• The Journal of Advanced Prosthodontics
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• 제11권4호
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• pp.202-208
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• 2019

PURPOSE. Fabrication of zirconia restorations with ideal mechanical properties in a short period is a great challenge for clinicians. The purpose of the study was to investigate the effect of heating rate on the mechanical and microstructural properties of monolithic zirconia. MATERIALS AND METHODS. Forty monolithic zirconia specimens were prepared from presintered monolithic zirconia blanks. All specimens were then assigned to 4 groups according to heating rate as Control, Group $15^{\circ}C$, Group $20^{\circ}C$, and Group $40^{\circ}C$. All groups were sintered according to heating rates with the sintering temperature of $1500^{\circ}C$, a holding time of 90 minutes and natural cooling. The phase composition was examined by XRD analysis, three-point bending test was conducted to examine the flexural strength, and Weibull analysis was conducted to determine weibull modulus and characteristic strength. Average grain sizes were determined by SEM analysis. One-way ANOVA test was performed at a significance level of 0.05. RESULTS. Only tetragonal phase characteristic peaks were determined on the surface of analyzed specimens. Differences among the average grain sizes of the groups were not statistically significant. The results of the three-point bending test revealed no significant differences among the flexural strength of the groups (P>.05). Weibull modulus of groups was ranging from 3.50 to 4.74. The highest and the lowest characteristic strength values were obtained in Group $20^{\circ}C$ and Control Group, respectively. CONCLUSION. Heating rate has no significant effect on the flexural strength of monolithic zirconia. Monolithic zirconia restorations can be produced in shorter sintering periods without affecting the flexural strength by modifying the heating rate.

• 한국음향학회지
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• 제42권6호
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• pp.511-518
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• 2023

수중 이동체의 시험평가 과정에서 정확한 거리 추정은 중요한 요소 가운데 하나이다. 특히, 도달 시간 값을 이용하여 거리를 추정하는 경우 상관 특성 등으로 인해 처프 신호인 Linear Frequency Modulation(LFM)과 같은 신호의 적용성이 높다. 하지만 이동성이 있는 도플러 천이 환경에서는 거리-도플러 커플링 효과로 인하여 측정 오류가 발생할 수 있다. 이에 본 논문에서는 거리-도플러 커플링 효과를 보상하여 도달 시간 값의 측정 오류를 감소시키는 신호를 제시한다. 제안된 신호는 2종류의 LFM 신호를 중첩하여 구성하였으며, 거리-도플러 커플링 효과를 최소화할 수 있다. 시뮬레이션을 통해 제안된 신호가 수중 이동체의 거리 추정에 있어서 거리-도플러 커플링 효과를 보상하여 도달 시간 값의 측정 오류를 줄이는 방법임을 확인하였다.

• 농업생명과학연구
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• 제50권3호
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• pp.1-11
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• 2016

3차원 지형정보를 얻기 위하여 항공 LiDAR(Light Detection and Ranging)자료 기반 수치표고모델(Digital Elevation Model, DEM) 생성에 대한 연구들에 대한 관심이 지속적으로 높아져 왔다. 항공 LiDAR 원자료로부터 정확도가 높은 DEM을 생성하기 위해서는 3차원 점군에서 비지면점을 제외시키고 지면점만을 포함시키는 필터링(filtering)과정이 중요하다. 특히, 필터링을 구성하는 알고리즘의 패러미터 값 변화에 따라 산출되는 결과물들에 차이가 발생하고 정확도에 영향을 준다. 따라서 본 연구는 화천, 양주, 경산 및 장흥 유역 대상지의 항공 LiDAR 자료로부터 Fusion 소프트웨어를 이용하여 LiDAR DEM을 생성하는 GroundFilter알고리즘의 Mean패러미터(GFmn) 수준 변화가 LiDAR DEM 결과물의 정확도에 어떤 영향을 주는지 분석하였다. GFmn 수준 변화에 따른 정확도에 대한 영향 여부를 분석하기 위해 일원배치분산분석을 실시하였고, 그 결과 GFmn의 수준 변화에 따라 정확도에 대한 영향이 유의미하게 나타났다(F-value: 4.915, p<0.01). 이 후 각각의 GFmn 수준들을 다른 수준들과 차이가 있는지 여부로 묶기 위하여 사후검정을 실시하였다. 사후분석을 통해 잔차의 평균 차이에 따라 '7, 5, 9, 3'과 '1' 두 집단으로 나뉘었다. 아울러 보다 정확한 해발고도를 표현하는 LiDAR DEM 생성하는데 적정 GFmn은 '7' 조건일 때로 나타났다. 이 연구를 통해 보다 정확한 해발고도를 표현하는 LiDAR DEM을 생성할 수 있는 패러미터 값을 제안하였다.

