• 대한조선학회논문집
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• 제44권4호
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• pp.379-388
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• 2007

Ever increasing fuel prices and environmental concerns are forcing commercial vessel operators and designers to re-assess current vessel designs with an emphasis on their propulsion systems. The most important parameter determining propulsive efficiency is the diameter of propeller. Many investigations have been carried out to adapt a large and slow turning propeller known as one of the most robust and effective way of achieving high efficiency in ship propulsion system. However, for the same vessel a further increase of propeller diameter would require the modification of the aft end while still paying attention to the hull clearance to prevent excessive propeller excited vibrations. In order to take the advantage of this approach small workboats (e.g. tug boats, fishing vessels etc.) operate in service with a significant increase of aft draught and hence resulting "inclined keel" configuration can be observed. Although it is not unusual to see large vessels sometimes to operate with stern trim to improve their operational performance and fuel efficiency, it is rare to see a such vessel purposely built with an inclined keel feature to fit a large diameter propeller for power saving. This paper investigates the application of the inclined keel configuration to a 3600TEU container vessel with the aim of fitting an 11 % larger diameter propeller (and hence resulting 17.5 % lower rpm) to gain further power saving over the similar size basis container ship with conventional "level keel" configuration.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2535-2541
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• 2009

Prebiotic isomaltooligosaccharide preparations contain $\alpha$-D-glucooligosaccharides comprising isomaltooligosaccharides (IMOs) and non-prebiotic maltooligosaccharides (MOs). They are both glucose oligosaccharides characterized by their degree of polymerization (DP) value (from 2 to $\sim$10), linkages types and positions (IMOs: $\alpha$-(1$\rightarrow$2, 3, 6 and in a lower proportion internal 1$\rightarrow$4) linkages, MOs: α-(1$\rightarrow$4) linkages). Their structure is the key factor for their prebiotic potential. In order to determine and elucidate the exact structure of unknown IMOs and MOs, unambiguous assignments of $^{13}C$ and $^1H$ chemical shifts of commercial standards, representative of IMOs and MOs diversity, have been determined using optimized standard one and two-dimensional experiments such as $^1H$ NMR, $^{13}C$ NMR, APT and ${^1}H-{^1}H$ COSY, TOCSY, NOESY and <$^1H-{^{13}}C$ heteronuclear HSQC, HSQC-TOCSY, and HMBC. Here we point out the differential effect of substitution by a glucose residue at different positions on chemical shifts of anomeric as well as ring carbons together with the effect of the reducing end configuration for low DP oligosaccharides and diasteroisotopic effect for H-6 protons. From this study, structural $^{13}C$ specific spectral features can be identified as tools for structural analysis of isomaltooligosaccharides.

• Journal of the Korean Data and Information Science Society
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• 제22권5호
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• pp.989-998
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• 2011

Cloud computing provides computation, software, data access, and storage services that do not require end-user knowledge of the physical location and configuration of the system that delivers the services. Cloud computing providers have setup several data centers at different geographical locations over the Internet in order to optimally serve needs of their customers around the world. One of the fundamental challenges in geographically distributed clouds is to provide efficient algorithms for supporting inter-cloud data management and dissemination. In this paper, we propose a group quorum system (GQS)-based dissemination for improving the interoperability of inter-cloud in time-critical event dissemination service, such as computing policy updating, message sharing, event notification and so forth. The proposed GQS-based method organizes these distributed clouds into a group quorum ring overlay to support a constant event dissemination latency. Our numerical results show that the GQS-based method improves the efficiency as compared with Chord-based and Plume methods.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.128.5-128
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• 2001

This paper presents investigation of an arc force sensor for a robotic welding control system. Arc force sensor is employed in this research to monitor the bead geometry of the arc welding process. Arc force sensor mounted at the end of the robot wrist was employed to measure the arc force applied to the weld. Experimental configuration for measurement of arc force was used to quantify the changes in the arc force distributions of the plate being welded. A relationship between the bead dimension and the arc force distributions was established. The sensor information was used to establish a relationship between welding current and arc force. Arc force sensor have shown to be one of the most sophisticated technique to monitor perturbations that occurred during robotic arc welding process.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.496-499
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• 2007

