• Journal of Magnetics
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• 제18권2호
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• pp.202-206
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• 2013

In this paper, the MFL (magnetic flux leakage) signals of complex defects on the underground gas pipeline are analyzed and their depths are estimated. Since closely-located defects (complex defects) affect each other, accelerate the progress of defection, and are finally combined to one (cluster), it's meaningful to differentiate complex defects from single defects by analyzing their characteristics. Various types of complex defects are characterized and analyzed by defining the safety distance for interference. 26 artificial defects are carved on the pipeline simulation facility (PSF) to analyze the characteristics of complex defect and demonstrate the accuracy of the proposed complex defect estimation. The proposed method shows average length error of 5.8 mm, average width error of 15.55 mm, and average depth error of 8.59%, respectively.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.277-278
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• 2012

본 논문은 고조파(Harmonics) 규제 만족을 위해 사용되는 리액터와 EMI(Electro-Magnetic Interference) 필터 회로에 관한 것으로서, 기존의 고조파 규제와 150kHz ~ 30MHz 대역의 EMI CE(Conducted Emission) 규제를 만족하기 위하여 각각 사용했던 리액터와 EMI 필터의 CM Choke 코일을 CM Choke의 누설 인덕턴스를 이용하여 CM Choke 코일 하나로 대체한다. 결과적으로 기존의 리액터 소자를 제거함으로써 사용 소자 개수 저감에 따른 부피 및 가격 저감을 실현할 수 있다는 장점을 가진다. 또한 실제 제품에 적용해 고조파, EMI 측정결과 문제가 없음을 검증하였으며, 온도 특성도 문제가 없음을 확인했다.

• 한국통신학회논문지
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• 제32권12C호
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• pp.1175-1187
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• 2007

이동통신 기지국 시스템에서 송신 신호의 PAR 성능을 (peak-to-average power ratio) 개선함으로써 범용 전력 증폭기의 사용이 가능하게 되며, 이로 인해 전체적인 기지국 비용의 절감을 기대할 수 있다. 일반적으로 PAR 값을 줄임으로 인해 기지국 송신신호의 인근 대역 간섭 제한 성능을 나타내는 ACLR이나 (adjacent channel leakage ratio) 품질을 나타내는 EVM이나 (error vector magnitude) PCDE 성능의 (peak code domain error) 열화를 발생시킨다. 본 논문에서 이러한 문제점을 해결하기 위하여 필터링 기반의 CFR 방식인 (crest factor reduction) FDCFR 알고리즘을 (filter-dependent CFR) 소개하며, 히스토그램 기반 코드 영역 보상(HBWCDC; histogram based waterfilling code domain compensation)기법을 제안한다. 본 논문에서 제안한 CFR 알고리즘은 PAR 감소뿐만 아니라 앞서 언급한 ACLR, EVM 및 PCDE등의 성능 열화를 방지한다.

• 성인간호학회지
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• 제16권3호
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• pp.398-408
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• 2004

Purpose: The purpose of this study was to identify the frequency of urinary incontinence and lower urinary symptoms, to identify lifestyle and sexual matters for UI of adult women in an urban area. Method: The sample consisted of 364 educated women from a women's health education program in a public health center. For data collection, the Bristol Female Lower Urinary Tract Symptoms Questionnaire developed by Jackson, et. al.(1996) and the demographic questionnaire were used. For data analysis, SAS 8.2 program was used. Result: The results were as follows: 1. the prevalence rate of UI was 73.63%. 45.88% of them were stress incontinence and 27.75% of them were urge incontinence. 2. Remarkable differences were found between the type of UI and LUTS in the case of urgency($x^2=42.0585$, P<0.001), unexplained incontinence($x^2=59.0585$, P<0.001), noctural incontinence($x^2=18.8080$, P<0.001) and catetherization($x^2=10.7207$, P= 0.004), burning sense($x^2=27.7400$, P<0.001). 3. Remarkable differences were found between the type of UI and lifestyle matters in the cases as follows fluid intake restriction($x^2=31.0532$, P=0.008), interference in physical activity($x^2=36.7481$, P=0.001), interference in relation with others($x^2=22.2729$, P=0.034). 4. Remarkable differences were found between the type of UI and sexual matters with difficulty of sexual intercourse($x^2=16.1898$, P=0.002), and urine leakage during sexual intercourse($x^2=17.9752$, P=0.001). Conclusion: Based on the results, developing and carrying out an adequate UI care and education program is needed.

• 대한간호학회지
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• 제28권1호
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• pp.171-183
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• 1998

