• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.578-585
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• 2012

Reciprocating engine is widely used for small propeller driven aircraft. because it is the superior efficiency and low price. Currently, reciprocating engine is used for the development of KC-100, LSA, PAV, UAV in domestic. In this study, Naturally aspirated engine and turbocharger engine performance model is developed. The propeller is designed and analyzed at cruise condition of reciprocating engine aircraft using optimum method, the propeller performance model is developed. The Integrated propulsion performance model is developed, through the matching with engine and propeller performance model, for small reciprocating engine aircraft performance analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.77-82
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• 2015

Recently, multi-user massive MIMO (MU-Massive MIMO) network has attracted a lot of attention as a technology to accommodate explosively increasing mobile data traffic. However, the MU-Massive MIMO network causes a tremendous hardware complexity in a base station and computational complexity to select optimal set of users. In this paper, we thus propose a simple algorithm for selecting antennas and users while reducing the hardware and computational complexities simultaneously. The proposed scheme has a computational complexity of $O((N-S_a+1){\times}min(S_a,K))$, which is significantly reduced compared to the complexity of optimal scheme based on Brute-Force searching, $$O\left({_N}C_S_a\sum_{i=1}^{min(S_a,K)}_KC_i\right)$$, where N, $S_a$, and K denote the number of total transmit antennas, the number of selected antennas, and the number of all users, respectively.

• Korean Journal of Ecology and Environment
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• v.45 no.1
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• pp.102-109
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• 2012

In this study, the four different filter media (sponge, volcanic stone, activated carbon and magnesium hydroxide) were tested for the removal of algae and phosphorus in the two eutrophic water samples (natural water and artificial algal culture with BG-11 medium). These filter media were used in the column device as single or combined applications. The effect of the $Mg(OH)_2$ on phosphorus removal was examined using different particle sizes (<2 mm and >2 mm) and concentrations (0, 10, 50 and 100 g $L^{-1}$) of magnesium hydroxide. The removal efficiency of phosphate by magnesium hydroxide was increased with longer experimental time and higher concentration. However, there was no significant difference in the degree of phosphorus removal between any two particle sizes (1 mg P $L^{-1}$: F=0.109, P=0.685; 10 mg P $L^{-1}$: F=1.542, P=0.355). Among the four media, activated carbon showed the most potent effect on the removal of both algae and phosphorus. The highest removal efficiency of algae and phosphorus was obtained by combining four columns of each filter medium. Interestingly, integration of four filter columns showed higher removal efficiency than activated carbon alone. The highest removal efficiency by integrated filter columns seemed to be caused by a synergistic effect of combined activated carbon and magnesium hydroxide.

• Journal of the Korean Society for information Management
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• v.38 no.2
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• pp.153-172
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• 2021

This study is to create a deep learning based classification model to examine the characteristics of panic disorder and to classify the panic disorder tendency literature by the panic disorder corpus constructed for the present study. For this purpose, 5,884 documents of the panic disorder corpus collected from social media were directly annotated based on the mental disease diagnosis manual and were classified into panic disorder-prone and non-panic-disorder documents. Then, TF-IDF scores were calculated and word co-occurrence analysis was performed to analyze the lexical characteristics of the corpus. In addition, the co-occurrence between the symptom frequency measurement and the annotated symptom was calculated to analyze the characteristics of panic disorder symptoms and the relationship between symptoms. We also conducted the performance evaluation for a deep learning based classification model. Three pre-trained models, BERT multi-lingual, KoBERT, and KcBERT, were adopted for classification model, and KcBERT showed the best performance among them. This study demonstrated that it can help early diagnosis and treatment of people suffering from related symptoms by examining the characteristics of panic disorder and expand the field of mental illness research to social media.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2704-2706
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• 2002

본 논문에서는 항문 괄약근 전용 근전도 센서(Intra-Anal Sensor)를 항문내에 삽입한 후 운동을 하면 시스템 하드웨어와 연결된 80C196KC 마이크로 콘트롤러와 프로그램에 의해서 LED Display 및 스피커 출력을 통해 괄약근 근전도 신호의 크기를 나타내 주며, 컴퓨터와 직접 연결하면 PC상의 모니터 출력을 통해 보다 손쉽게 환자의 상태를 알아볼 수 있도록 Visual C 프로그램을 사용한 윈도우 프로그램을 구현하였다.

