• Korean Chemical Engineering Research
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• 제60권1호
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• pp.12-19
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• 2022

소형 이송형 고분자전해질 연료전지 (PEMFC)에 많이 사용되는 cathode 개방형 PEMFC 스택은 내구성이 약한 문제점이 있다. 13개의 셀로 이루어진 PEMFC 스택의 가속 내구성 평가를 통해 스택의 열화 원인을 찾고 cathode 개방형 스택의 내구성 향상에 기여하고자 하였다. Cathode가 대기에 개방되어 있고, 기밀 유지가 어려운 cathode 개방형 스택의 구조적 문제점 때문에 시동/정지 (SU/SD)시 수소/공기 경계가 형성되어 cathode를 열화시킨다. 본 연구에서는 cathode 개방형 스택에 SU/SD 1,800회 반복 후 초기 성능의 54%가 감소하여 비교적 짧은 시간에 내구성을 평가할 수 있었다. 스택 해체 후 각 셀을 2등분하여 성능분석하였다. 전체적으로 공기 유입이 용이한 anode 출구부 MEA가 유입부 MEA보다 전극 열화가 더 심해서 SU/SD시 수소/공기 경계 형성이 주요 열화 원인임을 확인했다.

• 산업경영시스템학회지
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• 제45권3호
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• pp.197-203
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• 2022

Urban space expansion is an important symbol of the urbanization process and has always been an important topic in urban studies. In addition, for sustainable city management, it is important to identify factors that can influence, such as the driving force and direction of urban space expansion, from the stage of establishing an urban development plan. To understand these factors, by observing the expansion process of a specific city, it is possible to sufficiently observe how the urban spatial dimension changes. Through a series of processes, the spatial growth characteristics of the city are analyzed, and the influence and results of important factors are analyzed. For this purpose, this paper examines the changes in the city's outer boundary and land use structure through monitoring data on urban areas of 14 cities in Hunan Province, China from 2000 to 2016. Temporal and spatial regularity according to the urban space expansion of these cities were analyzed, and a preliminary assessment was made on whether the urban space expansion is coordinated with the urban population growth. The assessment result showed: (1) The urban space of most cities has been extended rapidly in 2000-2015 however, the rate and the intensity of urban space expanding has been declining. (2) The construction of the industrial park is the core driving force of the urban space expanding, and the change of the urban space structure is manifested as enclave city expansion because that the industrial park is usually far away from the city center. (3) The population agglomeration is another driving force of the urban space expanding. At this time, the urban space expanding is like boundary extension. (4) Except Changsha city, all of the cities has a high urbanization-area-growth elastic coefficient. It means that most of the cities should enhance the land use degree.

• 대한치과교정학회지
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• 제53권5호
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• pp.307-316
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• 2023

Objective: To evaluate the effects of an electric toothbrush with vibrational frequencies of 125 Hz and 150 Hz on the orthodontic tooth movement (OTM) rate and the production of prostaglandin E2 (PGE2). Methods: Out of thirty patients (aged 18-25 years; 16 females and 14 males), ten patients each formed Group A and B, who used electric toothbrushes with 125 Hz and 150 Hz vibrations, respectively. The remaining ten patients (Group C) served as the control group and did not use electric toothbrushes. The rate of OTM and levels of PGE2 using microcapillary pipettes were calculated before the start of retraction (T0), on the 30th day (T1), on the 60th day (T2), and on the 90th day (T3) from the start of retraction in all the groups. Results: There was a statistically significant difference in the mean OTM values and PGE2 levels in all three groups at different time intervals, with the maximum difference seen in Group B compared to Group A and least in Group C at T1, T2 and T3. Conclusions: The rate of OTM and levels of PGE2 were highest in patients who used an electric toothbrush with 150 Hz mechanical vibration compared to those who used an electric toothbrush with 125 Hz mechanical vibration and least in patients who did not use an electric toothbrush. Mechanical vibration led to an increase in the PGE2 levels and accelerated the OTM.

