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Intrinsic Enrichment of Moving Least Squares Finite Difference Method for Solving Elastic Crack Problems (탄성균열 해석을 위한 이동최소제곱 유한차분법의 내적확장)

  • Yoon, Young-Cheol;Lee, Sang-Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.5A
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    • pp.457-465
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    • 2009
  • This study presents a moving least squares (MLS) finite difference method for solving elastic crack problems with stress singularity at the crack tip. Near-tip functions are intrinsically employed in the MLS approximation to model near-tip field inducing singularity in stress field. employment of the functions does not lose the merit of the MLS Taylor polynomial approximation which approximates the derivatives of a function without actual differentiating process. In the formulation of crack problem, computational efficiency is considerably improved by taking the strong formulation instead of weak formulation involving time consuming numerical quadrature Difference equations are constructed on the nodes distributed in computational domain. Numerical experiments for crack problems show that the intrinsically enriched MLS finite difference method can sharply capture the singular behavior of near-tip stress and accurately evaluate stress intensity factors.

Characteristics of Junior Ranger Activity Books of U.S. National Parks and Their Implications for Geomorphological Education in Korea (미국 국립공원 주니어레인저 워크북 특성 및 국내 지형교육에의 시사점)

  • Kim, Taeho
    • Journal of The Geomorphological Association of Korea
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    • v.28 no.1
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    • pp.101-114
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    • 2021
  • Junior Ranger is a self-directed interpretation program for young visitors at national parks in the United States. The success of this program can be largely attributed to the role of an activity book which is given an applicant free of charge at a visitor center. This study aims to analyze the main characteristics of activity books for 14 national parks' Junior Ranger and to draw some implications for Korean geomorphological education. Although the activity books are varied in size, volume and printing, all of them offer diverse activities which are composed of different contents related to park resources in four fields and are performed in different ways such as Q&A, picture and word game, and creative activity. The time-consuming activities including attendance at a ranger-led program prevent the participant from making a superficial visit to be a junior ranger. The implications of the study are as follows: Firstly, the geomorphological education for children is needed to be strongly based on field experience learning and to be more carried out using a way of game rather than conventional Q&A, suggesting that it encourages students not to lose their interest for learning. Secondly, it is also necessary for the learning contents to be focused on various resources related to landform as well as landform itself. In addition, a creative activity such as writing verse or drawing feeling should be more applied to the geomorphological education in order to enhance their effects on affective domain beyond cognitive one. It is likely to be an alternative approach to understand landform by internalizing a sense of landform.

Development of User Based Recommender System using Social Network for u-Healthcare (사회 네트워크를 이용한 사용자 기반 유헬스케어 서비스 추천 시스템 개발)

  • Kim, Hyea-Kyeong;Choi, Il-Young;Ha, Ki-Mok;Kim, Jae-Kyeong
    • Journal of Intelligence and Information Systems
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    • v.16 no.3
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    • pp.181-199
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    • 2010
  • As rapid progress of population aging and strong interest in health, the demand for new healthcare service is increasing. Until now healthcare service has provided post treatment by face-to-face manner. But according to related researches, proactive treatment is resulted to be more effective for preventing diseases. Particularly, the existing healthcare services have limitations in preventing and managing metabolic syndrome such a lifestyle disease, because the cause of metabolic syndrome is related to life habit. As the advent of ubiquitous technology, patients with the metabolic syndrome can improve life habit such as poor eating habits and physical inactivity without the constraints of time and space through u-healthcare service. Therefore, lots of researches for u-healthcare service focus on providing the personalized healthcare service for preventing and managing metabolic syndrome. For example, Kim et al.(2010) have proposed a healthcare model for providing the customized calories and rates of nutrition factors by analyzing the user's preference in foods. Lee et al.(2010) have suggested the customized diet recommendation service considering the basic information, vital signs, family history of diseases and food preferences to prevent and manage coronary heart disease. And, Kim and Han(2004) have demonstrated that the web-based nutrition counseling has effects on food intake and lipids of patients with hyperlipidemia. However, the existing researches for u-healthcare service focus on providing the predefined one-way u-healthcare service. Thus, users have a tendency to easily lose interest in improving life habit. To solve such a problem of u-healthcare service, this research suggests a u-healthcare recommender system which is based on collaborative filtering principle and social network. This research follows the principle of collaborative filtering, but preserves local networks (consisting of small group of similar neighbors) for target users to recommend context aware healthcare services. Our research is consisted of the following five steps. In the first step, user profile is created using the usage history data for improvement in life habit. And then, a set of users known as neighbors is formed by the degree of similarity between the users, which is calculated by Pearson correlation coefficient. In the second step, the target user obtains service information from his/her neighbors. In the third step, recommendation list of top-N service is generated for the target user. Making the list, we use the multi-filtering based on user's psychological context information and body mass index (BMI) information for the detailed recommendation. In the fourth step, the personal information, which is the history of the usage service, is updated when the target user uses the recommended service. In the final step, a social network is reformed to continually provide qualified recommendation. For example, the neighbors may be excluded from the social network if the target user doesn't like the recommendation list received from them. That is, this step updates each user's neighbors locally, so maintains the updated local neighbors always to give context aware recommendation in real time. The characteristics of our research as follows. First, we develop the u-healthcare recommender system for improving life habit such as poor eating habits and physical inactivity. Second, the proposed recommender system uses autonomous collaboration, which enables users to prevent dropping and not to lose user's interest in improving life habit. Third, the reformation of the social network is automated to maintain the quality of recommendation. Finally, this research has implemented a mobile prototype system using JAVA and Microsoft Access2007 to recommend the prescribed foods and exercises for chronic disease prevention, which are provided by A university medical center. This research intends to prevent diseases such as chronic illnesses and to improve user's lifestyle through providing context aware and personalized food and exercise services with the help of similar users'experience and knowledge. We expect that the user of this system can improve their life habit with the help of handheld mobile smart phone, because it uses autonomous collaboration to arouse interest in healthcare.

