Search results for "self-reconfigurable"

Hits ?▲	Authors	Title	Venue	Year	Link	Author keywords
65	Wei Xu, Shigang Wang, An-Lin Wang, Guobao Wang	Towards an Efficient Self-organizing Reconfiguration Method for Self-reconfigurable Robots.	J. Intell. Robotic Syst.	2003	DBLP DOI BibTeX RDF	descriptive model, metamorphic rules, self-organizing, modular robots, self-reconfigurable robots
57	Esben Hallundbæk Østergaard, Kristian Kassow, Richard A. Beck, Henrik Hautop Lund	Design of the ATRON lattice-based self-reconfigurable robot.	Auton. Robots	2006	DBLP DOI BibTeX RDF	Design, Robotics, Morphology, Mechanics, Self-reconfigurable
52	Jinguo Liu, Shugen Ma, Yuechao Wang, Bin Li 0001	Network-based reconfiguration routes for a self-reconfigurable robot.	Sci. China Ser. F Inf. Sci.	2008	DBLP DOI BibTeX RDF	reconfiguration route, network-based reconfiguration, configuration network, modular robot, self-reconfigurable robot
46	Behnam Salemi, Mark Moll, Wei-Min Shen	SUPERBOT: A Deployable, Multi-Functional, and Modular Self-Reconfigurable Robotic System.	IROS	2006	DBLP DOI BibTeX RDF
45	Yanqiong Fei, Xifang Zhao	Modules Classification and Automatic Generation of Kinematics on Self-reconfigurable Modular Machines.	J. Intell. Robotic Syst.	2005	DBLP DOI BibTeX RDF	modules, kinematics, self-reconfigurable
41	Ming-Chiuan Shiu, Hou-Tsan Lee, Feng-Li Lian, Li-Chen Fu	Actuation Design of Two-Dimensional Self-Reconfigurable Robots.	SUTC	2008	DBLP DOI BibTeX RDF	Robot, Actuation, self-reconfiguration
36	Michael Rubenstein, Kenneth Payne, Peter M. Will, Wei-Min Shen	Docking Among Independent and Autonomous CONRO Self-reconfigurable Robots.	ICRA	2004	DBLP DOI BibTeX RDF
36	Jürgen Teich, Markus Köster	(Self-)reconfigurable Finite State Machines: Theory and Implementation.	DATE	2002	DBLP DOI BibTeX RDF
36	Masaru Fukushi, Susumu Horiguchi	Self-Reconfigurable Mesh Array System on FPGA.	DFT	2000	DBLP DOI BibTeX RDF
36	Ming Zhong, Mantian Li, Li-Ning Sun	Tanbot: A Self-reconfigurable Robot Enhanced with Mobility.	ICIRA (1)	2008	DBLP DOI BibTeX RDF	mobility, modularity, docking, Self-reconfigurable robot
35	Ulrik Pagh Schultz	Distributed control diffusion: towards a flexible programming paradigm for modular robots.	ROBOCOMM	2007	DBLP DOI BibTeX RDF
34	David Johan Christensen, David Brandt, Kasper Støy, Ulrik Pagh Schultz	A unified simulator for Self-Reconfigurable Robots.	IROS	2008	DBLP DOI BibTeX RDF
34	Paul White, K. Kopanski, Hod Lipson	Stochastic Self-reconfigurable Cellular Robotics.	ICRA	2004	DBLP DOI BibTeX RDF
33	Didier Keymeulen, Adrian Stoica, Ricardo Salem Zebulum, Srinivas Katkoori, Pradeep Fernando, Hariharan Sankaran, Mohammad M. Mojarradi, Taher Daud	Self-Reconfigurable Mixed-Signal Integrated Circuits Architecture Comprising a Field Programmable Analog Array and a General Purpose Genetic Algorithm IP Core.	ICES	2008	DBLP DOI BibTeX RDF	Self-Healing and Compensation, Self-reconfigurable, Field Programmable Analog Array
33	Itsuo Takanami, Tadayoshi Horita	A built-in self-reconfigurable scheme for 3D mesh arrays.	ISPAN	1997	DBLP DOI BibTeX RDF	fault tolerant 3D processor arrays, 3D mesh arrays, self-reconfigurable scheme, track switches, fault compensation, reconfiguration, reconfigurable architectures
