• The Journal of Asian Finance, Economics and Business
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• v.6 no.1
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• pp.281-288
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• 2019

This study examines the relationship between R&D intensity and disclosure. R&D activities are essential in bringing innovation to companies. However, R&D activities are naturally uncertain and increase information asymmetry. Thus, firms with high R&D activities are more likely to have the incentive to communicate the potential of R&D investment to the market through voluntary disclosure and, concurrently, resolve information asymmetry. Meanwhile, incentives to less voluntary disclosure exist because of the proprietary cost and the risk of competitiveness loss. Furthermore, the uncertainties inherent in R&D activities caused the possible decrease in the information accuracy. For the two opposing views, this study investigates the relationship between R&D intensity and disclosure frequency using the Regulation Fair Disclosure data in Korea. Moreover, the relationship between R&D intensity and usefulness of the information disclosed is also examined. Using firm sample listed in the 2011-2016 Korea Stock Market, results show that firms with high R&D intensity make disclosures more frequent. Subsequently, the analysis using forecast sample shows that management forecast error is higher in firms with high R&D intensity. This research contributes to the existing literature by presenting evidence that R&D intensity is a significant factor affecting manager's disclosure behavior and information usefulness.

• Journal of the Korean GEO-environmental Society
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• v.20 no.12
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• pp.27-32
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• 2019

Disaster Safety Management Information standardization and harmonization simplifies the process of disaster management (prevention, preparedness, response and recovery) to increase the efficiency of disaster management, it is necessary to minimize the people's life and property damage. Disaster safety standardization is to standardize disaster safety information in the past to respond to an uncertain future and systematically manage disaster safety accordingly. This study developed a standard code system to utilize disaster safety information such as earthquake, fire, and fine dust, which are of social interest among various and complex environmental disasters. It aims to support practitioners to conduct efficient disaster tasks in the event of a disaster.

• Structural Engineering and Mechanics
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• v.56 no.2
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• pp.201-221
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• 2015

The fatigue damage problems are frequently encountered in the design of civil engineering structures. A realistic and accurate fatigue life prediction is quite essential to ensure the safety of engineering design. However, constructing a reliable fatigue life prediction model can be quite challenging. The use of traditional deterministic approach in predicting the fatigue life is sometimes too dangerous in the real practical designs as the method itself contains a wide range of uncertain factors. In this paper, a new fatigue life prediction method is going to be proposed where the residual strength is been utilized. Several cumulative damage models, capable of predicting the fatigue life of a structural element, are considered. Based on Miner's rule, a randomized approach is developed from a deterministic equation. The residual strength is used in a one to one transformation methodology which is used for the derivation of the fatigue life. To arrive at more robust results, fuzzy sets are introduced to model the parameter uncertainties. This leads to a convoluted fuzzy based fatigue life prediction model. The developed model is illustrated in an example analysis. The calculated results are compared with real experimental data. The applicability of this approach for a required reliability level is also discussed.

• Nuclear Engineering and Technology
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• v.52 no.5
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• pp.1079-1092
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• 2020

A parametric study of several parameters relevant to design safety on the spent nuclear fuel (SNF) rod response under a drop accident is presented. In the view of the complexity of interactions between the independent safety-related parameters, a factorial design of experiment is employed as an efficient method to investigate the main effects and the interactions between them. A detailed single full-length fuel rod is used with consideration of post-irradiated fuel conditions under horizontal and vertical free-drops onto an unyielding surface using finite-element analysis. Critical drop heights and critical g-loads that yield the threshold plastic strain in the cladding are numerically estimated to evaluate the fuel rod structural resistance to impact load. The combinatory effects of four uncertain parameters (pellet-cladding interfacial bonding, material properties, spacer grid stiffness, rod internal pressure) and the interactions between them on the fuel rod response are investigated. The principal finding of this research showed that the effects of above-mentioned parameters on the load-carrying capacity of fuel rod are significantly different. This study could help to prioritize the importance of data in managing and studying the structural integrity of the SNF.

• Journal of Gastric Cancer
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• v.21 no.3
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• pp.236-245
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• 2021

Purpose: The numeric N stage has replaced the topographic N stage in the current tumor node metastasis (TNM) staging in gastric carcinoma. However, the usefulness of the topographic N stage in the current TNM staging system is uncertain. We aimed to investigate the prognostic value of the topographic N stage in the current TNM staging system. Materials and Methods: We reviewed the data of 3350 patients with gastric cancer who underwent curative gastrectomy. The anatomic regions of the metastatic lymph nodes (MLNs) were classified into 2 groups: perigastric and extra-perigastric. The prognostic value of the anatomic region was analyzed using a multivariate prognostic model with adjustments for the TNM stage. Results: In patients with lymph node metastasis, extra-perigastric metastasis demonstrated significantly worse survival than perigastric metastasis alone (5-year survival rate, 39.6% vs. 73.1%, respectively, P<0.001). Extra-perigastric metastasis demonstrated significantly worse survival within the same pN stage; the multivariate analysis indicated that extra-perigastric metastasis was an independent poor prognostic factor (hazard ratio=1.33; 95% confidence interval=1.01-1.75). The anatomic region of the MLNs improved the goodness-of-fit (likelihood ratio statistics, 4.57; P=0.033) of the prognostic model using the TNM stage. Conclusions: The anatomic region of MLNs has an independent prognostic value in the numeric N stage in the current TNM staging of gastric carcinoma.

