• International Journal of Ocean System Engineering
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• v.1 no.4
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• pp.192-197
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• 2011

This paper describes the mathematical modeling, control algorithm, system design, hardware implementation and experimental test of a Manta-type Unmanned Underwater Vehicle (MUUV). The vehicle has one thruster for longitudinal propulsion, one rudder for heading angle control and two elevators for depth control. It is equipped with a pressure sensor for measuring water depth and Doppler Velocity Log for measuring position and angle. The vehicle is controlled by an on-board PC, which runs with the Windows XP operating system. The dynamic model of 6DOF is derived including the hydrodynamic forces and moments acting on the vehicle, while the hydrodynamic coefficients related to the forces and moments are obtained from experiments or estimated numerically. We also utilized the values obtained from PMM (Planar Motion Mechanism) tests found in the previous publications for numerical simulations. Various controllers such as PID, Sliding mode, Fuzzy and $H{\infty}$ are designed for depth and heading angle control in order to compare the performance of each controller based on simulation. In addition, experimental tests are carried out in a towing tank for depth keeping and heading angle tracking.

• Carbon letters
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• v.16 no.4
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• pp.241-246
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• 2015

Rapid industrial development in recent times has increased the demand for light-weight materials with high strength and structural integrity. In this context, carbon fiber-reinforced plastic (CFRP) composite materials are being extensively used. However, laminated CFRPs develop faults during impact because CFRPs are composed of mixed carbon fiber and epoxy. Moreover, their fracturing behavior is very complicated and difficult to interpret. In this paper, the effect of the direction of lamination in CFRP on the absorbed impact energy and impact strength were evaluated, including symmetric ply (0°/0°, −15°/+15°, −30°/+30°, −45°/+45°, and −90°/+90°) and asymmetric ply (0°/15°, 0°/30°, 0°/45°, and 0°/90°), through drop-weight impact tests. Further, the thermal properties of the specimens were measured using an infrared camera. Correlations between the absorbed impact energy, impact strength, and thermal properties as determined by the drop-weight impact tests were analyzed. These analyses revealed that the absorbed impact energy of the specimens with asymmetric laminated angles was greater than that of the specimens with symmetric laminated angles. In addition, the asymmetry ply absorbed more impact energy than the symmetric ply. Finally, the absorbed impact energy was inversely proportional to the thermal characteristics of the specimens.

• Journal of Families and Better Life
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• v.25 no.1 s.85
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• pp.29-43
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• 2007

Effectiveness of Long-term Group-counseling in Improving Emotional Intelligence and Prosocial Behavior in Preschooler The purpose of this study was to assess the effectiveness of long-term group-counseling in preventing children's maladjustment at school. for this study, six children were selected for an experimental group and another six for a control group. They were tested using the Emotional Intelligence Rating System and the Prosocial Behavior Skill Situations Measure for Preschool Level. In addition to quantitative analysis, a qualitative analysis was conducted to examine group processes and changes in each child. The experimental group participated insocio-drama, group art therapy, and game play therapy whereas the control group did not receive any treatment. In order to examine the impact of the intervention, pre-program tests and post-program tests were conducted. The results were as follows. First, the children's emotional intelligence was improved with group counseling. There was a significant difference in emotional intelligence between the experimental and the control groups. Second, children's prosocial behavior ability alsoimproved. There was a significant difference in social ability between the experimental and the control groups.

• Journal of the Korean Geosynthetics Society
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• v.10 no.3
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• pp.9-18
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• 2011

This paper presents shear characteristics of a ground improved by sand piles. The sand piles have different length and diameter depending on the depth of a clayey layer. A series of CU triaxial compression tests are carried out on specimens covered with/without soft material which is similar to geotextile. The results show that the shear strength and stress ration increase as the length and the diameter of the sand pile increase. In addition, covering the specimen with the soft material appears to affect those characteristics as well. The increase of cohesion seems to be more remarkable compared to internal frictional angle.

• Journal of the Korean Geosynthetics Society
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• v.8 no.2
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• pp.41-46
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• 2009

In this paper, a series of model tests were performed in laboratory to evaluate promoting consolidation of compaction pile methods for soft ground improvement. For the model tests, composite soil samples that have 10% replacement area ratio were prepared by using sand, gravel, and sandy gravel for the materials of compaction piles. After loading to each composite soil sample, the excess pore pressure dissipation and settlement were investigated. In addition, the behavior of clay mixed with each compaction pile was also monitored at the end of consolidation to evaluate clogging phenomenon. As a test result, the effects for decreasing settlement and promoting consolidation by GCP were prominent, and the mixed clay was not monitored in all of the three compaction piles.

