• 제목/요약/키워드: self-scaling

검색결과 194건 처리시간 0.024초

Small creatures can lift more than their own bodyweight and a human cannot-an explanation through structural mechanics

  • Balamonica, K;Jothi Saravanan, T.;Bharathi Priya, C.;Gopalakrishnan, N.
    • Biomaterials and Biomechanics in Bioengineering
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    • 제4권1호
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    • pp.9-20
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    • 2019
  • Living beings are formed of advanced biological and mechanical systems which exist for millions of years. It is known that various animals and insects right from small ants to huge whales have different weight carrying capacities, which is generally expressed as a ratio of their own bodyweights i.e., Strength to Bodyweight Ratio (SBR). The puzzle is that when a rhinoceros beetle (scientific name: Dynastinae) can carry 850 times its own bodyweight, why a man cannot accomplish the same feat. There are intrinsic biological and mechanical reasons related to their capacities, as per biomechanics. Yet, there are underlining principles of engineering and structural mechanics which tend to solve this puzzle. The paper attempts to give a plausible answer for this puzzle through structural mechanics and experimental modeling techniques. It is based on the fact that smaller an animal or creature, it has larger value of weight lifting by self-weight ratio. The simple example of steel prism model discussed in this paper, show that smaller the physical model size, larger is its SBR value. To normalize this, the basic length of the model need to be considered and when multiplied with SBR, a constant is arrived. Hence, the aim of the research presented is to derive this constant on a pan-living being spectrum through size/scaling effect.

차세대 지능형 소자 구현을 위한 모노리식 3D 집적화 기술 이슈 (Issues on Monolithic 3D Integration Techniques for Realizing Next Generation Intelligent Devices)

  • 문제현;남수지;주철웅;성치훈;김희옥;조성행;박찬우
    • 전자통신동향분석
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    • 제36권3호
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    • pp.12-22
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    • 2021
  • Since the technical realization of self-aligned planar complementary metal-oxide-semiconductor field-effect transistors in 1960s, semiconductor manufacturing has aggressively pursued scaling that fruitfully resulted in tremendous advancement in device performances and realization of features sizes smaller than 10 nm. Due to many intrinsic material and technical obstacles, continuing the scaling progress of semiconductor devices has become increasingly arduous. As an effort to circumvent the areal limit, stacking devices in a three-dimensional fashion has been suggested. This approach is commonly called monolithic three-dimensional (M3D) integration. In this work, we examined technical issues that need to be addressed and overcome to fully realize energy efficiency, short latency and cost competency. Full-fledged M3D technologies are expected to contribute to various new fields of artificial intelligence, autonomous gadgets and unknowns, which are to be discovered.

t-SNE에 대한 요약 (A review on the t-distributed stochastic neighbors embedding)

  • 김기풍;김충락
    • 응용통계연구
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    • 제36권2호
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    • pp.167-173
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    • 2023
  • 본 논문에서는 고차원의 자료를 저차원으로 변환시켜 시각화하는 다양한 방법들을 소개하였다. 차원 축소는 크게 선형 방법과 비선형 방법으로 나눌 수 있는데 선형 방법으로 주성분 분석, 다차원 척도 등을 간략하게 소개하였고 비선형 방법으로 커널 주성분 분석, 자기조직도, 국소 선형 사상, Isomap, 국소 다차원 척도 등을 간략하게 소개하였으며, 가장 최근에 제안되었으며 매우 널리 사용되고 있지만 통계학 분야에는 비교적 생소한 t-SNE에 대하여 자세히 소개하였다. t-SNE를 이용한 간단한 예제를 제시하고 t-SNE의 장단점을 지적한 최근 연구 논문을 소개하고 제시된 향후 연구 과제들을 살펴보았다.

자기 아파인 프랙탈 구조를 이용한 CPW 급전 크로스 안테나 (A CPW-Fed Self-Affine Cross Shape Fractal Antenna)

  • 김태환;이재욱;조춘식;이윤현
    • 한국전자파학회논문지
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    • 제16권9호
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    • pp.949-956
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    • 2005
  • 본 논문에서는 처음으로, CPW(CoPlanar Waveguide) 급전을 이용한 자기 아파인(self-affine) 프랙탈 안테나를 제시한다. 제시된 새로운 구조는 비등방성 축척 대칭성으로 인해 자기 상사(self-similar) 구조를 이용한 프랙탈 안테나보다 더 작은 크기로 낮은 주파수 대역에서 공진을 일으키도록 설계할 수 있다. 반복 계수가 증가할수록 임피던스 정합 조건이 향상되고, 표면 전류가 흐를 수 있는 새로운 통로를 만들어 다중 대역 특성을 보이게 되며, 또한 첫 공진 주파수의 위치를 낮은 쪽으로 이동시킨다. 복사 패턴은 목표치인 단순 모노폴 안테나 특성과 유사하며 반복 계수가 3일 때의 이득은 940 MHz에서 측정치 2.27 dBi로 최대이다. FDTD 알고리즘에 기반을 두고 있는 CST Microwave Studio를 이용한 모의 실험 결과와 RT/Duroid 5880 기판을 이용하여 제작한 안테나의 측정 결과를 싣는다.

