• Economic and Environmental Geology
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• v.36 no.3
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• pp.159-170
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• 2003

Heavy metals are extracted from Chonju stream sediment, roadside soils and sediments along Honam expressway, soils and tailings from mining area using three different methods (partial extraction in Standard Method, partial extraction method with maintaining 0.1 N of extraction solution and Sequential Extraction Method). In samples having buffer capacity against acid, pH 1 (0.1 N HCl) of extraction solution can not be maintained and pH of extraction solution increases up to 8.0 when partial extraction in Standard Method is used. The averages and ranges of HPE(heavy metals extracted using partial extraction in Standard Method)/HPEM(heavy metals extracted using partial extraction method with maintaining 0.1 N of extraction solution) values are 0.479 and 0.145~0.929 for Cd, 0.534 and 0.078~0.928 for Zn, 0.432 and 0.041~0.992 for Mn, 0.359 and 0.011~0.874 for Cu, 0.150 and 0.018~0.530 for Cr, 0.219 and 0.003~0.853 for Pb, and 0.088 and 1.73${\times}$10$^{-5}$~0.303 for Fe. These data indicate that the difference between HPE and HPEM is large in the order of Fe, Cr, Pb, Cu, Mn, Cd and Zn. The amounts of heavy metals extracted decreases in the follow order; Sum III(sum of fraction I, II, III in sequential extraction)>HPEM>Sum III (sum of fraction I and II)>HPE for Zn, Cd and Mn and Sum III>HPEM>HPE for Cr and Fe. In the case Cr, Sum II is lower than HPEM and higher than HPE. In case of Cu, extracted heavy metals is large in the order Sum IV>HPEM>Sum III HPE. HPE/HPEM value decreases with increasing the amount of HCl used for maintaining 0.1 N of extraction solution. For samples with high buffer capacity, HPE/HPEM value in all elements is lower than 0.2. On the other hand, for samples with low buffer capacity, HPE/HPEM value are over 0.2 and many samples have values higher than 0.6 for Zn, Cd Mn and Cu due to the small difference between Sum II and Sum III, and relatively higher mobility. However, for Fe and Cr, HPE/HPEM value is below 0.2 even for samples with low buffer capacity due to their low mobility and big difference between Sum II and Sum III. This study indicates that the partial extraction method in Korean Standard Method of soil is not suitable for an assessment of soil contamination in area where buffer capacity of soil can be decreased or lost because of a long term exposure to environmental damage such as acidic rain.

• Journal of Sericultural and Entomological Science
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• v.9
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• pp.67-87
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• 1969

1. Objectives and Importance. Many silkworms have been damaged by nuclear polyhedrosis virus diseases thoughout the country every year causing a decease in cocoon production by approximately ten per cent per year. The damage caused by the infections virus has occured in spite of complete disinfection. In this respect, it is well known it is impossible, at the present time, to protect the silkworm from these virus infections through chemical and physical control methods. Therefore, this author has attempted to solve this urgent problem from the view point of heredity and breeding, discovering the different resistances and heritabilities among 120 stains collected from throughout the country, and selecting the ones with highest resistance for the basic materials in the silkworm breeding. 2. Results of work 1) The strains with strong resistance to the nuclear polyhedrosis virus diseases are N$_4$, N$\sub$15/, N$\sub$48/, C$\sub$55/ and Em. the log ED$\sub$50/ values of them vary between 0.799 and 1.611. The susceptible strains are N$\sub$20/, C$\sub$62/, N$\sub$76/, N$\sub$79/ and C$\sub$108/, the log ED$\sub$50/ values of them vary between 5.159 and 7.258. (Reference Table 4) The Japanese strain with a log ED$\sub$50/, value of 3.770 is the strongest, followed by the Chinese strain with a log ED$\sub$50/ value of 3.564. The weakest is the European strain with a log ED$\sub$50/ value of 3.3381. The direction coefficient of the regression equation of the susceptibility varies between 0.1 and 0.6, the uniformness of the resistance of the preserved strains of this country is comparatively low. The hereditary henomena of the resistance of each strain and the conerete method of its application for silkworm breeding main the subjects for later studies. 2) The content of water and ash in silkworm has not been correlated with the capability for resistance to the virus diseases(Reference. Table 8). but it is very significantly correlated with mortality rate (in common reaning). In the case of the silkworms which have just completed the fourth moulting the content of water and ash is not related to the mortality rate. In the case of the silkworms which have just completed the third moulting, however, the water( +0.326) and ash (+0.362) registered a high significance. The ash content in the first ($\div$0.520) and second ($\div$0.386) moults is highly significant but water content in both cases is not significant (Reference Table 7). 3) The No. 205 strain proved to be the best in character among the various F$_1$ hybrids. No. 204 was very good in strength but a little lower in cocoon character than the control. No. 212 was a little low in coccon character and mortality was average, but the cocoon harvest was the best among all the varieties offered for (Reference Table 9). 4), In short, the above mentioned strains which are known to have strong resistance to the virus disease are expected to provide basic data for breeding strong varieties. It is proposed that continued research should be conducted on the characteristics of various strains for a satisfactory preservation of various characteristics.research should be conducted on the characteristics of various strains for a satisfactory preservation of various characteristics.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.5
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• pp.536-544
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• 2001

