• The KIPS Transactions:PartC
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• v.14C no.2
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• pp.171-178
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• 2007

In mobile ad hoc networks, an application scenario requires mostly group mobility behavior in the mix of group moving nodes and individually moving nodes. The nodes of those applications tend to belong to the movement group with similar movement behavior. Group mobility is one of the good methods to improve scalability, and reduces the protocol overhead. In this paper, we propose the multicast architecture which regards nodes that have equal group mobility in the heterogeneous group mobility network as the single entity with the multiple interfaces and composes multicast tree, The logical cooperative entity-based multicast architecture accommodates the scalability, the multicast tree simplification, and the protocol overhead reduction which arc obtained from the hierarchical multicast architecture, while it maintains the nat multicast architecture for the data transmission. It also prevents the concentration of the energy consumption dispersing data forwarding load into the several ingress/egress nodes. Results obtained through simulations show that logical cooperative entity based multicast protocol with multiple interfaces offers the protocol scalability and the efficient data transmission.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.4
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• pp.389-395
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• 2006

This paper proposes the controller for biped robot using intelligent control algorithm. In order to simplify the complexity of biped robot control, manipulator of biped robot is divided into four modules. These modules are controlled by intelligent algorithm with Hierarchical Mixture of Experts(HME) using neural network. Also neural network having direct control method learns the inverse dynamics of biped robot. The HME, which is a network of tree structure, reallocates the input domain for the output by learning pattern of input and output. In this paper, as a result of learning HME repeatedly with EM algorithm, the controller for biped robot operating safety walking is designed by modelling dynamics of biped robot and generating virtual error of HME.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1438-1443
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• 2016

In this paper, we investigate the effect of multiple antennas at a relay node on the performance of physical-layer network coding (PNC) in the two-way relay channel (TWRC). We assume that two source nodes have a single antenna and the relay node has multiple antennas. We extend the conventional TWRC environment with a signle antenna at both relay and source nodes to the case of multiple antennas at the relay node. In particular, we consider two decoding strategies: separate decoding (SD) and direct decoding (DD). The SD decodes each packet from the two sources and performs the network coding with bit-wise exclusive OR (XOR) operation, while the DD decodes the network-coded packet from the two sources. Note that both decoding strategies are based on log-likelihood ratio (LLR) computation. It is shown that the bit error rate (BER) performance becomes significantly improved as the number of antennas at the relay node.

• The KIPS Transactions:PartD
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• v.18D no.2
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• pp.133-142
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• 2011

To ensure the successful employment of semantic web services, it is essential that they rely on the use of high quality ontologies. However, building such ontologies is difficult and costly, thus hampering web service deployment. This study automatically builds ontologies from WSDL documents and their underlying semantics, and presents discovery methods of similar web service operations using these ontologies. The key ingredient is techniques that cluster parameters in the collection of web services into semantically meaningful concepts, and capture the hierarchical relationships between the words contained in the tag. We implement an operation retrieval system for web services. This system finds out a ranked set of similar operations using a novel similarity measurement method, and selects the most optimal operation which satisfies user's requirements. It can be directly used for the web services composition.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.5
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• pp.619-633
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• 1993

A new High level hardware Description Language, ASPHODEL(Algorithm Synthesis Pascal Hardware for Optimal Design and Efficient Language), and its algorithm compiler for high level synthesis are described in this paper. The new HDL, appropriated to the description of algorithmic level and lower, models VLSI circuits as an abstracted block which is consisted of input/output ports and hierachical processors to control VLSI complexities with efficiency. Also, in order to improve the descriptive power, popular Pascal programming language is modified to build ASPHODEL syntax rules. ASPHODEL algorithm compiler generates an intermediate form through lexical and syntax analysis from ASPHODEL source codes. To show the validation of presented language and its compiler, those are applied to practical design examples.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1976-1981
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• 2013

In this paper, we propose a frequency-domain interference cancellation algorithm for direct-sequence spread spectrum systems. In the previously proposed frequency-domain interference cancellation algorithms that protocol defines the rules concerning the collection of means of Transmission Control Protocol (TCP: Transmission Control Protocol) is the most widely used in the transport layer. Two-way traffic through the network path to the same end-to-end transfer of data in the opposite direction between pairs of nodes are infused with two or more TCP connection using the network traffic patterns from the exchanger and routers share results of approval. Per-flow input/output structure of matter using the LTS online reaction when evaluated as this is the most important factor. TCP-MT when the connection duration is one of the largest performance gains.

• The KIPS Transactions:PartD
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• v.15D no.5
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• pp.589-598
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• 2008

Recently, Mobile Computing Devices are used generally. And Information which is processed by Mobile computing devices is increasing. Because information is digitalizing. So Mobile computing Devices demand an Embedded DBMS for efficient management of information. Moreover Mobile computing Devices demand an efficient storage management in NAND-type flash memory because the NAND-type flash memory is using generally in Mobile computing devices and the NAND-type flash memory is more expensive than the magnetic disks. So that in this paper, we present an efficient Compressed Data Management System for the embedded DBMS that is used in flash memory. This proposed system improve the space utilization and extend a lifetime of a flash memory because it decreases the size of data.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.2
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• pp.77-88
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• 2009

According to the size of NAND flash memory as the storage system of mobile device becomes large, the performance of address translation and life cycle management in FTL (Flash Translation Layer) to interact with file system becomes very important. In this paper, we propose the continuity counters, which represent the number of continuous physical blocks whose logical addresses are consecutive, to reduce the number of address translation. Furthermore we propose the prefetching method which preloads frequently accessed pages into main memory to enhance I/O performance of flash memory. Besides, we use the 2-bit write prediction and asynchronous writing method to predict addresses repeatedly referenced from host and prevent from writing overhead. The experiments show that the proposed method improves the I/O performance and extends the life cycle of flash memory. As a result, proposed CFTL (Clustered Flash Translation Layer)'s performance of address translation is faster 20% than conventional FTLs. Furthermore, CFTL is reduced about 50% writing time than that of conventional FTLs.

• The KIPS Transactions:PartA
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• v.15A no.6
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• pp.335-344
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• 2008

We propose an adaptive garbage collection technique for hybrid flash memory which has both SLC and MLC. Since SLC area is fast and MLC area has low cost, the proposed scheme utilizes the SLC area as log buffer and the MLC area as data block. Considering the high write cost of MLC flash, the garbage collection for the SLC log buffer moves a page into the MLC data block only when the page is cold or the page migration invokes a small cost. The other pages are moved within the SLC log buffer. Also it adjusts the parameter values which determine the operation of garbage collection adaptively considering I/O pattern. From the experiments, we can know that the proposed scheme provides better performance compared with the previous flash management schemes for the hybrid flash and finds the parameter values of garbage collection close to the optimal values.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1405-1411
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• 2022

Power management is still an important issue in embedded environments as hardware advances like high-performance processors. Power management methods such as DVFS control CPU frequencies in an adaptive manner for efficient power management in polling-based I/O programs such as network communication. This paper presents the problems of the existing power management method and proposes a new power management method. Through this, it is possible to reduce electric consumption by increasing the polling cycle in situations where the frequency of data reception is low, and on the contrary, in situations where data reception is frequent, it can operate at the maximum frequency without performance degradation. After implementing this as a code layer on the embedded board and observing it through Atmel's Power Debugger, the proposed method showed a performance improvement of up to 30% in energy consumption compared to the existing power management method.