• Journal of Information Processing Systems
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• 제10권3호
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• pp.412-428
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• 2014

Request oriented sensor networks have stricter requirements than conventional event-driven or periodic report models. Therefore, in this paper we propose a minimum energy data aggregation (MEDA), which meets the requirements for request oriented sensor networks by exploiting a low power real-time scheduler, on-demand time synchronization, variable response frame structure, and adaptive retransmission. In addition we introduce a test bed consisting of a number of MEDA prototypes, which support near real-time bidirectional sensor networks. The experimental results also demonstrate that the MEDA guarantees deterministic aggregation time, enables minimum energy operation, and provides a reliable data aggregation service.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2516-2520
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• 2005

In this paper, finite impulse response (FIR) smoothers are proposed for discrete-time systems. The proposed FIR smoother is designed under the constraints of linearity, unbiasedness, FIR structure, and independence of the initial state information. It is also obtained by directly minimizing the performance criterion with unbiased constraints. The approach to the MVF smoother proposed in this paper is logical and systematic, while existing results have heuristic assumption, such as infinite covariance of the initial state. Additionally, the proposed MVF smoother is based on the general system model that may have the singular system matrix and has both system and measurement noises. Thorough simulation studies, it is shown that the proposed MVF smoother is more robust against modeling uncertainties numerical errors than fixed-lag Kalman smoother which is infinite impulse response (IIR) type estimator.

• 한국정보전자통신기술학회논문지
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• 제6권4호
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• pp.262-266
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• 2013

직교 주파수 분할 다중 (OFDM) 시스템에서는 채널의 지연확산 특성의해 발생하는 심볼간의 간섭 (ISI)을 제거하기 위해, 채널의 길이보다 길거나 같은 cyclic prefix (CP)를 삽입한다. 그러나 긴 CP는 전송률을 감소시 킨다는 단점이 있다. 대안으로, CP로 인한 성능 열화를 줄이기 위해 수신부에서는 channel shortening 필터를 이용하여 유효 채널의 길이를 줄이는 방법이 제안되어 왔다. 본 논문에서는 기존에 제안 된 채널 shortening 기 법인 minimum shortened signal to noise ratio (MSSNR), mimimum interblock interference (min-IBI)와 minimum intersymbol interference (min-ISI)을 비교분석한다.

• 제어로봇시스템학회논문지
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• 제13권10호
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• pp.990-999
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• 2007

We deal with second order NMP(Non-Minimum Phase) systems which are difficult to control with conventional methods because of their inherent characteristics of undershoot. In such systems, reducing the undesirable undershoot phenomenon makes the response time of the systems much longer. Moreover, it is impossible to control the magnitude of undershoot in a direct way and to predict the response time. In this paper, we propose a novel two sliding mode control scheme which is capable of determining the magnitude of undershoot and thus the response time of NMP systems a priori. To do this, we introduce two sliding lines which are in charge of control in turn. One is used to stabilize the system and achieve asymptotic regulation eventually like the conventional sliding mode methods and the other to stably control the magnitude of undershoot from the beginning of control until the state meets the first sliding line. This control scheme will be proved to have an asymptotic regulation property. The computer simulation shows that the proposed control scheme is very effective and suitable for controlling the second order NMP system because it can decide the magnitude of undershoot in a direct and stable way and reduce the response time compared with the conventional ones.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.174-176
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• 2000

In this paper, a high speed distance relay, using a digital signal processor(DSP) is presented. The idea of the protective algorithm is based on the least square method using minimum data window to minimize the relay operating time. A new disign concept for a low-pass filter is proposed. This analog low pass filter has minimum transient response time. The main processor of the relay is TMS320C31. According to a series of real time tests, the proposed protective relay shows reliable and fast operating characteristics.

• ETRI Journal
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• 제13권2호
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• pp.28-33
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• 1991

HiPi-Bus 는 여러가지 전송형태를 지원하며 이들은 데이터 전송의 관점에서 읽기 전송과 쓰기 전송으로 구분할 수 있다. 본 논문에서는 이들 읽기 전송과 쓰기 전송에 소요되는 시간을 최소화하는 방법을 제안하였는데, 이때 쓰기 전송에 소요되는 시간은 400n sec 이며, 읽기 전송에 소요되는 시간은 최소 400n sec 이다.

