• ETRI Journal
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• v.45 no.6
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• pp.963-973
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• 2023

Non-orthogonal multiple access (NOMA) is considered a key candidate technology for next-generation wireless communication systems due to its high spectral efficiency and massive connectivity. Incorporating the concepts of multiple-input-multiple-output (MIMO) into NOMA can further improve the system efficiency, but the hardware complexity increases. This study develops an energy-efficient (EE) subchannel assignment framework for MIMO-NOMA systems under the quality-of-service and interference constraints. This framework handles an energy-efficient co-training-based semi-supervised learning (EE-CSL) algorithm, which utilizes a small portion of existing labeled data generated by numerical iterative algorithms for training. To improve the learning performance of the proposed EE-CSL, initial assignment is performed by a many-to-one matching (MOM) algorithm. The MOM algorithm helps achieve a low complex solution. Simulation results illustrate that a lower computational complexity of the EE-CSL algorithm helps significantly minimize the energy consumption in a network. Furthermore, the sum rate of NOMA outperforms conventional orthogonal multiple access.

• Women's Health Nursing
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• v.30 no.2
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• pp.140-152
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• 2024

Purpose: Social support is essential for postpartum well-being, but little is known about the postpnatal social support preferred by primiparous women. This study aimed to comprehensively understand and describe the meaning of postnatal social support experience in primiparous women. Methods: The participants were seven primiparous women who were within 1 year after childbirth, recruited through purposive and snowball sampling from an online parenting community. The data were collected through in-depth interviews from November 14 to 28, 2022. Participants were interviewed face-to-face or via phone or online platform, according to their choice. Colaizzi's phenomenological qualitative research method was applied to analyze the meaning of the participants' experience. Results: Five theme clusters and fourteen themes were identified from the data. The five theme clusters are as follows: (1) Shortcomings of the childbirth and postpartum care system I learned through my experience; (2) Government policies focusing on childbirth and child-rearing rather than postpartum recovery; (3) Driving force of postpartum recovery: Shared childbirth process; (4) Childcare on my own; and (5) Conflicted between being a stay-at-home mom and a working mom under inadequate maternity protection policies. Conclusion: Despite postpartum support from the government that was perceived as inadequate, first-time mothers regained confidence and motivation for parenting with the help of family, peers, and social networks. First-time mothers need support from professionals and reliable online communities for postpartum recovery and parenting.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.1
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• pp.69-78
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• 2005

ARCO and TAO data which supply three dimensional global ocean information are assimilated to the background field from a general circulation model, MOM3. Using a variational Analysis using Filter (VAF), which is a spatial variational filter designed to reduce computational time and space efficiently and economically, observed ARGO and TAO data are assimilated to the OGCM-generated background sea temperature for the generation of initial condition of the model. For the assessment of the assimilation impact, a comparative experiment has been done by integrating the model from different intial conditions: one from ARGO-, TAO-data assimilated initial condition and the other from background state without assimilation. The assimilated analysis field not only depicts major oceanic features more realistically but also reduces several systematic model bias that appear in every current OGCMs experiments. From the 10-month of model integrations with and without assimilated initial conditions, it is found that the major assimilated characteristics in sea temperature appeared in the initial field remain persistently throughout the integration. Such implies that the assimilated characteristics of the reduced sea temperature bias is to last in the integration without rapid restoration to the non-assimilated OGCM integration state by dispersing mass field in the form of internal gravity waves. From our analysis, it is concluded that the data assimilation method adapted in this study to MOM3 is reasonable and applicable with dynamical consistency. The success in generating initial condition with ARGO and TAO data assimilation has significant implication upon the prediction of the long-term climate and weather using ocean-atmosphere coupled model.

• KDI Journal of Economic Policy
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• v.36 no.3
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• pp.121-168
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• 2014

After analyzing and finding the explaining factors about the "Effect of My Mom's Friend's Son (MMFS Effect)" with online-surveyed data, we introduce this concept into the conventional job search theory to develop it further. We try to estimate its effects on the hazard rate of youth pre-employment duration with some proxy variables such as his/her parents' schooling, living with parents dummy, increasing rate of consumer price index representing the burdens of parents, monthly temporary/daily workers ratio, relative ratio of quarterly 90th percentile urban household income, monthly average wage differentials between the workers of large and small firms, etc. The results confirm us the fact that so called "MMFS Effect" has been effective enough and strengthened up to recently. The conventional job search theory should be extended to be able to introduce the influencing effects of other person's success, for instance MMFS's success, on the job search behavior of youths, too.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.118-118
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• 2012

