• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.6
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• pp.140-146
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• 2011

As the demand of Variable Message Sign(VMS) has become pervasive in fulfilling the ITS policy, the costs of maintaining the Variable Message Sign operation have also increased. This paper proposes the U-curved figure, the C-curved figure and the ventilated figure type for aerodynamic drag reduction on Variable Message Sign and shows the analysis of aerodynamic drag effects using Flow Analysis. As a results of the flow analysis for right-angled, 45 degrees from side to side and 45 degrees from up or down, the C-curved figure and the ventilated figure type show about 30% aerodynamic drag reduction in all direction. And the U-curved figure type shows vivid aerodynamic drag reduction for right-angled and 45 degree from side to side, but trivial aerodynamic drag reduction for 45 degree from up or down. It is possible to reduce not only the damage on Variable Message Sign due to typhoon because of the aerodynamic drag reduction, but also installation constraints because of lighter Variable Message Sign support structure by appling the proposed structure and analysis in this paper.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.351-355
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• 2009

There are two types of controller between railway and train. those are the Continuous Message Controller and the Intermittent Message Controller using for KHSR. The conventional Intermittent Message Controller board used a variable resister for setting the phase, but the variable resister affected some environmental facts, such as temperature, humidity, and vibration, etc. And It is requirement of reduction message processing time for speed-up operation in Next-Generation High-Speed Rail. This study suggests how to solve the problem described above. Using FPGA is quite profitable. It's easy to use and maintain, flexible with the New algorithm to fix up the problem.

• Journal of Information Processing Systems
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• v.4 no.4
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• pp.133-144
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• 2008

Clusters have become a popular alternative for building high-performance parallel computing systems. Today's high-performance system area network (SAN) protocols such as VIA and IBA significantly reduce user-to-user communication latency by implementing protocol stacks outside of operating system kernel. However, emerging parallel applications require a significant improvement in communication latency. Since the time required for transferring data between host memory and network interface (NI) make up a large portion of overall communication latency, the reduction of data transfer time is crucial for achieving low-latency communication. In this paper, Eager Data Transfer (EDT) mechanism is proposed to reduce the time for data transfers between the host and network interface. The EDT employs cache coherence interface hardware to directly transfer data between the host and NI. An EDT-based network interface was modeled and simulated on the Linux-based, complete system simulation environment, Linux/SimOS. Our simulation results show that the EDT approach significantly reduces the data transfer time compared to DMA-based approaches. The EDTbased NI attains 17% to 38% reduction in user-to-user message time compared to the cache-coherent DMA-based NIs for a range of message sizes (64 bytes${\sim}$4 Kbytes) in a SAN environment.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.3 no.1
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• pp.15-24
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• 2004

'The delay and control overhead during route discovery for destinations outside ad hoc networks are major obstacle to achieving scalability in the Internet. To solve this issue, we propose a novel route discovery scheme equipped with two augmented functions. In this paper, the Internet gateway maintains an address cache of Internet nodes frequently accessed from the ad hoc network and replies with an extended Route Response (RREP) message to the Route Request (RREQ) message based on its routing table and the address cache called EXIT(EXternal node Information Table). These augmented functions make the source node determine the location of the destination as fast as possible. Through simulations, the proposed route discovery scheme using both EXIT and extended RREP message shows considerable' reduction in both route discovery time and control message overhead.

• Journal of Energy Engineering
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• v.21 no.1
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• pp.33-42
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• 2012

In this study, long-term greenhouse gas reductions expected passenger sector was used for the MESSAGE. Green Car road map proposed BAU scenario, Enhanced diffusion green car scenario, and price 1, 2 scenarios was configured with four scenarios. Enhanced diffusion green car in the scenario, in 2050 compared to BAU scenario 13% of the emissions will decrease. Price 1 and Price 2 scenario is emissions reduction of 14% compared to BAU. This study consists of six chapters. Introduction of MESSAGE, creation and RES in the year and the target year set a different base line and the passenger building materials sector activities, steps for passenger sector scenario and Based on the results of running the emissions reductions were to describe.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.1
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• pp.47-54
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• 2004

The friction drag reduction of a ship is of prime importance for the design and production of high-valued/high-tech ship. Thus, this study carried out the development of reliable numerical tools to identify the friction drag reduction mechanism for turbulent boundary layer on the ship surface and to deduce the optimum reduction technique by numerical experiment. The developed LES and DNS numerical tools were applied to simulate the turbulent channel flow These results were very well matched with previous results not only qualitatively but also quantitatively. The parallelization using MPI (Message Passing Interface) technique implemented in the developed code to speed up the simulation and to obtain the accurate results from the fine grid system was testified its computational efficiency.

• Journal of the Korea Society for Simulation
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• v.8 no.1
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• pp.77-88
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• 1999

There are two approaches to handle the Causality Error in parallel and distributed simulation. One approach is based on the conservative time synchronization and the other is the optimistic time synchronization. In this paper an efficient null message reduction method for the conservative time synchronization approach is suggested with the experimental results, which could improve performance of simulation and avoid deadlock situations.

• KIISE Transactions on Computing Practices
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• v.23 no.12
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• pp.670-676
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• 2017

Naval combat systems use real-time processing and compositing of collected information to provide the optimal combat capabilities that maximize survival and ensure mission effectiveness. The software for a combat system has dozens to thousands of components depending on the size of the system, and the communication between the components is achieved via DDS. Although the message interface of the combat system is managed through MDMS, an increase in the system size can result in problems such as the deterioration of the development efficiency. In this paper, we implement XMDMS to operate a distributed processing environment and then solve the problem of the reduction in the development efficiency caused by a load at the server. The experimental results shows that XMDMS improves the processing delay and network performance compared to MDMS.

• Journal of Korean Society of Transportation
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• v.17 no.1
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• pp.91-102
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• 1999

The objective of this study is to evaluate traffic management strategies using Variable Message Signs(MCS) on urban freeways. It is well known that real-time information on traffic conditions increases driver's comfort, and reduces the risks of accidents if drivers are aware of the traffic situation in advance, they decide whether to divert from the freeway or continue on the planned route. The experimental data collected on the Olympic highway we have shown the following results : 1. when the information on both the congested freeway and uncontested diversion route is displayed on the variable message sign. an additional 1.7 percent of traffic diverted, which results in a 3.7 percent reduction in total travel time. 2 Compared with one Proposed VMS message of 'reduce the speed', the other Proposed VMS message of 'keep speed 70km/h' is found to be much more effective in reducing mean speed.

• Journal of Korea Society of Industrial Information Systems
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• v.8 no.4
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• pp.26-30
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• 2003

The Lanczos algorithm is the most commonly used in approximating a small number of extreme eigenvalues for symmetric large sparse matrices. Global communications in MP(Message Passing) parallel computer decrease the computation speed. In this paper, we introduce the s-step Lanczos method, and s-step method generates reduction matrices which are similar to reduction matrices generated by the standard Lanczos method. One iteration of the s-step Lanczos algorithm corresponds to s iterations of the standard Lanczos algorithm. The s-step method has the minimized global communication and has the superior parallel properties to the standard method. These algorithms are implemented on Cray T3E and performance results are presented.