• Journal of Korean Society of Forest Science
• /
• v.104 no.4
• /
• pp.632-639
• /
• 2015

Working in the forest would require a wide range of skills and experience for specific tasks which involve with a high level of risks to worker's safety. However, there has been a concern on the current standard wage system for forest workers because it does not effectively reflect the characteristics of typical working conditions in the forest. In addition, the current standard wages for forestry workers was estimated based on the construction industry's wage system. Therefore, the purpose of this study is to assess a current wage system through the mail survey method and to develop a new wage system for forest worker which effectively reflects skill sets and experience required for successful completion of the work in the forest. We mailed the survey questionnaire consisting of 19 questions to 659 forest workers and received 188 responses resulting in a 28.5% response rate. The results showed that the current average optimal wages of forest worker, special worker and feller were 97,680won/day, 127,559won/day and 152,403won/day, respectively though there were variations depending on the regions. In developing the new standard wage system, this study suggest the current work types(worker, special worker and feller) could be divided into 5 work types (forest-environment workers, forest operations in beginner, forest operations in intermediate, forest operations in advanced and forest equipment operator) reflecting specialty of forest operation thereby stabilizing the new wage system for forest workers.

• Journal of the Korean Chemical Society
• /
• v.8 no.3
• /
• pp.113-120
• /
• 1964

The critical examination of the spectrophotometric method for determining microgram quantities of phosphate by the n-butyl acetate extraction as molybdophosphoric acid and subsequent development of the molybdenum blue has been made. In this procedure from 2 to 8 ${\mu}g$. of phosphate-phosphorus can be determined under optimum conditions. The final concentration of ammonium molybdate and the final acidity of perchloric acid for the formation of heteropoly acid are suitable to be ranges of 0.5 to 1.1% and 0. 5 to 1. 1 N respectively, and subsequently extracted with 10 ml. of n-butyl acetate. The extract is developed to molybdenum blue with 5.0 ml. of 1. 3% stannous chloride in 1N hydrochloric acid. The color is stable for at least one hour in the use of perchloric acid for the condensation. In order to determination of submicrogram amounts of phosphate, the sensitivity of the molybdenum blue method is hardly sufficient, a sensitive and stable molybdenum(V)-thiocyanate complex method has been investigated. By the procedure less than 1.2 ${\mu}g$. of phosphate-phosphorus can be determined with an accuracy of less than 5% the relative error. The molybdenum(Ⅵ) extracted by the above procedure is reduced to molybdenum(V) in the extract directly with a solution of 4 to 10% of stannous chloride, 0.5 to 1.5 mM of copper, and 0.1 to 0.9 N of perchloric acid as final concentration in 4.3 to 6.3 N of hydrochloric acid or 9.0 to 13.0 N of sulfuric acid by heating for one minute in boiling water, after cooling, the molybdenum(V)-thiocyanate complex color is developed by adding 6.0 M ammonium thiocyanate solution making the final concentration to be in a range of 0.4 to 0.9 M. This procedure the very sensitive, reliable, and stable can be applied to determining submicrogram amounts of phosphate in natural waters with a precision of 1.6 ${\times}\;10^{-2}$ the standard deviation as absorbance.

• Journal of Aquaculture
• /
• v.13 no.2
• /
• pp.107-117
• /
• 2000

Optima for temperature, salinity and light intensity for Nitzschia closterium, Chlorella salina, I내초교냔 galbana and Tetraselmis subcordiformis, which are widely used in bivalve hatcheries of Shandong Province in China, were estimated. The temperature optimum was 23 $^{\circ}C$ for N. closterium and I. galbana and 25 and 27$^{\circ}C$ for C. salina and T. subcordiformis, respectively. That for salinity was 23${\textperthousand}$ for N. closterium and T, subcordiformis, but was 33${\textperthousand}$ for C. salina and I. galbana. In general, all the four microalgae grew faster under 6,000 lux than under 4,000 lux. Growth of N. closterium was faster at $25^{\circ}C$ and dropped abruptly >$25^{\circ}C$, and that of C. salina and T. subcordiformis progressively increased upto $25^{\circ}C$ but dropped beyond 27$^{\circ}C$. T. subcordiformis was the most eurythermal among the 4 species. For mass culture of microalgae in Korea, N. closterium and C. salina are suitable during spring and autumn but C. salina and I. galbana during summer. T. subcordiformis is suitable for culture throughout the year.

