• Journal of Communications and Networks
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• v.6 no.3
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• pp.197-202
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• 2004

This work presents a stability analysis of the synchronous state for one-way master-slave time distribution networks with single star topology. Using bifurcation theory, the dynamical behavior of second-order phase-locked loops employed to extract the synchronous state in each node is analyzed in function of the constitutive parameters. Two usual inputs, the step and the ramp phase perturbations, are supposed to appear in the master node and, in each case, the existence and the stability of the synchronous state are studied. For parameter combinations resulting in non-hyperbolic synchronous states the linear approximation does not provide any information, even about the local behavior of the system. In this case, the center manifold theorem permits the construction of an equivalent vector field representing the asymptotic behavior of the original system in a local neighborhood of these points. Thus, the local stability can be determined.

• The Journal of the Korea Contents Association
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• v.16 no.2
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• pp.163-173
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• 2016

Recently, massive amounts of stream data have been studied for distributed processing. In this paper, we propose an incremental stream data processing method based on in-memory in big data environments. The proposed method stores input data in a temporary queue and compare them with data in a master node. If the data is in the master node, the proposed method reuses the previous processing results located in the node chosen by the master node. If there are no previous results of data in the node, the proposed method processes the data and stores the result in a separate node. We also propose a job scheduling technique considering the load and performance of a node. In order to show the superiority of the proposed method, we compare it with the existing method in terms of query processing time. Our experimental results show that our method outperforms the existing method in terms of query processing time.

• Journal of Communications and Networks
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• v.1 no.2
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• pp.89-98
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• 1999

In a synchronization (sync) $network^1$containing N nodes, it is shown (Theorem 1c) that an arbitrarily connected sync network & is the union of a countable set of isolated connecting sync networks${&_i,i= 1,2,.., L}, I.E., & = \bigcup_{I=1}^L&_i$ It is shown(Theorem 2e) that aconnecting sync network is the union of a set of disjoint irreducible subnetworks having one or more nodes. It is further shown(Theorem 3a) that there exists at least one closed irreducible subnetwork in $&_i$. It is further demonstrated that a con-necting sync network is the union of both a master group and a slave group of nodes. The master group is the union of closed irreducible subnetworks in $&_i$. The slave group is the union of non-colsed irre-ducible subnetworks in $&_i$. The relationships between master-slave(MS), mutual synchronous (MUS) and hierarchical MS/MUS ent-works are clearly manifested [1]. Additionally, Theorem 5 shows that each node in the slave group is accessible by at least on node in the master group. This allows one to conclude that the synchro-nization information avilable in the master group can be reliably transported to each node in the slave group. Counting and combinatorial arguments are used to develop a recursive algorithm which counts the number $A_N$ of arbitrarily connected sync network architectures in an N-nodal sync network and the number $C_N$ of isolated connecting sync network in &. EXamples for N=2,3,4,5 and 6 are provided. Finally, network examples are presented which illustrate the results offered by the theorems. The notation used and symbol definitions are listed in Appendix A.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.3
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• pp.1-4
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• 2010

RS-485, communication bases from small network system must prepare in collision. The collision is that mean the data transfer breaks. For a stabilized communication chooses 1:N polling methods. But polling is low speed in addition to maybe overload Master device. So, usual N:N Prefers a communication. In this case, must be preparing to avoid collision or some solutions. Generally, to after collision retransmits after short time. It's called delay time for short time. When making a delay time, uses address of each systems. (Address of each node) If the many nodes collided, the each node has different delay time. When making a delay time, uses a usual random number. Making a random number is hard job. So uses a usual pseudorandom number. It is more difficult from small size MCU. The Chaos random number provides stabled value. Finally, when uses the Chaos random number, the stability and reliability of system get better.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.176-179
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• 2002

In recent years, an increasing amount of computer network research has focused on the problem of cluster system in order to achieve higher performance and lower cost. The load unbalance is the major defect that reduces performance of a cluster system that uses parallel program in a form of SPMD (Single Program Multiple Data). Also, the load unbalance is a problem of MPP (Massive Parallel Processors), and distributed system. The cluster system is a loosely-coupled distributed system, therefore, it has higher communication overhead than MPP. Dynamic load balancing can solve the load unbalance problem of cluster system and reduce its communication cost. The cluster systems considered in this paper consist of P heterogeneous nodes connected by a switch-based network. The master node can predict the average execution time of tasks for each slave node based on the information from the corresponding slave node. Then, the master node redistributes remaining tasks to each node considering the predicted execution time and the communication overhead for task migration. The proposed dynamic load balancing uses execution time prediction to optimize the task redistribution. The various performance factors such as node number, task number, and communication cost are considered to improve the performance of cluster system. From the simulation results, we verified the effectiveness of the proposed dynamic load balancing algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2198-2202
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• 2003

