• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.85-91
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• 1998

Many of the newest network suers are gaining their fist network experience as users of the Internet. Because of the universal nature of this exciting new experience, millions of new users are driving the demand for increasingly multimedia oriented applications, especially in communication area. Since the communication via the Internet can use various media forms including audio, video and graphics, it can e very efficient communication system on the Internet, which allows Internet users to communicate, collaborate, and associate with others. Webber provides various communication services, like ACS(Audio Conference System), VCS(Video Conference System) and Virtual Space, in an integrated environment. Webber consists of Service-PUBs(Processing Unit Plug-in), which process each service, and Framework, which manages these PUPs. PUP is so highly independent of each other that it's easy to add, maintain, delete services and also optimally configure the system to user's terminal performance or network status.

• ETRI Journal
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• v.38 no.6
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• pp.1085-1094
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• 2016

In this work, we present interactive automultiscopic content with mobile surface haptics for multimodal interaction. Our system consists of a 40-view automultiscopic display and a tablet supporting surface haptics in an immersive room. Animated graphics are projected onto the walls of the room. The 40-view automultiscopic display is placed at the center of the front wall. The haptic tablet is installed at the mobile station to enable the user to interact with the tablet. The 40-view real-time rendering and multiplexing technology is applied by establishing virtual cameras in the convergence layout. Surface haptics rendering is synchronized with three-dimensional (3D) objects on the display for real-time haptic interaction. We conduct an experiment to evaluate user experiences of the proposed system. The results demonstrate that the system's multimodal interaction provides positive user experiences of immersion, control, user interface intuitiveness, and 3D effects.

• Computers and Concrete
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• v.9 no.4
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• pp.293-310
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• 2012

This paper discusses a new constitutive model called the high-rate brittle microplane (HRBM) model and also presents the details of a new software package called the Virtual Materials Laboratory (VML). The VML software package was developed to address the challenges of fitting complex material models such as the HRBM model to material property test data and to study the behavior of those models under a wide variety of stress- and strain-paths. VML employs Continuous Evolutionary Algorithms (CEA) in conjunction with gradient search methods to create automatic fitting algorithms to determine constitutive model parameters. The VML code is used to fit the new HRBM model to a well-characterized conventional strength concrete called WES5000. Finally, the ability of the new HRBM model to provide high-fidelity simulations of material property experiments is demonstrated by comparing HRBM simulations to laboratory material property data.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.3
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• pp.28-33
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• 2002

Several studies indicated that an independent visual background (IVB) reduced simulator sickness (SS) and balance disturbance associated with exposure to virtual environments (VEs) and motion simulators. A recent study showed that an IVB comprised of an earth-fixed grid was less effective in a complex driving simulator than in a simple VE. Subjects' post-experiment reports indicated that the VE motion "induced" motion of the earth-fixed grid m. This led to the suggestion that an IVB comprised of clouds would be less subject to induced motion and therefore would alleviate nausea more effectively than a grid IVB. Clouds are "natural" and are usually perceived as relatively stable, whereas a grid has no inherent stability. 12 subjects were exposed to complex motion through a simulated environment in a driving simulator under 3 IVB conditions: grid, less clouds, many clouds. They reported less nausea when the many-cloud IVB was used relative to the grid IVB condition. grid IVB condition.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2603-2605
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• 2001

In this paper, we introduce the concept and construction of a web-based bidirectional remote laboratory system. In this configuration, students build and test circuits using internet at home, and the circuit components and experimental equipments at the school are interconnected following student's design. This means that it is possible to choose components, build circuits, connect experiment equipments, control the equipment. and receive measurement results at home in real-time. Labview and Java are used to control this system efficiently and to provide user-friendly environments. Computer-based function generator, DMM, and oscilloscope are used and switch module is used to change interconnections. It was found that a system adopting computer-based instruments, which include PXI/CompactPCI modules and PC plug-in board, provide better performance than that adopting stand-alone instruments connected with GPIB. It is believed that, if this system is installed, the real experiments, not the virtual experiments based on simulation, can be done at home effectively, resulting in revolutional change in engineering education.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.1123-1128
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• 2000

