Search results for "MAS"

Hits ?▲	Authors	Title	Venue	Year	Link	Author keywords
30	Manuel Kolp, Paolo Giorgini, John Mylopoulos	A Goal-Based Organizational Perspective on Multi-agent Architectures.	ATAL	2001	DBLP DOI BibTeX RDF
30	Kiriakos Kiriakidis, Diana F. Gordon	Adaptive Supervisory Control of Multi-agent Systems.	FAABS	2000	DBLP DOI BibTeX RDF
30	Omer F. Rana, Thomas Wagner, Michael S. Greenberg, Martin K. Purvis	Infrastructure Issues and Themes for Scalable Multi-Agent Systems.	Agents Workshop on Infrastructure for Multi-Agent Systems	2000	DBLP DOI BibTeX RDF
30	Onn Shehory	Software Architecture Attributes of Multi-agent Systems.	AOSE	2000	DBLP DOI BibTeX RDF
30	Munindar P. Singh	Conceptual Modeling for Multiagent Systems: Applying Interaction-Oriented Programming.	Conceptual Modeling	1997	DBLP DOI BibTeX RDF
30	Enyo José Tavares Gonçalves, Mariela Inés Cortés, Gustavo A. L. de Campos, Gilzamir F. Gomes, Viviane Torres da Silva	Towards the modeling reactive and proactive agents by using MAS-ML.	SAC	2010	DBLP DOI BibTeX RDF	multiagent systems, modelling language
30	Vincent Wiegel, Jan van den Berg	Combining Moral Theory, Modal Logic and Mas to Create Well-Behaving Artificial Agents.	Int. J. Soc. Robotics	2009	DBLP DOI BibTeX RDF	Deontic constraints, Trust, Software agents, Modal logic, BDI, Morality
30	Yan Cao, Jiang Du 0004, Yu Bai 0006, Lina Yang, Yanli Yang	Multi-layer Intelligent Encapsulation of Manufacturing Resources for MAS-based Distributed Manufacturing System.	WKDD	2009	DBLP DOI BibTeX RDF
30	Stella Heras, Vicente Julián, Vicente J. Botti	CBR Contributions to Argumentation in MAS.	Innovations in Hybrid Intelligent Systems	2008	DBLP DOI BibTeX RDF
30	Emilia Garcia, Adriana Giret, Vicente J. Botti	On the evaluation of MAS development tools.	IFIP AI	2008	DBLP DOI BibTeX RDF
30	Konstantin A. Aksyonov, Eugene A. Bykov, Elena F. Smoliy, Alexey A. Khrenov	Industrial enterprises business processes simulation with BPsim.MAS.	WSC	2008	DBLP DOI BibTeX RDF
30	Jiafang Wang, Zhiyong Feng 0002, Chao Xu 0003, Hui Wang, Qian Yang	A Control-Theoretic and Game-Theoretic Approach to Information Asymmetry in MAS.	IAT	2008	DBLP DOI BibTeX RDF
30	Jorge J. Gómez-Sanz, Juan A. Botía Blaya, Emilio Serrano, Juan Pavón	Testing and Debugging of MAS Interactions with INGENIAS.	AOSE	2008	DBLP DOI BibTeX RDF
30	Massimo Cossentino, Salvatore Gaglio, Stéphane Galland, Nicolas Gaud, Vincent Hilaire, Abderrafiaa Koukam, Valeria Seidita	A MAS Metamodel-Driven Approach to Process Fragments Selection.	AOSE	2008	DBLP DOI BibTeX RDF
30	António J. M. Castro, Eugénio C. Oliveira	Using Specialized Agents in a Distributed MAS to Solve Airline Operations Problems: A Case Study.	IAT	2007	DBLP DOI BibTeX RDF
30	Paola Salle, Danièle Hérin, Frédéric Duvert, Stefano A. Cerri	Dynamic Workflow in Grid-MAS Integration Context.	SYNASC	2007	DBLP DOI BibTeX RDF
30	Alessandro Ricci, Mirko Viroli, Andrea Omicini	Give agents their artifacts: the A&A approach for engineering working environments in MAS.	AAMAS	2007	DBLP DOI BibTeX RDF	artifact theory, artifact-based environments, environment design, multiagent system infrastructures, multiagent system languages, programming multiagent systems
