• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.23-29
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• 2009

A sand-cone method is commonly used to determine the density of the compacted soils. This method uses a calibration container to determine the bulk-density of the sand for use in the test. The density of the test or compacted soil is computed on the assumption that the calibration container has approximately the same size or volume and allows the sand to fall approximately the same height as a test hole in the field. However, in most cases the size or shape of test hole is not exactly the same as the calibration container. There is certain discrepancy between sand particle settlement or arrangement in the laboratory calibration and in the field testing, which may cause an erroneous determination of in-situ density. The sand filling process is simulated in the laboratory and its effect on the determination of density is investigated. Artificially-made holes with different heights and bottom shapes are prepared to simulate various shapes of the test hole in the field. The sands with different gradations are used in the testing to examine how sand grain size influences the determination of density in the field.

• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.1
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• pp.57-70
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• 2012

This article presents a numerical investigation concerning the effect of two kinds of axially progressing internal flows (namely, upward and downward) on fluid.structure interaction (FSI) dynamics about a marine riser model which is subject to external shear current. The CAE technology behind the current research is a proposed FSI solution, which combines structural analysis software with CFD technology together. Efficiency validation for the CFD software was carried out first. It has been proved that the result from numerical simulations agrees well with the observation from relating model test cases in which the fluidity of internal flow is ignorable. After verifying the numerical code accuracy, simulations are conducted to study the vibration response that attributes to the internal progressive flow. It is found that the existence of internal flow does play an important role in determining the vibration mode (/dominant frequency) and the magnitude of instantaneous vibration amplitude. Since asymmetric curvature along the riser span emerges in the case of external shear current, the centrifugal and Coriolis accelerations owing to up- and downward internal progressive flows play different roles in determining the fluid.structure interaction response. The discrepancy between them becomes distinct, when the velocity ratio of internal flow against external shear current is relatively high.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4731-4742
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• 2022

RBMK fuel assemblies differ from other LWR FA due to a specific arrangement of the fuel rods, the low enrichment, and the used burnable absorber - erbium. Therefore, there is a challenge to adapt modeling tools, developed for other LWR types, to solve RBMK problems. A set of 10 different depletion simulation schemes were tested to estimate the impact on reactivity and spent fuel composition of possible SCALE code options for the neutron transport modelling and the use of different nuclear data libraries. The simulations were performed using cross-section libraries based on both, VII.0 and VII.1, versions of ENDF/B nuclear data, and assuming continuous energy and multigroup simulation modes, standard and user-defined Dancoff factor values, and employing deterministic and Monte Carlo methods. The criticality analysis with burn-up credit was performed for the SFP loaded with RBMK-1500 FA. Spent fuel compositions were taken from each of 10 performed depletion simulations. The criticality of SFP is found to be overestimated by up to 0.08% in simulation cases using user-defined Dancoff factors comparing the results obtained using the continuous energy library (VII.1 version of ENDF/B nuclear data). It was shown that such discrepancy is determined by the higher U-235 and Pu-239 isotopes concentrations calculated.

• Journal of Arbitration Studies
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• v.34 no.2
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• pp.27-44
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• 2024

The lack of consistency and predictability of arbitral awards in the Investor-State Dispute Settlement ("ISDS") mechanism has long been a subject of criticism. In international investment disputes, arbitral tribunals have frequently come up with different interpretations and results on similar investment agreement provisions. The arbitral tribunal's inconsistent decisions raised concerns not only among the parties to the investment dispute but also amongthe arbitral tribunals in other cases, which ultimately led to legal inconsistencies in international investment law. Arbitration awards may have some degree of disagreement in interpretation. However, the systemic inconsistencies that pervade ISDS risk undermining the purpose of the investment agreement system, which is to provide a predictable and stable framework to protect andpromote foreign investment while maintaining a balance with host state regulations. Therefore, this study proposes a plan to resolve this discrepancy and review standards for practical application. Reform of the ISDS mechanism could be a viable option to reduce, to some extent, the inconsistencies in interpretation, if not completely eliminate them. Reforms such as establishingguidelines, promoting cooperation between arbitral tribunals, and codifying the norms of the agreement can provide a means of reducing interpretive inconsistencies and strengthening the legitimacy of the ISDS mechanism. Reforming the ISDS mechanism will require all stakeholders to carefully consider the issues and the scope, nature, and feasibility of eachpotential reform.

• Journal of Korea Multimedia Society
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• v.10 no.12
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• pp.1539-1550
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• 2007

As XML is increasingly used for representing and exchanging data, relational database systems have been trying extend their features to handle XML documents XML documents can be stored in a column with XML data type like primitive types. The shredding method, which is one of the traditional methods for storing and managing XML documents in RDBMS, is still useful and viable although it has some drawbacks due to the structural discrepancy between XML and relational databases. This method may be suitable for data-centric XML documents with simple schema. This paper presents the extended version of the Association inlining method that is based on inlined shredding and compares the performance of querying processing to that of XML type method of conventional relational database systems. The experiments showed that in most cases our method resulted in better performance than the other method based on XML data type. This is due to the fact that our shredding method keeps and uses the order and path information of XML documents. The path table has the information of the corresponding table and column for each distinct path and the structure information of the XML document is extracted and stored in data tables.

