• Journal of the Institute of Electronics Engineers of Korea CI
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• v.37 no.4
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• pp.1-8
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• 2000

The massive growth of the internet and the world-wide-web leads us to research the programming languages for the development of applications in heterogeneous, network-wide distributed environments. Java is an object-oriented language for such a environment and the Java programming language environment provides a portable, interpreted, high-performance, simple programming language. Bytecode is an intermediate code for Java language and it enables the development of applications on multiple platform in heterogeneous, distributed networks. But it takes much time to execute Bytecode because of using an interpretation method. In this paper, we design and implement a retargetable code generation system which can be systematically reconfigured to generate code for a variety of distinct target computers. From the system, we realize the code generation system which translates the Bytecode being produced by Java compiler into Pentium target code. We use ACK code generation system to do the work easily.

• Journal of the Korean Data and Information Science Society
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• v.26 no.5
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• pp.1155-1166
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• 2015

It is almost impossible to store or analyze big data increasing exponentially with traditional technologies, so Hadoop is a new technology to make that possible. In recent R is using as an engine for big data analysis based on distributed processing with Hadoop technology. With RHadoop that integrates R and Hadoop environment, we implemented parallel multiple regression analysis with various data sizes of actual data and simulated data. Experimental results showed our RHadoop system was faster as the number of data nodes increases. We also compared the performance of our RHadoop with lm function and biglm packages available on bigmemory. The results showed that our RHadoop was faster than other packages owing to paralleling processing with increasing the number of map tasks as the size of data increases.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.10
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• pp.1166-1172
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• 2012

In this paper, by using a commercial EM simulator, we could obtain the array manifold which are phase responses of an array antenna for the incident plane wave and then verified the effectiveness of methodology after comparing with the measurement. The result shows that the array manifold can be calculated including not only the phase response of the ideal point sources but also the influences of the mutual coupling between antennas and the installed platform. Also it can exclude the interference of strong broadcasting signal and the disturbance of the multipath in the calibration process. Finally, to predict the performances of direction finding systems, a novel method using both the EM simulation-based receiving signal and the sparsely sampled array manifold with the parabolic estimation is proposed. This method can be utilized in the various fields of direction-finding since it shows the superior predictive performance even in low SNR conditions.

• Journal of KIISE:Software and Applications
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• v.28 no.11
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• pp.842-854
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• 2001

Today\`s first generation shopping agent is limited to comparing merchant offerings usually on price instead of their full range of attributes. Even in the full range comparison, there is not a good model which considers the overall features in the negotiation process. Therefore, the negotiation model needs to be extended to include negotiations over the more attributes. In this paper, we propose a negotiation model in the agent-mediated electronic commerce to negotiate over prices, product features, warranties and service policies based on utility theory and simple heuristics. We will describe a prototype agent-mediated electronic commerce framework called Pmart. This framework provides the software reuse and the extensibility based on the object-oriented technology. It is implemented on Windows-based platforms using Java and CORBA for the network transparency and platform independence.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.10
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• pp.877-888
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• 2012

Network virtualization technology is a crucial research issue of Future Internet which pursues a service-oriented architecture so-called NaaS (Network as a Service) or SDN (Software Defined Network). Network virtualization is expected to play an important role in Future Internet researches as a network testbed technology which enables innovative protocols to be experimented independently on a common testbed environment. We propose a control framework in order to provide user defined topology and bandwidth services with network virtualization and to separate and manage multiple-user traffics in a small and medium scale - single domain research network. The proposed framework (VIMS; Virtual network Integrated control and Management System) supports testbed expansions without any changes of heterogeneous virtual network support equipments through accommodation of each equipment's control plane. The framework shows a feasibility through applied to KOREN and we describe the differences and further study directions for improvement the framework comparing with GENI control framework.

• Journal of Elementary Mathematics Education in Korea
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• v.2 no.1
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• pp.61-80
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• 1998

Whereas research on telelearning in educational technology area is lively done, that in mathematics education area is not. Related to the open education, telelearning has 4 models: the distance classroom model, the front-end system design, the knowledge construction model, and the teaching model based on data. S/W, C/W, and H/W are the components of telelearning system. For an effective mathematics telelearning system, H/W and S/W which use multimedia with complex multimode information such as text, graphics, animation, video, and audio are necessary. Examples of telelearning systems on going are MIPOS, SDS telelearning system, telelearning system of the Naechon Elementary School, and Doorae Multimedia Application Development Platform.

• Journal of the Korean GEO-environmental Society
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• v.21 no.5
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• pp.5-11
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• 2020

Outliers detection and elimination included in field monitoring datum are essential for effective foundation of unusual movement, long and short range forecast of stability and future behavior to various structures. Integrated outlier analysis system for assessing long term time series data was developed in this study. Outlier analysis could be conducted in two step of primary analysis targeted at single dataset and second multi datasets analysis using synthesis value. Integrated outlier analysis system presents basic information for evaluating stability and predicting movement of structure combined with real-time safety management platform. Field application results showed increased correlation between synthesis value including similar sort of sensor showing constant trend and each single dataset. Various monitoring data in case of showing different trend can be used to analyse outlier through correlation-weighted value.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.17-25
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• 2000

ATM PON system is regarded as a solution of the next generation access network because it can cover various types of subscribers in a single platform. In this paper, we describe the merit of the ATM PON and the key protocols for its operation. Above all, the ranging is the most important protocol providing a mean of the time-division multiple access in the system. A problem in the protocol is that the window size, the time interval that ranging cell arrives, is too long. During the interval, user traffics cannot be send to the upstream, which makes the quality of service degraded. In this paper, we suggest a method to minimize the window size when the length of the optic fiber is known with some deviation. The window size can be reduced as 7 % of the conventional method when the deviation of the length is 1 Km.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.4
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• pp.696-706
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• 2007

Multiprocessor system on chip (MPSoC) platform has set a new innovative trend for the System on Chip (SoC) design. With the rapidly approaching billion transistors era, some of the main problem in deep sub-micron technologies characterized by gate lengths in the range of 60-90 nm will arise from non scalable wire delays, errors in signal integrity and un-synchronized communication. These problems may be addressed by the use of Network on Chip (NOC) architecture for future SoC. Most future SoCs will use network architecture and a packet based communication protocol for on chip communication. This paper presents an adaptive wormhole routing with proactive turn prohibition to guarantee deadlock free on chip communication for NOC architecture. It shows a simple muting architecture with five full-duplex, flit-wide communication channels. We provide simulation results for message latency and compare results with those of dimension ordered techniques operating at the same link rates.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.2
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• pp.223-230
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• 2008

This paper deals with the measurements of wireless image signal in subway tunnels at 2.45GHz. Measurements have been conducted in 3 subway stations with different types; a straight tunnel and two curved tunnels. As a analysis result for the measured data, we found that the signal level inside straight tunnel by the strong multipath waves fluctuate deeply compared to the curved tunnel. The path loss exponent for the Shin-hung station with the straight tunnel is 2.5, those for the Pan-am and Dae-dong station with curved tunnels are 1.6 and 1.9, respectively. The fade depth and width at 50% point became relatively serious at Shin-hung station, the level crossing rate inside the Pan-am station is larger than the other stations. Therefore, it can be concluded that the fading phenomena affect to the signal performance generate seriously at straight tunnel compared to the curved tunnel.