• The Journal of the Acoustical Society of Korea
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• 제32권4호
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• pp.361-368
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• 2013

As one way to describe the behavior of a vibrating string, analogies to a transmission line have been made based on the fact that they have oppositely travelling waves on each of them. In such analogies, a rigid end to the string has been represented as an open circuit, and the displacement of the string as the current on the transmission line. However it turns out that the rigid end corresponds to a short circuit, the displacement to the voltage by the theory of the transmission line, and it is confirmed by experiments with circuit simulations. Based on these discoveries, a transmission line based plucked string model comprising a transmission line, two piecewise linear current sources, and switches is proposed. The proposed model is validated by showing that the voltage at the arbitrarily chosen location, and the voltage calculated over an infinitesimal portion at the end of the transmission line are consistent with the displacement at the corresponding location and the force on the rigid end of the string from the well known difference form of a wave equation governing the behavior of the string with its fundamental frequency tuned to that for the proposed model, respectively. Moreover, the applicability of the proposed model to modeling string and wind instruments is presented.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제15권1호
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• pp.207-215
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• 2015

This paper proposes a solution-yielding linear time algorithm to NP-complete Sudoku, to which no polynomial time algorithm has been proposed. The proposed algorithm is performed on blocks in the descending order of the number of clues they contain. It firstly determines all numbers that could possibly occur in the blank rows and columns of each block. By deriving an intersecting value of corresponding rows and columns, it assigns the final number for each blank. When tested on the traditional $9{\times}9$ Sudoku, the proposed algorithm has succeeded in obtaining the solution through performance of 9 times, the exact number of the blocks. Test results on modified Jigsaw Sudoku (9 blocks) and Hypersudoku (13 blocks) also show its success in deriving the solutions by execuring 9 and 13 times respectively. Accordingly, this paper proves that the Sudoku problem is in fact P-problem.

• Applied Chemistry for Engineering
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• 제9권6호
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• pp.857-863
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• 1998

A simple and new experimental method for determination of lysozyme-M. lysodeikticus cell lysis reaction and lysozyme activity was suggested using Beer's law. The UV transmittance of the solution changed with the concentration of M. lysodeikticus and the relationship between the UV transmittance and M. lysodeikticus cell concentration followed Beer's Law. In addition, it was experimentally proven that the UV transmittance of the solution was not influenced by the lysozyme concentration and product of the lysis reaction. During the lysozyme-M. lysodeikticus cell lysis reaction, thus, M. lysodeikticus cell concentration in the solution could be measured in-situ by UV-spectrophotometer. By using these experimental data, kinetic Parameters of the Michaelis-Menten equation for the lysozyme-M. lysodeikticus cell 1ysis reaction was simply determined The maximum reaction rate constant ($k_3$) and Michaelis-Menten constants were $0.1734sec^{-1}$ and $9.83{\times}10^{-6}M$ respectively. The activity of the lysozyme could also be obtained with this experiment because the lysis reaction rate of the 1ysozyme depended on its activity.

• The Korean Journal of Applied Statistics
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• 제9권2호
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• pp.25-43
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• 1996

One of the main issues related to the precipitation amounts measured by the Korean raingage, Chukwookee, invented by King Sejong is the discontinuity in the time series around 1907 when the modern raingage was first used in Korea. To solve this discontinuity problem Wada(1971) reproduced the Chukwookee data but many authors questioned the validity of Wada's method. In this paper we analyze the precipitation amounts in Seoul from 1771 to 1994 using the intervention model and show that Wada's method results in the overestimation of the precipitation amounts. We also propose a reproduction method by considering monthly constant and including the rainfall of less then 2 mm and the snowfall which were ignored previously.

• Journal of Biomedical Engineering Research
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• 제19권1호
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• pp.53-58
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• 1998

This study examined the distribution of bone mineral density(BMD) and the von Mises stress in the patella. The BMD of eighteen patellae were determined by using quantitative computed tomography and imaging analysis software. It was found that the BMD of the patella varied with location. BMD values were largest at the superior and lateral regions and decreased inferiorly and medially. This distribution appeared to correspond to the organization of trabeculae within the patella. A two-dimensional finite element analysis was performed on each patella. It was also found that the maximum von Mises stress in the patella occurred along the cortical shell on the non-articular surface. The trabecular von Mises stress existed in the posterior region of the patella. These findings demonstrated the potential for finite element studies in vivo. Further, such studies may lead to the development of custom-made, patient-specific patella prostheses.

