• Management & Information Systems Review
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• v.37 no.3
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• pp.83-113
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• 2018

The purpose of this study to empirically examine a smart work investment and job performance by change resistance. Firstly, There investigates mediating role of the communication between the smart work investment and the job performance. Secondly, It will identify the job productivity differences through a level of organizational change resistance that reduced smart work investment. The smart work is to provide the flexibility of time and location and is a working method to improve a work productivity of organization members. The introduction of smart work means the adoption of new organizational culture, institution and technology and requires a novel change of a custom and pattern on existing organization culture and institution because of transformation form of communication and collaboration. The method of this study adopts a structural equation model to test a mediating effect of communication and a moderating effect of change resistance level. This model confirms whether smart work investments provide a positive impact on communication and organizational productivity. In addition, I will classify a change resistance level of smart work by cluster analysis and then check a critical path difference of job productivity between each group. As a result, The organizational IT, institution and culture on the smart work investment appeared to important influencers in communication and also had a direct influence of individual performance. Also, The three independent variables of smart work investment have an indirect influence of individual and organizational performance through communication mediating variables. However, the organizational IT and institution as independent variables do not provide direct influence of organization performance. Nevertheless, two independent variables of organizational IT and institution have an indirect influence the organization performance through communication mediating variables. As a result of confirming a productivity of three groups on organization resistance, there was a difference the individual and organizational performance among groups. The low-level group of organizational resistance showed high coefficient value of performance compared to other groups. The group analysis implications, The smart work investment appeared significantly to revise the institution first, build culture secondly and advanced technology lastly. The theoretical implication from this study contributes an extension of social science theory through socio-technical systems, institution, culture, change resistance and job performance based on smart work. The practical implications explain the smart work success in step-by-step investment rather than radical investment as level management of change resistance. In future research, the smart work performance between private and public firms will analyze a difference of the organizational culture, institution, technology and performance.

• Journal of Aquaculture
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• v.6 no.4
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• pp.323-338
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• 1993

The primary objective of this study was to examine the toxic effects of PCP on activated sludge and to analyze its metabolic responses while treating wastewater containing pentachlorophenol (PCP) in a sequencing batch reactor (SBR) system operating under different control strategies. This study was conducted in two phases 1 and 2 (8-hr and 12-hr cycles). Each phase was operated with two control strategies I and II. Strategy I (reactor 1) involved rapid addition (5 minutes to complete) of substrate to the reactor with continuous mixing but no aeration for 2 hours. Strategy II (reactor 2) involved adding the feed continuously during the first 2 hours of the cycle when the system was mixed but not aerated. During both phases each reactor was operated at a sludge age of 15 days. The synthetic wastewater was used as a feed. The COD of the feed solution was about 380 mg/L. After the reference response for both reactors was established, the steady state response of each system was established for PCP feed concentrations of 0.1 mg/L, 1.0 mg/L, and 5.0 mg/L in SBR systems operating on both 8-hr and 12-hr cycles. Soluble COD removal was not inhibited at any feed PCP concentrations used. At 5.0 mg/L feed PCP concentration and in SBR systems operating on phase 2, the concentrations or ML VSS were decreased; selective pressure on the mixed biomass might be increased, narrowing the range of possible ecological responses; the settleability of activated sludge was poor; the SOURs were increased, showing that the systems were shocked. Nitrification was made to some extent at all concentrations of feed PCP in SBR systems operating on phase 2 whereas in SBR systems operating on phase 1 little nitrification was observed. Then, nitrification will be delayed as much as soluble COD removal is retarded due to PCP inhibition effects. Enhanced biological phosphorus removal occurring in the system operating with control strategy I during phase 1 of this work and in the presence of low concentrations of PCP was unreliable and might cease at anytime, whereas enhanced biological phosphorus removal occurring in the system operating with either control strategy I or II during phase 2 of this work and in the presence of feed PCP concentrations up to 1.0 mg/L was reliable. When, however, such processes were exposed to 5.0 mg/L PCP dose, enhanced phosphorus removal ceased and never returned.

