• Special Issue of the Society of Naval Architects of Korea
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• 2013.12a
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• pp.103-109
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• 2013

The Present work focuses on application of Organic Rankine Cycle - Waste heat Recovery System (ORC-WHRS) for marine diesel engine. ORC and its combined cycle with the engine were simulated and its performance was estimated theoretically under the various engine operation conditions and cooling water conditions. The working fluid, R245fa, was selected for the consideration of the heat source temperature, system efficiency and safety issues. According to the thermodynamic analysis, ~13.1% of system efficiency of the cycle was performed and it is about 4% of the mechanical power output of the considering Marine Diesel Engine. Also, addition of evaporator and pre-heater were studied to maximize output power of Organic Rankine Cycle as a waste heat recovery system of the marine diesel engine.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.4
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• pp.384-394
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• 2020

This paper proposes an outlier detection model based on machine learning that can diagnose the presence or absence of major engine parts through unsupervised learning analysis of main engine big data of a ship. Engine big data of the ship was collected for more than seven months, and expert knowledge and correlation analysis were performed to select features that are closely related to the operation of the main engine. For unsupervised learning analysis, ensemble model wherein many predictive models are strategically combined to increase the model performance, is used for anomaly detection. As a result, the proposed model successfully detected the anomalous engine status from the normal status. To validate our approach, clustering analysis was conducted to find out the different patterns of anomalies the anomalous point. By examining distribution of each cluster, we could successfully find the patterns of anomalies.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.6
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• pp.838-844
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• 2012

This paper proposes the effective monitoring method for marine engine system, which is implemented based upon Controller Area Network (CAN). As the marine engine monitoring system requires various kind of information, a lot of sensor nodes are distributed to several places. The CAN supports huge numbers of message IDs for the sensor nodes and provides a stable communication channel in a wide area such as a 12,000 TEU container ship. Since the CAN is priority-based communication system, some of hard real-time messages like alarm messages which are time-critical to the operation of the vessel cannot be communicated within the dead-time. Therefore it is desirable to distinguish the bandwidth of the CAN for static state messages and transition-state messages not to be harmful to the engine operations. Using the features of message arbitration ability of the CAN, it is proposed in this paper that the bandwidth allocation is dynamically adjusted to cope with the increment of input signal to improve the performance of monitoring system. Effectiveness and validity of the proposed scheme have been demonstrated through real experiments.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.160-165
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• 2005

The proceeding bearings of marine diesel engine are affected by dynamic loads from the cylinder gas pressure and the inertia force from the crank mechanism. Oil film must support the load of the shaft and it also must protect the proceeding and the bearings from damage. This study uses Goenka's new curve fit to carry out the theoretical analysis of oil film in proceeding bearings for MAN B&W 12K90MC-C and Hyundai Heavy Industry Co., Ltd HiMSEN H21/32 Engine. The applied engine's analysis results show the behavior of the proceedings in main and crank pin bearings. The results of this study will be the proper criteria for the proceeding bearings design and be available for development of the new technology in the proceeding bearing and for the high strength lining coating.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.1
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• pp.43-51
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• 2013

This is a thesis about the experiment of comparison characteristic of power and exhaust gas in the same condition between diesel engine that is equipped turbocharger different from response power to increase effectiveness of the engine which is recently used in a lot of industry which requires high power. Resulting of the experiment with natural aspiration diesel engine and turbocharger diesel engine, difference in low speed is not significant, but in high speed, effectiveness of turbocharger diesel engine is much higher than the other one. In other hand, in exhaust gas experiment, turbocharger model exhausts more $NO_X$ and $O_2$, but it doesn't significantly affect the result when it comes with decreasing of $CO_2$ and effectiveness of increased power characteristic. As a result, the turbocharger diesel engine is economically effective comparing with the natural aspiration diesel engine.

