• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.304-310
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• 2015

The moisture content of sawdust must be measured accurately and controlled appropriately during storage and transportation because biological degradation could be caused by improper moisture. In this study, to measure the moisture contents of Larix kaempferi sawdust, the near-infrared reflectance spectra (Wavelength 1000-2400 nm) of sawdust were used as detection parameter. After acquiring the NIR reflection spectrum of specimens which were humidified at each relative humidity condition ($25^{\circ}C$, RH 30~99%), moisture content prediction model was developed using mathematical preprocessings (e.g. smoothing, standard normal variate) and partial least squares (PLS) analysis with the acquired spectrum data. High reliability of the MC regression model with NIR spectroscopy was verified by cross validation test ($R^2$ = 0.94, RMSEP = 1.544). The results of this study show that NIR spectroscopy could be used as a convenient and accurate method for the nondestructive determination of moisture content of sawdust, which could lead to optimize wood utilization.

• Journal of the Korean Wood Science and Technology
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• v.38 no.4
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• pp.306-315
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• 2010

The stress laminated timber, which could be manufactured by small dimension lumber on construction site, has high possibilities for bridges in remote area, such as recreation forest or forest road, because those bridges may be short span and low frequency in use. The stress laminated timber has merits of easiness for preservative treatment and transportation because it is manufactured with small dimension lumber. This study was carried out to analyze performances of stress laminated timber manufactured with preservative treated domestic pitch pine for developing structural design data for stress laminated timber bridges for vehicular traffic. Perpendicular to grain compressive performance by preservative treatment and bending performance by bored holes of pitch pine lumber was analyzed. Then, the effects of bending performance by pre-stress pressure, distance of bolts, number of laminations and planning were analyzed. Conclusively, planning of lumber was not necessary for manufacturing stress laminated timber, and 80% of bending stiffness criteria was maintained as pre-stress pressure was higher than 3.0 kg/$cm^2$. However, further researches are needed to define the effects of bolt distances and number of laminations. The results of this research would be basic data for design stress laminated timber bridges for vehicular traffic in Korea.

• Journal of Wetlands Research
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• v.18 no.2
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• pp.183-193
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• 2016

In this study, design and performance of infiltration trench using woodchip as media for treating stormwater from highway were examined through field monitoring. Average reduction efficiency for TSS, COD, BOD, TN, and TP was 88%, 94%, 85%, 80%, and 75% respectively, which is similar to values reported by other studies and design manuals even though direct comparison is not possible due to different monitoring and design conditions. Mean field infiltration rate estimated by measuring the change of water depth inside the observation well was about 40mm/hr, and the time taken for complete infiltration was about 0.83days, which corresponds well with design criteria recommended by MOE guidelines in Korea. In addition, according to analysis of infiltration rate and reduction efficiency, effective rainfall depth applied for determining water quality volume(WQv), 5mm was found to be properly established as design criteria. Woodchip must be considered and included as an alternative media together with crushed rock and gravel into the design guidelines because it has more advantages in terms of weight, porosity, cost, and easiness of management than other media materials.

• Journal of Korea Water Resources Association
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• v.49 no.4
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• pp.327-333
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• 2016

Due to climate changes accelerated by global warming, South Korea has experienced regional climate variations as well as increasing severities and frequencies of extreme weather. The precipitation in South Korea during the summer season in 2013 was concentrated mainly in the central region; the maximum number of rainy days were recorded in the central region while the southern region had the minimum number of rainy days. As a result, much attention has been paid to the importance of flood control due to damage caused by spatiotemporal intensive rainfalls. In this study, forecast rainfall data was used for rapid responses to prevent disasters during flood seasons. For this purpose, the applicability of numerical weather forecast data was analyzed using the ground observation rainfall and inflow rate. Correlation coefficient, maximum rainfall intensity percent error and total rainfall percent error were used for the quantitative comparison of ground observation rainfall data. In addition, correlation coefficient, Nash-Sutcliffe efficiency coefficient, and standardized RMSE were used for the quantitative comparison of inflow rate. As a result of the simulation, the correlation coefficient up to six hours was 0.7 or higher, indicating a high correlation. Furthermore, the Nash-Sutcliffe efficiency coefficient was positive until six hours, confirming the applicability of forecast rainfall.

