• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.69-72
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• 2008

In the paper, embedded system that manage, control the status of vehicle through internet and mobile instruments are designed. The network is composed of the distributed control system using CAN communication, where communication is possible with two lines, and the bluetooth, where wireless communication is possible. We also designed the Embedded system to make up the web server only for the vehicle, made it possible to catch hold of the conditions of the vehicle and control the vehicle through internet by interfacing the destributed controller. We also made such a Web Server possible th be monitored and controlled by the mobile instruments such as PDA, mobile phones.

• Industrial Engineering and Management Systems
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• v.15 no.2
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• pp.131-142
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• 2016

We consider a multi-server queueing system without buffer and with two types of customers as a model of operation of a mobile network cell. Customers arrive at the system in the marked Markovian arrival flow. The service times of customers are exponentially distributed with parameters depending on the type of customer. A part of the available servers is reserved exclusively for service of first type customers. Customers who do not receive service upon arrival, can make repeated attempts. The system operation is influenced by random factors, leading to a change of the system parameters, including the total number of servers and the number of reserved servers. The behavior of the system is described by the multi-dimensional Markov chain. The generator of this Markov chain is constructed and the ergodicity condition is derived. Formulas for computation of the main performance measures of the system based on the stationary distribution of the Markov chain are derived. Numerical examples are presented.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1009-1011
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• 1998

This paper presents a design of network and database structure of the integrated system for power system operational planning and analysis that will be more economical and stable of power system operation. An alias of this system is Highly Integrated Total Energy System(HITES). The Client/server model of HITES is designed as a remote data management model. The input/output-type of application programs and Oracle server is standardized. The separated user-databases from main-database strengthen security of HITES. It is plan to do that tables and relationships are defined by database designs. The connection of application program and DBMS of HITES will be tested through database design and data construction.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.2
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• pp.141-147
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• 2018

The group is one of the hobbies and other life groups, and each person in the group directly attends the meeting and works on the topic of the group. In this paper, we implemented voting, announcements, surveys, and suggestions, which are necessary functions for similar groups including group. We also provide web sites based on Apache web server for convenience of Android smartphone applications, OS except Android, Group management can be managed by using the manager's website which can manage the whole group management. It is designed with Apache web server, web communication language PHP, MySQL database, and Android.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2535-2544
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• 2009

The brain-wave research provides relatively various information for brain condition in safety. The counselor or measuree will must easily reduce user TCO about the series of process for the measurement, analysis, and management of brain-wave, and can access to the desired information in real time. While the traditional method for brain-wave process was processed manually by the judgment of a specialist. In this paper the developed system is smart brain-wave care system based on optimizing and combining the 3-Tier client/server by IT with brain-wave technology including BQT. This system was developed in the real-time service with a completely automated process by the conveniently web interface. Our system currently gave a service at the field, and the collected data on DB were provided to researchers for the use of clinical research.

• Information Systems Review
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• v.1 no.1
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• pp.19-33
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• 1999

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.4
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• pp.259-273
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• 2009

Most of large-scale distributed file systems decouple a metadata operation from read and write operations for a file. In the distributed file systems, a certain server named a metadata server (MDS) maintains metadata information in file system such as access information for a file, the position of a file in the repository, the namespace of the file system, and so on. But, the existing systems used restrictive metadata management schemes, because most of the distributed file systems designed to focus on the distributed management and the input/output performance of data rather than the metadata. Therefore, in the existing systems, the metadata throughput and expandability of the metadata server are limited. In this paper, we propose a new non-shared metadata management scheme in order to provide the high metadata throughput and scalability for a cluster of MDSs. First, we derive a dictionary partitioning scheme as a new metadata distribution technique. Then, we present a load balancing technique based on the distribution technique. It is shown through various experiments that our scheme outperforms existing metadata management schemes in terms of scalability and load balancing.

• Journal of Information Processing Systems
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• v.5 no.2
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• pp.69-76
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• 2009

Self healing systems are considered as cognation-enabled sub form of fault tolerance system. But our experiments that we report in this paper show that self healing systems can be used for performance optimization, configuration management, access control management and bunch of other functions. The exponential complexity that results from interaction between autonomic systems and users (software and human users) has hindered the deployment and user of intelligent systems for a while now. We show that if that exceptional complexity is converted into self-growing knowledge (policies in our case), can make up for initial development cost of building an intelligent system. In this paper, we report the application of AHSEN (Autonomic Healing-based Self management Engine) to in OKKAM Project infrastructure backbone cluster that mimics the web service based architecture of u-Zone gateway infrastructure. The 'blind' load division on per-request bases is not optimal for distributed and performance hungry infrastructure such as OKKAM. The approach adopted assesses the active threads on the virtual machine and does resource estimates for active processes. The availability of a certain server is represented through worker modules at load server. Our simulation results on the OKKAM infrastructure show that the self healing significantly improves the performance and clearly demarcates the logical ambiguities in contemporary designs of self healing infrastructures proposed for large scale computing infrastructures.

• International Journal of Internet, Broadcasting and Communication
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• v.8 no.1
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• pp.33-41
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• 2016

Big data management is becoming an increasingly important issue in both industry and academia of information science community today. One of the important categories of big data generated from software systems is log data. Log data is generally used for better services in various service providers and can also be used to improve system reliability. In this paper, we propose a novel big data management architecture specialized for log data. The proposed architecture provides a scalable log management system that consists of client and server side modules for efficient handling of log data. To support large and simultaneous log data from multiple clients, we adopt the Hadoop infrastructure in the server-side file system for storing and managing log data efficiently. We implement the proposed architecture to support various client environments and validate the efficiency through measurement studies. The results show that the proposed architecture performs better than the existing logging architecture by 42.8% on average. All components of the proposed architecture are implemented based on open source software and the developed prototypes are now publicly available.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.12
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• pp.1179-1185
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• 2013

Trend of next generation satellite communication network is distribution and enlargement of network structure with increased network terminals, and traffic which use satellite communication is increasing and frequently occurring. Under specific satellite communication environment that various communication device dynamically forms a network domain and frequently exchanges the data, data-centric publish/subscribe data exchange is more suitable than server/client data exchange. So, this paper analyze DDS performance for application of DDS standard to distribution network management system which aims to efficiently manage limited satellite resource, and also this paper covers comparative study on DDS and SNMP(server/client data exchange). Study compares DDS and SNMP using OPNET, and result of study is analyzed from a network layer performance perspective.