• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.3
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• pp.71-86
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• 1983

Current R.C. retaining wall design is bared on WSD, but the reliability based design method is more rational than the WSD. For this reason, this study proposes a reliability based design criteria for the cantilever retaining wall, which is most common type of retaining wall, and also proposes the theoretical bases of nominal safety factors of stability analysis by introducing the reliability theory. The limit state equations of stability analysis and design of each part of cantilever retaining wall are derived and the uncertainty measuring algorithms of each equation are also derived by MFOSM using Coulomb's coefficient of the active earth pressure and Hansen's bearing capacity formula. The levels of uncertainties corresponding to these algorithms are proposed appropriate values considering our actuality. The target reliability indices (overturning: ${\beta}_0$=4.0, sliding: ${\beta}_0$=3.5, bearing capacity: [${\beta}_0$=3.0, design for flexure: [${\beta}_0$=3.0, design for shear: ${\beta}_0$=3.2) are selected as optimal values considering our practice based on the calibration with the current R.C. retaining wall design safety provisions. Load and resistance factors are measured by using the proposed uncertainties and the selected target reliability indices. Furthermore, a set of nominal safety factors, allowable stresses, and allowable shear stresses are proposed for the current WSD design provisions. It may be asserted that the proposed LRFD reliability based design criteria for the R.C. retaining wall may have to be incorporated into the current R.C. design codes as a design provision corresponding to the USD provisions of the current R.C. design code.

• Journal of the Korea Concrete Institute
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• v.21 no.6
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• pp.753-761
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• 2009

This paper presents the test results of total 24 beam-end specimens to investigate the effect of high-strength concrete and cover thickness on the development resistance capacity in tensile lap splice length regions. Based on bond characteristics that an increase in concrete strength results in higher bond stress and shortening of the transfer length, cracking behavior that thin cover thickness induced a splitting crack easily and brittle crack propagation, current design code that development length provisions as uniform bond stress assumption was investigated apply as it. The results showed that as higher strength concrete was employed, not only development resistance capacity was influenced by cover thickness, but also more sufficient safety factor reserved shorter than the lap splice length provision in current design code. From experimental research results, high-strength concrete development length was not inverse ratio of $\sqrt{f_{ck}}$ but directly inverse of $f_{ck}$, and it is also said that there is a certain limit length of the embedded steel over which the assumption of uniform bond stress distribution is valid specially for high-strength concrete not having a same embed length such as normal-strength concrete in current design criteria hypothesis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.1
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• pp.43-53
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• 1985

This study proposes a reliability based design criteria for the steel bridge (H-beam, plate-girder and composite-beam), which is most common type of steel bridge, and also proposes the theoretical bases of nominal safety factors as well as load and rasistance factors based on the reliability theory. Major 2nd moment reliability analysis and design theories including both Cornell's MFOSM (Mean First Order 2nd Moment) Methods and Lind-Hasofer's AFOSM(Advanced First Order 2nd Moment) Methods are summarized and compared, and it has been found that Lind-Hasofer's approximate and an approximate Log-normal type reliability formula are well suited for the proposed reliability study. A target reliability index (${\beta}_0=3.5$) is selected as an optimal value considering our practice based on the calibration with the safety pravisions of the current steel bridge design code. Galambo's theory is used for the derivation of the algorithm for the evaluation of uncertainties associated with resistences by LRFD Format and SGST Format, whereas the magnitude of the uncertainties associated with load effects are chosen primarily by considering our level of practice. It may be concluded that the proposed LRFD reliability based design provisions for the steel highway bridge give more rational design than the current standard code for steel highway bridge.

• Magazine of the Korea Concrete Institute
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• v.8 no.6
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• pp.173-182
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• 1996

An experimental research was carried out to investigate the effect of thc compressive strength of concrete on the stirrup effectiveness in shear behavior of concrete beams. For this purpose. total 24 beams of section dimension of $300{\times}600mm$ were tested: 4 specimens without web reinforcement and 20 specimens with web reinforcement in the form of vertical stirrups. Main variables were two levels(norma1 and high strength) of the compressive strength of concrete and six types of t h e shear rcinfor.cement ratios. Prior to experiment, for given sections and assumed material constants, the reference shear reinforcement ratio(${\rho}_vACI$) which leads to the flexure failure using the provisions of the ACI Building Code(AC1 318-95) was calculated. and the shear reinforcement ratios were relatively selected from the value of ${\rho}_vACI$. From test results, it was shown that thc safety factor of ACI eyuation for p1,ediction of shear strength was decreased with increasing the compressive strength of concrete in beams without stirrups. However. it was observed that as the amount of' stirrup is increased, the safety factor for high strength conci,ete beams with high stirrup ratio is ensured more than that for normal strength concrete beams. Therefore i t appears that the stirrup effectiveness of high strength concrete beams is greater than that of normal strength concrete beams.

