioxidants such as BHA, α-tocopherol and ascorbic acid. In addition, total phenolic and total flavonoids contents were determined as gallic acid and catechin equivalents respectively. From the results, C. album leaf extract was found to contain 0.94 % total phenolic contents (gallic acid equivalent) and 0.27 % total flavonoid contents (catechin equivalent). Whereas V. trifolia fruit extract was found to contain 1.23 % phenolic compounds as gallic acid equivalent (GAE) and 0.38 % flavonoid content as catechin equivalent (CE).
Dilepton Emission at Temperature Dependent Baryonic Quark-Gluon Plasma  [PDF]
Shougaijam S. Singh, Yogesh Kumar
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.45082

Dilepton emission is calculated from quark-gluon plasma (QGP) with the consideration of temperature dependent chemical potential (TDCP). The model is considered to be quasi-model and hence take the dynamical quark mass as a finite value dependence on temperature. The temperature in quark mass enhances in the growth of dilepton emission rates. The emission rate of dilepton spectrum is shown in the intermediate mass region (IMR) of 1.0 - 4.0 GeV and its rate is observed to be a strong increasing function of the temperature dependent chemical potential for quark and anti-quark annihilation.

Establishment and molecular characterization of human dermal mesenchymal-like stem cells derived from human scalp biopsy of androgenetic alopecia patient  [PDF]
Pravin Potdar, Kavitha S. Kumar
Stem Cell Discovery (SCD) , 2013, DOI: 10.4236/scd.2013.32012

Development of Dermal cell line has great scope in the field of skin related diseases and regenerative medicine. Alopecia leads to a skin disorder causing balding and its mechanism is not yet understood. In the present study, we have developed and characterized a heterogeneous population of human dermal mesenchymal-like stem cell line from scalp biopsy of androgenetic alopecia patient with a view to isolate cells from the bulge region of the hair follicle. Our study showed that the dermal cells isolated from dermis of skin showed epithelial-like cells expressing CD34 and Keratin 18, which are characteristic of bulge hair follicle cells. These cells also expressed mesenchymal phenotypes and pluripotency markers such as Oct4, Nanog and SOX2. These cells were designated as “Human Dermal Mesenchymal-like Stem Cells (hDMSCs)”. To confirm their epithelial phenotypes, we have grown these cells at low serum concentration and it was observed that 3% serum concentration provided optimum conditions for their growth and maintenance of characteristics. The hDMSCs cells are presently at passage 10. This study reports the establishment of human dermal mesenchymal-like cell line from the dermis of Alopecia patient, which may be used as an in vitro model system to study the mechanism of Alopecia and other related skin disorders.

