658 research outputs found
Wikis: Tool for Altering Tacit Knowledge Explicit
No full textThe paper presentsives an overview of the concept and dimensions of knowledge and its management in libraries using ICT based systems. Explores how Wikis can be used in libraries to commute the implicit knowledge explicit among the professionals and the users. Discusses in detail the scope of Wikis implementation in libraries. Explains the relative advantage and weakness of Wikis as a knowledge management tool in libraries
Stolephorus tamilensis Pavan-Kumar & Jahageerdar & Jaiswar 2020, sp. nov.
No full text<i>Stolephorus tamilensis</i> sp. nov. <p>Proposed common name: Tamil anchovy (Fig. 2)</p> <p> <b>Holotype</b>: ZSI F12077/2 (50.85 mm SL), Thoothukudi fish landing centre, Tamil Nadu, India (8.7642° N, 78.1348° E), 18 February 2015.</p> <p> <b>Paratypes:</b> All paratypes from Thoothukudi fish landing centre, Tamil Nadu, India, (8.7642° N, 78.1348° E), (Fig. 1) 18 February 2015: BNHS MF 10-12 (3 specimens, 48.48–51.16 mm SL), CIFE-FRM 945–971 (27 specimens, 47.37–53.64 mm SL) collected by Shardul S. Gangan on 18 February 2015.</p> <p> <b>Diagnosis.</b> A species of <i>Stolephorus</i> with the following combination of characters: relatively deep-bodied fish, 19.87–23.37% SL (mean 21.2%); eye relatively large, eye diameter 29.28–35.85% HL (mean 32.09%); posterior margin of preopercle indented; gill rakers 15–19 in upper series on first gill arch, 25–28 on in lower series, 40–47 in total; posterior tip of longest pectoral-fin ray not reaching pelvic-fin origin, pelvic-fin relatively short, 5.81–8.15% SL (mean 7.39%); no pre-dorsal spines and post-pelvic scutes, pre-pelvic scutes 5–6; dorsal-fin base length 13.85– 15.54% in SL (mean 14.57%); dorsal-fin origin is closer to base of caudal fin than to tip of snout; length from dorsal-fin origin to anal-fin origin 20.91–22.57 % in SL (mean 21.87%); anal-fin rays 17–19; numerous melanophores on dorsum and suborbital area.</p> <p> <b>Description.</b> Body cylindrical, laterally compressed. Dorsal profile of head and body slightly convex from snout tip to dorsal fin origin, somewhat straight from the last point to caudal peduncle. Ventral profile of head and body is convex from anterior lower jaw tip to base of pelvic-fin, slightly concave from post pelvic fin to anal-fin origin. Posterior margin of pre- opercule concave, indented. Numerous melanophores on dorsum and suborbital area. Somewhat straight from posterior end of anal-fin to origin of lower caudal-fin lobe. Caudal peduncle slightly deep than longer. Vertebrae 39–40 (two specimens examined). Belly covered with 5–6 sharp needle-like scutes anterior to pelvic-fin insertion. Pelvic-fin without spine. Pre-dorsal and post-pelvic scutes absent.</p> <p>Snout long, rounded, its length less than eye diameter. Mouth sub-terminal, extending backward beyond posterior margin of eye. Posterior end of the upper jaw rounded reaching to border of operculum. Lower jaw slender, extending beyond vertical through posterior margin of eye. Teeth pointed, small, slender, arranged in a single row in the pre maxilla, maxilla and lower jaw. Eye large, round, covered with adipose eye lid, positioned laterally on head dorsal to horizontal through pectoral-fin insertion, visible in dorsal view. Orbit elliptical. Nostrils close to each other, anterior to orbit. Inter orbital width less than eye diameter.</p> <p>Dorsal-fin rays ii–iii + 15, origin closer to base of caudal-fin than to tip of snout. Pair of pigment line in front of dorsal-fin as well as between caudal-fin and dorsal-fin is absent. Anal-fin rays iii + 17–19, its origin at vertical through middle of the dorsal-fin. Pectoral-fin rays I + 13, posterior tip of longest pectoral-fin ray not reaching pelvic-fin origin, pectoral-fin axillary scale found in some specimens but in the remained it was absent, may be lost during collection. Pelvic-fin rays i–ii + 7, longest pectoral-fin rays not reaching vertical through to base of dorsal-fin. Caudal-fin forked, upper and lower lobes of caudal-fin well-developed. Gill rakers long and thin on first branchial arch, 15 –19 on the upper arch, 25–28 on lower arch (Table 4).</p> <p> <i>Colour.</i> Colour of thirty specimens of <i>Stolephorus tamilensis</i> <b>sp. nov.</b> in fresh condition silvery whitish, very faint silvery stripe running along the lateral side; small dark pigment line running along upper border of anal fin.</p> <p> <b>Distribution.