• Journal of Navigation and Port Research
• /
• v.38 no.5
• /
• pp.471-477
• /
• 2014

In general, a regular charterparty form is used as a charterparty for tugboats which are employed in marine construction and a bareboat charter form is generally used for barge boat charterparty. As the tug-barge charterparty which are currently used do not have a standardised form, contracting parties arbitrarily decide on the terms and conditions of the contract. As a result, provisions of the charterparty usually do not specify in the contract which party bears the burden of liability in case of accident. Furthermore, the terminologies used in the charterparty are different from legal terms of current commercial law which causes confusion. These problems can be solved mostly by clarifying the legal character of the charterparty between the contracting parties and by conforming the terminologies. In addition, endeavour to standardise the contract form must be carried forward at the same time. This research purports to study actual condition of current charterparty for tug-barge ship which are employed to marine construction and to suggest systematic improvement plan. For this purpose, this research focuses on studying cases in which dispute arose due to lack of clarity in the provisions of the contract with regard to which party bears the burden of liability in case of accident. This research also purports to suggest forming the standardised contract terms of the charterparty as one way of solution and examine matters to be attended in writing a standardised form.

• Ecology and Resilient Infrastructure
• /
• v.1 no.2
• /
• pp.49-60
• /
• 2014

Fish assemblages play an integral role in stream ecosystem and are influenced by stream environmental conditions and habitat disturbances. Fish community structures and habitat parameters of U.S. EPA rapid bio-assessment protocol were surveyed to investigate the effect of stream environment and habitat disturbance on fish communities at 13 study sites in the Gapyeong Stream, a typical gravel-bed stream. Principal component analysis (PCA) based on data from habitat assessment at each study site indicated that the study sites were differentiated by habitat parameters such as embeddedness, velocity/depth regime and sediment deposition, which were related with bed slope. A total of 46 species belonging to 12 families were collected in the Gapyeong Stream. A dominant species was Zacco koreanus, subdominant species was Z. platypus. Hierarchical cluster analysis based on species abundance classified fish communities into the three main groups along the stream longitudinal change. Non-metric multidimensional scaling (NMDS) portrayed that fish community structures were related to major habitat parameters, i.e., epifaunal substrate/available cover, embeddedness, velocity/depth regime, sediment deposition, channel alternation and frequency of riffles. These results suggested that fish community structures were primary affected by the longitudinal environmental changes, and those were modified by habitat disturbance in the Gapyeong Stream, a gravel-bed stream.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.24 no.5
• /
• pp.343-351
• /
• 2012

In this study, shallow-water design waves are calculated for the return period of 10, 20, 30, and 50 years, based on the extreme value analysis of the wave measurement data at Gangneung beach. These values are compared with the results of SWAN simulation with the boundary condition of the deep-water design waves of the corresponding return periods at the Gangneung sea area provided by the Fisheries Agency (FA, 1988) and Korea Ocean Research & Development Institute (KORDI, 2005). It is found that the shallow-water wave heights at Gangneung beach calculated by the deep-water design waves were significantly less than the observation data. As the return period becomes higher, the significant wave heights obtained by the extreme value analysis becomes higher than those computed by SWAN with the deep-water design waves of the corresponding return periods. KORDI computed the hindcast wave data from January 2004 to August 2008 by WAM with a finer-grid mesh system than those of previous studies. Comparisons of the wave hindcast results with the wave observation show that the reproducibility of the winter-season storm wave was considerably improved compared to the hindcast data from 1979 to 2003. Hereafter, it is necessary to carry out hindcast wave data for the years before 2004 using WAM with the finer-grid mesh system and to supplement the deep-water design wave.

