• 한국항해항만학회지
• /
• 제46권1호
• /
• pp.33-41
• /
• 2022

컨테이너 터미널의 중요한 운영 목표는 선박에 컨테이너를 싣고 내리는 안벽 크레인(QC: quay crane) 작업의 효율을 극대화하는 것이다. QC 작업 효율의 극대화를 위해서는 장치장과 QC 사이를 오가며 컨테이너를 운반하는 내부트럭(YT: yard tractor)의 운행 지연이 최소화되어야 하는데, 터미널 내부의 교통 정체가 이를 어렵게 하는 경우가 많다. 본 논문에서는 YT와 외부트럭이 혼재하여 다니는 터미널에서YT의 운영 데이터만을 기반으로 터미널 내부 교통 속도를 예측하는 모델을 학습하는 방안을 제안한다. 외부트럭에 대한 교통 데이터는 구할 수 없지만, 대신 YT 운영 데이터에는 가까운 미래의 YT 운행 경로에 관한 정보가 포함되어 있어서 교통 예측에 상당한 도움이 된다. 시뮬레이션 실험 결과 제안 방안으로 학습한 모델이 상당히 정확한 수준으로 교통 속도를 예측할 수 있음을 확인하였다.

• 설비공학논문집
• /
• 제20권12호
• /
• pp.775-780
• /
• 2008

A dynamic model to simulate LNG reliquefaction process has been developed. The model was applied to two candidate cycles for LNG reliquefaction process, which are Reverse Brayton and Claude cycles. The simulation was intended to simulate the pilot plant under construction for operation of the two cycles and evaluate their feasibility. According to the simulation results, both satisfy control requirements for safe operation of brazed aluminum plate-fin type heat exchangers. In view of energy consumption, the Reverse Brayton cycle is more efficient than the Claude cycle. The latter has an expansion valve in addition to the common facilities sharing with the Reverse Brayton cycle. The expansion valve is a main cause to the efficiency loss. It generates a significant amount of entropy associated with its throttling and increases circulation flow rates of the refrigerant and power consumption caused by its leaking resulting in lowered pressure ratio. It is concluded that the Reverse Brayton cycle is more efficient and simpler in control and construction than the Claude cycle.

• 지질공학
• /
• 제33권4호
• /
• pp.627-638
• /
• 2023

본 연구에서는 김천부항댐이 위치한 감천유역을 대상으로 댐운영에 따른 하류하천 유량의 공간적인 변동성을 평가하고자 하였다. 특히, 다목적댐의 주요기능인 치수적인 측면에서의 홍수저감과 이수적인 측면에서의 갈수기 유량확보 효과를 정량적으로 분석하였다. 대상유역에 대하여 SWAT-K 모델링을 수행하여, 댐 하류하천의 4개 수위관측지점 관측유량과 모의유량을 비교한 결과, R²와 NSE 모두 0.75 이상의 적합도를 확보하였다. 댐의 홍수저감효과의 공간적 분석을 위해 연최대 홍수량을 중심으로 분석한 결과, 4개 지점에서의 홍수저감율은 8.5~25.0%로 나타났다. 갈수기 유량확보 효과에 대해서는 유황곡선을 중심으로 평가하였으며, 특히 평균갈수량의 경우에는 33~198%의 유량증가가 이루어짐을 알 수 있었다.

• Nuclear Engineering and Technology
• /
• 제52권9호
• /
• pp.2138-2150
• /
• 2020

We report the status of the cold neutron triple-axis spectrometer (Cold TAS) and thermal neutron triple-axis spectrometer (Thermal TAS) installed at HANARO. Cold TAS, whose specifications are standard across the world, is in the final phase of commissioning. Proper instrument operation was confirmed through a feasibility study of phonon measurements and data analyses with resolution convolution. In contrast, Thermal TAS is in the initial phase of commissioning, and improvement of the monochromator drum is now in progress from the viewpoint of radiation shielding. In addition, we report recent activities in the development of neutron basic elements, that is, film-coated Si-wafer collimators, which are promising for use in triple-axis spectroscopy, particularly in Cold TAS.

