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Specific acoustic impedance estimation;Bayesian-network-based inverse finite difference frequency domain method

Proceedings of Meetings on Acoustics 2013年第1期19卷

作者： Alexander Bockman Cameron Fackler Ning Xiang Lincoln Laboratory Massachusetts Institute of Technology Lexington MA 02421 Graduate Program in Architectural Acoust. School of Architecture Rensselaer Polytechnic Inst. Troy NY 12180 Graduate Program in Architectural Acoustics Rensselaer Polytechnic Institute 110 8th St. Greene Bldg. Troy NY 12180

Design for acoustic performance for an interior fluid domain requires accurate description of boundary materials' specific acoustic impedance. The standard approach for the estimation of this material characteristic is the two-microphone, impedance-tube method. Modifications to the processing of the sampled acoustic field have been proposed to allow for more general test geometries. While analytical methods may be applied to a small class of ideal geometries, numerical methods provide greater geometric flexibility. In general, solutions to the wave equation forward problem are found from boundary element, finite element, or finite difference methods. The inverse problem of parameter estimation is solved by evaluating accuracy of prediction of the acoustic field for given distributions of the specific acoustic impedance parameter against observed data. In this presentation a Bayesian-network sampling approach is used to estimate specific acoustic impedance of a micro-perforated panel in an impedance tube test geometry. The choice of geometry and material allow for direct comparison to the two-microphone, impedance-tube method within the appropriate frequency range, and a theoretical model for the material beyond that frequency range. The potential to extend the frequency range of operation of the impedance tube is explored. Sensitivity of the method to nuisance parameters is discussed.

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Inverse boundary and finite element formulations for the determination of high‐frequency specific impedance.

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The Journal of the Acoustical Society of America 2010年第3_SUPPLEMENT期127卷 1753-1753页

作者： Alexander Bockman Ning Xiang Graduate Program in Architectural Acoust. School of Architecture Rensselaer Polytechnic Inst. 110 8th St. Troy NY 12180 xiangn@rpi.edu

Material databases for consulting acousticians require accurate determination of specific impedance. Such data are typically gathered from the composition of data sets obtained from impedance tubes. In such tubes, the restriction of frequencies under test to those that satisfy a plane wave assumption for the tube geometry in question allows for the application of a one‐dimensional transfer function analysis. Such tubes rarely achieve accuracy at the upper and lower ends of their operating spectra. Thus, the compositing of detailed data sets may produce significant error. For researchers of wave based methods of acoustic wave propagation, this represents a severe limitation. However, these data sets may be re‐purposed for an extension of frequencies under test by the application of an inverse problem formulation of the boundary element method. The method accurately predicts data obtained within a larger impedance tube and further well extrapolates to data observed in a smaller impedance tube. Moreover, the method provides confidence in the consistency of specific impedance determination in composite data sets.

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Instrumental analysis of extended saxophone techniques for live electronics.

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The Journal of the Acoustical Society of America 2010年第3_SUPPLEMENT期127卷 2010-2010页

作者： Jonas Braasch Doug Van Nort Graduate Program in Architectural Acoust. School of Architecture Rensselaer Polytechnic Inst. 110 8th St. Troy NY 12180 braasj@rpi.edu

The development of automated music transcription systems focuses predominantly on polyphonic musical instruments. At the same time, the analysis of a monophonic instrument is usually much simpler wherein pitch, loudness, and duration of individual notes may be tracked robustly. When using extended techniques, however, many more parameters than the aforementioned three can be meaningful for the performed music. This paper explores the challenges that extended techniques pose for music recognition systems using the example of the saxophone. The goal is to correctly identify extended techniques over the whole range of the instrument, including subtones, multiphonics, growl, and other voice‐enhanced tones, as well as tones where the reed is supported by the lower teeth. The feature analysis is based on cepstrum, spectral moments, pitch, and roughness, among other features. A hidden‐Markov model is used to recognize the trajectory of the various extended techniques based on the given feature space. Finally, it is demonstrated how the recognizer can be integrated into an intelligent live electronics system to control its parameters. For example, the characteristics of a virtual acoustic enclosure (room size, reverberation time, etc.) can be adapted this way. [Work supported by NSF 0757454.]

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Importance-based sampling for porous material physical parameter estimation

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The Journal of the Acoustical Society of America 2011年第4_SUPPLEMENT期130卷 2330-2330页

作者： Cameron Fackler Ning Xiang Graduate Program in Architectural Acoust. School of Architecture Rensselaer Polytechnic Inst. 110 8th St. Troy NY 12180 facklc@rpi.edu

Bayesian inference is applied to the problem of determining the physical parameters of a rigid-frame porous material. Such materials may be characterized by the parameters of flow resistivity, porosity, and tortuosity. The Biot-Allard and Attenborough models predict the propagation of sound in rigid-frame porous materials by modeling the characteristic impedance and propagation coefficient of the material in terms of these physical parameters and a shape factor. In this work, model-based Bayesian analysis is formulated to estimate the values of these parameters from experimental measurements of the characteristic acoustic impedance or propagation coefficient of a material under test. Importance sampling and related methods are used in the parameter estimation procedure as Monte Carlo approaches to characterize the posterior probability distribution which is used to represent the likelihood of parameter values. To increase the efficiency of the sampling, adaptive strategies are employed to extend the classical importance sampling. This analysis provides quantitative estimates of the parameter values as well as estimates of the uncertainty associated with each parameter and the interrelationship between parameters.

