• Korean Journal of Environmental Agriculture
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• v.38 no.3
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• pp.205-212
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• 2019

BACKGROUND: This survey conducted on agricultural products in Incheon for the past three years from 2016 to 2018 to detect residual pesticides and to monitor the use of pesticides. METHODS AND RESULTS: Residual pesticides were analyzed for a total of 5,937 agricultural products in Samsan wholesale market, traditional market and large retailers in Incheon. Samples were analyzed by multi class pesticide method using GC-MS/MS, LC-MS/MS, GC-ECD/NPD, and UHPLC. In 59 cases (1.0%) residual pesticides were detected improperly and these cases exceeded maximum residue limits (MRLs). CONCLUSION: The ratios of violative agricultural products were similar each year at approximately 1.0% per year, but the residual pesticide detection rates with the limit included in the samples were shown to be gradually decreasing to 17.9%, 12.6%, and 11.2% annually. The frequency of violative residual pesticides was high in order of Diazinon, Chlorpyrifos, Iprodione, etc. Residual pesticide monitoring might be needed in the future continuously, as violations in agricultural products distributed in Incheon are shown at a similar level every year.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.6
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• pp.242-252
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• 2018

It is well known that an Oscillating Water Column Wave Energy Converter (OWC-WEC) is one of the most efficient wave absorber equipment. This device transforms the vertical motion of water column in the air chamber into the air flow velocity and produces electricity from the driving force of turbine as represented by the Wells turbine. Therefore, in order to obtain high electric energy, it is necessary to amplify the water surface vibration by inducing resonance of the piston mode in the water surface fluctuation in the air chamber. In this study, a new type of OWC-WEC with a seawater channel is used, and the wave deformation by the structure, water surface fluctuation in the air chamber, air outflow velocity from the nozzle and seawater flow velocity in the seawater channel are evaluated by numerical analysis in detail. The numerical analysis model uses open CFD code OLAFLOW model based on multi-phase analysis technique of Navier-Stokes solver. To validate model, numerical results and existing experimental results are compared and discussed. It is revealed within the scope of this study that the air flow velocity at nozzle increases as the Ursell number becomes larger, and the air velocity that flows out from the inside of the air chamber is larger than the velocity of incoming air into the air chamber.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.553-560
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• 2020

This paper presents an algorithm for identifying and eliminating errors by seagrasses in coastal bathymetry surveying using drone and HD camera. Survey errors due to seagrasses were identified, segmentated and eliminated using a L∗a∗b color space model. Bathymetry survey using a drone and HD camera has many advantages over conventional survey methods such as ship-board acoustic sounder or manual level survey which are time consuming and expensive. However, errors caused by sea bed reflectance due to seagrasses habitat hamper the development of new surveying tool. Seagrasses are the flowering plants which start to grow in November and flourish to maximum density until April in Korea. We developed a new algorithm for identifying seagrasses habitat locations and eliminating errors due to seagrasses to get the accurate depth survey data. We tested our algorithm at Wolpo beach. Bathymetry survey data which were obtained using a drone with HD camera and calibrated to eliminate errors due to seagrasses, were compared with depth survey data obtained using ship-board multi-beam acoustic sounder. The abnormal bathymetry data which are defined as the excess of 1.5 times of a standard deviation of random errors, are composed of 8.6% of the test site of area of 200 m by 300 m. By applying the developed algorithm, 92% of abnnormal bathymetry data were successfully eliminated and 33% of RMS errors were reduced.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.10
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• pp.3-12
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• 2018

