• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.34-42
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• 2012

This paper analyses the energy saving basic power models in core IP networks, and proposes the adaptive buffer and burst scheme which is a possible energy saving method, and its implementation algorithm in core IP networks. Especially this paper describes the adaptive buffer and burst scheme dynamically varying the buffering interval B according to the input traffic volume of ingress router, and explains the operation principle of proposed scheme. This method is to adjust the buffering interval B according to input traffic volume of ingress router, that is increasing the interval B when input traffic volume is low, and decreasing the interval B when input traffic volume is high between some given interval regions. This method can gets the high energy saving effect as decreasing the transition number of idle/active in networks when input traffic volume is low, and decreasing the transition number of idle/active by the continuous of burst packets in transit router when input traffic volume is high. This paper shows the increasing of asleep rate for the energy saving of core IP networks and confirms the energy saving of core IP networks by the computer simulation. We confirmed that proposed method can be save the energy of IP networks by properly trade off network performances.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.5
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• pp.590-597
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• 1985

A recursive geometric adaptive control method to compensate for machining straightness error in the finished surface due to tool deflection and guideway error generated by end milling process is developed. The relationship between the tool deflection and the feedrate is modeled by a modified Taylor's tool life equation. Without a priori knowledge on the variations off cutting parameters, time varying parameters are then estimated by an exponentially windowed recursive least squares method with only post-process measurements of the straightness error. The location error is controlled by shifting the milling bed in the direction perpendicular to the finished surface and adding a certain amount of feedrate with respect to the tool deflection model before cutting. The waviness error is compensated by adjusting the feedrate during machining. Experimental results show that location error is controlled within a range of fixturing error of the bed on the guideway and that about 60% reduction in the waviness error can be achieved within a few steps of parameter adaption under wide operating ranges of cutting conditions even if the parameters do not converge to fixed values.

• Journal of Broadcast Engineering
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• v.21 no.3
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• pp.349-356
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• 2016

In this paper, we propose an efficient assignment method that assigns quantization parameter (QP) in accordance with group of picture (GOP) structure given in HEVC encoder. Each video frames can have difference QP values based on given GOP configuration for HEVC encoding. Particularly, for important frames we can assign low QP values, and vice versa. However, there has not been thorough investigation on efficient QP assignment method by far. Even in HEVC reference software encoder, only monotonic QP assignment method is employed. Thus, the proposed method assign adaptive QP values to each GOP so that temporal dynamic activity between GOPs can be exploited. Through the experiment, the proposed method showed a 7.3% gain of compression performance in terms of BD-rate compared to HEVC test model (HM) in low-delay configuration, and outperformed the existing QP assignment study on average.

• Journal of KIISE:Information Networking
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• v.31 no.5
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• pp.482-489
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• 2004

Paging extensions for Mobile IP was proposed to avoid unnecessary registration signaling overhead of Mobile IP. In order to support the paging function in Mobile IP, the slates of a mobile node arc divided into active on, active off, idle. The active on state means when any incoming or outgoing data session arrives to a mobile node. After data session is completed, the state of the motile node is changed into active off from active on. At this moment, the active timer starts to be operated. If the active timer expires, the mobile node moves to idle state. If a mobile node has very frequently data sessions at the same cell, the mobile node is better to move slowly into idle state. The other way, if the mobile node very frequently moves into new cell area and receives or sends little data, the mobile node is better to move earlier into idle state. In this raper, the active timer is adaptively set by the mobile nodes traffic and mobility characteristics and the paging scheme using this active timer is proposed to reduce the location registration cost.

• Journal of Korea Multimedia Society
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• v.12 no.10
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• pp.1418-1426
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• 2009

There has been a lot of interest in an effective method for background subtraction in an effort to separate foreground objects from a predefined background image. Promising results on background subtraction using statistical methods have recently been reported are robust enough to operate in dynamic environments, but generally require very large computational resources and still have difficulty in obtaining clear segmentation of objects. We use a simple running-average method to model a gradually changing background, instead of using a complicated statistical technique. We employ a single global threshold vector, optimized by a genetic algorithm, instead of pixel-by-pixel thresholds. A new fitness function is defined and trained to evaluate segmentation result. The system has been implemented on a PC with a webcam, and experimental results on real images show that the new method outperforms an existing method based on a mixture of Gaussian.