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Parallelized finite difference time domain room acoustic simulation

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The Journal of the Acoustical Society of America 2012年第3_SUPPLEMENT期132卷 1880-1880页

作者： Cameron Fackler Jonathan Botts Ning Xiang Graduate Program in Architectural Acoustics School of Architecture Rensselaer Polytechnic Institute 110 8th St Greene Building Troy NY 12180facklc@rpi.edu

A parallelized room acoustics simulator based on the finite difference time domain (FDTD) method is developed, utilizing a Blue Gene/L supercomputer. Wave-based methods such as FDTD are desirable for use in room acoustics simulations since they account for effects such as diffraction and interference. However, such methods require large amounts of computational power and memory, especially when simulating large volumes or high frequencies. To utilize the power of modern computing systems and move toward large-scale simulations of realistic concert halls, a parallel FDTD implementation is written in the C++ programming language with the Message Passing Interface (MPI) library. The volume to be simulated is partitioned into blocks, which efficiently update shared interfaces between nearest neighbors using the Blue Gene architecture's point-to-point communication network. Several compact explicit FDTD schemes are compared using simulations of various spatial volumes, executed on varying numbers of processors. The use of a Blue Gene/L supercomputer demonstrates substantial speedup over an equivalent serial implementation.

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A binaural localization model that resolves front‐back confusions through head movements.

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The Journal of the Acoustical Society of America 2010年第3_SUPPLEMENT期127卷 1886-1886页

作者： Jonas Braasch John T. Strong Ning Xiang Graduate Program in Architectural Acoust. School of Architecture Rensselaer Polytechnic Inst. 110 8th St. Troy NY 12180 braasj@rpi.edu

It is well known that head movements are instrumental in resolving front/back confusions in human sound localization. A mechanism for a binaural model is proposed here to extent current cross‐correlation models to compensate for head movements. The algorithm tracks sound sources in the head‐related coordinate system (HRCS) as well as in the room‐related coordinate system (RRCS). It is also aware of the current head position within the room. The sounds are positioned in space using an HRTF catalog at 1 deg azimuthal resolution. The position of the sound source is determined through the inter‐aural cross‐correlation (IACC) functions across several auditory bands, which are mapped to functions of azimuth and superposed. The maxima of the cross‐correlation functions determine the position of the sound source, but unfortunately, usually two peaks occur—one at or near the correct location and the second one at the front/back reversed position. When the model is programed to virtually turn its head, the degree‐based cross‐correlation functions are shifted with current head angle to match the RRCS. During this procedure, the IACC peak for the correct hemisphere will prevail if integrated over time for the duration of the head movement, whereas the front/back reversed peak will average out.

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A Benchmark Model for Predicting Building Energy and Daylight Performance in The Early Phase of Design Utilizing Parametric Design Exploration

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IOP Conference Series: Earth and Environmental Science 2021年第1期830卷

作者： Rendy Perdana Khidmat Hiroatsu Fukuda Kustiani Andi Prasetiyo Wibowo Fukuda Laboratory Graduate School of Environmental Engineering The University of Kitakyushu Kitakyushu Japan Architecture Study Program Department of Infrastructure and Regional Technology Institut Teknologi Sumatera Lampung Indonesia Department of Architecture Faculty of Engineering Bandar Lampung University Lampung Indonesia. Department of Architecture Universitas Atma Jaya Yogyakarta Yogyakarta Indonesia.

Along with the enormous impact on computational development in architecture and urban design, the way in approaching the built environment is shifting and intended to look closer to performance and evidence-based design. This development holds promise in handling complex computation to approach desired targeted design goals. However, the implementation of form-finding and design performance optimization still lacks, particularly in Japan's sub-tropical climate. This paper describes the parametric design and design exploration process's implementation through the generative algorithm platform to develop a benchmark model to predict building energy and daylight performance and find possible design solutions from the iteration process during the early phase of the design process. The variables incorporated related to the glazing ratio, the length of the overhang, and building orientation. Grasshopper, a parametric-based plugin that works in Rhinoceros, is used to arrange a parametric definition for the overall experiment. The tools used to investigate the environmental analysis and energy consumption are Ladybug and Honeybee, and the exploration process will be conducted using Design Explorer. The context will be situated in Orio district and uses the EPW file of Kitakyushu city, Fukuoka, Japan. The results of this research furthermore can potentially be a comparison for more dynamic factors.

