• Human Ecology Research
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• v.56 no.3
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• pp.247-262
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• 2018

This study investigates the process of PCK formation for 2017 novice teachers in Busan. This study was conducted parallel to quantitative research using the H-PCK measurement tool as well as qualitative research methods through an open questionnaire and after-interview. Consequently, the H-PCK level of novice teachers was 3.51. The knowledge of perspective on home economics education (KP) was 3.87, knowledge of home economics curriculum (KC) was 3.37 and the knowledge of home economics instructional strategies (KI) was 3.39. Study participants reported that curriculum knowledge, curriculum content knowledge, and teaching strategy knowledge were formed through preparation for appointment; however, it was not possible to judge if PCK was formed for the restructuring ability or the reconstruction ability. Knowledge related to curriculum content was learned through teacher training, internet teacher community, and internet information materials. Knowledge of teaching strategies was learned through 1-2 teaching consulting or peer scholarship. It is necessary to revise the university curriculum (such as expansion of curriculum education, expansion of experience in teaching practice, and actual case study) order to form PCK. Second, it should be developed and operated various training programs for the formation of home economics education curriculum knowledge. Third, it is necessary to organize a nationwide system to support the mentor. In the future, it is necessary to study PCK analysis for each unit and topic as well as to explain methods that can be provided to field teachers.

• Journal of Society of Preventive Korean Medicine
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• v.6 no.2
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• pp.36-47
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• 2002

Over thousands of years oriental traditional medicine has developed a theoretical and practical approach to treat and prevent diseases and to promote people's health in China and Korea. In China, the integration of traditional Chinese medicine into the national healthcare system began in the late 1950s. This was in response to national planning needs to provide comprehensive healthcare services. On contrary to China, South Korea established the parallel operation of two independent medical systems in 1952. Hence there has been a political conflict between oriental and modern medicine over issues of fee, the ability to sell and prescribe herbal medicines, and the licensing of practitioners in traditional medicines. Given this background. This study is to compare peoples' attitudes and opinions for oriental traditional medicine by ethnicity (Chinese, Korean-Chinese and Korean). Chinese and Korean-Chinese were more used and satisfied with traditional medicine treatment and traditional practitioners compared with Koreans. The proportion of Koreans who reported the cost of traditional treatments was expensive was higher than those of Chinese and Korean Chinese. Most of Chinese, Korean-Chinese, and Koreans reported that they would use traditional medicine: 1) when they would have some disease to be treated best through traditional medicine; and 2) when traditional practitioner had a reputation and lots of experiences for those diseases. Most Korean people reported that oriental and western practitioners should cooperate each other to improve the quality of care. Therefore, policy framework including integration of traditional and western medicine, regulation, etc. is needed. In addition, research is needed to determine which diseases is treated best through traditional medicine.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2000-2006
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• 2011

Asynchronous phenomenon occurs on the synchronous generators under power system when a generator's amplitude of electromagnetic force, phase angle, frequency and waveform etc become different from those of other synchronous generators which can follow instantly varying speed of turbine. Because the amplitude of electromagnetic force, phase frequency and waveform differ from those of other generators with which are to be put into parallel operation due to the change of excitation condition for load sharing and the sharing load change, if reactive current in the internal circuit circulates among generators, the efficiency varies and the stator winding of generators are overheated by resistance loss. Where calculation method of protection settings and Logic for Protection of Generator Asynchronization will be recommended, A distance relay scheme is commonly used for backup protection. This scheme, called a step distance protection, is comprised of 3 steps for graded zones having different operating time. As for the conventional step distance protection scheme, Zone 2 can exceed the ordinary coverage excessively in case of a transformer protection relay especially. In this case, there can be overlapped protection area from a backup protection relay and, therefore, malfunctions can occur when any fault occurs in the overlapped protection area. Distance relays and overcurrent relays are used for backup protection generally, and both relays have normally this problem, the maloperation, caused by a fault in the overlapped protection area. Corresponding to an IEEE standard, this problem can be solved with the modification of the operating time. On the other hand, in Korea, zones are modified to cope with this problem in some specific conditions. These two methods may not be obvious to handle this problem correctly because these methods, modifying the common rules, can cause another coordination problem. To overcome asynchronizing protection this paper describes an improved backup protection coordination scheme using a new Logic that will be suggested.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.35-44
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• 1998

In this paper, input LC filter design of diode rectifiers considering filter V A rating reduction has been propoesd. It consisted of an input LC parallel resonent tank whose inductor and capacitor values are se$.$ lected so that the input filter presents an infinite impedance to harmonic input ac current component. The operation of proposed input filter has been analyzed in detail under steady state conditions. Performance evaluation and related design data have been provided on Per Unit basis for the proper implementation of diode rectification system. Finally, Detailed input and output current analysis has shown that the proposed input filter yield high quality input ac current waveforms, in particular, high input power factor values and more reliabilty which reducing the V A rating of passive components as compared to the standard type LC filter.filter.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.1
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• pp.89-101
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• 2001

The purpose of this study ins to verify the characteristic location of Byungyoung Castle, physical type, inside spatial organization, and the scheme of Byungyoung Castle. The study utilizes historic literature, ancient maps related to Byungyoung Castle, topographical and cadastral maps which were published under the rule of Japanese Imperialism Castle, topographical and cadastral maps which were published under the rule of Japanese Imperialism and the topographical maps which were made recently by National Geographic Institute with various scales. The methodology of the study is to interpret the contents from the historic literature on the site map. The methodology of the study is to interpret the contents from the historic literature on the site map. The result of the study is as follows; Byungyoung Castle does duty as a defensive base for the entire country and has a specific character of location that has the dual function of a mountain fortress for national defense and of a village fortress for the town. Byungyoung Castle has four gates on four sides and has a oval shape very close to a circular form. The road construction inside the castle is composed basically of a cross shape. Byungyoung is located in the northwest area of this major road system. The private houses that lie along the north-south road are build up at the core area of the lower level and the town market built up around the south gate becomes the heart of life for the people. Schematically, it has the same pattern as regular village fortress, in that the houses for the guests and the houses for the public office are arranged to the east and the west. It is considered that there is certain functional parallel between Byungyoug Castle and Ulsan castle because there are no facilities for sacrificial rites no institutional budding.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.3-8
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• 2006

