Summary
The integrated OWC‐PON architecture has a potential to overcome the limitations of existent RF technology and eliminate the last mile bottleneck in geographically constrained access networks ...thus providing real sense broadband from core to user. However, phenomenon such as atmospheric turbulence causes performance degradation in such systems. In the dissemination of multimedia services, the performance is the ultimate quality as perceived by end user's visual senses. To ascertain this quality in quantitative terms, full reference quality metrics are employed for communication purposes. This paper deals with classification, evaluation and analysis of various image quality assessment metrics for image transmission over OWC channel under varying turbulent conditions. The performance enhancement in terms of these metrics is investigated by deploying MIMO diversity reception. Moreover, a prediction model for SSIM is developed and compared for both SISO and MIMO links. The results show an improvement in IQA metrics with diversity reception. SSIM can be predicted in terms of log of refractive index structure parameter by a fourth order polynomial model for both SISO and MIMO receptions under all regimes of turbulence. The goodness of the fit statistics is presented along with the models to provide for their accuracy and reliability.
In the dissemination of multimedia services, the performance is the ultimate quality as perceived by end user's visual senses. To ascertain this quality in quantitative terms, full reference quality metrics are employed for communication purposes. This paper deals with classification, evaluation and analysis of various image quality assessment metrics for image transmission over OWC channel under varying turbulent conditions. The performance enhancement in terms of these metrics is investigated by deploying MIMO diversity reception.
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Summary
Underwater wireless optical communication (UWOC) turns out to be a primary sought alternative to wireless technology, which can provide high data rate, enormous bandwidth, and low deployment ...cost and resolve the crowded radio frequency band issues. The performance of the UWOC link is significantly affected by the turbulent ocean environment. In this paper, the different turbulence scenarios such as salinity gradients, temperature gradients, and air bubbles are considered to model the turbulent nature of the ocean environment experimentally. These turbulent conditions induce severe intensity fluctuations in the received optical signal. These intensity fluctuations are modeled stochastically, and a novel turbulence channel model is proposed, which excellently fitted with the experimental data. The conformity of the proposed model is validated by performing a goodness of fit test in terms of R2 and root mean square error (RMSE) coefficients. The results show that for all the considered turbulent scenarios, the Gaussian mixture model better approximates the experimental observations than the Weibull distribution. As the strength of the turbulence increases, the chances of link outage and the probability of bit errors increase. At a flow rate of 4 L/min, the bit error rate (BER) of 10−20, 10−14, and 10−10 is recorded under clear water, salinity, and temperature gradient channel conditions, respectively. It is observed that the air bubbles have a significant impact on the propagating optical beam in comparison to temperature and salinity‐induced turbulence. Moreover, a close agreement between the proposed model and the experimental data is also observed, which makes the proposed model more appropriate to describe the turbulent ocean environment.
In this paper, a novel Gaussian mixture model is proposed to characterize the different turbulence scenarios such as salinity gradients, temperature gradients, and air bubbles. The results reveal that the presence of air bubbles affects the system more than the salinity and temperature‐induced fluctuations. Moreover, a close agreement between the proposed model and the experimental data is also observed, which makes the proposed model most appropriate to describe the turbulent ocean environment.
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Summary
The dimming control feature of light‐emitting diode (LED) makes it a viable candidate for indoor lighting applications. In this study, the performance of variable pulse position modulation ...(VPPM) based visible light communication (VLC) system is investigated in detail for an office room of 5 × 5 × 3‐m3 dimensions. A total of four LED lamps having Lambertian radiation patterns are mounted over the ceiling of the room. Several receiver locations are chosen over the three different trajectories to evaluate the error performance of the proposed system. The height of the receiver plane is also varied to find the optimum height where error‐free data reception is achieved. Moreover, an effort is made to optimize the dimming percentage of the transmitted signal using VPPM in terms of bit error rate (BER), where the illumination requirements over the receiver plane are also as per the International Standards of Organization (ISO). The results show that the duty cycle of 50% is optimum for efficient system performance. Furthermore, a colored image is transmitted through the proposed system and the computed results reveal that satisfactory BER performance and good quality of the image is received at receiver heights ranging from 0.85 to 1.7 m, that is, approximately 2.75 to 5.6 ft above the ground plane.
In this article, an effort is made to optimize the dimming percentage of the transmitted signal using variable pulse position modulation (VPPM) in terms of bit error rate (BER). The results show that 50% dimming is optimum for efficient system performance. Furthermore, a colored image is transmitted and the results reveal that satisfactory BER performance and good quality of the image are received at receiver heights ranging from 0.85 to 1.7 m above the ground plane.