• Journal of the Korean Society of Safety
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• v.31 no.4
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• pp.120-125
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• 2016

Usually, a risk can be expressed as a product of likelihood and consequence of a hazard factor. Therefore, conventional risk assessment is carried out by frequency analysis and severity analysis, in turns. However, it is well known that intuitive thinking is another excellent way of thinking of human beings. This study aimed to confirm whether there exist any difference in risk assessment results derived by two different procedures - intuitive and analytical. Thus, the present study showed 10 different illustrations to 30 undergraduate students. Their responses were organized as fuzzy membership functions, and summarized as risk assessments, and compared. The results were also verified with the help of statistical hypothesis testing, which showed no significant difference. On the contrary, however, similarity measure used in fuzzy set theory was not credible as anticipated. Many cases failed to satisfy statistical hypothesis even with similarity measure higher than 0.60 so that only a trend could be accepted. In addition, a subject showed a somewhat consistent logical discrepancy in his response, which implied the necessity of sincere analysis in fuzzy formulations.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.69-73
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• 2000

We systematically analyze the influence of fracture junction, solute transfer characteristics on transport patterns in discrete, two-dimensional fracture network models. Regular lattices and random fracture networks with power-law length distributions are considered in conjunction with particle tracking methods. Solute transfer probabilities at fracture junctions are determined from analytical considerations and from simple complete mixing and streamline routing models. For regular fracture networks, mixing conditions at fracture junctions are always dominated by either complete mixing or streamline routing end member cases. Moreover bulk transport properties such as the spreading and the dilution of solute are highly sensitive to the mixing rule. However in power-law length networks there is no significant difference in bulk transport properties, as calculated by assuming either of the two extreme mixing rules. This apparent discrepancy between the effects of mixing properties at fracture junctions in regular and random fracture networks is explained by the statistics of the coordination number and of the flow conditions at fracture intersections. We suggest that the influence of mixing rules on bulk solute transport could be important in systematic orthogonal fracture networks but insignificant in random networks.

• Korean Circulation Journal
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• v.53 no.5
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• pp.313-327
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• 2023

Background and Objectives: Pulmonary arterial hypertension (PAH) is a rare but fatal disease. Recent advances in PAH-specific drugs have improved its outcomes, although the healthcare burden of novel therapeutics may lead to a discrepancy in outcomes between developing and developed countries. We analyzed how the epidemiology and clinical features of PAH has changed through the rapidly advancing healthcare infrastructure in South Korea. Methods: PAH was defined according to a newly devised 3-component algorithm. Using a nationwide health insurance claims database, we delineated annual trends in the prevalence, incidence, medication prescription pattern, and 5-year survival of PAH in Korea. Cumulative survival and potential predictors of mortality were also assessed among 2,151 incident PAH cases. Results: Between 2002 or 2004 and 2018, the prevalence and incidence of PAH increased 75-fold (0.4 to 29.9 per million people) and 12-fold (0.5 to 6.3 per million person-years), respectively. The proportion of patients on combination PAH-specific drug therapy has also steadily increased up to 29.0% in 2018. Among 2,151 incident PAH cases (median [interquartile range] age, 50 [37-62] years; 67.2% female), the 5-year survival rate and median survival duration were 71.8% and 13.1 years, respectively. Independent predictors of mortality were age, sex, etiology of PAH, diabetes, dyslipidemia, and chronic kidney disease. Conclusions: This nationwide study delineated that the prevalence and incidence of PAH have grown rapidly in Korea since the early 2000s. The use of combination therapy has also increased, and the 5-year survival rate of PAH in Korea was similar to those in western countries.

• Special Issue of the Society of Naval Architects of Korea
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• 2009.09a
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• pp.47-51
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• 2009

It is well known that a rudder is influential devices to help ship maintain its stable performances, such as a course-keeping and maneuverability. In the procedures of a commercial ship design proper rudder dimensions (area and shape) ensuring better ship maneuverability have been settled in an initial concept design stage performed by a preceding department, without little structural consideration. It is true that there are time discrepancy between an initial design and a structural analysis stage. Therefore structural analysis results would sometimes cause a rudder to modify its dimensions. Most of these cases, however, ship design and performance tests had been finished. In this matter, only limited modifications of redder could be carried out. Besides, these could also cause bad effects on productivity. Finally, it is necessary to develop a new program considering co-relationship between an initial rudder design and a following work, a structural strength analysis, in order to enhance productivity and minimize a rate of redesign procedures.

• Journal of Wetlands Research
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• v.6 no.1
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• pp.89-104
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• 2004

In the aftermath of nation-wide controversy over "conservation vs. development" of the costal wetland in the Saemangeum, Korea could legislate the laws of wetland conservation and costal management in 1998. Since then, the public interest in the costal mudflats and its conservation has increased greatly, but the controversy on the economic value of mutflat wetland and the futher (un)necessity of reclamation) is not yet settled. In the cases of Korea dealt, economic valuation of wetland was performed mainly in the milieu of reclamation(development) vs conservation conflict, or from interest of recreational use. Korean studies used to estimate economic value of development case and conservation case respectively and then tried to compare these two value, as is sometimes done also in other countries. But the scrutiny of the results of these studies leads us to conclude that the revealed wide discrepancy among estimated values, above all other methodological problems, denies any practical applicability to the actual policy use. Benefit transfer as a convenient alternative method of valuation can not be usable either in our cases, because there is too few reliable estimated economic values of mudflat wetlands.