• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.101-111
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• 2011

A new MAC protocol, MT-MAC(Multi-Tier Medium Access Control) by name, is proposed for dense sensor networks. Depending on the density of nodes in a virtual cluster, the cluster header performs the splitting to several tiers in nodes of virtual cluster. MT-MAC split the tiers to use modfied-SYNC message after receiving the beacon message from the cluster header. Because only the sensor nodes in the same tier communicate each other, less power is consumed and longer network life time is guaranteed. By a simulation method with NS-2, we evaluated our protocol. In dense nodes environments, MT-MAC protocol shows better results than S-MAC in terms of packet delivery rates throughput and energy consumption.

• Journal of Biosystems Engineering
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• v.31 no.5 s.118
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• pp.436-442
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• 2006

This research was conducted to design and develop a wired monitoring system for judging if sick or dead layers (SDL) exist in multi-tier layers battery (MLB) by machine vision, and to analyze its performance. In this study, 20 Brown Leghorn (Hi-Brown) layers aged 37 weeks old, were used as the experimental animals. The intensity of concern paid by layers on feed was over 90% during 5 minutes and 30 seconds after providing feed, and normal layers (NL) had been standing to take feed for that period. Therefore, in this study, the optimal judging time was set by this test result. The wired monitoring system developed was consisted of a driving device for carrying machine vision systems, a control program, a RS232 to RS485 convertor, an automatic positioning system, and an image capture system. An image processing algorithm was developed to find SDL in MLB by the processes of binary processing, erosion, expansion, labeling, and reckoning central coordinate of the captured images. The optimal velocity for driving unit was set up as 0.13 m/s by the test results for wired monitoring system, and the proximity switch was controlled not to be operated for 1.0 second after first image captured. The wired monitoring system developed was tested to evaluate the remote monitoring performance at lab-scale laying hen house. Results showed that its judgement success.ate on normal cage (without SDL) was 87% and that on abnormal cage (with SDL) was 90%, respectively. Therefore, it would be concluded that the wired monitoring system developed in this study was well suited to the purpose of this study.

• KNOM Review
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• v.23 no.2
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• pp.1-10
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• 2020

Network Function Virtualization (NFV) is a key technology of 5G networks that has the advantage of enabling building and operating networks flexibly. However, NFV can complicate network management because it creates numerous virtual resources that should be managed. In NFV environments, service function chaining (SFC) composed of virtual network functions (VNFs) is widely used to apply a series of network functions to traffic. Therefore, it is required to dynamically allocate the right amount of computing resources or instances to SFC for meeting service requirements. In this paper, we propose Deep Q-Networks (DQN)-based auto-scaling to operate the appropriate number of VNF instances in SFC. The proposed approach not only resizes the number of VNF instances in SFC composed of multi-tier architecture but also selects a tier to be scaled in response to dynamic traffic forwarding through SFC.

• Journal of the Korean earth science society
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• v.41 no.3
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• pp.291-306
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• 2020

In this study, we developed a learning progression for the structure of the solar system using multi-tier supply form items and validated its appropriateness. To this end, by applying Wilson's (2005) construct modeling approach, we set up 'solar system components,' 'size and distance pattern of solar system planets,' and 'solar system modeling' as the progress variables of the learning progression and constructed multi-tier supply form items for each of these variables. The items were applied to 150 fifth graders before and after the classes that dealt with the 'solar system and star' unit. To describe the results of the assessment, the students' responses to each item were categorized into five levels. By analyzing the Wright map that was created by applying the partial credit Rasch model, we validated the appropriateness of the learning progression based on the students' responses. In addition, the validity of the hypothetical pathway that was established in the learning progression was verified by tracking changes in the developmental level of students before and after the classes. The results of the research are as follows. The bottom-up research method that used multi-tier supply form items was able to elaborately set the empirical learning progression for the conceptualization of the structure of the solar system that is taught in elementary school. In addition, the validity of the learning progression was high, and the development of students was found to change with the learning progression.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.822-825
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• 2002

