• KOREAN JOURNAL OF CROP SCIENCE
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• v.3
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• pp.41-48
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• 1965

This study was aimed at knowing the magnitude of year variation in rice heading dates under the different seasonal cultures, and to estimate the heading date in advance. Using six rice varieties such as Kwansan, Suwon＃82, Suwon ＃144, Norin＃17, Yukoo＃132 and Paltal, the early, ordinary and late seasonal cultures had been carried out at Paddy Crop Division, Crop Experiment Station at Suwon for the six-year period 1959 to 1964. In addition the data of the standard rice cultures at the Provincial Offices of Rural Development for the 12-year period 1953 to 1954, were analyzed for the purpose of clarifying a relationship between variation of rice heading dates and some of meteorological data related to the locations and years. The results of this study are as follows: 1. Year variation of rice heading dates was as high as 14 to 21 days in the early seasonal culture and 7 to 14 days in the ordinary seasonal culture, while as low as one to seven days in the late seasonal culture which was the lowest among three cultures. The magnitude of variation depended greatly on variety, cultural season and location. 2. It was found out that there was a close negative correlation between the accumulated average air temperature for 40 days from 31 days after seeding and number of days to heading in the early seasonal culture. Accordingly, it was considered possible to predict the rice heading date through calculation of the accumulated average air temperature for the above period and then the linear regression(Y=a+bx). On the other hand, an estimation of the heading date in the late seasonal culture requires for the further studies. In the ordinary seasonal culture, no significant correlation between the accumulated average air temperature and number of days to heading was obtained in the six-year experiments conducted at Suwon. There was a varietal difference in relationship between the accumulated average air temperature for 70 days from seeding and number of days to heading in the standard cultures at the provincial offices of rural development. Some of varieties showed a significant correlation between two factors while the others didn't show any significant correlation. However, there was no regional difference in this relationship.

• Journal of the Korean association of regional geographers
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• v.23 no.1
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• pp.151-167
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• 2017

The main objective of this study was to investigate the climatic impact of $PM_{10}$ concentration on the temperature change pattern in Busan Metropolitan City(BMC), Korea during 2001~2015. Mean $PM_{10}$ concentration of BMC has gradually declined over the past 15 years. While the highest $PM_{10}$ concentration was observed in spring followed by winter, summer, and fall on average, the seasonal variations of $PM_{10}$ concentration differed from place to place within the city. Frequency analysis showed that the most frequently observed $PM_{10}$ concentration ranged from $20{\mu}g/m^3$ to $60{\mu}g/m^3$, which accounted for 64.6% of all daily observations. Overall, the west-high and east-low pattern of $PM_{10}$ concentration was relatively strong during the winter when the effect of yellow-dust events on the air quality was weak. Comparative analyses between $PM_{10}$ concentration and monthly temperature slope derived from generalized temperature curves indicated that the decreasing trend of $PM_{10}$ concentration was associated with increases of annual temperature range, and $PM_{10}$ concentration had a negative relationship with the temperature slope of warming months. Overall, $PM_{10}$ concentration had a weak correlation with the annual mean temperature, but it had a significant, positive correlation with the winter season, which had a dominant influence on the annual mean temperature. In terms of energy budget, it has been known that the change in $PM_{10}$ concentration contributes to the warming or cooling effect by affecting the radiative forcing due to the reflection and absorption of radiant energy. The correlation between $PM_{10}$ concentration and temperature changes in the study area was not seasonally and spatially consistent, and its significance was statistically limited partly due to the number of observations and the lack of potential socioeconomic factors relevant to urban air quality.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.707-718
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• 2019

