• Journal of the Optical Society of Korea
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• 제17권5호
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• pp.447-453
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• 2013

A micro zoom system without moving elements by use of two liquid lenses is designed and optimized in this paper. The zoom equations of the system composed of two liquid lenses are deduced. The structure parameters including radius and thickness of a conical double-liquid electrowetting based lens are analyzed and calculated. Because the liquid thickness varies non-linearly with the radius of the interface, it's very difficult to optimize a real liquid lens using commercial optical design software directly. Through the Application Programming Interface (API) of the optical design software CODE V, a zoom system with two real electrowetting based liquid lenses is modeled and optimized. A two-liquid-lens zoom system without moving elements, with a zoom factor of 1.8 and a compact structure of 10 mm is designed for illustration. This can be useful for the camera design of mobile phones, tablets and so on. And this paper presents a convenient way of designing and optimizing a zoom system including liquid lenses by commercial optical design software.

• 한국가시화정보학회지
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• 제14권3호
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• pp.22-27
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• 2016

A sweeping jet actuator (SJA) is an instrument generating pulsing jets with no moving elements. Because of its simple design and high durability to shock and vibration, SJA has recently drawn increasing attention for the application to flow control such as aerodynamic control of a wing and thrust vectoring of a jet engine. However, experimental and numerical studies on SJA have been limited to internal flow structure of SJA. In this study, we investigated the flow structure and its variation in the outlet of SJA. We carried out the experiment to understand the flow structures using PIV (Particle Image Velocimetry). The flow structure varies with a degree of the outlet and volume flow rate. There is leaking process during half jetting cycle. The process of the main jet can occur because the jet moving time increased from one side to the other side.

• International Journal of Aeronautical and Space Sciences
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• 제3권2호
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• pp.82-87
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• 2002

Aerodynamic analysis of NACA wings moving with a constant speed over guideways are performed using an indirect boundary element method (potential-based panel method). An integral equation is obtained by applying Green's theorem on all surfaces of the fluid domain. The surfaces over the wing and the guideways are discretized as rectangular panel elements. Constant strength singularities are distributed over the panel elements. The viscous shear layer behind the wing is represented by constant strength dipoles. The unknown strengths of potentials are determined by inverting the aerodynamic influence coefficient matrices constructed by using the no penetration conditions on the surfaces and the Kutta condition at the trailing edge of the wing. The aerodynamic characteristics for the wings flying over nonplanar ground surfaces are investigated for several ground heights.

• 건축역사연구
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• 제11권4호
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• pp.99-115
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• 2002

Centered on Durand and Le Corbusier, this study analyses the changing status of the grid and axis in modern architecture. In the Renaissance, the taxis grid operated as a contour grid, defining the elements and space of the building as part of closed harmonized world. In his Pre'cis des lec., ons d'architecture, Durand provides the most explicit demonstration of a new modem grid in which its lines function as spatial and structural axes. In principle these axes are coordinates for the placements of a priori elements but in Beaux-Arts practice, as Durand himself acknowledged, they involve a simultaneous process in which the spatial axis sets up the basic parti and the structural axis is developed into the building's poche'. As a coordinate, Durand's grid provides a place for the 'subject' to enter the architectural process. At the same time, it is the object of the subject's gaze, the dense site of the subject's transformative actions. Though Le Corbusier is noted for his frequent attacks on the academic system, his architecture should be seen within the continuity of the classical tradition. He redefines the Beaux-Arts axis as a moving and seeing observer, and continues the discipline of the plan, the essential discipline of the Beaux-Arts system. In his dialectics, an intellectual scheme which extends to his commentators, the intention and will of the subject must come in tune with the objective material form of the building. Like Durand, Le Corbusier's axis provides the medium for the subject to enter. Unlike the Beaux-Arts system, however, Le Corbusier's mobile subject no longer has a holistic view of the building previously provided by the central axis. If there is a parti for Le Corbusier, it consists of the domino grid as a potential, but nonetheless, tangible form. In comparison with the Beaux-Arts structural grid, his gaze no longer lingers on their lines because they no longer constitute a formal process tied to the development of a thick articulated structure. Le Corbusier's grid constitutes a 'loose' form, one that breaks down the hierarchical nature of the Beaux-Arts system.

• 한국유통학회지:유통연구
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• 제2권1호
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• pp.197-213
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• 1997

It is becoming very difficult for a single company to perform every process and activity required to bring its product or service to market in a competitive manner. Consequently, we are observing a dramatic paradigm shift, with companies moving from performing all activities in-house to selective outsourcing for non-core elements of their business. Through outsourcing, companies can focus on their core competencies, reduce costs, improve quality and increase flexibility. Companies today can no longer afford to ignore the potential opportunities realized through mutually beneficial outsourcing relationships with third-party suppliers. The outsourcing opportunities exist in almost every business process. Many successful companies have implemented effective outsourcing relationships with third party suppliers to gain competitive advantage in a wide range of areas. However, in terms of logistics, it is not so easy to find those companies in our country. Consequently, this paper reviews previous researches and describes several topics in third party logistics such as advantages and disadvantages, how can we select third party suppliers, and so on.

