• Asia Marketing Journal
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• v.14 no.2
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• pp.157-176
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• 2012

Brand switching data frequently used in market structure analysis is adequate to analyze non- durable goods, because it can capture competition between specific two brands. But brand switching data sometimes can not be used to analyze goods like automobiles having long term duration because one of main assumptions that consumer preference toward brand attributes is not changed against time can be violated. Therefore a new type of data which can precisely capture competition among durable goods is needed. Another problem of using brand switching data collected from actual purchase behavior is short of explanation why consumers consider different set of brands. Considering above problems, main purpose of this study is to analyze market structure for durable goods with consideration set. The author uses exploratory approach and latent class clustering to identify market structure based on heterogeneous consideration set among consumers. Then the relationship between some factors and consideration set formation is analyzed. Some benefits and two demographic variables - age and income - are selected as factors based on consumer behavior theory. The author analyzed USA automotive market with top 11 brands using exploratory approach and latent class clustering. 2,500 respondents are randomly selected from the total sample and used for analysis. Six models concerning market structure are established to test. Model 1 means non-structured market and model 6 means market structure composed of six sub-markets. It is exploratory approach because any hypothetical market structure is not defined. The result showed that model 1 is insufficient to fit data. It implies that USA automotive market is a structured market. Model 3 with three market structures is significant and identified as the optimal market structure in USA automotive market. Three sub markets are named as USA brands, Asian Brands, and European Brands. And it implies that country of origin effect may exist in USA automotive market. Comparison between modal classification by derived market structures and probabilistic classification by research model was conducted to test how model 3 can correctly classify respondents. The model classify 97% of respondents exactly. The result of this study is different from those of previous research. Previous research used confirmatory approach. Car type and price were chosen as criteria for market structuring and car type-price structure was revealed as the optimal structure for USA automotive market. But this research used exploratory approach without hypothetical market structures. It is not concluded yet which approach is superior. For confirmatory approach, hypothetical market structures should be established exhaustively, because the optimal market structure is selected among hypothetical structures. On the other hand, exploratory approach has a potential problem that validity for derived optimal market structure is somewhat difficult to verify. There also exist market boundary difference between this research and previous research. While previous research analyzed seven car brands, this research analyzed eleven car brands. Both researches seemed to represent entire car market, because cumulative market shares for analyzed brands exceeds 50%. But market boundary difference might affect the different results. Though both researches showed different results, it is obvious that country of origin effect among brands should be considered as important criteria to analyze USA automotive market structure. This research tried to explain heterogeneity of consideration sets among consumers using benefits and two demographic factors, sex and income. Benefit works as a key variable for consumer decision process, and also works as an important criterion in market segmentation. Three factors - trust/safety, image/fun to drive, and economy - are identified among nine benefit related measure. Then the relationship between market structures and independent variables is analyzed using multinomial regression. Independent variables are three benefit factors and two demographic factors. The result showed that all independent variables can be used to explain why there exist different market structures in USA automotive market. For example, a male consumer who perceives all benefits important and has lower income tends to consider domestic brands more than European brands. And the result also showed benefits, sex, and income have an effect to consideration set formation. Though it is generally perceived that a consumer who has higher income is likely to purchase a high priced car, it is notable that American consumers perceived benefits of domestic brands much positive regardless of income. Male consumers especially showed higher loyalty for domestic brands. Managerial implications of this research are as follow. Though implication may be confined to the USA automotive market, the effect of sex on automotive buying behavior should be analyzed. The automotive market is traditionally conceived as male consumers oriented market. But the proportion of female consumers has grown over the years in the automotive market. It is natural outcome that Volvo and Hyundai motors recently developed new cars which are targeted for women market. Secondly, the model used in this research can be applied easier than that of previous researches. Exploratory approach has many advantages except difficulty to apply for practice, because it tends to accompany with complicated model and to require various types of data. The data needed for the model in this research are a few items such as purchased brands, consideration set, some benefits, and some demographic factors and easy to collect from consumers.

