• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.67-74
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• 2021

Domestically, technical condition evaluation for breakwaters has been conducted through safety checks and safety diagnosis. If necessary, maintenance for the facility is conducted. However, in recent years, the need for infrastructure management has been increasing from a life-cycle-cost perspective. For these reasons, the "Sustainable Infrastructure Management Basic Act" was enacted. Previously, only the technical part of the breakwaters was evaluated. However, based on the act, comprehensive management of breakwaters will be possible through performance improvement by adding economic and political evaluations. In this study, evaluation factors and evaluation methods were developed for a breakwater rehabilitation project. The purpose of this study is to present a development direction, items, and methods for the evaluation of breakwater performance improvement to be applied in future practice. This study reviews the concept of maintenance and performance improvement, the literature related to performance improvement, and the project type for the common standard of performance improvement. Evaluation items and evaluation methods for breakwater rehabilitation are suggested to be reviewed by experts. The methodology suggested in this study could be used for preventive maintenance and to reduce accidents.

• Communications of Mathematical Education
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• v.37 no.3
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• pp.393-417
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• 2023

The necessity of this study was to improve academic achievement and math attitudes through leveled reciprocal peer learning, and the specific purpose was as follows. First, each unit seeks to select learning methods and contents for each level of class for reciprocal peer learning, second, develop activity sites for each level through curriculum analysis, and third, improve academic achievement and math attitudes through classes that apply reciprocal peer learning activities. The study was conducted on 60 second graders of 00 High School in 00 Metropolitan City. Two classes were selected for the midterm exam results for the first semester of the second grade. Class 1 was divided into the experimental group and the other class 1 was divided into the comparative group, and 13 classes were conducted for about 2 months from May 1 to July 4, 2020. The experimental group (30 students) was a class that applied leveled reciprocal peer learning activities, and the comparative group (30 students) was a class that was taught based on traditional textbooks. As a result of this study, first, in this study, it was possible to improve academic achievement and math attitudes by setting learning contents for each unit and applying reciprocal peer learning activities for each level. Second, the experimental group taught by applying leveled reciprocal peer learning activities was effective in academic achievement and math attitudes compared to the comparative group taught based on traditional textbooks to students in the upper, middle, and lower groups. Third, in the class applying leveled reciprocal peer learning activities, low-level students who were neglected in math classes were also interested in the class and actively participated in it, showing improvement.

• Korean Journal of Ecology and Environment
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• v.38 no.1 s.110
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• pp.54-62
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• 2005

The present study was to determine how seasonal rainfall intensity influences nutrient dynamics, ionic contents, oxygen demands, and suspended solids in a lotic ecosystem. Largest seasonal variabilities in most parameters occurred during the two months of July to August and these were closely associated with large spate of rainfall. Dissolved oxygen (DO) had an inverse function of water temperature (r = = = - 0.986, p<0.001). Minimum pH values of<6.5 were observed in the late August when rainfall peaked in the study site, indicating an ionic dilution of stream water by precipitation. Electrical conductivity (EC) was greater during summer than any other seasons, so the overall conductivity values had direct correlation (r = 0.527, p<0.01) with precipitation. Ionic dilution, however, was evident 4 ${\sim}$ 5 days later in short or 1 ${\sim}$ 2 weeks in long after the intense rain, indicating a time-lag phenomenon of conductivity. Daily COD values varied from 0.8 mg $L^{-1}$ to 7.9 mg $L^{-1}$ and their seasonal pattern was similar (r = 0.548, p<0.001) to that of BOD. Total nitrogen (TN) varied little compared to total phosphorus (TP) and was minimum in the base flow of March. In contrast, major input of TP occurred during the period of summer monsoon and this pattern was similar to suspended solids, implying that TP is closely associated (r = 0.890, p<0.01) with suspended inorganic solids. Mass ratios of TN : TP were determined by TP (r= -0.509, p<0.01) rather than TN (r= -0.209, p<0.01). The N : P ratios indicated that phosphorus was a potential primary limiting nutrient for the stream productivity. Overall data suggest that rainfall intensity was considered as a primary key component regulating water chemistry in the stream and maximum variation in water quality was attributed to the largest runoff spate during the summer monsoon.