</b> Based on the collection of voucher specimens from present study, the type locality of <i>Stolephorus tamilensis</i> sp. nov. is Thoothukudi, Tamil Nadu State of India 8.7642° N, 78.1348° E. Probably this species is distributed in Gulf of Mannar and along the Tamil Nadu State coast.</p> <p> <b>Etymology.</b> The species is named as “ <i>tamilensis</i> ” with reference to the Tamil Nadu, a state of India, the type locality of the species.</p> <p> <b>Comparisons.</b> <i>Stolephorus tamilensis</i> differs from congeners except <i>S. dubiosus, S. baganensis, S. bengalensis, S. carpenteriae, S. tri, S. ronquilloi, S. holodon,</i> and <i>S. andhraensis</i> by the hind boarder of the pre-operculm concave (<i>vs.</i> rounded in <i>S. indicus</i>, <i>S. commersonnii, S. waitei, S. chinensis, S. multibranchus, S. brachycephalus, S. advenus, S. nelsoni, S. apiensis, S. pacificus, S. continentalis, S. insignus</i> and <i>S. oceanicus</i>). The new species also distinguishes from <i>S. dubiosus, S. tri</i> and <i>S. baganensis</i> by the absence of pre-dorsal spine (<i>vs.</i> presence). Furthermore, <i>S. tamilensis</i> can be distinguished from <i>S. andhraensis</i> by the absence of scattered pigments between dorsal-fin and caudal peduncle (<i>vs.</i> presence). In addition, <i>Stolephorus tamilensis</i> is also distinct from <i>S. andhraensis</i>, <i>S. ronquilloi, S. tri, S. multibranchus, S. brachycephalus, S. apiensis, S. pacificus, S. insignus, S. continentalis, S. teguhi, S. baganensis</i>, <i>S. waitei, S. chinensis, S. bataviensis, S. baweanensis, S. bengalensis</i> and <i>S. oceanicus</i> by 25–28 gill rakers on the lower limb of the first gill arch (<i>vs</i>. 20–21 in <i>S. andhraensis,</i> 28–30 in <i>S. ronquilloi</i>, 18–22 in <i>S. tri,</i> 32–35 in <i>S. multibranchus,</i> 20–22 in <i>S. brachycephalus,</i> 30–31 in <i>S. apiensis,</i> 35–38 in <i>S. pacificus,</i> 26–28 in <i>S. insignus & S. continentalis</i>, 41–46 in <i>S. teguhi,</i> 20–23 in <i>S. baganensis</i>, 23–25 in <i>S. waitei,</i> 20–25 in <i>S. chinensis,</i> 19–22 in <i>S. bataviensis & S. baweanensis,</i> 22–27 in <i>S. bengalensis</i> and 24–28 in <i>S. oceanicus</i>). The new species also differs from <i>S. commersonnii, S. multibranchus, S. brachycephalus, S. advenus, S. pacificus</i>, <i>S. teguhi, S. chinensis, S. insignus, S. bataviensis</i> and <i>S. bengalensis</i> by 5–6 needle like pre-pelvic scutes (<i>vs.</i> 1–4 in <i>S. commersonnii,</i> 2–4 in <i>S. multibranchus,</i> 4–5 in <i>S. brachycephalus,</i> 7 in <i>S. advenus,</i> 1–4 in <i>S. pacificus</i>, 2–5 in <i>S. teguhi,</i> 4–7 in <i>S. chinensis, S. insignus</i> & <i>S. bataviensis,</i> and 5–8 in <i>S. bengalensis</i>). <i>Stolephorus tamilensis</i> is distinguishable from <i>S. multibranchus, S. brachycephalus, S. carpentariae, S. advenus, S. teguhi, S. chinensis, S. bengalensis</i> and <i>S. insignus</i> by 17–19 anal fin rays (<i>vs.</i> 18–20 in <i>S. multibranchus,</i> 19–22 in <i>S. brachycephalus,</i> 19–20 in <i>S. carpenteriae,</i> 16 in <i>S. advenus</i>, 19–21 in <i>S. teguhi,</i> 18–20 in <i>S. chinensis</i>, 16–19 in <i>S. bengalensis</i> and 18–19 in <i>S. insignus</i>).</p> <p> Furthermore, <i>S. tamilensis</i> differs from <i>S. commersonnii, S. indicus, S. waitei</i> (<i>S. baweanensis</i> sensu Hata <i>et al</i>. 2019), <i>S. insularis</i> (<i>S</i>. <i>bengalensis</i> sensu Hata <i>et al.</i> 2019), <i>S. baganensis, S. dubiosus</i> in eye diameter, dorsal fin base length, pelvic fin length, length between dorsal and anal-fin origins and maximum body depth (Table 3).</p> <p>...Continued next page</p> <p> * <i>S. waitei</i> (<i>Stolephorus baweanensis</i> sensu Hata <i>et al</i>. 2019), * <i>S. insularis</i> (<i>S. bengalensis</i> sensu Hata <i>et al</i>. 2019)</p> <p> <b>Note:</b> standard length or SL, snout length SNL (1), head length HL (2), postorbital head length POHL (3), interorbital width IOW (4), eye diameter ED (5), upper jaw length UJL (6), lower jaw length LJL (7), dorsal-fin base length DFBL (8), anal-fin base length AFBL (9), pelvic-fin base length PFBL (10), pelvic-fin length PLFL (11), pectoral-fin base length PTBL (12), pectoral fin long filament length PTFL (13), length from tip of snout to origin of dorsal fin TSDF (14), length from tip of snout to origin of anal fin TSAF (15), length from tip of snout to origin of pelvic fin TSPF (16), length from tip of snout to origin of pectoral fin TSPTF (17), length from origin of dorsal fin to origin of anal fin AFDL (18), maximum body depth MBD (19), length from base of pectoral fin to origin of pelvic fin BPTFPL (20), length from base of pectoral fin to origin of anal fin BPTFAL (21), length from base of pelvic fin to origin of anal fin BPLFAF (22)</p> <p> <b>Statistical analysis of morphometric variables.