DVB-S2 기반 고속 LDPC 복호를 위한 효율적인 CNU 계산방식에 관한 연구 (A Study on Efficient CNU Algorithm for High Speed LDPC decoding in DVB-S2)

  • 임병수;김민혁;정지원
    • 한국정보통신학회논문지
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    • 제16권9호
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    • pp.1892-1897
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    • 2012
  • 본 논문은 DVB-S2 기반 고속 LDPC 복호를 하기 위한 효율적인 CNU(Check Node Update) 계산방식에 대해 분석하였다. LDPC의 복호 속도는 CNU 계산 과정에 의존한다. 기존의 CNU 계산방식에서 LUT를 고려한 SP(Sum-Product)방식은 속도가 늦어지는 단점이 있다. 이에 본 논문에서는 SC-NMS(Self-Corrected Normalized Min-Sum) 방식을 제안한다. LUT 연산을 제거한 MS(Min-Sum) 방식에 정규화 계수 '${\alpha}$'를 곱하는 Normalized Min-Sum(NMS) 방식은 MP 방식보다 성능은 약간 감소하지만 critical path를 없애고 클럭 주기를 줄일 수 있어 구현에 있어서 고속화를 위한 효율적인 CNU 계산방식이다. 또한, 복호과정에서 반복 시 이전 반복에서의 엣지 값과 현재 반복에서의 엣지 값을 비교하여 부호가 바뀌면 신뢰성이 없음을 간주하여 현재 엣지에 "0"을 할당하는 SC(Self-Corrected) 방식을 연구하였다. SC-NMS 방식을 적용하여 시뮬레이션 한 결과, SC-NMS 방식은 SP 방식에 비해 0.1dB의 성능열화를 보였지만, 계산의 복잡도와 복호 속도를 고려했을 때, SC-NMS 방식이 최적의 CNU 계산 방식이라는 것을 확인하였다.

구강위생상태의 개선을 위한 자가검사법의 효과 (Effect of Self-Testing Technique on Improvement of Oral Hygiene State)

  • 김종엽;박준봉;이만섭;권영혁;허익
    • Journal of Periodontal and Implant Science
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    • 제29권3호
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    • pp.715-724
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    • 1999
  • The purpose of this study was to approve the possibility of clinical application of selftesting technique to confirm the cleanness status of the tooth surface after mechanical toothbrushing. Thirty-two periodontal patients who did not compromise any other systemic diseases were divided into two groups. Control group was instructed only the Bass method for toothbrushing, and then experimental group was demonstrated the Bass method and self-testing technique respectively for plaque control during this experiment. Selftesting technique is composed the comparison of roughness of the labial surface of maxillary central incisor and other toothsurface with touch sense using the tip of tongue. Plaque score and Gingival index were measured as clinical parameters at baseline and 1, 2 and 4 weeks after scaling and root planing. The results were as follows ; 1. Plaque scores and gingival index of 1, 2, and 4 weeks of two groups were statistically significant differences when compared with baseline value (p<0.05). 2. Plaque scores and gingival index of baseline and 1 week between two groups were not significant differences (p<0.05). 3. Plaque scores and gingival index of 2 and 4 weeks of test group were statistically significant difference when compared with control group (p<0.05). From the above results, self-testing technique which decides necessity of additional toothbrushing when tongue tip of subjects touch the maxillary molar buccal surfaces and mandibular molar lingual surfaces nd compares with maxillary anterior labial surfaces after toothbrushing appeared to effect the motivation of subjects. This study suggests that self-testing technique for cleanness after toothbrushing should be effect on the maintenance of oral hygiene when it is applied to clinical practice.

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3-D Hetero-Integration Technologies for Multifunctional Convergence Systems

  • 이강욱
    • 마이크로전자및패키징학회지
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    • 제22권2호
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    • pp.11-19
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    • 2015
  • Since CMOS device scaling has stalled, three-dimensional (3-D) integration allows extending Moore's law to ever high density, higher functionality, higher performance, and more diversed materials and devices to be integrated with lower cost. 3-D integration has many benefits such as increased multi-functionality, increased performance, increased data bandwidth, reduced power, small form factor, reduced packaging volume, because it vertically stacks multiple materials, technologies, and functional components such as processor, memory, sensors, logic, analog, and power ICs into one stacked chip. Anticipated applications start with memory, handheld devices, and high-performance computers and especially extend to multifunctional convengence systems such as cloud networking for internet of things, exascale computing for big data server, electrical vehicle system for future automotive, radioactivity safety system, energy harvesting system and, wireless implantable medical system by flexible heterogeneous integrations involving CMOS, MEMS, sensors and photonic circuits. However, heterogeneous integration of different functional devices has many technical challenges owing to various types of size, thickness, and substrate of different functional devices, because they were fabricated by different technologies. This paper describes new 3-D heterogeneous integration technologies of chip self-assembling stacking and 3-D heterogeneous opto-electronics integration, backside TSV fabrication developed by Tohoku University for multifunctional convergence systems. The paper introduce a high speed sensing, highly parallel processing image sensor system comprising a 3-D stacked image sensor with extremely fast signal sensing and processing speed and a 3-D stacked microprocessor with a self-test and self-repair function for autonomous driving assist fabricated by 3-D heterogeneous integration technologies.

