• 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.

• Journal of applied mathematics & informatics
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• v.5 no.1
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• pp.223-233
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• 1998

This paper is concerned with the problem of existence of solutions to the initial value problem u'(t) = A(t, u(t)), u(a) = z in a probabilistic normed space where $A : [a,b)\;{\times}\;D->E$ is continuous, D is a closed subset of a probabilistic normed space E, and $z\;{\in}\;D$. With a dissipative type condition on A, we estabilish sufficient conditions for this initial value problem to have a solution.

• Journal of the Chungcheong Mathematical Society
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• v.36 no.4
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• pp.279-288
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• 2023

We obtain a Chandrabhan type fixed point theorem for a multimap having a non-compact domain and a weakly closed graph, and taking convex values only on a quasi-convex subset of Hausdorff locally convex topological vector space. We introduce the definition of Chandrabhan-set and find a sufficient condition for every countably condensing multimap to have a relatively compact Chandrabhan-set. Finally, we establish a new version of Sadovskii fixed point theorem for multimaps.

• Architectural research
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• v.13 no.3
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• pp.3-10
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• 2011

The Characteristics of space are determined by several factors; however, the element that determines the physical characteristic of floors, walls, and ceiling is the structure. This study constructs a wall to analyze the direct effect that the layout of an exhibition wall has on the element of the wall followed by the structural process and visibility of descriptive analysis and examples of art museums that the shift from a perceptional wall to an experiential wall affected circulation. For elements and formation methods of the wall, first, it is made up of open and closed type exhibition spaces, and it can give abundance in qualitative space rather than a quantitative aspect. Secondly, the directivity of space changes according to the development of the visible axis, thus, directly affects the change in visibility. Thirdly, the difference between spatial structure and visual structure is the difference between the visual axis and spatial structure. The wall formation type followed by the combination method, the simple visible structure, which is the type that possesses the simple combination (Room, Zone, Cluster), repeatedly uses the same size of units of space that is orderly and has few spatial axes and the classification of simple type and simple cluster type, which has few visible axes, also exists. Also, with the complex structure of the maze type it displays the reiterated form of the cluster, which is the space with disorderly combination and has much visible axes and spatial axes. Also, these can be divided into three types: 1) Maze Cluster Type, 2) Cross Road Type, and 3) Open Flexible Type. These wall types lead the various changes in circulation, and even each of the arrangement qualities of the exhibitions should be researched according to its exhibition place type.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.1
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• pp.51-60
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• 2012

Optimization procedures of performance analysis for ORC(Organic Rankine Cycle) system are established to the characteristics of low temperature heat sources such as open-type and closed-type. Effective heat recovery and heat extraction related to maximum power of the cycle as well as heat quality and thermal efficiency must be considered in the case of the open-type low temperature heat source. On the other hand, in the case of the closed-type low temperature heat source, only thermal efficiency is important due to constant heat input. In this study, thermal efficiency and exergy efficiency representing a level of close to Carnot cycle are studied, as useful index for the optimization of the ORC system. To validate the results of cycle analysis, those are compared with appropriate experimental data of ORC system as a thermal efficiency point of view.

• Design & Manufacturing
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• v.6 no.2
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• pp.59-63
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• 2012

In various industries, tactile recognition has been one of the important ways in displaying information because peoples like to touch and feel. Especially, how much the tactile information is efficiently recognizable is crucial for visually impaired persons in their daily lifes. However, existing design guidelines are insufficient to lead good tactile recognition. In this study, an experiment was performed to investigate proper tactile shapes (relievo / intaglio vs. filled / unfilled), sizes and depths for efficient tactile recognition. Moreover, this study scrutinized whether the recognition speed or error was varied depending on the type of displayed symbols (open vs. closed types) in tactile. The experimental results revealed that the 'relieve-filled' shape type was more rapidly recognizable than the other shapes, and the 'closed' type symbols (e.g., ${\square }$. ${\bigcirc}$) were more robustly recognizable than the 'open' type symbols (e.g, +, ^). Several design guidelines were presented based on the results. These guidelines can be applied to the design of tactile buttons in the devices that users should control them without visual attention, such as car steering wheels or MP3 players.

