• International Journal of Contents
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• v.5 no.2
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• pp.53-58
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• 2009

This paper presents a novel approach in the design of a CAM for an asynchronous cache. The architecture of cache mainly consists of four units: control logics, content addressable memory, completion signal logic units and instruction memory. The pseudo-DCVSL is useful to make a completion signal which is a reference for handshake control. The proposed CAM is a very simple extension of the basic circuitry that makes a completion signal based on DI model. The cache has 2.75KB CAM for 8KB instruction memory. We designed and simulated the proposed asynchronous cache including CAM. The results show that the cache hit ratio is up to 95% based on pseudo-LRU replacement policy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.5
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• pp.1604-1617
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• 2014

This paper proposes RIX-MAC (Receiver-Initiated X-MAC), a new energy-efficient MAC protocol based on an asynchronous duty cycling. RIX-MAC improves energy efficiency through utilizing short preambles and adopting the receiver-initiated approach, where RIX-MAC minimizes sender nodes' energy consumption by enabling transmitters to predict receiver nodes' wake-up times. It also reduces receiver nodes' energy consumption by decreasing the number of control frames. We use the network simulator to evaluate RIX-MAC's performance. Compared to the prior asynchronous duty cycling approaches of X-MAC and PW-MAC, the proposed protocol shows a remarkable improvement in energy-efficiency and end-to-end delay.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.7
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• pp.501-508
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• 2004

In this paper, a coordinated scheduling algorithm is proposed to reduce end-to-end delay in distributed control of systems. For the algorithm, the analysis of practical end-to-end delay in the worst case is performed priory with considering implementation of the systems. The end-to-end delay is composed of the delay caused by multi-task scheduling of operating systems, the delay caused by network communications, and the delay caused by asynchronous timing between operating systems and network communications. Through some simulation tests based on CAN(Controller Area Network), the proposed worst case end-to-end delay analysis is validated. Through the simulation tests, it is also shown that a real-time distributed control system designed to existing worst case delay cannot guarantee end-to-end time constraints. With the analysis, a coordinated scheduling algorithm is proposed here. The coordinated scheduling algorithm is focused on the reduction of the delay caused by asynchronous timing between operating systems and network communications. Online deadline assignment strategy is proposed for the scheduling. The performance enhancement of the distributed control systems by the scheduling algorithm is shown through simulation tests.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.9
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• pp.47-54
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• 2000

We designed asynchronous event logic library with 0.25um CMOS technology and interface chip for heterogeneous system with high-speed asynchronous FIFO operating at 1.6GHz. Optimized asynchronous standard cell layouts and Verilog models are designed for top-down design methodology. A Method for mitigating a design bottleneck when it comes to tolerate clock skew is described. This communication scheme using clock control circuits, which is used for the free of synchronization failures, is analyzed and implemented. With clock control circuit and FIFO, high-speed communication between synchronous modules operating at different clock frequencies or with asynchronous modules is performed. The core size of implemented high-speed 32bit-interface chip for heterogeneous system is about $1.1mm{\times}1.1mm$.

• Journal of the Korean Society of Safety
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• v.12 no.3
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• pp.67-75
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• 1997

This paper presents a study on the application of Asynchronous Team(A-Team) theory for QVC(Reactive power control) and security assessment in a power system. Reactive power control problem is the one of optimally establishing voltage level given reactive power sources, which is very important problem to supply the demand without interruption and needs methods to alleviate a bus voltage limit violation more quickly. It can be formulated as a mixed-integer linear programming(MILP) problem without deteriorating of solution accuracy to a certain extent. The security assessment is to estimate the relative robustness of the system and deterministic approach based on AC load flow calculations is adopted to assess it, especially voltage security. A distance measure, as a measurement for voltage security, is introduced. In order to analyze the above two problem, reactive power control and static security assessment, In an integrated fashion, a new organizational structure, called an A-team, is adopted. An A-team is well-suited to the development of computer-based, multi-agent systems for operation of large-scaled power systems. In order to verify the usefulness of the suggested scheme herein, modified IEEE 30 bus system is employed as a sample system. The results of a case study are also presented.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.9
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• pp.173-181
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• 2014

This paper addresses the problem of model matching control for a class of systems modeled as input/output asynchronous sequential machines. Based on the feedback control scheme, we design a corrective controller that compensates the behavior of the closed-loop system so as to match a reference model. Whereas the former studies use state observers and the output burst for designing a controller, the present research needs neither the observer nor the output burst in controller design. We define the 'output equivalent machine' of the considered machine to describe the existence condition and the construction algorithm for the proposed controller. A case study is provided to show the operation of the proposed corrective controller.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2684-2686
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• 2000

This paper describes a preliminary study on a modeling technique for control performance evaluation of asynchronous TMR(Triple Modular Redundancy) controller. Hybrid system modeling is applied to TMR controller performance evaluation and mixed logical dynamical system description is used to model the behavior of majority voter in the controller. Windup and bumpless transfer problems in redundancy controls are also mentioned.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.427-430
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• 2010

MOST Network는 오디오와 비디오 데이터를 실시간으로 전송하는 동기식데이터 영역과 패킷데이터를 전송하는 비동기식 데이터 영역, 네트워크 관리를 위한 명령, 상태, 진단 정보를 전송하는 control Channel로 구성되어 있다. 본 논문에서는 비동기식 데이터 영역과 Control Channel의 데이터를 캡처 및 분석하는 모듈을 설계 및 구현한 후 실제 MOST 네트워크를 구축하여 검증해 보았다. 구현한 시스템을 바탕으로 고가의 장비를 별도로 보유하지 않더라도 MOST Network의 비동기식 데이터 영역과 Control Channel의 데이터를 확인할 수 있으며, 분석이 가능한 시스템을 제안하였다.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.2985-2995
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• 1997

In this paper, we proposed the "synchronous & asynchronous distance education system" which is able to interact among teachers and students for open education in cyberspace, and it is based telecommunication technology and multimedia technology. Specially, This system gets rid of the nufamiliarity and inconvenient feeling during the distance education. Also it supports the mediation of floor mode, for a group lecture and supports the synchronous mode for face-to-face effective and asynchronous mode for self-learning. The asynchronous mode has the down load function and the consultant mode (between teacher and student). The element technologies of this system consists of application sharing technique, whiteboard, various video window display, audio support, user interface, environment setup, session management, access control, network control and media control for collaborative distance education.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.884-887
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• 2023

Recently, research has been actively conducted to overcome the limitations of high-priced single sensors and reduce costs through the convergence of low-cost multi-variable sensors. This paper estimates state variables through asynchronous Kalman filters constructed using CVXPY and uses Cvxpylayers to compare and learn state variables estimated from CVXPY with true value data to estimate filter parameters of low-cost sensors fusion.