• 인터넷정보학회논문지
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• 제15권5호
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• pp.1-7
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• 2014

무선센서 네트워크(WSNs)는 일반적으로 수많은 센서노드들이 배치되어 데이터를 전송하며, 불필요한 데이터 전송으로 인해 에너지 낭비를 초래한다. 기존의 연구들은 주로 에너지 소모문제를 해결하는데 집중되었다. 하지만 실시간으로 정보전송이 필요한 어플리케이션에 대해서는 지연 보장 역시 고려되어야 한다. 본 논문은 생체시스템을 모방하여 무선센서망에서 에너지의 소모와 연시간을 줄이기 위한 BISA(Bio-inspired Scheduling Algorithm)를 제안한다. BISA는 에너지 효율성이 높은 라우팅경로를 탐색하고 다중채널을 이용해 데이터 전송경로를 다중화함으로써 데이터 전송을 위한 에너지소모와 지연시간을 최소화한다. 실험결과를 통해 제안한 알고리즘의 기존방식 보다 적은 에너지를 사용하며 동시에 요구지연 시간을 보장함을 확인한다.

• Journal of Electrical Engineering and Technology
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• 제7권6호
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• pp.814-823
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• 2012

Electric power transmission utilities make an effort to maximize profit by reducing their electricity supply and operation costs while maintaining their reliability. The development of maintenance strategies for aged components is one of the more effective ways to achieve this goal. The reliability centered approach is a key method in providing optimal maintenance strategies. It considers the tradeoffs between the upfront maintenance costs and the potential costs incurred by reliability losses. This paper discusses the application of the Particle Swarm Optimization (PSO) technique used to find the optimal maintenance strategy for a transmission component in order to achieve the minimum total expected cost composed of Generation Cost (GC), Maintenance Cost (MC), Repair Cost (RC) and Outage Cost (OC). Three components of a transmission system are considered: overhead lines, underground cables and insulators are considered. In regards to aged and aging component, a component state model that uses a modified Markov chain is proposed. A simulation has been performed on an IEEE 9-bus system. The results from this simulation are quite encouraging, and then the proposed approach will be useful in practical maintenance scheduling.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(1)
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• pp.275-278
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• 2000

Recently ATM(Asynchronous Transfer Mode) technology is facing challenges from Integrated Service IP(Internet Protocol), IP router, Gigabit Ethernet. Although ATM is approved by ITU-T as the standard technology in B-ISDN, its survival is still in question. In the ATM networks, the Guaranteed Frame Rate(GFR) service has been designed to accommodate non-real-time applications, such as TCP(Transmission Control Protocol)/IP based traffic. The GFR service not only guarantees a minimum throughput at the frame level, but also supports a fairshare of available resources. We have studied different discarding and scheduling schemes, and compared their throughput and fairness when TCP/IP Traffic is carried. Through simulations, we know that only per-VC queueing with weighted Round Robin(WRR) can guarantee Minimum Cell Rate Among all the Schemes that have been experimented, we recommend DT-EPD(Dynamic Threshold-Early Packet Discard) integrated with MCRplus(Minimum Cell Rate) to support the GFR service.

• 대한전기학회논문지
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• 제35권12호
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• pp.594-602
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• 1986

This paper proposes an effective algorithm for short-term generation scheduling for the purpose of economic and secure operation of thermal power systems. Especially, in the procedure of solution by Dynamic Programming, Linear Programming is introduced to promote the possibility of optimal solution and the security of power systems, and evaluation of security function is improved by the application of seven step approximation of normal distribution. Several necessary considerations, that is, time dependent start-up and constant down cost of generating units, demand and spinning reserve constraints, minimum up and sown time constraints, the number of possible start-up of a generating unit in a d and the number of generating units which can be started up at the same time at the same bus, are also incoporated to elevate the usability and flexibility of the algorithm. Finally, the effectiveness of the proposed algorithm has been demonstrated by applying to the 6-gen. 21-bus model power system.

• 디지털산업정보학회논문지
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• 제5권2호
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• pp.101-107
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• 2009

In existing wireless ad-hoc networks, how to distribute network resources fairly between many users to optimize data transmission is an important research subject. However, in wireless mesh networks (WMNs), it is one of the research areas to avoid gateway bottleneck more than the fair network resource sharing. It is because WMN traffic are concentrated on the gateway connected to backhaul. To solve this problem, the paper proposes Weighted Fairness Time-sharing Access (WFTA). The proposed WFTA is a priority time scheduling scheme based on Weighted Fair Queuing (WFQ).

• 한국컴퓨터산업학회논문지
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• 제5권9호
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• pp.873-882
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• 2004

Multimedia database system can be improve data transferring efficiency by consulting catalogue database which is storing the object and serving multimedia meta-database and perform the pre-scheduling for data transferring and by delaying of transferring to reduce the responding timeand reordering the data by various method of transferring. By Introducing these techniques we can enhance the server resources utilizing, minimizing the users responding time and can decrease failure at the scheduling itself and easily search and transfer the information that the user wanted. Like this, the importance of multimedia information treating skill and efficient management are widely recognized and expected lots of research and development to form a butter efficient multimedia database syst

• 대한전기학회논문지:시스템및제어부문D
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• 제53권10호
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• pp.714-719
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• 2004

The Controller Area Network (CAN) is being widely used in real-time control applications such as automobiles, aircraft, and automated factories. Unfortunately, CAN, in its current form, is not able to either share out the system bandwidth among the different devices fairly or to grant an upper bound on the transmission times experienced by the nodes connected to the communication medium as it happens, for instance, in the token-based networks. In this paper. we present the message scheduling for CAN, based on the distributed control scheme to integrate actuators and sensors in a humanoid robot. Besides introducing the new algorism, this paper also presents some performance figures obtained using a specially developed software simulator, while the behavior of the new algorism is compared with the traditional CAN systems, in order to see how effective they are.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.269-270
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• 2008

TD-SCDMA combines TDMA and CDMA components to provide more efficient use of radio resources, and includes a new feature called HSDPA (high-speed downlink packet access) in the R5 stage. The TD-HSDPA supports high-speed traffic with a shared channel, but the adopted mechanism causes feedback problem for scheduling. In this paper, we propose an improved mechanism that transmits channel quality indicator (CQI) more frequently, so that the TD-HSDPA scheduler can utilize all possible information about the downlink channel status.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.271-272
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• 2008

TD-SCDMA combines TDMA and CDMA components to provide more efficient use of radio resources, and includes a new feature called HSDPA (high-speed downlink packet access) in the R5 stage. The TD-HSDPA supports high-speed traffic with a shared channel, but its uplink mechanism causes feedback problem for scheduling. Since the base station of TD-SCDMA can estimate the location of mobile terminals precisely, it can also estimate the possible path loss. In this paper, the base station utilizes the estimated path loss for scheduling, which is related with CQI (channel quality indicator) values. The proposed mechanism can provide the TD-HSDPA scheduler with an intial CQI value for efficient transmission.

• 반도체디스플레이기술학회지
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• 제12권4호
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• pp.1-7
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• 2013

This paper presents the AMR (Automatic Meter Reading) system using the binary CDMA (Code Division Multiple Access) radio technology. The binary CDMA is the new radio technology in domestic research. Main implementation topics includes the binary CDMA remote meter reading system, the wireless piconet configuration for the wireless automatic meter reading, and the transmission scheduling for sending and receiving data. Also, the wireless packet data encryption is very important topics for the wireless automatic meter reading. The proposed AMR system is implemented as a pilot project in Jeju and Gangwon. It can be seen that the wireless remote reading using the binary CDMA wireless technology can be applied to the AMR system.