• Ocean Systems Engineering
• /
• v.2 no.1
• /
• pp.49-68
• /
• 2012

In this paper, an offshore process front end engineering design (FEED) method is systematically introduced and reviewed to enable efficient offshore oil and gas production plant engineering. An integrated process engineering environment is also presented for the topside systems of a liquefied natural gas floating production, storage, and offloading (LNG FPSO) unit, based on the concepts and procedures for the process FEED of general offshore production plants. Various activities of the general process FEED scheme are first summarized, and then the offshore process FEED method, which is applicable to all types of offshore oil and gas production plants, is presented. The integrated process engineering environment is presented according to the aforementioned FEED method. Finally, the offshore process FEED method is applied to the topside systems of an LNG FPSO in order to verify the validity and applicability of the FEED method.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2000.04a
• /
• pp.7-12
• /
• 2000

As the offshore oil fields are moved to the deep ocean, the oil production systems of FPSO(Floating production storage and offloading system) are building these days and so it is the most important to estimate the drift motion and damping effects the drift motion importantly. The components of damping consist of viscous, wave radiation effect and wave drift damping. It is need to estimate the wave drift damping exactly among them. The wave drift damping means the change rate of mean wave drift force with respect to the ship and ocean structures speed. In order to calculate this, the 3-Dimensional panel method used to translating and pulsating Green function is adopted. The calculation is carried out for series 60(CB = 0.7) vessel and the results are compared with other theoretical ones.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.11b
• /
• pp.73-76
• /
• 2005

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. FPSO vessel dose not have self-propulsion system, but has additional facilities for oil production and positioning system. Main noise sources such as gas turbines, compressors, and pumps, are located on top of the hull (Topside area). 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 noise characteristics and the countermeasures for FPSO Topside area through investigation of noise analysis and site measurement results. Proper countermeasures, considering the characteristics of sources and receiver spaces, were applied from the noise prediction and various measurement results. Finally, this ship was successfully delivered with excellent noise properties.

• Ocean Systems Engineering
• /
• v.7 no.1
• /
• pp.53-74
• /
• 2017

Ship shaped FPSO (Floating Production, Storage and Offloading) units are the most commonly used floating production units to extract hydrocarbons from reservoirs under the seabed. These structures are usually much larger than general cargo ships and have their natural frequency outside the wave frequency range. This results in the response to first order wave forces acting on the hull to be negligible. However, second order difference frequency forces start to significantly impact the motions of the structure. When the difference frequency between wave components matches the roll natural frequency, the structure experiences a significant roll motion which is also termed as second order roll. This paper describes the theory and numerical implementation behind the calculation of second order forces and motions of any general floating structure subjected to waves. The numerical implementation is validated in zero speed case against the commercial code OrcaFlex. The paper also describes in detail the popular approximations used to simplify the computation of second order forces and provides a discussion on the limitations of each approximation.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2012.06a
• /
• pp.43-46
• /
• 2012

2011년 IMA의 자료[1]에 의하면, 현재 251척의 부유식 생산설비가 운영되고 있으며, 이중 FPSO가 차지하는 비율은 64%에 이른다. 또한, 가장 각광을 받고 있는 부유식 생산설비의 유형인 FPSO는 현재 40여척을 건조 (New building) 및 개조(Conversion)를 하고 있다. 전체적인 FPSO의 개발 및 건조 프로젝트는 일반 선박 프로 젝트와는 다르게 환경적, 정치적, 상업적인 영향을 많이 받는다. 예를 들면, 같은 구역에 석유/가스 채굴을 위한 프로젝트를 승인받은 기업들은 각자의 기술력, 재정상태, 채굴구역의 정치적인 영향력에 따라서 프로젝트의 초기 개념설계부터 전혀 다른 방향으로 구축할 수 있다. 이러한 변수가 많은 프로젝트를 성공적으로 수행하기 위해서는 각 단계별 세부 계획도 동시에 이루어져야 한다. 본 연구에서는 이러한 세계적인 해양구조물의 대표 격인 FPSO의 특성을 보고하고 이와 관련되는 프로젝트의 다양한 수행 절차 및 시스템/장비에 대해 설명한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2016.10a
• /
• pp.179-180
• /
• 2016

