• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.3
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• pp.183-192
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• 1982

The variability of rice productivity during last 2 decades (1961-1980) of ten years before and after the introduction of"Tongil" was reviewed from the epochal, regional and varietal points of view. During that period the cultivated area of paddy rice have remained almost unchanged, while the total rice production have got elevated from 3, 463 million metric tons in 1961 to 6.006 million metric tons in 1977, recording 73.4% increase. This remarkable increase in rice production is considered to be attributable much to the development and release of new high yielding variety, "Tongil", coupled with the amelioration of cultural techniques. However, in 1978 Tongil type varieties experienced the epidemic outbreak of blast disease due to the shifted race population of blast fungus and in 1980 recorded poor rice production as low as in 1960's due to the unfavorable weather stress throughout the rice growing season, giving rise to many problems awaiting solutions for securing the stabilized high production of rice. The rice yield has continued the gradual increase during last two decades but its difference between farmer and research organization have got wider from 79kg/10a during 1960 to 1971 to 101kg/l0a during 1972 to 1980, and also the inter-regional differences have been increased from 50-60kg/10a to 80kg/10a during those periods. Therefore, this proves that we have raised the upper boundary of rice yield by increasing the yield potential of rice variety but have not changed those absolute deviations. Estimates indicate that the increased rice production during that period was indebted 40 percent to the varietal improvement and 13 percent to the ameliorated agro-technologies, and the rest, 47 percent, could be ascribed to the other factors besides varieties and cultural technologies such as the improved agricultural environments, etc. Of course, even though it cannot be expected to unify the cultural environments and the cultural technologies, provided that much efforts are to be endeavored to minimize the yield difference of 20 percent between farmer and research organizations and the inter-regional yield difference of 20 percent, much increased rice production can be expected to be achieved with the current level of cultural technology and the yielding potential of the present rice varieties. In order to expedite the above effects on rice production the followings are to be put into practices consitently and steadfastly. 1. Reinforcement of breeding for varieties with high yielding potential and less susceptible to climatic-stress and pests, and of basic physicoecological studies of rice plant for improving the cultural technologies. 2. Continuous endeavor to secure the stabilized cultural environments by improving the soil fertility and increasing the drainage and irrigation facilities. 3. Political back-up to encourage the farmers' incentives for production 4. Precise surveys for agricultural statistics to facilitate the long-term planninge long-term planning.

• Journal of Technology Innovation
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• v.17 no.2
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• pp.55-80
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• 2009

Technology innovation activity plays a pivotal role in constructing the entrance barrier for other firms and making process improvement and new product. and these activities give a profit increase and growth to firms. Thus, technology innovation activity can reduce the default risk of firms. However, technology innovation activity can also increase the firm's default risk because technology innovation activity requires too much investment of the firm's resources and has the uncertainty on success. The purpose of this study is to examine the effect of technology innovation activity on the default risk of firms. This study's sample consists of manufacturing firms listed on the Korea Securities Market and The Kosdaq Market from January 1,2000 to December 31, 2008. This study makes use of R&D intensity as an proxy variable of technology innovation activity. The default probability which proxies the default risk of firms is measured by the Merton's(l974) debt pricing model. The main empirical results are as follows. First, from the empirical results, it is found that technology innovation activity has a negative and significant effect on the default risk of firms independent of the Korea Securities Market and Kosdaq Market. In other words, technology innovation activity reduces the default risk of firms. Second, technology innovation activity reduces the default risk of firms independent of firm size, firm age, and credit score. Third, the results of robust analysis also show that technology innovation activity is the important factor which decreases the default risk of firms. These results imply that a manager must show continuous interest and investment in technology innovation activity of one's firm. And a policymaker also need design an economic policy to promote the technology innovation activity of firms.

• The Korean Journal of Nuclear Medicine Technology
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• v.21 no.1
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• pp.76-82
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• 2017

