• Journal of Digital Convergence
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• v.18 no.2
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• pp.1-12
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• 2020

This study aimed to select and evaluate policy priorities for the expansion of public and semi-public systems for coastwise passenger transport services. For research methodology, the Consistent Fuzzy Preference Relations (CFPR) method was used to effectively extract expert knowledge. First, the result of the analysis on policy tasks for expanding the semi-public system for coastwise passenger transport services showed that "the establishment of public transportation fare system" was the most important task at 0.160. Second, "conversion of the subsidiary routes to a public system by the central government" was ranked next at the importance of 0.136. The factor named "support through proper allocation of budgets between national and local governments" are ranked third (0.119). The results of this study have practical implications in that it proposed the policy priorities for the expansion of the public semi-public systems for coastwise passenger transport services.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.817-822
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• 2014

Since the opening of the double-track railway for the Gyeongchun local electric train and the semi-high speed train ITX, floating population between Seoul and Chuncheon has rapidly increased. This is attributable to the competitiveness of the railway service in terms of punctuality and safety of operation, mass transportation and low fare. However, many passengers have expressed strong dissatisfaction and displeasure towards the interior noise and its high rate of increase, particularly in tunnel sections. In this study, the interior noise characteristics of Gyeongchun local electric train and ITX were analyzed and compared. Noise levels, frequency spectrum and sound quality indices were compared for the open land, tunnel and bridge. Finally, from the noise levels depending on the location in the vehicle compartment, the noise transmission path was determined and a basic strategy for reducing the interior noise was developed.

• Smart Structures and Systems
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• v.19 no.4
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• pp.341-350
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• 2017

Based on the super elastic properties of the shape memory alloy (SMA) and the inverse piezoelectric effect of piezoelectric (PZT) ceramics, a kind of hybrid semi-active control device was designed and made, its mechanical properties test was done under different frequency and different voltage. The local search ability of genetic algorithm is poor, which would fall into the defect of prematurity easily. A kind of adaptive immune memory cloning algorithm(AIMCA) was proposed based on the simulation of clone selection and immune memory process. It can adjust the mutation probability and clone scale adaptively through the way of introducing memory cell and antibody incentive degrees. And performance indicator based on the modal controllable degree was taken as antigen-antibody affinity function, the optimization analysis of damper layout in a space truss structure was done. The structural seismic response was analyzed by applying the neural network prediction model and T-S fuzzy logic. Results show that SMA and PZT friction composite damper has a good energy dissipation capacity and stable performance, the bigger voltage, the better energy dissipation ability. Compared with genetic algorithm, the adaptive immune memory clone algorithm overcomes the problem of prematurity effectively. Besides, it has stronger global searching ability, better population diversity and faster convergence speed, makes the damper has a better arrangement position in structural dampers optimization leading to the better damping effect.

• Journal of Astronomy and Space Sciences
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• v.36 no.2
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• pp.61-68
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• 2019

We have investigated the variations of sporadic E (Es) layer using the measurements of digisondes at Icheon ($37.14^{\circ}N$, $127.54^{\circ}E$, IC) and Jeju ($33.4^{\circ}N$, $126.30^{\circ}E$, JJ) in 2011-2018. The Es occurrence rate and its critical frequency (foEs) have peak values in summer at both IC and JJ in consistent with their known seasonal variations at mid-latitudes. The virtual height of the Es layer (h'Es) during equinox months is greater than that in other months. It may be related to the similar variation of meteor peak heights. The h'Es shows the semidiurnal variations with two peaks at early in the morning and late in the afternoon during equinoxes and summer. However, the semi-diurnal variation is not obvious in winter. The semi-diurnal variation is generally thought to be caused by the semi-diurnal tidal variation in the neutral wind shear, whose measurements, however, are rare and not available in the region of interest. To investigate the formation mechanism of Es, we have derived the vertical ion drift velocity using the Horizontal Wind Model (HWM) 14, International Geomagnetic Reference Field, and Naval Research Laboratory Mass Spectrometer and Incoherent Scatter Radar-00 models. Our results show that h'Es preferentially occur at the altitudes where the direction of the vertical ion velocity changes. This result indicates the significant role of ion convergence in the creation of Es.