• Journal of Korea Foundry Society
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• v.37 no.2
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• pp.31-37
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• 2017

A new form of austenitic heat-resistant ductile iron was developed and its microstructures and elevated temperature properties were compared to those of Ductile Ni-Resist D5S. According to JMatPro calculations, it was predicted that Mo-rich carbides would be crystallized before the eutectic reaction starts in the developed alloy. At the austenite cell boundaries of the developed alloy, both Mo-rich carbides and Cr-rich carbides were found. In addition, Ni-silicides were found adjacent to Cr-rich carbides in D5S specimen and were identified as $Ni_2Si$. The developed alloy also had greater yield strength and lower tensile strength levels with less elongation due to the dissolution of Mo atoms into the austenite matrix and the precipitation of Mo-rich carbides. From the results of elevated temperature tensile tests and stress-rupture tests, it was found that the developed alloy had elevated temperature properties superior to those of D5S. This was due to the pinning effect of the dissolved Mo atoms in the austenite matrix.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.9
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• pp.527-536
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• 2020

International business research presents a broad consensus on the importance of dynamic capabilities in the internationalization of SMEs. However, there is a lack of research on assessing the impact of dynamic capabilities and the level of SMEs' internationalization operating in a turbulent and dynamic business environment. This study examines the impact of environmental dynamism and three sets of dynamic capabilities, namely, sensing, seizing, and reconfiguring capabilities on internationalized SMEs' geographic scope. In addition, this research examines the association between internationalized SMEs' characteristics: SME's age, size, and SME owner/manager's international experience and SMEs' geographic scope. This study used a quantitative research and employed survey questionnaires to collect data from 305 internationalized Malaysian manufacturing SMEs. Anova tests and Chi Square tests were employed to analyze data collected from respondents using SPSS. Research findings revealed that environmental dynamism and dynamic capabilities have a significant impact on internationalized SMEs' geographic scope, however, none of the internationalized SMEs' characteristics had a significant relationship with their geographic scope. The result of this research suggest internationalized SMEs owner/managers need to possess sensing, seizing and reconfiguring capabilities, and monitor business environmental dynamism to increase their geographic scope. This paper ends with drawing a set of concluding remarks and recommendations.

• Journal of the Korean institute of surface engineering
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• v.45 no.1
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• pp.25-30
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• 2012

The galvanostatic tests for corrosion protection are conducted at various applied current densities during 93,600 sec, and evaluated in terms of the variations in current density with time and in the potential at the applied current density. In addition, the corrosion damage depth is analyzed with 3D analysis optical microscope after galvanostatic tests. In this study, it was investigated to decide condition of the corrosion protection gavalnostatic method for Cu-Al alloy that has an excellent corrosion resistance. In the galvanostatic test under the cavitation environment, the energy was reflected or cancelled out by the collision with the oxygen gas generated by the oxygen reduction action. The surface observation showed neither the cavitation damage nor the electrochemical damage in the current density over 0.01 $A/cm^2$ in the dynamic state under the cavitation environment.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.3 s.14
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• pp.25-31
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• 2004

Rail road slope can be fatted because of existence of unexpected soft subsoil. Purpose of this study is verifying the cause of rail road slope failure and determination of soil strength for remedy. Drilling some boreholes, cone penetration test and field vane test were executed in order to find out the cause of slope failure. In addition, laboratory test was conducted in order to determine soil strength of soft soil sampled as undisturbed state. As a result of both the in-situ and the laboratory tests, the cause of slope failure is thought to be propagation of failure zone by progressive rupture of overconsolidated clay Soft soil strength was determined through back analysis of the failed slope.

• Clinical and Experimental Pediatrics
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• v.63 no.2
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• pp.52-55
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• 2020

Background: Immunomodulatory properties of interferon (IFN) have been documented. It may induce autoimmune diseases such as autoimmune thyroiditis with hypo- or hyperthyroidism. In addition, it may impair thyroid hormone synthesis through affecting iodide organification in thyroid gland. Purpose: The aim of this study was to describe thyroid function tests disturbances in children with chronic hepatitis C (CHC) receiving pegylated interferon-alpha (PEG IFN-α) plus ribavirin. Methods: Fifty children with CHC virus infection who received combined pegylated interferon-alpha with ribavirin were selected. Other 50 apparently healthy children of matched age and sex (considered as control group) were selected. All children (100) were subject to liver function tests, virological studies, and follow-up of thyroid function test during and after the treatment course. Results: Our study showed that 28% of children received combined PEG IFN-α plus ribavirin showed subclinical hypothyroidism. After 24 weeks treatment with combined therapy of IFN plus ribavirin, the mean level of thyroid stimulating hormone (TSH) was 3.23±88 mU/mL, while TSH was 1.16±0.77 mU/mL before starting treatment. On the other hand, mean TSH was 1.09±0.92 mU/mL in normal control group. Conclusion: This study revealed an association between subclinical thyroid dysfunction and treatment with IFN-alpha and ribavirin in children. Further studies on larger number of patients and longer follow-up duration are recommended for further confirmation.