A Method for Real Time Target Following of a Mobile Robot Using Heading and Distance Information (방향각 및 거리 정보에 의한 이동 로봇의 실시간 목표물 추종 방법)

  • Ko, Nak-Yong;Seo, Dong-Jin;Moon, Yong-Seon
    • Journal of the Korean Institute of Intelligent Systems
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    • v.18 no.5
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    • pp.624-631
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    • 2008
  • This paper presents a method for a mobile robot to follow a moving object in real time. The robot follows a target object keeping the facing angle toward the target and the distance to the target to given value. The method consists of two procedures: first, the detection of target position in the robot coordinate system, and the second, the calculation of translational velocity and rotational velocity to follow the object:. To detect the target location, range sensor data is represented in histogram. Based on the real time calculation of the location of the target relative to the robot, translational velocity and rotational velocity to follow the target are calculated. The velocities make the heading angle and the distance to target converge toward the desired ones. The performance of the method is tested through simulation. In the simulation, the target moves with three different trajectories, straight line trajectory, rectangular trajectory, and circular trajectory. As shown in the results, it is inevitable to lose track temporarily of the target when the target suddenly changes its motion direction. Nevertheless, the robot speeds up to catch up and finally succeeds to follow the target as soon as possible even in this case. The proposed method can also be utilized to coordinate the motion of multiple robots to keep their formation as well as to follow a target.

Reduction of Authentication Cost Based on Key Caching for Inter-MME Handover Support (MME 도메인간 핸드오버 지원을 위한 키캐싱 기반 인증비용의 감소기법)

  • Hwang, Hakseon;Jeong, Jongpil
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.13 no.5
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    • pp.209-220
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    • 2013
  • Handover is the technology to minimize data lose of mobile devices and make continuous communication possible even if the device could be moved from one digital cell site to another one. That is, it is a function that enables the mobile user to avoid the disconnection of phone conversations when moving from a specific mobile communication area to another. Today, there are a lot of ongoing researches for fast and efficient hand-over, in order to address phone call's delay and disconnection which are believed to be the mobile network's biggest problems, and these should essentially be resolved in all mobile networks. Thanks to recent technology development in mobile network, the LTE network has been commercialized today and it has finally opened a new era that makes it possible for mobile phones to process data at high speed. In LTE network environment, however, a new authentication key must be generated for the hand-over. In this case, there can be a problem that the authentication process conducted by the hand-over incurs its authentication cost and delay time. This essay suggests an efficient key caching hand-over method which simplifies the authentication process: when UE makes hand-over from oMME to nMME, the oMME keeps the authentication key for a period of time, and if it returns to the previous MME within the key's lifetime, the saved key can be re-used.