• The KIPS Transactions:PartD
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• v.11D no.5
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• pp.1177-1188
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• 2004

Multi-agent systems have been developed for supporting intelligent collaboration of distributed and independent software entities and are be-ing widely used for various applications. For the collaboration among agents, conversation policies (or interaction protocols) mutually agreed by agents are used. In today's dynamic electronic market environment, there can be frequent changes in conversation policies induced by the changes in transaction methods in the market, and thus, the importance of ad hoc conversation policies is increasing. In existing agent platforms, they allow the use of only several standard or fixed conversation policies, which requires inevitable re implementation for ad hoc conversation policies and leads to inefficiency and intricacy. This paper designs an agent platform that supports ad hoc conversation policies and presents the prototype implementation. The suggested system includes an exchangeable and interpretable conversation policy model, a meta conversation procedure for exchanging new conversation policies, and a mechanism for performing actual transactions with exchanged conversation policies in run time in an adaptive way.

• Journal of Digital Convergence
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• v.15 no.6
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• pp.229-236
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• 2017

An efficient frequent pattern algorithm is essential for mining association rules as well as many other mining tasks for convergence with its application spread over a very broad spectrum. Models for mining pattern have been proposed using a FP-tree for storing compressed information about frequent patterns. In this paper, we propose a centroid frequent pattern growth algorithm which we called "CAWFP-Growth" that enhances he FP-Growth algorithm by making the center of weights and frequencies for the itemsets. Because the conventional constraint of maximum weighted support is not necessary to maintain the downward closure property, it is more likely to reduce the search time and the information loss of the frequent patterns. The experimental results show that the proposed algorithm achieves better performance than other algorithms without scarifying the accuracy and increasing the processing time via the centroid of the items. The MapReduce framework model is provided to handle large amounts of data via a pseudo-distributed computing environment. In addition, the modeling of the proposed algorithm is required in the fully distributed mode.

• The Transactions of the Korea Information Processing Society
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• v.7 no.8
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• pp.2310-2326
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• 2000

Client-server DBMS based on a data-shipping model can exploit e1ient resources effectively by allowing inter-transaction caching. However, inter-transaction caching raises the need of transactional cache consistency maintenancetTCCM protocol. since each client is able to cache a portion of the database dynamically. Deferred locking(DL) is a new detection-based TCCM scheme designed on the basis of a primary copy locking algorithm. In DL, a number of lock ,ujuests and a data shipping request are combined into a single message packet to minimize the communication overhead required for consistency checking. Lsing a simulation model. the performance of the prolxlsed scheme is compared with those of two representative detection based schemes, the adaptive optimistic concurrency control and the caching two-phase locking. The performance results indicate that DL improves the overall system throughput with a reasonable transaction abort ratio over other detection - based schemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.2C
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• pp.188-195
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• 2012

Many systems are developing for the realization of NCW(Network Centric Warfare). UAV(Unmanned Aerial Vehicle) Network is attracting attention in a lot of military applications. In general, UAVs have the potential to create an ad-hoc network and greatly reduce the hops from source to destination. However, UAV networks exhibit unique properties such as high mobility, high data rate, and real time service. The routing protocols are required to design the multi-hop routing protocols that can dynamically adapt to the requirements of UAV network. In this paper we analyse Geographic Routing Protocol is based on geographical distance between source and destination for efficient and reliable transmission. Geographic Routing Protocol is evaluated in video service scenarios with TDMA model in our simulation. The simulation results show that the performance of Geographic Routing Protocol is better than the MANET Routing Protocol in terms of packet received ratio, end to end delay, and routing traffic sent.

• Journal of the Korea Society for Simulation
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• v.20 no.1
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• pp.51-59
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• 2011

This paper is concerned with locomotion of dog-like quadruped robots that can adapt to various terrains, mainly dealing with implementation methods and characteristics of static and dynamic gaits. To this end, a 12-DOF robot is built in house, motional trajectories of its body and feet are generated mimicking biological life, and the corresponding leg joint angles are analytically obtained by inverse kinematics. Such joint angle data are then applied to the robot's ADAMS model for computer simulations so that the planned walk and trot gaits are both confirmed dynamically stable. However, contrary to the simulation results, previous trot patterns showed unstable behavior during experiments. This problem led us to analyze the reason, and in the course we discovered the importance of maximally utilizing the concept of WSM rather than ZMP and therefore reducing the gait period to secure the stability of dynamic gaits such as trot.