There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

While the Transformer architecture has become the de-facto standard for natural language processing tasks, its applications to computer vision remain limited. In vision, attention is either applied in conjunction with convolutional networks, or used to replace certain components of convolutional networks while keeping their overall structure in place. We show that this reliance on CNNs is not necessary and a pure transformer applied directly to sequences of image patches can perform very well on image classification tasks. When pre-trained on large amounts of data and transferred to multiple mid-sized or small image recognition benchmarks (ImageNet, CIFAR-100, VTAB, etc.), Vision Transformer (ViT) attains excellent results compared to state-of-the-art convolutional networks while requiring substantially fewer computational resources to train.

An Image is Worth 16x16 Words: Transformers for Image Recognition at Scale

From the Publisher:
This book explores the meta-heuristics approach called tabu search, which is dramatically changing our ability to solve a hostof problems that stretch over the realms of resource planning,telecommunications, VLSI design, financial analysis, scheduling, spaceplanning, energy distribution, molecular engineering, logistics,pattern classification, flexible manufacturing, waste management,mineral exploration, biomedical analysis, environmental conservationand scores of other problems. The major ideas of tabu search arepresented with examples that show their relevance to multipleapplications. Numerous illustrations and diagrams are used to clarifyprinciples that deserve emphasis, and that have not always been wellunderstood or applied. The book's goal is to provide ''hands-on' knowledge and insight alike, rather than to focus exclusively eitheron computational recipes or on abstract themes. This book is designedto be useful and accessible to researchers and practitioners inmanagement science, industrial engineering, economics, and computerscience. It can appropriately be used as a textbook in a masterscourse or in a doctoral seminar. Because of its emphasis on presentingideas through illustrations and diagrams, and on identifyingassociated practical applications, it can also be used as asupplementary text in upper division undergraduate courses. 

Finally, there are many more applications of tabu search than canpossibly be covered in a single book, and new ones are emerging everyday. The book's goal is to provide a grounding in the essential ideasof tabu search that will allow readers to create successfulapplications of their own. Along with the essentialideas,understanding of advanced issues is provided, enabling researchers togo beyond today's developments and create the methods of tomorrow.

Tabu Search

We consider the problem of cooperation among a collection of vehicles performing a shared task using intervehicle communication to coordinate their actions. Tools from algebraic graph theory prove useful in modeling the communication network and relating its topology to formation stability. We prove a Nyquist criterion that uses the eigenvalues of the graph Laplacian matrix to determine the effect of the communication topology on formation stability. We also propose a method for decentralized information exchange between vehicles. This approach realizes a dynamical system that supplies each vehicle with a common reference to be used for cooperative motion. We prove a separation principle that decomposes formation stability into two components: Stability of this is achieved information flow for the given graph and stability of an individual vehicle for the given controller. The information flow can thus be rendered highly robust to changes in the graph, enabling tight formation control despite limitations in intervehicle communication capability.

/pdf/information-flow-and-cooperative-control-of-vehicle-4ws61wioze.pdf

Information flow and cooperative control of vehicle formations

A new control approach for a class of multivariable nonlinear systems whose decoupling matrix is singular is presented. For this class of systems, local decoupling may be achieved by dynamic compensation. Instead of decoupling the nonlinear system by adding chains of integrators in the input channels, we modify the dynamic extension algorithm by incorporating backstepping design methods to partially close the loop in each design step. The resulting control law by this new approach is a static state feedback law. Although the final closed loop form of the nonlinear system is not decoupled, each output is controlled to the desired value asymptotically. A design example is given to illustrate this approach.

Control of a class of multivariable nonlinear systems without vector relative degrees: a backstepping approach

This paper describes the technical challenges and the application of advanced control methodologies to meet the challenges in the design of servo systems for data storage devices such as hard disk drives (HDDs). Though an emphasis is on control applications to hard disk drives, the challenges and methodologies are broadly applicable to other precision machines. "Mechatronics" in the title emphasizes that the design of control algorithms for modern machines is not an isolated activity by control engineers in the development of products, which is indeed a synergistic integration of mechanical hardware design, sensor and actuator selections and control algorithms.