30	Alessandro Ricci, Mirko Viroli, Andrea Omicini	CArtA gO : A Framework for Prototyping Artifact-Based Environments in MAS.	E4MAS	2006	DBLP DOI BibTeX RDF
30	Luca Gardelli, Mirko Viroli, Matteo Casadei, Andrea Omicini	Designing Self-organising MAS Environments: The Collective Sort Case.	E4MAS	2006	DBLP DOI BibTeX RDF
30	Emmanuelle Grislin-Le Strugeon, Abdouroihamane Anli, Emmanuel Adam	A Methodology to Bring MAS to Information Systems.	AOIS	2006	DBLP DOI BibTeX RDF
30	Hongbing Chen, Qun Yang, Manwu Xu	A Calculus for MAS Interaction Protocol.	PRIMA	2006	DBLP DOI BibTeX RDF	Dialogue protocol, Multi-agent, Interaction protocol, ?-Calculus
30	Weihua Yi, C. H. Zhang, Z. Liu, Xueguang Chen	Resource Coordination on MAS Multi-plans Context.	CEEMAS	2005	DBLP DOI BibTeX RDF
30	Quynh-Nhu Numi Tran, Brian Henderson-Sellers, John K. Debenham, Cesar Gonzalez-Perez	Conceptual Modelling within the MAS-CommonKADS Plus OPEN Method Engineering Approach.	ICITA (1)	2005	DBLP DOI BibTeX RDF
30	Andrea Omicini, Alessandro Ricci, Mirko Viroli	Coordination Artifacts as First-Class Abstractions for MAS Engineering: State of the Research.	SELMAS (LNCS)	2005	DBLP DOI BibTeX RDF
30	Les Gasser, Kelvin Kakugawa, Brant W. Chee, Marc Esteva	Smooth Scaling Ahead: Progressive MAS Simulation from Single PCs to Grids.	MABS	2004	DBLP DOI BibTeX RDF
30	Jian Li, Yuan-Da Cao	Bayesian Learning in Bilateral Multi-Issue Negotiation and Its Application in MAS-Based Electronic Commerc.	IAT	2004	DBLP DOI BibTeX RDF
30	XinJun Mao, Ji Wang 0001, Eric S. K. Yu	A Framework to Specify and Evaluate Coordination in MAS with Logic.	IAT	2004	DBLP DOI BibTeX RDF
30	Juan A. Botía, Juan Manuel Hernansaez, Antonio Fernandez Gómez-Skarmeta	Towards an Approach for Debugging MAS Through the Analysis of ACL Messages.	MATES	2004	DBLP DOI BibTeX RDF
30	Viviane Torres da Silva, Carlos José Pereira de Lucena	MAS-ML: a multi-agent system modeling language.	OOPSLA Companion	2003	DBLP DOI BibTeX RDF	multi-agent system, modeling language, conceptual framework
30	Viviane Torres da Silva, Ricardo Choren, Carlos José Pereira de Lucena	Using the MAS-ML to Model a Multi-agent System.	SELMAS	2003	DBLP DOI BibTeX RDF
30	Yan Qi 0001, Xin Wang, Wei Yan, XinJun Mao, Zhi-Chang Qi	A Formal Specification and Method for MAS as a Distributed System.	APPT	2003	DBLP DOI BibTeX RDF
30	David Hales, Bruce Edmonds	Evolving social rationality for MAS using "tags".	AAMAS	2003	DBLP DOI BibTeX RDF	cultural markers, evolution of groups, cooperation, tags, altruism, social cues
30	Mihaela Ulieru	The Holonic Enterprise: Modeling Holarchies as MAS to Enable Global Collaboration.	DEXA Workshops	2002	DBLP DOI BibTeX RDF	Holonic Enterprise, Web-Centric Enterprise, Co-opetition, Fuzzy-Evolutionary Approach, Holonic Clustering, Multi-Agent Systems, Virtual Enterprise
30	Alessandro Ricci, Andrea Omicini, Enrico Denti	Activity Theory as a Framework for MAS Coordination.	ESAW	2002	DBLP DOI BibTeX RDF
30	Bruce Edmonds	How Formal Logic Can Fail to Be Useful for Modelling or Designing MAS.	RASTA	2002	DBLP DOI BibTeX RDF
30	Jomi Fred Hübner, Jaime Simão Sichman, Olivier Boissier	MOISE+: towards a structural, functional, and deontic model for MAS organization.	AAMAS	2002	DBLP DOI BibTeX RDF	organization of multi-agent system