Three harmful algal bloom species with similar morphology, Cochlodinium polykrikoides, Gyodinium impudicum and Gymodinium catenatum have damaged to aquatic animals or human health by either making massive blooms or intoxication of shellfishes in a food chain. Eco-physiological and hydrodynamic studies on the harmful algae offer useful informations in the understanding their bloom mechanism by giving promising data for the prediction and modelling of harmful algal blooms event. Thus, we studied the abundance of these species in the coastal area of South Sea of Korea and their effects of temperature, salinity, irradiance and nutrient on the growth for the isolates. The timing for initial appearance of the three species around the coastal area of Namhaedo, Narodo and Wando was between Bate July and late August in 1999 when water temperature ranged from $22.8^{\circ}C\;to\;26.5^{\circ}C$ Vegetative cells of C. polykrikoides and G. impudicum were abundant until late September when water temperature had been dropped to less than $23^{\circ}C$. By contrast, vegetative cell of G. catenatum disappeared before early September, showing shorter period of abundance than the other two species in the South Sea. Both G. impudicum and G. catenatum revealed comparatively low density with a maximal cell density of 3,460 cells/L and 440 cells/L, respectively without making any bloom, while C. polykrikoides made massive blooms with a maximal cell density more than $40\times10^6$cells/L, The three species showed a better growth at the relatively higher water temperature ranging from 22 to $28^{\circ}C$ with their maximal growth rate at $25^{\circ}C$ in culture, which almost corresponded with the water temperature during the outbreak of C. polykrikoides in the coastal area of South Sea. Also, they all showed a relatively higher growth at the salinity from 30 to $35\%$. Specially, G. impudicum showed the euryhalic characteristics among the species, On the other hand, growth rate of G. catenatum decreased sharply with the increase of water temperature at the experimental ranges more than $35\%$. The higher of light intensities showed the better growth rates for the three species, Moreover, C. polykrikoides and G. impudirum continued their exponential growth even at 7,500 lux, the highest level of light intensity in the experiment, Therefore, It is assumed that C. polykrikoides has a physiological capability to adapt and utilize higher irradiance resulting in the higher growth rate without any photo inhibition response at the sea surface where there is usually strong irradiance during its blooming season. Although C. poiykikoides and G. impudicum continued their linear growth with the increase of nitrate ($NO_3^-$) and ammonium ($NH_4^-$) concentrations at less than the $40{\mu}M$, they didn't show any significant differences in growth rates with the increase of nitrate and ammonium concentrations at more than $40{\mu}M$, signifying that the nitrogen critical point for the growth of the two species stands between 13.5 and $40{\mu}M$. Also, even though both of the two species continued their linear growth with the increase of phosphate ($PO_4^{2-}$) concentrations at less than the $4.05{\mu}M$, there were no any significant differences in growth rates with the increase of phosphate concentrations at more than $4.05{\mu}M$, signifying that the phosphate critical point for the growth of the two species stands between 1.35 and $4.05{\mu}M$. On the other hand, C. polykrikoides has made blooms at the oligotrophic environment near Narodo and Namhaedo where the concentration of DIN and DIP are less than 1.2 and $0.3{\mu}M$, respectively. We attributed this phenomenon to its own ecological characteristics of diel vertical migration through which C. polykrikoides could uptake enough nutrients from the deep sea water near bottom during the night time irrespective of the lower nutrient pools in the surface water.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.1
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• pp.2206-2217
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• 1971