• The Korean Society of Law and Medicine
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• v.20 no.2
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• pp.3-39
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• 2019

Even after the Constitutional Court decided on August 23, 2012 that the provisions of abortion were constitutional, discussions on the abolition of abortion continued. The controversy about abortion is not only happening recently, but it has already existed since the time when the Penal Code was enacted, and it shares the history of modern legislation with the Republic of Korea. Legislators whom submitted amendment while insisting upon the eradication of abortion in the process of enacting criminal law at that time, presented social and economic adaptation reasons as the core reason. From then on, the abolition of abortion has been discussed during the development dictatorship, but this was not intended to guarantee women's human rights, but it was closely connected to the national policy projects of "Contraception" and "Family Planning" of the Park's dictatorship. Since then, the enactment of the Mother and Child Health Law, which restrictively allow artificial abortion, was held on February 8, 1973, in an emergency cabinet meeting that replaced the legislative power after the National Assembly was disbanded. It became effected May 10th. The reason behind the Mother and Child Health Law that included legalization of abortion in part was that the Revitalizing Reform at that time did not allow any opinion, so it seem to be it was difficult for the religious to express opposition. The "Maternal and Child Health Law" enacted in this way has been maintained through several amendments. It can be seen that the question of maintenance of abortion has been running on parallel lines without any significant difference from the time when the Penal Code was enacted. On August 23, 2012, the Constitutional Court decided that the Constitutional Opinion and the unonstitutional Opinion were 4: 4. However, it was decided by the Constitution without satisfying the quorum for unconstitutional decision of the Constitutional Court. This argument about abolition of abortion is settled for the the time being with the decision of the constitutional inconsistency of the Constitutional Court, and now, the National Assembly bears the issue of new legislation. In other words, the improved legislation must be executed until December 31, 2020, and if the previous improved legislation is not implemented, the crime of abortion (Article 269, Paragraph 1, Article 270 of the Criminal Code) Article 1 (1) will cease to be effective from 1 January 2021. Therefore, in the following, we will look into the reason of the Constitutional Court's constitutional discordance adjudication on criminal abortion(II), and how it structurally differs from the previous Constitutional Court and the Supreme Court. After considering key issues arised from the constitutional discordance adjudication(III), the legislative direction and within the scope of legislative discretion in accordance with the criteria presented by the Constitutional Court We reviewed the proposed revisions to the Penal Code and the Mather and Child Health Act of Korea(IV).

• The Korean Society of Law and Medicine
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• v.16 no.2
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• pp.159-193
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• 2015

Owing to causes such as population aging, increased use of various medical devices, long-term hospitalization of various patients with reduced immune function such as cancer, diabetes, and organ transplant patients, and the growing size of hospitals, hospital infections are continuing to increase. As seen in the MERS crisis of 2015, hospital infections have become a social and national problem. In order to prevent damage due to such hospital infections, it is necessary to first strictly implement measures to prevent hospital infections, while, on the other hand, providing proper relief of damage suffered due to hospital infections. However, the mainstream attitude of judicial precedents relating to hospital infection cases has been judged to in fact shift responsibility over damages due to hospital infections on the patient. In light of the philosophy of the damage compensation system, whose guiding principle if the fair and proper apportionment of damages, there is a need to seek means of drastically relaxing the burden of proof on the patient's side relative to conventional legal principles for relaxing the burden of proof, or the theory of de facto estimation. In relation to such need, the German civil code (Burgerliches Gesetzbuch), which defines contracts of medical treatment as typical contracts under the civil code, and has presumption of negligence provisions stipulating that, in cases such as hospital infections which were completely under the control of the medical care providers, if risks in general medical treatment have been realized which cause violations of the life, body, or health of patients, error on the part of the person providing medical care is presumed, was examined. Contracts of medical treatment are entered into very frequently and broadly in the everyday lives of the general public, with various disputes owing thereto arising. Therefore, it is necessary to, by defining contracts of medical treatment as typical contracts under the civil code, regulate the content of said contracts, as well as the proof of burden when disputes arise. If stipulations in the civil code are premature as of yet, an option may be to regulate through a special act, as is the case with France. In the case of hospital infection cases, it is thought that 'legal presumption of negligence' relating to 'negligence in the occurrence of hospital infections,' which will create a state close to equality of arms, will aid the resolution of the realistic issue of the de facto impossibility of remedying damages occurring due to negligence in the process of occurrence of hospital infections. Also, even if negligence is presumed by law, as the patient side is burdened with proving the causal relationships, such drastic confusion as would occur if the medical care provider side is found fully liable if a hospital infection occurs may be avoided. It is thought that, alongside such efforts, social insurance policy must be improved so as to cover the expenses of medical institutions having strictly implemented efforts to prevent hospital infections in the event that they have suffered damages due to a hospital infection accident, and that close future research and examination into this matter will be required.

