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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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    <item>
      <title>Advanced Electrical Signature Analysis of Aircraft Electrical Generators</title>
      <link>https://trid.trb.org/View/1430966</link>
      <description><![CDATA[The electrical and mechanical failures (such as bearing and winding failures) combine to cause premature failures of the generators, which become a flight safety issue forcing the crew to land as soon as practical. Currently, diagnostic / prognostic technologies are not implemented for aircraft generators where repairs are time consuming and its costs are high. This paper presents the development of feature extraction and diagnostic algorithms to ultimately 1) differentiate between these failure modes and normal aircraft operational modes; and 2) determine the degree of damage of a generator. Electrical signature analysis based features were developed to distinguish between healthy and degraded generators while taking into account their operating conditions. The diagnostic algorithms were developed to have a high fault / high-hour detection rate along with a low false alarm rate. The feature extraction and diagnostic algorithms were evaluated against P-3 generator data (phase voltages / currents) collected at various loads and operating line frequencies for healthy, low-hour and high-hour generators. The results show that the electrical signature analysis of the generator's phase voltage(s) can be used to detect and track its health.       ]]></description>
      <pubDate>Mon, 24 Apr 2017 18:22:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/1430966</guid>
    </item>
    <item>
      <title>Advanced Electrical Signature Analysis to Track the Health of Aircraft Electrical Generators</title>
      <link>https://trid.trb.org/View/1432761</link>
      <description><![CDATA[Electrical and mechanical failures (such as bearing, winding and rotating-diode failures) combine to cause premature failures of the generators, which become a flight safety issue forcing the crew to land as soon as practical. Currently, diagnostic / prognostic technologies are not implemented for aircraft generators where repairs are time-consuming and costly. This paper presents the development of feature extraction and diagnostic algorithms to 1) differentiate between these failure modes and normal aircraft operational modes; and 2) determine the degree of damage of a generator. Electrical signature analysis (ESA) based time-domain features were developed to distinguish between healthy and degraded generators while taking into account their operating conditions. Frequency-domain based ESA techniques are used to identify the degraded components within the generators. The diagnostic algorithms were developed to have a high fault / high-hour detection rate along with a low false alarm rate. The feature extraction and diagnostic algorithms were evaluated against P-3 generator data (phase voltages/currents, exciter current) collected at various loads and operating line frequencies for the following: 1) healthy, low-hour and high-hour generators; and 2) a generator undergoing endurance testing. The results show that the electrical signature analysis of the generator's phase voltages can be used to detect and track its health. Work is in progress to develop and validate diagnostic and prognostic algorithms for electrical generators attached to linear and nonlinear loads for various operating conditions.       ]]></description>
      <pubDate>Thu, 05 Jan 2017 16:25:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/1432761</guid>
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    <item>
      <title>DEVELOPMENT OF REAL-TIME MINE ROAD MAINTENANCE MANAGEMENT SYSTEM USING HAUL TRUCK AND ROAD VIBRATION SIGNATURE ANALYSIS</title>
      <link>https://trid.trb.org/View/645221</link>
      <description><![CDATA[The unpaved road network of a surface mine is extensive, comprising numerous roads of varying construction and material qualities with highly variable traffic volumes.  Existing haul road maintenance management systems (MMSs) work well for predictable traffic volumes, but for complex mine road networks, the MMS becomes onerous and results in suboptimal road maintenance strategies, with the attendant increase in total road-user costs and reduction in service.  A real-time MMS was thus sought to overcome the deficiencies of existing systems for mine roads.  Because most large mines operate trucks with onboard diagnostic data collation, linked through a centralized communication and Global Positioning System backbone, it was proposed that road condition could be monitored on a real-time basis through onboard vibration signature analysis.  A real-time mine haul road MMS was developed.  Mine road maintenance practices were reviewed.  The real-time system architecture was devised, and a field trial was conducted of onboard vibration signature assessment.  Trial results were evaluated in the light of road defect signature recognition, analysis, signature repeatability, and system limitations.  This approach is applicable to other situations, such as a network of district roads, subject to an analysis of economic feasibility.  The conclusion is reached that modern technology has the potential to apply maintenance as and where needed, with possible reductions in authority cost and an improvement in service provided to road users.]]></description>
      <pubDate>Fri, 09 May 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/645221</guid>
    </item>
    <item>
      <title>USE OF VEHICLE SIGNATURE ANALYSIS AND LEXICOGRAPHIC OPTIMIZATION FOR VEHICLE RE-IDENTIFICATION ON FREEWAYS</title>
      <link>https://trid.trb.org/View/503431</link>
