• Journal of Korea Multimedia Society
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• v.10 no.7
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• pp.902-911
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• 2007

GSM platform is a hugely successful wireless technology and an unprecedented story of global achievement. In less than ten years since the first GSM network was commercially launched, it became the world's leading and fastest growing mobile standard, using over 1 billion GSM subscribers across more than 200 countries of the world. GSM platform evolved into 3th generation mobile communication which includes not only voice call services but also the international roaming and various kinds of the multimedia services. GSM is an essential element techniques a safe data transmission and a personal private protection while support services. However, a crypto algorithm and a secure protocol for a safe data communication using GSM are indicating various kinds of problems. In this paper, we propose a more safer and more efficient authentication protocol in 3th generation network through analysis of GSM security mechanism of 2th/2.5th generation. This security protocol offers enforced security efficiency by using user verification between SIM/ME and reduction of authentication and key agreement step between SIM/ME/AuC.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.915-920
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• 2009

In terms of development of intelligent information devices, the most important element is the function which is able to deliver the information user wants to input on the device without complexities. By using the mean such as our voice, expression, gesture and physical contact we use in our daily routine, we are able to interact with device easily and simply. In this paper, we are initiated to present interactive surface system, in which allows users to use their hand gesture as a function of mouse and keyboard free, to be interacted within the platform of web application.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.2985-2995
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• 1997

In this paper, we proposed the "synchronous & asynchronous distance education system" which is able to interact among teachers and students for open education in cyberspace, and it is based telecommunication technology and multimedia technology. Specially, This system gets rid of the nufamiliarity and inconvenient feeling during the distance education. Also it supports the mediation of floor mode, for a group lecture and supports the synchronous mode for face-to-face effective and asynchronous mode for self-learning. The asynchronous mode has the down load function and the consultant mode (between teacher and student). The element technologies of this system consists of application sharing technique, whiteboard, various video window display, audio support, user interface, environment setup, session management, access control, network control and media control for collaborative distance education.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.9A
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• pp.694-701
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• 2003

In this paper, we present a hardware structure and new features of a smart antenna BTS (Base Transceiver Station) for CDMA2000 1X system. The proposed smart antenna BTS is a composite system consisting of many subsystems, i.e., array antenna element, frequency up/down converters, AD (Analog-to-Digital) and DA (Digital-to-Analog) converters, spreading/despreading units, convolutional encoder/Viterbi decoder, searcher, tracker, beamformer, calibration unit etc. Through the experimental tests, we found that the desired beam-pattern in both uplink and downlink communications is provided through the calibration procedure. Also it has been confirmed that the adaptive beamforming algorithm adopted to our smart antenna BTS is fast and accurate enough to support 4 fingers to each user. In our experiments, commercial mobile terminals operating PCS (Personal Communication System) band have been used. It has been confirmed that the smart antenna BTS tremendously improves the FER (Frame Error Rate) performance compared to the conventional 2-antenna diversity system.

• Journal of IKEEE
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• v.23 no.4
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• pp.1343-1352
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• 2019

To manage the Internet of Things(IoT) Network, which consists of a large number of various devices, a secure and automatic method of strengthening the IoT network is being proposed. Blockchain has a 'smart contract' element of autonomous execution method, which is emerging as a way to not only exchange data quickly without mediators but also securely and automatically manage processes between IoT devices. In this paper, we implement a prototype of the entire IoT device management system based on the EOSIO with DPoS(Distributed Proof of Stake)-based blockchain structure, proposed as a prior study, including the user application DApp(Decentralized Application) and the actual IoT devices (Raspberry Pi-based device, and smart lamp) that interact with the blockchain platform. We analyze the benefits of the system and measure the time overhead to show the feasibility of the system.

• Journal of Korean Society for Geospatial Information Science
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• v.13 no.4 s.34
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• pp.39-46
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• 2005

This paper use virtual running after possible traffic capacity application for optimal route location. General road is designed the design after we examine an alternate adequacy investigation and an execution design sufficiently. Various road user's requirement must be reflected from the beginning. But it is difficult to contain the various suitable design criteria because we consider the existing 2-dimension element. First of all, this study chose optimal route, used traffic assignment and 3D simulation. Then selected optimal route through the consistent road construction by analyzing road driving simulation of 3-dimension data and the urban landscape. possible traffic capacity and virtual running will be able to do the urban landscape analysis harmonizing with the environment; equally, it could be objectively solve the problem of a civil appeal.

