Computer simulations were done extensively in order to study non‐linear dynamics of laser‐plasma interaction in InSb semiconductor. We constructed the modified Duffing kind of…
Abstract
Computer simulations were done extensively in order to study non‐linear dynamics of laser‐plasma interaction in InSb semiconductor. We constructed the modified Duffing kind of non‐linear semiconductor plasma oscillator equation. Collision frequency is found to be dominant parameter to influence the bifurcation, chaos, hysteresis and bistable effects of plasma wave. Small windows of higher period cascade above the critical value of laser parameter (α1α2) in the chaos region are observed. Laser‐plasma exhibits too much chaotic regime at lower value of laser driving frequency (δ). Hysteresis and bistable regions of plasma wave are presented and the conditions for their occurence are identified. The unstable regions completely merge at higher value of effective collision frequency (γ).
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Brajesh Kumar Kaushik, Sankar Sarkar, R.P. Agarwal and R.C. Joshi
This paper proposes to study the effect of line resistance and driver width on crosstalk noise for a CMOS gate driven inductively and capacitively coupled VLSI interconnects.
Abstract
Purpose
This paper proposes to study the effect of line resistance and driver width on crosstalk noise for a CMOS gate driven inductively and capacitively coupled VLSI interconnects.
Design/methodology/approach
The paper considers a distributed RLC interconnect topology. The interconnect length is 4 mm and far‐end capacitive loading is 30 fF. The SPICE simulation set‐up uses an IBM 0.13 μm, 1.2 V technology model. The input falling ramp has a transition time of 50 ps. The victim line is grounded through a driver resistance of 50 Ω at near end of interconnect. While observing the effect of line resistance, the aggressor driver has PMOS and NMOS widths of 70 and 30 μm, respectively, and the line resistance is varied from 0 to 500 Ω. For capturing the effect of driver width, SPICE waveforms are generated at far end of victim line for three different line resistances (R=0, 30, and 60 Ω respectively). In each case, the aggressor PMOS driver width is swept from 20 to 100 μm. The corresponding NMOS width is half of PMOS width.
Findings
It is observed that, as line resistance increases, the noise peak reduces. This is due to the fact that with increasing resistance the incident and reflected waves traveling along the line experience increasing attenuation. Hence, the waves arriving at the far‐end of the line are of smaller magnitude and larger time durations. This causes noise pulses in the lossy lines to be smaller and wider compared with those in a lossless line. The effect of driver width on noise waveforms is further observed. It is observed that, as the PMOS (and corresponding NMOS) driver width is increased, the victim line gets more prone to crosstalk noise. The crosstalk magnitude level increases alarmingly as driver width is increased, because the driver resistance decreases, which in turn increases the current driving capability of driver.
Originality/value
While designing coupled interconnects, driver width and line resistance play an important role in deciding the crosstalk level. An interconnect designer often increases driver width and reduces line resistance for achieving lower propagation delays. This effort may result in higher crosstalk noise in coupled interconnect. Therefore, a designer should be concerned simultaneously for crosstalk noise while reducing delays.
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B.K. Kaushik, S. Sarkar, R.P. Agarwal and R.C. Joshi
To analyze the effect of voltage scaling on crosstalk.
Abstract
Purpose
To analyze the effect of voltage scaling on crosstalk.
Design/methodology/approach
Voltage scaling has been often used for reducing power dissipation of CMOS driven interconnects. An undesired effect observed due to voltage scaling is increase in propagation delay. Thus, a trade off lies between power dissipation and propagation delay with voltage scaling. However, voltage scaling can result in overall reduction of power delay product. Therefore, their lies an optimized supply voltage where‐in power dissipation and propagation delay can be optimized. Many of the previous researches have discussed about power dissipation and propagation delay only with voltage scaling. This paper for first time shows the effect on crosstalk in voltage scaled interconnects. In this paper, we primarily study the noise for an input signal having transition time of 50 ps. The simulations are run for interconnect length of 2 and 4 mm. These parameters are varied for four different cases of stimulations to aggressor and victim lines viz. VA (input at aggressor node A) and VB (input at victim node B) switching in same direction; VA is switching and VB at static low; VA and VB are switching in opposite direction; VA is switching and VB at static high.
Findings
It is quite encouraging to observe that irrespective of interconnect length and technology node used, an optimized voltage scaling reduces normalized crosstalk level.
Originality/value
Voltage scaling can be effectively used for crosstalk reduction by the new era VLSI interconnect designers. This paper shows simulation results for crosstalk reduction in different nano‐sized CMOS driven RLC‐modeled interconnects.
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Brajesh Kumar Kaushik, Sankar Sarkar, R.P. Agarwal and R.C. Joshi
To analyze factors affecting crosstalk and to study the effect of repeater insertion on crosstalk, power dissipation and propagation delay.
Abstract
Purpose
To analyze factors affecting crosstalk and to study the effect of repeater insertion on crosstalk, power dissipation and propagation delay.
