• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.1 no.1
• /
• pp.21-32
• /
• 1981

Recent trends in design standards development in some European countries and U.S.A. have encouraged the use of probabilistic limit sate design concepts. Reliability based design criteria such as LSD, LRFD, PBLSD, adopted in those advanced countries have the potentials that they afford for symplifying the design process and placing it on a consistent reliability bases for various construction materials. A reliability based design criteria for RC flexural members are proposed in this study. Lind-Hasofer's invariant second-moment reliability theory is used in the derivation of an algorithmic reliability analysis method as well as an iterative determination of load and resistance factors. In addition, Cornell's Mean First-Order Second Moment Method is employed as a practical tool for the approximate reliability analysis and the derivation of design criteria. Uncertainty measures for flexural resistance and load effects are based on the Ellingwood's approach for the evaluation of uncertainties of loads and resistances. The implied relative safety levels of RC flexural members designed by the strength design provisions of the current standard code were evaluated using the second moment reliability analysis method proposed in this study. And then, resistance and load factors corresponding to the target reliability index(${\beta}=4$) which is considered to be appropriate level of reliability considering our practices are calculated by using the proposed methods. These reliability based factors were compared to those specified by our current ultimate strength design provisions. It was found that the reliability levels of flexural members designed by current code are not appropriate, and the code specified resistance and load factors were considerably different from the reliability based resistance and load factors proposed in this study.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2007.12a
• /
• pp.51-55
• /
• 2007

This thesis deals with the legal principles, case law decisions and suggestions for the Sale & Purchase of ships concerning enactment proposal of maritime law. Recently, the shipbuilding market has shown a major shift towards East Asia, particularly Korea, Japan and China. The major Korean shipyards in particular have engaged in substantial investment programmes both to expand their overall shipbuilding capacity and to enter new markets, such as for liquefied natural gas(LNG) carriers. The Korean Government has recently taken interest in the sale & purchase of used ships, utilizing the Internet and has made plans for building the Shipping Exchange in korea. So this thesis examines the situation of the world's shipping industry and the different kinds of the Sale & Purchase of ships. deals with the legal principles, and case law decisions. describes Forms of Shipbuilding Contracts and Memorandums of Agreement of second-hand ships. And makes suggestions for 1) the Shipbuilding Contracts of the shipowner's Association of Korea and 2) The Korean Shipbrokers' Association's Memorandum of Agreement for Ship Sale & Purchase in the korean shipping industry. Having reached the end of this thesis. the writer suggests to make terms of sale of ships in the korean civil code and commercial code, Additionally. the writer suggests to make a special law in relation to the Sale & Purchase of ships. Furthermore, the writer suggests expanding the Shipping Exchange in Korea.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.13 no.2
• /
• pp.29-40
• /
• 2010

Car simulation by TRANSIMS is able to rapidly analyze the broad area based on CA(Cellular Automata) theory, which is the great advantage compared to other existing programs. As the source code of TRANSIMS is open, it may be modified by incorporating the network and traffic characteristics. This study uses the traffic thematic map built in the Korean National Traffic DB(KTDB) center among input date used for building network data of TRANSIMS. However, because the traffic thematic map is not composed as the type required by TRANSIMS, it was corrected and complemented to build a network, and the traffic volume at arterial roads and the traffic volume at each direction of the intersection was calculated through simulation for the area of Suseong-Gu, Daegu Metro. This was compared to the actual traffic volume. As a result of the simulation, it shows error from 14% to 42% at intersection, and from 3% to 8% at arterial roads. This result is very satisfactory because the entire traffic volume of Daegu Metro was not considered, and the tendency of drivers avoiding path due to construction on certain section, the status of road surface and chronic congestion was not reflected.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.6
• /
• pp.562-575
• /
• 2023

