• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.73-80
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• 2008

ALINEA algorithm, which is one of the best on-ramp metering algorithms, was designed to control the traffic volume from on-ramp in order to maintain the optimal occupancy rate of the detectors installed downstream of the merge area. But, the reliability of occupancy rate estimated from the loop detectors, which are used most commonly in Korea, is relatively lower than other parameters such as speed and volume. Moreover, because occupancy rate depends on the length of loop detectors and site, lots of calibration work is required whenever they are installed in order to estimate the occupancy rate. Therefore, there exists room for improvement of ALINEA algorithm because only occupancy rate having some problems is considered as a control parameter in ALINEA algorithm. Practically it is difficult to measure or perceive the occupancy rate for traffic engineers and drivers. On the other hand, speed can be good alternative which can overcome the defect induced by using occupancy. In this study, occupancy based ALINEA algorithm is converted to speed based ALINEA assuming the linear relationship between density and speed.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.113-114
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• 2016

영구자석형 동기전동기를 구동하는 인버터에서는 기본적으로 정현파 운전 방식을 사용하지만 최근에는 구형파 운전 방식도 종종 사용되고 있다. 정현파 운전 방식은 구형파 운전 방식에 비해 토크 리플이 작고 기동 성능이 우수하며, 약자속 제어를 이용하여 정격 속도 이상의 고속 운전이 가능하다. 이에 비해 구형파 운전 방식은 제어 알고리즘이 간단하고 스위칭 손실이 적은 장점이 있지만, 토크 리플이 크고 정격 속도 이하의 영역에서만 운전이 가능하다는 단점이 있다. 최근에 인버터의 운전 중에 각각의 장점이 있는 이들 2가지 운전 방식을 서로 전환하는 방법으로 가전제품의 압축기와 같은 연속 부하에 적용하기 위한 연구가 진행되었다. 저속 구간에서는 스위칭 손실을 줄이기 위하여 구형파 운전 방식을 주로 사용하고, 고속 구간에서는 안정적인 제어 성능을 위하여 정현파 운전 방식을 사용한다. 또한, 이 2가지 운전 방식의 전환 구간에서의 발생되는 과도 상태를 짧게 줄이기 위하여 속도 및 전류 제어기의 제어 변수에 대한 초기화 방법이 제시되었다. 본 논문에서는 구형파 운전 구간의 속도 제어기에 비례 적분 전류 제어기를 추가하여 전류 리플을 감소시키고, 전환 구간에서의 속도 및 전류 제어기의 제어 변수에 대한 초기화 방법을 제시하였다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.3
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• pp.15-21
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• 2009

In this paper, we consider the design problem of robust stabilization and robust guaranteed cost state feedback controller for discrete-time singular systems with parameter uncertainties by LMI(linear matrix inequality) approach without semi-definite condition and decomposition of system matrices. The objective of robust stabilization controller is to construct a state feedback controller such that the closed-loop system is regular, causal, and stable. In the case of robust guaranteed cost control, the optimal value of guaranteed cost and controller design method are presented on the basis of robust stabilization control technique. Finally, a numerical example is provided to show the validity of the design methods.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.3
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• pp.103-110
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• 2016

A performance analysis program of a disk type fluidic valve was developed to predict a chamber pressure and a response time. A parametric study of this device was performed by using scattering plot method. A sensitivity of Mach number at a nozzle outlet showed the highest value about a outlet diameter of nozzle. An inlet flow rate is the most important parameter to design the fluidic valve because it has high sensitivity value both a outlet velocity and a response time.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.151-156
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• 2017

Communication performance requirements are described as QoS parameters in multimedia communication Protocols including SCTP. One of the important QoS parameters is the reliability of the transfer. As a QoS parameter, the reliability defines error detection, report and correction mechanisms. Including SCTP, conventional error control mechanisms, however, do not consider the integrated viewpoint of multimedia data. In this paper, I have designed and proposed the multimedia oriented error control method based on multimedia characteristics. The proposed scheme should have the reduction effect of the communication resources such as frame buffer, procesing power and bandwidth as well as satisfy the requirements of users.

