• Journal of the Korean Solar Energy Society
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• v.24 no.3
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• pp.1-7
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• 2004

Using WAsP, which is PC-program for the vertical and horizontal extrapolation of wind data, annual energy production as well as wind energy density has been predicted for Haengwon wind farm in Jeju island. The predicted results were compared with real data derived from wind turbines in Haengwon wind farm. As the results, in order to produce more electric power, new wind turbines should be located along coastal line, which has comparatively high wind energy density. Also, the roughness length should be inputted to the Map Editor program for better agreement with real annual energy production.

• Korean Journal of Construction Engineering and Management
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• v.23 no.1
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• pp.98-105
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• 2022

It is essential for vertical smart farms that artificially grow crops in an enclosed space to properly utilize air environment facilities to create an appropriate growth environment. However, domestic vertical smart farm companies are creating a growing environment by relying on empirical data rather than systematic methods. Using IoT to create a growing environment based on systematic and precise monitoring can increase crop production yield and maximize profitability. This study aims to construct a monitoring system using IoT and to analyze the cause by demonstrating the imbalance of temperature environment, which is a significant factor in crop cultivation. 1) The horizontal temperature distribution of the multi-layer shelf was measured with different operating methods of LED and air conditioner. As a result, there was a temperature difference of "up to 1.7℃" between the sensors. 2) As a result of measuring the vertical temperature distribution, the temperature difference was "up to 6.3℃". In order to reduce this temperature gap, a strategy for proper arrangement and operation of air conditioning equipment is required.

• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.423-453
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• 2015

This study started with two questions. The first question is 'Why does organic agriculture want to be linked with cooperative?' The second is 'What is the characteristics of the mutual relationship between organic agriculture and cooperative?', especially in Wonju. Up to now, there have been various kinds of discussion about cooperation between organic agricultural campaign and cooperative in Wonju. But there are few concrete data showing what role cooperative plays in the cyclical process of production-distribution-consumption of organic agriculture. Thus, we conducted a survey applying the Delphi technique to the 35 organic agricultural specialists active in Wonju. First, small-scale family farm producers established a social economic cooperative network in around 2003 to perform 'the activities of innovators' through forming an organization. Producers moved from the stage in which they were supported one-sidedly by consumers to the stage where they could 'lead' cooperation. Each farm organization built a vertical integration, and horizontal cooperative systems with other farm organizations. But, practical cooperative activities have remained in the doldrums. They tend to show trends deviating from the principles of organic agriculture and cooperative. Second, the relationship between producers and consumers in Wonju can be described as 'producer-consumer cooperative type'. In Wonju, the producers' organization is not a sub-contractor which simply deliver organic agricultural products to producers' cooperative, but is an equal subject which creates its own value chain. The cooperative (cooperative organization) leads distribution and consumption of organic agricultural products and mutual communication. But, the closeness between producers and consumers has got loosened. And, it is problematic that the proportion of local food consumption in Wonju is very low. There is a very strong tendency to ride the central distribution system of producers' cooperative coalition. Consequently, it is necessary for producers' cooperatives in Wonju to run a local food distribution system based on the 'cooperative system among cooperatives'.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.2
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• pp.129-138
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• 2023

The proportion of agricultural products handled through the Agricultural Products Processing Center (APC) is also steadily increasing every year, and in the case of Seongju Korean melon, a total of 10 APCs of Nonghyup and farming association corporations are in operation, and the distribution ratio is about 60% based on total production. In this study, Seongju Korean melon was selected as a target to analyze the environment load during carrying (production farm ~ APC) in the production area and the transport environment load during distribution of domestic fruits, and to analyze the environmental load for handling at APC. The vertical average vibration intensity (overall G_rms of 1~250 Hz) of truck transport measured at three transport routes from Seongju Korean melon producer ~ APC, Seongju ~ Seoul and Seongju ~ Jeju was about three times larger than that in the lateral direction and 4.5 times larger than that in the longitudinal direction, respectively. The frequency of occurrence of high-amplitude events (G) in the vertical direction compared to the measuring time was deeply related to pavement conditions in the order of unpaved farm-roads, concretepaved farm-roads, and asphalt-paved main-roads, but overall G_rms for the entire frequency band is believed to have a greater impact on vehicle traveling speed than road conditions. On the other hand, the difference in the size and direction of the vibration intensity measured by the forklift truck's main-body and the attachment (fork carrier) during handling at Seongju Korean melon APC was clear, and the vibration intensity of the forklift truck's main-body was largely affected by the stiffness of the fork and the mast according to the handling weight. Based on the field-data of the transport environment during domestic distribution measured through this study, it is believed that it is possible to develop a lab-based simulation protocol for appropriate packaging design.

