• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.5
• /
• pp.147-153
• /
• 2018

Beacon enables one to measure distance indoors based on low-power Bluetooth low energy (BLE) technology, while GPS (Global Positioning System) only can be used outdoors. In measuring indoor distance using Beacon, RSSI (Received Signal Strength Indication) is considered as the one of the key factors, however, it is influenced by various environmental factors so that it causes the huge gap between the estimated distance and the real. In order to handle this issue, we propose the adaptive ANN (Artificial Neural Network) based approach to measuring the exact distance using Beacon. First, we has carried out the preprocessing of the RSSI signals by applying the extended Kalman filter and the signal stabilization filter into decreasing the noise. Then, we suggest the multi-layered ANNs, each of which layer is learned by specific training data sets. The results showed an average error of 0.67m, a precision of 0.78.

• Proceedings of the Korea Association of Crystal Growth Conference
• /
• 1996.06a
• /
• pp.508-508
• /
• 1996

;The growth of films have considerable interest in the field of superlattice structured multi-layer epitaxy led to realization of new devices concepts. Molecular beam epitaxy (MBE) with in situ observation by reflection high-energy electron diffraction (RHEED) is a key technology for controlled layered growth on the atomic scale in oxide crystal thin films. Also, the combination of radical oxygen source and MBE will certainly accelerate the progress of applications of oxides. In this study, the growth process of single crystal films using by MBE method is discussed taking the oxide materials of Bi-Sr-Ca-Cu family. Oxidation was provided by a flux density of activated oxygen (oxygen radicals) from an rf-excited discharge. Generation of oxygen radicals is obtained in a specially designed radical sources with different types (coil and electrode types). Molecular oxygen was introduced into a quartz tube through a variable leak valve with mass flowmeter. Corresponding to the oxygen flow rate, the pressure of the system ranged from $1{\;}{\times}{\;}10^{-6}{\;}Torr{\;}to{\;}5{\;}{\times}{\;}10^{-5}$ Torr. The base pressure was $1{\;}{\times}{\;}10^{-10}$ Torr. The growth of Bi-oxides was achieved by coevaporation of metal elements and oxygen. In this way a Bi-oxide multilayer structure was prepared on a basal-plane MgO or $SrTiO_3$ substrate. The grown films compiled using RHEED patterns during and after the growth. Futher, the exact observation of oxygen radicals with MBE is an important technology for a approach of growth conditions on stoichiometry and perfection on the atomic scale in oxide. The oxidization degree, which is determined and controlled by the number of activated oxygen when using radical sources of two types, are utilized by voltage locked loop (VLL) method. Coil type is suitable for oxygen radical source than electrode type. The relationship between the flux of oxygen radical and the rf power or oxygen partial pressure estimated. The flux of radicals increases as the rf power increases, and indicates to the frequency change having the the value of about $2{\times}10^{14}{\;}atoms{\;}{\cdots}{\;}cm^{-2}{\;}{\cdots}{\;}S^{-I}$ when the oxygen flow rate of 2.0 seem and rf power 150 W.150 W.

• Korean Journal of Health Education and Promotion
• /
• v.26 no.1
• /
• pp.63-80
• /
• 2009

Objectives: This study identified how personal characteristics, healthy behavior and social capital might influence on physical activity of adults. Methods: This study used data from the health survey of a city of Korea. We surveyed 1,000 adults sampled by stratified sampling methods from 67,889 households. Outcome variable was the stage of physical activity which was broken into 5 categories. Sociodemographic factors, healthy behavior, self-rated health status and social capital were used as control variables. Sociodemographic factors included age, sex, educational status, economic status measured by deprivation score, residential period within survey city. Social capital was measured by Integrated Questionnaire for the Measurement of Social Capital (SC-IQ). This study used chi-square test and ordered logistic regression models to examine the associations between independent variables and physical activity. Variables were added to the regression model in three groups using a hierarchical approach. Results: Physical activity was significantly more likely to become active if they have higher educational status, healthier behavior. Among the six dimensions of SC-IQ, only "groups and networks" that is structural dimensions of social capital and "trust and solidarity" that is cognitive dimensions of social capital were significantly related to physical activity of adults. We found that a person having higher density of membership and having larger size of networks showed the high possibility of active physical activity. A person having high solidarity was significantly associated with physical activity, but general trust was inversely related to physical activity. Output dimensions of social capital did not show significant relationship to physical activity. Conclusion: We found that social capital is useful concept to explain health behaviors like physical activity. However we must consider social, cultural and political context of the study to evaluate the effect of social capital to health status and health determinants and to capture the exact meaning of relationship between them. We suggest further researches to refine the concept of social capital and to explain the relationship of social capital to diverse health determinants.