• Clinical and Experimental Pediatrics
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• v.50 no.6
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• pp.556-564
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• 2007

Purpose : We hypothesized that the persisting bronchial hyperresponsiveness (BHR) of adolescents with asthma remission may be controlled mainly by genetic factors, and the BHR of symptomatic asthma by airway inflammation. ${\beta}_2$-adrenoceptor gene is considered to be a candidate gene in the development of BHR. Thus, ${\beta}_2$-adrenoceptor gene polymorphism may be associated with the BHR of adolescents with asthma remission, but not with the BHR of symptomatic asthma. To evaluate this hypothesis, ${\beta}_2$-adrenoceptor gene polymorphism at 2 sites (Arg16-Gly, Gln27-Glu) were examined. Methods : Two hundred two adolescents with BHR ($PC_{20}<18\;mg/mL$) and long term remission (neither asthma-related symptoms nor medication during the previous 2 years) of their asthma (remission group), 182 adolescents with symptomatic asthma (symptomatic group), and 200 healthy adolescents (control group) were studied. Asthma phenotypes were determined using methacholine bronchial provocation test and skin prick test. Genotypes of ${\beta}_2$-adrenoceptor polymorphism were evaluated by PCR-based methods. Results : Gly/Gly allele and Gly16-Gln27 haplotype were more prevalent in the remission group than in the control group (P=0.01, P=0.02), although there was no difference between the symptomatic group and the control group. In the remission group, there was significant difference in geometric mean of $PC_{20}$ among the 3 groups subdivided by the number of Gly16-Gln27 haplotype, showing that the Gly16-Gln27 haplotype was positively associated with BHR. However, no association was found between Gly16-Gln27 haplotype and BHR in the symptomatic group. Conclusion : This study demonstrates that ${\beta}_2$-adrenoceptor polymorphism at amino acid 16 and 27 was associated with BHR persisting in adolescents with asthma remission.

• Journal of Chest Surgery
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• v.41 no.3
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• pp.354-359
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• 2008

Background: Warfarin is used as an anticoagulant and it is mainly excreted by the liver metabolism (the R-form is mainly metabolized by cytochrome p450 3A4, and the S form by cytochrome p450 2C9). Rifampin is usually used for tuberculosis or endocarditis, and it is a representative drug that induces the CYP families, including 3A4 and 2C9. The anticoagulation effect of warfarin decreases through the increased metabolism that's due to the induction of enzymes, and this iscaused by rifampin when patients take these two medicines together. No one has suggested appropriate guidelines regarding this drug interaction even though an appropriate adjustment of warfarin's dosage is needed. We examined the drug interaction in patients who received warfarin-rifampin combination therapy according to the time interval, and the factors affecting drug interaction were analyzed. Based on the data, we tried to determine the clinically available warfarin dosage guidelines before and after taking this drug combination. Material and Method: We reviewed the OO University Hospital anticoagulation service team's follow up sheets that were filled out from Jan '1998 to Sep 2006 for the patient who took warfarin - rifampin combination therapy (n=15). Result: The average INR of all the patient before rifampin administration was $2.25{\pm}0.52$ $(mean{\pm}SD)$, and that value for the first 100 days after rifampin administration was $1.98{\pm}0.28$. The p value for these two sets of data showed no correlation (paired t-test, p>0.05). The average INR of all the patient before rifampin cessation was $2.19{\pm}0.34$, and the value after rifampin cessation was $2.49{\pm}0.43$. The p value of these two showed correlation (paired t-test, p<0.05) but the average INR falls between the therapeutic INR range. Conclusion: The warfarin dose adjustment equation of before and after warfarin-rifampin combination therapy was derived based on this study's results because the warfarin dosage adjustment of the anticoagulation service team was considered appropriate.