Mechatronics for computer data storage devices

Some high speed color printers require that the sheets be accurately controlled in order to achieve a precise alignment of colors. To accomplish this goal a steerable nips mechanism has been proposed as the actuator. This steerable nips mechanism allows the sheet to be precisely controlled in longitudinal, lateral and skew directions. In this paper we develop a control strategy based on hybrid automata that precisely controls the position of the sheet. This hybrid control law has four finite states among which the system switches during the trajectories tracking process. Switching from one state to another is necessary since the normal control mode cannot be used when the trajectory being tracked requires the wheels to have zero angular velocity. The proposed controller is able to move the sheet from an initial position at rest to an arbitrary final position also at rest. The system model is nonlinear and subject to four nonholonomic constraints. Two of these constraints come from the fact that the velocities perpendicular to the wheels must be zero, and the other two constraints are due to the no-slip condition.

/pdf/full-paper-sheet-control-using-hybrid-automata-ogvr7i1rlx.pdf

Full Paper Sheet Control Using Hybrid Automata

Author(s): Liu, Changliu | Advisor(s): Tomizuka, Masayoshi | Abstract: Human-robot interactions (HRI) have been recognized to be a key element of future robots in many application domains such as manufacturing, transportation, service and entertainment. These applications entail huge social and economical impacts. Future robots are envisioned to function as human's counterparts, which are independent entities that make decisions for themselves; intelligent actuators that interact with the physical world; and involved observers that have rich senses and critical judgements. Most importantly, they are entitled social attributions to build relationships with humans. We call these robots co-robots.Technically, it is challenging to design the behavior of co-robots. Unlike traditional robots that work in structured and deterministic environments, co-robots need to operate in highly unstructured and stochastic environments. The fundamental research question to address in this dissertation is how to ensure that co-robots operate efficiently and safely in dynamic uncertain environments.The focus of this dissertation is 1) to set up a unified analytical framework for various human-robot systems; 2) to establish a methodology to design the robot behavior to address the fundamental problem. A multi-agent framework to model human-robot systems is introduced in Chapter 2. In order to address the uncertainties during human-robot interactions, a unique parallel planning and control architecture is introduced in Chapter 2, which has a cognition module for human behavior estimation and human motion prediction, a long term global planner to ensure efficiency of robot behavior, and a short term local planner to ensure real time safety under uncertainties. The functionalities of these components are discussed in Chapter 3 to Chapter 5. Chapter 3 discusses the cognition module, which includes offline classification and online adaptation of various human behaviors. Chapter 4 and Chapter 5 discuss the optimal control or optimization problems for short term and long term robot motion planning. In a cluttered environment, the optimization problems are highly nonlinear and non-convex, hence hard to solve in real time, which may delay the robot's response in emergency situations. Fast online algorithms are developed to handle the issue: the convex feasible set algorithm (CFS) for the long term optimization, and the safe set algorithm (SSA) for the short term optimization. In particular, the CFS algorithm transforms the non-convex optimization problem into a sequence of convex optimization problems that can be solved efficiently online, which converges in fewer iterations and runs faster than conventional non-convex optimization solvers as shown in Chapter 6. A method for theoretical evaluation of the designed behaviors is discussed in Chapter 7. The experimental platforms to evaluate the design are discussed in Appendix A. Applications of the proposed method on different co-robots are discussed in Chapter 8 and Chapter 9. Chapter 8 illustrates the application on automated vehicles in the framework of the robustly safe automated driving (ROAD) system. Chapter 9 discusses the application on industrial collaborative robots in the framework of the robot safe interaction system (RSIS).

Designing Robot Behavior in Human-Robot Interactions

http://www.nt.ntnu.no/users/skoge/prost/proceedings/ifac11-proceedings/data/html/papers/0669.pdf

Masayoshi Tomizuka

Papers

Control of a class of multivariable nonlinear systems without vector relative degrees: a backstepping approach

Mechatronics for computer data storage devices

Full Paper Sheet Control Using Hybrid Automata

Designing Robot Behavior in Human-Robot Interactions

A Gait Rehabilitation Strategy Inspired by an Iterative Learning Algorithm