• Journal of Ocean Engineering and Technology
• /
• v.20 no.6 s.73
• /
• pp.101-107
• /
• 2006

Recently, with the increase in requirements for marine development, a marine urbanism is being visualized, with more and more huge-scale structures at the scope of the ocean space utilization. In particular, a pontoon-type structure has attracted attention, since The Floating Structures Association of Japan proposed a new concept as the most suitable one of floating airports. The Very Lage Floating Structure (VLFS) is considered a flexible structure, for a quite large length-to-breadth ratio and its geometrical flexibility. The main objective of this study is to makean exact and convenient prediction about the hydro-elastic response on very large offshore structures in waves. The numerical approach for the hydro-elastic responses is based on the combination of the three dimensional source distribution method and the dynamic response analysis method, which assumed a dividing pontoon type structure, as many rigid bodies connected elastic beam elements. The established hydo-elastic theory was applied to the radiation forces caused by motions of a whole structure, formulated using the global coordinate system, which has the origin at the center of the structure. However, in this paper, we took radiation forces, occurred by individual motions of floating bodies, into consideration. The calculated results show good agreement with the experimental and calculated results by Yago.

• Women's Health Nursing
• /
• v.5 no.1
• /
• pp.65-79
• /
• 1999

The purpose of this study was to figure out a direction for midwifes' expanded roles for integrative woman's health care focused on health promotion & maintenance and primary prevention of women's health disorders including family health in the new millenium as a primary women's health practitioner. Data sources used for analysis were the book published from International Confederation of Midwives including role, code, situation and others from the international aspects : the empirical data from direct contact by participation in the ICM held in Manila, Philipine, May 22-26, 1999 : and documentation of Korean Midwives Association. Historical and current changing perspectives toward woman's health & nurse-midwifery and the reality women's health & nurse-midwifery and the reality of expand role that should be acquired toward the new millenium are discussed. In conclusion, Nurse-midwives are the very primary women's health care providers who can provide not only the exact needs of women who have health related problems, which are developed in the unique socio-cultural context women are belonged to, but also reproductive affairs including labor and delivery as it was midwive's traditional role, not just as practitioner, educator, counselor but conscious raiser for women's right. Futhermore, for this, thorough preparation through various kind of active and contemplated approach such as remodeling roles and education and continuing education system, training for high skilled & technical action, making laws and policy, and others is absolutely required.

• Spatial Information Research
• /
• v.16 no.3
• /
• pp.317-330
• /
• 2008

In this paper, the acquisition of digital imagery and the orthoimage generation were performed to set up working process. And another purpose of this thesis is to evaluate the accuracy of orthoimage by overlapping digital topographic map and digital cadastral map on it. The digital topographic map and digital cadastral map were superimposed on the orthoimage to check the accuracy as another approach of evaluation. The RMSE is ${\pm}0.364m$ in X direction and ${\pm}0.413m$ in Y direction with digital topographical maps(1/5,000). And the RMSE is ${\pm}1.283m$ in X direction and ${\pm}1.085m$ in Y direction with digital cadastral map. It is necessary for the application of a newly developed digital aerial camera to make an exact synchronization between GPS/IMU data and image data, use a technology for setting a standard image resolution and the number of ground control points.