• Journal of the Korean Institute of Gas
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• v.3 no.1
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• pp.64-74
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• 1999

Using the steady state gains, an appropriate criterion used for the interaction analysis among variables and the loop pairing is suggested. Based upon the suggested criterion derived from the derivative relation of implicit function, the SISO pairing which has minimum interaction among control system variables and good control performance can be determined. The relative effect among diagonal gains and off-diagona gains, which was not considered in other criteria, can be explained deterministically Also, the criterion can be easily applied to partial MIMO pairing. This criterion was applied to several examples to illustrate its usefulness in finding the feasible SISO pairing and MIMO pairing

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.491-499
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• 2007

In this paper, we present a design method of the ternary logic circuits based on Reed-Muller expansions. The design method of the presented ternary logic circuits checks the degree of each variable for the coefficients of Reed-Holler Expansions(RME) and determines the order of optimal control input variables that minimize the number of Reed-Muller Expansions modules. The order of optimal control input variables is utilized the computation of circuit cost matrix. The ternary logic circuits of the minimized tree structures to be constructed by RME modules based on Reed-Muller Expansions are realized using the computation results of its circuit cost matrix. This method is only performed under unit time in order to search for the optimal control input variables. Also, this method is able to be programmed by computer and the run time on programming is $3^n$.

• ICROS
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• v.6 no.3
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• pp.68-81
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• 2000

본 논문에서는 최근 10여년간 세계적으로 많은 관심과 더불어 비약적인 연구발전을 이루어 온 이산사건시스템의 관리제어에 있어서 기본적인 이산사건모델링과 관리제어이론을 설명하고최근의 연구동향 등을 소개한다. 또한 기존의 연속변수시스템과 대비해 이산사건시스템의 동적특성을 알아보고 구체적인 사례들을 살펴본다. 이러한 이산사건시스템의 동적특성을 기술하기 위해 형식언어이론에 기초한 논리적 이산사건모델을 소개하고 그 위에서 관리제어이론의 개념을 설명하나다 그리고 제어가능성 및 관측가능성의 관리제어기 존재조건을 토대로 관리제어기의 구현에 대해 알아본다 마지막으로 현재까지 수행되어온 관리제어에 대한 다방변의 연구 활동을 살펴보고 앞으로의 연구방향을 전만해 본다

• Journal of Korean Society of Transportation
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• v.29 no.4
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• pp.113-123
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• 2011

Traffic signal control is one of the most cost-effective means of improving urban mobility. With the recent progress of ITS (Intelligent Transportation System) and the installation of the real time traffic control systems, traffic signal control is conducted in online and real time. Normally, time-of-day (TOD) signal control is used with the system, but no definite methodology has yet been available for efficient TOD signal planing designing. Such method and process are in need to optimize the traffic signal timing plan. This paper proposes the optimization of TOD signal timings on arterials. The effects of the signal timings from the proposed method were assessed in the field. The proposed includes the methods determining the separation of the TOD break points and the TOD intervals. Those were tested on an arterial consisting of ten coordinated signalized intersections. It was found from the test results that the proposed TOD signal timing plans outperformed the previous signal timings.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.2015-2025
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• 1991

A long and light-weight forearm of the vertical 2 DOF robot manipulator with a heavy payload driven by parallel drive mechanism is modelled as a Euler-Bernoulli beam with a tip mass subjected to a high speed rotation. Governing equation is obtained by Hamilton's principle and represented as state variable form using the perturbed variables which describe the perturbed errors at the manipulator's final configuration. Digitial optimal control and observer theory are used to suppress the forearm vibration and control the positions of the joint angles with measured/estimated state feedback. Computer simulations and experimental results are obtained and compared each other.