• 벤처혁신연구
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• 제3권2호
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• pp.177-195
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• 2020

세계가 점점 더 통합됨에 따라 자선단체는 국내 문제 뿐만 아니라 빈곤, 기근, 자연 재해 등 세계 전역에서 일어나는 문제들을 다루게 되었다. 국제적으로 많은 조직들이 도움을 제공하고 이러한 문제들을 완화시키기 위해 노력하고 있지만, Jusoor, Karam Foundation, Save the Children, 그리고 Oxfam 등 대부분의 자선단체들이 서구사회에 기초하고 있다. 이 논문은 동양과 서양 두 지역 사이에 기부 문화 불균형이 존재하는 이유를 분석한다. 이 논문은 지역적 차이를 설명하면서 자선 재단에 대한 아시아인들의 뿌리 깊은 불신과 아시아에서의 자선 기부를 장려하는 정부 정책의 부재, 그리고 추세를 형성하는 다른 여러 사회적, 경제적, 정치적 요인에 특히 초점을 맞추고 있다. 아시아가 세계의 다른 지역에 비해 자선 문화에서 왜, 그리고 얼마나 크게 뒤처지는지를 분석한 결과, 이 논문은 아시아 자선 시장에 "창조적 파괴"가 필요하다는 것을 증명한다. 더 나아가 이 논문은 혁신적인 신생 기업이 새로운 형태의 기술, 즉 등록 파트너쉽 기반을 갖춘 접근하기 쉬운 애플리케이션을 도입하여 정기적으로 앱 사용자들의 기부금 사용처와 금액을 업데이트함으로써 아시아 자선 사업의 신뢰도를 높일 수 있다고 제안한다. 이러한 새로운 형태의 기술은 아시아의 자선 문화를 둘러싼 다른 문제들을 다루는 데 또한 도움이 될 것이다.

• 한국컴퓨터정보학회논문지
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• 제28권12호
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• pp.49-56
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• 2023

본 연구에서는 트랜스포터의 할당 및 운행 순서를 최적화하기 위한 유전 알고리즘을 제안한다. 유전 알고리즘의 해는 리스트의 집합으로 표현되는데 각 리스트는 해당 트랜스포터가 작업할 순서를 나타낸다. 또한 성능 향상을 위해 효과적인 지역 탐색 연산을 결합한 혼합형 유전 알고리즘의 형태로 구현하였다. 지역 탐색 연산은 작업량이 적은 트랜스포터에서 작업의 블록을 꺼내어 다른 트랜스포터의 작업 목록에 삽입함으로써 트랜스포터 운용 대수의 감소를 유도한다. 제안하는 알고리즘의 효용성을 평가하기 위해 실제 조선소와 유사한 규모의 시뮬레이션 환경을 통해 Multi-Start 및 순수 유전알고리즘과 비교하였다. 가장 큰 규모의 문제에 대해 그들에 비해 트랜스 포터 수는 각각 40% 및 34%, 총작업 소요 시간은 27% 및 17% 감소시켰다.

• Clinics in Shoulder and Elbow
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• 제26권3호
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• pp.267-275
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• 2023

Background: Physical therapy (PT) plays an important role in the recovery of function following anatomic total shoulder arthroplasty (aTSA). While several PT protocols have been published for these patients, there is no standardized protocol for aTSA rehabilitation. This lack of standardization may lead to confusion between patients and physicians, possibly resulting in suboptimal outcomes. This study examines how PT protocols provided by academic orthopedic surgery programs vary regarding therapeutic goals and activities following aTSA. Methods: PT protocols for aTSA available online from the Accreditation Council for Graduate Medical Education accredited orthopedic surgery programs were included for review. Each protocol was analyzed to evaluate it for differences in recommendation of length of immobilization, range of motion (ROM) goals, start time for and progression of therapeutic exercises, and timing for return to functional activity. Results: Of 175 accredited programs, 25 (14.2%) had protocols publicly available, programs (92%) recommended sling immobilization outside of therapy for an average of 4.4±2.0 weeks. Most protocols gave recommendations on starting active forward flexion (24 protocols, range 1-7 weeks), external rotation (22 protocols, range 1-7 weeks), and internal rotation (18 protocols, range 4-7 weeks). Full passive ROM was recommended at 10.8±5.7 weeks, and active ROM was 13.3±3.9 weeks, on average. ROM goals were inconsistent among protocols, with significant variations in recommended ROM and resistance exercise start times. Only 13 protocols (52%) gave recommendations on resuming recreational activities (mean, 17.4±4.4 weeks). Conclusions: Publicly available PT protocols for aTSA rehabilitation are highly variable. Level of evidence: IV.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권7호
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• pp.1657-1670
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• 2013

