• Journal of information and communication convergence engineering
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• v.6 no.2
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• pp.129-133
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• 2008

In this paper, modified power control algorithms are proposed for a satellite mobile communications system with ATC (ancillary terrestrial component). In order to increase system capacity and reduce the transmitting power of the user's equipment, we propose the modified power control scheme consisting of the modified closed-loop and open-loop power control. The modified CLPC (closed-loop power control) algorithm, combining the delay compensation algorithms and pilot diversity, is mainly applied to the ATC link in urban areas because it is more suitable to the short RTD (round-trip delay). In the case of rural areas where ATCs are not deployed or a signal is not received from ATCs, combining monitoring transmitting power equipment and OLPC (open-loop power control) algorithms using an efficient pilot diversity is mainly applied to the link between the user's equipment and the satellite. Two power control algorithms are applied equally to the boundary areas where two kinds of signals are received in order to ensure coverage continuity. The simulation results show that the modified power control scheme has good performance compared to conventional power control schemes in a GEO (geostationary earth orbit) satellite system with ATC.

• Smart Structures and Systems
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• v.15 no.5
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• pp.1233-1252
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• 2015

This study investigates the problem of crack detection in post-buckled beam-type structures. The beam under the axial compressive force has a crack, assumed to be open and through the width. The crack, which is modeled by a massless rotational spring, divides the beam into two segments. The crack detection is considered as an optimization problem, and the weighted sum of the squared errors between the measured and computed natural frequencies is minimized by the bees algorithm. To find the natural frequencies, the governing nonlinear equations of motion for the post-buckled state are first derived. The solution of the nonlinear differential equations of the two segments consists of static and dynamic parts. The differential quadrature method along with an arc length strategy is used to solve the static part, while the same method is utilized for the solution of the linearized dynamic part and the extraction of the natural frequencies of the cracked beam. The investigation includes several numerical as well as experimental case studies on the post-buckled simply supported and clamped-clamped beams having open cracks. The results show that several parameters such as the amount of applied compressive force and boundary conditions influences the outcome of the crack detection scheme. The identification results also show that the crack position and depth can be predicted well by the presented method.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.2
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• pp.162-170
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• 2014

A CFD(Computational Fluid Dynamics) analysis is presented to predict hydrodynamic characteristics of a marine propeller. A commercial RANS(Reynolds Averaged Navier-Stokes equation) solver, namely FLUENT, is utilized in conjunction with fully unstructured meshes around rotating propeller. Mesh generation process is greatly accelerated by using fully unstructured meshes composed of both isotropic and anisotropic tetrahedral elements. The anisotropic tetrahedral elements were used in the flow domain near the blade and shaft, where the viscous effect is important, having complex shape yet resolving the thin boundary layers. For other regions, isotropic tetrahedral elements are utilized. Two different approaches simulating rotational effect of the propeller are employed, namely Moving reference frame technique for steady simulation, and Sliding mesh technique for unsteady simulation. Both approaches are applied to the propeller open water (POW) test simulation. The current results, which are thrust and torque coefficients, are compared with available experimental data.

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.199-224
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• 1996

The value orientations and life styles which are characterized by the postmodern societies have been expanding in korean society. This paper concerns with the postmodernism for in fashion design : at first the complex relationships between the logic of post-industrial society and the culture dynamics of postmodernism will be explained. Then the characteristics of postmodernism in the comparision with the Bauhaus, also "modernism" in design areas will be critically identified, and significant examples which I select in order to criticize the basic elements or orientations of postmodern design will be analized in details.I will make a new perspective which is beyond Bauhaus and postmodernism ; namly 'open dialogism design.'. But in the boundary of its introduction.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.4
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• pp.629-638
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• 2002

This paper deals with the free vibration analysis of compressive tapered members resting on elastic foundation using the Differential Quadrature Method. Based on the differential equation subjected to the boundary conditions, adopted from the open literature, which governs the free vibrations of such member, this equation is applied to the Differential Quadrature Method. For computing natural frequencies, the numerical procedures are developed by QR Algorithm, in which the Chebyshev-Gauss-Lobatto method is used for choosing the grid points. The numerical methods developed herein for computing natural frequencies are programmed in FORTRAN code, and all solutions obtained in this study are quite agreed with those in the open literature.

