• Journal of the Korean Society for Precision Engineering
• /
• v.3 no.1
• /
• pp.50-59
• /
• 1986

Adaptive Model Following Control (AMFC) technique is applied to develop a robot manipulator control system, which can deal successfully with the complex dvnamics of the manipulator. Main concerns of this study are put on the problem reducing the chatter amplitude of control signal yielded by the unit vector control law that was proposed [10] previously for AMFC of the manipulatro, and the effect- iveness of the algorithm when implemented practically. To see the effectiveness of modified method, computer simulations using new and old control law are carried out and compared, and the modified one id implemented in RHINO XR-II robot system recon- structed partially to enable torque control.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.995-1000
• /
• 2000

In this paper. a mechanistic model is first constructed to predict three-dimensional cutting forces, and the uncut chip th thickness is calculated by following the movements of the position of the center of a cutter, which varies with the nominal feed, cutter deflection and runout. For general implementation to a real machining, this paper presents the method that determines constant cutting force coefficients, irrespective of the cutting conditions or cutter rotation angles. In addition, this study presents the approach which estimates runout-related parameters. the runout offset and its location angle, using only one measurement of cutting forces. For more accurate cutting force predictions, the size effect has to be considered in the cutting force model. In this paper, two approximate methods are suggested since the strict approach is practically impossible due to a measurement problem. The size effect is individually considered for narrow and wide cuts.

• Journal of Korean Society of Transportation
• /
• v.5 no.1
• /
• pp.59-74
• /
• 1987

A prediction is an indispensable element to research of Social Science, especially in Regional planning, City planning, and Transportation planning. Since 1930s, varieties of prediction methods have been developed. In the 1980s, numerical models have been used by high-developed computers. even though the numerical models can be figured mathematically, it could not be applied practically due to it's expertness and complicateness. And even professional planners often can not use their ideas which are valuable experiences in prediction process, because they are not knowledgable for numerical models. The YSIM developed by author, is available as follows. i)Numerical modeling of professional experiences ii)Providing a foundation of large-scale model iii) Understanding of research object structure The YSIM make use of matrix to identify the system structure which is similar to the Cross Impact Method. To evaluated the YSIM availabilities, it is compared with the early developed methodologies such as KSIM, QSIM, and SPIN. As the result, it was confirmed that YSIM was more accurate in the prediction. The algorithms in YSIM is programmed for use of PCs.

• Journal of Technology Innovation
• /
• v.5 no.1
• /
• pp.266-287
• /
• 1997

The purpose of this paper is to purpose methods and procedures by which we can set up technology planning scheme essential for R'||'&'||'D(or technology) planning in public sector (governmental and government-sponsored institutions), and can develop and select "main R'||'&'||'D projects" which are crucial to R'||'&'||'D planning, were quite specifically discussed in case of I'||'&'||'T(Information '||'&'||' Telecommunications) sector, so that they may not remain theoretical but may be practically applicable to real R'||'&'||'D programs. In this paper, the concept of technology planning was defined as a procedure for establishing nominal planning to acquire technologies efficiently for a specific sector. More detailed definition optimal technology-acquisition strategy, i.e., analyzing technological development '||'&'||' environ-ment, establishing R'||'&'||'D objectives as promising technology opportunities, selecting main R'||'&'||'D projects, allocating resources and so on."The"main R'||'&'||'D projects by technology sectors and by planning phases and then deciding on priority. Scoring method was rsed in assessment phase. Summing up, this paper suggested technology planning scheme of methods and procedures for sorting out required technologies, developing and assessing public R'||'&'||'D projects, and finally selecting main R'||'&'||'D projects.

• Transactions of Materials Processing
• /
• v.13 no.1
• /
• pp.3-8
• /
• 2004

The improvement of dimensional accuracy for forged part is one of major goals in cold forging industry. There are many problems in controlling the dimension by the trial-and-error, especially for a precision forged gear. A FEM analysis has been used in developing the forging technology. However, FE techniques have to be reconfirmed for predicting accurately the dimension of forged part. In this study, the effects of elastic characteristics and temperature changes are investigated by the comparisons between experimental and FEA in cold forging. When FE models related with elastic characteristics are considered practically, FE results could predict the part dimension within the range of $10\mu\textrm{m}$. And if thermal effects also are considered additionally, the predicted dimensions are well coincided with the experimental down to about $5\mu\textrm{m}$.

• Transactions of Materials Processing
• /
• v.6 no.3
• /
• pp.233-238
• /
• 1997

The estimation of the forming force required for metal forming process is unavoidable for selecting suitable machine and dimensioning die and punch parts. For this purpose the upper-bound method turns out to be very practical in simple two-dimensional cases under well-known boundary conditions. However, the application of this method for complicated two-or three-dimentional cases is very limited or practically impossible. The modified application of FEM in a manner of applying the upper bound method(the so-called Upper-bound Finite Element Simulation Method) fortunately provides the posibility of getting important information about the forming process in a simple and quick way before realizing the process on the machine. It is expected to function successfully even in three-dimentional cases. The application procedure has been explained for two-dimensional cases and its usefulness shown.

• Transactions of Materials Processing
• /
• v.18 no.8
• /
• pp.596-600
• /
• 2009

Finite element simulation is an alternative method to practically find the forming limit diagram(FLD). In this paper, the novel fracture criterion is utilized to predict the FLD in conjunction with finite element analysis for sheet forming. The principal scheme of the fracture criterion in this paper is that growth of the micro voids leads up to fracture in the viewpoint of micro-mechanics. The numerical FLD is verified by results of the out-of plane stretching test using hemispherical punch. The verification is also conducted about two types of material. These results are in good accord with the experimental results. Especially, the proposed scheme is appropriate to predict FLDs for a restricted material with low ductility after the instability point or ultimate tensile strength.

• Journal of Veterinary Clinics
• /
• v.9 no.2
• /
• pp.473-481
• /
• 1992

To elucidate the applicability of the wide latitude X-ray film for radiographic diagnosis and treatment of diseases in small animals, the quality of the wide latitude film was compared with that of the standard latitude film which is commonly used in veterinary clinic. The images of head, neck, thorax, abdomen, extremities and joints were radiographed with the wide latitude and standard latitude film in fourteen dogs. In soft tissues such as abdominal organs, lung, skin, mammary glands, the clearer and higher contrast of the image was observed on the wide latitude film. And these advantages were more apparent in pneumoeritoneography. Therefore. it can be suggested that the wide latitude film is practically useful for the evaluation of the images of soft tissues, and also can be used on hard tissue radiography with the same quality as the standard latitude film.

• Communications for Statistical Applications and Methods
• /
• v.16 no.5
• /
• pp.731-743
• /
• 2009

The interval estimation for binomial proportion has been treated practically as well as theoretically for a long time. In this paper we compared the properties of major confidence intervals and summarized current issues for coverage probability and interval length which are the criteria of evaluation for confidence interval. Additionally, we examined the three topics which were considered in using the binomial confidence interval in the field. And finally we discussed the future studies for a low binomial proportion.

• Journal of Korean Society of Water and Wastewater
• /
• v.26 no.4
• /
• pp.547-554
• /
• 2012

As a national river remediation project has been completed, this study has a special interest on the capabilities to predict water levels at various points of the Geum River. To be endowed with intelligent forecasting capabilities, the author formulate the neuro-genetic algorithm associated with the short-term water level prediction model. The results show that neuro-genetic algorithm has considerable potentials to be practically used for water level forecasting, revealing that (1) model optimization can be obtained easily and systematically, and (2) validity in predicting one- or two-day ahead water levels can be fully proved at various points.