• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.5
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• pp.538-542
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• 2018

Echo generated in digital hearing aid vent give rise to user's discomfort. For cancelling feedback echo in vent, it is required to estimate vent impulse response exactly. The vent impulse response has time varying and sparse characteristics. The IPNLMS has been known a useful adaptive algorithm to estimate vent impulse response with these characteristics. In this paper, subband sparse adaptive filter which applying IPNLMS to subband hearing aid structure is proposed to cancel echo of vent by estimating sparse vent impulse response. In the propose method, the decomposition of input signal to subband can pre-whiten each subband signal, so adaptive filter convergence speed can be improved. And the poly phase component decomposition of adaptive filter increases sparsity of each components, and the better echo cancellation can be possible without additional computation. To derive coefficients update equation of the adaptive filter, by defining the cost function based weight NLMS is defined, and the coefficient update equation of each subband is derived. For verifying performances of the adaptive filter, convergence speed, and steady state error by white signal input, and echo cancelling results by real speech input are evaluated by comparing conventional adaptive filters.

• 대한공업교육학회지
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• v.45 no.1
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• pp.84-102
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• 2020

During the period of rapid industrial growth, specialized high schools were important vocational education institutions trained specialists and technicians. But now, specialized high schools turned into high schools where the low-ranking students who were pushed out of the competition for admission due to a decline in the education population, changes mostly in labor demand in the labor market, and discrimination against skilled workers. In order to solve this problem, the middle school 3rd grade teachers in charge of the middle school can provide early career guidance, so that they can decide to go to the specialized high school according to their aptitude and talent rather than their grades. The purpose of this study is to investigate the relationship between general characteristics and perception of middle school 3rd grade teachers, and the rate of decision to enter specialized high school. In 2018, The middle school 3rd grade teachers in charge in Daejeon metropolitan city were selected. The results of this study were as follows: When 3rd grade teachers in charge are the male teachers 21.01%(M=.2101) of their students go to specialized high schools. When they are teachers who have not graduated from college of education(M=.2110), with doctoral degree(M=0.3064), of their students go to specialized hight schools. Finally, there was a significant positive relationship between perceptions of high school teachers (β1 = .245, p = .000) and high school graduates (β2 = .149, p = .027). The regression equation derived from this is y = -0.56 + 0.037 * β1 + 0.025 * β2 10.1% (R² = 0.101).

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.1
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• pp.1-10
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• 2011

This study was performed for the purpose of reviewing the strategic management direction and ideas of the policy for Seoul City's Hangang Renaissance. In order to accomplish this, levels were established for each step of the policy and the policy priority by level was derived. The policy priority by level was analyzed by a decision making model through the Analytic Network Process(ANP) and the priority would be the standard to judge the order of priority. The analysis results showed that there was not a big difference between the priorities of two basic concepts: restoration and creation. The fourth level, detail plan of the third level, showed priority that development by type for waterside city in case of reorganizing city space and diversification of land utilization, utilization of riverside space in water front town for public and composit purpose, establishment of comprehensive plan on constructions in case of improving the landscape of Hangang and unified design plan rose to important element in case of forming Hangang park with the me. Based on the results of priority analysis, we would like to propose for the direction about the policy on Hangang Renaissance project, the policies forming Hangang Park with theme through unified design plan and reorganizing city space have to be proceed preferentially and connected with other plans.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.2
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• pp.11-22
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• 2017

To successfully create a low-carbon landscape in order to become a low-carbon city, it is necessary to understand the dynamics of artificial greening's resources on a multi-scale. Additionally, the effects of carbon storage should be quantitatively evaluated. The purpose of this study is to simulate and evaluate the changes in carbon storages of artificial ground trees using system dynamics throughout a long-term period. The process consisted of analyzing the dynamics of the multi-scale carbon cycle by using a casual loop diagram as well as simulating carbon storage changes in the green roof of the Gangnam-gu office building in 2008, 2018, 2028, and 2038. Results of the study are as follows. First, the causal loop diagram representing the relationship between the carbon storage of the artificial ground trees and the urban carbon cycle demonstrates that the carbon storage of the trees possess mutual cross-scale dynamics. Second, the main variables for the simulation model collected 'Biomass,' 'Carbon storage,' 'Dead organic matter,' and 'Carbon absorption,'and validated a high coefficient of determination, the value being ($R^2$=0.725, p<0.05). Third, as a result of the simulation model, we found that the variation in ranking of tree species was changing over time. This study also suggested the specific species of tree-such as Acer palmatum var. amoenum, Pinus densiflora, and Betula platyphylla-are used to improve the carbon storage in the green roof of the Gangnam-gu office building. This study can help contribute to developing quantitative and scientific criteria when designing, managing, and developing programs on low-carbon landscapes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.637-644
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• 2004

This paper proposed and implemented the adaptive transmission middleware for video streaming, which is able to support the adaptive transmission of video data to the fluctuating changes of network environment in the packet-based network and the properties of transmitted video data. The adaptive transmission middleware is made up SR-RTP-based transfer module and TFRC(TCP Friendly Rate Control)-based transfer-rate control module. The SR-RTP-based transfer module supports RTP-based real-time transfer of video data and packet retransmission scheme retransmitting the high-priority packets selectively in the damaged video data to reduce the error induced by the packet loss. Sharing the transmission bandwidth of network with the TCP-based data transfer, the TFRC-based transfer-rate control module controls the transfer rate of video data according to the most allowable transmission bandwidth in the network, so that the transfer rate is controlled adaptively to the fluctuating changes of transmission bandwidth. This paper, for the experiment, applied the adaptive transmission middleware to video streaming in the external Internet environment, and analyzed the effective frame transfer rate and the degree of the streaming jitter to evaluate the performance of packet-loss recovery and adaptive transfer rate control. In the external Internet environment where the packet-loss rate is high a bit, the relatively high streaming performance was showed compared with the case that didn't apply the adaptive transmission middleware.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.506-510
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• 2004

