• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.57 no.1
• /
• pp.69-78
• /
• 2024

We have proposed a method for estimating the size-dependent mortality (M) of short-lived semelparous cephalopod species. To estimate the size-dependent mortality of a winter cohort of the common squid Todarodes pacificus, a commercially important cephalopod species in the North Pacific, we used the data and results of previous studies. On the basis of the bigger-is-better the steady-state hypothesis, we derived a theoretical mortality curve by assuming M as an inverse function of mantle length (ML). The derived constant for size-specific instantaneous mortality (q), assuming an embryonic survival rate of 86.6%, was 0.413 day^-1 mm in ML. Estimates of life-stage-specific M ranged from 0.0280 to 0.435 day^-1 for paralarvae, 0.00278 to 0.0269 day^-1 for juveniles, 0.00197 to 0.00275 day^-1 for pre-spawning adults, and 0.0913 to 0.0920 day^-1 for post-spawning adults. Sensitivity analyses showed that the derived size-dependent M did not significantly change with varying embryonic survival rates, from 48%, the lowest reported value, to 100%. Additionally, comparison of the length frequencies derived from our simulations with those derived from catch data did not show a significant difference, suggesting that our approach and procedures are reliable for stock assessment and management of the common squid.

• Hip & pelvis
• /
• v.36 no.1
• /
• pp.26-36
• /
• 2024

Total hip arthroplasty (THA) is a frequently performed procedure; the objective is restoration of native hip biomechanics and achieving functional range of motion (ROM) through precise positioning of the prosthetic components. Advanced three-dimensional (3D) imaging and computed tomography (CT)-based navigation are valuable tools in both the preoperative planning and intraoperative execution. The aim of this study is to provide a thorough overview on the applications of CT scans in both the preoperative and intraoperative settings of primary THA. Preoperative planning using CT-based 3D imaging enables greater accuracy in prediction of implant sizes, leading to enhancement of surgical workflow with optimization of implant inventory. Surgeons can perform a more thorough assessment of posterior and anterior acetabular wall coverage, acetabular osteophytes, anatomical landmarks, and thus achieve more functional implant positioning. Intraoperative CT-based navigation can facilitate precise execution of the preoperative plan, to attain optimal positioning of the prosthetic components to avoid impingement. Medial reaming can be minimized preserving native bone stock, which can enable restoration of femoral, acetabular, and combined offsets. In addition, it is associated with greater accuracy in leg length adjustment, a critical factor in patients' postoperative satisfaction. Despite the higher costs and radiation exposure, which currently limits its widespread adoption, it offers many benefits, and the increasing interest in robotic surgery has facilitated its integration into routine practice. Conducting additional research on ultra-low-dose CT scans and examining the potential for translation of 3D imaging into improved clinical outcomes will be necessary to warrant its expanded application.

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

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.22 no.5
• /
• pp.1-12
• /
• 2019

It is important to measure the height of trees as an essential element for assessing the forest health in urban areas. Therefore, an automated method that can measure the height of individual tree as a three-dimensional forest information is needed in an extensive and dense forest. Since airborne LiDAR dataset is easy to analyze the tree height(z-coordinate) of forests, studies on individual tree height measurement could be performed as an assessment forest health. Especially in urban forests, that adversely affected by habitat fragmentation and isolation. So this study was analyzed to measure the height of individual trees for assessing the urban forests health, Furthermore to identify environmental factors that affect forest growth. The survey was conducted in the Mt. Bongseo located in Seobuk-gu. Cheonan-si(Middle Chungcheong Province). We segment the individual trees on coniferous by automatic method using the airborne LiDAR dataset of the two periods (year of 2016 and 2017) and to find out individual tree growth. Segmentation of individual trees was performed by using the watershed algorithm and the local maximum, and the tree growth was determined by the difference of the tree height according to the two periods. After we clarify the relationship between the environmental factors affecting the tree growth. The tree growth of Mt. Bongseo was about 20cm for a year, and it was analyzed to be lower than 23.9cm/year of the growth of the dominant species, Pinus rigida. This may have an adverse effect on the growth of isolated urban forests. It also determined different trees growth according to age, diameter and density class in the stock map, effective soil depth and drainage grade in the soil map. There was a statistically significant positive correlation between the distance to the road and the solar radiation as an environmental factor affecting the tree growth. Since there is less correlation, it is necessary to determine other influencing factors affecting tree growth in urban forests besides anthropogenic influences. This study is the first data for the analysis of segmentation and the growth of the individual tree, and it can be used as a scientific data of the urban forest health assessment and management.