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Nanomaterials are gaining enormous interests due to their novel applications that have been explored nearly in every field of our contemporary society. In this scenario, preparations of nanomaterials ...following green routes have attracted widespread attention in terms of sustainable, reliable, and environmentally friendly practices to produce diverse nanostructures. In this review, we summarize the fundamental processes and mechanisms of green synthesis approaches of TiO2 nanoparticles (NPs). We explore the role of plants and microbes as natural bioresources to prepare TiO2 NPs. Particularly, focus has been made to explore the potential of TiO2‐based nanomaterials to design a variety of sensing platforms by exploiting the photocatalysis efficiency under the influence of a light source. These types of sensing are of massive importance for monitoring environmental pollution and therefore for inventing advanced strategies to remediate hazardous pollutants and offer a clean environment.
Green route‐mediated sustainable synthesis of TiO2 nanomaterials and their photocatalysis‐mediated sensing for monitoring environmental pollution and towards the possible remediation strategies.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Sugarcane production technologies being developed by research institutions are highly location specific and require multi-location trials in diverse conditions before adoption. In India, ...multi-location trials of technologies are conducted under All India Coordinated Research Project (AICRP) on Sugarcane through a network of 36 centres in four disciplines of crop improvement, crop production, entomology and plant pathology. Monitoring and evaluation of trials is accomplished through experts’ field visits, meetings and workshop. Sugarcane being a long duration crop, a large amount of trial observation data are recorded by centres at various crop stages. Data are analysed, compiled and documented by centre officials, principal investigator and project coordinator for interpretation of trial results. Traditional system of data management poses many issues such as retyping of data, late reporting, wrong/missing data, poor documentation, wrong interpretation and poor decision support. A web-based software AICRP Reporter has been implemented for recording and reporting of AICRP trial data to solve these problems and to increase efficiency. Paper gives brief information about the data management technique used in this system for an effective coordination among various AICRP stakeholders for achieving its objectives. System enables timely reporting of data; consistent and reliable reports; and remote monitoring. Data once recorded can be utilized in historical perspective for new knowledge discovery. System is generic in nature and can be implemented for other such research organizations at national and international level with specific knowledge updation.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this article, the acceleration attained in gain recovery dynamics of travelling-wave-type semiconductor optical amplifier (SOA) at the expense of structural optimization is illustrated via ...numerical simulations. A pump–probe scheme has been utilized in order to study the outcomes of optimization of SOA operational and structural parameters on its effective gain recovery time (
τ
e
). A set of optimized SOA parameters are formulated from gain recovery dynamics studies after keeping practical implementation considerations in vision. Further, the impacts of altering SOA structural and operational parameters such as injection current (
I
), amplifier length (
L
), active region width (
w
), active region thickness (
t
) and optical confinement factor (
Γ
) on gain recovery time improvement achieved are further investigated on the performance of a cross-gain modulation (XGM) in SOA-based all-optical half-subtracter in terms of two designated performance metrics: quality factor (Q-factor) and extinction ratio (ER). It has been revealed that reduced gain recovery time-optimized SOAs-based all-optical half-subtracter arranged in a co-propagating manner exhibits improved Q-factor and ER (dB) performance at high bit rates of operation (
≤
80 Gbps).
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
An all-optical half-subtracter is proposed based on harnessing of 3rd order (
χ
(
3
)
) non-linear effects such as cross-gain modulation (
XGM
) and cross-phase modulation (
XPM
) inside a single ...highly non-linear finer (
HNLF
), which is capable of operating at 100 Gbps operating bit rate. The
XGM
effect occurrence in
HNLF
has been exploited for the implementation of both borrow logics
A
.
B
¯
&
A
¯
.
B
. Whereas, the difference output of proposed half-subtracter represented by
A
⊕
B
logic is obtained from
XPM
process taking place on low-energy continuous-wave (
CW
) probe signal which is co-propagating with two high energy pump signals. The proposed half-subtracter can exhibit cascadability, owing to single wavelength centric nature of all the three logic functions generated such as
A
.
B
¯
,
A
¯
.
B
&
A
⊕
B
. The proposed half-subtracter functionality is verified through inspection of temporal waveforms and eye diagrams of achieved output logic functions. Further, dependence of output function’s
Q
-
factor
and Extinction Ratio (dB) values on following parameters: pump/data signal powers (
P
A
&
P
B
), CW probe power (
P
CW
) and choice of
CW
probe operating wavelength (
λ
CW
) is also investigated and discussed. In the final stages, an investigation has been carried out by implementing secondary logic functions
A
.