• 한국통신학회논문지
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• 제26권12A호
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• pp.1978-1982
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• 2001

다중 반송파 전송시스템에서 수신신호의 지연 확산에 따른 인접 심볼간섭 (ISI)과 인접 채널간섭 (ICI)을 제거하기 위하여 전송프레임에 삽입한 Cyclic Prefix (CP)는 시스템의 전송 효율을 저하한다. 시간영역 등화기는 채널 임펄스 응답 시간을 줄임으로써, 채널의 상태에 상관없이 CP 길이를 최소로 유지하여 시스템의 전송 효율을 개선한다. 본 논문에서는 MMSE (Minimum Mean Square Error) 방식 시간영역 등화기에 Newton 방법을 적용함으로써, 최적의 등화기 탭 계수를 추정하는 연산 시간을 단축할 수 있는 알고리즘을 제안하고 그 성능을 분석하였다.

• 지역연구
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• 제13권2호
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• pp.45-54
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• 1997

A regional economy is characterized as a spatial economy. However the literature shows that it has been treated as a point economy since space is little recognized in regional modeling due to mathematical complication. This leads to the fact that regional model does not sufficiently represent regional characteristic. This paper attempts to construct a regional growth model in a partial equilibrium framework specifically taking into consideration land as a primary factor. The model is formulated largely neoclassical. Labor is assumed to move in response to differences in the wage rate, while capital is perfectly mobile across regions. The paper shows that two growth equilibrium points exist, one stable equilibrium point and the other unstable equilibrium point. The unstable growth equilibrium indicates the existence of minimum threshold that a region must overcome the minimum threshold to grow constantly. Consequently, directions of regional growth are characterized by two growth paths depending on the initial condition of a region. That is to say, a region below the minimum threshold is converging toward the lower stable equilibrium point over time. When a regional economy initially lies above the minimum threshold, it will grow forever. A regional economy is not thus necessarily converging a stationary is not thus necessarily converging a stationary equilibrium point through factor movement. Finally, the impacts of the presence of agglomeration economies and diseconomies are analyzed through the phase diagram. The paper also shows that agglomeration economies result in lowering the minimum threshold and in escalating the level of stable equilibrium However, when agglomeration diseconomies prevail, the results are opposite, i.e., rising the minimum threshold of growth and lowering the growth level of stable equilibrium.

• 조명전기설비학회논문지
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• 제30권3호
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• pp.9-20
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• 2016

This study compared the effect of green light consequent on maximum brightness 85 lx and intial brightness 15 lx, and its accompanying psychological, physiological response. 1) As a result of psychology(general stress evaluation, Symptom Checklist-90-Revision) evaluation, all stress evaluation items mostly showed a decrease, and they are comparatively positively evaluated in minimum brightness 15 lx comparing to maximum brightness 85 lx. 2) Physiological (Heart Rate Variability) evaluation result was included in stable range in all cardiovascular system variables after light stimulus in time of comparison with the standard range; in addition, the Heart Rate Variability evaluation result was found to be stable in all cardiovascular system variables except Low Frequency in minimum brightness 15 lx comparing to maximum brightness 85 lx. 3) Green light was found not to appear as a stimulating factor in the human body in time of space projection, being found to be effective in stability of mind and body, and reduction in stress. Thus, it was found that green light functioned as an emotional, relaxing tranquilizer by working on the sympathetic nervous system.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.1125-1131
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• 2014

Application of residential demand response (DR) programs are currently realized up to a limited extent due to customers' difficulty in manually responding to the time-differentiated prices. As a solution, this paper proposes an automatic home load management (HLM) framework to achieve the household minimum payment as well as meet the operational constraints to provide customer's comfort. The projected HLM method controls on/off statuses of responsive appliances and the charging/discharging periods of plug-in hybrid electric vehicle (PHEV) and battery storage at home. This paper also studies the impacts of different time-varying tariffs, i.e., time of use (TOU), real time pricing (RTP), and inclining block rate (IBR), on the home load management (HLM). The study is effectuated in a smart home with electrical appliances, a PHEV, and a storage system. The simulation results are presented to demonstrate the effectiveness of the proposed HLM program. Peak of household load demand along with the customer payment costs are reported as the consequence of applying different pricings models in HLM.