• Journal of the Society of Naval Architects of Korea
• /
• v.28 no.2
• /
• pp.275-284
• /
• 1991

Fatigure crack growth from surface defects is one of the most important subjects for the evaluation and the assurance of safety in pressure vessels, piping systems, ship hulls and other various structures. This paper attempts to analysis some practical or general problems such as the estimation of crack growth life to penetrate the plate thickness, based on fatigure crack growth from a single surface flaw and the interaction of multiple flaws. An experiment on the coalescence of multiple undercuts was carried out under cyclic tension condition as a attempt to the analysis of multiple crack problems. It is noted that the fracture strength is characterized by the analogy to that in a single crack growth.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.2C
• /
• pp.10-15
• /
• 2005

In this paper, a simple but fast and reliable technique for the complex dielectric constant measurement of non-magnetic materials is introduced using a measured transmission coefficient (S21) and a genetic algorithm as an inversion process at microwave frequencies. In this experiment, it has been found that the transmission method is less susceptible with the measurement errors than that of the reflection method and the genetic algorithm can be efficiently used as a search technique. The suggested technique is validated with known and unknown conductor-loaded lossy materials and the conductor-loaded PCB at X-band.

• Information and Communications Magazine
• /
• v.13 no.11
• /
• pp.181-191
• /
• 1996

In this paper we discuss narrow-band interference rejection schemes for spectrum overlay communications where direct sequence spread spectrum (DS/SS) communication system and narrow-band communication systems share the same frequency band. In this case, it is essential to reject the narrow-band signals to guarantee the performance of DS/SS system, while it is not necessarily required to reject the DS/SS signal to recover the narrow-band signal. We discuss several schemes such as time domain processing, frequency domain processing and exploiting the device characteristics to reduce the effect of narrow-band signal on DS/SS communication systems. Furthermore, we suggest a structure of tunable notch filter using gyrator that can easily be customized to ASIC.

• Journal of KIISE:Information Networking
• /
• v.29 no.1
• /
• pp.48-56
• /
• 2002

This paper proposes an IP(Internet Protocol) multicast routing method by multiple tree routes. Multiple trees, instead of a single tree, improve the quality of multicast services with nonlinear link cost and huge traffic demand. The proposed method adds tree routes until it satisfies target conditions, and it splits the multicast traffic demand into the chosen tree routes. We develop a mathematical model and optimal conditions for traffic splitting. The method works on the problems with many different simultaneous multicast traffic. Various experiments were carried and the results show that the new multicasting is fairly effective on end-to-end quality of services.

• Korea Trade Review
• /
• v.42 no.3
• /
• pp.101-121
• /
• 2017

This article investigates the negotiation landscape of WTO ITA(Information Technology Agreement) expansion negotiation which is the most recently concluded plurilateral trade agreement under WTO. Using the trade flow data of each country and product, this study explores analytical indicators to identify the overall characteristics of the negotiation and negotiation position each participant might make. Results identified that the negotiation was generally led by export-oriented countries, especially East Asian countries. Country level negotiation positions at each sub-sector are also discussed in this study.

• The Journal of the Korea Contents Association
• /
• v.8 no.10
• /
• pp.54-63
• /
• 2008

With the improvement of computer performance in Mobile Environments, the users demand for the multimedia player is getting higher, which will be the major force behind the wide distribution of the media player that allows several moving pictures to run simultaneously using multiple windows on the screen. Products that adopted the same method used for a single moving picture and yet support the several moving pictures simultaneously emerged; however, they are not immune from problems. In this paper, we propose method to solve the problems of blinking, play prioritization processor and semi-transparent processor that occur when appling several moving pictures to the method used for a single moving picture and suggested the possible solutions. Taking it one step further, it focused on design and implementation of the media player that allows several moving pictures using overlapping and overlay technique by recognizing the biggest problem, which is that the above media play is not supported when playing several moving pictures simultaneously.

• Journal of Internet Computing and Services
• /
• v.7 no.3
• /
• pp.133-142
• /
• 2006

The purpose of the multiple key agreement protocol is to get efficiency in computational and communicational aspects compared to multiple executions of single key agreement protocol. However ID based tripartite multiple key agreement protocols have been proposed, it is reported that they can not resist unknown key-share attack or impersonation attack. How to design a secure and efficient ID-based authenticated tripartite multiple key agreement scheme to prevent all kinds of attacks remains an open problem. This paper proposes a multiple key agreement scheme combing the existing single key agreement protocol with a key derivation function. The proposed scheme can not only increase computational efficiency compared to the existing multiple key agreement protocol, but can ensure security of the proposed schemes by using a security proofed single key agreement protocol and key derivation function.

• Clinical and Experimental Pediatrics
• /
• v.49 no.10
• /
• pp.1106-1110
• /
• 2006

Chylous ascites is a rare condition caused by various diseases and conditions that interfere with the abdominal or retroperitoneal lymphatics, and uncommonly it can manifest as a post-operative complication after abdominal, retroperitoneal or mediastinal surgery. Chylous ascites can be diagnosed by a high triglyceride content in ascites. The authors experienced a 5-year-old girl with congenital hepatic fibrosis who presented with chylous ascites after a splenorenal shunt operation, who was successfully managed by fasting and total parenteral nutrition, followed by a lipid-free diet with medium chain triglyceride supplementation. Here, the authors report this case of post-operative chylous ascites after a splenorenal shunt (Warren shunt) operation with a review of the pertinent literature.

• Clinical and Experimental Reproductive Medicine
• /
• v.36 no.2
• /
• pp.137-142
• /
• 2009

Ovarian hyperstimulation syndrome (OHSS) is one of the most common iatrogenic complications induced by assisted reproductive technology. Hydrothorax develops in about 10 percent of patients with severe OHSS and it is usually associated with marked ascites. On the other hand, severe hydrothorax without marked ascites is uncommon, and its pathogenesis remains unclear. We recently experienced a case of severe unilateral hydrothorax with minimal ascites induced by quintuplet pregnancy following intrauterine insemination with controlled ovarian hyperstimulation. Severe hydrothorax was resolved after only conservative and symptomatic management without invasive procedure such as thoracentesis or paracentesis. We report this case with brief review of literature.

• Journal of Korea Multimedia Society
• /
• v.6 no.6
• /
• pp.1015-1024
• /
• 2003

With the improvement of the computer performance, the users demand for the multimedia player is getting higher, which will be the major force behind the wide distribution of the media player that allows several moving pictures to run simultaneously using multiple windows on the screen. Products that adopted the same method used for a single moving picture and yet support the several moving pictures simultaneously emerged; however, they are not immune from problems. In this paper, we propose method to solve the problems of blinking, play prioritization processor and semi-transparent Processor that occur when appling several moving pictures to the method used for a single moving picture and suggested the possible solutions. Taking it one step further, it focused on design and implementation of the media player that allows several moving pictures using overlapping and overlay technique by recognizing the biggest problem, which is that the above media play is not supported when playing several moving pictures simultaneously.