• Journal of Institute of Control, Robotics and Systems
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• v.3 no.6
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• pp.555-562
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• 1997

With only the classical PID controller applied to control of a DC motor, good (target) performance characteristic of the controller can be obtained if all the model parameters of DC motor and operating conditions such as external load torque, disturbance, etc. are known exactly. However, in case when some of system parameters or operating conditions are uncertain or unknown, the fixed PID controller does not guarantee good performance, which is assumed with precisely known system parameters and operating conditions. In view of this and the robustness enhancement of DC motor control system, we propose a PID learning controller which consists of a set of learning rules for PID gain tuning and learning of an auxiliary input. The proposed PID learning controller is shown to drive the state of uncertain DC motor system with unknown system parameters and external load torque to the desired one world wide asymptotically. Computer simulation and experimental results are given to demonstrate the effectiveness of the proposed PID learning controller, thereby showing its superiority to the conventional fixed PID controller.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1726-1731
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• 2003

The firewall is generally used to protect the internal information system from intruders and hackers who attack through the Internet. However, it is very difficult for a user to verify the performance of the firewall as well as the difference of the performance for the operating mode such as Bridge Mode and Gateway Mode. In this paper, the performance of a firewall on the operating systems or windows 2000, Linux, and FreeBSD is compared. Finally, The performance of a firewall on the FreeBSD is compared at different operating modes and the effect of the number of rules by testing throughput of a firewall is analyzed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.258-264
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• 2015

This research suggests critical factors affecting success and failure of several commercial mobile operating systems from Palm OS appearing in to main mobile OSs appearing in 2013. For this, we analyses several mobile operating cases, elicit factors affecting success and failure of mobile OS, and conduct ID3 based inductive learning analyses based on elicited factors and values in case dataset. Through this, we draw rules in success and failure of mobile OS and suggest strategic implications for the commercial success of mobile OS in perspective of innovation and globalization.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.2
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• pp.135-142
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• 2019

Ice accretions on the ship equipment and areas are the most common issues for vessels operating in cold climate and ice-covered waters and it has effect on the vessel safety and operability of equipment and systems, thus ship machineries and structures exposed to low temperature environments should satisfy the winterization requirements specified in ice class rules. The main objective of this study is to review the state-of-the-art of winterization trend for vessels navigating in ice-covered waters. The hazard of icing and how ice accretions affect operations and safety are investigated firstly, and then winterized notations for each classification are summarized. In addition, winterization methods currently used in vessels operating in ice-covered waters are investigated for a better understanding of effective approach and its application. This information will provide a framework for future winterization issues to mitigate the ice accretion phenomena.

• Journal of Korea Water Resources Association
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• v.33 no.5
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• pp.593-601
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• 2000

Analyzing monthly inflows of the Chung-Ju Dam associated with EI Nino Southern Oscillation (ENSO), Kim and Lee(2000) reported that the fall and winter inflows in EI Nino years tended to be low while those in La Nina years tended to be high. This study proposes a methodology of employing such a teleconnection between ENSO and inflow in reservoir operations. The ENSO information is used as a hydrologic state variable in stochastic dynamic programming (SDP) to derive a monthly optimal rule for operating the Chung- Ju Dam. An alternative operating rule is also derived with the SDP with no hydrologic state variable. Both of the SDP operating rules are simulated and compared to examine the value of using the ENSO information in operations of the Chung-Ju Dam. The simulation results show that the operating rule using the ENSO information increases energy generation and reliability of water supply as well as reduces spill. spill.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.749-752
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• 2003

The HLA is defined by three components: (1) Rules, (2) the HLA Interface Specification, and (3) the Object Model Template(OMT). The RTI(Run-Time Infrastructure) software implements the interface specification. It provides services in a manner that is comparable to the way a distributed operating system provides services to applications. A way to test whether is suitable for a standard, and all service was implemented is tested through two phases of processes to verify the RTI which proposed in DMSO. In this paper, we discuss Level One Test Procedures and a method. Confirms whether RTI was implemented in Interface Specification according to Level One Test Procedures appropriately through a test. Develops Test Suite for every each step to test whether a correct command and the expected results are occur.

• The Journal of Information Systems
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• v.14 no.2
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• pp.55-74
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• 2005

In order to purchase a product cheaper, a lot of customers have been trying to search one or more marketplaces. Ever since the commercial use of the Internet, several types of marketplaces have been operating successfully on the Internet. Some of them are online shopping malls, auction markets, and group-buying markets. They have the price settlement mechanisms of their own. Online shopping malls where many stores are located support a customer to purchase the product that matches his/her requests such as price, function, design, and so forth. In online auction market, a customer can buy the product by making bids sequentially and competitively until a final price is reached. In online group-buying market, a customer can purchase the product by aggregating the orders from several buyers so that cheaper prices can be negotiated. The cheaper customers could purchase the same product item, the more satisfied they would be. However, it is very difficult for the customer to determine the marketplace to purchase, considering different kinds of marketplaces at the same time. Even though the purchasing price is cheapest in one marketplace, it is very difficult for customers to convince it the cheapest for all marketplaces. Therefore, rules and methods have been developed for purchase decision making in multiple marketplaces to reach the optimal purchase decision as a whole. They can maximize customer's utility and resolve the conflicts with other marketplaces through multi-agent negotiation.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.138-152
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• 2007

A communication system based on DATEX-ASN, an international communication protocol for use in COSMOS, a real-time traffic responsive signal system of Seoul, was developed in this study. Through laboratory experiments, it was identified that some additional rules were necessary for its successful application to COSMOS and thus proper complementary rules were devised. Laboratory experiments were to measure error-rates of monitoring information packet, EOC duration and operating cycle-length errors at different data transmission rates and the results of each experiment were compared each other. The results show that the DATEX-ASN protocol requires a transmission rate of at least 9,600bps which is higher than a transmission rate of 4,800bps required by NTCIP.

• Convergence Security Journal
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• v.11 no.1
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• pp.57-69
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• 2011

Many heterogeneous Intrusion Detection Systems(IDSs) based in misuse detection technique including the self-developed IDS are now operating in Defense-ESM(Enterprise Security Management System). IDS based on misuse detection may have different capability in the intrusion detection process according to the frequency and quality of its signature update. This makes the integration and collaboration with other IDSs more difficult. In this paper, with the purpose of creating the proper foundation for integration and collaboration between heterogeneous IDSs being operated in Defense-ESM, we propose an effective mechanism that can enable one IDS to propagate its new detection rules to other IDSs and receive updated rules from others. We also prove the performance of rule exchange and application possibility to defense environment through the implementation and experiment.

• Journal of Korea Water Resources Association
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• v.33 no.6
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• pp.733-744
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• 2000

Due to the randomness of reservoir inflow and supply demand it is not easy to establish an optimal reservoir operation rule. However, the operation rule can be derived by the implicit stochastic optimization approach using synthetic inflow data with some demand satisfied. In this study the optimal reservoir operation which was reasonably formulated as Linear Tracking model for maximizing the hydro-energy of seven reservoirs system in the Han river was performed by use of the optimal control theory. Here the operation model made to satisfy the 2001st year demand in the capital area inputted the synthetic inflow data generated by multi-site Markov model. Based on the regressions and statistic analyses of the optimal operation results, monthly reservoir operation rules were developed with the seasonal probabilities of the reservoir stages. The comparatively larger dams which would have more controllability such as Hwacheon, Soyanggang, and Chungju had better regressions between the storages and outflows. The effectiveness of the rules was verified by the simulation during actually operating period.period.