Purpose Whole body bone scan is one of the most frequently performed in nuclear medicine. Basically, both the anterior and posterior views are acquired simultaneously. Occasionally, it is difficult to distinguish the lesion by only the anterior view and the posterior view. In this case, accurate location of the lesion through SPECT / CT or additional static scan images are important. Therefore, in this study, various improvement activities have been carried out in order to enhance the work capacity of technologists. In this study, we investigate the effect of technologist training and standardized work process processes on bone scan error reduction. Materials and Methods Several systems have been introduced in sequence for the application of new processes. The first is the implementation of education and testing with physicians, the second is the classification of patients who are expected to undergo further scanning, introducing a pre-filtration system that allows technologists to check in advance, and finally, The communication system called NMQA is applied. From January, 2014 to December, 2016, we examined the whole body bone scan patients who visited the Department of Nuclear Medicine, Asan Medical Center, Seoul, Korea Results We investigated errors based on the Bone Scan NMQA sent from January 2014 to December 2016. The number of tests in which NMQA was transmitted over the entire bone scan during the survey period was calculated as a percentage. The annual output is 141 cases in 2014, 88 cases in 2015, and 86 cases in 2016. The rate of NMQA has decreased to 0.88% in 2014, 0.53% in 2015 and 0.45% in 2016. Conclusion The incidence of NMQA has decreased since 2014 when the new process was applied. However, we believe that it will be necessary to accumulate data continuously in the future because of insufficient data until statistically confirming its usefulness. This study confirmed the necessity of standardized work and education to improve the quality of Bone Scan image, and it is thought that update is needed for continuous research and interest in the future.

• Korean Journal of Ecology and Environment
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• v.37 no.3 s.108
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• pp.344-354
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• 2004

A pilot study was performed from September 2000 to April 2004 to examine the feasibility of the wetland-pond system for the agricultural reuse of reclaimed water. The wetland system was a subsurface flow type, with a hydraulic residence time of 3.5 days, and the subsequent pond was 8 $m^3$ in volume (2 m ${\times}$ 2 m ${\times}$ 2 m) and operated with intermittent-discharge and continuous flow types. The wetland system was effective in treating the sewage; median removal efficiencies of $BOD_5$ and TSS were above 70.0%, with mean effluent concentrations of 27.1 and 16.8 mg $L^{-1}$, respectively, for these constituents. However, they did often exceed the effluent water quality standards of 20 mg $L^{-1}$. Removal of T-N and T-P was relatively less effective and mean effluent concentrations were approximately 103.2 and 7.2 mg $L^{-1}$, respectively. The wetland system demonstrated high removal rate (92 ${\sim}$ 90%) of microorganisms, but effluent concentrations were in the range of 300 ${\sim}$ 16,000 MPN 100 $mL^{-1}$ which is still high for agricultural reuse. The subsequent pond system provided further treatment of the wetland effluent, and especially additional microorganisms removal in addition to wetland-pond system could reduce the mean concentration to 1,000 MPN 100 $mL^{-1}$ from about $10^5$ MPN 100 $mL^{-1}$ of wetland influent. Other parameters in the pond system showed seasonal variation, and the upper layer of the pond water column became remarkably clear immediately after ice melt. Overall, the wetland system was found to be adequate for treating sewage with stable removal efficiency, and the subsequent pond was effective for further polishing. This study concerned agricultural reuse of reclaimed water using natural systems. Considering stable performance and effective removal of bacterial indicators as well as other water quality parameters, low maintenance, and cost-effectiveness, wetland- pond system was thought to be an effective and feasible alternative for agricultural reuse of reclaimed water in rural area.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.172-181
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• 2015

This study intends to improve the radiation safety management and the recognition for handling radiation using structured questionnaires to dental hygienists working at Jeollabuk-do from September 1 to October 31 in 2014. As a result, 63% of respondents have not received education for radiation safety management. Moreover, the practical degree for radiation safety management was $2.58{\pm}1.11$, while the degree of knowledge was $3.74{\pm}0.83$ of total 5.0. The results of insecurity for radiation danger were high as $3.88{\pm}0.92$, and insecurity for fetus during pregnancy shows the highest value as $4.43{\pm}0.71$. From the results of statistical significance level, the knowledge degree of radiation safety management is affected by total numbers of radiograpy for a day (p<0.05), and the practical degree of radiation safety management is affected by age group, academic background, monthly income, continuous service year, practice area, present position, and status of radiography in present (p<0.05). In addition, the knowledge degree of radiation safety management have a negative correlation (r=-0.232) with the practical degree, but have a positive correlation (r=0.262) with the insecurity for radiation danger. The high knowledge degree of radiation safety management (${\beta}=0.252$, p<0.001) and the short radiography work period (${\beta}=-0.341$, p<0.05) were the influential factors to the insecurity for radiation danger. Consequently, countermeasures are necessary to encourage dental hygienists to put their radiation safety management knowledge into the practice and to reduce the insecurity degree for radiation danger. Furthermore, it is important to prevent psychological and physical risks by radiation exposure through the improvement of radiation safety management level and recognition for handling radiation to improve medical environment.

