Performance Analysis of Uplink Cognitive Radio Transmission based on Overloaded MC-DS-CDMA

Sundararajan, Mohandass,Govindaswamy, Umamaheswari The Institute of Electronics and Information Engin 2014 IEIE Transactions on Smart Processing & Computing Vol.3 No.4

This paper reports a cognitive radio network architecture based on overloaded multicarrier direct sequence code division multiple access (O-MC-DS-CDMA). The O-MC-DSCDMA technique combines CDMA with a multicarrier modulation technique to overcome the channel fading effects. In this technique, secondary users are enabled to share the available bandwidth with the existing primary users. Two sets of orthogonal Gold codes are used to support the primary and secondary users simultaneously. The orthogonality between the spreading codes is lost due to the non-zero cross correlation between the codes and the timing synchronization error in the uplink transmission, which causes interference between primary and secondary users. This paper proposes two modified hybrid parallel/successive interference cancellation techniques for primary and secondary user base station receivers with multiple antennas to suppress the interference among users. Interference among the same group of users is cancelled by parallel interference cancellation and the interference among groups is cancelled using successive interference cancellation. The simulation results confirmed that the proposed modified interference cancellation techniques show better BER performance over conventional interference cancellation techniques.

Novel 1-(4-substituted benzylidene)-4-(1-(substituted methyl)-2,3- dioxoindolin-5-yl)semicarbazide derivatives for use against Mycobacterium tuberculosis H37Rv (ATCC 27294) and MDR-TB strain

Sundararajan Raja,Chinnasamy Rajaram Prakash 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.4

A series of eighteen new 1-(4-substituted benzylidene)-4-(1-(substituted methyl)-2,3-dioxoindolin-5-yl)semicarbazidederivatives were designed, synthesized andcharacterized by spectral and elemental analyses. Thederivatives were screened in vitro for antimicrobial activityagainst Mycobacterium tuberculosis H37Rv (ATCC 27294)and MDR-TB strains. The activity was expressed as theminimum inhibitory concentration in lg/mL. Among thetested compounds 7j, 7m, 7o and 7q possesses equipotentactivity as standard drug Isoniazid against MTB while 7mand 7q exhibited higher activity against MDR-TB strainwhen compared with both the reference drugs isoniazidand rifampicin. Basic structure activity relationships arepresented.

Exogenous supplementation with sodium nitroprusside, a nitric oxide donor, mitigates the effects of salinity in Abelmoschus esculentus L. seedlings

Sundararajan Sathish,Shanmugam Rekha,Sivakumar Hari Priya,Ramalingam Sathishkumar 한국원예학회 2022 Horticulture, Environment, and Biotechnology Vol.63 No.3

We investigated the protective role of the nitric oxide donor sodium nitroprusside (SNP) in ameliorating the detrimental effects of salinity in in vitro-grown okra (Abelmoschus esculentus L.). Okra seedlings were subjected to salinity treatments at three different NaCl concentrations (100, 150, and 200 mM), which caused a significant reduction in germination rate, shoot and root lengths, and shoot fresh weight (FW) and dry weight (DW). Further, salinity exposure had detrimental effects on the total chlorophyll content, proline content, electrolyte leakage (EL), relative water content (RWC), malondialdehyde (MDA) accumulation, and nitrate reductase activity in the seedlings. However, supplementation with SNP significantly improved the plant growth parameters including shoot and root lengths, shoot FW and DW, chlorophyll content, and proline accumulation. Among the tested concentrations, SNP at 100 and 150 µM significantly reduced the H2O2 content, MDA accumulation, and EL, and increased the RWC under salinity stress. SNP supplementation also resulted in increased activity of the antioxidant enzymes catalase, peroxidase, and superoxide dismutase. Our results revealed the positive effects of SNP in alleviating salt stress through enhanced activity of antioxidant enzymes and osmotic adjustment, which can be explored and applied for better growth and yield performance, especially in regions with high salinity.