Ecklonia cava Kjellman, which has recently gained popularity due to the spread of farming techniques, is expected to be developed in various varieties in the future. There exist increased needs for research on the basis of natural populations and inter-regional morphological variations. We compared the morphology of the aquaculture and natural populations from 16 coastal areas in Korea. The 18 traits found suitable for distinguishing varieties were selected from 14 measurement traits and 4 ratios related to the main morphology and characteristics of primary blade, secondary blade, and stipe. In the cluster analysis, Janggil (E4) and Sorok (S7) showed significant differences from those of the same coastal region. Two groups, including Suyou (Q6, Q8, and Q10) which was the second year of farming, of the rest of the populations from East sea and southern coast were distinguished. Three populations of Jeju were divided into a regional group. In the principal component analysis (PCA), a large number of populations from East sea and Southern coast appeared in the center with aquaculture populations. PC1 and PC2 associated with traits of secondary blade index, stipe length and diameter, stipe length/primary blade length, primary blade length and width, secondary blade number, secondary blade length and width, divided E4, S7 and populations of Jeju region. As a result, the 18 characters of this study were found to be useful as criteria for discrimination of populations with significant differences in each coastal region, and these populations were expected to be candidates for new varieties.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.509-519
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• 2000

Enlow's counterpart analysis explains the complex with anatomic and developmental characteristics where craniofacial aspect of individuals has been developed. The analysis does not compare individual measurement with the normal value from the average of majority but analyzes by comparison of values that each individual has. This study was to clarify the Korean craniofacial skeletal pattern using Enlow's counterpart analysis considering the fact that the craniofacial skeletal pattern has racial and regional variations. This research will be helpful in the future for growth research and research of the orthognathic surgery. For this study, the samples were consisted of 100 Korean adult subjects(50 males and 50 females) who had normal occlusion and pleasing face. Measurement points and lines were established using Enlow's counterpart analysis and they were statistically evaluated. The results indicated that : 1. The average angle between PCF and PMV was $38.54^{\circ}$ in males and $38.43^{\circ}$ in females, and the average Wits' appraisal was -2.51 in males and -2.3 in females. The ramus alignment(R4) was 1.89 in males and 2.36 in females. 2. It shows that females have a longer ramus than the PCF compared to the males, because there was a significant difference in Ramus/PCF horizontal dimensions (Skeletal A3-B3) between female and male subjects 3. It shows that males have a longer mandibular corpus than the maxilla compared to the females, because there was a significant difference in Maxillary/Mandibular arches(Skeletal A4-B4) between male and female subjects 4. In cranial floor+maxilla/ramus+corpus at A and B points(Al-Bl), which represents difference in total horizontal length between the maxilla and mandible, there was no significant difference between males and females. In conclusions, compared to Caucasian, Korean have more depressed midface, prognathic mandible, and ramus that rotates inferioposterior. Also, we observe that Korean women have target ramus posterior cranial base, as compared with Korean men. Consequently, the total length of maxilla and mandible does not show any difference, because man's mandible is longer than maxilla in comparison with woman's one.

• Korean Journal of Ichthyology
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• v.13 no.2
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• pp.143-157
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• 2001

To determine seasonal fluctuations in abundance and species composition of the fishes, samples were collected by bottom trawl off Kohung Penisula from February to December 1999. A total of 7,197 fishes were sampled and identified into 123 species, 54 families, 13 orders and 2 classes. Of the 13 orders, Perciformes, Scorpaniformes, Pleuronectiformes and Tetraodontiformes accounted for approximately 82.9% of the total. Gobiid fishes were dominant, representing 13 species. Leiognathus nuchalis, Konosirus punctatus, Engraulis japonicus, Ilisha elongata, Trichiurus japonicus, Argyrosomus argentatus, Ditrema temmincki, Takifugu niphobles, Hexagrammos otakii and Lateolabrax japonicus accounted for 71.4% of the number of individuals. Mugil cephalus, Sebastes schlegeli, Lateolabrax japonicus, Konosirus punctatus, Hexagrammos otakii, Conger myriaster, Liparis tanakai, Seriola quinqueradiata, Trichiurus japonicus, Sebastiscus marmoratus and Limanda yokohamae accounted for 50.7% of the total biomass. The number of species showed a seasonal variation, higher in spring, summer and autumn than in winter. The Largest numbers of individuals and greater biomass were observed in August. The economic fishes of this area were Konosirus punctatus, Engraulis japonicus, Mugil cephalus, Sebastes inermis, Sebastes schlegeli, Sebastes oblongus, Sebastiscus marmoratus, Platycephalus indicus, Hexagrammos agrammus, Hexagrammos otakii, Lateolabrax japonicus, Epinephelus akaara, Epinephelus septemfasciatus, Seriola quinqueradiata, Pagrus major, Acanthopagrus schlegeli, Argyrosomus argentatus, Oplegnathus fasciatus, Trichiurus japonicus, Pampus echinogaster, Paralichthys olivaceus, Kareius bicoloratus, Limanda yokohamae and Takifugu porphyreus.