The next decade promises drastic improvements and additions to global navigation satellite systems (GNSS). Plans for GPS modernization include a civilian code measurement on the L2 frequency and a new L5 signal at 1176.45 MHz. Current speculations indicate that a fully operational constellation with these improvements could be available by 2013. Simultaneously, the Galileo Joint Undertaking is in the development and validation stages of introducing a parallel GNSS called Galileo. Galileo will also transmit freely available satellite navigation signals on three frequencies and is scheduled to be fully operational as early as 2008. In other words, a dual system receiver (e.g., GPS+GALILEO) for general users can access six civil frequencies transmitted by at least fifty eights navigation satellites in space. The advent of GALILEO and the modernization of GPS raise a lot of attention to the study of the compatibility and interoperability of the two systems. A number of performance analyses have been conducted in a global scale with respect to availability, reliability, accuracy and integrity in different simulated scenarios (such as open sky and urban canyons) for the two systems individually and when integrated. Therefore, the scope of this article aims at providing the technical benefits analysis for Taiwan specifically in terms of the performance indices mentioned above in a local scale, especially in typical urban canyon scenarios. The conclusions gained by this study will be applied by the Land Survey Bureau of Taiwanese as the guideline for developing future GNSS tracking facilities and dual GNSS processing module for precise surveying applications in static and kinematic modes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.395-400
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• 2017

The paper discussed the air-to-fuel ratio control of automotive fuel-injection systems using the cerebellar model articulation controller(CMAC) neural network. Because of the internal combustion engines and fuel-injection's dynamics is extremely nonlinear, it leads to the discontinuous of the fuel-injection and the traditional method of control based on table look up has the question of control accuracy low. The advantages about CMAC neural network are distributed storage information, parallel processing information, self-organizing and self-educated function. The unique structure of CMAC neural network and the processing method lets it have extensive application. In addition, by analyzing the output characteristics of oxygen sensor, calculating the rate of fuel-injection to maintain the air-to-fuel ratio. The CMAC may easily compensate for time delay. Experimental results proved that the way is more good than traditional for petrol control and the CMAC fuel-injection controller can keep ideal mixing ratio (A/F) for engine at any working conditions. The performance of power and economy is evidently improved.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.265-276
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• 2017

In this paper, a robust and more accurate trajectory tracking control method for a mobile robot is proposed using WIPDC(Weighted Integral Parallel Distributed Compensation) and T-S Fuzzy disturbance observer. WIPDC reduces the steady state error by adding weighted integral term to PDC. And, T-S Fuzzy disturbance observer makes it possible to estimate and cancel disturbances for a T-S fuzzy model system. As a result, the trajectory tracking controller based on T-S Fuzzy disturbance observer shows robust tracking performance. When the initial postures of a mobile robot and the reference trajectory are different, the initial control inputs to the mobile robot become too large to apply them practically. In this study, also, the problem is solved by designing an initial approach path using a path planning method which employs $B\acute{e}zier$ curve with acceleration limits. Performances of the proposed method are proved from the simulation results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.4
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• pp.468-480
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• 1993

In this paper, at first, the characteristics of double mode SAW (DMS) resonator are analysed by applying the wave guide model and coupled mode theory to 1-port resonator. The DMS resonators (2-pole), which are arranged in a close, parallel configuration of two identical 1-port resonators on a single plate, and 4-pole DMS filters are designed and fabricated at the center frequency of 150.15 MHz with 3-dB bandwidth of 80 KHz. The empirical design characteristics are obtained from the comparison of experimental and theoretical values resulted from several fabrications, and the narrow bandpass filters are implemented on the basis of the above empirical results, which can be used to mobile communication systems. A ST-cut quartz substrate is selected for the stable temperature-frequence characteristics, and high resolution photolithography is applied to the fabrication of filter to get the fine electrode patterns.

• Journal of Power Electronics
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• v.16 no.1
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• pp.297-309
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• 2016

Grid-connected inverters (GCIs) with an LCL output filter have the ability of attenuating high-frequency (HF) switching ripples. However, by using only grid-current control, the system is prone to resonances if it is not properly damped, and the current distortion is amplified significantly under highly distorted grid conditions. This paper proposes a synchronous reference frame equivalent proportional-integral (SRF-EPI) controller in the αβ stationary frame using the parallel virtual resistance-based active damping (PVR-AD) strategy for grid-interfaced distributed generation (DG) systems to suppress LCL resonance. Although both a proportional-resonant (PR) controller in the αβ stationary frame and a PI controller in the dq synchronous frame achieve zero steady-state error, the amplitude- and phase-frequency characteristics differ greatly from each other except for the reference tracking at the fundamental frequency. Therefore, an accurate SRF-EPI controller in the αβ stationary frame is established to achieve precise tracking accuracy. Moreover, the robustness, the harmonic rejection capability, and the influence of the control delay are investigated by the Nyquist stability criterion when the PVR-based AD method is adopted. Furthermore, grid voltage feed-forward and multiple PR controllers are integrated into the current loop to mitigate the current distortion introduced by the grid background distortion. In addition, the parameters design guidelines are presented to show the effectiveness of the proposed strategy. Finally, simulation and experimental results are provided to validate the feasibility of the proposed control approach.