32	Mirko Bordignon, Lars Lindegaard Mikkelsen, Ulrik Pagh Schultz	Implementing Flexible Parallelism for Modular Self-reconfigurable Robots.	SIMPAR	2008	DBLP DOI BibTeX RDF
32	Chang-Seok Choi, Hanho Lee	A Partial Self-Reconfigurable Adaptive FIR Filter System.	SiPS	2007	DBLP DOI BibTeX RDF
32	Kasper Støy, Wei-Min Shen, Peter M. Will	How to make a self-reconfigurable robot run.	AAMAS	2002	DBLP DOI BibTeX RDF
29	John H. Reif, Sam Slee	Asymptotically Optimal Kinodynamic Motion Planning for Self-reconfigurable Robots.	WAFR	2006	DBLP DOI BibTeX RDF
29	Nicholas J. Macias	The PIG Paradigm: The Design and Use of a Massively Parallel Fine Grained Self-Reconfigurable Infinitely Scalable Architecture.	Evolvable Hardware	1999	DBLP DOI BibTeX RDF
29	Ulrik Pagh Schultz, Mirko Bordignon, Kasper Støy	Robust and reversible self-reconfiguration.	IROS	2009	DBLP DOI BibTeX RDF
27	Feili Hou, Wei-Min Shen	Distributed, dynamic, and autonomous reconfiguration planning for chain-type self-reconfigurable robots.	ICRA	2008	DBLP DOI BibTeX RDF
27	Arnaud Lagger, Andres Upegui, Eduardo Sanchez, Iván González	Self-Reconfigurable Pervasive Platform for Cryptographic Application.	FPL	2006	DBLP DOI BibTeX RDF
26	Wei-Min Shen, Yimin Lu, Peter M. Will	Hormone-based control for self-reconfigurable robots.	Agents	2000	DBLP DOI BibTeX RDF	multi-agent control, collaboration, robotics, reconfiguration, autonomous agents, locomotion, gaits, self-reconfigurable robot
25	Preethi Srinivas Bhat, James Kuffner, Seth Copen Goldstein, Siddhartha S. Srinivasa	Hierarchical Motion Planning for Self-reconfigurable Modular Robots.	IROS	2006	DBLP DOI BibTeX RDF
25	Jacob Everist, Feili Hou, Wei-Min Shen	Transformation of Control in Congruent Self-Reconfigurable Robot Topologies.	IROS	2006	DBLP DOI BibTeX RDF
25	Behnam Salemi, Wei-Min Shen	Distributed Behavior Collaboration for Self-reconfigurable Robots.	ICRA	2004	DBLP DOI BibTeX RDF
25	Forrest H. Bennett III, Eleanor Gilbert Rieffel	Design of Decentralized Controllers for Self-Reconfigurable Modular Robots Using Genetic Programming.	Evolvable Hardware	2000	DBLP DOI BibTeX RDF
22	David Johan Christensen, David Brandt, Ulrik Pagh Schultz, Kasper Støy	Neighbor detection and crosstalk elimination in self-reconfigurable robots.	ROBOCOMM	2007	DBLP DOI BibTeX RDF
22	Haruhisa Kurokawa, Kohji Tomita, Akiya Kamimura, Shigeru Kokaji, Takashi Hasuo, Satoshi Murata	Self-reconfigurable modular robot M-TRAN: distributed control and communication.	ROBOCOMM	2007	DBLP DOI BibTeX RDF	coordinated motion control, distributed autonomous system, central pattern generator
22	Fabio Cancare, Marco D. Santambrogio, Donatella Sciuto	An application-centered design flow for self reconfigurable systems implementation.	ASP-DAC	2009	DBLP DOI BibTeX RDF
22	Andreas Schallenberg, Wolfgang Nebel, Frank Oppenheimer	OSSS+R: Modelling and Simulating Self-Reconfigurable Systems.	FPL	2006	DBLP DOI BibTeX RDF
22	Samir Saidani	Self-reconfigurable Robots Topodynamic.	ICRA	2004	DBLP DOI BibTeX RDF
