• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2012년도 전력전자학술대회 논문집
• /
• pp.546-547
• /
• 2012

In the three-phase power system using the three-phase load, when any one-phase is open-phase, the unbalanced current flows and the single-phase power supplied by power supply produces over-current. As a result, the enormous damage and electrical fire can be given to the power system. In order to improve these problems, this paper is proposed a new control circuit topology for open-phase protection using semiconductor devices. Therefore, the proposed open-phase protection device (OPPD) enhances the sensing speed and precision, and has the advantage of simple fitting in the three-phase distribution panel in the field, as it manufactures into small size and light weight. As a result, the proposed OPPD minimizes the electrical fire from open-phase, and contributes for the stable driving of the power system.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.1846-1850
• /
• 2005

This paper presents a constrained-based routing (CBR) algorithm called, Dynamic Possible Path per Link (D-PPL) routing algorithm, for MultiProtocol Label Switching (MPLS) networks. In MPLS on-line routing, future traffics are unknown and network resource is limited. Therefore many routing algorithms such as Minimum Hop Algorithm (MHA), Widest Shortest Path (WSP), Dynamic Link Weight (DLW), Minimum Interference Routing Algorithm (MIRA), Profiled-Based Routing (PBR), Possible Path per Link (PPL) and Residual bandwidth integrated - Possible Path per Link (R-PPL) are proposed in order to improve network throughput and reduce rejection probability. MIRA is the first algorithm that introduces interference level avoidance between source-destination node pairs by integrating topology information or address of source-destination node pairs into the routing calculation. From its results, MIRA improves lower rejection probability performance. Nevertheless, MIRA suffer from its high routing complexity which could be considered as NP-Complete problem. In PBR, complexity of on-line routing is reduced comparing to those of MIRA, because link weights are off-line calculated by statistical profile of history traffics. However, because of dynamic of traffic nature, PBR maybe unsuitable for MPLS on-line routing. Also, both PPL and R-PPL routing algorithm we formerly proposed, are algorithms that achieve reduction of interference level among source-destination node pairs, rejection probability and routing complexity. Again, those previously proposed algorithms do not take into account the dynamic nature of traffic load. In fact, future traffics are unknown, but, amount of previous traffic over link can be measured. Therefore, this is the motivation of our proposed algorithm, the D-PPL. The D-PPL algorithm is improved based on the R-PPL routing algorithm by integrating traffic-per-link parameters. The parameters are periodically updated and are dynamically changed depended on current incoming traffic. The D-PPL tries to reserve residual bandwidth to service future request by avoid routing through those high traffic-per-link parameters. We have developed extensive MATLAB simulator to evaluate performance of the D-PPL. From simulation results, the D-PPL improves performance of MPLS on-line routing in terms of rejection probability and total throughput.

• 수산해양교육연구
• /
• 제28권6호
• /
• pp.1561-1572
• /
• 2016

The ability to handle materials from one location to another, whether during transit or at the worksite is vital to all segments of industry. To varying degrees, many personnel in numerous workplaces take part in materials handling. Consequently, some employees are injured. In fact, rigging & slinging is a dangerous work using a crane and sling equipment to carry a cargo and the mishandling of materials is the single largest cause of accidents and injuries in the workplace. The majority of accidents associated with cranes and other lifting appliances are caused by faulty slinging, overloading, unbalanced loads, etc. which result in the load falling or tipping out of control, causing injury to people, damage to plant, machinery and the load. Therefore, recognizing the dangers of the works, there are much technical support including skill training in various institutes to minimize accidents during works on land. Although rigging work at sea is much dangerous than on land work because it needs to take account of the movements of the ships and waves, etc. in addition to land based rigging hazards, it is insufficient in appropriate actions that can improve the safety of the workers at sea. Therefore, this study suggested a rigging and slinging course for seafarers to improve their safety at sea by researching hazards and risk of rigging works and related skill training conducted on land.

• 전력전자학회논문지
• /
• 제6권4호
• /
• pp.325-332
• /
• 2001

전징기관은 내이에 존재하며 유연한 동작과 몸의 자세 그리고 운동을 조절한다. 이 기관은 회진 가속도를 감지하는 세반고리관과 선형 가속을 감지하는 이석기관으로 구성된다. 이러한 기관의 생체 신호로부터 의사는 사람이 환자인지를 판단한다. 이 신호의 데이터를 얻기 위해서 회전의자 한쪽을 들어올려 최대 30도까지 기울인 상태에서, 회전제어하게 되는데, 이 경우 부하의 불균형으로 인한 불평형 부하를 제거하고, 생체신호의 측정을 위하여 robust제어가 요구된다. 본 연구에서는 자세조절기능에 대한 이석기관의 역할을 추구하기 위하여 탈수직축 회전자극기를 개발하였으며, 공간을 차지하고 다양한 시각패턴을 만들지 못하는 기존 시각자극시스템의 단점을 해결하기 위하여 HMD를 이용한 시각자극 시스템을 개발하였다. 더구나 노이즈에 취약한 아날로그 신호인 ENG신호의 전송문제를 해결하기 위하여 근거리 R/F 무선시스템으로 개발하였다. 이상의 제안된 시스템을 제작하고 실험한 결과를 보고하였다.

• 한국산업정보학회논문지
• /
• 제21권3호
• /
• pp.29-33
• /
• 2016

청정에너지 발전설비의 요구가 늘면서 태양광, 풍력, 연료 전지 등의 분산전원 개발이 급속도로 증가하고 있다. 반면에 이러한 증가로 인하여 배전시스템은 복잡해지고 있으며 무효전력으로 인한 역률 저감, 불평형 부하에 의한 불평형 전류 등의 문제점을 가지고 있다. 이러한 문제점들을 해결하기 위하여 본 논문에서는 태양광용 3상 4선 타입의 전력변환장치에 무효전력, 불평형 전류를 보상하는 알고리즘을 적용하였다. 제안한 태양광 전력변환장치는 기본 출력동작 뿐만 아니라 계통 전력 품질의 저해요소들에 대해서 보상이 가능하며 PSCAD/EMTDC를 이용한 시뮬레이션을 통하여 그 성능을 검증하였다.