• Journal of the Korean Institute of Intelligent Systems
• /
• v.8 no.2
• /
• pp.21-34
• /
• 1998

[n this paper, we propose a hierarchical self-organizing fuzzy logic controller to improve the performance of the FARMA(Fuzzy auto-regressive moving average) SOC(Self-organizing fuzzy logic controller) when the system parameters change. The proposed controller contains the FARMA SC)C in the lower level and has a coordinator in the higher level, which evaluates convergence. and when it senses the degradation of system performance it compensates the control input by a look-up table. The proposed controller shows good perforniance over the FARMA SOC when the system parameters change. We executed some computer simulations on the regulation problem of an inlrerted pendulum system and compared the results with those of the FARMA SOC. As a result, it ha:; been shown that the proposed controller outperformed the FARMA SOC when the changes of the system parameters occurred.

• The Transactions of the Korea Information Processing Society
• /
• v.3 no.4
• /
• pp.938-946
• /
• 1996

Hierarchical subband codec has been widely promoted in the field of data compression/decompression because of their simplicity and modular nature. Over the past years, the study has received great attention to the perfect reconstruction (PR)system which perfectly recovers the original input signal at the reconstructed output. However, in the actual subband codec system, the signals that passed through the analysis filter bank are quantized before transmission to the receiver side and reconstructed by the synthesis filter bank. Thus the PR system is impossible and the quantization effects must be carefully considered in the system design such that the system recovers the reconstructed output as possible to the the original input signal with minimum quantization error.In this paper, we propose an optimum hierarchical subband codec structure in the presence of quantizer. The optimality criteria of the code is given to the deign of the hierarchical analysis/synthesis subband filter bank and the quantizer that minimize then output mean square error due to the quantizer in the codec. Specific opti-mum design esamples are shown with level-1, level-2 hierarchical structure. The optimal designs are verified by computer simulation.

• Proceedings of the Korean Information Science Society Conference
• /
• 2002.04a
• /
• pp.460-462
• /
• 2002

본 논문에서는 기존의 망 관리 시스템의 관리가 시간, 장소, 벤더에 종속되고 개발시에 시스템 전반을 설계 구현해야 한다는 단점을 보안하기 위하여 J2EE (Jaya 2 Enterprise Edition) 기술을 사용하는 컴포넌트 기반의 다중 계층 구조를 갖는 망 관리 시스템을 제안하며, J2EE 기반 망 관리 시스템의 프리젠테이션 프레임워크를 설계한다. 본 망 관리 시스템의 프리젠테이션 프레임워크는 웹 브라우저, WAP (Wireless Application Protocol) 단말기, PCS (Personal Communication System) 등의 모든 다양한 Internet 장비들을 망 관리 인터페이스로 제공하기 위하여 자바 빈즈, 서블릿, JSP (Java ServerPage), XML (eXtensible Markup Language), J2ME (Java 2 Micro Edition) 기술 등을 사용하여 설계한다.

• The Journal of the Acoustical Society of Korea
• /
• v.21 no.8
• /
• pp.719-726
• /
• 2002

In this paper, we present a layered watermarking technique for digital audio data that is capable of detecting timing change and adapting complexity in detection. The proposed watermarking uses echo hiding as the first layer, which enables the detector to estimate linear speed change. The spread spectrum watermark is then inserted in the second layer which includes additional information like copyright data. We use two kinds of sequences in the second layer, one of which is for synchronization and the other is for data. The results of previous layer are used to make estimate of timing change in the next layer. The detector in the presented method can select detecting range form the first layer to the first layer, second pre-layer, or second main-layer due to the required system specification. Experimental results show that the proposed watermarking technique is robust to several processing attacks including timing change.

• The KIPS Transactions:PartC
• /
• v.12C no.4 s.100
• /
• pp.551-558
• /
• 2005

In this paper, we implement the fast handovers for mobile IPv6 (FMIPv6) on Linux system. Due to its dependency on operations in layer-2 (L2), we have added some functions into the network driver to generate triggers as the mobile node moves. We design and implement the FMIPv6 functions divided into two parts as an access router and a mobile node. We compare the packet loss and delay of the FMIPv6 implementation during the handover period with those of the MIPv6 and investigate the performance improvement.