Design/methodology/approach
Crosstalk is effected by transition time of the signal; length of interconnect; distance between interconnects; size of driver and receiver; pattern of input; direction of flow of signal; and clock skew. This work is based on simulating interconnects with parameters obtained from 0.13 μm process. The types of noise addressed are overshoot; undershoot and oscillatory noise. Further, to study the effect of repeater insertion on crosstalk, repeaters are inserted in one line, i.e. line A only. Uniform repeaters varying in number from 1 to 60 are each of size Wn=3.9 μm and Wp=7.8 μm. Both lines A and B are terminated by a capacitive load of 5 fF. A crosstalk noise effect is measured for line A loaded with repeaters. The number of repeater is varied for four different cases of stimulations to both lines viz. input to line A, i.e. VA switching from low to high; input to line B, i.e. VB switching from low to high; input to line A i.e VA switching from low to high; input to line B, i.e. VB switching from high to low; VA switching from high to low and VB at static low; VA switching from high to low and VB at static high.
Findings
This paper shows the prominent factors such as edge rate, length and pattern of inputs affecting the noise. It is observed that presence of inductive effects can seriously hamper the functioning of the chip. This paper further reveals that repeater insertion not only reduces the propagation delay but also crosstalk levels for coupled lines. Repeaters can be efficiently utilized for reduction of propagation delay and crosstalk noise at a trade of marginal increase in power dissipation. The power‐delay‐crosstalk‐product (PDCP) criterion is introduced as an efficient technique to insert repeater in coupled interconnects. Based on PDCP a reduction in crosstalk of about 60 times and delay of 4.2 percent is achieved at trade of 13.2 percent increase in power dissipation in comparison to PDP.
Originality/value
The PDCP criterion is introduced as an efficient technique to insert repeater in coupled interconnects. Instead of PDP criterion, PDCP criterion is best suited for determination of optimum number of repeaters for overall minimization of delay, power and crosstalk.
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Prafullata Kiran Auradkar, Atharva Raykar, Ishitha Agarwal, Dinkar Sitaram and Manavalan R.
The purpose of this paper is to convert real-world raster data into vector format and evaluate loss of accuracy in the conversion process. Open-source Geographic Information…
Abstract
Purpose
The purpose of this paper is to convert real-world raster data into vector format and evaluate loss of accuracy in the conversion process. Open-source Geographic Information System (GIS) is used in this process and system resource utilizations were measured for conversion and accuracy analysis methods. Shape complexity attributes were analyzed in co-relation to the observed conversion errors.
Design/methodology/approach
The paper empirically evaluated the challenges and overheads involved in the format conversion algorithms available in open-source GIS with real-world land use and land cover (LULC) map data of India. Across the different LULC categories, geometric errors of varying density were observed in Quantum GIS (QGIS) algorithm. Area extents of original raster data were compared to the vector forms and the shape attributes such as average number of vertices and shape irregularity were evaluated to explore the possible correlation.
Findings
The results indicate that Geographic Resources Analysis Support System provides near error-free conversion algorithm. At the same time, the overall time taken for the conversion and the system resource utilizations were optimum as compared to the QGIS algorithm. Higher vector file sizes were generalized and accuracy loss was tested.
Research limitations/implications
Complete shape complexity analysis could not be achieved, as the weight factor for the irregularity of the shapes is to be varied based on the demography as well as on the LULC category.
Practical implications
Because of the higher system resource requirements of topological checker tool, positional accuracy checks for the converted objects could not be completed.
Originality/value
This paper addresses the need of accuracy analysis of real-world spatial data conversions from raster to vector format along with experimental setups challenges and impact of shape complexity.
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Bikramaditya Das, Bidyadhar Subudhi and Bibhuti Bhusan Pati
The purpose of this paper is to propose development of a formation control algorithm by employing a nonlinear observer for compensating the delay in the sensor signal transmission…
Abstract
Purpose
The purpose of this paper is to propose development of a formation control algorithm by employing a nonlinear observer for compensating the delay in the sensor signal transmission to the controller arising due to packet dropout in acoustic medium.
Design/methodology/approach
A robust control law is developed using the sliding mode approach integrated with a communication consensus algorithm for achieving cooperative motion of acoustic underwater vehicles in a group ensuring the transfer of information among the AUVs. In acoustic medium, inter-vehicle communication is challenging for a group of AUVs deployed in formation because underwater channel encounter a number of constraints such as low data rate, packet delays and dropouts.
Findings
It is observed that the sliding mode control-unscented Kalman filter formation control exhibits superior control performance such as mitigating larger initial error of estimation and removing the use of the Jacobian matrices among the three controllers developed. The proposed nonlinear observer estimates the un-measureable states such as position in x, y and z-axes, heading, rudder and sturn angle, needed for generating the formation control. A simulation setup is realized to demonstrate the performance of the proposed observer-based formation controller. Simulations were performed in MATLAB and the obtained results are analysed and compared which envisage that the proposed control algorithm provides efficient formation control under the acoustic communication constraints.
