• Korean journal of communication and information
• /
• v.48
• /
• pp.257-279
• /
• 2009

The purpose of the current study is to examine the structural relationship between communication competence and self-presentation through motivational perspectives. The present study hypothesized structural model to examine the effects of autonomy, relatedness, and life satisfaction along with communication competence on the self-presentation. We investigated how these effects were influenced by differences in the structural relationships of males and females. The data with the sample of 361 college students adequately fit to the hypothesized model. Through latent mean analysis, gender differences of the constructs were examined. The female students appeared to have higher levels of relatedness than the male students. The results showed that autonomy and relatedness are important factors to self-presentation mediating communication competence.

• Journal of Ocean Engineering and Technology
• /
• v.19 no.2 s.63
• /
• pp.67-73
• /
• 2005

This paper describes depth, heading and speed control of an underwater vehicle that has four stern thrusters of which forces are coupled in the diving and, steering motion, as well as the speed of the vehicle. The optimal linear quadratic controller is designed based on a linearized- state space model, developed by combining the dynamic equations of speed, steering and diving motion. The designed controller gives provides an optimal thrust distribution, minimizing the given performance index to control speed, depth and heading simultaneously. To validate the performance of the controller, a simulation and tank-test are carried out with DUSAUV (Dual Use Semi-Autonomous Underwater Vehicle), developed by KORDI as a test-bed for testing new underwater technologies. Optimal gains of the controller are tuned, using a computer simulation environment with a nonlinear 6-DOF numerical DUSAUV model, developed by PMM (Planner Motion Mechanism) test. To verify the performance of the presented controller in experiment, a tank-test with DUSAUV is carried out in the ocean engineering basin in KORDI. The experimental results are also compared with the simulation results to investigate the accordance of the numerical and the real mode.

• Journal of Ocean Engineering and Technology
• /
• v.32 no.4
• /
• pp.287-295
• /
• 2018

This paper presents the results of an exploration of the ferromanganese crusts of Western Pacific Seamount registered by the Korean government. This area has been surveyed with a deep-sea camera and crust samples have been acquired by deep-sea dredging since 2013. On October 18-19, 2017, a united research team from KIOST and KRISO explored two blocks, OSM11 and OSM07, on the seamount using Hemire ROV. A precise survey was conducted on the ferromanganese crusts and sediments covering the slope/top of OSM11 and the middle flat area of OSM07. Rock samples were collected with precise positioning, and HD videos were recorded for 7 hours. This paper discusses the technical issues of this exploration in terms of (1) how to deal with an emergency situation during an electric power blackout, (2) the improvement of the thruster power by adding cooling plugs to the housings of the thruster amplifiers, (3) the relative motion of the depressor by changing the fixing method of the cable terminator, which affects the service life of the cable, (4) a sampling technique for the steep slope of the seamount, (5) integrated navigation under a USBL blackout, and (6) a 3-dimensional image mosaic for visualizing the distribution state of the crusts.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.1
• /
• pp.21-28
• /
• 2010

This paper describes the mathematical model and controller design for Manta-type Unmanned Underwater Test Vehicle (MUUTV) with 6 DOF nonlinear dynamic equations. The mathematical model contains hydrodynamic forces and moments expressed in terms of a set of hydrodynamic coefficients which were obtained through the PMM (Planar Motion Mechanism) test. Based on the 6 DOF dynamic equations, numerical simulations have been performed to analyze the dynamic performances of the MUUTV. In addition, using the mathematical model PID and sliding mode controller are constructed for the diving and steering maneuver. Simulation results show that the control performances of the MUUTV and compared with these of NPS (Naval Postgraduate School) AUV II.

• Ocean and Polar Research
• /
• v.36 no.3
• /
• pp.277-288
• /
• 2014

The Korean government is considering the implementation of a project to develop a deep-sea human-operated vehicle (HOV) to improve the level of deep-sea research. Information on the scientific benefits from the project is urgently needed in order to come to a decision about whether to implement the project. This paper measures the conservation value of developing nine attributes associated with HOV by using the choice experiment (CE). A survey of about 356 experts was undertaken and 132 experts completely responded to the survey. To deal with the CE data from the survey, we employed a multinomial logit model. All the coefficient estimates are statistically significant and consistent with prior expectations. Therefore, we can judge that the respondents' works required in the CE survey were within their cognitive abilities and they reported responsible and significant values. Each marginal willingness to pay for each attribute associated with the HOV is statistically significant and provides good information on the scientific values with regard to developing the HOV. The results can be utilized in evaluating and planning several alternatives related to developing the HOV.