• The Journal of Korean Society for School & Community Health Education
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• v.1 no.1
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• pp.61-82
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• 2000

The purpose of this study was to find out the general problems of school food service and to explore a way to improve it, by examining elementary school teacher's consciousness and attitude toward it that gave a big impact on children's development of food habit. For attaining the purpose, the following research questions were posed : 1) What's elementary school teacher attitude toward school food service management? 2) What's elementary school teacher attitude toward school food service effect on children? 3) What's elementary school teacher opinion about how to develop school food service? The subjects of study were 328 male or female teachers who served at elementary school in urban and rural area, including eup, myon, or farming and fishing villages, Kyonggi province. A questionnaire survey was conducted over them. The conclusions were as follows: 1) Teacher Attitude Toward School Food Service Management Concerning food service place, the subjects were more satisfied at food service room(73.3%) than at classroom(23.0%). They responded that food service room was more effective, than classroom, for food transportation, distribution and post-arrangement. Their satisfaction at food service place was significantly different. The older teachers considered personnel management and cooking room's sanitary management to be more efficient, and their age made a significant difference to their consciousness of these things. Many teachers(63.1%) thought the measures to prevent and manage group food poisoning were relatively efficient. The male teachers expressed more affirmative view on the efficiency of school food expense management and menu preparation than female teachers, and there was a significant disparity between male and female teachers. 2) Elementary School Food Service Effect School food service was thought to be very effective for physical growth(74.1%) and physical strength improvement(70.1%). Teachers at smaller school revealed more affirmative response toward school food service effect on correcting an unbalanced diet, and older teachers considered its effect on nutrition knowledge acquisition and learning outcome to be more great. Teachers at larger school put less value on its effect on table manners, and school size produced a significant difference. The number of teachers who thought school food service generally raised parent concern and support for school(36.6%) was a little more than that of teachers who didn't think so(15.2%). And the number of teachers who didn't consider its effect on improving parent food life to be good(29.3%) was slightly more than that of teachers who did. 3) School Food Service Reform Measure What's most urgently needed for better school food service management appeared to be an expansion of facilities concerned, followed by more effective food distribution and transport, cooking room's better sanitary management, more successful food poisoning prevention and management, more effective food expense management, and an increase of food service personnel in the order named. The most effective means of school food service education was found to be a creation of link system to family, followed by a development of school food service education program, a development of teaching materials, an insertion of school food service in curriculum, and teacher education in the order named.

• Food Science and Preservation
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• v.23 no.4
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• pp.471-478
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• 2016

For the distribution of fresh produce, the thermoelectric cooling system combined with thermo electric materials (TEM) and phase change material (PCM) was studied. The PCM used this study was produced by in-situ polymerization technology which referred microencapsulation of hydrocarbon (n-tetradecane and n-hexadecane). In this study, quality characteristics of bell peppers in thermoelectric cooling system combined with TEM and PCM were analyzed and control was placed in an EPS (expanded polystyrene) box. As a result of quality characteristics analysis, weight of bell peppers decreased and moisture content of bell peppers was 90.96~94.43% during storage. Vitamin C content of bell pepper decreased during storage and reduction ratio of control was higher than that of BPT-5 treatment(bell pepper in thermoelectric cooling system with PCM which is kept the temperature at $5^{\circ}C$). The result of color value, on 21 day, ${\Delta}E$ value of BPT-5 treatment was 5.05 while that of control was 41.8. On 21 day, total bacteria count of BPT-5 treated bell pepper shown less than that of control. In conclusion, it suggested that the thermoelectric cooling system combined with PCM improved quality of fresh produce during transportation and storage.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.1
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• pp.15-21
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• 2020

