• Title/Summary/Keyword: Safe

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Assessment of Safe Navigation Including the Effect of Ship-Ship Interaction in Restricted Waterways (제한수역에서 두선박간의 상호간섭력을 포함한 안전항해의 평가)

  • Lee, Chun-Ki
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2003.05a
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    • pp.5-10
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    • 2003
  • This paper is mainly concerned with the assessment of safe navigation between ships moving each other in restricted waterways. The manoeuvring simulation was conducted parametrically to propose an appropriate sage speed and distance, which is required to avoid sea accident under the different conditions, such as ship-velocity ratios, ship-length ratios, separation and stagger between ships. The manoeuvring characteristics based on this investigation will be very useful for keeping the safety of navigation from the practical point of ships design and traffic control in confined water.

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The assessment of Safe Navigation Regarding Hydrodynamic forces between ships in Restricted Waterways

  • Lee, Chun-Ki;Yoon, Jeom-Dong
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.89-93
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    • 2006
  • This paper is primarily focused on the safe navigation between overtaking and overtaken vessels in restricted waterways under the external forces, such as wind and current. The maneuvering simulation between two ships was conducted to find an appropriate safe speed and distance, which is required to avoid collision. From the viewpoint of marine safety, a greater transverse distance between two ships is more needed for the smaller vessel. Regardless of external forces, the smaller vessel will get a greater effect of hydrodynamic forces than the bigger one. In the case of close navigation between ships under the forces of wind and current, the vessel moving at a lower speed is potentially hazardous because the rudder force of the lower speed vessel is not sufficient for steady-state course-keeping, compared to that of the higher speed vessel.

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A study on the Construction for the u-safe Korea System (유비쿼터스 기술 기반의 재난관리시스템 "u-safe Korea" 개발 구상)

  • Yi, Waon-Ho;Kim, Hyun-Ju;Park, Sang-Hyun;Jung, Tae-Ho
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.131-134
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    • 2008
  • Increasing the need of national safety management system in order to an epoch-making improvement to scientific disaster management which appears new types of disasters through the exchange of traditional disaster environment and responds actively to the rapid exchange of social environment based on u-IT. Requiring the development of systematical information sharing networking system and sharing realtime data amongst government, local authorities and related organisations under both safety management in normal times and circumstance management in disaster times, and need for the establishment of national safety strategy, which has been strengthened function such as prevention and preparation. This research provides a basic scheme and strategic tasks in order to constitute preventing scientific national disaster prevention structure at anytime and anywhere from disaster which is based on ubiquitous technology and realise the intelligent national disaster prevention system of u-safe Korea.

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Active Short Circuit Control Method to Reduce Overcurrent and Oscillation Current in PMSM (영구자석 동기모터 진동 및 과전류 저감을 위한 능동단락회로 제어 기법)

  • Choi, Jong-Won;Kim, Yoon-Jae
    • The Transactions of the Korean Institute of Power Electronics
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    • v.27 no.4
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    • pp.339-347
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    • 2022
  • This study proposes the mitigation method for overcurrent and oscillation motor current in an active short-circuit operation. This operation is attracting attention as the safe state of electric vehicle traction inverters. However, the active short-circuit operation generates oscillation and overcurrent of motor currents during a transient state. The proposed method uses two different safe states in PMSM, such as active short circuit and freewheeling. The active short circuit is used for safe state in a steady state. To reduce the overshoot and oscillation, a freewheeling state is injected between active short-circuit operation by comparing the motor phase current with an analytically calculated steady-state motor current. Freewheeling state is only used in a transient state. The performance is demonstrated through simulations and experimental results. The peak current of the motor was reduced from 52 A to 40 A, and oscillation time was reduced.

A Study on the Minimum Safe Distance Under the Low Speed Sailing of T.S. HANBADA (실습선 한바다호의 저속 항해시 최소안전 이격거리에 관한 연구)

  • Park Young-Soo;Ji Sang-Won;Lee Yun-Sok;Jung Chang-Hyun;Jeong Jin-A;Jung Min
    • Journal of Navigation and Port Research
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    • v.29 no.10 s.106
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    • pp.833-838
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    • 2005
  • This paper is to investigate the minimum safe distance between T/S Hanbada and a group of vessels participating in the event hosted by M broadcasting station who asked T/S Hanbada to keep a distance from $100m{\sim}500m$. The minimum safe distance was assessed by using ES Model which evaluates quantitatively the difficulty of shiphandling, and the simulation of marine traffic flow. As a result the minimum safe distance of T/S Hanbada moving at a speed of 2 knots turns out about 260m and is compared with the actual value.

Effects of Infection Control Strategies & Analysis of Risk Factors for Vancomycin Resistant Enterococci (신경외과 병동에 적용한 Vancomycin 내성 장구균의 감염관리 전략효과 및 균집락의 위험인자 분석)

  • Hong, Hae Kyung;Lee, Kkot Sil;Park, Sung Choon;Chung, Eun Kyung;Park, Mi Ra;Kim, Sae Chul
    • Quality Improvement in Health Care
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    • v.19 no.1
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    • pp.30-42
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    • 2013
  • Objectives: This study was intended to check if the "Creating Clean Wards" project, which is an innovative reinforced campaign activity targeting infection control strategies and active surveillance cultures for VRE (vancomycin resistant enterococci) high-risk patients to be admitted in the NS (neuro-surgery) wards, would be reduced the incidence rates of VRE acquisition, transmission rates. Methods: 75 subjects of the VRE high-risk patients were surveyed by carrying out active surveillance cultures of VRE colonization 11 times from January to March, 2012. And the retrospective study was conducted dividing them into two groups. Results: The incidence rates of VRE acquisition was reduced to 3.67 cases per 1,000 patients day in the control group and to 2.88 cases in experimental group, which was not statistically significant (p = .753). VRE transmission rates of 0.0015 per day before the project tended to increase to 0.0019, although not statistically significant (p = .650). As a result of multivariate analysis with regard to using glycopeptide antibiotics in order to find out risk factors of VRE colonization, the patients who had been treated with glycopeptide until VRE colonization showed 274.41 times higher rate. Conclusion : For effective VRE infection control in NS wards, We should carry out active surveillance culture regularly, especially patient of using glycopeptide. And block the spread of VRE by strengthening infection control through the strict isolation and the changed mind-set of members motivated by the "Creating Clean Wards" campaign.

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