• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1075-1082
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• 2016

In order to calculate the optimum installation interval between a speed hump and hump type crosswalk that are installed continuously in succession, this study examined the speed of a vehicle that passes different intervals between speed humps and hump type crosswalks from the approach section of a roundabout having a maximum speed limit of 30km/h; analyzed the effects of speed humps and hump type crosswalks installed continuously in succession on vehicle driving speed; and simulated the optimum installation height of hump type crosswalk. As a result, the following conclusion was drawn. First, it was found that the optimum interval between a speed hump and hump type crosswalk, which are the representative traffic calming techniques for reducing vehicle speed, to control vehicle speed under 30km/h is 30m. Second, as a result of comparing the deceleration of a vehicle that pass hump type crosswalks, it was found that if the installation interval is 65 m and above, a speed hump and hump type crosswalk had no effect. Therefore, it is desirable that the maximum installation interval between a speed hump and hump type crosswalk for controlling vehicle speed within a fixed road section should not exceed 65m. Third, the analysis showed that the optimum installation height of hump type crosswalk is 6-8cm in case vehicle speed at the approach section is 20km/h or lower, 8-10cm in case of 30km/h, and 10cm in case of 30km/h or higher, respectively. Fourth, even at a road section on which a speed hump and hump type crosswalk are installed, speed reduction effects may sometimes be insignificant due to a driver's studying effect, traffic conditions and so on. Thus, it is judged that speed reduction effects will be greater if several traffic calming techniques such as speed hump, chicane, and choker are applied at the same time. Therefore, in case of applying traffic calming techniques for the purpose of reducing vehicle speed in order to promote pedestrian safety, the composite application of several techniques should be considered.

• Journal of Korean Society of Forest Science
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• v.80 no.3
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• pp.257-264
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• 1991

Korea has accomplished the afforestation of its forest land in the early 1980's. To meet the increasing demand for forest products and forest recreation, a development of scientific forest management system is needed as a whole. For this purpose the development of efficient forestfire management system is essential. In this context, the purpose of this study is to develop a theoretical foundation of forestfire danger rating system. In this study, it is hypothesized that the degree of forestfire risk is affected by Weather Factor and Man-Caused Risk Factor. (1) To accommodate the Weather Factor, a statistical model was estimated in which weather variables such as humidity, temperature, precipitation, wind velocity, duration of sunshine were included as independent variables and the probability of forestfire occurrence as dependent variable. (2) To account man-caused risk, historical data of forestfire occurrence was investigated. The contribution of man's activities make to risk was evaluated from three inputs. The first, potential risk class is a semipermanent number which ranks the man-caused fire potential of the individual protection unit relative to that of the other protection units. The second, the risk sources ratio, is that portion of the potential man-caused fire problem which can be charged to a specific cause. The third, daily activity level is that the fire control officer's estimate of how active each of these sources is, For each risk sources, evaluate its daily activity level ; the resulting number is the partial risk factor. Sum up the partial risk factors, one for each source, to get the unnormalized Man-Caused Risk. To make up the Man-Caused Risk, the partial risk factor and the unit's potential risk class were considered together. (3) At last, Fire occurrence index was formed fire danger rating estimation by the Weather Factors and the Man-Caused Risk Index were integrated to form the final Fire Occurrence Index.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.828-832
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• 2013

