• 한국해양공학회지
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• 제13권4호통권35호
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• pp.151-158
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• 1999

A model harbour with Plan scale of $1.08{\times}1.08m$ is built on a tidal tank using a Froude relationship from a real harbour($432{\times}432m$). Velocity components are measured by a ultrasonic velocity meter and flow structure is then predicted using a 2-D depth integrated hydrodynamic model. In the finite difference model implemented in this study, various wall boundary conditions, i.e. no-slip, free-slip, partial-slip and semi-slip are used to represent turbulent diffusion terms, e.g. ${\partial}^2U_{ij}/{\partial}x^2\;or\;{\partial}^2U_{ij}/{\partial}y^2$. These conditions are focused to investigate their influence on the flow structure along the wall and basin of the harbour with aspect ratio of unity, i.e. Length/Breadth. Numerical experiments are compared with the measurements and used to analyse flow patterns in the basin during tidal cycles. It is shown from the results that no-slip closed boundary condition is the most appropriate method with respect to the location of the eddy centre, although the condition underestimates velocity components along the wall.

• 한국언어정보학회:학술대회논문집
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• 한국언어정보학회 1996년도 Language, Information and Computation = Selected Papers from the 11th Pacific Asia Conference on Language, Information and Computation, Seoul
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• pp.63-72
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• 1996

• Geomechanics and Engineering
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• 제1권3호
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• pp.241-257
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• 2009

The one-dimensional compressibility of sand is an important property for the estimation of settlement or deformation of sand deposits. The $K_0$ value of sand is also an important design parameter. Experimental results are presented in this paper to study the compressibility of sand in $K_0$ consolidation tests. The $K_0$ consolidation tests were carried out using a triaxial cell and a plane-strain apparatus. Specimens prepared using both the moist tamping and the water sedimentation methods were tested. The testing data demonstrate that the type of testing apparatus does not affect the $K_0$ measurement if proper boundary conditions are imposed in the tests. The data also show that the compressibility and the $K_0$ value of loose sand specimens prepared using the moist tamping method are very sensitive to the variation of void ratio. The $K_0$ values measured from these tests do not agree with the $K_0$ values calculated from Jaky's equation. The compressibility and $K_0$ values of sand obtained from tests on specimens prepared using different preparation methods are different which may reflect the influence of soil fabrics or structures on the one dimensional compression behavior of sand.

• 한국항해항만학회지
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• 제33권5호
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• pp.323-330
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• 2009

병렬기구를 이용하여 항만공사를 위한 수중로봇을 개발하였다. 수중으로 큰 피복석을 옮기기 위해 수중로봇은 크레인에 의해 권양된다. 수중로봇의 요오와 피치운동은 유압 실린더에 의해 제어되지만 롤 운동은 제어되지 않는다. 롤 운동을 위해 로봇 양쪽에 프로펠러가 장착되어 제어된다. 본 논문은 수중로봇의 롤 운동제어에 관한 것이다. 롤 운동 각도를 측정하기 위해 자이로 센서가 사용되었다. 로봇의 롤 운동을 2차 비선형 시스템으로 나타내고 반복 리스트 스퀘어 방법과 적응인식 방법으로 동적 모델을 찾았다. 동적 모델로 외란을 보상하기 위한 제어입력을 계산하고 PD 제어, 반복 리스트 스퀘어 모델 베이스 제어, 적응 모델 베이스 제어를 롤 운동제어에 적용했다. 수중로봇의 시스템을 설명하고 제안한 제어기의 시뮬레이션과 실험결과를 보인다.

• 한국해안해양공학회지
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• 제17권3호
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• pp.149-157
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• 2005

모형의 지배방정식에서 정의되는 대표적인 매개변수는 유역 및 대기로부터의 오염부하량,퇴적물로부터의 오염물질 용출부하량, 확산계수, 반응계수 등으로, 직접적인 관측이 곤란할 뿐만 아니라 많은 관측비용을 필요로 한다. 본 연구에서는 매개변수를 포함한 오염물질 수지방정식을 구성하고, 구성된 선형 연립방정식을 이용하여 계산된 농도분포자료와 관측된 시계열 농도턱포자료를 이용하여 계산한 질량변화량의 차이를 최소화하는 역산문제를 구성하여 모형의 매개변수를 추정하는 방법을 제시하였다. 이 방법을 이용하여 천수만, 울산만(울산항)해 역에서 관측된 연직방향 농도분포 자료를 이용하여 연직 확산계수 및 대기로부터의 오염부하량, 퇴적물로부터의 오염물질 용출부하량, 확산$\cdot$반응에 의한 오염물질 변화량 등을 추정하였으며, 추정 매개변수는 시기적으로 변동이 크게 나타났다. 한편, 관측자료와 추정매개변수를 이용한 계산결과를 비교한 결과, RMS 오차는 괄측자료 범위의 $5.0\%$ 이하, 일치지수는 0.95 이상으로 본 방법을 이용한 매개변수 추정결과의 신뢰성은 우수한 것으로 파악되었다.

• 토지주택연구
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• 제5권1호
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• pp.53-56
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• 2014

Hong Kong, a well-known metropolis characterized by skyscrapers on both sides of the Victoria Harbour, consists mainly of 3 parts, namely the Hong Kong Island, the Kowloon peninsula and the New Territories (N.T.) which is the land area north of Kowloon plus a number of outlying islands. Located in the N.T. are all the new towns, market towns; and in the plains and valleys lie scattered village houses of not more than 3 storeys within the confines of well-defined village. These village houses are governed by a rural housing policy that could be traced back to the very beginning of the former British administration in the N.T. By the Convention of Peking of 1898, the N.T., comprising the massive land area north of Kowloon up to Shenzhen River and 235 islands, was leased to Britain by China for 99 years from 1st July 1898. Soon after occupation, the colonial government conducted a survey of this uncharted territory from 1899 to 1903, and set up a land court to facilitate all land registration work and to resolve disputed claims. By 1905, the Block Crown Leases with Schedule of Lessees and details of the lots, each with a copy of the lot index plan (Demarcation Plan) were executed. Based on the above, Crown rent rolls were prepared for record and rent collection purposes. All grants of land thereafter are known as New Grant lots. After completion and execution of the Block Crown Lease in 1905, N.T. villagers had to purchase village house lots by means of Restricted Village Auctions; and Building Licences were issued to convert private agricultural land for building purposes but gradually replaced by Land Exchanges (i.e. to surrender agricultural land for the re-grant of building land) from the early 1960's until introduction of the current Small House Policy in October 1972. It was not until the current New Territories Small House Policy came into effect in December 1972 that the Land Authority can make direct grant of government land or approve the conversion of self-owned agricultural land to allow indigenous villagers to build houses within the village environs under concessionary terms. Such houses are currently restricted to 700 square feet in area and three storeys with a maximum height of 27 feet. An indigenous villager is a male descendent of a villager who was the resident of a recognized village already existing in 1898. Each villager is only allowed one concessionary grant in his lifetime. Upon return of Hong Kong to the People's Republic of China on July 1st, 1997, the traditional rights of indigenous villagers are protected under Article 40 of the Basic Law (a mini-constitution of the Hong Kong Special Administrative Region). Also all N.T. leases have been extended for 50 years up to 2047. Owing to the escalating demand and spiral landed property prices in recent years, abuse of the N.T. Small House Policy has been reported in some areas and is a concern in some quarters. The Hong Kong Institute of Land Administration attempts to study the history that leads to the current rural housing policy in the New Territories with particular emphasis on the small house policy, hoping that some light can be shed on the "way forward" for such a controversial policy.