• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권8호
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• pp.3683-3703
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• 2018

Wireless sensor networks (WSNs) consist of set of sensor nodes. These sensor nodes are deployed in unattended area which are able to sense, process and transmit data to the base station (BS). One of the primary issues of WSN is energy efficiency. In many existing clustering approaches, initial centroids of cluster heads (CHs) are chosen randomly and they form unbalanced clusters, results more energy consumption. In this paper, an energy efficient clustering protocol to prevent unbalanced clusters based on firefly and midpoint algorithms called EEC-FM has been proposed, where midpoint algorithm is used for initial centroid of CHs selection and firefly is used for cluster formation. Using residual energy and Euclidean distance as the parameters for appropriate cluster formation of the proposed approach produces balanced clusters to eventually balance the load of CHs and improve the network lifetime. Simulation result shows that the proposed method outperforms LEACH-B, BPK-means, Park's approach, Mk-means, and EECPK-means with respect to balancing of clusters, energy efficiency and network lifetime parameters. Simulation result also demonstrate that the proposed approach, EEC-FM protocol is 45% better than LEACH-B, 17.8% better than BPK-means protocol, 12.5% better than Park's approach, 9.1% better than Mk-means, and 5.8% better than EECPK-means protocol with respect to the parameter half energy consumption (HEC).

• 정보관리학회지
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• 제18권2호
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• pp.203-230
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• 2001

본 연구에서는 문헌을 기반으로 한 지식의 자동분류를 위해 최적의 클러스터링 모형을 제시하고자 하였다. 클러스터링 실험을 위해서 신문기사 실험집단과 학술논문 초록 실험집단을 구축하였고, 분류 성능 평가 척도인 WACS를 개발하였다. 분류자질로 사용한 용어의 집합은 다양한 자질 축소 기준을 적용하여 생성하였으며, 다양한 용어 가중치를 사용하였다. 유사계수 공식으로는 코사인 계수와 자카드 계수를 적용하였으며, 클러스터링 알고리즘으로는 비계층적 기법인 완전연결 기법과 계층적 기법인 K-means기법을 각각 사용하였다. 실험 결과 신문기사 원문 집단에서의 성능이 좋았으며, 완전연결 기법의 성능이 K-means 기법보다 높게 나타났다. 역문헌빈도의 적용은 완전연결 클러스터링에서는 긍정적인 효과가 나타났으나, K-means 클러스터링에서는 그렇지 못했다. 분류자질은 전체의 7.66%만 사용하였을 경우에도 성능 저하가 크지 않았으며, K-means 클러스터링에서는 오히려 성능 향상 효과가 있었다.

• 복식
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• 제24권
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• pp.157-176
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• 1995

The purpose of this treatise is to study external form and internal meaning of minimal expression fashion which appeared as a major stream in modern fashion trends to understand one aspect of modernism in fashion and also to gain insight into internal value of human beings through fashion. The results can be summarized as follows : Firstly , minimalism is a trend in art attempting to seek essence of the object by presenting simple and disciplined expressions by minimal formative means and minimal production process. Secondly, minimal expression in fashion means seeking simplicity an dpurity by using minimum design elements and minimal productive process. Thirdly, external from of minimal expression fashion can be created through application of following minimal expression techniques. 1. Minimal expression techniques in terms of line mean smooth curve flowing along body contours, straight lines of diagonal lines into desciplined silhouette or rendering internal contour lines. 2. Minimum expression techniques in terms of forms mean forms of smooth curves flowing along boyd or forms with simple geometric forms from qualitative aspects, In terms of volume it means quest for essence of pure body itself by revealing body as it is by minimizing the size of dress or its area and herein is contained using simple geometric pattern or utilizing textiles without any patterns.3. Minimal expression techniques by colors mean simple colors such as primary colors, colors without clear distinctions or natural colors and in terms of quantity it means quest for one color within one item of dress or combination of each items when getting dressed. 4. Minimal expression techniques in terms of fabrics mean fabrics with simple surfaced. In terms of quantity it means quest for essence of tight fitting thin textiles to human body or using transparent materials to human body thus exposing body contours as it is. 5. Minimal expression techniques in terms of productive process mean minimizing process of tailoring , sewing or ornamenting and seeking for simplicity and purity. 6. Minimal expression techniques in terms of manufacturing process mean selection of technique conveying simple image with disciplined simple image. Fourthly, minimal expression fashion with external expression as mentioned in the above lay body-priority style and its internal meaning can be asummed as quest for essence and purity of human body.

