• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.29 no.3
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• pp.200-213
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• 1993

A model experiment on a midwater rope trawl net which is used in the North Pacific to catch alaska pollack is carried out in the circulating tank to examine the basic efficiency of the net. The prototype is the net used by M/S Hanil(1, 179GT, 2, 700PS), a Korean trawler. The model net was made according to the Tauti's Similarity Law of Fishing Gear in 1/100 scale by considering the condition of the tank. To measure the basic efficiency of the standard model net, the vertical opening and width between some points marked on the net were measured, and the hydrodynamic resistance were determined. Then the constructive conditions of the net were varied as follows and the factors were measured again to compare the efficiency of those nets with that of the standard net(A-1 type) front weight multiplied 1.5 times: A-2 type. buoyancy and depressing force multiplied 1.7 times: A-3 type. front weight multiplied 1.5 times on A-3 type: A-4 type. depressors rigged at ground rope: B type. cod-end stuffed with cashmylon wad: C type. The results obtained can be summarized as follows: 1. The vertical opening at the center of head rope was steeply decreased with the flow velocity increasing and the vertical opening H(m) can be expressed in H=1.2v super(-1.2)(v : flow velocity in m/sec). The width of the net varied a little when the flow velocity was over 0.4m/sec, and the width of net mouth showed about 37% of the distance between the fore tips of net pendant. The shape of net mouth was almost a circle at 0.2m/sec and then steeply flatted elliptically with the flow velocity increasing and the area of mouth S(m super(2)) can be expressed in S=(1.65-2.3v)$\times$10 super(-2). The hydrodynamic resistance of the net increased almost linearly with the flow velocity increasing and the resistance R(kg) can be expressed in R=3.2$\times$d/l$\times$abv. where d/l denotes the mean of d(diameter of netting twine) and l(length of a leg in a mesh) from wing tip to the end of bag-net except cod-end on the side pannel, and a denotes the strectched circumference of the net at the fore end of a meshed part and b the stretched length of the whole net from wing tip to the end of cod-end. 2. In the condition-varied nets, the vertical opening of head rope showed some increase in every type net except the C type, and the increase showed the greatest in the B type by 30~54%, whereas it showed decrease in the C type by 5~10%. Variation of the area of net mouth showed almost the same tendency as the vertical opening and the increase showed the greatest in the B type by 20%, whereas it showed decrease in the C type by 12%. Hydrodynamic resistance showed some increase in every type compared with the standard net, and the rate of increase indicated 5~10% in the A-2, A-3 and A-4 type, 22% in the B type and 3% in the C type.

• Korean Journal of Medicinal Crop Science
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• v.20 no.5
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• pp.365-371
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• 2012

This study was carried out to know the characteristics of flowering and bearing fruit, the optimum period, regions and methods for seed harvesting, the optimum temperatures for seed storage and germination, and the optimum period for sowing at nursery bed and seedling transplanting of Valeriana fauriei Briquet. The flowering and bearing fruit of Valeriana fauriei was developed from the before-year root. Optimum period for seed harvest of Valeriana fauriei was from late July to middle August, and optimum areas were the high elevated areas over 500 m above the sea level as Jinbu-myeon, Pyeongchang-gun, Gangwon-do. Using of net-bag for seed harvesting was the effective method to gather the full ripe seed, and bagging of net-bag was necessary from the season of middle May that was the flowering middle-stage. Germination rates don't show the difference among the different temperatures of storage as approximately 41% at $-20^{\circ}C$, $2^{\circ}C$ or $20^{\circ}C$ of seed storage temperatures. The optimum temperature range was in $15{\sim}30^{\circ}C$ for seed germination at nursery bed. The optimum period for seed sowing at nursery bed was the late February, and the optimum period for seedling transplanting was the middle April.

• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.33-39
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• 2020

In the field of Natural Language Processing, Various research such as Translation, POS Tagging, Q&A, and Sentiment Analysis are globally being carried out. Sentiment Analysis shows high classification performance for English single-domain datasets by pretrained sentence embedding models. In this thesis, the classification performance is compared by Korean E-commerce online dataset with various domain attributes and 6 Neural-Net models are built as BOW (Bag Of Word), LSTM[1], Attention, CNN[2], ELMo[3], and BERT(KoBERT)[4]. It has been confirmed that the performance of pretrained sentence embedding models are higher than word embedding models. In addition, practical Neural-Net model composition is proposed after comparing classification performance on dataset with 17 categories. Furthermore, the way of compressing sentence embedding model is mentioned as future work, considering inference time against model capacity on real-time service.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.4
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• pp.61-69
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• 2002

This study was conducted to develop revegetation methods for the restoration of the steep slopes by seed attached ripping net revegetation methods. In general, steep slopes with decomposed granite soils and ripping rock are easy to erode by precipitation and impossible to revegetate only using hydroseeding with core net mulching because of poor soil fertility. The Seed Attached Ripping Net Revegetation Methods(SALNRM) will be the most popular and sustainable methods to restore decomposed granite soils and ripping rock exposed slopes. The main results are summarized as follows; 1. The net size with $1.5cm{\times}1.0cm$ density was more suitable for growing plants, and increasing the ratio of the slow release fertilizer was better to make early coverage and to grow germinated plants. 2. The fertilizer bag made by the ratio of Peatmose : Vermiculite : Perlite : Quick release fertilize r : Slow release fertilizer = 10 : 2 : 5 : 3 : 4 (v : v) was the best for plant's growth. 3. According to the seed mixture experiments, even though not using foreign grasses, the SALNRM using native plants can make diverse plant composition. 4. The SALNRM will make same early ground coverage by only using native plants like using foreign grasses. The SALNRM would become the popular revegetation methods to restore decomposed granite soils and ripping rock exposed slopes in Korea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.16 no.2
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• pp.55-59
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• 1980

The authors carried out a model experiment to compare the sinking speed and the tension of the purse line in two nets, made of knotted webbing (Model A) and Raschel webbing (Model B). The model net was made in 1/450 scale of the actual net being commercially used in the Korean coastal waters for mackerel. The headline of the model net is 200cm and the maximum height 50cm. The weight of the sinker in water was changed 4g and its multiplication till 20g. The results obtained are as follows: 1. Sinking speed of the model A was faster 1. 4 to 1. 8 times than that of model B. 2. Tension of the purse line of the model A was 10 to 20 percent less than that of model B.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.14 no.2
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• pp.57-62
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• 1978

When fisherman use the boat seine net to catch anchovy, a large noise (drum can, small drum and small gong) is used to scare the anchovy school along the wing nets, and into the bag net were they are caught. We want to know how much of an effect these s:mnds have on forceing the anchovy school towards the bag net. The underwater sounds of ancho\'y, drum can, small drum and small gong were analyzed in the labroatory. The behavioral responeses to the playback sounds of anchovy feeding and sounds of artificial instruments were also investigated. The feeding and artificial sounds of the samples were recorded by a tape recorder through a hydrophone in an anechoic aquarium. The sound intensity level was measured by means of a sound level meter in an anechoic chamber. The frequency and intensity of various sounds were analyzed with an analyzing system consisting of a ~-octave filter set, a high speed level recorder, an amplifier and an oscilloscope. The most successful recording was edited into a 9 to 10 second sound track and was repeated in a sequence of 9 to 10 second intervals. The sequence was then reproduced into an anechoic aquarium through the underwater speaker. The results of investigation are as follows; 1. The frequency of the feeding sound was 63~80Hz, and the pressure level produced was less than 32db. 2. The frequencies of the artificial sounds were 315~ 1,OOOHz, and the pressure levels were 88~95 db in the air. 3. When a hydrophone was placed 70cm below the surface with artificial sounds (drum can, small drum and small gong) produced 1 meter above the surface, the pressure level decreased about 30db. 4. The feeding sound was ineffective in attracting the anchovy, because of interference from ambient noise. 5. The artificial sounds had such a small effect on the anchovy's that they could not be used in ocean fisheries.