The increase in the number of music files in smart phone and MP3 player makes it difficult to find the music files which people want. So, Query-by-Singing/Humming (QbSH) systems have been developed to retrieve music from a user's humming or singing without having to know detailed information about the title or singer of song. Most previous researches on QbSH have been conducted using musical instrument digital interface (MIDI) files as reference songs. However, the production of MIDI files is a time-consuming process. In addition, more and more music files are newly published with the development of music market. Consequently, the method of using the more common MPEG-1 audio layer 3 (MP3) files for reference songs is considered as an alternative. However, there is little previous research on QbSH with MP3 files because an MP3 file has a different waveform due to background music and multiple (polyphonic) melodies compared to the humming/singing query. To overcome these problems, we propose a new QbSH method using MP3 files on mobile device. This research is novel in four ways. First, this is the first research on QbSH using MP3 files as reference songs. Second, the start and end positions on the MP3 file to be matched are estimated by using multi-layered perceptron (MLP) prior to performing the matching with humming/singing query file. Third, for more accurate results, four MLPs are used, which produce the start and end positions for dynamic time warping (DTW) matching algorithm, and those for chroma-based DTW algorithm, respectively. Fourth, two matching scores by the DTW and chroma-based DTW algorithms are combined by using PRODUCT rule, through which a higher matching accuracy is obtained. Experimental results with AFA MP3 database show that the accuracy (Top 1 accuracy of 98%, with an MRR of 0.989) of the proposed method is much higher than that of other methods. We also showed the effectiveness of the proposed system on consumer mobile device.

• 호스피스학술지
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• 제5권1호
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• pp.42-49
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• 2005

To determine which are the culturally specific factors of Korean bereavement, this chapter focuses on the view of death and the traditional mourning process which reflect Korean values and norms. The formation of the Korean view and understanding of death has been strongly influenced by three of its major traditional religions: Shamanism, Buddhism, and Confucianism (Park:1994: Hao:1999) and Christianity more recently. Each religion has a different view of death and the appropriate expression of mourning. Korea accommodates funeral customs and rules strictly as a cultural system and has retained these traditions over a long period; hence, some of the traditional funeral rituals still remain in modern Korean life, although some of the rites have been simplified. We have looked at the various ways in which grief and mourning is displayed and shared in a collective manner over a long period of time. This fits in well within the other Eastern cultures that are collectively organized, and contrary to the Eurocentric models do not hastily seek to detach the living from the dead and recognize that grief is a long process, and different individuals may take different amounts of time to recover from the grief. The view of death and bereavement in Korea has sprung from the roots of three Korean religions, together with the recent addition of Christianity, although they mainly result from the three earlier religions. The beliefs of these religions are still closely linked together in the rituals of Korean bereavement on both conscious and unconscious levels. The influence of these religions is evident in practice through the bereaved family's mourning reactions, funeral rites and customs and its views about death. Korea used to have a period of mourning for three years, following traditional mourning rites; then the chief mourner and the bereaved families could return to their normal life. In spite of this long mourning process for the bereaved family, once the funeral ceremony is finished, people expect the bereaved family not to express their grief in public; even the bereaved family does not like to talk about death. The process for bereaved people is related to mourning processes in terms of detachment from the deceased in order to start a new life. Relatives and the community recommend the performance of the kut ceremony for relieving the grief of the bereaved. When one family member dies in an unlucky way, the bereaved family may have some fear or other psychological reactions of grief such as pain, depression, insomnia and nightmares, hallucinations or other physical reactions. Unlucky deaths give the bereaved a very painful time and these types of reactions are often more serious than reactions to natural death. But through the kut ceremony, the bereaved family can start to make a new relationship with the deceased. The taboo of this type of death and death generally remains a crucial aspect of the isolation that bereaved people might face and the collective nature of mourning(even where it is still present) is unable to address this aspect of the privatization of grief.

