• The Journal of the Acoustical Society of Korea
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• v.41 no.5
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• pp.492-499
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• 2022

This study experimentally investigates the effect of dimensionality reduction of vibration signal on fault diagnosis of a marine engine. By using the principal component analysis, a vibration signal having the dimension of 513 is converted into a low-dimensional signal having the dimension of 1 to 15, and the variation in fault diagnosis accuracy according to the dimensionality change is observed. The vibration signal measured from a full-scale marine generator diesel engine is used, and the contribution of the dimension-reduced signal is quantitatively evaluated using two kinds of variable importance analysis algorithms which are the integrated gradients and the feature permutation methods. As a result of experimental data analysis, the accuracy of the fault diagnosis is shown to improve as the number of dimensions used increases, and when the dimension approaches 10, near-perfect fault classification accuracy is achieved. This shows that the dimension of the vibration signal can be considerably reduced without degrading fault diagnosis accuracy. In the variable importance analysis, the dimension-reduced principal components show higher contribution than the conventional statistical features, which supports the effectiveness of the dimension-reduced signals on fault diagnosis.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.918-927
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• 2022

The purpose of this study was to investigate the causes of collisions by examining 668 cases of merchant ship collision accidents that occurred during the past 12 years (2010-2021) and analyzed them statistically. Further, the analysis results were applied to propose a human error prevention collision avoidance (HEPCA) model. The statistical annual report of the Korea Maritime Safety Tribunal (KMST) and the collision investigation report were investigated to collect data on the causes of collisions of merchant ships, and frequency analysis was performed using the statistical analysis tool, SPSS Statistics. In the first-stage analysis, the causes of collisions were analyzed targeting 668 merchant ship collision accidents, and in the second-stage analysis, the identified maximum frequency cause factors were analyzed in detail. The analysis results identified that 98 % of the cause of the collision was the human error of the navigator, and the highest frequency was in the order of neglect of look-out > violation of navigation regulations > improper maneuvering. The cause of the neglect of look-out was mainly neglecting continuous monitoring after the first recognition of the target ship. The HEPCA model for human error prevention was proposed by applying the analysis results to the collision case of the investigation report. The results of this study are expected to be used as educational materials at marine navigator educational institutions and in practice for avoiding collisions caused by human errors of navigators.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.295-307
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• 2021

The Korean Peninsula is surrounded on three sides by the East Sea, West Sea and South Sea which are connected to many rivers and streams, thereby facilitating easy inflow of debris from land. Furthermore, excessive debris inflow to the sea because of active fishing and various recreational activities. Debris entering the sea are weighted over time and settle in the seabed, thus, making direct monitoring of debris impossible and its collection difficult. Uncollected submerged marine debris affects the seabed ecosystem and water quality and can cause ghost fishing and ship accidents, especially due to waste net ropes and waste fishing gears. Therefore, understanding the debris distribution characteristics is necessary to assist quick collection of these debris (waste net ropes and waste fishing gears). Thus, this study conducted a survey of debris deposited in the seas of 39 ports. Furthermore, distribution characteristics and compositions of submerged marine debris were identified by a map prepared through GIS-based spatial analysis of the East Sea. Consequently, 58% of waste tires in the East Sea were concentrated in breakwaters and ship berthing facilities. Moreover, 26 % of waste plastics were distributed outside the port. Identifying the distinct distribution characteristics of submerged marine debris was difficult; however, compared with others, the distribution of waste plastics was possible outside the port. The findings of this study can serve as baseline data to assist the collection of submerged marine debris using the distribution characteristics.