To report country-specific carbon and nitrogen stocks data in a pear orchard by Tier 3 approach of 2006 IPCC guidelines for national greenhouse gas inventories, an experimental pear orchard field of the Pear Research Station, National Institute of Horticultural & Herbal Science, Rural Development Administration, Naju, Korea ($35^{\circ}01^{\prime}27.70N$, $126^{\circ}44^{\prime}53.50^{\prime\prime}E$, 6 m altitude), where 15-year-old 'Niitaka' pear (Pyrus pyrifolia Nakai cv. Niitaka) trees were planted at a $5.0m{\times}3.0m$ spacing on a Tatura trellis system, was chosen to assess the total amount of carbon and nitrogen stocks stored in the trees and orchard soil profiles. At the sampling time (August 2012), three trees were uprooted, and separated into six fractions: trunk, main branches, lateral branches (including shoots), leaves, fruits, and roots. Soil samples were collected from 0 to 0.6 m depth at 0.1 m intervals at 0.5 m from the trunk. Dry mass per tree was 4.7 kg for trunk, 13.3 kg for main branches, 13.9 kg for lateral branches, 3.7 kg for leaves, 6.7 kg for fruits, and 14.1 kg for roots. Amounts of C and N per tree were respectively 2.3 and 0.02 kg for trunk, 6.4 and 0.07 kg for main branches, 6.4 and 0.09 kg for lateral branches, 6.5 and 0.07 kg for roots, 1.7 and 0.07 kg for leaves, and 3.2 and 0.03 kg for fruits. Carbon and nitrogen stocks stored between the soil surface and a depth of 60 cm were 138.29 and $13.31Mg{\cdot}ha^{-1}$, respectively, while those contained in pear trees were 17.66 and $0.23Mg{\cdot}ha^{-1}$ based on a tree density of 667 $trees{\cdot}ha^{-1}$. Overall, carbon and nitrogen stocks per hectare stored in a pear orchard were 155.95 and 13.54 Mg, respectively.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.1
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• pp.17-28
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• 2007

This study was conducted to analyze the optimum heading period according to the recent climatic change for improvement of rice yield and grain quality in the Yeongnam area. We analyzed climatic elements including daily mean air temperature, daily range of air temperature, sunshine hours, and amount of precipitation from 1996 to 2005 in comparison with those of the 1971 to 2000 normal. Daily mean air temperature and amount of precipitation in the recent 10 years increased, but daily range of air temperature and sunshine hours decreased in comparison with the norm. Also, monthly mean air temperature was lowered remarkably in July and August. The monthly amount of precipitation largely increased in August and September. The daily range of air temperature and sunshine hours were greatly decreased from August to October, Possible cultivation periods for rice in the recent 10 years ranged from 171 days in Boughwa to 228 days in Busan and was expanded about $1{\sim}13$ days in comparison with the normal. Optimum heading date by local regions for the maximum climatic yield potential was estimated as July 31 at Bonghwa to September 7 at Busan, Masan, and Tongyeong in the recent 10 years. There was a wide difference in optimum heading date according to local legions of the Yeongnam area. Compared to the normal, optimum heading date in the recent 10 years was delayed about I~8 days in most local regions except Bonghwa, Mungyeong, and Yeongdeok. These results suggested that it is necessary to develop late maturity rice cultivars for producing high yield and quality rice grain due to the recent climatic change. Moreover, it is still more important to select the most suitable cultivation period appropriate to the changed climate of each local region in Yeongnam area.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.9 no.3
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• pp.155-164
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• 1997

A comprehensive and systematic field monitoring program was initiated since October 1989, in order to investigate the temporal and spatial variation of shoreline position at northern part of Pea Island, North Carolina. Aerial photographs were taken every two months on the shoreline extending from the US Coast Guard Station at the northern end of Pea Island to a point 6 miles to the south. Aerial photographs taken were digitized initially to obtain the shoreline position data. in which a wet-dry line visible on the beach was used to identify the position of shoreline. Since the wet-dry line does not represent the “true" shoreline .position but includes the errors due to the variations of wave run-up heights and tidal elevations at the time the photos taken, it is required to eliminate the tide and wave runup effects from the initially digitized shoreline .position data. Runup heights on the beach and tidal elevations at the time the aerial photographs taken were estimated using tide data collected at the end of the FRF pier and wave data measured from wave-rider gage installed at 4 km offshore, respectively A runup formula by Hunt (1957) was used to compute the run-up heights on the beach from the given deepwater wave conditions. With shoreline position data corrected for .wave runup and tide, both spatial and temporal variations of the shoreline positions for the monitoring shoreline were analyzed by examining local differences in shoreline movement and their time dependent variability. Six years data of one-mile-average shoreline indicated that there was an apparent seasonal variation of shoreline, that is, progradation of shoreline at summer (August) and recession at winter (February) at Pea Island. which was unclear with the uncorrected shoreline position data. Determination of shoreline position from aerial photograph, without regard to the effects of wave runup and tide, can lead to mis-interpretation for the temporal and spatial variation of shoreline changes.nges.