• Korean Journal of Ecology and Environment
• /
• v.43 no.1
• /
• pp.82-90
• /
• 2010

The ecological characteristics of the Korean Aucha perch, Coreoperca herzi, were determined in order to estimate stock of the mid-upper system of the Seomjin River. The age was determined by counting the otolith annuli. The oldest fish observed in this study was 5 years old. Relationships between body length (BL) and body weight (BW) were $BW=0.0195BL^{3.08}$ ($R^2=0.966$) (p<0.01). Relationships between the otolith radius (R) and body length (BL) were BL=3.882R+1.66 ($R^2=0.944$). The von Bertalanffy growth parameters estimated from a non-linear regression method were $L_{\infty}=19.68\;cm$, $W_{\infty}=188.64\;g$, $K=0.17\;year^{-1}$ and $t_0=-1.46$ year. Therefore, growth in length of the fish was expressed by the von Bertalanffy's growth equation as $L_t=19.68$ ($1-e^{-0.17(t+1.46)}$) ($R^2=0.997$). The annual survival rate (S) was estimated to be $0.666\;year^{-1}$. The instantaneous coefficient of natural mortality (M) of estimated from the Zhang and Megrey method was $0.346\;year^{-1}$, and instantaneous coefficient of fishing mortality (F) was calculated $0.061\;year^{-1}$. From the estimates of survival rate (S), the instantaneous coefficient of total mortality(Z) was estimated to be $0.407\;year^{-1}$.

• Journal of the Korea Society of Computer and Information
• /
• v.18 no.9
• /
• pp.139-152
• /
• 2013

Although a series of studies shows the fact that a company's reputation could affect its sales rate and stock price, due to the increased use of SNS, the research related to the online measurement method for the corporate reputation has been relatively insufficient. This study explores a design for a method to quantify the corporate reputation value by reconstructing the discussions in literature review. Concretely, this study divides the corporate reputation value into the corporate identity information and the corporate awareness information, which includes the following five sub-categories: (1) the quality of product and service; (2) the employment environment; (3) the corporate vision; (4) the social responsibility; and (5) the business achievement. Additionally, for the corporate identity assessment, this study considers the following six factors: (1) Agreeableness (Goodness), (2)Capability (Ability), (3)Enterprise (Rise), (4)Chic (Class), (5) Ruthlessness (Authority), and (6)Informality. Based on these categories and factors, this study develops a technique quantifying the corporate reputation value by selecting 'word items' for the reputation search, and after conducting a frequency analysis in a survey. Also, to verify the result, this study exemplifies the reputation of three SI companies in Korea which could be utilized by using the commercialized reputation service. This study firstly attempts the corporate reputation measurement by classifying the identity and the awareness (corporate image and communication) upon a company in detail and enables its real applicabilities by proposing a formula to measure the reputation scores which can be utilized by verified word items from a frequency analysis.

• The Korean Journal of Quaternary Research
• /
• v.18 no.2 s.23
• /
• pp.107-107
• /
• 2004

In this paper we have introduced some results of study on stand growth pattern and stand structure of larch forest which are located in selected forest sites of Khangai and Gobi-Altai mountain ranges of Mongolia. Our investigations showed that growth intensity and stand structure in western Mongolia are very specific from the other forest vegetation zones of Mongolia. Studies on the stand structure and growth trend indicate that tree types of stand structure and different types of growth of Larix sibrica are very common in Western Mongolia. These peculiarities of stand structure and growth of larch stands in Western Monolia could be used for inventory work and an improvement of the forest management in Western Mongolian region. The larch tree is the dominant tree species in Western Mogolia. Forest cover of the region is about 15%, which is two times higher than the country's average. In this region forest area is divided into 4 forest sub-regions: the Central Khangai, Western Khangai, North Eastern Khangai and South Easterun Khangai sub-regions including taiga, pseudo taiga, sub taiga, sub-alpine and forest steppe belts. Silviculture practices and forest research management request to study forest growth trends in local and general conditions, which means to indicate a change of taxonomic characteristics of stand from time to time including diameter, height, basal area, growth stock etc. The forest management practice mostly uses tables of forest growth and yield based on the results of long term research on forest growth. Forest yield tables and other relevant forest standards of Russia are used for the forest inventory and forest management. They are not able to determine forest structure and growth peculiatities of Mongolian forests. Studies on forest resource assessment in Mongolia indicate that after logging operations and forest fires the natural regeneration of desired species such as pine and larch often does not succeed. This situation forces to take a different approach of forest management and silviculture practice depending on the stand structure and growth rate of the forest stands. According to our investigation in last years, forest growth pattern of larch forest depends mostly on stand structure, stand age and growth condition including forest soil, climate and location in different slopes. Due to improve environmental function of forest ecosystem in the region, it is needed to conduct very comprehensive study of high mountain forest ecosystem in selected sub-regions.