• Wind and Structures
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• v.28 no.2
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• pp.111-128
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• 2019

In this paper an octagon plan shaped building (study building) in presence of three square plan shaped building is subjected to boundary layer wind flow and the interference effects on the study building is investigated using Computational fluid dynamics. The variation of the pressure coefficients on different faces of the octagon building is studied both in isolated and interference conditions. Interference Factors (IF) are calculated for different faces of the study building which can be a powerful tool for designing similar plan shaped buildings in similar conditions. A metamodel of the IF, in terms of the distances among buildings is also established using Response Surface Method (RSM). This set of equations are optimized to get the optimum values of the distances where the IF is unity. An upstream Interference zone for this building setup and wind environment is established from these data. Uncertainty principle is also utilised to determine the optimum positions of the interfering buildings considering the uncertain nature of wind flow for minimum interference effect. The proposed procedure is observed to be computationally efficient in deciding optimum layout at buildings often required in city planning. The results show that the proposed RSM-based optimization approach captures the interference zone accurately with substantially less number of experiments.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.5
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• pp.73-80
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• 2018

At the early stages of development of high-speed propulsion systems, associated uncertainties cannot be easily modeled into probabilistic distributions, owing to the lack of test data, cost, and difficulty of simulating real-flight environments on the ground. To tackle this issue, in this research, the combustion efficiencies of dual-combustion ramjet engines are assumed to have been provided by experts and quantified by evidence theory. Using quantified uncertainty, the inlet area and combustor exit are optimized while satisfying reliability margins of thrust and thermal choking. The result shows a reasonable design of the engine under uncertain circumstances.

• Journal of Information Technology Services
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• v.19 no.6
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• pp.31-53
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• 2020

The traditional media ecosystem is facing major changes with the expansion of over-the-top (OTT) services. While the percentage of people cutting the cord has already exceeded the percentage of people subscribing to pay TV services in the United States, due to the unique characteristics of the Korean market, it is uncertain whether the cord-cutting trend will have an impact on the Korean media industry despite of the advantages of OTT services. Accordingly, this study has directly determined the beneficial and sacrificial factors of switching to OTT services, as well as the personal and external influences behind the Korean OTT service users' intention to switch. To achieve this, the Value-based Adoption Model (VAM) was used to measure the benefits of OTT services with regards to their content and systems, as well as measure the financial and procedural switching costs of cord-cutting; further, personal innovativeness and consumers' social image were added as external variables. The results of this study showed that consumers take the content and system quality of OTT services and procedural switching costs and into consideration, and that their intention to switch was based on social image. These results could serve as data for consumer analysis regarding the expansion of OTT services into the Korean media industry, and also provide the strategic basis for preparing for sudden changes that may occur in the media ecosystem due to cord-cutting.

• Journal of Oriental Neuropsychiatry
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• v.33 no.2
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• pp.181-214
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• 2022

Pediatric epilepsy, a chronic, recurrent brain disorder, is the most common neurological disorder in children. Its prevalence is increasing. Early management is very important since 30~40% of cases persist into adulthood. To provide basic data for future clinical research on pediatric epilepsy using Korean medicine treatment and cooperation between Western medicine doctors and Korean medicine doctors, we reviewed recent clinical research in traditional Chinese medicine (TCM) using herbal medicine for pediatric epilepsy. A total of 23 articles (1 clinical practice guideline, 3 systematic reviews, 15 randomized controlled trials (RCTs), and 4 non-RCTs) were reviewed in this study. The authors summarized characteristics of included studies regarding study subjects, diagnostic tools, pattern identification tools, treatment period, evaluation tools, detail of herbal medicines, treatment effects, and adverse events. Combination therapy using both herbal medicine (HM) and anti-epileptic drugs (AEDs) was performed more frequently than herbal medicine alone. Liver-pacifying medicinal, water-draining medicine, and orifice-opening medicine were frequently used. The main single HMs were Cheonma, Boglyeong, Jogudeung, and Seogchangpo. Combined therapy using HM and AEDs had significant benefits in improving total effective rate. It also appeared to be safer than AEDs. However, since the quality of clinical trials was poor and only studies in the last 10 years were included, the clinical evidence was uncertain. Finally, the authors provided limitations of this study and several suggestions for future research based on our analysis results.

• Journal of Navigation and Port Research
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• v.46 no.5
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• pp.419-426
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• 2022

This study aimed to identify new routes for transporting automobiles from Korea to Mongolia by comparing them with the existing route. At present, a route from the Incheon Port through the Tianjin Port to Zamiin-Uud is commonly used to transport containerized cargo from Korea to Mongolia. This study examined five possible logistics routes from Korea to Mongolia using a time/cost-distance methodology based on real data. Through consecutive discussions with importers and freight forwarders in Mongolia, the potential routes were selected and costs, distance, and lead time were evaluated to provide additional route options for automobile logistics from Korea to Mongolia. The results indicated that each route could be ranked in terms of the total cost while the lead time for all options in the present COVID-19 period is 2 - 4 months, with no difference among the routes. In addition, although the confidence index of all routes was not impressive, route 3 was the most preferred option, followed by route 1. However, the study results cannot provide the answer to the question of "which route is more attractive for transporting automobiles from Korea to Mongolia." This limitation notwithstanding, this study provides real information on the critical factors of distance, cost, and lead time in terms of the selected transportation routes so that importers and exporters can compare the routes in terms of the priority of each factor in uncertain logistics environment.