• Economic and Environmental Geology
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• v.52 no.6
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• pp.541-554
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• 2019

The Taebaeksan Zone of the Okcheon Belt is a prominent fold-thrust belt, preserving evidence for overlapped polyphase and diachronous orogenic events during crustal evolution of the Korean Peninsula. The Pyeongchang-Jeongseon area of the northwestern Taebaeksan Zone is fault-bounded on the western Jucheon and southern Yeongwol areas, showing lateral variations in stratigraphy and structural geometries. For better understanding these geological characteristics of the northwestern Taebaeksan Zone, we have studied the structural geometry of the Pyeongchang-Jeongseon area. For this, we have firstly carried out the SHRIMP U-Pb age analysis of the age-unknown sedimentary rock to clarify stratigraphy for structural interpretation. The results show the late Carboniferous to middle Permian dates, indicating that it is correlated to the Upper Paleozoic Pyeongan Supergroup. In addition to this, we interpreted the geometric relationships between structural elements from the detailed field investigation of the study area. The major structure of the northwestern Taebaeksan Zone is the regional-scale Jeongseon Great syncline, having NE-trending hinge with second-order folds such as the Jidongri and Imhari anticlines and the Nambyeongsan syncline. Based on the stereographic and down-plunge projections of the structureal elements, the structural geometry of the Jeongseon Great syncline can be interpreted as a synformal culmination, plunging slightly to the south at its southern area, and north at the northern area. The different map patterns of the northern and southern parts of the study area should be resulted in different erosion levels caused by the plunging hinges. Considering the Jeongseon Great syncline is the major structure that constrains the distribution of the Paleozoic strata of the Pyeongchang and Jeongseon areas, the symmetric repetition of the lower Paleozoic Joseon Supergroup in both limbs should be re-examined by structural mapping of the Hangmae and Hoedongri formations in the Pyeongchang and Jeongseon areas.

• Korean Journal of Ecology and Environment
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• v.39 no.3 s.117
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• pp.320-330
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• 2006

An integrated health of a lotic ecosystem, Cho River, was evaluated by various approaches such as conventional water quality analysis, physical assessments of Qualitative Habitat Evaluation Index (QHEI), and the bioassay of Index of Biological Integrity (IBI) durin August${\sim}$September 2005. The IBI model used in the study was based on original multivariate metric model and then modified the metric attributes of the model for the regional application. Physical habitat health, based on the QHEI, was estimated using eleven metrics. During the study, values of IBI model averaged 36, which was judged as 'fair' to 'good' conditions. Spatial variations in the model values were evident: the headwater site (S1) was estimated as 48, indicating an 'excellent' condition, and the other sites were estimated 32${\sim}$38, 'good' condition. Values of the QHEI in the all sites averaged 148, which is judged as a good condition. The QHEI values varied from 120 (fair condition) to 199 (excellent condition) depending on the location of the stream. Site 5 (S5) was estimated as 'fair${\sim}$good' condition, while Site 7 (S7) was estimated as 'excellent' condition. The biological health, based on the IBI, reflected the habitat health. However, chemical conditions in terms of pH, turbidity, electric conductivity, dissolved oxygen (DO) did not make a difference in the biological health because of minor chemical differences among the locations.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.361-371
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• 2005