30	Stefano Mariani 0001, Andrea Omicini	Multi-paradigm Coordination for MAS: Integrating Heterogeneous Coordination Approaches in MAS Technologies.	WOA	2016	DBLP BibTeX RDF
30	Emeline Therias, Jon Bird, Paul Marshall	Más Tecnologia, Más Cambio?: Investigating an Educational Technology Project in Rural Peru.	CHI	2015	DBLP DOI BibTeX RDF
30	C. Theede	Das IBM System /32 und MAS - Computer und Programme nach Maß.	Elektron. Rechenanlagen	1976	DBLP DOI BibTeX RDF
25	Simon Lynch, Keerthi Rajendran	Providing Integrated Development Environments for Multi-Agent Systems.	MATES	2008	DBLP DOI BibTeX RDF	MAS, software architectures, debugging, deployment, IDE
25	Wanli Ma, Dat Tran 0001, Dharmendra Sharma 0001, Abhishek Mathur	Using Windows Printer Drivers for Solaris Applications - An Application of Multiagent System.	KES (3)	2006	DBLP DOI BibTeX RDF	printer drivers, MAS, operating systems, Multiagent
25	Dharmendra Sharma 0001, Wanli Ma, Dat Tran 0001, Mary Anderson	A Novel Approach to Programming: Agent Based Software Engineering.	KES (3)	2006	DBLP DOI BibTeX RDF	ABSE, Software Engineering, MAS, Multiagent Systems, Agent Based Software Engineering
25	Amina Tariq, Amna Basharat, Hafiz Farooq Ahmad, Hiroki Suguri, Arshad Ali	A Hybrid Agent Architecture for Modeling Autonomous Agents in SAGE.	IDEAL	2005	DBLP DOI BibTeX RDF	Hybrid Agent, MAS, Intelligent Agent, Autonomous agents, Agent Architecture
25	Weidong Fang, Ming Xi Tang, John H. Frazer	Supporting Collaborative Product Design in an Agent Based Environment.	IEA/AIE	2003	DBLP DOI BibTeX RDF	MAS, AI, Autonomous Agents, Collaborative Design, DCOM
24	Matteo Casadei, Andrea Omicini	Situated tuple centres in ReSpecT.	SAC	2009	DBLP DOI BibTeX RDF	A&A, MAS environment, tuple centres, artifacts, ReSpecT, situatedness
24	Ambra Molesini, Enrico Denti, Elena Nardini 0001, Andrea Omicini	Situated process engineering for integrating processes from methodologies to infrastructures.	SAC	2009	DBLP DOI BibTeX RDF	MAS infrastructures, TuCSoN, multi-agent systems, methodologies, methodology, software process, infrastructure, software development processes, situational method engineering, SPEM, SODA, AOSE
24	Ruixue Fu, Chaofeng Xu, Ming Song, Zhanhong Xin	Research on the Organizational Decision Support System for Small & Medium-Size Enterprise Based on Agent.	ISIP	2008	DBLP DOI BibTeX RDF	Organizational Decision Support Systems (ODSS), Multi-Agent System (MAS), Intelligent agents
24	Iván García-Magariño, Alma Gómez-Rodríguez, Jorge J. Gómez-Sanz, Juan Carlos González Moreno	INGENIAS-SCRUM Development Process for Multi-Agent Development.	DCAI	2008	DBLP DOI BibTeX RDF	INGENIAS, Multiagent Systems(MAS), development process, SCRUM, AOSE
24	Olivier Boissier, Jomi Fred Hübner, Jaime Simão Sichman	Organization Oriented Programming: From Closed to Open Organizations.	ESAW	2006	DBLP DOI BibTeX RDF	MAS organizations, Multi-agent Systems, Open systems
24	Sebastian Rodriguez, Vincent Hilaire, Abder Koukam	Holonic Modeling of Environments for Situated Multi-agent Systems.	E4MAS	2005	DBLP DOI BibTeX RDF	Holonic modeling, environment of MAS, simulation
24	Glenn T. Jayaputera, Seng Wai Loke, Arkady B. Zaslavsky	Just in time mobile agent generation and management.	AAMAS	2005	DBLP DOI BibTeX RDF	TDG, dynamic MAS, ehermes, mission, just in time, on demand
