• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.459-466
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• 2013

To understand the fishery characteristics by a beam trawl off the coast of the Chungnam province, covering $125^{\circ}$ 50'~$126^{\circ}$ 05'E, $36^{\circ}$ 15'~$36^{\circ}$ 25'N, a beam trawl was deployed 2~4 times a month from March 2008 to February 2009. The catch was consisted of 96 species of 63 families belonging to 19 orders. Among these, organisms were identified as 54 species of fish, 27 species of crustaceans, 9 species of gastropoda, bivalves, and 6 species of cephalopods. Trachysalambria curvirostris which is the target species of the beam trawl fishery occupied only 2.1% of the total catch, showing a low ratio of catches. Most of T. curvirostris was harvested from July to November while small amount of T. curvirostris was captured from May to December. In this study, we concluded that the bycatch ratio except T. curvirostris in T. curvirostris fishery was relatively high, thus the fishery of T. curvirostris might affect the fishery resource management of bycaught species off the coast of Chungnam province.

• Journal of the Korean Society of Food Culture
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• v.4 no.1
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• pp.83-94
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• 1989

A secondary survey was conducted of 503 customers, to investigate eating out behaviours at five fast food restaurants of Youido apartment compound in Seoul, in April of 1988. The results are summarized as follows: The majority, 84% of customers, were aged 14 to 30, consisting of junior and senior high school children, college students and company employees. In contrast to the previous survey of 1986, in which no elderly customers were found, a small number of elderly customers were observed in this study. The reasons given by customers for patronizing fast food restaurants were the following, from most to least frequent: 'convenient', 'allows for companionship', 'the pleasant place to eat', 'dining equipment and tableware are hygienic', 'to be able to stay as long as I want', and 'foods rapidly served'. Only 24.2% of the customers purchased the fast foods for a full meal, 38.3% purchased the foods for snacking, and others purchased ice cream only or drink only. The majority of the customers ate the purchased foods at the fast food restaurants. However, a limited number of female customers preferred to take the packed fast foods to their homes. Taste preference was a major factor in food selection from available menu items, among the younger customers; whereas customers over 30 years old were concerned with nutritive balance. Fried chicken, pizza, rolled rice with laver, ice cream, and juice were high on the list of liked foods; in contrast, lower preference was for fish burger, doughnut, spaghetti, Chajang noodles and chili beans. The survey discovered that the preference for fried chicken, pizza, and salad had increased compared to the previous survey of 1986. Preference by food nationality was highest for Korean food, then Western food, Chinese food, and Japanese food, in that order. Customers offered suggestions for better fast food service, such as lowering the price; greater variety in the menu; developing fast foods from the traditional Korean foods; and increasing the proportion of vegetables and fruits on the fast food menu. The customers, in particular, emphasized a need for the development of Korean traditional beverage of malt drink and persimmon punch, as well as mungbean pan cakes and sweet- spicy rice noodles (docbokki), as fast foods.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.6
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• pp.329-333
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• 2016

Disinfection by electrolysis would be useful for small wastewater treatment plant, combined sewer overflow, ballast water, swimming pool, and fish farming, where the transport, storage, and the use of chlorine gas is limited. This study investigated the feasibility of the electrolysis of dilute hydrochloric acid (HCl) for disinfection. The effects of HCl concentration, voltage and reaction time on the generation of oxidizing agents, HOCl, $O_3$, and $H_2O_2$, were examined in a series of batch test. The highest current efficiency was 99.3% which was found at 2.2%, 3 V, and 5 min of HCl concentration, voltage, and reaction time, respectively. Continuous electrolysis at 2.2% HCl, 3 V, and 5 min of the hydraulic retention time showed 97.4% of the current efficiency. Addition of sodium chloride up to 20 g/L linearly increased the oxidizing agents production. 92.2% of total coliforms were removed by the contact with the electrolyzed water.

