• Bulletin of the Society of Naval Architects of Korea
• /
• v.14 no.1
• /
• pp.1-10
• /
• 1977

The major objects of this report are to supplement data of natural frequencies of thin elastic rectangular plates to the available data, and to give an experimental verification for natural frequencies obtained by Rayleigh-Ritz method, the generation set of which are eigenfunctions of Euler beams. For the first object the following five models, for which data only for the fundamental mode or data only for square plates are available, are adopted; (1) two opposed edges are clamped and the other two opposed edges simply supported (C-C, S-S), (2) one edge is simply supported and the other three edges clamped (C-C, C-S), (3) one edge is free and the other three edges clamped (C-C, C-F), (4) two adjacent edges are clamped and the other two adjacent edges free (C-F, C-F). For the (C-C, S-S) model the frequency equation obtained with the mode shapes assumed as of a single trigonometric series is solved. And for the other four models Rayleigh-Ritz method taking eigenfunctions of Euler beams as the generating set is applied. The numerical examples are obtained up to the fourth, the fifth or the sixth order depending on the range of the aspect ratio (0.1-10.0). The number of terms in the generating set for Rayleigh-Ritz method is fifteen for all models. For the experiment three models made of 3.2mm thickness mild steel plate for general structure use were prepared in following size; $300mm{\times}600mm,\;600mm{\times}600mm\;and\;900mm{\times}600mm$. Their boundary conditions are made to fit (C-C, C-F) condition. From the experiment mechanical impedance curves based on the frequency response method were obtained together with phase relation diagrams. The experimental data are resulted in good conformity to calculated values.

• Journal of the Architectural Institute of Korea Planning & Design
• /
• v.34 no.10
• /
• pp.33-44
• /
• 2018

The purpose of this research is to identify the characteristics of the positive and negative expressions about residential common life between the elderly and the young and present the direction on Homeshare. In-depth interviews were conducted from Feb. to May 2016 to identify the experiences of residential common life with 10 elderly and 11 young. The result is as follows. First, Homeshare dwelling was classified into five themes of human being, residential environment, life, management and emotion. Homeshare unlike ordinary dwelling centered on blood relatives, is characteristic to involve the management that connects between the elderly and young. Second, both the elderly and young were analyzed to be positive about the residential common life. It was shown that the elderly are most positive about human being, whereas young are positive about management and residential environment. The elderly is positive to mutual exchange with the young and young's independent life but the young is positive to factors that support comfortable personal life. Third, negative expression was shown a generation gap between the elderly and the young. The elderly recognized to be negative that young people has lived freely without consideration for the elderly. In order to solve these factors, it is necessary to make improvements through arranging rules for living. Fourth, three themes, human being, residential environment and life, analyzed to be the most important factors to sustain residential common life of Homeshare. The link between management and 3 themes leads to an expansion of positive emotion, which is structurally stable and is expected to increase the sustainability of the residential common life on Homeshare.

• Journal of the Korean housing association
• /
• v.25 no.1
• /
• pp.63-71
• /
• 2014

This research is aimed to analyze the basic characteristics of the 16 floor plans of 4 small-sized apartments in DaLian-City. Recently, there are increasing that a small-sized apartments for new younger generation in China. The younger ages intend to got a new floor plan types apartments according to own's life style. Also, a lot of construction company showed the many types of new residential space design during the last about 10 years, in DaLian City. The research results are summarized as follows: First, all of the floor plan types were '-' shape, 'L' shape. Second, there were several co-relational types of space plan between living room, kitchen and dining space. Those are LDK, L K, L DK, LD K. Third, the bedroom of the $30m^2$-floor plan size has an open-space design but over the size of $40m^2$-floor plan the space is closed design. Fourth, The number of bathrooms in all the floor plans is just 1 and it's placed beside the entrance except for B3, C4. The basic equipments of the lavatory was a toilet, a washbowl, a shower. A bathtub is installed in the floor plans greater than $60m^2$. Fifth, almost all of the characteristics of the spatial interrelation - each room position order - based on the location of the entrance. In particular, almost all of the bedrooms are furthest from the entrance for the most privacy.

