• Structural Engineering and Mechanics
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• v.90 no.4
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• pp.325-343
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• 2024

Triple-tower double-cable suspension bridges have increased confinement stiffness imposed by the main cable on the middle tower, which has bright application prospects. However, vertical bending and torsional vibrations of the double-cable and the girder are coupled in such bridges due to the hangers. In particular, the bending vibration of the towers in the longitudinal direction and torsional vibrations about the vertical axis influence the vertical bending and torsional vibrations of the stiffening girders, respectively. The conventional analytical algorithm for assessing the dynamic features of the suspension bridge is not directly applicable to this type of bridge. This study attempts to mitigate this problem by introducing an analytical algorithm for solving the triple-tower double-cable suspension bridge's natural frequencies and mode shapes. D'Alembert's principle is employed to construct the differential equations of the vertical bending and torsional vibrations of the stiffening girder continuum in each span. Vibrations of stiffening girders in each span are interrelated via the vibrations of the main cables and the bridge towers. On this basis, the natural frequencies and mode shapes are derived by separating variables. The proposed algorithm is then applied to an engineering example. The natural frequencies and mode shapes of vertical bending and torsional vibrations derived by the analytical algorithm agreed well with calculations via the finite element method. The fundamental frequency of vertical bending and first- and second-order torsion frequencies of double-cable suspension bridges are much higher than those of single-cable suspension bridges. The analytical algorithm has high computational efficiency and calculation accuracy, which can provide a reference for selecting appropriate structural parameters to meet the requirements of dynamics during the preliminary design.

• Journal of architectural history
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• v.9 no.1 s.22
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• pp.7-25
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• 2000

The purpose of this study is focused to the historic changes of Yungnam-Ru(嶺南樓), which are based on the site layout, and architectural forms in architectural building history and historic periods analyzed with the historic reference, paintings, and photos. This study is to search the alteration of the types of axis and the formation of spaces in Yungnam-Ru which is the Ru-Gak(樓閣) The conclusion of the architectural changes from the historic period and architectural form which is the belows. The first Yungnam-Ru by name had been used to be called, before it was re-called Yungnam-Ru by Kim Ju in 1365. Therefore, the hypothesis in naming Yungnam-Ru form assumption that the building under the name of Yungnam-Ru was re-named by Kim Ju from the Old Budist Temple called Yungnam-Sa, should re-considered in history. The second, it is considered that Milyang-Sibyi-Kyungdo(密陽十二景圖) as the painting can only be seen the site layout in 1542. It could be compared the differences of the site layouts from in 1542 to the present time. At that time Nyungpadang(凌派堂) was connected the main buildings called Yungnam-Ru Chimrudang(沈流堂),building was seperated with the Yungnam-Ru at that period. In 1542, the main Building(Yungnam-Ru) was consist of 5 spans of columns(from the front) and 2 spans of columns(from the side). Now, the main Building(Yungnam-Ru) has the 5 spans of columns from the front, and two spans of columns short from the side, compared to the present facade. At the past, Chimrudang(building) has the two spans of columns and one span of columns short, compared to the present facade. The third, It supposed that main building, Nyungpadang and Chimrudang in the composite of facade was connected with Wolrang(月廊) and Hunrang(軒廊) after invatioin from japan in 1592. 1844, (Chosun dynasty, Hunjong 10) the Yungnam-Ru was re-builted by maintaining the same concept in site layout of the past, and finally the three buildings was put together with Wolrang and Hunrang. As a result, the plan of the Yungnam-Ru was expanded with many aspects. From 1542 to 1844, the present site-layout gradually completed with three buildings which was spatially connected. The forth, in the middle age of Chosun dynasty, after added Gaeksa(客舍), the building is for the government officer staying temporally from outside province) in the site, the site layout was greatly changed with volume of building. In 1844, the Yungnam-Ru as the Nugak belongs to Miljukwan(密州館) was expanded spacially and formally. After that time, the burned buildings could not have been re-built because of aspects in government ability and economical ability.