• Journal of Aquaculture
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• v.6 no.2
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• pp.107-123
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• 1993

To define the effects of various levels $(0\~1.5\%)$ of dietary n-3HUFA on the physiological changes in the Korean rockfish, variations in blood variables and hepatocytes were studied. Biochemical serum analyses, lactate dehydrogenase (LDH) activity of the liver cytosol and ATPase activity of the liver microsomal membrane were also studied. The haematological values (red blood cell, hemoglobin, hematocrit, MCHC, MCV and MCH) were not significantly different in the experimental groups $(P\geq0.05)$. The total protein and glucose levels in the serum were affected by dietary n-3HUFA levels. These levels in groups fed n-3HUFA insufficient diets were significantly lower than those of n-3HUFA sufficient groups (P<0.05). Serum levels of total cholesterol, free cholesterol, glutamic pyruvic transaminase (GPT) and glutamic oxaloacetatic transaminase (GOT) showed significantly higher values in the fish fed n-3HUFA deficient diets (P<0.05). The LDH in the serum was dropped with increasing dietary n-3HUFA levels, but the LDH activity of the liver cytosol was elevated. Histologically, the hepatic cell in the fish fed n-3HUFA free diet was abnormal and showed a necrotic condition. $Ca^{2+}-ATPase$ activities of the liver microsomal membrane were significantly lower in the fish fed n-3HUFA deficient diets than in those fed n-3HUFA sufficient diets (p<0.005). These results suggested that the liver cell membrane was affected by dietary fatty acid compositions and cell membrane of the fish fed n-3HUFA insufficient diets showed abnormalities.

• Journal of Aquaculture
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• v.19 no.3
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• pp.173-177
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• 2006

This study was conducted to evaluate extruded pellets (EP) for growth of adult flounder by comparing with raw fish-based moist pellet (MP). Two replicate groups of 150 fish per each tank (initial mean weight 329 g) were fed one of seven EP (EP1, EP2, EP3, EP4, EP5, EP6 and EP7) and a MP for 8 months. Survival of fish fed the MP was not significantly different from that of fish fed the EP1, EP5 and EP7, but significantly higher than that of fish fed the EP2, EP3, EP4 and EP6 (P<0.05). Weight gain of fish fed the MP was significantly lower than that of fish fed the EPI (P<0.05), but not significantly different from that of fish fed EP2, EP3, EP4, EP5, EP6 and EP7. Feed efficiency of fish fed the MP was significantly lower than EP1, EP3, EP4, EP5 and EP6 (P<0.05), but not significantly different from that of fish fed EP2 and EP7 Feed supply (kg/tank) of fish fed the MP was significantly higher than that of fish fed all EP (P<0.05). Condition factor of fish fed the MP was not significantly different from that of fish fed all EP. The contents of moisture, crude protein and lipid in dorsal muscle and whole body was not significantly different among the groups. It is concluded that the dietary formulation used in the EP1, EP3, TP4, EP5 and EP6 can be applied in the practical extruded pellet feeds for adult flounder (329-680g).

• Journal of Aquaculture
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• v.19 no.3
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• pp.210-215
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• 2006