• 한국식품위생안전성학회지
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• 제27권1호
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• pp.74-80
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• 2012

어류는 두뇌발달에 중요한 영양소이기도 하지만 신경독인 메틸수은을 함유하고 있는 것으로 알려져 있다. 메틸수은은 임산부가 임신 중에 태아의 두뇌에 치명적인 손상을 유발하는 것으로 알려져 있다. 따라서 연구자들은 생선소비와 임산부 제대혈 중의 메틸수은 함량을 확인하기 위하여 통영지역 임산부 159명을 대상으로 2010년 10월부터 2011년 3월 사이에 임산부의 생선소비와 제대혈의 수은농도의 관계를 조사하였다. 어류소비 관련자료는 설문조사를 통하여 수집하였고 통계처리는 one way ANOVA 를 이용하였다. 조사에 참여한 임산부의 평균나이는 30.1세이었고 임산부 제대혈의 수은 함량은 0.01-14.80 ppb 범위에 평균 $2.69{\pm}2.50ppb$이었다. 제대혈의 평균 수은함량은 WHO 기준인 5.0 ppb를 초과하지는 않았지만 159명 중 17명(10.7%)이 WHO 기준을 초과하였다. 연령별로는 30세 이상이 0.01-14.8 ppb 범위, 평균 $3.18{\pm}2.74ppb$로 29세 이하에서 0-8.00 ppb 범위, 평균 $2.04{\pm}2.00ppb$ 보다 1.6배 높았으며 유의적 차이가 있었다. 이 연구에서 생선섭취가 제대혈의 수은농도에 영향을 미치는 것으로 나타났다. 1주일에 3회 이상 섭취군이 평균 $4.15{\pm}4.02ppb$로 주 1-2회 섭취군의 $2.63{\pm}2.22ppb$, 먹지 않는 군의 $1.60{\pm}1.44ppb$ 보다 2.6배와 1.6배 각각 높게 나타났으며 적게 먹는 군과 먹지 않는 군과의 사이에는 유의적 차이가 없었고, 많이 섭취하는 군과는 유의적 차이 (p < 0.05)가 있었다. 이상의 결과에서 제대혈의 수은 농도는 생선섭취량과 관련이 있는 것으로 판단되며 가임기 여성이나 임산부에게 생선섭취를 제한하는 것이 제대혈의 수은 농도를 낮출 수 있고 향후 있을지도 모를 신생아의 신경발달 장애나 뇌 신경학적 손상을 줄일 수 있는 방법이라고 생각되었다.

• 인간행동과 음악연구
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• 제2권1호
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• pp.67-85
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• 2005

The purpose of this study was to investigate the effect of music listening, autogenic training, and music-assisted autogenic training on the quality of life, physiological and psychological relaxation responses, and daily living in a population of migraine patients. Forty migraine patients, ranging 20 to 60 years, were referred to the researcher by their physicians and participated in the study. A convenience control-group pretest-posttest design was employed. The participants were randomly assigned to one of four groups: music listening (ML), autogenic training (AT), music-assisted autogenic training (MAT), or a control group participants, with n = 10 participants per group. The participants in experimental groups received four 30-minute sessions with an assigned treatment, once a week during a 4-week experiment period. The participants in the control group continued their regular medical treatment as prescribed by the doctor without receiving any other relaxation treatment. However, they were still aware of the research and their responsibilities for the study. The Migraine Assessment (MIDAS) and Migraine-Specific Quality of Life (MSQOL) questionnaire were used to investigate a migraine patients' quality of life collected before and after the 4-week experiment for all subjects. The physiological and psychological relaxation responses of migraine patients were measured by relaxation levels and forehead temperature recorded before and after each treatment session for the participants in three treatment conditions. The effect of the relaxation treatments on daily living of migraine patients was examined through the frequency and intensity of migraine headaches, and the amount of medication taken for migraine headaches during the 4-week experiment as recorded in participants' diary for all participants. The results found significant differences from pre- to posttest on the MIDAS, MSQOL, and relaxation levels while no significant was found among the groups. The analysis of forehead temperature showed no significant difference from pre- to posttest and among the groups. A one-way ANOVA was performed on the frequency, intensity, and amount of medication taken for migraine headaches during the 4-week experiment period. While results yielded no significant difference among the groups, the data indicate that the participants in the three treatment groups reported fewer migraine headaches, lower degrees of headache intensity, and less medication taken for migraine headaches than participants in the control group. A conclusion drawn from this study is that music listening itself as a relaxation treatment, or as an adjunct to other relaxation techniques can be effective in the treatment of migraine headaches.

