• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 2005.11a
• /
• pp.337-340
• /
• 2005

The aim of this study is to provide primary data to propel business intended for the entire nation through the analytic assessment of the propulsion process of the newly attempted 'Dagagu' Housing Purchase and Public Rental Program (DPPRP) for the cities low income bracket. The study method was to conduct analysis of data, interview survey, onsite tenant interviews and examination of the locale in order to analyze the execution of the program and experiences of the administrator in charge of executing the model program. In the case of the enforcement of the 'Dagagu' Housing Purchase and Public Rental Program(DPPRP), combined teams of the specialty fields of purchase, rental, and management are needed; operation propulsion system of the purchase process of the housing, rental process for selecting the tenant, and the entire process of management afterwards needs to be maintained; and a collaboration system with related organizations need to be constructed.

• Journal of the Society of Naval Architects of Korea
• /
• v.60 no.5
• /
• pp.358-366
• /
• 2023

Due to the International Maritime Organization's (IMO) environmental regulations on NOx and SOx, LNG-fueled eco-friendly ships are gaining attention worldwide, and various eco-friendly ships are being proposed and demanded for conversion to eco-friendly ships in Korea, as the eco-friendly ship law has recently been enforced. In this study, the initial basic design was performed to convert an existing Marine Gas Oil (MGO) fueled ship into an LNG-DF propulsion ship, targeting medium-sized ship, to select the fuel tank capacity and main dimensions and appropriate fuel ratio between the two fuels. In particular, Sustainable basic design method considering environmental impact were proposed by performing a Life Cycle Assessment (LCA) throughout the design process, and various design options were compared and analyzed to meet different design conditions by applying them.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.40 no.7
• /
• pp.653-658
• /
• 2016

High pressure components of a gas turbine engine are generally made of nickel-base superalloys, using precision casting process due to complicated geometries with intricate channels and cooling holes. Turbine components manufactured from directionally solidified and single crystal materials have columnar grains; however, it is found that the crystals do not grow in its preferred direction, although the orientation can be controlled. This anisotropy can lead to the variations of elastic and Hill's parameters in constitutive equations, and they alter stress distributions and the low cycle fatigue life. We aims to evaluate the effects of perturbed crystal orientations on the structural integrity of a directionally solidified nozzle using low cycle fatigue life. We also attempt to show the necessity for the control of allowed manufacturing errors and stochastic analysis. Our approaches included conjugate heat transfer and structural analysis, along with low cycle fatigue life assessment.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.2
• /
• pp.238-247
• /
• 2023

Liquefied petroleum gas (LPG) is an attractive fuel for ships considering its current technology and economic viability. However, safety guidelines for LPG-fueled ships are still under development, and there have been no cases of applying LPG propulsion systems to small and medium-sized ships in Korea. The purpose of this study was to perform an objective risk assessment for the first marine LPG engine system and propose safe operational standards. First, hazard and operability (HAZOP) analysis was used to divide the engine system into five nodes, and 58 hazards were identified. To compensate for the subjectivity of qualitative evaluation using HAZOP analysis, fuzzy set theory was used, and additional risk factors, such as detectability and sensitivity, were included to compare the relative weights of the risk factors using a fuzzy analytical hierarchy process. As a result, among the five risk factors, those with a major impact on risk were determined to be the frequency and severity. Finally, the fuzzy technique for order of preference by similarity to ideal solution (TOPSIS) was applied to select the risk rank more precisely by considering the weights of the risk factors. The risk level was divided into 47 groups, and the major hazard during the operation of the engine system was found through the analysis to be gas leakage during maintenance of the LPG supply line. The technique proposed can be applied to various facilities, such as LPG supply systems, and can be utilized as a standard procedure for risk assessment in developing safety standards for LPG-powered ships.