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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Ocean Engineering and Technology
Journal Basic Information
Journal DOI :
Korean Society of Ocean Engineers
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Volume & Issues
Volume 26, Issue 6 - Dec 2012
Volume 26, Issue 5 - Oct 2012
Volume 26, Issue 4 - Aug 2012
Volume 26, Issue 3 - Jun 2012
Volume 26, Issue 2 - Apr 2012
Volume 26, Issue 1 - Feb 2012
Selecting the target year
Development of Complex Energy Saving Device
Lee, Kwi-Joo ; An, Jung-Sun ;
Journal of Ocean Engineering and Technology, volume 26, issue 3, 2012, Pages 1~5
DOI : 10.5574/KSOE.2012.26.3.001
A complex energy saving device has been developed for middle class vessels. The propulsive performance of the developed device is described through a model test. The pre-swirl stator, which recovers the rotational energy of the propeller slipstream, is a well-known energy saving device for large vessels. The pre-swirl stator for a large vessel is usually cast as a part of the stern frame and has a high cost. The manufacture of a cast stator for an existing vessel is almost impossible. The complex device that was developed can be fitted on astern frame by welding. The model tests show a 4-6% efficiency gain for middle class vessels with the developed appendages compared to those with bare hulls.
Controller Design to Coordinate Autonomous Unmanned Surface and Underwater Vehicles
Lee, Jae-Yong ;
Journal of Ocean Engineering and Technology, volume 26, issue 3, 2012, Pages 6~12
DOI : 10.5574/KSOE.2012.26.3.006
In this paper, addressed is the control problem of generating a formation for a group of unmanned surface and underwater vehicles. The formation control scheme proposed in this work is based on a fusion of theleader-follower and virtual reference approaches. This scheme gives a formation constraint representation that is independent of the number of vehicles in the formation and the resulting control algorithm is scalable. One of the most important features in controller design is the ability of the controller to globally and exponentially stabilize the formation errors defined by the formation constraints. The proposed controller is based on feedback linearization, and the formation errors are shown to be globally and exponentially stable in the sense of Lyapunov.
Analysis of Sound Transmission Characteristics of Multi-complex Panel for Noise Reduction in High Value-added Vessel Cabin
Kwon, Hyun-Wung ; Hong, Suk-Youn ; Kil, Hyun-Gwon ; Kim, Hwa-Muk ; Song, Jee-Hun ;
Journal of Ocean Engineering and Technology, volume 26, issue 3, 2012, Pages 13~19
DOI : 10.5574/KSOE.2012.26.3.013
Recently, as the importance of the interior noise in a ship cabin has risen, ship builders have becomeconcerned about the use of noise reduction panels to reduce cabin noise. The results of previous researches have been based on analytical and experimental methods using simple sandwich panels. However, panel structures are becoming more complex to improve the transmission loss. Thus, researches that analyze the transmission loss of a panel are reaching the limit of study. This paper reports on research that was performed to determine the sound transmission characteristics of multi-complex panels applicable to high value-added vessels. It presents comparisons between analytical methods and experimental results by using a mini-reverberant chamber with components of sound attenuation panels, including the core and surface materials. The sound transmission loss of multi-complex panels are also analyzed in terms of the influences of the inside perforate plates and air gap thickness on the attenuation. Finally, the multi-complex panel with the highest noise attenuation is proposed based on the analysis results and experimental results in mini-reverberant chamber, which wereverified using a real-size reverberant chamber.
