An Efficient Genetic Algorithm for Maximum Coverage Deployment in Wireless Sensor Networks

Yourim Yoon,Yong-Hyuk Kim IEEE 2013 IEEE transactions on cybernetics Vol.43 No.5

<P>Sensor networks have a lot of applications such as battlefield surveillance, environmental monitoring, and industrial diagnostics. Coverage is one of the most important performance metrics for sensor networks since it reflects how well a sensor field is monitored. In this paper, we introduce the maximum coverage deployment problem in wireless sensor networks and analyze the properties of the problem and its solution space. Random deployment is the simplest way to deploy sensor nodes but may cause unbalanced deployment and therefore, we need a more intelligent way for sensor deployment. We found that the phenotype space of the problem is a quotient space of the genotype space in a mathematical view. Based on this property, we propose an efficient genetic algorithm using a novel normalization method. A Monte Carlo method is adopted to design an efficient evaluation function, and its computation time is decreased without loss of solution quality using a method that starts from a small number of random samples and gradually increases the number for subsequent generations. The proposed genetic algorithms could be further improved by combining with a well-designed local search. The performance of the proposed genetic algorithm is shown by a comparative experimental study. When compared with random deployment and existing methods, our genetic algorithm was not only about twice faster, but also showed significant performance improvement in quality.</P>

Effect of particle size of plant-based protein ink on the texture of 3D printed alternative meat

Yourim Oh,Nam Keun Lee,Jin-Kyu Rhee 한국식품영양과학회 2022 한국식품영양과학회 학술대회발표집 Vol.2022 No.10

Characterization of Food Microstructure Produced with 3D Printer

Yourim Oh,Hyeona Kang,Jeong Bin Bae,Soyeong Jeong,Nam Keun Lee,Jin-Kyu Rhee 한국식품영양과학회 2019 한국식품영양과학회 학술대회발표집 Vol.2019 No.10

Private School Effects in Korea:Trends in Mean and Dispersion Difference

Yourim Chai(최유림) 한국인구학회 2015 한국인구학 Vol.38 No.2

본 연구는 한국의 사립학교가 공립학교보다 평균적으로 학업성취에 있어 우세한지, 그리고 학교간 학업성취 차이가 공립학교와 사립학교에서 어떻게 다르게 나타나는지를 탐구한다. 사립학교 효과 연구는 미국 교육사회학의 주요한 주제이며 이를 분석하기 위한 다양한 방법이 고안되어 왔다. 한국에서도 여러 연구를 통해 한국의 사립학교 효과 유무에 대해 논의되고 있다. 그러나 자료와 통계 방법에 따라 상이한 결과를 보이고 있다. 본 연구는 이를 위해 1999년에서 2012년까지의 대학수학능력시험 점수를 3수준 다층모형을 통해 분석하였다. 사립학교 효과의 인과관계를 분석하기 위해 평준화 지역으로 분석 대상을 한정하였으며, 평준화 지역 일반계 고등학교 모집단의 80%에 이르는 표본을 가지고 분석하였다. 분석 결과, 공사립학교 간 평균점수의 차이는 통계적으로 유의미하지 않았으나, 성적의 학교간 분산이 사립학교에서 더 크게 나타났으며 이러한 경향은 시간이 갈수록 더 강하게 나타났다. 이는 정부의 고등학교 다양화 정책에 따라, 사립학교간 학교 편차가 공립학교간 학교 편차보다 커지고 있음을 시사한다. 결론에서 사립학교의 어떠한 특성이 이를 가능하게 했는지에 대해 간단히 논의하였다. The current study examines private school effects on students’ academic achievements in Korea, between 1999 and 2012. I use the College Scholastic Ability Test (CSAT) (1999~2012) by applying a multi-level regression analysis. I analyze students who attended schools to which Equalization Policy applied to estimate causal private school effects. The analyses showed the followings. There was little private school advantage in students’ academic achievements on average. Despite little private school effect, private schools were much more heterogeneous than public schools in affecting students’ outcomes. Furthermore, sector differences in school-level heterogeneity tend to increase over time. I interpret this diverging trend as a consequence of sector differences in responses to changing educational policies that emphasized diversity of educational opportunity. These findings suggest that more research should explore different school-level characteristics to understand differences in educational settings between school sectors.