Spillway and discharge channel of reservoirs require the Control of Large volume of water under high pressure. The energies at the downstream end of spillway or discharge channel are tremendous. Therefore, Some means of expending the energy of the high-velocity flow is required to prevent scour of the riverbed, minimize erosion, and prevent undermining structures or dam it self. This may be accomplished by Constructing an energy dissipator at the downstream end of spillway or discharge channel disigned to dissipated the excessive energy and establish safe flow Condition in the outlet channel. There are many types of energy dissipators, stilling basins are the most familar energy dissipator. In the stilling basin, most energies are dissipated by hydraulic jump. stilling basins have some length to cover hydraulic jump length. So stilling basins require much concrete works and high construction cost. Flip bucket type energy dissipators require less construction cost. If the streambed is composed of firm rock and it is certain that the scour will not progress upstream to the extent that the safety of the structure might be endangered, flip backet type energy dissipators are the most recommendable one. Following items are tested and studied with bucket radius, $R=7h_2$,(medium of $4h_2{\geqq}R{\geqq}10h_2$). 1. Allowable upstream channel slop of bucket. 2. Adequate bucket lip angle for good performance of flip bucket. Also followings are reviwed. 1. Scour by jet flow. 2. Negative pressure distribution and air movement below nappe flow. From the test and study, following results were obtained. 1. Upstream channel slope of bucket (S=H/L) should be 0.25<H/L<0.75 for good performance of flip bucket. 2. Adequated lip angle $30^{\circ}{\sim}40^{\circ}$ are more reliable than $20^{\circ}{\sim}30^{\circ}$ for the safety of structures.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.3
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• pp.141-151
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• 1979

To investigate the relationship between the effect of potassium basal and top dressing amount on rice plant under the limed condition, a pot experiment was conducted with Milyang 21, rice variety. Growing status, yield components and chemical component of rice, plant were determined and soils were analyzed along with the growing stages and obtained results are as follows. 1. Control treatment, without lime application shows a good vegetative growth as compared with lime treated one. However grain yield was higher in lime treated pot when potassium was applied as basal and top dressing. 2. There was no big difference between potassium applied and control treatment on growing status of nice plant until 20 days after transplanting. However in case of lime treated pot big difference were observed 20 days after transplanting resulting lower grain yield as compared with control treatment. This trend were severe in a lime treated treatment. 3. In control treatment, potassium basal dressing shows higher grain yield as increase the amount of basal dressing and the highest yield obtained in all basal potassium application treatment. However in case of lime treated pot when two-third of potassium were applied as basal dressing, potassium content of rice became lower at reproductive stage and resulted lower yield. When we applied all the potassium as a basal dressing, there were no differences as compared with control treatment in terms of grain yield. 4. The soil condition that affects potassium absorption disorder in rice plant such as unlimed condition, potassium application should be done as a basal dressing. However in limed condition that potassium absorption disorder occurs scarcely, and potassium content exists unsufficient amount in soil, large amount of potassium as basal dressing and the rest as top dressing are recommended. 5. The higher content of potassium in rice plant at the reproductive growing stage results heavier tillers as compared with lower one so that heavier tillers produce more grain yield. 6. At vigorous growing stage there was a positive correlation between electric conductivity of soil and amount of potasium absorbed by rice plant. This fact suggests that to obtain higher yield large amount of potassium top dressing at late of vegetative growing stage are necessary so that the content of potassium in rice plant will increase and results higher yield.

