• Tunnel and Underground Space
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• v.9 no.2
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• pp.131-140
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• 1999

Although there have been lots of geological or geotechnical surveys for construction sites, most of data obtained from these surveys have not been reused properly for the future construction work due to the absence of systematic management of data management system. This research, therefore, has focused on the development of DB system, Rockmass Information Management System(RIMS), to save, manage and reuse these abandoned data, specially test data of rock and rockmass with site conditions. RIMS has not only the basic functions of inputting, modifying, and dynamic searching of data but also several data control modules which can manage, input and correct, analyse and report data. Furthermore it saves data such as strata status, laboratory test results, in-site test results, and so on using 3-dimensional data stacking up structure. It is using x, y coordinates to represent horizontal positions and depth to represent vertical position of data. With the development of RIMS, this research has analyzed and classified present conditions of data in RIMS according to region, rock type, etc.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.183-188
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• 2008

Engine control/performance model for helicopter simulator is one of the most important models which affect flight performance and handling quality. It is typical to develop the model based on the raw data and models from the engine designers/manufacturers. The approaches in this study were to develop the basic model based on the available resources and to tune and verify it based on the ground/flight test results. The maintenance manuals of TB3-117 which is installed in KA-32T were reviewed and the components to be simulated for the engine control model were categorized and modeled. Piece-wise linear modeling method was used for the engine performance model. The engine performance data in the engine maintenance manuals were incorporated into the engine steady state performance tables, which were incorporated with the transfer functions for the dynamic performance. Engine control/performance model was compared and tuned with the ground/flight test results. It was verified that the fidelity of the model was within the tolerances in FAA AC120-63.

• Composites Research
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• v.28 no.2
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• pp.58-64
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• 2015

The purpose of this paper is to suggest the effective equivalent finite element model for the impact limiter of a nuclear spent fuel shipping cask made of sandwich composite panels. The sandwich composite panels were composed of a metallic facesheet and a core material made of urethane foam, balsa wood and red wood, respectively. The effective equivalent finite element model for the impact limiter was proposed by comparing the results of low-velocity impact test of sandwich panels. An explicit finite element analysis based on LS-DYNA 3D was done in this study. The results showed that the solid elements were recommended to model the facesheet and core of sandwich panels for impact limiter compared to combination modeling method, in which the layered shell element for facesheet and solid element for core material are used. In particular, the solid element for balsa and red wood core materials should be modeled by the element elimination approach.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2239-2246
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• 2008

Engine control/performance model for helicopter simulator if one of the most important models which affect flight performance and handling quality. It is typical to develop the model based on the raw data and models from the engine designers/manufacturers. The approaches in this study were to develop the basic model bated on the available resources and to tune and verify it based on the ground/flight test results. The maintenance manuals of TB3-117 which is installed in KA-327 were reviewed and the components to be simulated for the engine control model were categorized and modeled. Piece-wise linear modeling method was used for the engine performance model. The engine performance data in the engine maintenance manuals were incorporated into the engine steady state performance tablet, which were incorporated with the transfer functions for the dynamic performance. Engine control/performance model was compared and tuned with the round/flight test results. It was verified that the fidelity of the model was within the tolerances in FAA AC120-63.

• Journal of Broadcast Engineering
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• v.20 no.2
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• pp.283-299
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• 2015

In this paper, we propose new broadcasting services that combine MMT (MPEG Media Transport) standard with MPEG-DASH (Dynamic Adaptive Streaming over HTTP) standard. MMT is a next-generation multimedia transport standard that is IP-friendly and provides functionalities appropriate for hybrid broadcasting that uses broadcast physical channels and the Internet simultaneously. MPEG-DASH enables media streaming services that can be dynamically adaptive both to the network traffic conditions of wired and/or wireless Internet and the receiving entity environment. We explain the scenarios of the proposed broadcasting services and demonstrate that various hybrid broadcasting services can be easily realized through the combined usage of MMT and MPEG-DASH. By making the test bitstreams containing contents for the new services and developing the receiver back-end software that performs the function of the receiving entity for the new services on personal computers, we verified that the proposed scenarios can be realized.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.5
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• pp.578-587
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• 2003