Neurophysiological and Psychological Predictors of Social Functioning in Patients with Schizophrenia and Bipolar Disorder

Yourim Kim,Aeran Kwon,Dongil Min,Sungkean Kim,Min Jin Jin,Seung-Hwan Lee 대한신경정신의학회 2019 PSYCHIATRY INVESTIGATION Vol.16 No.10

psychological and neurophysiological predictors of social functioning. Methods Twenty-seven patients with schizophrenia and thirty patients with bipolar disorder, as well as twenty-five healthy controls, completed measures of social functioning (questionnaire of social functioning), neurocognition (Verbal fluency, Korean-Auditory Verbal Learning Test), and social cognition (basic empathy scale and Social Attribution Task-Multiple Choice), and the childhood trauma questionnaire (CTQ). For neurophysiological measurements, mismatch negativity and heart rate variability (HRV) were recorded from all participants. Multiple hierarchical regression was performed to explore the impact of factors on social functioning. Results The results showed that CTQ-emotional neglect significantly predicted social functioning in schizophrenia group, while HRVhigh frequency significantly predicted social functioning in bipolar disorder patients. Furthermore, emotional neglect and HRV-HF still predicted social functioning in all of the subjects after controlling for the diagnostic criteria. Conclusion Our results implicated that even though each group has different predictors of social functioning, early traumatic events and HRV could be important indicators of functional outcome irrespective of what group they are.

Quotient geometric crossovers and redundant encodings

Yoon, Yourim,Kim, Yong-Hyuk,Moraglio, Alberto,Moon, Byung-Ro Elsevier 2012 Theoretical computer science Vol.425 No.-

<P><B>Abstract</B></P><P>We extend a geometric framework for the interpretation of search operators to encompass the genotype–phenotype mapping derived from an equivalence relation defined by an isometry group. We show that this mapping can be naturally interpreted using the concept of quotient space, in which the original space corresponds to the genotype space and the quotient space corresponds to the phenotype space. Using this characterization, it is possible to define induced geometric crossovers on the phenotype space (called <I>quotient geometric crossovers</I>). These crossovers have very appealing properties for non-synonymously redundant encodings, such as reducing the size of the search space actually searched, removing the low locality from the encodings, and allowing a more informed search by utilizing distances better tailored to the specific solution interpretation. Interestingly, quotient geometric crossovers act on genotypes but have an effect equivalent to geometric crossovers acting directly on the phenotype space. This property allows us to actually implement them even when phenotypes cannot be represented directly. We give four example applications of quotient geometric crossovers for non-synonymously redundant encodings and demonstrate their superiority experimentally.</P>

최대 커버리지 센서 배치를 위한 유전 알고리즘

윤유림(Yourim Yoon),김용혁(Yong-Hyuk Kim) 한국지능시스템학회 2010 한국지능시스템학회논문지 Vol.20 No.3

본 논문에서는 실세계에서 센서를 배치할 때 발생하는 최적화 문제인 최대 커버리지 센서 배치 문제를 정의하고 문제의해 공간의 특성을 분석하였다. 또한 최대 커버리지 센서 배치 문제의 좋은 해를 얻기 위해 유전 알고리즘을 설계하고 그 우수성을 비교 실험을 통해 보였다. 이 문제에 유전 알고리즘을 적용할 때 중요하게 고려되어야 할 부분은 평가 함수를 어떻게 구현하느냐 인데 몬테카를로법을 통해 해결할 수 있었다. 유전 알고리즘의 몬테카를로법을 이용한 평가 부분에서 샘플 생성 횟수를 조절함으로써 동일한 성능을 내면서 계산 시간을 크게 줄일 수 있었다. In this paper, we formally define the problem of maximizing the coverage of sensor deployment, which is the optimization problem appeared in real-world sensor deployment, and analyze the properties of its solution space. To solve the problem, we proposed novel genetic algorithms, and we could show their superiority through experiments. When applying genetic algorithms to maximum coverage sensor deployment, the most important issue is how we evaluate the given sensor deployment efficiently. We could resolve the difficulty by using Monte Carlo method. By regulating the number of generated samples in the Monte Carlo evaluation of genetic algorithms, we could also reduce the computing time significantly without loss of solution quality.

