• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.334-342
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• 2021

In Korea, the training is performed through independent environments without interoperability among L-V-C systems. In the L system, training for large units is limited due to civil complaints at the training grounds and road restrictions. The V system is insufficient in training related to tactical training, and the C system lacks practicality due to a lack of combat friction elements. To achieve synchronicity and integration training between upper and lower units, it is necessary to establish a system to ensure integrated training for each unit by interoperating the currently operating L, V, and C systems. The interoperability between the C-C system supports Korea-US Combined Exercise. On the other hand, the actual development of the training system through the interoperability of L, V, and C has not been made. Although efforts are being made to establish the L, V, and C system centering on the Army, the joint composite battlefield and LVC integrated architecture technology are not yet secured. Therefore, this paper proposes a new plan for the future training system by designing and implementing the LVC integrated architecture technology, which is the core technology that can build the L-V-C interoperability training system. In conclusion, a division-level L-V-C interoperability training system can be established in the future by securing the LVC integrated architecture technology.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.15-21
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• 2021

Electrically powered airplanes can reduce CO₂ emissions from fossil fuel use and reduce airplane costs in the long run through efficient energy use. For this reason, advanced aviation countries such as the United States and the European Union are leading the development of innovative technologies to implement the full-electric airplane in the future. Currently, the research and development to convert existing two-seater engine airplanes to electric-powered airplanes are underway domestically. The airplane converted to electric propulsion is the KLA-100, which aims to carry out a 30-minute flight test with a battery pack installed using the engine mounting space and copilot space. The lithium-ion battery installed on the airplane converted to electric propulsion was designed with a specific power of 150Wh/kg, weight of 200kg, and a C-rate 3~4. This study confirmed the possibility of a 30-minute flight with a designed battery pack before conducting a flight test of a modified electrically propelled airplane. The battery performance was verified by dividing the 30-minute flight profile into start/run stage, take-off stage, climbing stage, cruise stage, descending stage, and landing/run stage. The final target of the 30-minute flight was evaluated by calculating the battery capacity required for each stage. Furthermore, the flight performance of the electrically propelled airplane was determined by calculating the flight availability time and navigation distance according to the flight speed.

• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.525-529
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• 2022

In the eLoran system, the Loran Data Channel (LDC) is used to provide precise timing and positioning. The LDC message can be modulated with the Eurofix method, which modulates the transmission time of the 3rd-8th pulse not used for navigation, and the 9th pulse method, which modulates data using the 9th additional pulse after the existing 8 Loran pulses. In this paper, we analyzed the reception performance of the LDC message transmitted from the eLoran transmitter according to the modulation method. The eLoran testbed transmitter in Incheon was set to transmit LDC messages simultaneously with the 9th pulse modulation method and the Eurofix modulation method. Then, the LDC messages stored in the databases of the eLoran differential stations in Incheon and Pyeongtaek were analyzed in terms of the message reception rate according to the modulation method. Using the navigation aid management ship Inseong No. 1, the range of LDC message reception of actual sea users near Incheon Port was also analyzed. The results of this study are expected to be utilized in the full operational capability service after the eLoran pilot service.

• Journal of Advanced Technology Convergence
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• v.1 no.1
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• pp.15-24
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• 2022

This paper tried to investigate the moderating effect of chemyon sensitivity and usage situation in the relationship between self-presentation and brand preference. Data were collected from students of universities located in Chungnam. The analysis results can be summarized as follows. First of all, the effect of self-presentation on symbolic brand preference was not significant in both public and private use situations. On the other hand, the effect of self-presentation on functional brand preference was found to be significant in both situations. Second, the main effect of chemyon sensitivity was significant only when it had a negative effect on functional brand preference in public situations, but was not significant in other cases. Third, looking at the interaction effect of self-presentation and chemyon sensitivity, the brand preference did not show significant changes in those with relatively low chemyon sensitivity, regardless of the level of self-presentation, whether in public or private situations. This study is meaningful in that it reveals that chemyon sensitivity affects brand preference through interaction with self-presentation, whether the consumption situation is public or private.