24	Martin K. Purvis, Noel Garside, Stephen Cranefield, Mariusz Nowostawski, Marcos de Oliveira 0001	Multi-agent System Technology for P2P Applications on Small Portable Devices.	AP2PC	2004	DBLP DOI BibTeX RDF	MAS technology, P2P, JXTA, portable devices
24	Alvaro E. Arenas, Gareth Barrera-Sanabria	Modelling Intelligent Agents for Organisational Memories.	KES	2003	DBLP DOI BibTeX RDF	MAS-CommonKADS, Knowledge Management, Agent-Oriented Software Engineering, Organisational Memory
24	Carles Sierra, Jordi Sabater, Jaume Agustí-Cullell, Pere Garcia	Integrating evolutionary computing and the SADDE methodology.	AAMAS	2003	DBLP DOI BibTeX RDF	MAS specification methodology, evolutionary computing
24	David Servat, Alexis Drogoul	Combining amorphous computing and reactive agent-based systems: a paradigm for pervasive intelligence?.	AAMAS	2002	DBLP DOI BibTeX RDF	reactive MAS, pervasive computing, self-organization
24	Ascensión Gallardo-Antolín, Ángel Navia-Vázquez, Harold Y. Molina-Bulla, A. B. Rodríguez-González, Francisco J. Valverde-Albacete, Jesús Cid-Sueiro, Aníbal R. Figueiras-Vidal, T. Koutris, C. Xirouhaki, Manolis Koubarakis	I-Gaia: an information processing layer for the DIET platform.	AAMAS	2002	DBLP DOI BibTeX RDF	coordinating multiple agents and multiple activities, layered systems, task validation, information retrieval, multi-agent systems (MAS), agent based software engineering, information routing, agent societies
23	Christian Hahn 0001, Cristián Madrigal-Mora, Klaus Fischer 0001	A platform-independent metamodel for multiagent systems.	Auton. Agents Multi Agent Syst.	2009	DBLP DOI BibTeX RDF	JACK, PIM4AGENTS, Model driven architecture, Metamodelling, PIM, Agent oriented software engineering, JADE, Agent modelling, BDI, Agent oriented, PSM
23	Jordi Campos Miralles, Maite López-Sánchez, Marc Esteva	Multi-agent system adaptation in a peer-to-peer scenario.	SAC	2009	DBLP DOI BibTeX RDF	coordination, multiagent systems, P2P, assistance
23	Yong Hee Kim, Seungwok Han, Chang Hun Lyu, Hee Yong Youn	An Efficient Dynamic Load Balancing Scheme for Multi-agent System Reflecting Agent Workload.	CSE (1)	2009	DBLP DOI BibTeX RDF
23	Sergey Babenyshev, Vladimir V. Rybakov	Describing Evolutions of Multi-Agent Systems.	KES (1)	2009	DBLP DOI BibTeX RDF	multi-agent systems, satisfiability, decision algorithms, Kripke semantics, multi-modal logics
23	Jonathan Ezekiel, Alessio Lomuscio	Combining fault injection and model checking to verify fault tolerance in multi-agent systems.	AAMAS (1)	2009	DBLP BibTeX RDF	fault tolerance, model checking, fault injection, epistemic logic
23	Vincent Hilaire, Abder Koukam, Sebastian Rodriguez	An adaptative agent architecture for holonic multi-agent systems.	ACM Trans. Auton. Adapt. Syst.	2008	DBLP DOI BibTeX RDF	Agents, immune systems, holonic systems
23	Maricela Bravo, José Velázquez	Discovering Pragmatic Similarity Relations between Agent Interaction Protocols.	OTM Workshops	2008	DBLP DOI BibTeX RDF	Pragmatic similarity, multi-agent systems, interaction protocols
23	Ulrich Münz, Antonis Papachristodoulou, Frank Allgöwer	Delay-dependent rendezvous and flocking of large scale multi-agent systems with communication delays.	CDC	2008	DBLP DOI BibTeX RDF