21	Guifang Qiao, Guangming Song, Jun Zhang 0030, Hongtao Sun, Jian Ge, Weiguo Wang	Design of a self-reconfigurable wireless network system for modular self-reconfigurable robots.	ROBIO	2012	DBLP DOI BibTeX RDF
20	Kimon Karras, Elias S. Manolakos	An embedded dynamically self-reconfigurable Master-Slaves MPSoC architecture.	FPL	2008	DBLP DOI BibTeX RDF
20	Iván González 0004, Estanislao Aguayo, Sergio López-Buedo	Self-Reconfigurable Embedded Systems on Low-Cost FPGAs.	IEEE Micro	2007	DBLP DOI BibTeX RDF	reconfigurable hardware, real-time and embedded systems, special-purpose and application-based systems, algorithms implemented in hardware
20	Ricardo Salem Zebulum, Mohammad M. Mojarradi, Adrian Stoica, Didier Keymeulen, Taher Daud	Self-Reconfigurable Analog Arrays: Off-The Shelf Adaptive Electronics for Space Applications.	AHS	2007	DBLP DOI BibTeX RDF
20	Satoshi Murata, Akiya Kamimura, Haruhisa Kurokawa, Eiichi Yoshida, Kohji Tomita, Shigeru Kokaji	Self-Reconfigurable Robots: Platforms for Emerging Functionality.	Embodied Artificial Intelligence	2003	DBLP DOI BibTeX RDF
19	Roderich Groß, Michael Bonani, Francesco Mondada, Marco Dorigo	Autonomous Self-Assembly in Swarm-Bots.	IEEE Trans. Robotics	2006	DBLP DOI BibTeX RDF
19	Janusz A. Starzyk, Yongtao Guo, Zhineng Zhu	Dynamically Reconfigurable Neuron Architecture for the Implementation of Self-Organizing Learning Array.	IPDPS	2004	DBLP DOI BibTeX RDF
18	Yaochu Jin, Yan Meng	Morphogenetic Robotics: A New Paradigm for Designing Self-Organizing, Self-Reconfigurable and Self-Adaptive Robots.	Morphogenetic Engineering, Toward Programmable Complex Systems	2012	DBLP DOI BibTeX RDF
18	Yu-chen Ho, Ching-Hu Lu, Yi-Han Chen, Shih-Shinh Huang, Ching-Yao Wang, Li-Chen Fu	Active-learning assisted self-reconfigurable activity recognition in a dynamic environment.	ICRA	2009	DBLP DOI BibTeX RDF
18	Byoung Kwon An	Em-cube: cube-shaped, self-reconfigurable robots sliding on structure surfaces.	ICRA	2008	DBLP DOI BibTeX RDF
18	Andres Upegui, Eduardo Sanchez	Evolving Hardware with Self-reconfigurable connectivity in Xilinx FPGAs.	AHS	2006	DBLP DOI BibTeX RDF
18	Qiu-xuan Wu, Ya-hui Wang, Guang-Yi Cao, Yan-qiong Fei	Locomotion Control of Distributed Self-reconfigurable Robot Based on Cellular Automata.	ICIC (2)	2005	DBLP DOI BibTeX RDF
18	Nicolas Brener, Faïz Ben Amar, Philippe Bidaud	Analysis of Self-reconfigurable Modular Systems: a Design Proposal for Multi-modes Locomotion.	ICRA	2004	DBLP DOI BibTeX RDF
18	Michael G. Lorenz, Luis Mengibar, Luis Entrena, Raul Sánchez-Reillo	Data Processing System With Self-reconfigurable Architecture, for Low Cost, Low Power Applications.	FPL	2003	DBLP DOI BibTeX RDF
18	Hatem M. El-Boghdadi, Ramachandran Vaidyanathan, Jerry L. Trahan, Suresh Rai	On the Communication Capability of the Self-Reconfigurable Gate Array Architecture.	IPDPS	2002	DBLP DOI BibTeX RDF	Segmentable Bus, FPGAs, Communication complexity, Run-time Reconfiguration, Self Reconfiguration
18	Ying Zhang, Kimon Roufas, Craig Eldershaw, Mark Yim, David Duff	Sensor Computations in Modular Self Reconfigurable Robots.	ISER	2002	DBLP DOI BibTeX RDF
18	Forrest H. Bennett III, Brad Dolin, Eleanor Gilbert Rieffel	Programmable Smart Membranes: Using Genetic Programming to Evolve Scalable Distributed Controllers for a Novel Self-Reconfigurable Modular Robotic Application.	EuroGP	2001	DBLP DOI BibTeX RDF
