Discrete Elastic Inner Vector Spaces with Application in Time Series and Sequence Mining

This paper proposes a framework dedicated to the construction of what we call discrete elastic inner product allowing one to embed sets of non-uniformly sampled multivariate time series or sequences of varying lengths into inner product space structures. This framework is based on a recursive definition that covers the case of multiple embedded time elastic dimensions. We prove that such inner products exist in our general framework and show how a simple instance of this inner product class operates on some prospective applications, while generalizing the Euclidean inner product. Classification experimentations on time series and symbolic sequences datasets demonstrate the benefits that we can expect by embedding time series or sequences into elastic inner spaces rather than into classical Euclidean spaces. These experiments show good accuracy when compared to the euclidean distance or even dynamic programming algorithms while maintaining a linear algorithmic complexity at exploitation stage, although a quadratic indexing phase beforehand is required.Comment: arXiv admin note: substantial text overlap with arXiv:1101.431

On-road testing with Portable Emissions Measurement Systems (PEMS) - Guidance note for light-duty vehicles

This guidance note describes the best practice for the preparation, the execution, and the follow-up of emissions tests that are conducted with PEMS on board of light-duty vehicles (LDV) equipped with conventional combustion engines (gasoline, diesel, CNG, LPG), in particular for testing vehicles according to the RDE legislative requirements laid down in Regulations (EU) 2017/1151, 2016/427, 2016/646, 2017/1154, and the last "RDE4" package approved at TCMV on May 3rd 2018 (collectively referred to in this document as the EU-RDE LDV regulations).JRC.C.4-Sustainable Transpor

Heavy-Duty Engines-Conformity Testing based on PEMS - Lessons Learned from the European Pilot Program

The European emissions legislation requires to check the conformity of heavy-duty engines with the applicable emissions certification standards during the normal life of those engines: these are the “In Service Conformity” (ISC) requirements. It was considered impractical and expensive to adopt an in-service conformity (ISC) checking scheme for heavy-duty vehicles, which require removal of engines from vehicles to test pollutant emissions against legislative limits. Therefore, it has been proposed to develop a protocol for in-service conformity checking of heavy-duty vehicles based on the use of Portable Emission Measurement Systems (PEMS). The European Commission through DG ENTR in co-operation with DG JRC launched in January 2004 a co-operative research programme to study the feasibility of PEMS in view of their application in Europe for In-Service Conformity of heavy-duty engines. The technical and experimental activities were started in August 2004 to study the feasibility of PEMS systems and to study their potential application for on-road measurements on heavy-duty vehicles.The main objectives of the above project had been defined as follows: -To assess and validate the application and performance of portable instrumentation relative to each other, and in comparison with alternative options for ISC testing; -To define a test protocol for the use of portable instrumentation within the ISC of heavy-duty vehicles; -To assess on-road data evaluation methods such as the US ‘Not To Exceed’ (NTE) approach and possibly to develop a simplified ones; -To address the need of the European industry, authorities and test houses to go through a learning process with on-vehicle emissions testing. The main objective of the present document is to report on: a. The evaluation of the test protocol, i.e. to judge whether the mandatory data and its quality were appropriate for the final evaluation (S b. The analysis conducted to evaluate the potential of the different data evaluation (Pass/Fail) methods for ISC and in particular their ability to use on-road PEMS emissions data. The candidate methods were categorized into two families: -The "control-area / data reduction methods" (Chapter 4) that use only a part of the data, depending whether the operation points considered are part of a control area and belong to a sequence of consecutive points within this control area. The US-NTE (Not To Exceed) method - already established as an official tool in the United States - falls into this category but variations of the methods could be envisaged (with another control area for instance). -The "averaging window methods" (Chapter 4.3) that use all the operation data. The main objective of task b. was to answer the following question: “Once the data has been collected correctly, what is the most appropriate method to analyze the test data measured with PEMS and to judge whether the engine is in conformity with the applicable emissions limits?”JRC.F.9-Sustainable Transport (Ispra

Spiral Walk on Triangular Meshes : Adaptive Replication in Data P2P Networks

We introduce a decentralized replication strategy for peer-to-peer file exchange based on exhaustive exploration of the neighborhood of any node in the network. The replication scheme lets the replicas evenly populate the network mesh, while regulating the total number of replicas at the same time. This is achieved by self adaptation to entering or leaving of nodes. Exhaustive exploration is achieved by a spiral walk algorithm that generates a number of messages linearly proportional to the number of visited nodes. It requires a dedicated topology (a triangular mesh on a closed surface). We introduce protocols for node connection and departure that maintain the triangular mesh at low computational and bandwidth cost. Search efficiency is increased using a mechanism based on dynamically allocated super peers. We conclude with a discussion on experimental validation results

A complementary emissions test for light-duty vehicles: Assessing the technical feasibility of candidate procedures