최근까지 모바일 디바이스와 고성능 클라우드 서버는 동일한 DVM 실행시간 환경에서 오프로딩을 통해 모바일 디바이스의 어플리케이션에 대해 실행속도 개선하려는 연구가 진행되고 있다. 본 논문에서는 안드로이드 실행시간 환경이 네이티브 어플리케이션을 지원하는 ART로 완전하게 전환되는 상황에서 DVM에서 실행되고 있는 모바일 레거시 어플리케이션에 대해 모바일 디바이스의 복잡한 계산 부담을 줄여 실행속도를 향상시고, 이를 통해 배터리 소모를 감소시키는 프로세스 단위 오프로딩 프레임워크에 대한 설계 내용을 제시한다.

• Journal of Ocean Engineering and Technology
• /
• v.14 no.4
• /
• pp.17-22
• /
• 2000

As the offshore oil fields are moved to the deep ocean, the oil production system of FPSO(Floating Production Storage and Offloading System) Type are constructed frequently these days. So, it is very important to estimate the drift motion and damping effects due to the drift motion simultaneously. The components of slow drift motion damping consist of viscous, wave radiation effect and wave drift damping. It is needed to estimate the wave drift damping more accurately than others. The wave drift damping signifies the time-rate of mean wave drift force on oscillating ship or ocean structure which constant speed. In order to calculate this, the 3-Dimensional panel method is employed with the translating and pulsating Green function in the frequency domain. The calculation is carried out for a Series 60 ($C_B$/=0.7) and the results are compared with other numerical ones.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.423-425
• /
• 2013

스마트 폰, 태블릿 PC와 같은 이동단말기기와 다양한 무선통신 기술의 발전으로 차세대 이동통신망은 다양한 액세스 네트워크들이 공존한다. 다양한 네트워크에서의 서비스 연속성 및 네트워크 상황에 따른 서비스 품질 저하, 그리고 EPC 망의 트래픽 과부하 현상은 여전히 문제로 남아있다. 본 논문에서는 EPC 망에서 측정된 QoS 정보에 따라 트래픽 경로 선택 기법을 제안한다. 제안한 방안을 통해 효율적인 네트워크 활용 방안과 최상의 핸드오버 방안을 제공할 수 있으며 사용자에게는 네트워크 상황에 따른 최적의 서비스를 제공할 수 있다.

• ETRI Journal
• /
• v.40 no.1
• /
• pp.61-71
• /
• 2018

In this study, we developed hybrid control algorithms in smart base stations (SBSs) along with devised communication, caching, and computing techniques. In the proposed scheme, SBSs are equipped with computing power and data storage to collectively offload the computation from mobile user equipment and to cache the data from clouds. To combine in a refined manner the communication, caching, and computing algorithms, game theory is adopted to characterize competitive and cooperative interactions. The main contribution of our proposed scheme is to illuminate the ultimate synergy behind a fully integrated approach, while providing excellent adaptability and flexibility to satisfy the different performance requirements. Simulation results demonstrate that the proposed approach can outperform existing schemes by approximately 5% to 15% in terms of bandwidth utilization, access delay, and system throughput.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2014.04a
• /
• pp.233-236
• /
• 2014

스마트폰의 보편화와 함께 스마트폰 응용프로그램의 요구성능이 점점 더 높아 지고 있다. 이를 충족시키기 위해서 사용자들은 스마트폰 교체 시기가 점점 더 짧아지지만, 체감 베터리 성능은 좀처럼 나아지기 힘들다. 이러한 문제를 해결하기 위해 모바일 오프로딩 기술이 개발되고 있지만, 모바일 오프로딩 기술은 응용프로그램의 성능을 하락시킬 수도 있는 양날의 검이다. 따라서 항상 최적의 오프로딩 성능을 얻기 위해서는 정확하고 효율적인 응용프로그램 성능 예측 기술의 적용이 우선시 되어야한다.