The DSTM (Dual Stack Transition Mechanism), one of tunneling mechanism, is considered as the best solution in IPv4/IPv6 transition recently. The DSTM provides a method to assure IPv4/v6 connectivity based on 4over6 (IPv4-over-IPv6) tunneling and temporal allocation of a global IPv4 address to a host requiring such communication. A TEP (Tunnel End Point) operates as a border router between IPv6 domain and IPv4 Internet, which performs encapsulation and decapsulation of 4over6 tunneling packets to assure hi-directional forwarding between both networks. In this paper, we analyze basic standards of the IPv6 protocol. And, we design and implement a DSTM TEP daemon block. The TEP daemon analyzes a fevers tunneling packet that is forwarded by the DSTM node, establishes the TEP's 4over6 interface, and supplies communication between a DSTM and a IPv4-only node. Finally, we construct a DSTM testbed and measure performance of the DSTM TEP. Our observation results show that performance of TEP supports the DSTM service.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.7
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• pp.797-803
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• 2012

Proportional solenoid valves are a modulating type that can control the displacement of valves continuously by means of electromagnetic forces proportional to the solenoid coil current. Because the solenoid-type modulating valves have the advantages of fast response and compact design over air-operated or motor-operated valves, they have been gaining acceptance in chemical and power plants to control the flow of fluids such as water, steam, and gas. This paper deals with the auto tuning of the position controller that can provide the proportional and integral gain automatically based on the dynamic system identification. The process characteristics of the solenoid valve are estimated with critical gain and critical period at a stability limit based on implemented relay feedback, and the controller parameters are determined by the classical Ziegler-Nichols design method. The auto-tuning algorithm was verified with experiments, and the effects of the operating point at which the relay control is activated as well as the relay amplitude were investigated.

• The KIPS Transactions:PartA
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• v.9A no.1
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• pp.1-8
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• 2002

Most of the traditional embedded web server systems have been designed for monitoring and controlling some dedicated equipments. Hence, not only they have no generality and flexibility but also they are too expensive for the lower-cost domestic equipment. To cope with these difficulty, we suggest a lower-cost ${\mu}$-embedded web server model which is suitable for monitoring and controlling the industry or house equipments by using the internet. The suggested model is based on an one-chip ${\mu}$-processor in which the ISP (In-System Programming) function and flash ROM are embedded basically to minimize the cost of H/W and S/W. Also it allows to add an new function dynamically to provide the generality and flexibility. Finally, to evaluate the feasibility of the suggested model, we have manufactured a test-board based on the ATMega103 ${\mu}$-processor and programmed the control program and tested it on the MS Explorer 5.0 environment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.9-16
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• 2014

In recent years, the structural shock response to UNDEX (UNDerwater EXplosion) has been studied as much, or more, through numerical simulations than through testing for several reasons. Very high costs and sensitive environmental concerns have kept destructive underwater explosion testing to a minimum. Increase of simulation capabilities and sophisticated simulation tools has made numerical simulations more efficient analysis methods as well as more reliable testing aids. In this study, the main issue is the fluid-structure interaction. Here, appropriate relations between the acoustic pressure on the fluid surface and displacements on the structure surface are formed internally. The analysis was carried out using ABAQUS/Explicit and the results have been visualized in ABAQUS CAE. The shock loading history, acoustic pressure, stress of stand-off point, the velocity and strain energy time histories were presented.

• The KIPS Transactions:PartC
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• v.12C no.5 s.101
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• pp.679-686
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• 2005

Because EPON access network shares a medium and aggregates the traffic from EPON subscribers, scheduling media access control on EPON bandwidth allocation is very important. Furthermore DBA mechanism of EPON based on TDMA is out of specification and up to implementation. This paper deals with a DBA method to guarantee the QoS of the delay sensitive traffic on the base of best-effort service and delay priority queue management. The proposed method performs virtual scheduling algorithm for the integrated traffic. It uses the same MAC messages and tries to guarantee the QoS of higher priority traffic first with a simple DBA architecture. We evaluate the algorithm for traffic delay according to polling interval and traffic load of upstream and downstream. The results show that the proposed method can guarantee the QoS of the delay sensitive traffic with priority of the service classes.