Geographic Information System(GIS) has become an essential tool for making efficient interaction with both natural and artificial envirionment. Currently, it is being used on an inteligent tool in many device like the personal digital assistant(PDA) and the cellular phone and so on. However, these devices show very low performance comparing to a personal computer(PC). These devices(PDA, celluar phone) posses a less powered device profile. The less powerful hardware make these devices in capable to handle GIS based large spacial data. In this paper, we propose a new concept of multi-tier GIS oriented architecture to improve the data transfer performance providing only the necessary information required by the user using semantic filter.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4291-4310
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• 2015

This paper investigates the traffic offloading over unlicensed bands for two-tier multi-mode small cell networks. We formulate this problem as a Stackelberg game and apply a hierarchical learning framework to jointly maximize the utilities of both macro base station (MBS) and small base stations (SBSs). During the learning process, the MBS behaves as a leader and the SBSs are followers. A pricing mechanism is adopt by MBS and the price information is broadcasted to all SBSs by MBS firstly, then each SBS competes with other SBSs and takes its best response strategies to appropriately allocate the traffic load in licensed and unlicensed band in the sequel, taking the traffic flow payment charged by MBS into consideration. Then, we present a hierarchical Q-learning algorithm (HQL) to discover the Stackelberg equilibrium. Additionally, if some extra information can be obtained via feedback, we propose an improved hierarchical Q-learning algorithm (IHQL) to speed up the SBSs' learning process. Last but not the least, the convergence performance of the proposed two algorithms is analyzed. Numerical experiments are presented to validate the proposed schemes and show the effectiveness.

• The KIPS Transactions:PartB
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• v.12B no.7 s.103
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• pp.789-794
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• 2005

The multimedia system using computing environment should support the fast access speed on the large scaled high quality data in the functional side. And it can support interaction and adaptiveness on system users. But it is hard to support it all effectively in the existing multimedia systems. In this paper, we design the multi-tier hybrid multimedia system. The proposed system is based on the characteristics of a multimedia medium, and it has the merits of the CD-ROM based method and the web based method. On the experiments, we verified the efficiency of the proposed system.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.6
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• pp.587-598
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• 2013

In Korea military (KM), various military supplies are distributed to individual military units via three different multi-tier supply networks owned and operated by army, navy, and air force, respectively. Under the current supply networks, the chances for the occurrence of delayed supply, undersupply, and oversupply increase, and supply redundancy also can become a problem. Thus, KM is now trying to improve its current multi-tier supply networks by constructing logistics consolidation centers. Private companies operate logistics consolidation centers to effectively manage various types of inventories before delivering them to final customers. In this paper, we newly propose a mathematical model for building the optimized military supply network considering adopting the military logistics consolidation centers. Based on the real situation of KM, the proposed model was validated in terms of its feasibility, and it seems that the outcome (the location of the military logistics consolidation centers) of the proposed model can be one of the good alternatives for KM.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.5
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• pp.428-433
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• 2004

In this paper, we developed a multi-protocol controller based on SoC and embedded Linux and applied it to integrate with BAS in a unified TCP/IP socket communication. The multi-protocol controller integrates control networks of RS-485 and LonWorks devices to BAS. The system consists of three-tier architecture, such as a BAS, a multi-protocol converter, and control devices. By using UML, we modeled the system architecture. In order to show the feasibility of system architecture, it was applied to a small BAS system. The experimental results show that the multi-protocol controller using embedded Linux is flexible and effective way to develop a building control system.

• The Journal of the Korea Contents Association
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• v.1 no.1
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• pp.51-58
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• 2001

Electronic commerce system must provide convenient interface, easy and fast searching function, and production information satisfying customers. To do this, many kinds of studies are being advanced actively about electronic commerce system using intelligent agent electronic This paper suggests 2-tier electronic commerce system using intelligent multi agent. We propose a combined reasoning agent system which provides production information satisfying customer's needs using both case-based reasoning and rule-based reasoning. And this system distribute network and sewer system load based on load balancing and 2-tier agent structure. This system can find production information through teaming of rule-based reasoning method and case-based reasoning method. This system can provide the best suitable production information to customers by using combined reasoning agent system. And we can prevent customer's unexpected long waiting causes by network traffic and server load.