• Journal of Korean Medical Ki-Gong Academy
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• v.4 no.2
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• pp.153-186
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• 2000

Jigam(止感), Josik(調息), Kumchock(禁觸), from the lecture on Truth of ${\ll}Samilshingo{\gg}$(三一神誥) treat three elements of Kigong, regulation of mental activties, regulation of breathing and adjustment of posture and there are some similar mentions with the view of human body based on oriental medicine like those Samjin(三眞), Sammang(三妄), Samdo(三途) and Sippalkyoung(十八境) ect. Thus as a result of comparison and observation about the interrelationships between principle of Kigong in the lecture on Truth of ${\ll}Samilshingo{\gg}$(三一神誥) and oriental medicine. I have conclusion as follows. 1. According to the lecture on Truth, the components of human body are the one and only Samjin(三眞), Sammang(三妄) and Samdo(三途) resulted from facing Samjin(三眞) to Sammang(三妄) and Sippalkyoung(十八境). This fact presents the principle of human change. 2. the principle of Kigong mentioned in the lecture on Truth shows the original Ilshin(一神) on the basis of Samjin(三眞), Sammang(三妄), Samdo(三途) and Sippalkyoung(十八境). This makes common, unity and sound Sim(心), Ki(氣) and Shin(身), Sammang(三妄) through Jigam(止感), Josik(調息) and Kumchock(禁觸), be versed, intellected and guaranteed Sung(性), Myoung(命) and Jung(精), Samjin(三眞) and emit Kyun(見), Mun(聞), Ji(知) and haeng(行), Sadaeshingi(四大神機) and finally all these are harmonized into Duk(德), Hye(慧) and Ryuk(力), Samdae(三大) which is the entity of God. 3. Samsipyookjongmyowhasang(三十六種妙化相) is an ascetic practice done after a chulin(哲人) deduce Ji(止), Jo(調) and Kum(禁), Sambup(三法) on the basis of the lecture on Truth. So I suppose it correlates nature's six elements. Kong(空)(Chun(天)). Yol(熱)(Wha(火)). Jin(震(Jeon(電)), Seup(濕)(Shoo(水)), Han(寒)(Poong(風)) and Ko(固)(Ji(地)), human's Samjin(三眞), Sung(性), Myoung(命) and Jung(精) and Sammang(三妄), Sim(心), Ki(氣) and Shin(身) and makes clear the principle of discipline. 4. In comparison with Samjin(三眞) and Sammang(三妄) says from the lecture on Truth and the Three Essential Elements of the body construction(三寶) from oriental medicine, Samjin(三眞) and Sammang(三妄) as factors of human body in the concept of practical knowledge. That is the one and only Samjin(三眞) in terms of the Three Essential Elements of the body construction(三寶) is considered a structural principle for every single person and Sammang(三妄) is considered a functional form for each individual. And it can be Sung(性)+Sim(心)=Spirit(神), Myoung(命)+Ki(氣)=Vital Force(氣) and Jung(精)+Shin(身)=True Essence(精). 5. In comparison with Sippalkyoung(十八境) of Samdo(三途) from the lecture on Truth and three medical causes of disease, Gamdoyookkyoung(感途六境) is similar with endopathic cause caused by Naesangchiljung(內傷七情), Sikdoyukkyoung(息途六境) is similar with exopathic cause by six climatic conditions in excess as pathogenic factors(六淫) and Yoegi(?氣) and Chokdoyukkyoung(觸途六境) is similar with non-endo-exopathogenic causes by diet imbalance, fatigue, intemperance in sexual life and trauma etc. 6. In the lecture on Truth, the Chulin(哲人) who discipline Sambup(三法), Sangchul(上哲), Choongchul(中哲) and Hachul(下哲) can be compared with Kigong expert(health preserving expert) such as the Spiritual Men(眞人), the Sapients(至人), the Sages(聖人) and the Men of Exellent Virtue(寶人) in the Sang Gu Tian Zhen Lun of the Huang Ti Nei Ching Su Wen(素問 上古天眞論) and then Sangchul(上哲) is the Spiritual Men(眞人), Choongchul(中哲) is the Sapients(至人) and Hachul(下哲) is the Sages(聖人) while the men of Exellent Virtue(賢人) is inferior to Chulin(哲人) when he goes to extremes.

• Economic and Environmental Geology
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• v.44 no.6
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• pp.463-474
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• 2011

The Haenam epithermal mineralized zone is located in the southwestern part of South Korea, and hosts low sulfidation epithermal Au-Ag deposit (Eunsan-Moisan) and clay quarries (Okmaesan, Seongsan, and Chunsan). Epithermal deposits and accompanying hydrothermal alteration related to Cretaceous volcanism caused large zoned assemblages of hydrothermal alteration minerals. Advanced argillic-altered rocks with mineral assemblages of alunite-quartz, alunite-dickite-quartz, and dickite-kaolinite-quartz exposed on the Okmaesan, Seongsan, and Chunsan area. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), with three visible and near infrared bands, six shortwave infrared bands, and five thermal infrared bands, was used to identify advanced argillic-altered rocks within the Haenam epithermal mineralized zone. The distinct spectral features of hydrothermal minerals allow discrimination of advanced argillic-altered rocks from non-altered rocks within the study area. Because alunite, dickite, and kaolinite, consisting of advanced argillic-altered rocks within the study area are characterized by Al-O-H-bearing minerals, these acid hydrothermal minerals have a strong absorption feature at $2.20{\mu}m$. The band combination and band ratio transformation cause increasing differences of DN values between advanced argillic-altered rock and non-altered rock. The alunite and dickite-kaolinite of advanced argillic-altered rocks from the Okmaesan, Seongsan, and Chunsan have average DN values of 1.523 and 1.737, respectively. These values are much higher than those (1.211 and 1.308, respectively) of non-altered area. ASTER images can remotely provide the distribution of hydrothermal minerals on the surface. In this way good relation between ASTER spectra analysis and field data suggests that ASTER spectral analysis can be useful tool in the initial steps of mineral exploration.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.9 no.1
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• pp.1-18
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• 1973