• 한국주거학회논문집
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• 제15권1호
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• pp.75-84
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• 2004

As the advent of an aging society, housing for the elderly has been of greater concern. Since the majority of the elderly prefers to live in their own familiar houses rather than moving to new ones, this study is concerned with the ways of the effective use and maintenance of exiting houses from the viewpoint of their independent living. The data was analyzed with frequency, percentage, mean, correlation, and multiple regression using the SPSS 10.0 for Windows. The findings from the study are: The general satisfaction rate of Interior Design Affordance(IDA) was-evaluated about the average. Among the items of IDA, behavioral facilitation was found most satisfactory, and perceptual maintenance, physilogical maintenance, and social facilitation were followed in satisfaction level. Although there had been many elements of serious safety dangers, no home modification was made in the elderly households who live alone or/with spouse.

• Structural Engineering and Mechanics
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• 제22권5호
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• pp.563-574
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• 2006

This paper studies mechanical behavior of the superelastic shape memory alloy (SMA) rods in terms of local deformations and time via tensile loading-unloading cycles for both ends fixed end constraints. Besides the unique stress induced martensitic transformation (SIMT), SMA's time dependent behavior when it is in mixed-phase condition upon loading and unloading, also need careful attention with a view of investigating the local deformation of the structural elements made of the same material. With this perspective, the so-called stress-relaxation tests have been performed to demonstrate and investigate the local strains-total strains relationships with time, particularly, during the forward SIMT. Some remarkable phenomena have been observed pertaining to SIMT, which are absent in traditional materials and those unique phenomena have been explained qualitatively. For example, at the stopped loading conditions the two ends (fixed end and moving end of the tensile testing machine) were in fixed positions. So that there was no axial overall deformation of the specimen but some notable increase in the axial local deformation was shown by the extensometer placed at the middle of the SMA specimen. It should be noted that this peculiar behavior termed as 'inertia driven SIMT' occurs only when the loading was stopped at mixed phase condition. Besides this relaxation test for the SMA specimens, the same is performed for the mild steel (MS) specimens under similar test conditions. The MS specimens, however, show no unusual increase of local strains during the stress relaxation tests.

• The Journal of Asian Finance, Economics and Business
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• 제8권4호
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• pp.43-54
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• 2021

The study evaluates India's technological advancement, which has created a range of opportunities for consumers to enter into digital payment space. Demonetization in India has forced all consumers and companies to embrace and create cashless digital payment platforms. The cashless economy scenario involves various factors for its adoption such as reach, availability and awareness. This study considers factors responsible for adopting new digital payment technologies in India's different regions across various consumers. The study includes descriptive statistics and variance analysis (ANOVA) to identify elements to achieve maximum satisfaction. The research collects data from 250 respondents living in India, experiencing digital payments and online transactions. The data is collected through a structured questionnaire and critically analyzed using statistical analysis. The data has been analyzed with no sectorial biases and tracked by creating real-time indications. The study uses various hypotheses after taking responses from a sample of respondents. Cronbach's Alpha analysis is also used to determine the validity and reliability of the data. The study illustrates the complete shift of consumer behavior from cash to a cashless economy. A certain number of factors are shown to directly influence the rate of such a shift toward digital transactions in India.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.404-409
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• 2004

To maximize the productivity in machining molds and dies, machine tools should operate at high speeds. During the high speed operation of moving frames or spindles, vibration problems are apt to occur if the machine tool structures are made of conventional steel materials with inferior damping characteristics. However, self-excited vibration or chatter is bound to occur during high speed machining when cutting speed exceeds the stability limit of machine tool. Chatter is undesirable because of its adverse effect on surface finish, machining accuracy, and tool life. Furthermore, chatter is a major cause of reducing production rate because, if no remedy can be found, metal removal rates have to be lowered until vibration-free performances is obtained. Also, the resonant vibration of machine tools frequently occurs when operating frequency approaches one of their natural frequencies because machine tools have several natural frequencies due to their many continuous structural elements. However, these vibration problems are closely related to damping characteristics of machine tool structures. The polymer concrete has high potential for machine tool bed due to its good damping characteristics with moderate stiffness. This paper presents the use of polymer concrete and sandwich structures to overcome vibration problems. Also, co-cure bonding method for functional part mounting was exhibited experimentally, by which manufacturing time and cost for polymer concrete bed will be remarkably reduced.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.113-116
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• 2003

To maximize the productivity in machining molds and dies, machine tools should operate at high speeds. During the high speed operation of moving frames or spindles, vibration problems are apt to occur if the machine tool structures are made of conventional steel materials with inferior damping characteristics. However, self-excited vibration or chatter is bound to occur during high speed machining when cutting speed exceeds the stability limit of machine tool. Chatter is undesirable because of its adverse effect on surface finish, machining accuracy, and tool lift. Furthermore, chatter is a major cause of reducing production rate because, if no remedy can be found, metal removal rates have to be lowered until vibration-free performances is obtained. Also, the resonant vibration of machine tools frequently occurs when operating frequency approaches one of their natural frequencies because machine tools have several natural frequencies due to their many continuous structural elements. However, these vibration problems are closely related to damping characteristics of machine tool structures. This paper presents the use of polymer concrete and sandwich structures to overcome vibration problems. The polymer concrete has high potential for machine tool bed due to its good damping characteristics with moderate stiffness. In this study, a polymer concrete bed combined with welded steel structure i.e., a hybrid structure was designed and manufactured for a high-speed gantry-type milling. Also. its dynamic characteristics were measured by modal tests.