• East Asian mathematical journal
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• v.32 no.3
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• pp.301-310
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• 2016

Lookback options, in the terminology of nance, are a type of exotic option with path dependency whose the payoff depends on the optimal (maximum or minimum) underlying asset's price occurring over the life of the option. In this paper, we exploit Mellin transform techniques to find a closed-form solution for European lookback options in Black-Scholes model.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.345-348
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• 2003

Overlay multicast is proposed as an alternative approach for providing muticast services. A logical infrastructure is built to form an overlay network on top of the physical layer. In this paper, we propose an efficient overlay multicast in wireless ad hoc networks. The overlay multicast tree adapts to the changes in underlying networks. The multicast tree adjusted according to the local member information.

• Journal of the Korean Operations Research and Management Science Society
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• v.13 no.1
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• pp.51-64
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• 1988

A new approach to the logical design of 4NF database shceme, which can be easily automated, is proposed. The main features of the approach are : introduction of a single attribute right hand side, extension of the concept of independent relations, semantic analysis, and adaoption of dependency matrix. The underlying viewpoints of functional relationships of the approach are different from Fagin's in that we distinguish functional and multivalued dependency in terms of cardinality. An algorithm for automatic generation of fourth normal form is presented and implemented.

• Journal of Korean Public Health Nursing
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• v.28 no.3
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• pp.495-508
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• 2014

Purpose: This study was conducted in order to evaluate the reliability, validity, sensitivity, and specificity of the Short Form of Bobath Memorial Hospital Fall Risk Assessment Scale (BMFRAS-SF). Methods: A validation study was conducted on 207 elderly patients aged over 65 who were admitted to Bobath Memorial Hospital. Fall risk scores of BMFRAS, composed of eight subscales (age, fall history, physical activity, consciousness level, communication, fall risk factors, underlying disease, and medications) were assessed from the electronic medical record. BMFRAS-SF was derived from eight subscales of the BMFRAS representing the significance between fallers and non-fallers (fall history, physical activity, fall risk factors, underlying disease, and medications). Internal consistency reliability and interrater reliability were assessed by Cronbach's alpha and kappa coefficient. Validity was assessed by Spearman correlation analysis, factor analysis. Sensitivity, specificity, positive predictive and negative predictive values, and a receiver-operating characteristic curve (ROC) were generated. Results: Fallers had significantly higher risk scores than non-fallers in fall history, physical activity, fall risk factors, underlying disease, and medication scales. The BMFRAS-SF demonstrated acceptable Cronbach's alpha (.706) and kappa coefficients of .95. The BMFRAS-SF subscales showed good convergent validity and construct validity. The BMFRAS-SF presented good sensitivity(86.7%), specificity(67.9%), positive predictive value(42.9%) and good negative predictive value(94.8%) at a cut-off score of 5. Areas under the ROC curves were .860 for the BMFRAS and .861 for the BMFRAS-SF. Conclusion: The BMFRAS-SF was proved to be reliable and valid. It could be used for time-saving assessment and evaluation of the high risks for falls in clinical practice settings.

• Human Ecology Research
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• v.58 no.2
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• pp.215-228
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• 2020

Underlying dress forms for high coverage patterns are very important in the dress industry. Size 9 from brand D was chosen according to the analysis that it was the best option because a dress should have a large allowable range in one size. The criteria for selection were the dress form with a waist circumference of 63.50 centimeters, which is close to the standard size of women in Korea. Brassieres for dresses were included to enhance the aesthetic value of the correction process in producing a basic dress pattern. An experimental torso pattern was applied to evaluate the fit and suitability of the dress form that was also later verified in the process of the dress works. Three dresses were produced and presented on the chosen study dress form. The research procedures are as follows. First, the sell-through rates and feedbacks were collected from the dress form vendor. Second, a literature survey on dresses and a dress company investigation were conducted. Third, the amount of body dimension changes due to the use of a bra in the dresses were examined. Fourth, after the correction of the dress form, the torso pattern was made by draping. Fifth, the torso experimental clothing made of muslin material was evaluated. Sixth, the dress works of the top design were presented using the size 9 basic pattern developed by brand D.