• Journal of Sericultural and Entomological Science
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• v.47 no.2
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• pp.68-77
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• 2005

A characteristic of subtropical zones region MK-T2 compares with an gaeryangppong, and the 9-10 schedule the times when a leaf blooms to are fast, and ratio that a branch edge by the colds becomes lean showed 5.7%, and a growth of the new branch which went out delivers 67.2 cm, mulberry loaves of the new branch which went out, and 18.6, a form of a leaf is the 1.10 that length of a leaf grew more a bit than width of a leaf up. Thickness of a leaf is $228.2{\mu}m$, and an area is more similar than gaeryangppong as $225.6cm^2$. in plant taxonomy, the hair whom the style exists short with 0.7 mm, and go to the pistil head inside so as to be rare is distributed, and belong to Dolichostylae Pubescentes. The new branch cutting which executed without remedy processes was independent of a thickness of a case branch, and the form and 100% root was said, and an gaeryangppong compared with the fact that 10% root went out of 15 mm ideal, and was excellent very, and looked, a root went out a root the soil and water, all showed a characteristic to go out at central of a branch bases at 45% ratio. Length was 24.6 mm, and were water rate 78.8%, and mulberry of MK-T2 was carrying together sweetness and acidity to pH 4.7 while, besides, arrival was 19.21 Brix%. A larva period and pupa ratio, cocoon thickness ratio are almost similar to gaeryangppong, or weight of one cocoon, cocoon thickness, 20,002 cocoon quantity shows some results to drop, and be soft of a leaf, and feed value certifications are comparatively top-ranking. As a result of having analyzed amino acid of the 3rd day of 5th silkworm larva which bred to MK-T2, a collation absorbing an gaeryangppong went, and looked, but compared with a collation in case of tests to eat MK-T2, and looked, and the lie collations were not detected a difference at Leu, but MK-T2 tests were detected mutual almost similar amino acid creation. medical efficacy of the 3rd day of 5th silkworm larva ethanol extract which bred to MK-T2 and black results, histologic a case did not appear at HE dyeing about the kidney organization which extracted form the rats which ate a silkworm ethanol extract and dyeing all chemical organization immunity, and one step protein revelation became lower with almost unidentified levels.

• Journal of Korean Society of Forest Science
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• v.83 no.3
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• pp.331-343
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• 1994

This study was conducted to find out the effect of $SO_2$ gas on growth of tree species and the effect of pretreatment of ABA to Pinus koraiensis. Abies holophylla and Taeus cuspidata on the susceptibility for $SO_2$ gas damage. The survey was carried out on the water contents of leaf and shoot, and the acidities of bark and leaf, and the chlorophyll and water soluble sulfur contents, and the changes of transpiration rates on selected seedlings exposed to $SO_2$ gas at seven levels : 0ppm, 0.5ppm, 1ppm, 2ppm, 4ppm, 26.4ppm ABA, 56.8ppm ABA. The results obtained from this research are as follows : 1. The water contents of leaf and shoot of the three tree species decreased with increasing concentrations of $SO_2$ gas and the relative susceptibility of Abies holophylla was larger than those of Taxus cuspidata and Pinus koraiensis because moisture diminution rates were higher in leaves and shoots of Abies holophylla than those of other species. 2. The acidities of bark and leaf of the three tree species increased with increasing concentrations of $SO_2$ gas. The relative susceptibility of Pinus koraiensis in bark acidity was larger than those of Abies holopfaylla and Toxus cuspidata. Abies holophylla was more susceptive than Pinus koraiensis and Taxus cuspidata. 3. Water soluble sulfur contents of the three tree species increased with increasing concentration of $SO_2$ gas. The relative susceptibility of Taxus cuspidata in water soluble sulfur contents was lager than those of Pinus koraiensis and Abies holophylla. 4. Leaf chlorophyll contents of the three tree species decreased with increasing concentrations of $SO_2$ gas. The order of the relative susceptibility in leaf chlorophyll contents was Taxus cuspidata, Abies holophylla and Pinus koraiensis. 5. Correlation coefficients among the measurement were highly significant for $SO_2$ treatment in all three tree species. 6. The transpiration rates of Abies holophylla and Taxus cuspidata did not change until up to 220 minutes after initiation of $SO_2$ gas fumigation, and changed a little during the time between 220 minutes and 270 minutes. On the other hand, Pinus koraiensis continued to change in transpiration rates little by little from the start of $SO_2$ gas treatment up to 270 minutes, meaning that Pinus koraiensis is less sensitive to ABA. 7. When 2ppm of $SO_2$ was treated. ABA pretreatment effect was detected on the six measurement parameters. ABA affected the resistance of plants by inducing stomata closure. 8. The order of relative susceptibility of the three tree species to $SO_2$ gas fumigation was Abies holophylla, Taxus cuspidata and Pinus koraiensis. Pinus koraiensis was more resistant to $SO_2$ gas than Abies holophylla and Taxus cuspidata.

