• 수산해양교육연구
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• 제22권2호
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• pp.218-230
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• 2010

This study was conducted to determine the effect of the noise level on the boarding environment in a stern trawl ship, KAYA(GT: 1,737 tons, Pukyong National University). We measured the noise level at a working, an accommodation and a teaching area, and an engine space on January 9, 2010 while the KAYA was sailing on a liner sea route. At the working area, the ranges of the noise rating number(NRN) and the NRN determination frequency(FNRN) were from 44 to 73 and from 1000 to 2000Hz, respectively. The results were generally satisfied the criteria of the International Maritime Organization(IMO). The noise level at the area, except the radio room(w2), was exceeded the criteria(50dB(A)) for the efficient studying and working. The noise level at the engine control room and the machine workshop was respectively exceeded 1.2dB and 9.5dB than the criteria caused the conversation disturbance (70dB(A)). At the accommodation, NRN and FNRN were from 49 to 54 and from 1000 to 4000Hz, respectively. The noise level was below the criteria of IMO, but above 40dB(A) caused the sleep disturbance. At the teaching area, NRN and FNRN were from 44 to 63 and from 500 to 2000Hz, respectively. The noise level was exceeded than the criteria(50dB(A)) for the efficient studying. At the engine space, NRN and FNRN were from 95 to 100 and from 2000 to 4000Hz, respectively. The noise level was above the criteria of IMO(90dB(A)) for the residence, while it was not exceeded 110dB(A) for the transient.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.550-553
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• 2004

Recently, the demand for the Floating, Production, Storage, and Offloading facility (FPSO) which has some economic and technical advantages, has increased in offshore oil production areas. The 36,8000 DWT class FPSO was built in Hyundai Heavy Industries and will be installed in Offshore Angola. She dose not have self-propulsion system, but has additional facilities for oil production and positioning system. Main noise sources are contributing to the cabin noise of the accommodation are classified into three classes such as the machinery in the engine room and the deckhouse, HVAC system, and the topside equipments. In general, the noise regulation for the offshore structure is severer than that of the cargo ship and acceptable noise limit of cabin is specified as 45 dB(A). This paper describes the procedure of noise analysis, the countermeasures of noise control, and the measurement results of the quay trial. In order to minimize the noise levels, careful attention have to be paid by the special committee of experts from the initial design stage to the delivery. Proper countermeasures, considering the characteristics of sources and receiver spaces, were applied from the noise prediction and various experiment results. Finally, this ship was successfully delivered with excellent noise properties. The technology to minimize the noise levels for FPSO has been established throughout the construction of this ship.

• 한국화재소방학회논문지
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• 제30권4호
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• pp.6-13
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• 2016

건축물에서의 연기제어 시스템과 관련하여 국내에서는 거실에 대한 배연기준과 피난계단 및 부속실에 대한 제연기준이 제시되고 있으나, 대형화 고층화 복합화 되어가는 첨단 건축물에 대한 적용성을 검토하면 국내 설계기준에 따른 연기제어 시스템은 화재시 연기안전을 확보하기 곤란할 수 있다. 따라서 대형 고층 복합의 첨단 건축물에 대한 화재시 연기안전성을 높이고 화재와 건축물 특성에 따른 상호 연기제어 연계성 확보와 통합적 설계가 가능한 성능위주 연기제어의 적용이 요구된다. 본 논문에서는 국내 연기제어 기준을 분석하고 개선이 필요한 부분을 제시하였으며, 선진외국에서의 성능위주 설계 수행에 대한 법체계와 성능위주 연기제어 설계의 지침을 조사하고 분석하였다.

• Journal of information and communication convergence engineering
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• 제14권3호
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• pp.191-199
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• 2016

In this study, we investigate the safety requirements and test methods of a radiofrequency stimulator. The main test items include controls of a minimum output, accommodation range, and output parameters that have been known as the safety requirements in conformity with international standards. As the test criteria for controlling the minimum output, an increase or decrease in a unit of 1 mA or 1 V or less was applied to the output amplitude regulator for both continuous and discontinuous control, and the output at the minimum setting was manipulated to not exceed 2% of the maximum setting. For controlling the output parameters, one of the representative test criteria states that the current limit of 250 mA should be equal to or less than 1,500 Hz. Consequently, when applying the radiofrequency stimulator on the human body, we need to ensure that the safety requirements conform to the international standards.

• Journal of Power Electronics
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• 제9권5호
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• pp.791-799
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• 2009

This paper presents a time-varying sinusoidal disturbance compensation method (based on an adaptive estimation scheme) for induction motor drives fed by a matrix converter. In previous disturbance accommodation methods, sinusoidal disturbances with unknown time-invariant frequencies have been considered. However, in the new method proposed here, disturbances with unknown time-varying frequencies are considered. The disturbances can be estimated by using a disturbance accommodating observer, and an additional control input is added to the induction machine drive. The stability analysis is carried out considering the disturbance estimation error and simulation results are shown to illustrate the performance of the proposed solution.