In an effort to improve water quality, the South Korean government has implemented measures to increase seawater circulation in Saemangeum Lake. We analyzed the effect of increasing the frequency of seawater circulation based on salinity levels and bottom water exchange in the lake, using an environmental fluid dynamics code model. When the sluice gate opening and shutting frequency increased from once to twice per day, the internal water level of Saemangeum Lake increased by up to ~0.7 m. The salinity increased by 2.12 psu near the western breakwater and decreased by 1.18 psu near the freshwater inlet. We analyzed the extent of bottom water exchange using a particle tracing method and observed that the residual rate of particles shallower than 5 m in water depth decreased by 2.52% in Case 2 (opening and shutting twice per day) compared to Case 1 (opening and shutting once per day). This indicates that increasing the frequency of sluice gate opening and shutting would promote enhanced bottom water exchange. Consequently, the increased salinity and bottom water exchange associated with increased seawater circulation are expected to improve water quality in Saemangeum Lake.

• Journal of the Korean GEO-environmental Society
• /
• v.13 no.10
• /
• pp.33-42
• /
• 2012

The efficiency of the current design methods for computing pile resistances is analyzed using field load-settlement tests results. Twelve load-settlement test data for drilled shafts and bored piles were obtained from the literature. These load-test data were fitted using the t-z method. Subsequently, the ultimate resistances were evaluated based upon the failure criteria from following methods: (1) the Davisson's approach and (2) settlement corresponding to 5% or 10% shaft diameter approach. The ultimate resistances for these drilled shafts and bored piles were also predicted using methods based on the design code from North America (United States, Canada), Europe, and Asia (Japan). The pile resistances determined from field load-settlement tests were compared with those calculated using the design codes. The comparisons show that most design codes predict a conservative resistance for drilled shafts and bored piles. However, in the case of drilled shafts, we find that some of the design codes can over-predict the resistance and, therefore, should be applied cautiously. This research also shows that the t-z method can be successfully used to predict the ultimate resistance and the load transfer mechanism for a single pile.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.18 no.4
• /
• pp.269-282
• /
• 2006

We numerically studied tsunami propagation characteristics through Korean Straits based on nonlinear shallow water equation, a robust wave driver of the near field tsunamis. Tsunamis are presumed to be generated by the earthquake in Tsuhima-Koto fault line. The magnitude of earthquake is chosen to be 7.5 on Richter scale, which corresponds to most plausible one around Korean peninsula. It turns out that it takes only 60 minutes for leading waves to cross Korean straits, which supports recently raised concerns at warning system might be malfunctioned due to the lack of evacuation time. We also numerically obtained the probability of tsunami inundation of various levels, usually referred as tsunami hazard, along southern coastal area of Korean Peninsula based on simple seismological and Kajiura (1963)'s hydrodynamic model due to tsunami-generative earthquake in Tsuhima-Koto fault line. Using observed data at Akita and Fukaura during Okushiri tsunami in 1993, we verified probabilistic model of tsunami height proposed in this study. We believe this inundation probability of various levels to give valuable information for the amendment of current building code of coastal disaster prevention system to tame tsunami attack.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.6
• /
• pp.250-255
• /
• 2017

When an earthquake occurs, it is necessary to evaluate the site-specific ground response while considering ground characteristics in seismic design. The design seismic force of Korean seismic design criteria is borrowed from the Uniform Building Code(UBC-1997). However, the criteria are based on the ground characteristics of the United States, which are different from the ground characteristics in Korea, and using them could cause over-or under-designing. Therefore, it is important to develop a proper design response spectrum for Korean ground characteristics. In this study, 158 ground sites in Korean urban areas were selected and compared to those in the western part of the United States, and their site-specific ground responses were analyzed. The classification standard in the seismic design criteria classifies the 158 sites into 37 sites, 107 sites, and 14 sites. Using 7 earthquake inputs, the criteria were compared for each group.The Korean design response spectrum underestimates the amplification of the short-period range and overestimates the amplification in the long-period range. There were large differences in the results of the and sites,which account for 77 percent of the 158 sites. Therefore, there is a need to modify the amplification factor in the Korean seismic criteria to properly reflect Korean ground characteristics.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.36
• /
• pp.3-26
• /
• 2007

