Low complexity hybrid layered tabu-likelihood ascent search for large MIMO detection with perfect and estimated channel state information

Sourav Chakraborty,Nirmalendu Bikas Sinha,Monojit Mitra 한국전자통신연구원 2023 ETRI Journal Vol.45 No.3

In this work, we proposed a low-complexity hybrid layered tabu-likelihood ascent search (LTLAS) algorithm for large multiple-input multiple-output (MIMO) system. The conventional layered tabu search (LTS) approach involves many partial reactive tabu searches (RTSs), and each RTS requires an initialization and searching phase. In the proposed algorithm, we restricted the upper limit of the number of RTS operations. Once RTS operations exceed the limit, RTS will be replaced by low-complexity likelihood ascent search (LAS) operations. The block-based detection approach is considered to maintain a higher signal-to-noise ratio (SNR) detection performance. An efficient precomputation technique is derived, which can suppress redundant computations. The simulation results show that the bit error rate (BER) performance of the proposed detection method is close to the conventional LTS method. The complexity analysis shows that the proposed method has significantly lower computational complexity than conventional methods. Also, the proposed method can reduce almost 50% of real operations to achieve a BER of 10^-3.

Wind induced pressure on 'Y' plan shape tall building

Sourav Mukherjee,Sujit Kumar Dalui,Souvik Chakraborty,Ashok Kumar Ahuja 한국풍공학회 2014 Wind and Structures, An International Journal (WAS Vol.19 No.5

This paper presents a comprehensive study of pressure developed on different faces of a 'Y' plan shape tall building using both numerical and experimental means. The experiment has been conducted in boundary layer wind tunnel located at Indian Institute of Technology Roorkee, India for flow condition corresponding to terrain category II of IS:875 (Part 3) – 1987, at a mean wind velocity of 10 m/s. Numerical study has been carried out under similar condition using computational fluid dynamics (CFD) package of ANSYS, namely ANSYS CFX. Two turbulence models, viz., k-ε and Shear Stress Transport (SST) have been used. Good conformity among the numerical and experimental results have been observed with SST model yielding results of higher magnitude. Peculiar pressure distribution on certain faces has been observed due to interference effect. Furthermore, flow pattern around the model has also been studied to explain the phenomenon occurring around the model.

Wind induced pressure on 'Y' plan shape tall building

Mukherjee, Sourav,Chakraborty, Souvik,Dalui, Sujit Kumar,Ahuja, Ashok Kumar Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.19 No.5

This paper presents a comprehensive study of pressure developed on different faces of a 'Y' plan shape tall building using both numerical and experimental means. The experiment has been conducted in boundary layer wind tunnel located at Indian Institute of Technology Roorkee, India for flow condition corresponding to terrain category II of IS:875 (Part 3) - 1987, at a mean wind velocity of 10 m/s. Numerical study has been carried out under similar condition using computational fluid dynamics (CFD) package of ANSYS, namely ANSYS CFX. Two turbulence models, viz., $k-{\varepsilon}$ and Shear Stress Transport (SST) have been used. Good conformity among the numerical and experimental results have been observed with SST model yielding results of higher magnitude. Peculiar pressure distribution on certain faces has been observed due to interference effect. Furthermore, flow pattern around the model has also been studied to explain the phenomenon occurring around the model.

Wheat and Cassava Flour-Based Composite Formulation of Cookies: Optimization of the Ingredient’s Level by Simplex Lattice Design and Sensory Evaluation Using Fuzzy Logic

Singamayum Khurshida,Chakraborty Sourav,Das Manas Jyoti,Sit Nandan,Deka Sankar Chandra 한국농업기계학회 2021 바이오시스템공학 Vol.46 No.1

Purpose The present study aims to develop value added cookies using composite formulation of wheat and cassava flour using simplex lattice mixture design and sensory evaluation by applying fuzzy logic approach. Methods Based on the simplex lattice mixture design, optimized formulations of the cookies using wheat flour, dry chips flour, and fermented cassava flour were developed. The impacts of the composite flour on different quality traits of the cookies specifically rheology, color, texture, and sensory properties were studied. Results The optimized formulations of the cookies were determined as wheat flour of 77.50%, dry chips flour of 16.67%, and fermented cassava flour of 5.83% of total flour. The responses under this formulation were color value (L* value) of 67.23, the maximumbreaking strength of 23.55 N, and loss tangent of 0.29. Investigation of the rheological properties based on loss tangent values demonstrated solid elastic behavior of the cookie’s dough. Furthermore, sensory evaluation by applying fuzzy logic approach revealed cookies prepared with the optimum formulation as the best sample based on appearance, aroma, taste, and texture. Conclusions The present study has the credentials to support that the developed composite flour-based cookies are the effectual alternative of accessible bakery items as evidenced by the results with improved quality properties.

