• Journal of Korean Society of Transportation
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• v.22 no.6
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• pp.47-54
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• 2004

Recently, a large reduction in domestic aviation demand had roughly shown in the range between 34% and 75% in east central and western corridor of Korea. The reasons for the drop in air traffic demand were the provisioning of several new highway serveces and the national economic difficulties. Since April 2004, moreover, the Korea Train Express(KTX) was operated between Seoul and Daegu in the first phrase of 293Km in KTX operational distance and 258Km in air route distance. The operation of KTX significantly impacted air traffic volume, particularly on the overlapped air routes with KTX routes. This study analyzed the effects on air traffic demand in accordance with the opening of KTX by applying the Stated Preference (SP) survey method, the survey conducted prior to 8 months of the KTX initiative. Also, the comparison of the decreased demand forecast by SP analysis and actual revealed traffic volume during two months service after inauguration of KTX was conducted. The Seoul-Daegu route was analysed using the 3 variables considered access and egress time, fare rate, operational frequency. The result obtained from the analysis showed that air users would be preferred only 14%. Comparatively, however, the actual revealed air passengers after the opening KTX were remained 28%, The less "decreased demand" was caused by the instability of the KTX's operation in the initial stage. Therefore, small numbers of passenger were preferable to airservices rather than high speed railroad service.

• Journal of Korean Society of Transportation
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• v.31 no.1
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• pp.3-13
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• 2013

This paper reviews the characteristics of dilemma zone by analysing the influence exerted by actual location of intersection traffic signal on behaviour of drivers approaching signalized intersection in urban area. The analysis of approach speed was based upon a 'before and after' comparison, measured at three sites where the locations of traffic signals were changed. The study demonstrated that, when traffic signal changed to yellow, the scales of dilemma zone were narrowed in case of stopping cars by moving up the starting point of the dilemma zone due to lowered spot speed. On the other hand, in case of passing cars, the end points of dilemma zone were moved further out to the rear due to increased spot speed. Therefore, changing traffic signal locations could make an impact to increase intersection safety through reducing the scales of dilemma zone. This study also found that, in cases involving vehicles with similar approach speeds, spot speeds could be differentiated following the change of signal locations due to the fact that there can be greater differences in both braking point and deceleration rate. Thus, when considering the appropriate measuring of dilemma zone, 'spot speed' rather than 'approach speed' appeared to be more appropriate criterion.

• Tunnel and Underground Space
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• v.21 no.5
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• pp.394-405
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• 2011

In this paper, we applied coupled non-isothermal, multiphase fluid flow and geomechanical numerical modeling using TOUGH-FLAC coupled analysis to study the complex thermodynamic and geomechanical performance of underground lined rock caverns (LRC) for compressed air energy storage (CAES). Mechanical stress in concrete linings as well as pressure and temperature within a storage cavern were examined during initial and long-term operation of the storage cavern for CAES. Our geomechanical analysis showed that effective stresses could decrease due to air penetration pressure, and tangential tensile stress could develop in the linings as a result of the air pressure exerted on the inner surface of the lining, which would result in tensile fracturing. According to the simulation in which the tensile tangential stresses resulted in radial cracks, increment of linings' permeability and air leakage though the linings, tensile fracturing occurred at the top and at the side wall of the cavern, and the permeability could increase to $5.0{\times}10^{-13}m^2$ from initially prescribed $10{\times}10^{-20}m^2$. However, this air leakage was minor (about 0.02% of the daily air injection rate) and did not significantly impact the overall storage pressure that was kept constant thanks to sufficiently air tight surrounding rocks, which supports the validity of the concrete-lined underground caverns for CAES.

• Parasites, Hosts and Diseases
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• v.53 no.5
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• pp.535-543
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• 2015

Integrated control strategies are important for sustainable control of schistosomiasis and soil-transmitted helminthiasis, despite their challenges for their effective implementation. With the support of Good Neighbors International in collaboration with National Institute of Medical Research, Mwanza, Tanzania, integrated control applying mass drug administration (MDA), health education using PHAST, and improved safe water supply has been implemented on Kome Island over 5 years for controlling schistosomiasis and soil-transmitted helminths (STHs). Baseline surveys for schistosomiasis and STHs was conducted before implementation of any integrated control strategies, followed by 4 cross-sectional follow-up surveys on randomly selected samples of schoolchildren and adults in 10 primary schools and 8 villages, respectively, on Kome islands. Those follow-up surveys were conducted for impact evaluation after introduction of control strategies interventions in the study area. Five rounds of MDA have been implemented from 2009 along with PHAST and improved water supply with pumped wells as other control strategies for complementing MDA. A remarkable steady decline of schistosomiasis and STHs was observed from 2009 to 2012 with significant trends in their prevalence decline, and thereafter infection rate has remained at a low sustainable control. By the third follow-up survey in 2012, Schistosoma mansoni infection prevalence was reduced by 90.5% and hookworm by 93.3% among schoolchildren while in adults the corresponding reduction was 83.2% and 56.9%, respectively. Integrated control strategies have successfully reduced S. mansoni and STH infection status to a lower level. This study further suggests that monitoring and evaluation is a crucial component of any large-scale STH and schistosomiasis intervention.

• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.358-363
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• 2014

Herbs have active components that promote the growth rate of both animals and human. The KI-180 and KI-188 calcium food formulae contain Acanthopanacis cortex, Bombysis corpus and hoelen, seaweed calcium, chlorella extract, spirulina, colostrum powder, and other natural and functional components. We evaluated the growth-promoting effects of these formulae by analyzing the weight, femur and backbone, alkaline phosphatase, osteocalcin, testosterone, insulin-like growth factor (IGF)-1, and IGF binding protein-3 (IGFBP-3) of growing rats. Growing rats administered with KI-180 and KI-188 calcium showed the increase of body weight, body length, and femur weight and length of growing rats. In addition, administration of KI-180 and KI-188 calcium increased the alkaline phosphatase activity, the levels of osteocalcin and the growth hormones IGF-1 and IGFBP-3 of growing rats. The impact of KI-180 and KI-188 calcium on the physical development of growing rats suggests that the incorporation of these food formulae in the diets of growing children may promote the physical development.

• Journal of fish pathology
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• v.12 no.1
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• pp.32-41
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• 1999

Ozonization for rearing seawater in land-based culture system has recently been utilized for disinfection of pathogenic microorganisms and improvement of water quality. This study was conducted to examine the effects of total residual oxidants (TRO) in ozone-treated seawater on survival, blood parameters, osmolality and oxygen consumption, and gill tissue of the flounder. Paralichthys olivaceus. Experiments were carried out with the starved flounder of 12~19 cm in total length at $20^{\circ}C$. The 48-hr and 96-hr $LC_{50}$ for the flounder amounts to 26.4 ppb and 22.3 ppb, respectively. With increase of TRO concentration from 24 to 39 ppb, the values of hematocrit, hemoglobin concentration, red blood cell count and osmolality of the flounder with respect to exposure time were significantly elevated, however, the oxygen consumption rates decreased. In the case of the fish exposed to 13 ppb for 96 hrs, blood glucose increased with an elapse of exposure time, while survival rate was 100%. Death apparently resulted by massive destruction of gill lamellar epithelium, severe osmotic imbalance and the lack of oxygen uptake. The results of this experiment indicated that to protect aquaculture organisms, the ozone-treated seawater should not contain any residual oxidants, and that relatively long-term exposure to TRO of low concentration can impact on survival and physiological conditions of the flounder.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.408-417
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• 2017

This study was conducted to examine the influence of the nurse staffing level on the level of in-hospital death and infection in cancer patients who received surgery. Secondary data were used and the subjects of this study were 24,510 patients who received surgery for six types of cancer with a high postoperative mortality rate in the first half of 2012 at 260 hospitals. Simple logistic and GEE multiple logistic regression analyses were used. After adjusting for the patient and hospital characteristics, a greater likelihood of dying was found in the nurse staffing level 2-3 group (odds ratio [OR], 1.46; 95% confidence interval [CI], 1.00-2.11) and in the level 6-7 group (OR, 3.28; 95% CI, 1.87-5.74) compared to the level 0-1 group. The likelihood of in-hospital infection increased with each additional bed per nurse, being 6.63 times higher (95% CI, 3.00-14.62) in the level 2-3 group, 5.79 times higher (95% CI, 1.88-17.78) in the level 4-5 group, and 8.4 times higher (95% CI, 1.82-38.84) in the level 6-7 group, as compared to the level 0-1 group. A lower nurse staffing level was associated with higher in-hospital death and infection levels. This shows that an appropriate nurse staffing level is associated with superior postoperative cancer patient outcomes. Policies for providing adequate nurse staffing should be maintained for the sake of ensuring improved care quality and patient safety.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup2
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• pp.228-234
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• 2001