</b> Higher F-ratio of more than 200 for ED/HL, DFBL/SL, PLFL/SL, AFDL/SL and MBD/SL reveal their better discrimination power than the other characters (Table 3). Herein, a higher F-value of 3309.651 and 2471.632 for ED/HL and MBD/SL, respectively, showed the importance of insertion point in species differentiation. However, comparative analysis showed overlapping meristic characters between <i>S. insularis</i> (<i>S. bengalensis</i> sensu Hata <i>et al.</i> 2019) and <i>S. tamilensis</i> (Table 4).</p>Published as part of <i>Pavan-Kumar, Annam, Jahageerdar, Shrinivas & Jaiswar, A. K., 2020, A new species of Stolephorus (Clupeiformes: Engraulidae) from the Bay of Bengal India, pp. 561-574 in Zootaxa 4743 (4)</i> on pages 563-568, DOI: 10.11646/zootaxa.4743.4.6, <a href="http://zenodo.org/record/3690639">http://zenodo.org/record/3690639</a>
Learning a common dictionary for CSI feedback in FDD massive MU-MIMO-OFDM systems
No full textIn a transmit preprocessing aided frequency division duplex (FDD) massive multi-user (MU) multiple-input multiple-output (MIMO) scheme assisted orthogonal frequency-division multiplexing (OFDM) system, it is required to feed back the frequency domain channel transfer function (FDCHTF) of each subcarrier at the user equipment (UE) to the base station (BS). The amount of channel state information (CSI) to be fed back to the BS increases linearly with the number of antennas and subcarriers, which may become excessive. Hence we propose a novel CSI feedback compression algorithm based on compressive sensing (CS) by designing a common dictionary (CD) to reduce the CSI feedback of existing algorithms. Most of the prior work on CSI feedback compression considered single-UE systems. Explicitly, we propose a common dictionary learning (CDL) framework for practical frequency-selective channels and design a CD suitable for both single-UE and multi-UE systems. A set of two methods is proposed. Specifically, the first one is the CDL-K singular value decomposition (KSVD) method, which uses the K-SVD algorithm. The second one is the CDL-orthogonal Procrustes (OP) method, which relies on solving the orthogonal Procrustes problem. The CD conceived for exploiting the spatial correlation of channels across all the subcarriers and UEs compresses the CSI at each UE, and upon reception reconstructs it at the BS. Our simulation results show that the proposed dictionary’s estimated channel vectors have lower normalized mean-squared error (NMSE) than the traditional fixed Discrete Fourier Transform (DFT) based dictionary. The CSI feedback is reduced by 50%, and the memory reduction at both the UE and BS starts from 50% and increases with the number of subcarriers
Transient response analysis in IBR-dominated power systems based on short circuit ratio
No full textInverter-based resources (IBRs) play a major role in transition to renewable energy, which poses new threats to the power grid’s stability and dependability. As convention a synchronous generators are replaced by IBR causes decrease in the inertia of the grid. As the penetration level rises, the grid’s strength decreases, making it more vulnerable to disturbances. This paper presents a dynamic performance evaluation of a grid-following inverter(GFLI) under varying grid strengths, characterized by different Short Circuit Ratios (SCRs). The inverter is designed with a constant DC voltage source, an L-filter interface, and a cascaded control structure that includes inner current control loops and outer power control (PQ) executed in the synchronous d q reference frame. The transient behavior and current tracking performance of the inverter are examined by applying a step change in active power reference from 10kW to 11 kW. The Key system responses are observed by time domain simulations. The analysis highlights the influence of grid strength on the Efficiency of the control strategy, especially in weak grid conditions. Results demonstrate that the proposed control strategy maintains stable operation and accurate power delivery under strong to moderately weak grid conditions, while performance degrades significantly under weak grid scenarios (SCR = 1)
Sum-rate maximization of RIS-aided digital and holographic beamformers in MU-MISO systems
