Java tutorial
/** * Copyright (c) 2011 Metropolitan Transportation Authority * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ package org.onebusaway.nyc.vehicle_tracking.impl.inference; import java.util.Set; import org.onebusaway.geospatial.model.CoordinatePoint; import org.onebusaway.geospatial.services.SphericalGeometryLibrary; import org.onebusaway.nyc.vehicle_tracking.impl.inference.ObservationCache.EObservationCacheKey; import org.onebusaway.nyc.vehicle_tracking.impl.inference.state.BlockState; import org.onebusaway.nyc.vehicle_tracking.impl.particlefilter.CDFMap; import org.onebusaway.nyc.vehicle_tracking.impl.particlefilter.DeviationModel; import org.onebusaway.nyc.vehicle_tracking.services.DestinationSignCodeService; import org.onebusaway.transit_data_federation.model.ProjectedPoint; import org.onebusaway.transit_data_federation.services.blocks.BlockInstance; import org.onebusaway.transit_data_federation.services.blocks.ScheduledBlockLocation; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; @Component class BlockStateSamplingStrategyImpl implements BlockStateSamplingStrategy { private static Logger _log = LoggerFactory.getLogger(BlockStateSamplingStrategyImpl.class); private DestinationSignCodeService _destinationSignCodeService; /** * We need some way of scoring nearby trips */ private DeviationModel _nearbyTripSigma = new DeviationModel(400.0); private DeviationModel _scheduleDeviationSigma = new DeviationModel(32 * 60); private BlockStateService _blockStateService; private BlocksFromObservationService _blocksFromObservationService; private ObservationCache _observationCache; /**** * Public Methods ****/ @Autowired public void setDestinationSignCodeService(DestinationSignCodeService destinationSignCodeService) { _destinationSignCodeService = destinationSignCodeService; } @Autowired public void setBlockStateService(BlockStateService blockStateService) { _blockStateService = blockStateService; } @Autowired public void setBlocksFromObservationService(BlocksFromObservationService blocksFromObservationService) { _blocksFromObservationService = blocksFromObservationService; } @Autowired public void setObservationCache(ObservationCache observationCache) { _observationCache = observationCache; } /** * * @param scheduleDeviationSigma time, in seconds */ public void setScheduleDeviationSigma(int scheduleDeviationSigma) { _scheduleDeviationSigma = new DeviationModel(scheduleDeviationSigma); } @Override public CDFMap<BlockState> cdfForJourneyAtStart(Observation observation) { CDFMap<BlockState> cdf = _observationCache.getValueForObservation(observation, EObservationCacheKey.JOURNEY_START_BLOCK_CDF); if (cdf == null) { Set<BlockInstance> potentialBlocks = _blocksFromObservationService .determinePotentialBlocksForObservation(observation); cdf = new CDFMap<BlockState>(); StringBuilder b = null; if (_log.isDebugEnabled()) { b = new StringBuilder(); b.append("potential blocks found: ").append(potentialBlocks.size()); } for (BlockInstance blockInstance : potentialBlocks) { // Start at the beginning of the block BlockState state = _blockStateService.getAsState(blockInstance, 0.0); double p = scoreJourneyStartState(state, observation); cdf.put(p, state); if (_log.isDebugEnabled()) { b.append("\n" + state.getBlockLocation().getDistanceAlongBlock() + "\t" + state.getBlockLocation().getScheduledTime() + "\t" + p + "\t" + blockInstance); } } if (_log.isDebugEnabled()) _log.debug(b.toString()); _observationCache.putValueForObservation(observation, EObservationCacheKey.JOURNEY_START_BLOCK_CDF, cdf); } return cdf; } @Override public CDFMap<BlockState> cdfForJourneyInProgress(Observation observation) { CDFMap<BlockState> cdf = _observationCache.getValueForObservation(observation, EObservationCacheKey.JOURNEY_IN_PROGRESS_BLOCK_CDF); if (cdf == null) { Set<BlockInstance> potentialBlocks = _blocksFromObservationService .determinePotentialBlocksForObservation(observation); cdf = new CDFMap<BlockState>(); StringBuilder b = null; if (_log.isDebugEnabled()) { b = new StringBuilder(); b.append("potential blocks found: " + potentialBlocks.size()); } for (BlockInstance blockInstance : potentialBlocks) { BlockState state = _blockStateService.getBestBlockLocation(observation, blockInstance, 0, Double.POSITIVE_INFINITY); double p = scoreState(state, observation); cdf.put(p, state); if (_log.isDebugEnabled()) { b.append("\n" + state.getBlockLocation().getDistanceAlongBlock() + "\t" + state.getBlockLocation().getScheduledTime() + "\t" + p + "\t" + blockInstance); } } if (_log.isDebugEnabled()) _log.debug(b.toString()); /** * Cache the result */ _observationCache.putValueForObservation(observation, EObservationCacheKey.JOURNEY_IN_PROGRESS_BLOCK_CDF, cdf); } return cdf; } /**** * Private Methods ****/ private double scoreJourneyStartState(BlockState state, Observation observation) { return scoreJourneyStartDestinationSignCode(state, observation); } private double scoreState(BlockState state, Observation observation) { ScheduledBlockLocation blockLocation = state.getBlockLocation(); CoordinatePoint p1 = blockLocation.getLocation(); ProjectedPoint p2 = observation.getPoint(); double d = SphericalGeometryLibrary.distance(p1.getLat(), p1.getLon(), p2.getLat(), p2.getLon()); double prob1 = _nearbyTripSigma.probability(d); BlockInstance blockInstance = state.getBlockInstance(); long serviceDate = blockInstance.getServiceDate(); int scheduledTime = blockLocation.getScheduledTime(); long time = serviceDate + scheduledTime * 1000; long recordTime = observation.getTime(); long timeDelta = Math.abs(time - recordTime) / 1000; double prob2 = _scheduleDeviationSigma.probability(timeDelta); return prob1 * prob2; } private double scoreJourneyStartDestinationSignCode(BlockState state, Observation observation) { String observedDsc = observation.getLastValidDestinationSignCode(); boolean observedOutOfService = _destinationSignCodeService.isOutOfServiceDestinationSignCode(observedDsc); // If we have an out-of-service DSC, then we favor it equally if (observedOutOfService) { return 0.5; } else { // Favor blocks that match the correct DSC String dsc = state.getDestinationSignCode(); if (observedDsc.equals(dsc)) return 0.95; else return 0.25; } } }