      <description><![CDATA[This paper presents the vehicle reidentification problem formulated as a lexicographic optimization problem. Lexicographic optimization is a preemptive multi-objective formulation, and this lexicographic optimization formulation combines lexicographic goal programming, classification, and Bayesian analysis techniques.  The solution of the vehicle reidentification problem has the potential to yield reliable section measures such as travel times and densities, and enables the measurement of specific dynamic origin/destination demands. Implementation of this approach using conventional surveillance infrastructure permits the development of new algorithms for ATMIS (Advanced Transportation Management and Information Systems).  Freeway inductive loop data from SR-24 in Lafayette, California, demonstrates that robust results can be obtained under different traffic flow conditions.  The use of existing surveillance infrastructure coupled with this approach allows development of widespread applications in Intelligent Transportation Systems (ITS).]]></description>
      <pubDate>Fri, 03 Sep 1999 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/503431</guid>
    </item>
    <item>
      <title>PROBLEMS AND METHODS FOR CONTROLLING THE NOISE SIGNATURE OF A VESSEL</title>
      <link>https://trid.trb.org/View/433910</link>
      <description><![CDATA[The problem of detecting submarine or surface vessels is tackled using signature techniques, by which the vessel is identified according to its specific characteristics. Depending on the physical size considered, one can speak of noise, pressure, magnetic, radar or infrared signatures. In detecting a vessel from submarines, systems based on electromagnetic waves must be excluded and therefore only the first three of the alternatives may be considered. Another distinction may be made depending on the range of distances over which they operate and their identification capabilities. Acoustic detection by passive systems is feasible over considerable distances, even up to tens of kilometres, and in addition to determining the presence and position of the vessel it is also possible to ascertain several useful characteristics for identifying it, such as the type of propulsion, r.p.m., number of propeller blades and so on. Active acoustic systems also allow detection over large distances and give fairly accurate information concerning the size of the vessel. Magnetic and pressure detection systems operate over shorter distances and are mainly limited to detecting the presence of a vessel from the point of view of its components and the possible ways of controlling and reducing its detectability by passive noise sensors.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/433910</guid>
    </item>
    <item>
      <title>AN EXPERT SYSTEM FOR REAL-TIME NOISE AND VIBRATION ANALYSIS OF SHIPBOARD EQUIPMENT</title>
      <link>https://trid.trb.org/View/391379</link>
      <description><![CDATA[An expert system that allows real-time analysis of the noise and vibration signature of vibrating machinery is described. The system presented consists of an adaptive algorithm that varies the band width of analysis channels as a function of a signal complexity factor and a measure of the rapidity of local signal change. Overall program architecture is presented as well as detailed discussion of signature functional identification and statistical trend modules which are adaptable to a wide variety of input data base configurations. Execution of the program on a "super-mini" in FORTRAN code with direct graphics output and on 68000 series based firmware using ADA is discussed. Results are presented of program execution on Navy hydrophone and propulsion gas turbine data showing current signature and projections of trend to future times compared with failed condition signatures. Correlation results for such predictions are also discussed.]]></description>
      <pubDate>Thu, 21 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/391379</guid>
    </item>
    <item>
      <title>OPEN OCEAN TSUNAMI DETECTION AND WARNING SYSTEM</title>
      <link>https://trid.trb.org/View/395496</link>
      <description><![CDATA[To improve the reliability and accuracy of tsunami forecasts, a warning system based on high resolution bottom pressure measurements in mid-ocean is proposed and discussed. The critical question of tsunami detectability is considered, using available pertinent data on open-ocean tsunami signatures and background noises. It has been demonstrated that the reliable detection of a tsunami with an average amplitude as small as 0.7 cm is possible using appropriate signal processing. Tsunami directionality is considered as it affects the spatial location of monitoring stations. The simple model proposed predicts tsunami beamwidth as small as 16 degrees using realistic tsunami parameters.]]></description>
      <pubDate>Thu, 21 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/395496</guid>
    </item>
    <item>
      <title>CONDITION MONITORING OF MACHINERY USING MOTOR CURRENT SIGNATURE ANALYSIS</title>
      <link>https://trid.trb.org/View/403122</link>
      <description><![CDATA[This paper deals with the use of motor current signature analysis (MCSA) as a monitoring tool for motor-driven equipment. MCSA was developed to determine the effects of service wear on motor-operated valves used in nuclear power plant safety systems. Examples are given of MCSA technology application and the applicability of MCSA to a broader range of equipment monitoring is also discussed.]]></description>
      <pubDate>Thu, 21 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/403122</guid>
    </item>
    <item>
      <title>USE OF PRESSURE PULSATION MONITORING FOR RECIPROCATING COMPRESSION CONDITION MONITORING</title>
      <link>https://trid.trb.org/View/403131</link>
      <description><![CDATA[This paper describes an advanced warning system for maintenance and control of reciprocating compressors. The effect of common defects such as piston ring wear and leaking valves on pressure pulsation signatures was investigated and compared with healthy signatures and their harmonic components. It was shown that the pressure pulsation signatures may be used as an indication for condition monitoring of a reciprocating compressor.]]></description>