• 한국컴퓨터정보학회논문지
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• 제21권1호
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• pp.49-57
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• 2016

In this paper we propose the resource allocation scheme for the overlaid macro-femtocell networks, which considers the type of handovers such as the inter-macrocell, macrocell-to-femtocell, femtocell-to-macrocell, or inter-femtocell in order to guarantee Quality of Service (QoS) and expand the accommodation capacity. Our proposed scheme takes into account the movement of mobile terminals, the QoS degradation, or the load control which trigger handovers in the overlaid networks, before it allocates resources dynamically. Moreover it considers QoS requirements of realtime or non-realtime mobile multimedia services such as video communication, Video on Demand (VoD) and dataa services. Simulation results show that our scheme provides better performances than the conventional one with respect to the outage probability, data transmission throughput and handover failure rate.

• International Journal of Aeronautical and Space Sciences
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• 제18권3호
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• pp.535-544
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• 2017

In-flight aircraft engine performance estimation is one of the key techniques for advanced intelligent engine control and in-flight fault detection, isolation and accommodation. This paper detailed the current performance degradation estimation methods, and an improved hybrid Kalman filter via velocity-based LPV (VLPV) framework for these needs is proposed in this paper. Composed of a nonlinear on-board model (NOBM) and VLPV, the filter shows a hybrid architecture. The outputs of NOBM are used for the baseline of the VLPV Kalman filter, while the system performance degradation factors on-line estimated by the measured real system output deviations are fed back to the NOBM for its updating. In addition, the setting of the process and measurement noise covariance matrices' values are also discussed. By applying it to a commercial turbofan engine, simulation results show the efficiency.

• 한국통신학회논문지
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• 제37B권10호
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• pp.877-888
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• 2012

네트워크 가상화 기술은 NaaS (Network as a Service) 또는 SDN (Software Defined Network)으로 불리는 서비스 지향 아키텍처를 추구하는 미래인터넷에서 중요하게 다루고 있는 연구 분야이다. 네트워크 가상화는 혁신적인 프로토콜들에 대한 상호 독립적인 시험이 가능한 네트워크 테스트베드 구축 기술로서 미래인터넷 연구에서 중요한 역할을 할 것으로 기대하고 있다. 본 논문에서는 단일 도메인의 중소규모 연구망에서 네트워크 가상화를 통해 사용자가 정의하는 토폴로지와 대역폭을 제공하여 다중 사용자의 서비스 트래픽들을 분리, 관리함을 목적으로 하는 제어프레임워크를 제안한다. 본 프레임워크(VIMS; Virtual network Integrated control and Management System)는 이기종의 가상네트워크 장비 제어평면을 수용함으로써 장비에 변경을 요하지 않고 확장할 수 있는 구조를 지닌다. KOREN (Korea advanced REsearch Network)에 적용, 실현 가능성을 확인하였으며 GENI의 제어프레임워크와 비교를 통해 본 프레임워크와의 차이점과 개선을 위한 향후 연구 방향을 도출한다.

• 한국임상보건과학회지
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• 제5권3호
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• pp.888-896
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• 2017

Purpose. The purpose of this study was to investigate the effect of visual field training on visual function, visual perception and attention enhancement. Methods. We examined the changes of visual function and visual perception tests for children with mild developmental disabilities through vision therapy. Results. At the time of the initial visit of the child, the ability to control not only distant and near visual function, but also accommodation, was also very limited. Also, the visual perception score was measured at 80 points. Through vision therapy, it was confirmed that the improvement of control ability as well as the visual function and visual perception function test results were also improved to 108 points. Conclusion. It was confirmed that vision therapy results in an improvement of visual function, improved visual perception ability, as well as visual perception ability, It was concluded that visual function affected visual perception, and that vision therapy used in order to prevent visual function deterioration was found to be very helpful.

• 대한조선학회 특별논문집
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• 대한조선학회 2011년도 특별논문집
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• pp.112-116
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• 2011

The noise analysis is usually carried out in the early structure design stage for the main areas in a vessel such as an accommodation, an engine room, HVAC System and etc. If the analysis results are higher than the noise limits based on guideline, appropriate countermeasures are established to reduce noise levels and applied to the vessel. But excessive noise induced the main or auxiliary equipment and high pressure steam system is very difficult to check in the initial design stage, and local noise problems frequently appear in actual vessels. This paper deals with excessive noise of the engine control room on LNG carrier. It includes the cause analysis of excessive noise, the countermeasure, and verification. Also, it proves suitability of the countermeasure through the on-board test.