• Journal of the Korean Geotechnical Society
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• v.40 no.4
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• pp.49-60
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• 2024

Ground-penetrating radar (GPR) enables rapid data acquisition over extensive areas, but interpreting the obtained data requires specialized knowledge. Numerous studies have utilized numerical analysis methods to examine GPR signal characteristics under various conditions. To develop more realistic numerical models, the heterogeneous nature of the ground, which causes clutter, must be considered. Clutter refers to signals reflected by objects other than the target. The Peplinski material model and fractal techniques can simulate these heterogeneous characteristics, yet there is a shortage of research on the necessary input parameters. Moreover, methods for quantitatively evaluating the similarity between field and analytical data are not well established. In this study, we calculated the autocorrelation coefficient of field data and determined the correlation length using the autocorrelation function. The correlation length represented the temporal or spatial distance over which data exhibited similarity. By comparing the correlation length of field data with that of the numerical model incorporating fractal weights, we quantitatively evaluated a numerical model for heterogeneous ground. Consequently, the results of this study demonstrated a numerical modeling technique that reflected the clutter characteristics of the field through correlation length.

• The Journal of Art Theory & Practice
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• no.4
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• pp.123-144
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• 2006

Foreigners who arrived in Korea after the age of enlightenment were Japanese, Chinese and 'Westerners' who were Europeans and Americans. The westerners were diplomats who visited Korea for colonization or for increasing their economical profits by trading after the spread of imperialism, and tourists curious of back countries, artists, explores and missionaries to perform their roles for their religious beliefs. They contacted with Korean cultural and educational people as missionaries and instructors during Japanese colonial period. In 1945, the allied forces occupied Korea under the name of takeover of Japanese colony after Japan's surrender and the relation between foreigners and Korean cultured men enter upon a new phase. For 3 years, American soldiers enforced lots of systems in Korea and many pro-American people were educated. This relationship lasted even after the establishment of the government of Korean Republic and especially, diplomats called as pro-Korean group came again after Korean War. Among them, there were lots of foreigners interested in cultures and arts. In particular, government officials under American Forces who were influential on political circles or diplomats widened their insights toward Korean cultural assets and collected them a lot. Those who were in Korea from the period of independence to 1950s wrote their impressions about Korean cultural assets on newspapers or journals after visiting contemporary Korean exhibitions. Among them, A. J. McTaggart, Richard Hertz and the Hendersons were dominant. They thought the artists had great interests in compromising and uniting the Orient and the West based on their knowledge of Korean cultural assets and they advised. However, it was different from Korean artist's point of view that the foreigners thought Korean art adhered oriental features and contained western contents. From foreigners' point of view, it is hard to understand the attitude Korean artists chose to keep their self-respect through experiencing the Korean war. It is difficult to distinguish their thought about Korean art based on their exotic taste from the Korean artists' local and peninsular features under Japanese imperialism. We can see their thought about Korean art and their viewpoint toward the third world, after staying in Korea for a short period and being a member of the first world. The basic thing was that they could see the potentialities through the worldwide, beautiful Korean cultural assets and they thought it was important to start with traditions. It is an evidence showing Korean artists' pride in regard to the art culture through experiencing the infringement of their country. By writing about illuminating Korean art from the third party's view, foreigners represented their thoughts through it that their economical, military superiority goes with their cultural superiority. The Korean artist's thought of emphasizing Korean history and traditions, reexamining and using it as an original creation may have been inspired by westerners' writings. 'The establishment of national art' that Korean artists gave emphasis then, didn't only affect one of the reactions toward external impact, 'the adhesion of tradition'. In the process of introducing Korean contemporary art and national treasure in America, different view caused by role differences-foreigner as selector and Korean as assistant-showed the fact evidently that the standard of beauty differed between them. By emphasizing that the basis to classify Korean cultural assets is different from the neighborhood China and Japan, they tried to reflect their understanding that the feature of Korean art is on speciality other than universality. And this make us understand that even when Korean artists profess modernism, they stress that the roots are on Korean and oriental tradition. It was obviously a different thought from foreigners' view on Korean art that Korean artists' conception of modernism and traditional roots are inherent in Korean history. In 1950s, after the independence, Korea had different ideas from foreigners that abstract was to be learned from the west. Korea was enduring tough times with their artists' self-respect which made them think that they can learn the method, but the spirit of abstract is in the orient.