An experiment was conducted to investigate the effects of four water temperatures (10, 15, 20, and $25^{\circ}C$) in combination with three photoperiods (24L:0D, 12L: 12D, and OL:24D) on the oxygen consumption rate of juvenile dark-banded rockfish, Sebastes inermis (mean body weight $20.5{\pm}0.7g$). The oxygen consumption rates of S. inermis were measured in triplicate for 24 hours using a continuous flow-through respirometer. Different combinations of water temperatures and photoperiods resulted in significant differences in the mean oxygen consumption rate of S. inermis (P<0.001). The oxygen consumption increased with increasing water temperatures for all photoperiod treatments (P<0.01). Mean oxygen consumption rates at 10, 15,20 and $25^{\circ}C$ ranged $178.3\sim283.5,\;386.7\sim530.7,\;529.2\sim754.3$ and $590.0\sim785.5mg\;O_2kg^{-1}h^{-1}$, respectively. $Q_{10}$ values ranged $3.17\sim5.51$ between 10 and $15^{\circ}C,\;1.87\sim2.10$ between 15 and $20^{\circ}C$ and $1.08\siml.24$ between 20 and $25^{\circ}C$, respectively. Fish held in continuous darkness (OL:24D) used consistently less okygen than fish exposed to continuous light (P<0.05). The mean oxygen consumption offish in a 12L:12D photoperiod was higher than that offish in 24L:0D and 0L:24D photoperiods under all temperature treatments except $10^{\circ}C$. The oxygen consumption of fish exposed to the 12L:12D photoperiod was significantly higher during the light phase than during the dark phase under all temperature treatments except $10^{\circ}C\;(P<0.05)$. This study provides empirical data for estimating oxygen consumption of S. inermis under given condition. This result has application for culture management and bioenergetic model for growth of this species.

• Journal of Aquaculture
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• v.11 no.4
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• pp.547-556
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• 1998

This study was performed to obtain the basic data on the serum constituents of several marine fish spesies commonly cultured in Korea. Blood samples taken from six species of fish were analyzed for various components of serum, total protein (TP), albumin (ALB), triglyceride (TRIG), cholesterol (CHOL), glucose (GLC), lipase (LIPA), amylase (AMYL), aspartate transaminoferase (AST), sodium (Na), potassium (K), chloride (CI) and phosphorus (PHOS). The fish used were coho salmon (Oncorhynchus kisutch), rock fish (Sebastes schlegeli), sea bass (Lateolabrax japonicus), olive flounder (Paralichthys olivaceus), rock fish (Sebastes schlegeli), sea bass (Lateolabrax japonicus), olive flounder (Paralichthys olivaceus), parrot fish (Oplegnathus fasciatus) and jack mackerel (Trachurus jaonicus) reared at the Chungmu Experimental Fish Culture Station of KORDI when the water tempetature was ca. 16.5$^{\circ}C$. There were significant differences in TRIG, CHOL, LIPA and AMYZ among the species analyzed. TRIG concentratin were ranged 178~180mg/dl in jack mackeerel and rock fish, 126~159 mg/dl in olive flounder and sea bass, and 102~114 mg/dl in coho salmon and parrot fish, respectively. Jack mackerel showed the highest levels in CHOL (255mg/dl) and GLC(138mg/dl) among species. LIPA levels were recorded 256 U/dl in coho salmon, 41~42 U/dl in parrot fish and rock fisk, and 5~11 U/dl jack mackerel and sea bass, respectively. AMYL activity of coho salmon was measured as 2, 665 U/dl, and that of jack mackerel was 1,210 U/dl while sea bass showed 60 U/dl and parrot fish, olive flounder and rock fish had at most 5 U/dl. On the other hand, there was no significant difference in the concentration of Na and CI. Na and K were proved that they were negatively correlated in all the species. Generally, among blood components, PHOS and CHOL levels were different depending on environmental temperature of each fish species, especially in olive flounder. Rock fish and parrot fish showed high blood concentration of those components during low temperature period while olive flounder and jack mackerel reached high level during their optimal environmental temperature period. The electrolyte concentration and LIPA activity were high during low water temperature period, in general, but TP and ALB concentrations were high during optimal temperature period. The concentrations of TRIG, CHOL and GLC, those which were used as energy sourses, were different among species by season.