• The Journal of the Korea Contents Association
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• v.21 no.7
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• pp.238-247
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• 2021

This study is a descriptive research to investigate the, safety environment, and performance of nurses working in public medical institutions on standard precautions for infection, and to identify factors affecting the performance of standard precautions for infection. As for the research method, data were collected through a questionnaire on 192 nurses from two public medical institutions in S city and N city, and the results were analyzed using the SPSS WIN 22.0 statistical program. From the research results, there was a significant difference in the knowledge of standard precautions according to work experience, and there was a significant difference in the safety environment of standard precautions according to the position. The average level of knowledge of standard precautions was 21.98/25 points, the average safety environment was 5.68/7 points, and the average performance was 40.28/60 points. There was a significant positive correlation between the safety environment of standard precautions and the performance of standard precautions (r=.21, p<0.01). The affecting factor on the performance of standard precautions was found to be the safety environment of standard precautions(𝛽=.22, p=.003). Therefore, to improve the performance of standard precautions for nurses' infection control in public medical institutions, Different and persistent infection management educational programs that consider the Historical situation and monitoring are required other than providing financial support and supportive safety environment.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.1
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• pp.15-21
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• 2022

The purpose of our study was to investigate the migration level of lead (Pb), cadmium (Cd), and barium (Ba) from glassware into a food simulant and to evaluate the exposure of each element. The test articles were glassware, including tableware, pots, and other containers. Pb, Cd, and Ba were analysed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The analytical performance of the method was validated in terms of its linearity, limit of detection (LOD), limit of quantification (LOQ), recovery, precision, and uncertainty. The monitoring was performed for 110 samples such as glass cups, containers, pots, and bottles. a food simulant. Migration test was conducted at 25? for 24 hours in a dark place using 4% acetic acid as a food simulant. Based on the data; exposure assessment was carried out to compare the estimated daily intake (EDI) to the human safety criteria. The risk levels of Pb and Ba determined in this study were approximately 1.9% and 0.3% of the provisional tolerable weekly intake (PTWI) and tolerable daily intake (TDI) value, respectively, thereby indicating a low exposure to the population.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.4
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• pp.318-329
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• 2022

Plant phenology including flowering, leaf unfolding, and leaf coloring in a forest is important to understand the forest ecosystem. Temperature rise due to recent climate change, however, can lead to plant phenology change as well as snowfall in winter season. Therefore, accurate monitoring of forest environment changes such as plant phenology and snow cover is essential to understand the climate change effect on forest management. These changes can monitor using a digital camera system. This paper introduces the detection methods for plant phenology and snow cover at the mountain region using an unmanned camera system that is a way to monitor the change of forest environment. In this study, the Automatic Mountain Meteorology Stations (AMOS) operated by Korea Forest Service (KFS) were selected as the testbed sites in order to systematize the plant phenology and snow cover detection in complex mountain areas. Multi-directional Internet Protocol (IP) camera system that is a kind of unmanned camera was installed at AMOS located in Seoul, Pyeongchang, Geochang, and Uljin. To detect the forest plant phenology and snow cover, the Red-Green-Blue (RGB) analysis based on the IP camera imagery was developed. The results produced by using image analysis captured from IP camera showed good performance in comparison with in-situ data. This result indicates that the utilization technique of IP camera system can capture the forest environment effectively and can be applied to various forest fields such as secure safety, forest ecosystem and disaster management, forestry, etc.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.667-675
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• 2022

Agroforestry is an ecological and economic land-use system that enables sustainable agriculture by combining forestry, agriculture, and livestock industries. North Korea chose agroforestry as a strategy for the restoration of sloping land and deforested land. Agroforestry was proposed for the inter-Korean forest cooperation subcommittee meeting and is currently highlighting carbon removal and promoting the '2050 Carbon Neutral Strategy' and 'Korea Peninsula Green Détente.' The study area, Suan-gun, Hwanghaebuk-do, is a constant deforestation monitoring area and a pilot site for management by the International Center for Research in Agroforestry. The requirements for agroforestry were analyzed through literature analysis. The agroforestry site-suitability map was visualized by applying GIS overlap analysis. Approximately 8,839 ha of sloping area was selected as suitable for agroforestry management, which is about 15% of Suan. We compared the map with Google Earth images and visually detected the land use status, such as agroforestry in Suan, to verify the results. As a future study, we will consider both natural-environment and socioeconomic factors and evaluate the relative importance of the factors to produce a high-accuracy agroforestry sitesuitability map at the national scale with the goal of producing basic data for the inter-Korea forest cooperation policy for long-term goals.

