• Journal of the Korea institute for structural maintenance and inspection
• /
• v.4 no.4
• /
• pp.211-218
• /
• 2000

Many bridges are severely damaged by the overloaded heavy vehicle and the trend will become more serious because the traffic volume is continuously increasing. Currently, the vehicles with gross weights over 40 tonf or axle weight over 10 tonf are not allowed on the public road. However, this regulation is not based on a systematic study on the bridge capacity and assumed to be much too conservative depending on the vehicle types and bridge types. In this study, the permit weights of heavy vehicles of diverse axle spacings and axle load distribution are calculated considering the structural characteristics of bridge superstructures. In order to consider the various load effects of heavy weight vehicle crossings, three conditions are considered in the calculation of permit vehicle load. From the results, the permit vehicle weights of the simple girder bridges are calculated.

• Journal of Families and Better Life
• /
• v.21 no.2
• /
• pp.75-85
• /
• 2003

The purpose of this study was to investigate the attitudes toward divorce of young men and women. The data were collected by questionnaire from 425 respondents who resided in Sunchon. Statistical methods for the data analysis were frequencies, one-way ANOVA, t-test. The data analysis revealed that the young men and women accepted divorce as an alternative to unhappy marriage and there were significant gender differences in the attitudes toward divorce. Women accepted divorce more positively as an alternative than men in every conditions. Men accepted divorce remarkably as an alternative to unfaithful debauchery of spouse, but women accepted divorce extremely well as an alternative to wrongdoing of spouse. Most of young men and women were worried about children, but not a few of them did not perceived themselves as child rearer. This results showed that divorce will be increased and perceived differently by gender. The young men and women who had lower conservative familism, who were younger, and who had higher education responded more positively about divorce.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2471-2476
• /
• 2008

Turbulent flow and heat transfer to water at supercritical pressure flowing in vertical pipes is investigated using direct numerical simulation (DNS). A conservative space-time discretization scheme for variable-density flows at low Mach numbers is adopted in the present study to treat steep variations of fluid properties at supercritical pressure just above the thermodynamic critical point. The fluid properties at these conditions are obtained using PROPATH and used in the form of tables in the simulations. The buoyancy influence induced by strong variation of density across the pseudo-critical temperature proved to play an important role in turbulent flow and heat transfer at supercritical state. Depending on the degree of buoyancy influence, turbulent heat transfer may be enhanced or significantly deteriorated, resulting in local hot spots along the heated surface.

• Wind and Structures
• /
• v.3 no.4
• /
• pp.255-266
• /
• 2000

Wind-induced interference effects on a building are the result of one or more adjacent buildings modifying the flow of wind around it, which may result in a significant increase or decrease in wind loads on the building. Wind loading standards and codes of practice offer little guidance to the designer for assessing the effects of interference. Experimental results on interference effects indicate that code recommendations may be significantly low (unsafe) or uneconomically conservative. The paper presents results of an extensive experimental program to study the wind flow mechanisms and to quantify the extent of wind load modifications on buildings due to interference effects. These results have been simplified and presented from the point-of-view of design and codification for the case of two buildings. Based on these results, general guidelines and limiting conditions defining wind interference are formulated and discussed.

• Journal of Korean Foot and Ankle Society
• /
• v.16 no.1
• /
• pp.19-25
• /
• 2012

The ankle impingement syndrome is an established cause of ankle dysfunction. In most cases with suspected ankle impingement, the diagnosis can be possible on the basis of mechanism of injury involved and the clinical examination. An appropriate imaging study should be selected where clinical doubt about the exact diagnosis exists. Radiography plays an important role in the initial assessment of these conditions, especially in anterior and posterior impingement. Magnetic resonance arthrography seems to be the most accurate means of assessing the capsular abnormalities present in anterolateral and anteromedial impingement and for confirmation of possible concomitant injury. Surgical treatment can be considered for the patients who did not respond to conservative treatment for more than 6 months, and has a low complication rate and a high level of success.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.55 no.9
• /
• pp.409-413
• /
• 2006

In this paper, we propose a new sliding surface design method for a class of uncertain systems with mismatched unstructured uncertainties. The uncertain system under consideration may have mismatched parameter uncertainties in the state matrix as well as in the input matrix. In terms of linear matrix inequalities (LMIs), we give a sufficient condition for the existence of linear sliding surfaces guaranteeing the asymptotic stability of the sliding mode dynamics. And, we give an LMI parameterization of such linear sliding surfaces together with switched feedback control laws. Our LMI condition can be less conservative than the existing conditions and our result supplement the existing results. Finally, we give a numerical example showing that our method can be better than the previous results.

• Proceedings of the KIEE Conference
• /
• 1998.11a
• /
• pp.295-297
• /
• 1998

This paper shows characteristics of fault current division factor $S_f$, which is a ratio of earth- return current to total fault current, at a substation fed exclusively by power cables under unsymmetrical fault condition, such as single line-to-ground fault. In substation grounding system design, $S_f$ is a very important factor determining GPR, touch and step voltage at a substation under fault condition. In case of substations fed by overhead lines, 40-60% of $S_f$ has been typically used, although it is a very conservative value with no other network conditions considered. It is authors' hope that $S_f$ presented in this paper could hopefully be a basic reference in designing of substation grounding system, especially for a substation fed exclusively by power cables.

• Structural Engineering and Mechanics
• /
• v.41 no.3
• /
• pp.365-378
• /
• 2012

In this study, strength reduction factors are investigated for SDOF systems with period range of 0.1-3.0 s with elastoplastic behavior considering soil structure interaction for 64 different earthquake motions recorded on different site conditions such as rock, stiff soil, soft soil and very soft soil. Soil structure interacting systems are modeled and analyzed with effective period, effective damping and effective ductility values differing from fixed-base case. For inelastic time history analyses, Newmark method for step by step time integration was adapted in an in-house computer program. Results are compared with those calculated for fixed-base case. A new equation is proposed for strength reduction factor of interacting system as a function of structural period of system (T), ductility ratio (${\mu}$) and period lengthening ratio (T/T). It is concluded that soil structure interaction reduces the strength reduction factors for soft soils, therefore, using the fixed-base strength reduction factors for interacting systems lead to non-conservative design forces.

• Nonlinear Functional Analysis and Applications
• /
• v.27 no.2
• /
• pp.405-432
• /
• 2022

Cracks in beams and shallow arches are modeled by massless rotational springs. First, we introduce a specially designed linear operator that "absorbs" the boundary conditions at the cracks. Then the equations of motion are derived from the first principles using the Extended Hamilton's Principle, accounting for non-conservative forces. The variational formulation of the equations is stated in terms of the subdifferentials of the bending and axial potential energies. The equations are given in their abstract (weak), as well as in classical forms.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.51 no.1
• /
• pp.88-98
• /
• 2024

Patients with pediatric cancer often undergo multiple therapies, such as chemotherapy, radiation therapy, and stem cell transplantation. These treatments, while essential, can result in dental developmental issues, including hypodontia, microdontia, short roots, and delayed dental development. This report presents two cases of pediatric patients diagnosed with neuroblastoma who exhibited severe tooth mobility due to short roots as a complication of cancer treatment. Moreover, we investigated the conservative management of the patients' conditions using resin wire splints and orthodontic miniscrews for skeletal anchorage along with long-term follow-ups to evaluate their prognosis.