• Journal of Preventive Medicine and Public Health
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• v.15 no.1
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• pp.33-46
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• 1982

In Korea BCG vaccination has been employed as the main control measure for tuberculosis since 1962. Recently, the protective efficacy of BCG against tuberculosis has been controversial worldwide. A case-control study was conducted to evaluate the efficacy of BCG in Korea which has a high prevalence of tuberculosis(2.5%). The study subjects were children under the age of 14 years who were hospitalized and diagnosed as tuberculosis in three general hospitals in Taegu City during last 6 years ($1975{\sim}1980$). Among 416 hospitalized tuberculous patients, 314 cases were confirmed as to the presence or absence of the BCG scar. A control group was selected from the same hospital patients of the same period as the cases. The control group was other than tuberculous patients whose distribution of age, sex and residence were the same as the cases. The results obtained are as follows: For all forms of tuberculosis, the relative risk and the protective efficacy of BCG were 3.5 and 71.8%. The efficacy was higher among female than among male (78.6% vs. 65.8%). The efficacy was higher among the one year and above than among less than 1 year of age. For tuberculous meningitis, the relative risk and the protective efficacy of BCG were 3.9 and 74.3 %. The efficacy was statistically significantly higher among female than among male (p<0.05). The relative risk and the protective efficacyt of BCG for uberculous meningitis combined with miliary tuberculosis and combined with pulmonary tuberculosis represented 6.9, 85.6%, and 7.4, 86.5%, respectively. On the other hand, the relative risk and the protective efficacy of BCG for miliary tuberculosis were 2.1 and 51.6%, and for pulmonary tuberculosis, 2.3 and 54.7%, respectively. From these results, it appears that BCG vaccination is an efficient preventive measure in Korea where tubercluosis is prevalent. Thus the routine BCG vaccination should be continued.

• Restorative Dentistry and Endodontics
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• v.31 no.5
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• pp.398-408
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• 2006

The purpose of this study was to verify the usefulness of MTT analysis as a tool of measurement of the periodontal ligament cell viability from the extracted rat molar. A total of 80 Sprague-Dawley white female rat of 4 week-old with a body weight of 100 grams were used. The maxillary left and right, first and second molars were extracted under Ketamine anesthesia. Twenty-four teeth of each group (divided as five groups depending upon the time-lapse after extraction such as Immediate, 10, 20, 40 and 60 minutes) were immersed in $200{\mu}l$ of MTT solution (0.5 mg/ml) and processed for optical density measurements. Another 10 teeth of each group were treated as same as above and sectioned at $10{\mu}m$ for microscopic examination. All measurements values were divided by the value of hematoxylin-eosin staining which represented the volume of each corresponding samples. Immediate and 10 minute groups showed highest MTT values followed by 20, 40, and 60 minutes consecutively. Statistical significance (p<0.05) existed between all groups except in immediate versus 10 minute groups and 40 versus 60 minutes. Histological findings also showed similar findings with MTT results in crystal shape and crystal numbers between the experimental groups. These data indicate that in vivo MTT analysis nay be of value for evaluation of the periodontal ligament cell viability without time- consuming cell culturing processes.

• Journal of Internet Computing and Services
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• v.16 no.2
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• pp.49-55
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• 2015

According to the statistics of traffic accidents over recent 5 years, traffic accidents during the night times happened more than the day times. There are various causes to occur traffic accidents and the one of the major causes is inappropriate or missing street lights that make driver's sight confused and causes the traffic accidents. In this paper, with smartphones, we designed and implemented a lane luminance measurement application which stores the information of driver's location, driving, and lane luminance into database in real time to figure out the inappropriate street light facilities and the area that does not have any street lights. This application is implemented under Native C/C++ environment using android NDK and it improves the operation speed than code written in Java or other languages. To measure the luminance of road, the input image with RGB color space is converted to image with YCbCr color space and Y value returns the luminance of road. The application detects the road lane and calculates the road lane luminance into the database sever. Also this application receives the road video image using smart phone's camera and improves the computational cost by allocating the ROI(Region of interest) of input images. The ROI of image is converted to Grayscale image and then applied the canny edge detector to extract the outline of lanes. After that, we applied hough line transform method to achieve the candidated lane group. The both sides of lane is selected by lane detection algorithm that utilizes the gradient of candidated lanes. When the both lanes of road are detected, we set up a triangle area with a height 20 pixels down from intersection of lanes and the luminance of road is estimated from this triangle area. Y value is calculated from the extracted each R, G, B value of pixels in the triangle. The average Y value of pixels is ranged between from 0 to 100 value to inform a luminance of road and each pixel values are represented with color between black and green. We store car location using smartphone's GPS sensor into the database server after analyzing the road lane video image with luminance of road about 60 meters ahead by wireless communication every 10 minutes. We expect that those collected road luminance information can warn drivers about safe driving or effectively improve the renovation plans of road luminance management.