This study analyzes the results of applying the ISO19030 (hull and propeller performance monitoring method) standard to an actual 178 k bulk vessel. Recently, there have been many attempts to apply various energy reduction solutions to vessels to continuously strengthen GHG reduction regulations and secure maritime competitiveness. However, it is not easy to quantitatively analyze the performance of a ship. To resolve these problems, shipping companies, marine paint companies, ship owners, and transportation associations have appointed specialists and standardized the ISO19030 (standard of hull and propeller performance monitoring method) guidelines in 2016 after three years of continuous review. The ISO19030 standard provides methods to monitor hull and propeller performance quantitatively through standardized procedures, thus allowing ship managers to arrive at informed decisions for hull and propeller maintenance, and to evaluate energy-saving solutions and ship-maintenance efficiency. The ISO19030 standard provides a method of analyzing the ship's own performance by collecting the ship's operation and agency data and correcting its environmental and operating factors. In this paper, we apply the ISO19030 standard to three actual ships and propose the ISO19030 application result and the improvement point of the current ISO19030 standard.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.1
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• pp.39-46
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• 2020

Accident prevention is more important than follow-up, which is based on Heinrich's law. The marine incident system is a very meaningful system that can prevent similar accidents, and was introduced in 2010 in Korea in accordance with the enforcement of the Code for the Investigation of Marine Casualties and Incidents (CI Code). Based on the CI Code, ship owners or ship operators are required to notify the Central Chief Inspector using the designated notification form in the event of a marine incident, but the number of voluntary notifications is still small. In this regard, this study intends to provide a direction for improvement by conducting an in-depth analysis focusing on the lack of notification procedures and forms of the marine incident system. To this end, we analyzed related regulations, cases of excellent overseas shipping countries such as the United Kingdom and Singapore, cases of similar domestic transportation systems such as aviation and railways, and marine incident notification procedures and forms of leading shipping companies. Major improvements in the notification process include the transition of the marine incidents to voluntary reporting, the expansion of the reporting subjects, and the identification of the security of the informer's identity. The main contents of the notification form revision include the use of the term "reporting" instead of "notification," the content of the identity guarantee in the notification form, and the increase in statistical value through the expansion of optional entries.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.374-381
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• 2020

According to international regulations, it is mandatory for navigators or engineers to acquire suitable skillsets before their designation as a duty officer on board. One of the most important elements is Maritime English (ME), wherein students are taught a required set of basic skills that enable them to process various documents related to accidents, ship conditions, and inspections. Students have to be equipped not only with the use of general English skills but also with the coherent use of technical terms and phrases. However, due to the unique circumstances that exist in the maritime domain, the methods used for imparting maritime knowledge and the manner in which it is evaluated are restricted. Hence, this study aims to utilize an online Maritime English learning and testing platform that can be accessed on smart devices to analyze its impact on the students' learning process. An experiment was conducted on two groups of cadets, one that used the platform and another group that did not. After six-week, the experiment results showed a significant difference between the ME test scores of the two groups. The test scores were further analyzed by incorporating the students' personal elements to measure the ef icacy of the ME test platform. Therefore, the learning and evaluation processes are expected to be implemented in ways that are appropriate and convenient to specific circumstances and be widely used in the field of maritime education in the future.

• Journal of Korea Water Resources Association
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• v.51 no.8
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• pp.729-737
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• 2018

This study investigates the sediment processes the Improved-pneumatic-movable weir through laboratory experiments considering changing channel slopes. Experimental results show that the delta migrates towards the weir and the delta height increases as time passes. Moreover, as the delta approaches the weir, the delta migration speed decreases. As the dimensionless delta location increases, the effective height of dimensionless delta and the dimensionless reservoir capacity increases. Therefore, under the same slope conditions, the sediment deposition volume of the delta is small as the channel slope is mild. This means that the channel slope affects the development of the delta in the upstream of the Improved-pneumatic-movable weir. At the beginning of the experiment, the foreset slope is mild. However, the foreset slope of the delta increases with water depth as the delta migrates downstream. Moreover, as the slope is mild, the ratio of delta front length to delta height is close to 1, and the dimensionless delta height and the dimensionless delta migration speed decrease. As the delta height increases, the water depth, the velocity approaching to the weir and the delta migration speed decrease.