• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.772-778
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• 2009

By rising the interests of the railroad, It has been required the research about railroad structure. And since 2000, the study about railway bridges caused by steel box railway bridges has been only 0.2%. So I was hard to find out about steel box railway bridges. In this study, I evaluate and analyze 4 types(KTX, Saemaeul, Mugunghwa, Freight) of dynamic caused by train loading, natural frequency and damping ratio, verticality deflection and verticality acceleration, end slope deflection, impact factor for dynamic characteristics analysis. natural frequency was measured 2.45Hz~3.34Hz and damping ratio revealed for 1.26~2.84%. Maximum verticality deflection(4.86mm) was sufficiently satisfied the design criteria(30.1mm), but in the case of verticality acceleration's respond, design criteria BRDM(Bridge Design Manual) & CTRL presentation derive rail limit value 0.35g be more than value 6 time recorded, maximum was measured 0.49g in 3 kinds of train(KTX, Saemaeul, Mugunghwa), except for Freight. Survey impact factor of Experiment bridge was 0.20 which is measured when the KTX(15:04) was driving. impact factor is enough contended with design criteria 0.29 which is presented in domestic railway design criteria and thoroughly guarantee the dynamic stability.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.1
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• pp.95-100
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• 2011

The test was done on cars travelling at speeds of 20km/h, 60km/h and 100km/h, the performance testing mode for chassis dynamometer. In this test, the secondary waveform were measured, including those using faulty MAP sensors, oxygen sensors and spark plugs. The results from these measurements and their analysis of secondary waveform can be summarized as follows: 1) The secondary waveform measured from the faulty oxygen sensor showed a lot of noise around peak voltage and in the rising and falling sections during spark line which means that the air fuel mixture was non-homogeneous. 2) The secondary waveform from the faulty MAP sensor showed the worst shape compared to other sensors, including variation of spark line, state of air-fuel mixture and velocity of flame front. 3) The spark line time of secondary waveform using a faulty spark plug displayed the shortest and smallest energy spark line, which means that a misfire occurred.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.509-513
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• 2020

Network marketing in Indonesia, especially in a time of crisis, is massively rising and has become a popular opportunity among other industries. Network marketing organizations, consists of partnership and trust, a community of connections and contact between individuals. This article has tried to examine the potential strategy to mitigate low trust in network marketing organizations specifically in the Indonesia market, where no studies on the subject has been done before. In doing this research assignment employed a secondary research methodology by reviewing previous academic literatures, by exploration and evaluation. For the purpose, 6 main articles and 25 relevant supporting articles were selected, there is an interesting and prominent research in an effort to repair trust in the perspective of the organization's efforts to build trust and control trust framework in strategy trust repair. The result of this analysis showed that the application of trust-building activities studies reveals how trust-building behavior is related to controls and how the efforts towards fostering subordinate cooperation are motivated by different types of controls and display of trustworthiness. It can be concluded that by implementing this trust repair model consistently and with a full commitment, it can gradually restore people's trust in the network marketing industry, sustain industry existence and exalted purpose of this industry can be achieved.

• English Language & Literature Teaching
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• no.1
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• pp.1-20
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• 1995

Nowadays in Korea the subject of English education has been rising as one of the essential matters which need to be emphasized, reorganized, and thus refined. From the history of about one century to the current, English education may be compared to an adolescent who should be paid much more attention to grow as an independent adult. Although we recognize that there was much improvement in the past age of English education, a lot of assignments to solve await us. This study aims to suggest a recipe for optimal learning in English classes by linking theory with practice: First, the nation-wide academic associations of English teaching should act more energetically and cooperatively than ever. They need further specialization, dynamic participation, and systematic organization. At the same time the academic journals of their own should be publicized broadly, internationally as well as nationally. Second, there should be close contact and discussion between professors and secondary-school teachers. To achieve better learning in English classes, an effective cycle of equilibrium ought to be maintained by combining theory with practice. For example, language institute in universities/colleges can serve instructional programs such as lectures, colloquiums, and intensive courses for conversation. Third, native speakers of English should be positively utilized. Teachers had better keep close contact with native speakers as frequently as possible if they want to become fluent or at least acceptable speakers in English. Teachers may also use native speakers as aides in their classes.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.12 s.354
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• pp.89-101
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• 2006

Frequency-variant transmission line parameters are determined. Then the signal transient characterizations of frequency-dependent multi-coupled lines are investigated. With the proposed method, an accurate signal integrity degradation such as signal ringing (overshoot, undershoot) and crosstalk noises relevant to the switching patterns of signals, rising / falling time(tr, tf) and line lengths is investigated. It is shown that there may be approximately 26% discrepancy of signal transients and 260% difference of crosstalk noises between the constant RLC model and frequency-variant RLC model in on-chip global interconnects while those of package lines are 11% and 70%, respectively.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.4
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• pp.405-411
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• 2012

This paper deals with direct torque control of an induction motor (IM) with constant switching frequency. The desired torque is obtained from the speed controller which is designed using the IP controller. Decoupling control of torque and flux is developed based on the energy model of IM using the IP controller strategies. The desired d-axis and q-axis stator voltage components are obtained from the designed controller, which decouples torque and flux. The constant switching frequency can be applied using space-vector pulse width modulation, since the desired stator voltage can be known from the decoupling torque and flux controllers. In order to achieve stable operation of the proposed IP controllers, the gains of the controllers are chosen by setting the poles in negative (left) half of s-plane and by choosing the rising time for the response of the step function. The proposed controller was verified in simulations using Matlab/Simulink and results have proven excellent performance. It was found that the proposed IP controllers can provide excellent performance to track the desired torque and speed and to reject the disturbance of load.