• Korean Journal of Environmental Agriculture
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• v.24 no.1
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• pp.56-60
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• 2005

In order to increase the storage stability of watermelon stalk, storage environments such as temperature and other treatments such as vaseline, mixture of soybean oil and wheat flour, and coated paper label were tested separately after harvesting. At different storage temperatures (7, 18 and $30^{\circ}C$) shelf-life of stalk was inversely proportional to temperature. The results showed that during storage at $30^{\circ}C$ they were completely wilted in 7 days, at $18^{\circ}C$ in 15 days and at $7^{\circ}C$ in 19 days. Our data also showed that stability of watermelon stalk depending on temperature was very closely correlated with water content of watermelon stalk; during storage at $30^{\circ}C$ the water content of watermelon stalk was decreased to 21.1 % in 7 days, whereas at $7^{\circ}C$ the water content was decreased gradually to 71.2 % for 19 days of storage. In order to reduce the physiological changes in watermelon stalk at $30^{\circ}C$, following treatments such as vaseline, mixture of soybean oil and wheat flour, and coated paper label were tested. As a result, watermelon stalk without any treatment was completely wilted in 9 days, while stalks treated with vaseline and mixture of soybean oil with wheat flour were wilted in 15 and 12 days, respectively. The wilt delay was noted in the watermelon stalk for $3{\sim}6$ days during both treatments but the outward quality was found detracted, whereas when treated with coated paper label, the wilt of stalk was delayed for 3 days along with the improvement in the outward quality. Therefore this data indicate that the treatment of coated paper label during storage at $30^{\circ}C$ can be considered as a potent method for maintaining the physiology of watermelon stalk.

• Korean Journal of Environmental Agriculture
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• v.24 no.1
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• pp.1-5
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• 2005

Continuous monocropping of Chinese cabbage in Gangwon highland increased gravel and sand contents due to surface soil erosion. Nutrient leaching and Chinese cabbage growth were investigated with different treatments of gravel contents and nitrogen application levels by using $0.5m^2$ Wagner pots. Gravel contents were 0, 10, 30, 50, 70, and 90%(w/w), nitrogen application levels were 60, 120, and 240 kg/ha, and manure compost application rate was 15 ton per hectare, respectively. Wagner pots were filled with loamy sand soil mixed with 5 cm-sized gravels. Fresh weight of Chinese cabbage was decreased as gravel contents in soil increased, and particularly severely decreased at 240 kg-N/ha. Yields of Chinese cabbage were remarkably decreased at the rate of 60 kg-N/ha with 30% gravel content and 120 kg-N/ha with 50% gravel content. Most of Chinese cabbages were severely wilted by heavy N application at the rate of 240 kg-N/ha in the middle of growth stages regardless of gravel contents, while about 50% of Chinese cabbage showed wilting symptom in the treatment of more than 50% of gravel contents and 120 kg-N/ha. N content in leachate increased as gravel content and N application increased. The relationship between gravel content and N contents showed linear regression: N in leachate = 0.014(gravel content) -0.039 (r = 0.961). Particularly, $NH_4-N$ contents in leachates with more than 30% gravel content and 240 kg-N/ha ranged from $139{\sim}339mg/L$. Chinese cabbage growth in loamy sand soil containing 30%, and 50% gravel contents could be adversely affected by N application at the rate of 240, and 120 kg-N/ha, respectively.

• The Korean Journal of Petroleum Geology
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• v.5 no.1_2 s.6
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• pp.36-47
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• 1997