• Journal of Nutrition and Health
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• v.46 no.2
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• pp.186-196
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• 2013

The objective of this study was to develop a semi-quantitative food frequency questionnaire (FFQ) for an adult population for use in the Korea National Health and Nutrition Examination Survey (KNHANES). The 24-hour recall data for 2,939 subjects aged 19 years and over from the fourth KNHANES first year (2007) were used to extract the items included in the questionnaire. The FFQ items were developed by selection of major dishes based on the cumulative contribution rate, between-person variability based on the cumulative R2 of energy and 14 nutrients (carbohydrate, protein, fat, crude fiber, calcium, phosphorous, iron, sodium, potassium, vitamin A, thiamin, riboflavin, niacin, and vitamin C) and the number of consumers of each dish. In addition, the FFQ items were revised with analysis of 24-hour recall data of the fourth KNHANES second and third year (2008, 2009). Finally, 112 items were included in the FFQ and grouped as follows: rice (5 items), noodles and dumplings (6), breads and rice cakes (8), soups and stews (12), soybeans, eggs, meat and fish (23), vegetables, seaweed and potatoes (27), milk and dairy products (4), fruits (13), beverages (5), snacks (6) and alcoholic beverages (3). The food items of FFQ accounted for an average of 87.0% of energy and 14 nutrient intakes and also accounted for 81.7% of the between-person variability. The frequency range of the FFQ items was classified into nine categories (never or seldom, once per month, 2-3 times per month, once per week, 2-4 times per week, 5-6 times per week, once per day, twice per day and three times per day) and the portion size was divided into three categories (small, medium and large). We expect that this developed dish-based FFQ could be used in assessment of longterm dietary intakes of Korean adults.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.593-600
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• 1999

The survival rates of Littorina brevicula exposed to experimental concentration regimes of TBTCl, HB and Cd on the large and the small size individuals during 80 days were $80\%$ at 0,9ppb TBTCl, 40 and $25\%$, respectively at 200ppb Hg, and 75 and $45\%$, respectively at 100ppb Cd. The growth rates of the experimental animals exposed to each concentration for 80 days was 0.023mm/day at control, 0.019mm/day at 0.1ppb and 0.014mm/day at 0.9ppb TBTCl, 0.022 mm/day at 5ppb, 0.008 mm/day at 200ppb Hg, and 0.017 mm/day at 5ppb, 0.008mm/day at 100ppb Cd. The respiration rates and excretion rates of the experimental animals exposed to chronic concentration of TBTCl, Hg and Cd were decreased until approximatively 40 days and increased after, Toxic effect of pollutants on L. brevicula was highest at TBTCl. The histological injury of L. brevicula exposed to TBTCl, Hg and Cd was shown at gill, digestive organ and muscle, respectively.

• Journal of Environmental Health Sciences
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• v.45 no.2
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• pp.192-202
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• 2019

Objectives: According to the central limit theorem, the samples in population might be considered to follow normal distribution if a large number of samples are available. Once we assume that toxicity dataset follow normal distribution, we can treat and process data statistically to calculate genus or species mean value with standard deviation. However, little is known and only limited studies are conducted to investigate whether toxicity dataset follows normal distribution or not. Therefore, the purpose of study is to evaluate the generally accepted normality hypothesis of aquatic toxicity dataset Methods: We selected the 8 chemicals, which consist of 4 organic and 4 inorganic chemical compounds considering data availability for the development of species sensitivity distribution. Toxicity data were collected at the US EPA ECOTOX Knowledgebase by simple search with target chemicals. Toxicity data were re-arranged to a proper format based on the endpoint and test duration, where we conducted normality test according to the Shapiro-Wilk test. Also we investigated the degree of normality by simple log transformation of toxicity data Results: Despite of the central limit theorem, only one large dataset (n>25) follow normal distribution out of 25 large dataset. By log transforming, more 7 large dataset show normality. As a result of normality test on small dataset (n<25), log transformation of toxicity value generally increases normality. Both organic and inorganic chemicals show normality growth for 26 species and 30 species, respectively. Those 56 species shows normality growth by log transformation in the taxonomic groups such as amphibian (1), crustacean (21), fish (22), insect (5), rotifer (2), and worm (5). In contrast, mollusca shows normality decrease at 1 species out of 23 that originally show normality. Conclusions: The normality of large toxicity dataset was not always satisfactory to the central limit theorem. Normality of those data could be improved through log transformation. Therefore, care should be taken when using toxicity data to induce, for example, mean value for risk assessment.

