• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.673-676
• /
• 2005

In this paper, we proposed the electric circuit using one common arm of H-Bridge Inverters to reduce the number of switching component in multi-level inverter combined with H-Bridge Inverters and Transformers. and furthermore we suggested the new multi-level PWM inverter using PWM level to reduce THD(Total Harmonic Distortion). and we used the switching method that can be same rate of usage at each transformer. Also, we tested the proposed prototype 9-level inverter to clarify the proposed electric circuit and reasonableness of control signal for the proposed multi-level PWM inverter.

• Korean Journal of Agricultural Science
• /
• v.29 no.1
• /
• pp.84-98
• /
• 2002

Rank of Chungnam's flower industry in Korea is sixth in the number of flower fanning household and fifth in the flower cultivating land size in 2000. However, based on the SWOT analysis of Chungnam's agro-environmental factors influencing flower growing, it is noted that further shift of the regional flower industry up to 2nd highest rank nationally can be demonstrated. Strategies for achieving such targets are suggested as follows ; 1) specializing in flower varieties with regional comparative advantage, such as orchids, lily and rose, 2) establishing the educational system for farmers to manage the risks of market price fluctuation, flower cultivation and agricultural finance properly, 3) enlarging the investments in R&D and research facilities 4) assigning the efficient function and communication among the local government, farmers and agricultural marketeers so as to increase the flower exportation.

• Journal of information and communication convergence engineering
• /
• v.13 no.2
• /
• pp.69-73
• /
• 2015

We focus on a sounding signal design for single-input single-output orthogonal frequency division multiplexing (SISO-OFDM) systems. We show that the frequency spectrum of an optimum sounding signal has a constant magnitude across the frequency band for the cases with or without Doppler effects. Simulation results show that the designed optimum sounding signal outperforms random sounding signals and that the performance of a maximal-length shift register sequence is indistinguishable from that of the optimum sounding signal.

• Proceedings of the KIEE Conference
• /
• 2009.04b
• /
• pp.152-155
• /
• 2009

In high power application, PFC(Power Factor Correction) pre-regulators are generally required. PFC pre-regulators could achieve unity power factor, reduce line input current harmonics and utilize full line power. Interleaving PFC converters could reduce input ripple current, output capacitor ripple current and inductor size. With this closed loop interleaving method, both two phase converters are working at the boundary between continuous and discontinuous mode and accurate 180 degree phase shift is achieved. Implementation of this strategy could be easily integrated to the control chip. Finally, experimental results of a two-phase interleaved boost PFC are presented to verify the discussed features.

• Journal of Distribution Science
• /
• v.8 no.1
• /
• pp.5-11
• /
• 2010

This study addresses a shift, generally positive, in the acceptance and adoption of mobile commerce. The study, based on data collected using a survey questionnaire from mobile phone users in South Korea, examined the relationships using factor analysis and multiple regression analysis methods. The results showed equal positive adoption rates across all demographics of age, education, and income, except for gender, in terms of attitudes toward mobile shopping. The rate of mobile commerce adoption was relatively stronger among females than males. This finding provides new developments to mobile service providers on the effect of demographic profile on consumers'behavior and attitudes toward mobile shopping. Based on the results of the study, practical implications for marketing strategies in mobile commerce markets are suggested.

• Journal of Contemporary Eastern Asia
• /
• v.19 no.2
• /
• pp.169-178
• /
• 2020

Thomas L. Friedman's "Our New Historic Divide: B.C. and A.C. ― The World Before Corona and the World After" column is becoming the talk of the times. Whoever talks about the post-Corona world mentions "BC/AC" as a new concept. However, people seem to be overusing the term "BC/AC" while overlooking the specific context that Friedman emphasized. So, taking into account the cultural differences and contexts of the East and the West highlighted in Friedman's column, we devised the "BC/AC" ten-paradigm hypothesis. We hope these ten cultural shifts will be the first step in examining the post-Corona world.

