• ETRI Journal
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• 제24권6호
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• pp.465-468
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• 2002

Ethernet passive optical networks (PONs) are an emerging access network technology that provides a low-cost method of deploying optical access lines between a carrier's central office and a customer site. In this paper, we propose a new algorithm of dynamic bandwidth allocation for multimedia services over Ethernet PONs. To implement the suggested dynamic bandwidth allocation algorithm, we present control message formats that handle classified bandwidths in a multi-point control protocol of Ethernet PONs.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.97-100
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• 1997

Fieldbuses are used as the lowest level communication network for real-time communication in factory automation and process control systems. Data generated from field devices can be divided into three categories: sporadic real-time, periodic real-time and non real-time data. Since these data share one fieldbus network medium, it needs a method that allocate the limited bandwidth of fieldbus network to the sporadic real-time, periodic real-time and non real-time traffic. This paper introduces an implementation method of bandwidth allocation scheme introduced in [51 on PROFIBUS. Using the modified PROFIBUS FDL(Fieldbus Data Link layer), the bandwidth allocation scheme introduced in [51 is verified by the experiments.

• 한국항공우주학회지
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• 제36권7호
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• pp.651-657
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• 2008

본 논문에서는 저사양의 반작용 휠을 이용하여 토크 가용성을 높이는 두 가지 기법이 제안 하였다. 첫 번째는 기존의 의사역행렬을 이용한 토크 제어 분배 법칙 대신 가중치가변 의사역행렬과 모멘텀을 최소화하는 제어 분배 법칙을 제안하여 반작용 휠의 토크, 모멘텀 제한 조건 내의 해를 찾도록 했다. 두 번째는 휠의 장착각을 변경하여 토크가 많이 필요한 축의 토크 가용성 자체를 증가시키는 방법을 제안하였다. 제안된 법칙들은 위성체의 자세 천이에 적용되었으며, 시뮬레이션을 통하여 성능 향상과 실제 위성의 적용 가능성을 기술했다.

• 한국작물학회지
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• 제48권3호
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• pp.135-138
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• 2003

1993-98년 동안 농촌진흥청의 벼직파재배 연구현황과 연구자원 배분의 경제적 합리성에 관한 연구결과는 다음과 같다. 1. 벼직파기술분야별 연구는 과거에는 기초연구부문에 집중되었으나 최근에는 직접 농민들의 현장애로를 타개하기 위한 파종, 입모, 잡초방제, 물관리 등 기능적 문제점을 해결하기 위한 연구투자가 확대되었다. 2. 직파재배의 초기에는 파종과 품종육성 부문에 연구투자가 크게 이루어졌으나 최근에는 그 비중이 줄어들고 시비개선, 잡초 방제, 물관리 부문에 대한 연구자원 배분이 늘어나고 있다. 3. 토양관리와 입모에 관한 연구비중은 줄어들고 있어 농민들의 이 부문에 대한 현장 애로는 크게 감소된 것으로 나타났다. 4. 벼직파재배에 대한 연구의 경제적 성과와 연구자원 배분은 기술분야별 일치성이 커서 합리적인 연구자원 배분이 이루어지고 있다.

• 한국해양공학회지
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• 제32권1호
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• pp.68-75
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• 2018

This study deals with the heading angle and depth keeping control technique for an ROV with multiple horizontal and vertical thrusters by thrust allocation. The light work class ROV URI-L, which is under development at KRISO, is a redundant actuating system with multiple thrusters that are larger than the ROV's degree of freedom. In the redundant actuating system, there are several solutions for a specific ROV motion to be performed. Therefore, a thrust allocation algorithm that considers the entire propulsion system should be regarded as important. First, this paper describes the propulsion system of the ROV and introduces the thrust allocation method of each motion controller. In addition, the performance of the controller is examined using a heading angle and depth keeping control test in a stationary state.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권1호
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• pp.16-33
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• 2019

In this paper, a full-duplex NOMA relaying based underlay device-to-device (D2D) communication scheme is proposed, in which D2D transmitter assists cellular downlink transmission as a full-duplex relay. Specifically, D2D transmitter receives signals from base station and transmits the superposition signals to D2D receiver and cellular user in NOMA scheme simultaneously. Furthermore, we investigate the power allocation under the proposed scheme, aiming to maximize D2D link's achievable transmit rate under cellular link's transmit rate constraint and total power constraint. To tackle the power allocation problem, we first propose a power allocation method based on linear fractional programming. In addition, we derive closed-form expressions of the optimal transmit power for base station and D2D transmitter. Simulation results show that the performance of two solutions matches well and the proposed full-duplex NOMA relaying based underlay D2D communication scheme outperforms existing full-duplex relaying based D2D communication scheme.

• 제어로봇시스템학회논문지
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• 제16권5호
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• pp.510-516
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• 2010

In this paper, a dynamic GTS allocation method of wireless control networks is proposed for the use of factory automation using IEEE 802.15.4 MAC protocol. A superframe of IEEE 802.15.4 is applied to the transmission method of real-time periodic I/O data of wireless control systems within the limited time in factory environment. The method is proposed for efficient transmission of real-time periodic I/O traffic. The simulation results show the average network utilization and available I/O node numbers could be increased by the proposed method.

• 전기학회논문지
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• 제66권2호
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• pp.292-299
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• 2017

In this paper, multiple ESS(Energy Storage System) control strategy for microgrids is presented. Installation of ESS becomes mandatory when microgrids are used to supply high quality power to the loads. The one of main functions of the ESS is to maintain power balance. However ESS has limitation of its capacity and instantaneous injecting power. Power allocation method based on SOC(State Of Charge) of each ESS is proposed. P-Q control is employed as the basic control strategy for the distributed ESSs. By using the proposed method, the coefficients in the conventional P-Q control method are modified. The ESSs with higher SOC inject more active power, while those with lower SOC inject less, leading to more balanced SOC levels among the ESSs. The proposed method is demonstrated by simulation using PSCAD/EMTDC.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.1253-1254
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• 2012

• Journal of Communications and Networks
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• 제11권2호
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• pp.157-165
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• 2009

In this paper, we investigate a dynamic spectrum sharing problem for the centralized uplink cognitive radio networks using orthogonal frequency division multiple access. We formulate a large-scale joint rate and power allocation as an optimization problem under quality of service constraint for secondary users and interference constraint for primary users. We also suggest admission control to nd a feasible solution to the optimization problem. To implement the resource allocation on a large-scale, we introduce a notion of using the conservative factors $\alpha$ and $\beta$ depending on the outage and violation probabilities. Since estimating instantaneous channel gains is costly and requires high complexity, the proposed algorithm pursues a practical and implementation-friendly resource allocation. Simulation results demonstrate that the large-scale joint rate and power allocation incurs a slight loss in system throughput over the instantaneous one, but it achieves lower complexity with less sensitivity to variations in shadowing statistics.