23	Norman Salazar, Juan A. Rodríguez-Aguilar, Josep Lluís Arcos	Infection-based self-configuration in agent societies.	GECCO (Companion)	2008	DBLP DOI BibTeX RDF	distributed evolutionary algorithm, infection-based algorithm, norms' evolution
23	José Júlio Alferes, Alfredo Gabaldon, João Leite 0001	Evolving Logic Programming Based Agents with Temporal Operators.	IAT	2008	DBLP DOI BibTeX RDF
23	Jose M. Such, Juan M. Alberola, Ana García-Fornes, Agustín Espinosa, Vicente J. Botti	Kerberos-Based Secure Multiagent Platform.	ProMAS	2008	DBLP DOI BibTeX RDF
23	Francesco Moscato 0001, Salvatore Venticinque, Rocco Aversa, Beniamino Di Martino	Formal Modeling and Verification of Real-Time Multi-Agent Systems: The REMM Framework.	IDC	2008	DBLP DOI BibTeX RDF
23	Dianxun Shuai, Qing Shuai	A Solitary Wave Approach to Parallel Optimization for Multi-agent Systems and Computer Networks.	FSKD (5)	2008	DBLP DOI BibTeX RDF
23	Aristides Mpitziopoulos, Charalampos Konstantopoulos, Damianos Gavalas, Grammati E. Pantziou	Hazard monitoring for visually impaired people enabled by wireless sensor networking technology.	PETRA	2008	DBLP DOI BibTeX RDF	hazard monitoring, itinerary design, wireless sensor networks, mobile agents, healthcare, assistive environments, itineraries
23	Julián J. Valencia-Jiménez, Antonio Fernández-Caballero 0001	Holonic Multi-agent System Model for Fuzzy Automatic Speech / Speaker Recognition.	KES-AMSTA	2008	DBLP DOI BibTeX RDF	Holony, Multi-agent systems, Speech recognition, Fuzziness, Speaker recognition
23	Josh Dehlinger, Robyn R. Lutz	Supporting requirements reuse in multi-agent system product line design and evolution.	ICSM	2008	DBLP DOI BibTeX RDF
23	Rafal Leszczyna	Anonymity Architecture for Mobile Agent Systems.	HoloMAS	2007	DBLP DOI BibTeX RDF
23	Tarek Jarraya, Zahia Guessoum	Towards a Model Driven Process for Multi-Agent System.	CEEMAS	2007	DBLP DOI BibTeX RDF
23	Alberto Fernández 0002, Sascha Ossowski	Semantic Service Composition in Service-Oriented Multiagent Systems: A Filtering Approach.	SOCASE	2007	DBLP DOI BibTeX RDF
23	Laëtitia Matignon, Guillaume J. Laurent, Nadine Le Fort-Piat	Hysteretic q-learning : an algorithm for decentralized reinforcement learning in cooperative multi-agent teams.	IROS	2007	DBLP DOI BibTeX RDF
23	Peter Warren, Deanne M. Taylor, Paolo G. V. Martini, Jennifer Jackson, Jadwiga R. Bienkowska	PANP - a New Method of Gene Detection on Oligonucleotide Expression Arrays.	BIBE	2007	DBLP DOI BibTeX RDF
23	Quang Huy Nguyen 0001, Yew-Soon Ong, Natalio Krasnogor	A study on the design issues of Memetic Algorithm.	IEEE Congress on Evolutionary Computation	2007	DBLP DOI BibTeX RDF
23	Thomas W. Lucas, Susan M. Sanchez, Felix Martinez, Lisa R. Sickinger, Jonathan W. Roginski	Defense and homeland security applications of multi-agent simulations.	WSC	2007	DBLP DOI BibTeX RDF
23	Carla T. L. L. Silva, João Araújo 0001, Ana Moreira 0001, Jaelson Castro	Designing Social Patterns Using Advanced Separation of Concerns.	CAiSE	2007	DBLP DOI BibTeX RDF
23	Sylvain Rougemaille, Frédéric Migeon, Christine Maurel, Marie-Pierre Gleizes	Model Driven Engineering for Designing Adaptive Multi-Agents Systems.	ESAW	2007	DBLP DOI BibTeX RDF
23	Simon Lynch, Keerthi Rajendran	Breaking into industry: tool support for multiagent systems.	AAMAS	2007	DBLP DOI BibTeX RDF	debugging, maintenance, agent oriented software engineering, development environments