Originality/value
Development of observer for achieving formation control of AUVs in underwater area – common reference velocity and error signals being available to all cooperating AUVs – UKO performs better based on initial error estimation and tracking the same path in shallow water area.
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Milad Soleimani and Mohsen Shahandashti
Bioconcrete is widely believed to be environmentally beneficial over conventional concrete. However, the process of bioconcrete production involves several steps, such as waste…
Abstract
Purpose
Bioconcrete is widely believed to be environmentally beneficial over conventional concrete. However, the process of bioconcrete production involves several steps, such as waste recovery and treatment, that potentially present significant environmental impacts. Existing life-cycle assessments of bioconcrete are limited in the inventory and impact analysis; therefore, they do not consider all the steps involved in concrete production and the corresponding impacts. The purpose of this study is to extensively study the cradle-to-gate environmental impacts of all the production stages of two most common bioconcrete types (i.e. sludge-based bioconcrete and cement kiln dust-rice husk ash (CKD-RHA) bioconcrete) as opposed to conventional concrete.
Design/methodology/approach
A cradle-to-gate life-cycle assessment process model is implemented to systematically analyze and quantify the resources consumed and the environmental impacts caused by the production of bioconcrete as opposed to the production of conventional concrete. The impacts analyzed in this assessment include global warming potential, ozone depletion potential, eutrophication, acidification, ecotoxicity, smog, fossil fuel use, human toxicity, particulate air and water consumption.
Findings
The results indicated that sludge-based bioconcrete had higher levels of global warming potential, eutrophication, acidification, ecotoxicity, fossil fuel use, human toxicity and particulate air than both conventional concrete and CKD-RHA bioconcrete.
Originality/value
The contribution of this study to the state of knowledge is that it sheds light on the hidden impacts of bioconcrete. The contribution to the state of practice is that the results of this study inform the bioconcrete production designers about the production processes with the highest impact.
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Nurizaty Zuhan, Mariyana Aida Ab Kadir, Muhammad Najmi Mohamad Ali Mastor, Shek Poi Ngian and Abdul Rahman Mohd. Sam
Concrete-filled steel hollow (CFHS) column is an innovation to improve the performance of concrete or steel column. It is believed to have high compressive strength, good…
Abstract
Purpose
Concrete-filled steel hollow (CFHS) column is an innovation to improve the performance of concrete or steel column. It is believed to have high compressive strength, good plasticity and is excellent for seismic and fire performance as compared to hollow steel column without a filler.
Design/methodology/approach
Experimental and numerical investigation has been carried out to study the performance of CFHS having different concrete in-fill and shape of steel tube.
Findings
In this paper, an extensive review of experiment performed on CFHS columns at elevated temperature is presented in different types of concrete as filling material. There are three different types of concrete filling used by the researchers, such as normal concrete (NC), reinforced concrete and pozzolanic-fly ash concrete (FC). A number of studies have conducted experimental investigation on the performance of NC casted using recycled aggregate at elevated temperature. The research gap and the recommendations are also proposed. This review will provide basic information on an innovation on steel column by application of in-filled materials.
Research limitations/implications
Design guideline is not considered in this paper.
Practical implications
Fire resistance is an important issue in the structural fire design. This can be a guideline to define the performance of the CFHS with different type of concrete filler at various exposures.
Social implications
Utilization of waste fly ash reduces usage of conventional cement (ordinary Portland cement) in concrete production and enhances its performance at elevated temperature. The new innovation in CFHS columns with FC can reduce the cost of concrete production and at the same time mitigate the environmental issue caused by waste material by minimizing the disposal area.
Originality/value
Review on the different types of concrete filler in the CFHS column. The research gap and the recommendations are also proposed.
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Eli Guinnee and Kathleen Pickering
Public and tribal libraries play an expansive role as community connectors, serving as a visible manifestation and key operator of support systems built through partnership…
Abstract
Public and tribal libraries play an expansive role as community connectors, serving as a visible manifestation and key operator of support systems built through partnership. Pandemic circumstances increased library intentional practice and innovative engagement through partnerships, making the amorphous “community” feel more real, creating access to new resources through diverse social networks while improving overall resiliency and responsiveness in a time of great need. This chapter presents outcomes from interviews with public and tribal librarians in New Mexico, a primarily rural majority-minority state in the United States. We ask, “In what ways have pandemic experiences changed our approaches to meeting information and mutualism needs in our community?” The answer is provided from a systems-based social well-being perspective, in which success is measured by the positive impact on community members’ unique capacity to live a secure and enriched life within the context of a global pandemic. Librarians shared ways in which changes in staffing and operations affected the efforts of marginalized library workers to add their voices to build new professional understandings and the potential for justice-driven approaches to resilience from a community systems-based perspective. While diverse in their responses, the common thread running throughout the narratives of the New Mexican librarians featured in this study is the role of libraries in maintaining, repairing, and enhancing the social fabric of the communities they serve.