18	Hristo Bojinov, Arancha Casal, Tad Hogg	Multiagent Control of Self-Reconfigurable Robots.	ICMAS	2000	DBLP DOI BibTeX RDF
17	Pierre Thalamy	Distributed algorithms and advanced modeling approaches for fast and efficient object construction using a modular self-reconfigurable robotic system. (Algorithmes distribués et méthodes de modélisation avancées pour une construction rapide et efficace d'objets avec un robot modulaire auto-reconfigurable).		2020	RDF
17	Zack Butler 0001, Eric Fabricant	Reconfigurable Teams: Cooperative Goal Seeking with Self-Reconfigurable Robots.	DARS	2008	DBLP DOI BibTeX RDF
17	David Brandt	Comparison of A and RRT-Connect Motion Planning Techniques for Self-Reconfiguration Planning.	IROS	2006	DBLP DOI BibTeX RDF
17	Susumu Horiguchi, Issei Numata	Self-Reconfiguration Scheme of 3D-Mesh Arrays.	DFT	1998	DBLP DOI BibTeX RDF	3D-Mesh Arrays, the recursive shift scheme, 3D stacked implementation, massively parallel computers, Reconfiguration Scheme
16	Jens Hagemeyer, Boris Kettelhoit, Markus Koester, Mario Porrmann	A Design Methodology for Communication Infrastructures on Partially Reconfigurable FPGAs.	FPL	2007	DBLP DOI BibTeX RDF
16	Leandro Möller, Rafael Soares, Ewerson Carvalho, Ismael Grehs, Ney Calazans, Fernando Moraes 0001	Infrastructure for dynamic reconfigurable systems: choices and trade-offs.	SBCCI	2006	DBLP DOI BibTeX RDF	reconfigurable architectures, NoCs, configuration controllers
16	David H. Albonesi	Mixing It Up.	IEEE Micro	2007	DBLP DOI BibTeX RDF	photonic integration, self-reconfigurable hardware, simulation
16	Wei-Min Shen, Maks Krivokon, Harris Chi Ho Chiu, Jacob Everist, Michael Rubenstein, Jagadesh Venkatesh	Multimode locomotion via SuperBot reconfigurable robots.	Auton. Robots	2006	DBLP DOI BibTeX RDF	Multifunctional and Self-reconfigurable robots, Multimode gaits, Modular, Space robots
14	Kasper Støy	How to Construct Dense Objects with Self-Recondfigurable Robots.	EUROS	2006	DBLP DOI BibTeX RDF
14	Petras Swissler, Michael Rubenstein	FireAntV3: A Modular Self-Reconfigurable Robot Toward Free-Form Self-Assembly Using Attach-Anywhere Continuous Docks.	IEEE Robotics Autom. Lett.	2023	DBLP DOI BibTeX RDF
14	Dongyang Bie, Yu Zhang 0045, Xingang Zhao, Yanhe Zhu	A Bio-inspired Self-reparation Approach for Lattice Self-reconfigurable Modular Robots.	ICIRA (1)	2019	DBLP DOI BibTeX RDF
14	Reem Alattas	Evolutionary Modular Self-Assembly and Self-Reconfigurable Robotics: Exhaustive Review.	CoRR	2017	DBLP BibTeX RDF
14	Yanqiong Fei, Chengyuan Wang	Self-Repairing Algorithm of Lattice-Type Self-Reconfigurable Modular Robots.	J. Intell. Robotic Syst.	2014	DBLP DOI BibTeX RDF
14	Masayoshi Mitsui, Atsushi Masumori, Ryo Asakura, Hiroya Tanaka	Applying Self-Assembly and Self-Reconfigurable Systems for Printer.	ALIFE	2014	DBLP DOI BibTeX RDF
14	Guanhong Pei, Binoy Ravindran, E. Douglas Jensen	Self-organizing and self-reconfigurable event routing in ad hoc networks with causal dependency awareness.	ACM Trans. Auton. Adapt. Syst.	2011	DBLP DOI BibTeX RDF
