• Journal of the Korea Society for Simulation
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• v.16 no.4
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• pp.43-55
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• 2007

Moving average(MA) and exponentially weighted moving average(EWMA) are the two most popular control methods in manufacturing. Both methods are optimized under the assumption that the exact control equation is known. This paper focuses on the problems rising from estimation errors. Based on the accuracy of the estimated parameter and the range of the weight parameter $\lambda$, the limitations are identified and the performance of methods are evaluated. Optimal adjustment for process shift with misestimated control model and its application control methods to actual process is researched. The efficiency of proposed method is evaluated through simulation.

• Journal of KIISE:Databases
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• v.36 no.4
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• pp.327-340
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• 2009

To achieve the noise reduction effect in boundary image matching, we use the moving average transform of time-series matching. Our motivation is based on an intuition that using the moving average transform we may exploit the noise reduction effect in boundary image matching as in time-series matching. To confirm this simple intuition, we first propose $\kappa$-order image matching, which applies the moving average transform to boundary image matching. A boundary image can be represented as a sequence in the time-series domain, and our $\kappa$-order image matching identifies similar images in this time-series domain by comparing the $\kappa$-moving average transformed sequences. Next, we propose an index-based matching method that efficiently performs $\kappa$-order image matching on a large volume of image databases, and formally prove the correctness of the index-based method. Moreover, we formally analyze the relationship between an order $\kappa$ and its matching result, and present a systematic way of controlling the noise reduction effect by changing the order $\kappa$. Experimental results show that our $\kappa$-order image matching exploits the noise reduction effect, and our index-based matching method outperforms the sequential scan by one or two orders of magnitude.

• Journal of KIISE:Software and Applications
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• v.27 no.9
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• pp.952-960
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• 2000

본 논문에서는 퍼지 자동회귀 이동평균 (Fuzzy Auto-Regressive Moving Average, FARMA)제어기를 전력계통의 비선형 2기 5모선 (Two Machine - Five Bus)모형의 주파수 안정화에 적용한 결과를 제시한다 퍼지 자동회귀 이동 평균 제어기는 기존의 전문가에 의존하였던 퍼지제어 규칙을 실시간으로 형성해 나가는 구조이다. 복잡성, 비선형성 등 전력계통의 일반적인 특징들을 기술하고, 그 특징을 표현할 수 있는 비선형 2기5모선 모형을 제시한다. 제시된 모형을 바탕으로 기존 제어 방식과의 성능 비교를 실시하였고, 이를 통하여 FARMA 제어기의 우수성을 확인하였다.

• Journal of KIISE:Information Networking
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• v.27 no.1
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• pp.39-47
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• 2000

This paper is to propose an efficient and reliable control procedure of Base Station Controller of mobile communication system for bulk input messages which was delivered instantaneously. We divided the input messages that are processed by the base station controller of the mobile communication system into two things ; they are messages related to call connection and o&m(operation and maintenance). In addition, we analyzed the properties of the input messages and then performed computer simulation on each input message by using M/M/1/K queueing model in term of the following viewpoints : the loss probability of input messages, the average queue length, the utilization of process controller(server),the average waiting time in queue. And we compared the performance of the two input messages in the overload controlling which was caused by the congested input messages.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.2
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• pp.47-55
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• 2012

A discrete-time(DT) filter with high-order temporal moving average(TMA) using actively-weighted charge sampling is proposed in this paper. To obtain different weight of sampled charge, the variable transconductance OTA is used prior to charge sampler, and the ratio of charge can be effectively weighted by switching the control transistors in the OTA. As a result, high-order TMA operation can be possible by actively-weighted charge sampling. In addition, the transconductance generated by the OTA is relatively accurate and stable by using the size ratio of the control transistors. The high-order TMA filter has small size, increased voltage gain, and low parasitic effects due to the small amount of switches and sampling capacitors. It is implemented in the TSMC $0.18-{\mu}m$ CMOS process by TMA-$2^2$. The simulated voltage gain is about 16.7 dB, and P1dB and IIP3 are -32.5 dBm and -23.7 dBm, respectively. DC current consumption is about 9.7 mA.