The objective of study was to diagnose integrative ecological health of Daejeon Stream, one of the tributaries of Guem River, during May 2004 ${\sim}$ April 2005. The research approach was primarily based on a Qualitative Habitat Evaluation Index (QHEI) and the Index of Biological Integrity (IBI) using fish assemblage. These outcomes were compared with conventional chemical dataset. For the experiment, four sampling sites were chosen from Daejeon Stream and long-term water quality data during 1995 ${\sim}$ 2004 (obtained from the Ministry of Environment) were analyzed in the spatial and temporal aspects. For the biological health assessment, we developed a stream health assessment model (SHA model) far regional applications. We found that current water quality conditions, based on the COD, BOD, TN and TP, were enhanced by 1.6 ${\sim}$ 5.3 fold over the period of 1995 ${\sim}$ 2004 and that the parameters showed a typical longitudinal decline from the upstream to downstream reach. The differences of water quality between the two reaches were more than 4.4 times, indicating a large spatial variations within the stream. The health conditions, based on the SHA model, averaged 23 and varied from 20 to 26 depending on the sampling stations. Values of the QHEI varied from 39 (Poor condition) to 124 (Cood condition)and values of QHEI in the reach of S2 ${\sim}$ S4 had significantly lower than in the headwater site (S1). Also, biological stream health, based on the criteria of US EPA (1993), was judged as 'Poor condition', in the S4 where TN, TP, BOD and COD were highest. In the meantime, maximum value of SHA (26) was found in the upstream reach (S1) where the water quality and QHEI were best. We also found that compositions of sensitive species showed a linear function with water quality conditions and this pattern was evident in the tolerant species. Thus, the biological stream health, based on the SHA model, matched well water chemistry. Overall outcomes suggest that the biological health impact was a function of chemical degradation and physical habitat quality in the stream.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.3
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• pp.214-219
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• 2010

In order to evaluate the benefits of global warming on the double cropping with staple crops in North-Korea, four aspects such as the increasing rate of air temperature, the wintering temperatures for winter crops, the causing temperature of cool injury to rice and the securing of accumulated temperature for the double cropping in the different agricultural climate zones were analyzed by comparing the differences between the past 22 years from 1973 to 1994 and the recent 5 years from 2002 to 2006. The warming rate in recent daily mean air temperature of $8.96^{\circ}C$ in North Korea was higher by $0.64^{\circ}C$ than that in the past with large regional variations ranging from $1.06^{\circ}C$ in Samjiyeon of northern inland semi-alpine zone to $12.26^{\circ}C$ in Jangjeon of east central coastal zone. With the accumulated temperatures of more than $3,150^{\circ}C$ and $2,650^{\circ}C$, it was possible to apply the double cropping patterns with winter wheat and for cropping patterns with spring potato, respectively, to the whole region except for the northern inland semi-alpine zone. However, the wintering temperature higher than $-15^{\circ}C$ of average daily minimum air temperature of January, cropping patterns were impossible to northern inland semi-alpine zone and most regions of the northern mountainous zone. The days passed by below $17^{\circ}C$ in daily mean air temperature, causing the spikelet sterility at meiotic stage of rice in July, were a lot recorded from 21 to 29 days in northern inland semi-alpine zone and from 2 to 10 days in east-northern coastal zone, respectively. Therefore, a reasonable utilization of heat / temperature resources would relieve the limiting factors in double cropping for stable production of staple crops in North-Korea.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.145-156
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• 2006

The objective of this study was to evaluate biological health conditions and physicochemical status using multi-metric models at five sites of the Keum-Ho River during August 2004 and June 2005. The research approach was based on a qualitative habitat evaluation index (QHEI), index of biological integrity (IBI) using fish assemblage, and long-term chemical data (1995 ${\sim}$ 2004), which was obtained from the Ministry of Environment, Korea. For the biological health assessments, regional model of the IBI in Korea (An,2003), was applied for this study. Mean IBI in the river was 30 and varied from 23 to 48 depending on the sampling sites. The river health was judged to be "fair condition", according to the stream health criteria of US EPA (1993) and Barbour et al. (1999). According to the analysis of the chemical water quality data of the river, BOD, COD, conductivity, TP, TN, and TSS largely varied epending on the sampling sites, seasons and years. Variabilities of some parameters including BOD, COD, TP, TN, and conductivity were greater in the downstream than in the upstream reach. This phenomenon was evident in the dilution by the rain during the monsoon. This indicates that precipitation is a very important factor of the chemical variations of water quality. Community analyses showed that species diversity index was highest (H=0.78) in the site 1, while community dominance index was highest in the site 3, where Opsariichthys uncirostris largely dominated. In contrast, the proportions of omnivore and tolerant species were greater in the downstream reach, than in the upstream reach. Overall, this study suggests that some sites in the downstream reach may need to restore the aquatic ecosystem for better biological health.