• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.29 no.1
• /
• pp.84-91
• /
• 1996

Heat flux of the East China Sea was estimated with the bulk method, the East China mount based on the marine meteorological data and cloud amount data observed by a satellite. Solar radiation is maximum in May and minimum in December. Its amount decreases gradually southward during the winter half year (from October to March), and increases northward during the summer half year (from April to September) due to the influence of Changma (Baiu) front. The spatial difference of long-wave radiation is relatively small, but its temporal difference is quite large, i.e., the value in February is about two times greater than that in July. The spatial patterns of sensible and latent heat fluxes reflect well the effect of current distribution in this region. The heat loss from the ocean surface is more than $830Wm^{-2}$ in winter, which is five times greater than the net radiation amount during the same period, The annual net heat flux is negative, which means heat loss from the sea surface, in the whole region over the East China Sea. The region with the largest loss of more than $400Wm^{-2}$ in January is observed over the southwestern Kyushu. The annual mean value of solar radiation, long-wave radiation, sensible and latent heat fluxes are estimated $187Wm^{-2},\;-52Wm^{-2},\;-30Wm^{-2}\;and\;-137Wm^{-2}$, respectively, consequently the East China Sea losses the energy of $32Wm^{-2}(2.48\times10^{13}W)$. Through the heat exchange between the air and the sea, the heat energy of $0.4\times10^{13}W$ is supplied from the air to the sea in A region (the Yellow Sea), $2.1\times10^{13}W$ in B region (the East China Sea) and $1.7\times10^{13}W$ in C region (the Kuroshio part), respectively.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.12 no.1
• /
• pp.11-22
• /
• 2010

According to IPCC 4th Assessment Report, concentration of carbon dioxide has been increasing by 30% since Industrial Revolution. Most of IPCC $CO_2$ emission scenarios estimate that the concentration will reach up to double of its present level within 100-year if the current tendency continues. The global warming has resulted in the agro-climate change over the Korean Peninsula as well. Accordingly, it is necessary to understand the future agro-climate induced by the increase of greenhouse gases in terms of the agro-climatic indices in the Korean peninsula. In this study, the future climate is simulated by an atmosphere/ocean/land surface/sea ice coupled general circulation climate model, Pusan National University Coupled General Circulation Model(hereafter, PNU CGCM), and by a regional weather prediction model, Weather Research and Forecasting Model(hereafter, WRF) for the purpose of a dynamical downscaling. The changes of the vegetable period and the crop growth period, defined as the total number of days of a year exceeding daily mean temperature of 5 and 10, respectively, have been analyzed. Our results estimate that the beginning date of vegetable and crop growth periods get earlier by 3.7 and 17 days, respectively, in spring under the $CO_2$-doubled climate. In most of the Korean peninsula, the predicted frost days in spring decrease by 10 days. Climatic production index (CPI), which closely represent the productivity of rice, tends to increase in the double $CO_2$ climate. Thus, it is suggested that the future $CO_2$ doubled climate might be favorable for crops due to the decrease of frost days in spring, and increased temperature and insolation during the heading date as we expect from the increased CPI.

• Journal of Korea Society of Industrial Information Systems
• /
• v.23 no.5
• /
• pp.119-134
• /
• 2018

Today, many firms face the environment of high uncertainty and severe competition due to the rapid technology development and the diverse needs of customers. In the business environment, one of the most important ways to gain sustainable competitive advantage and future growth engine is related to NPD (New Product Development), which is a very important issue for practice and academia. Thus, this study intends to provide new values to practitioners and researchers related to NPD by analyzing current research trends and future trends in NPD field. For this, we bibliometrically analyzed keyword networks which consist of keywords that were already published in the eminent journals from Scopus database to generate insights that have not been captured in the previous reviews on the topic. As a result, we could understand the extant research streams in NPD field, and suggest the changes of specific research topics based on the connected relationships among keywords over the time. In addition, we also foresaw the general future research trends in NPD field based on the keywords according to preferential attachment processes. Through this study, it was confirmed that NPD keyword network is a small world network that follows the distribution of power law and the growth of network is formed by link formation by keyword preferential attachment. In addition, through component analysis and centrality analysis, keywords such as Innovation, New product innovation, Risk management, Concurrent engineering, Research and development, and Product life cycle management are highly centralized in NPD keyword network. On the other hand, as a result of examining the change of preferential attachment of keywords over the time, we suggested the required new research direction including i) NPD collaboration with suppliers, ii) NPD considering market uncertainty, iii) NPD considering convergence with the other academic areas like technology management and knowledge management, iv) NPD from SME(Small and medium enterprises) perspective. The results of this study can be used to determine the research trends of NPD and the new research themes for interdisciplinary studies with other disciplines.