• Journal of the Korean GEO-environmental Society
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• 제10권4호
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• pp.65-71
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• 2009

Hydraulic fracturing technology has been widely applied in the industry for the recovery of the natural resources such as gas, oil and geothermal heat from hot dry rock. During hydraulic fracturing stimulation, multiple cracks are created resulting in mechanical interaction between cracks. Such an interaction influences obtaining hydraulic fracturing key parameters (crack opening, length, and borehole net pressure). The boundary collocation method (BCM) has been proved to be very effective in considering mechanical interaction. However, for better confidence, it needs to be verified by comparison with analytical solutions such as stress intensity factors. In this paper, three cases, single fracture in remote uniaxial tension, single fracture in remote shear stress field and two arbitrary segments in an infinite plane loaded at infinity are considered. As a result, the BCM is proved to be valid technique to consider mechanical interaction between cracks and can be used to estimate the hydraulic fracturing parameters such as opening of the fracture, and so on.

• Journal of Oral Medicine and Pain
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• 제26권3호
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• pp.181-187
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• 2001

스트레스가 인체의 항상성에 영향을 미쳐 다양한 질병 및 동통을 일으킬 수 있다는 것은 선학들의 연구에 의해 증명되어 왔다. 특히 정서적으로 중요한 구강안면영역에는 스트레스와 관련된 질병 및 동통이 많이 존재하는데, 이에대한 병리적 기전은 아직 뚜렷하게 밝혀져 있지 않다. 이에 저자는 스트레스와 말초 및 중추신경과의 병리적 관계를 알아보고자, 구속스트레스하에서 구강안면영역의 감각과 운동에 중요한 역할을 하는 삼차신경의 집합체인 삼차신경절과 뇌간조직의 단백질 변화를 western blot을 통해 살펴보았다. 실험동물은 생후 8주된 Sprague-Dawley계 웅성 백서 (323-367 g/bw)를 대조군 3마리, 실험군 15마리로 배정하였고 실험군은 실험 전기간에 걸쳐 구속스트레스를 부여하였다. 실험동물의 삼차신경절과 뇌간은 희생 즉시 적출되었으며, western blot을 시행하여 다음과 같은 결론을 얻었다. 1. 삼차신경절의 모든 군에서 약 18 KDa의 단백질이 균일하게 나타났다. 2. 뇌간의 모든 군에서 약 18 KDa 단백질이 발현되었으며, 정상 대조군, 실험 즉일, 1일, 3일, 7일에서는 뚜렷한 변화가 없었으나 실험 5일군에서는 현저한 감소를 보였다. 구속스트레스에 의해 뇌간의 5일군에서 약 18 KDa의 특수한 단백질이 뚜렷이 감소된 후 7일 군에서 다시 증가되었던 것은 스트레스에 의한 뇌간세포의 반응으로 생각되며, 뇌간에서와 다르게 삼차신경절에서는 그 변화가 나타나지 않았던 것은 스트레스에 대한 조직의 반응 차이라고 생각된다. 따라서 이를 명확하게 확인하기 위해서는 향후 수종의 스트레스와 관련된 단백질 변화에 대한 추가적인 연구가 필요하리라 사료된다.

• Journal of the Korean Data and Information Science Society
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• 제20권6호
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• pp.1129-1143
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• 2009

This paper proposes a recommendation system (Association Rule System for Targeting) which considers target which is not considered by previous Logistic Regression system, and proves that the efficiency of the recommendation system is better than that of the current and previous Apriori algorithm system. Also this study shows that the click and purchasing rate of the proposed Association Rule System for Targeting is much higher than those of current Apriori algorithm system after the purchasing campaign even though the open rate of the former is lower than that of the latter. In comparison with Logistic Regression methodology, this paper proves with experimental data that the purchasing effect of the proposed system for specific items is much higher in accuracy than that of current Apriori algorithm system even though the purchasing rate of current Apriori algorithm system is higher in whole shopping malls than that of the proposed Association Rule System for Targeting.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제20권7호
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• pp.648-656
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• 2009

We perform an analysis of the characteristics of the time-reversal pulse in Rayleigh or Ricean fading channel environments. We verify it by using Monte Carlo simulation. In a time-reversal system, each antenna in the time-reversal array receives signals from the transmitter and reverse the received signal in the time axis and then resend it to the original transmitter. We assume that the channel characteristics varies very slowly and the spatial separation between the antennas is not large. Hence the signals received by each antenna are correlated. In this paper, the effect of the correlation on the time-reversed pulse is examined, which includes the spatial properties of the time-reversal pulse such as the focus size, and spatial power distribution.

• Journal of the Institute of Electronics Engineers of Korea SC
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• 제45권6호
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• pp.82-94
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• 2008

The purpose of web-sensor is to transmit the measured sensor data and the related information to remote user. Since the user exists at remote place, the sensor information must be trustworthy, and the diagnosis for sensors should be easy to handle. To make sure of these issues, IEEE 1451 for smart sensor had been presented in the past. This research proposes the smart web sensor. The proposed smart web sensor is based on IEEE 1451.0, therefore most of the sensor interfaces are able to be used, and could realize the smart sensor by using TEDS information. Also it has the user-friendly web-service by using XML so that the remote user can handle easily the every possible information related to sensor. This research presents reference model for smart web sensor, and to prove how valuable it is, web-service using gas sensor is implemented.