Hardware Implementation of a Mamdani Fuzzy Logic Controller for a Static Compensator in a Multimachine Power System

A Mamdani-type fuzzy logic controller is designed and implemented in hardware for controlling a static compensator (STATCOM), which is connected to a ten-bus multimachine power system. Such a controller does not need any mathematical model of the plant to be controlled and can efficiently provide control signals for the STATCOM over a wide range of operating conditions of the power system and during different disturbances. The proposed controller is implemented using the M67 digital signal processor board and is interfaced to the multimachine power system simulated on a real-time digital simulator. Experimental results are provided, showing that the proposed Mamdani fuzzy logic controller provides superior damping compared to the conventional proportional-integral (PI) controller for both small and large scale disturbances. In addition, the proposed controller manages to restore the power system to the steady state conditions with less control effort exerted by the STATCOM, which, in turn, leads to smaller megavar rating and, therefore, less cost for the device. The matrix pencil method analysis of the damping provided by the different controllers indicates that the proposed controller provides higher damping than the PI controller and also mitigates the modes present with the conventional PI control

GenBase: A Complex Analytics Genomics Benchmark

This paper introduces a new benchmark, designed to test database management system (DBMS) performance on a mix of data management tasks (joins, filters, etc.) and complex analytics (regression, singular value decomposition, etc.) Such mixed workloads are prevalent in a number of application areas, including most science workloads and web analytics. As a specific use case, we have chosen genomics data for our benchmark, and have constructed a collection of typical tasks in this area. In addition to being representative of a mixed data management and analytics workload, this benchmark is also meant to scale to large dataset sizes and multiple nodes across a cluster. Besides presenting this benchmark, we have run it on a variety of storage systems including traditional row stores, newer column stores, Hadoop, and an array DBMS. We present performance numbers on all systems on single and multiple nodes, and show that performance differs by orders of magnitude between the various solutions. In addition, we demonstrate that most platforms have scalability issues. We also test offloading the analytics onto a coprocessor. The intent of this benchmark is to focus research interest in this area; to this end, all of our data, data generators, and scripts are available on our web site

Prediction of acoustic comfort and acoustic silence in Goan Catholic churches

Acoustic Comfort and Acoustic Silence are determinants of tranquility in a worship space. The results presented here are part of a study that investigates the behaviour of acoustically constituted worship parameters in six Catholic churches (Goa, India). Acoustic comfort is quantified through an Acoustic Comfort Impression Index which measures the net comfort induced through the optimization of the desired subjective acoustic impressions for different types of music and different music sources. Silence Factor is constituted through the normalization of equivalent noise level (LAeq) and the subjective acoustic impressions of background noise and echoes. Regression analyses of the derived acoustic parameters generate significant results. Acoustically, the Silence Factor quadratically decays with LAeq and the Acoustic Comfort Impression Index is predicted as a multiregression on the subjective acoustic impressions of balance and clarity. Architecturally, the Silence Factor linearly grows with the width of the nave (of the church) whereas, the Acoustic Comfort Impression Index does not significantly relate with any of the tested architectural parameters. Silence Factor was found to linearly grow with Acoustic Comfort Impression Index in a church. The predictability of acoustic comfort and acoustic silence from acoustic and architectural measures can be developed into a design tool for the prediction of a tranquility factor in worship spaces

Acoustic characterization of sacred music rendered by a human whistle at the Divine Providence Church in Goa, India

The human whistle is a representation of the human vocal singing. Singing (solo and congregational) is an essential component of sacred music for collective worship in a Catholic church. The acoustic characterization of sacred music is defined in this paper through a derived Acoustic Comfort Impression Index (ACII) and several Acoustic Worship Indices (AWI), namely, Subjective Sacred Factor (SSaF), Subjective Intelligibility Factor (SInF) and Subjective Si-lence Factor (SSiF). In this study, live sacred music rendered by the human whistle is compared with that by the cello, clarinet, violins and the ensemble, in the Catholic church of the Divine Providence (Goa, India). Among the signifi-cant results, ACII for the human whistle was found to be better than ACII for the musical instruments (F = 2.38, p = 0.08); this difference was more significant at the nave of the church (music source) (F = 2.94, p = 0.04) and lower at the choir loft (music source) (p = 0.21). SInF for the ensemble music was found better than SInF for human whistle (F = 3.07, p = 0.03). At the nave of the church, the SInF was found better than SSaF and SSiF (F = 4.17, p = 0.02). SSaF and SInF were equally better than SSiF at the choir loft (p = 0.02). This study opens the possibility of optimized use of the human whistle in rendering sacred music in a church

Pre-restoration subjective acoustic comfort in the Goan church of Nossa Senhora do Pilar