Tissue Culture and Agrobacterium-Mediated Genetic Transformation Studies in Four Commercially Important Indica Rice Cultivars

Sathish Sundararajan,Balaji Sivaraman,Venkatesh Rajendran,Sathishkumar Ramalingam 한국작물학회 2017 Journal of crop science and biotechnology Vol.20 No.3

Agrobacterium-mediated genetic transformation method for recalcitrant indica rice cultivars. For this, mature seeds of commercially important indica rice varieties, ASD16, ADT43, IR 64, and Pusa Basmati were cultured on MS and N6 medium supplemented with 2 mg l-1 2, 4-D + 30 g l-1 sucrose. The calli grown in N6 medium showed better friability and embryogenic response. Out of the four varieties tested, ASD16 and IR64 showed better callusing and embryogenic capacity as compared to ADT43 and Pusa Basmati. For genetic transformation studies, embryogenic calli of all the cultivars were co-cultivated with the Agrobacterium tumefaciens strain LBA 4404 harboring the binary vector pCambia 1305.1 with GUS gene. GUS assay was performed for the putative transformed calli and its activity was found to be qualitatively higher in ASD16 and IR64 than the other two varieties. The best responsive ASD16 transformed calli was regenerated and the putative transgenic lines were regenerated. ASD16 transformed calli were confirmed by GUS assay. PCR analysis confirmed the presence of both GUS and HPT genes in ASD16 transgenic lines.

Effect of Operating Conditions on Condition Monitoring of Power Electronic Converters and a Review of Normalization Schemes

Prasanth Sundararajan,Marif Daula Siddique,Sanjib Kumar Panda 전력전자학회 2023 ICPE(ISPE)논문집 Vol.2023 No.-

Power electronic converters have changed the way in which electrical energy is converted from one form to another form. They are widely used in many critical applications because of their efficient and precise control of electric power. However, they suffer from failures which may lead to loss of revenue and even threaten the safety of human life in certain safety critical applications. Power devices and capacitors are the major sources of failures in power converter. Therefore, condition monitoring methodologies are developed for these components and a vast majority of those methods are based on failure precursor parameters like on-state voltage drop, case temperature, capacitance, equivalent series resistance (ESR), etc. These failure precursor parameters are sensitive to operating conditions which makes normalization techniques that eliminate the influence of operating conditions very important in condition monitoring methodologies. However, this normalization process is often overlooked during implementation. Therefore, this paper presents a review of normalization schemes and analyses the effect of operating conditions on some of the most widely used failure precursor parameters.

Metformin Reduces the Progression of Atherogenesis by Regulating Sestrin2-mTOR Pathway in Obese and Diabetic Rats

Saravanakumar Sundararajan,Isaivani Jayachandran,Gautam Kumar Pandey,Saravanakumar Venkatesan,Anusha Rajagopal,Kuppan Gokulakrishnan,Muthuswamy Balasubramanyam,Viswanathan Mohan,Nagaraj Manickam 한국지질동맥경화학회 2023 지질·동맥경화학회지 Vol.12 No.3

Objective: In previous research, we found that Sestrin2 has a strong association with plasma atherogenicity and combats the progression of atherogenesis by regulating the AMPK-mTOR pathway. Metformin, an activator of AMPK, is widely used as a first-line therapy for diabetes, but its role in preventing atherosclerosis and cardiac outcomes is unclear. Hence, we aimed to assess the effect of metformin on preventing atherosclerosis and its regulatory role in the Sestrin2-AMPK -mTOR pathway in obese/diabetic rats. Methods: Animals were fed a high-fat diet to induce obesity, administered streptozotocin to induce diabetes, and then treated with metformin (150 mg/kg body weight) for 14 weeks. Aorta and heart tissues were analyzed for Sestrin2 status by western blotting and immunohistochemistry, AMPK and mTOR activities were investigated using western blotting, and atherogenicity-related events were evaluated using reverse transcription quantitative polymerase chain reaction and histology. Results: Obese and diabetic rats showed significant decrease in Sestrin2 levels and AMPK activity, accompanied by increased mTOR activity in the heart and aorta tissues. Metformin treatment significantly restored Sestrin2 and AMPK levels, reduced mTOR activity, and restored the altered expression of inflammatory markers and adhesion molecules in obese and diabetic rats to normal levels. A histological analysis of samples from obese and diabetic rats showed atherosclerotic lesions both in aorta and heart tissues. The metformin-treated rats showed a decrease in atherosclerotic lesions, cardiac hypertrophy, and cardiomyocyte degeneration. Conclusion: This study presents further insights into the beneficial effects of metformin and its protective role against atherosclerosis through regulation of the Sestrin2-AMPK-mTOR pathway.