This research aims at analyzing the changes in residential environment after a residential environment improvement project focusing on the analysis into the physical environment of a residential environment improvement project, and examining in what direction the changes by residents' own efforts occurred after public support, such as infrastructure. The present residence development method has become different from the previous pulling down method and is focused on regeneration. By examining in what direction the target residence is being changed because of the development by residents' own efforts after the government's public investment at this time, this study also aims at investigating the direction to develop a guideline for residential improvement for later improvement of deteriorated residence. As for the contents of the analysis, changes in public support, such as infrastructure, and other areas after the residential environment improvement project were compared and analyzed from the land use, street system, and condition of buildings before the residential environment improvement project through field survey, geographic information system(GIS), registered land and building data and so on. The biggest change since the support from the government was that at the beginning of the project, the application of special provision of building laws and different financial supports led to lots of newly built buildings. Since then, their number has decreased rapidly, and in most cases, there have been some changes in part, such as changes in the use of land or repair of disposal tanks. Most newly built buildings were multi-household houses, and it has caused road capacity and parking lot capacity, etc., to be exceeded, which has worsened the pleasantness of the living environment. In addition, other problems have also appeared, for example, the lack of residence supporting facilities yet with a higher level of residential density. Regarding the changes in the residential environment after the residential environment improvement project, maintenance of houses were conducted in some degree as diverse alleviation policies to improve poor residence, yet the absence of the guideline for the direction of developing the whole district has made the residence environment more dense and deteriorated. To solve these problems, in advance to a residential improvement project, specific management methods based on short-, mid- and long-term plans for the direction of development by residents' own efforts and a sustainable guideline seem to be necessary.

• 한국사회정책
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• v.24 no.2
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• pp.61-86
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• 2017

Along with the well-established evidence on the negative effect of social isolation on physical and mental health, increasing attention has been paid to multi-dimensional nature of social isolation. One line of study on social isolation has discussed different pathways between objective and subjective social isolation and health. Another stream of the research focused on the possibly non-linear association between social isolation and health by age cohort groups. Drawing from the two lines of research, this study aimed at empirically examine to what extent objective and subjective social isolation are associated with physical and mental health independently and how the associations vary by three age cohorts(i.e. the middle-aged, the young old, the old-old). Data came from the first wave of Korean Social Life, Health and Aging Project (KSHAP) (N= 814). Findings showed 1) objective subjective isolation were significantly related with worse physical and mental health, interestingly, subjective social isolation was associated with mental health only, 2) pattern of association between social isolation and physical health varied by age cohorts. Specifically, compared to the middle-aged, the young old with higher objective social isolation exhibited lower level of physical health, while the old-old with higher subjective social isolation were likely to experience lower physical health. Based on the findings, we discussed implications and suggestions for future research and relevant policy/program development for ameliorating objective and subjective social isolation.

• Journal of Family Relations
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• v.22 no.4
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• pp.135-156
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• 2018

Objectives: This study aim to determine adolescent meal time, which provides the important context of parent-child sharing time. We divided mealtime into family meal and alone meal, and analyzed the time/space context of each meal time as well as the social determinations. Method: We employed adolescents age 10-18 who live with married patents and attends school at the present (n=5,128) from the original data of Korean Time Use Survey. Results: More adolescent were engaged in family meal rather than eating alone in daily bases. However, the trend show difference by day of week and academic grade; family meal are more prevalent in weekends rather than weekdays. As adolescent reaches high school age, the proportion of eating alone beats the proportion of family meal time. Most of the meal occur at home. Having meal outside was relatively scares, especially on weekdays. Tobit and logistic analysis reveal that, on weekday meal, less school hours, more time spent at the private academy, having family leisure event, and long mother's housework hours were positively associated with family meal time. In weekend model, father's education gradient was associated with family meal time, showing higher the father's education level, there were higher chance of having weekend family meal. As for the eating alone, relevant factors were similar with family meal but the directions were the opposite; having family leisure were negatively associated with alone meal, both weekdays and weekend. Long academy hours, meal preparing and leisure alone were positively associated eating alone. Overall, weekday meal time was strongly linked with adolescent daily schedules and time use, while for weekends meal, in both family meal and alone meal, the influence of parent factors were discovered. Conclusion: The results indicates that alone meal and the family meal are not exclusively related but seem to be complementary. Families tend to enjoy family meal yet, there are some necessary situation that adolescent need to be on their own. Increase in ready-made food industries, growing independence of children by age seem partly allow adolescent children to eat alone. Careful attentions may require for monitoring weekends meal situation and the family factor of adolescent in future studies.