Control Allocation and Controller Design for Marine Vessel based on H
Ji, Sang-Won ; Kim, Young-Bok ;
Journal of Ocean Engineering and Technology, volume 26, issue 3, 2012, Pages 20~25
DOI : 10.5574/KSOE.2012.26.3.020
In this paper, the authors propose a new approach to the control problem of marine vessels that are moored or controlled by actuators. The vessel control system is basically based on Dynamic Positioning System (DPS) technology. The main object of this paper is to obtain a more useful control design method for DPS. In this problem, the control allocation is a complication. For this problem, many results have been given and verified by other researchers using a two-step process, with the controller and control allocation design processes carried out individually. In this paper, the authors provide a more sophisticated design solution for this issue. The authors propose a new design method in which the controller design and control allocation problems are considered and solved simultaneously. In other words, the system stability, control performance, and allocation problem are unified by an LMI (linear matrix inequality) based on control theory. The usefulness of the proposed approach is verified by a simulation using a supply vessel model.
Sulfate and Freeze-thaw Resistance Characteristic of Multi-component Cement Concrete Considering Marine Environment
Kim, Myung-Sik ; Beak, Dong-Il ; Kang, Jun-Ho ;
Journal of Ocean Engineering and Technology, volume 26, issue 3, 2012, Pages 26~32
DOI : 10.5574/KSOE.2012.26.3.026
Recently, concrete using multicomponent blended cement has been required to increase the freeze-thaw and sulfate resistances of concrete structures exposed to a marine environment. Thus, the purpose of this study was to propose the use of concrete containing multicomponent blended cement as one of the alternatives for concrete structures exposed to a marine environment. For this purpose, batches of concrete containing ordinary portland cement (OPC), binary blended cement (OPC-G, G: ground granulated blast slag), ternary blended cement (OPC-GF, F: fly ash), and quaternary blended cement (OPC-GFM, M: mata-kaolin) were made using a water-binder ratio of 50%. Then, the durability levels, including thesulfate and freeze-thaw resistances, were estimated for concrete samples containing OPC, OPC-G, OPC-GF, and OPC-GFM. It was observed from the tests that the durability levels of the concrete samples containing OPC-G and OPC-GF were found to be much better than that of the concrete containing OPC. The optimum mixing proportions were a40% replacement ratio of ground granulated blast slag for the binary blended cement and a30% replacement ratio of ground granulated blast slag and 10% fly ash for the ternary blended cement.
Experimental Study of Shape Parameter of Land-based OWC Wave Energy Converter
Koo, Weon-Cheol ; Kwon, Jin-Sung ; Kim, Jun-Dong ; Kim, Sung-Jae ; Kim, Min-Woo ; Choi, Mun-Kwan ;
Journal of Ocean Engineering and Technology, volume 26, issue 3, 2012, Pages 33~38
DOI : 10.5574/KSOE.2012.26.3.033
The aim of this experimental study was to analyze the effect of the shape parameters and chamber pressure of a land-based oscillating water column (OWC) in regular incident waves. The magnitude of the free surface elevations inside the chamber was measured in a two-dimensional wave tank for various chamber skirt drafts and bottom slope angles. The surface elevations were also measured under both open chamber and partially open chamber conditions. From these measurements, the optimum shape of the OWC device could be predicted for the maximum wave energy conversion efficiency. It was found that the resonance frequency of the OWC system associated with incident waves moved toward the long wave region with increments of the draft of the chamber skirt and bottom slope. The behavior of the free surface elevation inside the chamber was also found to be dependent on the chamber pressure.
Strength Characteristic of Waste Fishing Net-added Lightweight Soil Considering Glue Treatment
Yun, Dae-Ho ; Kim, Yun-Tae ;
Journal of Ocean Engineering and Technology, volume 26, issue 3, 2012, Pages 39~45
DOI : 10.5574/KSOE.2012.26.3.039
This paper investigates the strength characteristics and stress-strain behaviors of waste fishing net (WFN)-added lightweight soil. The lightweight soil, which consisted of dredged soil, crumb rubber, and cement, was reinforced with WFN in order to increase its shear strength. Glue treated WFN was also added to lightweight soil to improve the interlocking between the soil mixture and WFN. Three kinds of test specimens were prepared: unreinforced lightweight soil, reinforced lightweight soil without glue treatment, and reinforced lightweight soil with glue treatment. Several series of laboratory tests were carried out, including flow value tests, unconfined compression tests, and SEM analyses. From the experimental results, it was found that the peak strength of the reinforced lightweight soil with glue treatment was increased by the increased interlocking between the soil mixture and WFN, which was induced from the bonding effect. The stress-strain relation of the reinforced lightweight soil, irrespective of the glue treatment, showed a more ductile behavior than that of the unreinforced lightweight soil.