• The KSFM Journal of Fluid Machinery
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• v.11 no.2
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• pp.55-63
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• 2008

An examination of the condition of the flow leaving the impeller exit kinetic energy often accounts for 30-50% of the shaft work input to the compressor stage, and for energy efficiency it is important to recover as much of this as possible. This is the function of the diffuser which follows the impeller. The purpose of this study is to investigate the sensitivity of how compressor performances changes as vaned diffuser geometry is varied. Three kinds of vaned diffusers were studied and its results were compared. First vaned diffuser type is based on NACA airfoil and second is channel diffuser and third is conformal transformation of NACA65(4A10)06 airfoil. Mean-line prediction method was applied to investigate the performance and stability for three kinds of diffusers. And CFD analyses have been done for comparison and detailed interior flow pattern study. NACA65(4A10)06 airfoil showed the widest operating range and higher pressure characteristics than the others.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.3
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• pp.176-182
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• 2005

American Conference of Governmental Industrial Hygienists (ACGIH) adopted the Lifting Threshold Limit Values ($TLVs^{(R)}$) in 2005 as a guideline for protecting the workers from work-related low back and shoulder disorders associated with repetitive lifting tasks. The TLVs consist of three tables with recommended weight limits for lifting tasks and their determination procedures are simple. The TLVs sans the material weight/the recommended values (LITLVs) were obtained from 45 lifting tasks in ship engine manufacturing factories. These values were compared and correlated with the Recommended Weight Limits (RWLs) and lifting indices (LIs) determined by the Revised Lifting Equation (LE) of the National Institute for Occupational Safety and Health (NIOSH). The average ratio, LITLVs/LIs, was 0.8 (LITLVs: $1.3{\pm}0.8$, LIs: $1.6{\pm}0.7$). Thus, the TLVs underestimated the risk than the LE. The LITLVs were highly correlated with LIs (r=0.82). The predicted value of LITLVs when LIs=1 wa 0.76. Using the predicted TLVs the higher risk ones of a large number of tasks can be screened to be further investigated.

• Transactions of Materials Processing
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• v.17 no.8
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• pp.600-606
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• 2008

In closed-die hot forging, a billet is formed in dies such that the flow of metal from the die cavity is restricted. Some parts can be forged in a single set of dies, whilst others, due to shape complexity and material flow limitations, must be shaped in multi sets of dies. The purpose of a performing operation is to distribute the volume of the parts such that material flow in the finisher dies will be sound. This study focused on the design of preforms, flash thickness and land width by theoretical calculation and finite element analysis, to manufacture the super hot forging product, 70MC type piston crown used in marine engine. The optimal design of preforms by the finite element analysis and the design experiment achieves adequate metal distribution without any defects and guarantees the minimum forming load and fully filling of the cavity of the die for producing the large piston crown. The maximum loads obtained by finite element analysis are compared with the results of experiments. The loads of the analysis have good agreements with those of the experiment. Results obtained using DEFORM-2D enable the designer and manufacturer of super hot forging dies to be more efficient in this field.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.4 s.109
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• pp.329-338
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• 2006

The resilient mounts of a diesel engine installed onboard a ship should be designed for both static and dynamic loads. If possible, the resonance frequencies of the six rigid body modes of the installation and the flexible modes of the engine support structure should not lie within the engine operation range. In this paper a design criterion is proposed to evaluate an isolation system which involves the summation of dynamic forces transmitted through the resilient mounts and elastic potential energy index stored in the mounts. A case study is also presented in which a diesel engine generator, which had an elastic foundation and was mounted in a 5500 TEU container vessel, was studied both theoretically and experimentally. The theoretical analysis of the test model was performed by using a single mass 6 degree of freedom system. Actual measurements of mechanical vibration of the engine and its foundation onboard were carried out, which showed the importance of including the flexibility of the engine support structure in the mode.

• Journal of KSNVE
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• v.10 no.5
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• pp.775-782
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• 2000

Being carried out a number of studies for the resilient mounting system of automobile engine than that of the studies for marine engines, many research results for the case of the resilient mounting system of the automobile engine have applied in the analysis for the case of marine engine. However, the size and the power of automobile engines are not only relatively small but also their operating conditions are quite different form those of marine engines. For the analysis of the automobile engine Wavelet shrinkage, misfire condition and unload condition have not been considered. Accordingly , it is not desirable to apply the results obtained form the case of automobile engines to the case of marine engines. In this study , exciting and damping forces working on the marine engine are formulated mathematically in order to apply to the design of a resilient mounting system of engine effectively. futhermore, some mathematical formulation for the analysis of the transmissibility of multi-body system are proposed. A new computer program which is able to calculate the free vibration, the transmissibility and the forced vibration of a resilient mounting system has been developed, As an application of this developed computer program, the dynamic behavior of resilient system with an actual rubber spring for the case of 6-degree-of-freedom system and 36-degree-of-freedom system are evaluated quantitatively.