A torque transmission system composed of several gears and couplings is flexible. In order to get an exact response of motor, the torsional vibration due to an unexpected change of motor speed must be suppressed. Therefore, it is very important that motor control suppress vibration. Various methods to control it including dual inertia system are proposed. Specially, the method of vibration suppression is that vibration can be suppressed to fee㏈ack the estimated torsion torque via the disturbance observer filter being of normal filter. The suitable Proportional controller and coefficient parameter can be designed using CDM and the torsional vibration also be suppressed, but it has a low degree of adaptability to disturbance. The PID controller can be designed easily, but makes the excessive overshoot and oscillation for system response in the early period. To resolve these problems, simple and practical PID controller with two degree of freedom is proposed recently that it ran improve performance of obeying the reference unconcerned in any disturbance by changing the proportional gain by two degree of freedom parameter. But it has also the defect that parameter a must be changed to obtain the ideal Proportional parameter. On this paper, we design the controller which automatically adjusts parameter u using fuzzy Algorithm to overcome such defects. Also, we compare the proposed method with established one and evaluate them to confirm performance of the designed controller.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.452-455
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• 2009

The Nakdong Delta can be identified by two different geomorphic units. The first one is the upper delta. This is mostly composed of inter-distributary islands that are largely influenced by fluvial processes and attributed to the development of these islands along the river. The other one is the lower delta which is mostly composed of beach ridges. Barrier islands are largely effected by wave processes promoted by the development almost at a right angle to the river. Influenced by the longshore current which flows to the same direction, barrier islands located in the Nakdong river estuary are developing from east to west direction. As a result, the eastern end of the barrier islands are growing toward the north-west direction effected by tidal current which moves toward the same direction. Barrier islands include the Sinho Island, the Jinwoo Island, the Daema deung, the Janga Island, the Baghap deung, the Sae deung, and the Chulsae deung(Doyeo deung). They have orderly emerged from the sea since 1861. Since 2008, a new Deung, a sand dune growing under sea, has been developing rapidly from Chulsae deung to the Dadaepo beach. It made the sailing of small fisher boats impossible. Tidal currents transported a lot of sand and silt around the barrier islands. The landscape of Nakdong river estuary where many barrier islands are distributed will change rapidly affecting land environment.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.627-635
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• 2013

This study examines the issue of causality between ocean industries and urban economic growth in the sea port city. To maximize economic advantage of Busan as a sea port city, we first need to analyze the effects of ocean industries on urban economic growth. This study focuses on the examination of the role of ocean industries and its related variations in economic growth at the urban level. Using data from Busan. Metropolitan City in Korea during 1985-2011, we find that the causality link between ocean industries and urban economic growth rates runs in both directions. Especially, industries of shipping/port, marine tourism, and shipbuilding were the most important variables in Busan economy. With this information, the empirical results show that ocean industries and its related variations have significant effects on urban economic growth. Based on these significant research findings, theoretical and practical implications were discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.522-529
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• 2016

This study examined the effects of 4-weeks of backward walking exercise on ROM, VAS (Visual Analogue Scale) score and proprioception in anterior cruciate reconstruction patients. Fourteen subjects were randomly assigned to either a backward walking group (BWG, n=7) or a control group (CON, n=7) and then participated in rehabilitation program for 4 weeks. The ROM of the flexion significantly decreased in both groups (BWG, p<0.001 vs CON, p<0.01), while ROM of extension significantly decreased only in the BWG (p<.05) post exercise, but no significant difference was observed between groups. Additionally, VAS score decreased significantly in both groups (P<0.001) and BWG was lower than CON post exercise (p<0.001). Finally, proprioception decreased significantly in both groups (BWG, p<0.001 vs CON, p<0.05), but did not differ significantly between groups. These results suggest that the 4 week backward walking rehabilitation program improves ROM, VAS score, and proprioception and has positive effects on functional recovery of anterior cruciate ligament reconstruction patients.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.5875-5887
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• 2015

This research aimed to investigate the relations of perfectionism and multicultural attitude upon a premise that sub-factors of the perfectionism : self-oriented perfectionism, other-oriented perfectionism and socially-prescribed perfectionism are related to multicultural attitude and to examine the moderation effect of self-acceptance on the relation between perfectionism and multicultural attitude. The questionnaires designed to measure multidimensional perfectionism, unconditional self-acceptance and multicultural attitude were administered to 258 office workers in Seoul and Gyeoggi-Do. The results from correlation analysis and regression analysis were as followed. First, sub-factors of the perfectionism was partially associated with sub-factors of multicultural attitude. In particular two sub-factors of the perfectionism : 'self-oriented perfectionism', 'other-oriented perfectionism' yielded effect on multicultural attitude, controlling the effects of other subscales. Second, unconditional self-acceptance moderated the relation between 'self oriented perfectionism' and sub-factor of the multicultural attitude : 'recognizing difference'. And unconditional self-acceptance moderated the relation between 'socially prescribed perfectionism' and sub-factors of the multicultural attitude : 'recognizing difference', 'openness and acceptance'. This present findings not only extend understandings about relationship between perfectionism and multicultural attitude by examining self-concept : unconditional self-acceptance but also provide that it isn't helpful that further support and rationale for unconditional self-acceptance as intervention for targets to focus in counseling process for those who suffer from perfectionism.