• Korean Journal of Environment and Ecology
• /
• v.29 no.5
• /
• pp.681-692
• /
• 2015

It is well documented that physiological and nutritional condition of wintering birds is strongly related to migration success to breeding sites, and also breeding success. However, how abiotic factors during winter affect the migration and breeding successes still remains unclear. Thus, this study developed a dynamic-state-dependent model for wintering life-history to identify the potential impact on the life-history, success to breeding site and breeding success of wintering birds, which are related to temperature fluctuation, interspecific competition and human disturbance at the wintering sites. To find the best-fit-model, we referred to the existing research data on wintering ecology of Red-crowned cranes (Grus japonensis) in Cheolwon, Korea, which is well documented as a long-term wintering study. Our model predicted that the higher temperature fluctuation and a higher rate of human disturbance are negatively related to migration success to breeding sites and their fitness, ultimately breeding success via changing of proportion in resource allocation (for e. g., lower energy compensation or higher level of stress accumulation). Particularly, the rate of body mass compensation after arrival at wintering sites may be accelerated when there are less temperature fluctuations and a lower rate of human disturbance. In addition, the rate of interspecific competition sharing the wintering foraging sites is negatively related to the rate of body mass compensation. Consequently, we discussed the conservation strategies of wintering birds based on the outcomes of the model.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.56 no.4
• /
• pp.347-360
• /
• 2020

In this study, the Bayesian state-space model was used for the stock assessment of the Blackfin flounder. In addition, effective measures for the resource management were presentedwith the analysis on the effectiveness of fisheries management plans. According to the result of the analysis using the Bayesian state-space model, the main biometric value of Blackfin flounder was analyzed as 1,985 tons for maximum sustainable yield (MSY), 23,930 tons for carrying capacity (K), 0.000007765 for catchability coefficient (q) and 0.31 for intrinsic growth (r). Also the evaluation on the biological effect of TAC was done. The result showed that the Blackfin flounder biomass will be kept at 14,637 tons 20 years later given the present TAC volume of 1,761 tons. If the Blackfin flounder TAC volume is set to 1,600 tons, the amount of biomass will increase to 16,252 tons in the future. Lastly, the biological effectiveness of the policy to reduce fishing effort was assessed. The result showed that the Blackfin flounder biomass will be maintained at 13,776 tons if the current fishing efforts (currently hp) level is set and maintained. If the fishing effort is reduced by 20%, it will increase to 17,091 tons in the future. The analysis on the economic effect of TAC showed that NPV will be the lowest at 1,486,410 won in 2038, 20 years after the establishment of 2,500 tons of TAC volume. If the TAC volume is set at 2,000 tons, NPV was estimated to be the highest at 2,206,522,000 won. In addition, the analysis on the economic effect of the policy to reduce the amount of fishing effort found that NPV will be 2,235,592,000 won in 2038, 20 years after maintaining the current level of fishing effort. If the fishing effort is increased by 10%, NPV will be the highest at 2,257,575 won even thoughthe amount of biomass will be reduced.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2003.10a
• /
• pp.170-170
• /
• 2003

An initial study has been conducted with Korea Institute of Geoscience and Mineral resources and National Institute of Environment Research to evaluate the distribution of radon levels and their risk levels of groundwater in Korea. Probability distribution of 616 samples was log-normal one with 1,867pCi/L as arithmetic value, 920pCi/L as median and 40,010pCi/L as maximum during iou. years(1999-2002). In addition, 10% of total samples are in excess of 4,000pCi/L, 20% in excess of 2,700pCi/L, and 30% in excess of 1,700pCi/L, and 15 samples exceeds 10,000pCi/L. Total samples are grouped into 10 areas and 5 rocks unit, and difference of concentrations among areas and rocks are statistically significant(respectively, p<0.0001). The highest area is Daejeon located in ogcheon metamorphic rocks and granitic rocks, and most of all sites with high concentration sites are located in granitic rocks. The lowest area is Jeju located in volcanic rocks. We have estimated excess cancer risks of radon based on these data. To estimate risks, first of all, use patterns of groundwater are categorized with 6 groups: for drinking, household, farming, washing cars, raising stock, and others. We considered risk only for drinking water and household water because radon is rapidly dispersed before it of other use reach human respiratory organs. We select 565 samples for risk analysis, and applied unit risk which is 6.6210-7 per pCi/L to be recommended by NAS committee. Unit risk was derived from considering radon ingestion and radon inhalation from water use. When estimating risk, we analyzed PDF of concentration and represented risk as 50 and 95 percentile values to consider uncertainty with Monte-Carlo simulation. It results in 10-4 level of their excess cancer risk and in 10-2 level in some areas with high concentration of radon. It must be monitor periodically and take adequate actions in these risky sites. We recommend that it needs to take more survey and finally set guideline for radon regulation in groundwater.