• Journal of the Korean Magnetics Society
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• v.2 no.3
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• pp.268-275
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• 1992

The multicurrent method composed of a main and auxiliary currents was used to make the uniform field near the solenoid center. The auxiliary currents were determined to give the spherical symmetry in the field uniformity from the Legendre polynomials. Rabi's NMR system using polarized flowing water has been constructed and the field of a 4-current solenoid has been determined from the resonance frequency. The field uniformity along the solenoid axis has been improved by adjusting the auxiliary currents.

• The Journal of Fisheries Business Administration
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• v.15 no.1
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• pp.114-130
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• 1984

The structure of food demand is being changed according to the improvement of living standard. Moreover, the intake of animal protein is stepping up. This paper considers how much fresh-fish is consumed as source of animal protein and what extent fresh-fish have substitutive relation for meat with special reference to the change of income and price of fresh-fish and meat. And it is thought to be important work to estimate demand of fresh-fish in attemps to the prediction of food consume pattern and fishing industries in the future. For this estimation, the substitutive relation of fresh-fish and meat is essentially studied. The main conclusions of this study can be drawn as follows: 1. Fresh-fish and meat have substitutive relation on price axis. By the way, increase in demand of A (fresh-fish which have comparatively low price) can be expected according to the low of it's price against meat, but B (fresh-fish wihich have comparatively middle-high price) have peculiar demand without substitutive relation for meat. 2. Demand of A and B rise according to the income increases. 3. It is not sufficient to explain substutive relation of fresh-fish and meat without income variable. 4. Income increases bring about the more increase in demand of B than A. By the way, price increases bring about the decrease of it's consume expenditure, but A have fundamental demand as the source of animal protein. 5. In future, the intake of animal protein will step up. By the way, meat will occupy the more portion of the source of animal protein than fresh-fish.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.57-62
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• 2004

This paper deals with a waypoint trajectory following problem for the tilt-rotor UAV under development in Korea (TR-KUAV). In this problem, dynamic model inversion based on the linearized model and Sigma-Phi neural network with adaptive weight update are involved to realize the waypoint following algorithm for the vehicle in the helicopter flight mode (nacelle angle=0 deg). This algorithms consists of two main parts: outer-loop system as a command generator and inner-loop system as stabilizing controller. In this waypoint following problem, the position information in the inertial axis is given to the outer-loop system. From this information, Attitude Command/Attitude Hold logic in the longitudinal channel and Rate Command/Attitude Hold logic in the lateral channel are realized in the inner-loop part of the overall structure of the waypoint following algorithm. The nonlinear simulation based on the TR-KUAV is carried out to evaluate the stability and performance of the algorithm. From the numerical simulation results, the algorithm shows very good tracking performance of passing the waypoints given. Especially, it is observed that ACAH/RCAH logic in the inner-loop has the satisfactory performance due to adaptive neural network in spite of the model error coming from the linear model based inversion.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.628-632
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• 2003

An intelligent miniature humanoid robot system is designed and implemented as a platform for researching walking algorithm. The robot system consists of a mechanical robot body, a control system, a sensor system, and a human interface system. The robot has 6 dofs per leg, 3 dofs per arm, and 2 dofs for a neck, so it has total of 20 dofs to have dexterous motion capability. For the control system, a supervisory controller runs on a remote host computer to plan high level robot actions based on the vision sensor data, a main controller implemented with a DSP chip generates walking trajectories for the robot to perform the commanded action, and an auxiliary controller implemented with an FPGA chip controls 20 actuators. The robot has three types of sensors. A two-axis acceleration sensor and eight force sensing resistors for acquiring information on walking status of the robot, and a color CCD camera for acquiring information on the surroundings. As an example of an intelligent robot action, some experiments on playing soccer are performed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.313-317
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• 2005