• Journal of Information Technology Applications and Management
• /
• v.29 no.6
• /
• pp.63-80
• /
• 2022

In this paper, we study structural changes and performance gains in condition-based maintenance process redesign when mobile IoT technology is embedded into urban railway rolling stock. We first develop condition-based maintenance To-Be process model in accordance with the IoT deployment scheme. Secondly, we draw upon theoretical framework of redesign process analysis to develop performance evaluation method suitable to predictive maintenance shift from As-Is ordinary maintenance practice. Subsequently, To-Be process performance evaluations are conducted adopting both the quantitative and qualitative method for time, cost, and dependability dimensions. The results ascertain the considerable benefits captured through detection abnormality prior to actual rolling stock failure occurrence, and details of performance improvements and enhancement of standardization level is revealed. The procedures and results presented in this paper offers useful insights in the fields of IoT economic analysis, condition based maintenance, and business process redesign.

• International journal of advanced smart convergence
• /
• v.13 no.1
• /
• pp.122-128
• /
• 2024

This study delves into the unique transformation of South Korea's elderly population, distinctively termed 'Nomad Silver'. Characterized by individuals aged 65 and above who actively seek novel experiences and embrace new activities, this demographic shift signifies a departure from traditional perceptions of the elderly. The Nomad Silver cohort, distinguished by their significant economic influence and evolving needs, necessitates a tailored approach to healthcare services. This paper underscores the importance of comprehending both the fundamental biological needs and the personalized desires of the Nomad Silver, aiming to enhance their satisfaction and overall well-being. Hospitals, in response, should innovate their services to resonate with the emotional, psychological, and social facets of this age group. Consequently, the paper proposes a four-pronged strategy for hospitals to adapt: comprehensive healthcare provision, patient-centric service development, senior health education coupled with community engagement, and establishing a generational bridge hub. Furthermore, the paper posits that catering to the Nomad Silver not only promises substantial financial gains for hospitals but also fosters new business opportunities across various sectors.

• Convergence Security Journal
• /
• v.14 no.3_1
• /
• pp.21-26
• /
• 2014

Sports paradigm shift gave an opportunity to transform into production-oriented industry activities creating high value-added. Sports industrial cluster, organic union of qualitative industries producing and distributing of various sports derivative products, is necessary system in these sports paradigm shift. This study is intended to suggest the definition, construction, and direction for future of sports industrial cluster. In order to ensure the sustainable growth of sports industrial cluster, a growth strategy such as switching to the sementic cluster is needed. And the direction for future of sports industrial cluster were as following; finding the growth engine sports industry field according to the convergence, systematically promoting by setting the medium and long term development goals, constructing a wide industrial region for global competitiveness of sports industry.

• Journal of Korean Neurosurgical Society
• /
• v.59 no.6
• /
• pp.628-636
• /
• 2016

Objective : Chronic subdural hematoma (cSDH) is common condition in neurosurgical field. It is difficult to select the treatment modality between the surgical method and the conservative method when patients have no or mild symptoms. The purpose of this study is to provide a suggestion that the patients could be cured with conservative treatment modality. Methods : We enrolled 16 patients who had received conservative treatment for cSDH without special medications which could affect hematoma resolution such as mannitol, steroids, tranexamic acid and angiotensin converting enzyme inhibitors. The patients were classified according to the Markwalder's Grading Scale. Results : Among these 16 patients, 13 (81.3%) patients showed spontaneously resolved cSDH and 3 (18.7%) patients received surgery due to symptom aggravation and growing hematoma. They were categorized into two groups based on whether they were cured with conservative treatment or not. The first group was the spontaneous resolution group. The second group was the progression-surgery group. The mean hematoma volume in the spontaneous resolution group was 43.1 mL. The mean degree of midline shift in the spontaneous resolution group was 5.3 mm. The mean hematoma volume in the progression-surgery group was 62.0 mL. The mean degree of midline shift in the second group was 6 mm. Conclusion : We suggest that the treatment modality should be determined according to the patient's symptoms and clinical condition and close observation could be performed in patients who do not have any symptoms or in patients who have mild to moderate headache without neurological deterioration.