• Journal of Fisheries and Marine Sciences Education
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• v.22 no.2
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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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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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.

• Fire Science and Engineering
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• v.30 no.4
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• pp.6-13
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• 2016

With regard to smoke control system, the design guidelines of smoke exhaust for accommodation and smoke control for evacuation stairs and vestibule has been proposed domestically, but after reviewing the applicability to modern buildings that tend to be larger, higher and complex, a smoke control system according to domestic design guidelines might have difficulty in securing the safety from smoke in a fire. Therefore, it is necessary to adopt the performance-based design of a smoke control system that can enhance the safety and integrate the smoke control functions and design depending on the characteristics of fire and building structure in the case of fire in a large, high-rise, and complex building. This study analyzed the domestic design guidelines of a smoke control system and this paper proposes the part requiring improvement, and examines the legal system and guidelines on performance-based design of smoke control system in foreign countries.

• Journal of information and communication convergence engineering
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• v.14 no.3
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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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• v.9 no.5
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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.

• Journal of the Korea Society of Computer and Information
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• v.21 no.1
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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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• v.18 no.3
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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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.10
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• pp.877-888
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• 2012

Network virtualization technology is a crucial research issue of Future Internet which pursues a service-oriented architecture so-called NaaS (Network as a Service) or SDN (Software Defined Network). Network virtualization is expected to play an important role in Future Internet researches as a network testbed technology which enables innovative protocols to be experimented independently on a common testbed environment. We propose a control framework in order to provide user defined topology and bandwidth services with network virtualization and to separate and manage multiple-user traffics in a small and medium scale - single domain research network. The proposed framework (VIMS; Virtual network Integrated control and Management System) supports testbed expansions without any changes of heterogeneous virtual network support equipments through accommodation of each equipment's control plane. The framework shows a feasibility through applied to KOREN and we describe the differences and further study directions for improvement the framework comparing with GENI control framework.

• Journal of Korean Clinical Health Science
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• v.5 no.3
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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.

• Special Issue of the Society of Naval Architects of Korea
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• 2011.09a
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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.