• Herbal Formula Science
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• v.30 no.4
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• pp.241-248
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• 2022

Objective : The purpose of this trial is to observe the preliminary effects of Salvia plebeia (SP) extract on quality of life in patients with solid cancer. Methods : This is a prospective, open-label, single-arm, and single-dose clinical trial. Twenty participants who have been diagnosed with solid cancer between the ages of 20 and 65 will be included. All participants will be administered SP granules for 12 weeks. Data will be collected at 4, 8, and 12 weeks after enrollment. The primary outcome is quality of life, using the Korean version of the Functional Assessment Cancer Therapy-General questionnaire. Secondary outcomes include tumor markers in blood tests for each cancer type, soluble programmed death-ligand 1, the percentage of natural killer cells among lymphocytes, ratio of T-helper and T-suppressor cells, ratio of total T, T-helper, T-suppressor, and B cells in lymphocytes, level of C-reactive protein, and tumor size via radiology examination. Safety will be assessed by clinical laboratory tests and monitoring of adverse events. Discussion : This study aims to observe the effects of an oral administration of SP preparations in patients with solid cancer on changes in quality of life and an improvement in immune function. It is expected to provide objective evidence of the effect and safety of SP for patients with solid cancer. Trial registration: KCT0007315 (Clinical Research Information Service)

• Journal of the Korea Society of Computer and Information
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• v.27 no.8
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• pp.195-202
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• 2022

In this study, when cardiopulmonary resuscitation continued for a long time, the rescuer's blood lactic acid concentration, heart rate, and rating of perceived exertion were measured to identify the change in the rescuer's fatigue. Data collection was conducted from July 5 to July 9, 2021, with a total of 24 students, 12 students department of special warfare medical non-commissioned officer, and 12 students department of emergency medical technology at D University, undergoing a two-person alternative chest compression resuscitation for 60 minutes. As a result of the study, the rescuer's blood lactic acid concentration, heart rate, rating of perceived exertion, and chest compression speed were significantly changed according to the duration of CPR (p<.001, p<.001, p<.001, p<.001). blood lactic acid concentrations at every measurement cycle (30 minutes, 40 minutes, 50 minutes, 60 minutes) showed a significant positive correlation with heart rate (r=.696, p<.001, r=.672, p<.001, r=.709, p<.001, r=.782, p<.001), there was also a significant positive correlation with the rating of perceived exertion (r=.476, p<).05, r=.426, p<.05, r=.470, p<.05, r=.470, p<.05). Therefore, monitoring the fatigue of rescuers using heart rate and rating of perceived exertion will be useful for maintaining high-quality chest compression in situations where cardiopulmonary resuscitation is required for a long time.

• Journal of Korea Water Resources Association
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• v.55 no.8
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• pp.577-588
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• 2022

This study aims to identify the limiting nutrient for algal growth in the Geum River and the significant pollutant sources from the tributaries affecting the water quality and to provide a management alternative for an improvement of water quality. An eight-year of daily data (2013~2020) were collected from the Water Environment Information System (water.nier.go.kr) and Water Resources Management Information System (wamis.go.kr). 14 water quality variables were analyzed at five water quality monitoring stations in the Geum River (WQ1-WQ5). In the Geum River, the water quality variables, especially Chl-a vary greatly in downstream of the river. In the open weir gate operation, TP (total phosphorus) and water temperature greatly influence the growth of algae in downstream of the river. A correlation analysis was used to identify the relationship between variables and investigate the factor affecting algal growth in the Geum River. At the downstream station (WQ5), TP and Temp have shown a strong correlation with Chl-a, indicating they significantly influence the algal bloom. The principal component analysis (PCA) was applied to identify and prioritize the major pollutant sources of the two major tributaries of the river, Gab-cheon and Miho-cheon. PCA identifies three major pollutant sources for Gab-cheon and Miho-cheon, respectively. For Gab-cheon, wastewater treatment plant, urban, and agricultural pollutions pollution are identified as significant pollutant sources. For Miho-cheon, agricultural, urban, and forest land are identified as major pollutant sources. PCA seems to be effective in identifying water pollutant sources for the Geum River and its tributaries in detail and thus can be used to develop water quality management strategies.