• 수산경영론집
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• 제14권2호
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• pp.15-68
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• 1983

From the economic point of view the fishing port is the complex of installations on land, organized to serve the fishing fleet and its cargo, and is the main link in the production chain of all components of the fishing industry, with the aim of achieving the planned targets with the minimum cost. Fishing port investment decisions have had significant impact on the development aims of Korean fisheries. Fishing port investments in Korea are made mostly by public or semipublic port authorities. Such investments should be judged not purely on the basis of financial profitability but rather on the extent to which they serve the development aims of the fishing industry. This makes the economic appraisal process more complex and presents certain problems in correctly quantifying the economic costs and benefits of the fishing port projects. This study concentrates more on the theoretical economic appraisal models than on the purely financial aspects of fishing port investments and points out the difference between the two approaches. In the result, there is clearly an element of judgment as to whether or not a shadow price needs to be used in estimating economic benefits and costs. From this viewpoint, some attempts are made to provide definitions of the possible economic benefits and costs, and methods for estimating and evaluating them in Part III and IV. Especially queueing theory is applied in the calculation of economic benefits. When a project is contemplated and analysis shows it to Lave a positive NPV, one question that arises is whether it should be implemented now or delayed. In this paper, the first year rate of return method is regarded as a more concise way of solving the timing of investment, At the end of Part IV, risk analysis of fishing port investments is considered. It can be handled in a number of ways, ranging from informal judgment to complex statistical analyses involving large-scale computer models, This paper recommends that evaluators of fishing port investments use the sensitivity analysis indicating exactly how much NPV will change in response to a given change in an input variable, other things held constant. Decisions regarding the amount of capacity to provide must be made in fishing port investments. Providing too much service would involve excessive capital costs. On the other hand, not providing enough service capacity would cause the waiting line of fishing vessels to become excessively long at times. Therefore, in Part V, the optimal number of berths and berth productivity in fishing port are defined as follows: Minimize E(TC) ＝ E(WC)＋E(SC) The minimum of this function is the solution and that is the optimal number of berth and berth productivity in fishing port.

• World Technopolis Review
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• 제4권1호
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• pp.11-22
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• 2015

Globalization, increasing technological advancements and dynamic knowledge diffusion are moving our world closer together at a unique scale and pace. At the same time, our rapidly changing society is confronted with major challenges ranging from demographic to economic ones; challenges that necessitate highly innovative solutions, forcing us to reconsider the way that we actually innovate and create shared value. As such the linear, centralized innovation models of the past need to be replaced with new approaches; approaches that are based upon an open and collaborative, global network perspective where all innovation actors strategically network and collaborate, openly distribute their ideas and co-innovate/co-create in a global context utilizing our society's full innovation potential (Innovation 4.0 - Open Innovation 2.0). These emerging innovation paradigms create "an opportunity for a new entrepreneurial renaissance which can drive a Cambrian like explosion of sustainable wealth creation" (Curley 2013). Thus, in order to materialize this entrepreneurial renaissance, it is critical not only to value but also to actively employ this new innovation paradigms so as to derive community-driven shared value that stems from global innovation networks. This paper argues that there is a gap in existing business incubation model that needs to be filled, in that the innovation and entrepreneurship community cannot afford to ignore the emerging innovation paradigms and rely upon closed incubation models but has to adopt an "open incubation" (Ziouvelou 2013). The open incubation model is based on the principles of open innovation, crowdsourcing and co-creation of shared value and enables individual users and innovation stakeholders to strategically network, find collaborators and partners, co-create ideas and prototypes, share their ideas/prototypes and utilize the wisdom of the crowd to assess the value of these project ideas/prototypes, while at the same time find connections/partners, business and technical information, knowledge on start-up related topics, online tools, online content, open data and open educational material and most importantly access to capital and crowd-funding. By introducing a new incubation phase, namely the "interest phase", open incubation bridges the gap between entrepreneurial need and action and addresses the wantpreneurial needs during the innovation conception phase. In this context one such ecosystem that aligns fully with the open incubation model and theoretical approach, is the VOICE ecosystem. VOICE is an international, community-driven innovation and entrepreneurship ecosystem based on open innovation, crowdsourcing and co-creation principles that has no physical location as opposed to traditional business incubators. VOICE aims to tap into the collective intelligence of the crowd and turn their entrepreneurial interest or need into a collaborative project that will result into a prototype and to a successful "crowd-venture".

