• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.4
• /
• pp.567-576
• /
• 2022

Seafarers are exposed to various unpredictable maritime risks due to the spatial specificity of the working environment of the sea; thus, sufficient compensation for injured crewmembers is needed. However, Korea does not provide such compensation. Therefore, this study attempted to examine the Maritime Labor Act and the Industrial Accident Insurance Act of Germany, an advanced European social insurance country, and derive implications compared to Korea. First, we investigated how compensations are managed by a public institution in Germany and by shipowners in Korea. Second, regarding the contents of accident compensation, Germany does not only provide continuous treatment and care through various support systems, but also operates various programs to enable a return to ship work. In contrast, Korea has a temporary compensation system that allows shipowners to avoid liability for accident compensation, which is disadvantageous to shipwrecked seafarers. Finally, in Germany, workers' compensation insurance is public, judged considering the origin of work, whereas in Korea, it is determined by shipowners or insurance companies. Therefore, it is necessary to establish a public institution in charge of crew accident compensation to ensure proper compensation for crewmembers in Korea and to improve the Seafarers Act or system to provide compensation for additional medical care, disability pension, and rehabilitation benefits.

• The Journal of Korean Academy of Prosthodontics
• /
• v.60 no.1
• /
• pp.19-28
• /
• 2022

In removable partial dentures, abutment teeth are essential for support, maintenance, and stability of partial dentures, and are an important factor in the fabrication of functional dentures. If the number of periodontally sound abutments is sufficient and they are located on both sides, it will be easy to manufacture functional dentures with good support, maintenance, and stability. But on the contrary, if the number of teeth is insufficient or if they are located on one side, it is biomechanically disadvantageous and relatively difficult to make functional denture. On the other hand, recently, implant-supported removable dentures, which reinforce the three elements of maintenance, support, and stability by using implant surveyed crown, have been frequently selected as treatment plans. In particular, by adding an implant surveyed crown when only a small number of residual teeth remain, mastication efficiency, esthetics, patient comfort, and pronunciation can be improved. In this case, bilateral posterior extension partial denture was fabricated using implant surveyed crown as abutments by placing implants in the premolars area opposite to the residual tooth unilaterally in the mandible. As a result, the asymmetry of the abutment was resolved, and the maintenance and stability of the denture was achieved.

• Journal of Korea Entertainment Industry Association
• /
• v.14 no.7
• /
• pp.477-485
• /
• 2020

This study is a random allocation similar experimental study to compare and analyze the difference in BVM (Bag-Valve-Mask) ventilation volume according to the characteristics of the rescuer's hand and the type of mask using a standardized mannequin. To this end, the Basic Life Resuscitation Education Center of D University in gwangju. Recruiting 39 students who have completed the basic resuscitation course for emergency medical personnel and the Korean-style specialized cardiac rescue course, In addition to measuring the physical characteristics of the hand, the average amount of ventilation per minute using a bag-mask was measured and analyzed. As a result, the type of mask that was not most affected by the characteristics of the hand and provided adequate Minute Ventilation was the soft type (tube, silicone) mask. On the other hard (tube, silicone) masks were found to be unsuitable for general use as they were greatly affected by the characteristics of workers' hands. COVID-19 is currently increasing the risk of transmission to paramedics and patients. Considering this situation, the universal use of a semi-permanent hard-type mask, which is disadvantageous not only for preventing infection but also for proper ventilation, should be avoided. In addition to the ease of use, it should be actively utilized in the field by supplying a soft type mask that can provide stable ventilation even with 'predominance recognition' and proper ventilation.