• KDI Journal of Economic Policy
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• v.12 no.1
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• pp.31-68
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• 1990

The concentration of economic power takes the form of one or a few firms controlling a substantial portion of the economic resources and means in a certain economic area. At the same time, to the extent that these firms are owned by a few individuals, resource allocation can be manipulated by them rather than by the impersonal market mechanism. This will impair allocative efficiency, run counter to a decentralized market system and hamper the equitable distribution of wealth. Viewed from the historical evolution of Western capitalism in general, the concentration of economic power is a paradox in that it is a product of the free market system itself. The economic principle of natural discrimination works so that a few big firms preempt scarce resources and market opportunities. Prominent historical examples include trusts in America, Konzern in Germany and Zaibatsu in Japan in the early twentieth century. In other words, the concentration of economic power is the outcome as well as the antithesis of free competition. As long as judgment of the economic system at large depends upon the value systems of individuals, therefore, the issue of how to evaluate the concentration of economic power will inevitably be tinged with ideology. We have witnessed several different approaches to this problem such as communism, fascism and revised capitalism, and the last one seems to be the only surviving alternative. The concentration of economic power in Korea can be summarily represented by the "jaebol," namely, the conglomerate business group, the majority of whose member firms are monopolistic or oligopolistic in their respective markets and are owned by particular individuals. The jaebol has many dimensions in its size, but to sketch its magnitude, the share of the jaebol in the manufacturing sector reached 37.3% in shipment and 17.6% in employment as of 1989. The concentration of economic power can be ascribed to a number of causes. In the early stages of economic development, when the market system is immature, entrepreneurship must fill the gap inherent in the market in addition to performing its customary managerial function. Entrepreneurship of this sort is a scarce resource and becomes even more valuable as the target rate of economic growth gets higher. Entrepreneurship can neither be readily obtained in the market nor exhausted despite repeated use. Because of these peculiarities, economic power is bound to be concentrated in the hands of a few entrepreneurs and their business groups. It goes without saying, however, that the issue of whether the full exercise of money-making entrepreneurship is compatible with social mores is a different matter entirely. The rapidity of the concentration of economic power can also be traced to the diversification of business groups. The transplantation of advanced technology oriented toward mass production tends to saturate the small domestic market quite early and allows a firm to expand into new markets by making use of excess capacity and of monopoly profits. One of the reasons why the jaebol issue has become so acute in Korea lies in the nature of the government-business relationship. The Korean government has set economic development as its foremost national goal and, since then, has intervened profoundly in the private sector. Since most strategic industries promoted by the government required a huge capacity in technology, capital and manpower, big firms were favored over smaller firms, and the benefits of industrial policy naturally accrued to large business groups. The concentration of economic power which occured along the way was, therefore, not necessarily a product of the market system. At the same time, the concentration of ownership in business groups has been left largely intact as they have customarily met capital requirements by means of debt. The real advantage enjoyed by large business groups lies in synergy due to multiplant and multiproduct production. Even these effects, however, cannot always be considered socially optimal, as they offer disadvantages to other independent firms-for example, by foreclosing their markets. Moreover their fictitious or artificial advantages only aggravate the popular perception that most business groups have accumulated their wealth at the expense of the general public and under the behest of the government. Since Korea stands now at the threshold of establishing a full-fledged market economy along with political democracy, the phenomenon called the concentration of economic power must be correctly understood and the roles of business groups must be accordingly redefined. In doing so, we would do better to take a closer look at Japan which has experienced a demise of family-controlled Zaibatsu and a success with business groups(Kigyoshudan) whose ownership is dispersed among many firms and ultimately among the general public. The Japanese case cannot be an ideal model, but at least it gives us a good point of departure in that the issue of ownership is at the heart of the matter. In setting the basic direction of public policy aimed at controlling the concentration of economic power, one must harmonize efficiency and equity. Firm size in itself is not a problem, if it is dictated by efficiency considerations and if the firm behaves competitively in the market. As long as entrepreneurship is required for continuous economic growth and there is a discrepancy in entrepreneurial capacity among individuals, a concentration of economic power is bound to take place to some degree. Hence, the most effective way of reducing the inefficiency of business groups may be to impose competitive pressure on their activities. Concurrently, unless the concentration of ownership in business groups is scaled down, the seed of social discontent will still remain. Nevertheless, the dispersion of ownership requires a number of preconditions and, consequently, we must make consistent, long-term efforts on many fronts. We can suggest a long list of policy measures specifically designed to control the concentration of economic power. Whatever the policy may be, however, its intended effects will not be fully realized unless business groups abide by the moral code expected of socially responsible entrepreneurs. This is especially true, since the root of the problem of the excessive concentration of economic power lies outside the issue of efficiency, in problems concerning distribution, equity, and social justice.