The COMS ground segment will operate the geostationary satellite continuously 24h/7days and deliver processed data to end-users with respect to the predefined schedule without delay. For reliable operation, each COMS ground center has internally dual-configuration for critical systems but impossible to every components. Any unexpected failure or regular maintenance to the single configured antenna system may lead the interruption of COMS service and operation. The natural disaster or external attack can destroy one ground center and the operation will be stopped. Therefore COMS program implements backup system remotely located in other centers. Even considering foreign geostationary systems, it's the best solution guaranteeing consistent system operation against internal failure or external disaster.

• 한국자동차공학회논문집
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• 제7권5호
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• pp.22-30
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• 1999

Optimization of in-cylinder flow is regarded as one of the most important factors to realize stable stratified charge combustion in a Spark-ignited Direct Injection(SDI) engine. Therefore, Computational Fluid Dynamic(CFD) simulation technique were used to clarify the characteristics of in-cylinder flow of a SDI engine with top entry intake port. Also, CFD results were compared to experimental results using Laser Doppler Velocimetry(LDV), Particle Image Velocimetry(PIV) and good validations were met. As the results reverse tumble flow generated during intake process was preserved by configuration of curved piston while base and reverse tumbles were diminished at the end of compression stroke in case of flat top piston. In addition, it will be needed to optimize the fuel mixture distribution based on these results.

• 한국농촌건축학회논문집
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• 제2권3호
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• pp.77-84
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• 2000

Kurye-gun, which Hwaeomsa temple is located, has huge scale's geographical characteristics, such as mountains, rivers and open fields. This is really blessing area because of Som-jin river at the bottom of Ghiri mountain and open fields, which this situation is very difficult. The location of Hwaeomsa temple is an end of The Baek-Doo Mountains and very important spot(where influences to its geometric converge) of the theory of feng-shui. On exposure logic of the Korean traditional theory of feng-shui, the organization in Ga-Ram of Hwaeomsa temple is inconsistent with representative theory and analyzing system. So, this is one of successful examples with the theory of feng-shui because exhalation from the earth and water was organized well with accuracy.

• Journal of Advanced Research in Ocean Engineering
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• 제4권4호
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• pp.163-173
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• 2018

There are many issues in fluid structure interactions when dealing with the free surface flows in a sloshing tank. For example the problem of how yielding a highly nonlinear wave with a simple forced motion over a short duration is of concern here. Nonlinear waves are generated in a rectangular tank which is forced horizontally; its motion consists of a single cycle of oscillation. One of the objectives is to end up with a shape of the free surface yielding a wide range of critical flows by tuning few parameters. The configuration that is studied here concerns a plunging breaker accompanied with a critical jet where great kinematics are simulated. The numerical simulations are performed with a twodimensional code which solves the fully nonlinear free surface boundary conditions in Potential Theory.

• 역사민속학
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• 제45호
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• pp.291-325
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• 2014