      <pubDate>Thu, 21 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/403131</guid>
    </item>
    <item>
      <title>MECHANICAL SIGNATURE ANALYSIS: FORMAL TOOLS AND COMMON SENSE</title>
      <link>https://trid.trb.org/View/407729</link>
      <description><![CDATA[Machinery diagnostic relies heavily on signature methods, and their choice affects all phases of the monitoring task. Availability, ease of use, and documented successes may be deceiving. As in all engineering tasks, common sense does not have to be delegated to a secondary place. A review of the diagnostic process is followed by case histories, to show that a systematic approach is not only viable but possible. The aim is to implement a successful monitoring system; theoretical understanding, skills with formal tools and, not least, common sense, will make this easier.]]></description>
      <pubDate>Thu, 21 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/407729</guid>
    </item>
    <item>
      <title>OIL PRESSURE SIGNATURES FOR ENGINE LUBRICATION SYSTEM MONITORING</title>
      <link>https://trid.trb.org/View/211285</link>
      <description><![CDATA[This paper describes an application of signature analysis techniques to oil pressure signals of internal combustion engines for monitoring the status of an engine lubrication system.  The dynamic characteristics of a lubrication flow network are presented.  The state of the lubrication system is reflected not only in the mean or D.C. component, but also in higher frequencies of the signal.  Experimental results are presented for both periodic and position locked components of the pulsatile signals.  The signal characteristics are altered if a defect is present in the engine.  Signal characteristics are affected due to perturbations introduced by the defect present downstream in the lubrication system.  The changes in oil pressure signals are sensitive to oil temperature and proximity of the defect to the monitoring point. Results are presented to indicate limitations of such analysis techniques for lubrication system fault detection.]]></description>
      <pubDate>Thu, 28 Feb 1985 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/211285</guid>
    </item>
    <item>
      <title>VIBRATION SIGNATURE ANALYSIS AS A PREVENTIVE MAINTENANCE TOOL ABOARD SHIP</title>
      <link>https://trid.trb.org/View/76286</link>
      <description><![CDATA[This paper describes vibration measurements of shipboard machines which are now being utilized in a program of preventive maintenance as a supplement to standard shipboard maintenance procedures.  While similar in many respects to vibration measurements used ashore, the shipboard program must take into account environmental vibrations that occasionally mask the vibration of shipboard machines. Illustrations are shown of these environmental vibrations that are caused primarily by propeller blade passing frequencies and random turbulence from the propeller and hull.  Implementation of a shipboard program using two portable instruments, a vibration meter and an analyzer/XY recorder, is briefly described.  The value of such a program results from its ability to detect machine deterioration in its earliest stages while there is sufficient time to correct problems before they reach the critical stage. Examples of vibration signatures indicating machinery defects are given.  Measurement techniques and procedures are also discussed which have been developed to pinpoint defects and separate environmental vibrations from those associated with the machines.]]></description>
      <pubDate>Tue, 31 Oct 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/76286</guid>
    </item>
    <item>
      <title>CONCORDE NOISE-INDUCED BUILDING VIBRATIONS, JOHN F. KENNEDY INTERNATIONAL AIRPORT</title>
      <link>https://trid.trb.org/View/75145</link>
      <description><![CDATA[The outdoor/indoor noise levels and associated vibration levels resulting from aircraft and nonaircraft events were recorded at eight homesites and a school. In addition, limited subjective tests were conducted to examine the human detection/annoyance thresholds for building vibration and rattle caused by aircraft noise. Presented herein are the majority of the window and wall vibration data recorded during Concorde and subsonic aircraft overflights.]]></description>
      <pubDate>Sat, 19 Aug 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/75145</guid>
    </item>
    <item>
      <title>SONIC SIGNATURE MONITOR FOR INTERNAL COMBUSTION ENGINES</title>
      <link>https://trid.trb.org/View/57364</link>
      <description><![CDATA[A piezoelectric sonic signature evaluation system has been developed to monitor scuffing, injection and combustion. The monitor consists of the transducer and a signal evaluation unit.  The signatures of normal and abnormal operation conditions may be predicted, and the appearance of new signals and the disappearance of normal signals are criteria for engine malfuncition.]]></description>
      <pubDate>Mon, 30 Jan 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/57364</guid>
    </item>
    <item>
      <title>ESTABLISHING THE FAILURE PATTERN BASE THROUGH SIGNATURE ANALYSIS</title>
      <link>https://trid.trb.org/View/328</link>
      <description><![CDATA[Examples of various sensing technqiues which may be useful in signature analysis are presented.  A discussion is included of some of primary failure modes of non-electronic components and how these might be monitored to determine the condition of a mechanical system.  Designer of mechanical systems must be aware of what likely failure modes may be. Knowledge of how precursors of these failure modes might be detected is also necessary.  Increased emphasis on reliability and maintainability requirements of todays mechanical systems is forcing all designers to become increasingly aware of the variety of scientific disciplines available to assist them in their tasks.]]></description>
      <pubDate>Sun, 25 Nov 1973 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/328</guid>
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