• Proceedings of KOSOMES biannual meeting
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• 2007.05a
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• pp.169-174
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• 2007

The purpose in having a control rod an a buoy system is to control the motion of it. The system may be composed entirely af a single circular cylinder finder and a lang mooring anchor cable. A control rod has one function to perform in meeting its purpose, and that is to develop a control force in consequence of its orientation and movement relative to the water. The forces and moments generated as a result of the effects of mutual interference, then determine the stability characteristics of the body. In this paper, the study of control-rod-attached buoy's 2-dimensional section was accomplished. model tests and numerical simulations had been carried out with different diameters of control rods. and varying the Reynolds number $Re=5,000{\sim}25,000$ based an the cylinder diameter(D=50mm) to. predict the performance af the body and the 2 frame particle tracking method had been used to obtain the velocity distribution in the flaw field 50mm circular cylinder had been used during the whale experiments and measured results had been compared with each other.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.17-17
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• 1998

Synchrotron radiation is produced when charged particles moving with relativistic velocities a are accelerated - for example, deflected by the bending magnets which guide the electron or p positrons in circular accelerators or storage rings. By using special focusing magnetic lattices i in the particle accelerators it is possible to make the dimensions of the particle beam very small with a hi맹 charge density which results in a light source with high b디lIiance. Synchrotron light h has important properties which make it ideal for a wide range of investigations in surface s science. The fact that the spectrum of electromagnetic radiation emitted in a bending magnet e extends in a continuum from the 얹r infra red region to hard x-rays means that it is id않I for a v variety of spectroscopic studies. Since there are no convenient lasers, or other really bright l light sources, in the vacuum ultraviolet and soft x-ray re.밍ons the development of synchrotron r radiation has enabled enormous advances to be made in this di펌C비t spectr따 re밍on. P Polarization-dependent measurements, for ex없nple ellipsometry or circular dichroism studies a are possible because the radiation has a well-defined polarization - linear in the plane of orbit w with additional right-circular, or left-circular, components for emission an생es above, or below, t the horizontal, respectively. Since the synchrotron light is emitted from a bunch of charge c circulating in a ring the light is emitted with a well-defined time structure with a short flash of l light every time a bunch passes an exit port. The time structure depends on the size of the ring a and the number and sequence of filling of the bunches. A pulsed light source enables time¬r resolved studies to be performed which provide direct information on the lifetimes and decay m modes of excited states and in addition opens up the possibility of using time of flight t techniques for spectroscopic studies. The fact that synchrotron radiation is produced in a clean u ultrahi야 vacuum environment is of gr않t importance for surce science studies. The current t비rd generation synchrotron light sources provide exceptionally high baliance and stability a and open up possibilities for experiments which would have been inconceivable only a short time ago.

• Steel and Composite Structures
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• v.52 no.2
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• pp.145-163
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• 2024

This paper presents six novel hybrid machine learning (ML) models that combine support vector machines (SVM), Decision Tree (DT), Random Forest (RF), Gradient Boosting (GB), extreme gradient boosting (XGB), and categorical gradient boosting (CGB) with the Harris Hawks Optimization (HHO) algorithm. These models, namely HHO-SVM, HHO-DT, HHO-RF, HHO-GB, HHO-XGB, and HHO-CGB, are designed to predict the ultimate strength of both rectangular and circular reinforced concrete (RC) columns. The prediction models are established using a comprehensive database consisting of 325 experimental data for rectangular columns and 172 experimental data for circular columns. The ML model hyperparameters are optimized through a combination of cross-validation technique and the HHO. The performance of the hybrid ML models is evaluated and compared using various metrics, ultimately identifying the HHO-CGB model as the top-performing model for predicting the ultimate shear strength of both rectangular and circular RC columns. The mean R-value and mean a20-index are relatively high, reaching 0.991 and 0.959, respectively, while the mean absolute error and root mean square error are low (10.302 kN and 27.954 kN, respectively). Another comparison is conducted with four existing formulas to further validate the efficiency of the proposed HHO-CGB model. The Shapely Additive Explanations method is applied to analyze the contribution of each variable to the output within the HHO-CGB model, providing insights into the local and global influence of variables. The analysis reveals that the depth of the column, length of the column, and axial loading exert the most significant influence on the ultimate shear strength of RC columns. A user-friendly graphical interface tool is then developed based on the HHO-CGB to facilitate practical and cost-effective usage.

• Korean Journal of Environmental Agriculture
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• v.18 no.4
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• pp.378-383
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• 1999

Changes of the spectroscopic characteristics of the organic matter fractions and circular filter paper chromatograph were assessed for the bark and piggery manure composts during the composting. as an approach to base the criteria of the compost maturity evaluation. Contents of humic acid-C (HA-C) and fulvic acid-C (FA-C) in both bark and piggery manure composts were decreased as the composting got closer to maturity, but the ratios of HA-C/FA-C were increased. During the composting. ${\Delta}log$ K values were decreased, but RF values were increased. Humic acid of the mature bark compost after 120 days of composting was A-type, as compared to Rp-type for the raw bark and B-type for the immature compost. However. humic acid of the mature piggery manure composts after 40 days of composting was B-type, indicating the humification of the organic matter fractions continued at this stage. Circular filter paper chromatograph of the mature bark compost exhibited the regular sawteeth pattern at the edge, but that of the mature piggery manure showed an irregular sawteeth pattern. Results demonstrated that spectroscopic characteristics and circular filter paper chromatograph of the organic by-product composts might be employed for the compost stability assessment.