• Journal of Animal Environmental Science
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• v.16 no.3
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• pp.237-244
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• 2010

Using a vertical composting system in layer farms, the composting process was characterized in terms of temperature variation, change of moisture contents, fertilizer ingredient and so on. In this study, two types of layer farms were examined. The layer manure was produced as 3,300 and 116,650 kg/day for Farm A and Farm B, respectively. Also, their average moisture contents were 74.4% (Farm A) and 65.6 % (Farm B). The inside temperature of composting in Farm A was varied in the range of 50 to $70^{\circ}C$, and moisture content of it decreased from 59.5% to 20.6% at the edge of vertical composting system. While in Farm B, composting temperature was fluctuated between 50 and $65^{\circ}C$ and moisture content declined from 34.0% to 13.4% at the end of vertical composting system. The fertilizer ingredients such as T-N, $P_2O_5$ and $K_2O$ were not significantly influenced by seasonal effect. Their values were changed in the range of 0.90% to 0.47% for T-N, 0.16% to 0.42% for $P_2O_5$, and 0.22% to 0.28 for $K_2O$, respectively. Also, OM/N ratio was varied from 36.8 to 84.4.

• Journal of Life Science
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• v.19 no.10
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• pp.1451-1455
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• 2009

Porcine cytomegalovirus (PCMV) is a betaherpesvirus which causes reproductive failure in breeding sows and generalized infection in newborn piglets. It has worldwide distribution including Korea. Serological survey on this virus has been reported in 76.3% of pigs, but virological survey and epidemiological analysis on PCMV distribution have been reported in only a few papers in Korea. In this study, we investigated the virological prevalence and infection status of PCMV on a farm level in selected swine farms with respiratory diseases. A total of 1,938 blood samples taken from groups of pigs of different ages were collected from 31 farms distributed nationwide in 2006 and 2007 and tested by PCR to detect the presence of PCMV. Virological prevalence at farm level and pig level were 96.8% and 17.5%, respectively, suggesting that PCMV has endemically infected Korean pig herds. The prevalence at farm level in gilts, sows and suckling piglet groups were 16.7%, 36.7% and 56.7%, indicating that vertical infections frequently occurred in conception or newborn stage. Thereafter, detection rates of PCMV were slightly increased in pig groups aged 40 and 70 days (70.0% and 73.3%), and then gradually decreased as they aged - 33.3% in 100, 26.7% in 130 and 16.7% in 160 day old pig groups. The prevalence at pig level has similar patterns to that at farm level. With the passage of time, the variation of infection patterns of PCMV was investigated in four PCMV-positive farms. Three blood samples were collected at intervals of 6 months in each farm, and examined for presence of PCMV using PCR. The results revealed that once PCMV was introduced to the pig farms, it continuously circulated between and within groups of sows and piglets in those farms. Taken together, it can be concluded that PCMV has endemically infected Korean pig farms and has the potential risk for emerging pathogen in combination with the known endemic pathogens including porcine reproductive, respiratory syndrome virus and porcine circovirus type 2. Therefore, more research is needed on diagnosis, epidemiology and control strategy for PCMV on the field.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.139-145
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• 2000