• Journal of Korean Society of Forest Science
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• v.84 no.3
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• pp.286-298
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• 1995

This study was carried out to investigate the effect of forest soil acidification on the distribution of exchangeable cations($Ca^{2+}$, $Mg^{2+}$, $Al^{3+}$) and heavy metals(Cu, Zn, Mn, Pb, Cd) in soil, and to understand the relation of the soil chemical properties and the distribution of nutrients and hear metals in fine root and foliage. The results through survey on the long - term change of soil pH and the contents of nutrient and heavy metal in soil, fine root and foliage by 2 sites near Ulsan - Onsan industrial estate and 2 sites in limited development district are summarized as follows : 1. The average forest soil pH(A horizon) in Ulsan had been proceeded down to 3.73 in deciduous forest and 3.86 in coniferous forest in 1994 from 4.45 and 4.78 in 1987, respectively, which indicated serious soil acidification. As comparing soil pH among sites, Dongcheon coniferous forest(pH 4.57) in limited development district showed the highest values and Dangwol deciduous forest(pH 3.19) near Onsan industrial estate showed the lowest values in 1994. 2. Contents of exchangeable calcium in forest soils of limited development district where showed much higher soil pH than industrial estate were 3.5 times more in deciduous forest soil and 11 times more in coniferous forest soil than in industrial estate, and contents of exchangeable magnesium were also 4.5 and 5 times more in limited development district than in industrial estate, respectively. However contents of exchangeable aluminium which had been supposed more in forest soil of industrial estate were more in limited development district. 3. Contents of calcium and magnesium in fine root of deciduous trees(A hirsuta. Q. acutissima) were 3.6 and 1.7 times more in limited development district than in industrial estate, respectively, and those of coniferous trees(P. rigida, P. thunbergii) were 4.6 and 1.5 times more in Limited development district than in industrial estate, respectively. Also contents of calcium and magnesium in foliage of deciduous trees were 1.1 and 2.2 times more in limited development district than in industrial estate, respectively, and those of coniferous trees were 1.8 and 3.3 times more in limited development district, respectively. And contents of aluminium in fine root and foliage were nearly as same as in soil. 4. Ca/Al molar ratios in soil and fine root, which could be related with the dgree of soil acidification and Al toxicity on trees, were Less than 1 in all sites except Dongcheon, suggesting that the soil and fine root in the sites have high sensitivity to soil acidification and the decrease in nutrient uptake and root enlargement. The Ca/Al molar ratios in soil and fine root in coniferous forest were highly correlated with the soil pH one another. 5. Contents of Cu, Zn and Pb in soil, fine root and foliage were more in industrial estate than in limited development district in both deciduous and coniferous forests, however, oppositely contents of Mn and Cd in soil were more in limited development district than in industrial estate.

• Korean Security Journal
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• no.39
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• pp.185-215
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• 2014