The purpose of this study was to identify the incidence of urinary incontinence in adult women and to identify factors related to life style and sexual intercourse that were related to incontinence. The sample consisted of 1,065 women living in Seoul or one of five provinces. Data for this study were collected from January 16 to June 23 using structured questionnaires. The Urinary Symptom Questionnaire developed by Jackson and a demographic questionnaire were used to collect the data. The data were analyzed using frequency, percentage with an SPSS/PC$^{+}$ program. The major finding are as follows : 1. The distribution of age of subjects was as follows : 20-29(10.1%), 20-39(17.8%), 40-49(27.3%). 50-59(22.3%), 60-69(12.9%), 70-79(6.1%). 80-89(2.8%), more than 90(0.6%). The frequency of normal delivery, 0(155%), 1-2(36.0%), 3-4(29.2%), 5-6(13.0%). more than 7(6.3%). The rate of subjects with menopause was 40.8%. 2. It was reported that 50.7% of the subjects experienced urinary incontinence with stress, mixed. and urgency incontinence being 49.8%, 43.4%, 6.8% respectively. 3. The lower urinary symptoms and incidence with urinary incontinence were as follows : Daily frequency. 22.3%, nocturia. 40.8%, urgency, 71.2%, bladder pain 47.8%, unexplainned incontinence, 32.4%, noctural incontinence, 16.1%, and frequency of incontinence, 37.7%. In term of quantity of incontinence, drop/pants damp, 29.5%, dribble/pants wet, 20.5%, flood or soaking through to outer clothing, 1.7%, and flood or running down legs or onto floor, 0.2%. 4. The symptoms related to sexual intercourse and incidence of urinary incontinence were as follows : dry vagina, 39.1%, sex life trouble, 10.8%, pain during sexual intercourse, 27.4%, and urine leakage during sexual intercourse. 8.8%. 5. Life style problems related to urinary incontinence were as follows : fluid intake restriction, 20.0%, affected daily task, 24.5%. avoidance of placess and situations, 35.0%, interference in physical activities, 30.6%, interference in relationships with other people. 19.0%. interference in relationships with husband/companion, 8.1%, and time after attack of urinary symptoms, 76.9%. In term of the feeling about the rest of their lifves the women reported : perfectly happy, 11.3%. pleased, 16.9%. mostly satisfied, 20.2%, mixed feelings, 21.0%, mostly dissatisfied, 21.0%, very unhappy 8.5%, and desperate. 1.0%. In conclusion. this study was a preliminary study to provide nursing practices guidelines for incontinence in adult women. Nurse working with adult women should develop and provide adequate care for these women.n.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권10호
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• pp.4759-4780
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• 2017

Full Dimension multiple input multiple output (FD-MIMO) architecture employs a planar array design at the Base Station (BS) to provide high order multi-user MIMO (MU-MIMO) via simultaneous data transmission to large number of users. With FD-MIMO, the BS can also adjust the beam direction in both elevation and azimuth direction to concentrate the energy on the user of interests while minimizing the interference leakage to co-scheduled users in the same cell or users in the neighboring cells. In a typical highly populated macrocell environment, modelling the elevation angular characteristics of three-dimensional (3D) channel is critical to understanding the performance limits of the FD-MIMO system. In this paper, we study the throughput performance of FD-MIMO system with varying elevation angular spread and inter-element spacing using a 3D spatial channel model. Our results show that for a typical urban scenario, horizontal beamforming with correlated antenna spacing achieves optimal performance but by restricting the spread of elevation angles of departure, elevation beamforming achieves high array gain with wide inter-element spacing. We also realize significant gains due to spatial array processing via modelling the elevation domain and varying the inter-element spacing for both the transmitter and receiver.

• 대한조선학회논문집
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• 제46권5호
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• pp.545-551
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• 2009

In naval architecture and offshore engineering, the development and a broad use has been achieved in the field of flow control valves for pipe system. Butterfly valves are also widely used for flow control, but there are not many studies for triple-eccentric butterfly valves. Moreover, if the fluid of pipeline flows in the bi-direction then it makes more complicate to adapt triple-eccentric butterfly valves to flow control. In this study, we are trying to develop a bi-directional triple-eccentric butterfly valve through sealing mechanism and stem design study. Digital mockup using 3D CAD was constructed for shape interference check and structural analysis was conducted for structural safety. Also we performed leakage test to check out the durability of the bi-directional pressure for the developed valve.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.220-222
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• 2007

With the wide spread of direct current (DC) electric railroads in Korea, the stray currents or leakage currents from negative return rails become a pending problem to the safety of nearby underground infrastructures. The most widely used mitigation method for this interference is the stray current drainage method, which connects the underground metallic structures to the rails with diodes (polarized drainage) or thyristor (forced drainage). Although this method inherently possesses some drawbacks, its cost effectiveness and efficiency to protect the interfered structures has been the main reason for the wide adoption. In this paper, we show the field test results for the application of stray current drainage system to a city gas pipeline paralleling a depot area of a metropolitan rapid transit system. The process for optimal positioning is briefly illustrated. The effectiveness of constant voltage, constant current, and constant potential drainage schemes was also described.

• 디지털산업정보학회논문지
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• 제11권1호
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• pp.69-78
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• 2015

Internet of Things(IoT) is electronic devices and household appliances use wireless sensor network in environment of high speed wireless network and LTE mobile service. The combination of the development of Internet and wireless network led to development of new forms of service such as electronic devices and household appliances can connect to the Internet through various sensors and online servers such as a Home Network. Even though Internet of Things is useful, there are problems in Internet of Things. In environment of Internet of Things, information leakage could happens by illegal eavesdropping and spoofing. Also illegal devices of wireless communication interference can cause interfere in Internet of things service, physical damage and denial of service by modulation of data and sensor. In this thesis, it will analyze security threats and security vulnerability in environment of mobile services and smart household appliances, then it will suggest plan. To solve security issues, it is important that IT and RFID sensor related companies realize importance of security environment rather than focus on making profit. It is important to develop the standardized security model that applies to the Internet of Things by security-related packages, standard certification system and strong encrypted authentication.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권4호
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• pp.343-349
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• 2005

This paper proposes a novel zero-voltage-switching (ZVS) Push-pull DC-DC Converter for high input voltage and high power applications. This topology utilizes two switches in series to replace one switch in conventional push-pull converter, and two clamping diodes are introduced. The voltage stress of the switches is the input voltage, and the switches can realize ZVS with the use of the leakage inductance of the transformer. Furthermore, secondary full-wave rectifier with a clamping capacitor is used to eliminate the voltage oscillation and spike of the rectifier diodes due to the reverse recovery. Therefore, the electromagnetic interference is reduced effectively. The operation principle of the proposed converter is analyzed theoretically. The output characteristic, ZVS condition and design principle of the clamping capacitor are discussed. Experimental results obtained from a 270V input 2kW prototype with $95.8\%$ high efficiency confirms the design.