B
¯
.
C
¯
,
A
.
B
¯
¯
.
C
,
A
¯
.
B
.
C
¯
,
A
¯
.
B
¯
.
C
,
A
⊕
B
¯
.
C
&
A
⊕
B
.
C
¯
to examine the cascade-ability characteristics of the proposed half-subtracter. It has been shown by calculating temporal waveforms and eye diagrams of secondary logic functions such as
A
.
B
¯
.
C
¯
,
A
.
B
¯
¯
.
C,
A
¯
.
B
.
C
¯
,
A
¯
.
B
¯
.
C
,
A
⊕
B
¯
.
C
&
A
⊕
B
.
C
¯
that proposed cross-modulation effects in HNLF based half-subtracter is indeed cascadable.
Summary
In this article, an indoor environment of 5 × 5 × 3 m3 dimensions is considered and a total of nine LED lamps are installed at the ceiling in a symmetrical pattern. The inter‐spatial ...separation between LED lamps is varied to achieve the dual purpose of lighting and communication services. The multipath channel impulse response for distinct receiver locations is also calculated under line‐of‐sight (LOS) and non‐line‐of‐sight (NLOS) channel conditions. Several performance parameters, that is, illumination uniformity, received power fluctuations, root‐mean‐delay spread (RMDS), are evaluated to estimate the performance of the proposed system. The results show that spatial separation of 1.5 m between the LED lamps outperforms the other considered spatial separations, and the error‐free data transmission rate for the proposed system comes out to be about 40 Mbps across the entire receiver plane. Furthermore, an RGB image is transmitted at 40 Mbps and the received image quality is estimated in terms of image quality parameter, that is, structure similarity index (SSIM) over the receiver plane. The results outlined that the received image shows 100% similarity with the transmitted image, and thus, the proposed system can be effectively deployed in practical indoor environments.
In this article, an effort has been made to optimize the spatial separation between LED lamps arranged in a symmetrical pattern in terms of uniformity, received power fluctuations, root‐mean‐delay. The results show that spatial separation of 1.5 m between the LED lamps outperforms the other spatial separations for a room of 5 × 5 × 3 m3 dimensions. Furthermore, image transmission is performed at 40 Mbps, and the received image quality is estimated in terms of structure similarity index (SSIM) over the receiver plane.
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Luthrodes pandava Horsfield (Lepidoptera: Lycaenidae) has been reported as a pest of cycad plants in the Andaman and Nicobar Islands, India for the first time. Its impact on host species is assessed. ...Compared to introduced species, endemic cycads appear to be most susceptible to damage by its larvae, feeding on the plant and affecting growth. Larvae damage all above‐ground plant parts. C. dharmrajii L. J. Singh and C. pschannae R.C. Srivast. & L. J. Singh, endemic to the Andaman and Nicobar Islands, are recorded here for the first time as new host plants.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Soil is one of the most important assets of the planet Earth, responsible for maintaining the biodiversity and managing the ecosystem services for both managed and natural ecosystems. It encompasses ...large proportion of microscopic biodiversity, including prokaryotes and the microscopic eukaryotes. Soil microbiome is critical in managing the soil functions, but their activities have diminutive recognition in few systems like desert land and forest ecosystems. Soil microbiome is highly dependent on abiotic and biotic factors like pH, carbon content, soil structure, texture, and vegetation, but it can notably vary with ecosystems and the respective inhabitants. Thus, unboxing this black box is essential to comprehend the basic components adding to the soil systems and supported ecosystem services. Recent advancements in the field of molecular microbial ecology have delivered commanding tools to examine this genetic trove of soil biodiversity. Objective of this review is to provide a critical evaluation of the work on the soil microbiome, especially since the advent of the NGS techniques. The review also focuses on advances in our understanding of soil communities, their interactions, and functional capabilities along with understanding their role in maneuvering the biogeochemical cycle while underlining and tapping the unprecedented metagenomics data to infer the ecological attributes of yet undiscovered soil microbiome. This review focuses key research directions that could shape the future of basic and applied research into the soil microbiome. This review has led us to understand that it is difficult to generalize that soil microbiome plays a substantiated role in shaping the soil networks and it is indeed a vital resource for sustaining the ecosystem functioning. Exploring soil microbiome will help in unlocking their roles in various soil network. It could be resourceful in exploring and forecasting its impacts on soil systems and for dealing with alleviating problems like rapid climate change.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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