• Journal of Korean Elementary Science Education
• /
• v.30 no.2
• /
• pp.189-203
• /
• 2011

The object of this study is to investigate the views of scientifically gifted children about the purpose of scientists' experiments and school science experiments. The children's views were examined using a open-ended questionnaire survey. And then the responses from the children were analyzed with categorization. The results from the study are as follows: First, the children's views about the purpose of scientists' experiments and school science experiments were classified to 2 top-level, 5 mid-level and 21 sub-level categories. Second, it was found that the children considered internal values of doing experiments are more worthy than the social and personal usefulness of the experiments. Third, the gifted children mentioned most frequently that the purposes of the scientist experiment is 'to get the evidences for their theory and argument which is unusual in the regular children's views. Also the discovery of new phenomena and materials, and the generation of new theories and ideas were mentioned as purposes of the scientist experiments. Fourth, the students frequently stated that school science experiments support effective learning of science subject enhancing subject interests and better explanation/understanding. Fifth, relatively many students thought that the purposes of school science experiments are different with those of scientist experiments. Based on the results from the study, some educational suggestions are discussed.

• Journal of Korea Water Resources Association
• /
• v.32 no.3
• /
• pp.291-300
• /
• 1999

The Snyder's synthetic unit hydrograph method is selected to apply the concept of the fractal dimension by stream order for the practicable rainfall-runoff generation, and fourth types of the Snyder's relation are derived from topographic and observed unit hydrograph data of twenty-nine basins. As a result of the analysis of twenty-nine basins and the verification of two basins, the Snyder's relation which considers the fractal dimension of the stream length and uses calculated unit hydrograph data shows the best result. The concept of the fractal dimension by stream order is applied to the Snyder's synthetic unit hydrograph method. The topographic factors, used in the Snyder's synthetic unit hydrograph method, which have a property of the stream length like $L_{ma}$ (mainstream length) and $L_{ca}$ (length along the mainstream to a point nearest the watershed centroid) were considered. In order to simplify the fractal property of stream length, it is supposed that $L_{ma}$ has not the fractal dimension and the stream length between $L_{ma}$ and ($L_{ma}\;-\;L_{ca}$) has the fractal dimension of 1.027. From the utilization of this supposition, a new Snyder's relation which consider the fractal dimension of the stream length occurred by the map scale used was finally suggested.

• Journal of the Institute of Convergence Signal Processing
• /
• v.6 no.2
• /
• pp.100-106
• /
• 2005

OFDM is one of the promising modulation candidates for a fourth generation broadband mobile communication system because of its robustness against inter-symbol inteference(ISI). The OFDM transmission technique has the inherent flexibility to adapt the modulation scheme on each subcarrier according to the signal-to-noise ratio(SNR). In this paper, the adaptive modulation scheme of OFDM system is proposed in broadband mobile channel. The proposed algorithm allocates initially the number of bits in each subcarrier using the threshold SNR according to the target BER and controls the total number of target bits using the well-known algorithm of Chow et al. In addition, the subcarriers of the proposed algorithm are clustered in blocks, that the signalling overhead can be reduced for the bit allocation of subcarriers. For the simulated experiments, this paper presents an evaluation for the effects of target BER, the various numbers of subcarriers in the subband block, and Doppler frequency on the performance of adaptive OFDM in broadband mobile channel.

• Journal of Korean Library and Information Science Society
• /
• v.36 no.4
• /
• pp.99-113
• /
• 2005

The purpose of this research is to analyze the operational state of Distance universities' electronic libraries through the Lifelong Education Law, and to find out the related problems. The main investigational focus was on the operational methodologies of the libraries and the usage levels of the full-text service. The data were collected through accessing the URLs of 17 Distance universities authorized till 2005. The result is that every university is operating their libraries either on their own $(17.7\%)$ or by using the links to the external libraries $(82.4\%)$. However, only $(35.3\%)$ of the surveyed universities provide the full-text service available on the Internet. Thus, in order to establish the fourth generation Distance university based on the Internet and Web, it is urgently needed to improve the construction and operation standards of electronic libraries in the Lifelong Education Law.

