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.

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Information flow and cooperative control of vehicle formations

This paper presents an adaptive add-on compensator to handle a single narrow-band disturbance with unknown frequency in hard disk drives (HDDs). A disturbance observer (DOB) loop with a narrow band pass Q filter is built around the baseline servo controller to reject the narrow-band disturbance. The frequency parameter of the Q filter is directly adapted to the optimal value in the sense of minimizing the track following track mis-registration (TMR). The performance of the proposed compensator is demonstrated by simulation on an open-source realistic hard disk drive system.Copyright © 2009 by ASME

Direct Adaptive Disturbance Observer Design for Rejecting the Narrow-Band Disturbance With Unknown Frequency in Hard Disk Drives

In this paper, a concurrent design of feedforward and feedback controllers is proposed for the building thermal system. The algorithm aims at finding a balance between building occupants' thermal comfort and the energy consumption. The influence of disturbance from ambient environment and inside human activities is considered. The controller design is formulated as an optimization with feedforward and feedback controllers as two decision variables. In order to take advantage of the nearly repetitive property of the disturbances, iterative learning control (ILC) technique is utilized to reject the repetitive disturbance components. This applies to building systems in the tropics such as Singapore. For the iteration varying and unpredictable disturbance components, a feedback controller with Youla-parameterized structure is selected. To guarantee that the controllers are stabilizing and implementable in practice, stability, causality and robustness requirements along with the control saturation limit are included as constraints. The optimization is convexified via introducing new variables and relaxation. The solution to the optimization simultaneously gives the feedforward and feedback controllers to be applied in the next iteration. The proposed algorithm is demonstrated on a four-room system by simulation.

Concurrent Design of Feedforward and Feedback Controller for Building Thermal System

Adverse effects of deterministic disturbances in linear identification are pointed out. The deterministic disturbance rejector (DDR) is introduced to remove such effects in discrete-time series-parallel and parallel identification schemes for single-input, single-output systems. The method works for a class of disturbances such as a constant disturbance that can be regarded as the outputs of free systems with known dynamics.

Deterministic Disturbance Rejection in Linear Identification

Three types of models pertaining to the normal operation and icepack impact of snowploughs are presented. A general method of deriving a dynamic model for multiple blade snowploughs is developed. This model includes all the nonlinear terms against exciting dynamic models, which are derived under the assumption of small pitch motion and roll motion. A force model is developed to estimate the casting forces acting on the blade. An icepack impact model is developed to simulate the dynamic performance of the snowplough under impact caused by an icepack. Simulation shows that if the rear tire cornering stiffness may be increased, the yaw motion and the lateral motion of the snowplough can be remarkably reduced. This may enable a driver to maintain the snowplough heading through use of both steering and braking actions.

Dynamic modeling and simulation of snowplough: normal operation and icepack impact

This report presents design and experimental evaluation of lateral controllers for commuter buses based on Sliding Mode Control (SMC). The objective of the control is to track the lane centerline. SMC, a robust control technique, is selected as a nonlinear control strategy to take care of variation in longitudinal velocity. Two SMC based controllers are designed and are shown to differ only in the position of an integrator which gets naturally introduced into the closed loop. One of the methods is chosen for experimental verification because it guarantees asymptotic tracking with no chatter in the control input to the steering actuator of the vehicle.

Masayoshi Tomizuka

Papers

Direct Adaptive Disturbance Observer Design for Rejecting the Narrow-Band Disturbance With Unknown Frequency in Hard Disk Drives

Concurrent Design of Feedforward and Feedback Controller for Building Thermal System

Deterministic Disturbance Rejection in Linear Identification

Dynamic modeling and simulation of snowplough: normal operation and icepack impact

Experimental Study Of Chatter Free Sliding Mode Control For Lateral Control Of Commuter Buses In AHS