The mechanism of the inner resistance in a rubber crawler system has been investigated to reduce the power requirement (Kitano et al. 1994). The rolling resistance of the track roller, which is one of the major inner resistances, was measured for seven different vertical loads. The rolling resistance changed periodically and could be classified into three types. In case of the vertical load less than 500N, the rolling resistance was almost constant. For the vertical load greater than 500N, the maximum value of the rolling resistance increased. Further more in case of the vertical load greater than 1200N, negative resistance appeared. Analytical simulation of the travel resistance based on experimental results and static equilibrium equations derived from three-dimension mechanical model for the rubber crawler system. It was found that the simulation method was carried out to evaluate the travel resistance occurred by the rolling resistance of the track roller. The rolling resistance for each track roller arrangement and effects of the lug phase in the right and left rubber crawler could be estimated quantitatively.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.2
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• pp.151-158
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• 2016

Tidal farm is a multi-arrayed turbine system for utilizing tidal stream energy. For horizontal-axis turbine(HAT) system, it is recommended that each unit has to be deployed far apart in order to avoid hydrodynamic interference among turbines, as proposed by the European Marine Energy Centre(EMEC). But there is no rule for the arrangement of vertical-axis turbine(VAT) yet. Moreover it has been reported that a proper arrangement of adjacent turbines can enhance the overall efficiency even greater than an arrangement without mutual interference effect. This paper suggests the layout of VATs showing the better performances, which turned out to be quite different from HATs' arrangement. Numerical calculations were performed to investigate the performance variation in terms of the rotational direction as well as the distance between turbines. It has been shown that the best combination of rotational direction and distance between turbines can increase its performance higher about 9.2% than that of two independently operated turbines. It is likely that such improvement is due to the increased velocity between adjacent turbines. For diagonally arranged turbines, the maximum normalized mean power coefficient was obtained to be higher about 5.6% than that of two independent turbines. It is expected that the present results can be utilized for conceptual design of tidal farm to harness the tidal stream energy.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.1
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• pp.30-39
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• 2004

In order to understand the environmental impact of marine cage fish farms, we measured the vertical fluxes of particulate to the sediment, the distribution of organic carbon in core samples, sediment oxygen consumption rate (SOD), and macrobenthos with increasing distance from a fish cage in Miruk island located in Tongyong. The experiment was performed in August 2003. Measured values gradually decreased with distance, indicating that the organic matter in the sediment derived from the fish farm. The dominant macrobenthos species were Tharyx mulifilis, Lumbrineris longifolia, Sigambra tentaculata, and Capitella capitata, occupying 88% of the total population. Capirella capirata, an opportunistic polychaete species, were especially abundant between 0 to 5 m radius range. The estimated impact regions of organic matter enrichment based on sediment consilmption rates and compositions of macrobenthos were in good agreement. Most organic matter derived from the fish farm was deposited within a 10 m radius and then dispersed horizontally to nearby (at least 50 m) surface sediment. The vertical organic carbon fluxes to the sediment at the fish farm were higher by a factor of two than those outside the area. The remineralization organic carbon in the upper sediment layer was estimated to be 50% (1.07 g C m$^{-2}$ day$^{-1}$ ) at the fish farm. In contrast, outside the area, 30% (0.30 g C m$^{-2}$ day$^{-1}$ ) of organic carbon was recycled and the remaining 70% was deposited to the deep sediment layer.

• Wind and Structures
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• v.36 no.3
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• pp.201-213
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• 2023

In this study, the effect of sea surface temperature (SST) on the distribution of vertical wind speed in the atmospheric boundary layer of coastal areas was analyzed. In general, coastal areas are known to be more susceptible to various meteorological factors than inland areas due to interannual changes in sea surface temperature. Therefore, the purpose of this study is to analyze the relationship between sea surface temperature (ERA5) and wind resource data based on the meteorological mast of Høvsøre, the test bed area of the onshore wind farm in the coastal area of Denmark. In addition, the possibility of coastal disasters caused by abnormal vertical wind shear due to changes in sea surface temperature was also analyzed. According to the analysis of the correlation between the wind resource data at met mast and the sea surface temperature by ERA5, the wind speed from the sea and the vertical wind shear are stronger than from the inland, and are vulnerable to seasonal sea surface temperature fluctuations. In particular, the abnormal vertical wind shear, in which only the lower wind speed was strengthened and appeared in the form of a nose, mainly appeared in winter when the atmosphere was near-neutral or stable, and all occurred when the wind blows from the sea. This phenomenon usually occurred when there was a sudden change in sea surface temperature within a short period of time.