A Compensation Method of Timing Signals for Communications Networks Synchronization by using Loran Signals (Loran 신호 이용 통신망 동기를 위한 타이밍 신호 보상 방안)

  • Lee, Young-Kyu;Lee, Chang-Bok;Yang, Sung-Hoon;Lee, Jong-Gu;Kong, Hyun-Dong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.11A
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    • pp.882-890
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    • 2009
  • In this paper, we describe a compensation method that can be used for the situation where Loran receivers lose their phase lock to the received Loran signals when Loran signals are employed for the synchronization of national infrastructures such as telecommunication networks, electric power distribution and so on. In losing the phase lock to the received signals in a Loran receiver, the inner oscillator of the receiver starts free-running and the performance of the timing synchronization signals which are locked to the oscillator's phase is very severly degraded, so the timing accuracy under 1 us for a Primary Reference Clock (PRC) required in the International Telecommunications Union (ITU) G.811 standard can not be satisfied in the situation. Therefore, in this paper, we propose a method which can compensate the phase jump by using a compensation algorithm when a Loran receiver loses its phase lock and the performance evaluation of the proposed algorithm is achieved by the Maximum Time Interval Error (MTIE) of the measured data. From the performance evaluation results, it is observed that the requirement under 1 us for a PRC can be easily achieved by using the proposed algorithm showing about 0.6 us with under 30 minutes mean interval of smoothing with 1 hour period when the loss of phase lock occurs.

The Sexual Life In Climacteric Women (갱년기 여성의 성생활에 대한 조사)

  • Park, Sin-Ae;Kim, Myung-Ae
    • Women's Health Nursing
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    • v.5 no.2
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    • pp.204-221
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    • 1999
  • Due to the ever increasing life-span of human beings, the average woman is living well into her 70's. Henceforth, they spend at least one-third of their life after menopause. Climacteric encompasses the time preceding, during, and proceeding menopause : a transitional period of shifting from the period of being fertile to the period of senescence. In other words, this is the time at which they lose the ability to reproduce. Menopause can influence a woman's sexual life immensely due to the physiological, social, and psychological changes that occur during that period. In korea, where some women still live according to Confucian Culture in terms of sexology, nurses can play a vital role in the dissemination of sexual facts to women. This study was designed to clarity the characteristic and satisfaction of sexual life. This was done according to the classification of three types of climacteric women : pre-meno-pausal, menopausal, and post-menopausal. I studied 159 climacteric women between the ages of 45 & 59, living in or around the vicinity of Taegu City. This study utilized the investigative tools for sexual life patterns which were constructed with field experts' consultation and reference review by the author. The sexual satisfaction was translated from DSFI. The climacteric symptoms were invented by Kupperman, This research is descriptive. The data was collected between July 15, 1998 and October 14, 1998. Statistical analysis was performed using ANOVA and Pearson Correlations, and was computed with the SPSS program. The results obtained are summarized as follows; The frequency of sexual activity was highest in pre-menopause and declined after menopause. The frequency of genital caressing declined after menopause. The difference between the frequency of masturbation and coital pain was not significant according to the classification set forth in this experiment. Congruently, the frequency of orgasms declined after menopause. The mean satisfaction of sexual life is 27.1 years. The range of expected score is 9-45 years of age. Satisfaction was highest in the pre-menopausal group and proved to be statistically significant. Some of the general characteristics that affected the satisfaction a woman's sexual life in the climacteric stage during this project were ; age, income, satisfaction in younger pre-menopausal and the large income group than the other experimental groups. The climacteric symptoms were conversely correlated with the satisfaction in one's sexual life.

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A Survey on Weight Control Diets Practiced by College Women in Taegu and Kyung Buk (대구 , 경북지역 여자대학생의 체중조절 방법과 생활 태도에 관한 조사)

