• Nuclear Engineering and Technology
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• 제55권2호
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• pp.690-695
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• 2023

Recommendations are given to improve the efficiency of radiation protection of transport casks for SNF transportation. The attenuation of ${\gamma}$-quanta of long-lived isotopes ¹³⁴Cs, ^137mBa(¹³⁷Cs), ¹⁵⁴Eu and ⁶⁰Co by optimizing the thicknesses and arrangement of layers of Fe and Pb radiation shields of transport casks is studied. The fixed radiation shielding mass (fixed mass thickness) is chosen as the main optimization criterion. The effect of the placement order of Fe and Pb layers in a combined two-layer radiation shield with an equivalent thickness of 30 cm is studied in detail. It is shown that with the same mass thicknesses of the Fe and Pb layers, the placement of Fe in the first layer, and Pb - in the second one provides more than twofold attenuation of ${\gamma}$-quanta compared to the reverse placement: Pb - in the first layer, Fe - in the second. The increase in the efficiency of attenuation of ${\gamma}$-quanta for TC with combined shielding of Fe and Pb is shown to be achieved by designing the first layer of radiation shielding around the canister with SNF from Fe of the maximum possible thickness.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.185-189
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• 2003

According to opening Seoul-Busan high speed rail line in 2004, we are studying to offer speedily for the parcel service of high speed rail-combined transport as it does, tender the quality freight services within a one and the same high speed train formation. Therefore, we reviewed for various types of HSR-combined transport and suggested to application methods in Korean high speed rail line. Through these kinds of approaches, we are able to expect the fulfillment of customer needs for high speed rail market segments, the profit maximization of future railway operating companies, and enhancement for cost-effective rail network operation of the mixed traffic on infrastructure cost-reduction in national logistics.

• 한국세라믹학회지
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• 제42권9호
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• pp.613-617
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• 2005

We present the results of a combined magnetization, dc and magneto-transport study of the n = 2 Ruddlesden-Popper compound $Ca_3Mn_2O_7$ The negative thermoelectric powder is observed. The magnetic measurement data show that there is sharp magnetic transition at 134 K. However, the de and magnetoresistance of $Ca_3Mn_2O_7$ show no particular transport. Transport properties of the compound $Ca_3Mn_2O_7$ are interpreted in terms of activated hopping of small polarons in non-adiabatic regime. Polarons are most probably formed around $Mn^{3+}$ sites created by oxygen sub-stoichiometry.

• ETRI Journal
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• 제22권3호
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• pp.19-26
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• 2000

We describe a detailed numerical scheme to calculate electron transport in quantum wires using the Green function formalism combined with tight-binding orbital basis. As an example of the application, we study the electron transport in a Si nanowire containing a finite potential barrier. The effects of nonzero bias, temperature, and disorder on the barrier-induced oscillatory conductance are investigated within the context of coherent transport model. The oscillatory behavior of the conductance as a function of the Fermi energy is found to be highly sensitive to sample disorder and limited to a very low temperature and a small bias range.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.1551-1555
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• 2006

Korea Railroad Research Institute(KRRI) conducted a survey on the elements for the problems in using TCR and TSR for combined transportation forwarders of Korea for the period from July 2006 to August 2006. The purpose of this paper is to introduce the problems at the time of using, and to prospects the future use condition of international railway.

• 대한교통학회지
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• 제23권5호
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• pp.157-167
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• 2005

서울시 통합대중교통체계개편에 의한 준공영제 및 거리비례오금제의 시행으로 대중교통 수입금정산문제가 한국철도공사, 서울지하철공사, 서울특별시도시철도공사, 인천지하철공사의 기존도시철도운영기관의 수입금 배분 문제가 내재된 상태에서 버스와 도시철도의 수단간 배분문제까지 포함하는 복잡한 문제로 전개되었다. 또한 추가로 계획되고 있는 민자노선, 지자체의 경전철 도입계획으로 향후 대중교통수입금 정산은 보다 다양한 운영기관 및 지역의 협상문제로서 매우 복잡하게 전개될 것으로 예상되고 있다. 본 연구는 대중교통운영기관의 수입금 배정의 기본접근모형을 제시하는 것으로, 운영기관이 통합대중교통망에서의 승객수송에 기여한 정도를 파악하는 것을 핵심으로 하고 있다. 이를 위해 향후 전자지불시스템이 완비되었을 상황을 가정하여 이때에서 환승구간 때문에 승객의 통행행태가 파악되지 않는 수도권 도시철도로 한정하여 역간의 (복수의) 통행경로를 파악하고 수요를 배정하여 운영기관의 인-Km등의 기여도를 계산하는 방안을 제안하다. 본 연구의 주요내용을 요약하면 다음과 같다. 1. 도시철도의 승객의 환승행태를 반영한 일반화 비용. 2. 역간 유사경로결정을 위한 K경로알고리즘. 3. 유사경로에 수요배정모형.