Outside-in technique versus inside-out semitendinosus graft harvest technique in ACLR: a randomised control trial

( Silvampatti Ramasamy Sundararajan ),( Rajagopalakrishnan Ramakanth ),( Amit Kumar Jha ),( Shanmuganathan Rajasekaran ) 대한슬관절학회 2022 대한슬관절학회지 Vol.34 No.-

Background: Paraesthesia after hamstring graft harvest is a ubiquitous complication in the early post-operative period, and its correlation with vertical versus horizontal skin incision are well documented. The purpose of the study is to evaluate the incidence and extent/area of sensory loss of saphenous nerve branches occurring with the outsidein (OI) versus inside-out technique (IO) of semitendinosus graft harvest from the sartorius fascia and to determine a better method of graft harvest. Methods: Sixty patients who underwent isolated semitendinosus graft harvest during anterior cruciate ligament reconstruction (ACLR) between 2016 and 2017. Patients were randomised into two groups depending on the graft harvest technique: 30 in the OI group and 30 in the IO group. The area of sensory loss was mapped on the patients’ skin using tactile feedback from the patients at each follow-up (10 days, 1 month, 3 months, 6 months and 1 year). Then, the area of sensory changes for the infrapatellar branch (IPBSN) and sartorial branch (SBSN) of the saphenous nerve, incision length, graft harvest duration, and graft length were analysed statistically between the groups. Results: In groups 1 and 2, 18/30 (60%) and 19/30 (63%) of patients, respectively, developed sensory changes, with no significant difference between the groups (p = 0.79). Isolated SBSN and IPBSN paraesthesia occurred in 2/60 (3%) and 19/60 (32%), respectively. Combined SBSN and IPBSN paraesthesia was present in 16/60 (27%) of patients. There was no significant difference in the area of the sensory deficit between OI and IO groups on the 10th post-operative day or at 1-month, 3-month or 1-year follow-up (p = 0.723, p = 0.308, p = 0.478, p = 0.128, respectively). However, at 6-month follow-up, the area of paraesthesia was significantly higher in the IO group (p = 0.009). The length of incision and duration of graft harvest was higher in the OI group than in the IO group (p = 0.002 and p = 0.007, respectively), and the total length of the graft was greater in the IO group (p = 0.04). Conclusion: Incidence is equally distributed, area of iatrogenic saphenous nerve injury gradually decreases, and recovery is seen in the majority of the patients in both graft harvest techniques. IO graft harvesting technique is better in terms of graft harvest time and cosmetics and yields longer graft; however, area of paraesthesia, though not significant, was two-fold higher than the OI technique at 1-year follow-up. Clinical relevance: IO graft harvest technique would enable the surgeon to adopt quicker graft harvest, smaller surgical scar and lengthier graft than the OI technique. Level of evidence: Therapeutic randomised controlled prospective study, Level II.

Does Second-Generation Suspensory Implant Negate Tunnel Widening of First-Generation Implant Following Anterior Cruciate Ligament Reconstruction?

Silvampatti Ramasamy Sundararajan,Balaji Sambandam,Ajay Singh,Ramakanth Rajagopalakrishnan,Shanmuganathan Rajasekaran 대한슬관절학회 2018 대한슬관절학회지 Vol.30 No.4