• Journal of Nutrition and Health
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• v.52 no.5
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• pp.465-474
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• 2019

Purpose: This study examined the association between the serum 25-hydroxyvitamin D concentration and the cognitive functions in Korean elderly. Methods: The subjects were 393 adults aged 60 years or older who participated in the Yangpyeong cohort between July 2009 and August 2010. The subjects were classified into deficiency, insufficiency, or adequacy groups according to the serum 25-hydroxyvitamin D concentration diagnostic criteria suggested by the US Institute of Medicine (IOM). The cognitive function was assessed based on the Korean version of the Mini-Mental State Examination (MMSE-KC). The dietary intake was assessed using the quantitative food frequency questionnaire with 106 food items. Results: The proportions of deficiency, insufficiency, or adequacy in serum 25-hydroxyvitamin D were 6.6%, 44.5%, and 48.9%, respectively. The serum 25-hydroxyvitamin D concentration was significantly higher in men than in women and in outdoor workers than in other occupations. The adequacy group had higher MMSE-KC scores than the other two groups, but not to a significant degree. The proportion of cognitive impairment tended to decrease with increasing serum vitamin D concentration to deficiency, insufficiency, and adequacy (p for trend = 0.029). The deficiency group had a 2.28 times higher risk of cognitive impairment than the adequacy group, but the difference was not statistically significant (OR, 2.28; 95% CI, 0.18 ~ 1.07, p for trend = 0.119). Conclusion: The serum vitamin D concentration tended to be associated with the cognitive function in elderly Koreans living in rural areas. To confirm the associations, further longitudinal studies with large samples were required.

• Journal of Aerospace System Engineering
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• v.11 no.3
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• pp.31-38
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• 2017

As demand for best practices relative to flight test safety management operations and processes in the aviation industry grows, standards for such aspects of the industry in Korea should be examined. Therefore, in this paper, we conducted flight test operation processes and safety management program development studies based on documents related to flight tests of the Korean civil aviation KC-100, the military aircraft T-50, the FAA (Federal Aviation Administration), and CAAC (Civil Aviation Administration of China) for performance validation, test evaluation and safety certification for aircraft under development and remodeling. In addition, we introduced and analyzed best practices of the FTSC (Flight Test Safety Committee) applicable to aircraft flight test processes.

• Journal of the Korean Society for Library and Information Science
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• v.40 no.3
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• pp.151-173
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• 2006

The purpose of this study is to make out a draft for the standard classification of the National Knowledge and Information Resources. As the result of the Study the standard classification system of the national knowledge and information resources, named "Knowledge Classification 'KC' is suggested. KC consists of 3 classification systems classification by subject, type of resources and type of media. The classification by subject has 12 main classes, and each main class has divisions. Main classes consist each of major discipline or group of related disciplines. The type of resources is classified by 10 types of content, likewise numbered 0-9, and the media of knowledge are classified by 8 types. likewise 0-7. In the Practice the notation always consists of 2 characters and 2 digits. The first character designate main class and the second character designate division. The first number designate the type of resources and the second number designate the type of media.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.4
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• pp.311-318
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• 2004

Generally, PM BLDC drive system is necessary that the three Hall-ICs evenly be distributed around the stator circumference and encoder installed in case of the 3 phase motor. The Hall-ICs are set up in this motor to detect the main flux from the rotor. So the output signal from Hall-ICs is used to drive a power transistor to control the stator winding current. Instead of using three Hall-ICs and encoder, this paper uses only two Hall-ICs for the permanent magnet rotor position and for the speed feedback signals, and uses a micro controller of 16-bit type(80C196KC) with the 3 phase PM BLDC whose six stator and two rotor designed. Two Hall-IC Hc and $H_B$ are placed on the endplate at 120 degree phase difference. With these elements, we estimate information of the other phase in sequence through a rotating rotor.

• Korean Journal of Weed Science
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• v.10 no.4
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• pp.255-260
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• 1990

Seventeen different herbicides were screened to select promising ones for the control of weeds, which may be used in paddy fields transplanted with 8 days old young rice seedlings. Four classes of herbicides were chosen and tested with seedlings grown under different cultivating conditions. Contact herbicides such as diphenyl-ether and oxadiazol showed severe growth retardation of rice seedlings. Carbamate class(dimepiperate), quinoline class (quinclorac), pyrazol class(pyrazolate), acid amide class(mefenacet and pretilachlor), addition of safener (pretilachlor+fenclorim and mefenacet+bensulfuron+dymuron) and unknown class (KC-7079) exhibited normal growth of seedlings. Sulfonyl urea herbicide class(cimosulfuron, bensulfuron, pyrazosulfuron), and oxarane class(tridiphane) showed the slight growth inhibition but recovered shortly.