• Journal of dental hygiene science
• /
• v.7 no.3
• /
• pp.113-119
• /
• 2007

This study attempts to find factors contributing to the use pattern of prosthetics by investigating the current condition of prosthetics for the aged of over 65 years old by place of practice. Among those of over 65 years old who live in Gangnam-gu, Seocho-gu, Seongbuk-gu, and Gwanak-gu of Seoul and use the apartment senior's center, those having prosthetics were selected as subjects of this study, and this study was conducted in forms of interview and record. Findings of this study are summarized as follows: First, in regard of the state of prosthetics and relevant symptoms in the mouth according to the place of prosthetics practice, there was significant difference in the questions except the medical benefit of prosthetics between unlicensed facilities and dental clinics and hospitals. Second, regarding difference in satisfaction according to the place of prosthetics practice, dental clinics and hospitals showed a higher level of aesthetic satisfaction than unlicensed facilities. For difference in satisfaction at pronunciation, chewing, pain, a sense of foreign body, and holding power, dental clinics and hospitals showed a higher level than unlicensed facilities, Third, after factor analysis on the perception factors of unlicensed treatment and dental treatment, unlicensed facilities showed the highest level of reliability, and then convenience, word of mouth, and modernity in order. Dental clinics and hospitals also showed the highest level of reliability, however, and then convenience, modernity, and word of mouth in order. Fourth, as a consequence of analyzing the factors to influence the use pattern of prosthetics, regarding residential pattern, there were higher possibilities to use dental clinics and hospitals when the subjects lived together with their children and in Gangnam, and the more were the number of pyeong for the residence, pocket money, medical expense, and property in their name, compared to unlicensed facilities. In conclusion, economic factors appear to be the most important factors in selecting facilities for denture prosthodontics. Therefore, it is important to ensure the denture prosthodontics for the elderly are reimbursable so that they can enjoy a healthier life.

• Journal of Korean Society of Forest Science
• /
• v.109 no.3
• /
• pp.259-270
• /
• 2020

Extreme weather events, such as heat and drought, have occurred frequently over the past two decades. This has led to continuous reports of cases of forest damage due to physiological stress, not pest damage. In 2014, pine trees were collectively damaged in the forest genetic resources reserve of Sogwang-ri, Uljin, South Korea. An investigation was launched to determine the causes of the dieback, so that a forest management plan could be prepared to deal with the current dieback, and to prevent future damage. This study aimedto 1) understand the topographic and structural characteristics of the area which experienced pine tree dieback, 2) identify the main causes of the dieback, and 3) predict future risk areas through the use of machine-learning techniques. A model for identifying risk areas was developed using 14 explanatory variables, including location, elevation, slope, and age class. When three machine-learning techniques-Decision Tree, Random Forest (RF), and Support Vector Machine (SVM) were applied to the model, RF and SVM showed higher predictability scores, with accuracies over 93%. Our analysis of the variable set showed that the topographical areas most vulnerable to pine dieback were those with high altitudes, high daily solar radiation, and limited water availability. We also found that, when it came to forest stand characteristics, pine trees with high vertical stand densities (5-15 m high) and higher age classes experienced a higher risk of dieback. The RF and SVM models predicted that 9.5% or 115 ha of the Geumgang Pine Forest are at high risk for pine dieback. Our study suggests the need for further investigation into the vulnerable areas of the Geumgang Pine Forest, and also for climate change adaptive forest management steps to protect those areas which remain undamaged.

• Journal of Environmental Health Sciences
• /
• v.10 no.2
• /
• pp.9-40
• /
• 1984