• 무역상무연구
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• 제51권
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• pp.285-313
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• 2011

There can be analyzed severally on the acceptance conditions of freight forwarder's transport document under UCP. First, Bills of Lading issued by forwarding agents will be refused. This can be seen in the article 20 of 1933 Revision UCP(Brochure 82) and the article 20 of 1951 Revision UCP(Brochure 151). Second, Unless specifically authorized in the credit, Bills of Lading issued by forwarding agent will be rejected. It is prescribed in the front part (a) of article 17 of 1962 Revision UCP(Brochure 222) and the article 19 of 1974 Revision UCP(Publication No. 290). Third, Acceptance conditions are different according to the type of transport documents, that is either Bill of Lading or not. It is prescribed in the art 25 and article 26 of 1983 Revision UCP. Unless otherwise stipulated in the credit, transport document issued by a freight forwarder will be rejected unless it is the FIATA Combined Transport Bill of Lading approved by the International Chamber of Commerce or otherwise indicates that it is issued by a freight forwarder acting as a carrier or agent of a named carrier. On the other hand, unless otherwise stipulated in the credit, marine bill of lading issued by a freight forwarder will be rejected, unless it indicates that it is issued by such freight forwarder acting as a carrier, or as the agent of a named carrier. Fourth, transport documents issued by a freight forwarder will be accepted. This can be found in the article 30 of 1993 Revision UCP(ICC Publication No. 500) and the article 14 l of 2007 Revision UCP(ICC Publication No. 600). According to the former unless otherwise authorized in the Credit, transport document issued by a freight forwarder will only be accepted if it is appears on its face to indicate the name of the freight forwarder as a carrier or multimodal transport operator or its agent. The latter prescribed that a transport document will be accepted if it is issued by a freight forwarder by a agent of carrier or freight forwarder itself.

• ETRI Journal
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• 제32권2호
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• pp.281-291
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• 2010

Scalable video coding (SVC) has been standardized as an extension of the H.264/AVC standard. This paper proposes a practical real-time transport protocol (RTP) packetization scheme to transport SVC video over IP networks. In combined scalability of SVC, a coded picture of a base or scalable enhancement layer is produced as one or more video layers consisting of network abstraction layer (NAL) units. The SVC NAL unit header contains a (DID, TID, QID) field to identify the association of each SVC NAL unit with its scalable enhancement layer without parsing the payload part of the SVC NAL unit. In this paper, we utilize the (DID, TID, QID) information to derive hierarchical spatio-temporal relationship of the SVC NAL units. Based on the derivation using the (DID, TID, QID) field, we propose a practical RTP packetization scheme for generating single RTP sessions in unicast and multicast transport of SVC video. The experimental results indicate that the proposed packetization scheme can be efficiently applied to transport SVC video over IP networks with little induced delay, jitter, and computational load.

• 한국ITS학회 논문지
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• 제19권6호
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• pp.152-162
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• 2020

도농복합지역에서는 택시가 영업을 목적으로 도심지에서 농촌 지역으로 이동한 뒤 공차로 회차할 시 손실을 보전해주는 복합할증제도를 운영하고 있다. 하지만, 제도의 본 취지와 다르게 기형적으로 운영되는 복합할증제도로 인해 폐지와 관련된 민원이 증가하고 있다. 복합할증제도 폐지 시 택시업계는 수익감소로 큰 타격을 받을 수 있어 지자체의 지원이 불가피하다. 하지만, 실제 수입금의 감소분을 고려한 보조금의 규모 책정이 현실적으로 어려운 실정이다. 본 연구에서는 도농복합지역(예:통영시)의 법인택시에 장착된 디지털 운행기록계로부터 수집된 DTG 데이터와 영업데이터를 연계 분석하여 복합할증제도 폐지 시 감소하는 수입금을 과학적이고 객관적인 방법으로 추정해보고자 한다. 본 연구는 실제 지역의 현안을 해결하기 위해 DTG 데이터를 이용했다는 점과 새로운 DTG 데이터의 활용을 제시했다는 측면에서 의의가 있다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.22-27
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• 2006

This paper describes the development of the stream-tube based dispersion model for modeling contaminant transport in open channels. The operator-splitting technique is employed to separate the 2D contaminant transport equation into the pure advection and pure dispersion equations. Then the total variation diminishing (TVD) schemes are combined with the second-order Lax-Wendroff and third-order QUICKEST explicit finite difference schemes respectively to solve the pure advection equation in order to prevent the occurrence of numerical oscillations. Due to various limiters owning different features, the numerical tests for 1D pure advection and 2D dispersion are conducted to evaluate the performance of different TVD schemes firstly, then the TVD schemes are applied to experimental data for simulating the 2D mixing in a straight trapezoidal channel to test the model capability. Both the numerical tests and model application show that the TVD schemes are very competent for solving the advection-dominated transport problems.