• Journal of Aquaculture
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• v.14 no.3
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• pp.181-195
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• 2001

To stabilize the lantern cage culture system of Patinopecten yessoensis(Jay) in the eastern coast of Korean peninsula, optimum conditions such as time of transplantation, rearing density and depth, and time of harvest were identified. During the period from January 1991 to December 1998, the water temperature ranged from 4.7 to 21.4$^{\circ}C$ at 15-30 m depth and 4.9 to 25.7$^{\circ}C$ at the surface; these thermal ranges were within the optimal ranges (5-23$^{\circ}C$) prevailing at 15-30 m depth at surface water. Annual thermal changes indicated that the prevailing temperature during the years 1993 and 1996 was near optimum, but higher during the years 1994, 1997 and 1998, when mass mortality and growth retardation occurred. Salinity (32.0- 34.4$\textperthousand$) and dissolved oxygen (4.14 -8.11 $\mu\textrm{g}$/l) at 15 m depth were well within the optimum ranges. The chlorophyll concentrations (0.06 - 2.73$\mu\textrm{g}$/l) indicated that the study area was oligotrophic, although mass mortality did occur, when chlorophyll concentrations were high, especially in summer. Hence water temperatures and chlorophyll concentration are major factors related to survival and growth of the scallop. In terms of the shell height maximum growth occurred during spring (March-May; 8 - l3$^{\circ}C$) and fall (October-December; 11-l7$^{\circ}C$) in the lantern cage culture. Slow growth was recorded during late winter January-february; less than 7$^{\circ}C$) and mid-summer (August- September; more than 18$^{\circ}C$). Daily growth of shell height and total weight were 0.02∼0.24 mm and -0.07∼0.90 g at the rearing density of 12 individuals per net. Optimal .earing density in the lantern cage (ø50${\times}$20 cm) was 10∼15 individuals with the shell height of 5∼6 cm. The fastest growth rates were observed at 15∼20 m depth; however, it is recommended that 20∼30 m would be optimal. The scallops require 22 months to attain the commercial size of 10 cm shell height and 140 g total weigh, and are best harvested and sold during March-April.

• Journal of Aquaculture
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• v.14 no.3
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• pp.197-203
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• 2001

To replace fish meal (FM) in the diet of Nile tilapia, Oreochromis nloticus, different levels of Iysine cell mass (LCM) were added to diet on protein equivalent base. fish averaging 3.0 g fed one of nine diets containing isonitrogenous and isocaloric basis of 35% crude protein and 15.3kJ available energy/g diet: $LCM_0, 100% FM: LCM_{10}, 90% FM+10% LCM, LCM_{20}, 80% FM+20% LCM; LCM_{30}, 70% FM+30% LCM; LCM_{40}, 60% FM+40% LCM; LCM_{30}l, 70% FM+30% LCM+lysine; LCM_{30}ln, 70% FM +30% LCM + lysine +NaOH; LCM_{40}lan, 60% FM+40% LCM+lysine+arginine; LCM_{40}/lan, 60% FM+40% LCM+lysine+arginine+NaOH.$. After 8 weeks of feeding trial, there were no significant differences in weight gain (WG) and specific growth rate (SGR) among fish fed LCM$_{0}$ (control diet), LCM_{10}, LCM_{30}, LCM_{40}, LCM_{30}l, LCM_{30}ln, LCA_{40}la and LCM_{40}lan diets (P>0.05)$, while fishes fed $LCM_{20} diet were significantly higher than those fed LCM_{0}, LCM_{30}, LCM_{40}, LCM_{40}la and LCM_{40$}lan diets (P<0.05). There were no significant differences in feed efficiency (FE) and protein efficiency ratio (PER) among fish fed control diet, $LCM_{10}, LCM_{20}, LCM_{30}ln, LCM_{ 40}la and LCM_{40}$lan diets (P>0.05), while fishes fed control diet were significantly higher than those fed $LCM_{30}, LCM_{40} and LCM_{40}l diets (P<0.05)$. Positive effects were not shown in WG and SGR with supplementation of amino acids (lysine & arginine) and neutralizatio, while FE and PER from fish fed $LCM_{40}la and LCM_{40}lan diets were significantly higher than those fed LCM_{30}, LCM_{40} and LCM_{30}$l diets (P<0.05). Hence, LCM can replace FM up to 40%, and dietary suppl-ementacon and neutralization of amino acids showed positive effects, when FE and PER were considered in juvenile tilapia diet.

