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complaint databa.se, contour prcdiction modę (FAA integrated noise model), and mapping software are also part of the system. It is cxpected that this system will be uscd to evaluate different noise descriptors against actual complaints, and to suggest improvements to noise prediction models based on geography or meteorological effeets.

9:55

2NS3. Airport noise and passivc radar monitoring for Oakland International Airport. Glenn Woodman (Oakland International Airport, #1 Airport Dr., Box 45, Oakland, CA 94621)

Airport noise has been monitored at Oakland International Airport sińce early 1970s using mobile noise-monitoring terminals for one week sampling each calendar quarter in order to meet requirements of Califomia State noise regulations. The Port of Oakland has recently installed a permanent airport noise and operations monitoring system that will enable achievement of three primary objectives: (1) gather acouslical data to meet Califomia airport noise standards, (2) remove contribution of overflights from San Francisco International Airport to Oakland's noise exposure map, and (3) develop aireraft flight track measurements and positive Identification of aireraft operators for community noise complaint resolution. Noise monitoring Systems typically are passive in measuring only noise events. Oakland's system incorporates flight operations data and passive airport surveillance radar data to provide a proactive management tool for monitoring eflfectiveness of and compliance with existing noise abatement procedures. A discussion of this system will be madę regarding its effectiveness in monitoring compliance with noise control procedures and in resolving community noise complaints.

Contributed Papers

10:20

2NS4. Intelligent aireraft noise monitoring terminals. Alan D. Wallis (Cirrus Res. Ltd., Hunmanby, England) and Robert Krug (Cirrus Res. Inc., Wauwatosa, W1 53213)

Current technology airport monitoring units using, “short as the data transfer units. allow much morę and bet ter data than has been previously possible. With very large intemal Stores, in the order of 2 megabytes, the new generation of units can simultaneously storę raw data elements and fuli environmental Information as well as each aireraft event. The paltem recognition built into the units will allow each noise monitoring terminal on the system to recognize aireraft flying over. Then, by a template comparison techniquc, it both Stores the resultant data and transfers it to a rcmote hoist for correlation. The terminal incorporates some leaming capability to inerease the “hit ratę” of recognition. Any, or all, of the acquisition parameters in each terminal can be configured from the host using a modem link. In a similar way, diagnostics can be performed from the host without visiting each terminal. Typically, 1 to 2 weeks of raw data and up to 10 000 aireraft events are stored in each terminal. This allows for unattended operations as well as security backup for the host.

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2NS5. Community aireraft noise assessment to determinc structural noise attenuation. David Draper (Dresdner, Robin & Associates, Inc., P O. Box 469, Jersey City, NJ 07302) and Henry Young (Young Environmental Sciences)

A community aireraft noise assessment was conducted for the City of New York for a major waterfront residential development (7000-8000 units) proximate to Kennedy International Airport in Quecns. The development sile lay beneath one flight path and immediately to the west of a second. Characterization of the site for aireraft noise by monitoring alone was difficult sińce the overflying runway was typically used during inclemenl wcathcr during which monitoring conditions were at their worst. Thus, a combination of monitoring and modeling was conducted to determinc the noise cxposure of proposed structures and open space. Aireraft noise was monitored at three Iocations on the site. Modeling of a worst case scenario was performed using the aireraft noise database from the integrated noise model (INM). The model was “cal-

1861 J. Acoust Soc. Am., Vol. 89, No. 4, Pt. 2. Aprii 1991 ibrated” by simulating specific aireraft flights, predicting to monitored Iocations and comparing the predicted and monitored noise Ievels. These predicted levels were used to determine the degree of structural noise attenuation required to meet New York City’s interior residential noise requirements of 45 dBA.

10:50

2NS6. The effecf of onset ratę on aireraft noise annoyance. Kenneth J. Plotkin, Kevin A. Bradley (Wyle Labs.. 2001 Jefferson Davis Hwy., Ste. 701, Arlington, VA 22202), and John A. Molino (Tech-U-Fit Corp., Alexandria, VA 22314)

Noise from military aireraft operating at high speeds and Iow alti-tude can exhibit high onset rates, which are thought to inerease the annoyance of these sounds. A set of listening experiments was under-taken to examine this effect and to evaluate the validity of an onset ratę adjustment currently used in the environmental assessment of this type of noise. A basie set of 12 stereo sound recordings was prepared, con-sisting of four types of military aireraft with various onset rates plus one civil aireraft. These aireraft flyby sounds were presented at four sound levels to subjccts in an indoor listening facility (nominał SEL of 95, 85, 75, and 65 dB) and at an outdoor facility (nominał SELof 115, 105, 95, and 85 dB). Indoor sounds were filtered according to a typical residential noise reduction curvc. Sounds were presented in random order, at random time intervals, and random approach from either in front of or behind the subjeets. Subjeets rated each sound on a seven-point annoyance scalę. Two companion experiments were aLso performed at the outdoor facility. These experiments used modified military aireraft sounds with particular onset rates from 5 to 100 dB/s and decay rates from 2 to 30 dB/s. Analysis of the results of these experiments examined the effeets of onset and decay rates, levcl, SEL, and duration. (Work sponsored by USAF AAMRL/BBE.]

11.-05

2NS7. An exploratory study of community noise levels in the city of Lima. Carlos R. Jimenez-Dianderas and Ivan F. Rivas-Tejeda (Garcilaso de la Vega 163, Salamanca de Monterrico, Lima 3, Peru)

Lima, the Capital city of Peru, a metro|>olis with morę than 6 million 121 st Meeting: Acoustical Society of America 1861