Since North Korea has used terror crime as a means of unification under communism against South Korea, South Korea has been much damaged until now. And the occurrence possibility of terror crime by North Korean authority is now higher than any other time. The North Korean terror crimes of Kim Il Sung era had been committed by the dictator's instruction with the object of securing governing fund. However, looking at the terror crimes committed for decades during Kim Jung Il authority, it is revealed that these terror crimes are expressed as a criminal behavior because of the conflict to accomplish the power and economic advantage non powerful groups target. This study focused on the power conflict in various causes of terror crimes by applying George B. Vold(1958)'s theory which explained power conflict between groups became a factor of crime, and found the aspect by ages of terror crime behavior by North Korean authority and responding plan to future North Korean terror crime. North Korean authority high-ranking officials were the Labor Party focusing on Juche Idea for decades in Kim Il Sung time. Afterwards, high-ranking officials were formed focusing on military authorities following Military First Policy at the beginning of Kim Jung Il authority, rapid power change has been done for recent 10 years. To arrange the aspect by times of terror crime following this power change, alienated party executives following the support of positive military first authority by Kim Jung Il after 1995 could not object to forcible terror crime behavior of military authority, and 1st, 2nd Yeongpyeong maritime war which happened this time was propelled by military first authority to show the power of military authority. After 2006, conservative party union enforced censorship and inspection on the trade business and foreign currency-earning of military authority while executing drastic purge. The shooting on Keumkangsan tourists that happened this time was a forcible terror crime by military authority following the pressure of conservative party. After October, 2008, first military reign union executed the launch of Gwanmyungsung No.2 long-range missile, second nuclear test, Daechung marine war, and Cheonanham attacking terror in order to highlight the importance and role of military authority. After September 2010, new reign union went through severe competition between new military authority and new mainstream and new military authority at this time executed highly professionalized terror crime such as cyber/electronic terror unlike past military authority. After July 2012, ICBM test launch, third nuclear test, cyber terror on Cheongwadae homepage of new mainstream association was the intention of Km Jung Eun to display his ability and check and adjust the power of party/military/cabinet/ public security organ, and he can attempt the unexpected terror crime in the future. North Korean terror crime has continued since 1980s when Kim Jung Il's power succession was carried out, and the power aspect by times has rapidly changed since 1994 when Kim Il Sung died and the terror crime became intense following the power combat between high-ranking officials and power conflict for right robbery. Now South Korea should install the specialized department which synthesizes and analyzes the information on North Korean high-ranking officials and reinforce the comprehensive information-collecting system through the protection and management of North Korean defectors and secret agents in order to determine the cause of North Korean terror crime and respond to it. And South Korea should participate positively in the international collaboration related to North Korean terror and make direct efforts to attract the international agreement to build the international cooperation for the response to North Korean terror crime. Also, we should try more to arrange the realistic countermeasure against North Korean cyber/electronic terror which was more diversified with the expertise terror escaping from existing forcible terror through enactment/revision of law related to cyber terror crime, organizing relevant institute and budget, training professional manpower, and technical development.

• Korean Security Journal
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• no.18
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• pp.169-190
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• 2009

Today, the rapid advance of scientific technologies has brought about fundamental changes to the types and levels of terrorism while the war against the world more than one thousand small and big terrorists and crime organizations has already begun. A method highly likely to be employed by terrorist groups that are using 21st Century state of the art technology is cyber terrorism. In many instances, things that you could only imagine in reality could be made possible in the cyber space. An easy example would be to randomly alter a letter in the blood type of a terrorism subject in the health care data system, which could inflict harm to subjects and impact the overturning of the opponent's system or regime. The CIH Virus Crisis which occurred on April 26, 1999 had significant implications in various aspects. A virus program made of just a few lines by Taiwanese college students without any specific objective ended up spreading widely throughout the Internet, causing damage to 30,000 PCs in Korea and over 2 billion won in monetary damages in repairs and data recovery. Despite of such risks of cyber terrorism, a great number of Korean sites are employing loose security measures. In fact, there are many cases where a company with millions of subscribers has very slackened security systems. A nationwide preparation for cyber terrorism is called for. In this context, this research will analyze the current status of Korea's cyber security systems and its laws from a policy perspective, and move on to propose improvement strategies. This research suggests the following solutions. First, the National Cyber Security Management Act should be passed to have its effectiveness as the national cyber security management regulation. With the Act's establishment, a more efficient and proactive response to cyber security management will be made possible within a nationwide cyber security framework, and define its relationship with other related laws. The newly passed National Cyber Security Management Act will eliminate inefficiencies that are caused by functional redundancies dispersed across individual sectors in current legislation. Second, to ensure efficient nationwide cyber security management, national cyber security standards and models should be proposed; while at the same time a national cyber security management organizational structure should be established to implement national cyber security policies at each government-agencies and social-components. The National Cyber Security Center must serve as the comprehensive collection, analysis and processing point for national cyber crisis related information, oversee each government agency, and build collaborative relations with the private sector. Also, national and comprehensive response system in which both the private and public sectors participate should be set up, for advance detection and prevention of cyber crisis risks and for a consolidated and timely response using national resources in times of crisis.