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Arsenal ship program certification plan

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NAVAL ENGINEERS JOURNAL 1998年第1期110卷 249-261页

作者： Arntson, S Lind, W Turner, JJ Blaiklock, WC Tedesco, M Stephen G. Arntson is an independent consultant. A degree Naval Architect he has over 38 years of experience in the design construction and maintenance of surface ships. His experience includes 28 yeus with the Naval Sea Systems Command Naval Ship Engineering Centerl Bureau of Ships specializing in the structural design of Naval surface ships and 7 years with ABS Specializing in the application of commercial ship design practices. Most recently he worked with both NASSCO and ABS MZ the Arsenal Ship Program. Steve was very active with the Ships Structure Committee in developing R&D programs for ship structure and he is a member of the ASNE Journal Committee. Steve received a BS in Mechanical Engineering (Naval Architecture Option) from Virginia Polytechnic Institute in 1964. He is a member of the ASNE TAU BETA PI PI TAU SIGMA and PHI KAPPA PHI. William 1. Lind joined ABS in 1992 after ten years with Sparkman and Stephens Inc. He is currently ABS Amekas Manager of Engineering jm New Orleans and Cleveland. Both ofices conduct plan reviews for militavy commercial and private marine craft fm self-propelled vessels under 300 feet in length and bargus unlimited in length. As Vice-Chaimn ojthe Western Rivers Technical Committee Great Lakes Technical Committee and the Small Vessel Committee Bill participated in the writing of the 1997 ABS Guide for Building and Classing High Speed Craft and the 1997 ABS Rules for Building and Classing Steel Vessels Under 9OM. Bill received an MBA from Florida Atlantic University in 1995 a BS in Mechanical Engineering from New York Institute of Technology in 1986 and a BA in Histoy from Colgate University in 1976. He is Chaimn of SNAME HS-9 Composite Panel Testing & Fire Protection and a member of ASNE. John J. Turner is Senior Vice President of SYNTEK Technologies Inc. in Arlington Virginia. SYNTEK specializes in activities of a highly technical nature supporting both industry and government in domestic and international markets. He is a registered Professional Engineer

The Defense Advanced Research Project Agency (DARPA), in conjunction with the U.S. Navy, initiated a research program for the design and construction of a distinctive warship for the 21st century known as the Arsenal Ship. By using an innovative development and acquisition approach it was hoped to streamline the procurement process and reduce costs. In an environment where budgets are being cut, both industry and Government were challenged to develop, design, and produce the innovative ship and related mission systems to meet specific performance capabilities within strict affordability constraints. A key element of this innovative acquisition approach was a new certification scheme designed to replace the traditional test and evaluation (T&E) and acceptance process. The purpose of this paper is to describe the development of the certification plan during Phase LI of the Arsenal Ship program by the American Bureau of Shipping and the contending Shipyard teams, and to discuss the potential benefits of this alternative certification approach. Although the Arsenal Ship program was canceled late in 1997, insight derived from the exploration of new certification concepts could benefit future design and building programs.

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Developing Tourism Attractions Based on Ecotourism in Aek Nauli Indonesia

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IOP Conference Series: Earth and Environmental Science 2020年第1期452卷

作者： N Ginting E Triska Architecture Department Faculty of Engineering Universitas Sumatera Utara Medan 20155 Indonesia Post Graduate Program of Architecture Faculty of Engineering Universitas Sumatera Utara Medan 20155 Indonesia Toba Lake and Sustainable Tourism Working Group Universitas Sumatera Utara Medan 20155 Indonesia

Tourism development is needed because tourism can increase an income in a destination. Ecotourism is a new type of tourism that responsible towards nature, community, and the environment. Ecotourism draws more tourist's interest because besides giving natural tourism experience, they can learn to conserve the nature and involve with the community. Aek Nauli Natural Forest has been opened for public since 2011. However, the tourism is not developing despite of its attraction's potential. This research is focusing on natural attraction as one of the elements of tourism attraction. The aim of this research is to find tourist attractions that have the potential to be developed based on ecotourism in Aek Nauli. This research uses a qualitative method by conducting observation and in-depth interview with key respondents. The result of this research is a concept of potential attraction development based on ecotourism in Aek Nauli.

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The uniqueness of the environmental aspects of sustainable tourism on Samosir Island

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IOP Conference Series: Earth and Environmental Science 2020年第1期452卷

作者： Nurlisa Ginting Michaela Architecture Department Faculty of Engineering Universitas Sumatera Utara Medan 20155 Indonesia Post Graduate Program of Architecture Faculty of Engineering Universitas Sumatera Utara Medan 20155 Indonesia Toba Lake and Sustainable Tourism Working Group Universitas Sumatera Utara Medan 20155 Indonesia

The dominance of economic values in the tourism development has caused the decline of other important values, thus make the application of sustainability concept is crucial. As part of Indonesia's priority destinations, this concept is also needed to be applied in Samosir Island. In other hand as a tourism destination, a place must have distinctiveness to differentiate it from other places because tourism is fundamentally a recreational product based on place phenomenon. The research is a study of the value of uniqueness on the environmental elements of sustainable tourism in Samosir Island, North Sumatra, Indonesia. The research used mixed methods where questionnaires were distributed to 105 respondents, field observation was conducted, and in-depth interviews were held with six key informants. The result shows that the existence of the traditional building has a great influence towards the physical integrity of the tourist while the diverse cultural activities in the areas required appropriate strategies in enhancing and supporting the environmental elements of sustainable tourism.

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