This study presents multi-variable sequence model for a broader application of sequence concept proposed by Exxon group. The concept of the multi-variable model is based on the fact that internal organization and boundary type of the sequences are determined by three varying factors including 3rd-order cycles of eustasy, and tectonic movement and sediment influx with 2nd-order changes. Instead of Exxon group's systems tracts, this model adopts parasequence sets as the fundamental building blocks of the sequence, because they are descriptive stratigraphic units simply defined by internal stacking pattern, reflecting interactions of accommodation and sediment influx. Seven sequence types which vary in number and type of internal parasequence sets are formulated as associations of four types of accommodation development and three grades of sediment influx. In the southwestern margin of Ulleung Basin, the multi-variable sequence analysis of shelf-slope sequence shows systematic changes in stratal patterns and the numbs, of constituent parasequence sets (i.e. sequence type). These changes are interpreted to reflect temporal and spatial changes in type and rate of tectonic movement and sediment influx, as a result of back-arc opening and closing. During the back-arc opening, rapid subsidence, continuous rise of relative sea level, and high sediment influx gave rise to sequences dominantly of single progradational parasequence set. In the early stage of back-arc closing accompanied by local contractional deformation, different types of sequences contemporaneously formed depending on the spatial changes in tectonically-controlled accommodation and influx rates. During the subsequent slow back-arc subsidence, rise-dominated relative sea-level cycle was coupled with moderate to high sedimentation rate to have resulted in sequences consisting of $2~3$ parasequence sets.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.153-154
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• 2003

운동여부와 운동횟수 그리고 어체 크기에 대한 양식산 어종의 품질판정을 위한 지표를 검색하기 위하여 효소적 방법 즉 ATP 관련화합물과 양식산 활어의 건강한 상태와 칼슘의 노출, 염도의 감소, 산소의 부족, 궁핍 등과 같은 스트레스를 받은 상태를 판단하는 adenylate energy charge (AEC)를 근육의 품질판정을 위한 지표로써 조사하였다. 운동사육구와 비운동사육구에서의 참돔육에 대한 ATP 관련화합물의 변화는 운동 0일에는 ATP함량은 8.62 μmol/g이었지만 20일차에는 8.59 μmol/g으로 운동기간이 길어짐에 따라 ATP의 함량은 약간의 감소를 보였다. 이는 운동이라는 자극요인으로 인하여 ATP의 소모가 촉진되었을 것으로 판단된다. 또한 운동 0일차의 ADP함량은 0.72 μmo1/g이었지만 20일차에는 0.93μmol/g로 ATP의 소모만큼 약간의 증가를 보이고 있다. 반면, 비운동사육구에서 0일차의 ATP함량은 5.78 μmol/g이었지만 20일차에서는 6.31 μmol/g로 운동사육구와 대조적으로 기간이 길어짐에 따라 ATP함량이 약간의 증가를 보여주고 있다. 생리적으로 동물에 가혹한 환경에 두거나 스트레스를 가하면 adenylate energy charge (AEC)가 영향을 받아 변화게 된다. AEC는 (ATP ＋ ½ ADP)/(ATP ＋ ADP + AMP)의 비율로 정의되는데, AEC의 범위는 0∼1사이로써 0은 ATP 관련화합물이 AMP로 전환된 상태를 말하며, 1은 모든 ATP 관련 화합물이 ATP로 존재하는 것을 의미한다. 그러므로, 이들결합의 상관적인 정도는 개개의 세포에서 에너지의 효용성을 측정하는 것으로 이용되고 있다. AEC 수치는 운동수조에서 0.91∼0.92 건강상태가 좋았지만 비운동수조는 0.87∼0.88로 운동수조에 비해 값이 낮게 나왔다. 운동횟수에 관계없이 운동시킨 어육의 AEC는 0.90∼0.91로 건강한 상태였다. 어체크기에 따른 ATP 관련화합물의 변화는 0.7∼0.9kg의 크기를 가진 참돔에서는 ATP 함량이 7.88 μmole/g, 1.5∼l,7kg의 크기를 가진 참돔에서는 ATP함량이 9.61μmole/g로 많았고 다른 크기에서는 큰 차이를 나타내지 않았다. 그리고 ADP함량은 어체의 크기가 증가할수록 함량은 감소하였다. 그러나, 어체의 크기에 따른 ATP관련화합물의 변화는 거의 없었다. 건강도의 지표인 AEC는 0.89∼0.94로 전체적으로 건강상태로 나타났다. 하루 2회 운동시킨 육에서의 ATP함량은 0일차에 8.75 μmole/g, 10일차에 8.46 μmole/g, 20일차에 8.51μmole/g로 약간의 감소를 보여준다. ADP함량은 일까지는 증가하지만 그 이후에는 큰 변화를 보이지 않는다. 6시간 운동시킨 그룹의 ATP함량은 0일차에 8.63 μmole/g, 5일차에 8.52 μmole/g, 10일차에 8.4μmole/g, 20일차에 8.51 μmole/g로 10일까지는 감소하지만 그 이후에는 큰 변화를 보이지 않는다. ADP함량은 0일차에 0.72 μmole/g, 10일차 0.84 μmole/g, 20일차에 0.83 μmole/g으로 10일차까지는 약간 증가하지만 그 이후에는 큰 변화를 보이지 않았다. 참돔의 근원섬유에 있어서 Ca/sup 2+/이 존재할 때 Mg/sup 2+/-ATPase 활성의 변화는 운동시킨 참돔 근원섬유의 Mg/sup 2+/-ATPase 활성은 0.35μmol Pi/minㆍmg였으며, 비운동구에서 0.34μmol Pi/minㆍmg으로 운동시킨 참돔의 육에서 ATPase 활성이 약간 높은 것으로 나타났다. 운동사육시킨 참돔은 운동기간이 증가할수록 ATPase활성이 증가하여 운동 20일에는 0.42μmo1 Pi/minㆍmg의 함량을 나타내었으나, 비운동사육에서는 큰 차이를 보이지 않고 있다. 근원섬유의 Ca/sup 2+/가 첨가되지 않았을때의 Mg/sup 2+/-ATPase 활성을 나타내었다. 운동시키전에는 각각 0.10μmol Pi/minㆍmg, 0.14μmol Pi/minㆍmg 나타나 비운동구가 운동구에 비하여 Mg/sup 2+/(-Ca/sup 2+/)-ATPase 활성이 높았으며 사육기간동안 활성이 서서히 감소하는 경향을 나타내었다. Ca/sup 2+/-ATPase의 활성 또한 사육기간 동안 큰 변화를 보이지 않았다. 그러므로, 참돔의 운동여부에 따라서 ATPase활성을 살펴본 결과, 운동기간에 따른 약간의 차이는 보이고 있으나, 품질지표로써 사용하기가 어렵다고 판단된다. 효소적인 방법을 이용한 양식산 활어의 품질지표로써 ATP 관련화합물, ATPase 활성은 운동여부, 크기에 따라 객관적인 지표로써의 사용이 어려우므로, 건강도를 측정할 수 있는 AEC의 수치를 적용하는 것이 적합하다고 판단된다. 즉, 양식산 참돔의 AEC 수치가 1∼0.9의 범위에서는 건강한 활어로 상급의 등급을, 0.8∼0.7의 AEC 수치는 중급의 등급으로, 그 이하의 수치에서는 하급으로 적용가능 하다고 판단된다.