• 대한안전경영과학회지
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• 제17권2호
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• pp.215-228
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• 2015

A creative innovation and an innovative problem-solving of industrial companies can be achieved by overcoming the challenges of technical and physical contradictions. The approaches to address conflicting and paradoxical problems, such as technical and physical contradictions have a crucial role in advancing the quality assessment for manufacturer and service provider. The term, technical contradiction, depicts the state that improvement of one ends of IFR (Ideal Final Result) leads to unfavorable condition of the other ends, and results in conflicting problem. Another type of contradictions that's discussed in this study is a physical contradiction which is due to two mutually opposing states of the means of ends, and gives paradoxical situation. By integrating the means-ends chain perspectives, the physical contradiction that is a specifically root-causes, "means", can be initially addressed to resolve the downstream problem of technical contradiction which represents a general and abstract goals, "ends". This research suggests IFR resolution processes to handle both physical contradiction of means and technical contradiction of ends by employing causal relationship with IFR, effects and causes. In summary, the study represents three major processes that resolve such contradictions are demonstrated as follows: 1) Derivation of causal and hierarchical relationship among IFR, ends and means by considering CAED (Cause-And-Effect Diagram) and LT (Logic Tree). 2) Identification of causal relationship between physical contradiction and technical contradiction by using TPCT (TRIZ Physical Contradiction Tree) and TCD (Technical Contradiction Diagram). 3) Application of integrated TRIZ principles by classifying 40 inventive principles into 4 general conditions of the separation principle of mutually opposite states in space, in time, based on conditions, and between the parts and the whole. In order to validate the proof of proposed IFR resolution processes, the analysis of the TRIZ case studies from National Quality Circle Contest in the years, 2011 to 2014 have been proposed. The suggested guidelines that are built based on TRIZ principles can uniquely enhance the process of quality innovation and assessment for quality practitioners.

• 전기학회논문지
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• 제65권9호
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• pp.1557-1563
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• 2016

According to recent studies, poor sitting posture of the spine has been shown to lead to a variety of spinal disorders. For this reason, it is important to measure the sitting posture. We proposed a strategy for classification of sitting posture using machine learning. We retrieved acceleration data from single tri-axial accelerometer attached on the back of the subject's neck in 5-types of sitting posture. 6 subjects without any spinal disorder were participated in this experiment. Acceleration data were transformed to the feature vectors of principle component analysis. Support vector machine (SVM) and K-means clustering were used to classify sitting posture with the transformed feature vectors. To evaluate performance, we calculated the correct rate for each classification strategy. Although the correct rate of SVM in sitting back arch was lower than that of K-means clustering by 2.0%, SVM's correct rate was higher by 1.3%, 5.2%, 16.6%, 7.1% in a normal posture, sitting front arch, sitting cross-legged, sitting leaning right, respectively. In conclusion, the overall correction rates were 94.5% and 88.84% in SVM and K-means clustering respectively, which means that SVM have more advantage than K-means method for classification of sitting posture.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.104-107
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• 2019

현대인들은 과거에 비해 풍부한 먹거리와 다양한 삶의 형태를 가지게 되었으나 바쁜 생활 속에 아침을 거르게 되고, 제 시간에 식사를 하지 못하는 등의 올바르지 못한 식습관을 형성하게 되었다. 이러한 식습관은 장기간 유지되면서 소화기관 장애로 이어지게 된다. 그에 가장 쉽게 발생하는 증상이 역류성 식도염과 삼킴 장애라고 불리는 연하 곤란이 있으며, 그 중 연하 곤란은 다양한 합병증의 형태로 발전하거나 위암, 후두암등의 전조증상으로 확인되기도 하여 빠르고 정확한 진단이 요구된다. 이에 따른 진단 결과는 현재도 의사가 수동적으로 판단하며 그 결과가 제각각이다. 여기서 말하는 진단 결과는 중증 정도를 말하는 것이며, 그에 따른 치료법이나 합병증을 파악할 때의 잘못된 진단으로 과한 치료나 부족한 대처로 이어지게 될 수도 있다. 본 논문에서는 연하 곤란의 심각 정도를 파악하기 위해 연하 곤란 진단 과정에서 식도로 이어지는 구간에 후두개곡과 이상와 부에 남는 잔여 음식물을 확인하기 위한 X-ray 이미지 처리에 K-means 알고리즘을 사용하는 프로그램을 개발하는 것을 연구하였다.