• Journal of the Korean Society for Library and Information Science
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• v.55 no.1
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• pp.365-392
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• 2021

In order to assess the state of library and information science (LIS) research in Korea, the study analyzed bibliometric data of papers published in past 18 years in Korea Citation Index (KCI) and Social Science Citation Index (SSCI) journals. The analysis of study data, which consisted of 6,301 KCI journal papers with 26,474 citations and 86,727 SSCI journal papers with 1,196,961 citations from 2002 to 2020, involved comparison of research productivity and impact, collaboration trends, and key areas of research between domestic and international LIS scholars with normalizations by units of analysis for size differences. Even with size normalization, the study found a marked difference in citation patterns between domestic and international LIS research. Korean LIS authors were twice as productive as international LIS authors but a little over a half as impactful. The results also showed a much higher level of skewness in international research, where a fraction of top authors, institutions, and journals received a lion's share of citations. The trend of increasing co-authorship was much more pronounced among international publication, where the recent popularity of larger collaboration groups suggests multi-disciplinary and increasingly complex nature of modern LIS research in the world stage. The keyword analysis revealed a much more diverse subject area in international than domestic LIS research with a recent shift towards technology, such as big data, blockchain, and altmetrics. Keywords in SSCI journals also exhibited a less connection between popularity and impact than KCI keywords, where popular keywords did not necessarily correspond to impactful keywords.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.212-220
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• 2021

National R&D investment has steadily increased, reaching number 5 in the world as of 2018. However, for public technology commercialization, the level of discovery of policy models through various cooperation initiatives between government ministries is insufficient, and the performance system that can spread technology commercialization is also limited. In this respect, in order to create results in public technology commercialization, it is necessary to prepare alternatives to strengthen multi-ministerial policy cooperation and increase policy execution power. In this paper, we analyzed the current state of national R&D projects by major ministries and suggested an optimized technology commercialization plan through analysis of the structure, budget, and form of each project. In particular, an alternative in terms of policy efficiency was suggested by analyzing the problems of policy discovery that have not been studied previously. This study is of great significance in that it diagnosed problems of public technology commercialization in terms of the lack of systematic research on public technology commercialization and suggested policy advancement for the spread of technology use and the strategic direction in terms of commercialization.

• The Journal of the Korea Contents Association
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• v.21 no.3
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• pp.720-729
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• 2021

The purpose of this study was to measure repeated the process of non-suicidal self-injury individuals change in everyday life through the Ecological Momentary Assessment(EMA) daily diary. The study subjects of were 17 adults aged 19 to 29, accessed a link sent by text message on a cell phone and recorded a diary of the day's affects, interpersonal conflicts, self-injury thoughts, and behaviors once a day for two weeks. Using a total of 238 reported entries, the contextual factors of NSSI were examined, and the effects of affects and interpersonal conflicts on NSSI analyzed through a multi-level model. As a result, the negative affects of that day have a significant relation with within subject NSSI behavior and positive affects have a significant relation between subject NSSI behavior. These findings means that overall individuals with low positive affects have a higher risk of self-injury behavior compared to those with higher levles of positive emotions, and an increase in negative emotions on that day within an individual increases the risk of self-injury behavior on that day. In other words, it implies that it is important to manage negative emotions and strengthen overall positive affects for that day in the intervention of emotion-regulation of experienced self-injury individuals. It is meaningful that this study explored NSSI risk factors experienced in daily life through the short-term longitudinal study.

• Journal of Aerospace System Engineering
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• v.15 no.1
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• pp.86-94
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• 2021

PCB-based deployable solar panel is mainly used for CubeSat due to its lightweight and easy of electrical connection. However, as the size of solar panel increases, there is a limit to ensuring the structural safety of solar cells due to excessive dynamic displacement under launch vibration environment. In previous mechanical designs, for the minimization of dynamic deflection, panel stiffness is increased by applying additional stiffeners made of various materials such as aluminum or composite. However, it could have disadvantages for CubeSat design requirements due to limited mass and volumes. In this study, a high-damping 6U solar panel was proposed. It had superior damping characteristic with a multi-layered stiffener laminated with viscoelastic acrylic tapes. Basic characteristics of this solar panel were measured through free-vibration tests. Design effectiveness of the solar panel was validated through qualification-level launch vibration test. Based on test results, vibration characteristics of a typical PCB solar panel and the high-damping laminated solar panel were predicted and a comparative analysis was performed.