• Journal of Aquaculture
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• v.16 no.3
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• pp.135-141
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• 2003

Physiological responses (cortisol, glucose, lactic acid, osmolality and hematology) of olive flounder (Paralichthys olivaceus) to stressors associated with confinement and subsequent transport were investigated. Specimens were subjected to confinement stress for 3 h, prior to transport for 15 h. Two different size cohorts of the fish, large (839.6$\pm$162.7 g) and small (98.2$\pm$14.8 g), were used. Experimental cohorts of the fish were divided into 3 groups for blood sampling: group A, sampled at the beginning of confinement and 3 h before transport (BT, -3 h), after confinement and at the beginning of transport (BT, 0 h), 3 h after transport had begun (AT, 3 h), and after 15 h transport (AT, 15 h); group B, sampled at BT, 0 h, at AT, 3 h, and at AT, 15 h; and, group C, sampled at AT, 3 h, and at AT, 15 h. In the cohort of large fish, plasma cortisol levels of the A group were increased over time, from 4.2 ng/ml (BT,-3 h), to 92.0 ng/ml (BT, 0 h), 118.5 ng/ml (AT, 3 h) and 105.5 ng/ml (AT, 15 h). A similar pattern was evident in the B group, in which cortisol increased from 47.5 ng/ml (BT, 0 h) to 53.5 ng/ml (AT, 15 h); and, for the C group, in which cortisol increased from 43.5 ng/ml (AT, 3 h) to 71.5 ng/ml (AT, 15 h). Glucose levels of the A group also were significantly increased, from 39.5 mg/dl (BT,-3 h), to 121.0 mg/dl (BT, 0 h),298.0 mg/dl (AT, 3 h) and 260.5 mg/dl (AT, 15 h). Lactic acid levels increased markedly during transport, from less than 1 mmol/L (BT, 0 h) to 12.0 mmol/L (AT, 15 h). Plasma osmolality increased from 405.5 mOsm/kg (BT, -3 h, for group A) to values near 500 mOsM/kg subsequent to confinement and transport. In the small-size cohort, plasma cortisol, glucose, lactic acid and osmolality levels showed similar but less pronounced trends than those observed for the large-size cohort. This research provides baseline data on cortisol, glucose, lactic acid, osmolality and hematological responses to confinement and transport, which should be useful to aquaculturists working with olive flounder and to scientists studying other flatfish species.

• Journal of Aquaculture
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• v.16 no.3
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• pp.190-195
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• 2003

Dietary optimum ratio of frozen raw fish and commercial compound meal (CCM) in moist pellet (MP) were investigated to improve the growth rate, and feed and economical efficiency in the flounder, Paralichthys olivaceus. Experimental fish (average body weight, about 48 g) were divided into 6 groups and each group was fed with raw fish (FRF), and MPs (ratio of raw fish and CCM=9:1, 8:2, 7:3, 6:4 and 5:5) for 10 weeks. The 9:1, 8:2, 7:3, 6:4, 5:5 groups showed no significant difference in weight gain as 203.5~217.3%, while the FRF group showed significantly low growth rate as 183.1%(P<0.05). The feed efficiency gradually increased with the increase in the ratio of CCM and was the highest in the 5:5 group as 89.7%. As a result of analysis of body composition after the experiment, moisture was significantly low in the 7:3 group (P<0.05) and crude protein was significantly low in the 9:1 group (P<0.05). The crude lipid increased as the ratio of raw fish increased, and it was the highest in the raw fish group (8.3%) and the lowest in the 5:5 group (4.6%). There were no significant difference in hepatosomatic index (HSI) and condition factor(CF) among the experimental groups. Visceralsomatic index (VSI) increased with the increase in the ratio of raw fish and was significantly high in the raw fish group as 5.49 (P<0.05). For the unit cost of feed, it was found that raw fish was economical when mackerel, a source of raw feed, was 400 won/kg, while the ratio of 5:5 was economical when it was more than 500 won/kg. Results of this study concluded that sole use of raw feed is not desirable in view of growth, environment and economy, and the 5:5 group showed highest effect under the least use of raw feed.