• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.3
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• pp.198-210
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• 2006

POM(Princeton Ocean Model) was utilized in this study because it took ${\sigma}-coordinate$ system which could predict the behavior of bottom water. The model has been increasingly applied to costal area although it was initially developed as the ocean flow model. The original POM did not correct computational errors in transformation of ${\sigma}-coordinate$ system. The trying to reduce conversional errors might improve accuracy of flow velocity in vicinities of bottom layer. Therefore, in this study it was proposed to modify the original POM by using error correction method suggested by $Sl{\Phi}rdal$(1997). The modified POM was applied to Young-rang Lake, one of the typical brackish lakes in Korea. It was found that the behavior of bottom water could be well predicted. Thus, it seems that the modified POM can be used as a useful tool to clarify the mechanism of formation and behavior of bottom water including oxygen-deficient water mass.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.1
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• pp.63-78
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• 2009

This paper presents the development of dynamically combined Typhoon generated surge-tide-wave numerical model which is applicable to shallow water. The newly developed model is based on both POM (Princeton Ocean Model) for the surge and tide and WAM (WAve Model) for wind-generated waves, but is modified to be applicable to shallow water. In this paper which is the first paper of the two in a sequence, we verified the accuracy and numerical stability of the hydrodynamic part of the model which is responsible for the simulation of Typhoon generated surge and tide. In order to improve the accuracy and numerical stability of the combined model, we modified algorithms responsible for turbulent modeling as well as vertical velocity computation routine of POM. Verification of the model performance had been conducted by comparing numerical simulation results with analytic solutions as well as data obtained from field measurement. The modified POM is shown to be more accurate and numerically stable compare to the existing POM.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.1
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• pp.72-82
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• 2015

In order to effectively and economically apply the previous POM(Princeton Ocean Model) WAD(Wetting And Drying) to the coastal area, the POM WAD was modified such as the water elevation input of tidal harmonics in the open boundaries was included and a CTS(Computing Time Saving) technique was introduced to the model. The modified model was tested to the standing waves in the rectangular bay and the hydraulic experiments for the flow and heat diffusion in the 3D basin. The numerical results showed a good agreement with the analytical solutions of the standing waves and the observed values by the hydraulic experiments, respectively. And also when the modified model with the CTS technique was applied to Gwangyang Bay of Korea, the computing time was decreased by as much as 39.4%.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2002.03b
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• pp.61-68
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• 2002

GIS와 하천수질 모델링과의 연계에 관한 연구는 점점 많아지고 계속되고 있는 실정이다. 그러나 해양모델링과 GIS와 연계한 연구는 많지 않다. 이번 연구에서는 해양모델을 GIS와 연계하는 측면을 고려해 보았다. 해양모델 중에 해수유동에 관한 모델 POM(princeton Ocean Model)을 선정하여 해양모델의 구동을 위해 자료를 만드는 것과 결과물을 도시하는 데 있어서 GIS를 사용한다. 그래서 기존의 해양모델을 사용하는 측면에서의 편이성을 도모하고, 또한 해양모델의 구동을 위해 자료 만드는 측면에서 정확성을 높이게 한다.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2002.11a
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• pp.4-10
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• 2002

색지와 무늬지를 주로 생산하는 팬시지 공장의 경우 고객의 다양한 기호와 수요에 대응하기 위해서는 잦은 색상 및 지종교체가 필요하다. 기존 wet-end 시스템과 color control 시스템으로는 높아진 고객의 품질 욕구를 충족하기 어려울 뿐만 아니라 잦은 지종교체로 인한 생산성, 원가, 조업안정성 등의 손실을 수반한다. 이에 당사는 wet-end volume을 획기적으로 줄여 빠른 응답시간의 장점이 있는 POM 시스템(compact papermaking system) 과 on-line color control이 가능한 CLCC (closed loop color control) 시스템을 동시에 적용하여 각각의 장점을 활용한 지종 교체시간 단축과 색상의 균일성을 확보한 사례이다.

• Journal of Navigation and Port Research
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• v.32 no.3
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• pp.245-250
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• 2008

Recently the numerical prediction technique is applied to many fields, because numerical models are developed so much for last decades. The real-time ocean prediction system is one of them and is capable of providing the real-time marine information for users to promote the safety af maritime traffic and preservation of marine resources. The system is composed of observing system, data distribution system and modelling system. In this study authors develop the modelling system and show the results as preliminary study for establishing the real-time ocean prediction system in Busan port. The system test is performed only for M2 tidal modelling due to the lack qf observation data, thus a full-scale test is required in future if enough data are provided Also observing system and data distribution system will be constructed continuously in future, then service for real-time data for users will be initiated.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.100-103
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• 2007

