• Transactions of Materials Processing
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• v.8 no.3
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• pp.245-251
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• 1999

In this study, the experimental considerations of the friction factors are presented in a few cases. The friction factors in the cases of, first, the drawing quality material, SPC3C through the non-coated die of base material. GC30, secondly, SPCC through the Cr-coated GC30 die, and lastly. SPCC through the TD heat treated STD11 die, are measured experimentally both for the increasing die temperature and the blank holding forces. The results show no considerable variations of the value of friction coefficients according to the change of both the die temperature and the die treating conditions.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.174-177
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• 2008

The amount of incident solar rays on inclined surfaces with various directions has Since the atmospheric clearness index is main factor for evaluating atmosphere environment, it is necessary to estimate its characteristics all over the major cities in Korea Peninsula. We have begun collecting clearness index data since 1982 at 16 different cities in South Korea and estimated using empirical forecasting models at 12 different stations over the North Korea from 1982 to 2006. This considerable effort has been made for constructing a standard value from measured data at each city. The new clearness data for global-dimming analysis will be extensively used by evaluating atmospheric environment as well as by solar application system designer or users.

• Journal of the Mineralogical Society of Korea
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• v.1 no.1
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• pp.32-39
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• 1988

The effect of soil forming factors on the pedogenesis of basaltic volcanic ash soils and the influence of allophane material on soil properties have been investigated on 5 chronosequence soils situated from at the near sea coast up to the foot slope of Mt. Halla in Jeju Island. Time seems to be the important soil forming factor which today differentiates soil of the Island. Songag and Donghong soils developed in lower elevations are older and somewhat less influenced by ash shower. However, soils developed at higher elevations, Pyeongdae and Heugag, are rather younger and strongly influence by the ash. It is also proved that the parent materials are very heterogeneous. They mainly are basaltic with some contamination of acidic volcanic ashes and continental aeolian deposits where a considerable amount of quartz encountered in most soils studied. Many physico-chemical properties of soil, such NaF pH, phosphate sorption power, pH and extractable acidity are parameters to differentiate andepts and non-andeptic soils.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.512-517
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• 2009

Resistance factors for static bearing capacity of driven steel pipe piles were calibrated in the framework of reliability theory. A comprehensive foundation design case study on an actual bridge was performed using resistance factors developed in this study. Comparing with Allowable Stress Design (ASD), LRFD design method provides quantitative evaluation of safety level of designed foundation and exhibits considerable potential economy in design.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.107-111
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• 2003

The need for this study must be considerable, as being activate of green roofs research that the organization and construction obtain access to more development technologies. Nevertheless, the green roofs system has begun to apply since 1980's, the green roofs technology was restricted to develop without verification of technologies such as a load or water leakage. There is a limit as urethane waterproofing to almost domestic waterproofing materials and methods of construction for general green roofs. The introduction of materials and methods of construction which are appropriated to property of green roofs could be a decisive factor in a long-range durability and economical maintenance cost, moreover. it support to variety construction system and organization. This present paper describes a necessity of waterproofing and root barrier system is one of the sub-organization based on green roofs construction. which have enormously large impact on the durability.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.34
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• pp.51-60
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• 1995

The key competition factor of manufacturing industries has progressively changed from cost to quality and time. Recently, the manufacturing environments more rapidly change than before. So, many companies want to introduce a advanced manufacturing system like CIMS to meet various user's needs and short delivery. But there is a considerable gap between the decision to invest and the achievement of promised benefits. Managers, generally, cannot afford CIM invesment unless they can determine beforehand that CIM will work in thier company and that will provide a coherent strategy and satisfactory return on investment In many cases, it is impossible to justify CIM investment by only economical analysis. Decision making problems like CIM investment are of a multiple objective nature. So, decision making process and multiattribute utility function are very useful methods to evaluate CIM justification In this paper, we described the key functions of CIM justification evaluation using IDEF methodology and developed the applicattion procedure of DMP and MUF method for CIM justification.

• Journal of the Korean Solar Energy Society
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• v.27 no.2
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• pp.45-52
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• 2007

Since the atmospheric clearness index is main factor for evaluating global-dimming of atmosphere environment, it is necessary to estimate its characteristics all over the major cities in Korea. We have begun collecting clearness index data since 1982 at 16 different cities and considerable effort has been made for constructing a standard value from measured data at each city. The new clearness data for global-dimming analysis will be extensively used by evaluating atmospheric environment as well as by solar PV application system designer or users. From the results, we can conclude that 1) Yearly mean 61.9% of the atmospheric clearness index was evaluated for clear day all over 2) A significant difference of atmospheric clearness index is observed between 1982-1989 and 1990-1997, 1998-2005 through 16 different cities in Korea.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.6
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• pp.477-484
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• 2002

A numerical investigation of the performance of the plate heat exchanger with rectangular winglet is conducted to examine the combined effect of vortex generator and louver fins. Velocity and temperature fields and spanwise averaged Nu and friction factor are presented. Enhancement of heat transfer and flow loss penalty is evident. A Parametric study of three factors (Re, angle of attack and louver angle) with levels of 5 (Re= 300, 500, 700, 900, 1100), 4($\alpha=15^{\circ}, 30^{\circ}, 45^{\circ}, 90^{\circ},$), and 4($\beta=0^{\circ}, 15^{\circ}, 30^{\circ}, 45^{\circ}$), respectively, indicates the performance defined by the ratio of heat transfer enhancement to flow loss penalty shows monotonic behavior for each parameter alone but the interactions between parameters is found to be considerable effect on the performance of heat exchanger and should be considered in design. The effect of stamping is also examined.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.607-614
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• 2002

For the accurate analysis of crack problems, considerable nodal refinement near the crack tip to capture singular stress field with sufficient accuracy to provide a useful computation of stress intensity factor is required. So, in this paper, adaptive nodal refinement scheme is proposed where nodes in restricted cell regions centered at crack tip are arranged in array for enhanced spatial resolution and adaptivity. With only cell-wise adaptive refinement scheme around crack tip fields, singularity of crack tip is sufficiently described to expect a successive crack propagate direction. Through numerical tests, accuracy of the proposed adaptive scheme is investigated and compared with the finite element and experimental results. By this implementation, it is shown that high accuracy is achieved by using iterative cell-wise solution method fur analyzing crack propagation problems.

• Journal of the Korean Solar Energy Society
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• v.31 no.1
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• pp.87-92
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• 2011

Since the atmospheric clearness index is main factor for evaluating atmosphere environment, it is necessary to estimate its characteristics all over the major cities in Korea. We have begun collecting clearness index data since 1982 at 16 different cities and considerable effort has been made for constructing a standard value from measured data at each city. The new clearness data will be extensively used by evaluating atmospheric environment as well as by solar application system designer or users. Yearly mean 64% of the atmospheric clearness index was evaluated for clear day all over, and significant difference of horizontal global insolation is observed between 1982~1986 and 1987~1991, 1992~1996, 1997~2001, 2002~2009 through 16 different cities in Korea.