• 간호행정학회지
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• 제18권4호
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• pp.402-413
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• 2012

Purpose: This study was done to explore factors related to amount of service use for elders with long-term care needs. Methods: A descriptive-correlation design was used. The sample included 259 elders and their primary caregivers who had cared for the elders for at least 6 months. Data on long-term care need assessment, service use and interviews with primary caregivers were analyzed. Results: There was no significant relationship between the sociodemographic characteristics and the amount of services use. Amount of service use differed significantly by Long-term care classification. The mean scores for class 1, 2 and 3 were 22.68, 21.47 and 17.87 days respectively. Primary caregiver relationship with the elders and the number of family-friend helpers were also significant. Multivariate regression analysis showed that gender, marital status, activities of daily living, cognitive impairment, and secondary caregiver support explained 17% of the total variance of service use among these elders (F=3.50, p<.001). Conclusion: The results of this study indicate that critical factors including secondary caregiver support and individual background, and other functional dependencies except for physical function should be considered in accurately predicting the amount of service use for community dwelling elders with long-term care needs.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.3810-3836
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• 2014

Geo-location white space spectrum databases (GL-WSDBs) are currently the preferred technique for enabling spectrum sharing between primary users and secondary users or white space devices (WSDs) in the very-high frequency (VHF) and ultra-high frequency (UHF) bands. This is true because technologies for making low-cost WSDs capable of autonomous sensing and detection of available white space (WS) spectrum are not yet feasible. This paper reviews the necessary enabling technical conditions to allow coexistence of primary and secondary systems in the VHF and UHF spectrum through a GL-WSDB approach. The practical implementation of South Africa's first GL-WSDB was performed. Results of WS channels available from five cities in South Africa calculated from the implemented GL-WSDB was compared with a commercially available GL-WSDB and was found to be 68% similar. Additionally, results from the implemented GL-WSDB were compared with measurements obtained from field spectrum scanning campaigns at two different locations in Cape Town, South Africa, and was found to be 64% similar.

• Nuclear Engineering and Technology
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• 제50권3호
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• pp.356-367
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• 2018

A series of tests dedicated to station blackout (SBO) accident scenarios have been recently performed at the $Prim{\ddot{a}}rkreislauf-Versuchsanlage$ (primary coolant loop test facility; PKL) facility in the framework of the OECD/NEA PKL-3 project. These investigations address current safety issues related to beyond design basis accident transients with significant core heat up. This work presents a detailed analysis using the best estimate thermal-hydraulic code TRACE (v5.0 Patch4) of different SBO scenarios conducted at the PKL facility; failures of high- and low-pressure safety injection systems together with steam generator (SG) feedwater supply are considered, thus calling for adequate accident management actions and timely implementation of alternative emergency cooling procedures to prevent core meltdown. The presented analysis evaluates the capability of the applied TRACE model of the PKL facility to correctly capture the sequences of events in the different SBO scenarios, namely the SBO tests H2.1, H2.2 run 1 and H2.2 run 2, including symmetric or asymmetric secondary side depressurization, primary side depressurization, accumulator (ACC) injection in the cold legs and secondary side feeding with mobile pump and/or primary side emergency core coolant injection from the fuel pool cooling pump. This study is focused specifically on the prediction of the core exit temperature, which drives the execution of the most relevant accident management actions. This work presents, in particular, the key improvements made to the TRACE model that helped to improve the code predictions, including the modeling of dynamical heat losses, the nodalization of SGs' heat exchanger tubes and the ACCs. Another relevant aspect of this work is to evaluate how well the model simulations of the three different scenarios qualitatively and quantitatively capture the trends and results exhibited by the actual experiments. For instance, how the number of SGs considered for secondary side depressurization affects the heat transfer from primary side; how the discharge capacity of the pressurizer relief valve affects the dynamics of the transient; how ACC initial pressure and nitrogen release affect the grace time between ACC injection and subsequent core heat up; and how well the alternative feeding modes of the secondary and/or primary side with mobile injection pumps affect core quenching and ensure stable long-term core cooling under controlled boiling conditions.

• 컴퓨터교육학회논문지
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• 제10권1호
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• pp.9-19
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• 2007

최근 초 중등학생들을 위한 정보통신윤리교육의 중요성이 많이 부각되고 있어서 이를 위한 연구 및 새로운 교재의 개발 등 활발한 활동들이 진행되고 있다. 한편, e-러닝이 활성화되면서 학습자 특성과 요구사항을 고려한 교육을 여러 방면으로 시도하고 있는데, 정보통신윤리교육도 예외는 아니다. 만일, 학습자 특성이나 요구사항을 정확하게 파악하여 교육을 한다면 한층 교육적 효과를 높일 수 있을 것이다. 본 논문에서는 정보통신윤리교육을 위한 수업 설계 시 학습자 특성과 요구를 반영하고자 고려해야 할 수업 설계 요소들을 수업목표, 수업유형, 수업내용, 수업매체로 나누어 설문을 한 후, 이를 바탕으로 컨조인트 분석을 실시한다. 즉, 수업 설계 요소에 대한 상대적 중요도를 분석하여 수업 설계 요소간의 차이를 기술하고 정보통신윤리교육을 위한 바람직한 수업 설계 방안을 제안한다.

• 전력전자학회논문지
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• 제17권5호
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• pp.445-452
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• 2012

The impurity detection method applied to existing discriminated the normality(R, L, C) and impurity(Metal) load using mutual RFID/ID method in the contactless power supply in which the primary side and the secondary side are completely separation by using the contactless transformer. However, this kind of system is caused the high cost of the system and complexity of control. Therefore, in this paper was proposed the contact-less power transfer using the primary current that determine normality or impurity load by compare the primary current Amplitude to reference quantity value and design the 3[W] contact-less power transfer and conduct an experiment for demonstrate the validity.