14	Jie Zhao 0003, Xindan Cui, Yanhe Zhu, Shufeng Tang	A new self-reconfigurable modular robotic system UBot: Multi-mode locomotion and self-reconfiguration.	ICRA	2011	DBLP DOI BibTeX RDF
14	Voicu Groza, Rami S. Abielmona, Mansour H. Assaf, Mohammed Elbadri, Mohammad El-Kadri, Arkan Khalaf	A Self-Reconfigurable Platform for Built-In Self-Test Applications.	IEEE Trans. Instrum. Meas.	2007	DBLP DOI BibTeX RDF
14	David Johan Christensen	Evolution of Shape-changing and Self-repairing Control for the ATRON Self-reconfigurable Robot.	ICRA	2006	DBLP DOI BibTeX RDF
14	Behrokh Khoshnevis, Peter M. Will, Wei-Min Shen	Highly compliant and self-tightening docking modules for precise and fast connection of self-reconfigurable robots.	ICRA	2003	DBLP DOI BibTeX RDF
14	Wei-Min Shen, Peter M. Will, Berok Khoshnevis	Self-assembly in space via self-reconfigurable robots.	ICRA	2003	DBLP DOI BibTeX RDF
14	Yugang Liu, Guangjun Liu	Mobile manipulation using tracks of a tracked mobile robot.	IROS	2009	DBLP DOI BibTeX RDF
14	Fernando J. Barros	Modeling and simulation of parallel adaptive divide-and-conquer algorithms.	J. Supercomput.	2008	DBLP DOI BibTeX RDF	Dynamic structure models, Simulation, Adaptive algorithms
14	Enrique Cantó, Francesc Fons, Mariano López	Self-recofigurable embedded systems on Spartan-3.	FPL	2008	DBLP DOI BibTeX RDF
14	Kurt Franz Ackermann, Burghard Hoffmann, Leandro Soares Indrusiak, Manfred Glesner	Enabling self-reconfiguration on a video processing platform.	SIES	2008	DBLP DOI BibTeX RDF
14	Masafumi Yamashita	Robots and Molecules.	SSS	2007	DBLP DOI BibTeX RDF
14	Wei Chen 0003, Islam A. K. M. Muzahidul, Mohan Malkani, Amir Shirkhodaie, Koichi Wada 0001, Mohamed Zein-Sabatto	Novel Broadcast/Multicast Protocols for Dynamic Sensor Networks.	IPDPS	2007	DBLP DOI BibTeX RDF
14	Jorge Peña 0001, Andres Upegui, Eduardo Sanchez	Particle Swarm Optimization with Discrete Recombination: An Online Optimizer for Evolvable Hardware.	AHS	2006	DBLP DOI BibTeX RDF
12	Xuesong Yan, Chen Shi, Lishan Kang, Shitan Huang	An Architecture Design for Evolvable Computer.	ISICA	2008	DBLP DOI BibTeX RDF
12	Liping Zhang 0006, Shugen Ma, Bin Li 0001, Zheng Zhang 0017, Zaili Dong, Binggang Cao	Position-sensing based a new docking system of RPRS.	ICARCV	2004	DBLP DOI BibTeX RDF
10	Rakesh Das, Jitendra Nath Bera	Self-reconfigurable partial mesh using ZigBee control board towards fail-proof and reliable home area networking.	Ad Hoc Networks	2024	DBLP DOI BibTeX RDF
10	Isira D. Wijegunawardana, M. A. Viraj J. Muthugala, S. M. Bhagya P. Samarakoon, Ong Jun Hua, Saurav Ghante Anantha Padmanabha, Mohan Rajesh Elara	Insights from autonomy trials of a self-reconfigurable floor-cleaning robot in a public food court.	J. Field Robotics	2024	DBLP DOI BibTeX RDF
10	Yuwei Zhang, Sinan Oguz, Shaoping Wang, Emanuele Garone, Xingjian Wang, Marco Dorigo, Mary Katherine Heinrich	Self-Reconfigurable Hierarchical Frameworks for Formation Control of Robot Swarms.	IEEE Trans. Cybern.	2024	DBLP DOI BibTeX RDF
10	Duy Nam Bui, Manh Duong Phung, Hung Pham Duy	Self-Reconfigurable V-shape Formation of Multiple UAVs in Narrow Space Environments.	CoRR	2024	DBLP DOI BibTeX RDF
