• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.4
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• pp.423-430
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• 2011

The most satisfactory split-beam transducer for fish sizing maintains a wide bearing angle region for correct fish tracking without interference from side lobes and lower sensitivity to fish echoes outside of the main lobe region to correctly measure the angular location of free-swimming fishes in the sound beam. To evaluate the performance of an experimentally developed 50 kHz split-beam transducer, the angular location of a target was derived from the electrical phase difference between the resultant signals for the pair of transducer quadrants in the horizontal and vertical planes consisting of 32 transducer elements. The electrical phase difference was calculated by cross-spectral density analysis for the signals from the pair of receiving transducer quadrants, and the directivity correction factor for a developed split-beam transducer was estimated as the fourth-order polynomial of the off-axis beam angle for the angular location of the target. The experimental results demonstrate that the distance between the acoustic centers for the pair of receiving transducer quadrants can be controlled to less than one wavelength by optimization with amplitude-weighting transformers, and a smaller center spacing provides a range of greater angular location for tracking of a fish target. In particular, a side lobe level of -25.2 dB and an intercenter spacing of $0.96\lambda$($\lambda$= wavelength) obtained in this study suggest that the angular location of fish targets distributing within a range of approximately ${\pm}28^{\circ}$ without interference from side lobes can be measured.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.25 no.4
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• pp.191-199
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• 1989

Research on the acoustic properties of fish has been carried out by a number of scientific workers from the earliest days of applying acoustic techniques to fish biomass estimates. This paper describes measurements of the target strength of Cyprinus Carpio, which measurements made at 50KHz in the experimental water tank. The results obtained are as follows: 1. The target strength(dB) of the fish has a directivity pattern quite similar to that of a transducer. The maximum value of target strength(dB) is obtained when the fish is insonified to its head-tail axis either from the dorsal or from the ventral side. 2. Empirical relationship between target strength(dB) and body length(cm) of the fish can be estimated as TS=20 Log L-65.4 where TS is the target strength of the fish and L is the body length of the fish. 3. The relationship between target strength(dB) and body weight(g) of the fish can be estimated as TS=6.7 Log W-53.7 where W is body weight of the fish.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.2
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• pp.155-158
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• 1996

Seventy two Black Bengal goats on road side grass based diet were fed on 0, 20, 40, 80, 100 or 120 g of fish meal (FM)/goat/day with or without ad libitum access to urea molasses block(UMB). The purpose was to assess the interaction of undegradable protein (UDP) and fermentable nitrogen(N) supplementation on feed intake, nutrient digestibility and growth of goats. Live weight gain of goats increased linearly with the increasing of dietary fish meal as an undegradable protein source. With the increasing level of fish meal the live weight gain(g/day) was 17, 23, 46, 48, 48 and 52 with urea molasses block and 12, 21, 31, 49, 47 and 47 without urea molasses block. It was concluded that the beneficial effects of urea molasses feeding to accelerate the dry matter intake, TDN intake and nutrient digestibility observed could not be exploited in terms of live weight gain.

• Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.123-129
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• 2011

To determine whether rearing density affects the hypermelanosis on the blind side (ambicoloration) of olive flounders Paralichthys olivaceus, we reared fry with an unpigmented non-eyed (blind) side in duplicate at densities of 150 individuals/$m^2$ (commercial production density: control) and 450 individuals/$m^2$ (high density group) for 90 days in 1-t dark-green fiberglass reinforced plastics (FRP) tank. We recorded feed intake, feed conversion efficiency (FE), growth and survival, and measured the ratios of staining blind-side area (staining area) and ambicolored fish every 30 days. Daily feed intake (DFI), feed conversion efficiency (FE), growth rate, condition factors, and survival rate were calculated at the end of the experiment. Although the FE was higher in the high-density compared to the control, the two density groups showed similar feed intakes, growth, and survival. The ratio of staining area as well as the ratio of ambicolored fish significantly were significantly higher in the high-density group than in the control from days 30 to 60, but significantly increased and evened out by the end of the experiment (P<0.05). In conclusion, we determined that rearing density is not the main cause of the blind-side hypermelanosis, but found that increasing the rearing density can accelerate the ambicoloration in olive flounders.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.4
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• pp.413-422
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• 2011