• The Journal of Advanced Prosthodontics
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• 제9권5호
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• pp.321-327
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• 2017

PURPOSE. The aim of this study was to investigate dental arch dimensions and to classify arch shape in Korean young adults. MATERIALS AND METHODS. The sample included 50 Koreans with age ranging from 24 to 32 years. Maxillary and mandibular casts were fabricated using irreversible hydrocolloid and type III dental stones. Incisor-canine distance, $incisor-1^{st}$ molar distance, $incisor-2^{nd}$ molar distance, intercanine distance, $inter-1^{st}$ molar distance, and $inter-2^{nd}$ molar distance in both the maxillary and mandibular arch were measured using a three-dimensional measuring device. The dental arch was classified into three groups using five ratios from the measured values by the K-means clustering method. The data were analyzed with one-way analysis of variance. RESULTS. Arch lengths (IM2D, $incisal-2^{nd}$ molar distance) were 44.13 mm in the maxilla and 40.40 mm in the mandible. Arch widths (M2W, inter $2^{nd}$ molar width) were 64.12 mm in the maxilla and 56.37 mm in the mandible. Distribution of the dental arch form was mostly ovoid shape (maxilla 52% and mandible 56%), followed by the V-shape and the U-shape. The arch width for the U-shape was broader than for the other forms. CONCLUSION. This study establishes new reference data for dental arch dimensions for young Korean adults. The most common arch form is the ovoid type in the maxilla and mandible of Koreans. Clinicians should be aware of these references and classify arch type before and during their dental treatment for effective and harmonized results in Koreans.

• 한국조리학회지
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• 제18권3호
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• pp.90-107
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• 2012

본 연구는 전통주의 소비시장을 세분화하고 관련 산업에 시사점을 제안하고자 전통주를 음용하는 외식 소비자를 대상으로 그들의 라이프스타일과 전통주 선택속성을 측정하여 그 차이를 규명하고 전통주 선택속성 중에서 구매만족에 미치는 변수를 찾는데 있다. 조사대상은 서울의 대도시 상권에 소재한 민속주점을 이용하고 있는 20대 이상의 성인으로 하였으며, 조사기간은 2010년 8월 1일부터 9월 30일까지 수행하였다. 분석결과, 전통주와 관련된 외식소비자의 라이프스타일은 사회형, 마니아형, 지식추구형, 문외형으로 분류되었고, 전통주 라이프스타일에 따른 소비자 그룹은 군집분석에 의해 전문가, 애호가, 초보자, 무관심자로 구분되었다. 그리고 전통주 선택속성은 전통주의 특성요인, 맛과 향요인, 대중성요인, 조화요인, 관심 요인 등 총 6개 요인으로 나타났다. 검증결과, 외식소비자의 라이프스타일과 분류된 소비자의 그룹 간에는 유의한 차이가 있는 것으로 조사되었고, 전통주 선택속성과의 차이점에도 유의한 것으로 나타났으며 소비자의 그룹에 따른 전통주에 대한 선택속성에도 유의한 차이가 있는 것으로 조사되었다. 마지막으로 전통주 선택속성은 구매만족에 부분적으로 영향관계에 있는 것으로 조사되었으며, 이중 맛과 향, 대중성이 긍정적인 정(+)의 관계에 있는 것으로 나타났다.

• Child Health Nursing Research
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• 제6권2호
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• pp.212-223
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• 2000

The purposes of this research were to add to the developing knowledge base about the burden and social support of grandmothers involved with caring grandchildren, and to examine whether a significant relationship exists between their burden and social support perceived by the grandmothers. A convenience sample of 102 grandmothers was recruited from five collective apartment areas at a small city in Korea. The criteria of selection of sample were that the grandmothers were raising their grandchildren under the age of 36 months for 3 months or longer at own or gandchildren's home. The instruments used were a 15-item multidemensional burden scale and a 8-item social support scale. Both scales were self report, five point Likert type scales. The higher the score, the higher the degree of burden and social support. Data was collected by two prepared research assistants visiting subjects' home from December 10, 1998 to March 20, 1999. The collected data were analysed using mean, t-test, one-way ANOVA, and Pearson's correlation coefficient computed by SPSS software. The results were as follows. 1. In the age distribution of grandmothers, the over half of subjects(58.8%) were under 60 years old. The majority(69.6%) of subjects were married at time of data collection. 79(77.5%) of the sample reported that their perceived health status was good or over. 2. The burden of the grandmothers was not scored high, and the item means on burden scale were ranged from 2.26 to 4.19 out of 5. 'Short of private time'(4.19) had the highest score, followed by 'fatigue'(3.92), 'short of rest'(3.75), and 'short of contact with friends and neighbors'(3.62). The lowest item was 'family doesn't help me'(2.26), and followed by 'family doesn't understand me'(2.33), 'angry with family' (2.43), and 'angry while caring for grandchild'(2.60). 3. There were significant relationships between the burden and present health status(p<.01), childcaring confidence(p<.01), and motive of caring(p<.01). 4. The score of social support, was ranging from 3.61 to 4.01 out of 5. 5. The relationship between burden and social support was found to be correlated negatively. The relationship was statistically significant(γ= - .2833, p<.001). In conclusion, it was found that the burden was not high and burden of grandmothers caring grandchildren was correlated negatively to social support. Therefore, these results provide a basis for developing a nursing intervention to reduce the burden of grandmothers.