• Journal of the Institute of Convergence Signal Processing
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• v.22 no.4
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• pp.164-170
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• 2021

Research was conducted to analyze and improve the kinetic performance of offshore wind power generators. The shape used in this study was taken with reference to the previous paper, and the size of the repair area was designed at 80%, 60%, 40%, and 20%, respectively, and the exercise performance was confirmed accordingly. The sea state was calculated in Sea State 4, 5, and 6. In the calculation process, the calculation was performed using commercial computational hydrodynamics (ANSYS) and AQUA. In the case of overall exercise performance, it was confirmed that the smaller the size of the repair area, the smaller the exercise such as heave, roll, and pitch. However, it was confirmed that in the case of a shape in which the size of the repair area was rapidly reduced, there may be cases in which the restoration performance was not satisfied when the restoration calculation was performed. In addition, it was confirmed that there may be an appropriate repair surface depending on the sea condition.

• Journal of the Society of Naval Architects of Korea
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• v.35 no.4
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• pp.87-97
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• 1998

One of good ways to make a ship perform well in rough seas is to reduce its waterplane area and accordingly is subject to a reduced wave exciting forties. However, a great reduction of the waterplane area may create a penalty in speed performance due to the increased ratio of the wetted area to the displacement volume. This paper suggests a new catamaran hull form which compromises the speed and seakeeping quality by increasing the waterplane area somehow compared with that of the conventional SWATH ship. A 350 passenger carrying SWATH ship with a cruising speed of 30 knots in sea state of 4 has been developed and its performance was validated by the model tests. The design concept resistance performance and seakeeping dualities of the design craft are presented together with its comparative performance comparison with other high speed crafts.

• Journal of the Korea Institute of Building Construction
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• v.18 no.6
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• pp.621-631
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• 2018

The repair and maintenance cost of domestic public rental housing is an issue of considerable interest and growing financial concern. This paper suggests a quantity-based model as an alternative method for predicting costs, instead of the conventional model which is based on actual cost data. Furthermore, this paper provides a forecast of the repair costs incurred each year during the multi family house's maintenance phase (40 years). The recently changed the long-term repair plan and quality-improved interior materials were considered into the research. In order to estimate the cost of maintenance work, 5 sample apartments were selected and analyzed. The repair and maintenance cost from the case studies was converted to cost per household and per floor area for general use. On the other hand, the net present value method was applied to reflect the effect of time. We expect that the results will help to establish expenditure plans that are more effective for public rental housing in the maintenance stage.

• Journal of the Korean Institute of Navigation
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• v.12 no.3
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• pp.39-53
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• 1988

반 잠수식 저 수선면적 쌍동선(Small WAterplane Area Twin Hull) 의 총 저항 추정을 위한 새로운 전산 program 개발에 대해서 개략적으로 설명하였다. SWATH ship의 총저항을 조파 저항, 표면 마찰 저항, Fin 저항 및 부가 저항의 합으로 계산하였다. 개발된 program의 정확성을 확인하기 위해서 수치 해석결과를 세 가지 SWATH 모델들의 실험치와 비교하였다.

• Journal of the Korea Institute of Building Construction
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• v.24 no.3
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• pp.355-362
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• 2024

The sustained upkeep of apartment buildings necessitates ongoing maintenance and timely repairs, particularly given their complex nature due to extensive areas, common facilities, and multiple residential and service structures. Additionally, the need for cost-effective maintenance is paramount for ensuring safety, preserving value, and maintaining economic efficiency. However, the multitude of external variables influencing apartment complex maintenance, coupled with the challenges in data collection, have resulted in limited research in this domain. To address this gap, the current study aims to develop a framework for predicting maintenance costs utilizing deep learning techniques, grounded in real-world apartment complex maintenance cost data. This study intends to provide a practical and valuable contribution to the field of apartment complex management, empowering stakeholders with enhanced predictive capabilities for optimizing maintenance strategies and resource allocation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1140-1141
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• 2017

Depth of SWASH(Small Waterplane Area Single Hull) vessel which is an input value of its control system is measured by ultrasonic sensor. Distance to the its center of gravity can be simply calculated through ultrasonic sensor attached to the front of the vessel from the known values. However, it is to be calibrated with respect to its position for the accurate depth because it has geometric relation between the measurement value of ultrasonic sensor and the depth. In this research, depth calibration method of SWASH vessel using its position and ultrasonic sensor is introduced.

• 한국기계연구소 소보
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• s.17
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• pp.157-165
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• 1987

The SWATH concept hull form which is capable of high speed navigation with small oscillatory motions in waves, was developed from the catamaran type hull forms. This paper describes how the motion of a SWATH ship in irregular waves can be reduced by regulating the stabilizing fins. The optimal regulator and LQG (Linear Quadratic Gaussian) controller for vertical plane motion have been applied for both platforming mode and contouring mode controls. The calculations of hydrodynamic coefficients and external forces are possible for defining the system equation for the design purpose of motion control. Performances of the controlled system are compared with those of original system.

• Bulletin of the Society of Naval Architects of Korea
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• v.23 no.4
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• pp.35-43
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• 1986

Recently, the SWATH concept hull form which is capable of high speed navigation with small oscillatory motions in waves, was developed from the catamaran type hull forms. This paper discribes a method to predict motion responses of a SWATH ship in regular waves using the strip theory. The 2-dimensional hydrodynamic problem was solved using the improved Green integral equation which is free from the irregular frequencies. The effects of viscous drag which is dominant in heave damping of the SWATH ship are taken into account. Further, the effects of the stationary stabilizing fins which is important in high speed performance of the SWATH ship are included in the equation of motions. It seems that the motion responses calculated by the present method show better agreement with experimental results than other existing numerical results.

• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.2
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• pp.1-12
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• 1989

This paper presents a method of minimizing the wave resistance components, due to the linear wave propagating to the far field and the breaking wave in the vicinity of the hull. This method consists of the linear optimization method for the linear wave resistance and the statistical optimization method for the breaking wave resistance through the analysis of the experimental data. For the purpose of the application, a wall-sided model with parabolic waterplane shape was selected as a basic hull form, and two modified hull forms with varied $C_p-curve$ of the fore-body were derived from the linear wave optimization method and the empirical method. The correlation between the linear wave resistance and the breaking wave resistance according to the $C_p-curve$ variation of the fore-body was investigated through the experimental and analytical results for the three hull forms. The fore-body shape optimized by the present method shows the reduction of the wave resistance by 47% comparing to the basic hull form at the design speed($F_n=0.26$).

• Korean Journal of Construction Engineering and Management
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• v.16 no.2
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• pp.29-37
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• 2015

Multi-household buildings are efficiently maintained from the mid- and long-term viewpoint according to the long-term repair coverage system etc. On the other hand, public buildings are not systematically maintained due to a lack of past maintenance cost data and inefficient budget plans, among other problems. Targeting public buildings in Incheon, this study analyzed operation costs variables. To verify the analysis results, they underwent a correlation analysis and a multi-regression analysis. With regard to public buildings electricity, gas and tap water cost, the influence power of the served life, floor area, and workforce were analyzed, revealing that electricity cost was highly correlated with workforce, while gas and tap water cost were correlated with tap water cost. Also, the correlation analysis results were verified through a multi-regression analysis, and a maintenance cost estimation model was presented using a regression equation.