  • Park, Myeong-Hui;Choe, Yeong-Seon
    • Journal of the Korean Dietetic Association
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    • v.4 no.2
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    • pp.200-211
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    • 1998
  • Most of college women are interested in their appearances, and those whose body weights are normal or even underweight try to lose weight. Many methods for weight control diets practiced by college women are unsound and irrational so that some side-effects should be watched out. The present study was aimed to investigate methods of diets, food habits, behaviors, and side effects of weight control and to suggest sound weight loss schemes for college women. The subjects were 353 college women living in Taegu and Kyung Buk area, comprising 178 women who have tried weight control diets and 175 women who have not tried diets. The items included in questionnaires were food habits, food behavoirs, food frequency, physical activity status, 24-hour daily activity record, height, weight, etc., and the survey was conducted in September 1997. There was no difference in body mass index between college women who have tried diets(20.1$\pm$2.26) and women who have not tried diets(19.3$\pm$1.58), and 24.2% of those who have tried diets had body mass index under 19. The leading reason for diets was to make better fitting for costumes(67%). While women who have tried diets also tried to exercise more, they tended to overeat than women who have not tried diets. Mean of food habit scores(9.33 vs 9.32) which corresponded to "poor" habit and food frequencies were not different with or without experiences of diets. This indicated that diets were not related to actual changes of food habits and food intakes. Diet methods used frequently by college women were relying on special diet foods(25.4%), fasting(24.9%) and exercise(22.6%). Trying both exercise and diet was practiced by only 5.1% of the subjects who have tried diets. The duration time of diets was mostly in the range of 1 week to 1 month, and the longer diet period was, the more weight loss was. The frequent side effects due to diets were anemia(41.8%) and enervation(23.7%). Activity coefficients were lower in those who have tried diets(1.38$\pm$0.13) than those who have not tried diets(1.41$\pm$0.19). Women who have tried diets spent more time on reading newspapers and magazines and on watching TV. This study indicates that college women who have tried diets practiced irrational diets for weight reduction and experienced undesirable side-effects. Therefore scientific and systematic weight reduction programs accompanying balanced diets and proper exercise with behavior changes should be developed.

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A Study on the value and importance of Dancefilm: Focusing on the Wim Vandekeybus's Blush (댄스필름의 역사와 영상기법에 대한 연구 : 빔 반데키부스(Wim Vandekeybus)의 <블러쉬(Blush)>를 중심으로)

  • PARK, Youjung
    • Trans-
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    • v.1
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    • pp.45-66
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    • 2016
  • The study uses the image technique of the movie (analysis) since there are limited analyses and data of the dance film's (cinematic) grammar. The films are limited to the Wim Vandekeybus's Blush. From the analysis of the one film, films are directed using basic movie grammars. Although the films are of the same genre, it differs from the method of using image techniques as well as the director's personal art preference. The cinematic grammars enhance the effect of the movement and it emphasizes the objectives to deliver the audience true meaning of the films. Dance film is not a simple word combination of dance and film to record new type of art; dance is used for the movie's artistic and aesthetic enhancement. To find out dance is the language and important expressive tool of the dance film, at the same time cinematic grammar enhances effect of dance and objective of the film, the study uses image technique analysis. These are the results of dance film analysis by using image techniques. Firstly, Dance film can transcend time and space. Secondly, The creative director could emphasize some part that the audience should focus on to clearly deliver the intention of the choreographer. Lastly, To popularize the dance genre. If the dance film produces with more diversified stories than the resent, it will be a part of a cultural industry and could create profits. Dance film might lose the sense of realism, which is the main characteristic of the stage art; however it could feel the beauty of the film through the mise en scene.

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On-site Treatments and Conservation of Ox Bones Excavated from Bogam - ri tumulus, Naju (나주 복암리 고분군 출토 소뼈의 수습 및 보존처리)

  • Lee, Jung-Min;Park, Young-Hwan;Youn, Hye-seong;Ham, Chul-Hee;Kwon, Hyuk-nam
    • 보존과학연구
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    • s.36
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    • pp.74-85
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    • 2015
  • An ox bone object was excavated from the wetland at the excavation site in Bogam-ri tumulus, Naju. It was only able to identify the full image of the shape. Bogam were deteriorated and cracked due to the soil pressure and the repeated cycle of freezing and melting. They were also fragmented in pieces and powdered. In situ, bones were dewatered, consolidated and wrapped together with surrounding soils not to lose the fragmented bone pieces. Unpacking was carried out in the conservation lab and the treatment was processed. Soils on the reverse were removed and then the surface was consolidated and reinforced. Then, soils on the excavated side was cleaned and the surface was consolidated. The object was placed in the produced storing box. When the ox bone object was excavated, it did not have its head and was in the shape of tieing all its legs up. This shows that the animal had been tied up during a ritual and then buried. During the treatment, the importance of the burial purpose and maintaining the shape at the time of excavation was considered. Therefore, the shape of the object at the time of excavation was maintained rather than dismantling all these fragile bones and finding the shape of an ox. This conservation of ox bone object shows that conservation treatment methods have to be vary depending on characters and conditions of objects. In addition, it is expecting that this writing could be the reference to bone and horn objects excavated in the future for the whole process from the excavation to the conservation treatment.

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