Parametric Study on Explosion Impact Response Characteristics of Offshore Installation's Corrugated Blast Wall
Kim, Bong-Ju ; Kim, Byung-Hoon ; Sohn, Jung-Min ; Paik, Jeom-Kee ; Seo, Jung-Kwan ;
Journal of Ocean Engineering and Technology, volume 26, issue 3, 2012, Pages 46~54
DOI : 10.5574/KSOE.2012.26.3.046
More than 70% of the accidents that occur on offshore installations stem from hydrocarbon explosions and fires, which, because they involve blast effects and heat, are extremely hazardous and have serious consequences in terms of human health, structural safety, and the surrounding environment. Blast barriers are integral structures in a typical offshore topside module to protect personnel and safety critical equipment by preventing the escalation of events caused by hydrocarbon explosions. Many researchers have shown the adequacy of the simple design tool commonly used by the offshore industry for the analysis and design of blast walls. However, limited information is available for corrugated blast wall design with explosion impact response characteristics. Therefore, this paper presents a parametric study on the explosion impact response characteristics of an offshore installation's stainless steel corrugated blast wall. This paperalso investigates and recommends design parameters for the structural design of a corrugated blast wall based on a nonlinear structural analysis of experiential results.
Effect of Deformation Temperature on Mechanical Properties of High Manganese Austenitic Stainless Steel
Kang, Chang-Yong ; Hur, Tae-Young ; Kim, Young-Hwa ; Koo, Cha-Jin ; Han, Hyun-Sung ; Lee, Sang-Hee ;
Journal of Ocean Engineering and Technology, volume 26, issue 3, 2012, Pages 55~60
DOI : 10.5574/KSOE.2012.26.3.055
This study was carried out to investigate the effect of the deformation temperature in high manganese austenitic stainless steel.
'-martensite was formed with a specific direction by deformation. The volume fraction of the deformation induced martensite was increased by increasing the degree of deformation and decreasing the deformation temperature. With the increase in the deformation, the hardness and tensile strength were increased, while the elongation was rapidly decreased at the initial stage of the deformation, and then gradually decreased. The hardness and tensile strength were increased and the elongation was decreased with adecrease in the deformation temperature. The hardness and tensile strength were strongly controlled by the volume fraction of martensite, but the elongation was controlled by the transformation behavior of the deformation induced martensite.
Multi-phase Flow Velocity Measurement Technique using Shadow Graphic Images
Ryu, Yong-Uk ; Jung, Kwang-Hyo ;
Journal of Ocean Engineering and Technology, volume 26, issue 3, 2012, Pages 61~65
DOI : 10.5574/KSOE.2012.26.3.061
Air-water flow measurements are of importance for the coastal and ocean engineering fields. Although kinematic investigations of the multi-phase flows have been conducted for long time, velocity measurements still are concerned with many researchers and engineers in coastal and ocean areas. In the present study, an imaging technique using shadowgraphy and fiber optic probe for velocity measurements of air bubbles is introduced. The shadow graphy image technique is modified from the typical image velocimetry methods, and optical fibers are used for the well-known intrusive coupled phase-detection probe system. Since the imaging technique is a non-intrusive optical method from the air, it is usually applied for 2D flows. On the other hand, the double fiber optic probes touch flows regardless of flow patterns. The results of the flow measurements by both methods are compared and discussed. The methods are also applied to the measurements of overtopping flows by a breaking wave over the structure fixed on the free surface.