• Korean Journal of Veterinary Service
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• v.31 no.3
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• pp.375-384
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• 2008

This study was performed to establish the discrimination of the corpus albicans that were formed after normal parturition and abortion in Holstein, The corpus albicans were obtained from 504 cows and 506 heifers slaughtered in the Agricultural Cooperative's Livestock Products Joint Market of Seoul City from March 2007 to October 2007. The difference in a gross examination (morphology, fibrogenesis, deposit state, color, and size) among the fixtures that exist in their ovaries was investigated. All of the cows had corpus albicans in their ovaries: 423 cows (83.9%) had less than three corpus albicans, 81 (16.1%) had more than four. In the heifers, however, 463 (91.05%) had no corpus albicans, 39 (7.7%) had one, and four (0.8%) had more than two. In the types of corpus albicans 73.2% of the cows had oval-type, 14.4% had circular-shaped, 12.4% had irregular-type. In the aborted heifers, however, oval-type appeared in 88.6% and circular-shaped appeared in 11.4%, and no irregular-type was found. There was no significant difference in the fibrogenesis and size of corpus albicans between cows and aborted heifers. However, slight difference in the color of the corpus albicans was observed between two types. In conclusion, it is not easy to discriminate by gross examination of ovary between cows and aborted heifers in the slaughter house.

• Steel and Composite Structures
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• v.26 no.4
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• pp.485-499
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• 2018

In this paper, a hollow steel tube (HST) shear connector is proposed for use in a slim-floor system. The HST welded to a perforated steel beam web and embedded in concrete slab. A total of 10 push-out tests were conducted under static loading to investigate the mechanical behavior of the proposed HST connector. The variables were the shapes (circular, square and rectangular) and sizes of hollow steel tubes, and the compressive strength of the concrete. The failure mode was recorded as: concrete slab compressive failure under the steel tube and concrete tensile splitting failure, where no failure occurred in the HST. Test results show that the square shape HST in filled via concrete strength 40 MPa carried the highest shear load value, showing three times more than the reference specimens. It also recorded less slip behavior, and less compressive failure mode in concrete underneath the square hollow connector in comparison with the circular and rectangular HST connectors in both concrete strengths. The rectangular HST shows a 20% higher shear resistance with a longer width in the load direction in comparison with that in the smaller dimension. The energy absorption capacity values showed 23% and 18% improvements with the square HST rather than a headed shear stud when embedded in concrete strengths of 25 MPa and 40 MPa, respectively. Moreover, an analytical method was proposed and predicts the shear resistance of the HST shear connectors with a standard deviation of 0.14 considering the shape and size of the connectors.

• Journal of Animal Environmental Science
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• v.8 no.2
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• pp.79-86
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• 2002

This study was conducted to collect basic data about the effects of ventilation types on the interior environment of the enclosed farrowing-nursery pig house in Anseong, Icheon and Jeungpyong. Surveyed ventilation types in the enclosed farrowing-nursery pig house are classified in to 4 types. In V1 type, air enters through a planar slot inlet placed on the juncture of the entering wall and exit through the chimney fan outlet; in V2 type, air enters through a perforated ceiling inlet and exits chimney fan outlet(V2); in V3 type, air enters through a circular duct inlet and exit chimney fan outlet(V3); in V4 type, enters through a circular duct inlet and exits side wall exhaust fan outlet(V4). Temperature, relative humidity, air velocity and ammonia concentration($NH_3$) were measured in the interior of swine building in the summer. Interior temperature was not remarkably different in all ventilation types in this study. However, temperature of the V4 was somewhat lower than that of the other types. Air velocity of the V4 was higher and $NH_3$ concentration of the V4 was lower than those of other ventilation types. It is suggested that the V4 ventilation type be applicable in the enclosed farrowing-nursery pig house in Korea.

• Journal of the Korea Society of Computer and Information
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• v.15 no.12
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• pp.11-18
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• 2010

In this paper, We suggest new strategies on non-interactive agents applied in a prey pursuit problem of multi agent research. The structure of the prey pursuit problem by grid space(Four agent & one prey). That is allied agents captured over one prey. That problem has long been known in interactive, non-interactive of multi agent research. We trying hard to find its own solution from non-interactive agent method on not in the same original environment(circular environment). We used ACS applied Direction vector to learning and decide on a direction. Exchange of information between agents have been previously presented (an interactive agent) out of the way information exchange ratio (non-interactive agents), applied the new method. Can also solve the problem was to find a solution. This is quite distinct from the other existing multi agent studies, that doesn't apply interactive agents but independent agent to find a solution.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.407-408
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• 2001

This paper describes the effects of varying the minor flow on particle collection efficiency and particle concentration in small cyclones. A cyclone haying a minor flow pumped out from its dust outlet is referred to as a virtual cyclone in this study although the terminology has been used for other types of devices (Torczynski and Rader, 1997). The virtual cyclones tested here have a rectangular inlet and circular outlet similar to the conventional cyclone. (omitted)

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2856-2858
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• 2000

This paper proposes a scan code method for obstacle avoidance of mobile robot. Obstacles detected in a circular window are converted to scan codes and then to the steering angle. The safe rotating radius is obtained by the scan code to avoid the collision between robot and obstacle and. the minimum distance for rotation is calculated. Effectiveness of the method is illustrated through simulations, and the results show that the proposed method can be efficiently implemented to an unknown environment.