No full textReconfigurable holographic surfaces (RHS) are intrinsically amalgamated with reconfigurable intelligent surfaces (RIS), for beneficially ameliorating the signal propagation environment. This potent architecture significantly improves the system performance in non-line-of-sight scenarios at a low power consumption. Briefly, the RHS technology integrates ultra-thin, lightweight antennas onto the transceiver, for creating sharp, high-gain directional beams. We formulate a user sum-rate maximization problem for our RHS-RIS-based hybrid beamformer. Explicitly, we jointly design the digital, holographic, and passive beamformers for maximizing the sum-rate of all user equipment (UE). To tackle the resultant nonconvex optimization problem, we propose an alternating maximization (AM) framework for decoupling and iteratively solving the subproblems involved. Specifically, we employ the zero-forcing criterion for the digital beamformer, leverage fractional programming to determine the radiation amplitudes of the RHS and utilize the Riemannian conjugate gradient algorithm for optimizing the RIS phase shift matrix of the passive beamformer. Our simulation results demonstrate that the proposed RHS-RIS-based hybrid beamformer outperforms its conventional counterpart operating without an RIS in multi-UE scenarios. The sum-rate improvement attained ranges from 8 bps/Hz to 13 bps/Hz for various transmit powers at the base station (BS) and at the UEs, which is significant
Design and identification of an optimal approach for modelling a hybrid renewable energy system
No full textMost power generation relies on fossil fuels, which are both finite resources and major contributors to greenhouse gas emissions. In recent years, renewable energy sources such as solar, wind, and biomass have played an important role in power generation to mitigate these concerns. However, the successful modelling, operation, and integration of these sources into the grid system poses significant challenges due to their inherent variability and dependency on environmental conditions. Due to these challenges, determining the optimal capacity of renewables in a hybrid system is complex. Thus, a robust methodology is required to address this design challenge effectively. To achieve this, development of advanced modelling techniques is suggested that consider the probabilistic nature of renewable energy sources and load patterns. This study analyses different approaches, including the deterministic and probabilistic methods, and proposes an optimal approach and design for a hybrid renewable energy system, which is more reliable with a reduced loss of power supply probability and produces energy with 26.3% lower levelised cost of electricity (LCOE) than fossil fuel–based alternatives such as the utility grid. A detailed analysis of the compatibility of the proposed method with the actual real-time data is carried out, and the effect of the grid purchase and sale capacities on the LCOE of the produced energy is examined
Density based traffic control system
No full textThis paper introduces a density-based traffic control system aimed at optimizing traffic management at intersections. Utilizing Arduino mega 2560, sensor technology, and an LCD display, the system dynamically adjusts signal timings in response to varying traffic densities. By incorporating infrared sensors for vehicle detection and a sound sensor to prioritize emergency vehicles, the system intelligently allocates green light durations to different roadways, minimizing congestion and ensuring smoother traffic flow. Categorizing traffic into high, moderate, and low-density scenarios enhances the system's adaptability to changing traffic conditions. Overall, this paper offers a practical solution for enhancing road safety, reducing travel times, and improving transportation efficiency in urban environments through intelligent traffic control with visual feedback provided by the LCD display
Loss of susceptibility as a novel breeding strategy for durable and broad-spectrum resistance
No full textRecent studies on plant immunity have suggested that a pathogen should suppress induced plant defense in order to infect a plant species, which otherwise would have been a nonhost to the pathogen. For this purpose, pathogens exploit effector molecules to interfere with different layers of plant defense responses. In this review, we summarize the latest findings on plant factors that are activated by pathogen effectors to suppress plant immunity. By looking from a different point of view into host and nonhost resistance, we propose a novel breeding strategy: disabling plant disease susceptibility genes (S-genes) to achieve durable and broad-spectrum resistanc
Seamless transition between grid forming and grid following inverters based on online grid impedance estimation
