• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.4
• /
• pp.733-738
• /
• 2005

The distress communication system in the maritime mobile service had almost depended on the wireless telephony or telegraphy technique. The GMDSS (Global Maritime Distress and Safety System) which was introduced in 1992 brought a lot of changes in the maritime distress communication service such as the automatic transmission of distress signals and implementation of global search and rescue networks. However, there are some deficiencies in the GMDSS distress communication system such as a lack of compatibility in the maritime distress communication between CMDSS ships and Non-GMDSS ships, increasing deceptive or false distress alerts generated by GMDSS installations, lack of understanding about the CMDSS installations for the operators. In this paper, the problems of distress communication system in the maritime mobile service are analyzed and the methods to solve or minimize these problems are suggested.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.13 no.1
• /
• pp.35-45
• /
• 2001

The sea dike at Gun-Jang Industry Area had been constructed recently and both inside and outside areas of the dike show harmonic behaviour. To examine stability against piping, 2 dimensional seepage analysis was executed using finite element method. To investigate the harmonic motion of water level, unsteady and unsaturated flow analysis is needed, and specially harmonic motion in the both areas from the dike should be considered, Water level recorder was used to obtain tidal harmonic data, and sieve analysis has been earried out so that the distribution of grain diameter of the dike material is clearly informed. The calculated velocity was compared with critical velocity.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• autumn
• /
• pp.279-284
• /
• 2001

The owner's evaluation system about the contractor's work performance is used to give the contractor some advantages or disadvantages. According to the result of evaluation of the contractor's performance in the given construction project, the owner identify the good contractors and give them some merits in the future project bidding. However, the system used in the Korean construction industry has caused many problems and has been operated improperly. As a case study, this paper investigates the current problems existed in the KNHC (Korean National Housing Corporation) evaluation system and suggests some directions for its efficient operation. In doing so, the study performed interviews with the KNHC officers and the related contractors, using a structured questionnaire

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2007.04a
• /
• pp.168-171
• /
• 2007

A technical review of current slurry and gelled propellants is presented. In advanced countries, it is confirmed that these propellants have high specific impulse, density, excellent handling, safety characteristics and thrust controllability through research since 1950s. Substantial researches have been pursued to characterize the rheological properties, spray/combustion phenomena and propulsion system design for the gel propellant characteristics. Slurry and gelled propellants are developing actively to applicate both military and space propulsion fields such as tactical missile, air-breathing ramjet, pulse detonation engine, and combined cycle engine of future propulsion mode.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.22 no.3
• /
• pp.8-13
• /
• 2018

Zirconium potassium perchlorate(ZPP) is an igniter composed of potassium perchlorate as an oxidizing agent and zirconium as a fuel with a Viton binder. ZPP has been used to provide an ignition source in the aerospace, propulsion, and automotive industries. This study investigates the manufacturing process and characteristics of ZPP, such performance and shape/calorimetry/pressure characteristics with respect to pyrotechnic mechanical device(PMD). During the production of ZPP, the mixing process was designed to produce uniform particle size and shape by mixing the raw materials at high speed.

• Journal of the Korea Institute of Building Construction
• /
• v.10 no.1
• /
• pp.101-109
• /
• 2010

Under the Civil Code and related law in Korea, the liability for defects after delivery belongs to the Contractor. However, various disputes have occurred in relation to the remedy of such defects and the compensation for damages, which are the main liability of a contractor in the event of defects. Despite court decisions regarding defect liability, many problems prevail in the real world. For this reason, this working-level research considers the introduction of a performance warranty contract system. To establish the system successfully, it is necessary to analyze the trend of various warranty cases in the US. Therefore, the warranty system of the US was first examined, and the effect of acceptance, notification and burden of proof, remedies under warranty clauses, and default termination were investigated and analyzed in this study.

• Journal of the Korean Chemical Society
• /
• v.55 no.2
• /
• pp.268-278
• /
• 2011

Corrosion of aluminum in 0.1 M HCl solution in the absence and presence of ${\beta}$-blocker inhibitors (atenolol, propranolol, timolol and nadolol) was investigated using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The inhibition efficiency increased with inhibitor concentration and decreased with rise of temperature. Potentiodynamic polarization curves revealed that they acted as cathodic inhibitors. Some thermodynamic parameters were calculated and discussed. All inhibitors were adsorbed on Al surface obeying Frumkin isotherm. All EIS tests exhibited one capacitive loop which indicates that the corrosion reaction is controlled by charge transfer process. The inhibition efficiencies of all test methods were in good agreement.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.1176-1179
• /
• 2017

In this study, internal ballistic analysis theories of dual-thrust solid rocket motor using two kinds of propellant are found, and the theories are applied to develop internal ballistic analysis model. Internal ballistic analysis which is dual-thrust solid rocket motor using two kinds of propellant is carried out an applying of the random figures of two kinds of propellant and an analyze of the test results. Through this analytical model was able to an applying internal ballistic analysis for dual-thrust solid rocket motor using two kinds of propellant.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.445-450
• /
• 2017

ZPP(Zirconium Potassium Perchlorate) is an igniter composed of potassium perchlorate as oxidizing agent and zirconium as fuel with a Viton binder. ZPP is used to provide ignition in the aerospace, propulsion, automotive industries. This research is investigated for the manufacturing process and characteristics analysis of the ZPP such as the performance and shape/calorimetry/pressure characteristics of the ZPP on PMD(Pyrotechnic Mechanical Device). During the production of ZPP, the mixing process was designed so that the ZPP could be produced in uniform particle size and shape by mixing the raw materials at high speed.

• The Korean Journal of Applied Statistics
• /
• v.18 no.3
• /
• pp.521-532
• /
• 2005

In the current College Scholastic Aptitude Test (CSAT), the standardized scoring system is being adopted to adjust te differences of degrees of difficulty between the optional subjects. But it becomes clear that the system has several weak points, some of which are considered to be very serious. In this paper we propose an alternative method, so-called the additive scoring system. It determines the additional points per each subjects, according to the subject mean scores. The proposed method has been simulated using the data of 2005' CSAT, and it turns out that the additive scoring system reduces or remove the troubles caused by the standardized scoring system.