• The Korean Journal of Community Living Science
• /
• v.28 no.2
• /
• pp.203-215
• /
• 2017

This study was carried out to compare the major nutrient components and antioxidant activities of Stachys sieboldii Miq leaf and root powders. For proximate compositions, crude protein and crude fat contents of leaf powder were higher than those of root powder, whereas contents of crude ash and carbohydrates were lower in leaf powder. The content of glutamic acid was greater in amino acids of leaf and root powders, and contents of total amino acids and essential amino acids were higher in leaf powder compared with root powder. Root powder contained a higher level of total unsaturated fatty acids than leaf powder. Total contents of organic acids were higher in leaf powder; tartaric acid was the major organic acid in leaf powder, and malic acid was the major organic acid in root powder. The content of vitamin A was higher in leaf powder than in root powder. However, vitamin E content was higher in root powder than in leaf powder. Total mineral contents of leaf powder were higher than those of root powder, and mineral contents of leaf and root powders were in the order of K>Ca>Mg. Extract yields of leaf and root powders were 27.21% and 58.51%, respectively. Total polyphenols and total flavonoids of leaf extract were 236.35 mg/g and 1.90 mg/g, respectively, which were higher than those of root extract. The $IC_{50}$ values of leaf and root ethanol extracts based on DPPH hydroxyl scavenging were 0.69 mg/mL and 5934.31 mg/mL, respectively, and antioxidative activities of ethanol extracts from all Stachys sieboldii Miq parts dose-dependently increased. These results suggest that Stachys sieboldii Miq can be recommended as an edible functional food material.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.36 no.5
• /
• pp.528-534
• /
• 2003

The 2-D hydraulic experimental results for the submerged rubble-mound structure, we have been concerned with the slability/function characteristics of the structures by the effects of wave force, scour/deposition at the toe and the wave transmission ratio at the lee-side sea. So, to investigate the variation characteristics of the wave transmission ratio which depended on a geometrical structure of the submerged breakwater profiles, the critical conditions for the depth of submergence and crest width were obviously presented. In summary, the results lead us to the conclusion that the wave control capabilities of submerged breakwaters by the variation of the submergence depth is higher than about 4 times the degree at the efficiency than the that of crest width. The destruction of the covering block at the crest generated at the region which was located between the maximum and minimum damage curve, and it's maximum damage/failure station from the toe of the structure was $0.2\;L_s.$ As the wave transmission coefficient and the slope of the structure increase, the damage/failure ratio and the maximum scour depth at the toe was extended, respectively. When the maximum scour depth happened, the destruction of the covering block which was located at the toe generated at the front of the submerged rubble-mound breakwater. Finally, it was found from the results that the optimization of the structure may be obtained by the efficient decision of the submergence depth and crest width in the permissible range of the wave transmission ratio.

• Water for future
• /
• v.27 no.1
• /
• pp.123-131
• /
• 1994

A plunge pool is often employed as an energy-dissipating device at the end of a spillway or a pipe culvert. A jet from spillways or pipes frequently generates a scour hole which threatens the stability of the hydraulic structure. Existing scour prediction formulas of plunge pool of spillways or pipe culverts give a wide range of scour depths, and it is, therefore, difficult to accurately predict those scour depths. In this study, a new experimental method and new scour prediction formulas under submerged circular jet for large bed materials with shallow tailwater depths were developed. A major variale, which was not used in previous scour prediction equations, was the ratio of jet size to bed material size. In this study, jet momentum acting on a bed particle and jet diffustion theory were employed to derive scour prediction formulas. Four theoretical formulas were suggested for the two regions of jet diffusion, i.e., the region of flow establishment and the region of established flow. The semi-theoretically developed scour prediction formulas showed close agreement with laboratory experiments performed on a movable bed made of large spherical particles.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.213-216
• /
• 2007

The paper deals with a approach to underwater acoustic based Ad-hoc communication, which allows major design strategies for Media Access Control (MAC) within a group of the autonomous underwater vehicles(AUV). The proposed MAC aims at deploying AUV-centric star topology, which minimizes overhead of sensor nodes and improves energy-efficiency. Furthermore, that is also well under long and unknown propagation delays of the underwater acoustic medium. The implemented MAC protocol makes it easier to achieve frame synchronization than TDMA due to deploying localized schedule time, in addition to saving energy consumption by letting nodes sleep. It is also superior to MACA and MACAW in terms of propagation delay. This scalable centralized protocol has the potential to serve as a primer for development of MAC protocol for future underwater acoustic based ad-hoc networks.

• Science of Emotion and Sensibility
• /
• v.21 no.1
• /
• pp.129-142
• /
• 2018

We spend about one-third of our life sleeping. Although the influence of sleep on various cognitive and affective functioning is recognized, relatively less is known about its consequences on interpersonal relationships. The present study examines whether sleep contributes to adolescent's peer intimacy; specifically, given the role of sleep in memory consolidation, it was assumed that a good sleep will enhance social relationships by positively refurbishing memories of social episodes. As predicted, young teenagers' sleep quality predicted increased peer intimacy, partly through the positive memory of social events, in a sample of middle school (Study 1) as well as high school participants (Study 2). To investigate the causal link, in Study 2, memory recollections were repeatedly measured for a week. Sleep quality during the week predicted how social, but not non-social episodes were positively remembered. The function and importance of sleep quality are discussed in the context of interpersonal relationships.