• Proceedings of the KSR Conference
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• 2003.10c
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• pp.587-593
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• 2003

There has been much interest in the Bluetooth technology since it could enable users to connect to a wide range of computing and telecommunication devices without the need to carry or connect cables. It delivers opportunities for rapid, ad-hoc connections, and in the future, could possibly enable automatic, unconscious, connections between devices. In this paper, we discussed a scatternet formation protocol for Bluetooth-based ad hoc networks and proposed the identification system of an object using Bluetooth Scatternets. Over the past few years, several studies have been made on the identification of an object by several RF(Radio Frequency) systems. But there are still some problems, the interference of signals as an example, for the identification of an object. The critical question is how to identify an object precisely without the interference of signals. This paper is an investigation of the Scatternet formation protocol for Bluetooth-based ad hoc networks and the identification system of an object using Bluetooth Scatternets composed of multiple Piconets.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.9
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• pp.1-12
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• 1996

In this paper, we propose an adaptive gait by which a quadruped walking robot can walk against external disturbances. This adaptive gait mechanism makes it possible for a quadruped walking robot to change its gait and accommodate external disturbances form various external environmental factors. Under the assumption that external disturbances can be converted to an external force acting on the body of a quadruped walking robot, we propose a new criterion for the stability margin of a waling robot by using an effective mass center based on the zero moment point under unknown external force. And for a solution of an adaptive gait against external disturbances, an method of altitude control and reflexive direction control is suggested. An algorithmic search method for an optimal stride of the quadruped mehtod, the gait stability margin of a quadruped walking robot is optimized in changing its direction at any instance for and after the reflexive direction control. To verify the efficiency of the proposed approach, some simulaton results are provided.

• Journal of Power Electronics
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• v.14 no.3
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• pp.608-620
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• 2014

In this paper, an adaptive neural phase-locked loop (AN-PLL) based on adaptive linear neuron is proposed for grid-connected doubly fed induction generator (DFIG) synchronization. The proposed AN-PLL architecture comprises three stages, namely, the frequency of polluted and distorted grid voltages is tracked online; the grid voltages are filtered, and the voltage vector amplitude is detected; the phase angle is estimated. First, the AN-PLL architecture is implemented and applied to a real three-phase power supply. Thereafter, the performances and robustness of the new AN-PLL under voltage sag and two-phase faults are compared with those of conventional PLL. Finally, an application of the suggested AN-PLL in the grid-connected DFIG-decoupled control strategy is conducted. Experimental results prove the good performances of the new AN-PLL in grid-connected DFIG synchronization.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2170-2172
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• 2003

This paper presents the position tracking control of an inverted pendulum on an inclined railway. In general, inclining the railway leads to errors in the pendulum angle even though the pendulum is stabilized, which results in errors in the cart position. To solve this problem, a linear quadratic regulation (LQR) controller with an integrator is used for compensating the resulting error in the cart position. The proposed method is evaluated by comparing LQR controllers with and without an integrator. Experimental results show that the LQR controller with an integrator is better in performance than one without an integrator.

• The Transactions of the Korea Information Processing Society
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• v.3 no.3
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• pp.672-682
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• 1996

In this paper, we propose an algorithm to transform an object calculus into an object algebra. The algorithm translates the calculus expression into an equivalent algebra expression, and it maps the object algebra expression to an object algebra operator graph. This translation algorithm not only generates an efficient access plan of queries, but also proves the equivalent expressiveness of queries.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.161-168
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• 1998

This paper presents an simulation methdology for determining an economical running pattern for a high speed train which minimizes energy consumption under an given trip time margin. The economical running pattern is defined with an economical maximum speed in traction phase, a speed at the end of coasting and a speed at the end of regenerative braking alone in braking phase. An economical run for subways is also described. As a case study, the simulation is carried out fer an economical run of high speed NamSeoul-Pusan line, and the results described. To do this, train performance simulation program is built and extended to be able to find an economical running pattern and then to simulate the defined economical run.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.2
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• pp.559-562
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• 2012

Serum alpha-fetoprotein (AFP) is a significant marker for clinical diagnosis and prognosis evaluation in hepatocellular carcinoma (HCC) patients. However, some proportion of liver cancer patients are AFP-negative (AFP ${\leq}$20ng/ml). In order to study the differences between clinicopathological factors and prognosis of alpha-fetoprotein negative and positive patients, a total of 114 cases (41 AFP-negative and 73 AFP-positive) were selected for our research. By systematically statistical analysis, the results demonstrated that compared with AFP-negative patients, AFP-positive examples were more likely to feature cirrhosis nodules, non-complete neoplasm capsules, and a poor Edmondson-steiner grade. Furthermore, AFP-negative patients demonstrated a favorable long-term prognosis. By univariate analysis and multivariate analysis with Cox's proportional hazards model, multiple tumors were found to be independent risk factors for worse survival of AFP negative patients; however, less tumor-free margins, multiple tumors and Edmondson-steiner grades III/IV, proved to be independent risk factors leading to a poor prognosis of AFP positive cases. Finally, we can infer that high levels of AFP signify a highly malignant tumor and unfavorable prognosis.

• 한국약용작물학회:학술대회논문집
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• 2007.11a
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• pp.302.2-302.2
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• 2007

• Kyungpook Mathematical Journal
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• v.45 no.4
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• pp.603-607
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• 2005

We give an integral representation for an analogous continued fraction of Ramanujan, for this we first prove an interesting identity.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2019.05a
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• pp.289-290
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• 2019