• ETRI Journal
• /
• v.36 no.1
• /
• pp.134-140
• /
• 2014

Many reports have shown that the access pattern for geospatial tiles follows Zipf's law and that its parameter ${\alpha}$ represents the access characteristics. However, visits to geospatial tiles have temporal and spatial popularities, and the ${\alpha}$-value changes as they change. We construct a mathematical model to simulate the user's access behavior by studying the attributes of frequently visited tile objects to determine parameter estimation algorithms. Because the least squares (LS) method in common use cannot obtain an exact ${\alpha}$-value and does not provide a suitable fit to data for frequently visited tiles, we present a new approach, which uses a moment method of estimation to obtain the value of ${\alpha}$ when ${\alpha}$ is close to 1. When ${\alpha}$ is further away from 1, the method uses the associated cache hit ratio for tile access and uses an LS method based on a critical cache size to estimate the value of ${\alpha}$. The decrease in the estimation error is presented and discussed in the section on experiment results. This new method, which provides a more accurate estimate of ${\alpha}$ than earlier methods, promises more effective prediction of requests for frequently accessed tiles for better caching and load balancing.

• Journal of Agricultural Extension & Community Development
• /
• v.24 no.2
• /
• pp.143-154
• /
• 2017

Saemaul Undong (SM U) initiated in Korea in the 1970's is widely acknowledged as a successful model for rural community development, despite its limitations. This paper investigates the success factors of the SMU model and the lessons thereof for Sam Sang Model of Lao PDR, which appears ineffective over the years. Results show that land reforms, social ties among villages, strong institutional support and leadership and incentive system as well as "top-down" and "bottom-up" development approaches are among the factors that significantly contributed to the success of the SMU. However, rural development program would not be effective if residents are unwilling to participate. Therefore, to successfully achieve rural community development in Lao PDR, the government should through the Sam Sang model employ top-down and bottom-up approaches to enhance local participation and address the exact needs of the local people.

• Journal of Institute of Control, Robotics and Systems
• /
• v.19 no.6
• /
• pp.527-533
• /
• 2013

BCI (Brain-Computer Interface) is a system that transforms a subject's brain signal related to their intention into a control signal by classifying EEG (electroencephalograph) signals obtained during the imagination of movement of a subject's limbs. The BCI system allows us to control machines such as robot arms or wheelchairs only by imaging limbs. With the exact same experiment environment, activated brain regions of each subjects are totally different. In that case, a simple approach is to use as many channels as possible when measuring brain signals. However the problem is that using many channels also causes other problems. When applying a CSP (Common Spatial Pattern), which is an EEG extraction method, many channels cause an overfitting problem, and in addition there is difficulty using this technique for medical analysis. To overcome these problems, we suggest an optimal channel selection method using a BPSO (Binary Particle Swarm Optimization), BPSO with channel impact factor, and GA. This paper examined optimal selected channels among all channels using three optimization methods and compared the classification accuracy and the number of selected channels between BPSO, BPSO with channel impact factor, and GA by SVM (Support Vector Machine). The result showed that BPSO with channel impact factor selected 2 fewer channels and even improved accuracy by 10.17~11.34% compared with BPSO and GA.

• Smart Structures and Systems
• /
• v.18 no.5
• /
• pp.983-1004
• /
• 2016

Nowadays, there are two classes of methods for damage detection in structures consisting of static and dynamic. The dynamic methods are based on studying the changes in structure's dynamic characteristics. The theoretical basis of this method is that damage causes changes in dynamic characteristics of structures. The dynamic methods are divided into two categories: signal based and modal based. The modal based methods utilize the modal properties consisting of natural frequencies, modal damping and mode shapes. As the modal properties are sensitive to changes in the structure, these can be used for detecting the damages. In this study, using dynamic method and modal based approach (natural frequencies and mode shapes), the objective function is formulated. Then, detection of damages of truss structures is addressed by using Simplified Dolphin Echolocation algorithm and solving inverse optimization problem. Many scenarios are used to simulate the damages. To demonstrate the ability of the algorithm, different truss structures with several multiple elements scenarios are tested using a few runs. The influence of the two different levels of noise in the modal data for these scenarios is also considered. The last example of this article is investigated using a different mutation. This mutation obtains the exact answer with fewer loops and population by limited computational effort.