• Journal of Positioning, Navigation, and Timing
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• 제10권4호
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• pp.307-313
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• 2021

Modernized GNSS signal structures tend to use tiered codes, and all GNSSs use binary codes as secondary codes. However, recently, signals using polyphase codes such as Zadoff-Chu sequence have been proposed, and are expected to be utilized in GNSS. For example, there is Tiered Differential Polyphase Code (TDPC) using polyphase code as secondary code. In TDPC, the phase of secondary code changes every one period of the primary code and a time-variant error is added to the carrier tracking error, so carrier tracking ambiguity exists until the secondary code phase is found. Since the carrier tracking ambiguity cannot be solved using the general GNSS receiver architecture, a new receiver architecture is required. Therefore, in this paper, we describe the carrier tracking ambiguity and its cause in signal tracking, and propose a receiver structure that can solve it. In order to prove the proposed receiver structure, we provide three signal tracking results. The first is the differential decoding result (secondary code sync) using the general GNSS receiver structure and the proposed receiver structure. The second is the IQ diagram before and after multiplying the secondary code demodulation when carrier tracking ambiguity is solved using the proposed receiver structure. The third is the carrier tracking result of the legacy GPS (L1 C/A) signal and the signal using TDPC.

• 한국철도학회논문집
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• 제13권4호
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• pp.404-411
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• 2010

철도차량용 선형유도전동기(Linear Induction Motor, LIM) 축소-회전형 모델의 기본 설계 결과를 검증하기 위하여 LIM의 자기등가회로법을 이용한 파라미터 도출 및 특성 계산을 수행하였다. LIM의 경우, 자기등가회로상의 파라미터는 LIM의 전기자 코어와 2차측 알루미늄 도체판의 형상 및 공극에 대한 함수로써 표현이 가능하다. 즉 전기자 코어와 2차측 알루미늄 도체판의 형상 및 공극 변경에 의해 LIM의 특성이 크게 달라질 수 있다는 것을 의미한다. 따라서 본 연구에서는 철도차량용 LIM 축소-회전형 모델의 공극, 2차측 AL-Plate의 두께, 오버행 길이, 형상 변경에 따른 LIM 축소-회전형 모델의 자기등가회로 파라미터 및 특성의 변화 추세를 분석하여, 철도차량용 실모델 LIM 개발을 위한 기초 연구를 수행하였다.

• 공업화학
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• 제20권2호
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• pp.234-240
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• 2009

마그네슘염과 알칼리를 출발물질로 하는 수산화마그네슘 제조에서 공정 변수가 생성되는 입자의 크기, 형상 및 응집도에 미치는 영향에 대해 완전 요인배치(full factorial) 실험계획법(Design of experiment)으로 연구하였다. 수열합성에서는 알칼리/$MgCl_2$ 몰 비가 낮을수록, $MgCl_2$ 농도와 수열처리 온도가 높을수록 평균입경은 커지고 1차 입자 크기와 2차 입자 크기가 유사하지만, 침전법으로 제조한 수산화마그네슘은 1차 입자의 응집현상으로 2차 입경은 커지며, 응집성은 알칼리원의 종류와 $MgCl_2$의 농도에 따라 달라졌다. 알칼리원의 종류에 따른 차이는 $NH_4OH$를 사용한 경우 NaOH를 사용한 것보다 입자의 크기가 커지고 분산성이 우수하였다. 크기 및 표면 상태가 다른 샘플을 선정하여 LDPE와 EVA 혼합수지에 혼합하여 난연 특성을 비교하였을 때, 50, 55% 함량에서는 일반적으로 2차 입경 크기가 감소함에 따라 LOI값은 상승하지만, UL-94에서는 1차 입자가 작은 경우에 더 우수한 등급을 받는 경우가 있었다. 60%의 높은 함량에서 입자의 제조경로와 무관하게 UL-94는 V0 등급이지만, 미립이더라도 응집성있는 경우 한계산소지수가 상대적으로 낮다는 것을 알 수 있었다.

• Journal of Power Electronics
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• 제19권5호
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• pp.1122-1132
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• 2019

In this paper, aiming at high-voltage applications, transformer windings schemes of multiple-output two-transistor flyback converters are investigated, which are mainly based on the stray capacitances effect. First, based on a transformer model including equivalent stray capacitors, the operational principle of the converter is presented, and the main influence of its stay capacitors is determined. Second, the windings structures of the transformer are analyzed and designed based on the stray capacitances effect. Third, the windings arrangements of the transformer are analyzed and designed through a coupling analysis of the secondary windings and a stray capacitance analysis between the primary and secondary windings. Finally, the analysis and design conclusions are verified by experimental results obtained from a 60W laboratory prototype of a multiple-output two-transistor flyback converter.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.5015-5027
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• 2015

Transceiver optimization in multiple input multiple output (MIMO) cognitive systems is studied in this paper. The joint transceiver beamformer design is introduced to minimize the transmit power at secondary base station (SBS) while simultaneously controlling the interference to primary users (PUs) and satisfying the secondary users (SUs) signal-to-interference-plus-noise ratio (SINR) based on the convex optimization method. Due to the limited cooperation between SBS and PUs, the channel state information (CSI) usually cannot be obtained perfectly at the SBS in cognitive system. In this study, both perfect and imperfect CSI scenarios are considered in the beamformer design, and the proposed method is robust to CSI error. Numerical results validate the effectiveness of the proposed algorithm.