No full textThe rapid increase in the penetration of inverterbased resources (IBRs) into the distribution network causes thepower system to behave as a weak grid and often alters system strength. IBRs operate as either grid-following (GFL) or grid forming (GFM) inverters, differing in both control stability and inertia support capabilities under varying operating conditions. To maintain system stability across different grid strengths, IBRs need to support smooth switching between GFL and GFM modes. This paper presents an automatic smooth-switching control strategy based on online grid impedance estimation to enhance operational stability. Ordinary Least Squares (OLS) regression is used to estimate grid impedance, and hysteresis switching is applied to prevent continuous switching when grid strength fluctuates near boundary conditions. The effectiveness of the proposed control strategy is verified through case studies under varying grid strengths
Clock multiplication techniques for high-speed I/Os
No full textGeneration of a low-jitter, high-frequency clock from a low-frequency reference clock using classical analog phase-locked loops (PLLs) requires a large loop filter capacitor and power hungry oscillator. Digital PLLs can help reduce area but their jitter performance is severely degraded by quantization error. In this dissertation different clock multiplication techniques have been explored that can be suitable for high-speed wireline systems. With the emphasis on ring oscillator based architecture using cascaded stages, three possible architectures are explored.
First, a scrambling TDC (STDC) is presented to improve deterministic jitter (DJ) performance when used with a low-frequency reference clock. A cascaded architecture with digital multiplying delay locked loop as the first stage and hybrid analog/digital PLL as the second stage is used to achieve low random jitter in a power efficient manner. Fabricated in a 90nm CMOS process, the prototype frequency synthesizer consumes 4.76mW power from a 1.0V supply and generates 160MHz and 2.56 GHz output clocks from a 1.25MHz crystal reference frequency. The long-term absolute jitter of the 60MHz digital MDLL and 2.56 GHz digital PLL outputs are 2.4 psrms and 4.18 psrms, while the peak-to-peak jitter is 22.1 ps and 35.2 ps, respectively. The proposed frequency synthesizer occupies an active die area of 0.16mm2 and achieves power efficiency of 1.86 mW/GHz.
Second, a hybrid phase/current-mode phase interpolator (HPC-PI) is presented to improve phase noise performance of ring oscillator-based fractional-N PLLs. The proposed HPC-PI alleviates the bandwidth trade-off between VCO phase noise suppression and ΔΣ quantization noise suppression. By combining the phase detection and interpolation functions into an XOR phase detector/interpolator (XOR PD-PI) block, accurate quantization error cancellation is achieved without using calibration. Use of a digital MDLL in front of the fractional-N PLL helps in alleviating the bandwidth limitation due to reference frequency and enables bandwidth extension even further. The extended bandwidth helps in suppressing the ring-VCO phase noise and lowering the in-band noise floor. Fabricated in 65nm CMOS process, the prototype generates fractional frequencies from 4.25 to 4.75 GHz, with an in-band phase noise floor of -104 dBc/Hz and 1.5 psrms integrated jitter. The clock multiplier achieves power efficiency of 2.4mW/GHz and FoM of -225.8 dB.
Finally, an efficient clock generation, recovery, and distribution techniques for flexible-rate transceivers are presented. Using a fixed-frequency low-jitter clock provided by an integer-N PLL, fractional frequencies are generated/recovered locally using multi-phase fractional clock multipliers. Fabricated in a 65nm CMOS, the prototype transceiver can be programmed to operate at any rate from 3-to-10 Gb/s. At 10 Gb/s, integrated jitter of the Tx output and recovered clock is 360 fsrms and 758 fsrms, respectively.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-05-01The student, Romesh Kumar Nandwana, accepted the attached license on 2017-04-17 at 15:09.The student, Romesh Kumar Nandwana, submitted this Dissertation for approval on 2017-04-17 at 15:42.This Dissertation was approved for publication on 2017-04-19 at 08:46.DSpace SAF Submission Ingestion Package generated from Vireo submission #10816 on 2017-08-10 at 15:05:48Made available in DSpace on 2017-08-10T20:32:59Z (GMT). No. of bitstreams: 3
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