• 한국통신학회논문지
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• 제29권5C호
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• pp.627-631
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• 2004

음성인식 모델상의 GPDFs(Gaussian Probability Density Functions)을 효율적으로 군집화 할 수 있는 알고리즘이 제안되었다. 제안된 알고리즘은 데이터 사이의 거리 척도로 발산 거리를 사용하는 새로운 형태의 CNN(Centroid Neural Network)으로, 제한된 자원을 가지는 H/W환경의 음성인식에서 메모리 사용량을 축소하는 응용에 대한 실험 결과, 음성인식 모델인 CDHMM(Continuous Density Hidden Markov Model)에서 기존의 Dk-means(Divergence-based k-means)알고리즘을 이용한 방법과 비교하여 인식 성능의 유지와 함께 약 31.3％의 GPDFs를 더 축소할 수 있었고, 군집화 알고리즘을 적용하지 자은 전체 GPDFs를 사용한 경우와 비교해서 인식 성능의 유지와 함께 약 61.8％의 GPDFs를 압축할 수 있었으며, SNR 10㏈ 잡음 데이터에 대한 성능평가에서도 인식 성능이 유지될 수 있었다.

• 동력기계공학회지
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• 제20권4호
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• pp.32-37
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• 2016

This paper proposes two measurement methods for injured rate of fish surface using color image segmentation method based on K-means clustering algorithm and Otsu's threshold algorithm. To do this task, the following steps are done. Firstly, an RGB color image of the fish is obtained by the CCD color camera and then converted from RGB to HSI. Secondly, the S channel is extracted from HSI color space. Thirdly, by applying the K-means clustering algorithm to the HSI color space and applying the Otsu's threshold algorithm to the S channel of HSI color space, the binary images are obtained. Fourthly, morphological processes such as dilation and erosion, etc. are applied to the binary image. Fifthly, to count the number of pixels, the connected-component labeling is adopted and the defined injured rate is gotten by calculating the pixels on the labeled images. Finally, to compare the performances of the proposed two measurement methods based on the K-means clustering algorithm and the Otsu's threshold algorithm, the edge detection of the final binary image after morphological processing is done and matched with the gray image of the original RGB image obtained by CCD camera. The results show that the detected edge of injured part by the K-means clustering algorithm is more close to real injured edge than that by the Otsu' threshold algorithm.

• 한국인터넷방송통신학회논문지
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• 제18권6호
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• pp.259-268
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• 2018

본 연구의 목적은 인지기능 훈련 콘텐츠들을 사용하는 동안 사용자들의 흥미와 몰입도를 높이기 위하여 인지 능력 수준에 맞춘 훈련 방법을 제시하는 것이다. 사용자의 인지 능력 수준은 K-means 알고리즘을 적용한 협업 필터링을 사용하여 사용자들의 정보와 한국형 아동 간이 정신 상태 검사 점수를 기반으로 군집화한 결과를 바탕으로 이루어졌다. 이 결과를 구현된 인지기능 훈련 통합 시스템에 적용하여 사용자의 인지 능력 수준에 알맞은 인지기능 훈련 영역 별 콘텐츠 순서와 난이도를 추천하였다. 특히 콘텐츠 난이도 조절은 사용자들이 긴장감과 편안함을 반복적으로 느낄 수 있도록 제안한 '몰입이론' 방법을 적용하여 높은 몰입감을 주고자 하였다. 결론적으로 본 논문에서 제안한 사용자 맞춤형 인지기능 훈련 방법은 기존의 치료사가 콘텐츠 순서와 난이도를 주관적으로 설정하는 것보다 더욱 효과적이고 재활 결과를 기대할 수 있을 것이다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.162-167
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• 2005

Recently, the advanced industries using micro parts are rapidly growing. Micro endmilling is one of the prominent technology that has wide spectrum of application field ranging from macro to micro parts. Also, the method of micro-grooving using micro endmilling is used widely owing to many merit, but has problems of precision and quality of products due to tool wear and tool fracture. This study deals with condition monitoring using acoustic emission(AE) signal in the micro-grooving. First, the feature extraction of AE signal directly related to machining process is executed. Then, the distinctive micro endmill state according to the each tool condition is classified by using the fuzzy C-means algorithm, which is one of the methods to recognize data patterns. These result is effective monitoring method of micro endmill state by the AE sensing techniques which can be expected to be applicable to micro machining processes in the future.