• Science of Emotion and Sensibility
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• v.25 no.4
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• pp.107-118
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• 2022

Human can rapidly detect and deal with dangerous elements in their environment, and they generally manifest as attentional bias toward threat. Past studies have reported that this attentional bias is affected by anxiety level. Other studies, however, have argued that children and adolescents show attentional bias to threatening stimuli, regardless of their anxiety levels. Few studies directly have compared the two age groups in terms of attentional bias to threat, and furthermore, most previous studies have focused on attentional capture and the early stages of attention, without investigating further attentional holding by the stimuli. In this study, we investigated both attentional bias patterns (attentional capture and holding) with respect to negative emotional stimulus in neurotypical adults and adolescents. The effects of anxiety level on attentional bias were also examined. The results obtained for adult participants showed that abrupt onset of a distractor delayed attentional capture to the target, regardless of distractor type (angry or neutral faces), while it had no effect on attention holding. In adolescents, on the other hand, only the angry face distractor resulted in longer reaction time for detecting a target. Regarding anxiety, state anxiety revealed a significant positive correlation with attentional capture to a face distractor in adult participants but not in adolescents. Overall, this is the first study to investigate developmental tendencies of attentional bias to negative facial emotion in both adults and adolescents, providing novel evidence on attentional bias to threats at different ages. Our results can be applied to understanding the attentional mechanisms in people with emotion-related developmental disorders, as well as typical development.

• Journal of information and communication convergence engineering
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• v.14 no.1
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• pp.45-50
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• 2016

Gait-based classification has gained much interest as a possible authentication method because it incorporate an intrinsic personal signature that is difficult to mimic. The study investigates machine learning techniques to mitigate the natural variations in gait among different subjects. We incorporated several machine learning algorithms into this study using the data mining package called Waikato Environment for Knowledge Analysis (WEKA). WEKA's convenient interface enabled us to apply various sets of machine learning algorithms to understand whether each algorithm can capture certain distinctive gait features. First, we defined 24 gait features by analyzing three-axis acceleration data, and then selectively used them for distinguishing subjects 10 years of age or younger from those aged 20 to 40. We also applied a machine learning voting scheme to improve the accuracy of the classification. The classification accuracy of the proposed system was about 81% on average.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.686-695
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• 2002

Samples of Corbicula ( Corbicula) japonica Prime of Namdae Stream in Gangnung were collected from November 2000 to October 2001. Age of C. (C.) japonica was determined from the rings on the shell, The shell length of the samples ranged from 8 mm to 38 mm. The ring on the shell was formed once a year in March. Von Bertalanffy's growth parameters were estimated using a nonlinear regression method, asyinptotie shell length ($L_{\omega}$) was 48,98 mm, K was 0.20421year, theoretical age at 0 shell length $(t_0)$ was 0.3169 year, and asymptotic total weight ($W_{\omega}$) was 41.37 g. The formula of allomeky between shell length (L, mm) and total weight (W, g) of the brackish water clam was W=3.42$\times$10^{-4}L^{3}. The annual survival rate was estimated at 0.3799, instantaneous coefficient of natural mortality was 0.5007/year, and instantaneous coefficient of fishing mortality was 0.46721year. The age at first capture was estimated at 2.1593 year using shell length compositions of the brackish water clam, The current yield-per-recruit at 0.4672/year of fishing mortality was 0.6595 g. F_0.1 was estimated at 0.1865/year, Acceptable biological catch was estimated at 14.4 metric ton.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.4
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• pp.344-348
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• 2006

The ecological characteristics and stock biomass of the Shiba shrimp, Metapenaeus joyneri, in Korean waters were determined, using fishery data from the Ministry of Maritime Affairs and Fisheries (MOMAF) and available length frequency data. The instantaneous coefficient of total mortality (Z) of M. joyneri was estimated to be 4.191year, and the annual survival rate (S) was 0.015. The estimated instantaneous coefficient of fishing mortality (F) for recent years was calculated to be 1.94/year. The age at first capture of M. joyneri was 0.71 years. Based on these parameters, the annual biomass of the M. joyneri stock was estimated using a biomass-based cohort analysis and data on the annual catch in weight at age for 1993-2004 in Korean waters. During the study period, the biomass of the shrimp peaked in 1994 at about 9,082 metric tons. Subsequently, it decreased to 500 metric tons in 1998.

• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.315-324
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• 2012

The purpose of current study was to investigate the effects of the heights on the lower extremities, torso and neck segments for energy dissipation during single-leg drop landing from different heights. Twenty eight young healthy male subjects(age: $23.21{\pm}1.66yr$, height: $176.03{\pm}4.22cm$, weight: $68.93{\pm}5.36kg$) were participated in this study. The subjects performed the single-leg drop landing from the various height(30, 45 & 60 cm). Force plates and motion-capture system were used to capture ground reaction force and kinematics data, respectively. The results were as follows. First, the ROM at the ankle, knee, hip and trunk was increased with the increased heights but the ROM at the neck was increased in the 60cm. Second, the angular velocity, moment and eccentric work at the ankle, knee, hip, trunk, and neck was increased with the increased heights. Third, the contribution to total work at the knee joint was not significantly different, while the ankle joint rate was decreased and hip and neck rate was increased in the 60cm, and trunk rate was increased with the increased heights. Lastly, the increase in landing height was able to augment the level of energy dissipation not only at the lower extremities but also at the trunk and neck. The findings showed that drop landing affect trunk and neck with lower extremity joints. Therefore, we need to consider that trunk and neck strengthening including stability should be added to reduce sports injury during prevention training.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.3
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• pp.448-453
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• 2015

This study was performed to estimate biomass and to provide management plan through population ecological characteristics, including survival rate, instantaneous coefficient of natural and fishing mortalities, and age at first capture of Flathead grey mullet, Mugil cephalus, in the coastal waters of Yeosu. Survival rate (S) of the flathead grey mullet was 3.671. The instantaneous coefficients of natural mortality (M) and fishing mortality (F) was estimated to be 0.325/year, 0.962/year for flathead grey mullet. Also fist capure age of flathead grey mullet was 3.61year. The current biomass of the flathead grey mullet in the study area was estimated to be 19.6 M/T and $F_{0.1}$ and $F_{40%}$ were estimated 0.340/year, 0.225/year. For the stock assessment result, flathead grey mullet was not overfished but overfishing.