근래 컴퓨터 수치모델이 급속하게 발전함으로써 다양한 분야에서 수치예보기술이 응용되고 있다. 실시간 해양예보시스템도 그중의 하나로 관측시스템, 정보제공시스템, 그리고 모델링시스템으로 구성되며, 이는 실시간 해양정보를 제공함으로써 해상교통의 안전과 연안환경의 보호에 기여한다. 본 연구에서는 부산항 실시간 해양예보시스템의 구축을 위한 기초연구로써 부산항 모델링시스템을 개발하였으며 그 결과를 제시한다. 기존 관측자료가 부족하여 M2조석 모델링만으로 시스템의 테스트를 수행하였으나 앞으로 관측시스템이 완비되면 종합적인 테스트가 요구된다. 아울러 앞으로 관측시스템 및 정보제공시스템이 계속해서 구축될 예정이며 이들 시스템이 모두 완비되고 나면 인터넷을 통한 실시간 정보제공이 이루어지게 될 것이다.

• Journal of IKEEE
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• v.23 no.2
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• pp.594-598
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• 2019

We demonstrate an alternative alignment process using transferring process on solution driven HfZnO film. Parallel pattern is firstly fabricated on a silicon wafer by laser interference lithography. Prepared HfZnO solution fabricated by sol-gel process is spin-coated on a glass substrate. The silicon wafer with parallel pattern is placed on the HfZnO film and annealed at $100^{\circ}C$ for 30 min. After transferring process, parallel grooves on the HfZnO film is obtained which is confirmed by atomic force microscopy and scanning electron microscopy. Uniform liquid crystal alignment is achieved which is attributed to an anisotropic characteristic of HfZnO film by parallel grooves. The liquid crystal cell exhibited a pretilt angle of $0.25^{\circ}$ which showed a homogeneous alignment property.

• Korean Journal of Ecology and Environment
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• v.49 no.2
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• pp.80-88
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• 2016

In order to reconstruct a benthic foodweb structure and assess the role of benthic microalgaes as a diet source for benthos, we analyzed the carbon and nitrogen stable isotopes of diverse benthos (bivalves, crustaceans, gastropods and fishes) and potential diets (particulate organic matter, sedimentary organic matter, benthic microalgae, seagrass, and macroalgaes) in the intertidal mudflat surrounding Yeongheung Island. The ${\delta}^{13}C$ values of the diets indicated wide ranges (- 26.5‰ to - 8.4‰) while benthos showed a small range of ${\delta}^{13}C$ values (-12.1‰ to - 17.8‰), although they were in the same range. Except for green algaes among the macroalgaes as well as sedimentary organic matter, ${\delta}^{15}N$ values of the diet candidates ($5.7{\pm}1.0$‰) were lighter in comparison to those of the benthos ($11.8{\pm}1.9$‰). Based on the ${\delta}^{13}C$ and ${\delta}^{15}N$ data, the benthos were classified into 3 groups, indicating a different diet and trophic position. But benthic microalgae is the most important diet source for all three benthos groups based on their stable isotope ratios, suggesting benthic microalgae should be a main diet to the intertidal ecosystem. Hence this study highlights that the biomass of benthic microalgae as biological resource should be evaluated for the management of the intertidal ecosystem of Yeongheung Island.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.3
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• pp.75-86
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• 2003

In the near future, the capacity of conventional anaerobic digester is thought to be insufficient because of the increase of the total solids from expansion of intercepting sewer, sewage quantity and direct input of night soil from near apartment districts. The objectives of this study was to investigate the improvement of digestion efficiency using microbial agent(Bio-dh). The system was a pilot-scale, two-staged, anaerobic sludge digestion system. The first-stage digester was heated and mixed. The agitation velocity of the first-stage digester was 120rpm. The second-stage digester was neither heated nor mixed. The Digestion temperature was kept at $35{\pm}1^{\circ}C$ The detention time of digester was 19 days. The dosage of sewage sludge and microbial agent were $0.65m^3/day$ and $0.5{\ell}/day$, respectively. The experiments was run for 25days. Three times a week, $COD_{Mn}$ and SS of effluent, TS, VS, and biogas production rate were measured. Temperature, pH, and alkalinity were measured daily. The results were as follows ; Without microbial agent, digestion efficiencies ranged 46.0%~50.9%(mean=48.6%), with microbial agent(Bio-dh), digestion efficiencies ranged 52.8%~57.3%(mean=54.2%). Consequently, microbial agent(Bio-dh) increased the sludge digestion efficiency about 12%. Also, Without microbial agent, the mean concentration of $COD_{Mn}$ and SS of second-stage digester effluent were 1,639mg/L, 4,888mg/L respectively. With microbial agent, the mean concentration of $COD_{Mn}$ and SS of second-stage digester effluent were 859mg/L, 2,405mg/L respectively. Consequently, microbial agent(Bio-dh) increased the removal efficiency of $COD_{Mn}$ and SS about 47.6% and 50.8%, respectively.