• Journal of electromagnetic engineering and science
• /
• 제16권3호
• /
• pp.194-197
• /
• 2016

An eight-element compact low-profile multi-input multi-output (MIMO) antenna is proposed for wireless local area network (WLAN) mobile applications. The proposed antenna consists of eight inverted-F antennas with an isolation-enhanced structure. By inserting the isolation-enhanced structure between the antenna elements, the slot and capacitor pair generates additional resonant frequency and decreases mutual coupling between the antenna elements. The overall size of the proposed antenna is only $33mm{\times}33mm$, which is integrated into an area of just $0.5{\lambda}{\times}0.5{\lambda}$. The proposed antenna meets 5-GHz WLAN standards with an operation bandwidth of 4.86 - 5.27 GHz and achieves an isolation of approximately 30 dB at 5 GHz. The simulated and measured results for the proposed antenna are presented and compared.

• Corrosion Science and Technology
• /
• 제18권6호
• /
• pp.277-284
• /
• 2019

External corrosion control of buried pipe can be achieved by the combination of barrier coating and cathodic protection. Coating damage and deterioration can be induced by many reasons; damage during handling and laying, enhanced failure at low temperatures, failure during commissioning and operation, disbanding due to inadequate surface cleaning, rock penetration during installation and service etc. This work focused on the effect of survey conditions on the reliability of coating flaw detection of buried pipes. The effects of applied voltage and anode location on the detection reliability of coating flaw of buried pipe in soil with the resistivity of ca. 25.8 kΩ·cm were discussed. Higher applied voltage increased the detection reliability, regardless of buried depth, but deeper burial depth reduced the reliability. The location of the anode has influenced on the detection reliability. This behaviour may be induced by the variation of current distribution by the applied voltage and buried depth. From the relationship between the applied voltage and reliability, the needed detection potential to get a desire detection reliability can be calculated to get 100% detection reliability using the derived equation.

• ETRI Journal
• /
• 제34권2호
• /
• pp.256-259
• /
• 2012

The double-base number system has been used in digital signal processing systems for over a decade because of its fast inner product operation and low hardware complexity. This letter proposes an innovative multiplier architecture using hybrid operands. The multiplier can easily be linked to flash analog-to-digital converters or digital systems through a double-base number encoder (DBNE) for realtime signal processing. The design of the DBNE and the multiplier enable faster digital signal processing and require less hardware resources compared to the binary processing method.

• 한국터널지하공간학회 논문집
• /
• 제16권2호
• /
• pp.203-211
• /
• 2014

본 논문은 shield TBM의 버럭 배토장비인 screw conveyor의 최적 버럭 배토효율에 관한 연구이다. screw conveyor의 배토효율에 영향을 미치는 주요 Parameter인 screw 형태(Shaft식, Ribbon식), screw conveyor와 screw 각도의 영향을 분석하기 위하여 축소모형시험을 실시하였다. 축소모형시험을 통해 구한 버럭 배토 효율과 기존 이론식을 통해 구한 최적의 버럭 배토효율을 비교 분석하여 최적의 screw 형태, screw conveyor와 screw각도를 도출 할 수 있었다. 결론적으로 축소모형시험을 통하여 screw conveyor 설계인자들에 대하여 제시하였다. 또한 이 연구 결과는 향후 shield TBM 기술을 발전시키는데 유용할 것으로 기대된다.

• Journal of Microbiology and Biotechnology
• /
• 제2권1호
• /
• pp.41-45
• /
• 1992

Shikonin production was examined in a bubble column bioreactor system with the hairy roots of Lithosphermum erythrorhizon. The volumetric productivity was higher than those obtained from other reactor configurations with free or immobilized cells of the same cell line. The productivities of the bubble column reactor, with and without a product absorption trap, were 7.4 and 4.5 mg of shikonin/l/d, respectively. This indicated the importance of the product removal in the design and operation of the shikonin production system with hairy root culture.

• 한국세라믹학회지
• /
• 제47권1호
• /
• pp.75-81
• /
• 2010

The feasibility of using the thin film technology in utilizing lanthanum strontium manganite (LSM) for a solid oxide fuel cell (SOFC) cathode in a low-temperature regime is investigated in this study. Thin film LSM cathodes were fabricated using pulsed laser deposition (PLD) on anode-supported SOFCs with yttria-stabilized zirconia (YSZ) electrolytes. Although cells with a 1 ${\mu}m$-thick LSM cathode showed poor low-temperature cell performance compared to that of a cell with a bulk-processed cathode due to the lack of a triple-phase boundary length, the cell with 200 nm-thick gadolinia-doped ceria (GDC) inserted between the LSM and YSZ showed enhanced performance and more stable operation characteristics in a comparison of a cell without a GDC layer. We postulate that the GDC layer likely improved the cathode adhesion, therefore contributing to the improvement of the cell performance instead of serving as an interfacial reaction buffer.