• Journal of the Society of Disaster Information
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• v.3 no.2
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• pp.95-117
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• 2007

With rapid changes taking place in every field, the expansion and specialization of various social service activities are one of the characteristics of the modem society. However, the increase of crimes and inefficiency of public police service to cope with this situation have caused discontent and distrust on the service among the public, making people more inclined to solve safety-related problems by themselves. Private Security Service(PSS) and Private Investigation Service(PIS) were introduced to satisfy these needs. In the area of PIS, Public Investigation Service System(PISS) has been established for a quite long time in foreign countries. However in Korea, PIS is being provided by unregulated service providers such as errand service center due to the lack of legal system, causing many problems related with illegal practices by the service providers. This paper is the result of the research on how to adopt a relevant PISS in Korea and develop it in the future. This kind of research is much needed to curb the rising illegal practices of the errand service centers, complement the insufficient operation of public police service, and strengthen the competitiveness of our country by taking more efficient actions in the changing public security environment. Based on the research, this paper also examines positively the possibility of introduction of PIS in Korea. This paper also recommends a prompt enactment of PIS regulation and improvement on the legal environment for such introduction of the relevant and suitable PISS in Korea.

• Journal of Astronomy and Space Sciences
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• v.32 no.4
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• pp.317-325
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• 2015

Energy spectra of electron microbursts from 170 keV to 340 keV have been measured by the solid-state detectors aboard the low-altitude (680 km) polar-orbiting Korean STSAT-1 (Science and Technology SATellite). These measurements have revealed two important characteristics unique to the microbursts: (1) They are produced by a fast-loss cone-filling process in which the interaction time for pitch-angle scattering is less than 50 ms and (2) The e-folding energy of the perpendicular component is larger than that of the parallel component, and the loss cone is not completely filled by electrons. To understand how wave-particle interactions could generate microbursts, we performed a test particle simulation and investigated how the waves scattered electron pitch angles within the timescale required for microburst precipitation. The application of rising-frequency whistler-mode waves to electrons of different energies moving in a dipole magnetic field showed that chorus magnetic wave fields, rather than electric fields, were the main cause of microburst events, which implied that microbursts could be produced by a quasi-adiabatic process. In addition, the simulation results showed that high-energy electrons could resonate with chorus waves at high magnetic latitudes where the loss cone was larger, which might explain the decreased e-folding energy of precipitated microbursts compared to that of trapped electrons.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.291-294
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• 2007

Countries in the world are setting up policies to implement anti-global warning measures to actively cope with the Agreement on Climate Change. Rising problems related to energy and environment prompted research and development efforts to highly efficient electric instrument and environmentally friendly products to secure resources and save energy Korea's high dependency on imported energy and its lack in natural resources make it urgently necessary to develop energy efficient instrument and equipment that can save energy. Every household now uses a transformer, which is very important instrument among others. A variety of technologies to manufacture transformers are currently used along with efforts to develop new materials. Development nit of high efficient transformers is called for by the time and has direct economic impact on suppliers and consumers. In addition, it is desirable to install a transformer that is trustworthy, secure, low on loss, anti-incident capable, small, anti-flammable, environmentally friendly, cost-efficient high-frequency resistant and easy for maintenance. To do this, it is necessary to look deeper into a highly efficient transformer that can save energy. This paper will discuss the types and characteristics of various transformers and propose ways to save energy and raise efficiency tv analyzing a environmentally friendly amorphous transformer.

• Journal of The Korean Society of Clinical Toxicology
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• v.6 no.1
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• pp.37-41
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• 2008

Methemoglobinemia can be caused by dapsone toxicity. We report a case dapsone induced methemoglobinemia unresponsive to methylene blue successfully treated by exchange transfusion. A 52-year-old male ingested a handful of dapsone. He presented with severe peripheral cyanosis in lips and fingertips and his methemoglobin level was found to be 21.9%. After admission, methylene blue (1%) at 1 mg/kg was injected each time peripheral cyanosis and rising serum methemoglobin occurred. Despite methylene blue therapy, the patient‘s methemoglobin level continued to fluctuate. Five days after the injections of methylene blue, many Heinz bodies were visualized in the peripheral blood, suggestive of hemolytic anemia occurrence. By hospital day 6, serum methemoglobine levels were elevated and not measurable (> 50%) and the patient was constantly in a semi-comatose mental state. An exchange transfusion carried out by utilizing 6 units of packed red blood cells and 4 units of fresh frozen plasma was performed. The patient's methemoglobin levels were subsequently kept up below 20% and his peripheral cyanosis receded. Physicians should recognize the important role of exchange transfusion in refractory dapsoneinduced methemoglobinemia.