• Journal of the Korean Geotechnical Society
• /
• v.24 no.6
• /
• pp.45-55
• /
• 2008

CFRD (Concrete Faced Rockfill Dam) has been world-widely constructed due to a lot of advantages which it has compared with rockfill dam and recently, sand/gravel materials, Instead of crushed rock materials, are also utilized as a main rockfill material to overcome geological and environmental problems. In Korea, two dams using sand/gravel materials as a main fill material were designed and are being constructed. In this research, the strength and deformation characteristics of the rockfill and sand/gravel materials taken from 2 dam sites were tested by using a laboratory large triaxial testing equipment for a total of 7 cases. From the results of large triaxial and compaction tests, it was observed that two kinds of materials show a little different compaction, shear strenght and deformation characteristics. It could be expected that the shear strength of sand/gravel material was not disadvantageous compared with that of rockfill materials, however, there was some difference between two materials with respect to behavior characteristics. On the other hand, smaller displacements were observed from numerical analysis based on the data from a large triaxial test when the sand/gravel is used as a main fill material compared with the case when the crushed rock material is used as a main fill material. Finally, in spite of a little different shear strength and behavior characteristic between two materials, it was concluded that it will not lead to a significant problem when the sand/gravel material is used as a main rockfill material.

• Composites Research
• /
• v.20 no.4
• /
• pp.31-41
• /
• 2007

Dome shape design methods of Filament Winding (FW) composite pressure vessel, which can suggest various dome contour according to the external loading conditions, were investigated analytically and numerically. The performance indices(PV/W) of the pressure vessels with same cylinder radius and boss opening but different dome shape were evaluated by finite element analysis under the internal pressure loading condition. The analysis results showed that as the dome shape becomes flat, the performance index decreases significantly due to the reduced burst pressure. Especially, for the case of the high value of the parameter ro, the ratio between the radii of the cylinder part and the boss opening, the flat dome is disadvantageous in the aspect of the weight reduction, and additional reinforcing dome design technique should be required to increase the burst pressure. For example, above ro=0.54 condition, the dome shape change according to the loading condition could cause the low burst pressure and increase of composite weight in dome region and is not recommendable except for the special case that maximum inner volume or sufficient space between skirt and dome is the primary design objective. However, at ro=0.35, the dome shape change brings not so significant differences in the performance of FW vessel.

• Journal of the Korean institute of surface engineering
• /
• v.56 no.3
• /
• pp.192-200
• /
• 2023

Graphene, a two-dimensional material, has shown great potential in a variety of applications including microelectronics, optoelectronics, and graphene-based batteries due to its excellent electronic conductivity. However, the production of large-area, high-quality graphene remains a challenge. In this study, we investigated graphene growth on electrolytic copper foil using thermochemical vapor deposition (TCVD) to achieve a similar level of quality to the cold-rolled copper substrate at a lower cost. The combined effects of pre-annealing time, graphenized temperature, and partial pressure of hydrogen on graphene coverage and domain size were analyzed and correlated with the roughness and crystallographic texture of the copper substrate. Our results show that controlling the crystallographic texture of copper substrates through annealing is an effective way to improve graphene growth properties, which will potentially lead to more efficient and cost-effective graphene production. At a hydrogen partial pressure that is disadvantageous in graphene growth, electrolytic copper had an average size of 8.039 ㎛², whereas rolled copper had a size of 19.092 ㎛², which was a large difference of 42.1% compared to rolled copper. However, at the proper hydrogen partial pressure, electrolytic copper had an average size of 30.279 ㎛² and rolled copper had a size of 32.378 ㎛², showing a much smaller difference of 93.5% than before. This observation suggests this potentially leads the way for more efficient and cost-effective graphene production.

• Korean Journal of Optics and Photonics
• /
• v.34 no.4
• /
• pp.139-150
• /
• 2023

Despite various light detection and ranging (LiDAR) architectures, it is very difficult to achieve long-range detection and high resolution in both vertical and horizontal directions with a wide field of view (FOV). The scanning architecture is advantageous for high-performance LiDAR that can attain long-range detection and high resolution for vertical and horizontal directions. However, a large-area photodetector (PD), which is disadvantageous for detection speed, is essentially required to secure the wide FOV. Thus we propose a PD based on the static unitary detector (STUD) technique that can operate multiple small-area PDs as a single large-area PD at a high speed. The InP/InGaAs STUD PIN-PD proposed in this paper is fabricated in various types, ranging from 1,256 ㎛×949 ㎛ using 32 small-area PDs of 1,256 ㎛×19 ㎛. In addition, we measure and analyze the noise and signal characteristics of the LiDAR receiving board, as well as the performance and sensitivity of various types of STUD PDs. Finally, the LiDAR receiving board utilizing the STUD PD is applied to a 3D scanning LiDAR prototype that uses a 1.5-㎛ master oscillator power amplifier laser. This LiDAR precisely detects long-range objects over 50 m away, and acquires high-resolution 3D images of 320 pixels×240 pixels with a diagonal FOV of 32.6 degrees simultaneously.