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.289-297
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• 2005

This study was conducted to develop the suitable nutrient solutions for variable Cruciferae leafy vegetables. l/2, 1 and 3/2 strength of nutrient solution recommended by National Horticultural Research Institute were supplied to plants in deep flow technique systems during 25 days. The growth of pak-choi and leaf mustard 'Asia curled' was highest in the 3/2 strength, and kaie 'TBC' in the 1 strength. Mean cation ratio of nutrient solution for pak-choi, leaf mustard and kale was K $49.5\%$, Ca $35.8\%$ and Mg $14.7\%$, which was obtained by calculating the uptake rates of water and nutrients. Suitable composition of the nutrient solution for Cruciferae leafy vegetables was N 14, P 3, K 6.8, Ca 4.8, $Mg 2m{\cdot}L^{-1}$. To examine the suitability of nutrient solution developed for Cruciferae vegetables (NSC), plants were grown 4 times from Sep. 2003 to Oct. 2004. When plants were grown in NSC, relative growth rate increased 1.1 to 2.5 times and vitamin C content 1.06 to 1.52 times. The proper plants to apply NSC for functional leaf vegetable production were leaf mustard 'Asia recurled', 'Redcurled' and 'Pamagreen', kale 'TBC', 'Portugal' and 'Hanchu collard', leaf broccoli 'New green', pak-choi, baby cabbage 'Red king' and 'Green king', flowering red chinese cabbage and Korean cabbage.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.300-307
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• 2012

BACKGROUND: The Transfer Factor (TF) of heavy metals from soil to plant is important, because TF is an indicator of heavy metal in soils and a factor that quantifies bioavailability of heavy metals to agricultural products. This study was conducted to investigate the transfer ability of Arsenic (As), Cadmium (Cd), and Lead (Pb) from soil to agricultural products. METHODS AND RESULTS: We investigated heavy metals (As, Cd and Pb) concentrations in 9 agricultural products (rice, barely, corn, pulse, lettuce, pumpkin, apple, pear, tangerin) and soil. TF of agricultural products was evaluated based on total and HCl-extractable soil concentration of As, Cd, and Pb. Regression analysis was used to predict the relationship of total and HCl-extractable concentration with agricultural product contents of As, Cd, and Pb. The result showed that TF was investigated average 0.006~0.309 (As), 0.002~6.185 (Cd), 0.003~0.602 (Pb). The mean TF value was the highest as rice 0.309 in As, lettuce 6.185, pear 0.717, rice 0.308 in Cd, lettuce 0.602, pumpkin 0.536 in Pb which were dependent on the vegetable species and cereal is showed higher than fruit-vegetables in As. CONCLUSION(S): Soil HCl-extractable concentration of As, Cd, and Pb had the larger effects on thier contents in agricultural products than total soil concentrations. We suggests that TF are served as influential factor on the prediction of uptake. Further study for uptake and accumulation mechanism of toxic metals by agricultural products will be required to assess the human health risk and need TF of more agricultural products.

• Journal of Environmental Impact Assessment
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• v.25 no.3
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• pp.209-221
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• 2016