• Journal of the Korean Geotechnical Society
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• v.23 no.7
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• pp.5-16
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• 2007

The monitoring and investigation of underwater landslide help to understand its mechanism, increase the usefuless of design and construction and reduce the losses. This paper presents three high resolution geophysical techniques electrical resisitance, ultrasonic wave reflection imaging, and shear wave tomography conducted to determine the lab-scaled submerged landslide. Electrical resistance profiles of a soil mass obtained by an electrical resistance probe provide detailed information to assess the spatial distribution of the soil mass with milimetric resolution. An ultrasonic wave image obtained by recording the reflections from interfaces of different impedance materials permits detecting layers and landslide with submilimetric resolution. The pixel based image of immersed landslides is created by the inversion of the boundary information achieved from the traveling time of shear waves. The experimental results show that the ultrasonic wave imaging and the electrical resistance can provide complementary information; and their association with S-wave tomography image can produce a 3-D view of the underwater landslide. This study suggests that geophysical techniques may be effective tools for the detection of the underwater landslides and spatial distribution offshore.

• Korea Trade Review
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• v.41 no.3
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• pp.1-25
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• 2016

This study reviews international discussions about the trade-labor linkage and examines the labor chapters of FTAs enforced by the US and the EU from a comparative perspective. Since early 1990s, starting from the NAFTA, the US has included forceable labor provisions in its FTAs and this trend continues to the TPP which was concluded in October 2015. On the other hand, the EU's labor provisions in its FTAs have been composed of promotional elements on labor rights based on cooperations and dialogues. These different features of labor provisions in the US and European FTAs are mainly due to the motives of the FTAs of the US and the EU respectively as well as their domestic situations with regards to domestic law and institutional set-ups. The coordination of labor provisions involves a long-term institutional as well as regulatory convergence which triggers not only economic but also social changes, compared to a relatively short-term effect of tariff elimination. For Korea which has been a FTA partner country both with the US and the EU, it is significant to keep the different characteristics in the labor provisions in mind, particularly in the process of its implementation. Concerning the implementation of Korea-US FTA, it might be problematic if Korean law and its regulatory practice on labor-management relations do not comply with that of the US. The Korea-EU FTA case can also have an indirect impact on Korea's labor laws since it stipulates in its provisions that both parties should have discussions not only within each government but also with the civil communities including NGOs. Thus, Korea should pay more attention to the true meaning in labor provisions of both FTAs in order to promote its firms to be equipped with the right labor-management system in their operations abroad.

• SUVANNABHUMI
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• v.2 no.2
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• pp.29-51
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• 2010

The diversity of Southeast Asia can be also represented at the tremendous number of ethnic groups residing throughout its various regions even beyond national boundaries. What does it mean by the composite of numerous peoples? It has triggered a lot of problems in a nation or overall Southeast Asia. Among them, the most serious one seems to be ethnic conflicts having damaged national integration and caused political, economical, and social instability. In that respect, Karen people have been a minority group situated in the most chronic dispute in Myanmar. Since 1947 some of the Karen equipped with armed forces have been fighting against the military government currently ruling Myanmar. As the result, the refugees over 200,000 population had moved to the mountain camps located at neighboring Thailand, attracting a lot of attention throughout international societies. According to 1931 census by British colonial government, the Karen have the greatest numbers in population as minority and include 16 subgroups including Karenni(Kayah) and Pa-O seemingly excluded from its category in contemporary point of view. It means that Karen people should not be regarded as an ethnic group, and in fact do not show a homogeneous identity under the title of Karen. Given the situation, we need to reconsider the category of Karen. What does the Karen mean in a real sense? Previous studies on the Karen had been performed mainly by anthropologists or missionaries such as Marshall(1922), Hamilton (1976), Hanson Tadaw(1959), Smeaton(1920), Keyes(1979), Hayami (1992; 2004), etc. Most of them examined the Karen as a group and ignored the possibilities of representing the divergent identities vis-à-vis their subgroups. Therefore, they have focused on the myth to convert Karen people to Christianity, although the Christian Karens are less than 20% of total population. As a result, I argue that they would fail to define the real meaning of Karen. It has been caused us to recognize the Karen as a meaningless total entity to be accepted by all means. According to their arguments, the difference among Karen's subgroups is just dealt with the trivial matters that do not affect the ethnic boundary itself, still maintaining the ethnic identity as Karen. As we shall see on this thesis, this is never the case. My thesis aims at uncovering and scrutinizing the real meaning of the category of Karen. For the purpose of it, I will consider Karen people as a linguistic group from the beginning as shown in 1931 census. I argue that the Karen have been affected or exposed by various conditions or environments throughout the harsh history having happened on the areas of current Myanmar and Thailand, leading the vicissitudes of their ethnic identities.