일부 보건계열 대학생들의 구강건강관련 삶의 질에 영향을 미치는 요인 (Factors influencing oral health-related quality of life in health allied college students)

  • 박희정;이준협
    • 한국학교ㆍ지역보건교육학회지
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    • 제14권3호
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    • pp.1-14
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    • 2013
  • Objectives: The purpose of this study was to investigate the possible impact factors(oral health level, oral health promotion behaviors, health level, health behaviors, and mental health) on oral health related quality of life using OHIP-14 of health allied college students. Methods: A total of 363 self-administered questionnaires were collected from university student in Seoul. To investigate the casual relationship between each variable presented in the research model, descriptive statistics, t-test, one-way ANOVA(Scheffe's test), man-whitney, kruskal wallis, multiple regression analysis were carried out by using SPSS ver. 21.0 Results: The study shows that the students reported mean score of OHIP-14 ($8.32{\pm}7.51$), of which physical pain was the highest score($1.88{\pm}1.45$) and social disability was the lowest score($0.69{\pm}1.13$). Multiple regression revealed that the score of OHIP-14 was shown to be significantly higher for the following people: who were get more self-reported symptom of periodontitis, halitosis, negative self-perceived general health and oral health, no received dental scaling treatment, and participants who had no experience awareness of distress in two weeks. The explanatory power was 18.2%. The most powerful factor regarding to self-reported symptom of periodontitis was shown to be negatively relations oral health-related quality of life. Conclusions: In order to enhance the students' life quality, there need to be considered for a comprehensive oral health-related quality of life program for the students through health education policy.

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중·고등학생의 구강건강신념이 구강건강관리행동에 미치는 영향: 건강신념모형을 적용하여 (The impact of health belief model in the middle and high school students on oral health behaviors)

  • 임희정;김형주;안용순
    • 한국치위생학회지
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    • 제15권1호
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    • pp.111-118
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    • 2015
  • Objectives: The aim of the study is to investigate the health belief model affecting the oral health behavior in middle and high school students. Methods: The subjects were 296 middle and high school students in Seoul, Gyeonggi and Incheon from February 15 to March 21, 2014. The students filled out the self-reported questionnaires after receiving informed consents. The instrument was adopted and revised from those of Kim & Hwang, and Choi & Joo. The questionnaire consisted of 4 questions of general characteristics, 9 questions of oral health status including subjective oral health status, frequency of tooth brushing, duration of tooth brushing, method of tooth brushing, use of oral health devices, dental clinic visit, scaling services, snack intake, and smoking. The oral health belief consisted of 25 questions including susceptibility, seriousness, barriers, benefit, and self-efficacy using Likert 5 scale. The reliability of Cronbach's alpha in the study was 0.725. Data were analyzed using SPSS ver 18.0 for frequency analysis, t-test, ANOVA, ${\chi}^2$-test, and Pearson's correlation coefficient, simple regression, and binary logistic regression. Results: Oral health beliefs of middle and high school students affected the oral health behaviors. Susceptibility, barriers and self-efficacy also influenced on the oral health behaviors. In order to provide the best oral health education, susceptibility and self-efficacy are the primary factors to increase motivation because the motivation endows the students with correction of oral health behaviors that improve the knowledge, attitudes, and decrease barriers in oral hygiene. Conclusions: It is important to correct oral health behaviors in the middle and high school students by providing the continuing and systematic oral health education.

공간디자인에 적용된 프랙탈 특성의 인지생태론적 효과 - 랜드스케이프 패턴을 중심으로 - (Fractal Properties and Cognitive Ecological effects in Space Design - Focused on Landscape Pattern -)

  • 김주미
    • 한국실내디자인학회논문집
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    • 제20권2호
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    • pp.120-130
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    • 2011
  • The purpose of this study is to propose cognitive ecological effects of fractal patterns in space design. This study investigated the perception and cognition problems regarding landscape patterns showing fractal properties from the cognitive perspective instead of the traditional speculative approach. In particular, the researcher has verified that fractal geometry theory and fractal pattern concept provide insight in space aesthetic values and cognitive effects. Research results are as follows. First, most environmentally-friendly fractal urban forms provide cognitive connectivity. In particular, this space provides a positive emotional response and preference to humans and displays self-organized complexity. This study found that such complexity of space form has characteristics corresponding to parallel cognitive structures of the human brain. Simultaneously, the researcher suggests that the fractal landscape pattern is an alternative for stiff and homogenized modern space. Second, fractal patterns provide hierarchical connectivity within the brain through continuous difference and repetition. In particular, self-similarities of fractal patterns administer significant visual grouping and coherence in human perception. It can be determined whether scaling coherence facilitates easier organization in cognitive organization. Third, fractal patterns in space design provide the basic method for achieving the connection between concept, construction, and urban factors. As a result, the researcher has suggested that scale distribution of geometrical factors, such as fractal patterns, an be a design method to connect various space typologies.