Fuzzy Inventory Model for Deteriorating Items with Time Dependent Demand and Partial Backlogging  [PDF]
Sushil Kumar, U. S. Rajput
Applied Mathematics (AM) , 2015, DOI: 10.4236/am.2015.63047
Abstract: In this paper we developed a fuzzy inventory model for deteriorating items with time dependent demand rate. Shortages are allowed and completely backlogged. The backlogging rate of unsatisfied demand is assumed to be a decreasing exponential function of waiting time. The demand rate, deterioration rate and backlogging rate are assumed as a triangular fuzzy numbers. The purpose of our study is to defuzzify the total profit function by signed distance method and centroid method. Further a numerical example is also given to demonstrate the developed crisp and fuzzy models. A sensitivity analysis is also given to show the effect of change of the parameters.
An Inventory Model for Perishable Items with Time Varying Stock Dependent Demand and Trade Credit under Inflation  [PDF]
Sushil Kumar, U. S. Rajput
American Journal of Operations Research (AJOR) , 2015, DOI: 10.4236/ajor.2015.55036
Abstract: In the classical inventory models, it is assumed that the retailer pays to the supplier as soon as he received the items and in such cases the supplier offers a cash discount or credit period (permis-sible delay) to the retailer. In this paper we presented an inventory model for perishable items with time varying stock dependent demand under inflation. It is assumed that the supplier offers a credit period to the retailer and the length of credit period is dependent on the order quantity. The purpose of our study is to minimize the present value of retailer’s total cost. Numerical examples are also given to demonstrate the presented mode.
Performance-Economic and Energy Loss Analysis of 80 KWp Grid Connected Roof Top Transformer Less Photovoltaic Power Plant  [PDF]
S. Sathish Kumar, C. Nagarajan
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.76056
Abstract: In India most part receives 4 - 7 kWh of solar radiation per square meter per day with 200 - 250 sunny days in a year. Tamilnadu state also receives the highest annual radiation in India. In this paper, the grid connected photovoltaic plant has a peak power of 80 KWp supplies electricity requirement of GRT IET campus during day time (7 hrs) and reduces load demand and generates useful data for future implementation of such PV plant projects in the Tamilnadu region. Photovoltaic plant was installed in April 2015, monitored during 6 months, and the performance ratio and the various power losses (power electronics, temperature, soiling, internal, network, grid availability and interconnection) were calculated. The PV plant supplied 64,182.86 KWh to the grid from April to September 2015, ranging from 11,510.900 to 10,200.9 kWh. The final yield ranged from 143.886 (h/d) to 127.51 (y/d), reference yield ranged from 201.6 (h/d) to 155.31 (h/d) and performance ratio ranged from 71.3% to 82.1%, for a duration of six months, it had given a performance ratio of 83.82%, system efficiency was 4.16% and the capacity factor of GRT IET Campus for six months was 18.26%. Payback period in years = 9 years 4 months, energy saving per year = 204,400 KWh, cost reduction per year = 1,737,400, Indian rupee = 26,197.30 USD and total CO2reductions per year = 102,200 tons CO2/year.
Performance Analysis of Malicious Node Detection and Elimination Using Clustering Approach on MANET  [PDF]
S. Gopalakrishnan, P. Mohan Kumar
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.76064
Abstract: Mobile Ad hoc Network (MANET) is a significant concept of wireless networks which comprises of thousands of nodes that are mobile as well as autonomous and they do not requires any existing network infrastructure. The autonomous nodes can freely and randomly move within the network which can create temporary dynamic network and these networks can change their topology frequently. The security is the primary issue in MANET which degrades the network performance significantly. In this paper, cluster based malicious node detection methodology is proposed to detect and remove the malicious nodes. Each node within the cluster gets the cluster key from the cluster head and this key is used for the data transaction between cluster head and node. The cluster head checks this key for every data transaction from node and match with their cluster table. If match is valid, and then only it will recognize that this node is belongs to this cluster, otherwise it is decided as malicious node. This paper also discusses the detection of link failure due to the presence of malicious node by determining the gain of each link in the network. The performance of the proposed method is analyzed using packet delivery ratio, network life time, and throughput and energy consumption. The proposed malicious node detection system is compared with the conventional techniques as OEERP (Optimized energy efficient routing protocol), LEACH (Low energy adaptive clustering hierarchy), DRINA (Data routing for In-network aggregation) and BCDCP (Base station controlled dynamic clustering protocol).
Localized muscle fatigue: review of three experiments
Kumar, S;
Brazilian Journal of Physical Therapy , 2006, DOI: 10.1590/S1413-35552006000100003
Abstract: background: fatigue considerably affects rehabilitation and ergonomics. many approaches to this complex phenomenon, ranging from physiological to psychological, have been used to obtain meaningful fatigue measurements. however, none of the methods in the literature measure fatigue directly. it is therefore of considerable interest to determine which indirect methods best represent the state. method: fatiguing contraction was measured at maximum voluntary contraction (mvc) and 40% mvc in the biceps brachii, quadriceps and erector spinae muscles (three separate experiments). the most-reported objective measurements (contraction force, median electromyographic frequency, heart rate, muscle bed oxygenation and muscle blood volume) and subjective measurements (visual analog score, body part discomfort rating and perceived exertion rate) were simultaneously recorded. the data from the three experiments underwent separate statistical analysis. descriptive statistics, linear mixed effects (to examine force fatigue predictability) and trend analysis (with between and within-subject correlations) were calculated. results: univariate anova on all objective variables showed that gender was a significant factor (p<0.001). all subjective and objective variables were significant (p<0.050.001) in predicting force fatigue. however, the percentage variability explained remained small. by combining variables, the variability explained increase to between 60.2% and 71.9%. correlations between variables were small but significant (p<0.050.001). among single variables, median electromyographic frequency was a slightly better predictor of mvc fatigue (p<0.001) and visual analog score for sub-mvc (p<0.001). conclusion: it is desirable not to measure or predict fatigue based on one variable alone. combining variables improves measurement and prediction. single-variable indexing of localized muscle fatigue is problematic.
S. Kumar
South African Journal of Industrial Engineering , 2012,
Abstract: ENGLISH ABSTRACT: It is assumed that input values in a mathematical model may change frequently due to interactions that may be external or internal and/or may be due to design considerations. This changing environment is typical in a design situation where various possibilities are tried out before accepting one as the final design. Within the changing environment, a solution procedure has been described that attempts to obtain the solution to the changed problem by using the information and results already available from the solution of the problem that was obtained before changes occurred. The author in [15] has called this a ‘path-way’ approach, and terms all such methods based on this philosophy as “information recycling mathematical methods”. In this paper, a geometric program (GP) is considered under a protean environment. AFRIKAANSE OPSOMMING: Die insetwaardes van ‘n wiskundige model verander dikwels as gevolg van interne of eksterne interaksies en/of ontwerpaanpassings. Al te dikwels vind dit plaas wanneer die ontwerpomgewing vereis dat verskeie ontwerpe oorweeg moet word voordat ‘n finale besluit gemaak word. Vir hierdie situasie word ‘n oplossing beskryf wat tred hou met die milieu van verandering. Die outeur beskryf die metode via die analoog van ‘n “voetpad”-benadering, en doop die filosife met die elegante naam “wiskunde sikliese inligtingsmetodes”. Geometriese programmering word ingespan in ‘n proteusagtige omgewing.
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