• Journal of the Korean housing association
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• v.18 no.6
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• pp.103-113
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• 2007

In Korea, open spaces of urban housing do not serve residents as "regular living areas". We carried out research on the "streets" of urban housings in that the meaning of traditional "streets", playing roles which are not only means of passage but also boundary of life, cannot include present meaning of "streets" of the urban housing. This research is to propose the direction of planning Community Streets for the recovery of the public- and communal urban housing's streets, researching the present employment condition of Community Streets that were prepared recently. Working with 3 complexes which have been completed since 2000, We studied the present employment condition and planned signification, according to the conditions of their surroundings, the physical conditions of Community Streets, and the relationship among main apartment buildings, open spaces, and facilities. From this study, We came up with several suggestions that can present the planning line of Community Streets. Therefore this research is to create the Community Streets for the activity of the streets, the recovery of the community, and improvement of ambulatory environment.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.2
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• pp.57-64
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• 2004

Nowadays the parks in Shanghai tend to develop towards two directions. Small and medimn parks are being gradually transformed from closed management to open management, while large ones emphasize their nature of theme and nature of functions. Simultaneously, the number of large and open public green spaces has been significantly increased. Although the public green space does not adopt the management pattern for parks, there is almost no difference between public green space and ordinary parks so far as the functions and scales are concerned. Due to the fact that there is no obvious boundary between a public park and a public green space, this paper raises a suggestion to coordinate continuously their management and functions so that the distribution of and the connection between the urban green spaces can be more rational and more definite and a sound green network can be formed. Starting from the viewpoint of emphasizing accessibility to green spaces and enhancing the angle of linking green spaces, we aim at transforming a park system to a multifunctional green system, extending the effects and service radius of large green spaces, and strengthening the internal connections with the surrounding areas so that a high-quality green space can be formed with the connection of the green space network.

• Wind and Structures
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• v.17 no.3
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• pp.245-262
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• 2013

The flow interaction between two identical neighboring twin square prisms in a staggered arrangement in an open terrain was investigated experimentally. The downwind prism was mounted on a rigid-aeroelastic setup in an open-terrain boundary layer flow to measure its acrosswind root-mean-square responses and aerodynamic damping ratios. By varying the relative location of the upwind prism and the Scruton number associated with the downwind prism, the acrosswind aeroelastic behavior of the downwind prism was analyzed and compared to that of an isolated one. Results showed that the acrosswind root-mean-square response of the downwind prism could be either suppressed or enhanced by the wake flow produced by the neighboring upwind prism. Besides the assessment of the wake effect of the downwind prism, finally, regressed relationships were presented to describe the variation of the aerodynamic damping ratio so as to predict its acrosswind fluctuating response numerically.

• International Journal of High-Rise Buildings
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• v.11 no.4
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• pp.287-300
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• 2022

Unconventional structures are getting more popular in recent days. Large-span roofs are used for many structures, such as airports, stadiums, and conventional halls. Identifying the pressure distribution and wind load acting on those structures is essential. This paper offers a collaborative study of computational fluid dynamics (CFD) simulations and wind tunnel tests for assessing wind pressure distribution for a building with a combined slender curved roof. The hybrid turbulence model, Improved Delayed Detached Eddy Simulation (IDDES), simulates the open terrain turbulent flow field. The wind-induced local pressure coefficients on complex roof structures and the turbulent flow field around the structure were thus calculated based upon open terrain wind flow simulated with the FLUENT software. Local pressure measurements were investigated in a boundary layer wind tunnel simultaneous to the simulation to determine the pressure coefficient distributions. The results predicted by CFD were found to be consistent with the wind tunnel test results. The comparative study validated that the recommended IDDES model and the vortex method associated with CFD simulation are suitable tools for structural engineers to evaluate wind effects on long-span complex roofs and plan irregular buildings during the design stage.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.14-21
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• 2023

Recent information and communication technologies have already opened up new prospects for technology groups, especially in a knowledge-based society. A contemporary technological era, which can be stated as the hyper-connective Internet of Things surpassed the traditional service pattern and innovation pattern by conveying personalized, localized, and con-text-aware services close to different actors and users. The conventional boundary of the organization is disbanding as well as traditional innovation and research & development limits. This research article conducts a preliminary study about the hyper-connective Internet of Things technology portent with innovation 3.0 version based on an extended technological organization environment framework (E-TOEF). This article discusses the emergence of innovation 3.0 as a paradigm shift from a manufacturing paradigm to an actor-oriented paradigm. There is a need to shift from a manufacturing mindset to more user ergonomics and be aware of the potential of hyper-connective IoT on the revolution of innovation patterns to be more cooperative, open, and user-centered. Besides, this article would strain some conceptual approaches for the next-generation innovation paradigm known as "hyper-connective IoT" entitled innovation 3.0. This new innovation version goes beyond open innovation and undeniably clearly beyond closed innovation which was an earlier version.