• 예술인문사회 융합 멀티미디어 논문지
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• 제7권3호
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• pp.329-337
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• 2017

본 논문에서는 서포트 벡터 머신의 중요한 파라미터인 C와 σ값을 빠르고 정확하게 찾는 탐색 방법론을 제안한다. 기존에 알려진 격자 탐색 방식은 모든 경우를 비교하기 때문에 탐색속도가 느리다. 이러한 문제점을 개선하기 위해 본 논문에서는 탐색속도 향상을 위한 딥 서치 방식을 제안한다. 1단계에서는 C-σ 정확도지표를 4등분 한 뒤 각 영역의 중간 값을 탐색하여 가장 정확도 값이 높은 지점을 시작 지점으로 선택한다. 2단계에서는 선정된 시작지점을 다시 4등분한 뒤 정확도 값이 가장 큰 지점을 새로운 탐색지점으로 지정한다. 3단계에서는 탐색지점에 이웃한 8개의 지점들을 탐색하여 정확도 값이 가장 높은 곳을 새로운 시작 지점으로 선정한 뒤 해당 지점을 4등분하여 정확도 값을 계산한다. 마지막 단계에서는 이웃 지점의 값들보다 탐색지점의 정확도지표 값이 최댓값이 될 때까지 진행한다. 최댓값을 만족하지 않을시 2단계에서부터 반복하며 입력된 레벨 값만큼 반복을 진행한다. 베어링의 결함 및 정상 데이터를 사용하여 비교한 결과, 제안한 Deep search 알고리즘은 기존 알고리즘 보다 성능 및 탐색시간에서 우수성을 보였다.

• 벤처창업연구
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• 제9권5호
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• pp.255-265
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• 2014

창업은 개인적 관점에서 보면 개인적인 부를 창출하기 위한 활동이고 사회적으로는 일자리 창출을 통한 경제활동 인구를 증가시키고 실업문제를 해결할 수 있는 중요한 활동이다. 창업은 성장과 고용간의 선순환 구조의 매개체 역할을 수행하고 경제의 안정 지속성장 토대를 제공하며 사회적 문제 해소에 기여할 수 있는 최선책일 수 있다. 따라서 본 연구에서는 대학생들의 직업성격유형에 따라서 직업의식과 창업의지에 영향을 미치는 요인은 무엇인지를 알아보고자 하였다. 금번 연구의 회귀 분석 결과 직업성격유형은 창업의지에 긍정적인 정(+)의 영향을 미치며, 각각 창업의지에 긍정적인 정(+)의 영향을 미침을 알 수 있었다. 또한 직업성격유형은 직업가치에 긍정적인 정(+)의 영향을 미치며, 직업가치는 창업의지에 긍정적인 정(+)의 영향을 미침을 알 수 있었다. 다만, 직업가치요인별로 창업의지에 미치는 관계를 살펴 본 결과 자아실현, 안전성, 권력, 독립성, 사회봉사, 지도성 항목이 보다 더 창업의지와 유의적인 관계가 확인하였다. 따라서 대학생 창업의 성공률을 향상시키기 위해서는 성격유형별로 적합한 창업아이템 선정과 선택적 창업 교육방안을 수립하고 적절한 시기에 창업을 접할 수 있는 기회를 제공해야만 한다.