This study at the Church of Nossa Senhora do Pilar, built in 1613 by the Spanish Capuchos Franciscan, investigates the acoustic effect of music on the subjective comfort of a listener in a wor-ship space. The results presented describe the effect of variations in the type of music rendered (in the form of live music from the cello, clarinet and the ensemble) from two music sources sites (the nave and the choir loft, of the church) on the subjective acoustic comfort of listeners in the church of Nossa Senhora do Pilar (a significant Catholic church of Goa, India). The subjective acoustic comfort of the listeners for different music types at the two music sources was measured through the Acoustic Comfort Impression Index (ACII). This index for subjective acoustic comfort was de-rived as a difference between desirable Subjective Acoustic Impressions such as of Intimacy, En-velopment, Reverberance, Loudness, Clarity, Directionality, Balance and undesirable Subjective Acoustic Impressions such as of Echoes and of Background Noise. The derived acoustic comfort impression index also took into account the requisite of reverential awe; intelligibility for sacred speech, music, singing and the sacred silence that characterizes a worship space. Although the sa-cred music rendered by the ensemble seems to have elicited better scores of Acoustical Comfort Impression Index (ACII) among the listeners, yet there is no significant difference between the means of the listeners acoustical comfort impressions by the ensemble, cello or clarinet (p = 0.43). Amongst the two music source locations, although the Acoustical Comfort Impression Index (ACII) seems to favor the choir loft location, the music rendered therein is only 80% significantly more effective than the music rendered from the nave floor location (p = 0.20)

Relationship between acoustic worship ambience and speech intelligibility in Goa's Bom Jesus Basilica

The acoustic worship ambience in the church is defined through the derived Acoustic Worship Indices (AWI), namely Sacred Factor (SaF), Intelligibility Factor (InF) and Silence Factor (SiF). The Speech Intelligibility in the church was evaluated through RASTI tests for different sound source locations (altar [SA], pulpit [SB] and high altar [SC]) and for different postures (sitting [SIT] and standing [STAND]) and the Modified Rhyme Tests based Subjective Speech Intelligibility (SSI) scores for different source locations (SA, SB and SC) and for different languages (English [ENG] and Konkani [KONK]). SaF was found to regress significantly on SSI [SA] (R2 = 0.88) and RASTI[SIT] (R2 = 0.92); InF regressed the best on SSI[SC] (R2 = 0.84) and SSI[ENG] (R2 = 0.89) while SiF was best predicted through RASTI[STAND] (R2 = 0.93) and SSI[ENG] (R2 = 0.60). The possibility of a predictable connection between speech intelligibility and acoustic worship ambience can help enhance the liturgical functions in the church

Pre-restoration characterization of acoustical heritage of Nossa Senhora do Pilar church, Goa

The church of Nossa Senhora do Pilar built in 1613 by the Spanish Franciscan Capuchos is part of the Convento do Pilar, Goa. This diminuted sanctuary church with Rococon Mannerist features underwent repairs wherein the original lime mortar mix on its laterite stone walls was replaced by cement plaster - paint coat and ceramic tiles. Besides triggering a salt attack, the replacement of original lime mortar caused a change in the surface sound absorption values inside the church. The acoustical properties inside the church too suffered change. The restoration of this 400 year old church has begun. A method of capturing the acoustical sacred heritage of the church using objective acoustical parameters (RASTI, RT, D50, C80, TS, ITDG, G, and LAeq) and subjective acoustic impressions is presented in this study. The valuesobtained in this pre-restoration survey will be compared with those obtained through a similaracoustical characterization of the worship ambience inside the church after the inner surfaceof the walls is replastered with the original lime-mortar overcoat. This will enable a comparative explanation of the restoration of the acoustical heritage of Nossa Senhora do Pilar church

Detection of Rotor and Load Faults in BLDC Motors Operating Under Stationary and Non-Stationary Conditions

Brushless Direct Current (BLDC) motors are one of the motor types rapidly gaining popularity. BLDC motors are being increasingly used in critical high performance industries such as appliances, automotive, aerospace, consumer, medical, industrial automation equipment and instrumentation. Fault detection and condition monitoring of BLDC machines is therefore assuming a new importance. The objective of this research is to advance the field of rotor and load fault diagnosis in BLDC machines operating in a variety of operating conditions ranging from constant speed to continuous transient operation. This objective is addressed as three parts in this research. The first part experimentally characterizes the effects of rotor faults in the stator current and voltage of the BLDC motor. This helps in better understanding the behavior of rotor defects in BLDC motors. The second part develops methods to detect faults in loads coupled to BLDC motors by monitoring the stator current. As most BLDC applications involve non-stationary operating conditions, the diagnosis of rotor faults in non-stationary conditions forms the third and most important part of this research. Several signal processing techniques are reviewed to analyze non-stationary signals. Three new algorithms are proposed that can track and detect rotor faults in non-stationary or transient current signals.Ph.D.Committee Chair: Thomas G. Habetler; Committee Member: Bonnie H. Ferri; Committee Member: Christiaan Paredis; Committee Member: Deepak M. Divan; Committee Member: Ronald G. Harle