• Journal of the Korean Society for Library and Information Science
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• v.44 no.4
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• pp.33-59
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• 2010

Library 2.0 advocates a socially rich, multimedia enabled, user originated and communally innovative environment that poses significant opportunities for the libraries to evolve and make themselves even more relevant and significant for her users. This paper presents a case study of the National Library Board of Singapore, in playing a vital role to facilitate the realisation of a long-term key national program, The Singapore Memory (SM) Project. SM embraces the attributes of the Library 2.0 environment to enable the nation's memory to be collected, organised, preserved, discovered, researched, augmented and created. The output of is an evolving collection of knowledge assets on Singapore along a Singapore Memory Content Continuum of existing content that is steadily augmented with new content. The content will be collected across all formats, in any language, from Singaporeans and non-Singaporeans, from any institution and agency, from Singapore and abroad, and from official and unofficial sources. The utopian scenario of SM Project is that any person, community, group or institution who has ever experienced Singapore in any way or has any material on Singapore will engage actively in the contribution, discovery and creation of content for the project, and thus become advocates to further encourage and catalyse more contribution, discovery and creation. The paper outlines the key approaches, concepts and ideas for the project. An important element is the proliferation, exposure and accessibility of the rich contents envisaged in the project. The SM proliferation plan along with examples of how two existing resources, namely, the Singapore Infopedia, a database of articles on Singapore's history, culture, people and events 4 and NewspaperSG, an online resource of current and historic Singapore and Malayan newspapers, have been designed are presented to demonstrate how content can be exposed, searched and discovered.

• Smart Structures and Systems
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• v.14 no.1
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• pp.39-54
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• 2014

Node layout optimization of structural wireless systems is investigated as a means to prolong the network lifetime without, if possible, compromising information quality of the measurement data. The trade-off between these antagonistic objectives is studied within a multi-objective layout optimization framework. A Genetic Algorithm is adopted to obtain a set of Pareto-optimal solutions from which the end user can select the final layout. The information quality of the measurement data collected from a heterogeneous WSN is quantified from the placement quality indicators of strain and acceleration sensors. The network lifetime or equivalently the network energy consumption is estimated through WSN simulation that provides realistic results by capturing the dynamics of the wireless communication protocols. A layout optimization study of a monitoring system on the Great Belt Bridge is conducted to evaluate the proposed approach. The placement quality of strain gauges and accelerometers is obtained as a ratio of the Modal Clarity Index and Mode Shape Expansion values that are computed from a Finite Element model of the monitored bridge. To estimate the energy consumption of the WSN platform in a realistic scenario, we use a discrete-event simulator with stochastic communication models. Finally, we compare the optimization results with those obtained in a previous work where the network energy consumption is obtained via deterministic communication models.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.269-274
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• 2008

For fitness-for-service analyses of underground natural gas pipelines, engineering assessment methods against possible defects need to be developed. The assessment methods for high pressure pipeline of KOGAS, was developed using the full size pipe burst tests and the finite element analysis. It included the defect assessment methods for a single and multi-corrosion, corrosion in girth welding part, corrosion in seam welding part, the mechanical damage defects as dent and gouge, crack and large plastic deformation of API 5L X65 pipe. In addition, we developed method to assess pipeline integrity by internal and external load to buried pipeline. Evaluation results were compared with other methods currently being applied to the gas pipeline. The program of Windows environment is made for easily using assessment methods. It provides a consistent user interface, so non-professional technician can easily and friendly use the FFS program from company intranet. Several evaluation programs is easily installed using one installer. Each program constitutes a common input interface and the output configuration program, and evaluation result store and can be recalled at any time. The FFS program based on independent evaluation method is used to evaluate the integrity and safety of KOGAS pipeline, and greatly contribute to safe and efficient operation of pipeline. This paper presents experimental, analytical and numerical investigations to develop the FFS methods for KOGAS pipeline, used as high pressure natural gas transmission pipeline within KOREA. Also, it includes the description of the integrated program for FFS methods.

• Structural Engineering and Mechanics
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• v.72 no.6
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• pp.713-722
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• 2019

Micromechanics is a technique for the analysis of composites or heterogeneous materials which focuses on the components of the intended structure. Each one of the components can exhibit isotropic behavior, but the microstructure characteristics of the heterogeneous material result in the anisotropic behavior of the structure. In this research, the general mechanical properties of a 3D anisotropic and heterogeneous Representative Volume Element (RVE), have been determined by applying periodic boundary conditions (PBCs), using the Asymptotic Homogenization Theory (AHT) and strain energy. In order to use the homogenization theory and apply the periodic boundary conditions, the ABAQUS scripting interface (ASI) has been used along with the Python programming language. The results have been compared with those of the Homogeneous Boundary Conditions method, which leads to an overestimation of the effective mechanical properties. According to the results, applying homogenous boundary conditions results in a 33% and 13% increase in the shear moduli G₂₃ and G₁₂, respectively. In polymeric composites, the fibers have linear and brittle behavior, while the resin exhibits a non-linear behavior. Therefore, the nonlinear effects of resin on the mechanical properties of the composite material is studied using a user-defined subroutine in Fortran (USDFLD). The non-linear shear stress-strain behavior of unidirectional composite laminates has been obtained. Results indicate that at arbitrary constant stress as 80 MPa in-plane shear modulus, G₁₂, experienced a 47%, 41% and 31% reduction at the fiber volume fraction of 30%, 50% and 70%, compared to the linear assumption. The results of this study are in good agreement with the analytical and experimental results available in the literature.