Analysis and mitigation of carrier frequency offset for uplink of OFDMA

Orthogonal Frequency Division Multiplexing (OFDM) is being used in many wireless standards because of its immunity to multipath fading, high spectral efficiency and simple implementation, making it suitable for high data rate multimedia wireless applications. One of the significant drawbacks of the OFDM is its sensitivity to Carrier Frequency Offset (CFO). CFO causes Inter Carrier Interference (ICI) between subcarriers and Multiple User Interference (MUI) at Uplink between different users. ICI and MUI at uplink cause significant degradation in the performance of the receiver, therefore, to improve the receiver performance up to acceptable level, compensation of the CFO becomes necessary. In this research, Suppression of MUI by Minimum Mean Squared Error (MMSE) Feedback Equalizer in frequency domain which was originally proposed for Single Carrier- Frequency Domain Multiple Access (SC-FDMA) has been studied for Uplink of Orthogonal Frequency Division Multiple Access (OFDMA). However, calculation of MUI power required in this algorithm for all users impose very high computational burden on the receiver. In the proposed Low Complexity MUI Suppression by MMSE Equalization for Uplink of OFDMA approximation to the calculation of MUI power is applied to reduce its complexity. Simulation result & calculated complexity show that proposed method obtains good performance with much lower complexity

Stereotactic guidance for navigated percutaneous sacroiliac joint fusion.

Arthrodesis of the sacroiliac joint (SIJ) for surgical treatment of SIJ dysfunction has regained interest among spine specialists. Current techniques described in the literature most often utilize intraoperative fluoroscopy to aid in implant placement; however, image guidance for SIJ fusion may allow for minimally invasive percutaneous instrumentation with more precise implant placement. In the following cases, we performed percutaneous stereotactic navigated sacroiliac instrumentation using O-arm® multidimensional surgical imaging with StealthStation® navigation (Medtronic, Inc. Minneapolis, MN). Patients were positioned prone and an image-guidance reference frame was placed contralateral to the surgical site. O-arm® integrated with StealthStation® allowed immediate auto-registration. The skin incision was planned with an image-guidance probe. An image-guided awl, drill and tap were utilized to choose a starting point and trajectory. Threaded titanium cage(s) packed with autograft and/or allograft were then placed. O-arm® image-guidance allowed for implant placement in the SIJ with a small skin incision. However, we could not track the cage depth position with our current system, and in one patient, the SIJ cage had to be revised secondary to the anterior breach of sacrum

Seismic Isolation of Building-Equipment System Using Modified Variable Friction Pendulum System

In this study, building-equipment system with Modified Variable Friction Pendulum System (MVFPS) is investigated under different earthquake ground excitations. Earthquake response of building-equipment system isolated with MVFPS is compared with Variable Friction Pendulum System (VFPS) and Friction Pendulum System (FPS) in order to find efficiency of MVFPS. Newmark’s linear acceleration method is used for solving governing equation of motion for building-equipment system. In this investigation, different storey buildings are considered. It is observed that MVFPS is more efficient in reducing the recoverable energy than FPS, but less efficient than VFPS. From the comparative study, it is found that FPS shows robust performance in comparison to MVFPS and VFPS in reducing equipment acceleration and displacement

Comparative Study of Seismic Analysis of Pier Supported on Pile as per IRC:6-2017 and IRC SP:114-2018

This paper depicts the study of seismic analysis of reinforced concrete bridge piers as per provisions of Indian Road Congress (IRC) guidelines. Bridges are designed having two main structural elements named – “Superstructure” and “Substructure”. Superstructure consists of deck and supporting girder/truss system below deck. Substructure includes Abutments, Piers, Portals and Foundations. Amongst these, Abutments/Piers are crucial part of bridge. Therefore, as per the seismic design philosophy, it is necessary to study the seismic behaviour of bridge piers. With the advancements in technology and subsequent researches in Infrastructure fields, IRC guidelines are updated and revised time-to-time. Introduction of IRC SP:114-2018 guideline for earthquake forces in bridges is an example of such developments. In this research, seismic analysis of Reinforced Cement Concrete (RCC) bridge pier is carried out as per provisions of prevailing guideline IRC:6-2017. Base shear value of IRC:6-2017 is compared with IRC SP:114-2018 which now supersedes seismic provisions of IRC:6-2017. For analysis, different span lengths of 25 m, 30 m and 36 m are used. To assess the impact of height of piers in earthquake analysis, various pier heights such as 10 m, 20 m and 30 m are assumed. The analysis is carried out as per Elastic Seismic Acceleration Method with consideration of different zones and importance of the bridge as per IRC guidelines. Effect of vertical ground motion is also considered in analysis. From analysis, it is observed that base shear and vertical forces have been increased remarkably as per IRC SP:114-2018 compared to IRC:6-2017

Allergic bronchopulmonary aspergillosis: the spectrum of computed tomography appearances

AbstractAlthough computed tomography (CT) of the thorax has been compared to plain chest radiography and bronchography for demonstration of central bronchiectasis (CB) in allergic bronchopulmonary aspergillosis (ABPA), the CT presentation of the disease is yet to be highlighted. With this in view, the CT appearances in 23 patients with ABPA were evaluated. The scans were assessed for bronchial, parenchymal and pleural abnormalities.Central bronchiectasis was identified in all patients, involving 114 (85%) of the 134 lobes and 210 (52%) of the 406 segments studied. Other bronchial abnormalities such as dilated and totally occluded bronchi (11 patients), air-fluid levels within dilated bronchi (five patients), bronchial wall thickening (10 patients) and parallel-line shadows (seven patients) were also observed.Parenchymal abnormalities, which had a predilection for upper lobes, included consolidation in 10 (43%) patients, collapse in four (17%) patients and parenchymal scarring in 19 (83%) patients. A total of six cavities were seen in three (13%) patients, and an emphysematous bullae was detected in one (4%) patient. The pleura was involved in 10 (43%) patients. Ipsilateral pleural effusion with collapse was observed in one patient, while in nine other patients, parenchymal lesions extended up to the pleura. Concomitant allergic Aspergillus sinusitis (AAS) was also detected in three (13%) of the 23 patients.Computed tomography of the thorax in patients with ABPA provides a sensitive method for the assessment of bronchial, parenchymal and pleural abnormalities, and should constitute a part of the diagnostic work of the disease

Design of Lean to Roof Steel Trusses with Hollow Circular tube using IS 875 (part-III):2015 & IS 800:2007

At present, SP-38:1987 is available which provides design for lean to roof type trusses and pitch roof trusses. The design of lean to roof truss has been carried out as per IS 800:1984 IS 875 (Part-III):1964. Afterwards IS 800:1984 is revised in 2007, which is based on limit state method. Also, IS 875 (Part-III) is updated in 1987 and then in 2015 considering climate changes and economical parameters. Accordingly, study has been done to revise the design of trusses given in SP-38:1987. In the present study, design and comparison of lean to roof type truss with steel circular hollow tube section have been carried out using IS 875 (Part-III):2015 and IS 800:2007 limit state method using STAAD Pro. and their results compared with SP-38:1987 results. This study includes lean to roof truss system considering different parameters like span, spacing of truss, slope of roof and wind zones with all cases of wind load. At the end, a compiled report will be prepared, which will be helpful to design engineers to provide economic, easier, faster approach for designing of steel trusses