Purpose: Tunnel widening following anterior cruciate ligament (ACL) reconstruction is commonly observed. Graft micromotion is an important contributing factor. Unlike fixed­loop devices that require a turning space, adjustable­loop devices fit the graft snugly in the tunnel. The purpose of this study is to compare tunnel widening between these devices. Our hypothesis is that the adjustable­loop device will create lesser tunnel widening.Materials and Methods: Ninety­eight patients underwent ACL reconstruction from January 2013 to December 2014. An adjustable­loop device was used in 54 patients (group 1) and a fixed­loop device was used in 44 patients (group 2). Maximum tunnel widening at 1 year was measured by the L’Insalata’s method. Functional outcome was measured at 2­year follow­up.Results: The mean widening was 4.37 mm (standard deviation [SD], 2.01) in group 1 and 4.09 mm (SD, 1.98) in group 2 (p=0.511). The average International Knee Documentation Committee score was 78.40 (SD, 9.99) in group 1 and 77.11 (SD, 12.31) in group 2 (p=0.563). The average Tegner­Lysholm score was 87.25 (SD, 3.97) in group 1 and 87.29 in group 2 (SD, 4.36) (p=0.987). There was no significant difference in tunnel widening and functional outcome between the groups. Conclusions: The adjustable­loop device did not decrease the amount of tunnel widening when compared to the fixed­loop device. There was no significant difference in outcome between the two fixation devices.Level of Evidence: Level 3, Retrospective Cohort

Detection of Defects on Steel Surface for using Image Segmentation Techniques

S. M. Ramesh,B. Gomathy,T.V.P.Sundararajan 보안공학연구지원센터 2014 International Journal of Signal Processing, Image Vol.7 No.5

An online surface inspection system m of hot rolled strips is introduced. This system is designed t o detect such main Surface defects on hot rolled strips as scar, scratches, pits, water drops Cracks. Cross hatchings, and so on. Multiple CCD area scan cameras are adopted to capture images of strip surface simultaneously, and all the images are processed by parallel computation system Real-time, which is supported by fast image process techniques and parallel computation techniques, in order to snap main defect regions on the surface of strips. At last, the defects will be classified to several types. The application of the system to practical production line shows that it can detect main defects of hot rolled strips more effectively than traditional method, and it is easily to be maintained.

평활화 유한요소법을 도입한 응력기반 구배 탄성론

이창계,Sundararajan Natarajan 한국전산구조공학회 2024 한국전산구조공학회논문집 Vol.37 No.3

본 논문에서는 평활화 유한요소법(Smoothed finite element method)을 도입한 응력 기반 구배 탄성론(Gradient elasticity)의 2차원 경계치 문제에 대한 연구를 수행하였다. 구배 탄성론은 기존 탄성론에서는 표현할 수 없는 미소규모의 크기 의존적인 기계적 거동을 설명하기 위해 제안되었다. 구배 탄성체론에서 고차 미분 방정식을 두 개의 2차 미분 방정식으로 분할하는 Ru-Aifantis 이론을 사용하기 때문에 평활화 유한요소법에 적용이 가능하게 된다. 본 연구에서 경계치 문제를 해결하기 위해 평활화 유한 요소 프레임워크에 스태거드 방식(Staggered scheme)을 사용하여 국부 변위장과 비국부 응력장을 평활화 영역 및 요소에서 각각 계산하였다. 구배 탄성에서 중요한 변수인 내부 길이 척도의 영향을 측정하기 위해 일련의 수치 예제를 수행하였다. 수치 해석 결과는 제안한 기법이 내부 길이 척도에 따라 균열 선단과 전위 선에 나타나는 응력 집중을 완화할 수 있음을 보여준다. This paper presents two-dimensional boundary value problems of the stress-based gradient elasticity within the smoothed finite element method (S-FEM) framework. Gradient elasticity is introduced to address the limitations of classical elasticity, particularly its struggle to capture size-dependent mechanical behavior at the micro/nano scale. The Ru-Aifantis theorem is employed to overcome the challenges of high-order differential equations in gradient elasticity. This theorem effectively splits the original equation into two solvable second-order differential equations, enabling its incorporation into the S-FEM framework. The present method utilizes a staggered scheme to solve the boundary value problems. This approach efficiently separates the calculation of the local displacement field (obtained over each smoothing domain) from the non-local stress field (computed element-wise). A series of numerical tests are conducted to investigate the influence of the internal length scale, a key parameter in gradient elasticity. The results demonstrate the effectiveness of the proposed approach in smoothing stress concentrations typically observed at crack tips and dislocation lines.