Objective : The goal of this study was to identify variables that were predictive of recurrence in primary intracranial ependymomas. Methods : We analyzed variables affecting recurrence in 30 patients with primary intracranial ependymomas. Age, location, CSF cytology, seeding on neuroimaging study, tumor grade, extent of surgery, use of chemotherapy, chemotherapy regimen, use of radiotherapy, and radiotherapy field were entered to test their impacts on recurrence. Results : Follow-up ranged from 2 to 110 months. Tumors were recurred at the primary tumor site only in 13 patients (43.3%). The overall average recurrence free period was 55 months, with overall recurrence free rates at 3 and 6 years of 61.0% and 20.9%, respectively. Extent of surgery was the strongest variable affecting recurrence. The median recurrence free period and 3-year recurrence free rate were 72 months and 78.4% for patients having complete excision and 33 months and 0% for those having incomplete excision(p=0.05). Other prognostic variables like age, location, tumor grade, use of chemotherapy, and use of radiotherapy did not affect recurrence(p=0.2848, 0.7899, 0.1714, 0.2157, 0.7076, respectively). Conclusions : Intracranial ependymomas have a propensity to recur after treatment, and recurrence at the primary site is still the main obstacle to cure. Among various variables, only extent of resection had the strongest impact on recurrence. Additional studies may still be needed to precisely define the prognostic variables on recurrence in intracranial ependymomas.

• Restorative Dentistry and Endodontics
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• v.35 no.6
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• pp.436-444
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• 2010

Objectives: This study aimed to assess prospectively the clinical outcome of nonsurgical endodontic treatment and identify patient- and tooth-related factors, rather than treatment-related factors, that were the best predictors of this outcome. Materials and Methods: The inception cohort comprised 441 teeth (320 patients) and 175 teeth (123 patients) were followed up for 1-2 years. Age, gender, presence of medical disease, number of canals, previous endodontic treatment, presence of sensitivity and pain, pulp vitality, swelling or sinus tract of pulpal origin on the gingiva, periapical radiolucency and tendency of unilateral bite on the affected tooth were recorded at treatment start. Results: The outcome was classified on the basis of periapical radiolucency as healed or non healed. The overall healed rate in these cases, including nonsurgical retreatment, was 81.1%. Four tooth-related factors had a negative impact in the bivariate analysis: previous endodontic treatment, necrotic pulp, preoperative gingival swelling or sinus tract of pulpal origin, and preoperative periapical radiolucency. Stepwise logistic regression analysis including patient-, tooth-related factors and level of the root canal filling as a treatment-related factor showed that preoperative gingival lesion (odds ratio [OR]: 4.4; p = 0.005), preoperative periapical radiolucency (OR: 3.6; p = 0.011), and $\leq$ 1-2 mm under root filling length (OR: 9.6; p = 0.012) were significant predictors of failure. Conclusions: A preoperative gingival lesion of pulpal origin can influence the outcome of nonsurgical endodontic treatment in addition to preoperative periapical radiolucency.

• Journal of the Korea Management Engineers Society
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• v.23 no.4
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• pp.49-72
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• 2018

Before the financial crisis of 1997 in Korea, many industrial sectors across the country have achieved remarkable economic growth since the 1970s because of the development of large-scale equipment industries such as civil engineering, steel, construction and chemical industries. However, after the financial crisis, the economic growth rate has slowed down. Also, the global recession and the rise of China in the global business environment have led to a long-term recession in the national industry as a whole. In current economic environment, it is not easy for the companies even having excellent resources to continue its competitive advantage. Moreover, the chemical industry, which has an influence as a basic industry of other industries, misses the point of transformation into a high value-added industry, as shown in previous research. In order to meet the rapidly changing global business environment, Korean chemical companies should have a dynamic capabilities which to rapidly reallocate and consolidate the resources and capabilities they possess. The dynamic capabilities to convert, rearrange and develop the resources possessed by the company in the direction of creating high added value and to promptly search for, absorb, transform and fuse newly required capabilities and resources should be continuously applied to Korean chemical companies. It is the core competence to secure competitive advantage. In order to secure the dynamic capabilities of the company, the dynamic capabilities of individual employees should be strengthened and employees should be able to demonstrate their own leadership so that they can proactively work and self-manage in a positive direction. Previous studies have focused mainly on the dynamic capabilities of firms. However, the competence of the human resources that make up the enterprise leads to the capabilities of the enterprise, and the human resources themselves are also important corporate resources. This paper focuses on the dynamic capabilities of individuals and strives to clarify the causal relationship between dynamic capabilities, self-leadership, and organizational effectiveness which have direct or indirect effects on management outcome. The reasons for choosing the chemical industry are based on the fact that a domestic chemical companies are in a long-term recession, and they lacks a innovation and value creation capabilities. Also, chemical industry has a large impact on the national economy.