• Economic Analysis
• /
• v.25 no.4
• /
• pp.58-108
• /
• 2019

This paper analyzes the determining factors in the unemployment rate among young people in their 20s by studying data from 30 OECD countries between 2000 and 2017. It identifies reasons why Korea has a higher youth unemployment rate than Japan, and assesses what implications Japan's youth unemployment measures could have on Korea. The study highlights the variables that have meaningful impacts on youth unemployment. They include the unemployment rate among the working-age population, the percentage of each age bracket in the overall population, the GDP growth rate, the percentage of wage laborers in each age group, the percentage of elderly people, and the percentage of part-time workers. This paper also finds that a decline in the youth population, especially among people in their 20s, does not help to address the issue of youth unemployment. Secondly, this paper explains the additional factors behind Korea's higher youth unemployment rates. One is Korea's disadvantageous employment environment, compared to that in Japan, in terms of wage earnings. Other factors include the existence of fewer decent corporate jobs than in Japan, and wide disparities in wages between large and small corporate jobs. Therefore, while making efforts to resolve long-term and structural problems, it is necessary to actively promote policy measures to solve short-term mismatch problems of youth employment by referring to Japanese policy examples.

• Journal of The Korean Association For Science Education
• /
• v.28 no.1
• /
• pp.75-88
• /
• 2008

The purpose of this study was to understand the factors affecting interactions as well as the students' learning process in small group activities. For this purpose, the changes and characteristics of students' interactions in scientific inquiry experiments were analyzed. This study focused on 2 homogeneous small groups of eighth graders. Students were involved in 13 inquiry experiments for one year and students' interactions in each experiments were observed and recorded using video/audio and the data recorded were transcribed. The analysis of data was based on the method of making a note by looking on and listening to the data repeatedly. Changes in the interactions of the two homogeneous groups differ remarkably. In small group A, owing to the conflicts of students' emotions, learning through social interactions became to be impossible. On the other hand, the interactions in small group B became more active. It seems that this changes are affected largely by the existence of peers who are able to mediate different opinions or feelings among group members. In general, middle school students were poor at receiving peers' opinion, cared a lot about writing reports. The less able students tended to be placed at a disadvantageous position in experiment lessons emphasizing social interactions. Four factors that affected the change of interactions were identified: Is the aim of experiments the understanding or completion of report? Is there any attitude towards peers' suggestions? Is there a disposition to care about peers? Is there any peer to mediate on peers' opinions or feelings? Educational implications of the progression of activities emphasizing interactions and the organization of grouping were drawn.

• Ecology and Resilient Infrastructure
• /
• v.11 no.2
• /
• pp.43-54
• /
• 2024

Recently, most of the rivers in Korea are experiencing various problems in dimension and river environment, such as expansion of stable area where disturbance does not occur during flood, increase of excessive trees in river channel, fixation of river channel, reduction of sand bar. When the soil supplied by the flood is deposited in the river, the plant is settled in the formed terrain, and when another disturbance of the scale that does not erode there occurs after the plant is settled, the river gradually grows and the vegetation zone is formed there. In particular, in terms of river management, river forestation and river aggradation are objects that must be managed because they are disadvantageous in terms of flood control by lowering the flow rate and raising the water level. Therefore, in this study, the area of vegetation occupied by the year of sandbar was analyzed in the process of river aggradation in Jang-Hang wetland. In addition, the correlation between the growth of Jang-Hang wetland was analyzed through the analysis of the flow rate and the flooding frequency that directly affect the growth of Jang-Hang wetland. Through this, the management plan of Jang-Hang wetland, which is registered in Ramsar Wetland but has been river forestation and is undergoing river aggradation, was proposed.