Light-duty diesel vehicles emit on the road substantially more nitrogen oxides than permitted by regulatory emissions standards. The European Commission addresses this problem by developing a complementary emissions test procedure for the type approval and in-service conformity testing of these vehicles. To facilitate the technical development, the European Commission established in January 2011 the Real-Driving Emissions - Light-Duty Vehicles (RDE-LDV) working group that is open to all stakeholders. This report presents the results of the technical assessment that was carried out by the RDE-LDV working group for two candidate procedures: (i) emissions testing with random driving cycles in the laboratory and (ii) on-road emissions testing with Portable Emissions Measurement Systems (PEMS). Both procedures are technically feasible. However, PEMS on-road testing appears to be more effective than random-cycle testing in limiting the pollutant emissions of light-duty vehicles because it (i) allows a wider range of driving conditions to be covered and (ii) might more effectively prevent the detection of emissions tests and the use of defeat strategies. Nonetheless, PEMS on-road testing faces practical challenges, including open safety issues, the currently limited availability of PEMS equipment, and potential climatic, geographical, and seasonal constraints for the execution of emissions tests. Random-cycle testing presents advantages over PEMS on-road testing in that already established laboratory equipment and know-how to be used. The present assessment is subject to uncertainty because the implementation and running costs as well as the overall effectiveness of the two candidate procedures depend on the definition of concrete boundary conditions (e.g., permitted test temperatures, severity of driving patterns). These definitions are not yet agreed. Accounting for the resulting uncertainty, it has been decided that the JRC will develop a PEMS-based test procedure. Vehicle manufacturers are given the opportunity to develop a random cycle-based test procedure. A decision will be made regarding the implementation for type approval and in-service conformity testing based on a comparison of the two fully developed test procedures by the end of 2013.JRC.F.8-Sustainable Transpor

Technical, Operational and Logistical Parameters Influencing Emissions of Heavy Duty Vehicles

The focus of this study is the analysis of collected data of real world emission measurements of a heavy duty vehicle using a Portable Emission Measurement System (PEMS) along a large portion of the extended Trans-European Transport CORRIDOR V. The aim of the analysis is to assess heavy duty vehicle emission in different real-world transport conditions and their correlations i.e. transport factors influencing emissions.JRC.H.4-Transport and air qualit

Real Driving Emissions: 2017 Assessment of PEMS measurement uncertainty

Regulation 2016/427 introduced on-road testing with Portable Emissions Measurement Systems (PEMS) to complement the laboratory Type I test for the type approval of light-duty vehicles in the European Union. A NOx conformity factor of 1.5 will apply from January 2020/2021. This conformity factor includes a margin of 0.5 to account for the additional measurement uncertainty of PEMS relative to standard laboratory equipment. Said margin (and also the PN margin, initially set at 0.5 by Regulation (EU) 2017/1154 (RDE3), has to be reviewed annually (Recital 10 of Regulation 2016/646). This report summarizes the first review of the NOx margin and lays out the framework for future margin reviews. Since the PN margin was first set in 2017, it was not included in the 2017 review exercise. Based on experimental data received by the stakeholders, technical improvements of PEMS and assumptions of possible zero drift during the tests, a NOx margin of 0.24 to 0.43 was calculated.JRC.C.4-Sustainable Transpor

Real Driving Emissions Regulation: European Methodology to fine tune the EU Real Driving Emissions data evaluation method

This European Commission – JRC Technical Report presents a detailed analysis of a dataset made up of 11 passenger cars which have been emission tested during on-road trips for a total of 79 tests. The data set was mostly produced at JRC; except for 3 vehicles. In the framework of the United Nations Economic Commission for Europe (UNECE), the JRC supports DG-GROW (Internal Market, Industry, Entrepreneurship and SMEs) in order to develop an UNECE Regulation and a Global Technical Regulation (GTR) which should include real driving emissions (RDE) testing provisions for several extra-EU countries starting from Japan and South Korea and possibly including India, China, Canada and United States. As a preliminary input to the Global Real Driving informal working group at UNECE, this Report describes the latest EU-RDE procedure (RDE-4, Regulation EU 2018/1832) with focus on the response given by the RDE data analysis tool (EMROAD version 6.03, designed and maintained by JRC). The data set includes RDE tests expressily designed to cover extended boundary conditions (e.g. for temperature and altitude) and to challenge the requirements on trip dynamics which were laid down in the legislation to define the normal condition of vehicle use. EMROAD succesfully produced, and evaluated against requirements, the entire set of parameters defining the trip validity: trip duration, distance and distance shares, vehicle speed and speed shares, trip dynamics, ambient conditions, elevation gain, trip severity with respect to the WLTP driving cycle (based on CO2), emissions of pollutants and their correction for ambient boundary conditions and for excess of severity. The tool was also used to fine tune the tolerances around the CO2 characteristic curve, an useful feature when assessing the degree of test severity which is considered acceptable by the legislator in a specific country. In addition, EMROAD incorporates the previous RDE-3 package (Regulation EU 2017/1151) so that a comparison between the old and most recent provisions can be done. For instance, it was found that the data set was affected by the different methods used in RDE-3 and RDE-4 to build the moving averaging windows for the evaluation of overall trip dynamics: more RDE tests are valid with the latest RDE-4 method than with the older RDE-3.JRC.C.4-Sustainable Transpor