An improved split-beam transducer for a 50 kHz fish-sizing echo sounder was developed. The main objective of this study was to minimize the side lobe level in the beam pattern and the distance between acoustic centers for adjacent transducer quadrants in the geometrical arrangement of array elements while maintaining a given number of transducer elements and beam width. To achieve these goals, a 32-element planar array transducer ($6{\times}6$ array with one element in each corner missing) was designed using the Dolph-Chebyshev shading function to suppress side lobes in the array beam pattern and fabricated by arranging the inter-element spacing to be substantially equal to half the wavelength using the transducer element of 0.4 times the wavelength in diameter. The performance characteristics of this split-beam transducer were evaluated in the experimental water tank of $5m{\times}5m{\times}6m$ (length${\times}$height${\times}$width). In this study, the design goal of the beam width and side lobe level for transmitting a beam pattern was initially set at $21^{\circ}$ and -30 dB, respectively. However, the measured beam width at 3 dB was $21^{\circ}$ in both directions with side lobe levels of -24.7 dB in the horizontal plane and -25.6 dB in the vertical plane. The averaged beam width at -3 dB of the receiving beam patterns for four receiving quadrants was $31.4^{\circ}$. The transmitting voltage response was 161.5 dB (re $1{\mu}Pa$/V at 1 m) at 50.23 kHz with a bandwidth of 2.16 kHz, and the averaged receiving sensitivity for four receiving quadrants was -178.13 dB (re 1 V/${\mu}Pa$) at 49.8 kHz with a bandwidth of 2.64 kHz.

• Journal of Nutrition and Health
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• v.17 no.1
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• pp.10-19
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• 1984

The Purpose of this study was to investigate the food preferences of college students of Korea. The survey was conducted on november, 1981 through the questionnaires. The subjects were 1184 male and 1241 female students of 9 universities. The results obtained were summarized as follows : 1) Preferences of staple foods : Cooked rice was preferred most by the subjects. Male liked rice more than female, whereas female liked bread and noodle more than male. Among the different kinds of rice, bread, and noodles, the following food items were favored by the subjects. (plain rice, red bean rice and soybean rice ; salad bread and vegetable bread ; Nangmyun and Bibim Kooksu). The foods not preferred were barley rice, instant noodle and soybean milk noodle. 2) Preference of side - dishes : Among the kinds of side - dishes by different preparation methods, stews were the most favored and the next favored were soups by the subiecls whereas female showed lower preference of soups than male subjects Most disliked kinds of side-dishes were changachi and moochim. For example, side-dishes which showed higher preference in each preparation method were stew (Kimchi stew and Soybean paste stew), soup (Beef soup and Seaweed soup), kimchi (Korean cabbage Kimchi), Bockeum (Sauted beef and Sauted Kimchil, cheon(Beef Cheon, fish Cheon), Kui(broiled saury and broiled yellow tail runner), Chorim(braised cuttle fish and braised fish cake), Namul(sliced radish, cucumber, and spinachi), and Changachi (dried radish). The side-dishes which showed lower preference were Alaskan pollack soup, soybean curd residue stew, cabbage Kimchi, liver Cheon, sauted liver, hairtail Chorim, radish rootNamul, and dried radish root Changachi. 3) Preferences of snacks. Fruits apple, peach, pear) were the most preferred snacks by the subjects. Male preferred ginsang tea whereas famale preferred coffee. Both bate and female subjects showed higher preference of milk and lower preference of sweets. 4) Preference of one-dish meals : No one dish meal were disliked by the subjects. Male liked Bockeum-Bab more than female, and female liked Mandukuk more than male subjects.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.3
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• pp.841-847
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• 2016