본 연구는 제천례의 변화양상을 고려, 조선 그리고 중국과의 의례비교를 통해 그 차이를 살펴보고자 하는 것이다. 고려와 조선의 제천례는 표면적으로는 비슷해 보이지만 내용상 의식의 차이가 존재하고 있다. 이러한 차이는 유교적 의례인 제천례가 중국의 영향을 받는다는 점을 고려하여 중국의 어떠한 시기의 영향을 받았는지를 살피고자 하는 것이다. 본 연구는 여말선초 제천례의 변천과정을 의례 분석을 통하여 검토하는 것이다. 이를 위해 중국 역대 예서와의 비교를 하였다. 이를 통해 중국 우리나라 제천례의 차이점 및 변화의 원인을 찾아내는 것이다. 또 실제로 시행된 제의를 분석하여 여말선초 제천례의 역사적 성격을 파악하고자 하였다. 연구 목적을 달성하기 위하여 다음과 같은 방법론적 접근을 하였다. 각종 연대기와 의례서를 통해 고려부터 세조대에 이르기까지의 제천례의 역사적 변천과정 및 기본 의식을 살펴보았다. 제천례 시행의 변화추세 파악은 동일한 제천례의 시행일지라도 당대의 시대상황에 따라 달리 표현된다. 기존의 연구는 여말선초 제천례에 대한 국내의 자료만을 주된 대상으로 하여 고찰하였다. 그러나 제천례의 정착과정은 유교적 의례의 정착과 밀접한 관련성을 가지고 있다. 제도적 변천은 국내의 자료만을 대상으로 하였을 경우 나타나는 문제들을 해결할 수 없다. 때문에 반드시 중국에서의 제천례의 변화모습과 관련하여 그 변화의 추이를 살펴보았다. 이를 통해 중국에서의 제천례가 우리나라에서는 어떠한 방식으로 정착되고 있는지, 또한 중국 역대 예서와의 비교를 통해 양자의 차이점 및 변화의 원인을 찾아내고, 아울러 실제로 시행된 제의를 분석하여 여말선초 제천례의 역사적 성격을 파악하였다. 여말선초와 중국 제의 절차는 고려와 조선이 비슷하지만 실제의 내용상 차이가 존재한다. 또 당나라와 송나라 그리고 명나라에서의 의례절차가 차이가 있음을 알 수 있다. 이러한 차이는 우리나라와도 직결되고 있으며, 황제권의 변화와도 관련을 가지고 있다고 생각된다. 대체로는 당과 송이 비슷한 경향을 보이고 있으며, 명나라가 이들 두 나라와 차이를 극명하게 보여준다. 예컨대, 절을 하는데 있어서의 차이, 초헌 아헌 종헌의 주관자 차이가 다르게 나타난다. 또 배위의 변화 등이 있다. 배위의 변화는 황제권의 위상과 관련하여 중요한 의미를 가진다. 제단의 크기, 신주, 분헌관, 옥폐(玉幣), 배위(配位), 종사(從祀) 등 구체적 분석은 막연하게 다른 모습을 이야기하는 것이 아니라 실제적인 차이들을 고찰하였다. 그리고 이러한 토대위에 국가간, 시대간 차별성을 규명할 수 있었고, 그러한 차이에 대한 의미를 부여하였다.

• 한국통신학회논문지
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• 제28권11B호
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• pp.1016-1022
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• 2003

EPON(Ethernet Passive Optical Network)은 FTTH(Fiber To The Home)구성에 경제적인 기술로서, 차세대 가입자망 구성중 하나로 활발히 연구되고 있다. EPON은 Ethernet을 기반으로 하고 있기 때문에 QoS(Quality of Service) 지원을 위해서는 가입자에게 동적 대역폭할당을 적용해야 한다. 최근 EPON 표준화에 대해 활발히 연구하고 있는 EFM SG 방향 역시 동적 대역폭할당으로 결정한바 있다. 따라서 본 논문에서는 EPON의 MAC(Media Access Control) 프로토콜인 MPCP(Multi Point Control Protocol)에서 DBA(Dynamic Bandwidth Allocation)의 구현에 적합한 ONU(Optical Network Unit) 버퍼 스케줄링 알고리즘(AIWFQ)과 OLT(Optical Line Terminal)의 DBA 전략(Class-based FCFS)을 설계한다. 본 논문에서 제안한 알고리즘의 구현을 위해서 OPNET 시뮬레이션 도구를 이용하였으며, 단대단 처리지연 시간과 버퍼크기를 측정하여 EPON 시스템의 모델로 활용할 수 있는 방안을 제시한다.