• Korean Journal of Ecology and Environment
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• v.34 no.1 s.93
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• pp.9-19
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• 2001

contrasting monsoon between 1993 and 1994 produced an interannual difference in hydrology. Theoretical water residence time (TWRT) in monsoon 1993 averaged 27 d, which was>3 months shorter compared to the TWRT in monsoon 1994. A dominant physical process influencing thermal stratification, water movement, and mixing regime was an interflow current in 1993. During summer 1993, river water plunged to mid-lake (location 27 km) and passed through the 10${\sim}$20m stratum of the reservoir, resulting in an isolation of epilimnetic lake water from advected river water. The interflow disrupted thermal stratification and produced a meta-hypolimnetic warming of >4$^{\circ}C$ downlake, thereby increased a mixing depth (>13 m). In contrast, during monsoon 1994 density currents were not observed and strong thermal stratification occurred in the entire reservoir, resulting in > 2 fold greater thermal resistance (8.2${\times}10^{5}$ erg)compared to 1993 (4.0${\times}10^{5}$ erg). This reservoir was identified as a typical warm monomictic reservoir which showed one mixis during early winter. The timing of overturn, however, differed between the two years as a result of distinct contrast in TWRT and thermal regime; overturn in 1993 occured about one month earlier relative to that in 1994. Hypolimnetic warming was predictable in this system; the variation in discharge accounted (Y = 4.35-0.06X+0.10X$^{2}$, p<0.0001)for 98% of the interannual variation in hypolimnetic temperature. Overall data suggest that thermal stability, the timing of fall overturn, and water residence time in this system are primarily regulated by the intensity of monsoon.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.451-458
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• 2012