• Laboratory Medicine and Quality Assurance
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• v.40 no.2
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• pp.51-69
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• 2018

As part of the immunoserology program of the Korean Association of External Quality Assessment Service, we organized two trials on the external quality assessment of hepatitis viral markers in 2016 and 2017. The hepatitis viral antigens and antibodies program consisted of 10 test items. We delivered two and three types of pooled sera specimens to 965 and 965 institutions for the first and second trials of external proficiency testing in 2016, respectively. The number of participating laboratories was 915 (94.8%) and 913 (95.0%) in the first and second trials in 2016, respectively. We also delivered three kinds of pooled sera specimens to 936 and 1,015 institutions for the first and second trials of external proficiency testing in 2017, respectively. The number of participating laboratories was 920 (98.3%) and 996 (98.1%) in the first and second trials in 2017, respectively. The most commonly tested items were hepatitis B surface antigen, followed by the antibodies to hepatitis B surface antigen, anti-hepatitis C virus, hepatitis B envelope antigen, antibodies to hepatitis B envelope antigen, anti-hepatitis A virus and antibodies to hepatitis B core antigen. The most frequently used methods for detecting viral markers were the chemiluminescence immunoassay and the electrochemiluminescence immunoassay, but they yielded a few-false positive results due to the matrix effect. The immunochromatographic assay yielded false-negative results for anti-hepatitis A virus due to low sensitivity. Continuous improvement in the quality of viral hepatitis testing through participation in the survey seems necessary.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.6
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• pp.256-268
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• 2016

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2015. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering were carried out in the areas of flow, heat and mass transfer, cooling and heating, and air-conditioning, the renewable energy system and the flow inside building rooms. Research issues dealing with air-conditioning machines and fire and exhausting smoke were reduced. CFD seems to be spreading to more research areas. (2) Research works on heat transfer area were carried out in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the economic analysis of GHG emission, micro channel heat exchanger, effect of rib angle on thermal performance, the airside performance of fin-and-tube heat exchangers, theoretical analysis of a rotary heat exchanger, heat exchanger in a cryogenic environment, the performance of a cross-flow-type, indirect evaporative cooler made of paper/plastic film. In the area of pool boiling and condensing, the bubble jet loop heat pipe was studied. In the area of industrial heat exchangers, researches were performed on fin-tube heat exchanger, KSTAR PFC and vacuum vessel at baking phase, the performance of small-sized dehumidification rotor, design of gas-injection port of an asymmetric scroll compressor, effect of slot discharge-angle change on exhaust efficiency of range hood system with air curtain. (3) In the field of refrigeration, various studies were carried in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, a cold-climate heat pump system, $CO_2$ cascade systems, ejector cycles and a PCM-based continuous heating system were investigated. In the alternative refrigeration/energy system category, a polymer adsorption heat pump, an alcohol absorption heat pump and a desiccant-based hybrid refrigeration system were investigated. In the system control category, turbo-refrigerator capacity controls and an absorption chiller fault diagnostics were investigated. (4) In building mechanical system research fields, eighteen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the user and location awareness technology applied dimming lighting control system, the lighting performance evaluation for light-shelves, the improvement evaluation of air quality through analysis of ventilation efficiency and the evaluation of airtightness of sliding and LS window systems. The subjects of building energy were worked on the energy saving estimation of existing buildings, the developing model to predict heating energy usage in domestic city area and the performance evaluation of cooling applied with economizer control. The studies were also performed related to the experimental measurement of weight variation and thermal conductivity in polyurethane foam, the development of flame spread prevention system for sandwich panels, the utilization of heat from waste-incineration facility in large-scale horticultural facilities.

• Korean Journal of Ichthyology
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• v.32 no.4
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• pp.210-221
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• 2020

Since the introduction of Israeli carp into Korea for farming in 1973, there are no breeding studies on developing Korea Israeli carp (domestic) so far. This study performed gene-based cross-breeding studies to restore genetic diversity of lowered Israeli carp through continuous inbreeding, and for rapid growth and better scales. This study produced four cross-breeding groups (F1) using Koean Israeli carp and Chinese Songpu mirror carp for the improvement of growth and scale of Israeli carp in Korea. And mating scheme for breeding groups was set in consideration of the morphological analysis and genetic distance of broodstock. In addition, this study used microsatellite markers and genotype data to analyze genetic diversity and parentage analysis. As a result, the average N_A and H_E values of Korean select broodstock are 8.3 and 0.743, and F1 is 13.0 and 0.764. This study shows that the genetic diversity of F1 has been recovered over Korean Israeli carp through breeding between Korean Israeli carp and Chinese Songpu mirror carp. Common Israeli carp in Korea reached 1.7 kg in 17 months, and improved Israeli carp reached to 2.2 kg. The KC (Korea×China, KC) group was 2.52 and broodstock group was 3.15. F1 showed lower scale score (0.63) than broodstock. The improved carp (F1; CK, KC) had 20% better scales than the parent group (F0), which improved 27% in weight and 25% in scales compared to common Israeli carp. The Israeli carp developed by the genetics-based breeding grew quicker and had improved genetic diversity and fewer scales, which will be of great value for Korean Israeli aquaculture industry due to good marketability.