• Journal of Chest Surgery
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• v.11 no.3
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• pp.342-347
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• 1978

A 8 year old male was admitted to the Department of Thoracic Surgery, Korea University Hospital on June 22, 1978. The chief complaints were cyanosis and exertional dyspnea since at birth. EKG shows BVH and dextrocardia, phonocardiogram revealed the accentuation of second heart sound in aortic area. Echocardiogram from the left ventricle to the base of the heart, there is a discontinuity between the ventricular septum and the anterior aortic margin with a large aortic root & aortic overriding. His cardiac catheterization data and cardiac angiogram shows situs inversus totalis, dextrocardia, right aortic arch, large ventricular septal defect etc., and finally diagnosed Truncus Arteriosus. Edwards type IV with retrograde aortogram and selective bronchial angiogram. This is the first operative case reported as Rastelli operation for Truncus Arteriosus type IV in the literatures in Korea. Authors have experienced I case of Truncus Arteriosus, Edward type IV and Rastelli operation with Dacron Arterial Conduit Graft under cardiopulmonary bypass on July 3, 1978. The procedures were as follows; 2] Cardiopulmonary bypass: Origin of bronchial arteries excised from descending aorta bilaterally; defects in aorta closed. 2] Horizontal incision made high in right ventricle. 2] Ventricular septal defect [Kirklin type I+II] closed with Teflon patch. 4] Bifurcated dacron arterial graft with pericardial monocusp sutured to the bilateral pulmonary arteries. [Diameter 9 mm: Length 7 cm]. 5] Proximal end of the conduit graft anastomosed to right ventricle. [Diameter 19 mm: Length 5 cm]..Total perfusion time was 220 min. The result of operation was poor due to anastomotic leakage and increased pulmonary vascular resistance resulting acute right heart failure. The patient was died on the operation table. Literatures were briefly reviewed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.10
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• pp.1388-1394
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• 2018

In this paper, the improvement of the control response by using the error compensator to improve the stability of the control in the power conversion system is verified. Typically a closed loop control method is used to improve the control response characteristics in a traditional power conversion system and this is accomplished by generating a PWM waveform. In this paper, the newly constructed Type3 compensator to overcome the existing such as PI controller or Type2 compensator has been developed to improve the control stability of these closed loop control systems and the effectiveness of the use of error compensation devices was verified by presenting technique to improve stability and select its parameters by expanding the range of phase gains. Stability improvements are shown by the extension of the phase gain range and parameter selection techniques and the effects of using the error compensation device are verified accordingly.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.848-851
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• 2007

Recently, as the demand of the information storage devices with large storage capacity such as BD(Blu-ray Disk) and HDTV(high-definition television) is increased, the optical storage devices are also required to have fast data transfer rate and large storage capacity. To satisfy these requirements, the actuator for optical disk drive should have high flexible mode frequencies for system stability. In this paper, we suggested a moving magnet type actuator having high flexible mode frequency. However, the moving magnet type actuator does not have sufficient driving sensitivities due to the weight of its moving part. To improve driving sensitivities, we designed the model with the closed electromagnetic circuit for tracking direction. In addition, driving sensitivities and flexible mode frequencies were improved by using DOE(Design of Experiments) for magnetic circuit and modifying the lens holder. Consequently, it is confirmed that the designed model is satisfied with the desired specifications.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.335-340
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• 2005

A study on the variation of combustion characteristics by injector geometries was conducted. Coaxial swirl injectors were used. Existence of swirl chamber and variation of a nozzle length become key parameters. Injectors were identified as open, closed and mixed type by existence of swirl chamber. Variation of nozzle length was made extruding the both nozzle along the axis while other design parameters remain the same. A uni-element combustor with ablative material liner and a water cooled nozzle made by oxygen free copper with outer stainless steel casing were used.