미용교육의 상호작용적 특성과 지각된가치 및 팬쉽의 관계

이유림 ( Yourim Lee ),김지영 ( Jiyeong Kim ),서예지 ( Yeji Suh ),박은준 ( Eun-jun Pack ) 한국미용학회 2021 한국미용학회지 Vol.27 No.3

The improved economic level has led to the development of the leisure culture of people, and various human needs based on leisure have been expressed. In response, the purpose of this study is to present practical implications related to the importance of learning transfer through communication and trust for the qualitative growth of beauty education, by examining the effect of learner-educator interaction characteristics and students' perceived value on fanship as a beauty educator. For empirical analysis, a self-report survey was conducted on students who had recently taken beauty education, and a total of 506 questionnaires collected from March 4, 2020 to April 24, 2020 (52 days in total) were used as the final analysis data. Through the SPSS 22.0 program, frequency analysis, factor analysis, reliability analysis, and regression analysis were conducted. The main results of this study for beauty trainees are as follows. The main results of this study based on a total of 506 beauty education students are summarized as follows. First, the result of examining the demographic characteristics of the survey subjects showed that the gender and age of beauty education students were women in their 20s and younger. Also, less than a year of total work experience and a monthly average salary of 1 to 2 million Korean won had the highest percentages. Second, according to the result of regression analysis on the effect of interactive characteristics on perceived value, perceived value was significantly influenced by the factors such as receptivity, sensitivity, cognitive involvement, and the accessibility of interactive characteristics. In addition, the influence appeared in the order of receptivity, sensitivity, and cognitive involvement. Third, the result of regression analysis on the influence of interactive characteristics on fanship showed that all sub-elements of interactive characteristics had a positive effect on fanship. Fourth, as a result of regression analysis on the effect of perceived value on fanship, all sub-elements of perceived value had a positive effect on fanship. The study findings demonstrated that the close interaction between students and educators in beauty education and the perceived values of the students can form a positive fanship for beauty educators. This means that beauty education must not only consist of transferring knowledge but also establish a social relationship with students through empathy and communication with them. This implies that rather than giving beauty education to simply cultivate students' knowledge in their major, it is necessary to connect it to an individual's self growth so that the beauty education perceived by them becomes more valuable and meaningful in life.

A Memetic Lagrangian Heuristic for the 0-1 Multidimensional Knapsack Problem

Yoon, Yourim,Kim, Yong-Hyuk Hindawi Limited 2013 Discrete dynamics in nature and society Vol.2013 No.-

<P>We present a new evolutionary algorithm to solve the 0-1 multidimensional knapsack problem. We tackle the problem using duality concept, differently from traditional approaches. Our method is based on Lagrangian relaxation. Lagrange multipliers transform the problem, keeping the optimality as well as decreasing the complexity. However, it is not easy to find Lagrange multipliers nearest to the capacity constraints of the problem. Through empirical investigation of Lagrangian space, we can see the potentiality of using a memetic algorithm. So we use a memetic algorithm to find the optimal Lagrange multipliers. We show the efficiency of the proposed method by the experiments on well-known benchmark data.</P>

다중 배낭 문제를 위한 라그랑지안 휴리스틱

윤유림(Yourim Yoon),김용혁(Yong-Hyuk Kim) 한국지능시스템학회 2010 한국지능시스템학회논문지 Vol.20 No.6

일반적으로 이산 최적화에서의 라그랑지안 방법은 제약조건을 쉽게 다루기 위한 기법이다. 이 방법은 전형적으로 분지한계법에서 상한을 찾을 때 사용한다. 본 논문은 여러 개의 제약조건이 있는 다중 배낭 문제를 위한 새로운 라그랑지안 방법을 제안한다. 기존 라그랑지안 접근법과는 달리 제안한 방법은 라그랑지안 벡터의 새로운 특징에 기초하여 품질 좋은 하한 (즉, 가능 해)을 효율적으로 찾을 수 있다. 잘 알려진 큰 규모의 벤치마크 데이터에서 실험을 하였고 제안한 라그랑지안 방법은 기존 방법의 성능을 개선하였다. In general, Lagrangian method for discrete optimization is a kind of technique to easily manage constraints. It is traditionally used for finding upper bounds in the branch-and-bound method. In this paper, we propose a new Lagrangian search method for the 0-1 knapsack problem with multiple constraints. A novel feature of the proposed method different from existing Lagrangian approaches is that it can find high-quality lower bounds, i.e., feasible solutions, efficiently based on a new property of Lagrangian vector. We show the performance improvement of the proposed Lagrangian method over existing ones through experiments on well-known large scale benchmark data.