• The Journal of the Korea Contents Association
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• v.7 no.8
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• pp.21-30
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• 2007

Due to the growth of embedded systems and the development of semi-conductor and storage devices, digital convergence devises is ever growing. Digital convergence devices are equipments into which various functions such as communication, playing movies and wave files and electronic dictionarys are integrated. Example are portable multimedia players(PMPs), personal digital assistants(PDAs), and smart phones. Therefore, these devices need an efficient file system which manages and controls various types of files. In designing such file systems, the size constraint for small embedded systems as well as performance and compatibility should be taken into account. In this paper, we suggest the partial buffer cache technique. Contrary to the traditional buffer cache, the partial buffer cache is used for only the FAT meta data and write-only data. Simulation results show that we could enhance the write performance more than 30% when the file size is larger than about 100 KBytes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.244-250
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• 2020

Microplastic pollution in the marine ecosystem has been emerged as a global issue. In this study, we investigated the abundance of microplastics from clam Meretrix lusoria, blood arkshell Scapharca broughtonii, and warty sea squirt Styela clava obtained from a local market in Busan, Korea. The marine organisms were digested in 10% KOH, and were incubated at 40℃ and 150 rpm, for 7 days. The digest was filtered through standard sieve (5 mm, 1 mm, 300 ㎛, and 100 ㎛), and mciroplastics were identified using a light microscope and microFT-IR. The abundance of microplastics of clam, blood arkshell, warty sea squirt was 0.08 items/g, 0.05 items/g, and 0.12 items/g, respectively. The predominant microplastic size was in the range of 100-300 ㎛, occupying 48%, and the predominant type was fiber. The composition of microplastics was mostly rayon, semi-synthetic cellulosic material and polyester, which are main component of fabric and textile. We strongly believe that this preliminary work may provide useful information for the establishment of the standardized analysis method of microplastics ingested by marine organisms.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.501-508
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• 2021

The purpose of this study is to qualitatively analyze the perceptions of aesthetic values of working women taking ballet fitness classes and to find ways to properly establish ballet fitness classes according to the opinions of the study participants. Participants in the study were 9 working women taking ballet fitness classes at local educational institutions, and FGI (Focus Group Interview) was conducted, and the interview was conducted based on a semi-structured questionnaire. Subsequently, the categorization content was derived through expert review and peer review. As a result, first, the study participants expressed their dissatisfaction, hoping that the ballet fitness class helped improve their daily enjoyment and pain, and even watched ballet performance with interest. Second, the participants of the study were actively publicizing the benefits of ballet fitness classes to their families and nearby acquaintances, and hoped that this exercise would help improve the difficult image of ballet. Based on this study, ballet fitness classes were expected to be sufficiently established as a hobby exercise for working women.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.11-16
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• 2021

Recently, community welfare centers including the elderly welfare centers are also interested in the issue of loneliness and are attempting a comprehensive approach to care for the elderly in the community.The problem is that there is a need for volunteers who are sustainable, but trained semi-professionals rather than non-professionals.Therefore, ways to provide education programs that can be based on continuous supplementation and specialization of manpower and to apply them to the field are being sought.The purpose of this study is to present a plan through examples with the aim of linking college students majoring in social welfare as a major resource for preventing loneliness of elderly people living alone in local communities through volunteer activities. It was suggested that volunteer activities of college students majoring in social welfare should be provided more systematically to the elderly living alone in the community.

• Journal of Industrial Convergence
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• v.21 no.12
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• pp.83-90
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• 2023

The purpose of this study is a descriptive research study to confirm the difference in health empowerment according to the current status and general characteristics of North Korean women defectors residing in South Korea. The subjects of the study were 201 North Korean women defectors living in the local community, and data were collected from September 16 to September 21, 2020 using a structured questionnaire. The collected data were analyzed by descriptive statistics, t-test, ANOVA, pearson's correlation coefficients using the SPSS/WIN 23.0 program. As a result of the study, the domain with the lowest score in the health empowerment of North Korean women defectors was "I know a positive method to cope with stress related to my health care." in the stress management question. Statistically significant differences were found in North Korean repatriation experience(t=3.77, p<.001), education(F=4.56, p=.012), economic status(t=-2.95, p=.004), subjective health status(t=-4.75, p<.001) and subjective stress(t=-2.47, p=.015). Based on the results of this study, alternatives should be prepared to strengthen the health empowerment of North Korean women defectors according to their individual characteristics.