• Journal of Digital Convergence
• /
• v.15 no.1
• /
• pp.427-433
• /
• 2017

Mobile game users tend to value the opinions from their friends or SNS when making a decision on which game to play. This is because they are not satisfied with the information on suggestions provided by the conventional mobile game recommendation systems. In this research, we made a system that can reflect user preference directly by using Analytic Hierarchy Process(AHP). In the system, the hierarchy of AHP is composed of final goal(Level 1), evaluation basis(Level 2) and alternative(Level 3). And the system is made up of an input module, an AHP processing module, a recommendation module and database. Through comparison analysis with two conventional systems to test the performance of the system, we could find that the system got more higher satisfaction than the other systems.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.2
• /
• pp.126-130
• /
• 2006

Programmable Logic Controller(PLC) is the most widely utilized and plays an important role in industrial control system. Sequential Function Chart(SFC) is a graphic language which is suitable for describing a sequential control logic in discrete control system. We can design a distribute control construction and a hierarchical control construction in process control system described by SFC. In hierarchical control structure, we construct each subsystems to synchronize a synchronous signal between subsystems, and the command system gives and takes a synchronous signal with subsystems. Therefore, the system has a low memory efficiency and a low system performance. In this paper, we propose the method that improved the efficiency of memory in hierarchical control construction, and confirm its feasibility through an actual example.

• Journal of KIISE:Computer Systems and Theory
• /
• v.36 no.2
• /
• pp.102-110
• /
• 2009

The memory wall is the growing disparity of speed between CPU and memory outside the CPU chip. An economical solution is a memory hierarchy organized into several levels, such as processor registers, cache, main memory, disk storage. We introduce a novel memory hierarchy optimization technique in Linux based embedded systems using on-chip SRAM for the first time. The optimization technique allocates On-Chip SRAM to the code/data that selected by programmers by using virtual memory systems. Experiments performed with nine applications indicate that the runtime improvements can be achieved by up to 35%, with an average of 14%, and the energy consumption can be reduced by up to 40%, with an average of 15%.

• Journal of Broadcast Engineering
• /
• v.14 no.6
• /
• pp.721-732
• /
• 2009

AT-DMB system has been developed to increase data rate up to double of conventional T-DMB in same bandwidth while maintaining backward compatibility. The AT-DMB system adopted hierarchical modulation which adds BPSK signal or QPSK signal as enhanced layer to existing DQPSK signal. The enhanced layer signal should be small enough to maintain backward compatibility and to minimize the coverage loss of existing T-DMB service area. But this causes the enhanced layer signal of AT-DMB susceptible to fading effect in transmission channel. A turbo code which has powerful error correction capability is applied to the enhanced layer signal of the AT-DMB system for compensating channel distortion. We developed the prototype AT-DMB transmitter and receiver systems for performance evaluation. LAB test for analysing the effect of constellation ratio between existing base layer signal and enhancement layer signal, was conducted and the measurement results are shown with analysis comments.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.21 no.2
• /
• pp.212-217
• /
• 2011

In this paper, we developed an intelligent minimized integrated digital public address which can provide context awareness of various events occurring in future intelligent buildings. It is able to recognize both voices and sounds, such as a fire bell and a disaster bell, which signal to escape in emergence situations and it can sense information which is sent from various sensors, for example, the inner temperature, humidity, and environment status in an intelligent building. Also, the intelligent digital integrated public address can broadcast information to individual places, according to context awareness that is from sensing information, by using network with an ID. And we are developing a minimized integrated digital public address system that has facilities such as external input, Mic., CD, MP3 and Radio. Developing an integrated digital public address system with operational MICOM will make it possible to control the facilities of digital devices centrally. The operational MICOM is composed of 3 layers which are a control layer, a processing layer and a user interface layer.