현재 사용되는 전자 지불 시스템은 전자 상거래의 기본 요소인 기밀성, 인증, 메시지 무결성, 부인 방지, 재사용 방지 등을 위하여 공개키 방식의 연산을 수행한다. 그러나, 이러한 공개키 방식은 많은 시스템 연산 수행을 요구한다는 단점이 있다. 이에 본 논문에서는 현재 네트웍 보안에 많이 사용되고 있는 VPN( Virtual Private Network )을 이용하여 대칭키 기반의 전자 지불 시스템을 설계함으로써 좀 더 안전하고 효율적인 전자 지불을 수행하고자 하였다.

• Structural Engineering and Mechanics
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• v.68 no.6
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• pp.661-675
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• 2018

In this paper, buckling analysis of hybrid functionally graded plates using a novel four variable refined plate theory is presented. In this theory the distribution of transverse shear deformation is parabolic across the thickness of the plate by satisfying the surface conditions. Therefore, it is unnecessary to use a shear correction factor. The variations of properties of the plate through the thickness are according to a symmetric sigmoid law (symmetric S-FGM). The principle virtual works is used herein to extract equilibrium equations. The analytical solution is determined using the Navier method for a simply supported rectangular plate subjected to axial forces. The precision of this theory is verified by comparing it with the various solutions available in the literature.

• International Journal of Computer Science & Network Security
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• v.21 no.1
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• pp.64-69
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• 2021

In this paper, we have proposed a new internal model control structure (IMC). It is aimed at unstable overactuated multivariable systems whose transfer matrices are singular and unstable. The model inversion problem is essential to understand this structure. Indeed, the precision between the output of the process and the setpoint is linked to the quality of the inversion. This property is preserved in the presence of an additive disturbance at the output. This inversion approach proposed in this article can be applied to multivariable systems with no minimum phase or minimum phase shift with or without delays in their transfer matrices. It is proven by an example of simulation through which we have shown its good performance as a guarantee of stability, precision as well as rapidity of system responses despite the presence of external disturbances and we have tested this control structure in the frequency domain hence the robustness of the IMC.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1986.04a
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• pp.119-124
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• 1986

This paper describes the development of the KORNET that may be regarded as the latest public packet-swiched computer communication network. The KORNET project included the development of the network management center (NMC), a network concentrator. For the KORNET we use the virtual circuit(VC) method, a distributed adaptive routing algorithm, and a dynamic buffer management algorithm. The NMC acts as a nerve center of the network, performing such function as network monitoring, subscriber and network management and routing management, etc. As for the NNP and NC hardware, we have implemented them with the 16-bit multitask/multiprocessor technology using MC68000 microprocessors. Softwares have been developed using C language is required for real time processing. All the network protocols we have developed comply completely with the latest CCITT recommendations including X.25, X,3 , X.28 and X.29.

• Computers and Concrete
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• v.26 no.2
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• pp.185-201
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• 2020

This research is devoted to investigate the bending and free vibration behaviour of laminated composite/sandwich plates and shells, by applying an analytical model based on a generalized and simple refined higher-order shear deformation theory (RHSDT) with four independent unknown variables. The kinematics of the proposed theoretical model is defined by an undetermined integral component and uses the hyperbolic shape function to include the effects of the transverse shear stresses through the plate/shell thickness; hence a shear correction factor is not required. The governing differential equations and associated boundary conditions are derived by employing the principle of virtual work and solved via Navier-type analytical procedure. To verify the validity and applicability of the present refined theory, some numerical results related to displacements, stresses and fundamental frequencies of simply supported laminated composite/sandwich plates and shells are presented and compared with those obtained by other shear deformation models considered in this paper. From the analysis, it can be concluded that the kinematics based on the undetermined integral component is very efficient, and its use leads to reach higher accuracy than conventional models in the study of laminated plates and shells.