• Wind and Structures
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• v.22 no.3
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• pp.307-328
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• 2016

This paper describes an investigation of the net wind loads on solar panels and wind loads on the underlying roof surface for panels mounted parallel to pitched roofs of domestic buildings. Typical solar panel array configurations were studied in a wind tunnel and the aerodynamic shape factors on the panels were put in a form appropriate for the Australian/New Zealand Wind Actions Standard AS/NZS 1170.2:2011. The results can also be used to obtain more refined design data on individual panels within an array. They also suggest values for the aerodynamic shape factors on the roof surface under the panels, based on a gust wind speed at roof height, of ${\pm}0.5$ for wind blowing parallel to the ridge, and ${\pm}0.6$ for wind blowing perpendicular to the ridge. The net loads on solar arrays in the middle portion of the roof are larger than those on the same portion of the roof without any solar panels, thus resulting in increased loads on the underlying roof structure.

• Bulletin of the Korean Mathematical Society
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• v.39 no.1
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• pp.175-184
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• 2002

A Cellular embedding of a graph G into an orientable surface S can be considered as a cellular decomposition of S into 0-cells, 1-cells and 2-cells and vise versa, in which 0-cells and 1-cells form a graph G and this decomposition of S is called a map in S with underlying graph G. For a map M with underlying graph G, we define a natural rotation on the line graph of the graph G and we introduce the line map for M. we find that genus of the supporting surface of the line map for a map and we give a characterization for the line map to be embedded in the sphere. Moreover we show that the line map for any life of a map M is map-isomorphic to a lift of the line map for M.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 1999.03a
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• pp.161-171
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• 1999

Query language has been widely used as a convenient tool to obtain information from a database. However, users demand more intelligent query processing systems that can understand the intent of an imprecise query and provide additional useful information as well as exact answers. This paper introduces a meta-database and presents a query processing mechanism that supports a variety of intelligent queries in a consistent and integrated way. The meta-database extracts data abstraction knowledge form an underlying database on the basis of a multilevel knowledge representation framework KAH. In cooperation with the underlying database, the meta-database supports four types of intelligent queries that provide approximately or conceptually equal answers as well as exact ones.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.279-282
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• 1997

Bayesian reconstruction methods for emission computed tomography have been a topic of interest in recent years, partly because they allow for the introduction of prior information into the reconstruction problem. Early formulations incorporated priors that imposed simple spatial smoothness constraints on the underlying object using Gibbs priors in the form of four-nearest or eight-nearest neighbors. While these types of priors, known as "membrane" priors, are useful as stabilizers in otherwise unstable ML-EM reconstructions, more sophisticated prior models are needed to model underlying source distributions more accurately. In this work, we investigate whether the "thin plate" model has advantages over the simple Gibbs smoothing priors mentioned above. To test and compare quantitative performance of the reconstruction algorithms, we use Monte Carlo noise trials and calculate bias and variance images of reconstruction estimates. The conclusion is that the thin plate prior outperforms the membrane prior in terms of bias and variance.

• Journal of Oral Medicine and Pain
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• v.41 no.4
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• pp.145-154
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• 2016

Transcutaneous electrical nerve stimulation (TENS) is one of the representative physiotherapical modalities used for the treatment of various musculoskeletal disorders by the application of electrical stimuli. In dental practice, it has long been used in the treatment of acute and chronic orofacial pain conditions including temporomandibular disorders. TENS is the delivery of therapeutic electrical stimuli with a variety of electrical intensity, frequency and duration to stimulate peripheral nerve through surface electrodes with various form and placement. While controversy still remains over the clinical effectiveness and application of TENS, basic understanding of its electrical properties and the expected biological reactions is important to increase the therapeutic effect and decrease the risk of possible side effects. This review, therefore, focuses on basic understanding of TENS including its underlying mechanisms and stimulation parameters.