To study the influence of background color and substratum on hypermelanosis of starry flounder, we compared the daily food intake (DFI), the feed efficiency (FE), the survival, the growth, the ratio of pigmented area on the blind side and the ratio of hypermelanic fish duplicately reared for 180 days in dark-green FRP aquarium (control), white FRP aquarium together with dark-green substratum. The ratio of pigmented area on the blind side was significantly higher at the dark-green group than at the white group. DFI, FE and growth were higher in the dark-green substratum. Pigmented area rate and ratio of hypermelanic fish were significantly higher at the dark green group than at the high dark-green substratum. The results suggest that bright tank color and substratum bottom could inhibit the hypermelanosis.

• Korean Journal of Community Nutrition
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• v.14 no.4
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• pp.392-405
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• 2009

This study was conducted to investigate food and meal preference of workers (435 male and 212 female) in the Chonnam Yeosu industrial area. The results of the survey were analyzed by principal components analysis. The results were obtained as follows: 19.3% of the subjects were twenties, 28.3% were thirties, 28.8% were forties and 23.7% were fifties. Females liked rice rolled in dried laver, rice cakes, janchi-noodle and breads, on the other hand males liked thick beef soup, loach soup, an eel stew and soju. The young liked instant noodles, fried chicken, sweet and sour pork, pork cutlet, pizza, hamburger, ham, sausage and fruit beverage, on the other hand the old liked a fish pot stew, loach soup, eel stew, fish boiled in soy with spices, panfried fish, sea slug, ascidian, bunder, green laver and boiled burdock-lotus root in soy. Females who are young liked hamburger and sweet and sour pork whereas males who are young liked instant noodles, pork cutlet, ham, sausage and fruit beverage. Aged females liked fish boiled in soy with spices, panfried fish, bunder, green laver, boiled burdock-lotus root in soy whereas aged males liked a fish pot stew, loach soup, eel stew, sea mussel and oysters. Boiled rice was located within the middle irrespective of age and sex, but noodles, wheat flour meal, fast foods and fruits were situated at the young female side. Aged males liked soup and pot stew. Young males liked meats and eggs whereas fish and shellfish and kimch were located at the aged people side. Aged females liked sea weeds and most people disliked vegetables but females liked some vegetables irrespective of age. Processed foods, salted foods, and alcohol were generally disliked foods by subjects but males liked those foods. Soybean curd was liked more males than females, and teas, except coffee, was liked by males. (Korean J Community Nutrition 14(4) : 392${\sim}$405, 2009)

• Journal of Navigation and Port Research
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• v.33 no.10
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• pp.709-713
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• 2009

Water pollution of coast has a significant impact on the fish farm and fisheries. For solving the water pollution problems the fish farms are moving to the open sea. The fish farms in open sea have to operate by the automatic feeding system and remote monitoring system for safety and management. This paper describes an automatic feeding system for fish farms in open sea. Water temperature and fish weight will change depending on the amount of feed. And the fish farm temperature is changed extremely in open sea than on land side. This paper described that the feed amount is calculated automatically according to temperature, fish weight, and the automatic feed system. And the performance of automatic feed system is verified with test model for operation test.

• Journal of Navigation and Port Research
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• v.34 no.10
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• pp.793-797
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• 2010

The depleting fishes resource and water pollution in coast has a decisive effect on the fish farm and fisheries. For solving these problems the fish farms are moving to the offshore. The fish farms in offshore have to design the strong mechanism as compared with cost's fish farm, and operate by the remote feeding system and monitoring system for safety and management.. This paper describes a remote feeding system for fish farms in offshore. The amount of feed is depending on temperature and fish weight. The fish farm temperature is changed extremely in offshore than on land side. This paper described that the feed amount is calculated automatically according to temperature and fish weight, and the remote feed system. The performance of remote feed system is tested with model.