수자원의 효율적 이용 및 관리는 심화되고 있는 기후변화에 선제적으로 대응하고 발생가능한 물위기에 대비하기 위한 필수조건이다. 그 중 가장 핵심이 되는 요소는 댐에 저수된 물을 효과적으로 이용하는 것, 즉 댐 건설목적에 따라 시간 및 공간별로 적절하게 할당시키는 것이라고 할 수 있다(Kim, 1998). 그러나 단일 댐의 운영과는 달리 수계내 댐군의 연계 운영은 매우 복잡하고 어려운 문제이다. 연계된 댐들간 저수 상황을 고려하여 유역내 시 공간적인 용수 수요의 지속적인 충족을 위하여 유입량 예측의 정확성을 높이도록 하고, 상류 댐에 최대한 저류하도록 하며, 여수로 방류 같은 불필요한 방류를 최소화 하고, 서로 상충되는 목표를 갖고 있지만, 홍수용량 및 발전수위를 최대로 확보하도록 하여야 한다. 이처럼 댐 운영을 위한 실제 상황은 단일 목적에 의한 최적화와는 달리 여러 상충되는 목적 및 구성 요소들간의 타협, 조정을 필요로 한다. 댐군의 연계운영 문제는 1960년대 초부터 현재까지 활발히 연구가 진행되어 온 분야 중 하나이나 문제의 복잡성과 어려움으로 인해 아직까지도 최선의 방안을 제시하기 어려운 문제이다(ReVelle, 2000). 이를 위한 방법은 시뮬레이션 모형 활용기법과 최적화 모형 활용기법으로 대별할 수 있으며 각 방법의 서로 다른 구조적 특성과 장단점으로 인하여 이원화된 체계로 사용되는 것이 현재의 국내 실정이다. 대부분의 실무에서는 이해도도 쉽고, 비교적 결과를 빨리 도출할 수 있는 시뮬레이션 기반의 모형을 활용하며 대표적으로 HEC-5, K-ModSim, HEC-ResSim 등이 활용되어왔다. 반면, 학계에서는 DP, MIP, SLP, SDP 등 최적화기법을 댐운영에 활용 할 것을 제안하고 있지만, 활용에 대한 거부감이 남아있는 것이 현실이다. 본 연구에서는 시뮬레이션과 최적화기법의 원론적 비교를 통해 각 방법의 장단점과 한계점을 분석하고, 왜 이원화된 사용체계로 되었는지에 대한 고찰과 이에 대한 해결책으로 시뮬레이션모형의 장점과 최적화기법의 장점을 결합한 모형을 제안한다. 국내에는 Kim and Park(1998)이 시뮬레이션 기반의 최적화 모형 CoMOM(Coordinated Multi-Reservoir Operating Model)을 개발하였으며, 이후 21C프론티어 연구사업(2001-2011)에서 모형의 보완수정 검증을 통해 실무 활용도를 높여 왔다. 본 연구를 통하여 거부감의 원천을 추적해 보고, 타당한 이유가 있는지 대한 것을 심층 분석해보고, CoMOM모형과 시뮬레이션 모형, 다른 최적화 기법들과의 원론적 비교를 통해 각 방법들의 효율적인 활용방안과 최적화모형의 구체적인 활용방안을 제시하고자 한다.

• The Korean Journal of Coaching Psychology
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• v.4 no.2
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• pp.1-26
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• 2020

The purpose of this study was to develop and validate the Psychological Difficulties Scale of Working Moms(PDSWM). In the first study, 69items and 17 factors of the inventory were obtained based on interview, open-ended questionnaires. In the second study, the on-line surveys from 306 working mom was carried to analyze factor structure of the PDSWM. The final result showed that the 12 factor model with 64 items was appropriate. The third study was collected from 638 working mom and in order to make certain the cross-validity of the inventory, the group was divided into two groups (each group with 319 employees). The results of exploratory factor analyses using data of group 1 showed that the 8 factor structure with 48 items was appropriate. Also the results of confirmatory factor analysis using data of group 2 showed that the 8 factor structure indicated a satisfactory fit. Final 8 factors were as follows: 1) Feeling Apologetic to family members 2) Discrimination at workplace 3) burnt-out: both body and mind 4) Unequal distribution of child-rearing and house chore labor 5) Conflict with the babysitter/grandparents 6) Limit in further strengthening work competency 7) Social prejudice 8) Difficulty being on time for work. The PDSWM was significantly correlated with various criteria such as organizational commitment, life satisfaction, and work engagement. Based on such findings, implications, limitations, and the suggestions for future study were discussed.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1998.10a
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• pp.861-866
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• 1998

본 논문은 프로우브 급전한 주기적인 위상 배열 마이크로스트립 안테나의 계산된 결과를 제시한다. 수치적인 마들은 엄밀한 그린 함수와 캘러킨 (Galerkin)해에 근거를 둔다. 임의의면(plane)에서의 입력 임피던스를 스캔 각도에 따라 계산하여 반사계수를 구하고 유전체의 유전율과 두께가 위상 배열 안테나에 미치는 영향을 제시한다. 표면파에 의한 스캔 블라인드 현상을 설명하고 유전체의 두께에 따른 E-면과 H-면에서의 입력 임피던스 대역폭을 계산한다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.193-195
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• 2002

본 논문에서는 최근에 제안된 Hybrid 방식의 모바일 멀티캐스트 프로토콜 중 MOM, MMA, RBMOM, 그리고 TBMOM 프로토콜에 대해서 여러 가지 관점에서 성능을 비교하여 각 프로토콜의 장단점을 분석함과 동시에, 이들 방식이 공통적으로 가지는 DMSP(Designated Multicast Service Provider) 핸드오프 문제에 대해서 Smooth DMSP 핸드오프방식을 제안한다.

• Journal of Biomedical Engineering Research
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• v.13 no.1
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• pp.9-18
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• 1992

This paper describes a quantitative analysis of electromyography (EMG) measured from seven subjects performing four seated dynamic tasks. EMG signals were mom- bored using 15 surface electrodes which were placed on selected trunk and lower extrmity muscles of the right side of the body. Each EMG signal was then processed through rectification, integration, and filtering. Based on the maximum level of the processed EMG, it was found that the trunk and ankle muscles play an important role on the postural control during the seated tasks.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.136-137
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• 2007

The emission of external incident field or near device field is important factor of EMI and EMC. In this paper, we apply MOM, using the RWG basis function, to analysis the induced current distribution on the PEC and dielectric plates. The volume and surface integral equations are presented for the electromagnetic wave scattering from plate structures composed of dielectric and conducting objects.