This article attempts to describe and analyze discussions on the matter of ex tunc effect or a ex nunc effect of rescission under Korean law in comparison with those under the CISG). In addition, it tries to scrutinize the various rules on the right to damages as an effect of rescission in a comparative way. Furthermore, it compares the various rules of Korean law with the CISG as to the right to damages and evaluates them in light of the discipline of comparative law. It maintains that the liquidation theory in Korean law is more close to the CISG in that there is no ex tunc effect in rescission and in other aspects. It also argues that the construction of the effects of rescission in accordance with the liquidation theory is more plausible when one considers Korea is one of the contracting states of the CISG. In addition, the theoretical analysis and the comparative study with the CISG shows that the insistence of ex nunc effect and its interpretation on the scope of damages extends to damages for expectation interest. It is also submitted that the position under the CISG on the assumption of ex nnuc effect, is regretted in that the restitution in value of the goods in the event of impossibility of the physical restitution is not allowed in some cases which the damage claims can not be awarded for the seller due to the application of the CISG Art. 79.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.17
• /
• pp.7-35
• /
• 2002

In many international financing transactions Korean companies are required to issue a guarantee. Thus far, however, legal issues on international guarantees have not been fully discussed in Korea. This is partly because most of the international guarantees are governed by a foreign law such as English law or the laws of the State of New York. In this articles the author examines major concepts or terms and conditions of a typical international guarantee, e.g., language on consideration, primary obligor, joint and several guarantee, unconditional and irrevocable guarantee, continuing guarantee, right of subrogation, representations and warranties, covenant or undertaking, currency indemnity, assignment, participation, governing law and jurisdiction clause, etc. For reference, standard forms of a guarantee and a standby letter of credit are attached to the article. In examining the terms and conditions, the author compares them with similar or equivalent concepts under Korean law. The author further discusses some Korean law issues that may arise under international guarantees governed by a foreign law. These issues include the application of the ultra vires doctrine under Article 34 of the Civil Code of Korea, the validity of an international guarantee which a Korean company has issued in violation of the guarantee ceiling set under Article 10 of the Law on Monopoly Regulation and Fair Trade of Korea and the validity of an international guarantee which a Korean party has issued in violation of the Foreign Exchange Transaction Law. In addition, the author discusses some issues under a so-called independent guarantee and a standby letter of credit. In this regard, reference is made to the Uniform Rules for Demand Guarantee (URDG), International Standby Practices (ISP98) and the Convention on Independent Guarantees and Stand-by Letters of Credit adopted by the United Nations in 1995. Finally, the author examines major terms and conditions of typical comfort letters and discusses some legal issues, such as the binding force of the comfort letter. In dealing with the issues the author underscores that to the extent the issues are not properly dealt with by an international norm such as Uniform Customs and Practice for Documentary Credits or ISP 98, the issues must be analyzed by reference to the governing law of the relevant instrument.

• Korean Journal of Construction Engineering and Management
• /
• v.16 no.4
• /
• pp.60-69
• /
• 2015

Labor attendance management has traditionally been carried out by writing a table for checking an attendance of labor, which requires a lot of time and effort. As electronic devices with additions such as barcodes, Quick Response codes, and Radio Frequency Identification(RFID) have been developed, however, automated labor attendance management systems have appeared. Recently, various types of labor recognition devices converged with biometrics (fingerprint, vein, face recognition, etc.) have been released. However, although these devices can be used to check attendance automatically, there is insufficient guidance when it comes to selecting the appropriate labor attendance management system for construction sites. Therefore, this study proposed a decision framework to determine which labor attendance management system would be suitable for a construction site and to select the labor recognition device. This study investigated different labor recognition devices, focusing on how they worked, and tested the performance of devices and their usability for construction labor attendance management. The test results showed that RFID is most suitable when verifying the attendance of many laborers over a short period of time. The devices for hand vein and fingerprint recognition did not function when there was a foreign material such as cement or paint on the laborer's hand, except for a deformed finger. Reflecting these test results, this study suggested a framework for selecting a labor attendance system and recognition device; this is expected to contribute to the development of more efficient labor management systems.