This study was conducted to investigate the characteristic factors which have been influenced on nitrous oxide ($N_2O$) emissions related to the environment change of nitrogen application level, rainfall and temperature during the soybean cultivation at black volcanic ash soil from 2010 to 2011. During the soybean cultivation, the more amount of nitrogen fertilizer applied, $N_2O$ emissions amounts were released much. $N_2O$ emissions with the cultivation time were released much at the first and middle of cultivation with heavy rainfall, but it was released very low until the end of cultivation and drought season. $N_2O$ emissions mainly were influenced by the rainfall and soil water content. The correlation ($r$) with $N_2O$ emissions, soil water, soil temperature and soil EC in 2010 were very significant at $0.4591^{**}$, $0.6312^{**}$ and $0.3691^{**}$ respectively. In 2011, soil water was very significant at $0.4821^{**}$, but soil temperature and soil EC were not significant at 0.1646 and 0.1543 respectively. Also, $NO_3$-N and soil nitrogen ($NO_3-N+NO_4-N$) were very significant at $0.6902^{**}$ and $0.6277^*$ respectively, but $NO_4$-N was not significant at 0.1775. During the soybean cultivation, the average emissions factor of 2 years released by the nitrogen fertilizer application was presumed to be 0.0202 ($N_2O$-N kg $N^{-1}\;kg^{-1}$). This factor was higher about 2.8 and 2 times than the Japan's (0.0073 $N_2O$-N kg $N^{-1}\;kg^{-1}$) value and 2006 IPCC guideline default value (0.0100 $N_2O$-N kg $N^{-1}\;kg^{-1}$) respectively.

• Economic and Environmental Geology
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• v.45 no.3
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• pp.277-294
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• 2012

The characteristics of temporal spacial radon variation in soil according to parent rock type and affecting factors were studied in Busan, Korea. The concentration of $^{222}Rn$ in soils and their parent elements ($^{226}Ra$,$^{228}Ra$, U and Th) in rocks and soils were measured at 24 sites in Busan area. The distribution and transportation behavior of these parent elements were analyzed and their correlations to radon concentration in soil were determined. Topographic effects were also evaluated. Two in-situ radon measurement (soil probe and buried tube) methods were applied to measure radon concentration in soil and their accuracies were evaluated. The spatial variation of radon in soil generally reflected U concentration in the parent rock. Average radon concentrations were higher in plutonic rocks than in volcanic rocks and were decreased in the order of felsic>intermediate>mafic rock. However, the radon concentrations were significantly varied in soils developed from same parent rocks due to the disequilibrium of U and $^{226}Ra$ between rock and soil. As results, the correlation of these element concentrations between rocks and soils was very low and radon concentrations in soils had highly co-related to the concentrations of these elements in soils. Th and $^{228}Ra$ show complex enrichment characteristics, differing significantly with U, in soils developed from same parent rock because the geochemical behavior of these elements during weathering and soil developing process was different with U. The radon concentrations in the same depth of soil in slope area were also different according to positions. The radon concentrations in soils developed from same parent rocks (19 sites at Pusan National University) varied 6.8~29.8Bq/L range because of small scale topographic variation. The opposite seasonal variation pattern of radon were observed according to soil properties. It was determined that buried tube method is more accurate method than soil probe method and was very advantageous application for the analysis for the characteristics of temporal spacial radon variation in soil.