• Korean Journal of Ichthyology
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• v.33 no.1
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• pp.8-14
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• 2021

Spawning behavior of the endangered Korean fish, Microphysogobio koreensis, was investigated in the Seomjingang (river), Imsil-gun, South Korea, during the spawning season, April to May 2012. The mating system of M. koreensis, a broadcast spawner, was a primitive spawning mode, and involved one male and one female, unlike group spawning fishes. Spawning behavior of M. koreensis in the wild were observed in eight patterns as resting, male chase, body beating, parallel swim, female withdrawal, male competition, spawning and not guard while spawning behavior in the glass tank were verified in six patterns as resting, male chase, body beating, parallel swim, spawning and not guard. In particular, a behavioral attempt of the pre-spawning stage showed more frequently in the wild than in the glass tank. We assume that difference of spawning behavior might be implication on behavioral restrictions in small and narrow indoor glass tank.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.2
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• pp.139-146
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• 2023

Maritime object detection systems, which detects small maritime obstacles such as fish farm buoys and visualizes distance and direction, is equipped with a 3-axis gimbal to compensate for errors caused by hull motion, but there is a limit to distance error corrections necessitated by the vertical movement of the camera and the maritime object due to wave motions. Therefore, in this study, the distance error of maritime object detection systems caused by the movement of the water surface according to the external environment is analyzed and corrected using average filter and moving average filter. Random numbers following a Gaussian standard normal distribution were added to or subtracted from the image coordinates to reproduce the rise or fall of the buoy under irregular waves. The distance calculated according to the change of image coordinates, the predicted distance through the average filter and the moving average filter, and the actual distance measured by laser distance meter were compared. In phases 1 and 2, the error rate increased to a maximum of 98.5% due to the changes of image coordinates due to irregular waves, but the error rate decreased to 16.3% with the moving average filter. This error correction capability was better than with the average filter, but there was a limit due to failure to respond to the distance change. Therefore, it is considered that use of the moving average filter to correct the distance error of the maritime object detection system will enhance responses to the real-time distance change and greatly improve the error rate.

• Korean Journal of Ichthyology
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• v.35 no.1
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• pp.30-38
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• 2023

The feeding ecology of the eight barbel loach, Lefua costata, were investigated in the Jusucheon (Stream), Namyang-ri, Okgye-myeon, Gangneung-si, Gangwon-do, Korea from January to December 2013. L. costata mainly fed from March to December when the water temperature was higher than 5℃, and the feeding rate peaked in April~May and September~October. Their main food organisms analyzed by the index of relative importance (IRI) were Diptera (77.1%), Ephemeroptera (20.3%), Trichoptera (1.7%) and Odonata (0.4%) in Insecta. Other food organisms were various, such as Arhynchobdellida (0.6%) and Tubificida (0.1%) of Annelida, Nematoda (0.2%), fish (Actinopterygii, 0.1%), and Veneroida (0.01%) of the Mollusca. Major seasonal food organisms were Diptera (55.4%) and Ephemeroptera (41.6%) in spring, Diptera (92.7%) and Anelida (6.8%) in summer, Diptera (70.8%), Ephemeroptera (9.0%), Trichoptera (8.1%) and Annelida (7.7%) in autumn. By age, juvenile (0+) tended to eat only Diptera (mainly Chironomidae, 98.2%) that were relatively small in prey size. However, as it grew, the proportion of Diptera gradually decreased, and the proportion of relatively large Mayflies and Annelids increased. The size of the prey organisms showed rapid growth, with 2.5±1.05 mm for juvenile (0+), 3.2±1.29 mm for one year (1+), 3.7±2.05 mm for two years (2+), and 6.8±4.97 mm for three years or more (≥3+).

• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.278-284
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• 2023

The feeding characteristics of chub mackerel, Scomber japonicus was studied using 827 specimens caught in the Yellow Sea of Korea during Autumn season from October to December 2021 and September to November 2022. The size of the specimens ranged from 21.1 to 45.1 cm in total length. S. japonicus was a carnivore that consumed mainly on fishes, such as Engraulis japonicus (%IRI=67.9). Its diet also includes small quantities of copepods, amphipods, euphausiids, cephalopods, mysids, shrimps, and crabs, etc. The estimated trophic level of S. japonicus was 3.84. The proportion of fish had increased as the body size of S. japonicus increased, whereas those of euphausiids, copepods and amphipods decreased gradually. As the body size of S. japonicus increased, the mean weight of prey per the stomach (mW/ST) tended to increase (One-way ANOVA, F=2.382, P<0.05).