Compaction and unconfined compressive strength of sand modified by class F fly ash

Bera, Ashis K.,Chakraborty, Sourav Techno-Press 2015 Geomechanics & engineering Vol.9 No.2

In the present investigation, a series of laboratory compaction and unconfined compressive strength laboratory tests has been performed. To determine the effect of compaction energy, type of sand, and fly ash content, compaction tests have been performed with varying compaction energy ($2700kJ/m^3-300kJ/m^3$), types of sand, and fly ash content (0% to 40%) respectively. From the experimental results, it has been found that the optimum value of unconfined compressive strength obtained for a sand-fly ash mixture comprised of 65% sand and 35% fly ash. Based on the data obtained in the present investigation, a linear mathematical model has been developed to predict the OMC of sand-fly ash mixture.

An efficient vibration control strategy for reliability enhancement of HAWT blade

M. Mohamed Sajeer,Arunasis Chakraborty,Sourav Das 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.26 No.6

This paper investigates the safety of the wind turbine blade against excessive deformation. For this purpose, the performance of the blade in the along-wind direction is improved by longitudinal stiffener made of shape memory alloy. The rationale behind the selection of this smart material is due to its ability to offer excellent thermo-mechanical behaviour at low strain. Here, Liang-Roger model is adopted for vibration control, and the super-elastic effects are utilised for blade stiffening. Turbulent wind fields are generated at the hub height using TurbSim and the corresponding loads are evaluated using blade element momentum theory. An efficient switching algorithm is developed along with performance curves that enable the designer to select an optimal mode of heating depending upon the operational scenario. Numerical results presented in this paper clearly demonstrate the performance envelope of the proposed stiffener and its influence on the reliability of the blade.

Application of Instant Decompression-Assisted Steam Curing for Improving Turmeric (Curcuma longa L.) Powder Quality

Gautam Swapnil Prashant,Chakraborty Sourav,Narjary Aparna,Deka Jolly,Hazarika Manuj Kumar 한국농업기계학회 2021 바이오시스템공학 Vol.46 No.3

Purpose The objective of the investigation was to develop turmeric powder with improved quality using an instant decompression-assisted steam curing (IDASC) process. Method The IDASC treatment was administered on peeled turmeric slices in the ICPD treatment chamber, which was further followed by hot air drying of the treated slices (IDASC-HAD). The process conditions, namely, treatment pressure (TP), treatment time (TT) and temperature of drying (TD) were optimized for the minimization of hot air drying time (DT) and maximization of the yellowness value (YV) and curcumin content (CC) of the turmeric powder, by the application of an approach which combines the benefits of particle swarm optimization (PSO) with the response surface methodology (RSM). Microstructure of the IDASC-HAD-treated turmeric slices were observed based on scanning electron microscopy (SEM) image. Turmeric powder obtained by the IDASC-HAD approach was compared with the conventional product for various functional properties. Results The best quality turmeric powder with DT of 325 min and YVand CC of 60 and 5.05%, respectively, was obtained under the optimum process conditions of the IDASC-HAD process, namely, TP of 3 atm, TT of 50 s and TD of 57 °C. The IDASCHAD- based turmeric powder samples exhibited higher values of 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), total phenolic content (TPC) and total flavonoid content (TFC) as compared to the conventionally produced ones. The improvements in the particle size and micro-structural characteristics were justified from the results of SEM. Conclusion Turmeric powder produced by the IDASC-HAD method as applied to turmeric slices can be asserted as a product with improved antioxidant properties, which may have application in development of beverages with potential health benefits.

Metabolomics affirms traditional alcoholic beverage raksi as a remedy for high-altitude sickness

Soumya Majumder,Arindam Ghosh,Sourav Chakraborty,Sumedha Saha,Malay Bhattacharya 한국식품연구원 2021 Journal of Ethnic Foods Vol.8 No.-

Raksi, a fermented distilled alcoholic beverage, is an ethnic drink consumed in high altitude regions of Singalila Ridge of the Himalayas and in adjoining high altitude places in Nepal, northern and north eastern part of India and Tibetan plateau. Like jaanr, tongba, nigar, chhyang, and other fermented ethnic beverages, raksi is considered as an element of ethnopharmacology of high altitude with claims of medicinal properties. An ethnobiological survey was done in the study area prior to collection and identification of raksi samples. In this research, two raksi samples (khokim raksi and chimphing raksi) of Singalila Ridge of the Himalayas were investigated by metabolite profiling using gas chromatography-mass spectrometry analysis. Results of the experiment showed presence of several respiratory protective, cardioprotective, neuroprotective, anti-inflammatory, and antioxidant components which have properties to prevent various high altitude illnesses. Moreover, large quantities of bioactive terpenoids, fatty acid derivatives, coumarins, and peptides were detected whose chemotaxonomy and biosynthesis pathways were further studied. This metabolomics investigation not only affirmed Raksi as a remedy for high-altitude sickness but also helped in understanding the importance of this type of ethnic foods in high altitude ethnoecology. This research on raksi in the fields of ethnobiology and metabolomics is a cumulative approach which has opened the door for in-depth investigations on similar ethnic foods. However, further experiments on raksi are surely needed in ethnobiology, microbiology, biochemistry, and food technology.