• Korea journal of population studies
• /
• v.5 no.1
• /
• pp.4-16
• /
• 1982

The Korean Population Control Program has been implementing under the jurisdiction of the Ministry of Health and Social Affairs through an existing network of health centers. This arrangement was successful in bringing population growth down to targeted level by the end of the Fourth Five Year Economic Planning, 1981. It is expected, however, that future goal will be harder to reach due to difficulty of reducing traditional family size norms further and to the projected increasing the number of eligible couples as the past Korean war baby boom generation enters the reproductive activity in the next few years. The recognition of the need for modification of population policy is increasing. The 1980 census shows that the total number of population reached approximately 38.5 million with 1.57 per cent of the growth rate. It was projected that the size of Korean Population will reach around 42 million and 51 million in 1986 and 2000 respectively. Furthermore, there is some argument as to whether decline in the birth rate in Korea is too slow to meet government target. Hence, a new development of population policy and greatly increased amount of effort will be needed in order to achieve Zero Population Growth Rate before the year 2050. The development of future national population policy and its related area are recommended as follow: 1. It is highly recommended that the population planning law governing both vital events of birth and death and population migration should be legislated. 2. The National Population Policy Council, Chaired by Deputy Prime Minister should be activated to implement and coordinate population program within ministries. 3. Responsible organization of population and family planning program should be established as a Bureau unit at central government level. 4. For the improvement of national vital registration, an existing system should be studied and developed.

• Computers and Concrete
• /
• v.31 no.5
• /
• pp.457-468
• /
• 2023

Buildings, bridges, and dams are examples of civil infrastructure that play an important role in public life. These structures are prone to structural variations over time as a result of external forces that might disrupt the operation of the structures, cause structural integrity issues, and raise safety concerns for the occupants. Therefore, monitoring the state of a structure, also known as structural health monitoring (SHM), is essential. Owing to the emergence of the fourth industrial revolution, next-generation sensors, such as wireless sensors, UAVs, and video cameras, have recently been utilized to improve the quality and efficiency of building forensics. This study presents a method that uses a target-based system to estimate the dynamic displacement and its corresponding dynamic properties of structures using UAV-based video. A laboratory experiment was performed to verify the tracking technique using a shaking table to excite an SDOF specimen and comparing the results between a laser distance sensor, accelerometer, and fixed camera. Then a field test was conducted to validate the proposed framework. One target marker is placed on the specimen, and another marker is attached to the ground, which serves as a stationary reference to account for the undesired UAV movement. The results from the UAV and stationary camera displayed a root mean square (RMS) error of 2.02% for the displacement, and after post-processing the displacement data using an OMA method, the identified natural frequency and damping ratio showed significant accuracy and similarities. The findings illustrate the capabilities and reliabilities of the methodology using UAV to evaluate the dynamic properties of structures.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2020.08a
• /
• pp.75-75
• /
• 2020

Potatoes were first introduced outside the Andes region four centuries ago, and have become an integral part of much of the world's food. Potatoes were first introduced into Europe in the 16th century and Korea in the early 19th century. Potatoes have a short growing season, high production per unit area, relatively strong environmental adaptability, and are cultivated in more than 130 countries around the world. It is the world's fourth-largest crop, following rice, wheat, bean and maize. In the nutritional aspects, potatoes contain abundant vitamins and minerals, as well as an assortment of phytochemicals such as carotenoids and natural phenols. Due to the high content of potato functional compounds, it has known that potatoes are effective in the prevention of various human diseases. In particular, the potato contains a large amount of polar compounds, including the saponin in the polar compounds, and the physiological activity of the saponins, such as immunity enhancement, antioxidant and anti-inflammatory is known. In this study, the antioxidative activity of polar compounds from five potatoes was examined by cell based anti-oxidation assay. The smallest amount of ROS(Reactive oxygen species) was generated when the compound was derived from 'Haryung' and 'hongyoung' and strong SOD(Superoxide dismutase) activity was observed in 'Sumi' and 'Jayoung'. The results of this study reveal the antioxidative effect of polar compounds extracted from various kind of potatoes, which will enable the acquisition of new bioactive candidates and the establishment of new profit generation models for farmers