• The Korean Journal of Air & Space Law and Policy
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• v.17
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• pp.9-28
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• 2003

The Warsaw Convention of 1929 and the amendments thereto including the Hague Protocol, Montreal Protocols Nos. 1,2,3 and 4, the Guadalajara Convention and the IATA Intercarrier Agreements, which are the rules (as called "War saw System") have played as a major rule in the international air transportation for more than 70 years, will be replaced by the Montreal Convention of 1999 for its effectiveness on November 4, 2003. While a major portion of the Montreal Convention follows the language of the Warsaw System, the Montreal Convention makes significant changes to the scope and extent of the carrier's liability, expands the jurisdictions where the carrier can be sued, and recognizes the effect of code sharing on air carrier liability. The Montreal Convention heralds the single biggest change in the international aviation since the diplomatic efforts in the mid-1920's which resulted in the enactment of the Warsaw Convention. Until now, the legal liability of almost all the international air carriers has been governed by the Warsaw System. The Montreal Convention incorporates provisions of these instruments to create a single document and to set a uniform regime for carrier liability in international transportation. At the same time the issue of the low liability limits of the Warsaw has been resolved to a more satisfactory level in the Montreal Convention. The Convention has been hailed as consumer friendly and progressive in nature. If this Convention is ratified by Korea, the virtual elimination of the liability limits between the passengers and the airlines will become law by treaty. The airlines in Korea as well as Korean consumers of international air carriage will immensely benefit from the ratification. As opposed to the Warsaw Convention, the Montreal Convention has been described to be the one that is no longer a Convention for airlines, but it would serve the interests of both the consumers and the air carriers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.4
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• pp.11-20
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• 1983

This study investigates reliability based design criteria for the spiral R.C. columns, and proposes practical algorithm which is based on Ellingwood's algorithm for the reliability analysis and the derivation of reliability based design criteria. Cornell's MFOSM theory is used for the derivation of the algorithm for the evaluation of uncertainties associated with resistances, whereas the magnitude of the uncertainties associated with load effects are chosen primarily by considering our level of practice. And thus the uncertainties so obtained are applied for the relilability analysis and the derivation of reliability based design criteria. A target reliability (${\beta}_0=3.5$) is selected as an appropriate value by comparing the values used in foreign countries and by analyzing, the reliability levels of our current USD and WSD design standards. Then, a set of load and resistance factors corresponding to the target reliability is proposed as a reliability based design provision, and furthermore a set of allowable stresses for reinforcing steel and concrete having same level of reliability with the corresponding LRFD criteria is also propared for the current WSD design provision. It may be concluded that the proposed LRFD reliability based design provisions and the corresponding allowable stresses give more rational design than the current code for spiral R.C. columns.

• Journal of Korea Technology Innovation Society
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• v.10 no.3
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• pp.486-508
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• 2007

This study identifies key determinants of participation in UCC services. Incorporating insights from the flow theory, we examine the effects of psychological factors of social presence, self expression, arousal, and challenge as well as web-site characteristics variables of media easiness, contents usability, and immediateness. We have done a sample survey of internet users and collected 260 responses. Using Windows SPSS/PC 12.0 Package, we have performed statistical analyses including a correlation analysis, a factor analysis, and a multiple regression analysis. The result of the study is as follows. Psychological variables of perceived social presence, self expression, arousal, and challenge all show positive significant effect on participation in UCC service. Among web site characteristics, media easiness, which consists of a web structure that is easy-to-use, user friendliness, and personalized service, demonstrates a positive significant effect on participation in UCC services. Immediateness also has a positive significant effect. Some of the practical implications of the result are follows. We should improve user access to platforms of UCC service by opening up platforms. This will heighten perceived challenge which has the strongest influence on participation in UCC services. We need to focus on multimedia services and adjust to the cultural code of netizen who crave for visual expressions and on the spot on-line activities. Also suggested is that contributions made by participants need to be acknowledged through such provisions as profit sharing. Needs for individualized service, which is an aspect of media easiness, should also be addressed. Participants tend to value individuality while at the same time accepting broader trends. Information services need to be customized for individuals. In UCC centered internet businesses, netizen consumers are presumer. They are consumers and producers at the same time, and consumer needs should also be explored for the success of internet businesses.

• Journal of the Korea Concrete Institute
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• v.29 no.3
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• pp.275-281
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• 2017

This study examined the effect of water-to-binder ratio (W/B) and phosphate-to-binder ratio (P/B) on the flow, setting time, compressive strength development, and pH variation of magnesium-potassium phosphate composites, MKPC mortars. Ten mortars mixtures were prepared with the W/B varying from 20% to 40% at each P/B of 0.3 or 0.5. The hydration products and microstructural pore distribution of the MKPC pastes were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and mercury intrusion porosimetry (MIP). The initial flow and setting time of MKPC mortars tended to decrease with an increase of P/B, indicating that the final setting time was shortened by approximately 24% when P/B increased from 0.3 to 0.5. The slope of the early-strength development measured in the MKPC mortars was considerably higher than that of cement concrete specified in code provisions. For obtaining a relatively good 28-day strength (above 30 MPa) and a near neutral pH (below 9.0) in MKPC mortars, the P/B and W/B need to be selected as 0.5 and 30%, respectively. The strubite-K crystal increased with the increases of P/B and W/B, which leads to the decrease of the macro-capillary pores.