• Journal of KIISE
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• v.42 no.6
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• pp.769-780
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• 2015

Smoothing a digital curve by averaging its connected points is widely employed to minimize sharp changes of the curve that are generally introduced by noise. An appropriate degree of smoothing is critical since the area or features of the original shape can be distorted at a higher degree while the noise is insufficiently removed at a lower degree. In this paper, we provide a mathematical relationship between the parameters, such as the number of iterations, average distance between neighboring points, weighting factors for averaging and the moving distance of the point on the curve after smoothing. Based on these findings, we propose to control the smoothed curve such that its deviation is bounded particular error level as well as to significantly expedite smoothing for a pixel-based digital curve.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.10A
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• pp.1645-1652
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• 2001

제3세대 이동 통신 시스템에서 상향 링크와 하향 링크 사이에 불균형적인 타임 슬롯 할당이 가능한 TD/CDMA TDD 시스템은 비대칭적인 트래픽을 효과적으로 분배하는데 적합하다. 게다가 TD/CDMA TDD 시스템은 슬롯이 시간 영역과 코드 영역에서 정의되기 때문에 유효 자원의 statistical multiplexing이 매우 효과적이다. 그러나 상향 링크와 하향 링크사이의 트래픽의 비대칭성을 반영하기 위해서 타임 슬롯을 최적으로 할당시킬 수 있는 동적 경계선이 요구된다. 본 논문에서 슬롯의 하향 링크부분이 이동국의 접근 시도의 정도에 따라 최대화되는 새로운 최적의 TDD 경계선 제어 움직임 알고리즘을 제안하였다. 제안된 알고리즘에서 이동국의 평균 접근 시도가 미리 정의된 상한 임계치를 초과할 경우, TDD 경계선은 평균 접근 시도가 다른 하한 임계치 아래로 내려갈 때까지 프레임의 중앙에 위치한다. 본 논문에서 모의실험 결과를 통하여 제안된 알고리즘이 기존의 TDD 경계선 알고리즘보다 데이터 트래픽의 평균 접근 지연과 음성 트래픽의 블록킹 확률 측면에서 훨씬 더 좋은 성능을 나타냄을 입증하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.24-26
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• 2012

데이터 저장장치로 널리 사용되고 있는 플래시 메모리의 블록들은 소거 횟수가 제한되어 있어서 특정 블록에 소거 동작이 집중되지 않도록 마모 균등화 기능을 제공해야 한다. 저장 장치의 데이터들은 주기적으로 갱신이 자주 되는 hot데이터와 갱신이 거의 일어나지 않는 cold 데이터로 구성된다. 이런 두 가지 타입의 데이터로 인해 발생하는 소거 횟수에 대한 편차를 줄이기 위하여 정적 마모 균등화 기법을 사용하는데 데이터 이동에 따른 추가적인 소거 동작이 발생하게 된다. 본 논문에서는 데이터 이동 결정을 위한 임계값을 제어하여 플래시 메모리 내의 전체 블록들의 평균 소거 횟수가 크지 않을 때는 마모 균등화 작업을 자주 발생하지 않게 하고, 평균 소거 횟수가 소거 허용 한계치에 점차 근접하면 설정된 임계값으로 동작하도록 하여 정적 마모 평준화에 의해 추가되는 소거 횟수를 효율적으로 감소시키는 방법을 제안한다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.4
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• pp.104-111
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• 2012

It is advantageous to avoid the handover to cell whose dwell time is short or can be ignored in terms of service continuity and average throughput. This paper proposes the handover scheme that is suitable for vehicle in order to improve the wireless Internet service quality. In the proposed scheme, the handover process continues to be learned before being modeled to Discrete-Time Markov Chain (DTMC). This modeling reduces the handover frequency by preventing the handover to cell that could provide service sufficiently to passenger even when vehicle passed through the cell but there was no need to perform handover. In order to verify the proposed scheme, we observed the average number of handovers, the average RSSI and the average throughput on various moving paths that vehicle moved in the given urban environment.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.562-570
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• 2011

In this paper, a distributed mobile relay power control (DMRPC) scheme for maximizing individual cell throughput is proposed for mobile relay aided multi-cell orthogonal frequency division multiplexing (OFDM)-time division duplex (TDD) system. In the system with DMRPC, the power levels of relay's are controlled by individual cell without cell cooperation and signalling overhead. It is demonstrated by numerical simulation that DMRPC provides the better cell throughput performance than either the full power relay aided system or conventional system without relay does. Moreover, it is also shown that relay aided systems with DMRPC, and the conventional system have almost identical cell edge throughput, while full power relay aided systems show worse performance in cell edge throughput.