The section from water source to 2.6km upper stream of Hantan River is protected as the drinking water quality protection area according to guidelines of Ministry of Environment, because water source of the Gwanin water intake plant has been known the river. However, opinions were consistently brought up that the standard of water source protection zone must be changed with using underground water as water source because of contribution possibility of underground water as the water source of Gwanin water intake facility. In this regard, hydrogeologic investigation including resistivity survey and hydrogeochemical investigation were carried out to assess water source and infiltration of contaminant for the plant. Quaternary basaltic rocks (50m thick with four layers) covered most of the study area on the granite basement. As the result of the resistivity survey, it is revealed that permeable aquifer is distributed in the boundary of two layers: the basaltic layer with low resistivity; and the granite with high resistivity. Considering of outflow from Gwanin water intake facility, the area possessing underground water was estimated at least $5.7km^2$. The underground water recharged from Cheorwon plain was presumed to outflow along the surface of unconformity plane of basalt and granite. Based on field parameters and major dissolved constituents, groundwater and river water clearly distinguished and the spring water was similar to groundwater from the basaltic aquifer. Temporal variation of $SiO_2$, Mg, $NO_3$, and $SO_4$ concentrations indicated that spring water and nearby groundwater were originated from the basaltic aquifer and other groundwater from granitic aquifer. In conclusion, the spring of the Gwanin water intake plant was distinguished from river water in terms of hydrogeochemical characteristics and mainly contributed from the basaltic aquifer.

• Journal of Korea Port Economic Association
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• v.32 no.4
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• pp.149-163
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• 2016

Seafarers are an essential resource in maritime industries, which provide navigation skills, vessel maneuvering skills and fishing skills in the fishery industry. They also work as a driving force in pilotage, port operation, vessel traffic service, and marine safety. Other areas in maritime services, which rely on seafarer include safety management of ships, supervisory activities, and maritime accident assessment. In these ways, Korean seafarers have contributed to the growth of Korean economy. However, there have been issues of high separation rate, shortage of supply, multi-nationality, multiplicity of culture caused by employment of foreign seafarers, and aging. The present paper finds that maritime officers and fishery officers demonstrate differences in the statistics of on-board job taking and separation: the separation rate of fishery officers is higher than that of maritime officers. The existing data and statistics by the Korea Seafarer's Welfare & Employment Center could be improved by changing its structure from time series to panel data. The Korea Seafarer's Welfare & Employment Center is the ideal institution for collecting the panel data, as it has already accumulated and published relevant statistics regarding seafarer. The basic design method of the panel data is to adopt and improve it by including the information on ratings of maritime and fishery industries, ranks in a ship, personal information, family life, and career goal. Panel data are useful in short- and long-term forecasts of supply of Korean seafarers; demand evaluation of education, training, and reeducation of the seafarers; demographical dynamic analysis on Korean seafarers; inducement policy of long-term on board job taking in harmony with man-power demands in marine industries such as pilotage service; implementation of job attractiveness policy on Korean seafarers; and employment stabilization of Korean seafarers.

• Journal of Digital Convergence
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• v.9 no.6
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• pp.137-151
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• 2011

This dissertation aims to empirically analyze the effect of cultivation of software industry on the local economy through Inter-regional Software Input-Output Analysis. The temporal range of analysis of effect of software industry on the local economy shall be for the year 2005 since analysis is made on the basis of the Regional Industrial Input-Output Table published by the Bank of Korea in 2005, and spatial domain shall be limited to the 16 metropolitan cities and provinces, which are the standards for each administrative zone. Results of analysis of this dissertation are as follows. Firstly, average inverse matrix coefficient of software industry for each region was computed to be 1.6248, which is lower than the average inverse matrix coefficient of 1.7979 for the entire industries. Secondly, among these, inverse matrix coefficient of software industry for each region on other industry within the same region was 0.1794, which is higher than that of entire industries at 0.1382. However, average inverse matrix coefficients of software industry for each region on self-industry within the same region and entire industries in other regions were found to be 1.0119 and 0.4335, respectively, which is lower than those of entire industries at 1.0982 and 0.5616, respectively. Thirdly, domestic produces induced by final demand items of software industry for each region was the highest for Seoul with 17.3309 trillion Korean won, accounting for 81.0% of the total, followed by Gyeonggi with 2.3370 trillion Korean won, 10.9% of the total. Fourthly, distribution ratios of domestic produces induced by final demand items of software industry for each region were found to be 19.1%, 72.1% and 8.8% with respect to the weight of consumption, investment and export, respectively, thereby illustrating very high level of distribution ratios of domestic produces being induced by investment in comparison to the distribution ratios of domestic produces being induced for the entire industries at 47.3%, 19.8% and 32.9%, respectively.