• The Korean Journal of Malacology
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• v.23 no.1
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• pp.31-38
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• 2007

Population ecological parameters and stock biomass of the purplish washington clam, Saxidomus purpuratus (Sowerby), in the southern coastal areas of Korea were determined based on the fishery data from the Divers Fisheries Cooperative and other available biological data. Instantaneous coefficient of total mortality (Z) of purplish Washington clam was estimated to be 0.7479/year. The estimated instantaneous coefficient of natural mortality (M) was 0.2012/year. From the values of Z and M, the instantaneous coefficient of fishing mortality coefficient (F) for the recent years was calculated to be 0.4578/year. The age of purplish Washington clam at its first capture ($t_c$) was 2.7506 year. Yield-per-recruit and spawning biomass-per-recruit were estimated under harvest strategies that bases on $F_{max}$, $F_{0.1}$, $F_{35%}$ and $F_{40%}$ were shown as 81.60 g, 61.68 g, 115.07 g and 131.51 g, respectively. The acceptable biological catch (ABC) was estimated to be about 1,404 metric tons.

• The Korean Journal of Malacology
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• v.27 no.2
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• pp.107-114
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• 2011

The manila clam (Ruditapes philippinarum) is mainly distributed in the coastal area which consist of mud, sand and gravel, but they rarely live on the upper and down reaches of river. For a long time the manila clam has been inhabited in Taehwa river which has been exploited as a traditional earning resources and has become as a major object by neighborhood fishermen. This study was undertaken to evaluate stock assessment and to build management implications with the ecological parameters in Taehwa river from June 2009 to June 2010. The maximum age of manila clam was determined to 6 years old from observing ring radius of shell, the length and weight relationship was TW = $0.0002SL^{3.063}$ ($R^2$ = 0.925). K and $L_{\infty}$ were respectively estimated 46.64 mm and 0.341/year by von Bertalanffy growth. The instantaneous total mortality was estimated to be 1.171/year and the age at first capture was 1.37 years by the Pauly's method using shell length composition. The current total biomass of manila clam was calculated 1,483 mt over study area $1.46\;km^2$ by swept area method. ABC (Acceptable Biological Catch) estimates of manila clam showed 512 mt with using $F_{0.1}$. It's desirable to determine the optimum harvesting time as after main spawning season, as well as it's required to manage fisheries resources considering capture age and biomass through adjusting a first age at capture.

• The Korean Journal of Malacology
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• v.28 no.2
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• pp.109-116
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• 2012

In order to understand the effect of introduction of oyster rack culture on natural short-necked clam, Ruditapes philippinarum, stock, we investigated the status of natural clam stock prior to introduction of oyster rack culture at Yeongheung Coast of Wando Island. The growth equation of the clam was estimated as: $L_t=61.46{\cdot}(1-e^{-0.172(t+0.155)})$ from ring radius composition of shell. Instantaneous coefficient of total mortality and natural mortality were calculated as: 2.4087/year and 0.478/year, respectively. The age at first capture was estimated to be 2.55 year. The total biomass was estimated to 3.23 ton in the bed (0.8 ha). Applied by these parameters, the annual recruit biomass and the current yield per recruit (Y/R) was corresponded to $114.7individuals/m^2$ and $92.0g/m^2$, respectively. Maximum sustainable yield (MSY) was estimated 0.77 ton/year which was close to annual catches, 0.74 ton/year, in the area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.4
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• pp.282-290
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• 1992

Based on surplus production models using fishery data for the last 20 years, a stock assessment was conducted for the small yellow croaker in Korean waters. The maximum sustainable yields (MSY) from the Schaefer and Fox models were estimated to be 37,000 metric tons (mt) and 33,450 mt. Zhang's model using time-series biomass with instantaneous coefficients of fishing mortality (F) and using time-series biomass and catch yielded MSY estimates of 45,328 mt and 40,160 mt, respectively. A yield-per-recruit analysis showed that the current yield per recruit of about 20g with F= 1.11 $yr^{-l}$, where the age at first capture $(t_c)$ is 0.604, was much lower than the maximum possible yield per recruit of 43g. Fixing $t_c$ at the current level and reducing fishing intensity (F) from 1.11 $yr^{-l}$ to 0.4 $yr^{-l}$ yielded only a small increase in predicted yield per recruit, from 20 to 25g. However, estimated yield per recruit increased to 43g by increasing $(t_c)$ from the current age (0.604) to age three with F fixed at the current level. This age at first capture corresponded to the optimal length which was obtained from the $F_{0.1}$ method. According to the analysis of stock recovery strategies employing the Zhang model, the optimum equilibrium biomass $(B^*_{MSY})$ which produces the maximum yield could be achieved after approximately five years at the lower fishing intensity (F=0.5).