10	Madan Mohan Rayguru, Spandan Roy, Lim Yi, Mohan Rajesh Elara, Simone Baldi	Introducing Switched Adaptive Control for Self-Reconfigurable Mobile Cleaning Robots.	IEEE Trans Autom. Sci. Eng.	2024	DBLP DOI BibTeX RDF
10	Duy Nam Bui, Manh Duong Phung, Hung Pham Duy	Self-Reconfigurable V-Shape Formation of Multiple UAVs in Narrow Space Environments.	SII	2024	DBLP DOI BibTeX RDF
10	Aliah Majed, Hassan Harb, Abbass Nasser, Benoit Clement	RUN: a robust cluster-based planning for fast self-reconfigurable modular robotic systems.	Intell. Serv. Robotics	2023	DBLP DOI BibTeX RDF
10	Luiza Labazanova, Shuang Peng 0014, Liuming Qiu, Hoi-Yin Lee, Thrishantha Nanayakkara, David Navarro-Alarcon	Self-Reconfigurable Soft-Rigid Mobile Agent With Variable Stiffness and Adaptive Morphology.	IEEE Robotics Autom. Lett.	2023	DBLP DOI BibTeX RDF
10	Halil Ibrahim Dokuyucu, Nurhan Gürsel Özmen	Achievements and future directions in self-reconfigurable modular robotic systems.	J. Field Robotics	2023	DBLP DOI BibTeX RDF
10	Renpeng Zou, Xixiang Lyu, Jing Ma, Bowen Zhang, Danfang Wu	BCMIX: A Blockchain-Based Dynamic Self-Reconfigurable Mixnet.	IEEE/ACM Trans. Netw.	2023	DBLP DOI BibTeX RDF
10	Yuxiao Tu, Tin Lun Lam	Configuration Identification for a Freeform Modular Self-Reconfigurable Robot - FreeSN.	IEEE Trans. Robotics	2023	DBLP DOI BibTeX RDF
10	Rahmi Ilker Kayaalp, Mehmet Ugras Cuma, Mehmet Tümay	A new rule-based self-reconfigurable energy management control of grid and batteries connected hybrid regenerative solar power system for critical loads.	Simul. Model. Pract. Theory	2023	DBLP DOI BibTeX RDF
10	Xindan Cui, Yanhe Zhu, Jie Zhao 0003, Songhao Piao, Erfu Yang	Bio-inspired Locomotion Control for UBot Self-reconfigurable Modular Robot.	ICCAD	2023	DBLP DOI BibTeX RDF
10	Benoît Piranda, Frédéric Lassabe, Julien Bourgeois	DisCo: A Multiagent 3D Coordinate System for Lattice Based Modular Self-Reconfigurable Robots.	ICRA	2023	DBLP DOI BibTeX RDF
10	Aurélien Morel, Anastasia Bolotnikova, Celinna Ju, Jan M. Rabaey, Auke Jan Ijspeert	End-to-End Planner for Self-Reconfigurable Modular Robots Collaborative Objects Manipulation, Transport and Handover to Human Application.	RO-MAN	2023	DBLP DOI BibTeX RDF
10	Abdallah Makhoul, Jad Bassil	Fault Tolerance Technique Using Bidirectional Hetero-Associative Memory for Self-Reconfigurable Programmable Matter.	IWCMC	2023	DBLP DOI BibTeX RDF
10	Weihao Wang, Edwardo E. Fukushima, Naoyuki Kubota	Design and Implementation of a Modular Self-reconfigurable Spherical Robot Connected by Magnetic Force.	ICIRA (9)	2023	DBLP DOI BibTeX RDF
10	Aliah Majed, Hassan Harb, Abbass Nasser, Benoit Clement	FSET: Fast Structure Embedding Technique for Self-reconfigurable Modular Robotic Systems.	AINA (2)	2023	DBLP DOI BibTeX RDF
10	Anh Vu Le, Veerajagadheswar Prabakaran, Yuyao Shi, Rajesh Elara Mohan, Min Yan Naing, Tan Nhat Nguyen, Van Duc Phan, Minh Bui Vu	Long-term trials for improvement of autonomous area coverage with a Tetris inspired tiling self-reconfigurable system.	Expert Syst. Appl.	2022	DBLP DOI BibTeX RDF
10	Shashank, Indu Sreedevi	Distributed Network of Adaptive and Self-Reconfigurable Active Vision Systems.	Symmetry	2022	DBLP DOI BibTeX RDF