This thesis purports to overview the diverse administrative and organizational factors and plannings developed by the government organizations, municipal or otherwise, to tackle the Han River water pollution issues in the past years. This thesis also looks into the ever-worsening Han River water pollution problems, in particular, in terms of the various government plans ostensibly designed to reduce the pollution level but with little success. Also dealt with are the efficiencies with which the laws and decrees on water pollution the administrative organizations put to use in the prosecution of the diverse antiwater pollution projects involving the Han River basin. From the early 1960's up to the 1970's the government had concentrated on the growth-oriented economic policy with the result that little attention had been paid to the water pollution and other environmental issues that are bound to arise from the massive economic growth. Belatedly, the five-year Hah River Development Project was initiated in 1982 with emphasis on reducing the water pollution level at Hah River to the minimum. The following are the gists of the thesis and recommendations for the future antiwater pollution plans by the administrative organizations: 1. Documents to date indicate that the irrigation projects along the Han River area had been the main focus of attention during the Yi Dynasty and under the Japanese rule of the country. 2. Despite that the water pollution issue became the subject of many debates among the academic and research institutions in the 1960's and in the 1970's, the administrative organizations in charge of the Han River water quality control failed to come up with a concrete plan for the river's water quality control. 3. Nevertheless, the water pollution of the Han River area in fact began in the 1950's, with the unprecedented concentration into Seoul of population and the industrial facilities on a larger scale, in particular, enforced by the government's strong growthoriented policy in its Economic Development plans in the 1960's. 4. Starting in the 1960's, the Han River water pollution level dramatically increased, but the government was reluctant to promulgate or put into effect strong measures to curb the many factors contributing to the river water pollution, thus worsening the environmental issues along the Han River basin. 5. The environmental protection law and other laws and decrees relating to the antiwater and air pollution issues that were subsequently put into effect underwent so many changes that efficient anti-water pollution policies could not be effected for the Han River basin. The frequent organizational reshuffle within the administrative units concerned with environmental problems has resulted in the undue waste in personnel management and finance. 6. The administration on the environmental protection could not be efficiently carried out due to the organizational overlapping. Under the existing law, frequent organizational frictions and inefficiency are bound to occur among the central government offices themselves, as well as between the central government and the Seoul city administration, and among the city's administrative offices over the conservation of the Han River basin and over the river's anti-water pollution issue. 7. In the planning and prosecution of the Han River project, political influences from the president down to the lower-level politicious appear to have been involved. These political influences in the past had certainly had negative influence on the project, nevertheless, it appears that in the recent years, these political influences are not all that negative in view of the fact that they serve as a positive contributing factor in developing a better water quality control project along the Han River basin. The following are a few recommendations based on the data from the thesis: First, officials in charge of the Han River water quality control should pay attention to a careful screening of the opinions and recommendations from the academic circles and from the public should be made so that the government could better grasp the core issues in the environmental problems that require preventive and other necessary measures. Second, vigorous redistribution policies of population and industrial facilities away from the Seoul area should be pursued. Third, the government should refrain from revising or revamping too frequently the laws and decrees on the anti-water pollution, which is feared to cause undue inconveniences in the environmental administration. Fourth, a large-scale streamlining should be made to the existing administrative organization in an effort to do away with the inter- and intra-organizational friction. It is recommended that a secretariat for the Hah River basis conservation be established. Fifth, High-level administrative officials, with a thorough knowledge and vision on the Han River water quality control, should be prepared to better deal with the budgeting and personnel management for the Han River water pollution control not only at the control government, but also at the Seoul city municipal government levels. Environmental issues should be kept distinct from political issues. Environmental issues should not serve as a window-dressing for sheer political purposes. Sixth, the Hah River proiect should also include, along with the main Han River basin, those areas covering North Han River, South Han River, and the tributaries to the main river basin. The 'Han River Basin Water Quality Control Board' should be established immediately as a means of strengthening the current Han River basin water quality control policy. Seventh, in drawing up the Han River proiect, the administrative officials should be aware that Han River basin is a life line for those people in the region, providing them with not only a sheer physical space, but with a psychological living space for their everyday life.

• Korean Journal of Remote Sensing
• /
• v.31 no.6
• /
• pp.531-548
• /
• 2015

Atmospheric Motion Vector (AMV) from satellite images have shown Slow Speed Bias (SSB) in comparison with rawinsonde. The causes of SSB are originated from tracking, selection, and height assignment error, which is known to be the leading error. However, recent works have shown that height assignment error cannot be fully explained the cause of SSB. This paper attempts a new approach to examine the possibility of SSB reduction of COMS AMV by using a new target tracking algorithm. Tracking error can be caused by averaging of various wind patterns within a target and changing of cloud shape in searching process over time. To overcome this problem, Gaussian Mixture Model (GMM) has been adopted to extract the coldest cluster as target since the shape of such target is less subject to transformation. Then, an image filtering scheme is applied to weigh more on the selected coldest pixels than the other, which makes it easy to track the target. When AMV derived from our algorithm with sum of squared distance method and current COMS are compared with rawindsonde, our products show noticeable improvement over COMS products in mean wind speed by an increase of $2.7ms^{-1}$ and SSB reduction by 29%. However, the statistics regarding the bias show negative impact for mid/low level with our algorithm, and the number of vectors are reduced by 40% relative to COMS. Therefore, further study is required to improve accuracy for mid/low level winds and increase the number of AMV vectors.