• Journal of Wetlands Research
• /
• v.8 no.3
• /
• pp.29-38
• /
• 2006

Digital Elevation Model (DEM) of intertidal flat can be widely used not only for scientific fields, coastal management, fisheries, ocean safety, military, but also for understanding natural and artificial topographic changes of the tidal flat. In this study, we generated DEM of the Ganghwado southern intertidal flat, the largest tidal flat in the west coast of the Korean Peninsula, using waterline method and interferometric synthetic aperture radar (InSAR). Constructed DEM which applied waterline method to the Landsat-5 TM and Landsat-7 ETM+ images closely expresses overall topographic relief of tidal flat. We found that the accuracy was determined by the number of waterlines which reflect various tidal conditions. The application of InSAR to the ERS-1/2 and ENVISAT images showed that only ERS-1/2 tandem pairs successfully generated DEM in the part of northern Yeongjongdo, but construction of DEM in the other areas was difficult due to the low coherence caused by a lot of surface remnant waters. In the near future, Kompsat-2 will provide satellite images having multi-spectral and high spatial resolution within a relatively short period at different sea levels. Application of waterline method to these images will help us construct a high precision tidal flat DEM. Also, we should develop DEM generation method using single-pass microwave satellite images.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.19 no.4
• /
• pp.256-264
• /
• 2014

This study was carried out to estimate the benthic environments and polychaetous community in Garolim Bay, through five field surveys from April 2006 to April 2007. Garilim Bay is a semi-enclosed bay and composed of a biramous tidal channel and nearby wide tidal flats. Surface sediment in the inner bay was composed of fine grained particles whereas that in the mouth area of bay was of coarse grained ones. Benthic polychaete worms were the most dominant taxa occupying 65.1% of total benthic macrofauna. Species number was higher in the inner bay than mouth and outer area of bay, and in the bay higher on the tidal flat than channel area. Density was higher on the tidal flat than channel area. Dominant polychaetous species were Prionospio sp., Heteromastus filiformis, Lumbrineris longifolia and so on, which is known as opportunistic species. Prionospio sp. and H. filiformis inhabited mainly on the tidal flats in inner bay, while L. longifolia in the channel area and mouth of the bay. Cluster analysis and nMDS showed the typical inner-to-outward distribution of station groups, which indicated the sequential difference of the species composition of each station group. To assess the benthic healthiness of Garolim Bay by AMBI and BPI analysis, the benthic condition was analyzed from slightly polluted in the outer and mouth of the bay to moderately polluted in the inner bay. Assumed from dominant species composition and benthic healthiness condition, benthic environments of Garolim Bay was slightly unstable and disturbed and organic enrichment was currently underway by massed fisheries farms.

• Journal of fish pathology
• /
• v.31 no.1
• /
• pp.9-13
• /
• 2018

We previously monitored nervous necrosis virus (NNV) in brain samples of artificially produced walleye Pollock (Gadus chalcogrammus) seedlings, with a low prevalence (1.8%, 1/55) but no clinical symptoms. Given that this virus is considered one of the most serious viral threats for almost all marine aquaculture fish species and characterized by both vertical and horizontal transmission, it would be interesting to monitor NNV in the fertilized eggs as well. We collected fertilized walleye pollock eggs from the farms located in Goseong during January to March, 2017. Approximately 50 mg of eggs were periodically taken from 4 each different batches, and 37 different pooled sample sets in total were made during sampling period. RNA was extracted from the eggs by using Trizol and cDNA was synthesized for RT-PCR for detecting NNV. Primers and PCR conditions are the same as previously described. As a result, NNV was not detected from any of the sample sets by one step PCR (0%, 0/37), suggesting NNV may not be a threat in walleye pollock aquaculture in Korea at present time. However, continuous monitoring for NNV should be conducted because introducing a new species into aquaculture industry involves potentials of disease outbreak and NNV is already known to cause outbreaks in gadoid fishes.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.11
• /
• pp.568-573
• /
• 2018

UAV(Unmanned Aerial Vehicle) is widely used in space information construction, agriculture, fisheries, weather observation, communication, and entertainment fields because they are cheaper and easier to operate than manned aircraft. In particular, UAV have attracted much attention due to the speed and cost of data acquisition in the field of spatial information construction. However, ortho image images produced using UAVs are distorted in buildings and forests. It is necessary to solve these problems in order to utilize the geospatial information field. In this study, fixed wing, rotary wing, vertical take off and landing type UAV were used to detect distortions of ortho image of UAV under various conditions, and various object areas such as construction site, urban area, and forest area were captured and analysed. Through the research, it was found that the redundancy of the unmanned aerial vehicle image is the biggest factor of the distortion phenomenon, and the higher the flight altitude, the less the distortion phenomenon. We also proposed a method to reduce distortion of orthoimage by lowering the resolution of original image using DTM (Digital Terrain Model) to improve distortion. Future high-quality unmanned aerial vehicles without distortions will contribute greatly to the application of UAV in the field of precision surveying.