• Korean Journal of Ichthyology
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• v.13 no.1
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• pp.6-18
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• 2001

Larvae of the gunnel Pholis fangi were collected in coastal waters off Daecheon with a bag net from March to June, 1988, and with a ring larva net in February 1989. Maturity and spawning period were analyzed by examination of the gonads of adult fish collected with a bag net from May 1998 through November 1999. In February, the larvae were widely distributed in the outer and inner Cheonsu Bay. From March to April the larvae were present mainly the inner bay; they were absent there in May and found mainly in the outer bay. After June, few gunnel larvae were collected in the study area. This suggests a seaward movement of gunnel from the nursery grounds of the bay to offshore feeding grounds. The otolith of larvae smaller than 10 mm in total length did not show a distinct growth stop. The growth stop is believed to be formed in the early larval stage when the total length is about 10 mm. This period coincides with the time of shoreward migration, suggesting a metabolic change during this period. At a total length of 30 to 40 mm, the shape of the otolith changes from spherical to elongate. Daily growth rate in length was estimated by the Gompertz equation, which is represented as follows: TL = 6.702exp{2.925"1-exp (-0.008 t)"} ($r^2=0.94$, N = 92) Assuming daily deposition of growth increments in the otolith, the time of first growth increment formation was shown to be from December to January. Gonad observations show that Pholis fangi spawns from November to December. So, the hatching time is thought to be about one month.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.1
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• pp.1-9
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• 2021

Trawl fishing is a fishing method in which a large, motorized trawler tows a bag-shaped net to catch fish living at the bottom or middle layers. For a trawl gear, it is of utmost importance to select the gear size and towing speed suitable for the effective horsepower (EHP) of the trawler in the design stage. In general, the power required to move an object is proportional to the product of the object speed and resistance; therefore, there are various choices for the gear resistance and towing speed given the effective horsepower of the trawler. However, there have been few studies on the gear design of an appropriate scale for the towing speed given the effective horsepower of the trawler. In this study, the resistance and shape of three types of midwater trawl gears were analyzed using SimuTrawl, a computer simulation tool. In addition, the relationship between the propulsion force and speed of the ship was clarified when the size and effective horsepower of the trawler were determined. Finally, we suggested the relationship between the towing speed and the resistance of the gear when the trawler towed the net was investigated, and a specific method of selecting the gear size according to the towing speed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.4
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• pp.75-82
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• 1986

A field experiment was carried out to clarify the effect of underwater sound on the luring of fish school. The effects of. the acoustic emission on the luring of fish school were checked actually at a set net fishing site in Namhae using a commercial acoustic equipment, Dairyo-8. An emitting system of sound was designed by the authors, and the ambient noise, the sound pressure level and the reaction of fish school were measured in the set net. 1. The predominent frequency band of ambient noise was 150Hz-400Hz,.and the sound emitted was 400Hz-100Hz. The sound pressure level of ambient noise in set net was higher at the landing part, and lower at the playgrond, the gate of court and "the enterance of inclined "passage. The ambient noise was increased with the time elapse-d at the stage of hauling net, but :it was decreased suddenly at the final stage due probably to the decrease of the swimming speed of the fish school. 2. The results of the observation and the recording paper of echo sounder indicate that the effect of emitting sound in the bag net of set net was remarkable for the luring of fish school in the early stage, but decreased after 30 minutes. The reaction of fish school is more sensitiv2 to the sound pressure level than the time intervals between the emission and the pause. For the purpos~ of practical use, it is nesessary to confirm what kind of sound pressure level is the best for the luring of fish school. 3. In response to the acoustic equipment(Dairyo-8), fish school started to swarm 20 minutes after the sound emission and scattered when the sound paused. As the emitting pattern of the acoustic equiment, the three seconds of emission after one second of pause was more effective than the continuous emission at the set net fishing ground. Catch of the fish(s during th~ sound ernissio:l at the gate of court was three to five times more than that of no emission.

• Journal of Computing Science and Engineering
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• v.6 no.2
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• pp.143-150
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• 2012

Computational techniques for topic classification can support qualitative research by automatically applying labels in preparation for qualitative analyses. This paper presents an evaluation of supervised learning techniques applied to one such use case, namely, that of labeling emotions, instructions and information in suicide notes. We train a collection of one-versus-all binary support vector machine classifiers, using cost-sensitive learning to deal with class imbalance. The features investigated range from a simple bag-of-words and n-grams over stems, to information drawn from syntactic dependency analysis and WordNet synonym sets. The experimental results are complemented by an analysis of systematic errors in both the output of our system and the gold-standard annotations.