• Journal of Korean Ophthalmic Optics Society
• /
• v.13 no.3
• /
• pp.65-71
• /
• 2008

Purpose: This paper studied the effect of eyes on the comparison between the distance optical centers problem of dispensing reading glasses made by optician and finished reading glasses in the current market. Methods: The method of this study has been measured by eleven different categories from +1.00D to +4.00D. This study also separated into three groups by their optical frame size and measured optical center point (O.C) and optical center height (O.H) with 200 peoples of man and females over 40 years old without ocular disease living in Gwang-san gu, Gwang-Ju city. Results: As a result, optical center point ranged from 57 mm to 80 mm and it turned to be most common range is from 61 mm to 65 mm (64.6%). Moreover, the optical center height ranged from 1 mm to 8mm and most common ranged (23%) were 4 mm. In other words, finished reading glasses have irregular optical ranges. After observing 200 people who are over 40 years old men and women, result shows that more than 75.5% (151 people) currently use finished reading glasses. Survey of 151 people, most common error between the finished reading glasses's O.C and the wearers P.D were 4 mm (45%). Furthermore, the most common error between the finished reading glassses's O.H and the wearers O.H ranged from 3 mm to 4 mm. Astonishingly, the entire 151 people who wear finished reading glasses appeal that they feel tiredness on their eyes when they wear finished reading glasses. 53 people (35%) claimed that they feel tiredness on their eyes after 10 to 20 minutes wearing finished reading glasses. Base on the research, We conducted more experiment to find the value of prism of optical centers err because it will tell us whether the finished reading glasses are good enough to wear or not. We multiplied diopter by the difference between finished reading glasses's O.C. and wearer's P.D. Consequently, We found out that the finished reading glasses counter to the German RAL-RG 915 policy. And We also found that it is relative to the diopter of lenses. In conclusion, based on the researched that wearing finished reading glasses have a dangerous factor for our vision. Therefore optician must need to recommend correctly made dispensing reading glasses based on the optical center point.

• Current Research on Agriculture and Life Sciences
• /
• v.14
• /
• pp.49-60
• /
• 1996

In order to evaluate soil factors affecting the growth of Italian poplar, 23 areas planted with Italian poplar were surveyed. These 23 areas were classified into 3 categories, river-side, fallow-land and hill-side. The growth performance and soil factors for each area were investigated. The growth of Italian poplar at river-side was shown to be superior to that of fallow-land and fill-side. The rates of growth for fallow-land and hill-side are decreased by 8% and 21% compared to those of river-side, respectively. This suggests that plantation of Italian poplar at hill-side would not be profitable. Soil conditions of high productive area appeared liquid phase 20%, porosity 45%, water holding capacity 35 - 40%, soil hardness $1kg/cm^3$. pH 6 and rich in organic matter and total nitrogen. The results of factor analysis for soil factors affecting to Italian poplar growth that showed eigenvalue over 1 and communality value over 70% explained factor 1 : liquid phase, porosity and water holding capacity, factor 2 : pH and calcium, and factor 3 : soil hardness. This suggests that physical characteristics of soil is more important than chemical characteristics for Italian poplar growth. Multiregerssion analysis was conducted between diameter growth and soil hardness, liquid phase and calcium. The t-values for each independent variables showed significance at 1 - 10% level, but water holding capacity and pH are not significant. It is supposed that sites suitable to Italian poplar were alluvial plain of sandy loam or part of banking soil, well-ventilating soil, lower soil hardness, apposite soil moisture absorbing with about 100cm of ground water level, plentiful organic matters and total nitrogen and little acidity soil.

• Current Research on Agriculture and Life Sciences
• /
• v.4
• /
• pp.1-6
• /
• 1986

This study was conducted to find out the effect of $SiO_2$ treatment on the $SiO_2$ concentration in guttation liquid, the amount of guttation liquid exudated from the margin of rice leaves, and the relationships between $SiO_2$ concentration in guttation liquid and foliar burn during the rice seedling stage, using two rice varieties;Nagdong-byeo (a Japonica) and Samgang-byeo (a - Indica - Japonica hybrid). Seedlings were cultivated in water solution and enveloped in polyvinyl case ($50cm{\times}150cm{\times}70cm$). $SiO_2$ treatment increased the amount of guttation liquid, the amount of guttation liquid (Nagdong-byeo:4.30mg/plant, Samgang-byeo:4.34mg/plant)) treated with 200ppm of $SiO_2$ was greater than any other level, decreased over 200ppm of $SiO_2$. $SiO_2$ concentration in guttation liquid was increased as application rates of $SiO_2$ increased, showing the positive correlation, and $SiO_2$ in guttation liquid/$SiO_2$ in culture ratio decreased over 100ppm of $SiO_2$. The highest concenitration of $SiO_2$ (Nagdong-byeo:172.6ppm/lcc, Samgang-byeo:199.8ppm/lcc) in guttation liquid was obtained at 12 hrs after $SiO_2$ applied. Foliar burn seemed to be closely related with $SiO_2$ concentration in guttation liquid.