• Tunnel and Underground Space
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• v.33 no.3
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• pp.189-207
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• 2023

In the present study, the thermoshearing experiment on a rough rock fracture were modeled using a three-dimensional grain-based distinct element model (GBDEM). The experiment was conducted by the Korea Institute of Construction Technology to investigate the progressive shear failure of fracture under the influence of thermal stress in a critical stress state. The numerical model employs an assembly of multiple polyhedral grains and their interfaces to represent the rock sample, and calculates the coupled thermo-mechanical behavior of the grains (blocks) and the interfaces (contacts) using 3DEC, a DEM code. The primary focus was on simulating the temperature evolution, generation of thermal stress, and shear and normal displacements of the fracture. Two fracture models, namely the mated fracture model and the unmated fracture model, were constructed based on the degree of surface matedness, and their respective behaviors were compared and analyzed. By leveraging the advantage of the DEM, the contact area between the fracture surfaces was continuously monitored during the simulation, enabling an examination of its influence on shear behavior. The numerical results demonstrated distinct differences depending on the degree of the surface matedness at the initial stage. In the mated fracture model, where the surfaces were in almost full contact, the characteristic stages of peak stress and residual stress commonly observed in shear behavior of natural rock joints were reasonably replicated, despite exhibiting discrepancies with the experimental results. The analysis of contact area variation over time confirmed that our numerical model effectively simulated the abrupt normal dilation and shear slip, stress softening phenomenon, and transition to the residual state that occur during the peak stress stage. The unmated fracture model, which closely resembled the experimental specimen, showed qualitative agreement with the experimental observations, including heat transfer characteristics, the progressive shear failure process induced by heating, and the increase in thermal stress. However, there were some mismatches between the numerical and experimental results regarding the onset of fracture slip and the magnitudes of fracture stress and displacement. This research was conducted as part of DECOVALEX-2023 Task G, and we expect the numerical model to be enhanced through continued collaboration with other research teams and validated in further studies.

• Journal of Food Hygiene and Safety
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• v.38 no.6
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• pp.476-482
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• 2023

This study aimed to investigate the acrylamide content in frozen food products after cooking. Twenty samples of bread (Group 1) and 30 samples of processed tuberous and corn vegetable products (Group 2) were selected. Acrylamide levels were quantified using liquid chromatography tandem-mass spectrometry (LC-MS/MS). The frozen food samples were heated using the air fryer cooking method according to the product packaging and were compared to ready-to-eat French fries (Group 3). The results showed that the acrylamide content was the highest in group 3, followed by that in group 2 and group 1. The acrylamide content of all the samples was found to be within the domestic recommended standard of 1 mg/kg. However, when the samples that exceeded EU benchmark level (0.5 mg/kg) were selected and cooked using the deep-fat frying method according to the product packaging, one of them showed the acrylamide content of 1.83 mg/kg, which exceeded the domestic recommended standard. The present study highlights the need for continued evaluation and management to reduce acrylamide contents in frozen foods, as increasing domestic exposure to acrylamide is concerning.

• Pediatric Infection and Vaccine
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• v.23 no.2
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• pp.109-116
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• 2016

Purpose: Recent observational studies have found that vitamin D deficiency is associated with respiratory tract infections. However, randomized controlled trials (RCTs) regarding the efficacy of vitamin D in childhood respiratory tract infection (RTI) have yield inconsistent results. We performed a systematic review and meta-analysis to evaluate the association between vitamin D supplementation and the risk of RTI. Methods: A comprehensive search was conducted using MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trial. Randomized controlled trials of vitamin D supplementation for prevention of RTI in children were included for the analysis. Cochrane Collaboration's tool for assessing the risk of bias was used to assess the quality of the studies. Pooled risk ratios with 95% confidence intervals (CIs) were meta-analyzed using Review Manager 5.3. Results: A total of seven RCTs were included in the meta-analysis. According to a random-effects model, the risk ratio for vitamin D supplementation was 0.82 (95% CI: 0.69-0.98) and $I^2=62%$ for heterogeneity. On subgroup analysis, heterogeneity decreased in the subgroup with follow-up less than 1 year, participants ${\geq}5years$ of age, patients subgroup, and subgroup with dosing daily. Funnel plot showed that there might be publication bias in the field. Conclusions: The present meta-analysis supports a beneficial effect of vitamin D supplementation for the prevention of RTI in children. However, the result should be interpreted with caution due to limitations including a small number of available RCTs, heterogeneity among the studies, and potential publication bias.