23	Alberto Fernández 0002, Sascha Ossowski	Filters for semantic service composition in service-oriented multiagent systems.	AAMAS	2007	DBLP DOI BibTeX RDF	multiagent systems, service composition, semantic web services
23	Toru Eguchi, Kotaro Hirasawa, Jinglu Hu, Nathan Ota	A study of evolutionary multiagent models based on symbiosis.	IEEE Trans. Syst. Man Cybern. Part B	2006	DBLP DOI BibTeX RDF
23	Jorge J. Gómez-Sanz, Juan Pavón	Defining coordination in multi-agent systems within an agent oriented software engineering methodology.	SAC	2006	DBLP DOI BibTeX RDF	coordination modeling, agent interaction, agent coordination
23	Nazaraf Shah, Kuo-Ming Chao, Nick Godwin, Anne E. James, Chun-Lung Huang	A Sentinel Based Exception Diagnosis in Market Based Multi-Agent Systems.	DEECS	2006	DBLP DOI BibTeX RDF
23	Michel Barnad Geszychter, Beatriz Wilges, Silvia M. Nassar, Fernando Gauthier	A Model of a Multi-Agent Web System for Integration in Expert Systems.	CIMCA/IAWTIC	2006	DBLP DOI BibTeX RDF
23	Frédéric Duvert, Clément Jonquet, Pascal Dugenie, Stefano A. Cerri	Agent-Grid Integration Ontology.	OTM Workshops (1)	2006	DBLP DOI BibTeX RDF
23	Toshiharu Sugawara, Kensuke Fukuda, Toshio Hirotsu, Shin-ya Sato, Satoshi Kurihara	Adaptive Agent Selection in Large-Scale Multi-Agent Systems.	PRICAI	2006	DBLP DOI BibTeX RDF
23	Julián J. Valencia-Jiménez, Antonio Fernández-Caballero 0001	Holonic Multi-agent Systems to Integrate Independent Multi-sensor Platforms in Complex Surveillance.	AVSS	2006	DBLP DOI BibTeX RDF
23	Richard Hill, Simon Polovina, Dharmendra Shadija	Transaction Agent Modelling: From Experts to Concepts to Multi-Agent Systems.	ICCS	2006	DBLP DOI BibTeX RDF
23	Li-ming Wang, Ya-chong Li	A Systematic Methodology for Adaptive Systems in Open Environments.	PRIMA	2006	DBLP DOI BibTeX RDF	Organization Rule, Role Space, Adaptive Systems, Open Environments
23	Youmin Ke, Shanli Hu	A Concurrent Agent Model Based on Twin-Subset Semantic.	PRIMA	2006	DBLP DOI BibTeX RDF
23	Frodi Hammer, Alireza Derakhshan, Yves Demazeau, Henrik Hautop Lund	A Multi-Agent Approach to Social Human Behaviour in Children's Play.	IAT	2006	DBLP DOI BibTeX RDF
23	Toshiharu Sugawara, Kensuke Fukuda, Toshio Hirotsu, Shin-ya Sato, Satoshi Kurihara	Multi-Agent Systems Performance by Adaptive/Non-Adaptive Agent Selection.	IAT	2006	DBLP DOI BibTeX RDF
23	Predrag T. Tosic	On Modeling and Analyzing Sparsely Networked Large-Scale Multi-agent Systems with Cellular and Graph Automata.	International Conference on Computational Science (3)	2006	DBLP DOI BibTeX RDF
23	Satoshi Kataoka, Fuyuki Ishikawa, Shinichi Honiden	PID-filtered Negotiation for Decision Making in Dynamic Coverage Problem.	ICTAI	2006	DBLP DOI BibTeX RDF
23	Andrés García 0001, Adolfo Cenjor, Yoon Seok Chang, Miguel de la Fuente	An Agent-Oriented Design Methodology for RFID Improved Manufacturing Control.	ETFA	2006	DBLP DOI BibTeX RDF
23	Nazaraf Shah, Kuo-Ming Chao, Nick Godwin, Anne E. James, Chen-Fang Tsai	An Empirical Evaluation of a Sentinel Based Approach to Exception Diagnosis in Multi-Agent Systems.	AINA (1)	2006	DBLP DOI BibTeX RDF
23	Frank Dignum	Organizing Software Agents.	IBERAMIA-SBIA	2006	DBLP DOI BibTeX RDF