• Korean Journal of Heritage: History & Science
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• v.52 no.2
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• pp.240-253
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• 2019

Archaeological heritages are precious cultural relics and public assets that must be preserved, conserved, and shared with people all over the world. Investigating archaeological heritage is valuable and plays an important role for the public good; our ancestors' cultures can be restored, and it helps with developing a clear understanding of the cultural and social aspects of a historical period as well as teaches about historical factors unreported in the literature. One of the most basic and important conditions necessary for recognizing the value and importance of archaeological heritage investigation, expertise, and quality improvement is to establish detailed criteria for investigation services and the qualification examination of archaeological heritage. Observation of detailed criteria and the qualification examination of archaeological heritage can partially demonstrate society's recognition of strengthening transparency, public property, and the objectivity of the investigation of archaeological heritage. However, the detailed criteria for investigation services and the qualification examination of archaeological heritage currently implemented as administrative rules are neither followed by all institutes in the public and private sectors nor the government. Thus, there are serious problems in terms of the effectiveness and stability of institutions. The detailed criteria for the qualification examination breach the principle of statutory reservation, the principle of statutory regulation, and regulations on the announcement and management of orders and rules. Non-compliance with compensation criteria for investigation services or with detailed criteria for the qualification examination of archaeological heritage will be one of the reasons for the failure of the investigation foundation for archaeological heritage in the future. That is, it will result in the expansion, reproduction, and repetition of a vicious cycle of conflict between developers, who are the decision-makers responsible for selecting an investigating organization for archaeological heritage and determining the cost, and investigating organizations. This includes the impractical shortening of investigation periods and reducing costs by developers, distrust of the values and the importance of investigations of archaeological heritage, a decrease in quality, accidents caused by a lack of safety, a lack of occupational ethics, and non-recruitment of new experts, etc. Therefore, it is necessary to change the structure from a vicious cycle to a virtuous cycle, and promote the enactment of regulations that will ensure effectiveness and stability in the process of attaining the goals of the institution and application of the institution, as well as the continuous advancement of work to fill the gaps with reality.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.2
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• pp.169-197
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• 2018

The purpose of this study is to present a reasonable and concrete standard for the Korean aviation insurance compulsory subscription system. Through this, we aim to improve the current revision of laws and regulations, and ultimately create an environment in which the safety and property of the Korean people who use aircraft with appropriate aviation insurance can be secured. In particular, by reviewing the aviation business law and its new laws and regulations enacted in 2017, the legislative improvement direction of aviation insurance will be proposed. In order to maintain the continuous growth of the air transportation industry and to make amicable compensation for the victims, considering the characteristics of the total accident, instantness, and giganticness of air accidents in which a lot of people and property are lost in the event of an accident, adequate insurance coverage is essential. In this respect, the compulsory insurance to amend the principle of freedom of contract, which is the great principle of the modern judicial system, will be persuasive. However, in comparison with foreign legislation, the legal provisions on Korea's obligation to comply with aviation insurance need to be revised around the following issues: First, it is reasonable to enforce the regulation of the mandatory aviation insurance by legislation from the Congress not by administrative regulations. Because it will force the monetary obligations of the individual such as common air carriers. Second, our law regulations respond to various kinds of air damages by using the phrase "limit of liability stipulated in international conventions". However, as we have seen in the text, the range of compensation are various according to the use of legal instruments in international conventions such as the Montreal Convention, which governs the compensation of passengers for damages to passengers today. Third, in countries with narrow territories, such as Korea, there are big differences in flying time and insurable risk between domestic and international transportation. Therefore, it is necessary to divide domestic transportation and international transportation even in the obligation to join the insurance. This dual discipline has the advantage for rookies in air carrier market who mainly start their business from domestic service. Fourth, according to Korean law, the regulations of automobile loss insurance is applicable to the aviation mandatory insurance of unmanned aerial vehicle accident which is lack of persuasion. In the future, it will be appropriate to discipline insurance for unmanned aerial vehicles with unlimited potential for development from a long-term perspective.