For regulating the depth of midwater trawl nets towed at the optimum constant speed, the changes in the shape of warps caused by adding a weight on an arbitrary point of the warp of catenary shape is studied. The shape of a warp may be approximated by a catenary. The resultant inferences under this assumption were experimented. Accordingly feasibilities for the application of the result of this study to the midwater trawl nets were also discussed. A series of experiments for basic midwater trawl gear models in water tank and a couple of experiments of a commercial scale gears at sea which involve the properly designed depth control devices having a variable attitude horizontal wing were carried out. The results are summarized as follows: 1. According to the dimension analysis the depth y of a midwater trawl net is introduced by $$y=kLf(\frac{W_r}{R_r},\;\frac{W_o}{R_o},\;\frac{W_n}{R_n})$$) where k is a constant, L the warp length, f the function, and $W_r,\;W_o$ and $W_n$ the apparent weights of warp, otter board and the net, respectively, 2. When a boat is towing a body of apparent weight $W_n$ and its drag $D_n$ by means of a warp whose length L and apparent weight $W_r$ per unit length, the depth y of the body is given by the following equation, provided that the shape of a warp is a catenary and drag of the warp is neglected in comparison with the drag of the body: $$y=\frac{1}{W_r}\{\sqrt{{D_n^2}+{(W_n+W_rL)^2}}-\sqrt{{D_n^2+W_n}^2\}$$ 3. The changes ${\Delta}y$ of the depth of the midwater trawl net caused by changing the warp length or adding a weight ${\Delta}W_n$_n to the net, are given by the following equations: $${\Delta}y{\approx}\frac{W_n+W_{r}L}{\sqrt{D_n^2+(W_n+W_{r}L)^2}}{\Delta}L$$ $${\Delta}y{\approx}\frac{1}{W_r}\{\frac{W_n+W_rL}{\sqrt{D_n^2+(W_n+W_{r}L)^2}}-{\frac{W_n}{\sqrt{D_n^2+W_n^2}}\}{\Delta}W_n$$ 4. A change ${\Delta}y$ of the depth of the midwater trawl net by adding a weight $W_s$ to an arbitrary point of the warp takes an equation of the form $${\Delta}y=\frac{1}{W_r}\{(T_{ur}'-T_{ur})-T_u'-T_u)\}$$ Where $$T_{ur}^l=\sqrt{T_u^2+(W_s+W_{r}L)^2+2T_u(W_s+W_{r}L)sin{\theta}_u$$ $$T_{ur}=\sqrt{T_u^2+(W_{r}L)^2+2T_uW_{r}L\;sin{\theta}_u$$ $$T_{u}^l=\sqrt{T_u^2+W_s^2+2T_uW_{s}\;sin{\theta}_u$$ and $T_u$ represents the tension at the point on the warp, ${\theta}_u$ the angle between the direction of $T_u$ and horizontal axis, $T_u^2$ the tension at that point when a weights $W_s$ adds to the point where $T_u$ is acted on. 5. If otter boards were constructed lighter and adequate weights were added at their bottom to stabilize them, even they were the same shapes as those of bottom trawls, they were definitely applicable to the midwater trawl gears as the result of the experiments. 6. As the results of water tank tests the relationship between net height of H cm velocity of v m/sec, and that between hydrodynamic resistance of R kg and the velocity of a model net as shown in figure 6 are respectively given by $$H=8+\frac{10}{0.4+v}$$ $$R=3+9v^2$$ 7. It was found that the cross-wing type depth control devices were more stable in operation than that of the H-wing type as the results of the experiments at sea. 8. The hydrodynamic resistance of the net gear in midwater trawling is so large, and regarded as nearly the drag, that sweeping depth of the gear was very stable in spite of types of the depth control devices. 9. An area of the horizontal wing of the H-wing type depth control device was $1.2{\times}2.4m^2$. A midwater trawl net of 2 ton hydrodynamic resistance was connected to the devices and towed with the velocity of 2.3 kts. Under these conditions the depth change of about 20m of the trawl net was obtained by controlling an angle or attack of $30^{\circ}$.