The facility improvement for hot firing test of combustion chamber having thrust of 30-tonf class and chamber pressure of 60bara were performed at ReTF in KARI. The KSR-III main engine having combustion pressure of 13bara and thrust of 12.5tonf had been successfully tested in this facility. To increase the capability of the facility, the feeding and the trust measurement system have been modified. The modification of the feeding system plays also a role of ensuring the stability of propellant supply and two step ignition sequence of combustion chamber. The one-axis thrust measurement system of up to 60tons has been newly manufactured and installed in test stand and the water/kerosene supply lines with high pressure vessel of $4m^3$ and gas nitrogen vessel of $10m^3$ have been designed for regenerative cooling system. The results of cold flow test show that this facility has been successfully improved to satisfy the requirement for hot firing test of high performance combustor.

• Journal of architectural history
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• v.14 no.3 s.43
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• pp.77-88
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• 2005

This study is to find out the characteristics of the changes of the site layout in Beopjusa which was built on Maitreya faith in the Shilla.. According to the analysis of it in this study, we make conclusions as follows; 1) The reconstruction of Beopjusa means a start in Dhamalsama(法相宗) and then it was supposed to be Buddhist temple which was formed by intersecting axis of centering around a wooden pagoda(捌相殿) with a main Buddhist hall and a lecture hall. 2) After the middle of Koryo dynasty, Beopjusa was changed to building layout of intersecting with Yongwabojeon(龍華寶殿) and Daeungbojeon(大雄寶殿) because of harmony with Avatamsaka(華嚴宗) and Dhamalsama centering around Avatamsaka. 3) The buildings of Zen Buddhism was built in the early Chosun dynasty owing to a prevalence of Zen Buddhism in the late Koryo dynasty. And since 17th century, Buddhist halls were each built in their a faith system according to interpenetrated Buddhism(通佛敎). 4) The courtyard type of mountainous district was made on interpenetrated Buddhism. On the other hand, the site layout of Beopjusa is being maintained by centripetal spatial organization through the wooden pagoda as object.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.1
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• pp.33-43
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• 1998

High cutting speeds and feeds are essential requirements of a machine tool structure to accomplish its basic function which is to produce a workpiece of the required geometric form with an acceptable surface finish at as high a rate of production as is economically possible. Since the bearings in high speed spindle units are the main heat source of the total cutting system, in this work, the thermal characteristics of the spindle bearing system with a tilting axis were investigated using finite element methods to improve the performance of the spindle bearing system. Based on the theoretical results, a specially designed prototype spindle bearing system has been manufactured. Using the manufactured spindle bearing system, the thermal characteristics were measured. From the comparison of the experimental results with the theoretical ones, it was found that the finite element method predicted well the thermal characteristics of the spindle bearing system.

• Journal of Environmental Science International
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• v.23 no.9
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• pp.1537-1549
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• 2014

The objectives of this study were to analyze reservoir trophic state, based on Trophic State Index (TSI), spatial variation patterns of three zones (riverine, transition, and lacustrine zone), and empirical models through 20-years long-term data analysis. Trophic variables of TP and CHL-a were highest during the summer monsoon, and decreased along the main axis from the riverine to lacustrine zone. In the mean time, TN did not show the trend. Ratios of N:P and Secchi disc transparency (SD) increased from the riverine to lacustrine zone. The analysis of trophic state index (TSI) showed that mean TSI (TP) and TSI (CHL-a) were 62 and 57, respectively, and these values were highest in the transition zone during the summer. This zone should be managed well due to highest lake water pollution. The analysis of Trophic State Index Deviation (TSID) showed that algal growth was primarily limited by light penetration, and this was most pronounced in the monsoon season. The analysis of empirical models showed that the value of $R^2$, based on CHL-SD model, was 0.30 (p < 0.0001) in the transition zone and the $R^2$, based on TP-SD model, was 0.41 (p < 0.0001) in the transition zone.