The data transmission of MVB(Multifunction Vehicle Bus) of TCN(Train Network Communication) is divided into the periodic transmission phase and the sporadic transmission phase. TCN standard defines the event-polling method for the message transfer in the sporadic phase. However, since the event-polling method does not use pre-scheduling to the priority of the messages to be transmitted, it is inefficient for the real-time systems. To schedule message transmission, a master node should know the priority of message to be transmitted by a slave node prior to the scheduling the sporadic phase, but the existing TCN standard does not support any protocol for this. This paper proposes the slave frame bit-stuffing algorithm, with which a master node gets the necessary information for transmission scheduling and includes the simulation results of the event-polling method and the proposed algorithm.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.10
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• pp.720-726
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• 2004

The data transmission over MVB(Multifunction Vehicle Bus) of TCN(Train Communication Network) is divided into the periodic transmission phase and the sporadic transmission phase. TCN standard recommends the event-polling method as the message transfer in the sporadic phase. However, since the event-polling method does not use pre-scheduling to the priority of the messages, it is inefficient for the real-time systems. To schedule message transmission, a master node should know the priority of message to be transmitted by a slave node prior to the sporadic phase, but the existing TCN standard does not support any protocol for this. This paper proposes the slave frame bit-stuffing algorithm, with which a master node gets the necessary information for scheduling and includes the simulation results of the event-polling method and the proposed algorithm.

• Journal of Internet of Things and Convergence
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• v.6 no.4
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• pp.81-87
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• 2020

This paper creates a standard node for acquiring sensor data from various industrial sensors (IoT/non-IoT) for the establishment of Smart Factory Digital Twin, and provides inter-compatible data by linking zones by group/process to secure data stability and to ensure the digital twin (Digital Twin) of Smart Factory. The process of the Zone Master platform contains interface specifications to define sensor objects and how sensor interactions between independent systems are performed and carries out individual policies for unique data exchange rules. The interface for execution control of the Zone Master Platform processor provides system management, declaration management for public-subscribe, object management for registering and communicating status information of sensor objects, ownership management for property ownership sharing, time management for data synchronization, and data distribution management for Route information on data exchange.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.3
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• pp.73-78
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• 2019

Due to frequent topology changes in wireless networks, inter-node link disconnection and path re-establishment occur, causing problems such as overloading control messages in the network. In this paper, to solve the problems such as link disconnection and control message overload, we perform path setup in three steps of the neighbor node discovery process, the route discovery process, and the route management process in the wireless network environment. The link stability value is calculated using the information of the routing table. Then, when the zone master monitors the calculated link value and becomes less than the threshold value, it predicts the link disconnection and performs the path reset to the corresponding transmitting and receiving node. The proposed scheme shows a performance improvement over the existing OLSR protocol in terms of data throughput, average path setup time, and data throughput depending on the speed of the mobile node as the number of mobile nodes changes.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.35-45
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• 2006

Coordinator is defining so that function as most trust center that is point in security in ZigBee Alliance. Because must do height connection with coordinator in device signing to PAN newly, coordinator has shortcoming that subordinate is revealed to danger directly to Centered and cattish device. When do height connection some device, do not become problem, but if network is huge, coordinator's subordinate shall increase as traffic quantity which happen in coordinator increases. Also, in ZigBee security to link network kina of transmission and mutually certification in ZigBee Alliance standard include, but I do not provide method to deliver master key in each node safely. Because process that transmit master key passes through channel that do not secure, master key has shortcoming that is revealed directly. In this paper, I suggested Parent-Child key establishment algorithm to solve these problem. Proposed algorithm consists of two structures. Master key establishment algorithm and device that sign to PAN newly that can use one-way Hash chain and transmit master key safety are consisted of Parent-Child network key establishment algorithm that do child node and parent node key establishment as can do key establishment efficiently. Method that device proposes in case method that propose in case have master key establishment time was shown better performance $200{\sim}1300ms$ than existing method, and device does not have master key than existing method height connect time about $400{\sim}500ms$ better performance see.